Theses supervised by Yrd. Doç. Dr. Sibel Tarıyan Özyer
10 theses · Çankaya University
An efficient energy scheme for hybrid clustering wireless sensor networks
Wireless network clustering is one of the major methods which have been used in many applications for energy optimization. As there are many nodes in networks, our aim is to provide adaptive energy consumption with clustering methods. LEACH is a famous algorithm for clustering, which depends on random clustering method. In this algorithm, there are two different types of node, namely the cluster head and cluster members. Communication is provided via these cluster heads. Therefore, the LEACH algorithm achieves its main purpose by providing dynamic clustering and adaptive energy consumption. In this thesis, a new hybrid clustering algorithm is introduced, analyzed and implemented in a network area. The energy performance of the proposed method is compared with LEACH (Low Energy Adaptive Clustering Hierarchy) and SEP (Stable Elections Protocol). Cluster head selection with different constraints and methods achieves better results in cases of energy consumption.
Energy efficiency in wireless sensor networks
Wireless Sensor Networks (WSNs) are consists of small sensor nodes with limited battery power, processing and memory units. There are two important features in WSNs. The first one is the infrastructure-less and second one is the self-organization. These properties make sensors convenient choice for several applications. When we try to investigate algorithms and protocols for wireless sensor networks we must study the features and constraints of WSNs. However, battery recharge is not possible or extremely challenging for sensor nodes. The main aspect in designing wireless sensor networks algorithms and protocols is ensuring energy efficiency and prolong the sensor network lifetime. Farther more the sensor node position within the set of deployed nodes decides which tasks have to be carried out and how many communication paths involve each individual sensor node. On the other hand the sensor networks in more obstructed environments, the path loss exponent value is vary. The high path loss exponent value increases unbalance energy depletion between nodes. In this thesis we investigated two node deployment strategies which are uniform and non-uniform (normal distribution) sensor node deployments with various path loss exponent values. We used a Linear Programming (LP) framework to analyze the effect of node deployment model on the network lifetime. Also we studied the effect of path loss on the wireless sensor network lifetime. Our results showed that by normal node deployment, energy balance can be improved up to certain level. However, increasing path loss exponent in normal node deployment may lead to decrease in improvement ratio.
Copyright protection using digital watermarking
The digital techniques have greatly smooth data representation and data storage. However, the content of the data without distortion is easy to edit and copy in digital media, and this situation has resulted in a series of security problems over the widespread of using the network. For example, users can easily access, edit, or distribute data in digital media. Therefore, how to guarantee copyright protection and the integrity of the content of digital media has become an emergent issue. Digital watermarking has been proposed as a solution to the problem of resolving copyright ownership of multimedia data (image, audio, and video). In this thesis, we have proposed a copyright protection using private watermarking algorithm. The algorithm is based on multi techniques of frequency domain such as: Two Dimensional Discrete Cosine Transform and Multi-Level Two Dimensional Discrete Wavelet Transform. The proposed algorithm is built by using the secret key which is coded in the embedding side by using the secure hash algorithm (SHA-1) to increase the security of the proposed study. In this thesis, we used some fidelity criteria (such as: the peak signal to noise ratio, the normalized cross correlation and the normalized hamming distance) for measuring the performance on some different standard gray scale images. The robustness of the proposed algorithm was tested on different types of noises.
Optimizing energy consumption in wireless sensor networks by using linear programing equations
Wireless Sensor Networks (WSNs) it is set of sensors deployed in a specific geographic area to sensing particular action, then relays the data to one or more base station to manage it and take actions. Sensors are tiny devices supported with limited power source generally, represented by the battery. These sensors are designed to work in unattended fields for a long time months or years. So sensor life is the most important factor in the network. We have to extend sensor lifetime as much as possible to prolong the network lifetime. Hence the network lifetime can be defined as a time from running the network till they die off first nodes in the network. Therefore, we try to make energy consumption in the network that is controlled and balanced among sensors, avoiding dies one or more sensor before the others. Many methods and manners can be used to save energy and improve network lifetime, such as data aggregation, mobile nodes, transmission power control, node deployment, and clustering. In this thesis, the problem of "unbalance energy consumption" has been studied to maximize network lifetime as much as possible in the wireless sensor networks. In such networks, all sensor nodes collect and transmit data to one base station through multi-hop communications. The nodes deployment is uniform. This situation generates heavy traffic load in the nodes near to the base station. In this study, a linear program (LP) method has been studied for modeling the theoretical features of the uniform node distribution strategies in wireless sensor networks. Our results indicated that node deployment and base station location have significant effects on the energy consumption of sensor nodes. Proposed node deployment models can affect the energy consumption and can balance energy depletion between sensor nodes. Keywords: Wireless Sensor Network, Network lifetime, Node deployment, Linear Programing.
E-recruitment perceptions: Importance,processes and requirements
Nowadays, the old-style methodology of recruitment has been transformed with the concept of on-line recruitment, or what we can abbreviate to e-recruitment. Because of the increasing number of end users of the Internet globally, e-recruitment has developed rapidly in recent years. E-recruitment has opened the way for new concepts in employment with easy to access to information, easy management and savings in time for both workers and employers. The main objective of this research is to demonstrate the importance of e-recruitment to any enterprise and to discuss the impact of using the medium of the Internet as a channel for the recruitment process. In addition, this study endeavors to show how we can decrease the overall cost of the recruitment process, and how to provide a more integrated functionality to the recruitment process in addition to identifying the benefits of e-recruitment for both employers and applicants. Moreover, this study suggests e-recruitment for the University of Kirkuk as a case study. An e-recruitment system implementation at the University of Kirkuk is also discussed in addition to identifying the benefits of using an e-recruitment system to jobseekers and stating the impact of e-recruitment in improving the human resources management mechanism. Finally, a number of recommendations by the researcher are presented regarding financial and administrative issues
Performance comparison of multi-core smartphones
Smartphones are an important communication tool, having tendency to emerge as the mobile computer, that is, presenting all functions needed on the way of an individual. Subsequently, multi-core smartphones have been manufactured, therefore applying parallel processing on these devices have become possible. Using parallel processing in smartphones has many advantages, such as reducing processing time, power optimization, use the full power of the smartphone and giving us the ability to write more efficient applications. In this thesis, the way to write parallel applications will be investigated on multicore smartphone, and analyzed the dependency for the applications with the purpose of determining the parts of the code within the application that will be implemented in parallel. The Bernstein's conditions will be applied which describe when two program fragments can be executed in parallel. The way determining the most favorable quantity of threads will be indicated to be used in parallel application. The success in gain of performance will be attained by parallel processing of application on more than one processor, or what is called Speedup. Java 2 Micro Edition (J2ME) will be used as a programming language to develop mobile phone applications and Android Studio as a developing environment.
Adaptive energy consumption method for wireless sensor networks using optimization algorithms
The objective of this thesis is to save the nodes energy using optimization approach with Particle Swarm Optimization Algorithm. The network area is divided to several regions for parametric study. In the proposed method, the energy of the efficient routing is enhanced and the system used the Particle Swarm Optimization for eliminate the individual nodes in wireless sensor network. In this thesis the optimization method is used to find the best hop in wireless sensor network which use the Gravitational Search Algorithm. The proposed work compared with Low Energy Adaptive Clustering Hierarchy. In simulation result the total energy for proposed method is got 8 Joules, which the energy for the OEERP is got 10 Joules and for the LEACH the 20 Joules is got. That's mean proposed method is 20% better than the energy consumption from optimized energy efficient routing protocol and 60% better than the Low Energy Adaptive Clustering Hierarchy method is reduced. In proposed method the packet delivery ratio is high than the optimized energy efficient routing protocol and Low Energy Adaptive Clustering Hierarchy method. As result the packet delivery is 100. This values only the base value and for 4000 bit packet that time 400,000 packet will send to the base station. The packet delivery for v optimized energy efficient routing protocol is 60 and for Low Energy Adaptive Clustering Hierarchy this value is 64. Keywords: Wireless Sensor Network, Particle Swarm Optimization Algorithm, Clustering Method
Cloud computing impact on communication and service sector: Iraq case study
Rapid advancements in technology have enhanced the significance of the use of cloud technology. The deployment of cloud computing as effective technology integration has been successful, particularly across the developed states of the world. However, there have been certain behavioural issues regarding the cloud technology activation in certain developing regions, rather than the technical limitations. In the context, the current research aims to evaluate the impact of deployment of cloud computing on the communication and service sector of Iraq. Even though the cloud computing approach seems appealing, yet certain challenges of adverse extent are encountered across the states where internet penetration and technology acceptance is not considerable. Similar is the case with Iraq; hence, the researcher has targeted the communication and service sector of Iraq with respect to assessing the deployment of cloud computing. In this regard, the constructs of UTAUT model as identified dependent and independent variables of the study have been employed, in terms of conducting a multiple-item 5-point scale online survey across 251 IT experts of the targeted domain. Resultantly, it has been established that there have been certain challenges of disregarding cloud computing as an effective measure of enhancing productivity, and efficiency of the employees in a secure and feasible manner. Therefore, the study has recommended training and awareness programs that must present the credibility and integrity of cloud computing as an effective technological deployment. These programs assist accepting the cloud computing technology by the employees in the communication sector, which enables the employees, as well as the organizations, providing more efficient tasks by reducing the costs and efforts needed to perform the exact same tasks without the use of cloud computing technologies. This improvement also assists other employees and organization to accept that technology, which eventually leads to more and more acceptance to the cloud computing technology in the communication and service sector. Keywords: Cloud Computing, UTAUT, Communication Sector, Service Sector, Productivity Effectiveness
Unified threat management (UTM): A comparative study
Network security has been the foremost need of the technologically advanced world, when considering the implications in the business environment. It has been affirmed that the business enterprises have intensively become susceptible to the data theft or data breaching attacks over the internet; thus, credibility of the processes has been affected. Businesses that lack in being considerate towards the competitive needs of the strategies tend to face declining performance. It leads to the assertion that the decision making process of the businesses must be based on the deployment of continuous improvement prospects. In this thesis, we assessed the business stance of an Imaginary Organisation that led to the assertion that the current network infrastructure of traditional firewall needs to be upgraded. The existing traditional firewall has been disabled to standing against security threats such as Denial of Service, SQL injection, email viruses ..etc. Therefore, the study has been proposed to the migration plan of an Imaginary Organisation network that serve 200 users with developed security services. The plan has been presented to the UTM as advanced features security solution. In order to select the best UTM that satisfied the demands of an Imaginary Organization security requirements, a comparison study among four commercial UTMs has been held. This study achieved by using a virtual lab that consistent from a multi virtual machines that was used as a test environment. The four UTMs have been assessed based on the attributes of visions, execution, ease of use, web-interfaces, device performance, throughput capacity, intrusion prevention system features along with the guaranteed elements of security and many other factors. The experimental work includes installation and test of the software's such as SONICWALL, SOPHOS XG Firewall, WarchGuard, and Palo Alto Networks. The researcher also analyses the impacts of Gartner's reviews along with testing lab result to come out with conclusions that the UTM device called SOPHOS XG Firewall was the best tested device based on study criteria. This device provides the most significant security features affordably. SOPHOS XG Firewall provides the security features such as email protection, Unknown Application Identification, along with the element of Full-Featured Web Application Firewall that able to prevent SQL injection attacks and Denial of service ..etc which traditional firewalls and other UTMs may not be capable of doing. Moreover, the study has presented details in this regard, along with the clearly articulated recommendations as well. Keywords: Unified Threat Management, Network Security, Advanced Threat Protection.
An approach to solve campus network security problems at three layers of OSI model
With expanding dependence on computer systems all around the world for information storage and data processing, the requirement for legitimate security of data and information cannot be overemphasized. Destruction or revelation of data and unauthorized access can violate people's privacy and threaten the presence of an institution, as information is considered the live wire of an institution. Therefore, it is a necessity to secure the stored information and computer systems. The customary method for securing computer networks, such as software encryption and firewalls are ineffective and insufficient. There is a probability that the network is exposed to harm or physical attack due to its feature of management and monitoring point not being centralized, open medium dynamic changing topology, cooperative algorithms and clear line not well defended. This thesis recognizes many kinds of threats in campus network related to three layers of OSI model (physical, data-link, and network), and proposes several practical solutions from network infrastructure perspective. This study covers three main parts; first, building a campus network with principal security aspects (default configurations). The second part, addressing network's flaws, vulnerabilities and weak points that represent a back door for the network and threaten C.I.A. means (Confidentiality, Integrity and Availability). Moreover, the first important step to know the level of threat is addressing network's flaws. All threats come with three layers will be identified in this study. Also, a solution will be offered for each threat and an example will be given for each solution. Finally, as a part of evaluating the network security, some kinds of attacks will be made (before and after) applying security technologies. The theoretical results of this study represent a reference model for a campus network security through first three layers (P., D., N.) that can be adopted as a good practice to build and secure a robust campus network for the deep information affixed to each part within the three layers. The details will include many recommendations and will be covered at design and implementation of the campus network. The final result in this study gives a bright view about how much we have gained resources and offered more services with guaranteeing information secrecy, service availability, full mean of confidentiality. Decreasing the effect of attacks and increasing the uptime are extra benefits of this study.