Search

Your search keyword '"Dosen, Strahinja"' showing total 243 results
Start Over Author "Dosen, Strahinja" Search Limiters Available in Library Collection
243 results on '"Dosen, Strahinja"'

3. Semi-autonomous Prosthesis Control Using Minimal Depth Information and Vibrotactile Feedback

Author

Castro, Miguel Nobre and Dosen, Strahinja

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Robotics
Abstract

A semi-autonomous prosthesis control based on computer vision can be used to improve performance while decreasing the cognitive burden, especially when using advanced systems with multiple functions. However, a drawback of this approach is that it relies on the complex processing of a significant amount of data (e.g., a point cloud provided by a depth sensor), which can be a challenge when deploying such a system onto an embedded prosthesis controller. In the present study, therefore, we propose a novel method to reconstruct the shape of the target object using minimal data. Specifically, four concurrent laser scanner lines provide partial contours of the object cross-section. Simple geometry is then used to reconstruct the dimensions and orientation of spherical, cylindrical and cuboid objects. The prototype system was implemented using depth sensor to simulate the scan lines and vibrotactile feedback to aid the user during aiming of the laser towards the target object. The prototype was tested on ten able-bodied volunteers who used the semi-autonomous prosthesis to grasp a set of ten objects of different shape, size and orientation. The novel prototype was compared against the benchmark system, which used the full depth data. The results showed that novel system could be used to successfully handle all the objects, and that the performance improved with training, although it was still somewhat worse compared to the benchmark. The present study is therefore an important step towards building a compact system for embedded depth sensing specialized for prosthesis grasping.

Published
2022

4. Statistical Characterization of Closed-Loop Latency at the Mobile Edge

Author

Suman, Suraj, Chiariotti, Federico, Stefanovic, Cedomir, Dosen, Strahinja, and Popovski, Petar

Subjects
Computer Science - Networking and Internet Architecture
Abstract

The stringent timing and reliability requirements in mission-critical applications require a detailed statistical characterization of the latency. Teleoperation is a representative use case, in which a human operator (HO) remotely controls a robot by exchanging command and feedback signals. We present a framework to analyze the latency of a closed-loop teleoperation system consisting of three entities: HO, robot located in remote environment, and a Base Station (BS) with Mobile edge Computing (MEC) capabilities. A model of each component of the system is used to analyze the closed-loop latency and decide upon the optimal compression strategy. The closed-form expression of the distribution of the closed-loop latency is difficult to estimate, such that suitable upper and lower bounds are obtained. We formulate a non-convex optimization problem to minimize the closed-loop latency. Using the obtained upper and lower bound on the closed-loop latency, a computationally efficient procedure to optimize the closed-loop latency is presented. The simulation results reveal that compression of sensing data is not always beneficial, while system design based on average performance leads to under-provisioning and may cause performance degradation. The applicability of the proposed analysis is much wider than teleoperation, for systems whose latency budget consists of many components., Comment: Submitted to IEEE Transactions on Communications

Published
2022

5. Analysis and Optimization of the Latency Budget in Wireless Systems with Mobile Edge Computing

Author

Suman, Suraj, Stefanovic, Cedomir, Došen, Strahinja, and Popovski, Petar

Subjects
Electrical Engineering and Systems Science - Systems and Control, Electrical Engineering and Systems Science - Signal Processing
Abstract

We present a framework to analyse the latency budget in wireless systems with Mobile Edge Computing (MEC). Our focus is on teleoperation and telerobotics, as use cases that are representative of mission-critical uplink-intensive IoT systems with requirements on low latency and high reliability. The study is motivated by a general question: What is the optimal compression strategy in reliability and latency constrained systems? We address this question by studying the latency of an uplink connection from a multi-sensor IoT device to the base station. This is a critical link tasked with a timely and reliable transfer of potentially significant amount of data from the multitude of sensors. We introduce a comprehensive model for the latency budget, incorporating data compression and data transmission. The uplink latency is a random variable whose distribution depends on the computational capabilities of the device and on the properties of the wireless link. We formulate two optimization problems corresponding to two transmission strategies: (1) Outage-constrained, and (2) Latency-constrained. We derive the optimal system parameters under a reliability criterion. We show that the obtained results are superior compared to the ones based on the optimization of the expected latency., Comment: Accepted in IEEE International Conference on Communications (ICC) 2022, Seoul, South Korea

Published
2022

24. Using embedded prosthesis sensors for clinical gait analyses in people with lower limb amputation: A feasibility study

Author

Manz, Sabina, Seifert, Dirk, Altenburg, Bjoern, Schmalz, Thomas, Dosen, Strahinja, and Gonzalez-Vargas, Jose

Subjects
Microprocessor-controlled knee, Embedded sensors, Biophysics, Gait analysis, Prosthesis, Orthopedics and Sports Medicine
Abstract

BACKGROUND: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint.METHODS: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors.FINDINGS: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh).INTERPRETATION: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.

Published
2023
Full Text
View/download PDF

25. Method and neuroprosthetic device for monitoring and suppression of pathological tremors through neurostimulation of the afferent pathways

Author

Rocón, Eduardo, Pons Rovira, José Luis, Farina, Dario, Dosen, Strahinja, Rocón, Eduardo, Pons Rovira, José Luis, Farina, Dario, and Dosen, Strahinja

Abstract

Method and neuroprosthetic device for monitoring and suppression of pathological tremors in a user through the neurostimulation of the afferent pathways to the brain, which comprises wearable elements placed over the parts of the body affected by tremor, wherein said wearable elements (1) have bioelectric sensors (3) generating a first signal characterization of tremor, biomechanical sensors (4) generating a second signal characterization of tremor, a programmable electronic device (9) comprised of a control, acquisition and processing module of the first and second characterization signals, and a signal generator for the afferent stimulation based on the first and second signal characterization and stimulation electrodes (8) which transmit the neuromodulation signals to the afferent pathways projecting into the central nervous system to modulate the activity of the neural structures responsible for tremor generation.

Published
2022

26. Dispositivo neuroprotésico para la monitorización y supresión de temblores patológicos mediante la neuroestimulación de vías aferentes

Author

Rocón, Eduardo, Pons Rovira, José Luis, Farina, Dario, Dosen, Strahinja, Rocón, Eduardo, Pons Rovira, José Luis, Farina, Dario, and Dosen, Strahinja

Abstract

Método y dispositivo neuroprotésico para el monitoreo y la supresión de los temblores patológicos en un usuario a través de la neuroestimulación de las vías aferentes hacia el cerebro, que comprende elementos portátiles colocados sobre las partes del cuerpo afectados por el temblor, en el que dichos elementos portátiles (1) tienen sensores bioeléctricos. (3) Generación de una primera caracterización de señal de temblor, sensores biomecánicos (4) Generación de una segunda caracterización de señal de temblor, un dispositivo electrónico programable (9) compuesto por un módulo de control, adquisición y procesamiento de las señales de caracterización de primera y segunda, y un Generador de señal para la estimulación aferente basada en la primera y segunda caracterización de la señal y electrodos de estimulación (8) que transmiten las señales de neuromodulación a las vías aferentes que se proyectan en el sistema nervioso central para modular la actividad de las estructuras neuronales responsables de la generación de temblores.

Published
2022

34. Statistical Characterization of Closed-Loop Latency at the Mobile Edge

Author

Suman, Suraj, Chiariotti, Federico, Stefanovic, Cedomir, Dosen, Strahinja, and Popovski, Petar

Abstract

The stringent timing and reliability requirements in mission-critical applications require a detailed statistical characterization of end-to-end latency. Teleoperation is a representative use case, in which a human operator (HO) remotely controls a robot by exchanging command and feedback signals. We present a framework to analyze the latency of a closed-loop teleoperation system consisting of three entities: an HO, a robot located in remote environment, and a Base Station (BS) with Mobile edge Computing (MEC) capabilities. A model of each component is used to analyze the closed-loop latency and optimize the compression strategy. The closed-form expression of the distribution of the closed-loop latency is difficult to estimate, such that suitable upper and lower bounds are obtained. We formulate a non-convex optimization problem to minimize the closed-loop latency. Using the obtained upper and lower bound on the closed-loop latency, a computationally efficient procedure to optimize the closed-loop latency is presented. The simulation results reveal that compression of sensing data is not always beneficial, while system design based on average performance leads to under-provisioning and may cause performance degradation. The applicability of the proposed analysis is much wider than teleoperation, including a large class of systems whose latency budget consists of many components.

Published
2023
Full Text
View/download PDF

35. Moving-window dynamic optimization: design of stimulation profiles for walking

Author

Dosen, Strahinja and Popovic, Dejan B.

Subjects
Algorithms -- Usage, Mathematical optimization -- Research, Gait -- Physiological aspects, Walking -- Physiological aspects, Electric stimulation -- Methods, Algorithm, Biological sciences, Business, Computers, Health care industry
Abstract

The overall goal of the research is to improve control for electrical stimulation-based assistance of walking in hemiplegic individuals. We present the simulation for generating offline input (sensors) output (intensity of muscle stimulation) representation of walking that serves in synthesizing a rule-base for control of electrical stimulation for restoration of walking. The simulation uses new algorithm termed moving-window dynamic optimization (MWDO). The optimization criterion was to minimize the sum of the squares of tracking errors from desired trajectories with the penalty function on the total muscle efforts. The MWDO was developed in the MATLAB environment and tested using target trajectories characteristic for slow-to-normal walking recorded in healthy individual and a model with the parameters characterizing the potential hemiplegic user. The outputs of the simulation are piecewise constant intensities of electrical stimulation and trajectories generated when the calculated stimulation is applied to the model. We demonstrated the importance of this simulation by showing the outputs for healthy and hemiplegic individuals, using the same target trajectories. Results of the simulation show that the MWDO is an efficient tool for analyzing achievable trajectories and for determining the stimulation profiles that need to be delivered for good tracking. Index Terms--Biomechanical modeling, functional electrical stimulation (FES), gait restoration, optimal control.

Published
2009

37. Accelerometers and force sensing resistors for optimal control of walking of a hemiplegic

Author

Dosen, Strahinja and Popovic, Dejan B.

Subjects
Resistors -- Usage, Neural networks -- Design and construction, Neural stimulation -- Methods, Gait -- Control, Machine learning -- Research, Hemiplegia -- Care and treatment, Accelerometers -- Usage, Resistor, Neural network, Biological sciences, Business, Computers, Health care industry
Abstract

We developed a method for use of accelerometers and force sensing resistors (FSRs) within an optimal controller of walking for hemiplegic individuals. The data from four dual-axis accelerometers and four FSRs were inputs, while six muscle activation profiles were outputs. The controller includes two stages: 1) estimating the target gait pattern using artificial neural networks; and 2) optimal control minimizing tracking errors (from the estimated gait pattern) and muscle efforts. The controller was tested using data collected from six healthy subjects walking at five speeds (0.6-1.4 m/s). The average root mean square errors (RMSEs) normalized by the peak-to-peak value of the target signals [normalized RMSE (NRMSE)] were below 6%, 7%, 8%, and 3% for estimation of joint angles, hip acceleration, ground reaction force, and movement of the center of pressure, respectively. Using the estimated data as inputs, the simulation generated the target healthy-like gait patterns and reproducible muscle activation profiles in 90% of 300 tested gait trials. Overall tracking NRMSE was between 2% and 9%. The optimal controller was developed for testing the feasibility of healthy-like gait patterns in hemiplegic individuals, and generating a knowledge base that is required for the synthesis of a sensory-driven control of walking assisted by functional electrical stimulation. Index Terms--Artificial neural networks (ANNs), functional electrical stimulation (FES), gait, machine learning, optimal control, sensory system.

Published
2008

38. Soft Active Hand Orthosis

Author

Abdelhafiz, Mohamed, Struijk, Lotte Najanguaq Søvsø Andreasen, Dosen, Strahinja, and Spaich, Erika Geraldina

Subjects
body regions, equipment and supplies, musculoskeletal system
Abstract

The invention relates to a hand orthosis (1) for assisting the movements of a user's hand. The hand orthosis comprises a soft glove (2) adapted to receive at least a part of the user's hand with finger sections of the glove receiving each of the user's fingers. It further comprises at least one actuator box (3), and a power transmission (4) for transferring forces from the at least one actuator box to different parts of the glove via exo-tendons (5). The exo-tendons are arranged on a dorsal side, on a palmar side, or on both a dorsal side and a palmar side of the glove. The exo-tendons are arranged so that the glove can assist flexion, extension, or both extension and flexion of the fingers, respectively and so that the exo-tendons act on the fingers to produce motion that mimics the movement of a human hand. The hand orthosis provides different grasp types, self- adaptation of the fingers' motion to the shape of the object, and physiologically appropriate distribution of finger forces.

Published
2020

39. Introduction to EU-H2020 project WEARPLEX:wearable multiplexed biomedical electrodes - alpha results

Author

Torah, Russel, Komolafe, Abiodun, Beeby, Steve, Kostic, Milos, Strbac, Matija, Keller, Thierry, Perinka, Nikola, Lanceros-Mendez, Senentxu, Ersman, Peter Andersson, Mulla, Yusuf, Polomoshnov, Maxim, Murciego, Luis Pelaez, Dosen, Strahinja, Spaich, Erika G., Wendelbo, Rune, Motealleh, Azadeh, Chardonnens, Severine, Junker, Katja, Isotalo, Jenni, Aalpoel, Roelof, and Tauriainen, Antti

Published
2020

47. Introduction to EU-H2020 project WEARPLEX: wearable multiplexed biomedical electrodes

Author

Torah, Russel, Beeby, Stephen, Kostic, Milos, Keller, Thierry, Lanceros-Mendez, Senentxu, Andersson Ersman, Peter, Zillger, Tino, Dosen, Strahinja, Wendelbo, Rune, Chardonnens, Severine, and Tauriainen, Antti

Abstract

WEARPLEX is a multidisciplinary research and innovation action with the overall aim to integrate printed electronics with flexible and wearable textile-based biomedical multi-pad electrodes. It aims to answer the growing need for user-friendly electrodes for pervasive measurement of electrophysiological signals and application of electrical stimulation. It focuses on the development of the printable electronics and manufacturing processes for stretchable textile based multi-pad electrodes with integrated logic circuits that enable a significant increase in the number of electrode pads (channels) and facilitate the creation of new products in the sectors of medical electronics and life-style. The advanced printed electronics integrated in WEARPLEX electrodes will allow the individual pads to be connected in arbitrary configurations to the output leads of the electrode. Therefore, the pads will be flexibly organized into several virtual electrodes of arbitrary position, shape and size that can be connected to any standard multi-channel recording and stimulation system. In addition, software methods will be developed for automatic calibration of these virtual electrodes, to detect stimulation/recording hotspots and adjust the virtual electrodes accordingly. Therefore, the WEARPLEX project will lead to a new generation of smart electrodes that will be able to adapt simultaneously to the user (wearable and stretchable garment), recording/stimulation scenario (movement type and target muscles) and recording/stimulation system (number of channels). This is a paradigm shift in designing the recording and stimulation systems, as the switching electronics is shifted from the custom-made stimulator/recording device to the smart electrode, leading to a universal solution compatible with any system. WEARPLEX is funded under the EU Horizon2020 call ICT-02-2018, the work program is over 3 years starting on the 1st of January 2019; this abstract is therefore an opportunity to introduce the project to the community and discuss research directions and early results for the project. The individual components of the project are at TRL2-4 with the goal of improving and combining them to achieve TRL6-7 industrial demonstrators by the end of the project.

Published
2019

49. Feel-Good Robotics: Requirements on Touch for Embodiment in Assistive Robotics

Author

Beckerle, Philipp, Kõiva, Risto, Kirchner, Elsa Andrea, Bekrater-Bodmann, Robin, Dosen, Strahinja, Christ, Oliver, Abbink, David A., Castellini, Claudio, Lenggenhager, Bigna, Beckerle, Philipp, Kõiva, Risto, Kirchner, Elsa Andrea, Bekrater-Bodmann, Robin, Dosen, Strahinja, Christ, Oliver, Abbink, David A., Castellini, Claudio, and Lenggenhager, Bigna

Abstract

The feeling of embodiment, i.e., experiencing the body as belonging to oneself and being able to integrate objects into one’s bodily self-representation, is a key aspect of human self-consciousness and has been shown to importantly shape human cognition. An extension of such feelings toward robots has been argued as being crucial for assistive technologies aiming at restoring, extending, or simulating sensorimotor functions. Empirical and theoretical work illustrates the importance of sensory feedback for the feeling of embodiment and also immersion; we focus on the the perceptual level of touch and the role of tactile feedback in various assistive robotic devices. We critically review how different facets of tactile perception in humans, i.e., affective, social, and self-touch, might influence embodiment. This is particularly important as current assistive robotic devices – such as prostheses, orthoses, exoskeletons, and devices for teleoperation–often limit touch low-density and spatially constrained haptic feedback, i.e., the mere touch sensation linked to an action. Here, we analyze, discuss, and propose how and to what degree tactile feedback might increase the embodiment of certain robotic devices, e.g., prostheses, and the feeling of immersion in human-robot interaction, e.g., in teleoperation. Based on recent findings from cognitive psychology on interactive processes between touch and embodiment, we discuss technical solutions for specific applications, which might be used to enhance embodiment, and facilitate the study of how embodiment might alter human-robot interactions. We postulate that high-density and large surface sensing and stimulation are required to foster embodiment of such assistive devices.

Published
2019

50. Improving bimanual interactions between myoelectric prosthesis and sound limb

Author

Volkmar, Robin, Markovic, Marko, and Dosen, Strahinja

Subjects
myocontrol, myoelectric prosthesis, semi-autonomous, wearable system, hand prosthesis, ddc: 610, assistive system, electromyographie, 610 Medical sciences, Medicine, prosthetics, IMU-based, robotic hand
Abstract

Objectives: The loss of a hand is a traumatizing experience that can comprise an individual capability to interact intuitively with his environment. The state-of-the-art (SoA) functional replacement for the lost limbs are myoelectric prostheses. Their overall mechanical design and dexterity have improved[for full text, please go to the a.m. URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

Published
2018

Catalog

Books, media, physical & digital resources
See catalog results