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Requirements ranking based on crowd-sourcing high-end product USs
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作者 MA Yufeng DOU Yajie +2 位作者 XU Xiangqian JIA Qingyang TAN Yuejin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期94-104,共11页
Based on the characteristics of high-end products,crowd-sourcing user stories can be seen as an effective means of gathering requirements,involving a large user base and generating a substantial amount of unstructured... Based on the characteristics of high-end products,crowd-sourcing user stories can be seen as an effective means of gathering requirements,involving a large user base and generating a substantial amount of unstructured feedback.The key challenge lies in transforming abstract user needs into specific ones,requiring integration and analysis.Therefore,we propose a topic mining-based approach to categorize,summarize,and rank product requirements from user stories.Specifically,after determining the number of story categories based on py LDAvis,we initially classify“I want to”phrases within user stories.Subsequently,classic topic models are applied to each category to generate their names,defining each post-classification user story category as a requirement.Furthermore,a weighted ranking function is devised to calculate the importance of each requirement.Finally,we validate the effectiveness and feasibility of the proposed method using 2966 crowd-sourced user stories related to smart home systems. 展开更多
关键词 high-end product complex system crowd-sourcing user stories topic mining requirements ranking
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Autoantibodies against beta cells to predict early insulin requirements in pediatric patients with clinically diagnosed type 2 diabetes
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作者 Jorge M Molina Patricia G Medina +4 位作者 Rita A Gomez Julia R Herrera Nancy L Martínez Brenda Hernández Yesenia García 《World Journal of Diabetes》 SCIE 2024年第8期1717-1725,共9页
BACKGROUND Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus(T2DM),that is,patients who have insulin resistance,obesity,and other cardiovascular ris... BACKGROUND Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus(T2DM),that is,patients who have insulin resistance,obesity,and other cardiovascular risk factors,suggesting that the presence of glutamic acid decarboxylase(anti-GAD65),islet antigen 2(anti-IA2),and zinc transporter 8(anti-Zn8T)antibodies could have deleterious effects on beta cell function,causing failure and earlier requirement for insulin treatment.AIM To evaluate anti-GAD65,anti-IA2 and anti-Zn8T as predictors of early insulin requirement in adolescents with a clinical diagnosis of T2DM.METHODS This was a case–control study in patients with clinically diagnosed with T2DM(68 cases and 64 controls with and without early insulin dependence respectively),male and female,aged 12–18 years.Somatometry,blood pressure,glucose,insulin,C-peptide,glycated hemoglobin A1c,and lipid profiles were assessed.ELISA was used to measure anti-GAD65,anti-IA2,and anti-Zn8T antibodies.Descriptive statistics,Pearson'sχ2 test,Student's t test,and logistic regression was performed.P<0.05 was considered statistically significant.RESULTS There were 132 patients(53.8%female),with a mean age was 15.9±1.3 years,and there was a disease evolution time of 4.49±0.88 years.The presence of anti-GAD65,anti-IA2,and anti-Zn8T positivity was found in 29.5%,18.2%,and 15.9%,respectively.Dividing the groups by early or no insulin dependence showed that the group with insulin had a higher frequency of antibody positivity:anti-GAD65 odds ratio(OR):2.42(1.112–5.303,P=0.026);anti-IA2:OR:1.55(0.859–2.818,P=0.105);and anti-Zn8T:OR:7.32(2.039–26.279,P=0.002).CONCLUSION Anti-GAD65 positivity was high in our study.Anti-GAD65 and anti-Zn8T positivity showed a significantly depleted beta cell reserve phenotype,leading to an increased risk of early insulin dependence. 展开更多
关键词 DIABETES OBESITY Adolescents AUTOIMMUNITY Beta cell Insulin requirements
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How to implement a knowledge graph completeness assessment with the guidance of user requirements
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作者 ZHANG Ying XIAO Gang 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第3期679-688,共10页
In the context of big data, many large-scale knowledge graphs have emerged to effectively organize the explosive growth of web data on the Internet. To select suitable knowledge graphs for use from many knowledge grap... In the context of big data, many large-scale knowledge graphs have emerged to effectively organize the explosive growth of web data on the Internet. To select suitable knowledge graphs for use from many knowledge graphs, quality assessment is particularly important. As an important thing of quality assessment, completeness assessment generally refers to the ratio of the current data volume to the total data volume.When evaluating the completeness of a knowledge graph, it is often necessary to refine the completeness dimension by setting different completeness metrics to produce more complete and understandable evaluation results for the knowledge graph.However, lack of awareness of requirements is the most problematic quality issue. In the actual evaluation process, the existing completeness metrics need to consider the actual application. Therefore, to accurately recommend suitable knowledge graphs to many users, it is particularly important to develop relevant measurement metrics and formulate measurement schemes for completeness. In this paper, we will first clarify the concept of completeness, establish each metric of completeness, and finally design a measurement proposal for the completeness of knowledge graphs. 展开更多
关键词 knowledge graph completeness assessment relative completeness user requirement quality management
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Research Progress on Nutritional Requirements of Carp
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作者 Yina LU 《Asian Agricultural Research》 2024年第1期37-39,43,共4页
Carp is a temperate freshwater fish native to Asia,distributed in all regions of the world except Australia and South America.With the improvement of comprehensive and healthy breeding technology of carp,the unit yiel... Carp is a temperate freshwater fish native to Asia,distributed in all regions of the world except Australia and South America.With the improvement of comprehensive and healthy breeding technology of carp,the unit yield has been greatly increased mainly due to the exten-sive use of compound feed.In this study,the nutritional requirements of carp were summarized from the aspects of protein,amino acids,fat,carbohydrate,calcium and phosphorus,vitamins and taurine.This study provides a certain theoretical reference for scientific formula of carp feed. 展开更多
关键词 CARP Nutritional requirements Foreground
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Security and Privacy in Solar Insecticidal Lamps Internet of Things:Requirements and Challenges
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作者 Qingsong Zhao Lei Shu +3 位作者 Kailiang Li Mohamed Amine Ferrag Ximeng Liu Yanbin Li 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第1期58-73,共16页
Solar insecticidal lamps(SIL) can effectively control pests and reduce the use of pesticides. Combining SIL and Internet of Things(IoT) has formed a new type of agricultural IoT,known as SIL-IoT, which can improve the... Solar insecticidal lamps(SIL) can effectively control pests and reduce the use of pesticides. Combining SIL and Internet of Things(IoT) has formed a new type of agricultural IoT,known as SIL-IoT, which can improve the effectiveness of migratory phototropic pest control. However, since the SIL is connected to the Internet, it is vulnerable to various security issues.These issues can lead to serious consequences, such as tampering with the parameters of SIL, illegally starting and stopping SIL,etc. In this paper, we describe the overall security requirements of SIL-IoT and present an extensive survey of security and privacy solutions for SIL-IoT. We investigate the background and logical architecture of SIL-IoT, discuss SIL-IoT security scenarios, and analyze potential attacks. Starting from the security requirements of SIL-IoT we divide them into six categories, namely privacy, authentication, confidentiality, access control, availability,and integrity. Next, we describe the SIL-IoT privacy and security solutions, as well as the blockchain-based solutions. Based on the current survey, we finally discuss the challenges and future research directions of SIL-IoT. 展开更多
关键词 CHALLENGES Internet of Things(IoT) privacy and security security requirements solar insecticidal lamps(SIL)
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Operational requirements analysis method based on question answering of WEKG
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作者 ZHANG Zhiwei DOU Yajie +3 位作者 XU Xiangqian MA Yufeng JIANG Jiang TAN Yuejin 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期386-395,共10页
The weapon and equipment operational requirement analysis(WEORA) is a necessary condition to win a future war,among which the acquisition of knowledge about weapons and equipment is a great challenge. The main challen... The weapon and equipment operational requirement analysis(WEORA) is a necessary condition to win a future war,among which the acquisition of knowledge about weapons and equipment is a great challenge. The main challenge is that the existing weapons and equipment data fails to carry out structured knowledge representation, and knowledge navigation based on natural language cannot efficiently support the WEORA. To solve above problem, this research proposes a method based on question answering(QA) of weapons and equipment knowledge graph(WEKG) to construct and navigate the knowledge related to weapons and equipment in the WEORA. This method firstly constructs the WEKG, and builds a neutral network-based QA system over the WEKG by means of semantic parsing for knowledge navigation. Finally, the method is evaluated and a chatbot on the QA system is developed for the WEORA. Our proposed method has good performance in the accuracy and efficiency of searching target knowledge, and can well assist the WEORA. 展开更多
关键词 operational requirement analysis weapons and equipment knowledge graph(WEKG) question answering(QA) neutral network
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The Customer Requirements Analysis Method of Engineering Products Based on Multiple Preference Information
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作者 Guo Mao 《Proceedings of Business and Economic Studies》 2024年第1期204-209,共6页
To effectively evaluate the fuzziness of the market environment in product planning,a customer requirements analysis method based on multiple preference information is proposed.Firstly,decision-makers use a preferred ... To effectively evaluate the fuzziness of the market environment in product planning,a customer requirements analysis method based on multiple preference information is proposed.Firstly,decision-makers use a preferred information form to evaluate the importance of each customer requirement.Secondly,a transfer function is employed to unify various forms of preference information into a fuzzy complementary judgment matrix.The ranking vector is then calculated using row and normalization methods,and the initial importance of customer requirements is obtained by aggregating the weights of decision members.Finally,the correction coefficients of initial importance and each demand are synthesized,and the importance of customer requirements is determined through normalization.The development example of the PE jaw crusher demonstrates the effectiveness and feasibility of the proposed method. 展开更多
关键词 Product planning Customer requirements Importance ratings Multi-format information
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On the Assessment of Generative AI in Requirements Analysis and Modeling Tasks with UML:An Exploratory Study
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作者 Chong Wang Peng Liang +2 位作者 Xiaojian Li Jian Wang Zhong Luo 《计算机教育》 2023年第12期2-10,共9页
Generative AI is rapidly employed by software developers to generate code or other software artifacts.However,the analysis and assessment of generative AI with respect to requirements analysis and modeling tasks,espec... Generative AI is rapidly employed by software developers to generate code or other software artifacts.However,the analysis and assessment of generative AI with respect to requirements analysis and modeling tasks,especially with UML,has received little attention.This paper investigates the capabilities of generative AI to aid in the creation of three types of UML models:UML use case models,class diagrams,and sequence diagrams.For this purpose,we designed an AI-aided UML modeling task in our course on software requirements modeling.50 undergraduates who majored in Software Engineering at Wuhan University completed the modeling task and the corresponding online survey.Our findings show that generative AI can help create these three types of UML models,but its performance is limited to identifying essential modeling elements of these UML models. 展开更多
关键词 AI-aided education UML modeling Generative AI requirements engineering
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IoT for Streetlighting-Requirements for Modelling of Management Services-Part I
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作者 Mila Ilieva-Obretenova Radi Pipev 《Management Studies》 2023年第5期245-252,共8页
Energy conservation is the effort to reduce the overconsumption of energy by the usage of less energy services.Energy conservation could be user oriented or industry sector oriented.One of these sectors is the streetl... Energy conservation is the effort to reduce the overconsumption of energy by the usage of less energy services.Energy conservation could be user oriented or industry sector oriented.One of these sectors is the streetlighting-major energy consumer in the town-forming nearly 30%of each country’s consumption.Intelligent designed management of streetlighting not only reduces the energy consumption of the town,but also increases the public safety and the wellbeing.The article focuses the management of IoT for streetlighting in smart city.This is the first stage of project“Service management for IoT in streetlighting”.While the basic management principles are efficiency and fairness,the requirements of all actors must be defined.On the base of requirements,the authors synthesize the management functions with selected granularity.The chosen methodology is unified modelling language(UML):use case diagrams.The models are intended to business developers,university professors,and students. 展开更多
关键词 streetlighting IOT requirements management system UML
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An Approach towards Goal-Oriented Requirements Ontology: Consistency and Completeness Based Requirements Analysis
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作者 Mohammad Mustafa Taye Said Ghoul 《Journal of Software Engineering and Applications》 2023年第2期31-49,共19页
The paper presents a new approach to managing software requirement elicitation techniques with a high level of analyses based on domain ontology techniques, where we established a mapping between user scenario, struct... The paper presents a new approach to managing software requirement elicitation techniques with a high level of analyses based on domain ontology techniques, where we established a mapping between user scenario, structured requirement, and domain ontology techniques to improve many attributes such as requirement consistency, completeness and eliminating duplicate requirements to reduce risk of overrun time and budgets. One of the main targets of requirement engineering is to develop a requirement document with high quality. So, we proposed a user interface to collect all vital information about the project directly from the regular user and requirement engineering;After that, the proposal will generate an ontology based on semantic relations and rules. Requirements Engineering tries to keep requirements throughout a project’s life cycle consistent necessities clear, and up to date. This prototype allows mapping requirement scenarios into ontology elements for semantically interrupted. The general points of our prototype are to guarantee the identification requirements and improved nature of the Software Requirements Specification (SRS) by solving incomplete and conflicting information in the requirements specification. 展开更多
关键词 requirements Engineering requirements Elicitation Domain Ontology ONTOLOGY
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Estimating shear strength of high-level pillars supported with cemented backfilling using the HoekeBrown strength criterion
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作者 Kaizong Xia Congxin Chen +3 位作者 Xiumin Liu Yue Wang Xuanting Liu Jiahao Yuan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期454-469,共16页
Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining method.At the design stage,it is therefore important to have a reasonable method for determining the s... Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining method.At the design stage,it is therefore important to have a reasonable method for determining the shear strength of the high-level pillars(i.e.cohesion and internal friction angle)when they are supported by cemented backfilling.In this study,a formula was derived for the upper limit of the confining pressure σ3max on a high-level pillar supported by cemented backfilling in a deep metal mine.A new method of estimating the shear strength of such pillars was then proposed based on the Hoek eBrown failure criterion.Our analysis indicates that the horizontal stress σhh acting on the cemented backfill pillar can be simplified by expressing it as a constant value.A reasonable and effective value for σ3max can then be determined.The value of s3max predicted using the proposed method is generally less than 3 MPa.Within this range,the shear strength of the high-level pillar is accurately calculated using the equivalent MohreCoulomb theory.The proposed method can effectively avoid the calculation of inaccurate shear strength values for the high-level pillars when the original HoekeBrown criterion is used in the presence of large confining pressures,i.e.the situation in which the cohesion value is too large and the friction angle is too small can effectively be avoided.The proposed method is applied to a deep metal mine in China that is being excavated using the HLSCB method.The shear strength parameters of the high-level pillars obtained using the proposed method were input in the numerical simulations.The numerical results show that the recommended level heights and sizes of the high-level pillars and rooms in the mine are rational. 展开更多
关键词 Deep metal mines high-level pillars HoekeBrown strength criterion Cemented backfilling Confining pressure Shear strength
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Research on the Path of Cultivating High-Level Technical and Skilled Talents in Vocational Undergraduate Colleges and Universities
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作者 Kan Su Seong Pek Lim Linli Yao 《Journal of Contemporary Educational Research》 2024年第7期150-157,共8页
This paper explores strategies to cultivate high-level technical talents in vocational undergraduate colleges by analyzing their development,the essence of such talents,and proposing several key measures.Strategies in... This paper explores strategies to cultivate high-level technical talents in vocational undergraduate colleges by analyzing their development,the essence of such talents,and proposing several key measures.Strategies include optimizing professional settings and curricula,enhancing school-enterprise cooperation and the integration of industry-university-research,improving teaching staff quality and educational standards,and expanding international cooperation.The importance of policy support and funding and establishing robust quality assurance systems is emphasized for effectively cultivating skilled talents in vocational undergraduate colleges. 展开更多
关键词 Vocational undergraduate colleges high-level technical talents Professional setting Innovation and entrepreneurship education
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Professional Requirements for Contemporary Teachers
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作者 丁丽红 《海外英语》 2011年第3X期135-136,共2页
The rapid development of high-tech based information technology marks the era of a knowledge-based economy. This form of economy, characterized by knowledge, has raised new demands for most teachers. To rise to the ch... The rapid development of high-tech based information technology marks the era of a knowledge-based economy. This form of economy, characterized by knowledge, has raised new demands for most teachers. To rise to the challenge, teachers must maintain innovative attitudes and practical abilities that will meet the social requirements. The writer examines the professional requirements for contemporary teachers in this paper. 展开更多
关键词 CONTEMPORARY TEACHERS PROFESSIONAL requirements teachers’ CULTURE
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Dietary requirements of synthesizable amino acids by animals:a paradigm shift in protein nutrition 被引量:23
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作者 Guoyao Wu 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2015年第1期1-12,共12页
Amino acids are building blocks for proteins in all animals. Based on growth or nitrogen balance, amino acids were traditionally classified as nutritionally essential or nonessential for mammals, birds and fish. It wa... Amino acids are building blocks for proteins in all animals. Based on growth or nitrogen balance, amino acids were traditionally classified as nutritionally essential or nonessential for mammals, birds and fish. It was assumed that all the "nutritionally nonessential amino acids (NEAA)" were synthesized sufficiently in the body to meet the needs for maximal growth and optimal health. However, careful analysis of the scientific literature reveals that over the past century there has not been compelling experimental evidence to support this assumption. NEAA (e.g., glutamine, glutamate, proline, glycine and arginine) play important roles in regulating gene expression, cell signaling, antioxidative responses, fertility, neurotransmission, and immunity. Additionally, glutamate, glutamine and aspartate are major metabolic fuels for the small intestine to maintain its digestive function and to protect the integrity of the intestinal mucosa. Thus, diets for animals must contain all NEAA to optimize their survival, growth, development, reproduction, and health. Furthermore, NEAA should be taken into consideration in revising the "ideal protein" concept that is currently used to formulate swine and poultry diets. Adequate provision of all amino acids (including NEAA) in diets enhances the efficiency of animal production. In this regard, amino acids should not be classified as nutritionally essential or nonessential in animal or human nutrition. The new Texas A&M University's optimal ratios of dietary amino acids for swine and chickens are expected to beneficially reduce dietary protein content and improve the efficiency of their nutrient utilization, growth, and production performance. 展开更多
关键词 DIET METABOLISM NUTRITION Protein requirements
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Specifying Requirements of Real-Time System with Rules and Templates 被引量:8
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作者 Wu Guo-qing Xiao Hai-feng +1 位作者 Zheng Pen Ying Shi 《Wuhan University Journal of Natural Sciences》 EI CAS 2000年第3期278-284,共7页
This paper presents a model specifying requirements of real-time systems. Different from existing researches, this model mainly uses rules and templates to represent hierarchical FSMs (Finite State Machine). In this m... This paper presents a model specifying requirements of real-time systems. Different from existing researches, this model mainly uses rules and templates to represent hierarchical FSMs (Finite State Machine). In this model, one rule corresponds to one state transition of FSM and one template corresponds to one FSM. Rules and information with respect to a FSM can be written in a template. So templates include not only state diagrams, but also information that can not be described by FSM, such as performance requirements. The specification using this model consists of a collection of templates and it is easy for users to understand and to review. After introduced the related researches and principles of the model, this paper specifies requirements of a real-time system with this model, and discusses characters of this model in the end. 展开更多
关键词 requirements specification model requirements specification real-time system finite state machine
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Practical starter pig amino acid requirements in relation to immunity,gut health and growth performance 被引量:8
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作者 Bob Goodband Mike Tokach +2 位作者 Steve Dritz Joel DeRouchey Jason Woodworth 《Journal of Animal Science and Biotechnology》 SCIE CAS 2014年第3期251-261,共11页
Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytok... Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytokines that orchestrate the immune response. The classic responses observed with immune system activation and cytokine production include: anorexia, fever, lethargy, recruitment of other immune cells, and phagocytosis. While production of immune system components is known to require some amino acids, increases in amino acid requirements are more than offset by the associated decrease in protein accretion and increased muscle protein degradation that also accompanies immune system activation. However, the biggest impact of cytokine production is a decrease in feed intake. Therefore, as feed intake decreases, the energy needed to drive protein synthesis is also decreased. This suggests that diets should still be formulated on a similar calorie:lysine ratio as those formulated for non-immune challenged pigs. The evidence is sparse or equivocal for increasing nutrient requirements during an immune challenge. Nutritionists and swine producers should resist the pressure to alter the diet, limit feed, or add expensive feed additives during an immune challenge. While immune stimulation does not necessitate changes in diet formulation, when pigs are challenged with non-pathogenic diarrhea there are potential advantages on gut health with the increased use of crystalline amino acids rather than intact protein sources (i.e., soybean meal). This is because reducing crude protein decreases the quantity of fermentable protein entering the large intestine, which lowers post weaning diarrhea. It also lowers the requirement for expensive specialty protein sources or other protein sources such as soybean meal that present immunological challenges to the gut. The objective of this review is two-fold. The first is to discuss immunity by nutrition interactions, or lack thereof, and secondly, to review amino acid requirement estimates for nursery pigs. 展开更多
关键词 Amino acids IMMUNITY PIGS requirements
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Applying CBR to Machine Tool Product Configuration Design Oriented to Customer Requirements 被引量:12
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作者 WANG Pengjia GONG Yadong +2 位作者 XIE Hualong LIU Yongxian NEE Andrew Yehching 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第1期60-76,共17页
Product customization is a trend in the current market-oriented manufacturing environment. However, deduction from customer requirements to design results and evaluation of design alternatives are still heavily relian... Product customization is a trend in the current market-oriented manufacturing environment. However, deduction from customer requirements to design results and evaluation of design alternatives are still heavily reliant on the designer's experience and knowledge. To solve the problem of fuzziness and uncertainty of customer requirements in product configuration, an analysis method based on the grey rough model is presented. The customer requirements can be converted into technical characteristics effectively. In addition, an optimization decision model for product planning is established to help the enterprises select the key technical characteristics under the constraints of cost and time to serve the customer to maximal satisfaction. A new case retrieval approach that combines the self-organizing map and fuzzy similarity priority ratio method is proposed in case-based design. The self-organizing map can reduce the retrieval range and increase the retrieval efficiency, and the fuzzy similarity priority ratio method can evaluate the similarity of cases comprehensively. To ensure that the final case has the based on grey correlation analysis is proposed to evaluate similar cases best overall performance, an evaluation method of similar cases to select the most suitable case. Furthermore, a computer-aided system is developed using MATLAB GUI to assist the product configuration design. The actual example and result on an ETC series machine tool product show that the proposed method is effective, rapid and accurate in the process of product configuration. The proposed methodology provides a detailed instruction for the product configuration design oriented to customer requirements. 展开更多
关键词 customer requirements case-based reasoning machine tool case retrieval case evaluation computer-aided system
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Nutrient uptake requirements with increasing grain yield for rice in China 被引量:4
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作者 CHE Sheng-guo ZHAO Bing-qiang +4 位作者 LI Yan-ting YUAN Liang LIN Zhi-an HU Shu-wen SHEN Bing 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第4期907-917,共11页
Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative inf... Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative influences, especially under high-yielding intensive systems. A database involving rice grain yields, nutrient concentrations and accumulations collected from on-field station experiments in the literatures published from 2000 to 2013 in China was developed to understand the relationships between grain yields and plant nutrient uptakes, and to quantify nutrient requirements for different yield levels. Considering all data sets, rice grain yield ranged from 1.4 to 15.2 t ha^-1 with the mean value of 7.84 t ha^-1, and ca. 10.4% of yield observa- tions were higher than the yield barrier level of 10 t ha^-1. N requirement to produce one ton grain was 21.10 kg for the yield range 〈4.0 t ha^-1 with a high variation of 45.8%. Except of the yield range 〈4.0 t ha^-1, the values of N requirement, firstly increased from 18.78 kg for yield range 4.0-5.5 t ha^-1 to 20.62 kg for yield range 7.0-8.5 t ha^-1, then decreased slightly to 19.67 and 19.17 kg for the yield range 8.5-10 and 〉10 t ha^-1, respectively. Phosphorus (P) and potassium (K) requirements showed increasing trends, from 3.51 and 19.87 kg per t grain for 〈4.0 t ha^-1 yield range to 4.10 and 21.70 kg for 〉10.0 t ha^-1 range. In conclusion, nutrient requirement varied with increasement of grain yield, and N, P and K presented various response trends, increasing, declining or stagnating, which would be of great benefit for improving fertilizer strategies. 展开更多
关键词 RICE nutrient requirement nitrogen PHOSPHORUS POTASSIUM
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Geochemical Mapping:With Special Emphasis on Analytical Requirements 被引量:5
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作者 XIE Xuejing CHENG Hangxin LIU Dawen 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第2期451-462,共12页
More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 t... More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 to 1992, the International Geochemical Mapping project (Project 259 of UNESCO's IGCP Program) prepared recommendations designed to standardize geochemical mapping methods. The analytical requirements are an essential component of the overall recommendations. They included the following: 71 elements should be analyzed in future mapping projects; the detection limits of trace and ultratrace elements must be lower than the corresponding crustal abundances; and the Chinese GSD and Canadian STSD standard sample series should be used for the correlation of global data. A proposal was also made to collect 5000 composite samples, at very low sampling densities to cover the whole Earth's land surface. In 1997 an IUGS Working Group on Global Geochemical Baselines was formed to continue the work which began with IGCP 259. From 1997 up to now, new progress has been made especially in China and FOREGS countries under the aegis of this working group, including the study of suitable sampling media, development of a multi-element analytical system, new proficiency test for selection of competent laboratories and role of wide-spaced mapping in mineral exploration. One of the major problems awaiting solution has been the inability of many laboratories to meet the IGCP recommendations to generate high quality geochemical maps. Fortunately several laboratories in China and Europe have demonstrated an ability to meet the requirements and they will be well placed to render technical assistance to other countries. 展开更多
关键词 geochemical mapping geoanalysis analytical requirement extremely low density sampling
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Aerodynamic Characteristics,Power Requirements and Camber Effects of the Pitching-Down Flapping Hovering 被引量:4
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作者 Peng Bai,Er-jie Cui,Hui-ling ZhanChina Academy of Aerospace Aerodynamics,Beijing 100074,P.R.China 《Journal of Bionic Engineering》 SCIE EI CSCD 2009年第2期120-134,共15页
The pitching-down flapping is a new type of bionic flapping,which was invented by the author based on previous studies on the aerodynamic mechanisms of fruit fly(pitching-up)flapping.The motivation of this invention i... The pitching-down flapping is a new type of bionic flapping,which was invented by the author based on previous studies on the aerodynamic mechanisms of fruit fly(pitching-up)flapping.The motivation of this invention is to improve the aerodynamic characteristics of flapping Micro Air Vehicles(MAVs).In this paper the pitching-down flapping is briefly introduced.The major works include:(1)Computing the power requirements of pitching-down flapping in three modes(advanced,symmetrical, delayed),which were compared with those of pitching-up flapping;(2)Investigating the effects of translational acceleration time,Δτ_t,and rotational time,Δτ_r,at the end of a stroke,and the angle of attack,α,in the middle of a stroke on the aerodynamic characteristics in symmetrical mode;(3)Investigating the effect of camber on pitching-down flapping.From the above works, conclusions can be drawn that:(1)Compared with the pitching-up flapping,the pitching-down flapping can greatly reduce the time-averaged power requirements;(2)The increase in Δτt and the decrease in Δτ_r can increase both the lift and drag coefficients, but the time-averaged ratio of lift to drag changes a little.And α has significant effect on the aerodynamic characteristics of the pitching-down flapping;(3)The positive camber can effectively increase the lift coefficient and the ratio of lift to drag. 展开更多
关键词 aerodynamic characteristics flapping wing power requirements camber effect pitching-down-flapping MAVS
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