5,835 research outputs found
OBJECT-ORIENTED AND FUNCTIONAL SOFTWARE-DESIGN FOR DISTRIBUTED REAL-TIME SYSTEMS
No full textReal-time systems in applications like command, control, communications and intelligence require complex distributed systems with many interacting software components, heterogeneous processing systems and sharing resources. These systems should satisfy not only the functional requirements of application software, but also the specified timing constraints on the execution of the software, despite faults and failures. In addition, parallelism needs to be expressed in the design of such systems and exploited on the target distributed computing systems. In this paper, an approach to software design for distributed real-time computing systems, based on the PROOF computation model which integrates object-oriented and functional paradigms, is presented. To support adaptability of the software system to a predictably changing environment, our approach supports multi-versions of a method definition, synchronous communication within objects, asynchronous communication among objects, encapsulation of timing constraints in objects and expressing parallelism in object-level and method-level. Our design approach consists of the high-level object-oriented design and object design phases. Our design approach is illustrated with a hypothetical chemical plant simulation system
Deposition of fluorinated amorphous carbon thin films with low dielectric constant and thermal stability
No full text
SOFTWARE-DESIGN METHODS FOR DISTRIBUTED COMPUTING SYSTEMS
No full textDue to the rapid development of computer, communication and microelectronics technologies, the trend of distributed computing systems is to become more distributed. Because the characteristics of distributed computing systems are significantly different from those of traditional computing systems, different approaches are needed to effectively address the design issues related to the characteristics of software for distributed computing systems. In this paper, the methods currently used to develop the software for distributed computing systems are classified into three approaches: dataflow-oriented; communication-oriented; and object-oriented. Their applicabilities to various applications for distributed computing systems are discussed, and object-oriented approach is identified as a more promising approach to developing distributed software. The future trends and research directions of software development techniques for distributed computing systems are discussed
OBJECT-ORIENTED DEVELOPMENT OF ARCHITECTURE TRANSPARENT SOFTWARE FOR DISTRIBUTED PARALLEL SYSTEMS
No full textCompared with programming sequential computers, programming distributed parallel computing systems has additional complexity due to the considerations of parallelism, synchronization, the network configuration of the distributed computing system, and the topology of the parallel processors. Current programming practices, however, are not sufficient to make effective use of such computing systems. In this paper, an approach to software development for distributed parallel processing systems which is architecture transparent is presented. This approach is based on the object-oriented concept, and facilitates the design and coding of software by separating the architecture-dependent issues from the semantics of the software. This makes the software system independent of the target machine or the network configuration. and easily portable to other machines. In our approach, the parallelism is implicit in the program, and the programmer does not need to be concerned with issues such as synchronization, network configuration or the topology of the parallel processors. Our approach can reduce the communication and synchronization errors caused by the programmer by automatically embedding the proper codes during the translation and allocation phases of the software development cycle
RDLS-SS-DWT v. 0.9
No full textThis fileset contains the implementation of RDLS-DWT and SS-DWT in JPEG 2000 (RDLS-SS-DWT v. 0.9), which was used in a research described in: R. Starosolski, “Application of reversible denoising and lifting steps to DWT in lossless JPEG 2000 for improved bitrates,” Signal Processing: Image Communication, Vol. 39, Part A, pp. 249-63, DOI: 10.1016/j.image.2015.09.013, 2015 and R. Starosolski, “Skipping selected steps of DWT computation in lossless JPEG 2000 for improved bitrates,” submitted. This software is intended for research purposes only; it is provided "as is"; author makes no warranty of any kind, either express or implied, with respect to this software. <br
Influence of sludge retention time on membrane fouling and bioactivities in membrane bioreactor system
No full textSludge retention time (SRT) can produce significant effects on biomass properties in a membrane bioreactor (MBR) system. In this study, the membrane separation process was coupled to a sequencing batch reactor (SBR), which is one of the biological nutrient removal (BNR) processes, and the influence of SRT on membrane fouling and biological activity was investigated. Membrane fouling increased with SRT since sludge particles were more severely deposited on the membrane surface at longer SRT. Regardless of SRT change, COD removal efficiency was high and stable (over 92%) throughout the experiment. Nitrogen removal efficiency also attained a high treatment level. However, it was not proportioned to SRT increase and rather decreased at the longest SRT. Phosphorus removal decreased at prolonged SRT since excess sludge was reduced. Biological activity such as specific oxygen uptake rate (SOUR), specific nitrification rate (SNR), and specific denitrification rate (SDNR) did not increase with SRT but decreased at prolonged SRT. (c) 2004 Elsevier Ltd. All rights reserved.
Preparation of a-SiNx thin film with low hydrogen content by inductively coupled plasma enhanced chemical vapor deposition
No full textAmorphous silicon nitride (a-SiNx) thin films are deposited at low temperature by remote-type inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) using N-2/SiH4 gases as reactant gases to obtain low hydrogen content in the films. Refractive index, deposition rate, stoichiometry, hydrogen content, and hydrogen configuration in the films are analyzed with the varation of deposition parameters. As RF power and N-2 flow rate increase, refractive index decreases due to the decrease of Si/N ratio, total hydrogen content is constant with N-H changing hydrogen bond configurations (Si-H, N-H) reversely. However, as substrate temperature increases, refractive index increases due to the reduction of Si/N ratio, and total hydrogen content as well as both hydrogen bond configurations (Si-PI, N-H) decrease. In remote-type ICP-CVD using N-2/SiH4 gases, N rich a-SiNx films with low refractive index and density are deposited due to efficient dissociation of N-2 gas by high density plasma, and hydrogen content in the films is greatly reduced.This work was supported by Ministry of Education through Interuniversity Semiconductor Research Center(ISRC 96-E-4021)in Seoul National University.
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Spectroscopic ellipsometry and Raman study of fluorinated nanocrystalline carbon thin films
No full textUsing spectroscopic ellipsometry and Raman spectroscopy, we measured the pseudodielectric function and the phonon frequencies of fluorinated nanocrystalline carbon (nc-C:F) thin films grown on silicon substrate at varying growth temperature and gas flux ratio of CH4 and CF4. Utilizing the Tauc-Lorentzian formula, we performed multilayer analysis to estimate the dielectric function of the fluorinated nanocrystalline carbon thin films. We also adopted Gaussian-like density-of-states model proposed by Demichelis [Phys. Rev. B 45, 14364 (1992)] and estimated the amplitude A, the transition energy E-pi, and the broadening sigma (pi) of pi --> pi* transitions. Based on this model, we explained the change of the optical gap and the refractive index in terms of the change of the amplitude A rather than the shift of transition energy E-pi of pi --> pi* transitions. Raman and ellipsometric study suggested that the average size of nanocrystallites in the fluorinated carbon thin films was smaller than that of amorphous hydrogenated carbon films studied by Hong [Thin Solid Films 352, 41 (1999)]. (C) 2001 American Institute of Physics
- …
