High throughput spatial convolution filters on FPGAs

Digital signal processing (DSP) on field- programmable gate arrays (FPGAs) has long been appealing because of the inherent parallelism in these computations that can be easily exploited to accelerate such algorithms. FPGAs have evolved significantly to further enhance the mapping of these algorithms, included additional hard blocks, such as the DSP blocks found in modern FPGAs. Although these DSP blocks can offer more efficient mapping of DSP computations, they are primarily designed for 1-D filter structures. We present a study on spatial convolutional filter implementations on FPGAs, optimizing around the structure of the DSP blocks to offer high throughput while maintaining the coefficient flexibility that other published architectures usually sacrifice. We show that it is possible to implement large filters for large 4K resolution image frames at frame rates of 30–60 FPS, while maintaining functional flexibility

Deep anterior lamellar keratoplasty for pellucid marginal degeneration

AbstractPurposeTo present the surgical outcomes of deep anterior lamellar keratoplasty (DALK) for pellucid marginal degeneration (PMD).MethodsA retrospective review was performed in 16 eyes of 16 patients who underwent DALK at the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia between January 1, 2006 and December 30, 2009. Baring of Descemet’s membrane (DM) during DALK was achieved in 8 (50%) eyes; residual stroma was left intraoperatively in the remaining 8 (50%) eyes. The big bubble technique was performed in 10 (62.5%) eyes and manual dissection was performed in the remaining 6 (37.5%) eyes. Visual acuity (LogMAR notation), intraocular pressure, intraoperative complications and postoperative graft status were assessed.ResultsThe mean follow up was 14.6±8.2months (range 6–35months). The mean overall age was 31.4±9.6years (range, 19–50years). Visual acuity increased statistically significantly from 0.9±0.3 (range 0.5–1.6) preoperatively to 0.4±0.2 (range 0.0–0.7) at last follow-up (p<0.0001). There was a statistically significant improvement in postoperative sphere, cylinder, and spherical equivalent (p<0.035, p<0.001, and p<0.02, respectively) compared to preoperative. Postoperative visual acuity was not statistically significantly related to gender, type of surgical technique, and baring or perforation of DM. The main graft-related complication was graft–host vascularization (2/16 eyes).ConclusionDALK reduces severe corneal astigmatism and results in good visual and refractive outcomes and is an effective alternative for patients with PMD

Airline schedule punctuality management

Airline schedule punctuality is a complex problem and one of the major concerns of the airline top management. Flight schedule disturbances may occur as delays and/or cancellations. There are many internal and external reasons for delays. These delays may propagate in the aircraft cycles and cause a large schedule disturbance. This may influences passenger satisfaction and airline resources. The objective of this research is to formulate a systematic approach for schedule punctuality which supports management decision making. The punctuality management system is structured to combine all schedule punctuality components, input and output variables. Five models are incorporated in this system. The first model is the disturbance model which generates random delays based on an estimated Lognormal delay distribution function. The delay analysis is carried out from a one year sample of delay statistics in which general, original , reactionary and other delay types are classified. The second model is the recovery model which incorporates the disturbance model with management strategies to determine delay propagation. A PC based simulation model (SKDMOD) is developed as a prototype which integrates disturbance and recovery models using SIMSCRIPT 11.5. 18 management strategies are simulated covering ground times (30, 40 and 50 minutes), maximum delay times to assign spare aircraft (1, 2, 3, 4, 5, and 6 hours) and spare aircraft using part of the domestic network of Saudi Arabia. The third model is the passengers' attitude model which determines the delay impact functions and the maximum passenger revenue loss based on 262 responses from a passenger interview survey. The fourth model is the revenue model which estimates the passengers' revenue loss. The fifth model is the cost model which estimates the extra cost resulting from implementation of the management strategies. All strategies are evaluated to determine the optimum based on profit and profit margin. OPTIM is the optimization program developed to find the optimum strategy(ies). This approach provides a guidelines for the management of punctuality. It integrates all the tools developed in a decision support system framework

MARKET STRUCTURE AND MORTGAGE PRICING: THE ROLE OF INFORMATION IN FIRM AND CONSUMER BEHAVIOR

This dissertation analyzes information, market structure, and firm pricing strate-gies. I begin the dissertation with an analysis of the market structure of the mortgage in-dustry. I find that the configuration of the mortgage market at its present state is vastly different than its historical structure. The reduction in the cost of transmitting informa-tion has increased the collaborative environment and facilitated the dis-integration of the supply chain. Generally, the mortgage industry has been successful at reducing principal-agent problems and minimizing asymmetric information concerns that arise in segmented markets. In the first essay I provide a theoretical explanation of the effect of the internet on market outcomes. Search models assume that the reduction in search frictions would lead to competitive markets. However, I argue that gatekeepers operating in online markets may create an anticompetitive effect, in addition to reducing the consumers’ search cost. Therefore, the conduct of the gatekeeper can cause prices in online markets to be higher than in retail markets and provide online firms with larger profits. In the second essay “I empirically examine the role of the internet and Internet Comparison Search sites in reducing consumer search costs and their effects on the prices consumers pay for mortgages. Additionally, I expand the study to test for the effects of the internet on firm profits. Using a unique data set, I examine a mortgage firm’s pricing strategies and profits in online and retail markets, and find evidence of market power in online markets that do not exist in retail markets. The presumed benefits to the consumer from the reduction of search cost are offset by the anticompetitive environment in online markets. In the final essay, I examine a mortgage firm’s portfolio choice. I investigate the loan characteristics that affect the firm’s decision to retain mortgages as part of its own portfolio. I find that the decision to retain loans as a lender is driven by unobservable qualities. The firm does sort loans by quality, but it also prices non-brokered loans lower based on unobservable qualities. The sorting behavior suggests that asymmetric information exists between the lender and the secondary market

Feasibility study on utilization of palm fibre waste into fired clay brick

Malaysia is the second largest of palm oil producer after Indonesia, which contribute to 50 % of palm oil production. With this demand, the increasing of palm oil plantation over the years has led to the large production of agricultural waste, for example palm fibre waste. This study investigates different percentages of palm fibre (0 %, 1 %, 5 % and 10 %) to be incorporated into fired clay brick. Manufactured bricks were fired at 1 °C/min heating rate up to 1050 °C. The effects of manufacture bricks on the physical and mechanical properties of manufactured brick were also determined. All brick samples were tested due to the physical and mechanical properties which include dry density, firing shrinkage, initial rate of suction (IRS), water absorption, porosity and compressive strength. Findings show that increasing palm fibre waste affected the properties of brick, which decreased their density, besides increased firing shrinkage, IRS, water absorption, porosity and compressive strength. However, all the manufactured brick still followed the requirement