• International Journal of Reliability and Applications
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• v.5 no.1
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• pp.1-13
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• 2004

It is recently well recognized that the technique for the one-sided stress wave velocity measurement in structural materials provides measurement in structural materials provides valuable information on the state of the material such as quality, uniformity, location of cracked or damaged area. This technique is especially effective to measure velocities of longitudinal and Rayleigh waves when access to only one surface of structure is possible. However, one of problems for one-sided stress wave velocity measurement is to get consistent and reliable source for the generation of elastic wave. In this study, the laser based surface elastic wave was used to provide consistent and reliable source for the generation of elastic wave into the materials. The velocities of creeping wave and Rayleigh wave in materials were measured by the one-sided technique using laser based surface elastic wave. These wave velocities were compared with bulk wave velocities such as longitudinal wave and shear wave velocities to certify accuracy of measurement. In addition, the mechanical properties such as poisson's ratio and specific modulus(E/p) were calculated with the velocities of surface elastic waves.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.55-63
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• 2003

Conventional command-based communication services are rapidly substituted by multimedia web-based communication services at most recent times As the result, many valuable database and services that were developed by investing lots of human and material resources become to be useless Therefore in this paper we researched the methodologies and techniques for designing and implementing a multimedia web-based database system that made users easily access to database and services by updating the conventional command-based database services.

• Steel and Composite Structures
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• v.10 no.3
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• pp.281-295
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• 2010

An experimental and a non linear finite element investigation on the behavior of steel-concrete composite beams stiffened in hogging moment region with Carbon Fiber Reinforced Plastics (CFRP) sheets is presented in this paper. A total of five specimens were tested under two-point loads. Three of the composite beams included concrete slab while the other two beams had composite slabs. The stiffening was achieved by attaching CFRP sheets to the concrete surface at the position of negative bending moment. The suggested CFRP sheets arrangement enhanced the overall beam behavior and increased the composite beam capacity. Valuable parametric study was conducted using a three dimensional finite element model using ANSYS program. Both geometrical and material nonlinearity were included. The studied parameters included CFRP sheet arrangement, concrete strength and degree of shear connection.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.62-66
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• 2008

Machine parts subjected to fluctuating or cyclic loads induce repeated stresses that often result in failure by fatigue. In such cases, the fatigue failures unfortunately sometimes occur. These may arise from a lack of knowledge with regard to the design, fabrication and operation of the machines or structures. The failure analysis provides valuable information regarding the prevention of similar failures. Furthermore, this information will be useful to improve or to develop new products. Failure stress analysis is classified into X-ray fractography. X-ray fractography has the limited applications because of material crystal size, difficult measurement method, electrolytic polishing precision, and long test time. Therefore, this study proposed the new method to improve the measurement precision of plastic zone depth and test time using TRIZ.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.39-45
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• 2005

Numerical and visualization procedures are used in a finite difference grid to analyze and better understand the heat transfer in the MEMS based air micro-jet array (MIA) impingement cooling device. The Navier-Stokes (NS) equations with incompressible flow are solved using an implicit procedure. The temperature contour and velocity vector visualization diagrams are used for illustration. The computed temperature distribution at the bottom of the MIA is in good agreement with the experimental measurement data. The parameters are investigated to improve the efficiency of heat transfer in the MIA. The optimum configuration of the MIA is suggested. The present modeling explains the flow phenomenon and yields valuable information to understand the flow and heat transfer in MIA.

• Journal of The Korea Institute of Healthcare Architecture
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• v.6 no.10
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• pp.77-94
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• 2000

The purpose of this thesis is to lay groundwork for the development of emergency care system in metropolitan area. It compares the performance and outcome of the current system with foreign counterparts and investigates the changing aspects of future medical environment. Emergency medical system can be divided into two parts of both pre-hospital care, which refers to the emergency measures taken before arriving at a hospital, and hospital care that is given within a hospital. Pre-hospital care includes on-the-spot expedients, information system and delivery system, whereas hospital care is related to the classification and specialization of medical care facilities. This research focuses on the evaluation of the performance of a rescue party, which is part of pre-historical care system. As a result, it provides valuable material for the development of the emergency medical system in Seoul.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.11a
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• pp.54-58
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• 2007

The part of women was limited in a large family of the past and the benefit of a family was more valuable than the advantage of an individual. But social activity of the individual who is a member of the family is increased by the industrialization and rapid changes of society. As a result importance of the family is on the decrease in a society. All such phenomenons make new family types that we could not imagine at past and various life-style. This research proposes life-style of the near future and investigated by life-style stream process according to change members of the family with various documentary record. In conclusion, life-style of the near future is changed individualistic, rationalistic and material.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.34-37
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• 2008

The composite materials are widely used in the many applications of industry as well as aerospace field because of their high specific stiffness and strength which benefits the material and provides potential energy savings. However, composite materials also have a low property about external applied impact. In this paper, impact tests were conducted on different sample types(glass, carbon and kevlar composite) to obtain information such as absorbed energy and composite deformation using an instrumented impact test machine (DYNATUP 8250). 3 type samples were compared to experimental results. The data from impact test provided valuable information between the different type samples by wet lay up. This paper shows results of that kevlar composite has larger absorption energy and deformation than others.

• Journal for History of Mathematics
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• v.16 no.1
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• pp.45-62
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• 2003

The goals of a major reform effort are to enable us to educate informed citizens who are better able to function in our increasingly technological society. Discrete mathematics is an exciting and appropriate vehicle for working toward and achieving these goals. it is an excellent tool for improving reasoning and problem solving skills. Discrete mathematics has many practical applications that are useful for solving some of the problems of our society and that are meaningful to our students. Its problems make mathematics come alive for students, and help them see the relevance of mathematics th the real word. To build up the role of Discrete mathematics in the school, this study is to investigate various theories and curricula related to discrete mathematics, and to collect a great deal of valuable material that will help teachers introduce discrete mathematics in their classrooms. In conclusion. mathematics teachers will find the need and importance of why and how discrete mathematics can be introduced into their curricula by this study.

• Resources Recycling
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• v.27 no.4
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• pp.65-69
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• 2018

In solvent extraction, extraction isotherm represents the relation between the equilibrium concentration of metal in the aqueous and organic phase. McCabe-Thiele diagram on which extraction isotherm and operating line are constructed provides valuable information on the mass transfer operation. When the equilibrium constant of a solvent extraction reaction is known, the calculation method to obtain extraction isotherm was introduced. Kresmer equation by which the number of extraction stages can be calculated when the distribution coefficient is constant was introduced.