A Feedback-Based Pneumatic Compression System for Effective Lymphedema Management

Bioimpedance analysis (BIA) is a method of detecting lymphedema- a debilitating medical condition involving swelling of the extremities. Pneumatic compression devices are frequently used in the compression treatment of lymphedema. Although existing compression technology provides relief of symptoms, it has limitations in terms of ease-of-use, portability, and monitoring of treatment progress. Currently, there are no BIA analyzers in the market that run on a low-power microcontroller and a rechargeable battery. Moreover, no such device currently exists that integrate the BIA analysis with pneumatic compression system to offer a feedback-based solution for lymphedema treatment. This work represents the first steps towards a complete system and describes the pneumatic compression and circuit designs for a portable BIA analyzer. The study proposes a lightweight, battery operated pneumatic compression device that can apply a pressure of 50 mmHg in a four-chamber compression garment. A microcontroller-based BIA system that can provide accurate indication of swelling based on a Nyquist plot was introduced. The envisioned mechatronic system features programmable compression sequences and operates with the human-in-the-loop using bioimpedance spectroscopy as control feedback. Performance of the compression system is verified by measurement of applied pressures and the BIA circuits are validated for single frequency and multi frequency impedance analysis of a phantom test load. With further development in the future, the system has the potential to serve as a quantitative source of valuable diagnostic information for clinicians, and in the long run may enable the smart management of lymphedema with the device essentially prescribing the course of treatment in response to measured conditions. This kind of human-in-the-loop control system may be a breakthrough in treatment of chronic conditions

An Arduino microcontroller based RLC meter

An RLC meter is a single electronic instrument or device which is capable to measure the Resistance (R), Inductance (L) and Capacitance (C). This instrument has wide applications in electrical and electronics laboratory, industry and engineering research works. Nowadays, a large variety of RLC meter is available. The high precision RLC meter is slow responding, bulky size, higher operational power and expensive. However, many applications do not need very high accuracy measurement, for this reason, this paper has proposed a simple and moderate precision RLC meter based on Arduino microcontroller which would overcome the existing issues. The proposed design has been verified by simulation and experimentally. The results show good compliance with theory and experiment; in addition, it shows moderate accuracy

Miniature Resistance Measurement Device for Structural Health Monitoring of Reinforced Concrete Infrastructure

A vast amount of civil infrastructure is constructed using reinforced concrete, which can be susceptible to corrosion, posing significant risks. Corrosion of reinforced concrete has various causes, with chloride ingress known to be a major contributor. Monitoring this chloride ingress would allow for preventative maintenance to be less intrusive at a lower cost. Currently, chloride sensing methods are bulky and expensive, leaving the majority of concrete infrastructures unmonitored. This paper presents the design and fabrication of a miniature, low-cost device that can be embedded into concrete at various locations and depths. The device measures localized concrete resistance, correlating to the chloride ingress in the concrete using equations listed in this paper, and calculated results from two experiments are presented. The device benefits from a four-probe architecture, injecting a fixed frequency AC waveform across its outer electrodes within the cement block. Voltage across the internal electrodes is measured with a microcontroller and converted to a resistance value, communicated serially to an external computer. A final test showcases the ability of the device for three-dimensional mass deployment

Implementasi Alat Ukur Kapasitansi Digital (Digital Capacitance Meter) berbasis Mikrokontroler

Intisari – Kapasitansi Meter merupakan alat yang penting bagi seorang perancang elektronika, karena sangat berguna dalam perancangan dan pembuatan suatu rangkaian elektronika yang membutuhkan keakuratan nilai kapasitansi dari kapasitor yang digunakan. Pada penelitian ini dilakukan perancangan dan implementasi sebuah alat ukur kapasitansi secara digital (digital capacitance meter) menggunakan  mikrokontroler.  Kata kunci --  Alat ukur Kapasitansi, digital, Mikrokontroler, Kapasitansi meter digitalAbstract - Capacitance meter is an important device for an electronic designer, since it is useful for designing an electronic circuits that need the accurate value of capacitor. The project is aimed to design and implement a digital capacitance meter by using microcontroller.Keywords --  Capacitance Meter, digital, Microcontroller, digital capacitance mete

Content-based indexing of low resolution documents

In any multimedia presentation, the trend for attendees taking pictures of slides that interest them during the presentation using capturing devices is gaining popularity. To enhance the image usefulness, the images captured could be linked to image or video database. The database can be used for the purpose of file archiving, teaching and learning, research and knowledge management, which concern image search. However, the above-mentioned devices include cameras or mobiles phones have low resolution resulted from poor lighting and noise. Content-Based Image Retrieval (CBIR) is considered among the most interesting and promising fields as far as image search is concerned. Image search is related with finding images that are similar for the known query image found in a given image database. This thesis concerns with the methods used for the purpose of identifying documents that are captured using image capturing devices. In addition, the thesis also concerns with a technique that can be used to retrieve images from an indexed image database. Both concerns above apply digital image processing technique. To build an indexed structure for fast and high quality content-based retrieval of an image, some existing representative signatures and the key indexes used have been revised. The retrieval performance is very much relying on how the indexing is done. The retrieval approaches that are currently in existence including making use of shape, colour and texture features. Putting into consideration these features relative to individual databases, the majority of retrievals approaches have poor results on low resolution documents, consuming a lot of time and in the some cases, for the given query image, irrelevant images are obtained. The proposed identification and indexing method in the thesis uses a Visual Signature (VS). VS consists of the captures slides textual layout’s graphical information, shape’s moment and spatial distribution of colour. This approach, which is signature-based are considered for fast and efficient matching to fulfil the needs of real-time applications. The approach also has the capability to overcome the problem low resolution document such as noisy image, the environment’s varying lighting conditions and complex backgrounds. We present hierarchy indexing techniques, whose foundation are tree and clustering. K-means clustering are used for visual features like colour since their spatial distribution give a good image’s global information. Tree indexing for extracted layout and shape features are structured hierarchically and Euclidean distance is used to get similarity image for CBIR. The assessment of the proposed indexing scheme is conducted based on recall and precision, a standard CBIR retrieval performance evaluation. We develop CBIR system and conduct various retrieval experiments with the fundamental aim of comparing the accuracy during image retrieval. A new algorithm that can be used with integrated visual signatures, especially in late fusion query was introduced. The algorithm has the capability of reducing any shortcoming associated with normalisation in initial fusion technique. Slides from conferences, lectures and meetings presentation are used for comparing the proposed technique’s performances with that of the existing approaches with the help of real data. This finding of the thesis presents exciting possibilities as the CBIR systems is able to produce high quality result even for a query, which uses low resolution documents. In the future, the utilization of multimodal signatures, relevance feedback and artificial intelligence technique are recommended to be used in CBIR system to further enhance the performance

Module-level power converters for parallel connected photovoltaic arrays

A new solar technology with the capability to increase array-level power production is introduced by using simple integrated power converters that connect directly to photovoltaic (PV) panels is investigated. The power converters proposed here are full-bridge DC-DC converters with high voltage gain that operate with an open-loop control scheme. The outputs of these converters could then be directly connected to a grid-tie converter eliminating the need to connect panels in series to achieve the appropriate voltage. With a high-efficiency converter, the total system efficiency would increase even though one panel in the array may be compromised. The simulation results show that a highly-efficient converter is possible. To assist in experimentation, an auxilary [sic] circuit using a microcontroller was implemented to supply power and gate signals to the gate driver of the power converters. The design and construction of a transformer for use with the full-bridge converter is discussed. A novel transformer topology is utilized to increase converter efficiency. The converters were tested both in a laboratory environment and outdoors for solar data collection. Transient response, source regulation and load regulation analysis was performed. The maximum power points of the array were investigated for different insolation levels. Even when insolation differs substantially, the panel output power levels are within their individual maximum power levels when the total output is maximized even without independent power trackers. Analysis of both field data and random insolation indicate that the new approach does increase power generation and therefore system efficiency --Abstract, page iii

HUMIDITY SENSOR CIRCUIT USING REAL TIME OPERATING SYSTEM (FREERTOS) KERNEL

A humidity sensor can be used to measure the moisture content of the environment. The physical change of the sensor expresses as the change of electrical property like capacitance, resistance, voltage, current, frequency, etc. In order to process these analog signals digitally, microprocessor is involved in the measurement. This thesis presents design of a circuit to measure low moisture levels. The 16-bit RISC mixed signal microcontroller MSP430F249 from Texas Instruments will be used. The circuit has good performance at extremely low humidity levels. Meanwhile, a small real time operating system kernel FreeRTOS, a market leading RTOS from Real Time Engineer Ltd is ported to the microcontroller. The basic concept about FreeRTOS and how to port this RTOS to MSP430F249 microcontrollers will be the topics of this thesis as well

Towards the development of a wearable temperature sensor based on a ferroelectric capacitor

Response of a ferroelectric capacitor to static temperature (~22 to 90°C) is presented. The sensor is based on ferroelectric ceramic lead zirconate titanate (PZT). The PZT sensor is a cheap, commercially available element used to provide a proof of concept for the initial investigation into using ferroelectric materials for the monitoring of static temperature. The capacitor response to temperature was measured using PZT capacitance changes recorded at 1 kHz. The capacitance was measured after the temperature had stabilised. We have found that the PZT capacitor responds linearly as a function of applied temperature, with a sensitivity ~ 53 pF/°C. Furthermore, to provide some initial electronics capable of measuring sensor capacitance in real time, the PZT element was attached to an Arduino Uno platform. Again, the sensor continues to respond linearly to temperature with a sensitivity of 146 pF/°C. The system developed paves the way for further work to be done on using ferroelectric materials for the monitoring of static temperature changes, for applications such as human body temperature measurement using a textile-based smart-shirt setup