Designing Internal Control System To Minimize Fraud And
Designing Internal Control System For Mfis
Parveen Mahmud, FCA, Deputy Managing Director
Palli Karma-Sahayak Foundation (PKSF), Bangladesh A BSTRA CT
In section 1.0 this paper gives an introduction to Microfinance Institutions (MFIs) informal financial service delivery mechanism which are not under any regulatory framework like the formal sector. So, there is a necessity to internalize a built-in internal control system through self-regulation to mitigate exposure to risk in MFI. In 2.0 sound and reliable management system for MFIs through self-regulation are discussed. Section 3.0 discussed under internal control its basic criteria: appropriateness, consistency and cost effectiveness. In section 4.0 an overview of risk management of MFIs are discussed under different dimensions: governance risk, management risk which are split into operating risk and financial risk. Financial risk is again sub-divided under portfolio risk, liquidity risk and interest risk. Under section 5.0 tools for effective internal control in MFI are discussed. Section 6.0 portrays steps for designing internal controls for MFI. In section 7.0 conclusion has been drawn that the internal control can be expected to provide only reasonable assurance.
1. INTRODUCTION
Microfinance Institutions (MFIs) are informal financial service providers and are not under any regulatory framework like the formal sector. On the demand side the MFIs offer collateral-free loans. Social collateral replaces material collateral through an intangible micro-network of mutual accountabilities. Again, from the supply side, distinct characteristics of MFIs in Bangladesh are not- for profit organizations. Board members are not shareholders, they do not have financial stakes. MFIs through microcredit programs (MCPs) mobilize poor and distressed target people and extend collateral- free small loans to them with the objective of creating self-employment for poverty alleviation. The most important asset in MFIs is the portfolio, and the liability is the savings deposit taken from the poor MCP members. Savings mobilization takes place as a source of funding for the Revolving Loan Fund (RLF). A distinct characteristic of MFIs is its informal, decentralized process of service delivery technology. Although they have a Central Head Office, the MCP is operated at the grass root level through Branches. For better administration Branches are organized under Regions and if necessary, Regions under Divisions. Though the average individual loan size in the MCP is small, the number of transactions is high. At the field level, the amount of cash handling is also high, which creates opportunities for fraud. MFIs can partially compensate for structural shortcomings by practicing self regulation through effective internal control system linked to sound risk management strategies. It will keep the MFIs on the track to achieve a sustainable MFI corporate culture.
2.0 SELF-REGULATION
“The basic concept of self-regulation is the “internal good governance” on the basis of: shared values and principles, shared standards among MFIs, local network as local value
guardian for ensuring “standard”.”1 Self-regulation is expected to be ingrained within the MFIs integrated management system to ensure sound and organized growth on a sustainable basis. And, the dormant attribute is “internal control” to minimize risk management. Broadly, Governance and Accountability are essential elements for self- regulated integrated management system. Specific requirements are:
a) A strong and capable board of directors that establishes sound program interventions,
financial and risk management policies and ensures management accountability for
effectively implementing these policies.
b)Developing standard accounting system that is transparent and acceptable universally
c)An intensive and extensive internal audit function to confirm that the approved
policies are followed and procedures are effective.
d)Development of effective mechanism for saver’s protection
e)Efficient management and an effective Management Information System (MIS).
f)Development of effective financial and operational performance standard.
g)High quality external auditing by competent auditors experienced in microcredit as an
objective check on internal control systems to protect against fraud and
mismanagement.
h)Strategic monitoring of financial performance standards, program performance and
compliance of the code of norms/conducts by competent management.
3.0INTERNAL CONTROL
It is a set of integrated methods and procedures translated into regular and periodic activities that preserves safety of asset (e.g. loan portfolio, cash and other physical assets etc), improves client service, ensures reliability of financial information and staff adherence to management policies and guidelines. It ensures, (i) systems of accountability along with prevention of errors and irregularities, and (ii) systems of detecting errors and irregularities. Management must ensure that a proper internal control structure is instituted, reviewed, and updated to keep it effective. It must satisfy three basic criteria:
They must be appropriate (that is, the right control in the right place and commensurate to the risk involved).
They must function consistently as planned throughout the period (that is, be complied with carefully by all employees involved and not bypassed when key personnel are away or the workload is heavy).
They must be cost effective (that is, the cost of implementing the control should not exceed the benefits derived).
4.0 RISK MANAGEMENT FOR MFIs
Risk is intrinsic in MFIs mode of operation for providing financial services.To minimize the risk factor MFIs should link internal control to risk management. Risk management is the process of assessment of relative risk and ensuring that controls are present and effective. It covers prevention of potential problems and the early detection of actual problems when they occur. Risk management of MFIs have different dimensions as follows:
https://www.doczj.com/doc/ee13962813.html,ernance Risk
2.Management Risk:
a) Operating Risk, and
a)Financial Risk: (i) Portfolio Risk, (ii) Liquidity Risk and (iii)
Interest Risk
1 Self-regulation workshop held in New Delhi on August 29-30 and organized by INAFI
4.1 Governance Risk
Governance is a process by which Board Members, through management, guide an MFI in fulfilling its corporate mission while protecting the MFI’s assets. As board members do not have a material stake, in competent, commitment, sincerity with good reputation should be the basis for selection of board members. Well defined, clear procedures and documentation of board meetings are essential.
4.2 Management Risk
Management plays a key role behind the success or failure of MFIs through a set of activities (including planning and decision making, organizing, leading, and controlling) directed at an MFI's resources (human, financial, physical, and information) for a cost-effective, self-reliant and sustainable organization. Clear and transparent operational guidelines and policies, such as: organograms, functions of different sections, staff responsibilities, accounts-keeping formats etc., can help to develop a good system of internal control to mitigate management risk of MFIs. The entire operational system deserves surveillance by management to see if it is working as prescribed and if changes are warranted. In its broadest sense, internal control to management risks refers to both administrative control and accounting control. Management risk can be broadly divided into two categories as follows:
4.2.1 Operating Risk
Operating risk refers to the risk of losses or unexpected expenses associated with fraud, inefficiency, errors and unforeseen contingencies. Steps for reduction of operating risks are: Reliable Personnel with Clear Responsibilities:Individuals must be given authority, responsibility, and duties commensurate with their abilities, interests, experience, and reliability. Appropriate recruitment and reward-punishment systems are of utmost importance in these regards. Responsibility means tracking actions as far down in the organization as is feasible, so that results can be related to individuals. It means having field-workers/supervisors sign MIS report, accountant’s init ial cash book/general ledger, and field-workers sign savings/loan pass books and group attendance-registers etc. Communication : Regular co-ordination meetings to be held frequently at the central as well as at the field level with a view to having a clear analysis of the problems that arise in the course of implementation of the programs.
Physical Safeguards:Access to resources and records is to be limited to authorized individuals who are accountable for their custody or use. To ensure accountability, the resources are to be periodically compared with the recorded amounts.
Losses of cash, inventories, and records are minimized by safes, locks, guards, and restricted access to assets. POs should take special precaution for preserving cash in vaults. Documents should also be kept in lockers.
Rotation of Duties: To avoid risk key people handling cash or inventories should have job rotations.
4.2.2 Financial Risk
Asset and liability management refers to the financial risk management of an MFI. Genera lly, any action to increase the expected returns of an MFI will also increase its risk structure. The major categories of asset and liability management risk that an MFI needs to consider are:
4.2.2.1 Portfolio Risk
The primary revenue-earning asset of a micro credit organization is its portfolio, and portfolio risk management guards against potential losses resulting from the poor quality of the organization’s loan portfolio assets. The following factors are directly related to maintaining the desired quality of loan portfolio.
1. Program placement
3. Samity management
3. Loan disbursement and recovery system
4. Skill of field workers (including Branch managers)
5. Regular Internal supervision (degree of supervision on both field workers and samity
member borrowers).
6. Incentive base for management staff and employees.
7. Sound Governance
8. Capability of Chief Executive
9. Accuracy of MIS report
10.Offsite monitoring tools for analyzing MIS reports with particular focus on loan
portfolio quality.
4.2.2.2Interest Rate Risk
Interest rate risk arises when interest rates on assets and interest rates on liabilities (which fund the assets) are mismatched. Interest rate risk is primarily of concern to MFIs that mobilize deposits, and / or have relatively long term loans (of greater than one year). In MFIs assets are frequently short-term (loans, term deposits, and so on), while liabilities are frequently long term (concessional loans). This results in a funds gap. Gap positions will have to be managed effectively to maintain (or achieve) financial sustainability.
4.3 Liquidity Risk
Liquidity management and cash flow management are often used interchangeably. In fact, liquidity management includes the management of not only cash but also other short term assets and short term liabilities, bill payments, and debt repayment. An MFI is in a liquid position if it is able to meet its current obligations as they become due, if demands for funds are readily met while balancing the need to earn revenue. This can be avoided thro ugh a budgetary practice.
TOOLS FOR EFFECTIVE INTERNAL CONTROL
5.0
Internal control is a process. It is a means to an end, not an end in itself. Internal control systems are fundamental to the success and survival of MFIs. It is a moving target. It must be monitored and adapted to fit the circumstances. Internal control is geared to the achievement of objectives in one or more separate but overlapping categories. Microfinance management may be defined as “an operational system of microfinance services that starts from organizing groups, mobilizing savings, selecting borrowers, disbursing microcredit, collecting repayment, recycling loan, preventing defaulters and defalcation as well keeping systematic records and reports towards the end of poverty allev iation ”.In designing effective internal control system for MFIs the following criteria needs attention:
5.1 Segregation of Duties
Key duties and responsibilities in authorizing, processing, recording, and reviewing transactions and events should be separated among individuals. Internal control is effected by people. It is not merely producing and distributing policy manuals and forms, it is monitoring people at every level of the organization. The separation of tasks not only helps ensure accurate compilation of data, but also limits the chances for fraud that would require the collusion of two or more persons. This extremely important and often neglected element can be subdivided into four parts:
Separation of operational responsibility from record keeping responsibility. The entire accounting function should be separated from operating departments so that objective, independent records may be kept either by other operating people or by clerks. For example, cash and other ledgers should be kept by accountant, not by the cashier or field workers. The accountant/store clerk, not store keeper, should keep inventory records.
Separation of the custody of assets from accounting: This practice reduces temptation and fraud. For example, the bookkeeper should not handle cash, and the cashier should not have access to ledger accounts such as the individual records of micro-credit clientele.
In a computerised system, a person with custody of assets should not have access to programming or any input records. Similarly, an individual who handles programming or input records should not have access to tempting assets.
Separation of the authorization of transactions from the custody of related assets: To the extent feasible, persons who authorize transactions should not have control over the related asset. For instance, the same individual should not authorize the payment of a supplier’s invoice and also sign the check in payment of the bill. Nor should an individual who handles cash receipts have the authority to indicate which accounts receivable (e.g. loan outstanding) should be written off as uncorrectable.
Separation of duties within the accounting function: An employee should not be able to record a transaction from its origin to its ultimate posting in a ledger. Independent performance of various phases will help ensure control over errors.
5.2 Authorization and Execution of Transactions and Events
Transactions and significant events are to be authorized and executed only by persons acting within the scope of their authority. All transactions will require approval and authorization by a responsible official. The limits of delegation of approving authority and financial power limits should be clearly defined and who approves what should also be defined spec ifically. Authorization can be either general or specific.
General authorization must be given in written form. It often sets definite limits on loan ceiling, savings instruments, rate of service charge, daily/travel allowance, and so forth. There may also be complete prohibitions (against taking extra fees or any facility from microcredit borrowers, etc).
Specific authorization usually means that a superior manager must permit (typically in writing) any particular deviations from the limits set by general authorization. For example, the chief executive, rather than the branch manager, may have to approve any distress loan (i.e. interest free loan given from disaster management fund). Another example is the need
for approval from the board of directors/executive committee regarding expenditures for capital assets in excess of limits specified in the budget.
5.3 Documentation
The internal control structure and all transactions and significant events are to be clearly documented, and the documentation is to be readily available for examination. Transactions and significant events are to be promptly recorded and properly classified e.g. loan proposals along with group resolutions and savings-loan collection-sheet to journals and ledgers. Immediate, complete, and tamper-proof recording is the aim. To this end pre-numbered source documents and registers should be in practice to ensure recording.
5.4 Monitoring and Supervision
Competent supervision is to be provided to ensure that internal control objectives are achieved. To be effective, controls should fulfill their intended purpose in actual application.
A set of controls designed to operate in a manual environment may not be effective in an automated environment. Therefore, the controls selected should provide the coverage they are supposed to provide and operate when intended. As for efficiency, controls should be designed to derive maximum benefit with minimum effort. Controls tested for effectiveness and efficiency should be those in actual operations and should be evaluated over time to ensure that they are continually used.Operations staff / managers are to continually monitor their savings and loan operations through field visits and take prompt, responsive action on all findings of irregular, uneconomical, inefficient, and ineffective operations. In the supervision of MCP’s aspects of considerations are:
?Use of loan outside the proposed IGA/ unproductive activity
?Hidden Overdue
?Violation of Traditional Micro Credit Culture
?False Vouching
?False Disbursement
?Fictitious Cash in Hand
?Social motivation to recover the default loan
?Find out the causes of defalcation of loan
?SWOT analysis for default loan recovery
?Insufficient MIS, AIS and poor record keeping
5.5 Management Information System (MIS) and A ccounting Information System (AIS)
The starting point in developing an MIS is to determine what information the MFI needs to perform well. That means defining the needs of different users of information. Good information provided in a useful form on a timely basis empowers all the stakeholders in the institution- donors, investors, regulators, clients, other institutions, board members, executive management, the accounting department, the credit department, branch managers, field staff, and all other staff- to participate meaningfully in the institution. MIS is one of the most critical but least understood elements of a successful MFI. The AIS is one of the two parts of an MFI’s MIS. A good information system can transform an organization. Aspects that ne ed to be considered are:
?Adequate MIS formats
?Correct and proper use of the MIS formats
?Hierarchy in Reporting System
?Ageing of delinquent loan
?Double Entry and Accrual Accounting System
?Create Debt Management Reserve (DMR)
?Proper recording of default loan recovered
5.6 Internal audit
Internal auditing is an independent appraisal function established within MFI’s which examines and evaluates its activities as a service to the organization. Internal auditing is essential for ensuring the operation and appropriateness of controls (therefore essential for good management), but frequently neglected for financial reasons. It is unwise to be dogmatic about the detailed responsibilities of internal auditors, as these will vary a great deal between MFI’s and e ven through time for the same entities. Responsibilities might include:
?Evaluating the effectiveness of internal controls
?Ensuring the reliability and integrity of financial management system of record keeping and reporting
?Ensuring safeguard of assets
?Promoting orderly, economical, efficient, and effective operations and quality products and services consistent with the organization's mission;
Ensuring adherence to laws, regulations, and management directives; and
5.7 The Management Letter
External Auditing gives scope to evaluate internal controls system of MFIs which is reported through the Management Letter. This is at times called the“Weakness Letter”. The objectives of this letter are :
To identify any weaknesses in the internal control.
To suggest adequate accounting control
To suggest improvements in existing internal controls.
6.0 STEPS FOR DESIGNING INTERNA L CONTROL SYSTEM
Once an MFI’s management identifies its sources of risk, it can design measures for an effective system of internal controls. There are five basic steps in the design of an internal control system.
Step 1:Define and describe the objective of the internal control system in the operative context of the MFI by using the performance standards benchmark.
Step 2: Describe the system: list services offered, include a flow chart of operations, detail organizational structure and procedures, provide a chart of accounts, and specify staff positions and responsibilities. Particular attention should be paid to the guidelines for inspection and internal auditing.
Step 3: Determine tasks that need crosschecks or verifications to prevent error or fraud, and separate them, for example, collections, payments and recording of such transactions.
Step 4:Create an annual work plan to implement the internal control system delegating assignments among staff.
Step 5: Organize the internal control system so that each step is linked with some detailed control documents that are cross-checked by an assigned person or team.
7.0 CONCLUSION:
Internal control can be expected to provide only reasonable assurance, not absolute assurance, to an entity’s management and board. It inspires confidence in the MFI by its stakeholders. No internal control structure by itself, however detailed and co mprehensive, can guarantee efficient administration and complete and accurate records or be foolproof against fraud, especially when those involved hold positions of authority or trust.
Acknowledgements:
1. PKSF’s Internal Control Policy for MFIs,
2. Microfinance Handbook: Joanna Ledgerwood
赛区评阅编号（由赛区组委会填写）： 2016年高教社杯全国大学生数学建模竞赛 承诺书 我们仔细阅读了《全国大学生数学建模竞赛章程》和《全国大学生数学建模竞赛参赛规则》（以下简称为“竞赛章程和参赛规则”，可从全国大学生数学建模竞赛网站下载）。 料 我们的报名参赛队号（12位数字全国统一编号）： 参赛学校（完整的学校全称，不含院系名）： 参赛队员 (打印并签名) ：1. 2.
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系泊系统的设计和探究 摘要 本文利用牛顿力学定律，力矩平衡原理、非线性规划、循环遍历法等方法对系泊系统进行了设计与探究。通过对系泊系统各组件和浮标运用牛顿经典力学体系进行分析，得到了各个情况下的钢桶倾斜角度、锚链状态、浮标吃水深度和游动区域。 ?， 。当风 对于第二问，求解当海面风速为36m/s时，浮标的吃水深度和游动区域、钢桶以及钢管的倾斜角度和锚链形态。利用第一问中的力学方程和程序，求得钢桶的倾角为19.5951?和四节钢管的倾斜角度依次为19.756?、19.755?、19.916?、20.076?。浮标的游动区域为以锚在海面上的投影为圆心，半径为18.8828m的圆。由于部分数据与问题二中钢桶的倾斜角度不超过5?，锚链在锚点与海床的夹角不超过16?的要求不符，所以通过调节重物球的质量使钢桶的倾斜角度和锚链在锚点与海床的夹角处在要求的范围之内。借助MATLAB程序中的循环遍历法，可以求得重物球的质量3770kg。
系泊系统的设计 摘要 对于问题一，建立模型一，已知题目给出的锚链长度与其单位长度的质量，得到悬链共210环。对各节锚链，钢桶，四节钢管受力分析得出静力平衡方程，使用分段外推法，可以得到静力平衡下的迭代方程。其中锚对锚链的拉力大小方向为输入变量，迭代的输出变量为浮标的位置和对钢管的拉力，在给定的风速下，输入和输出满足关系2)2(25.1cos 水v h T -=α，αθcos cos 11T T =，通过多层搜索算法得出最符合的输入输出值，即可得到给定风速下浮标的吃水深度，浮标拉力、锚链与海床夹角。利用MATLAB 软件编程求解模型得到：风力12m/s 时，钢桶与竖直方向上的角度1.9863度，从下往上四节钢管与竖直方向夹角为1.9652度、1.9592度、1.9532度、1.9472度，浮标吃水0.7173m ，以锚为圆心浮标的游动区域16.5125m ，锚链末端切线与海床的夹角3.8268度。风力24m/s 时，锚链形状，钢桶与竖直方向上的夹角3.9835度，从下往上四节钢管与竖直方向夹角为3.9420度、3.9301度、3.9183度、3.9066度，浮标吃水0.7244m ，以锚为圆心浮标的游动区域18.3175m 。锚链末端切线与海床夹角15.9175度。 对于问题二的第一小问，使用模型一求解，当风速36m/s 时，锚链末端切线与海床夹角26.3339度，浮标吃水0.7482m ，浮标游动区域为以锚为圆心半径为18.9578m 的圆形区域，从下往上四节钢管与竖直方向倾斜角度为8.4463度、8.4225度、8.3989度、8.3753度，钢桶与竖直方向倾斜角度为8.5294度。为满足问题二的要求，在模型一的基础上把重物球质量作为变量，建立模型二，将钢桶倾斜角小于5度和锚链前端夹角小于16度当做两个约束条件，通过MATLAB 编程求解得到满足约束条件要求的重物球质量取值范围为3700kg 到5320kg 。 对于问题三，首先取不同水深、水速、风速三种情况，建立模型三，即在模型一的基础上增加水流对系统产生的影响。在三种情况下，找到合适的锚链型号、锚链长度，重物球质量，对吃水深度、游动区域、钢桶的倾斜角三个目标进行优化达到最小。通过MATLAB 编程实现该模型三得到结果：选用Ⅲ型锚链，锚链长度为27.24m ，重物球质量为2580kg 。 关键词：平面静力系分析 多层搜索算法 遗传算法 逐步外推法 多目标优化
系泊系统的设计和探究 This model paper was revised by the Standardization Office on December 10, 2020
赛区评阅编号（由赛区组委会填写）： 2016年高教社杯全国大学生数学建模竞赛 承诺书 我们仔细阅读了《全国大学生数学建模竞赛章程》和《全国大学生数学建模竞赛参赛规则》（以下简称为“竞赛章程和参赛规则”，可从全国大学生数学建模竞赛网站下载）。 我们完全明白，在竞赛开始后参赛队员不能以任何方式（包括电话、电子邮件、网上咨询等）与队外的任何人（包括指导教师）研究、讨论与赛题有关的问题。 我们知道，抄袭别人的成果是违反竞赛章程和参赛规则的，如果引用别人的成果或资料（包括网上资料），必须按照规定的参考文献的表述方式列出，并在正文引用处予以标注。在网上交流和下载他人的论文是严重违规违纪行为。 我们以中国大学生名誉和诚信郑重承诺，严格遵守竞赛章程和参赛规则，以保证竞赛的公正、公平性。如有违反竞赛章程和参赛规则的行为，我们将受到严肃处理。 我们授权全国大学生数学建模竞赛组委会，可将我们的论文以任何形式进行公开展示（包括进行网上公示，在书籍、期刊和其他媒体进行正式或非正式发表等）。 我们参赛选择的题号（从A/B/C/D中选择一项填写）： 我们的报名参赛队号（12位数字全国统一编号）： 参赛学校（完整的学校全称，不含院系名）： 参赛队员 (打印并签名) ：1.
2. 3. 指导教师或指导教师组负责人 (打印并签名)： （指导教师签名意味着对参赛队的行为和论文的真实性负责） 日期：年月日 （请勿改动此页内容和格式。此承诺书打印签名后作为纸质论文的封面，注意电子版论文中不得出现此页。以上内容请仔细核对，如填写错误，论文可能被取消评奖资格。） 赛区评阅编号（由赛区组委会填写）： 2016年高教社杯全国大学生数学建模竞赛 编号专用页 赛区评阅记录（可供赛区评阅时使用）： 送全国评阅统一编号（赛区组委会填写）： 全国评阅随机编号（全国组委会填写）：
摘要 本题要求观测近海观测网的组成，建立模型对其中系泊系统进行设计，在不同风速和水流的情况下确定锚链，重物球，钢管及浮标等的状态，从而使通讯设备的工作效果最佳。求解的具体流程如下： 针对问题一，分别对系统中的受力物体在水平方向和竖直方向上的力进行分析，找出锚链对锚无拉力时的临界风速，运用力矩平衡求出钢管与钢桶的倾斜角度。对于锚链，将其等效为悬链线模型，根据风速不同判断锚链的状态，从而求出结果。 ?时能够正常工针对问题二，需要调节重物球的质量，使通讯设备在36m m 作。为了确定重物球的质量，首先将实际风速与临界风速进行比较，判断此时系统中各物体的状态，与题目中已知数据进行比较。在钢桶倾斜角度达到临界角度时，计算锚链与海床的夹角并于题中数据进行比较，计算重物球的质量。在浮标完全没入海面时，计算相应条件下重物球的质量，从而确定满足条件的重物球的质量范围。 针对问题三，要求在不同条件下，求出系泊系统中各物体的状态。以型号I 锚链为例，当水流方向与风速方向相同时，系统条件最差，分析在不同水深条件下的系泊系统设计。由题中已知条件确定系统设计的限制条件，对系统各物体进行受力分析，以使整体结果最小，即可得出最优的系泊系统设计。 # 》 关键词：悬链线多目标非线性规划 @
一、问题重述 近浅海观测网的传输节点由浮标系统、系泊系统和水声通讯系统组成（如图1所示）。某型传输节点的浮标系统可简化为底面直径2m、高2m的圆柱体，浮标的质量为1000kg。系泊系统由钢管、钢桶、重物球、电焊锚链和特制的抗拖移锚组成。锚的质量为600kg，锚链选用无档普通链环，近浅海观测网的常用型号及其参数在附表中列出。钢管共4节，每节长度1m，直径为50mm，每节钢管的质量为10kg。要求锚链末端与锚的链接处的切线方向与海床的夹角不超过16度，否则锚会被拖行，致使节点移位丢失。水声通讯系统安装在一个长1m、外径30cm 的密封圆柱形钢桶内，设备和钢桶总质量为100kg。钢桶上接第4节钢管，下接电焊锚链。钢桶竖直时，水声通讯设备的工作效果最佳。若钢桶倾斜，则影响设备的工作效果。钢桶的倾斜角度（钢桶与竖直线的夹角）超过5度时，设备的工作效果较差。为了控制钢桶的倾斜角度，钢桶与电焊锚链链接处可悬挂重物球。 系泊系统的设计问题就是确定锚链的型号、长度和重物球的质量，使得浮标的吃水深度和游动区域及钢桶的倾斜角度尽可能小。 问题1某型传输节点选用II型电焊锚链，选用的重物球的质量为1200kg。现将该型传输节点布放在水深18m、海床平坦、海水密度为×103kg/m3的海域。若海水静止，分别计算海面风速为12m/s和24m/s时钢桶和各节钢管的倾斜角度、锚链形状、浮标的吃水深度和游动区域。 | 问题2在问题1的假设下，计算海面风速为36m/s时钢桶和各节钢管的倾斜角度、锚链形状和浮标的游动区域。请调节重物球的质量，使得钢桶的倾斜角度不超过5度，锚链在锚点与海床的夹角不超过16度。 问题3 由于潮汐等因素的影响，布放海域的实测水深介于16m~20m之间。布放点的海水速度最大可达到s、风速最大可达到36m/s。请给出考虑风力、水流力和水深情况下的系泊系统设计，分析不同情况下钢桶、钢管的倾斜角度、锚链形状、浮标的吃水深度和游动区域。 二、模型假设 1.不考虑流体对锚链的作用，忽略锚链本身的伸长，锚链沿长度均匀分布； 2.假设风是二维的，只存在平行于水平面的风速，不存在垂直方向上的分量；
数学建模A题系泊系统 设计 HEN system office room 【HEN16H-HENS2AHENS8Q8-HENH1688】
系泊系统的设计 摘要 本题要求观测近海观测网的组成，建立模型对其中系泊系统进行设计，在不同风速和水流的情况下确定锚链，重物球，钢管及浮标等的状态，从而使通讯设备的工作效果最佳。求解的具体流程如下： 针对问题一，分别对系统中的受力物体在水平方向和竖直方向上的力进行分析，找出锚链对锚无拉力时的临界风速，运用力矩平衡求出钢管与钢桶的倾斜角度。对于锚链，将其等效为悬链线模型，根据风速不同判断锚链的状态，从而求出结果。 ?时能够正常工作。为针对问题二，需要调节重物球的质量，使通讯设备在36m m 了确定重物球的质量，首先将实际风速与临界风速进行比较，判断此时系统中各物体的状态，与题目中已知数据进行比较。在钢桶倾斜角度达到临界角度时，计算锚链与海床的夹角并于题中数据进行比较，计算重物球的质量。在浮标完全没入海面时，计算相应条件下重物球的质量，从而确定满足条件的重物球的质量范围。 针对问题三，要求在不同条件下，求出系泊系统中各物体的状态。以型号I锚链为例，当水流方向与风速方向相同时，系统条件最差，分析在不同水深条件下的系泊系统设计。由题中已知条件确定系统设计的限制条件，对系统各物体进行受力分析，以使整体结果最小，即可得出最优的系泊系统设计。 关键词：悬链线多目标非线性规划 一、问题重述 近浅海观测网的传输节点由浮标系统、系泊系统和水声通讯系统组成（如图1所示）。某型传输节点的浮标系统可简化为底面直径2m、高2m的圆柱体，浮标的质量为1000kg。系泊系统由钢管、钢桶、重物球、电焊锚链和特制的抗拖移锚组成。锚的质量为600kg，锚链选用无档普通链环，近浅海观测网的常用型号及其参数在附表中列出。钢管共4节，每节长度1m，直径为50mm，每节钢管的质量为10kg。要求锚链末端与锚的链接处的切线方向与海床的夹角不超过16度，否则锚会被拖行，致使节点移位丢失。水声通讯系统安装在一个长1m、外径30cm的密封圆柱形钢桶内，设备和钢桶总质量为100kg。钢桶上接第4节钢管，下接电焊锚链。钢桶竖直时，水声通讯设备的工作效果最佳。若钢桶倾斜，则影响设备的工作效果。钢桶的倾斜角度（钢桶与竖直线的夹角）超过5度时，设备的工作效果较差。为了控制钢桶的倾斜角度，钢桶与电焊锚链链接处可悬挂重物球。 系泊系统的设计问题就是确定锚链的型号、长度和重物球的质量，使得浮标的吃水深度和游动区域及钢桶的倾斜角度尽可能小。
Internal Combustion Engine &Parts 0引言 近海系泊系统作为气象监控，海洋探测的主要载体工具，对工程的实际应用有一定的积极作用。为了开发海洋资源，促进经济的发展，满足日益增长的能源需求量，深海油气的开发已成为必然趋势，而系泊系统的设计是深海平台开发的关键问题之一，其设计的目的是保证选择的型号满足工作功能需求，建立相关的代数模型研究在不同情况下的设计方案。 1系泊系统模型 1.1系泊系统平衡模型 忽略作用在锚链上的流动力， 可以将整个锚链简化成悬链线的形式，浮标系统和系泊系统在经过持续海风时浮 标停止运动，系泊系统达到平衡，运用牛顿运动定律和平 行四边形状规则对系统内的各个物体进行受力分析，得到关系表达式为 第一钢管对浮标的拉力为T ，T 与竖直方向多的夹角为θ，浮标所受的浮力为F f ，所受海风荷载为F N ，浮标本身的重力为G ，浮标沉在水中的百分比为α，浮标的直径为d ，沉在水中的高度为h f ，海水的密度为ρ，风速为V ，根据海风荷载近似公式为 求。同时满足轮胎加防滑链极限包络大于 15mm 间隙要求。图3图4Z 向空间 >80mm 图5铆接设计图6铆接设计 ③翼子板下部设计。翼子板下部设计成台阶形。当下部长度>120mm ，需设计成双台阶形（图4），便于两个安装点安装。当翼子板下部刚度不足时，翼子板下部增加下部加强板。翼子板下部设计注意几点：1）翼子板下部加强板材料DC05，料厚为0.7-1.0。2）翼子板下部加强板与翼子板下部安装面打3-5焊点相连。④翼子板后部设计。翼子板后部由于前门总成运动包络影响，翼子板翻边向内小于45度，利于成型。通常安装面设计成台阶形或平 面。翼子板后部安装孔设计圆孔或开口U 形孔，U 形更利于装配。 ⑤翼子板上部设计。 翼子板上部通常安装点采有台阶设计。根据冲压工艺反馈，翻边高度设计为<40mm ，防止出现面品问题。 为满足行人保护要求，通常会从以下几种方式考虑。通常翼子板支架设计成几字形，并在支架两开孔落化（图4）。翼子板上部与边梁高度控制在80mm 以上（图4）。翼子板翻边在满足刚度前提下，尽量开豁口。随着新工艺的发展，翼子板结构，可以采铆接技术，具体设计如图5、6所示。 3制造过程控制 ①翼子板周边件产品要符合设计精度要求。②翼子板过涂装通常有两种方式，一种是在焊装装配 随车身一同电泳，另一种是单件单独电泳。建议采用第一 种，防止总装配出现难调整问题。③总装装配严格按工艺装配相关件。按装配顺序装配完成，再作微调。4结语总之保证翼子板品质，要从设计、制造过程着手。随着 铝合金翼子板、塑料翼子板应用，翼子板设计、制造过程有所变化，但总体设计理念不变。参考文献: [1]袁亮，秦信武，苗布和.汽车前翼子板的布置和结构设计[J].设计研究，2012，04，28. 系泊系统的研究设计 王莎莎;晏明莉 （河南师范大学，新乡453007） 摘要:本文所建立的近海系泊系统模型主要用于研究系泊系统在不同环境下的内在关系，进而给出适应不同情况的设计方案。影 响系泊系统的主要因素分别为锚链的型号，长度和重物球的质量，以及锚链的倾斜角度，浮标的吃水深度和游动区域，通过对系统中各个部分进行受力分析，建立相关的代数模型。该模型通过建立平衡方程组，采用最优控制策略、二分法收敛性和迭代判断，反复迭代计算求解。分别把锚链的型号，长度和重物球的质量作为自变量，把锚链的倾斜角度，浮标的吃水深度和游动区域作为因变量，建立模型进而得出不同环境下系泊系统的设计方案。 关键词:系泊系统设计；最优控制策略；二分法；平衡方程组；迭代计算
系泊系统的设计 摘 要 近浅海观测网的传输节点由浮标系统、系泊系统和水声通讯系统组成，其中系泊系统由钢管、钢桶、重物球及锚链共同组成。此种系泊系统承受风、浪、流的作用及锚链的作用力，运动特性十分复杂。因此，针对海洋环境中水声通讯系统的要求，分析风浪中浮标的动力问题并设计出既安全又经济的系泊系统，对保证水声通讯系统的工作效果来说意义重大。 本文运用了两种方法对锚链进行了受力分析，首先对单一材质的锚链进行分析，从而得出了经典悬链方程，对不同段不同材质的锚链进行分段受力分析，得出了不同段不同材质的悬链方程，该方程的得出极大的方便了计算浮标锚泊系统的初始状态，为动力分析奠定基础；其次利用牛顿法对锚链受力问题进行了数值求解，得到当海面风速为12/m s 加大到24/m s 时，每节钢管的倾斜角度也随之变大，浮标的吃水深度也不断增大，浮标的游动区域增加的更为明显。当风速加大为36/m s 时，钢桶的倾斜角已超过5度，为使钢桶倾斜角小于5度，须将重物球的质量增加至1783kg 。 再考虑风力、水流力、潮汐（波浪）等动力因素时，可以将问题进行简化，即直接考虑在水深18m 的情况下由于波浪的作用（准确的说是2m 波浪的作用），可使整个浮标漂浮于水面上（20m 情形），也可使整个浮标沉于水面下（16m 情形）。最后通过对浮标的受力分析，可得到浮标的动力控制方程，采用数值方法，可以得到在风速为36/m s ，水流速度为1.5/m s 时，倾斜角、吃水深度的数值解。 关键词： 浮标；系统；设计；动力分析
一．问题重述 近浅海观测网的传输节点由浮标系统、系泊系统和水声通讯系统组成（如图1所示）。某型传输节点的浮标系统可简化为底面直径2m、高2m的圆柱体，浮标的质量为1000kg。系泊系统由钢管、钢桶、重物球、电焊锚链和特制的抗拖移锚组成。锚的质量为600kg，锚链选用无档普通链环，近浅海观测网的常用型号及其参数在附表中列出。钢管共4节，每节长度1m，直径为50mm，每节钢管的质量为10kg。要求锚链末端与锚的链接处的切线方向与海床的夹角不超过16度，否则锚会被拖行，致使节点移位丢失。水声通讯系统安装在一个长1m、外径30cm 的密封圆柱形钢桶内，设备和钢桶总质量为100kg。钢桶上接第4节钢管，下接电焊锚链。钢桶竖直时，水声通讯设备的工作效果最佳。若钢桶倾斜，则影响设备的工作效果。钢桶的倾斜角度（钢桶与竖直线的夹角）超过5度时，设备的工作效果较差。为了控制钢桶的倾斜角度，钢桶与电焊锚链链接处可悬挂重物球。系泊系统的设计问题就是确定锚链的型号、长度和重物球的质量，使得浮标的吃水深度和游动区域及钢桶的倾斜角度尽可能小。 问题1某型传输节点选用II型电焊锚链22.05m，选用的重物球的质量为1200kg。现将该型传输节点布放在水深18m、海床平坦、海水密度为1.025×103kg/m3的海域。若海水静止，分别计算海面风速为12m/s和24m/s时钢桶和各节钢管的倾斜角度、锚链形状、浮标的吃水深度和游动区域。 问题2在问题1的假设下，计算海面风速为36m/s时钢桶和各节钢管的倾斜角度、锚链形状和浮标的游动区域。请调节重物球的质量，使得钢桶的倾斜角度不超过5度，锚链在锚点与海床的夹角不超过16度。 问题3 由于潮汐等因素的影响，布放海域的实测水深介于16m20m之间。布放点的海水速度最大可达到1.5m/s、风速最大可达到36m/s。请给出考虑风力、水流力和水深情况下的系泊系统设计，分析不同情况下钢桶、钢管的倾斜角度、锚链形状、浮标的吃水深度和游动区域。 二．模型假设与符号说明 1.模型的假设 由于浮标在海洋受海风、气流、海浪等的作用，气象及水文条件多变，在此，我们对整个问题作适当假设，在下文中，当涉及到具体问题时，我们将有针对性地给出必要的补充。 （1）锚链重力远远大于锚链所受到的流体作用力； （2）海床平坦，无凹凸不平情况； （3）浮标始终是垂直于海平面的，无倾斜或跌倒现象； （4）海面风速均匀、恒定，且风向始终平行于海平面； （5）海水流速均匀（流速与水深无关），且方向恒定（海流无垂直分量）； （6）锚链在整个过程中是不可弹性形变。
数学建模a题系泊系统 设计 集团标准化办公室：[VV986T-J682P28-JP266L8-68PNN]
系泊系统的设计 摘要 本题要求观测近海观测网的组成，建立模型对其中系泊系统进行设计，在不同风速和水流的情况下确定锚链，重物球，钢管及浮标等的状态，从而使通讯设备的工作效果最佳。求解的具体流程如下： 针对问题一，分别对系统中的受力物体在水平方向和竖直方向上的力进行分析，找出锚链对锚无拉力时的临界风速，运用力矩平衡求出钢管与钢桶的倾斜角度。对于锚链，将其等效为悬链线模型，根据风速不同判断锚链的状态，从而求出结果。 ?时能够正常工针对问题二，需要调节重物球的质量，使通讯设备在36m m 作。为了确定重物球的质量，首先将实际风速与临界风速进行比较，判断此时系统中各物体的状态，与题目中已知数据进行比较。在钢桶倾斜角度达到临界角度时，计算锚链与海床的夹角并于题中数据进行比较，计算重物球的质量。在浮标完全没入海面时，计算相应条件下重物球的质量，从而确定满足条件的重物球的质量范围。 针对问题三，要求在不同条件下，求出系泊系统中各物体的状态。以型号I 锚链为例，当水流方向与风速方向相同时，系统条件最差，分析在不同水深条件下的系泊系统设计。由题中已知条件确定系统设计的限制条件，对系统各物体进行受力分析，以使整体结果最小，即可得出最优的系泊系统设计。 关键词：悬链线多目标非线性规划 一、问题重述 近浅海观测网的传输节点由浮标系统、系泊系统和水声通讯系统组成（如图1所示）。某型传输节点的浮标系统可简化为底面直径2m、高2m的圆柱体，浮标的质量为1000kg。系泊系统由钢管、钢桶、重物球、电焊锚链和特制的抗拖移锚组成。锚的质量为600kg，锚链选用无档普通链环，近浅海观测网的常用型号及其参数在附表中列出。钢管共4节，每节长度1m，直径为50mm，每节钢管的质量为10kg。要求锚链末端与锚的链接处的切线方向与海床的夹角不超过16度，否则锚会被拖行，致使节点移位丢失。水声通讯系统安装在一个长1m、外径30cm的密封圆柱形钢桶内，设备和钢桶总质量为100kg。钢桶上接第4节钢管，下接电焊锚链。钢桶竖直时，水声通讯设备的工作效果最佳。若钢桶倾斜，则影响设备的工作效果。钢桶的倾斜角度（钢桶与竖直线的夹角）超过5度时，设备的工作效果较差。为了控制钢桶的倾斜角度，钢桶与电焊锚链链接处可悬挂重物球。
系泊系统的设计 发表时间：2020-01-18T09:59:04.837Z 来源：《基层建设》2019年第28期作者：武佳雷宇张曼[导读] 摘要：系泊系统不论是在船舶航行，还是在海洋资源的综合利用与开发中，均得到了广泛应用，因而，系泊系统的设计问题十分具有现代意义。 华北理工大学数学建模实验室 063000摘要：系泊系统不论是在船舶航行，还是在海洋资源的综合利用与开发中，均得到了广泛应用，因而，系泊系统的设计问题十分具有现代意义。本文隔离系统各组成部分，逐一进行受力分析和力矩分析，构造相应的刚体力学方程组，并根据海水深度联系各参数最终建立系泊系统状态模型。 关键词：系泊系统状态模型；受力平衡；力矩平衡 0引言 当海面风速一定且海水静止时，系泊系统的状态，即钢桶和各节钢管的倾斜角度、锚链形状、浮标的吃水深度和游动区域与系泊系统各部分之间的受力平衡和力矩平衡以及海水深度的约束密切相关。因此，可以隔离该系统的各组成部分，逐一进行力学分析，并最终根据海水深度，联系各参数建立系泊系统状态模型。具体数值参考2016年高教社杯全国大学生数学建模竞赛A题。系泊系统可分为浮标、钢管、钢桶和重物球、锚链四个部分，由题中锚链长度和型号计算得锚链共有210个链环，为了方便表述，对系统内部由上到下的构件进行标记：表1 各构件编号 1力学方程与模型的建立 1.1对浮标的力学分析[1] 漂浮在水面上的浮标，受到来自水平方向的风力、海水对它的浮力、其余组件对它作用力以及自身的重力，与夹角为 。已知浮标的高为，质量为，直径为，海水的密度为，设浮标的吃水深度为，根据重力、浮力公式，以及近海风荷载的近似计 算公式，可得。此时，浮标受到速度为的海风作用在海面上达到平衡，受力分解后，其在水平方向和垂直方向的受力均平衡。于是整理可得关于浮标的完整的刚性力学方程组[2]。其中，其在竖直面的投影高度即为浮标的吃水深度。 1.2对钢管的力学分析没入水中的钢管，由于海水静止，因此忽略水流力水平方向的作用。以与浮标相接的第一节钢管为例，其受到浮标对它的反作用力 、其余组件对它的作用力、海水对它的浮力以及自身的重力。为保持力矩平衡，钢管不发生旋转的现象，浮标对它的反作用力应相对于它的中心轴更偏向竖直方向。 此时有相对于竖直方向的夹角与和的夹角相等，即：，根据牛顿第三定律：。此时，钢管在这些力的共同作用下保持平衡。已知每节钢管的长度为 ，直径为，质量为，根据受力平衡、力矩平衡和重力、浮力公式，可得到相应的刚性力学方程组。其中，其在竖直面的投影高度为。 对于余下的三节钢管，依次进行同样的力学分析。得到对应的完整的刚性力学方程组，以及各钢管在竖直面的投影高度为、 、。 1.3对钢桶和重物球的力学分析没入水中的钢桶和重物球，由于海水静止，则忽略水流力水平方向的作用。对于重物球，其受到钢桶对其的作用力、海水对它的浮 力以及自身的重力。对于钢桶，其受到重物球对其的作用力（方向竖直向下）、其余部件对它的作用力（与竖直方向夹角为 ）和（与夹角为）、海水对它的浮力以及自身的重力.根据牛顿第三定律有。此时，钢桶在这些力的共同作用下保持平衡。已知钢桶的长度为，重物球的质量，设备和钢桶的总质量为，且外径为，根据受力平衡、力矩平衡（注意判断力矩方向）、牛顿第三定律则和阿基米德定律可得到对应的完整的刚性力学方程组。 此时，其在竖直面的投影高度为。 1.4对锚链的力学分析选取编号为的链环，联系该链环以及其上的其余部件构成一个新的整体，对该整体进行受力平衡的分析，其受到海风给它的风力、余下部分给它的拉力、海水给它的浮力以及自身所受的总重力，与水平方向夹角为。通过对整体的分析，简化了作用力与反作用力不断迭代的过程，更加直观的得到受力平衡时的状态。锚链密度为，每节链环的长度和单位长度的质量，再根据前式得到整体所受的总重力，受到海水的总浮力，整理后，可得到关于这个整体的完整的刚性力学方程组。 此时，各链环与竖直方向的夹角即可描述出锚链的形状。各节链环在竖直面的投影高度分别为： 1.5建立系泊系统状态模型 已知水深为，则有