Decentralized Sensor Fault-Tolerant Control of DC Microgrids Using the Attracting Ellipsoid Method

System stability deterioration in microgrids commonly occurs due to unpredictable faults and equipment malfunctions. Recently, robust control techniques have been used in microgrid systems to address these difficulties. In this paper, for DC-islanded microgrids that have sensors faults, a new passive fault-tolerant control strategy is developed. The suggested approach can be used to maintain system stability in the presence of flaws, such as faulty actuators and sensors, as well as component failures. The suggested control is effective when the fault is never recognized (or when the fault is not being precisely known, and some ambiguity in the fault may be interpreted as uncertainty in the system's dynamics following the fault). The design is built around a derived sufficient condition in the context of linear matrix inequalities (LMIs) and the attractive ellipsoid technique. The ellipsoidal stabilization idea is to bring the state trajectories into a small region including the origin (an ellipsoid with minimum volume) and the trajectories will not leave the ellipsoid for the future time. Finally, computational studies on a DC microgrid system are carried out to assess the effectiveness of the proposed fault-tolerant control approach. When compared with previous studies, the simulation results demonstrate that the proposed control technique can significantly enhance the reliability and efficiency of DC microgrid systems.

Wireless implantable and biodegradable sensors for postsurgery monitoring: current status and future perspectives

In in vivo postsurgery monitoring, the use of wireless biodegradable implantable sensors has gained and is gaining a lot of interest, particularly in cases of monitoring for a short period of time. The employment of biodegradable materials allows the circumvention of secondary surgery for device removal. Additionally, the use of wireless communication for data elaboration avoids the need for transcutaneous wires. As such, it is possible to prevent possible inflammation and infections associated with long-term implants which are not wireless. It is expected that microfabricated biodegradable sensors will have a strong impact in acute or transient biomedical applications. However, the design of such high-performing electronic systems, both fully biodegradable and wireless, is very complex, particularly at small scales. The associated technologies are still in their infancy and should be more deeply and extensively investigated in animal models and, successively, in humans, before being clinically implemented. In this context, the present review aims to provide a complete overview of wireless biodegradable implantable sensors, covering the vital signs to be monitored, the wireless technologies involved, and the biodegradable materials used for the production of the devices, as well as designed devices and their applications. In particular, both their advantages and drawbacks are highlighted, and the key challenges faced, mainly associated with fabrication techniques, and control over degradation kinetics and biocompatibility of the device, are reported and discussed.

Experimental evaluation of an ultrasound technique for the biometric recognition of human hand anatomic elements

In this work the moving ultrasound linear array technique has been used to perform 3D echographic images of different human hands, in order to evaluate this technique to biometric recognition purposes. An automated set up, based on a commercial echographic machine provided with a high frequency (12 MHz) linear array, has been built up. The probe is moved in the direction orthogonal to the array and at each step a B-scan is performed and stored to form a 3D matrix representing the under skin hand volume. B-scan and C-scan images of the hand of different users were analysed and compared. The results have shown that, in the analysed region (about 10mm under the palm skin), there are several anatomic elements (including hand bones, bending tendons, muscle tissue, blood vessels) that can be exploited for measurements of biometric parameters. The characteristics of the proposed technique are compared with those of the 2D optical hand geometry, which is a well established biometric technique, and its possible advantages are underlined and discussed.

[Hepatopulmonary syndrome: case report and literature review]

Hepatopulmonary syndrome is an important complication of chronic liver disease occurring in 16 24% of patients. It is characterized by an increase in alveolar -capillary gradient, with or without hypoxemia, due to intrapulmonary vasodilatation. The course of the disease is progressive and associated with increased morbidity and mortality. There is no effective medical treatment and liver transplant is a priority. To exemplify the authors present the case of a 39 year -old male patient sent to the Pulmonology outpatient clinic and presenting with secondary polycythemia and progressive exertional dyspnoea. Clinical investigation identified a hepatopulmonary syndrome.

Large mediastinal thoracic duct cyst

Thoracic duct cysts of the mediastinum are extremely rare. The etiology is related to a congenital or degenerative weakness in the wall of the thoracic duct. Symptoms may arise from compression of adjacent structures. Surgical resection is recommended and allows a definitive histological diagnosis. Postoperative chylothorax is the most frequent complication. We describe a 30-year-old female who presented to us with a history of dry cough and hiccups within the last four months.

Max Frei theory revisitation: does really strokes depth change along time?

A serious problem in questioned document examination is to establish the age of written lines. With respect to paper dating, in the past, Max Frei theory (based only on microscope analysis) claimed that strokes are time-dependent. Therefore, according to this theory, it has been asserted that from the analysis of the strokes depth changes it is possible to try to date the handwritten document (to find out that the document is older than ...). In the present work, we investigate the strokes depth change by a laser profilometer considering not only the time but also microclimatic variations. First, we analyze the stability of stroke characteristics along the time. In particular, we demonstrate that if the document is preserved without change of temperature and humidity, the depth of the strokes has not appreciable changes. In this way, we have the purpose to verify the real possibility of documents dating by means of Max Frei theory. Subsequently, we test how the 3D profile of strokes changes in connection with the microclimatic variations. In particular, we test humidity variations. With this experiment, we show that humidity variations reduce the strokes depth. Moreover, this effect shows a non-linear trend, leaving a hysteresis on the depth. Finally, we show that the analysis of 3D stroke profile is unable to determine the age of documents.

[SAPHO syndrome--clinical report]

SAPHO Syndrome (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis) was first described in the 80s by Chamot and Kahn. This disease affects both skin and bones, mainly in the costal area and anterior chest wall (Skin-Bone Disease). Clinical symptoms vary according to the age of onset and response to the treatment is uncertain. This is considered a rare disease, although its real prevalence is not known. SAPHO syndrome may occur in any age and both sexes are equally affected. In this article, we present a case of SAPHO Syndrome and review the most relevant aspects of the literature.

Location response to a startling noise depends on the preferred grooming site in mice

The exploratory behavior of adult male Balb/c mice was observed in both a small black box and an open field. The normal exploratory pattern included a strong tendency to groom in a preferred place (G-site); thus, an average of 86% (black box) and 92% (open field) of the total grooming time was spent in a single location, specific for each animal and environment. The response of the animals to a 2-sec, 100 dB auditory stimulus varied according to their location. If the unexpected sound occurred when the mice were in their G-site, they remained there an average of 67% (black box) and 75% (open field) of the trials. If elsewhere, they escaped and ran to their G-site 89% (black box) and 73% (open field) of the times. Mice treated with diazepam (5 mg/kg) showed the normal tendency to groom in a preferred place, but never escaped after the stimulus, even if it occurred when they were outside their G-site, nor did they resume normal exploratory behavior. It seems that the preferred grooming location is the place that serves as a refuge from an aversive noise signal, but only the latter behavior is abolished by diazepam, presumably by reduction of stress.