• Journal of Information Processing Systems
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• v.12 no.2
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• pp.275-294
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• 2016

A primary task in wireless sensor networks (WSNs) is data collection. The main objective of this task is to collect sensor readings from sensor fields at predetermined sinks using routing protocols without conducting network processing at intermediate nodes, which have been proved as being inefficient in many research studies using a static sink. The major drawback is that sensor nodes near a data sink are prone to dissipate more energy power than those far away due to their role as relay nodes. Recently, novel WSN architectures based on mobile sinks and mobile relay nodes, which are able to move inside the region of a deployed WSN, which has been developed in most research works related to mobile WSN mainly exploit mobility to reduce and balance energy consumption to enhance communication reliability among sensor nodes. Our main purpose in this paper is to propose a solution to the problem of deploying mobile data collectors for alleviating the high traffic load and resulting bottleneck in a sink's vicinity, which are caused by static approaches. For this reason, several WSNs based on mobile elements have been proposed. We studied two key issues in WSN mobility: the impact of the mobile element (sink or relay nodes) and the impact of the mobility model on WSN based on its performance expressed in terms of energy efficiency and reliability. We conducted an extensive set of simulation experiments. The results obtained reveal that the collection approach based on relay nodes and the mobility model based on stochastic perform better.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1431-1439
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• 2016

In this paper, we propose a new location service and location-based routing for data dissemination from a source to a mobile group sink in less energy consumption of the sensor node. Unlike the existing protocols, the proposed protocol uses a leader sink instead of a group area as the location information to represent a mobile sink group. The proposed protocol also uses grid leaders on virtual grid structure to support sink mobility in location service. By using a leader sink as a representative and grid leaders for mobility supporting, the proposed protocol can exploit an efficient hierarchical location service and data dissemination method without using flooding. Accordingly, the proposed protocol carries out upper layer location services and data dissemination between a leader sink and a source and lower layer location services and data dissemination between the leader sink and member sinks. Simulation results demonstrate that the proposed protocol achieves energy-efficiency.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.384-392
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• 2004

Mobile contents service providers have some difficulties to timely and proper service deployment due to rapid development cycle of diverse portable devices with different capabilities. A way to resolve the problem is to introduce a mobile contents service paltform that can adapt original mobile contents to diverse devices dynamically and automatically. In this paper, we propose a mobile contents service platform based on active network mechanisms, called Mobile Content Adaptation Network(MobiCAN). The MobiCAN node provides effective service deployment, execution, and maintenance features and accommodates service layering and service customization capabilities for easy deployment. The basic functional units of the MobiCAN node are micro services with well-defined service interfaces and service layering features. For reliable services among the MobiCAN nodes, we design new distributed and robust Overlay Management Protocols(OMPs). As an example of practical MobiCAN applications, we finally describe Dynamic Contents Customization Proxy(DCCP) service.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.9-22
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• 2006

When the legacy multicast routing protocols are adopted in If-based mobile core networks, there are some problems such as traffic injection from unnecessary sources, traffic overhead by group management and router performance degradation by large amount of multicast session information. In this paper, we propose a stateless multicast mechanism which has no need to maintain multicast information for session status and reduces redundant network overhead for maintaining multicast tree. In addition interworking with IGMPv3 gets rid of traffic from unnecessary sources which have no registration from receivers. The operations of essential components including a gateway node for interworking with the legacy Internet multicast network, a gateway node for transparency to radio access network and a intermediate node in mobile core networks, are definitely defined and the proposed communication architecture is completed. Finally we evaluate and approve the performance of the proposed architecture by means of well-designed network simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1230-1251
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• 2011

This document specifies a new IPv6 deployment protocol called CHANC, which stands for Configuring Hosts to Auto-detect (IPv6, IPv6-in-IPv4, or IPv4) Network Connectivity. The main part is an application level tunneling protocol that allows Internet Service Providers (ISPs) to rapidly start deploying IPv6 service to their subscribers whom connected to the Internet via IPv4-only access networks. It carries IPv6 packets over HTTP protocol to be transmitted across IPv4-only network infrastructure. The key aspects of this protocol are: offers IPv6 connectivity via IPv4-only access networks, stateless operation, economical solution, assures most firewall traversal, and requires simple installation and automatic configuration at customers' hosts. All data packets and routing information of the IPv6 protocol will be carried over the IPv4 network infrastructure. A simple application and a pseudo network driver must be installed at the end-user's hosts to make them able to work with this protocol. Such hosts will be able to auto-detect the ISP available connectivity in the following precedence: native IPv6, IPv6-in-IPv4, or no IPv6 connectivity. Because the protocol does not require changing or upgrading customer edges, a minimal cost in the deployment to IPv6 service should be expected. The simulation analysis showed that the performance of CHANC is pretty near to those of native IPv6, 6rd, and IPv4 protocols. Also, the performance of CHANC is much better than that of D6across4 protocol.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.270-281
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• 2003

ETF made the RFCs of MPLS technologies for providing the QoS of ATM or Frame Relay and the flexibility&scalability of IP on the Internet services. IETF has been expanding MPLS technologies as a common control component for supporting the various switching technologies called GMPLS. Also, IETF has standardized the signaling protocols based on such technologies, such as LDP, CR-LDP and RSVP-TE. ETRI developed the MPLS system based on ATM switch in order to provide more reliable services, differentiated services and value-added services like the VPN and traffic engineering service on the Korea Public Sector network. We are planning on deploying model services and commercial services on that network. This paper explains the basic functions of LDP, design and development of LDP on our system, and compares with LDP development and operation on other MPLS systems made by Cisco, Juniper, Nortel and Riverstone. In conclusion, this paper deduces the future services and applications by LDP through these explanation and comparison.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.23-30
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• 2012

In order to show the gap between theory and practice, this paper first gives some experimental results for theoretical and real neighbor sets on a test-bed sensor network. The results prove that existing management protocols (e.g., duty-cycling, routing or aggregation) based on the theoretical communication radius cannot achieve their original goal, efficiency. In this paper, we present a practical duty-cycling mechanism based on the real neighbor set, allowing for energy-efficiency. It also guarantees to suppress duplicated transmissions of sensing values with similarity within a specific threshold in each zone (i.e., a portion of intended divided network). Simulation results performed with a set of real sensor data show that our mechanism increases the network life time while guaranteeing the transmission of necessary sensing values.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.37-42
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• 2016

In this paper, in today's highly complex video and broadcast operations, broadcasters are constantly challenged to reliably deliver low-latency, high-quality video to multiscreen audiences on-air and online. The Adaptive Bit Rate (ABR) protocols enable internet video to a wide range of multiscreen devices. However, video quality is often marginal and would prove unacceptable for valued linear broadcast content delivered to the Big Screen today. The Media information processing technology advances in ABR enables service providers to take control and offer quality managed linear video services to ALL screens in the home, including the Big Screen, with a single unified IP Video infrastructure. The New Multiscreen-Assisted ABR (MSA-ABR) delivery management system proposed using Cloud based multicast-assisted ABR for a broadcast facility that performs routing of contribution content and online publishing services within a virtual, centralized cloud infrastructure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1363-1372
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• 2011

Flooding based routing protocols are usually used to disseminate information in wireless sensor networks. Those approaches, however, require message retransmissions to all nodes and induce huge collision rate and high energy consumption. In this paper, HoGoP (Hop based Gossiping Protocol) in which all nodes consider the number of hops from sink node to them, and decide own gossiping probabilities, is introduced. A node can decide its gossiping probability according to the required average reception percentage and the number of parent nodes which is counted with the difference between its hop and neighbors' ones. Therefore the decision of gossiping probability for network topology is adaptive and this approach achieves higher message reception percentage with low message retransmission than the flooding scheme. Through simulation, we compare the proposed protocol with some previous ones and evaluate its performance in terms of average reception percentage, average forwarding percentage, and forwarding efficiency. In addition, average reception percentage is analyzed according to the application requirement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.801-808
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• 2010

LEACH, one of hierarchical based routing protocols, was proposed for energy efficiency which is the most important requirement of Wireless Sensor Network(WSN). LEACH protocol is composed of a cluster of certain large number of clusters, which have a cluster head and member nodes. Member nodes send sensing data to their cluster heads, and the cluster heads aggregate the sensing data and transmit it to BS. The challenges of LEACH protocol are that cluster heads are not evenly distributed, and energy consumption to transmit aggregated data from Cluster heads directly to BS is excessive. This study, to improve LEACH protocol, suggests LECEEP that transmit data to contiguity cluster head that is the nearest and not far away BS forming chain between cluster head, and then the nearest cluster head from BS transmit aggregated data finally to BS. According to simulation, LECEEP consumes less energy and retains more number of survival node than LEACH protocol.