A model for peak matrix performance on FPGAs

Computations involving matrices form the kernel of a large spectrum of computationally demanding applications for which FPGAs have actively been utilized as accelerators. The performances of such matrix operations on FPGAs are related to underlying architectural parameters such as computational resources, memory and I/O bandwidth. A model that gives bounds on the peak performance of matrix-vector and matrix-matrix multiplication operations on FPGAs based on these parameters is presented. The architecture and efficiency of existing implementations are compared against the model. Future trends in matrix performance on FPGA devices are estimated based on the performance model and system parameters from the past decade. © 2011 IEEE.published_or_final_versio

A soft coarse-grained reconfigurable array based high-level synthesis methodology: Promoting design productivity and exploring extreme FPGA frequency

Compared to the use of a typical software development flow, the productivity of developing FPGA-based compute applications remains much lower. Although the use of high-level synthesis (HLS) tools may partly alleviate this shortcoming, the lengthy low-level FPGA implementation process remains a major obstacle to high productivity computing, limiting the number of compile-debug-edit cycles per day. Furthermore, high-level application developers often lack the intimate hardware engineering experience that is needed to achieve high performance on FPGAs, therefore undermining their usefulness as accelerators. To address the productivity and performance problems, a HLS methodology that utilizes soft coarse-grained reconfigurable arrays (SCGRAs) as an intermediate compilation step is presented. Instead of compiling high-level applications directly to circuits, the compilation process is reduced to an operation scheduling task targeting the SCGRA. © 2013 IEEE.published_or_final_versio

A comparison of SAR image speckle filters

High quality images of Earth produced by synthetic aperture radar (SAR) systems have become increasingly available, however, SAR images are difficult to interpret. Speckle reduction remains one of the major issues in SAR imaging process, although speckle has been extensively studied for decades. Many reconstruction filters have been proposed and they can be classified into two categories: multilook and/or minimum mean-square error (MMSE) despeckling using the speckle model; and maximum a posteriori (MAP) or maximum likihood (ML) despeckling using the product model. The most well known Lee, Kuan, and Frost filters belong to first category. These filters are based on conventional techniques that were originally derived for stationary signals, such as MMSE. In the second category, filters are based on the product model, such as the MAP Gaussian filter and the Gamma filter, and require knowledge of the a priori probability density function. These filters force speckle to have nonstationary Gaussian or gamma distributed intensity mean. The speckle filtering is mainly Bayesian model fitting that optimizes the MAP criteria. Scene reconstruction is performed using an inversion of the ascending chain. An objective measure is required to compare the technical merits of these filters, and Shi et al. presented a comparison 15 years ago. In this paper, a brief introduction of speckle, product, and filter models is summarized. A review of some most widely used SAR image speckle filters is given. And stationary speckle filters, like Lee, Kuan, and Frost filters, and nonstationary speckle filters like Gamma MAP filter are studied. Despeckling results on stationary and nonstationary SAR image of these speckle filters are presented. © 2009 Copyright SPIE - The International Society for Optical Engineering.published_or_final_versio

Hole-transporting spirothioxanthene derivatives as donor materials for efficient small-molecule-based organic photovoltaic devices

Poster: no. 30Taking the advantages of the 3D structure and rigid spiro-conjugation, spirobifluorene and its derivatives are a benchmark class of p-type semiconductors in organic electronic devices because of their good charge-transporting properties. However, their low absorption coefficients within the visible spectrum render their application as photoactive materials in the fabrication of organic photovoltaic (OPV) devices. A new class of heterocyclic spirothioxanthene derivatives has been designed and synthesized by the functionalization of the spiro core with various triarylamine groups and the modification of the heteroatom of the spiro core. The photophysical, electrochemical and thermal properties of these spirothioxanthene derivatives have been fully characterized. Of particular interest, all of these compounds exhibit high hole mobilities of up to 10–3 cm2V–1s–1, as determined from thin film transistor measurement. More importantly, these spirothioxanthene derivatives are promising donor materials for the fabrication of high performance OPV devices. With a very low dopant concentration of 7 % doped into fullerene matrix, efficient small molecular-based OPV devices with high open-circuit voltage of 0.94 V and high power conversion efficiency of 5.40 % (the highest PCE of 5.46 %) have been realized. This demonstrates for the first time their application studies as photovoltaic donor materials in OPV devices.published_or_final_versio

Condições de segurança e saúde no trabalho dos colaboradores da Portimar

O presente estudo pretende dar um contributo para a reflexão sobre o impacto que a cultura nacional, organizacional e Segurança, Higiene e Saúde no Trabalho, têm nas percepções individuais de risco dos trabalhadores, perante as condições de trabalho e saúde, dado que as mesmas condicionam as suas atitudes e comportamentos, com impacto directo na sua saúde. A metodologia de trabalho utilizada, para esse fim, prendeu-se, com o estudo de caso em contexto real de trabalho, da empresa Portimar - Agência de Viagens e Turismo, Lda. O estudo envolveu a distribuição e preenchimento de um inquérito validado, designado de Inquérito Saúde e Trabalho (INSAT, 2010), aos trinta e quatro trabalhadores. A aplicação do INSAT permitiu promover a reflexão e envolvimento, dos trabalhadores da Portimar - Agência de Viagens e Turismo, Lda., acerca das suas condições de trabalho e saúde, constituindo o primeiro passo para o desenvolvimento de práticas e comportamentos que, aumentem a sua resiliência, ao nível da saúde ocupacional

The effect of magnetic nanoparticles on the morphology, ferroelectric, and magnetoelectric behaviors of CFO/P(VDF-TrFE) 0–3 nanocomposites

Author name used in this publication: J. X. ZhangAuthor name used in this publication: J. Y. DaiAuthor name used in this publication: C. L. SunAuthor name used in this publication: C. Y. LoAuthor name used in this publication: S. W. OrAuthor name used in this publication: H. L. W. Chan2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Exercise and other lifestyle habits of patients with type II diabetes mellitus in Jos, Nigeria

Background Diabetes mellitus is a chronic disorder with complications affecting millions of people worldwide. It has been projected that in the near future, it will affect people in the developing countries like Nigeria more than the developed world. Lifestyle modification including exercise is important in the management of this condition. The other lifestyle of patients with diabetes including cigarette smoking and alcohol ingestion also affects the glycaemic control and the development or worsening of complications in these patientsMethods This was a descriptive cross-sectional study carried out at the diabetes clinic of Jos University Teaching Hospital (JUTH) and a diabetes specialist clinic in Jos, North central Nigeria. Ninety patients with diabetes aged 18 years and above were recruited consecutively. Wheel chair bound patients, patients who had amputation in the past and patients who did not consent to the study were excluded from the study. Data was obtained using an interviewer administered questionnaireResults Fifty -four (60%) persons were males. The mean age was 56.8±11.5 years. 52.2 % participated in one form of exercise with 43 (91.5%) persons exercising for <150 minutes per week. The mean duration of exercise per week was 75.6 ±55.5 minutes. Those who exercised were younger, males and with lower HbA1c The . common form of exercise was walking. Barriers to exercise found include lack of time, pain/swelling in the legs, ill health and not knowing what exercise to do. Three (33.3%) out of the nine persons who took alcohol ingested it in significant amount and 1 (1.1%) person smoked cigarette.Conclusion The exercise habit of patients with diabetes in this environment is poor with some persons taking alcohol in significant quantity and smoking cigarette. Education and counseling of these patients therefore are important and should be done at every given opportunity.Key words: Diabetes mellitus, exercise, lifestyle habits

Copy number gain of granulin-epithelin precursor (GEP) at chromosome 17q21 associates with overexpression in human liver cancer

Background: Granulin-epithelin precursor (GEP), a secretory growth factor, demonstrated overexpression in various human cancers, however, mechanism remain elusive. Primary liver cancer, hepatocellular carcinoma (HCC), ranks the second in cancer-related death globally. GEP controlled growth, invasion, metastasis and chemo-resistance in liver cancer. Noted that GEP gene locates at 17q21 and the region has been frequently reported to be amplified in subset of HCC. The study aims to investigate if copy number gain would associate with GEP overexpression. Methods: Quantitative Microsatellite Analysis (QuMA) was used to quantify the GEP DNA copy number, and fluorescent in situ hybridization (FISH) was performed to consolidate the amplification status. GEP gene copy number, mRNA expression level and clinico-pathological features were analyzed. Results: GEP DNA copy number determined by QuMA corroborated well with the FISH data, and the gene copy number correlated with the expression levels (n = 60, r = 0.331, P = 0.010). Gain of GEP copy number was observed in 20% (12/60) HCC and associated with hepatitis B virus infection status (P = 0.015). In HCC with increased GEP copy number, tight association between GEP DNA and mRNA levels were observed (n = 12, r = 0.664, P = 0.019). Conclusions: Gain of the GEP gene copy number was observed in 20% HCC and the frequency comparable to literatures reported on the chromosome region 17q. Increased gene copy number contributed to GEP overexpression in subset of HCC. © Yung et al; licensee BioMed Central.published_or_final_versio

Lipid control and use of lipid-regulating drugs for prevention of cardiovascular events in Chinese type 2 diabetic patients: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>Dyslipidaemia is an important but modifiable risk factor of cardiovascular disease (CVD) in type 2 diabetes. Yet, the effectiveness of lipid regulating drugs in Asians is lacking. We examined the effects of lipid control and treatment with lipid regulating drugs on new onset of CVD in Chinese type 2 diabetic patients.</p> <p>Methods</p> <p>In this prospective cohort consisting of 4521 type 2 diabetic patients without history of CVD and naïve for lipid regulating treatment recruited consecutively from 1996 to 2005, 371 developed CVD after a median follow-up of 4.9 years. We used Cox proportional hazard regression to obtain the hazard ratios (HR) of lipids and use of lipid regulating drugs for risk of CVD.</p> <p>Results</p> <p>The multivariate-adjusted HR (95% confidence interval) of CVD in patients with high LDL-cholesterol (≥ 3.0 mmol/L) was 1.36 (1.08 - 1.71), compared with lower values. Using the whole range value of HDL-cholesterol, the risk of CVD was reduced by 41% with every 1 mmol/L increase in HDL-cholesterol. Plasma triglyceride did not predict CVD. Statins use was associated with lower CVD risk [HR = 0.66 (0.50 - 0.88)]. In sub-cohort analysis, statins use was associated with a HR of 0.60 (0.44 - 0.82) in patients with high LDL-cholesterol (≥ 3.0 mmol/L) and 0.49 (0.28 - 0.88) in patients with low HDL-cholesterol. In patients with LDL-cholesterol < 3.0 mmol/L, use of fibrate was associated with HR of 0.34 (0.12 - 1.00). Only statins were effective in reducing incident CVD in patients with metabolic syndrome [(HR = 0.58(0.42--0.80)].</p> <p>Conclusions</p> <p>In Chinese type 2 diabetic patients, high LDL-cholesterol and low HDL-cholesterol predicted incident CVD. Overall, patients treated with statins had 40-50% risk reduction in CVD compared to non-users.</p