• Title/Summary/Keyword: energy index

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The Variation of Sedimentary Rock Strength due to Weathering (풍화에 따른 퇴적암의 강도 변화)

  • 배우석;이봉직;오세욱;이종규
    • Journal of the Korean Society of Safety
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    • v.18 no.1
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    • pp.89-93
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    • 2003
  • The failure of rock slopes were influenced by weathering, which causes change in the shear strength. The weathering is also directly related to slaking and swelling characteristics. In the paper, the core of diameter loom was obtained by digging on rock slope of Kong-ju in Korea and then EDX(Energy Dispersive X-ray spectrometer) analysis was carried out to verified element of chief rock-forming minerals. Uniaxial compression tests, slaking tests, and point load test are performed to study engineering characteristics of conglomerate and red shale. As a results of slaking test, slaking index of conglomerate indicate range of 85.11-99.58 and shale indicate 58.37-99.23. Therefore, it is recognized that the resistance of shale to weathering decreases in shallow depth and it greatly influences the strength of rock. The result of uniaxial compression test and Point load test show that the strength of sedimentary such as conglomerate and red shale has an influence on both weathering and saturation.

THE DYNAMICAL EVOLUTION OF GLOBULAR CLUSTERS WITH STELLAR MASS LOSS

  • Kim, Chang-Hwan;Chun, Mun-Suk;Min, Kyung-W.
    • Journal of Astronomy and Space Sciences
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    • v.8 no.1
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    • pp.11-23
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    • 1991
  • The dynamical evolution of globular clusters is studied using the orbit-averaged multicomponent Fokker-Planck equation. The original code developed by Cohn(1980) is modi-fied to include the effect of stellar evolutions. Plommer's model is chosen as the initial density distribution with the initial mass function index $\alpha$=0.25, 0.65, 1.35, 2.35, and 3.35. The mass loss rate adopted in this work follows that of Fusi-Pecci and Renzini(1976). The stellar mass loss acts as the energy source, and thus affects the dynamical evolution of globular clusters by slowing down the evolution rate and extending the core collapse time Tcc. And the dynamical length scale $$R_c, $$R_h is also extended. This represents the expansion of cluster due to the stellar mass loss.

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Experimental Study on the Hysteretic Behavior of R/C Low-Rise Shear Walls under Cyclic Loads (반복하중을 받는 철근콘크리트 저형 전단벽의 이력거동에 관한 실험적 연구 (I))

  • 최창식;이용재;윤현도;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • 1991.04a
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    • pp.75-80
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    • 1991
  • Results of an experimental investigation of low-rise reinforced concrete shear walls with rectangular cross section under cyclic loads are discussed and evaluated. Two half scale models of test specimens with height to length ratio of 0.75 were experimented. The dimension of all walls is 1500mm wide $\times$ 950 mm high $\times$ 100 mm thick for all specimens and the section of all boundary at both ends is 100 mm $\times$ 200mm. Main variables are : horizontal shear reinforcement ratios and reinforcement details(including crossed diagonal shear reinforcements in SWR2 specimen) In SWR2 specimen, maximum strength and consequently dissipating energy index were 1.15~1.21 and 1.48 times greater than those of SWR1 specimen, respectively.

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A Study on the Comparison of the PV Module Generation from Daylight Irradiation and Indoor Lighting Savings with Lighting Simulation (일사량 분석을 통한 PV모듈 발전량과 시뮬레이션을 이용한 실내 조명에너지 절감량 비교)

  • Park, Yoon-Min;Hong, Seong-Kwan;Choi, An-Seop
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.12
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    • pp.17-24
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    • 2010
  • Recently, BIPV system which is good enough for maintenance and functions with the shading system is being used. However BIPV system with the shading system is different from existing PV module because of using flexible PV module. Prior to the application of the BIPV system, the clearness index was calculated by Erbs et al.(1982) and analyzed for the amount of electric power generation of sky irradiance with measured data. To predict electric lighting energy savings in daylit space, electric lighting power savings with amount of PV module electric power generation was compared by using Relux 2010 software in this study.

Evaluation of Irregular Disturbances to Ships in Autopilot Navigation (자동조타로써 항행하는 선박에 작용하는 불규칙 외란 추정법에 관한 고찰)

  • 이경우;손경호;김진형
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1995.04a
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    • pp.65-92
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    • 1995
  • The final aim of our research project is a study on assessment of automatic steering system of ships in open seas. In order to achieve this aim we need to know the characteristics of each component of the system and also to know the characteristics of disturbance to ship dynamcis. In this paper we provide calculation method of irregular disturbance to ships in autopilot navigation in open seas and also show calculation examples about two kinds of ship ore carrier and fishing boat. The disturbance consists of irregular wave and random wind, The disturbance is calculated as equivalent yaw angular velocity. Each spectrum and time history of disturbance are reasonably evaluated. Further investigation concerning to performance index of autopilot system and energy loss related to automatic course keeping will be dealt with in another paper,

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Complete Coverage Path Planning for Multi-Robots (멀티로봇에 대한 전체영역 경로계획)

  • Nam, Sang-Hyun;Shin, Ik-Sang;Kim, Jae-Jun;Lee, Soon-Geul
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.7
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    • pp.73-80
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    • 2009
  • This paper describes a path planning algorithm, which is the minimal turning path based on the shape and size of the cell to clean up the whole area with two cleaning robots. Our method divides the whole cleaning area with each cell by cellular decomposition, and then provides some path plans among of the robots to reduce the rate of energy consumption and cleaning time of it. In addition we suggest how to plan between the robots especially when they are cleaning in the same cell. Finally simulation results demonstrate the effectiveness of the algorithm in an unknown area with multiple robots. And then we compare the performance index of two algorithms such as total of turn, total of time.

DYNAMIC AUTOCORRELATION TEMPERATURE MODELS FOR PRICING THE WEATHER DERIVATIVES IN KOREA

  • Choi, H.W;Chung, S.K
    • Journal of applied mathematics & informatics
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    • v.9 no.2
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    • pp.771-785
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    • 2002
  • Many industries like energy, utilities, ice cream and leisure sports are closely related to the weather. In order to hedge weather related risks, they invest their assets with portfolios like option, coupons, future, and other weather derivatives. Among weather related derivatives, CDD and HDD index options are mainly transacted between companies. In this paper, the autocorrelation system of temperature will be checked for several cities in Korea and the parameter estimation will be carried based on the maximum likelihood estimation. Since the log likelihood increase as the number of parameters increases, we adopt the Schwarz information criterion .

The Study of Measurement Method for an electrodeless lamp (무전극 램프의 광특성 측정방식에 대한 고찰)

  • Lee, Se-Hyun;Cho, Mee-Ryoung;Shin, Sang-Wuk;Hwang, Myung-Keun
    • Proceedings of the KIEE Conference
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    • 2003.10a
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    • pp.68-71
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    • 2003
  • In this paper, We have investigated the luminous flux, luminous efficacy, spectral energy distribution, colour rendering index, correlated colour temperature of electrodeless QL lamp system as a center method of measurement and side method of measurement. A result of measurement is that center method of measurement and side method of measurement is almost similar. Therefore, Sample that didn't measured because of big size and heavy weight can be measured by center method of measurement.

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Probabilistic Arrival Power Evaluation considering Voltage Stability (전압안정도를 고려한 확률론적 도달전력 산정에 관한 연구)

  • Moon, Seung-Pil;Chang, Byung-Hoon;Lee, Jae-Gul;Choi, Jae-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.8
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    • pp.1366-1373
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    • 2010
  • Purpose of the electric power system planning and operation is to supply the electric energy to customers continuously and economically. With the mutual exclusive laws of nature between reliability and economic, finding the meeting point is very important but not easy. Commonly the probabilistic reliability indices of the electric power systems are represented with negatively. And the effectiveness of FACTS on the probabilistic reliability could not be reflected with common methods. In this paper, a method to evaluate the probabilistic arrival power at each load point is presented. With this new proposed method, probabilistic reserve margin at load points can be calculated and which can be used with positive reliability index also. Using the P-V analysis, the voltage stability is considered in reliability evaluation. It is expected that the proposed method will be useful expecially in reliability evaluation of electric power system which has voltage restriction.

Density functional study of silanization of the silica surface (실리카 표면의 실란화에 대한 범밀도 함수 계산)

  • Kang, Jee-Won;Lee, Yoon-Sup
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.521-526
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    • 2007
  • Density functional calculations have been performed for the reactions of perfluoroalkylsilane and alkylsilane with silica surfaces. The (100) and (111) surfaces of ${\beta}-cristobalite$ are used as two possible models of the hydroxylated amorphous silica surface. This is the crystalline phase of silica with density and refractive index closest to those of amorphous silica. Moreover, two ${\beta}-cristobalite$ surfaces have the two types of silanol groups, namely the single silanols and the geminal silanols. We investigate the possible adsorption structure and formation energy of perfluoroalkylsilane and alkylsilane molecules with two type of silanol groups. The results will be compared with cluster and slab model.

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