• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.17-22
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• 2022

Due to the recent advances in high-speed communication technologies as well as the easy production of high-quality video contents, IPTV is becoming increasingly popular. Meanwhile, as the number of IPTV channels increases, channel search time to find the desired channel keeps increasing. In this paper, we discuss how to improve the channel search latency in IPTV, and introduce caching and prefetching techniques that are widely used in memory management systems. Specifically, we adopt memory replacement, prefetching, and caching techniques in IPTV channel search interfaces and show the effectiveness of these techniques as the number of channels are varied.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.10
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• pp.556-564
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• 2004

This paper presents an application of parallel Genetic Algorithm-Tabu Search(GA-TS) algorithm to search an optimal solution of a reconfiguration in distribution system. The aim of the reconfiguration of distribution systems is to determine switch position to be opened for loss minimization in the radial distribution systems, which is a discrete optimization problem. This problem has many constraints and very difficult to solve the optimal switch position because it has many local minima. This paper develops parallel GA-TS algorithm for reconfiguration of distribution systems. In parallel GA-TS, GA operators are executed for each processor. To prevent solution of low fitness from appearing in the next generation, strings below the average fitness are saved in the tabu list. If best fitness of the GA is not changed for several generations, TS operators are executed for the upper 10% of the population to enhance the local searching capabilities. With migration operation, best string of each node is transferred to the neighboring node aster predetermined iterations are executed. For parallel computing, we developed a PC-cluster system consisting of 8 PCs. Each PC employs the 2 GHz Pentium Ⅳ CPU and is connected with others through ethernet switch based fast ethernet. To show the usefulness of the proposed method, developed algorithm has been tested and compared on a distribution systems in the reference paper. From the simulation results, we can find that the proposed algorithm is efficient and robust for the reconfiguration of distribution system in terms of the solution qualify. speedup. efficiency and computation time.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.116-124
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• 2005

This paper presents an application of the parallel Genetic Algorithm-Tabu Search (GA- TS) algorithm, and that is to search for an optimal solution of a reconfiguration in distribution systems. The aim of the reconfiguration of distribution systems is to determine the appropriate switch position to be opened for loss minimization in radial distribution systems, which is a discrete optimization problem. This problem has many constraints and it is very difficult to solve the optimal switch position because of its numerous local minima. This paper develops a parallel GA- TS algorithm for the reconfiguration of distribution systems. In parallel GA-TS, GA operators are executed for each processor. To prevent solution of low fitness from appearing in the next generation, strings below the average fitness are saved in the tabu list. If best fitness of the GA is not changed for several generations, TS operators are executed for the upper 10$\%$ of the population to enhance the local searching capabilities. With migration operation, the best string of each node is transferred to the neighboring node after predetermined iterations are executed. For parallel computing, we developed a PC-cluster system consisting of 8 PCs. Each PC employs the 2 GHz Pentium IV CPU and is connected with others through switch based rapid Ethernet. To demonstrate the usefulness of the proposed method, the developed algorithm was tested and is compared to a distribution system in the reference paper From the simulation results, we can find that the proposed algorithm is efficient and robust for the reconfiguration of distribution system in terms of the solution quality, speedup, efficiency, and computation time.

• The Journal of Society for e-Business Studies
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• v.4 no.3
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• pp.179-196
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• 1999

A cyber shopping mall is a place where consumers acquire the product information and make purchase decision in the cyber space. Even though there are many advantages over traditional malls, there are still several limitations to do shopping in an existing cyber mall. One of them is the absence of efficient search tool to handle various products specifications. Existing search systems usually support the "keyword search only" with limited product information. Consumers spend lots of their time and efforts in searching products and comparing them. Recently, some web sites provide the shopping mall comparison service that supports the additional search conditions such as price and maker. These services improve the situation but it is not still acceptable. In this paper, we propose an intelligent product search system based on a mediator which supports various conditional search for each product. Our system provides consumers with search results that satisfy purchase specifications. Our system is implemented in Visual basic and pert and experimental results show satisfactory performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.35
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• pp.107-114
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• 1995

This paper proposes the Tabu Search algorithm to minimize mean tardiness in the parallel machine scheduling problem. The algorithm reduces the computation time by employing restricted neighborhood and produces an efficient solution in this problem.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.105-108
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• 2002

Although asynchronous designs have become a promising way to develop complex modern digital systems, there is a few complete design framework for VLSI designers who wish to use automatic CAD tools. Especially, high-level synthesis is not widely concerned until now. In this paper we Proposed a method for high-level synthesis of asynchronous systems as a part of an asynchronous design framework. Our method performs scheduling, allocation, and binding, which are three subtasks of high-level synthesis, in simultaneous using a transformational approach. To deal with complexity of high-level synthesis we use neighborhood search algorithm such as Tabu search.

• Journal of information and communication convergence engineering
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• v.9 no.1
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• pp.27-31
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• 2011

This paper describes the optimization of spectrum sensing in terms of the throughput of a cognitive radio (CR) system. Dealing with the optimization problem of spectrum sensing, this paper evaluates the throughput of a CR system by considering such situations as the penalty time of a channel search and incumbent user (IU) detection delay caused by a missed detection of an incumbent signal. Also, this paper suggests a serial channel search scheme as the search method for a vacant channel, and derives its mean channel search time by considering the penalty time due to the false alarm of a vacant channel search. The numerical results suggest the optimum sensing time of the channel search process using the derived mean channel search time of a serial channel search in the case of a sensing hardware structure with single radio frequency (RF) path. It also demonstrates that the average throughput is improved by two separate RF paths in spite of the hardware complexity of an RF receiver.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.5
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• pp.73-83
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• 2016

NAVER provides search frequency data of search terms via its DataLab service (http://datalab.naver.com/). Using this data, this paper examines the relation between the search frequency of firm's name and its future stock returns. Our results show that the search frequency of firm's name is a new investor attention measure, which is different from previously explored attention measures such as extreme returns, turnover, etc. Firms that go through higher search frequency this week tend to have higher returns in the next week. We do not find return reversal in the long run for the firms with higher search frequency. Furthermore, the extent to which search frequency affects stock returns becomes more pronounced following market-wide attention grabbing events. Our results indicate that search frequency incorporates information for future stock returns.

• The Journal of Society for e-Business Studies
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• v.20 no.2
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• pp.1-14
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• 2015

In this paper, we investigate the relationship between Internet search trends and stock market. Under the assumption that investors may use Internet search engine to obtain information for companies of their interests before taking actual investment actions, the relationship between the changes on Internet search volume and the fluctuation of trading volume as well as stock price of a company is analyzed with actual market data. A search trend investment strategy that reflects the changes on Internet search volume is applied to large enterprises' group and to small and medium enterprises' (SMEs) group, and the correlation between profit rate and trading volume is analyzed for each company group. Our search trend investment strategy has outperformed average stock market returns in both KOSPI and KOSDAQ markets during the seven-year study period (2007~2013). It is also shown that search trend investment strategy is more effective to SMEs than to large enterprises. The relationship between changes on Internet search volume and stock trading volume is stronger at SMEs than at large enterprises.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8C
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• pp.742-753
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• 2005

In this paper, we propose a rapid and reliable signal acquisition scheme for UWB (Ultra Wide Band) systems in typical indoor wireless channels. The proposed scheme is a two-step search with different thresholds and search window applied to a single correlator, where each step utilizes the single-dwell search with the bit reversal. Simulation results in IEEE 802. I5 Task Group .3a UWB indoor wireless channel show that the proposed scheme for the LHWB signals can achieve significant reduction of the required mean acquisition time as compared to the conventional single-dwell bit reversal search and double-dwell bit reversal search with more complex structure employing two correlators for various threshold levels. In addition, it is also observed that the proposed scheme can achieve much faster and reliable signal acquisition in noisy environments.