• 한국세라믹학회지
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• 제41권12호
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• pp.873-879
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• 2004

In all major industries ranging from powder industries and advanced ceramics, to the food and pharmaceutical manufacture powder industries, the main production process is the spray dryers. In this paper, a systematic approach is used and six rules are obtained for the basis of the fuzzy model. A fuzzy model is based on the past behavior of the target system and expected to be able to reproduce the behavior of the target system. The output of the developed fuzzy model shows, graphically and statistically, a high level of face validity. Therefore, it is concluded that the developed fuzzy model mimics the actual process and can be considered, with confidence, as a reliable model to study, analyze, and improve the existing process.

• 대한기계학회논문집A
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• 제31권7호
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• pp.739-746
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• 2007

Recently, models in STL files are widely used in reverse engineering processes, CAD systems and analysis systems. However the models have poor geometric quality and include only triangles, so the models are not suitable for the finite element analysis. This paper presents a general method that generates finite element mesh from STL file models. Given triangular meshes, the method estimates triangles and makes clusters which consist of triangles. The clusters are merged by some geometric indices. After merging clusters, the method applies plane meshing algorithm, based on domain decomposition method, to each cluster and then the result plane mesh is projected into the original triangular set. Because the algorithm uses general methods to generate plane mesh, we can obtain both tri and quad meshes unlike previous researches. Some mechanical part models are used to show the validity of the proposed method.

• Asia pacific journal of information systems
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• 제10권3호
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• pp.17-40
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• 2000

This study aims at proposing a direction of improving the efficiency in Korean information technology(IT) industry. In the face of re-engineering which has been done in most industries, it is very important to assess the validity of their restructuring or M&A based on the future efficiency. At first, by using the DEA/WINDOW, we will evaluate how the 30 firms are efficient for outputting their performance with respect to the profit realization and market ability. Then, in order to propose the direction of the efficiency improvement and suitable restructuring strategy, we will clarify how the efficiency of IT firms depends on their firm size. Finally, we will analyze their 'economy of scale' and also reveal how their economy of scale depends on the firm size based on return-to-scale(RTS).

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 자동차부품 제작기술의 진보
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• pp.87-95
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• 1996

The stamping process consists of two stages : First, the blank is held by the blank holder and then it is further formed into the die cavity by punch stroke. In actual stamping process, the accurate prediction of binder wrap is an indispensable step in sheet metal forming analysis because the initial plastic buckling induced by improper die design is directly related with fatal defect at the final stage. In the present work, an approach including the gravity effect of blank material and proper consideration of contact and friction is proposed. Computations are carried out for some actual auto-body parts using 3D FEM code to investigate the validity of the proposed methodology. Comparisons with experimental results show that the suggested scheme can be effectively applied to the precise prediction of binder wrap for arbitrarily curved die faces in which gravity and contact effect must be taken into account.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.169-172
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• 1995

In optmizing cutting condition for face milling operation, tool wear is an important maching factor. For the purpose of establishing the relationship between various maching factor and tool wear, cutting tests have been performed. As a result, hardness and chemical composition of workpiece material, chemical compositition and grain size of cutting tool and cutting speed have been selected as machining factor. In addition, relationship between feed rate and workpiece hardness has been observed. Prior to utilizing cutting condition recommended by 'Machining Data Hardbook(MDH)' as a Knowledge base, an analysis for the validity has been provided. Based on this analysis, tool life criteria applied by MDH has been modifiied. Finaly, using MDH recommended data for neural network trainning, we can compensate the result form the trained neural network for optimizing cutting condition for some given workpice and cutting tool.

• 한국정밀공학회지
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• 제14권3호
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• pp.82-88
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• 1997

In this paper, the development of a precision CNC lathe prototype for mirror surface machining is presented. To obtain high precision machining accuracy, a hydrostatically supported precision spindle and a sliding guideway with turcite pad are adopted as the motion elements. The machining accuracy of the prototype machine, and the motional accuracy of its motion elements are tested and evaluated to confirm the validity of the application of these elements on the prototype. The hydrostatic spindle shows 0.09 .mu. m of rotational accuracy and the guideway shows about 0.8 .mu. m/170mm of horizontal straightness. The sur- face roughness of cupper and aluminium cylinder machined by the prototype machine with diamond tool are 0.07 .mu. m and 0.10 .mu. m Rmax respectively. From these results, it is verified that the prototype lathe is avail- able for high precision machining.

• 한국멀티미디어학회논문지
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• 제19권6호
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• pp.1014-1023
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• 2016

In this study, we presented a method for non-square Differential LBP operation that can well describe the micro pattern in the horizontal and vertical component. We proposed a way to represent a LBP operation with various direction components as well as the diagonal component. In order to verify the validity of the proposed operation, Differential LBP was investigated with respect to accuracy, sensitivity, and specificity for the classification of facial expression. In accuracy comparison proposed LBP operation obtains better results than Square LBP and LBP-CS operations. Also, Proposed Differential LBP gets better results than previous two methods in the sensitivity and specificity indicators 'Neutral', 'Happiness', 'Surprise', and 'Anger' and excellence Differential LBP was confirmed.

• 기술혁신학회지
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• 제1권3호
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• pp.338-350
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• 1998

Asian countries, ranging from China and Japan to Korea and Taiwan, differ in their industrial development stages to support the aerospace industry, and market access conditions. Despite these differences, all these countries target the aerospace industry as one of their future industries. The phenomenon challenges the conventional view that entry into the aerospace sector follows a gradual path from simple hanger repairs to license production, and to international collaboration. This paper reviews current status of the Asian aerospace with a dichotomy of the conventional promotion and Fast-Track promotion strategies. Analysis revealed that multiple entry points, in terms of technological level, exist in the aerospace industry, while the conventional thinking still holds validity. Then the paper presents potential obstacles and challenges these Asian countries would face in the promotion of the industry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.343-345
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• 2005

In the study, the noise involved on the active circuit is identified using correlation function. In order to figure out the unknown location of noise source, signals from each sections in the system are collected and the location is identified by a concept called "Noise Source SUI-face". Experiment is conducted to confirm the validity of the proposed method. Also a method to reduce and control the noise in the system signal by using Matrix Pencil Method is introduced. Experiment is attempted to prove that the total noise of system can be reduced by controlling the external noise.

• ETRI Journal
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• 제28권1호
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• pp.111-114
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• 2006

An alternative human interface enabling people with severe motor disabilities to control an assistive system is presented. Since this interface relies on the biosignals originating from the contraction of muscles on the face during particular movements, even individuals with a paralyzed limb can use it with ease. For real-world application, a dedicated hardware module employing a general-purpose digital signal processor was implemented and its validity tested on an electrically powered wheelchair. Furthermore, an additional attempt to reduce error rates to a minimum for stable operation was also made based on the entropy information inherent in the signals during the classification phase. In the experiments, most of the five participating subjects could control the target system at their own will, and thus it is found that the proposed interface can be considered a potential alternative for the interaction of the severely disabled with electronic systems.