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Tan Dat Trinh,Pham The Bao,Le Nhi Lam Thuy,Ikuko Shimizu,김진영,Pham The Bao 한국전기전자학회 2019 전기전자학회논문지 Vol.23 No.2
In this study, a novel hierarchical approach is investigated to extract coronary vessel from X-ray angiogram. First, we propose to combine Decimation-free Directional Filter Bank (DDFB) and Homographic Filtering (HF)in order to enhance X-ray coronary angiographic image for segmentation purposes. Because the blood vesselensures that blood flows in only one direction on vessel branch, the DDFB filter is suitable to be used toenhance the vessels at different orientations and radius. In the combination with HF filter, our method cansimultaneously normalize the brightness across the image and increases contrast. Next, a coarse-to-finestrategy for iterative segmentation based on Otsu algorithm is applied to extract the main coronary vessels indifferent sizes. Furthermore, we also propose a new approach to segment very small vessels. Specifically,based on information of the main extracted vessels, we introduce a new method to extract junctions on thevascular tree and level of nodes on the tree. Then, the window based segmentation is applied to locate andextract the small vessels. Experimental results on our coronary X-ray angiography dataset demonstrate thatthe proposed approach can outperform standard method and attain the accuracy of 71.34%.
Physical properties improvement of polymer membrane material by incorporation with inorganic dopant
( Pham Tan Thong ),정호영 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
The polymer membrane in the study is reinforced by raising hydrophilicity on structure due to incorporation with hydrophilic inorganic material. Due to the addition of hydrophilic functional groups, protons are easily appealed and transported through membrane. Therefore, electrochemical reaction in battery/fuel cell can take place at faster kinetic and thus be expected to perform with high cell efficiency. As a result, the inorganic-doped polymer membrane shows enhancement in physical properies such as water uptake, ion exchange capacity, and proton conductivity. To confirm improved properties and contribution of inorganic dopant, structural analyses are carried out using scanning electron microscopy, Fourier transform infrared spectroscopy, and thermo gravimetric analysis. The accomplishment of this work confirms the method for improving hydrocarbon membrane by inorganic/ organic hybridizing preparation to make the electrolyte material more promising for battery/fuel cell application.
Preliminary study for developing a flying-fish-mimicking swimming robot
Tan-Hanh Pham(팜탄한),Hoon Cheol Park(박훈철) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Flying fish is the only fish that can leap from the water and glide in the air. We have been performing a basic study for developing a swimming robot to mimic the underwater leap of the flying fish. In this paper, we present our research progress in the propulsion system design, thrust measurement, drag coefficient measurement, and underwater-leap speed estimation. The measured average thrust produced by the tail-beating thruster was about 0.88 N at about 11 Hz. The drag coefficient was measured and predicted to be 0.02. From a vertical underwater-leap test using the buoyancy force, we have confirmed that it is possible to jump from the water into the air when a swimming robot can reach the water surface at about 2.5 m/s.
Pham Ngoc Son,Tran Trung Duy,Pham Viet Tuan,Tan-Phuoc Huynh Electronics and Telecommunications Research Instit 2023 ETRI Journal Vol.45 No.1
We propose short packet communication in an underlay cognitive radio network assisted by an intelligent reflecting surface (IRS) composed of multiple reconfigurable reflectors. This scheme, called the IRS protocol, operates in only one time slot (TS) using the IRS. The IRS adjusts its phases to give zero received cumulative phase at the secondary destination, thereby enhancing the end-to-end signal-to-noise ratio. The transmitting power of the secondary source is optimized to simultaneously satisfy the multi-interference constraints, hardware limitations, and performance improvement. Simulation and analysis results of the average block error rates (BLERs) show that the performance can be enhanced by installing more reconfigurable reflectors, increasing the blocklength, lowering the number of required primary receivers, or sending fewer information bits. Moreover, the proposed IRS protocol always outperforms underlay relaying protocols using two TSs for data transmission, and achieves the best average BLER at identical transmission distances between the secondary source and secondary destination. The theoretical analyses are confirmed by Monte Carlo simulations.
Evaluation of physicochemical and biological properties of python fat (Python bivittatus)
Pham Thi Quyen,Le Pham Tan Quoc 한국식품저장유통학회 2023 한국식품저장유통학회지 Vol.30 No.5
The main aim of this study was to determine python fat’s several physicochemical properties, including dimensions, color, structure, acid value (AV), saponification value (SV), density, and recovery efficiency. The optimum yield obtained was approximately 80.40% at 180℃ for 60 min with an AV of 0.3366 and SV of 179.56 mg KOH/g. Fatty acids, comprising oleic acid (72.462%), palmitic acid (26.243%), linolenic acid (0.835%), and myristic acid (0.459%), were identified using gas chromatography-mass spectrometry (GC-MS). The python fat had a very weak antioxidant capacity and almost no antibacterial ability with gram-positive (Staphylococcus aureus - ATCC 25923 and Bacillus cereus - ATCC 10876) and gram- negative (Escherichia coli - ATCC 25922 and Salmonella enterica - ATCC 35664) bacteria (used the paper disc diffusion method for antibiotic susceptibility testing). Moreover, python fat is considered to be very resistant to high temperatures.
Design and test of a tail-beating propulsion system for the robotic flying fish
Tan Hanh Pham(팜탄한),Hoang Vu Phan(판호앙부),Hoon Cheol Park(박훈철) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
Flying fish are unique underwater animals that can escape from water to air producing large thrusts by undulating their caudal fins and creating relatively fast swimming speed of 10 m/s. The average mass of flying fish is about 30 gram and their lengths are 15 cm to 50 cm. As the first step of developing a robotic system that can mimic the outstanding feature of flying fish, we first designed and tested an electromagnetic motor-based propulsion system that can create a fast tail-beating motion and produce a thrust. The required torque of the motor was calculated considering the gear ratio and the applied torque from tail based on the added mass model. Experimental results obtained from measurement showed that propulsion system could generate a cycle average thrust of 0.88 N at a tail beating frequency of about 11 Hz when 12 V is applied to the motor. The propulsion system will be further improved for a larger thrust generation and robotic fish will be designed and fabricated, which hosts the propulsion system.