• Transmission of multi-dimensional-taliem-ir

    Transmission of multi-dimensional signals for next generation optical communication systems

    تومان

    Over the past several decades, the data-carrying capacity of a single optical fiber have been increased significantly by fully exploring and optimizing physical dimensions of the light. Generally there are five major candidates of dimensions, including time, wavelength, polarization, space and quadrature (phase and amplitude). Multidimension, utilizing more than two dimensions of the light simultaneously, is one of the essential characteristics of next generation optical communication systems. We review recent advances in transmission of multidimensional signals, and highlight innovative ways of exploring the  polarization dimension to further increasethe capacity or spectral efficiency of a single optical fiber, a so-called pseudo-polarization-division-multiplexing (PPDM) technique. Related demonstrations include non-orthogonal PDM, PPDM of three and four states (PPDM- 3 and PPDM-4). Brief discussions on trends of multi-dimensional signal transmission technologies are also presented.

  • Trilateration Target Estimation-online-taliem.ir

    Trilateration Target Estimation Improvement using New Error Correction Algorithm

    تومان

    Applying Trilateration concept for target localizing demands measuring distance between target and at least three recognized reference points. The errors of measured radiuses due to the accuracy of applied measurement technique resulted large divergence in Trilateration localizing. The presented paper utilized standard Trilateration calculations with a view to likely measurement error, and then a new algorithm is presented to improve calculated target’s position. The new Error Correction Algorithm is a good alternative for standard Trilateration calculations. It is easy to implement, isolated from applied measurement  technique .Since ECA is isolated from the applied distance measurement technique, it examined the practical result of distance measurement based on received signal strength (RSS) technique. Although practical distance measurement had great offset from actual values but ECA could lessen the offset error by more than 50%.

  • Trust in driverless cars-taliem-ir

    Trust in driverless cars: Investigating key factors influencing the adoption of driverless cars

    تومان

    Driverless cars are seen as one of the key disruptors in the next technology revolution. However, the main barrier to adoption is the lack of public trust. The purpose of this study is to investigate the key factors influencing the adoption of driverless cars. Drawing on quantitative evidence, the study found that the ability of the driverless car to meet performance expectations and its reliability were important adoption  determinants. Significant concerns included privacy (autonomy, location tracking and surveillance) and security (from hackers). The paper provides implications for firms developing the next generation of car features and early implementation sites.

  • Trustworthiness Management in the Social[taliem.ir]

    Trustworthiness Management in the Social Internet of Things

    تومان

    The integration of social networking concepts into the Internet of things has led to the Social Internet of  Things (SIoT) paradigm, according to which objects are capable of establishing social relationships in an  autonomous way with respect to their owners with the benefits of improving the network scalability in  information/service discovery. Within this scenario, we focus on the problem of understanding how the  information provided by members of the social IoT has to be processed so as to build a reliable system on the basis of the behavior of the objects. We define two models for trustworthiness management starting  from the solutions proposed for P2P and social networks. In the subjective model each node computes the trustworthiness of its friends on the basis of its own experience and on the opinion of the friends in common with the potential service providers. In the objective model, the information about each node is distributed and stored making use of a distributed hash table structure so that any node can make use of the same information. Simulations show how the proposed models can effectively isolate almost any malicious nodes in the network at the expenses of an increase in the network traffic for feedback exchange.

  • Underwater wireless optical-taliem-ir

    Underwater wireless optical communication using a lens-free solar panel receiver

    تومان

    In this paper, we first propose that self-powered solar panels featuring large receiving area and lens-free operation have great application prospect in underwater vehicles or underwater wireless sensor networks (UWSNs) for data collection. It is envisioned to solve the problem of link alignment. The low- cost solar panel used in the experiment has a large receiving area of 5 cm2 and a receiving angle of 20. Over a 1-m air channel, a 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal at a data rate of 20.02 Mb/s is successfully transmitted within the receiving angle of 20. Over a 7-m tap water channel, we achieve data rates of 20.02 Mb/s using 16-QAM, 18.80 Mb/s using 32-QAM and 22.56 Mb/s using 64-QAM, respectively. By adding different quantities of Mg(OH)2 powders into the water, the impact of water turbidity on the solar panel-based underwater wireless optical communication (UWOC) is also investigated.

  • Unified Power Flow Controller (UPFC) Based Damping Controllers[taliem.ir]

    Unified Power Flow Controller (UPFC) Based Damping Controllers for Damping Low Frequency Oscillations in a Power System

    تومان

    This paper presents a systematic approach for designing Unified Power Flow Controller (UPFC) based  damping controllers for damping low frequency oscillations in a power system. Detailed investigations have been carried out considering four alternative UPFC based damping controllers. The investigations reveal that the damping controllers based on UPFC control parameters δE and δB provide robust performance to  variations in system loading and equivalent reactance Xe.

  • Unit commitment by dynamic programming for[taliem.ir]

    Unit commitment by dynamic programming for microgrid operational planning optimization and emission reduction

    تومان

    This paper presents a 24 hour ahead microgrid power planning using the approach of unit commitment by dynamic programming. The studied system comprises twelve PVbased active generators with embedded storage and three micro gas turbines. Based on the prediction of the energy available from the PV generator, the storage availability, the micro turbine emission characteristics and the load prediction, a central energy management system calculates a 24-hour ahead plan of the power references for three micro gas turbines and the active generators in order to minimize the CO2 equivalent emissions of the gas turbines.

  • Using fuzzy Ant Colony-online-taliem.ir

    Using fuzzy Ant Colony Optimization for Diagnosis of Diabetes Disease

    تومان

    Ant colony optimization (ACO) has been used successfully in data mining field to extract rule based classification systems. The Objective of this paper is to utilize ACO to extract a set of rules for diagnosis of diabetes disease. Since the new presented algorithm uses ACO to extract fuzzy If-Then rules for diagnosis of diabetes disease, we call it FADD. We have evaluated our new classification system via Pima Indian Diabetes data set. Results show FADD can detect the diabetes disease with an acceptable accuracy and competitive or even better than the results achieved by previous works. In addition, the discovered rules have good comprehensibility.

  • Visual Cryptography Based-taliem-ir

    Visual Cryptography Based Multilevel Protection Scheme for Visualization of Network Security Situation

    تومان

    Visualization technology for network security situation adopts images to present the massive abstract data regarding network events. It reduces the workload of data analysis and benefits the manager to grasp the overall network status and trend. Secret information in the visual image requires confidentiality protection while transmitting. Comparing with some conventional methods real zed by compl cated encryptions such as DES and AES, we present a novel multilevel protection scheme based on visual cryptography (VC) with the beauty of decryption done only via the human eyes without using more computing devices. Essentially, a region incrementing VC scheme (RIVCS) is proposed in this paper dealing with the encoding of a secret situation image regarding network security. The secret image includes a number of regions, where each region is allocated with a certain secrecy level. Different secrecy levels can be decoded incrementally when different combinations of participants are gained. Firstly, we develop the model called the general AS (GAS) based RIVCS. Secondly, we design the algorithm for allocating secrecy levels. Thirdly, we construct encoding matrices for sharing the s ret pixels. Experiment results show that our method is more suitable to visualization data protection for network security situation with lower cost, higher reliability and richer application scenarios.

  • Voltage support in industrial distribution systems in presence[taliem.ir]

    Voltage support in industrial distribution systems in presence of induction generator-based wind turbines and large motors

    تومان

    Industrial loads are usually composed of large induction motors (IM). These motors present a critical behavior under some circumstances, e.g. during starting and faults in the system. Currently, induction generator-based wind turbines are also connected to distribution systems.  Essentially, these generators present the same behavior of large IM and, when directly connected to the system, their interaction can increase voltage sag levels or even lead the system to a voltage collapse. These generators, however, are usually provided with specific controls or power electronic-based equipment to comply with the voltage ride-through capability required by the grid codes. These resources, however, can be used to minimize the impact of large motors in the grid or even minimize their impact on voltage sags caused by faults in the system. In this context, this paper has the objective of analyzing the impact of different technologies used in induction generator-based wind turbines during disturbances in distribution systems in the presence of large IM. The analysis aims to clarify the potential benefit of wind turbine  allocation at the demand side of an industrial power distribution system. Based on the results, an adapted control scheme, considering the control strategies currently available, is proposed for the grid side converter of the doubly fed induction generators to improve power quality.

  • Voltage Unbalance Emission Assessment[taliem.ir]

    Voltage Unbalance Emission Assessment in Radial Power Systems

    تومان

    Voltage unbalance (VU) emission assessment is an integral part in the VU-management process where loads are allocated a portion of the unbalance absorption capacity of the power system. The International  Electrotechnical Commission Report IEC/TR 61000-3-13:2008 prescribes a VU emission allocation  methodology establishing the fact that the VU can arise at the point of common connection (PCC) due to upstream network unbalance and load unbalance. Although this is the case for emission allocation,  approaches for post connection emission assessment do not exist except for cases where the load is the only contributor to the VU at the PCC. Such assessment methods require separation of the post connection VU emission level into its constituent parts. In developing suitable methodologies for this purpose, the pre and postconnection data requirements need to be given due consideration to ensure that such data can be easily established. This paper presents systematic, theoretical bases which can be used to assess the individual VU emission contributions made by the upstream source, asymmetrical line, and the load for a radial power system. The methodology covers different load configurations including induction motors. Assessments obtained by employing the theoretical bases on the study system were verified by using unbalanced load- flow analysis in MATLAB and using DIgSILENT PowerFactory software.

  • Voltage-Based Control of a Smart Transformer[taliem.ir]

    Voltage-Based Control of a Smart Transformer in a Microgrid

    تومان

    For the islanded operation of a microgrid, several control strategies have been developed. For example, voltage-based droop control can be implemented for the active power control of the generators and the control of the active loads. One of the main advantages of a microgrid is that it can be implemented as a controllable entity within the electrical network. This requires the ability of the utility grid to control or influence the power exchange with the microgrid by communicating with only one unit. However, little research has been conducted on controlling the power transfer through the point of common coupling. This paper addresses this issue by introducing the concept of a smart transformer  (ST) at the point of common coupling. This unit controls the active power exchange between a microgrid and the utility grid dependent on the state of both networks and other information communicated to the ST. To control the active power, the ST uses its taps that change the microgrid-side voltage at the PCC. This voltage-based control of the ST is compatible with thevoltage-based droop control of the units in the  microgrid that is used in this paper. Hence, the microgrid units can automatically respond to changes of ST set points and vice versa. Several simulation cases are included in this paper to demonstrate the feasibility of the ST concept.

  • Wind Driven Induction Generator Study with Static[taliem.ir]

    Wind Driven Induction Generator Study with Static and Dynamic Loads

    تومان

    This paper presents the performance of a stand-alone self-excited induction generator (SEIG) under balanced/ unbalanced excitation with balanced RLC and dynamic load .Squirrel cage induction motor has been taken as a dynamic load. SEIG is driven with fixed pitch wind energy system. An approach based on three-phase induction machine model is employed to derive dynamic equations of an isolated SEIG under balanced/unbalanced conditions of excitation and balanced static and dynamic loads. The SEIG model with balanced/un-balanced excitation and balanced load has been simulated using MATLAB/SIMULINK.

  • astane gozary-taliem-ir

    آستانه گذاري هوشمند تصوير با استفاده از اتوماتاي يادگير و تئوري فازي

    تومان

    آستانه گذاري تصوير اهميت زيادي در بسياري از كاربردهاي پردازش تصوير، بينائي ماشين و شناسايي الگو دارد.  دراين مقاله روش جديد چند مرحله يا براي آستانه گذاري تصوير با استفاده از تئوري فازي و اتوماتاي يادگير ارائه شده است. ابتدا با استفاده از تئوري فازي، ميانگين و انحراف معيار، تصوير به سه ناحيه روشن، تاريك و مبهم افراز ميگردد. سپس براي آستانه گذاري نواحي روشن وتاريك و همچنين ناحيه مبهم تصوير الگوريتم چند مرحله اي طراحي و پياده سازي ميشود. در نواحي تاريك يا روشن با استفاده از ميانگين و انحراف معيار سراسري و در ناحيه مبهم با استفاده از ميانگين و انحراف معيار محلي آستانه گذاري اوليه صورت مي گيرد. مردر حله بعدي آستانه گذاري مذكور با  استفاده از اتوماتاييادگير متناسب با ناحيه تصحيح ميگردد. بررسي آستانه گذاري تصاوير مختلف بيانگر بهبود  چشمگير نتايج با استفاده از الگوريتم پيشنهادي در مقايسه با ساير الگوريتم هاي مورد بررسي مي باشد .

  • ashekar sazi aber piyade.[taliem.ir]

    آشكارسازي عابر پياده با استفاده از ويولت هار و تبديل Houghو مسيريابي آن در قطعه ويدئويي از طريق پارتيكل فيلتر

    تومان

    در اين مقاله از دو واحد استخراج ويژگي به طور موازي استفاده شده است. اين دو واحد به صورت مكمل يكديگر عمل ميكنند. واحد اول از ويولت هار براي تشخيص عابر پياده استفاده ميكند كه يك ديد كلي از محيط خارجي شكل بدن عابر به صورت يك بردار ويژگي متمركز به دست ميدهد. واحد دوم از تبديل Houghبراي تشخيص خطوط راست در اندامها استفاده ميكند و سپس توسط يك پردازشگر به بررسي رابطه منطقي بين طول و عرض اندامها ميپردازد. وجود اين واحد باعث افزايش استحكام الگوريتم نسبت به انسدادهاي جزئي ميشود. نتايج به دست آمده حاكي از توانايي بالاي اين الگوريتم در تشخيص عابر پياده ميباشد. در ادامه از نتايج آشكارسازي به منظور انجام مسيريابي توسط پارتيكل  فيلتراستفاده ميشود. انجام اين كار باعث بازيابي تشخيص هاي گم شده زماني و در نتيجه بهبود عملكرد آشكارسازي ميشود .