Unsupervised Segmentation of Images Based on Shuffled Frog-Leaping Algorithm

Tehami, Amel,Fizazi, Hadria Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.2

The image segmentation is the most important operation in an image processing system. It is located at the joint between the processing and analysis of the images. Unsupervised segmentation aims to automatically separate the image into natural clusters. However, because of its complexity several methods have been proposed, specifically methods of optimization. In our work we are interested to the technique SFLA (Shuffled Frog-Leaping Algorithm). It's a memetic meta-heuristic algorithm that is based on frog populations in nature searching for food. This paper proposes a new approach of unsupervised image segmentation based on SFLA method. It is implemented and applied to different types of images. To validate the performances of our approach, we performed experiments which were compared to the method of K-means.

Unsupervised Segmentation of Images Based on Shuffled Frog-Leaping Algorithm

( Amel Tehami ),( Hadria Fizazi ) 한국정보처리학회 2017 Journal of information processing systems Vol.13 No.2

The image segmentation is the most important operation in an image processing system. It is located at the joint between the processing and analysis of the images. Unsupervised segmentation aims to automatically separate the image into natural clusters. However, because of its complexity several methods have been proposed, specifically methods of optimization. In our work we are interested to the technique SFLA (Shuffled Frog-Leaping Algorithm). It`s a memetic meta-heuristic algorithm that is based on frog populations in nature searching for food. This paper proposes a new approach of unsupervised image segmentation based on SFLA method. It is implemented and applied to different types of images. To validate the performances of our approach, we performed experiments which were compared to the method of K-means.

Creep Effect on Composite Beam with Perfect Steel-concrete Connection

Abdelaziz Souici,Mohamed Tehami,Nacer Rahal,M. S. Bekkouche,J. F. Berthet 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.2

In the context of primary creep, a new approach to the study of the effects of creep on the resistance of a composite beam is reported. The beam is in perfect connection, statically determinate and bent under a moderate load applied at time t0. The proposed model is based primarily on the theory of linear viscoelasticity of concretes and specifically on the principle of the irreversible law of deformation established by Dischinger. In this work, two equations of equilibrium and two other equations of compatibility at the steel-concrete interface are considered. This compatibility is rewritten according to Dischinger’s rheological equation for ageing materials while adopting elastic behaviour for the metal profile. Then, the mathematical treatment of the written compatibility should lead to the establishment of a system of two differential equations of the first order. The analytical resolution of this system provides the expressions for the generalized internal forces of the composite beam in terms of time. Using these mathematical expressions, it is easy to predict the state of internal stresses and the strains of the beam at any time, t. Finally, the proposed analytical approach is confronted with various other methods.

Effects of Partial Shear Connection on the Behavior of Semi-continuous Composite Beams

Messaoud Titoum,Mohamed Tehami,Belkacem Achour 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.4

In this paper, the effects of partial shear connection on the behavior of semi-continuous composite beams were studied numerically using two-dimensional finite element model with plane stress elements. The finite element model takes into account the nonlinearity of the different materials involved. For the shear connectors, a non-linear (shear-slip) relation, drawn from the push-out tests, was used. The accuracy of the proposed finite element model was verified against test results available in the literature. A simplified method to predict load capacity and deflection of the semi-continuous composite beams was also proposed. Based on the results obtained from the finite element analysis, the concept of partial shear connection in the hogging moment regions can be accepted provided that the shear connectors are sufficiently ductile. In this paper, the effects of partial shear connection on the behavior of semi-continuous composite beams were studied numerically using two-dimensional finite element model with plane stress elements. The finite element model takes into account the nonlinearity of the different materials involved. For the shear connectors, a non-linear (shear-slip) relation, drawn from the push-out tests, was used. The accuracy of the proposed finite element model was verified against test results available in the literature. A simplified method to predict load capacity and deflection of the semi-continuous composite beams was also proposed. Based on the results obtained from the finite element analysis, the concept of partial shear connection in the hogging moment regions can be accepted provided that the shear connectors are sufficiently ductile.

Increased ERCP volume improves cholangiogram interpretation: a new performance measure for ERCP training?

Shyam Vedantam,Sunil Amin,Ben Maher,Saqib Ahmad,Shanil Kadir,Saad Khalid Niaz,Mark Wright,Nadeem Tehami 대한소화기내시경학회 2022 Clinical Endoscopy Vol.55 No.3

Background/Aims: Cholangiogram interpretation is not used as a key performance indicator (KPI) of endoscopic retrograde cholangiopancreatography(ERCP) training, and national societies recommend different minimum numbers per annum to maintain competence. This study aimed to determine the relationship between correct ERCP cholangiogram interpretation and experience. Methods: One hundred fifty ERCPists were surveyed to appropriately interpret ERCP cholangiographic findings. There were threegroups of 50 participants each: “Trainees,” “Consultants group 1” (performed >75 ERCPs per year), and “Consultants group 2” (performed>100 ERCPs per year). Results: Trainees was inferior to Consultants groups 1 and 2 in identifying all findings except choledocholithiasis outside the intrahepaticduct on the initial or completion/occlusion cholangiogram. Consultants group 1 was inferior to Consultants group 2 in identifyingStrasberg type A bile leaks (odds ratio [OR], 0.86; 95% confidence interval [CI], 0.77−0.96), Strasberg type B (OR, 0.84; 95% CI,0.74−0.95), and Bismuth type 2 hilar strictures (OR, 0.81; 95% CI, 0.69−0.95). Conclusions: This investigation supports the notion that cholangiogram interpretation improves with increased annual ERCP casevolumes. Thus, a higher annual volume of procedures performed may improve the ability to correctly interpret particularly difficultfindings. Cholangiogram interpretation, in addition to bile duct cannulation, could be considered as another KPI of ERCP training.

Initial United Kingdom experience of endoscopic ultrasound-directed transgastric endoscopic retrograde cholangiopancreatography

Puneet Chhabra,Wei On,Bharat Paranandi,Matthew T. Huggett,Naomi Robson,Mark Wright,Ben Maher,Nadeem Tehami 한국간담췌외과학회 2022 Annals of hepato-biliary-pancreatic surgery Vol.26 No.4

Management of infected post-pancreatic resection fluid collections under endoscopic ultrasound guidance using lumen apposing metal stent: A case series and review of the literature

Puneet Chhabra,Ben Maher,Dharmadev Trivedi,Dimitrios Karavias,Ali Arshad,Mark Wright,Nadeem Tehami 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.4

Backgrounds/Aims: Post-operative pancreatic fistulas (POPF) and fluid collections (POPFC) remain significant sources of morbidity and mortality after pancreatic resections. There remains a paucity of literature describing endoscopic ultrasound (EUS) guided drainage of POPFC using a Hot AXIOS<SUP>TM</SUP> lumen apposing metal stent (LAMS). Methods: We conducted a retrospective study, encompassing all consecutive patients with POPFC managed using Hot AXIOS<SUP>TM</SUP> LAMS at our institution between January 2017 and December 2019. Primary outcome measures were technical and clinical success. Secondary outcome measures were adverse events and recurrence rates. Results: Five patients underwent EUS guided drainage using Hot AXIOSTM LAMS during the study period. Mean age of patients was 67.8 ± 2.16 years. The majority (60.0%) of patients were males. Median duration of symptom onset after surgery was 9 days. All patients presented with abdominal pain. Median size of the collection measured on computed tomography was 91 mm. Median interval time between symptom onset and EUS drainage was 30 days. Two patients required percutaneous drainage prior to EUS guided drainage. Technical and clinical success were achieved for all patients. No adverse events were observed. Median duration of follow-up was 90 days. No recurrence of collection occurred during the follow-up period. Conclusions: EUS guided drainage of POPFC using Hot AXIOS<SUP>TM</SUP> LAMS is a safe and effective treatment modality with technical and clinical success rates of 100% in our experience.