• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.135-140
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• 2009

The wide deployment of wireless access technologies and the integration of various access network interfaces into a single terminal, allows mobile end-users to be always connected to the IP network, and to use those interface simultaneously. In this paper the CTE provides various access network interfaces capabilities, allowing reception of data over multiple service providers with different characteristics. Considerations for multiple network and service provider environments are regarded as essential for the successful deployment of convergence services in Next Generation Network (NGN). Event Driven Service (EDS) is regarded as a typical convergence service converging different functions of multiple service providers. This paper first describes the deployment model of NGN convergence services for multiple service provider environments. It also covers the service scenario of EDS, a convergence service for multiple service provider environments in NGN. Multiple provider environments stimulates the unified identifier management, namely ubiquitous identification (U-ID), to enable users to be provided convergence services without awareness of multiple provides. Then the designed structure and procedures of U-ID based EDS are given. Finally, the implementation results tested on Korea Advanced Research Network (KOREN) are described.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.25-41
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• 2002

The Korean National curriculum is divided into the curriculum, discretion, and extra curriculum activity. Extra curriculum among them consists of fie grounds, that is, a self-governing, adjusting, developing, service and exercise activity. The content of developing activity among them includes academic literary arts, in that the developing activity related to science. The developing activity connected with science can be a good chance which students can have deepened learning besides a regular course. In addition, effective management in science class can play an important role to cultivate scientific sense and to raise scientific talent. The study finds out how the management connected with science-related extra-curricula activity in science is actually going on. The study carries out a questionnaire with 40 teachers and interviews 5 teachers as well who are in charge of science-related extra-curricula activity connected with science. As a result, on the side of students, ① systematic introduction course in science is not given to them, ② the course is operating without considering students interests and levels, so it causes the problems of developing their potential ability and extension. On the side of teachers, ① they organize the science department based on school's situation and policy. ② they disregard teachers' roles and interests. ③ the science department's program is operating improvisedly rather than systematically, ④ the evaluation is done formally is found out. I have come to know that to manage a desirable science-related extra-curricula activity connected with science needs to have sufficient, detailed materials and experts from outside.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.109-112
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• 2020

Many devices are connected on the internet to give functionalities for interconnected services. In 2020', The number of devices connected to the internet will be reached 5.8 billion. Moreover, many connected service provider such as Google and Amazon, suggests edge computing and mesh networks to cope with this situation which the many devices completely connected on their networks. This paper introduces the current state of the introduction of the wireless mesh network and edge cloud in order to efficiently manage a large number of nodes in the exploding Internet of Things (IoT) network and introduces the existing Network Time Protocol (NTP). On the basis of this, we propose a relatively accurate time synchronization method, especially in heterogeneous mesh networks. Using this NTP, multiple time coordinators can be placed in a mesh network to find the delay error using the average delay time and the delay time of the time coordinator. Therefore, accurate time can be synchronized when implementing IoT, remote metering, and real-time media streaming using IoT mesh network.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.100-105
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• 2002

Now operating of many urban railway lines are currently in progress in tile Seoul, but the inadequate consideration of links between different lines could create inconvenience as the public transport. This paper is studied about the connection design of urban-railway service convinced for other metropolis railways forms and propose the base pilot plan of the railway network linking system in Seoul Metropolis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.303-306
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• 2008

In this paper, we propose a home-networking service using mobile phone and ZigBee module. Recently, ZigBee is widely used for various applications due to its characteristics. Especially, it is generally adopted for home network services. We propose a new home network service model using mobile phones. In the proposed architecture, the mobile phones are connected to conventional home network appliances using ZigBee dongle. Also, several servers are implemented for service management. We implement the whole components of the proposed architecture and show the validity of the proposed method. With the proposed service structure, it is expected to provide various ubiquitous services for the user.

• Journal of the Korea Society for Simulation
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• v.14 no.2
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• pp.83-92
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• 2005

Access networks connected in B3G networks provide its property network service. Hence, though mobile users may utilize only a network service from an access network, they can also use variety of network services from several access networks for their service satisfaction. To support heterogeneous changeable network service in access networks, the mobile terminal must implement heterogeneous system techniques so that it is able to change the network service by ISHO (Inter-System Handover) In this paper, we present the ISHO condition by the policy-based framework in B3G networks. Also, we propose an ISHO scheme to control network resources for the QoS management of a mobile session between UMTS and WLAN access networks. To support the QoS management, the proposed scheme is that it will be implemented before the resource exhaustion occurs to effect network performances.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.2
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• pp.55-63
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• 2019

Vehicle communication networks have some deficient network resources to support a vast multimedia service including safety driving information, video, news and some broadcast relayed from the playgrounds such as professional baseball games for autonomous vehicles. This paper deals with the framework for providing seamless multimedia service including safety driving information using multicast in cooperated-connected vehicle communication network (CVCN). It adopts smart-switch (SS) and smart intelligent multicast agent(SIMA) to support the seamless multimedia service. The SS manages and switches multimedia streams through SIMA in CVCN network. The SIMA to operate as an access point, is composed of multicast supporting part and control part of mobile devices/autonomous vehicles in CVCN network. Therefore this proposed technique using SS and SIMA within CVCN network is a new framework for multimedia service that can disperse the load of server.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.75-93
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• 2007

Recently, Service-Oriented Architecture(SOA) is on the rise to reduce the complexity of IT infrastructure, minimize cost for maintaining it and maximize the productivity and flexibility in business. SOA increases the adaptability by loosely coupling and it's main feature is that three elements such as service provider, service requester and service registry are connected with each other systematically. These make difficult to adopt traditional development methodologies to implement SOA. In this paper, we suggest a service-oriented development process with regard to the aspect of service provider and service requester. The process consists of six phases and each phase sets up with guidelines and artifacts. It can choose the process type along with the goal in Development Planning.

• Smart Media Journal
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• v.6 no.3
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• pp.89-94
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• 2017

The existing geofences provide only context-awareness service for entering or leaving the set region when a user sets a virtual region for his/her PoI(Point of Interest). Applying the mobile-geofence technology to the connected car technology, which is attracting attention as a next generation technology, it is possible to provide application service without additional infrastructure construction cost However, to do this, we need to expand and improve the functions of traditional geofence. In this paper, we propose and implement a flexible mobile-geofence in which the radii of each geofence applied to vehicles is changed according to context-aware in order to support connected cars technology based on the previously studied mobile three-dimensional geofence system. The proposed flexible mobile-geofence shows experimentally that the region of the geofence is changed according to context-aware of itself and its surroundings after applying a flexible decision algorithm by the flexible factor analysis. In the future, we are expected that the flexible mobile-geofence proposed in this paper will be applied not only to connected-cars technology but also to the application technology of V2X(Vehicle to Everything) for safe and efficient vehicle operation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.361-367
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• 2014

This paper is related to a new solar power conditioner for a built-in step-up chopper function. In the first step-up chopper proposed solar PV power conditioner for mutually connected in series with the input voltage of the bypass diodes are respectively connected to the positive terminal should install the mutual boosting chopper diode connected in series with the boost chopper switching element between the two power supply and at the same time the first and the second was connected to a second diode and a resonance inductor and a snubber capacitor in series with each other. And the common connection point between the bypass diode and the step-up chopper and the step-up chopper diode common connection point of the switching elements of the input voltage was set to the boost inductor for storing energy. In addition, between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point of the first auxiliary diode and the second common connection point of the auxiliary diode was provided, the resonance capacitor. Between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point and the common connection point of the resonance inductor snubber capacitor and connecting the third secondary diode, between two power supply lines is characterized by configuring the DC link capacitor bus lines in parallel. Therefore, it is possible to suppress the switching loss through, DC link bus lines, as well as there could seek miniaturization and weight reduction of the power conditioner itself by using a common capacitor of the non-polar non-polar electrolytic capacitor having a capacitor, the service life of the circuit can be extended and it is possible to greatly reduce the loss can be greatly improve the reliability of the product and the operation of the product itself.