Ejection seat cushions in current U.S. Air Force aircraft are not suitable for comfort during extended missions. Specific physiological problems such as buttock, leg and back pain, numbness and tingling in the extremi...
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Ejection seat cushions in current U.S. Air Force aircraft are not suitable for comfort during extended missions. Specific physiological problems such as buttock, leg and back pain, numbness and tingling in the extremities, and overall fatigue have been documented in past laboratory research and operational use [1,2,3,5,6]. designing a single cushion to address the physiological problems of the entire aircrew population is a significant challenge. Cushion material selection, cockpit space restrictions, and limited ability to reposition during flight contribute to discomfort during extended missions. Ejection seat dimensions and contours are fixed in most cases, causing accommodation problems for large and small occupants. A pilot study was performed at the Air Force Research Laboratory at Wright-Patterson Air Force Base to investigate objective test methods for determining cushion comfort. Five volunteer subjects were tested with a variety of operational and prototype cushions. Peak seated pressures, contact areas, and lumbar spinal shapes were measured for each cushion. Tests ranged from six-minute quick looks to gather comparative objective measurements, to four-hour extended seating tests to gather subjective and performance data. The study showed objective test methods could be used to identify comfort trends for different cushion candidates. Seated peak pressures and contact areas differed among the cushion specimens that were tested. Trends in subject performance and comfort ratings were also shown. Alternate pressure and shape measurement test equipment and data analysis techniques should be investigated. The data also show that the comfort characteristics of current operational equipment could be improved.
The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) is one of the most promising techniques to achieve broadband wireless communications. Channel estimation is critical in the d...
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The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) is one of the most promising techniques to achieve broadband wireless communications. Channel estimation is critical in the design of MIMO OFDM systems, since channel parameters are required for coherent detection and decoding. In this work, we propose a channel estimation scheme based on the time of arrivals (TOAs) estimation. The TOAs are first determined using a variant of probabilistic data association (PDA) and employing the minimum description length principle, then the PDA is augmented by group decision feedback to refine the TOA estimates. The proposed algorithm is compared with the Fourier transform based method and the alternating projection (AP) algorithm. Simulation results show that the proposed scheme provides the performance comparable to that of AP and much better than that of the Fourier based method, meanwhile it requires much lower computational cost than that of AP.
The design of artifacts and environments for people with disabilities has been frustrated by the lack of design oriented digitalhuman Models (DHM). This paper describes a process for the development of a Functional V...
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ISBN:
(纸本)0769516564
The design of artifacts and environments for people with disabilities has been frustrated by the lack of design oriented digitalhuman Models (DHM). This paper describes a process for the development of a Functional Visualization System (FVS) for the creation of DHM for use by designers and progress made in the development of the FVS. The System employs a 'synthetic' or 'human figure model' approach and includes standard measurement procedures for the capture of anthropometric data, the development of computer programs and processes for the visualization of the data which has been captured, the verification of collected data and the investigation of the utilization of visualization tools by designers and clinicians.
Hamilton Sundstrand Grand Junction has been developing master model techniques and their application in manufacturing processes. Using UG CAD/CAM software solid modeling, assembly, and wave-linking tools in a master m...
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A complete 3D virtual model of the major structures of the ear responsible for the transfer of sound was constructed using computer-aided design (CAD) software. The model was created from the digital images of histolo...
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ISBN:
(纸本)0780376129
A complete 3D virtual model of the major structures of the ear responsible for the transfer of sound was constructed using computer-aided design (CAD) software. The model was created from the digital images of histological sections of a human temporal bone. These images were enhanced, resized, and aligned with respect to four fiducial marks using photo management software. Each structure of the ear including the external ear canal, middle ear, and cochlea was extracted from the sections and arranged to produce a complete 3D model within the SolidWorks environment. The individual structures can then be combined to produce a complete model of the entire human ear. The model will be used for analysis and further advanced modeling techniques.
"Functional Virtual Prototyping" is a process for designing the function of a complex system, such as aircraft landing gear or flight controls, in a computer-based environment. The process can be used to exp...
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This article explains a modeling methodology of human physiology. An agent-based approach to a physiological digitalhuman is proposed, and its design concept and architectural framework are discussed. The modeling is...
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This article explains a modeling methodology of human physiology. An agent-based approach to a physiological digitalhuman is proposed, and its design concept and architectural framework are discussed. The modeling is based on two types of agents: stationary agents which model human physiology, and mobile agents that model parameter interaction between the user and the human physiological model. The human thermoregulatory system is chosen as an example of model functions. A Java-based agent system is shown as an implementation of the model.
The design of artifacts and environments for people with disabilities has been frustrated by the lack of design oriented digitalhuman models (DHM). This paper describes a process for the development of a functional v...
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The design of artifacts and environments for people with disabilities has been frustrated by the lack of design oriented digitalhuman models (DHM). This paper describes a process for the development of a functional visualization system (FVS) for the creation of DHM for use by designers and progress made in the development of the FVS. The system employs a 'synthetic' or 'human figure model' approach and includes standard measurement procedures for the capture of anthropometric data, the development of computer programs and processes for the visualization of the data which has been captured, the verification of collected data and the investigation of the utilization of visualization tools by designers and clinicians.
A complete 3D virtual model of the major structures of the ear responsible for the transfer of sound was constructed using computer-aided design (CAD) software. The model was created from the digital images of histolo...
详细信息
A complete 3D virtual model of the major structures of the ear responsible for the transfer of sound was constructed using computer-aided design (CAD) software. The model was created from the digital images of histological sections of a human temporal bone. These images were enhanced, resized, and aligned with respect to four fiducial marks using photo management software. Each structure of the ear including the external ear canal, middle ear, and cochlea was extracted from the sections and arranged to produce a complete 3D model within the SolidWorks environment. The individual structures can then be combined to produce a complete model of the entire human ear. The model will be used for analysis and further advanced modeling techniques.
We present a survey of our recent research on the development of haptic interfaces for simulating creative processes with digital media, including 3D multiresolution modeling and 2D and 3D painting. We discuss the des...
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We present a survey of our recent research on the development of haptic interfaces for simulating creative processes with digital media, including 3D multiresolution modeling and 2D and 3D painting. We discuss the design issues involved and lessons learned. Based on the preliminary user studies, we observe that haptic interfaces can improve the level of usability of digitaldesign systems and assist in capturing the feel of creative processes.
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