• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.70-86
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• 2022

An autonomous demand-responsive bus with mobility-on-demand service is an innovative transport compensating for the disadvantages of an autonomous bus and a demand-responsive bus with mobility-on-demand service. However, less attention has been paid to the quantitative impact assessment of the autonomous demand-responsive bus due to the technological complexity of the autonomous demand-responsive bus. This study simulates autonomous demand-responsive bus trips by reinforcement learning on a microscopic traffic simulation to quantify the impact of the autonomous demand-responsive bus. The Chungju campus of the Korea National University of Transportation is selected as a testbed. Simulation results show that the introduction of the autonomous demand-responsive bus can reduce the wait time of passengers, average control delay, and increase the traffic speed compared to the results with fixed route bus service. This study contributes to the quantitative evaluation of the autonomous demand-responsive bus.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.11
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• pp.39-49
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• 2011

Smart Grid has two main objectives on both supply and demand aspects which are to distribute the renewable energy sources on supply side and to develop realtime price responses on demand side. Renewable energy does not consume fossil fuels, therefore it improves the eco-friendliness and saves the cost of power system operation at the same time. Demand response increases the flexibility of the power system by mitigating the fluctuation from renewable energies, and reduces the capacity investment cost by shedding the peak load to off-peak periods. Currently Smart Grid technologies mainly focus on energy monitoring and display services but it has been proved that enabling technologies can induce the higher demand responses through many pilot projects in USA. On this context, this paper provides a price responsive algorithm for HEMS (home energy management system) on the real time pricing environment. This paper identifies the demand response as a core function of HEMS and classifies the demand into 3 categories of fixed, transferable, and realtime responsive loads which are coordinated and operated for the utility maximization or cost minimization with the optimal usage combination of three kinds of demand.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.163-171
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• 2012

Demand Responsive Transit (DRT) services are becoming necessary as part of not only alternative transportation means for elderly and mobility impaired passengers, but also sustainable and flexible transportation options in urban area due to the development of communication technologies and Location Based Services (LBS). It is difficult to investigate the system performance regarding vehicle operational schemes and vehicle routing algorithms due to the lack of commercial software to support door-to-door vehicle simulation for larger area. This study proposes a simulation framework to evaluate innovative and flexible transit systems focusing on various vehicle routing algorithms, which describes data-type requirements for simulating door-to-door service on demand. A simulation framework is applied to compare two vehicle dispatch algorithms, Nearest Vehicle Dispatch (NVD) and Insertion Heuristic (IH) for real-time shared-taxi service in Seoul. System productivity and efficiency of the shared-taxi service are investigated, comparing to the conventional taxi system.

• Advances in Energy Research
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• v.7 no.2
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• pp.85-100
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• 2020

Distributed energy resources (DERs) are essential for coping with growing multiple energy demands. A microgrid (MG) is a small-scale version of the power system which makes possible the integration of DERs as well as achieving maximum demand-side management utilization. Hence, this study focuses on the analysis of optimal power dispatch considering economic aspects in a multi-carrier microgrid (MCMG) with price-responsive loads. This paper proposes a novel time-based demand-side management in order to reshape the load curve, as well as preventing the excessive use of energy in peak hours. In conventional studies, energy consumption is optimized from the perspective of each infrastructure user without considering the interactions. Here, the interaction of energy system infrastructures is considered in the presence of energy storage systems (ESSs), small-scale energy resources (SSERs), and responsive loads. Simulations are performed using GAMS (General Algebraic modeling system) to model MCMG, which are connected to the electricity, natural gas, and district heat networks for supplying multiple energy demands. Results show that the simultaneous operation of various energy carriers, as well as utilization of price-responsive loads, lead to better MCMG performance and decrease operating costs for smart distribution grids. This model is examined on a typical MCMG, and the effectiveness of the proposed model is proven.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.82-96
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• 2020

The Demand Responsive Transit (DRT) system is the flexible public transport service that determines the route and schedule of the service vehicles according to users' requests. With increasing importance of public transport systems in urban areas, the development of stable and fast routing algorithms for DRT has become the goal of many researches over the past decades. In this study, a new heuristic method is proposed to generate fast and efficient routes for multiple vehicles using demand clustering and destination demand priority searching method considering the imbalance of users' origin and destination demands. The proposed algorithm is tested in various demand distribution scenarios including random, concentration and directed cases. The result shows that the proposed method reduce the drop of service ratio due to an increase in demand density and save computation time compared to other algorithms. In addition, compared to other clustering-based algorithms, the walking cost of the passengers is significantly reduced, but the detour time and in-vehicle travel time of the passenger is increased due to the detour burden.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.17-34
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• 2022

This paper develops a model for dynamic station assignment to optimize the Demand Responsive Transit (DRT) operation. In the process of optimization, we use the bus travel time as a variable for DRT management. In addition, walking time, waiting time, and delay due to detour to take other passengers (detour time) are added as optimization variables and entered for each DRT passenger. Based on a network around Anaheim, California, reserved origins and destinations of passengers are assigned to each demand responsive bus, using K-means clustering. We create a model for selecting the dynamic station and bus route and use Non-dominated Sorting Genetic Algorithm-III to analyze seven scenarios composed combination of the variables. The result of the study concluded that if the DRT operation is optimized for the DRT management, then the bus travel time and waiting time should be considered in the optimization. Moreover, it was concluded that the bus travel time, walking time, and detour time are required for the passenger.

• Journal of Korean Society of Rural Planning
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• v.14 no.3
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• pp.27-36
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• 2008

Rapid increase of aging population and progressed migration from rural areas to urban areas have caused deficit of bus routes in local cities. This increasing burden of operation deficit affects the movement strategy of the transportation vulnerable who are using buses. Along with dramatically increased aging in Korea, there is an urgent need to implement a new method which can guarantee mobility rights of public transportation especially for the elderly. This study focuses on the case of Demand Responsive Transit(DRT) system that has been operating in America, Europe, Japan, etc. Kimhae(Sangdong-myeon and Saengnim-myeon) is selected as a study area. This study investigated the possibility of adopting DRT system on the perspectives of the consumer and provider by the analysis of traffic condition such as the number of transportation vehicles, present bus service and regulation and conduct of questionnaire survey which includes present bus service and DRT system and so on. In conclusion, DRT system in Kimhae city will reduce transport cost, increase affordability through the betterment of service level and secure mobility rights for the transportation vulnerable.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.259-260
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• 2021

Currently, the school-age population continues to decline in Korea due to social factors. On the other hand, the dormitory facilities are constantly being built and renovated. There are many problems such as construction period and on-site waste when constructed with reinforced concrete structures, which are existing construction methods. Accordingly, dormitory facilities shall be constructed using appropriate construction methods. Therefore, in this study, we will collect and organize basic data on the use status and modular system of dormitory facilities and study efficient maintenance and management when modular construction method is applied to dormitory facilities with changing demand.

• Journal of Korea Planning Association
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• v.54 no.4
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• pp.71-78
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• 2019

Due to the rapid pace of low fertility and aging of Korea, population decline is rapidly progressing in the outskirts of the province and county. Demand for public transport is decreasing due to suburban population declines, while local government funding for maintenance of the bus system is expected to increase gradually. The government and municipalities are promoting the introduction of Demand Responsive Transport (DRT) in order to reduce the burden of financial support for buses while enhancing mobility of the residents in vulnerable areas. However, most DRTs in Korea have been operated mainly in the areas that are not provided with public transportation services. Although DRT is able to reduce the financial burden of local governments, it is not easy to be introduced because of the objection of the existing bus users. In this study, 11 out of 61 towns with poor public transportation services in Gyeongsangnam-Do were selected for the introduction of DRT to replace bus services by using village characteristics. The results of this study are expected to be used as a basis for decision making to use DRT instead of bus service for the burden of bus financing for local governments.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.103-111
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• 2015

The purpose of this study is to estimate the appropriate Demand Responsive Transport (DRT) fare for bus users upon introduction of the system, which is to improve ridership on economically non-profitable routes and to conform to the mobility right of those living in presently non-serviced rural areas. For this, a stated preference (SP) survey was adopted to assess respondents' preferences regarding DRT introduction, while the contingent valuation method (CVM) was used to calculate their willingness to pay (WTP) for DRT services. The analysis results show that, compared to the existing bus services with a 1,000 won bus fare, the value of DRT is considered to be 38.85%, 31.03% and 30.12% higher in terms of overall assessment, usability and convenience, respectively. The results of this study are expected to facilitate the decision making aimed at setting the appropriate DRT fare and implementing a DRT system that meets sustainability requirements.