Radiolucent rim as a possible diagnostic aid for differentiating jaw lesions

Hamed Mortazavi,Maryam Baharvand,Somayeh Rahmani,Soudeh Jafari,Parvin Parvaei 대한영상치의학회 2015 Imaging Science in Dentistry Vol.45 No.4

In this study, we formulate a new proposal that complements previous classifications in order to assist dental practitioners in performing a differential diagnosis based on patients’ radiographs. We used general search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks to find relevant studies by using keywords such as “jaw disease,” “jaw lesions,” “radiolucent rim,” “radiolucent border,” and “radiolucent halo.” More than 200 articles were found, of which 70 were broadly relevant to the topic. We ultimately included 50 articles that were closely related to the topic of interest. When the relevant data were compiled, the following eight lesions were identified as having a radiolucent rim: periapical cemento-osseous dysplasia, focal cemento-osseous dysplasia, florid cemento-osseous dysplasia, cemento-ossifying fibroma, osteoid osteoma, osteoblastoma, odontoma, and cementoblastoma. We propose a novel subcategory, jaw lesions with a radiolucent rim, which includes eight entities. The implementation of this new category can help improve the diagnoses that dental practitioners make based on patients’ radiographs.

Investigation of a nonlinear dynamic hydraulic system model through the energy analysis approach†

Hamed Hossein Afshari,Mostafa Ehramianpour,Morteza Mohammadi 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.11

The dynamics of a pressure regulator valve have been studied using the through Bondgraph simulation technique. This valve consists of several elements that can transmit, transform, store, and consume hydraulic energy. The governing equations of the system have been derived from the dynamic model. In solving system equations numerically, various pressure-flow characteristics across the regulator ports and orifices have been taken into consideration. This simulation study identifies some critical parameters that have significant effects on the transient response of the system. The results have been obtained using the MATLAB-SIMULINK environment. The main advantage of the proposed methodology is its ability to model the nonlinear behavior of the hydraulic resistance of system elements as a function of the fluid flow rate.

An analytical guidance law of planetary landing mission by minimizing the control effort expenditure

Hamed Hossein Afshari,Alireza Basohbat Novinzadeh,Jafar Roshanian 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.12

An optimal trajectory design of a module for the planetary landing problem is achieved by minimizing the control effort expenditure. Using the calculus of variations theorem, the control variable is expressed as a function of costate variables, and the problem is converted into a two-point boundary-value problem. To solve this problem, the performance measure is approximated by employing a trigonometric series and subsequently, the optimal control and state trajectories are determined. To validate the accuracy of the proposed solution, a numerical method of the steepest descent is utilized. The main objective of this paper is to present a novel analytic guidance law of the planetary landing mission by optimizing the control effort expenditure. Finally, an example of a lunar landing mission is demonstrated to examine the results of this solution in practical situations.

CFD-based Design and Analysis of the Ventilation of an Electric Generator Model, Validated with Experiments

Hamed Jamshidi,Håkan Nilsson,Valery Chernoray 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.2

The efficiency of the ventilation system is a key point for durable and reliable electric generators. The design of such system requires a detailed understanding of the air flow in the generator. Computational fluid dynamics (CFD) has the potential to resolve the lack of information in this field. The present work analyses the air flow inside a generator model. The model is designed using a CFD-based approach, and manufactured by taking into consideration the experimental and numerical requirements and limitations. The emphasis is on the possibility to accurately predict and experimentally measure the flow distribution inside the stator channels. A major part of the work is focused on the design of an intake and a fan that gives an evenly distributed flow with a high flow rate. The intake also serves as an accurate flowmeter. Experimental results are presented, of the total volume flow rate, the total pressure and velocity distributions. Steady-state CFD simulations are performed using the FOAM-extend CFD toolbox. The simulations are based on the multiple rotating reference frames method. The results from the frozen rotor and mixing plane rotor-stator coupling approaches are compared. It is shown that the fan design provides a sufficient flow rate for the stator channels, which is not the case without the fan or with a previous fan design. The detailed experimental and numerical results show an excellent agreement, proving that the results reliable.

A Unified Trust Model for Pervasive Environments - Simulation and Analysis

( Hamed Khiabani ),( Norbik Bashah Idris ),( Jamalul-lail Ab Manan ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.7

Ubiquitous interaction in a pervasive environment is the main attribute of smart spaces. Pervasive systems are weaving themselves in our daily life, making it possible to collect user information invisibly, trust model which unifies different trust factors like context, recommendation, and history to calculate the trust level of each in an unobtrusive manner by known and even unknown parties. Huge number of interactions between users and pervasive devices necessitate a comprehensive party precisely. Trusted computing enables effective solutions to verify the trustworthiness of computing platforms. In this paper, we elaborate Unified Trust Model (UTM) which calculates entity`s trustworthiness based on history, recommendation, context and platform integrity measurement, and formally use these factors in trustworthiness calculation. We evaluate UTM behaviour by simulating in different scenario experiments using a Trust and Reputation Models Simulator for Wireless Sensor Networks. We show that UTM offers responsive behaviour and can be used effectively in the low interaction environments.

Pulmonary Tuberculosis Diagnosis: Where We Are?

( Hamed Ebrahimzadeh Leylabadlo ),( Hossein Samadi Kafil ),( Mehdi Yousefi ),( Mohammad Aghazadeh ),( Mohammad Asgharzadeh ) 대한결핵 및 호흡기학회 2016 Tuberculosis and Respiratory Diseases Vol.79 No.3

In recent years, in spite of medical advancement, tuberculosis (TB) remains a worldwide health problem. Although many laboratory methods have been developed to expedite the diagnosis of TB, delays in diagnosis remain a major problem in the clinical practice. Because of the slow growth rate of the causative agent Mycobacterium tuberculosis , isolation, identification, and drug susceptibility testing of this organism and other clinically important mycobacteria can take several weeks or longer. During the past several years, many methods have been developed for direct detection, species identification, and drug susceptibility testing of TB. A good understanding of the effectiveness and practical limitations of these methods is important to improve diagnosis. This review summarizes the currently-used advances in nonmolecular and molecular diagnostics.

Numerical Modeling of Charge Transport in Polymer Materials Under DC Continuous Electrical Stress

Hamed, Boukhari,Fatiha, Rogti The Korean Institute of Electrical and Electronic 2015 Transactions on Electrical and Electronic Material Vol.16 No.3

Our work is based on the development of a numerical model to develop a methodology for predicting the aging and breakdown in insulation due to the dynamics of space charge packets. The model of bipolar charge transports is proposed to simulate space charge dynamic for high DC voltage in law-density polyethylene (LDPE), taking into account the trapping and detrapping of recombination phenomena, this model has been developed and experimentally validation. Theoretical formulation of the physical problem is based on the Poisson, the continuity and the transport equations as well as on the appropriate models for injection. Numerical results provide temporal and local distributions of the electric field, the space charge density for the different kinds of charges, conduction and displacement current densities, and the external current.

A mathematical steel panel zone model for flanged cruciform columns

Hamed Saffari,Sina Sarfarazi,Ali Fakhraddini 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.4

Cruciform sections are an appropriate option for columns of orthogonal moment resisting frames for equal bending strength and stiffness about two main axes and the implementation is easier for continuity plates. These columns consist of two I-shaped sections, so that one of them is cut out in middle and two generated T-shaped sections be welded into I-shaped profile. Furthermore, in steel moment frames, unbalance moment at the beamcolumn connection leads to shear deformation in panel zone. Most of the obtained relations for panel zone strength derived from experimental and analytical results are on I-shaped columns with almost thin flanges. In this paper, a parametric study has been carried out using Finite Element Method (FEM) with effective parameters at the panel zone behavior. These parameters consist of column flange thickness, column web thickness, and thickness of continuity plates. Additionally, a mathematical model has been suggested to determine strength of cruciform column panel zone and has been shown its accuracy and efficiency.

Suggesting double-web I-shaped columns for omitting continuity plates in a box-shaped column

Hamed Saffari,Amir A. Hedayat,Nasrin Soltani Goharrizi 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.6

Generally the required strength and stiffness of an I-shaped beam to the box-shaped columnconnection is achieved if continuity plates are welded to the column flanges from all sides. However,welding the forth edge of a continuity plate to the column flange may not be easily done and is normallyaccompanied by remarkable difficulties. This study was aimed to propose an alternative for box columnswith continuity plates to diminish such problems. For this purpose a double-web I-shaped column wasproposed. In this case the strength and rotational stiffness of the connection was provided by nearing thecolumn webs to each other. Finite element studies on about 120 beam-column connections showed that theoptimum proportion of the distance between two column webs and the width of the column flange(parameter β) was a function of the ratio of the beam flange width to the column flange width (parameter α). Hence, based on the finite element results, an equation was proposed to estimate the optimum value ofparameter β in terms of parameter α to achieve the highest connection performance. Results also showed thatthe strength and ductility of post-Northridge connections of such columns are in average 12.5 % and 54%respectively higher than those of box-shaped columns with ordinary continuity plates. Therefore, adouble-web I-shaped column of optimum arrangement might be a proper replacement for a box column withcontinuity plates when beams are rigidly attached to it.

Fuzzy Logic Self-tuning PID Controller Design Based on Smith Predictor for Heating System

Hamed Khodadadi,Ali Dehghani 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

The heating, ventilation, and air conditioning is a technology used in smart buildings, providing thermal comfort and acceptable air quality. Heating system is the most important part of this technology and several methods have been proposed for controlling it. The model of heating system includes time delay. Moreover, the model parameters are changed based on the operation mode. In this paper, Smith predictor is proposed as a solution for controlling the time delayed system. In addition, to overcome the uncertain condition of the model, a self-tuning PID controller is employed based on the fuzzy logic. Therefore, in this paper, a self-tuning fuzzy logic PID controller based on Smith predictor is proposed to control the heating system. The findings obtained from various simulation results verified the remarkable precision of the proposed method in controlling the heating system in comparison to the other controllers like PID and PID based on Smith predictor.