• Title/Summary/Keyword: Self-balancing

Search Result 110, Processing Time 0.03 seconds

An Interleaved Five-level Boost Converter with Voltage-Balance Control

  • Chen, Jianfei;Hou, Shiying;Deng, Fujin;Chen, Zhe;Li, Jian
    • Journal of Power Electronics
    • /
    • v.16 no.5
    • /
    • pp.1735-1742
    • /
    • 2016
  • This paper proposes an interleaved five-level boost converter based on a switched-capacitor network. The operating principle of the converter under the CCM mode is analyzed. A high voltage gain, low component stress, small input current ripple, and self-balancing function for the capacitor voltages in the switched-capacitor networks are achieved. In addition, a three-loop control strategy including an outer voltage loop, an inner current loop and a voltage-balance loop has been researched to achieve good performances and voltage-balance effect. An experimental study has been done to verify the correctness and feasibility of the proposed converter and control strategy.

Fuzzy Learning Control for Ball & Beam System (볼과 빔 시스템의 퍼지 학습 제어)

  • Joo, Hae-Ho;Jung, Byung-Mook;Lee, Jae-Won;Lee, Hwa-Jo;Lee, Young
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.11a
    • /
    • pp.439-443
    • /
    • 1996
  • A fuzzy teaming controller is experimentally designed to control the ball k beam system in this paper. Although most fuzzy controllers have been built just to emulate human decision-making behavior, it is necessary to construct the rule bases by using a learning method with self-improvement when it is difficult or impossible to get them only by expert's experience. The algorithm introduces a reference model to generate a desired output and minimizes a performance index function based on the error and error-rate using the gradient-decent method. In our balancing experiment of the ball & beam system, this paper shows that the fuzzy control rules by learning are superior to the expert's experience.

  • PDF

All-Electron Relativistic SCF Calculations for Light Atoms and Diatomic Molecules; Correct Nonrelativistic Limit Calculations with a Relativistic Method

  • Baeck, Kyoung-Koo;Lee, Yoon-Sup
    • Bulletin of the Korean Chemical Society
    • /
    • v.12 no.6
    • /
    • pp.699-705
    • /
    • 1991
  • Procedures to perform reliable relativistic self-consistent-field (RSCF) calculations are described. Using light atoms and molecules, it is demonstrated that the present method always yields correct nonrelativistic limit by employing a sufficiently large value for the speed of light in RSCF calculations. Many problems associated with analytic expansions of the Dirac equations can be computationally avoided by kinetically balancing the basis sets for large and small component spinors. Results of RSCF calculations for Ne, Kr, $H_2$, and LiH indicate very small relativistic effects for these systems as expected. Trends found is these molecules, however, may be useful in understanding relativistic effects for molecules with similar valence electronic structures and heavier atoms.

Autophagy in the uterine vessel microenvironment: Balancing vasoactive factors

  • Lim, Hyunjung Jade
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.47 no.4
    • /
    • pp.263-268
    • /
    • 2020
  • Autophagy, which has the literal meaning of self-eating, is a cellular catabolic process executed by arrays of conserved proteins in eukaryotes. Autophagy is dynamically ongoing at a basal level, presumably in all cells, and often carries out distinct functions depending on the cell type. Therefore, although a set of common genes and proteins is involved in this process, the outcome of autophagic activation or deficit requires scrutiny regarding how it affects cells in a specific pathophysiological context. The uterus is a complex organ that carries out multiple tasks under the influence of cyclic changes of ovarian steroid hormones. Several major populations of cells are present in the uterus, and the interactions among them drive complex physiological tasks. Mouse models with autophagic deficits in the uterus are very limited, but provide an initial glimpse at how autophagy plays a distinct role in different uterine tissues. Herein, we review recent research findings on the role of autophagy in the uterine mesenchyme in mouse models.

Step-up Switched Capacitor Multilevel Inverter with a Cascaded Structure in Asymmetric DC Source Configuration

  • Roy, Tapas;Bhattacharjee, Bidrohi;Sadhu, Pradip Kumar;Dasgupta, Abhijit;Mohapatra, Srikanta
    • Journal of Power Electronics
    • /
    • v.18 no.4
    • /
    • pp.1051-1066
    • /
    • 2018
  • This study presents a novel step-up switched capacitor multilevel inverter (SCMLI) structure. The proposed structure comprises 2 unequal DC voltage sources, 4 capacitors, and 14 unidirectional power switches. It can synthesize 21 output voltage levels. The important features of the proposed topology are its self-voltage boosting and inherent capacitor voltage balancing capabilities. Furthermore, a cascaded structure of the proposed SCMLI with an asymmetric DC voltage source configuration is presented. The proposed topology and its cascaded structure are compared with conventional and other recently developed topologies in terms of different aspects, such as the required components to produce a specific number of output voltage levels, the total standing voltage (TSV) and peak inverse voltage of the structure, and the maximum number of switches in the conducting path. Furthermore, a cost function is developed to verify the cost-effectiveness of the proposed topology with respect to other topologies. The TSV of the proposed topology is significantly lower than those of other topologies. Moreover, the developed topology is cost-effective compared with other topologies. A detailed operating principle, power loss analysis, and selection procedure for switched capacitors are presented for the proposed SCMLI structure. Extensive simulation and experimental studies of a 21-level inverter structure prove the effectiveness and merits of the proposed SCMLI.

An Efficient Load Balancing Policy in P2P Contents Delivery System for Cyber Education (사이버 교육을 위한 P2P 기반 콘텐츠 전송시스템에서 효율적인 부하 분산 정책)

  • Kim, Jin-Il;Hwang, Yoon-Cheol
    • Journal of the Korea Society of Computer and Information
    • /
    • v.12 no.6
    • /
    • pp.31-39
    • /
    • 2007
  • To perform on-line cyber education, it is indispensable to delivery contents file to participant users. When users' requests occur simultaneously in a shot period, server falls into overload phase. A common to avoid overload is a software solution based on P2P, which does no cost any additional expense. But, in this solution, it yields many problems such as service delay and system failure because of peer self-control. In this paper we propose an efficient load balancing policy based on P2P system. which is the contents delivery system for cyber education system using idle computing power in the proposed solution, we present server selection scheme called P2P-Pattern method, which results in minimum service delay. we can see that our scheme outperforms previous scheme.

  • PDF

A Comparison Study of Walk and Balance Ability of Women Elderly with or Without Falls Experience (낙상 경험 유무에 따른 여성 노인의 보행과 균형 능력에 관한 연구)

  • Hwang, Byeong-Jun;Kim, Jong-Woo;Seo, Hyon-Kyu
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
    • /
    • v.17 no.2
    • /
    • pp.19-24
    • /
    • 2011
  • Background: The elderly are likely to fall due to physical and mental atrophies, and experiencing falls may result in fear of falls and lack of self-confidence, which also leads to hesitation to physical activities and changes in walk and balance, the major variables in independent daily life. Methods: In three senior citizen centers located in D city, 22 elderly women aged 65 or older were chosen, and they filled in the questionnaire which included their agreement to voluntarily participate in the survey and medical histories. As to whether they had falls experience, the medical history items in the questionnaire asked them if they had falling down or falls once a year, twice for the three years. The objects were divided to NFE (non-falls experience) and FE (falls experience). Results: 1. As to walking abilities, significant difference was found between NFE and FE regarding walk width, stepping with two feet, and stride length while there was no significant different in terms of cadence. 2. As to balancing abilities, was significant difference between NFE and FE in terms of the physical body center area. As to the sit-to-stand, tandom gait test, no significant difference was found, and neither in the timed up and go test. Conclusions: The elderly with falls experience has inferior walking and balancing abilities to those without falls experience, and thus they are more exposed to the risks of falls.

  • PDF

An Incentive Regulation of Access Charges under Incomplete Information (불완전 정보하에서 접속료의 최적규제에 관한 연구)

  • Jung, Choong-Young
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.32 no.11B
    • /
    • pp.700-708
    • /
    • 2007
  • This paper considers an incentive regulation in the telecommunications industry with respect to the sale of retail and access services. This regulation scheme induces the monopoly carrier who owns bottleneck facilities to adopt socially optimal outcomes when providing access and retail services. It is well known that upstream carriers can realize an integrated level of profit, without integration, by means of a two-part tariff. First, this paper introduces a framework for regulating an access and retail price combined with budget balancing. Second, this paper introduces two-part tariff (price discrimination) scheme for both access (upstream) and retail (downstream) services and discusses the resulting implications for incentive regulation when the regulator has incomplete information about cost functions. By imposing a self-selection mechanism, the regulator can induce firms to adopt socially optimal prices in both access and retail markets.

The Effect of Postural Yinyang Correction of Temporomandibular Joint for Temporomandibular Disorder

  • Lee, Seung-Jeong;Ryu, Hye-Min;Kim, Su-Gyeong;Park, Eun-Jin;Lim, Jae-Eun;Lee, Young-Jun;Song, Choon-Ho;Yoon, Hyun-Min;Kim, Cheol-Hong
    • Journal of Acupuncture Research
    • /
    • v.35 no.3
    • /
    • pp.129-137
    • /
    • 2018
  • Background: The purpose of this study was to determine the effect of Postural Yinyang correction of the temporomandibular joint (functional cerebrospinal therapy) on temporomandibular disorder. Methods: Medical records of 21 outpatients were reviewed who were diagnosed with temporomandibular joint disorder, unspecified (K0769) and treated at the Department of Acupuncture & Moxibustion, Dong-Eui University Korean Medicine Hospital from May $1^{st}$, 2017 to April $30^{th}$, 2018. Patients received more than 10 treatments of upper cervical manipulation and performed self-exercise therapy more than 3 times a day and wore an accurate balancing appliance in the oral cavity for more than 8 hours per day. To estimate the efficacy, visual analogue scale (VAS), numerical rating scale (NRS), maximum mouth opening (MMO), symptom intensity scale (SIS), max SIS (MSIS), symptom frequency scale (SFS), mandibular function impairment questionnaire (MFIQ) and 5-point Likert scale were used. Results: NRS and MSIS were significantly improved during each period. VAS, MMO, SIS, and SFS were significantly improved during each period, except the period from the $8^{th}$ to $10^{th}$ visit. MFIQ score was significantly improved during the period from the $1^{st}$ to $10^{th}$ visit. In the 5-point Likert scale, the results showed a high patient satisfaction with the treatment. Conclusion: These results showed that functional cerebrospinal therapy using an accurate balancing appliance, may be useful for reducing the symptoms of temporomandibular disorder.

Development of a Self Balancing Electric Wheelbarrow (자기 균형 기능이 있는 외발 전동 손수레 개발)

  • Lee, Myung-Sub;Sung, Young-Whee
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.21 no.1
    • /
    • pp.21-28
    • /
    • 2020
  • In this paper, a new type of electric wheelbarrow is proposed and developed. The developed electric wheelbarrow is equipped with an attitude reference system(ARS) sensor, which consists of 3-axis acceleration sensor and 2-axis Gyro sensor so that it can estimate pitch angle and roll angle. When an operator tilts the wheelbarrow up and down, the pitch angle is detected. The sign of the pitch angle is interpreted as the operator's intention for moving the wheelbarrow forward or backward and the controller drives the wheel of the wheelbarrow with the velocity according to the magnitude of the detected pitch angle. A cargo box of the wheelbarrow is designed to rotate and is controlled to maintain level always, so an operator can handle the electric wheelbarrow easily and safely. The wheelbarrow consists of an in-wheel motor, a DC motor, motor drives, an ARS sensor considering economical use in industrial field. Three experiments are performed to verify the feasibility and stability of the electric wheelbarrow.