Congestion management Incorporation of FACTS Devices Using Ant Colony Optimization

This paper presents Ant Colony Algorithm (ACA) based approach for the allocation of FACTS (Flexible AC Transmission System) devices for the improvement of Power transfer capacity in an interconnected Power System. The ACA based approach is applied on IEEE 30 BUS System. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is noticed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. Ant Colony Algorithm is then applied to find the amount of magnitudes of the FACTS devices. This approach of ACA based placement of FACTS devices is tremendous beneficial both in terms of performance and economy is clearly observed from the result obtained

New Proxy Blind Multi Signature based on Integer-Factorization and Discrete-Logarithm Problems

Digital proxy multi-signature and blind signature scheme are found very useful for the purpose of electronic voting and electronic cash transaction. In proxy multi-signature, many original signers can delegate their signing power to a proxy signer in such a way that the proxy signer can sign any message on behalf of original signers. In blind signature, the signer cannot make a linkage between the blind signature and the identity of the requester. Proxy blind multi-signature is the combination of proxy multi-signature and blind signature. In this paper, we propose a new proxy blind multi-signature scheme based on integer factorization problem (IFP) and discrete logarithm problem (DLP) to improve the security aspect. It satisfies the security properties of both the blind signature and the proxy multi-signature scheme

Performance Evaluation of Direct Torque Control with Permanent Magnet Synchronous Motor

The direct torque control theory has achieved great success in the control of permanent magnet synchronous motor. A Direct Torque Control (DTC) scheme of Permanent Magnet Synchronous Motor (PMSM) is presented. Based on in-depth analysis of PMSM mathematical model in abc frame and frame are established and the operation principle of DTC-SVPWM system, the relationships between the torque and fundamental components. A novel space vector pulse width modulation (SVPWM) method which has a feature of low harmonic is proposed. The proposed method is adopted to implement the direct torque control (DTC) of a three-phase PMSM. A large number of simulation results show that the DTC System of PMSM has fast response and good dynamic performance. Aiming at the direct torque control in PMSM Drives, in this paper explained the theoretical basis of the direct torque control (DTC) for PMSM firstly. Then explained the difference between the applications of DTC-SVPWM to PMSM. Finally the MATLAB/Simulink models were developed to examine the DTC- SVPWM for PMSM. The simulation results is presented in this paper

Characterization of Voltage Sags and its Mitigation Using Custom Power Devices in Emerging Power System

Voltage sags are short duration reductions in RMS voltage caused by short circuits, overloads and starting of large motors. Voltage sag is much more of a global problem. For proper analysis and mitigation of voltage sag, their characterization is important. The magnitude and durations are main characteristics of voltage sag. In this paper voltage sag and their characteristics have been presented in a comprehensive way. How voltage sags occur, what are their characteristics and impact on equipments behavior for different conditions. Through voltage source converters, it is possible to compensate for the drop in system voltage or even to temporarily take over the supply completely. The shunt and series controllers are based on power-electronic voltage source converters. For a full compensation both reactive and active power are needed. Only not for deep voltage sags but it is possible to compensate the drop in voltage magnitude by injecting reactive power only

CDMA2000 Past, Present and Future

The article looked into the possible future of 3GPP2s CDMA2000 1X and CDMA2000 1xEV-DO networks. The 3G CDMA2000 family of standards including EV-DO (Evolution Data Optimized) is in the daily use of more than 600 million customers across the globe. During the last few years the development efforts around CDMA2000 had been declined and its importance had been overshadowed by more advanced 3GPP LTE and IEEE WiMAX mobile broadband technologies. Due to these reasons, CDMA2000 operators are looking for alternative migration paths. The article investigated multiple facets for the future of CDMA2000 industry and these aspects were covered both from research and operational perspectives. The article first focused on the short term interoperability challenges to LTE and WiMAX and provided some antidotes for addressing these hurdles. The key challenges that were investigated include spectrum planning, authentication and security, end-to-end QoS (Quality of Service), voice enablement and data service continuity. The investigation revealed that a new QoS mapping mechanism between EV-DO and WiMAX similar to the one shown in the article is required for smooth operation. The analysis further indicated that CSFB (Circuit Switched Fallback) and SVLTE (Simultaneous Voice and LTE) were two techniques which could be used to support CS voice on an LTE/CDMA network; however they had different inter-radio access technology interworking requirements. In the following section performance aspects of both WiMAX and EV-DO were highlighted indicating a deep dip in throughput values once the users switches from WiMAX to EV-DO. The article concluded by discussing the future roadmap of CDMA2000 from 1X Advanced and DO Advanced perspectives. A performance comparison between 1X and 1X Advanced and EV-DO and DO Advanced was also presented

Should copper cables be phased out in the last mile?

It is commonly held by industry and government that copper cable should be phased out in favor of an all fiber network or wireless. Conversely, fiber optics has been in use for decades without displacing copper based networks. Additionally, copper is still being deployed for broadband services. This raises the following fundamental question: Is there a place for copper cabling in providing broadband solutions in the near and far term?this paper develop comprehensive distinctions between twisted pair copper and alternatives for current and future broadband solutions while rebutting arguments for transitioning to all fiber networks. It also compares fixed solutions against wireless alternatives, and present new technologies that drive continued value of copper conductors in the outside plant. Present personal experiences as well as those from industry professionals on the unique benefits that copper solution has which cannot be replicated by fiber will be shared for the benefit of educating the audiences.The results will show great potential for continued use of twisted pair copper in broadband networks. In the process, it will prove that current socio-political thinking promoting all-fiber broadband networks is flawed.Finally, it will be showed how copper will maintain a complementary role to fiber and wireless technologies as world-wide broadband networks continue to be built out

Fuzzy Based Gain Scheduled PI Controller for an Isolated Wind Diesel Hybrid Power System

Electrical power is the vital input for the economic development of any developing country. At their zenith, many excellent methods for the generation of power have been developed. The cost of supplying electrical power through grid to rural areas is becoming excessively high due to large investments in transmission and distribution lines, centralized power generating stations and line losses. For these reasons, the stand alone decentralized power generating stations with non– conventional energy sources like wind, biomass, solar energy, micro and mini hydel sources are being considered for electrifying remote rural areas. Hence in this paper an isolated wind–diesel hybrid power system with superconducting magnetic energy storage unit is considered. The hybrid power system is normally equipped with a control system, which functions to reduce the system frequency oscillations and makes the wind turbine generator power output follow the performance curve when the system is subjected to wind/load disturbances. Usually PI controllers are employed in these systems. Unfortunately, since the operating point continuously changes depending on the demand of consumers, this constant gain PI controller are unsuitable to other operating points. Therefore, this paper describes the application of the fuzzy gain scheduling on the PI controller for an isolated wind – diesel hybrid power system with superconducting magnetic energy storage unit

Design And Implementation Of Error Correcting Codes For Transmission in Binary Symmetric Channel

Error Correcting codes are normally used for protecting transmitted information bits in a noisy channel. The information bits are encoded into error correcting codes which will be transmitted into the channel and on the receiver side, the received codes will be decoded back into the transmitted information bits. In this paper, a technique of generating binary error correcting codes that meet the Gilbert-bound and a simple encoding-decoding mechanism will be presented. To show the performance of the error correcting codes, a Binary Symmetric Channel is considered for transmission

Efficient Three Party Key Exchange Protocol

Key exchange protocols allow two or more parties communicating over a public network to establish a common secret key called a session key. In 1976, Diffie and Hellman proposed the first practical key exchange (DH key exchange) protocol.  In 2005, Abdalla and  Pointcheval suggested  a new variation  of the computational   DH assumption  called chosen based computational Diffie Hellman (CCDH)  and presented  simple password based authenticated  key exchange protocols.  Since then several three party password  authenticated key agreement  protocols  have  been proposed  In 2007, Lu and  Cao proposed  a simple 3 party authenticated  key exchange  (S-3PAKE)  protocol.  Kim   and  Koi found  that this protocol cannot  resist  undetectable   online password  guessing attack  and gave fixed STPKE’ protocol as a countermeasure  using exclusive-or operation.  Recently,   Tallapally and Padmavathy found that STPKE’ is still vulnerable to undetectable online password guessing attack and gave a modified STPKE’ protocol.  Unfortunately,   we find that, although  modified STPKE’ protocol  can  resist  undetectable   online  password  guessing  attack   but it is vulnerable  to man  in the middle  attack.  Also, we propose and analyze an efficient protocol against all the known attacks