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金融体制、融资约束与投资——来自OECD的实证分析R．SemenovDepartment of Economics，University of Nijmegen，Nijmegen（荷兰内梅亨大学，经济学院）这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时，我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致，并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。
一、引言各个国家的企业在显著不同的金融体制下运行。
金融发展水平的差别(例如，相对GDP的信用额度和相对GDP的相应股票市场的资本化程度），在所有者和管理者关系、企业和债权人的模式中，企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。
然而，经济理论表明市场摩擦，诸如信息不对称和激励问题会使获得外部资本更加昂贵，并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素，例如内部产生资金数量、新债务和权益的可得性，共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料（可参考，例如Fazzari（1998）、 Hoshi(1991)、 Chapman（1996）、Samuel(1998））.大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。
这项研究结果解释表明企业投资受限于外部资金的可得性。
很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本，减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置（参看Levine（1997)的评论文章）。
因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。
本科生毕业设计(论文）外文原文及译文所在系管理系学生姓名专业财务管理班级学号指导教师2014 年 6 月外文原文及译文Cost ControlRoger J. AbiNaderReference for Business，Encyclopedia of Business, 2nd ed。
Cost control，also known as cost management or cost containment，is a broad set of cost accounting methods and management techniques with the common goal of improving business cost-efficiency by reducing costs, or at least restricting their rate of growth. Businesses use cost control methods to monitor, evaluate, and ultimately enhance the efficiency of specific areas，such as departments，divisions, or product lines, within their operations.Cooper and Kaplan in 1987 in an article entitled "how cost accounting systematically distorts product costs” article for the first time put forward the theory of "cost drivers" (cost driver, cost of driving factor）of that cost, in essence，is a function of a variety of independent or interaction of factors （independent variable) work together to drive the results. So what exactly is what factors drive the cost or the cost of motive which? Traditionally, the volume of business (such as yield）as the only cost driver （independent variable)，at least that its cost allocation plays a decisive role in restricting aside，regardless of other factors (motivation）. In accordance with the full cost of this cost driver, the enterprise is divided into variable costs and fixed costs of the two categories。
北京联合大学毕业设计（论文）任务书题目：OFDM调制解调技术的设计与仿真实现专业：通信工程指导教师：张雪芬学院：信息学院学号：2011080331132班级：1101B姓名：徐嘉明一、外文原文Evolution Towards 5G Multi-tier Cellular WirelessNetworks:An Interference ManagementPerspectiveEkram Hossain, Mehdi Rasti, Hina Tabassum, and Amr AbdelnasserAbstract—The evolving fifth generation (5G) cellular wireless networks are envisioned to overcome the fundamental challenges of existing cellular networks, e.g., higher data rates, excellent end-to-end performance and user-coverage in hot-spots and crowded areas with lower latency, energy consumption and cost per information transfer. To address these challenges, 5G systems will adopt a multi-tier architecture consisting of macrocells, different types of licensed small cells, relays, and device-to-device (D2D) networks to serve users with different quality-of-service (QoS) requirements in a spectrum and energy-efficient manner. Starting with the visions and requirements of 5G multi-tier networks, this article outlines the challenges of interference management (e.g., power control, cell association) in these networks with shared spectrum access (i.e., when the different network tiers share the same licensed spectrum). It is argued that the existing interference management schemes will not be able to address the interference management problem in prioritized 5G multitier networks where users in different tiers have different priorities for channel access. In this context, a survey and qualitative comparison of the existing cell association and power control schemes is provided to demonstrate their limitations for interference management in 5G networks. Open challenges are highlighted and guidelines are provided to modify the existing schemes in order to overcome these limitations and make them suitable for the emerging 5G systems.Index Terms—5G cellular wireless, multi-tier networks, interference management, cell association, power control.I. INTRODUCTIONTo satisfy the ever-increasing demand for mobile broadband communications, the IMT-Advanced (IMT-A) standards have been ratified by the International Telecommunications Union (ITU) in November 2010 and the fourth generation (4G) wireless communication systems are currently being deployed worldwide. The standardization for LTE Rel-12, also known as LTE-B, is also ongoing and expected to be finalized in 2014. Nonetheless, existing wireless systems will not be able to deal with the thousand-fold increase in total mobile broadband data [1] contributed by new applications and services such as pervasive 3D multimedia, HDTV, VoIP, gaming, e-Health, and Car2x communication. In this context, the fifth generation (5G) wireless communication technologies are expected to attain 1000 times higher mobile data volume per unit area,10-100 times higher number of connecting devices and user data rate, 10 times longer battery life and 5 times reduced latency [2]. While for 4G networks the single-user average data rate is expected to be 1 Gbps, it is postulated that cell data rate of theorder of 10 Gbps will be a key attribute of 5G networks.5G wireless networks are expected to be a mixture of network tiers of different sizes, transmit powers, backhaul connections, different radio access technologies (RATs) that are accessed by an unprecedented numbers of smart and heterogeneous wireless devices. This architectural enhancement along with the advanced physical communications technology such as high-order spatial multiplexing multiple-input multiple-output (MIMO) communications will provide higher aggregate capacity for more simultaneous users, or higher level spectral efficiency, when compared to the 4G networks. Radio resource and interference management will be a key research challenge in multi-tier and heterogeneous 5G cellular networks. The traditional methods for radio resource and interference management (e.g., channel allocation, power control, cell association or load balancing) in single-tier networks (even some of those developed for two-tier networks) may not be efficient in this environment and a new look into the interference management problem will be required.First, the article outlines the visions and requirements of 5G cellular wireless systems. Major research challenges are then highlighted from the perspective of interference management when the different network tiers share the same radio spectrum. A comparative analysis of the existing approaches for distributed cell association and power control (CAPC) is then provided followed by a discussion on their limitations for5G multi-tier cellular networks. Finally, a number of suggestions are provided to modifythe existing CAPC schemes to overcome these limitations.II. VISIONS AND REQUIREMENTS FOR 5G MULTI-TIERCELLULAR NETWORKS5G mobile and wireless communication systems will require a mix of new system concepts to boost the spectral and energy efficiency. The visions and requirements for 5G wireless systems are outlined below.·Data rate and latency: For dense urban areas, 5G networks are envisioned to enable an experienced data rate of 300 Mbps and 60 Mbps in downlink and uplink, respectively, in 95% of locations and time [2]. The end-to- end latencies are expected to be in the order of 2 to 5 milliseconds. The detailed requirements for different scenarios are listed in [2].·Machine-type Communication (MTC) devices: The number of traditional human-centric wireless devices with Internet connectivity (e.g., smart phones, super-phones, tablets) may be outnumbered by MTC devices which can be used in vehicles, home appliances, surveillance devices, and sensors.·Millimeter-wave communication: To satisfy the exponential increase in traffic and the addition of different devices and services, additional spectrum beyond what was previously allocated to 4G standard is sought for. The use of millimeter-wave frequency bands (e.g., 28 GHz and 38 GHz bands) is a potential candidate to overcome the problem of scarce spectrum resources since it allows transmission at wider bandwidths than conventional 20 MHz channels for 4G systems.·Multiple RATs: 5G is not about replacing the existing technologies, but it is about enhancing and supporting them with new technologies [1]. In 5G systems, the existing RATs, including GSM (Global System for Mobile Communications), HSPA+ (Evolved High-Speed Packet Access), and LTE, will continue to evolve to provide a superior system performance. They will also be accompanied by some new technologies (e.g., beyondLTE-Advanced).·Base station (BS) densification: BS densification is an effective methodology to meet the requirements of 5G wireless networks. Specifically, in 5G networks, there will be deployments of a large number of low power nodes, relays, and device-to-device (D2D) communication links with much higher density than today’s macrocell networks.Fig. 1 shows such a multi-tier network with a macrocell overlaid by relays, picocells, femtocells, and D2D links. The adoption of multiple tiers in the cellular networkarchitecture will result in better performance in terms of capacity, coverage, spectral efficiency, and total power consumption, provided that the inter-tier and intratier interferences are well managed.·Prioritized spectrum access: The notions of both trafficbased and tier-based Prioriti -es will exist in 5G networks. Traffic-based priority arises from the different requirements of the users (e.g., reliability and latency requirements, energy constraints), whereas the tier-based priority is for users belonging to different network tiers. For example, with shared spectrum access among macrocells and femtocells in a two-tier network, femtocells create ―dead zones‖ around them in the downlink for macro users. Protection should, thus, be guaranteed for the macro users. Consequently, the macro and femtousers play the role of high-priority users (HPUEs) and lowpriority users (LPUEs), respectively. In the uplink direction, the macrocell users at the cell edge typically transmit with high powers which generates high uplink interference to nearby femtocells. Therefore, in this case, the user priorities should get reversed. Another example is a D2D transmission where different devices may opportunistically access the spectrum to establish a communication link between them provided that the interference introduced to the cellular users remains below a given threshold. In this case, the D2D users play the role of LPUEs whereas the cellular users play the role of HPUEs.·Network-assisted D2D communication: In the LTE Rel- 12 and beyond, focus will be on network controlled D2D communications, where the macrocell BS performs control signaling in terms of synchronization, beacon signal configuration and providing identity and security management [3]. This feature will extend in 5G networks to allow other nodes, rather than the macrocell BS, to have the control. For example, consider a D2D link at the cell edge and the direct link between the D2D transmitter UE to the macrocell is in deep fade, then the relay node can be responsible for the control signaling of the D2Dlink (i.e., relay-aided D2D communication).·Energy harvesting for energy-efficient communication: One of the main challenges in 5G wireless networks is to improve the energy efficiency of the battery-constrained wireless devices. To prolong the battery lifetime as well as to improve the energy efficiency, an appealing solution is to harvest energy from environmental energy sources (e.g., solar and wind energy). Also, energy can be harvested from ambient radio signals (i.e., RF energy harvesting) with reasonable efficiency over small distances. The havested energy could be used for D2D communication or communication within a small cell. Inthis context, simultaneous wireless information and power transfer (SWIPT) is a promising technology for 5G wireless networks. However, practical circuits for harvesting energy are not yet available since the conventional receiver architecture is designed for information transfer only and, thus, may not be optimal for SWIPT. This is due to the fact that both information and power transfer operate with different power sensitivities at the receiver (e.g., -10dBm and -60dBm for energy and information receivers, respectively) [4]. Also, due to the potentially low efficiency of energy harvesting from ambient radio signals, a combination of different energy harvesting technologies may be required for macrocell communication.III. INTERFERENCE MANAGEMENT CHALLENGES IN 5GMULTI-TIER NETWORKSThe key challenges for interference management in 5G multi-tier networks will arise due to the following reasons which affect the interference dynamics in the uplink and downlink of the network: (i) heterogeneity and dense deployment of wireless devices, (ii) coverage and traffic load imbalance due to varying transmit powers of different BSs in the downlink, (iii) public or private access restrictions in different tiers that lead to diverse interference levels, and (iv) the priorities in accessing channels of different frequencies and resource allocation strategies. Moreover, the introduction of carrier aggregation, cooperation among BSs (e.g., by using coordinated multi-point transmission (CoMP)) as well as direct communication among users (e.g., D2D communication) may further complicate the dynamics of the interference. The above factors translate into the following key challenges.·Designing optimized cell association and power control (CAPC) methods for multi-tier networks: Optimizing the cell associations and transmit powers of users in the uplink or the transmit powers of BSs in the downlink are classical techniques to simultaneously enhance the system performance in various aspects such as interference mitigation, throughput maximization, and reduction in power consumption. Typically, the former is needed to maximize spectral efficiency, whereas the latter is required to minimize the power (and hence minimize the interference to other links) while keeping theFig. 1. A multi-tier network composed of macrocells, picocells, femtocells, relays, and D2D links.Arrows indicate wireless links, whereas the dashed lines denote the backhaul connections. desired link quality. Since it is not efficient to connect to a congested BS despite its high achieved signal-to-interference ratio (SIR), cell association should also consider the status of each BS (load) and the channel state of each UE. The increase in the number of available BSs along with multi-point transmissions and carrier aggregation provide multiple degrees of freedom for resource allocation and cell-selection strategies. For power control, the priority of different tiers need also be maintained by incorporating the quality constraints of HPUEs. Unlike downlink, the transmission power in the uplink depends on the user’s batt ery power irrespective of the type of BS with which users are connected. The battery power does not vary significantly from user to user; therefore, the problems of coverage and traffic load imbalance may not exist in the uplink. This leads to considerable asymmetries between the uplink and downlink user association policies. Consequently, the optimal solutions for downlink CAPC problems may not be optimal for the uplink. It is therefore necessary to develop joint optimization frameworks that can provide near-optimal, if not optimal, solutions for both uplink and downlink. Moreover, to deal with this issue of asymmetry, separate uplink and downlink optimal solutions are also useful as far as mobile users can connect with two different BSs for uplink and downlink transmissions which is expected to be the case in 5G multi-tier cellular networks [3].·Designing efficient methods to support simultaneous association to multiple BSs: Compared to existing CAPC schemes in which each user can associate to a singleBS, simultaneous connectivity to several BSs could be possible in 5G multi-tier network. This would enhance the system throughput and reduce the outage ratio by effectively utilizing the available resources, particularly for cell edge users. Thus the existing CAPCschemes should be extended to efficiently support simultaneous association of a user to multiple BSs and determine under which conditions a given UE is associated to which BSs in the uplink and/or downlink.·Designing efficient methods for cooperation and coordination among multiple tiers: Cooperation and coordination among different tiers will be a key requirement to mitigate interference in 5G networks. Cooperation between the macrocell and small cells was proposed for LTE Rel-12 in the context of soft cell, where the UEs are allowed to have dual connectivity by simultaneously connecting to the macrocell and the small cell for uplink and downlink communications or vice versa [3]. As has been mentioned before in the context of asymmetry of transmission power in uplink and downlink, a UE may experience the highest downlink power transmission from the macrocell, whereas the highest uplink path gain may be from a nearby small cell. In this case, the UE can associate to the macrocell in the downlink and to the small cell in the uplink. CoMP schemes based on cooperation among BSs in different tiers (e.g., cooperation between macrocells and small cells) can be developed to mitigate interference in the network. Such schemes need to be adaptive and consider user locations as well as channel conditions to maximize the spectral and energy efficiency of the network. This cooperation however, requires tight integration of low power nodes into the network through the use of reliable, fast andlow latency backhaul connections which will be a major technical issue for upcoming multi-tier 5G networks. In the remaining of this article, we will focus on the review of existing power control and cell association strategies to demonstrate their limitations for interference management in 5G multi-tier prioritized cellular networks (i.e., where users in different tiers have different priorities depending on the location, application requirements and so on). Design guidelines will then be provided to overcome these limitations. Note that issues such as channel scheduling in frequency domain, timedomain interference coordination techniques (e.g., based on almost blank subframes), coordinated multi-point transmission, and spatial domain techniques (e.g., based on smart antenna techniques) are not considered in this article.IV. DISTRIBUTED CELL ASSOCIATION AND POWERCONTROL SCHEMES: CURRENT STATE OF THE ARTA. Distributed Cell Association SchemesThe state-of-the-art cell association schemes that are currently under investigation formulti-tier cellular networks are reviewed and their limitations are explained below.·Reference Signal Received Power (RSRP)-based scheme [5]: A user is associated with the BS whose signal is received with the largest average strength. A variant of RSRP, i.e., Reference Signal Received Quality (RSRQ) is also used for cell selection in LTE single-tier networks which is similar to the signal-to-interference (SIR)-based cell selection where a user selects a BS communicating with which gives the highest SIR. In single-tier networks with uniform traffic, such a criterion may maximize the network throughput. However, due to varying transmit powers of different BSs in the downlink of multi-tier networks, such cell association policies can create a huge traffic load imbalance. This phenomenon leads to overloading of high power tiers while leaving low power tiers underutilized.·Bias-based Cell Range Expansion (CRE) [6]: The idea of CRE has been emerged as a remedy to the problem of load imbalance in the downlink. It aims to increase the downlink coverage footprint of low power BSs by adding a positive bias to their signal strengths (i.e., RSRP or RSRQ). Such BSs are referred to as biased BSs. This biasing allows more users to associate with low power or biased BSs and thereby achieve a better cell load balancing. Nevertheless, such off-loaded users may experience unfavorable channel from the biased BSs and strong interference from the unbiased high-power BSs. The trade-off between cell load balancing and system throughput therefore strictly depends on the selected bias values which need to be optimized in order to maximize the system utility. In this context, a baseline approach in LTE-Advanced is to ―orthogonalize‖ the transmissions of the biased and unbiased BSs in time/frequency domain such that an interference-free zone is created.·Association based on Almost Blank Sub-frame (ABS) ratio [7]: The ABS technique uses time domain orthogonalization in which specific sub-frames are left blank by the unbiased BS and off-loaded users are scheduled within these sub-frames to avoid inter-tier interference. This improves the overall throughput of the off-loaded users by sacrificing the time sub-frames and throughput of the unbiased BS. The larger bias values result in higher degree of offloading and thus require more blank subframes to protect the offloaded users. Given a specific number of ABSs or the ratio of blank over total number of sub-frames (i.e., ABS ratio) that ensures the minimum throughput of the unbiased BSs, this criterion allows a user to select a cell with maximum ABS ratio and may even associate with the unbiased BS if ABS ratio decreases significantly. A qualitative comparison amongthese cell association schemes is given in Table I. The specific key terms used in Table I are defined as follows: channel-aware schemes depend on the knowledge of instantaneous channel and transmit power at the receiver. The interference-aware schemes depend on the knowledge of instantaneous interference at the receiver. The load-aware schemes depend on the traffic load information (e.g., number of users). The resource-aware schemes require the resource allocation information (i.e., the chance of getting a channel or the proportion of resources available in a cell). The priority-aware schemes require the information regarding the priority of different tiers and allow a protection to HPUEs. All of the above mentioned schemes are independent, distributed, and can be incorporated with any type of power control scheme. Although simple and tractable, the standard cell association schemes, i.e., RSRP, RSRQ, and CRE are unable to guarantee the optimum performance in multi-tier networks unless critical parameters, such as bias values, transmit power of the users in the uplink and BSs in the downlink, resource partitioning, etc. are optimized.B. Distributed Power Control SchemesFrom a user’s point of view, the objective of power control is to support a user with its minimum acceptable throughput, whereas from a system’s point of view it is t o maximize the aggregate throughput. In the former case, it is required to compensate for the near-far effect by allocating higher power levels to users with poor channels as compared to UEs with good channels. In the latter case, high power levels are allocated to users with best channels and very low (even zero) power levels are allocated to others. The aggregate transmit power, the outage ratio, and the aggregate throughput (i.e., the sum of achievable rates by the UEs) are the most important measures to compare the performance of different power control schemes. The outage ratio of a particular tier can be expressed as the ratio of the number of UEs supported by a tier with their minimum target SIRs and the total number of UEs in that tier. Numerous power control schemes have been proposed in the literature for single-tier cellular wireless networks. According to the corresponding objective functions and assumptions, the schemes can be classified into the following four types.·Target-SIR-tracking power control (TPC) [8]: In the TPC, each UE tracks its own predefined fixed target-SIR. The TPC enables the UEs to achieve their fixed target-TABLE IQUALITATIVE COMPARISON OF EXISTING CELL ASSOCIATION SCHEMESFOR MULTI-TIER NETWORKSSIRs at minimal aggregate transmit power, assuming thatthe target-SIRs are feasible. However, when the system is infeasible, all non-supported UEs (those who cannot obtain their target-SIRs) transmit at their maximum power, which causes unnecessary power consumption and interference to other users, and therefore, increases the number of non-supported UEs.·TPC with gradual removal (TPC-GR) [9], [10], and [11]:To decrease the outage ra -tio of the TPC in an infeasiblesystem, a number of TPC-GR algorithms were proposedin which non-supported users reduce their transmit power[10] or are gradually removed [9], [11].·Opportunistic power control (OPC) [12]: From the system’s point of view, OPC allocates high power levels to users with good channels (experiencing high path-gains and low interference levels) and very low power to users with poor channels. In this algorithm, a small difference in path-gains between two users may lead to a large difference in their actual throughputs [12]. OPC improves the system performance at the cost of reduced fairness among users.·Dynamic-SIR tracking power control (DTPC) [13]: When the target-SIR requirements for users are feasible, TPC causes users to exactly hit their fixed target-SIRs even if additional resources are still available that can otherwise be used to achieve higher SIRs (and thus better throughputs). Besides, the fixed-target-SIR assignment is suitable only for voice service for which reaching a SIR value higher than the given target value does not affect the service quality significantly. In contrast, for data services, a higher SIR results in a better throughput, which is desirable. The DTPC algorithm was proposed in [13] to address the problem of system throughput maximization subject to a given feasible lower bound for the achieved SIRs of all users in cellular networks. In DTPC, each user dynamically sets its target-SIR by using TPC and OPC in a selective manner. It was shown that when the minimum acceptable target-SIRs are feasible, the actual SIRs received by some users can be dynamically increased (to a value higher than their minimum acceptabletarget-SIRs) in a distributed manner so far as the required resources are available and the system remains feasible (meaning that reaching the minimum target-SIRs for the remaining users are guaranteed). This enhances the system throughput (at the cost of higher power consumption) as compared to TPC. The aforementioned state-of-the-art distributed power control schemes for satisfying various objectives in single-tier wireless cellular networks are unable to address the interference management problem in prioritized 5G multi-tier networks. This is due to the fact that they do not guarantee that the total interference caused by the LPUEs to the HPUEs remain within tolerable limits, which can lead to the SIR outage of some HPUEs. Thus there is a need to modify the existing schemes such that LPUEs track their objectives while limiting their transmit power to maintain a given interference threshold at HPUEs. A qualitative comparison among various state-of-the-art power control problems with different objectives and constraints and their corresponding existing distributed solutions are shown in Table II. This table also shows how these schemes can be modified and generalized for designing CAPC schemes for prioritized 5G multi-tier networks.C. Joint Cell Association and Power Control SchemesA very few work in the literature have considered the problem of distributed CAPC jointly (e.g., [14]) with guaranteed convergence. For single-tier networks, a distributed framework for uplink was developed [14], which performs cell selection based on the effective-interference (ratio of instantaneous interference to channel gain) at the BSs and minimizes the aggregate uplink transmit power while attaining users’ desire d SIR targets. Following this approach, a unified distributed algorithm was designed in [15] for two-tier networks. The cell association is based on the effective-interference metric and is integrated with a hybrid power control (HPC) scheme which is a combination of TPC and OPC power control algorithms.Although the above frameworks are distributed and optimal/ suboptimal with guaranteed convergence in conventional networks, they may not be directly compatible to the 5G multi-tier networks. The interference dynamics in multi-tier networks depends significantly on the channel access protocols (or scheduling), QoS requirements and priorities at different tiers. Thus, the existing CAPC optimization problems should be modified to include various types of cell selection methods (some examples are provided in Table I) and power control methods with different objectives and interference constraints (e.g., interference constraints for macro cell UEs, picocell UEs, or D2Dreceiver UEs). A qualitative comparison among the existing CAPC schemes along with the open research areas are highlighted in Table II. A discussion on how these open problems can be addressed is provided in the next section.V. DESIGN GUIDELINES FOR DISTRIBUTED CAPCSCHEMES IN 5G MULTI-TIER NETWORKSInterference management in 5G networks requires efficient distributed CAPC schemes such that each user can possibly connect simultaneously to multiple BSs (can be different for uplink and downlink), while achieving load balancing in different cells and guaranteeing interference protection for the HPUEs. In what follows, we provide a number of suggestions to modify the existing schemes.A. Prioritized Power ControlTo guarantee interference protection for HPUEs, a possible strategy is to modify the existing power control schemes listed in the first column of Table II such that the LPUEs limit their transmit power to keep the interference caused to the HPUEs below a predefined threshold, while tracking their own objectives. In other words, as long as the HPUEs are protected against existence of LPUEs, the LPUEs could employ an existing distributed power control algorithm to satisfy a predefined goal. This offers some fruitful direction for future research and investigation as stated in Table II. To address these open problems in a distributed manner, the existing schemes should be modified so that the LPUEs in addition to setting their transmit power for tracking their objectives, limit their transmit power to keep their interference on receivers of HPUEs below a given threshold. This could be implemented by sending a command from HPUEs to its nearby LPUEs (like a closed-loop power control command used to address the near-far problem), when the interference caused by the LPUEs to the HPUEs exceeds a given threshold. We refer to this type of power control as prioritized power control. Note that the notion of priority and thus the need of prioritized power control exists implicitly in different scenarios of 5G networks, as briefly discussed in Section II. Along this line, some modified power control optimization problems are formulated for 5G multi-tier networks in second column of Table II.To compare the performance of existing distributed power control algorithms, let us consider a prioritized multi-tier cellular wireless network where a high-priority tier consisting of 3×3 macro cells, each of which covers an area of 1000 m×1000 m, coexists with a low-priority tier consisting of n small-cells per each high-priority macro cell, each。
09届本科毕业设计(论文)外文文献翻译学 院： 物理与电子工程学院专 业： 光电信息工程姓 名： 徐 驰学 号： Y05209222 外文出处： Surface & Coatings Technology214（2013）131-137附 件： 1.外文资料翻译译文；2.外文原文。
(用外文写)附件1：外文资料翻译译文气体温度通过PECVD沉积对Si：H薄膜的结构和光电性能的影响摘要气体温度的影响（TG）在等离子体增强化学气相沉积法（PECVD）生长的薄膜的结构和光电特性：H薄膜已使用多种表征技术研究。
气体的温度被确定为制备工艺的优化、结构和光电薄膜的性能改进的一个重要参数。
薄膜的结构性能进行了研究使用原子力显微镜（AFM），傅立叶变换红外光谱（FTIR），拉曼光谱，和电子自旋共振（ESR）。
此外，光谱椭偏仪（SE），在紫外线–可见光区域的光传输的测量和电气测量被用来研究的薄膜的光学和电学性能。
它被发现在Tg的变化可以修改的表面粗糙度，非晶网络秩序，氢键模式和薄膜的密度，并最终提高光学和电学性能。
1.介绍等离子体增强化学气相沉积法（PECVD）是氢化非晶硅薄膜制备一种技术，具有广泛的实际应用的重要材料。
它是用于太阳能电池生产，在夜视系统红外探测器，和薄膜晶体管的平板显示装置。
所有这些应用都是基于其良好的电气和光学特性以及与半导体技术兼容。
然而，根据a-Si的性质，PECVD制备H薄膜需要敏感的沉积条件，如衬底温度，功率密度，气体流量和压力。
许多努力已经花在制备高品质的薄膜具有较低的缺陷密度和较高的结构稳定性的H薄膜。
众所周知，衬底温度的强烈影响的自由基扩散的生长表面上，从而导致这些自由基更容易定位在最佳生长区。
因此，衬底温度一直是研究最多的沉积参数。
至于温度参数在PECVD工艺而言，除了衬底温度，气体温度（Tg）美联储在PECVD反应室在辉光放电是定制的a-Si的性能参数：H薄膜的新工艺。
广东工业大学华立学院本科毕业设计（论文）外文参考文献译文及原文系部城建学部专业土木工程年级 2011级班级名称 11土木工程9班学号 23031109000学生姓名刘林指导教师卢集富2015 年5 月目录一、项目成本管理与控制 0二、Project Budget Monitor and Control (1)三、施工阶段承包商在控制施工成本方面所扮演的作用 (2)四、The Contractor’s Role in Building Cost Reduction After Design (4)一、外文文献译文（1）项目成本管理与控制随着市场竞争的激烈性越来越大,在每一个项目中，进行成本控制越发重要。
本文论述了在施工阶段,项目经理如何成功地控制项目预算成本。
本文讨论了很多方法。
它表明，要取得成功，项目经理必须关注这些成功的方法.1。
简介调查显示,大多数项目会碰到超出预算的问……功控制预算成本.2.项目控制和监测的概念和目的Erel and Raz (2000）指出项目控制周期包括测量成……原因以及决定纠偏措施并采取行动。
监控的目的就是纠偏措施的。
.。
标范围内。
3.建立一个有效的控制体系为了实现预算成本的目标，项目管理者需要建立一……被监测和控制是非常有帮助的。
项目成功与良好的沟通密。
决（ Diallo and Thuillier， 2005）.4.成本费用的检测和控制4.1对检测的优先顺序进行排序在施工阶段，很多施工活动是基于原来的计……用完了。
第四,项目管理者应该检测高风险活动，高风险活动最有。
..重要（Cotterell and Hughes, 1995)。
4.2成本控制的方法一个项目的主要费用包括员工成本、材料成本以及工期延误的成本。
为了控制这些成本费用，项目管理者首先应该建立一个成本控制系统：a)为财务数据的管理和分析工作落实责任人员b)确保按照项目的结构来合理分配所有的……它的变化-—在成本控制线上准确地记录所有恰..。
软件工程毕业论文文献翻译中英文对照学生毕业设计(论文)外文译文学生姓名: 学号专业名称:软件工程译文标题(中英文):Qt Creator白皮书(Qt Creator Whitepaper)译文出处:Qt network 指导教师审阅签名: 外文译文正文:Qt Creator白皮书Qt Creator是一个完整的集成开发环境(IDE)，用于创建Qt应用程序框架的应用。
Qt是专为应用程序和用户界面，一次开发和部署跨多个桌面和移动操作系统。
本文提供了一个推出的Qt Creator和提供Qt开发人员在应用开发生命周期的特点。
Qt Creator的简介Qt Creator的主要优点之一是它允许一个开发团队共享一个项目不同的开发平台(微软Windows?的Mac OS X?和Linux?)共同为开发和调试工具。
Qt Creator的主要目标是满足Qt开发人员正在寻找简单，易用性，生产力，可扩展性和开放的发展需要，而旨在降低进入新来乍到Qt的屏障。
Qt Creator 的主要功能，让开发商完成以下任务: , 快速，轻松地开始使用Qt应用开发项目向导，快速访问最近的项目和会议。
, 设计Qt物件为基础的应用与集成的编辑器的用户界面，Qt Designer中。
, 开发与应用的先进的C + +代码编辑器，提供新的强大的功能完成的代码片段，重构代码，查看文件的轮廓(即，象征着一个文件层次)。
, 建立，运行和部署Qt项目，目标多个桌面和移动平台，如微软Windows，Mac OS X中，Linux的，诺基亚的MeeGo，和Maemo。
, GNU和CDB使用Qt类结构的认识，增加了图形用户界面的调试器的调试。
, 使用代码分析工具，以检查你的应用程序中的内存管理问题。
, 应用程序部署到移动设备的MeeGo，为Symbian和Maemo设备创建应用程序安装包，可以在Ovi商店和其他渠道发布的。
, 轻松地访问信息集成的上下文敏感的Qt帮助系统。
毕业设计（论文）外文资料翻译及原文（2012届）题目电话机三维造型与注塑模具设计指导教师院系工学院班级学号姓名二〇一一年十二月六日【译文一】塑料注塑模具并行设计Assist.Prof.Dr. A. Y AYLA /Prof.Dr. Paş a YAYLA摘要塑料制品制造业近年迅速成长。
其中最受欢迎的制作过程是注塑塑料零件。
注塑模具的设计对产品质量和效率的产品加工非常重要。
模具公司想保持竞争优势,就必须缩短模具设计和制造的周期。
模具是工业的一个重要支持行业，在产品开发过程中作为一个重要产品设计师和制造商之间的联系。
产品开发经历了从传统的串行开发设计制造到有组织的并行设计和制造过程中,被认为是在非常早期的阶段的设计。
并行工程的概念(CE)不再是新的,但它仍然是适用于当今的相关环境。
团队合作精神、管理参与、总体设计过程和整合IT工具仍然是并行工程的本质。
CE过程的应用设计的注射过程包括同时考虑塑件设计、模具设计和注塑成型机的选择、生产调度和成本中尽快设计阶段。
介绍了注射模具的基本结构设计。
在该系统的基础上,模具设计公司分析注塑模具设计过程。
该注射模设计系统包括模具设计过程及模具知识管理。
最后的原则概述了塑料注射模并行工程过程并对其原理应用到设计。
关键词:塑料注射模设计、并行工程、计算机辅助工程、成型条件、塑料注塑、流动模拟1、简介注塑模具总是昂贵的,不幸的是没有模具就不可能生产模具制品。
每一个模具制造商都有他/她自己的方法来设计模具,有许多不同的设计与建造模具。
当然最关键的参数之一,要考虑到模具设计阶段是大量的计算、注射的方法,浇注的的方法、研究注射成型机容量和特点。
模具的成本、模具的质量和制件质量是分不开的在针对今天的计算机辅助充型模拟软件包能准确地预测任何部分充填模式环境中。
这允许快速模拟实习,帮助找到模具的最佳位置。
工程师可以在电脑上执行成型试验前完成零件设计。
工程师可以预测过程系统设计和加工窗口,并能获得信息累积所带来的影响,如部分过程变量影响性能、成本、外观等。
毕业设计（论文）外文原文及译文一、外文原文MCUA microcontroller (or MCU) is a computer-on-a-chip. It is a type of microcontroller emphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purpose microprocessor (the kind used in a PC).With the development of technology and control systems in a wide range of applications, as well as equipment to small and intelligent development, as one of the single-chip high-tech for its small size, powerful, low cost, and other advantages of the use of flexible, show a strong vitality. It is generally better compared to the integrated circuit of anti-interference ability, the environmental temperature and humidity have better adaptability, can be stable under the conditions in the industrial. And single-chip widely used in a variety of instruments and meters, so that intelligent instrumentation and improves their measurement speed and measurement accuracy, to strengthen control functions. In short，with the advent of the information age, traditional single- chip inherent structural weaknesses, so that it show a lot of drawbacks. The speed, scale, performance indicators, such as users increasingly difficult to meet the needs of the development of single-chip chipset, upgrades are faced with new challenges.The Description of AT89S52The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of In-System Programmable Flash memory. The device is manufactured using Atmel's high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with In-System Programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.The AT89S52 provides the following standard features: 8K bytes ofFlash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset.Features• Compatible with MCS-51® Products• 8K Bytes of In-System Programmable (ISP) Flash Memory– Endurance: 1000 Write/Erase Cycles• 4.0V to 5.5V Operating Range• Fully Static Operation: 0 Hz to 33 MHz• Three-level Program Memory Lock• 256 x 8-bit Internal RAM• 32 Programmable I/O Lines• Three 16-bit Timer/Counters• Eight Interrupt Sources• Full Duplex UART Serial Channel• Low-power Idle and Power-down Modes• Interrupt Recovery from Power-down Mode• Watchdog Timer• Dual Data Pointer• Power-off FlagPin DescriptionVCCSupply voltage.GNDGround.Port 0Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs.Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pullups.Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pullups are required during program verification.Port 1Port 1 is an 8-bit bidirectional I/O port with internal pullups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2Port 2 is an 8-bit bidirectional I/O port with internal pullups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bidirectional I/O port with internal pullups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89S52, as shown in the following table.Port 3 also receives some control signals for Flash programming and verification.RSTReset input. A high on this pin for two machine cycles while the oscillator is running resets the device. This pin drives High for 96 oscillator periods after the Watchdog times out. The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit DISRTO, the RESET HIGH out feature is enabled.ALE/PROGAddress Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSENProgram Store Enable (PSEN) is the read strobe to external program memory. When the AT89S52 is executing code from external program memory, PSENis activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit.XTAL2Output from the inverting oscillator amplifier.Special Function RegistersNote that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general return random data, and write accesses will have an indeterminate effect.User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that case, the reset or inactive values of the new bits will always be 0.Timer 2 Registers:Control and status bits are contained in registers T2CON and T2MOD for Timer 2. The register pair (RCAP2H, RCAP2L) are the Capture/Reload registers for Timer 2 in 16-bit capture mode or 16-bit auto-reload mode.Interrupt Registers:The individual interrupt enable bits are in the IE register. Two priorities can be set for each of the six interrupt sources in the IP register.Dual Data Pointer Registers: To facilitate accessing both internal and external data memory, two banks of 16-bit Data Pointer Registers areprovided: DP0 at SFR address locations 82H-83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1. The user should always initialize the DPS bit to the appropriate value before accessing the respective Data Pointer Register.Power Off Flag:The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF is set to “1” during power up. It can be set and rest under software control and is not affected by reset.Memory OrganizationMCS-51 devices have a separate address space for Program and Data Memory. Up to 64K bytes each of external Program and Data Memory can be addressed.Program MemoryIf the EA pin is connected to GND, all program fetches are directed to external memory. On the AT89S52, if EA is connected to VCC, program fetches to addresses 0000H through 1FFFH are directed to internal memory and fetches to addresses 2000H through FFFFH are to external memory.Data MemoryThe AT89S52 implements 256 bytes of on-chip RAM. The upper 128 bytes occupy a parallel address space to the Special Function Registers. This means that the upper 128 bytes have the same addresses as the SFR space but are physically separate from SFR space.When an instruction accesses an internal location above address 7FH, the address mode used in the instruction specifies whether the CPU accesses the upper 128 bytes of RAM or the SFR space. Instructions which use direct addressing access of the SFR space. For example, the following direct addressing instruction accesses the SFR at location 0A0H (which is P2).MOV 0A0H, #dataInstructions that use indirect addressing access the upper 128 bytes of RAM. For example, the following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H).MOV @R0, #dataNote that stack operations are examples of indirect addressing, so the upper 128 bytes of data RAM are available as stack space.Timer 0 and 1Timer 0 and Timer 1 in the AT89S52 operate the same way as Timer 0 and Timer 1 in the AT89C51 and AT89C52.Timer 2Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter. The type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 2). Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate generator. The modes are selected by bits in T2CON.Timer 2 consists of two 8-bit registers, TH2 and TL2. In the Timer function, the TL2 register is incremented every machine cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the oscillator frequency.In the Counter function, the register is incremented in response to a1-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count is incremented. The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are required to recognize a 1-to-0 transition, the maximum count rate is 1/24 of the oscillator frequency. To ensure that a given level is sampled at least once before it changes, the level should be held for at least one full machine cycle.InterruptsThe AT89S52 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown in Figure 10.Each of these interrupt sources can be individually enabled or disabledby setting or clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all interrupts at once.Note that Table 5 shows that bit position IE.6 is unimplemented. In the AT89S52, bit position IE.5 is also unimplemented. User software should not write 1s to these bit positions, since they may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the service routine is vectored to. In fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software.The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows.二、译文单片机单片机即微型计算机，是把中央处理器、存储器、定时/计数器、输入输出接口都集成在一块集成电路芯片上的微型计算机。
广东工业大学华立学院本科毕业设计（论文）外文参考文献译文及原文系部经济学部专业经济学年级 2007级班级名称 07经济学6班学号 16020706001学生姓名张瑜琴指导教师陈锶2011 年05月目录1挑战：小额贷款中的进入和商业银行的长期承诺 (1)2什么商业银行带给小额贷款和什么把他们留在外 (2)3 商业银行的四个模型进入小额贷款之内 (4)3.1内在的单位 (4)3.2财务子公司 (5)3.3策略的同盟 (5)3.4服务公司模型 (6)4 合法的形式和操作的结构比较 (8)5 服务的个案研究公司模型：厄瓜多尔和Haiti5 (9)1 挑战：小额贷款中的进入和商业银行的长期承诺商业银行已经是逐渐重要的运动员在拉丁美洲中的小额贷款服务的发展2到小额贷款市场是小额贷款的好消息客户因为银行能提供他们一完整类型的财务的服务，包括信用，储蓄和以费用为基础的服务。
整体而言，它也对小额贷款重要，因为与他们广泛的身体、财务的和人类。
如果商业银行变成重的运动员在小额贷款，他们能提供非常强烈的竞争到传统的小额贷款机构。
资源，银行能廉宜地发射而且扩张小额贷款服务rela tively。
如果商业广告银行在小额贷款中成为严重的运动员，他们能提出非常强烈的竞争给传统的小额贷款机构。
然而，小额贷款社区里面有知觉哪一商业银行进入进入小额贷款将会是短命或浅的。
举例来说，有知觉哪一商业银行首先可能不搬进小额贷款因为时候建立小额贷款操作到一个有利润的水平超过银行的标准投资时间地平线。
或，在进入小额贷款，银行之后可能移动在－上面藉由增加贷款数量销售取利润最大值－或者更坏的事，退出如果他们是不满意与小额贷款的收益性的水平。
这些知觉已经被特性加燃料商业银行的情形进入小额贷款和后来的出口之内。
在最极端的，一些开业者已经甚至宣布，”降低尺度死！”而且抛弃了与主意合作的商业银行。
在最 signific 看得到的地方，蚂蚁利益商业银行可能带给小额贷款，国际的ACCION 发展发射而且扩张的和一些商业银行的关系小额贷款操作。
毕业设计外文资料翻译学院：信息科学与工程学院专业：软件工程姓名： XXXXX学号： XXXXXXXXX外文出处： Think In Java (用外文写)附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂，而且极易出错。
程序员必须掌握与网络有关的大量细节，有时甚至要对硬件有深刻的认识。
一般地，我们需要理解连网协议中不同的“层”（Layer）。
而且对于每个连网库，一般都包含了数量众多的函数，分别涉及信息块的连接、打包和拆包；这些块的来回运输；以及握手等等。
这是一项令人痛苦的工作。
但是，连网本身的概念并不是很难。
我们想获得位于其他地方某台机器上的信息，并把它们移到这儿；或者相反。
这与读写文件非常相似，只是文件存在于远程机器上，而且远程机器有权决定如何处理我们请求或者发送的数据。
Java最出色的一个地方就是它的“无痛苦连网”概念。
有关连网的基层细节已被尽可能地提取出去，并隐藏在JVM以及Java的本机安装系统里进行控制。
我们使用的编程模型是一个文件的模型；事实上，网络连接（一个“套接字”）已被封装到系统对象里，所以可象对其他数据流那样采用同样的方法调用。
除此以外，在我们处理另一个连网问题——同时控制多个网络连接——的时候，Java内建的多线程机制也是十分方便的。
本章将用一系列易懂的例子解释Java的连网支持。
15.1 机器的标识当然，为了分辨来自别处的一台机器，以及为了保证自己连接的是希望的那台机器，必须有一种机制能独一无二地标识出网络内的每台机器。
早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。
但Java面向的是整个因特网，这要求用一种机制对来自世界各地的机器进行标识。
为达到这个目的，我们采用了IP（互联网地址）的概念。
IP以两种形式存在着：(1) 大家最熟悉的DNS（域名服务）形式。
我自己的域名是。
所以假定我在自己的域内有一台名为Opus的计算机，它的域名就可以是。
毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土结构设计文献、资料英文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文参考资料及译文译文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and thestress of steel bars will increase . When the steel approaches the yielding stress ƒy , thedeflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large cross sections .As concrete has high modulus of elasticity, reinforced concrete structures are usuallystiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(b)Reinfoced concrete beam(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures are cheaper.(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforcedconcrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressed concrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid。
Hacking tricks toward security on network environments Tzer-Shyong Chen1, Fuh-Gwo Jeng 2, and Yu-Chia Liu 11 Department of Information Management, Tunghai University, Taiwan2 Department of Applied Mathematics, National Chiayi University, TaiwanE-Mail:****************.edu.twAbstractMounting popularity of the Internet has led to the birth of Instant Messaging, an up-and-coming form of Internet communication. Instant Messaging is very popular with businesses and individuals since it has instant communication ability. As a result, Internet security has become a pressing and important topic for discussion. Therefore, in recent years, a lot of attention has been drawn towards Internet security and the various attacks carried out by hackers over the Internet. People today often handle affairs via the Internet. For instance, instead of the conventional letter, they communicate with others by e-mails; they chat with friends through an instant messenger; find information by browsing websites instead of going to the library; perform e-commerce transactions through the Internet, etc. Although the convenience of the Internet makes our life easier, it is also a threat to Internet security. For instance, a business email intercepted during its transmission may let slip business confidentiality; file transfers via instant messengers may also be intercepted, and then implanted with backdoor malwares; conversations via instant messengers could be eavesdropped. Furthermore, ID and password theft may lose us money when using Internet bank service. Attackers on the Internet use hacking tricks to damage systems while users are connected to the Internet. These threats along with possible careless disclosure of business information make Instant Messaging a very unsafe method of communication for businesses. The paper divides hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing or fraud via e-mails. (3) Fake Websites. Keywords:Hacking tricks, Trojan programs, Phishing, Firewall, Intrusion detection system.1. IntroductionIncreasingly more people are using instant messengers such as MSN Messenger, Yahoo! Messenger, ICQ, etc as the media of communication. These instant messengers transmit alphanumeric message as well as permit file sharing. During transfer, a file may be intercepted by a hacker and implanted with backdoor malware. Moreover, the e-mails users receive every day may include Spam, advertisements, and fraudulent mail intended to trick uninformed users. Fake websites too are prevalent. Websites which we often visit could be counterfeited by imitating the interface and the URL of the original, tricking users. The paper classifies hacking tricks into three categories which are explained in the following sections.2. Hacking TricksThe paper divides hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing (3) Fake Websites.2.1 Trojan programs that share files via instant messengerInstant messaging allows file-sharing on a computer [9]. All present popular instant messengers have file sharing abilities, or allow users to have the above functionality by installing patches or plug-ins; this is also a major threat to present information security. These communication softwares also makeit difficult for existing hack prevention methods to prevent and control information security. Therefore, we shall discuss how to control the flow of instant messages and how to identify dangerous user behavior.Hackers use instant communication capability to plant Trojan program into an unsuspected program; the planted program is a kind of remotely controlled hacking tool that can conceal itself and is unauthorized. The Trojan program is unknowingly executed, controlling the infected computer; it can read, delete, move and execute any file on the computer. The advantages of a hacker replacing remotely installed backdoor Trojan programs [1] with instant messengers to access files are:When the victim gets online, the hacker will be informed. Thus, a hacker can track and access the infected computer, and incessantly steal user information.A hacker need not open a new port to perform transmissions; he can perform his operations through the already opened instant messenger port.Even if a computer uses dynamic IP addresses, its screen name doesn’t change.Certain Trojan programs are designed especially for instant messengers. These Trojans can change group settings and share all files on the hard disk of the infected computer. They can also destroy or modify data, causing data disarray. This kind of program allows a hacker access to all files on an infected computer, and thus poses a great threat to users. The Trojan program takes up a large amount of the resources of the computer causing it to become very slow and often crashes without a reason.Trojan programs that access a user computer through an instant messenger are probably harder to detect than classic Trojan horse programs. Although classic Trojan intrudes a computer by opening a listening or outgoing port which is used to connect toa remote computer, a desktop firewall can effectively block such Trojans. Alternatively, since it is very difficult for the server’s firewall to spot intrusion by controlling an instant messenger’s flow, it is extremely susceptible to intrusion.Present Trojan programs have already successfully implemented instant messengers. Some Trojan programs are Backdoor Trojan, AIMVision, and Backdoor. Sparta.C. Backdoor Trojans use ICQ pager to send messages to its writer. AIMVision steals AIM related information stored in the Windows registry, enabling a hacker to setup an AIM user id. Backdoor. Sparta.C uses ICQ to communicate with its writer and opens a port on an infected host and send its IP Address to the hacker, and at the same time attempts to terminate the antivirus program or firewall of the host.2.1.1 Hijacking and ImpersonationThere are various ways through which a hacker can impersonate other users [7]. The most commonly used method is eavesdropping on unsuspecting users to retrieve user accounts, passwords and other user related information.The theft of user account number and related information is a very serious problem in any instant messenger. For instance, a hacker after stealing a user’s information impersonate the user; the user’s contacts not knowing that the user’s account has been hacked believe that the person they’re talking to is the user, and are persuaded to execute certain programs or reveal confidential information. Hence, theft of user identity not only endangers a user but also surrounding users. Guarding against Internet security problems is presently the focus of future research; because without good protection, a computer can be easily attacked, causing major losses.Hackers wishing to obtain user accounts may do so with the help of Trojans designed to steal passwords. If an instant messenger client stores his/her password on his/her computer, then a hacker can send a Trojan program to the unsuspecting user. When the user executes the program, the program shall search for the user’s password and send it to the hacker. There are several ways through which a Trojan program can send messages back to the hacker. The methods include instant messenger, IRC, e-mails, etc.Current four most popular instant messengers are AIM, Yahoo! Messenger, ICQ, and MSN Messenger, none of which encrypts its flow. Therefore, a hackercan use a man-in-the-middle attack to hijack a connection, then impersonate the hijacked user and participate in a chat-session. Although difficult, a hacker can use the man-in-the-middle attack to hijack the connection entirely. For example, a user may receive an offline message that resembles that sent by the server, but this message could have been sent by the hacker. All at once, the user could also get disconnected to the server. Furthermore, hackers may also use a Denial of Service (DoS) tool or other unrelated exploits to break the user’s connection. However, the server keeps the connection open, and does not know that the user has been disconnected; thus allowing the hacker to impersonate the user. Moreover, since the data flow is unencrypted and unauthenticated, a hacker can use man-in-the-middle attacks that are similar to that of ARP fraud to achieve its purpose.2.1.2 Denial of Service (DoS)There are many ways through which a hacker can launch a denial of service (DoS) attack [2] on an instant messenger user. A Partial DoS attack will cause a user end to hang, or use up a large portion of CPU resources causing the system to become unstable.Another commonly seen attack is the flooding of messages to a particular user. Most instant messengers allow the blocking of a particular user to prevent flood attacks. However, a hacker can use tools that allow him to log in using several different identities at the same time, or automatically create a large number of new user ids, thus enabling a flood attack. Once a flood attack begins, even if the user realizes that his/her computer has been infected, the computer will not be able to respond. Thus, the problem cannot be solved by putting a hacker’s user id on the ignore list of your instant messenger.A DoS attack on an instant messenger client is only a common hacking tool. The difficulty of taking precautions against it could turn this hacking tool into dangerous DoS type attacks. Moreover, some hacking tools do not just cause an instant messenger client to hang, but also cause the user end to consume large amount of CPU time, causing the computer to crash.2.1.3 Information DisclosureRetrieving system information through instant messenger users is currently the most commonly used hacking tool [4]. It can effortlessly collect user network information like, current IP, port, etc. IP address retriever is an example. IP address retrievers can be used to many purposes; for instance, a Trojan when integrated with an IP address retriever allows a hacker to receive all information related to the infected computer’s IP address as soon as the infected computer connects to the internet. Therefore, even if the user uses a dynamic IP address, hackers can still retrieve the IP address.IP address retrievers and other similar tools can also be used by hackers to send data and Trojans to unsuspecting users. Hackers may also persuade unsuspecting users to execute files through social engineering or other unrelated exploits. These files when executed search for information on the user’s computer and sends them back to the hacker through the instant messenger network.Different Trojan programs were designed for different instant messaging clients. For example, with a user accounts and password stealing Trojans a hacker can have full control of the account once the user logs out. The hacker can thus perform various tasks like changing the password and sending the Trojan program to all of the user’s contacts.Moreover, Trojans is not the only way through which a hacker can cause information disclosure. Since data sent through instant messengers are unencrypted, hackers can sniff and monitor entire instant messaging transmissions. Suppose an employee of an enterprise sends confidential information of the enterprise through the instant messenger; a hacker monitoring the instant messaging session can retrieve the data sent by the enterprise employee. Thus, we must face up to the severity of the problem.2.2 PhishingThe word “Phishing” first appeared in 1996. It is a variant of ‘fishing’, and formed by replacing the ‘f’ in ‘fishing’ with ‘ph’ from phone. It means tricking users of their money through e-mails.Based on the statistics of the Internet Crime Complaint Center, loss due to internet scam was as high as $1.256 million USD in 2004. The Internet Crime Complaint Center has listed the above Nigerian internet scam as one of the ten major internet scams.Based on the latest report of Anti-Phishing Working Group (APWG) [8], there has been a 28% growth of Phishing scams in the past 4 months, mostly in the US and in Asia. Through social engineering and Trojans, it is very difficult for a common user to detect the infection.To avoid exploitation of your compassion, the following should be noted:(1)When you need to enter confidentialinformation, first make sure that theinformation is entered via an entirely secureand official webpage. There are two ways todetermine the security of the webpage:a.The address displayed on the browserbegins with https://, and not http://. Payattention to if the letter ‘s’ exists.b.There is a security lock sign on the lowerright corner of the webpage, and whenyour mouse points to the sign, a securitycertification sign shall appear.(2)Consider installing a browser security softwarelike SpoofStick which can detect fake websites.(3)If you suspect the received e-mail is a Phishinge-mail, do not open attachments attached to theemail. Opening an unknown attachment couldinstall malicious programs onto your computer.(4)Do not click on links attached to your emails. Itis always safer to visit the website through theofficial link or to first confirm the authenticityof the link. Never follow or click on suspiciouslinks in an e-mail. It is advisable to enter theURL at the address bar of the web browser,and not follow the given link.Generally speaking, Phishing [3] [5] is a method that exploits people’s sympathy in the form of aid-seeking e-mails; the e-mail act as bait. These e-mails usually request their readers to visit a link that seemingly links to some charitable organization’s website; but in truth links the readers to a website that will install a Trojan program into the reader’s computer. Therefore, users should not forward unauthenticated charity mails, or click on unfamiliar links in an e-mail. Sometimes, the link could be a very familiar link or an often frequented website, but still, it would be safer if you’d type in the address yourself so as to avoid being linked to a fraudulent website. Phisher deludes people by using similar e-mails mailed by well-known enterprises or banks; these e-mails often asks users to provide personal information, or result in losing their personal rights; they usually contain a counterfeit URL which links to a website where the users can fillin the required information. People are often trapped by phishing due to inattentionBesides, you must also be careful when using a search engine to search for donations and charitable organizations.2.3 Fake WebsitesFake bank websites stealing account numbers and passwords have become increasingly common with the growth of online financial transactions. Hence, when using online banking, we should take precautions like using a secure encrypted customer’s certificate, surf the net following the correct procedure, etc.There are countless kinds of phishing baits, for instance, messages that say data expired, data invalid, please update data, or identity verification intended to steal account ID and matching password. This typeof online scam is difficult for users to identify. As scam methods become finer, e-mails and forged websites created by the impostor resemble their original, and tremendous losses arise from the illegal transactions.The following are methods commonly used by fake websites. First, the scammers create a similar website homepage; then they send out e-mails withenticing messages to attract visitors. They may also use fake links to link internet surfers to their website. Next, the fake website tricks the visitors into entering their personal information, credit card information or online banking account number and passwords. After obtaining a user’s information, the scammers can use the information to drain the bank accounts, shop online or create fake credit cards and other similar crimes. Usually, there will be a quick search option on these fake websites, luring users to enter their account number and password. When a user enters their account number and password, the website will respond with a message stating that the server is under maintenance. Hence, we must observe the following when using online banking:(1)Observe the correct procedure for entering abanking website. Do not use links resultingfrom searches or links on other websites.(2)Online banking certifications are currently themost effective security safeguard measure. (3)Do not easily trust e-mails, phone calls, andshort messages, etc. that asks for your accountnumber and passwords.Phishers often impost a well-known enterprise while sending their e-mails, by changing the sender’s e-mail address to that of the well known enterprise, in order to gain people’s trust. The ‘From’ column of an e-mail is set by the mail software and can be easily changed by the web administrator. Then, the Phisher creates a fake information input website, and send out e-mails containing a link to this fake website to lure e-mail recipients into visiting his fake website.Most Phishers create imitations of well known enterprises websites to lure users into using their fake websites. Even so, a user can easily notice that the URL of the website they’re entering has no relation to the intended enterprise. Hence, Phishers may use different methods to impersonate enterprises and other people. A commonly used method is hiding the URL. This can easily be done with the help of JavaScript.Another way is to exploit the loopholes in an internet browser, for instance, displaying a fake URL in the browser’s address bar. The security loophole causing the address bar of a browser to display a fake URL is a commonly used trick and has often been used in the past. For example, an e-mail in HTML format may hold the URL of a website of a well-known enterprise, but in reality, the link connects to a fake website.The key to successfully use a URL similar to that of the intended website is to trick the visual senses. For example, the sender’s address could be disguised as that of Nikkei BP, and the link set to http://www.nikeibp.co.jp/ which has one k less than the correct URL which is http://www.nikkeibp.co.jp/. The two URLs look very similar, and the difference barely noticeable. Hence people are easily tricked into clicking the link.Besides the above, there are many more scams that exploit the trickery of visual senses. Therefore, you should not easily trust the given sender’s name and a website’s appearance. Never click on unfamiliar and suspicious URLs on a webpage. Also, never enter personal information into a website without careful scrutiny.3. ConclusionsBusiness strategy is the most effective form of defense and also the easiest to carry out. Therefore, they should be the first line of defense, and not last. First, determine if instant messaging is essential in the business; then weigh its pros and cons. Rules and norms must be set on user ends if it is decided that the business cannot do without instant messaging functionality. The end server should be able to support functions like centralized logging and encryption. If not, then strict rules must be drawn, and carried out by the users. Especially, business discussions must not be done over an instant messenger.The paper categorized hacking tricks into three categories: (1) Trojan programs that share files via instant messenger. (2) Phishing (3) Fake Websites. Hacking tricks when successfully carried out could cause considerable loss and damage to users. The first category of hacking tricks can be divided into three types: (1) Hijacking and Impersonation; (2) Denial of Service; (3) Information Disclosure.Acknowledgement:This work was supported by the National Science Council, Taiwan, under contract No. NSC 95-2221-E-029-024.References[1] B. Schneier, “The trojan horse race,”Communications of ACM, Vol. 42, 1999, pp.128.[2] C. L. Schuba, “Analysis of a denial of serviceattack on TCP,” IEEE Security and PrivacyConference, 1997, pp. 208-223.[3] E. Schultz, “Phishing is becoming moresophisticated,” Computer and Security, Vol.24(3), 2005, pp. 184-185.[4]G. Miklau, D. Suciu, “A formal analysis ofinformation disclosure in data exchange,”International Conference on Management ofData, 2004, pp. 575-586.[5]J. Hoyle, “'Phishing' for trouble,” Journal ofthe American Detal Association, Vol. 134(9),2003, pp. 1182-1182.[6]J. Scambray, S. McClure, G. Kurtz, Hackingexposed: network security secrets and solutions,McGraw-Hill, 2001.[7]T. Tsuji and A. Shimizu, “An impersonationattack on one-time password authenticationprotocol OSPA,” to appear in IEICE Trans.Commun, Vol. E86-B, No.7, 2003.[8]Anti-Phishing Working Group,.[9]/region/tw/enterprise/article/icq_threat.html.有关网络环境安全的黑客技术摘要：现在人们往往通过互联网处理事务。
华南理工大学广州学院本科生毕业设计（论文）翻译外文原文名Agency Cost under the Restriction of Free Cash Flow中文译名自由现金流量的限制下的代理成本学院管理学院专业班级会计学3班学生姓名陈洁玉学生学号200930191100指导教师余勍讲师填写日期2015年5月11日外文原文版出处：译文成绩：指导教师（导师组长）签名：译文：自由现金流量的限制下的代理成本摘要代理成本理论是资本结构理论的一个重要分支。
自由现金流代理成本有显着的影响。
在这两个领域相结合的研究，将有助于建立和扩大理论体系。
代理成本理论基础上，本研究首先分类自由现金流以及统计方法的特点。
此外，投资自由现金流代理成本的存在证明了模型。
自由现金流代理成本理论引入限制，分析表明，它会改变代理成本，进而将影响代理成本和资本结构之间的关系，最后，都会影响到最优资本结构点，以保持平衡。
具体地说，自由现金流增加，相应地，债务比例会降低。
关键词：资本结构，现金流，代理成本，非金钱利益1、介绍代理成本理论，金融契约理论，信号模型和新的啄食顺序理论，新的资本结构理论的主要分支。
财务con-道的理论侧重于限制股东的合同行为，解决股东和债权人之间的冲突。
信令模式和新的啄食顺序理论中心解决投资者和管理者之间的冲突。
这两种类型的冲突是在商业组织中的主要冲突。
代理成本理论认为，如何达到平衡这两种类型的冲突，资本结构是如何形成的，这是比前两次在一定程度上更多的理论更全面。
……Agency Cost under the Restriction of Free Cash FlowAbstractAgency cost theory is an important branch of capital structural theory. Free cash flow has significant impact on agency cost. The combination of research on these two fields would help to build and extend the theoretical system. Based on agency cost theory, the present study firstly categorized the characteristics of free cash flow as well as the statistical methodologies. Furthermore, the existence of investing free cash flow in agency cost was proved by a model. Then free cash flow was introduced into agency cost theory as restriction, the analysis shows that it will change agency cost, in turn, will have an impact on the relationship between agency cost and capital structure, finally, will influence the optimal capital structure point to maintain the equilibrium. Concretely, with the increasing free cash flow, correspondingly, debt proportion will decrease.Keywords:Capital Structure,Free Cash Flow,Agency Cost,Non-Pecuniary Benefit1. IntroductionAgency cost theory, financial contract theory, signaling model and new pecking order theory are the main branches of new capital structure theory. Financial con-tract theory focuses on restricting stockholders’ behavior by contract and solving the conflict between stockholders and creditors. Signaling model and new pecking order theory center on solving the conflict between investors and managers. These two types of conflict are the main conflict in business organizations. Agency cost theory considers how equilibrium is reached in both types of conflict and how capital structure is formed, which is more theory is more comprehensive than the previous two to some degree.……。
毕业设计（论文)外文资料翻译系别：专业：班级:姓名：学号:外文出处:附件： 1. 原文; 2。
译文2013年03月附件一：A Rapidly Deployable Manipulator SystemChristiaan J。
J。
Paredis, H. Benjamin Brown，Pradeep K. KhoslaAbstract:A rapidly deployable manipulator system combines the flexibility of reconfigurable modular hardware with modular programming tools，allowing the user to rapidly create a manipulator which is custom-tailored for a given task. This article describes two main aspects of such a system，namely，the Reconfigurable Modular Manipulator System （RMMS)hardware and the corresponding control software。
1 IntroductionRobot manipulators can be easily reprogrammed to perform different tasks, yet the range of tasks that can be performed by a manipulator is limited by mechanicalstructure。
Forexample，a manipulator well-suited for precise movement across the top of a table would probably no be capable of lifting heavy objects in the vertical direction. Therefore，to perform a given task,one needs to choose a manipulator with an appropriate mechanical structure.We propose the concept of a rapidly deployable manipulator system to address the above mentioned shortcomings of fixed configuration manipulators。
序号（学号）：040940131长春光华学院毕业设计（论文）译文Electronic technique电子技术姓名盛遵义教学院电气信息学院专业电子信息工程班级电信09401指导教师张淑艳（讲师）2013 年04 月10 日┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊Electronic techniqueFrom the world of radio in the world to a single chip， modern computer technology， industrial revolution， the world economy from the capital into the economy to knowledge economy。
Field in the electronic world， from the 20th century into the era of radio to computer technology in the 21st century as the center of the intelligent modern era of electronic systems。
The basic core of modern electronic systems are embedded computer systems (referred to as embedded systems)， while the microcontroller is the most typical and most extensive and most popular embedded systems。
radio has created generations of excellence in the world Fifties and sixties in the 20th century，the most representative of the advanced electronic technology is wireless technology， including radio broadcasting， radio，wireless communications (telegraph)，Amateur Radio， radio positioning，navigation and other telemetry， remote control， remote technology。
本科毕业设计（论文）外文翻译译文学生姓名：院（系）：油气资源学院专业班级：物探0502指导教师：完成日期：年月日地震驱动评价与发展：以玻利维亚冲积盆地的研究为例起止页码：1099——1108出版日期：NOVEMBER 2005THE LEADING EDGE出版单位：PanYAmericanYEnergyvBuenosYAiresvYArgentinaJPYBLANGYvYBPYExplorationvYHoustonvYUSAJ.C.YCORDOVAandYE.YMARTINEZvYChacoYS.A.vYSantaYCruzvYBolivia 通过整合多种地球物理地质技术，在玻利维亚冲积盆地，我们可以减少许多与白垩纪储集层勘探有关的地质技术风险。
通过对这些远景区进行成功钻探我们可以验证我们的解释。
这些方法包括盆地模拟，联井及地震叠前同时反演，岩石性质及地震属性解释，A VO/A V A,水平地震同相轴，光谱分解。
联合解释能够得到构造和沉积模式的微笑校正。
迄今为止，在新区有七口井已经进行了成功钻探。
基质和区域地质。
Tarija/Chaco盆地的subandean 褶皱和冲断带山麓的中部和南部，部分扩展到玻利维亚的Boomerange地区经历了集中的成功的开采。
许多深大的泥盆纪气田已经被发现，目前正在生产。
另外在山麓发现的规模较小较浅的天然气和凝析气田和大的油田进行价格竞争，如果他们能产出较快的油流而且成本低。
最近发现气田就是这种情况。
接下来，我们赋予Aguja的虚假名字就是为了讲述这些油田的成功例子。
图1 Aguja油田位于玻利维亚中部Chaco盆地的西北角。
基底构造图显示了Isarzama背斜的相对位置。
地层柱状图显示了主要的储集层和源岩。
该油田在Trija和冲积盆地附近的益背斜基底上，该背斜将油田和Ben i盆地分开（图1），圈闭类型是上盘背斜，它存在于连续冲断层上，Aguja有两个主要结构：Aguja中部和Aguja Norte,通过重要的转换压缩断层将较早开发的“Sur”油田分开Yantata Centro结构是一个三路闭合对低角度逆冲断层并伴随有小的摆幅。
The Authentication and Key Agreement Protocol Based on ECC for Wireless CommunicationsZhang JuanCollege of Management, Xi’an Technology of University,XATUXi’an ，Chinazhangj99999@Deng fangminXidian University,XiDianXi’an , China coopoo066@Abstract—In this paper, We proposed An efficient Authentication and key Agreement Protocol based on Elliptic Curve Cryptography (ECC). By which user to user, or user to network in the wireless communication system can authenticate one another and agree on a session key. We introduced ECC to the Diffie-Hellman Key Exchange Protocol, and added new Authentication Scheme using a certificate in the protocol. The use of ECC techniques provide greater security using fewer bits, resulting the protocol which requires significantly less bandwidth, and furthermore, it has lower computational burden and storage requirements on the user side.Keywords-Wireless communication protocol;ECC; Mutual authentication;Key agreementI.INTRODUCTIONToday, mobile communications technology has evolution for satisfying the customer needs continuously. It is expected for the future mobile communications to provide safety, health care, convenience, pervasive environments, knowledge based, high culture life, and human relationship services to users in time of beyond 2nd generation. With the popularity of mobile communication, the security of mobile networks becomes more and more important. However, due to the computation limitation, many existing authentication key agreement protocols are not suitable for wireless mobile networks. People find that using the protocol of public-key cryptosystem can solve these problems effectively, so in recent years, some protocol based on public-key cryptosystem has been proposed. For example, the well-known Yacobi - Shmuely Protocol (Yacobi etc, 1989) [1], ASK protocol (M. Aydos etc, 1998) [2], ASPeCT Protocol (Horn et al. 1998) [3] and so on. ASK Protocol and ASPeCT are based on elliptic curve cryptosystem which has 和higher efficiency in the current public-key cryptosystem field. The experiment ASK protocol in micro-operating system on the efficiency of theimplementation has been confirmed. Unfortunately, it has been proved that the ASK protocol exist the defect of being attacked by Known key, even can not complete the mutual authentication, and also has certain problems on user identity confidentiality. In this paper, we make construct a fast authentication and key agreement protocol based on elliptic curve cryptosystem Referred to as ECC-AKAP. The protocol evades the problems which exist in the above-mentioned protocols, achieves security conversation authentication and key agreement between arbitrary mobile users or between mobile users and network.A key agreement protocol is said to provide implicit key authentication if entity A is assured that no other entity aside from a specifically identified second entityB can possibly learn the value of a particular secret key.In 2005, Sui et al. proposed an efficient authentication key agreement protocol, but their protocol can not resist the off-line password guessing attack. Therefore, Lu et al. present an enhanced authentication key agreement protocol to against this attack. However, we find that their protocol can not withstand the parallel guessing attack. Here, we propose an improved authentication key agreement protocol based on elliptic curve Cryptography for wireless mobile networks.II．PRELIMINARIESA.Definitions and NotationsAn elliptic curve over the finite field Z q is defined as the set of points (x, y), satisfying the elliptic curve equation y2≡x3 + ax + b mod q, where x, y, a and b are the elements of the field. Note that the condition 4a3 + 27b2≡ 0 mod q should be met.h( ): one-way hash functionq: a large prime(q≥3)978-1-4244-4639-1/09/$25.00 ©2009 IEEEE: non-supersingular elliptic curveB: B∈E(F q) with order qx(Q): x coordinate of point QE k (m): symmetric encryption of message m using kD k ( c): symmetric decryption of ciphertext c using kX u : user u’s secret keyY u: u’s public key with Y u≡X u B mod pA→B: A sends message to Br u: a random number r∈ [2, n− 2]B.ECC Diffie-Hellman ProtocolThe algorithm Diffie - Hellman key exchange protocol based on elliptic curve cryptography runs as follows:1. A selects a random number r a and computes Y a =r a*B. Next, he sends Y a to B.2. Similarly, B computes Y b= r b*B, where nb is selected by B. He also sends Y b to A.3. A generates the session key K = r a*Y b. B generates the session key K = r b*Y a.Two keys computed in Step 3 are the same because r a*Y b = r a(nb*B) = r b(r a*B) = r b*Y a.The key agreement protocol achieved mutual protocol key exchange, but does not provide mutual authentication, an adversary can easily forge a message required in the protocol.III．PROPSED PROTOCOLA. Protocol DescriptionThe protocol assumed that user A and B had registeredat certification authority (CA), and CA generated and issued user digital certificate, which is in the use of Elliptic Curve Digital Signature. For example, CertA issued by CAfor user A, CertA = { ID a , Y a , ( d a ,s a) , e a , m a} , ID a : user A`s logo identity,Y a : User A's public key, Y a= r a*P,r a: User A's private key, r a∈ [2, n -2 ],( d a , s a ): a pair of integers which is denoted by CA for the user A, e a= h ( Y a , x, ID a , m a) ,m a: other information related A (such as: the certification expiration date) ,r ca : a pair of public key for CA,Y ca : a pair of private key for CA.Y ca, n and user identity are all open information. B efore running the protocol procedure, both A and B have theirown public key certificate copy only: CertA or CertB , andnone of them has opposite side's public key certificate. Theoverall goal of protocol is that the two sides for mutual authentication, then created a shared secret session key.protocol procedure runs as follows:A Bchooses r1∈(0, 1) m ,Calculates Y1= r1 * Pand send Y1 to BBchoosesr2∈(0, 1) mCalculates Y2= r2* PCalculates Y1b= r b*Y1, Y12= r2*Y1computes h ( Y12,Y1b ,CertB )and send Y2, CertB, h( Y12, Y1b ,CertB ) to AA Authenticates CertBCalculates Y12= r1 *Y2 ,Y1b= r1 * Y bAuthenticates h ( Y12,Y1b ,CertB )Calculates Y2a= r a * Y2Calculates E Y12 { CertA,Y2a}and send E Y12 { CertA,Y2a} to BB decrypts E Y12 { CertA,Y2a}Authenticates CertA andY2a = r2 *Y a=>(A and Bshare the session key Y12)Protocol running can be explained as follows:Within 1st step, A chooses a random r1, where 1 ≤r1 ≤n−1, then he calculates the point Y1 where Y1= r1− PFinally he sends Y1 to B.Within 2nd step, after B received Y1, he chooses a randomchallenge r2, where 1≤ r2≤ n −1, then computes Y2 whereY2= r2* P , Y1b= r b*Y1, Y12 = r2*Y1, h ( Y12,Y1b , CertB ) ,thensend Y2, CertB, h ( Y12, Y1b ,CertB ) to A.Within 3rd step, after A received the messages which Bsend in the second flow, at first he will verify CertB, If unsuccessful then A request B to resend. If A received message successfully, he will verify the value of Y12 =r1*Y2, Y1b= r1*Y b , by checking that h ( Y12,Y1b , CertB ), if so, if they match, then B authenticates, A and B can be confirmed that A has actually. A computes Y2a= r a* Y2 and E Y12 { certA, Y2a},then send messages E Y12 { CertA, Y2a } to B.Within 4th step, after B received the messages which A send in the 3rd flow, B decrypts the data sent through the channel, calculates the Y2a. If CertA is correct and Y2a = r2 *Y a , mutual authentication and key agreement completed, generate shared session key Y12. Otherwise, B inform A the failure of protocol implementation.The protocol forward mentioned achieves mutual authentication and key agreement, satisfies the basic protocol design goals, can be used for authentication and key agreement that one of the both communication sides who needs for the confidential identity.The certification process of mutual authentication for A to B: after received the message including Y2, CertB and h ( Y12, Y1b , CertB ),in the first place A validate CertB to obtain B's public key Y b, At this point A can calculate Y1b = r1 *Y b, Y12 = r1 *Y2, then verify the one-way function h ( Y12, Y1b , CertB )in the end.The opponent E could not find Y1b if he did not know B's private key r b,and can not generate h ( Y12, Y1b , CertB ). If the opponent gave a counterfeit information Y2, CertE, h (Y12, Y1e ,CertE ), A could immediately identified counterfeit information through the certificating the authentication.The certification process of mutual authentication for B to A: after B received the messages E Y12 { CertA, Y2a}, , B decrypts the data and obtain CertA and Y2, then B Authenticates A`s certificate and obtain Y a, Calculates Y′2a= r2 * Y a, compares Y′2a and Y2a , if Y′2a=Y2a is true , it means that the authentication of a to b has been completed. Because of the impossibility for the opponent E to obtain Y12, so the news can not be forged in this process.B.Further Discussion on ProtocolThe protocol forward mentioned can be used for authentication and key agreement that one of the both communication sides who needs for the confidential identity .Slightly modified it can generate the other two agreements: one is that the two communication sides for the authentication and key agreement do not need the confidential identity.In the new protocol, we only need to amend the plan transferred on the third step A to B CertA, h ( Y12, Y2a , CertA ). Now we can find that if the protocol did not needto provide the user A's identity confidential, the efficiencyof the implementation improved.The other is the certification and key agreement with a initialized payment. Assuming that A is the depositor and B is the bank, A allows B to pay the merchant on behalf of ID m.We can modify the third step protocol above as follows:E Y12 { sig a( ID m , ID b , py, TS ) , h ( Y2, py, TS ) , certA }, Adding a digital signature so that A do not deny that he had sent payment requests to B. Py expresses payment quantity, TS expresses timestamp, sig a( x) expresses the message x which A signed ) .IV．ANALYSIS ON PROTOCOLA. Security AnalysisThe protocol calculation security referred above based on elliptic curve discrete logarithm problem and one-way security function. The following public key cryptography protocol on some common security problems [1, 9] for discussion.Know-key Security: Suppose that opponent E has derived session keys of past communication sessions, But that is useless for E to obtain the new session or counterfeit any participants since in our proposed protocol, the client and the server both generates new r1 and r2 every new session, and in addition the shared key Y12 is generated with every new session also. Assuming that the elliptic discrete problem is intractable, thus our proposed protocol is secure against any opponent known key attacks.Perfect forward secrecy: Suppose that opponent E had known A or B’s private key (even both A and B’s) , it is also difficult for E to obtain the old session key consulted between A and B. the session key Y12= r1*Y2= r2*Y1=r1 *r2 *P, r1 is a random numbers generated form A, r2 is a random numbers generated form B. in the network the data transported is not r1or r2 but Y1 and Y2. It is impossible for opponent E to solve the elliptic curve discrete logarithm problem in order to retrieve the value of password. Thus, our protocol satisfies the property of perfect forward secrecy.Replay attack: Suppose that opponent E Replay A’s message, because E have not known A’s private key, so he can not obtain the third step message E Y12{ CertA, Y2a},if opponent E replay B’s message Y2, CertB, h ( Y12, Y1b ,CertB ) , From the above mutual authentication process, from validating B’s certificate A can find the wrong message so E fail to replay attack.B.Analysis on Implementation of EfficiencyThe protocol based on Elliptic Curve Cryptography can provide a greater security in a smaller quantity of keys, reduce the required bandwidth significantly, and slow down the computational burden of the client and storage requirements greatly. In addition, because of the hash function used in the protocol design, the protocol also significantly reduces the amount of traffic information. This protocol can be used in 3rd generation wireless communication as a security protocol due to its bandwidth and storage efficiency and fast execution timing performance.V．CONCLUSIONSToday, wireless network access are very important for users. This paper describes a new network access mechanism for wireless local area networks. In this paper, at first we first analyzes the importance and Probability for public key cryptography protocol to substitute Shared key protocol, then propose a mobile communications certification and key agreement protocol based on Elliptic Curve Cryptosystem, and introduce two deformation of the agreement. Analysis shows that our protocol can not only overcome the problems existing in the current major public-key protocol but also have higher efficiency and security.R EFERENCES［1］M. Aydos, B. Sunar and C. K. Koç. (1998 )An Elliptic Curve Cryptography based Authenticationand Key Agreement Protocol for WirelessCommunication [C]. Workshop Discrete Algorithmsand Methods for Mobility (DIAL’98), Dallas, TX.Oct.［2］M. Aydos, T. Yan1k and C. Koc.( 2001) High-Speed Implementation of an ECC-based WirelessAuthentication Protocol on an ARMMicroprocessor[C]. IEE Proceedings: Communications, 148(5):273-279.［3］Kumar Mangipudi et al.( 2004)Attacks and Solutions on Aydos-Sunar-Koç’s Wireless AuthenticationProtocol[C]. Globecom 2004. IEEECommunications Society. pp 2229-2234.［4］Lawrence C. Washington.( 2003) Elliptic Curves: Number Theory and Cryptography [M]. New York.CRC Press. pp 89-175.［5］Hung-Min Sun. (2004)Cryptanalysis of Aydos et al.’s ECC-Based wireless Authentication Protocol[C]. Proceedings of the 2004 IEEE internationalConference on e-Technology, e-Commerce ande-Commerce and e-Service (IEEE’04). IEEE Computer Society.。
