• 대한통합의학회지
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• 제6권2호
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• pp.69-76
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• 2018

Purpose : This study investigated the effects of low-intensity muscle training on neurotransmitters associated with depression and emotion regulation disorders in survivors with stroke who were diagnosed with depression or emotion regulation disorder. Methods : Survivors of chronic stroke diagnosed with depression or emotion regulation disorder (n = ) were included in the study. Concentrations of serotonin, norepinephrine, and epinephrine were measured before and after. Low-intensity muscle training was performed once a day for 50 minutes, 5 times a week for 10 weeks. Result : Levels of serotonin, norepinephrine, and epinephrine improved significantly after intervention (p < .05). Conclusion : These results confirm that low-intensity muscle training has a positive effect on neurotransmitter concentrations in survivors with stroke diagnosed with depression and emotion regulation disorders. Future studies should analyze the changes in neurotransmitters in more detail using various exercise methods and intensities to investigate their effects on depression and emotion regulation disorders.

• 복식문화연구
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• 제26권2호
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• pp.251-263
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• 2018

As mobile shopping has increased in the new media age, fashion consumers' decision making and product consumption processes have changed. The volume of consumer-driven information has expanded since media and social networking sites have enabled consumers to share information they obtain. The purpose of this study was to determine the factors affecting information searching strategies and information sharing about fashion products. An online survey collected data from 466 respondents, relating to the influence of product price level and consumer SNS commitment level on information search and information sharing. Experimental design of three product price level and two consumer SNS commitment level was used. Analysis of the data identified factors in fashion information searching as ongoing searching, prepurchase web portal information search, and prepurchase marketing information search. For low-price fashion products, prepurchase product-detail influenced intention to share information. For mid-priced products, ongoing search significantly affected intention to share information. Both ongoing search and prepurchase marketing information search showed significant effects for high-price products. Consumers who are more committed to SNS engaged in significantly more searching in all aspects of information search factors. Significant interaction effect was detected for consumer SNS commitment level and product price level. When consumers with low consumer SNS commitment search for information on lower-priced fashion products, they are less likely do a prepurchase web portal information search.

• 한국유체기계학회 논문집
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• 제18권1호
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• pp.11-19
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• 2015

Recently, the cross flow turbines attract more attention for their good performance over a large operating regime at off design point. This study employs a very low head cross flow turbine, which has open inlet duct and has barely been studied before, to investigate the performance of the cross flow turbine with air suction from the rear part of the runner. Unlike conventional cross flow turbines, a draft tube is attached to the outlet of runner to improve the turbine performance. Water level and pressure in the draft tube are monitored to investigate the influence of air suction. Torque at local blade passage of three parts of runner is examined in detail under the conditions of different air suction. Consequently, it is found that with proper air suction in the runner chamber, the water level in the draft tube gradually drops to Stage 2 of the runner and the efficiency of the turbine can be raised by 10%. Overall, the effect of air-layer on the performance of the turbine is considerable.

• 수산경영론집
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• 제48권1호
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• pp.1-16
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• 2017

The fisheries industry has led the Korean economy, and has been achieving high-level position in the world. However, this industry meets aging, low growth and profit. In order to overcome this critical situation, it is needed to understand the overall status of industry. In industry level, most of previous researches focused on ocean industry rather than fisheries. In addition, scholars have been getting a lot of attention about fisheries cooperatives, fishing-ports, methods of fishery, and manufacturing process in fisheries sector. The aim of this research is analysis of domestic fisheries industry's managerial performance using data envelopment analysis(DEA) considering operating and scale view. Furthermore, the comparative analysis is performed by firm size, and industry type. In results, fisheries industry's managerial performance is not high, overall. In more detail, most of big size firms are under decreasing returns to scale(DRS) status. Fishery processing industry's performance is low, and fishery distribution industry has the best performance. This paper suggests that transferring operating capability from big firms to small firms, and policy supports and firm's activities should be accompanied for high-value added in fisher, and fishery processing industries.

• IEIE Transactions on Smart Processing and Computing
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• 제3권2호
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• pp.41-51
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• 2014

This paper describes a method to estimate the noise power using the minimum statistics approach, which was originally proposed for audio processing. The proposed minimum statistics-based method separates a noisy image into multiple frequency bands using the three-level discrete wavelet transform. By assuming that the output of the high-pass filter contains both signal detail and noise, the proposed algorithm extracts the region of pure noise from the high frequency band using an appropriate threshold. The region of pure noise, which is free from the signal detail part and the DC component, is well suited for minimum statistics condition, where the noise power can be extracted easily. The proposed algorithm reduces the computational load significantly through the use of a simple processing architecture without iteration with an estimation accuracy greater than 90% for strong noise at 0 to 40dB SNR of the input image. Furthermore, the well restored image can be obtained using the estimated noise power information in parametric image restoration algorithms, such as the classical parametric Wiener or ForWaRD image restoration filters. The experimental results show that the proposed algorithm can estimate the noise power accurately, and is particularly suitable for fast, low-cost image restoration or enhancement applications.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.195-201
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• 2008

In the jet engines on the aircrafts cruising at high altitude over 20 km and subsonic speed, the Reynolds number in terms of the compressor blades becomes very low. In such an operating condition with low Reynolds number, it is widely reported that total pressure loss of the air flow through the compressor cascades increases dramatically due to separation of the boundary layer and the secondary-flow. But the detail of flow mechanisms causes the total pressure loss has not been fully understood yet. In the present study, two series of numerical investigations were conducted to study the effects of Reynolds number on the aerodynamic characteristics of compressor cascades. At first, the incompressible flow fields in the two-dimensional compressor cascade composed of C4 airfoils were numerically simulated with various values of Reynolds number. Compared with the corresponding experimental data, the numerically estimated trend of total pressure loss as a function of Reynolds number showed good agreement with that of experiment. From the visualized numerical results, the thickness of boundary layer and wake were found to increase with the decrease of Reynolds number. Especially at very low Reynolds number, the separation of boundary layer and vortex shedding were observed. The other series, as the preparatory investigation, the flow fields in the transonic compressor, NASA Rotor 37, were simulated under the several conditions, which corresponded to the operation at sea level static and at 10 km of altitude with low density and temperature. It was found that, in the case of operation at high altitude, the separation region on the blade surface became lager, and that the radial and reverse flow around the trailing edge become stronger than those under sea level static condition.

• Journal of Information Technology Applications and Management
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• 제17권2호
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• pp.19-45
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• 2010

This research has analyzed the differentiated influence of organizational variables(an organization's learning culture and organizational support networks) and personal variables(the individual's motivation to learn and self-efficacy) on the process of gaining and using of knowledge. These two variables have been regarded as the major variables for the successful learning of 6Sigma, according to Social Cognitive Theory. In addition, this research has proven the role structure of the abovementioned two variables through a suitable methodology(Hierarchical Linear Model). In regard to this methodology, the different hierarchical level of the personal variable and organizational variable was especially focused on, and the effect of interaction between the high level and the low level was considered in detail. Considering the current situation, in that the importance of organizational factor and personal factor has been emphasized but the accurate role of each variable has not been verified, the research model is thought to help to establish an effective strategy to implement 6 Sigma.

• Journal of Power Electronics
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• 제13권5호
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• pp.909-918
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• 2013

This paper proposes a coordinated control of the reactive power between the STATCOMs (static synchronous compensators) and the grid-side converters (GSC) of wind farms equipped with PMSGs (permanent-magnet synchronous generators), by which the voltage fluctuations at the PCC (point of common coupling) are mitigated in the steady state. In addition, the level of voltage sags is reduced during grid faults. To do this, the GSC and the STATCOM supply reactive power to the grid coordinately, where the GSCs are fully utilized to provide the reactive power for the grid prior to the STATCOM operation. For this, the GSC capability of delivering active and reactive power under variable wind speed conditions is analyzed in detail. In addition, the PCC voltage regulation of the power systems integrated with large wind farms are analyzed for short-term and long-term operations. With this coordinated control scheme, the low power capacity of STATCOMs can be used to achieve the low-voltage ride-through (LVRT) capability of the wind farms during grid faults. The effectiveness of the proposed strategy has been verified by PSCAD/EMTDC simulation results.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제31권1호
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• pp.103-123
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• 2017

수학 수업에서 교사가 학생들이 제시할 적절한 과제를 선정하는 것은 중요하며 다양한 유형의 수학적 과제를 수반하는 수학 교과서의 효율적인 활용 또한 유의미하다고 할 수 있다(NCTM, 2000). 이러한 맥락에서 수학적 과제와 관련하여 이를 수반하는 수학 교과서의 탐색 및 분석은 의미 있는 일이며, 이때 수학적 과제들을 중심으로 구현된 MiC 교과서의 탐색이 적절할 것으로 판단된다. 그리하여 본 연구에서는 MiC 교과서에서 다루고 있는 수학적 과제들을 대상으로 학생들이 다양한 유형의 수학적 과제들을 통해 겪게 되는 인지적 요구 수준에 대해 살펴보고자 하였다. 본 연구에서는 2006년에 출판된 MiC 교과서를 대상으로 하되, MiC 교과서의 모든 내용을 다루기에는 방대하므로 학교 안팎의 실생활 소재나 문제 상황이 보다 풍부한 '자료 분석과 확률' 영역을 선정하여 중학교급에 한정하여 다루기로 하였다. 한 마디로, 본 연구에서는 Stein 외(2009)가 제안한 과제 유형별 특징, 즉 '인지적 요구 수준(cognitive demand level)'을 기반으로 과제 유형 분석틀을 재구성하여 마련하고, 이를 토대로 MiC 교과서에서 다루고 있는 총 22개의 수학적 과제들의 수준(유형)을 살펴보고자 하였다. 끝으로, 본 연구 목적에 따라 도출된 양질의 결과를 토대로 교수 학습 자료의 개발 및 활용을 위한 제언을 덧붙이고자 한다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.513-521
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• 2017

HVDC protection setting is difficult to be calculated analytically because of its strong nonlinearity. The currently used setting method is based on the empirical setting of previous projects and then verified by digital simulation. It entails a huge workload and low efficiency. To facilitate protection setting, this paper systematically summarizes the HVDC protection characteristics and then presents a classification of HVDC protections according to the protection principles. On the basis of the fault quantities, a novel setting procedure suitable for travelling wave protection, derivative and level protection, and differential protection is proposed. The proposed procedure is illustrated and verified in detail with the example of travelling wave protection. An HVDC protection setting system that has the functions of automatic protection setting and data management is developed utilizing the C# programming language.