Synergy Between an Improved Covariate Unit Root Test and Cross-sectionally Dependent Panel Data Unit Root Tests, with two Applications

This paper proposes the use of an improved covariate unit root test which exploits the cross-sectional dependence information when the panel data null hypothesis of a unit root is rejected. More explicitly, to increase the power of the test, we suggest the utilization of more than one covariate and offer several ways to select the ‘best’ covariates from the set of potential covariates represented by the individuals in the panel. Employing our methods, we investigate the Prebish-Singer hypothesis for nine commodity prices. Our results show that this hypothesis holds for all but the price of petroleum.

Vehicle-barrier tracking of a scaled crash test for roadside barrier design

In this paper the tracking system used to perform a scaled vehicle-barrier crash test is reported. The scaled crash test was performed as part of a wider project aimed at designing a new safety barrier making use of natural building materials. The scaled crash test was designed and performed as a proof of concept of the new mass-based safety barriers and the study was composed of two parts: the scaling technique and of a series of performed scaled crash tests. The scaling method was used for 1) setting the scaled test impact velocity so that energy dissipation and momentum transferring, from the car to the barrier, can be reproduced and 2) predicting the acceleration, velocity and displacement values occurring in the full-scale impact from the results obtained in a scaled test. To achieve this goal the vehicle and barrier displacements were to be recorded together with the vehicle accelerations and angular velocities. These quantities were measured during the tests using acceleration sensors and a tracking system. The tracking system was composed of a high speed camera and a set of targets to measure the vehicle linear and angular velocities. A code was developed to extract the target velocities from the videos and the velocities obtained were then compared with those obtained integrating the accelerations provided by the sensors to check the reliability of the method.

TEC4SEA - A Modular Platform for Research, Test and Validation of Technologies Supporting a Sustainable Blue Economy

This paper presents the TEC4SEA research infrastructure created in Portugal to support research, development, and validation of marine technologies. It is a multidisciplinary open platform, capable of supporting research, development, and test of marine robotics, telecommunications, and sensing technologies for monitoring and operating in the ocean environment. Due to the installed research facilities and its privileged geographic location, it allows fast access to deep sea, and can support multidisciplinary research, enabling full validation and evaluation of technological solutions designed for the ocean environment. It is a vertically integrated infrastructure, in the sense that it possesses a set of skills and resources which range from pure conceptual research to field deployment missions, with strong industrial and logistic capacities in the middle tier of prototype production. TEC4SEA is open to the entire scientific and enterprise community, with a free access policy for researchers affiliated with the research units that ensure its maintenance and sustainability. The paper describes the infrastructure in detail, and discusses associated research programs, providing a strategic vision for deep sea research initiatives, within the context of both the Portuguese National Ocean Strategy and European Strategy frameworks.

An Exact Schedulability Test for Global FP Using State Space Pruning

Presented at 23rd International Conference on Real-Time Networks and Systems (RTNS 2015). 4 to 6, Nov, 2015, Main Track. Lille, France.

Set-up and evaluation of a mid-infrared reflectometer and investigation of the optical properties of doped tin telluride

A system comprised of a Bomem interferometer and a LT3-110 Heli-Tran cryostat was set up to measure the reflectance of materials in the mid-infrared spectral region. Several tests were conducted to ensure the consistency and reliability of the system. Silicon and Chromium, two materials with well known optical properties were measured to test the accuracy of the system, and the results were found to be in good agreement with the literature. Reflectance measurements on pure SnTe and several Pb and Mn-doped alloys were carried out. These materials were chosen because they exhibit a strong plasma edge in the mid infrared region. The optical conductivity and several related optical parameters were calculated from the measured reflectance. Very low temperature measurements were carried out in the far-infrared on Sn9SMn2Te, and the results are indicative of a spin glass phase at 0.8 K. Resistivity measurements were made at room temperature. The resistivity values were found, as expected, to decrease with increasing carrier concentration and to increase with increasing manganese concentration.

Cognitive set, absorption, and achievement as moderators of the perceptual closure effect in picture priming /

The present study examined individual differences in Absorption and fantasy, as well as in Achiievement and achievement striving as possible moderators of the perceptual closure effect found by Snodgrass and Feenan (1990). The study also examined whether different instructions (experiential versus instrumental) interact with the personality variables to moderate the relationship between priming and subsequent performance on a picture completion task. 1 28 participants completed two sessions, one to fill out the MPQ and NEO personality inventories and the other to complete the experimental task. The experimental task consisted of a priming phase and a test phase, with pictures presented on a computer screen for both phases. Participants were shown 30 pictures in the priming phase, and then shovm the 30 primed pictures along with 30 new pictures for the test phase. Participants were randomly assigned to receive one of the two different instruction sets for the task. Two measures of performance were calculated, most fragmented measure and threshold. Results of the present study confirm that a five-second exposure time is long enough to produce the perceptual closure effect. The analysis of the two-way interaction effects indicated a significant quadratic interaction of Absorption with priming level on threshold performance. The results were in the opposite direction of predictions. Possible explanations for the Absorption results include lack of optimal conditions, lack of intrinsic motivation and measurement problems. Primary analyses also revealed two significant between-subject effects of fantasy and achievement striving on performance collapsed across priming levels. These results suggest that fantasy has a beneficial effect on performance at test for pictures primed at all levels, whereas achievement striving seems to have an adverse effect on performance at test for pictures primed at all levels. Results of the secondary analyses with a revised threshold performance measure indicated a significant quadratic interaction of Absorption, condition and priming level. In the experiential condition, test performance, based on Absorption scores for pictures primed at level 4, showed a positive slope and performance for pictures primed at levels 1 and 7 based on Absorption showed a negative slope. The reverse effect was found in the instrumental condition. The results suggest that Absorption, in combination with experiential involvement, may affect implicit memory. A second significant result of the secondary analyses was a linear three-way interaction of Achievement, condition and priming level on performance. Results suggest that as Achievement scores increased, test performance improved for less fragmented primed pictures in the instrumental condition and test performance improved for more highly fragmented primes in the experiential condition. Results from the secondary analyses suggest that the revised threshold measure may be more sensitive to individual differences. Results of the exploratory analyses with Openness to Experience, Conscientiousness and agentic positive emotionality (PEM-A) measures indicated no significant effects of any of these personality variables. Results suggest that facets of the scales may be more useful with regard to perceptual research, and that future research should examine narrowly focused personality traits as opposed to broader constructs.

GA approach for finding Rough Set decision rules based on bireducts

Feature selection plays an important role in knowledge discovery and data mining nowadays. In traditional rough set theory, feature selection using reduct - the minimal discerning set of attributes - is an important area. Nevertheless, the original definition of a reduct is restrictive, so in one of the previous research it was proposed to take into account not only the horizontal reduction of information by feature selection, but also a vertical reduction considering suitable subsets of the original set of objects. Following the work mentioned above, a new approach to generate bireducts using a multi--objective genetic algorithm was proposed. Although the genetic algorithms were used to calculate reduct in some previous works, we did not find any work where genetic algorithms were adopted to calculate bireducts. Compared to the works done before in this area, the proposed method has less randomness in generating bireducts. The genetic algorithm system estimated a quality of each bireduct by values of two objective functions as evolution progresses, so consequently a set of bireducts with optimized values of these objectives was obtained. Different fitness evaluation methods and genetic operators, such as crossover and mutation, were applied and the prediction accuracies were compared. Five datasets were used to test the proposed method and two datasets were used to perform a comparison study. Statistical analysis using the one-way ANOVA test was performed to determine the significant difference between the results. The experiment showed that the proposed method was able to reduce the number of bireducts necessary in order to receive a good prediction accuracy. Also, the influence of different genetic operators and fitness evaluation strategies on the prediction accuracy was analyzed. It was shown that the prediction accuracies of the proposed method are comparable with the best results in machine learning literature, and some of them outperformed it.

Changes in cortical and sub-cortical patterns of activity associated with aging during the performance of a lexical set-shifting task

Bien que le passage du temps altère le cerveau, la cognition ne suit pas nécessairement le même destin. En effet, il existe des mécanismes compensatoires qui permettent de préserver la cognition (réserve cognitive) malgré le vieillissement. Les personnes âgées peuvent utiliser de nouveaux circuits neuronaux (compensation neuronale) ou des circuits existants moins susceptibles aux effets du vieillissement (réserve neuronale) pour maintenir un haut niveau de performance cognitive. Toutefois, la façon dont ces mécanismes affectent l’activité corticale et striatale lors de tâches impliquant des changements de règles (set-shifting) et durant le traitement sémantique et phonologique n’a pas été extensivement explorée. Le but de cette thèse est d’explorer comment le vieillissement affecte les patrons d’activité cérébrale dans les processus exécutifs d’une part et dans l’utilisation de règles lexicales d’autre part. Pour cela nous avons utilisé l’imagerie par résonance magnétique fonctionnelle (IRMf) lors de la performance d’une tâche lexicale analogue à celle du Wisconsin. Cette tâche a été fortement liée à de l’activité fronto-stritale lors des changements de règles, ainsi qu’à la mobilisation de régions associées au traitement sémantique et phonologique lors de décisions sémantiques et phonologiques, respectivement. Par conséquent, nous avons comparé l’activité cérébrale de jeunes individus (18 à 35 ans) à celle d’individus âgés (55 à 75 ans) lors de l’exécution de cette tâche. Les deux groupes ont montré l’implication de boucles fronto-striatales associées à la planification et à l’exécution de changements de règle. Toutefois, alors que les jeunes semblaient activer une « boucle cognitive » (cortex préfrontal ventrolatéral, noyau caudé et thalamus) lorsqu’ils se voyaient indiquer qu’un changement de règle était requis, et une « boucle motrice » (cortex postérieur préfrontal et putamen) lorsqu’ils devaient effectuer le changement, les participants âgés montraient une activation des deux boucles lors de l’exécution des changements de règle seulement. Les jeunes adultes tendaient à présenter une augmentation de l’activité du cortex préfrontal ventrolatéral, du gyrus fusiforme, du lobe ventral temporale et du noyau caudé lors des décisions sémantiques, ainsi que de l’activité au niveau de l’aire de Broca postérieur, de la junction temporopariétale et du cortex moteur lors de décisions phonologiques. Les participants âgés ont montré de l’activité au niveau du cortex préfrontal latéral et moteur durant les deux types de décisions lexicales. De plus, lorsque les décisions sémantiques et phonologiques ont été comparées entre elles, les jeunes ont montré des différences significatives au niveau de plusieurs régions cérébrales, mais pas les âgés. En conclusion, notre première étude a montré, lors du set-shifting, un délai de l’activité cérébrale chez les personnes âgées. Cela nous a permis de conceptualiser l’Hypothèse Temporelle de Compensation (troisième manuscrit) qui consiste en l’existence d’un mécanisme compensatoire caractérisé par un délai d’activité cérébrale lié au vieillissement permettant de préserver la cognition au détriment de la vitesse d’exécution. En ce qui concerne les processus langagiers (deuxième étude), les circuits sémantiques et phonologiques semblent se fusionner dans un seul circuit chez les individus âgés, cela représente vraisemblablement des mécanismes de réserve et de compensation neuronales qui permettent de préserver les habilités langagières.

Class Test Generator

A combination of perl scripts and LaTeX files, this generates multiple multiple choice class tests from a single set of questions. You input a list of questions and answers into a text file. The script then produces any number of class tests that can be used, together with master answer sheets, by scrambling the order of the questions and the answers. Includes a detailed README file, but best just to try it and see.

Green ICT Resource Set - INFO2009 Coursework, Bobs' Finest Group

Online resource set which details in full the Green ICT topic and associated areas. Online multiple choice quiz also included to test readers knowledge of topic once the tutorial has been read.

Question Mark Perception - example test questions

This set of questions on astronomy can be used to show the main question types available. You will need to log in using your University username and password

Internal test sets studies in a group of antimalarials

Topological indices have been applied to build QSAR models for a set of 20 antimalarial cyclic peroxy cetals. In order to evaluate the reliability of the proposed linear models leave-n-out and Internal Test Sets (ITS) approaches have been considered. The proposed procedure resulted in a robust and consensued prediction equation and here it is shown why it is superior to the employed standard cross-validation algorithms involving multilinear regression models

Evaluating lexically controlled word lists for open set speech perception testing in profoundly hearing impaired children

This paper evaluates speech perception testing in pediatric cochlear implant users. Using pre-recorded stimulus presentation, the author replicated an earlier experiment comparing the Lexical Neighborhood List (LNT) test to the Phonetically Balanced Kindergarten (PB-K) test in estimating speech perception abilities in hearing impaired children.

On the convergence of the no response test

The no response test is a new scheme in inverse problems for partial differential equations which was recently proposed in [D. R. Luke and R. Potthast, SIAM J. Appl. Math., 63 (2003), pp. 1292–1312] in the framework of inverse acoustic scattering problems. The main idea of the scheme is to construct special probing waves which are small on some test domain. Then the response for these waves is constructed. If the response is small, the unknown object is assumed to be a subset of the test domain. The response is constructed from one, several, or many particular solutions of the problem under consideration. In this paper, we investigate the convergence of the no response test for the reconstruction information about inclusions D from the Cauchy values of solutions to the Helmholtz equation on an outer surface $\partial\Omega$ with $\overline{D} \subset \Omega$. We show that the one‐wave no response test provides a criterion to test the analytic extensibility of a field. In particular, we investigate the construction of approximations for the set of singular points $N(u)$ of the total fields u from one given pair of Cauchy data. Thus, the no response test solves a particular version of the classical Cauchy problem. Also, if an infinite number of fields is given, we prove that a multifield version of the no response test reconstructs the unknown inclusion D. This is the first convergence analysis which could be achieved for the no response test.

Instance generators and test suites for the multiobjective quadratic assignment problem

We describe, and make publicly available, two problem instance generators for a multiobjective version of the well-known quadratic assignment problem (QAP). The generators allow a number of instance parameters to be set, including those controlling epistasis and inter-objective correlations. Based on these generators, several initial test suites are provided and described. For each test instance we measure some global properties and, for the smallest ones, make some initial observations of the Pareto optimal sets/fronts. Our purpose in providing these tools is to facilitate the ongoing study of problem structure in multiobjective (combinatorial) optimization, and its effects on search landscape and algorithm performance.