Dogan Yildiz

GreenCloud simulation QoSbox in cloud computing

Cloud computing was introduced as a new technology when local resources could not any more fullfil access requirements along with the increase of network bandwidth and variety of services breaks constraints of physical placement and deliver diversities of services in its virtualized hardware and software type. GreenCloud simulator as an extension of the Network Simulator (NS-2) cloud computing simulators, execute an energy-aware cloud computing scenario with data center virtualized components (switches, routers, links, etc.). This paper converses a cloud architecture that delivers virtualized network as per demand from cloud user, with the explanation of QoSbox-based GreenCloud simulation that to demonstrate the performance and behavior of the nework performance in cloud computing environment.

A Novel Self Localization Approach for Sensors

This paper presents a modification of 3N Time of Arrival (TOA) and a reliable Time Difference of Arrival (TDOA) based localization algorithms. TDOA is formulated using the parametric equations of the hyperbolas whose intersections are candidate locations for the nodes to be localized. The TDOA algorithm is guaranteed to find all possible relevant solutions, even when implemented on a computational node with limited capability. Monte- Carlo simulations were used to assess the performance for both algorithms.

Transmission of audio signal from linear block coded AWGN channel using different modulation techniques and wavelet transform families

Mobile communication has become an important part of our daily lives for voice communication and data sharing and access over the Internet. Mobile communication is an open network, so maintaining the privacy and reliability of data has always been anxiety. The reliability of the data against channel noise can be achieved by various error correction codes. The purpose of the channel coding process is to reduce the effect of some disruptive elements that the information is influenced in the transmission phase as much as possible, that is to ensure that the data is delivered to the receiver with minimum error. In the first1 part of this work, Linear Block Coding Method is used to transmit the audio data recorded in .wav format for 5 seconds in MATLAB environment with minimum error. Four different types of modulation were used as the modulation method and the best performance was obtained by using Binary Phase Shift Keying (BPSK). The Bit Error Rate (BER) performance curve was drawn and the difference between the original and the received signal was observed. According to the BER performance curve, as the signal to noise ratio increases, less false data is received at the receiver. In the second part of the study, four wavelet transforms at different levels were applied to the audio signal, and the performances of these families were compared.

A hyperbolic location algorithm for various distributions of a Wireless Sensor Network

Intersection of hyperbolic curves defined by the Time Difference of Arrival (TDOA) is often used in Wireless Sensor Networks (WSNs) to estimate the location of sensors. This paper proposes a new algorithm of this type. The hyperbolic parametric equation and the rotation matrix are used to estimate the location of the target node and rotation, translation and intersection operations are applied. MATLAB simulations on Uniform, Beta, Weibull and Gamma distributed networks showed the optimum combinations of distribution, constant range and anchor percentage.

Assessment of short/long term electric field strength measurements for a pilot district

The level of electromagnetic radiation (EMR) exposure increases day by day as natural consequences of technological developments. In recent years, the increasing use of cellular systems has made it necessary to measure and evaluate EMR originating from base stations. In this study, broadband and band selective electric field strength (E) measurements were taken at four different times in order to evaluate the change of short term E in Atakum district of Samsun, Turkey. The measurements were collected from 46 different locations using PMM 8053 and SRM 3006 EMR meter in band from 100 kHz to 3 GHz, and the maximum E (Emax) and the average E (Eavg) were recorded. The highest values have been noticed in these measurement 9.45 V/m and 17.53 V/m for Eavg and Emax respectively. Apart from these measurements, 24 hour long term E measurements were taken at a location where the highest value was observed and analyzed to observe the change of Es during a day. At the end of the study an empirical model that helps calculating the total E of medium with 95% was proposed.

mN/2 algorithm to resolve uncertainty of sensors localization

This paper introduces a novel graph-theoretic self localization algorithm that resolves ambiguities in the position candidates. The algorithm is especially effective in very sparse networks where other algorithms usually fail. Even when the algorithm cannot locate a given node, it produces a polygonal estimate of the region in which the node is located. Monte Carlo simulations show that this algorithm performs better than other well known algorithms.

Three-Dimensional Sensor Localization Using Modified 3N Algorithm

Wireless sensor networks are popular technologies that have extensive application areas. Localization is a crucial topic in wireless sensor networks. In wireless ad hoc and sensor networks, supporting nodes without Global Positioning System (GPS) capability have many applications in routing and surveying systems in use today. Time of Arrival (TOA) is a method used to estimate the location of a target node based on the correlation of the signals. In this paper, before proposing the Modified 3N algorithm in 3D, the 3N algorithm and Modified 3N algorithm in 2D are expressed. In the Modified 3N algorithm in 3D, four spheres were used to localize the target node in the algorithm. Nodes that are localized are now position-aware and possess the capability to share their positions. This newly found position-aware node is introduced into the pseudo anchor list. The neighboring network is intimated of this change and the gradual increase in the position-aware nodes in the network enable an enhanced localization performance. The simulations conducted have shown that the introduction of the knowledge of newly localized nodes into the network enhances its localization capability. The enhancements in both 2D and 3D environments are shown using MATLAB simulations and the obtained results are discussed.

The use of different differential equation algorithms to calculate online transmission line parameters and fault location

Differential equation algorithm (DEA), which is used as an alternative method to Fourier and similar algorithms, is among the online parameter estimation algorithms used in transmission line protection. Pi or T equivalent circuit parameters (R, L and C) of the transmission line can be calculated efficiently by using the fundamental harmonic components of voltage and current. DEA is a general model-based parameter estimation method and it does not depend on the form of the signal (voltage / current). Due to this feature DEA provides an efficient parameter estimation. In addition to traditional trapezoidal DEA algorithm, Simpson 1/3, Simpson 3/8, Simpson, 7, Medium Point, Forward Euler and Boolean algorithm were first proposed in this study and the parameter estimations were performed on an exemplary transmission line. Thusly, it is proven that alternative methods can be used effectively on relays as an algorithm to find the location of a fault in the line.

Estimation of online transmission line parameters and fault location by using different differential equation algorithms

Differential Equation Algorithm (DEA), which is used as an alternative method to Fourier and similar algorithms, is among the online parameter estimation algorithms used in transmission line protection. Pi or T equivalent circuit parameters (R, L and C) of the transmission line can be calculated efficiently by using the fundamental harmonic components of voltage and current. DEA is a general model-based parameter estimation method and it does not depend on the form of the signal (voltage/current). Due to this feature DEA provides an efficient parameter estimation. In addition to traditional trapezoidal DEA algorithm, Simpson 1/3, Simpson 3/8, Simpson 7, Medium Point, Forward Euler, Backward Euler, Runge-Kutta and Boolean algorithms were first proposed in this study and the parameter estimations were performed on an exemplary transmission line. Thusly, it is proven that alternative methods can be used effectively on relays as an algorithm to find the location of a fault in the line.