大都市社区公共服务设施供给研究——基于“三三制”的体系构建

大都市区中心和外围空间一体化演化过程中,社区空间和人口结构急剧变化,社区公共服务设施供给面临挑战。本文从设施供给全过程,构建了以“建控用”为核心,“三阶段贯通,三条线协同”的“三三制”大都市区社区服务设施供给体系,强调“全覆盖供给、全环节管控、全周期运营”框架。结合常州新北区进行实证校验,探讨都市区社区服务设施供给体系的转型。供给环节应结合居民需求,明确分类设施供给标准、供给主体和空间模式,保障设施供给的公平性;管控环节要优化专项规划和控规规划编制,加强实旅过程的环节控制,保障空间供给的有效性;运营环节推进社区规划和社区规划师制度建设,建构监管与沟通并重的运营管理机制,提高社区设施供需匹配效率。     

Virtual experiment of innovative construction operations

The planning of construction operations is a complicated activity involving abstraction of construction activities from the drawings, choosing of suitable plants and falseworks, allocation of resources on site, planning of safe working place for labourers, and the scheduling of activities sequence. The increasing competition among contractors demands them to adopt innovative construction methods, which have not been used or tested previously. It is not until the beginning of actual construction that the construction planner can realize the validity of his construction operations planning. The lack of tools for the construction planner to evaluate and validate his planning can result in incorrect construction plans, which cause a lot of rework in the construction phase. Virtual Reality (VR) technology, on the other hand, is very likely to provide a solution to the above problem. VR system generates virtual environment containing objects with real world properties and allows user/planner to interact with the objects. This paper proposes an integrated VR system that generates near to reality construction environment for the construction planner to perform construction activities in a real world manner in order to plan, evaluate and validate the construction operations.     

Construction management process reengineering performance measurements

This study develops a construction management process reengineering performance measurement (CMPRPM) model based on an application of business process reengineering philosophy. Process operation time and customer satisfaction are used as efficiency and effectiveness evaluation indices. The CMPRPM model applies queuing theory to calculate process operation time in order to strike an optimal balance between process execution demand and manpower service capacity. In order to achieve customer satisfaction, customer demands are identified and a target attainability index is used to calculate process effectiveness. After integrating efficiency and effectiveness evaluation results, indices of process value (PV) and value improvement (VI) are proposed to allow performance prior to and after reengineering to be measured and compared. The proposed CMPRPM model addresses the performance of initial (“As-Is”) and significantly reengineered (“To-Be”) processes to facilitate successful BPR design. Results show that the construction industry stands to benefit significantly in terms of a successful BPR design by adopting the model proposed in this paper.     

Planning linear construction projects: automated method for the generation of earthwork activities

Earthworks planning for road construction projects is a complex operation and the planning rules used are usually intuitive and not well defined. An approach to automate the earthworks planning process is described and the basic techniques that are used are outlined. A computer-based system has been developed, initially to help planners use existing techniques more efficiently. With their input, the system has been extended to incorporate a knowledge base and a simulation of the earthworks processes. As well as creating activity sets in a much shorter time, the system has shown that for a real project, the model is able to generate activity sets that are comparable to those generated by a project planner.     

Queue performance measures in construction simulation models containing subjective uncertainty

In recent decades, discrete event simulation (DES) has been widely used for analyzing construction projects. Recently, fuzzy discrete event simulation (FDES), which is an integration of fuzzy set theory with DES, has been proposed for simulating construction projects. FDES provides a framework to consider subjective uncertainty (uncertainty due to vagueness, subjectivity, and linguistic expression of knowledge) in construction simulation models. Current FDES frameworks only calculate simulation time (e.g., project completion time) as the simulation output. However, queue performance measures (e.g., average queue length and waiting time)—though important simulation model outputs for decision making, finding bottlenecks, and optimizing construction resources—are not analyzed in current FDES methodologies. Using fuzzy logic to consider the subjective uncertainty of service time and the inter-arrival time of systems' queues may improve such simulation models by more realistically representing their results. This paper provides a novel methodology to consider subjective uncertainty in analyzing the fuzzy queues in construction FDES models. Incorporating fuzzy queuing theory with FDES methodology as proposed in this paper enhances the applicability of FDES in construction projects. The proposed methodology is validated through mathematically solved queueing examples, and its practical aspects are illustrated using an example of an asphalt paving operation.     

Innovative supply-based strategies in the construction industry

The quantity of some resources is limited because of project cost constraints. These resources may be required by multiple activities simultaneously during a construction process. In a discrete simulation that models the construction process, tracing and controlling such entities, e.g. resources, is crucial to simulation. This paper presents a resource allocation point (RAP) heuristic that takes into account the dynamic and stochastic charateristics of simulation to enable the activity-based construction simulation system to process a decision-making ability, i.e. allocating the limited resources to the multiple computing activites during simulation. In addition, this paper introduces an activity object-orientated approach that implements the RAP heuristic and speeds up the simulation experimentation through initiating and checking only related activity objects instead of scanning all activities as in a pure activity scanning (AS) simulation strategy.     

Examination of the effects of a KanBIM production control system on subcontractors' task selections in interior works

Work flow and productivity in construction project production systems can be improved through thoughtful planning with systematic avoidance of waste coupled with the use of appropriate production control systems. Collection and distribution of accurate, reliable and timeous information describing the states of the processes and products are essential. This study examined the effect of an information system based on building information modeling (BIM) on the decisions made by construction trade crews when determining their sequence of work. A prototype system, called “KanBIM”, was used by subjects working in a virtual construction site experimental setup using a virtual reality CAVE linked to a discrete event simulation engine, to guide their performance of “virtual” work in a building with sixteen apartments. The use of the system improved the process flow and eliminated waste. It gave the subjects situational awareness, leading them to perform the right work, reducing rework and time wasted.     

Rapid,on-site spatial information acquisition and its use for infrastructure operation and maintenance

Site modeling can be useful in various safety-enhancement applications and for as-built data acquisition. In this article, a rapid, on-site, spatial-modeling method using a “sparse point cloud” approach that represents construction sites in an efficient manner is proposed. The various procedures used in the modeling process are explained. The results of the experiments performed on actual construction sites are described, as are case studies of the modeling method per se. An example of the application of the proposed site modeling method to the simulation of obstacle-avoidance in the operation of equipment on an industrial construction project is also presented.     

Optimizing schedule for improving the traffic impact of work zone on roads

Many different types of construction projects set up work zones on roads. Especially in urban areas, lane closures as a result of work zones have a considerable impact on local traffic. However, for a construction project that consists of several work zones and several work crews, the traffic impact may be improved by appropriate scheduling. Therefore, this paper proposed a scheduling model based on the route-changing behavior of road users. The proposed model calculates the traffic delay of vehicles by microscopic simulation, and applies team ant colony optimization to search for a near-optimal schedule. The project planner then ensures that the contractor executes the activities according to the near-optimal schedule. The proposed model is applied to schedule a sewer system construction project in a city. The results of our study indicate that with our proposed model the total traffic delay is reduced by 11.1% when compared with a schedule proposed by the project planner.     

Action-based union of the temporal opposites and elastic activity network in scheduling

It is the time resource that one deals with in scheduling. The task is how one can achieve the optimal allocation of a given time resource over a set of assigned activities. Most of the existing scheduling methods use a parametric time by which the activities are orderly allocated in accordance with the order of events. The parametric methods however fail in incorporating a dynamic aspect of scheduling that unfolds itself as the project proceeds as well as inerasable uncertainty in activities whose starting and ending nodes fluctuate. This paper reformulates the concept of time to match to a dynamic scheduling through a non-deterministic modeling of scheduling as a “mapped/represented” and “transformed/processed” temporal movement. It will be shown that an elastic interpretation of activity fluctuation can be derived naturally from the model, which allows us to develop an elastic network method for scheduling.     

基于设计结构矩阵的最后计划者体系流程运行评估

最后计划者体系（Last Planner System,LPS）是一种实现精益建造的有力工具,其功能的实现依赖于流程中各活动和交互关系的良好表现,但计算计划完成百分率（the Percent Plan Complete,PPC）的方式不能满足项目管理者对整体流程的掌握。引入一种结构化建模工具——设计结构矩阵（Design Structure Matrix,DSM）帮助管理者表示、理解、管理 LPS流程。基于文件、访谈、实地调查获得的数据,结合两种 DSM 展示了 LPS 流程中活动和交互的情况并选择应用 LPS 的工程建设实例验证 DSM 对 LPS 流程运行评估的有效性。单双值 DSM 共同展示了 LPS 流程中活动和交互情况,双值 DSM 进一步求解出交互活动链,流程评估研究将为 LPS 的高效运行和精益建造管理工作提供依据     

Task planner design for an automated excavation system

An automated excavation system, which is a robotic excavator with site modeling capability, is being developed by a Korean research consortium in order to improve the productivity, quality, and safety of conventional earthwork. This paper presents the excavation task planner devised to incorporate the intelligence of a construction planner and a skillful operator into the robotic control mechanism of the automated excavation system. The excavation task planner aims to generate an optimal excavation plan based on 3D models of the work environment and the excavator updated by various cognitive technologies. The structure of the task planner was designed in harmony with the sensing and the control schemes of the automated excavation system. The algorithms used to partition the work area and to generate the excavator path were developed as the critical components of the task planner. The suggested design of the excavation task planner focused on the functions required to utilize the automated excavator at actual construction sites. Case studies showed that the task planner was able to generate effective work plans that could be fed into the automated excavation system.     

The “penalty factors” method for the prediction of TBM performances in changing grounds

Tunnel construction by TBMs through hard rock is significantly affected by the geological and geotechnical conditions at tunnel level. Ground parameters such as uniaxial compressive strength, fracturing degree and abrasiveness, and factors such as water inflows and stress level may deeply affect the way a TBM will perform. In addition, different types of TBMs will behave differently in a given condition.This paper presents a method for TBM performance prediction in changing grounds, which has been developed in the framework of the European project “New Technologies for Tunnelling and Underground Works” (NeTTUN). The model starts from an optimum TBM performance in best conditions, i.e. when all ground parameters are in their “best state”. A stepwise reduction of the optimum advance rate is then performed, according to “reduction factors” that quantify the effect of degrading ground conditions on the TBM advance rate. By doing so, the “penalty factors” model is able to take into account a very wide range of ground conditions, from very good to very poor. Two types of TBMs commonly employed in rock tunnelling have been considered, i.e. Gripper and Shielded machines, each of them characterized by its own set of reduction factors.In order to consolidate the factor values and to validate the model, a TBM performance database, also developed in the framework of the project NeTTUN, has been used. The database includes a large number of tunnels excavated in different ground conditions with all standard TBM types. The comparison between the values given by the “penalty factors” model and the actual TBM performances observed during construction shows that the developed tool may provide a reliable estimation of the TBM performance based on simple ground parameters.The “penalty factors” model has also been interfaced with the DAT (“Decision Aids for Tunnelling”). The DAT software, co-developed by MIT and LMR-EPFL, is able to compute the probabilistic distributions of the tunnel construction time and – cost in function of the geology – and construction related uncertainties.The model is conceived to be used in its present form. However, the methodology can be easily adapted to match the expertize of the user, who is free to update the optimal performances, the ground parameters and/or the values of the reduction factors according to his/her own experience. The model can also be extended to other TBM types and to conventional excavation methods.     

Classical Planning Model‐Based Approach to Automating Construction Planning on Earthwork Projects

Extensive research in automated operation planning has led to significant advances in the area of robotics. Theories and methods resulting from robotics have yet to be adapted to enable automated project planning in construction engineering. Aiming to demonstrate the potential of implementing automated planning theory and methods in construction project planning, we developed an automated earthwork planner prototype following the principles and framework of classical planning model in computer science. As time is not explicitly represented, implementing classical planning model to perform optimization and planning simultaneously results in potential temporal–spatial conflicts (TSCs). The present research develops a two‐step approach to separate operations optimization and earthwork planning in typical rough grading projects. As such, TSCs encountered in existing mathematical programming based earthwork planning methods are resolved. To enable fully integrated and automated earthwork planning, the prototype system has been seamlessly integrated with project scheduling and operations simulation software for higher level analyses. To demonstrate advantages of the automated planning methodology, construction plans were independently produced by 14 graduate student teams on the same “testbed” project; results were evaluated and compared with the plan generated by the proposed system.     

Integrating BIM and GIS to improve the visual monitoring of construction supply chain management

In recent years, with the increasing level of competition in the global construction market, several research efforts have focused on the application of information technology (IT) as a way to improve the integration process of construction supply chain management (CSCM). Visual representation of the process can provide an effective tool for monitoring resources in the CSCM. In order to support this objective, this paper integrates building information modeling (BIM) and geographic information systems (GIS) into a unique system, which enables keeping track of the supply chain status and provides warning signals to ensure the delivery of materials. First, the proposed methodology is implemented by using BIM due to its capability to accurately provide a detailed takeoff in an early phase of the procurement process. Furthermore, in order to support the wide range of spatial analysis used in the logistics perspective (warehousing and transportation) of the CSCM, GIS is used in the present model. Thus, this paper represents the integrated GIS-BIM model manifesting the flow of materials, availability of resources, and “map” of the respective supply chains visually. A case example is presented to demonstrate the applicability of the developed system.     

Urban Sociology as an Aid to Urban Physical Development: Some Research Strategies

This article compares two planning orientations and their impact on the development of an urban renewal plan for Boston's South End from 1961 to 1965. Research showed that the first planner implicitly adopted a “power elite model” of planning while the second planner adopted a “pluralistic model.” This study found that use of these two orientations, or models, had a major influence on four aspects of planning: (1) planning process; (2) planner's use of influence; (3) citizen groups with whom the planner primarily worked; and (4) planner's relationship with central office. It was also concluded that the nature of the produced plan differed as a consequence of the planning style used.     

“碳中和-新乡村”视角下广东乡村分布式光伏构建模式探索

我国作为碳排放大国,要实现碳达峰、碳中和的目标,乡村的低碳化发展将起到关键作用。随着乡村振兴战略的推进,乡村发展高碳排放加剧,同时亦展现了生态系统碳汇资源与新能源发展的空间资源优势。碳中和与乡村振兴两大国家战略具有紧密的内在关联,应构建“碳中和-新乡村”战略耦合机制,推动城市资本、人才、技术与乡村的丰富的生态碳汇资源、广袤的空间资源的良性互动,开辟城乡资本、资源流动的新途径。基于新的视角,依托广东省太阳能资源丰富,存量农房数量巨大的资源特性,探索了建设“乡村分布式光伏”的技术体系、实施路径及运营模式。最后从乡村新能源发展延展到对乡村绿色发展新模式——“碳中和新乡村”的思考。     

浅埋单护盾TBM隧道施工地表变形规律研究

重庆轨道交通环线重庆西站-上桥站区间使用单护盾TBM进行施工,通过浅埋段时,因隧道拱顶穿越的基岩最小厚度已不足0.5 m,极可能会给工程带来极大安全隐患。按设计要求,对上覆土体进行旋喷桩加固与钻孔注浆加固。利用有限元数值软件ADINA建立该区段的精细有限元模型,并提出了适用单护盾TBM施工特点的数值模拟方法。数值计算结果不仅说明了表层土的加固是有效的且十分必要,并对单护盾TBM掘进过程的三个主要施工参数研究与对比分析,总结出工程浅埋段"最优掘进参数"。对比现场地表位移监测数据,总结得出该浅埋区间单护盾TBM隧道施工地表横向变形曲线"高低肩"的特点;另一方面也验证了数值模型的可用性与模拟方法的正确性,可为该区域其它地铁线路的施工提供借鉴与参考。     

服务土木工程三层次课程体系的虚拟仿真实验教学资源建设

为了培养学生的专业兴趣,以及应用创新能力和解决复杂工程问题实践能力,提出服务于土木工程三层次专业课程体系,即土木工程“核心—方向—拓展”课程体系的虚拟仿真实验教学资源的建设与应用思路。三层次课程体系具有将实验教学与理论教学、实践教学与工程实际有机结合的特点。新开设具有“虚实结合”特点的土木工程综合实验(含虚拟仿真)课程,包含土木工程专业急需的实验教学内容,以适应大学生成长的新特点和信息化时代教育教学的新规律。依托国家级实验教学示范中心、国家级虚拟仿真实验教学项目和多项教研教改课题,以虚拟仿真“金课”标准建成服务于三层次课程体系的虚拟仿真实验资源库,并结合虚拟仿真项目、课程建设及教材建设,构建立体化教学资源。     

Evaluation of queuing systems for knowledge-based simulation of construction processes

During the course of a construction project, there are many situations in which formation of waiting lines or queues is inevitable. The effect of resource delays in queues on the overall project completion time and cost has motivated researchers to employ simulation for analysis of queuing systems in order to identify the best operational strategies to reduce the time wasted in queues. Providing proper and timely input data with high spatial and temporal accuracy for queuing systems simulation enhances the reliability of decisions made based upon the simulation output. Hence, the presented paper describes a methodology for collecting and mining of spatio-temporal data corresponding to the interactions of queue entities to extract computer interpretable knowledge for simulation input modeling. The developed framework was validated using empirical datasets collected from a series of experiments. The extracted relevant knowledge from the queuing system entities was used to update corresponding simulation models.