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Hybrid Design and Performance Tests of a Hovering Insect-inspired Flapping-wing Micro Aerial Vehicle

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Journal of Bionic Engineering 2016年第2期13卷 235-248页

作者： quoc-viet nguyen Woei Leong Chan Marco Debiasi Temasek Laboratories National University of Singapore Singapore 117411 Singapore

Hovering ability is one of the most desired features in Flapping-Wing Micro Air Vehicles （FW-MAVs）. This paper presents a hybrid design of flapping wing and fixed wing, which combines two flapping wings and two fixed wings to take advantage of the double wing clap-and-fling effect for high thrust production, and utilizes the fixed wings as the stabilizing surfaces for inherently stable hovering flight. Force measurement shows that the effect of wing clap-and-fling significantly enhances the cycle-averaged vertical thrust up to 44.82% at 12.4 Hz. The effect of ventral wing clap-and-fling due to presence of fixed wings produces about 11% increase of thrust-to-power ratio, and the insect-inspired FW-MAV can produce enough cycle-averaged vertical thrust of 14.76 g for lift-offat 10 Hz, and 24 g at maximum frequency of 12.4 Hz. Power measurement indicates that the power consumed for aerodynamic forces and wing inertia, and power loss due to gearbox friction and mechanism inertia was about 80% and 20% of the total input power, respectively. The proposed insect-inspired FW-MAV could endure three-minute flight, and demonstrate a good flight performance in terms of vertical take-off, hovering, and control with an onboard 3.7 V-70 mAh LiPo battery and control system.

关键词： insect-inspired flapping wing hovering clap-and-fling MAV vertical takeoff

Heterogeneous decentralised machine unlearning with seed model distillation

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 608-619页

作者： Guanhua Ye Tong Chen quoc viet Hung nguyen Hongzhi Yin School of Information Technology and Electrical Engineering The University of QueenslandSt LuciaQueenslandAustralia School of Information and Communication Technology Griffith UniversityBrisbaneQueenslandAustralia

As some recent information security legislation endowed users with unconditional rights to be forgotten by any trained machine learning model,personalised IoT service pro-viders have to put unlearning functionality into their *** most straight-forward method to unlearn users'contribution is to retrain the model from the initial state,which is not realistic in high throughput applications with frequent unlearning *** some machine unlearning frameworks have been proposed to speed up the retraining process,they fail to match decentralised learning scenarios.A decentralised unlearning framework called heterogeneous decentralised unlearning framework with seed(HDUS)is designed,which uses distilled seed models to construct erasable en-sembles for all ***,the framework is compatible with heterogeneous on-device models,representing stronger scalability in real-world *** experiments on three real-world datasets show that our HDUS achieves state-of-the-art performance.

关键词： data mining data privacy machine learning

Verification of Beam Models for Ionic Polymer-Metal Composite Actuator

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Journal of Bionic Engineering 2009年第3期6卷 232-238页

作者： Hoon Cheol Park quoc viet nguyen Jang Woo Lee Young Tai Yoo Artificial Muscle Research Center Konkuk University Department of Advanced Technology Fusion Konkuk University Department of Materials Chemistry and Engineering Konkuk University

Ionic Polymer-Metal Composite (IPMC) can work as an actuator by applying a few voltages.A thick IPMC actuator,where Nafion-117 membrane was synthesized with polypyrrole/alumina composite filler,was analyzed to verify the equivalent beam and equivalent bimorph beam *** blocking force and tip displacement of the IPMC actuator were measured with a DC power supply and Young's modulus of the IPMC strip was measured by bending and tensile tests *** calculated maximum tip displacement and the Young's modulus by the equivalent beam model were almost identical to the corresponding measured *** element analysis with thermal analogy technique was utilized in the equivalent bimorph beam model to numerically reproduce the force-displacement relationship of the IPMC *** results by the equivalent bimorph beam model agreed well with the force-displacement relationship acquired by the measured *** is confirmed that the equivalent beam and equivalent bimorph beam models are practically and effectively suitable for predicting the tip displacement,blocking force and Young's modulus of IPMC actuators with different thickness and different composite of ionic polymer membrane.

关键词： jonic polymer-metal composite beam model displacement force

Improvement of Artificial Foldable Wing Models by Mimicking the Unfolding/Folding Mechanism of a Beetle Hind Wing

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Journal of Bionic Engineering 2010年第2期7卷 134-141页

作者： Azhar Muhammad quoc viet nguyen Hoon Cheol Park Do Y.Hwang Doyoung Byun Nam Seo Goo Department of Advanced Technology Fusion Konkuk University National Research Laboratory for Biomimetics and Microsystems Konkuk University Artificial Muscle Research Center Konkuk University Departmenet of Aerospace Engineering Konkuk University

In an attempt to realize a flapping wing micro-air vehicle with morphing wings, we report on improvements to our previousfoldable artificial hind *** hinges, which were implemented to mimic the bending zone of a beetle hind wing, weremade of small composite hinge plates and tiny aluminum *** buck-tails of rivets were flared after the hinge plates wereassembled with the rivets so that the folding/unfolding motions could be completed in less time, and the straight shape of theartificial hind wing could be maintained after *** and unfolding actions were triggered by electrically-activatedShape Memory Alloy (SMA) *** wing folding, the actuation characteristics of the SMA wire actuator were modifiedthrough heat *** a series of flapping tests, we confirmed that the artificial wings did not fold back and arbitrarilyfluctuate during the flapping motion.

关键词： hind wing unfolding folding shape memory alloy folding ratio artificial wing

Stable Vertical Takeoff of an Insect-Mimicking Flapping-Wing System Without Guide Implementing Inherent Pitching Stability

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Journal of Bionic Engineering 2012年第4期9卷 391-401页

作者： Hoang Vu Phan quoc viet nguyen Quang Tri Truong Tien Van Truong Hoon Cheol Park Nam Seo Goo Doyoung Byun Min Jun Kim Department of Advanced Technology Fusion Konkuk University Seoul 143-701 Korea Department of Aerospace Engineering Konkuk University Seoul 143-701 Korea Department of Mechanical Engineering Sungkyunkwan University Seoul 143-701 Korea Department of Mechanical Engineering and Mechanics Drexel University Philadelphia USA

We briefly summarized how to design and fabricate an insect-mimicking flapping-wing system and demonstrate how to implement inherent pitching stability for stable vertical takeoff. The effect of relative locations of the Center of Gravity （CG） and the mean Aerodynamic Center （AC） on vertical flight was theoretically examined through static force balance considera- tion. We conducted a series of vertical takeoff tests in which the location of the mean AC was determined using an unsteady Blade Element Theory （BET） previously developed by the authors. Sequential images were captured during the takeoff tests using a high-speed camera. The results demonstrated that inherent pitching stability for vertical takeoff can be achieved by controlling the relative position between the CG and the mean AC of the flapping system.

关键词： beetle flapping-wing system insect-mimicking insect flight inherent pitching stability vertical takeoff

Privacy-preserving explainable AI: a survey

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Science China(Information Sciences) 2024年

作者： Thanh Tam nguyen Thanh Trung HUYNH Zhao REN Thanh Toan nguyen Phi Le nguyen Hongzhi YIN quoc viet Hung nguyen School of Information and Communication Technology Griffith University School of Computer and Communication Sciences Ecole Polytechnique Federale de Lausanne Faculty of Mathematics and Computer Science University of Bremen Faculty of Information Technology HUTECH University Department of Computer Science Hanoi University of Science and Technology School of Electrical Engineering and Computer Science The University of Queensland

As the adoption of explainable AI (XAI) continues to expand, the urgency to address its privacy implications intensifies. Despite a growing corpus of research in AI privacy and explainability, there is little attention on privacy-preserving model explanations. This article presents the first thorough survey about privacy attacks on model explanations and their countermeasures. Our contribution to this field comprises a thorough analysis of research papers with a connected taxonomy that facilitates the categorization of privacy attacks and countermeasures based on the targeted explanations. This work also includes an initial investigation into the causes of privacy leaks. Finally, we discuss unresolved issues and prospective research directions uncovered in our analysis. This survey aims to be a valuable resource for the research community and offers clear insights for those new to this domain. To support ongoing research, we have established an online resource repository, which will be continuously updated with new and relevant findings.

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Fresh and hardened properties of high-performance fiber-reinforced concrete containing fly ash and rice husk ash:Influence of fiber type and content

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1621-1632页

作者： nguyen-Trong HO viet quoc DANG Minh-Hieu nguyen Chao-Lung HWANG Trong-Phuoc HUYNH Faculty of Civil Engineering VSB-Technical University of OstravaOstrava-Poruba 70800Czech Republic Faculty of Bridge and Road Construction Mientrung University of Civil Engineering(MUCE)Tuy Hoa City 56100Vietnam Vinh Long Department of Construction Vinh Long City 85000Vietnam Taiwan Building Technology Center Taiwan University of Science and TechnologyTaipei 10607China Faculty of Civil Engineering College of EngineeringCan Tho UniversityCan Tho City 94000Vietnam

Although fibers are used only infrequently as an additive in concrete in the construction industry,fiberenhanced concrete is known to provide a wide range of advantages over conventional *** main objective of this study was to investigate the influences of fiber type and content on the mechanical properties and durability of highperformance fiber-reinforced concrete(HPFRC)designed using a novel densified mixture design algorithm with fly ash and rice husk *** types of fiber,including polypropylene(PP)fiber,steel fiber(SF),and hybrid fiber(HF),were *** on the results,the inclusion of fibers decreased HPFRC flowability,regardless of fiber *** the compressive strength of HPFRC with 1.6%PP fiber content was 11.2%below that of the reference HPFRC specimen at 91 d of curing age,the 91-d compressive strengths of both SF and HF-enhanced HPFRC specimens were significantly better than that of the reference HPFRC ***,the HPFRC specimens incorporating SF and HF both exhibited better splitting tensile and flexural strengths as well as less drying shrinkage than the HPFRC specimens incorporating PP ***,the fiber-enhanced specimens,especially those with added SF,registered less surface electrical resistivity and greater vulnerability to chloride ion penetration than the reference HPFRC specimen.

关键词： high-performance fiber-reinforced concrete fly ash rice husk ash durability mechanical strength

Scale and scope economies in small household rice farming in vietnam

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Journal of Integrative Agriculture 2021年第12期20卷 3339-3351页

作者： viet-Ngu HOANG Trung Thanh nguyen Clevo WILSON Thong quoc HO Uttam KHANAL School of Economics and Finance Queensland University of TechnologyBrisbaneQLD 4000Australia Institute for Environmental Economics and World Trade Leibniz University HannoverHannover 30167Germany University of Economics Ho Chi Minh City Ho Chi Minh City 72516Vietnam Agriculture Victoria Department of JobsPrecincts and RegionsHorshamVIC 3400Australia

The vietnamese agricultural sector has experienced a dramatic structural change based on increased specialization in rice ***,small-scale rice-farmers have continued to grow multiple crops,especially in less developed *** the literature advocates crop diversification for reasons of both economic and ecological sustainability,there lacks empirical evidence as to whether crop diversification brings efficiency and productivity gains to small *** present study is the first applications of the input-oriented stochastic distance function approach in estimating scale and scope economies using data of multi-crop farming households in *** find strong evidence of product-specific economies of *** economies are also present for rice,vegetable,and other annual crop *** suggests that crop diversification enhances efficiency and ***,there still exists significant technical inefficiency in crop production,indicating opportunities to expand farm output at the existing level of inputs and *** specifically,our empirical results indicate that it is desirable to expand vegetable and other annual crop production in mountainous areas while rice cultivation can be further expanded in delta and coastal regions.

关键词： input distance function stochastic frontier economies of scope economies of scale product-specific

Aerodynamic force generation of an insect-inspired flapper actuated by a compressed unimorph actuator

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Chinese Science Bulletin 2009年第16期54卷 2871-2879页

作者： nguyen quoc-viet PARK Hoon C GOO Nam S BYUN Doyoung Department of Advanced Technology Fusion Konkuk University National Research Laboratory for Biomimetics and Intelligent Microsystems Konkuk University Department of Aerospace Engineering Konkuk University

We examined experimentally the flapping performance in terms of aerodynamic force generation of an insect-inspired flapper actuated by both of original LIPCA and compressed LIPCA. Flapping tests for two artificial wing shapes of horse botfly and hawk moth were conducted at the wing rotation angle of 60° and a flapping frequency range from 6 Hz to 12 Hz to find the optimum flapping frequency and to investigate the effect of compressed LIPCA and wing shape on the force generation. Flapping tests in the vacuum were also undertaken to measure the induced inertia force. The aerodynamic force was calculated by subtracting the inertia force from the total force measured in the air. It was found that the average inertia force was relatively small when compared with the average total force. The use of the compressed LIPCA could significantly improve the flapping angle of the flapper from 110° to 130° (18.2% increase) resulting in 24.5% increase in the average aerodynamic force. It was also found that flapper with hawk moth wings could produce larger force than the flapper with horse botfly wings.

关键词：空气动力驱动器插板压缩部队昆虫压电片单层