Trajectory tracking guidance of interceptor via prescribed performance integral sliding mode with neural network disturbance observer

This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.

Performance Analysis and Optimization of Energy Harvesting Modulation for Multi-User Integrated Data and Energy Transfer

Integrated data and energy transfer(IDET)enables the electromagnetic waves to transmit wireless energy at the same time of data delivery for lowpower devices.In this paper,an energy harvesting modulation(EHM)assisted multi-user IDET system is studied,where all the received signals at the users are exploited for energy harvesting without the degradation of wireless data transfer(WDT)performance.The joint IDET performance is then analysed theoretically by conceiving a practical time-dependent wireless channel.With the aid of the AO based algorithm,the average effective data rate among users are maximized by ensuring the BER and the wireless energy transfer(WET)performance.Simulation results validate and evaluate the IDET performance of the EHM assisted system,which also demonstrates that the optimal number of user clusters and IDET time slots should be allocated,in order to improve the WET and WDT performance.

From EBIT to SEBIT(Sustainable EBIT):Sustainable Performance Accounting(SPA)Using the Example of CO_(2) Accounting

Corporate sustainability reporting has become increasingly important in recent years.However,conventional approaches reach their limits when it comes to quantifying and measuring the actual sustainability performance of a company.This article presents a new approach:Sustainable Performance Accounting(SPA),which is based on an extension of bookkeeping by including ESG bookkeeping.SPA enables companies to systematically measure and manage their sustainability performance.The article provides an overview of the basics of SPA methodology and uses a comprehensive example showing how SPA can be implemented in practice.The article is aimed at interested readers from science and practice as well as decision-makers who are interested in future-oriented sustainability reporting.

Challenges of the Performance Standards of the International Finance Corporation in Financing the African Integrated High-Speed Railway Network and the Way Forward: The Case of Standard Gauge Railway in Tanzania

Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the International Financial Institutions (IFIs). However, conditions provided by the IFIs through the Performance Standards (PS) of the International Financial Corporation (IFC) increase cost of the projects and thus, it becomes a burden to most of the African countries. This study aimed to explore the causes of IFC-PS through the SGR Projects that escalate costs and how to address them. The Tanzania SGR Lot 1 Project that covered 205 km from Dar es Salaam to Morogoro was selected as a case study. The methods used for data collection involved literature review, focus group discussions and interviews. The results and findings show a gap between the IFC-PS and the National Laws and Regulations that escalates costs of the projects if funds from the IFIs were to be secured. To bridge the gap, it is recommended that the African countries should engage into negotiations with the IFIs to agree to waive IFC-PS conditions that escalate costs provided they are adequately covered in the national laws and regulations;engagement of locally established national and regional financial institutions;and the responsible government institutions in the African countries should sit together for assessment and review of the IFC-PS against the national laws and regulations.

Investigating Supply Chain Integration Effects on Environmental Performance in the Jordanian Food Industry

The purpose of this study was to examine the effects of supply chain integration on environmental performance of food manufacturing companies in Jordan. Data for this study were collected from one hundred and nineteen food companies. To answer the study questions, and to verify its hypotheses, descriptive statistical tools and linear regression tests were used. The study results indicated that supply chain integration positively affected environmental performance. Additionally, the results showed that supply chain integration positively affected environmental control and pollution management.

The Impact of the Integration of Culture and Tourism Industry on the Upgrading of Tourism Industry Performance

Based on the provincial data of tourism and cultural industries from 2009 to 2019,this paper studies the impact of the integration of culture and tourism on the economic benefits of regional tourism in China.The results show that:①The integration level of the two industries is generally low in all provinces and regions,and the regional differences are obvious.The integration degree of the central and eastern regions is generally higher than that of the western regions.②The integration degree of culture and tourism has a significant positive impact on the economic benefits of regional tourism.The influence on the central and eastern regions is greater than that on the western regions.③The level of informatization has a positive moderating effect on the economic benefits of regional tourism caused by the integration of culture and tourism.④Government intervention has a negative moderating effect on the economic benefits of tourism.In addition,the level of regional economic development,accessibility and tourism resource endowment are also significant factors affecting the economic benefits of regional tourism.The results show that promoting the deep integration of culture and tourism,promoting the informatization of tourism and moderate government intervention in the industry are conducive to improving the economic benefits of regional tourism.

Research on Application-oriented Undergraduate Course Construction under the Background of Industry-education Integration——Take the Performance Management Course as an Example

Deepening the integration of industry and education is an effective way to cultivate high-quality applied talents.However,integration of industry and education is still at a relatively low level,and the mode is relatively single,without realizing the deep integration of collaborative education and industry.This paper takes the course"Performance Management"of Human Resource Management as an example to build an industry-education integration system with curriculum construction as a carrier.We introduce enterprise tutors and enterprise scenarios from the aspects of teaching syllabus,teaching content,teaching design,teaching process,teaching resources,and teaching evaluation to study the construction of professional courses under the background of industry-education integration.Through the Performance Management course study,we summarize the methods and modes of industry-education integration in human resource management(HRM)courses and extend and apply the research results to other courses of HRM majors to complete the construction of courses aiming at industry-education integration in HRM majors.

Effect of Machined Surface Integrity on Fatigue Performance of Metal Workpiece:A Review

Fatigue performance is a serious concern for mechanical components subject to cyclical stresses,particularly where safety is paramount.The fatigue performance of components relies closely on their surface integrity because the fatigue cracks generally initiate from free surfaces.This paper reviewed the published data,which addressed the effects of machined surface integrity on the fatigue performance of metal workpieces.Limitations in existing studies and the future directions in anti-fatigue manufacturing field were proposed.The remarkable surface topography(e.g.,low roughness and few local defects and inclusions)and large compressive residual stress are beneficial to fatigue performance.However,the indicators that describe the effects of surface topography and residual stress accurately need further study and exploration.The effect of residual stress relaxation under cycle loadings needs to be precisely modeled precisely.The effect of work hardening on fatigue performance had two aspects.Work hardening could increase the material yield strength,thereby delaying crack nucleation.However,increased brittleness could accel-erate crack propagation.Thus,finding the effective control mechanism and method of work hardening is urgently needed to enhance the fatigue performance of machined components.The machining-induced metallurgical structure changes,such as white layer,grain refinement,dislocation,and martensitic transformation affect the fatigue performance of a workpiece significantly.However,the unified and exact conclusion needs to be investigated deeply.Finally,different surface integrity factors had complicated reciprocal effects on fatigue performance.As such,studying the comprehensive influence of surface integrity further and establishing the reliable prediction model of workpiece fatigue performance are meaningful for improving reliability of components and reducing test cost.

Computational Analysis of Performance for Heterogeneous Integrated System with Test Automation

Heterogeneity is inevitable in enterprises due to their various input requirements. The usage of proprietary integration products results in the increased cost of enterprises. During the integration, the focus area has been found to often address only the functional requirements, while the non-functional requirements are side-stepped during the initial stages of a project. Moreover, the use of proprietary integration products and non-standards-based integration platform has given rise to an inflexible integration infrastructure resulting in adaptability concerns. Web services-based integration, based on open standards, is deemed to be the only feasible solution in such cases. This paper explains the performance analysis of enterprise integration in heterogeneous environments for the distributed and the transactional applications. The analysis presented in this paper is seen as a step towards making intelligent decisions well in advance when choosing the integration mechanism/products to address the functional as well as the non-functional requirements considering the future integration needs.

The hydraulic performance and structural integrity of A-Jack armour layer

A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics:(1)recent hydraulic model studies,(2)alternative fabrication methods,and(3)bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods,and also the bundle placement method.In bundle placement,3~20 A-Jacks are banded together,lifted with a spreader bar,and placed as a single crane pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability in random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 m.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A- Jacks may also be cast in a single piece using 'clam shell' type forms.

DCFl-Checker： Checking Kernel Dynamic Control Flow Integrity with Performance Monitoring Counter

It is a challenge to verify integrity of dynamic control flows due to their dynamic and volatile nature.To meet the challenge,existing solutions usually implant an "attachment" in each control transfer.However,the attachment introduces additional cost except performance penalty.For example,the attachment must be unique or restrictedly modified.In this paper,we propose a novel approach to detect integrity of dynamic control flows by counting executed branch instructions without involving any attachment.Our solution is based on the following observation.If a control flow is compromised,the number of executed branch instructions will be abnormally increased.The cause is that intruders usually hijack control flows for malicious execution which absolutely introduces additional branch instructions.Inspired by the above observation,in this paper,we devise a novel system named DCFIChecker,which detect integrity corruption of dynamic control flows with the support of Performance Monitoring Counter(PMC).We have developed a proof-of-concept prototype system of DCFI-Checker on Linux fedora 5.Our experiments with existing kernel rootkits and buffer overflow attack show that DCFIChecker is effective to detect compromised dynamic control transfer,and performance evaluations indicate that performance penalty induced by DCFI-Checker is acceptable.

多物理场耦合下FCM堆内行为研究

为研究全陶瓷包覆弥散燃料(FCM)堆内行为,评价FCM芯块的安全性能,优化FCM芯块结构设计,本文采用二维特征模型模拟FCM芯块的热-力学行为,通过计算不同位置TRISO颗粒的内压,作为输入条件,模拟缓冲层的变形将核芯和缓冲层去除,解决了多颗粒映射的难题。通过调整FCM结构参数,计算了不同结构对FCM芯块性能的影响,实现了FCM芯块的结构优化。研究结果表明,在压水堆环境下,FCM芯块中基体最高温度随运行时间迅速增大,在100天左右时温度达到稳定最高温度约为1390K,低于SiC分解温度。SiC基体的环向应力较高,最高可达1200 MPa,远高于SiC的断裂强度,因此基体在运行过程中开概率率较大。TRISO颗粒中SiC层的环向应力较小,最大应力约为180 MPa,具有较低的失效概率(9×10^(-5)),保证了SiC层的结构完整性。此外,当无燃料区尺寸为400μm时,SiC层的失效概率约为2.0×10^(-5),保证了SiC层的完整性。因此,本研究建立的FCM芯块分析方法,为FCM芯块的工程应用和结构优化奠定了基础。

An Overview of Performance Characteristics, Experiencesand Trends of Aerospace Engine Bearings Technologies

In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today＇s material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH ＆ Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.

Investigation Into the Market-Orientated New Product Development Performance

The effect that the market orientation brings to product innovation performance is reported and the degree of product innovativeness is explored. The interdepartmental integration inside the company is also investigated. A series of hypotheses were developed aiming at presenting a conceptual framework to clarify how market orientation contributes to product innovation performance-moderated by the degree of product innovativeness and affected by the interdepartmental integration. Survey data from 36 business units were analyzed based on the respondents in the research. The statistic results suggest a substantial positive effect of market orientation on product innovation performance. Under the condition of incremental innovativeness among the samples, the more innovative the product is, the more improvements in product innovation performance would be achieved. A variety of particular interdepartmental integration mechanisms have been certified to lend more supports to establishing market orientation and improving product innovation performance.

Microstructure and Wear Performance of High Volume Fraction Carbide M_7C_3 Reinforced Fe-based Composite Coating Fabricated by Plasma Transferred Arc Welding

The fabrication of high volume fraction （HVF） M7C3 （M=Cr, Fe） reinforced Fe-based composite coating on ASTM A36 steel plate using plasma transferred arc （PTA） welding was studied. The results showed that the volume fraction of carbide M7C3 was more than sixty percent, and the relative wear resistance of the coating tested on a block-on-ring dry sliding tester at constant load （100 N） and variable loads （from 100 to 300 N） respectively was about 9 and 14 times higher than that of non-reinforced a-Fe coating. In addition, under constant load condition the friction coefficients （FCs） of two coatings increased first and then decreased with increasing sliding distance. However, under variable loads condition the FCs of non-reinforced a-Fe based coating increased gradually, while that of HVF MTC3 reinforced coating decreased as the load exceeded 220 N. The worn surface of non-reinforced a-Fe based coating was easily deformed and grooved, while that of the HVF M7C3 reinforced coating was difficult to be deformed and grooved.

Integration of Commercial Microbiological Products into Soil Fertility Practices as a Potential Option for Acclimatization and Growth of TC Banana in Kenya

Tissue culture (TC) banana plantlets at the in vitro stage are delicate and devoid of microbes and nutrients that are essential for establishment and subsequent growth. Some microbes are known for function best under certain soil threshold levels of macro and micronutrients and have been associated with growth and performance of TC banana. A green house and field study was conducted to evaluate the effect of combining two commercial biological products [Rhizatech and ECO-T (mycorrhiza and Trichoderma based products, respectively)] with various sources of nitrogen and phosphorous including Mavuno, Minjingu phosphate rock, Calcium Ammonium Nitrate (CAN), manure and diammonium phosphate (DAP) on growth and performance of TC banana in Vertisol and Rhodic Ferralsol soil conditions. Tissue culture plants were initially inoculated with Rhizatech and ECO-T at the acclimatization stage and subsequently at the beginning of the potting stage and field establishment. Addition of nutrient sources was also done at the same stages of plant growth by mixing with the soil substrates prior to planting. The performance of plants was significantly (at p ≤ 0.05) affected by the combinations of nutrient sources depending on the soil type and stage of plant development. The growth of plants in the Vertisol increased with Trichoderma combined with either organic manure, DAP or combined with a macro and micro nutrient source (Mavuno) as compared to the sole application of Trichoderma. Performance of plants treated with combination of mycorrhiza and either Mavuno and minjigu rock phosphate was consistently higher in the Rhodic Ferralsol than either mycorrhiza alone or fertilizer alone. This indicates that TC plants could highly benefit from combined application of microbiological products and inorganic and organic fertilizers. However, a prior knowledge of the product’s microbial formulation and prevailing soil conditions is essential for optimizing the potential benefits of integrating microbe-based product with inorganic and organic fertilizers.

指数有界双连续n阶m次积分C群的指数公式

利用经典算子半群理论中的研究方法,基于指数有界双连续n阶m次积分C群和预解式的定义,给出指数有界双连续n阶m次积分C群与其预解式间积分的表示关系,得到指数有界双连续n阶m次积分C群的指数公式,从而推广了n阶m次积分C半群的相关结果,丰富了算子半群理论的研究内容.

Thermo-Flow Performances for the Main-Auxiliary Integrated Natural Draft Dry Cooling System

Recently,natural draft dry cooling system with the main-auxiliary integrated air-cooled heat exchangers in the up and lower layers,has drawn attention to the electric power industry.This research firstly develops two physical models for the integrated cooling system,namely Case A and Case B.In Case A,the main air-cooled heat exchanger is arranged in the upper layer and the auxiliary air-cooled heat exchanger arranged in the lower layer,while in Case B,the two heat exchanger systems are arranged in the opposite way.And then,directing at the engineering TMCR and TRL 1 working conditions,the unit-local-overall thermo-flow characteristics of Case A and Case B are obtained and compared by numerical simulation.The findings show that,for the auxiliary air-cooled exchanger,Case A has obviously higher cooling performances than Case B,with the difference varying from 5.46%to 7.55%.Whereas,for the main air-cooled exchanger,Case B shows the recovered cooling performances,with the difference changing from 1.15%to 2.99%.Case A is preferably recommended to the engineering application in consideration of more strict cooling demand of the auxiliary cooling system.Conclusively,this research will provide some theoretical guidelines for the design and construction of the main-auxiliary integrated natural draft dry cooling system.

Multi-Model Approach for Assessing the Influence of Calibration Criteria on the Water Balance in Ouémé Basin

Hydrological models are very useful tools for evaluating water resources, and the hydroclimatic hazards associated with the water cycle. However, their calibration and validation require the use of performance criteria which choice is not straightforward. This paper aims to evaluate the influence of the performance criteria on water balance components and water extremes using two global rainfall-runoff models (HBV and GR4J) over the Ouémé watershed at the Bonou and Savè outlets. Three (3) Efficacy criteria (Nash, coefficient of determination, and KGE) were considered for calibration and validation. The results show that the Nash criterion provides a good assessment of the simulation of the different parts of the hydrograph. KGE is better for simulating peak flows and water balance elements than other efficiency criteria. This study could serve as a basis for the choice of performance criteria in hydrological modelling.