• Title/Summary/Keyword: Balance Analysis

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Analytic study on thermal management operating conditions of balance of 100kW fuel cell power plant for a fuel cell electric vehicle (100kW급 연료전지 열관리 시스템 실도로 운전조건 해석적 연구)

  • Lee, Ho-Seong;Lee, Moo-Yeon;Cho, Choong-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.2
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    • pp.1-6
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    • 2019
  • The objective of this study was to investigate performance characteristics of thermal management system(TMS) in a fuel cell electric vehicle with 100kW Fuel Cell(FC) system. In order to build up analytic modelling for TMS, each component was installed and tested under various operating conditions, such as water pump, radiator, 3-Way valve, COD heater, and FC stack etc. and as the results of them, correlations reflecting component's characteristics with flow rate, air velocity were developed. Developed analytic modelling was carried out under various operating conditions on the road. To verify modelling's accuracy, after prediction for optimum coolant flow rate was fulfilled under certain operating conditions, such as FC system, water pump speed, opening of 3-way valve, and pipe resistance, analytic and experimental values were compared and good agreement was shown. In order to predict cold-start operating performance for analytic modelling, coolant temperature variation was analyzed with $-20^{\circ}C$ ambient temperature and duration was predicted to rise in optimum temperature for FC. Because there is appropriate temperature difference between inlet and outlet of FC stack to operate FC system properly, related analysis was performed with respect to power consumption for TMS and heat rejection rate and performance map was depicted along with FC operating conditions.

Effects of Game-based Postural Vertical Training on Pusher Behavior, Postural Control, and Activity of Daily Living in Patients With Acute Stroke: A Pilot Study (게임 기반의 자세수직 훈련이 급성 뇌졸중 환자의 밀기행동, 자세조절, 그리고 일상생활동작에 미치는 영향: 사전연구)

  • An, Chang-man;Roh, Jung-suk;Kim, Tack-hoon;Choi, Houng-sik;Choi, Kyu-hwan;Kim, Gyoung-mo
    • Physical Therapy Korea
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    • v.26 no.3
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    • pp.57-66
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    • 2019
  • Background: Visual and somatosensory integration processing is needed to reduce pusher behavior (PB) and improve postural control in hemiplegic patients with acute stroke. Objects: This study aimed to investigate the effects of game-based postural vertical training (GPVT) on PB, postural control, and activity daily living (ADL) in acute stroke patients. Methods: Fourteen participants with acute stroke (<2 months post-stroke) who had PB according to the Burke lateropulsion scale (BLS) (score>2) were randomly divided into the GPVT group ($n_1=7$) and conventional postural vertical training (CPVT) group ($n_2=7$). The GPVT group performed game-based postural vertical training using a whole-body tilt apparatus. while the CPVT group performed conventional postural vertical training to reduce PB (30 minutes/session, 2 times/day, 5 days/week for 3 consecutive weeks). The BLS was evaluated to assess the severity of PB. And each subject's postural control ability and ADL level were assessed using the postural assessment scale for stroke (PASS), balance posture ratio (BPR), and Korean-modified Barthel index (K-MBI). Outcomes were measured pre- and post-intervention. Results: Comparison of the pre- and post-intervention assessment results showed that both interventions led to the following significant changes: decreased severity of PB scores and increased PASS, BPR, and K-MBI scores (p<.05). In particular, statistical analysis between the two groups, the BLS score was significantly decreased in the GPVT group (p<.05). And PASS, BPR, and K-MBI scores were significantly improved in the GPVT group than in the CPVT group (p<.01, respectively). Conclusion: This study demonstrated that GPVT lessened PB severity and improved postural control ability and ADL levels in acute stroke patients.

A Biomechanics-Based Ergonomic Analysis for Footware Development (풋웨어 개발을 위한 생체역학 기반 인간공학적 분석 : B-boy 신발 개발을 중심으로)

  • Hah, Chong-Ku;Jang, Young-Kwan;Kim, Jin-Hyun
    • Journal of Convergence for Information Technology
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    • v.9 no.8
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    • pp.140-147
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    • 2019
  • The purpose of this study is to find biomechanical parameters for optimal shoes production through an ergonomic usability assessment of five existing types of shoes preferred by B-BOY. Ten experts and ten non-experts participated in the experiment, and 12 infrared cameras (Qualis, Oqus), force plate (Kistler, 9286AA) and foot pressure plate (Zebris Gmbh, Zebris PDM-System) were used to obtain the data. The results of the study are as follows. First, P shoes with a friction coefficient of 0.38 and a free moment of 0.32 N/m/kg are desirable in terms of traction capability and safety. Second, on the cushion, it was found that the N shoes 2.51 N, sec/kg and non-expert, and 2.86 N and sec/kg were suitable. Third, it is deemed appropriate for C shoes with a forefoot average pressure of 10.11 KPa (right), 10.05 KPa (left), and V shoes with a rearfoot average pressure of 8.4 KPa (right) and 8.36 KPa (left). In conclusion, the combination of the structure and material of V shoes should be developed for traction and stability, N shoes for cushion, and walking balance for C and V shoes.

Effects of Platform-based Exploratory and Exploitative Technology Strategy on Firm's Performance: Nanotechnology case (탐험과 활용관점 플랫폼 기술 포트폴리오 전략이 성과에 미치는 영향: 나노기술을 중심으로)

  • Moon, Hee-Sung;Shin, Juneseuk
    • Journal of Technology Innovation
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    • v.27 no.1
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    • pp.45-77
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    • 2019
  • The balance between exploration for new possibility and exploitation for existing certainty is an important issue in strategy, innovation, R&D as well as organization learning. Among the convergence trends of technologies, many firms seek to have the wider technological knowledge assets and the deeper technology capabilities for the sustainable competitive advantage at the same time. While firms plan technology portfolio strategies, they should consider the attribute of the technology. Nanotechnology, a cutting-edge technology, is a general purpose technology, unlike conventional product-oriented technologies. This empirical study was focused on how multi-national firms' exploration and exploitation strategies for nanotechnology affect their innovative and financial performance. It uses multiple regression analysis on panel data. This result shows that the more diversified and specialized nanotechnology as platform technology is positively related to their innovative and financial performance, unlike the research results for product-oriented technologies. In addition, exploratory innovation is more effective to firm performance than exploitation. This implies how global firms can manage effectively platform technology strategies under the constraints of resources.

Utilization of Work-Family Balance Support Policy and Factors Associated with Retention Intention among Married Female Officers with Preschool Children (미취학 자녀를 둔 기혼 여군 장교의 일·가정 양립 지원제도 활용 정도와 재직의도 영향요인)

  • Kwon, Jo Eun;Kim, Gwang Suk;Park, Jeongok;Kim, Sue
    • Women's Health Nursing
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    • v.25 no.3
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    • pp.329-344
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    • 2019
  • Purpose: This study aimed to identify utilization of the work-family support policy (WFSP) and factors affecting retention intention among Korean female military officers. Methods: This cross-sectional survey recruited 103 married female officers from the Korean Army, Navy, and Air force with preschool-aged children through convenience and snowball sampling. Via online surveys from June to November, 2018, the participants self-reported retention intention, work-family conflict, job satisfaction, and utilization of the WFSP. The data were analyzed using descriptive statistics, independent t-tests, one-way analysis of variance, Pearson's correlation coefficient, and multiple linear regression. Results: Retention intention ($22.29{\pm}5.98$) was reported at the mid-level, lower than scores reported in the literature for female workers. Work-family conflict ($32.51{\pm}5.29$) and job satisfaction ($63.10{\pm}7.45$) were above the midpoint levels. Use of maternity leave (100.0%) and parental leave (92.2%) was high, especially compared to the rates of child-care day off (20.4%) and parenting time (20.4%). 'Noticeable increases in childcare services within the army' (22.8%) was reported as the supportive measure needed the most by female military officers. Job satisfaction (${\beta}=.43$, $p{\leq}.001$), the use of parenting time (${\beta}=-0.29$, p=.002), living type (${\beta}=-.18$, p=.043), and service type (${\beta}=-.16$, p=.035) significantly influenced retention intention. Conclusions: The findings highlight the priority areas of importance within the WFSP and suggest that a family-friendly culture can improve female officers' retention intention. Accordingly, policy changes at the Ministry of National Defense improving the system to enhance a family-friendly culture in the military is expected to strengthen the retention intention of female officers and contribute to excellence in the military workforce.

Deep Learning Based Prediction Method of Long-term Photovoltaic Power Generation Using Meteorological and Seasonal Information (기후 및 계절정보를 이용한 딥러닝 기반의 장기간 태양광 발전량 예측 기법)

  • Lee, Donghun;Kim, Kwanho
    • The Journal of Society for e-Business Studies
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    • v.24 no.1
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    • pp.1-16
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    • 2019
  • Recently, since responding to meteorological changes depending on increasing greenhouse gas and electricity demand, the importance prediction of photovoltaic power (PV) is rapidly increasing. In particular, the prediction of PV power generation may help to determine a reasonable price of electricity, and solve the problem addressed such as a system stability and electricity production balance. However, since the dynamic changes of meteorological values such as solar radiation, cloudiness, and temperature, and seasonal changes, the accurate long-term PV power prediction is significantly challenging. Therefore, in this paper, we propose PV power prediction model based on deep learning that can be improved the PV power prediction performance by learning to use meteorological and seasonal information. We evaluate the performances using the proposed model compared to seasonal ARIMA (S-ARIMA) model, which is one of the typical time series methods, and ANN model, which is one hidden layer. As the experiment results using real-world dataset, the proposed model shows the best performance. It means that the proposed model shows positive impact on improving the PV power forecast performance.

A Study on Experience of Day Hospital and Day Care Service Use of The Mothers with Severely Disabled Children (중증장애아동 어머니의 낮병원 및 보육서비스 이용 경험에 관한 연구)

  • Jeon, Ji Hye;Won, Young Mi
    • Korean Journal of Child Education & Care
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    • v.19 no.1
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    • pp.159-174
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    • 2019
  • Objective: The study wanted to find out what changes the mother, who is the main parent of the severely disabled children, experienced in their lives through the use of day hospitals and child care services, and what difficulties they had, and discussed policy practical improvements that could satisfy both the medical and developmental needs of the severely disabled. Methods: The participants of the study were 9 mothers of a child with severe disabilities who had experience using hospitals and kindergarten. They were recruited by snowball sampling method. Focus group interview and individual interview were conducted. Results: As a result of the analysis, the mother of severely handicapped child gradually began to seek the balance of life as her child grew and became aware of the institution other than the day hospital. - (e.g) Although I was distracted and worried for the first time, I was gradually adjusting to the time away from my child thinking positively. Children with severe disabilities were also positively influenced by various experiences. They become to show som positive behavior or feeling such as brightening facial expressions or smile as they were using daycare centers or kindergartens in addition to daytime hospitals. Conclusion/Implications: Through the results of this study, comprehensive policy proposals on child care, welfare, and medical care were discussed.

Association Study of NDFIP2 Genetic Polymorphism with Asthma in the Korean Population (한국인에서 NDFIP2 유전적 다형성과 천식의 상관 연구)

  • Choi, Eun Hye;Hwang, Dahyun
    • Korean Journal of Clinical Laboratory Science
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    • v.53 no.3
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    • pp.249-256
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    • 2021
  • Asthma is a chronic inflammatory airway disease. There are many factors including genetic and environmental factors that influence asthma. The mitogen-activated protein kinase (MAPK) pathway is involved in maintaining the T helper cells 1 and 2 (Th1/Th2) balance and plays an important role in the development of asthma. In this study, the correlation between the NDFIP2 gene that regulates the MAPK pathway and asthma was analyzed. The genetic polymorphism of the NDFIP2 gene was analyzed between 193 asthma patients and 3,228 healthy controls in Korea. As a result, 4 single nucleotide polymorphisms (SNPs) showed a significant correlation (P<0.05) and high relative risk with asthma. Among them, rs2783122 of NDFIP2 showed a statistically significant association with asthma (P-value=9.76×10-6, odds ratio (OR)=1.67, 95% confidence interval (CI)=1.33~2.10). In the SNP imputation on the NDFIP2, 16 SNPs were discovered, and all of them showed significant correlation with asthma and high odds ratio. The genotype-based mRNA expression analysis revealed that the group of minor alleles of rs1408049 showed increased mRNA expression. Increased NDFIP2 expression causes the activation of the MAPK pathway, and this may influence the development of asthma. In conclusion, the polymorphisms of NDFIP2 are associated with asthma development and this can provide the basis for new guidelines for the management of asthma in the Korean population.

A Study on the ILS Development & PLS Method for SI Weapon System based Commercial Items (상용품 기반 SI 무기체계의 효과적 ILS 개발 및 후속군수지원 방안)

  • Jeong, Inn-Sung;Lee, Yu-Se
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.417-425
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    • 2020
  • Recently, the development of weapons systems in conjunction with the Fourth Industrial Revolution has increased the number of weapon systems that integrate individual commercial systems by actively incorporating the superior fields of private commercial technologies. In the case of such commercial product-based weapons systems, however, the development of ILS elements across all areas, such as technical manual, military field maintenance support equipment, interactive electronic technical manual (IETM), and Computer Based Training (CBT) development, and weapons system Reliability, Availability, Maintainability(RAM) target values, and logistics support analysis (LSA) was requested to expand the level of development by developers. The commercial product-based System Integration (SI) weapon system will be able to complete the comprehensive military balance for complementing and effective maintenance of the military and developers only when the ILS development, which is limited to the essential elements of the required group, Request For Proposal (RFP) and Post-Logistics Support (PLS) directions were applied in the framework of outsourcing maintenance implementation. As a result, by checking the operation status of current weapons systems, the logistics support of commercial product-based weapon systems selected outsourcing as the basic policy that is decided based on the development requirements, focusing on maintaining operation through a rational decision-making process, and presented a plan for applying the development plan to the RFP for the determined core elements and PLS.

A Study on Collective Self-esteem of Public Librarian Servant and Supporting Factors in their Work Environment (공무원사서의 집단자존감과 직무환경 지원 요인에 관한 연구)

  • Lee, Ja-Young;Hong, Hyun-Jin
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.32 no.1
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    • pp.295-314
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    • 2021
  • The purpose of this study is to find out the factors that affect the 'public librarian servant's' Collective Self-Esteem (CSE) in Korean relation-oriented collectivism. The research was organized into a research model by setting up a hypothesis on the impact relationship the between the group Collective self-esteem, the work environment factors and cognition of Superior institution of the Public librarian servant. The relevant data collection was conducted for public librarian servant working in public libraries nationwide through the method of survey. From April 3, 2020 to May 14, 2020, it was conducted for Public Librarian Servant in public libraries nationwide with Civil Service System, Office of Education, Ministry of Culture·Sports and Tourism based on responses for 301 Public Librarian Servant from 559 institution. According to the analysis, the cognition of the superior institution of Public Librarian Servant influences the cognition of Collective Self-Esteem among the sub-factors of Collective - Self - Esteem of Collective Self-Esteem. This study is meaningful in that 'Public Librarian Servant' who was treated as an individual entity in the study of Library and Information Science study, as being has relationship with various groups and is dealt with multi-dimensionally in Korean relation-oriented collectivism culture. Research suggests that when Public Librarian Servant exist as one of the subordinate organizations to vast Civil service system, it suggest that Public Librarian Servants should find out a balance for improve their relatively low social values.