Mashkuri Yaacob

Effect of modulation index of pulse width modulation inverter on total harmonic distortion for sinusoidal

Knowing Total Harmonic Distortion (THD) content of voltage source inverter (VSI) is important and must be within the allowable range. Several schemes are suggested to mitigate THD and to produce as much a sinusoidal output signal as would be possible. One of such schemes is using a Sinusoidal Pulse Width Modulation SPWM-based inverter. SPWM is usually used in inverters for industrial applications. In this paper, a study of the performance of the SPWM technique is presented for a single phase H-bridge inverter. The SPWM scheme is modeled in MATLAB - Simulink. A bipolar and unipolar PWM technique are compared in this project as such techniques offer the features of effectively doubling the switching frequency of the output voltage. Under different conditions of modulation index, the pattern is utilized to estimate the harmonics. Simulation results for a full bridge single phase inverter using bipolar and unipolar SPWM schemes are presented.

Application of UWB wireless MIMO connectivity inside modern aircraft

Monitoring a large number of interacting sensors, actuators and controllers in sensitive locations simultaneously, requires efficient and fast network. Sophisticated computer controlled systems in modern aircrafts have become a necessity. Wired connectivity can be both awkward and hazardous. In this paper we propose wireless connectivity based on Impulse-Radio Ultra Wideband (IR-UWB) system. It is a promising technology for the exchange of high data rates in a limited space. It acts like a Personal Local Area Network (PLAN) suitable for limited space within an aircraft. The proposed scheme utilizes the novel pulse generator developed in these laboratories. The pulse shapes comply with the FCC regulations regarding power levels and spectral mask limitations. It mitigates interference effects with narrowband systems. The proposed scheme has been analyzed theoretically and implemented practically giving sound results. It has so far proved to be an excellent short-range communication technology in terms of cost, speed, power consumption and capacity. A practical system is designed and built, which is capable of operating in the Gbps range. The proposal is anticipated to open possibilities for further applications such as ships, control towers operating theaters, and any other application where a large number of peripherals are in interaction simultaneously. The UWB pulse generator produces pulses, which are portions of simple monocycle sine wave shapes in the GHz range. Results obtained through simulation and theoretical analysis show excellent and constant agreement with results obtained by experimental measurements.

Stepped Waveform Generation for Multilevel Inverter Topology Applications

This paper presents a review of the various inverter topologies, showing their utility in generating stepped waveform. The role of the PWM is highlighted in the operation of inverter for generating stepped-wave forms. The results show how similarly generated PWM used by different topologies can result into a stepped-waveform output capable of producing and AC closer to single fundamental component of 50Hz. The total harmonic Distortion (THD) is given for each set of simulation result with a relatively marked, though marginal utility, of the PWM used.

Recognition of Metal Objects inside Wall using Antipodal Vivaldi Antenna

Received Dec 04, 2017 Revised Jan 11, 2018 Accepted Apr 15, 2018 Wireless Body Area Networks (WBANs) are fundamental technology in health care that permits the information of a patient’s essential body parameters to be gathered by the sensors. However, the safety and concealment defense of the gathered information is a key uncertain problem. A Hybrid Key Management (HKM) scheme [13] is worked based on Public Key Cryptography (PKC)-authentication scheme. This scheme uses a oneway hash function to construct a Merkle Tree. The PKC method increase the computational complexity and lacking scalability. Additionally, it increases expensive computation, communication costs and delay. To overcome this problem, Robust Security for Protected Health Information by ECC with signature Hash Function in WBAN (RSP) is proposed. The system employs hash-chain based key signature technique to achieve efficient, secure transmission from sensor to user in WBAN. Moreover, Elliptical Curve Cryptography algorithm is used to verifies the authenticate sensor. In addition, it describes the experimental results of the proposed system demonstrate the efficient data communication in a network.A Weblogs contains the history of User Navigation Pattern while user accessing the websites. The user navigation pattern can be analyzed based on the previous user navigation that is stored in weblog. The weblog comprises of various entries like IP address, status code and number of bytes transferred, categories and time stamp. The user interest can be classified based on categories and attributes and it is helpful in identifying user behavior. The aim of the research is to identifying the interested user behavior and not interested user behavior based on classification. The process of identifying user interest, it consists of Modified Span Algorithm and Personalization Algorithm based on the classification algorithm user prediction can be analyzed. The research work explores to analyze user prediction behavior based on user personalization that is captured from weblogs.Wireless Body Area Networks (WBANs) are fundamental technology in health care that permits the information of a patient’s essential body parameters to be gathered by the sensors. However, the safety and concealment defense of the gathered information is a key uncertain problem. A Hybrid Key Management (HKM) scheme [13] is worked based on Public Key Cryptography (PKC)-authentication scheme. This scheme uses a oneway hash function to construct a Merkle Tree. The PKC method increase the computational complexity and lacking scalability. Additionally, it increases expensive computation, communication costs and delay. To overcome this problem, Robust Security for Protected Health Information by ECC with signature Hash Function in WBAN (RSP) is proposed. The system employs hash-chain based key signature technique to achieve efficient, secure transmission from sensor to user in WBAN. Moreover, Elliptical Curve Cryptography algorithm is used to verifies the authenticate sensor. In addition, it describes the experimental results of the proposed system demonstrate the efficient data communication in a network.

An efficient cache replacement algorithm for minimizing the error rate in L2-STT-MRAM caches

In the recent times, various challenges are being encountered during SRAM cache design and development which lead to a situation of converting the memory cell technologies into on-chip embedded caches. The current research statistics towards cache designing reveals that Spin Torque Transfer Magnetic RAMs, preferably termed as STT-MRAMs has become one of the most promising areas in the field of memory chip design. Hence, it gained a lot of attention from the researchers due to its dynamic direct map and data access policies for reducing the average cost i.e. time and energy optimization. Instead of having efficient main memory access capability, STT-MRAMs suffer due to high error rate caused during stochastic switching in write operations. Cache replacement algorithms play a significant role in minimizing the error rate in write operations. The proposed study aims to offer a theoretical and analytical modeling of an efficient cache replacement scheme to overcome the error as mentioned above in L2-STT-MRAM caches. The performance analysis of the proposed algorithm ensures its effectiveness in reducing the error rate and cost overheads as compared to the conventional LRU technique implemented on SRAM cells.

A study on performance evaluation of conventional cache replacement algorithms: A review

Cache Replacement Policies play a significant and contributory role in the context of determining the effectiveness of cache memory cells. It has also become one of the major key features for efficient memory management from the technological aspect. Hence, owing to the existing critical computing systems, it has become too essential to attain faster processing of executable instructions under any adverse situations. In the current scenario, the state of art processors such as Intel multi-core processors for application specific integrated circuits, usually employ various cache replacement policies such as Least Recently Used (LRU) and Pseudo LRU (pLRU), Round Robin, etc. However, fewer amounts of existing research works are found till date to utter about explicit performance issues associated with the conventional cache replacement algorithms. Therefore, the proposed study intended to carry out a performance evaluation to explore the design space of conventional cache replacement policies under SPEC CPU2000 benchmark suite. It initiates and configures the experimental Simple Scalar toolbox prototype on a wide range of cache sizes. The experimental outcomes obtained from the benchmark suite show that PLRU outperforms the conventional LRU concerning computational complexity and a variety of cache blocks organization.