• Journal of Advanced Navigation Technology
• /
• v.14 no.2
• /
• pp.253-259
• /
• 2010

Wireless mesh network is flexible network like Ad hoc network or bluetooth together based on base station. But, wireless mesh network shows high packet loss and when TCP was created, however as it was design based on wired link, wireless link made more transmission error than wired link. It is existent problem of TCP congestion control algorithm that TCP unfairness and congestion collapse over wireless mesh network. When TCP operation occurs with the packet loss where is not the congestion loss, it brings the performance degradation which is serious. In this paper, in order to improve efficient TCP congestion control algorithm in wireless mesh network, we proposed that TCP can adaptively regulate the congestion window in wireless link.

• KIEE International Transactions on Power Engineering
• /
• v.5A no.4
• /
• pp.371-377
• /
• 2005

Congestion problems of transmission lines are very important research issues in power system operations. Load curtailment is one of the ways to solve congestion problems by a major contingency. A systematic and effective mechanism for load shedding has been developed by investigating congestion distribution factors and the direct load control program. In this paper, a load shedding algorithm using linear programming for congestion problems by a major contingency is presented. In order to show the effectiveness of the proposed algorithm, it has been tested on the 6-bus sample system and the power system of Korea, and their results are presented.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.8
• /
• pp.331-339
• /
• 2003

In this paper, we propose an modified TCP congestion control algorithm using estimated RTT with congestion window parameter CWnd. Congestion window size is controlled with memorized RTT value on the congestion status. It can avoid occurrence of frequent congestion and reduce CWnd fluctuation. From simulation results, proposed algorithm shows great improvement on network efficiency and buffer utilization compared with original TCP algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.8A
• /
• pp.1177-1185
• /
• 2000

In this paper, We report on the performance issues faced by TCP based applications on satellite link having long propagation delay and high probability of bit erros and propose ENA(Error Notification Ack) algorithm for TCP Performance Enhancement. TCP Protocol cannot distinguish errored segments(in noisy medium) from losses of genuine network congestion and react as if there is network congestion. Therefore, Slow Start and Congestion avoidance mechanism are initiated. It happen this case in satellite link. Therefore it reduce the transmission rate and drop the performance. So, in this paper We propose ENA algorithm which is distinguished errored segments from losses of network congestion. And We propose the method of algorithm's implementation. And We evaluate the Performance of Tahoe, Reno, Sack TCP with ENA. As results, TCP Performance is better.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.5B
• /
• pp.427-434
• /
• 2003

This paper suggests an improved TCP congestion algorithm, which is more robust to lossy wireless environment than other algorithms such as TCP-Reno. The suggested algorithm decides on the size of a congestion window depending on both PER (Packet Error Rate) and its state, which is one of fast recovery state and slow start state. Some simulations are given to validate the suggested algorithm and the algorithm is compared with other TCP congestion algorithm from the point of view of performance measures such as a congestion window and throughput. The suggested algorithm has better throughput than other algorithm over wireless links with high PER and similar throughput to others over wireless links with low BER.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.474-479
• /
• 2004

This paper describes a feedback-based congestion control algorithm to improve TCP performance over wireless network. In this paper, we adjust the packet marking probability at the router for Max-Min fair sharing of the bandwidth and full utilization of the link. Using the successive ECN (Explicit Congestion Notification), the proposed algorithm regulates the window size to avoid the congestion and sees the packet loss only due to the wireless link error. Based on the asymptotic analysis, it is shown that the proposed algorithm guarantees the QoS of the wireless TCP. The effectiveness of the proposed algorithm is demonstrated by simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.9
• /
• pp.4342-4366
• /
• 2016

Congestion control in Cluster Wireless Sensor Networks (CWSNs) has drawn widespread attention and research interests. The increasing number of nodes and scale of networks cause more complex congestion control and management. Active Queue Management (AQM) is one of the major congestion control approaches in CWSNs, and Random Early Detection (RED) algorithm is commonly used to achieve high utilization in AQM. However, traditional RED algorithm depends exclusively on source-side control, which is insufficient to maintain efficiency and state stability. Specifically, when congestion occurs, deficiency of feedback will hinder the instability of the system. In this paper, we adopt the Additive-Increase Multiplicative-Decrease (AIMD) adjustment scheme and propose an improved RED algorithm by using neighbor feedback and scheduling scheme. The congestion control model is presented, which is a linear system with a non-linear feedback, and modeled by Lur'e type system. In the context of delayed Lur'e dynamical network, we adopt the concept of cluster synchronization and show that the congestion controlled system is able to achieve cluster synchronization. Sufficient conditions are derived by applying Lyapunov-Krasovskii functionals. Numerical examples are investigated to validate the effectiveness of the congestion control algorithm and the stability of the network.

• International Journal of Reliability and Applications
• /
• v.3 no.2
• /
• pp.99-112
• /
• 2002

Traffic congestion is one of critical factors in Internet applications to guarantee their QoS and provide reliable services. This paper discusses many existing congestion control algorithms and proposes a new ISDA. The algorithm is analyzed in respect of queue length, throughput and fairness. The proposed algorithm is working well with TCP and UDP traffics to offer QoS guarantee and fairness.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.4
• /
• pp.603-609
• /
• 1987

In this paper, the single-row routing algorithm for munimizing the street congestion and reducing the between node congestion is deviced. To reduce the between node congestion, reference line crossing is defined and used. Reducing the number of total reference line crossing means reducing the total length which help reduce the power consumption of the integrated system and reducing the between node congestin which help reduce the wiring area. This algorithm has been implemented and tested with various example, then produced good results.

• Journal of the Korean Society for Railway
• /
• v.18 no.3
• /
• pp.270-277
• /
• 2015

In some sections of the Seoul Metropolitan Subway, severe congestion can be observed during rush hours and on specific days. The subway operators have been conducting regular surveys to measure the level of congestion on trains: the results are then used to make plans for congestion reduction. However, the survey has so far focused just on train' congestion and has been unable to determine non-recurring congestion due to special events. This study develops an algorithm to estimate the platform congestion rate by time using individual public transportation card data. The algorithm is evaluated by comparison of the estimated congestion rate and the ground truth data that are actually observed at non-transfer subway stations on Seoul subway line 2. The error rates are within ${pm}2%$ and the performance of the algorithm is fairly good. However, varying walking times from gates to platforms, which are applied to both non-peak periods and peak time periods, are needed to improve the algorithm.