Automatic Virtual Entity Simulation of Conceptual Design Results Part I： Symbolic Scheme Generation and Identification

The development of new products of high quality, low unit cost, and short lead time to market are the key elements required for any enterprise to obtain a competitive advantage. For shorting the lead time to market and improving the creativity and performances of the product, a rule-based conceptual design approach and a methodology to simulate the conceptual design results generated in conceptual design process in automatical virtual entity form are presented in this paper. This part of paper presents a rule-based conceptual design method for generating creative conceptual design schemes of mechanisms based on Yan＇s kinematic chain regeneration creative design method. The design rules are adopted to describe the design requirements of the functional characteristics, the connection relationships and topological characteristics among mechanisms. Through the graphs-based reasoning process, the conceptual design space is expanded extremely, and the potential creative conceptual design results are then dug out. By refining the design rules, the solution exploration problem is avioded, and the tendentious conceptual design schemes are generated. Since mechanical, electrical and hydraulic subsystems can be transformed into general mechansims, the conceptual design method presented in this paper can also be applied in the conceptual design problem of complex mechatronic systems. And then the method to identify conceptual design schemes is given.     

Automatic Virtual Entity Simulation of Conceptual Design Results—Part Ⅱ:Symbolic Scheme Simulation

The development of new products of high quality, low unit cost, and short lead time to market are the key elements required for any enterprise to obtain a competitive advantage. This part of the paper presents a methodology to automatically simulate the conceptual design results in the virtual entity form. To the identified basic mechanisms, their kinematic analysis is carried out by matching basic Barranov trusses, and their virtual entities are modeled based on feature-based technique and encapsulated as one design object. Based on the structures of the basic mechanisms and their connections, a space layout to the mechanical system corresponding to the symbolic scheme is then fulfilled. With the preset-assembly approach, all parts in the mechanical system are put onto proper positions where the constraint equations are met according to the space layout results. In this way, the virtual entity assembly model of the mechanical system relative to the symbolic scheme is set up. The approach presented in this paper can not only obtain innovative conceptual conceptual design results, but also can evaluate their performances under 3-D enviroment efficently.     

The Identification of Spelling Variants in English and German Historical Texts: Manual or Automatic?

In this article, we describe the respective approaches we havetaken when addressing issues of spelling variation in Germanand English historical texts. More specifically, we describean experiment to evaluate automatic techniques for the developmentof letter replacement heuristics against manually created goldstandards of known letter replacements rules. As will becomeclear, the motivation for the research differs according tothe team of researchers: the German researchers are seekingto develop a search engine for historical texts; the Englishresearchers want to improve the results obtained when applyingcorpus linguistic techniques (developed for modern language)to historical data. However, the respective teams do share alonger term goal of assessing whether it is possible to developa generic spelling detection tool for Indo-European languages.     

On Simulation and Design of Parallel-Systems Schedulers: Are We Doing the Right Thing?

It is customary to use open-system trace-driven simulations to evaluate the performance of parallel-system schedulers. As a consequence, all schedulers have evolved to optimize the packing of jobs in the schedule, as a means to improve a number of performance metrics that are conjectured to be correlated with user satisfaction, with the premise that this will result in a higher productivity in reality. We argue that these simulations suffer from severe limitations that lead to suboptimal scheduler designs and to even dismissing potentially good design alternatives. We propose an alternative simulation methodology called site-level simulation, in which the workload for the evaluation is generated dynamically by user models that interact with the system. We present a novel scheduler called CREASY that exploits knowledge on user behavior to directly improve user satisfaction and compare its performance to the original packing-based EASY scheduler. We show that user productivity improves by up to 50 percent under the user-aware design, while according to the conventional metrics, performance may actually degrade.     

Exact optimal grillage layouts — Part I: Combinations of free and simply supported edges

In the first instalment of this three-part study, a comprehensive treatment of analytically derived, exact optimal grillage layouts for combinations of simply supported and free edges is given. In part two, grillages with combinations of simply supported, clamped and free edges will be considered.Notation k constant in specific cost function - M beam bending moment - r radius of circular edge - R ⁺,R ^–,S ⁺,S ^–,T optimal regions - x, x _j coordinate along a beam (j) - slope of the adjoint deflection at pointD in directionDA - t, v coordinates along the free edge - adjoint deflection - angle between long beams and free edge - angle between free and simply supported edges - curvature of the adjoint deflection - , angles for layouts with circular edge - total weight (cost) of grillage - coordinate along a beam in anR ⁺ region - distance defined in Fig. 3     

The power of computational thermochemistry in high-temperature process design and optimization: Part 1 — Unit operations

Industrial process modeling is increasingly accessible through computational chemistry packages. Computational Thermochemistry (CT) is particularly convenient for exploring the behavior of high-temperature processes (e.g., pyrometallurgical unit operations such as calciners, roasters, smelters, converters, and electric arc furnaces) since their operating conditions are mostly dictated by local/global thermodynamic phase equilibria. Under these high-temperature conditions, energy barriers are small and do not limit the kinetics of many chemical reactions. In this context, engineers-in-training must take full advantage of CT to explore and understand current unit operations in high-temperature manufacturing technologies. This work illustrates the strength of computational thermochemistry for high-temperature modeling through four case studies, i.e., 1. a carbo-reduction process, 2. a glass production/recycling furnace, 3. an aluminothermic reactor for the production of a ferroniobium alloy, and 4. a titanium purification unit. Moreover, the relevance of key fundamental thermodynamic concepts is discussed through the modeling of these unit operations. All the thermodynamic simulations presented in this work were performed using FactSage, a metallurgy-specialized thermochemical package widely employed in both academia and industry.     

Input–output feedback linearizing control of linear induction motor taking into consideration the end-effects. Part II: Simulation and experimental results

This is the second part of a paper, divided in two parts, dealing with the application of the input–output feedback linearization (FL) control technique to linear induction motors (LIMs).The first part has treated the theoretical formulation of the input–output feedback linearization control technique as to be applied to linear induction motors. This second part describes the set of tests, both in numerical simulations and experiments, performed to assess the validity of the control technique. In particular, it addresses the issues of the sensitivity of the FL control versus the LIM electrical parameters’ variations and the improvements achievable by considering the LIM dynamic end effects in the control formulation.The proposed FL technique has been further compared, under the same closed-loop bandwidths of the flux and speed systems, with the industrial standard in terms of high performance control technique: field oriented control (FOC).     

Identification of the transition state for fast reactions: The trapping of hydroxyl and methyl radicals by DMPO—A DFT approach

Up to date, attempts to locate the transition state (TS) for the trapping reaction between OH and DMPO have been unsuccessful, and the lack of molecular mechanisms by which OH binds to the spin-trap constitutes a question still unsolved. Herein, we have taken a step forward on this task by describing the theoretical TS for the trapping of OH and CH₃ by DMPO and the intrinsic reaction coordinates. This work aims to provide new understandings on the molecular orbital (MO) interactions that rule these reaction paths. Besides we assessed the degree of involvement of weak interactions and the charge transfer (CT) phenomenon involved in such interactions. Regarding the trapping of OH, the beginning of the reaction would be ruled by weak interactions to then give way to stronger MO interactions conducive to the formation of the TS. For CH₃, the reaction is, instead, early ruled by significant MO interactions, and a relatively small contribution in the weak interactions range. At the TS, both reactions share the formation of an antibonding orbital responsible for hosting the unpaired electron, and two bonding orbitals between the radical and the spin-trap. Additionally, the charge is transferred primarily from DMPO to OH through β orbitals, while for CH₃, the CT occurs in both directions, so that while DMPO behaves like an α-acceptor/β-donor, CH₃ acts as a β-acceptor/α-donor. Finally, we provide evidence showing that the resultant theoretical models are in agreement with the hyperfine coupling constants as obtained from biological-ESR spin trapping experiments.     

Study of the Radio Frequency (RF) performance of a Wafer-Level Package (WLP) with Through Silicon Vias (TSVs) for the integration of RF-MEMS and micromachined waveguides in the context of 5G and Internet of Things (IoT) applications: Part 1—validation of the 3D modelling approach

Microsystem Technologies - Packaging of Radio Frequency MicroElectroMechanical-Systems (RF-MEMS) and other passive components is a delicate issue, especially in the riverbed of upcoming application...     

A review of: “System Identification—Parameter and State Estimation.” By PIETER EYKHOFF. (Bristol : John Wiley & Sons, 1974.) [Pp. 555.] Price £12.50.

This article extends the concept of input–output finite time stability (IO–FTS) to a class of hybrid systems, namely impulsive dynamical linear systems, which are systems that exhibit jumps in the state trajectory. Sufficient conditions are given for the analysis of IO–FTS and for the design of both static output and state feedback controllers, guaranteeing IO–FTS of the closed loop system. In the general case the presented results require to solve feasibility problems involving either linear matrix inequalities or bilinear matrix inequalities, which can be solved numerically in an efficient way by using off-the-shelf optimisation tools, as illustrated by the proposed examples.