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Truly optimal semi-active damping to control free vibration of a single degree of freedom system

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 142-145页

作者： Viet Duc La Ngoc tuan nguyen Institute of Mechanics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

This paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as the performance index.A one-time switching damping controller is proposed and *** pontryagin maximum principle is used to prove that no other form of semi-active damping can provide the better performance than the proposed one-time switching damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

Unknown DDoS Attack Detection with Fuzzy C-Means Clustering and Spatial Location Constraint Prototype Loss

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Computers, Materials & Continua 2024年第2期78卷 2181-2205页

作者： Thanh-Lam nguyen HaoKao Thanh-tuan nguyen Mong-Fong Horng Chin-Shiuh Shieh Department of Electronic Engineering National Kaohsiung University of Science and TechnologyKaohsiung807618Taiwan Department of Electronic and Automation Engineering Nha Trang UniversityNha Trang650000Vietnam

Since its inception,the Internet has been rapidly *** the advancement of science and technology and the explosive growth of the population,the demand for the Internet has been on the *** applications in education,healthcare,entertainment,science,and more are being increasingly deployed based on the ***,malicious threats on the internet are on the rise as *** Denial of Service(DDoS)attacks are among the most common and dangerous threats on the internet *** scale and complexity of DDoS attacks are constantly *** Detection Systems(IDS)have been deployed and have demonstrated their effectiveness in defense against those *** addition,the research of Machine Learning(ML)and Deep Learning(DL)in IDS has gained effective results and significant ***,one of the challenges when applying ML and DL techniques in intrusion detection is the identification of unknown *** attacks,which are not encountered during the system’s training,can lead to misclassification with significant *** this research,we focused on addressing the issue of Unknown Attack Detection,combining two methods:Spatial Location Constraint Prototype Loss(SLCPL)and Fuzzy C-Means(FCM).With the proposed method,we achieved promising results compared to traditional *** proposed method demonstrates a very high accuracy of up to 99.8%with a low false positive rate for known attacks on the Intrusion Detection Evaluation Dataset(CICIDS2017)***,the accuracy is also very high,reaching 99.7%,and the precision goes up to 99.9%for unknown DDoS attacks on the DDoS Evaluation Dataset(CICDDoS2019)*** success of the proposed method is due to the combination of SLCPL,an advanced Open-Set Recognition(OSR)technique,and FCM,a traditional yet highly applicable clustering *** has yielded a novel method in the field of unknown attack *** further expands the trend of applying DL and M

关键词： Cybersecurity DDoS unknown attack detection machine learning deep learning incremental learning convolutional neural networks(CNN) open-set recognition(OSR) spatial location constraint prototype loss fuzzy c-means CICIDS2017 CICDDoS2019

One-loop contributions for h→ℓℓγ and e−e+→hγ in the U(1)_(B−L) extension of the standard model

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Chinese Physics C 2024年第5期48卷 23-49页

作者： Tran dzung Tri Thanh Huy nguyen Khiem Hong Phan Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh City 700000Vietnam Faculty of Natural Sciences Duy Tan UniversityDa Nang City 550000Vietnam VNUHCM-University of Science 227 Nguyen Van CuDistrict 5Ho Chi Minh CityVietnam

We present one-loop contributions for h→ℓℓγ with ℓ=νe,μ,τ,e,μ and e−e+→hγ in the U(1)_(B−L) extension of the standard model. In the phenomenological results, the signal strengths for h→ℓℓγ at the Large Hadron Collider and for e−e+→hγ at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral B−L models. We found that the contributions from the neutral gauge boson Z′ to the signal strengths are rather small. Consequently, the effects will be difficult to probe at future colliders. However, the impacts of charged Higgs and CP-odd Higgs in the chiral B−L model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.

关键词： Higgs phenomenology one-loop Feynman integrals analytic methods for quantum field theory dimensional regularization future lepton colliders

One-loop contributions for h→?■γ and e-e+→hγ in the U（1）B-L extension of the standard model

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Chinese Physics C 2024年第5期 27-53页

作者： Tran dzung Tri Thanh Huy nguyen Khiem Hong Phan Institute of Fundamental and Applied Sciences Duy Tan University Faculty of Natural Sciences Duy Tan University VNUHCM-University of Science

We present one-loop contributions for h→?■γ with l=ve,μ,τ,e,μ and e-e+→ hγ in the U（1）B-Lextension of the standard *** the phenomenological results,the signal strengths for h→?■γ at the Large Hadron Collider and for e-e+→hγ at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral B-L *** found that the contributions from the neutral gauge boson Z' to the signal strengths are rather ***,the effects will be difficult to probe at future ***,the impacts of charged Higgs and CP-odd Higgs in the chiral B-L model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.

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Reviewing Stability Criteria for Positive Homogeneous Systems and Adding One for Discrete-Time Cases with Degree Less Than One

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Circuits and Systems 2024年第1期15卷 1-11页

作者： nguyen Quang tuan Faculty of Information Technology Nha Trang University Khanh Hoa Vietnam

The article synthesizes and presents the results regarding the stability of positive homogeneous systems that have been researched and published in recent years. Next, we provide a sufficient condition for global exponential stability in the case of discrete-time positive homogeneous systems with an order less than one with time-varying delays.

关键词： Exponential Stability Homogeneous Systems Positive Systems Positive Homogeneous Systems

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： Pham T.Nhung Do T.Hoai Pierre Darriulat Pham tuan-Anh Pham N.Diep nguyen B.Ngoc Tran T.Thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Is convenience really king? Comparative evaluation of catastrophic costs due to tuberculosis in the public and private healthcare sectors of Viet Nam: a longitudinal patient cost study

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贫困所致传染病(英文) 2024年第2期13卷 1-12页

作者： nguyen Hoa Binh Quang Vo Luan nguyen Forse Rachel Jeanette Wiemers Anja Maria Christine Huynh Huy Ba Dong Thuy Thi Thu Phan Yen Thi Hoang Creswell Jacob Dang Thi Minh Ha nguyen Lan Huu Shedrawy Jad L?nnroth Knut nguyen tuan Dinh Van Dinh Luong Annerstedt Kristi Sidney Codlin Andrew James National Lung Hospital Ha Noi Viet Nam Friends for International TB Relief Ha Noi Viet Nam Department of Global Public Health WHO Collaboration Centre On Tuberculosis and Social Medicine Karolinska Institute Stockholm Sweden Stop TB Partnership Geneva Switzerland Pham Ngoc Thach Hospital Ho Chi Minh City Viet Nam

Background In Viet Nam, tuberculosis (TB) represents a devastating life-event with an exorbitant price tag, partly due to lost income from daily directly observed therapy in public sector care. Thus, persons with TB may seek care in the private sector for its flexibility, convenience, and privacy. Our study aimed to measure income changes, costs and catastrophic cost incurrence among TB-affected households in the public and private *** Between October 2020 and March 2022, we conducted 110 longitudinal patient cost interviews, among 50 patients privately treated for TB and 60 TB patients treated by the National TB Program (NTP) in Ha Noi, Hai Phong and Ho Chi Minh City, Viet Nam. Using a local adaptation of the WHO TB patient cost survey tool, participants were interviewed during the intensive phase, continuation phase and post-treatment. We compared income levels, direct and indirect treatment costs, catastrophic costs using Wilcoxon rank-sum and chi-squared tests and associated risk factors between the two cohorts using multivariate *** The pre-treatment median monthly household income was significantly higher in the private sector versus NTP cohort (USD 868 vs USD 578;P=0.010). However, private sector treatment was also significantly costlier (USD 2075 vs USD 1313;P=0.005), driven by direct medical costs which were 4.6 times higher than costs reported by NTP participants (USD 754 vs USD 164;P<0.001). This resulted in no significant difference in catastrophic costs between the two cohorts (Private: 55% vs NTP: 52%;P=0.675). Factors associated with catastrophic cost included being a single-person household [adjusted odds ratio [(aOR=13.71; 95% confidence interval (CI): 1.36–138.14;P=0.026], unemployment during treatment (aOR=10.86; 95%CI: 2.64–44.60;P<0.001) and experiencing TB-related stigma (aOR=37.90; 95%CI: 1.72–831.73;P=0.021).Conclusions Persons with TB in Viet Nam face similarly high risk of catastrophic costs whether treated in the

关键词： Tuberculosis Patient cost Catastrophic cost Private sector Comparative analysis Viet Nam

An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

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Science China(Technological Sciences) 2009年第1期52卷 52-66页

作者： tuan Anh nguyen Recep AVCI Corrosion and Sustainable Infrastructure Laboratory Western Transportation InstitutePO Box 174250College of Engineering Montana State University Bozeman Imaging and Chemical Analysis Laboratory Department of Physics Montana State University Bozeman

The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCl and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride and the admixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the polarization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

关键词： corrosion inhibitor rebar corrosion steel-mortar interface FESEM EDX XPS EIS

An Efficient Differential Evolution for Truss Sizing Optimization Using AdaBoost Classifier

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 429-458页

作者： Tran-Hieu nguyen Anh-tuan Vu Hanoi University of Civil Engineering Hanoi100000Vietnam

Design constraints verification is the most computationally expensive task in evolutionary structural optimization due to a large number of structural analyses thatmust be *** a surrogatemodel to approximate the behavior of structures instead of the exact structural analyses is a possible solution to tackle this ***,most existing surrogate models have been designed based on regression *** paper proposes a novel method,called CaDE,which adopts a machine learning classification technique for enhancing the performance of the Differential Evolution(DE)*** proposed method is separated into two *** the first optimization stage,the original DE is implemented as usual,but all individuals produced in this phase are stored as inputs of the training *** on design constraints verification,these individuals are labeled as“safe”or“unsafe”and their labels are saved as outputs of the training *** collecting enough data,an AdaBoost model is trained to evaluate the safety state of *** model is then used in the second stage to preliminarily assess new individuals,and unpromising ones are rejected without checking design *** method reduces unnecessary structural analyses,thereby shortens the optimization *** benchmark truss sizing optimization problems are solved using the proposed method to demonstrate its *** obtained results show that the CaDE finds good optimal designs with less structural analyses in comparison with the original DE and four other DE *** reduction rate of five examples ranges from 18 to over 50%.Moreover,the proposed method is applied to a real-size transmission tower design problem to exhibit its applicability in practice.

关键词： Structural optimization machine learning surrogate model differential evolution AdaBoost classifier