• Korean Journal of Construction Engineering and Management
• /
• v.3 no.1 s.9
• /
• pp.115-123
• /
• 2002

Recently all basement floor of apartment site have utilized as parking area to use efficiently space and to ensure lawful parking car figure. And the top of parking area has used as working vehicle's path and materials' carrying area during construction. Thus because crack and leakage status in underground parking area of under construction or completion building generate excessively not only performance of structure is diminished but also flaw repair cost is put in a lot of. And abroad confidence is diminish. So this study is intended to diminish flaw focus on investigation of under construction and completion fields through examine closely cause of crack and leakage status of apartment house underground parking area and prepare countermeasure with respect to design, construction and maintenance.

• Structural Engineering and Mechanics
• /
• v.15 no.1
• /
• pp.53-70
• /
• 2003

The motivation of this paper is to introduce the modern technology of large-scale cooling tower design. Thereby the innovative design concept for the world's largest cooling tower with a height of 200 m is briefly presented (Harte & Kr$\ddot{a}$tzig 2002, Bush et al. 2002). The new concept was considered not only for safety, but also for preservation of the durability of the structure, because cracking damage in large cooling towers in general cause extremely high cost of maintenance and repair. The paper demonstrates numerically the damage process in large cooling towers (Kr$\ddot{a}$tzig et al. 2001), and describes some basics of the numerical finite element approach for damage propagation modelling of shell structure. A prototype is analysed to trace the progressive damage process, whereby the changes in the dynamical behaviour of the structure, as mirrored in its natural frequencies and the corresponding mode shapes, are presented and discussed. Finally, the example shows that such damage processes develop progressively over the life-time of the shell structure.

• Corrosion Science and Technology
• /
• v.3 no.4
• /
• pp.166-171
• /
• 2004

Recent developments in Bridge Management Systems (BMS) and in Life-Cycle Cost (LCC) of bridges, have raised the need for evaluation procedure of future condition (Deterioration) of a bridge. Predicting future deterioration is not an easy task due to limited past data to extrapolate from and also due to difficulty in measuring actual deterioration such as section loss of steel on an actual steel bridge. Also, increase in live load and reduction of resistance are random variables, thus a probabilistic approach should be adopted for determining the future deterioration. Due to difficulties in evaluation of future deterioration on steel bridges, accepting uncertainties within a reasonable error, a deterministic procedure using bridge condition rating can be a useful tool for projection of future condition of bridges to identify repair and maintenance needs. The object of this paper is to determine applicability of evaluating deterioration of steel bridge components based on Bridge condition ratings. Bridge condition ratings of bridge components show wide variation for bridges of same age and does not directly correlate well with the age of the bridge and/or deterioration of the bridge. High uncertainty can be reduced by breaking down the rating and by sensitivity analysis. From refined condition rating data, generalized deterioration profile of structures based on age can be derived. Examples are shown for sample bridges in USA. Approximately, 3,000 short to medium span steel bridges were listed in the inventory database. Results show wide variation of rating factors but by subdividing the Bridge condition ratings for various categories general deterioration profiles of steel bridges can be determined.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.2
• /
• pp.366-373
• /
• 2005

In this paper, we propose the method of integrating the Book Lending Management System running either on local and web to develop Enterprise Application in distributed environment more easily and quickly using Sun's EJB based on the lava. We integrate the Book Lending Management System which is operated separately using EJB. And, by designing and implementing the Book Lending Management System separately according to its functions, it can reduce the cost of maintenance and repair. At all platforms where the Internet, Book Lending service is possible, because it provide Web based interface with JSP. Then, we can get platform independent implementation using EJB and JSP..

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.12
• /
• pp.2113-2118
• /
• 2016

The precise detection of electric leakage point of underground power cable is very important to reduce cost and time of maintenance and prevent electric shock accident through expedite repair of electric leakage point. This paper proposes a electric leakage point detection system underground power cable using of half-period modulated transmission waveform and earth electric potential measurement. The developed system is composed of transmitter to generate the wanted pulse waveform, receiver to measure and display earth electric potential by the transmitted pulse in electric leakage point and PC Software program to display of GPS coordinate on detection cable line. The performance of the electric leakage point detection system was tested in the constructed underground cable leakage detection test bed. The test results on signal generation voltage precision of signal transmitter, mean detection earth voltage, mean detection leakage current and electric leakage point detection error showed the developed system can be used in electric leakage point detection underground power cable.

• Tribology and Lubricants
• /
• v.38 no.1
• /
• pp.22-26
• /
• 2022

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

• Journal of Navigation and Port Research
• /
• v.37 no.1
• /
• pp.113-121
• /
• 2013

IMO(International Maritime Organization) is existed the movement for revising ISM Code so that the maintenance history and the trouble information given trading in a ship can be transferred. An empirical analysis was made on the influence that will have upon shipping industry through surveying on the recognition on ISM Code revision in employees of the relevant field and on the expected problems given being amended ISM Code as the above. In conclusion, the positive effect is judged to be more in the aspect of ship safety, which is the aim of ISM Code, rather than the negative effect, which may take place given being revised ISM Code. In other words, the clean market can be formed through this because fairness is maintained on both sides given trading in a ship by which opening the maintenance record and the trouble history is applied equally to a buyer and a seller. Ships can be reduced a loss of time and cost in preventing similar problems and seeking solution that may appear in important equipments, through this maintenance record. Also, based on these materials, it comes to be available for analyzing a risk of ship and preventing and managing a risk, thereby being increased ability of maintenance and repair in a ship, resulting in being judged to likely contributing to ship safety and environmental-pollution prevention.

• Journal of Korean Society of Forest Science
• /
• v.76 no.2
• /
• pp.145-160
• /
• 1987

To evaluate damage status and necessities of repair works on the forest-side erosion control structures constructed from 1966 to 1986 in Korea, developmental procedures of erosion control structures from the standard unit-cost tables established by the Forestry Administration every year, existing counter-measures for disaster erosion control system administrated by the government organization and existing status of each structure at constructed site were investigated and analyzed integrally. About 10-15% of the constructed forest erosion control structures were required to be repaired as a result of the investigation. It is actually incapable of repairing the damaged forest erosion control structures caused by excessive run-off and floodings under the existing forest-side erosion control systems. Therefore, it is necessary to put regularly repair erosion control system that will be secured by national budgetary pre-allocation system. Especially, it is also necessary to frame a new system that repair erosion control works by national budget (central government) should be possible for any scale of damages in case of the erosion control projects for the disaster counter-measures. The results of this research could be adopted as important policy data for erosion control policy-making in forest-side in Korea.

• Journal of the Korean Institute of Gas
• /
• v.11 no.3
• /
• pp.56-63
• /
• 2007

These days, needs and wants of the customers are getting diversified and the market is also changing rapidely. Many organizations are now attempting change and innovation activities to improve products and service quality. This study was performed to apply 6 sigma tools for the efficient repair management of city gas supply equipment. Vital few factors, RISK factors, sigma values, root causes. and solutions were derived by 6 sigma tools. We are performing statistical process control for the new process. Six sigma for city gas supply equipment safety management enabled to improve the business management for efficiency by reducing variation and eliminating cost for quality.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.06a
• /
• pp.163-165
• /
• 2013

IMO(International Maritime Organization) is existed the movement for revising ISM Code so that the maintenance history and the trouble information given trading in a ship can be transferred. An empirical analysis was made on the influence that will have upon shipping industry through surveying on the recognition on ISM Code revision in employees of the relevant field and on the expected problems given being amended ISM Code as the above. In conclusion, the positive effect is judged to be more in the aspect of ship safety, which is the aim of ISM Code, rather than the negative effect, which may take place given being revised ISM Code. In other words, the clean market can be formed through this because fairness is maintained on both sides given trading in a ship by which opening the maintenance record and the trouble history is applied equally to a buyer and a seller. Ships can be reduced a loss of time and cost in preventing similar problems and seeking solution that may appear in important equipments, through this maintenance record. Also, based on these materials, it comes to be available for analyzing a risk of ship and preventing and managing a risk, thereby being increased ability of maintenance and repair in a ship, resulting in being judged to likely contributing to ship safety and environmental-pollution prevention.