• Proceedings of the Korea Association of Information Systems Conference
• /
• 1997.10a
• /
• pp.25-36
• /
• 1997

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1992.04b
• /
• pp.202-202
• /
• 1992

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.45 no.4
• /
• pp.64-72
• /
• 2008

Researchers nowadays are trying to implement u-Healthcare (ubiquitous Healthcare) systems for real-time monitoring and analysis of patients' status through a low-cost and low-power wireless sensor network. u-Healthcare system has an aim to provide reliable and fast medical services for patients regardless of time and space by transmitting to doctors a large quantity of vital signs collected from sensor networks. Existing u-Healthcare systems can merely monitor patients' health status. However, it is not easy to derive physiologically meaningful results by analyzing rapidly vital signs through the existing u-Healthcare systems. We introduce a Grid computing technology for deriving the results by analyzing rapidly the vital signs collected from the sensor network. Since both sensor network and Grid computing use different protocols, a gateway is needed. In addition, we also need to construct a gateway which includes the functions such as an efficient management and control of the sensor network, real-time monitoring of the vital signs and communication services related to the Grid network for providing u-Healthcare services effectively. In this paper, to build an advanced u-Healthcare system by using these two technologies most efficiently, we design and present the results to implement a SensorGrid gateway which connects transparently the sensor network and the grid network.

• Journal of information and communication convergence engineering
• /
• v.6 no.2
• /
• pp.117-121
• /
• 2008

In ad hoc network, the scarce energy management of the mobile devices has become a critical issue in order to extend the network lifetime. Therefore, the energy consumption is important in the routing design, otherwise cluster schemes are efficient in energy conserving. For the above reasons, an Energy conserving Context aware Clustering algorithm (ECC) is proposed to establish the network clustering structure, and a routing algorithm is introduced to choose the Optimal Energy Routing Protocol (OERP) path in this paper. Because in ad hoc network, the topology, nodes residual energy and energy consuming rate are dynamic changing. The network system should react continuously and rapidly to the changing conditions, and make corresponding action according different conditions. So we use the context aware computing to actualize the cluster head node, the routing path choosing. In this paper, we consider a novel routing protocol using the cluster schemes to find the optimal energy routing path based on a special topology structure of Resilient Ontology Multicasting Routing Protocol (RODMRP). The RODMRP is one of the hierarchical ad hoc network structure which combines the advantage of the tree based and the mesh based network. This scheme divides the nodes in different level found on the node energy condition, and the clustering is established based on the levels. This protocol considered the residual energy of the nodes and the total consuming energy ratio on the routing path to get the energy efficiently routing. The proposed networks scheme could get better improve the awareness for data to achieve and performance on their clustering establishment and messages transmission. Also, by using the context aware computing, according to the condition and the rules defined, the sensor nodes could adjust their behaviors correspondingly to improve the network routing.

• Journal of Digital Convergence
• /
• v.11 no.12
• /
• pp.479-485
• /
• 2013

Virtualization is a promising approach to consolidating multiple online services onto a smaller number of computing resources. A virtualized server environment allows computing resources to be shared among multiple performance isolated platforms called virtual machines. Through server virtualization software, applications servers are encapsulated into VMs, and deployed with APIs on top generalized pools of CPU and memory resources. Networking and security have been moved to a software abstraction layer that transformed computing, network virtualization. And it paves the way for enterprise to rapidly deploy networking and security for any application by creating the virtual network. Stochastic reward net (SRN) is an extension of stochastic Petri nets which provides compact modeling facilities for system analysis. In this paper, we develop SRN model of network virtualization based on virtual switch. Measures of interest such as switching delay and throughput are considered. These measures are expressed in terms of the expected values of reward rate functions for SRNs. Numerical results are obtained according to the virtual switch capacity and number of active VMs.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.4
• /
• pp.81-87
• /
• 2016

With the rapid growth of the up-to-date smartphone and wireless network technologies, huge and various types of smart applications using these technologies are actively developed recently. Especially, multiplex types of smart applications using smartphone are developed and diffused with the rapid development of the ubiquitous sensor network technology using various sensors and the mobile computing technology that enables us to get network services at any time in any places. In this paper, we design a smart application that can accurately diagnose and process the current state of the local environment, objects, and persons remotely based on the context information such as local ecology, circumstances, medical or healthcare records and realtime sound or motion pictures using up-to-date samrtphone technology on the USN based mobile computing environment.

• Journal of KIISE:Information Networking
• /
• v.27 no.2
• /
• pp.149-159
• /
• 2000

In mobile computing environments, invalidation and propagation method based on broadcasting is used to transmit the information for cache maintenance of mobile hosts. Previous researches generally adopted invalidation method that easily adapts to the limited network bandwidth and the frequent disconnection. But the invalidation of frequently accessed data causes the contention on the wireless network with the increasing cache requests. Although the propagation method can reduce the cache requests, the high probability of broken message or loss of message is the main factor that degrades the system performance. To resolve these problems, we propose adaptive cache maintenance scheme that dynamically adjusts the broadcasting ratio of invalidation and propagation, according to the wireless network connection states. The proposed scheme broadcasts the propagation message in stable connection state, so it can reduce the cache requests and server response time. With the decreasing available network bandwidth by the frequent partial disconnection and disconnection, the proposed scheme dynamically increases the broadcasting ratio of the invalidation messages to minimize the broken message or the loss of message probability. Consequently, the proposed scheme resolves the problems which arise in the invalidation or propagation method in mobile computing environments.

• Journal of Korea Game Society
• /
• v.12 no.3
• /
• pp.59-68
• /
• 2012

This paper describes the design and implementation of a network-adaptive N-screen game system to be used in cloud computing. The system we are considering needs to generate game video in a cloud server and transmit the video to multiple game devices over an in-home wireless network via a home game server. It is difficult to support multiple screens which have different resolutions with a single bitstream of game video. Therefore, we developed a new network-adaptive game-video extraction and transmission method using (1) scalable video coding and (2) Raptor code techniques. The simulation, conducted with real game-video, verified the efficiency of the proposed video streaming system.

• IEIE Transactions on Smart Processing and Computing
• /
• v.1 no.1
• /
• pp.34-49
• /
• 2012

Recently, the smart grid (SG) has been introduced to solve the serious network issues caused by the increasing electrical demand and the complex nonlinear nature of the electric power distribution network. The SG, regarded as the next generation power grid, can transmit power in more efficient ways by building an automatic and distributed energy delivery network. In this paper, we first assess how various existing networking technologies, such as IEEE 802.11 (WiFi) and IEEE 802.15.4 (ZigBee), meet the requirements of the SG communication protocols. Specifically, we classify the existing network protocols into three categories: WSN-based networking, WiFi-based networking, and wireline-based networking. We then survey the security issues regarding the SG. Finally, we propose an agile SG networking architecture and show the effectiveness of different adopted networking technologies and, as a result, present a candidate solution to implement agile networking in SGs.

• Convergence Security Journal
• /
• v.6 no.1
• /
• pp.105-110
• /
• 2006

Home Gateway which composes Home network in Ubiquitous Computing environment is an equipment to provide the connection with the external Internet Physically, and it carry out the role which communication, control and monitor is important. But Home gateway has potential threats because it connected on external Internet as spillage user's information from outside wrongdoers. Consequently, Home gateway has to have security module and structure for the communication which is sate. In this research paper, We designed Home gateway security structure for the communication which is protected when computer user use the computer from the outside to home to send information or important data.