• Journal of Digital Convergence
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• v.12 no.8
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• pp.309-319
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• 2014

Virtual Network service is a key characteristics of future Internet which is debate internationally. There are two kinds of network virtualization technologies considered lately: network functions virtualization and virtual network approaches. Several national wide research networks including US's GENI project have experimented technologies for future Internet and in particular network virtualization is one of key issues. Representative Korean research network, KREONET, is working on deploying virtual network framework as a preliminary for future Ineternet using the virtualization model of SDN/OpenFlow which is typical network model of future Internet. This paper proposes a stepwise model to bring virtual network services in KREONET. Firstly, we requirements of KREONET users' virtual network service and network resource management and network deploying virtual network. Finally, we verify the adequacy of our virtual network model for KREONET.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.108-117
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• 2007

RConsumer Portal is defined as "a combination of hardware and software that enables two-way communication between energy service providers(ESP, like KEPCO) and equipment within the consumer's premises". The portal provides both a physical link(between wires, radio waves, and other media) and a logical link(translating among language-like codes and etiquette-like protocols) between in-building and wide-area access networks. Thus, the consumer portal is an important, open public shared infrastructure in the future vision of energy services. This paper presents an XML based standard specification of service-oriented, open protocol for consumer portal system architecture. In the framework level, the XML protocol provides a useful bridge between services and platforms. The proposed standard protocol has been implemented into our developing consumer portal pilot system. The results imply the potential of global standards for consumer portal system by its minimum overhead in network and processor. The reposed XML is designated psXML in this paper.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.345-350
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• 2014

According to the necessity of smart working with various mobile devices, and the increasing services based on the converged infrastructures such as Cloud, Wearable Computing, Next Generation Wired/Wireless Mobile Networks, the network reliability has been one of the most important things. However, the research related to the network reliability is still insufficient. To solve these problems, we propose the ISNTC (Intelligent Safe Network Technology based on Cloud), which uses the safe network technique based on SDN, to be adopted to the smart working environments. The proposed ISNTC guarantees secure data forwarding through the synchronized transmission path and timing. We have verified the throughput which outperformed the existing techniques through the computer simulations using OPnet.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1527-1537
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• 2006

The server system of digital contents has to how the context information about client devices to provide the appropriate contents for each device effectively. CC/PP standard specification is an agreement for describing and transmission of the information related with a client device. In this case, the information on device hardware and software, networks and user's preference is included here. In the mean time, WAP forum defined W-HTTP protocol to transmit the CC/PP profile information of a client device to a server system. However, the client devices which use existing HTTP protocol to transmit their information cannot provide the CC/PP profile information to a server. In this paper, we propose an effective method to create and provide the CC/PP profile in the clients which use not only HTTP protocol but also W-HTTP protocol to transmit device information.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.407-412
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• 2002

A FR-ATM interworking function that has FR and ATM interfaces, should guarantee the QoS of both frame relay and ATM networks. The IWF requires the policing mechanisms for FR and ATM respectively, and needs to map the traffic parameters each other. In this case, traffic parameter mapping and policing function are performed independently. In the aspect of FR traffic policing, this function degrades processor performance if it is worked by software, or includes additional hardware function. The best way to solve this is to integrate this function into ATM function because ATM is performed by well defined hardware already. In this paper we propose the integrated traffic control mechanism. That is, frames are segmented to cells first, and then policing mechanism is applied to the cells to guarantee the FR QoS. Therefore proper policing algorithm is essential to the integrated FR traffic mechanism. The evaluations are done with simulations in comparison of existing FR algorithms, ATM VBR and GFR policing algorithms, and the proposed algorithm.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1545-1554
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• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.50-64
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• 2016

Nowadays, smart meter (SM) technology is widely effectively used. In addition, power allocation (PA) and channel selection (CS) are considered problems with many proposed approaches. In this paper, we will suggest a specific scenario for an SM configuration system and show how to solve the optimization problem for transmission between SMs and the data concentrator unit (DCU), the center that collects the data from several SMs, via simulation. An efficient CS with PA scheme is proposed in the TV white space system, which uses the TV band spectrum. On the basic of the optimal configuration requirements, SMs can have a transmission schedule and channel selection to obtain the optimal efficiency of using spectrum resources when transmitting data to the DCU. The optimal goals discussed in this paper are the maximum capacity or maximum channel efficiency and the maximum allowable power of the SMs used to satisfy the quality of service without harm to another wireless system. In addition, minimization of the interference to the digital television system and other SMs is also important and needs to be considered when the solving coexistence scenario. Further, we propose a process that performs an interference analysis scheme by using the spectrum engineering advanced Monte Carlo analysis tool (SEAMCAT), which is an integrated software tool based on a Monte-Carlo simulation method. Briefly, the process is as follows: The optimization process implemented by genetic evolution optimization engines, i.e., a genetic algorithm, will calculate the best configuration for the SM system on the basis of the interference limitation for each SM by SEAMCAT in a specific configuration, which reaches the solution with the best defined optimal goal satisfaction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4902-4932
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• 2016

The popularity of network virtualization has recently regained considerable momentum because of the emergence of OpenFlow technology. It is essentially decouples a data plane from a control plane and promotes hardware programmability. Subsequently, OpenFlow facilitates the implementation of network virtualization. This study aims to provide an overview of different approaches to create a virtual network using OpenFlow technology. The paper also presents the OpenFlow components to compare conventional network architecture with OpenFlow network architecture, particularly in terms of the virtualization. A thematic OpenFlow network virtualization taxonomy is devised to categorize network virtualization approaches. Several testbeds that support OpenFlow network virtualization are discussed with case studies to show the capabilities of OpenFlow virtualization. Moreover, the advantages of popular OpenFlow controllers that are designed to enhance network virtualization is compared and analyzed. Finally, we present key research challenges that mainly focus on security, scalability, reliability, isolation, and monitoring in the OpenFlow virtual environment. Numerous potential directions to tackle the problems related to OpenFlow network virtualization are likewise discussed.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.403-408
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• 2014

In the Internet of Things(IoT) era, many of the things or objects that enclose our environments are able to associate with those things on the Internet. To construct IoT systems, it needs to consider a component for acquiring and aggregating of sensory data via things with sensors and instruments, which is connected by diverse networks, in IoT environment. An IoT system is intrinsically distributed in a variety of ways. In addition, to manage an IoT system efficiently, interoperability is needed to meet requirements while the IoT system is designed to deliver data among its applications. In this paper, a reference architecture based on asynchronous messaging is defined and used for designing an IoT system. To apply the architecture, we discuss how to manage data streams with real-time characteristics and make a prototype based on pipe-and-filter to produce and consume them by a pub/sub messaging system NaradaBrokering.

• Journal of Digital Convergence
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• v.16 no.11
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• pp.329-334
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• 2018

Web services are standardized software technologies that enable interoperability of operating systems and programming languages through networks and related standards. Web services are distributed computing services that provide and discover services making it possible to access various services. Since the search method of web service considers only the functional aspect, it has a limitation on user-oriented search when selecting a service. In order to solve these problems, this study proposes an automatic IoT information generation tool, and provides IoT extension information when searching a web service, thereby improving the problem so that a suitable service can be selected for a user. Automatic IoT extension information generation tool proposed in this study collects and stores various information generated in the process of sensing, networking, and information processing by collaborating autonomously in a distributed environment of user, object, and service. The proposed method supports the service search suitable for the user by providing the information generated by the user as extended information when searching the web service. The proposed method can be applied to the 4th industry sector to provide a customized service that meets various environment requirements.