• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.8
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• pp.1049-1054
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• 2018

Keyword searching used in the past as a method of finding similar patents, and automated classification by machine learning is using in recently. Keyword searching is a method of analyzing data that is formalized through data refinement. While the accuracy for short text is high, long one consisted of several words like as document that is not able to analyze the meaning contained in sentences. In semantic analysis level, the method of automatic classification is used to classify sentences composed of several words by unstructured data analysis. There was an attempt to find similar documents by combining the two methods. However, it have a problem in the algorithm w the methods of analysis are different ways to use simultaneous unstructured data and regular data. In this paper, we study the method of extracting keywords implied in the document and using the LDA(Latent Semantic Analysis) method to classify documents efficiently without human intervention and finding similar patents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.370-377
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• 2004

In this paper, we present an adaptive modulation technique for orthogonal frequency division multiplexing (OFDM) for broadband wireless communications. Also, using improved channel prediction, we enhance the performance of adaptive OFDM in high mobility environments. Adaptive modulation technique has been shown to achieve reliable high-rate data transmission over frequency-selective fading channel when OFDM is employed. This scheme requires the accurate channel information between two stations for a better performance. In an outdoor high mobility environment, most of adaptive OFDM systems have to be given the channel information transmitted from the receiver. Even if it is possible, there is some delay. Moreover, the channel impulse response between two stations is very rapidly varied. If the channel information is obsolete at the time of transmission, then poor system performance will result. In order to solve this problem, we propose adaptive OFDM with improved channel predictor. The proposed bit allocation algorithm has a lower complexity and the proposed scheme mitigates the effect of channel delay. Robust approach is less sensitive to outdated channel information. Performance results show that the proposed scheme can achieve considerable performance enhancement.

• Journal of Communications and Networks
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• v.14 no.2
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• pp.188-194
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• 2012

Cognitive networks (CNs) are capable of enabling dynamic spectrum allocation, and thus constitute a promising technology for future wireless communication. Whereas, the implementation of CN will lead to the requirement of an increased energy-arrival rate, which is a significant parameter in energy harvesting design of a cognitive user (CU) device. A well-designed spectrum-sensing scheme will lower the energy-arrival rate that is required and enable CNs to self-sustain, which will also help alleviate global warming. In this paper, spectrum sensing in a multi-user cognitive ad hoc network with a wide-band spectrum is considered. Based on the prospective spectrum sensing, we classify CN operation into two modes: Distributed and centralized. In a distributed network, each CU conducts spectrum sensing for its own data transmission, while in a centralized network, there is only one cognitive cluster header which performs spectrum sensing and broadcasts its sensing results to other CUs. Thus, a wide-band spectrum that is divided into multiple sub-channels can be sensed simultaneously in a distributed manner or sequentially in a centralized manner. We consider the energy consumption for spectrum sensing only of an analog-to-digital convertor (ADC). By formulating energy consumption for spectrum sensing in terms of the sub-channel sampling rate and whole-band sensing time, the sampling rate and whole-band sensing time that are optimal for minimizing the total energy consumption within sensing reliability constraints are obtained. A power dissipation model of an ADC, which plays an important role in formulating the energy efficiency problem, is presented. Using AD9051 as an ADC example, our numerical results show that the optimal sensing parameters will achieve a reduction in the energy-arrival rate of up to 97.7% and 50% in a distributed and a centralized network, respectively, when comparing the optimal and worst-case energy consumption for given system settings.

• Journal of Digital Contents Society
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• v.14 no.1
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• pp.51-57
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• 2013

Storage device based on Flash Memory have many attractive features such as high performance, low power consumption, shock resistance, and low weight, so they replace HDDs to a certain extent. An Storage device based on Flash Memory has FTL(Flash Translation Layer) which emulate block storage devices like HDDs. A garbage collection, one of major functions of FTL, effects highly on the performance and the lifetime of devices. However, there is no de facto standard for new garbage collection algorithms. To solve this problem, we propose File Clustering Algorithm. File Clustering Algorithm respect to update page from same file at the same time. So, these are clustered to same block. For this mechanism, We propose Page Allocation Policy in FTL and use MIN-MAX GAP to guarantee wear leveling. To verify the algorithm in this paper, we use TPC Benchmark. So, The performance evaluation reveals that the proposed algorithm has comparable result with the existing algorithms(No wear leveling, Hot/Cold) and shows approximately 690% improvement in terms of the wear leveling.

• The Journal of Fisheries Business Administration
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• v.47 no.1
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• pp.47-61
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• 2016

This study is aimed to analyze economical meaning and problems on the industrial differentiation of Korean laver industry. Based on the surveyed data, the export value of korean laver has increased over 28 times for last 20 years($10 million to $300 million) and the separation of farming and processing was an important success factor of rapid growth of korean laver industry. However, the result of the survey shows that the farming profit is 534.1 won out of the total price for a bunch of dried laver, 3,566.3 won. So, farming profit counts for just 15 percent of total price. In contrast, the processing profit is 1,143.5 won and it is 32.1 percent of total price. This means that laver farmers are not being guaranteed their profit properly. This phenomenon is occurred due to lower status of first-hand processors(which produce dried laver) to second-hand processors(which produce seasoned laver) due to advanced payment given by second-hand processors. So, fist-hand processors should provide their product in the price which was designated by second-hand processors. Besides, despite of many business risks caused from climate change and environmental pollution, the market price of raw laver has steadily decreased. For sustainable prosperity of korean laver industry, imbalance on korean laver industry concerning profit sharing is need to be changed. In future, self-processing of dried laver in fishery household and enhancing the role of The Fisheries Cooperative Union in laver industry can be considered.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.117-122
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• 2017

In a wireless communication system, increasing the channel capacity with a limited frequency is a problem in all frequency bands. Increasing the frequency bandwidth and increasing the output can increase the channel capacity, but sometimes the communication is not possible due to interference noise. If the radio frequency allocation is set to world standardization such as WRC or ITU-R, each country has strict control over regulations. This is because one wireless communication system should not affect other systems. We present the results of a study on scenarios and analysis of radio waves to be installed inside and outside the aircraft without interfering with the wireless LAN.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.78-86
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• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• Journal of Arbitration Studies
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• v.25 no.2
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• pp.71-96
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• 2015

This paper deals with the annulment of the ICSID(International Centre for Settlement of Investment Disputes) arbitral award. The annulment of the ICSID is characterized by the fact that it can be made possible through the special committee of ICSID only. The annulment of the ICSID was constructed on the premise that it is not an appeal procedure. However in the initial period, it was strongly criticized as it allowed new trials or duplicated many of the functions of an appeal and it broke down the boundary between the two systems. Although the trend seemed to be corrected through its 2nd and 3rd generations, it was still criticized for functioning as a new trial. It is approaching its 4th generation. On the other hand, with the activation of investment agreement arbitration based on ICSID and FTA, a certain degree of consistency is required for the ICSID arbitralaward. Also, with the emphasis on the public features of the arbitration for the investment agreement, the necessity of an appeal system is presented. The ICSID Secretariat published the "Opinion on the Appeal Procedure" in 2004 but as the system was criticized as too early due to the cost allocation problem and others, its adoption of an appeal procedure has been delayed. This paper focuses on how the currently incomplete ICSID arbitration judgment annulment system shall be used. Although it is still hardto expect the quality and consistent arbitral award annulment in the ICSID, this paper suggests that the "annulment without the actual new trial" using the restricted authority of a special commission in a creative way shall be pursued rather than just the actual new trial with or without annulment, thus going back to the original concept of the ICSID arbitral award annulment.

• Journal of Arbitration Studies
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• v.25 no.2
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• pp.3-17
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• 2015

For many years commentators have requested more active regulation of attorney ethics in international arbitration. Gradual deterioration of ethical standards in international arbitration will bring disrepute and, once its reputation is lost, it could take decades to rebuild confidence. The first reason for increasing unethical behavior is that there is no ethical code generally applied to all lawyers participating in international arbitration. A second reason might be that nobody is actively regulating attorneys in international arbitration. The first step to solve this problem is that major arbitration institutions should cooperate to enact a uniform code of conduct to be generally applied to all attorneys representing parties in international arbitration. Recently, IBA and LCIA prepared guidelines on party representation in international arbitration, and the guidelines will help attorneys follow uniform standardsof ethics. However, this will not be sufficient. There should be a regulating body to monitor attorney ethics and take sanctions against unethical attorneys accordingly. Arbitrators, who can see unethical behavior by attorneys from the closest distance, are the most appropriate regulating force rather than courts of arbitration seat or an attorney's licensing country. Of course, arbitrators don't have powers to withdraw or suspend an attorney's license, but they have powers to control attorneys'behavior within arbitration proceedings such as an allocation of fees and costs, barring the assertion of claims or defenses, drawing adverse inferences, or precluding the submission of evidence or testimony. Furthermore, arbitrators should be provided with such obligation as active control of attorney ethics. Even arbitration institutions should participate by imposing on an attorney who is a repeat offender a suspension from appearing in future arbitrations. Unethical behavior will decrease through concerted actions among arbitrational institutions to introduce a uniform code of conduct and to empower arbitrators for more efficient regulation of attorney ethics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1663-1668
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• 2005

There have been numerous researches regarding the QoS guarantee in packet switching networks. IntServs, based on a signaling mechanism and scheduling algorithms, suggesting promising solutions, yet has the crucial complexity problem so that not enough real implementations has been witnessed. Flow aggregation is suggested recently to overcome this issue. In order to aggregated flows fairly so that the latency of the aggregated flows is bound, however, a non-work conserving scheduler is necessary, which is not very popular because of its another inherent complexity. We suggest a non-work conserving scheduler, the Round Robin with Virtual Flow (RRVF), which is a variation of the popular Deficit Round Robin (DRR). We study the latency of the RRVF, and observe that the non-work conserving nature of the RRVF yields a slight disadvantage in terms of the latency, but after the aggregation the latency is greatly reduced, so that e combined latency is reduced. We conclude that the flow aggregation through RRVF can actually reduce the complexity of the bandwidth allocation as well as the overall latency within a network.