• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.2
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• pp.119-124
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• 2016

According to the expansion of smartphone penetration and development of wearable device, personal context information can be easily collected. To use this information, the context aware recommender system has been actively studied. The key issue in this field is how to deal with the context information, as users are influenced by different contexts while rating items. But measuring the similarity among contexts is not a trivial task. To solve this problem, we propose context aware post-filtering to apply the context compensation. To be specific, we calculate the compensation for different context information by measuring their average. After reflecting the compensation of the rating data, the mechanism recommends the items to the user. Based on the item recommendation list, we recover the rating score considering the context information. To verify the effectiveness of the proposed method, we use the real movie rating dataset. Experimental evaluation shows that our proposed method outperforms several state-of-the-art approaches.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.163-165
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• 2003

Over the past several years, the application extent of the real-time systems is being expanded with the progress of civilization. An effort to minimize power consumption at the system is being accomplished in several fields from the design of an analog/digital circuit up to the device level Things of this effort have included the power optimum-technique to minimize power consumption at the digital logic circuit and the dynamic managed skill by means o( the decision of the operating system. In this paper, we designed of low power system by using Power-optimized method. As an effective low-power design, we designed the low power system which it has a monitoring system within the main board and a personal computer.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.304-307
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• 2013

Reverse engineering of semiconductor devices utilizes delayering processes, in order to identify how the interconnection lines are stacked over transistor gates. Cu metal has been used in recent fabrication technologies, and de-processes becomes more difficult with the shrinking device dimensions. In this article, reverse engineering technologies to reveal the Cu interconnection lines and Cu via-plugs embedded in dielectric layers are investigated. Stacked dielectric layers are removed by $CF_4$ plasma etching, then the exposed planar Cu metal lines and via-plugs are selectively delineated by wet chemical solution, instead of the commonly used plasma-based dry etch. As a result, we have been successful in extracting the layouts of multiple layers within a system IC, and this technique can be applicable to other logic IC, analog IC, and CMOS IC, etc.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.166-168
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• 2007

A dimmable ballast system for the electrodeless fluorescent lamp is proposed. The proposed scheme is composed of the electronic ballast and the wireless communication part. They both are realized with one EPLD (Erasable Programmable Logic Device). The dimming levels of each lamps can be controlled by a management system through wireless communication technology. 10 ballasts are used for the group lighting system and the experiment results show the system works well.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.3
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• pp.26-36
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• 2010

This paper provides a description of the combustion model to obtain an accurate dynamic engine phenomena that satisfies real-time simulation for model-based engine control. The combustion chamber is modeled as a storage device for mass and energy. The combustion process is modeled in terms of a two-zone model for the burned and unburned gas fractions. The mass fraction burnt is modeled in terms of a Wiebe function. The instantaneous net engine torque is calculated from the engine speed and the instantaneous piston work. The modeling accuracy has been tested with a cylinder pressure data on a test bench and also the ability of real-time simulation has been checked. The results show that combustion model yields sufficiently good performance for the model-based control logic design. However the influence factors effected on model accuracy are some room for improvement.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.387-394
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• 1995

With respect to the effectiveness of types of knowledge on human diagnostic performance, the results of several experiments claimed that training with diagnostic rules (procedural knowledge) is more effective than training that provides theoretical knowledge (principle knowledge). However, we usually have the idea that understanding the principles of system dynamics is necessary for diagnosis in some situations. In this study, we pointed out some problems in the previous experiments that force to reinterpret their experimental conclusions. Accordingly, we conducted an experiment to reinvestigate the value of theoretical knowledge in two problem situations. A simulator system, which is named DLD, that is to diagnose an electronic device was created for this purpose. It is a context-free digital logic circuit which includes forty-one gates of three basic types. Our experiment investigated the marginal effects of theoretical knowledge over common diagnostic rules. The experimental results showed that the effectiveness of the instruction in theoretical knowledge is dependent on the complexity of diagnostic situations. This adds up an experimental evidence against the presumed ineffectiveness of theoretical knowledge and forward reasoning in fault diagnosis. Furthermore, the result suggests the source of the use of theoretical knowledge.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1477-1480
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• 2003

본 논문에서는 실시간 데이터 및 보안데이터, 영상데이터 통을 전송할 때 잡음으로 인해 발생되는 데이터 오류를 효과적으로 복원하기 위해 오류 정정 능력이 뛰어난 터보코드를 적응하여 신뢰성 있는 영상전송 시스템을 실현하였다. 영상처리 시스템에서는 CCTV, 비디오 카메라 등에서 나오는 NTSC(National Television System Committee) 영상 신호를 비디오 디코더를 통해 A/D 변환하여 출력하였다. 변환된 디지털 영상정보는 두 개의 영상필드로 출력되며 그중 하나의 필드가 선택되는 알고리즘을 EPLD(Erasable Programmable Logic Device) 로직회로로 구성하여 디지털 영상 데이터를 절반으로 줄이는 시스템을 구현하였다. 터보코드의 부호기, 복호기 시스템에서는 실수연산이 가능한 DSP(Digital Signal Processor)를 사용하여 터보코드를 구현하였으며, 터보코드의 성능을 좌우하는 인터리버부분은 블록 인터리버를 적용하여 설계하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.215-220
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• 2005

Nowadays, various speech processing systems are being introduced in the fields of robotics. However, real-time processing and high performances are required to properly implement speech processing system for the autonomous robots. Achieving these goals requires advanced hardware techniques including intelligent software algorithms. For example, we need nonlinear amplifier boards which are able to adjust the compression radio (CR) via computer programming. And the necessity for noise reduction, double-buffering on EPLD (Erasable programmable logic device), simultaneous multi-channel AD conversion, distant sound localization will be explained in this paper. These ideas can be used to improve distant and omni-directional speech recognition. This speech processing system, based on embedded Linux system, is supposed to be mounted on the new home service robot, which is being developed at KIST (Korea Institute of Science and Technology)

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.8-16
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• 1992

Despite recent advances in electrical switch architectures, the practical switch performance is limited by both the technological and physical constraints of electrical device and wiring. Though an optical switch can have good features, optical devices are of poor quality. Therefore, we propose and study the switching architecture based on free-space optical interconnections and electrical logic devices. And an exchanging method using packets with a parallel form is introduced to solves the blocking problem of the switch that resulted from switching packets with a serial form. The free-space optical interconnections overcome the defects of electrical switch, such as, the complex connections of the wires. The proposed and demonstrated switch is nonblocking, simple and high performable. Other attractive features of the proposed switch include the guarantee of first-in first-out packet sequence. In this thesis, we also discuss the performance of proposed switch and show the experimental results of the 4$\times$4 switch.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.91-97
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• 2004

This paper describes the design of a 2-phase stepping motor driver using CPLD(Complex Programmable Logic Device). The driver IC such as L297(SGS-Thomson Microelectronics), which is mostly used has some difficulties in PWM control because of the switching noise of power MOSFETs. It causes current ripple and acoustic noise. To improve theses characteristics, we proposed a new current control method that the output PWM frequency is almost constant using a digital filter. Also we proposed constant current method for 1-2 phase(half step) excitation. The proposed method is implemented with CPLD(Xilinx, XC9572-PC44). Experimental results show the effectiveness of the proposed method.