368,640 research outputs found

    The design and implementation of a smartphone and Bluetooth-based criminal tracking system

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    This thesis describes the design and implementation of a real-time criminal tracking system. A criminal under tracking is asked to wear a low energy Bluetooth device and carry a smartphone. The Bluetooth device is secure on his body (e.g., hand or foot) and communicates with the smartphone, which communicates with a central server through cellular networks. The smartphone monitors the status of the Bluetooth device and reports to the server in real time when the status changes (e.g., connection lost or device being taken off). Moreover, it monitors the criminal\u27s movement and reports to the server whenever the criminal moves into an alert zone, a geographic region where the law enforcement wants the criminal\u27s movement to be tracked. Compared to the existing tracking approaches, our system has the following desired features. 1) Scalable. Instead of having a criminal to report its location all the time, the system allows one to configure where and when the criminal needs to be tracked, thus minimizing both mobile communication cost and server processing cost. 2) Low-cost. The system uses only off-shelf components (e.g., Bluetooth device and smartphone) which communicate through regular wireless networks. 3) Secure. The communication between a Bluetooth device and the corresponding smartphone is authenticated through One Time Password

    F2move: fMRI-compatible haptic object manipulation system for closed-loop motor control studies

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    Functional neuroimaging plays a key role in addressing open questions in systems and motor neuroscience directly applicable to brain machine interfaces. Building on our low-cost motion capture technology (fMOVE), we developed f2MOVE, an fMRI-compatible system for 6DOF goal-directed hand and wrist movements of human subjects enabling closed-loop sensorimotor haptic experiments with simultaneous neuroimaging. f2MOVE uses a high-zoom lens high frame rate camera and a motion tracking algorithm that tracks in real-time the position of special markers attached to a hand-held object in a novel customized haptic interface. The system operates with high update rate (120 Hz) and sufficiently low time delays (<; 20 ms) to enable visual feedback while complex, goal-oriented movements are recorded. We present here both the accuracy of our motion tracking against a reference signal and the efficacy of the system to evoke motor control specific brain activations in healthy subjects. Our technology and approach thus support the real-time, closed-loop study of the neural foundations of complex haptic motor tasks using neuroimaging

    Elbow Flexion and Extension Rehabilitation Exercise System Using Marker-less Kinect-based Method

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    This paper presents the elbow flexion and extension rehabilitation exercise system using marker-less Kinect-based method. The proposed exercise system is developed for the upper limb rehabilitation application that utilizes a low cost depth sensor. In this study, the Kinect skeleton tracking method is used to detect and track the joints of upper limb and then measure the angle of the elbow joint. The users perform the exercise in front of the Kinect sensor and the computer monitor. At the same time, they can see the results that displayed on the screen in real-time. The measurement of elbow joint angles are recorded automatically and has been compared to the reference values for the analysis and validation. These reference values are obtained from the normal range of motion (ROM) of the elbow. The results show the average flexion angle of the elbow joint that achieved by the normal user is 139.1° for the right hand and 139.2° for the left hand. Meanwhile, the average extension angle is 1.72° for the right hand and 2.0° for the left. These measurements are almost similar to the standard range of motion (ROM) reference values. The skeleton tracking works well and able to follow the movement of the upper arm and forearm in real-time

    Intelligent composite layup by the application of low cost tracking and projection technologies

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    Hand layup is still the dominant forming process for the creation of the widest range of complex geometry and mixed material composite parts. However, this process is still poorly understood and informed, limiting productivity. This paper seeks to address this issue by proposing a novel and low cost system enabling a laminator to be guided in real-time, based on a predetermined instruction set, thus improving the standardisation of produced components. Within this paper the current methodologies are critiqued and future trends are predicted, prior to introducing the required input and outputs, and developing the implemented system. As a demonstrator a U-Shaped component typical of the complex geometry found in many difficult to manufacture composite parts was chosen, and its drapeability assessed by the use of a kinematic drape simulation tool. An experienced laminator's knowledgebase was then used to divide the tool into a finite number of features, with layup conducted by projecting and sequentially highlighting target features while tracking a laminator's hand movements across the ply. The system has been implemented with affordable hardware and demonstrates tangible benefits in comparison to currently employed laser-based systems. It has shown remarkable success to date, with rapid Technology Readiness Level advancement. This is a major stepping stone towards augmenting manual labour, with further benefits including more appropriate automation

    Real-time 3D tracking of laparoscopy training instruments for assessment and feedback

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    Assessment of minimally invasive surgical skills is a non-trivial task, usually requiring the presence and time of expert observers, including subjectivity and requiring special and expensive equipment and software. Although there are virtual simulators that provide self-assessment features, they are limited as the trainee loses the immediate feedback from realistic physical interaction. The physical training boxes, on the other hand, preserve the immediate physical feedback, but lack the automated self-assessment facilities. This study develops an algorithm for real-time tracking of laparoscopy instruments in the video cues of a standard physical laparoscopy training box with a single fisheye camera. The developed visual tracking algorithm recovers the 3D positions of the laparoscopic instrument tips, to which simple colored tapes (markers) are attached. With such system, the extracted instrument trajectories can be digitally processed, and automated self-assessment feedback can be provided. In this way, both the physical interaction feedback would be preserved and the need for the observance of an expert would be overcome. Real-time instrument tracking with a suitable assessment criterion would constitute a significant step towards provision of real-time (immediate) feedback to correct trainee actions and show them how the action should be performed. This study is a step towards achieving this with a low cost, automated, and widely applicable laparoscopy training and assessment system using a standard physical training box equipped with a fisheye camera

    MOCA: A Low-Power, Low-Cost Motion Capture System Based on Integrated Accelerometers

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    Human-computer interaction (HCI) and virtual reality applications pose the challenge of enabling real-time interfaces for natural interaction. Gesture recognition based on body-mounted accelerometers has been proposed as a viable solution to translate patterns of movements that are associated with user commands, thus substituting point-and-click methods or other cumbersome input devices. On the other hand, cost and power constraints make the implementation of a natural and efficient interface suitable for consumer applications a critical task. Even though several gesture recognition solutions exist, their use in HCI context has been poorly characterized. For this reason, in this paper, we consider a low-cost/low-power wearable motion tracking system based on integrated accelerometers called motion capture with accelerometers (MOCA) that we evaluated for navigation in virtual spaces. Recognition is based on a geometric algorithm that enables efficient and robust detection of rotational movements. Our objective is to demonstrate that such a low-cost and a low-power implementation is suitable for HCI applications. To this purpose, we characterized the system from both a quantitative point of view and a qualitative point of view. First, we performed static and dynamic assessment of movement recognition accuracy. Second, we evaluated the effectiveness of user experience using a 3D game application as a test bed

    Controller design for haptic systems under delayed position and velocity feedback

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    Ankara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Sciences of Bilkent University, 2012.Thesis (Master's) -- Bilkent University, 2012.Includes bibliographical refences.This thesis considers controller design for haptic systems under delayed position and velocity feedback. More precisely, a complete stability analysis of a haptic system, where local dynamics are described by some second-order mechanical dynamics, is presented. Characteristic equation of this system with time delays involves quasipolynomials. By a change of variables in the characteristic equation, stability conditions are obtained analytically and regions are plotted by using Matlab. Next, using two optimization techniques (H∞ and stability margin optimization) optimal choice for the controller gains is proposed. H∞ optimization minimizes tracking error between devices while avoiding large control action inputs. H∞ analysis requires high computational cost for accurate results due to its dependency to frequency domain. On the other hand, stability margin optimization defines a cost function that expresses the trade-off between system bandwidth and robustness with low computational cost. The derived results are tested on a three degree of freedom real-time experimental platform to illustrate the theoretical results. Finally robustness analysis is performed for optimal parameters to find allowable delay perturbationsKoru, Ahmet TahaM.S

    Motion tracking to support surgical skill feedback and evaluation

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    Introduction & Aims Performance evaluation of technical surgical skill is done by direct observation by expert surgeons. This is time intensive, costly, and requires training of assessors. Motion tracking could complement direct observation to provide immediate feedback during training and to support objective performance assessment. A recent study by Ahmed et al. (2017) showed that expert feedback combined with validated metrics resulted in greater performance improvement for novices. However, current motion tracking methods are expensive, non-portable, or very sensitive to disturbances from the environment. We hypothesize that combining technologies solves these limitations. The goal of the current study was to design a wireless, low-cost motion tracking system to support 1) real-time individual performance feedback and 2) objective assessment of technical surgical skills. Description An iterative, research-based design process with rapid prototyping was followed. First, we performed a needs assessment with a literature review and survey to a broad range of surgeons to identify relevant motion parameters. Second, various prototypes using an Inertial Measurement Unit (IMU) and a Leap motion sensor were tested in an authentic surgical environment for 1) robustness and 2) accuracy. Outcomes Twelve surgeons (experience range = 2 - 27 years) from five different hospitals and a range of surgical specialties completed the survey and rated ‘precision of movement’ and ‘minimizing unnecessary movements’ as most important motion parameters of surgical skill. Furthermore, unnecessary or excessive movements and secondary tissue damage were reported as most common errors. The final prototype can be seen in Figure 1. The IMU is embedded in a sleeve and detects fine motor skills such as small hand movements, tremors, and strokes. The Leap Motion sensors complement this with infrared tracking of the hand in 3D space and time. The devices proved robust under changing lighting and gowning conditions. Accuracy of motion tracking was however influenced by instrument use. Discussion Our device offers the possibility for immediate performance feedback aiding trainees’ self-assessment during training. By discriminating good from poor performers in training early on, training can be adapted to an individual trainee’s needs and facilitate deliberate practice. Future research includes expert benchmarking and parameter selection. Motion tracking analysis complements subjective assessment that is prone to bias and reduces assessors’ workload. Novelty of methodology Motion tracking to support surgical skill assessment is not yet common practice. The device offers a robust, affordable, and wearable alternative to current motion tracking devices

    A Real-Time Communication Framework for Wireless Sensor Networks

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    Recent advances in miniaturization and low power design have led to a flurry of activity in wireless sensor networks. Sensor networks have different constraints than traditional wired networks. A wireless sensor network is a special network with large numbers of nodes equipped with embedded processors, sensors, and radios. These nodes collaborate to accomplish a common task such as environment monitoring or asset tracking. In many applications, sensor nodes will be deployed in an ad-hoc fashion without careful planning. They must organize themselves to form a multihop, wireless communication network. In sensor network environments, much research has been conducted in areas such as power consumption, self-organisation techniques, routing between the sensors, and the communication between the sensor and the sink. On the other hand, real-time communication with the Quality of Service (QoS) concept in wireless sensor networks is still an open research field. Most protocols either ignore real time or simply attempt to process as fast as possible and hope that this speed is sufficient to meet the deadline. However, the introduction of real-time communication has created additional challenges in this area. The sensor node spends most of its life routing packets from one node to another until the packet reaches the sink; therefore, the node functions as a small router most of the time. Since sensor networks deal with time-critical applications, it is often necessary for communication to meet real time constraints. However, research that deals with providing QoS guarantees for real-time traffic in sensor networks is still in its infancy.This thesis presents a real-time communication framework to provide quality of service in sensor networks environments. The proposed framework consists of four components: First, present an analytical model for implementing Priority Queuing (PQ) in a sensor node to calculate the queuing delay. The exact packet delay for corresponding classes is calculated. Further, the analytical results are validated through an extensive simulation study. Second, report on a novel analytical model based on a limited service polling discipline. The model is based on an M/D/1 queuing system (a special class of M/G/1 queuing systems), which takes into account two different classes of traffic in a sensor node. The proposed model implements two queues in a sensor node that are served in a round robin fashion. The exact queuing delay in a sensor node for corresponding classes is calculated. Then, the analytical results are validated through an extensive simulation study. Third, exhibit a novel packet delivery mechanism, namely the Multiple Level Stateless Protocol (MLSP), as a real-time protocol for sensor networks to guarantee the traffic in wireless sensor networks. MLSP improves the packet loss rate and the handling of holes in sensor network much better than its counterpart, MMSPEED. It also introduces the k-limited polling model for the first time. In addition, the whole sending packets dropped significantly compared to MMSPEED, which it leads to decrease the consumption power. Fourth, explain a new framework for moving data from the sink to the user, at a low cost and low power, using the Universal Mobile Telecommunication System (UMTS), which is standard for the Third Generation Mobile System (3G). The integration of sensor networks with the 3G mobile network infrastructure will reduce the cost of building new infrastructures and enable the large-scale deployment of sensor network
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