No abstract

Reachability testing is an approach to verifying concurrent programs. During reachability testing, every partially ordered synchronization sequence of a program with a given input is exercised exactly once. In this paper, we present the design and implementation of a distributed reachability testing algorithm for a cluster of workstations. This algorithm allows different test sequences to be exercised concurrently by different workstations without any synchronization, and without any duplication of sequences among workstations. Dynamic load balancing is performed using a work‐stealing scheme. A novel aspect of this scheme is that work‐stealing requests progress in rounds. This round‐based structure identifies overloaded workstations to target for work stealing. Empirical studies show good speedup for four benchmark Java programs and one Lotos specification. Copyright © 2010 John Wiley & Sons, Ltd.

We report here on our investigations of structure-property correlations in soluble organic semiconductors. To develop formulations for mass printing of semiconductor films, a series of alkoxy-and alkyldisubstituted symmetric phenylene thiophene co-oligomers (disubstituted-PTTP) were systematically synthesized to achieve high solubility in common organic solvents. Solubilities of up to 40% by weight in tetrahydrofuran at room temperature were achieved by introducing branching at various positions on the terminal chains, and by silyloxy or hydroxy functionalization of the chains. Concomitant with the solubility increase, however, mobilities and I on /I off ratios of these materials in TFT devices fall several orders of magnitude. X-ray diffraction of the semiconductor films reveals increasing tilt of the molecular orientation on the substrate with an increase in steric crowding near the PTTP core. This indicates that π-stacking of these molecules along the channel between the source and drain is hampered and leads to the observed inverse interdependence of solubility and the field effect mobility.

No abstract

No abstract