The dynamics of experimental nuclear reactors exhibit strong non-linearities, while the constraints associated with their operation embody a number of safety-related decision points and protective trips. For power man...
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The dynamics of experimental nuclear reactors exhibit strong non-linearities, while the constraints associated with their operation embody a number of safety-related decision points and protective trips. For power maneuvering, existing control technologies include human operators, state variable feedback controllers, and digital model-based controllers. In this work, we demonstrate the use of an associative stochastic automaton as an alternative. Factors which lead to the success of the application are discussed.
This paper indicates the problems encountered applying concepts of semantic data modeling to the description of complex surface objects from a data modeling perspective. The case study discussed deals with the concept...
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ISBN:
(纸本)0819416967;9780819416964
This paper indicates the problems encountered applying concepts of semantic data modeling to the description of complex surface objects from a data modeling perspective. The case study discussed deals with the concept of terrain mapping units (TMUs). TMUs are complex relief units. The concept of TMU presents a method for conjunctive data acquisition and data capture for use in geographic information systems (GISs). The definition and selection of TMUs are based on an understanding of the terrain pattern in the 3D photo model. Criteria are given for the delineation and selection of TMUs. The criteria yield a descriptive hierarchical classification scheme for TMUs. The study illustrates that problems arise from subsequently data modeling itself, which presents a simplified view of part of the real-world incorporating to a certain extent uncertainty; the classification (labeling) of the delineated terrain objects comprises uncertainties; and ambiguities in the utilized concepts of a specific application field. These problems have to be dealt with in an integrated approach of data acquisition and GIS database design. This paper attempts to illustrate the necessity of an observation theory for the design of GISs.
Toxic contaminants emitted to the atmosphere may be transformed and/or transported to other environmental media such as cater, soil, and biota. Many models have been developed to assess the impact of these emissions o...
Toxic contaminants emitted to the atmosphere may be transformed and/or transported to other environmental media such as cater, soil, and biota. Many models have been developed to assess the impact of these emissions on human health and ecosystems. These models require input of chemical-specific parameters called intermedia transfer factors (ITFs). This study focuses on assessing the accuracy of ITFs used in modeling the enviromental impact of benzene, 2,3,7,8-TCDD and hexavalent chromium because these chemicals pose significant health risks and are widely emitted from various industrial processes. Many of the IFTs cited in the literature were estimated rather than measured which highlights the need for employing the most accurate estimation techniques available. This study can be used to refine the health risk assessment approach for identifying major enviromental hazards caused by industrial emissions and thus elucidating effective control strategies.
The current DoD target acquisition models have two primary deficiencies: they use simplistic representations of the vehicle and background signatures, and a highly simplified description of the human observer. The cur...
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ISBN:
(纸本)0819415286
The current DoD target acquisition models have two primary deficiencies: they use simplistic representations of the vehicle and background signatures, and a highly simplified description of the human observer. The current signature representation often fails for complex signature configurations, yields inaccurate detectability and marginal pay-off predictions for low signature vehicles, is not extensible to false alarms and temporal cues, and precludes vehicle design guidance and diagnosis. The current human observer model is simplified to the same degree as the signature representation, and as such is not extensible to high fidelity signature representations. In answer to the noted deficiencies, we have developed the TARDEC visual model (TVM). We have adopted an alternative approach that is based on emerging academic computational vision models (CVM). Our approach is tailored to visual signatures, though the model is applicable to thermal, SAR as well as other categories of imagery. Color imagery, input to the model, is initially transformed into a 3D color-opponent space comprising luminance, red-green, and yellow- blue axes. Each plane in the color-opponent space is then decomposed by local, oriented spatial frequency analyzers (Gabor or wavelet filters) in keeping with current knowledge of retinal/cortical processing. Signal-to-noise statistics are then calculated on each channel, appropriately aggregated over all channels, and used within the signal detection theory context to predict detection and false alarm probabilities.
The computer technology currently available provides new analytical tools for integrating flight crew equipment for aerospace vehicles more efficiently and rapidly than ever before. The principal new tools are based o...
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This paper indicates the problems encountered applying concepts of semantic data modeling to the description of complex surface objects from a data modeling perspective. The case study discussed deals with the concept...
详细信息
ISBN:
(纸本)0819416967
This paper indicates the problems encountered applying concepts of semantic data modeling to the description of complex surface objects from a data modeling perspective. The case study discussed deals with the concept of terrain mapping units (TMUs). TMUs are complex relief units. The concept of TMU presents a method for conjunctive data acquisition and data capture for use in geographic information systems (GISs). The definition and selection of TMUs are based on an understanding of the terrain pattern in the 3D photo model. Criteria are given for the delineation and selection of TMUs. The criteria yield a descriptive hierarchical classification scheme for TMUs. The study illustrates that problems arise from subsequently data modeling itself, which presents a simplified view of part of the real-world incorporating to a certain extent uncertainty;the classification (labeling) of the delineated terrain objects comprises uncertainties;and ambiguities in the utilized concepts of a specific application field. These problems have to be dealt with in an integrated approach of data acquisition and GIS database design. This paper attempts to illustrate the necessity of an observation theory for the design of GISs.
A reconfigurable, optical, 3D scanning system with sub-second acquisition of human body surface data was designed and simulated. Sensor elements (digital cameras/light beam projectors) that meet resolution, accuracy, ...
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ISBN:
(纸本)0819416908
A reconfigurable, optical, 3D scanning system with sub-second acquisition of human body surface data was designed and simulated. Sensor elements (digital cameras/light beam projectors) that meet resolution, accuracy, and speed requirements are included in the system design. The sensors are interfaced to video frame grabber(s) under computer control resulting in a modular, low cost system. System operation and data processing are performed using a desktop graphics workstation. Surface data collected with this system can be oversampled to improve resolution and accuracy (viewed by overlapping camera/projector pairs). Multi- resolution data can be collected for different surfaces simultaneously or separately. modeling and calibration of this reconfigurable system are achieved via a robust optimal estimation technique. Reconstruction software that allows seamless merging of a range data from multiple sensors has been implemented. Laser scanners that acquire body surface range data using one or two sensors require several seconds for data collection. Surface digitization of inaminate objects is feasible with such devices, but their use in human surface metrology is limited due to motion artifacts and occluded surfaces. Use of multiple, independent active sensors providing rapid collection and multi-resolution data enable sampling of complex human surface morphology not otherwise practical. 3D facial surface data has provided accurate measurements used in facial/craniofacial plastic surgery and modern personal protective equipment systems. Whole body data obtained with this new system is applicable to human factors research, medical diagnosis/treatment, and industrial design.
Toxic contaminants emitted to the atmosphere may be transformed and/or transported to other environmental media such as cater, soil, and biota. Many models have been developed to assess the impact of these emissions o...
详细信息
Toxic contaminants emitted to the atmosphere may be transformed and/or transported to other environmental media such as cater, soil, and biota. Many models have been developed to assess the impact of these emissions on human health and ecosystems. These models require input of chemical-specific parameters called intermedia transfer factors (ITFs). This study focuses on assessing the accuracy of ITFs used in modeling the enviromental impact of benzene, 2,3,7,8-TCDD and hexavalent chromium because these chemicals pose significant health risks and are widely emitted from various industrial processes. Many of the IFTs cited in the literature were estimated rather than measured which highlights the need for employing the most accurate estimation techniques available. This study can be used to refine the health risk assessment approach for identifying major enviromental hazards caused by industrial emissions and thus elucidating effective control strategies.
This paper describes /spl plusmn//spl sigma/ transistor modeling and its application in worst case design of digital integrated circuits. We explore the implicit assumptions made when using the /spl plusmn//spl sigma/...
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This paper describes /spl plusmn//spl sigma/ transistor modeling and its application in worst case design of digital integrated circuits. We explore the implicit assumptions made when using the /spl plusmn//spl sigma/ transistor model, establish the relationship between worst-case design and variability minimization, and extend the variability minimization principles to the worst-case measure reduction. A CMOS delay circuit is used to clarify the discussion.< >
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