• ETRI Journal
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• 제40권5호
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• pp.613-623
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• 2018

The instability of operational channels on cognitive radio networks (CRNs), which is due to the stochastic behavior of primary users (PUs), has increased the complexity of the design of the optimal routing criterion (ORC) in CRNs. The exploitation of available opportunities in CRNs, such as the channel diversity, as well as alternative routes provided by the intermediate nodes belonging to routes (internal backup routes) in the route-cost (or weight) determination, complicate the ORC design. In this paper, to cover the channel diversity, the CRN is modeled as a multigraph in which the weight of each edge is determined according to the behavior of PU senders and the protection of PU receivers. Then, an ORC for CRNs, which is referred to as the stability probability of communication between the source node and the destination node (SPC_SD), is proposed. SPC_SD, which is based on the obtained model, internal backup routes, and probability theory, calculates the precise probability of communication stability between the source and destination. The performance evaluation is conducted using simulations, and the results show that the end-to-end performance improved significantly.

• 한국산학기술학회논문지
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• 제17권10호
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• pp.310-318
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• 2016

본 연구는 도시의 미시적 요소들과 보행량과의 상관관계를 도출하는 것을 목적으로 한다. 보행을 촉진시키는 미시적 요소로 밀도, 다양성, 네트워크 구조, 접근성, 필지 및 건축물 형태, 건축물 전면부 형태 등의 요소를 중심으로 접근했다. 특히, 밀도, 다양성, 접근성 등은 Cervero and Kockelman(1997)의 3Ds(Density, Diversity, Design)와 Ewing et al(2008)이 추가한 2Ds(Distance to Transit, Destination Accessibility)와 관련이 깊은 개념으로 이들은 보행을 촉진시키는 것으로 잘 알려져있다. 이러한 분석을 위해서 2010 서울시 유동인구조사 자료 중 서울시 내 강북지역의 종로구와 중구를 중심으로 분석을 수행하였다. 종로구와 중구 내 보행량을 측정한 지점 1,028개소를 중심으로 반경 500m의 미시적 요소들을 조사하여 데이터를 구축하였다. 분석결과, 기존의 보행량 촉진에 효과적인 요소들인 밀도, 다양성, 접근성 등은 종로구와 중구의 상황에도 유효했다. 또한 건축물의 1층부 형태와 건축물 전면 공간의 형태 역시도 보행량에 유의미한 영향을 주는 것을 도출할 수 있었다. 연구결과는 추후 보행량 촉진을 통한 지속가능한 도시, 회복력 있는 도시 조성의 기초자료가 될 수 있을 것으로 기대된다.

• 한국조명전기설비학회지:조명전기설비
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• 제4권1호
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• pp.54-62
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• 1990

본 연구는 우리나라 전력다소비 건물의 전기설비용량, 전력사용실태를 조사하여 통계적 처리를 함으로써 합리적인 수요율과 부등율 기준을 설정하였다. 설정된 수요율과 부등율 기준을 적용하면 설비투자비 감소, 전력손실 감소, 전기요금 절약 및 설비 이용율 개선에 크게 기여할 수 있다. 그러므로 설정된 수요율과 부등율 기준은 이행 관제규정을 개정하기 위하여 활용되어야 할 것이다.

• 한국의류산업학회지
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• 제23권3호
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• pp.323-336
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• 2021

This study investigated the cognitive process of fashion design images through eye activity tracking. Differences in the cognitive process and gaze activity according to image elements were confirmed. The results of the study are as follows. First, a difference was found between groups in the gaze time for each section according to the model and design. Although model diversity is an important factor leading the interest of observers, the simplicity of the model was deemed more effective for observing the design. Second, the examination of the differences by segments regarding the gaze weight of the image area showed differences for each group. When a similar type of model is repeated, the proportion of face recognition decreases, and the proportion of design recognition time increases. Conversely, when the model diversity is high, the same amount of time is devoted to recognizing the model's face in all the processes. Additionally, there was a difference in the gaze activity in recognizing the same design according to the type of model. These results enabled the confirmation of the importance of the model as an image recognition factor in fashion design. In the fashion industry, it is important to find a cognitive factor that attracts and retains consumers' attention. If the design recognition effect is further maximized by finding service points to be utilized, the brand's sustainability is expected to be enhanced even in the rapidly changing fashion industry.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2001년도 Bulletin of The 5th Asian Design Conference International Symposium on Design Science
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• pp.1.2-1
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• 2001

• 복식
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• 제60권10호
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• pp.88-99
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• 2010

The purpose of this study is to express visual and functional diversity through modifiable design, and to suggest a methodological model. With this view, this study was aimed to departmentalize the case of knitwear in modifiable design of clothes and propose the possibility of variable knit fashion through make the most of knit's characteristics. Four wearable physical clothes using the most of flexible knits' characteristics were made for this study based on the modifiable design on the expressive tendency and analysis of plasticity. The following results were obtained. First, as modifiable knit design can create effects of several dresses in visual aspect and functional aspect, so it has practicality and functionality. Because modifiable clothes required wearer's participation, this have amusement that give enjoyment and freshness to wearer. Second, in mode of wearing, flexibility of knit is suitable character to open & close and change of wearing position. In manipulation, a prearranged plan for line of clothes and good choice of subsidiary materials are important. Third, the characteristics of knits allow using and mixing with different pattern and materials on the two sides of the same cloths except for the some of the parts. Moreover, there is no unraveled thread on the part of knits margin against woven, so it has the broad applicable range for the changeable design. Finally, the form and function, a prearranged plan for modifiable design of clothes have all contributed in creating new structure and patterns in design.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.41-45
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• 2007

Multi-input multi-output (MIMO) system can increase data rate, capacity and bit error rate (BER) performance compare to traditional single antenna system. However MIMO technique is pointed out the problem that has high complexity to design receiver. So a recent trend of research on the MIMO system pays more attention to simplified implementation of receiver structure. In this paper, we propose differential space time block code (STBC) for MIMO system with cyclic delay diversity (CDD). This structure can provide a very close performance to that of the conventional diversity scheme with maximum likelihood (ML) detection without channel estimation block while the receiver structure is highly simplified. Bit error rate (BER) performance of the proposed system is simulated for an AWGN channel by theoretical and simulated approaches. The results of this paper can be applicable to the 4G mobile multimedia communication systems.

• 한국위성정보통신학회논문지
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• 제12권1호
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• pp.120-124
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• 2017

본 본문에서는 Code division multiple access (CDMA) 사용자와 협대역 사용자가 동일 주파수 대역에 존재하는 곳에서 direct sequence/CDMA (DS/CDMA) 오버레이 시스템에 대해 pseudorandom noise (PN) 코드 획득 성능 상의 안테나 다이버시티의 효과가 분석되고 시뮬레이션 되었다. 시뮬레이션 결과는 안테나 다이버시티가 PN 획득 성능에 매우 효과적임을 보인다. 이 논문의 결과는 DS/CDMA 오버레이 환경에서 동기 구조의 설계에 적용될 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.295-297
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• 2007

We design a new rate-3/2 full-diversity orthogonal space-time block code (STBC) for QPSK and 2 transmit antennas (TX) and 4 transmit antennas (TX) by enlarging the signalling set from the set of quaternions used in the Alamouti[I] and extendedcode and using additional members of the set of orthogonal matrices or Quasi-orthogonal matrices and higher than rate-5/4. Selective power scaling of information symbols is used to guarantee full-diversity while maximizing the coding gain (CG) and minimizing the transmitted signal peak-to-minimum power ratio (PMPR). The optimum power scaling factor is derived analytically and shown to outpetform schemes based only on constellation rotation while still enjoying a low-complexity maximum likelihood (ML) decoding algorithm.

• 한국통신학회논문지
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• 제33권12C호
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• pp.1062-1067
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• 2008

ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.