This article discusses a concept for design and development of an Internet of Things (IoT) communication module of a multi- sensor early fire detection system and notification system. A SIM800F Global System for Mobile Communication (GSM) module is used to send fire alerts to owners of the shops, security guards via SMS and web- based fire notification subsystem in real- time. The web-based notification system is intended for remote notification of fire alerts, allows fire and rescue crew to receive notifications of a fire outbreak in real time. The system is implemented in three layers; sensing subsystem, data processing and storage and notification sub system. Raspberry Pi 3 has been used to control multiple Arduino which are integrated with a couple of sensors, the sensor threshold value is set and if exceeded then a n alarm is triggered and notification sent to the user via mobile application

In this research, a flexible inkjet-printed temperature sensor with in-house silver nanoparticles ink is presented and compared with the sensor printed with commercial silver nanoparticles ink. These sensors have an average width of 0.5±0.04 mm in the latter and 0.5±0.03 mm in the former. These serpentine structure sensors was printed on polyethylene terephthalate (PET) substrate by using Fujifilm Dimatix 2850 printer. The corresponding results indicated in resistance have been recorded in the range of 30-100°C to evaluate the sensor performance. The result of the studies showed that there was a linear relationship between the resistance and temperature for both ink types. The printed sensors developed using the in-house ink presented higher sensitivity 0.1086 Ω/^oc compared to the commercial ink which was 0.0543 Ω/^oc. Therefore, the flexible inkjet-printed temperature sensor with the in-house silver nanoparticles ink is recommended for the large-scale productions and implementations.

Schizophrenia (SCZ) is a chronic mental disorder that affects 23 million people worldwide. Clozapine (CLZ) is the most effective antipsychotic medication for treatment-resistant SCZ patients. Despite the superior efficacy of CLZ, it is dramatically underutilized due to the unavailable objective tests to measure CLZ efficacy. Several redox biomarkers in the blood have been correlated to CLZ efficacy. Yet, existing analytical methods change the levels of the molecules, their redox state, and eventually destroy the sample. By bridging the analytical gap and profiling the redox biomarkers, rapid and accurate CLZ treatment efficacy monitoring can be provided. Our overall goal is to develop a novel intelligent electrochemical biosensor based on an array of microelectrodes for CLZ treatment efficacy analysis. Here, we present the fabrication of the microelectrodes array, modification of the array with diffusion-limiting films, and characterization of the film’s effect on the generated electrochemical activity. The novelty of the biosensor lies within an array of microelectrodes modified with the positively charged biopolymer chitosan generating a set of complex electrochemical signals that are analyzed by using intelligent chemometric models. To achieve our goal, we microfabricated an array of 24 gold microelectrodes (100-µm-diameter working and 1,500-µm-diameter counter electrodes) by using photolithography and thin film deposition techniques. We used a 1.2% chitosan solution and applied cathodic current to electrodeposit thin films of chitosan onto the microelectrodes. To fabricate chitosan films with similar thicknesses and different densities, we measured the relationship between the thickness of the electrodeposited film and the applied electrodeposition current for 90s and 180s durations. A similar wet chitosan thickness (57.6±0.8 µm) was successfully achieved with 510 nA for 90s and 950 nA for 180s durations. Moreover, different dry chitosan thicknesses were obtained for 90s (10.7±0.1 µm) and 180s (13.2±0.6 µm) durations. Therefore, we calculated the porosity of the electrodeposited films as the ratio between the thicknesses of the wet and the dry films (5.38±0.09 and 4.36±0.20 at 510 nA for 90s and 950 nA for 180s, respectively). Furthermore, we used cyclic voltammetry to characterize the permeability of the modified films by measuring the ratio of the electrochemical signals generated from differently charged redox molecules (negatively charged ferrocyanide, neutral ferrocene, and positively charged hexaammineruthenium) before and after the modification. Statistical T-test analysis of the resulted permeabilities revealed significant differences for the charged molecules (P=0.85% for ferrocyanide; P=4.57% for hexaammineruthenium), while no significant difference was observed for the neutral molecule ferrocene. By providing a new way to analyze molecular profiles in blood, we anticipate establishing a new detection scheme for CLZ treatment efficacy that will help to transform schizophrenia management.

Acoustic leaky-wave antennas (ALWAs) have demonstrated the capacity to steering directive sound waves in frequency-dependent directions, due to the inherent dispersive radiation characteristic of leaky modes. Compared to more conventional uniform linear array (ULA) acoustic traducers for electronic beam steering (which rely on multiple sensors), the ALWA allows for single microphone operation. Thus ALWAs offer a direct mechanism to scan a directive acoustic beam in the angular space by simply sweeping the operating frequency of the acoustic signal, which envisions cost-efficient single-transducer direction finders for SONAR applications.

In this paper we study for the first time, some important features of an ALWA for acoustic underwater Direction-of-Arrival (DoA) estimation applications. First, we study the DoA estimation resolution of a practical ALWA for the first time, following similar direction-finding techniques recently applied for low-cost frequency-scanned LWA radars. Also, we analyze the capacity to reduce the Side Lobe Level (SLL) for enhanced performance, demonstrating aperture tapering techniques to the ALWA for the first time. Besides, also the effect of non-stationary and broadband signals (sine-sweep) in the generation of the directive beams is analyzed, since rapid angular frequency-beam-scanning techniques request for switching among different frequency channels with short duration pulse, or alternatively fast FMCW (Frequency-Modulated Continuous Wave) chirp slopes. Finally, we study the possible non-linear effects (parametric effect) that may arise in the propagation of different frequencies beams with some deviation thereof, which can lead to the long-range propagation of narrow directive low-frequency beams.

All these aspects are of much interest for real applications of ALWA in innovative SONAR systems for underwater scenarios.

Magnetic systems for position and orientation detection are typically based on the relative motion of a permanent magnet with respect to a magnetic field sensor. On one hand, features such as high resolution, contactless (and thus wear-free) measurement, low power consumption, robustness against temperature and contamination as well as low cost make them appealing for several industrial applications, especially in the automotive sector. On the other hand, a major challenge is represented by their sensitivity to fabrication tolerances.

In this work we present an implementation of the novel magnetic 3-axis joystick system, which realizes all degrees of freedom using only a single 3D sensor and a single magnet. The use of 3D printing technology for the device manufacture makes this implementation – referred to as “mini Drive” – highly cost-efficient. The system design ensures a unique magnetic output signal for every mechanical state (5 tilt states, continuous rotation).

In order to cope with the fabrication tolerances without resorting to a high-precision manufacture that would nullify the cost-efficiency of the mini Drive, we propose a novel calibration scheme based on analytical methods. This is done by using the analytical solution for the magnetic field – computed with the Magpylib package – and by applying a differential evolution algorithm, enabled by the fast analytical field computation, to solve a multivariate optimization problem including all relevant fabrication tolerances (as for instance the sensor position, the magnet position and magnetization, the maximum joystick’s rod tilt angles). The calibration procedure requires the measurement of only four points for each tilt with unknown rotational position, which makes it easy to apply for an end-user.

This novel scheme enables the calibration of more than 10 degrees of freedom within few seconds on conventional PCs and holds the potential to realize innovative, exotic and cost-efficient magnetic position systems.

Local Positioning Systems (LPS) are dependent on environmental characteristics, requiring an ad-hoc node deployment for each particular scenario of application for achieving practical results. Nonetheless, this Node Location Problem (NLP) has been assigned as NP-Hard, thus the application of heuristic algorithms is recommended for obtaining adequate solutions. Genetic Algorithms (GA) are widespread throughout the literature for solving NP-Hard combinatorial problems such as the NLP. However, GAs require the adjustment of a considerable amount of hyperparameters and can be easily compromised by premature convergence into local maximums. Therefore, in this paper, an approach based on local search methodologies, along with the GA optimization, is proposed. For this task, we apply a Memetic Algorithm based on a pseudo fitness function for reducing the problem complexity which analyses the neighboring solutions and introduces information into the optimization process. The exhaustive examination in a reduced space of solutions of this combination is idoneous for particularly adverse scenarios, thus improving the base optimization of the GA. We also perform a comparison of our method with different literature optimizations. Finally, we study the performance of the Memetic Algorithm (MA) proposed for different application scenarios, proving the effectiveness of our approach for irregular outdoor and urban context in which Non-Line-of-Sight (NLOS) conditions are considered.

Hematology tests, considered as an initial step in patient diagnostic process, require laboratory equipment and technicians which is a time and labor-consuming procedure. Such facilities may be available in a few central laboratories in under-resourced countries. The growing need for low cost and rapid diagnostic tests contributes to point-of-care (POC) medical diagnostic devices providing convenient and rapid test tools particularly in areas with limited medical resources. In the present study, a comprehensive numerical simulation of POC blood cell separation has been modeled using a finite element method. Tag-less separation of blood cells i.e. platelets, red blood cells, and white blood cells was carried out using standing surface acoustic waves (SSAWs) generated by interdigital transducers (IDTs) located at lateral sides of the microfluidic channel. Blood sample intake along with sheath flow was introduced via two symmetrical tilted angle inlets and middle inlet, respectively. Different parameters like wave frequency, wave amplitude, medium flow rate, and microchannel dimensions were analyzed in order to find the best design and optimum condition of blood cell sorting inside the device. Superposition of acoustic radiation force applied by SSAWs accompanied by drag force caused by medium flow drove the blood cells toward different path lines correlated to their size. Red and white blood cells were sorted out through separate locations in the middle outlet and, platelets were sorted out through the side outlets. Each cell then guided to their respected visualization chamber for further image processing analysis. The results of the presented numerical study would be very promising in designing and optimizing the POC blood testing device.

Fiber-optic sensors have been developed and improved upon for over a decade. Due to their versatility, they are used in numerous fields, such as industry, science or medicine. Introduction of an optical microsphere with zinc oxide (ZnO) coating applied by Atomic Layer Deposition (ALD) on its surface, allows for constant monitoring of the integrity of the structure. This feature is especially important during long-term measurements and sensing in the remote and hard-to-reach places. This study presents preparation of the microsphere-based fiber-optic sensor, characterization of the ALD ZnO coatings and an experimental setup operating as an interferometer in reflective mode, which was used to obtain the results of refractive index and temperature measurements. The signal generated by a low-coherent light source passes through an optical coupler to a microsphere-based fiber-optic sensor head, placed in a measured medium, where it reflects and travels to a detector. Interferometric signal is used to control whether the microstructure is whole. The intensity of reflected signal is used to conclude changes in measured parameter. By changing the value of a measured parameter, either refractive index or temperature, the intensity of a reflected signal also changes. The R² coefficient of each of presented sensors indicates a good linear fit of over 0.99 to the obtained data. Sensitivity of the sensors, investigated in this study, equals 103.5 nW/°C and 384uW/RIU for temperature and refractive index measurements, respectively.

Condition monitoring (CM) is an important application in industry for detecting machine failures in an incipient stage. Based on sensor data, computational intelligence methods provide efficient solutions for the analysis of high dimensional process data with the ability to detect and predict complex condition states. IOT gateways are affordable devices with the allow to implement data ingestion and data analytics task on an edge device providing the possibility to implement condition monitoring in real-time on the device.

In this work, we present an experimental bench for the sensorization of a hydraulic installation based on IOT gateways in order to detect several blocking states in a hydraulic pump and to avoid the cavitation problem. The experiments of 15 different blocking conditions yield a novel dataset with process sensor information for the described problem. The dataset is analyzed from a data curation point of view to find a meaningful categorization of fault conditions, which are feasible to be implemented in a condition monitoring system. We use an exploratory data analysis approach, which is based on principal component analysis provides data visualization of the 15 blocking conditions of the experiment, and allows us to decide on a proper fault categorization by detecting clearly separated data groups.

The environmental sanitation is very essential for healthy living. In our daily livelihood, garbage bins are usually kept without proper monitoring until they are being filled and overflow on the surrounding and spills out resulting in environmental pollution which has a serious health related issues to human beings and the environment. For smart cities, the garbage bins needs to be monitored and controlled to ensure healthy and clean environment. In the present technological advancement, real-time monitoring and control of waste disposal is a challenging area which needs an urgent attention by the research community. The traditional approach of monitoring waste in garbage bins placed in strategic locations is a very tedious and inefficient way that consume time, human effort, cost, and this is not in agreement with smart cities requirements. This research paper presents the design and implementation of an IoT-based Arduino microcontroller working with the ultrasonic sensors that detects the level of waste in the garbage bin placed from garbage locations and constantly at regular intervals display the status information as filled, half-filled or empty on an LCD screen, as well as send the content level information at those intervals to a central web-server system that displays the garbage bin levels graphically. This is achieved using a microcontroller, Wifi-module and ultrasonic sensors. The programming of the Arduino uno microcontroller was done with an Arduino IDE and embedded C programming language. The communication with the web-server was done using the hypertext pre-processor (PHP) scripting language. The prototype was designed and simulated using Proteus 8.0 professional simulator software. This process helps to automate garbage bin monitoring and control. Experimental results demonstrate a promising solution to waste management and control. A number of runnings and testing had been performed to evaluate the device workability in real situation. The measured distance from the garbage bins are transmitted to the website. This webpage performs analytic and visualization and displays a barchart showing the levels of the garbage waste, time, and location in real-time for viewing. The proposed approach is an innovative system which will helps to keep the smart cities clean using ultrasonic sensors.