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        검색결과 13

        1.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fast service access involves keeping track of the location of mobile users, while they are moving around the mobile network for a satisfactory level of QoS (Quality of Service) in a cost-effective manner. The location databases are used to keep track of Mobile Terminals (MT) so that incoming calls can be directed to requested mobile terminals at all times. MT reporting cell system used in location management is to designate each cell in the network as a reporting cell or a non-reporting cell. Determination of an optimal number of reporting cells (or reporting cell configuration) for a given network is reporting cell planning (RCP) problem. This is a difficult combinatorial optimization problem which has an exponential complexity. We can see that a cell in a network is either a reporting cell or a non-reporting cell. Hence, for a given network with N cells, the number of possible solutions is  . We propose a biogeography based optimization (BBO) for design of mobile station location management system in wireless communication network. The number and locations of reporting cells should be determined to balance the registration for location update and paging operations for search the mobile stations to minimize the cost of system. Experimental results show that our proposed BBO is a fairly effective and competitive approach with respect to solution quality for optimally designing location management system because BBO is suitable for combinatorial optimization and multi-functional problems.
        4,000원
        2.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A wireless sensor network is emerging technology and intelligent wireless communication paradigm that is dynamically aware of its surrounding environment. It is also able to respond to it in order to achieve reliable and efficient communication. The dynamical cognition capability and environmental adaptability rely on organizing dynamical networks effectively. However, optimally clustering the cognitive wireless sensor networks is an NP-complete problem. The objective of this paper is to develop an optimal sensor network design for maximizing the performance. This proposed Ranking Artificial Bee Colony (RABC) is developed based on Artificial Bee Colony (ABC) with ranking strategy. The ranking strategy can make the much better solutions by combining the best solutions so far and add these solutions in the solution population when applying ABC. RABC is designed to adapt to topological changes to any network graph in a time. We can minimize the total energy dissipation of sensors to prolong the lifetime of a network to balance the energy consumption of all nodes with robust optimal solution. Simulation results show that the performance of our proposed RABC is better than those of previous methods (LEACH, LEACH-C, and etc.) in wireless sensor networks. Our proposed method is the best for the 100 node-network example when the Sink node is centrally located.
        4,000원
        3.
        2015.06 구독 인증기관·개인회원 무료
        The advancement of industry and science in modern society has facilitated the inherent growth of humanity due to the provisions of large amounts of information and knowledge. Deconstructionism originated from the desire for self-expression rooted in the inherent growth of humanity and desires to express various characteristics through deconstruction and not be classified and constrained by existing dichotomous structures and forms. Deconstructism (an idea to resist dichotomous ideas and existing structuralism) seeks androgyny as well as the deconstruction of sex vis-à-vis human desire. Human androgyny, inherent in history and ancient Greek myths (Kwon, 2002), is now being adapted by modern society, psychology, culture, and art (Han & Kim, 2012). Androgyny, adapted by literature, sculpture, and painting, is now being used by the production of various images as well as modern fashion costumes. It is necessary to study androgyny to provide an aesthetic value for modern fashion design that can also deeply analyze the ideas and philosophies of fashion designers. This study considers androgyny with a focus on deconstructive fashion, understanding the tendency of androgyny in modern fashion, and providing a reference material for future fashion designs as well as for the direction and development of various fashion accessories and hair accessories. This study uses internet resources and previous research from professional journals and books about deconstructionism and androgyny for a literature review. It adapts an empirical method based on visual images from the design collections of designers defined as deconstructive fashion designers by researchers and professional editors. The androgyny of deconstructive fashion is classified in this study as follows. The first are ambiguous designs that show no clear distinction between sexes. The designers show designs unconstrained by sexes and which seek human instinct through wearing fashion items of the opposite sex that use masks and express sexual ambiguity with makeup and costumes. The second is integration shown in designs with both masculine and feminine characteristics. The designers integrates the lines and details of the opposite sex with costumes and patterns to escape existing ideas and show a silhouette that eliminate sexual stereotypes. The third is deconstructivity as shown in designs with no sexual characteristic and no sexual concept. It is a trend that originated from the interpretative view that adapts the super realism of deconstructionism and is free from an existing aesthetic consciousness to deconstruct a sex role for existing costumes and refuse all standardized ideas; consequently, the roles of costumes and items are eliminated and a new fashion style emerges from the individual values and ideas of designers. The androgyny of modern fashion from deconstructionism diverges from traditional form, integrates with aesthetic factors, and becomes one of a modern style that also provides more creative design motifs for fashion designers.
        4.
        2014.04 구독 인증기관·개인회원 무료
        Urbanization is one of the leading causes of habitat loss, habitat degradation, and fragmentation. Urban development negatively affects biodiversity. This study aimed to clarify the change of butterfly communities on effect of urbanization in urban green areas. Butterfly survey was conducted using the line transect methods from April to October in 2012. A total of 59 species and 1,465 individuals of butterflies were observed in four urban green areas: Namsan Park (NS), Ewha Womans University (EW), Bukseoul Dream Forest (BD), and Hongneung Forest (HF), and natural forest: Gwangneung Forest (GF). The category of land use around study site was determined based on GIS data. Species richness and abundance of niche breadth and habitat type in urban green areas differed significantly from those in GF. Estimated species richness and species diversity (H’) in four urban green areas were significantly lower than those in GF. Species richness and abundance of forest interior species and specialist were positively correlated with paddy, field, and forest, whereas those of forest interior species and specialist were negatively correlated with urban area and road. Butterfly communities in four urban green area differed from that in GF. The result suggests that the decrease of paddy, field, and forest associated with increase of urban area and road negatively influences species composition and changes butterfly communities.
        5.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnetic and dielectric properties of rubber composites are controlled by using two kinds of high-permeability metal particles with different electrical conductivity (Sendust, Permalloy), and their effect on microwave absorbance has been investigated, focusing on the quasi-microwave frequency band (0.8-2 GHz). Noise absorbing sheets are composite materials of magnetic flake particles of high aspect ratio dispersed in polymer matrix with various filler amount of 80-90 wt.%. The frequency dispersion and magnitude of complex permeability is almost the same for Sendust and Permalloy composite specimens. However, the complex permittivity of the Permalloy composite (, ) is much greater than that of Sendust composite (, ). Due to the large dielectric permittivity of Permalloy composite, the absorbing band is shifted to lower frequency region. However, the investigation of impedance matching reveals that the magnetic permeability is still small to satisfy the zero-reflected condition at the quasi-microwave frequency band, resulting in a small microwave absorbance lower than 10 dB.
        3,000원
        6.
        2013.04 구독 인증기관·개인회원 무료
        The species status of Oeneis urda (Eversmann) and O. mongolica (Oberthür) has been argued based on morphological characters. Reexamination of their major morphological characters has shown a slight differentiation in the two species. Sequences of three mitochondrial genes (COI, ND6, and ND1) and one nuclear region (internal transcribed spacer 2, ITS2) from two O. urda populations (Yangyang and Mt. Hanla) and one O. mongolica population (Uljin) were performed for phylogenetic and population genetic inferences. Sharing of identical sequences in the ND6 gene and ITS2, minimal sequence divergence in the COI and ND1 genes, and phylogenetically undividable sequence types in all mitochondrial genes and ITS2 suggest genetic continuity between the two species. Nevertheless, significant FST estimates (p < 0.05) were found for the COI gene in comparisons between Yangyang (O. urda) and Uljin (O. mongolica), between Yangyang (O. urda) and Mt. Hanla (O. urda), and between Uljin (O. mongolica) and Mt. Hanla (O. urda) populations. These FST estimates, along with other gene-based analyses collectively suggest isolation of the two species at some point in the past, but incomplete separation between the two species on the mainland (Yangyang and Uljin) and biogeographically forced isolation of the O. urda population on Mt. Hanla collectively appear to complicate species status of these two species that were once further clearly separated.
        7.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the aim of low-temperature co-fired ceramic microwave components, sintering behavior and microwave properties (dielectric constant , quality factor Q, and temperature coefficient of resonant frequency ) are investigated in [BCZN] ceramics with addition of . The specimens are prepared by conventional ceramic processing technique. As the main result, it is demonstrated that the additives () show the effect of lowering of sintering temperature and improvement of microwave properties at the optimum additive content. The addition of 0.25 wt% lowers the sintering temperature to utilizing liquidphase sintering and show the microwave dielectric properties (dielectric constant = 75, quality factor = 572 GHz, temperature coefficient of resonance frequency ). The estimated microwave dielectric properties with addition (increase of , decrease of , shift of to negative values) can be explained by the observed microstrucure (sintered density, abnormal grain structure) and possibly high-permittivity (BZN) phase determined by X-ray diffraction.
        4,000원
        8.
        2010.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two kinds of oxide-dispersion-strengthened (ODS) 316L stainless steel were manufactured using a wet mixing process(wet) and a mechanical alloying method (MA). An MA 316L ODS was prepared by a mixing of metal powder and a mechanical alloying process. A wet 316L ODS was manufactured by a wet mixing with 316L stainless steel powder. A solution of yttrium nitrate was dried after being in the wet 316L ODS alloy. The results showed that carbon and oxygen were effectively reduced during the degassing process before the hydroisostatic process (HIP) in both alloys. It appeared that the effect of HIP treatment on increase in impact energy was pronounced in the MA 316L ODS alloy. The MA 316L ODS alloy showed a higher yield strength and a smaller elongation, when compared to the wet 316L ODS alloy. This seemed to be attributed to the enhancement of bonding between oxide and matrix particles from HIP and to the presence of a finer oxide of about 20 nm from the MA process in the MA 316L ODS alloy.
        4,000원
        9.
        2009.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Austenitic oxide-dispersion-strengthened (ODS) stainless steel was fabricated using a wet mixing process without a mechanical milling in order to reduce contaminations of impurities during their fabrication process. Solution of yttrium nitrate was dried after a wet mixing with 316L stainless steel powder. Carbon and oxygen contents were effectively reduced by this wet processing. Microstructural analysis showed that coarse yttrium silicates of about 150 nm were formed in austenitic ODS steels with a silicon content of about 0.8 wt%. Wet-processed austenitic ODS steel without silicon showed higher yield strength by the presence of finer oxide of about 20 nm.
        4,000원