As the global population grows, and urbanization becomes more prevalent, cities often struggle to provide convenient, secure, and sustainable lifestyles due to the lack of necessary smart technologies. Fortunately, the Internet of Things (IoT) has emerged as a solution to this challenge by connecting physical objects using electronics, sensors, software, and communication networks. This has transformed smart city infrastructures, introducing various technologies that enhance sustainability, productivity, and comfort for urban dwellers. By leveraging Artificial Intelligence (AI) to analyze the vast amount of IoT data available, new opportunities are emerging to design and manage futuristic smart cities. In this review article, we provide an overview of smart cities, defining their characteristics and exploring the architecture of IoT. A detailed analysis of various wireless communication technologies employed in smart city applications is presented, with extensive research conducted to determine the most appropriate communication technologies for specific use cases. The article also sheds light on different AI algorithms and their suitability for smart city applications. Furthermore, the integration of IoT and AI in smart city scenarios is discussed, emphasizing the potential contributions of 5G networks coupled with AI in advancing modern urban environments. This article contributes to the existing literature by highlighting the tremendous opportunities presented by integrating IoT and AI, paving the way for the development of smart cities that significantly enhance the quality of life for urban dwellers while promoting sustainability and productivity. By exploring the potential of IoT, AI, and their integration, this review article provides valuable insights into the future of smart cities, demonstrating how these technologies can positively impact urban environments and the well-being of their inhabitants.

We investigated the amount of time that large and small, male and female fiddler crabs Uca annulipes (H. Milne Edwards, 1837) spent on feeding, walking, standing, grooming, burrowing, inside burrows, fighting, and courtship waving. We video-recorded the activities of 45 males (22 small and 23 large), and 39 females (19 small and 20 large) each for 5 min, and calculated the percentage of time spent on each activity/crab. Our results showed that both sexes spent more time on feeding than on other activities. Males spent more time on building burrows, walking, and grooming than females, and females spent more time inside burrows than males. Smaller males spent more time on feeding, and less time on building burrows and on waving than larger ones. There were no relations between female body size and activities. Feeding rate/feeding claw was higher in males than in females, and crab body size was negatively associated with feeding rate/min. RÉSUMÉNous avons étudié le temps que passent les mâles et les femelles du crabe violoniste Uca annulipes (H. Milne Edwards, 1837) pour l'alimentation, la marche, le repos, la toilette, le creusement du terrier, le temps passé à l'intérieur du terrier, les combats et la parade. Nous avons enregistré en vidéo les activités de 45 mâles (22 petits and 23 grands), et 39 femelles (19 petites et 20 grandes) chacun pendant 5 min, et nous avons calculé le pourcentage de temps passé à chaque activité/crabe. Nos résultats ont montré que les deux sexes passent plus de temps pour se nourrir que pour toutes les autres activités. Les mâles passent plus de temps à bâtir des terriers, marcher et faire leur toilette que les femelles, et les femelles passent plus de temps à l'intérieur des terriers que les mâles. Les mâles plus petits passent plus de temps à s'alimenter et moins de temps à construire des terriers et à la parade nuptiale que les mâles plus grands. Il n'y a pas de relation entre la taille du corps de la femelle et ses activités. Le rapport taux d'alimentation/longueur de la pince servant à la prise de nourriture était plus élevé chez les mâles que chez les femelles, et la taille du corps du crabe était associé négativement au rapport taux d'alimentation/min.

Uca bengali Crane, 1975 females have two small feeding claws but males have one small feeding claw and another big claw used for waving and fights. On the basis of video recordings of feeding motions and duration, and morphometric measurements of body size (measured as carapace width) and feeding claw size (measured as dactyl length and width), differences in feeding rate per crab and per feeding claw, feeding duration, and feeding claw size between sexes were studied with the main aim to test male ability to compensate for the loss of one functional feeding claw. Additionally, feeding rate of males and females of small and large size classes was studied. Furthermore, correlations between feeding rate and body size, as well as feeding claw size and body size were investigated. Results showed that increased feeding rate per feeding claw coupled with a larger feeding claw allowed males to compensate for the loss of one feeding claw. Smaller males and females fed faster than larger ones. There was a negative correlation between feeding rate and carapace width. Feeding duration did not vary between males and females of comparable size. A positive correlation was observed between feeding claw size and carapace width. RÉSUMÉLes femelles de Uca bengali Crane, 1975, possèdent deux petites pinces servant à la nutrition (pinces alimentaires) mais les mâles ont une petite pince alimentaire et une autre, grosse, utilisée pour faire des signaux et pour les combats. À partir d'enregistrements vidéos des mouvements de nutrition et de leur durée, et de mesures morphométriques de la taille du corps (mesurée par la largeur de la carapace) et de la taille de la pince (longueur et largeur du dactyle), des différences du taux d'alimentation par crabe et par pince alimentaire, de la durée de l'alimentation, de la taille de la pince alimentaire dans les deux sexes ont été étudiées dans le but principal de tester la capacité du mâle à compenser la perte d'une pince alimentaire fonctionnelle. De plus, le taux d'alimentation des mâles et des femelles de classes de taille petites et grandes ont été étudiées. De plus, les corrélations entre le taux d'alimentation et la taille du corps ainsi que, entre la taille de la pince alimentaire et la taille

The alteration of signals of animals in response to changes in environmental factors is a common phenomenon. In male fiddler crabs, waving major claws towards females is energetically costly; thus, males need to adjust their waving in a way that increases the chance of potential mate attraction while reducing the waving cost. In this study, I examined how Austruca perplexa males adjusted their waving rate based on male-male competition (male numbers in a cluster [Austruca perplexa males make groups and wave synchronously towards females]), female body size, and the distances of the receiver females from the signaller males. Forty clusters were selected randomly; from each cluster, I randomly selected one male, video recorded his waving behaviour and calculated waving rate (waves/min). Body size (carapace width) and distances of receiver females were measured. To analyze the effects of competition, female size, and their distances on male waving rate through binary logistic regression analysis, all variables were divided into two categories (male waving rate: low and high, competition: low and high, female size: small and large, and female distances: short and long) based on a median split method. Afterwards a series of binary logistic regression models were built and the relative supports of various models were assessed based on the corrected Akaike information criterion. Results showed that competition, female body size and their distances affected the male waving rate in an additive manner, but their interactions did not show any effect. Further research can be conducted to investigate how breeding season and predation risk along with competition, female size and female distances affect the claw-waving display of male fiddler crabs.

We tested for the first time how Austruca bengali Crane, 1975 signaller males adjusted their waving rates based on receiver female body sizes and their distances. We video recorded the waving display of 46 males (9–12 mm carapace width) for 30 s, and counted their waving rate. Receiver females were categorised as small (8–10 mm carapace width) and large (>10 mm). Distances between males and females were categorised as short (⩽12 cm) and long (>12 cm) distances. Our results indicate that males are able to measure distances and female sizes, and adjust their waving display by actively reducing waving rate (1) towards small females, as usually small females have lower fecundity compared to large ones and (2) towards females at very close distance because at this point, the females would make their mating decision, and thus males start to lead/hit the females towards their burrow rather than waving vigorously.

This study investigates the burrow temperature of large-sized male and female Tubuca rosea (Tweedie, 1937) crabs as well as the soil temperature near their burrows during the day and night. Burrow and soil temperatures were measured using temperature sensors and burrow characteristics were recorded. Both sexes built I- and J-shaped burrows. Female burrows were longer and deeper than male burrows, since female burrows act as breeding burrows in this species. J-shaped burrows were longer and slightly deeper than I-shaped ones. During the day, the burrow temperature was lower than the soil temperature; however, during the night, the opposite result was observed. The burrow length/depth was negatively correlated with the burrow temperature during the day, but these correlations were positive during the night. This study shows that the burrow characteristics of T. rosea modulate the inside temperature of the burrows, maintaining a suitable temperature for the crabs.

We studied the effects of claw regeneration on male waving rate and burrow characteristics (i.e., important mate choice criteria) by examining the waving rates and burrow characteristics (diameter, total and horizontal lengths, depth, volume, maximum width, entry and burrow angles, and presence and location of chambers) of large-sized original-clawed males (OCMs) and regenerated-clawed males (RCMs) of Austruca perplexa (H. Milne Edwards, 1852). Female burrows were also examined. The results showed that female burrows were smaller than male burrows, with no chamber and, thus, female burrows are not used for breeding; however, 80% of RCM burrows, and 65% of OCM burrows, had chambers. Other characteristics were not different between RCM and OCM burrows, except for maximum width, which was larger in RCM burrows. The waving rates of OCMs and RCMs were not different. Our results indicate that claw regeneration do not have detrimental effects on male waving rate and burrow characteristics.

In Thailand, mangosteen (Garcinia mangostana) production is essential for domestic consumption and export. Mangosteen without scars on their surface is considered high-quality fruit. Scars reduce their market demand. The common cause of scars is thrips infestation. Humidity is an important climatic factor that affects the thrips populations. Lower humidity inside the mangosteen canopy increases the thrips numbers. Thus, increasing humidity can control the thrips population. This study developed a smart watering system to increase the humidity inside the mangosteen canopy in Nakhon Si Thammarat province, southern Thailand. This system provided water automatically and increased humidity inside the mangosteen canopy.