There is no escaping fact that a huge amount of unexploited resources lies underwater which covers almost 70% of the Earth. Yet, the aquatic world has mainly been unaffected by the recent advances in the area of wireless sensor networks (WSNs) and their pervasive penetration in modern day research and industrial development. The current pace of research in the area of underwater sensor networks (UWSNs) is slow due to the difficulties arising in transferring the state-of-the-art WSNs to their underwater equivalent. Maximum underwater deployments rely on acoustics for enabling communication combined with special sensors having the capacity to take on harsh environment of the oceans. However, sensing and subsequent transmission tend to vary as per different subsea environments; for example, deep sea exploration requires altogether a different approach for communication as compared to shallow water communication. This paper particularly focuses on comprehensively gathering most recent developments in UWSN applications and their deployments. We have classified the underwater applications into five main classes, namely, monitoring, disaster, military, navigation, and sports, to cover the large spectrum of UWSN. The applications are further divided into relevant subclasses. We have also shown the challenges and opportunities faced by recent deployments of UWSN.

https://journals.sagepub.com/doi/pdf/10.1155/2015/896832

Underwater sensor network applications: a comprehensive survey

Electronic-nose (e-nose) instruments, derived from numerous types of aroma-sensor technologies, have been developed for a diversity of applications in the broad fields of agriculture and forestry. Recent advances in e-nose technologies within the plant sciences, including improvements in gas-sensor designs, innovations in data analysis and pattern-recognition algorithms, and progress in material science and systems integration methods, have led to significant benefits to both industries. Electronic noses have been used in a variety of commercial agricultural-related industries, including the agricultural sectors of agronomy, biochemical processing, botany, cell culture, plant cultivar selections, environmental monitoring, horticulture, pesticide detection, plant physiology and pathology. Applications in forestry include uses in chemotaxonomy, log tracking, wood and paper processing, forest management, forest health protection, and waste management. These aroma-detection applications have improved plant-based product attributes, quality, uniformity, and consistency in ways that have increased the efficiency and effectiveness of production and manufacturing processes. This paper provides a comprehensive review and summary of a broad range of electronic-nose technologies and applications, developed specifically for the agriculture and forestry industries over the past thirty years, which have offered solutions that have greatly improved worldwide agricultural and agroforestry production systems.

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Diverse Applications of Electronic-Nose Technologies in Agriculture and Forestry

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

Underwater Optical Wireless Communications, Networking, and Localization: A Survey

Advances in wireless communication are forging new possibilities for sensors. New sensors are equipping major systems around us with unparalleled intelligence as in the case of smart grids, smart homes, and driverless vehicles. Considering the current developments in the field of sensor networks, one feels that it has reached an interesting stage, where the role of the sensors becoming crucial in numerous applications. This all speaks volumes of the fact that sensors are going to be at the front and center of most of future technologies, needless to say the Internet of Things. Considering their vital role from futuristic perspective this survey reports variety of sensors along with their characteristics and applications, which impact human life and well-being. In addition, this survey considers recent prototypes, leading sensor manufacturers as well as major projects that have made use of sensors since the last decade. Moreover, significance of this effort is that integration possibilities of sensors with other networks and major technologies are discussed, while possible challenges and key benefits are highlighted. This research effort focuses the latest developments in the area of sensors and sensor networks as research gears up to meet the challenges of the emerging technologies and their applications particularly those that emphasize smart sensors.

Wireless Sensor’s Civil Applications, Prototypes, and Future Integration Possibilities: A Review

A systematic literature review on prototyping with Arduino: Applications, challenges, advantages, and limitations

There is an increasing need for environmental measurement systems to further science and thereby lead to improved policies for sustainable management. Marine environments are particularly hostile and extremely difficult for deploying sensitive measurement systems. As a consequence the need for data is greatest in marine environments, particularly in the developing economies/regions. Expense is typically the most significant limiting factor in the number of measurement systems that can be deployed, although technical complexity and the consequent high level of technical skill required for deployment and servicing runs a close second. This paper describes the Smart

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SEMAT — The Next Generation of Inexpensive Marine Environmental Monitoring and Measurement Systems

The increasing need to manage complex environmental problems demands a new approach and new technologies 
to provide the information required at a spatial and temporal resolution appropriate to the scales at which the 
biological processes occur. In particular sensor networks, now quite popular on land, still poses many difficult 
problems in underwater environments. In this context, it is necessary to develop an autonomous monitoring 
system that can be remotely interrogated and directed to address unforeseen or expected changes in such environmental 
conditions. This system, at the highest level, aims to provide a framework for combining observations 
from a wide range of different in-situ sensors and remote sensing instruments, with a long-term plan for how 
the network of sensing modalities will continue to evolve in terms of sensing modality, geographic location, and 
spatial and temporal density. The advances in sensor technology and digital electronics have made it possible 
to produce large amount of small tag-like sensors which integrate sensing, processing, and communication 
capabilities together and form an autonomous entity. To successfully use this kind of systems in under water 
environments, it becomes necessary to optimize the network lifetime and face the relative hindrances that such 
a field imposes, especially in terms of underwater information exchange.

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Advanced monitoring systems for biological applications in marine environments

The sustainable management of coastal and offshore ecosystems, such as coral reef environments, requires the collection of accurate data across various temporal and spatial scales. Accordingly, monitoring systems are seen as central tools for ecosystem-based environmental management, helping on one hand to accurately describe the water column and substrate biophysical properties, and on the other hand to correctly steer sustainability policies by providing timely and useful information to decision-makers. A robust and intelligent sensor network that can adjust and be adapted to different and changing environmental or management demands would revolutionize our capacity to wove accurately model, predict, and manage human impacts on our coastal, marine, and other environments. Underwater measurements are greatly influenced by environmental conditions; especially in shallow waters. Temperature, salinity, turbidity, oxygen, pH and many other parameters still need optimization due to the difficulty in performing the process in situ in such an environment. Notably however, modern developments in wireless network technology and miniaturization now make it possible to realistically monitor the aquatic environment in situ using smart devices that are completely autonomous. However, to successfully use these kinds of systems in under water environments it is necessary from the outset to define the specific requirements and relative hindrances that such a field imposes; especially in terms of underwater information exchange. The aim of this paper is to examine these issues and to propose strategies for the cost effective and scientifically robust integration of remote sensor network technologies for the monitoring and management of critical marine environments such as coral reefs.

Tony Chiffings

Papers

SEMAT — The Next Generation of Inexpensive Marine Environmental Monitoring and Measurement Systems

Advanced monitoring systems for biological applications in marine environments

Smart integrated sensor networks for the marine environment