• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1996.11a
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• pp.37-42
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• 1996

The assessment of catastrophic accidents such as BLEVE, vapor cloud explosion, and toxic material releases in the chemical process industries(CPI) shall be carried out according to the Requirement of PSM/SMS enforced by Korea Government Agencies, but reasonable models are not proposed for the practical application. The traditional models, TNT Equivalency Model, are well-known and helpful for the assessment of vapor cloud explosion. However, the estimated-damage-area using the traditional model has much more deviations comparing to the real damage caused by vapor cloud explosion suffered before. These are why an expert system for the assessment of vapor cloud explosion has been developed, which is based on theoretical, statistical and experimental data, and it would be helpful for CPI to evaluate the damage-area in case of vapor cloud explosion.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.24-33
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• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider / tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data zone were better for those of the laser-textured zone. It was also found that durability of head-disk interface (HDI)decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.291-292
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• 2002

Using a low viscosity synthetic traction oil and a low viscosity mineral oil with nearly equal viscosity grade of ISO VG 32, the effect of kind of oil on the fatigue life of bearing steel rollers was examined. A pair of rollers finished the contact surfaces to a mirror-like condition were driven under rolling with sliding conditions of s = -3.2% and a maximum Hertzian stress in the range of $P_H=2.8GPa{\sim}4.0GPa$ was applied in point contact condition. As a result of experiments, the fatigue life with a mineral oil was longer than that with a traction oil under higher stress conditions above $P_H=3.4GPa$. Based on the numerical calculation results of the thermal EHL which simulates the present experiment, the authors discuss the reason why such a difference in the fatigue life comes out.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.65-71
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• 2008

This paper presents a transient heat transfer analysis of a drum brake shape. The transient heat transfer analysis of automotive drum brakes with frictional contact is performed by using the finite element method. The drum brake type studied in the page is the internally expanding one in which two shoes fitted externally with frictional material are forced outward against surface a rotating drum on the wheel unit. In this case, the braking power is produced by the friction force between a drum and a lining, and is converted into heat. The brake drum has constant material properties. The air inside the drum has temperature-dependent thermal conductivity and enthalpy. Radiation effects are ignored. The result explains the reason why hair crack and cause of drum failure occur. The temperature of drum is in proportion to the drum thickness and nonlinear changes at every points of drum. It's necessary for the decrease of the drum temperature to make the air inside drum flow.

• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.235-245
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• 1998

This survey was carried out to investigate the beverage consumption pattern. The Questionnaire, which consists of preference, quantity of daily consumption, selection, consumption of traditional beverages and so on, was distributed to elementary, middle and high school students and Home Economics teachers. Compared with teachers, students prefer soft drinks to coffee and tea. The factor considered as important appeared taste when they choose beverages. The reasons why they drink beverage were its being tasty and their heavy thirst. Among traditional beverages, sikhae was consumed most frequently at home. More than 50% of respondents answered that they had experiences of drinking whachae, soochungkwa, citron tea and ginger tea.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1134-1141
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• 2011

Costs have long since become a major issue in railway system analysis, attention is not limited to the acquisition costs alone, but encompasses all costs involved in the use and disposal of the systems. Concepts such as Life Cycle Cost(LCC), Costs Of Ownership(COO), or Total Ownership Cost(TOC) are more and more frequent in any document dealing with system analysis. Most of railway projects have applied this LCC Model to evaluate effectiveness of system acquisition cost. But these action of LCC model does not applied all the rest of system life cycle period due to the differences of its responsibility. This is why a study has been undertaken by the operation party to harmonize the most important aspects of the LCC model. This study focused on these and other objectives for introduction of method and needs for an action plan for maintenance actions involved relevant cost allocation.

• Journal of Hospice and Palliative Care
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• v.19 no.1
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• pp.5-10
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• 2016

Purpose: This study reviewed what the location of death (LOD) means as an outcome and how to use LOD to assess end-of-life (EOL) care. This study also examined the reason why LOD is significant for the quality of EOL care. Methods: A literature review was performed, using LODs and home deaths as outcomes in the field of EOL care, and analyzed the findings associated with key fields in regards to LOD. Results: Palliative care research used LOD, in particular, hospital death (versus home death) as a significant outcome when examining cost savings, quality of life care, and patient and family preferences. Based on substantial evidence from previous research, home hospice or continuous palliative care in non-hospital settings (i.e. homes, nursing homes) have been designed and available for dying patients in developed countries. Conclusion: The LOD delivers practical significance as an outcome for diverse reasons. In-depth examination on LOD in South Korea is needed despite limitations to interpretation of its meaning in the country.

• The Mathematical Education
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• v.55 no.2
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• pp.233-249
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• 2016

In this study, we extracted the background meaning of the condition that four points lie on a circle, analyzed textbooks critically and proposed the orientation to improve the content in the textbook. As results, the condition has a realistic background meaning which is 'mathematical modeling of finding a fair location'. The condition has a mathematical background meanings which are 'a first complex situation distinguished from two points and three points', 'the condition described in the perspective of side and angle in order to overcome the disadvantages of the perpendicular bisectors context' and 'being possible to transfer more than five points'. However it is difficult to understand the reason why the condition is on four points in the current textbook. In addition, it is difficult to recognize the connectivity of a circumcenter of triangle. To overcome these problems, we proposed five orientations to improve the content in the textbook.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.23-35
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• 2015

When people stands near someone's mobile device, it can easily be seen by others. To rephrase this, attackers use human psychology to earn personal information or credit information or other. People are exposed by social engineering attacks. It is certain that we need more than just recommendation for the security to avoid social engineering attacks. This is why I proposed this paper. In this paper, I proposed an authentication technique using NFC and Hash function to stand against social engineering attack. Proposed technique result is showing that it could prevent shoulder surfing, touch event information, spyware attack using screen capture and smudge attack which relies on detecting the oily smudges left behind by user's fingers. Besides smart phone, IPad, Galaxy tab, Galaxy note and more mobile devices has released and releasing. And also, these mobile devices usage rate is increasing widely. We need to attend these matters and study in depth.

• The Journal of Korean Medical History
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• v.15 no.2
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• pp.11-20
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• 2002

In "EuiMoonBubRyool" chapter 4, Yuchang criticized previous doctors since "damaged by wet in autumn" written in "Somun" must be corrected as "damaged by dry in autumn". The reason why the sentence must be corrected is that dry and damp are different atmosphere. He tried to explain with changes of season and the rapid pulse in autumn is said to be a contraindiction in "Naekyung" and it supports Autumn dry theory. He criticized previous doctors about many incorrect points of dry disease throu호 various aspects. Criticism on Dongwon's treatment, Dangye's medical theory and not having a treatment, and Mujungsoon's treatment and etc. are the examples. Symtoms and treatment of Dry disease that Yuchang commented helped in deepening the contents and widening the general understanding of the disease.