5 results on '"G Sahar"'
Search Results
2. Planning of Minimum- Time Trajectories for Robot Arms
- Author
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G. Sahar and John M. Hollerbach
- Subjects
0209 industrial biotechnology ,Engineering ,Mathematical optimization ,02 engineering and technology ,Workspace ,law.invention ,Computer Science::Robotics ,Industrial robot ,020901 industrial engineering & automation ,Artificial Intelligence ,Displacement control ,law ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,business.industry ,Applied Mathematics ,Mechanical Engineering ,Minimum time ,Control engineering ,Modeling and Simulation ,Robot ,Graph (abstract data type) ,020201 artificial intelligence & image processing ,business ,Actuator ,Robotic arm ,Software - Abstract
The minimum-time path for a robot arm has been a long standing and unsolved problem of considerable interest. We present a general solution to this problem which involves joint-space tessellation, a dynamic time-scaling algorithm, and a graph search. The solution incorporates full dynamics of movement and actuator constraints, and can easily be extended for joint limits and workspace obstacles. It was found that optimal paths tend to be nearly straight lines in joint space. We discuss implementation difficulties due to the tessellation and to combinatorial proliferation of paths.
- Published
- 1986
- Full Text
- View/download PDF
3. Wrist-Partitioned, Inverse Kinematic Accelerations and Manipulator Dynamics
- Author
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G. Sahar and John M. Hollerbach
- Subjects
Kinematic chain ,Engineering ,0209 industrial biotechnology ,321 kinematic structure ,Inertial frame of reference ,Computation ,Inverse ,02 engineering and technology ,Kinematics ,Inverse dynamics ,Computer Science::Robotics ,Acceleration ,020901 industrial engineering & automation ,Artificial Intelligence ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Astrophysics::Galaxy Astrophysics ,Mathematics ,Inverse kinematics ,business.industry ,Applied Mathematics ,Mechanical Engineering ,Motion control ,Modeling and Simulation ,020201 artificial intelligence & image processing ,business ,Software - Abstract
An efficient algorithm is presented for the calculation of the inverse kinematic accelerations for a six-degree-of-freedom manipulator with a spherical wrist. The inverse kinematic calculation is shown to work synergistically with the inverse dynamic calculation, producing kinematic parameters needed in the recursive Newton-Euler dynamics formulation. Additional savings in the dynamic computation are noted for a class of kinematically well-structured manipulators, such as spherical-wrist arms, and for manipulators with simply structured inertial parameters.
- Published
- 1983
- Full Text
- View/download PDF
4. The Role of Ambulatory Surgery of Thrombosed Varicose Veins
- Author
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Raphael Reiss, M Haddad, Zelikovski A, and G. Sahar
- Subjects
medicine.medical_specialty ,Varix ,business.industry ,General Medicine ,030204 cardiovascular system & hematology ,medicine.disease ,Thrombosis ,Surgery ,03 medical and health sciences ,Regimen ,0302 clinical medicine ,Pharmacotherapy ,Varicose veins ,Ambulatory ,medicine ,030212 general & internal medicine ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business - Abstract
Superificial thrombosis is among the most frequent complications of varicose veins. Miscellaneous treatments have been attempted for relief of patients' symptoms, most of them unsatisfactory. We advocate simple evacuation of the thrombosed varix followed by elastic bandaging and walking exercises, a regimen which gives relief in a short period. Treatment of varicose veins should follow; no drug therapy is necessary.
- Published
- 1986
- Full Text
- View/download PDF
5. Concomitant grafting of both postbifurcation internal thoracic artery branches.
- Author
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Sahar G, Wolak A, Matsa M, Shelef I, Raichel L, Ishay Y, and Lev-Ran O
- Subjects
- Aged, Coronary Angiography methods, Female, Follow-Up Studies, Humans, Male, Mammary Arteries diagnostic imaging, Middle Aged, Multidetector Computed Tomography methods, Postoperative Period, Treatment Outcome, Internal Mammary-Coronary Artery Anastomosis methods, Mammary Arteries surgery, Vascular Patency
- Abstract
Objective: We aimed to assess the clinical outcome and graft patency after concomitant grafting of both postbifurcation internal thoracic artery (ITA) branches., Methods: Between 2007 and 2013, 17 patients (14 men; mean [SD] age, 60 [9.3] years) underwent skeletonized bifurcated ITA grafting. Respective targets were restricted to non-left anterior descending (LAD) area. In all patients, a complementary standard ITA was used to graft the LAD artery. Graft patency was assessed by standard coronary angiography or serial multidetector computed tomography., Results: Of the bifurcated conduits, 94% were right ITA. Respective right ITA target sets were first and second obtuse marginal arteries (M1-M2) (n = 12), ramus-M1 (n = 2), and distal right coronary artery-posterior descending artery (n = 2). Right ITAs were mobilized retroaortic (via the transverse sinus) in 14 patients (82%) (to circumflex artery targets). Circumflex artery targets comprised 88.2% of all anastomoses (30/34). There were no early mortalities, myocardial infarctions, or hypoperfusion syndromes. During median follow-up of 44 months (range, 3-63), there was no late mortality. Overall reintervention rate was 11.7%, and bifurcated ITA-related reintervention rate was 5.8%. At 5 years, freedom from major adverse cardiac or cerebrovascular event related to bifurcated ITA respective territory was 87% (Kaplan-Meier). Coronary imaging was achieved in 76% of the patients (elective multidetector computed tomography, n = 9; symptoms-directed coronary catheterization, n = 4). Bifurcation branch patency rate was 88.4% (23/26) at a median of 3.5 years., Conclusions: Grafting both postbifurcation ITA branches is technically feasible and may be selectively considered. Current observations are valid for skeletonized conduits and limited to non-LAD targets. These preliminary findings should be corroborated by larger data sets.
- Published
- 2015
- Full Text
- View/download PDF
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