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.

Hourly Wage and the Likelihood of Stealing an Item

Researchers have extensively explored the impact of wages on individuals’ decisions to engage in property crimes. While most of these studies in the past have relied on macro-level data to investigate the relationship between crime rates and hourly wages, this paper takes a novel approach by utilizing micro-level data to examine the influence of hourly wages on the likelihood of stealing an item valued at least $50. The results obtained from the estimations reveal that an increase in hourly wage leads to a decrease in the probability of theft, all other factors being held constant. Further estimation by gender revealed that hourly wages given to both male and female have no bearing on the decision to steal. Additionally, the analysis of the differences in theft probabilities across gender and race demonstrates that males consistently exhibit a higher likelihood of engaging in theft when compared to females across various racial groups.

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.

A case study of performance-based pavement maintenance and rehabilitation needs assessment in Pennsylvania

This paper presents the theory,method,and application of performance-based pavement needs assessment at a state level,using the Pennsylvania Interstate System as an example.First,a general framework is presented for the pavement asset management and a general optimization model is established for the pavement maintenance and rehabilitation needs assessment.Also,the bundling of pavement segments for the project implementation is discussed.Using the examples of Statewide Transportation Improvement Plan and Long Range Transportation Plan for Pennsylvania Interstate System,the application of performance-based pavement needs assessment is demonstrated.It is shown that unconstrained analysis can help decision-makers investigate the real maintenance and rehabilitation needs;financially-constrained analysis can help decision-makers select projects for implementation and examine the corresponding future pavement conditions.Trade-off analysis can help decision-makers investigate the outcomes of different investment levels on pavement maintenance and rehabilitation and make the final decision on the investment level.The proposed case study provides a good example of performance-based pavement needs assessment for developing countries.

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.

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.

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 seismic financial risk assessment of reinforced concrete frame structures

Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.

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.

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.

The Effects of Greenhouse Gases Regulation on Wages and Rents: Policy Issues and General Equilibrium Analysis

The stringency of environmental policy is likely to change the gains of economic agents. Using a general equilibrium model and an assumption that capital-intensive industries tend to be intensive emitters of greenhouse gases (GHG), we find that a stricter GHG emission scheme will reduce the rent for capital owners but increase the wage for workers. This effect could motivate capital owners or workers to oppose or support a stricter GHG policy. The paper also empirically assesses the model’s key assumption by using production input (capital stock and labor), output, and GHG emission data from U.S industrial sectors. The regression result supports a strong positive relationship between the capital-labor ratio and the pollution-output ratio. Therefore, the theoretical analysis is relevant to the actual economy.

Wages and Salaries of Czech Men and Women at the Beginning of the Third Millennium and the Impact of the Economical Recession on Their Development

This paper deals with the development of the wage distribution in the Czech Republic since 2003, according to gender. It is a development of descriptive characteristics of location, differentiation and shape of wage distribution, but also the development of concentration characteristic of wage distribution. Gross monthly wage of Czech employees represents the variable under research. Emphasis is placed on changes in the development of wage distribution since 2009 in connection with the onset of economic recession. The economic crisis has greatly influenced the development of the wage distribution in the Czech Republic, wage growth virtually stopped at this time. Differences in the development of wage distribution between men and women in the Czech Republic are also under this research. Development of wage distribution has been studied by modelling the distribution. Three-parametric lognormal curves are served as a theoretical probability distribution whose parameters were estimated using the L-moment method of point estimate of parameters. Dependence of gross monthly wage on gender has been the subject of research as well. This dependence was researched using one-way analysis of variance. Forecast of wage distribution of men and women in the Czech Republic for the years 2012 and 2013 is included in this research.

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.

Determinants of Wages and Labour Supply in the UK

We explore characteristics of the UK labour market with special emphasis on explanation of the existing wage inequalities, determinants of participation, and variation in the magnitude of hours of labour supplied among individuals. We explain up to 92 percent of variance in the wage rates from the supply side. Accuracy of the model is accounted by a variety of factors relevant to the labour market such as gender gaps, marital status, on and off the job training, fluency in English, and regional characteristics. The study is quite distinct, since it not only incorporates variables pertinent from the economic point of view, but also some quantified qualitative regressors relating to individuals’ opinions and political preferences. Interestingly, we find that the psychological profile of an individual has a very big influence over his decision on whether to participate, but once he joined the labour force his personal beliefs and opinions have no further impact on the probability of finding a job. The chance of being employed once participating depends mainly on the local labour market conditions. We also report unbiased and reliable estimate of labour supply elasticity based on British Household Panel Survey （BHPS） sample.

Impact of Prevailing Wages on the Cost among the Various Construction Trades

In 1997, the Ohio Senate passed Senate Bill 102 which established the Ohio School Facilities Commission as a separate agency to oversee the rebuilding projects of the public schools in Ohio. The bill also exempted the construction contractors from paying prevailing wages on these projects on the hypothesis that this exemption would lower the construction cost. The purpose of this study is to investigate this hypothesis through the statistical analysis of 8,093 bids received from the years 2000 through 2007 for the schools＇ construction. Union contractors who paid their workers union wages and non-union contractors who did not pay prevailing wages bid these projects. The hypothesis, that prevailing wage laws increased the construction cost, was tested by comparing the bids/SF （square foot） from both groups （union and nonunion） for the different construction trades. The study indicated that there was statistical significant difference between the bids/square foot for union contractors and the bids/square foot for non-union contractors for only the following trades： earthwork, existing conditions, plumbing, electrical and HVAC （heating, ventilation and air conditioning）. The averages of bids/SF from the union contractors were higher than those from the non-union contractors for earthwork, existing conditions and plumbing works, and the opposite for electrical and HVAC works. There was no statistical significant difference in the bids from the communications, concrete, conveying equipment, electronic safety and security, equipment, finishes, fire suppression, furnishings, masonry, openings, structural steel, thermal and moisture protection, plastics and composites and wood works.

Real Interest Rates,Real Wages and Economic Restructuring—Analysis Based on Dynamic Stochastic General Equilibrium(DSGE)

On the basis of research conducted by Long and Plosser(1983),this paper carries out an in-depth analysis on the relationship between real interest rates,real wage,and macro-economy and economic structure by simulating a dynamic stochastic general equilibrium(DSGE) model and comes to the following conclusions:(1) Increasing the level of real interest rates will expand the share of consumption in GDP,improve the macroeconomic structure,and promote steady economic development;(2) Increasing the level of real wages will enhance economic growth but will not change the economic structure of consumption and investments;(3) Increasing wages will enhance economic growth and expand its share in national income;(4) Increasing wages will not lower output level but will be favorable to the improvement of economic structure.Therefore,this paper argues for interest rates liberalization to achieve long-term,steady economic development in China.