Showing papers in "Journal of Computing in Civil Engineering in 2003"
TL;DR: This paper provides a comparison of the effectiveness of four crack-detection techniques: fast Haar transform (FHT), fast Fourier transform, Sobel, and Canny and shows that the FHT was significantly more reliable than the other three edge-detector techniques in identifying cracks.
Abstract: Bridge monitoring and maintenance is an expensive yet essential task in maintaining a safe national transportation infrastructure. Traditional monitoring methods use visual inspection of bridges on a regular basis and often require inspectors to travel to the bridge of concern and determine the deterioration level of the bridge. Automation of this process may result in great monetary savings and can lead to more frequent inspection cycles. One aspect of this automation is the detection of cracks and deterioration of a bridge. This paper provides a comparison of the effectiveness of four crack-detection techniques: fast Haar transform (FHT), fast Fourier transform, Sobel, and Canny. These imaging edge-detection algorithms were implemented in MatLab and simulated using a sample of 50 concrete bridge images (25 with cracks and 25 without). The results show that the FHT was significantly more reliable than the other three edge-detection techniques in identifying cracks.
635 citations
TL;DR: In this article, a system consisting of a laser source and a line-generating lens was used to optically slice the transparent synthetic soil models, and a digital camera was then used to capture images of the slices before and after deformation.
Abstract: Experimental models to measure spatial deformation patterns within a soil mass are typically limited by the fact that soil sensors do not provide a continuous image of the measured continuum. Additionally, soil sensors exhibit static and dynamic characteristics that are different from those of the surrounding soils and therefore can change the response of the measured continuum. The fundamental premise of this research is that transparent synthetic soil surrogates can be used to overcome these difficulties using digital image correlation (DIC). A system consisting of a laser source and a line-generating lens was used to optically slice the transparent synthetic soil models. A digital camera was used to capture images of the slices before and after deformation. This paper presents a new technique for quantifying spatial deformation throughout transparent synthetic soil models using DIC. The accuracy of the DIC technique was evaluated based on a scheme of predefined digital movement of synthetic soil images. Finally, a model consisting of a strip footing on a synthetic transparent soil is presented. The spatial deformations in the model are evaluated using the proposed DIC methodology and compared with the result of finite-element analysis.
103 citations
TL;DR: This paper employs the proposed sample space reduction and interpolation approach for thresholding pavement images based on the fact that the threshold values of gray-level pavement images are strongly related with the values of the mean and standard deviation of the pixel intensities.
Abstract: Real-time thresholding is very essential for real-time processing. In this paper, we use pavement crack detection as an example to explain the principle of the proposed approach. Conventional visual and manual analysis approaches to pavement crack detection are very costly, time-consuming, labor-intensive, and subjective. Real-time automated detection of pavement cracks will be very useful for pavement management. We employ the proposed sample space reduction and interpolation approach for thresholding pavement images. The main idea of the proposed approach is based on the fact that the threshold values of gray-level pavement images are strongly related with the values of the mean and standard deviation of the pixel intensities. The experimental results have demonstrated that the proposed approach can determine the threshold values accurately, reliably, robustly, quickly, and automatically. It can be applied to other real-time processing tasks as well.
103 citations
TL;DR: In this article, a computer-aided path planner for two crane lifts is presented, based on the type of movement of cooperative cranes in synchronous or asynchronous manner and the presence of trapping space.
Abstract: The use of cooperative cranes can improve the cost effectiveness of heavy lift operations. However, the complexity in developing a reliable lift plan prevents the widespread use of cooperative crane lifts. The availability of a computer-aided planning system can improve planning efficiency and reliability. Path planning is an important subtask of the lift planning process. This paper presents work done to develop a computer aided path planner for two crane lifts. Two heuristic search methods, hill climbing and A*, were implemented for automating the path-planning task. Search space was represented using the concept of configuration space. The effec- tiveness of the search methods was evaluated by solving three problems with increasing levels of complexity. The formulation of these problems was based on the type of movement of cooperative cranes ~in synchronous or asynchronous manner! and the presence of trapping space. It was found that while the hill climbing approach found feasible paths in a few seconds or minutes, these paths were far from optimal in situations containing trapping space. In contrast, the A * search resulted in near optimal paths, but the execution time was of the order of hours.
94 citations
TL;DR: Methods for representing domain knowledge, necessary for creating a general building design model, and techniques that permit the manipulation of both structural and architectural design aspects so that the power of the GA is effectively exploited to support the role of the designer as a decision maker are addressed.
Abstract: Issues relating to the application of the genetic algorithm (GA) to conceptual building design are addressed and designer support techniques are introduced. Particular attention is given to methods for representing domain knowledge, necessary for creating a general building design model, and techniques that permit the manipulation of both structural and architectural design aspects so that the power of the GA is effectively exploited to support the role of the designer as a decision maker. An example of a decision support system is presented, and its robustness and power of knowledge discovery are demonstrated by means of a parametric study. The role of human-computer interaction in knowledge discovery is also considered, both in the context of better understanding of the design domain and as a tool to increase user confidence in the outcome. This paper is addressed toward readers involved in conceptual building design who have basic knowledge of genetic algorithms.
71 citations
TL;DR: Two of the most widely used neuro-fuzzy models, namely: B-spline associative memory networks and adaptive network based fuzzy inference systems, are compared and their relative advantages are discussed using a mode choice modeling case study.
Abstract: This paper investigates the use of neuro-fuzzy models for behavioral mode choice modeling. The concept of neuro-fuzzy models has emerged in recent years as researchers have tried to combine the transparent, linguistic representation of a fuzzy system with the learning ability of artificial neural networks. Several neuro-fuzzy systems have been reported in the literature. They include various representations and architectures and therefore are suitable for different applications. In this paper, the performance of two of the most widely used neuro-fuzzy models, namely: B-spline associative memory networks and adaptive network based fuzzy inference systems, is compared. The theoretical backgrounds of both systems are presented and their relative advantages are discussed using a mode choice modeling case study. Areas of comparison include: model performance, dealing with the curse of dimensionality, automatic exclusion of irrelevant inputs, and model transparency.
65 citations
TL;DR: In this paper, an automated model for monitoring labor inputs, based on automated data collection (ADC), offers a solution to the problem of deviation from planned performance can only be reported after significant time has elapsed.
Abstract: In current project control practice, deviations from planned performance can only be reported after significant time has elapsed. Manual monitoring on construction sites is costly and error prone. Consequently, an automated model for monitoring labor inputs, based on automated data collection (ADC), offers a solution to the problem. Integration with a computerized building project model (BPM), including the physical geometry of the building, the resources active in its execution, and the planned construction activity schedule, is essential for the operation of such a model. Integration with an existing BPM requires that the BPM be expanded to support interpretation and accumulation of the monitoring results. To this end, appropriate project model classes and relationships have been implemented and tested. Experimental data were collected, using an ADC system, from the job site of a reinforced concrete building. The data were processed, within the BPM, with the aid of a prototypical location interpretation module.
63 citations
TL;DR: The ontology is formalized to represent estimators' rationale for relating features of building product models to construction activities and associated construction resources to calculate construction costs and validation studies of use provide evidence that the ontology enabled estimators to generate and maintain construction cost estimates more completely, consistently, and expeditiously than traditional tools.
Abstract: It is the cost estimator's task to determine how the building design influences construction costs. Estimators must recognize the design conditions that effect construction costs and adjust the project's activities, resources, and resource productivity rates accordingly to create a cost estimate for a particular design. Current tools and methodologies help estimators to establish relationships between product and cost information to calculate quantities automatically. However, they do not provide a common vocabulary to represent estimators' rationale for relating product and cost information. This paper presents the ontology we formalized to represent estimators' rationale for relating features of building product models to construction activities and associated construction resources to calculate construction costs. A software prototype that implements the ontology enables estimators to generate activities that know what feature requires their execution, what resources are being used and why, and how much the activities' execution costs. Validation studies of use of the prototype system provide evidence that the ontology enabled estimators to generate and maintain construction cost estimates more completely, consistently, and expeditiously than traditional tools.
62 citations
TL;DR: This paper demonstrates that it is feasible to use either the k-nearest-neighbor instance-based learning (IBL) technique or the inductive learning (IL) technique for engineering applications in classification/prediction problems such as estimating remaining service life of bridge decks.
Abstract: This paper demonstrates that it is feasible to use either the k-nearest-neighbor instance-based learning (IBL) technique or the inductive learning (IL) technique for engineering applications in classification/prediction problems such as estimating remaining service life of bridge decks. It is shown that IBL is more efficient than IL: The best achieved percentages of correctly classified instances are 50% as generated by k-nearest-neighbor IBL and 41.8% when generated by the C4.5/IL learning algorithm. From a machine learning (ML) standpoint both these values are considered low, but this is attributed to the fact that the deterioration model used to compute the remaining service life turned out to be inadequate. It is based on a methodology developed under the Strategic Highway Research Program (SHRP) for life-cost analysis of concrete bridges relative to reinforcement corrosion. Actual bridge deck surveys were obtained from the Kansas Department of Transportation that include the type of attributes needed for the SHRP methodology. The experimentation with the ML algorithms reported here also describes the experience one may go through when faced with an imperfect model, or with incomplete data or missing attributes.
57 citations
TL;DR: In this paper, two stochastic search methods, simulated annealing and probabilistic global search Lausanne, are applied to control the quasistatic displacement of a tense-grity structure with multiple objectives and interdependent actuator effects.
Abstract: Many engineering tasks involve the search for good solutions among many possibilities. In most cases, tasks are too complex to be modeled completely and their solution spaces often contain local minima. Therefore, classical optimization techniques cannot, in general, be applied effectively. This paper studies two stochastic search methods, one well-established (simulated annealing) and one recently developed (probabilistic global search Lausanne), applied to structural shape control. Search results are applied to control the quasistatic displacement of a tensegrity structure with multiple objectives and interdependent actuator effects. The best method depends on the accuracy related to requirements defined by the objective function and the maximum number of evaluations that are allowed.
56 citations
TL;DR: In this paper, the authors present an approach adopted in the development of a multiagent system for construction claims negotiation (MASCOT) and discuss the choice of an appropriate negotiation mechanism for MASCOT.
Abstract: Negotiation is an important aspect of the construction process. Different negotiation theories and models are available and have been deployed in a variety of situations. In some cases, these have been incorporated into multiagent systems that address a number of engineering problems. This paper is concerned with the approach adopted in the development of a multiagent system for construction claims negotiation (MASCOT). It reviews the key negotiation theories, outlines the peculiarities of the domain (construction claims negotiation), and discusses the choice of an appropriate negotiation mechanism for MASCOT. Of particular interest is the integration of Zeuthen’s bargaining model with a Bayesian learning mechanism, which addresses the characteristics of construction claims negotiation. An example is presented to demonstrate the application of the MASCOT model in a real construction claim case.
TL;DR: In this article, an agent-based compensatory negotiation methodology is proposed to facilitate the distributed coordination of project schedule changes, where a project can be rescheduled dynamically through negotiations by all of the concerned subcontractors.
Abstract: Change is ubiquitous in construction project schedules and there are many interrelationships and interdependencies in project schedule changes. Therefore, a schedule change in the work of a subcontractor might affect schedules of other subcontractors, as well as the project deadline. The subcontractor should resolve schedule conflicts with other affected subcontractors. This implies that there is a need for a methodology for the distributed coordination of project schedule changes (DCPSC). This paper presents a novel agent-based compensatory negotiation methodology to facilitate the DCPSC wherein a project can be rescheduled dynamically through negotiations by all of the concerned subcontractors. The methodology consists of a compensatory negotiation strategy based on utility of timing, multilinked negotiation protocols, and message-handling mechanisms. A simple case example illustrates the methodology. The methodology makes new contributions in both theoretical and practical areas. In practice, this methodology will improve project network schedules, by lowering the sum of the cost of the subcontractors associated with their resource constraints. In theory, the methodology provides a distributed coordination methodology that can improve interaction and collaboration among agents and people.
TL;DR: The application of fuzzy logic to discrete event simulation in dealing with uncertainties of construction operations and the impact of flexible demand of resources on productivity is described.
Abstract: This paper describes the application of fuzzy logic to discrete event simulation in dealing with uncertainties of construction operations. The uncertainties in the quantity of resources required to activate an activity are modeled with fuzzy sets in linguistic terms. The fuzzy logic if-then rule is built to control the activation of activities. The duration of the activity that varies with the quantities of resources involved is determined through the fuzzy logic rule-based model. The fuzzy logic control of activities is incorporated with the activity scanning simulation strategy to implement the fuzzy simulation system for construction operations. In addition, the fuzzy activity element is adopted in the graphical modeling process. Examples are given that illustrate uses of the fuzzy simulation system and the impact of flexible demand of resources on productivity.
TL;DR: The capability of an artificial neural network to provide a data-driven approximation of the explicit relation between transmissivity and hydraulic head as described by the groundwater flow equation is demonstrated and how such an approximation can be used for the purpose of parameter estimation in groundwater hydrology is explained.
Abstract: The capability of artificial neural networks to act as universal function approximators has been traditionally used to model problems in which the relation between dependent and independent variables is poorly understood. In this paper, the capability of an artificial neural network to provide a data-driven approximation of the explicit relation between transmissivity and hydraulic head as described by the groundwater flow equation is demonstrated. Techniques are applied to determine the optimal number of nodes and training patterns needed for a neural network to approximate groundwater parameters for a simulated groundwater modeling case study. Furthermore, the paper explains how such an approximation can be used for the purpose of parameter estimation in groundwater hydrology.
TL;DR: An improved Bug-based algorithm, called SensBug, is presented, which can produce an effective path in an unknown environment with both stationary and movable obstacles and an improved method to select local directions, a reverse mode, and a simple leaving condition.
Abstract: In developing an intelligent mobile construction robot, a navigation system that can provide an effective and efficient path-planning algorithm is a very important element. The purpose of a path-planning method for a mobile construction robot is to find a continuous collision-free path from the initial position of the construction robot to its target position. This paper presents an improved Bug-based algorithm, called SensBug, which can produce an effective path in an unknown environment with both stationary and movable obstacles. The contributions, which make it possible to generate an effective and short path, are an improved method to select local directions, a reverse mode, and a simple leaving condition. Some emerging technologies that can be used for implementing an intelligent construction robot are introduced in this paper. DOI: 10.1061/~ASCE!0887-3801~2003!17:2~97! CE Database subject headings: Construction planning; Automation; Earthwork; Robotics.
TL;DR: The purpose of this study was to determine the accuracy of D TM profile data based on scattered data points for several gridding methods and recommends using interpolations of minimum curvature and multiquadric curvature for more accurate DTM profile data.
Abstract: Various forms of data such as profile, cross section, volume, height, and surface area can be derived from the digital terrain model (DTM). Although many research studies were carried out on the accuracy of the DTM, especially on grid data-based DTMs and on the effect of the grid size or grid resolution, the accuracy of profile data derived from a scattered data-based DTM and the effect of the gridding (interpolation) method on the accuracy of the profile data derived are still unfamiliar to many DTM producers and users. Therefore, the purpose of this study was to determine the accuracy of DTM profile data based on scattered data points for several gridding methods. Linear interpolation in triangles and interpolations of Sibson (natural neighbor), nearest neighbor, weighted average, polynomial, multiquadric, and minimum curvature were tested on five theoretical test surfaces. After 1-m grid DTMs were generated using the gridding methods mentioned above, nine different profile data in the y direction for each test surface and for each gridding method were derived from the DTMs. The standard deviation of each profile for each gridding method was derived by differences between true and interpolated profile values. As a result of the case study, the author recommends using interpolations of minimum curvature and multiquadric curvature for more accurate DTM profile data.
TL;DR: The results show that this new model, MAGP, is better than the traditional proportional selection GP for HPC strength estimation, and could improve the capability of searching global optima and avoid premature convergence during the selection process of GP.
Abstract: This technical note is aimed at demonstrating a mixture-proportioning problem, which uses the macroevolutionary algorithm (MA) combined with genetic programming (GP) to estimate the compressive strength of high-performance concrete (HPC). GP provides system identification in a transparent and structured way; a fittest function type of experimental results will be obtained automatically from this method. MA is a new concept of species evolution at the higher level. It could improve the capability of searching global optima and avoid premature convergence during the selection process of GP. In the study, two appropriate functions have been found to represent the relationships between different ingredients and the compressive strength. The results show that this new model, MAGP, is better than the traditional proportional selection GP for HPC strength estimation.
TL;DR: In this article, the authors describe a research project to examine the use of evolutionary computing techniques for the design of commercial office-type buildings, and the benefits gained from their evaluation of the software are considered.
Abstract: Research into computer-assisted design is often undertaken with relatively little input from practicing designers. Without such involvement, one can argue that the techniques developed are not subjected to any form of evaluation or independent scrutiny and thus the methodology is wanting in terms of scientific rigor. The paper describes a research project to examine the use of evolutionary computing techniques for the design of commercial office-type buildings. The research has involved a considerable amount of input from designers, and the contributions that they make to the research are identified and discussed. In particular, the benefits gained from their evaluation of the software are considered. Also, the possible pitfalls regarding such an approach to research are identified.
TL;DR: In this article, a conceptual framework for the construction management practice that serves as the foundation for the development of situational simulations is introduced, where temporally dynamic clinical exercises with the objective of exposing participants to rapidly unfolding events and the pressure of decision making.
Abstract: Construction managers are decision makers who administer nontrivial processes. The replacement of highly experienced construction managers and other construction professionals is a laborious process for the industry. This paper introduces a conceptual framework for the construction management practice that serves as the foundation for the development of situational simulations. Situational simulations are temporally dynamic clinical exercises with the objective of exposing participants to rapidly unfolding events and the pressure of decision making. The application of situational simulations provides construction managers and other decision makers the opportunity of experiencing and responding to risky events without endangering the success of real projects, further enhancing their decision-making skills. The construction management conceptual framework includes a process, a product, and an information model. The analysis of a basic mathematical representation of the process model is the focus of this paper.
TL;DR: A mediation-based framework that enables information clients to calibrate the source information services to the clients’ characteristics is introduced, and an infrastructure that is particularly suitable for the integration of engineering services is illustrated.
Abstract: This paper describes a software framework for the development of a ubiquitous computing environment for distributed engineering information services. Two fundamental issues are addressed: universal...
TL;DR: A Web-based geographic information system (GIS) that can delineate watersheds in real time was developed for use in hydrologic analysis and to support hydrologics model operation on the Internet.
Abstract: A Web-based geographic information system (GIS) that can delineate watersheds in real time was developed for use in hydrologic analysis and to support hydrologic model operation on the Internet. The system integrates a watershed delineation (WD) engine, common gateway interfaces, a Web-GIS user interface, and supports digital spatial data including vector and grid formats. The WD program utilizes a double-seed array-replacement algorithm to obtain a watershed boundary from point coordinates. The system provides a user interface for the selection of an outlet point from a map display in the Web browser using MapServer Web-GIS capability. The WD and data extraction system has been implemented for all of Indiana, with extensive verification conducted in the 2,082.7 km2 Wildcat Creek watershed in Indiana. The time to obtain results and the quality of results are acceptable for use as a real-time system for WD via the Web.
TL;DR: A partial solution to the difficult problem of developing field inspection support systems is presented—a modular and customizable software environment to facilitate the construction of such applications.
Abstract: In order to provide useful and practical computing support for inspectors in the field performing inspection activities, computer systems have to be designed and customized to recognize the specific task and context of the inspection. Unfortunately, the development of field inspection support systems is difficult and still suffers from a lack of more general design knowledge. Effort is wasted when implementing different applications that share some common aspects. This paper presents a partial solution to the difficult problem of developing field inspection support systems—a modular and customizable software environment to facilitate the construction of such applications.
TL;DR: In this article, a centralized multiclient cooperative contractor registration (CMCCR) system is proposed using web-based technology, which provides a powerful communication medium with a high potential for satisfying the above requirements.
Abstract: Despite perceived industry needs for developing a centralized contractor registration (CCR) system, such a system is still to be developed for a multiclient environment such as Hong Kong. A major barrier is that such a CCR system must be relatively easy to access to ensure that (i) contractors' information is constantly updated (by contractors), (ii) contractors' performance is reported promptly (by project teams and occupiers), and (iii) the latest analyzed information is available to any authorized clients anytime anywhere. A centralized multiclient cooperative contractor registration (CMCCR) system is proposed using web-based technology, which provides a powerful communication medium with a high potential for satisfying the above requirements. The conceptual framework of the proposed CMCCR system is presented, and the concept is illustrated through a prototype based on information collected in Hong Kong. The initial observations indicate that web-based technology is suitable for the proposed CMCCR system, and that the development of a fully functional web-based CMCCR is both feasible and useful.
TL;DR: In this paper, a new CRMS called CBROOF is developed within the Building Envelope Life Cycle Asset Management (BELCAM) research project to overcome some limitations that affect their ability to efficiently represent roof data at different manageable levels and to accurately predict the service life of various roof components.
Abstract: Computerized roof management systems (CRMSs) are developed to assist building owners in minimizing their expenditures on roof maintenance while improving the safety and serviceability of their roof stock. Current CRMSs have some limitations that affect their ability to efficiently represent roof data at different manageable levels and to accurately predict the service life of various roof components. A new CRMS, called CBROOF, is developed within the Building Envelope Life Cycle Asset Management (BELCAM) research project to overcome these limitations. CBROOF has an object-oriented conceptual model that supports the hierarchical decomposition of roofs and the representation of their data at different levels of detail. CBROOF also incorporates the use of the case-based reasoning (CBR) approach to predict the future condition of roof components based on the recorded condition of similar components. The design and implementation of the relevant modules of CBROOF are presented, and the CBR deterioration model developed for the service life prediction of built-up roof membranes is validated.
TL;DR: This paper presents an object-oriented (OO) software framework for computer-aided structural analysis and design research, where different structural analysis methods and design procedures need to be implemented and investigated.
Abstract: This paper presents an object-oriented (OO) software framework for computer-aided structural analysis and design research, where different structural analysis methods and design procedures need to be implemented and investigated. The framework is designed with four basic modules: structure, load, analysis, and design. Each module includes a set of cooperating interfaces and classes. Through the predefined interfaces, the framework provides architecture for many structural design applications. A variety of similar entities, such as different design applications, design procedures, and analysis methods, can be built on this architecture by implementing the necessary interfaces. The clearly defined interactions between the modules accommodate the future extensions within the modules. The final OO design of the framework can be communicated by many well-known design patterns, and it is described by unified modeling language. The framework is then customized to the application for optimizing the configuration ...
TL;DR: In this article, the authors discuss the need for inclusion of construction as-built data in the bridge management database along with the periodic inspection and maintenance data, and demonstrate the proper design of an asbuilt information management model and system that is integrated with existing standard bridge management systems.
Abstract: The transportation infrastructure is key to economic development in the United States. Providing a high level of serviceability through periodic inspection and maintenance is important in keeping the transportation system operational and in avoiding major replacement efforts. Of particular importance is the inventory of bridges in the national transportation infrastructure, due to their high cost and direct impact on public safety. The focus of this paper is on information management in support of bridge maintenance functions. Particularly, the research project discussed in the paper addresses the need for inclusion of construction as-built data in the bridge management database along with the periodic inspection and maintenance data. Attention to this type of data has been lacking. Therefore, the paper promotes bridge as-built data, discusses its role in bridge management, and demonstrates the proper design of an as-built information management model and system that is integrated with existing standard bridge management systems such as Pontis.
TL;DR: This paper investigates the use of wrapper methods for bagging, boosting, and feature selection to improve the prediction accuracy of the decision tree algorithm and revealed that the improvement obtained by the feature selection method can be misleading.
Abstract: The decision tree algorithm is one of the most common techniques of inductive learning This paper investigates the use of wrapper methods for bagging, boosting, and feature selection to improve the prediction accuracy of the decision tree algorithm A set of concrete bridge decks is extracted from the Kansas bridge database, and the deterioration of the health index is selected as the decision/class value for induction From the conducted experiments, the decision tree accuracy obtained is 677%, whereas bagging and the boosting gave 734% and 727%, respectively Wrapping with a feature selection method gave an accuracy of 750% If feature selection method is applied first, bagging and boosting do not provide any further improvement to the decision tree algorithm A series of tests were conducted where the selected features were examined and manually eliminated for the data set This revealed that the improvement obtained by the feature selection method can be misleading For the problem at hand, the a
TL;DR: The fuzzy outcome of the conflict among the populations guides the evolution of the different GAs toward better solutions in the statistical sense and the proposed scheme is applied to two different problems—a multimodal function with six global and several near-global optima, and a reliability based optimal design of a simple truss.
Abstract: Competition is introduced among the populations of a number of genetic algorithms ~GAs! in solving optimization problems The aim is to adapt the parameters of the GAs, by altering the resources of the system, so as to achieve better solutions The evolution of the different populations, having different sets of parameters, is controlled at the level of metapopulation, ie, the union of populations, on the basis of statistics and trends of the evolution of every population An overall fitness measure is introduced that incorporates a diversity measure and the required resources to rank the populations The fuzzy outcome of the conflict among the populations guides the evolution of the different GAs toward better solutions in the statistical sense The proposed scheme is applied to two different problems—a multimodal function with six global and several near-global optima, and a reliability based optimal design of a simple truss Numerical results are presented, and the robustness and computational efficiency of the proposed scheme are discussed
TL;DR: By carefully controlling quality of both the roadway linework data and the elevation data, GIS programs can be written to provide accurate length measurements to the transportation community.
Abstract: Data quality and spatial data accuracy issues are critical to any geographic information systems ~GIS! application, especially GIS applications in the transportation community. This paper addresses one specific aspect of spatial data accuracy issues, namely, linear measurement ~length measurement!, through a transportation case study. In the case study, an alternative to distance measurement instruments ~DMI! was proposed to determine road lengths for interstate highways in North Carolina. In the proposed alternative, the road lengths were calculated by overlaying GIS roadway linework over elevation data—in this case the National Elevation Dataset, which was developed based on U.S. Geological Survey 7.5 min digital elevation models and calculating a centerline roadway slope distance. The results of this approach were collected and compared with DMI lengths to assess the accuracy of the proposed approach. Error sources were tentatively identified and control mechanisms were discussed. Computer tools and models used to model surfaces and roadway linework are emphasized in this paper. The computer algorithms used for length calculations and accuracy assessment are described. This research concluded that, by carefully controlling quality of both the roadway linework data and the elevation data, GIS programs can be written to provide accurate length measurements to the transportation community. Furthermore, instrumentation like global positioning systems, high resolution cameras, and precise odometers can be combined to create productivity enhancing automated engineering systems.