• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.65-73
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• 2006

Network based VPN(Virtual Private Network) using MPLS(Multiprotocol Label Switching) technology, called PE(Provider Edge router) based MPLS VPN, is regarded as a good solution for intranets or ext3nets because of the low cost and the flexibility of the service provision. In this paper, we describe a mechanism that allows the VPN users to move from one site to another site of the VPN network based on the BGP-E MPLS technology. This mechanism is designed for PE(Provider Edge) routers of the backbone network. PE routers connected to the VPN sites establish a new MPLS path to the mobile node after they detect movement of the mobile VPN node. The new location may belong to the same VPN or to different VPN. We desisted VPN management and control functions of the PE routers in order to interface with the Mobile IP protocol and support the QoS mechanism. The pilot implementation and performance measurement were carried out on a simulation using COVERS tool.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.77-86
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• 2012

Avionics system are composed of multiple electronic device that performs important missions the number of electronic devices for the performance of aircraft has been gradually increasing. As a result, cost of development, maintenance and operating have increased. To solve this problem, technology paradigm of avionics has been shifting from federated avionics systems that manage to each system independently to IMA(Integrated Modular Avionics) systems. Unlike federated systems, fault tolerance becomes an essential technology in IMA systems. Because each aircraft features integrated in the an IMA system, a fault can jeopardize the entire system. In this paper, we define faults which can occur on the ARINC 653 based IMA system first, and design the ARINC 653 compliant HM(health Monitoring) system for the system can continue to operate be normal when occur a fault.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.82-89
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• 2011

The Proxy Mobile IPv6 is a network-based localized mobility management protocol. In the PMIPv6, Mobile Nodes are topologically anchored at a Local Mobility Anchor, which forwards all data packets for registered Mobile Nodes. Since all data packets destined for the Mobile Nodes a1ways traverse the Mobile Nodes's Local Mobility Anchor, the LMA might be bottleneck and the end-to-end de1ay are increased. Therefore, in this paper, we proposed an enhanced Route Optimization scheme in Multiple Local Mobility Anchors environment. In order to rapid1y detect Route Optimization, we designed Domain Information Table in Mobility Access Gateway. Furthermore, we use Correspondent Binding Cache in Local Mobility Anchor to maintain Route Optimization information during Mobile Nodes's handover. To solve packet loss and reodering problems during handover, we propose a new buffering and forwarding scheme.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.865-872
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• 2017

Recently, in response to the Internet age, the demand for hardware devices has been increasing, centering on the rapidly growing smart home field, due to the growth and management of sensor and control technology, mobile application, network traffic, big data management and cloud computing. In order to maintain the sustainable development of the hardware system, it is necessary to update the system, and the hardware device is absolutely necessary in real time processing of complex data (voice, image, etc.) as well as data collection. In this paper, we propose a method to simplify the control and communication method by integrating the hardware devices in two operating systems in a unified structure to solve the simultaneous control and communication method of hardware under different operating systems. The performance evaluation results of the proposed integrated hardware and the cloud control system connected to the cloud server are described and the main directions to be studied in the field of internet smart home are described.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.9-20
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• 2011

Most of domestic expansion joint system was applied by exposed expansion joint system. There are cases where it is damaged by driving. As the result noise and impact happened, and the social cost due to frequent repair works is increasing. So based on the Asphalt Plug Joint(APJ) system that applied in the United States and Europe, new buried expansion joint system was lately developed a system of Buried Folding Lattice Joint(BFLJ) that changed substructure. In this research, we have tested for durability and flexibility performance of buried expansion joint system that based on the type of asphalt mixture. Also we have evaluated for durability of BFLJ system against vehicle load using accelerated pavement testing. As a result of the experiment, the developed BFLJ system gives high flexibility performance and resolves transformation concentration along the joint section more than APJ system. Also it could be seen that the BFLJ system could overcome the disadvantages of APJ and prevent early damage. Because surface deflection of BFLJ system against vehicle load was measured low, and sub system in the buried expansion joint system was not damaged against vehicle load.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.89-100
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• 1998

A multi-user virtual reality system supports shared environments for concurrent accesses by multiple users. The performance of these systems depends heavily on the network environments. This paper experiments an effective network model for shared virtual environments. This model has a middle layer called groups placed between the server and its clients, and the tasks of server are distributed to these groups. Using groups solves some of the problems of existing systems such as lack of scalability, message overheads, and latency due to message passing among locally communicating entities in the virtual environment. Some experiments show lower overhead than existing distributed virtual environment systems in WAN as well as LAN environments. This model also supports a method that can be used to construct application specific network environments using message handler which allows user-defined message formats.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.410-419
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• 2003

The buffer cache of general operating systems such as Linux manages file data by using global block replacement policy and read ahead. As a result, multimedia data with a low locality of reference and various consumption rate have low cache hit ratio and consume additional buffers because of read ahead. In this paper we have designed and implemented a new buffer allocation algorithm for multimedia data on Linux. Our approach keeps one read-ahead cache per every opened multimedia file and dynamically changes the read-ahead group size based on the buffer consumption rate of the file. This distributes resources fairly and optimizes the buffer consumption. This paper compares the system performance with that of Linux 2.4.17 in terms of buffer consumption and buffer hit ratio.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.5
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• pp.385-393
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• 2004

Cluster systems have been widely used for solving problems in various application domains, and regarded as useful high performance computing resources. As the number of cluster system user is increasing, it is no less important to maintain stable operation than to improve cluster system performance. Although hardware preventive maintenance is important for keeping normal operation, the testing tool which can be used for general cluster systems during maintenance has received little attention. In this Paper, considering hardware Preventive maintenance, we suggest a testing tool for hardware of cluster system. The cluster system testing tool which is named CTS(Cluster system Test Suite) has two check routines; one for memory, and the other for NIC respectively. The CTS is designed to support the common features of general cluster systems and all the Jobs such as setting test conditions to querying the results can be done entirely within an integrated GUI environment. CTS is used as the testing tool for two kinds of cluster systems during maintenance, and the experimental results show that CTS reports useful information for cluster systems management.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.16-27
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• 2014

In this paper, we propose an efficient grid based routing scheme using the location information in order to reduce the routing cost in mobile ad-hoc networks. In our proposed scheme, all nodes can be a candidate to forward messages to the specified destination node and reduce the management cost of head nodes because they do not exist. The intermediate nodes determine the next hop relaying messages on the basis of location relations between a node and a grid zone. The proposed scheme explores the routing path considering the direction of a node using the coordinate of a grid zone and neighbor node information. It also maintains the routing path considering connectivities among the nodes. In order to show the superiority of the proposed routing scheme, we compare it with the existing grid based routing scheme in terms of the overhead of message, the success rate of transmission.

• Journal of the Korean Society of Safety
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• v.35 no.2
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• pp.8-16
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• 2020

In Article 311 of the Regulation on Occupational Safety and Health Standards requires the use of Korean Industrial Standards Act in accordance with the Industrial Standardization Act. However, the classification, inspection, maintenance, design, selection, and installation of explosion hazard locations for explosion and explosion prevention and internalization of 'safety' in the performance maintenance phase of electrical machinery and equipment There is no technical and institutional management plan for remodeling and alteration. Analysis of actual conditions and problems related to the installation, use, and maintenance of explosion-proof equipment, comparative analysis of domestic and international technical standards and systems, technical, institutional and administrative systems and systems related to installation, use, and maintenance of explosion-proof equipment, technical personnel and qualifications, etc. It is to propose legislation, system improvement, and technical standard establishment related to the maintenance of explosion-proof facility performance through improvement of the necessity and feasibility study for establishment of the legal status of the management site and management plan. As technical measures, KS standard revision (draft), KOSHA guide (draft) and explosion-proof facility performance maintenance manual were presented. In addition, the institutional management plan proposed the revised rule on occupational safety and health standards, the revised rule on the restriction of employment of hazardous work, and the manpower training program related to the maintenance of explosion-proof facilities and the qualification plan. Enhance safety at the installation, use, and maintenance stage of explosion-proof structured electrical machinery. It is expected to be used to classify explosion hazards, select related equipment, and to update and standardize standards related to installation, use and maintenance.