The Department of Transport in the United Kingdom recorded 25,080 motor vehicle fatalities in 2019. This situation stresses the need for an intelligent transport system (ITS) that improves road safety and security by avoiding human errors with the use of autonomous vehicles (AVs). Therefore, this survey discusses the current development of two main components of an ITS: (1) gathering of AVs surrounding data using sensors; and (2) enabling vehicular communication technologies. First, the paper discusses various sensors and their role in AVs. Then, various communication technologies for AVs to facilitate vehicle to everything (V2X) communication are discussed. Based on the transmission range, these technologies are grouped into three main categories: long-range, medium-range and short-range. The short-range group presents the development of Bluetooth, ZigBee and ultra-wide band communication for AVs. The medium-range examines the properties of dedicated short-range communications (DSRC). Finally, the long-range group presents the cellular-vehicle to everything (C-V2X) and 5G-new radio (5G-NR). An important characteristic which differentiates each category and its suitable application is latency. This research presents a comprehensive study of AV technologies and identifies the main advantages, disadvantages, and challenges.

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A morphohistological study was carried out on the pineal organ in 15 species of teleosts belonging to 12 different families. In spite of a general similarity in pineal structure in different species, there is evident a systematic diversity. The majority of species possess saccular pineal organs containing photoreceptors as prominent parenchymal components. The close anatomical relationship of the pineal organs with the relatively thin cranial roof further supports the photosensory nature of this organ in most species. However, in certain species, particularly Corydoras aneus, apparent paucity of sensory cell outer segments, parenchymal proliferation, epithelial compactness and rich vascularization suggest specializations for a predominantly nonsensory and possibly secretory function. On the other hand, the preponderance of sensory cells in the pineal organ of Symphysodon aequifasciatus and Gyrinocheilus aymoneri indicates exceptional adaptations for a predominantly photosensory role. The results are discussed in the light of existing electron microscopic and biochemical investigations which support a secretory function of fish pineal. The need for proper selection of species for future research on pineal function is emphasized.There is also evident a close anatomical relationship between the pineal organ, the dorsal sac and the third ventricle in various species. The possibility of intramural functional relationship of the pineal with these structures and the brain is suggested.The presence of intrapineal neurones and an afferent (pinealofugal) innervation in majority of species is described. The tractus pinealis enters the posterior commissure area. In rainbow trout, Salmo gairdneri, some branches, right and left, leave the posterior commissure and could be seen to move toward the habenular ganglia. Their destination remains unclear. In jack smelt, Atherinopsis californiensis, a major bundle of tract fibres follows the ventral aspect of the posterior commissure reaching what may be nuclei dorsomedialis-dorsolateralis. The possibility of direct connections with the fasciculus retroflexus is suggested. No evidence could be provided supporting existence of an efferent (pinealopetal) innervation of parenchymal cells in the pineal of species studied. It is pointed out that clarification of this aspect in future is important for a proper understanding of metabolic aspects of pineal organs in fishes.The functional status of pineal organ in fishes has been a subject of intensive research and review, yet little understanding of its physiology has so far been achieved. There is general agreement that in fishes it is photosensory in function (reviews by Tilney and Warren, '19; Gladstone and Wakeley, '40; Kelly, '62; U. Holmgren, '59, '65; Van De Kamer, '65 In spite of the above information our knowledge nf comparative aspects of pineal structure and innervation is still limited and consequently generalizations concerning pineal physiology may not be necessarily valid. The present report on the morphohistology of t...

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Abstract-The Internet of Things (IoT) has been considered as an emerging research area where the 6LoWPAN (IPv6 over Low-Power Wireless Personal Area Network) protocol stack is considered as one of the most important protocol suite for the IoT. Recently, the Internet Engineering Task Force has developed a set of IPv6 based protocols to alleviate the challenges of connecting resource limited (i.e. power supply, processing and memory) sensor nodes to the Internet. In 6LoWPAN networks, heavy network traffic causes congestion which significantly degrades network performance and effects the quality of service (QoS) aspects e.g. throughput, end-to-end delay and energy consumption. In this paper, we formulate the congestion problem as a noncooperative game framework where the nodes (players) behave uncooperatively and demand high data rate in a selfish way. Then, the existence and uniqueness of Nash equilibrium is proved and the optimal game solution is computed by using Lagrange multipliers and KKT conditions. Based on this framework, we propose a novel and simple congestion control mechanism called game theory based congestion control framework (GTCCF) specially tailored for IEEE 802.15.4, 6LoWPAN networks. GTCCF is aware of node priorities and application priorities to support the IoT application requirements. The proposed framework has been tested and evaluated through two different scenarios by using Contiki OS and compared with comparative algorithms. Simulation results show that GTCCF improves performance in the presence of congestion by an overall average of 30.45%, 39.77%, 26.37%, 91.37% and 13.42% in terms of throughput, end-to-end delay, energy consumption, number of lost packets and weighted fairness index respectively as compared to DCCC6 algorithm.