Local Analysis of Human Cortex in MRI Brain Volume

This paper describes a method for subcortical identification and labeling of 3D medical MRI images. Indeed, the ability to identify similarities between the most characteristic subcortical structures such as sulci and gyri is helpful for human brain mapping studies in general and medical diagnosis in particular. However, these structures vary greatly from one individual to another because they have different geometric properties. For this purpose, we have developed an efficient tool that allows a user to start with brain imaging, to segment the border gray/white matter, to simplify the obtained cortex surface, and to describe this shape locally in order to identify homogeneous features. In this paper, a segmentation procedure using geometric curvature properties that provide an efficient discrimination for local shape is implemented on the brain cortical surface. Experimental results demonstrate the effectiveness and the validity of our approach

Microseismic activity and fluid fault interactions: some results from the Corinth Rift Laboratory (CRL), Greece

International audienceThe Gulf of Corinth, in western-central Greece, is one of the fastest continental rifts in theworld. In its western section near the city of Aigion, the previous work has outlined theexistence of a shallow dipping seismogenic zone between 5 and 12 km. This seismic activityhas been monitored with a network of 12 three-component stations for the period 2000–2007. Three, few months long, seismic swarms have been observed. They mobilize a complexstructural fault system that associates both shallow dipping elements and subvertical structureswith very different azimuths, some of which extend to depths greater than that of the shallowdipping zone. The swarm activity associates intensely active, short crises (a few days) withmore quiescent periods. The long-term growth velocity of the seismically activated domainsis compatible with a fluid diffusion process. Its characteristics are discussed in the context ofthe results from the 1000 m deep AIG10 well that intersects the Aigion Fault at 760 m. Thevertical growth directions of the seismically activated volumes outline two different sources forthe fluid and imply non-steady pressure conditions within the seismic domain. The diffusivityalong the cataclastic zone of the faults is in the order of 1 m2s−1, while faults act as hydraulicbarrier in the direction perpendicular to their strike. If the vertical direction is a principalstress component, the high pore pressure values that must be reached to induce slip on theshallowly dipping planes can result only from transitory dynamic conditions. It is argued thatthe shallow dipping active seismic zone is only local and does not correspond to a 100 kmscale decollement zone. We propose to associate the localization process with deep fluid fluxesthat have progressively modified the local stress field and may be the cause for the quiescenceof the West Heliki Fault presently observed

Boiling process assessment for absorption heat pumps: A review

Absorption technology becomes an attractive option for cooling or heating when driven by solar thermal energy, residual heat from different processes, or geothermal energy. Further development of this technology could help to cover current cooling or heating requirements and have a much lower impact on the environment than mechanical compression cooling and heat pumps systems. Moreover, the rising cost of electrical energy added to the issue of climate change are reasons to move towards the development of environmental and sustainable energy technologies. The desorbers are key components of absorption heat pump technologies. Studies in the open literature on desorbers show advances in new design concepts to enhance heat and mass transfer with different working fluids. Therefore, the objective of this review is to identify, summarise, and discuss the experimental studies that deal with the boiling process in desorbers and boiling correlations specifically for use in absorption heat pump technologies. It includes a comprehensive scrutiny on the boiling phenomenon in pool desorbers, falling-film desorbers, and forced flow desorbers for conventional and promising working fluids, and details the experimental techniques and the latest advances in desorber design concepts. Finally, the review contains proposals for future studies to be carried out so as to contribute to the further development of absorption heat pump technologies

EBP: An Efficient Broadcast Protocol for Warning Message Dissemination in VANETs

Vehicular Ad-hoc Networks (VANETs) enable vehicle-to-vehicle communications to share relevant road information with various applications. Road safety is one of the main objectives of VANETs that has attracted great interest from researchers. Other so-called comfort applications have also been studied which can improve driving experience and passenger safety. In all these applications, sharing of warning messages can help drivers minimize accidents and congestions, and plan better itinerary during the congestion situations or the anticipation of potential and highly hazardous events. In this paper, we present an efficient broadcast protocol (EBP) for broadcasting warning messages in VANETs. As an improved strategy for alert data dissemination, EBP can be applied in whatever the nature of the risk, with a particular focus on mobile dangers. We first conduct an in-depth analysis and evaluation, under different conditions, of the existing approaches and mechanisms used for information dissemination in VANETs. Then, we point out their drawbacks and design the EBP to avoid these drawbacks. As a result, the EBP is an improved, well-justified and more effective protocol. We validate it by simulation experiments under various scenarios

Energy efficiency of a 3-level shunt active power filter powered by a fuel-cell / battery DC bus with regulated duty cycles

Introduction. Nowadays, electrical energy is indispensable in industrial, tertiary and domestic appliances. However, its efficiency is becoming affected by the presence of the disturbances that appear in the electrical networks such as harmonics, unbalance, sags/swells, flickers …etc. Indeed, the disturbances cause a decrease in the power factor and an increase in the power losses. In this paper, the harmonic disturbance is considered and a 3-level shunt active power filter powered by a hybrid fuel-cell/battery DC is applied to mitigate current harmonic components from the electrical feeder. Aim. Studying the energy efficiency of a system based on a 3-level shunt active filter powered by a hybrid fuel-cell / battery DC bus. Methodology. It is a matter of finding the suitable formulas that express the efficiency and the relative power losses according to the load factor (which is the ratio between the short-circuit active power and the load active power) and the load power factor. The DC bus energy is controlled using an energy management algorithm that contributes in generating the required reference input currents and output voltages of the fuel-cell and the battery. The DC/DC converters control circuits are performed in a closed loop by means of regulated duty cycles. Results. The simulation results carried-out under MATLAB/Simulink environment show better filtering quality if compared with the case of open loop control of the DC/DC converters and lesser differences between the fuel-cell power, the battery power and their respective reference powers. Which concerns the energy efficiency, the results demonstrate that higher efficiency and lower relative power losses can be achieved only when higher load factor and load power factor are attained. Therefore, the compensating system of the power factor is very important to improve the energy efficiency.Вступ. У наш час електрична енергія є незамінною для промислових, проміжних і побутових приладів. Однак на її ефективність впливає наявність порушень, що виникають в електричних мережах, таких як гармоніки, дисбаланс, провисання/розбухання, мерехтіння тощо. Дійсно, порушення викликають зменшення коефіцієнта потужності та збільшення втрат потужності. У цій роботі розглянуто гармонічні порушення та застосовано 3-рівневий шунтуючий фільтр активної потужності з живленням від гібридного паливного елемента/акумулятора постійного струму для пом'якшення струмових гармонічних компонентів з електропостачанням від електричного фідера. Мета. Дослідження енергоефективності системи на основі 3-рівневого шунтуючого активного фільтра з живленням від гібридної шини постійного струму з паливним елементом/акумулятором. Методика. Потрібно знайти  відповідні формули, які виражають ефективність та відносні втрати потужності у відповідності до коефіцієнта навантаження (це відношення активної потужності короткого замикання та активної потужності навантаження) та коефіцієнта потужності навантаження. Енергія шини постійного струму контролюється за допомогою алгоритму управління енергією, який сприяє формуванню необхідних опорних вхідних струмів та вихідних напруг паливного елемента й акумулятора. Схеми управління DC/DC перетворювачами виконуються у замкненому контурі за допомогою регульованих робочих циклів. Результати. Результати моделювання, проведеного у середовищі MATLAB/Simulink, показують кращу якість фільтрації у порівнянні з випадком управління з відкритим контуром DC/DC перетворювачів  та менші відмінності між потужністю паливних елементів, потужністю акумулятора та їх відповідною порівняльною потужністю. Що стосується енергоефективності, результати показують, що більший ККД та менші відносні втрати потужності можна досягти лише тоді, коли досягаються більший коефіцієнт навантаження та коефіцієнт потужності навантаження. Тому компенсуюча система коефіцієнта потужності дуже важлива для підвищення енергоефективності

AN INNOVATIVE ALGORITHM FOR A HYBRID FC/BATTERY SYSTEM ENERGY MANAGEMENT

Purpose. This paper targets to manage the energy of a hybrid fuel-cell (FC)/battery power system using an innovative algorithm. The hybrid FC/Battery power system is based on four stacks PEM FCs and a NiMH battery, boost and buck DC choppers for controlling the FC and the battery input currents respectively and a developed algorithm both for managing the power system energies and for delivering the FC and the battery reference output voltages compulsory for the DC/DC converters control circuits. The study is verified by means of computer simulations using MATLAB/Simulink where several cases of the battery SOC and the power demand levels were taken into account. The results demonstrate a good functioning of the proposed hybrid FC/Battery power system managing algorithm.Мета. Стаття спрямована на управління енергією гібридної системи живлення від паливного елемента/акумулятора за допомогою інноваційного алгоритму. Гібридна система живлення паливний елемент/акумулятор заснована на чотирьох батареях паливних елементів з протонообмінними мембранами та NiMH акумуляторі, підсилювачах і послаблювачах постійного струму для управління паливним елементом та вхідними струмами батареї відповідно та розробленому алгоритмі як для управління енергією енергосистеми, так і для подачі на паливний елемент і акумулятор вихідної напруги, обов'язкової для схем управління перетворювачами постійного струму. Дослідження перевірено за допомогою комп’ютерного моделювання з використанням MATLAB/Simulink, де було враховано кілька випадків рівня заряду акумулятора та рівнів споживання енергії. Результати демонструють добре функціонування запропонованого гібридного алгоритму управління системою живлення від паливного елемента/акумулятора

The Neuro-genetic approach for estimating the compression index

In the last decade, a number of empirical correlations have been proposed to connect the compression index to other soil parameters, such as liquid limit, plasticity index and the void index. This paper presents a correlation study between the physical properties and compression index which was conducted on normally consolidated clay by the hybridization of two approaches (artificial neuronal networks and genetic algorithms). A comparison was made between the measured experimentally and predictions compression indexes. The obtained results indicate that the Neuro-genetic model has the ability to accurately predict the compression index thus be used in practice by geotechnicians

Checking and Enforcing Security through Opacity in Healthcare Applications

The Internet of Things (IoT) is a paradigm that can tremendously revolutionize health care thus benefiting both hospitals, doctors and patients. In this context, protecting the IoT in health care against interference, including service attacks and malwares, is challenging. Opacity is a confidentiality property capturing a system's ability to keep a subset of its behavior hidden from passive observers. In this work, we seek to introduce an IoT-based heart attack detection system, that could be life-saving for patients without risking their need for privacy through the verification and enforcement of opacity. Our main contributions are the use of a tool to verify opacity in three of its forms, so as to detect privacy leaks in our system. Furthermore, we develop an efficient, Symbolic Observation Graph (SOG)-based algorithm for enforcing opacity