The Borexino detector at the Laboratori Nazionali del Gran Sasso

Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the real-time measurement of sub MeV solar neutrinos, and particularly of the mono energetic (862 keV) Be7 electron capture neutrinos, via neutrino-electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography).Comment: 37 pages, 43 figures, to be submitted to NI

Hydraulic Performance of Lined Permeable Pavement Systems in the Built Environment

The hydraulic performance of permeable pavement (PP) systems has been well demonstrated when based on full or partial on-site infiltration, while there is only limited research on lined PP systems built to provide detention and volume reduction by evaporation only. In this study, we tested the performance of commercially available PP components when constructed as lined PP systems with un-throttled discharge to explore basic hydraulic function in a real-life-setting. Four types of PP surface products and three types of sub-base aggregates were tested in six unique combinations, built as side-by-side parking lots into an existing parking area, each stall having a size of 25 m2 and 0.5 m of depth with individual lining. Based on 12 months of monitoring precipitation and discharge from each stall, total volume reduction ranged from 3% to 37%. Analysis of up to 22 single events, representing return periods of up to two years, revealed marked detention capacities, expressed as median volume reduction of 40%, spanning 27–69% and median lag time of 1:38 h, spanning 0:39–3:16 h, across all stalls. The considerable range in hydraulic properties can be ascribed to both surface and sub-base properties

The EB66® cell line for yellow fever vaccine production at high cell concentrations

The global threat of the emerging yellow fever disease can be effectively countered by vaccination. First vaccines against yellow fever have been developed in embryonated chicken eggs in the 1930s and this production platform remained almost unchanged until today. However, recent outbreaks revealed vaccine supply shortages due to limiting options to ramp up production. Here, we present a cell culture-based process using EB66® cells for production of a live, attenuated yellow fever vaccine (YFV; WHO 17D-213/77 strain). The duck embryo-derived EB66® suspension cell line showed good growth performance in batch mode achieving up to 1.8 × 107 cells/mL and doubling times of less than 17 h in shake flasks in the chemically-defined CDM4Avian medium at 37°C. The seed virus material was adapted by five serial passages to the cell substrate, which resulted in an 8-fold increase in virus titer to 1.3 × 108 PFU/mL (infectious virions per mL). Changes in process temperature and cell disruption to facilitate virus release did not improve final virus titers. In a next step, the process was transferred into benchtop bioreactors equipped with an alternating tangential flow filtration unit (ATF2) operating at a working volume of 700 mL. An on-line conductivity probe was implemented, which enabled cell growth monitoring in real-time. This setup allowed to achieve high cell densities of up to 9.5 × 107 cells/mL resulting in a further increase of YFV titers up to 7.3 × 108 PFU/mL. Based on an input of 4.7 log infectious units per dose, raw virus material equivalent to 10 Mio vaccine doses was produced in less than two weeks operation time. Taken together, EB66® suspension cells can grow to very high cell densities in perfusion systems. Present process intensification clearly demonstrated the potential to produce millions of YFV vaccine doses from small scale cultures in a controllable and scalable manner

The EB66® cell line for yellow fever vaccine production at high cell concentrations

The global threat of the emerging yellow fever disease can be effectively countered by vaccination. First vaccines against yellow fever have been developed in embryonated chicken eggs in the 1930s and this production platform remained almost unchanged until today. However, recent outbreaks revealed vaccine supply shortages due to limiting options to ramp up production. Here, we present a cell culture-based process using EB66® cells for production of a live, attenuated yellow fever vaccine (YFV; WHO 17D-213/77 strain). The duck embryo-derived EB66® suspension cell line showed good growth performance in batch mode achieving up to 1.8 × 107 cells/mL and doubling times of less than 17 h in shake flasks in the chemically-defined CDM4Avian medium at 37°C. The seed virus material was adapted by five serial passages to the cell substrate, which resulted in an 8-fold increase in virus titer to 1.3 × 108 PFU/mL (infectious virions per mL). Changes in process temperature and cell disruption to facilitate virus release did not improve final virus titers. In a next step, the process was transferred into benchtop bioreactors equipped with an alternating tangential flow filtration unit (ATF2) operating at a working volume of 700 mL. An on-line conductivity probe was implemented, which enabled cell growth monitoring in real-time. This setup allowed to achieve high cell densities of up to 9.5 × 107 cells/mL resulting in a further increase of YFV titers up to 7.3 × 108 PFU/mL. Based on an input of 4.7 log infectious units per dose, raw virus material equivalent to 10 Mio vaccine doses was produced in less than two weeks operation time. Taken together, EB66® suspension cells can grow to very high cell densities in perfusion systems. Present process intensification clearly demonstrated the potential to produce millions of YFV vaccine doses from small scale cultures in a controllable and scalable manner

Robust moving horizon H∞ control of discrete time-delayed systems with interval time-varying delays

In this study, design of a delay-dependent type moving horizon state-feedback control (MHHC) is considered for a class of linear discrete-time system subject to time-varying state delays, norm-bounded uncertainties, and disturbances with bounded energies. The closed-loop robust stability and robust performance problems are considered to overcome the instability and poor disturbance rejection performance due to the existence of parametric uncertainties and time-delay appeared in the system dynamics. Utilizing a discrete-time Lyapunov-Krasovskii functional, some delay-dependent linear matrix inequality (LMI) based conditions are provided. It is shown that if one can find a feasible solution set for these LMI conditions iteratively at each step of run-time, then we can construct a control law which guarantees the closed-loop asymptotic stability, maximum disturbance rejection performance, and closed-loop dissipativity in view of the actuator limitations. Two numerical examples with simulations on a nominal and uncertain discrete-time, time-delayed systems, are presented at the end, in order to demonstrate the efficiency of the proposed method

STV-based Video Feature Processing for Action Recognition

In comparison to still image-based processes, video features can provide rich and intuitive information about dynamic events occurred over a period of time, such as human actions, crowd behaviours, and other subject pattern changes. Although substantial progresses have been made in the last decade on image processing and seen its successful applications in face matching and object recognition, video-based event detection still remains one of the most difficult challenges in computer vision research due to its complex continuous or discrete input signals, arbitrary dynamic feature definitions, and the often ambiguous analytical methods. In this paper, a Spatio-Temporal Volume (STV) and region intersection (RI) based 3D shape-matching method has been proposed to facilitate the definition and recognition of human actions recorded in videos. The distinctive characteristics and the performance gain of the devised approach stemmed from a coefficient factor-boosted 3D region intersection and matching mechanism developed in this research. This paper also reported the investigation into techniques for efficient STV data filtering to reduce the amount of voxels (volumetric-pixels) that need to be processed in each operational cycle in the implemented system. The encouraging features and improvements on the operational performance registered in the experiments have been discussed at the end

ECG Signal Reconstruction on the IoT-Gateway and Efficacy of Compressive Sensing Under Real-time Constraints

Remote health monitoring is becoming indispensable, though, Internet of Things (IoTs)-based solutions have many implementation challenges, including energy consumption at the sensing node, and delay and instability due to cloud computing. Compressive sensing (CS) has been explored as a method to extend the battery lifetime of medical wearable devices. However, it is usually associated with computational complexity at the decoding end, increasing the latency of the system. Meanwhile, mobile processors are becoming computationally stronger and more efficient. Heterogeneous multicore platforms (HMPs) offer a local processing solution that can alleviate the limitations of remote signal processing. This paper demonstrates the real-time performance of compressed ECG reconstruction on ARM's big.LITTLE HMP and the advantages they provide as the primary processing unit of the IoT architecture. It also investigates the efficacy of CS in minimizing power consumption of a wearable device under real-time and hardware constraints. Results show that both the orthogonal matching pursuit and subspace pursuit reconstruction algorithms can be executed on the platform in real time and yield optimum performance on a single A15 core at minimum frequency. The CS extends the battery life of wearable medical devices up to 15.4% considering ECGs suitable for wellness applications and up to 6.6% for clinical grade ECGs. Energy consumption at the gateway is largely due to an active internet connection; hence, processing the signals locally both mitigates system's latency and improves gateway's battery life. Many remote health solutions can benefit from an architecture centered around the use of HMPs, a step toward better remote health monitoring systems.Peer reviewedFinal Published versio

Quantitative Verification: Formal Guarantees for Timeliness, Reliability and Performance

Computerised systems appear in almost all aspects of our daily lives, often in safety-critical scenarios such as embedded control systems in cars and aircraft or medical devices such as pacemakers and sensors. We are thus increasingly reliant on these systems working correctly, despite often operating in unpredictable or unreliable environments. Designers of such devices need ways to guarantee that they will operate in a reliable and efficient manner. Quantitative verification is a technique for analysing quantitative aspects of a system's design, such as timeliness, reliability or performance. It applies formal methods, based on a rigorous analysis of a mathematical model of the system, to automatically prove certain precisely specified properties, e.g. ``the airbag will always deploy within 20 milliseconds after a crash'' or ``the probability of both sensors failing simultaneously is less than 0.001''. The ability to formally guarantee quantitative properties of this kind is beneficial across a wide range of application domains. For example, in safety-critical systems, it may be essential to establish credible bounds on the probability with which certain failures or combinations of failures can occur. In embedded control systems, it is often important to comply with strict constraints on timing or resources. More generally, being able to derive guarantees on precisely specified levels of performance or efficiency is a valuable tool in the design of, for example, wireless networking protocols, robotic systems or power management algorithms, to name but a few. This report gives a short introduction to quantitative verification, focusing in particular on a widely used technique called model checking, and its generalisation to the analysis of quantitative aspects of a system such as timing, probabilistic behaviour or resource usage. The intended audience is industrial designers and developers of systems such as those highlighted above who could benefit from the application of quantitative verification,but lack expertise in formal verification or modelling