• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.371-376
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• 2004

Distributed Network Protocol Version 3.0 (DNP3.0) is the communication protocol developed for the interoperability between a RTU and a central control station of SCADA in the power utility industry. In this paper DNP3.0 is implemented by using HDL with FPGA and C program on Hitachi H8/532 processor. DNP3.0 is implemented from physical layer to network layer in hardware level to reduce the computing load on a CPU. Finally, the ASIC for DNP3.0 has been manufactured from Hynix Semiconductor. The commercial feasibility of the hardware through the communication test with ASE2000 and DNP Master Simulator is performed. The developed protocol becomes one of IP, and can be used to implement SoC for the terminal device in SCADA systems. Also, the result can be applicable to various industrial controllers because it is implemented in HDL.

• The Research Journal of the Costume Culture
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• v.14 no.2
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• pp.334-351
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• 2006

The purpose of study is to examine fashion bags reflected women's changing lifestyle, their needs and vogue in modern environment since 20th century. Today fashion bags can be divided into practical bag, evening bag, luxury bag and utility bag. Practical bag is a type of tote which is perfect for working mom or women carrying lots of things on a daily basis. Evening bag is a symbol of femininity in respect for its handmade artistry and impracticality by its small size. Luxury bag embodies human desire for high quality and being part of prestige of luxury brand regardless of its cost. Utilitarian bag was coming from military or sports gear and are popular among young generation armed with mobile computing or crazy about popular music and all kinds of sports. In contemporary fashion culture, fashion bags play an important roles on balancing women's social and domestic life as functional and decorative accessory.

• ETRI Journal
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• v.37 no.5
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• pp.845-855
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• 2015

To enable the coexistence of Licensed Assisted Access (LAA) and Wi-Fi in 5 GHz unlicensed bands, a new channel access mechanism is proposed. Accounting for the fairness between LAA and Wi-Fi, the proposed mechanism finds the optimal transmission time ratio by adaptively adjusting the transmission durations for LAA and Wi-Fi. In addition, we propose a new analytical model for the distributed coordination function of IEEE 802.11 through some modifications of conventional analytical models for saturation and non-saturation loads. By computing the activity ratio of Wi-Fi, the proposed analytical model is able to control the time ratio between LAA and Wi-Fi, which is required for practical implementation of the proposed access mechanism. Through numerical simulations, the proposed channel access mechanism is compared with conventional methods in terms of throughput and utility.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2597-2599
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• 2003

전력산업 환경변화에 따라 전력산업 전반에 걸친 고기능, 고효율의 정보기술(IT) 적용 필요성이 증대되고 있으며, 특히 향후 모바일 통신기술은 현장업무 처리능률과 고객에 대한 서비스를 대폭 향상시킬 수 있는 기술분야로서 연구개발의 필요성이 매우 클 것으로 예상되고 있다. 향후 무선인터넷 수요의 폭발적 증가가 예상되는 가운데 국내외적으로 이동통신업체를 포함한 제반 솔루션 공급업체, 민간/Utility 등 활용위주의 기업체, 학계 및 관련 연구소 등에서 향후 막대한 시장성과 성장성을 예측하여 모바일 컴퓨팅의 연구개발과 투자를 집중하고 있으며, 한전의 경우 G2B, B2B, B2E, B2C를 전반적으로 아우르는 다양한 업무범위와 전력업무 고유의 특수성을 감안한 때 모바일컴퓨팅 적용연구는 향후 이동통신의 최적 활용을 대비한다는 측면에서 연구개발을 추진하고 있으며, 본 논문에서는 연구개요 및 방향을 전반적으로 소개하고자 한다.

• International Journal of Contents
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• v.9 no.3
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• pp.29-34
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• 2013

This study attempted to compare usability of auditory interfaces, which is a comprehensive concept that includes safety, utility, effectiveness, and efficiency, in personal computing environments: verbal messages (speech sounds), earcons (musical sounds), and auditory icons (natural sounds). This study hypothesized that verbal messages would offer higher usability than earcons and auditory icons, since the verbal messages are easy to interpret and understand based on semiotic process. In this study, usability was measured by a set of seven items: ability to inform what the program is doing, relevance to visual interfaces, degree of stimulation, degree of understandability, perceived time pressure, clearness of sound outputs, and degrees of satisfaction. Through the experimental research, the results showed that verbal messages provided the highest level of usability. On the contrary, auditory icons showed the lowest level of usability, as they require users to establish new coding schemes, and thus demand more mental effort from users.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2003.05a
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• pp.400-409
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• 2003

Collaborative filtering (CF) recommendation is a knowledge sharing technology for distribution of opinions and facilitating contacts in network society between people with similar interests. The main concerns of the CF algorithm are about prediction accuracy, speed of response time, problem of data sparsity, and scalability. In general, the efforts of improving prediction algorithms and lessening response time are decoupled. We propose a three-step CF recommendation model which is composed of profiling, inferring, and predicting steps while considering prediction accuracy and computing speed simultaneously. This model combines a CF algorithm with two machine learning processes, SOM (Self-Organizing Map) and CBR (Case Based Reasoning) by changing an unsupervised clustering problem into a supervised user preference reasoning problem, which is a novel approach for the CF recommendation field. This paper demonstrates the utility of the CF recommendation based on SOM cluster-indexing CBR with validation against control algorithms through an open dataset of user preference.

• Journal of the Korean Statistical Society
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• v.19 no.2
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• pp.151-159
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• 1990

Regression diagnostics often involves assesment of the changes that result from deleting multiple cases. Diagnostic mehtodology based on global influence measure, however, needs prohibitive computing time. As an alternative, Cook (1986) developed influence approach in which it is checked whether a minor modification of specifiation influences key results of an analysis. In line with Cook's development, we propose and study an inflence derivative method that yields both the magnitude and direction of case influences. The utility of our methodology is highlighted when case influence derivatives are plotted in a lower demensional space. Such plots are especially effective in unmasking "masked" observations in least squares regression and in robust regression also. We give several illustrations.strations.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.148-151
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• 2013

가상화 기반 클라우드 컴퓨팅 환경은 비용 효율성과 자원 활용 측면에서 강점을 갖고 있으나 주어진 응용의 행태에 따른 적절한 자원할당 방법이 필요한 상황이다. 그러므로 클라우드 컴퓨팅 환경에서 다양하게 구성된 가상클러스터와 응용 특성을 서로 비교 분석해야 한다. 이를 위해 본 논문의 목적은 OpenStack 기반 가상화 자원을 사용하여 생성된 클러스터 환경을 상태분석 도구인 Ganglia를 이용하여 분석한다. 분석에 사용되는 Utility 함수의 결과는 각 응용에서 요구되는 성능을 클라우드 컴퓨팅 환경이 만족시키는지 판단할 수 있는 자료가 될 것이다.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.1
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• pp.35-42
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• 2016

Developments in power electronics have enabled the widespread application of Pulse Width Modulation (PWM) inverters, notably for connecting renewable systems to the grid. This study demonstrates that a high-quality power can be achieved using a stand-alone inverter, whereby the comparison between the power quality of the stand-alone inverter with battery storage (off-grid) and the power quality of the utility network is presented. Multi-loop control techniques for a single phase stand-alone inverter are used. A capacitor current control is used to give active damping and enhance the transient and steady state inverter performance. A capacitor current control is cheaper than the inductor current control, where a small current sensing resistor is used. The output voltage control is used to improve the system performance and also control the output voltage. The inner control loop uses a proportional gain current controller and the outer loop is implemented using internal model control proportional-integral-derivative to ensure stability. The optimal controls are achieved by using the Sisotool tool in MATLAB/Simulink. The outcome of the control scheme of the numerical model of the stand-alone inverter has a smooth and good dynamic performance, but also a strong robustness to load variations. The numerical model of the stand-alone inverter and its power quality are presented, and the power quality is shown to meet the IEEE 519-2014. Furthermore, the power quality of the off-grid system is measured experimentally and compared with the grid power, showing power quality of off-grid system to be better than that of the utility network.

• Journal of KIISE
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• v.44 no.1
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• pp.21-26
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• 2017

In recent years, new technologies such as Internet of Things, Cloud Computing and Big Data are being widely used. And the type and amount of data is dramatically increasing. This makes security an important issue. In terms of leakage of sensitive personal information. In order to protect confidential information, a method called anonymization is used to remove personal identification elements or to substitute the data to some symbols before distributing and sharing the data. However, the existing method performs anonymization by generalizing the level of quasi-identifier hierarchical. It requires a higher level of generalization in case where k-anonymity is not satisfied since records in data table are either added or removed. Loss of information is inevitable from the process, which is one of the factors hindering the utility of data. In this paper, we propose a novel anonymization technique using decision tree based machine learning to improve the utility of data by minimizing the loss of information.