• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1557-1564
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• 2020

In this paper, 3D model-based interactive gamma ray shielding package (MIGSHIELD) is developed in virtual reality platform for windows operating system. In MIGSHIELD, the computational methodology is based on point kernel algorithm (PK), several key parameters of PK are obtained using new technique and new methods. MIGSHIELD has interactive capability with virtual world. The main features made in the MIGSHIELD are (i) handling of physical information from virtual world, (ii) handling of arbitrary shapes radioactive source, (iii) calculating the mean free path of gamma ray, (iv) providing interactive function between PK and virtual world, (v) making better use of PK for virtual simulation, (vi) plug and play. The developed package will be of immense use for calculations involving radiation dose assessment in nuclear safety and contributing to fast radiation simulation for virtual nuclear facilities.

• 스마트미디어저널
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• 제13권4호
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• pp.94-103
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• 2024

안구 입력 시스템은 '아이트래킹 기술'과 '화상키보드 문자 입력 기술'을 기반으로 설계된 디지털 키보드 형식의 문자 입력 시스템이며, 이때 사용하는 화상키보드 구조는 직사각형의 QWERTY 배열로 양손 10개의 손가락을 동시에 활용하는 다중 입력 방식에 최적화된 구조이다. 하지만 '아이트래킹 기술'은 한 개의 초점만으로 입력해야 하는 안구운동 기반의 단일 입력 방식이기 때문에 다중 입력 방식인 직사각형 구조의 화상키보드와 함께 사용할 때 문제점이 발생한다. 이를 해결하고자 우선 안구에 연결된 근육의 형태와 종류 및 움직임에 관한 선행연구를 조사하였다. 그 후 안구의 동작원리가 직선이 아닌 원형으로 움직이는 것을 파악했다. 따라서 본 연구는 양손 입력에 최적화된 현재의 직사각형 구조로 배치된 화상키보드의 키 배열보다 회전운동에 적합한 원형 구조로 배치된 새로운 키 배열을 제안한다. 또한, 기존 직사각형 키 배열과 비교하여 원형 키 배열에 대한 성능 검증 실험을 진행하였고, 실험을 통해서 원형 배열의 키보드로 직사각형 배열 키보드를 대체 가능한지 확인하였다.

• 유통과학연구
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• 제18권2호
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• pp.5-15
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• 2020

Purpose : Today's retailers are integrating new VR technology into their new marketing strategies. Thus, this research aims to understand the role of virtual experiences in the circumstance of sales channels. Research design, data and methodology : Our model hypothesizes that five key factors determine the consumer experience of VR in the virtual retailing context: smartness, vividness, interactivity, playfulness, escape. Information access and flow are mediating variables that connect key drivers and VR satisfaction. Information access and flow then give influence to satisfaction towards VR. Satisfaction serves as a mediator that determines changes in consumer's dual intention: intention to revisit VR and intention to visit the real site. Results : According to the test results, every path except the relationship between information access and satisfaction of VR is accepted as expected at the significance level of 0.05. Conclusions : This research emphasizes the potential importance of VR and continue VR marketing research as an advent research area. Through the dual-path model, this study found that the primary function of VR is information access and flow experience. This result shows that most VR users value emotional benefits rather than rational benefits provided by VR. Finally, the satisfaction of VR can stimulate both the intention to use the VR and the intention to visit real mall.

• Journal of Microbiology and Biotechnology
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• 제32권4호
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• pp.504-513
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• 2022

Chitin deacetylase (CDA) inhibitors were developed as novel antifungal agents because CDA participates in critical fungal physiological and metabolic processes and increases virulence in soil-borne fungal pathogens. However, few CDA inhibitors have been reported. In this study, 150 candidate CDA inhibitors were selected from the commercial Chemdiv compound library through structure-based virtual screening. The top-ranked 25 compounds were further evaluated for biological activity. The compound J075-4187 had an IC50 of 4.24 ± 0.16 µM for AnCDA. Molecular docking calculations predicted that compound J075-4187 binds to the amino acid residues, including active sites (H101, D48). Furthermore, compound J075-4187 inhibited food spoilage fungi and plant pathogenic fungi, with minimum inhibitory concentration (MIC) at 260 ㎍/ml and minimum fungicidal concentration (MFC) at 520 ㎍/ml. Therefore, compound J075-4187 is a good candidate for use in developing antifungal agents for fungi control.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1556-1570
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• 2016

In the process of virtual inertia control (VIC), the frequency regulation capability of the directly-driven wind turbine with permanent-magnet synchronous generator (D-PMSG) on wind farm is related to its rotor kinetic energy and capacity margin. This paper proposes the method for assessing the D-PMSG frequency regulation capability and defining its coefficient according to the operating state of wind power generators. In addition, the calculating method of parameters in VIC is also discussed according to the principles of primary frequency regulation and inertia response of synchronous generators. Then, by introducing the capability coefficient into the proportion-differential virtual inertia control (PD-VIC) for power coordination, a coordinated virtual inertia control (C-VIC) strategy is developed, with the consideration of the difference in frequency regulation capability between wind power generators. The proposed control method can not only give full play to the frequency regulation capability of wind power generators, decrease the movements of the pitch angle control system but also bring some self-coordination capability to different wind power generators thus to avoid a secondary drop in system frequency. The simulations and experiments prove the proposed method to be effective and practicable.

• 정보보호학회논문지
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• 제25권1호
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• pp.5-15
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• 2015

초고속 인터넷과 무선통신망의 발달로 전자상거래는 급증하는 추세이다. 그러나 최근 이동통신사, 금융사 등의 해킹사건으로 인해 많은 수의 개인정보가 유출되었다. 특히 신용카드정보의 경우 온라인 거래에 악용되어 결제를 시도할 수 있고 이에 따른 피해는 카드소지자가 입게 된다. 이를 막기 위해 실제카드번호 대신 가상카드번호를 사용하는 기법들이 제안되었다. 하지만 기존의 제안들은 취약점이 존재하고 추가적인 보안 인프라가 필요하다. 본 논문에서는 기존에 제안된 가상카드번호 기법들을 분석하고 카드 사용자가 공개키/비밀키 키쌍을 생성하고 공개키를 카드사에 사전등록 함으로써 보안 요구사항을 충분히 만족시키면서도 추가적인 보안 인프라 없이 효율적으로 결제할 수 있는 가상카드번호 기법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2325-2349
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• 2014

Network virtualization technology plays a key role in cloud computing, which serves as an effective approach for provisioning a flexible and highly adaptable shared substrate network to satisfy the demands of various applications or services. Recently, the problem of mapping a virtual network (VN) onto a substrate network has been addressed by various algorithms. However, these algorithms are typically efficient for unicast service-oriented virtual networks, and generally not applicable to multicast service-oriented virtual networks (MVNs). Furthermore, the survivable MVN mapping (SMVNM) problem that considers the survivability of MVN has not been studied and is also the focus of this work. In this research, we discuss SMVNM problem under regional failures in the substrate network and propose an efficient algorithm for solving this problem. We first propose a framework and formulate the SMVNM problem with the objective of minimizing mapping cost by using mixed integer linear programming. Then we design an efficient heuristic to solve this problem and introduce several optimizations to achieve the better mapping solutions. We validate and evaluate our framework and algorithms by conducting extensive simulations on different realistic networks under various scenarios, and by comparing with existing approaches. Our simulation experiments and results show that our approach outperforms existing solutions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3841-3861
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• 2017

Virtualized small cell network is a promising architecture which can realize efficient utilization of the network resource. However, conventional full duplex self-backhauls lead to residual self-interference, which limits the network performance. To handle this issue, this paper proposes a virtual resource allocation, in which the residual self-interference is fully exploited by employing a physical-layer network coding (PNC) aided self-backhaul scheme. We formulate the features of PNC as time slot and information rate constraints, and based on that, the virtual resource allocation is formulated as a mixed combinatorial optimization problem. To solve the problem efficiently, it is decomposed into two sub problems, and a two-phase iteration algorithm is developed accordingly. In the algorithm, the first sub problem is approximated and transferred into a convex problem by utilizing the upper bound of the PNC rate constraint. On the basis of that, the convexity of the second sub problem is also proved. Simulation results show the advantages of the proposed scheme over conventional solution in both the profits of self-backhauls and utility of the network resource.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4950-4966
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• 2015

Cloud providers now face the problem of estimating the amount of computing resources required to satisfy a future workload. In this paper, a virtual machine provisioning (VMP) mechanism is designed to adapt workload fluctuation. The arrival rate of forthcoming jobs is predicted for acquiring the proper service rate by adopting an exponential smoothing (ES) method. The proper service rate is estimated to guarantee the service level agreement (SLA) constraints by using a diffusion approximation statistical model. The VMP problem is formulated as a facility location problem. Furthermore, it is characterized as the maximization of submodular function subject to the matroid constraints. A greedy-based VMP algorithm is designed to obtain the optimal virtual machine provision pattern. Simulation results illustrate that the proposed mechanism could increase the average profit efficiently without incurring significant quality of service (QoS) violations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1864-1876
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• 2016

Card-Not-Present (CNP) transactions taking place remotely over the Internet are becoming more prevalent. Cardholder authentication should be provided to prevent the CNP fraud resulting from the theft of stored credit card numbers. To address the security problems associated with CNP transactions, the use of a virtual card number derived from the transaction details for the payment has been proposed, instead of the real card number. Since all of the virtual card number schemes proposed so far are based on a password shared between the cardholder and card issuer, transaction disputes due to the malicious behavior of one of the parties involved in the transaction cannot be resolved. In this paper, a new virtual card number scheme is proposed, which is associated with the cardholder's public key for signature verification. It provides strong cardholder authentication and non-repudiation of the transaction without deploying a public-key infrastructure, so that the transaction dispute can be easily resolved. The proposed scheme is analyzed in terms of its security and usability, and compared with the previously proposed schemes.