• Title/Summary/Keyword: foraging

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The Food Resources and Foraging Sites of Pacific Reef Herons(Egretta sacra) in Jeju Island, Korea (제주도에서 흑로 Egretta sacra의 식이물과 취식 영역)

  • Kim, Wan-Byung;Oh, Hong-Shik
    • Korean Journal of Environment and Ecology
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    • v.23 no.6
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    • pp.564-568
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    • 2009
  • The principal objective of this study was to determine and characterize the food resources and foraging sites of Pacific Reef Herons bred in Aewol-eup, Jeju Island, during Feb. 2005 ~ Aug. 2005. The food resources of Pacific Reef Herons were identified as comprising 21 individuals of 5 species, and these identifications were verified as follows: 38.1% of Tridentoger obscurus(n=8), 19.0% of Ennedpterygius etheostomus(n=4), and 14.3% of Engraulis japonica(n=3). The sizes of the food resources were measured as follows: total $58.29{\pm}5.17mm$(n=19), T. obscurus was $67.49{\pm}4.91mm$(n=8), E. etheostomus was $43.98{\pm}3.50mm$(n=4), and E. japonica was $22.77{\pm}1.17mm$. The semi-digested foods were confirmed as Paralichthys olivaceus and Sebastes inermis. The primary foraging sites were 7.4km(Oedocheon) east, to 6.6km(Geumseongcheon) west of the Aewol breeding area.

Effect of Restricted Grazing Time on the Foraging Behavior and Movement of Tan Sheep Grazed on Desert Steppe

  • Chen, Yong;Luo, Hailing;Liu, Xueliang;Wang, Zhenzhen;Zhang, Yuwei;Liu, Kun;Jiao, Lijuan;Chang, Yanfei;Zuo, Zhaoyun
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.5
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    • pp.711-715
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    • 2013
  • To investigate the effect of restricted grazing time on behavior of Tan sheep on desert steppe, forty 4-months old male Tan sheep with an original body weight (BW) of $15.62{\pm}0.33$ kg were randomly allocated to 4 grazing groups which corresponded to 4 different restricted grazing time treatments of 2 h/d (G2), 4 h/d (G4), 8 h/d (G8) and 12 h/d (G12) access to pasture. The restricted grazing times had a significant impact on intake time, resting time, ruminating time, bite rate and movement. As the grazing time decreased, the proportion of time spent on intake, bite rate and grazing velocity significantly (p<0.05) increased, but resting and ruminating time clearly (p<0.05) decreased. The grazing months mainly depicted effect on intake time and grazing velocity. In conclusion, by varying their foraging behavior, Tan sheep could improve grazing efficiency to adapt well to the time-limited grazing circumstance.

Information Forager's Approach to Folksonomy (정보채집으로의 접근 - 폭소노미 이해를 위한 개념적 틀 연구 -)

  • Park, Hee-Jin
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.22 no.3
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    • pp.189-206
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    • 2011
  • This paper proposes a conceptual framework to explore the ways in which people work with in accessing, sharing, and navigating Web resources. In order to provide a better frame of a user's interaction with a folksonomy, an information foraging approach was adapted that denotes adaptive information seeking behaviors of users within human information interaction. A conceptual framework that consists of three different components from users' points of view was proposed: tagging, navigation, and knowledge sharing. This understanding will help us to motivate possible future directions of research in folksonomy and lay the groundwork for empirical research which focuses on qualitative analysis of a folksonomic and users' tagging behaviors.

Effect of Climatic Conditions on Pollination Behavior of Honeybees (Apis mellifera L.) in the Greenhouse Cultivation of Watermelon (Citrullus lanatus L.)

  • Lee, Kyeong Yong;Lim, Jeonghyeon;Yoon, Hyung Joo;Ko, Hyeon-Jin
    • Journal of Apiculture
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    • v.33 no.4
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    • pp.239-250
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    • 2018
  • We investigated the pollination activity of honeybees (Apis mellifera L.) in terms of different climatic conditions in the greenhouse cultivation of watermelons (Citrullus lanatus L.) during winter. The aim of the study was to search a climatic condition which effectively can be use honeybees as pollinators during the flowering season of watermelons in winter or early spring. The average climatic conditions inside the greenhouse during the bee activity time (BAT)-between 10:00 and 16:00 in mid-Februarywere a temperature of $30.4^{\circ}C$, relative humidity of 53.7%, illuminance level of 22,728.4lx, and UV level of $0.233mW/cm^2$. Bee traffic and foraging activity were at their greatest at 10:00 and tended to decrease with time. Male watermelon flowers typically dehisced between 10:00 and 12:00. Climatic conditions were significantly correlated with bee activities, including bee traffic and foraging activity. Bee activities were positively correlated with temperature, illuminance level, and UV level but negatively correlated with relative humidity. Temperature had the greatest effect on honeybee behavior. Among the foraging honeybees, the number of high-flying bees that did not pollinate flowers showed a strong positive correlation with temperature, and the number of bees landing on the flowers showed a positive correlation with the UV level. The temperature range inside greenhouses at which the pollination activities of honeybees can be maintained efficiently during winter watermelon pollination was found to be $21{\sim}25^{\circ}C$.

Diurnal Roosts Selection and Home Range Size in the Myotis Aurascens (Chiroptera: Vespertilionidae) Inhabiting a Rural Area (교외지역에 서식하는 Myotis aurascens의 주간휴식지 선택 및 행동권 크기)

  • Chung, Chul Un;Kim, Sung Chul;Han, Sang Hun
    • Journal of Environmental Science International
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    • v.22 no.9
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    • pp.1227-1234
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    • 2013
  • Between July and October 2011, radio-tracking was used to analyze the characteristics of home ranges and day roosts of Myotis aurascens by using 3 individuals (male: 2, female: 1). Bat capturing was conducted at a bridge and a nearby forest in Ulju-gun, Ulsan-si. We attached radio transmitters (0.32 g) to the bats and monitored them by using a radio receiver with a Yagi antenna. Home-range analysis of M. aurascens by using 100% minimum convex polygon (MCP) and 95% MCP showed an average of 106.5 ha and 89.3 ha, respectively, and 50% kernel home range (KHR) showed an average of 8.4 ha. Home range overlap of the 3 bats was observed at the bridge and at nearby water bodies as the core areas, and the size of the home range overlap was 7.3 ha by 100% MCP, 5.9 ha by 95% MCP, and 1.6 ha by 50% KHR. The home range for each bat consisted of the main foraging sites, and the types of foraging sites were similar. M. aurascens-01(M-01) used the bridge and nearby water bodies as the nightly main core areas, M. aurascens-02(M-02) used rice fields and water bodies adjacent to the forest as core areas, and M. aurascens-03(M-03) used water bodies and resident areas as core areas. Although rice fields and resident sites represented the core areas of the home ranges of M-02 and M-03, habitat use was the highest near water bodies as the core area for all the 3 bats. The types of day roosts in this study were a wooden house, canopies of a broad-leaved woodland, and banks of rice fields. The roosts in the wooden house and canopies of the broad-leaved woodland were located within the forest, and the roost in the banks of rice fields was also adjacent to the forest. Our results revealed that the main home range and foraging sites of M. aurascens were located near water bodies as the core area, and forests and places adjacent to the forests were used as day roosts.

The Food Habits and Habitat Use of Yellow-Throated Martens(Martes flavigula) by Snow Tracking in Korean Temperate Forest During the Winter (눈 위 발자국 추적을 통한 담비의 겨울철 생태특성 파악)

  • Woo, Donggul;Choi, Taeyoung;Kwon, Hyuksoo;Lee, Sanggyu;Lee, Jongchun
    • Journal of Environmental Impact Assessment
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    • v.24 no.5
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    • pp.532-548
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    • 2015
  • The winter ecology of individual yellow-throated martens(Martes flavigula) intemperate region of Korea were studied through snow-tracking. The study was performed across 3 winter seasons, from January 2011 to February 2013. Total distance of 49.8km was snow tracked (comprising 13 snow-tracking routes) to determine winter foraging habits, general behavior and movement paths of solitary and small groups (1-6 individuals; $mean=2.9{\pm}1.6$) of yellow-throated martens. The martens in the current study were omnivorous, with their winter diet including 9 animal and 5 plant species. Yellow-throated martens searched for food near and under the fallen logs and branches, root plates of fallen trees, around the roots of growing trees, and in small holes in the ground. They also climbed trees to search inside the tree holes and vacant bird nests. Foraging activity was estimated to occur at a frequency of 1.20 times/km, while territory marking occurred 1.42 times/km on average. Of the 60 documented foraging activities we observed, 17 were successful (28.3%). Moving activity and territory marking mainly occurred along ridges, whereas foraging activity was recorded in valleys, slopes, and forest edges. To protect the habitat of this species, the entire forest should be preserved, including the valleys, slopes, and even forest edges as well as main ridges.

Diets and Foraging Tactics of Eurasian Eagle Owls(Bubo bubo) in Two Different Habitat Types (서로 다른 환경에서 서식하는 수리부엉이(Bubo bubo)의 먹이 이용)

  • Nam, Hyun-Young;Lee, Woo-Shin;Choi, Chang-Yong
    • Korean Journal of Environment and Ecology
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    • v.21 no.1
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    • pp.30-37
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    • 2007
  • Pellets and prey remains were analyzed to compare diets and foraging tactics of Eurasian eagle owls (Bubo bubo) in two different habitat types: forested areas and open fields. Overall 150 prey items of three taxa were identified from 66 pellets and 82 prey remains, and the birds were the most important prey in biomass (78.04%) and in frequency (56.67%). Eurasian eagle owls frequently used rats (Rattus spp.), ring-necked pheasants (Phasianus colchicus), and stripped field mice (Apodemus agrarius), but the ring-necked pheasant was most important in biomass in both habitat types. The owls generally foraged various prey in biomass but the mean mass of vertebrate prey used by the Eurasian eagle owls was 503.3g in central Korea. According to the comparison of diets in the two different habitat types, the owls used bigger and more diverse prey in forested areas than in open fields. In forested areas, the Eurasian eagle owls frequently foraged the pheasants and Mandarin ducks (Aix galericulata), but they preferred prey of particular sizes to prey of particular taxa. In open fields, however, the owls showed opportunistic foraging tactics by selecting many small mammals such as rodents or a few large birds.

Request Distribution for Fairness with a Non-Periodic Load-Update Mechanism for Cyber Foraging Dynamic Applications in Web Server Cluster (웹 서버 클러스터에서 Cyber Foraging 응용을 위한 비주기적 부하 갱신을 통한 부하 분산 기법)

  • Lu, Xiaoyi;Fu, Zhen;Choi, Won-Il;Kang, Jung-Hun;Ok, Min-Hwan;Park, Myong-Soon
    • The KIPS Transactions:PartA
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    • v.14A no.1 s.105
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    • pp.63-72
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    • 2007
  • This paper introduces a load-balancing algorithm focusing on distributing web requests evenly into the web cluster servers. The load-balancing algorithms based on conventional periodic load-information update mechanism are not suitable for dynamic page applications, which are common in Cyber Foraging services, due to the problems caused by periodic synchronized load-information updating and the difficulties of work load estimation caused by embedded executing scripts of dynamic pages. Update-on-Finish algorithm solves this problem by using non-periodic load-update mechanism, and the web switch knows the servers' real load information only after their reporting and then distributes new loads according to the new load-information table, however it results in much communication overhead. Our proposed mechanism improve update-on-finish algorithm by using K-Percents-Finish mechanism and thus largely reduce the communication overhead. Furthermore, we consider the different capabilities of servers with a threshold Ti value and propose a load-balancing algorithm for servers with various capabilities. Simulation results show that the proposed K-Percents-Finish Reporting mechanism can at least reduce 50% communication overhead than update-on-finish approach while sustaining better load balancing performance than periodic mechanisms in related work.