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SSRN 2024年

作者： Jang, Yongjun Kang, Myeongjin Kang, Yong Guk Lee, Dongtak Jung, Hyo Gi Yoon, Dae Sung Kim, Jongseong Park, Yongdoo Department of Biomedical Sciences College of Medicine Korea University Seoul Korea Republic of School of Biomedical Engineering Korea University Seoul Korea Republic of Interdisciplinary Program in Precision Public Health Korea University Seoul Korea Republic of

Cardiac fibroblasts play an important role in heart homeostasis, regeneration, and disease by producing extracellular matrix (ECM) proteins and remodeling enzymes. Under normal conditions, fibroblasts exist in a quiescent state and maintain homeostasis, such as tissue structure and ECM turnover. However, if they become activated upon stimuli, such as injury, aging, or mechanical stress, which can lead to disease through excessive cell proliferation and ECM production. In addition to studying fibroblasts in disease progression, their role in cardiac maturation during development and whether the mechanism of cytokine and ECM production is similar to that observed during disease progression is unclear. In this study, we examined the functional and structural maturation of cardiac tissue by modulating fibroblast activity using an in vitro model of cardiac bundle formation. In this model, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and human cardiac fibroblasts (CFBs) were co-cultured in a fibrin gel and their morphology, beating characteristics, beating force, and mRNA expression profiles were analyzed. The results indicated that the cardiac bundle model matured structurally and functionally through tissue contraction and collagen deposition by fibroblasts, whereas inhibition of these ECM remodeling reduced maturation. In particular, the expression of second harmonic generation (SHG) and COL1A revealed that while activated fibroblasts induce structural maturation through sustained collagen deposition, excessive collagen accumulation can reduce functional maturation. Our data suggest that collagen type I expression by cardiac fibroblasts is essential for myocardial tissue maintenance and development through ECM remodeling. Furthermore, the regulation of collagen deposition by fibroblast activity is a crucial factor that influences cardiac development and disease progression. © 2024, The Authors. All rights reserved.

关键词： Stem cells

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Effect of an antiferromagnetic order on tailoring Dzyaloshinskii- Moriya interaction in Pt/Co/IrMn trilayer

Effect of an antiferromagnetic order on tailoring Dzyaloshin...

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Magnetic Conference - Short Papers (INTERMAG Short Papers), IEEE International

作者： Sheng-Huai Chen Chao-Yao Yang Chih-Huang Lai Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu Taiwan Undergraduate Degree Program of Systems Engineering and Technology National Yang Ming Chiao Tung University Hsinchu Taiwan

Antiferromagnet (AFM) has currently participated in the spin-orbit torque (SOT) magnetoresistive random access memory (MRAM) technolopgy due to its great potential to be applied to the field-free SOT switching and promote the thermal stability of MRAM. However, effect of the introduction of AFM into the basic structure of SOT-MRAM composed of a heavy metal/ferromagnet (FM) bilayer was still not comprehensively understood. This work reports the effect of how an antiferromagnetic (AFM) order modifies the strength of Dzyaloshinskii-Moriya interaction (DMI) in a heavy metal (Pt)/FM (Co)/AFM (IrMn) trilayer, studied by SOT switching and loop-shift method. Increasing the AFM order reflected on exchange bias (H ex ) through increasing the thickness of IrMn appears to significantly reduce the DMI strength of the trilayer, which leads to the reduction of the external field for yielding a complete SOT switching. The reduced DMI strength may ascribe to the Hex-hosted uni-directional anisotropy suppressing the neighboring spin canting in the FM layer. This stabilization for the magnetic moments via the H ex -hosted uni-directional anisotropy also improved the stability of SOT switching on the random read/write characterization, in which the strong AFM order would promote the memristivity for neuromorphic application and the weak AFM order would give rise to the stochasticity for the purpose of physically unclonable functionality. This work demonstrates the significance of an intrinsic tuning over the AFM order would serve as a switch to turn the SOT device into a stochastic/memristive cell to bridge probabilistic and neuromorphic computing.

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Distance Sampling-based Paraphraser Leveraging ChatGPT for Text Data Manipulation

arXiv

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arXiv 2024年

作者： Oh, Yoori Han, Yoseob Lee, Kyogu Department of Intelligence and Information Seoul National University Seoul Korea Republic of Department of Intelligence and Information Interdisciplinary Program in Artificial Intelligence AI Institute Seoul National University Seoul Korea Republic of Department of Electronic Engineering Department of Intelligent Semiconductors Soongsil University Seoul Korea Republic of

There has been growing interest in audio-language retrieval research, where the objective is to establish the correlation between audio and text modalities. However, most audio-text paired datasets often lack rich expression of the text data compared to the audio samples. One of the significant challenges facing audio-text datasets is the presence of similar or identical captions despite different audio samples. Therefore, under many-to-one mapping conditions, audio-text datasets lead to poor performance of retrieval tasks. In this paper, we propose a novel approach to tackle the data imbalance problem in audio-language retrieval task. To overcome the limitation, we introduce a method that employs a distance sampling-based paraphraser leveraging ChatGPT, utilizing distance function to generate a controllable distribution of manipulated text data. For a set of sentences with the same context, the distance is used to calculate a degree of manipulation for any two sentences, and ChatGPT’s few-shot prompting is performed using a text cluster with a similar distance defined by the Jaccard similarity. Therefore, ChatGPT, when applied to few-shot prompting with text clusters, can adjust the diversity of the manipulated text based on the distance. The proposed approach is shown to significantly enhance performance in audio-text retrieval, outperforming conventional text augmentation techniques. © 2024, CC BY.

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Comparative Analysis between Three-Leg Interleaved and Conventional Bidirectional Converters Applied in Battery of Wind Power-Battery Unit Supplying an Islanded Microgrid

Comparative Analysis between Three-Leg Interleaved and Conve...

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IEEE General Meeting Power& Energy Society

作者： André C. Do Nascimento Giusep M. S. Ribeiro Lindemberg R. de Lima Pedro A. de Alcântara Luana C. S. Soares Luciano S. Barros Camila M. V. Barros Electrical Engineering Graduate Program Federal Institute of Pará Belém Brazil Electrical Engineering Graduate Program Federal University of Paraíba João Pessoa Brazil Mathematics and Computational Modeling Graduate Program Federal University of Paraíba João Pessoa Brazil Computer Systems Department Federal University of Paraíba João Pessoa Brazil

ISBN: (数字)9798350381832

ISBN: (纸本)9798350381849

Battery energy storage systems (BESS) are crucial for microgrids, enhancing dynamic performance and mitigating uncertainties inherent to isolated environments characterized by intermittent power generation. When microgrid is supplied by wind power in connection with BESS, the bidirectional DC-DC converter associated with BESS assumes a critical responsibility—ensuring the control of a wind power supplied DC-link. This permits the Voltage Source Inverter (VSI) to synthesize consistent voltages for the connected AC load. However, challenges emerge, particularly in arduous stress on switches of the bidirectional converter attributed to elevated current ripple. This stress does not only prejudice the overall system’s functioning but can also potentially leading it to shutdown in case of switch failure. Traditionally, the conventional buck-boost converter topology has been the go-to choice for this application, nevertheless, exploring novel converter topologies, such as interleaved bidirectional DC-DC converter (IBDC) has garnered attention, promising enhanced performance. This paper’s goal is to conduct a comparative analysis of the operation of these converters in an islanded microgrid supplied by a single Permanent Magnet Synchronous Generators (PMSG) small-scale wind turbine with a BESS system. Load variation with Maximum Power Point Tracking (MPPT) operation of the PMSG is performed during MATLAB/Simulink environment simulations. The results suggest significant advantages for the interleaved three-phase converter, such as reduced battery charging current ripple, switch disturbance, and voltage ripple in the DC-link.

关键词： Maximum power point trackers Magnetic separation Microgrids DC-DC power converters Wind power generation Permanent magnets Batteries Topology Wind turbines Stress

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IMPROVED BASS MODEL USING SALES PROPORTIONAL AVERAGE FOR ONE CONDITION OF MONO PEAK CURVES

arXiv

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arXiv 2024年

作者： Sleem, Ahmad Abu Alromema, Mohammed Abdel-Aal, Mohammad A.M. Industrial & Systems Engineering Department King Fahd University of Petroleum and Minerals Dhahran31261 Saudi Arabia Interdisciplinary Research Center of Smart Mobility & Logistics King Fahd University of Petroleum and Minerals Dhahran31261 Saudi Arabia

This study provides a modified Bass model to deal with trend curves for basic issues of relevance to individuals from all over the world, for which we collected 16 data sets from 2004 to 2022 and that are available on Google servers as "google trends". It was discovered that the Bass model did not forecast well for curves that have a mono peak with a sharp decrease to some level then have semi-stable with small decrement sales for a long time, thus a new parameter based on r1 and r2 (ratios of average sales) was introduced, which improved the model's prediction ability and provided better results. The model was also applied to a data set taken from the Kaggle website about a subscriber digital product offering for financial services that includes newsletters, webinars, and investment recommendations. The data contain 508932 data points about the products sold during 2016-2022. Compared to the traditional Bass model, the modified model showed better results in dealing with this condition, as the expected curve shape was closer to real sales, and the sum of squares error (SSE) value was reduced to a ratio ranging between (36.35-79.3%). Therefore, the improved model can be relied upon in these conditions. © 2024, CC BY.

关键词： Sales

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Printed Monopole Antenna Design for Early Brain Tumor Detection 2

Printed Monopole Antenna Design for Early Brain Tumor Detect...

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2nd International Conference on Electronics, Energy and Measurement, IC2EM 2023

作者： Boutaa, Mohammed Aissaoui, Djelloul Chaabane, Abdelhalim Attia, Hussein Ziane Achour University of Djelfa Telecommunications and Smart Systems Laboratory Faculty of Science and Technology Djelfa17000 Algeria Faculté des Sciences et de la Technologie Laboratoire des Télécommunications-LT Université 8 Mai 1945 Guelma BP 401 Guelma24000 Algeria King Fahd University of Petroleum and Minerals Interdisciplinary Research Center for Communication Systems and Sensing Electrical Engineering Department Dhahran31261 Saudi Arabia

ISBN: (纸本)9798350314243

The purpose of this research is to design a simple miniaturized microstrip antenna and detect variations in its reflection response to locate tumors in the human brain. The proposed antenna has a size of 36×32×1.6 mm3. This antenna is designed to operate at a resonant frequency of 2.45 GHz, which align with the Industrial, Scientific, and Medical (ISM) band. The designed antenna has an omnidirectional radiation pattern with a maximum gain of about 1.43 dBi. For the intended application, numerical simulations are performed using a tumor with a radius of 5 mm. The reflection response of the proposed antenna is investigated for two cases: one without a tumor and another with a tumor placed at three different positions inside the brain. When there is no tumor present, the resonance frequency is similar to that of an antenna in open space. However, in the presence of a tumor, there is a shift and increase in the resonance frequency, which is directly proportional to the distance between the antenna and the head. This shift serves as an indication of the presence of a tumor. © 2023 IEEE.

关键词： Tumors

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Modified Sliding Model Control for Resilient Speed Control of Wind Energy systems

Modified Sliding Model Control for Resilient Speed Control o...

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IEEE PES Transmission and Distribution Conference and Exposition

作者： Abdulrahman Abu-Askar Khalid Abdullah Khan Muhammad Khalid Sustainable Innovations Company Limited Al-Khobar KSA Electrical Engineering Department King Fahd University of Petroleum & Minerals (KFUPM) Dhahran KSA Interdisciplinary Research Center for Renewable Energy and Power Systems KFUPM Dhahran KSA

ISBN: (数字)9798350316377

ISBN: (纸本)9798350316384

This research presents an improved control approach for wind turbine system using an observer-based sliding model control (SMC) approach with an extended state observer (ESO) to estimate and compensate for the system disturbances. The effectiveness of the proposed ESO-enhanced SMC controller is demonstrated through simulation using Python. The simulation results shows that the ESO-enhanced SMC controller outperforms the classic SMC controller in terms of control effort and disturbance rejection, in addition to minimizing high frequency switching of the controller output and minimizing chattering of the system states. The proposed controller provides a practical and efficient solution for regulating wind turbines in variable wind condition, while reducing the wear and tear of the system components. The controller’s design and performance evaluation can be extended to other applications with similar nonlinear dynamics and disturbances.

关键词： Performance evaluation Wind energy System dynamics Simulation Velocity control Rotors Observers

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Model for Anomaly Detection in Reducing Water Losses in the Distribution Network of Peru using Machine Learning Algorithms

Model for Anomaly Detection in Reducing Water Losses in the ...

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Software engineering and Computer Science (CSECS), International Conference on

作者： Mayra Rivera Pricila Lucero José Luis Castillo-Sequera Lenis Wong Information Systems Engineering Program Universidad Peruana de Ciencias Aplicadas Lima Peru Department of Computer Science Group: Health Computing and Intelligent System Universidad de Alcalá Alcalá de Henares Spain

ISBN: (数字)9798331522216

ISBN: (纸本)9798331522223

Water leakage in distribution networks is a significant challenge, especially in regions with limited infrastructure like Huancayo, Peru, where losses account for 32.82% of the distributed volume. This study introduces a machine learning-based approach to detect leaks using four algorithms: Autoencoder LSTM, Isolation Forest, One-Class SVM, and K-Nearest Neighbors (KNN). The methodology involved preprocessing historical consumption data (2018–2024) into 12-month temporal sequences per client and evaluating the models based on F1 Score, Precision, and Mean Absolute Error (MAE). Among the algorithms, the Autoencoder LSTM demonstrated superior performance with the highest precision (0.89) and the lowest MAE (0.00402). Its robustness in high-variability contexts enables early and reliable leak detection, providing a cost-effective solution for optimizing water management in resource-constrained environments.

关键词： Support vector machines Machine learning algorithms Autoencoders Distribution networks Forestry Nearest neighbor methods Robustness Leak detection Long short term memory Water resources

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Optimal Scheduling of a Tri-Generation Plant for Blue Ammonia, Hydrogen, and Power

Optimal Scheduling of a Tri-Generation Plant for Blue Ammoni...

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IEEE Industry Applications Society Annual Meeting (IAS)

作者： Abubkr Hassan Ali T. Al-Awami Wael A. Fouad MA Abido Electrical Engineering Department King Fahd University of Petroleum & Minerals Dhahran Saudi Arabia Interdisciplinary Research Center for Smart Mobility & Logistics Dhahran Saudi Arabia Chemical Engineering Department King Fahd University of Petroleum & Minerals Dhahran Saudi Arabia Interdisciplinary Research Center for Refining & Advanced Chemicals Dhahran Saudi Arabia Interdisciplinary Research Center for Renewable Energy & Power Systems Dhahran Saudi Arabia

As the world's energy demand grows and fossil fuels become increasingly burdensome, governments and stake-holders have recognized the importance of reducing carbon dioxide emissions to combat climate change. Hydrogen has been identified as a crucial component of successful decarbonization efforts. However, because hydrogen has a low density, it must typically be compressed at high pressures or liquefied in order to be transported and stored effectively. This study introduces a new method for generating compressed hydrogen, ammonia, and electricity through a multigeneration process. The process involves using a catalytic membrane reactor to recover hydrogen, while simultaneously capturing all $CO_{2}$ through a membrane. The process also incorporates a high-temperature solid oxide fuel cell for efficient heat and electricity integration. Furthermore, the study presents an optimization model for the multigeneration process that helps to identify the most effective operational production patterns for generating hydrogen, ammonia, and electricity. Optimization is performed on an hourly basis for a duration of one week. According to the findings, the production of hydrogen is deemed to be the most beneficial among the three options, followed by ammonia, then electricity.

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Investigation of Heat Transfer and System Efficiency in a Solar Electric Greenhouse Dryer Using Dimensionless Analysis

Investigation of Heat Transfer and System Efficiency in a So...

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Sustainable Power and Energy Conference (iSPEC)

作者： Asim Ahmad Kashif Irshad Biplab Das Interdisciplinary Research Center for Sustainable Energy Systems (IRC-SES) King Fahd University of Petroleum and Minerals (KFUPM) Dhahran Saudi Arabia Department of Mechanical Engineering PVT Laboratory National Institute of Technology Silchar Assam India

ISBN: (数字)9798350395075

ISBN: (纸本)9798350395082

This study investigates the integration of an electric heater and a greenhouse dryer, enhanced by thermal storage technology, to improve drying efficiency. By applying heat storage materials to the dryer bed, the system's thermal performance is significantly enhanced. The research focuses on evaluating the thermal characteristics of the modified dryer under no-load conditions, conducted from June 2024 to August 2024 during peak sunshine hours at the PVT Lab, National Institute of Technology Silchar (24.75°N, 92.79°E), Assam, India. Experiments were performed between the 15th and 17th of each month. The dryer incorporates an opaque north wall, contributing to its optimized design. Results indicate that the modified solar electric greenhouse dryer outperforms conventional solar dryers, with significant improvements in thermal efficiency. Key dimensionless parameters, including the Nusselt, Grashof, Prandtl, and Rayleigh numbers, were computed numerically based on experimental data to assess the system's heat transfer dynamics. Additionally, the system's electrical efficiency was evaluated.

关键词： Temperature Green products Rural areas Moisture Crops Solar energy Hybrid power systems Solar heating Heat transfer Resistance heating

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