Abbas Rahimi

ABSTRACT This paper proposes a new model of functional units for variation-induced timing errors due to PVT variations and device Aging (PVTA). The model takes into account PVTA parameter variations, clock frequency, and the physical details of Placed-and-Routed (P&R) functional units in 45nm TSMC analysis flow. Using this model and PVTA monitoring circuits, we propose Hierarchically Focused Guardbanding (HFG) as a method to adaptively mitigate PVTA variations. We demonstrate the effectiveness of HFG on GPU architecture at two granularities of observation and adaptation: (i) fine-grained instruction-level; and (ii) coarse-grained kernel-level. Using coarse-grained PVTA monitors with kernel-level adaptation, the throughput increases by 70% on average. By comparison, the instruction-by-instruction monitoring and adaptation enhances throughput by a factor of 1.8×–2.1× depending on the configuration of PVTA monitors and the type of instructions executed in the kernels.

ABSTRACT Manufacturing and environmental variations cause timing errors in microelectronic processors that are typically avoided by ultra-conservative multi-corner design margins or corrected by error detection and recovery mechanisms at the circuit-level. In contrast, we present here runtime software support for cost-effective countermeasures against hardware timing failures during system operation. We propose a variability-aware OpenMP (VOMP) programming environment, suitable for tightly-coupled shared memory processor clusters, that relies upon modeling across the hardware/software interface. VOMP is implemented as an extension to the OpenMP v3.0 programming model that covers various parallel constructs, including ${tt task}$, ${tt sections}$, and ${tt for}$. Using the notion of work-unit vulnerability (WUV) proposed here, we capture timing errors caused by circuit-level variability as high-level software knowledge. WUV consists of descriptive metadata to characterize the impact of variability on different work-unit types running on various cores. As such, WUV provides a useful abstraction of hardware variability to efficiently allocate a given work-unit to a suitable core for execution. VOMP enables hardware/software collaboration with online variability monitors in hardware and runtime scheduling in software. The hardware provides online per-core characterization of WUV metadata. This metadata is made available by carefully placing key data structures in a shared L1 memory and is used by VOMP schedulerss. Our results show that VOMP greatly reduces the cost of timing error recovery compared to the baseline schedulers of OpenMP, yielding speedup of 3%–36% for tasks, and 26%–49% for sections. Further, VOMP reaches energy saving of 2%–46% and 15%&#x- 013;50% for tasks, and sections, respectively.

Perception of body-weight status is an important determinant of weight-related behaviours and may affect the burden of weight disturbances as a public-health problem. No study has assessed self-perception of the weight status regarding body-fat distribution among health workers to date. The aim of this study was to evaluate the association of the perception of weight and health status among 542 women working at health centres of Tehran. We assessed their perceived body-weight and health status and measured waist- and hip-circumference, weight, and height to calculate waist-to-hip ratio (WHR) as a measure of fat distribution and body mass index (BMI, kg/m2). Women reported their sociodemographic information, and the perceived weight and health status were compared with their actual fatness status, defined based on WHR and BMI, to determine misperception of weight status. Multivariate logistic regression models were performed to assess the predictive effects of various sociodemographi...

Attention-deficit/hyperactivity disorder (ADHD) is associated with difficulties in learning, behaviour and psychosocial adjustment that persist into adulthood. Decreased omega-3 fatty acids and increased inflammation or oxidative stress may contribute to neuro-developmental and psychiatric disorders such as ADHD. The aim of this study was to determine the effect of n-3 supplementation on hyperactivity, oxidative stress and inflammatory mediators in children with ADHD. In this double blind study, 103 children (6-12 years) with ADHD receiving maintenance therapy were assigned randomly into two groups. The n-3 group received n-3 fatty acids (635 mg eicosapentaenoic acid (EPA), 195 mg docosahexaenoic acid (DHA)), and the placebo group received olive oil capsules which were visually similar to the n-3 capsules. The duration of supplementation was 8 weeks. Plasma C-reactive protein (CRP), interleukin-6 (IL-6) and the activity of glutathione reductase (GR), catalase (CAT) and superoxide di...

Visual sciences have been progressing quickly in recent decades through globalization phenomenon. An enormous change has taken place in ocular health issues, however, there are various problems facing ophthalmic public health worldwide. In the previous years, the World Health Organization and the International Agency for the Prevention of Blindness in partnership launched the global initiative to eradicate avoidable blindness by the year 2020, VISION 2020 the Right to Sight. It has concentrated on the prevention of blindness disability and recognized a health issue-sight as a human right. In view of challenges ahead of visual sciences, close collaboration between international agencies at the global level to implement new strategies and monitor the progress will be mandatory. In these circumstances non-governmental organizations should not be neglected. World Sight Day 2012 would be a great opportunity to be a focus on importance of visual impairment as an important public health is...

Excretion of carbon dioxide and L-lactic acid through exhalation and perspiration provides olfactory signals to mosquitoes which allow them to find and bite humans; however, mosquito species differ in this regard. This study investigated upwind responses of Anopheles stephensi, mysorensis form, an important malaria vector in Asia, to carbon dioxide and L-lactic acid under laboratory conditions. While a minimal dose of carbon dioxide (90 ppm) activated the mosquitoes, 10 times this amount suppressed them. L-lactic acid alone did not produce a significant effect by itself, but addition of 6 microg/min of L-lactic acid to a range of 90 to 410 ppm carbon dioxide resulted in attraction. The results provide further support for the hypothesis that CO2 plays an important role in the host-seeking behaviour of zoophilic mosquitoes, and suggests that L-lactic acid might play a more critical role than CO2 in the attraction of An. stephensi.

The Islamic Republic of Iran is in the pre-elimination phase of malaria control, but malaria epidemics are still a concern in the south of the country. This retrospective study presents the epidemiological characteristics and predisposing factors of 60 of the malaria epidemics reported in Sistan va Baluchestan province during 2005-09. A zero-truncated negative binomial model was used to investigate the relation between predictor variables and the total number of malaria cases. Malaria epidemics occurred mainly in the southern part of the province, mostly between July and October, peaking in August. Most malaria epidemics were small-scale (68.3% were < 100 cases) and short (51.7% lasted < 1 month). Plasmodium falciparum was present in 46.7% of the epidemics. An increase in the rainfall rate as well as population movements were the most significant predisposing factors. The results may help inform an epidemic investigation and reporting system as the country approaches the malar...

Patient empowerment can enhance the outcomes of care such as metabolic control as well as quality of their life. This study evaluates the Iranian version for development of a valid and reliable diabetes empowerment scale. Validity and reliability of Iranian version of Diabetes Empowerment Scale (DES-LF) were measured through a cross-sectional study. DES-LF was evaluated through a qualitative and quantitative study by 160 type 2 diabetic patients. Reliability and validity of the scale and its 3 subscales, namely, managing the psychosocial aspects of diabetes (α=0.94), assessing dissatisfaction and readiness to change (α=0.96), and setting and achieving diabetes goals (α=0.96) were approved by a psychometric analysis. Findings approved the reliability and validity of the Iranian version of DES-LF for patient education and psychosocial interventions among Iranian people with type 2 diabetes.

Successful gene delivery to the lung depends not only on precise and effective design of a nanosized nucleic acid delivery system but also on well engineered liquid or solid microparticles. In present work, we tried to statistically optimize spray dried formulations of low molecular weight chitosan-plasmid nanocomplexes via a D-optimal design with respect to five critical responses: yield of the process, microparticle sizes, nanocomplex sizes, DNA stability and relative transfection efficiency. Nonocomplex formulations prepared by different amounts of solid contents and leucine ratio, and spray dried immediately with varying inlet temperature, feed rate and spray air flow rate. Mean results fitted to 2FI models except for relative transfection efficiency, which fitted in a quadratic model. According to the fitted models, the most important pure factors influencing each response determined to be feed rate for yield and DNA stability, feed fluid concentration for microparticle size, i...

Despite an elevated obesity risk in people with spinal cord injury (SCI), investigation on the effects of age, obesity predictors, and injury related factors is yet to be unknown within the SCI population. Obesity predictors were measured in 162 patients. 27.5% of the participants were overweight and 5.6% of them were obese. Mean BMI was different between patients with tetraplegia and paraplegia (p < 0.01). More than 20% of participants had central obesity, significantly patients with higher age and time since injury. Significant positive relationship was found between level of injury and BMI. Participants with higher age and time since injury had higher waist circumference.

ABSTRACT We propose a tightly-coupled, multi-core cluster architecture with shared, variation-tolerant, and accuracy-reconfigurable floating-point units (FPUs). The resilient shared-FPUs dynamically characterize FP pipeline vulnerability (FPV) and expose it as metadata to a software scheduler for reducing the cost of error correction. To further reduce this cost, our programming and runtime environment also supports controlled approximate computation through a combination of design-time and runtime techniques. We provide OpenMP extensions (as custom directives) for FP computations to specify parts of a program that can be executed approximately. We use a profiling technique to identify tolerable error significance and error rate thresholds in error-tolerant image processing applications. This information guides an application-driven hardware FPU synthesis and optimization design flow to generate efficient FPUs. At runtime, the scheduler utilizes FPV metadata and promotes FPUs to accurate mode, or demotes them to approximate mode depending upon the code region requirements. We demonstrate the effectiveness of our approach (in terms of energy savings) on a 16-core tightly-coupled cluster with eight shared-FPUs for both error-tolerant and general-purpose error-intolerant applications.

Abstract: Background and Aims: The evaluation of absorbed dose received by patients could give useful information for radiation risk estimation. This study was performed to compare the entrance skin dose received by patients in cone beam computed tomography (CBCT), conventional and spiral computed tomography (CT). Materials and Methods: In this experimental study, 81 calibrated TLD chips were used. the TLD chips were placed on facial, thyroid and end of sternum skin surface in patients referred for CT of the paranasal ...

Page 1. 1 < < > @ < 2 <> < > < 3 > < < > < 4 > < > <@ Email: jalalikh@sina. tums.ac.ir 952 > – 29 / 148 / 1390 > / 148/ 1390 > : 5/2/90 : 1/4/90 25 D @ > > > 2 > > @ 1 < > > 2 < > @ 3 < > @ 2 < > 4 : > D > > > @ > ...

... Abbas Rahimi 1, Elham Kazemi 1, Ebrahim Khajeh 2, Hamidreza Mahboobi 3, 4, Asal Arab 5,Tahereh Khorgoei 6, 7, Fatemeh Hafezipour6, 7 1 ... Journal of Rafsanjan University of Medical Sciences 2006;4-B(4): 286-293 3. Mousavi SM, Montazeri A, Mohagheghi MA, Jarrahi AM ...

To evaluate the effects of soil fertilizing treatments on agro morphological traits and mucilage of Isabgol, a glasshouse experiment was conducted in College of Agronomy and Animal Sciences, University of Tehran. The experiment was conducted as a factorial based on ...

To evaluate the effects of soil fertilizing treatments on agro morphological traits and mucilage of Isabgol, a glasshouse experiment was conducted in College of Agronomy and Animal Sciences, University of Tehran. The experiment was conducted as a factorial based on ...