• Journal of Environmental Science International
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• v.17 no.4
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• pp.451-459
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• 2008

This study was carried out forecasting of pollution inflow of the Small Mountainous Catchment, namely; Seolma-cheon experimental catchment. Pollutographs of DO, BOD, T-N, Conductivity, T-p, pH. COD, SS from this catchment were obtained from in-situ data of total ten events using QUAL2E-PULS model. From the analysis results, between up stream(Sabang-bridge) and down stream (Memorial-bridge, outlet) obtained relation formula of water quality component. Determination coefficient of relation formula, Conductivity, COD, BOD, DO, pH, T-N, T-P, and SS showed high relation of $0.87{\sim}0.99$. The increases of DO, BOD, COD, and pH concentration of Memorial-bridge were associated with pollution inflow by road building far 2.25km from Sabang-bridge to down stream. The analysis results of QUAL2E-PULS simulation and up/down stream relation formula, pollution amounts of DO, BOD, COD and pH increased at Memorial-bridge and pollution source site. Therefore, pollution inflow can be forecasted exactly by up/down stream relation formula at pollution source site.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.110-117
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• 2004

The aim of a benchmark study is carried out nine methods are employed for ULS analysis which implicitly predict the ultimate strength of aluminium stiffened panels under axial compression. For this purpose, DNV PULS, experimental and numerical data on the ultimate strength of panels were collected. Comparison of these experimental / numerical, DNV PULS / numerical, results with theoretical solutions by the candidate methods is performed. Also it's compared that ALPS/ULSAP program is based on closed-form formula for the ULS of plates and grillages under axial compression. It is considered that ALPS/ULSAP methodology provides quite accurate and reasonable ULS calculations by a comparison with more refined FEA. Comparison of these experimental data, numerical, computational software results with the simplified solutions obtained by the candidate methods is then performed. The model uncertainties associated with the candidate methods are studied in terms of mean bias and COV (i.e., coefficient of variation) against experiments and numerical solutions, and the relative performance of the various methods is discussed.

• Journal of Ocean Engineering and Technology
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• v.23 no.5
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• pp.71-78
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• 2009

In ship design or offshore structure design, the evaluation of buckling strength (or ultimate strength) is critical to the determination of scantling of stiffened plates. For this reason, it is useful to study the effect of applying different formula or the relationship between stiffened plate with buckling utilization factor (UF). It can facilitate a designer to decide how much the scantling should be reinforced or how much can be reduced for an optimal design. This paper conducts a comparative study for three buckling check methods; DNV-Ship-Rule, DNV-RP-C201, DNV-PULS. The capacity curves and 2D contour plot for utilization factors versus bi-axial in-plane stresses are compared. The contour plots of DNV-Ship-Rule and DNV-PULS show smoothly increasing trends of UF as the applied in-plane stresses increase, however that of DNV-RP-C201 shows rapidly increasing trend as the applied stresses go beyond transverse buckling stress. A sensitivity analysis is performed to investigate the influence level of each parameter of a stiffened plate on UF. Resulting from the analysis, plate thickness is identified to be the most affective parameter to UF regardless of the buckling check methods. Based on the addressed study, optimal designs for bottom plate of 165 K tanker corresponding to three formulas are compared with each other. DNV-PULS yields 1 mm and 2 mm less thickness than DNV-Ship-Rule and DNV-RP-C201, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1649-1653
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• 2008

오염거동에 관한 연구는 일반적으로 도시하천 및 농업지역의 하천유역에서 이루어는 것이 일반적이나, 우리나라의 약 70% 정도가 산지유역으로 작은 산지하천이 발달되어 있는 점을 고려하면, 산지 소하천 유역의 오염거동 분석은 매우 의미 있다고 본다. 본 연구 대상유역인 설마천 시험유역(경기도 파주시 적성면 소재, 한국건설기술연구원 시험유역 운영 사이트)은 계곡을 중심으로 음식점과 휴게소가 발달되어 있고 소규모 농가 및 3개 군부대가 위치하는 등 비교적 적은 오염원이 존재하는 곳이다. 최근 4개년($2003{\sim}2006$년) 자료를 이용하여 대상 유역의 상 하류 2개 지점의 동시간대의 수질자료를 바탕으로 오염거동을 모의하여 각 Segment별 오염량을 산정하고 유출부인 전적비교 지점과 실측값을 비교 하였으며, 검증된 모의값을 토대로 수문조건별 수질항목별 상 하류 관계식을 도출하였다. 본 연구 대상유역의 분석을 위해 총 10개의 실측 자료와 QUAL2E-PULS 모형의 모의를 토대로 각 Segment별 오염량을 산정한 결과 98% 이상의 정확도 높은 자료를 얻었다. 이 결과를 토대로 2개 지점간의 수문조건별 수질항목별 상 하류 관계식 도출하였으며, 전기전도도, COD, BOD, DO, pH, T-N, T-P 및 SS 순으로 $98.9{\sim}87.8%$ 정도의 높은 결정계수를 보이는 것으로 분석되었다.

• Journal of Korea Water Resources Association
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• v.37 no.1
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• pp.43-54
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• 2004

The objective of this study is to propose reservoir operation method in relation to the suspended sediment concentration due to rainstorms. Present analysis is made for the Tamjin reservoir which is under construction. For the hydrologic computations the Huff rainfall distribution, Clark unit hydrograph method and Puls reservoir routing method are used. The variation of suspended sediment concentration is calculated by 2-dimensional RMA-4 model. As a result of this study, the possible intake time from the reservoir under low frequency flood is estimated and the rainfall-ret urn period - possible intake time relationship is established, which is very important in maintaining the water quality standard when supplying water from the reservoir for different utilizationurn period- possible intake time relationship is established, which is very important in maintaining the water quality standard when supplying water from the reservoir for different utilizations.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.301-304
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• 1989

This paper desoribes a method which can make easily the calculations of current and instantaneous output torque by using the representation techniques of Inverter output voltage space vector. And also, a technique for determinations the optical PWM switching patterns which can boost a output voltage and can minimize higher order harmonic components through appropriate movements of output voltage space vector is introduced.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.104-104
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• 2001

Purpose： In this study, we investigated the possible motor pathways of hemiplegic stroke patients usin combined TMS and BOLD fMRI approach and evaluated the correlation between TMS a fMRI methods. Method： Four subjects, who demonstrated left hemiplegia after stroke, are included. TMS was performed using a Dantec Mag2 stimulator (Dantec Company, USA) in single puls mode with figure eight-shaped coil. Following TMS localization, The BOLD T2＊-weight images were acquired with echo planar imaging sequence (TR = 1.2 sec, TE = 60 msec, and flip angle = 90). Motor activation was studied by means of a repetitive fing flexion-extension task. The stimulation protocol comprised 10 cycles of alternating activati and rest (10 images per cycle). Total 60 cycles were performed and each cycle take abou 1.5 sec. The resulting images were then analyzed with STIMULATE (CMRR, U, o Minnesota) to generate functional maps using a student t-test (p < 0.0005) and cluste analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.499-504
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• 2004

The purpose of this study is to investigate a investigating of a floor-impact isolation system using damping materials in apartment buildings. The stiffness elastic modulus(k) by puls impact forces were calculated loss factor by Hilbert transforms. It is absolved that natural frequency was moved floor shock-absorbing materials and the impact force was reduced by floor panel. The slab was constructed by damping materials. As towards a result, the system showed inverse A 45dB by heavy weight-impact noise and inverse A 52dB by light-impact noise. High frequencies impact-noise can be reduced by upgrading naturial frequency of vibration and noise in the system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.1-7
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• 2021

In this study, MIG welding was performed on extruded 6005A-T6 material, which is used in the base panel of railway vehicles. The material was considered as the experimental base material, and argon shielding gas and ER5356 and ER4043 filler metals were used as the consumable welding materials. Welding coupons were prepared under various welding conditions by using an auto-welding system that various welding conditions applied 2.5Hz and 4.5Hz the pulse frequency of SynchroPuls function of welding machine and 1.0mm and 1.5mm of root face affect the weld penetration of welding joint. The welding current and voltage were also varied for this testing. On the basis of the results obtained, optimum welding conditions are proposed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.17-25
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• 2021

In this study, the mechanical properties of railway-vehicle aluminum under frame was investigated based on the metal inert gas (MIG) welding conditions. An aluminum-alloy (6005A-T6) extruded material used in the lower panel of a railway vehicle was connected through MIG welding to determine the mechanical properties of MIG welds. Argon shielding gas and filler materials, such as ER5356 and ER4043, were used as consumable welding materials. For the welding conditions of the test specimen, welding frequencies of 2.5 and 4.5 Hz were applied using the SynchroPuls function, and the root faces were 1.0 and 1.5 mm. The mechanical properties of the MIG welds were determined through tensile, bending, and fatigue tests.