Supporting the decision-making process for sustainable housing

Wide acceptance of the concept of sustainable development has led to a demand for policies on sustainable housing. The issues of how sustainable housing can be measured or evaluated and how decision-making regarding sustainable housing can be facilitated are areas that require further research. This paper aims to introduce a conceptual approach in developing a decision-support tool for sustainable housing. An empirical decision-support model for sustainable housing indicators using fuzzy-set theory (SHIFT) is described, with particular focus on framing decision-making for multiple criteria or objectives.     

A decision model proposal for construction contractor selection in Turkey

This study proposes a multi-criteria decision model for construction contractor selection in the Turkish public sector. Current selection methods are reviewed and three main concepts are generated for selection: cost, time, and quality. The proposed selection model uses evaluation criteria related to these concepts and has a process with two main stages: contractor prequalification and the choice of the eligible (compromised) bidder among prequalified contractors. This model can be used as a decision support system by project owners in order to identify an eligible contractor to be awarded the contract.     

GA-based decision support system for housing condition assessment and refurbishment strategies

Refurbishment work involves improvement, upgrading, renovation, retrofit, and repair of existing housing. With limited land usage and being aware of sustainability, the refurbishment market has faced increasing needs worldwide. During the long life cycle period of housing, most residents are undoubtedly faced with refurbishment requirements. However, it is not easy to make assessment and refurbishment related decisions due to the lack of knowledge and experience. This study presents Genetic algorithm-based on-line decision support system (DSS) to help residents easily conduct the housing condition assessment and offers optimal refurbishment actions considering the trade-off between cost and quality. Two refurbishment models are developed to explore the relationship among the life cycle cost, restoration cost and improved quality. The result reveals the proposed DSS solves the problems arising from asymmetric information and conflicting interests between residents and contractors, as well as improves traditional housing condition assessment to be more effective and efficient.     

Multivariant design and multiple criteria analysis of building refurbishments

In order to design and realize an efficient building refurbishment, it is necessary to carry out an exhaustive investigation of all solutions that form it. The efficiency level of the considered building's refurbishment depends on a great many of factors, including: cost of refurbishment, annual fuel economy after refurbishment, tentative pay-back time, harmfulness to health of the materials used, aesthetics, maintenance properties, functionality, comfort, sound insulation and longevity, etc. Solutions of an alternative character allow for a more rational and realistic assessment of economic, ecological, legislative, climatic, social and political conditions, traditions and for better the satisfaction of customer requirements. They also enable one to cut down on refurbishment costs. In carrying out the multivariant design and multiple criteria analysis of a building refurbishment much data was processed and evaluated. Feasible alternatives could be as many as 100,000. How to perform a multivariant design and multiple criteria analysis of alternate alternatives based on the enormous amount of information became the problem. Method of multivariant design and multiple criteria of a building refurbishment's analysis were developed by the authors to solve the above problems. In order to demonstrate the developed method, a practical example is presented in this paper.     

深圳湾体育中心项目工程施工总承包管理实践

施工总承包管理模式已经成为我国大型建设项目的主流模式,随着业主对大型建设项目的工期、质量、安全等要求和期望越来越高,施工标段和分包单位越来越多,导致施工总承包管理难度不断加大.文中通过深圳湾体育中心大型建设项目实例,从管理理念和原则、管理组织机构以及总承包管理等方面系统地介绍了该项目施工总承包管理经验,供同行参考.     

Energetische Sanierung von Schulgebäuden in den neuen Bundesländern – Sanierungsprojekt Förderschule Rathenow

Energy efficiency improvements for school buildings in Germany's new federal states; Rathenow special school refurbishment project. Current energy saving measures for existing buildings focus on refurbishment of schools and other educational buildings. The building described in this article represents the standard type of a large‐panel construction series in the new federal states. Due to the large number of buildings (540) constructed in this way the project can act as a model for similar projects. Initial studies indicated that structural refurbishment measures for these buildings are required as a matter or urgency. The energy performance calculations for the building showed good agreement between the calculated demand values and actual heating energy consumption values and can serve as basis for predictions of energy savings through various refurbishment measures. The new DIN 18599 calculation standard enables significantly more differentiated consideration of boundary conditions such as occupied periods, occupancy levels, internal heat sources, and the effect of night setback. Based on comparative calculations, different refurbishment concepts can be developed and assessed.     

A multiple kernel learning-based decision support model for contractor pre-qualification

Due to the complex nature of the contractor pre-qualification such as subjectivity, non-linearity and multi-criteria, advanced model should be required for achieving a high accuracy of this decision-making process. Previous studies have been conducted to build up quantitative decision models for contractor pre-qualification, among them artificial neural network (ANN) and support vector machine (SVM) have been proved to be desirable in solving the pre-qualification problem with regards to their higher accuracy and efficiency for solving the non-linear problem of classification. Based on the algorithm of SVM, multiple kernel learning (MKL) method was developed and it has been proved to perform better than SVM in other areas. Hence, MKL is proposed in this research, the capability of MKL was compared with SVM through a case study. From the result, it has been proved that both SVM and MKL perform well in classification, and MKL is more preferable than SVM, with a proper parameter setting. Therefore, MKL can enhance the decision making of contractor pre-qualification.     

Final contractor selection using the analytical hierarchy process

Some contractor selection methods currently in existence are criticized as incomplete and biased, and lacking consideration in terms of the contractor's ability to achieve simultaneously, time, cost, quality and safety standards. This research examines an alternative contractor selection model called the analytical hierarchy process (AHP), which will help construction clients to identify contractors with the best potential to deliver satisfactory outcomes in a final contractor selection process which is not based simply on the lowest bid. The AHP comprises three parts: hierarchic structure, prioritization procedure, and calculation of results. This model is tested by a hypothetical scenario where three contractor candidates are evaluated. The criteria used for contractor selection in the model have been identified, and the significance of each criterion has been arrived at by conducting a questionnaire survey in public organizations in Hong Kong. Comparisons are made by ranking the aggregate scores of each candidate with regard to their performance against each of the criteria, and the candidate associated with the highest scores is the best contractor on this occasion.     

Optimal pricing and environmental improvement for a hazardous waste disposal supply chain with emission penalties

Hazardous waste management has become a municipal problem, associated with industrial development and changing consumption patterns. We study the hazardous waste management system as a supply chain with a disposal facility and a contractor, which serves customers with demand sensitive to price and environment impact. The government intervenes with this supply chain by imposing emission penalties that make the waste disposal facility responsible for reducing disposal process emissions. The Stackelberg game and Nash equilibrium are used to model the decision-making sequence between the disposal facility and the contractor. We specify different scenarios to model the hazardous waste management supply chain. The goal of this research is to find the optimal disposal service price and level of environmental improvement to mitigate adverse impacts and maximize profits. The applicability of dual-channel service in the hazardous waste supply chain is also investigated. Our study shows that the supply chain obtains the highest profit if both the disposal facility and the contractor operate in a centralized model. Under some scenarios, profitability improves if the disposal facility becomes active in waste collection and transportation under a dual-channel supply-chain model. Demand sensitivity to price and environmental impacts can affect the adopted level of improvement by disposal facilities.     

代建制实施中合谋行为的博弈分析和监管机制设计

基于代建人可能寻租的动机假设,通过分析代建制实施中合谋行为产生的机理,揭示了代建制实施中合谋体的类型和合谋发生的供需耦合、制度空间和社会背景原因。构建了政府、政府主管部门、代建人、承包商四者之间的博弈模型并进行了求解,得到了各方参与合谋的条件,并分析了在不同惩罚系数情况下合谋产生的条件差异,识别出防范合谋的关键政策变量。在此基础上,提出了防范代建制实施中合谋行为的机制设计建议。     

基于建筑供应链管理的工程采购数量弹性契约研究

建筑业采用集成式的供应链管理是降低建设工程成本的重要方法。为解决传统工程采购模式存在的合作度低、采购效率低下、对不确定性的应变能力差等缺陷。对比了建筑供应链管理环境下与传统工程采购模式的特点，基于供应链契约理论，构建了承包商与供应商之间的数量弹性采购契约模型，并证明了该契约模式可以有效应对工程采购中需求的不确定性。结论表明，建筑供应链管理下的数量弹性采购契约模式可以使承包商灵活地进行特定的采购活动，进而使建筑供应链上下游企业在一定程度上达到协调。     

The factors influencing bid mark-up decisions of large- and medium-size contractors in Singapore

The construction industry in Singapore is dominated by a competitive business environment that is being driven by a lowest cost mentality. The pressure on contractors' profit margins has further increased after a prolonged recession in this sector, which has seen construction demand and output shrinking significantly. This paper examines the factors that contractors perceive to be important when they are considering the size of their bid mark-up. The research hypothesis is that contractor size would have a significant bearing on the factors that would influence the bid mark-up decision. Forty factors were identified and a survey was conducted. The results showed that contractor size has a significant impact on their attitude towards bid mark-up decision-making. The analysis also showed that when deciding the size of a bid mark-up large contractors tend to be more concerned with the nature of the construction work while medium-size contractors are more concerned about the state of their own companies finance.     

A fuzzy neural network approach for contractor prequalification

Non-linearity, uncertainty and subjectivity are the three predominant characteristics of contractors prequalification which lead to the process being more of an art than a scientific evaluation. A fuzzy neural network (FNN) model, amalgamating both the fuzzy set and neural network theories, has been developed aiming to improve the objectiveness of contractor prequalification. Through FNN theory, the fuzzy rules as used by the prequalifiers can be identified and the corresponding membership functions can be transformed. Eightyfive cases with detailed decision criteria and rules for prequalifying Hong Kong civil engineering contractors were collected. These cases were used for training (calibrating) and testing the FNN model. The performance of the FNN model was compared with the original results produced by the prequalifiers and those generated by the general feedforward neural network (GFNN, i.e. a crisp neural network) approach. Contractors' ranking orders, the model efficiency (R²) and the mean absolute percentage error (MAPE) were examined during the testing phase. These results indicate the applicability of the neural network approach for contractor prequalification and the benefits of the FNN model over the GFNN model. The fuzzy neural network is a practical approach for modelling contractor prequalification.     

A contractor pre-qualification model based on the quality function deployment method

Contractors play a significant role in construction projects and selection of the most appropriate contractor for the project is a critical decision for clients. The pre-qualification of construction contractors is accounted as a very important step in contractor selection for every project. The main purpose of pre-qualification is to identify an array of eligible contractors, which is required for post-qualification steps and further considerations. Although there have been numerous models for contractor pre-qualification, there are inadequate researches to present a contractor pre-qualification model with consideration of the project objectives or the project owner’s requirements. A new contractor pre-qualification model was developed with the aim of resolving this issue. This model employs the quality function deployment (QFD) method, and considers both the project owner’s requirements and the contractor’s abilities. The results reveal that consideration of the project objectives or the project owner’s requirements and expectations can influence contractor pre-qualification.     

An integration of the fuzzy reasoning technique and the fuzzy optimization method in construction project management decision-making

Most real world decision-making combines quantitative and qualitative (linguistic) variables. Conventional mathematics that combines qualitative and quantitative concepts exhibits difficulty in modelling actual problems. The research presented in this paper illustrates a mathematical approach to the solution of decision-making problems that combine qualitative and quantitative objectives. A methodical system for construction project management decision-making was developed using a combination of fuzzy multiple-objective decision-making theory and the fuzzy reasoning technique. The mathematical model can be applied to construction project management problems by suggesting an optimal path of corporate cash flow that results in the minimum use of resources. The information provided by the mathematical model allows the planner to eliminate excess use, or idleness, of resources during the construction of a project. Such information is indispensable for decision-makers in analysing the best time to invest in a new project. A case study is demonstrated to illustrate the application to a management decision problem.     

基于三维矩阵模型的EPC 总承包能力评价研究

随着“一带一路”倡议的提出和国内建筑业深化改革的推进,EPC总承包模式成为我国建筑企业“走出去”及国内工程建设组织模式发展的主要方向。为提升我国建筑企业EPC总承包能力,以应对国内外EPC市场的机遇与挑战,从市场需求和企业发展的角度,分析了新时期建筑企业EPC总承包能力的内涵,并对能力层级进行划分,从产业链视角分析识别工程总承包能力的影响因素,基于能力层级对影响因素的能力特性进行划分,在此基础上提出三维矩阵能力评价模型;运用实例分析验证了评价模型的有效性,以期为提高工程总包商工程总承包能力提供参考。     

合同付款条件对国际工程项目承包商财务状况的影响

合同付款条件对国际工程项目承包商财务具有重要影响。尽管承包商能够定性识别合同付款条件是否对本方有利,但并不能仅凭定性判断而获知其对资金压力和盈利水平的具体影响。为帮助承包商在合同谈判中能正确决策合同付款条件,在分析国际工程项目合同付款条件内容与性质的基础上,提出了定量分析合同付款条件对承包商现金流和财务影响的模型。以非洲某EPC 道路工程为案例,假设了不同进度付款方式和预付款比例所构成的6 种合同付款条件组合,分析了合同付款条件对现金流入、现金支出、垫资成本和盈利水平的影响,识别了不可接受的合同付款条件,为承包商正确决策提供了支持。     

Developing and implementing environmental management systems for small and medium-sized construction enterprises

Environmental aspects are gradually becoming factors of importance for construction businesses, their operations and their management. These factors can be seen as new change makers for construction management itself. New criteria need to be taken into account when structuring construction activities, in decision making, and throughout the production control. Instances of construction management solutions that also encapsulate environmental aspects are likely to appear. A contractor’s environmental management system (EMS) is an example of such an instance. As a management solution an EMS is targeted at minimizing a contractor’s environmental impacts. An experiment has been carried out where an EMS solution was formed and tested for small and medium-sized contractors. Fifteen small and medium-sized construction companies were involved. Along with the action research approach, a set of workshops with company people were arranged for EMS structuring and for its testing. Within these experiments the researcher acted as a developer and inside observer. The proposed EMS solution presents the structuring of environmental aspects for management attention. Moreover, this structuring can be used as a basis for a formal environmentally conscious management system. All companies involved in the research have started to use the EMS solution or its parts.     

工程量清单计价模式下总承包服务费编制研究

随着工程项目规模的逐渐扩大,以及各个专业分工逐渐精细化,施工总承包方式逐渐成为建设施工项目中所采用的主要方式,而总承包服务费则成为其讨论的重点。在GB 50500-2013《建设工程工程量清单计价规范》中对总承包服务费的概念、内容以及计取方面都有了一定的调整和修改,但仍然没有对总承包服务费编制过程中的重难点做详细的分析和规定。因此,文章在对总承包服务费的内涵及其包含的三种费用进行剖析,进而对总承包服务费的计价进行分析,并给出总承包服务费的编制要点,最后通过案例分析进行了验证。以期通过对总承包服务编制问题的研究,有助于提高GB 50500-2013《建设工程工程量清单计价规范》的适用性。