• 대한수학회지
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• 제33권3호
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• pp.541-555
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• 1996

The Fourier transform plays a central role in the theory of distribution on Euclidean spaces. Although Lebesgue measure does not exist in infinite dimensional spaces, the Fourier transform can be introduced in the space $(S)^*$ of generalized white noise functionals. This has been done in the series of paper by H.-H. Kuo [1, 2, 3], [4] and [5]. The Fourier transform $F$ has many properties similar to the finite dimensional case; e.g., the Fourier transform carries coordinate differentiation into multiplication and vice versa. It plays an essential role in the theory of differential equations in infinite dimensional spaces.

• 전자통신동향분석
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• 제24권3호
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• pp.91-102
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• 2009

FCC(Federal Communications Commission 미국 연방통신위원회)는 2008년 11월 스펙트럼 사용 효율을 높이고 새로운 서비스 도입을 용이하게 하기 위해 TV White Spaces를 대상으로 주파수 공유 기술인 Cognitive Radio 기술을 적용하기로 하고 관련 규정을 개정하였다. FCC는 TV White Spaces에서 고정 서비스와 개인/휴대서비스기기 사용을 허용하기로 방침을 정하고 2009년 5월 12일 DTV 전환 완료 이후 관련 기기 사용을 허용하기로 하였다. 본 논문에서는 FCC의 법규 개정 현황과 함께 이를 기술적으로 뒷받침하기 위한 IEEE 802.22, TV White Spaces ECSG, ECMA에서의 표준화 동향을 설명하고, 핵심 기술로서 스펙트럼 센싱 기술, 무선자원관리 기술, PHY/MAC 관련 기술 개발 동향에 대해 요약 기술하였다.

• Journal of Communications and Networks
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• 제16권2호
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• pp.238-244
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• 2014

A key technical challenge in TV white spaces is the efficient spectrum usage without interfering with primary users. This paper considers available spectrum discovery scheme using in-band sensing signal to support super Wi-Fi services effectively. The proposed scheme in this paper adopts non-contiguous orthogonal frequency-division multiplexing (NC-OFDM) to utilize the fragmented channel in TV white space due to microphones while this channel cannot be used in IEEE 802.11af. The proposed solution is a novel available spectrum discovery scheme by exploiting the advantages of a sensing signaling. The proposed method achieves considerable improvement in throughput and delay time. The proposed method can use more subcarriers for transmission by applying NC-OFDM in contrast with the conventional IEEE 802.11af standard. Moreover, the increased number of wireless microphones (WMs) hardly affects the throughput of the proposed method because our proposal only excludes some subcarriers used by WMs. Additionally, the proposed method can cut discovery time down to under 10 ms because it can find available channels in real time by exchanging sensing signal without interference to the WM.

• 대한수학회지
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• 제11권1호
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• pp.53-54
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• 1974

• 대한수학회보
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• 제21권1호
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• pp.1-5
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• 1984

The notion of linear 2-normed spaces was introduced by S. Gahler ([8,9,10,11]), and these space have been extensively studied by C. Diminnie, R. Ehret, S. Gahler, K. Iseki, A. White, Jr, and others. For nonzero vectors x,y in X, let V(x,y) denote the subspace of X generated by x and y. A linear 2-normed space (X,v) is said to be strictly convex ([3]) if v(x+y,z)=v(x,z)+v(y+z) and z not.mem.V(x,y) imply that y=ax for some a>0. Some characterizations of strict convexity for linear 2-normed spaces are given in [1,3,4,5,12]. Also, a linear 2-normed space (X,v) is said to be strictly 2-convex ([6]) if v(x,y)=v(x,z)=v(y,z)=1/3v(x+z, y+z)=1 implies that z=x+y. These space have been studied in [2,4,6,13]. It is easy to see that every strictly convex linear 2-normed space is always strictly 2-convex but the converse is not necessarily true. Throughout this paper, let (X,v) denote a linear 2-normed space.

• International Journal of Internet, Broadcasting and Communication
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• 제5권1호
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• pp.1-5
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• 2013

Co channel interference and adjacent channel interference of (WiBro) into Wireless LAN (WLAN) in TV White Spaces (TVWS) is evaluated through Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. As a result, in the case of co channel interference, the minimum distance between WiBro Mobile Station (MS) and WLAN User Equipment (UE) should be 210 m to allow the maximum transmitter power of WiBro UE of 25 dBm. The transmit power of WiBro BS have to be reduced to -4.96 dBm.

• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.6-11
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• 2016

본 논문은 무전원의 백스케터 통신이 결합된 RF 에너지 하비스팅 시스템에서 주파수 자원의 효율을 높이기 위한 스펙트럼 센싱 알고리즘을 연구했다. 송신기 측에 스팩트럼 센싱 알고리즘을 이용해서 유휴주파수 대역을 찾고, 찾은 유휴주파수 대역 중에서 페이딩 영향이 적은 채널을 선택한다. 알고리즘을 적용한 송신기는 페이딩의 영향이 적은 신호를 송신하여, 수신측에서 수신신호의 간섭을 완화시키고, 수신신호강도를 향상시킬 수 있다. 따라서, 백스케터 통신이 결합된 RF 에너지 하비스팅에 스팩트럼 센싱 알고리즘이 적용된 송신기를 사용하고, 컴퓨터 시뮬레이션 결과를 통해 백스케터 통신의 BER과 수신거리별 수신세기, 그리고 RF 에너지 하비스팅의 성능이 이전보다 향상하는 것을 확인하였다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.300-303
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• 2009

The purpose of this study is to grasp the preference of colors in housing spaces by different type of personality and color preference by classifying dwellers various characteristics by MBTI to obtain basic informations for the color plan that satisfies their inner desire. The results of this study are as followed. Firstly, we could say about the color distribution of living spaces like that. The ceiling and general wall showed that N(white) systems and YR of bright tone was mostly distributed. The color of floor showed that the calm tone of YR was mostly distributed. Secondly, as for the favored colors of finishing material at each space, the biggest distribution of preference color was found as N(white) group(series) in case of ceilings. As for general walls, bright tone of N(white) group showed most in living rooms. In case of that of the floor, it showed the largest distribution of calm tone of YR. Point wall was preferred bright and brilliant in various kinds of color. Thirdly, as in favor of colors of closing materials, sensible types(S) are concentrated on common color groups, on the other hand, intuition types(N) prefer color groups of various kinds not only general preferred colors.

• ETRI Journal
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• 제38권2호
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• pp.314-325
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• 2016

This paper examines the resource gain that can be obtained from the creation of clusters of nodes in densely populated areas. A single node within each such cluster is designated as a "hotspot"; all other nodes then communicate with a destination node, such as a base station, through such hotspots. We propose a semi-distributed algorithm, referred to as coordinated cognitive tethering (CCT), which clusters all nodes and coordinates hotspots to tether over locally available white spaces. CCT performs the following these steps: (a) groups nodes based on a modified k-means clustering algorithm; (b) assigns white-space spectrum to each cluster based on a distributed graph-coloring approach to maximize spectrum reuse, and (c) allocates physical-layer resources to individual users based on local channel information. Unlike small cells (for example, femtocells and WiFi), this approach does not require any additions to existing infrastructure. In addition to providing parallel service to more users than conventional direct communication in cellular networks, simulation results show that CCT can increase the average battery life of devices by 30%, on average.

• 한국실내디자인학회논문집
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• 제21권5호
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• pp.135-144
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• 2012

Since Seoul was selected as the world design capital at the end of 2007, the endeavors to modernize the Korean unique beauty is becoming more tangible. Especially, the commercial spaces to be used by the general public and tourists have the value for study in the respect that such spaces for the national iconic images and have a large and far-reaching effect to transmit the national identity. Therefore, this study analyzed the design coordination properties in the Koreanity expression found in the modern commercial spaces. the foundation for the analysis was based on Leonard Koren's work on the arrrangement rhetoric theory, 'Arranging things(2003), and the contents of Korean expression were reviewed with professional jounals. the results are as follows: First, the design coordination properties in the Koreanity expression shown in modern commercial spaces are black-white contrast, natural materials, curved shapes, brevity, and simple beauty. Especially, some elements such as wood, traditional Korean papers, stones, mid-to-low chroma natural colors, checked patterns, and crazy patterns are used with overlapping and it is viewed that it is necessay to more aggressively seek for the disappeared traditional elements in the Korean modeling properties. Second, the concrete images of Korean expressions could be summarized as four adjective image groups, Natural, Subtitle, Gentle and Magnificent.