• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.689-691
• /
• 2004

Transmission Pricing is the factor of giving locational signal when Genco decides the generation expansion schedule. Therefore, TR-Pricing is influenced to generation expansion schedule. TR-Pricing is composed of three element, loss-cost and congestion-cost and equipment-cost. The main target of this paper is to analyze TR-Pricing's(especially loss-cost) inpact to generation expansion schedule. Then, this paper make a optimal counterproposal to decide the generation expansion schedule.

• Proceedings of the Korea Technology Innovation Society Conference
• /
• 2001.11a
• /
• pp.3-17
• /
• 2001

In this paper, we compare the market performances under circuit pricing whereby users are charged based on their length of usage time and under packet pricing whereby users are charged based on the amount of information received. We show that, if packet pricing is introduced, the market price rises contrary to the government's expectation but that the overall social welfare is unambiguously increased because packet pricing reflects the social cost properly while circuit pricing does not. Also, we show that, if delivery of multi-media files requires a much higher speed, a move to packet pricing lowers the price of multi-media transmission, thereby increasing the usage of multimedia data in the absence of congestion, which may not be the case in the presence of congestion.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.855-857
• /
• 2005

Transmission congestion is one of the Key factor to local market power in competitive electricity markets. Financial transmission rights provide the financial protection to their holders by paying back the congestion cost. However, the market participants who have market power can exacerbate their market power. This paper analyzes the effect of exercising local market power with the rights on the market price. The proposed methodology was demonstrated with the Optimal Power Flow(OPF). Case study is fulfilled by GAMS simulation. The simulation are condusted in case of Nodal Pricing.

• Proceedings of the KIEE Conference
• /
• 2005.11b
• /
• pp.159-161
• /
• 2005

Transmission congestion is one of the key factors to local market power in competitive electricity markets. Financial transmission rights provide the financial protection to their holders by paying back the congestion cost. However, the market participants who have market power can exacerbate their market power. Due to the exacerbated market power, this paper analyzes the mitigation of local market power using Contingent transmission rights on the market price. Contingent transmission rights provide not only the financial protection but also regulative penalty. The proposed methodology was demonstrated with the Optimal Power Flow(OPF).

• Journal of the Korean Operations Research and Management Science Society
• /
• v.32 no.3
• /
• pp.63-80
• /
• 2007

This study is a generalization of 'stable dynamics' recently suggested by Nesterov and de Palma[29]. Stable dynamics is a new model which describes and provides a stable state of congestion in urban transportation networks. In comparison with user equilibrium model that is common in analyzing transportation networks, stable dynamics requires few parameters and is coincident with intuitions and observations on the congestion. Therefore it is expected to be an useful analysis tool for transportation planners. An equilibrium in stable dynamics needs only maximum flow in each arc and Wardrop[33] Principle. In this study, we generalize the stable dynamics into the model with multiple traffic classes. We classify the traffic into the types of vehicle such as cars, buses and trucks. Driving behaviors classified by age, sex and income-level can also be classes. We develop an equilibrium with multiple traffic classes. We can find the equilibrium by solving the well-known network problem, multicommodity minimum cost network flow problem.

• Journal of Korean Society of Transportation
• /
• v.22 no.5
• /
• pp.139-149
• /
• 2004

As the expansion of road capacity has become impractical in many urban areas, congestion pricing has been widely considered as an effective method to reduce urban traffic congestion in recent years. The principal reason is that the congestion pricing may lead the user equilibrium (UE) flow pattern to system optimum (SO) pattern in road network. In the context of network equilibrium, the link tolls according to the marginal cost pricing principle can user an UE flow to a SO pattern. Thus, the pricing method offers an efficient tool for moving toward system optimal traffic conditions on the network. This paper proposes a continuous network design program (CNDP) in network equilibrium condition, in order to find optimal congestion toll for maximizing net economic benefit (NEB). The model could be formulated as a bi-level program with continuous variable(congestion toll) such that the upper level problem is for maximizing the NEB in elastic demand, while the lower level is for describing route choice of road users. The bi-level CNDP is intrinsically nonlinear, non-convex, and hence it might be difficult to solve. So, we suggest a heuristic solution algorithm, which adopt derivative information of link flow with respect to design parameter, or congestion toll. Two example networks are used for test of the model proposed in the paper.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.11
• /
• pp.135-142
• /
• 2010

QoS in the proxy system are under heavy influence from interferences such as congestion, latency, and retransmission. Also, multi-level streaming services affects from temporal synchronization, which lead to degrade the service quality. This paper proposes a new segment-based buffer management mechanism which reduces performance degradation of streaming services and enhances throughput of streaming due to drawbacks of the proxy system. The proposed paper optimizes streaming services by: 1) Use of segment-based buffer management mechanism, 2) Minimization of overhead due to congestion and interference, and 3) Minimization of retransmission due to disconnection and delay. This paper utilizes fuzzy value $\mu$ and cost weight $\omega$ to process the result. The simulation result shows that the proposed mechanism has better performance in buffer cache control rate, average packet loss rate, and delay saving rate with stream relevance metric than the other existing methods of fixed segmentation method, pyramid segmentation method, and skyscraper segmentation method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.10a
• /
• pp.527-531
• /
• 2003

Previous researches on scalability problem of distributed virtual environment (DVE) have been mainly focused on spatial partitioning of area of interest (AOI). Congestion phenomena by avatar groups in AOI have been neglected relatively. However, AOI congestion is highly related to scalability of DVT because it exhausts system resources such as network bandwidth and rendering time, and could be a bar to perform collaboration among participants. In this paper, this will be defined as the problem that must be solved for the realization of the scalable DVE, and a model will be proposed to measure and control congestion situation in AOI. The purposes of the proposed model are to prevent high density of participants in AOI, and to protect stable collaboration in DVE. For evaluation of the performance it is compared with a previous method by defining the resource cost model which is dynamically activated to AOI congestion.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1426-1440
• /
• 2008

In Korea, the concentration for the use of urban railroads is comparatively high during peak hours. In case of road traffic, overcrowdness leads the increase of total travel time and cost naturally but this does not happen in railroad systems because of fixed operational interval. Thus, passenger's disutility is generated physically and mentally from congestion increment. The increase of railroad capacity from new transit lines and expansion of existed lines contributes traveler's comfort benefits to rising. However, present evaluation guidelines for feasibility studies of road and railroad projects do not include any valuation methodology about passenger's comfort benefits. Therefore, in this research, various factors affecting comfort benefits are reviewed and stated preference survey is performed in order to estimate traveler's comfort benefits for congestion reduction. In addition, willingness to pay for congestion avoidance is calculated from that stated preference survey based on Tobit Model. As a result, detailed unit for willingness to pay according to congestion reduction is proposed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.6D
• /
• pp.623-636
• /
• 2012

Roundabout is an intersection that allows vehicles to pass through the intersection by circulating the circular traffic island at the center of the intersection. In this study, a comparative analysis was conducted on roundabout at five locations in order to deduce the operational result and financial effect of roundabout and signal intersection. As for the operational result, it was found that roundabout showed improvement effect in the average delay per vehicle compared to that of signal intersection by minimum of 65.6% and maximum of 91.77%. it was found that roundabout showed financial cost-saving effect in the traffic congestion cost compared to that of signal operation by minimum of 58.59% and maximum of 81.69% per year. It can be known from these analysis results that roundabout has significant operational effects under certain amount of traffic volume by allowing vehicles to pass through the intersection in a continuous way without much waiting time and stoppage from signal control.