• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1761-1766
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• 2004

Recently, Plastic optical products are widely used. Injection molding process has advantages of low cost and high productivity. However, it remains a residual birefringence and residual stress by difference cooling. The present study focused on measuring birefringence in optical plastic parts using interference color pattern. The main idea of an analysis comes from chromatic aberration which is caused by difference light wavelengths. As a result, a complete system measuring the high order 2-D birefringence pattern was built. Further investigation is under way to improve the accuracy of birefringence measurement system by diode laser.

• 한국항만경제학회지
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• 제19권2호
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• pp.33-53
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• 2003

The purpose of this paper is to investigate the effectiveness of port investemnt which is one of the important elements for measuring the port efficiency by using congestion approach of DEA(Data Envelopment Analysis). Congestion is said to be present when increases in inputs result in input reductions. Congestion approach takes the forms of weak input disposability and strong input disposability. Empirical analysis by using congestion approach in this paper identified inefficiencies in the inputs including port investment, and indicated inefficient ports like the ports of Sokcho, Gunsan, Pohang, and Seoguipo which shows the large amount of slacks with congestion especially in terms of port investment. Therefore these ports should examine the reason about the inefficiency of port investment. The main policy implication based on the findings of this study is that The Ministry of Maritime Affairs & fisheries in Korea should introduce congestion approach when the amount of port investment to each port is decided.

• Industrial Engineering and Management Systems
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• 제13권2호
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• pp.210-220
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• 2014

This article describes a 2-in-1 methodology utilizing simulation optimization technique and Data Envelopment Analysis in measuring an accurate efficiency score. Given the high level of stochastic data in real environment, a novel methodology known as Data Collection Budget Allocation-Data Envelopment Analysis (DCBA-DEA) is developed. An example of the method application is shown in banking institutions. In addition to the novel approach presented, this article provides a new insight to the application domain of efficiency measurement as well as the way one conducts efficiency study.

• Journal of Power Electronics
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• 제17권4호
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• pp.963-971
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• 2017

Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.

• 대한임베디드공학회논문지
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• 제6권5호
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• pp.327-333
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• 2011

Intelligent robots are widely needed in various areas of industry from extremely dangerous environments to service tasks. For autonomous mobile robots, it is significant to move itself safely to a destination point, recognizing its surroundings. Advances in sensor technology and its applications are achieved in order to develop an intelligent robot. In this paper, a mobile robot with a path-finding algorithm is presented. The path-finding algorithm is the one that does not only find a path to designated destination and also recognizes obstacles on the way, calculating its distance. 10 ultrasonic sensor are mounted on the front and rear of the mobile robot to figure out its position. Specular reflection and wide viewing angle, which are inherent characteristics of ultrasonic waves, cause errors in measuring distance.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.43-50
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• 2022

Continuous development is the key of development issue in developing nations. Smart city measurement is prevalently carried through in the cities in which the nations have been classified as industrialized countries. In addition, cities in Europe becomes the models of smart city system. Smart city concept used in the cities in Europe applies six predominant features i.e. smart economic, smart mobility, smart environment, smart people, smart living, and smart governance. This paper focuses on figuring out city' development strategy in developing nations particularly Indonesia in regard with European Framework by way of Multi Expert Multi Criterion Decision Making (ME-MCDM). Recommendation is resulted from the tests using the data collected from one of the metropolis cities in Indonesia, whereby issuing recommendation must firstly implement smart education, secondly communication, thirdly smart government, and fourthly smart health, as well as simultaneously implement smart energy and smart mobility.

• 한국인터넷방송통신학회논문지
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• 제18권3호
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• pp.49-59
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• 2018

현재 여러 국가들은 스마트 그리드 시스템의 법적, 기술적, 비즈니스 측면에서 여러 문제점들이 발견되고 있음에도 불구하고 스마트 그리드 배치를 서두르고 있다. 스마트 그리드와 관련하여 중요한 문제는 스마트 미터기의 주된 성능을 그대로 유지하면서 미터 측정값들이 믿을 수 없는 이해집단들로부터 공격을 당하지 않도록 하는 것이다. 이러한 프라이버시 보호 문제는 하드웨어 제약사항, 보안 암호화 시스템과 보안 신호 처리와 같은 몇 가지 해결책들을 요구하고 있다. 본 연구에서는 이와 관련하여 현재 스마트 미터 프라이버시 보호 영역에서 주된 도전 문제가 되고 있는 미터 사용량 집계 암호화에 관한 하나의 접근방식을 제공한다. 개별 에너지 총 사용량에 관한 프라이버시 보호를 위해 개별 사용자 집계 함수에 잡음 가중치를 부여하는 방식을 나타낸다. 접근방식에서 준동형 암호화 성질을 충족하기 위해 잡음 가중치의 곱은 1이 된다. 단적으로 개별 에너지 사용자 집계를 알 수 없도록 하는데 있다. Diffid-Hellman 생성기를 적용하는 경우에 잡음 가중치 곱은 잡음 가중치 합으로 전환되고 가중치 합은 0이 된다. Diffid-Hellman 키 교환은 보통 512비트를 사용하기 때문에 아주 큰 키들을 사용하는 다른 Paillier 계통 암호화 방법들에 비해 보다 우수한 성능을 가진다.

• 복식
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• 제28권
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• pp.99-112
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• 1996

In this study I purpose a new approach to the study of Korean costume history which includes a statistical method used in the prac-tical measurement of excavated Po's and the analysis of their quantitative changes. In the framework used in this study I de-pend on the nineteen variables picked out from the typological and chronological analysis of excavated clothes. The interrelationship of the variables as well as the standard of each part and its deviation in other forms are may main concern. Other methods are also very useful in my thesis: Correlation analysis Regression analysis Discrimination analysis Cluster analysis Discrimination analysis Cluster analysis Factor analysis One way analysis of variance. The findings of my study can be summarized as follows: 1. Every type of po has a general tendency to have more broadened sleeves while it does not show any considerable changes in the total length and in the width of armholes. 2. In the Correlation analysis each part of Po's is handled separately accordign to its chronology and type. The Regreesion analysis makes it possible to provide the sizes of miss-ing parts in excavated clothes and the numeri-cal value of each part needed in the pattern making. 3. The Discrimination analysis of the Po's whose types are unknown leads to the con-clusion that Chongsam and Chikryong Po are classified into Chikryong Po whereas Hongui is classified into Jooui In addition I propose discriminational function by which the age classification is possible discovering the variables associated with time change. 4. Five items-Gerneral Park's clothes Taewongun's clothes and three others produced later for the purpose of preserving Korean costume are proved to be in a differ-ent group and hence analyzed separately in the visual grouping of changui which is done after the cluster analysis and the factor analysis. 5. The results of the one way analysis of variance reveal that there is a difference in each part from period: the back width the sleeve length the sleeve width thelean fig-ure the breasttie length the breasttie width outside quesset upper inside quesset lower outside neckband length insideneckband length etc.

• 한국항행학회논문지
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• 제16권4호
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• pp.619-626
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• 2012

단방향 Network RTK 방식은 최근 높아진 항체의 요구 정확도와 이동성을 동시에 충족할 수 있는 방식으로 고려되고 있다. 항체에 단방향 Network RTK 방식의 보정정보를 적용할 경우, 광역에서의 연속 항법을 위하여 다중 셀 기반의 Network RTK 방식이 필수적이다. 이 경우, 사용자가 셀 간 이동시 보정정보 생성에 사용되는 기준국 조합이 바뀌므로 보정정보의 불연속 값이 발생하는데, RTK 위치 결정을 위한 이중차분으로도 제거되지 않아 수평 13cm, 수직 48cm 수준의 오차가 야기됨을 확인하였다. 이러한 불연속 점을 해소하기 위하여 본 논문에서는 이종 셀 간 동일한 주(Master) 기준국을 사용하는 방안, 복수의 보정정보 수신 모듈을 설치하여 기존 위치를 기준으로 새로운 보정정보를 조정하는 방안, 이종 네트워크 간 미지정수 차이를 조정하는 세 가지 방법을 제시하였다. 세 방법 모두 셀 간 이동으로 인한 불연속 값을 효과적으로 제거되어 측정치의 1/4파장, 3cm수준으로 위치 오차가 감소함이 확인되었으나, 기준국 셀의 확장성, 사용자 장비 부담 경감 등을 고려할 때 셀간 미지정수를 조정하는 방식이 가장 바람직하다.

• 대한통합의학회지
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• 제2권2호
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• pp.79-88
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• 2014

Purpose: This study investigated the relationship between smartphone addiction propensities and compare muscle activity of the forearms and brain wave depend on the type of smartphone when inputting text messages. Method: We used an EMG to measure the change in muscle activity by attaching pads to the four muscles in both forearms of all 16 participants. We simultaneously conducted EEG measurements by observing the changes in alpha and beta waves recorded from electrode attached to both ears and the forehead of the participants. The participants had to input a given text using three different types of smartphones for ten minutes each. Result: The comparison of the EMG when inputting text involved a one way analysis of variance and the results showed that the iPad3 was highest for muscle activity followed by GALAXY Note2 and iPhone4. For EEG measurement, a one way analysis of variance was also used and the results showed iPhone4 was higest followed by GALAXY Note2 and finally iPad3 for EEG stress score. Conclusion: The results are thought to be used as reference data for smart phone users.