Robust DERIVATIVE Operator into Gradient Based SIGNAL Processing

Hadi Sadoghi Yazdi,Hadi Dehdast 보안공학연구지원센터 2012 International Journal of Control and Automation Vol.5 No.4

Least mean square algorithm tuned by fuzzy c-means for impulsive noise suppression of gray-level images

Mahdipour Hossein-Abad Hadi,Khademi Morteza,Sadoghi Yazdi Hadi 보안공학연구지원센터(IJSIP) 2010 International Journal of Signal Processing, Image Vol.3 No.4

Large amplitude free vibrations of FGM shallow curved tubes in thermal environment

Hadi Babaei,Yaser Kiani,M. Reza Eslami 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.6

In the current investigation, large amplitude free vibration behavior of shallow curved pipes (tubes) made of functionally graded materials is investigated. Properties of the tube are distributed across the radius of the tube and are obtained by means of a power law function. It is also assumed that all thermo-mechanical properties are temperature dependent. The governing equations of the tube are obtained using a higher order shear deformation tube theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the tube. The von Kármán type of geometrical non-linearity is included into the formulation to consider the large displacements and small strains. Uniform temperature elevation of the tube is also included into the formulation. For the case of tubes which are simply supported in flexure and axially immovable, the governing equations are solved using the two-step perturbation technique. Closed form expressions are provided to obtain the small and large amplitude fundamental natural frequencies of the FGM shallow curved tubes in thermal environment. Numerical results are given to explore the effects of thermal environment, radius ratio, and length to thickness ratio of the tube on the fundamental linear and non-linear frequencies.

Utility of FDG-PET/CT for the Detection and Characterization of Sternal Wound Infection Following Sternotomy

Hadi Hariri,Stéphanie Tan,Patrick Martineau,Yoan Lamarche,Michel Carrier,Vincent Finnerty,Sébastien Authier,Francois Harel,Matthieu Pelletier-Galarneau 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.4

Purpose FDG-PET/CT has the potential to play an important role in the diagnosis of sternal wound infections (SWI). The purpose of this study was to analyze the diagnostic accuracy of FDG-PET/CT for SWI in patients following sternotomy. Methods We performed a single-center, retrospective analysis of patients who had undergone median sternotomy and FDG-PET/ CT imaging. The gold standard consisted of positive bacterial culture and/or the presence of purulent material at surgery. Qualitative patterns of sternal FDG uptake, SUVmax, and associated CT findings were determined, and an imaging scoring system was developed. The diagnostic performances were studied in both the recent (≤ 6 months between sternotomy and imaging) and remote surgery phase (> 6 months). Results A total of 40 subjects were identified with 11 confirmed SWI cases. Consensus interpretation was associated with a sensitivity of 91%and specificity of 97%. Combination of uptake patterns yielded an AUC of 0.96 while use of SUVmax yielded an AUC of 0.82. Conclusions Results suggest that FDG-PET/CT may be useful for the diagnosis of SWI with optimal diagnostic accuracy achieved by identifying specific patterns of uptake. SUVmax can be helpful in assessing subjects with remote surgery, but its use is limited in the context of recent surgery. Further studies are required to confirm these results.

Optimization of a subsonic wind tunnel nozzle with low contraction ratio via ball-spine inverse design method

Hadi Hoghooghi,Mahdi Nili-Ahmadabadi,Mojtaba Dehghan Manshadi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

The goal of wind tunnel design is to generate a uniform air flow with minimum turbulence intensity and low flow angle. The nozzle is the main component of wind tunnels to create a uniform flow with minimal turbulence. Pressure distribution along nozzle walls directly affects the boundary layer thickness, pressure losses and non-uniformity of flow velocity through the test section. Although reduction of flow turbulences and non-uniformity through the test section can be carried out by nozzles with high contraction ratio, it increases the construction cost of the wind tunnel. For decreasing the construction cost of nozzle with constant test section size and mass flow rate, the contraction ratio and length of nozzle should be decreased; that causes the non-uniformity of outlet velocity to increase. In this study, first, three types of nozzle are numerically investigated to compare their performance. Then, Sargison nozzle with contraction ratio of 12.25 and length of 7 m is scaled down to decrease its weight and construction cost. Having scaled and changed to a nozzle with contraction ratio of 9 and length of 5 m, its numerical solution reveals that the non-uniformity of outlet velocity increases by 21%. By using the Ballspine inverse design method, the pressure distribution of the original Sargison nozzle is first scaled and set as the target pressure of the scaled down nozzle and geometry correction is done. Having reached the target nozzle, numerical solution of flow inside the optimized nozzle shows that the non-uniformity just increases by 5% in comparison with the original Sargison nozzle.

Diagnosis of Fungal Infection (Candida albicans) After Heart Transplantation in a Pediatric Case with Fever of Unknown Origin: Role of 99mTc‑UBI SPECT/CT and 18F‑FDG PET/CT

Hadi Malek,Raheleh Hedayati,Mahdi Maghsudi,Nahid Yaghoobi 대한핵의학회 2023 핵의학 분자영상 Vol.57 No.3

The diagnosis of patients with fever of unknown origin (FUO) in pediatric heart transplantation is a challenging medicalproblem. The physician should differentiate between rejections, infections, malignancy, adrenal insufficiency, and drugfever. Immunosuppressive therapy in these patients exposes them to a high risk of developing a post-transplantation fungalinfection. In this case, we discuss the diagnostic contribution of the 99mTc-UBI scan and 18F-FDG PET scan for diagnosisof fungal infection causing FUO in these patients.

Groundwater Inflow Assessment to Karaj Water Conveyance Tunnel, Northern Iran

Hadi Farhadian,Arash Nikvar Hassani,Homayoon Katibeh 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.6

In this paper, groundwater inflow into Karaj Water Conveyance (KWC) tunnel was estimated using analytical and numerical methods in 12 different sections of the tunnel length. Further, these sections were rated from groundwater hazard point of view by means of Site Groundwater Rating (SGR) factor. Comparing results show a reasonable accordance between observed water ingress rate and those various methods. Since, KWC tunnel is excavated in fractured rocks with a high level of anisotropy, analytical methods provided highly overestimated water inflow rate. Furthermore all SGR, analytical and numerical results, show high levels of water inflow from fault zones. Maximum water inflow into tunnel was computed as 0.0536 and 0.0432 lit/sec/m using analytical and numerical methods, respectively. Based on SGR method, 11 out of 12 sections in KWC tunnel length are found to be in “No Risk” class with groundwater inflow of less than 0.04 lit/sec/m which are in agreement with analytical and numerical seepage values and also with the observed inflow rate.

On the proximal point method for an infinite family of equilibrium problems in Banach spaces

Hadi Khatibzadeh 대한수학회 2019 대한수학회보 Vol.56 No.3

In this paper, we study the convergence analysis of the sequences generated by the proximal point method for an infinite family of pseudo-monotone equilibrium problems in Banach spaces. We first prove the weak convergence of the generated sequence to a common solution of the infinite family of equilibrium problems with summable errors. Then, we show the strong convergence of the generated sequence to a common equilibrium point by some various additional assumptions. We also consider two variants for which we establish the strong convergence without any additional assumption. For both of them, each iteration consists of a proximal step followed by a computationally inexpensive step which ensures the strong convergence of the generated sequence. Also, for this two variants we are able to characterize the strong limit of the sequence: for the first variant it is the solution lying closest to an arbitrarily selected point, and for the second one it is the solution of the problem which lies closest to the initial iterate. Finally, we give a concrete example where the main results can be applied.

Investigation of the model scale and particle size effects on the point load index and tensile strength of concrete using particle flow code

Hadi Haeri,Vahab Sarfarazi,Zheming Zhu,Ahmadreza Hedayat,Mohammad Fatehi Marji 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.4

In this paper the effects of particle size and model scale of concrete have been investigated on point load index, tensile strength, and the failure processes using a PFC2D numerical modeling study. Circular and semi-circular specimens of concrete were numerically modeled using the same particle size, 0.27 mm, but with different model diameters of 75 mm, 54 mm, 25 mm, and 12.5 mm. In addition, circular and semi-circular models with the diameter of 27 mm and particle sizes of 0.27 mm, 0.47 mm, 0.67 mm, 0.87 mm, 1.07 mm, and 1.27 mm were simulated to determine whether they can match the experimental observations from point load and Brazilian tests. The numerical modeling results show that the failure patterns are influenced by the model scale and particle size, as expected. Both Is(50) and Brazilian tensile strength values increased as the model diameter and particle sizes increased. The ratio of Brazilian tensile strength to Is(50) showed a reduction as the particle size increased but did not change with the increase in the model scale.

A new insight into design of acoustic liner arrays arrangement in the presence of a grazing flow

Hadi Dastourani,Iman Bahman-Jahromi Techno-Press 2023 Advances in computational design Vol.8 No.4

This study evaluated the acoustic performance of two configurations of serial HR arrays and lined HR arrays in the presence of grazing flow using a 3D numerical simulation. The dual, triple, and quad HR arrays were compared to the conventional HR array. The simulation results showed that the number of resonant frequencies increased with the number of serial HR arrays. The C_TL did not significantly change with the number of serial HR arrays. The acoustic performance of the two, three, and four-lined HR arrays was compared to the conventional HR array. The results showed that the resonant frequency and TLmax increased with the number of lined HR arrays. The C_TL also increased with the number of lined HR arrays. The effect of the grazing flow Mach number (M_a) was investigated on the four-lined HR array configuration and compared to the conventional HR configuration. TLmax and C_TL decreased for both configurations with increasing M_a. The four-lined HR array configuration had significantly better acoustic performance than the conventional HR configuration. The TLmax and C_TL increased by more than 300% when the configuration was changed from the conventional HR to the four-lined HR array at M_a = 0.The increment percentage decreased with increasing M_a.