Accurate simulation of interconnect effects is an increasingly critical step in high speed deep submicron design. With ever increasing frequency of digital/analog signals, the traditional lumped RC elements may not be...
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ISBN:
(纸本)0769501044
Accurate simulation of interconnect effects is an increasingly critical step in high speed deep submicron design. With ever increasing frequency of digital/analog signals, the traditional lumped RC elements may not be accurate enough in modeling RC interconnects in VLSI applications due to the distributed nature of realistic interconnects. In this paper a novel analytic time-domain model for distributed RC interconnects is developed for application in nonlinear circuit simulators. The exact analytical solution is derived under the assumption of piecewise-linear signal waveforms at the two ports of the line. We have incorporated this model into a general purpose circuit simulator using the SWEC technique.
Continuous scaling of submicron CMOS technologies will soon make low cost, wireless system-on-a-chip communication products possible. The ultimate goal of these systems is to integrate the entire RF front-end with DSP...
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Continuous scaling of submicron CMOS technologies will soon make low cost, wireless system-on-a-chip communication products possible. The ultimate goal of these systems is to integrate the entire RF front-end with DSP together on a single chip. One key issue to the success of this CMOS RF system LSI chip implementation is how to accurately predict circuit performance using simulators such as SPICE. This will require accurate RF AC and noise models. The latter is essential for optimizing the noise performance which will in turn lead to a low power design. Recently, several CMOS RF models have been proposed for improvement on the accuracy of AC analysis at high frequencies (Ou et al, 1998). However, the accuracy of the existing noise models is not satisfactory for submicron CMOS. In this paper, a physics-based RF thermal noise model is proposed for submicron CMOS devices with a channel thermal noise model, resulting in a nearly bias-independent noise factor /spl gamma/. This model shows good agreement with measured RF noise data across a wide range of bias conditions.
Prostate malignancies are the second leading cause of cancer deaths among men. The most common method of detecting this disease is digital rectal examination (DRE). Current DRE training is inadequate, since the number...
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Prostate malignancies are the second leading cause of cancer deaths among men. The most common method of detecting this disease is digital rectal examination (DRE). Current DRE training is inadequate, since the number of patients that students can practice on is limited. Furthermore, allied care personnel do not train in screening for prostate cancer. Finally, there is no objective may to follow the improvement in DRE skills for medical personnel. This paper presents a virtual reality-based simulator that addresses the above problems. The prototype consists of a PHANToM haptic interface which provides feedback to the trainee's index finger, a motion restricting board, and an SGI workstation, which renders the patient's anatomy. Four types of prostates mere modeled-normal, enlarged with no tumor, incipient malignancy (single tumor), and advanced malignancy (tumor cluster). human factors studies mere conducted on both nonmedical students and urology residents in order to quantify the system usefulness. After only five minutes of training, nonmedical students had a 67% correct diagnosis rate of malignant versus nonmalignant cases. This compared with 56% for urology residents in the same trials. Subjective evaluation by the residents pointed out the heed to improve the virtual prostate model realism. A control group formed of urology residents performed the same trials on a modified Merck Procar simulator. The control group scored significantly better (96% correct diagnosis of malignancies). We conclude that the virtual prostate palpation simulator, while promising, needs significant improvement in both model realism and haptic interface hardware.
This paper surveys recent advances in communications that utilize soft computing approaches to phase synchronization. Soft computing, as opposed to hard computing, is a collection of complementary methodologies that a...
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This paper surveys recent advances in communications that utilize soft computing approaches to phase synchronization. Soft computing, as opposed to hard computing, is a collection of complementary methodologies that act in producing the most desirable control, decision, or estimation strategies. Recently, the communications area has explored the use of the principal constituents of soft computing, namely, fuzzy logic, neural networks, and genetic algorithms, for modeling, control, and most recently for the estimation of phase in phase-coherent communications. If the receiver in a digital communications system is phase-coherent as is often the case, phase synchronization is required. Synchronization thus requires estimation and/or control at the receiver of an unknown or random phase offset.
The estimates for the rate constants in compartment model analysis of /sup 18/F-FDG PET are affected by the fraction of tissue mixture in the ROI, which depends both on the spatial resolution and on the size of the RO...
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The estimates for the rate constants in compartment model analysis of /sup 18/F-FDG PET are affected by the fraction of tissue mixture in the ROI, which depends both on the spatial resolution and on the size of the ROI. At first we have evaluated the relationship between the Recovery Coefficient (RC) and estimates of /sup 18/F-FDG rate constants in a ROI without tissue mixture by using a segmented striatum phantom with various resolution. The RC was calculated as the percentage of ROI value to the true activity in the ROI. Next, we have investigated the relationship among the estimates of /sup 18/F-FDG rate constants, spatial resolution and ROI size for the striatum and cerebral cortex, using dynamic digital brain phantom. The activity time course in each tissue was determined with a three-parameter model for /sup 18/F-FDG. Noise was generated by Poisson process according to the collected count for each frame. Sinograms with various spatial resolutions were produced by forward projection, and the images were reconstructed by filtered backprojection method with spatial resolution of 2-12 [mm FWHM]. The parameters (K1, k2, k3, CMRGlc) were estimated by Modified Marquardt method. The fractional tissue component (FTC) was determined as the percentage of the target tissue volume in the total volume of the ROI in the smoothed images. The values of estimates linearly correlated with the FTC for the ROIs with various sizes. The true value was estimated as an extrapolation to 100 [%] FTC on the linear regression line. When this method was applied to the human data for three normal subjects, the estimates also linearly correlated with the FTC and the value at 100 [%] FTC was obtained as a partial volume corrected parameter estimate.
With advancing technology, the use of computer models of the human body for evaluating cockpit designs and modifications is growing more popular. digitalhumanmodeling systems are proving to be invaluable in cockpit ...
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With advancing technology, the use of computer models of the human body for evaluating cockpit designs and modifications is growing more popular. digitalhumanmodeling systems are proving to be invaluable in cockpit design. In our experience, however, modeling systems lack a needed level of realism, or biofidelity, which is essential if they are also to be used as effective evaluation tools in cockpit accommodation studies. For this reason we have started to develop a validation technique for humanmodeling systems in the cockpit environment. Once the technique is established it will permit 1) comparative performance results to be gathered on humanmodeling systems in the cockpit environment, and 2) provide data to increase realism in each modeling system. The base-line data and the validation method will be offered to anyone conducting work in humanmodeling. This work will also serve as a basis for a transition to conducting cockpit accommodation studies almost entirely in the digital realm. This paper provides an overview of our validation technique, and we hope it stimulates criticism and advice from the humanmodeling community and from crew station designers. We welcome your comments and suggestions.
The proceedings contain 26 papers. The topics discussed include: an eclectilc approach to complexity from a human-centered perspective;the ecological expert: acting to create information to guide action;whom (or what)...
ISBN:
(纸本)0818683414
The proceedings contain 26 papers. The topics discussed include: an eclectilc approach to complexity from a human-centered perspective;the ecological expert: acting to create information to guide action;whom (or what) do you (mis)trust?: historical reflections on the psychology and sociology of information technology;human error revisited: some lessons for situation awareness;implications of a control-theoretic approach to human-automation-plant interface design;human-machine performance configuration for multidimensional and multi-modal interaction in virtual environments;describing the design contributors to mode error;hands-free input devices for wearable computers;hysteresis in hand-eye coordination;surgical strike: interface design across task domains;metacognitive systems engineering: thinking critically about CSE;toward every-citizen interfaces to the nation's information infrastructure: a national research council study;investigating the effects of problem format and task related experience on evidential reasoning;decision support display modeling for digital battlefield;cognitive activities and support in debugging;pilot performance with mid-flight plan-based display changes;need for multi-aspect measures to support evaluation of complex human-computer interfaces;human interactions with heterogeneous information sources;and human-computer anxiety and phobia: a consideration of foundations and interventions.
Deneb's Interactive Graphic Robot Instruction Progam (IGRIP) and Envision software packages with the Ergonomic analysis option enabled were used for manufacturing process analysis and maintainability/human factors...
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This paper describes the extent to which flip chip packaging is advantageous to wirebond method on otherwise comparable chips. We discuss both the engineering reasons as to why flip chip packages should be faster and ...
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ISBN:
(纸本)081868433X
This paper describes the extent to which flip chip packaging is advantageous to wirebond method on otherwise comparable chips. We discuss both the engineering reasons as to why flip chip packages should be faster and the statistical method used to verify the engineering conclusions with planned experimental data about actual microprocessors. Electrical modeling predicted that the performance of the microprocessor would increase by 5-9% by converting the existing wire bond chip and packaging to a flip chip package. This result was verified using speed test and statistical analysis on electrically-matched chips. Median speed gain was 8.1%. This work illustrates how statisticians and engineers can complement each other in the product development phases.
SpecTRM is a systems engineering environment to support modeling and analysis during requirements generation, functional decomposition and tradeoff analysis, subsystem specification, implementation, verification, and ...
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SpecTRM is a systems engineering environment to support modeling and analysis during requirements generation, functional decomposition and tradeoff analysis, subsystem specification, implementation, verification, and system maintenance and evolution. A general goal is to build bridges among disciplines by providing integrated specifications and modeling tools that can be used by system engineers, software engineers, and human factors experts. Because many automated real-time systems have safety-critical aspects, SpecTRM provides support for hazard analysis and building safety into the design. The safety information and activities on a project are integrated into the development and decision making environment.
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