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        검색결과 3

        1.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
         ,  , Temperature-related parameters of Panonychus citri (McGregor) (Acarina: Tetranychidae) development were estimated and a stage-structured matrix model was developed. The lower threshold temperatures were estimated as 8.4℃ for eggs, 9.9℃ for larvae, 9.2℃ for protonymphs, and 10.9℃ for deutonymphs. Thermal constants were 113.6, 29.1, 29.8, and 33.4 degree days for eggs, larvae, protonymphs, and deutonymphs, respectively. Non-linear development models were established for each stage of P. citri. In addition, temperature-dependent total fecundity, age-specific oviposition rate, and age-specific survival rate models were developed for the construction of an oviposition model. P. citri age was categorized into five stages to construct a matrix model: eggs, larvae, protonymphs, deutonymphs and adults. For the elements in the projection matrix, transition probabilities from an age class to the next age class or the probabilities of remaining in an age class were obtained from development rate function of each stage (age classes). Also, the fecundity coefficients of adult population were expressed as the products of adult longevity completion rate (liiongevity) by temperature-dependent total fecundity. To evaluate the predictability of the matrix model, model outputs were compared with actual field data in a cool early season and hot mid to late season in 2004. The model outputs closely matched the actual field patterns within 30 d after the model was run in both the early and mid to late seasons. Therefore, the developed matrix model can be used to estimate the population density of P. citri for a period of 30 d in citrus orchards.
        4,200원
        2.
        2008.05 구독 인증기관·개인회원 무료
        Deraeocoris brevis Knight (Hemiptera: Miridae) is a generalist predator and is a key natural enemy in pear orchards in the northwestern United States. Although D. brevis undoubtedly contributes to the regulation of major pear pests, pesticides often disrupt its activity and reduce its effectiveness as a biological control agent. A temperature-dependent stage-structured matrix model was developed to analyse the population dynamics of D. brevis influenced by insecticides. In this study, impacts of acetamiprid on field populations of D. brevis were analysed. The age class of D. brevis was categorized into four stages: eggs, small nymphs (1st to 3rd instar), large nymphs (4th to 5th instar), and adults. Probabilities for each element in the projection matrix were estimated using published temperature-dependent developmental data of D. brevis. Transition probabilities from an age class to the next age class or the probabilities of remaining in the age class were obtained from development rate function of each stage (age classes). The fecundity coefficients of adult population were the products of adult longevity completion rate (1/longevity) and temperature-dependent total fecundity. Also, direct and indirect residual effects of acetamiprid were incorporated into the model. The model results were much overestimated compared with observed actual data from 25d after model running. Such a discrepancy might be occurred from various reasons such as an intra-species competition, successful fecundity rate, etc. Further, the improvement and application of the model were discussed.
        3.
        2015.02 서비스 종료(열람 제한)
        기후변화 모델을 통해 미래 전망에 대한 연구를 수행하는 것은 다양한 분야에서의 적응과 대응 전략을 수립하고 이상기후에 대한 영향을 최소화하고자 하는데 그 목적이 있다. 본 연구에서는 총 20개의 기후변화 모델 자료(1981∼2100년)를 수집하였으며 미래 시나리오는 RCP 4.5와 8.5시나리오를 사용하였다. 한강유역을 대상으로 지역오차보정을 통해 지역적인 스케일의 불일치를 개선하고 특히, 미래 시나리오에 대해서는 비정상성 분위사상법을 통해 미래 시나리오의 추세가 왜곡되지 않도록 하는 NSQM기법을 제안하였다. 베이지안 모델 평균기법(BMA)을 적용하여 각 관측소별로 가중치가 높은 모델만을 선별한 최적의 모델 조합을 통해 강우자료의 정확성과 신뢰도를 확보하였다. 베이지안 앙상블 강우의 R2=0.54, NSE=0.53, RMSE=90.49 mm로 단일모델에 비해 상대적으로 개선된 결과를 나타내었다. 미래 시나리오에 대한 전망결과 온실가스 배출농도가 높은 RCP 8.5 시나리오의 증가율이 RCP 4.5 시나리오에 비해 더 크게 나타났다. 또한 극치수문사상분석을 위해 GEV Scaling과 SPI가뭄지수를 이용한 홍수 및 가뭄의 IDF와 SDF곡선을 전망하였다. 확률강우량 산정 결과 관측기간의 500년 빈도, 지속시간 10분에 해당되는 강우강도가 224.1 mm/hr인 것에 비하여 RCP 4.5, RCP 8.5 시나리오 각각 279.8 mm/hr, 299.7 mm/hr로 기준 시나리오에 비해 증가하는 전망 결과를 나타냈다. 가뭄의 경우, 한강유역은 가뭄에 대한 민감도가 낮은 것으로 전망되었다. 본 연구를 통해 불확실성을 줄이고 다양한 통계적인 분석결과를 제시함으로써 극치수문사상의 전망이 가능하였다. 이를 통해 수자원 변동성과 취약성을 파악하고 수자원 계획 및 운영을 위한 정보 제공에 도움을 줄 것으로 판단된다.