Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied extensively.Labor migration in rural China has taken new forms in recent years.There has been a di...Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied extensively.Labor migration in rural China has taken new forms in recent years.There has been a discernible trend wherein adult children have started migrating to cities while their elderly parents return to villages to re-engage in on-farm work.The phenomenon has notably shaped the intergenerational division of labor(IDL)within households.However,it remains to be seen how farmers adjust their rice production systems in response to the IDL.The age of 60 years for employment injury insurance is the eligibility threshold for off-farm employment and is used to obtain a source of exogenous variation in the IDL.Based on a representative household survey of 1,752 rice farmers in the Hubei Province of Central China,our fuzzy regression discontinuity analysis reveals that farmers in IDL households are more likely to adopt ratoon rice(RR)than single cropping rice(SR)or double cropping rice(DR).The effect of the IDL varies under different levels of operational scales and specialized agricultural service availability.Further analysis suggests that farmers’arrangements are associated with two potential mechanisms of downward intergenerational transfer.Monetary transfer for urban housing purchases increases RR in IDL households,and time transfer for intergenerational childcare significantly promotes SR in IDL households.This study enhances the understanding of the relationship between rural labor migration and rice production in China,providing a reference for adjusting rice production systems to ensure food security.展开更多
With the concepts of Industry 4.0 and smart manufacturing gaining popularity,there is a growing notion that conventional manufacturing will witness a transition toward a new paradigm,targeting innovation,automation,be...With the concepts of Industry 4.0 and smart manufacturing gaining popularity,there is a growing notion that conventional manufacturing will witness a transition toward a new paradigm,targeting innovation,automation,better response to customer needs,and intelligent systems.Within this context,this review focuses on the concept of cyber–physical production system(CPPS)and presents a holistic perspective on the role of the CPPS in three key and essential drivers of this transformation:data-driven manufacturing,decentralized manufacturing,and integrated blockchains for data security.The paper aims to connect these three aspects of smart manufacturing and proposes that through the application of data-driven modeling,CPPS will aid in transforming manufacturing to become more intuitive and automated.In turn,automated manufacturing will pave the way for the decentralization of manufacturing.Layering blockchain technologies on top of CPPS will ensure the reliability and security of data sharing and integration across decentralized systems.Each of these claims is supported by relevant case studies recently published in the literature and from the industry;a brief on existing challenges and the way forward is also provided.展开更多
This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural develop...This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural development. Nowadays the Atlantic Forest is considered the most threatenet biome, because of exploitation of their biological resources and unsuitable agricultural purposes. Banana cultivation is one of biggest commercial productions in atlantic south portion of forest, showing two different cropping systems: one using conventional management tehniques and other antagonistic, ecological based. The ecological system is compatible with the conservation of sustainable use of forests. The article presents a comparative analysis-diagnosis of major production and cultivation systems of banana, using the production systems approach, with evaluation of economic and technical indicators. The database is composed by 17 interviews conducted under field conditions in 2007. As a result, the technical and economic functioning of ecological systems demonstrate achieve economic efficiency, in general, higher than conventional systems. Furthermore, some key characteristics of ecological based systems focus on food production and income generation for farmers without harming areas of the Atlantic Forest, being in equilibrium with tropical dynamic and being an important instrument for the restoration of degraded ecosystems and for local development.展开更多
Worldwide,there are many options to ensure domestic hot water(DHW)provision in dwellings.This study aimed to depict the distribution of energy sources and DHW production systems in the Calabria region.The research was...Worldwide,there are many options to ensure domestic hot water(DHW)provision in dwellings.This study aimed to depict the distribution of energy sources and DHW production systems in the Calabria region.The research was focused on understanding which variables,among contextual variables and building characteristics,may influence the adoption of a particular energy source or production system.Descriptive statistics and chi-square test of independence have been developed.Significant relationships were found between the climatic zone and the energy source used as well as between the climatic zone and the production system installed in both households with a separated and a combined DHW production system.Furthermore,the population of the municipality and the dwelling type resulted to be significant variables for the preference of an energy source or the diffusion of a combined production system.展开更多
Vegetable production systems involve high rates of chemical and organic fertilizer applications,leading to significant P accumulation in vegetable soils,as well as a decrease in P use efficiency(PUE),which is one of t...Vegetable production systems involve high rates of chemical and organic fertilizer applications,leading to significant P accumulation in vegetable soils,as well as a decrease in P use efficiency(PUE),which is one of the key limiting factors in vegetable production.This review introduces the vegetable production systems in China and their fertilization status,and analyzes probable causes of overfertilization of vegetable fields.Poorly developed root systems and high P demand have led to the need to maintain much higher available P concentrations in the root zone for regular growth of vegetables,which might necessitate higher phosphate fertilizer input than the plants require.Research on strategies to improve vegetable PUE and the mechanisms of these strategies are summarized in this review.Increasing the P uptake by vegetables by supplying P during the critical growth stage and effectively utilizing the accumulated P by optimizing the C:P ratio in soils can substantially increase PUE.These advances will provide a basis for improving PUE and optimizing phosphate fertilizer applications in vegetable production through regulatory measures.In addition,some policies are recommended that could ensure the safety of vegetables and improve product quality.This review also aims to improve understanding of P cycling in vegetable fields and assist in the development of best practices to manage P reserves globally.展开更多
Automation of production in the nurseries of flower producing companies using barcode scanners have been attempted but with little success.Stationary laser barcode scanners which have been used for automation have fai...Automation of production in the nurseries of flower producing companies using barcode scanners have been attempted but with little success.Stationary laser barcode scanners which have been used for automation have failed due to the close proximity between the barcode and the scanner,and factors such as speed,angle of inclination of the barcode,damage to the barcode and dirt on the barcode.Furthermore,laser barcode scanners are still being used manually in the nurseries making work laborious and time consuming,which leading to reduced productivity.Therefore,an automated image-based barcode detection system to help solve the aforementioned problems was proposed.Experiments were conducted under different situations with clean and artificially soiled Code 128 barcodes in both the laboratory and under real production conditions in a flower producing company.The images were analyzed with a specific algorithm developed with the software tool Halcon.Overall the results from the company showed that the image-based system has a future prospect for automation in the nursery.展开更多
Designing and developing distributed cyber-physical production systems(CPPS)is a time-consuming,complex,and error-prone process.These systems are typically heterogeneous,i.e.,they consist of multiple components implem...Designing and developing distributed cyber-physical production systems(CPPS)is a time-consuming,complex,and error-prone process.These systems are typically heterogeneous,i.e.,they consist of multiple components implemented with different languages and development tools.One of the main problems nowadays in CPPS implementation is enabling security mechanisms by design while reducing the complexity and increasing the system’s maintainability.Adopting the IEC 61499 standard is an excellent approach to tackle these challenges by enabling the design,deployment,and management of CPPS in a model-based engineering methodology.We propose a method for CPPS design based on the IEC 61499 standard.The method allows designers to embed a bio-inspired anomaly-based host intrusion detection system(A-HIDS)in Edge devices.This A-HIDS is based on the incremental Dendritic Cell Algorithm(iDCA)and can analyze OPC UA network data exchanged between the Edge devices and detect attacks that target the CPPS’Edge layer.This study’s findings have practical implications on the industrial security community by making novel contributions to the intrusion detection problem in CPPS considering immune-inspired solutions,and cost-effective security by design system implementation.According to the experimental data,the proposed solution can dramatically reduce design and code complexity while improving application maintainability and successfully detecting network attacks without negatively impacting the performance of the CPPS Edge devices.展开更多
SARP Workshop on risk analysis of agroecological zonation and optimization of crop rotation was held at CNRRI’s research center on 24—27 Oct, 1995. Experts from Philippines, India, China, and IRRI were present in th...SARP Workshop on risk analysis of agroecological zonation and optimization of crop rotation was held at CNRRI’s research center on 24—27 Oct, 1995. Experts from Philippines, India, China, and IRRI were present in the workshop. Participants exchanged the research results on the field of land use, soil erosion. optimization of rice—wheat, rice—peanut, rice—corn cropping system in the different environments, risk analysis of rice based cropping system, nitrogen balance in rice based cropping system with system approach, demonstrated models used in their studies, and discussed the ongoing cooperative research.展开更多
Though there are many documented reasons that make farmers to adopt organic farming system, economic benefits present a major motivation. The study was conducted to evaluate the impact of organic production system on ...Though there are many documented reasons that make farmers to adopt organic farming system, economic benefits present a major motivation. The study was conducted to evaluate the impact of organic production system on profitability of smallholder vegetable production systems in the two counties so as to appraise its contribution to improvement of rural livelihoods. The study collected data on costs and returns for a sample of 208 smallholder vegetable farmers who were composed of 78 organic and 130 conventional farmers. Impact of organic production system was evaluated using propensity score matching technique. Organic vegetable production system was found to have a positive significant impact of increasing farm gross margin by US$0.58 representing 89.5% among smallholder producers in Kiambu and Kajiado Counties of Kenya. The study recommended promotion of organic production system as a tool that can be used to improve livelihoods especially in the rural areas.展开更多
As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many ...As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many approaches have been suggested for different applications. The goal of this paper is to review these approaches regarding their suitability for the domain of production automation in order to identify current trends and research gaps. The different approaches are classified and clustered according to their main focus which is either testing and test case generation from some form of model automatons, test case generation from models used within the development process of production automation systems, test case generation from fault models or test case selection and regression testing.展开更多
This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and commu...This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.展开更多
In lhis paper, we study the variable structure control of indefinite-dimensionalcontrol systems with the functional analysis method. The reaching conditions, stabilityconditions and the approximating conditions of sli...In lhis paper, we study the variable structure control of indefinite-dimensionalcontrol systems with the functional analysis method. The reaching conditions, stabilityconditions and the approximating conditions of sliding mode, as well as the generalform of the variable structure control law are given. and the elementary frame of thevariable structure control of indefinite-dimensional systems is built.展开更多
Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)...Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.展开更多
Second language acquisition can not be understood without addressing the interaction between language and cognition. Cognitive theory can extend to describe learning strategies as complex cognitive skills. Theoretical...Second language acquisition can not be understood without addressing the interaction between language and cognition. Cognitive theory can extend to describe learning strategies as complex cognitive skills. Theoretical developments in Anderson’s production systems cover a broader range of behavior than other theories, including comprehension and production of oral and written texts as well as comprehension, problem solving, and verbal learning.Thus Anderson’s cognitive theory can be served as a rationale for learning strategy studies in second language acquisition.展开更多
This paper presents a modeling and control of molten metal's pressure in pressing process using an innovative iron casting developed by our group. In this method, molten metal is directly poured into a lower mold, an...This paper presents a modeling and control of molten metal's pressure in pressing process using an innovative iron casting developed by our group. In this method, molten metal is directly poured into a lower mold, and then pressed to fill cavity by an upper mold being lowered down. For complex liquid flow during pressing, the liquid's pressure changing inside vertical path with various contraction and expansion geometries is newly modeled via the unstationary Bernoulli equation. The mathematical model is derived for a control design of pressing. To conduct the pressing velocity design algorithm, an unknown parameter of proposed model considering viscous flow is identified by using CFD (Computational Fluid Dynamics) with heat flow calculation. Control performance using a multi-switching velocity pattern is confirmed as an effective control design using the pressure model, because the pressure fluctuation has discontinuous variation points. Substituting detailed information for mold shape, poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the design algorithm based on the construction of an inverse system comprised of the sequential switching from higher to lower speed. Consequently, the effectiveness of the pressing control with reasonable pressure suppression has been demonstrated through CFD.展开更多
This article brings a discussion about using the Cost Deployment methodology for technological innovation in the World Class Manufacturing (WCM) systems at Fiat Group Automobiles Production System (FAPS). It aims to s...This article brings a discussion about using the Cost Deployment methodology for technological innovation in the World Class Manufacturing (WCM) systems at Fiat Group Automobiles Production System (FAPS). It aims to show how this tool acts in the technical pillars of the WCM, and its proper use as an alternative to innovate in production processes, achieving a drastic reduction in wastes and cost optimization during specific activities in production systems. The Cost Deployment builds a distinctive transversal method of WCM which helps to promote and provide extremely effectiveness in the activation of more specific methods that have been tried successfully in the Japanese manufacturing improvements. It also allows to link the operational performances, usually measured with indicators such as efficiency, providing number of defects, hours of desaturation. The used methodology was based on a literature review about the proposed topic. It ends up finding that the Cost Deployment tool is one of the most sophisticated technological innovations existing for the production systems of the World Class Manufacturing.展开更多
Changes in requirements may result in the increasing of product development project cost and lead time, therefore, it is important to understand how require- ment changes propagate in the design of complex product sys...Changes in requirements may result in the increasing of product development project cost and lead time, therefore, it is important to understand how require- ment changes propagate in the design of complex product systems and be able to select best options to guide design. Currently, a most approach for design change is lack of take the multi-disciplinary coupling relationships and the number of parameters into account integrally. A new design change model is presented to systematically analyze and search change propagation paths. Firstly, a PDS-Be- havior-Structure-based design change model is established to describe requirement changes causing the design change propagation in behavior and structure domains. Secondly, a multi-disciplinary oriented behavior matrix is utilized to support change propagation analysis of complex product systems, and the interaction relationships of the matrix elements are used to obtain an initial set of change paths. Finally, a rough set-based propagation space reducing tool is developed to assist in narrowing change propagation paths by computing the importance of the design change parameters. The proposed new design change model and its associated tools have been demonstrated by the scheduling change propagation paths of high speed train's bogie to show its feasibility and effectiveness. This model is not only supportive to response quickly to diversified market requirements, but also helpful to satisfy customer require- ments and reduce product development lead time. The proposed new design change model can be applied in a wide range of engineering systems design with improved efficiency.展开更多
This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the com...This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the companies in such aspects as improving design productivity, better control over projects and so on. With the maturing of web technologies, the advantages of WPDM system are obvious. We will show these advantages in detail in Part 3. WPDM system is built on three-tier application model to provide security and flexibility, they are back-end, middle layer and front-end. The basic designs in each layer will be briefly introduced in Part 4. In the future, WPDM will be extended to integrate with other applications to provide a complete web-based engineering environment.展开更多
Let X={X_(p)}p∈Pbe a product system over a lattice ordered group(G,P)with coefficients in a C*-algebra A.In this paper,we study the reduced crossed product of the gauge coactionδof G on the Cuntz-Pimsner algebra NO_...Let X={X_(p)}p∈Pbe a product system over a lattice ordered group(G,P)with coefficients in a C*-algebra A.In this paper,we study the reduced crossed product of the gauge coactionδof G on the Cuntz-Pimsner algebra NO_(X)^(r).When X is a product system of Morita equivalence bimodules,we show that the reduced crossed product of the gauge coaction is Morita equivalent to the C*-algebra A.展开更多
This paper develops twin models towards integrated production inventory planning for manufacturer–retailer ecosystem in a sustainable supply chain setup.Decision-making models are developed in fuzzy environment and u...This paper develops twin models towards integrated production inventory planning for manufacturer–retailer ecosystem in a sustainable supply chain setup.Decision-making models are developed in fuzzy environment and under purview of carbon taxation system.Novel conception of Fermatean fuzzy numbers is introduced for handling parameters imprecision.The first model addresses planning problem without considering green investments,whereas the second one additionally identifies optimal green investments for each player of ecosystem.Models are formulated as nonlinear optimization problems with objective of maximizing profit.Comparison of results from both models enables decision-makers to figure out the profitability of green investment option.Numerical instance with data from the existing literature is solved using Mathematica 12.1.Computational results for studied case report profitability of green investments for supply chain partners and significant reduction in carbon emissions as well.Variation analysis demonstrates stability of the proposed model.Developed models equip small-scale retailer-manufacture tie-ups prevalent in developing economies for discussed decisions.展开更多
基金supported by the National Natural Science Foundation of China(42207529)the China Postdoctoral Science Foundation(2022M721289).
文摘Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied extensively.Labor migration in rural China has taken new forms in recent years.There has been a discernible trend wherein adult children have started migrating to cities while their elderly parents return to villages to re-engage in on-farm work.The phenomenon has notably shaped the intergenerational division of labor(IDL)within households.However,it remains to be seen how farmers adjust their rice production systems in response to the IDL.The age of 60 years for employment injury insurance is the eligibility threshold for off-farm employment and is used to obtain a source of exogenous variation in the IDL.Based on a representative household survey of 1,752 rice farmers in the Hubei Province of Central China,our fuzzy regression discontinuity analysis reveals that farmers in IDL households are more likely to adopt ratoon rice(RR)than single cropping rice(SR)or double cropping rice(DR).The effect of the IDL varies under different levels of operational scales and specialized agricultural service availability.Further analysis suggests that farmers’arrangements are associated with two potential mechanisms of downward intergenerational transfer.Monetary transfer for urban housing purchases increases RR in IDL households,and time transfer for intergenerational childcare significantly promotes SR in IDL households.This study enhances the understanding of the relationship between rural labor migration and rice production in China,providing a reference for adjusting rice production systems to ensure food security.
文摘With the concepts of Industry 4.0 and smart manufacturing gaining popularity,there is a growing notion that conventional manufacturing will witness a transition toward a new paradigm,targeting innovation,automation,better response to customer needs,and intelligent systems.Within this context,this review focuses on the concept of cyber–physical production system(CPPS)and presents a holistic perspective on the role of the CPPS in three key and essential drivers of this transformation:data-driven manufacturing,decentralized manufacturing,and integrated blockchains for data security.The paper aims to connect these three aspects of smart manufacturing and proposes that through the application of data-driven modeling,CPPS will aid in transforming manufacturing to become more intuitive and automated.In turn,automated manufacturing will pave the way for the decentralization of manufacturing.Layering blockchain technologies on top of CPPS will ensure the reliability and security of data sharing and integration across decentralized systems.Each of these claims is supported by relevant case studies recently published in the literature and from the industry;a brief on existing challenges and the way forward is also provided.
文摘This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural development. Nowadays the Atlantic Forest is considered the most threatenet biome, because of exploitation of their biological resources and unsuitable agricultural purposes. Banana cultivation is one of biggest commercial productions in atlantic south portion of forest, showing two different cropping systems: one using conventional management tehniques and other antagonistic, ecological based. The ecological system is compatible with the conservation of sustainable use of forests. The article presents a comparative analysis-diagnosis of major production and cultivation systems of banana, using the production systems approach, with evaluation of economic and technical indicators. The database is composed by 17 interviews conducted under field conditions in 2007. As a result, the technical and economic functioning of ecological systems demonstrate achieve economic efficiency, in general, higher than conventional systems. Furthermore, some key characteristics of ecological based systems focus on food production and income generation for farmers without harming areas of the Atlantic Forest, being in equilibrium with tropical dynamic and being an important instrument for the restoration of degraded ecosystems and for local development.
文摘Worldwide,there are many options to ensure domestic hot water(DHW)provision in dwellings.This study aimed to depict the distribution of energy sources and DHW production systems in the Calabria region.The research was focused on understanding which variables,among contextual variables and building characteristics,may influence the adoption of a particular energy source or production system.Descriptive statistics and chi-square test of independence have been developed.Significant relationships were found between the climatic zone and the energy source used as well as between the climatic zone and the production system installed in both households with a separated and a combined DHW production system.Furthermore,the population of the municipality and the dwelling type resulted to be significant variables for the preference of an energy source or the diffusion of a combined production system.
基金supported by the National Key Research and Development Program of China (2017YFD0200200/ 2017YFD0200208)the National Natural Science Foundation of China (31872957)the Knowledge Innovation Program of the Chinese Academy of Sciences (ISSASIP1608)
文摘Vegetable production systems involve high rates of chemical and organic fertilizer applications,leading to significant P accumulation in vegetable soils,as well as a decrease in P use efficiency(PUE),which is one of the key limiting factors in vegetable production.This review introduces the vegetable production systems in China and their fertilization status,and analyzes probable causes of overfertilization of vegetable fields.Poorly developed root systems and high P demand have led to the need to maintain much higher available P concentrations in the root zone for regular growth of vegetables,which might necessitate higher phosphate fertilizer input than the plants require.Research on strategies to improve vegetable PUE and the mechanisms of these strategies are summarized in this review.Increasing the P uptake by vegetables by supplying P during the critical growth stage and effectively utilizing the accumulated P by optimizing the C:P ratio in soils can substantially increase PUE.These advances will provide a basis for improving PUE and optimizing phosphate fertilizer applications in vegetable production through regulatory measures.In addition,some policies are recommended that could ensure the safety of vegetables and improve product quality.This review also aims to improve understanding of P cycling in vegetable fields and assist in the development of best practices to manage P reserves globally.
基金This project was part of the WeGa-Network(www.wega-online.org)funded by the German Federal Ministry of Education and Research.
文摘Automation of production in the nurseries of flower producing companies using barcode scanners have been attempted but with little success.Stationary laser barcode scanners which have been used for automation have failed due to the close proximity between the barcode and the scanner,and factors such as speed,angle of inclination of the barcode,damage to the barcode and dirt on the barcode.Furthermore,laser barcode scanners are still being used manually in the nurseries making work laborious and time consuming,which leading to reduced productivity.Therefore,an automated image-based barcode detection system to help solve the aforementioned problems was proposed.Experiments were conducted under different situations with clean and artificially soiled Code 128 barcodes in both the laboratory and under real production conditions in a flower producing company.The images were analyzed with a specific algorithm developed with the software tool Halcon.Overall the results from the company showed that the image-based system has a future prospect for automation in the nursery.
文摘Designing and developing distributed cyber-physical production systems(CPPS)is a time-consuming,complex,and error-prone process.These systems are typically heterogeneous,i.e.,they consist of multiple components implemented with different languages and development tools.One of the main problems nowadays in CPPS implementation is enabling security mechanisms by design while reducing the complexity and increasing the system’s maintainability.Adopting the IEC 61499 standard is an excellent approach to tackle these challenges by enabling the design,deployment,and management of CPPS in a model-based engineering methodology.We propose a method for CPPS design based on the IEC 61499 standard.The method allows designers to embed a bio-inspired anomaly-based host intrusion detection system(A-HIDS)in Edge devices.This A-HIDS is based on the incremental Dendritic Cell Algorithm(iDCA)and can analyze OPC UA network data exchanged between the Edge devices and detect attacks that target the CPPS’Edge layer.This study’s findings have practical implications on the industrial security community by making novel contributions to the intrusion detection problem in CPPS considering immune-inspired solutions,and cost-effective security by design system implementation.According to the experimental data,the proposed solution can dramatically reduce design and code complexity while improving application maintainability and successfully detecting network attacks without negatively impacting the performance of the CPPS Edge devices.
文摘SARP Workshop on risk analysis of agroecological zonation and optimization of crop rotation was held at CNRRI’s research center on 24—27 Oct, 1995. Experts from Philippines, India, China, and IRRI were present in the workshop. Participants exchanged the research results on the field of land use, soil erosion. optimization of rice—wheat, rice—peanut, rice—corn cropping system in the different environments, risk analysis of rice based cropping system, nitrogen balance in rice based cropping system with system approach, demonstrated models used in their studies, and discussed the ongoing cooperative research.
文摘Though there are many documented reasons that make farmers to adopt organic farming system, economic benefits present a major motivation. The study was conducted to evaluate the impact of organic production system on profitability of smallholder vegetable production systems in the two counties so as to appraise its contribution to improvement of rural livelihoods. The study collected data on costs and returns for a sample of 208 smallholder vegetable farmers who were composed of 78 organic and 130 conventional farmers. Impact of organic production system was evaluated using propensity score matching technique. Organic vegetable production system was found to have a positive significant impact of increasing farm gross margin by US$0.58 representing 89.5% among smallholder producers in Kiambu and Kajiado Counties of Kenya. The study recommended promotion of organic production system as a tool that can be used to improve livelihoods especially in the rural areas.
文摘As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many approaches have been suggested for different applications. The goal of this paper is to review these approaches regarding their suitability for the domain of production automation in order to identify current trends and research gaps. The different approaches are classified and clustered according to their main focus which is either testing and test case generation from some form of model automatons, test case generation from models used within the development process of production automation systems, test case generation from fault models or test case selection and regression testing.
基金the support of the National Natural Science Foundation of China (Grant No.41501104)the National Key Technology R&D Program of China (Grant Nos.2013BAJ11B02,2013BAJ11B02-03)+1 种基金the Basic and Frontier Research Project of Chongqing Science &Technology Commission (Grant No.cstc2015jcyj A80025)the Science and technology research project of Chongqing Education Committee (Grant No.KJ1500336)
文摘This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.
文摘In lhis paper, we study the variable structure control of indefinite-dimensionalcontrol systems with the functional analysis method. The reaching conditions, stabilityconditions and the approximating conditions of sliding mode, as well as the generalform of the variable structure control law are given. and the elementary frame of thevariable structure control of indefinite-dimensional systems is built.
基金funded by the Deputy of Research Affairs, Lorestan University, Iran (Contract No. 1400-6-02-518-1402)
文摘Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.
文摘Second language acquisition can not be understood without addressing the interaction between language and cognition. Cognitive theory can extend to describe learning strategies as complex cognitive skills. Theoretical developments in Anderson’s production systems cover a broader range of behavior than other theories, including comprehension and production of oral and written texts as well as comprehension, problem solving, and verbal learning.Thus Anderson’s cognitive theory can be served as a rationale for learning strategy studies in second language acquisition.
文摘This paper presents a modeling and control of molten metal's pressure in pressing process using an innovative iron casting developed by our group. In this method, molten metal is directly poured into a lower mold, and then pressed to fill cavity by an upper mold being lowered down. For complex liquid flow during pressing, the liquid's pressure changing inside vertical path with various contraction and expansion geometries is newly modeled via the unstationary Bernoulli equation. The mathematical model is derived for a control design of pressing. To conduct the pressing velocity design algorithm, an unknown parameter of proposed model considering viscous flow is identified by using CFD (Computational Fluid Dynamics) with heat flow calculation. Control performance using a multi-switching velocity pattern is confirmed as an effective control design using the pressure model, because the pressure fluctuation has discontinuous variation points. Substituting detailed information for mold shape, poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the design algorithm based on the construction of an inverse system comprised of the sequential switching from higher to lower speed. Consequently, the effectiveness of the pressing control with reasonable pressure suppression has been demonstrated through CFD.
文摘This article brings a discussion about using the Cost Deployment methodology for technological innovation in the World Class Manufacturing (WCM) systems at Fiat Group Automobiles Production System (FAPS). It aims to show how this tool acts in the technical pillars of the WCM, and its proper use as an alternative to innovate in production processes, achieving a drastic reduction in wastes and cost optimization during specific activities in production systems. The Cost Deployment builds a distinctive transversal method of WCM which helps to promote and provide extremely effectiveness in the activation of more specific methods that have been tried successfully in the Japanese manufacturing improvements. It also allows to link the operational performances, usually measured with indicators such as efficiency, providing number of defects, hours of desaturation. The used methodology was based on a literature review about the proposed topic. It ends up finding that the Cost Deployment tool is one of the most sophisticated technological innovations existing for the production systems of the World Class Manufacturing.
基金Supported by National Natural Science Foundation of China(Grant Nos.51305367,51575461)Doctoral Student Innovation Funds for Hai-Zhu Zhang from Southwest Jiaotong University,China
文摘Changes in requirements may result in the increasing of product development project cost and lead time, therefore, it is important to understand how require- ment changes propagate in the design of complex product systems and be able to select best options to guide design. Currently, a most approach for design change is lack of take the multi-disciplinary coupling relationships and the number of parameters into account integrally. A new design change model is presented to systematically analyze and search change propagation paths. Firstly, a PDS-Be- havior-Structure-based design change model is established to describe requirement changes causing the design change propagation in behavior and structure domains. Secondly, a multi-disciplinary oriented behavior matrix is utilized to support change propagation analysis of complex product systems, and the interaction relationships of the matrix elements are used to obtain an initial set of change paths. Finally, a rough set-based propagation space reducing tool is developed to assist in narrowing change propagation paths by computing the importance of the design change parameters. The proposed new design change model and its associated tools have been demonstrated by the scheduling change propagation paths of high speed train's bogie to show its feasibility and effectiveness. This model is not only supportive to response quickly to diversified market requirements, but also helpful to satisfy customer require- ments and reduce product development lead time. The proposed new design change model can be applied in a wide range of engineering systems design with improved efficiency.
文摘This paper is concerned with the development of product data management (PDM) systems--WPDM systems based on web technologies. As a tool to integrate information, traditional PDM system has many benefits for the companies in such aspects as improving design productivity, better control over projects and so on. With the maturing of web technologies, the advantages of WPDM system are obvious. We will show these advantages in detail in Part 3. WPDM system is built on three-tier application model to provide security and flexibility, they are back-end, middle layer and front-end. The basic designs in each layer will be briefly introduced in Part 4. In the future, WPDM will be extended to integrate with other applications to provide a complete web-based engineering environment.
基金Wang was supported in part by NSF of China(Grant Nos.11871303,11971463,11671133)NSF of Shandong Province(Grant No.ZR2019MA039)Yuan was supported in part by NSF of China(Grant Nos.11871303,11871127,11971463)。
文摘Let X={X_(p)}p∈Pbe a product system over a lattice ordered group(G,P)with coefficients in a C*-algebra A.In this paper,we study the reduced crossed product of the gauge coactionδof G on the Cuntz-Pimsner algebra NO_(X)^(r).When X is a product system of Morita equivalence bimodules,we show that the reduced crossed product of the gauge coaction is Morita equivalent to the C*-algebra A.
文摘This paper develops twin models towards integrated production inventory planning for manufacturer–retailer ecosystem in a sustainable supply chain setup.Decision-making models are developed in fuzzy environment and under purview of carbon taxation system.Novel conception of Fermatean fuzzy numbers is introduced for handling parameters imprecision.The first model addresses planning problem without considering green investments,whereas the second one additionally identifies optimal green investments for each player of ecosystem.Models are formulated as nonlinear optimization problems with objective of maximizing profit.Comparison of results from both models enables decision-makers to figure out the profitability of green investment option.Numerical instance with data from the existing literature is solved using Mathematica 12.1.Computational results for studied case report profitability of green investments for supply chain partners and significant reduction in carbon emissions as well.Variation analysis demonstrates stability of the proposed model.Developed models equip small-scale retailer-manufacture tie-ups prevalent in developing economies for discussed decisions.