• Title/Summary/Keyword: Clearance Design

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A Study on the Direction-Establishment of Church Building Design by the User Recognizing and Image-Evaluation (인지분석과 이미지평가에 의한 교회건축 방향설정에 관한 연구)

  • Choi, Sung-Yun;Kim, Hwa-Jeong;Han, Kyu-Young
    • Journal of the Korean Institute of Rural Architecture
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    • v.11 no.1
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    • pp.47-56
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    • 2009
  • According to the user recognizing, the propose of this study is to establish the systematic church-design and the plan of rational process. When the plan of church design is rational come out, the local community will be risen and there is the possibility which will raise the essential function of church construction and design. The results from the study are as follow. Firstly, the area of the front-window and the number of the external entrance are correlated with the accessibility of the building. Secondly, the height of a bell-tower is related with the feelings of a tediously and a intimate degree. Thirdly, the ground clearance of the whole surface is correlated with the church-character and the community formation of a local society.

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The Reliability-based Design Optimization for the Military Communication Equipment considering the Dimension Uncertainty (치수 불확실성이 고려된 군용 통신 장비의 신뢰성 기반 최적설계)

  • Park, Dae-Woong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.11
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    • pp.1051-1058
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    • 2011
  • The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the dimension was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

Optimal Design of a Squeeze Film Damper Using an Enhanced Genetic Algorithm

  • Ahn, Young-Kong;Kim, Young-Chan;Yang, Bo-Suk
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.1938-1948
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    • 2003
  • This paper represents that an enhanced genetic algorithm (EGA) is applied to optimal design of a squeeze film damper (SFD) to minimize the maximum transmitted load between the bearing and foundation in the operational speed range. A general genetic algorithm (GA) is well known as a useful global optimization technique for complex and nonlinear optimization problems. The EGA consists of the GA to optimize multi-modal functions and the simplex method to search intensively the candidate solutions by the GA for optimal solutions. The performance of the EGA with a benchmark function is compared to them by the IGA (Immune-Genetic Algorithm) and SQP (Sequential Quadratic Programming). The radius, length and radial clearance of the SFD are defined as the design parameters. The objective function is the minimization of a maximum transmitted load of a flexible rotor system with the nonlinear SFDs in the operating speed range. The effectiveness of the EGA for the optimal design of the SFD is discussed from a numerical example.

Development of the Practical and Adaptive Three steps Die for Sheet Metal Working(part 1) (Analysis of Production Part and Strip Process Layout Design)

  • Sim, Sung-Bo;Song, Young-Seok;Sung, Yul-Min
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.224-228
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    • 2000
  • The piercing and blanking of thin sheet metal working is specified division in press die design and making. In order to prevent the detects, the optimum design of the production part, strip process layout, die design, die making and try out etc. re necessary the analysis of effective factors. For example, theory and practice of metal shearing process and its phenomena, die structure, machine tool working for die making, die materials and its heat treatment, metal working in industrial and its know how etc. In this study, we analyzed whole of data base, theoretical back ground of metal working process, and then performed the progressive die tryout with the screw press. This study regards to the aim of small quantity of production part's press working. Part 1 of this study reveals with production part and strip process layout design.

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Optimum Design of Journal Bearing Using Simulated Annealing Method (Simulated Annealing법을 이용한 저널베어링의 최적설계)

  • 구형은;송진대;양보석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.121-126
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    • 2003
  • This paper describes the optimum design for journal bearing by using simulated annealing method. Simulated annealing algorithm is an optimum design method to calculate global and local optimum solution. Dynamic characteristics of a journal bearing are calculated by using finite difference method (FDM), and these values are used for the procedure of journal bearing optimization. The objective is to minimize the resonance response (Q factor) of the simple rotor system. Bearing clearance and length to diameter ratio are used as the design variables.

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Insulation coordination of 765 KV double circuit transmission line (765 KV 2 회선(回線) 송전선(送電線) 절연협조(絶緣協助))

  • Kim, Jeong-Boo;Min, Suk-Won;Lee, Dong-Il
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.774-777
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    • 1988
  • This paper covers the insulation coordination of 765 KV transmission line in Korea Electric Power Corporation. The design for the lightning, switching surge, and contamination was conducted to increase the reliability of 765 KV line. The authors have used the result of a limited Westinghouse ANACOM swiching surge study of the Korea Electric Corporation's 765 KV Expansion plan. The study investigated the switching surge overvoltage distribution and maximum switching overvoltage when relosing 765 KV lines. They used the technical data of the suspension insulator for the contamination design, which was available from a foreign insulator manufacture. From this paper, the authors find out that the contamination design dominates to determine the number of insulator and the SOV design dominates the air clearance in the tower. Afterwards the authors will confirm this design by Demonstration Test with Korea Electro-technology Research Institute.

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A study on minimization of fracture surface in fine blanking process using factorial analysis (요인분석법을 이용한 파인 블랭킹 공정의 파단면 최소화에 관한 연구)

  • Lee, Beom-Soon;Kim, Ok-Hwan
    • Design & Manufacturing
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    • v.15 no.1
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    • pp.41-47
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    • 2021
  • The Fine Blanking process is an effective precision shearing process that can obtain a smooth cutting surface and high product precision through a single blanking process. It is widely used in various manufacturing fields. However, shearing through this fine blanking process is only intended to minimize burrs, die rolls and fracture surfaces and does not completely remove them. Therefore, it is necessary to study the minimization of burrs, die rolls and fracture surfaces in the fine blanking process. In this study, a study was conducted on the relationship between the fracture surface and process conditions that occurred during product production using the fine blanking process. For this purpose, the shape of the V-ring indenter, the distance to the punch, and the pressure force, clearance, shear rate, and physical properties of the material were selected as process and design variables, and the relationship with the fracture surface according to each process and design condition was tested. It was analyzed through the Experimental Design Method.

Drug Interaction of Cimetidine and Cyclosporine in Human (정상지원자에서 Cimetidine과 Cyclosporine의 약물상호작용)

  • Choi, In;Choi, Jun Shik
    • Korean Journal of Clinical Pharmacy
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    • v.7 no.2
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    • pp.51-63
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    • 1997
  • The effect of cimetidine administration on the pharmacokinetic parameters of cyclosporine were determined in healthy voluteers. This study was performed in 10 volunteers of age ranged 22-48 years and body weight 48-62 kg. This study was performed with cross-over design. Mono cyclosporine and cyclosporine metabolites was extracted from whole blood analysed by fluororescence polarization immune assay (TDX-FLX, Abbott). After coadministration of cimetidine (300 mg) with cyclosporine (300 mg) orally, maximum concentration of mono cyclosporine was significantly increased $1221{\pm}143\;ng/ml\;to\;1562{\pm}184\;ng/ml$ (P<0.05), area under the time curve of cyclosporine (12 hr) also was significantly increased $7478{\pm}829\;ng/ml{\cdot}hr\;to\;9721{\pm}879\;ng/ml{\cdot}hr$ (P<0.05) and absolute baioavailability of cyclosporine was increased $50\pm5.6\%\;to\;57.6\pm6.1\%\;(P<0.05)$ compared to control group. The blood concentrations of cyclopsorine metabolites were significantly decrased (P<0.05) after coadministration of cimetidine. In cimetidine pretreated group, blood mono cyclosporine concentrations were increased significan시y $1220.0\pm203.00\;ng/ml\;to\;1510.0\pm204.00\;ng/ml$ compared with control group (P<0.05). In the mono cyclosporine pharmacokinetic parameter after oral administration absorption rate and maximum concentration were significantly higher in cimetidine coadministered and pretreated group than control group (P<0.05). The ratio of metabolites and mono cyclosporine concentrations was decreased significantly from $70.8\%\;in\;control\;to\;34.8\%$ in coadministration of cimetidine orally. As matter of facts these reults are considered to inhibition of cyclosporine hepatic metabolism and increasing of cyclosporine absorption rate in gastrointestinal tract because of maintaining cyclosporine stability in elevated gastric pH by cimetidine. We considered, it appeares that cimetidine increase bioavailability of cyclosporine by increasing oral absorption and by decreasing hepatic clearance. But the absorption and clearance of cyclosporine was highly variable individually, and therefore we consider that cyclosporine blood level monitoring would be essential in patients with cimetidine co-administration.

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Air Jet Effect on Performance Improvement of Non-Contact Type Seals for Oil Mist Lubrication Systems (공기분사가 오일미스트 윤활 시스템용 비접촉 시일의 성능 향상에 미치는 영향)

  • Na, Byeong-Cheol;Jeon, Gyeong-Jin;Han, Dong-Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9 s.180
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    • pp.2159-2166
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    • 2000
  • Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger

Trade Facilitation for E-Commerce Export Clearance

  • Ji-Soo Yi
    • Journal of Korea Trade
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    • v.27 no.3
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    • pp.179-198
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    • 2023
  • Purpose - There is a paucity of literature dealing with exporters' compliance issues in e-commerce exports. This study aims to fill this gap in the literature by exploring customs initiatives to facilitate the e-commerce exports of small and medium-sized enterprises (SMEs) in the changed compliance environment. The central question of this study was divided into five subquestions: first regarding the pros and cons of trade facilitation measures for Korean e-commerce export clearance; second and third questions about risk and compliance management for facilitation fourth about instruments, the changes in Korean SME compliance burden in e-commerce exports, and ways to improve trade facilitation for e-commerce exports. Design/methodology - This study adopts a qualitative approach using a case study method to understand the SME experience in Korean e-commerce export compliance procedures. A qualitative method was selected to answer research questions requiring an in-depth understanding of the regulatory procedures of customs administration and exporters' compliance burden. Because this study addresses the changing compliance environment for which statistical data is insufficient, a quantitative method is considered inappropriate. Based on the approach, data were collected using multiple sources, including an extensive literature review, interviews, and field observations. Thematic pattern matching was applied to interpret the data. Findings - This study examined ways to support SMEs in the changed e-commerce export compliance environment. Facilitation measures for e-commerce exports have contributed to SME access to global markets, simplifying export clearance procedures, and saving exporters' compliance costs. However, such instruments are limited in promoting SME compliance capabilities to cope with intensified competition and strengthened controls over foreign exporters in cross-border e-commerce. Therefore, this study highlights the importance of reshaping facilitation measures for e-commerce exports based on risk and compliance management theories to a system encouraging exporters' voluntary compliance. Originality/value - This study's academic significance derives from verifying the relationship between trade facilitation instruments and risk and compliance management procedures using an actual case in Korea. It is also of practical importance in navigating the directions for improving facilitation measures for e-commerce exports in a changed compliance environment.