Archaeological excavation in an area of Lavrio (mining area from ancient times) has revealed ancient metallurgical installations which offer valuable information on this activity at those times. ...Within this context, a combined geophysical investigation was carried out in a place near Keratea City to find out whether there are additional installations apart from those that have already been revealed in the immediate area. More importantly, the objective was to locate the ancient tanks which provided water to the installations. Archaeological and geological information have helped in the design of the survey. EMI method measuring apparent conductivity was used to cover the whole area of investigation. Conductivity maps in various investigation depths have positioned the tanks and stacked first derivative maps in two directions (the two directions of the revealed walls) show covered walls. The EMI survey has indicated the position of three (3) ERT profiles made with the dipole–dipole array, which presented the ancient tanks with great detail in depth. GPR profiles for the detection of walls were noisy with the coarse material surface layer but the interrelation with ERT and EMI results confirmed the detected features.
•Integrated geophysical survey to detect buried ancient tanks for water and walls•The ancient installations for metallurgical processing in Greece•Stacked directional 1st derivatives of EM data to detect linear objects•Combined interpretation of EM-ERT, EM-GPR and ERT-GPR data-results
Breast cancer is the most common cancer in women, a leading cause of morbidity and mortality, and a significant health issue worldwide. According to the World Health Organization’s cancer awareness ...recommendations, mammographic screening should be regularly performed on middle-aged or older women to increase the chances of early cancer detection. Breast density is widely known to be related to the risk of cancer development. The American College of Radiology Breast Imaging Reporting and Data System categorizes mammography into four levels based on breast density, ranging from ACR-A (least dense) to ACR-D (most dense). Computer-aided diagnostic (CAD) systems can now detect suspicious regions in mammograms and identify abnormalities more quickly and accurately than human readers. However, their performance is still influenced by the tissue density level, which must be considered when designing such systems. In this paper, we propose a novel method that uses CycleGANs to transform suspicious regions of mammograms from ACR-B, -C, and -D levels to ACR-A level. This transformation aims to reduce the masking effect caused by thick tissue and separate cancerous regions from surrounding tissue. Our proposed system enhances the performance of conventional CNN-based classifiers significantly by focusing on regions of interest that would otherwise be misidentified due to fatty masking. Extensive testing on different types of mammograms (digital and scanned X-ray film) demonstrates the effectiveness of our system in identifying normal, benign, and malignant regions of interest.
Model experiments in the laboratory are used to find the optimal measuring and interpretation parameters that affect the quality of the results for the improved application of resistivity tomography ...between boreholes or between the surface and a tunnel. The experiments have shown that the detection ability of each crosshole electrode array is different and depends on the form of the sensitivity pattern. The bipole–bipole array, with current and potential pairs in different boreholes, has quite low signal and very good resolution of confined bodies in homogeneous half-spaces, but the resolution decreases as the half-space becomes more complex. The bipole–bipole array with the electrodes of each bipole in different boreholes produces a stronger signal, causing the models to be greatly influenced, even by the presence of small targets. However, the resolution quality is poor, mainly in the middle of the area between the boreholes. Pole–bipole array shows good resolution of the targets detection, but it is less accurate when conditions become noisier. The pole–tripole array has the best resolution, even when the environment becomes more complex or noisier, but the produced models have also many artifacts. The combined arrays' data inversion yields the greatest influence of the targets on resistivity models, usually with very good positioning or shape resolution, but with many more intense artifacts, since this method inevitably combines the advantages and disadvantages of each array. A new approach to improve the quality of resistivity models has been developed, based on a stacking technique, through the processing of different arrays' inverted models (“MOST” technique). The improvement of the MOST models' quality has been measured, comparing each final resistivity model with the corresponding real one, highlighting this way the efficiency of this technique, in contrary to the combined arrays' data inversion.
► Laboratory study of cross-hole ERT in well-known and controlled conditions. ► Sensitivity analysis of cross-hole electrode arrays. ► Qualitative and quantitative analysis of certain electrode arrays. ► Model stacking technique to improve the quality of resistivity models.
An Inequality with Medians Apostolopoulos, George; Gayen, Subhankar
The American mathematical monthly,
12/2019, Letnik:
126, Številka:
10
Journal Article
Circles Next after Incircles Apostolopoulos, George; Faynshteyn, Oleh
The American mathematical monthly,
01/2018, Letnik:
125, Številka:
1
Journal Article
Display omitted
This paper aims at clarifying, by means of an integrated experimental and theoretical approach, the properties of the interaction between interstitial nitrogen (N) and irradiation ...generated lattice defects in α-Fe. For this purpose, N-doped and pure Fe specimens were irradiated at low temperature by high energy protons. The evolution of radiation defects and their interaction with N was monitored by electrical resistivity measurements during post-irradiation annealing. In parallel, density functional theory (DFT) was employed to study the properties of N solutes, vacancies and their mutual interaction in the Fe matrix. The DFT results were confronted to the experiment via kinetic rate theory modelling, employed to quantitatively simulate the measured resistivity evolution. One of the most important results is the experimental validation of the theoretically predicted strong binding energy of vacancy-N complexes, which reconciles previous discrepancies. Furthermore, a quantitative interpretation is provided of how irradiation competes with nitride precipitation.
Recent years, manufacturing aims on increasing flexibility while maintaining productivity for satisfying emerging market needs for higher product customization. Human Robot Collaboration (HRC) is ...able to bring about this balance by combining the benefits of manual assembly and robotic automation. When introducing a hybrid concept, safety and human acceptance are of vital importance for achieving implementation. Fenceless coexistence may lead to discomfort of operators especially in cases where close Human Robot Interaction (HRI) occurs. This work aims at designing and implementing a natural Human-System and System-Human interaction framework that enables seamless interaction between operators and their “robot colleagues”. This natural interaction will strengthen hybrid implementation through increased: a) operator’s and system’s awareness, b) operator’s trust to the system, and through the decrease of: a) human errors and b) safety incidents. The overall architecture of the proposed system makes it scalable, flexible, and applicable in different collaborative scenarios by enabling the connectivity of multiple interfaces with customizable environments according to operator’s needs. The performance of the system is evaluated on a scenario originating from the automotive industry proving that an intuitive interaction framework can increase acceptance and performance of both robots and operators.
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