• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (B)
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• pp.432-434
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• 2000

본 논문은 IJG(Independent JPEG Group) JPEG 부호기의 처리 과정중 color table 과 context 버퍼를 이용한 color conversion과 downsampling 방법에 대해 소개한다. IJG JPEG은 전처리 과정에서 context buffer 사용함으로써 각 컴포넌트(RGB)에 대한 color conversion과 downsampling을 효과적으로 수행한다. 또한 각 컴포넌트(RGB)에 대한 부동 소수점 연산의 처리 결과를 미리 계산하여 color table에 저장함으로써 color converter에서 이를 참조, 색차 변환 계산에 적용하도록 하여 처리 속도를 향상 시키고 있다. 이에 본 논문에서는 IJG JPEG의 부호화 과정에서 사용되는 context 버퍼의 구조와 필요성 그리고 color table의 구조와 효과에 대하여 소개한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1985년도 하계학술회의논문집
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• pp.249-253
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• 1985

본 논문은 후술할 다출력 스위칭 회로의 최소성 기준(Criteria of Minimality)에 의한 최소의 다출력 스위칭 회로를 설계하는 데 목적을 두고 있다. 이에는 단일 출력 스위칭 함수에 적용된 바 있는 Direction of Adjacency Table 방법이 다소 변경되어 다출력 스위칭 회로에 적용되었다. 이르 위하여 기존의 Direction of Adjacency Table을 다출력 함수의 최소화에 적합하도록 변경한 Extended Direction of Adjacency Table이 구성된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.734-738
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• 1997

In this study, we developed the indexing table opering by pneumatic actuation. We doubled the torque of index table by using specialy desingned air pipe and two pistons. And by locating two pistons We perform several tests and this results is written below.

• Korean Journal of Mathematics
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• 제27권3호
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• pp.723-734
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• 2019

We study the negative trinomial table T' of $(x^2+x+1)^{-n}$ and its t/u-slope diagonals for any t, u > 0. We investigate recurrence formula of the t/u-slope diagonal sums of T' and find interrelationships with t/u-slope diagonal sums of the trinomial table T.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2005년도 추계 학술발표대회 논문집
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• pp.10-11
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• 2005

• 한국IT서비스학회지
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• 제13권3호
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• pp.165-181
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• 2014

This study proposes the accurate labor inducement coefficient (employment inducement coefficient/hiring inducement coefficient) of Korea software industry by analyzing the inter-industry relation using the modified inter-industry table. To rewrite the inter-industry table of Korea, some previous studies related to the inter-industry analysis were reviewed and the key problems were identified. First, in the current inter-industry table published by the Bank of Korea, the output of software industry includes not only the pure software related output but also the output of non-software section due to the misclassification of the industry. This causes the output to become bigger than the actual output of software industry. Therefore, if the inter-industry table is not modified, the labor inducement coefficient would be overestimated too much. Second, during rewriting the inter-industry table, the output is changing. The inter-industry table is the table in the form of rows and columns, which records the transactions of goods and services among industries which are required to continue the activities of each industry. Accordingly, if only an output of a specific industry is changed, the reliability of the table would be degraded because the table is prepared based on the relations with other industries. This possibly causes the labor inducement coefficient to be over or underestimated. This study tries to correct these problems to get the more accurate labor inducement coefficient of the software industry. First, to get the output of the pure software section only, the data from the Korea Electronics Association (KEA) was used in the inter-industry table. Second, to prevent the difference in the outputs during rewriting the inter-industry table, the difference between the output in the current inter-industry table and the output from KEA data was identified and then it was defined as the non-software section output for the analysis. The followings are the labor inducement coefficient obtained when the output is divided into the pure software section (package software, and IT service) and non-software section. As of 2011, the employment inducement coefficients of pure software section, package software section and IT service of Korea were 8.616, 13.998, and 7.773 respectively while the labor inducement coefficients of pure software section, package software section and IT service of Korea were 7.979, 13.332, and 7.083, respectively.

• 한국기계가공학회지
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• 제13권5호
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• pp.107-115
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• 2014

Highly functional mill turrets have been developed and continuously improved to shorten the manufacturing time and enable multiple uses. Among these, a mill turret with B-axis rotary table was developed. The B-axis rotary table should be evaluated for structural integrity. Moreover, its worm and worm gear for transmitting power should be able to endure fatigue damage. Therefore, this article presents a structural analysis of this type of B-axis rotary table and confirms its static stability by comparing the stress results to the allowable stress levels. Next, the dynamic stability of the rotary table was investigated via a mode analysis and a harmonic analysis in a range determined by the results of a modal analysis. Finally, a worm gear set, the main part that drives the rotary table, is analyzed for fatigue and to estimate its lifetime. The results of the fatigue analysis allowed a prediction of the life of the worm gear set. The analytical results show that the B-axis rotary table has good structural integrity.

• 한국정밀공학회지
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• 제17권12호
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• pp.137-144
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• 2000

In order to achieve systematical method for improving motion accuracy of hydrostatic table, an algorithm using finite element method is proposed in this paper. Quantification of averaging effect of oil film on motion error is performed theoretically by analysis on the relationship between spacial frequency of rail form error and motion error of table. Influences of film stiffness and pocket size on the motion error of table are also analyzed theoretically. Validity of the algorithm is verified experimentally from the test on the motion error of table with three types of rail which have different form profile. Experimental results show that the algorithm is very effective to analyze theoretically the motion error of hydrostatic table.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.556-560
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• 2007

In this paper, the research results for the improvement of tracking performance of a hydraulic shaking table are presented. A servo-hydraulic shaking table is not only highly nonlinear but also has a lot of time delay. In addition, the shaking table, which consists of multi axial hydraulic actuators, is a MIMO system coupled by kinematics and dynamics of each other's actuators. And it is demanded for the shaking table to track arbitrary trajectories up to high frequency even at the extreme situations such as substantial external loads and large disturbances. For this purpose, an iterative feed-forward control based on the inverse of a measured frequency response function is used for the shaking table. To solve the dynamic coupling, a pressure feedback control as numerical damping is used. It is shown through numerical simulations that the tracking performance of shaking table is improved up to 100Hz.

• 한국산학기술학회논문지
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• 제9권4호
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• pp.905-910
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• 2008

본 논문은 운동 물체에 대한 시뮬레이션 할 수 있는 원판형 모션테이블 제작과 제어 실험 시스템을 제시하였다. 원판형 모션테이블은 3개의 길이가 변하는 축과 중심점을 유지하는 축으로 이루어져 있으며, 원판의 자세 변화에 따른 중심점은 중심축 상에 항상 놓이도록 설계 되어 있다. 제어 시스템은 원판형 모션테이블의 서보모터 3개를 제어함으로써 원판의 자세를 바꿀 수 있도록 설계 되었다. 또한 본 원판형 모션테이블을 이용한 비행제어 시물레이션을 예로 제시하였다. 이러한 소형 모션테이블의 보급과 이를 이용한 실험 교육은 우리나라의 항공우주, 로봇분야의 인력양성에 기여할 것이다.