Spatial Model for Path Planning of Multiple Mobile Construction Robots

Abstract:   This article presents a new spatial model for construction sites that supports path planning of construction robots. The model represents construction sites as partially known and partially unknown. Considering technological reality, spatial location accuracy constraints, and economical efficiency, only the essential boundary information is included in the known environment and modeled as a cell system and network. The cell system is a geometric object and provides the domain for path planning. The network is a topological object for computing the shortest path. Global and local planners are required for path planning to get the full benefits of the spatial model. The global planner computes the shortest path and provides it to the local planner as a sequence of vertices (subgoals). While following the subgoals, the local planner modifies the shortest path to avoid unknown obstacles.     

Use and Mis-Use of Measurement Scales in City Planning

By developing measurement scales the city planner can promote his long-run interest in integrating urban knowledge and his short-run interest in making valid analyses of specific problems. But the construction of measurement scales is not a random process and must be conducted according to logical rules. Inadequacies in current city planning scales are largely attributable to the lack of adherence to these rules. Housing quality scales, the most common measurement device in city planning, reveal some of the difficulties that lead to deficiencies in our measurement. The outlook is far from gloomy. Experience from other fields in index number construction, the use of scalograms, and factor analysis can Open up many promising avenues for city planning measurement.     

Three methods for verifying and validating the simulation of a construction operation

A simulation model must be verified to confirm that it describes correctly its intended real world process under study; moreover, the simulation results obtained must be a valid representation of the process. This study presents three activity-based white-box methods for assisting a user in verifying and validating construction simulations. The first method reports a simulation by listing all activities in the chronological order of their executions, so that a user can contrast the simulated progress against the actual progress in the real world. The second method summarizes the operating counts and mean durations of all activities over the simulated time period, to enable a user to evaluate whether all activities have been executed correctly during simulation. The third method generates an activity cycle report for any selected resource entity, so that a user can examine whether the entity is moving in the correct logical and chronological order during simulation. The three methods can be used jointly to debug a simulation model, so as to confirm that the simulation is correctly conducted and the obtained results are valid. The three methods are implemented in a simulation system in the form of corresponding reports. A concreting process is employed to illustrate these 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.     

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.     

成都乡村规划师制度的实践与展望

乡村规划管理是乡村建设与治理的龙头。成都市作为"全国统筹城乡综合配套改革试验区",在总结统筹城乡实践和"5·12"汶川地震灾后重建经验的基础上,于2010年探索建立了乡村规划师制度。作为深化城乡统筹的制度创新,它对成都乡村规划水平的持续提升、城乡融合发展起到积极作用,乡村地区的规划、建设和管理水平得到显著提升。新形势下,成都将继续完善乡村规划师制度。从定位与职责、管理与运行、实施成效等方面简要介绍成都市的乡村规划师制度,总结实践经验,并展望未来发展。     

An integrated modeling mechanism for optimizing the simulation model of the construction operation

A planner may use the discrete-event simulation to analyze and design the construction operation process that optimizes the overall performance of a construction system. Normally, the basic elements used in construction operation process simulation system, such as CYCLONE (CYCLic Operation NEtworks), are “activity” and “queue.” Activity is used to model the task which consumes resources and takes time to perform. Queue acts as a storage location for resources entering an idle state. In the simulation system, queues have to be created according to the ways of assigning resources to activities. Conventionally, planner defines queues according to his/her judgment by determining which and what amount of resources should be allocated to which activity. Consequently, various modeling schemes have to be examined to obtain the best simulation model. However, such a process of creating queues and activities is time consuming and requires iterations. This paper introduces a Genetic Algorithms (GA)-based modeling mechanism to automate the process of selecting the optimal modeling scheme. Case study shows that this new modeling mechanism along with the implemented computer program not only can ease the process of developing the optimal resource combination but also improve the system performance of the simulation model.     

European urban culture,Javier de Mesones-Cabello’s planning practice and its legacy in city of Valladolid

Javier de Mesones-Cabello was an influential and active planner of the 1960s and 1970s in Spain, who passed away in December, 2016. His professional career as a self-taught urban planner was extensively linked to his academic and institutional activities. These connections supported the establishment of relationships with prestigious professionals working in urban planning practice. In planning the 1969 masterplan for the city of Valladolid, in Spain, de Mesones-Cabello made several intellectual references to the Greek urban planner Doxiadis. This masterplan covers a relatively unknown example of directional city growth in a European context. My findings elucidate the extent to which de Mesones-Cabello was influenced by Doxiadis, and the circumstances in which these ideas have continued to dominate thinking about Valladolid's urban development.     

基于案例的推理和GIS相集成的技术在规划申请审批中的应用

基于案例的推理 (Case -BasedReasoning ,CBR)是基于知识的专家系统 (Knowledge -BasedSystems ,KBS)领域中的一个分支。它的基本思想是参照过去的案例 (case)来处理当前面临的新问题。这种系统能在自己的案例库中搜索以前解决过的类似案例 ,根据当时做过的决策及其后果对眼前的新问题提出合理的建议。与基于规则的推理和基于模型的推理等传统的专家系统技术相比 ,CBR直接利用具体、特殊、非抽象、众人认同的知识 ,因而适合于那些主观性强 ,不确定性强 ,牵扯因素多 ,特例多的领域。地理信息系统 (GIS)是处理空间信息的常用工具 ,它在城市规划中的作用已被普遍认同。本文介绍了作者集成CBR和GIS的尝试。这个集成系统旨在帮助规划师和决策者更好地处理和审批规划申请。该系统可为规划师迅速提供与当前申请性质相似或者在空间上相近的规划申请案例 ,以及在处理旧案例上的经验教训 ,帮助规划师提高工作效率 ,更全面地考虑问题 ,为最后的决策提供更可靠的建议     

Application of geographic information systems in construction safety planning

Execution schedule and 2D drawings are generally used for hazards identification in the construction safety planning process. Planner visualises 2D drawings into a 3D model and mentally links its components with the respective activities defined in the schedule to understand the execution sequence in safety planning. Sequence interpretation and accordingly the hazards identification vary with the level of experience, knowledge and individual perspective of the safety planner. Therefore, researchers suggest the use of four dimensional (4D) modelling or building information modelling (BIM) to create the simulation of construction process by linking execution schedule with the 3D model. Both however lack in the features like: generation and updating of schedule, 3D components editing, topography modelling and geospatial analysis within a single platform which is now a major requirement of the construction industry. This work facilitates 4D modelling, geospatial analysis and topography modelling in the development of safe execution sequence by using geographic information systems (GIS), both 3D model along with its surrounding topography and schedule were developed and linked together within the same environment. During safety review process if planned sequence results a hazard situation, it may be corrected within the GIS itself before actual implementation. Paper also discusses the use of GIS in the development of safety database from which safety information are retrieved and linked with the activities of the schedule or components of a building model. 4D modelling along with topographical conditions and safety database in a single environment assist safety planner in examining what safety measures are required when, where and why. Developed methodology was tested on a real life project in India, lessons learned from the implementation have been discussed in the potential benefits and limitations section. At last, paper highlights major research areas for further improvements.     

Financial Variables in Mental Housing

Urban activities surveys are workable bases for continuing planner-citizen dialogues. Seeking both to inform and to involve citizens, these exchanges also provide the planner with an avenue of collaboration with his client community. Findings from the surveys may be maintained in an activities base, which includes both quantitative and qualitative data on activities. Policy and planning decisions benefit from activities base data on the concerns and potentials of subcommunities. A pilot study of household activities demonstrates the usefulness and feasibility of the collaborative approach. This approach seems particularly appropriate in light of the wider definition of the planning realm now being recognized.     

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.     

The determinants of the vertical boundaries of the construction firm: comment

A method is presented for allocating resources to construction activities and for scheduling construction projects under resource constraints by considering the effects that such resource limitations may have on the tendency of the activities (and the project in general) to fall into disarray and behind schedule. Resource‐constrained scheduling problems (RCSP) are very common in real‐life construction projects and because of their nature their numerical solution is computationally intensive. The method utilizes a measure of each activity's perceived level of disorder stemming from resource limitations. The proposed technique aims to optimize the number of resources assigned to the activities and to schedule the project so as to minimize the overall project's tendency to fall into disorder. The entropy‐like metric used in the scheduling optimization is related to the ratio of required over‐assigned resource units per activity, and its utilization allows a planner to take into consideration project disorder when planning a project. A case study and its mathematical framework help demonstrate the ‘duration vs. disorder’ trade‐off analysis that planners should perform when considering possible activity resource assignments and the feasibility of these assignments in terms of induced disorder. The entropy optimization method proves to be a powerful project‐planning metric.     

Multi-agent-based simulation system for construction operations with congested flows

This study aims to develop a multi-agent-based simulation system to evaluate the traffic flow of construction equipment in construction site. It is known that traffic flow of construction equipment affects work efficiency and productivity. The conventional modeling approaches for discrete event simulation, however, have a limitation in simulating the flow of construction equipment because construction equipment has continuous dynamic behavior in the traffic flow. In order to describe behavioral characteristics of construction equipment by identifying changes in a dynamic environment, this study proposes the multi-agent-based simulation system and applies and tests it to simulate earthmoving operations. It is anticipated that the results of this study will help working-level construction engineers to assess the impact of traffic congestion during construction planning.     

团结奋进 勇于创新——探索具有中国特色的城市规划理论与实践

对随着我国的改革开放 ,城市所发挥的作用进行了阐述。分析了在此背景下 ,城市规划工作中存在的突出问题。提出理论和实践的创新是城市规划事业兴旺发达的基础和前提 ,并指出当前城市规划的工作重点是 :明确指导思想 ,全面推进小康社会的建设。     

城市骚乱背后的城市规划角度透视——以巴黎骚乱为例

20世纪以来大规模的社会骚乱已经是国际社会面临的越来越严重的问题,作者作为城市规划工作者意识到从规划角度分析骚乱的必要性和重要性。文章以巴黎骚乱为例,从城市规划角度分析引发其发生的城市社会环境,阐述法国的规划体系和规划方法对社会稳定与和谐的影响以及西方社会面对社会动荡采取的政策法规,文章最后总结了城市社会空间分异研究对中国城市建设的启示。     

The Social Relations of the Planner

The city planner, in playing his role, engages in a social process which can be analyzed in terms of a planning role, a client role, and a community decision network—all interacting around a public agenda. In the conceptual framework presented here, the planner is viewed as having a primary relationship with his client group, whom he must first motivate. Then, together, the planner-client team must relate to the larger community network, which they attempt to move. Both sets of relationships are affected by role postures, situational factors, and environmental conditions. This analysis suggests that traditional notions of the planner's role are too narrowly focused on substantive methodologies which imply highly simplistic assumptions about the social setting for planning.     

Generation of a construction planning from a 3D CAD model

In construction planning practice, increasingly 4D CAD system are applied for construction analysis and communication. Normally the planning expert is responsible for relating building components to construction activities. In this article we describe a method for automated generation of the construction planning. An algorithm is presented that derives the construction order from a solid model of the building. Experiences from a pilot study illustrate the differences between the real planning and the generated planning, and they show the limitations of the current implementation. Finally an outlook is presented on a more advanced planning system that includes contractor's specific knowledge for more accurate results.     

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.     

Augmented reality-based method for road maintenance operators in human–robot collaborative interventions

Road maintenance operators often work in dangerous environments and are in need of a support system to enhance their safety and efficiency. Augmented reality (AR) has proven to be useful in providing support to operators in various industrial sectors. However, the vast majority of the existing applications focus mainly on static, controlled environments, such as industrial shopfloors, although the dynamic flow of information that AR can provide could be very valuable to unstructured, dynamic environments. This paper presents a novel AR—based methodology for human–robot collaboration, real-time instructions, and support for road maintenance operations, aiming to enhance operator safety and efficiency. A robot operating system-based architecture is exploited for the communication of the modules. The methodology is tested in a laboratory environment, and the results validate the hypothesized enhancement of road operators. In the future, the application will be validated on real interventions in highways.