• 한국기계가공학회지
• /
• 제14권1호
• /
• pp.70-77
• /
• 2015

This paper develops and evaluates a mechanical machining process which involves drilling on PVS material. According to the material, two treatment experiments were conducted, one involving drilling in a wet condition or using a lubricant and one involving drilling in a dry condition with no lubricant. Drilling in a dry condition showed better performance in terms of the cutting time than in the wet condition. Otherwise, the wet condition has several advantages. The lubricant influenced the burr diameter size and minimized the temperature on the surface of the work piece. During the wet condition drilling process, a smaller burr diameter size was noted as compared to the dry condition. The temperature showed a linear correlation with the drill bit size, where a least-square analysis provided an $R^2$valuewhichexceeded 0.95. The wet condition required more cutting time than the dry condition. In this condition, the water provides a lubrication effect. A thin layer between the cutting edges and the surface of the work piece is formed. The chip formation is affected by the drilling depth. The color on the tips of the chips was darker than in the initial condition. No correlation between the drilling depth and the bore roughness was noted, but the variation of the cutting speed or the RPM influenced the roughness of the bore. The optimum cutting speed ranged from 40 RPM to 45 RPM in the condition which provided the finest roughness surface.

• 한국의류산업학회지
• /
• 제10권5호
• /
• pp.668-675
• /
• 2008

The purpose of this study was to collect data of skin temperature and physiological responses which is useful for standardization of insulation measurement in various garments. And we investigated sex and season difference of physiological responses of 60's males and 60's females in hot and cold environment. Healthy ten 60's males and ten 60's females volunteered as subjects. The experiment was conducted three times; One for winter condition($5^{\circ}C$, 45%), another for summer condition($30^{\circ}C$, 65%) and the other for nude condition as control($30^{\circ}C$, 65%). The subjects were sitting for 1 hour with suitable ensemble on each experimental condition in climate chamber. We measured skin temperature, rectal temperature, heart rate, oxygen uptake, sweat rate, blood flow, blood pressure and subjective sensations. We found that skin temperature and most of physiological responses were higher in male subject, summer condition than in female subject, winter condition.

• Journal of applied mathematics & informatics
• /
• 제37권5_6호
• /
• pp.491-506
• /
• 2019

In this paper, we show the existence and uniqueness of solution to stochastic differential equations under weakened $H{\ddot{o}}lder$ condition and a weakened linear growth condition. Furthermore, the properties of their solutions investigated and estimate for the error between Picard iterations $x_n(t)$ and the unique solution x(t) of SDEs.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제16권1호
• /
• pp.1-11
• /
• 2009

The notion of a BCK-algebra with supremum (briefly, sBCK-algebra) is introduced, and several examples are given. Related properties are investigated. We show that every sBCK-algebra with an additional condition has the condition (S). The notion of a dry ideal of an sBCK-algebra is introduced. Conditions for an sBCK-algerba to be an spBCK-algebra are provided. We show that every sBCK-algebra satisfying additional condition is a semi-Brouwerian algebra.

• 지구물리와물리탐사
• /
• 제11권2호
• /
• pp.153-160
• /
• 2008

실제 매질에서 전파하는 파의 거동을 묘사하기 위하여 탄성파 모델링을 수행한다. 일반적으로 실제매질은 반무한 매질이나 컴퓨터를 이용한 수치모델링에서 반무한 매질을 표현하기는 쉽지 않다. 따라서, 유한한 크기의 모형을 가정하며, 이 경우 모형의 좌우 및 하부 경계는 가상의 경계이므로 이로부터 반사되는 인위적인 반사파들은 적절한 경계조건을 도입하여 제거되어야 한다. 최근 들어 등방성 매질 뿐 아니라 이방성 매질에 대한 연구가 증가하면서 이방성 매질에서의 경계를 적절히 표현해 줄 수 있는 방법이 필요하게 되었다. 본 연구에서는 등방성 매질의 탄성파 모델링에서 가장 많이 이용되는 스펀지 경계조건, Clayton과 Engquist가 제안한 흡수경계조건, Higdon의 흡수경계조건 세 방법을 이방성 매질에 적용할 수 있도록 변형한 후 다양한 포아송의 비를 갖는 모형에 적용함으로써 세 경계조건의 특성을 분석해 보았다. Clayton과 Engquist의 흡수경계조건은 등방성 매질에서 포아송의 비가 클 때 불안정한 모습을 보이는데, 이방성 매질에서도 역시 같은 결과를 보여주었다. 스펀지 경계조건은 등방성 매질과 이방성 매질에서 매우 좋은 결과를 보여주었지만, 컴퓨터 메모리나 계산시간을 고려하였을 때 비효율적이다. 이에 반해 Higdon이 제안한 경계조건은 필요로 하는 컴퓨터 메모리와 계산시간이 적을 뿐 아니라 큰 각도로 입사되는 파에 의해 발생하는 반사파까지 효과적으로 제거하였다. 따라서 포아송의 비가 비교적 크게 나타나는 이방성 매질에서는 계산상의 효율성 등을 고려할 때 Higdon의 흡수경계조건이 적합할 것으로 생각된다.

• Human Ecology Research
• /
• 제54권1호
• /
• pp.45-56
• /
• 2016

This study investigates: (1) children's proactive aggression according to age and the emotional condition of the counterpart child, (2) if children's intention attribution, emotional attribution (victim and perpetrator) and language ability influences proactive aggression according to age and the emotional condition of the counterpart child. The subjects were 68 3-year-old and 70 5-year-old children. Each child was individually interviewed with picture cards. Collected data were coded and analyzed in SPSS with frequencies, percentiles, means, standard deviations, repeated measures analysis of variance (ANOVA), t -tests, Pearson correlations and multiple linear regression. The results showed that 3-year-old children showed more proactive aggression and physical aggression than 5-year-old children. They showed more proactive aggression when counterpart child was in a happy condition than in a fear condition. Intention attribution, emotional attribution, and language ability partially affected a children's proactive aggression according to age and the emotional condition of the counterpart child. This study has practical implications for teachers in regards to children's proactive aggressive behavior at child care centers. Teachers use specific to develop advantages as the basis for developing aggression prevention programs that consider emotional and cognitive factors.

• 보건교육건강증진학회지
• /
• 제16권2호
• /
• pp.105-119
• /
• 1999

A human being's pursuit is that of a better quality of life and the disabled naturally want to do so. But challenged people's lives have not improved apace with the general development of our society as a whole. Specially, in a patriarchal society like Korea, challenged women are in a less favorable situation. Challenged women can enjoy more healthy and more happy life in a given condition. Thus, in this research, we closely examined the women's general characteristics, disabled characteristics, health condition(subjective health condition, experiences of diseases, stress value, etc), satisfaction value of life who have handicaps of limb or/and body. On the 17th of September through the 14th of October '98, a nation-wide retardation compaign was held and 200 people were served by telephone. Then we analysed primary factors on quality of life. As results, monthly income, how they think of their economic level, their subjective health condition, and the stress level that the success depends on self influenced quality of life.

• Journal of applied mathematics & informatics
• /
• 제9권1호
• /
• pp.101-124
• /
• 2002

The convergence rate of a numerical procedure barred on Schwarz Alternating Method (SAM) for solving elliptic boundary value problems (BVP's) depends on the selection of the interface conditions applied on the interior boundaries of the overlapping subdomains. It hee been observed that the Robin condition(mixed interface condition), controlled by a parameter, can optimize SAM's convergence rate. Since the convergence rate is very sensitive to the parameter, Tang[17] suggested another interface condition called over-determined interface condition. Based on the over-determined interface condition, we formulate the two-layer multi-parameterized SAM. For the SAM and the one-dimensional elliptic model BVP's, we determine analytically the optimal values of the parameters. For the two-dimensional elliptic BVP's , we also formulate the two-layer multi-parameterized SAM and suggest a choice of multi-parameter to produce good convergence rate .

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집E
• /
• pp.668-671
• /
• 2001

For the saving of energy consumption, it is necessary that the high efficient energy transfer machine. We found the optimum operating condition of screw water chiller during this performance test. The specifications of compressor for this performance test are as follows. Built-in volume ratio; Vi=2.4, using refrigerant; HCFC-22, nominal motor output; 60kW(80Hp). We found the test results on water cooled chiller standard test condition that the evaporating capacity is increased 8% maximum and 5.6% under same operating condition. and COP is increased 11 % max. and 8% under same operating condition with change of the evaporating inlet/outlet condition. For the results of these test, we can estimate the optimum operating condition of water cooled type screw chiller.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2004년도 International Conference Current Challenges and Advances in Environmental Health
• /
• pp.12-14
• /
• 2004

Objective to know about pollution of ventilated system in super market and hotel's air condition in Kunming. Methods to take out 28 ventilated system from super markets and hotels in Kunming in march 2004. To check dirt amount in pipelines and microorganism in dirt. Testing result is appraised under 'Public hygiene standard of ventilated system in air condition'. Results pollution problem exist in different degree in all the super markets and hotels that have been investigated. There is 32.14% which means 8 hotels and 1 super market, pollution is serious, The others (67.86%) is medium. Conclusion pollution problems exist in air condition system in all super markets and hotels of Kunming. Discussion aim at Kunming's special weather, and present condition of public ventilated system, discussing ways of management in hygiene of air condition system.