In recent years, technological developments have made it possible to build interactive 3D models of objects and 3D Virtual Environments that can be experienced through the Web, using common, low-cost personal computer...
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Use of laser-driven Inertial Confinement Fusion (ICF) for space propulsion has been examined in several earlier conceptual design studies. However, these designs used older ICF target technology. Important new directi...
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ISBN:
(纸本)9781563479434
Use of laser-driven Inertial Confinement Fusion (ICF) for space propulsion has been examined in several earlier conceptual design studies. However, these designs used older ICF target technology. Important new directions opened following the development of "chirped" lasers capable of ultra-short ps pulses with powers of PWs. This allows fast ignition (FI) for high energy gain ICF power plants1. The FI approach uses a conventional laser to pre-compress the target to high density. The PW laser is then fired on the compressed target, creating an internal electron beam that ignites fusion in a central core of the target. It is estimated that using a 10 TW-ps laser for FI can achieve fusion energy gains >103. Here a new type of FI, termed block ignition, is considered2-4. This approach can further increase the fusion gain offered through FI. Application of block ignition to the earlier VISTA design for ICF space propulsion unit is considered here. With the improved performance obtained, it becomes feasible to bypass DT fusion and use tritium-lean D targets as a first step for development of fusion propulsion technology.
There is increasing interest in the storage, retrieval, and analysis of email communications. One active area of research focuses on the inference of properties of the underlying social network giving rise to the emai...
ISBN:
(纸本)9783540731320
There is increasing interest in the storage, retrieval, and analysis of email communications. One active area of research focuses on the inference of properties of the underlying social network giving rise to the email communications[1,2]. Email communication between individuals implies some type of relationship, whether it is formal, such as a manager-employee relationship, or informal, such as friendship relationships. Understanding the nature of these observed relationships can be problematic given there is a shared context among the individuals that isn’t necessarily communicated. This provides a challenge for analysts that wish to explore and understand email archives for legal or historical research.
We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is availab.e. We show that our log-time algorithm always...
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We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is availab.e. We show that our log-time algorithm always produce faithfully-rounded results, discuss the possibility of getting correctly rounded results, and show that results correctly rounded in double precision can be obtained if extended precision is availab.e with the possibility to round into double precision (with a single rounding).
The Negative Selection Algorithm is an immunology-inspired algorithm for anomaly detection application. This algorithm has been implemented with different pattern representations and various matching rules and success...
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ISBN:
(纸本)1595933158
The Negative Selection Algorithm is an immunology-inspired algorithm for anomaly detection application. This algorithm has been implemented with different pattern representations and various matching rules and successfully applied to a broad range of problems. Recent research shows serious problems with this algorithm in terms of both efficiency and effectiveness. In this paper we evaluated the performance of the algorithm constraint-based representation. We argue that the algorithm and problem representations should be considered separately, and that best performance of the algorithm may be obtained by choosing a proper representation.
Virtual environments (VEs) very often contain buildings that have to be navigated by users. In the literature, several navigation aids based on maps have been proposed for VEs, but in virtual buildings they have been ...
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ISBN:
(纸本)1595933212
Virtual environments (VEs) very often contain buildings that have to be navigated by users. In the literature, several navigation aids based on maps have been proposed for VEs, but in virtual buildings they have been typically used for single-floor scenarios. In this paper, we propose and experimentally evaluate two different navigation aids for multi-floor virtual buildings, one based on 3D maps and the other based on 2D maps. We compared subjects' performance with two different types of tasks: search and direction estimation. While the 2D navigation aid outperformed the 3D one for the search task, there were no significant differences between the two aids for the direction estimation task. Copyright 2006 ACM.
The availab.lity of more powerful mobile devices, sometimes equipped with graphics accelerators, is making it easier to experiment with mobile 3D graphics. In this paper, we exploit the main emerging standard in 3D re...
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Sports and fitness are increasingly attracting the interest of computerscience researchers as well as companies. In particular, recent mobile devices with hardware graphics acceleration offer new, still unexplored po...
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ISBN:
(纸本)1595933905
Sports and fitness are increasingly attracting the interest of computerscience researchers as well as companies. In particular, recent mobile devices with hardware graphics acceleration offer new, still unexplored possibilities. This paper investigates the use of mobile guides in fitness activities, proposing the Mobile Personal Trainer (MOPET) application. MOPET uses a GPS device to monitor user's position during her physical activity in an outdoor fitness trail. It provides navigation assistance by using a fitness trail map and giving speech directions. Moreover, MOPET provides motivation support and exercise demonstrations by using an embodied virtual trainer, called Evita. Evita shows how to correctly perform the exercises along the trail with 3D animations and incites the user. To the best of our knowledge, our project is the first to employ a mobile guide for fitness activities. The effects of MOPET on motivation, as well as its navigational and training support, have been experimentally evaluated with 12 users. Evaluation results encourage the use of mobile guides and embodied virtual trainers in outdoor fitness applications. Copyright 2006 ACM.
作者:
Chittaro, LucaHCI Lab.
Dept. of Math and Computer Science University of Udine via delle Scienze 206 33100 Udine Italy
The capability of accessing, analyzing and possibly updating patients' medical records from anywhere through a mobile device in the hands of clinicians and nurses is considered to be a particularly promising appli...
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ISBN:
(纸本)1595933530
The capability of accessing, analyzing and possibly updating patients' medical records from anywhere through a mobile device in the hands of clinicians and nurses is considered to be a particularly promising application. Information Visualization has explored interactive visual formats to help users in analyzing patient records, but they are meant for the desktop context. This paper begins to explore the problem of visualizing patient record data with the limited display and interaction capabilities of mobile devices, focusing on common PDAs and temporal data. Copyright 2006 ACM.
Browsing large information spaces such as maps on the limited screen of mobile devices often requires people to perform panning and zooming operations that move relevant display content off-screen. This makes it diffi...
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ISBN:
(纸本)1595933905
Browsing large information spaces such as maps on the limited screen of mobile devices often requires people to perform panning and zooming operations that move relevant display content off-screen. This makes it difficult to perform spatial tasks such as finding the location of Points Of Interest (POIs) in a city. Visualizing the location of off-screen objects can mitigate this problem: in this paper, we present a user study comparing the Halo [2] approach with two other techniques based on arrows. Halo surrounds off-screen objects with circles that reach the display window, so that users can derive the location and distance of objects by observing the visible portion of the corresponding circles. In the two arrow-based techniques, arrows point at objects and their size and body length, respectively, inform about the distance of objects. Our study involved four tasks requiring users to identify and compare off-screen objects locations, and also investigated the effectiveness of the three techniques with respect to the number of off-screen objects. Arrows allowed users to order off-screen objects faster and more accurately according to their distance, while Halo allowed users to better identify the correct location of off-screen objects. Implications of these results for mobile map-based applications are also discussed. Copyright 2006 ACM.
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