• Title/Summary/Keyword: switching strategy

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Development of DC/DC Converters and Actual Vehicle Simulation Experiment for 150 kW Class Fuel-cell Electric Vehicle (150kW급 수소연료전지 차량용 DC/DC 컨버터 개발 및 실차모사 실험)

  • Kim, Sun-Ju;Jeong, Hyeonju;Choi, Sewan;Cho, Jun-Ho;Jeon, Yujong;Park, Jun-Sung;Yoon, Hye-Sung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.1
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    • pp.26-32
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    • 2022
  • This paper proposes a power system that includes a 120k W fuel cell DC-DC converter (FDC) and 30 kW bidirectional DC-DC converter (BHDC) for a 150 kW fuel-cell vehicle. With a high DC link voltage of 800 V, the efficiency and power density of the power electronic components are improved. Through the modular design of FDC and BHDC, electric components are shared, resulting in reduced mass production costs. The switching frequency of 30 kHz of full SiC devices and optimal design of coupled inductor reduce the volume, achieving a power density of 8.3 kW/L. Furthermore, a synergetic operation strategy using variable limiter control of FDC and BHDC was proposed to efficiently operate the fuel cell vehicle considering the fuel cell stack efficiency according to the load. Finally, the performance of the prototype was verified by Highway Fuel Economy Driving Schedule testing, EMI test, and the linked operation between FDC and BHDC. The full load efficiencies of the FDC and BHDC prototypes are 98.47% and 98.74%, respectively.

Infantile Colic: A Survey of Physicians in Pakistan

  • Muhammad Saif Jalal;Syed Zafar Mehdi;Jalal Uddin Akber;Murtaza Ali Gowa;Carlos Lifschitz
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.27 no.3
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    • pp.186-195
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    • 2024
  • Purpose: Infantile colic diagnostic criteria were established by Rome IV. A universally accepted management remains to be established. We aimed to evaluate diagnostic criteria, management strategies, and perceived regional prevalence of infantile colic in Pakistan, as well as its effect on physicians and parents. Methods: A questionnaire was distributed amongst 1,256 physicians. Results: We received 800 replies. Wessel and Rome IV criteria were used by most physicians for diagnosis; however, the response "any infant who cries a lot" was selected by older physicians (48% of those over 60 years), physicians in rural areas (32%), physicians practicing in private clinics (27%), and general physicians (30%). Estimated prevalence of infantile colic ranges from 21-40%. Reassurance was the most widely recommended management strategy followed by herbal teas (51%), switching to a different formula (49%), probiotics (28%) and antibiotics (26%), discontinuation of breastfeeding (14%), elimination of dairy products from the breastfeeding mothers' diet (6%), and the administration of colic drops (1%). Most physicians considered the negative impact of colic on their personal lives and the parents as mild-to-moderate. Notably, 38% of percent of physicians routinely screened for maternal depression, and 45% of physicians were aware of the association between infantile colic and shaken baby syndrome. Conclusion: Most physicians in Pakistan diagnose and manage infantile colic according to the established guidelines. However, the guidelines pertaining to treatment planning are not followed. Educational efforts directed toward general physicians and doctors practicing in rural areas and clinics must be implemented to avoid unnecessary testing and treatment burden.

Beyond Medical Bills: High Prevalence of Financial Toxicity and Diverse Management Strategies Among Vietnamese Patients With Cancer

  • Binh Thang Tran;Thanh Gia Nguyen;Dinh Duong Le;Minh Tu Nguyen;Nhan P. T. Nguyen;Minh Hanh Nguyen;The Due Ong
    • Journal of Preventive Medicine and Public Health
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    • v.57 no.4
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    • pp.407-419
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    • 2024
  • Objectives: This study was conducted to measure financial toxicity (FT) among patients with cancer in Vietnam using the COmprehensive Score for financial Toxicity (COST) and to describe the cost management strategies employed by these patients. Methods: This comprehensive cross-sectional study enrolled 634 patients from 2 specialized oncology hospitals in Vietnam. Using COST cut-off scores, FT was classified as none/mild (≥26), moderate (14-25), or severe (≤13). Cost management strategies, or coping mechanisms, were classified into 4 groups: lifestyle changes, financial resource strategies, treatment modifications, and support seeking. Results: The prevalence of FT was 91.8%, with 51.7% of participants demonstrating severe and 40.1% exhibiting moderate FT. Severe FT was significantly associated with female, low education level, unstable employment, low household economic status, and advanced cancer stage. The most common coping strategies were as follows: among lifestyle changes, reducing spending on basic items and leisure activities (78.7%) and cutting back on essential household expenses (66.4%); among financial resource strategies, borrowing money from relatives or friends (49.1%) and withdrawing funds from retirement or savings accounts (34.1%); within treatment modifications, switching treatment facilities or doctors due to cost concerns (9.3%); and within support seeking, obtaining help from welfare or community organizations (18.8%). All strategies were significantly more likely to be used by patients with severe FT. Conclusions: FT was highly prevalent among patients with cancer. Most patients relied on lifestyle adjustments and coping strategies, underscoring the need for improved financial support systems to alleviate the economic burden associated with cancer care.

The Influence of Webtoon Usage Motivation and Theory of Planned Behavior on Intentions to Use Webtoon: Comparison between movie viewing, switching to paid content, and intention for buying character products (웹툰 이용동기와 계획행동이론 변인이 웹툰 관련 행동의도에 미치는 영향: 영화관람, 유료 콘텐츠 전환시 이용, 캐릭터 상품 구매의도의 비교)

  • Lee, Jeong Ki;Lee, You Jin;Kim, Byung Gue;Kim, Bo Mi;Choi, Sun Ryul;Koo, Ja Young;Koleva, Vanya Slavche
    • Korean Journal of Communication Studies
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    • v.22 no.2
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    • pp.89-121
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    • 2014
  • In order to suggest a strategy for continuous growth of webtoon, this article examined webtoon usage motivation and tried to make a prediction about culture content products and services connected with webtoon, including intention for viewing movies, based on webtoon; intention for switching to paid webtoon content, and intention for buying webtoon character products. From the point of view of Uses and Gratification Theory intentions for using webtoon and human sociocultural behavior intention are already predicted but with the usefulness of Theory of Planned Behavior Integrated Model this study extended the explanation power of prediction about webtoon related behavioral intention. Results found 5 motivational factors for webtoon usage i.e. 'seeking information', 'entertainment and access availability', 'webtoon genre characteristics', 'influence from a friend or acquaintance', and 'escapism and tension release'. Among them the ones that influenced the intention for viewing movies, based on webtoon, were found to be 'webtoon genre characteristics', 'escapism and tension release' and the 3 variables from Theory of Planned Behavior. 'Seeking information', 'entertainment and access availability', 'webtoon genre characteristics', and all the 3 variables from Theory of Planned Behavior were found to influence the intention for switching to paid webtoon content. The intention for buying webtoon based character products was affected by the motivational factors 'seeking information', 'escapism and tension release' and the behavior and subjective norms variables from Theory of Planned Behavior. Based on the uncommon results from the research several suggestions were made for the continuous growth of webtoon.

A Study of Production Technology of Digital Contents upon the Platform Integration : Focusing on Cross - Platform Game (플랫폼 통합에 따른 디지털콘텐츠 제작기술 경향연구 : 크로스 플랫폼게임(Cross-Platform Game) 사례를 중심으로)

  • Han, Chang-Wan
    • Cartoon and Animation Studies
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    • s.14
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    • pp.151-164
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    • 2008
  • Cross platform game has brought about the expansion of game market, which results in technology innovation overcoming the limit of game consumption. The new model integrates both off and online game services. Gamers can now enjoy game service regardless of age, time, and space. If the technology evolution model of digital contents like cross-platform game engine can provide contents for several platform at the same time, the interactive service can be utilized into maximum level. It is also necessary to allocate, switch data as well as to innovate the transmission technology of data according to each platform. Providing the same contents for several platform as many as possible can be the most suitable strategy to enhance the efficiency and profits. However if the interactive service can be accomplished completely, the development of data switching technology and distribution should be made. To be a leader in the next digital contents market, one should develop the network engine technology which can embody the optimization of consumption in the interactive network service.

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A Three-phase Current-fed DC-DC Converter with Active Clamp (연료전지용 3상 전류형 능동클램프 DC-DC 컨버터)

  • Cha, Han-Ju;Choi, Jung-Wan;Yoon, Gi-Gab
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.6
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    • pp.456-464
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    • 2007
  • This paper proposes a novel three-phase current-fed active clamp DC-DC converter for fuel cells. A single common active clamp branch is used to limit transient voltage across the three-phase full bridge and to realize zero-voltage switching(ZVS) in all switches. To apply for the power generation system current-fed type has been combined with the three-phase power conversion system. The proposed approach has the following advantages: an increase (by a factor of three) of input current and output voltage chopping frequencies; lower RMS current through the inverter switches with higher power transfer capability; reduction in size of reactive later components and the power conditioning system; better transformer utilization; increase of the system reliability. Therefore, the proposed three-phase current-fed active clamp DC-DC converter is appropriate for the boost type DC-DC converter for fuel cells and also applicable for the photovoltaic and battery charge system. The paper details the analysis, simulation and hardware implementation of the proposed system. Finally, experimental results with the proposed PWM strategy demonstrate the feasibility of the proposed scheme on a 500W prototype converter.

Omnichannel's Perception Effect on Omnichannel Use and Customer-Brand Relationship (옴니채널의 지각된 편리성과 유용성이 옴니채널 사용과 소비자-브랜드 관계에 미치는 영향)

  • Yim, Duk-Soon;Han, Sang-Seol
    • Journal of Distribution Science
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    • v.14 no.7
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    • pp.83-90
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    • 2016
  • Purpose - This study focuses on new type distribution channel that named as Omnichannel. Omnichannel is developed from Multichannel which is used in many distribution channels to buy or selling goods. Omnichannel basically needs an Information and Communications Technologies(ICT) to use, so researcher conduct a Technology Acceptance Model(TAM) to research model. Customer-brand relationship was used as dependent variable to focus on the role of Omnichannel. Research design, data, and methodology - The subject of this study is customer who purchase goods or service through omnichannel. Based on the literature from the preceding research analysis of TAM and customer-brand relationship, this study was constructed by the reference to previous studies, final research model design for figure out casual relationship among perceived ease of use, perceived usefulness, omnichannel use and customer-brand relationship. From 2016 February 3 to March 17, questionnaire survey targeted customers who use online and offline channels. 273 questionnaire survey had conducted, then, 252 survey data were available for empirical analysis. Researcher provide descriptive statistics for checking generality. Cronbach's alpha value was used to check the reliability of data. Exploratory factor analysis was used for purification of values and eigenvalue checking. After EFA, Confirmatory factor analysis was used to prepare structural equation modeling with executing structural equation modeling for confirming hypothesis which developed by researcher. Results - The main results of this empirical study are as follows. First, omnichannel's perceived ease of use has positive significant effect on perceived usefulness(estimate: 0.579). Moreover, omnichannel's perceived ease of use and perceived usefulness has positive significant effect on omnichannel use(estimate: 0.325,0.648). Second, using omnichannel has positive significant effect on brand-customer relationship(estimate: 0.521). Every hypothesis adopted as researcher designed. This study found out the intermediate relationship between perceived ease of use and omnichannel use by investigating hypothesis. Conclusions - Base on the empirical result, this study confirmed that TAM theory perceived has relation with omnichannel. First, factors of TAM has positive effect on omnichannel use, so it highlights the important role of customer based interface and usefulness. Especially, perceived usefulness has high indirect influence on ease of use and use of omnichannel. It seems that when customers try to decide use or not use omnichannel, customers focus on percept benefits from omnichannel. Thus, a provider should applicate attractive price table, accurate product or service information and high switching cost strategy to emphasize the usefulness of omnichannel. Second, using omnichannel enhances the relationship between customers and brand, because there are more time and frequency to serve customers. It is important because good relationship between customers can increase the future's financial performance through word of mouse, positive brand image and loyalty to brand or company. Finally, despite of empirical result and implications, this study has limitations. First, there are only a few previous studies about omnicahnnel, so literature reviews are restricted. While set up the factors which can affect the use of omnichannel, next study should be considered with broader theories or models(ex: contingency theory). Second, omnichannel has developed from multichannel, so comparative analysis is needed between these methods because there is a possibility about different forte character of each distribution system on customer's consuming patterns.

On the Experimental Modeling of Focal Plane Compensation Device for Image Stabilization of Small Satellite (소형위성 광학탑재체의 영상안정화를 위한 초점면부 보정장치의 실험적 모델링에 관한 연구)

  • Kang, Myoung-Soo;Hwang, Jai-Hyuk;Bae, Jae-Sung;Park, Jean-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.8
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    • pp.757-764
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    • 2015
  • Mathematical modeling of focal plane compensation device in the small earth-observation satellite camera has been conducted experimently for compensation of micro-vibration disturbance. The PZT actuators are used as control actuators for compensation device. It is quite difficult to build up mathematical model because of hysteresis characteristic of PZT actuators. Therefore, the compensation device system is assumed as a $2^{nd}$ order linear system and modeled by using MATLAB System Identification Toolbox. It has been found that four linear models of compensation device are needed to meet 10% error in the input frequency range of 0~50Hz. These models describe accurately the dynamics of compensation device in the 4 divided domains of the input frequency range of 0~50Hz, respectively. Micro-vibration disturbance can be compensated by feedback control strategy of switching four models appropriately according to the input frequency.

A Study on Arterial Road Network Improvement Based on Networking Analysis (Networking 기반의 간선도로의 망기능 분석방법론 연구)

  • Jung, Kabchae;Kang, Kyeong Pyo;Kim, Jung Wan
    • Journal of Korean Society of Transportation
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    • v.31 no.1
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    • pp.47-56
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    • 2013
  • The present study proposed a methodology to analyze the networking efficiency of arterial road networks. The methodology was motivated to design three-dimensional networks and to analyze the networking ability quantitatively, which is a novel approach compared to existing methods depending on the two-dimensional network definition and the qualitative analysis for improving arterial road networks. The method considered the interdependence between high-level freeways and low-level highways, the ITS-based information for traffic and road conditions, and the physical networking. These three factors were quantified by a networking index (NI), and the networking efficiency was measured by a networking rate (NR). The present study proved that the networking efficiency (NR) was influenced by travel information sharing (i.e., ITS) and physical factors. This supports the fact that the integrated improvements of physical and ITS factors are necessary for an arterial road. The proposed method was applied for an actual arterial road network. It was found that the nation-wide NR was higher than that for the metropolitan area, which might be due to the difficulty in switching between high- and low-level networks and the lack of ITS functions in the metropolitan area.

A Case Study of Family Therapy for Marriage Migrant Woman who Experienced Family Violence - Focusing on Chinese Woman Who Participated in Counseling alone - (가정폭력 피해 결혼이주여성의 가족치료 사례연구: 단독으로 상담에 참여한 중국출신 여성을 중심으로)

  • Moon, Jung Hwa
    • Korean Journal of Family Social Work
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    • no.55
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    • pp.91-128
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    • 2017
  • The purpose of this study is to develop an effective intervention strategy for marriage migrant woman in family therapy. For this purpose, we collected counseling cases of professional counselors who successfully completed counseling and attempted the qualitative analysis of treatment intervention strategies and effects. The results of the study were obtained by dividing the meaning units in the immigrant woman's statements made during the counseling process composed of a total of 6 sessions. The counselors were analyzed to have tried the following intervention strategies. They attempted the following six strategies: Helping emotional differentiation by searching for unresolved emotional problems, dealing with undifferentiation due to family projection process and love triangle, dealing with multi-generational transfer process of the original family relationship patterns and coping mechanism, shedding lihgt on ineffectiveness of inconsistent communication due to emotional oppression applying a communication model of MRI, switching client's awareness through reorganization, suggesting a way of communication that leads to real self. Such counselors' attempts resulted in positive changes and treatment effects were found to include first, cognitive insights and motivation for change, second, improved communication skills and third, anxiety reduction and self-differentiation. Due to their husbands' refusal to participate in counseling, marriage migrant women often get involved in counseling alone, so they tend to worry that the effectiveness of family therapy may be low but it was found that the proper intervention of the counselor could improve the ability of the wife to resolve conflicts, which would be a great help in solving problems such as family violence and this study is meaningful in that it provided the appropriate therapeutic intervention strategies needed.