• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.355-364
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• 2010

A session transfer method, referred to as a Recipient Serving-call session control function (S-CSCF) Assured (RSA), is proposed in order to support both session mobility and consistency in IP multimedia subsystem (IMS) based next generation network (NGN). RSA session transfer simplifies a basic session transfer operation specified in [1] by using the user agent client (UAC) like characteristics of an S-CSCF. To show its efficiency, the session transfer delay and the traffic cost of RSA session transfer are investigated and compared with those of existing session transfer applications, including Assured and Consultative session transfers, by practically considering multiple session transfer failures. It is shown that RSA session transfer can further improve user experience by reducing session transfer delay as well as traffic cost than Assured and Consultative session transfers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.15-23
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• 2013

In this paper, we propose a session management and control architecture for N-Screen services, which enable users to change devices and transfer contents among user's devices during service by session transfer and split. In N-Screen services, users may have multiple devices with different attribute such as screen resolution, CPU capability and access network interfaces. Also, since users may change devices during service, or one user may use multiple stream, N-Screen services need to enable the user to share and transfer contents across N-Screen devices. We introduce the management and control servers to provide session split over user multiple devices and session continuity while changing device. Furthermore, the proposed architecture provides the device capabilities aware session continuity. In addition, the proposed scheme minimizes the session transfer delay and content server processing load. We present results that show the effectiveness and usefulness of proposed architecture.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.63-72
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• 2003

This study investigated how cognitive style and training context influenced visual discrimination skill acquisition and transfer under time pressure. This experiment consisted of a screening session, a training session, and a transfer session using random polygon comparison tasks. Screening session was designed to separate participants according to their cognitive style (analytic or holistic). Training session was divided into difficult and easy conditions. In transfer session, participants compared polygon pairs in a novel task. The stimuli were presented for 1.5 seconds to examine the influence of time pressure. Through the all sessions, this experiment measured accuracy and response time. According to the results of this study, analytic group responded as quickly as holistic group in the beginning of training session because time pressure induced them to the holistic strategy. However, as training session progressed, their slopes of reaction time increased, suggesting that their own analytic style emerged. Holistic group showed flatter slopes than did analytic group for training session. Of interest is the slopes increased at the beginning of transfer session, suggesting that they developed analytic strategies in difficult training context. It is suggested individuals differently develop strategic processing skills depending on cognitive styles even under time pressure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.555-560
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• 2014

Recently, there are many researches on sharing group session key for members in a group. Among them, Harn and Lin proposed a scheme based on the Shamir's group session key and Liu, Cheng, Cao, and Jiang improved it to reduce the specific weakness. Especially, these schemes are based on the finite integer ring to protest the insider attack, in which a valid member can derived another member's secret using known information. In this paper, it is shown that the finite integer ring implies the failure of the reconstruction of group session key depending on the adopted parameters. We fix this problem and propose new group session key transfer scheme using the Shamir's secret sharing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1148-1159
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• 2012

It is of great significance in the NGN - which supports a ubiquitous network environment in which users can use multiple devices and all the devices are connected to networks - to support the terminal mobility as well as service continuity. The IMS architecture, which is considered as session control layer in the NGN, exists to support a wide range of advanced new services in addition to the traditional voice and data connectivity offerings of "old" telecommunications. The recent IMS specification also defines IUT (Inter UE Session Transfer) functionality in order to support service continuity in the NGN. However, service continuity in IMS has a limitation that two terminals involved in session transfer should belong to the same user. In this paper, we proposed a new device discovery mechanism for IMS and extended UEs with a few capabilities to overcome some of IMS's limitations. We also analysed how much overhead of the proposed method in terms of signaling cost will be.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.21-32
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• 2012

We develop architecture of a virtual aggregation gateway (VAG) which enables composite application streaming based on N-Screen-as-a-Service (NaaS) using cloud computing in thin-client environment. We also discuss the problem of server computing burden in large scale multi-client case for screens sharing with composite application streaming over the internet. In particular, we propose an efficient Framework of N-Screen Session Manager which manages all media signaling that are necessary to deliver demanded contents. Furthermore, it will provides user with playback multimedia contents method (TV Drama, Ads, and Dialog etc) which is not considered in other research papers. The objectives of proposing N-Screen Session Manager are to (1) manage session status of all communication sessions (2) manage handling of received request and replies (3) allow users to playback multimedia contents anytime with variety of devices for screen sharing and (4) allow users to transfer an ongoing communication session from one device to another. Furthermore, we discuss the major security issues that occur in Session Initiation Protocol as well as minimizing delay resulted from session initiations (playback or transfer session).

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1439-1446
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• 2017

Steady exercise or walking exercise is helpful for the treatment of chronic diseases or cancers. In this paper, I presented a smart poster to enable the patients to exercise while moving between the smart posters, dynamically, in order to provide better exercise effect to them. It can be a new form of exercise prescription that combines exercise with walking using smart posters. The personalized exercise prescription is downloaded from the management server in real time when the patient approaches, and induces the patient's exercise and walking. In addition, the smart poster helps patient to move to other posters in order to induce more walking exercise. To achieve this, I proposed a transfer protocol that autonomously exchanges session information between smart posters in this paper. Moreover, the smart poster based on Raspberry was implemented to verify validity of this protocol, and an experiment was conducted to measure the request and response time between smart posters in the implemented environment. In the experiment, when the other poster sent the message requesting the exercise session 100 times and received the response message, the 95 percentage of received messages had the response time within 0.05 seconds.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.103-114
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• 2008

Single Sign-On is an authentication scheme that enables a user to authenticate once and then to access to the resources of multiple software systems without re-authentication. As web services are being integrated into a single groupware, more web sites are adopting for user convenience. However, these Single Sign-On services are very dependent upon the cookies and thus, simple eavesdropping enables attackers to hiject the user's session. Even worse, the attacker who hijacked one session can move to another site through the Single Sign-On. In this paper, we show the vulnerabilities of the top ranked sites regarding this point of view and also propose a way to protect a user's session.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1112-1122
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• 2008

This paper reviews the Parlay X and proposes SIP multimedia session control mechanism which is able to be implemented over IMS using Extended Call Control APIs of Parlay X. Parlay X is one of the industrial standards of Open API in the telecommunication to open network resources and capabilities to third party service providers. In this paper, SIP session control mechanism is described by depicting call flows of basic and essential session handling methods including session initiation, transfer, restoration, and termination. We also show how easy Parlay X Extended Call Control APIs can be used for the purpose of complicated calls handling in the IT applications. To verify feasibility of the blended services based on convergence of telecommunication and internet with regard to performance, we accomplish experimental performance of Extended Call Control APIs from IT application through open service gateway. We show Open API could be applied to next generation network based on IMS without serious degradation of the network performance.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.729-732
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• 1998

ITU-T recommends T.120 for multimedia conferencing data protocols. In this paper, generic model of application protocols is shown for guaranteeting internetworking between application protocols in application users. And using generic conference control and multipoint communication service, multipoint binary file transfer application protocol is shown throughout application protocol generic model on public session environment.