• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.11-14
• /
• 2005

In this paper, we propose a method for transmitting SMS(Short Message Service) for VoIP(Voice over IP) service supporting multi-protocol. The multi-protocol VoIP under consideration are generally composed of H.323, SIP and MGCP and Most ITSPs(Internet Telephony Service Provider) provide VoIP service with H.323 and SIP now. SMS is killer application in mobile telecom service and many people of various field use that service. For example, user can send many SMS messages and substitute e-mail. Also SMS can be provided with various internet application. Ahn, legacy phone of KT, can use SMS. Therefore VoIP phone also can be required with the same requirement. With the multi-protocol VoIP we will propose several methods sending efficiently SMS. To show the validity of the proposed method some examples are given in which the results can be expected by intuitive observation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.4
• /
• pp.784-799
• /
• 2013

This paper presents an adaptive rate control scheme for streaming-based content sharing service. This scheme delivers multimedia contents from a user device to another device or seamlessly redirects streaming service across heterogeneous user devices. In the proposed scheme, a streaming server adjusts video quality level according to the network and client status. Our scheme is different from other rate control schemes, because the video quality at the server is decided not only based on the available bandwidth, but also based on the device characteristics and bandwidth requirement at the access network. We also propose a bandwidth estimation method to achieve more equitable bandwidth allocations among streaming flows competing for the same narrow link with different Round Trip Times (RTTs). Through the simulation, we prove that our scheme improves the network stability and the quality of streaming service by appropriately adjusting the quality of the video stream. The simulation results also demonstrate the ability of the proposed scheme in ensuring RTT-fairness while remaining throughput efficient.

• The Journal of Information Technology
• /
• v.9 no.3
• /
• pp.33-47
• /
• 2006

We will can do quality of measurement of service that thing is quite abstract concept. Generally, we speak Service of quality that property of a product, usability of use, social quality requirement to a quality of service by wide meaning. A purpose of this study was comparison regarding a way to measure of service quality, and in the insufficient section there was anything, and progress of model study of service left no matter how much focus to it. There is comparative study a few progress of literature of a PZB, SERVQUAL, SERVPERF, model. Desarbo, Huff, Rolandelli, & Choi, (1994: 125-131) proposed that to solve the above model contradiction point, and Presentation called a plan based on to Conjoint analysis. There is Critical point to decide on priority order of proposed model of service measurement. This study has a lot of the pieces which are short by absence of empirical study, but will make a supplementation in next term study.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.2 no.3
• /
• pp.24-35
• /
• 2003

With the arrival of 3rd generation cellular networks it is expected that a lot of new cellular services will be available to the mobile users like video calling, location based services etc. Similarly MBMS is one such service which is targeted for 3G mobile users for viewing talk shows, live sport events etc. One shall view this service like a small portable T.V being carried by the mobile user. The user watches the programs of his liking by joining if he wishes. In this paper we focus on the possible UTRAN architectures to provide MBMS service within UMIS networks. The paper primarily focuses on the requirement aspect, notification aspect and the mobility aspect. The paper lists many options for notifications and elaborates on them in terms of pros and cons. In the end the paper conclude with an UTRAN architecture for MBMS service which meets the requirements of this service as well as makes minimum changes to the existing UTRAN architecture while attempting to save terminal power for this service.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.7
• /
• pp.1161-1168
• /
• 2016

Battery energy storage system(BESS) attract the attention of the power system operators with its fast response to a disturbance in spite of its limited energy capacity. This paper proposes the operating method of BESS for following the Automatic Generation Control(AGC) frequency control which is centrally distributed by a system operator. As BESS needs to just meet the control requirement from the system operator, it should be able to properly manage the state of charge(SOC) of BESS to be available to control signal. For doing these, the proposed method distributes the control requirement to available batteries in proportion to its SOC. In addition, unavailable batteries are controlled to recover the SOC to an appropriate range, and the recovering power is supplied by available batteries meeting the control requirement. Moreover, the proposed method manages the efficiency of power conversion system (PCS) by limiting the number of PCS to be assigned for the low control requirement. Finally, the case studies are carried out to verify the effectiveness of proposed strategy.

• Journal of KIISE:Computer Systems and Theory
• /
• v.28 no.5
• /
• pp.213-217
• /
• 2001

Excessive memory buffer requirement in continuous media playback is a serious impediment of wide spread usage of on-line multimedia service. Skewed access frequency of available video files provides an opportunity of re-using the date blocks which has been loaded by one session for later usage. We present novel algorithm which minimizes the buffer requirement in multiple sessions of multimedia playbacks. In continuous media playback originated from the disk, a certain amount of memory buffer is required to synchronize asynchronous disk. Read operation and synchronous playback operation. As aggregate playback bandwodth increases, larger amount of buffer needs to be allocated for this synchronization purpose. The focus of this work is to study the asymptotic behavior of the synchronization buffer requirement and to develop an algorithm coping with this excessive buffer requirement under bandwidth congestioon. We argue that in a large scale continuous media server, it may not be necessary to read the blocks for each session directly from the disk. The beauty of our work lies in the fact that it dynamically adapts to disk utilization of the server and finds the optimal way of servicinh the individual sessions while minimizing the overall buffer space requirement. Optimality of the proposed algorithm is shown by proof. The effectiveness and performance of the proposed scheme is examined via simulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.2
• /
• pp.268-279
• /
• 1997

In this paper, we show the movable boundary (MB) method is the effective bandwidth allocation strategy for the ABR service among existing bandwidth allocation methods. The MB method can gurantee the QOS requirement according to the service priority and improve bandwidth utilization using the characteristics of the ABR service. The threshold values of the MB, which have an important effect upon connection blocking probability(CBP) performance of each service, are obtained by simulation. The MB method with the fixed thresholds, however, may not have good performance to variation of input traffic parameters. We suggest the dynamic MB method which changes the threshold values adaptively according to the required bandwidth of input traffic. We also show that the dynamic MB method can urantee the CBP performance according to the service priority regardless of variation of input traffic parameters.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.494-500
• /
• 2004

The purpose of this thesis is to know and understand the user requirements to provide with intelligent railway information service in response to the Ubiquitous environment. The railroad specially has a disadvantage of door-to-door service, however by using the information and communication techniques, we can provide the passengers who are using the intermodal transportation means with the realtime information, therefore we can overcome the above disadvantage. To deduce the passenger's needs for providing the future-type railway information service, we introduce the results of the questionnaire. In chapter 2, we studies on the concepts of intelligent railway information service, and in chapter 3, we investigate the cases of Japan and China, and in chapter 4, we study the passager's satisfaction by the questionnaire concerning the railway information service and suggest the needs for information offering.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1453-1462
• /
• 2009

It is very important for performance of information system that we make an effort to raise user's satisfaction by continuously grasping user's requirement by evaluation of PMIS based on ASP service quality and reflecting this to information system. However, It is lack that developments of suitable evaluation index of PMIS based on ASP service quality. Hereupon, In this study, we propose the evaluation indicators. First, The evaluation area is classified by form the foundation of D & M IS Success Model (2003); system quality, information quality, service quality. Second, The detail evaluation item which include considerations which are gotten through investigation of the construction industry and PMIS based on ASP is grouping by form the foundation SERVQUAL which is a service quality evaluation tool proposed PZB(1988). It is suitable to evaluate PMIS based on ASP service quality in construction industry and able to evaluate various aspects.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.6B
• /
• pp.997-1003
• /
• 1999

It is required that synchronization model can describe various multimedia objects flexibly in the view point of time relationship and also respond quality of service requirement about jitter which is time difference between intramedia and skew which is time difference between intermedia. es desirable quality of service requirement. Proposed model applies maximum jitter and skew values which can be allowed, and then it presents high quality of service and real applies maximum jitter and skew values which can be allowed, and then it presents high quality of service and real time characteristics. In this paper we expend Petri-net and propose new synchronization specification model and apply two analysis method of Petri-net to prove oIn this paper we suggest multimedia synchronization model that is based on the Petri-net and servicur model suggested. We compared with other models and showed high QoS.