621 research outputs found
Report of the AHG on MPEG-7 Semantic Information Representation
This AHG has been created at the last MPEG meeting in Maui to work in parallel with the CE experiment on the Semantic DS, so as to continue the refinement, both in terms of significance, usage and syntax of the DS’s that have been proposed during the Maui meeting [2] . Following the discussions on the email reflector, the results of a meeting of the US delegation in February and of the discussion during the AHG meeting Mar. 19th, 2000, in Noordwijkerhout, some clarifications were made, though a total convergence has not yet been reached. During the US delagate meeting, an alternative syntax had also been proposed for consideration of the continuation of the CE; it is likely that this will lead to the formulation of competitive solutions to select the best syntax and elementary components of the Semantic DS during the CE process to follow after the 51st MPEG meeting. Below, some listings of the discussions that took place, in reference to the individual mandates of this AHG
Report of CE on Semantic DS
The Semantic DS allows describing the world depicted by the AV content and interpreting that world, i.e., the “about” of the AV content or depicted narrative reality, which sometimes is imaginary. This document reports on the core experiment on the Semantic DS [6]. The CE originally started at the Maui meeting in December 1999 [3]. Progress reports of the CE were provided at the Geneva meeting [1] and at the Beijing meeting [2]. In Beijing, some components of the Semantic DS were promoted to the XM: Semantic DS, Object DS, PersonObject DS, Event DS, State DS, MediaOccurrence DS, SemanticTime DS, SemanticLocation DS, UsageLabel D, and some semantic relations. The main tasks of this core experiment have been the following: 1) To refine the specification of the Semantic DS by solving identified issues; 2) To define the Conceptual DSs; 3) To recommend the standardization of more semantic relations; 4) To investigate the use of membership functions to describe the strength of relations; 5) To generate simple and complex semantic descriptions of multimedia material; 6) To implement a retrieval and browsing application/s that uses the generated descriptions and that shows the functionality of the UsageLabel D, the Conceptual DSs, the State DS, and membership functions for relations, especially; 7) To recommend changes and additions to the Semantic DS based on the results of the experiment. The retrieval application that the CE has accomplished two objectives: (1) to show the utility of the components of the Semantic DS in a retrieval scenario, and (2) to be the software for the MPEG-7 XM platform
Semantics of Multimedia in MPEG-7
In this paper, we present the tools standardized by MPEG-7 for describing the semantics of multimedia. In particular, we focus on the abstraction model, entities, attributes and relations of MPEG-7 semantic descriptions. MPEG-7 tools can describe the semantics of specific instances of multimedia such as one image or one video segment but can also generalize these descriptions either to multiple instances of multimedia or to a set of semantic descriptions. The key components of MPEG-7 semantic descriptions are semantic entities such as objects and events, attributes of these entities such as labels and properties, and, finally, relations of these entities such as an object being the patient of an event. The descriptive power and usability of these tools has been demonstrated in numerous experiments and applications, these make them key candidates to enable intelligent applications that deal with multimedia at human levels
Correlated Prompt Fission Data in Transport Simulations
Detailed information on the fission process can be inferred from the
observation, modeling and theoretical understanding of prompt fission neutron
and -ray~observables. Beyond simple average quantities, the study of
distributions and correlations in prompt data, e.g., multiplicity-dependent
neutron and \gray~spectra, angular distributions of the emitted particles,
-, -, and -~correlations, can place stringent
constraints on fission models and parameters that would otherwise be free to be
tuned separately to represent individual fission observables. The FREYA~and
CGMF~codes have been developed to follow the sequential emissions of prompt
neutrons and -rays~from the initial excited fission fragments produced
right after scission. Both codes implement Monte Carlo techniques to sample
initial fission fragment configurations in mass, charge and kinetic energy and
sample probabilities of neutron and ~emission at each stage of the
decay. This approach naturally leads to using simple but powerful statistical
techniques to infer distributions and correlations among many observables and
model parameters. The comparison of model calculations with experimental data
provides a rich arena for testing various nuclear physics models such as those
related to the nuclear structure and level densities of neutron-rich nuclei,
the -ray~strength functions of dipole and quadrupole transitions, the
mechanism for dividing the excitation energy between the two nascent fragments
near scission, and the mechanisms behind the production of angular momentum in
the fragments, etc. Beyond the obvious interest from a fundamental physics
point of view, such studies are also important for addressing data needs in
various nuclear applications. (See text for full abstract.)Comment: 39 pages, 57 figure files, published in Eur. Phys. J. A, reference
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Report of CE on Semantic DS
ISO/IEC JTC1/SC29/WG11, MPEG00/M6355, 53rd meeting, Jul. 2000, Beijing, PR
Handling qualities of a wide-body transport airplane utilizing Pitch Active Control Systems (PACS) for relaxed static stability application
Piloted simulation studies have been conducted to evaluate the effectiveness of two pitch active control systems (PACS) on the flying qualities of a wide-body transport airplane when operating at negative static margins. These two pitch active control systems consisted of a simple 'near-term' PACS and a more complex 'advanced' PACS. Eight different flight conditions, representing the entire flight envelope, were evaluated with emphasis on the cruise flight conditions. These studies were made utilizing the Langley Visual/Motion Simulator (VMS) which has six degrees of freedom. The simulation tests indicated that (1) the flying qualities of the baseline aircraft (PACS off) for the cruise and other high-speed flight conditions were unacceptable at center-of-gravity positions aft of the neutral static stability point; (2) within the linear static stability flight envelope, the near-term PACS provided acceptable flying qualities for static stabilty margins to -3 percent; and (3) with the advanced PACS operative, the flying qualities were demonstrated to be good (satisfactory to very acceptable) for static stabilty margins to -20 percent
Report of CE on Semantic DS
This document reports on the core experiment on the Semantic DS [5]. The Semantic DS allows describing the world depicted by the AV content and interpreting that world, i.e., the “about” of the AV content or depicted narrative reality, which sometimes is imaginary. The CE originally started at the Maui meeting in December 1999 [4]. Progress reports of the CE were provided at the Geneva meeting [1], at the Beijing meeting [3], and at the La Baule meeting [2]. In La Baule, some components of the Semantic DS were promoted to the WD - Semantic DS, SemanticBase DS, Object DS, Event DS, AgentObject DS, SemanticPlace DS, SemanticTime DS, MediaOccurrence DS, and semantic relations-, and others were promoted to the XM – SemanticState DS, Concept DS, and AbstractionLevel datatype. The goal of this CE is to continue the refinement and evaluation of the Semantic DS and to continue the evaluation of the use of membership functions to describe relation strength. The AbstractionLevel datatype was promoted to CD before Pisa. At Pisa, the work to update the specification of the the SemanticTime, SemanticPlace, and Event DSs and to explain the methods for abstraction and the use of abstract concepts was started. The main tasks of this core experiment have been the following: 1. To refine the specification of the Semantic DS by solving open issues identified by reviewers and previous CEs; 2. To recommend the standardization of more semantic relations; 3. To continue the investigation of the use of membership functions to describe the strength of relations; 4. To generate simple and complex semantic descriptions of multimedia material, 5. To continue the implementation of a retrieval and browsing application/s that use/s the generated descriptions and that show/s the functionality of the DSs in the MDS XM, and 6. To recommend changes and additions to the Semantic DS based on the results of the experiment. The retrieval application that the CE continued the development of the software that had already been integrated into the XM for the Semantic DS
Work-Unit Absenteeism: Effects of Satisfaction, Commitment, Labor Market Conditions, and Time
Prior research is limited in explaining absenteeism at the unit level and over time. We developed and tested a model of unit-level absenteeism using five waves of data collected over six years from 115 work units in a large state agency. Unit-level job satisfaction, organizational commitment, and local unemployment were modeled as time-varying predictors of absenteeism. Shared satisfaction and commitment interacted in predicting absenteeism but were not related to the rate of change in absenteeism over time. Unit-level satisfaction and commitment were more strongly related to absenteeism when units were located in areas with plentiful job alternatives
L-1011 testing with relaxed static stability
Wind tunnel and flight tests indicate that fuel savings of 2 percent can be achieved by center of gravity (C.G.) management for an L-1011 with the current wing configuration. The normal c.b. location is at 25 percent mean aerodynamic center (MAC). The maximum fuel saving occurs for a C.G. location of 35 percent MAC. However, flight at 35 percent requires that the C.G. range be extended aft of the 35-percent point. Flight at C.G. locations aft or 35 percent requires a pitch active control system (PACS) so that handling qualities are not significantly degraded. The development of this PACS is discussed
Longer wings for faster springs – wing length relates tospring phenology in a long-distanc e migrant across its range
In migratory birds, morphological adaptations for efficient migratory flight often oppose morphological adaptations for efficient behavior during resident periods. This includes adaptations in wing shape for either flying long distances or foraging in the vegetation and in climate-driven variation of body size. In addition, the timing of migratory flights and particularly the timely arrival at local breeding sites is crucial because fitness prospects depend on site-specific phenology. Thus, adaptations for efficient long-distance flights might be also related to conditions at destination areas. For an obligatory long-distance migrant, the common nightingale, we verified that wing length as the aerodynamically important trait, but not structural body size increased from the western to the eastern parts of the species range. In contrast with expectation from aerodynamic theory, however, wing length did not increase with increasing migration distances. Instead, wing length was associated with the phenology at breeding destinations, namely the speed of local spring green-up. We argue that longer wings are beneficial for adjusting migration speed to local conditions for birds breeding in habitats with fast spring green-up and thus short optimal arrival periods. We suggest that the speed of spring green-up at breeding sites is a fundamental variable determining the timing of migration that fine tune phenotypes in migrants across their range
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