• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.584-590
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• 2016

This paper proposed "Priority Scheduling and MultiPath Routing Protocol (RRPS) for preventing communication disruption in the urban environment" to minimize the disconnection or disruption of V2I and V2V communication in the urban environment where communication is frequently disconnected according to density. The flow of the RRPS is explained as follows. RSU Request Priority Scheduling (RRPS) is used to apply the priority of the request message prior to reaching the end line by using the Start Line and End Line, which are the management areas of the RSU). This paper also proposed MPRP (Multi Path Routing Protocol) design to set up the multipath to the destination. As a result, the proposed RRPS improves the processing efficiency of V2I by applying priority scheduling to the message of the vehicle requesting the information in the RSU, and can prevent the communication disconnection. Thereby, it is improved the transmission success probability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2665-2670
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• 2015

VANET is ad-hoc network in which vehicles are treated as node and these nodes are communicating with each other as well as RSUs on the road. In VANET, scheduling is a very important issue as the request data are to be delivered to the recipient vehicle properly and accurately. It is also critical that any request data which is sent to the vehicle is received by it in the time period for which the vehicle will be in range of RSU. RSU picks the one with the highest priority to serve based on the scheduling scheme. In this paper, we propose a scheduling algorithm to select the one with the highest priority in RSU, in which an RSU can transfer the overload requests to other RSUs. We use the modified DBP scheme to calculate the priority of request data. Simulation results show that our scheme outperforms other scheduling schemes under various conditions.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.352-358
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• 2003

A cluster of servers is the most promising solution to provide highly scalable and highly available network services with low implementation cost. One of popular solutions is using dispatcher as a request distributor. However this solution has the problem that is can be the bottleneck or single-point of failure point of itself. ONE-IP, the previous work, solves this serious problem by using broadcast message for distributing the request packet in LAN. Using simple scheduling technique, in addition, the overhead due to dispatching the request becomes minimal. However, as ONE-IP using very simple static scheduling algorithm, it would spread the request among servers unevenly and downgrades the cluster performance consequently. In this paper, we propose an improved TCP connection scheduling technique solving this unbalanced distributing problem. Using Round-Robin(RR) scheduling instead of hashing clients IP address, proposed technique can more evenly distribute incoming service requests among the servers. Experiments show average 3.8% improved performance in throughput compared to original ONE-IP technique.

• Journal of Internet Computing and Services
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• v.1 no.2
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• pp.61-67
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• 2000

In case of the remote controllable web-camera that was took notice especially in internet real-time broadcasting systems, a great many clients connect the server of web-camera to request the service. So, the scheduling methods are important. Web-camera systems have used to the traditional FIFO(First In First Out) or SDF(Shortest Distance First) scheduling method. But they does not satisfy both the minimization of moving distance on the web-camera and the fairness on the users. In this paper, We propose the 2D scheduling method, As a result, the moving distance of the web-camera decreases compared with FIFO scheduling method. And the starvation state on the user's request does not happen compared with SDF scheduling method. Thus, if the remote controllable web-camera systems use the 2D scheduling method, they are satisfied with the minimization of moving distance on the remote controllable web-camera and the fairness on the users simultaneously. Therefore the user's satisfaction and the performance of the systems are improved.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.57-60
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• 2003

IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple service. Among the service classes supported by the wireless MAN, the BE class is ranked on the lowest position in priority and is usually deployed by multicast and broadcast polling MAC scheme. In provisioning such BE service, the delay performance is influenced by a number of components including restrictions on resource request per SS, the number of request opportunities in upward frame, scheduling requests at BS, and contention resolution method. As candidate components of MAC function for BE service, we propose single and multiple request schemes (for controling the number of requests per SS), exhaustive and limited request schemes (for regulating the amount of grant per request) and FCFS, H-SMF, pure SMF, SS-wise Round Robin, and pure Round Robin (for scheduling requests at BS). Then, we construct MAC schemes by combining the above components and evaluate the delay performance exhibited by each MAC scheme using a simulation method. From numerical results, we investigate the effect of MAC components on average delay and delay variation and observe the dissonance on collision reduction in a resource - limited environment.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.1
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• pp.22-32
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• 2003

Many of multimedia applications in distributed environments generate the packets which have the real-time characteristics for continuous audio/video data and transmit them according to the teal-time task scheduling theories. In this paper, we model the traffic for continuous media in the distributed multimedia applications based on the high-bandwidth networks and introduce the PDMA algorithm which is the hard real-time task scheduling theory for guaranteeing QoS requested by the clients. Furthermore, we propose the admission control to control the new request not to interfere the current services for maintaining the high quality of services of the applications. Since the proposed admission control is sufficient for the PDMA algorithm, the PDMA algorithm is always able to find the feasible schedule for the set of messages which satisfies it. Therefore, if the set of messages including the new request to generate the new traffic. Otherwise, it rejects the new request. In final, we present the simulation results for showing that the scheduling with the proposed admission control is of practical use.

• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.87-93
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• 2007

In the component based software development, it is very important to interface between modules of component. Almost of existing method, Connectors are deal with all communication channels between two or more components/interfaces by RPC(Remote procedure call) and event call. But these process has limits when component send a lot of request call to other component through connector. That is, we need more efficient interface method that connector can process multi request call. In this paper, I propose interaction scheduling algorithm using message queue in the connector. For this purpose, I use message buffer which operate to save and load message temporarily.

• The Journal of Engineering Research
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• v.7 no.1
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• pp.29-36
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• 2005

In multi-server environment, We have to design a mechanism that selects appropriate servers for processing each service request while maximizing server throughput and minimizing average response of service requests. In this paper, we propose a job scheduling method for courseware delivery system using a idle computing resources on LAN. The proposed scheduling method propose an approach that uses client service request time, server available period and server load of requested service as guidelines of server selection. Comparing the our approach method to conventional one, experiments that the proposed approach provides better performance.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.179-192
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• 2009

In wireless environments, it is very effective to introduce a data broadcast system for providing a number of clients with mobile data services. In particular, an efficient broadcast scheduling and a caching strategy are very important for performance of data broadcast systems in wireless environments which have such inherent restrictions as low bandwidth, frequent disconnections, and short battery life. In this paper, we present a data broadcast scheduling strategy using bit vectors to cope with dynamic request patterns of clients. In addition, we also propose an efficient caching strategy, 2FWT, that takes characteristics of the broadcast scheduling strategy into account. Finally, we evaluate performance of the data broadcast system. According to the results, the proposed system generally shows better performance than others.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.69-78
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• 2006

The client request scheduling techniques for web server can classified into the scheduling techniques considering a document size to be requested and not. The scheduling techniques considering a document site to be requested provides a better average response time than another As the size-based SRPT(Shortest Remaining Processing Time first) is typical, and the most of scheduling techniques considering a web document size are based on SRPT. Most of existing researches, however, have not considered the feature of HTTP/1.1 which enable the clients to request concurrent multiple inlined-contents in a HTML document via each connection. In this paper we propose a connection scheduling technique with the scheduling window which provides a better response time in HTTP/1.1. The experimental results show that the performance with the proposed approach is improved about $10\%$ more than the connection scheduling with SRPT.