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We present a high-frequency, tunable, piezoelectric MEMS resonant scanner producing an optical scan angle of more than 2° at frequencies above 100 kHz, with non-contact frequency tuning capabilities. The device is fabricated using a cost-efficient multiuser silicon-on-insulator (SOI) process. The scanner uses thin-film piezoelectric aluminium nitride actuators to drive out-of-plane rotation of a 200 µm diameter mirror plate through mechanical coupling stages. Up to 3.6 kHz frequency tuning is achieved through on-chip thermally actuated non-contact beam tips placed adjacent to the scanner. The scanner is intended for use in small-scale, fast optomechanical applications requiring careful synchronization through frequency tuning.

In this paper, we provide an overview of the sixth annual edition of the CLEF eHealth evaluation lab. CLEF eHealth 2018 continues our evaluation resource building efforts around the easing and support of patients, their next-of-kins, clinical staff, and health scientists in understanding, accessing, and authoring eHealth information in a multilingual setting. This year’s lab offered three tasks: Task 1 on multilingual information extraction to extend from last year’s task on French and English corpora to French, Hungarian, and Italian; Task 2 on technologically assisted reviews in empirical medicine building on last year’s pilot task in English; and Task 3 on Consumer Health Search (CHS) in mono- and multilingual settings that builds on the 2013–17 Information Retrieval tasks. In total 28 teams took part in these tasks (14 in Task 1, 7 in Task 2 and 7 in Task 3). Herein, we describe the resources created for these tasks, outline our evaluation methodology adopted and provide a brief summary of participants of this year’s challenges and results obtained. As in previous years, the organizers have made data and tools associated with the lab tasks available for future research and development.

We propose and demonstrate an all-fiber passively mode-locked laser with pulsed cylindrical vector beam output based on a mode selective coupler (MSC) in a figure-8 cavity, The MSC made of a two mode fiber and a standard single mode fiber is used as both the intracavity transverse mode converter and mode splitter. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity which are measured to be > 94%. The mode-locked laser pulses have duration of 17 ns and a repetition rate of 0.66 MHz, operating near a wavelength of 1556.3 nm with a spectral bandwidth of 3.2 nm.

With the purpose of automatic detection of crowd patterns including abrupt and abnormal changes, a novel approach for extracting motion “textures” from dynamic Spatio-Temporal Volume (STV) blocks formulated by live video streams has been proposed. This paper starts from introducing the common approach for STV construction and corresponding Spatio-Temporal Texture (STT) extraction techniques. Next the crowd motion information contained within the random STT slices are evaluated based on the information entropy theory to cull the static background and noises occupying most of the STV spaces. A preprocessing step using Gabor filtering for improving the STT sampling efficiency and motion fidelity has been devised and tested. The technique has been applied on benchmarking video databases for proof-of-concept and performance evaluation. Preliminary results have shown encouraging outcomes and promising potentials for its real-world crowd monitoring and control applications.

Key feature of a context-aware application is the ability to adapt based on the change of context. Two approaches that are widely used in this regard are the context-action pair mapping where developers match an action to execute for a particular context change and the adaptive learning where a context-aware application refines its action over time based on the preceding action’s outcome. Both these approaches have limitation which makes them unsuitable in situations where a context-aware application has to deal with unknown context changes. In this paper we propose a framework where adaptation is carried out via concurrent multi-action evaluation of a dynamically created action space. This dynamic creation of the action space eliminates the need for relying on the developers to create context-action pairs and the concurrent multi-action evaluation reduces the adaptation time as opposed to the iterative approach used by adaptive learning techniques. Using our reference implementation of the framework we show how it could be used to dynamically determine the threshold price in an e-commerce system which uses the name-your-own-price (NYOP) strategy.

Health services worldwide are seeking ways to improve patient care for amputees suffering from diabetes, and at the same time reduce costs. The monitoring of residual limb temperature, interface pressure and gait can be a useful indicator of tissue viability in lower limb amputees especially to predict the occurrence of pressure ulcers. This is further exacerbated by elevated temperatures and humid micro environment within the prosthesis which encourages the growth of bacteria and skin breakdown. Wearable systems for prosthetic users have to be designed such that the sensors are minimally obtrusive and reliable enough to faithfully record movement and physiological signals. A mobile sensor platform has been developed for use with the lower limb prosthetic users. This system uses an Arduino board that includes sensors for temperature, gait, orientation and pressure measurements. The platform transmits sensor data to a central health authority database server infrastructure through the Bluetooth protocol at a suitable sampling rate. The data-sets recorded using these systems are then processed using machine learning algorithms to extract clinically relevant information from the data. Where a sensor threshold is reached a warning signal can be sent wirelessly together with the relevant data to the patient and appropriate medical personnel. This knowledge is also useful in establishing biomarkers related to a possible deterioration in a patient’s health or for assessing the impact of clinical interventions.

This study investigates an effect of autofrettage on the fatigue and corrosion fatigue life of high pressure parts made from low carbon structural steel. To estimate the beneficial effect of autofrettage application, an extensive experimental program and advanced theoretical modelling are conducted and analyzed in this study. Accurate calculation of compressive residual stresses is achieved by application of a cyclic plasticity model which can precisely simulate a cyclic plasticity response of material. In terms of a fatigue life prediction methodology, a non-local stress based approach with a modified critical distance theory is used for prediction of the crack initiation stage providing conservative fatigue assessment. Because of the fact that the crack propagation stage can take a considerable part of the total life for autofrettaged parts, more accurate fatigue life calculation is performed by the use of a fracture mechanics approach. The total fatigue life time of autofrettaged parts is then calculated as a sum of the crack initiation and propagation stages.

This paper presents preliminary results for metal-packaged fiber Bragg grating strain and temperature sensors designed specifically for structural health monitoring in civil engineering applications. The laboratory experiments show that the in-house manufactured metal-packaged sensors are sufficiently resilient, under dynamic loading, to successfully undergo a million cycle fatigue test without adverse deterioration in performance. In addition, from the thermal characterization of the devices, a conclusion can be drawn that the metal-packaged sensors offer superior performance over sensors assembled using epoxy bonding. These early results are very promising, inspiring confidence in the adopted methodologies, and giving the mandate to proceed with more detailed laboratory testing to evaluate reliability and lifetime of the transducers in the future work.