Practical implementation of possibilistic probability mass functions

 Probability assessments of events are often linguistic in nature. We model them by means of possibilistic probabilities (a version of Zadeh's fuzzy probabilities with a behavioural interpretation) with a suitable shape for practical implementation (on a computer). Employing the tools of interval analysis and the theory of imprecise probabilities we argue that the verification of coherence for these possibilistic probabilities, the corrections of non-coherent to coherent possibilistic probabilities and their extension to other events and gambles can be performed by finite and exact algorithms. The model can furthermore be transformed into an imprecise first-order model, useful for decision making and statistical inference.     

Scheduling and Lot Streaming in Flowshops with No-Wait in Process

Lot streaming involves splitting a production lot into a number of sublots, in order to allow the overlapping of successive operations, in multi-machine manufacturing systems. In no-wait flowshop scheduling, sublots are necessarily consistent, that is, they remain the same over all machines. The benefits of lot streaming include reductions in lead times and work-in-process, and increases in machine utilization rates. We study the problem of minimizing the makespan in no-wait flowshops producing multiple products with attached setup times, using lot streaming. Our study of the single product problem resolves an open question from the lot streaming literature. The intractable multiple product problem requires finding the optimal number of sublots, sublot sizes, and a product sequence for each machine. We develop a dynamic programming algorithm to generate all the nondominated schedule profiles for each product that are required to formulate the flowshop problem as a generalized traveling salesman problem. This problem is equivalent to a classical traveling salesman problem with a pseudopolynomial number of cities. We develop and computationally test an efficient heuristic for this problem. Our results indicate that solutions can quickly be found for flowshops with up to 10 machines and 50 products. Moreover, the solutions found by our heuristic provide a substantial improvement over previously published results.     

Modeling Fully Depleted SOI MOSFETs in 3D Using Recursive Scattering Matrices

As the semiconductor industry pushes towards ever decreasing device sizes, the need for an efficient yet accurate simulation method increases. We present a different approach to modeling ultra small semiconductor devices through the use of recursive scattering matrices. This approach is a completely quantum mechanical approach in three dimensions, yet does not suffer from excessive computation time or resources. While the transport in most small semiconductor devices is typically 2D in nature, with a 3D model we are capable of incorporating the interaction of the 3D modes in the contacts with the 2D modes in the active regions. We demonstrate this approach by presenting results for a short channel fully-depleted SOI (Silicon On Insulator) MOSFET. We present results using both hardwall potentials and self-consistent potentials as calculated through the use of an iterative Poisson solver.     

Integrating CAD tools for MEMS design

Microelectromechanical systems, or MEMS, is the generic name for a new class of microsystems. Typically, MEMS are: micron- to millimeter-scale devices with moving parts or containing fluids; parts that are batch fabricated using techniques derived from the semiconductor industry; used as sensors or actuators; and are often directly connected or integrated with ICs. The first MEMS design system, MEMCAD, was built in the Senturia Lab at MIT. Now at least three companies market commercial CAD systems for MEMS. The author discusses MEMCAD system's capabilities     

Exact algorithms for the job sequencing and tool switching problem

The job Sequencing and tool Switching Problem (SSP) involves optimally sequencing jobs and assigning tools to a capacitated magazine in order to minimize the number of tool switches. This article analyzes two integer linear programming formulations for the SSP. A branch-and-cut algorithm and a branch-and-bound algorithm are proposed and compared. Computational results indicate that instances involving up to 25 jobs can be solved optimally using the branch-and-bound approach.     

Physical and Sexual Intimate Partner Violence Among Women in Methadone Maintenance Treatment.

Although several studies have examined the relationship between intimate partner violence (IPV) and drug use among women in drug treatment programs, more information is needed to delineate differences, as a function of the specific drug used. Data from a random sample of 416 women attending methadone programs were analyzed to elucidate the differential associations between IPV and use of the following: marijuana only, cocaine only, heroin only, or cocaine and heroin. Prevalence of IPV among this sample far exceeded estimates from the general population. After adjusting for sociodemographic variables, use of cocaine only was significantly associated with an increased likelihood of experiencing IPV compared with no drug use. Similar results were found for women using both cocaine and heroin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of macromolecular architecture on the critical aggregation concentration of large amphiphilic starch derivatives

A range of hyperbranched emulsifiers were prepared by reaction between starch and 2-octen-1-yl succinic anhydride (OSA, commonly used in the food industry), under slightly basic conditions in water, leading to starches bearing hydrophobic OSA groups randomly distributed along the chains. By using different starch backbones and varying the amount of OSA during the synthesis, amphiphilic OSA-modified starches were obtained that formed aggregates in water and having controlled structural parameters. These parameters were characterized using ¹H NMR, multiple-angle laser light scattering and size-exclusion chromatography. The critical aggregation concentration (CAC) was measured for samples with different levels of OSA modification, of macromolecular size and degree of starch branching. Increasing the dispersity in macromolecular size and/or degree of OSA substitution noticeably decreased the CAC. The results are interpreted in terms of the branching structure and conformation of the modified starches: all findings can be understood in terms of the various influences of molecular size, composition and flexibility. The structural factors affecting the CAC of large hyperbranched surfactants are found to be similar to those seen with smaller and simpler branched synthetic surfactants.