Mutual inhibition and capacity sharing during parallel preparation of serial eye movements

Many common activities, like reading, scanning scenes, or searching for an inconspicuous item in a cluttered environment, entail serial movements of the eyes that shift the gaze from one object to another. Previous studies have shown that the primate brain is capable of programming sequential saccadic eye movements in parallel. Given that the onset of saccades directed to a target are unpredictable in individual trials, what prevents a saccade during parallel programming from being executed in the direction of the second target before execution of another saccade in the direction of the first target remains unclear. Using a computational model, here we demonstrate that sequential saccades inhibit each other and share the brain's limited processing resources (capacity) so that the planning of a saccade in the direction of the first target always finishes first. In this framework, the latency of a saccade increases linearly with the fraction of capacity allocated to the other saccade in the sequence, and exponentially with the duration of capacity sharing. Our study establishes a link between the dual-task paradigm and the ramp-to-threshold model of response time to identify a physiologically viable mechanism that preserves the serial order of saccades without compromising the speed of performance.

Pattern-growth based frequent serial episode discovery

Frequent episode discovery is a popular framework for pattern discovery from sequential data. It has found many applications in domains like alarm management in telecommunication networks, fault analysis in the manufacturing plants, predicting user behavior in web click streams and so on. In this paper, we address the discovery of serial episodes. In the episodes context, there have been multiple ways to quantify the frequency of an episode. Most of the current algorithms for episode discovery under various frequencies are apriori-based level-wise methods. These methods essentially perform a breadth-first search of the pattern space. However currently there are no depth-first based methods of pattern discovery in the frequent episode framework under many of the frequency definitions. In this paper, we try to bridge this gap. We provide new depth-first based algorithms for serial episode discovery under non-overlapped and total frequencies. Under non-overlapped frequency, we present algorithms that can take care of span constraint and gap constraint on episode occurrences. Under total frequency we present an algorithm that can handle span constraint. We provide proofs of correctness for the proposed algorithms. We demonstrate the effectiveness of the proposed algorithms by extensive simulations. We also give detailed run-time comparisons with the existing apriori-based methods and illustrate scenarios under which the proposed pattern-growth algorithms perform better than their apriori counterparts. (C) 2013 Elsevier B.V. All rights reserved.

An efficient design of serial and parallel memory using Quantum dot cellular automata

Quantum cellular automata (QCA) is a new technology in the nanometer scale and has been considered as one of the alternative to CMOS technology. In this paper, we describe the design and layout of a serial memory and parallel memory, showing the layout of individual memory cells. Assuming that we can fabricate cells which are separated by 10nm, memory capacities of over 1.6 Gbit/cm2 can be achieved. Simulations on the proposed memories were carried out using QCADesigner, a layout and simulation tool for QCA. During the design, we have tried to reduce the number of cells as well as to reduce the area which is found to be 86.16sq mm and 0.12 nm2 area with the QCA based memory cell. We have also achieved an increase in efficiency by 40%.These circuits are the building block of nano processors and provide us to understand the nano devices of the future.

Discovering compressing serial episodes from event sequences

Most pattern mining methods yield a large number of frequent patterns, and isolating a small relevant subset of patterns is a challenging problem of current interest. In this paper, we address this problem in the context of discovering frequent episodes from symbolic time-series data. Motivated by the Minimum Description Length principle, we formulate the problem of selecting relevant subset of patterns as one of searching for a subset of patterns that achieves best data compression. We present algorithms for discovering small sets of relevant non-redundant episodes that achieve good data compression. The algorithms employ a novel encoding scheme and use serial episodes with inter-event constraints as the patterns. We present extensive simulation studies with both synthetic and real data, comparing our method with the existing schemes such as GoKrimp and SQS. We also demonstrate the effectiveness of these algorithms on event sequences from a composable conveyor system; this system represents a new application area where use of frequent patterns for compressing the event sequence is likely to be important for decision support and control.

The reverse self-dual serial cost-sharing rule

In this study we define a cost sharing rule for cost sharing problems. This rule is related to the serial cost-sharing rule defined by Moulin and Shenker (1992). We give some formulas and axiomatic characterizations for the new rule. The axiomatic characterizations are related to some previous ones provided by Moulin and Shenker (1994) and Albizuri (2010).

El serial clásico de la BBC: la adaptación literaria como servicio público

Eguíluz, Federico; Merino, Raquel; Olsen, Vickie; Pajares, Eterio; Santamaría, José Miguel (eds.)

Intermediate serial cost-sharing rules

In this paper we give a generalization of the serial cost-sharing rule defined by Moulin and Shenker (1992) for cost sharing problems. According to the serial cost sharing rule, agents with low demands of a good pay cost increments associated with low quantities in the production process of that good. This fact might not always be desirable for those agents, since those cost increments might be higher than others, for example with concave cost functions. In this paper we give a family of cost sharing rules which allocates cost increments in all the possible places in the production process. And we characterize axiomatically each of them by means of an axiomatic characterization related to the one given for the serial cost-sharing rule by Moulin and Shenker (1994).

The fourfold serial killer in Bret Easton Elliss American Psycho

Patrick Bateman, o protagonista narrador do romance American Psycho (1991), de Bret Easton Ellis, confunde por ser rico, bonito e educado e, ao mesmo tempo, torturador, assassino e canibal. Mas esta personalidade antagônica não o torna singular. O que o particulariza são as quatro faces que ele apresenta ao longo de sua narrativa: (1) ele consome mercadorias e humanos, (2) compete para ter reconhecimento, (3) provoca horror por suas ações, e (4) não é um narrador confiável. Sendo um yuppie (termo popular usado nos Estados Unidos na década de 1980 para denominar jovens e bem sucedidos profissionais urbanos), Bateman é materialista e hedonista. Ele está imerso em uma sociedade de consumo, fato que o impossibilita de perceber diferenças entre produtos e pessoas. Sendo um narcisista, ele se torna um competidor em busca de admiração. No entanto, Bateman também é um serial killer e suas descrições detalhadas de torturas e assassinatos horrorizam. Por fim, nós leitores duvidamos de sua narrativa ao notarmos inconsistências e ambiguidades. Zygmunt Bauman (2009) afirma que uma sociedade extremamente capitalista transforma tudo que nela existe em algo consumível. Christopher Lasch (1991) afirma que o lendário Narciso deu lugar a um novo, controverso, dependente e menos confiante. A maioria das vítimas de Bateman são membros de grupos socialmente marginalizados, como mendigos, homossexuais, imigrantes e prostitutas, o que o torna uma identidade predatória, segundo Arjun Appadurai (2006). A voz autodiegética e a narrativa incongruente do protagonista, contudo, impedem que confiemos em suas palavras. Estas são as quatro faces que pretendo apresentar deste serial killer

The atom pencil: serial writing in the sub-micrometre domain

The atom pencil we describe here is a versatile tool that writes arbitrary structures by atomic deposition in a serial lithographic process. This device consists of a transversely laser-cooled and collimated cesium atomic beam that passes through a 4-pole atom-flux concentrator and impinges on to micron- and sub-micron-sized apertures. The aperture translates above a fixed substrate and enables the writing of sharp features with sizes down to 280 nm. We have investigated the writing and clogging properties of an atom pencil tip fabricated from silicon oxide pyramids perforated at the tip apex with a sub-micron aperture.