• 대한기계학회논문집A
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• 제29권5호
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• pp.726-733
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• 2005

A spherical surface referenced Shack-Hartmann method is studied for inspecting machining accuracy of large concave mirror This method is so strong to the vibration environment for using as an on-machine inspection system during polishing process of large optics comparing with the interferometry. The measuring uncertainty of the system is shown as less than p-v 150 m. On-machine measured surface profile data with this method is used for feed back control of the polishing time or depth to improve the surface profile accuracy of large concave mirror. Also, the spherical surface referenced Shack-Hartmann method is useful for measuring aspheric such as parabolic or hyperbolic surface profile, comparing that the interferomehy needs a special null lens, which is to be a reference and difficult to fabricate.

• 한국소음진동공학회논문집
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• 제18권3호
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• pp.356-360
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• 2008

This paper investigates the natural modes of moduled floating structure with module unit connector. As an example structure, a floating parking place($120m\;{\times}\;60m$) is considered. In the evaluation of natural modes, numerical equations are formulated by FEM(finite element method) and the natural modes are solved by the subspace iteration method. By comparing results for various sizes of module unit, the effect of unit size is investigated. By comparing results for various stiffness of module unit connector, the effect of stiffness of unit connector is also examined.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.124-127
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• 2002

Ceil embolisation technique has been used to treat the intracranial aneurysms. Microcoils inserted into the aneurysm sac induce the blood flow stagnation inside the aneurysm sac, which causes the thrombus formation and embolisation of aneurysm. Since the intraaneurysmal flow patterns affect the embolisation process, we want to measure the flow field for different locations of coil inside the aneurysm sac . Lateral aneurysm models are manufactured using rapid prototyping, and the velocity fields are measured using particle image velocitimeter. Distally blocked models showed less flow into the aneurysm sac comparing to proximally blocked models. Also blocking the neck of aneurysm showed better inflow blocking comparing to blocking the dome of aneurysm. These results suggest that distal neck should be the preferred locations of coil for aneurysm embolisation.

• 한국농공학회지
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• 제11권4호
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• pp.1803-1809
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• 1969

The newly designed mole drainage plower which is attached to tractor is tested for work capacity comparing with the pulling by man animal and winch. Besides. the effect of desalinization by the mole drainage in reclaimed tideland was observed. The results as obtained in this experiment are as follows: 1. The mole drainage plower of tractor attachment has higher work capacity by 3 to 5 times than that of winch 2. The suitable soil moisture content to carry out the layout of mole drains is from 21 to 25 percent. 3. The new design mole drainage plower requires th lowest cost as comparing with the other methods. 4. Carrying out the mole drainage in reclaimed tideland it is effective in desalinization from 2 to 3 times than the only use of irrigation water. 5. The reasonable depth and interval of mole drains may be 60cm and 3m respectively. 6. The desalinization by the mole drainage increases the yield of rice from 40 to 45 percent in reclaimed tideland.

• 한국보건간호학회지
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• 제28권3호
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• pp.471-483
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• 2014

Purpose: This study explored possible risk factors influencing the development of colorectal cancer by comparing life habits of colorectal cancer patients and healthy adults. Methods: The study was designed as a retrospective comparison survey study of the colorectal cancer patient group and healthy adult group. 107 colorectal cancer patients in a university hospital and 124 healthy adults were recruited from October 2011 to August 2012. Data were analyzed using descriptive statistics, ${\chi}^2$-test/t-test and logistic regression with the SPSS program. Results: Consumption of instant food products, lower stress management, burned meats and unhealthy eating habits were shown to be risk factors in development of colorectal cancer. Conclusion: Based on the results of this study comparing colorectal cancer patients and healthy adults, minimizing consumption of instant food products, development of healthy eating habits of consuming more vegetables, cooking meat slightly, and effective management of stress levels are recommended.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.299-302
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• 2005

Vehicle occupant exposure to air pollutants has been a subject of concern in recent years because of higher levels of air pollutants inside gasoline or diesel-using vehicle, comparing to the surrounding atmosphere. This study evaluated the potential exposure to respirable suspended particulate (RSP), nitrogen dioxide ($NO_2$) and volatile organic compounds (VOCs), comparing weekday (Monday and Thursday) and weekend (Saturday). Indoor mean concentrations of RSP inside vehicle were 51.2 $ug/m^3$ and 75.52 $ug/m^3$ in weekday and weekend, respectively. Measured indoor NO$_2$ concentrations were 14,8 ppb and 20.8 ppb, respectively. Benzene and toluene mean concentrations inside vehicle were 5.4${\pm}$2.4 ppb and 23.8${\pm}$33.8 ppb, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.509-511
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• 1994

Cycloconverters can be classified into two types by the main circuit configuration. One is the non- circulating current type required the dead time the other is circulating current type which has the circulating current reactors. The switching devices were highly stressed by the load voltages during dead time on non-circulating current type operation and the circulating currents on circulating current type operation. The overcome those problems, this paper proposes the switching patterns for the partial and the non circulation current type. The PWM methods, which are saw wave comparing method and load current integrating value comparing method, are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전력기술부문
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• pp.322-324
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• 2007

In this paper conceptual design methodologies of electric safety systems are proposed by micro and macro views. As a pre-study electric accidents of Korea were analyzed microscopically, which could be categorized into 11 types by the occurrence frequency. These types are caused by common problems, which are educations, live works, dealing by the public, and grounding systems. And the korean electric safety system is analyzed macroscopically according to stages of the system comparing with that of developed countries.

• 대한한의정보학회지
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• 제16권1호
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• pp.135-139
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• 2010

Quotations in "Dongeuibogam" are originated from books of Oriental Medicine. Those are exactly same with original books. However, some quotations are not in same comparing to original books. Authors are in concerns that the original sentences which are quoted in "Dongeuibogam" are how different and how similar or same, with comparing methods between them. As a result, we could find out original sentences in original books and we could make comparison between those and quotations of chapter of bone in "Wehyungpyun", "Dongeuibogam". Also we could get explanations of qoutations' accuracies.

• 경영과학
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• 제20권1호
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• pp.37-49
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• 2003

There is an increasing need to use mobile Internet as a research tool as wireless technology has been developing rapidly. However, little research has been conducted to confirm methodological validity of mobile Internet survey. This study examines the possibility of using mobile Internet as a survey tool by comparing survey results of mobile and stationary Internet surveys with the same questionnaire. The results were analyzed from both economic and theoretical perspectives. Both mobile and stationary Internet survey sites were implemented with supports from domestic mobile and stationary Internet portals and telecommunication companies. The results show that there exist several differences between two survey methods. First, many respondents who use mobile Internet gave up at the early stage. However, once people continued to respond, they answered the questions to the end. Second, means and standard deviations of mobile internet respondents were higher than that of stationary Internet. Third, the results of two survey methods were significantly different by comparing construct validity that includes both discriminant validity and convergent validity. Finally, this paper ends with implications and limitations of using mobile Internet as a survey tool.