Application of Hamilton variational principle for vibration of fluid filled structure

Khaled Mohamed Khedher,Muzamal Hussain,Rizwan Munir,Saleh Alsulamy,Ayed Eid Alluqmani Techno-Press 2023 Advances in nano research Vol.15 No.5

Vibration investigation of fluid-filled three layered cylindrical shells is studied here. A cylindrical shell is immersed in a fluid which is a non-viscous one. Shell motion equations are framed first order shell theory due to Love. These equations are partial differential equations which are usually solved by approximate technique. Robust and efficient techniques are favored to get precise results. Employment of the wave propagation approach procedure gives birth to the shell frequency equation. Use of acoustic wave equation is done to incorporate the sound pressure produced in a fluid. Hankel's functions of second kind designate the fluid influence. Mathematically the integral form of the Lagrange energy functional is converted into a set of three partial differential equations. It is also exhibited that the effect of frequencies is investigated by varying the different layers with constituent material. The coupled frequencies changes with these layers according to the material formation of fluid-filled FG-CSs. Throughout the computation, it is observed that the frequency behavior for the boundary conditions follow as; clamped-clamped (C-C), simply supported-simply supported (SS-SS) frequency curves are higher than that of clamped-simply (C-S) curves. Expressions for modal displacement functions, the three unknown functions are supposed in such way that the axial, circumferential and time variables are separated by the product method. Computer software MATLAB codes are used to solve the frequency equation for extracting vibrations of fluid-filled.

Purification, Characterization, and Partial Primary Sequence of a Major-Maltotriose-producing α-Amylase, ScAmy43, from Sclerotinia sclerotiorum

( Ben Abdelmalek-Khedher Imen ),( Maria Camino Urdaci ),( Ferid Limam ),( Jean Marie Schmitter ),( M. Nejib Marzouki ),( Philippe Bressollier ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.9

Statistical Method for Real-Time Detection of Travel Time Outliers

Moataz Bellah Ben Khedher(모타즈 케들러),Duk Geun Yun(윤덕근),Jung Gon Sung(성정곤) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.10

도로 이용자나 도로관리자에게 교통 분석이나 경로 선택에 있어 통행시간은 중요한 정보이다. 그러나 수집된 개별 통행시간에 이상치(outlier)가 존재함으로 인해서 수집된 통행시간 정보는 항상 그 값을 대표한다고 보기에 한계가 존재한다. 통행시간 추정을 위한 기존의 방법은 방대한 과거 데이터를 사용하여 계수 추정(parametric models)을 위한 다양한 모형을 사용하였다. 기존 전통적인 방법에서 Outlier를 검지하고, 처리하여 신뢰성 있는 통행시간을 추정하기 위해 본 연구에서는 Non-parametric outlier filtering 방법인 Outskewer 방법을 제안하였다. Outskewer 적용시 기존에 사용하던 Sliding Window 방법 대신 분석할 데이터양이 충분하지 못한 구간에서는 알고리즘이 충분히 분석할 수 있는 데이터양을 확보할 수 있도록 직전의 데이터를 더 추가할 수 있는 Extendable Moving Window 기법을 적용하였다. 제안된 모형을 평가하기 위하여 다차로 도로에서 수집된 DSRC(Dedicated Short Range Communication)를 사용하였다. 모형 평가시 통행시간의 참 값(ground truth)의 부재로 인하여 그래프와 통계의 유의성 검증을 통하여 모형을 평가하였다. 통행시간에 대한 통계적 검증결과 최대 상대 오차(maximum relative error)는 20%보다 적게 나타났고, Correct Classification Rate는 90% 이상으로 나타났다. 결과를 고려할 때 제안된 방법론은 통행시간 추정 시 Outlier를 처리하는데 있어서 기존의 방법론보다 더 신뢰성 있게 나타나 도로이용자와 관리자에게 더 정확한 통행시간을 제공할 수 있을 것으로 기대하였다. Travel time information plays a crucial role in supporting road users and transportation agencies with precise data that can be used for traffic analysis and route choosing. However, the acquired data does not always show a representative value of the travel time due to the presence of outliers. The outlier must hence be removed, and various techniques of outlier filtering rely on parametric models that require extensive historical data for parametric estimation. In this study, we propose a non-parametric outlier filtering method for a reliable travel time estimation. As part of the study, an Outskewer method was adopted and enhanced to overcome its deficiency and to be able to detect outliers in online mode. Dedicated short-range communication probe data, collected from a multi-lane highway, was used for the quality assessment. In lack of ground truth records, the performance of the proposed algorithm was evaluated qualitatively, based on graphs and quantitatively using the confidence interval method. Visual inspection of graphical results shows the satisfactory performance of the present method. The hypothesis test for travel time data quality indicates a maximum relative error of less than 20% and a percentage correct classification of higher than 90%. Hence, the proposed methodology can serve as an alternative to other parametric methods used for travel time outlier treatments and can support the delivery of more accurate information for road travelers and transportation practitioners.

Study on Enhancement of TRANSGUIDE Outlier Filter Method under Unstable Traffic Flow for Reliable Travel Time Estimation

Moataz Bellah Ben Khedher(모타즈 케들러 ),Duk Geun Yun(윤덕근) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.3

신뢰성 있는 통행시간 예측을 위해 DSRC로부터 수집된 통행시간에서의 이상치(outlier) 필터링은 필수이다. 통행시간 예측을 위해 사용되는 보편적 기법인 TRANSGUIDE는 특정 분석 시간동안 통행시간의 변동이 크게 발생하는 조건에서 수집데이터의 이상치 제거를 효율적으로 처리하지 못하는 문제점이 존재한다. 이에 본 연구에서는 TRANSGUIDE의 한계점을 보완할 수 있는 알고리즘을 제안하고자 한다. TRANSGUIDE가 특정 분석 시간대 충분한 데이터 관측이 어려울 경우 Median Absolute Deviation(MAD)를 이용하여 이상치 제거를 위한 새로운 유효 분석 영역을 설정하였다. 새로운 분석 영역설정 후 특정 시간대 교통 조건하에서 최대 허용 가능한 이상치를 고려한 변수 α, β를 제안하였다. 변수 α, β를 추정하기 위해 과거 데이터와 도로 구간의 특성을 반영하였다. 개발된 알고리즘은 수도권 일반국도 3호선, 2013년 1월 1달간 DSRC 데이터가 존재하는 다차로 일반국도에 적용하였다. 누적상대도수를 이용하여 모형의 정산 수행 후 성능에 대해 정량적 평가를 수행하였다. 개발된 알고리즘은 기존의 TRANSGUIDE가 특정 조건, 즉 일정 분석 시간동안 교통 조건이 급하게 변동되는 구간에서 이상치 제거에 취한한 점을 보완하는 것으로 판단되었다. TRANSGUDIDE가 특정 조건에서 통행시간 예측이 어려울 경우 본 개발 알고리즘은 활용될 것으로 판단한다. Filtering the data for travel time records obtained from DSRC probes is essential for a better estimation of the link travel time. This study addresses the major deficiency in the performance of TRANSGUIDE in removing anomalous data. This algorithm is unable to handle unstable traffic flow conditions for certain time intervals, where fluctuations are observed. In this regard, this study proposes an algorithm that is capable of overcoming the weaknesses of TRANSGUIDE. If TRANSGUIDE fails to validate sufficient number of observations inside one time interval, another process specifies a new validity range based on the median absolute deviation (MAD), a common statistical approach. The proposed algorithm suggests the parameters, α and β, to consider the maximum allowed outlier within a one-time interval to respond to certain traffic flow conditions. The parameter estimation relies on historical data because it needs to be updated frequently. To test the proposed algorithm, the DSRC probe travel time data were collected from a multilane highway road section. Calibration of the model was performed by statistical data analysis through using cumulative relative frequency. The qualitative evaluation shows satisfactory performance. The proposed model overcomes the deficiency associated with the rapid change in travel time.

Generalized Linear Models to Identify the Impact of Road Geometric Design Features on Crash Frequency in Rural Roads

Moataz Bellah Ben Khedher,윤덕근 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.3

One of the first steps in improving the road network is to implement a traffic safety program and identify problematic road segments where local risk factors increase the likelihood of vehicular accidents. Numerous studies have attempted to identify both the geometric and traffic features of road segments that may lead to increased risk. The statistical models linking the number of accidents at road sites over a unit of time and the characteristics of these sites contribute to highlighting and quantifying the impact of the development of road infrastructure on the risk of accidents. The evaluation and selection of the best-fit model are usually carried out using an information criterion. The main purpose of this research is to propose a comparative assessment framework to support the evaluation task during the process of modeling crash frequency. Performance evaluation was conducted using additional approaches, specifically data splitting and rootograms. In this study, we focus on Korean rural road accident records. Six generalized linear models were applied, and their performance was compared to determine the best-fitting statistical model. According to each model assessment method used, the negative binomial hurdle model showed the best performance among all the investigated models.

Enhancement of TRANSGUIDE Outlier Filter Method under Unstable Traffic Flow for Reliable Travel Time Estimation

Moataz Bellah Ben Khedher,윤덕근 한국도로학회 2017 한국도로학회 학술대회 발표논문 초록집 Vol.2017 No.03

A system of several fraction laws for the identification of rotating response of FG shell

Yahya, Ahmad,Hussain, Muzamal,Khadimallah, Mohamed A.,Khedher, Khaled Mohamed,Al-Basyouni, K.S.,Ghandourah, Emad,Banoqitah, Essam Mohammed,Alshoaibi, Adil Techno-Press 2022 Advances in concrete construction Vol.13 No.3

The problem is formulated by applying the Kirchhoff's conception for shell theory. The longitudinal modal displacement functions are assessed by characteristic beam ones meet clamped-clamped end conditions applied at the shell edges. The fundamental natural frequency of rotating functionally graded cylindrical shells of different parameter versus ratios of length-to-diameter and height-to-diameter for a wide range has been reported and investigated through the study with fractions laws. The frequency first increases and gain maximum value with the increase of circumferential wave mode. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The trigonometric frequencies are lower than that of exponential and polynomial frequencies. Stability of a cylindrical shell depends highly on these aspects of material. More the shell material sustains a load due to physical situations, the more the shell is stable. Any predicted fatigue due to burden of vibrations is evaded by estimating their dynamical aspects.

Backward and forward rotating of FG ring support cylindrical shells

Mohamed A. Khadimallah,Muzamal Hussain,Khaled Mohamed Khedher,Muhammad Nawaz Naeem,Abdelouahed Tounsi 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.2

In this research work, the analytical rotating vibration for functionally graded shell with ring supports are restricted to some volume fraction laws based on Rayleigh-Ritz technique. The frequencies of functionally grade cylindrical shells have been investigated for the distribution of material composition of material with two kinds of material. Stability of a cylindrical shell depends highly on these aspects of material with ring supports. The frequency behavior is investigated with fraction laws versus circumferential wave number, length-to-radius and height-to-radius ratios. The frequencies are higher for higher values of circumferential wave number. The frequency first increases and gain maximum value with the increase of circumferential wave mode. Moreover, the effect of angular speed is also investigated. It is examined that the backward and forward frequencies increases and decreases on increasing the ratio of height- and length-to-radius ratios.

A Study on Determining to the Appropriate Lane Width for Autonomous Vehicle

Jaehong Park,Moataz Bellah Ben Khedher,Minhyung Noh,Duk Geun Yun 한국도로학회 2022 한국도로학회 학술대회 발표논문 초록집 Vol.2022 No.10

Vibration of SWCNTs: Consistency and behavior of polynomial law index with Galerkin's model

Khadimallah, Mohamed A.,Hussain, Muzamal,Khedher, Khaled Mohamed,Bouzgarrou, Souhail Mohamed,Al Naim, Abdullah F.,Naeem, Muhammad Nawaz,Taj, Muhammad,Iqbal, Zafar,Tounsi, Abdelouahed Techno-Press 2020 Advances in nano research Vol.9 No.4

In this article, vibration attributes of single walled carbon nanotubes based on Galerkin's method have been investigated. The influence of power law index subjected to different end supports has been overtly examined. Application of the Hamilton's variational principal leads to the formation of partial differential equations. The effects of different physical and material parameters on the fundamental frequencies are investigated for armchair and zigzag carbon nanotubes with clamped-clamped, simply supported and clamped-free boundary conditions. By using volume fraction for power law index, the fundamental natural frequency spectra for two forms of Single-Walled Carbon Nanotubes (SWCNTs) are calculated. The influence of frequencies against length-to-diameter ratios with varying power law index are investigated in detail for these tubes. MATLAB software package has been utilized for extracting tube frequency spectra. The obtained results are confirmed by comparing with available literature.