• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.631-637
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• 2005

This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

• The Journal of Information Technology
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• v.4 no.2
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• pp.117-127
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• 2001

A self-structured neural network algorithm that finds optimal fuzzy membership functions and nile base to fuzzy model is proposed and a fuzzy-neural network controller is designed to get more accurate position and velocity control of wheeled mobile robot. This procedure that is composed of three steps has its own unique process at each step. The elements of output term set are increased at first step and then the rule base Is varied according to increase of the elements. The adjusted controller is in competition with controller which doesn't include any increased elements. The adjusted controller will be removed if the control-law lost. Otherwise, the controller is replaced with the adjusted system. After finished regulation of output term set and rule base, searching for input membership functions is processed with constraints and fine tuning of output membership functions is done.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1582-1589
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• 1996

Rapid prototyping is a new prototyping technology which produces three dimensional part models directrly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Appaaratus(SLA) which is the most widely-used rapid prototyping system is introduced to achieve die/mold technology innovation. For the purpose, the prototyping technology using SLA is developed such that patterns of which shapes are quite complicated are successfully produced with high accuracy. Using these patterns, prototype die/molds are efficientrly manufactured; a turbocharger rotor, a fan and a wheel patterns, prototype die/molds are efficienterly manufactured ; a turbochager rotor, a fan and a wheel pattern are made, and the molds of the investment casting, the injection molding and the die casting are manufactured respectively. The casting products are produced using these molds and it turns out that these methods are quitre effective for manufacturing products of complicated geometry from the viewpoint of efficiency and productivity.

• Clean Technology
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• v.10 no.4
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• pp.189-194
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• 2004

The review of the present status of Korean industries and the establishment of strategic R&D agenda are necessary to improve the innovative technological capabilities of Korea to the top level of the world. Recently, Korean ministry of science and technology (MOST) has selected specific areas to develop national technological innovation system, and prepared national technology roadmap (NTRM). Korean ministry of environment (ME) also has prepared technology roadmap (TRM) to help efficient development of environmental science and technology. The development of eco-friendly process in NTRM and TRM was introduced and reviewed in this study. In addition, strength, weakness, opportunities, and threats (SWOT) analysis of technological capabilities of Korea was performed. The results propose the core role of industry, university, research institute, and government for the development of Korean environmental process technology.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.132-143
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• 2017

It is essential to obtain periodic sediment discharge data in a river in order to minimize problems that may arise from the erosion, transport, and deposition of sediment. However, it is difficult to estimate sediment discharge by the sediment discharge measurement plan in Korea at present, and empirical fomulas or numerical models are used to replace them. This paper has applied the K-DRUM model, a grid-based rainfall-runoff-sediment model, to estimate sediment discharge and ensure the continuity of the data in the watershed. Discharge and sediment load in 17 watersheds were estimated and the applicability of the model was analyzed through comparisons with measured data. For quantitative evaluation, NSE, PBIAS and RSR items were used, and discharge results reflected the tendency of rainfall and showed high statistical value. In case of sediment discharge, the soil erosion process of the watershed is physically well reflected. When the calibration was performed using the measure data, the applicability seems to be excellent in estimating the continuous sediment discharge data in the real watershed.

• Journal of Science and Technology Studies
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• v.8 no.1
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• pp.29-54
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• 2008

This is to review the reform of the governance for science and technology advanced by the Noh Moo Hyun government. The reform mainly included introducing the vice premiership for science and technology, strengthening the coordinative function of the National Science and Technology Committee over the public R&D budget and programs, and establishing the Office of Science and Technology Innovation under the vice premier for science and technology. The reform aims to improve not only the policy coordinative mechanism but policy discourse mechanism over the enhanced science and technology policy. This paper argues that Noh Moo Hyun Government's reform of the governance for science and technology was not successful. The reason is that the reform targeted mainly to improve the policy coordination among government departments concerning science and technology policy. But it was nearly neglected to make effective the policy discourse mechanism linking the state actors and societal actors.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.22-30
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• 2017

PL (Product Liability) refers to the legal responsibility of a manufacturer or seller for bodily injuries or property losses caused by product defects. Therefore, it is important for companies to construct a product liability response system that strategically manage and effectively adapt to product liability. A PL response system refers to companywide operations of PL prevention (PLP) measures, product safety (PS) measures, and PL defense (PLD) measures appropriate for a company's scale and environment. To establish an enterprise product liability response system, each essential component of corporations should be systematically operated and maintained considering the scale and characteristics of the corporations. Essential components of PL response system is Strategy, Organization, Training, Technology, Investment, and Awareness. Role of essential components is that companies need specific strategies to secure product safety and protect customers from product defects, and appropriate organizations must be composed for effective operation of such strategies. The objective of this paper seeks to examine the relationships among the essential components of the product liability response system and PL performance. PL performance consists of positive performance and negative performance. In particular, positive performance include increased efforts in product or process innovation such as strengthening research and development (R&D) to produce safer products without defects. In order to carry out this research we obtained 98 questionnaire of manufacturing company. A summary of the analyses is as follows: First, the awareness and technology among essential components affect significantly to the positive performance. Second, the awareness and strategy among essential components negative affect to the negative performance.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.175-187
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• 1999

The notion of productivity has been extended from the quantitative change of input factors to the efficiency change meaning efficient use of resources, and to the technical change meaning the qualitative improvement of input resources. In this way, the technical change is termed as total factor productivity in the individual businesses or the manufacturing industries. They should efficiently respond to the variations of economic environment and at the same time, have to make the efforts to improve productivity by increasing managerial efficiency and rasing the level of technology change for the continuous growth. Considering the growing importance of productivity, this study closely examines the factors influctuation on the productivity, fluctuation using total factor productivity in korean manufacturing industries. For the objective this study investigates the methods of measurement about total factor productivity, establishes the hypotheses based on the preceding research and finding. The results are obtained through the examination on the outcoms of regression analysis and related data. The results can be summarized as follows, First, in the progress of korean industrialization, the qualitative growth does not depend on the total factor productivity of the technical advance, and does not lead to the industry expansion. That is, the contribution of total factor productivity turns out to be relatively low. Second, it is necessary for the manufacturing industry to improve the level of technology and to emphasize the innovation of business, since the capital investment does not completely become fixed in the growth rate of productivity. Finally, continuous R&D investment should be made to increase total factor productivity. Namely, the regulation of industrial structure with an intensive technical development is essential and should be based on scientific and technical knowledge.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.432-437
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• 2013

The CO preferential oxidation reaction (PROX) has been done using Cu catalytic active species supported on some of mesoporous silica materials which can facilitate the diffusion of the reactants in order to prevent the poisoning of anode active materials by CO molecules during driving polymer electrolyte fuel cells (PEMFC) in this study. As a result when SBA-15 with large pore used as a support showed excellent CO oxidation activity, especially the activity increased in proportion to the amount of supported Cu. Ti components which was inserted to increase the degree of dispersion of Cu, contributed to improving the performance for CO oxidation at low-temperature. The degree of dispersion of Cu ingredients was the best in the catalyst inserted 20 mol-% Ti into the framework of SBA-15, and CO oxidation activity was also improved.

• Management & Information Systems Review
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• v.36 no.2
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• pp.93-111
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• 2017

This study aims to examine economic effects and success factors of ICT based growth engine industry for forth generation industrial revolution. KTRS(kibo Technology Rating System) provided by KIBO is used for an analysis of this study. Specifically, the economic effects of growth engine industy are classified with financial(productivity, growth rate, etc) and non-financial(R&D investment and employment) effects. Moreover, the impacts of KTRS factors including CEO capability, technology ability, commercialization and marketability on the economic effects are investigated. The result of this study would raise management issues on technology innovation and provide implications on industrial policies for ICT based growth engine industry.