• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권1호
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• pp.149-165
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• 디지털융복합연구
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• 제10권6호
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• pp.247-251
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• 2012

인터넷 응용프로그램을 통해 그룹 통신의 사용이 증가하면서 보안의 대한 요구사항인 메시지 무결성, 사용자 인증, 기밀성이 중요시 되고 있다. 보안 요구 사항을 위해서 그룹 통신 시에 암호 키를 생성하여 메시지 기밀성을 유지하는데, 키 생성을 효율적이면서도 안전하게 키 생성 트리를 이용하여 모바일 컴퓨팅 환경의 사용자도 쉽게 키를 생성하도록 사용자 재배치를 통해 키 생성 효율을 증대 시키기 위해 본 연구의 목표가 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권7호
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• pp.1737-1753
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.105-112
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• 2006

The main function of a reactor protection system is to maintain the reactor core integrity and the reactor coolant system pressure boundary. Generally, the reactor protection system adopts the 2-out-of-m redundant architecture to assure a reliable operation. This paper describes the safety assessment of a digital reactor protection system using the fault tree analysis technique. The fault tree technique can be expressed in terms of combinations of the basic event failures such as the random hardware failures, common cause failures, operator errors, and the fault tolerance mechanisms implemented in the reactor protection system. In this paper, a prediction method of the hardware failure rate is suggested for a digital reactor protection system, and applied to the reactor protection system being developed in Korea to identify design weak points from a safety point of view.

• 한국환경복원기술학회지
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• 제3권3호
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• pp.105-112
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• 2000

For the purpose of building up the construction prospects of highway in consideration of natural environment. The tree planting and flower seeding in highway road side using native species were offered to natural landscape and resting area landscaping for peoples, and these area were 194place. The tree planting and flower seeding activity is to improve driving circumstances, and to conserve living and natural environment along the highways. And, preparation of ecotone and biotope at the highway surroundings for natural ecosystem conservation is an important activity, and planting of natural plants is generally carried out near wildlife ecoroads in order to give the way for animals. The primary purpose of this tree planting and seeding is not only to reduce environmental pollution, but also to enhance the ecological surroundings of highway circumference. Ultimately, It is essential that the constructive method of highway think over such as ecological environment and road design, surveying and management, construction, highway maintenance etc.

• The Journal of the Acoustical Society of Korea
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• 제17권4E호
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• pp.11-16
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• 1998

For large vocabulary speech recognition using HMMs, context-dependent subword units have been often employed. However, when context-dependent phone models are used, they result in a system which has too may parameters to train. The problem of too many parameters and too little training data is absolutely crucial in the design of a statistical speech recognizer. Furthermore, when building large vocabulary speech recognition systems, unseen triphone problem is unavoidable. In this paper, we propose the modified phonetic decision tree algorithm for the automatic prediction of unseen triphones which has advantages solving these problems through following two experiments in Japanese contexts. The baseline experimental results show that the modified tree based clustering algorithm is effective for clustering and reducing the number of states without any degradation in performance. The task experimental results show that our proposed algorithm also has the advantage of providing a automatic prediction of unseen triphones.

• 한국조경학회지
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• 제21권1호
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• pp.51-61
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• 1993

Seeding treatment was used for 2 years at an artificial bare ground for selecting tree species suitable for forest-floor revegetation. 2 ${\times}$2${\times}$2 factorial experiment was used with a randomized complete block design for 19 native tree species and results were summarized as follows; 1. Native species suitable for restoration of bareland under 75% shading in central part of Korea were Styrax japonica, Styrax obassia, Smilax china, Callicarpa japonica, Stephanandra incisa, Viburnum dilatatum for. pilosulm, Magnolia sieboldii, Cornus kousa, Celastrus orbiculata, etc.. Especially, Magnolia sieboldii, Stephanandra incisa and Stryrax obassia were tolerant for forest-floor with hardened woil surface and Callicarpa japonica, Viburnum dilatatum for. pilosulum, Euonymus sieboldianus and Philadelphus schrenkii were suitable for softened soil surface with straw-mat mulching. 2. It is necessary to break seed dormancy to accelerate germination in case of Styrax obassia, Styrax japonica, Viburnum dilatatum for. pilosulum, Smilax china and Stephanandra incisa.

• 한국정보처리학회논문지
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• 제7권4호
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• pp.1184-1192
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• 2000

Multicast has communication mechanism that is able to transfer voice, video for only the specific user group. As compared to unicast, multicast is more susceptive to attack such as masquerading, malicious replay, denial of service, repudiation and traffic observation, because of the multicast has much more communication links than unicast communication. Multicast-specific security threats can affect not only a group's receivers, but a potentially large proportion of the internet. In this paper, we proposed the multicast security model that is able to secure multi-group communication in CBT(Core Based Tree), which is multicast routing. And designed the multicast key distribution protocol that can offer authentication, user privacy using core (be does as Authentication Server) in the proposed model.

• Asian Journal of Business Environment
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• 제4권2호
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• pp.5-11
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• 2014

Purpose - This study attempts to examine Islamic banking practices in Iran based on new scientific methods. Design, methodology, and approach - The study used financial ratios demonstrating healthy or non-healthy banks to assess the financial health of banks listed on the Tehran Stock Exchange. The assessment of these ratios with a decision tree as a non-parametric method for modeling is recommended to present this model. Information about the financial health of banks could affect the decisions of different groups of banks' financial report users including shareholders, auditors, stock exchanges, central banks, and so on. Results - The results of the study show that a decision tree is a strong approach for classifying Islamic banks in Iran. Conclusions - To date, several studies have been conducted in various countries on the topic of this study. Considering the importance of Islamic banking, this is one of the first studies in Iran the outcomes of the study may prove helpful to the Iranian economy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.254-254
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• 2000

This paper presents a genetic programming based evolutionary strategy for on-line adaptive learnable evolvable hardware. genetic programming can be useful control method for evolvable hardware for its unique tree structured chromosome. However it is difficult to represent tree structured chromosome on hardware, and it is difficult to use crossover operator on hardware. Therefore, genetic programming is not so popular as genetic algorithms in evolvable hardware community in spite of its possible strength. We propose a chromosome representation methods and a hardware implementation method that can be helpful to this situation. Our method uses context switchable identical block structure to implement genetic tree on evolvable hardware. We composed an evolutionary strategy (or evolvable hardware by combining proposed method with other's striking research results. Proposed method is applied to the autonomous mobile robots cooperation problem to verify its usefulness.