• Journal of information and communication convergence engineering
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• 제7권2호
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• pp.231-234
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• 2009

Speckle noise reduction for power Doppler ventricle coherent image for restoration and enhancement using Fast Wavelet Transform with multi-thresholding and multi-filtering on the each subbands is presented. Fast Wavelet Transform divides into low frequency component image to high frequency component image to be multi-resolved. Speckle noise is located on high frequency component in multi-resolution image mainly. A Doppler ventricle image is transformed and inversed with separated threshold function and filtering from low to high resolved images for restoration to utilize visualization for ventricle diagnosis. The experimental result shows that the proposed method has better performance in comparison with the conventional method.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2001년도 추계학술발표대회 논문집 제20권 2호
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• pp.85-88
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• 2001

Line spectrum pair(LSP) 계수는 양자화 오류에 강하고. 선형 릴간에 효율적이며, 필터의 안정성 판정이 용이하므로 LPC를 대신하여 음성 부호화에 널리 사용되고 있다. 일반적으로 LSP 계수간에는 일정한 상관관계가 나타나고, 이 특성을 이용하면 LSP 계수의 부호량을 줄일 수 있는 가능성이 있나. 본 논문에서는 LSP 계수를 압축하기 위해 principal component analysis(PCA)를 사용한 방법을 제안한다. 제안된 방법에서는 LSP 계수를 Karhunen-Loeve(KL) 변환해 에너지가 집중되는 고유치(eigenvalue)와 고유벡터(eigenvector)를 찾고 값을 양자화 한다. 성능 평가를 위해 2.4kbps MELP(mixed excitation linear prediction)와 8kbps QCELP(qualcumn code excited linear prediction) 음성 부호화기를 사용해 결과 값을 비교했고, 압축률이 증가하는 것을 확인했다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제3권1호
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• pp.13-40
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• 2003

The seasonal adjustment is an essential process in analyzing the time series of economy and business. One of the powerful adjustment methods is X11-ARIMA Model which is popularly used in Korea. This method was delivered from Canada. However, this model has been developed to be appropriate for Canadian and American environment. Therefore, we need to review whether the X11-ARIMA Model could be used properly in Korea. In this study, we have applied the method to the annual sales of refrigerator sales in A electronic company. We appreciated the adjustment by result analyzing the time series components such as seasonal component, trend-cycle component, and irregular component, with the proposed method. Additionally, in order to improve the result of seasonal adjusted time series, we suggest the demand forecasting method base on autocorrelation and seasonality with the X11-ARIMA PROC.

• 한국전자통신학회논문지
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• 제9권5호
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• pp.575-582
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• 2014

본 논문은 LCD TV의 다양한 기술 중 어떤 것을 자체개발 하고, 어떤 것을 외부로부터 조달하여야 할 것인지를 결정할 수 있는 프레임웍을 제공하고, 이를 검정하였다. AHP를 이용하여 분석한 결과, 중요한 기술로는 Scaler chip, LCD panel, MPEG decoder, Video decoder 등의 순으로 나타났으며, 이들 상위 부품들은 삼성전자에서 직접 자체 생산이 이루어지고 있는 중요한 핵심부품으로 밝혀짐에 따라 본 논문의 타당성이 검정되었다고 할 수 있겠다. 본 논문을 통해 기업이 자체 개발해야만 하는 핵심부품을 선정하는데 도움을 줄 수 있을 것으로 기대된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.65-68
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• 2001

In the vector control methods of induction motor, the stator current is divided into the flux and torque component current. By controlling these components respectively, the methods control independently flux and torque as in the DC motor and improve the control effects. To apply the vector control methods, the position of the rotor current is identified. The indirect vector control use the parameters of the machine to identify the position of rotor flux. But due to the temperature rise during machine operation, the variation of rotor resistance degrades the vector control. To solve the problem, the q-axis is aligned to reference frame without phase difference by comparing the real flux component with the reference flux component. Then to compensate the slip, PI controller is used. The proposed method keeps a constant slip by compensating the gain of direct slip frequency when the rotor resistance of induction motor varies. To prove the validations of the proposed algorithm in the paper, computer simulations is executed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.102-103
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• 2007

The electrical characteristics of high power LIGBT implemented by CMOS process are described and compared with those of high voltage LDMOSFET with the same device dimensions. LIGBT has exhibited approximately 8 times superior current drive capability than LDMOSFET. The proposed p+/n+ anode structure resulted in the significant increase of on-state breakdown voltage of LIGBT. Therefore, LIGBT suggested in this paper is one of the promising candidate for smart power IC applications.

• 한국정보시스템학회지:정보시스템연구
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• 제9권1호
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• pp.61-86
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• 2000

CALS(Commerce At Light Speed) which originated in the early 1980's in the military sector is now an integral component in our global strategy to further heighten competitiveness. Through integration and streamlining of production, distribution, technical information and management, CALS will certainly lead the world out of these economically challenging times and into new global prosperity. However, not much effort have been focused on the development and diffusion issues of component technologies such as ERP/SCM(Enterprise Resourses Planning/supply Chain Management), PDM(Product Data Management), and BPR(Business Process Reengineering) related with the CALS in electronic industry. Therefore, the purpose of this study is to analyze the advancing status and to present suggestions for the development of the CALS in electronic industry. In order to achieve the purpose, the case study has been conducted using the questionaries on the end-users and the interviews on the managers in the CALS area. The case study cover 57 users of the CALS for the three outstanding electronics(L, S, and D Electronics) in Korea. The questionaries include five success measures and eleven diffusion factors for the component technologies such as ERP/SCM, PDM, and BPR. In summary, the CALS will serve as the bases for exciting corporated innovations and the common business framework which facilitates the realization of Virtual Enterprise and Electronic Commerce in the 21st century.

• 대한본초학회지
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• 제25권3호
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• pp.61-64
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• 2010

Objctive：To clarify the criterion, the characteristic of varaious age of ginseng radix cultivated in Korea and China were studied. Method：The surface of the transverse section of the specimen was made into a slid by the Paraffin Section method, and then dyed by Safranine Malachite Green method. The samples were observed at the power of 400 by an optic microscope(Olympus, Japan). The component and flavor of ginseng radix were analyzed by TLC(Thinlayer Chromatography) and electronic nose(FOX3000, France). Result：Ginseng radix according to the growing district and various age were comparative analyzed by optic microscope, TLC and electronic nose. The results were as followings. 1. The external form of Korean ginseng is longer and brightness then Chinese ginseng. 2. The internal form of Korean and Chinese ginseng are similar to each other. 3. The component of Korean and Chinese ginseng in TLC are similar to each other. 4. The fragrance of Korean and Chinese ginseng are clearly different. Conclusion：The results in this study demonstrate that morphology and component of Korean ginseng are similar to Chinese, on the other hand, fragrance of Korean and Chinese ginseng are different.

• 한국전기전자재료학회논문지
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• 제27권6호
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• pp.343-349
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• 2014

It is summarized that potential causes of performance degradations and failure mechanisms of crystalline silicon photovoltaic (PV) modules installed in Middle East area. In addition, we also reviewed current PV module qualification test (IEC 61215) and the methods for detection of wear-out fault. The failure of PV modules in the extreme environmental conditions such as deserts is mainly due to high temperature, humidity, and dust storms. In particular, cementation phenomenon caused by combination of sand and moisture leads to rapid degradation in the performance of PV modules. In order to evaluate and guarantee the long term reliability of PV modules, specific qualification tests such as sand dust test, salt mist test and potential induce degradation test considering operating environment of PV module should be carried out.

• 전기학회논문지
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• 제66권5호
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• pp.778-785
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• 2017

This paper presents a control method for reducing the distortion of the grid current at a grid-connected three-level neutral point clamped (NPC) inverter. The grid current is distorted from the 5th and 7th harmonic components in the stationary frame current also the 6th harmonic component in the synchronous frame current. In this paper, the 6th harmonic component on synchronous frame is controlled by using all-pass filters (APFs) and proportional integral (PI) controllers for distortion of the grid side. When transformed the 6th harmonic component is controlled, the 5th and 7th harmonic components are reduced. The validity of the proposed control method is verified by simulation and experiment results using a 25kW three-level NPC inverter.