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1.
Han-Keng Lee Yir-Yarn Yeh Wei-Ming Chen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(1):1-13
This study conducts risk assessment for an array of health effects that may result from exposure to disinfection by-products (DBPs). An analysis of the relationship between exposure and health-related outcomes is conducted. The trihalomethanes (THMs) species have been verified as the principal DBPs in the drinking water disinfection process. The data used in this study was collected from the Taiwan Water Corporation (TWC) from 1998 to 2002. Statistical analysis, multistage of Benchmark model, Monte Carlo simulation (MCS) and sensitive analysis were used to estimate the cancer risk analysis and assessment. This study included the statistical data analysis, epidemiology investigation and cancer risk assessment of THMs species in drinking water in Taiwan. It is more significant to establish an assessment procedure for the decision making in policy of drinking water safety predominantly. 相似文献
2.
Three standard methodological approaches used for carcinogenic risk assessment of the four trihalomethanes (THMs) species: Dibromochloromethane (CHClBr2), Bromodichloromethane (CHCl2Br), Bromoform (CHBr3) and Chloroform (CHCl3), in water collected from public water supplies which included main water source (raw water of the Tigris River), water treatment plants (treated water) and distribution system (tap water) in Baghdad City. The total concentration of THMs ranged between 13.78 and 63.1 μg/L in winter and summer respectively. The occurrence of THMs followed the given order: CHClBr2 (36%) > CHCl2Br (27%) > CHCl3 (25%) > CHBr3 (12%). The annual levels of THMs concentrations in the distribution networks of Baghdad City ranged between 12 and 97.3 μg/L in winter and summer, respectively, and followed the given order: CHClBr2 (37%) > CHCl2Br (33%) > CHCl3 (21%) > CHBr3 (9%). The World Health Organization (WHO) index for additive toxicity approach was in compliant with the WHO guideline value, and does not pose any adverse toxic health impacts. The hazard index does not suggest any potential noncancer risk to the exposed population, whereas the total multi-pathway cancer risk analysis suggests that total cancer risk exceeds the USEPA acceptable level of 10–6. 相似文献
3.
Rehan Sadiq Solomon Tesfamariam 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(4):495-505
Environmental indices (EI) constitute a common communication tool that is often used to describe the overall status of environmental
systems (air, water and soil). EI development entails the use of mathematical operators to aggregate various non-commensurate
input parameters in a logical manner. The ordered weighted averaging (OWA) operator is a general mean type operator that provides
flexibility in the aggregation process such that the aggregated value is bounded between minimum and maximum values of the
input parameters. This flexibility of the OWA operator is realized through the concept of orness, which is a surrogate for
decision maker’s attitude. The type of input parameters also affects the choice of aggregation operators. If the input parameters
are linguistic or fuzzy, the aggregation through OWA operators is not possible, and the use of fuzzy arithmetic is warranted.
The concept of fuzzy number OWA (FN-OWA) operators is explored to handle situations in which one or more input parameter has
fuzzy (or linguistic) values. The proposed approach is demonstrated using data provided in an earlier study by Swamee and
Tyagi (ASCE J Environ Eng 126(5):451–455, 2000) for establishing water quality indices. Multiple hypothetical scenarios are also generated to highlight the utility and
sensitivity of the proposed approach. 相似文献
4.
An integrated fuzzy simulation-assessment method (FSAM) was developed for assessing environmental risks from petroleum hydrocarbon contamination in ground water. In the FSAM, techniques of fuzzy simulation and fuzzy risk assessment were coupled into a general framework to reflect a variety of system uncertainties. A petroleum-contaminated site located in western Canada was selected as a study case for demonstrating applicability of the proposed method. The risk assessment results demonstrated that system uncertainties would significantly impact expressions of risk-level outputs. A relatively deterministic expression of the risks would have clearer representations of the study problem but may miss valuable uncertain information; conversely, an assessment under vaguer system conditions would help reveal potential consequences of adverse effects but would suffer from a higher degree of fuzziness in presenting the modeling outputs. Based on the risk assessment results, a decision analysis procedure was used to calculate a general risk index (GRI) to help identify proper responsive actions. The proposed method was useful for evaluating risks within a system containing multiple factors with complicated uncertainties and interactions and providing support for identifying proper site management strategies. 相似文献
5.
Water chlorination continues to be one of the most common water disinfection processes, especially in developing countries. When natural organic matter (NOM) is present, the process produces disinfection by-products (DBPs), some of them being trihalomethanes (THMs). This study determined the presence, speciation, and kinetics of THMs formation in the water supply for the northern area of the city of Toluca, Mexico. The results show that the concentrations of THMs are below the maximum allowable limits of 200 μg/L in accordance with NOM-127-SSA1-1994. Regarding THMs speciation, the presence of chloroform was more frequently observed in domestic water; furthermore, in one sample in which bromoform was present, it dominated over the chlorine species. Regarding the kinetics of THMs formation, a maximum concentration of THMs (THMsMax ) of 13.02 μg/L was obtained, and the time required to reach 50% THMsMax ( t 50 ) was 39.45 min. 相似文献
6.
Methodologies are presented for minimization of risk in a river water quality management problem. A risk minimization model is developed to minimize the risk of low water quality along a river in the face of conflict among various stake holders. The model consists of three parts: a water quality simulation model, a risk evaluation model with uncertainty analysis and an optimization model. Sensitivity analysis, First Order Reliability Analysis (FORA) and Monte–Carlo simulations are performed to evaluate the fuzzy risk of low water quality. Fuzzy multiobjective programming is used to formulate the multiobjective model. Probabilistic Global Search Laussane (PGSL), a global search algorithm developed recently, is used for solving the resulting non-linear optimization problem. The algorithm is based on the assumption that better sets of points are more likely to be found in the neighborhood of good sets of points, therefore intensifying the search in the regions that contain good solutions. Another model is developed for risk minimization, which deals with only the moments of the generated probability density functions of the water quality indicators. Suitable skewness values of water quality indicators, which lead to low fuzzy risk are identified. Results of the models are compared with the results of a deterministic fuzzy waste load allocation model (FWLAM), when methodologies are applied to the case study of Tunga–Bhadra river system in southern India, with a steady state BOD–DO model. The fractional removal levels resulting from the risk minimization model are slightly higher, but result in a significant reduction in risk of low water quality. 相似文献
7.
遥感影像土地覆盖分类面临"类别密度差异显著"、"同谱异物"和"同物异谱"等不确定性问题,传统的分类方法(如FCM)因不能描述高阶模糊不确定性,无法完成准确建模,使分类误差较大,而二型模糊集恰是处理此类不确定性的有效工具.在引入二型模糊集新概念和自适应降型新方法的基础上,提出一种自适应二型模糊分类方法(A-IT2FCM):(1)基于样本集模糊距离度量构建面向分类的区间二型模糊集,以尽可能降低对先验知识和预设参数的依赖,从而满足自动分类的要求;(2)给出一种自适应探求等价一型代表(模糊)集合的高效降型方法,在此基础上进行自适应区间二型模糊聚类.实验数据为珠海横琴和北京颐和园的SPOT5影像数据,对比方法有AIT2FCM、基于Karnik-Mendel算法降型和基于Tizhoosh提出的简易降型方法的区间二型模糊C均值聚类以及作者前期研究提出的区间值模糊C-均值算法(IV-FCM).实验结果表明,A-IT2FCM方法分类效果佳,在类别具有较大密度差异和多重模糊性时能得到比FCM及IV-FCM更精确的边界和更连贯的类别,适于处理遥感影像土地覆盖类别的深层不确定性;同时在"光谱混叠"现象严重时,可以获得比对比方法更稳健、精度更高的影像自动分类结果,且时间复杂度明显低于基于Karnik-Mendel方法. 相似文献
8.
An optimized analysis method based on headspace liquid phase microextraction (HS‐LPME) and gas chromatography coupled with mass spectrometry was proposed for the determination of trihalomethanes (THMs) in drinking water. The response surface method (RSM) was used to optimize the extraction of THMs for analysis by HS‐LPME. The temperature, extraction time and NaCl concentration were found to be important extraction parameters. The coefficient of determination (R2) for the model was 94.97%. A high probability value (P < 0.0001) for the regression indicated that the model had a high level of significance. The optimum conditions were seen to be: temperature 42.0°C, NaCl concentration 0.30 g/mL, and extraction time 28 min. The response variable was the summation of the THMs chromatography peak areas and the reproducibility of this was investigated in five replicate experiments under the optimized conditions. The relative standard deviations (RSD%) of the THMs ranged from 8.0–11.6%. The limits of detection (LODs), based on a signal‐to‐noise ratio (S/N) of three ranged from 0.42–0.78 μg/L, and were lower than the maximum limits for THMs in drinking water established by the WHO. 相似文献
9.
Probabilistic-fuzzy health risk modeling 总被引：3，自引：2，他引：1
Health risk analysis of multi-pathway exposure to contaminated water involves the use of mechanistic models that include many uncertain and highly variable parameters. Currently, the uncertainties in these models are treated using statistical approaches. However, not all uncertainties in data or model parameters are due to randomness. Other sources of imprecision that may lead to uncertainty include scarce or incomplete data, measurement error, data obtained from expert judgment, or subjective interpretation of available information. These kinds of uncertainties and also the non-random uncertainty cannot be treated solely by statistical methods. In this paper we propose the use of fuzzy set theory together with probability theory to incorporate uncertainties into the health risk analysis. We identify this approach as probabilistic-fuzzy risk assessment (PFRA). Based on the form of available information, fuzzy set theory, probability theory, or a combination of both can be used to incorporate parameter uncertainty and variability into mechanistic risk assessment models. In this study, tap water concentration is used as the source of contamination in the human exposure model. Ingestion, inhalation and dermal contact are considered as multiple exposure pathways. The tap water concentration of the contaminant and cancer potency factors for ingestion, inhalation and dermal contact are treated as fuzzy variables while the remaining model parameters are treated using probability density functions. Combined utilization of fuzzy and random variables produces membership functions of risk to individuals at different fractiles of risk as well as probability distributions of risk for various alpha-cut levels of the membership function. The proposed method provides a robust approach in evaluating human health risk to exposure when there is both uncertainty and variability in model parameters. PFRA allows utilization of certain types of information which have not been used directly in existing risk assessment methods. 相似文献
10.
Cengiz Kahraman İhsan Kaya 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(4):451-462
Water covers over 70% of the Earth surface and is a very important resource to people and the environment. Water pollution affects drinking water, rivers, lakes and oceans all over the world. This consequently harms human health and the natural environment. Water pollution can also affect the crops. So, water pollution is an important issue for humanity. Therefore, the control of irrigation water is a necessity. In this paper, a methodology based on process capability indices (PCIs) has been presented to control the levels of pH, dissolved oxygen (DO) and temperature (T) in dam’s water for irrigation. Fuzzy PCIs have been proposed for this aim. The fuzzy estimates of $ \hat C_p Water covers over 70% of the Earth surface and is a very important resource to people and the environment. Water pollution
affects drinking water, rivers, lakes and oceans all over the world. This consequently harms human health and the natural
environment. Water pollution can also affect the crops. So, water pollution is an important issue for humanity. Therefore,
the control of irrigation water is a necessity. In this paper, a methodology based on process capability indices (PCIs) has
been presented to control the levels of pH, dissolved oxygen (DO) and temperature (T) in dam’s water for irrigation. Fuzzy PCIs have been proposed for this aim. The fuzzy estimates of and are obtained for pH, DO, and T based on Buckley’s interval estimation approach and based on fuzzy specification limits. An application has been made for
Kesikk?prü Dam in Ankara, Turkey. In this paper, Buckley’s approach is re-arranged to obtain a triangular fuzzy membership
function because it cannot be obtained from Buckley’s approach in some situation. 相似文献
11.
Land cover classification of remote sensing imagery based on interval-valued data fuzzy c-means algorithm 总被引：1，自引：0，他引：1
There is a certain degree of ambiguity associated with remote sensing as a means of performing earth observations.Using interval-valued data to describe clustering prototype features may be more suitable for handling the fuzzy nature of remote sensing data,which is caused by the uncertainty and heterogeneity in the surface spectral reflectance of ground objects.After constructing a multi-spectral interval-valued model of source data and defining a distance measure to achieve the maximum dissimilarity between intervals,an interval-valued fuzzy c-means(FCM)clustering algorithm that considers both the functional characteristics of fuzzy clustering algorithms and the interregional features of ground object spectral reflectance was applied in this study.Such a process can significantly improve the clustering effect;specifically,the process can reduce the synonym spectrum phenomenon and the misclassification caused by the overlap of spectral features between classes of clustering results.Clustering analysis experiments aimed at land cover classification using remote sensing imagery from the SPOT-5 satellite sensor for the Pearl River Delta region,China,and the TM sensor for Yushu,Qinghai,China,were conducted,as well as experiments involving the conventional FCM algorithm,the results of which were used for comparative analysis.Next,a supervised classification method was used to validate the clustering results.The final results indicate that the proposed interval-valued FCM clustering is more effective than the conventional FCM clustering method for land cover classification using multi-spectral remote sensing imagery. 相似文献
12.
This study introduces a method using a multi-goal fuzzy cognitive map (FCM) and multi-criteria decision making based on sensitivity analysis to assess the risks associated with working accidents in underground collieries. Safety, stoppage in operation, and operational and capital costs are considered as the main goals during the FCM process with significant emphasis on safety. Workplace accidents data from Kerman underground collieries are statistically evaluated to find the degrees of occurrence probability, severity, and work-disability duration as the main risk factors. The causes and effects of accidents are analyzed using FCM based on three goals and the effects of risk factors. A sensitivity analysis on the weights of the goals is conducted with the aim of increasing the workplace safety in TOPSIS environment after solving the designed multi-goal FCM. Results indicate that “gas poisoning,” “roof fall,” and “debris and destruction” take the first three ranks and impose high risks to the system. By contrast, “collision, hit, and crash” presents the lowest risk among all accidents. 相似文献
13.
A fuzzy parameterized probabilistic analysis (FPPA) method was developed in this study to assess risks associated with environmental
pollution-control problems. FPPA integrated environmental transport modeling, fuzzy transformation, probabilistic risk assessment,
fuzzy risk quantification into a general risk assessment framework, and was capable of handling uncertainties expressed as
fuzzy-parameterized stochastic distributions. The proposed method was applied to two environmental pollution problems, with
one being about the point-source pollution in a river system with uncertain water quality parameters and the other being concerned
with groundwater contaminant plume from waste landfill site with poorly known contaminant physical properties. The study results
indicated that the complex uncertain features had significant impacts on modeling and risk-assessment outputs; the degree
of impacts of modeling parameters were highly dependent on the level of imprecision of these parameters. The results also
implied that FPPA was capable of addressing vagueness or imprecision associated with probabilistic risk evaluation, and help
generate risk outputs that could be elucidated under different possibilistic levels. The proposed method could be used by
environmental managers to evaluate trade-offs involving risks and costs, as well as identify management solutions that sufficiently
hedge against dual uncertainties. 相似文献
14.
Water resources systems are associated with a variety of complexities and uncertainties due to socio-economic and hydro-environmental impacts. Such complexities and uncertainties lead to challenges in evaluating the water resources management alternatives and the associated risks. In this study, the factorial analysis and fuzzy random value-at-risk are incorporated into a two-stage stochastic programming framework, leading to a factorial-based two-stage programming with fuzzy random value-at-risk (FTSPF). The proposed FTSPF approach aims to reveal the impacts of uncertainty parameters on water resources management strategies and the corresponding risks. In detail, fuzzy random value-at-risk is to reflect the potential risk about financial cost under dual uncertainties, while a multi-level factorial design approach is used to reveal the interaction between feasibility degrees and risk levels, as well as the relationships (including curvilinear relationship) between these factors and the responses. The application of water resources system planning makes it possible to balance the satisfaction of system benefit, the risk levels of penalty and the feasibility degrees of constraints. The results indicate that decision makers would pay more attention to the tradeoffs between the system benefit and feasibility degree, and the water allocation for agricultural section contributes most to control the financial loss of water. Moreover, FTSPF can generate a higher system benefit and more alternatives under various risk levels. Therefore, FTSPF could provide more useful information for enabling water managers to identify desired policies with maximized system benefit under different system-feasibility degrees and risk levels. 相似文献
15.
Emergency management evaluation by a fuzzy multi-criteria group decision support system 总被引：3，自引：1，他引：2
Guangquan Zhang Jun Ma Jie Lu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(4):517-527
Emergency risk management (ERM) is a process which involves dealing with risks to the community arising from emergency events.
Emergency management evaluation as one of the important parts of ERM aims assessing and improving social preparedness and
organizational ability in identifying, analyzing, and treating emergency risks. This study first develops an emergency management
evaluation model. It then proposes an extended fuzzy multi-criteria group evaluation method, which can deal with both subjective
and objective criteria under multi-levels by a group of evaluators, for emergency management evaluation. A fuzzy multi-criteria
group decision support system (FMCGDSS) is then developed to implement the proposed method for the case of emergency operating
center/system evaluation. 相似文献
16.
Elimination of Swimming Pool Water Disinfection By‐products with Advanced Oxidation Processes (AOPs)
Ozonation is a treatment step which was first applied in the 1960s in pool water treatment for disinfection as well as for oxidation of pool water contaminants. Contact time between ozone and pool water was identified to be of significance with an increased elimination efficiency regarding chloramines, trihalogenmethane formation potential and the permanganate index for longer reaction times. Oxidation via OH radicals might be the dominating pathway. In this study ozonation was compared with the ozone based advanced oxidation processes ozone/UV and ozone/hydrogen peroxide regarding the elimination efficiency of both disinfection by‐products (DBPs) and DBP precursors. It was observed that AOPs in comparison to ozonation showed an increased elimination efficiency regarding total organic carbon (TOC), the organically bound halogens adsorbable on activated carbon (AOX) and AOX formation potential. A contact time of 3 minutes between pool water and oxidant turned out to be practically sufficient. Just for the trihalomethane (THM) formation potential ozonation showed a slight advantage compared to the AOPs because ozonation is a highly selective oxidant and OH radical reactions are known to produce small reactive molecules which are easier transformed to THMs. Combination of membrane filtration and AOPs resulted in an elimination of 10 to 90 % of the DBPs and their precursors. The ozone/hydrogen peroxide process is suggested for pool water treatment because of the higher elimination rates compared to ozonation and of economic reasons compared to the ozone/UV process. 相似文献
17.
A new methodology for water resources multicriteria decision making under uncertainty 总被引：1，自引：0，他引：1
A multiciteria decision making problem in water resource is addressed through the generation of fuzzy Pareto optimal set. Methodology is using positive and negative ideal solutions (Lai, Y.-J., Liu, T.-Y., Hwang, C.L. (1994). TOPSIS for MODM. European Journal of Operational Research 76, 486-500) and a set of weights assigned to the objective functions in fuzzy triangular form. Solution of the problem is obtained by transforming each objective function into a set of three objective functions. A planning problem of multicriteria waste water treatment from the literature is used as an illustrative example to demonstrate the utility of the proposed methodology. The obtained fuzzy Pareto solution set has been compared with the deterministic solution set. It is shown that the proposed approach can: (a) capture the uncertainty associated with the assignment of weights; and (b) provide the decision makers with a wider range of solutions to select from. 相似文献
18.
19.
D. Z. Fu Y. P. Li G. H. Huang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2012,26(3):375-391
In this study, a fuzzy-Markov-chain-based stochastic dynamic programming (FM-SDP) method is developed for tackling uncertainties
expressed as fuzzy sets and distributions with fuzzy probability (DFPs) in reservoir operation. The concept of DFPs used in
Markov chain is presented as an extended form for expressing uncertainties including both stochastic and fuzzy characteristics.
A fuzzy dominance index analysis approach is proposed for solving multiple fuzzy sets and DPFs in the proposed FM-SDP model.
Solutions under a set of α-cut levels and fuzzy dominance indices can be generated by solving a series of deterministic submodels.
The developed method is applied to a case study of a reservoir operation system. Solutions from FM-SDP provide a range of
desired water-release policies under various system conditions for reservoir operation decision makers, reflecting dynamic
and dual uncertain features of water availability simultaneously. The results indicate that the FM-SDP method could be applicable
to practical problems for decision makers to obtain insight regarding the tradeoffs between economic and system reliability
criteria. Willingness to obtain a lower benefit may guarantee meeting system-constraint demands; conversely, a desire to acquire
a higher benefit could run into a higher risk of violating system constraints. 相似文献
20.
Elcin Kentel Mustafa M. Aral 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(4):405-417
In risk assessment studies it is important to determine how uncertain and imprecise knowledge should be included into the
simulation and assessment models. Thus, proper evaluation of uncertainties has become a major concern in environmental and
health risk assessment studies. Previously, researchers have used probability theory, more commonly Monte Carlo analysis,
to incorporate uncertainty analysis in health risk assessment studies. However, in conducting probabilistic health risk assessment,
risk analyst often suffers from lack of data or the presence of imperfect or incomplete knowledge about the process modeled
and also the process parameters. Fuzzy set theory is a tool that has been used in propagating imperfect and incomplete information
in health risk assessment studies. Such analysis result in fuzzy risks which are associated with membership functions. Since
possibilistic health risk assessment studies are relatively new, standard procedures for decision-making about the acceptability
of the resulting fuzzy risk with respect to a crisp standard set by the regulatory agency are not fully established. In this
paper, we are providing a review of several available approaches which may be used in decision-making. These approaches involve
defuzzification techniques, the possibility and the necessity measures. In this study, we also propose a new measure, the
risk tolerance measure, which can be used in decision making. The risk tolerance measure provides an effective metric for evaluating the acceptability
of a fuzzy risk with respect to a crisp compliance criterion. Fuzzy risks with different membership functions are evaluated
with respect to a crisp compliance criterion by using the possibility, the necessity, and the risk tolerance measures and
the results are discussed comparatively. 相似文献