67 research outputs found
Does the Side of Stroke Matter? An fMRI Study on the Role of Stroke Laterality on the Action Observation Network
No full textAbstract
Date Presented 4/1/2017
This poster presents an fMRI study on the role of the action observation network in stroke recovery by examining brain activity differences after left hemisphere stroke and right hemisphere stroke. Our findings suggest that the side of stroke may impact responsiveness to treatment.
Primary Author and Speaker: Kaori L. Ito
Contributing Authors: Sook-Lei Liew, Kathleen Alice Garrison, Panthea Heydari, Mona Sobhani, Julie Werner, Hanna Damasio, Carolee Winstein, Lisa Aziz-Zadeh</jats:p
Methods—On the Reliability of the Electrochemical Data Recorded on Nickel Foam in Alkaline Solution: The Illusive Surface Oxide Layer
No full textInternational audienceThe extensive application of nickel foam (Ni foam) as current collector in supercapacitors has raised caveats on the contribution of the redox-active Ni foam to the measured capacities. However, due to the overlooked qualitative features (i.e., shapes) of the cyclic voltammograms (CVs), the redox reaction of the Ni foam oxide layer (NiFOL) has been frequently confused with the true electrochemical signature of the coated materials in alkaline solution. Herein, experimental CVs, scanning electron microscopy images, and estimations reveal that due to the high porosity of the Ni foam and its surface reactivity in alkaline solution (1–6 M KOH), the redox peak couple of the NiFOL can potentially be confused with or lead to misinterpretation of the true electrochemical features of the coatings. A classification of previous papers on a group of metal oxides investigated as battery-type or pseudocapacitive electrodes in the positive potential window is also presented to reveal the confusion between NiFOL and the coating when operated in alkaline solution
Intraday market dynamics
No full textThe revolutionary technological and regulatory changes in financial markets over the first few years of the new millennium have radically altered trading routines and strategies. Algorithms have taken over trade executions in an environment where interactions between virtual traders happen faster than blink of an eye. New trading strategies of long-term investors, e.g. institutional investors, have moved from one of submitting a few large orders to one of finely splitting orders over time and across trading venues in order to minimize their market impacts. Instead if human decisions, instructions that algorithms follow in order to locate liquidity, arbitrage opportunities, pattern detection, etc. determine the size and timing of transactions. As a result, individual transactions are far from reflecting economic decisions, and classical models of market microstructure may not be used to describe phenomena at transaction level.
I develop a novel aggregation approach that accounts for features modern markets; for a given stock, I identify successive sequences of transactions where cumulative dollar volume of each sequence is a fraction of previous month's market-capitalization plus a fixed dollar-amount. Time durations of these trade sequences measure trading activity, and the corresponding price changes reflect market impacts of a fixed dollar volume traded at variable intensities. With this approach I (a) control for the temporal dependence across individual transactions induced by dynamic order-splitting, (b) finely isolate different market conditions, e.g. volume spikes from low trading activity, (c) tell apart trading activity from trading volume, (d) reduce the effect of odd-lots bias that exists at transaction level, and (e) provide a measure of trading activity that helps us study intraday dynamics of trading activity and prices.
I first show that, for most stocks, price impacts of fixed dollar-positions significantly fall in trading activity. But price impacts and trading activity, on average, are endogenously determined: trading activity rises when liquidity (depth near good prices) is unusually high which presents itself as small price impacts. I then show that one can predict this variation using a simple instrument. Moreover, the relationships between price impacts (trading costs) and instrumented trading activity are very similar across differently-sized stocks post 2006, suggesting greater cross-stock homogeneity post RegNMS. In sharp contrast, greater {\it heterogeneity} obtains if one examines the levels of price impacts (trading costs): smaller (less liquid) stocks became less liquid post 2007, but the opposite holds for larger (more liquid) stocks. Using a CAMP that includes four Fama-French factors and key stock characteristics, I show that this divergence in liquidity is translated to greater liquidity premia post financial crisis. I findings indicate that the massive changes in the design of markets did not led to uniform improvements in stock liquidity and that the asymmetric evolution of liquidity across different stocks affected investment decisions.
I then begin to investigate the intraday dynamics of trading activity and price movements by contrasting two separate cases of changes in trading activity: I capture a relative increase in trading activity by a pair of successive trade sequences whose first sequences has a longer time durations---the opposite pattern reflects a decline in trading activity. I show that, surprisingly, increases in trading activity are associated with return momentum, but declines in trading activity are associated with price reversals. Return momentums are stronger when starting/concluding activity levels are higher and signed trades are less balanced. In sharp contrast, price reversals are stronger when starting/concluding activity levels are lower and signed trades are more balanced. I conclude that these patterns are liquidity driven, e.g. price reversals of falling activity reflects rewards to liquidity provision after a phase of high activity. I then document more interesting time of day patterns: while increases in trading activity are least likely in earlier trading hours, return momentum of rising activity is strongest at these times; similarly, while activity decrease are least likely near close price reversals of falling activity are strongest in later trading hours. These findings highlight the highly variable nature of trading over the course of trading day. Earlier hours witness execution of overnight trading decisions that raise trading activity and persistent price impacts. Later trading hours, however, feature lower competition to provide liquidity since traders target flat closing positions; thus greater rewards to liquidity provision in expected.
I conclude my work by trying to model the dynamic structure of trading activity in the form I measure it. I employ the ACD models of Engle and Russell (1998) that were designed to model the time durations between individual transactions (inter-transaction durations). In todays markets, however, individual transactions are hard to reconcile with economic behavior. Thus, estimates of ACD models or any other dynamic structure that utilized inter-transaction durations have limited economic interpretations. An important contributions of my work is to introduce an alternative input to ACD models that fit features of modern financial markets and can provide a basis for economic interpretations. Moreover, my approach indirectly addresses other computations and statistical challenges one would face dealing with inter-transaction durations. Performing stock-year specific estimates of ACD models, I identify several interesting routes for future research in the fields of empirical market microstructure and financial econometrics.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-08-01The student, Yashar Heydari Barardehi, accepted the attached license on 2015-05-28 at 20:32.The student, Yashar Heydari Barardehi, submitted this Dissertation for approval on 2015-05-28 at 20:37.This Dissertation was approved for publication on 2015-06-02 at 09:56.DSpace SAF Submission Ingestion Package generated from Vireo submission #8252 on 2015-09-29 at 14:58:28Made available in DSpace on 2015-09-29T20:49:27Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-06-02Embargo set by: Seth Robbins for item 89419
Lift date: 2017-09-29T20:50:34Z
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MicroGuard: Securing Bare-Metal Microcontrollers against Code-Reuse Attacks
No full textsponsorship: This research is supported by the research fund of KU Leuven and IMEC. The work of the third author has been partially supported by the EU H2020-SU-ICT-03-2018 Project No. 830929 CyberSec4Europe. We are grateful to Mahmoud Ammar, Hassaan Janjua, and Emad Heydari Beni for assisting us with their helpful comments and criticisms. (KU Leuven, IMEC, EU|830929)status: Published onlin
A Comparative Study on Tobacco Cessation Methods: A Quantitative Systematic Review
No full textBackground: During recent years, there have been many advances in different types of pharmacological and non-pharmacological tobacco control treatments. In this study, we aimed to identify the most effective smoking cessation methods used in quit based upon a review of the literature.
Methods: We did a search of PubMed, limited to English publications from 2000 to 2012. Two trained reviewers independently assessed titles, abstracts and full texts of articles after a pilot inter-rater reliability assessment which was conducted by the author (GH). The total number of papers and their conclusions including recommendation of that method (positive) or not supporting (negative) was computed for each method. The number of negative papers was subtracted from the number of positive ones for each method. In cases of inconsistency between the two reviewers, these were adjudicated by author.
Results: Of the 932 articles that were critically assessed, 780 studies supported quit smoking methods. In 90 studies, the methods were not supported or rejected and in 62 cases the methods were not supported. Nicotine replacement therapy (NRT), Champix and Zyban with 352, 117 and 71 studies respectively were the most supported methods and e-cigarettes and non-Nicotine medications with one case were the least supported methods. Finally, NRT with 39 and Champix and education with 36 scores were the most supported methods.
Conclusions: Results of this review indicate that the scientific papers in the most recent decade recommend the use of NRT and Champix in combination with educational interventions. Additional research is needed to compare qualitative and quantitative studies for smoking cessation
Collaborative gym: A simulation benchmark for multi-robotic tasks
No full textThe design of multi-robot systems has gained increasing attention in recent years. The field of cooperative Multi-Agent Robot Systems (MARS) has shown the potential to provide reliable and cost-effective solutions to a wide range of automated applications. Communication and coordination between autonomous agents require robust and intelligent control systems in order to achieve high-quality performance. This paper presents Collaborative Gym, an open-source, physics-based simulation framework for multi-robot interaction. This simulation environment differs from existing robotic simulation environments in that it is designed to model the interaction between multiple robots. Despite the presence of a large number of single robotic environments, multi-robotic simulation environments for reinforcement learning are rare. Collaborative Gym contains four simulated tasks in which different commercial robots work in collaboration: poking, lifting, balancing, and passing. For each of the four tasks, baseline policies are presented for various combinations of commercial robots which have been trained using reinforcement learning. The study demonstrated that Collaborative Gym is a promising open-source framework for the development of multi-robotic collaborative robotic tasks.https://github.com/gabriansa/collaborative-gymMechanical Engineering | Multi-Machine Engineerin
The Morphological Analysis of Houd (PBUH) Tale in the Translation of Tabariâs Commentary
No full textShowing the possible connections between Quranic texts and new scientific approaches in the today world is amongst the most important missions of Muslim scholars. This paper follows the same mission and the author studies the tale of Houd (PBUH) in the translation of Tabari’s commentary based on morphological theory of Vladimir Propp. The number of characters and their functions as well as the plot resulted from the sequence of functions in this story have close relationship with Propp’s theory. Regarding fictional movements, a new movement is seen in this story which is absent in Propp’s models and has fundamental differences with them. The theory of Propp originates from the study of Russian folk tales and its application for investigating religious tales is not without problems but since this theory pays attention to the structures not instances, it is very useful for studying religious tales. Finally, the author suggests that Iranian scholars should provide morphological analysis of other Quranic tales till the final structure of Quranic texts is obtained via comparing such analyses
Analysis of a Substrate Integrated Waveguide Hybrid Ring (Rat-Race) Coupler
No full textThis paper presents an efficient analysis of a substrate integrated waveguide (SIW) single-layer hybrid ring coupler (rat-race) for millimeter-wave and microwave applications. The scattered field from each circular cylinder is expanded by cylindrical eigenfunctions with unknown coefficients that have been solved by electric and magnetic tangential boundary on each metallic via. The coupler S-matrix is calculated by using mode matching that uses the cylindrical vector expansion analysis to minimize the computational time and provides more physical insight. To achieve higher bandwidth, the radiuses of the coupler under analysis have been optimized in Matlab code by invasive weed optimization (IWO) method, and the results have been verified by CST package. The return loss and the isolation are less than −15 dB, and −18 dB, respectively. The insertion loss is divided equally -3±0.2 dB, with 0±5 and 180±10 degrees in output ports over the operating frequency bandwidth and the agreement of phase differences in output ports has been examined objectively by feature selective validation (FSV) technique
Application of Modified Multi-Walled Carbon Nanotubes in Removal of Zinc and Nickel from Effluent (Case Study: Effluent of Tarom Industrial Town of Zanjan)
No full textWastewaters containing heavy metals produced by industries has detrimental effects on the environment. One of the effective methods for removal of heavy metals is the use of adsorption method by nanoparticles. The aim of this study was to remove zinc and nickel elements from effluents of Tarom industrial Town of Zanjan using modified multi-walled carbon nanotubes. In this descriptive-analytical study, effect of effective parameters such as contact time, adsorbent content, pH, temperature and concentration of metal ions on the removal efficiency of metals from Ni(II) and Zn(II) from wastewater and isotherm, kinetics and thermodynamic models of adsorption process was investigated. SEM and FTIR spectrums were taken to prove nanotubes and to determine adsorbent factor groups before and after preparation, respectively. The results of study showed that the absorption of Zn and Ni metals is highly dependent on pH. Study results showed that by increasing the pH of effluent up to the range of 8, and 7 for Ni(II) and Zn(II) metals, respectively, the removal percentage of metal ions increased and then decreased. By increasing in the adsorbent amount and contact time, the removal percentage of metal ions increased and by increasing the reaction temperature and concentration of metal ions in the effluent, the removal percentage of metal ions decreased. So that, the highest removal percentage of Ni(II) and Zn(II) ions was obtained in adsorbent value of 2 mg/L, contact time of 120 min, concentration of 100 mg/L and temperature of 15 °C. The results also showed that the adsorption of Ni(II) and Zn(II) metals from effluent follows Langmir isotherm absorption model and the adsorption kinetics is adapted to the second-order pseudo-reaction (R2>0.98), this mechanism is controlled by adsorption. Also, based on the obtained results, with increasing temperature, the free energy of Gibbs system standard decreased, which indicates the adsorption process is done spontaneously. The maximum adsorption capacity of nickel and zinc metals was 43 and 54 mg/g, respectively. According to the results, it is concluded that modified multi-walled carbon nanotubes have good ability to remove nickel and zinc from effluents and can be used in wastewater treatment containing heavy metals
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