• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.1-10
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• 2004

A study on the evaluation of proper spacing and required flexural rigidity of cross beams in composite two I-section steel girder bridges without a lateral and sway bracing system was performed. Specifically, a 2-lane, 40-m simple span bridge and a 3-span continuous (40+50+10m) bridge were designed, and structural analyses under dead load before and after composite, live, wind, and seismic loads were performed using spacing and flexural rigidity or cross beams as parameters. Through parametric analysis, the effect on the stresses due to the combination of loads and live load distribution was investigated. In addition. material and geometric nonlinear analyses under dead load before composite were performed to evaluate the lateral buckling strength of the steel girders and cross beam. Based on the results or such analyses, the proper spacing and flexural rigidity of cross beams at intermediate points and supports were proposed.

• Tunnel and Underground Space
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• v.14 no.2
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• pp.154-166
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• 2004

A numerical stability analysis was conducted on the large oil storage caverns excavated in a rock mass under high initial horizonal stress. The behaviors of the surrounding rock mass, rockbolts, and shotcrete were analyzedr and stability of the support members were assessed. For a proper support system design, the effect of the modelling technique, cavern shape and rockbolt length on the stability of the cavern was investigated. Results show that installation timing of supports and the change in cavern shape due to stepwise excavation affect the stress induced in support members. Also found was desperate need for a numerical technique which can properly reflect the behavior of the steel fiber reinforced shotcrete.

• Journal of Internet Computing and Services
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• v.3 no.6
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• pp.25-33
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• 2002

The efficiency of the data share service of P2P method is decided by the maintaining guard method of a sharing list, This paper suggests the data sharing system of the P2P base that it should retain a shared data list at a client, The Server at a proposed system guards inclusively client. divided into several groups and at each individual group, a client appointed the TopHost uses the method guarding a free share list of a applicating group, The TopHost designs to execute it relating with server in case of the mergence and the division of a group as well as a maintaining management of a data share list, The efficiency of the suggested system regard the maintaining guard of groups formed of a client of the appropriate level of a kernel and exams examination to measure it through a really executed data share service.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.169-170
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• 2006

대형화, 고압화되고 있는 전력설비는 사고가 발생할 경우 그에 수반되는 산업, 경제, 사회적인 손실의 규모가 매우 커지는 경향을 가진다. 특히 적정온도 이상에서의 운전은 전력설비의 오동작을 일으키는 주요한 원인 중 하나이므로 비정상적인 온도상승을 조기에 감지하여 사고의 가능성을 감소시키는 시스템의 개발은 안정적인 전력설비 운용에 반드시 필요한 요소기술이다. 기존의 감시 시스템은 대부분 여러 위치의 정보를 동시에 얻기 위하여 여러 개의 개별 센서를 배열하여야하므로 대형중량화가 불가피하다는 단점을 갖고 있다. 그러나 광섬유 FBG 온도센서는 전자기 간섭의 영향을 받지 않고, 여러 개의 센서를 하나의 광섬유 라인에 설치하여 동시에 여러 부위의 온도를 측정할 수 있는 준분배형 온도센서 구현이 가능하다는 장점으로 과열감시 시스템에 적합한 센서로 인식된다. 본 연구에서는 광섬유 FBG 온도센서를 이용하여 변압기 단락시험을 통해 변압기의 온도 변화를 T-type thermocouple(이하 TC)과 동일한 지점에서 측정하고, 그 데이터를 비교분석함으로써 광섬유 FBG 온도센서 시스템의 신뢰성을 검증하였고, 이를 전력용 변압기 과열감시 시스템으로 적용할 수 있음을 제시하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1874-1881
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• 2008

This study surveyed and analysed the factors that affect the job satisfaction of a home appliances service engineer. The job satisfaction analysis was based on two separate branches: the satisfaction of the current position and the intention to work. As the result, it was apprehended that as far as the individual qualities of the engineer are concerned, personality is a factor that had an effect on job satisfaction. Concerning the organisational qualities, it was analysed that social support, allowances and welfare were factors that contributed largely; and concerning the work itself, it was acknowledged that the appropriateness of the work influenced job satisfaction. To conclude, it was analysed that to increase job satisfaction, it would be important first and foremost to employ employees who have extroversive personalities, to take good care of the allowances and welfare of the employees and to distribute appropriately the amount of work.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.133-140
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• 2018

A nonlinear finite element analysis was conducted in order to examine the moment capacity and flexural behaviour of hollow prestressed concrete filled steel tube(HCFT) piles which compose hollow PHC piles inside thin wall steel tubes. The parameters investigated in this study were various contact conditions between concrete and steel tube, thickness of concrete tube and various PC strands. A simple method is proposed to determine the ultimate flexural strength based on plastic stress distribution method. In order to verify the proposed method, calculated moment capacity of various HCFT piles are compared with the experiment and numerical analysis results.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.35-43
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• 2008

This study was carried out to estimate the performance of modified sequencing batch reactor (SBR) process by the application of SBR process for small advanced wastewater treatment plant. Organic, nitrogen and phosphorus were able to remove in the unit reactor by SBR process and it would be able to select the suitable operation method. The plant was operated to achieve high performance with influent control, optimum anoxic/oxic condition using intermediate aeration method, and solid (sludge) /liquid (effluent) separation by modified decanter. The optimum operating mode was 3Cycles a day and intermediate input and aeration. Under these conditions, the treatment efficiencies were good with 60% of designed flow rate and low influent quality. When the influent concentrations of BOD and CODMn were 120.4 mg/L and 95.7 mg/L, respectively. The effluent concentrations of BOD and CODMn were 6.8 mg/L and 11.0 mg/L, respectively. The average removal efficiencies of BOD and CODMn were 94.4% and 88.5%, respectively. The removal efficiencies of T-N and T-P were 69.6% and 73.6%, respectively when the average T-N and T-P concentrations were 32.2mg/L and 4.65mg/L, respectively. The T-N and T-P removal efficiencies were slightly decreased to 58.8% and 68.5%, respectively in the winter season but its were also stable efficiencies. BOD, T-N and T-P were removed by 90%. 67% and 46% respectively in the first anoxic/oxic condition, in addition to T-P was removed by 70% in the second anoxic/oxic condition. From the results, modified sequencing batch reactor (SBR) process is suitable for small advanced wastewater treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.5-13
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• 1978

An experiment was carried out to find out effective heading date and period of limited ripening in different regions of climatic conditions by sowing date and length of nursery stage of a new variety Milyang 23. Since varieties of Tongil line have a character of premature heading, these do not show the symptom of senescent even though length of nursey stage was delayed. And the delay of heading date is due to late transplanting date, on the other hand, length of nursery stage delayed.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.519-525
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• 2008

Biodegradation of toluene, styrene and hydrogen sulfide as model compounds of volatile organic compounds and odor from waste gas was investigated experimentally in a biotrickling filter. This study focussed on the description of experimental results with regard to operating conditions. The effect of varying $H_2S$ load rate and inlet concentration was investigated under autotropic and mixotropic environmental conditions. The $H_2S$ removal efficiencies of greater than 99% were achieved at $H_2S$ loads below $10g/m^3{\cdot}hr$ for each environment. It was observed that the maximum elimination capacity of mixotrophic filter was achieved a little greater than the one of autotrophic filter. The biofiltration of toluene and styrene in trickling bed was examined under different gas flow rates, load rates, and inlet concentrations. Below $40g/m^3{\cdot}hr$ of toluene loading, the elimination capacity and loading were identical and it was completely destroyed. In high loading of toluene, the biotrickling filter was operated at its maximum elimination capacity. In the inlet concentration of 0.2, 0.5, and $1.0g/m^3$, the maximum elimination capacity of toluene showed 40, 45, and $60g/m^3{\cdot}hr$, respectively. After a short adaptation period, it was demonstrated that the results of styrene in originally toluene adapted bioreactor was similar with the ones of toluene. However, the performance of filer for styrene is generally a little lower than for toluene. The operating conditions (including liquid flow rate etc.) allowing the highest removal efficiency should be determined experimentally for each specific case.

• Plant Journal
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• v.11 no.2
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• pp.32-38
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• 2015

This study was conducted on combined cycle power plant consisting of HRSG with integral deaerator type to avoid tube failures of low pressure evaporator tubes. Based on the observation of pH variation at the discharge of boiler feed water pump by continuous pH measurement for a period of time, it was identified that pH of feed water is getting reduced as ammonia is distributed into vapor and liquid depending on the distribution ratio of ammonia in the LP drum after the deaerator. To solve this problem, the counterplan was prepared by reexamination of ammonia injection point and quantity. In conclusion, it was accomplished that 9.2~9.6 is the optimized pH range for boiler feed water by arranging additional piping for ammonia to inject directly to LP drum.