AUCS/TR9502 Combining Schema Theory with Fuzzy-Logic to Control a Mobile Robot

A mobile robot operating in a real world environment requires the ability to cope with uncertain, incomplete, and approximate information in real time. In this paper, a new architecture for controlling a mobile robot which takes abstracts goals into consideration is described. Schema theory is used to specify the primitive behaviours of the robot and these behaviours are combined by a fuzzy-logic controller . Simulation results are presented which demonstrate the feasibility of the approach. 1 Introduction There are many approaches to the control of mobile robots which interact with a dynamic, uncertain environment. Brooks [4] discusses the problems of applying traditional AI techniques to mobile robot control and instead proposes a physically-grounded, reactive subsumption architecture for the intelligent control of mobile robots. This view is challenged in [5], where the authors state that although a Brooksian behaviour generation approach can go a long way towards modelling intel..

Combining Schema Theory with Fuzzy-Logic to Control a Mobile Robot

. A mobile robot operating in a real world environment requires the ability to cope with uncertain, incomplete, and approximate information in real time. In this paper, a new architecture for controlling a mobile robot which takes abstracts goals into consideration is described. Schema theory is used to specify the primitive behaviours of the robot and these behaviours are combined by a fuzzy-logic controller . Simulation results are presented which demonstrate the feasibility of the approach. Key Words. Mobile robots, fuzzy-logic control, schema theory INTRODUCTION There are many approaches to the control of mobile robots which interact with a dynamic, uncertain environment. Brooks [4] discusses the problems of applying traditional AI techniques to mobile robot control and instead proposes a physically-grounded, reactive subsumption architecture for the intelligent control of mobile robots. This view is challenged in [5], where the authors state that although a Brooksian behaviour ge..

Adrenal angiosarcoma: report of a case

Adrenal epithelioid angiosarcoma is an extremely rare tumor. Even if such tumors are very aggressive, a long survival may occasionally be observed after an adrenal ectomy. A 70-year-old woman suffering from persistent right flank pain showed a 5-cm right adrenal mass plus a 2-cm liver mass at the radiologic workup, and both were suspected of being malignant. No adrenal hypersecretion was demonstrated. During an explorative median laparotomy the right adrenal gland with the whole periadrenal tissue and locoregional lymph nodes was removed. A histological examination revealed an adrenal angiosarcoma. The resection margin was tumor-free with no lymph node infiltration. The liver mass turned out to be a cistobiliary adenoma. Since no distant metastases were observed, no adjuvant chemotherapy was performed. After an 18-month follow-up the patient is still well with no sign of a relapse. When this rare adrenal tumor is encountered and curative treatment is attempted initially extensive surgical procedures are essential

EFFECT OF SHORT-TERM AND LONG-TERM TREATMENT WITH OMEPRAZOLE ON CELL-CYCLE DISTRIBUTION IN THE GASTRIC-MUCOSA - RESULTS OF A FLOW CYTOMETRIC STUDY

Omeprazole may exert an effect on gastric mucosal proliferation by inhibiting gastric acid secretion and increasing serum gastrin levels. It may also influence the kinetics of endocrine cells and the oxyntic mucosa. The aim of the present study was to evaluate the cell cycle in different gastric compartments following short- (1 month) and long-term (6 months) administration of two different dosages of omeprazole by means of a flow cytometric method. We also determined serum gastrin levels at the same time. No differences in cell cycle distribution of the antrum, body, and fundus were found in the two different dosage groups after 1 month of therapy, considering the synthetic phase (S-phase) of the cell cycle. A statistically significant increase in S-phase was reported after long-term therapy in the mucosa of the fundus and body of the stomach in both groups. Gastrin levels showed no clear correlation with cell cycle distribution variables. We postulate a proliferative adaptation of the oxyntic mucosa to long-term drug administration not mediated by gastrin influence

DNA FLOW CYTOMETRIC EVALUATION OF CELL-CYCLE DISTRIBUTION IN ULCERATIVE-COLITIS - A PROPOSED METHOD FOR ASSESSING SEVERITY OF DISEASE

The assessment of disease severity in ulcerative colitis depends mainly on subjective variables, and an objective method of assessing mucosal inflammation is needed. Determination of the synthetic phase of the cell cycle is an accurate expression of inflammatory activity in the colonic mucosa. The aim of the study was to find out if the proliferative index or the synthetic phase (S phase) of the colonic mucosa of patients with ulcerative colitis, as evaluated by DNA flow cytometry, is a reliable and reproducible marker of disease activity. Sixty consecutive patients with ulcerative colitis of different degrees of activity were entered into the study and submitted to colonoscopy plus multiple rectal biopsies. Disease severity was defined for each patient by means of a clinical, endoscopic, and histological score. Flow cytometry was used to calculate the proliferative index and the S phase of the cell cycle. A statistically significant correlation (p<0.001) was found between all indices of severity. It is suggested that flow cytometric evaluation of the cell cycle in the rectal mucosa may be an efficient method of assessing severity of disease and efficacy of medical treatment in ulcerative colitis