• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2056-2063
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• 2015

Recently, as the service scale of cloud service is expanded, an anxiety due to concerns on new vulnerabilities and security related incidents and accidents are also increasing. This paper proposes a certification scheme for multiple session management of security sessions which are generated after the user authentication. The proposed session multiplexing scheme enables the independent management of security sessions in the level of virtualization (hypervisor) within the service provider. As a result of performance analysis, providing a strong safety due to session multiplexing and mutual authentication, and the superiority of performance was proven by comparing it with the existing mutual authentication encryption algorithms.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.578-587
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• 2012

One of the key elements in the emerging, packet-based long term evolution (LTE) cellular systems is the deployment of multiple femtocells for the improvement of coverage and data rate. However, arbitrary overlaps in the coverage of these femtocells make the handover operation more complex and challenging. As the existing handover strategy of LTE systems considers only carrier to interference plus noise ratio (CINR), it often suffers from resource constraints in the target femtocell, thereby leading to handover failure. In this paper, we propose a new efficient, multi-objective handover solution for LTE cellular systems. The proposed solution considers multiple parameters like signal strength and available bandwidth in the selection of the optimal target cell. This results in a significant increase in the handover success rate, thereby reducing the blocking of handover and new sessions. The overall handover process is modeled and analyzed by a three-dimensional Markov chain. The analytical results for the major performance metrics closely resemble the simulation results. The simulation results show that the proposed multi-objective handover offers considerable improvement in the session blocking rates, session queuing delay, handover latency, and goodput during handover.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.6
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• pp.770-778
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• 2012

In this paper, we propose a multi-path construction scheme to improve the survivability of a multicast session in military hybrid networks. A military hybrid network consists of a static backbone network and multiple mobile stub networks where some nodes are frequently susceptible to be disconnected due to link failure and node mobility. To improve the survivability of multicast sessions, we propose a construction scheme of ${\kappa}$ redundant multi-paths to each receiver. In order to take account of different characteristics of static and mobile networks, we propose quite different multi-path setup approaches for the backbone and stub networks, respectively, and combine them at the boundary point called gateway. We prove that our proposed scheme ensures that each receiver of a multicast session has ${\kappa}$ redundant paths to the common source. Through simulations, we evaluate the performance of the proposed schemes from three aspects : network survivability, recovery cost, and end-to-end delay.

• The KIPS Transactions:PartC
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• v.15C no.2
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• pp.87-92
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• 2008

This paper proposes a session control model for the P2P(Peer to Peer) IPTV(Internet Protocol Television) services and presents the IPTV session control procedures based on the proposed model. Since, while public IPTV traffic is usually processed via a separate network, P2P IPTV traffic is processed together with the conventional Internet access traffic, the P2P IPTV control mechanism needs to provide multi-stream processing for the constituent TPS(Triple Play Service) traffic and corresponding QoS(Quality of Service) control functions. Besides, P2P IPTV session control mechanism should provide appropriate multicast control functions in order to support effective transmission of video traffic generated by personal IPTV broadcasters. The P2P IPTV session control model proposed in this paper is designed to be based on the standard SIP(Session Initiation Protocol), IGMP(Internet Group Management Protocol), and COPS(Common Open Policy Service) protocol so that it can contribute to the easy and prompt deployment of inter-operable P2P IPTV platform.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.430-438
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• 2001

In this paper, we present the design and implementation of a web-based distance learning system supporting the collaborative browsing. Our system consists of an education affair management system, a video conferencing server/client, a white-board server/client, a session manager and a web browser sharing system. Among other things, our collaborative web browser is unique and not found in any other system. The web browser shows synchronously the same web pages as the lecturer moves through them. Therefore, it allows the student to feel real-time surfing gust as the lecturer would. The session manager supports multi-user and multi-group, and integrates various synchronous collaborative component into one distance learning system by providing the same session data and information of users in a session group. Our collaborative browsing system can increase the efficiency of distance learning and provides the effect of learning in the same classroom by supporting various synchronous functionalities, such as collaborative browsing.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.17-24
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• 2008

At the view of Application layer, there are many researches to achieve the cross-layer optimization with Physical layer. Scalable video coding is good example. Although it is necessary to consider the session layer which lies halfway between two layers, the research about that is insufficient. We present a feasible solution of dynamic session control for scalable video coding over IMS.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.273-278
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• 2013

Recently, user authentication schemes using smart cards for multi-server environment have been proposed for practical applications. In 2009, Liao-Wang proposed a secure dynamic ID based remote user authentication scheme for multi-server environment that can withstand the various possible attacks and provide user anonymity. In this paper, we analyze the security of Liao-Wang's scheme, and we show that Liao-Wang's scheme is still insecure against the forgery attack, the password guessing attack, the session key attack, and the insider attack. In addition, Liao-Wang's scheme does not provide user anonymity between the user and the server.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.511-523
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• 2007

In broadband convergence network(BcN), heterogeneous broadband wired & wireless subnetworks and various terminal equipments will be interconnected. In order to provide end-to-end realtime multimedia services on such heterogeneous networking environment, as a result, two major problems should be resolved: i) Multimedia session establishment & negotiation that adjusts the differences in the capability of multimedia data processing at the end terminal nodes, ii) quality of service(QoS)-guaranteed connection establishment or resource reservation with connection admission control(CAC) in each heterogeneous subnetworks along the path. The session layer signaling(e.g., SIP/SDP) should be extended for QoS negotiation, and must be tightly cooperating with network layer signaling or resource reservation with CAC function. In this paper we propose a session and connection management architecture for the QoS-guaranteed realtime multimedia service provisioning on BcN, with Q-SIP/SDP, resource reservation protocol with traffic engineering extension, and CAC functions. The detailed interaction scenario and related algorithms for QoS-guaranteed realtime multimedia session, resource reservation and connection establishment are explained and analyzed. From the experimental implementation of the proposed scheme on a small scale BcN testbed, we verified that the proposed architecture is applicable for the realtime multimedia service provisioning. We analyze the network performance and QoS parameters in detail.

• Journal of Korean Home Economics Education Association
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• v.33 no.1
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• pp.151-167
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• 2021

This study reports on the development of a dietary education program for Korean young adults in single-person households. The 7th National Health and Nutrition Survey (2016-2018) was used to compare and analyze the dietary behavior of single-person households and multi-person households, and an online survey was conducted on 350 young adults (age 19-39 years) living in Seoul. According to the analysis, single-person households had higher rates of breakfast and eating out than multi-person households, and significantly lower average intake of energy and nutrients (p<0.05). In particular, in the case of single-person households, the lower the frequency of cooking at home, the higher the rate of breakfast and the higher the frequency of eating out and delivery food (p<0.05). Based on the survey, a dietary education program for young adults single-person households was developed by applying the DESIGN six-step procedure and social cognitive theory as a conceptual model. The first session consisted of the health and economic benefits of home-cooked meals, the second session of the importance of the breakfast and the effect of exercise in life, the third session of the importance of balanced nutrition and the principles of a healthy diet, the fourth session of food safety and storage, and the fifth session of social dining. Each session was composed of a combination of theoretical lectures to motivate 'more making and eating healthy home-cooked meals' and cooking practice for improving behavioral performance.