• 대한교통학회지
• /
• 제8권1호
• /
• pp.25-40
• /
• 1990

This study was undertaken to develop a traffic signal timing method for interconnected and semi-protected-left-turn intersections(the intersections which have left-turn signal but not exclusive left-turn lanes) on four-lane streets for energy saving and to computerize the method for the practical use. For this study, a probability model which could estimate the utilized time of the shared left-turn lane by through traffic during green period was developed based on field studies. The two left-turn treatments, leading and lagging left-turns, were tested for the intersections, and it can be concluded that the leading left-turn was more efficient for the normal urban streets on which through traffic is major traffic. Adopting the leading left-turn macro-models to estimate vehicular average delay and proportions of vehicles stopped at the intersections were developed. Using the two models as well as the idling fuel consumpution rate and the excess fuel consumption per stop-go speed change, a traffic signal timing method for the intersections for energy saving was developed and computerized. The method can be used for more than four-lane streets and for other measures of effectiveness such as minimum delay, minimum stop rates, etc.

• 대한교통학회지
• /
• 제5권2호
• /
• pp.19-35
• /
• 1987

Transportation energy saving is a national concern because all national petroleum energy is imported. A number of intersections are operating as semi-protected intersections, which have left-turn signal but not exclusive left-turn lanes, because of limited roadways in urban areas. Since the traffic signal methods for the intersections having left-turn signal/lanes cannot be applied to the semi-protected intersection, it is needed to develop a new technique. The purpose of this study was to develop a traffic signal timing method at semi-protected intersections for energy saving and to computerize the method for the practical use. A probability model which could estimate left-turn utilization factors of through traffic during green signal was developed based on field studies. Employing the factors, macro-models to estimate vehicular average delay and proportions of vehicles stopped at the semiprotected intersections were developed. The calculated values of the delay model agreed well with the simulated values of a simulation model using SLAM Ⅱ, a simulation language. Using the two models and the idling fuel consumption rate and the excess fuel consumption per stop-go speed change of vehicles. a traffic signal timing method at semi-protected intersections for energy saving was developed and computerized. The method can be used for other measures of effectiveness such as minimum delay, minimum stop ratio, etc.

• 대한전자공학회논문지SD
• /
• 제49권5호
• /
• pp.37-42
• /
• 2012

기존의 전류 스티어링 전하 펌프의 타이밍 부정합 감소를 위한 새로운 전하 펌프를 제안한다. 기존의 전류 스티어링 전하 펌프는 UP, DOWN 신호의 입력단에 NMOS를 사용하여 서로 다른 지연단 수를 갖게 된다. 제안한 전하 펌프에서는 DOWN 신호의 입력단에 PMOS를 사용함으로써 UP, DOWN 신호의 지연단 수를 동등하게 한다. 기존의 전류 스티어링 전하 펌프를 최적화하여 시뮬레이션한 결과 턴온과 턴오프에 대하여 지연시간의 차이는 각각 14ns, 6ns 이다. 반면에 제안한 전하 펌프는 타이밍 부정합이 향상되어 턴온과 턴오프에 대하여 지연시간의 차이는 각각 6ns, 5ns 이다. 타이밍 부정합의 감소로 인하여 기준 스퍼는 -26dBc에서 -39dBc로 줄어들었다. 제안하는 전하 펌프는 CMOS $0.18{\mu}m$ 공정을 사용하여 설계하였다. 측정 결과 전하 펌프 출력 전압 범위 0.3~1.5V에서 최대 1.5%의 전류 부정합을 보인다.

• 농촌지도와개발
• /
• 제11권1호
• /
• pp.53-65
• /
• 2004

The purposes for this study was to provide information for developing educational programs for U-turn farmers' based on their needs on rural settlement. Special objectives of the study were; 1) to survey the general characteristics of U-turn farmers including motives. preparation, and education, 2) to investigate problems and difficulties of the U-turn farmers in rural settlement 3) to identify the reasons for success and failure in U-turn filming, and 4) to provide information in developing programs for U-turn farmers. Data for the study were collected from 526 U-turn farmers throughout the country, and after data cleaning, 494 questionnaires were used for data analysis. Based on the results of this study, the following were recommended for further development of U-turn farming programs; 1) to facilitate and expand continuous surveys on the motives. preparation, education and information for U-turn farmers will be neceassary to update the important and current information on U-turn farming. 2) Further examination of the problems and difficulties of U-turn farmers would be necessary to develop appropriate policies and educational programs for U-turn farming. 3) continuous investigations on the reasons for success and failure of U-turn farming would be necessary to develop appropriate apicultural policies. 4) for more effective educational programs for U-turn farmers. selection of educators, institution, curricular and timing etc. Should be carefully designed to meet the practical needs of the U-turn farmers. 5) more research activities should be encouraged to improve program development and implementation of U-turn farming.

• 한국자동차공학회논문집
• /
• 제20권2호
• /
• pp.30-37
• /
• 2012

Pneumatic Active Engine Mount(PAEM) with open-loop control system has been developed to reduce the transmission of the idle-shake vibration induced by engine effectively and economically. A solenoid valve installed between PAEM and vacuum tank is on-off switched by the Pulse Width Modulate(PWM) control signal to decrease the dynamic stiffness of the engine mount. This paper presents the methodology to identify the optimal values of control parameters of a PAEM, i.e, turn-on timing and duty ratio of PWM signal for 6 different idle driving conditions. A scanning algorithm was first applied to the vehicle test to obtain the approximate optimal control parameters minimizing the vibration at front seat rail and at steering wheel. Then the PAEM system identification was fulfilled to find accurate optimal control parameters by using multi-layer neural networks of Levenberg-Marquardt algorithm with vehicle test data.

• 한국작물학회지
• /
• 제51권1호
• /
• pp.1-13
• /
• 2006

Response of grain yield and milled-rice protein content to nitrogen topdress (N) timing at panicle initiation stage (PIS) is critical for quantifying real-time N requirement for target grain yield and milled-rice protein content. Two split-split-plot experiments with three replications, one in 2004 and the other in 2005, were conducted in Experimental Farm, Seoul National University, Suwon, Korea. The experiments included three N rates at tillering stage (TS), three N timing treatments at panicle initiation stage (PIS) and two rice cultivars. The N rates at TS, N timing at PIS, and rice cultivars were randomly assigned to main plot, sub plot, and sub-sub plot, respectively. Results showed that the delayed N application at PIS reduced grain yield in 2004 and increased milled-rice protein content in both years significantly at 0.05 probability level. The calculated optimum N timing at PIS from pooled data by N rates and rice cultivars in two years was at 28 days before heading (DBH). However, real-time of N timing at PIS was dependent on plant growth and N status around PIS that in turn was dependent on applied N rates at TS. The optimum N timing at PIS was at 30 DBH for no N treatments at TS while at 27 DBH for 3.6 and 7.2 kg N/10a treatments and at 27 and 29 DBH for Hwaseongbyeo and Daeanbyeo, respectively. In general, earlier applied N at PIS resulted in lower milled-rice protein content but the highest grain yield was expected to be obtained when N topdress at PIS was applied at the time when shoot N concentration started to drop below about 23 mg/g due to dilution effect after transplanting. In conclusion, the results of our experiments imply that the currently recommended N topdress time (24DBH) at PIS in Korea should be reconsidered for the higher grain yield and the better quality of rice.

• 한국자동차공학회논문집
• /
• 제14권4호
• /
• pp.20-25
• /
• 2006

Recently, there has been an interest in premixed diesel engines as it has the potential of achieving a more homogeneous and leaner mixture close to TDC compared to conventional diesel engines. Early studies are shown that in a HCCI(Homogeneous Charge Compression Ignition) engine, the fuel injection timing and injection angle affects the mixture formations. Thus the purpose of this study was to investigate relationship of combustion and mixture formations according to injection timing and injection angle in a common rail direct injection type HCCI engine using a early injection method called the PCCI(Premixed Charge Compression Ignition). From this study, we found that the fuel. injection timing and injection angle affect the mixture formations and in turn affects combustion in the PCCI engine.

• 한국ITS학회 논문지
• /
• 제14권1호
• /
• pp.13-21
• /
• 2015

본 연구에서는 두 가지 형태의 공용차로 운영 효율성에 초점을 맞추어 분석을 수행하였다. 직진 우회전 공용차로의 경우 인접한 직진차로에 비해 이용률이 현저히 떨어지는 것으로 나타났으며 그로 인해 신호운영의 효율성이 떨어지는 것으로 분석되었다. 이를 개선하기 위해서는 우선 차로별 교통량 수집을 통한 보다 정교한 신호최적화가 필요하다 할 수 있으며, 나아가 운전자 교육, 홍보를 통해 공용차로의 이용률을 제고하여야 할 것이다. 좌회전 유턴 공용차로에서는 유턴 교통량에 대한 대향 우회전 교통량 비율에 따라 포화교통류율이 감소한다는 것을 확인할 수 있었다. 하지만 유턴, 우회전 차량간 간섭에 따른 현실적인 포화교통류율 보정치를 개발하기 위해서는 차량간 간섭이 일어날 가능성에 대한 확률모형의 정립이 필요한 것으로 판단된다.

• 대한기계학회논문집
• /
• 제18권2호
• /
• pp.397-404
• /
• 1994

Smoke is emitted in diesel engines because fuel injected into the high-temperatured and high-pressured combustion chamber burns with its mixture with insufficient oxygeny. In consideration of air pollution, above all, it is necessary to illuminate the cause of smoke emission in diesel engines. The smoke emission, which is characteristic of diffusion combustion in diesel engines, results from pyrolysis of fuel not mixed with air. Therefore the smoke emission is dependent on diffusion combustion quantity, which is in turn controlled by engine parameter. The study aims at making clear and interpreting the interdependence of smoke emission in diesel engines with heat released within combustion chamber, camparing diffusion combustion quantity according to each engine parameter (air fuel ratio, injection timing, and engine speed), and showing the relation between smoke emission and fraction of diffusion combustion through experiment.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제13권1호
• /
• pp.65-70
• /
• 2013

A 0.18-${\mu}m$ 3.3 V grounded-gate NMOS (GGNMOS) I/O cell array for timing controller (TCON) application is proposed for improving electrical overstress (EOS) robustness. The improved cell array consists of 20 GGNMOS, 4 inserted well taps, 2 end-well taps and shallow trench isolation (STI). Technology computer-aided design (TCAD) simulation results show that the inserted well taps and extended drain contact gate spacing (DCGS) is effective in preventing EOS failure, e.g. local burnout. Thermodynamic models for device simulation enable us to obtain lattice temperature distributions inside the cells. The peak value of the maximum lattice temperature in the improved GGNMOS cell array is lower than that in a conventional GGNMOS cell array. The inserted well taps also improve the uniformity of turn-on of GGNMOS cells. EOS test results show the validity of the simulation results on improvement of EOS robustness of the new GGNMOS I/O cell array.