Learning Human-Robot Collaboration Insights through the Integration of Muscle Activity in Interaction Motion Models

Recent progress in human-robot collaboration makes fast and fluid interactions possible, even when human observations are partial and occluded. Methods like Interaction Probabilistic Movement Primitives (ProMP) model human trajectories through motion capture systems. However, such representation does not properly model tasks where similar motions handle different objects. Under current approaches, a robot would not adapt its pose and dynamics for proper handling. We integrate the use of Electromyography (EMG) into the Interaction ProMP framework and utilize muscular signals to augment the human observation representation. The contribution of our paper is increased task discernment when trajectories are similar but tools are different and require the robot to adjust its pose for proper handling. Interaction ProMPs are used with an augmented vector that integrates muscle activity. Augmented time-normalized trajectories are used in training to learn correlation parameters and robot motions are predicted by finding the best weight combination and temporal scaling for a task. Collaborative single task scenarios with similar motions but different objects were used and compared. For one experiment only joint angles were recorded, for the other EMG signals were additionally integrated. Task recognition was computed for both tasks. Observation state vectors with augmented EMG signals were able to completely identify differences across tasks, while the baseline method failed every time. Integrating EMG signals into collaborative tasks significantly increases the ability of the system to recognize nuances in the tasks that are otherwise imperceptible, up to 74.6% in our studies. Furthermore, the integration of EMG signals for collaboration also opens the door to a wide class of human-robot physical interactions based on haptic communication that has been largely unexploited in the field.Comment: 7 pages, 2 figures, 2 tables. As submitted to Humanoids 201

Convergence theorems for implicit iteration process for a finite family of continuous pseudocontractive mappings

AbstractIn this paper, a necessary and sufficient conditions for the strong convergence to a common fixed point of a finite family of continuous pseudocontractive mappings are proved in an arbitrary real Banach space using an implicit iteration scheme recently introduced by Xu and Ori [H.K. Xu, R.G. Ori, An implicit iteration process for nonexpansive mappings, Numer. Fuct. Anal. Optim. 22 (2001) 767–773] in condition αn∈(0,1], and also strong and weak convergence theorem of a finite family of strictly pseudocontractive mappings of Browder–Petryshyn type is obtained. The results presented extend and improve the corresponding results of M.O. Osilike [M.O. Osilike, Implicit iteration process for common fixed points of a finite family of strictly pseudocontractive maps, J. Math. Anal. Appl. 294 (2004) 73–81]

Rapid screening of antibiotics in foods by HPTLC-FLD/EDA/MS

Nowadays, the usage and partly abuse of veterinary antibiotics resulted in a very pressing need to control residues in foods of animal origin. Particularly, the increasingly demanding MRL issues and the huge number of samples to be monitored raised great challenges in this field. Microbial growth inhibition assays are traditionally employed for screening purposes, while sophisticated HPLC-MS methods are alternatively used or only used for confirmation purposes. To substitute the time consuming growth inhibition assays, HPTLC as a platform hyphenated to multi detection modes was employed in this study for the development of a high throughput, sensitive and cost-efficient screening-oriented methodology for antibiotics residues. The first step was focused on tetracyclines and fluoroquinolones, which are the most problematic antibiotics in the European Union and account for the most of the used veterinary antibiotics. To prevent strong tailing effects, the separation was optimized on normal-phase silica gel plates modified with ethylenediamine tetraacetic acid (EDTA). Besides, selective and sensitive fluorescence densitometry was optimized to achieve best signal/noise ratios. Under these conditions, limits of detection (LODs) and quantitation (LOQs) were in the range 1225 and 4595 µg/kg, respectively. Recoveries from milk samples, spiked at 50, 100 and 150 µg/kg and extracted by a modified QuEChERS procedure, ranged from 76 to 105%. To circumvent the ion suppressions due to EDTA, HPTLC-mass spectrometry (HPTLC-MS) was optimized, allowing the selective confirmation of positive findings, also offering high sensitivity of 25 µg/kg, and meeting Commission Regulation (EU) No. 37/2010. In the second step, sulfonamides were targeted, which are the secondly most administered veterinary antibiotics in the European Union. Separation of twelve most important sulfonamides was achieved on HPTLC silica gel plates, followed by fluram derivatization and sensitive and selective quantitation by fluorescent densitometry. LODs and LOQs were determined to 1540 and 3570 µg/kg, respectively. Samples of bovine milk, porcine liver and kidney were extracted according to the QuEChERS strategy. Additionally, a confirmative detection by HPTLC-MS was optimized, offering straightforward identification of target zones. The method was validated to meet the enforced Commission Regulation (EU) No. 37/2010. Finally, a more universal screening method based on HPTLC-bioautography was developed for most of the first-line veterinary antibiotics. A comprehensive HPTLC plate test revealed that the bio-compatibility of different plate layer materials to the applied bioluminescent bacteria (A. fischeri DSM No. 7151) was surprisingly different. It was then discovered that both bright bioluminescent background and significant inhibition zones of antibiotics can only be achieved on HPTLC amino F254S plates. In this case, HPTLC was not used for the chromatographic separation of individual antibiotics extracted with acetonitrile, but in terms of planar solid phase extraction to separate bioactive matrix compounds and to focus the analytes within two distinct target zones of different polarity. Together with HPTLC-MS for identification and confirmation purposes, the developed procedure enabled the rapid, sensitive and efficient multi-class screening of antibiotic residues (16 species of 5 groups, except sulfonamides and penicillins, which only affect Gram positive bacteria). The multi-sample plate images provided the results within a few hours. Thanks to the high sensitivity and the great matrix tolerance, the established method was successfully applied to bovine milk and porcine kidney samples, each spiked at the EU MLRs.Der enorme Einsatz und partielle Missbrauch von Antibiotika in der Tiermedizin führte zu dringend notwendigen Maßnahmen, um Rückstände in tierischen Lebensmitteln zu kontrollieren. Insbesondere die steigend anspruchsvollen Rückstandshöchstgehalte sowie die geforderten zunehmenden Probenzahlen stellen eine große Herausforderung dar. Mikrobielle Hemmhof-Assays werden traditionell zum Proben-Screening eingesetzt, während anspruchsvolle HPLC-MS Methoden häufig alternativ oder nur zur Absicherung positiver Befunde verwendet werden. Um die zeitintensiven Hemmhof-Assays zu ersetzen, wurde in dieser Arbeit die HPTLC gekoppelt mit Multi-Detektionsmethoden eingesetzt, um eine schnelle und kostengünstige Screening-orientierte Methodik für Antibiotika-Rückstände zu entwickeln. Der erste Teil der Arbeit konzentrierte sich auf zwei Gruppen von "schwierigen" Antibiotika, Tetracycline und Fluorchinolone, die zu den häufigst eingesetzten veterinärmedizinischen Antibiotika gehören. Unter Vermeidung von Tailing-Effekten wurde die HPTLC-Trennung auf Normalphasen-Kieselgelplatten, modifiziert mit Ethylendiamintetraessigsäure (EDTA), optimiert. Außerdem wurde eine selektive und empfindliche Fluoreszenz-Densitometrie genutzt, um beste Signal/Rausch-Verhältnisse zu erreichen. Nachweis- und Bestimmungsgrenzen lagen im Bereich von 12-25 und 45-95 µg/kg. Wiederfindungen aus Milchproben, dotiert auf 50, 100 und 150 µg/kg und extrahiert mit einer modifizierten QuEChERS-Methode, ergaben sich zu 76-105%. Zur Absicherung positiver Befunde wurde die Massenspektrometrie (HPTLC-MS) bezüglich Ionensuppressionen durch EDTA dahingehend optimiert, dass eine empfindliche Detektion von 25 µg/kg möglich war und die Vorgaben der Verordnung (EU) Nr. 37/2010 erfüllt wurden. Im zweiten Schritt galt das Interesse den Sulfonamiden, den zweithäufigst eingesetzten veterinärmedizinischen Antibiotika. Die Trennung erfolgte auf HPTLC-Kieselgelschichten und nachfolgender Fluram-Derivatisierung. Dies erlaubte eine selektive und sehr sensitive Quantifizierung der zwölf bedeutendsten Sulfonamide durch Fluoreszenz-Densitometrie. Nachweis- und Bestimmungsgrenzen ergaben sich zu 15-40 und 35-70 µg/kg. Die Extraktion von Milch-, Leber- und Nierenproben erfolgte mit Acetonitril (analog "QuEChERS"). Zur Bestätigung positiver Proben wurde erneut die HPTLC-MS Kopplung zur einfachen Identifizierung der Zielzonen optimiert. Die Methode wurde hinsichtlich der Vorgaben der Verordnung (EU) Nr. 37/2010 für Milch sowie Schweine-Leber und -Nieren validiert. Schließlich wurde eine universelle Screening-Methode mittels HPTLC-Bioautographie für die meisten der First-Line Tier-Antibiotika entwickelt. Ein umfangreicher HPTLC-Plattentest zeigte, dass die Bio-Kompatibilität der verschiedenen Schichtmaterialien mit den eingesetzten Leuchtbakterien (Aliivibrio fischeri DSM-Nr. 7151) überraschend unterschiedlich war. Nur auf HPTLC-Amino F254S Platten zeigten die Bakterien die optimale Biolumineszenz und damit signifikante Hemmzonen für Antibiotika. Nach Extraktion mit Acetonitril wurde die HPTLC hier nicht zur Auftrennung der einzelnen Antibiotika optimiert, sondern im Sinne einer planaren Festphasenextraktion zur Abtrennung ebenfalls bioaktiver Matrixkomponenten und zur Fokussierung der Antibiotika in zwei unterschiedlich polare Zielzonen. Zusammen mit der HPTLC-MS Kopplung lieferte diese Methode ein schnelles, empfindliches und effizientes Multi-Class-Screening von Antibiotika-Rückständen (16 Wirkstoffe aus 5 Gruppen, außer Sulfonamide und Penicilline, welche nur Gram-positive Bakterien hemmen). Ein Plattenbild lieferte innerhalb weniger Stunden das Ergebnis für viele Proben. Dank hoher Empfindlichkeit und großer Matrixtoleranz wurde die Methode erfolgreich auf Milch- und Schweinenieren-Proben angewendet, dotiert auf die EU-Rückstandshöchstgehalte

Age Differences in Stress and Coping: Problem-Focused Strategies Mediate the Relationship between Age and Positive Affect

The present study examined the different types of stressors experienced by adults of different ages, their coping strategies, and positive/negative affect. A mediation hypothesis of coping strategies was tested on the relationships between age and positive/negative affect. One-hundred and ninety-six community-dwelling adults (age range 18-89 years old) reported the most stressful situation they experienced in the past month and coping strategies. Levels of positive and negative affect in the past month were also measured. Content analysis revealed age differences in different types of stressors adults reported. Three types of coping strategies were found: problem-focused, positive emotion-focused, and negative emotion-focused coping. Older adults were less likely than younger adults to use problem-focused coping and reported lower levels of positive affect. Path analysis supported the mediation hypothesis, showing that problem-focused coping mediated the relationship between age and positive affect. Implications are discussed on the importance of promoting problem-focused coping among older adults