• Journal of Communications and Networks
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• 제14권6호
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• pp.640-652
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• 2012

Many studies have investigated the smart grid architecture and communication models in the past few years. However, the communication model and architecture for a smart grid still remain unclear. Today's electric power distribution is very complex and maladapted because of the lack of efficient and cost-effective energy generation, distribution, and consumption management systems. A wireless smart grid communication system can play an important role in achieving these goals. In this paper, we describe a smart grid communication architecture in which we merge customers and distributors into a single domain. In the proposed architecture, all the home area networks, neighborhood area networks, and local electrical equipment form a local wireless mesh network (LWMN). Each device or meter can act as a source, router, or relay. The data generated in any node (device/meter) reaches the data collector via other nodes. The data collector transmits this data via the access point of a wide area network (WAN). Finally, data is transferred to the service provider or to the control center of the smart grid. We propose a wireless cooperative communication model for the LWMN.We deploy a limited number of smart relays to improve the performance of the network. A novel relay selection mechanism is also proposed to reduce the relay selection overhead. Simulation results show that our cooperative smart grid (coopSG) communication model improves the end-to-end packet delivery latency, throughput, and energy efficiency over both the Wang et al. and Niyato et al. models.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.634-637
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• 2005

Hydrogen adsorption mechanism onto the porous metal-organic frameworks (MOFs) has been studied by density functional theory calculation. The selected functionals for the predict ion of interact ion energies between hydrogen and potential adsorption sites of MOF was utilized after the evaluation with the various functionals for interaction energy of $H_2C_6H_6$ model system the adsorption energy of hydrogen molecule into MOF was investigated with the consideration of the favorable adsorption sites and the orientations. We also calculated the second favorable adsorption sites by geometry optimization using every combination of two first absorbed hydrogen molecules. Based on the calculation of first and second adsorption sites and energies, the hydrogen adsorption into MOF follows a cooperative mechanism in which the initial metal sites initiate the propagation of the hydrogen adsorption on the whole frameworks. In addition, it was found that the interaction strength between the simple benzene ring with hydrogen is significantly reinforced when the benzene ring has been incorporated into the framework of MOFs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.2854-2874
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• 2015

This paper presents a game theoretic approach to analyze the public goods (PGs) allocation in peer-to-peer (p2p) networks. In order to reduce the free-riders and promote the cooperation among peers, we propose an incentive mechanism with cooperation-based game theory. In this paper, we regarded the contributed resources by cooperators as public goods (PGs). We also build the PGs allocation in P2P networks to be the optimization problem, and the optimal solution of PGs allocation satisfies the Bowen-Lindahl-Samuelson equilibrium. Firstly, based on the subscriber mechanism, we analyze the feasibility and prove the validity, which can achieve Nash equilibrium. However, this strategy cannot meet to Bowen-Lindahl-Samuelson equilibrium as the free-riders do not pay with their private goods for consuming the PGs. Secondly, based on the Walker mechanism, we analyze the feasibility and prove the validity for the same allocation problem, which meets to Bowen-Lindahl-Samuelson equilibrium and achieves Pareto efficiency within cooperative game. Simulations show that the proposed walker mechanism can significantly improve the network performance of throughout, and effectively alleviate free-riding problem in P2P networks.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.472-478
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• 2018

In this study, the sintering mechanism of woodceramics (WCs) from cashew nut shell waste (CNSW) was studied by analyzing chemical reactions and structural changes during the sintering process of of CNSW powder, liquefied wood and green bodies of WCs at $900^{\circ}C$ for 60 minutes in the $CO_2$ atmosphere. The chemical and structural properties of the products were investigated by X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared (FTIR), and scanning electron microscope (SEM). The results showed that the decomposition reactions of liquefied wood and CNSW occurred simultaneously to form the hard carbon and the soft carbon at high temperature. The sintering mechanism of WCs has been presented.

• 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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권3호
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• pp.916-937
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• 2023

Most of the existing Distributed Denial-of-Service mitigation schemes in Software-Defined Networking are only implemented in the network domain managed by a single controller. In fact, the zombies for attackers to launch large-scale DDoS attacks are actually not in the same network domain. Therefore, abnormal traffic of DDoS attack will affect multiple paths and network domains. A single defense method is difficult to deal with large-scale DDoS attacks. The cooperative defense of multiple domains becomes an important means to effectively solve cross-domain DDoS attacks. We propose an efficient multi-domain DDoS cooperative defense mechanism by integrating blockchain and SDN architecture. It includes attack traceability, inter-domain information sharing and attack mitigation. In order to reduce the length of the marking path and shorten the traceability time, we propose an AS-level packet traceability method called ASPM. We propose an information sharing method across multiple domains based on blockchain and smart contract. It effectively solves the impact of DDoS illegal traffic on multiple domains. According to the traceability results, we designed a DDoS attack mitigation method by replacing the ACL list with the IP address black/gray list. The experimental results show that our ASPM traceability method requires less data packets, high traceability precision and low overhead. And blockchain-based inter-domain sharing scheme has low cost, high scalability and high security. Attack mitigation measures can prevent illegal data flow in a timely and efficient manner.

• 한방재활의학과학회지
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• 제19권1호
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• pp.103-112
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• 2009

Objectives : This study was aimed to find out the physiological mechanism of craniosacral therapy, especially in CV4 technique and cranial rhythmic impulses. Methods : Recent studies were reviewed for cranial rhythmic impulses, and the ancient and present text were reviewed for the therapy of sub-occiput and cranial-suture part. Results and Conclusions : 1. Suboccipital muscles releasing may have made CV4 technique to effect. 2. The mechanism of the meridians of acupuncture and craniosacral system can be cooperative together in many parts of the clinical treatments. 3. Arterial vasomotor waves have a frequency similar to reports of cranial rhythmic impulses. The methods which have relation to heart rate variability, will be useful for the study of craniosacral therapy.

• 전자공학회논문지S
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• 제36S권6호
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• pp.67-75
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• 1999

자율분산로봇시스템에서 협조행동을 위한 로봇의 센싱과 통신 기능은 필수적이다. 일반적으로 대역적 통신시스템에서 로봇의 대수가 증가하면 통신자원의 제한과 정보의 범람이 발생한다. 따라서 이 경우 지역적 통신방법이 유리하다. 본 논문에서는 지역적 통신에 의한 정보의 전파를 해석하고 최적의 통신반경을 찾기 위한 3가지 방법을 제시한다. 또한 로봇이 정보를 획득하고 소실할 경우 발생하는 군의 카오스 행동을 피하기 위한 조건을 찾는다.

• 통상정보연구
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• 제10권2호
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• pp.391-410
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• 2008

Emphasis on relationship management might be found out from Williamson (1975), who tried to elucidate why an organization exists. According to his transaction cost theory, an organization is established to evade opportunistic actions of the market and build up a hierarchy of value chain. However, judged from the perspective of exchange relationship in a trade, the transaction cost theory was likely to approach to buyer-seller relationship by the mechanism of competition. Therefore, an organization exists to control the competition of the market. Relationship management suggested by relationship marketing focuses on cooperation between buyers and sellers, rather than competition against each other. Relationship management aims to provide a framework for making a market relationship that might become an asset or a resource of the firm. In the process of maintaining and strengthening long-term and cooperative relationship with all stakeholders included customers, suppliers and staff, they continue to create new values. The purpose of this empirical research, by investigating how relationship management of multinational enterprises influences on their competitive advantages and performances, is to suggest that a cooperative relationship established for a long time in the market, so-called quasi-market relationship, substitutes for an organization.

• 정보과학회 논문지
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• 제44권7호
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• pp.726-732
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• 2017

무선 센서 네트워크의 분산 센싱 및 예측에 대한 실제 Application에서 네트워크 환경 센싱 기능은 움직이는 소스 신호의 잡음 및 많은 센싱 정보들 때문에 매우 동적인 기능을 요구한다. 최근의 Distributed Online Convex Optimization 프레임워크는 분산된 방식으로 센서 네트워크를 통해 확률적인 학습 문제를 해결하기 위한 유망한 접근법으로 개발되었다. 기존의 Distributed Saddle Point Algorithm (DSPA)의 학습 결과에서 수렴 속도와 안정성은 이동성의 영향을 받을 수 있다. 이에 본 논문에서는 움직이는 소스 신호 시나리오의 동시 검출에서 예측을 안정화하고 보다 나은 수렵 속도를 달성하기 위해 통합 Sliding Windows 메커니즘을 제안한다.