Browsing by Author "Kao, JJ"

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A Fuzzy Markov approach for assessing groundwater pollution potential for landfill siting
(2002-04-01)
Chen, WY
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Kao, JJ
;
環境工程研究所
;
Institute of Environmental Engineering
This Study presents a Fuzzy Markov groundwater Pollution potential assessment approach to facilitate landfill siting analysis. Landfill siting is constrained by various regulations and is complicated by the uncertainty of groundwater related factors. The conventional static rating method cannot properly depict the potential impact of Pollution on a groundwater table because the groundwater table level fluctuates. A Markov chain model is a dynamic model that can be viewed as a hybrid of probability and matrix models. The probability matrix of the Markov chain model is determined based on the groundwater table elevation time series. The probability reflects the likelihood of the groundwater table changing between levels. A fuzzy set method is applied to estimate the degree of pollution potential, and a case study demonstrates the applicability of the proposed approach. The short- and long-term pollution potential information provided by the proposed approach is expected to enhance landfill siting decisions.
A multiobjective model for non-point source pollution control for an off-stream reservoir catchment
(2003)
Kao, JJ
;
Chen, WJ
;
環境工程研究所
;
Institute of Environmental Engineering
Phosphorus loads from agricultural non-point source pollution (NPSP) significantly degrade reservoir water quality, making adequate control of agricultural NPSP necessary for improving the water quality. Controlling NPSP is generally accomplished using various Best Management Practices (BMPs). The present study applies the Agricultural Non-Point Source Pollution (AGNPS) model to simulate NPSP loading and BMP efficiencies and establishes an enhanced multiobjective mixed-integer programming model for NPSP control strategy analyses based on these results. Cost, phosphorus load, sediment load and equity are the four major objectives considered. A case study for the Posan reservoir is presented. Four commonly proposed and applicable BMPs are chosen. Non-inferior solutions obtained using the constraint method and trade-off relationships among different control objectives are described and discussed. Compared with a previously proposed fertilizer control model, results show that the model established herein is more cost-effective and achieves better phosphorus and sediment loading reduction and equity goals. Furthermore, the current model is expected to facilitate decision-making analysis for development of an appropriate cost-sharing program to encourage adoption of appropriate BMPs by farmers.
A raster-based C program for siting a landfill with optimal compactness
(1996-10-01)
Kao, JJ
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
;
Institute of Environmental Engineering
Landfill siting requires performing spatial analyses for various factors to evaluate site suitability. A geographical information system, although capable of effectively manipulating spatial data, lacks the capability to locate an optimal site when compactness and other factors are considered simultaneously. In our previous work, a mixed-integer compactness model was proposed to overcome this difficulty. However, computational time with a conventional mixed-integer programming package for solving the model is time consuming and impractical. Therefore, in this work, a C program is developed, based on a proposed raster-based branch-and-bound algorithm. The program can implement multi-factor analyses for compactness and other siting factors with weights prespecified by the user. An example is provided to demonstrate the effectiveness of the program. Copyright (C) 1996 Elsevier Science Ltd
A raster-based C program for siting a landfill with optimal compactness
(1996-10-01)
Kao, JJ
;
環境工程研究所
;
Institute of Environmental Engineering
Landfill siting requires performing spatial analyses for various factors to evaluate site suitability. A geographical information system, although capable of effectively manipulating spatial data, lacks the capability to locate an optimal site when compactness and other factors are considered simultaneously. In our previous work, a mixed-integer compactness model was proposed to overcome this difficulty. However, computational time with a conventional mixed-integer programming package for solving the model is time consuming and impractical. Therefore, in this work, a C program is developed, based on a proposed raster-based branch-and-bound algorithm. The program can implement multi-factor analyses for compactness and other siting factors with weights prespecified by the user. An example is provided to demonstrate the effectiveness of the program. Copyright (C) 1996 Elsevier Science Ltd
A vector-based spatial model for landfill siting
(1998-02-01)
Lin, HY
;
Kao, JJ
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環境工程研究所
;
Institute of Environmental Engineering
An inappropriate landfill site may have negative environmental, economic or ecological impacts. Therefore, landfill siting should carefully consider various factors and regulations and evaluate a significant amount of spatial data. However, processing of spatial information for various siting factors is tedious. Digitized data is thus frequently used for improving data processing and analysis efficiency. Vector-based data are composed of points, lines and polygons, which express gee-referenced attributes of the real world. Compared to raster-based data, although describing real world spatial information more precisely, the lack of uniformity makes vector-based data difficult to use with a mathematical optimization model. In this study, a mixed-integer spatial optimization model is developed based on vector-based data to assist decision makers in finding a suitable site from a siting area. Major factors considered in the model include impacts on the environment, economic efficiency, and site compactness. A sample case is provided to demonstrate the effectiveness of the model. (C) 1998 Elsevier Science B.V.
A Xerion-based Perl program to train a neural network for grid pattern recognition
(1996-11-01)
Kao, JJ
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交大名義發表
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環境工程研究所
;
National Chiao Tung University
;
Institute of Environmental Engineering
Neural network training with the back propagation algorithm is an important artificial intelligence technique for grid pattern recognition. The training is time-consuming however and generally requires a trial-and-error procedure to configure the network. A Perl program executed with Xerion is presented to relieve the;training burden. Statistical reports such as computation time, learning performance, and validation performance are generated automatically by the program. A case study applying the program for training networks to determine a drainage pattern from Digital Elevation Model data is demonstrated and discussed. Manually determining drainage patterns from topographical maps for a grid-based model is tedious and subjective. The neural network has a self-learning capability that can replace human judgment involved in the conventional approach. Copyright (C) 1996 Elsevier Science Ltd.
An educational water quality management game
(1996)
Kao, JJ
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Chen, YJ
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交大名義發表
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環境工程研究所
;
National Chiao Tung University
An educational game for water quality management is developed to assist a novice engineer or student to learn the compromises among three major objectives to manage water quality: cost, water quality, and equity. A window-based interface is developed on a microcomputer. A hypothetical example with four dischargers is used in the program, and the initial scenario is based on a uniform treatment scheme. The player acts as the manager of a water quality authority to design the best compromise policy. The friendly interfaces allows one to exercise judgment in selecting and in modifying discharge permit programs. The design and development of the game and related computer program are described. Network accessibility has provided a novel environment for remote education. A prototypical multimedia network interface is provided for local or foreign remote access to the game. Copyright (C) 1996 IAWQ.
An expert system for selecting and sequencing wastewater treatment processes
(1996)
Yang, CT
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Kao, JJ
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交大名義發表
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環境工程研究所
;
National Chiao Tung University
Wastewater treatment system design involves selecting and sequencing various treatment processes. The design becomes complicated when a large number of processes and various contaminants are considered. In this work, an expert system is developed to find an appropriate treatment process design for a given waste stream. The knowledge base of the system is established with a treatability database to select suitable treatment techniques for specified contaminants and concentration levels. Also, a preliminary fuzzy logic based approach is proposed to express the user's preference of treatment techniques in a linguistic farm. The preference is defined on the basis of the treatment efficiency and the cost of a technique. The system is intended to serve as a decision support tool for a designer to determine optimal treatment process sequences for various contaminants at different concentration levels. Finally, the developed system is demonstrated in a case study for a chemical processing waste stream. Copyright (C) 1996 IAWQ. Published by Elsevier Science Ltd.
Dynamic spatial modeling approach for estimation of internal phosphorus load
(1998-01-01)
Kao, JJ
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Lin, WL
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Tsai, CH
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環境工程研究所
;
Institute of Environmental Engineering
The effect of the pollution load generated internally from a reservoir on the effectiveness of an eutrophication control plan is significant and has gained increasing attention recently. Accurate estimation of the internal load is difficult because of its spatial and temporal variation. A procedure using a dynamic spatial modeling approach is proposed to improve the estimation. A case study of Posan off-stream reservoir is described to demonstrate the implementation of the procedure for data collection and model preparation, field sampling planning and investigation, laboratory analysis for phosphorus releasing rates, model integration of AGNPS and WASP, calibration and verification of the integrated model, and the internal load estimation. The procedure is expected to provide appropriate temporal and spatial phosphorus internal load estimation for an off-stream reservoir. (C) 1998 Elsevier Science Ltd. All rights reserved.
Dynamic spatial modeling approach for estimation of internal phosphorus load
(1998-01-01)
Kao, JJ
;
Lin, WL
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Tsai, CH
;
環境工程研究所
;
Institute of Environmental Engineering
The effect of the pollution load generated internally from a reservoir on the effectiveness of an eutrophication control plan is significant and has gained increasing attention recently. Accurate estimation of the internal load is difficult because of its spatial and temporal variation. A procedure using a dynamic spatial modeling approach is proposed to improve the estimation. A case study of Posan off-stream reservoir is described to demonstrate the implementation of the procedure for data collection and model preparation, field sampling planning and investigation, laboratory analysis for phosphorus releasing rates, model integration of AGNPS and WASP, calibration and verification of the integrated model, and the internal load estimation. The procedure is expected to provide appropriate temporal and spatial phosphorus internal load estimation for an off-stream reservoir. (C) 1998 Elsevier Science Ltd. All rights reserved.
Effects of seasonal variation in precipitation on estimation of non-point source pollution
(2003)
Lin, YC
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Kao, JJ
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環境工程研究所
;
Institute of Environmental Engineering
The extent of nonpoint source pollution (NPSP) generated from upstream catchment areas of a reservoir is normally estimated based on a design rainfall. However, rainfall generally varies in different seasons. This seasonal change may significantly influence the estimation of runoff volume and associated NPSP arising within a reservoir watershed. The NPSP management, reservoir operation, and water treatment operation strategies developed based on the estimation will also be altered. This study analyzes the effects of monthly and seasonal variation in precipitation on the estimation of pollution levels from nonpoint sources in a reservoir watershed. The area studied is the Derchi reservoir watershed located in central Taiwan. This watershed is subdivided into twenty-six sub-watersheds, and the Thiessen method is used. to determine the rainfall intensity in each sub-watershed. Runoff pattern and NPSP contributions for each sub-watershed are estimated using the AGNPS model. Results show significant seasonal variation in precipitation; estimated NPSP loads likewise vary significantly over time. Seven- to one hundred-fold differences among monthly and seasonal estimations of phosphorus and sediment loads are observed.
Enhanced spatial model for landfill siting analysis
(1999-09-01)
Lin, HY
;
Kao, JJ
;
環境工程研究所
;
Institute of Environmental Engineering
A landfill siting analysis typically requires evaluating various rules, factors, constraints, and numerous spatial data. A modern geographical information system, although capable of rapidly processing a massive amount of spatial data, lacks the ability to locate an optimal site when compactness and other factors are simultaneously evaluated. A previously developed grid-based model could not be applied to resolve this inability for irregularly shaped spatial data. Therefore, an enhanced spatial siting model is proposed herein for general spatial data. A compactness index is applied to ensure the integrity of selected sites. Two case studies are presented to demonstrate the applicability of the proposed model. The proposed model and two models developed previously are compared in the first case study based on the single factor of land cost. A single factor model is perhaps quite unacceptable with respect to other factors. The second case study is thus presented to demonstrate the flexibility of the model for considering additional factors, land slope, and road network accessibility. Moreover, results obtained from various models and siting factors are compared and discussed.
Forecasts using neural network versus Box-Jenkins methodology for ambient air quality monitoring data
(2000-02-01)
Kao, JJ
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Huang, SS
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環境工程研究所
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Institute of Environmental Engineering
This study explores ambient air quality forecasts using the conventional time-series approach and a neural network. Sulfur dioxide and ozone monitoring data collected from two background stations and an industrial station are used. Various learning methods and varied numbers of hidden layer processing units of the neural network model are tested. Results obtained from the time-series and neural network models are discussed and compared on the basis of their performance for 1-step-ahead and 24-step-ahead forecasts. Although both models perform well for 1-step-ahead prediction, some neural network results reveal a slightly better forecast without manually adjusting model parameters, according to the results. For a 24-step-ahead forecast, most neural network results are as good as or superior to those of the time-series model. With the advantages of self-learning, self-adaptation, and parallel processing, the neural network approach is a promising technique for developing an automated short-term ambient air quality forecast system.
Fuzzy GIS assisted landfill siting analysis
(1996)
Lin, HY
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Kao, JJ
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Li, KC
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Hwang, HY
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交大名義發表
This paper presents a prototypical fuzzy geographical information system (GIS) developed to facilitate landfill siting analysis. Landfill siting requires extensive effort to process massive spatial information, to evaluate various factors, and to review numerous criteria and regulations. A computerized GIS, although capable of effectively manipulating spatial information, generally lacks the ability to evaluate the suitability levers of candidate sites based on factors/criteria with some degree of imprecision and/or uncertainty. Because of their imprecision/uncertainty, many siting factors/criteria are not appropriate to be evaluated with a binary assessment, e.g., yes/no. Fuzzy set algorithms are therefore applied to overcome this difficulty. With proper membership functions assigned to imprecise/uncertain factors/criteria, the suitability score of a candidate site can be determined by a series of fuzzy calculations. The algorithms are incorporated into a previously developed landfill siting GIS to assist an engineer in improving siting decisions. This article, in addition to the description of the prototype, presents a case study to demonstrate the effectiveness of the developed Fuzzy GIS.
Grid-based heuristic method for multifactor landfill siting
(2005-10-01)
Lin, HY
;
Kao, JJ
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環境工程研究所
;
Institute of Environmental Engineering
Siting a landfill requires the processing of a large amount of spatial data. However, the manual processing of spatial data is tedious. A geographical information system (GIS), although capable of handling spatial data in siting analyses, generally lacks an optimization function. Optimization models are available for use with a GIS, but they usually have difficulties finding the optimal site from a large area within an acceptable computational time, and not easily directly available with a raster-based GIS. To overcome this difficulty, this study developed a two stage heuristic method. Multiple factors for landfill siting are considered and a weighted sum is computed for evaluating the suitability of a candidate site. The method first finds areas with significantly high potentialities and then applies a previously developed mixed-integer programming model to locate the optimal site within the potential areas, and can significantly reduce the computational time required for resolving a large siting problem. A case study was implemented to demonstrate the effectiveness of the proposed method, and a comparison with the previously developed model was provided and discussed.
IAC network for composition of waste-incineration facility
(1996-04-01)
Kao, JJ
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Liao, YY
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環境工程研究所
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Institute of Environmental Engineering
This research explores a prototypical interactive activation and competition (IAC) network to facilitate the selection of an appropriate facility combination for municipal solid waste incineration on the basis of characteristics of waste streams. Waste of types treatable with a specific facility combination was also evaluated. A prototypical IAC network was developed with a knowledge base constructed from five data sources: waste characteristics, air-pollution-control devices, pretreatment units, flue gas cooling types, and combustion-chamber types. Unlike a traditional database or a rule base, questions with incomplete information can be answered by the IAC network. This advantage greatly helps an engineer screen a sound facility combination for a specified waste stream with some degree of uncertainty. The prototype can be used also by a waste authority to preliminarily evaluate waste facility construction permit applications, by a novice engineer to learn the appropriate usage of a facility, and by an incinerator manager to preliminarily evaluate treatable waste.
Multifactor spatial analysis for landfill siting
(1996-10-01)
Kao, JJ
;
Lin, HY
;
交大名義發表
;
環境工程研究所
;
National Chiao Tung University
Siting a landfill typically requires processing a significant amount of spatial data with respect to various siting rules, regulations, factors, and constraints. Manually performing such a spatial analysis with drawing tools is generally tedious. A modern geographical information system (GIS), although capable of manipulating spatial data to facilitate the analysis, lacks the ability to locate an optimal site when compactness and other factors are simultaneously considered. An appropriate siting model was therefore explored for use with a raster-based GIS. A mixed-integer programming model was developed to obtain a site with optimal compactness. A comparison was made between the model and two other previously proposed models in terms of their applicability and simplicity for raster-based data. The compactness model was further extended to include multiple siting factors with weights determined using map layer analysis functions provided by a GIS. This multifactor model was applied to analyze the effects of varied weights and factors on making a siting decision.
Multimedia network system for landfill siting
(1998)
Kao, JJ
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環境工程研究所
;
Institute of Environmental Engineering
This paper describes a series of studies for developing a computerized multimedia network system for landfill siting. Siting analysis for a municipal solid waste landfill is a complex process. Various siting factors and criteria must be carefully analyzed. The landfill capacity crisis is a critical environmental issue to be resolved in many local communities in Taiwan, R.O.C. Appropriate inexpensive computerized tools capable of facilitating the siting analyses are therefore explored in this work. Several sub-systems including a computerized guideline, a geographical information system, a prototypical expert system, spatial optimization and multifactor models and a multimedia network interface had been developed. The entire structure of the system is described in this article, with discussions for the design and development of all sub-systems. The system is made available for 24-hour access from anywhere on the Internet. This networking capability allows a user without tools to utilize the system and to avoid the cost of system installation and training appropriate personnel to manage the system.
Multiobjective zone TP reduction analyses for an off-stream reservoir
(1997-07-01)
Kao, JJ
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Tsai, CH
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環境工程研究所
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Institute of Environmental Engineering
Multiobjective linear programming (MOLP) models are developed to evaluate total phosphorus (TP) load reduction strategies for an off-stream reservoir. Cost, water quality, and equity are the three major objectives considered. Watershed-based, subwatershed-based, and equal-transport-path-length-based strategies are the three zone control strategies analyzed and compared. The agricultural nonpoint-source pollution (AGNSP) model is used to simulate the non-point-source pollution loads on the reservoir, A twostep modeling procedure is applied to verify sediment mass balance and water quality of storm runoff. MOLP models are established based on the simulation results for the three control strategies and are solved using the ADBASE package to generate the noninferior solution sets of the models. The subwatershed-based control strategy is observed to be the most cost-effective one based on results obtained for TP concentration between 13 and 20 ppb, With respect to equity, however, the watershed-based control strategy is superior to the others. The proposed multiobjective analyses are intended to improve the comparison and evaluation of nonpoint source pollution control strategies.
Network expert geographic information system for landfill siting
(1996-10-01)
Kao, JJ
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Chen, WY
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Lin, HY
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Guo, SJ
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環境工程研究所
A prototypical network expert geographic information system (GIS) is developed to facilitate municipal solid waste landfill siting. A forward chaining knowledge base consisting of related siting rules extracted from various literature is used to establish an expert system. Siting analysis is performed by a GIS and evaluated by rules triggered from the expert system. The expert system and GIS are integrated into an expert GIS to combine the advantages of both systems. Also, a multimedia network interface is designed for local or remote access to the system from anywhere on the Internet. With the interface, a general user does not require previous knowledge of the expert system and GIS to use the system. This networking capability not only significantly reduces the cost of distributing tools to each user, but also avoids the difficulty that each user may encounter in installing and managing tools on the computer. Finally, a case study is provided to demonstrate the effectiveness of the developed system in facilitating landfill-siting analysis. The system can be directly accessed via Internet from the home page http://ev004.ev.nctu.edu.tw/ENGLISH/wsite/index.html.