Minimum Average Power Research Articles

Study on heat transfer performance of cooling channels in proton exchange membrane fuel cells based on topology optimization

Based on topology optimization method, a dual-objective function topology optimization model containing minimum average temperature and minimum flow power dissipation was established in this study. Coupled with the uneven heat generation model of proton exchange membrane fuel cells, the optimal layout scheme under the target operating conditions was adaptively obtained. The effects of volume fraction, objective function weight, and parabolic inlet velocity on the flow channel structure and cooling performance of topological cooling plates were studied. The results indicate that with the increase of volume fraction, the area of fluid region increases, the average temperature and the pressure drop of cooling plate gradually decrease. At the volume fraction of 0.5, the cooling plate has the best cooling performance. The temperature difference and maximum temperature reach the minimum values of 5.45 K and 347.58 K, respectively. When the volume fraction increases from 0.4 to 0.6, the pressure difference decreases by 67.64 %. With the increase of temperature weight coefficient, the area of high-temperature area gradually decreases, and the temperature uniformity is significantly improved. When the inlet velocity of coolant is 0.025 m/s and the temperature weight coefficient is 0.9, the average and maximum temperatures of cooling plate reach the lowest values, which are 343.53 K and 344.51 K, respectively. The maximum temperature of cooling plate under parabolic inlet velocity is of 347.87 K, which is 0.29 K higher than that under uniform inlet velocity. Non-uniform coolant inlet velocity will lead to a decrease in heat transfer capacity of cooling plate and an increase in coolant power consumption.

A Wirelessly Powered System of Coherent Sensing Nodes for Fracture Mapping Applications at Temperatures up to 250 °C and Pressures up to 24 MPa

Fracture mapping is essential in hydraulic fracturing and finds applications in the oil and gas industry. Mapping of fractures using traditional radioactive or microseismic methods involves contamination and is prone to being inaccurate, thereby reducing the yield in fracturing applications. Therefore, wireless sensor networks (WSNs) with each sensing node having a small form factor and low power consumption are currently being investigated for use in such applications. This paper presents a fully battery-less system of coherent sensing nodes using wireless energy harvesting. These nodes are capable of mapping fractures reliably at temperatures up to 250 °C and pressures up to 24 MPa. Each node comprises a microchip having dimensions of 1.1 mm X 0.56 mm, two coils of 8 mm diameter each, and resonating capacitors. The microchip was fabricated in the Taiwan Semiconductor Manufacturing Company (TSMC) 0.18 μm process. The node receives a 40.68 MHz radio frequency (RF) signal in the industrial, scientific, and medical applications (ISM) band and transmits back a locked sub-harmonic 13.56 MHz ISM band RF signal. The sub-harmonic signal is generated on-chip using a digital divide-by-3 circuit, drastically reducing the microchip power consumption compared to injection-locked oscillators or phase-locked loops (PLLs). The sensor nodes used in the system have a form factor of 17 mm X 12 mm X 0.2 mm and a minimum average power consumption of 1.5 μW.

Switchable multi-wavelength actively Q-switched erbium-doped fiber laser based on nonlinear polarization rotation and Sagnac filter

This letter describes a switchable multi-wavelength actively Q-switched erbium-doped fiber (EDF) ring laser based on nonlinear polarization rotation (NPR) structure with Sagnac filter and electro-optic modulator (EOM). The intensity-dependent loss (IDL) generated by the constructed NPR structure can suppress the mode competition caused by EDF, combined with a comb filter Sagnac loop which composed of only 2-m-long polarization maintaining fiber (PMF), the constructed laser generates nine-wavelengths laser output with a constant wavelength interval of 3 nm. When the NPR structure is removed, the constructed laser generates quadruple-wavelengths laser output with 3 nm constant wavelength interval. It is proved that the effect of the NPR can suppress mode competition to achieve multi-wavelength laser output. In the laser with the constructed NPR structure, the nine-wavelengths laser output has a maximum wavelength shift of 0.21 nm and a maximum power fluctuation of 0.69 dB, while when the NPR structure is removed from the constructed laser, for the quadruple-wavelengths laser output, the maximum wavelength shift is 0.16 nm and the maximum power fluctuation is 0.29 dB. When the constructed laser with or without NPR structure, the minimum Q-switched pulse width and maximum average output power are 1.42 μs, 1.24 μs and 3.2μW, 10.2μW, respectively.

Development of optimal placement and sizing of FACTS devices in power system integrated with wind power using modified krill herd algorithm

PurposeThis study aims to intend and implement the optimal power flow, where tuning the production cost is done with the inclusion of stochastic wind power and different kinds of flexible AC transmission systems (FACTS) devices. Here, the speed with fitness-based krill herd algorithm (SF-KHA) is adopted for deciding the FACTS devices’ optimal sizing and placement integrated with wind power. Here, the modified SF-KHA optimizes the sizing and location of FACTS devices for attaining the minimum average production cost and real power depletions of the system. Especially, the objective includes reserve cost for overestimation, cost of thermal generation of the wind power, direct cost of scheduled wind power and penalty cost for underestimation. The efficiency of the offered method over several popular optimization algorithms has been done, and the comparison over different algorithms establishes proposed KHA algorithm attains the accurate optimal efficiency for all other algorithms.Design/methodology/approachThe proposed FACTS devices-based power system with the integration of wind generators is based on the accurate placement and sizing of FACTS devices for decreasing the actual power loss and total production cost of the power system.FindingsThrough the cost function evaluation of the offered SF-KHA, it was noted that the proposed SF-KHA-based power system had secured 13.04% superior to success history-based adaptive differential evolution, 9.09% enhanced than differential evolution, 11.5% better than artificial bee colony algorithm, 15.2% superior to particle swarm optimization and 9.09% improved than flower pollination algorithm.Originality/valueThe proposed power system with the accurate placement and sizing of FACTS devices and wind generator using the suggested SF-KHA was effective when compared with the conventional algorithm-based power systems.

The Impact of Scalp's Temperature on the Choice of the Best Layout for TTFields Treatment

Background and ObjectivesTumor Treating Fields (TTFields) is an FDA-approved technique used in the treatment of glioblastoma. It consists in applying an electric field (EF) with a frequency of 200 kHz using two pairs of transducer arrays. During treatment planning, the NovoTAL system is used to strategically place the arrays on the head in regions that maximize the EF at the tumor. Current should be injected at least 18 hours/day and induce a minimum EF of 1 V/cm at the tumor. To avoid any thermal harm to the patient, the temperature of the scalp is kept around 39.5°C by changing the injected current. The goal of this study was to investigate how accounting for the temperature of the scalp during treatment planning might affect the choice of the best layout suggested by NovoTAL. Furthermore, we also studied the sensitivity of the results to the metric used to evaluate the layouts. MethodsWe used a realistic head model with a virtual glioblastoma in our studies. Through the NovoTAL system we obtained five realistic array layouts and we predicted the best one for our model based on the approach currently implemented in this system. We then repeated the same type of analysis, but also accounting for the temperature during planning. In both cases we ranked the layouts based on three different criteria: the LMiPD and the LAPD (local minimum and local average power densities, respectively) in the tumor and the SAR (specific absorption rate) in the head ResultsAccounting for the temperature does not significantly affect the choice of the best layout provided that the arrays are at least 1 cm apart from each other. Otherwise, a common temperature hotspot occurs in the scalp between the closest transducers of the adjacent arrays, which limits how much current can be injected and consequently treatment effectiveness. Also, the choice of the best layout depends on the criterion used. ConclusionsAccounting for the temperature might led to significant variations in the current injected. The LMiPD might be used as a first criterion to choose the best treatment layout, followed by the LAPD and then the SAR.

Optimal Deployment of Unified Power Flow Controller on Nigerian 330 kV Grid Using Artificial Bee Colony

Transmission line power loss minimization and voltage profile improvement are challenging problems in modern power systems due to continuous increase in load demand. In this paper, an optimal location and sizing of unified power flow controller (UPFC) to improve the performance of the updated 54-bus 330 kV Nigerian network was presented. Here, the maximum power loss bus was identified to be the most favorable location for fixing the UPFC under different loading conditions; slightly underloaded (90%), normal loading (100%) and slightly over loaded (110%). The optimum location was determined using the artificial bee colony (ABC) algorithm. The work was implemented in MATLAB® 2021b environment and its performance was evaluated based on the simulation results obtained. The simulation results revealed that, ABC proved to be robust based on the facts that all the voltage profile that violate ± 5% tolerance margin of the nominal voltage criteria were kept within the acceptable limit after the UPFC optimal deployment. Moreover, the proposed approach also recorded significant reduction in the overall active and reactive power loss in the entire network with a minimum percentage average active power loss reduction of 45.3% under different loading conditions.

Working fluid selection for the geothermal-solar hybrid cycle at Olkaria II power plant in Kenya

At Olkaria II power plant located in Kenya, the brine from the separator is re-injected back into the ground. This study analyzes a flash geothermal-solar hybrid cycle using the working fluids n-butane, n-pentane, cyclopentane, hexamethyldisiloxane and toluene in order to utilize the brine. The studied working fluids have no potential to deplete the ozone or cause global warming. The working fluids were analyzed in terms of net power output and pump power required. This was done by heating Therminol VP-1 fluid to a maximum temperature of 400 °C using the parabolic trough solar collector and varying the working fluids mass flow rate, Therminol VP-1 flow rate and pressure, and the brine pressure and flow rate. They were varied to investigate their effect on the power output of the Organic Rankine Cycle. The working fluid with higher net power output was selected as a suitable working fluid for the hybrid cycle. The selected working fluid was used to determine the average hourly power output in each month of the hybrid system using the irradiance of Olkaria II power station. N-butane showed the best results in net power output hence it was selected as a suitable working fluid as compared to the other working fluids. When the hybrid system was analyzed using n-butane to obtain the hourly average power output in each month, the results revealed that the month of February has the highest hourly average power output where the Steam Turbine has an average hourly power output of 10.48 MW and Binary Turbine net power output of 18.56 MW. The minimum average hourly power output was obtained in the month of June where the Steam Turbine has an average hourly power output of 9.08 MW and Binary Turbine net power output of 16.88 MW.

Dynamic Aerial Wireless Power Transfer Optimization

Unmanned aerial vehicle (UAV)-enabled wireless power transfer (WPT) is a viable solution to remotely charge several energy receivers (ERs) in areas with intermittent access to a source of energy. However, given the limited available energy in the on-board battery of the UAV, which is mainly required to suffice propulsion energy consumption, the UAV struggles to roam seamlessly for long intervals. A key challenge is thus to efficiently use the limited battery energy, and accordingly prolong the UAV’s endurance, via controlling the underlying associated parameters such as cruising velocity. To further extend the battery lifetime, the UAV can also harness other sources of sustainable energy, such as sunlight, via solar energy harvesting. This paper studies a UAV-enabled WPT system, where a rotary-wing UAV transfers radio frequency (RF) wireless energy to several ERs at known locations. To offer uninterrupted seamless service, the UAV also harvests solar energy using solar panels. Considering the propulsion energy consumption of the UAV, we maximize the minimum average power received among all ERs over a finite cycle duration by jointly optimizing the UAV’s time allocation between harvesting and charging, flight trajectory as well as velocity, and transmit power allocation. Due to the non-convexity of the problem, we utilize the block coordinate descent (BCD) and successive convex approximation (SCA) methods. Numerical results show that the proposed solution outperforms benchmark schemes.

A 28 nm Bulk CMOS Fully Digital BPSK Demodulator for US-Powered IMDs Downlink Communications

Low-invasive and battery-less implantable medical devices (IMDs) have been increasingly emerging in recent years. The developed solutions in the literature often concentrate on the Bidirectional Data-Link for long-term monitoring devices. Indeed, their ability to collect data and communicate them to the external world, namely Data Up-Link, has revealed a promising solution for bioelectronic medicine. Furthermore, the capacity to control organs such as the brain, nerves, heart-beat and gastrointestinal activities, made up through the manipulation of electrical transducers, could optimise therapeutic protocols and help patients’ pain relief. These kinds of stimulations come from the modulation of a powering signal generated from an externally placed unit coupled to the implanted receivers for power/data exchanging. The established communication is also defined as a Data Down-Link. In this framework, a new solution of the Binary Phase-Shift Keying (BPSK) demodulator is presented in this paper in order to design a robust, low-area, and low-power Down-Link for ultrasound (US)-powered IMDs. The implemented system is fully digital and PLL-free, thus reducing area occupation and making it fully synthesizable. Post-layout simulation results are reported using a 28 nm Bulk CMOS technology provided by TSMC. Using a 2 MHz carrier input signal and an implant depth of 1 cm, the data rate is up to 1.33 Mbit/s with a 50% duty cycle, while the minimum average power consumption is cut-down to 3.3 μW in the typical corner.

Highly sensitive Laser Photo-Acoustic SF6 Gas Analyzer with 10 decades dynamic range of concentration measurement

A highly sensitive Laser Photo-Acoustic (PA) SF6 Gas Analyzer with dynamic range of ∼10 decades (∼0.1 ppb–100% SF6) has been developed and tested. Gas analyzer is built on the base of RF-excited waveguide CO2 laser, resonant differential photo-acoustic detector (PAD), and sealed-off SF6-gas-filled Ref-cell. The resonant frequency of differential PAD is measured automatically in real time (∼1750–1780 Hz, error ± 0.1 Hz). While measuring SF6 concentration (up to 1000 ppm), normalization of PAD’s absorption signals according by Ref-cell absorption signals significantly reduce the error in PA gas analyzer readings caused by spontaneous tuning of waveguide CO2 laser wavelength near ∼10.6 μm. PA gas analyzer’s background readings was ∼0.1 ppb SF6, the standard dispersion of background signal was ∼10 ppt SF6. Minimum average power of waveguide CO2 laser radiation should be no less than ∼150 mW. Dependence of speed of sound vs gas mixture composition was used to measure SF6 concentration in 0.1–100% range. Resonant frequency of differential PAD varied from ∼1780 Hz (pure N2) to ∼690 Hz (pure SF6), which, after appropriate calibration, makes it possible to measure SF6 concentration up to 100%.

Optimization of garbage dumping mechanism of intelligent sanitation vehicle based on particle swarm algorithm

Aiming at the requirements of low power consumption and light weight of the intelligent garbage collection and transportation equipment of sanitation vehicles, this paper proposes an optimization method based on the particle swarm algorithm. In this paper, the kinematic equation and dynamic equation of the mechanical claw in the dumping action are derived by using the complex interpolation approach. The optimization objectives are the minimum maximum power, the minimum average power, the minimum maximum mutation of the instantaneous driving force and the minimum time-consuming of the dumping action. The garbage dumping angle is selected as constraints, and the arc radius of the dumping track, the centre distance of the mechanical claw’s groove wheels and the time-consuming of the dumping action are optimized. The optimization results show that the optimization objectives have been well optimized except for the increased time-consuming dumping action. And the driving force should act on the axis of the lower groove wheels.

Analysis of outdoor and indoor performance and recovery values after anaerobic performance

Research Problem/Aim: The objective of this study is to examine the anaerobic performance and recovery values after anaerobic performance in terms of outdoor or indoor performance.
 Method: For this purpose, 30 male students studying at Faculty of Sports Sciences with an average age of 21.13±1.82 participated in the study voluntarily. Running-Based Anaerobic Sprint Test (RAST) was applied to the subjects twice with three days in-between as anaerobic exercise. Randomly chosen 15 subjects ran outdoors and the remaining 15 subjects ran indoors and their performance and recoveries were examined. Three days later, the subjects who ran outdoors three days ago ran indoors and those who ran indoors ran outdoors.
 Findings: Anaerobic exercise performance was compared between indoor and outdoor area. Minimum power and average power values were found to be greater indoors than outdoors (p<0.05 ve p<0.01), Peak power, fatigue index (W/sec) and fatigue index (%) values were not found to differ between indoor and outdoor areas (p>0.05). Before the anaerobic run, the athletes’ resting lactic acid (LA) and heart rate (HR) values were taken, and then RAST test was applied. The subjects’ recoveries were monitored for 10 minutes after the test. HR measurements were recorded at every minute of the recovery. On the 1st, 5th and 10th minutes of recovery, the subjects’ blood LA levels were measured. No statistically significant difference was found between outdoor and indoor resting, 1st minute, 5th minute and 10th minute LA levels according to the results of statistical analyses (p>0.05). Resting and recovery HR values were also found not to differ between outdoor and indoor performance (p>0.05).
 Conclusions: It was concluded that outdoor and indoor performance did not influence recovery up to 10 minutes after anaerobic exercise. As a conclusion, some anaerobic exercise performance was better indoors than outdoors. Recovery after an anaerobic exercise was not found to differ between indoors and outdoors.

Power Allocation in HARQ-Based Predictor Antenna Systems

In this work, we study the performance of predictor antenna (PA) systems using hybrid automatic repeat request (HARQ). Here, the PA system is referred to as a system with two sets of antennas on the roof of a vehicle. In this setup, the PA positioned in the front of the vehicle can be used to predict the channel state information at the transmitter (CSIT) for data transmission to the receive antenna (RA) that is aligned behind the PA. Considering spatial mismatch, due to the vehicle mobility, we derive closed-form expressions for the optimal power allocation and the minimum average power of the PA systems under different outage probability constraints. The results are presented for different types of HARQ protocols and we study the effect of different parameters on the performance of PA systems. As we show, our proposed approximation scheme enables us to analyze PA systems with high accuracy. Moreover, for different vehicle speeds, we show that HARQ-based feedback can reduce the outage-limited power consumption of PA systems by orders of magnitude.

Multiobjective Beamforming Power Control for Robust SINR Target Tracking and Power Efficiency in Multicell MU-MIMO Wireless System

This study proposes a multiobjective beamforming power control scheme to achieve the robust quality of service (QoS), the optimal signal-to-interference-plus-noise ratio (SINR) target tracking and the minimum average power consumption simultaneously in multicell multiuser MIMO (multicell MU-MIMO) wireless system with imperfect channel. The advantages of the proposed multiobjective beamforming power control optimization method are threefold. First, the proposed power control scheme can simultaneously achieve three objectives as follows: 1) the optimal H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> robust SINR target tracking performance, 2) the optimal H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SINR target tracking performance, and 3) the minimum average power consumption in the multicell MU-MIMO wireless system. The proposed multiobjective optimization problem (MOP) is equivalently derived as aMOP by minimizing their corresponding upper bounds under the constraint of a set of linear matrix inequalities (LMIs). Second, without the requirement of statistical information and the norm-bounded condition of the channel uncertainty, the effect of inter-cell interference, intra-cell interference, channel uncertainty, round trip delay, and noise can be efficiently attenuated by the proposed robust SINR target tracking method. Third, through the proposed LMIs-constrained multiobjective evolution algorithm (MOEA), the designer can obtain Pareto optimal solutions efficiently with a good distribution along the Pareto front to achieve the proposed multiobjective power control design. Several simulation examples with the proposed multiobjective control scheme are produced with favourable results under the guarantee of the theoretical analysis.

Memristive GAN in Analog

Generative Adversarial Network (GAN) requires extensive computing resources making its implementation in edge devices with conventional microprocessor hardware a slow and difficult, if not impossible task. In this paper, we propose to accelerate these intensive neural computations using memristive neural networks in analog domain. The implementation of Analog Memristive Deep Convolutional GAN (AM-DCGAN) using Generator as deconvolutional and Discriminator as convolutional memristive neural network is presented. The system is simulated at circuit level with 1.7 million memristor devices taking into account memristor non-idealities, device and circuit parameters. The design is modular with crossbar arrays having a minimum average power consumption per neural computation of 47nW. The design exclusively uses the principles of neural network dropouts resulting in regularization and lowering the power consumption. The SPICE level simulation of GAN is performed with 0.18 μm CMOS technology and WOx memristive devices with RON = 40 kΩ and ROFF = 250 kΩ, threshold voltage 0.8 V and write voltage at 1.0 V.

ANALISA PEMASANGAN KAPASITOR UNTUK MENINGKATKAN FAKTOR DAYA PADA TRAFO1 DI HOTEL MELIA BALI

Melia Bali-Indonesia Hotel is the first hotel of Sol Melia's management, which subsequently becomes the Bali Sol Hotel. This hotel was supplied from transformer 1 of the Melia Bali Hotel via MDP1 with 9 SDPs, with priority to supply electricity to rooms and villas. Based on the measurement results obtained currents: at each phase namely: phase R = 456 A, phase S = 445 A, phase T = 412 A and power factor of 0,84. A power factor of less than 0,85, based on the determination of an electric power tariff adjustment from PT PLN, may be subject to excess reactive power usage fees (Regulation of the Minister of Energy and Mineral Resources of the Republic of Indonesia Number 28 of 2016). Based on these data, an analysis of the installation of capacitors was carried out to increase the power factor in transformer 1 of Melia Bali Sol. The method used is to use simulation modeling with ETAP. Based on the results of the analysis of the installation of capacitors can increase the power factor by 11% to 0,95, already exceeding the minimum average power factor determined by the PLN electricity tariff adjustment. In addition, the load current decreased 12% from 442.3 A to 389.5 A.

Evaluation the Influences of Temperature, Dust and Shading on Photovoltaic System Performance

The proliferation of the use of Photovoltaic PV systems, as one of the sources of electricity that comes from renewable energy resources, attracting the researchers to investigate on the factors that have an effect on the performance of it. This paper presents an analytical study for evaluating the performance of PV system that generates 2.5 kWp through the deployment of this system to supply the electricity for the Engineering Consultant office, of the College of Engineering at Wasit University, Iraq (32.497 N, 45.842 E). The evaluation is conducted by monitoring the pre-defined system which consists of 10 PV modules as an array of two rows. The system is supervised for six months from 1st of Feb. until 31st of July, to assess the impact of temperature, shading, and dust on its’ output power and performance. The PV array is omitted to 8˚ south-west, and 40˚ in elevation. The results shows that the PV array is operated at efficiency of 12.12% and the maximum efficiency reached 13.01 during April. The average daily power of it, for the months from Feb. until July are: 1.347 kW, 1.421kW, 1.436, 1.215 kw, 1.045kW and 1.042 kW, respectively. The minimum average output power is recorded in summer season (June and July), because of the high ambient temperature in these months. The maximum reduction of power due to shading at 4 pm is 52.77% in February followed by March 47.7 % and April 22.93 %, while the maximum reduction in efficiency due to shading were 51.82 %, 44.71%, 23.01% in February, March and April, respectively. The reduction in power due to the dust accumulated after 54 days exposure to environments conditions was 7.88%.

An enhanced Gate Diffusion Input technique for low power applications

Power consumption in data manipulation strongly depends on the performance of full adder which is the primary block from which any larger circuits could be stacked. This paper addresses logic swing degradation in Gate Diffusion Input (GDI) and the glitches caused by the corresponding technique during run time. The effects of glitches at different operating frequencies were analysed. An Enhanced Gate Diffusion Input (EGDI) based full adder with focus on EGDI logic cells and its realizations has been proposed. EGDI based full adder consumes maximum average power of 40.4 pW and minimum average power of 0.595 pW for the operating frequency of 5 KHz and 500 KHz respectively. When GDI and CMOS are compared with EGDI technique, it consumes 0.01% less power than GDI technique at f0 = 50 KHz and f0 = 500 KHz respectively. The transistor level conventional simulations and power consumption have been evaluated using an Analog Device’s LTSPICE-XVII simulator with 180 nm TSMC technology libraries.

Caching and Coded Delivery Over Gaussian Broadcast Channels for Energy Efficiency

A cache-aided $K$ -user Gaussian broadcast channel is considered. The transmitter has a library of $N$ equal-rate files, from which each user demands one. The impact of the equal-capacity receiver cache memories on the minimum required transmit power to satisfy all user demands is studied. Considering uniformly random demands across the library, both the minimum average power (averaged over all demand combinations) and the minimum peak power (minimum power required to satisfy all demand combinations) are studied. Upper bounds are presented on the minimum required average and peak transmit power as a function of the cache capacity considering both centralized and decentralized caching. The lower bounds on the minimum required average and peak power values are also derived assuming uncoded cache placement. The bounds for both the peak and average power values are shown to be tight in the centralized scenario through numerical simulations. The results in this paper show that proactive caching and coded delivery can provide significant energy savings in wireless networks.

A probe-and-update method for tuning analog self-interference canceler in full-duplex radio systems

Accurate self-interference (SI) cancellation is one of the main challenges for the implementation of full-duplex radio (FDR) systems. In this letter, we proposed a new algorithm, called, probe-and-update method (PUM), to tune the gains of a multi-tap analog SI cancellation filter for orthogonal frequency division multiplexing FDR systems. PUM performs a novel gain updating procedure based on the comparison of two consecutive measurements of the residual SI power, namely, the probe value. Via sufficient number of updates, PUM could approach the minimum average residual SI power. PUM is applicable in a multipath environment and no channel knowledge is needed in advance, which considerably facilitate the implementation. Simulation results show that PUM could achieve a reasonably low residual SI power down to 5.5 dB of the noise floor in a 20-MHz system.