• Title/Summary/Keyword: MPP+

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An Improved MPPT Converter with Current Compensation Method for Small Scaled PV-Applications (소규모 태양광 발전시스템을 위한 전류보상기법을 갖는 향상된 MPP 추적 컨버터)

  • 이동윤;노형주;현동석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.8 no.2
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    • pp.143-150
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    • 2003
  • An improved MPPT converter with current compensation method for small-scaled PV-applications is presented in this paper. The proposed method implements maximum power point tracking (MPPT) by variable reference current which is continuously changed during one sampling period. Therefore, the Power transferred to the load is increased above 9% by the proposed MPPT converter with current compensation method. As a result, the utilization efficiency of Photovoltaic (PV)-panel can be increased. In addition, as it doesn't use digital signal processor (DSP), this MPPT method has the merits of both a cost efficiency and a simple control circuit design. Therefore, it is considered that the proposed MPPT method is proper to low power, low cost PV-applications. The concept and control principles of the proposed Un moth()d are explained in detail and its validity of the proposed method is verified through several simulated results.

Comparative Analysis of Plantar Pressure and Comfort Level in Developed-Domestic and Import Comfort Shoes for Elderly (고령층용 국내 개발 및 수입 컴포트화의 족저압 및 착화감 비교 분석)

  • Kim, Jae-Won;Choi, Jin-Seung;Park, Tae-Hyun;Tack, Gye-Rae;Choi, Kook-Lyeol;Lee, Sung-Jae
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.4
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    • pp.442-449
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    • 2013
  • This study was to compare a domestic comfort shoes to the popular import(SAS$^{(R)}$) to gain a better understanding in biomechanical characteristics for shoe design for the elderly. For each shoe type, morphologic dimensions, shock absorption, and flexibility were assessed. From subjects(n = 20, $72.4{\pm}5.5$ years, $67.7{\pm}7.9$ kg), mean peak pressure(MPP) and contact area(CA) at the plantar surface were analyzed. The domestic shoes reflecting anatomic contour of the plantar surfaces of Asians resulted in wider CA(by 30.4 $cm^2$), higher shock absorption(by 2.4%) and stiffness(by 0.5 N/mm) than the import. With the domestic shoes, significantly less MPPs were found at the forefoot(by 42~49%) regions(p < .05) and higher CA was noted additionally at hallux and lessor toes(by 26~63%). More anatomically-contoured insole and favorable mechanical characteristics may help reduce the plantar pressures more effectively and more evenly, especially across the central forefoot and midfoot regions of the plantar surface, especially for the design of the comfort shoes for the elderly.

Dual-Algorithm Maximum Power Point Tracking Control Method for Photovoltaic Systems based on Grey Wolf Optimization and Golden-Section Optimization

  • Shi, Ji-Ying;Zhang, Deng-Yu;Ling, Le-Tao;Xue, Fei;Li, Ya-Jing;Qin, Zi-Jian;Yang, Ting
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.841-852
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    • 2018
  • This paper presents a dual-algorithm search method (GWO-GSO) combining grey wolf optimization (GWO) and golden-section optimization (GSO) to realize maximum power point tracking (MPPT) for photovoltaic (PV) systems. First, a modified grey wolf optimization (MGWO) is activated for the global search. In conventional GWO, wolf leaders possess the same impact on decision-making. In this paper, the decision weights of wolf leaders are automatically adjusted with hunting progression, which is conducive to accelerating hunting. At the later stage, the algorithm is switched to GSO for the local search, which play a critical role in avoiding unnecessary search and reducing the tracking time. Additionally, a novel restart judgment based on the quasi-slope of the power-voltage curve is introduced to enhance the reliability of MPPT systems. Simulation and experiment results demonstrate that the proposed algorithm can track the global maximum power point (MPP) swiftly and reliably with higher accuracy under various conditions.

Effects of Movement When Using Visual Media to Determine Encounter Standards1a (휴양지역의 조우 평가기준 설정을 위한 시각매체의 활용시 움직임의 효과)

  • Kim, Sang-Oh;Shelby, Bo
    • Korean Journal of Environment and Ecology
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    • v.23 no.4
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    • pp.309-316
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    • 2009
  • The usefulness of media representations for assessing normative standards depends in part on how accurately media reflect "on-the-ground" resource conditions. This study compared encounter standards based on still and moving pictures to assess movement effects. The study location was the Jungmoeri area of Mudeungsan Provincial Park (MPP) in Korea. A total of 50 college students participated in a laboratory experiment where they evaluated still and moving pictures constructed using Photoshop and Flash computer programs. For the maximum acceptable number (MAN), however, there was no significant difference of ratings between still and moving pictures, and the overall encounter norm curves were nearly identical. There were some "method findings" for ordering effects and percent of people moving, but for a resource manager developing standards there was no advantage to the more complex logistics of using moving pictures to assess this particular impact. The trade-offs of using more sophisticated media are discussed, and more research is needed to further explore factors such as movement of sound in evaluation of other resource conditions.

A High PErformance Lookup Controller for ATM based IP Packet Forwarding Engine (ATM 기반 IP 패킷 포워딩 엔진을 위한 고성능 룩업 제어기)

  • Choi, Byeong-Cheol;Kwak, Dong-Yong;Lee, Jeong-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4B
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    • pp.298-305
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    • 2003
  • In this paper, we proposed a high performance lookup controller for IP packet forwarding engine of ATM based label edge routers. The lookup controller is designed to provide services such as MPLS, VPN, ELL, and RT services as well as the best effort. For high speed searching for IP addresses, we employed a TCAM based hardware search device not using traditional algorithmic approaches. We also implement lookup control functions into FPGA for fast processing of packet header and lookup control. The proposed lookup controller is designed to support differenciated services for users and to process in pipelined mechanism for performance improvement. A two-step search scheme is also applied to perform lookup for the key combined with multi-field of packet header. We found that the proposed lookup controller provides the performance of about 16M packets per second through simulations.

The development and operation characteristics analysis of PCS applied PV Output Senseless (POS) MPPT (PV Output Senseless (POS) MPPT 제어법이 적용된 단상 PCS 개발 및 운전특성 분석)

  • Lee, Seok-Ju;Park, Hae-Yong;Kim, Gyeong-Hun;Seo, Hyo-Ryong;Park, Min-Won;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.226-227
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    • 2007
  • The purpose of this study for photovoltaic (PV) generation system is to keep the output power of photovoltaic cells maximized under any weather conditions. In a conventional MPPT (Maximum Power Point Tracking) control method, both voltage and current coming out from PV array have to be fedback. Thus, the system has a complex structure, and may fail to track MPP of PV array when unexpected weather conditions happen. This paper proposes a novel PV Output Senseless (POS) control method to solve the mentioned problem. The main advantage of this method is that the current flowing into load is the only one considerable factor. In case of a huge PV generation system, it can be operated much more safely than the conventional system. To verify this theory, results that compare and analyze the simulated data with experimental data under real weather condition of the manufactured PV generation system are shown in this paper. Authors vividly states that this theory uses constant resistors and variable resistors of DC-DC converter in PV system. Authors emphasize that it is a very useful method to maximize power from PV cells to load with only the feedback of load current. Authors also emphasize that this theory is applicable in case of the PCS in PV power generation system.

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Increased Slc6a4 Expression Associated with Decreased Dopaminergic Neurons in an MPTP Induced Parkinsonism Mouse Model (파킨슨병 동물 모델에서 도파민세포의 감소와 관련된 Slc6a4 발현의 증가)

  • Yeo, Sujung
    • Korean Journal of Acupuncture
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    • v.38 no.3
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    • pp.133-139
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    • 2021
  • Objectives : Parkinson's disease is a neurodegenerative disease caused by a decrease in the dopaminergic neurons in the substantia nigra. The abnormal expression of solute carrier family 6 member 4 (Slc6a4) has been reported in patients with Parkinson's disease. Methods : In this study, we used MPTP to examine the changes in the expression of Slc6a4 in the brain of mice with Parkinson's disease and investigate its effect on dopaminergic neuronal cell death. Results : In the examination of the Slc6a4 expression in the substantia nigra of MPTP-treated mice for 4 weeks. The gene expression was increased compared to the normal group. To investigate the relationship between Slc6a4 and dopaminergic neurons, we performed a study using siRNA of Slc6a4 in the dopaminergic neuronal cell line SH-SY5Y. Using the siRNA of Slc6a4 to evaluate gene expression, it revealed that the tyrosine hydroxylase (TH) expression increases when Slc6a4 decreases. Moreover, this confirms its effects on the dopaminergic neurons. Additionally, through the evaluation of factors related to apoptosis, in particular, it was established that the value of bax/bcl2 decreased and was affected. These results suggest that a decreased Slc6a4 expression induces an increase in TH expression, providing a mechanism of action for dopaminergic neurons regulated by Slc6a4 expression. Conclusions : Slc6a4 is deemed to be involved in the regulation of dopaminergic neurons, suggesting that an increased Slc6a4 expression induced by MPTP may influence a reduction of dopaminergic neurons.

Glycolysis Mediated Sarcoplasmic Reticulum Ca2+ Signal Regulates Mitochondria Ca2+ during Skeletal Muscle Contraction (근수축시 해당작용에 의한 근형질 세망의 Ca2+ 변화가 미토콘드리아 Ca2+ 증가에 미치는 영향)

  • Park, Dae-Ryoung
    • Exercise Science
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    • v.26 no.3
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    • pp.229-237
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    • 2017
  • PURPOSE: This study was to investigate the Glycolysis mediated sarcoplasmic reticulum (SR) $Ca^{2+}$ signal regulates mitochondria $Ca^{2+}$ during skeletal muscle contraction by using glycolysis inhibitor. METHODS: To examine the effect of Glycolysis inhibitor on SR and mitochondria $Ca^{2+}$ content, we used skeletal muscle fiber from gastrocnemius muscle. 2-deoxy glucose and 3-bromo pyruvate used as glycolysis inhibitor, it applied to electrically stimulated muscle contraction experiment. Intracellular $Ca^{2+}$ content, SR, mitochondria $Ca^{2+}$ level and mitochondria membrane potential (MMP) was detected by confocal microscope. Mitochondrial energy metabolism related enzyme, citric acid synthase activity also examined for mitochondrial function during the muscle contraction. RESULTS: Treatment of 2-DG and 3BP decreased the muscle contraction induced SR $Ca^{2+}$ increase however the mitochondria $Ca^{2+}$ level was increased by treatment of inhibitors and showed and overloading as compared with the control group. Glycolysis inhibitor and thapsigargin treatment showed a significant decrease in MPP of skeletal muscle cells compared to the control group. CS activity significantly decreased after pretreatment of glycolysis inhibitor during skeletal muscle contraction. These results suggest that regulation of mitochondrial $Ca^{2+}$ levels by glycolysis is an important factor in mitochondrial energy production during skeletal muscle contraction CONCLUSIONS: These results suggest that mitochondria $Ca^{2+}$ level can be regulated by SR $Ca^{2+}$ level and glycolytic regulation of intraocular $Ca^{2+}$ signal play pivotal role in regulation of mitochondria energy metabolism during the muscle contraction.

Design of a High-Speed Data Packet Allocation Circuit for Network-on-Chip (NoC 용 고속 데이터 패킷 할당 회로 설계)

  • Kim, Jeonghyun;Lee, Jaesung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.459-461
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    • 2022
  • One of the big differences between Network-on-Chip (NoC) and the existing parallel processing system based on an off-chip network is that data packet routing is performed using a centralized control scheme. In such an environment, the best-effort packet routing problem becomes a real-time assignment problem in which data packet arriving time and processing time is the cost. In this paper, the Hungarian algorithm, a representative computational complexity reduction algorithm for the linear algebraic equation of the allocation problem, is implemented in the form of a hardware accelerator. As a result of logic synthesis using the TSMC 0.18um standard cell library, the area of the circuit designed through case analysis for the cost distribution is reduced by about 16% and the propagation delay of it is reduced by about 52%, compared to the circuit implementing the original operation sequence of the Hungarian algorithm.

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An Exploratory Analysis School-based Intervention Studies to Prevent Smoking by American Adolescents (미국의 청소년 흡연예방을 위한 중재 프로그램의 현황)

  • Jung, Hye-Sun;Ha, Yeong-Mi;Jhang, Won-Gi;Lee, Ji-Won;Yi, Yun-Jeong;Yun, Soon-Nyung
    • Journal of the Korean Society of School Health
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    • v.21 no.2
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    • pp.119-134
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    • 2008
  • Purpose: The purpose of this study is to understand a variety of intervention studies to prevent smoking by adolescents in U.S. and find out implications for Korea. Methods: This study reviewed articles found in the internet and analysed the data of US DHHS and CDC. Results: The School Health Policies and Programs Study (SHPPS) is a national survey periodically conducted to assess school health policies and programs of U.S. The main components of SHPPS are health education and physical education, health services, mental health and social services, school policies, and school environments. The CDC guidelines for school health programs to prevent tobacco use and addiction are composed of policy, instruction, curriculum, training, family involvement, tobacco-use cessation efforts, and evaluation. School-based interventions to prevent smoking can be classified into the categories of information-giving curricula, social competence curricula, social influence approaches, combined methods draw on social competence and social influence approaches and multi-modal programmes and Youth Empowerment study. The key programs for adolescent smoking prevention are ALERT Project, HSPP, TNT Project, MPP, NC YES. Conclusions: As smoking is often the first step of unhealthy behaviour such as alcohol drinking, illegal drugs, and violence, smoking prevention programmes for adolescents in U.S. have been comprehensive school-based health programs. In smoking prevention programs for adolescents, CDC plays a critical role by supporting survey, research, policy, and funds. The effectiveness of the programs was high when it was based on school and involved parents, community, and mass media. As the effect of each programme is not expected to last for a long time, consistent repetition of these interventions is essential. Current smoking prevention programs for adolescents are exploring the empowerment approach focused on the active involvement of participants rather than traditional approaches using order and discipline.