Fine-grained Classification of Solder Joints with {\alpha}-skew Jensen-Shannon Divergence

Solder joint inspection (SJI) is a critical process in the production of printed circuit boards (PCB). Detection of solder errors during SJI is quite challenging as the solder joints have very small sizes and can take various shapes. In this study, we first show that solders have low feature diversity, and that the SJI can be carried out as a fine-grained image classification task which focuses on hard-to-distinguish object classes. To improve the fine-grained classification accuracy, penalizing confident model predictions by maximizing entropy was found useful in the literature. Inline with this information, we propose using the {\alpha}-skew Jensen-Shannon divergence ({\alpha}-JS) for penalizing the confidence in model predictions. We compare the {\alpha}-JS regularization with both existing entropyregularization based methods and the methods based on attention mechanism, segmentation techniques, transformer models, and specific loss functions for fine-grained image classification tasks. We show that the proposed approach achieves the highest F1-score and competitive accuracy for different models in the finegrained solder joint classification task. Finally, we visualize the activation maps and show that with entropy-regularization, more precise class-discriminative regions are localized, which are also more resilient to noise. Code will be made available here upon acceptance.Comment: Submitted to IEEE Transactions on Components, Packaging and Manufacturing Technolog

Perfect Metamaterial absorber based energy harvesting application in ISM Band

An electromagnetic (EM) energy harvesting application based on metamaterial absorber (MA) is introduced and discussed in this paper. This application is operating at ISM band (2.40 GHz) which is especially chosen due to its wide usage area. Square ring resonator (SRR) which has two gaps and resistors across the gaps on it is used. Chips resistors are used to deliver power to any active component. Transmission and reflection characteristics of metamaterial absorber (MA) for energy harvesting application are investigated. 83.6% efficient for energy harvesting application is realized in this study

Perfect Metamaterial absorber based energy harvesting application in ISM Band

An electromagnetic (EM) energy harvesting application based on metamaterial absorber (MA) is introduced and discussed in this paper. This application is operating at ISM band (2.40 GHz) which is especially chosen due to its wide usage area. Square ring resonator (SRR) which has two gaps and resistors across the gaps on it is used. Chips resistors are used to deliver power to any active component. Transmission and reflection characteristics of metamaterial absorber (MA) for energy harvesting application are investigated. 83.6% efficient for energy harvesting application is realized in this study

A Low Cost Shading Analyzer and Site Evaluator Design to Determine Solar Power System Installation Area

Shading analyzer systems are necessary for selecting the most suitable installation site to sustain enough solar power. Afterwards, changes in solar data throughout the year must be evaluated along with the identification of obstructions surrounding the installation site in order to analyze shading effects on productivity of the solar power system. In this study, the shading analysis tools are introduced briefly, and a new and different device is developed and explained to analyze shading effect of the environmental obstruction on the site on which the solar power system will be established. Thus, exposure duration of the PV panels to the sunlight can be measured effectively. The device is explained with an application on the installation area selected as a pilot site, Denizli, in Turkey

Review of the Performance of Residential PV systems in Belgium

The main objective of this paper is to review the state of the art of residential PV systems in Belgium by the analysis of the operational data of 993 installations. For that, three main questions are posed: how much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? This work brings answers to these questions. A middling commercial PV system, optimally oriented, produces a mean annual energy of 892 kWh/kWp. As a whole, the orientation of PV generators causes energy productions to be some 6% inferior to optimally oriented PV systems. The mean performance ratio is 78% and the mean performance index is 85%. That is to say, the energy produced by a typical PV system in Belgium is 15% inferior to the energy produced by a very high quality PV system. Finally, on average, the real power of the PV modules falls 5% below its corresponding nominal power announced on the manufacturer's datasheet. Differences between real and nominal power of up to 16% have been detected

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Design and analysis of perfect metamaterial absorber in GHz and THz frequencies

The new perfect metamaterial absorber (MA) based on square resonator with gap configuration is numerically (for GHz and THz frequency regime) and experimentally (for GHz frequency regime) presented and investigated. The proposed MA has a simple configuration which introduces flexibility to adjust its metamaterial properties and easily rescale the structure for other frequency regimes. In addition, polarization and incident angle independencies of the proposed model are analyzed for the THz frequency regime. The suggested structure could achieve very high absorption at wide angles of polarization and incident angles for both transverse electric and transverse magnetic waves. At resonance frequencies, absorption results are realized around 99.99% at 5.48GHz and 99.92% at 0.865THz for their respective frequency regimes. Besides numerical results in GHz and THz frequencies, experimental results are also obtained for GHz frequency regime. The proposed MA and its variations enable myriad potential applications in areas such as defense systems, communication, stealth technologies, and so on

Metamaterial characterization by applying different boundary conditions on triangular split ring resonator type metamaterials

This study aims to demonstrate the effects of the different boundary conditions on triangular split ring resonator (TSRR)-shaped metamaterials in X band frequency regime. Three different TSSR-shaped metamaterials are designed and simulated in a certain frequency range. TSSR-shaped metamaterials are utilized to show that the use of different boundary conditions may result in completely different electromagnetic responses. Characterization is explained by applying 5 different boundary conditions. To verify simulation results, an experimental study is realized for the unit cell boundary condition. Both experimental and simulation results are complying with each other. For further investigation, electrical energy density and surface current distributions are simulated and discussed

Ultra-Sensitive Dual-Band Metamaterial Absorber Based on Symmetric Resonators

Ultra sensitive metamaterial-based absorber (MA) which acts as a strong dual-band resonator is designed and constructed. The proposed model is based on symmetric ring resonator with gaps and octa-star strip (OSS) which allows maximization in the absorption at the resonances. Two maxima in the absorption are experimentally and numerically obtained with good agreement. The numerical studies verify that the dual-band MA can provide perfect absorption at wide angles of polarization and incidence waves. The proposed model can easily be used in many potential application areas such as security systems, sensors, medical imaging technology, and so on