As the trend to use the latestmachine learning models to automate requirements engineering processes continues,security requirements classification is tuning into the most researched field in the software engineering ...As the trend to use the latestmachine learning models to automate requirements engineering processes continues,security requirements classification is tuning into the most researched field in the software engineering community.Previous literature studies have proposed numerousmodels for the classification of security requirements.However,adopting those models is constrained due to the lack of essential datasets permitting the repetition and generalization of studies employing more advanced machine learning algorithms.Moreover,most of the researchers focus only on the classification of requirements with security keywords.They did not consider other nonfunctional requirements(NFR)directly or indirectly related to security.This has been identified as a significant research gap in security requirements engineering.The major objective of this study is to propose a security requirements classification model that categorizes security and other relevant security requirements.We use PROMISE_exp and DOSSPRE,the two most commonly used datasets in the software engineering community.The proposed methodology consists of two steps.In the first step,we analyze all the nonfunctional requirements and their relation with security requirements.We found 10 NFRs that have a strong relationship with security requirements.In the second step,we categorize those NFRs in the security requirements category.Our proposedmethodology is a hybridmodel based on the ConvolutionalNeural Network(CNN)and Extreme Gradient Boosting(XGBoost)models.Moreover,we evaluate the model by updating the requirement type column with a binary classification column in the dataset to classify the requirements into security and non-security categories.The performance is evaluated using four metrics:recall,precision,accuracy,and F1 Score with 20 and 28 epochs number and batch size of 32 for PROMISE_exp and DOSSPRE datasets and achieved 87.3%and 85.3%accuracy,respectively.The proposed study shows an enhancement in metrics values compared to the previous literature studies.This is a proof of concept for systematizing the evaluation of security recognition in software systems during the early phases of software development.展开更多
The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education....The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education.To do so,there is a need to understand the impact of LLMs on software engineering education.In this paper,we conducted a preliminary case study on three software requirements engineering classes where students are allowed to use LLMs to assist in their projects.Based on the students’experience,performance,and feedback from a survey conducted at the end of the courses,we characterized the challenges and benefits of applying LLMs in software engineering education.This research contributes to the ongoing discourse on the integration of LLMs in education,emphasizing both their prominent potential and the need for balanced,mindful usage.展开更多
Communications system has a signifi-cant impact on both operational safety and logisti-cal efficiency within low-altitude drone logistics net-works.Aiming at providing a systematic investiga-tion of real-world communi...Communications system has a signifi-cant impact on both operational safety and logisti-cal efficiency within low-altitude drone logistics net-works.Aiming at providing a systematic investiga-tion of real-world communication requirements and challenges encountered in Meituan UAV’s daily oper-ations,this article first introduces the operational sce-narios within current drone logistics networks and an-alyzes the related communication requirements.Then,the current communication solution and its inherent bottlenecks are elaborated.Finally,this paper explores emerging technologies and examines their application prospects in drone logistics networks.展开更多
China's perfume market has been experiencing significant growth.The “2024 China Perfume and Fragrance White Paper”,jointly published by Eternal Group,DSM-Firmenich,and Ipsos in September 2024,reveals that the ma...China's perfume market has been experiencing significant growth.The “2024 China Perfume and Fragrance White Paper”,jointly published by Eternal Group,DSM-Firmenich,and Ipsos in September 2024,reveals that the market surged from 11.4 billion yuan in 2018 to 22.9 billion yuan in 2023,achieving a compound annual growth rate(CAGR) of 15%.With projections estimating a rise to 44 billion yuan by 2028 at a 14% CAGR,the sector's long-term growth prospects remain strong.展开更多
As emerging services continue to be explored,indoor communications geared towards different user requirements will face severe challenges such as larger penetration losses and more critical multipath issues,leading to...As emerging services continue to be explored,indoor communications geared towards different user requirements will face severe challenges such as larger penetration losses and more critical multipath issues,leading to difficulties in achieving flexible coverage.In this paper,we introduce transmissive reconfigurable intelligent surfaces(RISs)as intelligent passive auxiliary devices into indoor scenes,replacing conventional ultra-dense small cell and relay forwarding approaches to address these issues at low deployment and operation costs.Specifically,we study the optimization design of active and passive beamforming for the transmissive RISs-aided indoor multiuser downlink communication systems.This involves considering more realistic indoor congestion modeling and near-field propagation characteristics.The goal of our optimization is to minimize the total transmit power at the access point(AP)for different user service requirements,including quality-of-service(QoS)and wireless power transfer(WPT).Due to the nonconvex nature of the optimization problem,adaptive penalty coefficients are imported to solve it alternatively with closed-form solutions for both active and passive beamforming.Simulation results demonstrate that the use of transmissive RISs is indeed an efficient way to achieve flexible coverage in indoor scenarios.Furthermore,the proposed optimization algorithm has been proven to be effective and robust in achieving energy-saving transmission.展开更多
Conventional proton exchange membrane(PEM)electrolysis technology relies on ultrapure water,as cationic impurities(such as Na^(+),Ca^(2+) and Fe^(3+))can occupy H+transport sites in the membrane[1],leading to a sharp ...Conventional proton exchange membrane(PEM)electrolysis technology relies on ultrapure water,as cationic impurities(such as Na^(+),Ca^(2+) and Fe^(3+))can occupy H+transport sites in the membrane[1],leading to a sharp rise in cathode pH,catalyst deactivation,and membrane degradation[2].This forces the system to be equipped with complex water purification equipment and even necessitates the replacement of membrane electrode assemblies(MEAs),increasing the levelized cost of hydrogen(LCOH)[3].To address this,Tao Ling's group recently proposed a"local pH regulation"strategy in Nature Energy[4].展开更多
The sugarcane is a main sugar crop in China. The seasonal drying is one of the problems that influence the improvement of output and quality of sugarcane in China. The experimental results for the water requirement an...The sugarcane is a main sugar crop in China. The seasonal drying is one of the problems that influence the improvement of output and quality of sugarcane in China. The experimental results for the water requirement and fertigation of the sugarcane showed, that the distribution of the rainfall in spring, autumn and winter, all could not suit the requirements for sugarcane growth. Detailedly, it can suit that sugarcane requirement of 74.4%, 68.6% and 35.7% respectively at seedling emerging stage, tillering stage and mature stage according to sugarcane growth. The drought has already limited the yield of sugarcane. Application of fertigation can enhance the fertilizer use efficiency, and it is also a water saving technique in sugarcane production.展开更多
Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these pr...Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.展开更多
With ＇Hongmanao＇, a sweet cherry cultivar from central Shanxi Province, as the experimental material, the chilling requirements of different types of fruit branches （including mixed fruit branch, long fruit branch,...With ＇Hongmanao＇, a sweet cherry cultivar from central Shanxi Province, as the experimental material, the chilling requirements of different types of fruit branches （including mixed fruit branch, long fruit branch, medium fruit branch, short fruit branch and blossom fruit branch） were studied by the 0-7.2 ℃ model in a solar greenhouse during 2012-2013. In the greenhouse, the fruit branches of ＇Hongmanao＇ were cultured in water in a thermostatic environment. The results showed that the chilling requirement of leaf buds of ＇Hongmanao＇ was lower than that of its flower buds; and the chilling requirements of the five types of fruit branches ranked as blossom fruit branch＇s〈short fruit branch＇s〈medium fruit branch＇s〈long fruit branch＇s〈mixed fruit branch＇s,展开更多
[Objective] This study aimed to explore the characteristics of ecological water requirement in Maijishan Scenic Spot. [Methed] The characteristics of ecologi- cal water requirement in Maijishan Scenic Spot were analyz...[Objective] This study aimed to explore the characteristics of ecological water requirement in Maijishan Scenic Spot. [Methed] The characteristics of ecologi- cal water requirement in Maijishan Scenic Spot were analyzed based on,the data of soil humidity and meteorology of the spot. [Result] The result showed that the actual annual ecological water requirement in the spot was 678×10^6 m^3, and the proportion of soil water and evapotranspiration were 21% and 79%, respectively; the minimum annual ecological water requirement quota in the spot was 480.27×10^6 m^3, and the proportion of soil water and evapotranspiration were 16% and 84%, respectively; the minimum annual suitable ecological water requirement quota in the spot was 624.22×10^6 m^3, and the proportion of soil water and evapotranspiration were 18% and 82%, respectively. The precipitation was 614×10^6 m^3, and consumptive water surplus reached up to 78×10^6 m^3. The years when the precipitation was higher than the evapotranspiration accounted for 76%. Since 1980s, the evapotranspiration showed a linearly increasing trend. The precipitation was higher than the evapotranspiration from Jun. to Oct. and less than the evapotranspiration from Nov. to Dec. and Jan. to May. Evapotranspiration water requirement was regulated by soil water. The dis- parity between precipitation and evapotranspiration was huge in spring, thus having certain influence on waterfalls and streams in the spot. [Conclusion] The results of this study provided a basis for the rational use and long-term planning of the water sources in Maijishan Scenic Spot.展开更多
Along with the emergence of real-time multi-media,interactive service,real-time voice and other services calling for high quality of service,there should be a good network to support those services.Most present route ...Along with the emergence of real-time multi-media,interactive service,real-time voice and other services calling for high quality of service,there should be a good network to support those services.Most present route algo- rithms with computational complexity hardly consider the restriction of node energy,so it degrades the whole capabil- ity of network.Bandwidth guarantee is one of the most crucial factors in real-time application,and this paper brings forward a distributed on-demand QoS routing protocol based on energy and bandwidth requirement.This QoS routing protocol makes use of bandwidth calculation algorithm and analyzes its route mechanism.The simulation results veri- fy its validity.The QoS routing protocol improves the packet delivery fraction and average end-to-end delay,prolongs the network lifetime,enhances the network performance and satisfies the route requirement for ad hoc networks.展开更多
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
In order to analyze and test the component-based web application and decide when to stop the testing process, the concept of coverage criteria and test requirement reduction approach are proposed. First, four adequacy...In order to analyze and test the component-based web application and decide when to stop the testing process, the concept of coverage criteria and test requirement reduction approach are proposed. First, four adequacy criteria are defined and subsumption relationships among them are proved. Then, a translation algorithm is presented to transfer the test model into a web application decision-to-decision graph（WADDGraph）which is used to reduce testing requirements. Finally, different sets of test requirements can be generated from WADDGraph by analyzing subsumption and equivalence relationships among edges based on different coverage criteria, and testers can select different test requirements according to different testing environments. The case study indicates that coverage criteria follow linear subsumption relationships in real web applications. Test requirements can be reduced more than 55% on average based on different coverage criteria and the size of test requirements increases with the increase in the complexity of the coverage criteria.展开更多
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
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
BACKGROUND:In general,the dose requirement and complications of propofol are lower when used in the diluted form than in the undiluted form.The aim of this study was to determine the dose requirement and complications...BACKGROUND:In general,the dose requirement and complications of propofol are lower when used in the diluted form than in the undiluted form.The aim of this study was to determine the dose requirement and complications of diluted and undiluted propofol for deep sedation in endoscopic retrograde cholangiopancreatography.METHODS:Eighty-six patients were randomly assigned to either group D (diluted propofol) or U (undiluted propofol).All patients were sedated with 0.02-0.03 mg/kg midazolam (total dose ≤2 mg for age <70 years and 1 mg for age ≥70) and 0.5-1 μg/kg fentanyl (total dose ≤75 μg for age <70 and ≤50 μg for age ≥70).Patients in group U (42) were sedated with standard undiluted propofol (10 mg/mL).Patients in group D (44) were sedated with diluted propofol (5 mg/mL).All patients in both groups were monitored for the depth of sedation using the Narcotrend system.The primary outcome variable was the total dose of propofol used during the procedure.The secondary outcome variables were complications during and immediately after the procedure,and recovery time.RESULTS:All endoscopies were completed successfully.Mean propofol doses per body weight and per body weight per hour in groups D and U were 3.0 mg/kg,6.2 mg/kg per hour and 4.7 mg/kg,8.0 mg/kg per hour,respectively.The mean dose of propofol,expressed as total dose,dose/kg or dose/kg per hour and the recovery time were not significantly different between the two groups.Sedation-related adverse events during and immediately after the procedure were higher in group U (42.9%) than in group D (18.2%) (P=0.013).CONCLUSIONS:Propofol requirement and recovery time in the diluted and undiluted propofol groups were comparable.However,the sedation-related hypotension was significantly lower in the diluted group than the undiluted group.展开更多
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
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
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
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
基金The authors of this study extend their appreciation to the Researchers Supporting Project number(RSPD2025R544),King Saud University,Riyadh,Saudia Arabia.
文摘As the trend to use the latestmachine learning models to automate requirements engineering processes continues,security requirements classification is tuning into the most researched field in the software engineering community.Previous literature studies have proposed numerousmodels for the classification of security requirements.However,adopting those models is constrained due to the lack of essential datasets permitting the repetition and generalization of studies employing more advanced machine learning algorithms.Moreover,most of the researchers focus only on the classification of requirements with security keywords.They did not consider other nonfunctional requirements(NFR)directly or indirectly related to security.This has been identified as a significant research gap in security requirements engineering.The major objective of this study is to propose a security requirements classification model that categorizes security and other relevant security requirements.We use PROMISE_exp and DOSSPRE,the two most commonly used datasets in the software engineering community.The proposed methodology consists of two steps.In the first step,we analyze all the nonfunctional requirements and their relation with security requirements.We found 10 NFRs that have a strong relationship with security requirements.In the second step,we categorize those NFRs in the security requirements category.Our proposedmethodology is a hybridmodel based on the ConvolutionalNeural Network(CNN)and Extreme Gradient Boosting(XGBoost)models.Moreover,we evaluate the model by updating the requirement type column with a binary classification column in the dataset to classify the requirements into security and non-security categories.The performance is evaluated using four metrics:recall,precision,accuracy,and F1 Score with 20 and 28 epochs number and batch size of 32 for PROMISE_exp and DOSSPRE datasets and achieved 87.3%and 85.3%accuracy,respectively.The proposed study shows an enhancement in metrics values compared to the previous literature studies.This is a proof of concept for systematizing the evaluation of security recognition in software systems during the early phases of software development.
基金supported in part by the Teaching Reform Project of Chongqing University of Posts and Telecommunications,China under Grant No.XJG23234Chongqing Municipal Higher Education Teaching Reform Research Project under Grant No.203399the Doctoral Direct Train Project of Chongqing Science and Technology Bureau under Grant No.CSTB2022BSXM-JSX0007。
文摘The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education.To do so,there is a need to understand the impact of LLMs on software engineering education.In this paper,we conducted a preliminary case study on three software requirements engineering classes where students are allowed to use LLMs to assist in their projects.Based on the students’experience,performance,and feedback from a survey conducted at the end of the courses,we characterized the challenges and benefits of applying LLMs in software engineering education.This research contributes to the ongoing discourse on the integration of LLMs in education,emphasizing both their prominent potential and the need for balanced,mindful usage.
基金supported by Shenzhen Science and Technology Program(KJZD20230923115210021)。
文摘Communications system has a signifi-cant impact on both operational safety and logisti-cal efficiency within low-altitude drone logistics net-works.Aiming at providing a systematic investiga-tion of real-world communication requirements and challenges encountered in Meituan UAV’s daily oper-ations,this article first introduces the operational sce-narios within current drone logistics networks and an-alyzes the related communication requirements.Then,the current communication solution and its inherent bottlenecks are elaborated.Finally,this paper explores emerging technologies and examines their application prospects in drone logistics networks.
文摘China's perfume market has been experiencing significant growth.The “2024 China Perfume and Fragrance White Paper”,jointly published by Eternal Group,DSM-Firmenich,and Ipsos in September 2024,reveals that the market surged from 11.4 billion yuan in 2018 to 22.9 billion yuan in 2023,achieving a compound annual growth rate(CAGR) of 15%.With projections estimating a rise to 44 billion yuan by 2028 at a 14% CAGR,the sector's long-term growth prospects remain strong.
基金supported in part by the Natural Science Basic Research Plan in Shaanxi Province under Grant 2024JC-ZDXM-36in part by the Key Research and Development Program of Shaanxi Province under Grant 2023-YBGY-255+2 种基金in part by the Excellent Youth Science Foundation of Xi’an University of Science and Technology under Grant 2019YQ3-13in part by the Xi’an Key Laboratory of Network Convergence Communications under Grant 2022NCC-K102in part by the Fundamental Research Funds for the Central Universities under Grant QTZX23029。
文摘As emerging services continue to be explored,indoor communications geared towards different user requirements will face severe challenges such as larger penetration losses and more critical multipath issues,leading to difficulties in achieving flexible coverage.In this paper,we introduce transmissive reconfigurable intelligent surfaces(RISs)as intelligent passive auxiliary devices into indoor scenes,replacing conventional ultra-dense small cell and relay forwarding approaches to address these issues at low deployment and operation costs.Specifically,we study the optimization design of active and passive beamforming for the transmissive RISs-aided indoor multiuser downlink communication systems.This involves considering more realistic indoor congestion modeling and near-field propagation characteristics.The goal of our optimization is to minimize the total transmit power at the access point(AP)for different user service requirements,including quality-of-service(QoS)and wireless power transfer(WPT).Due to the nonconvex nature of the optimization problem,adaptive penalty coefficients are imported to solve it alternatively with closed-form solutions for both active and passive beamforming.Simulation results demonstrate that the use of transmissive RISs is indeed an efficient way to achieve flexible coverage in indoor scenarios.Furthermore,the proposed optimization algorithm has been proven to be effective and robust in achieving energy-saving transmission.
基金the Natural Science Foundation of Guangxi,China(No.2021GXNSFBA220058)the National Natural Science Foundation of China(Nos.22272036, 22362008)Guangxi Normal University Research Grant,China(No.2022TD).
文摘Conventional proton exchange membrane(PEM)electrolysis technology relies on ultrapure water,as cationic impurities(such as Na^(+),Ca^(2+) and Fe^(3+))can occupy H+transport sites in the membrane[1],leading to a sharp rise in cathode pH,catalyst deactivation,and membrane degradation[2].This forces the system to be equipped with complex water purification equipment and even necessitates the replacement of membrane electrode assemblies(MEAs),increasing the levelized cost of hydrogen(LCOH)[3].To address this,Tao Ling's group recently proposed a"local pH regulation"strategy in Nature Energy[4].
基金Supported by the National Science and Technology Support Plan(2006BAD05B06-05)IPNI and IPI+3 种基金the Natural Sciences Founda-tion of Guangxi(No.0448023)the Natural Sciences Foundationof Guangxi Academy of Agricultural Sciences(No.2007001(Z))Project Ministry of Agriculture of the people s Republic of China(WX-2-07-13)National Key Technology R&D program(2007BAD30B03)~~
文摘The sugarcane is a main sugar crop in China. The seasonal drying is one of the problems that influence the improvement of output and quality of sugarcane in China. The experimental results for the water requirement and fertigation of the sugarcane showed, that the distribution of the rainfall in spring, autumn and winter, all could not suit the requirements for sugarcane growth. Detailedly, it can suit that sugarcane requirement of 74.4%, 68.6% and 35.7% respectively at seedling emerging stage, tillering stage and mature stage according to sugarcane growth. The drought has already limited the yield of sugarcane. Application of fertigation can enhance the fertilizer use efficiency, and it is also a water saving technique in sugarcane production.
文摘Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.
基金Supported by Key Scientific and Technological Project of Shanxi Science and Technology Department(20150311015-2)Shanxi Key Laboratory of Germplasm Improvement and Utilization in Pomology~~
文摘With ＇Hongmanao＇, a sweet cherry cultivar from central Shanxi Province, as the experimental material, the chilling requirements of different types of fruit branches （including mixed fruit branch, long fruit branch, medium fruit branch, short fruit branch and blossom fruit branch） were studied by the 0-7.2 ℃ model in a solar greenhouse during 2012-2013. In the greenhouse, the fruit branches of ＇Hongmanao＇ were cultured in water in a thermostatic environment. The results showed that the chilling requirement of leaf buds of ＇Hongmanao＇ was lower than that of its flower buds; and the chilling requirements of the five types of fruit branches ranked as blossom fruit branch＇s〈short fruit branch＇s〈medium fruit branch＇s〈long fruit branch＇s〈mixed fruit branch＇s,
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest,China(GYHY201106029)~~
文摘[Objective] This study aimed to explore the characteristics of ecological water requirement in Maijishan Scenic Spot. [Methed] The characteristics of ecologi- cal water requirement in Maijishan Scenic Spot were analyzed based on,the data of soil humidity and meteorology of the spot. [Result] The result showed that the actual annual ecological water requirement in the spot was 678×10^6 m^3, and the proportion of soil water and evapotranspiration were 21% and 79%, respectively; the minimum annual ecological water requirement quota in the spot was 480.27×10^6 m^3, and the proportion of soil water and evapotranspiration were 16% and 84%, respectively; the minimum annual suitable ecological water requirement quota in the spot was 624.22×10^6 m^3, and the proportion of soil water and evapotranspiration were 18% and 82%, respectively. The precipitation was 614×10^6 m^3, and consumptive water surplus reached up to 78×10^6 m^3. The years when the precipitation was higher than the evapotranspiration accounted for 76%. Since 1980s, the evapotranspiration showed a linearly increasing trend. The precipitation was higher than the evapotranspiration from Jun. to Oct. and less than the evapotranspiration from Nov. to Dec. and Jan. to May. Evapotranspiration water requirement was regulated by soil water. The dis- parity between precipitation and evapotranspiration was huge in spring, thus having certain influence on waterfalls and streams in the spot. [Conclusion] The results of this study provided a basis for the rational use and long-term planning of the water sources in Maijishan Scenic Spot.
基金the PhD Programs Foundation of Superior Colleges and Universities(20060611010)International coOperation projects in science and technology of the State Ministry of Science(2007 DFR10420)+1 种基金Science and Technology research projects of Chongqing(CSTC,2006AA7024) and (CSTC,2007AB2041)Natural Science Found of ChongQing(CSTC2007BB2194)
文摘Along with the emergence of real-time multi-media,interactive service,real-time voice and other services calling for high quality of service,there should be a good network to support those services.Most present route algo- rithms with computational complexity hardly consider the restriction of node energy,so it degrades the whole capabil- ity of network.Bandwidth guarantee is one of the most crucial factors in real-time application,and this paper brings forward a distributed on-demand QoS routing protocol based on energy and bandwidth requirement.This QoS routing protocol makes use of bandwidth calculation algorithm and analyzes its route mechanism.The simulation results veri- fy its validity.The QoS routing protocol improves the packet delivery fraction and average end-to-end delay,prolongs the network lifetime,enhances the network performance and satisfies the route requirement for ad hoc networks.
文摘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.
基金The National Natural Science Foundation of China(No.90818027,60873050)the National High Technology Research andDevelopment Program of China (863 Program) (No.2009AA01Z147)+2 种基金Opening Foundation of State Key Laboratory Software Engineering in Wu-han University(No.SKLSE20080717)Opening Foundation of State KeyLaboratory for Novel Software Technology in Nanjing University(No.ZZ-KT2008F12)the Key Laboratory Foundation of Shanghai Municipal Science and Technology Commission (No.09DZ2272600)
文摘In order to analyze and test the component-based web application and decide when to stop the testing process, the concept of coverage criteria and test requirement reduction approach are proposed. First, four adequacy criteria are defined and subsumption relationships among them are proved. Then, a translation algorithm is presented to transfer the test model into a web application decision-to-decision graph（WADDGraph）which is used to reduce testing requirements. Finally, different sets of test requirements can be generated from WADDGraph by analyzing subsumption and equivalence relationships among edges based on different coverage criteria, and testers can select different test requirements according to different testing environments. The case study indicates that coverage criteria follow linear subsumption relationships in real web applications. Test requirements can be reduced more than 55% on average based on different coverage criteria and the size of test requirements increases with the increase in the complexity of the coverage criteria.
基金supported by National Research Initiative Competitive Grants from the Animal Reproduction Program(2008-35203-19120 and 2011-67015-20028)Animal Growth&Nutrient Utilization Program(2008-35206-18764, 2008-35206-18762,2009-35206-05211,and 2014-67015-21770) of the USDA National Institute of Food and Agriculture Texas A&M AgriLife Research(H-8200),Ajinomoto Inc.(Tokyo,Japan),and Gentech Inc. (Shanghai,China)
文摘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.
基金Supported by the National Natural Science F oundation of China(6 98730 35 ) and the Research Fund for the Doctoral Program of Hi
文摘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.
文摘BACKGROUND:In general,the dose requirement and complications of propofol are lower when used in the diluted form than in the undiluted form.The aim of this study was to determine the dose requirement and complications of diluted and undiluted propofol for deep sedation in endoscopic retrograde cholangiopancreatography.METHODS:Eighty-six patients were randomly assigned to either group D (diluted propofol) or U (undiluted propofol).All patients were sedated with 0.02-0.03 mg/kg midazolam (total dose ≤2 mg for age <70 years and 1 mg for age ≥70) and 0.5-1 μg/kg fentanyl (total dose ≤75 μg for age <70 and ≤50 μg for age ≥70).Patients in group U (42) were sedated with standard undiluted propofol (10 mg/mL).Patients in group D (44) were sedated with diluted propofol (5 mg/mL).All patients in both groups were monitored for the depth of sedation using the Narcotrend system.The primary outcome variable was the total dose of propofol used during the procedure.The secondary outcome variables were complications during and immediately after the procedure,and recovery time.RESULTS:All endoscopies were completed successfully.Mean propofol doses per body weight and per body weight per hour in groups D and U were 3.0 mg/kg,6.2 mg/kg per hour and 4.7 mg/kg,8.0 mg/kg per hour,respectively.The mean dose of propofol,expressed as total dose,dose/kg or dose/kg per hour and the recovery time were not significantly different between the two groups.Sedation-related adverse events during and immediately after the procedure were higher in group U (42.9%) than in group D (18.2%) (P=0.013).CONCLUSIONS:Propofol requirement and recovery time in the diluted and undiluted propofol groups were comparable.However,the sedation-related hypotension was significantly lower in the diluted group than the undiluted group.
文摘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.
基金Supported by State Science and Technology Support Program of China(Grant No.2012BAF12B08-04)Liaoning Provincial Key Scientific and Technological Project of China(Grant Nos.2011216010,2010020076-301)
文摘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.
基金supported by the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD11B05)
文摘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.
文摘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.
