Millimeter wave networks, blockage model,[taliem.ir]

The Transitional Behavior of Interference in Millimeter Wave Networks and Its Impact on Medium Access Control

Millimeter wave (mmWave) communication systems use large number of antenna elements that can potentially overcome severe channel attenuation by narrow beamforming. Narrow-beam operation in mmWave networks also reduces multiuser interference, introducing the concept of noise-limited wireless networks as opposed to interference-limited ones. The noise-limited or interference-limited regime heavily reflects on the medium access control (MAC) layer throughput and on proper resource allocation and interference management strategies. Yet these regimes are ignored in current approaches to mmWave MAC layer design, with the potential disastrous consequences on the communication performance. In this paper, we investigate these regimes in terms of collision probability and throughput. We derive tractable closed-form expressions for the collision probability and MAC layer throughput of mmWave ad hoc networks, operating under slotted ALOHA. The new analysis reveals that mmWave networks may exhibit a non-negligible transitional behavior from a noise-limited regime to an nterference-limited one, depending on the density of the transmitters, density and size of obstacles, transmission probability, operating beamwidth, and transmission power. Such transitional behavior necessitates a new framework of adaptive hybrid resource allocation procedure, containing both contention-based and contention-free phases with on-demand realization of the contention-free phase. Moreover,the conventional collision avoidance procedure in the contentionbased phase should be revisited, due to the transitional behavior of interference, to maximize throughput/delay performance of mmWave networks. We conclude that, unless proper hybrid schemes are investigated, the severity of the transitional behavior may significantly reduce throughput/delay performance of mmWave networks.
Using Petri Nets For Resource Management Modeling[taliem.ir]

Using Petri Nets For Resource Management Modeling In The Operating Systems

Nowadays, with advances in computer science and increase in processor speed, modeling methods have found extensive applications in industrial fields. Petri Nets are one of these modeling methods. Petri Nets are based on graph theory and are applied specifically for concurrent and asynchronous applications. As executable models, they are capable of graphical description of complicated systems. On the other hand, development of hardware and other peripheral computer resources and development of various computer software systems call for efficient and powerful operating systems, sothat users can use the software and hardware items in an effective manner. The purpose of this article is to study the application of Petri Nets for modeling resource management in operating systems with the aim of optimal utilization of resources and Deadlock Avoidance in the Operating Systems.
Selected parallel optimization methods for[taliem.ir]

Selected parallel optimization methods for ®nancial management under uncertainty

A review of some of the most important existing parallel solution algorithms for stochastic dynamic problems arising in ®nancial planning is the main focus of this work. Optimization remains the most dicult, time and resource consuming part of the process of decision support for ®nancial planning under uncertainty. However, other parts of a specialized decision support system (DSS) are also brie¯y outlined to provide appropriate background. Finally, ®nancial modeling is but one of the possible application ®elds of stochastic dynamic optimization. Therefore the same fairly general methods described here are also useful in many other contexts. Authors hope that the overview of this application ®eld may be of interest to readers concerned with development of parallel programming paradigms, methodology and tools. Therefore special care was taken to ensure that the presentation is easily understandable without much previous knowledge of theory and methods of operations research. Ó 2000 Published by Elsevier Science B.V. All rights reserved.
A Web Enabled Secured System for Attendance[taliem.ir]

A Web Enabled Secured System for Attendance Monitoring and Real Time Location Tracking Using Biometric and Radio Frequency Identification (RFID) Technology

Automated Information Systems has played a major role in the growth, advancement, and modernization of our daily work processes. The main purpose of this paper is to develop a safe and secure web based attendance monitoring system using Biometrics and Radio Frequency Identification (RFID) Technology based on multi-tier architecture, for both computers and smartphones. The system can maintain the attendance records of both students and teachers/staff members of an institution. The system can also detect the current location of the students, faculties, and other staff members anywhere within the domain of institution campus. With the help of android application one can receive live feeds of various campus activities, keep updated with the current topics in his/her enrolled courses as well as track his/her friends on a real time basis. An automated SMSservice is facilitated in the system, which sends an SMS automatically to the parents in order to notify that their ward has successfully reached the college. Parents as well as student will be notified via e-mail, if the student is lagging behind in attendance. There is a functionality of automatic attendance performance graph in the system, which gives an idea of the student’s consistency in attendance throughout the semester.
A Secure Cloud Computing Based Framework[taliem.ir]

A Secure Cloud Computing Based Framework for Big Data Information Management of Smart Grid

Smart grid is a technological innovation that improves efficiency, reliability, economics, and sustainability of electricity services. It plays a crucial role in modern energy infrastructure. The main challenges of smart grids, however, are how to manage different types of front-end intelligent devices such as power assets and smart meters efficiently; and how to process a huge amount of data received from these devices. Cloud computing, a technology that provides computational resources on demands, is a good candidate to address these challenges since it has several good properties such as energy saving, cost saving, agility, scalability, and flexibility. In this paper, we propose a secure cloud computing based framework for big data information management in smart grids, which we call “Smart-Frame.” The main idea of our framework is to build a hierarchical structure of cloud computing centers to provide different types of computing services for information management and big data analysis. In addition to this structural framework, we present a security solution based on identity-based encryption, signature and proxy re-encryption to address critical security issues of the proposed framework.
Semantic Management of Streaming Data[taliem.ir]

Semantic Management of Streaming Data

One of the fundamental challenges facing the unprecedented data deluge produced by the sensor networks is how to manage time-series streaming data so that they can be reasoning-ready and provenance-aware. Semantic web technology shows great promise but lacks adequate support for the notion of time. We present a system for the representation, indexing and querying of time-series data, especially streaming data, using the semantic web approach. This system incorporates a special RDF vocabulary and a semantic interpretation for time relationships. The resulting framework, which we refer to as Time-Annotated RDF, provides basic functionality for the representation and querying of time-related data. The capabilities of Time-Annotated RDF were implemented as a suite of Java APIs on top of Tupelo, a semantic content management middleware, to provide transparent integration among heterogeneous data, as present in streams and other data sources, and their metadata. We show how this system supports commonly used time-related queries using Time Annotated SPARQL introduced in this paper as well as an analysis of the TA-RDF data model. Such prototype system has already seen successful usage in a virtual sensor project where near-real-time radar data streams need to be fetched, indexed, processed and re-published as new virtual sensor streams.
Energy optimization of ant colony[taliem.ir]

Energy optimization of ant colony algorithm in wireless sensor network

An energy consumption optimization algorithm based on ant colony algorithm is proposed for wireless sensor network. The proposed algorithm allows each node in wireless sensor network to save the distance and residual energy of neighbor nodes. Furthermore, in terms of probability selection of the nodes and the pheromone update, this algorithm focuses on the next hop node through the comparison of distance between the nodes and the residual energy, which ensures less possibility of nodes with low energy selected as the next hop. Therefore, the proposed algorithm improves energy load balancing, stability of wireless sensor network and, eventually, extends the life span of the wireless sensor network. The simulation results show that the improved ant colony algorithm avoids too much energy consumption of acertain local node resulting in more uniform energy consumption for each node.
A simple power factor calculation for electrical power systems[taliem.ir]

A simple power factor calculation for electrical power systems

The accurately and fast estimation of Phase Difference (PD) is required between the voltage and current of an AC electrical power system to calculate the Power Factor (PF) for defining how effectively the electrical energy is converted into the useful form. Many complex methods based on difficult mathematical equations are presented by the researchers to estimate the PD. In this study, a new and simple algorithm derived by using the trigonometric functions is proposed for PD estimation to calculate PF of a power system. With this method, the fast-time and unaffected by distorted sinusoids of PD estimation are carried out by decreasing the number of mathematical equations. The performance of the proposedmethod is evaluated under the various system conditions by performing the simulation case studies. The results of these studies are given to verify its effectiveness under the distorted system conditions.
New reactive power flow tracing and loss allocation algorithms for[taliem.ir]

New reactive power flow tracing and loss allocation algorithms for power grids using matrix calculation

A novel simple method is suggested in this paper to evaluate the contributions of the sources (including the generators and branches’ charging capacitances) or the loads to the branches’ reactive flows and losses separately as well as to calculate the sources’ shares in providing the loads’ reactive powers. In the method, the study system is first converted to the system, each branch of which only has reactive loss, using a new technique for modeling the generating branches based on the AC load flow results. The properties of two new matrices (i.e. injection-bus and absorption-bus matrices), which are constituted for theobtained system, are then used to derive three other matrices. These matrices, which express reactivepower productions of the sources in terms of reactive power consumptions of the demands (viz. the loads and branches’ losses) and vice versa, contain the intended contributory factors. Three-bus system is applied to demonstrate the computing process of the method whereas several IEEE systems are used to show its capability to implement on the transmission systems with arbitrary topologies and sizes Some advantages of the method compared to the earlier methods are also illustrated.
Fuzzy based damping controller for TCSC using local measurements[taliem.ir]

Fuzzy based damping controller for TCSC using local measurements to enhance transient stability of power systems

This paper proposes a local fuzzy based damping controller (LFDC) for thyristor controlled series capacitor (TCSC) to improve transient stability of power systems. In order to implement the proposed scheme, detailed model of TCSC, based on actual behavior of thyristor valves, is adopted. The LFDC uses the frequency at the TCSC bus as a local feedback signal, to control the firing angle. The parameters of fuzzy controller are tuned using an off-line method through chaotic optimization algorithm (COA). To verify the proposed LFDC, numerical simulations are carried out in Matlab/Simpower toolbox for the following case studies: two-area two-machine (TATM), WSCC three-machine nine-bus and Kundur’s two-area fourmachine (TAFM) systems under various faults types. In this regard, to more evaluate the effectiveness of the proposed method, the simulation results are compared with the wide-area fuzzy based damping controller (WFDC). Moreover, the transient behavior of the detailed and phasor models of the TCSC is discussed in the TATM power system. The simulation results confirm that the proposed LFDC is an efficient tool for transient stability improvement since it utilizes only local signals, which are easily available.