• World Technopolis Review
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• 제8권1호
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• pp.8-20
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• 2019

The intent of this paper is to identify key actors of a sustainable Smart City and define metrics that will allow assessment and better management of Sustainable Smart Cities. The paper is organized in two major segments. The first segment reviews the definition, six components, six action items of Smart Cities. It describes briefly a sample Smart City project and presents a selection of different dimensions along which Smart Cities are ranked and the rankings. The segment also discusses the technology architecture of a Smart City and then examines the definition and components of an innovation platform. The second presents the original contributions of the paper. It first introduces the dynamics created seven key actors of a Smart City ecosystem and describes their existing and potential contributions. It then defines Innopreneurship platform and presents a triple bottom line based quality metric to evaluate such a platform. This segment also discusses reengineering an economy and suggests a Smart City's Innovation Platform Score. The actions to be taken by the key actors of a Smart City in order to make it a Sustainable Smart City are described in several subsections. We hope these concepts and metrics will be a good starting point and will be refined over time by others.

• Journal of Power Electronics
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• 제17권1호
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• pp.172-180
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• 2017

The repetitive control (RC) strategy is widely used in AC power systems because of its high performance in tracking period signal and suppressing steady-state error. However, the dynamic response of RC is determined by the fundamental period delay $T_0$ existing in the internal model. In the current study, a ($nk{\pm}i$)-order harmonic RC structure is proposed to improve dynamic performance. The proposed structure has less data memory and can improve the tracking speed by n/2 times. $T_0$ proves the effectiveness of the ($nk{\pm}i$)-order RC strategy. The simulation and experiments of ($6k{\pm}1$)-order and ($4k{\pm}1$)-order RC strategy used in the voltage source inverter is conducted in this study to control the harmonic current source, which shows the validity and advantages of the proposed structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2719-2735
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• 2015

In the cloud environment, users pay more attentions to their data security since all of them are stored in the cloud server. Researchers have proposed many mutual authentication schemes for the access control of the cloud server by using the smart card to protect the sensitive data. However, few of them can resist from the smart card lost problem and provide both of the forward security and the backward security. In this paper, we propose a novel authentication scheme for cloud computing which can address these problems and also provide the anonymity for the user. The trick we use is using the password, the smart card and the public key technique to protect the processes of the user's authentication and key exchange. Under the Elliptic Curve Diffie-Hellman (ECDH) assumption, it is provably secure in the random oracle model. Compared with the existing smart card based authentication schemes in the cloud computing, the proposed scheme can provide better security degree.

• 정보보호학회논문지
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• 제30권3호
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• pp.313-323
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• 2020

최근 스마트 그리드 관련 기술의 발전으로 사용자는 다양한 환경에서 보다 안전하고 신뢰성 있는 전력 서비스를 제공 받을 수 있다. 그러나 이러한 서비스들은 인터넷을 통하여 제공되므로 공격자의 데이터 주입, 변경, 삭제 및 추출 등 다양한 잠재적인 공격에 취약하다. 따라서 올바른 사용자에게만 서비스를 제공하기 위한 사용자 인증하고 키를 합의 하는 것은 반드시 이루어져야 하는 보안 필수요소 이다. 본 논문에서는 Zhang 등이 제안한 인증 및 키 합의 방식이 안전성을 tamper-resistant 디바이스에 의존하는 문제가 있으며 스마트 미터 도난 및 위장 공격, 세션 키 노출 공격 등 다양한 공격에 취약함을 밝히고 이를 개선한 스마트 그리드 환경에서 변조 방지 디바이스를 사용하지 않으며 안전한 사용자 인증 및 키 합의 방식을 제안한다. 또한 제안된 인증 방식의 안전성 및 성능을 분석하고 BAN(Abadi-Burrow-Needham) logic 분석을 통하여 제안한 방식이 안전한 상호 인증을 제공함을 입증하였다. 따라서 제안된 방식은 효율적이고 안전하며 실제 스마트 그리드 환경에서 효율적으로 적용 가능한 인증 방식이다.

• 정보처리학회논문지C
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• 제10C권6호
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• pp.763-768
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• 2003

본 논문에서는 S/KEY 인증 프로토콜과 YEH와 SHEN, HWANG이 제안한 인증 프로토콜의 문지점을 개선하기 위하여 스마트 카드를 적용한 S/KEY 기반의 인증 프로토콜을 제안하였다. 제안프로토골은 SEED를 공유 비밀키로 적용하는 이들의 인증 프로토콜과 달리 공개키를 통해 S/KEY 인증 프로토콜을 개선하였다. 따라서 제안 프로토콜은 공유 비밀키 없이 서버를 인증하고 세션키를 분배 할 수 있다. 또한, 사용자의 암호 구문대신 임의로 생성된 강력한 비밀키를 적용하기 때문에 오프라인 사전 공격을 방지할 수 있다. 특히, 제안 프로토콜은 사용자의 비밀키 혹은 기타 비밀정보를 서버에 저장하지 않는 S/KEY 인증 프로토콜의 장점을 충실하게 만족할 수 있기 때문에 서버의 붕괴로 인해 사용자 로그인 정보가 유출되는 최악의 경우에도 유출된 정보를 통한 각종 공격에 대응할 수 있다.

• International Journal of Internet, Broadcasting and Communication
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• 제9권3호
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• pp.35-43
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• 2017

In 2013, Lee-Lie proposed secure smart card based authentication scheme of Zhu's authentication for TMIS which is secure against the various attacks and efficient password change. In this paper, we discuss the security of Lee-Lie's smart card-based authentication scheme, and we have shown that Lee-Lie's authentication scheme is still insecure against the various attacks. Also, we proposed the improved scheme to overcome these security problems of Lee-Lie's authentication scheme, even if the secret information stored in the smart card is revealed. As a result, we can see that the improved smart card based user authentication scheme for TMIS is secure against the insider attack, the password guessing attack, the user impersonation attack, the server masquerading attack, the session key generation attack and provides mutual authentication between the user and the telecare system.

• Journal of Power Electronics
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• 제19권5호
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• pp.1248-1258
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• 2019

This paper presents a moth-flame optimization (MFO)-based maximum power point tracking (MPPT) method for photovoltaic (PV) systems. The MFO algorithm is a new optimization method that exhibits satisfactory performance in terms of exploration, exploitation, local optima avoidance, and convergence. Therefore, the MFO algorithm is quite suitable for solving multiple peaks of PV systems under partial shading conditions (PSCs). The proposed MFO-MPPT is compared with four MPPT algorithms, namely the perturb and observe (P&O)-MPPT, incremental conductance (INC)-MPPT, particle swarm optimization (PSO)-MPPT and whale optimization algorithm (WOA)-MPPT. Simulation and experiment results demonstrate that the proposed algorithm can extract the global maximum power point (MPP) with greater tracking speed and accuracy under various conditions.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1332-1336
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• 2016

• Journal of Power Electronics
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• 제15권5호
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• pp.1338-1347
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• 2015

DC injection is a critical issue in transformerless grid-connected inverters. DC injection control based on virtual capacitor has the advantages of low cost, low loss, high accuracy and easy implementation. In this paper, the principle of DC injection control based on virtual capacitor was analyzed. In addition, the applicable conditions, working process, steady state error and advantages were also discussed in detail. The design of the control parameters based on virtual capacitor was proposed in a grid-connected inverter with LCL filter. The robustness of the control parameters was also discussed. Simulation and experimental results verify the validity of the analysis and demonstrate that this research has a certain value in engineering applications.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.989-995
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• 2017

As is known to all that the output of wind power generation has a character of randomness and volatility because of the influence of natural environment conditions. At present, the research of wind power prediction mainly focuses on point forecasting, which can hardly describe its uncertainty, leading to the fact that its application in practice is low. In this paper, a wind power range prediction model based on the multiple output property of BP neural network is built, and the optimization criterion considering the information of predicted intervals is proposed. Then, improved Particle Swarm Optimization (PSO) algorithm is used to optimize the model. The simulation results of a practical example show that the proposed wind power range prediction model can effectively forecast the output power interval, and provide power grid dispatcher with decision.