• Journal of Power System Engineering
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• v.18 no.5
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• pp.129-136
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• 2014

This paper proposes improvement on sensorless vector control performance of a permanent magnet synchronous motor (PMSM) with sliding mode observer. An adaptive observer gain and second order cascade low-pass filter (LPF) were used to improve the estimation accuracy of the rotor position and speed. The adaptive observer gain was applied to suppress the chattering intensity and obtained by using the Lyapunov's stability criterion. The second order cascade LPF was designed for the system to escalate the filtering performance of the back-emf estimation. Furthermore, genetic algorithm was used to optimize the system PI controller's performance. Simulation results showed the effectiveness of the suggested improvement strategy. Moreover, the strategy was useful for the sensorless vector control of PMSM to operate on the low-speed area.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.192-201
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• 1997

The feedback control scheme of the pressure control system of the rear wheel steering gear which has relatively large volume and sprung load was built up in order to improve th response characteristic of the system. The control algorithm chosen was a feedback compensator joined by a feedfoward compensator and the model matching method was used in the process of control system design. The structures and properties of the reference models were inspected and the parameters of the controller were decided. The improvement of the response characteristic of the pressure control valve by means of the feedback control is affirmed. Particularly, when the order of the system model is higher than the 2nd order, the effectiveness of the feedback control on the improvement of the response characteristic of the valve is distinct. And the convenience of the model matching method is the process of control system design is confirmed as well.

• ETRI Journal
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• v.34 no.2
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• pp.184-189
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• 2012

In this paper, we propose a novel approach to statistical model-based voice activity detection (VAD) that incorporates a second-order conditional maximum a posteriori (CMAP) criterion. As a technical improvement for the first-order CMAP criterion in [1], we consider both the current observation and the voice activity decision in the previous two frames to take full consideration of the interframe correlation of voice activity. This is clearly different from the previous approach [1] in that we employ the voice activity decisions in the second-order (previous two frames) CMAP, which has quadruple thresholds with an additional degree of freedom, rather than the first-order (previous single frame). Also, a soft-decision scheme is incorporated, resulting in time-varying thresholds for further performance improvement. Experimental results show that the proposed algorithm outperforms the conventional CMAP-based VAD technique under various experimental conditions.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.79-86
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• 2013

Demand of new suburban residential development and a variety of new types for housing have intensified by urban Citizens overused of poor urban residential environment. Income growth and improvement of living standards for the quality of the living environment are increasing demands of creating a more comfortable living environment. Thus, according to changes in social conditions, the development of urban area while accommodating additional development pressure adequately, particularly residential development in order to promote the efficient development of suburban areas are planned for the rational development direction. This study suggests the following improvement measures by analyzing the characteristics of the Suburban Housing Complexes built recently. In order to create a more pleasant Suburban Housing Complexes First, the accessibility of the traffic conditions, education and public facilities is good Second, the construction plans reflected needs of the consumers should be made Third, necessary facilities for activation of the urban-rural exchanges must be equipped.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.18 no.1
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• pp.58-65
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• 2007

Objectives : Motivational factor is a unique contributor to the typically poor academic performance of children with ADHD. However, few study has directly intervened learning motivation in children with ADHD. We conducted this study to explore the direct effects of the learning motivation improvement program applied to children with ADHD. Method The program was designed in order to increase an interest-inducing educational intervention, an academic skills integration, a basic learning activity (reading, writing, and math), and children's self-esteem. We conducted the program twice a week (total 10 sessions) and assessed learning motivation, teaming attitude, self-esteem, academic performance, and problem behaviors of participating children. Results : After the program, teachers reported improvement in teaming motivation. In addition, parents notified sisnificant reduction of problem behaviors. Children reported improvement in a few domains of teaming motivation and learning attitude. Conclusion : While loaming motivation is regarded as an important factor in education, there have been few studies considering this issue in both educational and psychiatric fields. The teaming motivation improvement would be needed in both field in order to reduce the deficits in academic performance in children with ADHD.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.1
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• pp.59-70
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• 2010

This paper reorganized five service qualities dimensions of ski-resorts, then derived the improvement priority order of the service quality through a satisfaction measure considering the importance. There're more competitive situations to guarantee customers using the skies and snowboards is a major sports in winter season. In these competitive environments, this paper's going to propose a predominant-competitive strategies for improving the service quality of ski-resorts. This study measured the satisfaction considering the importance of service quality target on customers has an experience ski resort service quality to improve ski resort service quality. This study using Performance Model decide a priority order about a particular item improvement, then is going to present a guideline that can improve the service quality more exactly. As a result of the study the factors that is important to the customer were prime physical factor, access, assistance physical factor, staff service and assistant service, an improvement priority order were accommodation and eating-drinking facilities, waiting time of a slope and lift/gondola, entertainment/shopping facilities in the resorts, equipment rental and lift fare.

• IE interfaces
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• v.17 no.4
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• pp.450-458
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• 2004

S-Distribution Center supplies parts to three plants of K-automobile manufacturing company. Since the three plants employ the JIT production system, it is important for S-Distribution Center to deliver small quantities of parts frequently and quickly on time. This paper presents a case study on the improvement of order-picking operation in S-Distribution Center. The study is focused on the reductions of move time and waiting time by redesigning the parts storage location, picking-order terminal location, retrieval policy, and equipment operation policy. The proposed operation system for S-Distribution Center is evaluated through a simple computation analysis and computer simulation. Furthermore, the reducible numbers of equipment and order pickers are investigated by performing a sensitivity analysis.

• Journal of the military operations research society of Korea
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• v.28 no.2
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• pp.1-19
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• 2002

This study shows the effect of inventory policy change from supplier-based to customer-based. We focus on the service level, cost, and information distortion of the Military Supply Chain(MSC) with System Dynamics. We design MSC model according to field practician interviews by using Vensim. The simulation makes a comparison between supply-based inventory policy performances and order-based inventory policy performances. In order to evaluate the MSC performances, we measure the accumulation of backlog(service level), supply chain cost, and order percentage overshoot(information distortion). The results show that 1) changing inventory policy from supplier-based to end customer order-based gets a good customer service, reduces MSC cost, and prevents information distortion, 2) changing inventory policy from supplier-based to immediate customer order-based reduces a small amount of MSC cost and deteriorates customer service, and 3) supply level is main factor for MSC performances improvement. This study implicates the policy change makes a improvement of MSC performance without introducing information system.

• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.91-100
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• 2018

This study aims to identify more reasonable and efficient development plans to engage local university students in landscape improvement projects in rural areas. To survey university students, residents, administrators and experts involved in such projects on important considerations in this regard, SWOT analysis was employed to identify important factors, followed by analytic hierarchy process (AHP) to evaluate their relative importance, identify problems and suggest implications for improvement. The results are summarized as follows: the relative importance of the SWOT group was in the order of opportunity, strength, threat, and weakness. For each SWOT factor, the relative importance of strengths was in the order of students' aspiration and passion, availability of creative ideas and designs, and improved attachment to their community. The relative importance of weaknesses was in the order of the lack of spontaneous participation of residents, short preparation periods and insufficient budgets, and the lack of experience in similar projects. The relative importance of opportunities was in the order of young students' activity itself being a boost factor to the community, students' endeavors arising a consensus among residents, and students feeling a sense of duty as representatives of their school. The relative importance of threats was in the order of projects being one-shot, temporary events, immaturity, and differences in preferences between older and younger generations. To draw an overall ranking of the sub-factors evaluated, the overall relative importance of the decision-making factors was evaluated. Among the sub-factors for each SWOT group, young students' activity itself being a boost factor to the community as an opportunity factor was shown to be the most important, while the lack of experience in similar projects was shown to be the least important as administrators and experts made appropriate interventions in each stage.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1636-1641
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• 2018

The purpose of this study was to investigate the relationship between the needs for environmental improvement and dementia patients' activity of daily living (ADL) and behavior and psychological symptoms of dementia (BPSD) in dementia patients living in urban type dementia care villages. The subjects of this study were 70 households with cognitive impairment and dementia among residents of dementia care village in Gunsan City. The survey was conducted with the permission of their family. Frequency analysis and descriptive statistical analysis were performed on the main variables to analyze the characteristics of the subjects. Bivariate correlation analysis was performed to verify the relationship between the two variables. According to the analysis results, the order of environment improvement was in the order of entrance (51.4%), toilet and stairs (48.6%), kitchen (11.4%), bedroom and laundry room (10.0%). In the relationship between the variables, The ADL was correlated with age (r=.315, p <.01), BPSD (r=.322, p<.01) and living environment inconvenience (r=.640, p<.01) while, living environment inconvenience correlated with environment improvement need (r=.669, p<.01). This study suggests that improvement of the residential environment of dwellers in dementia care villages, especially the stairway and entrance hall is necessary.