Comprehensive design and propagation study of a compact dual band antenna for healthcare applications

In this paper, a dual band planar inverted F antenna (PIFA) has been investigated for cooperative on- and off-body communications. Free space and on-body performance parameters like return loss, bandwidth, radiation pattern and efficiency of this antenna are shown and investigated. The on- and off-body radio propagation channel performance at 2.45 GHz and 1.9 GHz have been investigated, respectively. Experimental investigations are performed both in the anechoic chamber and in an indoor environment. The path loss exponent has been extracted for both on- and off-body radio propagation scenarios. For on-body propagation, the path loss exponent is 2.48 and 2.22 in the anechoic chamber and indoor environment, respectively. The path loss exponent is 1.27 for off-body radio propagation situation. For on-body case, the path loss has been characterized for ten different locations on the body at 2.45 GHz, whereas for off-body case radio channel studies are performed for five different locations at 1.9 GHz. The proposed antenna shows a good on- and off-body radio channel performance

High efficiency and high gain non-isolated bidirectional dc-dc converter with soft switching capability

The non-isolated dc-dc power converters are considered as a unique option for flexible voltage control and adaptation in the modern energy conversion systems due to their simple and light configurations. To this date, these converters are primarily investigated to generate high efficiency and high gain with a sustained soft switching capability and a smaller footprint. On that account, this work proposes two effective solutions to address the aforementioned issues. First, a high-efficiency soft switching non-isolated bidirectional dc-dc converter with a simple configuration is proposed. The converter executes the zero voltage zero current switching (ZVZCS) over a wide operating region to ensure high efficiency. For verification, a 150 W experimental prototype is built and tested for soft switching performance by varying the input voltage, switching frequency and the loading. It is observed that the efficiency remains consistently high and has a full-load maximum of 98.2% in the boost mode and 97.5% in the buck mode. The analysis of the Electromagnetic Interference (EMI) performance of the converter also shows the improvement in the noise signature. Second, an improved high gain zero voltage switching (ZVS) nonisolated bidirectional dc-dc converter is proposed. The high gain is realized by using an intermediate energy storage cell with reduced size. Besides, the ZVS is implemented by two integrated auxiliary resonant networks. These networks ensure sustained ZVS operation over the entire duty ratio. A 200 W prototype is built to verify the concept. As a result, a full load efficiency of 97.5% (in boost mode) and 95.5% (in buck mode) is recorded at fs= 30 kHz. Also, these efficiencies are recorded as 97% (boost mode) and 94.5% (buck mode) at fs= 100 kHz. Moreover, it is observed that the efficiency (and so the soft switching) is consistent over the entire gain profile. However, there is a slight additional drop of 1.5% (boost mode) and 1% (buck mode) at extreme duty ratios. Both converters also implement soft switching for auxiliary switches and eliminate the reverse recovery loss

Experimental study of on-body radio channel performance of a compact ultra wideband antenna

In this paper, on-body radio channel performance of a compact ultra wideband (UWB) antenna is investigated for body-centric wireless communications. Measurement campaigns were first done in the chamber and then repeated in an indoor environment for comparison. The path loss parameter for eight different on-body radio channels has been characterized and analyzed. In addition, the path loss was modeled as a function of distance for 34 different receiver locations for propagation along the front part of the body. Results and analysis show that, compared with anechoic chamber, a reduction of 16.34% path loss exponent is noticed in indoor environment. The antenna shows very good on-body radio channel performance and will be a suitable candidate for future efficient and reliable body-centric wireless communications

Artificial intelligence approaches for advanced battery management system in electric vehicle applications : a statistical analysis towards future research opportunities

In order to reduce carbon emissions and address global environmental concerns, the automobile industry has focused a great deal of attention on electric vehicles, or EVs. However, the performance and health of batteries can deteriorate over time, which can have a negative impact on the effectiveness of EVs. In order to improve the safety and reliability and efficiently optimize the performance of EVs, artificial intelligence (AI) approaches have received massive consideration in precise battery health diagnostics, fault analysis and thermal management. Therefore, this study analyzes and evaluates the role of AI approaches in enhancing the battery management system (BMS) in EVs. In line with that, an in-depth statistical analysis is carried out based on 78 highly relevant publications from 2014 to 2023 found in the Scopus database. The statistical analysis evaluates essential parameters such as current research trends, keyword evaluation, publishers, research classification, nation analysis, authorship, and collaboration. Moreover, state-of-the-art AI approaches are critically discussed with regard to targets, contributions, advantages, and disadvantages. Additionally, several significant problems and issues, as well as a number of crucial directives and recommendations, are provided for potential future development. The statistical analysis can guide future researchers in developing emerging BMS technology for sustainable operation and management in EVs. © 2023 by the authors

Feasibility analysis of floating photovoltaic power plant in Bangladesh: A case study in Hatirjheel Lake, Dhaka

The installation of large-scale photovoltaic (LSPV) power plants is a solution to mitigate the national energy demand in Bangladesh. However, the land crisis is one of the key challenges for the rapid growth of ground-mounted LSPV plants in Bangladesh. The per unit cost of energy from ground-mounted PV systems is rising as a response to numerous difficulties, particularly for large-scale electricity generation. To overcome the issues with land-based PV, the floating photovoltaic (FPV) could be a viable solution. To the aspirations of the Sustainable and Renewable Energy Development Authority (SREDA), this article has investigated the feasibility of constructing a floating solar plant at Hatirjheel Lake in Dhaka, Bangladesh. The lake is an excellent spot to build an FPV plant due to its geographic location and climatic conditions inside the capital city. In this paper, the design of the plant and tariff are carried out using the PVsyst simulator. It is found that the optimum cost of energy for the plant is $ 0.0959/KWh, which is lesser than the currently operational ground-mounted PV plants in Bangladesh. Additionally, the projected 6.7 MW plant can meet 12.5 % of the local energy demand. Furthermore, the FPV plant is capable to cut off 6685 tons of CO2 annually. A reduction in power costs and environmental protection would assist the government of Bangladesh in achieving the sustainable development goals and electricity generation target of 6000 MW from solar photovoltaics by 2041 as well

The Effects of Non-Uniformly-Aged Photovoltaic Array on Mismatch Power Loss: A Practical Investigation towards Novel Hybrid Array Configurations

One of the most important causes of a reduction in power generation in PV panels is the non-uniform aging of photovoltaic (PV) modules. The increase in the current–voltage (I–V) mismatch among the array modules is the primary cause of this kind of degradation. There have been several array configurations investigated over the years to reduce mismatch power loss (MPL) caused by shadowing, but there have not been any experimental studies that have specifically examined the impact of various hybrid array topologies taking PV module aging into consideration. This research examines the influence of the non-uniform aging scenario on the performance of solar PV modules with various interconnection strategies. Experiments have been carried out on a 4 × 10, 400 W array with 12 possible configurations, including three proposed configurations (LD-TCT, SP-LD, and LD-SP), to detect the electrical characteristics of a PV system. Finally, the performances of different module configurations are analyzed where the newly proposed configurations (SP-LD and LD-SP) show 15.80% and 15.94% higher recoverable energy (RE), respectively, than the most-adopted configuration (SP). Moreover, among the twelve configurations, the SP configuration shows the highest percentage of MPL, which is about 17.96%, whereas LD-SP shows the lowest MPL at about 4.88%

The effects of non-uniformly-aged photovoltaic array on mismatch power loss : A practical investigation towards novel hybrid array configurations

One of the most important causes of a reduction in power generation in PV panels is the non-uniform aging of photovoltaic (PV) modules. The increase in the current–voltage (I–V) mismatch among the array modules is the primary cause of this kind of degradation. There have been several array configurations investigated over the years to reduce mismatch power loss (MPL) caused by shadowing, but there have not been any experimental studies that have specifically examined the impact of various hybrid array topologies taking PV module aging into consideration. This research examines the influence of the non-uniform aging scenario on the performance of solar PV modules with various interconnection strategies. Experiments have been carried out on a 4 × 10, 400 W array with 12 possible configurations, including three proposed configurations (LD-TCT, SP-LD, and LD-SP), to detect the electrical characteristics of a PV system. Finally, the performances of different module configurations are analyzed where the newly proposed configurations (SP-LD and LD-SP) show 15.80% and 15.94% higher recoverable energy (RE), respectively, than the most-adopted configuration (SP). Moreover, among the twelve configurations, the SP configuration shows the highest percentage of MPL, which is about 17.96%, whereas LD-SP shows the lowest MPL at about 4.88%

SPECKLE NOISE REDUCTION FROM MEDICAL ULTRASOUND IMAGES USING WAVELET THRESHOLDING AND ANISOTROPIC DIFFUSION METHOD

ABSTRACT Medical Images are very often corrupted by various types of noise including speckle noise, salt and pepper noise etc. This corruption of noise is introduced to the original image during image acquisition and transmission. The various image denoising techniques that are proposed from time to time are offering denoising techniques preserving the original image features. The denoising is so important because ultrasound imaging today has gained wide acceptance due to its safety, easy imaging procedure, low cost and adaptability. However the main shortcomings of this process is poor quality of images which is further degraded due to the presence of speckle noise and other types of noise. Hence it has become vital to remove noise while preserving important datails and features of the image. This paper will introduce a unique method to speckle noise filtering using median filters, wavelet and SRAD filters

Comparison of Rectangular and Circular Microstrip Fed Patch Antennas at 5.76 GHz

A Comparative study of rectangular and circular shape microstrip patch antennas at 5.76 GHz band is presented in this paper. Computer Simulation Technology (CST) microwave studio is used as the software environment to design and compare the performance of the antennas. Based on the results and analysis, it is found that rectangular patch antenna shows about 8 dB higher return loss then return loss of circular patch antenna. In addition, rectangular patch antenna has improved gain value of 7.499 dB then that of the circular patch with gain 7.114 dB. The radiation efficiency of both rectangular and circular shaped microstrip fed patch antennas is nearly the same. &nbsp

A skipping adaptive P&O MPPT for fast and efficient tracking under partial shading in PV arrays

This work presents a new Maximum Power Point Tracking (MPPT) scheme which predicts the local peak positions precisely and tracks the global peak under partial shading effectively. In addition to that, a skipping mechanism is integrated into it, which helps the MPPT to avoid scanning several sections of the I-V or P-V curve. Consequently, the global peak tracking gets accurate and faster than existing MPPT techniques. Several rigorous experiments are carried out in Matlab/Simulink to verify the behaviour of the MPPT. It is observed that under deep shading where the global peak resides on the left zone in voltage profile, tracking speed gets significantly faster. Furthermore, the proposed scheme is implemented in hardware through buck-boost converter in conjunction with dSpace DS1104 board to justify the applicability. Tracking results under several partial shading shows that the proposed method outperforms other MPPT techniques namely Modified Incremental Conductance (MIC), Ant colony optimization-P&O (ACO-P&O) and Cuckoo Search (CS) by a significant margin. Tracking speed is improved by 2 to 3 times depending on the shading pattern and efficiency is well ensured over 99% under all cases