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Search Results: 1 - 10 of 403 matches for " Kyriakos Georgiou "
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On the Value and Limits of Multi-level Energy Consumption Static Analysis for Deeply Embedded Single and Multi-threaded Programs
Kyriakos Georgiou,Steve Kerrison,Kerstin Eder
Computer Science , 2015,
Abstract: There is growing interest in lowering the energy consumption of computation. Energy transparency is a concept that makes a program's energy consumption visible from software to hardware through the different system layers. Such transparency can enable energy optimizations at each layer and between layers, and help both programmers and operating systems make energy aware decisions. The common methodology of extracting the energy consumption of a program is through direct measurement of the target hardware. This usually involves specialized equipment and knowledge most programmers do not have. In this paper, we examine how existing methods for static resource analysis and energy modeling can be utilized to perform Energy Consumption Static Analysis (ECSA) for deeply embedded programs. To investigate this, we have developed ECSA techniques that work at the instruction set level and at a higher level, the LLVM IR, through a novel mapping technique. We apply our ECSA to a comprehensive set of mainly industrial benchmarks, including single-threaded and also multi-threaded embedded programs from two commonly used concurrency patterns, task farms and pipelines. We compare our ECSA results to hardware measurements and predictions obtained based on simulation traces. We discuss a number of application scenarios for which ECSA results can provide energy transparency and conclude with a set of new research questions for future work.
Static analysis of energy consumption for LLVM IR programs
Neville Grech,Kyriakos Georgiou,James Pallister,Steve Kerrison,Jeremy Morse,Kerstin Eder
Computer Science , 2014, DOI: 10.1145/2764967.2764974
Abstract: Energy models can be constructed by characterizing the energy consumed by executing each instruction in a processor's instruction set. This can be used to determine how much energy is required to execute a sequence of assembly instructions, without the need to instrument or measure hardware. However, statically analyzing low-level program structures is hard, and the gap between the high-level program structure and the low-level energy models needs to be bridged. We have developed techniques for performing a static analysis on the intermediate compiler representations of a program. Specifically, we target LLVM IR, a representation used by modern compilers, including Clang. Using these techniques we can automatically infer an estimate of the energy consumed when running a function under different platforms, using different compilers. One of the challenges in doing so is that of determining an energy cost of executing LLVM IR program segments, for which we have developed two different approaches. When this information is used in conjunction with our analysis, we are able to infer energy formulae that characterize the energy consumption for a particular program. This approach can be applied to any languages targeting the LLVM toolchain, including C and XC or architectures such as ARM Cortex-M or XMOS xCORE, with a focus towards embedded platforms. Our techniques are validated on these platforms by comparing the static analysis results to the physical measurements taken from the hardware. Static energy consumption estimation enables energy-aware software development, without requiring hardware knowledge.
A Global Solution of the Einstein-Maxwell Field Equations for Rotating Charged Matter  [PDF]
Andreas Georgiou
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.329168
Abstract: A stationary axially symmetric exterior electrovacuum solution of the Einstein-Maxwell field equations was obtained. An interior solution for rotating charged dust with vanishing Lorentz force was also obtained. The two spacetimes are separated by a boundary which is a surface layer with surface stress-energy tensor and surface electric 4-current. The layer is the spherical surface bounding the charged matter. It was further shown, that all the exterior physical quantities vanished at the asymptotic spatial infinity where spacetime was shown to be flat. There are two different sets of junction conditions: the electromagnetic junction conditions, which were expressed in the traditional 3-dimensional form of classical electromagnetic theory; and the considerably more complicated gravitational junction conditions. It was shown that both—the electromagnetic and gravitational junction conditions—were satisfied. The mass, charge and angular momentum were determined from the metric. Exact analytical formulae for the dipole moment and gyromagnetic ratio were also derived. The conditions, under which the latter formulae gave Blackett’s empirical result for rotating stars, were investigated.
The Angular Momenta Dipole Moments and Gyromagnetic Ratios of the Electron and the Proton  [PDF]
A. Georgiou
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.514125
Abstract:

We had previously obtained analytical formulae for the dipole moments and angular momenta of rotating spherical bodies. The resulting formulae were applied to the Sun, the star 78 Virginis and the Earth. The agreement of the theoretical formulae with the actual real situations is indeed remarkable. In this note we apply the same formulae to the electron and the proton, using the classical values of the radii, so no quantum mechanical treatment is considered.

The Angular Momenta, Dipole Moments and Gyromagnetic Ratios of the Neutron and the Muon  [PDF]
Andreas Georgiou
Journal of Modern Physics (JMP) , 2015, DOI: 10.4236/jmp.2015.67104
Abstract: The dipole moments, angular momenta and gyromagnetic ratios of the electron and the proton were obtained earlier. In this note, we derive the corresponding expressions for the neutron and the muon. This work relies on the results obtained earlier for the angular momenta and dipole moments of rotating spherical bodies.
Inferring Parametric Energy Consumption Functions at Different Software Levels: ISA vs. LLVM IR
Umer Liqat,Kyriakos Georgiou,Steve Kerrison,Pedro Lopez-Garcia,John P. Gallagher,Manuel V. Hermenegildo,Kerstin Eder
Computer Science , 2015,
Abstract: The static estimation of the energy consumed by program executions is an important challenge, which has applications in program optimization and verification, and is instrumental in energy-aware software development. Our objective is to estimate such energy consumption in the form of functions on the input data sizes of programs. We have developed a tool for experimentation with static analysis which infers such energy functions at two levels, the instruction set architecture (ISA) and the intermediate code (LLVM IR) levels, and reflects it upwards to the higher source code level. This required the development of a translation from LLVM IR to an intermediate representation and its integration with existing components, a translation from ISA to the same representation, a resource analyzer, an ISA-level energy model, and a mapping from this model to LLVM IR. The approach has been applied to programs written in the XC language running on XCore architectures, but is general enough to be applied to other languages. Experimental results show that our LLVM IR level analysis is reasonably accurate (less than 6.4% average error vs. hardware measurements) and more powerful than analysis at the ISA level. This paper provides insights into the trade-off of precision versus analyzability at these levels.
The Development of the Greek Personality Assessment Inventory  [PDF]
Dimitrios Georgiou Lyrakos
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.28122
Abstract: Presented in the current report are the reliability analysis of the Greek Personality Assessment Inventory (PAI), the differences between the means and the standard deviation (SD) of the Greek and the US sample and the creation of the maximum non-clinical T Scores for each of the scale and subscale produced by the Greek standardization sample. The PAI is considered, in the US and in many European countries, one of the most reliable multidimensional psychometric inventories. The PAI consists of 344 questions that are separated in non-over- lapping scales of clinical, treatment focus, personality and validity context. The present, mixed design study had 1870 participants, males and females between the ages of 20 and 55.The participants were 1120 non-clinical (standardization sample), 450 psychiatric inpatients and 300 psychiatric outpatients, who were gathered from 4 major regions of Greece.
Severe Thyrotoxicosis Does Not Accelerate 1a-Hydroxylation of 25-Hydroxyvitamin D3 in Dogs. Experimental Study  [PDF]
Christos Georgiou Velentzas
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.412093
Abstract:

Two healthy dogs weighing 18 kg and 13 kg each received an intravenous injection of 7 μg/kg 25-hydroxyvitamin D3 (25OHD3). Subsequently, they were blood-sampled in order to determine the plasma levels of 25(OH)D3 over 4-hourly time intervals and for a time period of 24 hours. After a period of 18 days since the last blood sampling, the animals were brought to a hyperthyroid state and the intravenous injection of 7 μg/kg 25OHD3 was repeated. Blood sampling was performed every 4 hours and over a time period of 24 hours in order to determine the levels of 25OHD3. The graphic plotting of plasma levels of 25OHD3 in the euthyroid state did not differ from that in the hyperthyroid state. This finding in dog animal experimentation is indicative that the increased levels of thyroid hormones did not affect the activity of CYP27B1 and CYP24A1 enzymes that are related to the catabolism of 25OHD3 over a minimum of 24 hours period.

Mathematical thought before the fall of an empire: the Cardinal Bessarion's vita sum numa et arte plato
Kyriakos Petakos
Matemáticas : Ense?anza Universitaria , 2009,
Abstract: An empire is just about to collapse for ever bringing about an intellectual sort of death that is detrimental not only to the nation that suffers the loss of his heart, the Greeks, but also the whole western civilization. In these last tragical moments where survival monopolizes the human existence as a form of self-preservation, mathematical thinking prevails on the mind of a clergy personality. It is the cardinal Bessarion, whose manuscripts scattered in the aristocraticsometime ago full of Greeks -suburbs of Bosporus reveal parallel to his love for such a wellstructured science another application of mathematics rarely conceived by today educators: oratory and its undoubted power.
Important mathematical concepts at the dawn of science in Byzantium: the philosopher C. M. Psellos
Kyriakos Petakos
Matemáticas : Ense?anza Universitaria , 2010,
Abstract: The Byzantine Empire, an empire that lasted over one thousand years, is acknowledged nowadays as the spiritual source of the European intellectual rebirth of the middle ages. What really distinguishes this great state from any other important country of the time is among others a solid conviction of equality of chances in at least a fundamental component of progress:education. What we try to demonstrate here is the fact that natural sciences such as mathematics were treated in the above sense with the utmost respect by remarkable personalities whose traditional role seemed to be far from the common sense of this scienti c branch, but in its true nature was nourished and fostered by the essence of mathematics. Diplomacy and highly exerted church leadership intertwined with mathematical exploration.
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