• The Journal of Asian Finance, Economics and Business
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• v.9 no.4
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• pp.315-324
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• 2022

The goal of this study is to understand better the relationship between hospital bed occupancy rate and cost rigidity as a proxy for the degree of hospital bed congestion, as well as the relationship between the risk of changes in hospital bed occupancy rate and congestion cost, targeting public hospitals. As public hospitals for analysis, we selected hospital projects from the Public Enterprises Survey Reports published by the Department of Public Enterprises, Ministry of Finance, and obtained unbalanced panel data consisting of 1,505 hospitals and 15 years, totaling 12,595 hospitals and years. The analysis revealed that the risk of changes in the bed occupancy rate increases the degree of cost rigidity and leads to a decrease in the variable cost ratio; furthermore, an increase in the bed occupancy rate decreases the degree of cost rigidity and leads to an increase in the variable cost ratio. These findings suggest that although public hospitals are taking managerial actions to avoid congestion costs, congestion costs resulting from higher bed occupancy rates have not been eliminated. The regression analysis results show that even if congestion costs arise as the occupancy rate increases, they are covered by the increase in revenue associated with the increase in the occupancy rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.49-58
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• 2006

The purpose of this study is to develop transportation-sensitive land use densities in a metropolitan context. It analyses traffic impacts according to 20 different development density scenarios in the downtown Seoul, and estimates the density ceiling. The results identify that the transportation-wise sustainable density in the downtown can be extended up to the FAR level of 460% with an option of 2,000 won congestion charge levied on the downtown area. It also finds that the region-wide sustainability measured by congestion level can be improving as the level of congestion charge increases. Without the congestion charge, however, the density ceiling slides down to 430%. It is recommended that, in order to bring in higher density developments in the region, transportation demand management (TDM) measures are indispensible.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.3 s.110
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• pp.56-64
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• 2005

Despite there have been m?my studies about the relationships between congestions and satisfaction in outdoor recreation field, the results indicated only weak impacts of congestions on the satisfaction. This study thus aims to investigate the influence of waiting situation on the whole valuation and satisfaction of guests at theme parks using new variables such as 'goal attainment' and then to suggest implications for waiting management. This study shows meaningful theoretical implications. First, congestion influences the satisfaction more strongly when it prevents guests from achieving their plan. Second, management of waiting time is important and the can be controlled well. When guests have something interested during the waiting time, they were satisfied with the quality of waiting time and overall experience in the theme park.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.81-94
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• 2012

This paper suggests PARED algorithm, a modified RED algorithm, that actively reacts to dynamic changes in network to apply packet drop probability flexibly. The main idea of PARED algorithm is that it compares the target queue length to the average queue length which is the criterion of changes in packet drop probability and feeds the gap into packet drop probability. That is, when the difference between the average queue length and the target queue length is great, it reflects as much as the difference in packet drop probability, and reflects little when the difference is little. By doing so, packet drop probability could be actively controled and effectively dealt with in the network traffic situation. To evaluate the performance of the suggested algorithm, we conducted simulations by changing network traffic into a dynamic stat. At the experiments, the suggested algorithm was compared to the existing RED one and then to ARED one that provided the basic idea for this algorithm. The results proved that the suggested PARED algorithm is superior to the existing algorithms.

• Transportation Technology and Policy
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• v.7 no.5
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• pp.125-132
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• 2010

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.37-40
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• 2000

Multi Protocol Label Switching (MPLS) is a high performance method for forwarding packets (frames) through a network. It enables routers at the edge of a network to apply simple labels to packets (frames). we use MPLS in the core network for internet. MPLS provide high speed switching and traffic engineering in MPLS domain but at the Label Edge Router(LER) there is frequently cell discarding via congestion and buffer management method. It is one of the most important reasons retransmission and congestion. In this paper we propose advanced LER scheme that provide less cell loss rate also efficient network infrastructure.

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.501-512
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• 2012

Social welfare maximization in a double-sided auction market is performed by implementing an aggregation-based particle swarm optimization (CAPSO) algorithm for optimal placement and sizing of one Static Synchronous Series Compensator (SSSC) device. Dallied simulation results (without/with line flow constraints and without/with SSSC) are generated to demonstrate the impact of SSSC on the congestion levels of the modified IEEE 14-bus test system. The proposed CAPSO algorithm employs conventional quadratic smooth and augmented quadratic nonsmooth generator cost curves with sine components to improve the accurate of the model by incorporating the valve loading effects. CAPSO also employs quadratic smooth consumer benefit functions. The proposed approach relies on particle swarm optimization to capture the near-optimal GenCos and DisCos, as well as the location and rating of SSSC while the Newton based load flow solution minimizes the mismatch equations. Simulation results of the proposed CAPSO algorithm are compared to solutions obtained by sequential quadratic programming (SQP) and a recently implemented Fuzzy based genetic algorithm (Fuzzy-GA). The main contributions are inclusion of customer benefit in the congestion management objective function, consideration of nonsmooth generator characteristics and the utilization of a coordinated aggregation-based PSO for locating/sizing of SSSC.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.4
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• pp.123-138
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• 2009

This study examined the first- and second-best pricing by stable dynamics in congested transportation networks. Stable dynamics, suggested by Nesterov and de Palma (2003), is a new model which describes and provides a stable state of congestion in urban transportation networks. The first-best pricing in user equilibrium models introduces user-equilibrium in the system-equilibrium by tolling the difference between the marginal social cost and the marginal private cost on each link. Nevertheless, the second-best pricing, which levies the toll on some, but not all, links, is relevant from the practical point of view. In comparison with the user equilibrium model, the stable dynamic model provides a solution equivalent to system-equilibrium if it is focused on link flows. Therefore the toll interval on each link, which keeps up the system-equilibrium, is more meaningful than the first-best pricing. In addition, the second-best pricing in stable dynamic models is the same as the first-best pricing since the toll interval is separately given by each link. As an effect of congestion pricing in stable dynamic models, we can remove the inefficiency of the network with inefficient Braess links by levying a toll on the Braess link. We present a numerical example applied to the network with 6 nodes and 9 links, including 2 Braess links.

• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.399-406
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• 2000

There are sendee_based research and receiver_based research for dynamic adaptation to network congestion which arises from multicast video conference ; the former results in bandwidth waste of receivers who use high available bandwidth on account of average loss rate in transmission rate, the latter in short of the method that divides layers of available bandwidth of receivers dynamically. In order to do so, in this paper, we established two multicast groups divided into non-congestion status and congestion status according to receiver's network state, and implemented the bandwidth management algorithm which is designed for providing receivers with profitable qualities for available bandwidth by letting them choose each group dynamically in reference to loss rate. As a result, experiments proved that bandwidth waste problem was improved by receiver's dynamic choice according to loss rate.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.513-522
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• 2016

We propose a mechanism for monitoring load in quality of service (QoS)-enabled wireless networks and show how it can be used for network management as well as for dynamic pricing. Mobile network traffic, especially video, has grown exponentially over the last few years and it is anticipated that this trend will continue into the future. Driving factors include the availability of new affordable, smart devices, such as smart-phones and tablets, together with the expectation of high quality user experience for video as one would obtain at home. Although new technologies such as long term evolution (LTE) are expected to help satisfy this demand, the fact is that several other mechanisms will be needed to manage overload and congestion in the network. Therefore, the efficient management of the expected huge data traffic demands is critical if operators are to maintain acceptable service quality while making a profit. In the current work, we address this issue by first investigating how the network load can be accurately monitored and then we show how this load metric can then be used to provide creative pricing plans. In addition, we describe its applications to features like traffic offloading and user satisfaction tracking.