• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.99-108
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• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.562-570
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• 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)
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• v.9 no.6
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• pp.2095-2110
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• 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
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• v.43 no.5
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• pp.553-564
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• 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.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.19-22
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• 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).

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.307-310
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• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1306-1312
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• 2000

The quality loss of a X-band transmitter has been derived by means of MC simulation. The transmitter as a payload of LEO(Low Earth Orbit) satellite is capable of the down transmission the image data of hundreds Mbps generated from the Electro-Optical Instrument in real time. The parameters such as data asymmetry amplitude unbalance,phase unbalance, wave shaping and channel interference are included in the quality loss simulation Assuming that normally distributed gaussian noise is simply added to the channel, the quality loss of 0.7 dB has been obtained through this simulation based on a 95% confidence interval. The obtained quality loss can be applied to the link budgets as an additional loss item.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.14-28
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• 2009

The PageRank algorithm is an important component for ranking Web pages in Google and other search engines. While many improvements for the original PageRank algorithm have been proposed, it is unclear which variations (and their combinations) provide the "best" ranked results. In this paper, we evaluate the ranking quality of the well-known variations of the original PageRank algorithm and their combinations. In order to do this, we first classify the variations into link-based approaches, which exploit the link structure of the Web, and knowledge-based approaches, which exploit the semantics of the Web. We then propose algorithms that combine the ranking algorithms in these two approaches and implement both the variations and their combinations. For our evaluation, we perform extensive experiments using a real data set of one million Web pages. Through the experiments, we find the algorithms that provide the best ranked results from either the variations or their combinations.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.403-408
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• 2010

The sensor nodes can be installed in the environment in which the temperature change is considerable, such as desert, urban, and data center. Particularly, because the output power becomes less than the targeted power if a temperature is increasing, link quality is degraded and packet losses are occurred. In order to compensate the temperature changes, existing schemes detect the change of the link quality between nodes and control transmission power through a series of feedback process. However, these approaches can cause heavy overhead by additional control packets. In this paper, we propose the T2PC(Temperature-aware Transmission Power Control) to keep up the link quality despite temperature variation. At each node, T2PC compensates the attenuated link quality by controlling the transmission power based on the local temperature measurement. In addition, the packet reception ratio can be improved with less control packets than ones required in existing transmission power control methods based on the feedback control.

• International Journal of Quality Innovation
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• v.7 no.1
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• pp.195-205
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• 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.