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71.
Morten?O.?AlverEmail author Jo?A.?Alfredsen Gunvor??ie 《Aquaculture International》2005,13(6):519-541
High and unpredictable mortality rates are observed in the larval rearing of cod (Gadus morhua). As a means of addressing this problem, we present a model-based estimator system which can be used to indirectly measure
the larval density through monitoring the live food dynamics and larval growth. The estimator has been evaluated in a conceptual
context using a preliminary model formulation, and the observability of the process has been investigated. It was found that
the two parameters, live food dynamics and larval growth, contain enough information for the larval density to be estimated
under noisy conditions, given the correct model. When the system is applied practically, the estimation error will depend
on the measurement and model accuracy; this is especially true with respect to the predictability of the feed intake rate
of the fish. 相似文献
72.
73.
本文根据清洁水体、浑浊水体和冰体在不同波段的反射率不同,运用C#语言编写黄河凌汛监测系统程序,将水体、冰体检测出来,同时系统运用GIS的地图控件计算水体、冰体面积变化,以实现对黄河凌汛的动态监测. 相似文献
74.
本文主要针对目前各高校监考系统建设现状以及学校多校区发展现状,利用高速校园网及编程技术,将分散在各校区内的监考系统整合为一体,实现各校区考试现场的集中监控. 相似文献
75.
76.
The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientific work on agricultural monitoring and early warning as well as agricultural outlook must be strengthened. In this study, we develop the China Agricultural Monitoring and Early-warning System(CAMES) on the basis of a comparative study of domestic and international agricultural outlook models. The system is a dynamic and multi-market partial equilibrium model that integrates biological mechanisms with economic mechanisms. This system, which includes 11 categories of 953 kinds of agricultural products, could dynamically project agricultural market supply and demand, assess food security, and conduct scenario analysis at different spatial levels, time scale levels, and macro-micro levels. Based on the CAMES, the production, consumption, and trade of the major agricultural products in China over the next decade are projected. The following conclusions are drawn: i) The production of major agricultural products will continue to grow steadily, mainly because of the increase in yield. ii) The growth of agricultural consumption will be slightly higher than that of agricultural production. Meanwhile, a high self-sufficiency rate is expected for cereals such as rice, wheat, and maize, with the rate being stable at around 97%. iii) Agricultural trade will continue to thrive. The growth of soybean and milk imports will slow down, but the growth of traditional agricultural exports such as vegetables and fruits is expected to continue. 相似文献
77.
R. K. Mensah 《国际虫害防治杂志》2013,59(2):95-105
Part 1 of the paper showed that the integration of a lucerne/ cotton interplant system with supplementary food sprays retained and increased populations of predatory insects in the cotton crop. The strategic use of biopesticides (Bacillus thuringiensis (Bt), nuclear polyhedrosis virus (NPV)) reduced the use of synthetic insecticides by 50% without sacrificing cotton yield and profitability. In economic terms, the average gross margin for the IPM plot was A$3255 compared with A$3020 and A$3218 for the plots treated with (1) conventional insecticides on transgenic (Ingard®) cotton and (2) conventional insecticides on non-transgenic cotton. The use of transgenic cotton affected a 25% saving on synthetic insecticide usage. The results clearly indicate that a refined IPM approach could have a distinctive advantages in terms of economic and environmental impacts on cotton production. The success of such an approach lies in a strict adherence to its methodology. 相似文献
78.
高速公路监控系统正日益成为高速公路日常运营管理的一个重要手段,发挥着重要的作用。其主要是通过道路监控摄像机作为视频图像采集系统进行监控的。该文在分析高速公路监控需求的基础上,阐述了对高速公路监控摄像机的性能要求,以及进行监控摄像机的选择时需要考虑的因素。 相似文献
79.
80.
《Arid Land Research and Management》2013,27(4):347-358
Development of rangeland inventory and monitoring was initiated as early as in 1908. The early efforts were simple methods to establish rangeland stocking rates. With advancing scientific methodologies and the recognition for moitoring needs, the evaluation of range conditions and management planning increase well after WWII by a number of US federal agencies. By 1970s the environmental protection measures were first emphasized in the USA and were applied also to rangeland utilization. Since then the approaches and methodologies for evaluation of rangelands have changed periodically by accommodating the tenets of federal administrations. The methodologies applied have been geared either to support the environmental preservation or to support economic exploitation. There is still no system, however, for national or regional reporting on range conditions and trends. Local monitoring and management systems often lack scientific and objective basis. Local surveys, however, are important for evaluating existing conditions and should not be based on national reporting requirements. The ecological site concept has been adopted as the toxonomic unit for rangeland classification. It is important that monitoring methods are not biased, based on sufficient sample sizes, and not based on "estimations". The forage allocation based on one-time inventories are seriously flawed and the methods for evaluating stocking rates must be reevaluated. The same applies to the evaluating the rangeland "health." A unified national reporting system must be developed on scientific and objective basis. 相似文献