• Title, Summary, Keyword: Super stability

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Design and Implementation of PIC/FLC plus SMC for Positive Output Elementary Super Lift Luo Converter working in Discontinuous Conduction Mode

  • Muthukaruppasamy, S.;Abudhahir, A.;Saravanan, A. Gnana;Gnanavadivel, J.;Duraipandy, P.
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.1886-1900
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    • 2018
  • This paper proposes a confronting feedback control structure and controllers for positive output elementary super lift Luo converters (POESLLCs) working in discontinuous conduction mode (DCM). The POESLLC offers the merits like high voltage transfer gain, good efficiency, and minimized coil current and capacitor voltage ripples. The POESLLC working in DCM holds the value of not having right half pole zero (RHPZ) in their control to output transfer function unlike continuous conduction mode (CCM). Also the DCM bestows superlative dynamic response, eliminates the reverse recovery troubles of diode and retains the stability. The proposed control structure involves two controllers respectively to control the voltage (outer) loop and the current (inner) loop to confront the time-varying ON/OFF characteristics of variable structured systems (VSSs) like POESLLC. This study involves two different combination of feedback controllers viz. the proportional integral controller (PIC) plus sliding mode controller (SMC) and the fuzzy logic controller (FLC) plus SMC. The state space averaging modeling of POESLLC in DCM is reviewed first, then design of PIC, FLC and SMC are detailed. The performance of developed controller combinations is studied at different working states of the POESLLC system by MATLAB-Simulink implementation. Further the experimental corroboration is done through implementation of the developed controllers in PIC 16F877A processor. The prototype uses IRF250 MOSFET, IR2110 driver and UF5408 diodes. The results reassured the proficiency of designed FLC plus SMC combination over its counterpart PIC plus SMC.

A Study on the Long-Term Care Insurance System prepare for the Super-Aged Society (초고령화 사회를 대비한 노인장기요양보험제도에 관한 연구)

  • Kim, Min-Ju;Hwang, Jun-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.10
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    • pp.395-405
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    • 2019
  • Korea is undergoing a change in its population structure, due to economic development, falling birth rates and the development of health care. As the population ages, the number of elderly people who have difficulty in daily life such as dementia and paralysis increases every day. The growth of nuclear families and the increased participation of women in society make it difficult to take care of elderly people who need long-term care at home. As the social problems resulting from this have emerged as serious problems, the government enacted and implemented the Long Term Care Insurance Act to improve the quality of life for the elderly subject to long-term care and to ease the burden of family support in order to solve such problems. Therefore, the present study explores ways to improve legal and institutional aspects, and seek mental and psychological measures for the stability of old life as well as the physical health of welfare.

The Effect of Rearing Knowledge on Rearing Satisfaction in Companion Animals (반려동물의 양육지식이 양육만족도에 미치는 영향)

  • Kim, Seok-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.333-337
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    • 2021
  • Companion animals are physically, mentally, and socially beneficial to humans, giving us great comfort in living in the Corona19 (COVID-19) era. It is also an era of the Fourth Industrial Revolution, featuring the convergence of information and communication technology. Korea, which is facing a super-aged society, has the highest suicide rate among OECD countries, and companion animals that are effective in emotional stability can be the answer. This study is about companion animals that are effective in stabilizing the emotions of the elderly, one of the major problems in the Republic of Korea, which is about to solve in a super-aged society with more than 20 percent of the elderly aged 65 or older, needs to solve. The impact of knowledge of raising companion animals on the satisfaction level of the elderly was investigated through the management and awareness of infectious diseases. Although the level of care of companion animals had a very significant (p<0.001) effect on the satisfaction of the companion animals, the recognition of infectious diseases has no statistical significance (p>0.05). Raising companion animals with knowledge of rearing increases the satisfaction level and can lead to a happier life. While personal learning is important, it is also believed that supporting education will be necessary as a policy consideration.

An Application of Construction Sequence Analysis for Checking Structural Stability of High-Rise Building under Construction (초고층 건물의 시공 중 구조적 안정성 검토를 위한 시공단계해석의 적용)

  • Eom, Tae-Sung;Kim, Jae-Yo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.3
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    • pp.211-221
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    • 2009
  • With recent trends of super-tallness, atypical plan shapes and zoning constructions in high-rise buildings, a structural stability of the building under construction is arising as a key issue for design and construction plan. To ensure the structural stability under construction, the differential column shortening of vertical members, the lateral displacement of tower frames, and differential settlement of raft foundation by unbalanced distributions of a tower self-weight before the completion of a lateral load resisting system should be checked by construction sequence analysis, which should be performed by systematic combinations with structural health monitoring, construction compensation program, and construction panning. This paper presents the scheme of zone-based construction sequence analysis by using the existing commercial analysis program, to check the stability of high-rise building under construction. This scheme is applied to 3-dimensional structural analysis for a real high-rise building under construction. The analysis includes real construction zoning plans and schedules as well as creep and shrinkage effects and time-dependent properties of concrete. The simplified construction sequence and assumed material properties were continuously updated with the change on construction schedule and correlations with in-situ measurement data.

THREE DIMENSIONAL FINITE ELEMENT ANALYSIS OF INTERNALLY CONNECTED IMPLANT SYSTEMS (내부연결방식 임플랜트 시스템의 삼차원 유한요소법적 연구)

  • Kim Yu-Lee;Cho Hye-Won;Lee Jai-Bong
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.1
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    • pp.85-102
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    • 2006
  • Statement of problem: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. Purpose: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. Material and method. The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the super structures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. Results: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. Conclusions: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.

Thermal Stability of Delithiated LiCoO2-organic Electrolyte for Lithium-Ion Rechargeable Batteries (리튬이온이차전지용 LiCoO2-유기전해액의 충전상태에 따른 열적 안정성)

  • Kim, Dong-Hun;Lee, Young-Ho;Shin, Hye-Min;Chung, Young-Dong;Doh, Chil-Hoon;Jin, Bong-Soo;Kim, Hyun-Soo;Moon, Seong-In;Oh, Dae-Hui;Kim, Ki-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.5
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    • pp.421-424
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    • 2007
  • Thermal behavior of $Li_{1-x}CoO_2$ has been investigated employing DSC (Differential Scanning calorimetry) and TGA (Thermogravimetry Analyzer), and the crystal parameters were calculated from XRD (X-ray diffraction).for the commercial rectangular pouch cell(1000 mAh).The cathode materials coated over aluminium foil current collector is made up of a blend consisting of active material $LiCoO_2$(size $20\;{\mu}m$, 94 wt%), conducting material super p black (SPB, 3 wt%) and binder polyvinylidene fluoride (PVDF, 3 wt%). The anode is a mix consisting of carbon (92 wt%) and PVDF(8 wt%) coated over copper foil. The cells for the experiments were first preconditioned by cycling three times and stabilized at OCV=3.0, 3.5, 4.2, 4.35 and 4.5 V. The stabilized cathode material was used for thermal and crystal parameter investigations.

Study of Supporting Location Optimization for a Structure under Non-uniform Load Using Genetic Algorithm (유전알고리즘을 이용한 비균일 하중을 받는 구조물의 지지 위치 최적화 연구)

  • Kim, G.H.;Lee, Y.S.;Kim, H.K.;Her, N.I.;Sa, J.W.;Yang, H.L.;Kim, B.C.;Bak, J.S.
    • Proceedings of the KSME Conference
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    • pp.1322-1327
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    • 2003
  • It is important to determine supporting locations for structural stability of a structure under non-uniform load in space interfered by other parts. In this case, There are many local optima with discontinuous design space. Therefore, The traditional optimization methods based on derivative are not suitable. Whereas, Genetic algorithm(GA) based on stochastic search technique is a very robust and general method. This paper has been presented to determine supporting locations of the vertical supports for reducing stress of the KSTAR(Korea super Superconducting Tokamak Advanced Research) IVCC(In-vessel control coil) under non-uniform electromagnetic load and space interfered by other parts using genetic algorithm. For this study, we develop a program combining finite element analysis with a genetic algorithm to perform structural analysis of IVCC. In addition, this paper presents a technique to perform optimization with FEM when design variables are trapped in an incongruent design space.

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Wear characteristics of boron nitride thin film for durability improvement of ultra- precision component (초정밀 부품의 내구성 향상을 위한 질화붕소 박막의 마멸 특성에 관한 연구)

  • Ku, Kyoung-Jin;Hwang, Byoung-Har;Lin, Li-Yu;Kim, Dae-Eun;Baik, Hong-Koo
    • Transactions of the Society of Information Storage Systems
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    • v.3 no.3
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    • pp.129-134
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    • 2007
  • Boron nitride (BN) is a highly attractive material for wear resistant applications of mechanical components. BN is super hard and it is the second hardest of all known materials. It also has a high thermal stability, high abrasive wear resistance, and in contrast to diamond, BN does not react with ferrous materials. The motivation of this work is to investigate the tribological properties of BN for potential applications in ultra-precision components for data storage, printing, and other precision devices. In this work, the wear characteristics of BN thin films deposited on DLC or Ti buffer layer with silicon substrate using RF-magnetron sputtering technique were analyzed. Wear tests were conducted by using a pin-on-disk type tester and the wear tracks were measured with a surface profiler. Experimental results showed that wear characteristics were dependent on the sputtering conditions and buffer layer. Particularly, BN coated on DLC layer showed better wear resistant behavior. The range of the wear rates for the BN films tested in this work was about 20 to $100{\mu}m^3$/cycle.

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Accurate electronic structures for Ce doped SiAlON using a semilocal exchange-correlation potential

  • Yu, Dong-Su;Jeong, Yong-Jae
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.438-438
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    • 2011
  • White light-emitting diodes (LEDs), the so-called next-generation solid-state lighting, offer benefits in terms of reliability, energy-saving, maintenance, safety, lead-free, and eco-friendly. Recently, rare-earth-doped oxynitride or nitride compounds have attracted a great deal of interest as a photoluminescent material because of their unique luminescent property, especially for white LEDs applications. Ce doped ${\beta}$-SiAlON has been studied as a wavelength conversion phosphor in white LEDs thanks to its high absorption rates, high quantum efficiency, and excellent thermal stability. Previously researches were not enough to understand the detail mechanism and characteristics of ${\beta}$-SiALON. The bandgap structures and electronic structures were not exact due to limitation of calculation methods. In this study, to elucidate the Ce doping effect on the SiAlON system, accurate band structures and electronic structure of the Ce doped ${\beta}$-SiAlON was intensively investigated using density functional theory calculations. In order to get a better description of the band gaps, MBJLDA method were used. We have found a single Ce atom site in ${\beta}$-SiAlON super cell. Furthermore, the density of state, band structure and lattice constant were intensively investigated.

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Development of an advanced atmospheric pressure plasma source with high spatial uniformity and selectiveness for surface treatment

  • Im, Yu-Bong;Choe, Won-Ho;Lee, Seung-Hun;Han, U-Yong;Lee, Jong-Hyeon;Lee, Sang-Gyun;Ha, Jeong-Min;Kim, Jong-Hun
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.176-177
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    • 2016
  • In the last few decades, attention toward atmospheric pressure plasma (APP) has been greatly increased due to the numerous advantages of those applications, such as non-necessity of high vacuum facility, easy setup and operation, and low temperature operation. The practical applications of APP can be found in a wide spectrum of fields from the functionalization of material surfaces to sterilization of medical devices. In the secondary battery industry, separator film has been typically treated by APP to enhance adhesion strength between adjacent films. In this process, the plasma is required to have high stability and uniformity for better performance of the battery. Dielectric barrier discharge (DBD) was usually adopted to limit overcurrent in the plasma, and we developed the pre-discharge technology to overcome the drawbacks of streamer discharge in the conventional DBD source which makes it possible to produce a super-stable plasma at atmospheric pressure. Simulations for the fluid flow and electric field were parametrically performed to find the optimized design for the linear jet plasma source. The developed plasma source (Plasmapp LJPS-200) exhibits spatial non-uniformity of less than 3%, and the adhesion strength between the separator and electrode films was observed to increase 17% by the plasma treatment.

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