Blockchain-based smart contract for smart payment in construction: A focus on the payment freezing and disbursement cycle

Late payment, and indeed no payment, is a rampant and chronic problem that has plagued the global construction industry for too long. Recent development in blockchain technology, particularly its smart contract, seems to provide a new opportunity to improve this old problem. However, this opportunity is largely unexploited. This study aims to develop a blockchain-based smart contract (BBSC) system for smart payment in the construction industry by focusing on the fundamental cycle of payment freezing (sometimes also synonymously called payment guarantees) and disbursement application. Firstly, a BBSC framework, containing three processes of (a) initiation and configuration, (b) payment freezing, and (c) disbursement application, is developed. Next, based on the framework, the system architecture of the BBSC system, containing three layers of (1) Infrastructure as a Service (IaaS), (2) Blockchain as a Service (BaaS), and (3) Software as a Service (SaaS) is proposed and elabora-ted. Finally, based on the system architecture, a BBSC prototype system is developed using a real-life modular construction project as a case study. It was found that the prototype system can improve the certainty and efficiency of the progress payment, thereby enabling smart payment in construction transactions. Without advocating radical changes (e.g., the contractual relationships or the intermediate role of banks in modern construction projects), the prototype can be developed into a real-life BBSC system that can work compatibly with current advancements in the field. Future works are recommended to fine-tune the findings and translate and implement them in real-life applications.     

Optimizing the performance of a repairable system under a maintenance and repair contract

In this article a number of maintenance models for finite horizons are reviewed. These methods have not been applied as frequently as their infinite horizon counterparts, and yet are very much applicable to systems under maintenance and repair contracts. The emphasis in this paper is on repairable systems under maintenance and repair contracts, where the decision has to be made whether and when to repair or replace the system. Based on a case study, a new finite horizon model will be constructed and new approaches to analyze and improve repair/replacement decisions under a finite horizon introduced. Finally, the meaning of ‘risk’ and ‘criticality’ in the context of maintenance contracts will be discussed and quantified. Copyright © 2007 John Wiley & Sons, Ltd.     

Transitioning defence aerospace support solution to service commercial sector maintenance repair and overhaul

Civil aviation as an industry has driven continued growth using third party MRO providers. This growing market attracted Defence organisations to explore the business opportunities of servicing in the commercial sector but they will face significant risks to overcome a large initial handicap before they can compete. This research compares the service requirements of MRO systems in defence sector and commercial sector to identify gaps between the two servicescapes. This paper contributes to defining the servicescapes between defence and commercial MRO service systems and enables the relevant service providers to be responsive to customer requests, but with scope to tailor the final design, and identify system efficiencies in the transition. A new support system is then designed for the defence organisations leverage off experience in the design and support of military aircraft to migrate to adjacent market.     

Estimating and ranking the impact of human error roots on power grid maintenance group based on a combination of mathematical expectation,Shannon entropy,and TOPSIS

Due to the importance of electrical grid reliability, analysis and evaluation of human error in the maintenance of electrical networks should be also considered seriously. The root causes of these errors must be identified and prioritized to plan for human error reduction. One of the objectives of the present study is to identify and predict these roots for power transmission maintenance groups from organizational, job position, communication, individual, and supervision aspects along with the relationships between these factors. In particular, this paper demonstrates that supervisor behavior as an external factor has a significant effect on maintenance personnel error. For this reason, special attention has been paid to identifying and controlling human factors from a supervisory point of view in this study. This paper also provides a method for detecting the extent of the expected influence of these roots on each personnel, since human error has a random nature. This is done based on the law of mathematical expectation. Finally, a method is suggested to rank roots based on greater effectiveness and evaluate personnel with higher error expectations. The proposed method is a combination of intermediate methods, Shannon entropy, and technique for order of preference by similarity to ideal solution (TOPSIS). The origins of the four human errors between 2014 and 2018 related to the two experts of Fars Electricity Maintenance Contractor Company are compared by the proposed method.     

基于模糊集表达和熵处理的产品用户需求评价

 在产品设计早期,对用户需求功能及其重要程度进行分析和获取的成功与否直接关系到产品设计目标特性的质量以及后续产品开发的各个阶段。提出一种基于模糊集表达和熵处理的有效用户需求获取方法。根据用户需求调查结果,建立了用户需求功能抽象的原则,采用模糊矩阵对各用户需求进行表达,并用熵处理的方法简化用户需求模糊矩阵,从而获取用户需求的重要度排序。该方法的显著优点是能够反应用户需求的主观性和模糊性。     

基于功能相关性的智能变电站二次系统功能测试验证方法

针对现有智能变电站二次系统功能测试结果仅通过观测二次设备行为得到,而未考虑设备行为背后的信息流程导致的被测功能正确性的误评估问题,该文利用分支流树建立能够反映功能与信息流关联关系的二次系统功能相关性模型,并以功能测试过程中的相关报文为触发条件,通过功能相关性模型与被测功能产生的信息对比进行被测功能正确性判断。通过自动布局算法完成测试过程中相关设备、链路、信息以及测试结果的展示。最后,通过在某220 kV智能变电站进行试验,证明该方法在测试环节中对功能正确性验证的有效性。     

六西格玛在广州市规划局IT运维服务质量管理中的应用

论文总结了目前广州市规划局IT运维服务工作中存在的一些问题,介绍了使用六西格玛管理方法测量IT运维服务流程、发现服务流程缺陷、改善服务质量,指出六西格玛管理方法与IT服务管理密切结合是提高用户满意度的有效方法。     

A data-driven maintenance policy for railway wheelset based on survival analysis and Markov decision process

Wheelsets absorb a significant part of the maintenance budget of any train operating company. Although wheel wear has been an extensively discussed topic in the literature, wear rates are very rarely characterized by using degradation data in a real-world case study aimed at identifying optimal maintenance policies including both degradation and recovery modeling. Furthermore, wheel defects, which impose an additional challenge to the modeling of the lifecycle of the wheels, are usually considered separately in the literature. In this study, conducted at a Portuguese train operating company, 17 years of inspection data are used to estimate wheel wear rates and survival curves, which are further incorporated into a Markov decision process (MDP) model. A bidimensional framework considering discrete intervals of wheel diameter along with a quantitative variable (kilometers since last turning/renewal) is used to represent the possible wheel states, while the probability of a defect interfering with the wheel maintenance schedule is modeled by contemplating survival curves derived from a Cox proportional-hazards model. Optimal results in terms of minimal cost policy are discussed in the context of the MDP, but a more realistic and easy-to-implement policy fixing one of the parameters is compared with the optimal policy. Results showed that in practice train operating companies might benefit from using the easy-to-implement policy, which has an associated long-run average cost only about 1% higher than the one suggested by the optimal decision map.     

A novel model for optimisation of logistics and manufacturing operation service composition in Cloud manufacturing system focusing on cloud-entropy

In recent years, economic globalisation and manufacturing resource globalisation as two key factors have driven enterprises to transform their business processes to survive in competitive environments. This transformation is challenging as manufacturing enterprises should maintain their support for their customers with high-quality products, lower cost, product customisation capabilities, and quick delivery. Moreover, globalisation has resulted in geographically distributed suppliers across the globe. This challenge will turn into a major research topic when paradigms like Cloud manufacturing are introduced. Cloud manufacturing is a new paradigm which provides ubiquitous, convenient, on-demand network access to a shared pool of configurable manufacturing resources. In this paper, to achieve the ideal goal of Cloud manufacturing, the concept of supplier network logistics planning and manufacturing service composition is focused. Every production task and logistics operation would be defined as a service considering operation process chart flows. The paper has proposed a mathematical model which selects an optimal set of manufacturing and logistics service composition in order to lower operation and logistics costs in operational perspective while fulfilling a novel idea for configured cloud entropy of logistics and operation suppliers. Finally, the paper has presented a numerical example and concluded the remarks, and outlined future research.     

楼宇三联供容量配置及运行方式的研究

楼宇冷、热、电三联供系统只有在合理的配置与运行方式下才能充分发挥节能、环保、综合效率高的优点。结合上海某工程案例,在能耗计算的基础上,对三联供系统不同的配置及运行方式进行比较。根据项目特点,提出＂三联供替代应急电源＂的容量配置模式。结果表明,按照上海目前的电价和天然气优惠价格,＂以应急电源大小确定燃气机组容量,且全年工作日满负荷运行＂方案是最经济性的。     

基于云计算关键技术的标准信息资源数据中心服务模式研究

本文采用了分而治之的思想,依靠众多的标准信息提供商,利用云计算技术,建设廉价、可靠,具备可管理性、可伸缩性的标准信息资源数据中心,为企业或公众提供按数据流量付费的服务模式.标准资源分散存储在各分站点上,但统一由总部管理和提供服务,所收取的服务费按照各分站点的资源访问和贡献情况进行分配,各分站点再根据版权协议把费用付给标准信息提供机构或个人.最后给出应用于专业镇标准信息服务的两个案例.     

An extended CREAM model based on analytic network process under the type-2 fuzzy environment for human reliability analysis in the high-speed train operation

Human error is one of the largest contributing factors to unsafe operation and accidents in high-speed train operation. As a well-known second-generation human reliability analysis (HRA) technique, the cognitive reliability and error analysis method (CREAM) has been introduced to address HRA problems in various fields. Nevertheless, current CREAM models are insufficient to deal with the HRA problem that need to consider the interdependencies between the Common Performance Conditions (CPCs) and determine the weights of these CPCs, simultaneously. Hence, the purpose of this paper is to develop a hybrid HRA model by integrating CREAM, the interval type-2 fuzzy sets, and analytic network process (ANP) to overcome this drawback. Firstly, the interval type-2 fuzzy sets are utilized to express the highly uncertain information of CPCs. Secondly, the ANP is incorporated into the CREAM to depict the interdependencies between the CPCs and determine their weights. Furthermore, human error probability (HEP) can be calculated based on the obtained weights. Finally, an illustrative example of the HRA problem in high-speed train operation is proposed to demonstrate the application and validity of the proposed HRA model. The results indicate that experts prefer to express their preferences by fuzzy sets rather than crisp values, and the interdependences between the CPCs can be better depicted in the proposed model.