• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집
• /
• pp.40-42
• /
• 2002

Electromigration is atomic diffusion driven by a momentum transfer from conducting electrons. With every new generation of intergrated circuits, interconnect line widths have been reduced and current densities in the interconnect have become higher. This leads to an increase in the threat to interconnect reliability due to electromigration. In this paper, we simulated stress evolution with changing temperature, duty factor(ratio of on time and pulse time), frequency under pulsed DC condition. As a result, we predict MTF(median time to failure) and found that exponent n is affected by changing temperature, duty factor.

• 소음진동
• /
• 제8권2호
• /
• pp.297-305
• /
• 1998

The finite element method is used for the study of the eigenvalue problems of partially fixed end beams with intermediate elastic supports. The elastic critical loads and natural frquencies of the beams are investigated by changing the numbers of elastic supports and their stiffness, and also by changing Kinney's fixity factor, $f_a$. The relationship between two eigenvalues is established by calculating the corresponding values of $(w/w_n)^2$ through changing $(P/P_{cr})$ values. The results of this study are as follows : (1) The elastic critical loads and natural frequencies of beams increase with increases in Kinney's fixity factor, $f_a$ and with the increased numbers of intermediate elastic supports. (2) The relationship between elastic critical loads and the natural frequencies of partially fixed end beams with intermediated elastic supports is $P/P_{cr} + (w/w_n)^2/ = 1$ without regard to Kinney's fixity factor, the stiffness of elastic supports, or the number of elastic supports.

• 에너지공학
• /
• 제22권3호
• /
• pp.283-286
• /
• 2013

전력사업자의 요청, 경제적인 요인 또는 기타 요인에 따라 기존 발전소의 설계개념 변경 없이 발전소의 전기출력을 증가 또는 감소시켜 발전소를 재설계하는 경우가 종종 있다. 이때 노심출력 및 전기출력을 변경시켜 재설계되는 발전소의 설비들의 가격을 예측할 경우, 시장에서 견적을 받을 환경이 아닐 경우에는 기존발전소 설비들의 가격에 비용보정계수(Cost Scaling Factor)를 적용하여 새로 설계되는 발전소 설비들에 비용들을 계산할 수 있다. 이에 미국의 DOE, EPRI, ABB, SWEC 기관들의 발전소 용량변경에 따른 비용보정계수를 검토하고, 그것을 국내 PWR 1000MWe, 1400MWe에 적용한 결과를 소개하고자 한다.

• 한국치위생학회지
• /
• 제7권4호
• /
• pp.395-403
• /
• 2007

The purpose of this study is to investigate the main factors that affect turnover of Dental Hygienists so that it leads to preventing high turnover and long-term service in their position. Data were obtained from 112 dental hygienists who are currently working for dental clinics from September 17th 2007 to October 16th 2007 via questionnaires. For this study, the demographic factors and unique characteristics of Dental Hygienists are considered as well as all the variables of statistic. The results derived from using SPSS 11.0 are as follows: 1. The average of job related factors is 2.55 point, the average of job satisfaction is 2.59 point, the average of salary related factor is 2.24 point and the average of changing their occupation is 2.85 point. 2. The difference between the factors related to age and changing their occupation shows the highest level on job related factors.(pM0.033) in the age between 26 and 30. 3. Dental Hygienists who are in their occupation for 6years to 9 years answer that salary would be the main reason to change their jobs. 4. For married dental hygienists, salary related factor is the main reason to make them change their occupation.(pM0.002)

• 한국디지털건축인테리어학회논문집
• /
• 제8권1호
• /
• pp.65-74
• /
• 2008

Light creates ambiance that affects our impression of space. Before the modern age, the role of light is a religious factor and a primitive state to see. In the modern space design, light is used to achieve the continuous transformation and translation of building's image. Ever-changing space is a flexible corresponding of space to its environment, caused by certain dynamic light. The space turn into some other thing from what it was before, or just changing its character. approaching men and society with different meanings. The purpose of this study is to explore the relation between light(natural and artificial) and ever-changing space through the case study. The impacts of light on ever-changing in today's space design can be summarized as follows. 1) Materialization of light in space design. Nowadays light becomes a form itself. The geometric properties of the space form playa secondary role as compared to the importance assigned to light. 2) Pixelization of space by a light effect. The impacts of digital technology on the space design have come through enhancing the 'pixelization' of the surface from which buildings are made their responsiveness and adaptability to changing needs. The surface with ever-changing lights that blur the boundary of space and expand the image of space.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
• /
• pp.220-222
• /
• 1998

This paper presents a method, which develops an ability of Zero-phase Overcurrent Relay. Zero-phase current is very useful factor of Fault decision in Protect Relaying system. Actually, the setting-point value of Designed Relay, using Zero-phase current, is fixed. So in the case of deciding fault, Fixed setting-point value is not suitable for changing Load. and cause errors in Distributions system. For solving this problem, This paper proposes the Changed setting point value Algorithm, which can be adaptive for changing Distributions system using Zero-phase current r.m.s. indexes. The results of simulation under Load changing and High impedance fault show that proposed algorithm is useful for changing Distributions system and decreasing errors.

• Communications for Statistical Applications and Methods
• /
• 제5권3호
• /
• pp.895-904
• /
• 1998

Two stage shrinkage testimator is a kind of adaptive estimators based on a test on an initial estimate of parameter. Since weighing factor plays an important roll in assessing the properties of testimator, its choice is extremely crucial in two stage testimation. Adke, Waikar and Schuurmann(1987) proposed a testimator for the mean of an exponential distribution defined with their own weighing factor. Two alternative testimators obtained using changed weighing factors are presented, and their Mean squared error(MSE) formulae are provided in this paper. Their properties are compared with those of existing one by means of MSE.

• 전기의세계
• /
• 제15권2호
• /
• pp.1-7
• /
• 1966

It is well known that the speed of induction motor can be controlled in wide range by changing the second exciting e.m.f. of rotor circuit, but that is well not practised because of its complicated system. In order to simplify such a system, the Kramer system of which silicon rectifier substitutes for synchronous converter has analyzed in this paper. The result of this investigation show that in this system, only the equivlent synchronous speed it changed by second exciting e.m.f., but the mechanical output power, torque and power factor is not changed, and that this system is able to compensate the regulated speed on account of the load changed.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제16권4호
• /
• pp.305-312
• /
• 2016

Purpose: The purpose of this study is to provide a sensitivity analysis of system reliability for recognizing effectiveness of changing of BD mode failures using reliability growth projection model based on NHPP. Methods: Crow extended reliability projection model (CERPM) is used to analyze the changing of two factors 1) the number of BD mode failures, 2) fix effectiveness factor (FEF) values. Results: The system reliability has increased in accordance with the number of BD mode failures and FEF values have increased. Conclusion: It is necessary to design failure modes and FEF values to supervise the reliability.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.859-863
• /
• 2004

Structural Dynamics Modification is very effective technique to improve structure's dynamic characteristics by adding or removing auxiliary structures, changing material property, changing shape of structure. In this research, using the surface grooving technique, shape of base structure was changed to improve its first natural frequency. Utilizing the result of sensitivity analysis, groove shape was formed gathering the many small embossing elements. For this process, Sensitivity Criterion Factor was introduced. To reduce its amount of calculation, the range of target area was restricted to their neighboring area and that result was very successful.