Abstract-This paper proposes a two-phase scheme for removing salt-and-pepper impulse noise. In the first phase, an adaptive median filter is used to identify pixels which are likely to be contaminated by noise (noise candidates). In the second phase, the image is restored using a specialized regularization method that applies only to those selected noise candidates. In terms of edge preservation and noise suppression, our restored images show a significant improvement compared to those restored by using just nonlinear filters or regularization methods only. Our scheme can remove salt-and-pepper-noise with a noise level as high as 90%.Index Terms-Adaptive median filter, edge-preserving regularization, impulse noise.

Background Elderly-onset inflammatory bowel disease (IBD), defined as age ≥60 at diagnosis, is increasing worldwide. We aimed to compare clinical characteristics and natural history of elderly-onset IBD patients to adult-onset IBD patients. Methods Patients with a confirmed diagnosis of IBD from 1981 to 2016 were identified from a territory-wide Hong Kong IBD registry involving 13 hospitals. Demographics, comorbidities, clinical features and outcomes of elderly-onset IBD patients were compared to adult-onset IBD patients. Results A total of 2413 patients were identified, of whom 270 (11.2%) had elderly-onset IBD. Median follow-up duration was 111 months (Interquartile range [IQR]: 68-165 months). Ratio of ulcerative colitis (UC): Crohn’s disease (CD) was higher in elderly-onset IBD than adult-onset IBD patients (3.82:1 vs. 1.39:1; p&0.001). Elderly-onset CD had less perianal involvement (5.4% vs. 25.4%; p&.001) than adult-onset. Elderly-onset IBD patients had significantly lower cumulative use of immunomodulators (p=0.001) and biologics (p=0.04). Elderly-onset IBD was associated with higher risks of cytomegalovirus colitis (Odds ratio [OR]: 3.07; 95% Confidence Interval (CI) 1.92-4.89; p&0.001); herpes zoster (OR: 2.42; 95% CI: 1.22-4.80; p=0.12) and all cancer development (Hazard ratio: 2.97; 95% CI: 1.84-4.79; p&0.001). They also had increased number of overall hospitalization (OR: 1.14; 95% CI 1.09-1.20; p&0.001), infections-related hospitalization (OR: 1.87; 95% CI 1.47-2.38; p&0.001) and IBD-related hospitalization (OR: 1.09; 95% CI: 1.04- 1.15; p=0.001) compared to adult-onset IBD. Conclusion Elderly-onset IBD patients were associated with increased risk of infections, cancer development and increased infections- and IBD-related hospitalizations. Specific therapeutic strategies to target this special population is needed.

This paper describes a novel hardware accelerator for Monte Carlo (MC) simulation, and illustrates its implementation in field programmable gate array (FPGA) technology for speeding up financial applications. Our accelerator is based on a generic architecture, which combines speed and flexibility by integrating a pipelined MC core with an on-chip instruction processor. We develop a generic number system representation for determining the choice of number representation that meets numerical precision requirements. Our approach is then used in a complex financial engineering application, involving the Brace, Gatarek and Musiela (BGM) interest rate model for pricing derivatives. We address, in our BGM model, several challenges including the generation of Gaussian distributed random numbers and pipelining of the MC simulation. Our BGM application, based on an off-the-shelf system with a Xilinx XC2VP30 device at 50 MHz, is over 25 times faster than software running on a 1.5 GHz Intel Pentium machine.

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Abstract-Recently, a two-phase scheme for removing saltand-pepper impulse noise has been proposed [14]. In the first phase, an adaptive median filter is used to identify pixels which are likely to be contaminated by noise (noise candidates). In the second phase, the image is restored by minimizing a specialized regularization functional that applies only to those selected noise candidates. As an extension of this work, we propose an efficient method to accomplish the second phase. The speed of our method can be double as that of the method proposed in [14] for images contaminated by 30% salt-and-pepper noise and will be faster for higher noise level.