• Title/Summary/Keyword: occurrence period

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Characteristics of Marine Environment and Algal Blooms in the Inner Bays of the Korean South Coast (한국 남해안 내만의 해양환경과 적조발생의 특징)

  • Lee, Moon-Ock;Kim, Pyeong-Joo;Kwon, Yeong-Ah
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.469-472
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    • 2006
  • The primary objective of this study was to gain insight into the characteristics of algal blooms in relation to the marine environment of the Korean Southern Coast, using more than 22 years worth of data since the first known occurrence of algal blooms. Algal blooms tend to occur when the precipitation or water temperature for a ten-day period prior to the annual bloom exceeds the long-term mean value. There are three notable causative species in six different inner bays, namely Prorocentrum sp., Skeletonema costatum, and Heterosigma akashiwo, and in addition, these three species appeared in different conditions of water temperature and salinity at each region.

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Seasonal Change in the Reproductive Pattern of the Marine Cladoceran Podon polyphemoides in Korean Waters

  • YOO Kwang-Il;KIM Se-Wha
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.2
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    • pp.141-144
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    • 1990
  • Seasonal change in the reproductive pattern of the marine Cladoceran Podon polyphemoides, was studied using materials collected monthly during the period from January to December 1986 in Yongil Bay, Korea. The relative abundance of P. polyphemoides exceeded $10\%$ of total zooplankton in July. While the species remained as a minor components of the zooplankton community during the other periods of occurrence from June to December. Occurrence of sexual individuals of P. polyphemoides (males and gamogenetic females) in higher proportion in cold months ($30\%$ in November and $40\%$ in December) suggests that resting egg production of this species is largely confined to cold monthis in Korean waters as an overwintering strategy.

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Hydrographic Model Test on Prevention against Vortex Occurrence for Vertical Bulb Turbine

  • Yamato, Shoichi;Nakamura, Shogo;Furukawa, Akinori
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.4
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    • pp.418-425
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    • 2009
  • A vertical bulb turbine unit with elbow type draft tube has been developed due to avoidance of complicated assembling and long standstill period at overhaul in comparison with conventional horizontal bulb turbine unit. Before designing the prototype vertical bulb unit, a hydrographic model test was carried out to establish the ideal design concept for this innovative generating unit. Froude similarity is not available for vortex occurrence. Consequently, an intake structure without air entraining vortices under all the flow conditions is developed, and it is confirmed that the surge wave at load rejection is not affected harmful influence for other constructions.

A Study on Movement Characteristics Analysis of Debris Accumulation at Flood (홍수시 유송잡물 이동 특성 분석에 관한 연구)

  • Oh, Chae-Yeon;Jun, Kye-Won;Yoon, Young-Ho
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.707-710
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    • 2008
  • Recently, a rivers' bridge that locate on among the mountains area is destroyed by debris accumulation and debris flow, because of frequent occurrence of typhoon and a localized torrential downpour. therefore a river make a part of dam's effect. Actually, this situation gives damages like inundation of a bridge upper stream area's. Generally, It the main cause of the occurrence route of the debris accumulation is that outbreaks of driftwood and debris flow because of landslide, that occurred by severe rain storm. Also, a lot of debris are occurred when big flood come up during long period at this time, this kind of debris accumulation remove to other place, in several, and specially, debris accumlation move to the place where the depth of water is deep and velocity is fast river center. According to these kind of fact, this research put in effect and analyze that movement characteristic's numerical simulations of debris accumulation at flood according to a domestic outside literature investigation, on-site monitoring survey and parameter scenario which comes out through the hydraulic modeling analysis.

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Seasonal Occurrence and Development of Gray Blight of Tea Plants in Korea

  • Koh, Young-Jin;Shin, Gil-Ho;Hur, Jae-Seoun
    • The Plant Pathology Journal
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    • v.17 no.1
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    • pp.40-44
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    • 2001
  • Disease occurrence and development of gray blight of tea (Camellia sinensis) were investigated. Higher incidences and more severe damage by gray blight were found in Japanese tea variety Yabukita than the Korean local variety. In Yabukita, Pestalotiopsis longiseta was more frequently observed on the diseased leaves than P. theae but vice versa in the Korean local variety. This indicates that there was the varietal difference in the distribution of fungal species of gray blight pathogens. Both varieties were most severely damaged during the third harvest period with weather conditions of high temperature and humidity favorable to the disease. Presence of the tea brown blight fungus Glomerella cingulata on the margin of gray blight lesion at the late stahe suggested that the pathogenic fungi of tea gray blight were replaced by the brown blight fungus during the disease development.

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Minimum loading requirements for areas of low seismicity

  • Lam, Nelson T.K.;Tsang, Hing-Ho;Lumantarna, Elisa;Wilson, John L.
    • Earthquakes and Structures
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    • v.11 no.4
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    • pp.539-561
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    • 2016
  • The rate of occurrence of intraplate earthquake events has been surveyed around the globe to ascertain the average level of intraplate seismic activities on land. Elastic response spectra corresponding to various levels of averaged (uniform) seismicity for a return period of 2475 years have then been derived along with modifying factors that can be used to infer ground motion and spectral response parameters for other return period values. Estimates derived from the assumption of uniform seismicity are intended to identify the minimum level of design seismic hazard in intraplate regions. The probabilistic seismic hazard assessment presented in the paper involved the use of ground motion models that have been developed for regions of different tectonic and crustal classifications. The proposed minimum earthquake loading model is illustrated by the case study of Peninsular Malaysia which has been identified with a minimum effective peak ground acceleration (EPGA) of 0.1 g for a return period of 2475 years, or 0.07 g for a notional return period of 475 years.

Changing Transmission Pattern of Plasmodium vivax Malaria in the Republic of Korea: Relationship with Climate Change

  • Park, Jae-Won
    • Environmental Analysis Health and Toxicology
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    • v.26
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    • pp.1.1-1.6
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    • 2011
  • Plasmodium vivax malaria has occurred annually in the Republic of Korea (ROK) since its re-emergence in 1993. P. vivax malaria in ROK has been strongly influenced by infected mosquitoes originating from the Democratic People's Republic of Korea. Korean P. vivax malaria has shown typical characteristics of unstable malaria transmitted only during the summer season, and displays short and long incubation periods. The changing pattern of the transmission period can be predicted by analyzing the seasonal characteristics of early primary attack cases with a short incubation period. Such cases began to gradually occur earlier in the 1990s after the re-emergence. Most of the malaria cases after mid-August are presumed to be early primary attack, short incubation period cases. Only primary transmission was possible until the early 2000s, whereas up to fourth or fifth transmission occurred in the mid-2000s. The results indicate that the length of transmission period has been gradually extending, which may be ascribed to a climate change-mediated temperature rise. Malaria and climate data should be integrated to analyze and predict the influence of climate change on malaria occurrence in ROK.

A Study on Calculation Method of Compensation for Indirect Damage of Fishery by Undertaking Public Project (공익사업시행(公益事業施行)으로 인한 어업(漁業)의 간접피해(間接被害) 보상액(補償額) 산출방법(算出方法)에 관(關)한 연구(硏究))

  • Kim Ki-Dae;Kim Byung-Ho
    • The Journal of Fisheries Business Administration
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    • v.37 no.1 s.70
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    • pp.25-44
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    • 2006
  • Under the provision of Article 63 of the Enforcement Regulation of the Act on Acquisition and Compensation of Land and Others for Public Project that is recently enacted and implemented (hereinafter referred to as the 'Lend Compensation Act') the compensation is required to make 'When the Actual Damage Amount' is confirmed for the damage in fishery affairs that is outside of the public project area. The compensation for fishery business on the indirect damage area has been excluded from the advance compensation subject to conflict with the existing laws on fishery business compensation with the controversy in method, procedure, time and others to confirm the actual damage amount, and it lacks the standard of calculation for detailed compensation on partial damages outside of business implementation area, which caused the ceaseless conflicts and straggles between the project implementation party and the victimized fishermen regarding the calculation method of damages, standard, compensation period and others. In particular, from the numerous problems in damage compensation in fishery on the indirect damage area, the most recent problem emerged is the issue on application method of damage period in calculating the damage compensation amount that the struggle has been deepened with the differences between the project implementation party and the victimized fishermen without the stipulation on the compensation, that caused the difficulties in carrying out the public project and other serious social problems. In this study, the reasonable application method for the damage period and the calculation plan of the damage amount for calculating the damages on fishery industry outside of the public project implementation zone that is not fully specified under the Land Compensation Act, and the indirect damage area is not influenced for the notification of project recognition, and the compensation to undertake with the damage in the fishery industry in project implementation area to have the nature of damage compensation, the right to engage in fishery industry has the perpetual nature of rights, the fishery damage compensation system of Japan also recognizes the perpetual right on fishery industry to calculate the compensation amount, and the compensation for damage amount has been exercised for the period of actual damage occurrence period regardless of remaining effective period for most of fishery permit and license for fishery compensation outside of the project implementation area following the recent various public projects as well as the development process of theory on fishery loss compensation that the calculation of damage amount on the fishery industry outside of the project implementation zone would be prudent to compensate by calculating the applicable damages during the period of actual damages, and by doing so, the 'just compensation' guaranteed under the Constitution may be materialized. Therefore, the calculation of the damages from the implementation of the public project shall consider the actual period of damages and the degree of damage from the public project to calculate by the income capitalization method, however, considering the equitable consideration with the compensation following the cancellation, it shall not exceed the compensation following the termination of the applicable fishery businesses. Furthermore, the calculation method of partial damage amount on the fishery business following the project implementation shall apply, depending on the period of damage occurrence, by (1) the case of calculating the future damage amount at the present time, and (2) calculating the damage from the past to the present time as well as the damage to be incurred later, by selecting the calculation method for damages following the damage occurrence type.

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The Vegetational and Environmental History of the Pre-Holocene Period in the Korean Peninsula (한반도 식생 및 환경변천사(홀로세 이전 시대를 중심으로))

  • Kong, Woo-Seok
    • The Korean Journal of Quaternary Research
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    • v.6 no.1
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    • pp.1-11
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    • 1992
  • The reconstruction of the vegetational and environmental history of the Korean peninsula by the use of various fossil floral data from the Carboniferous period to the Pre-Holocene is reviewed. Though the oldest plant fossil in Korea (Neuropteris) dates back to the Carboniferous period, the first appearance of many of the present-day floristic genera indeed dates back to the Oligocene (c. 40 to 20 million years B.P.), and includes many thermophilous genera. The presence of thermophilous genera in the Oligocene at up to four degrees north of their present distributional limits implies that the climate of the Oligocene was warmer than that of today. The occurrence of similar thermophilous floristic element at up to six degrees north of their present range during the Middle Miocene suggests a maximum northward expansion of warmth-loving evergreen broadleaved vegetation for, recent Korean vegetation history. The continued occurrence of numerous present-day genera since the Oligocene period indicates a long-term stability of Korean vegetation, along with minor fluctuations within it. The admixture of evergreen coniferous plants and deciduous breadleaved plants, however, indicates a probable temperate climate for much of the Middle Pleistocene. There are couple of evidences which are indicative of an early-stage anthropogenic disturbance of natural vegetation during the Middle Pleistocene of Korea. The presence of cold-episodes during the Upper Pleistocene caused a general expansion of deciduous plants and cryophilous evergreen coniferous, plants. It is likely that the maximum southward expansion of cryophilous arctic-alpine and alpine floras in Korea occured during the penultimate glacial period. The disappearance of some cryophilous genera from 10,000 years B.P. marks the continued climatic amelioration since then, along with minor climatic fluctuations during the Holocene period.

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An Analysis of Accidents in the Expressway Structure Construction (고속도로 구조물공사의 안전사고 특성분석)

  • Huh, Woon-Chan;Kim, Young-Ai;Hwang, Uk-Sun;Kim, Yong-Su
    • Korean Journal of Construction Engineering and Management
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    • v.11 no.3
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    • pp.97-104
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    • 2010
  • The expressway construction work is being recently diversified even the working environments and the working kinds due to getting large scale, complexity, and high technology. The accidents are increasing according to large scale even in construction equipment and to a rise in high-ground work, thereby being required an effort of reducing accidents. However, it is insufficient in a means of coping with the technically safety management of using specific and scientific method. In order to prevent accident, a specific plan is needed that can apply each in variables to safety management by analyzing the accident types and accident factors with statistical method. Accordingly, this study carried out investigate on accidents for 12 years in the expressway construction work, and aimed to analyze characteristics on the accident type and conversion disaster-victim number according to factors with occurrence of accidents. Thus, the empirical analysis was performed. As a result of research, first, as a result of verifying significant difference with accident type by accident factor, the significant difference was shown between a cause for occurrence of accident and height with occurrence of accident. Second, among factors by period, the time with occurrence of accident was indicated to have significant difference from conversion disaster-victim number. Among factors by work condition, the cause for occurrence of accident, the height with occurrence of accident, and the type with occurrence of accident were indicated to have significant difference from conversion disaster-victim number. What suggested by analyzing characteristics in these factors and variables has important significance as a countermeasure for safety management.