對潛戰

Navy International誌,유삼남 해군대학 1982 海洋戰略 Vol.- No.16

Dynamic Modulus of Three-Layer Boards with Different Furnish and Shelling Ratio

Muhammad Navis Rofii,Tibertius Agus Prayitno,Shigehiko Suzuki 한국목재공학회 2016 목재공학 Vol.44 No.2

This aims of this study were to investigate the relationship between non-destructive evaluation (NDE) and actual bending properties of particleboard, and to predict the bending properties of three-layer particleboard. Three kinds of raw materials, i.e. Hinoki (Chamaecyparis obtusa Endl.) strand, knife-milled Douglas-fir (Pseudotsuga manziesii (Mirb) Franco), and hammer-milled matoa (Pometia spp.) obtained from wooden industry, were utilized as furnish for experimental panel with methylene diphenyl diisocyanate (MDI) resin as binder. The NDE test was conducted by hit sounds using an FFT analyzer according to the spectrum peak of wave frequency, while the static bending test was conducted according to JIS A-5908. The results reveal that the dynamic Young’s modulus as an NDE test has a potential for being used to predict the elastic bending of particleboards by a specific equation for adjusting its proper values. The values of NDE and static test are significantly different with a deviation range at 3-20%. The bending stiffness of three-layer particleboards manufactured from different wood species is predictable by observing the bending stiffness of two elements based on the thickness of its layers. The predicted values of bending stiffness and static test are significantly different with a deviation range at 5-24%.

Active control of three-phase CNT/resin/fiber piezoelectric polymeric nanocomposite porous sandwich microbeam based on sinusoidal shear deformation theory

B. Rousta Navi,M. Mohammadimehr,A. Ghorbanpour Arani 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.6

Vibration control in mechanical equipments is an important problem where unwanted vibrations are vanish or at least diminished. In this paper, free vibration active control of the porous sandwich piezoelectric polymeric nanocomposite microbeam with microsensor and microactuater layers are investigated. The aim of this research is to reduce amplitude of vibration in micro beam based on linear quadratic regulator (LQR). Modified couple stress theory (MCST) according to sinusoidal shear deformation theory is presented. The porous sandwich microbeam is rested on elastic foundation. The core and face sheet are made of porous and three-phase carbon nanotubes/resin/fiber nanocomposite materials. The equations of motion are extracted by Hamilton’s principle and then Navier’s type solution are employed for solving them. The governing equations of motion are written in space state form and linear quadratic regulator (LQR) is used for active control approach. The various parameters are conducted to investigate on the frequency response function (FRF) of the sandwich microbeam for vibration active control. The results indicate that the higher length scale to the thickness, the face sheet thickness to total thickness and the considering microsensor and microactutor significantly affect LQR and uncontrolled FRF. Also, the porosity coefficient increasing, Skempton coefficient and Winkler spring constant shift the frequency response to higher frequencies. The obtained results can be useful for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

Using Harmony Clustering for Haplotype Reconstruction from SNP fragments

Saman Poursiah Navi 보안공학연구지원센터 2013 International Journal of Bio-Science and Bio-Techn Vol.5 No.5

Variability of Measurement of Patellofemoral Indices with Knee Flexion and Quadriceps Contraction: An MRI-Based Anatomical Study

( Edward Laugharne ),( Navi Bali ),( Sanjay Purushothamdas ),( Faris Almallah ),( Rik Kundra ) 대한슬관절학회 2016 대한슬관절학회지 Vol.28 No.4

Purpose: The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). Materials and Methods: MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. Results: With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31. Conclusions: MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction.

Efficient programmable power-of-two scaler for the three-moduli set {2^n+p, 2ⁿ - 1, 2ⁿ⁺¹ - 1}

Taheri, MohammadReza,Navi, Keivan,Molahosseini, Amir Sabbagh Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.4

Scaling is an important operation because of the iterative nature of arithmetic processes in digital signal processors (DSPs). In residue number system (RNS)-based DSPs, scaling represents a performance bottleneck based on the complexity of intermodulo operations. To design an efficient RNS scaler for special moduli sets, a body of literature has been dedicated to the study of the well-known moduli sets {2ⁿ - 1, 2ⁿ, 2ⁿ + 1} and {2ⁿ, 2ⁿ - 1, 2ⁿ⁺¹ - 1}, and their extension in vertical or horizontal forms. In this study, we propose an efficient programmable RNS scaler for the arithmetic-friendly moduli set {2^n+p, 2ⁿ - 1, 2ⁿ⁺¹ - 1}. The proposed algorithm yields high speed and energy-efficient realization of an RNS programmable scaler based on the effective exploitation of the mixed-radix representation, parallelism, and a hardware sharing technique. Experimental results obtained for a 130 nm CMOS ASIC technology demonstrate the superiority of the proposed programmable scaler compared to the only available and highly effective hybrid programmable scaler for an identical moduli set. The proposed scaler provides 43.28% less power consumption, 33.27% faster execution, and 28.55% more area saving on average compared to the hybrid programmable scaler.

Free vibration of an annular sandwich plate with CNTRC facesheets and FG porous cores using Ritz method

Emdadi, Mohsen,Mohammadimehr, Mehdi,Navi, Borhan Rousta Techno-Press 2019 Advances in nano research Vol.7 No.2

In this article, the free vibration analysis of annular sandwich plates with various functionally graded (FG) porous cores and carbon nanotubes reinforced composite (CNTRC) facesheets is investigated based on modified couple stress theory (MCST) and first order shear deformation theories (FSDT). The annular sandwich plate is composed of two face layers and a functionally graded porous core layer which contains different porosity distributions. Various approaches such as extended mixture rule (EMR), Eshelby-Mori-Tanaka (E-M-T), and Halpin-Tsai (H-T) are used to determine the effective material properties of microcomposite circular sandwich plate. The governing equations of motion are extracted by using Hamilton's principle and FSDT. A Ritz method has been utilized to calculate the natural frequency of an annular sandwich plate. The effects of material length scale parameters, boundary conditions, aspect and inner-outer radius ratios, FG porous distributions, pore compressibility and volume fractions of CNTs are considered. The results are obtained by Ritz solutions that can be served as benchmark data to validate their numerical and analytical methods in the future work and also in solid-state physics, materials science, and micro-electro-mechanical devices.

P-62 : Press temperature and mat moisture content effects on temperature and vapor pressure behaviors of recycled-wood particleboard during hot pressing

( Shigehiko Suzuki ),( Muhammad Navis Rofii ),( Shuto Kubota ),( Hikaru Kobori ),( Yoichi Kojima ) 韓國木材工學會 2015 한국목재공학회 학술발표논문집 Vol.2015 No.-

Variability of Measurement of Patellofemoral Indices with Knee Flexion and Quadriceps Contraction: An MRI-Based Anatomical Study

Edward Laugharne, FRCS,Navi Bali, FRCS,Sanjay Purushothamdas, FRCS,Faris Almallah, FRCR,Rik Kundra, FRCS 대한슬관절학회 2016 대한슬관절학회지 Vol.28 No.4

purpose: The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI).Materials and Methods: MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured.results: With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31.conclusions: MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction.

Multi-models of Educational Data Mining for Predicting Student Performance in Mathematics: A Case Study on High Schools in Cambodia

Phauk Sokkhey,Sin Navy,Ly Tong,Takeo Okazaki 대한전자공학회 2020 IEIE Transactions on Smart Processing & Computing Vol.9 No.3

Education is crucial for the development of any country. Analysis of education datasets requires effective algorithms to extract hidden information and gain the fruitful results to improve academic performance. Multiple models were used to maximize the contribution to the education environment. In this study, we used the spot-checking algorithm to compare these methods and find the most effective method. We propose three main classes of education research tools: a statistical analysis method, machine learning algorithms, and a deep learning framework. The data were obtained from many high schools in Cambodia. We introduced feature selection techniques to figure out the informative features that affect the future performance of students in mathematics. The proposed ensemble methods of tree-based classifiers provide satisfiying results, and in that, random forest algorithm generates the highest accuracy and the lowest predictive mean squared error, thus showing potential in this prediction and classification problem. The results from this work can be used as recipe and recommendation for mining various material settings in improving high school student performance in Cambodia.