• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.51-54
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• 2000

Due to the emerging of high-speed network, lots of interests of access to remote data have increased. Those interests motivate using of Cooperative Caching that uses remote cache like local cache by sharing other clients' cache. The conventional algorithm like GMS(Global Memory Service) has some disadvantages that occurred bottleneck and decreasing performance because of exchanges of many messages to server or manager. On the other hand, Hint-based algorithm resolves a GMS's server bottleneck as each client has hint information of all blocks. But Hint-based algorithm also causes some problems such as inaccurate information in it, if it has too old hint information. In this paper, we offer the policy that supplement bottleneck and inaccuracy； by using file identifier that can search for the lookup table and by exchanging oldest block information between each client periodically.

• Journal of Digital Contents Society
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• v.10 no.4
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• pp.633-637
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• 2009

In this paper, we present the reuse module library generating algorithm and register-transfer (RT) library generating algorithm considering the power consumption of reuse module for field-programmable gate array (FPGA) technology mapping in order to implement into the circuit for calculating power consumption. To realize the circuit of calculation of power consumption, the FPGA is selected. Considering lookup table (LUT) conditions of selected FPGA, technology mapping process is conducted to minimize the total power consumption. With these information, the circuit is realized using suitable given power consumption among allocated results of modules.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.71-78
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• 2009

One of main concepts involved in regional small nuclear reactors is unmanned remote control. Internet-based virtual private networks provide environments for the remote monitoring and control of geographically-dispersed systems, and with the advances in communication technologies, the potential of networks for real time control and automation becomes enormous. However, networked control has some problems. The most critical is delay in signal transmission, which degrades system stability and performance. Therefore, a networked control system should be designed to account for delay. This paper proposes some design approaches for a delay-tolerant system that can guarantee predetermined stability margins and performance. To accomplish this, the reactor plant is modeled with consideration of uncertainties. With this model, three kinds of controllers are developed using different methods. The designed systems are compared with respect to stability and performance, and a second-order controller designed using the table lookup method was found to give the most satisfactory results.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.15-18
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• 2003

Flash memory becomes more important for its fast access speed, low-power, shock resistance and nonvolatile storage. But its native restrictions that have limited 1ifetime, inability of update in place, different size unit of read/write and erase operations need to managed by FTL(Flash Translation Layer). FTL has to control the wear-leveling, address mapping, bad block management of flash memory. In this paper, we focuses on the fast access to address mapping table and proposed the way of faster valid page search in the flash memory using the VPLT(Valid Page Lookup Table). This method is expected to decrease the frequency of access of flash memory that have an significant effect on performance of read and block-transfer operations. For the validations, we implemented the FTL based on Windows CE platform and obtained an improved result.

• Journal of IKEEE
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• v.4 no.2 s.7
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• pp.173-180
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• 2000

In this paper, we interpreted and evaluated the relation between the sensation of equilibrium and biomedical signal automatically by applying the fuzzy theory. We induced the vertigo by using the caloric test, and presented the correlation between vertigo and biomedical signal by using the quantification method. We objectively analyzed the organic relation of the biomedical signal by fuzzy rule design using the table-lookup scheme and obtained good result in recognizing the level of the sensation of equilibrium.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.584-592
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• 2008

In this paper, we propose a new model of the magnetic control force exerted on the levitation object in magnetic levitation systems. The model assumes that the magnetic force is a function of the voltage applied to an electromagnet and the position of a levitation object. The function is not explicitly expressed but represented through a 2D lookup table constructed from the experimentally measured data. Unlike the conventional model that reveals only local characteristics of the magnetic force, the proposed model shows global characteristics satisfactorily. Specially devised measurement equipment is utilized in order to gather the data required for model construction. An experimental procedure to construct the model is presented. We apply the proposed model to designing a sliding mode controller for a lab-built magnetic system. The validity of the proposed model is illustrated by comparing the performances of the controller adopting the conventional model with that of the controller adopting the proposed model.

• Journal of information and communication convergence engineering
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• v.4 no.2
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• pp.79-83
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• 2006

We present two techniques based on lookup tables to reduce complexity of the well-known Schnorr-Euchner (SE) sphere decoder (SD) without introducing performance degradation. By the aid of lookup tables, the computational loads caused by the SE enumeration and decision feedback are reduced at the cost of higher storage capacity. Simulation results are provided to verify performance and complexity of the proposed decoders.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.43-50
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• 2001

The IP routing uses the longest-matching prefix to determine the destination. Fast lookup should be required for the high speed routing. We propose a modified LC-trie, called multiple LC-trie, which is suitable data structure for fast address-lookups in software implementation. To reduce the number of memory accesses, our scheme analyzes the distribution of IP address access pattern, and constructs multiple LC:-tries for frequently accessed IP addresses. Our experimental results show that our scheme can perform faster than the original LC-trie schemes.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1928-1931
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• 2002

Orthogonal Frequency Division Multiplexing or OFDM is a form of multi-carrier modulation technique. High spectral efficiency, robustness to channel fading, immunity to impulse interference, uniform average spectral density, capability of handling very strong echoes and less on linear distortion are among the favorite properties of OFDM. Even though there are many advantages of OFDM, t has two main drawbacks: high Peak to Average Power Ratio (PAPR) and frequency of offset. In this paper, the issue of PAPR in OFDM is discussed. A new algorithm is proposed to reduce PAPR by selecting the input sequences property using a lookup table.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.40-42
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• 2005

Jini는 네트워크를 통해 사람이나, 기기, 프로그램이 특정 자원을 찾거나 사용하고자 할 때, 관리자의 개입 없이 유연하게 동작하게 하는 분산 미들웨어의 하나이다. 기존의 Jini 서비스는 Lookup Service 데몬(Httpd, Reggie. Rmid)이 실행되어 Discovery, Join, Lookup, Service Invocation의 과정을 통해 이루어지는데, 데몬 fault 발생 시 어떠한 해결점이 없다는 것이 문제점이다. 이에 본 논문에서는 Jini 서비스 데몬 손실로 인한 Jini 서비스의 Fault 문제를 해결하기 위해 Grid환경 하에서 그리드 서비스를 사용하여 Jini 서비스에 Fault Tolerance를 제공하는 시스템의 구조와 방법을 제시한다.