Cascading Style Sheets (CSS) is a W3C specification for a style sheet language used for describing the presentation of a document written in a markup language, more precisely, for styling Web ...documents. However, in the last few years, the landscape for CSS development has changed dramatically with the appearance of several languages and tools aiming to help developers build clean, modular and performance-aware CSS. These new approaches give developers mechanisms to preprocess CSS rules through the use of programming constructs, defined as CSS preprocessors, with the ultimate goal to bring those missing constructs to the CSS realm and to foster stylesheets structured programming. At the same time, a new set of tools appeared, defined as postprocessors, for extension and automation purposes covering a broad set of features ranging from identifying unused and duplicate code to applying vendor prefixes. With all these tools and techniques in hands, developers need to provide a consistent workflow to foster CSS modular coding. This paper aims to present an introductory survey on the CSS processors. The survey gathers information on a specific set of processors, categorizes them and compares their features regarding a set of predefined criteria such as: maturity, coverage and performance. Finally, we propose a basic set of best practices in order to setup a simple and pragmatic styling code workflow.
The requirements on preproduction and the control software for various digital machining systems (numerically controlled machine tools, robot manipulators, additive manufacturing equipment) in ...flexible production are considered. By analysis of existing programming languages for digital equipment, UNCL (Uniform Numeric Control Language) has been developed for standard representation of control commands. The use of UNCL in verifying program operation on a machining simulator is considered. Software for the translation of control programs (specified in CLDATA formats and in ISO code) to the invariant format of the universal language is described. The postprocessing of control software from the universal language into programs in commonly used digital control systems is also considered.
This research deals with tool compensation and postprocessor development for numerical control application. The content consists of three main activities. First, derives a cutting location expression ...of the tool for compensation and machining stability use. Second, establishes an analytical methodology to develop a kinematics transformation algorithm (KTA) for the specific type machine with a swivel spindle head and two rotary tables. And last, defines correspondent between workpiece and the cutter to attain the aim of three-dimensional tool compensation and presents postprocessors under KTA for two types of five-axis machine centers in examples.
New three-axis CNC turning machines have been installed on shop floors of factories in the last few years. Although the machines are still particularly adapted to cylindrical work, they are also used ...for non-cylindrical machining. The third axis, C or Y, and separately driven, additional milling cutters have eliminated traditional limitations and opened new machining possibilities, i.e. turning and milling the non-rotational shapes. Even the advanced, integrated CAD/CAM systems do not support the milling and turning processes on three-axis CNC lathes or turning centers. Manual part programming for such machine tools, if available, does not facilitate the integration between design and manufacturing. For accurate part programming on three-axis lathes a new interpolation scheme must be applied, using both spiral segments of Archimedes and circular segments rather than linear segments as applied in CNC milling. Specialized, built-in software developed for the three-axis lathes enables to expand CAD/CAM integration to the same extent as in CNC multi-axis milling. The software includes modified postprocessors for three-axis lathes as well. The integrated processes of design and manufacturing are the most important prerequisites for effective concurrent engineering. In general, it means both better economics and quality of complex products, e.g. shaped rolls for rolling operations, cams and camshafts (non-ruled surfaces included), non-rotational shafts, airscrews, prostheses for total hip replacements, etc.
Automation of graphical dependencies presentation in ANSYS Melnyk, Mykhaylo; Denysyuk, Pavlo; Vitovskyy, Oleh ...
2010 Proceedings of VIth International Conference on Perspective Technologies and Methods in MEMS Design,
2010-April
Conference Proceeding
Presented algorithm automation of graphical dependencies in ANSYS environment.
The simulation of chemical kinetics involving multiple scales constitutes a modeling challenge (from ordinary differential equations to Markov chains) and a computational challenge (multiple scales, ...large dynamical systems, time step restrictions). In this paper, we propose a new discrete stochastic simulation algorithm: the postprocessed second kind stabilized orthogonal τ-leap Runge–Kutta method (PSK-τ-ROCK). In the context of chemical kinetics, this method can be seen as a stabilization of Gillespie's explicit τ-leap algorithm combined with a postprocessor. The stabilized procedure allows to simulate problems with multiple scales (stiff), while the postprocessing procedure allows to approximate the invariant measure (e.g. mean and variance) of ergodic stochastic dynamical systems. We prove stability and accuracy of the PSK-τ-ROCK for a reference system. Numerical experiments illustrate the high reliability and efficiency of the scheme when compared to other τ-leap methods.
•Optimal explicit stabilized scheme for chemical kinetics.•Inexpensive ergodic accurate postprocessor.•Explicit scheme for stiff chemical kinetics problems.•Stabilized tau-leap method.
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•ECMWF ensemble reforecasts of precipitation and temperature were tested for biases.•An attempt was made to reduce these biases through statistical post-processing.•This resulted in ...modest improvements in the quality of the forcing ensembles.•The effect on streamflow ensembles was explored by verifying against simulated flow.•At all spatial scales considered, the improvements in streamflow quality were modest.
The ECMWF temperature and precipitation ensemble reforecasts are evaluated for biases in the mean, spread and forecast probabilities, and how these biases propagate to streamflow ensemble forecasts. The forcing ensembles are subsequently post-processed to reduce bias and increase skill, and to investigate whether this leads to improved streamflow ensemble forecasts. Multiple post-processing techniques are used: quantile-to-quantile transform, linear regression with an assumption of bivariate normality and logistic regression. Both the raw and post-processed ensembles are run through a hydrologic model of the river Rhine to create streamflow ensembles. The results are compared using multiple verification metrics and skill scores: relative mean error, Brier skill score and its decompositions, mean continuous ranked probability skill score and its decomposition, and the ROC score. Verification of the streamflow ensembles is performed at multiple spatial scales: relatively small headwater basins, large tributaries and the Rhine outlet at Lobith. The streamflow ensembles are verified against simulated streamflow, in order to isolate the effects of biases in the forcing ensembles and any improvements therein. The results indicate that the forcing ensembles contain significant biases, and that these cascade to the streamflow ensembles. Some of the bias in the forcing ensembles is unconditional in nature; this was resolved by a simple quantile-to-quantile transform. Improvements in conditional bias and skill of the forcing ensembles vary with forecast lead time, amount, and spatial scale, but are generally moderate. The translation to streamflow forecast skill is further muted, and several explanations are considered, including limitations in the modelling of the space–time covariability of the forcing ensembles and the presence of storages.
•A unique successful postprocessor for a hybrid parallel-serial machine tool is developed.•Smart machining must be accomplished without forcing the tool to make sharp turns when HSM controls detect a ...turn approaching.•NC codes are recalculated to form a new path for the pivot that can avoid the discretization near the singularity points in this study.•The novelty of the paper is successfully to propose a new hybrid parallel-serial five-axis machining model.•The manufacturers that are interested in integrating the inverse kinematics into the design process of their hybrid product.
Instead of obsessively emphasizing to interpolate more points from the linearization algorithm, the NC codes are recalculated to form a new path for the pivot that can avoid the discretization near the singularity points in this study. In previous studies, orientable-spindle machines were directly used to generate smooth tool paths traversing singular positions through inverse kinematics. In many characteristics and practices, PKMs (parallel kinematic machines) and serial machines are the opposites of each other. Fully PKMs have relatively very limited working-space, especially in terms of orientation characteristics. Fully serial machines have a problem of error accumulation. This paper presents a modular method to construct a postprocessor system for a novel hybrid parallel-serial five-axis machine tool. A hybrid parallel-serial mathematical model is introduced to analyze a structural configuration. The configuration decomposition of machine tools is used to create the kernel of the postprocessor. The proposed modified Denavit–Hartenberg notation is used in the coordinate conversion procedure, and then an algorithm is used for developing the inverse kinematics of five-axis machines. The feasibility of solutions depends on the surface normal along the tool path satisfying certain orientation constraints. The proposed algorithm can be easily adapted to convert between cutter contact path and cutter location code and implemented on computer-aided design and computer-aided manufacturing systems. Examples with end-milling and side-milling tools are demonstrated and real cutting parts are implemented for verifying the algorithm.
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