Journal of Science and Technique
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ENHANCING DRUG DISCOVERY THROUGH A META-PATH BASED OVERSAMPLING APPROACH FOR IMBALANCED DATA
Get PDFThis study proposes a new method to improve the efficiency of drug discovery by repurposing existing drugs, aiming to reduce the time and costs associated with traditional drug development processes, which can span 10 to 15 years and cost billions of dollars. Current approaches focus on leveraging heterogeneous data, such as drug-protein and disease-protein interactions, to construct complex networks that link drugs, proteins, and diseases. However, a significant challenge is the imbalance in data, where numerous unconfirmed potential drug-disease interactions (the majority class) outnumber approved drugs (the minority class), severely impacting the predictive performance of machine learning models. Previous attempts to address this issue have shown limited success. This study introduces a novel approach that integrates meta-paths in heterogeneous information networks with data balancing techniques to tackle this imbalance. Experimental results demonstrate that the proposed method enhances model performance and reliability in identifying new relationships between drugs and diseases. This research represents a promising advancement by leveraging network-based strategies and data balancing techniques to facilitate the rediscovery of drug applications, thereby potentially revolutionizing the pharmaceutical industry’s approach to drug development
A TYPE OF POST–QUANTUM CRYPTOGRAPHIC ALGORITHM
Get PDFThe article proposes a type of post–quantum cryptographic algorithm based on hash function and One–Time Pad cipher. Due to inheriting a property called “perfect secrecy” of the One-Time Pad cipher, the algorithms constructed according to the method proposed here can resist various types of attacks with the help of quantum computers. In addition to high security, algorithms of this type also have the ability to authenticate the origin and integrity of the encrypted messages. On the other hand, the one-time key for encryption/decryption is established for each individual message while the management and distribution of the shared secret key between the sender/encryptor and receiver/decryptor is performed similar to symmetric – key cryptosystems being applied in practice
ASSESSMENT OF IMPERVIOUS SURFACE CHANGES FROM MULTI-TEMPORAL LANDSAT DATA AND MACHINE LEARNING TECHNIQUES: A CASE STUDY IN HO CHI MINH CITY
Get PDFImpervious surface is an artificial surface that prevents water from seeping into the ground. Impervious surface is not only an indicator of the level of urbanization but also a key indicator of the quality of the urban environment. This article presents the results of an impervious surface classification in the Ho Chi Minh City area from multi-temporal Landsat image data. Three Landsat image scenes from 2010 - 2020, including Landsat 5 images taken on February 11, 2010, Landsat 8 images taken on February 9, 2015 and February 23, 2020 are used to classify land cover/land use, including impervious surface. Three machine learning algorithms (Random Forest, Support Vector Machine, Classification and Regression Tree) and maximum likelihood method are tested to select the algorithm with the highest accuracy. The results indicate that the Random Forest algorithm achieves the highest accuracy in classifying impervious surfaces, with an overall accuracy exceeding 93% and a Kappa coefficient of 0.915. The results received in the study also show an increase in impervious surface area in Ho Chi Minh City in the period 2010 - 2020. This is important information, helping managers in monitoring and planning urban areas
NAVIER SOLUTION FOR DEFLECTION AND STRESSES ANALYSIS OF FGM SANDWICH PLATE RESTING ON PASTERNAK ELASTIC FOUNDATION
Get PDFIn this article, the first-order shear deformation theory (FSDT) and Navier’s solution are used to establish analytical solutions for analyzing the deflection and stresses of FGM sandwich plate structures resting on a Pasternak elastic foundation. The top and bottom layers consist of functionally graded materials (P-FGM) that vary according to the exponential law along the thickness direction, while the core layer is composed of a porous material. The boundary condition of the plate is simply supported on all the edges, and the plate is subjected to a sinusoidal distributed load perpendicular to the mid-surface. The reliability of the model is validated through comparison with findings published in reputable journals. The effects of material parameters, geometric dimensions, foundation coefficients, and face-core-face thickness ratios on deflection and stress components of rectangular FGM sandwich plates are investigated in detail in parametric studies
DEVELOPING THE COMBINED KALMAN-EMD ALGORITHM TO PROCESS BLASTING SHOCKWAVE SIGNALS PROPAGATING IN A WATER MEDIUM
Get PDFIn experiments deploying underwater blast sensors, measured data is always disturbed, expressed as analog peaks in the obtained signal form. Except for pressure peak pmax, other parameters of an underwater explosion such as positive impulse I+, positive phase duration τ+, negative impulse I- and negative phase duration τ- are difficult or almost impossible to extract from this signal type. This article studies developing an algorithm called Kalman-EMD with the combination of Kalman filter and empirical mode decomposition for processing this signal type. The algorithm is applied in 6 data sets measuring the shockwave pressure of underwater explosions by PCB W138A05 sensors with the same condition that 184 grams of A-IX-2 explosive is detonated underwater. The results show that noise in signals is significantly eliminated. For the blasting parameters of processed signals, which can be compared with theory such as I+ and τ+, although it witnesses a small trade-off when errors of I+ enhance from about 3% to 6%, errors of τ+ are significantly decreased from about over 30% to only about 3%. Especially other pieces of information such as I- and τ- can be extracted from the processed signal so this trade-off can be acceptable. Hence, this algorithm can be applied to denoise and extract parameters from shockwave pressure signals of underwater explosions
ẢNH HƯỞNG CỦA THÔNG SỐ KẾT CẤU VÒI PHUN KIỂU AIR-BLAST LY TÂM ĐẾN CẤU TRÚC TIA PHUN
Get PDFViệc hình thành cấu trúc tia phun phù hợp với từng ứng dụng và điều kiện làm việc là mục đích chính trong các nghiên cứu phát triển vòi phun và hệ thống phun chất lỏng. Kết cấu vòi phun là một trong những yếu tố quan trọng nhất ảnh hưởng trực tiếp đến sự hình thành cấu trúc tia phun. Bài báo này trình bày kết quả nghiên cứu thực nghiệm bằng kỹ thuật chụp ảnh ngược sáng về ảnh hưởng của thông số kết cấu vòi phun kiểu air-blast ly tâm đến cấu trúc tia phun. Các thông số kết cấu được lựa chọn để khảo sát bao gồm đường kính buồng tạo xoáy chất lỏng, đường kính lỗ vòi phun và góc nghiêng cánh tạo xoáy dòng khí. Đối tượng nghiên cứu trong bài báo này là vòi phun kiểu air-blast ly tâm của máy chính trên thiết bị lặn ngầm. Cấu trúc tia phun được đặc trưng bởi các thông số chính bao gồm góc côn tia phun, chiều dài phân rã tia phun và kích thước của các giọt chất lỏng. Kết quả cho thấy, giọt chất lỏng được tạo ra trong tia phun có kích thước nhỏ hơn khi giảm DS hoặc tăng D0. Tại các vị trí cách lỗ vòi phun 45 mm, kích thước giọt chất lỏng đạt được sự ổn định và đồng đều với d10 và d32 thay đổi trong các khoảng tương tứng là từ 8,0 đến 17,7 mm và từ 12,0 đến 29,5 mm. Kết quả nghiên cứu là cơ sở khoa học để đề xuất giải pháp thay đổi kết cấu của vòi phun nhằm nâng cao tính năng chiến kỹ thuật của máy chính trên thiết bị lặn ngầm
SYNTHESIS AND CHARACTERIZATION OF POLYEPICHLOROHYDRIN DIOLS
Get PDFPolyepichlorohydrin (PECH) is a functional polymer with high value in energy materials. Cationic ring-opening polymerization of epichlorohydrin (ECH) with a diol initiator and Lewis or protic acids catalyst, proceeds through an activated monomer mechanism (AM) allowing control of the polymer's average molecular weight and polydispersity index. In the present investigation, PECH diol was synthesized under the catalysis of boron trifluoride etherate, with the ECH monomer:ethylene glycol as an initiator molar ratio of 1:0.045, achieving a low molecular weight nM = 1935 g/mol, low polydispersity index PDI = 1.25, predominantly in the linear chain configuration with the terminal hydroxyl group
DESIGN AND FABRICATION OF SHAPE MORPHING MAGNETO-IMPEDANCE MAGNETIC SENSOR
Get PDFThe magnetoimpedance (MI) effect is characterized by the alteration in the impedance of soft magnetic materials when subjected to a magnetic field while a high-frequency alternating current flows through them. In this study, we engineered two distinct sensor architectures utilizing amorphous FeCSi magnetic ribbon: a single-bar structure with the dimension of 10 mm × 90 μm × 20 μm and a meander structure consisting of 13 parallel single bars. These structures were miniaturized through advanced techniques combining laser engraving and chemical etching. The magnetic analysis reveals that the meander structure exhibits a pronounced dependency on the angle θ between the magnetic field and the sensor orientation, enhancing its soft magnetic properties by up to fivefold compared to the single-bar design. This enhancement might be attributed to a reduction in the demagnetization effect and shape anisotropy energy within the meander sensor. Furthermore, the analysis of the MI effect indicates that the resonance frequency remains unaffected by external magnetic fields for both sensor types. Notably, the meander sensor demonstrates exceptional MI ratio values exceeding 82%, representing a remarkable 24-fold increase over the 3.5% observed in the single-bar sensor. Additionally, the isotropy - quantified as the MI ratio's dependence on angle θ, and magnetic field sensitivity are significantly improved in the meander configuration. These advancements in soft magnetic and physical properties are correlated to the domain structure of the sensor, particularly its transverse magnetic permeability, as evidenced by micromagnetic simulations conducted using Mumax3. With its superior MI ratio, isotropy, and heightened magnetic field sensitivity, the meander-type magnetic field sensor presents substantial potential for applications across diverse fields, ranging from biological systems to specialized practical missions
RESEARCH SOLUTIONS FOR PRECAST CONCRETE REVETMENTS USING ALB-REBAR TO RETAIN CORAL SAND FOR OFFSHORE ISLANDS IN VIETNAM
Get PDFGravity revetment solutions are a popular choice for shore protection at atolls under the harsh conditions of ocean waves. The precast revetment option is preferred to reduce shipping costs for materials and ensure quick construction. This article studied precast concrete revetments with ALB composite material reinforcement and conducted experimental research to determine the shear resistance characteristics of coral sand and the friction characteristics of concrete materials with coral sand. Based on the experimental parameters, the authors calculated the stability of the ALB embankment structure against the effects of wave loads during storms. With experimental data obtained from coral sand samples prepared with equivalent density in the field, the results showed that the stability coefficient of the revetment is significantly higher than the one obtained from the traditional calculation concept
THE DYNAMIC CHARACTERISTICS OF SATURATED DENSE CORAL SAND SAMPLES
Get PDFConstructions placed on coral sand foundations on offshore islands are often subjected to wave and wind loads, which are cyclic dynamic loads. Therefore, a study on the behavior of coral sand under the effect of cyclic dynamic loads is necessary to evaluate the bearing capacity of the structures. This study is devoted to determining dense coral sand's dynamic parameters using Controls dynamic triaxial compression testing device under large deformation and different confining pressure conditions. Parameters analyzed in the present work include excess pore pressure, damping ratio, dynamic elastic modulus and dynamic shear modulus. In addition, to evaluate the correlation between static and dynamic elastic modulus of coral sand, the study conducted additional static triaxial compression experiments according to the consolidated undrained condition. The results showed that an increase in pore water pressure and a decrease in dynamic shear modulus as shear strain increases, while the damping ratio also increases. As the shear strain is less than 0.1%, the damping ratio showed minimal variation. The dynamic elastic modulus of the coral sand is approximately 1.5 times greater than its static elastic modulus