A relativistic temporal algebra for efficient design of distributed systems

Adequate methods for checking the specification and design of distributed systems must allow for reasoning about asynchronous activities; efficient methods must perform the reasoning in polynomial time. This paper lays the groundwork for such an efficient deductive system by providing a very general temporal relation algebra that can be used by constraint propagation techniques to perform the required reasoning. Major choices exist when selecting an appropriate temporal model: discrete/dense, linear/nonlinear, and point/interval. James Allen and others have indicated the possible atomic relations between two intervals for the dense-linear-interval model, while Anger, Ladkin, and Rodriguez have shown those needed for a dense-branching-interval model. Rodriguez and Anger further developed a dense-relativistic-interval model based on Lamport'sprecede andcan affect arrows, determining a large number of atomic relations. This paper shows that those same atomic relations are exactly the correct ones for intervals in dense relativistic space-time if intervals are taken as pairs of points (E _s ,E _f ) in space-time such that it is possible to move fromE _s toE _f at less than the speed of light. The relations are defined and named consistently with the earlier work of Rodriguez and Anger, and the relationship between the two models is pursued. The relevance of the results to the verification of distributed specifications and algorithms is discussed.     

Structure and bonding of ArClF: Intermolecular potential surface

The ground-state potential surface of the Ar-ClF complex is determined by restricted coupled-cluster with single and double excitations and a noniterative perturbation treatment of triple excitation (RCCSD(T)) calculations, using augmented correlation consistent basis sets supplemented with an additional set of midbond functions. Three local minima are found for the Ar-ClF, which correspond to linear Ar-Cl-F and Ar-F-Cl configurations and a near T-shaped structure. The well depths and the equilibrium distances are 283.62 cm⁻¹ at 3.84 Å and 128.96 cm⁻¹ at 4.31 Å for the linear ones and 173.13 cm⁻¹ at 3.58 Å for the one at θ = 107.5°. Bound-state calculations are carried out and the linear Ar-Cl-F structure is found to be the most stable one, in accordance with the experiment. Dissociation energies, intermolecular distances, and vibrational frequencies are computed and compared with available experimental data.     

Enzyme‐catalyzed regioselective synthesis of sugar esters and related compounds

In this review, a comprehensive and illustrative survey is made of the regioselective synthesis of esters of sugars and related compounds using lipases. The main emphasis has been given to the screening and use of commercially available lipases for the enzymatic esterification of neutral monosaccharides, disaccharides, sugar alcohols and their selected ether and ester derivatives. The effect of solvents and solubilizing agents in improving the yields of the resultant sugar fatty acid esters has been incorporated. Further, solvent‐free esterification with molten fatty acids, use of ionic liquids and microwave radiations for improvement in the methodology have also been discussed. Copyright © 2006 Society of Chemical Industry     

Housing Attainment of Immigrants from the former Soviet Union in Israel: A Cost/Benefit Approach

The present study examines the extent that national housing policy and demographic and human capital factors affect the odds of homeownership and quality of housing. A cost/benefit theoretical conceptualization with a sample of 19 000 Russian immigrants who arrived in Israel in 1989-90 was used to examine how the benefits of homeownership (location, size and pricing) 'stood against' a set of costs (commuting time required, housing age and size). A set of demographic and human capital factors were employed to control for socio-economic effects such as age, gender, family size, labour force participation and occupational status. The benefits of homeownership for immigrants in Israel also proved to involve some costs: migrating to smaller localities and commuting to metropolitan areas where occupational opportunities are higher. The findings suggest that while homeownership is widespread, it imposes a burden on new immigrants as well. This implies that social policy with regard to housing, especially low-priced housing, should consider the possibility of expanding public and market services in an appropriate way that will increase social inclusion and lessen the likelihood of structural segregation.     

Theoretical study of photoresponse to pulsed radiation in n-InSb in the temperature range 77–300 K

The results of a theoretical simulation of a transient experiment in n-InSb in the temperature range 77–300 K, are reported. Minority carrier lifetimes for the three recombination processes, radiative, SRH and Auger, have been calculated at different temperatures using the temperature dependence of intrinsic carrier concentration,n _i , and density of states effective mass of heavy holes,m _d. It was found that around room temperature the lifetimes for the three processes become comparable and at higher temperatures the Auger lifetime becomes dominant. This fact was ignored in previous work where only SRH and radiative processes were considered in the calculation of effective lifetime. The present results of effective lifetime in n-InSb are in reasonably good agreement with the results obtained previously. The effect of higher time modes on the decay of photoresponse to pulsed radiation is discussed. An instantaneous time constant has been defined and its variation with time at different temperatures has been studied.On leave from Atma Ram Sanatan Dharma College, University of Delhi, New Delhi 110021, India.     

Did I do it or did I only imagine doing it?

Conducted 5 experiments with 180 undergraduates to investigate the memory and decision process involved in distinguishing between memories of doing and imagining doing. Ss were presented with items (typically line drawings) and told to trace or imagine tracing the outline or simply look at them. Ss were then tested for their ability to recognize the item and to identify the activity performed on it. Selected findings indicate that, although the accuracy of activity identification varied, type of activity did not affect item recognition. Tracing and imagining were more confusable in memory than were tracing and looking. The pattern of item recognition and activity identification remained the same whether or not Ss expected to be tested for their memory of the activity performed. Memory for imagining was more susceptible to confusion or multiple interpretation than was memory for tracing or looking, suggesting that accuracy of image identifications is affected by the number and the nature of the alternative activities under consideration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A learning algorithm for the classification of dynamic events using a neuron-like dynamic tree

The use of neuron-like networks (NN) for pattern recognition has a well-established history and numerous current applications. Most such applications are to static patterns while the theory developed for temporally changing visual patterns usually assumes rigid objects with well-defined boundaries. In applications such as analysis of cardiac movement, however, the object is flexible and the images are often imperfect. the authors current model for NN activity captures the dynamic nature of the signal processing of the neural dendritic tree, allowing both faster learning of dynamic patterns and a very reduced number of receptors required for distinguishing diverse types of motion or changes. the design of the NN model is presented and a training algorithm which exhibits in practice extremely fast convergence (as few as 15 iterations) to near optimal recognition behavior is introduced. © 1993 John Wiley & Sons, Inc.