• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.355-356
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• 2015

This paper proposes a control strategy of total output power ripple cancellation for both of Machine-Side Converter (MSC) and Grid-Side Converter (GSC) in a DFIG under unbalanced grid conditions. The proposed control strategy for the MSC is the zero torque ripple control algorithm with an enhanced LVRT capability. The control algorithm for the MSC exhibits reduced torque pulsation in steady-state unbalanced grid conditions. In addition, this control algorithm also minimizes a peak value of rotor current in transient unbalanced grid conditions. The total output power ripple cancellation control algorithm is adopted in the GSC. The total output power ripple cancellation is achieved by nullifying the oscillating component of the total output active and reactive power at the summing point of stator and rotor of DFIG. The proposed control strategy for the GSC reduces the output power oscillation leading to the improved quality of wind farms output.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.175-177
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• 1994

In the overmodulation region, the operation of the three phase induction motor with a current controller is characterized by a rapid deterioration of the motor torque and speed. It is desirable to use the overmodulation strategy that extends the normal operating range even in this case. In this paper, a new overmodulation strategy is proposed for the high performance motor drives and the comparison study with two conventional methods are also described. In the proposed strategy, considering the motor dynamics, a suitable voltage vector is selected in order to extend the stable operating range in the overmodulation region. With this advanced overmodulation algorithm, the normal operating range can be extended without any extra hardware.

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.148-154
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• 2012

Purpose: In order to improve road-friendliness of heavy vehicles, a fuzzy hybrid control strategy consisting of a hybrid control strategy and a fuzzy logic control module is proposed. The performance of the proposed strategy should be effectively evaluated using a hardware-in-the-loop (HIL) simulation model of a semi-active suspension system based on the fuzzy hybrid control strategy prior to real vehicle implementations. Methods: A hardware-in-the-loop (HIL) simulation system was synthesized by utilizing a self-developed electronic control unit (ECU), a PCI-1711 multi-functional data acquisition board as well as the previously developed quarter-car simulation model. Road-friendliness of a semi-active suspension system controlled by the proposed control strategy was simulated via the HIL system using Dynamic Load Coefficient (DLC) and Dynamic Load Stress Factor (DLSF) criteria. Results: Compared to a passive suspension, a semi-active suspension system based on the fuzzy hybrid control strategy reduced the DLC and DLSF values. Conclusions: The proposed control strategy of semi-active suspension systems can be employed to improve road-friendliness of road vehicles.

• Journal of Korean Elementary Science Education
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• v.33 no.4
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• pp.710-723
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• 2014

The purpose of this study was to develop instructional strategy for newspaper-based science writing and to examine the effect of its application. The target unit was 'change of weather' and 'a variety of gas' in the sixth grade of elementary school, and the teaching strategy was composed of 3 stages-writing including realistic, interpretative and comprehensive writing. The result of applying this strategy into actual classrooms was as follows. First, it was proven that the science writing strategy using newspaper articles actually helped improving science process skills of learners, in particular, integrated process skills. Second, this strategy for science writing changed the scientific attitude of learners positively. While they read the newspaper articles, their thinking became more elaborate and systemized, which seemed to serve to foster their openness, criticism, and perseverance. Third, the science writing strategy did not contribute to the improvement of learners' science study achievement. To improve the understanding of scientific concepts and principles of learners, it is needed that teaching program combines with argument-based activity organically. The above-mentioned findings show that this instructional strategy using newspaper articles can be applicable as one of effective methods in science writing.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.332-338
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• 2021

Civil aviation cybersecurity challenges are global in nature and must be addressed using global best practices and the combined efforts of all stakeholders. This requires the development of comprehensive international strategies and detailed plans for their implementation, with appropriate resources. It is important to build such strategies on a common methodology that can be applied to civil aviation and other interrelated critical infrastructure sectors. The goal of the study was to determine the methodological basis for developing an international civil aviation cybersecurity strategy, taking into account existing experience in strategic planning at the level of international specialized organizations. The research was conducted using general scientific and theoretical research methods: observation, description, formalization, analysis, synthesis, generalization, explanation As a result of the study, it was established the specifics of the approach to formulating strategic goals in civil aviation cybersecurity programs in the documents of intergovernmental and international non-governmental organizations in the aviation sphere, generally based on a comprehensive vision of cybersecurity management. A comparative analysis of strategic priorities, objectives, and planned activities for their implementation revealed common characteristics based on a single methodological sense of cybersecurity as a symbiosis of five components: human capacity, processes, technologies, communications, and its regulatory support. It was found that additional branching and detailing of priority areas in the strategic documents of international civil aviation organizations (by the example of Cybersecurity Strategy and Cybersecurity Action Plan) does not always contribute to compliance with a unified methodological framework. It is argued that to develop an international civil aviation cybersecurity strategy, it is advisable to use the methodological basis of the Cyber Security Index.

• Korea Journal of Hospital Management
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• v.17 no.4
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• pp.87-115
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• 2012

This research classified hospital specialization strategy types through cluster analysis, analyzed fitness of hospital specialization strategy types for external environment or organizational structure, and examined relation between hospital specialization strategy types and organizational performance. This research surveyed 1,437 hospitals which have more than 30 patient's bed and practice national health service in Korea. Specifically, this research divided into two part : external fit - analysis of relation between external environment and specialization strategy, internal fit-analysis of relation between organizational structure factors and specialization strategy. also, as the organizational performance for achieving specialization strategic purpose, not only the productivity, efficiency, profit but also the medical quality was considered. In case of external fit, many hospitals chose integration type if there are a lot of competitive hospitals and regional population. Particularly, if there are many competitive hospitals, concentration type is chosen. In contrast, if there are many doctors in the region, differentiation type is chosen. In case of internal fit, according to organization type and patient's bed number, hospitals chose different types. If it is a general hospital and has a few bed number, generalization or concentration type is chosen. Tertiary hospital or the hospital with many patient's bed chose differentiation type. According to the number of specialists, if there are a few specialists, generalization or concentration type is chosen. If there are many specialists, differentiation type has high fitness for the hospital. In relation to strategy types and organizational performance, differentiation type has best result. Differentiation type has a good result in 7 items out of 11.

• Journal of the Korean School Mathematics Society
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• v.22 no.3
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• pp.277-302
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• 2019

In this study, we identified the effects of Self-Reflective Note(SRN) strategy, which used on 'college mathematics' courses, operated as a liberal arts curriculum course in university. For this purpose, we used SRN strategy on 'college mathematics' 3 classes, 'college mathematicsII' 1 class enrolled 95 students, and then analyzed the data. For identifying a change of students' learning, we conducted surveys related to the affective domain, core competencies, satisfaction. From this, we identified the followings. First, the interest, self-confidence, future expectation of students who attended classes in which SRN strategy is used are positively changed. Second, core competencies(self-directed ability, communication ability) of students who attended classes in which SRN strategy is used are improved. Third, the students who attended classes in which SRN strategy is used evaluated such as mathematics learning using the strategy help their mathematics study. Fourth, the students who attended classes in which SRN strategy is used evaluated such as the strategy improved their learning habit, supplemented their weakness, and activate realistic communication between professor and them.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.6
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• pp.1419-1428
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• 2013

This Study is to suggest marine tourism development strategy of Yeosu city using a A'WOT analysis technique. Main findings of this study are summarized as following. First, SO(strength-opportunity) strategy is considered as the most important strategy and followed by ST(strength-threat), WO(weakness-opportunity) and WT(weakness-threat) strategy. Second, it can be concluded that marine tourism facility and contents development is considered as the most important factor and followed by marine sport-related marine training program development and so on. For further research, more concrete and empirical study is to be performed by each strategy in the future.

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.73-79
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• 2011

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.83-92
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• 2023

The purpose of this study is to provide a rational management strategy to improve the management performance of companies through intellectual property activities. Through this study, we aim to explore countermeasures to strengthen competitiveness in a changing global environment. A survey of 200 companies was conducted from September 1 to October 30, 2023. Statistical analysis was conducted using frequency analysis, exploratory factor analysis, reliability analysis, correlation analysis, multiple regression analysis, and difference analysis. The conclusions are as follows. First, the impact of intellectual property activities on management performance was found to be creation and utilization. Second, the impact of management strategies on management performance was found to be differentiation strategy, cost advantage strategy, and concentration strategy. Third, cost advantage strategy has a partial mediation effect on the relationship between creation activities and managerial performance of intellectual property activities. Fourth, the differentiation strategy has a partial mediating effect on the relationship between the creation of intellectual property activities and managerial performance. In addition, differentiation strategy has a full mediating effect on the relationship between the utilization of intellectual property activities and performance. Fifth, concentration strategy has a partial mediating effect on the relationship between intellectual property activity utilization and management performance. Sixth, there is a difference between creation activities, protection activities, utilization activities, cost advantage strategy, differentiation strategy, financial performance, and non-financial performance based on venture certification status. As the importance of intellectual property is increasing in the era of technological hegemony, IoT companies will need to improve their management performance through venture certification and strategies utilizing intellectual property in order to secure future competitiveness. Based on this study, we hope that IoT companies will maximize their performance by implementing efficient strategies that consider IP activities.