The Compact Muon Solenoid (CMS) is a general-purpose particle detector at the Large Hadron Collider (LHC) designed to study a wide range of particles produced in high energy collisions. The ...interaction of the beams with the pipe, shielding and detector supporting materials can produce neutrons, photons, electrons and positrons, forming a common background radiation field for CMS detector. A Monte-Carlo simulation is used to predict the background rate for a newly installed detector. In the forward region, the upgrade includes Gas Electron Multiplier (GEM) detectors called GE1/1. In this study, an estimate of the GE1/1 detector response to the background radiation is presented. The flux of background radiation is predicted using the FLUKA framework and the response of the detector is predicted using the GEANT4 framework. A comparison with actual GEM slice data is used as validation.
This paper deals with fault tolerant tracking controller (FTTC) design for vehicle dynamics system represented by an uncertain continuous time Takagi–Sugeno (T–S) model with unmeasurable premise ...variables. The goal is to ensure both state and fault estimations and the state trajectory reference tracking even if faults occur. To do this, a Proportional Integer Observer (PIO) with unknown inputs is then designed on the basis of the measure of the roll rate, the steering angle and the lateral offset given by the distance between the road centerline and the vehicle axe at a look-ahead distance. In this study, the faults affecting the system behavior are considered as time varying functions modeled by exponential functions or first order polynomials. Based on descriptor redundancy property solution are proposed in terms of Linear Matrix Inequalities (LMIs). Simulation results illustrate the applicability and the effectiveness of the proposed approaches on the vehicle system.
•We propose a fault tolerant tracking controller (FTTC) for vehicle dynamics system affected by time varying faults.•The system is represented by an uncertain continuous time Takagi–Sugeno (T–S) fuzzy model with unmeasurable premise variables.•A Proportional Integer Observer (PIO) with unknown inputs is designed to estimate both vehicle dynamics and road geometry.•Faults affecting the system behavior are considered as time varying functions.Conditions are proposed in terms of a Linear Matrix Inequality (LMI) by considering the descriptor redundancy approach.
Speeding Up and Parallelizing the GARFIELD Sheharyar, A.; Bouhali, O.; Castaneda, A.
EPJ Web of Conferences,
01/2018, Letnik:
174
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Garfield++ is a toolkit for the simulation of particle detectors that use gas and semi-conductors as sensitive medium. It takes enormous amount of time to complete the simulation of complex scenarios ...such as those involving high detector voltages, gases with large gains, or electric field meshes with large number of elements. We observed that most of the simulation time is being consumed in finding the correct element in the electric field mesh. We optimized the element search operation and achieved significant boost in the speed up. In addition, We added the parallel computing support in the toolkit to simulate multiple events simultaneously over multiple machines. In this paper, we present our approach of speeding up the computations and benchmark results.
The Accurate dosage prediction in Radiation Therapy is challenging, prompting a need for precision beyond conventional clinical Treatment Planning Systems (TPS). Monte Carlo-based methods are sought ...for their superior accuracy. The aim of this study is to compare dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, focusing on smaller fields. This study was initiated with a homogeneous validation of the TrueBeam STX system, using measurements obtained from the Centre Hospitalier Interregional Edith Cavell (CHIREC) in Brussels. The validation compared dosimetric functions (Percentage Depth Dose (PDD), Dose profile (DP) and Collimator scatter fraction (CSF)) employing the GAMMA index with a 2% / 2 mm criterion tolerance. Following this, heterogeneous studies examined dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, with a specific focus on smaller fields. Simulations were conducted using both platforms on chest phantoms with heterogeneous slabs representing bone, lung, and heart, each housing a central tumor. The impact of electronic equilibrium on tumors for different small field sizes was evaluated. Results showed a remarkable 99% agreement between measurements and GATE calculations in the homogeneous validation of the TrueBeam STX system. However, in heterogeneous studies, ACUROS consistently overestimated lung doses by up to 8% compared to GATE simulation, especially evident with a flattening filter and smaller beam sizes at density interfaces. This highlights significant dose estimation discrepancies between ACUROS and GATE, emphasizing the need for precise calculations. The findings support exploring Monte Carlo-based methods for enhanced accuracy in Radiation Therapy treatment planning.
In this paper, the direct modulation strategy of a three-level inverter with self stabilization of the dc link voltage is extended to a five-level inverter. Therefore, a new modeling and control ...strategy of a five-level three-phase diode-clamped inverter (DCI) is presented. The obtained modeling shows that modulated multilevel voltages are obtained by combination of eight different three-level functions, which are called modulation functions. Therefore, a space-vector scheme without using a Park transform is explained. Based on this algorithm, the location of the reference voltage vector can be easily determined. Then, the voltage vectors are selected to generate corresponding levels and simultaneously their durations are calculated. More over, the redundancies of different switch configurations for the generation of intermediate voltages are used to limit the deviation of capacitor voltages. Experimental results are given to illustrate the proposed control strategy of the three-phase three-level diode clamped inverter. Then, obtained results for a five-level three-phase DCI with the extended version of the control strategy are presented to show the good performances of the proposed balancing modulation.
•FLUKA PET tools: a dedicated FLUKA package for PET simulations.•Simulation of hadrontherapy irradiation scenarios, with in-beam PET, is now possible.•The higher imaging potential of 11C and 15O in ...in-beam PET is assessed.•The tools feature a newly developed embedded MLEM code for image reconstruction.
The new developments of the FLUKA Positron-Emission-Tomography (PET) tools are detailed. FLUKA is a fully integrated Monte Carlo (MC) particle transport code, used for an extended range of applications, including Medical Physics. Recently, it provided the medical community with dedicated simulation tools for clinical applications, including the PET simulation package. PET is a well-established imaging technique in nuclear medicine, and a promising method for clinical in vivo treatment verification in hadrontherapy. The application of clinically established PET scanners to new irradiation environments such as hadrontherapy requires further experimental and theoretical research to which MC simulations could be applied. The FLUKA PET tools, besides featuring PET scanner models in its library, allow the configuration of new PET prototypes via the FLUKA Graphical User Interface (GUI) Flair. Both the beam time structure and scan time can be specified by the user, reproducing PET acquisitions in time, in a particle therapy scenario. Furthermore, different scoring routines allow the analysis of single and coincident events, and identification of parent isotopes generating annihilation events. Two reconstruction codes are currently supported: the Filtered Back–Projection (FBP) and Maximum–Likelihood Expectation Maximization (MLEM), the latter embedded in the tools. Compatibility with other reconstruction frameworks is also possible. The FLUKA PET tools package has been successfully tested for different detectors and scenarios, including conventional functional PET applications and in beam PET, either using radioactive sources, or simulating hadron beam irradiations. The results obtained so far confirm the FLUKA PET tools suitability to perform PET simulations in R&D environment.
The development and optimization of Micro Pattern Gaseous Detectors relies heavily on the simulation of the geometry, the avalanche process and the signal generation inside the detector. In complex ...scenarios where high detector gas gains are required, the simulation can be computationally expensive and can become a bottleneck for the R&D process. In this paper we present two approaches to reduce the simulation execution time when using the Garfield++ simulation package. We present the two approaches and discuss the results.
Introduction La chirurgie bariatrique non seulement induit une perte drastique et durable de poids, mais permet aussi une rémission durable du DT2 chez les malades obèses morbides. La rémission du ...diabète se produit souvent dans les quelques jours qui suivent la chirurgie, bien avant toute perte significative de poids. Les mécanismes physiologiques et biochimiques qui expliquent l’impact de la chirurgie bariatrique sur l’homéostasie du glucose sont cependant mal connus. Notre objectif est d’utiliser la modélisation mathématique pour essayer de mieux comprendre les mécanismes derrière la rémission du DT2 après chirurgie bariatrique. Matériels et méthodes Une méthode mathématique générale a été proposée pour estimer la réponse biochimique aux médicaments, aux chirurgies, ou les autres interventions médicales. Cette méthode a été ensuite appliquée a un modèle très simple de la réponse à la dérivation gastrique Roux-en-Y (Roux-en-Y gastric bypass). Résultats Il y a manifestement des effets multiples et très complexes de la chirurgie bariatrique. Les résultats de notre modèle confirment que la rémission de diabète après la chirurgie bariatrique peut être expliquée en partie par une augmentation de la sécrétion postprandiale de GLP-1, et ses effets sur la sécrétion d’insuline. Cependant notre modèle suggère aussi que d’autres mécanismes sont susceptibles d’être impliqués, y compris éventuellement par un mécanisme de transport de glucose dans les cellules des organes périphériques indépendamment de l’effet de l’insuline. Cette hypothèse est supportée par l’induction d’une diminution de la glycémie dans des souris souffrant de DT1 lorsqu’elles expriment une molécule isolée des cellules intestinales et dont la production est augmentée après la chirurgie bariatrique chez le rat. Conclusion Il est possible qu’une partie de l’effet de la chirurgie bariatrique sur le DT2 soit due a un facteur qui induit le transport du glucose dans les cellules independamment de l’insulin.
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