Inference and Learning for Generative Capsule Models

Capsule networks (see e.g. Hinton et al., 2018) aim to encode knowledge of and reason about the relationship between an object and its parts. In this paper we specify a generative model for such data, and derive a variational algorithm for inferring the transformation of each model object in a scene, and the assignments of observed parts to the objects. We derive a learning algorithm for the object models, based on variational expectation maximization (Jordan et al., 1999). We also study an alternative inference algorithm based on the RANSAC method of Fischler and Bolles (1981). We apply these inference methods to (i) data generated from multiple geometric objects like squares and triangles ("constellations"), and (ii) data from a parts-based model of faces. Recent work by Kosiorek et al. (2019) has used amortized inference via stacked capsule autoencoders (SCAEs) to tackle this problem -- our results show that we significantly outperform them where we can make comparisons (on the constellations data).Comment: 31 pages, 6 figures. This paper extends our previous work (arxiv:2103.06676) by covering the learning of the models as well as inference. Paper accepted for publication in Neural Computatio

Inference and Learning for Generative Capsule Models

Capsule networks (see e.g. Hinton et al., 2018) aim to encode knowledge of and reason about the relationship between an object and its parts. In this paper we specify a generative model for such data, and derive a variational algorithm for inferring the transformation of each model object in a scene, and the assignments of observed parts to the objects. We derive a learning algorithm for the object models, based on variational expectation maximization (Jordan et al., 1999). We also study an alternative inference algorithm based on the RANSAC method of Fischler and Bolles (1981). We apply these inference methods to (i) data generated from multiple geometric objects like squares and triangles ("constellations"), and (ii) data from a parts-based model of faces. Recent work by Kosiorek et al. (2019) has used amortized inference via stacked capsule autoencoders (SCAEs) to tackle this problem -- our results show that we significantly outperform them where we can make comparisons (on the constellations data).Comment: 31 pages, 6 figures. This paper extends our previous work (arxiv:2103.06676) by covering the learning of the models as well as inference. Paper accepted for publication in Neural Computatio

Ascites in the Puerperium in the Context of a Woman with Turner Syndrome Who Conceived through Assisted Reproductive Technology

The case is about a young female who delivered twins by caesarean section (CS). On the 4th postoperative day, she presented with ascites which was resistant to empirical antibiotic and diuretic treatment. The woman was affected by Turner syndrome (TS); she had a medical background of chronic use of hormonal medication since puberty and conceived through ART- (assisted reproduction techniques-) IVF-oocyte donation. It is important to exhibit high suspicion for clot formation in the hepatic vasculature during the puerperium, especially in the case of history of chronic hormone treatment. Ascites albumin gradient and Doppler values lead to the diagnosis of thrombosis and the administration of high doses of anticoagulants is considered to be fundamental

Extramedullary Leukemia, Presenting at the Cervix of the Uterus

Extramedullary relapse of leukemia is encountered more often than in the past. The reason is that leukemia survival rates increase with improved treatment schemes. We present a rare case of involvement of the cervix of the uterus in an adult B Acute Lymphocytic Leukemia (B-ALL) survivor. Relapses affect various organs but rarely the female genital tract. Nevertheless, in this case, a woman with a history of induced amenorrhea due to treatment for leukemia presented to the gynecologist because of vaginal spotting. Colposcopy evaluation of the vagina/cervix, sonography and cytological and histological sampling established the diagnosis of leukemia relapse in the cervix of the uterus. Under these circumstances, our study highlights the rare extramedullary presentation of leukemia in the cervix of the uterus of a young lady considered to be disease-free and listed for bone marrow transplantation. In this rare case of relapse in the cervix of the uterus, Pap smears alarmed physicians, and radiology examinations assisted the diagnostic workup. Still, only biopsy, microscopic evaluation, and immunohistochemistry studies established the exact diagnosis. Prognosis in the situation of extramedullary disease relapse in the female genital tract was poor, but gynecologists’ high suspicion led to a prompt diagnosis. Survival is in general limited, but together with high suspicion, multidisciplinary team involvement is imperative to improve the reduced chances of survival