Effectiveness of early replies in clientserver systems.docx

1、Effectiveness of early replies in clientserver systemsA client-based logging technique using backward analysis of log in client/server environmentOriginal Research ArticleJournal of Systems and Softwarepractical computing algorithm working in real time has been developed for calculations of the refl

2、ection high-energy electron diffraction from the molecular beam epitaxy growing surface. The calculations are based on a dynamical diffraction theory in which the electrons are scattered on a potential, which is periodic in the direction perpendicular to the surface. New version program summaryTitle

3、 of program:RHEED_v2 Catalogue identifier:ADUY_v1_1 Program summary URL: http:/cpc.cs.qub.ac.uk/summaries/ADUY_v1_1 Program obtainable from: CPC Program Library, Queens University of Belfast, N. Ireland Catalogue identifier of previous version:ADUY Authors of the original program:A. Daniluk Does the

4、 new version supersede the original program:Yes Computer for which the new version is designed and others on which it has been tested: Pentium-based PC Operating systems or monitors under which the new version has been tested: Windows 9x, XP, NT, Linux Programming language used:C+ Memory required to

5、 execute with typical data:more than 1 MB Number of bits in a word:64 bits Number of processors used:1 Number of bytes in distributed program, including test data, etc.:1074131 No. of lines in distributed program, including test data, etc.:3408 Distribution format:tar.gz Nature of physical problem:

6、Reflection high-energy electron diffraction (RHEED) is a very useful technique for studying the growth and the surface analysis of thin epitaxial structures prepared by the molecular beam epitaxy (MBE). RHEED rocking curves recorded from heteroepitaxial layers are used for the non-destructive evalua

7、tion of epilayer thickness and composition with a high degree of accuracy. Rocking curves from such heterostructures are often very complex because the thickness fringes from every layer beat together. Simulations based on dynamical diffraction theory are generally used to interpret the rocking curv

8、es of such structures from which very small changes in thickness and composition can be obtained. Rocking curves are also used to determine the level of strain and its relaxation mechanism in a lattice-mismatched system. Method of solution: The new version of the program retains the design and struc

9、ture of the previous one A. Daniluk, Comput. Phys. Comm. 166 (2005) 123. 1. Reasons for the new version: Responding to the user feedback we presented an extension of the RHEED program that enables computing the crystalline potentials for epitaxial heterostructures and corresponding values of the amp

10、litude of the RHEED intensity oscillations. Summary of revisions: (1) In this paper we show how the dynamical approach may be applied to creation of a practical computing algorithm to calculate of the intensity of the specularly reflected RHEED beam during MBE growth of Pb on Si(111). The structural

11、 properties of the PbSi interface have beenFig. 1.Contracted division of the substrate and surface layers into an assembly of n atomic layers and i thin slices parallel to the surface.bFig. 2.One-dimensional (z-direction) potential of Pb/Si(111) at 70 K.Fig. 3.Computer simulated one-beam rocking cur

12、ve for some Pb layers on a Si(111) substrate.meticulously studied by Howes and co-workers P.B. Howes, K.A. Edwards, D.J. Hughes, J.E. Macdonald, T. Hibma, T. Bootsma, M.A. James, Surf. Sci. Lett. 331 (1995) 646; K.A. Edwards, P.B. Howes, J.E. Macdonald, T. Hibma, T. Bootsma, M.A. James, Surf. Sci. 4

13、24 (1999) 169. 2 and 3, and Lucas and Loretto C.A. Lucas, D. Loretto, Surf. Sci. Lett. 344 (1995) 1219. 4 (X-ray diffraction). The new version of the RHEED program has the same design as the previous one A. Daniluk, Comput. Phys. Comm. 166 (2005) 123. 1. To simulate the structural variations of whol

14、e crystalline heterostructure along the surface normal direction the substrate and layers are divided into an assembly of n atomic layers. Each of these layers is further divided into an assembly of i thin slices parallel to the surface and each slice is assumed to have a constant potential normal t

15、o the surface as shown in Fig. 1. The Fourier component of the scattering potential of the whole crystalline heterostructure can be determined as a sum of contributions coming from all thin slices of n individual atomic layers. To carry out one-dimensional calculations we used the self-consistent th

16、icknessZi_Substrate(), thicknessZi_Layers(), thicknessZn_Substrate(), thicknessZn_Layers(), crystPotUgSubstrate() and crystPotUgLayers() functions. Fig. 2 presents the crystalline potentials (real part) calculated for some Pb layers on a Si(111) substrate at 70 K. Fig. 3 shows a dynamically calculat

17、ed one-beam rocking curve for Pb/Si(111).Fig. 4.The numberOfLayers and NLayers constant parameters should be initiated to 0 during calculations carrying out for monocrystalline substrate.Fig. 5.The thicknessZi_Layers(), thicknessZn_Layers() and crystPotUgLayers() functions are not used during calcul

18、ations for monocrystalline substrate.(2) The presented algorithm is a generalization of the previous one. By attributing 0 to the numberOfLayers and NLayers constant parameters (Fig. 4) and removing appropriate functions from the main program (Fig. 5), we obtain the same results as in the case of mo

19、nocrystal A. Daniluk, Comput. Phys. Comm. 166 (2005) 123. 1. Typical running time: The typical running time is machine and user-parameters dependent. Unusual features of the program: The program is presented in the form of a basic unit RHEED_v2.cpp. It is not tied to any specific hardware and system

20、s software platform, and could be compiled using C+ compilers, including C+ Builder, VC+ and g+.Web-enabled configuration and control of legacy codes: An application to ocean modelingOriginal Research ArticleOcean ModellingAn adaptive neural network strategy for improving the computational performan

21、ce of evolutionary structural optimizationOriginal Research ArticleComputer Methods in Applied Mechanics and EngineeringThe main part of the code presented in this work represents an implementation of the split-operator method J.A. Fleck, J.R. Morris, M.D. Feit, Appl. Phys. 10 (1976) 129160; R. Heat

22、her, Comput. Phys. Comm. 63 (1991) 446 for calculating the time-evolution of Dirac wave functions. It allows to study the dynamics of electronic Dirac wave packets under the influence of any number of laser pulses and its interaction with any number of charged ion potentials. The initial wave functi

23、on can be either a free Gaussian wave packet or an arbitrary discretized spinor function that is loaded from a file provided by the user. The latter option includes Dirac bound state wave functions. The code itself contains the necessary tools for constructing such wave functions for a single-electr

24、on ion. With the help of self-adaptive numerical grids, we are able to study the electron dynamics for various problems in 2+1 dimensions at high spatial and temporal resolutions that are otherwise unachievable. Along with the position and momentum space probability density distributions, various ph

25、ysical observables, such as the expectation values of position and momentum, can be recorded in a time-dependent way. The electromagnetic spectrum that is emitted by the evolving particle can also be calculated with this code. Finally, for planning and comparison purposes, both the time-evolution an

26、d the emission spectrum can also be treated in an entirely classical relativistic way. Besides the implementation of the above-mentioned algorithms, the program also contains a large C+ class library to model the geometric algebra representation of spinors that we use for representing the Dirac wave

27、 function. This is why the code is called “Dirac+”. Currently, there is a plethora of low-cost commercial off-the-shelf (COTS) hardware available for implementing control systems. These range from devices with fairly low intelligence, e.g. smart sensors and actuators, to dedicated controllers such a

28、s PowerPC, programmable logic controllers (PLCs) and PC-based boards to dedicated systems-on-a-chip (SoC) ASICS and FPGAs. When considering the construction of complex distributed systems, e.g. for a ship, aircraft, car, train, process plant, the ability to rapidly integrate a variety of devices fro

29、m different manufacturers is essential. A problem, however, is that manufacturers prefer to supply proprietary tools for programming their products. As a consequence of this lack of openness, rapid prototyping and development of distributed systems is extremely difficult and costly for a systems int

30、egrator. Great opportunities thus exist to produce high-performance, dependable distributed systems. However, the key element that is missing is software tool support for systems integration. The objective of the Flexible Control Systems Development and Integration Environment for Control Systems (F

31、LEXICON) project IST-2001-37269 is to solve these problems for industry and reduce development and implementation costs for distributed control systems by providing an integrated suite of tools to support all the development life-cycle of the system. Work within the Rolls-Royce supported University

32、Technology Centre (UTC) is investigating rapid prototyping of controllers for aero-engines, unmanned aerial vehicles and ships. This paper describes the use of the developed co-simulation environment for a high-speed merchant vessel propulsion system application.Article Outline1. Introduction2. FLEXICON toolset3. Co-simulation environment based on CORBA 3.1. CORBA approach4. Marine application5. Co-simulation for the marine application 5.1. Captains interface5.2. Co-simulation interfaceISaGRAF and Simulink 5.2.1. Prop