Parallel-machine scheduling to minimize tardiness penalty and power cost

Traditional research on machine scheduling focuses on job allocation and sequencing to optimize certain objective functions that are defined in terms of job completion times. With regard to environmental concerns, energy consumption becomes another critical issue in high-performance systems. This paper addresses a scheduling problem in a multiple-machine system where the computing speeds of the machines are allowed to be adjusted during the course of execution. The CPU adjustment capability enables the flexibility for minimizing electricity cost from the energy saving aspect by sacrificing job completion times. The decision of the studied problem is to dispatch the jobs to the machines as well as to determine the job sequence and processing speed of each machine with the objective function comprising of the total weighted job tardiness and the power cost. We give a formal formulation, propose two heuristic algorithms, and develop a particle swarm optimization (PSO) algorithm to effectively tackle the problem. Since the existing solution representations do not befittingly encode the decisions involved in the studied problem into the PSO algorithm, we design a tailored encoding scheme which can embed all decisional information in a particle. A computational study is conducted to investigate the performances of the proposed heuristics and the PSO algorithm.     

On Topological Watersheds

In this paper, we investigate topological watersheds (Couprie and Bertrand, 1997). One of our main results is a necessary and sufficient condition for a map G to be a watershed of a map F, this condition is based on a notion of extension. A consequence of the theorem is that there exists a (greedy) polynomial time algorithm to decide whether a map G is a watershed of a map F or not. We introduce a notion of separation between two points of an image which leads to a second necessary and sufficient condition. We also show that, given an arbitrary total order on the minima of a map, it is possible to define a notion of degree of separation of a minimum relative to this order. This leads to a third necessary and sufficient condition for a map G to be a watershed of a map F. At last we derive, from our framework, a new definition for the dynamics of a minimum.Gilles Bertrand received his Ingénieurs degree from the École Centrale des Arts et Manufactures in 1976. Until 1983 he was with the Thomson-CSF company, where he designed image processing systems for aeronautical applications. He received his Ph.D. from the École Centrale in 1986. He is currently teaching and doing research with the Laboratoire Algorithmique et Architecture des Systémes Informatiques, ESIEE, Paris, and with the Institut Gaspard Monge, Université de Marne-la-Vallée. His research interests are image analysis, discrete topology and mathematical morphology.     

Design and implementation of software for assembly and browsing of 3D brain atlases

Visualization software for three dimensional digital brain atlases present many challenges in design and implementation. These challenges include the design of an effective human interface, management of large data sets, display speed when slicing the data set for viewing/browsing, and the display of delineated volumes of interest (VOI). We present a software design, implementation and storage architecture that addresses these issues, allowing the user to navigate through a reconstructed volume quickly and smoothly, with an easy-to-use human interface. The software (macostat, for use with Macintosh OS) allows the user to rapidly display slices of the digital atlas at any arbitrary slicing angle, complete with delineated VOIs. The VOIs can be assigned colors of the user's choosing. The entire atlas, or selected portions, may be resliced with slices stored as individual image files, complete with delineations. These delineations may be transferred to corresponding sections of experimental materials using our analysis program (brain). The software may be obtained from the laboratory's web site: http://www.neuroterrain.org     

Efficiency of Spectral-Based ADC Test Flows to Detect Static Errors

Testing of Analog-to-Digital Converters is classically composed of two successive and independent phases: the histogram-based test technique evaluating static specifications and the spectral analysis technique evaluating the dynamic performances. Consequently, the fundamental objective here is to investigate the feasibility of an alternative test flow involving exclusively spectral analysis to replace these two time consuming and expensive phases. The viability of this solution depends on the ability of spectral analysis to detect static specifications. In this context, this paper presents a new methodology based on a statistical approach to quantitatively evaluate the efficiency of detecting static errors from dynamic parameter measurements. This methodology has been implemented in an in-house automatic tool allowing one to process any ADC specifications. It is then possible to choose a priori the best test flow for a given application.     

An assessment of façade coatings against colonisation by aerial algae and cyanobacteria

An accelerated water-streaming test method was used to evaluate several types of façade coatings regarding their behaviour to colonisation by algae and cyanobacteria, by closely reproducing the phenomenon of natural biological soiling. A set of materials with defined physical characteristics was thus investigated vs. the colonisation by algal and cyanobacterial strains isolated from natural façade biofilms. Porosity and roughness of the materials showed to be factors of influence in the establishment of those micro-organisms.     

Speculative Behaviour in Immature Real Estate Markets, Lessons of the 1997 Asia Financial Crisis

This article investigates speculative behaviour and focuses on developer and banker behaviour in Asian real estate markets at the time of the 1997 Asia financial crisis. Over-optimism and over-investment are exacerbated when the financial infrastructure is incomplete and real estate markets are immature. The article identifies improvements in the real estate market infrastructure needed to lower the amplitude and cost of future episodes of volatility.     

Making Progress Towards « Green » Propellants – Part III

Stabilisers are an integral part of a propellant composition. They are essential for ensuring the chemical stability of nitrate-ester based propellants, preventing oxidation, chain scission and uncontrolled heat generation. Progress is being made, especially in Europe, with REACh legislation (1907/2006) to use more environmentally-friendly compounds. New stabilisers with a greener environmental profile and producing less toxic daughter products have been investigated by several groups, and several compounds demonstrated even better performances – more chemical stability and therefore longer shelf lives than formulations with the currently-used stabilisers. Additionally, the good efficiencies and lower toxicities of the daughter products of the “green” stabilisers are also evaluated. This paper is a continuation of our previous work and demonstrates that for industrially-manufactured propellants, that the tests performed by four different entities validate the stability and compatibility of the propellants, investigated previously on a laboratory scale, providing the community with safer formulations for the environment and health.