Tolga Kaya

Fuzzy multicriteria disposal method and site selection for municipal solid waste.

The use of fuzzy multiple criteria analysis (MCA) in solid waste management has the advantage of rendering subjective and implicit decision making more objective and analytical, with its ability to accommodate both quantitative and qualitative data. In this paper a modified fuzzy TOPSIS methodology is proposed for the selection of appropriate disposal method and site for municipal solid waste (MSW). Our method is superior to existing methods since it has capability of representing vague qualitative data and presenting all possible results with different degrees of membership. In the first stage of the proposed methodology, a set of criteria of cost, reliability, feasibility, pollution and emission levels, waste and energy recovery is optimized to determine the best MSW disposal method. Landfilling, composting, conventional incineration, and refuse-derived fuel (RDF) combustion are the alternatives considered. The weights of the selection criteria are determined by fuzzy pairwise comparison matrices of Analytic Hierarchy Process (AHP). It is found that RDF combustion is the best disposal method alternative for Istanbul. In the second stage, the same methodology is used to determine the optimum RDF combustion plant location using adjacent land use, climate, road access and cost as the criteria. The results of this study illustrate the importance of the weights on the various factors in deciding the optimized location, with the best site located in Catalca. A sensitivity analysis is also conducted to monitor how sensitive our model is to changes in the various criteria weights.

An integrated fuzzy AHP-ELECTRE methodology for environmental impact assessment

Environmental impact assessment (EIA) is the assessment of the possible impact that a proposed plan or project may have on the environment, together consisting of the natural, social and economic aspects. The aim of this paper is to propose an environmental impact assessment methodology based on an integrated fuzzy AHP-ELECTRE approach in the context of urban industrial planning. In the proposed methodology the criteria weights are generated by a fuzzy AHP procedure. The fuzzy set theory is a perfect means for modeling uncertainty or imprecision arising from human mental phenomena. The usage of fuzzy sets in describing uncertainties and vagueness in different environmental factors simplifies the complex structure of EIA. A fuzzy outranking methodology, fuzzy ELECTRE is used to assess the environmental impact generated by the six different industrial districts which were predicted to shape the future industrial structure of Istanbul metropolitan area. Finally, a fuzzy dominance relation (FDR) methodology is used to rank the alternatives from the most risky to the least. A sensitivity analysis is also provided.

Fuzzy multiple criteria forestry decision making based on an integrated VIKOR and AHP approach

Research highlights? An integrated fuzzy VIKOR-AHP methodology is suggested. ? The weights of the selection criteria are determined by fuzzy AHP. ? The methodology is applied to a forestation district selection problem. Forestation and forest preservation in urban watersheds are issues of vital importance as forested watersheds not only preserve the water supplies of a city but also contribute to soil erosion prevention. The use of fuzzy multiple criteria decision aid (MCDA) in urban forestation has the advantage of rendering subjective and implicit decision making more objective and transparent. An additional merit of fuzzy MCDA is its ability to accommodate quantitative and qualitative data. In this paper an integrated VIKOR-AHP methodology is proposed to make a selection among the alternative forestation areas in Istanbul. In the proposed methodology, the weights of the selection criteria are determined by fuzzy pairwise comparison matrices of AHP. It is found that Omerli watershed is the most appropriate forestation district in Istanbul.

A fuzzy approach to e-banking website quality assessment based on an integrated AHP-ELECTRE method

Abstract Given the lack of physical constraints of retail banking; attraction, satisfaction, and retention of customers in e-banking mostly depend on the quality of service delivered by the website. Hence, effective assessment and monitoring of website quality have become prerequisites for profitable e-banking. Determining the overall quality of a banking website is a multidimensional issue that involves evaluation of information system (IS) quality, customer services quality, and product quality. The purpose of this study is to propose an e-banking website quality assessment methodology based on an integrated fuzzy AHP-ELECTRE approach. The fuzzy set theory has been developed for dealing with the problems arising from the vagueness, ambiguity, and subjectivity of human judgment. In the proposed methodology, the weights of the criteria are generated by a fuzzy AHP analysis. Next, fuzzy ELECTRE is used to assess the quality levels of the websites. In the third step, a fuzzy dominance relation approach is u...

Multi-attribute Evaluation of Website Quality in E-business Using an Integrated Fuzzy AHPTOPSIS Methodology

Success of an e-business company is strongly associated with the relative quality of its website compared to that of its competitors. The purpose of this study is to propose a multi-attribute e-business website quality evaluation methodology based on a modified fuzzy TOPSIS approach. In the proposed methodology, weights of the evaluation criteria are generated by a fuzzy AHP procedure. In performance evaluation problems, the judgments of the experts may usually be vague in form. As fuzzy logic can successfully deal with this kind of uncertainty in human preferences, both classical TOPSIS and classical AHP procedures are implemented under fuzzy environment. The proposed TOPSIS-AHP methodology has successfully been applied to a multi-attribute website quality evaluation problem in Turkish e-business market. Nine sub-criteria under four main categories are used in the evaluation of the most popular e-business websites of Turkey. A sensitivity analysis is also provided.

A New Batteryless Active RFID System: Smart RFID

Since RFID systems start to share the supply chain market with the barcodes, new application areas have become attractive where the wireless radio-frequency communication and identification is possible. Unlike the passive systems, active RFID systems can be used as sensor nodes and they can monitor and store environment data, such as acceleration or temperature. However, the need of external battery limits their applications to where battery replacements are only possible. In this paper, a new batteryless active RFID transponder system has been proposed based on a MEMS (Micro-Electro Mechanical Systems) energy scavenger. The mechanical part of the system has been designed and fabricated. The circuit level simulations have been performed. In this context, a new modulation scheme has been proposed and a magnetic random access memory (MRAM) has been used for the data storage.

Facility Location Selection in Reverse Logistics Using a Type-2 Fuzzy Decision Aid Method

Location selection for the process of moving goods from their final destination to ensure proper value creation is a multi-faceted issue which requires consideration of social, economic, environmental and technical factors. The fuzzy sets theory is a good tool for dealing with complex and subjective problems which make use of implicit human judgments. Type-2 fuzzy sets provide more degrees of freedom to reflect the uncertainty and the ambiguity of real cases. The aim of this study is to suggest a multi criteria approach for the selection of the most appropriate reverse logistics facility location using a type-2 fuzzy TOPSIS methodology. Using proposed methodology, a case study from an e-waste recycling industry is conducted. In the evaluations, criteria like social acceptability, environmental risks, biodiversity conservation, operation and investment costs, energy and transportation infrastructure, legal/political environment, and growth potentials of the region are considered.

A modified active current mirror suitable for current-mode algorithmic analog-to-digital converters

A modified active current mirror suitable for precision current-mode algorithmic analog-to-digital converters is presented. Employing only a 5-transistor opamp, with aid of a novel method, the current mirror achieves high current transfer accuracy for a wide range of input current level. Comparison with a conventional active current mirror and first results associated with ADC implementation are also supplied, via spectreS simulations.

Regional employment generation potential of the Turkish labor market: an inter-sectoral perspective

AbstractContractionary effects of the current global crisis are not homogenous among sectors. Moreover, sectoral employment multipliers and high regional unemployment differentials unequally transfer these effects into labor market. The purpose of this study is to explore the inter-sectoral sensitivities of regional labor markets in Turkey to changes in the final demand. To do this, we decompose the labor demand by sectors and by regions using input-output methodology. Own employment generation effects and regional employment multipliers of each sector are calculated. Overall findings constitute an employment generation map of Turkey. One of the major findings is the strength of the mutual relationship between agriculture and manufacturing sectors. The biggest spillover effect is created by manufacturing upon mostly agriculture, trade and transportation. Agriculture, social services and trade are the most sensitive sectors to changes in the final demand. At regional level; trade, social services and manuf...

Promoting investment in the Turkish construction sector: a structural path analysis

ABSTRACT The construction sector in Turkey boomed in the period between the turn of the millennium and the onset of the global crisis. This paper studies the employment generation effects of growth of this sector, taking into account that it not only depends on domestic production factors but also on imported inputs. In order to unravel the interactions of the construction sector with the rest of the economy, structural path analysis of both labour and imported intermediate input demand generation is used based on the 2002 and 2009 WIOD data for Turkey. The findings indicate that labour linkages weakened between 2002 and 2009, while import linkages became slightly stronger. The sectors that have played key roles in this are identified, as are the linkages between these. The findings have implications for the persistent unemployment and current account deficits in Turkey.