Classification of Routing Algorithms in Volatile Environment of Underwater Wireless Sensor Networks

The planet earth is basically a planet of water with less than 30% land mass available for humans to live on. However, the areas covered with water are important to mankind for the various resources which have been proven to be valuable. Such resources are gas, oil, marine products which can be used as food, and other minerals. In view of the vast area in which these resources can be found, a network of sensors is necessary so that they can be explored. However, sensor networks may not be helpful in the exploration of these resources if they do not have a sufficiently good routing mechanism. Over the past few decades, several methods for routing have been suggested to address the volatile environment in underwater communications. These continue researches; have enhanced the performance along with time. Meanwhile, there are still challenges to deal with for a better and efficient routing of data packets. Large end-to-end delays, high error channel rates, limited bandwidth, and the consumption of energy in sensor network are some such challenges. A comprehensive survey of the various routing methods for the partially connected underwater communication environment are presented in this paper

Localization Algorithms of Underwater Wireless Sensor Networks: A Survey

In Underwater Wireless Sensor Networks (UWSNs), localization is one of most important technologies since it plays a critical role in many applications. Motivated by widespread adoption of localization, in this paper, we present a comprehensive survey of localization algorithms. First, we classify localization algorithms into three categories based on sensor nodes’ mobility: stationary localization algorithms, mobile localization algorithms and hybrid localization algorithms. Moreover, we compare the localization algorithms in detail and analyze future research directions of localization algorithms in UWSNs

EFFICIENT DYNAMIC ADDRESSING BASED ROUTING FOR UNDERWATER WIRELESS SENSOR NETWORKS

This thesis presents a study about the problem of data gathering in the inhospitable underwater environment. Besides long propagation delays and high error probability, continuous node movement also makes it difficult to manage the routing information during the process of data forwarding. In order to overcome the problem of large propagation delays and unreliable link quality, many algorithms have been proposed and some of them provide good solutions for these issues, yet continuous node movements still need attention. Considering the node mobility as a challenging task, a distributed routing scheme called Hop-by-Hop Dynamic Addressing Based (H2- DAB) routing protocol is proposed where every node in the network will be assigned a routable address quickly and efficiently without any explicit configuration or any dimensional location information. According to our best knowledge, H2-DAB is first addressing based routing approach for underwater wireless sensor networks (UWSNs) and not only has it helped to choose the routing path faster but also efficiently enables a recovery procedure in case of smooth forwarding failure. The proposed scheme provides an option where nodes is able to communicate without any centralized infrastructure, and a mechanism furthermore is available where nodes can come and leave the network without having any serious effect on the rest of the network. Moreover, another serious issue in UWSNs is that acoustic links are subject to high transmission power with high channel impairments that result in higher error rates and temporary path losses, which accordingly restrict the efficiency of these networks. The limited resources have made it difficult to design a protocol which is capable of maximizing the reliability of these networks. For this purpose, a Two-Hop Acknowledgement (2H-ACK) reliability model where two copies of the same data packet are maintained in the network without extra burden on the available resources is proposed. Simulation results show that H2-DAB can easily manage during the quick routing changes where node movements are very frequent yet it requires little or no overhead to efficiently complete its tasks

Ambient Data Collection with Wireless Sensor Networks

One of the most important applications for wireless sensor networks (WSNs) is Data Collection, where sensing data arecollected at sensor nodes and forwarded to a central base station for further processing. Since using battery powers and wirelesscommunications, sensor nodes can be very small and easily attached at specified locations without disturbing surroundingenvironments. This makes WSN a competitive approach for data collection comparing with its wired counterpart. In this paper,we review recent advances in this research area. We first highlight the special features of data collection WSNs, by comparingwith wired data collection network and other WSN applications. With these features in mind, we then discuss issues and priorsolutions on the data gathering protocol design. Our discussion also covers different approaches for message dissemination, whichis a critical component for network control and management and greatly affects the overall performance of a data collectionWSNsystem

Elderly Housing Design in Charlton, Massachusetts

The design of an elderly housing facility provided experience in construction and project management characteristics that included architectural layout development, code analysis, cost estimation, and scheduling. A preliminary building plan was established by investigating spatial layouts and numerical data. The code analysis was used to verify preliminary layouts and alter certain aspects in order for the facility to be code compliant. Technical specifications were prepared to describe assemblies of construction in the building process. Using the specifications, a cost estimate was completed to provide approximate cost of the building process and all its components. The scheduling of the project allowed for approximate determination of substantial completion

A Reverse Localization Scheme for Underwater Acoustic Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time

Service Experience & Expectations of Saudi Arabia Domestic Tourists in the Lodging Sector

The Saudi’s 2030 vision has recognized the vital role of religious tourism in the diversification of the kingdom’s economy in addition to the reliance on gas and oil revenue. Currently, religious tourism contributes at least 3% of the Saudi’s GDP. The government plans to double the revenue from the religious tourism by doubling the accommodation capacity for both the Hajj and Umrah visitors. The increasing number of international and luxurious hotels in Makkah and other major cities reflect a rising of the hotel industry in Saudi Arabia. Research has documented the importance role of service quality in influencing organizational outcomes such as increasing sales profits, promoting customer loyalty, improving customer relations, enhancing customer satisfaction, and performance superiority. It\u27s important for hotels in Saudi Arabia to provide quality service to ensure sustainable success in the competitive global market. The purpose of this study is to evaluate the service quality of Saudian hotels from the aspects of tangibility, reliability, responsiveness, assurance, empathy to determine if there is a service quality gap between the hotels in Saudi Arabia and outside the Middle East. This study adopted a qualitative approach by conducting in-depth interviews among 24 experienced hotel guests. The findings of the study can serve as reference for hotel companies to improve their service quality and to elevate the image of hotels in Saudi Arabia

Fifteen-foot diameter modular space station Kennedy Space Center launch site support definition (space station program Phase B extension definition)

This document defines the facilities, equipment, and operational plans required to support the MSS Program at KSC. Included is an analysis of KSC operations, a definition of flow plans, facility utilization and modifications, test plans and concepts, activation, and tradeoff studies. Existing GSE and facilities that have a potential utilization are identified, and new items are defined where possible. The study concludes that the existing facilities are suitable for use in the space station program without major modification from the Saturn-Apollo configuration

A key distribution scheme for mobile underwater wireless sensor networks

Wireless Sensor Networks consist of small battery-limited devices called sensor nodes. They are used for collecting data from surrounding environment and relay them via wireless communication. One of the recent application areas is underwater sensing. Communication in Underwater Wireless Sensor Networks (UWSN) is different from airborne communication. Radio frequencies cannot be used for UWSN. Instead acoustic waves, which cause extra challenges, are used in UWSN. When UWSNs are deployed in hostile environment, nodes can be captured by an adversary. In order to secure UWSNs, firstly key distribution problem must be addressed. Moreover, UWSNs are inherently mobile since the nodes may be drifted in the sea. In this thesis, we propose a key distribution model which is applied for two group mobility models, namely (i) nomadic mobility model and (ii) meandering current mobility model. Our nomadic mobility based key distribution scheme works in three dimensions. However, this scheme is suitable only for small coastal areas. On the other hand, our meandering mobility based key distribution model is a two dimensional one and spans several kilometers in the open sea. In both schemes, a hierarchical structure is used. Secure and resilient group communication is handled via well-known Blom's key distribution scheme. We analyzed the performance of the proposed schemes using simulations. Our results show that secure connectivity of both schemes is generally high. Of course, mobility causes some temporary decreases in the connectivity, but our schemes help to heal the connectivity performance in time. Moreover, our schemes show good resiliency performance such that capture of some nodes by an adversary only causes very small amount of links between uncaptured nodes to be compromised