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        검색결과 97

        23.
        2016.04 구독 인증기관·개인회원 무료
        Information on spatial distribution and peak occurrence is important for site and time specific pest management. So, we investigated seasonal occurrence and edge distribution of major soybean pests by visual count in six commercial fields located in Andong from July 16 to October 23 in 2015. We found a total of 19 species in 10 families. The major pest during vegetative stage was Medythia nigrobilineata (Motschulsky) while Riptortus pedestris (Fabricius) and Halyomorpha halys (Stal) showed peak occurrence during reproductive stage of soybean. Aphis glycines Matsumura was found throughout the season. Seasonal density of M. nigrobilineata was 0.20 and 0.38/plant in edge and interior without significance, respectively. The infestation of A. glycine was also found similar between edge and interior. Immatures of R. pedestris and H. halys distributed more in edge (0.21 and 0.36/plant) than interior (0.12 and 0.12/plant), respectively. The application of these informations on spatial distribution pattern of soybean pest was discussed.
        24.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 굽힘하중이 가해지는 스마트 복합재 적층판의 자유단에서 발생하는 박리응력을 압전 작동기를 이용해서 감소시키는 방법을 응력함수를 이용해 해석하는 방법을 제안하였다. 전기-기계 연성에 의해 나타나는 지배방정식은 최소 보족일의 원리를 이용해 구하였다. 응력상태는 일반적인 고유치 해석과정을 통해 구하였다. 스마트 복합재 적층판의 자유단 박리응력은 압전 작동기를 이용해 감소시킬 수 있었다. cross-ply 복합재 적층판의 박리응력 감소가 angle-ply 복합재 적층판 보다 크게 나타났다.
        4,000원
        25.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.
        4,000원
        26.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2차원 수중날개의 뒷날에 회전자를 부착한 고양력 발생장치의 성능을 파악하고, 실용화가능성을 살펴보기 위하여 NACA0020형상을 이용하여 모형을 제작하였고 캐비테이션 터널에서 실험을 수행하였다. 양력, 항력, 모멘트의 세 방향의 힘을 계측할 수 있는 가는 막대 형상의 로드셀을 부착하여 유체력을 계측하였으며, 뒷날에 부착된 회전자는 터널 외부에 설치된 DC 서보모터로 회전속도를 제어하였다. 다양한 편향각 조건과 회전자의 회전속도에 따른 체계적인 실험을 통하여 회전자의 효과를 확인하였다. 회전자의 회전속도에 의해 순환제어가 수월하게 조절 가능하다는 점을 실험을 통하여 검증하였으며 회전자의 회전속도에 따라 2배 이상의 양력이 발생함을 확인하였다. 따라서 제안한 양력 장치는 양력조절이 가능한 고양력 발생장치로 충분히 활용할 수 있음을 확인하였다.
        4,000원
        27.
        2015.04 구독 인증기관 무료, 개인회원 유료
        This study numerically investigates buckling behavior of press braked steel plates with a free edge. In order to improve structural stability during construction, the top flanges of press-braked U section girder are laterally braced by the installation of prefabricated half-deck. Thus, an unbraced length is taken as the longitudinal spacing of pockets on the half-deck, which are to make composite section. This study performed 3D finite element analyses to evaluate an equivalent effective width of cold-formed flange with a free edge. Through the parametric numerical analyses, the elastic buckling stresses of the cold-formed flanges with rounded corner in the cross-section were compared with those of general flat plates. Then, the equivalent effective width of the cold-formed (press-braked) flanges were numerically examined for some representative cases.
        3,000원
        28.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Bar type waveguides are frequently employed as a buffer rod between ultrasonic senor and hard-to-access object in many measurement applications. Difficulty in pulse echo measurements using a buffer rod is caused by spurious echoes due to reflection, mode conversion and interference within the buffer rod of finite size. These spurious echoes degrade the signal to noise ratio (SNR) because of their possible interference with desired target signals. A tapered buffer rod or rods with non-symmetrical cross sections were used before to reduce these unwanted spurious echoes. In this paper, we propose signal processing techniques to remove the spurious echo signals. Experiments were performed in order to examine the refocusing and recovering the initial input waveform in the long range propagation of ultrasonic waves in cylindrical waveguides. Two different time reversal processes (regular TR and reciprocal TR or inverse filtering) are tested and the experimental results were compared
        4,000원
        29.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The camera embedded wall climbing robot in this paper combines the suction and aerodynamic attraction to achieve good balance between strong adhesion force and high mobility and adopts embedded image processing technique to detect targets on the warehouse inspection. Experimental results showed that the robot can move upward on the wall at the speed of 2.9m/min and carry 5kg payload in addition to 2.5kg self-weight, which record the highest payload capacity among climbing robots of similar size. With two 11.1V lithium-polymer battery, the robot can operate continuously for half hours. A wireless camera system, zigbee protocol module and several sensors was adopted for detecting target objects and dangerous situation on the wall and for sending alarm signals to remote sensor node or manager.
        4,000원
        30.
        2013.10 구독 인증기관·개인회원 무료
        In recent, habitat fragmentation is one of the major factors to threat to biodiversity loss, because habitat fragmentation caused by urbanization and land-use change affect reducing of habitat amount and changing of environmental condition. In particular, increasing of forest edges by habitat fragmentation cause changing of microclimate and distribution of organisms in forest. This study was conducted to examine the distributional patterns of ground beetle assemblages along forestedge- crop gradients in Hoengseong-gun, Gangwon-do. We selected 8 study sites as line gradients from forest interior to crop (+80m, +40m, +20m, 0m, -20m, -40m, -80m). Ground beetles were collected by pitfall traps from May to October in 2012. A total of 61 species were identified from 3,739 collected beetles. Species richness was the highest at forest edge (GLM with Tukey’s test, F6, 49=2.56, P=0.031). Although abundance was higher at both forest interior and edge, but not showed statistical significance (F6, 49=2.06, P=0.076). Species composition of forest interiors were significantly different from forest exteriors (crops) by non-metric multidimensional scaling (NMDS) and cluster analysis with similarity profile test (SIMPROF), while forest edges showed intermediate characteristics. Although our study sites may not represent the overall Korean forest, we confirmed that forest edges are important habitats for generalists and open-habitat species as well as forest specialists. In conclusion, management of both forest edge and its surroundings are needed to conserve biodiversity in forest,
        31.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        From the end of 2000, the era of full-fledged remote college education has opened and online education is evolving rapidly. However, the liberal literary education takes place in cyberspace university level, in most cases, is staying general education. In this paper, we designed EDGE (E-learning Design for Go through effectively a novel on literature class, EDGE) learning model to teach novel using the characteristics of literary education and online education. EDGE learning model proposed in this paper, students can hosts lecture spaces to get in-depth understanding of the literature, can have a variety of literary experience and can interact each other actively. Future research includes developing unique online teaching type which enables literature concept delivering and teaching creative writing simultaneously.
        4,000원
        32.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, composite laminate cantilever type cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Two models by load conditions are considered. Load type A and B are loaded by point load at the free edge and line load respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced minimum 30% by appropriate edge-stiffeners.
        4,000원
        33.
        2012.05 구독 인증기관·개인회원 무료
        We investigated the spatial distribution of ground beetle species from the edge of secondary forests in Hwaseong-si, Gyeonggi-do. Nine secondary forests were selected, and 81 pitfall traps for collecting ground beetles were placed along forest interior―forest edge―forest exterior gradients during 14 June to 9 November, 2011. A total of 32 species belonging to 13 genera of 8 subfamilies were identified from 3710 collected ground beetles. Ten dominant species were selected for analysis. Five species such as Chlaenius micans (ANOVA, with Tukey's test, F2, 78=3.11, P=0.0502), Chlaenius ocreatus (F2, 78=2.76, P=0.0692), Dolichus halensis halensis (F2, 78=9.80, P=0.0002), Harpalus eous (F2, 78=2.73, P=0.0712), and Harpalus tridens (F2, 78=6.74, P=0.0020) were abundant at forest exterior. Three species such as Synuchus cycloderus (F2, 78=7.91, P=0.0007), Synuchus nitidus (F2, 78=9.72, P=0.0002), and Synuchus sp.1 (F2, 78=4.50, P=0.0142) were abundant at forest edge and forest interior. Coptolabrus smaragdinus branickii (F2, 78=3.24, P=0.0444) was abundant at forest edge and exterior. Finally, Chlaenius naeviger (F2, 78=1.39, P=0.2542) showed a wide distribution in this study. This study showed a significant edge effect on dominant ground beetles. Many environmental variables and prey items may be important factors for the spatial pattern of ground beetles. Because forest edges are generally important for many predaceous arthropods including ground beetles, the conservation and management of forest edges are important for maintaining biodiversity and ecosystem functions.
        34.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        교량단면 등에 이용되는 날카로운 모서리를 갖는 형상 주위의 유동은 기존의 전산 유체 해석에 있어서 격자 생성이나 수치적 안정성 측면에서 매우 어려운 문제를 제기한다. 최근 많이 적용되고 있는 직교격자 기반의 가상경계법도 물체면에서 점착조건을 위해 운동량 보정을 물체 내부에 적용하는 외삽법을 이용하는데, 삼각형 단면과 같은 날카로운 모서리를 갖는 형상 주위 유동 해석에 있어 수치적 불안정성을 나타낸다. 이에 본 논문에서는 보정량이 유체 내에 작용하는 내삽법을 날카로운 모서리 형상 주위의 유동해석에 적용하였다. 개발된 방법을 이용하여 정삼각형 단면 주위의 비정상, 비압축성의 2차원 층류 유동을 해석하였으며, Re=100~250의 유동에 대해 기존의 연구 결과와 비교를 통해 검증하였다. Re가 250의 유동장에 대해 다양한 변장비의 이등변삼각형 형상 주위의 해석 결과 변장비 증가에 따른 항력감소와 양력 변동량의 증가를 나타내었으며, 특히 풍상측이 수직인 경우 변장비 증가는 박리 유동의 재부착과 장주기의 와흘림으로 인한 저주파 대진폭의 양력 변동이 나타남을 알 수 있다.
        4,000원
        37.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mating disruption (MD) using synthetic sex pheromone lures has been used to control the Oriental fruit moth, Grapholita molesta (Busck), in apple orchards. In Korea, where several small apple orchards are clustered but independently managed, its efficacy has been suspected mainly due to immigration of any mated females from nearby untreated cultivating areas. This study developed an edge treatment technique to decrease any local MD-free zones in a specific MD-treated farm and to trap any immigrating mated females by installing MD lures and food traps around the apple farm with 10 meter intervals. The addition of the edge treatment to the MD significantly prevented leaf and fruit damages induced by G. molesta compared to MD only. Moreover, this study tried to optimize the MD control technique by determining frequency of MD application. It suggests two MD applications with the edge treatment at the end of March and at the early of July to be effective throughout the entire apple growing seasons.
        4,000원
        38.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Recently, metal molding has become essential not only for automobile parts, but also mass production, and has greatly influenced production costs as well as the quality of products. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and, when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate this, microstructural changes and hardness characteristics of three parts (the surface treatment part, heat affect zone, and parental material) are observed with the change of laser beam speed and surface temperature. Moreover, the depth of the hardened area is observed with the change of the laser beam speed and temperature.
        4,000원
        39.
        2008.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 숲길에 대한 생태학적 접근을 통하여 숲길과 숲 가장자리의 상부와 지하부식생을 비교하고 그 특성을 밝히는 것을 목적으로 하고 있다. 연구 장소는 잣나무와 전나무를 식재한 숲으로, 해발 고도는 45m이다(36˚36'23''N127˚21'45''E). 숲길의 폭은 3.2m이며, 숲 가장자리는 숲 길가로부터 5m로 정하였다. 2006년 9월부터 2007년 8월까지 총 5번의 식생조사가 이루어졌다. 매토종자 분석을 위해 숲길과 숲 가장자리에서 각각 18곳의 방형구를 정하였다. 각각의 방형구마다 토양 샘플러로 600cm3 토양을 채취하였고 저온처리를 위하여 한 달간 냉장 보관하였다. 포트에 토양을 골고루 얇게 펼친 후 4~5일마다 급수하였으며, 더 이상 발아가 일어나지 않는 상태가 될 때까지 실험을 6개월 동안 실시하였다. 출현한 유식물의 이용하여 종과 발아개체수를 확인하였다. 연구 결과, 전체적으로 지상부식생과 지하부식생 사이의 유사도지수는 낮았다. 숲길과 숲 가장자리의 지상부식생간의 상관계수는 0.36으로 상관관계가 있었다(p〈0.05). 매토종자 분석을 통한 지하부식생간의 상관계수는 0.20로, 서로 상관관계가 없었다(p〉0.05). 귀화식물 조사결과, 목본을 포함하였을 경우 숲길 귀화식물은 7종, 귀화율은 12.50%이었으며, 도시화지율은 2.61%이었다. 숲가장자리 귀화식물은 6종, 귀화율은 11.11%이었으며, 도시화율은 2.24%이었다. 귀화식물 중 목본을 포함하지 않았을 경우 숲길의 귀화율은 12.50%이나 숲 가장자리의 귀화율은 9.09%이었다.
        4,200원
        40.
        2008.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 아스팔트 혼합물의 변형강도시험에서 하중봉의 치수가 변형강도 특성에 미치는 영향을 평가하였다. 이를 위하여 직경(D) 40mm, 하단의 원형 절삭 반경(r)을 10.0mm와 10.5mm로 제작한 두 개의 하중봉으로 아스팔트 혼합물의 변형강도를 측정하고, 반복주행시험을 수행하여 얻어진 소성변형 특성치와 상관성 분석을 하였다. 또한 하중봉의 원형 절삭반경에 따른 골재치수에 어떠한 영향을 미치는지를 확인하기 위하여 통계 분석을 하였다. 변형강도 값과 변동계수는 r=10mm하중봉을 사용한 것이 더 낮은 것으로 나타났다. 또한 r=10mm 하중봉이 변형강도와 소성변형 특성치와 상관성 분석에서도 더 높은 상관성을 보였다. 골재치수와 원형 절삭반경은 변형강도에 영향을 미치는 것으로 나타났으나 두 변수의 교호작용에서는 골재의 크기가 10mm~19mm내에서는 r에 영향을 받지 않는 것으로 나타났다. 따라서 소성변형과의 상관성이 더 우수하며 변동계수도 낮은 것으로 나타난 D=40mm, r=10.0mm의 하중봉을 사용하는 것이 적합할 것으로 판단되었다.
        4,000원
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