• 대한전기학회논문지:시스템및제어부문D
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• 제50권2호
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• pp.93-99
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• 2001

A new type geometric and mathematical network reduction model is introduced. Large-scale network is analyzed with analytic approach. The graph has many nodes, branches and loops. Circuit equation are obtained from these elements and connection rule. In this paper, the analytic relation between voltage source has a mutual different graphic property. Node-reduction procedure is achieved with this circuit property. Consequently voltage source value is included into the adjacent node-analyzing equation. A resultant model equations are reduced as much as voltage source number. Matrix rank is (n-1-k), where n, k is node and voltage source number. The reduction procedure is described and verified with geometric principle and circuit theory. Matrix type circuit equation can be composed with this technique. The last results shall be calculated by using computer.

• International Journal of Computer Science & Network Security
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• 제23권6호
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• pp.147-154
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• 2023

Network intrusion refers to any unauthorized penetration or activity on a computer network. This upsets the confidentiality, integrity, and availability of the network system. One of the major threats to any system's availability is a Denial-of-Service (DoS) attack, which is intended to deny a legitimate user access to resources. Therefore, due to the complexity of DoS attacks, it is increasingly important to abstract and describe these attacks in a way that will be effectively detected. The automaton theory is used in this paper to implement a SYN Flood detection system based on Time-Dependent Finite Automata (TDFA).

• 한국과학교육학회지
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• 제32권5호
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• pp.823-840
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• 2012

과학교육과정에서 과학의 본성은 교육의 중심에 있었으며, 특히 과학영재교육에서의 중요성은 더욱 크다고 할 수 있다. 그럼에도 불구하고 과학영재들의 과학의 본성에 대한 개념구조가 어떻게 형성되어있는지의 연구는 많지 않다. 이 연구에서는 언어 네트워크 분석법을 통해 중학교 과학영재의 사실, 가설, 이론, 법칙 그리고 과학적인 것의 의미에 대한 이들의 인식을 탐색하는 것을 목표로 하였다. 연구 목적 달성을 위해 개방형 검사지에서 얻은 응답들을 언어 네트워크 분석법을 통해 분석하였다. 연구 참여자들의 총 110명의 대학부설 과학영재교육원 소속 중학교 과학영재들이 연구에 참여하였으며 이들의 응답에 의해 5가지의 언어 네트워크를 얻었다. 네트워크 분석결과 이들이 인식하고 있는 사실은 증명여부와 실제성 문제, 가설은 잠정성과 불확실성, 이론은 실험에 의해 증명된 가설이라는 통념, 법칙은 절대성과 권위를 상징하는 언어들, 과학적인 것은 사실근거, 증명 가능여부, 정확하고 논리적인 이론체계 동반을 가장 중요한 인식의 핵으로 하고 있었다. 통합네트워크 분석결과, 연구에 참여한 중학교 과학영재들은 절대주의적이고 논리-실증주의적인 과학관을 형성하고 있는 것을 알 수 있었다. 이 연구에 활용된 언어 네트워크 분석법은 학습자의 보이지 않는 특정 내용을 어떤 방식으로 인식하여 개념구조를 형성하고 있는지 시각화하고, 학습자 개개인 및 지식별 통합적 정신모형을 구축하는데 유용할 것으로 기대된다.

• 인터넷정보학회논문지
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• 제15권2호
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• pp.109-127
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• 2014

본 연구는 기존의 표준관련 연구가 실제로 표준이 만들어지고 보급되는 제반 사회적 환경과 다중 이해관계자가 존재하는 복합적인 사회시스템에서의 행위자 역할 및 변화과정을 조망하는 작업이 충분히 이루어지지 못했다는 데에서 문제의식을 갖고 출발한다. 이를 배경으로 본 연구는 사회-기술적 제도 환경의 맥락에서 각기 다른 이해관계를 가진 참여자들이 혁신적인 기술을 개발해 표준화해가는 동태적 과정을 사회-기술적 접근으로 재구성하는 것을 목적으로 수행되었다. 이를 위한 세부 목표는 첫째, 표준화 과정을 둘러싼 사회-기술적 네트워크에서 인간 행위자 간, 인간과 비인간 행위자와의 상호작용 관계의 특징을 살펴보는 것이다. 둘째로는 표준화 과정을 선도한 핵심 행위자의 활동과 역할의 변화를 관찰하고자 하였다. 이를 위하여, 행위자-네트워크 이론(Actor Network Theory)에 기초하여 한국에서 진행된 고화질 3DTV방송기술의 표준화 과정의 동태적 속성을 분석하였다. 분석방법은 연구자가 행위자-네트워크에 직접 참여하여 동태적 특성을 분석하고, 설문 인터뷰와 심층 인터뷰를 통한 질적 연구의 방법을 적용, 표준 형성과정에 나타난 제반 환경-행위-기술 동학을 고찰하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3474-3497
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• 2016

Network Function Virtualization (NFV) and Software Defined Networking (SDN) are recently considered as very promising drivers of the evolution of existing middlebox services, which play intrinsic and fundamental roles in today's networks. To address the virtual service deployment issues that caused by introducing NFV or SDN to networks, this paper proposes an optimal solution by combining quantum genetic algorithm with cooperative game theory. Specifically, we first state the concrete content of the service deployment problem and describe the system framework based on the architecture of SDN. Second, for the service location placement sub-problem, an integer linear programming model is built, which aims at minimizing the network transport delay by selecting suitable service locations, and then a heuristic solution is designed based on the improved quantum genetic algorithm. Third, for the service amount placement sub-problem, we apply the rigorous cooperative game-theoretic approach to build the mathematical model, and implement a distributed algorithm corresponding to Nash bargaining solution. Finally, experimental results show that our proposed method can calculate automatically the optimized placement locations, which reduces 30% of the average traffic delay compared to that of the random placement scheme. Meanwhile, the service amount placement approach can achieve the performance that the average metric values of satisfaction degree and fairness index reach above 90%. And evaluation results demonstrate that our proposed mechanism has a comprehensive advantage for network application.

• 한국콘텐츠학회논문지
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• 제11권6호
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• pp.407-419
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• 2011

본 연구는 사회 정치적 관점에서 조직 내 지식이전에 영향을 미치는 요인을 탐색함으로써 지식 이전 프로세스를 설명하고자 한다. 지식의 흐름은 다양한 이해관계에 있는 개인과 집단 안에서 발생한다. 따라서 지식 이전 프로세스는 조직 내의 정치적 성향과 다양한 사회적 네트워크에 따라 영향을 미치게 된다. 본 연구는 사회정치학에서 이용되고 있는 조직 정치 이론과 사회적 네트워크 이론을 이용하여 지식 경영 프로세스에 미치는 영향에 대해서 연구하였다. 그 결과, 본 연구에서는 지식 이전 프로세스에 있어 조직 정치 성향과 사회적 네트워크관계인 내집단과 외집단 강도에 상호 유의한 의미가 있고 사회 네트워크가 지식 이전에 영향을 미치는 것을 실증적으로 발견하였다. 이뿐만 아니라 지식관리시스템이 조직 정치 성향에 따른 내집단 간의 관계 강화라는 부정적 효과를 상쇄하는 조절효과가 있음을 실증적으로 입증하였다.

• Journal of Communications and Networks
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• 제13권3호
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• pp.266-276
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• 2011

In wireless networks, it is well-known that intermediate nodes can be used as cooperative relays to reduce the transmission energy required to reliably deliver a message to an intended destination. When the network is under a central authority, energy allocations and cooperative pairings can be assigned to optimize the overall energy efficiency of the network. In networks with autonomous selfish nodes, however, nodes may not be willing to expend energy to relay messages for others. This problem has been previously addressed through the development of extrinsic incentive mechanisms, e.g., virtual currency, or the insertion of altruistic nodes in the network to enforce cooperative behavior. This paper considers the problem of how selfish nodes can decide on an efficient energy allocation and endogenously form cooperative partnerships in wireless networks without extrinsic incentive mechanisms or altruistic nodes. Using tools from both cooperative and non-cooperative game theory, the three main contributions of this paper are (i) the development of Pareto-efficient cooperative energy allocations that can be agreed upon by selfish nodes, based on axiomatic bargaining techniques, (ii) the development of necessary and sufficient conditions under which "natural" cooperation is possible in systems with fading and non-fading channels without extrinsic incentive mechanisms or altruistic nodes, and (iii) the development of techniques to endogenously form cooperative partnerships without central control. Numerical results with orthogonal amplify-and-forward cooperation are also provided to quantify the energy efficiency of a wireless network with sources selfishly allocating transmission/relaying energy and endogenously forming cooperative partnerships with respect to a network with centrally optimized energy allocations and pairing assignments.

• 한국정보통신학회논문지
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• 제17권12호
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• pp.2769-2774
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• 2013

유비쿼터스 센서 네트워크(Ubiquitous Sensor Network) 기술의 핵심은 저전력 무선 통신기술과 효율적 라우팅을 위한 적절한 자원할당 기술이다. 센서 네트워크에서 효율적인 자원할당을 위해서는 서비스에 따른 차별화된 자원할당 방식이 필요하다. 이를 위하여, 본 논문에서는 유선망에 사용되는 PQ(Priority Queue)와 WRR의 단점을 보완하여 USN에 적용이 가능한 스케줄러 알고리즘을 제안한다. 제안된 알고리즘은 센서 네트워크에서 각 클래스의 큐 상태를 체크하여 퍼지 이론을 적용한 제어 정책에 따라 WRR 스케쥴러의 가중치를 동적으로 할당하였다. 시뮬레이션 결과 제안된 알고리즘은 EF 클래스의 패킷 손실률에서 WRR 스케쥴러 방식보다 평균 6.5% 향상되었으며, AF4 클래스에서는 PQ 방식보다 평균 45% 향상된 결과를 보였다.

• Journal of Information Technology Applications and Management
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• 제27권6호
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• pp.197-224
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• 2020

Mobile games have become one of the most important driving forces of the game industry. We focus on the continuous intention to use Chinese mobile games from the perspective of experiential marketing and network externalities. We integrate user experience, network externalities and flow theory into expectation confirmation model and explore the influencing factors of continuous usage intention of Chinese mobile game and propose a research model. Game experience, service experience, perceived enjoyment, social interaction, challenge, perceived number of users and perceived number of peers were employed as independent variables, while flow, perceived value and satisfaction as mediating variables and continuous intention as the dependent variable. After surveying 426 samples, the model is tested with structural equation model. The results reveal that perceived enjoyment significantly positively influences perceived value, flow, satisfaction, and continuous intention. The greater the enjoyment of the game, the greater the satisfaction of the game and the greater the willingness to use it continuously. Game experience has a significant direct effect on continuous intention, which indicates that a better game experience can retain more users. Service experience and perceive number of peers positively influence satisfaction. Another finding is that social interaction and perceived number of users positively influence perceived value and flow, which indicate that social attributes are critical roles for retaining users. Game challenge also positively influences flow. The proper level of challenge is more likely to cause users to enter the state of flow. Flow indirectly influences continuous usage intention through the satisfaction of the game, which indicates that satisfaction is driven by flow experience and further retaining users. Empirical results implied that mobile game companies need to focus on improving user experience, expectation satisfaction and extending network externalities to improve the continuous intention of using mobile game.

• 디지털산업정보학회논문지
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• 제17권1호
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• pp.85-108
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• 2021

In this study, we would like to consider the main factors that influence psychological well-being by using social network service. suggest ways to use healthy social network services, and empirically verify how behavioral approaches, in other words self-determination theory, that deals with human psychological needs, affect psychological well-being by self-esteem and satisfaction to comprehensively examine the characteristics of service and user individuals and social influences, etc. First research result, it has been confirmed that the autonomy has a positive effect on self-esteem. Second, it has been confirmed that the autonomy does not have a positive effect on satisfaction. Third, it has been confirmed that the competence has a positive effect on self-esteem. Fourth, it has been confirmed that the competence does not have a positive effect on satisfaction. Fifth, it has been confirmed that the relationship has a positive effect on self-esteem. Sixth, it has been confirmed that the relationship does not have a positive effect on satisfaction. Seventh, it has been confirmed that self-esteem has a positive effect on psychological well-being. Eighth, it has been confirmed that self-esteem has a positive effect on satisfaction. Ninth, it has been confirmed that satisfaction has a positive effect on psychological well-being. These results mean that meeting basic human psychological needs has a significant impact on psychological well-being of the social network service users. In addition, it was confirmed that increasing the desire for autonomy, competence, relationship, which are factors of self-determination, is an important factor to enhance psychological well-being.