Sudden Load Increase Research Articles

Comparison of support strategies for grid construction after failure of renewable energy power generation system

As the proportion of renewable energy generation continues to rise, the study of voltage source converter (VSC) control has become a focal point of research. The concepts of emulating the characteristics of synchronous machines have led to the proposals of droop control and virtual synchronous control (VSG). However, a deeper comparison of the control characteristics of these two methods is still needed, particularly in terms of their ability to support the system when partial power sources experience fault conditions. This paper analyzes and compares the two in terms of control principles and small-signal modeling, and finally, based on a nine-bus system with 100% renewable energy generation, two scenarios are designed: a sudden load increase and a partial power source disconnection. The differences in control characteristics between the two are compared and analyzed. The results indicate that the VSG exhibits greater damping compared to droop control and is capable of providing inertial support to the system, making its frequency and voltage less susceptible to change.

Active Disturbance Rejection Control for Flux Weakening in Interior Permanent Magnet Synchronous Motor Based on Full Speed Range

To address the impact of load disturbances on the full-speed-range control of an interior permanent magnet synchronous motor (PMSM), an active disturbance rejection control (ADRC) method is proposed. The speed loop employs phased field-weakening control (FW) based on ADRC, while the current loop utilizes proportional-integral-derivative (PID) control. Starting from the motor parameters, the Lagrange multiplier method was used to derive the critical speeds for the maximum torque per ampere (MTPA) and maximum torque per voltage (MTPV) ratios, and the timing for the field-weakening control was analyzed. A full-speed-range control model of the motor was established, and an ADRC-based speed loop controller was designed to achieve smooth transitions between high speeds and anti-disturbance solid capabilities. Based on the proposed control strategy, a 21 kW PMSM was used as the research object, and a full-speed-range control simulation model was developed in MATLAB/SIMULINK to verify the strategy. Compared to the traditional PID control, the simulation results demonstrate that the proposed strategy effectively observes and compensates for load disturbances, significantly reducing initial torque oscillations under three different operating conditions. After a sudden load increase, torque oscillations were reduced by 16%, with the stator current reaching steady state 0.03 s faster, response speed improving by 0.02 s, smooth transitions between speed ranges, and enhanced anti-disturbance performance.

Oxygen-sensor-based 2-DOF PI air-flow controller of fuel cell system

Oxygen starvation may occur when oxygen is not replenished quickly after a sudden increase of load in fuel-cell-powered vehicles, leading to permanent damage to the fuel cell membrane. To avoid this phenomenon, the oxygen excess ratio (OER) is usually estimated through observers as it cannot be measured directly. Since observers may suffer from model mismatches that lead to inaccurate OER estimation, a possible modification to the fuel cell system is proposed in this work by including an oxygen flow sensor at its exhaust. Yet the response of this sensor is slow, and to compensate for the slow response of the sensor, a novel two-degree-of-freedom PI controller and a state observer are designed to provide a robust, accurate, and quick estimation and control of the OER.

Mechanical load regulates the proliferation of multiple cell types in the heart

Abstract Funding Acknowledgements None. Introduction The adult mammalian heart has a poor regenerative and angiogenic potential. At the same time, both primary cardiac tumors and cardiac metastases are extremely rare. This suggests that shared mechanisms may halt the proliferation of cardiac (both cardiomyocyte and endothelial) and cancer cells. Among the mechanisms that have been claimed to be responsible for the loss of proliferative potential of cardiomyocytes early after birth is a sudden increase in mechanical load. Purpose Here, we investigate whether alterations in mechanical load affect the proliferation of multiple cell types in the heart. Methods Adult heart unloading in vivo was achieved using a mouse model of heterotopic heart transplantation, followed by EdU injection to label proliferating cells. Engineered heart tissues (EHTs) were generated using neonatal cardiomyocytes and fibroblasts, with a modified protocol allowing to finely tune mechanical load. Primary cardiac endothelial cells and multiple types of cancer cells (lung, melanoma and colon cancer) along with adult cardiac endothelial cells were included in EHTs. Results In line with our hypothesis, unloaded, heterotransplanted hearts showed a significant number of proliferating cardiomyocytes and endothelial cells, which were almost absent in native hearts. While cancer cells did not grow in native hearts, they massively proliferated in unloaded hearts. Consistent with in vivo results, mechanical unloading in EHTs significantly increased the percentage of EdU-positive cardiomyocytes, endothelial and cancer cells. In contrast, increasing afterload reduced cell proliferation in all cell types. Mechanistically, we identified Nesprin2 as an essential factor in sensing mechanical load and translating it into a cell proliferation arrest. Conclusions Overall, these data indicate that variations in mechanical load have a dramatic effect on the proliferation of multiple cell types within the heart tissue, including cardiomyocytes, endothelial and cancer cells and that Nesprin2 is required to mediate this effect.Unloading in the heartUnloading in EHT

Composite ADRC Speed Control Method Based on LTDRO Feedforward Compensation.

The performance of the extended state observer (ESO) in an Active Disturbance Rejection Control (ADRC) is limited by the operational load in stepper motor control, which has high real-time requirements and may cause delays. Additionally, the complexity of parameter tuning, especially in high-order systems, further limits the ESO's performance. This paper proposes a composite ADRC (LTDRO-ADRC) based on a load torque dimensionality reduction observer (LTDRO). Firstly, the LTDRO is designed to estimate abrupt load disturbances that are difficult to compensate for using the ESO. Secondly, the transfer function under the double-closed loop is deduced. Additionally, the LTDRO uses a magnetic encoder to gather the system state and calculate the load torque. It then outputs a compensating current feedforward to the current loop input. This method reduces the delay and complexity of the ESO, improving the response speed of the ADRC speed ring and the overall response of the system to load changes. Simulation and experimental results demonstrate that it significantly enhances dynamic control performance and steady-state errors. LTDRO-ADRC can stabilize the speed again within 49 ms and 17 ms, respectively, in the face of sudden load increase and sudden load removal. At the same time, in terms of steady-state error, compared with ADRC and CADRC, they have increased by 94% and 88%, respectively. In terms of zero-speed starting motors, the response speed is increased by 58% compared to a traditional ADRC.

Supercapacitor Implementation To Prototype Energy Storage System Optimizer in PV System

This research aims to create a prototype of an energy storage optimizer in a PV system using a supercapacitor in combination with batteries. The purpose of adding supercapacitors in this prototype is to maintain battery usage when there is a change in irradiation with a loading source that refers to the amount of electrical current and voltage as a supply of energy. A sudden increase in load without an energy buffer component can affect battery endurance. This can result in a decrease in electrical energy supply. Based on experimental results, it has been found that the battery and supercapacitor complement each other. The battery works more statically while the supercapacitor works more dynamically. Thus, the power output to the load is more stable, and the battery can be more durable because when there are extreme changes in irradiation and load, they can be overcome by supercapacitors.

Design of an energy management system applied to an electric power plant based on a biomass gasifier

Biomass gasification plants for electricity generation are an environmentally friendly technology. One of their main problems is their poor responsiveness to load variations when the plant operates off-grid. For this reason, they are usually grid-connected systems.Therefore, as a solution, an energy management system that allows the plant to operate off-grid is proposed. The system has been obtained through the optimal design of unidirectional and bidirectional Z-source converters and their coupling with their series outputs. This approach has been applied to a biomass gasification power plant.To validate the system, the results of an experimental 10 kW gasification plant are presented. With the plant working off-grid, there is a sudden load increase of 2.5 kW, and due to the proposed system performance, there is only an output voltage oscillation of less than 1%, preserving a stable power supply.This proposed system allows the plant to work isolated or coupled to a weak micro-grid of renewable energies. Obtaining a permanent supply of quality and also improving its efficiency. Thus, the gasification technology can be used for electricity generation in isolated areas of many developing countries, where the electrical grid is not totally developed, but there are available biomass sources.

Transient power equalization control strategy of virtual synchronous generator in isolated island microgrid with heterogeneous power supply

In the parallel supply system of synchronous generator and virtual synchronous generator, the physical structure and control structure of the two kinds of power supply are quite different, and it is difficult to distribute the transient power of the two kinds of power supply evenly when the load changes abruptly. Especially in the case of sudden load increase, virtual synchronous generator bears too much load in the transient process because of its fast adjustment speed, and even causes short-term overload, which makes the capacity of virtual synchronous generator can not be fully utilized. In view of this problem, firstly, the mechanism of transient power uneven distribution of two heterogeneous power sources is explained from the differences of frequency modulation, voltage regulation and output impedance. Secondly, virtual speed regulation, virtual excitation and dynamic virtual impedance are added to the traditional virtual synchronous generator control to simulate the speed regulation characteristics and electromagnetic transient characteristics of the synchronous generator, so as to realize the transient and steady-state power equalization between heterogeneous power supplies when the virtual synchronous generator and the synchronous generator run in parallel. Thirdly, in order to ensure the fast dynamic response characteristics of the virtual synchronous generator in independent operation mode, the traditional virtual synchronous generator control algorithm is still maintained in independent operation mode, and the mode switching control link based on state tracking is designed to realize smooth switching between the two working modes. Finally, the hardware in loop experiment results based on RT-LAB show that the proposed control method can realize the transient and steady-state power equalization when the virtual synchronous generator and the synchronous generator operate in parallel, it can keep the fast voltage regulation and frequency modulation ability when the virtual synchronous generator operates independently, and can realize smooth switching between independent and parallel operation modes.

Overview of Various Voltage Control Technologies for Wind Turbines and AC/DC Connection Systems

Wind power generation is one of the mainstream renewable energy resources. Voltage stability is as important as the frequency stability of a power system with a high penetration of wind power generation. The advantages of high-voltage direct current (HVDC) transmission systems become more significant with the increase of both installed capacity and transmission distance in offshore wind farms. Therefore, this study discusses various voltage control methods for wind turbines and HVDC transmission systems. First, various voltage control methods of a wind farm were introduced, and they include QV control and voltage droop control. The reactive power of a wind turbine varies with active power, while the active power from each wind turbine may be different owing to wake effects. Thus, QV and voltage droop control with varying gain values are also discussed in this paper. Next, the voltage control methods for an HVDC transmission system, such as power factor control, voltage control, and Vac-Q control, are also summarized and tested in this study. When a three-phase short circuit fault occurs or a sudden reactive power load increases, the system voltage would drop immediately. Thus, various voltage control methods for wind turbines or HVDC can make the system’s transient response more stable. Therefore, this study implemented the simulation scenarios, including a three-phase short circuit fault at the point of common coupling (PCC) or a sudden increase of reactive power load, and adopted various voltage control methods, which aim to verify whether additional voltage control methods are effective to improve the performance of transient voltage. The voltage control method has been implemented in PSCAD/EMTDC, and the simulation results show that the QV control performs better than the droop control. In addition, when applying the voltage control technique during a three-phase fault, transient voltage nadir can be improved through either an HVDC transmission system or an AC transmission system.

Guidelines for Voltage Controller Coefficients Design to Attain Prescribed Grid Current THD and DC-Link Voltage Undershoot Values in Power Factor Correction Front Ends

This article establishes analytical guidelines for designing coefficients of proportional integral (PI) controller, typically used as voltage loop compensator of power factor correction rectifiers (PFCRs) operating in continuous conduction mode (CCM), based on two major performance merits (namely, total harmonic distortion (THD) of grid-side current and dc-link voltage deviation upon sudden load increase) and dc-link capacitance-to-rated power ratio. The proposed methodology allows to concretize the commonly used “5–10 Hz crossover frequency, 45°–70° phase margin” rule-of-thumb, typically used in application notes of commercial PFCR controllers. Explicit relationships between voltage loop gain crossover frequency and phase margin as well as settling time of dc-link voltage response to a step load increase to the above-mentioned performance merits are also derived in this article. Provided design guidelines allow to accurately achieve desired values of the two mentioned performance merits and indicate the feasible range of possible dc-link capacitance values. The proposed quantitative design guidelines are well-supported by experiments.

Bearing Aluminum-Based Alloys: Microstructure, Mechanical Characterizations, and Experiment-Based Modeling Approach.

Due to the engine's start/stop system and a sudden increase in speed or load, the development of alloys suitable for engine bearings requires excellent tribological properties and high mechanical properties. Including additional elements in the Al-rich matrix of these anti-friction alloys should strengthen their tribological properties. The novelty of this work is in constructing a suitable artificial neural network (ANN) architecture for highly accurate modeling and prediction of the mechanical properties of the bearing aluminum-based alloys and thus optimizing the chemical composition for high mechanical properties. In addition, the study points out the impact of soft and more solid phases on the mechanical properties of these alloys. For this purpose, a huge number of alloys (198 alloys) with different chemical compositions combined from Sn, Pb, Cu, Mg, Zn, Si, Ni, Bi, Ti, Mn, Fe, and Al) were cast, annealed, and tested for determining their mechanical properties. The annealed sample microstructure analysis revealed the formation of soft structural inclusions (Sn-rich, Sn-Pb, and Pb-Sn phases) and solid phase inclusions (strengthened phase, Al2Cu). The mechanical properties of ultimate tensile strength (σu), Brinell hardness (HB), and elongation to failure (δ) were used as control responses for constructing the ANN network. The constructed network was optimized by attempting different network architecture designs to reach minimal errors. Besides the excellent tribological characteristics of the designed set of alloys, soft inclusions based on Sn and Pb and solid-phase Cu inclusions fulfilled the necessary level of mechanical properties for anti-friction alloys; the maximum mechanical properties reached were: σu = 197 ± 7 MPa, HB = 77 ± 4, and δ = 20.3 ± 1.0%. The optimal ANN architecture with the lowest errors (correlation coefficient (R) = 0.94, root mean square error (RMSE) = 3.5, and average actual relative error (AARE) = 1.0%) had two hidden layers with 20 neurons. The model was validated by additional experiments, and the characteristics of the new alloys were accurately predicted with a low level of errors: R ≥ 0.97, RMSE = 1-2.65, and AARE ˂ 10%.

Relationship between training load and law enforcement recruit injuries during academy training

Introduction: Law enforcement is a profession interspersed with periods of high intensity, physically demanding occupational requirements such as chasing suspects. To prepare for this occupation, law enforcement agencies typically utilise training periods known as academies. These academies represent a sudden increase in physical training load, and mental stress. It is therefore unsurprising that these periods of training typically result in high rates of injury. The aim of this research was to assess the relationship between training load factors and injury risk in law enforcement recruits.

NEURO-FUZZY INTELLIGENT CONTROLLER FOR LFC OF A FOUR-AREA POWER SYSTEM

In modern complex power systems, the problem of automatic generation control arises due to a sudden increase or decrease in load. This problem leads to instability in the system if the frequency control is not automatic, which may finally lead to system collapse. Hence, automatic control of frequency and tie-line power is significant. This research paper develops and compares the performance of an adaptive neuro-fuzzy inference system (ANFIS) controller with the conventional PID controller and the Takagi-Sugeno-Kang fuzzy logic controller for load frequency control (LFC) of a four-area power system with generation rate constraint (GRC) on turbines. The performance is compared in terms of errors, settling time and maximum undershoot of the frequency deviation for different step load changes using Matlab. The proposed ANFIS controller performs with less peak undershoot of - 0.7374 Hz and a settling time of 27.9823 sec at a 4% change in load. It reduces the steady-state error to zero. Thus, the proposed controller is the most suitable LFC in energy centers. The system parameters are taken from the IEEE press, and EPRI published books.

Abstract P1003: Mechanical Loading Controls Cardiomyocyte Proliferation

Introduction: Mammal cardiomyocytes (CMs) lose their proliferative capacity early after birth and switch to an adult phenotype, characterized by organized sarcomeres. The mechanisms that control this switch remain largely elusive. Among the changes experienced by the heart at birth is a sudden increase in mechanical load. Hypothesis: This study tests the hypothesis that variations in mechanical loading may regulate both the proliferation and the maturation of cardiomyocytes. Methods: Engineered heart tissues (EHTs) were generated using neonatal rat heart cells, with a modified protocol allowing to alter mechanical load. Unloading is obtained by reducing the distance between the silicon posts that anchor the extremities of the EHT, while overloading is induced by changing Young’s module of posts using metal braces. Adult heart unloading in vivo was achieved by heterotopically transplanting a mouse heart into the neck of syngeneic recipient mice, which were injected with EdU twice per week. Both hearts, native and transplanted, were harvested at day 30. Results: In line with our hypothesis, mechanical unloading of developed EHTs significantly increased the percentage of EdU-, Ki67- and pH3-positive CMs at 72 hours. In contrast, increasing afterload induced CM maturation, characterized by increased cross-sectional area and force of contraction, associated with reduced proliferation. Consistently, heterotopically transplanted hearts showed a significant increase in the the number of proliferating CMs in both ventricles, which were almost absent in native hearts. Conclusions: Our data indicate that mechanical unloading induce CM proliferation in both rat EHTs and an in vivo in a mouse model of heterotopic heart transplantation. These results support our initial hypothesis and indicate that mechanical loading is a master regulator of cardiomyocytes proliferation and maturation. Ongoing experiments aim at identifying the molecular mechanisms that regulate this process.

An ANN based switching network for optimally selected photovoltaic array with battery and supercapacitor to mitigate the effect of intermittent solar irradiance

ABSTRACT Power fluctuation at the PV panel output is caused by variation of input irradiance. Several optimization techniques have been used for selecting the Global Maximum Power Point (GMPP) from different Local Maximum Power Point (LMPP) that are caused due to variable irradiance. Reconfiguring the PV array by various combination based on the available irradiance is used to overcome the effects of partial shading. In these methods, system complexity increases and efficiency reduces as the size of PV array increases. Hence, in this paper Artificial Neural Network (ANN) based switching network of optimum number of PV panel with battery and supercapacitor is formed. Genetic Algorithm (GA) is used to optimize the number of PV panels, battery and supercapacitor. Battery and supercapacitors are used as energy back up to support the load during low power generation from PV panels. Size of supercapacitors is calculated to support the system during instant power fluctuation caused either due to sudden increase in load or unexpected variation in irradiance. Power enhancement of optimized PV array is performed by ANN based switching and numerically analyzed, and compared with other reconfiguration methods. Optimization is carried out for a system having 245 kW load which led to 1281 number of PV panels, 161 number of batteries and 8 supercapacitors for minimum cost of energy sources. Results of optimization are used for switching of 1281 PV array to form 16 × 81 strings. Out of which 16 × 9 strings are selected for Month Ahead Scheduling (MAS) and string of 16 × 1 PV panels for Real Time Scheduling (RTS). Considering variations at the input irradiance while load is constant. For the selected value of irradiance 16 × 45 strings remain ON which is selected as the base value.

Vibration Characteristics of a Hydroelectric Generating System with Different Hydraulic-Mechanical-Electric Parameters in a Sudden Load Increasing Process

In a sudden load increasing process (SLIP), the hydroelectric generating system (HGS) experiences a severe vibration response due to the sudden change of the hydraulic-mechanical-electric parameters (HMEPs). The instability of HGS limits the ability of sudden load increase, and its flexibility and reliability are reduced. Thus, in this study, a new transient nonlinear coupling model of HGS is proposed, which couples the hydro-turbine governing system (HTGS) and the hydro-turbine generator shafting system (HGSS) with the hydraulic-mechanical-electric coupling force, rotating speed, flow rate, hydro-turbine torque, electromagnetic torque, and guide vane opening. By using numerical simulation, the influences of different HMEPs on the vibration characteristics of HGS in SLIP are analyzed. The result shows that, compared with stable operating conditions, the vibration amplitude of HGS increases sharply in SLIP. The increase of the sudden load increasing amount, blade exit flow angle, mass eccentricity and excitation current, and the decrease in guide bearing stiffness and average air gap between the stator and rotor cause abnormal vibration of different degrees in the HGS. Hydraulic factors have the greatest influence on the nonlinear dynamic behavior of HGS. The maximum vibration amplitude of HGS in SLIP is increased by 70.46%, compared with that under stable operating conditions. This study provides reasonable reference for the analysis of the nonlinear dynamic behavior of HGS in SLIP under the multiple vibration sources.

Air-flow control in fuel cells using delay-based load governor and feedforward augmented dynamic inversion

The frequent and sudden increase of load in electric vehicles depletes oxygen from the fuel cell cathode, leading possibly to oxygen starvation. This paper presents the design of an air flow controller for fuel cell systems (FCS) that aims to replenish the depleted oxygen. A dynamic inversion is used as the feed-forward compensation for the disturbance effect coming from the load current change. However, the inverted dynamics have negative relative degree (improper) and not physically realizable. To make it proper, an augmentation by delay is done, with the same delay added into demand current. The current-dependent time delay introduced in the demand current gives the FCS the opportunity to prepare a sufficient air flow that can withstand the dip in oxygen excess ratio (OER). Besides, the FCS plant is linearized at various operating points, and the dynamic feedforward controller is designed at several operating points with interpolation applied for in-between values. The simulation results show a considerable improvement in the OER response where the constraint is met and the recovery time is reduced.

Supervisory Controller Design for Power System Stability using Hybrid Automata Modeling

Power systems are categorized as nonlinear dynamical systems, and the importance and complexity associated with their stability have dramatically increased. Accordingly, the behavior of power systems can be characterized by interactions between continuous and discrete-event dynamics. This paper proposes a systematic approach to the design and analysis of a supervisory control scheme for power systems using the hybrid automata (HA) model. The proposed model for optimal controller application is derived, and the power system's overall behavior is modeled using HA to enhance its stability. Hybrid systems' formulation incorporates continuous dynamics as well as discrete switching behavior into a modeling and control framework, thus allowing a complete system description while crystallizing the concepts of safety into system design criteria. This study uses a power system HA model as a discrete event system (DES) plant and controller. In the proposed method, to present the hybrid model, the discrete events used include the presence and absence of disturbances and voltage control elements, fault, sudden load increase, capacitor bank, and under-load tap changer (ULTC) transformer. Voltage stability and control are investigated by the generators’ rotor angle, bus voltage, eigenvalues, and the stability theory of the switched linear systems. Applications in voltage control, stability, and dynamic service restoration are presented on two benchmark power systems with 12 discrete states. The simulation results reveal the effective performance of the proposed supervisory controller model to enhance voltage stability in power systems.

Research on Solar-assisted Ocean Thermal Energy Conversion System

At present, the Ocean Thermal Energy has low circulating thermal efficiency and poor power supply stability, so it has not been widely applied. To solve this problem, the combined generation system of ocean temperature difference energy and solar auxiliary heat is proposed. The multi-curved compound trough collector absorbs solar radiation energy, and layers heat exchange and energy storage with heat storage tank using heat conduction oil as medium. Then, the hot water storage and working medium preheated by warm sea water are used for efficient heat exchange in PCHE, so as to improve the system’s power generation efficiency and improve the continuity of power supply. The Solar-assisted Ocean Thermal Energy Conversion System is established by using Aspen Plus. The theoretical calculation and simulation analysis of each part of the system were carried out, and the thermal cycle with R717 as the working medium was determined. With Sansha City of Hainan Province as the background, the design is based on the installed capacity of 130kW solar auxiliary heat ocean temperature difference power generation system to verify the feasibility of the project. The energy management device takes PLC as the core, according to the load demand and the predicted power generation, through the fuzzy PID control strategy to adjust the flow of working medium and cold and hot source, and manage the power generation system. The energy management device effectively solves the intermittent problem of OTEC cycle power generation and the lack of power performance under the condition of sudden increase of power load, and realizes the system’s all-weather stable operation. Based on the traditional form of ocean temperature difference power generation, this system proposes the integration of solar energy efficient heat collection, heat storage and ocean temperature difference energy combined power generation technology, which greatly improves the system power generation efficiency and has high popularization and application value.

Discriminating flash crowds from DDoS attacks using efficient thresholding algorithm

Distributed Denial-of-Service attacks have been a challenge to cyberspace, as the attackers send a large number of attack packets similar to the normal traffic, to throttle legitimate flows. These attacks intentionally disrupt the services offered by the systems resulting in heavy cost. A flash crowd or flash event is an unexpected surge in the number of visitors to a particular website resulting in a sudden increase in server load. Flash crowds, which are legitimate flows, are difficult to be discriminated from Distributed Denial-of-Service attacks that are illicit flows. Effective and accurate detection of Distributed Denial of Service attacks still remains a challenge due to the difficulty in its detection and the false alerts generated in the case of flash crowds. There is a trade off between detection rate and false positive rate. This work deals with an efficient and early detection of distributed denial of service attacks and discriminates flash crowd by considering two network traffic parameters such as packet size and destination IP address. Using these traffic features two attributes are computed and its generalized entropies are calculated. The threshold is computed using the mean value of network attributes to detect the attacks. Threshold updater can automatically adjust the threshold values according to the changes in the channel conditions. The data sets used to evaluate the performance of the proposed approach are the MIT Lincoln Laboratory DARPA data set and a data set generated in a University network. Experimental results show this research approach achieves higher detection rate and lower false positives in a much reduced processing time as compared to the existing methods.