Enhanced mixed integer programming model for a transfer line design problem

Modular machining lines with multi-spindle workstations are considered. A multi-spindle head executes a set of operations. The problem of optimal design or reconfiguration of such lines is considered here. The set of all available spindle heads, operations executed by each spindle head, spindle head times and costs are assumed to be known. There are operations which can be executed by one of several candidate spindle heads, i.e., in different configuration with other operations. The problem consists in the choice of spindle heads from the given set and their assignment to workstations. The goal is to minimize the line cost while satisfying the precedence, inclusion and exclusion constraints. This problem is an extension of well known assembly line balancing and equipment selection problem. In our previous work, we proposed a MIP model which was significantly limited as to the size of the problems treated. In this paper, quite a few original approaches are suggested to improve the previous MIP model. The numerical tests reported show that the calculation time is drastically decreased, thereby expanding the model to larger and more realistic industrial problems.     

Determination of nanoparticle dimensions in colloidal solutions with elemental analysis in an electrothermal atomic-absorption spectrometer

A method is proposed for evaluating nanoparticle dimensions based on the difference in atomization kinetics for true and colloidal solutions in graphite furnaces of atomic-absorption spectrometers. The method makes it possible not only to analyze the elemental composition of colloidal nanoparticles, but also to determine their dimensions. It is proven for spherical colloidal gold particles.     

Automaton theory of collective measurements

The aggregation of individual measurements of an unknown parameter in a collective estimate is considered. A theory is constructed that reduces the problem to calculation of the output process of a dynamic automaton model of the measurement system. Translated from Izmeritel'naya Tekhnika, No. 2, pp. 15–20, February, 2000.     

"Generalized single-case randomization tests: Flexible analyses for a variety of situations": Erratum.

Reports an error in "Generalized single-case randomization tests: Flexible analyses for a variety of situations" by Joel R. Levin and Bruce E. Wampold (School Psychology Quarterly, 1999[Spr], Vol 14[1], 59-93). (1) In Table 5 (p. 76), in the cell associated with the third row and third column, the upper value of 18.3 should be 18.73. (2) On p. 81, in the section titled "Simultaneous Start-Point Randomization for Matched Pairs of Units," the sentence beginning in line 10 should read: "With k? acceptable start points for the first pair and k? for the second, there would be k?k? summed sums and null hypothesis-compatible summed differences for the randomization distribution to test Rgen and Rcomp, respectively (as indicated in the Appendix, p. 89)." (The following abstract of the original article appeared in record 1999-10944-004.) A general class of single-case statistical procedures, derived from previously developed nonparametric randomization tests, is presented. These procedures are widely applicable in behavioral and educational research contexts in which only a few experimental "units" (individuals, small groups, or classrooms) are the recipients of one or more experimental treatments or interventions. Specifically illustrated are designs that focus on both the general and comparative effectiveness of alternative interventions (including control/placebo treatments), multiple units with differentiable characteristics (i.e., intervention by unit characteristic interactions), and multiple outcome measures (i.e., intervention by outcome measure interactions). Also provided are operational modifications that enhance the internal validity of studies incorporating single-case randomization-based analyses. Appropriate cautions and issues surrounding the use of these procedures are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain activation while thinking about the self from another person’s perspective after traumatic brain injury in adolescents.

Deficits in self awareness and taking the perspective of others are often observed following traumatic brain injury (TBI). Nine adolescents (ages 12–19 years) who had sustained moderate to severe TBI after an average interval of 2.6 years and nine typically developing (TD) adolescents underwent functional MRI (fMRI) while performing a perspective taking task (D’Argembeau et al., 2007). Participants made trait attributions either from their own perspective or from that of the significant other. The groups did not differ in reaction time or on a consistency criterion. When thinking of the self from a third-person perspective, adolescents with TBI demonstrated greater activation in posterior brain regions implicated in social cognition, the left lingual gyrus (BA 18) and posterior cingulate (BA 31), extending into neighboring regions not generally associated with social cognition, that is, cuneus (BA 31) and parahippocampal gyrus, relative to TD adolescents. We postulate that adolescents with moderate to severe TBI recruited alternative neural pathways during perspective-taking because traumatic axonal injury disrupted their fronto-parietal networks mediating social cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of the Thrust Performance of a Pulsed Detonation Engine

The problem of modeling the operation cycle of a pulse detonation engine and estimating its highest possible thrust performance is considered. Self-similar and non-self-similar flows in an axisymmetric duct of finite length and variable cross section which arise from detonation propagation from the closed end of the duct are studied for the model of an infinitely thin detonation wave. Analytical and numerical methods are used. Dependences of the average impulse and the average specific impulse on the shape of the side wall of the duct are investigated. The optimal shapes corresponding to the highest thrust performance of the operation cycle are found.