Quantitative Measurement of Cortical Surface Features in Localization-Related Temporal Lobe Epilepsy.

Differences in cortical surface features between healthy controls (n = 48) and patients with temporal lobe epilepsy (n = 46), ages 14-59, were characterized by means of advanced quantitative MRI processing techniques. Cortical surface features of interest included gyral and sulcal curvature, cortical depth, and total cortical surface area. Epilepsy patients and controls differed on measures of gyrification; the abnormalities generalized despite the focal nature of the primary epileptic process. Changes in cortical surface features were associated with increasing chronological age in both groups. Abnormalities in gyrification were associated with cognitive performance and with other morphometric measurements (e.g., surface cerebral spinal fluid). These findings are related to the literature regarding morphometric changes associated with temporal lobe epilepsy and normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ropes: An alternative to strings

Programming languages generally provide a ‘string’ or ‘text’ type to allow manipulation of sequences of characters. This type is usually of crucial importance, since it is normally mentioned in most interfaces between system components. We claim that the traditional implementations of strings, and often the supported functionality, are not well suited to such general-purpose use. They should be confined to applications with specific, and unusual, performance requirements. We present ‘ropes’ or ‘heavyweight’ strings as an alternative that, in our experience leads to systems that are more robust, both in functionality and in performance. Ropes have been in use in the Cedar environment almost since its inception, but this appears to be neither well-known, nor discussed in the literature. The algorithms have been gradually refined. We have also recently built a second similar, but somewhat lighter weight, C-language implementation, which is included in our publically released garbage collector distribution. We describe the algorithms used in both, and give some performance measurements for the C version.     

The effect of task complexity on reaction times in memory scanning and visual discrimination in Parkinson's disease

Within the context of the bradyphrenia debate, two experiments designed to measure the cognitive speed of Parkinson patients (PD) were conducted with 58 subjects. The experiments took the form of a high-speed memory scanning task using memory sets consisting of one-six words or one-six abstract figures. In a visual discrimination task, two simultaneously presented abstract images had to be compared, the complexity of the images being varied through four stages. Motor response was constant, reaction time was the dependent variable. PD differed from matched controls in the level (significant only in scanning) but in neither experiment in the slope of reaction time curves. Interaction group x complexity (MANOVA) was not significant. Correlations between disease parameters and a 'complexity effect' measure were low throughout. However, the link to general intelligence was significant. The findings contradict the conventional bradyphrenia hypothesis.     

Clients, Servers and Broadband — Making a Big Difference

'Broadband is more bandwidth than you can use.' Mark Bagley, Venation, 1999 [1].In a world where the unspoken assumption is that providing more bandwidth will solve Internet access problems, these are provocative words. The historical evidence [2] shows that adding bandwidth merely increases demand — analogous in many ways to the building of more motorways having the effect of increasing traffic problems instead of alleviating them. The result is that the world's appetite for bandwidth continues to outstrip the supply, and the only apparent solution is a spiral of ever-greater demands for bandwidth.To find an equitable solution to this conundrum, the problem itself has been re-assessed to see if there might be an alternative. It is now believed that a combination of technologies can offer a scalable solution to providing the services that people evidently want, but without requiring unfeasibly large bandwidths for network access. This paper describes a solution which uses a mixture of client/server, client-side, and peer-to-peer approaches to provide a novel answer. With mobile computing putting new constraints on the likely connection bandwidth, a technique that allows us to exploit bandwidth effectively could be a powerful weapon for the future. It also allows broadband to reveal its true potential.     

Some methodological considerations for the behavioral genetic analysis of work attitudes.

In a recent article, R. D. Arvey et al (see record 1989-25020-001) argued that about 30% of the variance in job satisfaction was accounted for by workers' genetic make-ups. To demonstrate this, they examined a group of monozygotic twins who had been reared apart. Although this method has been used widely in behavioral genetic research, it contains many hidden threats to validity, which could render suspect numerical estimates of either environmental or genetic effects. We examine some of the threats associated with this type of twin research, emphasizing the problems involved in quantifying the heritability of job satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monitoring of particle swarm optimization

In this paper, several diversity measurements will be discussed and defined. As in other evolutionary algorithms, first the population position diversity will be discussed followed by the discussion and definition of population velocity diversity which is different from that in other evolutionary algorithms since only PSO has the velocity parameter. Furthermore, a diversity measurement called cognitive diversity is discussed and defined, which can reveal clustering information about where the current population of particles intends to move towards. The diversity of the current population of particles and the cognitive diversity together tell what the convergence/divergence stage the current population of particles is at and which stage it moves towards.     

Optimization-based locomotion planning,estimation, and control design for the atlas humanoid robot

This paper describes a collection of optimization algorithms for achieving dynamic planning, control, and state estimation for a bipedal robot designed to operate reliably in complex environments. To make challenging locomotion tasks tractable, we describe several novel applications of convex, mixed-integer, and sparse nonlinear optimization to problems ranging from footstep placement to whole-body planning and control. We also present a state estimator formulation that, when combined with our walking controller, permits highly precise execution of extended walking plans over non-flat terrain. We describe our complete system integration and experiments carried out on Atlas, a full-size hydraulic humanoid robot built by Boston Dynamics, Inc.     

Efficient Computation of the Euclidean Distance Transform

We present a simple algorithm for the Euclidean distance transform of a binary image that runs more efficiently than other algorithms in the literature. We show that our algorithm runs in optimal time for many architectures and has optimal cost for the RAM and EREW PRAM.