• 한국정밀공학회지
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• 제23권12호
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• pp.80-87
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• 2006

Seals are usually made from elastomer, a kind of rubber, and it has the non-linearity and hyper-elasticity. U-type seals are used to prevent the leakage of internal fluid sealed in hydraulic actuator because they have more excellent performance than O-rings or rectangular seals. As a core part of hydraulic actuator, U-type seal gives much effect on performance and reliability of actuator. This study considers an NBR U-type seal under high pressure of a hydraulic actuator, and provides its deformation, stress-strain characteristic and contact force using the non-linear finite element analysis. Analysis results are compared with the experimental ones performed by the self-developed testing equipment. Verification result shows that this study presents a good application process for the effective design of U-type seals under high operation pressure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.425-428
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• 1997

Effectiveness of corrective machining algorithm is verified experimentally in this paper by performing corrective lapping work to single side and double sides hydrostatic tables. Lapping is applied as machining method. Machining information is calculated from measured motion errors by applying the algorithm, without information on rail profile. It is possible to acquire 0.13pm of linear motion error, 1.40arcsec of angular motion error in the case of single side table, and 0.07pm of linear motion error, 1.42arcsec of angular motion error in the case of double sides table. The experiment is performed by the unskilled person after he experienced a little of preliminary machining. Experimental results show that corrective machining algorithm is very effective, and anyone can improve the accuracy of hydrostatic table by using the algorithm.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.171-178
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• 2013

This paper discusses to conduct experimental verification of two types of micro electric vehicles (EV) in order to realize improvement in electric mileage and shorten a charging time of the battery. First, electric double layer capacitor (EDLC) systems to use as a secondary battery are proposed. The internal resistance of EDLC is small compared with a rechargeable battery, and it is suitable for momentary charge-discharge of EV. Next, control circuits of the capacitors to increase the regenerative electric power are utilized. Then, a novel method to charge a main battery of the EV is introduced. Finally, experimental results demonstrate the validity of the proposed method.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.807-813
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• 2006

The objective of this study is to develop a rule-based fault detection algorithm and an experimental verification using an artificial air handling unit. To develop an analytical algorithm which precisely detects a tendency of faulty component, energy equations at each control volume of AHU were applied. An experimental verification was conducted on the HVAC simulator. The rule based FDD algorithm isolated a faulted sensor from HVAC components in summer and winter conditions.

• 설비공학논문집
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• 제12권1호
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• pp.12-19
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• 2000

The multi type heat pump system may provide more energy savings and better environmental conditions than the single type heat pump system may do. In order to design a multi type heat pump system, it may be recommended to develop the system simulation program, which can predict the characteristics of the system such as unit capacities, power consumptions, and system COP's. In this study, the steady state simulation program of the multi type heat pump system was developed. The results from the simulation program were compared with those from the experimental tests which were performed in the environmental chamber, Cooling tests show 3.11% and 0.94% of error in capacity and COP, and heating tests show 3.30% and 1.90% of error in capacity and COP, respectively. Therefore, the steady state simulation program developed for this study can effectively be used for the design and the performance prediction of the multi type heat pump system.

• 초등상담연구
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• 제6권1호
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• pp.49-71
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• 2007

The purpose of this study was to examine the effects of a career group counseling program on the career maturity and achievement motivation of elementary school underachievers. This study targeted the fifth grader underachievers. Twenty underachievers, whose pre-test homogeneity in career maturity and achievement motivation was verified, were allocated to an experimental group and a control group by 10 underachievers each. The program was conducted for a total of 12 sessions, twice per week, and each session lasted 80 minutes. For verification of the program effects in this study, MANOVA and ANOVA were carried out for pre- and post-score tests between the groups, and repeated-MANOVA and paired t-test were peformed to look into the changes within a group by using SPSS/WIN(version 12.0) in terms of statistical analyses. The findings in this study are as follows: First, as a result of post test for the experimental and control groups, and difference verification of post and pre-tests within the experimental group, both career maturity and sub-factors of career maturity demonstrated significant differences. Second, as a result of difference verification of the pre- and post-tests within the experimental group, achievement motivation significantly improved, but there was no statistically significant difference in achievement motivation in the post-test of experimental and control groups. However, of the sub-factors of the achievement motivation, self-confidence and Interest in the long-term future significantly improved. Third, we can see that the career group counseling program provided opportunities for the underachievers to search their own character, interest, and aptitude, and broadly encounter the world of occupations. Also, we can infer that the underachieves had active and developmental attitudes towards future dreams and their current efforts. As noted above, the career group counseling program proved that it has a positive effect to the improvement of the elementary school underachievers' career maturity and achievement motivation in some variables.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제6권4호
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• pp.448-456
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• 2000

설계되는 시스템의 규모가 커지고 복잡해지므로 이를 빠른 시간 내에 효율적으로 검증하기 위한 상위 단계에서의 검증 기술의 개발이 중요하게 되었다. 본 연구에서는 하드웨어와 소프트웨어가 혼합되어 있는 시스템을 위한 상위 단계에서의 검증기술을 개발하였다. 에뮬레이션 또는 시뮬레이션만을 수행하는 것보다 빠르고 우수하게 기능적으로 검증하기 위해, 하드웨어와 소프트웨어 부분으로 분할한 후 인터페이스 회로를 이용하여 구현 가능하도록 하였다. 그리고, 상위 단계의 회로를 쉽게 하드웨어를 이용하여 검증하기 위한 설계 지침들을 제시하였다. 본 방법을 이용하여 리드-솔로몬 디코더 회로에 대한 검증을 수행한 결과 시뮬레이션만을 수행한 경우에 비하여 modified Euclid 알고리즘 수행 블록은 12,000배 이상의 속도로 검증을 수행할 수 있었으며, 전체 검증 시간도 반 이하로 줄었다.

• ETRI Journal
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• 제28권3호
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• pp.320-328
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• 2006

Using biometrics to verify a person's identity has several advantages over the present practice of personal identification numbers (PINs) and passwords. To gain maximum security in a verification system using biometrics, the computation of the verification as well as the storing of the biometric pattern has to take place in a smart card. However, there is an open issue of integrating biometrics into a smart card because of its limited resources (processing power and memory space). In this paper, we propose a speaker verification algorithm using a support vector machine (SVM) with a very few features, and implemented it on a 32-bit smart card. The proposed algorithm can reduce the required memory space by a factor of more than 100 and can be executed in real-time. Also, we propose a hardware design for the algorithm on a field-programmable gate array (FPGA)-based platform. Based on the experimental results, our SVM solution can provide superior performance over typical speaker verification solutions. Furthermore, our FPGA-based solution can achieve a speed-up of 50 times over a software-based solution.

• 한국음향학회지
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• 제29권3호
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• pp.216-221
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• 2010

본 논문에서는 Gaussian Mixture Model (GMM)-supervector의 Mahalanobis 거리측정 방법 기반의 Support Vector Machine (SVM) 커널을 이용한 새로운 화자인증 방법을 제안한다. 제안된 GMM-supervector SVM 커널방식은 GMM 방식과 SVM 방식을 결합한 방식으로서, GMM 파라미터에 의해 형성된 화자 및 비 화자 GMM-supervectors의 화자인증 임계값을 Mahalanobis 거리측정 방법기반의 SVM 커널에 적용함으로써 화자인증 정확도를 높인다. 제안한 방식의 성능 측정을 위해 20명의 화자를 대상으로 문장독립형 화자인증 실험을 수행하여 기존에 사용되고 있는 GMM, SVM, Kullback-Leibler (KL) divergence 거리측정 방법 기반의 GMM-supervector SVM 커널, Bhattacharyya 거리측정 방법기반의 GMM-supervector SVM 커널 방식을 통한 화자인증 결과들과 비교하였다.

• 말소리와 음성과학
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• 제2권3호
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• pp.127-134
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• 2010

Additive noise and channel mismatch strongly degrade the performance of speaker verification systems, as they distort the features of speech. In this paper a histogram transformation technique is presented to improve the robustness of text-independent speaker verification systems. The technique transforms the features extracted from speech such that their histogram is conformed to a reference distribution. The effect of different standard deviations for the reference distribution is investigated. Experimental results indicate that, in channel mismatched environments, the proposed technique offers significant improvements over existing techniques. We also verify performance improvement of the proposed method using statistics.