Joint Energy Management System of Electric Supply and Demand in Houses and Buildings

Sungjin Lee,Beom Kwon,Sanghoon Lee IEEE 2014 IEEE transactions on power systems Vol.29 No.6

<P>In this paper, a joint scheduling scheme for the electric supply and demand of Home Energy Management System (HEMS) and Building Energy Management System (BEMS) via energy management in houses and buildings is presented. To reflect ongoing policy, the Korea Electric Power COoperation (KEPCO) tariff is employed to formulate the optimization problem in terms of the sequential management procedure of prediction, supply control and demand control. As a result, an optimal electric supply pattern to produce the minimum energy cost can be obtained under a given curtailment. From simulation, the proposed scheduling scheme demonstrates greater reliability and adaptation for the interruptible load (IL) than the day-ahead method.</P>

BUCKET: Scheduling of Solar-Powered Sensor Networks via Cross-Layer Optimization

Sungjin Lee,Beom Kwon,Sanghoon Lee,Bovik, Alan Conrad IEEE 2015 IEEE Sensors Journal Vol. No.

<P>Renewable solar energy harvesting systems have received considerable attention as a possible substitute for conventional chemical batteries in sensor networks. However, it is difficult to optimize the use of solar energy based only on empirical power acquisition patterns in sensor networks. We apply acquisition patterns from actual solar energy harvesting systems and build a framework to maximize the utilization of solar energy in general sensor networks. To achieve this goal, we develop a cross-layer optimization-based scheduling scheme called binding optimization of duty cycling and networking through energy tracking (BUCKET), which is formulated in four-stages: 1) prediction of energy harvesting and arriving traffic; 2) internode optimization at the transport and network layers; 3) intranode optimization at the medium access control layer; and 4) flow control of generated communication task sets using a token-bucket algorithm. Monitoring of the structural health of bridges is shown to be a potential application of an energy-harvesting sensor network. The example network deploys five sensor types: 1) temperature; 2) strain gauge; 3) accelerometer; 4) pressure; and 5) humidity. In the simulations, the BUCKET algorithm displays performance enhancements of ~12-15% over those of conventional methods in terms of the average service rate.</P>

K-DEMO 핵융합실증로의 에너지원항: 중수소-삼중수소 반응에 따른 블랑켓 및 디버터 구조물의 붕괴열과 비방사능 평가

김범석(Beom Seok Kim),임기학(Kihak Im),김홍택(Hong-tack Kim),권성진(Sungjin Kwon),홍석호(Suk-ho Hong) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11

In the preliminary research phase, we quantify potential energy from the activation of major in-vessel components such as breeding blanket and divertor due to neutron generation during a D-T fusion reaction in K-DEMO. After two years of full fusion operation of K-DEMO, the decay heat which readily provokes potential behavior of hazardous inventories is estimated as 55.6 ㎿ and 8.40 ㎿ from activated blankets and divertors, respectively. Particularly tungsten first wall of an equatorial blanket shows a considerable amount of decay heat of 149 W/㎏, while it is about 92.3 W/㎏ for a structural material of reduced activation ferritic martensitic (RAFM) steel. Local specific radioactivity in the blanket reaches 2.42×1015 Bq/㎏, and 2.39×1014 Bq/㎏ for W first wall and RAFM steel structures, respectively. We will demonstrate the cooling temperature as a function of decay time is an important factor to assess thermal behavior of breeding blanket and divertor, and it should be implemented into safety system to secure the components as intact as possible against thermal failure. We will show that all in-vessel components can be managed within low level limits on their activation in accordance with regulatory guidelines for nuclear safety concerns. The results of this study will be implemented in a pre-conceptual design of K-DEMO and will contribute to the establishment of a regulatory framework.

K-DEMO 핵융합실증로의 증식블랑켓 방사화 특성 평가 및 붕괴열 처리 설계

김범석(Beom Seok Kim),임기학(Kihak Im),김홍택(Hong-Tack Kim),권성진(Sungjin Kwon),박종성(Jong Sung Park) 대한기계학회 2019 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.7 No.1

국내외적으로 최근 이슈가 되고 있는 에너지 문제의 궁극적인 해결책으로서 핵융합발전기술이 대두되고 있다. 현재 국내에서는 향후 추진될 상용발전설비의 건설 및 운용에 앞서, 핵융합기술과 설비의 과학적, 공학적 실증을 위한 한국형 핵융합실증로(K-DEMO) 선행개념연구가 진행되고 있다. K-DEMO에서는 연료로 사용 될 삼중수소의 증식과 연속적인 핵융합 반응을 위한 중성자 증배를 위하여 증식블랑켓이 필수적으로 적용되어야 한다. 하지만 토카막의 운용과정에서 발생되는 중성자로 인하여, 증식블랑켓은 필연적으로 방사화가 진행되고 붕괴열을 발생하게 된다. 플라즈마 운전 직후 증식블랑켓의 구성 재질인 저방사화합금 및 텅스텐에서 발생되는 붕괴열량은 수십 kW 에 달한다. 이에 본 연구에서는 중성자로 인한 증식블랑켓의 방사화 특성을 살펴보고, 이로 인한 붕괴열 특성을 평가해 보도록 한다. Fusion technology is attracting attention as the ultimate new source of energy based on the abundance of its fuels and the social and environmental acceptability. The Korean fusion demonstration tokamak reactor (K-DEMO), a facility for the demonstration of scientific and engineering feasibility, is currently in the pre-conceptual design phase. A breeding blanket, which is essential in K-DEMO tokamak, is an important mechanical and functional component for both tritium breeding and neutron multiplying. However it must be radio-activated due to the neutron irradiation, and thus accompany decay heat generation during their maintenance. A component of reduced activation ferritic martensitic (RAFM) steel layer and tungsten first wall accompanies significant decay heats by tens of kilowatts after the plasma shutdown. We evaluate their radio-activated characteristics under the fusion neutron irradiation and demonstrate that thermal managements should be taken into account in the light of heat transfer aspects of cooling.

솔 - 젤 법을 이용한 Pb(Zr, Ti)O₃ 박막의 성장 및 전기적 특성에 관한 연구

김봉주(Bong Ju Kim),전성진(Sungjin Jun),이재찬(Jaichan Lee),유지범(Ji Beom Yoo) 한국진공학회(ASCT) 1999 Applied Science and Convergence Technology Vol.8 No.4(1)

MEMS 소자 제작을 위하여 압전체로서 Pb(Zr,Ti)O₃ (以下 PZT)박막 및 전극물질로 전도성 산화물인(La,Sr)CoO₃ (以下 LSCO) 박막을 솜-젤 법으로 제작하였다. 실리카 후막과 PZT 박막의 접착성의 개선을 위해, 그리고 하부 전극으로 사용된 LSCO 박막은 물을 용매로 제작된 용액을 이용하여 제작되었으며 실리카와의 계면상태 향상을 위하여 고분자 계통의 첨가제인 poly vinyl alcohol(PVA)를 첨가하였다. PZT 박막에 사용된 용액은 보다 용이한 후막화를 위하여 높은 점성과 끓는점을 가지는 1,3-propanediol을 용매로 사용하였으며 출발물질의 합성에 있어서 반응성은 높지만 안정성이 약한 propoxide 계열의 특성을 보완하기 위하여 안정성이 높은 특성을 가지는 acetylacetone으로 부분치환을 시켜 제조하였다. 제조된 용액으로 스핀코팅 및 열처리를 통하여 박막을 성장시켰으며 약 0.8~1 ㎛ 두께의 균열이 없는 PZT 박막을 LSCO/SiO₂상에서 성장시킬 수 있었다. PZT 박막의 유전상수 및 유전손실 값은 각각 900~1200, 2~5%이었으며 Mach-Zehnder interferometer를 통해서 측정된 d₃₃ 압전상수는 100 kV/㎝의 전기장 하에서 200 pm/V이었다. Pb(Zr_(0.52)Ti_(0.48))O₃ (PZT) thick films as an actuating material with conducting oxides, (La_(0.5)Sr_(0.5)) CoO₃ (LSCO), have been fabricated by sol-gel method for Optical Micro-Electro-Mechanical System(MEMS) devices, in which PZT/LSCO/SiO₂ structures were used. In order to improve the adhesion between the silica and electrode, conducting oxides (LSCO) was used. Poly vinyl alcohol (PVA) was added to LSCO solution in order to enhance the wetting behavior of a water-based LSCO precursor solution and further to improve the adhesion between LSCO and SiO₂ layers. PZT films were made using 1-3 propanediol based precursor solution which has a high viscosity and a boiling point appropriate for thick film fabrication. In the precursor solution, Ti-propoxide and Zr-propoxide are partially substituted with acetylacetone to achieve the solution stability while maintaining reactivity. Crack free PZT films (0.8~1㎛) have been successfully fabricated at crystallization temperatures above 700℃. Dielectric constants and dielectric losses of the PZT films were 900~1200 and 2~5%, respectively. Piezoelectric properties of PZT films were measured by modified Mach Zehnder interferometer. Piezoelectric constant d₃₃ of the PZT films constrained by a substrate were 200 pm/V at 100 kV/㎝.

Co/Ni 복합실리사이드의 메탈 콘택 건식식각 안정성 연구

송오성,범성진,김득중,Song Ohsung,Beom Sungjin,Kim Dugjoong 한국재료학회 2004 한국재료학회지 Vol.14 No.8

Newly developed silicide materials for ULSI should have the appropriate electrical property of low resistant as well as process compatibility in conventional CMOS process. We prepared $NiCoSi_x$ silicides from 15 nm-Co/15 nm-Ni/Si structure and performed contact dry etch process to confirm the dry etch stability and compatibility of $NiCoSi_x$ layers. We dry etched the photoresist/SiO/silicide/silicon patterns with $CF_4\;and\;CHF_3$ gases with varying powers from 100 to 200 W, and pressures from 45 to 65 mTorr, respectively. Polysilicon and silicon active layers without silicide were etched $0\sim316{\AA}$ during over etch time of 3min, while silicon layers with proposed $NiCoSi_x$ silicide were not etched and showed stable surfaces. Our result implies that new $NiCoSi_x$ silicides may replace the conventional silicides due to contact etch process compatibility.

Large-Area Graphene Films by Simple Solution Casting of Edge-Selectively Functionalized Graphite

Bae, Seo-Yoon,Jeon, In-Yup,Yang, Jieun,Park, Noejung,Shin, Hyeon Suk,Park, Sungjin,Ruoff, Rodney S.,Dai, Liming,Baek, Jong-Beom American Chemical Society 2011 ACS NANO Vol.5 No.6

<P>We report edge-selective functionalization of graphite (EFG) for the production of large-area uniform graphene films by simply solution-casting EFG dispersions in dichloromethane on silicon oxide substrates, followed by annealing. The resultant graphene films show ambipolar transport properties with sheet resistances of 0.52–3.11 kΩ/sq at 63–90% optical transmittance. EFG allows solution processing methods for the scalable production of electrically conductive, optically transparent, and mechanically robust flexible graphene films for use in practice.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-6/nn201072m/production/images/medium/nn-2011-01072m_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn201072m'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn201072m'>ACS Electronic Supporting Info</A></P>