• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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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.

• Proceedings of the KIEE Conference
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• 1985.07a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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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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• v.27 no.3
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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.

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.10a
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• pp.10-11
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• 2005

• Journal of Information Technology Services
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• v.13 no.3
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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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.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.905-910
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• 2008

In this paper, a circular motion table which is able to simulate movement of object is designed and the experiment of control system using circular motion table is presented. Circular motion table is consisted of three axes changed on length and of ball splines which keep vertical centre axis of circular plate. Variable length of three axes make circular plate incline as vertical centre axis is kept on vertical center axis of circular motion table. It is designed that control system drives three servo motor, that is, make change length of axis simultaneously or independently. And this paper presents example of flight simulation using circular motion table. it will contribute toward nurture expert manpower of aerospace/robotics to popularize circular motion table and make an experiment using it.