• Animal Systematics, Evolution and Diversity
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• 제32권2호
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• pp.105-111
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• 2016

The genetic structure of marine animals that inhabit the seashore is affected by numerous factors. Of these, gene flow and natural selection during recruitment have strong influences on the genetic structure of seashore-dwelling species that have larval periods. Relative contributions of these two factors to the genetic structure of marine species would be determined mainly by the duration of larval stage. The relationship between larval period and genetic structure of population has been rarely studied in Korea. In this study, genetic variations of cytochrome oxidase subunit I (COI) were analyzed in two dominant species on rocky shore habitats in the Korean peninsula: periwinkle Littorina brevicula and acorn barnacle Fistulobalanus albicostatus. Both species are not strongly structured and may have experienced recent population expansion. Unlike periwinkle, however, barnacle populations have considerable genetic variation, and show a bimodal pattern of mismatch distribution. These results suggest that barnacle populations are more affected by local adaptation rather than gene flow via larval migration. The bimodal patterns of barnacle populations observed in mismatch distribution plots imply that they may have experienced secondary contact. Further studies on seashore-dwelling species are expected to be useful in understanding the evolution of the coastal ecosystem around Korean waters.

• 산업경영시스템학회지
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• 제23권60호
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• pp.37-46
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• 2000

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity This study deals with quasi-static movement to investigate dynamic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performed the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion was developed for muscular load sharing developed. For exertion levels, the transition point of type F motor unit of each muscle is inferred by analyzing the electromyogram at the seated postures. Also, for predetermined seated foot operations exertion levels, the recruitment pattern is identified in the continuous exertion, by analyzing the electromyogram changes due to the accumulated muscle fatigue.

• 산업융합연구
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• 제15권2호
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• pp.1-6
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• 2017

본 논문은 알고리즘을 활용한 최적화를 바탕으로 한 시스템 다이내믹스 피드백 모델을 통해 고용 시뮬레이션의 특징을 제시하는 목적을 가지고 있고 직위, 근무기간, 계급 등의 요소를 중심으로 적정한 고용 인원을 제시하는 3차원 논리적 판단구조를 제공한다. 호주 육군의 고용정책에 대해 보다 신축적인 고용시스템을 제시할 목적으로 시스템 다이내믹스 모델을 통해 국방부의 변화가 심한 정책에 대한 안정적 고용 적정선을 파악한다. 특히 생산성을 최대로 발휘할 수 있는 필요한 고용 패턴 및 외부 인력의 고용, 내부인력의 타 조직으로 이동 등 다양한 가능성을 분석한다.

• 한국전문물리치료학회지
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• 제2권2호
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• pp.1-8
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• 1995

이 논문의 주목적은 정상인을 대상으로 각기 다른 3가지의 (체중의 1.5 %, 3.0 %, 9.0 %) 부하를 통해서 자세의 불균형을 유발시켰을 때 나타나는 postural movement patterns을 기술하기 위한 연구이다. 연구대상의 허리중심에 체중부하를 주어 균형이 뒤로 이동하게 하여, surface EMG(표면 근전도)를 통하여 Tibialis anterior(Ta), Gastrocnernius(Gc), Quadriceps femoris(Qc), Hamstring(Ha), Rectus abdominalis(Ab)와 Paraspinalis(Pa) 근육들의 motor recruitment pattern(운동회집형태)를 측정하였다. 그리고 비디오 촬영은 고관절, 슬관절, 족관절의 움직임을 보기 위해 사용하였다. 특히 근전도 (EMG)는 자세반응 검사에 있어 첫 근반응(근수축) 경과시간(FR)과 분절간격간의 (ID)시간을 조사하는데 사용되었다. 이 연구의 결과는 4가지 중요한 사실을 전해주고 있다. 첫 번째로서, 연구대상자에게 체중의 1.5 %의 부하를 적용하였을 때 Ta가 가장 먼저 수축을 시작하였고(FR:$88{\pm}19.4$ ms) 발목과 대퇴사이의 분절 간격간(ID)의 평균은 +9.3 ms였다. 또한 족관절의 변화가 가장 뚜렷하여 Nashner(1985)의 족기전을 뒷받침하고 있다. 둘째로는 연구대상자에게 체중의 3.0 %의 부하를 주었을 때 Qc와 Ab근육이 원위부에서 근위부 순서로 수축하였고, 첫 번째 근육수축시간은 ($82{\pm}39.2$ ms)였다. 그리고 이때 분절간격의 평균은 +8.3ms 이였고 Ta는 거의 반응하지 않았다. 족관절과 슬관절에 비해 고관절의 변화가 가장 현저하게 나타났고, 이 또한 Nashner의 고관절 기전과 같은 현상을 보였다. 셋째로 연구 대상자에게 체중의 9.0 % 부하를 허리에 적용하였을 때 근수축은 근위부에서 원위부 순서를 이루어졌다. 즉 Ab,Qc, Ta, Ps순으로 근수축 되었다. Ab가 처음으로 수축하여 첫 반응(FR)은 $73{\pm}3.2$ ms 이였고 슬관절과 고관절의 변화가 가장 뚜렷하였다. 넷째로 연구 대상자에게 체중의 9.0 %부하를 적용하였을 때, 균형을 잡기 위해 뒷걸음치는 것이 관찰되었고 이때 근수축 순서는 Ta,Ab.Ps,Qc,Hs였다. 이 결과는 Nasher의 결과와 불일치하였다. 이상과 같은 결과에서 연구대상자의 자세운동형태(postural movement patterns)는 각기 다른 부하 정도와 시간에 따라 합성적으로 이루어지는 것으로 보여졌다. 특히, 자세운동형태는 부하의 적용위치와 연구대상자의 최근의 경험에 영향을 받은 것으로 밝혀졌다. 결론적으로 말하면 자세운동형태는 중앙신경계의 제한적(한정적) 명령 시스템에 의해서 움직임(movement)이 발생하기 전에 조직된다는 Nashner의 가설을 뒷받침하였다.

• 한국자원식물학회지
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• 제11권3호
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• pp.345-352
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• 1998

A Korean endemic and evergreen small tree ' Dendropanax morbifera $L_{EV}$.(Araliaceae)' is a component of evergreen forest and mainly idstributein sourthern region and islands in Korea. A local population of D. morbifera which is located between evergreen and deciduous forest within 50m x 50m quadrate was investigated to ascertain the change of population structure, emergence and growth dynamics of seedlings and saplings, and pattern of spatial distribution by the temproal and spatial expansion of population . The result of analysis of population structure by Importnace Value(IV), evergreen forest showed a high species diversity of evergreen tree species such as Cinnamomum japonicum, Machilus japonica, Neolitsea serica, Daphniphyllum macropodum, Ligustrum japonicum, and etc, in middle and under story than in upper story where Camelia japonica and Quercus acuta were dominant. And in conterminous deciduous fores, the major component of evergreen forest in this region, Camellia japonica, Quercus acuta, evergreen tree of Lauraceae and etc. were abundant in only under story. IV of D. morbifera differed from among three story. In comparative analysis of emergence and growth dynamics of D. morbifera seedlings and saplings between evergreen and deciduous forest, emergece and density of seedlings were significantly greater in evergreen than in deciduous forest, and growth of height and basal diameter of seedlings and saplings were slightly larger in evergreen than in deciduous forest. The spatial distribution patterns by Moristia's index mapping of indivuduals using a lattice method of XY axis within this population showed that seedlings(age up to 2 years) and saplings (age>2 years and height<1m) both evergreen and deciduous forest were more or less aggregated apart from mature trees, and thougth intermediate trees(height>1m and dbh<10cm) had a aggregated distribution pattern, mature trees(dbh>10cm were uniform. In conclusion , the expansion of D. morbfera population from evergreen to deciduous forest accompanied with a mumber of evergreen woody species, and also, emergence and recruitment, and growth of seedlings were greatly influenced moisture and canopy by around community structure.

• 한국패류학회지
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• 제29권4호
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• pp.313-323
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• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• 환경생물
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• 제30권1호
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• pp.71-76
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• 2012

Spills of $M/V$ Hebei Spirit on $7^{th}$ December 2007 caused a seriously damage to the ecosystem of Korean coast. Of these, microbial communities (i.e., attached benthic micro-algae) were reported to be sentive to the environmental change so it can be used for ecological risk assessment. Our experiment was designed to examine the ecological risk assessments for oil pollutant using benthic attached algal community on the artificial substrates of acrylic plates. Field monitoring in the culture system was conducted in Jangmok Bay. The abundances of attached micro-algae on artificial substrates gradually increased with increasing of sampling times. Among them, diatoms were the most important colonizer of coastal water, with the genera $Cylindrotheca$ and $Navicular$ most abundant. In particular, developed the culture system has correctly measured qualitative and quantitative abundance of attached micro-algae because same acrylic plates as artificial substrates were used. Thus, this culture system may be directly applied to the ecological risk experiments of microbial community structure from oil pollutants.

• 해양환경안전학회지
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• 제6권2호
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• pp.1-15
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• 2000

In world trade, the vessel traffic in major routes has been congested due to the rapid increase of cargoes and shipping tonnages. The patterns of vessel traffic have also been complicated and diversified. Therefore it was necessary that the Vessel Traffic Service(VTS) should be established in order to enhance the safety of navigation, to prevent the loss of life and damage to the environment. The first advanced radar surveillance system(LevelIII-VTS) was introduced in Pohang, Korea in 1993 and in 13 other ports later. While the hardware of Korea VTS is equal to that of an advanced country, the software, specially the operation manual, the recruitment and education of VTS operator, and the VTS service area is behind that of Russia, USA, Germany, Hong Kong, Singapore and others. After researching and investigating. the VTS equipment and service area of many countries, and analyzing the IMO regulations relevant to VTS and the traffic pattern and accident of Pohang port, the most efficient VTS service area should be established in Pohang. According to the analysis of the preceding studies and research on VTS, the worldwide VTS areas are recognized under the following conditions: First, the service area should be extended over at least radar coverage taking into account of traffic flow, traffic density, the degree of danger to navigation and harbour condition in order to provide all possible services. Second, the established service area should be subdivided and systematized to render reliable VTS services, such as the allocation of VHF frequency and reporting procedure in each area. In conclusion, the VTS service area of Pohang must be established and operated over 10 miles from shore(radar site) covering the radar coverage, so as to include the area of traffic congestion and high density traffic flow.

• 한국수산과학회지
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• 제19권5호
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• pp.509-517
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• 1986

한실포 잘피밭에 서식하는 어류의 종조성과 출현량의 계절적 변동을 파악하기 위해 1985년 2월부터 1986년 1월까지 1년간 매달 어류를 조사한 결과는 다음과 같다. 1. 조사 기간동안 19과 35종에 속하는 총 4,646마리의 어류가 채집되었으며, 이들은 대부분 10cm이하의 소형 어류였다. 2. Pholis taczanowskii, Pseudoblennius cottoides, Tridentiger trigonecephalus 및 Syngnathus schlegeli의 4어종이 가장 많이 채집되었으며, 채집된 총 개체수의 약 $64\%$를 차지하였다. 3. Sebastes inermis, Platycephalus indius 및 Limanda yokohamae 등과 같은 상업성 어종의 어린치어들도 잘피밭에서 채집되었다. 4. 종조성과 출현량의 계절적 변동은 잘피밭을 이용하는 어류 군집의 특징이었다. 어류의 최대 출현량은 4월과 10월에 나타났으면, 겨울에는 상당히 낮은 출현량을 보였다. 주요 어종은 각자 독특한 출현량의 계절적 변동 양상을 보였는데, 일반적으로 한 어종의 최대 출현량이 나타나는 시기와 다른 어종의 최대 출현량이 나타나는 시기는 $1{\sim}3$개월 정도 분리되어 있었다.

• Journal of Ecology and Environment
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• 제31권4호
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• pp.333-339
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• 2008

We investigated death rates, growth rates and recruitment of culms in two neighboring bamboo (Phyllostachys bamboosoides) stands nested in by two different bird species to analyze stand structure and to design conservation strategies. A third bamboo grove not used by birds, the Taewha stand, was included as a control stand. The bamboo stand occupied by birds in the family Ardeidae (the Ardeidae stand) had an approximately 1.5 times higher culm density than the stand occupied by birds in the family Corvidae (the Corvidae stand). The crude death rate and the number of newly emerged shoots were also higher in the Ardeidae stand than the Corvidae stand. The death rate for bamboo in the Ardeidae stand was not dependent on diameter at breast height (DBH) and was almost 40% for culms of all sizes, whereas most dead culms in the Corvidae stand were < 4 cm DBH. Consequently, we conclude that in the Ardeidae stand, density-independent causes of death are operating, while density-dependent factor are more important in the Corvidae site. The results of soil analysis in these stands suggest that the density-independent death pattern observed in the Ardeidae stand may be due to soil acidification resulting from wastes produced by the birds during breeding. On the other hand, the culm distribution and death patterns in the Corvidae stand suggest that the stand characteristics were not affected by the nesting birds. These results suggest that different conservation strategies must be applied to conserve bamboo groves used by ardeids and corvids for nesting.