Inverse reinforcement learning to control a robotic arm using a Brain-Computer Interface

The goal of this project is to use inverse reinforce- ment learning to better control a JACO robotic arm developed by Kinova in a Brain-Computer Interface (BCI). A self-paced BCI such as a motor imagery based-BCI allows the subject to give orders at any time to freely control a device. But using this paradigm, even after a long training, the accuracy of the classifier used to recognize the order is not 100%. While a lot of studies try to improve the accuracy using a preprocessing stage that improves the feature extraction, we work on a post- processing solution. The classifier used to recognize the mental commands will provide as outputs a value for each command such as the posterior probability. But the executed action will not only depend on this information. A decision process will also take into account the position of the robotic arm and previous trajectories. More precisely, the decision process will be obtained applying an inverse reinforcement learning (IRL) on a subset of trajectories specified by an expert. At the end of the workshop, the convergence of the inverse reinforcement algorithm has not been achieved. Nevertheless, we developed a whole processing chain based on OpenViBE for controlling 2D- movements and we present how to deal with this high dimensional time series problem with a lot of noise which is unusual for the IRL community

Synthesis, Structure and Bonding Analysis of the Zwitterionic PPP-Pincer Complex (6-Ph2P-Ace-5-)2P(O)AuCl2

The reaction of (6-Ph2P-Ace-5-)2P(O)H with (tht)AuCl3proceeds via elimination oftetrahydrothiophene (tht) and HCl, providing the zwitterionic PPP-pincer complex (6-Ph2P-Ace-5-)2P(O)AuCl2(1) as yellow crystals. The molecular structure of1was established and studied by X-raycrystallography. The electronic structure was computationally analyzed using a comprehensiveset of real-space bonding indicators derived from electron and electron-pair densities, providinginsight into the relative contributions of covalent and non-covalent forces to the polar-covalent Au–Cl,Au–P, and P–O−bonds; the latter being one of the textbook cases for strongly polarized covalentinteractions. Partial spatial complementarity between both bonding aspects is suggested by theelectronic properties of the distinctively different Au–Cl bonds

Development of an active foot orthosis

Current prostheses (and orthoses) available on the market are functional, but are mostly based on passive mechanisms. Consequently, the patients generally develop various strategies which generate reduced locomotion speed, a non-natural gait and considerable fatigue. Active prostheses solve these problems partially: powered by a battery-operated motor, they move on their own and therefore reduce the fatigue of the amputees while improving their posture. The TCTS lab is developing a special interface for such systems, in order to include the patient's intent in the algorithms controlling the prosthesis actuators. In this poster, we present a review of the different strategies involved

Forecast reconciliation for vaccine supply chain optimization

Vaccine supply chain optimization can benefit from hierarchical time series forecasting, when grouping the vaccines by type or location. However, forecasts of different hierarchy levels become incoherent when higher levels do not match the sum of the lower levels forecasts, which can be addressed by reconciliation methods. In this paper, we tackle the vaccine sale forecasting problem by modeling sales data from GSK between 2010 and 2021 as a hierarchical time series. After forecasting future values with several ARIMA models, we systematically compare the performance of various reconciliation methods, using statistical tests. We also compare the performance of the forecast before and after COVID. The results highlight Minimum Trace and Weighted Least Squares with Structural scaling as the best performing methods, which provided a coherent forecast while reducing the forecast error of the baseline ARIMA

Bacteria Hunt: Evaluating multi-paradigm BCI interaction

The multimodal, multi-paradigm brain-computer interfacing (BCI) game Bacteria Hunt was used to evaluate two aspects of BCI interaction in a gaming context. One goal was to examine the effect of feedback on the ability of the user to manipulate his mental state of relaxation. This was done by having one condition in which the subject played the game with real feedback, and another with sham feedback. The feedback did not seem to affect the game experience (such as sense of control and tension) or the objective indicators of relaxation, alpha activity and heart rate. The results are discussed with regard to clinical neurofeedback studies. The second goal was to look into possible interactions between the two BCI paradigms used in the game: steady-state visually-evoked potentials (SSVEP) as an indicator of concentration, and alpha activity as a measure of relaxation. SSVEP stimulation activates the cortex and can thus block the alpha rhythm. Despite this effect, subjects were able to keep their alpha power up, in compliance with the instructed relaxation task. In addition to the main goals, a new SSVEP detection algorithm was developed and evaluated

Emission color-tunable oxazol(in)yl-substituted excited-state intramolecular proton transfer (ESIPT)-based luminophores

Oxazolinyl- and arylchalcogenazolyl-substituted hydroxyfluorenes exhibiting excited-state intramolecular proton transfer (ESIPT) are described as potent and highly modular luminophores. Emission color tuning was achieved by varying the π-expansion and the insertion of different chalcogen atoms

Kinetic Stabilization of Heavier Bis(m-terphenyl)pnictogen Phosphaethynolates

Kinetic stabilization using bulky m-terphenyl substituents is the key to the isolation of the diarylantimony and diarylbismuth phosphaethynolates (2,6-Mes2C6H3)2EPCO and the related N-heterocyclic carbene complexes (2,6-Mes2C6H3)2EP(O)C(IMe4) (E=Sb, Bi; IMe4=1,3,4,5-tetramethylimidazol-2-ylidene), which have been fully characterized crystallographically and spectroscopically. The experimental characterization was augmented by a DFT based real space bond indicator analysis of the electron density, including AIM, NCI, and ELI-D methods

Lewis Superacidic Divalent Bis( m ‐terphenyl)element Cations [(2,6‐Mes 2 C 6 H 3 ) 2 E] + of Group 13 Revisited and Extended (E=B, Al, Ga, In, Tl)

In a combined experimental and computational study, the molecular and electronic structures of the divalent bis(m- terphenyl)element cations [(2,6-Mes2C6H3)2E]+ of group 13 (1, E=B; 2, E=Al; 3, E=Ga; 4, E=In; 5, E=Tl) were investigated. The preparation and characterization of 2, 3 and 5 were previously reported by Wehmschulte’s (Organometallics 2004, 23, 1965– 1967; J. Am. Chem. Soc. 2003, 125, 1470–1471) and our groups (Organometallics 2009, 28, 6893–6901). The indinium ion 4 was prepared and fully characterized for the first time. Attempts to prepare the borinium ion 1 by fluoride or hydride abstraction were unsuccessful. The electronic structures of 1–5 and the stabilization by the bulky m-terphenyl substituents were analyzed using quantum chemical calculations and compared to the divalent bis(m-terphenyl)pnictogenium ions [(2,6- Mes2C6H3)2E]+ of group 15 (6, E=P; 7, E=As; 8, E=Sb; 9, E=Bi) previously investigated by our group (Angew. Chem. Int. Ed. 2018, 57, 10080–10084). The calculated fluoride ion affinities (FIA) of 1–9 are higher than that of SbF5, which classifies them as Lewis superacids