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数值地形图的生成及其水文地貌特征评价 总被引:17,自引:2,他引:15
数值地形图(DEM)是利用地理信息系统(GIS)进行流域水文模拟的基础, 其精度直接影响模拟结果在没有现成的数值地形图时, 应用人员往往利用传统的地形图来生成它. 本文分别采用Arc/Info地理信息系统软件提供的哈奇逊法和不规则三角网五次插值法, 对一个实验流域的高程取样点进行插值, 生成了4种不同的数值地形图, 从凹洼分布、流域界定、河网提取、地面坡度和地形指数、以及地面径流汇成等方面, 对它们的水文地貌精度进行了比较. 结果表明, 两种方法都能生成由高程点群所反映的地形, 然而由于哈奇逊法能够结合流域的河网结构及其具有物理基础的水文地貌加强法来处理凹洼问题, 因此大大地提高了其所生成的流域数值地形图水文地貌特征精度. 相似文献
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This article presents an in-depth qualitative study using a phenomenological approach to understand loneliness among elderly individuals in Malaysia. The objective of the study was to understand how the Malaysian elderly perceive and understand social isolation as well as loneliness, with the aim of identifying the factors that cause emotional loneliness among the elderly in nursing homes. In addition, this study also explored their coping strategies when dealing with loneliness. Semi-structured interviews were conducted with ten elderly participants from two different nursing homes in Kuala Lumpur and Selangor with representatives from the three major ethnic groups of Malaysia. Based on the results, there are several factors that cause the elderly to feel lonely – health factors, lack of family ties, and the lack of communication and cognitive factors, such as memory and perception. It was also found that internal (expectations and optimism) and external (work and activities) coping strategies play major roles in overcoming loneliness. In conclusion, some recommendations are made to respective party families and the government to consider when developing plans to help the elderly overcome loneliness, which could strengthen the family and social support system in Malaysia. 相似文献
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R Jayawardena S Swaminathan NM Byrne MJ Soares P Katulanda AP Hills 《Nutrition journal》2012,11(1):63
ABSTRACT: BACKGROUND: Food Frequency Questionnaires (FFQs) are commonly used in epidemiologic studies to assess long-term nutritional exposure. Because of wide variations in dietary habits in different countries, a FFQ must be developed to suit the specific population. Sri Lanka is undergoing nutritional transition and diet-related chronic diseases are emerging as an important health problem. Currently, no FFQ has been developed for Sri Lankan adults. In this study, we developed a FFQ to assess the regular dietary intake of Sri Lankan adults. METHODS: A nationally representative sample of 600 adults was selected by a multi-stage random cluster sampling technique and dietary intake was assessed by random 24-h dietary recall. Nutrient analysis of the FFQ required the selection of foods, development of recipes and application of these to cooked foods to develop a nutrient database. We constructed a comprehensive food list with the units of measurement. A stepwise regression method was used to identify foods contributing to a cumulative 90% of variance to total energy and macronutrients. In addition, a series of photographs were included. RESULTS: We obtained dietary data from 482 participants and 312 different food items were recorded. Nutritionists grouped similar food items which resulted in a total of 178 items. After performing step-wise multiple regression, 93 foods explained 90% of the variance for total energy intake, carbohydrates, protein, total fat and dietary fibre. Finally, 90 food items and 12 photographs were selected. CONCLUSION: We developed a FFQ and the related nutrient composition database for Sri Lankan adults. Culturally specific dietary tools are central to capturing the role of diet in risk for chronic disease in Sri Lanka. The next step will involve the verification of FFQ reproducibility and validity. 相似文献
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利用双抛物线型土壤蓄水容量曲线对新安江产流模型的改进 总被引:3,自引:0,他引:3
提出了双抛物线型土壤蓄水容量关系曲线,对新安江模型产流计算公式进行了改进。利用珠江三角洲不同土壤水分状态的多年水文资料,对改进前和改进后新安江模型产流计算公式进行了比较。结果表明,双抛物线型关系曲线能够代表流域中多种土壤水分状态并存的情况,包括湿润、干燥以及从湿润到干燥过渡阶段,而原单抛线型的模型则是双抛物线的一个特例,只能反映单一土壤水分状态的分布。对于那些发生在湿润季节的暴雨,两种曲线的模拟精度相当,但对于发生在旱季及旱湿过渡时期的暴雨,双抛物线明显优于单抛物线。 相似文献
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A. W. Jayawardena & D. Achela K. Fernando 《Computer-Aided Civil and Infrastructure Engineering》1998,13(2):91-99
In this paper, the applicability of the radial basis function (RBF) type artificial neural networks (ANNs) approach for modeling a hydrologic system is investigated. The method differs from the more widely used multilayer perceptron (MLP) approach in that the nonlinearity of the model is embedded only in the hidden layer of the network. Search for optimal model parameters is carried out in two steps, each of which can be made to be more efficient and much faster than in MLP. This approach is applied to simulate runoff discharges in a small catchment. The results show that the models based on RBF networks can predict runoff with accuracy comparable with that with the MLP approach. An added advantage of RBF network-based models is that they can be developed with relative ease and with much less time compared with their MLP counterparts. 相似文献
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Lakshmie Ranasinghe Bimali Jayawardena & Krishanthi Abeywickrama 《International Journal of Food Science & Technology》2005,40(1):97-103
Mature Embul (Musa, AAB) bananas were treated with emulsions of either cinnamon bark or leaf (Cinnamomum zeylanicum) or clove (Syzygium aromaticum) oils to control post‐harvest diseases, packed under modified atmosphere (MA) using low‐density polyethylene (0.075 mm, LDPE) bags, and stored in a cold room (14 ± 1 °C, 90% RH) or at ambient temperature (28 ± 2 °C). The effects of the essential oils on post‐harvest diseases; physico‐chemical properties and organoleptic properties were determined and compared with controls and bananas treated with benomyl. Treatments with cinnamon bark and leaf oils controlled crown rot, whereas clove oil treatment did not affect crown rot development. Treatment with emulsions of cinnamon oils combined with MA packaging can be recommended as a safe, cost‐effective method for extending the storage life of Embul bananas up to 21 days in a cold room and 14 days at 28 ± 2 °C without affecting the organoleptic and physico‐chemical properties. 相似文献
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S. Reshan Jayawardena James D. Morton Charles S. Brennan Alaa El-Din A. Bekhit 《International Journal of Food Science & Technology》2019,54(3):610-618
Beef lungs are an underutilised co-product of the meat industry that could be used as an ingredient to supplement the protein content of cereal foods. Beef lung powder (BLP) had a protein content of 87% (dry weight basis), an amino acid score of 1, and contained 1 mg g−1 iron. Fresh semolina pasta was used as a model food, and BLP was incorporated up to 20%. Incorporation of 10% BLP improved the indispensable amino acid score of the pasta from 0.48 to 0.91. At that level of incorporation, higher cooking loss and redder (increased ‘a’ value) and darker (decreased ‘L’ value) colour resulted. The fresh pasta with BLP had a lower glycaemic response compared to control samples. BLP improved the functional value of the fresh pasta and is a potential ingredient in the development of new food products. 相似文献
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Chandimal Jayawardena Keigo Watanabe Kiyotaka Izumi 《Neural computing & applications》2007,16(2):155-166
Natural language commands are generated by intelligent human beings. As a result, they contain a lot of information. Therefore,
if it is possible to learn from such commands and reuse that knowledge, it will be a very efficient process. In this paper,
learning from such information rich voice commands for controlling a robot is studied. First, new concepts of fuzzy coach-player
system and sub-coach are proposed for controlling robots with natural language commands. Then, the characteristics of the
subjective human decision making process are discussed and a Probabilistic Neural Network (PNN) based learning method is proposed
to learn from such commands and to reuse the acquired knowledge. Finally, the proposed concept is demonstrated and confirmed
with experiments conducted using a PA-10 redundant manipulator. 相似文献
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Takano Y Sakai H Watanabe E Ideguchi-Ohma N Jayawardena CK Arai K Asawa Y Nakano Y Shuda Y Sakamoto Y Terashima T 《Journal of electron microscopy》2003,52(6):573-580
The mechanism whereby a region-specific deposition of the two types of cementum (cellular cementum and acellular extrinsic fibre cementum) is regulated on the growing root surface was tested using bisphosphonate-affected teeth of young rats and guinea pigs. The animals were injected subcutaneously with 8 or 10 mg P x kg body weight(-1) x day(-1) of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 1 or 2 weeks. In rat molars, HEBP prevented mineralization of newly formed root dentin matrix and totally inhibited de novo deposition of acellular extrinsic fibre cementum. Instead, thick cellular cementum was induced on the non-mineralized root dentin surface, irrespective of the position of the root. In both animals, cellular cementum was also induced on the non-mineralized surface of root analogue dentin in HEBP-affected incisors, where only acellular extrinsic fibre cementum is deposited under normal conditions. In normal rat molars, dentin sialoprotein (DSP) was concentrated along the dentin-cellular cementum border, but not that of dentin and acellular extrinsic fibre cementum. In HEBP-affected rat incisors, DSP was shown to penetrate through the non-mineralized dentin into the surrounding tissues, but not through the mineralized portions. These data suggest that, at the site of cellular cementum formation, putative inducing factors for cellular cementum might diffuse into the periodontal space through the newly deposited mantle dentin matrix before it is mineralized. At earlier stages of root formation, mantle dentin might mineralize more promptly not to allow such diffusion. The timing of mineralization of mantle dentin matrix might be the key determinant of the types of the cementum deposited on the growing root surface. 相似文献