Synthetic Radar Dataset Generator for Macro-Gesture Recognition

Recent developments in mmWave technology allow the detection and classification of dynamic arm gestures. However, achieving a high accuracy and generalization requires a lot of samples for the training of a machine learning model. Furthermore, in order to capture variability in the gesture class, the participation of many subjects and the conduct of many gestures with different arm speed are required. In case of macro-gestures, the position of the subject must also vary inside the field of view of the device. This would require a significant amount of time and effort, which needs to be repeated in case that the sensor hardware or the modulation parameters are modified. In order to reduce the required manual effort, here we developed a synthetic data generator that is capable of simulating seven arm gestures by utilizing Blender, an open-source 3D creation suite. We used it to generate 600 artificial samples with varying speed of execution and relative position of the simulated subject, and used them to train a machine learning model. We tested the model using a real dataset recorded from ten subjects, using an experimental sensor. The test set yielded 84.2% accuracy, indicating that synthetic data generation can significantly contribute in the pre-training of a model

A Ground-Based Albedo Upper Limit for HD 189733b from Polarimetry

We present 50 nights of polarimetric observations of HD 189733 in $B$ band using the POLISH2 aperture-integrated polarimeter at the Lick Observatory Shane 3-m telescope. This instrument, commissioned in 2011, is designed to search for Rayleigh scattering from short-period exoplanets due to the polarized nature of scattered light. Since these planets are spatially unresolvable from their host stars, the relative contribution of the planet-to-total system polarization is expected to vary with an amplitude of order 10 parts per million (ppm) over the course of the orbit. Non-zero and also variable at the 10 ppm level, the inherent polarization of the Lick 3-m telescope limits the accuracy of our measurements and currently inhibits conclusive detection of scattered light from this exoplanet. However, the amplitude of observed variability conservatively sets a $3 \sigma$ upper limit to the planet-induced polarization of the system of 58 ppm in $B$ band, which is consistent with a previous upper limit from the POLISH instrument at the Palomar Observatory 5-m telescope (Wiktorowicz 2009). A physically-motivated Rayleigh scattering model, which includes the depolarizing effects of multiple scattering, is used to conservatively set a $3 \sigma$ upper limit to the geometric albedo of HD 189733b of $A_g < 0.37$. This value is consistent with the value $A_g = 0.226 \pm 0.091$ derived from occultation observations with HST STIS (Evans et al. 2013), but it is inconsistent with the large $A_g = 0.61 \pm 0.12$ albedo reported by (Berdyugina et al. 2011).Comment: 10 pages, 9 figures, submitted to Ap

Short-term postoperative outcomes after liver resection in the elderly patient:a nationwide population-based study

BACKGROUND: Liver resection is high-risk surgery in particular in elderly patients. The aim of this study was to explore postoperative outcomes after liver resection in elderly patients. METHODS: In this nationwide study, all patients who underwent liver resection for primary and secondary liver tumours in the Netherlands between 2014 and 2019 were included. Age groups were composed as younger than 70 (70-), between 70 and 80 (septuagenarians), and 80 years or older (octogenarians). Proportion of liver resections per age group and 30-day major morbidity and 30-day mortality were assessed. RESULTS: In total, 6587 patients were included of whom 4023 (58.9%) were younger than 70, 2135 (32.4%) were septuagenarians and 429 (6.5%) were octogenarians. The proportion of septuagenarians increased during the study period (aOR:1.06, CI:1.02-1.09, p < 0.001). Thirty-day major morbidity was higher in septuagenarians (11%) and octogenarians (12%) compared to younger patients (9%, p = 0.049). Thirty-day mortality was higher in septuagenarians (4%) and octogenarians (4%) compared to younger patients (2%, p < 0.001). Cardiopulmonary complications occurred more frequently with higher age, liver-specific complications did not. Higher age was associated with higher 30-day morbidity and 30-day mortality in multivariable logistic regression. CONCLUSION: Thirty-day major morbidity and 30-day mortality are higher after liver resection in elderly patients, attributed mainly to non-surgical cardiopulmonary complications

Nationwide oncological networks for resection of colorectal liver metastases in the Netherlands:Differences and postoperative outcomes

INTRODUCTION: Widespread differences in patient demographics and disease burden between hospitals for resection of colorectal liver metastases (CRLM) have been described. In the Netherlands, networks consisting of at least one tertiary referral centre and several regional hospitals have been established to optimize treatment and outcomes. The aim of this study was to assess variation in case-mix, and outcomes between these networks. METHODS: This was a population-based study including all patients who underwent CRLM resection in the Netherlands between 2014 and 2019. Variation in case-mix and outcomes between seven networks covering the whole country was evaluated. Differences in case-mix, expected 30-day major morbidity (Clavien-Dindo ≥3a) and 30-day mortality between networks were assessed. RESULTS: In total 5383 patients were included. Thirty-day major morbidity was 5.7% and 30-day mortality was 1.5%. Significant differences between networks were observed for Charlson Comorbidity Index, ASA 3+, previous liver resection, liver disease, preoperative MRI, preoperative chemotherapy, ≥3 CRLM, diameter of largest CRLM ≥55 mm, major resection, combined resection and ablation, rectal primary tumour, bilobar and extrahepatic disease. Uncorrected 30-day major morbidity ranged between 3.3% and 13.1% for hospitals, 30-day mortality ranged between 0.0% and 4.5%. Uncorrected 30-day major morbidity ranged between 4.4% and 6.0% for networks, 30-day mortality ranged between 0.0% and 2.5%. No negative outliers were observed after case-mix correction. CONCLUSION: Variation in case-mix and outcomes are considerably smaller on a network level as compared to a hospital level. Therefore, auditing is more meaningful at a network level and collaboration of hospitals within networks should be pursued

Anatomical Versus Nonanatomical Resection of Colorectal Liver Metastases: Is There a Difference in Surgical and Oncological Outcome?

Background: The increased use of neoadjuvant chemotherapy and minimally invasive therapies for recurrence in patients with colorectal liver metastases (CLM) makes a surgical strategy

Benign Ancient Schwannoma of the abdominal wall: An unwanted birthday present

<p>Abstract</p> <p>Background</p> <p>There has been a recent growth in the use of whole body Computerised Tomography (CT) scans in the private sector as a screening test for asymptomatic disease. This is despite scant evidence to show any positive effect on morbidity or mortality. There has been concern raised over the possible harms of the test in terms of radiation exposure as well as the risk and anxiety of further investigation and treatment for the large numbers of benign lesions identified.</p> <p>Case Presentation</p> <p>A healthy 64 year old lady received a privately funded whole body CT scan for her birthday which revealed an incidental mass in the right iliac fossa. This was investigated with further imaging and colonoscopy and as confident diagnosis could not be made, eventually excised. Histology demonstrated this to be a benign ancient schwannoma and we believe this to be the first reported case of an abdominal wall schwannoma in the English literature</p> <p>Conclusions</p> <p>Ancient schwannomas are rare tumours of the peripheral nerve sheaths more usually found in the head, neck and flexor surfaces of extremities. They are a subtype of classical schwannomas with a predominance of degenerative changes. Our case highlights the pitfalls of such screening tests in demonstrating benign disease and subjecting patients to what turns out to be unnecessary invasive investigation and treatment. It provides evidence as to the consequences of the large number of false positive results that are created by blind CT scanning of asymptomatic patients i.e. its tendency to detect pseudodiesease rather than affect survival rates. Should the number of scans increase there may be an unnecessary burden on NHS resources due to the large numbers of benign lesions picked up, that are then referred for further investigation.</p

Outcome of Microscopic Incomplete Resection (R1) of Colorectal Liver Metastases in the Era of Neoadjuvant Chemotherapy

Background: Data from patients with colorectal liver metastases (CRLM) who received neoadjuvant chemotherapy before resection were reviewed and evaluated to see whether neoadjuvant chemotherapy influences the predictive outcome of R1 resections (margin is 0 mm) in patients with CRLM. Methods: Between January 2000 and December 2008, all consecutive patients undergoing liver resection for CRLM were analyzed. Patients were divided into those who did and did not receive neoadjuvant chemotherapy. The outcome after R0 (tumor-free margin >0 mm) and R1 (tumor-free margin 0 mm) resection was compared. Results: A total of 264 were eligible for analysis. Median follow-up was 34 months. Patients without chemotherapy showed a significant difference in median disease-free survival (DFS) after R0 or R1 resection: 17 [95% confidence interval (CI) 10-24] months versus 8 (95% CI 4-12) months (P < 0.001), whereas in

Neo-adjuvant chemotherapy followed by surgery versus surgery alone in high-risk patients with resectable colorectal liver metastases: The CHARISMA randomized multicenter clinical trial

Background: Efforts to improve the outcome of liver surgery by combining curative resection with chemotherapy have failed to demonstrate de

Experimental Identification of Dynamic Parameters' Robotic Arm

92 σ.Οι βιομηχανικοί βραχίονες έχουν γίνει ένα απαραίτητο μέσο αυτοματισμού για την αύξηση της ευελι- ξίας και της παραγωγικότητας. Τα αυξανόμενα πρότυπα ποιότητας και οι νέες εφαρμογές επιβάλλουν αυστηρότερες απαιτήσεις για ακρίβεια, αξιοπιστία και απόδοση. Λόγω της πολύπλοκης μη γραμμικής δυναμικής των ρομπότ, η σχεδίαση του ελέγχου πρέπει να περιλαμβάνει ακριβή δυναμικά ρομποτικά μοντέλα. Η πειραματική αναγνώριση των άγνωστων παραμέτρων αδράνειας είναι μια διαδικασία για την εκτίμηση τέτοιων μοντέλων χρησιμοποιώντας δεδομένα κίνησης κατά την διάρκεια καλά σχεδια- σμένων πειραμάτων. Η πειραματική αναγνώριση του ρομποτικού χειριστή είναι ο μόνος αποτελεσματικός τρόπος για την εύρεση δυναμικών μοντέλων ικανών να χρησιμοποιηθούν για τον έλεγχο του βραχίονα. Οι πληρο- φορίες που προσφέρουν οι εταιρείες παραγωγής των ρομπότ συνήθως είναι ανεπαρκείς ή ανακριβείς, ειδικά για θέματα όπως η τριβή και τα χαρακτηριστικά της σύζευξης των αξόνων. Η άμεση μέτρηση των φυσικών παραμέτρων δεν είναι ρεαλιστική λόγω της πολυπλοκότητας των εξαρτημάτων. Στην παρούσα εργασία ακολουθείται το βασικό πρότυπο της αναγνώρισης των ρομποτικών παρα- μέτρων όπως υπάρχει στην βιβλιογραφία, όμως σε κάθε βήμα εφαρμόζονται οι διαφορετικές τεχνικές που βρέθηκαν.Το ρομπότ που χρησιμοποιήθηκε είναι το Katana 450 και το λογισμικό διασύνδεσης είναι το ROS Fuerte. Πολύ σημαντική είναι η εύρεση βέλτιστων τροχιών διέγερσης που θα μπορούν να διεγείρουν επαρκώς το βραχίονα, αυτό έγινε χρησιμοποιώντας το Global Optimization Toolbox του Matlab. Κατά την διάρκεια του πειράματος αναγνώρισης απαραίτητη είναι η απόκτηση δεδομέ- νων για την γωνία και την ροπή των αξόνων, για αυτό έγιναν μερικές τροποποιήσεις στο λογισμικό. Χρησιμοποιώντας την μέθοδο των ελαχίστων τετραγώνων υπολογίζεται το άγνωστο σετ παραμέτρων καθώς και η τυπική τους απόκλιση. Με το πείραμα της επαλήθευσης υπολογίζεται το σφάλμα πρόβλε- ψης της ροπής για μία νέα τροχιά, συγκρίνοντας διαφορετικές τεχνικές που βρέθηκαν και επιλέγεται ο καλύτερος δυνατός συνδυασμός. Σε μελλοντική εργασία τα υπάρχοντα αποτελέσματα θα μπορούσαν να χρησιμοποιηθούν για τον έλεγχο του βραχίονα, δοκιμάζοντας αλγορίθμους adaptive control υπό την προϋπόθεση αναβάθμισης του.The industrial manipulators have become an indispensable tool of automation for increased flexibility and productivity. The increasing quality standards and new applications impose stricter requirements for precision, reliability and performance. Due to the complex nonlinear dynamics of the robot, the control design must include an accurate dynamic robot model. The robotic identification is a technique to estimate such models by collecting data during well-designed experiments. Experimental robot identification is the only efficient way to obtain accurate robot models. Information provided by robot manufacturers is usually insufficient or inaccurate, especially those dealing with friction and compliance characteristics. Direct measurement of the physical parameters is unrealistic because of the complexity of most robots. The present study followed the basic pattern of experimental robot identification as it exists in the literature, but in every step a variety of different techniques are applied. The robot used is the Katana 450 and the software interface is the ROS Fuerte. A very important issue is to find optimal trajectories that can excite the robotic arm, this was done by using the Global Optimization Toolbox of Matlab. During the experiment it is necessary to obtain data on the torque and angle of the axes and some modifications on the software had to be made. Using the method of least squares, a set of unknown dynamic parameters was found. The experiment of verification was used to calculate the prediction error of torque, comparing different techniques found in literature and selecting the best possible combination. In future work the existing results could be used to control the arm, testing algorithms of adaptive control, if an upgrade of the controller is completed.Αλέξανδρος Α. Νίνο