• Title/Summary/Keyword: Range dependent environment

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Projection of climate change effects on the potential distribution of Abeliophyllum distichum in Korea (기후변화에 따른 우리나라 미선나무의 분포변화 예측)

  • Lee, Sang-Hyuk;Choi, Jae-Yong;Lee, You-Mi
    • Korean Journal of Agricultural Science
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    • v.38 no.2
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    • pp.219-225
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    • 2011
  • Changes in biota, species distribution range shift and catastrophic climate influence due to recent global warming have been observed during the last century. Since global warming affects various sectors, such as agriculture and vegetation, it is important to predict more accurate impact of future climate change. The purpose of this study is to examine the observed distribution of Abeliophyllum distichum in the Korean peninsula. For this purpose, two period (present and future) climate data were used. Mean data between 1950 and 2000, were used as the present value and the year 2050 and 2080 data from A1B senario in IPCC SRES were used for the future value. Potential habitation is analyzed by MaxEnt(Maximum Entropy model), and Abeliophyllum distichum's coordinates data were used as a dependent variable and independent variables are composed of environmental data such as BioClim, altitude, aspect and slope. The result of six types GCM mean calculation, the potential habitability decreased by 40-60% of the average existing distribution. The methodogies and results of this research can be applicable to the climate changing adaptation stratiegies for the biodiversity conservation.

Comparative Study on Mechanical Behavior of Low Temperature Characteristics of Polymeric Foams for Ships and Offshore Structures (폴리머 폼의 선박 및 해양구조물 적용을 위한 극저온 기계적 거동 특성 분석)

  • Park, Seong-Bo;Kim, Jeong-Hyeon;Lee, Jae-Myung
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.6
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    • pp.495-502
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    • 2014
  • Glass-reinforced polyurethane foam (R-PUF) is widely used as the primary and secondary insulation of Mark-III type liquefied natural gas (LNG) cargo system. And, polyurethane foam (PUF) and polyisocyanurate foam (PIR) are often used for insulation of onshore structures or LNG storage and pipeline system. These polymeric foam materials are known for the characteristics that mechanical properties are dependent on strain rate and temperature. In this study, compression tests for R-PUF, PIR, and PUF were carried out for the estimation of mechanical behaviors under the cryogenic environment. The range of thermal condition was from room temperature to 110K and strain rates were $10^{-3}s^{-1}$ and $10^{-4}s^{-1}$. The test results were analyzed based on the conditions of strain-rate and temperature.

Genetic Variability of Show Jumping Attributes in Young Horses Commencing Competing

  • Prochniak, Tomasz;Rozempolska-Rucinska, Iwona;Zieba, Grzegorz;Lukaszewicz, Marek
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.8
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    • pp.1090-1094
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    • 2015
  • The aim of the study was to select traits that may constitute a prospective criterion for breeding value prediction of young horses. The results of 1,232 starts of 894 four-, five-, six-, and seven-year-old horses, obtained during jumping championships for young horses which had not been evaluated in, alternative to championships, training centres were analyed. Nine traits were chosen of those recorded: ranking in the championship, elimination (y/n), conformation, rating of style on day one, two, and three, and penalty points on day one, two, and three of a championship. (Co)variance components were estimated via the Gibbs sampling procedure and adequate (co)variance component ratios were calculated. Statistical classifications were trait dependent but all fitted random additive genetic and permanent environment effects. It was found that such characteristics as penalty points and jumping style are potential indicators of jumping ability, and the genetic variability of the traits was within the range of 14% to 27%. Given the low genetic correlations between the conformation and other results achieved on the parkour, the relevance of assessment of conformation in four-years-old horses has been questioned.

(An) experimental study on the development of lightweight concrete using the PCM (PCM 혼입 경량기포콘크리트 패널 개발을 위한 기초적 연구)

  • Lim, Myung Kwan;Enkhbold, Odontuya;Kim, Young Ho;Choi, Dong Uk
    • KIEAE Journal
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    • v.14 no.4
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    • pp.133-138
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    • 2014
  • The present study was carried out to assess the basic material properties and thermal behavior of light-weight foamed concrete panel mixed with PCM (Phase Changing Material). To do so, this study fabricated light-weight foamed concrete (1.0kg/m3) in pre-foaming method and mixed it with PCM micro capsule of 1-dodecanol and melamine to examine its physical and thermal properties. The results confirmed strength reinforcement effect by proper replacement ratio of fly-ash, which is an industrial by-product, and PCM. In addition, it found out that PCM-mixed light-weight foamed concrete had time delay and temperature reduction effect within the range of PCM phase transition according to the rise of outdoor temperature. It was also observed that the insulation performance of PCM-mixed light-weight foamed concrete was more dependent upon thickness than PCM replacement ratio.

Droplet Vaporization in High Pressure Environments with Pressure Oscillations (강한 압력 교란에 구속된 고압 액적의 천이 기화)

  • 김성엽;윤웅섭
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.157-163
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    • 2003
  • A systematic numerical experiment has been conducted to study droplet gasification in high pressure environments with pressure oscillations. The general frame of previous rigorous model[1] is retained but tailored for flash equilibrium calculation of vapor-liquid interfacial thermodynamics. Time-dependent conservation equations of mass, momentum, energy, and species concentrations are formulated in axisymmetric coordinate system for both the droplet interior and ambient gases. In addition, a unified property evaluation scheme based on the fundamental equation of state and empirical methods are used to find fluid thermophysical properties over the entire thermodynamic domain of interest. The governing equations with appropriate physical boundary conditions are numerically time integrated using an implicit finite-difference method with a dual time-stepping technique. A series of calculation have been carried out to investigate the gasification of an isolated n-pentane droplet in a nitrogen gas environment over a wide range of ambient pressures and frequencies. Results show that the mean pressures and frequencies of the ambient gas have strong influences on the characteristics of the droplet gasification. The amplitude of the response increases with increasing pressure, and the magnitude of the vaporization response increases with the frequency.

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Underwater Acoustic Environment and Low Frequency Acoustic Transmission in the Sub-Polar Front Region of the East Sea (동해 아극전선 해역의 수중음향환경 및 저주파 음파전달 양상)

  • Lim, Se-Han;Ryu, Gun-Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.4
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    • pp.415-423
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    • 2009
  • To investigate low frequency acoustic transmissions in the Sub-Polar Front(SPF) of the East Sea, numerical experiments are conducted with Range dependent Acoustic Model(RAM) using Circulation Research of the East Asian Marginal Seas(CREAMS) data and Autonomous Profiling Explorer(APEX)) data. Significant seasonal variations of sea water properties are existed across the Sub-Polar Front(SPF) region from the north and the south. The model results show that Transmission Loss(TL) decrease(about 20dB) with ideal front in the warm region whereas TL increase(about 25dB) with ideal front in the cold region. Regardless of season(both in summer and winter), when the sound source is located in the cold region of the SPF, the model results show weak TL, compared to the case of the source in the warm region(Maximum difference of TL reaches 28dB). This difference between the cases when the source is located in the cold region and the warm region, is accounted for from the different vertical profiles of sound speed in both regions.

Implementation of Multi-functional Type Condition Monitoring System for Railway Catenary Systems (전기철도 전차선로의 설치 상태 판단을 위한 복합검측 기술 구현)

  • Park, Young;Lee, Kiwon;Park, Shin Young;Park, June Young;Choi, Won Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.9
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    • pp.1406-1410
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    • 2015
  • The railway catenary systems consist of a complex structure, electrical and mechanical conditions are exposed to dangerous environment due to current collection between pantograph and catenary systems. These two types of conditions for the catenary systems are critically assessed for management and are becoming increasingly more dependent on reliable inspection system. In this paper, a new measurement system which enables inspection of catenary faults was studied and implemented. The system uses wavelength band of ultraviolet (UV) and IR (Infrared) to measure the insulation of corona and temperature of catenary wire. In order to determine the sensitivity of implemented system, the performance test such as distance detection range of UV camera and temperature resolution of IR camera were conducted, respectively. The field test of development system was also conducted in metro and high-speed line using mobile type UV and IR multi-composited measurement systems.

On relationship among h value, membership function, and spread in fuzzy linear regression using shape-preserving operations

  • Hong, Dug-Hun
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2008.04a
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    • pp.306-310
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    • 2008
  • Fuzzy regression, a nonparametric method, can be quite useful in estimating the relationships among variables where the available data are very limited and imprecise. It can also serve as a sound methodology that can be applied to a variety of management and engineering problems where variables are interacting in an uncertain, qualitative, and fuzzy way. A close examination of the fuzzy regression algorithm reveals that the resulting possibility distribution of fuzzy parameters, which makes this technique attractive in a fuzzy environment, is dependent upon an h parameter value. The h value, which is between 0 and 1, is referred to as the degree of fit of the estimated fuzzy linear model to the given data, and is subjectively selected by a decision maker (DM) as an input to the model. The selection of a proper value of h is important in fuzzy regression, because it determines the range of the posibility ditributions of the fuzzy parameters. In this paper, we discuss the interdependent relationship among the h value, membership function shape, and the spreads of fuzzy parameters in fuzzy linear regression with fuzzy input-output using shape-preserving operations.

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Relationship Among h Value, Membership Function, and Spread in Fuzzy Linear Regression using Shape-preserving Operations

  • Hong, Dug-Hun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.8 no.4
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    • pp.306-311
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    • 2008
  • Fuzzy regression, a nonparametric method, can be quite useful in estimating the relationships among variables where the available data are very limited and imprecise. It can also serve as a sound methodology that can be applied to a variety of management and engineering problems where variables are interacting in an uncertain, qualitative, and fuzzy way. A close examination of the fuzzy regression algorithm reveals that the resulting possibility distribution of fuzzy parameters, which makes this technique attractive in a fuzzy environment, is dependent upon an h parameter value. The h value, which is between 0 and 1, is referred to as the degree of fit of the estimated fuzzy linear model to the given data, and is subjectively selected by a decision maker (DM) as an input to the model. The selection of a proper value of h is important in fuzzy regression, because it determines the range of the posibility ditributions of the fuzzy parameters. In this paper, we discuss the interdependent relationship among the h value, membership function shape, and the spreads of fuzzy parameters in fuzzy linear regression with fuzzy input-output using shape-preserving operations.

Physical Characteristics of Internal Waves and the Effect of Short Depression Internal Wave on Acoustic Transmission in the East Sea (동해 내부파의 물리적 특성과 단주기 오목형 내부파가 음파전달에 미치는 영향)

  • Han, Bong-Wan;Lim, Se-Han;Park, Kyeong-Ju;Kim, Seong-Il
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.1
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    • pp.37-43
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    • 2009
  • Fluctuations in the ocean are closely related with the underwater acoustic propagation. Internal waves are generated by fluctuation of isopycnal layer in the upper part of the stratified ocean, which are propagated from offshore to coastal area. Physical characteristics of the internal waves existed in the East Sea were derived from the five field experimental data and the ocean monitoring buoy nearshore the mid-east coast of Korea. The dominant periods are appeared in the near-inertial period about $17{\sim}20hours$ and the short period about a few minutes. The wavelengths of them are $10{\sim}50km$ and $300{\sim}1000m$, and the phase speeds are $20{\sim}100cm/s$ and $30{\sim}70cm/s$, respectively The maximum amplitudes are about $20{\sim}25m$. Under the environment of short depression internal wave propagation, the variations of transmission loss field were investigated using an range-dependent acoustic transmission loss model(RAM). The result shows that the large irregular variations of transmission loss caused by progressing the internal wave from offshore toward coast.