• 대한전기학회논문지:전력기술부문A
• /
• 제48권10호
• /
• pp.1198-1205
• /
• 1999

This study is focused on the reliability evaluation for distribution system based on deterministic evaluation technique. Average failure rates, average outage time, and average annual outage time of electrical parts and load points are calculated through network reduction method and failure mode & effective analysis method. And reliability indices of distribution system are calculated. Finally, by employing analytic hierarchy process method, unique index which evaluates and improves the distribution system is calculated. As a result, finding weak points and expansion schedule of the system is possible. The usefulness of this method is verified by applying it to the Inchon International Airport.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.220-223
• /
• 2000

In this study for the development of a 3D pattern mill, we designed its layout which has high stiffness and low-weight structure. We calculated the load of each axis component when 3D pattern mill is under the worst cutting conditions. On base of the calculations, we determined the size of its structure and selected main components of the machine. Also, using FEM we analyzed the layout design of 3D pattern mill to reduce the wcight of structure and increase stiffness of it. According to the load position and direction, shapes and values of the deformation and the stress distributions are calculated, also we calculated the natural frequencies and mode shapes in order ta modify and redesign the weak parts

• 품질경영학회지
• /
• 제34권3호
• /
• pp.1-18
• /
• 2006

CMMI(Capability Maturity Model Integration) has been recognized as a critical method to validate the competitiveness of software development organization since its introduction. CMMI imposes additional requirements on the software development organization which has been established and certified to the ISO 9001 quality management system. This paper reviews the similarities and differences between CMMI and ISO 9001. This paper also examines what ate required to deploy the CMMI on the aircraft software development organization which has been certified to ISO 9001. The results of this study will help software development organization to provide the direction for implementing CMMI. Some suggestions are presented to identify and strengthen the weak portion of the software process quality management system.

• 한국기계가공학회지
• /
• 제19권2호
• /
• pp.75-80
• /
• 2020

In this study, we designed car frames for collision analysis using carbon fiber reinforced polymer (CFRP) as the lighter composite material. The impact conditions were 100 percent frontal impact, 40 percent frontal impact, and 90 degrees side impact. The impact analysis measured the maximum stress at velocities of 20km/h and 40km/h for each condition and evaluated the vulnerable points in the car frame. Additional supports have been designed both to improve the weak points in existing vehicle frames, and to be taken into account when new parts are assembled. Our impact analysis compared the results of maximum stress on the car frame with and without the support.

• 산업기술연구
• /
• 제21권A호
• /
• pp.17-26
• /
• 2001

The fatigue strength of SM55C has significantly decreased by 83% compared with atmosphere where distilled exists due to strong erosive action of acid fog. The reason is inferred in a way that strong acid erosive material such as acid fog act and give rise to multi-site crack on the surface. Several fatigue clacks occurred under the acid fog repeat the process of division and unification on the surface and form a long non-propagating crack throughout the circumference of experimented steel. However, in the depth, many parts do not show much trace of unification, and the depth is not as big as the one of normal crack shape. 10% of $CaCl_2$ causes strong erosive reaction to material. Then eventually make the life of fatigue shooter. On the other hand, 20% of $CaCl_2$ beings about oxidized material organic crack closing due to weak erosive reaction.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 춘계학술대회 논문집
• /
• pp.274-278
• /
• 2012

Vertical pumps are structurally weak in terms of vibration because of installed heavy motor on top of the pumps in form of cantilever. So high vibration on top of the pumps can occur with low vibration in the bottom. These vibration problems experienced very frequently. Majority of studies have been related to the unbalance of rotating parts or structural resonance. In this paper, we introduce an unusual case, vibration variation caused by VPF(Vane Passing Frequency) according to water level.

• 한국정밀공학회지
• /
• 제20권2호
• /
• pp.58-65
• /
• 2003

The conventional forming process such as squeeze casting or die casting for fabricating metal matrix composites products have a disadvantage such as non homogenous distribution of reinforcement, weak bonding between matrix and reinforcement and cost increase in parts fabrication. Thixoforming process has been accepted as a new method for fabricating the net shaped metal matrix composites with lightweight and wear resistance. In this paper, the effect of volume fraction and reinforcement sizes on mechanical properties in cylinder liner part of metal matrix composites has been investigated with processes parameters such as pressure and velocity. Moreover, the methods to obtain the thixoforged composites cylinder liner with high quality has been proposed. To evaluate the composites cylinder linear fabricated at the conditions proposed in this study, mechanical properties of fabricated composites cylinder linear were compared with those of commercial composites cylinder linear.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.336-340
• /
• 2014

The noise and vibration have been evaluated by using the finite element model in the vehicle developing stage. The sound pressure of the vehicle compartment is predicted by the acoustic cavity model coupled with the body structure. In general, the structural model has been focused to study in the improvement of the noise. It is not easy to treat the structural model, instead the acoustic cavity model is relatively simple and aids in root cause analysis of vibro-acoustic issues. Therefore, the acoustic transfer function of the cavity is more efficient for finding out the main contribution parts of the vehicle booming noise. And examples about the run-up booming noise demonstrate the validity of the AFT analysis for improving the vibro-acoustic sensitivity.

• 대한안전경영과학회지
• /
• 제15권1호
• /
• pp.177-182
• /
• 2013

More and more medium and small enterprises do business across the world according to generalization of online shopping mall such as eBay and Amazon. But high export and import transportation cost make weak the price competitive power of medium and small enterprises products. Then this paper deals with the development of new business model which can reduce the transportation cost for global logistics through efficiently overcoming the constraints as length, size, and weight of product. We explain this model with application for company which export the automobile parts. We can expect the transportation cost reduction by 50%.

• 한국공작기계학회논문집
• /
• 제17권4호
• /
• pp.119-125
• /
• 2008

A new type of swivel unit is suggested in order to complement weak points of the existing. This new type of Swivel unit is developed by adopting a spring type cable which has elasticity and restoring force. To minimize the troubles in the process of manufacturing during operating the new type system, strength analysis and the check of interference between parts are accomplished with CATIA. The check of rotating performance is also carried out to determine the diameter and length of spring type cable by SimDesigner motion analysis. Swivel unit used in the robot spot welding is developed with spring type cable and its usefulness in the industrial field is verified through experiments. This system has been registered for patent.