• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.490-501
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• 1994

In this study the problems of cell marking method used in the field of ATM network traffic control are presented. Also an extended cell marking method considering the user level priority is proposed. The conventional traffic monitoring schemes set the CLP bit of a cell to 1 only under the circumstance of the violation of traffic contract. It causes that the number of low level cells increases and the levels of cells are lowered regardless of the user level priority. The three level priority control method combining FCI bit with CLP bit has also been proposed. It divides CLP=0 cells into two levels. Consequently, the proposed method preserves more cells in high level than the conventional one and the real loss of high level cells can be reduced. The performance of the proposed scheme has also been analyzed by the PBS(partial buffer sharing) with two thresholds for the proposed three levels. The result shows that the PBS with two thresholds can give more efficient control than the scheme with no priority, or the PBS with one threshold.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.6
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• pp.520-527
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• 2013

In this paper, a joint cell grouping and user association technique proposed for a semi-dynamic grouped network MIMO in a clustered heterogeneous cellular network (HCN). With the conventional macro BSs, small cells are being overlaid to increase a spectral efficiency per area and these small cells are expected to be concentrated to support exponentially increasing data traffic in hot spot areas. The main culprits of performance degradation in the clustered HCN are interference and load imbalance. The proposed scheme jointly handles them to maximize a proportional-fair metric. It is shown that the proposed technique can largely improve user average rate and proportional fairness among users than any other conventional schemes in the clustered HCN.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.123-137
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• 2004

The study on traffic assignment is actively being performed which reflect networks status using time. Its background is increasing social needs to use traffic assignment models in not only hardware area of road network plan but also software area of traffic management or control. In addition, multi-class traffic assignment model is receiving study in order to fill a gap between theory and practice of traffic assignment model. This model is made up of two, one of which is multi-driver class and the other multi-vehicle class. The latter is the more realistic because it can be combined with dynamic model. On this background, this study is to build multidynamic model combining the above-mentioned two areas. This has been a theoretic pillar of ITS in which dynamic user equilibrium assignment model is now made an issue, therefore more realistic dynamic model is expected to be built by combining it with multi-class model. In case of multi-vehicle, FIFO would be violated which is necessary to build the dynamic assignment model. This means that it is impossible to build multi-vehicle dynamic model with the existing dynamic assignment modelling method built under the conditions of FIFO. This study builds dynamic network model which could relieve the FIFO conditions. At the same time, simulation method, one of the existing network loading method, is modified to be applied to this study. Also, as a solution(algorithm) area, time dependent shortest path algorithm which has been modified from existing shortest path algorithm and the existing MSA modified algorithm are built. The convergence of the algorithm is examined which is built by calculating dynamic user equilibrium solution adopting the model and algorithm and grid network.

• Journal of Digital Contents Society
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• v.17 no.3
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• pp.111-118
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• 2016

Proxy mobile IPv6 (PMIPv6), which is a centralized mobility management protocol, are dependent on a local mobility anchor (LMA) to process all control and data traffics. Therefore, it has serious problems such as the tremendous traffic concentration into the core network and the triangle routing. In this paper, therefore, in order to alleviate these drawbacks, we propose a PMIPv6-based enhanced distributed mobility management scheme considering a user's traffic locality. Performance evaluation results indicate that in most cases, except for when a user's mobility rate is relatively very higher than the traffic rate, the proposed scheme shows better performance result than that of PMIPv6. Besides, it is demonstrated that the proposed scheme can be an effective alternative that can distribute the significant loads on the LMA of the core networks to the MAGs of the edge networks.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.77-90
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• 2002

Network expansion has been an inevitable method for most traffic equilibrium assignments to consider intersection movements such as intersection delays. The drawback of network expansion is that because it dramatically increases network sizes to emulate possible directional movements as corresponding links, not only is complexities for building network amplified, but computational performance is shrunk. This paper Proposes a new variational inequality formulation for a user-optimal traffic equilibrium assignment model to explicitly consider directional delays without building expanded network structures. In the formulation, directional delay functions are directly embedded into the objective function, thus any modification of networks is not required. By applying a vine-based shortest Path algorithm into the diagonalization algorithm to solve the problem, it is additionally demonstrated that various loop-related movements such as U-Turn, P-Turn, etc., which are frequently witnessed near urban intersections, can also be imitated by blocking some turning movements of intersections. The proposed formulation expects to augment computational performance through reduction of network-building complexities.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.43-54
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• 1997

In this paper, we introduce a secure and minimal protocol for authenticated key distribution over the CDMA mobile communication network. The CDMA mobile communication network has been developed the security protocol that provides a means for user authentication and subsequent protection of user traffic. However, this model has no security assumptions for the intermediate, fixed networks. To avoiding these drawbacks, we introduce a minimal authenticated key distribution protocol. This protocol provides the security of the intermediate and fixed network in mobile environment, and maintains the confidentiality of user identification and the minimum size of information flow compared with the existing protocols.

• Journal of Information Processing Systems
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• v.2 no.3 s.4
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• pp.159-162
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• 2006

Wireless LANs are becoming more widespread because of the rapid advance of wireless technologies and mobile computers. In this paper, we present the design and implementation of a system to help mobile users to select the most competent AP. By monitoring the network traffic of APs within the local LAN in real time, this system offers the mobile user the network utilizations, locations, and signal strengths of APs online. Based on the information, the user can select a competent AP with a high wireless bandwidth. Finally, we verified the accuracy of monitoring and calculating with regard to the utilizations of APs through real experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.431-434
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• 2012

The network traffic increases due to the web service and mobile application use while the smart device user increases rapidly. This paper presented the QRcode application as network data loss problem in the u-Health mobile environment and encryption module alternative. Therefore, the bio-information of the patient was collected and QRcode was produced in the PC based. In addition, the rate of reading recognized in the polution and damage was confirmed. The data traffic loss ratio using the network performance measurement equipment was tested.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.983-987
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• 2017

Multi-homing mobile router separates network for user connection and network for internet access using various interfaces for internet access. This paper proposes a load balancing metric in order that multi-network mobile router distributes its traffic to one of several heterogeneous network interfaces. To evaluate the performance of the load balancing metric, experiments on traffic balancing is performed on real commercial networks were used in Korea and Hong Kong.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.41-47
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• 2006

The construction of traffic facilities has generated a variety of problems in the equality and efficiency when it would be planed and evaluated. One of the reasons for these phenomena isn't the definition of an objective standard about benefit items. Thus, results of evaluation couldn't give a demonstration of confidence. But, the traffic facility construction and its operation costs are securely appeared. Therefor, it will be demonstrated to decide the benefit items in this study. Before deciding the items, user's satisfaction evaluation and economic analysis would be carried. We find out subway user's satisfaction higher than load traffic mode user in satisfaction evaluation, while subway's economic feasibility is lower than load facility, as a result of B/C analysis. In this inconsistent results, we found out that the benefit value is a little lower because of indefinite standard of it's items as comparing Busan Metropolitan City's population with subway's modal split ratio. Accordingly, we enumerate some benefit items in the case of feasibility evaluation as constructing traffic facility. And each of evaluation items' weight is estimated by using ANP. We found out that the weight value of accessibility has the highest one, that of punctuality has second, that of travel time has third, and benefit items according to improvement of user's traffic condition have much more important than those which were considered in the existence economic analysis.