63 research outputs found
Design and development of non-isolated modified SEPIC DC-DC converter topology for high-step-up applications: Investigation and hardware implementation
No full textA new non-isolated modified SEPIC front-end dc-dc converter for the low power system is proposed in this paper, and this converter is the next level of the traditional SEPIC converter with additional devices, such as two diodes and splitting of the output capacitor into two equal parts. The circuit topology proposed in this paper is formulated by combining the boost structure with the traditional SEPIC converter. Therefore, the proposed converter has the benefit of the SEPIC converter, such as continuous input current. The proposed circuit structure also improves the features, such as high voltage gain and high conversion efficiency. The converter comprises one MOSFET switch, one coupled inductor, three diodes, and two capacitors, including the output capacitor. The converter effectively recovers the leakage energy of the coupled inductor through the passive clamp circuit. The operation of the proposed converter is explained in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The required voltage gain of the converter can be acquired by adjusting the coupled inductor turn’s ratio along with the additional devices at less duty cycle of the switch. The simulation of the proposed converter under CCM is carried out, and an experimental prototype of 100 W, 25 V/200 V is made, and the experimental outcomes are presented to validate the theoretical discussions of the proposed converter. The operating performance of the proposed converter is compared with the converters discussed in the literature. The proposed converter can be extended by connecting voltage multiplier (VM) cell circuits to get the ultra-high voltage gain
MOMPA: Multi-objective marine predator algorithm for solving multi-objective optimization problems
No full textThis paper proposes a new multi-objective algorithm, called Multi-Objective Marine-Predator Algorithm (MOMPA), dependent on elitist non-dominated sorting and crowding distance mechanism. The proposed algorithm is based on the recently proposed Marine-Predator Algorithm, and it was inspired by biological interaction between predator and prey. The proposed MOMPA can address multiple and conflicting objectives when solving optimization problems. The MOMPA is formulated using elitist non-dominated sorting and crowding distance mechanisms. The proposed method is tested on various multi-objective case studies, including 32 unconstrained, constraint, and engineering design problems with different linear, nonlinear, continuous, and discrete characteristics-based Pareto front problems. The results of the proposed MOMPA are compared with several well-regarded Multi-Objective Water-Cycle Algorithm, Multi-Objective Symbiotic-Organism Search, Multi-Objective Moth-Flame Optimizer algorithms qualitatively and quantitatively using several performance indicators. The experimental results demonstrate the merits of the proposed method.No Full Tex
Comparative analysis of recent metaheuristic algorithms for maximum power point tracking of solar photovoltaic systems under partial shading conditions
No full textThe photovoltaic (PV) system comprises one or more solar panels, a converter/inverter, controllers, and other mechanical and electrical elements that utilize the generated electrical energy by the PV modules. The PV systems are ranged from small roofs or transportable units to massive electric utility plants. The maximum power point tracking (MPPT) controller has been used in PV systems to get the maximum power available. In addition, the MPPT controller is much essential for PV systems to protect the battery devices or direct loads from the power fluctuations received from solar PV panels. There are several MPPT control mechanisms available right now. The most common and commonly applied approaches under constant irradiance are perturb and observe (P&O) and incremental conductance (INC). But such methods show variations in the maximum power point. In this sense, this paper analyses and utilizes two recent metaheuristic algorithms called artificial rabbit optimization (ARO) and the most valuable player (MVP) algorithm for MPPT applications. The performance comparisons are made with the most preferred traditional algorithms, such as P&O and INC. Based on the result obtained, this study recommends that ARO perform better in standard testing conditions than all the other algorithms, but in partially shaded conditions, the MVP algorithm performs better in terms of efficiency and tracking speed
Voltage Regulation on High PV penetrated Distribution system using Electric Vehicles
No full textThe penetration of renewable energy sources is increasing every year and that poses a lot of challenges in the distribution system. Since they are intermittent in nature, they cannot serve the energy demand as stand alone sources without the help of storage technologies or stable energy sources. As the RES, especially the Photo Voltaic generation units are often connected in the distribution system, their intermittent nature may result in a sudden rise or fall in overall generation. Hence the voltage has to be kept within limits to prevent the failure of the system. Storage technologies plays an important role in keeping the voltage levels under control. From the consumer perspective, the usage of electric vehicles is steadily increasing and most of the vehicles are connected to public charging stations to charge the vehicle battery. Hence there is an interaction between the EVs and distribution grids, which is utilized as a storage option here. In this research, the voltage changes due to the penetration of renewable energy sources in the distribution system is regulated by using the electric vehicles as a storage option. This thesis tries to give an understanding on the strategy applied towards regulation of voltage in the distribution system using electric vehicles. The strategy will serve as a platform for regulating voltage using electric vehicles and it can be adapted to any such distribution network. This strategy takes into account the size and capacity of the battery, battery state of charge and the availability of electric vehicles for a given day. Consensus algorithm serves as the communication platform for information interchange between the electric vehicles connected in the network. Average consensus algorithm estimates the average state of charge of the electric vehicles connected in the distributed network and that has been used to ensure equitable contribution of power among the electric vehicles. Markov model is used to simulate the travel pattern of the electric vehicles. This provides a more realistic and accurate pattern of travel. Markov model is implemented with and without considering time of occurrence and the results shows that the pattern is more accurate when time is considered as a parameter. Considering the generated travel pattern, voltage level of the buses in the network and the output from the consensus algorithm, the voltage has been regulated. The Electric vehicles are used for regulating the voltage when the voltage level is beyond the tolerance limits, and during other times, the electric vehicles charge their batteries. This is executed by controlling the charging and discharging cycles of the electric vehicles. The results are discussed based on different cases and the advantages and limitations of each case is explained in detail. The simulation is not robust since the availability of electric vehicles is uncertain. To make it more robust, monte carlo simulations are used. The probability of occurrence of several events has been estimated using monte carlo simulations and through the results, the availability is predicted to a certain extent. Different cases are implemented and analysed and the results shows that the availability depends on the bus, the location of the bus and the travel behaviour of the electric vehicles. Each case is discussed separately and the degree of uncertainty is reduced at the end.Electrical Engineering | Sustainable Energy Technolog
New Initiative: The Naturalness of Software
No full textAbstract—This paper describes a new research consortium, studying the Naturalness of Software. This initiative is supported by a pair of grants by the US National Science Foundation, totaling 600,000 helped kickstart an inter-disciplinary effort, and demonstrate feasibility; a follow-on full grant of $2,000,000 was recently awarded. The initiative is led by the author, who is at UC Davis, and includes investigators from Iowa State University and Carnegie-Mellon University (Language Technologies Institute). I
Evaluation of low-temperature properties of Asphalt Binders and mixtures
No full textBecause of the widespread use of modifiers and additives in asphalt bitumen, this study revisits and evaluates the adaptation of the time-temperature superposition principle that is incorporated into the low-temperature Superpave® binder specifications. The study builds on results of bending beam rheometer (BBR) tests conducted on samples of asphalt binders used in seven different surface layer mixtures. Both 240-s and 2-h BBR tests were conducted at three different temperatures: the low temperature of the asphalt performance grade (TL), 10 C higher than the low-temperature grade (TL- sub+10), and at -5 C to construct the flexural creep stiffness master curves. Additionally, indirect tensile tests were conducted on the surface layer mixtures to determine the low-temperature properties. The BBR test results show that the methodology adopted in using the equivalence principle to formulate the low-temperature Superpave binder specifications does not accurately apply for some of the binders used in this study. Thus, modifications to the specifications for loading times and test temperatures are suggested. Further, the time-temperature shift factors for the binders evaluated are compared with the universal shift factors used in the SHRP study. The observed mismatch in the shift factor sets is in disagreement with the implicit assumption that all asphalt binders can be characterized by similar shift factors at low temperatures. The shift factors of the binders and mixtures used in this study tend to match well, particularly at high testing temperatures.Anderson D. A., 1994, A367 SHRP TRB NAT RE, V1; Anderson D. A., 1994, A369 SHRP TRB NAT RE, P3; Anderson D. A., 1990, ARD88078 FHWA US DEP; Asphalt Institute, 1996, SUP MIX DES; Bahia H. U., 1993, STP ASTM, V1241, P28; Bahia HU, 1992, P ASS ASPHALT PAVING, V61, P117; Bahia H.U., 1991, THESIS PENNSYLVANIA; Basu A, 2003, TRANSPORT RES REC, P1; Buttlar W. G., 1996, THESIS PENNSYLVANIA; Marasteanu MO, 2000, TRANSPORT RES REC, P1; McLeod N. W., 1968, P 13 ANN C CAN TECHN; Readshaw E.E., 1972, J ASS ASPHALT PAVING, V41, P562; Wen H., 2001, THESIS N CAR STAT U0
Mobile phone application : recording on going phone conversations in mobile phones
No full textPreviously, call recording applications were common in mobile operating system such as Symbian. As technology advances rapidly, Symbian is slowly being phased out. Currently, modern mobile operating system starts to take the place of Symbian. The most commonly used mobile operating systems currently are Apple iOS and Google Android.
However, there are currently limited applications on mobile phones using modern operating system such as iOS and Android that record phone conversation. Having an application that is able to record phone conversation will be useful in many ways. Firstly, these recorded conversations are useful in verification and forensic analysis which can be used in court. Secondly, it can also be used by journalist to record their phone interview with the other party. Thirdly, it can be used in businesses whereby the seller cannot deny something that has been agreed upon. Fourthly, it can also be used as evidence against any sort of harassment on the phone and lastly, during instances when you do not have a pen and your friend is telling you the direction on where to go or the phone number that you should call.
An application that record voice calls for Android is proposed. Android programming was intensively studied to allow the author to program for Android phones. Then, research work was done on how to program the application and at what point does the application start to enable the user to record effectively. The application named Call Recorder was developed and it worked as desired.
The report illustrates some literature review of Android, how the application works and also some ways to improve on the application. Bachelor of Engineering (Computer Engineering
Data from 617 healthy participants performing the Iowa gambling task: a "many labs" collaboration
No full textThis data pool (N = 617) comes from 10 independent studies assessing performance of healthy participants (i.e., no known neurological impairments) on the Iowa gambling task (IGT) - a task measuring decision making under uncertainty in an experimental context. Participants completed a computerized version of the IGT consisting of 95 - 150 trials. The data consist of the choices of each participant on each trial, and the resulting rewards and losses. The data are stored as .rdata, .csv, and .txt files, and can be reused to (1) analyze IGT performance of healthy participants; (2) create a "super control group"; or (3) facilitate model-comparison efforts
Resistance–capacitance optimizer: a physics-inspired population-based algorithm for numerical and industrial engineering computation problems
No full textAbstract The primary objective of this study is to delve into the application and validation of the Resistance Capacitance Optimization Algorithm (RCOA)—a new, physics-inspired metaheuristic optimization algorithm. The RCOA, intriguingly inspired by the time response of a resistance–capacitance circuit to a sudden voltage fluctuation, has been earmarked for solving complex numerical and engineering design optimization problems. Uniquely, the RCOA operates without any control/tunable parameters. In the first phase of this study, we evaluated the RCOA's credibility and functionality by deploying it on a set of 23 benchmark test functions. This was followed by thoroughly examining its application in eight distinct constrained engineering design optimization scenarios. This methodical approach was undertaken to dissect and understand the algorithm's exploration and exploitation phases, leveraging standard benchmark functions as the yardstick. The principal findings underline the significant effectiveness of the RCOA, especially when contrasted against various state-of-the-art algorithms in the field. Beyond its apparent superiority, the RCOA was put through rigorous statistical non-parametric testing, further endorsing its reliability as an innovative tool for handling complex engineering design problems. The conclusion of this research underscores the RCOA's strong performance in terms of reliability and precision, particularly in tackling constrained engineering design optimization challenges. This statement, derived from the systematic study, strengthens RCOA's position as a potentially transformative tool in the mathematical optimization landscape. It also paves the way for further exploration and adaptation of physics-inspired algorithms in the broader realm of optimization problems
- …
