• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.168-173
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• 2022

As the function of a product is advanced and the process is refined, the yield in the fine manufacturing process becomes an important variable that determines the cost and quality of the product. Since a fine manufacturing process generally produces a product through many steps, it is difficult to find which process or equipment has a defect, and thus it is practically difficult to ensure a high yield. This paper presents the system architecture of how to build a smart manufacturing system to analyze the big data of the manufacturing plant, and the equipment factor analysis methodology to increase the yield of products in the smart manufacturing system. In order to improve the yield of the product, it is necessary to analyze the defect factor that causes the low yield among the numerous factors of the equipment, and find and manage the equipment factor that affects the defect factor. This study analyzed the key factors of abnormal equipment that affect the yield of products in the manufacturing process using the data mining technique. Eventually, a methodology for finding key factors of abnormal equipment that directly affect the yield of products in smart manufacturing systems is presented. The methodology presented in this study was applied to the actual manufacturing plant to confirm the effect of key factors of important facilities on yield.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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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.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.461-470
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• 2014

This paper presents a probabilistic power flow (PPF) analysis method for distribution network incorporating the randomness and correlation of photovoltaic (PV) generation. Based on the multivariate kernel density estimation theory, the probabilistic model of PV generation is proposed without any assumption of theoretical parametric distribution, which can accurately capture not only the randomness but also the correlation of PV resources at adjacent locations. The PPF method is developed by combining the proposed PV model and Monte Carlo technique to evaluate the influence of the randomness and correlation of PV generation on the performance of distribution networks. The historical power output data of three neighboring PV generators in Oregon, USA, and 34-bus/69-bus radial distribution networks are used to demonstrate the correctness, effectiveness, and application of the proposed PV model and PPF method.

• Wind and Structures
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• v.28 no.2
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• pp.99-110
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• 2019

Vortex-Induced-Vibration (VIV) is one kind of the wind-induced vibrations, which may occur in the construction and operation period of bridges. This phenomenon can bring negative effects to the traffic safety or can cause bridge fatigue damage and should be eliminated or controlled within safe amplitudes.In the current VIV studies, one available mitigation countermeasure, the horizontal flow-isolating plate, shows satisfactory performance particularly in PI shaped bridge deck type. Details of the wind tunnel test are firstly presented to give an overall description of this appendage and its control effect. Then, the computational-fluid-dynamics(CFD) method is introduced to investigate the control mechanism, using two-dimensional Large-Eddy-Simulation to reproduce the VIV process. The Reynolds number of the cases involved in this paper ranges from $1{\times}10^5$ to $3{\times}10^5$, using the width of bridge deck as reference length. A field-filter technique and detailed analysis on wall pressure are used to give an intuitive demonstration of the changes brought by the horizontal flow-isolating plate. Results show that this aerodynamic appendage is equally effective in suppressing vertical and torsional VIV, indicating inspiring application prospect in similar PI shaped bridge decks.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3685-3693
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• 2021

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

• International Journal of Computer Science & Network Security
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• v.23 no.9
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• pp.141-149
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• 2023

Repacked mobile apps constitute about 78% of all malware of Android, and it greatly affects the technical ecosystem of Android. Although many methods exist for repacked app detection, most of them suffer from performance issues. In this manuscript, a novel method using the Constant Key Point Selection and Limited Binary Pattern (CKPS: LBP) Feature extraction-based Hashing is proposed for the identification of repacked android applications through the visual similarity, which is a notable feature of repacked applications. The results from the experiment prove that the proposed method can effectively detect the apps that are similar visually even that are even under the double fold content manipulations. From the experimental analysis, it proved that the proposed CKPS: LBP method has a better efficiency of detecting 1354 similar applications from a repository of 95124 applications and also the computational time was 0.91 seconds within which a user could get the decision of whether the app repacked. The overall efficiency of the proposed algorithm is 41% greater than the average of other methods, and the time complexity is found to have been reduced by 31%. The collision probability of the Hashes was 41% better than the average value of the other state of the art methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1551-1560
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• 2016

With the advancement of wearable devices and wireless body are networks, smart healthcare systems based on such technologies have been emerging to effectively monitor patient health and disease progression. In order to implement viable smart healthcare systems, the security and privacy of patient's personal health information must be considered. Yang et al. proposed a privacy-preserving authentication scheme using key-insulation technique for remote health monitoring system, however, key-insulation technique is not properly adapted to their scheme which in turn causes a security pitfall contrary to their assertions. Besides, Yang et al.'s scheme does not guarantee user anonymity against healthcare service provider. Therefore, in this paper, we discuss the security concerns for Yang et al.'s scheme and present an improved anonymous authentication scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.50-61
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• 2018

A precedent defense project study was carried out in the early stage of the project to support efficient determination of the acquisition method of the determined weapons system. A precedent study in the early stage of the project has been neglected, but lack of performance and increased costs are continuing problems. In a precedent study on a number of items within a limited time frame, expected risks during project implementation were not identified and reduced by failing to review the key review element in depth. Therefore, in this paper, we studied the application of the FTA/FMEA technique used in the system safety analysis process to identify key factors to be considered when carrying out the defense research project. The methodology for the development of the key review items was established through the improvement of the FTA/FMEA technique in order to meet specific conditions and given conditions. Based on the results of this study, we redefined core key factors in the precedent study stage, thereby eliminating unnecessary and anticipated risks that may arise in the future project management aspects of the defense project. It is anticipated that this will reduce costs and time in terms of the lifecycle of the weapon system and promote stable operation of the project through reduction of risk.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.991-998
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• 2012

This study considered NCW in the general as a key component of Future War and analyzed the international technical trend of tactical data link as the key of technical elements. The technique applied to Future War results from development of electronic communication and IT technique. However, NCW which plays a significant role in the Future War is not possible due to a development of simple technique but requires the amalgamative approach of various techniques essentially. That is, it should be understood and approached the management scenario and various techniques comprehensively. NCW is one of the areas which future electronic communication and IT can concentrate, so the government has been working for the developmental introduction of NCW strategically until 2020. Already, the level of localization of components related to electronics in military supplies exceeds 85%, but under the amalgamative research of technology in the high level like this, it would be possible to create new opportunities. Thus, the electronic communication and IT technology should seek effective applications of NCW by comprehending each area complexly.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.874-882
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• 2009

Continuous monitoring of dam performance is essential to earth and rockfill dams safety because it has to be guaranteed for safety during construction period of course and from initial impounding to a long term maintenance period of dam. Among the 31 dams managed by Kwater at present, the proportion of dams being over 20 years after completion of construction is 42% and it is estimated that the loss rate of monitoring devices will be increase as times. Monitoring devices would be impossible to repair since those are mostly installed in the dam body and foundation. If repairing of monitoring devices is possible, the expenditure will be expensive. Therefore reasonable decision making for abandonment, repair and alternation for loss of monitoring devices would be needed through the establishment of key instrument for earth and rockfill dam safety. In this study the process of monitoring for safety were modeled by failure modes of dams, adverse conditions related to failure mode, indicators of adverse condition and monitoring devices The relationship between failure mode and monitoring devices were systematically analyzed and established and evaluation technique for qualifying the importance of monitoring devices were presented.