• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.296-301
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• 2005

This paper describes the kinematics, dynamics and control of a 6-DOF shaking table with a bell crank structure, which converts the direction of reciprocating movements. In this shaking table, the bell crank mechanism is used to reduce the amount of space needed to install the shaking table and create horizontal displacement of the platform. In kinematics, joint design is performed using $Gr{\ddot{u}}bler's$ formula. The inverse kinematics of the shaking table is discussed. The derivation of the Jacobian matrix is presented to evaluate singularity conditions. Considering the maximum stroke of the hydraulic actuator, collision between links and singularity, workspace is computed. In dynamics, computations are based on the Newton-Euler formulation. To derive parallel algorithms, each of the contact forces is decomposed into one acting in the direction of the leg and the other acting in the plane orthogonal to the direction of the leg. Applying the Newton-Euler approach, the solution of inverse dynamics is almost completely parallel. Only one of the steps-the application of the Newton-Euler equations to the platform-must be performed on one single processor. Finally, the efficient control scheme is proposed for the tracking control of the motion platform.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.976-984
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• 2009

This study proposes a simple method that uses a simple mass-spring model to predict the natural frequency of a soil-pile-structure system in sandy soil. This model includes a pair of matrixes, i.e., a mass matrix and a stiffness matrix. The mass matrix is comprised of the masses of the pile and superstructure, and the stiffness matrix is comprised of the stiffness of the pile and the spring coefficients between the pile and soil. The key issue in the evaluation of the natural frequency of a soil-pile system is the determination of the spring coefficient between the pile and soil. To determine the reasonable spring coefficient, subgrade reaction modulus, nonlinear p-y curves and elastic modulus of the soil were utilized. The location of the spring was also varied with consideration of the infinite depth of the pile. The natural frequencies calculated by using the mass-spring model were compared with those obtained from 1-g shaking table model pile tests. The comparison showed that the calculated natural frequencies match well with the results of the 1-g shaking table tests within the range of computational error when the three springs, whose coefficients were calculated using Reese's(1974) subgrade reaction modulus and Yang's (2009) dynamic p-y backbone curves, were located above the infinite depth of the pile.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.1
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• pp.19-43
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• 2007

The purpose of this study is to distinguish industrial clusters in Korea. Based on I/O table in 2000, coefficient matrix was calculated and factor analysis was performed on the matrix. Among 38 derived industrial clusters, 5 of them were unreported clusters, which were indistinguishable. Once these 38 industrial clusters were differentiated according to I/O table, final results of clusters were produced as I/O table was converted into KSIC (Korean Standard Industry Code). Since existing studies on industrial cluster have been focused on qualitative methods such as case studies and interviews, it is expected that this study could contribute to carry out more systematic and efficient methodology.

• Advances in nano research
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• v.16 no.4
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• pp.365-374
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• 2024

This study delves into the significant impact of integrating nanomaterials, specifically carbon and graphene nanoparticles, into the polymer matrix of aluminum alloy 356, utilizing the vortex casting technique, with the aim of improving the mechanical properties of table tennis equipment. Athletes and their coaching teams have long been on a quest for high-performance sports gear, recognizing its pivotal role in unlocking the full potential of players. The dedication of engineers to craft designs, select materials with precision, and uphold stringent testing standards reflects the commitment to meeting the demands of the sporting world. Yet, to remain at the forefront, sports engineering must continually align with contemporary technologies, and nanotechnology has emerged as a transformative force in this regard. This study not only underscores the meticulous efforts in material integration but also highlights the remarkable strides made possible by nanotechnology. Aluminum nanocomposites, particularly, showcase a groundbreaking fusion of exceptional strength and reduced weight, marking a notable achievement in sports equipment innovation. The research outcomes are compelling, revealing a substantial enhancement in the mechanical performance of the sports structures under scrutiny. This promising development hints at a potential paradigm shift in the manufacturing of sports equipment, promising a new era of elevated athlete performance and enhanced safety during the rigors of physical education training. This study stands as a testament to the tangible impact of nanotechnology on the ever-evolving landscape of sports equipment.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1487-1490
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• 2005

This study proposes a controller with the techniqu e of voltage -compensated driver for producing grayscaled pictures on passive matrix organic light emitting diodes (PMOLEDs) panels; especially, the controller overcomes the problem of luminance nonuniformity on displaying pictures. Because the controller is a voltage type driver, the output impedance of the driver is much less than that of the current-type driver. Hence, the controller provides a better electron-optical response than those of traditional current drivers. An area compensated look-up table (ACLUT) is designed in data feeding paths for removing luminance non-uniformity; thus, the proposed controller provides nearly 95% luminance uniformity.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.11
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• pp.421-429
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• 1985

With the rapid increase of contingency cases due to complication of power system, the reduction of computation time in contingency analysis has become more significant than ever before. This paper deals with the development of a fast contingency analysis algorithm by using a matrix decomposition method. The proposed matrix decomposition method of contingency analysis yields an accurate solution by using the original triangular factor table. An outstanding feature of this method is of no need of factor table modification for network changes due to contingency outages. The proposed method is also applicable to multiple contingency analysis withremarkable reduction of computation time. The algorithm has been tested for a number of single and multiple contigencies in 17-bus and 50-bus systems. The numerical results show its applicability to practical power systems.

• Journal of Korean Society for Quality Management
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• v.21 no.1
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• pp.199-213
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• 1993

The function-cost matrix table is not constant, but can be changed by many factors including equipment capacity, level of production technique, fluctuation of production volume, and the continuous development of products. Such changes would give the VE analysists additional work burden. By using computer. in this study, much of the time and effort of the function evaluation could be saved, and the efficiency of the analysis could also be enhanced. The application of the function evaluation data of R Company, as a case analysis, to the function evaluation computer program developed in this study resulted in the faster management of function-cost matrix table and function evaluation.

• Korea Trade Review
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• v.47 no.3
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• pp.75-92
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• 2022

This study aims to analyze the International trade network of Water transport service using Social Network Analysis for defining the status of Korean Water transport industry. This study use World Input-Output Table of Asian Development Bank from 2000 to 2020 and build the International trade matrix of Water transport service from that. Therefore, this study analyze Out-degree centrality, In-degree centrality and betweenness centrality of Korea and other main countries in the matrix of World Water transport industry. As a result, Korea rank above 10th in the all centralities and the total output also rank 8th in the world, therefore, this study show the importance of Korean Water transport industry in the world. However, Singapore has the highest centrality in the world, even though China has the largest Total output among 63 countries.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.10
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• pp.73-80
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• 1995

In this paper, a synthesis tool using matrix operations for designing multi-level Reed Muller circuits is described which has been named as MRM (Multi-level Reed Muller Minimizer). The synthesis method which uses matrix operations has advantages in effectively minimizing chip area, delay optimization and fault detection capability. However, it uses only truth-table type maps for inputs, synthesizing only small circuits. To overcome the weakness, our method accepts two-level description of a logic function. Since the number of cubes in the two-level description is small, the input matrix becomes small and large circuits can be synthesized. To convert two-level representations into multi-level ones, different input patterns are extracted to make a map which can be fed to the matrix operation procedure. Experimental results show better performance than previous methods. The matrix operation method presented in this paper is new to the society of Reed Muller circuits synthesis and provides solid mathematical foundations.

• Science of Emotion and Sensibility
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• v.5 no.2
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• pp.63-72
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• 2002

In order to examine universal design, 1 have developed two analytical methodologies based on 3P(point) task analysis: structured task analysis and task matrix analysis. I also extracted nine universal design items, namely (1) adjustment, (2) redundancy, (3) specification and function transparency, (4) feedback and (5) error tolerance, (6) effective acquisition of information, (7) ease of understanding and judgment, (8) comfortable operation, and (9) continuity of information and operation. Structured task analysis is used to uncover problems in each of the tasks constituting a job for each functionally challenged condition of users, and solutions to the extracted problems are examined in terms of the above-mentioned nine universal design items. Task matrix analysis calls for the production of a table for each task in a job. In each table, nine items form the columns, and the horizontal rows list all disability types. Then, solutions are formulated for each cell formed by the intersecting columns and rows. Using these two analysis methods, 1 have conducted a verification experiment for the universal design of a public bus. The results of the research have enabled me to propose various ,solutions from a system-based perspective, instead of coming up with the superficial and isolated solutions which are normally produced when conventional analytical methods are used.