Algorithm for Smooth S-curve Feedrate Profiling Generation

The algorithms for feedrate profile generation,such as linear and S-curve profiles,have been widely used in machinery controllers,and these algorithms can greatly improve the smoothness of motion.However,most of the algorithms lead to the discontinuous acceleration/deceleration and jerk,or high jerk levels,which is very harmful to machine tool or robot in most occasions. This paper presents a smooth S-curve feedrate profiling generation algorithm that produces continuous feedrate,acceleration,and jerk profiles.Smooth jerk is obtained by imposing limits on the first and second time derivatives of acceleration,resulting in trapezoidal jerk profiles along the tool path.The discretization of smooth S-curve feedrate is realized with a novel approach that improves the efficiency without calculating the deceleration point in each sampled time.To ensure that the interpolation time is a multiple of the value of sampled time,the feedrate,acceleration,jerk,and jerk derivative are recalculated.Meantime,to improve the efficiency,the interpolation steps of all regions are computed before interpolation.According to the distance of trajectory,the smooth S-curve acceleration and decelerations are divided into three blocks：normal block,short block type-Ⅰ,and short block type-Ⅱ.Finally feedrate discretization of short block type-Ⅰand type-Ⅱis obtained with considering the efficiency.The proposed generation algorithm is tested in machining a part on a five axis milling machine,which is controlled with the CNC system for newly developed high-speed machine tools.The test result shows that the smooth S-curve approach has the smoother feedrate,acceleration,deceleration,and jerk profiles than S-curve.The proposed algorithm ensures the automated machinery motion smoothness,and improves the quality and efficiency of the automated machinery motion planning.

The S-Curve： China versus Its Major Trading Partners

China has been accused of manipulating its currency to gain international competitiveness and enjoy a trade surplus. The S-Curve is a hypothesis that could be used to test the depreciation. It claims that while future effectiveness of currency devaluation or values of the trade balance and current exchange rate are positively correlated, the past values of the trade balance and current exchange rate are negatively correlated. While China＇s aggregate trade flows with the rest of the world conforms to the S-Curve hypothesis, disaggregating trade flows by trading partner reveals that not all partners are affected equally by devaluation. Indeed, trade with 8 out of the 24 partners does not support the S-Curve hypothesis.

基于网站营销的声誉系统的分析

本文分析网站销售的热点问题"声誉系统建设"。针对VC疯狂投资B2C现象,借鉴S-Curve成长曲线原理,提出电子商务建设"声誉维护"问题,并列举实证方案,探讨了销售网站如何通过建立信誉维护系统,渡过产品营销最危险推广期的关键问题,即通过诚信建设,逐渐建立起自己的信誉平台,以最大程度地获得客户的认可和支持,为企业持续发展营造健壮的源动力。

Adaptation of feed rate for 3-axis CNC high-speed machining

To improve the efficiency of CNC machining, assumptive transit circular arc is used to contour two adjacent moves together on the comer to make smooth paths. The radios of transit circular arc can be adjusted with contour accuracy, and the feed rate on the corner can be controlled through limiting the maximum feed rate of transit circular arc segment. A look-ahead algorithm for a series of moves is proposed for speed adjustment in advance, which avoids the occurrence of overload of cutting tool on the comer and reduces the servo track error of parts on the corner or of circular arc move. Equivalent trapezoidal velocity profile is used to analyze the speed of S-curve velocity profile and work out its accurate interpolation, which overcomes the disadvantage of looking up table to calculate feed rate approximately, hence high accuracy and fine surface quality can be obtained while the machining speed is high. The proposed methods can meet the requirements of real-time analysis of high-speed machining. The presented algorithm is effective and has been adopted by CNC system of newly developed high-speed milling machine.

AltBOC navigation signal quality assessment and measurement

In order to ensure that Chinese BeiDou satellite navigation system runs smoothly,the assessment of signal quality has become a significant task.Alternative binary offset carrier(AltBOC)is BeiDou B2 frequency signal.The acquisition of BeiDou signal is processed in off-line mode and the evaluation is performed by taking signal power spectrum,eye diagram,constellation,correlation,loss and s-curve deviation on AltBOC as signal quality evaluation parameters.The results illustrate that the new system signal,namely AltBOC signal,has the best performance in code tracking precision,anti-jamming and anti-multipath.

Planning and Organizing the Projects in Team Co Cakovec, Croatia

The paper systemizes standard methods of planning, monitoring and controlling the realization of construction works in civil engineering projects and overviews the implementation of the methods in Team Co Cakovec from Croatia. The specificities of the methods are shown through the different construction works projects. Also, paper reviews the implementation, modification and improvement of existing methods for planning, monitoring and controlling the realization of projects in Team Co.

Digitally Literate Manager in a Vector Organization

The introduction of IT(information technology)and ISO(International Organization for Standardization)standards into an active organization with a specific management style is not enough for improving the economic principles of a particular business system.However,no significant business progress has been made.Simultaneously,new technologies,including the Internet and AI(artificial intelligence)have been developed as a result of the Fourth Industrial Revolution.Therefore,to be in line with the current trend of n-D dimensional modeling and construction process simulation,construction companies should replace their traditional matrix organizational structures with vector organizational ones.The resource is in the third or vector dimension of organizational structure and allocated by RMs(resource managers).n-D organizational scheme enabling a“daily monitoring”system or daily business system management can be created if all resources are in the time’s fourth dimension.The product of the Fourth Digital Industrial Revolution is a digitally literate manager who oversees the entire business system daily by using his smartphone and utilizing smart technology.This in turn is made possible by ICT(information and communications technology)combined with BIM(building information modeling)tools.The optimization of smart managers is complemented by operational research with a combinatorial equation and simulation of a modified Gauss S-curve project management as a cybernetic method of project simulation.

Codes cross-correlation analysis and data/pilot code pairs optimization for Galileo E1 OS and GPS L1C

The Galileo E1 open service （OS） and the global positioning system （GPS） L1C are intending to use the multiplexed binary offset carrier （MBOC） modulation in E1/L1 band, including both pilot and data components. The impact of data and pilot codes cross-correlation on the distortion of the discriminator function （i.e., the S-curve） is investigated, when only the pilot （or data） components of MBOC signals are tracked. It is shown that the modulation schemes and the receiver configuration （e.g., the correlator spacing） strongly affect the S-curve bias. In this paper, two methods are proposed to optimize the data/pilot code pairs of Galileo E1 OS and GPS L1C. The optimization goal is to obtain the minimum average S-curve bias when tracking only the pilot components a the specific correlator spacing. Figures of merit, such as S-curve bias, correlation loss and code tracking variance have been adopted for analyzing and comparing the un-optimized and optimized code pairs. Simulation results show that the optimized data/pilot code pairs could significantly mitigate the intra-channel codes cross-correlation, and then improve the code tracking performance of MBOC signals.

Sequence Length Limits for Controlling False Positives in Discovering Nucleotide Sequence Motifs

In the study of motif discovery, especially the transcription factor DNA binding sites discovery, a too long input sequence would return non-informative motifs rather than those biological functional motifs. This paper gave theoretical analyses and computational experiments to suggest the length limits of the input sequence. When the sequence length exceeds a certain critical point, the probability of discovering the motif decreases sharply. The work not only gave an explanation on the unsatisfying results of the existed motif discovery problems that the input sequence length might be too long and exceed the point, but also provided an estimation of input sequence length we should accept to get more meaningful and reliable results in motif discovery.

Multiobjective trajectory optimization of intelligent electro-hydraulic shovel

Multiobjective trajectory planning is still face challenges due to certain practical requirements and mul-tiple contradicting objectives optimized simultaneously.In this paper,a multiobjective trajectory optimization approach that sets energy consumption,execution time,and excavation volume as the objective functions is presented for the electro-hydraulic shovel(EHS).The proposed cubic polynomial S-curve is employed to plan the crowd and hoist speed of EHS.Then,a novel hybrid constrained multiobjective evolutionary algorithm based on decomposition is proposed to deal with this constrained multiobjective optimization problem.The normalization of objectives is introduced to minimize the unfavorable effect of orders of magnitude.A novel hybrid constraint handling approach based onε-constraint and the adaptive penalty function method is utilized to discover infeasible solution information and improve population diversity.Finally,the entropy weight technique for order preference by similarity to an ideal solution method is used to select the most satisfied solution from the Pareto optimal set.The performance of the proposed strategy is validated and analyzed by a series of simulation and experimental studies.Results show that the proposed approach can provide the high-quality Pareto optimal solutions and outperforms other trajectory optimization schemes investigated in this article.