• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.517-525
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• 2006

In this paper, we present a high-speed RFID data filtering engine designed to carry out filtering under the conditions of massive data and massive filters. We discovered that the high-speed RFID data filtering technique is very similar to the high-speed packet classification technique which is used in high-speed routers and firewall systems. Actually, our filtering engine is designed based on existing packet classification algorithms, Bit Parallelism and Aggregated Bit Vector(ABV). In addition, we also discovered that there are strong temporal relations and redundancy in the RFID data filtering operations. We incorporated two kinds of caches, tag and filter caches, to make use of this characteristic to improve the efficiency of the filtering engine. The performance of the proposed engine has been examined by implementing a prototype system and testing it. Compared to the basic sequential filter comparison approach, our engine shows much better performance, and it gets better as the number of filters increases.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.238-240
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• 2004

정보 통신 기술의 발달로 엄청난 양의 정보가 World Wide Web을 통해 저장되고 공유된다. 특히, 사용자가 WWW을 이용하여 필요한 정보를 얻고자할 때, 가장 많이 사용되는 것이 Web search engine이다. 그러나 Web search engine의 algorithm 자체의 부정확성과 악의적으로 작성된 Web page로 인해 search engine 결과가 사용자의 요구와 일치하지 못하는 문제가 발생한다. 본 논문에서는 여러 Web search algorithm 중에서 Web structure management 기법을 중심으로 문제점을 분석하고 이를 해결할 수 있는 수정된 algorithm을 제시한다. 마지막으로 제시된 algorithm이 spamming page를 filtering하는 과정을 예시하여 논증한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.29-34
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• 2002

This study presents the process of the continuous-time system identification for unknown nonlinear systems. The Radial Basis Function(RBF) error filtering identification model is introduced at first. This identification scheme includes RBF network to approximate unknown function of nonlinear system which is structured by affine form. The neural network is trained by the adaptive law based on Lyapunov synthesis method. The identification scheme is applied to engine and the performance of RBF error filtering Identification model is verified by the simulation with a three-state engine model. The simulation results have revealed that the values of the estimated function show favorable agreement with the real values of the engine model. The introduced identification scheme can be effectively applied to model-based nonlinear control.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.5
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• pp.380-388
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• 2019

Jet engine modulation(JEM) signals are widely used for target recognition. These signals coming from a potentially hostile aircraft provide specific information about the jet engine. In order to obtain the number of blades, which is uniquely provided by the JEM signal, one must extract the spool rate, which is the rotation speed of the blades. In this paper, we propose an algorithm to extract the spool rate from a weak JEM signal. A criterion is developed to extract the spool rate from the JEM signal by analyzing the intensity of the JEM signal component. The weak signal is first subjected to a high-pass filtering-based process, which modifies it to facilitate spool rate extraction. We then apply a peak detection process and extract the spool rate. The technique is simpler than the existing CEMD or WD method, is accurate, and greatly reduces the time required.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.845-850
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• 2012

Currently power of the diesel engine is increasing continuously, where the wearing problems become more severe. The wearing happens irregularly inside the cylinder, which causes a high burden to the marine engine. In this paper, a novel scheme to measure the wearing and to represent the engine states has been proposed. To monitoring the states of the marine engine efficiently, a laser displacement sensor has been utilized to measure the wearing happening inside the marine engine. To eliminate the noise signals in the distance measurement, the wavelet transform has been adopted, which is robust against the noises caused by vibrations. An engine simulator is designed to develop the system for measuring the engine wears, where the superiority of the wavelet transform against the conventional filtering schemes has been demonstrated.

• Proceedings of the Korean Society for Information Management Conference
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• 1997.08a
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• pp.37-53
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• 1997

The huge size of Internet does not allow ordinary information seekers to search information with ease. Now, it is almost impossible to navigate the ocean of information without effective search tools. Web search engine has been the most effective technology for information retrieval on WWW. But recently, the need for new search tools on WWW or Internet has increased drastically. Currently, there are many on-going researches on the related topics. In this survey, we categorize the new search tools into four types: monitoring systems, filtering systems, browsing assistant systems, recommending systems. These example systems are examined. We are especially interested in WWW information filtering. It is studied how to apply the information filtering techniques to WWW, The application is not so straightforward like Email, Newswire filtering systems. As a result of this study, a simple WWW information filtering system is proposed.

• Korean Journal of Computational Design and Engineering
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• v.17 no.2
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• pp.97-110
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• 2012

High performance sensors and modern data logging technology with real-time telemetry facilitate system fault diagnosis in a very precise manner. Fault detection, isolation and identification in fault diagnosis systems are typical steps to analyze the root cause of failures. This systematic failure analysis provides not only useful clues to rectify the abnormal behaviors of a system, but also key information to redesign the current system for retrofit. The main barriers to effective failure analysis are: (i) the gathered data (event) logs are too large in general, and further (ii) they usually contain noise and redundant data that make precise analysis difficult. This paper therefore applies suitable pre-processing techniques to data reduction and feature extraction, and then converts the reduced data log into a new format of event sequence information. Finally the event sequence information is decoded to investigate the correlation between specific event patterns and various system faults. The efficiency of the developed pre-filtering procedure is examined with a terminal box data log of a marine diesel engine.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.23-28
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• 2012

Recently, due to the increasing demand for mobile devices, mobile searching market is rapidly growing. However, there is the limit of screen size, when searching for mobile devices, various results should be shown at a glance. The reason is that results are important given that up to 43 percent of people tend to check only first page. In this paper, a set of keywords for searching will be used to find out the users' interests. Users were divided into groups after going through Collaboration filtering. Therefore, the result of this experiment, reduced time for searching and improved quality of searching were confirmed.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.641-644
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• 2006

윈도우 자체에서 제공하는 방화벽이나 기존의 솔루션으로 제공되고 있는 방화벽에 대한 한계점을 보완하고자 기존의 패킷 필터링 방화벽과 어플리케이션 필터링 방화벽의 장점을 모두 가지고 있는 하이브리드형의 방화벽을 제안하고, 사용자들이 방화벽 시스템의 부하를 줄이기 위해서 각종의 서비스들을 제공할 때 사용자 프로파일의 context에 기반을 둔 확장된 필터링 엔진을 제안한다.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.522-530
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• 2010

We developed functional synthetic lubricant for internal combustion engine oil, which would improve engine oil performance for internal combustion engine and extend engine life. We made base oil by synthesizing nonanoic acid, 1.1.1-trimethylol propane (which has good bio-degradability) and pentaerythrytol ester. We synthesized catalyst using p-toluene sulfonic acid 0.15 wt% and coloring-prevention agent hypo-phosphorus acid 0.18 wt% at 180-$190^{\circ}C$. Reaction temperature was increased at the rate of $10^{\circ}C$ for every 1 hour. When acid value reached below 3, reaction was completed. After cooling and deoxidization, we washed it by distilled water two times. After dehydration and filtering, we obtained trimethylol propane tripelargonate (TMTP) and pentaerythrytol tetrapelargonate (PETP) at yields of 96 % and 98 % respectively.