• 산업경영시스템학회지
• /
• 제22권51호
• /
• pp.99-108
• /
• 1999

B-ISDN link dimensioning is often known as a difficult problem because of the characteristics of Asynchronous Transfer Mode(ATM) such as various Quality of Services of different service requirements, and the statistical multiplexing resulting from virtual path/virtual circuit connections. In this paper, we propose a nonlinear integer optimization model for dimensioning B-ISDN considering the statistical multiplexing effects of virtual path connections(VPCs) and the modularity of resources allocated to a transmission link. The algorithm based on the simultaneous linear approximation technique as well as some numerical results will be also presented.

• 한국통신학회논문지
• /
• 제22권3호
• /
• pp.562-570
• /
• 1997

In Direct Sequence Code Division Multiple Access(DS/CDMA) communication systems, it is important to contraol the power of reverse link channel evenly for overall channel capacity. To control the reverse link powers efficiently, it is necessary to estimate signal quality of each reverse link channel. In this paper, we discuss a method to estimate the signal-to-noise ratio(SNR) for each channel by measuring the powers of pilot and noises. Computer simulations are done to show the effectiveness of the scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권6호
• /
• pp.2095-2110
• /
• 2015

This paper presents a design for a throughput-efficient online relay selection scheme for dual-hop multi-relay cooperative networks. Problems arise with these networks due to unpredictability of the relaying link quality and high time-consumption to probe the dual-hop link. In this paper, we firstly propose a novel probing and relaying protocol, which greatly reduces the overhead of the dual-hop link estimation by leveraging the wireless broadcasting nature of the network. We then formulate an opportunistic relay selection process for the online decision-making, which uses a tradeoff between obtaining more link information to establish better cooperative relaying and minimizing the time cost for dual-hop link estimation to achieve higher throughput. Dynamic programming is used to construct the throughput-optimal control policy for a typically heterogeneous Rayleigh fading environment, and determines which relay to probe and when to transmit the data. Additionally, we extend the main results to mixed Rayleigh/Rician link scenarios, i.e., where one side of the relaying link experiences Rayleigh fading while the other has Rician distribution. Numerical results validate the effectiveness and superiority of our proposed relaying scheme, e.g., it achieves at least 107% throughput gain compared with the state of the art solution.

• Steel and Composite Structures
• /
• 제43권5호
• /
• pp.553-564
• /
• 2022

Many existing reinforced concrete (RC) structures need to be strengthening for reason such as poor construction quality, low ductility or designing without considering seismic effects. One of the strengthening methods is strengthening technique with eccentrically braced frames (EBFs). The characteristic element of these systems is the link element and its length is very important in terms of seismic behavior. The link element of Y shaped EBF systems (YEBFs) is designed as a short shear element. Different limits are suggested in the literature for the link length. This study to aim experimentally investigate the effect of the link length for the suggested limits on the behavior of the RC frame system and efficiency of strengthening technique. For this purpose, a total of 5 single story, single span RC frame specimens were produced. The design of the RC frames was made considering seismic design deficiencies. Four of the produced specimens were strengthened and one of them remained as bare specimen. The steel YEBFs were used in strengthening the RC frame and the link was designed as a shear element that have different length with respect to suggested limits in literature. The length of links was determined as 50mm, 100mm, 150mm and 200mm. All of the specimens were tested under cyclic loads. The obtained results show that the strengthening technique improved the energy consumption and lateral load bearing capacities of the bare RC specimen. Moreover, it is concluded that the specimens YB-2 and YB-3 showed better performance than the other specimens, especially in energy consumption and ductility.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.19-22
• /
• 2005

In order to achieve high capacity and reliable link quality in user communication, this paper proposes a new concept of virtual cell: the Dual Virtual Cell(DVC), and DVC employment strategy based on DWCS. The proposed system uses two kinds of virtual cell. One is the AVC(Active Virtual Cell) which exists for actual traffic and the other is the CVC(Candidate Virtual Cell) which contains a set of candidate antennas to protect user's link quality from performance degradation or interruption. And also this system aims to reduce MT's overloads and acheive a prompt link change successfuly by introducing DVC structure which makes it possible for network to monitor real-time channel and to conrol communication links. The proposed system constructs DVC by using antenna selection method and improves frame error performance with employing Space-Time Trellis Code(STTC).

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2015년도 추계학술발표대회
• /
• pp.307-310
• /
• 2015

한국군은 각 무기체계별로 미군/NATO 전술데이터링크 및 한국형 전술데이터링크 구축을 통해 합동 및 연합 NCW 수행능력 향상을 위해 노력하고 있다. 이에 따라, 본 논문에서는 전술데이터링크에 대해 고찰한 후 전술데이터링크의 한국군 미래 무기체계 적용 방안을 제시하고자 한다.

• 한국통신학회논문지
• /
• 제25권9A호
• /
• pp.1306-1312
• /
• 2000

저궤도 관측위성에 탑재된 전자광학 카메라(Electro Optical Instrument)에서 생성되는 지상 표적의 영상데이터 (수 백 Mbps)를 실시간 지상 수신소로 전송하는 X-밴드 송신기에 대한 quality loss를 MC 방식의 시뮬레이션으로 산출하였다. 본 quality loss 시뮬레이션에는 QPSK 변조기의 데이터 비대칭(data asymmetry), I Q 채널간의 신호 크기 및 위상편차 불균형(unbalance), 채널결합기(OMUX)의 채널필터에 의한 변조파형 정형화 및 채널간섭 등의 변수가 포함되었다. 무선 구간의 잡음채널을 가산성 가우시안 백색잡음으로 가정할 때, 신뢰도 95 %를 기준한 시뮬레이션에서 X-밴드 송신기의 quality loss 0.7 dB를 구했으며, 이 quality loss는 데이터 링크의 링크버짓(link budget)에서 부가적인 손실항으로 반영되었다.

• 전자공학회논문지CI
• /
• 제46권5호
• /
• pp.14-28
• /
• 2009

PageRank 알고리즘은 구글(Google)등의 검색 엔진에서 웹 페이지의 순위(rank)를 정하는 중요한 요소이다. PageRank 알고리즘의 순위 품질(ranking quality)을 향상시키기 위해 많은 변형 알고리즘들이 제안되었지만 어떤 변형 알고리즘(혹은 변형 알고리즘들간의 조합)이 가장 좋은 순위 품질을 제공하는지가 명확하지 않다. 본 논문에서는 PageRank 알고리즘의 잘 알려진 변형 알고리즘들과 그들 간의 조합들에 대해 순위 품질을 평가한다. 이를 위해, 먼저 변형 알고리즘들을 웹의 링크(link) 구조를 이용하는 링크기반 방법(Link-based approaches)과 웹의 의미 정보를 이용하는 지식기반 방법(Knowledge-based approaches)으로 분류한다. 다음으로, 이 두 가지 방법에 속하는 알고리즘들을 조합한 알고리즘들을 제안하고, 변형 알고리즘들과 그들을 조합한 알고리즘들을 구현한다. 백만 개의 웹 페이지들로 구성된 실제 데이터에 대한 실험을 통해 PageRank의 변형 알고리즘들과 그들 간의 조합들로부터 가장 좋은 순위 품질을 제공하는 알고리즘을 찾는다.

• 한국정보과학회논문지:정보통신
• /
• 제37권5호
• /
• pp.403-408
• /
• 2010

센서 노드는 사막, 도시, 데이터 센터등과 같이 온도의 변화가 심한 환경에 설치될 수 있다. 특히 온도가 증가하게 되면 설정한 파워에 비해 출력되는 파워가 감쇄되기 때문에 RSSI와 같은 링크 품질의 저하를 초래하며, 패킷 손실이 발생될 수 있다. 무선 환경에서 온도의 변화를 보상하기 위한 노드간에 링크 품질의 변화를 파악하고 일련의 피드백 과정을 통하여 전송파워 제어하는 기존의 방법이 있으나, 추가적인 제어 패킷들이 많이 발생하는 문제점이 있다. 본 논문에서는 이러한 온도 변화에 따른 링크품질의 유지를 위하여 T2PC(Temperature-aware Transmission Power Control)를 제안하였다. T2PC는 각 노드에서 자체적으로 얻을 수 있는 온도정보를 이용하여 전송파워를 제어함으로서 감쇄된 랭크 품질을 보상하도록 하였다. 또한 기존의 피드백을 이용한 전송파워 제어 기법보다 적은 컨트롤 패킷으로 패킷 수신율을 향상시켰다.

• International Journal of Quality Innovation
• /
• 제7권1호
• /
• pp.195-205
• /
• 2006

Both the total quality management (TQM) and learning organization (LO) appear to be promising approaches for organizational transformation towards a more effective, efficient, and responsive organization in the past. The evolutionary development and theory supports for these two fields are distinct but they appear to have more in common than they have in distinctiveness. However, there is little synergy developed between these two fields both in academic research and industrial applications. It is possibly due to the fact that both the academia and industry are taking a limiting polarized view of TQM and LO and hence not getting the benefits of linking the two. This paper tries to establish a link between the organizational learning capability and the quality culture for TQM implementation based on a case study on the largest vocational education institution, the Vocational Training Council, of Hong Kong. The study reveals that there is a strong positive correlation between organizational learning capability and quality culture. The exploratory explanations for the links between the organizational learning capability constructs and the quality culture constructs are also discussed in this paper. The findings of the study support other literatures that TQM should be embedded in LO and serves as an enabler for organizational learning (OL) in transforming and creating organizations which continuously expand their abilities to change and shape their future.