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.

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.

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.

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。

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.

Poverty alleviation through e-commerce:Village involvement and demonstration policies in rural China

The diffusion of e-commerce has played a significant role in recent rural economic development in China.E-commerce is also considered as an efficient channel to alleviate poverty in rural China.Voluminous studies have investigated the contribution of e-commerce to agricultural development,yet it is lacking empirical evidence as to the effects of e-commerce on rural poverty alleviation.Since the year of 2014,in order to develop rural e-commerce,Chinese government launched the National Rural E-commerce Comprehensive Demonstration Project.This gradual involvement policy offered a natural experiment for evaluation of e-commerce.Based on village-level survey data from rural China and Heckit method,our study finds that rural e-commerce has a significantly positive effect on rural income.Moreover,the effect is inverted U-shaped for the relative-poverty villages.The estimation of the propensity scores matching model confirms that the results are robust.The following policy recommendations are proposed:(1)policy support to rural e-commerce should prioritize the povertystricken villages.By doing so,the marginal income effects of e-commerce will be maximized.(2)Investment in internet infrastructure and establishment of human resources for e-commerce in rural areas will have spillover effects,increasing rural income through the"digital dividend".

Potential and Suitability Evaluation of CO_2 Geological Storage in Major Sedimentary Basins of China,and the Demonstration Project in Ordos Basin

From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey （CHEGS） carried out the project ＂Potential evaluation and demonstration project of CO2 Geological Storage in China＂. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2 geological storage based on China＇s geological conditions, and evaluated the potential and suitability of the primary basins for COz geological storage, in order to draw a series of regional scale maps （at a scale of 1：5000000） and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2 storage. We also built techniques and methods for site selection and the exploration and assessment of CO2 geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2 geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2 storage in deep saline aquifers under China＇s geological conditions.

Demonstration of a Sub-Sampling Phase Lock Loop Based Microwave Source for Reducing Dick Effect in Atomic Clocks

We demonstrate a simple scheme of 6.835 GHz microwave source based on the sub-sampling phase lock loop(PLL). A dielectric resonant oscillator of 6.8 GHz is directly phase locked to an ultra-low phase noise 100 MHz oven controlled crystal oscillator(OCXO) utilizing the sub-sampling PLL. Then the 6.8 GHz is mixed with 35 MHz from an direct digital synthesizer(DDS) which is also referenced to the 100 MHZ OCXO to generate the final6.835 GHz signal. Benefiting from the sub-sampling PLL, the processes of frequency multiplication, which are usually necessary in the development of a microwave source, are greatly simplified. The architecture of the microwave source is pretty simple. Correspondingly, its power consumption and cost are low. The absolute phase noises of the 6.835 GHz output signal are-47 d Bc/Hz,-77 dBc/Hz,-104 dBc/Hz and-121 dBc/Hz at1 Hz, 10 Hz, 100 Hz and 1 kHz offset frequencies, respectively. The frequency stability limited by the phase noise through the Dick effect is theoretically estimated to be better than 5.0 × 10^-14τ^1/2 when it is used as the local oscillator of the Rb atomic clocks. This low phase noise microwave source can also be used in other experiments of precision measurement physics.

Constructing demonstration zones to promote the implementation of Sustainable Development Goals

After the United Nations Agenda 2030 was officially launched in September 2015,governments around the world have taken actions to implement the ambitious plan.This paper summarizes the actions and policies taken in China for promoting the implementation of the UN’2030 Agenda for Sustainable Development,with emphasis on promoting the development of demonstration zones for delivery of the Sustainable Development Goals(SDGs).The Chinese government has taken two types of measures.One is to formulate a series of national plans and strategies and the other is to construct pilot and demonstration zones.Two approaches were presented to optimize the selection criteria for demonstration zones:a problem-based approach;and a major function-based approach.Both provided priority regions and major themes for selection and construction of demonstration zones.Suggestions for promoting the development of demonstration zones include:(1)building a monitoring system for the implementation of SDGs in each demonstration zone and establishing an open online platform to track the progress;(2)forming an effective stakeholder participation mechanism.The experiences in constructing innovation-driven demonstration zones are insightful for other countries to take practical actions in the delivery of SDGs.

Vehicle fuel from biogas with carbon membranes; a comparison between simulation predictions and actual field demonstration

The energy contents of biogas could be significantly enhanced by upgrading it to vehicle fuel quality.A pilot-scale separation plant based on carbon hollow fiber membranes for upgrading biogas to vehicle fuel quality was constructed and operated at the biogas plant,Gl?r IKS,Lillehammer Norway.Vehicle fuel quality according to Swedish legislation was successfully achieved in a single stage separation process.The raw biogas from anaerobic digestion of food waste contained 64±3 mol%CH_4,30–35 mol%CO_2 and less than one percent of N_2 and a minor amount of other impurities.The raw biogas was available at 1.03 bar with a maximum flow rate of 60 Nm^3h^(à1).Pre-treatment of biogas was performed to remove bulk H_2O and H_2S contents up to the required limits in the vehicle fuel before entering to membrane system.The membrane separation plant was designed to process 60 Nm^3h^(à1)of raw biogas at pressure up to 21 bar.The initial tests were,however,performed for the feed flow rate of 10 Nm^3h^(à1)at 21 bar.The successful operation of the pilot plant separation was continuously run for 192 h(8days).The CH_4 purity of 96%and maximum CH_4 recovery of 98%was reached in a short-term test of 5 h.The permeate stream contained over20 mol%CH_4which could be used for the heating application.Aspen Hysys~?was integrated with Chem Brane(in-house developed membrane model)to run the simulations for estimation of membrane area and energy requirement of the pilot plant.Cost estimation was performed based on simulation data and later compared with actual field results.

China has launched a deep gold prospecting demonstration project to evaluate gold resource potential within 3000 m underground in the east of the North China Craton

On October 18,2018,the China Geological Survey launched a project of the National Key Research and Development Program of China,entitled "Prediction and Deep Exploration Demonstration of Gold Polymetallic Deposits in the Jiaodong and Liaodong Areas within the North China Craton".For this project,Wulong and Baiyun- Xiaotongjiapuyi in Jiaodong,as well as the northern Zhaoping belts of Liaodong,were chosen as ore prospecting demonstration areas (Fig.1).

Planning and Ecological Greening of Agricultural Sci-Tech Ecological Demonstration Park in Suning County,Hebei Province

Taking the control detailed planning of Suning Agricultural Sci-Tech Ecological Demonstration Park in Hebei Province for example,general methods for the planning of modern agricultural sci-tech parks were introduced from the perspective of general situation of the planning area,technical routes,guiding concepts and planning principles,ecological greening and plant confi guration of the parks was discussed.

Comprehensive Evaluation on Demonstration Farmers' Specialized Cooperatives on the Basis of AHP Model

On the basis of AHP method,this paper establishes comprehensive evaluation model of demonstration farmers' specialized cooperatives,uses the Delphi method and AHP software to assign scientific and objective weight to 7 criteria in criteria layer and 27 indices in index layer,and evaluate the overall level of 153 farmers' specialized cooperatives whose main business is fruits and vegetables in Region R.The results show that the overall operation level of farmers' specialized cooperatives is common;democratic and financial management is open;the information-based level and social sensation are not insufficient;the marking results of questionnaire is basically scientific and objective.This paper discusses the new way to evaluate operation level of farmers' specialized cooperatives,and puts forward relevant countermeasures and suggestions as follows:promote the information-based level of demonstration cooperatives;strengthen the service capacity of demonstration cooperatives;use means of science and technology to promote product quality;amplify social sensation of farmers' specialized cooperatives.

Demonstration and Radiation Extension mode of Agricultural Technology——A Case of the Science and Technology Project of High Yield in Hebei Province

Firstly,relying on the science and technology project of high yield in Hebei Province,connotation of agricultural technology demonstration and extension mode and the high yield grain project in Hebei Province is introduced.Extension mode of agricultural technology demonstration and radiation is constructed.Agricultural technology demonstration and radiation mode includes the radiation center,primary irradiation and secondary irradiation.Secondly,management system and operational mechanism of agricultural technology demonstration and radiation mode are discussed,mainly expressed in establishing leading group in each demonstration county(city),carrying out leader contract responsibility system,establishing expert advisor steering group and setting up core experts group for subject,establishing technical experts group for subject,setting up leading group in the radiation area,carrying out chief expert responsibility system and technician matrix responsibility system,establishing the operating mechanism of "open,flow,competition and collaboration" with "test area-expert two-way selection" as the core content.Finally,countermeasures to improve the agricultural technology demonstration and radiation mode is put forward,such as establishing the rural technology demonstration base,strengthening cooperation with enterprises,and adopting flexible technical training,so as to promote the spread of agricultural high-tech,to increase the contribution rate of agricultural technology,and to offer ideas for agricultural technology extension model at the new era.

R&D and Demonstration of Large Domestic CFB Boilers

In order to develop large CFB boilers with independent intellectual property, Xi'an Thermal Power Research Institute (TPRI) established a laboratory with complete functions for the technical development of CFB boilers. This laboratory consists of a 1-MW and a 4-MW CFB combustion test facilities and a laboratory for limestone desulphurization performance evaluation. It carried out tests on CFB combustion and desulphurization for Chinese typical coals and limestone and research on heat-transfer characteristics and key parts, and developed the first home-made 100-MW CFB boiler. Based on the experience of R&D, the laboratory further researched key techniques for enlarging capacity systematically, and cooperating with Harbin Boiler Co. (HBC), developed the first domestic 210-MW CFB boiler with independent intellectual property and put it into engineering demonstration, laying a solid foundation for the development of CFB boilers of even larger capacity.