Unsupervised Content Based Image Retrieval by Combining Visual Features of an Image With A Threshold

Content-based image retrieval (CBIR) uses the visual features of an image such as color, shape and texture to represent and index the image. In a typical content based image retrieval system, a set of images that exhibit visual features similar to that of the query image are returned in response to a query. CLUE (CLUster based image rEtrieval) is a popular CBIR technique that retrieves images by clustering. In this paper, we propose a CBIR system that also retrieves images by clustering just like CLUE. But, the proposed system combines all the features (shape, color, and texture) with a threshold for the purpose. The combination of all the features provides a robust feature set for image retrieval. We evaluated the performance of the proposed system using images of varying size and resolution from image database and compared its performance with that of the other two existing CBIR systems namely UFM and CLUE. We have used four different resolutions of image. Experimentally, we find that the proposed system outperforms the other two existing systems in ecery resolution of imag

The impact of geopolitical risk on CO2 emissions inequality: Evidence from 38 developed and developing economies

This paper analyses the impact of geopolitical risk on carbon dioxide (CO 2) emissions inequality in the panel dataset of 38 developed and developing economies from 1990 to 2019. At this juncture, the empirical models control for the effects of globalisation, capital-labour ratio, and per capita income on CO 2 emissions inequality. The panel cointegration tests show a significant long-run relationship among the related variables in the empirical models. The panel data regression estimations indicate that geopolitical risk, capital-labour ratio, and per capita income increase CO 2 emissions inequality. However, globalisation negatively affects CO 2 emissions inequality in the panel dataset of 38 developed and developing countries. The pairwise panel heterogeneous causality test results align with these benchmark results and indicate no reverse causality issue. Potential policy implications are also discussed.</p

Carbon-Enhanced Metal-Poor star candidates from BP/RP Spectra in GaiaGaia DR3

Carbon-enhanced metal-poor (CEMP) stars comprise almost a third of stars with [Fe/H] < --2, although their origins are still poorly understood. It is highly likely that one sub-class (CEMP-$s$ stars) is tied to mass-transfer events in binary stars, while another sub-class (CEMP-no stars) are enriched by the nucleosynthetic yields of the first generations of stars. Previous studies of CEMP stars have primarily concentrated on the Galactic halo, but more recently they have also been detected in the thick disk and bulge components of the Milky Way. $Gaia$ DR3 has provided an unprecedented sample of over 200 million low-resolution ($R\approx$ 50) spectra from the BP and RP photometers. Training on the CEMP catalog from the SDSS/SEGUE database, we use XGBoost to identify the largest all-sky sample of CEMP candidate stars to date. In total, we find 58,872 CEMP star candidates, with an estimated contamination rate of 12%. When comparing to literature high-resolution catalogs, we positively identify 60-68% of the CEMP stars in the data, validating our results and indicating a high completeness rate. Our final catalog of CEMP candidates spans from the inner to outer Milky Way, with distances as close as $r \sim$ 0.8 kpc from the Galactic center, and as far as $r >$ 30 kpc. Future higher-resolution spectroscopic follow-up of these candidates will provide validations of their classification and enable investigations of the frequency of CEMP-$s$ and CEMP-no stars throughout the Galaxy, to further constrain the nature of their progenitors.Comment: 19 pages, 14 figures, accepted to MNRA

A Global Collaborative Effort to Enhance Design in a Mechanical Engineering Curriculum in Saudi Arabia

In 2008, King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia and the Massachusetts Institute of Technology (MIT) partnered together to develop project-based curricular material to be tested out in a new undergraduate course offering in KFUPM’s Department of Mechanical Engineering. This paper details some of the unique challenges to collaborating across countries and time zones, and the approaches the KFUPM-MIT team used to address these. These approaches have so far included the establishment of a shared vision for the project and the use of an array of technologies to facilitate distance communication. The paper concludes with a description of lessons learned that might be useful for future programs that plan to engage in international collaboration on design education.Jāmiʻat al-Malik Fahd lil-Batrūl wa-al-Maʻādi