• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.401-408
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• 2003

A CAD program for metal bellows diaphragm was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and 5 circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution and fatigue life of bellows were estimated using commercial FEM code, NISAII. As a result, the metal bellows diaphragm was successfully designed by the CAD program. It is used to model a bellows geometry in pre-processor of FEM code. The FEM result shows that stress is dependent on straight line length, bellows diameter with same span, and fatigue life is also affected by design parameters.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.798-807
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• 2004

A testing system was developed to improve the reliability of printhead and several printheads were tested. We developed a thermally driven monolithic inkjet printhead comprising dome-shaped ink chambers, thin film nozzle guides, and omega-shaped heaters integrated on the top surface of each chamber. To perform a fatigue test of an inkjet printhead, the testing system automatically detects a heating failure using a Wheatstone bridge circuit. Various models were designed and tested to develop a more reliable printhead. Two design parameters of the width of reinforcing layer and heater were investigated in the test. Specially., the reinforcing layer was introduced to improve the fatigue life of printhead. The life-span of heater with a reinforcing layer was longer than that without a reinforcing layer. The wider the heater was, the longer the life of printhead was.

• Wind and Structures
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• v.36 no.2
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• pp.121-131
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• 2023

Aiming at the problem that fatigue characteristics of metal roof rely on local physical tests and lacks the cyclic load sequence matching with regional climate, this paper proposed a method of constructing the fatigue load spectrum based on integration of wind load model, measured data of long-span metal roof and climate statistical data. According to the turbulence characteristics of wind, the wind load model is established from the aspects of turbulence intensity, power spectral density and wind pressure coefficient. Considering the influence of roof configuration on wind pressure distribution, the parameters are modified through fusing the measured data with least squares method to approximate the actual wind pressure load of the roof system. Furthermore, with regards to the wind climate characteristics of building location, Weibull model is adopted to analyze the regional meteorological data to obtain the probability density distribution of wind velocity used for calculating wind load, so as to establish the cyclic wind load sequence with the attributes of regional climate and building configuration. Finally, taking a workshop's metal roof as an example, the wind load spectrum is constructed according to this method, and the fatigue simulation and residual life prediction are implemented based on the experimental data. The forecasting result is lightly higher than the design standards, consistent with general principles of its conservative safety design scale, which shows that the presented method is validated for the fatigue characteristics study and health assessment of metal roof.

• KIEAE Journal
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• v.1 no.1
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• pp.11-16
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• 2001

Concern about global environment has been increasing in recent years. Efforts to minimize the environmental impact to the globe as well as human beings have increased, especially in the late twentieth century. The study researches one of the solutions for the environmentally friendly building construction, which can contribute to sustaining the world environment. Assessment and proposals are made for high-rise apartments, one of the most popular construction types nowadays in Korea. Careful building design and construction for apartment buildings could reduce the environmental impact significantly without lowering standards of living. Since the volume of high-rise apartment construction is so great, a small improvement in each building will make a great contribution. Assessments are made over the life-span of apartment buildings. A tool has been made through references from western examples. mainly from BHEEAMs made in the United Kingdom. The components of the tool include passive design strategies, building materials. energy consumption during building operation, and management and maintenance. Co-relationship between buildings and ten environment in Korea is searched. Korean high-rise apartments are assessed with the tool and suggestions for sustainable development are made mainly for improvement of embodied energy of building materials and the life of buildings.

• Journal of The Korea Institute of Healthcare Architecture
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• v.8 no.1
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• pp.21-28
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• 2002

As hospitals change continuously and rapidly, the way of growth and change becomes another important factor in the design of a hospital. The hospitals are adapted for the continuous growth and change during their life span. But the hospitals built in 1970's and 80's have been expanded and reconstructed without any plan of growth and change. So, there is required to the architectural planning on the remodeling and modernization strategy of general hospitals. The purpose of this study is to provide the fundamental data for the reasonable design planning and the basic principles of the construction plan in the hospital remodeling. Thus, this study is to investigate and analyze the characteristics of hospital remodeling, the remodeling planning, and the scheduling process in terms of construction. As a result, this study would apply to design guideline for the remodeling of general hospitals.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.103-104
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• 2012

In the AC module system, mismatch problem between AC power and constant input power is occurred. To solve this problem, electrolytic capacitor is utilized for diminishing power pulsation in PV side. However, it has disadvantages of low life span and weak in temperature. Decoupling method has been studied to reduce the capacitance and replaces electrolytic capacitor to film capacitor. This paper proposes design method for decoupling circuit which bidirectional DC-DC converter using soft switching. Proposed system is verified by design optimization and simulation results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.60-66
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• 2011

In this paper, the computer simulation analyzed the effective plastic strain and temperature behaviors. The quantitative analyses which proposed the effective mold design of S/CAM shaft was executed. The parameters of forging shape that affected on the optimize conditions that was calculated with simple equation were investigated. it is expected that the developed analysis model and design technique would greatly contribute to the drum brake optimal design considering effective plastic strain and temperature affected behaviors. This development could save more than 20% of production cost and reduced failure rate to more than 30%. By improving the life span of mold from 15,000 to 25,000, financial difficulty of company imposed on a mold manufacture could be overcome.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1113-1118
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• 2008

In the hot forging process, The forging defects that are caused by metal were strain, temperate, and inclusion. In this paper, the computer simulation analyzed the effective plastic strain and temperature behaviors. The quantitative analyses which proposed the effective mold design of S/CAM shaft was executed. The parameters of forging shape that affected on the optimize conditions that was calculated with simple equation were investigated. it is expected that the developed analysis model and design technique would greatly contribute to the drum brake optimal design considering temperature affected and material behaviors. This development could save more than 20% of production cost and reduced failure rate to more than 30%. By improving the life span of mold from 15,000 to 25,000, financial difficulty of company imposed on a mold manufacture could be overcome.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.20-31
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• 2005

The contents of mobile phones are rapidly appended and the structures are being changed substantially. Most of the problems with mobile phones are related with the vibrations and the displacements of PCB boards. In this study, the vibration magnitudes of the boards by impulses on the case are analyzed with the variations of the selected design parameters. The result shows that the extensive suppression of the vibrations are feasible by the proper selection of the design parameters. Also the suggested relationships between the parameter selections and the magnitudes of vibrations can be applied to establish a database for improved stability of the mobile phone structure which is a critical concern considering the short life span of the mobile phone models.

• The Journal of Industrial Distribution & Business
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• v.8 no.2
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• pp.11-20
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• 2017

Purpose - The elderly do not want to know what they want and what happiness is, and have no interest in their society. Thus, many studies have been made to investigate real-life situations and to find a solution. Further studies are needed to investigate the effect of the elderly's dating upon happiness. This study investigated the effects of the elderly's dating upon life satisfaction. Research design, data, and methodology - After coding, SPSS Win18.0 was used. The study was investigated as follows. The subjects were 530 elderly of 3 cities in Chungnam who live without children. A total of 512 questionnaire responses were used after we excluded 18 questionnaire because of incomplete responses. Results - The elderly's date value accounted for 3.22 of 5 in full. In this study, the interviewees (82.3%) said normal or higher level to be satisfied with the date. Conclusions - With the extended life span of the elderly, their chances to retain or make new partners have increased. Considering this trend, social workers and others in senior centers should give health services to the elderly to consult and give educational programs to be free from prejudice and conservative attitudes. Most of the elderly had desire to date but thought that with prejudice and bias.