Exploiting dynamic timing margins in microprocessors for frequency-over-scaling with instruction-based clock adjustment

Static timing analysis provides the basis for setting the clock period of a microprocessor core, based on its worst-case critical path. However, depending on the design, this critical path is not always excited and therefore dynamic timing margins exist that can theoretically be exploited for the benefit of better speed or lower power consumption (through voltage scaling). This paper introduces predictive instruction-based dynamic clock adjustment as a technique to trim dynamic timing margins in pipelined microprocessors. To this end, we exploit the different timing requirements for individual instructions during the dynamically varying program execution flow without the need for complex circuit-level measures to detect and correct timing violations. We provide a design flow to extract the dynamic timing information for the design using post-layout dynamic timing analysis and we integrate the results into a custom cycle-accurate simulator. This simulator allows annotation of individual instructions with their impact on timing (in each pipeline stage) and rapidly derives the overall code execution time for complex benchmarks. The design methodology is illustrated at the microarchitecture level, demonstrating the performance and power gains possible on a 6-stage OpenRISC in-order general purpose processor core in a 28nm CMOS technology. We show that employing instruction-dependent dynamic clock adjustment leads on average to an increase in operating speed by 38% or to a reduction in power consumption by 24%, compared to traditional synchronous clocking, which at all times has to respect the worst-case timing identified through static timing analysis.

Protocol-driven adjustment of ocular hypotensive medication in patients at low risk of conversion to glaucoma

AIM: To investigate the safety and potential savings of decreasing medication use in low-risk patients with ocular hypertension (OH).
METHODS: Patients with OH receiving pressure-lowering medication identified by medical record review at a university hospital underwent examination by a glaucoma specialist with assessment of visual field (VF), vertical cup-to-disc ratio (vCDR), central corneal thickness and intraocular pressure (IOP). Subjects with estimated 5-year risk of glaucoma conversion <15% were asked to discontinue ≥1 medication, IOP was remeasured 1 month later and risk was re-evaluated at 1 year.
RESULTS: Among 212 eyes of 126 patients, 44 (20.8%) had 5-year risk >15% and 14 (6.6%) had unreliable baseline VF. At 1 month, 15 patients (29 eyes, 13.7%) defaulted follow-up or refused to discontinue medication and 11 eyes (5.2%) had risk >15%. The remaining 69 patients (107 eyes, 50.7%) successfully discontinued 141 medications and completed 1-year follow-up. Mean IOP (20.5±2.65 mm Hg vs 20.3±3.40, p=0.397) did not change, though mean VF pattern SD (1.58±0.41 dB vs 1.75±0.56 dB, p=0.001) and glaucoma conversion risk (7.31±3.74% vs 8.76±6.28%, p=0.001) increased at 1 year. Mean defect decreased (-1.42±1.60 vs -1.07±1.52, p=0.022). One eye (0.47%) developed a repeatable VF defect and 13 eyes (6.1%) had 5-year risk >15% at 1 year. The total 1-year cost of medications saved was US$4596.
CONCLUSIONS: Nearly half (43.9%) of low-risk OH eyes in this setting could safely reduce medications over 1 year, realising substantial savings.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Nuclear cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors.

PURPOSE: To quantify the association between siblings in age-related nuclear cataract, after adjusting for known environmental and personal risk factors. METHODS: All participants (probands) in the Salisbury Eye Evaluation (SEE) project and their locally resident siblings underwent digital slit lamp photography and were administered a questionnaire to assess risk factors for cataract including: age, gender, lifetime sun exposure, smoking and diabetes history, and use of alcohol and medications such as estrogens and steroids. In addition, blood pressure, body mass index, and serum antioxidants were measured in all participants. Lens photographs were graded by trained observers masked to the subjects' identity, using the Wilmer Cataract Grading System. The odds ratio for siblings for affectedness with nuclear cataract and the sibling correlation of nuclear cataract grade, after adjusting for covariates, were estimated with generalized estimating equations. RESULTS: Among 307 probands (mean age, 77.6 +/- 4.5 years) and 434 full siblings (mean age, 72.4 +/- 7.4 years), the average sibship size was 2.7 per family. After adjustment for covariates, the probability of development of nuclear cataract was significantly increased (odds ratio [OR] = 2.07, 95% confidence interval [CI], 1.30-3.30) among individuals with a sibling with nuclear cataract (nuclear grade > or = 3.0). The final fitted model indicated a magnitude of heritability for nuclear cataract of 35.6% (95% CI: 21.0%-50.3%) after adjustment for the covariates. CONCLUSIONS: Findings in this study are consistent with a genetic effect for age-related nuclear cataract, a common and clinically significant form of lens opacity.

Cortical, but not posterior subcapsular, cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors.

PURPOSE:

To quantify the risk for age-related cortical cataract and posterior subcapsular cataract (PSC) associated with having an affected sibling after adjusting for known environmental and personal risk factors.

DESIGN:

Sibling cohort study.

PARTICIPANTS:

Participants in the ongoing Salisbury Eye Evaluation (SEE) study (n = 321; mean age, 78.1+/-4.2 years) and their locally resident siblings (n = 453; mean age, 72.6+/-7.4 years) were recruited at the time of Rounds 3 and 4 of the SEE study. INTERVENTION/TESTING METHODS: Retroillumination photographs of the lens were graded for the presence of cortical cataract and PSC with the Wilmer grading system. The residual correlation between siblings' cataract grades was estimated after adjustment for a number of factors (age; gender; race; lifetime exposure to ultraviolet-B light; cigarette, alcohol, estrogen, and steroid use; serum antioxidants; history of diabetes; blood pressure; and body mass index) suspected to be associated with the presence of cataract.

RESULTS:

The average sibship size was 2.7 per family. Multivariate analysis revealed the magnitude of heritability (h(2)) for cortical cataract to be 24% (95% CI, 6%-42%), whereas that for PSC was not statistically significant (h(2) 4%; 95% CI, 0%-11%) after adjustment for the covariates. The model revealed that increasing age, female gender, a history of diabetes, and black race increased the odds of cortical cataract, whereas higher levels of provitamin A were protective. A history of diabetes and steroid use increased the odds for PSC.

CONCLUSIONS:

This study is consistent with a significant genetic effect for age-related cortical cataract but not PSC.

A fuzzified systematic adjustment of the robotic Darwinian PSO

The Darwinian Particle Swarm Optimization (DPSO) is an evolutionary algorithm that extends the Particle Swarm Optimization using natural selection to enhance the ability to escape from sub-optimal solutions. An extension of the DPSO to multi-robot applications has been recently proposed and denoted as Robotic Darwinian PSO (RDPSO), benefiting from the dynamical partitioning of the whole population of robots, hence decreasing the amount of required information exchange among robots. This paper further extends the previously proposed algorithm adapting the behavior of robots based on a set of context-based evaluation metrics. Those metrics are then used as inputs of a fuzzy system so as to systematically adjust the RDPSO parameters (i.e., outputs of the fuzzy system), thus improving its convergence rate, susceptibility to obstacles and communication constraints. The adapted RDPSO is evaluated in groups of physical robots, being further explored using larger populations of simulated mobile robots within a larger scenario.

Determining the Adjustment Baseline Parameters to Define an Accurate Customer Baseline Load

Demand response is an energy resource that has gained increasing importance in the context of competitive electricity markets and of smart grids. New business models and methods designed to integrate demand response in electricity markets and of smart grids have been published, reporting the need of additional work in this field. In order to adequately remunerate the participation of the consumers in demand response programs, improved consumers’ performance evaluation methods are needed. The methodology proposed in the present paper determines the characterization of the baseline approach that better fits the consumer historic consumption, in order to determine the expected consumption in absent of participation in a demand response event and then determine the actual consumption reduction. The defined baseline can then be used to better determine the remuneration of the consumer. The paper includes a case study with real data to illustrate the application of the proposed methodology.

Portuguese banks and the economic adjustment programme: balance sheet adjustments and impact on profitability

Double Degree. A Work Project presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics and a Masters Degree in Finance from Louvain School of Management

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment. Keywords: Equilibrium

On the labor share the long-run equilibrium and its adjustment process

This research computes an Equilibrium Labor Share using a VECM for a panel of 19 countries, analyzes what determines the speed at which the labor share adjusts towards that equilibrium and decomposes this adjustment in terms of real wages and employment. Results suggest that the speed at which a country adjusts decreases with employment protection legislation and labor taxes. Most countries’ labor shares adjustment is made through real wages changes instead of changing employment, suggesting that wage moderation policies may play an important role on the adjustment process without harming employment.

A qualitative approach to define the prototype of a Portuguese expatriate leader in Angola

This qualitative research analyzes the individual life experiences of Portuguese expatriate leaders who left their home country to work at organizations in Angola, a place that offers better job opportunities. Through interviews with those professionals and their followers, a prototype of a Portuguese expatriate leader in Angola has been developed. Even though Angola is a former Portuguese colony, it was at war for many years and so the economic situation and culture of the country are distant from what Portuguese workers are used too, which requires them to adapt and be open-minded to change.

Maternal coping, appraisals and adjustment following diagnosis of fetal anomaly.

OBJECTIVE: So far, associations between appraisals, maternal adjustment and coping following diagnosis of fetal anomaly have not been investigated in women who continue with their pregnancy. METHOD: This study measured maternal coping and adjustment after and appraisal of a diagnosis of fetal anomaly in 40 mothers who had continued with their pregnancy using a cross-sectional questionnaire design. RESULTS: Based on retrospective reporting, 35% of participants met full diagnostic criteria for post-traumatic stress disorder after having received the diagnosis. Women were significantly more depressed (p < 0.001) and anxious (p < 0.001) and reported significantly less positive affect (p < 0.05) after having received the diagnosis in comparison to the time after childbirth. There were no significant differences between emotion-focused and problem-focused coping. Stressful life events, women's age, number of people providing support and problem-focused coping explained 57.6% of variance in anxiety and depression after childbirth. Satisfaction with social support, emotion-focused coping and problem-focused coping significantly explained 40.6% of variance in positive affect after childbirth. CONCLUSION: Following a prenatal diagnosis and for the remainder of their pregnancy, particular attention should be paid to older mothers, those experiencing additional stressful life events and those who are socially isolated, as these women may experience greater distress after childbirth.