Improving the performance of independent task assignment heuristics minmin, maxmin and mufferage

Cataloged from PDF version of article.MinMin, MaxMin, and Sufferage are constructive heuristics that are widely and successfully used in assigning independent tasks to processors in heterogeneous computing systems. All three heuristics are known to run in O(KN2) time in assigning N tasks to K processors. In this paper, we propose an algorithmic improvement that asymptotically decreases the running time complexity of MinMin to O(KN log N) without affecting its solution quality. Furthermore, we combine the newly proposed MinMin algorithm with MaxMin as well as Sufferage, obtaining two hybrid algorithms. The motivation behind the former hybrid algorithm is to address the drawback of MaxMin in solving problem instances with highly skewed cost distributions while also improving the running time performance of MaxMin. The latter hybrid algorithm improves the running time performance of Sufferage without degrading its solution quality. The proposed algorithms are easy to implement and we illustrate them through detailed pseudocodes. The experimental results over a large number of real-life data sets show that the proposed fast MinMin algorithm and the proposed hybrid algorithms perform significantly better than their traditional counterparts as well as more recent state-of-the-art assignment heuristics. For the large data sets used in the experiments, MinMin, MaxMin, and Sufferage, as well as recent state-of-the-art heuristics, require days, weeks, or even months to produce a solution, whereas all of the proposed algorithms produce solutions within only two or three minutes

Hamiltonian formalism and the Garrett-Munk spectrum of internal waves in the ocean

Wave turbulence formalism for long internal waves in a stratified fluid is developed, based on a natural Hamiltonian description. A kinetic equation appropriate for the description of spectral energy transfer is derived, and its self-similar stationary solution corresponding to a direct cascade of energy toward the short scales is found. This solution is very close to the high wavenumber limit of the Garrett-Munk spectrum of long internal waves in the ocean. In fact, a small modification of the Garrett-Munk formalism includes a spectrum consistent with the one predicted by wave turbulence.Comment: 4 pages latex fil

Mathematical Modelling of Endocrine Systems

This is the final (in press) version. Available from Elsevier via the DOI in this recordHormone rhythms are ubiquitous and essential to sustain normal physiological functions. Combined mathematical modelling and experimental approaches have shown that these rhythms result from regulatory processes occurring at multiple levels of organisation and require continuous dynamic equilibration, particularly in response to stimuli. We review how such an interdisciplinary approach has been successfully applied to unravel complex regulatory mechanisms in the metabolic, stress, and reproductive axes. We discuss how this strategy is likely to be instrumental for making progress in emerging areas such as chronobiology and network physiology. Ultimately, we envisage that the insight provided by mathematical models could lead to novel experimental tools able to continuously adapt parameters to gradual physiological changes and the design of clinical interventions to restore normal endocrine function.Medical Research Council (MRC)Engineering and Physical Sciences Research Council (EPSRC)Wellcome Trus

Energy spectra of the ocean's internal wave field: theory and observations

The high-frequency limit of the Garrett and Munk spectrum of internal waves in the ocean and the observed deviations from it are shown to form a pattern consistent with the predictions of wave turbulence theory. In particular, the high frequency limit of the Garrett and Munk spectrum constitutes an {\it exact} steady state solution of the corresponding kinetic equation.Comment: 4 pages, one color figur

Needs, expectations and consequences for the child growing up in a family with a parent with mental illness

Parental mental illness is considered one of the strongest risk-factors for development of offspring psychopathology. The lack of pan-European guidelines for empowering children of parents with mental illness led to EU project CAMILLE - Empowerment of Children and Adolescents of Mentally Ill Parents through Training of Professionals working with children and adolescents. The first task in this project, was to analyse needs, expectations and consequences for children, with respect to living with a parent with mental illness. The aim this paper is to report results of these analyses. The qualitative research was conducted in England, Finland, Germany, Italy, Norway, Poland and Scotland (N=96). There were 3 types of focus groups: (1) professionals (doctors, nurses, psychologists, social workers), (2) adult children and partners of a person with mental illness, (3) parents who have experienced mental illness during their parenthood. Framework analysis method was used. Results of the study highlighted that the main consequences for children of parental mental illness were role reversal, emotional and behavioural problems, lack of parent’s attention and stigma. The main needs of these children were emotional support, security and multidisciplinary help. Implications for practice are: (1) professionals working with parents with mental illness should be aware of the specific consequences for the children; (2) to empower children they should focus on them, but not excluding parents from the parental roles; (3) the multi-agency collaboration is necessary; (4) schools should provide counselling and teach staff and students about mental health problems to reduce stigm

Moving to an A1C-Based Diagnosis of Diabetes Has a Different Impact on Prevalence in Different Ethnic Groups

Objective: To compare screen detected diabetes prevalence and the degree of diagnostic agreement by ethnicity with the current OGTT-based and newly proposed HbA<SUB>1c</SUB>-based diagnostic criteria. Research design and methods: Six studies (1999-2009) from Denmark, United Kingdom, Australia, Greenland, Kenya, and India were tested for the probability of an HbA<SUB>1c</SUB> ≥ 6.5% among diabetes cases based on an OGTT. The difference in probability between centers was analyzed by logistic regression adjusting for relevant confounders. Results: Diabetes prevalence was lower with the HbA<SUB>1c</SUB>-based diagnostic criteria in four out of six studies. The probability of an HbA<SUB>1c</SUB> ≥ 6.5% among OGTT-diagnosed cases ranged widely (17.0 to 78.0%) by study center. Differences in diagnostic agreement between ethnic sub-groups in the United Kingdom study were of the same magnitude as between-country comparisons. Conclusions: A shift to an HbA<SUB>1c</SUB>-based diagnosis for diabetes will have substantially different consequences for diabetes prevalence across ethnic groups and populations

Elevated Levels of the Anti-Inflammatory Interleukin-1 Receptor Antagonist Precede the Onset of Type 2 Diabetes: The Whitehall II Study

OBJECTIVE—Interleukin-1 receptor antagonist (IL-1Ra), a natural inhibitor of interleukin-1β, has been shown to improve β-cell function and glycemic control in patients with type 2 diabetes. The aim of this study was to investigate whether baseline systemic levels of IL-1Ra are associated with incident type 2 diabetes during more than 10 years of follow-up

Zettawatt-Exawatt Lasers and Their Applications in Ultrastrong-Field Physics: High Energy Front

Since its birth, the laser has been extraordinarily effective in the study and applications of laser-matter interaction at the atomic and molecular level and in the nonlinear optics of the bound electron. In its early life, the laser was associated with the physics of electron volts and of the chemical bond. Over the past fifteen years, however, we have seen a surge in our ability to produce high intensities, five to six orders of magnitude higher than was possible before. At these intensities, particles, electrons and protons, acquire kinetic energy in the mega-electron-volt range through interaction with intense laser fields. This opens a new age for the laser, the age of nonlinear relativistic optics coupling even with nuclear physics. We suggest a path to reach an extremely high-intensity level $10^{26-28}$W/cm$^2$ in the coming decade, much beyond the current and near future intensity regime $10^{23}$W/cm$^2$, taking advantage of the megajoule laser facilities. Such a laser at extreme high intensity could accelerate particles to frontiers of high energy, tera-electron-volt and peta-electron-volt, and would become a tool of fundamental physics encompassing particle physics, gravitational physics, nonlinear field theory, ultrahigh-pressure physics, astrophysics, and cosmology. We focus our attention on high-energy applications in particular and the possibility of merged reinforcement of high-energy physics and ultraintense laser.Comment: 25 pages. 1 figur

Electromagnetic energy penetration in the self-induced transparency regime of relativistic laser-plasma interactions

Two scenarios for the penetration of relativistically intense laser radiation into an overdense plasma, accessible by self-induced transparency, are presented. For supercritical densities less than 1.5 times the critical one, penetration of laser energy occurs by soliton-like structures moving into the plasma. At higher background densities laser light penetrates over a finite length only, that increases with the incident intensity. In this regime plasma-field structures represent alternating electron layers separated by about half a wavelength by depleted regions.Comment: 9 pages, 4 figures, submitted for publication to PR

Mendelian randomization study of B-type natriuretic peptide and type 2 diabetes: evidence of causal association from population studies

&lt;p&gt;Background: Genetic and epidemiological evidence suggests an inverse association between B-type natriuretic peptide (BNP) levels in blood and risk of type 2 diabetes (T2D), but the prospective association of BNP with T2D is uncertain, and it is unclear whether the association is confounded.&lt;/p&gt; &lt;p&gt;Methods and Findings: We analysed the association between levels of the N-terminal fragment of pro-BNP (NT-pro-BNP) in blood and risk of incident T2D in a prospective case-cohort study and genotyped the variant rs198389 within the BNP locus in three T2D case-control studies. We combined our results with existing data in a meta-analysis of 11 case-control studies. Using a Mendelian randomization approach, we compared the observed association between rs198389 and T2D to that expected from the NT-pro-BNP level to T2D association and the NT-pro-BNP difference per C allele of rs198389. In participants of our case-cohort study who were free of T2D and cardiovascular disease at baseline, we observed a 21% (95% CI 3%-36%) decreased risk of incident T2D per one standard deviation (SD) higher log-transformed NT-pro-BNP levels in analysis adjusted for age, sex, body mass index, systolic blood pressure, smoking, family history of T2D, history of hypertension, and levels of triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. The association between rs198389 and T2D observed in case-control studies (odds ratio = 0.94 per C allele, 95% CI 0.91-0.97) was similar to that expected (0.96, 0.93-0.98) based on the pooled estimate for the log-NT-pro-BNP level to T2D association derived from a meta-analysis of our study and published data (hazard ratio = 0.82 per SD, 0.74-0.90) and the difference in NT-pro-BNP levels (0.22 SD, 0.15-0.29) per C allele of rs198389. No significant associations were observed between the rs198389 genotype and potential confounders.&lt;/p&gt; &lt;p&gt;Conclusions: Our results provide evidence for a potential causal role of the BNP system in the aetiology of T2D. Further studies are needed to investigate the mechanisms underlying this association and possibilities for preventive interventions.&lt;/p&gt