Nowadays, touch screens are widely used in many commercial devices. In this paper, we present an inexpensive webcam-based touch screen system based on a simple and generic finger detection technique. Only a single web...
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Nowadays, touch screens are widely used in many commercial devices. In this paper, we present an inexpensive webcam-based touch screen system based on a simple and generic finger detection technique. Only a single webcam and a regular screen are used to achieve this goal. By using the scene geometry and the camera model, we can determine the position of the finger on the screen. The technique we propose is simple and works well under various surrounding environments while the detecting method suits many finger colors and shapes. Our approach can also be used for realtime applications. Experimental results and practical applications are provided to ascertain the proposed method.
Volume visualization is a difficult three-dimensional task and a significant amount of research is devoted to the development of a suitable computerinput device for it. Most of the proposed models use fixed displays,...
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Volume visualization is a difficult three-dimensional task and a significant amount of research is devoted to the development of a suitable computerinput device for it. Most of the proposed models use fixed displays, thus rendering extracted slices in orientations unrelated to their real locations within the volume. We present a new device which takes a different approach, as it leaves the volume in a fixed location and demands the user to change his or her posture to explore it from different angles. To implement this, we built a prototype based on a mobile display equipped with sensors that allows it to track its position, which is related to the location of the slice plane within the volume. Therefore, the user can manipulate this plane by displacing and rotating the display, which is a very intuitive method with minimum learning time. Furthermore, the postural changes required to use the device add a new channel of feedback, which effectively helps to reduce the cognitive load imposed on the user. We built a prototype device and tested it with two groups of volunteers who were asked to use it in a medical imaging application. Statistical analysis of the results shows that explorations made with the proposed device were considerably faster with no penalty in precision. We believe that, with further work, the proposed device can be developed into an useful tool for radiology and neurosurgery. (C) 2011 Elsevier Ltd. All rights reserved.
Performance, reliability and scalability in data-access are key issues in the context of the computing Grid and High Energy Physics data processing and analysis applications, in particular considering the large data s...
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Performance, reliability and scalability in data-access are key issues in the context of the computing Grid and High Energy Physics data processing and analysis applications, in particular considering the large data size and I/O load that a Large Hadron Collider data centre has to support. In this paper we present the technical details and the results of a large scale validation and performance measurement employing different data-access platforms-namely CASTOR, dCache, GPFS and Scalla/Xrootd. The tests have been performed at the CNAF Tier-1, the central computing facility of the Italian National Institute for Nuclear Research (INFN). Our storage back-end was based on Fibre Channel disk-servers organized in a Storage Area Network, being the disk-servers connected to the computing farm via Gigabit LAN. We used 24 disk-servers, 260 TB of raw-disk space and 280 worker nodes as computing clients, able to run concurrently up to about 1100 jobs.' The aim of the test was to perform sequential and random read/write accesses to the data, as well as more realistic access patterns, in order to evaluate efficiency, availability, robustness and performance of the various data-access solutions.
Performance, reliability and scalability in data-access are key issues in the context of the computing Grid and High Energy Physics data processing and analysis applications, in particular considering the large data s...
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Performance, reliability and scalability in data-access are key issues in the context of the computing Grid and High Energy Physics data processing and analysis applications, in particular considering the large data size and I/O load that a Large Hadron Collider data centre has to support. In this paper we present the technical details and the results of a large scale validation and performance measurement employing different data-access platforms-namely CASTOR, dCache, GPFS and Scalla/Xrootd. The tests have been performed at the CNAF Tier-1, the central computing facility of the Italian National Institute for Nuclear Research (INFN). Our storage back-end was based on Fibre Channel disk-servers organized in a Storage Area Network, being the disk-servers connected to the computing farm via Gigabit LAN. We used 24 disk-servers, 260 TB of raw-disk space and 280 worker nodes as computing clients, able to run concurrently up to about 1100 jobs.' The aim of the test was to perform sequential and random read/write accesses to the data, as well as more realistic access patterns, in order to evaluate efficiency, availability, robustness and performance of the various data-access solutions.
Many options exist for prototyping software-based human-computer interfaces, but there are few comparable technologies that allows application developers to create ad-hoc hardware interfaces with corresponding ease an...
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Many options exist for prototyping software-based human-computer interfaces, but there are few comparable technologies that allows application developers to create ad-hoc hardware interfaces with corresponding ease and flexibility. We present a system for rapidly constructing low cost prototypes of mobile input devices by leveraging wireless sensor nodes. We demonstrate two proof-of-concept applications: a conductor's baton and a scene navigation controller, that are prototyped using wireless sensor networks. These applications illustrate that wireless sensor technology can be used to quickly and inexpensively prototype diverse physical user interfaces. We believe that this technology will be of value in many areas, including the study of ergonomics, haptic interfaces, collaborative design, low-cost VR systems, and usability research.
The Finite-Different Time-Domain (FDTD) method has become a popular method in computational electromagnetics because of its simplicity, flexibility, and efficiency. However, the process of generating a three-dimension...
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The Finite-Different Time-Domain (FDTD) method has become a popular method in computational electromagnetics because of its simplicity, flexibility, and efficiency. However, the process of generating a three-dimensional (3D) FDTD grid can be time-consuming and error-prone when manually manipulating complex geometries. In order to expedite the generation of FDTD grids, computer-graphics-based methods can alternatively be used. Starting from the geometric description of the problem domain given by a CAD file, an FDTD grid with a specific spatial resolution can be, automatically produced. A simple algorithm to this end is discussed in this paper, along with sample results.
This work presents a new I/O system design and implementation targeted at applications that perform data streaming. The approach yields true zero-copy transfers between I/O devices in many instances. We give a general...
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This work presents a new I/O system design and implementation targeted at applications that perform data streaming. The approach yields true zero-copy transfers between I/O devices in many instances. We give a general characterization of I/O elements and provide a framework that allows analysis of the potential for zero-copy transfers. Finally, we describe the design, implementation, and performance of a prototype I/O system in a real time, embeddable, 32-bit operating system whose design is based on the presented analysis to minimize data copying.
Although a wealth of educational software exists, severely disabled children cannot benefit from it because of difficulties of access, which is usually via a computer keyboard or mouse. A laser mouse has been develope...
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Although a wealth of educational software exists, severely disabled children cannot benefit from it because of difficulties of access, which is usually via a computer keyboard or mouse. A laser mouse has been developed which enables this software to be utilised. In the case described, the laser source is secured to the front of a head sweat-band but it is small and tight enough to be manipulated by other parts of the body. This method of using a laser beam and photo-cells replaces the standard mouse device to give a severely disabled child the ability to interact with standard commercial software packages. The equipment was developed with the aid of a group of MEng students who responded to a request for help from a local school. Experience of using such a device is given, along with future developments.
A motor go-cart was altered such that a disabled child could control it with a single hand via a joystick. This required: (1) selecting power systems to servo the steering, throttle and brakes; (2) building analogue c...
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A motor go-cart was altered such that a disabled child could control it with a single hand via a joystick. This required: (1) selecting power systems to servo the steering, throttle and brakes; (2) building analogue control circuits and amplifiers to drive and control the power systems; (3) designing and building mechanisms to connect the power systems to the various functions on the go-cart; (4) system testing on a group of disabled and steering problems identification; and (5) modifying a second kart using a 'mechatronic' solution. This entailed taking the driver input to a microprocessor which then controlled the servos. The system could be easily reprogrammed to cope with different demands. This enables the control response of the vehicle to the driver input to be simply varied in accordance with the drivers' skills and abilities and the type of track (i.e. a fast or slow track). For example, the steering sensitivity and the maximum vehicle speed can be programmed for a particular driver.< >
Current virtual reality systems suffer from being almost wholly based on the visual sense. There are many important applications where complementary tactile and kinaesthetic feedback would considerably enhance the ill...
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Current virtual reality systems suffer from being almost wholly based on the visual sense. There are many important applications where complementary tactile and kinaesthetic feedback would considerably enhance the illusion of being immersed in the virtual environment. This paper concentrates on the use of two technologies, shape memory alloy wires and electrorheological fluids to create 2-D programmable surfaces which can be felt by the user in conjunction with the traditional visual display. The technologies are used in different ways. An array of SMA driven tactors is used to create a hard or soft surface which tries to mimic the shape of the required virtual surface. The E-R fluid, following the approach of Monkman (1992), is used as a subcutaneous layer beneath a compliant surface. Areas of this layer can be "rigidised" or "fluidised" under computer control. If the user drags his/her finger across the compliant surface little resistance to motion is felt in the "fluidised" wires but an appreciable resistance is felt in the "rigidised" areas, thereby creating the illusion of the presence of an object.
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