• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.191-199
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• 2002

Pacific oysters Crassostrea gigas (Thunberg) were collected on April, 1999 and March­September, 2000 from Goseung Bay along the southern coast of Korea. The oysters tested cp;;ected from a depth of 0.5-2 m in which they cultured by a long line hanging method. The oxygen consumption rates (OCR) of oysters held under constant temperature and darkness (CC), were determined using an automatic intermittent-flow-respirometer (AIFR). Depending on holding periods after oyster collection, the experiments were divided into two groups: Group 7-d (held to ambient temperature for ca. 7 days) and Group 2l-d (held to ambient temperature for ca. 21 days). The OCR for Group 7-d single oyster displayed two peaks every day under CC, while Group 2l-d single oyster showed one peak every day. It is likely that the rhythmic patterns 02.6-12.8 hours) of the OCR in the Group 7-d single oyster may have been influenced by tidal currents at the sampling site. The rhythmic patterns (24.3-24.7 hours) in the Group 2l-d single oyster may have been shifted from two peaks to one peak each day under CC. The present study concludes that the OCR rhythm of wild oysters in nature is governed by two lunar-day clocks (24.8 hours); one driving one peak and the other driving the second peak. When oysters are subjected to the long-term CC conditions, one of the two-clock systems is depressed or only intermittently becomes active. Jpwever. the OCR rhythms by two to three oysters occurred arrhythmic patterns during the experiments and exhibited some evidence of weak rhythmicity of compared to those of a single oyster. It could be partly due to differences group effects.

• 한국자동차공학회논문집
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• 제25권3호
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• pp.287-296
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• 2017

Although emission regulations have been gradually strengthened in the past decade, the road transport section remains the most important source of NOx emission in air pollution. One reason is that there has been an increase in the proportion of diesel vehicles and in the volume of traffic. In addition, the certification procedure for standard emission limit does not sufficiently reflect real traffic condition and various driving patterns. Therefore, the European Commission(EC) has recently come up with the RDE-LDV(Real driving emissions-light duty vehicle) regulations, and the Ministry of Environment in Korea has been conducting research on evaluating RDE-LDV with PEMS(Portable Emission Measurement Systems). According to the trip requirements of the 2nd RDE package announced by the EC, the objectives of the present study include the development of Korean RDE routes to reflect domestic traffic and road conditions. Based on the results, both RDE routes are in correct compliance with RDE-LDV regulations, including trip requirements and trip dynamics. KOR-NIER Route 1, in particular, has a higher driving load in rural driving with regard to excessive gradient of elevation compared to KOR-NIER Route 2, including relatively plane rural driving.

• 한국도로학회논문집
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• 제12권3호
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• pp.9-16
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• 2010

본 연구는 시뮬레이터를 이용하여 속도감속 노면표시 유형별로 감속 효과가 어느 정도인지에 대한 연구를 수행하였다. 이를 위해서 20~70대의 다양한 연령층으로 구성한 41명이 실험에 참여하였다. 구간별 기법에 따른 속도현황을 살펴보면, 노면표시 시작지점 및 곡선시작점에서 Peripheral Transverse Line II의 속도 감속효과가 가장 좋은 것으로 나타났다. 본 연구는 도로이용자의 인간공학적 고려 요소를 바탕으로 운전자 시각특성을 고려한 감속유도기법 개발에 있어서 그 효과를 검증했다는 점에서 의의가 있다. 향후 연구로는 감속유도 노면표시가 장기적으로 운전자에게 효과적인지에 대한 검증이 필요하며, 색의 대비(예 : 흰색 노면표시에 검은색 아스팔트)에 따른 속도감속 효과가 있는지에 대한 연구도 필요하다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 춘계학술대회 및 임시총회
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• pp.256-259
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• 2002

Recently, most vehicles has the Automatic transmission system as their transmission system. The automatic transmission system operates with fixed shift patterns. In the opposite of manual operation, it is easy and convenient for driving. Though these merit, the system can not evaluate the driver's intension because of usage of firmed shift pattern. Especially, when the load has declination the AT system must operate for engine break effect. Namely, if the vehicle drives on the load of decrease, the acceleration of the vehicle goes to high then. At that time, the shift goes to down position the vehicle has some negative acceleration with the resistance of engine. To consider driver's intension in this case, we must consider both the driving intensity of driver and the status of load. In this paper, we developed flexible automatic transmission system by using the proposed moduled neural networks which can learn the status of the load and driver's intensity As a result, we compare the transmission system using firmed shift pattern and the proposed transmission system and show the good performance in the change of shift position.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권2호
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• pp.140-146
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• 2013

In this paper, we describe a vision sensor-based driving algorithm for indoor automatic guided vehicles (AGVs) that facilitates a path tracking task using two mono cameras for navigation. One camera is mounted on vehicle to observe the environment and to detect markers in front of the vehicle. The other camera is attached so the view is perpendicular to the floor, which compensates for the distance between the wheels and markers. The angle and distance from the center of the two wheels to the center of marker are also obtained using these two cameras. We propose five movement patterns for AGVs to guarantee smooth performance during path tracking: starting, moving straight, pre-turning, left/right turning, and stopping. This driving algorithm based on two vision sensors gives greater flexibility to AGVs, including easy layout change, autonomy, and even economy. The algorithm was validated in an experiment using a two-wheeled mobile robot.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.612-618
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• 2009

Recently the roles of railways about the prevention of global warming caused by greenhouse gases and for low carbon green growth are larger than ever. And the railroad-related research institutions have been active in researching for energy conservation. Especially the urban railroad has been emerged as the best means of transportation compared to the general public transportation systems in punctuality, stability, ecology and etc. In operating the urban railroad system there are various ways for energy savings. In the larger category, One is the hardware aspect according to the structure of the vehicle and the development of control systems. The other is the software aspect which efficient train operation can be made through control of driving patterns and driving diagram. In this paper, there is sense to analyze the result in verifying expectation relation with variable and the use of electric power on this after selecting main variables that can influence to the energy of the train operation in the software aspect. First, after collecting the basic data related to operation(train speed, operating hours, power consumption, the position of stopping station, electrical power system etc.) and according to this, investigating the consumption of the energy of the operation, in the side of energy consumption deducing and analyzing problem, this will be found solutions.

• 한국지능시스템학회논문지
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• 제11권8호
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• pp.709-714
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• 2001

최근 차량의 경우 미리 설정된 쉬프트 패턴에 의해 변속되도록 고안된 자동변속기가 장착되어 있다. 자동변속기는 기존에 운전자가 수동으로 조작하는 방식과 달리, 자동으로 변속되므로 편안하고 편리하지만, 고정된 패턴을 이용해 변속하기 때문에 운전자의 의지를 반영하지 못한다. 운전자의 의지를 반영하기 위해서는 운전자의 성향뿐만 아니라, 차량의 상태도 같이고려해야한다. 이에, 차량의 상태와 운전자의 조작상태를 모듈 화시켜 학습하여 종합적인 운전성향을 판단하고, 반영하여 변속을 결정하고자 한다. 본 논문에서는 모듈화된 신경망을 이용한 운전의지 판단 알고리즘을 자동차의 자동변속기에 적용하여, 기존에 운전자마다 동일하게 적용되던 고정된 패턴에 의해 변속되던 결과와 비교해 봄으로서, 운전자마다 다른 유동적인 운전의지를 반영한 결과가 우수함을 보이고자 한다.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.25-31
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• 2003

There are a lot of factors influencing on the automobile fuel economy such as average speed, average acceleration, acceleration sum per kilometer, and so on. In this study, various driving data were recorded during road tests. The accumulated road test mileage in Seoul metropolitan area is around 1,300 kilometers. The data were analyzed by multivariate statistical techniques including correlation analysis, principal component analysis, and multiple linear regression analysis. The analyzed results show that the average trip time per kilometer is one of the most important factors to fuel consumption and the increase of the average speed is desirable for reducing emissions and fuel consumption.

• 한국철도학회논문집
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• 제2권2호
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• pp.13-20
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• 1999

The vibration signals of driving parts of electric train are distorted its signal patterns due to the impact components, which occurs when wheel passes rail joints. An elimination method of the impact components is investigated using adaptive signal processing technique in this study The result shows that adaptive interference canceling method seems to be more effective than line enhancement technique. The application of adaptive interference canceling method to the signal measured at bogie shows that the extractions of the signals of driving parts of traction motor, reduction gear, and axle bearing are successful. Therefore, only the signals of bogie, which is the place to attach an accelerometer easily, is sufficient for the fault diagnosis and the safety evaluation of electric train. Also, adaptive interference canceling method can be applicable to evaluate the performance of vibration isolation between bogie and car body and to investigate the characteristics of indoor sound.

• 한국해양공학회지
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• 제5권1호
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• pp.55-63
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• 1991

This study is to predict accurately the wave induced current accuring by the radiation stress which acts as the driving force around Nearshore structure. For the wave induced current, the depth integrated and time averaged governing equation of an unsteady nonlinear form is derived from the continuity and momentum equation of an incompressible fluid. Numerical solutions are obtained by a finite difference method for the governing equation. In the vicinity of a structure, computed flow patterns show good agreement with the hydraulic experimental data. The numerical results obtained by neglecting the convective term show a large change of alongshore and offshore current.