• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.221-225
• /
• 2015

To hoist construction workers to their working space is directly related to the productivity of building construction since hoisting tasks are carried out during the working time. In order to reduce hoisting time in the condition that the number of construction lift-cars is limited, various types of the lift-cars group operation plans such as zoning and sky-lobby have been applied. However, previous researches on them cannot be compared in the performance due to their methodological limitation, discrete-event simulation methods, and cannot be find better solution to increase the performance. Therefore, this research proposed the simulation-based optimization model combining the agent-based simulation method to the scatter search optimization methods. Using the proposed model, this paper carried out the comparison analysis on the performance of typical operation plans and also optimize an operation plans by controlling the service range of lift-cars, the size and number of service zones. In this case study, it is verified that better alternatives than typical operation plans can be exists and it is possible to increase the productivity of building construction.

• Proceedings of the KIPE Conference
• /
• 2011.11a
• /
• pp.40-41
• /
• 2011

Partial shading on a Photo Voltaic panel can generate the local maximum power points on the powervoltage curve of the panel. Presence of the local peaks can disturb the efficient operation of maximum power point tracking (MPPT).In this study, the MPPT under partial shading condition is investigated. To circumvent the trappings into the local peaks, the results of the study are enumerated and discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.873-876
• /
• 2002

This paper presents the effect of internal corrosion, external corrosion, material properties, operation condition, earthquake, traffic load and design thickness in pipeline on the failure prediction using a failure probability model. A nonlinear corrosion is used to represent the loss of pipe wall thickness with time. The effects of environmental, operational, and design random variables such as a pipe diameter, earthquake, fluid pressure, a corrosion rate, a material yield stress and a pipe thickness on the failure probability are systematically investigated using a failure probability model for the corrosion pipeline.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.58-63
• /
• 1993

The charactistics of AE(Acoustic Emission) signal is related to cutting conditions, tool materials and tool geometry in metal cutting. The tool geometry change which is derived from tool wear affects the source of AE signal in machining process. The relationship between AE signal and tool wear was experimentally investigated. THe value of RMS(Root Mean Sequare) and Amplitude of AE signal were increased in tool wear condition. Also the high value of Count per Hit and Count vs. Frequency was observed in this condtion. As a result, tool wear can be effectively detected by AE signal during cutting operation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1997.04a
• /
• pp.82-87
• /
• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstation to provide the required intelligence of the expert. This paper deals with condition monitoring for tool wear and fracture during turning operation. Developing economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique are proposed. The validity of the proposed system is confirmed through the large number of cutting tests.

• Journal of Chest Surgery
• /
• v.27 no.10
• /
• pp.882-884
• /
• 1994

Congenital lobar emphysema is one of the abnormal development of pulmonary parenchyme which may cause respiratory distress in infant. This disease is an unusual condition barely mentioned before 1949, and only 166 cases were reported till 1967 in English literature. This report describes a 13 months old girl who had a congenital left upper lobar emphysema. The left upper lobectomy was the operation for this case and the postoperative course was not eventful, and have been in good condition upto now.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08b
• /
• pp.1152-1154
• /
• 2007

The distributions of mercury (Hg) in the bulb of a mercury vapor lamp are significantly affected by its turn-off conditions. Most of mercury should be attached to the electrodes before ignition by a proper turn-off condition. In the present study, the effect of the transient profiles of lamp cooling after turn-off on the distribution of Hg was investigated.

• Proceedings of the Korean Reliability Society Conference
• /
• 2002.06a
• /
• pp.403-410
• /
• 2002

This paper presents the effect of internal corrosion, external corrosion, material properties, operation condition, earthquake, traffic load and design thickness in pipeline on the failure prediction using a failure probability model. A nonlinear corrosion is used to represent the loss of pipe wall thickness with time. The effects of environmental, operational, and design random variables such as a pipe diameter, earthquake, fluid pressure, a corrosion rate, a material yield stress and a pipe thickness on the failure probability are systematically investigated using a failure probability model for the corrosion pipeline.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.396-397
• /
• 2008

In order to evaluate the nominal rating of breakers in distribution system due to the increased capacity of power transformer from 60 to 100 MVA, the fault currents are calculated in the condition of 3-phase fault and single line-to-ground fault. Consequently, under the condition of the parallel operation of transformers the fault currents were exceed the nominal rating current of breakers in some areas.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.05a
• /
• pp.212-215
• /
• 2008

In this paper, the recent technologies of a guardlamp are surveyed and the research on the actual condition of the management and maintenance is carried out. In addition, this paper intends to arouse people's attention to the electrical disasters caused by neglecting the installation, operation, management and maintenance of the guardlamp. In the process of the research, a field survey, a meeting of interested persons and manufacturers were performed and their opinions were reflected.