International Islamic University, Chittagong

In the age of the digital economy, technological advancements are reshaping labor markets, creating both new opportunities and challenges. However, the impact of digitalization, particularly the roles of artificial intelligence (AI) and technological innovation (TI), on employment remains insufficiently examined. This study examines the effect of the digital economy on employment in 36 OECD countries from 2005 to 2022, focusing on the moderating roles of AI and TI, using the Driscoll-Kraay Standard Errors (DKSE) model and various robustness tests. The findings show that: (1) the digital economy enhances employment, with a stronger effect at lower employment quantiles; (2) AI and TI strengthen the digital economy's impact, although AI's direct effect is negative, while innovation's effect is positive; (3) the digital economy increases employment through political, economic, and social globalization; (4) sectoral analysis reveals that the digital economy reduces jobs in agriculture while boosting those in the service sector, and has a positively insignificant effect on the industrial sector; and (5) heterogeneity analysis indicates that the digital economy's benefits are more pronounced in highly developed, industrialized, and less urbanized countries. The study emphasizes the need for tailored policies to maximize the benefits of digitalization, address the challenges posed by AI, and ensure sustainable and equitable labor market growth.

Chalcogenide perovskites have recently emerged as a promising family of functional materials owing to their tunable electronic structures, chemical stability, and potential in thermoelectric, optoelectronic, and protective-coating applications. In this work, we present a comprehensive first-principles investigation of the structural, mechanical, thermal, electronic and optical properties of the chalcogenide perovskites BaTaS3 and BaNbS3 using density functional theory (DFT). The optimized lattice parameters for BaTaS3 (a = 6.948 Å, c = 5.709 Å) and BaNbS3 (a = 6.932 Å, c = 5.749 Å) agree well with available literature. Both compounds crystallize in the orthorhombic phase and exhibit metallic electronic characteristics. The calculated elastic constants satisfy the Born stability criteria, confirming their mechanical stability, while moderate elastic anisotropy is observed from the directional dependence of Young’s modulus. The evaluated bulk, shear, and Young’s moduli reveal that BaNbS3 is mechanically stiffer than BaTaS3. The Debye temperatures were estimated to be 309.2 K (BaTaS3) and 330.8 K (BaNbS3), while the minimum lattice thermal conductivities were calculated as 2.7 and 2.88 W m⁻¹ K⁻¹, respectively. Optical analysis reveals high reflectivity (> 65

The fast proliferation of the Internet of Things (IoT) networks requires lightweight and yet powerful cryptographic tools to ensure secure communication within resource-limiting settings. This work presents a novel construction of the 8 × 8 S-box using the generator matrix of the [15, 11] linear block code. To test its applicability in practice, the S-box becomes a part of an IoT authentication system that combines PIN verification, a one-time password (OTP) as fail-and-save mechanism, and a post-quantum learning-with-errors (LWE) challenge-response protocol. Moreover, an artificial intelligence-based analysis tool is created to categorize and evaluate the cryptographic strength of the proposed S-box. Experimental findings prove outstanding performance: Naïve Bayes, Decision Tree, Random Forest, BERT, RoBERTa, and LLaMA demonstrate ideal accuracy, precision, recall, and F1-scores which further confirm the reliability, scalability, and reproducibility of the suggested evaluation framework. These findings confirm that the constructed S-box not only achieves strong cryptographic properties but also provides a validated, AI-assisted way of improving confidentiality and reliability in telecommunication systems based on the internet of things.

This study reports the synthesis of Dy3+, Sm3+ singly-doped and co-doped Ca2Y1-x-yDyxSmySbO6 phosphors via a high-temperature solid-state reaction method. Photoluminescence spectroscopy determined that the optimal doping concentration, sintering temperature and time are x = 0.03, 1300 degrees C, and 8 h for Ca2Y1-xDyxSbO6, which yields intense yellow emission centered at 576 nm (4F9/2 -> 6H13/2 transition) under 349 nm excitation. For Ca2Y1ySmySbO6, y = 0.025 and sintering at 1500 degrees C produces intense red emission centered at 601 nm (4G5/2 -> 6H7/2 transition) under 407 nm excitation. Co-doping both Dy3+ and Sm3+ into the Ca2YSbO6 host enabled tunable multi-colour luminescence under specific excitation wavelengths. However, temperature-dependent studies (300-500 K) revealed that the Ca2Y0.945Dy0.03Sm0.025SbO6 phosphors co-doped with their respective optimized concentration (x = 0.03 and y = 0.025) exhibits a degradation in both emission intensity and color purity against temperature, attributed to excessive total rare-earth ion doping concentration. Despite this thermal quenching, integrating the co-doped Ca2Y0.945Dy0.03Sm0.025SbO6 phosphor with a 365-nm LED chip successfully generated warm white light, demonstrating potential application in warm white-light-emitting diodes.

The magnetic, dielectric and photocatalytic properties of Fe and Ni co-doped Co3O4 nanoparticles (NPs) were studied in detail. XRD was done for the phase formation and structural analysis, which confirmed pure spinel phase of Co3O4 using Rietveld refinement. The average crystallite size was calculated using refinement data which showed an increase from 16 to 32 nm with co-doping due to increased crystal growth and defects. Surface morphology was studied by using TEM analysis which revealed non-spherical shaped NPs with dense agglomeration having average particles size of 120 nm for undoped and 137 nm for FN44 co-doped, respectively. The increase in average particle size with co-doping is associated with increased crystal growth caused by co-dopants. Magnetic measurements indicate the onset of ferromagnetism (FM) with co-doping which gets strengthen with increasing Fe doping and maximum magnetization was attained for FN62 sample (6