• Proceedings of the KSR Conference
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• 1998.05a
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• pp.172-183
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• 1998

The purpose of this study is to reduce the number of employees hired by Seoul Metropolitan Subway Corporation(SMSC) as a way of responding to deteriorating financial deficit problem. For the reduction, the personnel structure of Seoul Metro Rapid Transit Subway(SMRTS) newly founded in 1995 is benchmarked. Several assumptions are set for seeking the persuasive alternative; 1) no compulsory reduction of existing personnel, 2) raising the salary of SMSC to the same level of SMRTS for compensating intensified work burden, 3) hiring new employees to the amount of one-third of the reduced workforce for minimizing the problems associated with the reduction. The study suggests that the personnel reduction in relevant parts be planned in the following ways; 1) passenger transport part: from daily 3 shifts of 4 group to 2 shifts of 3 group, 2) fleet inspection, civil d: electric engineering, railtrack maintenance, signal parts: from 12 day-off to 10day-off, 3) architecture, AFC parts: from 2 shifts of 3 group to daily work, 4) fleet maintenance, architecture parts: expanding out-sourcing ＆ automation, and 5) headquarter part: 10% reduction of the total of office workers. The study finds, by implementing the plan, that 1,270 employee can be reduced, and that aggregate 106.8 billion won will be saved for the next 10 years.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.152-160
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• 2008

Since wall system apartment used the shear wall as main lateral resistance member, installation of openings which causing section loss of walls may cause significant problem to structure. Also, there are few studies for inducing coupling beam or slabs which are occurred by installing openings. Therefore, this study planned isolated 2-story shear walls which are reduced three half-scale specimen to find out walls behavior characteristic. The test results showed that strength reduction caused by loss of effective section of walls and different result of stiffness and energy dissipation regarding to the coupling beam and coupling slabs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.420-425
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• 2010

In the process of warm forging, billet is heated up to $800^{\circ}C$ and located in the upper part of die block impression. The scattered oxidized scale may cause workers burn and shortening of die life sticking to the die block impression. The separating materials sprayed in die block cause harmful dust, harmful mist, fume, and bad odor which contaminate workshop environment. The process is classified as one of the avoided jobs and make the planned output achievement difficult. Development of an elimination device to clear out the contaminating materials in the workshop and improvement of the unsatisfactory maintenance method to fix the abrasion of die block impression which delays the dead line, cost increases needs to be developed. In this research, I tried to solve the problems caused in warm forging of bronze pipe joint such as the billet heating process, die maintenance, and manufacturing cost through improvement of warming forging manufacturing method and die maintenance method and eliminating harmful gas which will make the workshop more environment friendly.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.477-487
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• 2021

Due to the global climate change, Korean peninsula is has been experiencing flooding and drought severely. It is hard difficult to manage water resources sustainably, because due to intensive precipitation in short periods and severe drought has increased in Korea. Reused water from the wastewater treatment plant (WWTP) could be a sustainable and an alternative water source near the urban areas. In order to understand the patterns of water reuse in Korea, annual water reuses data according to the times and regional governments were investigated from 2008 to 2019. The reused water from WWTP in Korea has been mainly used for river maintenance flow and industrial use, while agricultural use of water reuse has decreased with time. Metropolitan cities in Korea such as Seoul, Busan, Daegu, Ulsan, and Incheon have been mainly used reused reusing water for river maintenance flow. Industrial water reuse has been limitedly applied recently for the planned industrial districts in Pohang, Gumi, Paju, and Asan. By using the collected annual water reuse data from the domestic sewerage statistics of sewerage, the optimistic and pessimistic future estimations of for future annual water reuse were suggested from 2020 to 2040 on a five year interval for every five years.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1743-1753
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• 2011

Seoul Metropolitan Government has performed alternative transit system, light rail transit(LRT), for settling the problems of urban public transit system based on conventional bus service and heavy rail transit(HRT). LRT projects of total 8 lines(about 73.6km), including Ui-Sinseol line, have been planned as Build-Transfer-Operate(BTO) projects. For the first LRT, Ui-Sinseol line, however, design of structure had met standard for design of HRT, because of no domestic design code for LRT when participates of Ui-Sinseol project submitted the design proposal. This case study reports a successful example of LRT design minimizing the scale of stations designed in base of HRT code. The problems, like oversized structures compared with LRT vehicles, excessive costs for construction, had been resolved through negotiations with the participates of Ui-Sinseol line. Result suggests that present and future costs for construction and maintenance of the LRT projects in Seoul be considerably reduced in advance.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1269-1274
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• 2011

To cut down the maintenance expenses at branch lines, the foreign developed countries have developed the low-cost signalling on low-density lines. These examples are FFB(FunkFahrBetrieb) Radio based train operation by German railways(Deutsche Bahn AG), ERTMS REGIONAL by Europe and LOCOPROL system using a GPS. Also, Korea is developing Information and Communication Technology based low-cost signalling on low-density lines. The characteristics of this system are directly controled switch and crossing by driver. For the purpose of this paper, we reviewed the business process for switch and crossing control. Specially, we compared and analysed both methods whether the driver takes control over the operation procedures of switch or the control message is carried by the command of the controller. And by utilizing the instrument of UML, I planned the switch according to the control authority and the operation procedures needed for the control of crossing.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.117-124
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• 2000

This paper presents the construction planning and the detail design of a 16.2 km long railroad tunnel in a mountainous area. Major design conditions for railroad are the single track, loop-typed alinement, and a maximum grade of 24.5$\textperthousand$. A underground station(double track) with a length of 1.1km is located in the middle of the line for train cross-passing. Tunnel is excavated in highly complex geological conditions including faulted areas, abandoned mine works areas, and various rock types such as sandstone, shale, limestone, and coal seam partly. Drilling and blasting method was adopted because it is more flexible than TBM(Tunnel Boring Machine) as a result of risk assessment for geological conditions in this area. Two working adits were planned to adjust the construction schedule and can be used for ventilation and maintenance in operation phase. New material and concept were introduced to the tunnel drain design. They are expected to improve tunnel drain condition and capability. Rational tunnel support design was tried to consider the various tunnel size and purpose and to use the geological investigation results.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1822-1829
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• 2015

In this study, artificial neural networks were used to determine the intensity of brightness in interior spaces. The illumination elements to illuminate indoor spaces were considered, not individually, but as a system. So, during the planned maintenance periods of an illumination system, after its design and installation, simple brightness level measurements must be taken. For a three-dimensional evaluation of the brightness level in indoor spaces in a speedy and accurate manner, the obtained brightness level measurement results and artificial neural network model were used. Upon estimation of the most suitable brightness level for indoor spaces by using the artificial neutral network model, the energy demands required by the illumination elements decreased. Consequently, in this study, with estimations of brightness levels, the extent to which the artificial neutral networks become successful was observed and more correct results have been obtained in terms of both economy and usage.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.351-353
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• 2006

Preventive maintenance can avail the generating unit to reduce cost and gain more profit in a competitive supply-side power market. so, it is necessary to perform reliability analysis on the systems in which reliability is essential. In this paper, FMECA assessment adopted using real historical failure data in Korean power plants for apply RCM analytical method. The stochastic FMECA is an engineering analysis and a core activity performed by reliability engineers to review the effects of probable failure modes of generating unit and assemblies of the power system on system performance. Optimal RCM schedule which is considered the severity level of each generating unit and failure probability from failure prediction of generating unit can be planned using proposed FMECA with IOE index.

• The Journal of the Korean dental association
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• v.58 no.7
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• pp.398-403
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• 2020

Odontogenic anomalies can occur as a result of conjoining defects. These include fusion, gemination and concrescence. The presence of fused teeth can lead to various clinical problems, including the aplasia of permanent successor, the supernumerary teeth and delayed eruption of permanent teeth. In general, the supernumerary teeth associated with fusion is mainly found in the maxillary anterior region. This report describes rare cases of supernumerary tooth associated with fused teeth of mandibular primary lateral incisor and canine. In the first case, fused teeth was extracted. The supernumerary teeth was erupted at canine space. The second case is still being observed. Extraction of fused teeth and observation of supernumerary teeth is planned.