Hybrids of meta-heuristics have been shown to be more effective and adaptable than their parents in solving combinatorial optimization problems. However, hybridized schemes are also more tedious to implement due to their increased complexity. We address this problem by proposing the meta-heuristics development framework (MDF). In addition to being a framework that promotes software reuse to reduce developmental effort, the key strength of MDF lies in its ability to model meta-heuristics using a “request, sense and response” schema, which decomposes algorithms into a set of well-defined modules that can be flexibly assembled through a centralized controller. Under this scheme, hybrid schemes become an event-based search that can adaptively trigger a desired parent's behavior in response to search events. MDF can hence be used to design and implement a wide spectrum of hybrids with varying degrees of collaboration, thereby offering algorithm designers quick turnaround in designing and testing their meta-heuristics. Such technicality is illustrated in the paper through the construction of hybrid schemes using ant colony optimization and tabu search. [ABSTRACT FROM AUTHOR]
Singhal, S.K., Jain, Prashant K., Pandey, Pulak M., and Nagpal, A.K.
International Journal of Production Research. Nov2009, Vol. 47 Issue 22, p6375-6396. 22p. 1 Color Photograph, 4 Diagrams, 2 Charts, 6 Graphs.
ALGORITHMS, INDUSTRIAL efficiency, PROBLEM solving, PRODUCTION (Economic theory), SURFACE roughness, and SINTERING
In the present work an attempt has been made to achieve minimum average part surface roughness (best overall surface quality), minimum build time and support structure for stereolithography (SL) and selective laser sintering (SLS) processed parts by determining optimum part deposition orientation. A conventional optimisation algorithm based on a trust region method (available with MATLAB-7 optimisation tool box) has been used to solve the multi-objective optimisation problem. It is observed that the problem is highly multi-modal in nature and a suitable initial guess, which is used as an input to execute the optimisation module, is important to achieve a global optimum. A simple methodology has been proposed to find out the initial guess so that global minimum is obtained. Finally the surface roughness simulation is carried out with optimum part deposition orientation to have an idea of surface roughness variation over the entire part's surface before depositing the part. Case studies are presented to demonstrate the capabilities of the developed system. The major achievements of this work are consideration of multiple objectives for the two rapid prototyping processes, successful use of conventional optimisation algorithm available with MATLAB to handle multiple objectives and development of graphical user interface-based system. [ABSTRACT FROM AUTHOR]
A rapid prototyping (RP) machine system which combines a PC-based controller with the thermal-extrusion method is presented. The proposed RP system offers a three-axis platform, an extrusion head, a temperature controller, and a PC-based control system. Low-cost acrylonitrile-butadiene-styrene (ABS) pellets/powder are used for thermal extrusion, although the system is easily adapted to other not-too-dissimilar materials. In order to improve the quality of RP part, the Taguchi method was used to analyzing the process parameters of the pro- posed RP system. Based on the experimental results, the proposed RP mechatronics system can produce good quality RP parts. The RP software technique includes slicing, support, tool path, and motion code generation. This paper also presents a new adaptive slicing algorithm for RI' system. According to this algorithm, the three-dimensional (3-D) computer-aided design (CAD) model can be sliced with different thickness automatically by comparing the contour circumference or the center of gravity of the contour with those of the adjacent layer. With this adaptive slicing method, the part can be fabricated faster than it uses uniform slicing method with identical accuracy. Finally, the intelligent web-based RP system allows remote users to upload an STL file, to directly building up of the physical model, and to monitor the actual fabrication process from a charged coupled devices (C CD) camera located in the RP machine itself. The user does not need to buy an expensive RP machine; instead, he can rent time and uses the machine remotely via the Internet. [ABSTRACT FROM AUTHOR]
Jacobs, Joep, Detjen, Dirk, Karipidis, Claus-Ulrich, and de Doncker, Rik W.
IEEE Transactions on Power Electronics. Mar2004, Vol. 19 Issue 2, p500-507. 8p.
RAPID prototyping, ALGORITHMS, DIGITAL signal processing, POWER electronics, CASCADE converters, and ELECTRIC circuits
This paper presents three new rapid prototyping took to develop power electronic systems. The effectiveness of these tools is demonstrated by designing and building a shunt active power filter. First, a digital signal processor (DSP) model to embed complex control algorithms has been created for detailed offline simulations with PSpice. This DSP model emulates the discrete behavior of digital control circuits. The control algorithms in the DSP model ace implemented In C-code. Secondly, the control C-code can be downloaded to the !SEADSP for real-time execution. The LSEADSP is a universal DSP control board based on two 80 SHARC processors which execute control algorithms of various nature and highest complexity at 80 MFLOP per second. Thirdly, power electronic building blocks (PEBBs) based on IGBT devices were developed to build and analyze quickly different converter topologies. Combining these three rapid prototyping tools led to a significant reduction of development time of power electronic applications. [ABSTRACT FROM AUTHOR]
ALGORITHMS, MANUFACTURES, ENGINEERING, MANUFACTURING processes, NEW product development, BIOMEDICAL engineering, COMPUTER simulation, and VIRTUAL reality
This paper proposes a multi-material virtual prototyping (MMVP) system that integrates the virtual reality (VR) and the layered manufacturing (LM) technologies for digital fabrication of heterogeneous multi-material prototypes for advanced product development and biomedical engineering. The system consists mainly of two algorithms for sequential and concurrent multi-toolpath planning, and a virtual prototyping system. The algorithms adopt a topological hierarchy-sorting algorithm to establish the hierarchy relationship of multi-material slice contours for facilitating toolpath planning of multi-material layered manufacturing (MMLM). Subsequently, the sequential multi-toolpath planning algorithm generates sequential toolpaths that avoid redundant tool movements. To reduce build time further, the concurrent multi-toolpath planning algorithm generates collision-free concurrent toolpaths. Based on the hierarchy information, a bounding box can be adopted to approximate envelopes of contour families of the same material property to simplify detection of tool collisions. The algorithms are integrated to form the MMVP system for planning, stereoscopic simulation, and validation of multi-toolpaths for MMLM. [ABSTRACT FROM AUTHOR]
ALGORITHMS, RAPID prototyping, MANUFACTURING processes, SOFTWARE libraries (Computer programming), and COMPUTER software development
Quadrilateral meshes are ubiquitously used as a control grid for subdivision and parametric surfaces. The process of converting a triangular mesh into a quadrilateral is called retopology, or quadrilateral meshing, and it is an essential step for the creation of 3D models used in games, movies, and special effects. This article introduces the problem, highlights the major differences between triangular and quadrilateral meshes, and provides an overview of several new automatic and semiautomatic solutions. The pros and cons of each algorithm are discussed as well as interesting directions for future work in this area. [ABSTRACT FROM AUTHOR]
IEEE Transactions on Computer-Aided Design of Integrated Circuits & Systems. 04/01/2011, Vol. 30 Issue 4, p473-491. 19p.
PROTOTYPES, ALGORITHMS, INDUSTRIAL design, FIELD programmable gate arrays -- Design & construction, SYSTEMS on a chip, CASE studies, and EXPERIMENTS
Escalating system-on-chip design complexity is pushing the design community to raise the level of abstraction beyond register transfer level. Despite the unsuccessful adoptions of early generations of commercial high-level synthesis (HLS) systems, we believe that the tipping point for transitioning to HLS methodology is happening now, especially for field-programmable gate array (FPGA) designs. The latest generation of HLS tools has made significant progress in providing wide language coverage and robust compilation technology, platform-based modeling, advancement in core HLS algorithms, and a domain-specific approach. In this paper, we use AutoESL's AutoPilot HLS tool coupled with domain-specific system-level implementation platforms developed by Xilinx as an example to demonstrate the effectiveness of state-of-art C-to-FPGA synthesis solutions targeting multiple application domains. Complex industrial designs targeting Xilinx FPGAs are also presented as case studies, including comparison of HLS solutions versus optimized manual designs. In particular, the experiment on a sphere decoder shows that the HLS solution can achieve an 11–31% reduction in FPGA resource usage with improved design productivity compared to hand-coded design. [ABSTRACT FROM AUTHOR]
IEEE Transactions on Geoscience & Remote Sensing. Sep2000 Part 2 of 2, Vol. 38 Issue 5, p2402. 17p. 1 Diagram, 6 Charts, 10 Graphs.
ALGORITHMS, SPECTRORADIOMETER, and REFLECTANCE
Presents a study which described the prototyping of multi-angle imaging spectroradiometer (MISR), leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) algorithm with the polarization and directionality of the Earth's reflectance date over Africa. Advantages of using multi-angle data over single-data of surface reflectance; Mathematical basis for multi-angle remote sensing of vegetation; Results of prototyping.
Journal of Systems & Software. Mar99, Vol. 45 Issue 2, p141. 14p. 1 Black and White Photograph, 10 Diagrams.
ENGINEERING design, DISTRIBUTED computing, and ALGORITHMS
Focuses on a study that examined the design and implementation of a rapid prototyping system for distributed algorithms. Key to rapid prototyping; Object oriented design of IPC...F Base software; Implementation of rapid prototyping system on a transputer network; Experience of using the prototyping systems to rapidly build prototypes; Layered structure of IPC subsystem functions.
Liu, F., Tan, Q., Chen, G., Song, X., Ait Mohamed, O., and Gu, M.
IET Computers & Digital Techniques. Jul2010, Vol. 4 Issue 4, p306-316. 11p. 9 Diagrams, 4 Graphs.
ALGORITHMS, FIELD programmable gate arrays, PROGRAMMABLE logic devices, GATE array circuits, and MICROPROCESSORS
As an important part of many processors's floating point unit, fused multiply-add unit performs a multiplication followed immediately by an addition. In IBM POWER6 microprocessor's fused multiply-add unit, a fast 128-bit floating-point end-around-carry (EAC) adder is proposed. Very few algorithmic details exist in today's literature about this adder. In this study, a complete designed EAC adder that can work independently as a regular adder is proposed. Details about the proposed EAC adder's arithmetic algorithms are described. In IBM's original EAC adder, the Kogge–Stone tree has been chosen for its high performance on ASIC technology. In this study, the authors present a comparative study on different parallel prefix trees which are used in the design of our new EAC adder targeting field programmable gate array (FPGA) technology. Our study highlights the main performance differences among 14 different architecture configurations focusing on the area requirements and the critical path delay. The experimental results show that there is one architecture configuration with the lower area requirement and the higher performance. [ABSTRACT FROM AUTHOR]
In this paper, detailed algorithms are presented for eliminating inconsistency in a tri-dexel volumetric models and reconstructing a water-tight polyhedral surface model from the tri-dexel volumetric model. By using the surface normal information saved in each dexel grid node, a refinement process is applied to reconstructing sharp edges and apex vertices in polyhedral surface models. The advantage of tri-dexel model is its balance in modeling accuracy and memory consumption. It is a challenge problem to convert it to a water-tight polyhedral surface model for downstream applications. The proposed techniques can be used as a geometric representation kernel in Computer-Aided Design and Manufacturing (CAD/CAM) and Computer Numerically-Controlled process simulation systems. [ABSTRACT FROM AUTHOR]
IEEE Transactions on Geoscience & Remote Sensing. Sep2000 Part 2 of 2, Vol. 38 Issue 5, p2387. 15p. 1 Diagram, 3 Charts, 9 Graphs.
ALGORITHMS, LANDSAT satellites, and VEGETATION & climate
Presents a study which described the concepts of the algorithm of global leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR). Effects of vegetation misclassification on LAI/FPAR retrievals; Analysis on the spectral signatures of land surface reflectances and Landsat data; Importance of vegetation in studies of global climate and biogeochemical cycles.