• Title/Summary/Keyword: degree distribution

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A Study on Distribution of Vegetation and Assessment of Green Naturality in Naejangsan National Park (내장산국립공원의 식생분포 및 녹지자연도 사정에 관한 연구)

  • Oh, Koo-Kyoon;Kim, Young-Jin
    • Korean Journal of Environment and Ecology
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    • v.25 no.2
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    • pp.166-174
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    • 2011
  • This study was carried out to investigate the actual vegetation and Degree of Green Naturality(DGN) in Naejangsan National Park in 2010. The actual vegetation of the surveyed site were classified into twelve plant communities and the others. Secondary forest were classified into eight plant communities; Pinus densiflora community, Deciduous broadleaf forest, Quercus mongolica community, etc. Afforested lands were classified into four forest types: P. rigida -P. densiflora forest, P. rigida forest, etc. The area of DGN 8 consisted of 60.58% while the area of DGN 9 consisted of 3.62% when compared with land area in Naejangsan National Park. The exotic plants needs to be managed for recovery of natural landscape and biological diversity in Naejangsan National Park.

Forest Structure and Composition in the Vicinity of Srinagar Hydroelectric Power Project in Alaknanda Valley, Garhwal Himalaya, India

  • Ballabha, Radha;Kuniyal, Archana;Tiwari, Prabhawati;Tiwari, Jay Krishan
    • Journal of Forest and Environmental Science
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    • v.36 no.2
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    • pp.78-90
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    • 2020
  • We studied forest structure and composition in the vicinity of Srinagar Hydroelectric Power Project in Alaknanda Valley, Garhwal Himalaya, India to provide baseline data for the management of forests. Eight sites were selected in the vicinity of power project based on elevation and species composition. Density varied from 650 to 340 ind ha-1 for trees and from 4,360 to 6,480 ind ha-1 for shrubs. TBC ranged from 35.02 to 54.02 ㎡ ha-1 for trees and from 0.875 to 2.628 ㎡ ha-1 for shrubs. On the basis of density and IVI, Pinus roxburghii was found dominant tree species in most of the sites, whereas among the shrubs, Carissa opaca was dominant. Dominance of Pinus roxburghii in most of the sites is an indication towards possible threat to associated species in the area. The dominance-diversity curve of trees showed a geometric distribution, whereas the shrubs displayed log-normal curves. The forest has rich and diverse species composition however; habitat degradation caused by the construction of Power Project might lead to reduction of plant species from the area. The information obtained from this study will be helpful in predicting possible changes in the forest ecosystem properties in near future after completion of the power project.

Waveform characterization and energy dissipation of stress wave in sandstone based on modified SHPB tests

  • Cheng, Yun;Song, Zhanping;Jin, Jiefang;Wang, Tong;Yang, Tengtian
    • Geomechanics and Engineering
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    • v.22 no.2
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    • pp.187-196
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    • 2020
  • The changeable stress environment directly affect the propagation law of a stress wave. Stress wave propagation tests in sandstone with different axial stresses were carried using a modified split Hopkinson Pressure bar (SHPB) assuming the sandstone has a uniform pore distribution. Then the waveform and stress wave energy dissipation were analyzed. The results show that the stress wave exhibits the double peak phenomenon. With increasing axial stress, the intensity difference decreases exponentially and experiences first a dramatic decrease and then gentle development. The demarcation stress is σ/σc=30%, indicating that the closer to the incident end, the faster the intensity difference attenuates. Under the same axial stress, the intensity difference decreases linearly with propagation distance and its attenuation intensity factor displays a quadratic function with axial stress. With increasing propagation distance, the time difference decays linearly and its delay coefficient reflects the damage degree. The stress wave energy attenuates exponentially with propagation distance, and the relations between attenuation rate, attenuation coefficient and axial stress can be represented by the quadratic function.

Collaborative Research Network and Scientific Productivity: The Case of Korean Statisticians and Computer Scientists

  • Kwon, Ki-Seok;Kim, Jin-Guk
    • Asian Journal of Innovation and Policy
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    • v.6 no.1
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    • pp.85-93
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    • 2017
  • This paper focuses on the relationship between the characteristics of network and the productivity of scientists, which is rarely examined in previous studies. Utilizing a unique dataset from the Korean Citation Index (KCI), we examine the overall characteristics of the research network (e.g. distribution of nodes, density and mean distance), and analyze whether the network centrality is related to the scientific productivity. According to the results, firstly we have found that the collaborative research network of the Korean academics in the field of statistics and computer science is a scale-free network. Secondly, these research networks show a disciplinary difference. The network of statisticians is denser than that of computer scientists. In addition, computer scientists are located in a fragmented network compared to statisticians. Thirdly, with regard to the relationship between the researchers' network position and scientific productivity, a significant relation and their disciplinary difference have been observed. In particular, the degree centrality is the strongest predictor for the scientists' productivity. Based on these findings, some policy implications are put forward.

An Optimal Die Design for the Coating Uniformity of Non-Newtonian Liquids in Slot Coating Process (Slot 코팅 공정에서 Non-Newtonian 유체의 코팅 균일성을 위한 최적 다이 설계)

  • Lee, Si-Hyung;Koh, Hyun-Jung;Shim, Seo-Hoon;Jung, Hyun-Wook;Hyun, Jae-Chun
    • Korean Chemical Engineering Research
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    • v.49 no.3
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    • pp.314-319
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    • 2011
  • In this study, the flow behavior of Newtonian and non-Newtonian coating liquids inside slot die has been scrutinized for the purpose of optimal internal die design in slot coating system from three-dimensional computations by CFD Fluent solver. A hybrid slot die could be optimally designed by changing the chamber or manifold structure to guarantee the uniform velocity distribution of coating liquids at die exit. Especially, for the non-Newtonian coating liquids, the length of coat-hanger for the uniform coating has been properly chosen, according to the degree of their shearthinning properties.

Effect of a Magnetic Field on the Solute Distribution of Czochralski Single Crystal Growth (초크랄스키 단결정 성장에서 자기장이 용질분포에 미치는 영향)

  • Kim, Moo Gewi;Suh, Jeong Se
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.3
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    • pp.388-397
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    • 1999
  • Numerical simulations are carried out for the magnetic Czochralski single crystal growth system. It Is shown that a magnetic field significantly suppresses the convective flow and as the strength of magnetic field becomes to be stronger, the heat transfer in the melt is dominated by conduction rather than convection. By imposing a cusp magnetic field, the growth interface shape becomes convex toward the melt. When the axial magnetic field is imposed, there occurs an inversion of the interface shape with increase of the magnetic field strength. The oxygen concentration near the interface decreases with increasing cusp magnetic field strength while axial field causes an increase of an oxygen concentration at the central region and decrease of that at the edge of the crystal. The results show that the cusp magnetic field has advantages over an axial magnetic field In the radial uniformity of oxygen as well as in the additional degree of control.

Stochastic cost optimization of ground improvement with prefabricated vertical drains and surcharge preloading

  • Kim, Hyeong-Joo;Lee, Kwang-Hyung;Jamin, Jay C.;Mission, Jose Leo C.
    • Geomechanics and Engineering
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    • v.7 no.5
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    • pp.525-537
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    • 2014
  • The typical design of ground improvement with prefabricated vertical drains (PVD) and surcharge preloading involves a series of deterministic analyses using averaged or mean soil properties for the various combination of the PVD spacing and surcharge preloading height that would meet the criteria for minimum consolidation time and required degree of consolidation. The optimum design combination is then selected in which the total cost of ground improvement is a minimum. Considering the variability and uncertainties of the soil consolidation parameters, as well as considering the effects of soil disturbance (smear zone) and drain resistance in the analysis, this study presents a stochastic cost optimization of ground improvement with PVD and surcharge preloading. Direct Monte Carlo (MC) simulation and importance sampling (IS) technique is used in the stochastic analysis by limiting the sampled random soil parameters within the range from a minimum to maximum value while considering their statistical distribution. The method has been verified in a case study of PVD improved ground with preloading, in which average results of the stochastic analysis showed a good agreement with field monitoring data.

Key Determinants of Repurchase Intention toward Organic Cosmetics

  • NGUYEN, Phuong Ngoc Duy;NGUYEN, Vinh Tan;VO, Nguyen Ngoc Thao
    • The Journal of Asian Finance, Economics and Business
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    • v.6 no.3
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    • pp.205-214
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    • 2019
  • This paper aims to discover factors and their influences degree to repurchase organic cosmetic in Vietnam. In addition, this research also discloses the main segments that have high demand re-buying intention based on demographic groups of gender, age, income, educational level, job, type of products, and place of production. Twenty-eight scale was designed based on previous studies and adjusted to match the 5-point Likert scale to conduct measurement. By using survey method to test hypotheses and set up conceptual models to collect 295 Vietnamese consumers who have experience in consuming organic cosmetic by explain the results through Smart PLS software. The findings show that there is positive attitude of customers to the intention of acquiring organic cosmetics, green perceived and customer satisfaction. In addition, customer satisfaction, knowledge of products, safety values, and environmental protection consciousness also play important roles to form a positive attitude of customers for products. Moreover, the consciousness of green living of consumers accounts for a high proportion in creating customer satisfaction for organic products. The results show useful information for current premises to determine the factors that influence the decision to repurchase organic cosmetic product, that provide business strategies.

Residual Strain Effect on Circumferential Strain on Arterial Cross-Section (동맥 전단부에 분포된 원주 변형율에 대한 잔유 변형율의 영향)

  • 황민철;신정욱
    • Journal of Biomedical Engineering Research
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    • v.16 no.3
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    • pp.325-330
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    • 1995
  • The distribution of circumferential strain of arterial cross-section Is highest at intima and lowest at adventitia. However, the circumferential strain is theoretically severe at Intima because there is strain concentration. The theoretical degree of the intimal strain can not be explained in physiological condition even though artery is physiologically normal. Physiological adaptation may be undertaken to strain concentration. However, it is not clear, yet. Residual strain of artery is eagerly studied. There is experimental evidence that residual strain exists in artery. When ring of artery is longitudinally cut, it is opened. Assumption is made that intimal strain concentration is reduced with the considel'ation of residual strain. This study experimentally attempts to quantify the effect of residual strain on circumferential strain which is determined under the assumption of zero strain with zero pressure.

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Physicochemical and structural properties of lintnerized starches from sweet Potato (고구마전분의 산처리 특성과 산분해 잔사의 구조적 특성)

  • Kim, Sung-Ran;Ahn, Seung-Yo
    • Applied Biological Chemistry
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    • v.35 no.3
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    • pp.196-201
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    • 1992
  • Characteristics on lintnerization of dry type (Suwon 147) and moist type (Hwangmi) sweet potato starches were investigated. Chain distribution of lintnerized starches was also studied by debranching with pullulanase. Hydrolytic patterns of two starches showed two distinct stages and hydrolysis extents of Suwon 147 starch were lower than those of Hwangmi starch. The relative crystallinities of Suwon 147 starches were higher than those of Hwangmi starch. The elution profiles of lintnerized starches were composed of two peaks about degree of polymerization (DP) 25 and DP 15. The elution profiles of debranched samples showed only one peak about DP 15 and peak DP of Suwon 147 lintnerized starch was higher than that of Hwangmi.

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