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Using a Neural Network to Minimize Pressure Spikes for Binary-coded Digital Flow Control Units

INTERNATIONAL JOURNAL OF FLUID POWER 2019年第3期20卷 323-351页

作者： Elsaed, Essam Abdelaziz, Mohamed Mahmoud, Nabil A. Ain Shams Univ Mech Dept Fac Engn Cairo Egypt

A unique method of improving energy efficiency in fluid power systems is called digital flow control. In this paper, binary coding control is utilized. Although this scheme is characterized by a small package size and low energy consumption, it is influenced by higher pressure peaks and larger transient uncertainty than are other coding schemes, e.g., Fibonacci coding and pulse number modulation, consequently resulting in poor tracking accuracy. This issue can be solved by introducing a delay in the signal opening/closing of the previous or subsequent valve, thus providing sufficient time for state alteration and valve processes. In a metering-in velocity control circuit, a feedforward neural network controller was used to create artificial delays according to the pressure difference over the digital flow control unit (DFCU) valves. The delayed signal samples fed to the controller were acquired through the genetic algorithm method, and the analysis was performed with MATLAB software. The results display better overall tracking accuracy than do those of other methods. Although the system exhibits low accuracy at high acceleration demands, the proposed controller still slightly increased the accuracy compared under these conditions to traditional methods.

关键词： digital hydraulics speed control pulse code modulation pressure peaks neural network

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Design and Analysis of Binary Scalar Quantizer of Laplacian Source with Applications

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INFORMATION 2020年第11期11卷 501页

作者： Peric, Zoran Denic, Bojan Savic, Milan Despotovic, Vladimir Univ Nis Fac Elect Engn Aleksandra Medvedeva 14 Nish 18000 Serbia Univ Pristina Kosovska Mitrovica Fac Sci Ive Lole Ribara 29 Kosovska Mitrovica 38220 Serbia Univ Luxembourg Dept Comp Sci Ave Fonte 6 L-4364 Esch Sur Alzette Luxembourg

A compression method based on non-uniform binary scalar quantization, designed for the memoryless Laplacian source with zero-mean and unit variance, is analyzed in this paper. Two quantizer design approaches are presented that investigate the effect of clipping with the aim of reducing the quantization noise, where the minimal mean-squared error distortion is used to determine the optimal clipping factor. A detailed comparison of both models is provided, and the performance evaluation in a wide dynamic range of input data variances is also performed. The observed binary scalar quantization models are applied in standard signal processing tasks, such as speech and image quantization, but also to quantization of neural network parameters. The motivation behind the binary quantization of neural network weights is the model compression by a factor of 32, which is crucial for implementation in mobile or embedded devices with limited memory and processing power. The experimental results follow well the theoretical models, confirming their applicability in real-world applications.

关键词： quantization Laplacian distribution clipping factor signal to noise ratio pulse code modulation delta modulation neural network

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Optimization and Analysis of a Heat Exchanger with Encapsulated Phase Change Material

Optimization and Analysis of a Heat Exchanger with Encapsula...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Karmakar, Avijit Kanani, Yousef Bhattacharya, Arunim Acharya, Sumanta Taghizadeh, Salar Ling, Kong IIT Mech Mat & Aerosp Engn Chicago IL 60616 USA Texas A&M Univ Dept Mech Engn College Stn TX 77843 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

Phase change materials are commonly utilized in several heat transfer applications due to the potential of capturing the high rates of latent heat transfer associated with phase change. In this study, the performance of a heat exchanger (HX) with encapsulated phase change material (EPCM) is studied with the intent of analyzing the thermal behavior and optimizing it's performance. The intended application for the HX is in cooling the exiting water stream from the steam condenser in a power plant. The heat exchanger consists of stacked flattened tubes enclosing PCM and arranged in sections that are alternatively exposed to the hot water and colder air. The heat exchanger is divided to separate modules with different PCM melting temperatures in the HX height. A new heat transfer and pressure drop correlations for flattened tubes were developed from 144 high fidelity large eddy simulations (LES) and used to optimize the heat exchanger performance. Genetic Algorithm (GA) is utilized in the optimization process for a specific heat capacity to minimize the capital cost (PCM volume) while maintaining a minimum value of the coefficient of performance (COP) as a measure of the operational cost. Under a specific heat load, the effect of the number of vertical modules, number of sections, HX footprint and height on the PCM volume is studied. The study shows that increasing the number of modules decreases the required PCM volume. It is also found that the amount of the required PCM volume increases for smaller footprint and height of HX. A transient model is developed to predict and analyze the unsteady thermal performance of the optimum EPCM HX design.

关键词： heat exchangers Phase change materials pulse code modulation minimum value Heat transfer Vapor condensers Specific heat Optimization Procedure Latent heat transfer

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Experiment Investigation and Analysis on Battery with PCM for Electrical Vehicle BTMS

Experiment Investigation and Analysis on Battery with PCM fo...

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International Conference on Electronics, Information and Communications (ICEIC)

作者： Sung Min Oh Euisong Kim Hyeonjung Lee Amarnathvarma Angani Teressa Thalluri Kyoo Jae Shin Busan University of Foreign Studies Busan Republic of Korea

ISBN: (数字)9781728162898

ISBN: (纸本)9781728162904

The thermal management system is necessary in electric vehicles (EVs) especially in lithium batteries due to high heat dissipation rate that effects batteries. To improve the heat transfer rate of phase change material in lithium polymer pouch battery, the battery thermal management system by using different phase change materials such as RT15, RT31, and EG5 &EG26 was designed and experimentally investigated in this paper. The systematic investigation on thermo-physical properties of the used PCMs on the performance of the system was conducted. The thermal performance of the system such as temperature reduction and distribution is discussed in detail. The results showed that the temperature on the battery surface is increased to 37.6°C upon different discharge rates without PCM. By incorporating EG26 on the battery surface the temperature difference is observed as 30. 1°C. Slow temperature rise rate and uniform temperature distribution is observed. In addition, numerical research with the computational fluid dynamics (CFD) software, FLUENT also carried out. The numerical results are in good agreement with experiment data. The experiment and simulation results demonstrated that expanded graphite phase change material coupled battery thermal management system presents an excellent cooling performance.

关键词： battery management systems battery powered vehicles computational fluid dynamics cooling graphite numerical analysis phase change materials temperature distribution thermal management (packaging) Phase change materials Electric vehicles Battery management systems Batteries Temperature distribution computational fluid dynamics pulse code modulation Thermal management Graphite graphene Numerical Analysis Experimental data Cooling Discharge rate heat transfer rate

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Inplementation of PCM Coding and Decoding Algorithm Based on C Language

Inplementation of PCM Coding and Decoding Algorithm Based on...

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Advanced Electronic Materials, Computers and Software Engineering (AEMCSE), International Conference on

作者： Yue Wang Zhenyu Wang Xiaozhuo Li Jianghuan Xie Kai Qu Kunming University of Science and Technology Kunming China Xi'an University of posts and Telecommunications Xi'an China North Western University Xi'an China

ISBN: (数字)9781728181431

ISBN: (纸本)9781728181448

In order to solve the problem that the A-law 13 polyline coding algorithm lacks a specific programming language simulation, C language is used to implement the algorithm in this paper. First, the polar code is obtained according to the positive and negative sample values. Then the paragraph code and the inner code are obtained and finally decoded. Experimental results show that the program can realize A-law 13 polyline encoding and decoding, and for a given sample value, it can obtain its 8-bit encoding. Compared with the bit-wise encoding method, the program is more efficient.

关键词： PCM coding C language C language decoding algorithm coding pulse code modulation Broken line DECODING

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An approach for ber determination using logged aeronautical telemetry data 55

An approach for ber determination using logged aeronautical ...

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55th Annual International Telemetering Conference: Cultivating the Next Generation of Range Engineers, ITC 2019

作者： Tamakuwala, Jimmy B. Sonar, Souvik Jena, Avijit Integrated Test Range DRDO Chandipur India Defence Research and Development Organization

ISBN: (纸本)9781713801887

BER is regarded as the link-performance metric in a digital communication system. It is a function of Eb/N0 and is dependent on the modulation scheme used. This relation is often used in prediction of ground telemetry systems performance for a mission configuration. However, there is no objective way of comparing the post flight results, as BER measurement in a flight test is not practically feasible for want of transmitting sufficient reference bit patterns. In this paper, an indirect way of computing BER and, in turn, link Eb/N0 is proposed for a PCM/FM link based on the frame synchronised data logged by the ground telemetry equipment. Using known quantities like bit rate and frame rate, a quantity defined as frame loss rate is computed. Applying the relations between frame loss probability, frame sync pattern and SFID information in the PCM format, an approach for bit error probability is demonstrated based on field data. By using a sliding window over a fixed length of data, BER for the entire flight duration can be determined as a function of flight time with the step size of the length of data window. © 2019 International Foundation for Telemetering. All rights reserved.

关键词： pulse code modulation

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Target detection in anechoic chamber based on the interrupted transmitting and receiving of PCM signal

Target detection in anechoic chamber based on the interrupte...

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IET International Radar Conference (IET IRC 2020)

作者： F. Zhao X. Liu A. Xie Q. Wu National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics & Information System Changsha 410073 P. R. China

Phase coded modulation (PCM) signal has been widely used in target detection at the out-field. However, when the PCM signal is utilized in the anechoic chamber for target detection, the target echo returns before the signal is fully transmitted, which results in the signal coupling at the receiver. In this paper, the interrupted transmitting and receiving (ITR) is adopted to solve the problem. Then, the procedure of target detection with PCM signal in anechoic chamber is proposed. The constraints of the ITR parameters are discussed according to the anechoic chamber size and the PCM signal parameters. By conducting the numerical simulations, the effectiveness of the proposed target detection method is verified.

关键词： phase coding radar signal processing echo pulse code modulation object detection anechoic chambers (electromagnetic)

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An experimental evaluation and prototyping for visible light communication

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COMPUTERS & ELECTRICAL ENGINEERING 2018年 72卷 248-265页

作者： Khalifeh, Ala' F. AlFasfous, Nael Theodory, Ramzi Giha, Serina Darabkh, Khalid A. German Jordanian Univ Elect & Commun Engn Dept Amman Jordan TUM Dept Elect Engn Munich Germany Saarland Univ Elect Engn Dept Saarbrucken Germany Univ Jordan Dept Comp Engn Amman Jordan

As the research community is moving toward 5G technology, it is important to keep up this growth by developing new technologies and mechanisms that fulfill its requirements such as spectrum availability, wireless connectivity and coverage. Visible Light Communication (VLC) has been proposed as an efficient way of utilizing the visible wireless spectrum for proving lightning and carrying information utilizing the highly available visible spectrum. In this paper, an experimental evaluation and prototyping are presented utilizing off-the-shelf electronic components and the Telecommunications Instructional Modelling System (TIMS), which is a flexible modelling and prototyping technique widely used for building communication systems. The proposed prototypes are supported by a survey that was conducted among engineering students to get their feedback in regards to VLC, TIMS and 5G technologies. The aim of this paper is to provide the means to pave the way toward educating the students and new technology adopters concerning VLC along with facilitating its deployment. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Visible light communication 5G Telecommunications Instructional Modelling System pulse code modulation

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Investigation of heat transfer inside a PCM-air heat exchanger: a numerical parametric study

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HEAT AND MASS TRANSFER 2018年第8期54卷 2433-2442页

作者： Herbinger, Florent Bhouri, Maha Groulx, Dominic Dalhousie Univ Mech Engn Dept Halifax NS Canada

In this paper, the use of PCMs for thermal storage of energy in HVAC applications was investigated by studying numerically the thermal performance of a PCM-air heat exchanger. The PCM used in this study was dodecanoic acid. A symmetric 3D model, incorporating conductive and convective heat transfer (air only) as well as laminar flow, was created in COMSOL Multiphysics 5.0. Simulations examined the dependence of the heat transfer rate on the temperature and velocity of the incoming air as well as the size of the channels in the heat exchanger. Results indicated that small channels size lead to a higher heat transfer rates. A similar trend was also obtained for high incoming air temperature, whereas the heat transfer rate was less sensitive to the incoming air velocity.

关键词： Heat transfer laminar flow air exchanger heat storage Parametric study air velocity pulse code modulation heat transfer rate conductivity heat exchangers channels

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Prospectively Validated Proteochemometric Models for the Prediction of Small-Molecule Binding to Bromodomain Proteins

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JOURNAL OF CHEMICAL INFORMATION AND MODELING 2018年第9期58卷 1870-1888页

作者： Giblin, Kathryn A. Hughes, Samantha J. Boyd, Helen Hansson, Pia Bender, Andreas Univ Cambridge Dept Chem Ctr Mol Informat Lensfield Rd Cambridge CB2 1EW England AstraZeneca IMED Biotech Unit Computat Chem Oncol Cambridge CB10 1XL England AstraZeneca IMED Biotech Unit Discovery Biol Discovery Sci SE-43150 Gothenburg Sweden AstraZeneca IMED Biotech Unit Staff Drug Safety & Metab Cambridge CB4 0WG England

bromodomain-containing proteins are a ligandable family of epigenetic readers, which play important roles in oncological, cardiovascular, and inflammatory diseases. Achieving selective inhibition of specific bromodomains is challenging, due to the limited understanding of compound and target selectivity features. In this study we build and benchmark proteochemometric (PCM) classification models on bioactivity data for 15,350 data points across 31 bromodomains, using both compound fingerprints and binding site protein descriptors as input variables, achieving a maximum performance as measured by the Matthew's Correlation Coefficient (MCC) of 0.83 on the external test set. We also find that histone peptide binding data can be used as a target descriptor to build a high performing PCM model (MCC 0.80), showing the transferability of peptide interaction information to modeling small-molecule bioactivity. 1,139 compounds were selected for prospective experimental testing by performing a virtual screen using model predictions and implementing conformal prediction, which resulted in 319 correctly predicted compound-target pair actives and the correct prediction for certain selectivity profile combinations of the four bromodomains tested against. We identify that conformal prediction can be used to fine-tune the balance between hit retrieval and hit structural diversity in a virtual screening setting. PCM can be applied to future virtual screening and compound design, including off-target prediction for bromodomains.

关键词： virtual screen small molecule Inflammatory Disorder Bromodomain pulse code modulation Portability compounds MCC Genes Input variables

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