Ground demonstration system based on in-orbit assembly oriented manipulator flexible force control

To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.

Construction of the Demonstration Area for the Inheritance and Development of Yimeng Red Culture Based on Digital Empowerment

Yimeng red culture is an important part of the excellent culture of the Chinese nation.It is of great practical significance and long-term strategic significance to build the demonstration area for the inheritance and development of Yimeng red culture.Combining digital empowerment with the inheritance and development of Yimeng red culture is a new idea that conforms to the development of the times.In this paper,on the basis of combing Yimeng red cultural resources and combining with the current situation of inheritance and development of Yimeng red culture,the strategic layout and implementation approach of the demonstration area for the inheritance and development of Yimeng red culture were put forward from the perspective of digital empowerment.

Construction and Development of the National Experimental Teaching Demonstration Center for Drama and Film and Television Disciplines

Taking the National Experimental Teaching Demonstration Center of the Central Academy of Drama as an example,this article explores the construction and development of the National Experimental Teaching Demonstration Center for the practical teaching of drama and film and television disciplines.The article first introduces the background and importance of the demonstration center and then analyzes in depth the construction content and achievements of the demonstration center from four aspects:practical teaching philosophy,practical teaching system,practical teaching resources,and practical teaching effects.Finally,the article summarizes the experience and shortcomings of the demonstration center and proposes future development directions and suggestions.

Progress and performance evaluation of Bei Dou global navigation satellite system： Data analysis based on BDS-3 demonstration system

The first two Medium Earth Orbit(MEO) satellites of the third generation of Bei Dou satellite navigation System(BDS-3) were successfully launched on November 5, 2017. This historical launch starts the new era of the global navigation satellite system of Bei Dou. Before the first two satellites of BDS-3, a demonstration system for BDS-3 with five satellites,including two Inclined Geosynchronous Orbit satellites(IGSO) and three MEO satellites, was established between 2015 and2016 for testing the new payloads, new designed signals and new techniques. In the demonstration system, the new S frequency signal and satellite hydrogen clock as well as inter-satellite link(ISL) based on Ka-band signals with time-division multiple addresses(TDMA) were tested. This paper mainly analyzes the performances of the demonstration system, including the signalto-noise ratios, pseudorange errors and the multipath errors of the civilian signals of BDS-3. The qualities of signals in space,time synchronization and timing precision were tested as well. Most of the performances were compared with those of the regional Bei Dou satellite navigation system(BDS-2). At last, the performances of positioning, navigation and timing(PNT) of the future Bei Dou global system(BDS-3) were evaluated based on the signal quality of the present demonstration satellite system.

Rural sustainable development:A case study of the Zaozhuang Innovation Demonstration Zone in China

Sustainable development is the central theme of modern global development.With the arrival of the urban era,the vulnerability and instability of rural areas have significantly increased,and rural sustainable development faces serious challenges.To address these issues,the study took the Zaozhuang Innovation Demonstration Zone in China under the National Sustainable Development Agenda as a case,combined with economic,social and land use data during 2016-2020,and applied Granger causality test method to explore the theoretical and practical pathways of“innovation-driven rural sustainable development”.The results showed that rural sustainable development and economic sustainability displayed a trend of synergistic change,with“explosive”growth from 2018 to 2020.The social sustainability steadily increased from 2016 to 2020.Ecological and spatial sustainability continuously declined during the study period.Moreover,the rural innovation capacity of the Zaozhuang Innovation Demonstration Zone displayed rapid growth during 2016-2020.Although the rural innovation capacity of the Zaozhuang Innovation Demonstration Zone has rapidly improved,it has a weak driving effect on rural sustainable development and economic sustainability.There are two primary challenges that must be overcome to ensure the rural sustainable development of the Zaozhuang Innovation Demonstration Zone.The first challenge is the imbalance among the multi-dimensional relationships in the process of rural sustainable development,and the second challenge is the weakening of rural innovation capacity to drive rural sustainable development.To overcome these challenges,this study proposed a systematic pathway for rural sustainable development in the Zaozhuang Innovation Demonstration Zone from multidimensions,such as policy actions,technologies,projects,and institutional guarantees,and formed a universal and representative“Zaozhuang model”.This study expands the theoretical foundation of rural sustainable development and provides theoretical and practical support for innovation-driven rural sustainable development.

Clustering-based maintainability demonstration for complex systems with a mixed maintenance time distribution

During maintainability demonstration,the maintenance time for complex systems consisting of mixed technologies generally conforms to a mixture distribution.However existing maintainability standards and guidance do not explain explicitly how to deal with this situation.This paper develops a comprehensive maintainability demonstration method for complex systems with a mixed maintenance time distribution.First of all,a K-means algorithm and an expectation-maximization(EM)algorithm are used to partition the maintenance time data for all possible clusters.The Bayesian information criterion(BIC)is then used to choose the optimal model.After this,the clustering results for equipment are obtained according to their degree of membership.The degree of similarity for the maintainability of different kinds of equipment is then determined using the projection method.By using a Bootstrap method,the prior distribution is obtained from the maintenance time data for the most similar equipment.Then,a test method based on Bayesian theory is outlined for the maintainability demonstration.Finally,the viability of the proposed approach is illustrated by means of an example.

A New Reward System Based on Human Demonstrations for Hard Exploration Games

The main idea of reinforcement learning is evaluating the chosen action depending on the current reward.According to this concept,many algorithms achieved proper performance on classic Atari 2600 games.The main challenge is when the reward is sparse or missing.Such environments are complex exploration environments likeMontezuma’s Revenge,Pitfall,and Private Eye games.Approaches built to deal with such challenges were very demanding.This work introduced a different reward system that enables the simple classical algorithm to learn fast and achieve high performance in hard exploration environments.Moreover,we added some simple enhancements to several hyperparameters,such as the number of actions and the sampling ratio that helped improve performance.We include the extra reward within the human demonstrations.After that,we used Prioritized Double Deep Q-Networks(Prioritized DDQN)to learning from these demonstrations.Our approach enabled the Prioritized DDQNwith a short learning time to finish the first level of Montezuma’s Revenge game and to perform well in both Pitfall and Private Eye.We used the same games to compare our results with several baselines,such as the Rainbow and Deep Q-learning from demonstrations(DQfD)algorithm.The results showed that the new rewards system enabled Prioritized DDQN to out-perform the baselines in the hard exploration games with short learning time.

Research and Demonstration of Direct Air-Cooling System for 600-MW Fossil-Fired Power Plants

Given the distribution feature of resources such as coal and water, the requirements for the development of Chinese power industry, and the fact of monopoly by foreign companies, it is very necessary and significant to independently research and develop air-cooling technologies. Through experimental research, simulative calculation, process and equipment development, field tests and a demonstration project, the design and operation technologies for air-cooling system are grasped and relevant key equipment is developed. The results of the demonstration project show that the technical indicators for the air-cooling system have met or exceeded the design requirements. Part of the research results have been incorporated into the relevant national design standards. The technologies developed have been applied to more than 23 sets of thermal power units of or above 600 MW in China.

Evaluation of Women’s Contribution in Agroforestry Demonstration through Moringa Species Introduction in Western Oromia,Ethiopia

Agroforestry technologies are very keen practices in most small-scale farming systems where gender issues are not well considered in most developing countries.Moringa is a tropical plant that consists of 13 species,while five of them are found in Ethiopia.This study aimed to evaluate the potential and contribution of women in agroforestry demonstrations where Moringa oleifera and Moringa stenopetala are introduced in farmers’fields.Selection of the best performing moringa species and preferred by farmers for further scaling up was also another objective.The activity was conducted in five districts of west and east Wallagga zones.A total of 10 FREG comprising 150 farmers were established.The two moringa species were planted on 100 farmers’fields where 50 women and 50 men were purposively selected and given responsibilities of moringa demonstration.Leaflets and practical training on moringa production,importance and utilization were prepared and given to all concerned bodies.84%of women and only 32%of men effectively demonstrated the moringa species.A total of 200 farmers were interviewed to evaluate and select the best from the two species depending on their growth performance,fresh leaf taste and odor,and survival rate.Based on the above criteria,143(71.5%)farmers preferred Moringa oleifera.In general,the two moringa species were performed well in most places,and its utilization started at household level.Finally,the authors recommend that women are the potential for demonstrating agroforestry technologies,and Moringa oleifera is a more preferred species in western Oromia.

Research on the Strategy of Promoting Daqing to Create a National Public Employment and Entrepreneurship Service Demonstration City

Based on the research on the basic status quo of the construction of public employment and entrepreneurship service system in Daqing, this paper analyzes the problems existing in Daqing’s establishment of a national public employment and entrepreneurship service demonstration city, and gives countermeasures and suggestions from three levels: optimizing the public employment and entrepreneurship service system, innovating the public employment and entrepreneurship service mode, and improving the entrepreneurship driven employment support system.

Plan and Practice of Ecological and Leisure Agricultural Demonstration Park ——A case of Xiangtian Village in Jin'an County

With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteristic and promising plan of the park was proposed.

Are cities greener because of innovation?Independent innovation policy and green economic efficiency

The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future.

Research of Ecological Restoration of Jari Agricultural Demonstration Site in Ethiopia

In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.

Planning of Modern Agricultural Demonstration Zone from the Perspective of Industrial Convergence——Also Study on the Expansion of Its Tourist Functions

Features of agritourism emerging in the development of modern agriculture were analyzed, it was stressed that industrial convergence was a basic feature of modern agriculture, and modern agriculture was the integration of agriculture, science and technology, integration of agriculture, industry and trade, and integration of rural and urban areas. Agritourism was believed as the optimal carrier of expanding functions of modern agriculture combining agriculture, ecology and tourism industry. From such perspectives, causes for the loss of tourist functions in the development of agricultural demonstration zone were identified as 5 aspects, specifically including various planners from diverse fields; no any technical standard for the planning, or systematic planning theory and technique; many individual planning cases with poor applicability; no innovative idea brought into the tourism project planning; the loss of cultures in new tourist products. After proposing key points in the expansion planning of tourist functions, this research pointed out 4 countermeasures, i.e. (1) design concepts should be changed; (2) planning functions should be reoriented to match service facility planning with laws of tourism development and properly design tourist projects; (3) landscaping planning should be focused on; and (4) eco-environment protection and brand building should be enhanced.

A New Proof for Congruent Number’s Problem via Pythagorician Divisors

Considering Pythagorician divisors theory which leads to a new parameterization, for Pythagorician triplets ( a,b,c )∈ ℕ 3∗ , we give a new proof of the well-known problem of these particular squareless numbers n∈ ℕ ∗ , called congruent numbers, characterized by the fact that there exists a right-angled triangle with rational sides: ( A α ) 2 + ( B β ) 2 = ( C γ ) 2 , such that its area Δ= 1 2 A α B β =n;or in an equivalent way, to that of the existence of numbers U 2 , V 2 , W 2 ∈ ℚ 2∗ that are in an arithmetic progression of reason n;Problem equivalent to the existence of: ( a,b,c )∈ ℕ 3∗ prime in pairs, and f∈ ℕ ∗ , such that: ( a−b 2f ) 2 , ( c 2f ) 2 , ( a+b 2f ) 2 are in an arithmetic progression of reason n;And this problem is also equivalent to that of the existence of a non-trivial primitive integer right-angled triangle: a 2 + b 2 = c 2 , such that its area Δ= 1 2 ab=n f 2 , where f∈ ℕ ∗ , and this last equation can be written as follows, when using Pythagorician divisors: (1) Δ= 1 2 ab= 2 S−1 d e ¯ ( d+ 2 S−1 e ¯ )( d+ 2 S e ¯ )=n f 2;Where ( d, e ¯ )∈ ( 2ℕ+1 ) 2 such that gcd( d, e ¯ )=1 and S∈ ℕ ∗ , where 2 S−1 , d, e ¯ , d+ 2 S−1 e ¯ , d+ 2 S e ¯ , are pairwise prime quantities (these parameters are coming from Pythagorician divisors). When n=1 , it is the case of the famous impossible problem of the integer right-angled triangle area to be a square, solved by Fermat at his time, by his famous method of infinite descent. We propose in this article a new direct proof for the numbers n=1 (resp. n=2 ) to be non-congruent numbers, based on an particular induction method of resolution of Equation (1) (note that this method is efficient too for general case of prime numbers n=p≡a ( ( mod8 ) , gcd( a,8 )=1 ). To prove it, we use a classical proof by induction on k , that shows the non-solvability property of any of the following systems ( t=0 , corresponding to case n=1 (resp. t=1 , corresponding to case n=2 )): ( Ξ t,k ){ X 2 + 2 t ( 2 k Y ) 2 = Z 2 X 2 + 2 t+1 ( 2 k Y ) 2 = T 2 , where k∈ℕ;and solutions ( X,Y,Z,T )=( D k , E k , f k , f ′ k )∈ ( 2ℕ+1 ) 4 , are given in pairwise prime numbers.2020-Mathematics Subject Classification 11A05-11A07-11A41-11A51-11D09-11D25-11D41-11D72-11D79-11E25 .

Public Speaking的技巧与策略(9)——如何进行Demonstration Presentation

你也许经常听到有人问你“做给我看看好吗?”我们几乎都是在演示过程中学会做每件事的。有时这种演示是正式的,比如在工厂或某种技术培训时。在其它情况下的演示则为非正式的。在演示过程中,我们通过观察和提问来学习,最后自己动手做某件事。教别人做事的过程就是一个演示过程,演示性演讲用途广泛,因此,对我们每个人来说都很重要。掌握了演示性演讲的技巧。

Selection of Tree and Shrub Species for Ecological Recovery in Jari Demonstration Plot in Ethiopia

Environmental degradation and deforestation in Jari Demonstration Plot needed forestation and reforestation,and the plant species selection was a key issue in the ecological recovery.Ecological information was fully considered regarding each species in various agro-climatic zones,altitude ranges,specific niches in different landscapes,soil preference,drought resistance and certain other important ecological factors.The species selection model represents an idea of ecological recovery and soil erosion control in the demonstration plot.

Problem and Countermeasure Analysis of Popularization Mode for Rural Residential Demonstration Project

Popularization mode of government-dominated rural residential demonstration projects and its features were introduced.It was proposed that such a popularization mode still remained at the primary development stage and was still suffering from many problems such as guiding role of government not fully played,lack of assessment standards,unitary funding channels,ineffective popularization effects and unpractical management regulations.In view of these problems,popularization strategies for rural residential demonstration projects were given from the perspective of establishing authorized coordination and supervision agencies,improving incentive policies of demonstration projects and also regulation system for these projects,expanding funding channels,and building information platforms.The study was to provide practical references for the future development of rural residential demonstration projects.

Examining the Experiences and Challenges of Haze-Fog Governance in China

With the rapid development of industrialisation and urbanisation, China is facing the challenge of severe HF (Haze-Fog) pollution. This essay compares the advantages and disadvantages of China’s HF management and summarizes the important lessons China can teach the rest of the world about applying this tactic. China’s capabilities in the digital economy, National Innovation Demonstration Zones, and urban innovation systems are examined in this article, along with its shortcomings in information mechanisms and pollution sources. This essay also summarizes China’s achievements, particularly regarding local autonomy. The essay goes on to say, however, that China is probably going to be under more pressure to manage HF in the future, both in terms of long-term solutions and the economy.

Fields of Promise

Burundi and China enjoy close collaboration in a number of sectors,particularly agriculture.Among the major initiatives,the introduction of hybrid rice cultivation stands out as a flagship project.In 2018,the first demonstration village for hybrid rice cultivation was established in the commune of Gihanga in northwestern Burundi.In 2020,this initiative reached a crucial stage with the creation of the Burundi Agricultural Pilot Centre(APC),located in Gihanga in the province of Bubanza.A total of 56 villages spread across 11 of Burundi’s 18 provinces have been selected for demonstration as of now.Yang Huade,head of the team of high-level Chinese agricultural experts supporting Burundi and a rice cultivation specialist who is also in charge of the APC,revealed that trials are currently underway in four provinces:the capital Gitega,the central province of Muramvya,and the northern provinces of Ngozi and Kayanza.