• Proceedings of the Technology Innovation Conference
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• 2002.06a
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• pp.181-200
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• 2002

최근 급진전되고 있는 인터넷의 광대역화와 다양한 멀티미디어 컨텐츠의 수요확대 그리고 인터넷 이용자의 급증 등으로 인터넷 트래픽은 기하급수적으로 증가하고 있다. 그러나 최선형 패킷교환방식인 현 인터넷은 급증하는 네트워크 수요를 감당하기에 이미 기술적 한계를 드러내고 있을 뿐 아니라, 네트워크 확장을 통하여 급증하는 트래픽을 수용하는 것도 경제적으로 한계수위에 도달하고 있다. 따라서 네트워크 수요 대비 공급량의 불균형으로 인터넷망에서의 혼잡(congestion)문제가 점차 중요한 이슈로 제기되고 있으며, 이런 문제의 해결방안으로 네트워크공급을 늘리거나, 초과수요를 줄이는 방안에 대한 논의와 구체적인 노력이 이루어지고 있다. 이에 본 고에서는 간단한 기술 경제학적 모형을 이용하여 혼잡의 원인과 이에 대한 해결방향에 대하여 분석적인 설명을 시도하였다. 특히 본 고에서는 인터넷 혼잡의 원인이 '부정적 네트워크 외부성' 이 존재하기 때문이며, 실무적으로 혼잡문제 해결의 대표적인 대안으로 적용되고 있는 네트워크의 용량확대는 혼잡해결의 근본적인 대안이 되지 못하고, 반면 실무적으로 별로 주목받고 있지 않는 네트워크 투자를 최소화하고 트래픽을 통제할 수 있는 '혼잡세'를 부과할 수 있는 요금제 도입이 효율적인 혼잡 해결방안 임을 밝히고 있다.

• Proceedings of the KIEE Conference
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• summer
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• pp.737-739
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• 2004

The domestic power system established with Cost-Based-Pricing(CBP) from April 2001. The system is a uniform pricing system. System Operator(50) establishes a Price Setting Schedule by the prediction of consumption and the presented bid price(generation cost) of the generation utility. But the Price Setting Schedule doesn't take account of the constraint of the system. This cause a transmission congestion, constrained-on generation and constrained-off generation. This Paper search the way of the increasing efficiency of domestic power system through the redemption of congestion charge.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.134-138
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• 1998

Because of the statistical fluctuations and the high 'time-variability' nature of the traffic, managing the resources of the network require highly dynamic techniques with minimal Intervention and reaction times, and adaptive and learning capabilities. The neural networks normalizes the ATM cell arrival rate and queue length and has the adaptive learning algorithm, and experimentally investigated the method to prevent the congestion generated in ATM networks.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.610-615
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• 2003

With the growing competitive pressure from market participants, utilities, consumer and government, analyses of existing competitive electricity market become more important. The presence of congestion in the transmission system can significantly increase the potential of exercising market power. Since the congestion in the network depends on the several factors, the market power cannot be simply analyzed through the existing indices. This paper presents a systematic analysis on local market power under uniform pricing scheme and provides determining approach of the level of price cap as mitigation measure of the strategic market power.

• Journal of the Korean Regional Science Association
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• v.14 no.1
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• pp.1-20
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• 1998

In this paper, the authors studied a comprehensive study of national physical distribution costs used here was originally developed by J. L. Heskett(1962) and modified in Korean context by Oh-Kyung Kwon(1997). Using this method the authors calculated national physical distribution costs in Korea from 1984 to 1996. Unlke the major industrialized countries, national physical distribution costs in Korea showed continuous increasing trend in every senses. Using this time series data on physical distribution costs, we analysis the inefficiencies in the physical distribution and figured out the sources of these inefficiencies. The major sources of increasing physical distribution costs in Korea were (1) increasing traffic congestion measured by number of automobiles per road-kilometer, (2) increasing real wages, and (3) high interest rates. Especially, alternatives adopted by firms facing increasing traffic congestion were buying more vehicles, which in turn caused more serious congestion ever. This inefficient cycle in physical distribution area should be cut somehow in order to restore national competitiveness of Korean frims by reducing physical distributins costs.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.19-25
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• 2006

As metropolitan areas are rapidly growing in both a lot of population and traffic volume, it causes traffic congestion. Generally, High Occupancy Vehicle (HOV) lanes may increase the efficiency of road usage. The main contribution in this paper is to provide the scientific attempt to measure the effectiveness with regard to HOV lanes adaptation using an Integration simulation tool in order to alleviate the traffic congestion in Olympic highway.

• Journal of information and communication convergence engineering
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• v.2 no.1
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• pp.15-21
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• 2004

One of the most important issues in designing a network and realizing a service is dealing with traffic characteristics. Recent experimental research on LAN, WAN, and VBR traffic properties has highlighted that real traffic specificities can not be displayed because the current models based on the Poisson assumption under estimate the long range dependency of network traffic and self-similar peculiarities. Therefore, a new approach using self-similarity characteristics as a real traffic model was recently developed. In This paper we discusses the definition of self-similarity traffic. Moreover, real traffic was collected and we generated self-similar data traffic like real traffic to background load. On the existing ABR congestion control algorithm transmission throughput with the representative ERICA, EPRCA and NIST switch algorithm show the efficient reaction about the burst traffic.

• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.357-368
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• 2014

So far, land use-transportation models have been used exclusively for numerical analysis. A recent theoretical endeavor now enables us to derive the first-order derivative of the model's welfare function with respect to policy variables. I extend this methodology into the institutional setting where toll revenues are recycled through labor income tax. In this setting, the first-order derivative is composed of (1) the increase in welfare due to reduced congestion, and (2) the decrease in welfare due to interaction with the existing labor income tax. This result coincides with existing theory in the non-spatial model.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.8
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• pp.388-394
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• 2001

This paper presents how to determine the optimal operating points of Unified Power Flow controllers (UPFC) the line flow control of which can enhance system security level. In order to analyze the effect of these devices on the power system, the decoupled model has been employed as a mathematical model of UPFC for power flow analysis. The security index that indicates the level of congestion of transmission line has been proposed and minimized by iterative method. The sensitivity of objective function for control variables of and UPFC has been derived, and it represents the change in the security index for a given set of changes in real power outputs of UPFC. The proposed algorithm with sensitivity analysis gives the optimal set of operating points of multiple UPECs that reduces the index or increases the security margin and Marquart method has been adopted as an optimization method because of stable convergence. The algorithm is verified by the 10-unit 39-bus New England system that includes multiple FACTS devices. The simulation results show that the power flow congestion can be relieved in normal state and the security margin can be guaranteed even in a fault condition by the cooperative operation of multiple UPECs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2796-2813
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• 2014

This paper presents a new algorithm called the adaptive logarithmic increase and adaptive decrease algorithm (A-LIAD), which mainly addresses the Round-Trip Time (RTT) fairness problem in satellite networks with a very high propagation delay as an alternative to the current TCP congestion control algorithm. We defined a new increasing function in the fashion of a logarithm depending on the increasing factor ${\alpha}$, which is different from the other logarithmic increase algorithm adopting a fixed value of ${\alpha}$ = 2 leading to a binary increase. In A-LIAD, the ${\alpha}$ value is derived in the RTT function through the analysis. With the modification of the increasing function applied for the congestion avoidance phase, a hybrid scheme is also presented for the slow start phase. From this hybrid scheme, we can avoid an overshooting problem during a slow start phase even without a SACK option. To verify the feasibility of the algorithm for deployment in a high-speed and long-distance network, several aspects are evaluated through an NS-2 simulation. We performed simulations for intra- and interfairness as well as utilization in different conditions of varying RTT, bandwidth, and PER. From these simulations, we showed that although A-LIAD is not the best in all aspects, it provides a competitive performance in almost all aspects, especially in the start-up and packet loss impact, and thus can be an alternative TCP congestion control algorithm for high BDP networks including a satellite network.