• Title/Summary/Keyword: spatial diversity

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A Study on Estimates to Longevity Population of Small Area and Distribution Patterns using Vector based Dasymetric Mapping Method (벡터기반 대시매트릭 기법을 이용한 소지역 장수인구 추정 및 분포패턴에 관한 연구)

  • Choi, Don-Jeong;Kim, Young-Seup;Suh, Yong-Cheol
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.5
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    • pp.479-485
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    • 2011
  • A number of case studies that find distribution of longevity population and influencing factors through the spatial data fusion using GIS techniques are growing. The majority cases of these studies are adopt census administrative boundary data for the spatial analysis. However, these methods cannot fully explain the phenomenon of longevity because there are a variety of spatial characteristics within the census administrative boundaries. Therefore, studies of spatial unit are required that realistically reflect the phenomenon of human longevity. The dasymetric mapping method enables to product of spatial unit more realistic than census administrative boundary map and statistic estimates of small area utilizing diversity spatial information. In this study, elderly population of small area has been estimated within statistically significant level that applied the vector based dasymetric mapping method. Also, the cluster analysis confirmed that the variation of local spatial relationship within census administrative boundary. The result of this study implied that the need for local-level studies of the human longevity and the validity of the dashmetric mapping techniques.

Mitigation of Inter-Symbol Interference in Underwater Acoustic Communication Using Spatial Filter (공간 필터를 이용한 수중음향통신의 인접 심볼 간 간섭 완화)

  • Eom, Min-Jeong;Park, Ji-Sung;Ji, Yoon-Hee;Kim, J.S.
    • The Journal of the Acoustical Society of Korea
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    • v.33 no.1
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    • pp.48-53
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    • 2014
  • The underwater acoustic communication (UAC) is characterized by doubly spread channel. It is included in the time-variant doppler shift and delay-time spreads due to multiple paths. To compensate such distorted signals, various techniques including time-reversal processing, spatial diversity, phase estimator, and equalizer are being applied. In this paper, a spatial filter based on the beamforming is proposed as a method to mitigate such inter-symbol interferences that are generated in time-varying multipath channels. The proposed technique realizes coherent communications by steering the direction of the desired signals and improves the performance of UAC by increasing the signal-to-interference plus noise ratio using the array gain.

Performance of Space Time Block Coded-Spatial Multiplexing Systems in Limited Feedback Channel (제한된 귀환채널에서 시공간블록부호화를 적용한 다중화 시스템의 성능)

  • Hwang, Hyeon-Chyeol;Shin, Seung-Hoon;Lim, Jong-Kyoung;Kim, Seok-Ho;Kwak, Kyung-Sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.9A
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    • pp.772-780
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    • 2005
  • In this paper, an efficient pre-processing in space tine block coded-spatial multiplexing systems is presented. The pre-processing scheme is designed empirically with extending the diagonally weighted orthogonal space time-block coded diversity system to spatial multiplexing system. Simulation results show the proposed scheme outperforms both the precoder using the predefued codebooks and typical antenna selection scheme over moderate doppler frequency in limited feedback channel.

A Study on the Spatial Presentation Strategies for Cafe as 'The Third Space' - Focused on the cafes located in regions where 'Street culture' was formed - ('제3의 공간'으로서 카페의 공간연출 전략에 관한 연구 - '길(street) 문화'가 형성된 지역을 중심으로 -)

  • Moon, Geun-Yi;Lyu, Ho-Chang
    • Korean Institute of Interior Design Journal
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    • v.22 no.5
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    • pp.68-77
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    • 2013
  • 'The Third space,' which is the concept that embraces sociological, spatial, and marketing concepts, refers to the place which is other than the home and the workplace and which is a comfortable frequented place where meditation, psychological relaxation, and social needs can be satisfied. 'The Third space' has the characteristics of comfort, openness, interactivity, playfulness, and diversity. In modern times, most of consumption spaces play the role of 'the Third space,' and the typical example is $Caf{\acute{e}}$. $Caf{\acute{e}}$ began from its origin with the characteristics of 'the Third space,' and recently it has become the complex cultural space of urban dwellers. $Caf{\acute{e}}$ as 'the Third space' has the characteristics of a healing space, communication space, personalized space, value-expressive space, culture and consumption space, nomad space. Such characteristics of $Caf{\acute{e}}$ are well represented in the cafes around the regions where 'street culture' has recently been formed. As examined through the examples, $Caf{\acute{e}}$ as 'the Third space' can be more strategically produced by establishing themes through storytelling, giving spatial identity through style creation, diversifying the sequence through complex space organization, and establishing interaction devices through experience elements.

A Study on the Spatial Configuration Characteristics of the Apartment Building Type based on the Space Syntax Analysis (공간구문론 분석에 의한 아파트 주동형식별 공간배치 특성에 관한 연구)

  • 박몽섭;박찬돈;하재명
    • Journal of the Korean housing association
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    • v.15 no.1
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    • pp.185-194
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    • 2004
  • This paper deals with the spatial configuration of the unit floor plan based on the apartment building type. It is generally agreed that various apartment building types were organized by diverse apartment unit floor plan. The reason behind this diversity, apartment unit plan are affected by the environmental condition and the diverse spatial composition of the unit floor plan. Apartment building types were classified by the similarity of the justified-graph type. This types classified into two category; One core type which were classified by the shape of the core, and multiple core type which were compounded by more than two core. These categories divided into 5 types, and 2 types. Each types were compared in view of the mean depth, relative asymmetry, integration value. Consequently, these types could be classified in the number of the unit floor plan. It is profitable to 3 unit types which was analyzed in view of an indicator of the spatial configuration. Therefore, 3 unit types is favorable to the composition of the apartment building types.

Recent changes in the phytoplankton community of Soda Lake Chitu, Ethiopia, in response to some environmental factors

  • Demtew Etisa;Yiglet Mebrat
    • Fisheries and Aquatic Sciences
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    • v.27 no.1
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    • pp.23-34
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    • 2024
  • While scientific information on the spatial variation of soda lake Microalgae is important to limnological studies, little information was reported from the Ethiopian Rift Valley Lake, Lake Chitu. This study aimed to understand the spatial distribution of the dominant Microalgae taxa in Lake Chitu, Ethiopia. The collection of samples and in situ measurements of some physico-chemical parameters were recorded at three sites for one cycle in November 2021. Fourteen species or genera of Microalgae were identified. Among those, Bacillariophyta were the most important with regard to species abundance and the rarest in species richness. Cyanophyta were the second-most important group in terms of species richness and rarity. Comparatively, all microalgae taxa were rare at both the anthropogenic areas (AA) and the flooding area (FA), which could be mainly due to intensive human and animal intervention and associated with extreme turbidity. Among Cyanophyta, Chroococcus minutus, Microcystis aeruginosa, and Spirulina platensis/fusiformis were predominant at both AA and FA, revealing their adaptation to less clear water and pollution. But S. platensis/fusiformis attained the highest abundance at the FA, indicating their preference for water in a highly nutrient-enriched area. We concluded that the spatial variation of microalgae diversity in relation to water quality parameters has implications for the importance of microalgae as a baseline indicator of water quality assessment tools in lakes.

Genetic Structure and Composition of Genetic Diversity in the Kouchi Sub-breed of the Japanese Brown Cattle Population

  • Honda, Takeshi;Fujii, Toshihide;Mukai, Fumio
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.11
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    • pp.1631-1635
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    • 2007
  • Japanese Brown cattle, one of the four domestic beef breeds in Japan, are suffering from numerical reduction due to economic pressure from profitable breeds. In this study, all the reproductive cows in the Kouchi sub-breed of the Japanese Brown cattle that were alive in July 2005 were investigated by pedigree analysis to clarify genetic structure and composition of genetic variability. In addition, genetically important individuals for the maintenance of genetic variability of the sub-breed were also identified through the core set method. The number of cows analyzed was 1,349. Their pedigrees were traced back to ancestors born around 1940, and pedigree records of 13,157 animals were used for the analysis. Principal component analysis was performed on the relationship matrix of the cows, and their factor loadings were plotted on a three-dimensional diagram. According to their spatial positions in the diagram, all the cows were subdivided into five genetically distinctive subpopulations of 131 to 437 animals. Genetic diversity of the whole sub-breed, which is estimated to be 0.901, was decomposed into 0.856 and 0.045 of within-subpopulation and between-subpopulation components. Recalculation of genetic diversity after removal of one or several subpopulations from the five subpopulations suggested that three of them were genetically important for the maintenance of genetic variability of the sub-breed. Applying the core set method to all the cows, maximum attainable genetic diversity was estimated to be 0.949, and optimal genetic contributions assigned to each cow supported the previous results indicating relative importance of the three subpopulations as useful genetic materials.

Performance Analysis of 1-2-1 Cooperative Protocol in Wireless Sensor Networks (무선 센서 네트워크에서 1-2-1 협력 프로토콜에 관한 연구)

  • Choi, Dae-Kyu;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.8 no.5
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    • pp.113-119
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    • 2008
  • Conventional 1-1-1 cooperative protocol offers path-loss gain as advantage of multi-hop and spatial diversity which is equivalent to MIMO system. This protocol is enable to get higher reliability and reduction of power consumption than those of the single-hop or multi-hop. But the 1-1-1 cooperative protocol get only the diversity order 2 and limited path-loss reduction gain because this protocol has a single cooperative relay. We propose 1-2-1 cooperative protocol using two cooperative relays R1, R2. The 1-2-1 cooperative protocol can improve path-loss reduction and increase diversity order 3. Moreover, the cooperative relay R2 attains diversity order 2. The signaling method in transmission uses DF (Decode and Forward) or DR (Decode and Reencode) and 1-2-1 DF/DR cooperative protocol are applied to clustering based wireless sensor networks (WSNs). Simulations are performed to evaluate the performance of the protocols under Rayleigh fading channel plus AWGN (Additive White Gaussian Noise).

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Optimization for Relay-Assisted Broadband Power Line Communication Systems with QoS Requirements Under Time-varying Channel Conditions

  • Wu, Xiaolin;Zhu, Bin;Wang, Yang;Rong, Yue
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.10
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    • pp.4865-4886
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    • 2017
  • The user experience of practical indoor power line communication (PLC) applications is greatly affected by the system quality-of-service (QoS) criteria. With a general broadcast-and-multi-access (BMA) relay scheme, in this work we investigate the joint source and relay power optimization of the amplify-and-forward (AF) relay systems used under indoor broad-band PLC environments. To achieve both time diversity and spatial diversity from the relay-involved PLC channel, which is time-varying in nature, the source node has been configured to transmit an identical message twice in the first and second signalling phase, respectively. The QoS constrained power allocation problem is not convex, which makes the global optimal solution is computationally intractable. To solve this problem, an alternating optimization (AO) method has been adopted and decomposes this problem into three convex/quasi-convex sub-problems. Simulation results show the fast convergence and short delay of the proposed algorithm under realistic relay-involved PLC channels. Compared with the two-hop and broadcast-and-forward (BF) relay systems, the proposed general relay system meets the same QoS requirement with less network power assumption.

Niche partitioning of picocyanobacterial lineages in the oligotrophic northwestern Pacific Ocean

  • Choi, Dong Han;Selph, Karen E.;Noh, Jae Hoon
    • ALGAE
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    • v.30 no.3
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    • pp.223-232
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    • 2015
  • More than 20 and 10 clades / ecotypes of Synechococcus and Prochlorococcus, respectively, have been identified in various oceanic regions. However, their diversity has yet to be thoroughly studied in the northwest Pacific Ocean. Further, spatial distribution of Synechococcus clades in the oligotrophic oceans has been scarcely characterized. To elucidate picocyanobacterial lineage distribution in the northwest Pacific Ocean, 16S-23S internal transcribed spacer sequences of picocyanobacteria were sequenced by barcoded amplicon pyrosequencing method. Additional pyrosequencing library using a primer specific for the Synechococcus subcluster-5.1 was constructed to thoroughly understand Synechococcus diversity in the oligotrophic oceans. In warm pool area, Prochlorococcus was predominant and showed a distinct depthpartitioning between HLII and LL ecotypes. Despite low abundances, diverse Synechococcus clades appeared in the oligotrophic open ocean, showing both vertical and horizontal niche partitioning. Clade II was the predominant Synechococcus clade, especially in upper euphotic depths. In shallow and middle euphotic depths, clades UC-A, III, and CRD1 were distributed broadly. However, a distinct shift in the horizontal distribution was found at ca. $20^{\circ}N$. Conversely, clades XVII and CRD2 dominated at deep euphotic depths and constituted a higher proportion than clade II. These niche-partitioning of Synechococcus clades seemed to be related with temperature, nutrient concentration as well as iron concentration.