• Journal of Power Electronics
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• v.15 no.1
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• pp.235-245
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• 2015

This paper proposes a reactive current assignment and control strategy for a doubly-fed induction generator (DFIG) based wind-turbine generation system under generic grid voltage sag or swell conditions. The system's active and reactive power constrains during grid faults are investigated with both the grid- and rotor-side convertors (GSC and RSC) maximum ampere limits considered. To meet the latest grid codes, especially the low- and high-voltage ride-through (LVRT and HVRT) requirements, an adaptive reactive current control scheme is investigated. In addition, a torque-oscillation suppression technique is designed to reduce the mechanism stress on turbine systems caused by intensive voltage variations. Simulation and experiment studies demonstrate the feasibility and effectiveness of the proposed control scheme to enhance the fault ride-through (FRT) capability of DFIG-based wind turbines during violent changes in grid voltage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.4
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• pp.1538-1552
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• 2021

Machine learning models are vulnerable to adversarial examples generated by adding a deliberately designed perturbation to a benign sample. Particularly, for automatic speech recognition (ASR) system, a benign audio which sounds normal could be decoded as a harmful command due to potential adversarial attacks. In this paper, we focus on the countermeasures against audio adversarial examples. By analyzing the characteristics of ASR systems, we find that frame offsets with silence clip appended at the beginning of an audio can degenerate adversarial perturbations to normal noise. For various scenarios, we exploit frame offsets by different strategies such as defending, detecting and hybrid strategy. Compared with the previous methods, our proposed method can defense audio adversarial example in a simpler, more generic and efficient way. Evaluated on three state-of-the-arts adversarial attacks against different ASR systems respectively, the experimental results demonstrate that the proposed method can effectively improve the robustness of ASR systems.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.785-792
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• 2024

This article provides an overview of the design methodology used to develop a conceptual set of reactivity control mechanism of a micro reactor based on the U-Battery. The U-Battery is based on remote deployment and therefore it is favourable to provide a long fuel lifecycle. This is achieved by implementing a high fissile loading content, which proves challenging when considering reactivity control methods. This article follows the design methodology used to overcome these issues, with an emphasis on a new concept of a moveable moderator which utilises the size of the U-Battery as a small reduction in moderation provides a significant reduction in reactivity. The latest work on this project sees the moveable moderator investigated during a depressurised loss of forced coolant accident, where a reduction of moderator volume increases the maximum fuel temperature experienced. The overall conclusion is that the maximum fuel temperature is not significantly increased (4 K) due to the central reflector region relatively lower volumetric heat capacity compared to that of whole core. However, a small temperature increase is observed immediately after the transient due to the central reflector removal because it reaches energy equilibrium with the fuel region faster.

• International Journal of Quality Innovation
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• v.7 no.2
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• pp.50-68
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• 2006

Innovation fuels organizations evolving them to withstand rapid changes in markets and challenges from competition. While diversified concepts of innovation are examined, a generic framework for managing organizational innovation is established to portray the notion in a methodical approach. Substantiation of the determinants for organizational innovation is carried out in order to examine the framework against the practical situation. Subsequently, expectations and actual accomplishments of the determinants for organizational innovation from the industry are determined so as to understand the industrial view towards the framework. This paper summarizes the empirical findings of a survey of organizational innovation with a sample of 208 electronic and electrical manufacturing companies in the Greater Pearl River Delta (GPRD), China. On one hand, the survey findings confirm the readiness of the generic framework from the practical perspective of the industry. On the other hand, rankings are obtained for the expected importance and company accomplishment of the determinants for organizational innovation, namely in the areas of management leadership and commitment, employee capability and attitude and strategy development for innovation. The improvement area is also verified by the shortcomings of the expectation in comparison to the company accomplishment in each determinant. Meanwhile, it is believed that a directional attitude towards the determinants can facilitate the accomplishment of the determinants of organizational innovation. Further results will be generated from a more in-depth analysis of variables. The confirmed framework will be further developed into an assessment system for organizational innovation with the support of best practices in each determinant.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.58-73
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• 2021

Cloud Service Providers (CSPs) enable their users to access Cloud computing and storage services from anywhere in quick and flexible manners through the Internet. With the basis of 'pay-as-you-go' model, it makes the interactions between CSPs and the users play a vital role in shaping the Cloud computing market. A pool of virtualized and dynamically scalable Cloud services that delivered on demand to the users is associated with guaranteed performance and cost-provisioning. It needed a costing scheme for determining suitable charges in order to secure lease pricing of the Cloud services. However, it is hard to meet the satisfied prices for both CSPs and users due to their conflicting needs. Furthermore, there is lack of Service Level Agreements (SLAs) that allowing the users to take part into price negotiating process. The users may lose their interest to use Cloud services while reducing CSPs profit. Therefore, this paper proposes a generic costing scheme for Cloud services using General Equilibrium Theory (GET). GET helps to formulate the price function for various services' factors to match with various demands from the users. It is initially determined by identifying the market circumstances that a general equilibrium will be hold and reached. Specifically, there are two procedures of agreement made in response to (i) established equilibrium supply and demand, and (ii) service price formed and constructed in a price range. The SLAs in our costing scheme is integrated to satisfy both CSPs and users' needs while minimizing their conflicts. The price ranging strategy is deliberated to provide prices' options to the users with respect their budget limit. Meanwhile, the CSPs can adaptively charge based on users' preferences without losing their profit. The costing scheme is testable and analyzed in multi-tenant computing environments. The results from our simulation experiments demonstrate that the proposed costing scheme provides better users' satisfaction while fostering fairness pricing in the Cloud market.

• Nuclear Engineering and Technology
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• v.27 no.2
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• pp.203-215
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• 1995

A continued operation of RCPs during a certain small break LOCA may increase unnecessary inventory loss from the RCS causing a severe core uncovery which might lead to a fuel failure. After TMI-2 accident, the CEOG developed RCP trip strategy called “Trip-Two/Leave-Two” (T2/L2) in response to NRC requests and incorporated it in the generic EPG for CE plants. The T2/L2 RCP trip strategy consists of tripping the first two RCPs on low RCS pressure and then tripping the remaining two RCPs if a LOCA has occurred. This analysis determines the RCP trip setpoint and demonstrates the safe operational aspects of RCP trip strategy during a small break LOCA for YGN 3&4. The trip setpoint of the first too RCPs for YGN 3&4 is calculated to be 1775 psia in pressurizer pressure based on the limiting small break LOCA with 0.15 ft$^2$ break size in the hot leg. The analysis results show that YGN 3&4 can maintain the core coolability even if the operator fails to trip the second too RCPs or trips at worst time. Also, the YGN 3&4 RCP trip strategy demonstrates that both the 10 CFR 50.46 requirements on PCT and the ANSI standards 58.8 requirements on operator action time can be satisfied with enough margin. Therefore, it is concluded that the T2/L2 RCP trip strategy with a trip setpoint of 1775 psia for YGN 3&4 can provide improved operator guidance for the RCP operation during accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.435-445
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• 2018

This study analyzed factors that should be considered in the process of export diversification strategy formulation and priorities of strategies. We reviewed the extant literature and interviewed six experts. Cross-sectional analysis of a literature review and interview results were used to determine the influencing factors of export. The data for this study were collected from a survey of 68 export experts in Automotive Parts enterprises. Data were analyzed using AHP. As a result of the analysis, the order of importance appeared in the order of internal capacity, correlation buyer effect, entry barriers, technology response, and competition environment. The regions with a high overseas level were product differentiation, centralization, and low cost, whereas those with a low level were in the order of low cost, product differentiation, and concentration. It is meaningful to review the alternatives for adoption of the export diversification strategy and establish a strategy appropriate to the situation. It is necessary to establish a customized strategy considering the characteristics of the global region, and not only internal competence but also mutual relationship with local buyers are important.

• Journal of Korea Game Society
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• v.9 no.2
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• pp.59-68
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• 2009

This study empirically analyzes game engine supplier's licensing strategy connected with supplier's technological regime and technological innovation. The results show that game engine supplier's technological regime is heterogeneously differentiated and it's user friendliness increases. "User Friendliness" of supplier's technological regime enables supplier's efficient technological transfer and increases supporting capability. Technological knowledge factors such as modularity of game engine structure, generic capability, codifiability of tacit game engine knowledge and degree of innovation turn incomplete technological market into efficient technological market by increasing supporting capability and by reducing transaction cost.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.607-610
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• 2004

It is still not sufficient for the famous embedded software test methods such as Finite State Machine, Software Cost Reduction and model coverage based test case generation, to pinpoint where bugs hang around and to figure out what makes the bugs. A new approach to ameliorate the drawbacks is proposed in this paper. In the approach, we define a generic model for embedded software. And we also define failure mechanism for embedded software, and a way to generate test cases based on it.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.116-125
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• 2012

Local pharmaceutical companies in Korea, which have grown focusing on domestic markets, have recently faced difficulties such as market saturation, price control policies and market-opening pressures by FTA. It seems to be an urgent issue for them to export pharmaceuticals to developed countries comprising the greater part of the global pharmaceutical market. Hence, this research was conducted to investigate and benchmark the strategies employed by India industry for the successful access to the global pharmaceutical markets. Drug policies as well as their influences on pharmaceutical market changes between India and Korea for the last 40 years have been searched and the differences have been comparatively analyzed. The pharmaceutical industry of India has the following strengths: low costs; experienced labor pool; excellent reverse-engineering skills; powerful IT; marketing capability; and established distribution network. After 2000, consolidations, M&A and alliances with domestic and multinational companies have been sharply increased in the industry of India. Indian companies unfolding both competition and cooperation with multinational corporations currently move up the value-added chain, and this enthusiastic strategy should be learned by local pharmaceutical companies.