RESUMO
In this paper we describe a novel method for determining synergies between joint motions in reaching movements by hierarchical clustering. A set of recorded elbow and shoulder trajectories is used in a learning algorithm to determine the relationships between angular velocities at elbow and shoulder joints. The learning algorithm is based on optimal criteria for obtaining the hierarchy of descriptions of movement trajectories. We show that this method finds complex synergism between optimal joint trajectories for a given set of data and angular velocities at the shoulder and elbow joints. Three other machine learning techniques (ML) are used for comparison with our method of hierarchical clustering of trajectories. These MLs are: (1) radial basis functions (RBF), (2) inductive learning (IL), and (3) adaptive-network-based fuzzy inference system (ANFIS). Better error characteristics were obtained using the method of hierarchical clustering in comparison with the other techniques. The advantage of the method of hierarchical clustering with respect to the other MLs is in integrating the spatial and temporal elements of reaching movements. Determination and analysis of spatio-temporal events of movement trajectories is a useful tool in designing control systems for functional electrical stimulation (FES) assisted manipulation.
Assuntos
Inteligência Artificial , Articulação do Cotovelo/fisiologia , Movimento , Articulação do Ombro/fisiologia , Algoritmos , Análise por Conglomerados , Lógica Fuzzy , Humanos , Redes Neurais de ComputaçãoRESUMO
Gastrointestinal stromal tumors (GIST) are rare mesenchimal neoplasmas of the gastrointestinal tract. The diagnosis of this tumors are oftenly very difficult. Patients with this tumor are ussualy addmited to the hospital cause of the gastrointestinal bleeding, abdominal pain, abdominal distension, disphagia, obstructive jaundice and bowel obsstruction. In this case report, we present a 86 year old patient with massive GIST of the stomach which was not preoperatively diagnosed.
Assuntos
Tumores do Estroma Gastrointestinal/patologia , Neoplasias Gástricas/patologia , Idoso de 80 Anos ou mais , Feminino , HumanosRESUMO
Benign multicystic mesothelioma (MCM) of the peritoneum is a rare lesion that occurs predominantly in middle aged women with previous history of pelvic surgery. We report a case of MCM of the peritoneum in a 25-year-old man in whom cystic masses were twice surgically removed in an interval of 1.5 year. Ultrasonography and computer assisted tomography of the abdomen revealed a multicystic abdominal and pelvic mass. At first laparotomy, a multiple, thin-walled cysts ranging 0.5-7 cm in diameter were found involving the abdominal and pelvic peritoneum. After removal of all visible cysts we made histopathological diagnosis of the multilocular cavernous lymphangioma, without immunohistochemical examinations. The recurrent tumor was clinically and pathologically identical, but the final diagnosis, established upon immunohistochemical staining, was MCM: the tumor cells were strongly positive for cytokeratin, weakly positive for vimentin, and negative for Factor VIII. Management of the MCM surgical excision, unfortunately not always curative, since there is a high recurrence rate.