Condition-based Maintenance Optimization for Gamma Deteriorating Systems under Performance-based Contracting

With the further development of service-oriented,performance-based contracting(PBC)has been widely adopted in industry and manufacturing.However,maintenance optimization problems under PBC have not received enough attention.To further extend the scope of PBC’s application in the field of maintenance optimization,we investigate the condition-based maintenance(CBM)optimization for gamma deteriorating systems under PBC.Considering the repairable single-component system subject to the gamma degradation process,this paper proposes a CBM optimization model to maximize the profit and improve system performance at a relatively low cost under PBC.In the proposed CBM model,the first inspection interval has been considered in order to reduce the inspection frequency and the cost rate.Then,a particle swarm algorithm(PSO)and related solution procedure are presented to solve the multiple decision variables in our proposed model.In the end,a numerical example is provided so as to demonstrate the superiority of the presented model.By comparing the proposed policy with the conventional ones,the superiority of our proposed policy is proved,which can bring more profits to providers and improve performance.Sensitivity analysis is conducted in order to research the effect of corrective maintenance cost and time required for corrective maintenance on optimization policy.A comparative study is given to illustrate the necessity of distinguishing the first inspection interval or not.

Performance-based methodology for assessing seismic vulnerability and capacity of buildings

This paper presents a performance-based methodology for the assessment of seismic vulnerability and capacity of buildings. The vulnerability assessment methodology is based on the HAZUS methodology and the improved capacity- demand-diagram method. The spectral displacement (Sd) of performance points on a capacity curve is used to estimate the damage level of a building. The relationship between Sd and peak ground acceleration (PGA) is established, and then a new vulnerability function is expressed in terms of PGA. Furthermore, the expected value of the seismic capacity index (SCev) is provided to estimate the seismic capacity of buildings based on the probability distribution of damage levels and the corresponding seismic capacity index. The results indicate that the proposed vulnerability methodology is able to assess seismic damage of a large number of building stock directly and quickly following an earthquake. The SCev provides an effective index to measure the seismic capacity of buildings and illustrate the relationship between the seismic capacity of buildings and seismic action. The estimated result is compared with damage surveys of the cities of Dujiangyan and Jiangyou in the M8.0 Wenchuan earthquake, revealing that the methodology is acceptable for seismic risk assessment and decision making. The primary reasons for discrepancies between the estimated results and the damage surveys are discussed.

Performance-based seismic design of nonstructural building components:The next frontier of earthquake engineering

With the development and implementation of performance-based earthquake engineering,harmonization of performance levels between structural and nonstructural components becomes vital. Even if the structural components of a building achieve a continuous or immediate occupancy performance level after a seismic event,failure of architectural,mechanical or electrical components can lower the performance level of the entire building system. This reduction in performance caused by the vulnerability of nonstructural components has been observed during recent earthquakes worldwide. Moreover,nonstructural damage has limited the functionality of critical facilities,such as hospitals,following major seismic events. The investment in nonstructural components and building contents is far greater than that of structural components and framing. Therefore,it is not surprising that in many past earthquakes,losses from damage to nonstructural components have exceeded losses from structural damage. Furthermore,the failure of nonstructural components can become a safety hazard or can hamper the safe movement of occupants evacuating buildings,or of rescue workers entering buildings. In comparison to structural components and systems,there is relatively limited information on the seismic design of nonstructural components. Basic research work in this area has been sparse,and the available codes and guidelines are usually,for the most part,based on past experiences,engineering judgment and intuition,rather than on objective experimental and analytical results. Often,design engineers are forced to start almost from square one after each earthquake event: to observe what went wrong and to try to prevent repetitions. This is a consequence of the empirical nature of current seismic regulations and guidelines for nonstructural components. This review paper summarizes current knowledge on the seismic design and analysis of nonstructural building components,identifying major knowledge gaps that will need to be filled by future research. Furthermore,considering recent trends in earthquake engineering,the paper explores how performance-based seismic design might be conceived for nonstructural components,drawing on recent developments made in the field of seismic design and hinting at the specific considerations required for nonstructural components.

The Flemish Performance-based Research Funding System: A Unique Variant of the Norwegian Model

The BOF-key is the performance-based research funding system that is used in Flanders, Belgium. In this paper we describe the historical background of the system, its current design and organization, as well as its effects on the Flemish higher education landscape. The BOFkey in its current form relies on three bibliometric parameters: publications in Web of Science, citations in Web of Science, and publications in a comprehensive regional database for SSH publications. Taken together, the BOF-key forms a unique variant of the Norwegian model: while the system to a large extent relies on a commercial database, it avoids the problem of inadequate coverage of the SSH. Because the bibliometric parameters of the BOF-key are reused in other funding allocation schemes, their overall importance to the Flemish universities is substantial.

Redesigning the Model of Book Evaluation in the Polish Performance-based Research Funding System

Purpose: This study aims to present the key systemic changes in the Polish book evaluation model to focus on the publisher list, as inspired by the Norwegian Model. Design/methodology/approach: In this study we reconstruct the framework of the 2010 and 2018 models of book evaluation in Poland within the performance-based research funding system. Findings: For almost 20 years the book evaluation system in Poland has been based on the verification of various technical criteria(e.g. length of the book). The new 2018 model is based on the principle of prestige inheritance(a book is worth as much as its publisher is) and is inspired by the publisher list used in the Norwegian Model. In this paper, we argue that this solution may be a more balanced policy instrument than the previous 2010 model in which neither the quality of the publisher nor the quality of the book played any role in the evaluation.Research limitations: We work from the framework of the 2018 model of book evaluation specified in the law on higher education and science from 20 July 2018, as implementation acts are not available yet. Practical implications: This study may provide a valuable point of reference on how structural reforms in the research evaluation model were implemented on a country level. The results of this study may be interesting to policy makers, stakeholders and researchers focused on science policy. Originality/value: This is the very first study that presents the new framework of the Polish research evaluation model and policy instruments for scholarly book evaluation. We describe what motivated policy makers to change the book evaluation model, and what arguments were explicitly raised to argue for the new solution.

Performance-based global reliability assessment of a high-rise frame-core tube structure subjected to multi-dimensional stochastic earthquakes

When evaluating the seismic safety and reliability of complex engineering structures,it is a critical problem to reasonably consider the randomness and multi-dimensional nature of ground motions.To this end,a proposed modeling strategy of multi-dimensional stochastic earthquakes is addressed in this study.This improved seismic model has several merits that enable it to better provide seismic analyses of structures.Specifically,at first,the ground motion model is compatible with the design response spectrum.Secondly,the evolutionary power spectrum involved in the model and the design response spectrum are constructed accordingly with sufficient consideration of the correlation between different seismic components.Thirdly,the random function-based dimension-reduction representation is applied,by which seismic modeling is established,with three elementary random variables.Numerical simulations of multi-dimensional stochastic ground motions in a specific design scenario indicate the effectiveness of the proposed modeling strategy.Moreover,the multi-dimensional seismic response and the global reliability of a high-rise frame-core tube structure is discussed in detail to further illustrate the engineering applicability of the proposed method.The analytical investigations demonstrate that the suggested stochastic model of multi-dimensional ground motion is available for accurate seismic response analysis and dynamic reliability assessment of complex engineering structures for performance-based seismic resistance design.

Optimization for performance-based design under seismic demands, including social costs

Performance-based design in earthquake engineering is a structural optimization problem that has, as the objective, the determination of design parameters for the minimization of total costs, while at the same time satisfying minimum reliability levels for the specifi ed performance criteria. Total costs include those for construction and structural damage repairs, those associated with non-structural components and the social costs of economic losses, injuries and fatalities. This paper presents a general framework to approach this problem, using a numerical optimization strategy and incorporating the use of neural networks for the evaluation of dynamic responses and the reliability levels achieved for a given set of design parameters. The strategy is applied to an example of a three-story offi ce building. The results show the importance of considering the social costs, and the optimum failure probabilities when minimum reliability constraints are not taken into account.

Performance-based concept on seismic evaluation of existing bridges

Conventional seismic evaluation of existing bridges explores the ability of a bridge to survive under significant earthquake excitations. This approach has several major drawbacks, such as only a single structural performance of near collapse is considered, and the simplified approach of adopting strength-based concept to indirectly estimate the nonlinear behavior of a structure lacks accuracy. As a result, performance-based concepts that include a wider variety of structural performance states of a given bridge excited by different levels of earthquake intensity is needed by the engineering community. This paper introduces an improved process for the seismic evaluation of existing bridges. The relationship between the overall structural performance and earthquakes with varying levels of peak ground acceleration （PGA） can successfully be linked. A universal perspective on the seismic evaluation of bridges over their entire life-cycle can be easily obtained to investigate multiple performance objectives. The accuracy of the proposed method, based on pushover analysis, is proven in a case study that compares the results from the proposed procedure with additional nonlinear time history analyses.

Peak displacement patterns for the performance-based seismic design of steel eccentrically braced frames

Performance-based seismic design(PBSD) aims to assess structures at different damage states. Since damage can be directly associated to displacements, seismic design with consideration of displacement seems to be logical. In this study, simple formulae to estimate the peak floor displacement patterns of eccentrically braced frames(EBFs) at different performance levels subjected to earthquake ground motions are proposed. These formulae are applicable in a PBSD and especially in direct displacement-based design(DDBD). Parametric study is conducted on a group of 30 EBFs under a set of 15 far field and near field accelerograms which they scaled to different amplitudes to adapt various performance levels. The results of thousands of nonlinear dynamic analyses of EBFs have been post-processed by nonlinear regression analysis in order to recognize the major parameters that influence the peak displacement pattern of these frames. Results show that suggested displacement patterns have relatively good agreement with those acquired by an exact nonlinear dynamic analysis.

Persisting challenges for performance-based building assessment

Intense research and refinement of the tools used in performance-based seismic engineering have been made,but the maturity and accuracy of these methods have not been adequately confirmed with actual data from the field. The gap between the assumed characteristics of actual building systems and their idealized counterparts used for analysis is wide. When the randomly distributed flaws in buildings as they exist in urban areas and the extreme variability of ground motion patterns combine,the conventional procedures used for pushover or dynamic response history analyses seem to fall short of reconciling the differences between calculated and observed damage. For emergency planning and loss modeling purposes,such discrepancies are factors that must be borne in mind. Two relevant examples are provided herein. These examples demonstrate that consensus-based analytical guidelines also require well-idealized building models that do not lend themselves to reasonably manageable representations from field data. As a corollary,loss modeling techniques,e.g.,used for insurance purposes,must undergo further development and improvement.

Probabilistic Performance-Based Optimum Seismic Design Framework: Illustration and Validation

In the field of earthquake engineering,the advent of the performance-based design philosophy,together with the highly uncertain nature of earthquake ground excitations to structures,has brought probabilistic performance-based design to the forefront of seismic design.In order to design structures that explicitly satisfy probabilistic performance criteria,a probabilistic performance-based optimum seismic design(PPBOSD)framework is proposed in this paper by extending the state-of-the-art performance-based earthquake engineering(PBEE)methodology.PBEE is traditionally used for risk evaluation of existing or newly designed structural systems,thus referred to herein as forward PBEE analysis.In contrast,its use for design purposes is limited because design is essentially a more challenging inverse problem.To address this challenge,a decision-making layer is wrapped around the forward PBEE analysis procedure for computer-aided optimum structural design/retrofit accounting for various sources of uncertainty.In this paper,the framework is illustrated and validated using a proof-of-concept problem,namely tuning a simplified nonlinear inelastic single-degreeof-freedom(SDOF)model of a bridge to achieve a target probabilistic loss hazard curve.For this purpose,first the forward PBEE analysis is presented in conjunction with the multilayer Monte Carlo simulation method to estimate the total loss hazard curve efficiently,followed by a sensitivity study to investigate the effects of system(design)parameters on the probabilistic seismic performance of the bridge.The proposed PPBOSD framework is validated by successfully tuning the system parameters of the structure rated for a target probabilistic seismic loss hazard curve.The PPBOSD framework provides a tool that is essential to develop,calibrate and validate simplified probabilistic performance-based design procedures.

Performance-Based Design through Implementation of FEMA P-58 Methodology in Developing Countries

This paper investigates a simple approach proposed towards performance-based earthquake engineering (PBEE) which has potential applications to the performance-based design (PBD) and performance-based assessment (PBA) fields. The simple method of PBEE encompasses three areas of seismic risk which include seismic hazard, structural analysis, and loss models. The aim of the PBEE process, entitled as FEMA P-58, is to present essential data needed to make a rational decision regarding predicted performance, where various sources of uncertainties are involved. In developing countries, the lack of suitable real ground motions corresponding to site characteristics and seismicity particularly for larger intensities and the scarcity of demands, which makes it hard to identify the seismic capacity of a structure, is the main our motivation of using the FEMA method. In this paper, the method of FEMA P-58 is investigated, in terms of available tools and required data, in such a way that it will be applicable for developing countries which are located in high seismic hazard zones. To achieve this goal, three steel moment-resisting buildings with low and high ductility, and three steel braced-frame buildings are selected as case studies. The mean annual loss is estimated by the available software, Performance Assessment Calculation Tool (PACT). The achieved results, i.e. the loss curves, will provide a simple means by which the engineers can quantify and communicate seismic performance to other stakeholders. In the case study buildings, the braced one has less annual losses in comparison with other investigated cases, and the structure with high ductility can be considered as the next ones. Execution cost of each building should be considered by contractors. Also, seismic fragility curves of structures for various limit states, as well, the corresponding loss models are identified as the most essential data towards application of the investigated PBEE process.

Research on performance-based seismic design criteria

The seismic design criterion adopted in the existing seismic design codes is reviewed. It is pointed out that the presently used seismic design criterion is not satisfied with the requirements of nowadays social and economic development. A new performance-based seismic design criterion that is composed of three components is presented in this paper. It can not only effectively control the economic losses and casualty, but also ensure the building's function in proper operation during earthquakes. The three components are: classification of seismic design for buildings, determination of seismic design intensity and/or seismic design ground motion for controlling seismic economic losses and casualties, and determination of the importance factors in terms of service periods of buildings. For controlling the seismic human losses, the idea of socially acceptable casualty level is presented and the 'Optimal Economic Decision Model' and 'Optimal Safe Decision Model' are established. Finally, a new method is recommended for calculating the importance factors of structures by adjusting structures service period on the base of more important structure with longer service period than the conventional ones. Therefore, the more important structure with longer service periods will be designed for higher seismic loads, in case the exceedance probability of seismic hazard in different service period is same.

Linking Real-Life Situations with Classroom Assessment: Development of Real-Life Performance-Based Tasks in Business Mathematics

This study aimed to develop real-life performance-based tasks in Business Mathematics (RLPBTs) following the ADDIE’s model of instructional development. Using the descriptive-developmental research design, the study developed RLPBTS with mathematics experts, mathematics department head, bank manager, mathematics teachers, and students as respondents. The RLPBTs consist of instructional plans. Each instructional plan has these components: Introduction, Learning Competency, Learning Outcome, Task Execution, Scoring Guide, and Generalization. The design and content of the instructional plans were assessed as very good. On the other hand, the design and execution of the Tasks were assessed as favorable. Grade 11 students also agreed that real-life performance-based tasks helped them understand better concepts in business mathematics. They claimed that they enjoyed the tasks because of the inclusion of real-life situations that they simulated. The use of the RLPBTs provides another innovation in the teaching and learning concepts in Business Mathematics.

Development of Performance-Based Tunnel Evaluation Methodology and Performance Evaluation of Existing Railway Tunnels

The concept of performance-based design, which mainly focuses on mechanical performance, has become the international standard, as in the case for ISO. The standardization of tunnel design has not been achieved because it requires integration of separate specialized fields, such as geotechnical engineering, structural engineering and concrete engineering. It is also required to clarify performance-based criteria for tunnel structures to suit specific use purposes (objectives), establish the concept of survey, planning, design, construction and maintenance based on such criteria, and develop proper management systems for operation and maintenance to suit specific tunnel use purposes. To this end, it is vital to develop a methodology for evaluating and verifying the performance of existing tunnels. This paper presents a new concept of performance requirements for tunnel structures and describes the method of quantitatively evaluating the total performance of existing tunnels in relation to the required performance, assuming the total performance to be based on the Analysis Hierarchy Process.

数字金融与商业银行审计费用

以2011—2021年中国商业银行为研究对象,探究数字金融对审计费用的影响机理与传导效应。研究发现:数字金融发展初期会增加商业银行的审计费用,当数字金融发展到一定水平后,金融科技增强带来的审计费用下降效应会超过因审计投入和审计风险提升的审计费用上升效应,进而降低商业银行的审计费用,说明数字金融与审计费用之间呈先扬后抑的倒U形关系。机制检验发现,数字金融主要通过作用于代理冲突和信息不对称导致审计风险与成本变动,最终影响审计费用。异质性分析显示,审计主体来自国内四大审计事务所时,数字金融对审计费用的非线性作用增强;审计客体是上市银行与资本充足率较高的商业银行时,数字技术能更有效地对审计费用产生非线性效应;商业银行在市场化程度和法律水平较高、数字金融监管较严的地区时,数字金融与审计费用的倒U形关系更显著。研究结论从审计费用角度丰富了数字金融经济后果研究,为商业银行实施数字化转型战略、注册会计师审计收费决策提供参考。

隐性关联关系与审计费用——基于供应链工商大数据的研究

近年来,上市公司将其供应链商业关系隐藏化以规避信息披露要求的趋势越来越明显,不利于投资者评估和判断上市公司的交易性质和盈利能力。本文从审计师角度出发,以2010-2021年度我国A股上市公司为研究对象,基于供应链工商大数据度量隐性关联关系,分析隐性关联关系与审计费用之间的关系,结果发现上市公司与重要交易对象之间存在隐性关联关系提高了审计费用,一系列稳健性检验结果保持一致。在渠道检验中,研究发现隐性关联关系通过影响审计师投入,进一步影响审计费用。在分组检验中,研究发现隐性关联关系对审计费用的影响在高市场化进程地区、低信息透明度的公司以及当上市公司为事务所重要客户时更为显著。本文研究为审计师如何判断隐性关联关系问题提供了经验数据。

减税降费对企业投资效率的影响研究

减税降费政策是促进企业发展、提高市场活力的重要举措,对提高企业投资效率、推进供给侧改革具有重要意义。本文通过我国沪深A股上市公司2012-2020年的数据,对减税降费对企业投资效率的影响进行研究。研究结果表明:减税降费能够有效提升企业的投资效率;机制检验表明,减税降费可以通过缓解融资约束,减少企业投资不足的行为,通过降低信息不对称程度抑制过度投资的行为。通过进一步研究发现,减税降费对提高民营企业、低自由现金流企业投资效率的效果更为显著;政策对不同成长机会的企业影响效应有所区别;政策对市场化程度较高地区的企业投资不足的作用更加明显,而对市场化程度较低地区的企业过度投资的作用更为明显。本文还提出了推进减税降费政策,从而提高企业投资效率、促进企业高质量发展的政策建议。

公共图书馆非基本服务项目收费的现实需求、困境与对策

非基本服务项目收费是推动公共图书馆社会化发展的重要举措。虽然公共图书馆非基本服务项目收费在我国有着强烈的现实需求和法律政策依据,但实践中面临着诸多困境,主要表现为:非基本服务项目收费的法律政策不够完善,收费行为影响基本服务项目的高质量供给,收费审批程序、定价和用途较为随意,容易形成“以文养文”的局面。解决之道包括:完善非基本服务项目的收费政策,加强政府的主体保障责任,规范收费审批程序、定价及用途。参考文献19。

企业信息安全对审计决策的影响

在国家安全战略背景下,确保企业信息安全,维护企业经营的安全性、稳定性和连续性显得尤为重要。外部审计师是否能够识别企业信息安全,并对企业强化信息安全提供助力?本文以我国2013-2021年A股上市公司为样本,从审计费用的角度检验审计师对企业信息安全的反应,发现企业信息安全能够降低企业的审计费用。机制检验发现,企业信息安全通过缓解企业的经营风险进而降低审计费用。进一步研究发现,当企业的关键信息基础设施安全保护需求较高以及独董信息技术背景比例较高时,企业信息安全对审计费用的影响更加显著。本研究丰富了企业信息安全和审计费用的相关文献,有助于了解企业信息安全对审计师决策的影响,为上市公司加强信息安全建设提供了经验证据。