The viability of using pulsed laser excited Raman spectroscopy as a method for diamond detection from ore, has been investigated. In this method the spontaneous Stokes Raman signal is used as indicator of diamond, and a dual channel system is necessary for correcting for fluorescence of minerals and diamond itself. Various pulsed laser wavelengths from 266 to 1064nm were used, as well as cw lasers for comparison. Wavelength scans of the regions of interest, indicated that pulsed lasers at 532, 355 and 308nm may be used with confidence for this purpose. Mineral fluorescence did not appear to pose a threat to the method, but rather own fluorescence of some types of diamonds. In this respect, pulsed lasers offer a decided advantage above cw, due to nonlinear increase of fluorescence with laser power, resulting in superior Raman to fluorescence signal ratios. An apparatus constructed for discriminating diamond from ore was evaluated, and using minerals commonly occurring in diamond carrying ore as well as a wide variety of diamonds, it proved to function effectively. A significant improvement in the capability for diamond detection was found when pulsed lasers at 532 and 308nm were used, in comparison to the 532nm cw laser.

The viability of using pulsed laser excited Raman spectroscopy as a method for diamond detection from ore, has been investigated. In this method the spontaneous Stokes Raman signal is used as indicator of diamond, and a dual channel system is necessary for correcting for fluorescence of minerals and diamond itself. Various pulsed laser wavelengths from 266 to 1064nm were used, as well as cw lasers for comparison. Wavelength scans of the regions of interest, indicated that pulsed lasers at 532, 355 and 308nm may be used with confidence for this purpose. Mineral fluorescence did not appear to pose a threat to the method, but rather own fluorescence of some types of diamonds. In this respect, pulsed lasers offer a decided advantage above cw, due to nonlinear increase of fluorescence with laser power, resulting in superior Raman to fluorescence signal ratios. An apparatus constructed for discriminating diamond from ore was evaluated, and using minerals commonly occurring in diamond carrying ore as well as a wide variety of diamonds, it proved to function effectively. A significant improvement in the capability for diamond detection was found when pulsed lasers at 532 and 308nm were used, in comparison to the 532nm cw laser.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 179-182).

Sorting is often computationally intensive and can cause the application in which it is used to run slowly. To date, the quickest software sorting implementations for an N element sorting problem runs at O(nlogn). Current techniques, beyond developing better algorithms, used to accelerate sorting include the use of multiple processors or moving the sorting operation to a GPU. The use of multiple processors or a GPU can lead to increased energy consumption and heat produced by the device as compared to a single-core GPU-less implementation. To address these problems, specialized instructions and hardware units can be added to the processors to accelerate the sorting operation directly. This thesis studies and records the performance implications from implementing a sorting accelerator into a modern RISC-V processor pipeline. This thesis also explores the additional energy and area costs of implementing such hardware units in the processor.

Advances in recording technologies now allow us to record populations of neurons simultaneously, data necessary to understand the network dynamics of the brain. Extracellular probes are fabricated with ever greater numbers of recording sites to capture the activity of increasing numbers of neurons. However, the utility of this extracellular data is limited by an initial analysis step, spike sorting, that extracts the activity patterns of individual neurons from the extracellular traces. Commonly used spike sorting methods require manual processing that limits their scalability, and errors can bias downstream analyses. Leveraging the replication of the activity from a single neuron on nearby recording sites, we designed a spike sorting method consisting of three primary steps: (1) a blind source separation algorithm to estimate the underlying source components, (2) a spike detection algorithm to find the set of spikes from each component best separated from background activity and (3) a classifier to evaluate if a set of spikes came from one individual neuron. To assess the accuracy of our method, we simulated multi-electrode array data that encompass many of the realistic variations and the sources of noise in in vivo neural data. Our method was able to extract individual simulated neurons in an automated fashion without any errors in spike assignment. Further, the number of neurons extracted increased as we increased recording site count and density. To evaluate our method in vivo, we performed both extracellular recording with our close-packed probes and a co-localized patch clamp recording, directly measuring one neuron’s ground truth set of spikes. Using this in vivo data we found that when our spike sorting method extracted the patched neuron, the spike assignment error rates were at the low end of reported error rates, and that our errors were frequently the result of failed spike detection during bursts where spike amplitude decreased into the noise. We used our in vivo data to characterize the extracellular recordings of burst activity and more generally what an extracellular electrode records. With this knowledge, we updated our spike detector to capture more burst spikes and improved our classifier based on our characterizations.

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This thesis presents a new cascaded iterative VLSI sorting architecture that can accelerate data sorting of variable-length sequences. The proposed sorter mainly consists of a central data memory block, a core comparison unit, and a special address generation module. Many fast sorting algorithms can be represented by a network of compare-and-swap (C&S) operations which can be divided into several processing steps. Instead of using parallel C&S functional units to perform C&S operations of the same sorting step, our comparison unit is composed of cascaded C&S units connected through data commutator such that different sorting steps can be processed simultaneously. The advantage of cascaded architecture is that the number of data memory accesses can be reduced by a factor equal to the number of cascaded stages. However, how to reduce the overhead of the data commutator becomes the most critical design issue. This thesis has explored the feature of C&S operation order in Bitonic sorting such that much simpler and more regular data commutator module can be achieved compared with the previous cascade design derived based on Batcher sorting. Therefore, the cascade level of our sorter architecture can be more than 2. A sample of 4-level cascade sorter has been implemented in our thesis. To generate the address sequence suitable for the proposed cascaded comparison unit, this paper proposes a low-cost address generator design based on the bit-permutation technique. Although high cascade level can lead to significant reduction of memory access which can help reducing the power dissipation, the issues of low hardware utilization for short data sequences and the increasing commutator overhead cannot be neglected. Therefore, to achieve further speed-up, this paper also adopts another parallelism approach for data sorter design by utilizing block-level C&S units which can compare a block of data at the same time. The block-level C&S units can be designed based on traditional Batcher¡¦s sorting network. Based on the proposed Bitonic cascade and Batcher¡¦s block sorting approaches, very fast and low-power sorter hardware can be achieved.

Sorting is the problem of assignment of alternatives into predefined ordinal classes according to multiple criteria. A new distance function based solution approach is developed for sorting problems in this study. The distance to the ideal point is used as the criteria disaggregation function to determine the values of alternatives. These values are used to sort them into the predefined classes. The distance function is provided in general distance norm. The criteria disaggregation function is determined according to the sample preference set provided by decision maker. Two mathematical models are used in order to determine the optimal values and assign classes. The method also proposes an approach for handling alternative opt imal solutions, which are widely seen in sorting problems. Probabilities of belonging to each class for an alternative are calculated using the alternative optimal solutions and provided as the outputs of the model. Decision maker assigns the alternatives into classes according to these probabilities. The method is applied to five data sets and results are provided for different performance measures. Different distance norms are tried for each data set and their performances are evaluated for each data set. The probabilistic approach is also applied to UTADIS. The performance of the distance based model and modified UTADIS are compared with the previous sorting methods such as UTADIS and classification tree. The developed method has new aspects such as using distances to ideal point for sorting purpose and providing probabilities of belonging to classes. The handling of alternative optimal solutions within the method instead of a post-optimality analysis is another new and c ritical aspect of the study.

In this thesis existing models of adaptive computer architecture were modified to adapt actual sorting problems to "divide 'n' conquer" (DQ) coordinator type configuration in which the children processors were expanded from three to four. Two hire/fire strategies, one using packets waiting in queue and the other using the average turn around time, were applied to maintain the hierarchical tree structure. More than 1200 simulation runs were analyzed and compared, finding that the first strategy was best at fast packet arrival rate and the second strategy was best at slow packets arrival rate. Comparing the hire/fire signal generation policies, the "fc-root" was best and the "root-fp" was worst. While comparing the effect of variable weighting factors in processors, using smaller weighting factor in either "partitioner" for the first strategy or "f-computer" for the second strategy may improve the system performance. (Abstract shortened with permission of author.)