Application of error diffusion in Fourier transform cell-oriented holograms to compensate for printability constraints

Error diffusion is well-known adaptive quantization technique used in halftoning for quantizing data from a larger to a smaller number of gray levels. A method for creating cell-oriented computergenerated holograms using a modified error diffusion approach is proposed. Error diffusion is also a flexible tool for incorporating constraints of the printing device into the calculation of cell-oriented CGHs. The advantage of the proposed scheme is that the printability constraints are not applied in the calculation of the complex wave amplitude, but are incorporated in the subsequent quantization step for the CGH. The robustness of the quantization process has been investigated for varying aperture sizes, quantization conditions, and printer characteristics. The ability of error diffusion to reconstruct objects without adding a random phase and using a form of nonuniform quantization is also discussed

Heat transfer measurements for Stirling machine cylinders

The primary purpose of this study was to measure the effects of inflow-produced heat turbulence on heat transfer in Stirling machine cylinders. A secondary purpose was to provide new experimental information on heat transfer in gas springs without inflow. The apparatus for the experiment consisted of a varying-volume piston-cylinder space connected to a fixed volume space by an orifice. The orifice size could be varied to adjust the level of inflow-produced turbulence, or the orifice plate could be removed completely so as to merge the two spaces into a single gas spring space. Speed, cycle mean pressure, overall volume ratio, and varying volume space clearance ratio could also be adjusted. Volume, pressure in both spaces, and local heat flux at two locations were measured. The pressure and volume measurements were used to calculate area averaged heat flux, heat transfer hysteresis loss, and other heat transfer-related effects. Experiments in the one space arrangement extended the range of previous gas spring tests to lower volume ratio and higher nondimensional speed. The tests corroborated previous results and showed that analytic models for heat transfer and loss based on volume ratio approaching 1 were valid for volume ratios ranging from 1 to 2, a range covering most gas springs in Stirling machines. Data from experiments in the two space arrangement were first analyzed based on lumping the two spaces together and examining total loss and averaged heat transfer as a function of overall nondimensional parameter. Heat transfer and loss were found to be significantly increased by inflow-produced turbulence. These increases could be modeled by appropriate adjustment of empirical coefficients in an existing semi-analytic model. An attempt was made to use an inverse, parameter optimization procedure to find the heat transfer in each of the two spaces. This procedure was successful in retrieving this information from simulated pressure-volume data with artificially generated noise, but it failed with the actual experimental data. This is evidence that the models used in the parameter optimization procedure (and to generate the simulated data) were not correct. Data from the surface heat flux sensors indicated that the primary shortcoming of these models was that they assumed turbulence levels to be constant over the cycle. Sensor data in the varying volume space showed a large increase in heat flux, probably due to turbulence, during the expansion stroke

Automatic Generation of Data Flow Diagrams From A Requirements Specification Language

Escalating manpower costs in developing systems has caused an increasing need for greater productivity in system development particularly in the analysis and design phases. Productivity in the system analysis phase can be increased with the use of computer- aided tools such as SPSL/SPSA for specifying system requirements and methodologies such as structured analysis. A structured analysis and documentation tool-the data flow diagram-allows an analyst to model and document a system with relative ease; however, the manual production of a data flow diagram is a time consuming process Combining the production of data flow diagrams with SPSL/SPSA produces a synergistic effect on the increases in productivity and ensures the use of standards andthe completenessof the diagram. This paperdescribes the problems and design of the systemMONDRIAN that generates data flow diagrams from an SPSA database. A variety of placement and routing algorithms that address the layout problem are discussed. The results of a preliminary study of the effectiveness of these algorithms and the adaptations required to improve and refine the prototype version of MONDRIAN are presented

Experimental investigation of the Horizontal-to-Vertical Spectral Ratio (HVSR) method for estimating depth of bedrock in Central Missouri

[EMBARGOED UNTIL 6/1/2023] Determining the depth to bedrock is important in geotechnical site investigations, especially for foundation, slope stability, and settlement problems. Although methods such as drilling can be used to determine the depth to bedrock, geophysical methods are excellent supplemental tools to fill in the space between borings. However, many geophysical methods require extensive equipment to deploy and expertise to interpret the data. A recent, simple method to estimate the depth to bedrock is the Horizontal-to-Vertical Spectral Ratio (HVSR) method, which is a single-station measurement that only requires ambient noise and can be easily deployed and completed by a single person within 15 minutes. The objective of this study is to determine if a reliable relationship of depth to bedrock could be developed for the University of Missouri (MU) campus using the HVSR method alone without shear wave velocity measurements. In total, 65 HVSR measurements were performed around the MU campus over an approximate area of 1,200,000 m2. Measurements were performed with a three-component geophone, hand-held data acquisition system, and laptop computer. Relationships were developed between HVSR frequency versus depth to bedrock for all data and subsets of data based on the bedrock conditions. The results showed a reliable relationship can be developed for soil over limestone profiles, where the average errors were within 12 percent, which is consistent with similar past studies. However, when shale was present, the bedrock depth predictions were unreliable with errors as large 58 percent. Therefore, in practice, the HVSR relationship developed in this study should only be used at sites where shale is known to be absent, based on supplemental information. The HVSR relationship developed in this study was applied at a major construction project near the University of Missouri campus and showed good agreement between the prediction from HVSR and refraction results performed by another contractor. The errors in the depth predictions were within the range of 0.5 to 3.2 ft.Includes bibliographical references

On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices