• 한국유기농업학회지
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• 제13권2호
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• pp.129-143
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• 2005

Attempting to make an economic valuation of semi-liquid manure raises various complex questions. These are the valuation under different farming conditions, cost-benefit analysis in connection with the investment requirements of different semi-liquid manure systems, different storage capacities, transportation distances and treatment procedures. In the following, there questions will be discussed : 1. What value do the different types of semi-liquid manure have under different farming conditions? 2. Which storage capacities are economically justified? 3. Under which conditions is the transport of semi-liquid manure over long distances profitable?

• 대한교통학회지
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• 제13권3호
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• pp.5-17
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• 1995

One of interesting issues in urban land-use and transportation policy is about an unproven belief that imbalances between employment and residential sites strongly influence urban commuting patterns. The purpose of this study si to find how spatial distribution of jobs and housing affects commuting distances in Seoul Metropolitan Area using 1990 Census O-D Data. This study estimates cost-minimizing required commuting distance, given the actual distributions of jobs and housing , and compares required commuting distances with actual commuting distances. One of findings is that the standard urban economic theory explains only 1/3 of actual commuting in the case study area. The policy implication of this study is that jobs-housing balance policy will have only a minor effect on the actual commuting.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2015년도 추계학술대회
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• pp.109-111
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• 2015

The Arctic transportation offers big opportunities as shorter transport distances, less fuel consumption, less carbon emissions, faster deliveries of goods, and more profits. The present study is aimed to investigate a future flow to deal with policy in arctic transportation using Big data analysis.

• 대한교통학회지
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• 제6권2호
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• pp.49-56
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• 1988

Alternate use of lane at a signalized intersection is a quite different control of the operation of an intersection. This control introduces a new stop line and signal before the original stop line. All of the lanes between the two stop lines are used for left turn traffic or through traffic at a time. The purpose of the control is increasing the capacity of a n intersection without widening the approach width. this paper contains a study on the condition of a application, the proper distances between the two stop lines, the reasonable offsets(rear) to guarantee clearing the vehicles of previous phase, the comparison of approach capacity between the existing control and this control. The study results reveals that the offsets(rear) are rather stable showing the range(maximum value minus minimum value) of it's value does not exceed 3.6 seconds according to the field data. The approach capacity will be increased by 27%, 43%, 59%, 84% when the distances between the stop lines are 30.0m respectively. The control might have theoretical limitation to operate in practice. So an experimental application of the control at some suitable intersections prior to expanding it.

• Advances in nano research
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• 제13권6호
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• pp.587-597
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• 2022

In the present study, a novel optimization method in formation control of multi -system vehicles based on the trajectory of the nearest neighbor trajectory is presented. In this regard, the state equations of each vehicle and multisystem is derived and the optimization scheme based on minimizing the differences between actual positions and desired positions of the vehicles are conducted. This formation control is a position-based decentralized model. The trajectory of the nearest neighbor are optimized based on the current position and state of the vehicle. This approach aids the whole multi-agent system to be optimized on their trajectory. Furthermore, to overcome the cumulative errors and maintain stability in the network a semi-centralized scheme is designed for the purpose of checking vehicle position to its predefined trajectory. The model is implemented in Matlab software and the results for different initial state and different trajectory definition are presented. In addition, to avoid collision avoidance and maintain the distances between vehicles agents at a predefined desired distances. In this regard, a neural fuzzy network is defined to be utilized in conjunction with the control system to avoid collision between vehicles. The outcome reveals that the model has acceptable stability and accuracy.

• 한국안전학회지
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• 제23권6호
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• pp.171-177
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• 2008

As the risk of traffic accidents caused by mists emerged as a social problem, recently safety facilities to be prepared for mists are being actively installed when designing roads. But in some part, the facilities are being installed imprudently without analyzing the extent of occurrences of mists that would increase the risk of traffic accidents and appropriate countermeasures against the occurrences of mists are not being suggested. For that reason, in this study, first questionnaire surveys were executed on road users in order to draw the factors affecting the traffic accidents caused by mists, a mist traffic accident predicting model was developed and an accident seriousness determining model that can determine accident seriousness was developed. In this way, by extracting major factors affecting mist traffic accidents to grasp risk factors in roads to be caused by mists, safety of roads can be enhanced and traffic accidents in road operations can be decreased. As the affecting factors influencing mist traffic accidents, were extracted sightable distances, durations of mists and whether daytime or nighttime as major factors and the plan to install the facilities for the prevention of mist traffic accidents was suggested to prevent the traffic accidents to be caused by those factors and also the plan to operate roads considering sightable distances was suggested to solve the problem of insufficient sightable distances to be caused by mists was suggested. It is judged that the road safety in the areas where mists occur can be improved through foregoing methods.

• Advances in robotics research
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• 제1권2호
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• pp.171-183
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• 2014

Distributed planning and decision making can be beneficial from the robustness, adaptability and fault tolerance in multi-robot systems. Distributed mechanisms have not been employed in three dimensional transportation systems namely aerial and underwater environments. This paper presents a distributed cooperation mechanism on multi robot transportation problem in three dimensional environments. The cooperation mechanism is based on artificial capital market, a newly introduced market based negotiation protocol. In the proposed mechanism contributing in transportation task is defined as asset. Each robot is considered as an investor who decides if he is going to invest on some assets. The decision is made based on environmental constraint including fuel limitation and distances those are modeled as capital and cost. Simulations show effectiveness of the algorithm in terms of robustness, speed and adaptability.

• 대한공간정보학회지
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• 제12권2호
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• pp.73-77
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• 2004

대도시의 도심 정체나 대중교통 장려책과 같은 요소로 인해 대중교통에 대한 관심과 이용도가 증가하고 있다. 그러나 노선의 설계나 배분에 관한 연구가 미흡하고 적절한 정량적인 방법론이 구축되어 있지 않기 때문에 설계, 운영에 어려움을 겪고 있다. 노선의 공급과잉이나 공급부족으로 인해 접근성이 지역간에 편중되어 나타나며, 도시 각 구역의 정류장은 다른 지역으로 이동하는 시간과 비용, 심적 부담에 있어 큰 편차를 보이고 있다. 한편, Space Syntax 이론은 도시공간이나 건축공간의 접근성을 공간의 기하학적인 연결구조에 기반하여 정량적으로 산출하는데 사용되는 이론이다. 본 연구는 Space Syntax 이론을 대중교통 문제에 효과적으로 적용하기 위해 알고리즘을 수정하였으며, GIS를 이용하여 간략한 가상의 네트워크를 구축한 후 이를 적용하는 과정을 예시하였다.

• Korean Journal of Geomatics
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• 제4권2호
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• pp.53-57
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• 2004

Due to the traffic congestion and public-oriented transportation policies of Seoul, public transportation is receiving attention and being used increasingly. However, current transport routes configuration is showing unbalanced accessibility throughout the city area creating differences in time, expenses and metal burden of users who travel the same distances. One of the reasons is that transport route planning has been partially empirical and non-quantitative tasks due to lack of relevant methods for assessing the complexity of the transport routes. This paper presents a method to compute the connectivity of public transport system based on the topological structure of the network of transport routes. The main methodological issue starts from the fact that the more transfers take place, the deeper the connectivity becomes making that area evaluated as less advantageous as for public transport accessibility. By computing the connectivity of each bus or subway station with all others in a city, we can quantify the differences in the serviceability of city areas based on the public transportation. This paper is based on the topological interpretation of the routes network and suggests an algorithm that can automate the computation process. The process is illustrated using a simple artificial network data built in a GIS.

• 한국농공학회논문집
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• 제60권3호
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• pp.51-61
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• 2018

Transportation and storage technologies, which are key drivers for trade, has increased global trade of agricultural products about 165% from 1995 to 2015. Korea imports 76.2% of grain from major food exporters such as USA, Australia, Brazil, and China. The expected long shipping distances from these countries can seriously cause environmental impacts on various environmental categories such as climate change, particulate matter, and acidification. The goal of this study is to assess the environmental implications focused on greenhouse gases (GHGs) and particulate matters (PMs) emissions of imported grains (wheat, corn, and bean) using food miles analysis and life cycle assessment (LCA). The environmental impacts of imported crops are estimated by transportation modes using the national LCI database provided by Korea Environmental Industry & Technology Institute (KEITI). The results of this study are as follows; (1) Imported wheat comes from USA (29%), AUS (27%), and URK (20%), corn is imported from USA (34%), BRA (29%), and URK (16%), and bean comes from BRA (57%), USA (40%), and CHN (2%); (2) the food miles of imported crops (wheat, corn, and bean) are 3.62E+10, 1.30E+11, and $2.20E+10ton{\cdot}km$, respectively; (3) the potential GHGs and PMs of wheat, corn, and bean are 5.02E+08, 1.67E+09, and 2.84E+08 kg $CO_2e$ and 5.89E+05, 1.83E+06, 3.07E+05 kg $PM_{10}e$, respectively. The outputs of this study could provide environmental impacts and carrying distances of imported agricultural products for preparing a plan to reduce environmental impacts.