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1.
It is important for enterprises' inventory management to find out the optimal production cycle and the length of shortage time,so that the total cost of inventory system can be reduced and the service level can be raised.Based on the classical EPQ model,this paper develops an EPQ model for deterioration items with different lost sale factor relative to the inventory level during shortage period.The existence of unique optimal solution is discussed by mathematic analysis and a numeric example.The sensitivity analysis shows that the parameter of losing sale has different impact on the costs of inventory system.The factors must be considered for the production inventory system to make management decision. 相似文献
2.
The stability of the brake system is a key factor for the vehicle safety.It is important for the air braking system's stability to shorten the time lag between the front brake and the rear brake,the reasonable disposal of the air pipeline and the optimization of the braking system design.A test bench is developed to test the performance of the air braking system,which is mainly made of pressure sensors,signal amplifiers,data acquisition system,computer,pressing air resource and so on.Based on this test bench,the reaction time of the system while braking and abandoning brake can be measured.Using this test bench,the performances of the air braking system of a certain commercial vehicle is detected.Compared with the actual road test,it can save the cost and the time for experiment largely. 相似文献
3.
Application system generally refers to all kinds of computer information system. It aims at improving the sharing and application of the resource. The resource in application system usually means data resource. For computer management and maintenance, there are not only data resource, but also program resource and network resource. Effective management of this resource is key to ensure proper work of the application system. In this paper, the basic pattern and policy for resource management is put forward and a method to build and realize the resource layer that lies between database layer and application layer is to be found. This management layer, which skillfully connects the application system with resource and establishes good base for application and exploitation of system, is named as resource management system. 相似文献
4.
The particle swarm optimization (PSO) algorithm developed in recent years is a stochastic optimization algorithm based on swarm intelligence. It possesses advantages such as being a simple concept, ease of implementation and low resource occupation. The PSO algorithm was adopted to solve the problem of size optimization of truss structures with stress and displacement constraints. We present the basic principle of the original PSO algorithm in detail, and then introduce a constriction coefficient to modify it. Moreover, reasonable values of the coefficients are proposed for the modified PSO algorithm. Several classical problems are solved using the modified PSO algorithm, and the results compared with those using traditional optimization algorithms and genetic algorithms. Numerical results show that the modified PSO algorithm has good convergence and stability, and can be applied to the size optimization of truss structures. 相似文献
5.
Ye Xiaosu Yan Zhe San Xueqin 《保鲜与加工》1998,(4):35
China has a large population of 1.2 billion.To solve the housing problem of middle_low income families and realize a condition,under which people can live in peace and work contentedly,a policy housing financial system(PHFS)with Chinese characteristics must be established.PHFS is a special financial area.The combination of financial relationships,forms and methods related to the purchase,construction or rehabilitation of housing for middle_low income families,is the core of policy housing financial system.It has real meaning for studying theory and practice of PHFS,its role in development of housing industry,and promoting economic growth of the country,civilization and progress of the society. 相似文献
6.
The authors introduce a sort of novel adaptive penalty gene, transform the constrained problem into unconstrained problems. An solution is given for this unconstrained problem with genetic algorithm, and then it is used as initial values for the constrained variable metric method to get precise solution. The numerical experiments illustrate that this hybrid genetic algorithm is more efficient than the genetic algorithm, and at most situations globally optimal solution can be gotten. 相似文献
7.
Huang Kefu 《保鲜与加工》2013,(Z2):60-63
In recent years, economic has developed with the high-speed in China, which leads advance of urbanization rapidly. Development of economic expands the gap between the rich and the poor, leads to house prices rise rapidly. The housing problem is tricky for low-income people. Resolving the housing problem has become one of the hot topics in China. It is so difficult to buy a house with high rent and high price of house, and this is the common difficulties for urban low-income people. The current public housing construction has been launched in most cities, but the public housing system in Shanxi province, construction, management and future problems that exist in the operation process is worth thinking about. For public housing development status quo carries on the analysis of current, the study of public housing security system is of help, through the analysis of the problem can solve the problems existing in the public housing, to consummates our country housing guarantee system. 相似文献
8.
Presently, ECG monitor encounters the trend of miniaturizing, intelligentizing and networking. Short distance and limited channels are shortcomings of the existed telemetric ECG (Electrocardiograph) monitoring system, while the existed remote monitoring system has the disadvantages of high cost and low Data Transfer Rate. Furthermore, neither of these two systems can implement real-time monitoring on the spot. So, an embedded ECG Monitor based on Linux, which successfully solves these problems, is introduced. With embedded system technique, this embedded monitor, which can not only realize real-time monitoring on the spot, but also analyse the ECG data, has the advantages of low cost, small volume, light weight, low power, high stability, powerful networking function and so on. And by communicating through Internet, which has the features of low cost, high data transfer rate and good expandability, it can also send ECG data to monitoring center in order to achieve long-term monitoring. The development of this monitor provides a new solution for medical instruments' implementation and networking, and is of certain reference value. 相似文献
9.
The Data Logger is an important secondary-instrument,which can be applied to automatic monitor and control system,and high speed local data acquisition for later analysis.The Virtual Great Capacity of Data Logger based on virtual instrument technology is a new instrument which has more advantages than the traditional Data Logger.The design method has been introduced from three ways,which includes system principle, hardware configuration and programming design, and an application example is given.This Data Logger is low cost,easy to take,also easy to operate.It can be widely used in many of actual applications. 相似文献
10.
Aiming at site management problems of machining job shop, a site tools management method based on dynamic distribution for machining job shop is proposed. According to the method, the site dynamic distribution plan of machining tools is generated. A site tools distribution management information system is developed. The function and information models of the system are presented. With the system, dynamic distribution and recycling of machining tools and materials is realized. As a result, the inventory of machining tools is reduced, and the productivity is improved. The system has been applied in a machining job shop with satisfied result. 相似文献
11.
我国南方地区旱作农业发展概况与对策分析 总被引：1，自引：1，他引：0
近年来中国南方地区频繁遭遇干旱,给农业生产和人民生活造成了巨大危害。为促进中国南方地区旱作农业的发展,保障南方地区粮食和经济作物安全,总结了中国南方地区旱作农业发展的现状、意义;重点分析了南方地区旱作农业发展中存在的主要问题;提出了南方旱作农业发展的主要对策：加强农田工程建设、选育抗旱品种、加强抗旱保水技术的开发和应用、利用节灌补水技术,提高水资源利用率。 相似文献
12.
影响农户安全农产品生产因素探讨 总被引：6，自引：3，他引：3
农户的生产行为是影响农产品安全的重要源头因素之一,笔者简述了农户安全农产品生产中存在的主要问题,分析了影响农户安全农产品生产的主要因素,进而提出保证农户安全农产品生产的对策建议。 相似文献
13.
史前的山西地方,乃为中华文明的发祥地之一,先人们于近万年前在这里开始了原始的农耕活动。他们使用石质工具——石斧、石耜、石铲、石犁等耕地与整地的简单器械种植作物,并用石锄进行中耕除草和松土保墒作业,继而使用石刀、石镰刈割收获田间的农作物。笔者总结描述了山西地区出土的各种石质工具,指出当时的劳作手段和方法整体而言甚为简略,显得粗糙而原始,还有诸多问题需要解决,但它是新生事物,有许多完善和成熟的机会,前景广阔;进而阐明它的意义在于有意识地干预了田野的生态秩序,彰显了人类对地表地貌的作用力。这一阶段的先民,首先迈出了种禾获粮创食的步伐,以拓荒者的身份勇敢地去开创着原始农业的经济局面。该种农耕方式,为后来农业的精耕细作奠定了深厚而坚实的基础。 相似文献
14.
全球重要农业文化遗产-青田县稻鱼共生系统保护与可持续发展之思考 总被引：3，自引：0，他引：3
浙江青田县龙现村稻鱼共生系统作为全球重要农业文化遗产,其保护和可持续发展的问题现已引起了社会的关注。在调查研究的基础上,分析了青田县龙现村稻鱼共生系统得以长期延续的历史渊源、自然环境条件和人文社会因素等原因。同时,指出了这种稻鱼共生模式在当今市场经济条件下面临的挑战与问题,如市场问题、产业化问题、旅游业发展导致的环境问题、农业文化消失问题等。最后提出了一系列对策措施,如加强全村生态规划,建立稻鱼共生自然保护区,打造稻鱼生产品牌,适度发展农业生态旅游,建立多方参与机制等措施。 相似文献
15.
John E. Bradshaw 《Euphytica》2017,213(3):60
Plant breeders can help farmers increase food production by breeding new cultivars better adapted to their chosen farming systems, but these must be capable of providing the necessary plant inputs for the required levels of crop production in 2050. Until 200 years ago the farmers themselves were the plant selectors. Plant domestications, extensive crop dispersions and farmers’ selections produced thousands of locally adapted landraces of cultivated plants. During the twentieth century these were largely replaced by relatively few high yielding cultivars and the natural habitats of many of their wild relatives became endangered. Hence in situ and ex situ conservation, and evaluation and use of plant genetic resources is vital for future plant breeding. The development of scientific breeding from the beginning of the twentieth century was based on understanding the mechanism of inheritance and the mating systems of crop plants. The types of genetically uniform, high yielding cultivars that have been bred from genetically heterogeneous landraces were determined by the mode of reproduction and mating system of the cultivated plant species: inbred line (wheat) and hybrid (rice) cultivars for inbreeding species, hybrid (maize) cultivars for outbreeding species, and clonal (potato) cultivars for vegetatively propagated species. When genetically heterogeneous crops are desired, mixtures of cultivars and synthetic cultivars can be produced. Future progress in crop improvement will come from three complementary approaches: use of hybridization and selection in further conventional breeding, base broadening and introgression; mutation breeding, cisgenesis and gene editing; and genetically modified crops. 相似文献
16.
小麦和水稻是太仓市主要的粮食作物，为了解太仓市小麦和水稻的气候生产潜力的变化趋势以及光温水条件对其生产潜力的影响程度，本研究收集并整理了太仓市近几十年来的温度、湿度、辐射、降雨等数据信息，分析了太仓市气象条件的变化趋势，并采用联合国粮食和农业组织（FAO）推荐的逐步订正法，估算了太仓市水稻和小麦生育期内的生产潜力和气候资源利用率。结果表明：（1）近几十年来太仓市太阳辐射能量有所下降，而气温和降水量则有所提升；（2）在太仓市气候条件变化影响下，小麦气候生产潜力呈升高趋势，而水稻气候生产潜力没有明显上升或下降趋势；（3）太仓市小麦气候生产潜力受水分条件影响较大，而水稻气候生产潜力则主要受到温度条件的影响；（4）水稻的气候资源利用率范围为38.50%~64.30%，而小麦则更低，仅23.72%~51.39%。综上所述，太仓市水稻和小麦作物的增产潜力仍然很大，可通过监控温度，调整农时，加强水分管理，改善土壤肥力，提高复种指数，引进新品种等途径提高太仓市作物产量。 相似文献
17.
18.
稻鸭共作农作系统的生态效应与技术模式 总被引：7，自引：3，他引：4
稻鸭共作生态技术是将雏鸭全天候放入稻田,利用鸭子不间断的活动来刺激水稻生长、促进物质循环和改善稻田环境,构建了种养结合、节本增效、物质循环的优质安全农产品生产的农作模式,笔者综述了稻鸭共作技术对水稻的物质积累、壮秆效应、根系活力、病虫草害控制及生物多样性、土壤理化性质、稻田甲烷排放及控氮截流的影响,阐述了近年来稻鸭共作生态农业实施中投放绿萍、一稻两鸭、零日龄放鸭、沼稻鸭循环及防虫网全程覆盖等成功实践的种养模式,指出了稻鸭共作生态农业发展中亟待解决的问题,为稻鸭共作农作系统的技术理论和实践发展提供借鉴。 相似文献
19.
Idris I. Adejumobi Paterne A. Agre Adewumi S. Adeyinka Inacio M. Cipriano Joseph G. Adheka Didy O. Onautshu 《Plant Breeding》2023,142(5):563-572
Yam is an important tuber crop with enormous potential to enhance rural sustenance and livelihood in DRC. However, studies to enhance its genetic improvement are very far from sufficient with only a handful of information available on the crop. Yam has been treated as an orphan crop compared to contemporary crops such as cassava and sweet potato which have adapted to different cropping systems and become widespread in production. The lack of research attention to address the major production challenges has further decreased the value and potential of the crop compared to its contemporaries. These production constraints include lack of adequate quality planting materials, low yield potential, poor resistance/tolerance to yam mosaic and anthracnose diseases and ultimately poor tuber quality attributes focusing on tuber taste, flesh oxidation and dry matter contents of the majority of the farmers preferred varieties. In this review, we evaluated the status of yam in DRC and presented the needful activities to be incorporated for its improvement. Diversity has however been maintained mainly through ennoblement efforts in house gardens and small farmlands using traditional farming methods. Studies from other nations where yam has been successful with prominence in characterization and genetic improvement brought to light the need for DRC to consider yam as a staple carbohydrate food source, even to the extent of modifications in food public policy. Reversal of the yam's current stigma is a challenge to the scientific community and the population in general. 相似文献
20.
Challenging targets for future agriculture 总被引：9，自引：0，他引：9
This article points out the kinds of problems agriculture is facing, outlines and structures agricultural quality components and defined aims for them, discusses the shortcomings of organic farming, proposes some important research areas and presents an outlook. The quality components are a type of checklist of those factors that we should be aware of concerning protection of the environment, production of healthy food and the practice of good ethics. These components can be integrated into the general aims of sustainable agriculture. Many European and other countries focus on organic farming as a solution, but this approach is dangerous because it does not necessarily lead to a better environment or better food products. Concerning future agricultural research, the following issues are highly important: precision agriculture, low leaching cropping systems, management of soil biological processes and maximum recirculation. Finally, the article discusses some issues of future agriculture such as intensity, nutrient imbalances caused by regional farm specialisation, and the development of an agricultural quality assessment system. 相似文献