对一类超混沌图像加密算法的密码分析与改进
摘要
This Letter proposes two different attacks on a recently proposed image based on hyper-chaos. The cryptosystem under study proceed first by shuffling the image rows and columns to disturb the high correlation among pixels by iterating the logistic map. Second, a keystream is generated to mix it with the pixels of the shuffled image using hyper-chaos. These two processes in the encryption stage present weakness, and a chosen plaintext attack and a chosen ciphertext attack can be done to recover the ciphered-image without any knowledge of the key value. It just demands three couples of plaintext/ciphertext to break totally the cryptosystem.
关键字：Cryptanalysis， Chaotic encryption ，Keystream ，Hyper-chaos ，Shuffle
1 介绍
Some researchers have pointed out that there exists tight relationship between chaos and cryptography [1–7]. Many fundamental characteristics of chaos, such as the ergodicity, mixing and exactness property and the sensitivity to initial conditions, can be connected with the “confusion” and “diffusion” property in cryptography. So it is a natural idea to use chaos to enrich the design of new ciphers. As a consequence, there have been proposed many chaotic ciphers in a very huge variety of design. We are interested on those dedicated to the image encryption. Image encryption is somehow different from text encryption due to some inherent features of image, such as bulk data capacity and high correlation among pixels. So far, many chaos-based image cryptosystems have been proposed [8–18]. Although a number of them have been cryptanalyzed, many others have not been effectively attacked like the one in [8]. In this Letter, we propose to break the image encryption algorithm proposed by T. Gao and Z. Chen in [8]. First, this paper gives a detailed introduction of the cryptosystem, as a basis of the whole Letter. The image encryption scheme under study consists of two parts: The image encryption based on total shuffling matrix, and the mixing operation of the shuffled image with a keystream generated
from a hyper-chaotic system. First, an image of size N ×M is considered, every pixel of this plain image is noted Pi, j, with i = 0, . . . ,M ? 1 and j = 0, . . . , N ? 1. By using the logistic map given by Eq. (1) departing from an initial condition x0:
After some iterations n, a new x0 is derived from the final iteration xn and a number hi is calculated:
The iteration of the logistic map will continue until getting M different data between 0 and M ? 1 noted hi , i = 0, . . . ,M ?1. Then rearrange the rows of the plain image P according to {hi , i = 0, . . . ,M ?1}. hi will be the i th row in
the shuffled rows image noted Ph. Then, this process is repeated to shuffle the column position of every row in Ph to obtain a totally shuffled image in rows and columns Phl . The equation used to calculate the position of the shuffled column of every row is:
for every column i = 1, . . . ,M and row j = 1, . . . , N.
Second, an hyper-chaotic system given by (4) is used:
The encryption scheme is based on the combination of state variables of the above hyper-chaotic system according to these steps:
(1) First, the system on (4) is iterated for N0 times.
(2) Four variables are generated from the hyper-chaotic system and then transformed to integers applying the following:
(3) Generate .x1 using the following:
According to the value of .x1, three variables (B1, B2, B3) from the four variables
(x1, x2, x3, x4) generated from (5) are chosen to perform encryption operation using an association table (for more details to perform this step, the reader is advised to see Table 2 in Ref. [8]). And then, three pixels from the plain shuffled image
Phl are mixed with the keystream Bk, k = 1, . . . , 3, like the following:
Pi and Ci , i = 1, 2, . . . , N×M, represent the pixel of the plain shuffled image
Phl and the ciphered image C, respectively.
(4) Continue on iterating the hyper-chaotic system, and go to step (2) until the whole image is totally ciphered.
The decryption algorithm is similar to the encryption algorithm. hat is, for the encrypted image, firstly, decrypt the image using hyper-chaotic system with the same parameters and initial values as that used in encryption, and then anti-shuffle the resulting image, we will get the original image. As claimed in [8], the initial values of Logistic map and hyper-chaotic system are used as secret keys. For more details, the reader is referred to [8].
2. Classical types of attacks
When cryptanalyzing a cryptosystem, the general assumption made is that the cryptanalyst knows exactly the design and working of the cryptosystem under study, i.e., he knows everything about the cryptosystem except the secret key. This is an evident requirement in today’s secure communications networks, usually referred to as Kerchoff’s principle [19]. There are four classical types of attacks and it is possible to differentiate between different levels of these attacks based on the level of knowledge of the attacker to the cryptosystem and if or not he has the encryption/decryption machinery or knowledge of some couple of plaintext/ciphertext. So, we enumerate them ordered from the hardest types of attack to the easiest:
(1) Ciphertext only: the opponent possessesjust a string of ciphertext.
(2) Known plaintext: the opponent possesses a string of plaintext, M, and the corresponding ciphertext, D.
(3) Chosen plaintext: the opponent has obtained temporary access to the encryption machinery. Hence he can choose a plaintext string, M, and construct the corresponding ciphertext string, D.
(4) Chosen ciphertext: the opponent has obtained temporary access to the decryption machinery. Hence he can choose a ciphertext string, D, and construct the corresponding plaintext string, M.
In each of these four attacks, the objective is to determine the key that was used. It suffices that one of the attacks is successful
to consider an algorithm insecure.
3. Weakness of the cryptosystem based on the hyper-chaoticmap
The cipher under study behaves as a stream cipher [19]. The operation of the algorithm as a stream cipher can be explained as follows. Assume that K is the key, given by
nitial conditions of the hyper-chaotic system and that P composed by Pi is the plaintext. A keystream B = B1B2 . . . is generated using Eqs. (4) and (6). This keystream is used to encrypt the plaintext according to the rule:
Decrypting the ciphertext string C can be accomplished by computing the keystream B given the knowledge of the key K and undoing the operations eBi .
The most serious problem of this cryptosystem is to make the generation of the keystream the same for every plaintext/ciphertext. Next, it is shown how to recover the keystream using chosen ciphertext and chosen plaintext attacks. We note that knowing the keystream B generated by a certain key K is entirely equivalent to knowing the key [20]. Moreover, the shuffling process (1st process of the encryption procedure) of the plain image is weak and can be guessed with a chosen plaintext and chosen ciphertext attacks
3.1. Chosen plaintext attack CPA
Assume that we have a ciphertext C = C1C2 . . . (the ciphered image written as a
ector of length N ×M), to decrypt without knowing the key K. We assume that we
have obtained temporary access to the encryption machinery. We describe the steps leading to recover the plain image P from the ciphered image C:
(1) We request the ciphertext of the plaintext M = m1m2 . . . = 00000. . . : a plaintext of the same size of the ciphertext C constructed by the pixels of values mi = 0 for every i = 1, 2, . . . , N ×M. We obtain the ciphertext D =d1d2 . . . . The keystream B = B1B2 . . . can be generated from D by:
for every i = 1, 2, . . . , N ×M.
The recovered shuffled image Phl = Phl 1 Phl 2 . . . can be obtained using
the calculated keystream B and the ciphertext C:
for every i = 1, 2, . . . , N ×M.
(2) We request now the ciphertext of an image M ×N noted J whose all the rows of
its first column is composed by the value pixel 1, all the rows of the second column is composed by 2, and so on, until the last column N whose all its rows is composed with the value N:
To show an example, we will consider that M = N = 4, so
The corresponding ciphered image is noted J c = Jc1 Jc2 . . .. With the calculated
keystream B in step (1), we generate the shuffled image J hl = J1 J2 . . . of J by
applying the following:
With the given example, we find that
Fig. 1. Chosen plaintext attack
So, for a 4 ×4 matrix, for the first row, the columns were ordered in the form of {li,1, i = 1, . . . , N} = 1, 2, 3, 4. For the second row, the columns were ordered in the form of {li,2, i = 1, . . . , N} = 1, 4, 3, 2. For the third row, the columns were ordered in the form of {li,3, i = 1, . . . , N} = 2, 1, 3, 4. And for the last row, the columns were ordered in the form of {li,4, i = 1, . . . , N} = 4, 2, 3, 1. We will use these li, j to generate the image Ph by rearranging the columns of every row in the shuffled image Phl which was recovered from the ciphered image in step (1). This can be generalized for any matrix with rows less or equal than 256.
(3) We request now the ciphertext of an image M ×N noted I whose all the columns
of its first row is composed by the value pixel 1, all the columns of the second
row is composed by 2, and so on, until the last row M whose all its columns is composed with the value M:
To show an example, we will consider that M = N = 4, so
The corresponding ciphered image is noted Ic = Ic1 Ic2 . . .. With the calculated
keystream B in step (1), we generate the shuffled image Ihl = I1 I2 . . . of I by applying the following:
With the given example, we find that
One can verify easily that Ih = Ihl because the columns values are the same for every row. So, for a matrix composed by 4 rows, the rows were ordered in the form of {hi , i = 1, . . . ,M} = 4, 3, 2, 1. We will use these hi to generate the recovered image P by rearranging the rows of the image Ph recovered from step (2).
Fig. 1 gives a graphic description of the chosen plaintext attack.
Table 1 gives a detailed description of the CPA steps on a ciphered image of size 4 ×4. In Fig. 2, we show the simulations results of a Chosen plaintext attack on the Ciphered Lena image of size 256×256.
Table 1
Steps leading to recover the plain image P of size 4×4 from the ciphered image C n a CPA scenario
Fig. 2. (a) Original image of Lena P; (b) Ciphered image C; (c) Chosen plain image M = zeros(M, N); (d) Shuffled image Phl ; (e) Chosen plain image J; (f) Shuffled image Ph ; (g) Chosen plain image I ; (h) Recovered image of Lena P .
3.2. Chosen ciphertext attack CCA
Assume that we have a ciphertext C = C1C2 . . ., to decrypt without knowing the key K. We assume that we have obtained temporary access to the decryption machinery.
We describe the steps leading to recover the plain image P from the ciphered image C:
(1) We request the plaintext of the ciphertext D = d1d2 . . . = 00000. . . : a ciphertext of the same size of the ciphertext C constructed by the pixels of values di = 0 for every i = 1, 2, . . . , N×M. We obtain the plaintext M =m1m2 . . . . The keystream B = B1B2 . . . can be generated from M by:
for every i = 1, 2, . . . , N ×M.
The recovered shuffled image Phl = Phl 1 Phl 2 . . . can be obtained using the calculated keystream B and the ciphertext C:
for every i = 1, 2, . . . , N ×M.
(2) We construct an image Ihl of size M ×N whose all the columns of its first row
is composed by the value pixel 1, all the columns of the second row is composed by 2, and so on, until the last row M whose all its columns is composed with the value
M. To show an example, we will consider that M = N = 4, so
We request now the plaintext of Ic = Ihl ⊕B, B was calculated in step (1). The corresponding plain image is noted I = I1 I2 . . .. With the given example, we find that
So, for a matrix composed by 4 rows, the rows were ordered in the form of {hi , i = 1, . . . ,M} = 3, 4, 1, 2.
Fig. 3. Chosen ciphertext attack.
(3) We construct an image J hl of size M×N whose all the rows of its first column
is composed by the value pixel 1, all the rows of the second column is composed by 2, and so on, until the last column N whose all its rows is composed with the value
N. To show an example, we will consider that M = N = 4, so
We request now the plaintext of the image J c = J hl ⊕B, B was calculated in step (1). The corresponding plain image is noted J h = J h 1 J h 2 . . . . With the given
example, we find that
(4) And then, we will use the result of step (2) to rearrange the rows of J using the calculated {hi , i = 1, . . . ,M} = 3, 4, 1, 2, we will find the matrix
So, for a 4 ×4 matrix, for the first row, the columns were ordered in the form of {li,1, i = 1, . . . , N} = 2, 1, 4, 3. For the second row, the columns were ordered in the form of {li,2, i = 1, . . . , N} = 2, 4, 1, 3. For the third row, the columns were ordered in the form of {li,3, i = 1, . . . , N} = 3, 2, 4, 1. And for the last row, the columns were ordered in the form of {li,4, i = 1, . . . , N} = 1, 3, 4,
2. These li, j are then used to reconstruct the order of the columns of the shuffled image Phl found in step (1). We find the image Ph.
(5) We will use the result of step (2) to rearrange the rows of Ph using the calculated {hi , i = 1, . . . ,M} = 3, 4, 1, 2, we will find the recovered image P .
Table 2
Steps leading to recover the plain image P of size 4 ×4 from the ciphered image C in a CCA scenario
Fig. 3 gives a graphic description of the chosen ciphertext attack. Table 2 gives a detailed description of the CCA steps on a ciphered image of size 4×4.
4. Conclusion
In this Letter, two attacks were presented to break a recently chaotic cryptosystem based on a hyper-chaotic system. It has been shown that the reuse of the keystream more than once makes it weak against chosen ciphertext, chosen plaintext attacks. The generated keystream neither depends on the plaintext nor does it depend on the ciphertext, which makes it unchangeable in every encryption process. Moreover, the process of shuffling the image is predictable and we can extract the original image from the shuffled image. Three couples of plaintext/ciphertext were enough to break the cryptosystem in a chosen ciphertext and chosen plaintext attacks scenarios. Note that in the case where the cryptosystem make the keystream changes in every encryption procedure, that will make it secure and the described attacks will be harmless to the algorithm. Changing the keystream either means (1) to change the key in every encryption procedure and by that the cryptosystem will be more like a one time pad [19] which is a kind of a stream cipher whose never reuse its key, in this case, the cryptosystem will be totally secure but we have to affront the distribution key problem and many others issues that make the one time pad impractical in a real secure communication. (2) or to make the generation of the keystream dependent to the plaintext or the ciphertext, and that will make the keystream change for every encryption procedure without changing the key. Doing so, the cryptosystem will be designed in a CBC (Cipher-Block Chaining [21]) or PCBC (Propagating Cipher-Block Chaining [22]) mode of block encryption. This solution is more adequate than to change the cryptosystem as a one time pad because it is
secure enough and practical in the same time.
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外国语学院2018届毕业论文文献综述（示范） 一、研究背景 近来多篇论文中出现零翻译的提法（杜争鸣，2000；邱懋如，2001；刘明东，2002；袁斌业，2002a，2002b，2002c，2002d；石琳，2003；余清萍，2003；余清萍，秦傲松，2004；肖耀田，2004），但国内学者所编三本译学词典（林煌天，1997；孙迎春，1999；方梦之，2004）均未出现零翻译这一词条，国外三本词典/术语著作（Shuttleworth & Cowie，1997；Baker，1998；Delisle，2004）亦未收入这一条目，只有国内孙迎春（2001）编著的《汉英双向翻译学语林》收进了“零翻译（音译、形译之一种）zero translation”（58页）及“zero translation零翻译（音译、形译之一种）”（268页）两个条目，同时又有贾影（2002）反对零翻译提法，并认为承认不可译有“积极作用”。但零翻译现象确实存在，如DIY（自己动手），IQ（智商），EQ（情商），这些零翻译词汇经常在汉语中出现。英语中也有类似情况，如美国《时代》周刊中报道中国特色事物时经常使用拼音，如aizi(矮子)，pizi（痞子），shiganjia（实干家），yuan（缘）（王祥兵，2002），shuangying(双赢)，guanxi(关系)（顾静，2005）。 这些研究成果揭示了零翻译现象的存在，引进了零翻译的概念，促进了翻译理论概念的扩大，但是从发表的论文及孙迎春（2001）的这两个条目来看，各自运用的名称虽同（也有不同，如杜争鸣称为不译），但概念的内涵及外延均有出入，因此有必要探讨当前零翻译研究的问题并提出相应研究对策。 二、研究现状及不足 1. 定义不统一、模糊不清 传统翻译理论多把零翻译归结为“音译法”、“移译法”，只看到技巧层面的意义，如秦建栋（1999）讨论“英汉词汇空缺现象刍议”列举“音译法”、“移译法”，袁斌业（2001）论及“英语本族人音译汉语词汇的语用分析”，虽然看到“音译在我国只能用来翻译名词，而在国外则可以用来翻译包括名词在内的各种词语”，但未能从中提炼出零翻译的概念，实际上这里已包含有零翻译与音译的某些区别。 国内最早使用zero translation这一术语的是杜争鸣（2000），但他称之为“不译”，并分析了直译、意译与不译三种翻译策略。他不停留于策略本身，从跨文化交际的视角分析了三种策略的社会语言学与跨文化交际涵义，并看到了不译的三层文化含义。不译背后体现译者对于翻译目的的认识，“而翻译的目的必然直接或间接地反映反映译者本人对翻译的文化含义的意识与潜意识，反映他翻译时所采取的文化姿态与立场。”即翻译观的问题。但从术语的精确性来说
Household Register Under Supervision of the Ministry of Public Security of P. R. C. ANNOUNCEMENTS 1.Household register has the legal validity that certifies the attorney ship of a citizen and the
relationship of family members, and it is the main reference for the censor and checkup of domiciliary register which is undertaking by the household registration authority. When the functionary of household registration authority censor and verify the household register, the householder and members of this family shall take the initiative in presenting the household register. 2.The householder shall take the household register in safekeeping; the household register is prohibited to be altered, transferred and leased. When the household register is lost, the household registration authority should be informed. 3.The right for registering the household register shall be performed by the household registration authority; any other unit and individual shall not make any records on the booklet. 4.The member of this family shall go to the household registration authority for transacting the declaration and registration, applying bring with the booklet, in case of the increase and decrease of the members and the alteration of registration items. 5.In case of that the whole family moves out of the residency, the household register shall be turned in and cancelled. Record of Dwelling Address Alteration
翻译理论知识 一、翻译的定义 学习一门新的学科，首先必须有一个科学的定义。翻译是一个包罗万象、博大精深的技艺，至今也没有一个统一规范、举世公认的定义。我们只能综合各种不同的定义来掌握翻译的本质。 1. The Definition of The Oxford English Dictionary To turn from one language into another. 2. The Definition of Webster’s Third New International Dictionary of the English Language To turn into one’s own or another language. 3. A good translation is one which the merit of the original work is so completely transfused into another language as to be as distinctly apprehended and as strongly felt by a native of the country to which that language belongs as it is by those who speak the language of the original work.好的翻译应该是把原作的长处完全地移注到另一种语言，以使译人语所属国家的本地人能明白地领悟、强烈地感受，如同使用原作语言的人所领悟、所感受的一样。（泰特勒，1790） 4. Translation consists in reproducing in receptor language the closest natural equivalence of the source language , first in terms of meaning and secondly in terms of style.翻译就是在译入语中再现与原语的信息最切近的自然对等物，首先是就意义而言，其次是就文体而言。 （奈达，1974） 5. 翻译是用一种语言把另一种语言所表达的思维内容准确而完整地重新表达出来的语言活动。（张培基，1980） 6. 翻译是把一种语言表达的意义用另一种语言传达出来，以达到沟通思想感情、传播文化知、促进社会文 明，特别是推动译语文化兴旺昌盛的目的。（孙致礼：2003） 7. 翻译是将一种语言文字所蕴含的意思用另一种语言文字表达出来的文化活动。 （王克非，1997） 二、翻译的分类 翻译分不同的类型。就文本而言，随着世界发展的全球化趋势，翻译的范围越来越广，涵盖各个领域，如文学、政治、文化、贸易、科技、传媒等。在这个意义上，翻译可分为文学翻译、科技翻译和实用文体翻译。 1.按语言分类：本族语译成外语、外语译成本族语/ 语内翻译（intralingual translation）、语际翻译（interlingual translation） 2.按活动形式分类：笔译（translation）、口译（oral interpretation） 3按翻译材料的文体分类：应用文体翻译、科技文体翻译、文学作品翻译、政论作品翻译 4按处理方式分类：全译、节译、摘译、编译、译述 三、翻译的标准 翻译标准就是指翻译实践时译者所遵循的原则，也是翻译批评家批评译文时必须遵循的原则。翻译是一种社会活动，翻译标准则是从中产生的。由于社会活动受制于社会条件及译者个人等等因素，因此翻译标准也就打上了深深的社会和译者的烙印。 在我国持这一翻译原则的有玄奘、严复和鲁迅等人。玄奘是唐代著名的佛经翻译家，主张翻译"既须求真又须喻俗"(A good translation should be both faithful to the original and intelligible to the public.)，意即译文要"忠实通顺"。严复是我国清末时期的名学者。他在《天演论》(译例言)(1898)中提出了"信达雅"三字标准(faithfulness, expressiveness and elegance)。"信"是"意义不背本文"，"达"是不拘原文形式，尽译文语音的能事以求原意明显。"信"、"达"互为照应，不可分割开来。"雅"在今天看来是不可取的，因为这个"雅"是用汉以前字法句法，即所谓的上等文言文。鲁迅先生认为："凡是翻译，必须兼顾两面，一当然力求其易解，一则保存着原作的丰姿。"这就是说，译文既要信又要顺(both faithful to the SL and smooth in expression)。我国当代翻译理论家张培基等人在其《英汉翻译教程》中所提出的"忠实"、"通顺"标准也属此类型。从
Heavy Oil Development Technology of Liaohe Oilfield Han Yun (Scientific Research Information Department Exploration&Development Research Institute，Liaohe Oilfield Company) Liaohe Oilfield，the largest heavy oil production base in China，features in various reservoir types，deep burial，and wide range of crude oil viscosity．For many years，a series of technologies have been developed for different oil products and reservoir types of the oilfield，of which water flooding，foam slug drive，steam stimulation，steam drive,and SAGD are the main technologies. After continuous improvement，they have been further developed and played an important role in the development of heavy oil in the oilfield． Liaohe Oilfield is abundant in heavy oil resources，46％of the total proved reserves of Liaohe Oilfield Company. Horizontally the resources concentrates in the West Depression and the southern plunging belt of the Central Uplift in Liaohe Rift. Vertically,it is mainly distributed in Paleocene Shahejie Formation(ES). The distinctive geological feature of Liaohe 0ilfield is manifested in three aspects：first，the heavy oil reservoirs are deeply buried and 80％of them are buried more than 900m deep；second，the heavy oil viscosity ranges widely．For most of the reservoirs．the dead oil viscosity ranges in 100～100000mPa·s with the maximum 650000mPa·s.Third the reservoir types are various with complicated oil—water relationship，most of the reservoirs are edge water and bosom water reservoirs and there are also edge water reservoirs，top water reservoirs and bosom water reservoirs．For more than 20 years of development，Liaohe Oilfield has developed series of heavy oil development technologies for different oil products and different types of reservoirs，such as water flooding, foam slug drive,steam stimulation steam drive and SAGD．The most difficult issues have been overcome in the development of the super
A Clear Look at Internal Controls: Theory and Concepts Hammed Arad (Philae) Department of accounting, Islamic Azad University, Hamadan, Iran Barak Jamshedy-Navid Faculty Member of Islamic Azad University, Kerman-shah, Iran Abstract: internal control is an accounting procedure or system designed to promote efficiency or assure the implementation of a policy or safeguard assets or avoid fraud and error. Internal Control is a major part of managing an organization. It comprises the plans, methods, and procedures used to meet missions, goals, and objectives and, in doing so, support performance-based management. Internal Control which is equal with management control helps managers achieve desired results through effective stewardship of resources. Internal controls should reduce the risks associated with undetected errors or irregularities, but designing and establishing effective internal controls is not a simple task and cannot be accomplished through a short set of quick fixes. In this paper the concepts of internal controls and different aspects of internal controls are discussed. Keywords: Internal Control, management controls, Control Environment, Control Activities, Monitoring 1. Introduction The necessity of control in new variable business environment is not latent for any person and management as a response factor for stockholders and another should implement a great control over his/her organization. Control is the activity of managing or exerting control over something. he emergence and development of systematic thoughts in recent decade required a new attention to business resource and control over this wealth. One of the hot topic a bout controls over business resource is analyzing the cost-benefit of each control. Internal Controls serve as the first line of defense in safeguarding assets and preventing and detecting errors and fraud. We can say Internal control is a whole system of controls financial and otherwise, established by the management for the smooth running of business; it includes internal cheek, internal audit and other forms of controls. COSO describe Internal Control as follow. Internal controls are the methods employed to help ensure the achievement of an objective. In accounting and organizational theory, Internal control is defined as a process effected by an organization's structure, work and authority flows, people and management information systems, designed to help the organization accomplish specific goals or objectives. It is a means by which an organization's resources are directed, monitored, and measured. It plays an important role in preventing and detecting fraud and protecting the organization's resources, both physical (e.g., machinery and property) and intangible (e.g., reputation or intellectual property such as trademarks). At the organizational level, internal control objectives relate to the reliability of financial reporting, timely feedback on the achievement of operational or strategic goals, and compliance with laws and regulations. At the specific transaction level, internal control refers to the actions taken to achieve a specific objective (e.g., how to ensure the organization's payments to third parties are for valid services rendered.) Internal control
文献综述 大学生时间管理研究——以郑州大学西亚斯国际学院为例 姓名：代永寒学号：20091211205 专业：工商管理班级：工本2班 史蒂芬?柯维的《要事第一》 “要事第一”，顾名思义是指重要的主要的事情要放在第一时间去完成。而在实际工作中我们往往是将认为急迫的紧要的事情放在第一时间完成； 本书通过四个象限来告诉我们如何区分事情的紧急性与重要性，从而告诉我们在平常的工作中应怎样去区分事情属轻属重，以及造成事情紧急性的原因，在平常工作中要注意哪些方面以避免出现紧急事件的情况。 第一象限包括四点：A危机 B 急迫的问题C最后期限迫近的项目 D 会议准备工作等。第一象限显得紧迫与重要，但我们要知道形成第一象限的紧迫与重要主要是因被延误及没有进行计划与预测及计划所致。第二象限包含准备工作、预防、价值、筹划、建立关系、真正的再创造与赋予能力。第二象限属于质量象限，属于重要但不紧迫的事情，但我们必须要去做，因只有这样才能避免出现第一象限包含的情况。第三象限包含干扰、电话；邮件、报告；某些会议；很多临近、急迫的事情及很多流行的活动。第三象限包括“紧急但不重要的事情”，而事实上它易给人造成假象，从而形成第一象限情况。第四象限包含琐事、打发时间的工作、某些电话，解闷，“逃避”行为、无关紧要的邮件及过多地看电视；第四象限属于既不紧急也不重要的事情，它是浪费象限，第四象限中的行为是堕落行为。这四个象限告诉我们如果在办事过程中不是以重要性而是以紧要性为出发点，就会出现第一第三甚至第四象限的情况，在平常的工作中，我们要加以区分，日常工作生活中往往事情越是紧迫，反而说明事情越不重要！像最近存货系统因急着想能早日上线，在运作过程中被卡住，故一心想着去解决软件中存在的问题，而忽略了与其他人员的沟通协调，存货上软件固然重要，但与公司整体运作相比就稍显其次，没合理分配其他人员手头事项，这样会导致其他问题的增多，从而会出现第一第三象限甚至于第四象限的浪费情况。 “要事第一”，告诉我们在日常的工作与生活中要从以下方面着手加以区分、
第1 课绪论--翻译概述（1） 一、学科特点 翻译是一种跨越时空的语言活动，是"把一种语言已经表达出来的东西用另 一种语言准确而完整地重新表达出来"(范存忠："漫谈翻译"《翻译理论与技巧》 中国对外翻译出版公司，1985，p.80), 是"从语义到文体在译入语中用最切近而 又最自然的对等语再现原语的信息"（谭载喜：《奈达论翻译》中国对外翻译出版 公司，1984，p.10）。翻译虽为个体所承作，却是一种社会活动，一门综合性很 强的学科。它既有很强的理论性又有丰富的实践内涵。就前者而言，翻译经过千 百年来各国翻译家的共同努力，已经在语言学、文学、文化、心理学、人类学、 哲学和教育学等学科的基础上初步建立了一套理论体系，并在具体实践中总结出 了一套行之有效的跨文化和语言转换模式。随着科学的日益进步，这种体系和模 式正处在不断地完善之中。就后者而言，翻译是人类社会活动的产物，具有很强
的实践性。翻译理论与实践的关系是辨证的；翻译理论产生于翻译实践，反过来 又指导实践，实践转过来又丰富翻译理论。可以说，没有社会实践就不会有翻译 理论的产生；没有翻译理论作为指导，翻译实践就会难免走弯路。因此，学好翻 译既要重视翻译理论的学习，又要加强翻译实践；理论联系实际，这是我们学好 翻译的必由之路。 二、为什么可能有翻译 翻译是人类社会发展和进步的需要，因为人类社会要发展进步就需要在不同 文化的民族之间进行沟通，而这一全过程都离不开翻译。正如Steiner 和张培基 所说的那样：Translating it is that openeth the window, to let in the light; that breaketh the shell, that we may eat the kernel. (Steiner) 翻译是沟通各族人民的思 想，促进政治、经济、文化、科学、技术交流的重要手段，也是进行国际斗争的 必要武器。翻译是学习好外语的重要手段之一，也是探讨两种语言对应关系的一 门学科。(张培基等)
中英文对照外文翻译文献 (文档含英文原文和中文翻译) OIL UNDER ICE DETECTION: WHAT IS THE STATE-OF-THE-ART? Abstract. Since the exploration for oil and gas in the Canadian and US arctic commenced in the early 1970s, a need has been identified to develop technology to detect oil under ice. Both electromagnetic and acoustic sensors have been tried, but a practical field instrument has not been identified. Most proposed systems require that the equipment be operated from the ice surface in order to get adequate coupling and, for some systems, the snow must be removed from the ice. For many ice
situations, surface access is difficult and poses a severe safety issue. Two recent spills in Alberta used “high technology” ice augers to detect the presence of oil under the ice. Some potential new techniques are discussed and the basic principles of their operation described. Keywords: arctic, oil spill response, oil in ice, detection 1. Introduction The detection of oil under continuous ice cover has presented one of the most difficult challenges to the oil-spill technological community for the past two decades and there is still no operationally proven system available. Dickins (2000) under the sponsorship of the US Minerals Management Service conducted an excellent review of the status of oil-under-ice detection and this paper complements this review with a more detailed analysis of some systems. Dickins identified many false start concepts, which will not be discussed in this paper. In order to determine the design of a suitable oil-under-ice detector, the various situations under which oil may be found under a continuous ice sheet need to be considered. The oil must come from a sub-surface release since any surface release would either be on the ice surface or in a lead or other opening in the ice. Potential sources of sub-surface oil are a leak in a pipeline, the leakage from a submerged tank or vessel or a natural seep. Oil when trapped under ice does not spread rapidly or cover a large area due to natural
引子:鉴于现在对外交流事例逐渐增多,英文合同特不是经济合同的翻译愈显重要,若译文不准确或不严谨,势必会引起不必要的经济纠纷.故今以一英文(经济)合同写作书籍为蓝本,录入一些有益文字,希望大伙儿共同提高英文(经济)合同的翻译和写作。 合同文件是合同双方签订并必须遵守的法律文件,因此合同中的语言应体现其权威性.英文合同用语的特点之一就表现在用词上,即选择那些法律用词,以及正式用词,使合同表达的意思准确无误,达到双方对合同中使用的词无可争议的程度。 一.Hereby 英文释义:by means of , by reason of this 中文译词:特此,因此,兹 用法:常用于法律文件、合同、协议书等正式文件的开头语；在条款中需要强调时也可用。 语法：一般置于主语后,紧邻主语. 注释: (1)hereby: by reason of this 特此
(2)covenant: v. make a formal agreement 立约,签订合同、条约; n. legal agreement具有法律约束的正式合同 (3)completion of the Works: 工程的竣工 (4)therein: in the Works在本工程中 (5)the Contract Price: 合同总价,指工程的总造价 (6)such...as: 关系代词,相当于that, which (7)under: in accordance with 依照,按照 (8)the provisions of the Contract: terms and conditions of the Contract合同条款 注释： （1）hereby：特此 （2）to the best of our knowledge：as far as we know据我们所知 （3）foregoing statement：above-mentioned statement上述声明 （4）herein：in this, in the statement在声明中 （5）documentary proof：证明文件
会计内部控制中英文对照外文翻译文献(文档含英文原文和中文翻译) 内部控制系统披露—一种可替代的管理机制 根据代理理论，各种治理机制减少了投资者和管理者之间的代理问题（Jensen and Meckling，1976； Gillan，2006）。传统上，治理机制已经被认定为内部或外部的。内部机制包括董事会及其作用、结构和组成（Fama，1980；Fama and Jensen，1983），管理股权(Jensen and Meckling，1976)和激励措施，起监督作用的大股东(Demsetz and Lehn，1985)，内部控制系统(Bushman and Smith，2001)，规章制度和章程条款(反收购措施)和使用的债务融资（杰森，1993）。外部控制是由公司控制权市场(Grossman and Hart,1980)、劳动力管理市场（Fama,1980）和产品市场（哈特,1983）施加的控制。 各种各样的金融丑闻，动摇了世界各地的投资者，公司治理最佳实践方式特别强调了内部控制系统在公司治理中起到的重要作用。内部控制有助于通过提供保证可靠性的财务报告，和临时议会对可能会损害公司经营目标的事项进行评估和风险管理来保护投
资者的利益。这些功能已被的广泛普及内部控制系统架构设计的广泛认可，并指出了内部控制是用以促进效率，减少资产损失风险，帮助保证财务报告的可靠性和对法律法规的遵从（COSO,1992）。 尽管有其相关性，但投资者不能直接观察，因此也无法得到内部控制系统设计和发挥功能的信息，因为它们都是组织内的内在机制、活动和过程（Deumes and Knechel,2008）。 由于投资者考虑到成本维持监控管理其声称的（Jensen and Meckling，1976）,内部控制系统在管理激励信息沟通上的特性，以告知投资者内部控制系统的有效性,是当其他监控机制（该公司的股权结构和董事会）比较薄弱，从而为其提供便捷的监控（Leftwich et等, 1981）。存在的替代机制一直是人们在不同公司治理文献中争论的话题（Rediker and Seth, 1995；Fernandez and Arrondo，2005），基于威廉姆森（1983年）的替代假说认为，特定控制机制的边际作用取决于其在公司治理制度的相对重要性。 在本文中，我们认为披露内部控制系统的特点是在管理者选择的监控机制时存在一个可替代治理机制。Leftwich（1981）认为“管理者选择一个监控包，监测包的组成取决于各种监控机制的成本与效益”（P.59）。 特别是，我们重点关注内部控制系统和监控包的另外两个机制 (公司的所有权结构和董事会) 间的关系，根据有关文献（Jensen and Meckling，1976；Fernandez and Arrondo，2005；Gillan，2006）它们在管理行为监控方面发挥相关作用。我们假设认为，内部控制系统的特性取决于激励由企业的股权结构和董事会发挥监督作用。 因此,我们研究了三年间在四个不同的证券交易所上市（伦敦、巴黎、法兰克福和米兰）160家欧洲公司内部控制系统披露程度，通过利用这个国际范例,我们能够描绘出不同的体制环境的某些功能。 我们发现证据表明内部控制系统披露代替了监测方面所发挥的作用与所有制结构、制度所有权、在董事会上独立董事比例和会计审计委员会的专家成员的比率相关。 我们再加上通过内部会计控制的披露所发挥的管理作用，采用以往文献的完整披露架构，使我们能够详细地从内容和信息管理的程度上内制披露上进行交流。而公司治理的最佳做法要求披露内部控制系统的特性，他们没有提供管理应该披露和披露程度的指令。这样的管理缺乏指示使内部控制系统存在随意性。 本文提供了实证支持威廉姆森（1983年成立）在不同的治理机制下的替代假说，它有相应的政策含义。虽然大多数公司治理研究考虑一个互补的披露机制管理采用强化公
附录 图像科学综述 近几年来，图像处理与识别技术得到了迅速的发展，现在人们己充分认识到图像处理和识别技术是认识世界、改造世界的重要手段。目前它己应用于许多领域，成为2l世纪信息时代的一门重要的高新科学技术。 1.图像处理与识别技术概述 图像就是用各种观测系统以不同形式和手段观测客观世界而获得的，可以直接或间接作用于人眼而产生视知觉的实体。科学研究和统计表明，人类从外界获得的信息约有75%来自于视觉系统，也就是说，人类的大部分信息都是从图像中获得的。 图像处理是人类视觉延伸的重要手段，可以便人们看到任意波长上所测得的图像。例如，借助伽马相机、x光机，人们可以看到红外和超声图像：借助CT可看到物体内部的断层图像；借助相应工具可看到立体图像和剖视图像。1964年，美国在太空探索中拍回了大量月球照片，但是由于种种环境因素的影响，这些照片是非常不清晰的，为此，美国喷射推进实验室(JPL)使用计算机对图像进行处理，使照片中的重要信息得以清晰再现。这是这门技术发展的重要里程碑。此后，图像处理技术在空间研究方面得到广泛的应用。 总体来说，图像处理技术的发展大致经历了初创期、发展期、普及期和实用化期4个阶段。初创期开始于20世纪60年代，当时的图像采用像素型光栅进行扫描显示，大多采用巾、大型机对其进行处理。在这一时期，由于图像存储成本高，处理设备造价高，因而其应用面很窄。20世纪70年代进入了发展期，开始大量采用中、小型机进行处理，图像处理也逐渐改用光栅扫描显示方式，特别是出现了CT和卫星遥感图像，对图像处理技术的发展起到了很好的促进作用。到了20世纪80年代，图像处理技术进入普及期，此时购微机已经能够担当起图形图像处理的任务。VLSL的出现更使得处理速度大大提高，其造价也进一步降低，极大地促进了图形图像系统的普及和应用。20世纪90年代是图像技术的实用化时期，图像处理的信息量巨大，对处理速度的要求极高。 21世纪的图像技术要向高质量化方面发展，主要体现在以下几点：①高分辨率、高速度，图像处理技术发展的最终目标是要实现图像的实时处理，这在移动
英语专业文献综述 The Standardization Office was revised on the afternoon of December 13, 2020
Y i b i n U n i v e r s i t y 2015届本科毕业论文文献综述 题目_翻译目的论指导下的英语介词汉译策略研究 二级学院外国语学院 专业英语 学生姓名简汝梦 学号年级 2011级 指导教师徐文英职称讲师 年月日 文献综述 翻译目的论指导下的英语介词汉译策略研究 Study on the Translation Strategies of English Prepositions Based on Skopos Theory 摘要：英语介词使用频率高，搭配能力强，含义灵活，因此在翻译中属于比较难以处理的一种词类。目的论论者认为翻译是有明确的目的和意图，在译者的作用
下，以原文文本为基础的跨文化的人类交际活动。目的论以文本目的为翻译过程的第一准则，目的决定了译者需要采用何种翻译策略和方法。目的论的提出为英语介词的汉译提供了可靠的指导。本文将目的论引入到介词翻译中，认为在目的论原则的指导下，英语介词的汉译可通过加词、减词、分译、转译等策略来达到较好的翻译效果以及更好地实现翻译目的。 关键词：英语介词；翻译；目的论 导言：随着时代的发展，以及中国入世的大好形势的出现，汉语与英语在世界上似乎显得同等重要，所以将这两种语言互相转化是我们越来越重要的任务。在英语中，英语介词数量不多，但其构成的介词短语在英语中的出现频率很高，功能多样且位置灵活，对构成句子具有重要作用，因此对于英语介词的翻译策略问题一直深受广大翻译学者的关注。目的论以文本目的为翻译过程的第一准则，目的论者认为翻译是一种有目的的活动，目的决定了译者需要采用何种翻译策略和方法，即“目的决定论”。目的论的提出为英语介词汉译提供了有效的指导。因此，译者若能熟练掌握翻译目的和翻译方法，则能译出高质量的译文。鉴于此，本文先是阐述各大专家对于英语介词翻译以及翻译目的论的已有研究和探索，并结合笔者自己的观点加以评述；然后以此综述在翻译目的论指导下研究英语介词的汉译策略是个切实可行的手段；最后预测此观点的发展前景一定是光明受欢迎的。 历史发展：对于翻译目的论的发展历程，笔者在总结各前辈的资料中得出：在20世纪70年代，功能主义翻译理论兴起于德国，其四大代表性人物及其理论是: 凯瑟林娜·赖斯(Katharina Reiss)的功能主义翻译批评理论(functional category
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。