• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1192-1197
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• 2000

Piping systems of the power generating stations have been generally protected by hydraulic and mechanical snubbers which can allow large displacements arising from temperature change while those can reduce or absorb stresses due to vibrations. However these snubbers require amounts of budget for maintenance or replacement because of the leakage, lubrication and finally short life cycle. Recently the snubbers consisted of wire rope have been proved to reduce vibrations of piping systems. While the wire rope snubbers are free of maintenance such as leakage and lubrication, imported price are so high. Now it is necessary to design, manufacture and certificate these wire rope snubbers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.226-237
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• 1998

In recent SATCOM systems, transparent transponders are widely used. The transponder is, however, the most vulnerable part in SATCOM systems against jamming interference. All signals within the transponder bandwidth are frequency-converted and retransmitted with IM(intermodulation) products. In this paper, the method is proposed that makes the SJR(Signal-to-Jammer ratio) better. The bandwidth spreading of the user signal can reduce the jammers effects. The geostationary satellite system is modeled to simulate and to certificate the capability of suppression of jammers by DSSS. If signal is partially-overlapped by jammer and PG(processing gain) is 16.9 [dB] for 2ASK jammer and about 16.8 [dB] for QPSK jammer, when BER is $10^{-3}$.

• The Journal of Information Systems
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• v.28 no.1
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• pp.115-132
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• 2019

Purpose The purpose of this study is to explain the agrophotovolatic system built by the Korea South-East Power Company and to propose methods to activate the agrophotovolatic system for the development of the renewable energy industry. Design/methodology/approach We conducted a three-step simulation in order to design a photovoltaic module, and we built the agrophotovolatic system based on the results of the simulation. Then, we analyzed the monthly generation of power and the rice harvests produced on farmland using the photovoltaic module. Based on the results of the analysis, we proposed institutional improvements to increase the use of the agrophotovolatic system, and we proposed new business models to increase the participation of farmers and business persons. Findings When we compared the agrophotovolastic system with the general photovoltaic system, we found that the agrophotovoltaic system had higher utilization rates and power generation. An analysis of rice produced on farmland using the photovoltaic module showed that more than 80% of the rice produced on general farmland was harvested. We suggested activation plans that involved the revision of the farmland law and the introduction of renewable energy certificate (REC). We also proposed a land lease model and a farmer participation model as two new business models, and we conducted economic evaluations and sensitivity analyses for both models.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3322-3347
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• 2021

Cloud Storage is the primary component of many businesses on cloud. Majority of the enterprises today are adopting a multicloud strategy to keep away from vendor lock-in and to optimize cost. Auditing schemes are used to ascertain the integrity of cloud data. Of these schemes, only the Provable Data Possession schemes (PDP) are resilient to key-exposure. These PDP schemes are devised using Public Key Infrastructure (PKI-) based cryptography, Identity-based cryptography, etc. PKI-based systems suffer from certificate-related communication/computational complexities. The Identity-based schemes deal with the exposure of only the auditing secret key (audit key). But with the exposure of both the audit key and the secret key used to update the audit key, the auditing process itself becomes a complete failure. So, an Identity-based PDP scheme with Parallel Key-Insulation is proposed for multiple cloud storage. It reduces the risk of exposure of both the audit key and the secret key used to update the audit key. It preserves the data privacy from the Third Party Auditor, secure against malicious Cloud Service Providers and facilitates batch auditing. The resilience to key-exposure is proved using the CDH assumption. Compared to the existing Identity-based multicloud schemes, it is efficient in integrity verification.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.77-87
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• 2002

In the field of secure information systems including electronic commercials, public key infrastructure(PKI) is widely used for secure services. The more PKI domains are established, the more needs we required for cross-domain certifications. Furthermore, each country has many certificate authorities(CA) which requires more complex cross certification. We may need a fast algorithm in order to fad the possible certification paths. This will be more indispensible in the growing PKI systems. Thus, in this paper we design a high-speed certification path discovery algorithm and implement it. Also we investigate the feature of operation of the system.

• Management & Information Systems Review
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• v.32 no.5
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• pp.157-174
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• 2013

In this research I investigate different firm characteristics between environment-friendly companies which are awarded by the Government and companies which violate environmental regulations. I set up three hypotheses in terms of managers' environmental attitude and firms' characteristic in technical, financial and structural aspects, considering environmental experts' opinions and findings of previous papers. Main research findings are as follows. First, both acquisition of the ISO 14001 certificate and ownership structure are used as proxy of top management attitude towards environmental decision-making. It is hypothesized that it is found that the certificates of ISO 14001 is a good proxy to represent top management environmental attitude and a firm with the certificate would have less likelihood of violation. Second, it is hypothesized that technical ability affects violation tendency of environmental regulations. It is found that as R&D investment increases, violation likelihood of environmetal regulations decrease. It can be conjectured that R&D investment may improve technical abilities of observing environment regulations. Third, it is investigated whether a firm's financial capability affects violation tendency of environmental regulations. Fourth structural aspects of a firm such as capital intensity, the number of employees and export ratio are investigated. It is found that a firm with more employees per sale amount tends to violate environmental regulations. It is not found any effects of expert ratio nor capital intensity on violation tendency of environmental regulation.

• Journal of Distribution Science
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• v.10 no.7
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• pp.23-31
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• 2012

The purpose of this study is to investigate existing world economic science theories and concepts of sustainable development as well as create original system of criteria and indicators to assess potential and conditions for sustainable development from a regional perspective and based on the above justify proposals for public authorities to improve methods of economic regulation for regional development. To achieve the goal evolution process of existing theories and concepts of sustainable development and "green growth" have been studied in terms of its adaptation to the spatial development of Kazakhstan, comparative dynamics of natural resources consumption in the Asia-Pacific region and Kazakhstan were investigated as well. Methodology. World best theory and practice methods for assessment of the level of sustainable development of the country and some of its territories were also studied. We selected the best system of criteria and indicators for assessment of economic, social and environmental sustainability of regional systems. Methods offered in this article are based on traditional and new factors of economic development and conditions for operation of regional systems. Indicators are chosen with a glance to basic goals for future development of regions in Kazakhstan. It is recommended to use two levels of methodology offered by author, namely national and regional, and at the local level later (districts, municipalities, cities). The results. Method offered by the author has been tested based on materials and statistics of regions in Kazakhstan. Suitability and usability of the proposed system of criteria and indicators for measuring of economic, social and environmental sustainability of regional systems was proved. Based on this analysis it was found out that there are regions in Kazakhstan that differ from each other by most of key indicators of sustainable regional development and this tendency is increasing. Conclusions and recommendations. As a result of this analysis, the authors have substantiated a number of proposals on methods of analysis to be used, improvement of methods of regional development, implementation of institutional reforms, as well as improvement of regional statistics. This article provides recommendations that can be successfully used in the management practices by public authorities to implement a new regional strategy focused on sustainable development in future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.952-960
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• 2007

Most Websites perform login process for authentication. But simple features like ID and Password have no trust because most people worry about appropriation. So the youth can easily access illegal media sites using other's ID and Password. Therefore this paper examine features be adaptable to authentication system, and propose a design of authentication system using multiple features. A proposed authentication system has two categories, such as low-level and high-level method. Low-level method consists of grant of authentication number through mobile phone from server and certificate from authority. High-level method combines ID/Password and features of fingerprint, character, voice, face recognition systems. For this, this paper surveys six recognition systems such as fingerprint, face, iris, character, vein, voice recognition system. Among these, fingerprint, character, voice, face recognition systems can be easily implemented in personal computer with low cost accessories. Usage of multiple features can improve reliability of authentication.

• The Journal of Sustainable Design and Educational Environment Research
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• v.9 no.1
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• pp.23-31
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• 2010

Recently, there are effects such as commercial investment and introducing new technology by introducing a BTL project. As a result, School's conditions are getting better and Numbers of certified schools are increasing, because the Green Building Certification Criteria was created in 2002 and expanded to schools in March, 2005. But the certificated schools just get the minimum score for certificate level 'good' about 65 points and there is no certificated school level 'very good'. The users of school stay in long time in the facility cause of the unique function of school. It means Indoor Environment Quality Criterion of the school is very important than any other criteria. Therefore, this study aims to analyze the indoor environment factor for the plan of the certificated school by green building rating systems. And this study also wants make the basement of a substantial technical application and development of the criteria in the plan for sustainable green school.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.211-218
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• 2020

Recently, with the advent of blockchain technology, attempts to apply this technology to existing systems are increasing. By using the blockchain technology consensus ledger and smart contract, it is necessary to distribute certificates to various fields that require documents, attestation, authentication, verification, etc. We are studying methods using hash operation, blockchain, etc., but it is difficult to spread the technology as it has not yet reached the stage of commercialization. In this paper, user device registration authentication algorithm, blockchain-based question and answer authentication algorithm, certificate issuance, verification process and encryption algorithm, and server-side authentication for easy application in blockchain based business platform environment We proposed a blockchain-based system authentication method using four algorithms.