• The Journal of Korean Association of Computer Education
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• v.10 no.5
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• pp.81-88
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• 2007

To support the movement of a mobile network consisting of several mobile nodes, the IETF NEMO working group proposed NEMO basic support protocol using bi-directional tunneling between the home agent and the mobile router. Since NEMO basic support protocol is based on bi-directional tunneling, all communications to and from mobile nodes are suffer from inefficient routing all the cases. To solve the routing inefficiency problem, several proposals are proposed. However, those proposals results in new problems, such as binding update storm and changes in existing protocol. Especially, binding update storm problem may cause the delay in binding update, this subsequently causes the difficulty for a real time service and the handoff delay on the movement of mobile network. In this paper, we propose a new binding update scheme which reduces binding update latency and the handoff delay through the distribution of the transmission time of binding update messages. The performance of the proposed scheme is also evaluated to demonstrate its efficiency. Simulation results show that the proposed scheme can efficiently reduce the binding update latency.

• Journal of KIISE:Information Networking
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• v.34 no.3
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• pp.218-225
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• 2007

As the research on home network technologies, sensor network technologies, and ubiquitous network technologies makes rapid progresses, wireless ad-hoc network have attracted a lot of attention. A wireless mobile ad-hoc network is a temporary network formed by a collection of wireless mobile nodes without the aid of any existing network infrastructure or centralized administration, and it is suitable for ubiquitous computing environments. In this paper, we suggest an extension scheme of a wireless mobile ad-hoc network based on limited multiple paths source routing protocol. This scheme reduces the overhead of route re-establishment and re-registration by maintaining link/node non-disjoint multiple paths between mobile hosts in a wireless mobile ad-hoc network or a mobile host in a wireless mobile ad-hoc network and a base station supporting fixed network services. By maintaining multiple paths, our scheme provides short end-to-end delay and is reliable extension scheme of a wireless mobile ad-hoc network to a fixed network. In this paper, our simulations show that our scheme outperforms existing schemes with regards to throughput and end-to-end delay. Also we show that our scheme outperforms multi-paths approach using disjoint routes with regards to routing overhead.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.3
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• pp.46-55
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• 2012

Recently, the concept of PES(Personal Environment Service) is being widely discussed on various standardization organizations such as ITU-R, ETSI, 3GPP, TTA and etc. The purpose of PES is to introduce the services which can dynamically, automatically and intelligently reconfigures the electronic, electrical, and mechanical equipment surrounding the user according to the user preferences included in a user's profile by using a smartphone embedding WPAN radio technologies such as bluetooth and WiFi. This research introduces an Android Platform-based PES system which consists of a PES app, PES devices and a PES server. A smartphone platform is Android 2.2(Froyo) version and 4 simulated PES devices were implemented by using Galaxy Tab. It has shown that the PES would be a killer application of M2M(Machine-to-Machine) or D2D(Device-to-Device) in the future and it would need to study how to update a user's profile based on analyzing user's behaviour for enhancing the PES user's satisfaction.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1509-1520
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• 2009

Contrary to ubiquitous environments, indoor computing environments like home network doesn't support user mobility. This paper suggests UPnP A/V multimedia system using prediction of mobility for adaption of seamless multimedia service. The multimedia system enables indoor mobile users to play multimedia contents by transferring the current session to an adjacent device automatically. The system represents users' contextual information by Five Ws and One H model, and predicts user's movements by using contextual information and transitions of locations. The prediction basically includes multiple locations so that it improves accuracy of prediction. We evaluated the suggested system using in accuracy of prediction, time for prediction, handover time for service, and the system showed that adapt ion of seamless multimedia service was enabled by using prediction of mobility on mobile user.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.144-152
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• 2007

The home network service which has been set up in the high price residential-commercial composition building of high price is supplied in the general apartment plentifully recently. But it has been supplied without accurate grasp under the aim of the most up-to-date IT industry and the convenient characteristic of life. In this research we research the present condition of network service in domestic and analyze the recognition degree of network service and the need using survey method. We find that the recognition degree is very high and a main considerable factor to purchase a house. However they prefer to be supplied as option rather than as lump. The consumers are ready to pay an addition expense for home network. It explain that they expect considerably home network service and home network system should be developed as considering the various individual characteristics.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.701-712
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• 2016

The number of subscriber of digital pay TV service such as Digital Cable TV and IPTV is increasing from various kind of service provider world widely. These services require personal information of users to provide VOD(Video on Demand) and customized contents. Therefore, massive amount of personal information collected by service provider can cause social confusion such as leakage of privacy and property damage. This paper investigates whether broadcasting stations are providing enough notification for privacy policy and methodology of collecting private information in proper way. Furthermore, we analyze actual network traffic of IPTV service between user and service provider to suggest solution of privacy protection along with current status analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.11-19
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• 2007

A ubiquitous network environment is a system where the user can avail of the network's services anytime, anywhere. To establish such an environment, studies continue being conducted on wireless communication technology and mobile terminals. The company that provides such services should have an established system for authentication, authorization and charging for users. This service is referred to as Authentication, Authorization, Accounting(AAA), and its aspects have been consistently studied. On the other hand, existing studies have been promoted with regard to the authentication and efficiency of the mobile terminal. One of the method is that the mobile terminal contacts to the home authentication server through the external authentication server every time it is required and; another one is to use a medium server to provide authentication in the middle between them. Thus, this study aims to determine the best method to use ticketing, where tickets are provided through a mobile terminal, complete with authentication and authorization features. Also, as it uses ticket, it can efficiently provide mobile verification processing.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.298-306
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• 2016

With the advent of Internet of Things (IoT) technology that allows the communications between things and devices over the Internet, a lot of researches on the IoT services, such as smart home or healthcare, have been progressed. In the existing machine-to-machine (M2M) communications, however, since the underlying link-layer technologies, such as Bluetooth or ZigBee, do not use the Internet Protocol (IP) communication, those technologies are not suitable to provide the IoT services. Accordingly, this paper discusses how to provide the Internet services in the M2M communication, and propose an implementation of the Constrained Application Protocol (CoAP) over 6LoWPAN for providing IoT services in the BLE networks. Based on the implementation, we compared the performance between HTTP and CoAP for IoT communications. From the experimental results, we can see that the CoAP protocol gives better performance than the HTTP protocol with two times higher throughput, 21% faster transmission time, and 22% smaller amount of generated packets.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.203-210
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• 2011

The current sensor network analyzes the data collected by the sensing of fixed sensor nodes and provides a service. However, this method cannot actively handle the state and the change in the position of people, 'the target for sensing and the change in the environment', including home automation, building automation and real-time road & weather information, and healthcare environment, etc. To support a dynamic situation which is appropriate for an individual in this diverse environment, it is necessary to provide actively differentiated specific information according to the movement of people and the changes in the environment. In this study, a individualized sensor mobile agent middleware which provides the individualized information (the location of fire incidence and the trace for the path of spread), has been realized through the sensor network environment constructed by the installation of wireless sensor nodes mounted with mobile agent middlewares in buildings.

• The KIPS Transactions:PartD
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• v.13D no.5 s.108
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• pp.741-748
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• 2006

This paper describes the system which provides home entertainment services to users using the middleware-cooperation module which makes UPnP and ACAP cooperate with each other. UPnP or ACAP providespowerful functionalities to its own network to play multimedia contents using its own resources. U one middleware uses the information and the resources of another middleware, itcould provide services with more contents and more powerful functionalities than those which it originally provides. This paper develops the middleware-cooperation module to make two middleware cooperate with each other and use resources of another middleware. The middleware-cooperation module makes UPnP and ACAP cooperate with each other, and it makes them share their information and resources without resource collision.