• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.175-182
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• 2006

The CGA proposed by IETF working group prevents address spoofing and stealing and provides digital signature to users, but key collision problem arises. To solve this critical problem, the CGA defines the SEC field within address format, which is set to high value when high security is required and vice versa, but the CGA faces a dilemma between security and the processing time. As SEC value increases, the processing time to generate the CGA grows dramatically while key collision ratio increases if low SEC value is applied to the CGA. We propose modified CGA (MCGA) that has shorter processing time than the CGA and offers digital signature with small overheads. To solve key collision problem, we employ hierarchical ad hoc network. The MCGA is applicable to IPv6 networks as well public networks. In this paper, we design a mathematical model to analyze the processing time for MCGA and CGA first and evaluate the processing time via simulations, where the processing time for MCGA is reduced down 3.3 times when SEC value is set to 0 and 68,000 times when SEC value is set to 1. Further, we have proved that the CGA is inappropriate for both ad hoc networks and IPv6 networks when the SEC field is set to more than 3.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.571-575
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• 2004

Having age of ubiquitous ahead, existing IPv4's address space insufficiency phenomenon appears because of increasing network usage as well as multimedia data transmission becomes much, necessity of new IP address system that guarantee QoS are needed. IPv6 was made to solve these problem. IPv6 solves address space insufficiency phenomenon offering by 128bit address space, and also offers hierarchical address layer that support improved QoS. IPv6 defines relation between surrounding node using Neighbor Discovery protocol. Used Neighbor Discovery messages, grasp surrounding node, include important informations about network. These network information outcrops can give rise in network attack and also service that use network will paralysis. Various kinds of security limitation was found in Present Neighbor Discovery protocol therefore security function to supplement tris problem was required. In this thesis, Secure Neighbor Discovery protocol that add with security function was design and embody by CGA module and SEND module.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.151-159
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• 2013

This paper reviewed the relationship between internal marketing(management support, education, pay system, internal communication, employment security) and food safety climate(prevention, superior attitude, work condition), and the moderating effect of employment type(permanent or temporary employees) in food service company. Based on the responses from 304 responses, the results of hierarchical multiple regression analysis showed that 4 factors(management support, education, internal communication, employment security) effect positively on food safety climate(prevention, superior attitude, work condition). The positive effect of internal communication on superior attitude and work condition appeared to be more positive in permanent employees than in temporary employees. And the results of t-test analysis showed that permanent employees perceived more positively all internal marketing factors(management support, education, pay system, internal communication, employment security) and food safety climate(precaution, superior attitude, work condition) than temporary employees.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.724-728
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• 2002

This paper considers a security framework for geographic information System(GIS). The GIS is an information system for supporting fast decision associated spacial problems and the system has a role of infra structure of the information system. The security is also one of the major technology for information system. However, researches on secure GIS are presented little and this paper considers the secure GIS. This paper suggest a framework for the secure GIS based on derived requirements on the secure system. Analysis on security for a serial, parallel and hierarchical secure system is also added.

• Convergence Security Journal
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• v.5 no.4
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• pp.49-58
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• 2005

We propose a specific ubiquitous sensor network (USN) architecture as a promising candidate of the future telemedicine model which offers the patient's mobility and more cost-efficient medical care system. This new USN architecture is a kind of cell-based secure sensor network supporting encrypted multi-casting communications and it has a hybrid routing protocol by adapting flat routing to hierarchical routing. For the patient's privacy and the protection of patient's vital information from eavesdropping, we adopt a lightweight PKI-based secure communication protocol with some formal presentation on its core procedure.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.774-777
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• 2013

2012년 Das 등은 계층적 무선 센서 네트워크를 위한 동적 패스워드 기반 사용자 인증 스킴을 제안하였다. 그러나 Das 등이 제안한 동적 패스워드 기반 사용자 인증 스킴은 패스워드 추측 공격에 대한 취약성이 있다. 따라서 본 논문에서는 Das 등이 제안한 동적 패스워드 기반 사용자 인증 스킴을 분석하고, Das 등의 인증 스킴이 패스워드 추측 공격에 안전하지 못함을 증명한다. 또한 패스워드 길이에 따른 패스워드 추측 공격에 대한 공격시간을 분석한다.

• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.21-28
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• 2007

Hierarchical Mobile IPv6 improves performance of Mobile IPv6 by managing Binding Update in terms of location, With improved handover delay, realization of delay-sensitive services (e,g, VoIP or video streaming) has become more persuadable, Comparing with Mobile IPv6, however, Hierarchical Mobile IPv6 brings security threats related to Local Binding Update to mobile network, In the RFC 4140, specific methods to authenticate Local Binding Update message are not explicitly presented. It is essential that design secure architecture to address problems related to authenticating Local Binding Update, Many secure suggestions for Local Binding Update, however, concentrate on infrastructure-based solutions such as AAA PKI. These approaches may cause scalability problem when the suggested solutions are applied to real network. Therefore we suggest authentication method that doesn't require infrastructure, In addition to authentication of Local Binding Update, our method also provides mobile node with power saving ability.

• Wind and Structures
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• v.39 no.1
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• pp.1-14
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• 2024

Widespread damages from extreme winds have attracted lots of attentions of the resilience assessment of power distribution systems. With many related environmental parameters as well as numerous power infrastructure components, such as poles and wires, the increased challenge of power asset management before, during and after extreme events have to be addressed to prevent possible cascading failures in the power distribution system. Many extreme winds from weather events, such as hurricanes, generate widespread damages in multiple areas such as the economy, social security, and infrastructure management. The livelihoods of residents in the impaired areas are devastated largely due to the paucity of vital utilities, such as electricity. To address the challenge of power grid asset management, power system clustering is needed to partition a complex power system into several stable clusters to prevent the cascading failure from happening. Traditionally, system clustering uses the Binary Decision Diagram (BDD) to derive the clustering result, which is time-consuming and inefficient. Meanwhile, the previous studies considering the weather hazards did not include any detailed weather-related meteorologic parameters which is not appropriate as the heterogeneity of the parameters could largely affect the system performance. Therefore, a fragility-based network hierarchical spectral clustering method is proposed. In the present paper, the fragility curve and surfaces for a power distribution subsystem are obtained first. The fragility of the subsystem under typical failure mechanisms is calculated as a function of wind speed and pole characteristic dimension (diameter or span length). Secondly, the proposed fragility-based hierarchical spectral clustering method (F-HSC) integrates the physics-based fragility analysis into Hierarchical Spectral Clustering (HSC) technique from graph theory to achieve the clustering result for the power distribution system under extreme weather events. From the results of vulnerability analysis, it could be seen that the system performance after clustering is better than before clustering. With the F-HSC method, the impact of the extreme weather events could be considered with topology to cluster different power distribution systems to prevent the system from experiencing power blackouts.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.661-672
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• 2008

Mobile Ad-hoc NETwork is a kind of self-controlled network composed only of mobile hosts. Since its range of use is gradually expanding into various sections applicable to practical lives, active researches are being conducted on it. However, as it depends on cooperation of nodes composing the entire network, due to weakness of wireless link and lack of its central infrastructure, so it is exposed to more serious risk than general network in security. Therefore, this paper proposes Cluster-Based Dynamic Authentication that enables only reliable nodes to participate in communication, by solving lack of centralized infrastructure, using hierarchical Mobile Ad hoc NETwork structure based on cluster, and by complementing security weakness through mutual authentication between hierarchical nodes. Simulation shows that the proposed scheme can complement security weakness of Mobile Ad hoc NETwork and that it is more adequate in reliability and expandability than the existing schemes.

• The Journal of Society for e-Business Studies
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• v.10 no.1
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• pp.121-134
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• 2005

The MANET has many problems in security despite of its many advantages such as supporting the mobility of nodes, independence of the fixed infrastructure, and quick network establishment. In particular, in establishing security, the traditional certification service has many difficult problems in applying to the MANET because of its safety, expandability, and availability. In this paper, a secure and effective distributed certification service method was proposed using the Secret Sharing scheme and the Threshold Digital Signature scheme in providing certification services in the MANET. In the proposed distributed certification service, certain nodes of relatively high safety among the mobile nodes consisting of the MANET, were set as privileged nodes, from which the process of issuing a certification started. The proposed scheme solved problem that the whole network security would be damaged by the intrusion to one node in the Centralized Architecture and the Hierarchical Architecture. And it decreased the risk of the exposure of the personal keys also in the Fully Distributed Architecture as the number of the nodes containing the partial confidential information of personal keys decreased. By the network simulation, the features and availability of the proposed scheme was evaluated and the relation between the system parameters was analyzed.