Browsing by Subject "Yield"
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Item Automatic semiconductor wafer map defect signature detection using a neural network classifier(2010-12) Radhamohan, Ranjan Subbaraya; Ghosh, Joydeep; El-Hamdi, MohamedThe application of popular image processing and classification algorithms, including agglomerative clustering and neural networks, is explored for the purpose of grouping semiconductor wafer defect map patterns. Challenges such as overlapping pattern separation, wafer rotation, and false data removal are examined and solutions proposed. After grouping, wafer processing history is used to automatically determine the most likely source of the issue. Results are provided that indicate these methods hold promise for wafer analysis applications.Item Continuous canopy temperature as a tool for managing deficit irrigation(2012-12) Young, Andrew W.; Dotray, Peter A.; Mahan, James R.; Payton, Paxton R.Deficit irrigation is becoming a trend in agricultural lands with reduced water. With the declining water resources comes renewed interest in deficit irrigation strategies and enhanced management capabilities to provide water when and where it is needed. However, in the past, plant-monitoring capabilities to assess water status of the plant were very costly and labor intensive. The innovation in infrared thermometry systems has allowed for the technology to become smaller and more cost efficient. This investigation uses the established method of BIOTIC developed by research scientist at USDA/ARS. The BIOTIC method has been patented and licensed by a new technology startup company, Smartfield™, under the moniker Smartcrop™. The research conducted used the Smartcrop™ technology, which consists of wireless infrared sensors and base stations for recording data from sensors. This thesis focused on the 2009 and 2010 cotton growing seasons in the Lubbock area. Water and yield data were discussed and analyzed in detail along with other environmental data relevant to plant growth and yield. Analysis and discussion of large temperature data sets were conducted. Canopy temperature comparisons were made using the BIOTIC method along with air vs. canopy temperature comparisons and treatment temperature comparisons. Vapor pressure deficits were also discussed in detail for selected treatments over the growing seasons. Finally, daytime average canopy temperature comparisons provided accurate estimates of water through the plant as a predictor of yield.Item Designer Sorghum Combining the High Digestibility and Waxy Grain Traits of Sorghum for Improved Nutrition Bioethanol Beer Feed and Food Products(2012-07-16) Jampala, BabithaSorghum (Sorghum bicolor (L). Moench) is used for human consumption in parts of Africa and Asia and as an animal feed mainly in the U.S. Though sorghum grain contains higher amounts of protein than other cereal grains such as wheat and corn, it is not as readily available for enzyme degradation in humans and animals. Protein body matrices called kafirins surround the starch granules in sorghum. Because the protein is less digestible, the starch is also less digestible for biofuel production. However variation for this trait exists and the line P850029 has a higher protein digestibility compared to other normal grain sorghum lines. This increase in digestibility of protein is due to the rearrangement of the kafirins in the prolamin protein bodies where, the ?-kafirins are rearranged in the seed endosperm and the amount of ?-kafirin in the grain is also reduced. The assay to phenotype the HD trait is time consuming and unpredictable. So identifying a quantitative trait loci (QTL) controlling the protein digestibility trait in sorghum would be beneficial in breeding. A recombinant inbred lines (RILs) population derived from P850029 x ?Sureno?, were developed and used to map QTL regulating the protein digestibility trait. A single QTL was identified on chromosome 1 between Xtxp43 and Xtxp329. Validation of the identified QTL was done on heterogenous inbred families (HIFs). The results validate the same QTL identified on the RIL population on chromosome 1. Later the high digestibility trait (HD) was integrated with the Waxy trait in sorghum. The Waxy (WX) sorghums have starch completely in the form of amylopectin. The effect of endosperm type on ethanol yield and fermentation efficiencies was studied among HD, WX and HD-WX lines. The HD-WX lines fermented in a shorter time i.e. completed fermentation in 48 h and their fermentation efficiencies were also higher around 90%. The DDGS of the HD-WX lines also had lower residual starch content and 50% higher amino acid lysine content when compared to wildtype sorghum. Moreover, the relation between endosperm traits and grain yield in sorghum has not been fully explored. In this study, we compared the yield and yield components of four unique endosperm phenotypes, HD, WX, HD-WX and wildtype lines. A total of 100 F2:4 derived recombinant inbred lines population from a cross between Tx2907/P850029 were selected with 25 lines from each HD, WX, HD-WX and wild-type line were included in the study. These lines were grown in three replications in College Station and Halfway, Texas in a randomized complete block design. The results show that there are no significant differences in the grain yield.Item Effects of row spacing on diseases, herbicide persistence, and qualitative characteristics of peanut(Texas A&M University, 2005-08-29) Besler, Brent AlanField and greenhouse studies were conducted to assess the effects of row-spacing on diseases, weed control, herbicide persistence and plant development in peanut. Tebuconazole, when averaged across cultivars and row spacing, effectively controlled white mold (57%) and rust (58%). Azoxystrobin also controlled white mold (58%) and controlling rust (44%). Both fungicides reduced leaf spot severity in the conventional and twin rows when compared to untreated plots. Twin rows showed a 10% yield increase compared to the conventional planting. Both diclosulam and imazapic, when applied to twin rows at the full and reduced rate, provided better yellow nutsedge control than when applied to the conventional row. Twin rows yielded higher than the conventional rows when averaged across herbicides in one year. All full rate herbicide treatments enhanced yield over the untreated check. Diclosulam and imazapic treated soil sampled 60 DAP adversely affected all four crops. The advantage of planting peanuts in twin rows to reduce diclosulam and imazapic residual concentrations was not apparent. Georgia Green and Tamrun 96 planted in twin rows at three of the four locations in 1999 and 2000 yielded higher than peanuts planted in conventional rows. Yields were comparable to twin-row spacings that had higher plant densities. Georgia Green and Tamrun 96 planted in conventional rows, in most cases, had higher yields than narrow-rows. Measurements for plant diameter, pod distribution, and main stem length were higher with Tamrun 96 at most row spacings and planting densities compared to the respective Georgia Green planting densities and row spacings. Both cultivars when planted in twin or narrow rows at all planting densities did not enhance maturity when sampled late season. Georgia Green and Tamrun 96 when planted in conventional rows had the most pods/plant compared to the narrow and twin row spacing. No clear evidence was found to suggest that peanuts grown in narrow or twin rows increased white mold disease incidence. Grades for Georgia Green were higher than Tamrun 96 when planted in twin rows at the standard planting density. Tamrun 96 in twin rows at the standard planting density had a higher grade than when planted in conventional rows at the low planting density.Item Efficient vlsi yield prediction with consideration of partial correlations(2009-05-15) Varadan, SridharWith the emergence of the deep submicron era, process variations have gained importance in issues related to chip design. The impact of process variations is measured using manufacturing/parametric yield. In order to get an accurate estimate of yield, the parameters considered need to be monitored at a large number of locations. Nowadays, intra-die variations are an integral part of the overall process uctuations. This leads to the difficult case where yield prediction has to be done while considering independent and partially correlated variations. The presence of partial correlations adds to the existing trouble caused by the volume of variables. This thesis proposes two techniques for reducing the number of variables and hence the complexity of the yield computation problem namely - Principal Component Analysis (PCA) and Hierarchical Adaptive Quadrisection (HAQ). Systematic process variations are also included in our yield model. The biggest plus in these two methods is reducing the size of the yield prediction problem (thus making it less time complex) without affecting the accuracy in yield. The efficiency of these two approaches is measured by comparing with the results obtained from Monte Carlo simulations. Compared to previous work, the PCA based method can reduce the error in yield estimation from 17.1% - 21.1% to 1.3% - 2.8% with 4.6x speedup. The HAQ technique can reduce the error to 4.1% - 5.6% with 6x - 9.4x speedup.Item Evaluation of the genetic gain in upland cotton during the twentieth century(Texas A&M University, 2007-04-25) Schwartz, Brian MatthewGenetic gain studies in the past have been used to evaluate the historical improvement of different traits and give insight into what magnitudes of gain might be possible in the future. Additionally, they have been carried out to defend the role of genetics during periods of stagnant or decreasing yield trends. This study was conducted over a 2-year period (2003 and 2004) and included nine current or obsolete cotton (Gossypium hirsutum L.) cultivars grown in 5 plant densities designed to evaluate varying levels of interplant competition. Plant densities were single plant culture with plants spaced 3m x 3m, 2m x 2m, 1m x 1m, 1m x 0.3m, and two commercial populations with plants spaced 1m x 0.1m. Results were analyzed for each trait to determine whether genetic gains are interrelated with tolerance to interplant competition or strictly under genetic control. The rates of genetic gain for lint yield were highest in the 1m x 0.1m, 1m x 0.3m, and 1m x 1m treatment with slopes of 8.7, 8.2, and 7.1 kg ha-1 yr-1 respectively. The slopes were each significantly smaller in the 2m x 2m and 3m x 3m spaced populations with gains of 3.6 and 1.5 kg ha-1 yr-1 respectively, implying that for lint yield, genetic gains have been made for tolerance to interplant competition. Similarly, modern maize hybrids only out perform obsolete hybrids at higher plant densities. Genetic gain for lint yield, fiber length, fiber strength, and fiber micronaire made in the context of tolerance to interplant competition is due in large part to the excellent performance of Deltapine 491 (2002) at higher plant populations.Item Improving Maize by QTL Mapping, Agronomic Performance and Breeding to Reduce Aflatoxin in Texas(2012-07-16) Mayfield, Kerry LucasAflatoxins are potent carcinogens produced by the fungus Aspergillus flavus Link:Fr and are a significant preharvest problem in maize production in Texas, the southern US, and subtropical climates. Several sources of maize germplasm are available which reduce preharvest aflatoxin accumulation, but many of these sources lack agronomic performance for direct use as a parent in commercial hybrids. Tropical germplasm is a source of both resistance to aflatoxin accumulation resistance and agronomic performance traits. The goal of this study was to investigate germplasm for traits to reduce preharvest aflatoxin accumulation. The specific objectives of this research were: 1) to validate QTL estimates previously identified in lines per se and estimate new QTL associated with reduced aflatoxin accumulations and agronomic traits; 2) to evaluate agronomic characteristics of selections from a RIL population in testcrosses at multiple locations across Texas; and (3) to release agronomically desirable germplasm sources with reduced risk to preharvest aflatoxin accumulation. A total of 96 QTLs were detected across fourteen measured traits using an RIL population of 130 individuals in testcross hybrids evaluated in five environments. Three QTL detected in per se analyses were also detected in hybrid testcrosses. Previously unreported QTL were detected on chromosomes 3, 4, 8 and 9. Within each of the two years, neither subset of the RIL testcross hybrids produced grain yields equal to commercial hybrid checks in these trials, but one testcross in 2008 produced grain yield within 10 percent of commercial check hybrids and in 2009, five RIL testcrosses produced grain yield within 17 percent of the commercial check hybrids. Although RIL testcrosses did not yield more than the commercial checks, they will be a source of germplasm for reduced aflatoxin. Improved sources of maize germplasm lines Tx736, Tx739, and Tx740 have been selected for adaptation to southern US and Texas growing environments with traits that reduce aflatoxin accumulation. Each of the lines in testcross accumulated significantly fewer aflatoxins than commercial hybrids in the trial.Item Optimization and yield enhancement for measuring contact resistance in large scale microprocessors(2008-12) Reich, Jonathan R.; Nutter, Brian; Gale, Richard O.As semiconductor technology advances, the functionality and complexity of microprocessors increase. Establishing proper test methods is an important electrical characteristic of testing a DUT (Device Under Test). With a large scale microprocessor’s pin count exceeding one thousand, abstract methods must be used to insure proper test integration between the tester and DUT. Because the majority of tests performed on high-end microprocessors are complex and sensitive to noise, it is becoming more important that quality electrical connections are being made. The purpose of this thesis is to tighten CRes test limits so solder ball integrity can be verified to eliminate a test insertion from the production test flow. Previous CRes limits were relaxed due to complications while testing CRes. These complications and solutions will be addressed in this thesis. This thesis will describe methods of testing and optimization to enhance yield while testing contact resistance (CRes) on large pin count SUN Niagara 2 and Victoria Falls microprocessors using a LTX Fusion VX4/VX5 tester. This thesis will also discuss test methods to reduce mechanical error associated between the tester and the DUT.Item Physical and Chemical Characteristics of High-Tonnage Sorghum for an Extended Biomass Harvesting Season and Storage(2013-05-06) Hartley, BrandonIncreasing differences in United States energy consumption and production has influenced the passing of legislation for biomass fuel production. To determine feasibility of energy crops for alternative fuels, research is needed to investigate dry matter yield over an extended harvest season; physical characteristics need to be described for potential harvesting problems; chemical characteristics described to identify selective harvest potential, optimal harvest timing, losses during harvest and storage; various harvest techniques investigated to identify potential cost savings; and impact of various storage techniques on quantity and quality of deliverable biomass. This study investigated the use of two sorghum varieties as a potential bioenergy feedstock where 20 ha were planted for three years. Standing crop samples were collected from August through January to document changes in dry matter yield, moisture, height, fiber content, proximate and ultimate analysis. The sorghum was cut and conditioned ? as a two-cutting ratoon or single-cutting ? using various mower-conditioners and windrow samples taken daily to determine best method of field drying, quantify dry matter loss and soil entrainment. Two storage methods were utilized ? baling with wrapping in a tubeline, and chopping and compressing in bag using a modified cotton module builder ? to determine best method of storage for reduced dry matter loss. The optimal time of harvest for maximum dry matter occurred with the November once-cut where 30 Mg ha^-1 was documented, but comparable yields were observed with the two-cutting scenario. Fiber content increased with maturity, peaked, and declined, while ash content and moisture decreased with maturity. The achievement of 55% moisture in January shows field curing to be necessary for transportation at any significant distance, but soil entrainment ? as measured by ash concentration ? was not found to be a significant problem after conditioning, multiple windrow inversions, and harvesting. The geometric mean length of particle was determined to be 1.4 to 3.7 times lower than nominal chop length, indicating potential cost savings in comminution. Dry matter loss estimates during storage proved difficult due to mobility of moisture throughout the packages, where losses were documented up to 40%. Module packages tended to have lower dry matter and constituent losses than bales.Item Spatial and temporal variability in cotton yield in relation to soil apparent electrical conductivity, topography, and remote sensing imagery(Texas Tech University, 2005-12) Guo, Wenxuan; Maas, Stephan J.; Zartman, Richard E.; Bronson, Kevin F.; Segarra, Eduardo; Nagihara, SeiichiAnalysis of data from multiple fields over several years provides the ability to determine under what conditions precision agriculture may be suitable. The objectives of this study were to: a) evaluate the spatial variability in cotton (Gossypium hirsutum L.) yield; b) assess the temporal stability in cotton yield over different growing seasons; c) determine the spatial and temporal variability in cotton yield in relation to soil apparent electrical conductivity (ECa), terrain attributes, and bare soil brightness; d) delineate potential management zones based on ECa, terrain attributes, and bare soil brightness obtained from satellite images and evaluate the consistency of the management zones over different growing seasons. This study was conducted on eight commercially managed cotton fields on the Southern High Plains of Texas from 2000 to 2003. Yield data were collected using harvesters equipped with yield monitors and global positioning systems (GPS). Digital elevation data were collected using a real time kinematic (RTK) GPS system. Elevation, slope, and curvatures were derived from the digital elevation data. The Normalized difference vegetation index (NDVI) was derived from multiple in-season Landsat remote sensing images. Bare soil brightness was obtained from two pre-season Landsat remote sensing images. Three potential management zones for each field in each year were delineated using the k-means and the fuzzy c-means methods. Two fields with high spatial variability in yield and soil properties were temporally stable in relative yield distribution over the four years, while the other fields were not stable. Remote sensing images explained up to 70% of yield variability in fields with high variability in yield. The strongest relationship between yield and remote sensing images occurred in the middle of the growing seasons. Soil apparent electrical conductivity, terrain attributes, and bare soil brightness explained up to 81% of yield variability, which varied with fields and years. A greater amount of yield variability was explained in drier years than in wet years. Apparent electrical conductivity and bare soil brightness were more important in explaining yield variability than terrain attributes. Both k-means and fuzzy c-means were able to separate yield and the soil properties, but k-means tended to delineate more consistent and distinct management zones. Fields with higher variability in yield and soil properties tended to have more consistent management zones over different growing seasons. Based on the results from this study, soil apparent electrical conductivity and bare soil brightness appear to be the most important soil characteristics evaluated in this study for determining management zones in the Southern High Plains of Texas. Fields with high spatial variability in yield and soil conditions appear to be better suited for PA applications.Item Spatial and temporal variability in cotton yield in relation to soil apparent electrical conductivity, topography, and remote sensing imagery(2005-12) Guo, Wenxuan; Maas, Stephan J.; Zartman, Richard E.; Bronson, Kevin F.; Segarra, Eduardo; Nagihara, SeiichiAnalysis of data from multiple fields over several years provides the ability to determine under what conditions precision agriculture may be suitable. The objectives of this study were to: a) evaluate the spatial variability in cotton (Gossypium hirsutum L.) yield; b) assess the temporal stability in cotton yield over different growing seasons; c) determine the spatial and temporal variability in cotton yield in relation to soil apparent electrical conductivity (ECa), terrain attributes, and bare soil brightness; d) delineate potential management zones based on ECa, terrain attributes, and bare soil brightness obtained from satellite images and evaluate the consistency of the management zones over different growing seasons. This study was conducted on eight commercially managed cotton fields on the Southern High Plains of Texas from 2000 to 2003. Yield data were collected using harvesters equipped with yield monitors and global positioning systems (GPS). Digital elevation data were collected using a real time kinematic (RTK) GPS system. Elevation, slope, and curvatures were derived from the digital elevation data. The Normalized difference vegetation index (NDVI) was derived from multiple in-season Landsat remote sensing images. Bare soil brightness was obtained from two pre-season Landsat remote sensing images. Three potential management zones for each field in each year were delineated using the k-means and the fuzzy c-means methods. Two fields with high spatial variability in yield and soil properties were temporally stable in relative yield distribution over the four years, while the other fields were not stable. Remote sensing images explained up to 70% of yield variability in fields with high variability in yield. The strongest relationship between yield and remote sensing images occurred in the middle of the growing seasons. Soil apparent electrical conductivity, terrain attributes, and bare soil brightness explained up to 81% of yield variability, which varied with fields and years. A greater amount of yield variability was explained in drier years than in wet years. Apparent electrical conductivity and bare soil brightness were more important in explaining yield variability than terrain attributes. Both k-means and fuzzy c-means were able to separate yield and the soil properties, but k-means tended to delineate more consistent and distinct management zones. Fields with higher variability in yield and soil properties tended to have more consistent management zones over different growing seasons. Based on the results from this study, soil apparent electrical conductivity and bare soil brightness appear to be the most important soil characteristics evaluated in this study for determining management zones in the Southern High Plains of Texas. Fields with high spatial variability in yield and soil conditions appear to be better suited for PA applications.Item Techniques to minimize circuitry and improve efficiency for defect tolerance(2013-05) Rab, Muhammad Tauseef; Touba, Nur A.As technology continues to scale to smaller geometries and newer dimensions (3-D), with increasingly complex manufacturing processes, the ability to reliably manufacture 100% defect-free circuitry becomes a significant challenge. While implementing additional circuitry to improve yield is economically justifiable, this thesis addresses the cost of defect tolerance by providing lower cost solutions or alternatively more defect tolerance for the same cost in state-of-the-art ICs, including three-dimensional ICs (3-D ICs). Conventional defect tolerance techniques involve incorporating redundancy into the design. This thesis introduces novel designs to maximize the utility of spare elements with minimal circuitry overhead, thereby improving the yield. One idea proposed is Selective Row Partitioning (SRP), a technique which allows a single spare column to be used to repair multiple defective cells in multiple columns. This is done by selectively decoding the row address bits when generating the select signals for the column multiplexers. This logically segments the spare column allowing it to replace different columns in different partitions of the row address space. All the chips are identical, but fuses are used to customize the row decoding circuitry on a chip-by-chip basis. An implementation procedure and results are presented which show improvement in overall yield at a minimal overhead cost. Moreover, new yield-enhancing design techniques for 3-D ICs are introduced. When assembling a 3-D IC, there are several degrees of freedom including which die are stacked together, in what order, and with what rotational symmetry. This thesis describes strategies for exploiting these degrees of freedom to reduce the cost and complexity of implementing defect tolerance. One strategy is to enable asymmetric repair capability within a 3-D memory stack by exploiting the degree of freedom that the order of the die in the stack can be selected. This technique optimizes the number of fuses, and in some cases, the number of spares as well, required to implement defect tolerance. Another innovative technique is to exploit rotational symmetry of the dies to do implicit reconfiguration to implement defect tolerance. Results show that leakage power and performance overhead for defect tolerance can be significantly reduced by this technique.Item Yield improvement for analog to digital converter test(2007-05) Kamalapuri, Poorvaja; Parten, Michael E.; Nutter, Brian; Gale, Richard O.A yield of 99% is a very demanding yet achievable target in the semiconductor industry. High volumes and fierce competition call for constant yield management. Continual monitoring of trends and process improvements aim to achieve such high yields. This thesis outlines a systematic approach to problem solving intended to serve as a guide to diagnose and solve yield issues. It also helps identify dead-ends to make pragmatic decisions in view of return on investment. An example problem of yield loss of an Analog to Digital Converter test is discussed to illustrate the procedure. Further, the steps taken to bring its yield up to a satisfying figure are explained.