A Wireless Sensor Network ( Wsn )

More specifically, a sensor is "a device that responds to phenomena, such as light, pressure, or heat, and generates a signal that can be measured or interpreted" [16]. The sensor network community often defines a sensor node as a wireless device which is small, capable of responding to one or several stimuli, processing the data and transmitting the information over a short distance using a radio link. Sensor nodes contain electronic circuits for minimizing power consumption [17]. Sensors are for measuring sound, light and temperature that is typically thought. However, sensors can measure other variables, such as vibrations or electromagnetic fields [18]. Sensor transmits values wirelessly to one or several BSs

Ju young Kim et.al (2012) presented in their paper “A Review of the Vulnerabilities and Attacks for Wireless Sensor Networks” about the investigation of the distinctive vulnerabilities, threats and attacks for Wireless Sensor Networks. Viable administration of the

Nowadays, Wireless sensor networks (WSNs) are getting more and more involved in our society, researchers and manufacture. As the use of WSNs increases the more challenges rise to make them immune and life longer. Therefore, both fields industry and academia invest money to improve the capability of the security integrity, confidentiality, and authentication. Since WSNs are distributed in unfrequented and abandoned venues, the physical security is unconcerned or less concern. The most concern is the lifetime of Wireless sensor networks, sensors have limited source of power. Thus, economizing energy will keep sensors live longer, the less power means more efficiency. Moreover, secure data is important as well, since no one attends where sensors are located, it is easy to manipulate data or steal it. Cryptography provides high security to WSNs, using algorithms to encrypt and decrypt the sent data is

The impossible measurements in typical ways have currently become attainable using the wireless technology. Wireless sensors are used in most of the in real time applications for collecting physical information. Wireless sensors are spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. and to cooperatively pass their data through the network to a main location. They are self-configured sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location or sink where the data can be observed and analyzed. A sink or base station acts like an interface between users and the network. The main objective of this paper is to introduce air pollution detection using internet of things and to report the status of the air quality whenever needed. This system is low

In [76], Le et al. designed an environment learning-based phenomenon monitoring system in which the sensor nodes can move to the optimal positions which is selected based on the information that iteratively learned about the environment. Because nodes’ movements consume a large portion of the constrained energy in sensor nodes which will further shorten the lifetime of the WSN. Consequently, the question, “how to minimize the movements of mobile nodes while achieving desired coverage and connectivity in WSNs”, needs to be solved. In [77], authors

Wireless sensor networks consists of large number of sensors which are distributed densely and partially. There are numerous number of small sensor nodes which are self-restrained which consists of sensors which performs according to the environmental conditions.

Due to limited and non-rechargeable energy provision, the energy resource of sensor networks should be managed wisely to extend the lifetime of sensors. Sensor networks have recently emerged as a platform for several important surveillance and control applications .Each sensor has an onboard radio that can be used to send the collected data to interested parties. One of the advantages of wireless sensors networks (WSNs) is their ability to operate unattended in harsh environments in which contemporary human-in-the-loop monitoring schemes are risky, inefficient and sometimes infeasible. Therefore, sensors are expected to be deployed randomly in the area of interest by a relatively uncontrolled means, e.g. dropped by a helicopter, and to collectively form a network in an ad-hoc manner. In order to achieve high energy efficiency and increase the network scalability, sensor nodes can be organized into clusters. Data collected from sensors are sent to the cluster head first, and then forwarded to the base station. Network lifetime can be defined as the time elapsed until the first node (or the last node) in the network depletes its energy (dies).

With the recent technological advancements of smaller sensor devices enabling ubiquitous sensing capabilities and driven by the adoption of global standard technologies, Wireless Sensor networks (WSN) are evolving as one of the most significant technologies of 21st century (Ruiz-Garcia, Lunadei, Barreiro, & Robla, 2009). Though wired networks provide more stable and reliable communication, sensor networks with dense wireless networks of small, low cost sensors collecting and disseminating environment data has facilitated monitoring and controlling of physical environments from remote locations with better accuracy. Moreover, with the unique characteristics of flexibility, energy efficiency, distributed intelligence, low cost and most importantly with very good monitoring capabilities Wireless sensor networks serve wide range of applications in various fields such as remote environmental monitoring, home security, industry applications, military purposes such as target tracking along with preparing a ubiquitous computing environment (Ruiz-Garcia et al., 2009).

Multiple autonomous, tiny, low-cost and low-power sensor nodes comprise a wireless sensors network (WSN). The sensors nodes are equipped with various types of sensors such as thermal , acoustic, chemical, pressure, weather and optical sensors which gather information from various nodes and collaborate to forward sensed data to base stations for further processing. WSNs designers have to address common issues related to data aggregation, data reliability,

Wireless sensor networks ensure a wide range of applications [1], starting fromsecurity surveillance in military and battlefields, monitoring previously unobservedenvironmental phenomena, smart homes and offices, improved healthcare, industrialdiagnosis, and many more.Main of the issues in wireless sensor network is coverage and communication problem which directly reflect on connectivity between different nodes. The coverage problem is determined to how well the sensing field is monitored or tracked by sensors. In this paper, the entire existing problem is discussed and focused. We also classify the coverage problem into three categories: area coverage, target coverage, and barrier coverage.

With the recent technological advancements in smaller sensor devices with ubiquitous sensing and monitoring capabilities, Wireless Sensor Networks (WSN) are evolving as one of the most significant technologies of 21st century (Ruiz-Garcia, Lunadei, Barreiro, & Robla, 2009). Though wired networks provide more stable and reliable communication, wireless networking does provide more advantages with connectivity without being tethered. WSN with dense wireless networks of small, low cost sensors for collecting and disseminating environment data has facilitated connecting, monitoring and controlling of physical environments and environmental conditions such as temperature, humidity, pressure from remote locations with better accuracy which are not possible with wired networks (Potnis & Rajeshwari, 2015). Moreover, with the unique characteristics of flexibility, energy efficiency, distributed intelligence, low cost and most importantly with very good sensing and monitoring capabilities, WSNs are serving wide range of applications in various fields including remote environmental monitoring, home security, industry applications, military purposes such as target tracking by preparing and providing a ubiquitous computing environment (Ruiz-Garcia et al., 2009).

Wireless Sensor Networks (WSN) consists of a collection of nodes which are deployed randomly in a hostile environment. It has a fixed infrastructure and self-organized in to an arbitrary topology. Though there are advancements in technology, security in WSN is a principal concern. As the deployed sensors are in an open environment, the intrusion of attacks is very much higher. Also the WSN has broadcast nature of communication; they are easily affected by the attacks. Commonly prevailing attacks are Denial of Service (DoS) attacks, spoofing attack, selective forwarding attack, sinkhole attack, sybil attack, wormhole attack, black hole attack, grayhole attack, HELLO flood attack, etc. However we observe that Denial of Service attack is a

Wireless Sensor Networks (WSN) consists of large number of sensor nodes distributed across a geographical area in highly dense manner. These nodes are of low cost and use less energy to perform various functions. These sensors have the ability to communicate with each other and route the data to next node or back to the Base Station (BS). Sensor nodes in a sensor network communicate with other nodes and collect the information.

In the following parts of this section, we will firstly summarize the related work on analyzing the relationship between the sensing range Rs and communication range Rc. Then, we demonstrate the research efforts on finding critical conditions for achieving connectivity and coverage. Finally, we survey the approaches on connectivity and coverage in WSNs.

A NOVEL APPROACH TO ENHANCE THE LIFETIME AND THROUGHPUT OF WIRELESS SENSOR NETWORK USING ACTOR NODES.