Journal of Intelligent & Fuzzy Systems - Volume 27, issue 6

Authors: Büyüközkan, Gülçin | Güleryüz, Sezin

Article Type: Research Article

Abstract: Renewable energy resources (RER) are one of the most growing energy sources in the world and various researches point out that these resources will have vital importance in the future. On the other hand, limited reserves and negative environmental impacts of fossil fuels make investors to consider RER for their needs in a sustainable way. To select most appropriate RER alternatives, it is essential to prioritize alternatives which provide minimum negative environmental impact caused by RER operations and maximum financial benefits to the investor. This study aims to develop a novel RER evaluation model that can help investors with their …critical selection process and identify the priority of RER alternatives. High complexity of socioeconomic environments often makes it difficult for a single decision maker (DM), investor in our case, to consider all important aspects of selection problems. Therefore, group decision making (GDM) is often preferred to avoid the bias and minimize the partiality in this kind of decision process. In some critical situations DMs' judgments can be under uncertainty where it is difficult for them to provide exact numerical values. In these cases, linguistic interval fuzzy preference relations are utilized to better represent DMs' preferences. This paper develops a new GDM approach based on fuzzy analytic hierarchy process (AHP) with linguistic interval fuzzy preference relations for obtaining weights of selected evaluation criteria. Then, the fuzzy technique for order performance by similarity to ideal solution (TOPSIS) approach is applied for ranking suitable RER alternatives. The originality of the paper comes from the application of these combined methodologies in literature for the first time and no previous work has investigated this RER subject using this kind of an integrated method. For demonstrating the potential of the proposed approach, a motivated example is given to select the most suitable RER for Turkey. Show more

Keywords: Renewable energy resources, MCDM, group decision making, AHP, Linguistic interval fuzzy references, fuzzy TOPSIS

DOI: 10.3233/IFS-141275

Citation: Journal of Intelligent & Fuzzy Systems, vol. 27, no. 6, pp. 3181-3195, 2014

Authors: Siahi, Mehdi | Rahatabad, Fereidoun Nowshiravan | Khayat, Omid | Razjouyan, Javad | Nejad, Hadi Chahkandi

Article Type: Research Article

Abstract: In this paper largest Lyapunov exponent and low frequency power ratio of the Center-of-Pressure (COP) signal are calculated and considered as two discriminative features to characterize prolonged standing and its effect on postural control in elderly individuals in comparison to adults. It is unknown how elderly individuals behave during standing and how demanding such a task is for them. We recorded the center of pressure position of 16 elder subjects and 24 young subjects while they performed standing (30 second). Statistical and frequency-based features are extracted and an analysis is performed to find the most appropriate and discriminative features for …elder and young subjects posture signals discrimination. Standard deviation and mean value as statistical parameters, low frequency power ratio as frequency based feature and largest Lyapunov exponent (LLE) of COP signal as the chaotic feature are computed to discriminate the COP signals of young and old subjects. LLE is estimated to show the impact of chaotic behavior in static balance relative to the age. Implementations on the normal subjects demonstrate that working in frequency and chaotic domains is preferred to time domain and statistical analysis and largest Lyapunov exponent of the posture signal can be representatively used for COP signal characterization. Show more

Keywords: Static balance, center of pressure signal, age-related analysis, largest lyapunov exponent, standard deviation, low frequency power ratio

DOI: 10.3233/IFS-141276

Citation: Journal of Intelligent & Fuzzy Systems, vol. 27, no. 6, pp. 3197-3204, 2014

Authors: Manjusha, O.T. | Sunitha, M.S.

Article Type: Research Article

Abstract: In this paper different types of degrees of a node in fuzzy graphs are discussed. The domination number of $K_{\sigma_{1},\sigma_{2}}$ as given in the paper “Domination in fuzzy graphs-I” by A. Somasundaram and S. Somasundaram is modified. A lower bound and an upper bound for the domination number of fuzzy graphs are obtained. Domination in fuzzy trees is studied. It is established that the set of fuzzy cut nodes of a fuzzy tree is a dominating set and obtained a necessary and sufficient condition for the set of fuzzy end nodes to be a dominating set. Also it …is proved that in a fuzzy tree each node of a dominating set is incident on a fuzzy bridge. Show more

Keywords: Fuzzy graph, strong arcs, domination number

DOI: 10.3233/IFS-141277

Citation: Journal of Intelligent & Fuzzy Systems, vol. 27, no. 6, pp. 3205-3212, 2014

Authors: Gnana King, G.R. | Seldev Christopher, C.

Article Type: Research Article

Abstract: Compression and transmission of compound images are essential processes in real time applications where there is a necessity that the compression technique should attain high compression ratio, low complexity, high PSNR value and a required level of security. This paper proposes a novel method for block-based compound image compression. The pictorial blocks and text/graphics blocks are separated from the compound image. The pictorial blocks are compressed using discrete Haar wavelet transformation and text/graphics colors are mapped to primary colors using color quantization algorithm and the resulting index values are then compressed using the lossless Huffman coding technique. The compressed image …is then encrypted using an Advanced Encryption Standard algorithm which ensures that the transmission is fast and highly secured. Experimental results conclude that the proposed algorithm provides better results like low complexity, high compression ratio and a high PSNR value than most of the other image compression techniques. Show more

Keywords: Compound image compression, haar wavelet transformation, huffman coding and advanced encryption standard algorithm

DOI: 10.3233/IFS-141278

Citation: Journal of Intelligent & Fuzzy Systems, vol. 27, no. 6, pp. 3213-3225, 2014

Article Type: Other

Citation: Journal of Intelligent & Fuzzy Systems, vol. 27, no. 6, pp. 3227-3240, 2014