Learning a measure of similarity between pairs of objects is an important generic problem in machine learning. It is particularly useful in large scale applications like searching for an image that is similar to a given image or finding videos that are relevant to a given video. In these tasks, users look for objects that are not only visually similar but also semantically related to a given object. Unfortunately, the approaches that exist today for learning such semantic similarity do not scale to large datasets. This is both because typically their CPU and storage requirements grow quadratically with the sample size, and because many methods impose complex positivity constraints on the space of learned similarity functions.The current paper presents OASIS, an Online Algorithm for Scalable Image Similarity learning that learns a bilinear similarity measure over sparse representations. OASIS is an online dual approach using the passive-aggressive family of learning algorithms with a large margin criterion and an efficient hinge loss cost. Our experiments show that OASIS is both fast and accurate at a wide range of scales: for a dataset with thousands of images, it achieves better results than existing state-of-the-art methods, while being an order of magnitude faster. For large, web scale, datasets, OASIS can be trained on more than two million images from 150K text queries within 3 days on a single CPU. On this large scale dataset, human evaluations showed that 35% of the ten nearest neighbors of a given test image, as found by OASIS, were semantically relevant to that image. This suggests that query independent similarity could be accurately learned even for large scale datasets that could not be handled before.
Introduction: Male urethral reconstruction for anterior urethral stricture has become increasingly popular and effective. Little is known about its potential impact on subsequent sexual performance. Patients and Methods: Thirty-four patients of anterior urethral stricture disease were studied from January 2008 to November 2009. The data were collected before surgery and at a follow-up of 3 months after completing the treatment. Evaluation of sexual function was done using O’Leary’s Brief Male Sexual Function Inventory. Results: Patients were divided into two categories: <40 and >40 years of age. Younger patients had more improvement in ejaculatory function and overall satisfaction after surgery than elderly. Elderly males had lower sexual drive scores. Patients with traumatic stricture had significant improvement in ejaculation and overall satisfaction. Patients without history of prior optical internal urethrotomy or dilatations reported a significant improvement in their ejaculatory function and overall satisfaction. Conclusion: Erectile dysfunction is not significant after anterior urethral reconstruction. The improvement is most pronounced in ejaculation and overall satisfaction, which was mostly appreciated by younger men. A successful urethral reconstructive procedure leads to rehabilitation of the patient back into a healthy sexual life. Dorsomedial dissection of bulbar urethra should be limited and cautery use should be minimized in that area.
PurposeTo evaluate the outcome of visual internal urethrotomy with a holmium:yttrium-aluminum-garnet laser along with intralesional triamcinolone injection.Materials and MethodsPatients with an anterior urethral stricture less than 3 cm in length were evaluated by clinical history, physical examination, uroflowmetry, and retrograde urethrogram preoperatively. All patients were treated with holmium laser urethrotomy and intralesional triamcinolone (80 mg) injection under general or regional anesthesia. An 18 F urethral catheter was placed for 5 days. All patients were followed up for 12 months postoperatively by history, uroflowmetry, and if required, retrograde urethrogram or urethroscopy every 3 months.ResultsThe mean age of the patients was 42.9 years (range, 14 to 70 years). The overall recurrence rate was 24%. The success rate in patients with strictures less than 1 cm in length was 95.8%, whereas that in patients with strictures of 1 to 3 cm in length was 57.7% (p=0.002). The outcome did not depend on age, duration of symptoms, etiology, or location of stricture.ConclusionsHolmium laser urethrotomy with intralesional triamcinolone is a safe and effective minimally invasive therapeutic modality for urethral strictures. This procedure has an encouraging success rate, especially in those with stricture segments of less than 1 cm in length.
Eosinophilic cystitis (EC) is a rare disease. It is a transmural inflammation of the bladder, predominantly with eosinophils. High index of suspicion is needed for timely intervention. EC should be kept as a differential diagnosis in patients presenting with lower urinary tract symptoms due to small capacity bladder with a negative workup for urinary tuberculosis and in patients having hematuria and negative cytology, or incidentally found bladder lesions with known risk factors. Initial treatment is conservative with removal of risk factor, anti-histaminics and steroids. Augmentation cystoplasty should be considered in patients with a small capacity bladder. These patients need a strict and long term follow-up.
This paper deals with the experimental and numerical study of closed-cell aluminum-based foam under compressive loading. Experimental samples were produced by the gas blowing method. Foam samples had an average cell size of around 1 mm, with sizes in the range 0.5–5 mm, and foam density of 0.6 g/cm3. Foam samples were subjected to a uniaxial compression test, at a displacement rate of 0.001 mm/s. Load and stress were monitored as the functions of extension and strain, respectively. For numerical modeling, CT scan images of experimental samples were used to create a volume model. Solid 3D quadratic tetrahedron mesh with TETRA 10-node elements was applied, with isotropic material behavior. A nonlinear static test with an elasto-plastic model was used in the numerical simulation, with von Mises criteria, and strain was kept below 10% by the software. Uniform compressive loading was set up over the top sample surface, in the y-axis direction only. Experimental tests showed that a 90 kN load produced complete failure of the sample, and three zones were exhibited: an elastic region, a rather uniform plateau region (around 23 MPa) and a densification region that started around 35 MPa. Yielding, or collapse stress, was achieved around 20 MPa. The densification region and a rapid rise in stress began at around 52% of sample deformation. The numerical model showed both compressive and tensile stresses within the complex stress field, indicating that shear also had a prominent role. Mainly compressive stresses were exhibited in the zones of the larger cells, whereas tensile stresses occurred in zones with an increased number of small cells and thin cell walls.
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