Computing in Civil Engineering (2002)

Based upon the graph-oriented knowledge representation two problems are considered: transforming functional requirements into layouts of houses and searching for optimum topology of trusses. It is shown that both problems can be conveniently formulated and then efficiently solved be means of specialized graph transformation rules.

Current solutions to agent development focus on using modal logic to program cognitive models of the problem solving process. Such solutions are often underpinned by the domain ontology and the programmatic solution involves equipping the agent(s) with the domain knowledge, which are expressed in terms of actions (primitive tasks), their pre-conditions, and their effects, and then directing the agent's behaviour in a way to achieve the desired goals using the underpinning ontology. However, there are difficulties with this approach to agent design and development especially to a domain expert/user who does not have the requisite knowledge engineering and/or programming experience. The problem is exacerbated if the domain expert receives little or no support from knowledge engineers. This paper discusses the problems in developing intelligent agents for use in the context of collaborative design. It reports a research study that investigated a solution that is based on the task reduction paradigm. The authors use the results of the experimental study to demonstrate that there will be greater synergy if the agent that is being developed complements human teaching efforts through automated reasoning mechanism. The paper also raises important professional issues that will drive the development of next generation ubiquitous systems in construction. Recommendations are given on how to improve the development of agent-based systems for collaborative working in the AEC sector.

The paper discusses a study on the application of intelligent agents (IAs) to conceptual designing. It provides an overview of the state-of-the-art in the areas of ontologies and IAs. Next, the system Disciple, a learning intelligent agent shell, and the system Inventor 2001, evolutionary design support tool, both developed at George Mason University, are briefly presented. Further, the paper introduces the developed ontology for a class of steel skeleton structures of tall buildings. This ontology was used to build an IA for the selection of initial parent design concepts in evolutionary designing. A description of the developed agent is provided as well. Finally, examples of design concepts proposed by the agent are presented. The paper also contains conclusions and recommendations for further research.

This research project aims at assisting both the architect and the structural engineer in the spatial configuration of the structural system as an integral part of the evolving 3D architecture. It allows the engineer to take full advantage of the opportunities provided by the architecture, at different levels of refinement, by directly deriving structural schemes from the 3D model. It also allows the architect to receive more opportune and informed structural feedback, and to detect structural problems earlier in the process. At the core of this approach lies a design representation that describes relevant information to both disciplines in a uniform framework and reflects the strong interdependency between the architecture and the structural system.

The research aims to develop a design process for multi storey steel framed structures that utilizes an integrated product and process model as its basis. It proposes that the quality of the current design process may be improved through better-informed design decisions that are based on the consideration of a wider range of design issues e.g. integration of building services with the structural system, choice of flooring systems etc. This can be achieved through the utilization of a single building product/data model that can be used by the different members of the construction supply chain. In such an integrated product model, it should be possible for the dependencies between several aspects of the design process to be made clearer e.g. effect of the building services on structural systems. This may aid in understanding the overall effects caused by decisions made in the early design stages on the overall building design process. The research also explores how an expert knowledge system that complements the proposed product model can facilitate the design process and help in decision-making.

The paper provides an overview of the manner in which evolutionary computation (EC) can be integrated with complex engineering design domains. Examples are drawn not only from civil and structural engineering but also from across the spectrum of engineering and industrial activity. It is hoped that this will provide a greater awareness of the breadth of potential and possible modes of application that are becoming apparent across all engineering sectors. In most cases fundamental aspects of the developed techniques and strategies are generic in terms of application and could therefore provide equivalent benefits across the diverse fields of civil engineering.

Optimizing highway alignments between given end points is a complex problem since there are numerous alternatives to connect two points in space. The initial efforts to design a highway were primarily manual and based on human judgment. Later, a number of search algorithms were developed to find an optimum alignment after formulating a number of alignment significant costs such as earthwork and pavement costs. Genetic Algorithms (GAs) were recently used to optimize highway alignments and were proven to be very effective due to their ability to avoid getting trapped in local optima while searching for a global optimum solution. A Geographic Information System (GIS) was integrated with GAs for practical application, which allowed working directly with real maps. The genetic approach however, had two main weaknesses: (1) a predetermined number of generations through which the search for an optimal solution was to be carried out, was necessary. It was a usual practice to continue searching through sufficiently large number of generations to ensure that global optimal solution was reached, which increased the computational burden considerably, (2) the integration with GIS while allowed working directly with real maps, further increased the computational burden due to the additional computation necessary in the GIS environment. In order to address the computational burden issue, here we introduce an alternative approach using Swarm Intelligence (SI) for highway alignment optimization. We perform a test example which indicates that swarm intelligence reduces the computational burden significantly.

Managing and reusing knowledge in architecture, engineering and construction (A/E/C) firms can lead to greater efficiency, productivity, and improved designs. However reuse often fails, since knowledge is not captured, it is captured out of context rendering it not reusable, or there are no formal mechanisms for finding and retrieving reusable knowledge. This paper presents ongoing research on design knowledge reuse that introduces the notion of knowledge in context. We argue that in order for knowledge to be reusable, the user needs to see the context in which this knowledge was created and interact with this rich content. We call a repository of such knowledge in context the corporate memory. We describe empirical observations of designers reusing knowledge from their personal design experiences. Based on these observations, we formalize two key activities that must be supported in the process of knowledge reuse from a corporate repository: finding reusable items, and understanding these items in context. We illustrate the use of a prototype system, called CoMem, that supports these activities with an industry case study. CoMem is distinguished from the document-centric state-of-practice solutions by its approach of "overview first, filter, and then details-on-demand" accomplished through the implementation of three interaction metaphors: corporate map, fisheye lens, and storyteller.

A methodology for supporting monetary risk assessment that combines probabilistic analysis with case-based reasoning is presented. Modern risk assessment requires the use of cost probabilities since for projects of reasonable complexity, deterministic methods for calculating costs are often misleading. Cost determination is complicated by the presence of dependent variables whose relationships with independent variables are project-specific. The probability distribution functions of independent variables and their relationships with dependent variables are constructed through an analysis of relevant past projects. These are used to compute the joint probability distribution functions using statistical techniques such as Monte-Carlo simulation and numerical integration. The methodology has been implemented in a software package called RACoPro and has been used in risk assessment of full-scale projects.

A major improvement to the current computerized estimating methods would be to incorporate a mechanism in the software system that allows determining an appropriate productivity for a work item based on the conditions of the project being estimated. One way to accomplish this is to use the productivity information from projects that a company has constructed in the past. Successful contractors have always kept records of completed projects, but this collection is usually in paper form. Files containing past project records are usually referred to as historical project databases. A well-prepared historical project database contains observed crew productivities and a description of project conditions affecting productivity. If estimating software were given access to a digital library of historical cases, it would be possible to query the library for an appropriate productivity for the conditions of the project being estimated. This study presents an estimating approach that relies on historical cases for predicting appropriate productivities for a new estimate. The scope of the study is limited to masonry block wall construction. Masonry wall cases are modeled using object-oriented technology. A commercial object database management system is used for storing historical cases.

Many construction conflicts can arise from the separation of design and construction in the current AEC industry. Constructability analysis has been proposed as an effective method to fill the gap between the AEC project design and construction. However, the project information model can be improved to integrate product information and process information and to provide a framework for incorporating construction experience and knowledge. The product oriented scheduling technique (POST) is presented to provide an alternative scheduling technique with the aim to integrate the static product system and the dynamic construction progress configuration in a uniform description context. Another aim of POST is to provide a knowledge management tool for construction sequence knowledge. This paper introduces the concepts and the network structure of the POST model. It also explores the incorporation of construction sequence knowledge into the component state network. It is suggested that the POST model can reduce errors arising from mapping product models and process models, and improve constructability analysis.

A strategic goal of the Nuclear Engineering Institute as defined in Vision 2020 includes the addition of 50,000 MW of safe and reliable nuclear plant capability in the United States by 2020. To meet this goal, the new plants will need to be developed in an efficient and safe manner. New visualization technologies including 4D CAD and immersive display environments offer promising avenues to improve design, construction, and operation processes of these complex facilities. This paper presents our progress to evaluate the application of 4D CAD and immersive display tools to reduce the time to and costs of constructing new nuclear plants. The results from the initial phase of this research show that the use of a virtual immersion environment to display the 3D plant design is beneficial to the designer and contractor. Our current focus is on the development of tools to allow construction experts to better visualize the construction sequence using 4D CAD so they can provide critical design feedback prior to starting construction. This will ultimately reduce the number of construction interferences in the field and help minimize the quantity of changes during construction.

The Pentagon Renovation Project - Wedge II to V is a highly repetitive project which provides many opportunities for cost and schedule savings through detailed construction planning. This paper presents a case study example where graphical construction simulation was used to analyze and communicate the flow of mechanical work on the renovation project to maximize production for repeatable work units. To date, most applications in graphical construction simulation or 4D CAD have focused on the development of a construction sequence for a large, complex structure. This case study provides an illustrative application of the use of graphical construction simulation for developing a detailed production plan for repeatable work sequences. The CAD simulation model shows the work flow, work space requirements, and material handling for one typical repeatable area. The model was presented to trade superintendents and foremen and valuable feedback was obtained.

This research is to solve the integration problem that is caused by the fragmentation of the construction industry. A solution that combines the benefits of process model and product model is proposed. An advanced transaction model with ACTA properties is used in the system instead of the traditional. A prototype is built with Java and CORBA technology to compare the advanced transaction model against the traditional model. Shared information objects are maintained at the sites representing 5 types of participants in a construction project. Transactions are issued against shared information objects according to the roles and operations of the sites. Tests show that both the performance and availability of resource are improved because of the use of an advanced transaction model. However the benefits diminished with the increase of rollbacks of transactions. The scalability of the systems is closely related to the functionality of the shared information object.

Described is a visualization environment for construction schedules that supports linear planning charts, bar charts and network diagrams, and the ability to switch from one representation to another effortlessly. Advantages of the approach include the ability to gain a "big picture" view of the overall construction strategy including its design and optimization, the ability to drill down into local details of the schedule, and the ability to identify the most effective corrective action strategy.

Discussed in this paper is how current knowledge-based approaches for risk management of large infrastructure projects can be improved upon so that they are more responsive to the attributes of a project and the needs of system users. A review of existing knowledge-based systems for risk management provides a backdrop for the discussion. The proposed methodology adopts a model-based technique in that explicit abstractions of project components and processes, and the physical, regulatory, political, social, financial, economic, contractual and organizational environment in which they are located, are created to assist in the reasoning about possible risks. This contrasts with several current systems that use only implicit representations. The reasoning schema, as well as models of the project and the environment that are used for the reasoning process are described in the paper.

The widespread use of information technologies for construction is considerably increasing the number of electronic documents stored in inter-organizational construction management information systems. Since a large percentage of these project documents is generated in text format, methods for organizing and improving the access to the information contained in these types of documents becomes essential to construction information management. Document management techniques have been used for this purpose. One limitation of the document management aspects in current information systems is the reliance on manual classification methods. With the widespread use of information technologies for construction, the increasing availability of electronic documents, and the development of systems based on project object models, manual classification and organization becomes unfeasible. This paper describes a methodology to improve information organization and access in inter-organizational systems based on automated classification of construction project documents according to their related project components.

This paper presents the findings from the use of Industry Foundation Classes for the design and construction of the Helsinki University of Technology Auditorium Hall (HUT-600) in Finland. For HUT-600, IFC implementation supported the sharing of geometric data, thermal values, and material properties among the architects, mechanical engineers, and general contractors. The implementation benefited the project with minimized data re-entry, increased accuracy of information exchange, and reduced design time during the early project phase. However, the immaturity of IFC-compliant software and middleware undermined the reliability and a more rigorous testing of the IFC's. Analyzing the HUT-600 case study, we suggest that researchers and software developers focus on partial data exchange, model server approach, and software robustness to extend the benefits and improve the reliability of the IFC's.

This paper looks at the development of Change Process Models that can be used to manage the complex interaction of versioning, change notification and the resulting constraint and conflict resolution that may be required. The work is put in the context of providing software to assist a design team in such a way that they can tailor the system to suit their own needs. The Change Process Models are described using UML activity diagrams and the work has been implemented by using a novel form of workflow software linked to a versioning system.

This paper will describe current materials management practices for the electrical contractor. The review is mainly based on interview visits to electrical contractors, suppliers/distributors, and software providers. Based on these site visits, the typical material management process for purchasing, delivery and handling will be presented. The paper will specifically address material management processes associated with purchasing strategies and scenarios, alternative delivery options to the construction site or to a warehouse for prefabrication and/or storage, and on-site material handling and distribution. Based on the information collected from the interviews, problems and bottlenecks in current material management practices are identified and summarized.

Without a comprehensive understanding, a construction production process model can be flawed and a resulting production process design may be sub-optimized. Proper understanding of the entire production system is the first step in the design of an effective construction production process. This paper aims to provide a conceptual framework to enable understanding of construction production behaviors and to facilitate the design of construction production processes. This framework is based on observations of construction production characteristics, fundamental concepts of system theory, and ideas from many fields including manufacturing production, business process design, and lean construction. Production system analysis is accomplished by using discrete-event simulation for modeling and meta-heuristic methods for optimization.

A fundamental strategy for reducing project delivery times is overlapping sequential activities. The degree to which activities (whether design or construction) may be overlapped is defined by the nature of the information exchange between those activities. Concurrent engineering literature describes this information exchange between an upstream task and a downstream task in terms of the natural rate of information development in each task and the sensitivity of the downstream task to changes in upstream information. These concurrent engineering concepts can be extended from the static manufacturing environment and adapted with the use of information technology for use on the dynamic interface between design and construction. The first step in this process is to formalize the methodology for applying concurrent engineering principles to the AEC industry. This paper presents a proposed methodology for formalizing this process. The methodology proposed in this paper is the first step in an ongoing study to create a process for overlapping design and construction activities with the goal of reducing overall project delivery times. Future work in this study will apply this proposed methodology in a series of case studies, with the goal of identifying overlapping rules and the associated costs or risks of applying those rules to a project. Once a formalized process has been created, information technology tools can be developed to allow the AEC industry to utilize this process and thus, achieve shorter project schedules.

This paper describes a mediation based software framework for the development of a ubiquitous computing environment for distributed engineering services. Two fundamental issues are addressed: (1) universal accessibility from devices to services, and (2) coordination and interaction among the parties accessing the services. A prototype infrastructure has been developed and illustrated using a variety of project management application software as well as different devices ranging from PDA, web browsers and desktop computing.

The increasing demand on manufactured houses has urged production managers to (i) improve the productivity of the manufactured housing construction processes by reducing the cycle time and (ii) to enhance the quality of both material and level of technicality used. A simulation model for the manufactured housing factory was developed in Arena to study the production process. This software is designed for modeling production processes and other systems in support of high-level analysis. Arena offers advanced capabilities to mimic the behavior of the real system components, layout and flow logic, and to produce data distributions and confidence intervals for the performance measures, as well as display animation. This paper will discuss the production process in a manufactured housing factory and illustrate the simulation model that was developed to analyze the system efficiency and to determine the bottlenecks in the production system.

The construction industry had been known for its poor safety performance. Poor safety performance is unacceptable both ethically and economically. In order to improve safety performance, it is widely accepted that the industry needs to implement efficient and effective safety planning prior to commencement of site activities. This paper presents the Safety Knowledge Management System (SKMS), which is meant to assist safety-planning teams in developing and improving safety plans for construction activities through the reuse of past safety knowledge. The SKMS is based on Case Based Reasoning (CBR) methodology and technology, which is a relatively new area of artificial intelligence. CBR is chosen mainly due to the ease of maintenance of CBR systems and the episodic nature of the safety knowledge employed in the system (safety plans and incidents). This paper describes how CBR is being applied to facilitate the development of risk assessment tree based on past cases. A hypothetical safety-planning scenario is also presented to explain the CBR concepts proposed.

The Virtual Coach is a web-centric virtual environment that creates temporally dynamic clinical exercises known as situational simulations, with the intention of exposing participants to rapidly unfolding events and the pressure of decision-making. This paper deals with the databases, which store all the data relevant to situational simulations executed by the Virtual Coach. It defines the nature of the data and describes the relational databases used. The Virtual Coach uses two types of databases, the ‘as-planned' and the ‘as-built.' While the ‘as-planned' database stores information about how a particular project can be completed when executed on schedule and within budget, the ‘as-built' database, dynamically records data regarding the actual execution of the project, by a particular participant. This paper discusses the design and the modes of functioning of these databases.

In the construction industry, the collaboration between several professional participants (who usually come from diverse organisations); and the integration of the numerous computer applications (which are normally introduced throughout a project's lifecycle, to solve specific problems and support individual information management), are the cornerstones for successful delivery of a planned project. Traditional approaches to collaboration have proved inefficient. For this reason, the need for time and cost-effective computer-based collaboration between participants in the construction industry has become a major issue for researchers and standardisation bodies. There have been several efforts towards improving collaboration in the AEC sector, from a product-data point of view. However, the process centred-views of construction information have not received much attention. In the manufacturing sector an ontology-based mechanism: the Process Specification Language (PSL) has created a neutral, standard language for process specification to serve as an interlingua to integrate multiple process related application. This paper introduces research work, aimed at developing an ontology-based framework, based on the PSL language, for interoperability of process-related applications in AEC sector. This involves investigation of the applicability of the Process Specification Language (PSL) concepts to the representation of construction process information.

This paper reports on an on-going research project concerned with developing an alternative approach to simulating the thermal behavior of residential buildings, based on artificial neural networks (ANNs). The primary objective is to capitalize on the modeling versatility of neural networks to facilitate coarse-grain modeling of complicated composite structures, and to allow design variables to be treated as simple inputs to the model. This approach, in contrast to more conventional modeling approaches (such as the finite element or finite difference methods), enables models to be built quickly, reduces the processing time of a simulation, and allows alternative designs to be evaluated without having to rebuild the model. Such a tool will enable a large number of alternative design decisions to be evaluated within a short period of time, thus allowing an architectural design to be fine-tuned to minimize life cycle costs.

The successful initiation and execution of a virtual team is gaining increasing attention in the design and construction community. From opportunities to integrate international teams to the opportunity to leverage the best resources in an organization on a given project, virtual teams can transform the concept of project execution. However, potential barriers exist in several areas to the successful implementation of virtual teams. The need for increased management emphasis, social and cultural understanding, and emphasis on common goals are only a few of the non-technical factors that can turn successful virtual teaming into virtual frustrations. When combined with traditional technical challenges including compatibility of systems, security, and the selection of appropriate technologies, the line between leveraging virtual technologies for enhanced solutions and introducing complications into the project process is a thin one.

The current demand on engineering firms to complete design documents in a short time frame is increasing in order to maintain profitability and satisfy client demands. An engineering firm specializing in the design of segmental retaining walls implemented the use of an interactive web site to disseminate bid packages to contractors and material suppliers in different locations across the United States. Through the use of computer aided design software, spreadsheets, and digital photography, all of the necessary information required to prepare a competitive bid by a contractor or a material supplier can be posted to a password protected web site by the design engineer. Transferring design build bid packages through the internet has proven invaluable to the engineer. Completion time for the individual designs has been greatly decreased and therefore overall productivity of the engineer is augmented by using electronic methods of transferring information. However, despite the advantages of web based segmental retaining wall design build packages to both the engineer and contractor, the industry has not achieved a reliance on web based information. A tutorial on basic computer skills, electronic information and interactive web sites is proposed to increase the knowledge of the clientele in the use of the World Wide Web and interactive web sites. The tutorial includes synchronous instruction on basic computer skills and web navigation for inexperienced users, and asynchronous web based tutorial using learning objects for experienced users. The proposed tutorial provides a means for contractors to effectively use the interactive web site to obtain segmental retaining wall bid packages.

The ever changing IT landscape presents both opportunities and problems for design teams in the engineering and construction industries. A recent Black & Veatch project illustrates the benefits and challenges of using a wide variety of IT tools for project design and construction. The project involved design of a large membrane water filtration facility on the site of an existing traditional water treatment plant.

Global positioning systems are now widely used for navigation purposes and the International Space Station is under construction, marking the advent of the space and information age. Additional infrastructure such as the Stratospheric Platforms (SP); "Sky-Infra" will also be built within the next few decades. What are stratospheric platforms? Whereas Earth observation, communication and broadcasting satellites except geo-stationary satellites orbit the earth at very high speed, stratospheric platforms are only about 20 km above the earth's surface, or several tenths of the height of ordinary Earth observation satellites. A stratospheric platform can use high-frequency radio waves for many channels, enabling dense information communication between the SP and the ground radio-stations at about several tens of Mbps, and can mount high-resolution optical sensors. This paper summarizes the situation, characteristics, and potential applications of information-rich stratospheric platforms as civil engineering infrastructure for the advanced information society of the future.

Structural engineering computer programs are used extensively in the industry in order to analyze and design structures. Several classical methods of analysis that are still presented in textbooks on Structural Analysis have not been used in the industry for many years. Code checks are done using the computer and reports generated automatically now complement the engineer's hand calculations. In order to reflect the current engineering practices, the teaching of structural engineering should include computer programs. Basic concepts specific to computer modeling of structures include the definitions of nodes and members, degrees of freedom, connections, types of analysis, etc. State-of-the-art computer programs have wide applications and can be presented in several structural engineering courses such as Structural Analysis, Steel Design, Concrete Design, etc. By freeing students from sometimes tedious hand calculations, attention can be better focused on the behavior of structures. The present paper will briefly review the evolution of structural engineering computer programs and will present examples that show how a state-of-the-art computer program can be used effectively in teaching several courses in structural engineering.

This paper describes a method used to construct a thesaurus in the field of civil engineering. This work is an effort to investigate the potential of thesauri as a tool for information retrieval systems and as an aid in civil engineering. ThesWB, a tool that extracts terms and relations between them from HTML documents, was used for collecting candidate thesaurus terms from Web. The principal advantage of the Web as a source for thesaurus construction is that it can be viewed as a body of text containing two fundamentally different types of data: the contents and the tags. A tag in HTML is meta-data describing the layout and linking structure between the texts. For these kinds of documents we can apply different approaches to extract and structure terms automatically. ThesWB is used to construct domain independent thesaurus from HTML pages.