• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.99-106
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• 2023

Now a days, large volumes of data is accumulating in every field due to increase in capacity of storage devices. These large volumes of data can be applied with data mining for finding useful patterns which can be used for business growth, improving services, improving health conditions etc. Data from different sources can be combined before applying data mining. The data thus gathered can be misused for identity theft, fake credit/debit card transactions, etc. To overcome this, data mining techniques which provide privacy are required. There are several privacy preserving data mining techniques available in literature like randomization, perturbation, anonymization etc. This paper proposes an Enhanced Hybrid Privacy Preserving Data Mining(EHPPDM) technique. The proposed technique provides more privacy of data than existing techniques while providing better classification accuracy. The experimental results show that classification accuracies have increased using EHPPDM technique.

• 한국유체기계학회 논문집
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• 제15권2호
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• pp.5-11
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• 2012

In this paper, the heat transfer coefficient measurement techniques using TSP(temperature sensitive paint) were introduced and the results of a comparative study on the heat transfer coefficient measurement by steady state and transient TSP techniques were discussed. The distributions of heat transfer coefficient by a single $60^{\circ}$ inclined impingement jet on a flat surface were measured by both techniques. Tested Reynolds number based on the jet diameter (d) was 30,000 and the distance between jet exit and target plate (L) was fixed at 10d. Results showed that the measured Nusselt number by both techniques indicated significant difference except near the center of impingement jet. Also, the heat transfer coefficients measured by the transient TSP technique were affected by the reference temperature of the jet. Based on the measured data, characteristics of both TSP techniques were analyzed and suggestions for applying them were also given.

• 한국정보통신학회논문지
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• 제4권5호
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• pp.1005-1015
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• 2000

본 논문에서는 무선통신로 채널상에 존재하는 가우스 잡음을 포함한 협대역 A급 임펄스 잡음과 나카가미페이딩 환경에서 하이브리드 CDMA MFSK시스템의 성능을 비교 분석하고, 성능 개선 기법으로 MRC 다이버시티 수신 기법과 부호화 기법을 동시에 채용함으로써 고려되어진 시스템의 성능을 개선시켰다. 결과에 의하면 임펄스 지수가 강할수록 또한. 페이딩 지수가 작을수록 하이브리드 CDMA 시스템에서는 성능이 더욱 열화 됨을 알 수 있었고, 성능 개선 기법으로 BCH 부호화 기법을 채용했을 경우 페이딩 지수가 증가할수록 성능개선의 폭이 큼을 알 수 있었다. 페이딩 지수가 작은 열악한 환경에서는 MRC 다이버시티 수신 기법을 채용하였을 경우가 BCH 부호화 기법을 채용하였을 경우 보다 시스템 성능이 우수하였지만, 페이딩 영향이 감소할수록 BCH 부호화 기법을 채용하였을 경우 시스템 성능이 우수함을 알 수 있었다. 또한 반가우시안 분포와 레일리 페이딩 환경에서 각각의 성능 개선 기법을 단독으로 채용하였을 경우, 음성서비스 품질$(10^{-3})$에 도달할 수 없지만, BCH 부호화 기법과 MRC 다이버시티를 동시에 채용함으로써 강한 임펄스 잡음하에서도 24dB 이상에서 음성서비스 기준 오율을 만족하는 성능 개선 효과를 얻을 수 있었고, 페이딩 지수가(m=3) 이상에서는 강한 임펄스 잡음이 부가되어도 22dB에서 $(10^{-3})$을 만족하고 24㏈ 이상에서는 데이터 서비스 기준$(10^{-5})$ 오율을 만족하는 우수한 성능 개선 효과를 보임으로써 다이버시티 가지수와 부호화의 이득에 의한 에러 성능이 향상되었다.

• Journal of Welding and Joining
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• 제34권1호
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• pp.59-67
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• 2016

The automotive manufactures increase their use of lightweight materials to improve fuel economy and energy usage has a significant influence on the choice of developing materials. To meet this requirements manufacturers are replacing individual body parts with lightweight metals, for these the process treating and painting surfaces is changing. The pre-coated steels are newly developed to avoid the conventional complex and non-environmental painting process in the body-in-white car manufacturing. The development of new joining techniques is critically needed for pre-coated steel sheets, which are electrically non-conductive materials. In the present study, dissimilar combination of pre-coated steel and galvanized steel sheets were joined by the self-piercing rivet, adhesive bonding and hybrid joining techniques. The tensile shear test and free falling high speed crash test were conducted to evaluate the mechanical properties of the joints. The highest tensile peak load with large deformation was observed for the hybrid joining process which has attained 48% higher than the self-piercing rivet. Moreover, the hybrid and adhesive joints were observed better strain energy compared to self-piercing rivet. The fractography analyses were revealed that the mixed mode of cohesive and interfacial fracture for both the hybrid and adhesive bonding joints.

• 한국경영과학회지
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• 제25권3호
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• pp.125-135
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• 2000

Many different statistical and artificial intelligent techniques have been applied to improve the predictability of credit rating. Hybrid models and systems have also been developed by effectively combining different modeling processes or combining the outcomes of individual models. In this paper, we introduced the rough set theory and developed a hybrid credit rating system that combines individual outcomes in terms of rough set theory. An experiment was conducted to compare the prediction capability of the system with those of other methods. The proposed system based on rough set method outperformed the others.

• 경영과학
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• 제19권2호
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• pp.155-168
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• 2002

In this paper, some efficient implementation techniques for the multifrontal method, which can be used to compute the Cholesky factor of a symmetric positive definite matrix, are presented. In order to use the cache effect in the cache-based computer architecture, a hybrid method for factorizing a frontal matrix is considered. This hybrid method uses the column Cholesky method and the submatrix Cholesky method alternatively. Experiments show that the hybrid method speeds up the performance of the supernodal multifrontal method by 5%～10%, and it is superior to the Cholesky method in some problems with dense columns or large frontal matrices.

• Journal of the Korean Data and Information Science Society
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• 제21권4호
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• pp.777-782
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• 2010

We introduce some techniques to decompose the impulse (the unit sample) into several dilated pieces in the discrete time domain. From the decomposition of the impulse, we obtain localized moving averages. Thus we construct hybrid Bollinger bands that may give various strategies for stock traders. By simulations, we report that more than 94% of stock prices of companies in KOSPI 200 are inside this hybrid Bollinger band.

• 한국지능시스템학회논문지
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• 제13권3호
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• pp.366-370
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• 2003

In this research, we suggest a hybrid intelligent Web recommendation systems based on Web data mining and case-based reasoning (CBR). One of the important research topics in the field of Internet business is blending artificial intelligence (AI) techniques with knowledge discovering in database (KDD) or data mining (DM). Data mining is used as an efficient mechanism in reasoning for association knowledge between goods and customers＇ preference. In the field of data mining, the features, called attributes, are often selected primary for mining the association knowledge between related products. Therefore, most of researches, in the arena of Web data mining, used association rules extraction mechanism. However, association rules extraction mechanism has a potential limitation in flexibility of reasoning. If there are some goods, which were not retrieved by association rules-based reasoning, we can＇t present more information to customer. To overcome this limitation case, we combined CBR with Web data mining. CBR is one of the AI techniques and used in problems for which it is difficult to solve with logical (association) rules. A Web-log data gathered in real-world Web shopping mall was given to illustrate the quality of the proposed hybrid recommendation mechanism. This Web shopping mall deals with remote-controlled plastic models such as remote-controlled car, yacht, airplane, and helicopter. The experimental results showed that our hybrid recommendation mechanism could reflect both association knowledge and implicit human knowledge extracted from cases in Web databases.

• 한국농공학회지
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• 제45권2호
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• pp.58-67
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• 2003

Over the last decade fiber-reinforced polymer (FRP) reinforcement consisting of glass, carbon, or aramid fibers embedded in a resin such as vinyl ester, epoxy, or polyester has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. But reinforcing rebar for concrete made of FRP rebar has linear elastic behavior up to tensile failure. For safety a certain plastic strain and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. The same should be required for FRP rebar. Thus, the main object of this study was to develop new type of hybrid FRP rebar Also, this study was evaluated to the mechanical properties of Hybrid FRP rebar. The Manufacture of the hybrid FRP rebar was achieved by pultrusion, and braiding and filament winding techniques. Tensile and interlaminar shear test results of Hybrid FRP rebar can provide its excellent tensile strength-strain behavior and interlaminar stress-strain behavior.

• 한국정보통신학회논문지
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• 제19권1호
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• pp.113-118
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• 2015

추천 시스템은 증가되고 있는 정보에서 사용자가 요구하는 적합한 정보를 선별해 제공해준다. 추천 시스템은 기존에 입력된 정보들을 알고리즘을 통해 선별하는 과정을 거치고 사용자의 정보나 내용 기반으로 정보를 제공한다. 추천 시스템의 문제점으로는 Cold-Start가 있으며, Cold-Start는 새로운 사용자의 정보가 충분하지 않아서 추천 시스템에서 새로운 사용자에게 정보를 추천할 때 발생한다. Cold-Start를 해결하기 위해선 사용자의 정보나 항목 정보가 충족해야 한다. 이에 본 논문에서는 협업 필터링 기법과 내용 기반의 필터링 기법을 혼합한 혼합 필터링 기법 기반으로 Cold-Start 문제를 해결하고 이를 사용하는 영화 추천 시스템을 제안한다.