• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1057-1068
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• 2012

According to advance on vehicle technology, many kinds of ECU(Electronic Control Unit) are equipped inside the vehicle. In-vehicle communication among ECUs is performed through CAN(Controller Area Networks). CAN have high reliability. However, it has many vulnerabilities because there is not any security mechanism for CAN. Recently, many papers proposed attacks of in-vehicle communication by using these vulnerabilities. In this paper, we propose an wireless attack model using a mobile radio communication network. We propose a secure authentication mechanism for in-vehicle network communication that assure confidentiality and integrity of data packets and also protect in-vehicle communication from the replay attack.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1027-1035
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• 2012

Recently, the smart phone including web and mobile service based on the reliability and extendability of cloud computing is receiving huge attention. However, most of current cloud services provide just an application service for synchronizing data between mobile entity and server. Business model developed by communication companies have problems with interoperability. This paper proposes a new service security authentication model to efficiently manage smart phone users using different business models between smartphones and to keep the reliability and extendability of cloud computing. Proposed model authenticates for smart phone users to stay with in the unified communication with smart phone user's identity and access control to effectively use the current cloud computing system.

• Convergence Security Journal
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• v.8 no.3
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• pp.33-39
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• 2008

Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. In this paper, we discuss exponentially weighted moving average chart, in measuring failure time. In control, exponentially weighted moving average chart's uses are efficiency case of analysis with knowing information, Using real software failure time, we are proposed to use exponentially weighted moving average chart and comparative analysis of software failure time.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1262-1266
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• 1999

More precise operation and control is required to ensure the stability and security of modern large power systems that is a complicated and widely dispersed structure. To ensure the precise operation and control of modern power system, most of all, precise monitoring and measurement of the various state values of power system is required. This paper discusses phasor measurement unit using synchronization signals from the GPS satellite system- Synchronized Phasor Measurement Unit. Considering the power system operation state, the transmitting data format over modems is defined. To provide all available information, PMU process the measurements to generate three phase symmetrical component. This paper proposes the transmitted data format and implements the PMU model using EMTP/Models. The validity of proposed model is confirmed through several contingency on the simple power system.

• Convergence Security Journal
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• v.23 no.1
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• pp.125-137
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• 2023

Companies that handle sensitive information, led by public institutions, establish separate networks for work and the Internet and protect important data through strong access control measures to prevent cyber attacks. Therefore, systems that involve the junction where the Intranet(internal LAN for work purposes only) and the Internet network are connected require the establishment of a safe security environment through both administrative and technical measures. Mobile Device Management(MDM) solutions to control mobile devices used by institutions are one such example. As this system operates by handling sensitive information such as mobile device information and user information on the Internet network, stringent security measures are required during operation. In this study, a model was proposed to manage sensitive information data processing in systems that must operate on the Internet network by managing it on the internal work network, and the function design and implementation were centered on an MDM solution based on a network interconnection solution.

• Health Policy and Management
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• v.5 no.2
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• pp.173-201
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• 1995

A causal model of organizational commitment on the basis of Western literature was tested with a sample of 1,164 employees from two university hospitals in Korea. The model contains three groups of determinants : environmental variables(job opportunity, spouse support, and parent support), psychological variables(met expectations, work involvement, positive affectivity, and negative affectivity), and structural variables(job autonomy, work unit control, routinization, supervisor support, coworker support, role ambiguity, role conflict, workload, resource inadequacy, distributive justice, promotional chances, job security, job hazarda, and pay). The data were colleted with questionnaires and analyzed with the LISREL maximum likelihood method. It is found that (1) the following variables, listed in order of size, have significant total effects on organizational commitment : job satisfaction, met expectations, supervisor support, job security, routinization, job opportunity, negative affectivity, work involvement, distributive justice, and promotional opportunity, (2) the model explains fifty-nine percent of the variance in organizational commitment, and (3) the link with expectancy theory is justified by the results for met expectations. Two conclusions can be drawn from these findings. First, the model of organizational commitment appears to be generalizable to Korean hospitals. Second, the model of organizational commitment should include such theoretical variables as environmental, psychological, and structural factors.

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.684-698
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• 2004

The Hippocratic database model recently proposed by Agrawal et al. incorporates privacy protection capabilities into relational databases. Since the Hippocratic database is based on the relational database, it needs extensions to be adapted for XML databases. In this paper, we propose the Hippocratic XML database model, an extension of the Hippocratic database model for XML databases and present an efficient access control mechanism under this model. In contrast to relational data, XML data have tree-like hierarchies. Thus, in order to manage these hierarchies of XML data, we extend and formally define such concepts presented in the Hippocratic database model as privacy preferences, privacy policies, privacy authorizations, and usage purposes of data records. Next, we present a new mechanism, which we call the authorization index, that is used in the access control mechanism. This authorization index, which is Implemented using a multi-dimensional index, allows us to efficiently search authorizations implied by the authorization granted on the nearest ancestor using the nearest neighbor search technique. Using synthetic and real data, we have performed extensive experiments comparing query processing time with those of existing access control mechanisms. The results show that the proposed access control mechanism improves the wall clock time by up to 13.6 times over the top-down access control strategy and by up to 20.3 times over the bottom-up access control strategy The major contributions of our paper are 1) extending the Hippocratic database model into the Hippocratic XML database model and 2) proposing an efficient across control mechanism that uses the authorization index and nearest neighbor search technique under this model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.261-273
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• 2019

Recently, with the development of IT technology, there is an increasing interest in cloud services as the number of users using mobile devices such as mobile phones and tablets is increasing. However, there is a need for techniques to control or control various methods of accessing data as the user's service demands increase. In this paper, we propose a dual key based user authentication model that improves the user 's authentication efficiency by using two keys (secret key and access control key) to access the users accessing various services provided in the cloud environment. In the proposed model, the operation process and the function are divided through the sequence diagram of the algorithms (key generation, user authentication, permission class permission, etc.) for controlling the access right of the user with dual keys. In the proposed model, two keys are used for user authentication and service authorization class to solve various security problems in the cloud service. In particular, the proposed model is one of the most important features in that the algorithm responsible for access control of the user determines the service class of the user according to the authority, thereby shortening the management process so that the cloud administrator can manage the service access permission information of the user.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.151-166
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• 2009

To prove the integrity of digital evidence on the investigation procedure, the data which is using the MD 5(Message Digest 5) hash-function algorithm has to be discarded, if the integrity was damaged on the investigation. Even though a proof restoration of the deleted area is essential for securing the proof regarding a main phase of a case, it was difficult to secure the decisive evidence because of the damaged evidence data due to the difference between the overall hash value and the first value. From this viewpoint, this paper proposes the novel model for the mobile forensic procedure, named as "E-Finder(Evidence Finder)", to ,solve the existing problem. The E-Finder has 5 main phases and 15 procedures. We compared E-Finder with NIST(National Institute of Standards and Technology) and Tata Elxsi Security Group. This paper thus achieved the development and standardization of the investigation methodology for the mobile forensics.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.513-525
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• 2022

The immutability of blockchain is core elements of security of blockchain and guarantee data integrity. However, the characteristic that the data recoreded once in the blockchain cannot be modified has place for abuse by a specific user. In fact improper contents that is inappropriate to be recorded on the blockchain, such as harmful data and user personal data, is exposed on Bitcoin. As a way to manage improper content existing in the blockchain, there is a redactable blockchain using chameleon hash proposed for the first time by Ateniese. The redactable blockchain meet the right to be forgotten of GDPR by allowing data modification and deletion. Recently, Research on personal data management is being conducted in a redactable blockchain. Research by Jia et al. proposed a model that enables users to manage their personal data in the redactable blockchain. However, semi trusted regulators, which are blockchain participation nodes, have powerful authority in the blockchain, such as modification rights and deprivation of transaction rights for all blocks, which may cause side effects. In this paper, to weaken the authority of regulators in Y. Jia et al., we propose a method of authority subject altering and authority sharing, and propose a redactable blockchain-based authority change and access control system model based on applicable scenarios.