Effects of Reflectivity/Impulsivity on IELTS Candidates’ Band Scores in the Speaking Module of the Test

AbstractAmong the four skills assessed in proficiency exams speaking is said to be one of the most difficult ones. Due to the significance of this skill, all the factors affecting the candidates’ success should be taken into account. Of these factors learning styles seem to play a major role in candidates’ performance. This study, therefore, was conducted to examine whether there is any relationship between Reflectivity and Impulsivity as two learning styles in cognitive domain and IELTS candidates’ band scores in the speaking module. To fulfill the goal of the study, 52 IELTS candidates from two institutes in Shiraz were chosen. The two instruments used in this study consisted of Yando and Kagan's (1965) adult/adolescent version of MFFT to divide the participants into reflectives and impulsives and the test of speaking. After analyzing the data it was found that there is no relationship between the dimensions of Reflectivity and Impulsivity and IELTS candidates’ band scores, nor between the components of these dimensions. Findings also indicated that there is no difference between R/I in achieving a higher band score

Simulation of the In-plane and Out-of-plane Seismic Performance of Nonstructural Partition Walls

Although recent years have witnessed progress in the experimental and analytical simulation of nonstructural partition walls, a robust solution to prevent extensive damage to these walls has not been found. This is due in part to the lack of validated comprehensive analytical tools to better understand and simulate these walls. The current study supports this field of research through proposing a reliable generic method, for the first time, to analytically model the in-plane and out-of-plane seismic performance of partition walls with various configurations.Initially, a series of full-scale experiments is performed at the UNR-NEES site to investigate the system-level response and damage mechanisms of nonstructural systems, including cold-formed steel-framed (CSF) gypsum partition walls. The experiments reveal that the seismic performance of partition walls depends on the performance of the connections (e.g. gypsum board-to-stud/track connections) as well as the out-of-plane properties of the return walls. Accordingly, a series of component-level experiments (more than 130 experiments) is designed and conducted to characterize the cyclic response of the wall connections, namely gypsum board-to-stud/track, stud-to-track and track-to-concrete connections. The experimental data is used to propose and calibrate analytical nonlinear material models for the connections in OpenSees. Subsequently, the connection models are employed to propose a novel detailed and yet computationally efficient modeling methodology for nonstructural partition walls. In this methodology, the in-plane and out-of-plane nonlinear behaviors of the connections are represented by hysteretic load-deformation springs, which have been calibrated using the component-level experimental data. The steel framing members are modeled by nonlinear beam elements and the gypsum boards are simulated using linear four-node shell elements while. The representative models of corner connections are also assembled accounting for stud configurations, stud-to-stud and gypsum-to-stud screw attachments, and gypsum-to-gypsum contacts. The proposed procedure is used to generate analytical models of four configurations of experiments at the University of Buffalo as well as the analytical model of a C-shaped wall system, tested at the University of Nevada, Reno. Comparison of analytical and experimental results shows that the analytical model successfully estimates the force-displacement response, the out-of-plane dynamic characteristics, and the out-of-plane acceleration responses of partition walls. In addition, the model can predict the possible damage mechanisms in partition walls. The procedure proposed here can be adopted in future studies by researchers and also development engineers to assess the seismic performance of partition walls with various dimensions and construction details, especially where test data is not available

Wireless power transfer for combined sensing and stimulation in implantable biomedical devices

Actuellement, il existe une forte demande de Headstage et de microsystèmes intégrés implantables pour étudier l’activité cérébrale de souris de laboratoire en mouvement libre. De tels dispositifs peuvent s’interfacer avec le système nerveux central dans les paradigmes électriques et optiques pour stimuler et surveiller les circuits neuronaux, ce qui est essentiel pour découvrir de nouveaux médicaments et thérapies contre des troubles neurologiques comme l’épilepsie, la dépression et la maladie de Parkinson. Puisque les systèmes implantables ne peuvent pas utiliser une batterie ayant une grande capacité en tant que source d’énergie primaire dans des expériences à long terme, la consommation d’énergie du dispositif implantable est l’un des principaux défis de ces conceptions. La première partie de cette recherche comprend notre proposition de la solution pour diminuer la consommation d’énergie des microcircuits implantables. Nous proposons un nouveau circuit de décalage de niveau qui convertit les niveaux de signaux sub-seuils en niveaux ultra-bas à haute vitesse en utilisant une très faible puissance et une petite zone de silicium, ce qui le rend idéal pour les applications de faible puissance. Le circuit proposé introduit une nouvelle topologie de décaleur de niveau de tension utilisant un condensateur de décalage de niveau pour augmenter la plage de tensions de conversion, tout en réduisant considérablement le retard de conversion. Le circuit proposé atteint un délai de propagation plus court et une zone de silicium plus petite pour une fréquence de fonctionnement et une consommation d’énergie donnée par rapport à d’autres solutions de circuit. Les résultats de mesure sont présentés pour le circuit proposé fabriqué dans un processus CMOS TSMC de 0,18- mm. Le circuit présenté peut convertir une large gamme de tensions d’entrée de 330 mV à 1,8 V et fonctionner sur une plage de fréquence de 100 Hz à 100 MHz. Il a un délai de propagation de 29 ns et une consommation d’énergie de 61,5 nW pour les signaux d’entrée de 0,4 V, à une fréquence de 500 kHz, surpassant les conceptions précédentes. La deuxième partie de cette recherche comprend nos systèmes de transfert d’énergie sans fil proposé pour les applications optogénétiques. L’optogénétique est la combinaison de la méthode génétique et optique d’excitation, d’enregistrement et de contrôle des neurones biologiques. Ce système combine plusieurs technologies telles que les MEMS et la microélectronique pour collecter et transmettre les signaux neuronaux et activer un stimulateur optique via une liaison sans fil. Puisque les stimulateurs optiques consomment plus de puissance que les stimulateurs électriques, l’interface utilise la transmission de puissance par induction en utilisant des moyens innovants au lieu de la batterie avec la petite capacité comme source d’énergie.Notre première contribution dans la deuxième partie fournit un système de cage domestique intelligent basé sur des barrettes multi-bobines superposées à travers un récepteur multicellulaire implantable mince de taille 1×1 cm2, implanté sous le cuir chevelu d’une souris de laboratoire, et unité de gestion de l’alimentation intégrée. Ce système inductif est conçu pour fournir jusqu’à 35,5 mW de puissance délivrée à un émetteur-récepteur full duplex de faible puissance entièrement intégré pour prendre en charge des implants neuronaux à haute densité et bidirectionnels. L’émetteur (TX) utilise une bande ultra-large à impulsions radio basée sur des approches de combinaison, et le récepteur (RX) utilise une topologie à bande étroite à incrémentation de 2,4 GHz. L’émetteur-récepteur proposé fournit un débit de données de liaison montante TX à 500 Mbits/s double et un débit de données de liaison descendante RX à 100 Mbits/s, et est entièrement intégré dans un processus CMOS TSMC de 0,18-mm d’une taille totale de 0,8 mm2 . La puissance peut être délivrée à partir d’un signal de porteuse de 13,56-MHz avec une efficacité globale de transfert de puissance supérieure à 5% sur une distance de séparation allant de 3 cm à 5 cm. Notre deuxième contribution dans les systèmes de collecte d’énergie porte sur la conception et la mise en oeuvre d’une cage domestique de transmission de puissance sans fil (WPT) pour une plate-forme de neurosciences entièrement sans fil afin de permettre des expériences optogénétiques ininterrompues avec des rongeurs de laboratoire vivants. La cage domestique WPT utilise un nouveau réseau hybride de transmetteurs de puissance (TX) et des résonateurs multi-bobines segmentés pour atteindre une efficacité de transmission de puissance élevée (PTE) et délivrer une puissance élevée sur des distances aussi élevées que 20 cm. Le récepteur de puissance à bobines multiples (RX) utilise une bobine RX d’un diamètre de 1 cm et une bobine de résonateur d’un diamètre de 1,5 cm. L’efficacité moyenne du transfert de puissance WPT est de 29, 4%, à une distance nominale de 7 cm, pour une fréquence porteuse de 13,56 MHz. Il a des PTE maximum et minimum de 50% et 12% le long de l’axe Z et peut délivrer une puissance constante de 74 mW pour alimenter le headstage neuronal miniature. En outre, un dispositif implantable intégré dans un processus CMOS TSMC de 0,18-mm a été conçu et introduit qui comprend 64 canaux d’enregistrement, 16 canaux de stimulation optique, capteur de température, émetteur-récepteur et unité de gestion de l’alimentation (PMU). Ce circuit est alimenté à l’intérieur de la cage du WPT à l’aide d’une bobine réceptrice d’un diamètre de 1,5 cm pour montrer les performances du circuit PMU. Deux tensions régulées de 1,8 V et 1 V fournissent 79 mW de puissance pour tout le système sur une puce. Notre dernière contribution est un système WPT insensible aux désalignements angulaires pour alimenter un headstage pour des applications optogénétiques qui a été précédemment proposé par le Laboratoire de Microsystèmes Biomédicaux (BioML-UL) à ULAVAL. Ce système est la version étendue de notre deuxième contribution aux systèmes de collecte d’énergie.Dans la version mise à jour, un récepteur de puissance multi-bobines utilise une bobine RX d’un diamètre de 1,0 cm et une nouvelle bobine de résonateur fendu d’un diamètre de 1,5 cm, qui résiste aux défauts d’alignement angulaires. Dans cette version qui utilise une cage d’animal plus petite que la dernière version, 4 résonateurs sont utilisés côté TX. De plus, grâce à la forme et à la position de la bobine de répéteur L3 du côté du récepteur, la liaison résonnante hybride présentée peut correctement alimenter la tête sans interruption causée par le désalignement angulaire dans toute la cage de la maison. Chaque 3 tours du répéteur RX a été enveloppé avec un diamètre de 1,5 cm, sous différents angles par rapport à la bobine réceptrice. Les résultats de mesure montrent un PTE maximum et minimum de 53 % et 15 %. La méthode proposée peut fournir une puissance constante de 82 mW pour alimenter le petit headstage neural pour les applications optogénétiques. De plus, dans cette version, la performance du système est démontrée dans une expérience in-vivo avec une souris ChR2 en mouvement libre qui est la première expérience optogénétique sans fil et sans batterie rapportée avec enregistrement électrophysiologique simultané et stimulation optogénétique. L’activité électrophysiologique a été enregistrée après une stimulation optogénétique dans le Cortex Cingulaire Antérieur (CAC) de la souris.Our first contribution in the second part provides a smart home-cage system based on overlapped multi-coil arrays through a thin implantable multi-coil receiver of 1×1 cm2 of size, implantable bellow the scalp of a laboratory mouse, and integrated power management circuits. This inductive system is designed to deliver up to 35.5 mW of power delivered to a fully-integrated, low-power full-duplex transceiver to support high-density and bidirectional neural implants. The transmitter (TX) uses impulse radio ultra-wideband based on an edge combining approach, and the receiver (RX) uses a 2.4- GHz on-off keying narrow band topology. The proposed transceiver provides dual-band 500-Mbps TX uplink data rate and 100-Mbps RX downlink data rate, and it is fully integrated into 0.18-mm TSMC CMOS process within a total size of 0.8 mm2. The power can be delivered from a 13.56-MHz carrier signal with an overall power transfer efficiency above 5% across a separation distance ranging from 3 cm to 5 cm. Our second contribution in power-harvesting systems deals with designing and implementation of a WPT home-cage for a fully wireless neuroscience platform for enabling uninterrupted optogenetic experiments with live laboratory rodents. The WPT home-cage uses a new hybrid parallel power transmitter (TX) coil array and segmented multi-coil resonators to achieve high power transmission efficiency (PTE) and deliver high power across distances as high as 20 cm. The multi-coil power receiver (RX) uses an RX coil with a diameter of 1 cm and a resonator coil with a diameter of 1.5 cm. The WPT home-cage average power transfer efficiency is 29.4%, at a nominal distance of 7 cm, for a power carrier frequency of 13.56-MHz. It has maximum and minimum PTE of 50% and 12% along the Z axis and can deliver a constant power of 74 mW to supply the miniature neural headstage. Also, an implantable device integrated into a 0.18-mm TSMC CMOS process has been designed and introduced which includes 64 recording channels, 16 optical stimulation channels, temperature sensor, transceiver, and power management unit (PMU). This circuit powered up inside the WPT home-cage using receiver coil with a diameter of 1.5 cm to show the performance of the PMU circuit. Two regulated voltages of 1.8 V and 1 V provide 79 mW of power for all the system on a chip. Our last contribution is an angular misalignment insensitive WPT system to power up a headstage which has been previously proposed by the Biomedical Microsystems Laboratory (BioML-UL) at ULAVAL for optogenetic applications. This system is the extended version of our second contribution in power-harvesting systems. In the updated version a multi-coil power receiver uses an RX coil with a diameter of 1.0 cm and a new split resonator coil with a diameter of 1.5 cm, which is robust against angular misalignment. In this version which is using a smaller animal home-cage than the last version, 4 resonators are used on the TX side. Also, thanks to the shape and position of the repeater coil of L3 on the receiver side, the presented hybrid resonant link can properly power up the headstage without interruption caused by the angular misalignment all over the home-cage. Each 3 turns of the RX repeater has been wrapped up with a diameter of 1.5 cm, in different angles compared to the receiver coil. Measurement results show a maximum and minimum PTE of 53 % and 15 %. The proposed method can deliver a constant power of 82 mW to supply the small neural headstage for the optogenetic applications. Additionally, in this version, the performance of the system is demonstrated within an in-vivo experiment with a freely moving ChR2 mouse which is the first fully wireless and batteryless optogenetic experiment reported with simultaneous electrophysiological recording and optogenetic stimulation. Electrophysiological activity was recorded after delivering optogenetic stimulation in the Anterior Cingulate Cortex (ACC) of the mouse.Currently, there is a high demand for Headstage and implantable integrated microsystems to study the brain activity of freely moving laboratory mice. Such devices can interface with the central nervous system in both electrical and optical paradigms for stimulating and monitoring neural circuits, which is critical to discover new drugs and therapies against neurological disorders like epilepsy, depression, and Parkinson’s disease. Since the implantable systems cannot use a battery with a large capacity as a primary source of energy in long-term experiments, the power consumption of the implantable device is one of the leading challenges of these designs. The first part of this research includes our proposed solution for decreasing the power consumption of the implantable microcircuits. We propose a novel level shifter circuit which converting subthreshold signal levels to super-threshold signal levels at high-speed using ultra low power and a small silicon area, making it well-suited for low-power applications such as wireless sensor networks and implantable medical devices. The proposed circuit introduces a new voltage level shifter topology employing a level-shifting capacitor to increase the range of conversion voltages, while significantly reducing the conversion delay. The proposed circuit achieves a shorter propagation delay and a smaller silicon area for a given operating frequency and power consumption compared to other circuit solutions. Measurement results are presented for the proposed circuit fabricated in a 0.18-mm TSMC CMOS process. The presented circuit can convert a wide range of the input voltages from 330 mV to 1.8 V, and operate over a frequency range of 100-Hz to 100-MHz. It has a propagation delay of 29 ns, and power consumption of 61.5 nW for input signals 0.4 V, at a frequency of 500-kHz, outperforming previous designs. The second part of this research includes our proposed wireless power transfer systems for optogenetic applications. Optogenetics is the combination of the genetic and optical method of excitation, recording, and control of the biological neurons. This system combines multiple technologies such as MEMS and microelectronics to collect and transmit the neuronal signals and to activate an optical stimulator through a wireless link. Since optical stimulators consume more power than electrical stimulators, the interface employs induction power transmission using innovative means instead of the battery with the small capacity as a power source

Flow around stationary and oscillating polygonal cylinders

Understanding the intricate flow dynamics around polygonal cylinders is crucial for various engineering applications, including the design of marine cables, offshore platforms and utilising the phenomenon of Flow Induced Vibration (FIV) to harvest energy from wind or ocean currents. In this dissertation, flow around stationary and oscillating polygonal cylinders is studied using numerical and experimental methods. Large eddy simulation (LES) is used to study the effect of the incidence angle on polygons of N=5-8 at a fixed Reynolds number of Re=10,000. In total, six incidence angles are studied on each cylinder ranging from face to corner orientations, thus covering the entire incidence spectrum. It is found that because of the asymmetric nature of polygonal cross sections at most incidence angles, the flow separation characteristics and hence the induced base pressure distribution and the aerodynamic forces exhibit unique and complex dependence on incidence angle and N. Furthermore, it is found that the separated shear layers behind the cylinders are highly dynamic, manifesting a flapping motion with a frequency matching the Strouhal frequency and a strength varying significantly at different incidence angles. Equations for the separation points are analytically derived and found to be consistent with available experimental results. Experimentally, flow induced vibration (FIV) of a polygon of N=5 as well as a circular cylinder is studied in a recirculating wind tunnel. A series of free oscillation experiments are carried out in order to explore galloping behaviour as well as the lock-in region for vortex induced vibration (VIV). It is found that VIV in the case of N=5 is substantially stronger than the circular cylinder in a similar mass ratio. VIV maximum amplitude change non-monotonically with incidence angle, and it is smaller in incidences where galloping is dominant

SEMIGROUP ACTION FOR HUTCHITSON OPERATOR OF ITERATED FUNCTION SYSTEM

In this article, we are trying to see the Iterated function system or more generally a skew product as formation a semigroup action system. We will try to implement more semigroup action properties on itself. For this purpose, we introduce a semigroup action corresponding Iterated function system and explain more properties of itself then with considering Hutchitson operator on Iterated function system, we try consider the corresponding semigroup action for Iterated function system and achive more its properties

Short Communication A note on "The Ideal Generated by Codense Sets and the Banach Localization Property"

In this note we show by producing counter examples that some results which appeared in the articles by Jankovic and Hamlett [3] are incorrect

ORBIT PROPAGATION AND DETERMINATION ALGORITHMS FOR SATELLITE GROUND STATIONS

The satellite orbital parameters are essential for satellite operations. With these parameters, it is possible to estimate the satellite position in the recent past and near future, which is essential to effectively plan satellite operations and associate satellite telemetry with geographical locations.However, for small or medium satellite operators who do not possess the infrastructure required to track their satellites, the problem of determining the satellite orbit is problematic. To access the orbit for their satellites, these organizations have to rely on third parties such as Celestrak. These entities provide the service free of charge but do not provide orbital parameters with the required frequency. Furthermore, another problem may arise during the mission\u27s early phases. Suppose the satellite is launched together with a number of other satellites, as is often done for small satellites. In that case, it is also not known in the first days or weeks of the mission which orbital parameters are from which satellite launched in the group. This project aims to address the problem of orbital parameter determination by using GPS data, Kalman filters and AI (genetic algorithm)