• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1822-1831
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• 2014

Micro-grid is connected to the main power grid through a static switch. One of the critical issues in micro-grids is protection which must disconnect the micro-grid from the network in short-circuit contingencies. Protective methods of micro-grid mainly follow the model of distribution system protection. This protection scheme suffers from improper operation due to the presence of single-phase loads, imbalance of three-phase loads and occurrence of power swings in micro-grid. In this paper, a new method which prevents from improper performance of static micro-grid protection is proposed. This method works based on artificial neural network (ANN) and able to differentiate short circuit from power swings by measuring impedance and the rate of impedance variations in PCC bus. This new technique provides a protective system with higher reliability.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.100-105
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• 1990

Associated with the protection and control functions in the substations, a new network scheme based on the IEEE 802.4 is proposed in this paper. This network is designed for supporting 3 data classes: 1st, it includes the highly time-critical data for the fault detection function. 2nd, routine data with a period is to served for monitoring the power status. Finally, it contains the control data which is used for reporting an event about protection or tuning some values related with power status. The way to allocate target_token_rotation timer is provided to guarantee the protection and control activities in the suggested network for the substation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.506-512
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• 2003

In this paper, a communication module between Relay agents in a multi-agent system based power distribution network protection system is realized using DNP3.0(Distributed Network Protocol), which is the standard communication protocol of distribution automation system in KEPCO. The key words for agent communication in the multi-agent based protection system are defined and represented by use of DNP application function code. The communication module developed based on the proposed communication scheme is tested by use of the Communication Test Harness, a test tool for DNP protocol, then used to the multi-agent system based power distribution net work protection system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.902-910
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• 2013

The most representative research network in Korea, KREONET, has developed DynamicKL, an advance reservation based Network Service Agent (NSA) for user driven virtual circuit services. DynamicKL provides reservation, provisioning, release, termination, and inquiry web services for network resources by using an open standard network service interface (NSI), as well as web services for network resources by using a GUI interface. In addition, it has the RICE interface to support a protection management function per VC for virtual circuits and reservations. In this article, a protection management per VC for provisioned VCs and reservations is addressed in the DynamicKL framework, as a contribution to the VC protection management issue, which results in more manageable and reliable VC services compared to other advance reservation frameworks. An administrator can detect successful or unsuccessful VC protections in the event of a primary link failure and successful or unsuccessful VC retrievals after a primary link repair, by using RICE.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.187-198
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• 2004

Virus protection infrastructure management is network infrastructure management, traffic route management, virus protection zone expansion, and virus protection management for gateway area. This research paper provides a diagnosis of characteristics and weaknesses of the structure of existing virus protection infrastructure, and recommends an improved multi-level virus protection infrastructure as a measure for correcting these weaknesses. Unproved virus protection infrastructure fitters unnecessary mail at the gateway stage to reduce the toad on server. As a result, number of transmission accumulation decreases due to the reduction in the CPU load on the Virus wall and increase in virus treatment rate.

• Convergence Security Journal
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• v.5 no.1
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• pp.53-62
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• 2005

Virus protection infrastructure managementis network infrastructure management, traffic route management, virus protection zone expansion, and virus protection management for gateway area. This research paper provides a diagnosis of characteristics and weaknesses of the structure of existing virus protection infrastructure, and recommends an improved multi-level virus protection infrastructure as a measure for correcting these weaknesses. Improved virus protection infrastructure filters unnecessary mail at the gateway stage to reduce the load on server. As a result, numberof transmission accumulation decreases due to the reduction in the CPU load on the Virus wall and increase in virus treatment rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1441-1451
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• 2000

There are two types of protection switching : a) automatic switching and b) forced switching. The switching mechanism is generally realised by OAM functions, therefore, the required OAM information field should be reserved in the PLOAM cells. This paper proposes an unidirectional and a bidirectional protection switching method and potential advantages. The unidirectional protection switching method can be faster than the bidirectional method because the unidirectional method does not require an APS protocol for protection switching. The bidirectional protection switching method uses APS K1 byte and K2 byte, which is included in octets of a PST message through downstream or upstream PLOAM cells, for protection switching. As making comparisons between the unidirectional and the bidirectional protection. switching method, this paper proposes an effective constructing method for ATM-PON network.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.11
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• pp.506-513
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• 2001

The islanding detection for distributed resources (DR) becomes an important and emerging issue in power system protection since the distributed generator installations are rapidly increasing and most of the installed systems are interconnected with distribution network. In order to avoid the negative impacts from islanding operations of DR on protection, operation and management of distribution system, it is necessary to effectively detect the islanding operations of DR and rapidly disconnect it from distribution network. Generally, it is difficult to detect islanding operation by monitoring only one system parameter This paper presents a new logic based islanding detection method for distributed resources(DR) which are interconnected with distribution network. The proposed method detects the islanding operation by monitoring four system parameter: voltage variation, phase displacement, frequency variation, and the variation of total harmonic distortion(THD) of current; therefore, it effectively detects island operation of DR unit operating in parallel with the distribution network. We also verified the efficiency of the proposed algorithm using the radial distribution network of IEEE 34 bus model.

• ETRI Journal
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• v.32 no.2
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• pp.184-194
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• 2010

Ethernet ring protection (ERP) technology, which is defined in ITU-T Recommendation G.8032, has been developed to provide carrier grade recovery for Ethernet ring networks. However, the filtering database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. This traffic overshooting is especially critical when a ring provides services to a large number of clients. According to our experimental results, the traditional FDB flush requires a link capacity about sixteen times greater than the steady state traffic bandwidth. This paper introduces four flush optimization schemes to resolve this issue and investigates how the proposed schemes deal with the transient traffic overshoot on a multi-ring network under failure conditions. With a network simulator, we evaluate the performance of the proposed schemes and compare them to the conventional FDB flush scheme. Among the proposed methods, the extended FDB advertisement method shows the fastest and most stable protection switching performance.

• Convergence Security Journal
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• v.13 no.1
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• pp.11-17
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• 2013

In this paper, the information security requirements in the mobile ad-hoc network(MANET) are presented, and the algorithm to establish the protection node(gateway) is proposed to prevent the distributed denial of service(DDoS). The information security technology and security threats in the MANET are presented, and protection node is decided to minimize the total cost through the sending nodes and receiving nodes by way of protection node. To set up the protection node, the minimization algorithms of maximum cost and the average cost between the protection node and receiving nodes are compared with the optimal solutions, in which optimal solution is found out by all enumeration method. From the results, the total cost between the sending and receiving nodes is minimized under the average cost minimization algorithm rather than the using of the maximum cost.