إن البيوت المحمية ذات أهمية كبيرة في المجال الزراعي فهي تؤمن البيئة المناسبة والهامة لنمو وإنتاج النباتات المختلفة بغض النظر عن الظروف البيئية المحيطة, إن المراقبة والتحكم في هذه البيوت يعتبر أمر ضروري وهام من أجل توفير البيئة المطلوبة والحصول على أف
ضل إنتاج, لذلك فان الغاية من هذا المشروع هي دراسة مراقبة هذه البيوت والتحكم بها باستخدام شبكات الحساسات اللاسلكية والتي تعتبر من الطرق الحديثة والبسيطة لما توفره من دقة في العمل وجهد قليل وبالتالي إنتاج أفضل وستكون الدراسة من أجل عدة تشكيلات وتصاميم لنموذج البيت المحمي وإجراء المحاكاة باستخدام برنامج ال OPNET لتحديد أي من التصاميم هو الأفضل للحصول على عمل أفضل على أرض الواقع.
The reducing of energy consumption for various nodes in wireless sensor networks
plays an important and essential role in the prolonging of the life of these networks. In
order not to be the energy consumption in some node is very high and in other
s is less or
very low, the choice of distribution algorithms of the nodes role, as a router node or
terminal nodes, and switching between them, plays an important role in prolonging the
lifetime of wireless sensor networks.
This paper presents an algorithm for the distribution of WSN nodes roles, including
allowing the applying of many tree patterns to a single network. This offers the potential to
alter the network nodes roles centrally by coordinator and switching between these tree
patterns whenever the need arises according to the indicators of energy consumption in the
nodes. The results show that the use of the algorithm leads to a significant improvement in
the network life ranges between 2 and 4 times, according to the allowing the nodes to sleep
and wakeup, or not, for different transmission rates where the scenarios have been tested
for ZigBee based wireless sensors networks using NS-2 simulator.
The use of wireless sensor networks to monitor and control the precise agriculture is one of the areas which received broad concern in recent times, for the services, facilities and the reliability provided by these networks on the monitoring and con
trol level.
This research contributes to the study of the application of this technique in greenhouses deployed over large areas in our country. It offers solutions for networks of monitoring and control, in real time, and ensures a good performance according to the essential evaluating criteria, such as reducing the time-delay, and increases throughput, increases the delivery ratio of packets, and reduces the number of packets lost along with increased network load.
In order to do that, a number of scenarios are proposed. These scenarios are similar to the reality of the construction and operation of the greenhouses in our region relying on ZigBee technique. Wireless sensors networks of these scenarios have been tested, using simulation in order to make conclusion and recommendations to guide the work while installing such networks in place to work as their best for different areas and a large number of lounges
Wireless Sensor Networks (WSN) have applications in many different areas of life, such as health care, environmental monitoring, and military and economic areas and in industrial automation and many other applications.
The development of these net
works and the improvement of their performance occupy an important place of interest in research centers and specialized scientific institutes. The interest in these structures as a way to improve the performance of these networks leads to good results in this area. The cluster structure is one of the most important structures that have received increasing attention over recent years.
This research suggested a modification of the structure of the cluster tree WSN dividing clusters into sub-groups, and each group of these sub-groups operates like a tree from a small amount of nodes. The results that have been obtained by means of simulation indicate a significant improvement in terms of reducing energy consumption and thus an increase in the lifetime of the network, as compared to traditional cluster tree WSN. But that was at the expense of slightly lower rates of transmission and delivery ratio in the nodes of these networks. This leads us to recommend using this method to build the networks used to monitor protected agriculture and other networks with low transmission rates.
Compressive Sensing (CS) shows high promise for fully distributed
compression in wireless sensor networks (WSNs). In theory, CS
allows the approximation of the readings from a sensor field with
excellent accuracy, while collecting only a small fra
ction of them at
a data gathering point. However, the conditions under which CS
performs well are not necessarily met in practice. CS requires a
suitable transformation that makes the signal sparse in its domain.
Also, the transformation of the data given by the routing protocol
and network topology and the sparse representation of the signal
have to be incoherent, which is not straightforward to achieve in
real networks. In this paper we investigated the effectiveness of
data recovery through joint Compressive Sensing (CS) and
Principal Component Analysis (PCA) in actual WSN deployments.
We proposed a novel system, called CS-PCA that embeds a
feedback control mechanism to automatically change the
compression ratio through changing the number of transmitting
sensors, while bounding the reconstruction error. The considered
recovery techniques in the proposed system are: biharmonic Spline
(Spline), Deterministic Ordinary Least Square (DOLS),
Probabilistic Ordinary Least Square (POLS) and Joint CS and PCA
(CS-PCA). We found that the later outperform all other
interpolation technique in the case of slow varying signals, while
POLS was the most effective in case of fast varying signals that(
low correlation less than 0.45)
The low cost, ease of deployment has exposed WSNs an attractive choice for numerous applications,like environmental monitoring applications , security applications, real time tracking, and so on.
But in reality, these networks are operated on batte
ry with limitations in their computation capabilities, memory, bandwidth ,so they called networks with resource constrained nature, and this impels various challenges in its design and its performance.
Limited battery capacity of sensor nodes makes energy efficiency a major and challenge problem in wireless sensor networks. Thus, the routing protocols for wireless sensor networks must be energy efficient in order to maximize the network lifetime.
In this paper we simulated LEACH,SEP,DEEC,TEEN routing protocols and evaluated their performance by comparing with DT routing protocol in Homogeneous and Heterogeneous Wireless Sensor Networks on MATLAB.
Wireless sensor networks (WSNs) are often deployed by random bestrewing
(airplane bestrewing for example). A majority of nodes cannot obtain their coordinate
beforehand. Therefore, how to obtain the position information of unknown nodes, which is
called localization problem, has become a hot topic in WSN.
Without position information, WSN cannot work properly. Global Position System
(GPS) is the most extensive and mature position system at present. But because the nodes
usually have the shortcoming of high expenditure, large volume, high cost and require
settled basal establishment, therefore, the GPS is inapplicable for the low-cost selfconfigure
sensor networks, and also it is impossible to install GPS for each sensor node. In
this paper, we will study localization mechanisms (which is not based on GPS) used in
WSN, and will test the effectiveness of using MUSIC algorithm in determining the signal
arrival angel depending on the SDMA- technology and ESPAR antenna.
The dynamic clustering-based hierarchical routing protocols are one of the methods
used to save energy and increase the lifetime of wireless sensor networks, however, that
most of the researches are neglecting the energy expended in election of the
heads and
formation of clusters in the network.
In this paper, we examine the overhead energy caused by hierarchical routing
protocols based on dynamic clustering and study its impact on the stability period of the
wireless sensor networks. Also, we proposed a solution to limit this energy by reducing the
consumed energy in election of heads and clusters formation operations. It is shown
through the simulation results that the energy consumed in LEACH setup phase decreases
the stability period of these networks and increases the number of dead nodes. And the use
of the proposed solution reduced the energy consumption during the election of the heads
and the formation of clusters clearly compared to the normal way followed in LEACH,
which has increased stability period and the number of live nodes in the network.
A lot of research directed its concern to the reliability of Wireless Sensor Networks
(WSNs) used in various applications, especially in early detection of forest fires to ensure
the reliability of warning alarms sent by sensors and reduce the aver
age of false warnings.
In this research we have tried to evaluate the reliability of WSN used in early
detection of fires in Fir and cedar preserve, mainly. By designing hybrid WSN network,
similar to the terrains of the preserve and modeling it using program Opnet14.5. We have
studied several scenarios, to allow increasing malfunction of the network resulting from
fire break out and spreading: starting in allowance of 0% and comparing its results the
results of mathematical equations of reliability according to the same scenarios. In
addition, we have calculated the final availability through suggesting a mechanism to
improve WSN reliability using the redundancy, i.e add sensitive spare nodes, which
replace the damaged ones as the result of fire. The results have proved the remarkable
increasing of reliability. Also, it has been predicted of the reliability of the network
designed according to reliability of different values of the nodes used by using one of the
reliability devices "the Block Diagram".
Wireless Sensor Networks (WSNs) are deployed in adversarial environments and
used for critical applications such as battle field surveillance and medical monitoring, then
security weaknesses become a big concern. The severe resource constraints of
WSNs give
rise to the need for resource bound security solutions.
The Implicit Geographic Forwarding Protocol (IGF) is considered stateless, which
means that it does not contain any routing tables and does not depend on the knowledge of
the network topology, or on the presence or absence of the node in WSN. This protocol is
developed to provide a range of mechanisms that increase security in IGF. Thus it keeps
the dynamic connectivity features and provides effective defenses against potential attacks.
These mechanisms supported the security against several attacks as Black hole, Sybil and
Retransmission attacks, but the problem was the inability of mechanisms to deal with
physical attack.
This research deals with a detailed study of the SIGF-2 protocol and proposes an
improvement for it, in which we use the concept of deployment knowledge from random
key pool algorithm of keys management to defend against physical attack . The evaluation
of simulation results, with different parameters, proved that our proposal had improved the
studied protocol.
