• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.608-617
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• 2011

ubiquitous network management system (u-NMS) is the network management system based on smartphone which are recently of wide use. The purpose of the u-NMS is to provide convenience for network administrator utilizing the mobility of smartphone and to manage the network efficiently. This paper proposes the smart NMS agent and the mobility management server (MMS). The smart NMS agent enables to use the monitoring web server and remote control application on the smartphone in wireless network. The MMS is developed to reduce the problems such as handover latency and packet loss, which can be taken place in wireless network. The network manager can monitor traffic in real time through the smart NMS agent and remotely control the network efficiently when sudden failures happen in the u-NMS. In this paper, performance evaluation is carried out with our test-bed system implemented. We focus on the measurement of the MMS performance. When the MMS is compared to previous mobility management protocol, our mobility management server reduces the average latency up to 65% in initial access, handover latency and processing delay to the network management center.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.8-17
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• 2008

Since different methods or protocols have been used to manage various mobile terminals, it has been difficult to manage mobile terminals efficiently. OMA(Open Mobile Alliance), therefore, proposed OMA DM(Device Management) as a standard for device management. In this paper, in an effort to apply the OMA DM concept ta real application area a home-delivery service management system using OMA DM agents is designed and implemented. The home-delivery service management system is developed using SyncML Tool Kit 4.3, SK WIPI SDK and Embedded Visual-C++ under the environment of SK-WIPI Clet. Since the home-delivery service management system is developed using OMA DD which is expected to be installed in most of the mobile terminals, separate lower level program modules for the management system would not be necessary. In order to justify this world some experiments are performed using SK WIPI emulator 1.1., which provides the same execution environments as a real mobile terminals does. Experiments show that the home-delivery service management system developed in this paper, works properly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.382-389
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• 2007

In this paper we report the development of mobility test bed, the realization of basic protocol that supports L3 mobility and the measurement of performance parameters that can affect handover performance. Previously proposed mobility management system, BBM (Break Before Make) method such as MIPV6 and Fast MIPV6, uses one interface in wireless network. In this method, to connect to new AP, it first disconnects existing AP and tries to connect to new AP. This can cause packet loss for the traffic vulnerable to delay such as VoIP. To provide seamless handover between different wireless networks, we propose MBB (Make Before Break) handover method having two network interfaces. Comparative study of previous method and proposed method on mobility and handover was conducted under simulated real environment on the test bed. Almost no packet loss was found with newly proposed method. In conclusion, it is shown that mobility protocol with proposed handover method can be applied to the application services sensitive to delay and packet loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.746-754
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• 2007

In this paper, we propose a fast handoff algorithm for micromobility management enhancement in HMIPv6 networks, which eliminates the DAD procedure involved in the regular HMIPv6 in order to o decrease handoff latency and increase the resource utilization efficiency. In the proposed scheme, the MAP is designed to guarantee the uniqueness of MN's interface identifier within a MAP domain as long as the MN moves in a MAP domain, so that the MN configures the new address without the DAD procedure resulting in the decreased handoff latency significantly When the MN resides in a subnet, MIPv6 is used adaptively as a mobility management protocol, which is to reduce bandwidth waste from the IP packet header overhead of IP-in-IP tunneling from the regular HMIPv6. We evaluate the performance of the proposed handoff micromobility algorithm in terms of handoff delay and packet loss thru computer simulation. Thru various computer simulation results, we verified the superior performance of the proposed scheme by comparing with the results of other schemes, MIPv6 and HMIPv6.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.339-345
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• 2014

This study has a purpose that improves efficiency of energy management and adaptation followed by movement of node better than the various early studied routing techniques. The purpose of this paper is the technique that uses RSSI value and location of sensor that is received by each sensor node to routing. This sduty does not save node information of 1-hop distance. And it solves energy-inefficient traffic problem that happens during data exchange process for middle node selection in close range multi hop transmission technique. The routing protocol technique that is proposed in this study selects a node relevant to the range of transmission which is set for RSSI value that is received by each node and selects the closest node as a middle node followed by location data. Therefore, it is for not exhaustion of node's energy by managing energy efficiently and cutting data transmission consuming until the destination node.

• Journal of Energy Engineering
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• v.18 no.3
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• pp.147-155
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• 2009

Demand for distributed source by new and renewable energy has been gradually increasing recently. For the characteristics of distributed generation, distributed source is located near the distribution system and customers' buildings and can be operated in standalone mode or in interface mode with distribution system. When the distributed sources are interfaced with distribution system, the standard for interfacing distributed source with existing distribution system and operation manual should be updated with revisions in order to manage the distributed source effectively and operate the distribution system stably because how to operate the interfaced system is different from that of existing distribution system. In this paper, the FEP(Front End Processor) using the international standard protocol IEC-60870 for interfacing with distributed resources was designed. The designed system was verified via the test result using main control system for distributed generation and RTU(Remote Terminal Unit) for interface with distributed power generating.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1411-1419
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• 2017

The two factor authentication capability, private key possession and key protection password knowledge, and the strong public key cryptography protocol of PKI authentication have largely contributed to the rapid construction of Internet transaction trusted infrastructure. The reusability of a certificate-based identity for every PKI site was another contribution factor of the spread of PKI authentication. Nevertheless, the PKI authentication has been criticised mainly for the cost of PKI construction, inconvenience of individual certificate management, and difficulties of password management. Recently FIDO authentication has received high attention as an alternative of the PKI authentication. The FIDO authentication is also based on the public key cryptography which provides strong authentication services, but it does not require individual certificate issuance and provides user-friendly and secure authentication services by integrating biometric technologies. The purpose of this paper is to concretely compare the PKI-authentication and FIDO-authentication and, based on the analysis result, to propose their corresponding applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3865-3871
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• 2014

The U-health service provides medical services with patients anytime or anywhere and is defined as the service that combines information and communication technology with health and medical service. However, it causes some troubles, such as the disclosure of patients' medical information or data spills (personal information extrusion). Moreover, it has the weak point of the security threats associated with data based on existing wire-wireless systems because it conducts data transmission and reception through the network. Therefore, this paper suggests a safe personal information management system by designing integrated certification schema that will help compensate for the weaknesses of the U-health service. In the proposal, the protocols for user information, certification between medical institution and users, data communication encryption & decryption, and user information disuse were designed by applying the ID-Based Encryption, and analyzed such existing systems and PKI Based-based communication process, securely and safely.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.125-135
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• 2003

In this paper, we developmed and implemented router and bandwidth broker that provides end-to-end QoS in differentiated service IP networks. Our design goal is to provide end-to-end premium service using the EF PHB. The bandwidth broker and router were implemented in the FreeBSD 4.6 platform. For the DiffServ router, we implemented QoS daemon, rollback managment routine, monitoring, and COPS-PR client. Also, Ive implemented bandwith broker which has SLS and resource management function, and signaling protocols for interfacing intra-and inter-domain. On the testbed, we have validated and evaluated the performance of the implemented DiffServ router and bandwidth broker using the inter-domain signaling protocol client in MS Windows platform. The test results show that the end-to-end QoS can be guaranteed for the inter-domain diffServ by the implemented system.

• The KIPS Transactions:PartC
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• v.11C no.5
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• pp.703-710
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• 2004

WebDAV is a protocol to support collaboration among one or more groups in geographically distant locations through the internet. WebDAV extends the web communication protocol HTTP/1.1 to provide a standard infrastructure for .supporting asynchronous collaboration for various contents across the internet. A WebDAV client uses HTTP requests to perform a renewal and update action to the resources in WebDAY servers. So, it is desirable that the client supports the ability of authoring and version management with a good concurrency control and property management. In this paper, to enhance usability, we developed a .NET-based WebDAV client with a user interface similar to the Windows Explorer. The developed WebDAV client supports easy launching of the authoring application and appropriate lock control for the server resources. In addition, through the functionality of process monitoring, it supports automatic update of the server resources when the modification of the resources are completed by the user. The WebDAY client is a .NET-based application written in the C＃ language, running on any platform supporting a .NET framework.