Functional Sustainability of a Flight Dynamics Control System for Stable Hovering Flight of an Unmanned Aerial Vehicle(UAV),such as in Agricultural Applications:Mathematical Modeling and Simulation

The simulation of a control system for the longitudinal axis of the rotary or fixed-wing unmanned aerial vehicles(UAVs)is demonstrated in this study.The control unit includes design considerations of two controllers to provide robust stability,tracking of the proposed linear dynamics,an adequate set of proportional-integral-derivative(PID)controller gains,and a minimal cost function.The PID control and linear quadratic regulator(LQR)with or without full-state-observer were evaluated.An optimal control system is assumed to provide fast rise and settling time,minimize overshoot,and eliminate the steady-state error.The effectiveness of this approach was verified by a linear model of the UAV aircraft in the semi-dynamic simulation platform of Matlab/Simulink,in which the open-loop system was assessed in terms of flight robustness and reference tracking.The experimental results show that the proposed controllers effectively improve the configuration of the control system of the plant,maintain the sustainability of the dynamic flight model stability,and diminish the flight controller errors.The LQR provides robust stability,but it is not optimal in the transient phase of particular plant output.The PID control system can adjust the controller’s gains for optimal hovering(or stable slow flight)and is especially useful for the tracking system.Finally,comparing aircraft stability using PID and LQR controllers shows that the latter has less overshoot and a shorter settling time;in addition,all proposed controllers can be practically deployed as one UAV’s system,which can be handled as an exemplary model of the UAV flight management system.

Agricultural Development Mode Transformation and Government Functions in Guizhou Province

Based on the brief account of the connotation of transforming economic development pattern and government functions,the thesis will introduce the development status of agricultural economy in Guizhou Province:firstly,single agricultural industrial structure;secondly,large gap between urban and rural development;thirdly,low-level utilization of agricultural science and technology;fourthly,fierce contradiction between agricultural mode of production and ecological environment.Then it analyzes the basic requirements for government functions in transforming the development pattern of agricultural economy in Guizhou Province:the first one is the function to guide sustainable development and the structural adjustment of agricultural production;the second is the function to coordinate urban-rural development and equally supply basic public goods;the third is the function to input science and technology to serve agriculture;the fourth one is the dominant function to promote the harmonious development of man and nature as well as to reduce the number of peasants.In order to promote the transformation of agricultural development mode and maintain the sound and rapid economic development,some corresponding measures and suggestions are proposed from the perspective of government functions:firstly,promoting the optimization and upgrading of industrial structure;secondly,the government should take the lead in providing rural public goods;thirdly,strengthening the skills training and technological education of rural labor force;fourthly,reducing the number of farmers and retaining the farmers.

Study on the Functional Division of Agricultural Sightseeing in Handan City

Agricultural sightseeing in a new tourism pattern integrates ecological tourism functions into ecological agriculture and rural cultures. Handan City is located in southern Henan Province with excellent geographical conditions. In 2006-2008, agricultural sightseeing has achieved primary development in Handan City, and gradually become an indispensable component of the tourism market in this city. Promoting agricultural sightseeing in Handan City as well as the upgrading of its agriculture will be enhanced, which can be transformed from traditional and unitary function into the comprehensive functions of production, ecology, tourism, culture and education, thus is favorable for promoting the further development of tourism industry, enriching tourism products, realizing the sustainable development of agricultural tourism. Besides, surplus rural labors will be offered more opportunities, and industrial structure in rural areas will also be adjusted properly. Through dividing agricultural sightseeing in Handan City into the eco-agricultural sightseeing zone in the west, metropolis agricultural sightseeing zone in the middle, and economic agricultural sightseeing in the east, the authors clearly defined their ranges, orientation of typical functions, dominant development modes as well as projects, so as to figure out the reasonable development pattern for agricultural sightseeing in Handan City, specify its development context, and provide theoretical basis for the future development of agricultural sightseeing in this city.

Propagation characteristics from meteorological drought to agricultural drought over the Heihe River Basin, Northwest China

In the context of global warming,drought events occur frequently.In order to better understanding the process and mechanism of drought occurrence and evolution,scholars have dedicated much attention on drought propagation,mainly focusing on drought propagation time and propagation probability.However,there are relatively few studies on the sensitivities of drought propagation to seasons and drought levels.Therefore,we took the Heihe River Basin(HRB)of Northwest China as the case study area to quantify the propagation time and propagation probability from meteorological drought to agricultural drought during the period of 1981–2020,and subsequently explore their sensitivities to seasons(irrigation and non-irrigation seasons)and drought levels.The correlation coefficient method and Copula-based interval conditional probability model were employed to determine the drought propagation time and propagation probability.The results determined the average drought propagation time as 8 months in the whole basin,which was reduced by 2 months(i.e.,6 months)on average during the irrigation season and prolonged by 2 months(i.e.,10 months)during the non-irrigation season.Propagation probability was sensitive to both seasons and drought levels,and the sensitivities had noticeable spatial differences in the whole basin.The propagation probability of agricultural drought at different levels generally increased with the meteorological drought levels for the upstream,midstream,and southern downstream regions of the HRB.Lesser agricultural droughts were more likely to be triggered during the irrigation season,while severer agricultural droughts were occurred mostly during the non-irrigation season.The research results are helpful to understand the characteristics of drought propagation and provide a scientific basis for the prevention and control of droughts.This study is of great significance for the rational planning of local water resources and maintaining good ecological environment in the HRB.

New Approach for China's Agricultural Modernization Practice from the Perspective of Multiplex Function

This paper analyzes the multiplex composite function of agriculture comprehensively as follows.The first is political function:it can ensure the national food security;the second is economic function:it can promote agricultural competitiveness and increase farmers' income;the third is social function:it can promote the construction of new socialist village;the fourth is ecological function:it can conserve the resources environment and guarantee sustainable development of agriculture.In terms of reference of international theory and the main innovative experience of domestic agricultural modernization practice,this paper points out the new approach for agricultural modernization practice in China,and puts forward institutional guarantee based on agricultural multiplex function as follows:we should gradually promote new land system taking land transfer as major content;we should establish rational transfer system of rural labour forces;we should establish virtuous circular agricultural financial credit system;we should hew to the innovation and promotion system of agricultural technology;we should establish strict the system of resources environment and ecological protection;we should establish the agricultural risk security system.

Function of Agricultural Land Use and Its Evolvement in Peri-urban Area: A Case Study of Beijing

Rapid urbanization in Beijing stimulates the urban land expansion and diminishes available agricultural land. Monofunctional agricultural land use can not meet the demand of the devel- opment of the multifunctional agriculture and urbanization any more, so multifunctional agricultural land use is going to be promoted in the city. This article proposes the evolvement of the land use change from 1992 to 2004 and discusses some evolvement views.

Path Analysis of Agricultural Project Design Based on Function Expansion: A Case Study of Naya Mountain Villa

The expansion of agricultural function is one of the important means for modern agricultural projects to promote agricultural economic benefits. Successful modern agricultural projects require good creative ideas and design programs. While developing high-efficient modern agricultural production activities,we should fully explore the intangible value of agricultural production activities,combine agriculture with agricultural products,natural conditions,cultural conception and other effective resources,to expand agricultural functions,and promote comprehensive benefits. In order to build a sustainable modern agricultural project operation system,Naya Mountain Villa project planning is taken as an example for analysis. Naya Mountain Villa began construction in 2011; the creative planning based on the agricultural expansion function was carried out in 2013; it had successful access to the capital market in 2015. The project realizes the effective integration of agricultural production system and agricultural function expansion,constructs a set of long-term stable profiting models,and lays an important foundation for entering the capital market. The project is a representative example of the function-expanding modern agricultural project. Through the analysis of the design ideas of the project,this paper discusses the function expansion elements of basic resources,public welfare and agricultural function expansion methods,the formation of general ideas,source and construction logic of creative thinking,and summarizes and abstracts some inspiring design methods of agricultural function expansion. Through the analysis of the key points in the design of the specific technical aspects of the project,this paper provides a reference for solving common difficult problems in the practical design. The summary and refinement of the thinking logic,thinking construction and specific design method of the project is inspiring and repeatable to some extent,which can provide reference for the relevant researchers.

Analysis on Function Orientation and Development Countermeasures of New Agricultural Business Entities

Along with the rapid advance of industrialization and urbanization process, fostering new agricultural business entities become inevitable for agricultural transformation and the construction of agricultural modernization in China. The status of the new agricultural business entities determines the level of modern agricultural development. In recent years, new agricultural business entities have grew rapidly. However, there are still many problems including the difficulties in financing loans, inadequate agricultural insurance system, bad implementation of agricultural subsidies, jagged agricultural talents and so on. In order to foster new agricultural business entities, countermeasures should be carried out to ensure financial support, perfect the agricultural insurance, strengthen the level of agricultural subsidies, strive to develop the degree of specialization agricultural operators and so on.

On the Government Function Orientation in China's Agricultural Management Reform

Since the reform and opening up,China's market-oriented agricultural management reform has achieved remarkable results,but the reform has not yet been put in place,and there are some flaws in some areas of reform.To deepen the reform of government's agricultural management reform under the new situation,it is necessary to further define the boundary between government and market on the basis of following the general rules of world's agricultural development and considering China's special situation of agriculture,nail down the scope of government functions,pinpoint the key areas of reform,and actively promote the rapid development of China's characteristic modern agriculture.

The Estimation Methods for Agricultural Surplus Labor Based on Stochastic Frontier Production Function

The existing calculation methods for the number of agricultural surplus labor have a common flaw,that is,they can not reflect the impact of technical efficiency changes in agricultural production on the surplus labor. Based on the basic principle of stochastic frontier production function,this paper calculates the agricultural production technical efficiency of various provinces,and selects the province with the highest technical efficiency to assume that its agricultural labor is fully utilized,and there is no agricultural surplus labor. With the ratio of agricultural labor number to agricultural output value in this province as a reference,this paper calculates the number of agricultural surplus labor in other provinces. This calculation method makes up for the shortcomings of the existing calculation methods; it reflects the relationship between the number of agricultural surplus labor and production technical efficiency.

Industrial Policy Analysis of Restricted Development Zones in Western China——A Study of State-level Main Producing Areas of Agricultural Products and Key Ecological Functional Areas

As one of the important policies of promoting the formation of main functional areas, the industrial policy directly determines the sustainable growth of space control ability of main functional areas. A restricted development zone is a type of main functional area which provides agricultural products and ecological products, assures the supply of national agricultural products and the stability of ecosystems, as well as safeguards the ecological functions and agricultural functions of wider regions by restricting its own development. Therefore scientific, complete and operable industrial policy support is needed. Restricted development zones are distributed widely in western China. With the restriction of their main functions, differential industrial policies should be implemented in the development of the restricted development zones: Dealing well with the relationship between industrial development and ecological protection, developing special industries which are friendly to resources and environment and appropriate for local conditions, guiding and encouraging industries to learn from regions with favorable development conditions, orderly withdrawing industries and enterprises adverse to main functions, facilitating industrial structure upgrading, optimizing industrial organization, improving industrial technological level and rationalizing industrial layout.

Agricultural Multifunctionality Evolution and Research into Issues concerning Agriculture,Countryside and Farmers

From the point of view of agricultural civilization, the history of human civilization is the history of the development of the agricultural civilization. Accompanied by social progress and development of the times, the function of agriculture also experiences the expansion and deepening. In terms of economy, there is a process from mechanized farming to industrialization, then to informatization, modernization and internationalization. The great rejuvenation of the Chinese nation has also experienced and witnessed this process. In terms of "agriculture, countryside and farmers", the content is complex, diverse, profound, sharp, and changing, constantly testing and challenging our wisdom. When the Document No.1 in 2007 targeted modern agriculture, it indicated that new connotation was integrated into agricultural multifunctionality, standing at a new starting point. At present, the function of agriculture is still deepening; there are tremendous achievements and outstanding problems concurrently in issues concerning agriculture, countryside and farmers. We take the agricultural multifunctionality as breakthrough point for exploration and research.

Discussion on Structure Evolution and Function Expansion of Agriculture in China

According to the characteristics of agricultural development during different periods, agricultural development was basically divided into traditional period, planning system period and household contracting pedod to discuss the related laws of agricultural development in China. The agricultural function expansion during different periods was analyzed in terms of agricultural structure evolution, while structural optimization and function expansion of modem agriculture in China were also studied. The results indicated that during the traditional period, agricultural structure emphasized feeding people and grain production while agricultural function reflected the economic function beyond surviving standard. During the planning system period, a unitary structural mode of agriculture was formed in China, which showed that agriculture was dominated by planting industry and planting industry was dominated by grain, while agriculture executed the mixed economic function beyond surviving and liv- ing standard. During the household contracting period, the industrial structure of agriculture in China gradually became diversification and optimi- zation, but as the economic function of industrial standard, agricultural development was still greatly inhibited. The structural evolution of modem agriculture in China must step forward towards collectivization and scale merit, while ecological function and social function of agriculture increas- ingly become important and the function of agricultural production becomes mere and more diverse.

Agriculture Development in Agriculture Oriented County Based on Territorial Function ——A Case Study of Long’an County in GuangXi Zhuang Autonomous Region

[Objective] The aim was to research development plan of major agriculture-oriented county （MAOA or MAOC hereafter） based on territorial function. [Method] The relationship between Major Function Oriented Zoning （MFOZ hereafter） and agricultural development is explored with the case of Long＇an County in Guangxi. [Result] In the research, agricultural function, featured by composition and diversification, is considered one of territorial function typs, contributed by ecology, land, industries and population. With Long＇an as a study case, it can be concluded that the plan of major agriculture-oriented counties is as follows： With guidance of territorial function, the counties should formulate the strategies of major function oriented zones, strive for more social and economic resources for agricultural development, extend agricultural functions, enhance the role of agricultural additional functions, strengthen ecological conservation, improve agricultural productivity and transportation, reinforce exchange of countryside with other regions. In addition, attention should be paid to reconstruction of population and industry pattern for redistribution on the basis of evaluation on bearing capacity of resources and environment. [Conclusion] In future, major agriculture oriented county should coordinate relationship among agriculture, industries, ecology and population with rational distribution of territorial function in county to guarantee stable and sustainable agricultural development.

Study on Decision Support System of Agricultural Sustainable Development of Jianli County in Jianghan Plain

With the agricultural development and the modernization of decision-making, it is necessary to establish the agricultural sustainable development decision support system supported by GIS. We set Jianli county as an example; our aim is to realize decision spatialiazation with the support of information system, remote sensing and artificial intelligence. The system components are described in the aspects of database, knowledge base, model-base and method-base. This system will provide a workable system for local decision-makers and agricultural management sections.

Operation Mode and Optimum Design of China's Agricultural Modern Logistics System

Using comparative analysis and logical reasoning methods,in combination with traditional logistics theory and practice,and on the basis of objective demand of modern agricultural development for logistics service,we analyze features of logistics function.Besides,we discuss functional elements and service contents of agricultural modern logistics.In addition,we explore innovation model of agricultural modern logistics and systematized operation of supply chain.Finally,it is concluded that logistics development shall bring into full play all functional elements and achieve high efficient operation of the system through enhanced management measures.

Pathways for Expediting Joint Agricultural Development of China and BRI Countries

Based on the agricultural panel data of 107 countries from 1962 to 2016,this paper establishes a global agricultural spatial production model,and explores pathways for mutually beneficial cooperation between China and the Belt and Road Initiative(BRI)countries in the agricultural sector.As shown in the empirical results,two-way spillover effects between China and BRI countries are all positive and significantly above world average of its kind,which builds the foundation of cooperation between both sides and reflects the BRI’s vision and foresight.In the context of the BRI,there are two pathways for expediting agricultural development in China and BRI countries:First,both sides may benefit from greater spillover effects from each other’s agricultural growth by promoting agricultural trade;second,China may gain from the overall spillover effects from agricultural development in BRI countries by promoting two-way trade,agri-technology aid and assistance in infrastructure projects for the common good of humanity.

Study on Planning and Design Mode of Eco-agricultural Demonstration Base in Poyang Lake Eco-economic Zone

Guided by the Planning of Poyang Lake Eco-economic Zone, traffic and geographic conditions of the Eco-agricultural Demonstration Base in the study area were analyzed, and design principles proposed as "adaptation to local conditions, scientific planning, benign circulation and sustainable development". Detailed planning and design was interpreted from the perspectives of infrastructure planning and functional area planning. Specifically, infrastructure construction should focus on traffic design, water, power and gas supply design, and also architectural design; while functional areas should be gradually developed from south section to central and then north section. It was to establish a design and planning mode that can be widely applied.

Empirical Analysis on Factors Restricting Low-carbon Agricultural Development in Hubei Province

From the perspective of input into agricultural production, the growth of agricultural production from 1982 to 2010 in Hubei Province was analyzed by using multiple regression method. The results show that the quantity of fertilizer and the total power of machinery used for farming have significantly contributed to agricultural growth in Hubei Province, but they are also main factors restricting low-carbon agricultural development in Hubei Province. Therefore, the key point to develop low-carbon agriculture in Hubei Province currently should be put on how to fertilize rationally, how to innovate the pattern of agricultural production, how to develop agricultural mechanization rationally and so on.

Recommendations for Sustainable Development of Selenium-enriched Functional Agriculture in Guangxi under the New Normal

Taking Scientific Outlook on Development as the guiding principle,this paper introduced the principles of innovation,coordination,green,openness and sharing. Based on gifted advantages of selenium-enriched soil and selenium-enriched industry development in Guangxi,it discussed current practice,stressed green,ecological,characteristic demonstration,transformation and upgrading,and targeted poverty alleviation. Finally,it came up with perspective,practical,and operational strategies and recommendations for development of selenium-enriched industry,to provide reference for sustainable development of selenium-enriched functional industry in Guangxi.