• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.2021-2028
• /
• 2010

Rail human factors research has grown rapidly in both quantity and quality of output over the past few years. Human factors, also, still plays a significant part in many railway accidents. In this paper we review categorized performance shaping factors of human errors associated with railway accidents within and out of the country. This paper deals with the selection of the important performance shaping factors under accident management situations in railway for use in the assessment of human errors. The purpose of this study is to classify which human error would be selected for accident analysis. Therefore, the classification of human errors suggested in this study may be useful to enhance the Korean railway system safety.

• Proceedings of the Korean Society for Rock Mechanics Conference
• /
• 2000.09a
• /
• pp.211-222
• /
• 2000

The design values of rock socketed pile related with properties of rock mass are not clearly established. However, the drilled shafts socketed in rock are widely used as the foundation of large scaled structure. In this study, the characteristics of behavior of rock socketed pile is researched, and the properties of interface between pile and rock considering soil-structure interaction are evaluated for numerical modeling of rock socketed pile based on the previous researches. Based on the properties of interface and rock mass, the behaviors of rock socketed piles are numerically modeled and compared with field measurement. To verify the numerical analysis, a micro pile socketed in rock is modeled and the results of numerical analysis are compared with field measurement. The numerical results show a good agreement with field measured data, especially in terms of load transfer characteristics.

• Tunnel and Underground Space
• /
• v.10 no.3
• /
• pp.457-468
• /
• 2000

The design values of rock socketed pile related with properties of rock mass are not clearly established. However, the drilled shafts socketed in rock are widely used as the foundation of large scaled structure. In this study, the characteristics of behavior of rock socketed pile is researched, and the properties of interface between pile and rock considering soil-structure interaction are evaluated for numerical modeling of rock socketed pile based on the previous researches. Based on the properties of interface and rock mass, the behaviors of rock socketed piles are numerically modeled and compared with field measurement. To verify the numerical analysis, a micro pile socketed in rock is modeled and the results of numerical analysis are compared with field measurement. The numerical results show a good agreement with field measured data, especially in terms of load transfer characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.04a
• /
• pp.600-605
• /
• 2012

In this paper, the acoustic performance of a shipboard large-sized room unit is studied. The room unit is a kind of rectangular absorptive chamber with a partition whose surface absorptive material with fabric skin is attached to. The room unit has one inlet and three outlet. At the inlet, a plane damper is installed to control the flow rate. The acoustic performance of a prototype room unit is measured using a HVAC mock-up. It is shown that its insertion loss is comparable with that of a commercially-used room unit but the developed room unit generates flow noise higher than the other one. The major source of flow noise is analyzed by NADS-R, the noise analysis program for room unit. Cone-shaped dampers are proposed to be used as the damper of a room unit to reduce flow noise. It is shown that the cone-shaped damper decrease flow noise remarkably.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.5
• /
• pp.468-473
• /
• 2012

In this paper, the acoustic performance of a shipboard large-sized room unit is studied. The room unit is a kind of rectangular absorptive chamber with a partition whose surface absorptive material with fabric skin is attached to. The room unit has one inlet and three outlets. At the inlet, a plane damper is installed to control the flow rate. The acoustic performance of a prototype room unit is measured using a HVAC mock-up. It is shown that its insertion loss is comparable with that of a commercially-used room unit but the developed room unit generates flow noise higher than the other one. The major source of flow noise is analyzed by NADS-R, the noise analysis program for room unit. Cone-shaped dampers are proposed to be used as the damper of a room unit to reduce flow noise. It is shown that the cone-shaped damper decrease flow noise remarkably.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.8
• /
• pp.21-29
• /
• 2003

This paper describes a research work on the development of computer-aided design system for deep drawing & ironing of a high pressure vessel. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories, handbook, experimental results and empirical knowledge of field experts. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM software, DEFORM and ANSYS, to form a useful package. It is composed of five main modules, which are calculation of product thickness, input, production feasibility check, process planning, and autofrettage process modules and two submodules, which are folding check and process variable verification submodules. Programs for the system have been written in AutoLISP on the AutoCAD 2000 using personal computer. The developed system makes it possible to design and manufacture large high pressure vessel requiring D.D.I. process more efficiently.

• Journal of the Korean Society of Safety
• /
• v.21 no.6 s.78
• /
• pp.7-13
• /
• 2006

A transient heat transfer and thermal stress analysis for a brake drum of commercial vehicles have been performed by ANSYS code in the cases of single braking and the repeated braking condition. The temperature and thermal stress distributions in the brake drum under various braking conditions were obtained using a two-dimensional axisymmetric model. In case of deceleration of 0.3G with an initial vehicle speed of 60km/h, the maximum temperature in the drum was $87.6^{\circ}C$ after braking application. The maximum stress of 78.7MPa in the drum occurred at the intersection between the flange and hat under a condition in which repeated 15 cycles braking with an initial vehicle speed of 60km/h and a deceleration of 0.3G is applied to according to KS R1129. The maximum stress value is much lower than the yield strength of drum material(FC250).

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.6
• /
• pp.88-96
• /
• 2006

The objective of this research works is to develop back panel dies of PDP TV with a large size. In order to design the geometry of the dies and an initial size of blank optimally, the finite element analysis has been carried out using AUTOFORM V4.2. The conner radius of the upper trimming area and the distance from the outer line of the blank holder to the outer line of the blank have been selected as design parameters to remove the wrinkling of the trimming area. The results of the analyses have been shown that a feasible product without wrinkles and skid lines can be obtained when the conner radius ranges from 6mm to 8mm and the distance lines in the range of 40-60mm. From the proposed design of the dies and an initial blank size, the final die set of the back panel has been successfully manufactured.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.219.1-219.1
• /
• 2014

전자소자 산업의 미세화 및 대형화에 따라 플라즈마 밀도, 전위, 온도, 균일도 등 과 같은 플라즈마 특성을 제어하는 것은 차세대 플라즈마 장치 개발에 있어 매우 중요한 요소라고 할 수 있다. 특히, 급격한 소자의 미세화에 따라 플라즈마 공정을 통해 발생할 수 있는 damage는 큰 issue가 되어 왔고, 많은 연구자들은 이를 해결하기 위해서 다각적인 노력을 진행해 왔다. 그중 높은 전자 온도는 높은 전자 에너지에 의해 공정 중 소자를 손상 시키는 주된 원인이라고 보고되고 있으며, 이에 대한 제어기술은 매우 중요하다고 할 수 있다. 본 연구에서는 서로 다른 두 개의 내/외측으로 나뉘어진 나선형 모양의 ICP 안테나를 이용 하여 연구를 진행하였다. 내측의 안테나에는 2 MHz를 연결 하였으며, 외측의 안테나에는 13.56 MHz를 연결 하였으며, 내/외측 안테나에 각각 pulse mode로 입력전력을 인가해 줌으로써 플라즈마의 특성을 관찰하였다. Pulse / CW (Continuous Wave) mode에 있어서 전자온도의 측정을 위해 emissive probe 를 이용하여 plasma potential과 floating potential을 측정하였으며, 이를 통하여 전자온도를 계산하여 구할 수 있었다. Duty ratio 및 pulsing frequency의 변화에 따른 전자온도의 변화를 확인 할 수 있었으며, 그에 따른 플라즈마 균일도를 ion saturation current를 측정함으로써 관찰할 수 있었다. 실제 식각 공정에 있어서 Pulsing 조건에 따른 식각 특성을 관찰하기 위해, SiO2, ACL (Amorphous Carbon Layer)에 대해 식각을 진행하였으며, 식각 메커니즘 분석을 위해 이온에너지 분포의 변화를 PSM (Plasma Sampling Mass-spectroscopy)을 이용하여 측정하였다.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.8
• /
• pp.2072-2087
• /
• 1999

As software size ever increases and user's requirements become more and more sophisticated., the importance of software quality is more and more emphasized. However, we are not satisfied for the present techniques on detecting errors and checking consistency in the object-oriented design model. This paper proposes a systematic approach which produces implementable rules to detect errors and check consistency. At first, the meta-models for UML diagrams are constructed, generalized meta-rules are reduced from the meta-models, and then the meta-rules are applied to produce the implementable rules. This approach enables to pursue the completeness of the rules and the automation of rule application. An example of rule application shows the feasibility of the rule application.