• 드라이브 ㆍ 컨트롤
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• 제9권1호
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• pp.10-17
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• 2012

Nowadays, the demand of energy saving is increasing more and more while the natural resources have been exhausted. Besides, the emission gas caused by vehicles has been being a serious environment problem. Therefore, many studies have been carried out, especially focusing on braking energy regeneration, in order to save energy as well as reduce emission of mobile vehicles. In this paper, we propose a closed-loop hydrostatic transmission for braking energy regeneration with two configurations to reduce the energy consumption by recovering the braking energy. The effectiveness of the proposed system was verified by simulation. The simulation results indicated that the pressure coupling configuration gave better performance in comparison to flow coupling configuration about 40.8%, 61.7% and 53.8% reduction of fuel consumption in 10 mode, 10 mode modified profile and highway schedules, respectively.

• 한국대기환경학회지
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• 제28권3호
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• pp.233-248
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• 2012

The national emission from energy sector accounted for 84.7% of all domestic emissions in 2007. Of the energy-use emissions, the emission from mobile source as one of key categories accounted for 19.4% and further the road transport emission occupied the most dominant portion in the category. The road transport emissions can be estimated on the basis of either the fuel consumed (Tier 1) or the distance travelled by the vehicle types and road types (higher Tiers). The latter approach must be suitable for simultaneously estimating $CO_2$, $CH_4$, and $N_2O$ emissions in local administrative districts. The objective of this study was to estimate 31 municipal GHG emissions from road transportation in Gyeonggi Province, Korea. In 2008, the municipalities were consisted of 2,014 towns expressed as Dong and Ri, the smallest administrative district unit. Since mobile sources are moving across other city and province borders, the emission estimated by fuel sold is in fact impossible to ensure consistency between neighbouring cities and provinces. On the other hand, the emission estimated by distance travelled is also impossible to acquire key activity data such as traffic volume, vehicle type and model, and road type in small towns. To solve the problem, we applied a hierarchical cluster analysis to separate town-by-town road patterns (clusters) based on a priori activity information including traffic volume, population, area, and branch road length obtained from small 151 towns. After identifying 10 road patterns, a rule building expert system was developed by visual basic application (VBA) to assort various unknown road patterns into one of 10 known patterns. The expert system was self-verified with original reference information and then objects in each homogeneous pattern were used to regress traffic volume based on the variables of population, area, and branch road length. The program was then applied to assign all the unknown towns into a known pattern and to automatically estimate traffic volumes by regression equations for each town. Further VKT (vehicle kilometer travelled) for each vehicle type in each town was calculated to be mapped by GIS (geological information system) and road transport emission on the corresponding road section was estimated by multiplying emission factors for each vehicle type. Finally all emissions from local branch roads in Gyeonggi Province could be estimated by summing up emissions from 1,902 towns where road information was registered. As a result of the study, the GHG average emission rate by the branch road transport was 6,101 kilotons of $CO_2$ equivalent per year (kt-$CO_2$ Eq/yr) and the total emissions from both main and branch roads was 24,152 kt-$CO_2$ Eq/yr in Gyeonggi Province. The ratio of branch roads emission to the total was 0.28 in 2008.

• 대한기계학회논문집B
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• 제35권4호
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• pp.409-416
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• 2011

차량에 의한 대기오염을 실제 주행 조건에서 시간과 공간에 구애받지 않고 실시간으로 측정하기 위하여 이동형 배출가스 측정장치 (MEL)가 제작되었다. 미니밴 차량에 배출가스 측정을 위한 장비와 입자의 수 농도 및 입경분포 측정을 위한 FMPS, CPC가 탑재되었다. 차량 전단에 장착되는 흡입 샘플링 포트를 사용하여 여러 종류의 차량 추적 실험을 수행하였다. 본 연구에서는 MEL의 구축 과정 및 디젤, CNG, LPG 연료를 사용하는 버스를 추적 실험한 결과를 나타내었다. 배출가스의 희석비는 추적차량의 엔진 배기 NOx 및 MEL 차량에서 샘플링 되는 NOx의 비로 계산하였다. 디젤버스에서 배출되는 입자의 대부분은 300 nm 이하의 크기이며 입경분포의 피크값은 30~60 nm 사이에 위치하였다. 하지만, 가스연료인 CNG와 LPG를 사용하는 버스에서 배출되는 입자들은 극미세입자 영역인 50 nm 이하로 측정되었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.651-654
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• 2007

Anthracene derivatives, 9,10trimethylsilylanthr - acene(SA) and bis(2-phenylethynyl)trimethylsilyl anthracene(Si-BPEA) were synthesized and their emission properties were studied with UV and PL spectrometers. The PL maxima of anthracene, SA, bis(2-phenylethynyl)anthracene (BPEA), Si-BPEA were obtained at 401, 438, 475, 478nm, respectively. The electro-optical properties OLED devices made with these anthracene derivatives were discussed.

• Journal of Communications and Networks
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• 제6권2호
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• pp.173-181
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• 2004

This paper shows a technique for regulating the rate emitted by UWB mobile terminals. This technique is designed to adapt the emission rate to the effects of channel capacity variations. We assume that individual flows are shaped at edge routers by means of dual leaky buckets. The proposal is based on the evaluation of certain parameters, which reflect the channel status, sent to the application layer. This information is generated by the scheduler designed to guarantee appropriate channel sharing for the various traffic components. We describe some results which highlight how performance depends on the specific operating conditions, as well as on the traffic descriptors of the flows, their reciprocal difference, and performance requirements.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2009년도 추계학술대회 논문집
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• pp.231-232
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• 2009

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.394-394
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• 2001

배출량 산정방법 정의서(환경부, 2000)에서는 점오염원을 제외한 면오염원과 이동오염원에서 배출되는 대기오염물질의 공간할당은 개별 오염원의 배출량을 격자에 배분하여 합산하는 방식을 제시하고 있다. 이때 일반적으로 TM-좌표상에서 1km x 1km로 구성된 격자에 배출량을 할당하게 된다. 국가 전체로 보면 1km x 1km 격자계는 상세정보이지만 대부분의 대기영향평가의 대상범위는 국지규모이므로, 이 경우 1km x 1km 격자 할당방식으로 구성한 배출정보를 사용할 경우 부정확한 예측결과를 가져올 수 있다. (중략)

• Applied Science and Convergence Technology
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• 제26권6호
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• pp.195-200
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• 2017

A mobile lab kart for plasma training is developed with a high vacuum pumping system, vacuum gauges and a glass discharge tube powered by a high voltage transformer connected to a household 60 Hz line. A numerical model is developed by using a commercial multiphysics software package, CFD-ACE+ to analyze the experimental data. Simulations for argon and nitrogen were carried out to provide fundamental discharge characteristics. Variations of the kart configuration were demonstrated: a glass tube with three electric probes, optical emission spectrometer attachment and infra red thermal imaging system to give more detailed analysis of the discharge characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1921-1926
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• 2003

We build a local minimum free motion planning for mobile robots considering dynamic environments by simple sensor fusion assuming that there are unknown obstacles which can be detected only partially at a time by proximity sensors and can be cleaned up or moved slowly (dynamic environments). Potential field is used as a basic platform for the motion planning. To clear local minimum problem, the partial information on the obstacles should be memorized and integrated effectively. Sets of linked line segments (SLLS) are proposed as the integration method. Then robot's target point is replaced by virtual target considering the integrated sensing information. As for the main proximity sensors, we use laser slit emission and simple web camera since the system gives more continuous data information. Also, we use ultrasonic sensors as the auxiliary sensors for simple sensor fusion considering the advantages in that they give exact information about the presence of any obstacle within certain range. By using this sensor fusion, the dynamic environments can be dealt easily. The performance of our algorithm is validated via simulations and experiments.

• 한국환경과학회지
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• 제22권9호
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• pp.1105-1113
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• 2013

This paper attempted to estimate the emissions of HFC-134a from scrap truck as a result of measuring the residual quantities of HFC-134a in air conditioner of scrap truck. We measured the residual amounts in the scrap truck of 138 by applying commercial recover for refrigerants. The average residual rate(disposal-phase emission factor) is reported to be $44.3{\pm}3.3%$ within a confidence interval of 95%. Recent year model trucks exhibit the higher residual rates. Little variation, however, is observed in regard to vehicle size. The HFC-134a emission quantity from scrap truck in 2011 is estimated to be 55,908 $tCO_2$-eq that demonstrates 21.4% increase to compare with that in 2007. As the numbers of truck have increased dramatically during the last two decades, the emissions of HFC-134a from scrap truck would increase sharply in the next coming years. HFC-134a is a very high GWP greenhouse gas. therefore have to reduce the emissions from the scrap truck and need to find ways to recycle. The chemical compositions of refrigerants from scrap truck are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap truck could be reused as refrigerant.