• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.105-110
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• 1992

This study deals with the effect of a series of moving trucks on the Dynamic Load Factor (DLF). The DLF is calculated by investigating the load effect of moving trucks. Therefore, analytical models for frocks, bridge, and road profiles were developed and dynamic structural analysis computer program were developed. Then the DLFs are calculated as a ratio of maximum dynamic load effect and maximum static load effect. Trucks used in this study are 5 axle semi tractor-trailer with the weight of 36 and 54 ton. Simply supported prestressed concrete box girder bridges with 20 and 40m span length are selected. From the results of the DLF for various headway distances, they show a very scattered and relatively high values of the DLF in case of a 20m span length bridge. For a 40m span length bridge, the results show less scattered and small increase of the DLF compared to a 20m span length bridge.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.5
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• pp.423-431
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• 2000

In this paper, the effect of computing time-delay in the real-time digital fuzzy control systems is investigated and the design methodology of a real-time digital fuzzy controller(DFC) to overcome the problems caused by it is presented. We propose the fuzzy feedback controller whose output is delayed with unit sampling period. The analysis and the design problem considering computing time-delay is very easy because the proposed controller is syncronized with the sampling time. The stabilization problem of the digital fuzzy control system is solved by the linear matrix inequality(LMI) theory. Convex optimization techniques are utilized to find the stable feedback gains and a common positive definite matrix P for the designed fuzzy control system Furthermore, we develop a real-time fuzzy control system for backing up a computer-simulated truck-trailer with the consideration of the computing time-delay. By using the proposed method, we design a DFC which guarantees the stability of the real time digital fuzzy control system in the presence of computing time-delay.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.497-500
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• 1999

고속전철의 보조 전원 장치는 차량에 탑재되므로 소형화, 경량화 및 고신뢰성이 요구된다. 보조전원 장치중 Battery Charge는 고압의 직류전원(670Vdc)을 저압의 직류전원(83Vdc)으로 변환하여 객차(Trailer Car : 50kW) 및 동력차(Power Car : 10Kw)에 필요한 직류전원을 안정되게 공급하고 Battery Charger의 고장 발생 시를 대비해 Battery의 최적 충전상태를 유지해야 한다. 기술개발의 최종 목표는 고효율, 고신뢰성 밧데리 충전기 시스템 개발, EMI 저감, 부피와 무게의 소형경량화, 최적 스위칭 기술 및 회로 개발이다. IGBT에 대해 소프트 스위칭 기법을 사용하여 스위칭 손실 저감 및 소자의 스트레스의 저감으로 전력 변환 장치의 효율 향상과 소자의 신뢰성을 확보하였고, 스위칭 주파수를 높여 변압기나 인덕터등의 자기 소자의 크기를 줄였다. Battery Charger를 단일 모듈로 구성하기 보다 5kW 모듈을 여러개 조합한 다중모듈방법으로 병렬 운전하므로써 입출력 전류리플룰 감소시켰으며 시스템의 안정성과 신뢰성을 높일 수 있었다.

• Bulletin of Food Technology
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• v.18 no.1
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• pp.91-98
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• 2005

Aims: As a preliminary experiment on new sanitizer delivery tools, the efficacy of aerosolizedsanitizer on foodborne pathogens was investigated in larger model chamber system.Methods: Peroxyacetic acid and hydrogen peroxide were aerosolized in a model system againstartificially inoculated target microorganisms on laboratory media. Cultures of 4 different foodborne pathogens were inoculated and affixed onto 3 different heights (bottom, wall, and ceiling), and 3different orientations (face-down, vertical, and face-down) inside a commercial semi-trailer cabinet(14.6 x 2.6 x 2.8 m). Sanitizer was aerosolized into 2 m droplet size fog and treated for 1 h atambient temperature.Results: Populations of Bacillus cereus, Listeria innocua, Staphylococcus aureus, and Salmonellatyphimurium were reduced by an average of 3.09, 7.69, 6.93 and 8.18 log units per plate, respectively.Interestingly, L. innocua, Staph. aureus, and Salm. typhimurium showed statistically not different (P$\leq$ 0.05) reduction patterns relative to height and orientation that were never expected in a sprayingsystemConclusion and significance: Aerosolized sanitizers diffuse like gaseous sanitizers, so it has greatpotential for use in commercial applications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.277-281
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• 1997

Reliab~l~ty englneerlng IS regarded as the major and important roll for all Industry And advanced nianufactur~ng systems w~th h~gh speed and lntell~gent ha\\ulcorner been dcvelop~ng for betterment of lnachln~ng db~l~ty In th~study, Me have rystem~~ed c\, ~luat~on c r f relidb~litl for nldchlntry system We proposed the rel~ab~l~ty asvxmcnt and dci~yned and manufactured r~ildb~llty tcst-bed to eualuate rcl~dbil~ty In ddd~t~on we acquired relldb~l~ty data uslng test-bed sydem and mde database to handle relrab~l~t) data And also he not only use rel~ab~l~ty data by andlyzlng rel~ab~l~ty, but also apply design revlew method usmg analycing crltlcal unlt5 of machlnery system From th~s stud), he u ~ l l expect to gu~de md Increase the rel~ab~l~t) englneerlng in devclop~ng and procerslng phase of h~gh qualrty product

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.138-144
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• 2014

This study investigates the air resistance due to deflector configurations of commonly used largetrucksat a driving speedof 80 km/h. Of the 6 models that are considered, the drag causedby the pressure on the front part of the trailer is largest for model 1. For model 1, the lift caused by the difference between the velocities of the upper and lower streams isgreatest amongall the models. Model 6 has the least resistance against the flow stream consideringthedrags and lifts of theflow models. Anoptimal design can be obtainedby investigating thesimulation analysis ofvarious deflector configurationsfor the upper part of largetrucks; this optimum deflector configuration will help reduce the air resistanceon large trucks.

• Journal of KSNVE
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• v.10 no.4
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• pp.636-641
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• 2000

KHST(Korea High Speed Train) project plans to design and to build an high speed train. There are noise requirements in passenger room for the standing and running condition, which should be reached. Predicted noise calculated for the standing and running TM5(Motorized car) and TT4(Trailer car) train (v=300 km/h and v=350 km/h) to find out critical areas in or around the train. From the estimation in DWA IfS, actions of noise reduction are proposed to reach the requirements. This paper takes the review of the calculated results in DWA IfS to propose a new design of inner wall.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1232-1240
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• 2001

In this study. a computer simulation of the Korean High Speed Prototype Test Train was performed to investigate the dynamic behavior(running stability. safety and comfort) in detail design process. The simulation model which was prepared by ADAMS/Rail V10.l consists of power car and middle car assembly (2 motorized cars ＋ 3 trailer cars). The nonlinear analysis takes into account the full vehicle model including wheel/rail contact and the influence of disturbed track. Throughout the dynamic calculation of KHST on the straight and the curved track. accelerations in car body. ride comforts and wheel rail forces were investigated.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.261-264
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• 2001

In this paper, we design IP of ATM AAL layer for B-ISDN. The designed ATM AAL module supports the function for AAL type 0, AAL type 3/4, AAL type 5. The designed IP provides for automatic CRC-32 and CRC-10 for AAL type and AAL type 3/4. Also our IP inserts and extracts the header and trailer for each type automatically. After HDL description, it is verified by the simulation. The designed U is implemented in Xilinx FPGA. Rx AAL module operates at 35MHz and Rx AAL module operates at 50MHz. The designed IP can be applicable in high-speed ATM SAR(Segmentation and Reassembly) chip.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.62-73
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• 2001

The scope of this study is focused on the survey of new logistics transportation systems in railroad and case studies of new systems such as piggyback system, bi-modal system swapbody, and double stack train(DST). Piggyback system, bi-modal system, swapbody, and double stack train are reviewed in term of technological validity and economic validity in Korea. Piggyback - trailer does pass loaded weight limits but does not pass train limits and can not utilize the existing freight cars. Piggyback - cargo trunk does pass all the criteria and could be developed by a domestic technology. But this study suggests to expand the length of train cars to 18.300mm for accommodation of two cargo trucks. Bi-modal system and swapbody do also pass. Double stack train could only pass the loaded weights and does not meet the train limit and the possibility of using existing freight cars. Domestic technology could not development DST, due to civil engineering construction limits and low standard height of electric line, which could not afford to operate DST.