A universal robot control system (URCS) based on the TUNISmultiprocessor

The design and development of a universal robot control system (URCS) that would enable computation-intensive control algorithms to be implemented and modified is reported. This required shifting from hardware to software, using high-performance computing platforms. In general, multiprocessing has been found to be a cost-effective method for increasing performance, especially when the control algorithm can be composed into concurrent computational tasks. The URCS was developed using the University of Toronto Multiprocessor System (TUNIS) as the computing platform. One processor reads sensors, another calculates compensation signals and commands to the motors, a third is designated for operator requests, and the last is used for the operating system. An interface that allows the URCS to control the PUMA 560 robot was designed and built     

Variables influencing tumor dosimetry in radioimmunotherapy of CEA-expressing cancers with anti-CEA and antimucin monoclonal antibodies

In this study, we examined the factors that may influence tumor dosimetry in the radioimmunotherapy of solid, CEA-expressing cancers. METHODS: Data from 119 tumors in 93 patients with CEA-expressing cancers were analyzed. The patients underwent radioimmunotherapy with the 131I-labeled IgG1 anti-CEA antibodies NP-4 (Ka = 10(8) M-1) or MN-14 (Ka = 10(9) M-1), its humanized form hMN-14, as well as the anticolon-specific antigen-p (CSAp) antibody, Mu-9. For dosimetry, the biodistribution, targeting kinetics and cumulated activity of tumors and organs were determined from planar and SPECT imaging. RESULTS: An inverse logarithmic relationship between tumor size and antibody uptake was found for both anti-CEA antibodies, whereas no such relationship was found for Mu-9. The absolute tumor uptake was identified as the most important factor determining the radiation dose to the tumor (r = 0.9), with the biological half-life of the antibody in the tumor being of secondary importance (r = 0.5). No significant difference in tumor uptake was found between both anti-CEA antibodies, despite their tenfold difference in affinity. At comparable masses, colorectal and medullary thyroid cancers had significantly higher tumor uptakes (p = 0.02), as well as tumor-to-red marrow dose ratios, than other cancer types. The tumor half-lives of the anti-CEA antibodies were significantly lower in colorectal than in all other tumor types (p = 0.01). CONCLUSION: In radioimmunotherapy, tumor uptake appears to be the most important dose-determining factor. Differences in antibody affinity are reflected by differences in the biological half-life, not the absolute uptake. Especially favorable conditions for anti-CEA antibodies seem to prevail in colorectal cancer patients having minimal disease, as well as in medullary thyroid cancer, where cytotoxic tumor doses might be expected. Antimucin antibodies may have a particular advantage in the treatment of patients with larger colorectal tumors.     

Energy spectra of electrons and depressed potential collector in gyrotrons

Energy distributions of electrons after their interaction with RF field in the gyrotron with the output power 1 MW and frequency 140 GHz are calculated. The energy spectra evolution is studied for the cases when velocity spread, pitch-factor, beam current and cyclotron frequency change. The efficiency of one- and two stage energy recovery systems are investigated.     

Tool use and mechanical problem solving in apraxia

Moorlaas (1928) proposed that apraxic patients can identify objects and can remember the purpose they have been made for but do not know the way in which they must be used to achieve that purpose. Knowledge about the use of objects and tools can have two sources: It can be based on retrieval of instructions of use from semantic memory or on a direct inference of function from structure. The ability to infer function from structure enables subjects to use unfamiliar tools and to detect alternative uses of familiar tools. It is the basis of mechanical problem solving. The purpose of the present study was to analyze retrieval of instruction of use, mechanical problem solving, and actual tool use in patients with apraxia due to circumscribed lesions of the left hemisphere. For assessing mechanical problem solving we developed a test of selection and application of novel tools. Access to instruction of use was tested by pantomime of tool use. Actual tool use was examined for the same familiar tools. Forty two patients with left brain damage (LBD) and aphasia, 22 patients with right brain damage (RBD) and 22 controls were examined. Only LBD patients differed from controls on all tests. RBD patients had difficulties with the use but not with the selection of novel tools. In LBD patients there was a significant correlation between pantomime of tool use and novel tool selection but there were single cases who scored in the defective range on one of these tests and normally on the other. Analysis of LBD patients' lesions suggested that frontal lobe damage does not disturb novel tool selection. Only LBD patients who failed on pantomime of object use and on novel tool selection committed errors in actual use of familiar tools. The finding that mechanical problem solving is invariably defective in apraxic patients who commit errors with familiar tools is in good accord with clinical observations, as the gravity of their errors goes beyond what one would expect as a mere sequel of loss of access to instruction of use.     

Heavy snoring with upper airway resistance syndrome may induce intrinsic positive end-expiratory pressure

We studied eight heavy snorers with upper airway resistance syndrome to investigate potential effects of sleep on expiratory airway and lung resistance, intrinsic positive end-expiratory pressure, hyperinflation, and elastic inspiratory work of breathing (WOB). Wakefulness and non-rapid-eye-movement sleep with high- and with low-resistance inspiratory effort (H-RIE and L-RIE, respectively) were compared. No differences in breathing pattern were seen across the three conditions. In contrast, we found increases in expiratory airway and lung resistance during H-RIE compared with L-RIE and wakefulness (56 +/- 24, 16 +/- 4, and 11 +/- 4 cmH2O . 1(-1) . s, respectively), with attendant increases in intrinsic positive end-expiratory pressure (5.4 +/- 1.8, 1.4 +/- 0.5, and 1.3 +/- 1.3 cmH2O, respectively) and elastic WOB (6.1 +/- 2.2, 3.7 +/- 1.2, and 3.4 +/- 0.7 J/min, respectively). The increase in WOB during H-RIE is partly caused by the effects of dynamic pulmonary hyperinflation produced by the increased expiratory resistance. Contrary to the Starling model, a multiple-element compliance model that takes into account the heterogeneity of the pharynx may explain flow limitation during expiration.     

AHP-Based Equipment Selection Model for Construction Projects

Selection of equipment for construction projects, a key factor in the success of the project, is a complex process. Current models offered by the literature fail to provide adequate solutions for two major issues: the systematic evaluation of soft factors, and the weighting of soft benefits in comparison with costs. This paper presents a selection model based on analytic hierarchy process (AHP), a multiattribute decision analysis method, with a view to providing solutions for these two issues. The model has the capacity to handle a great number of different criteria in a way that truly reflects the complex reality, to incorporate the context and unique conditions of the project, and to allow for manifestation of user experience and subjective perception. The model was implemented in an in-house developed system that was improved and validated through testing by senior professionals. The main academic contribution of the study is in the modification of AHP to correspond with the nature of equipment selection and in its utilization as an effective means for the formalization of knowledge possessed by competent, experienced practitioners. On the practical side, the proposed model offers an efficient, convenient tool that forces the users into orderly, methodical thinking, guides them in making logical, consistent decisions, and provides a facility for all necessary computations.     

Visual correlation of network alerts

The VisAlert visual correlation tool facilitates situational awareness in complex network environments by providing a holistic view of network security to help detect malicious activities. Information visualization techniques and methods in many applications have effectively increased operators' situational awareness, letting them more effectively detect, diagnose, and treat anomalous conditions. Visualization elevates information comprehension by fostering rapid correlation and perceived associations. Our visualization technique integrates the information in log and alert files into an intuitive, flexible, extensible, and scalable visualization tool - VisAlert - that presents critical information concerning network activity in an integrated manner, increasing the user's situational awareness.     

Implementation of robust impedance and force control

In this paper, we discuss the problem of implementing impedance control in the presence of model uncertainties and its application to robot force control. We first propose a sliding mode-based impedance controller. The implementation of the targeted impedance, and the preservation of stability in the presence of model uncertainties, are the key issues in the proposed approach. Using sliding mode control, a simple and robust algorithm is obtained so that the targeted impedance can be accurately implemented without the exact model of the robot. The controller is designed in terms of the task space coordinates. The chattering in the sliding mode control is eliminated by using a continuous function. The problem of force control is also addressed for the impedance controlled robot. An off-line estimation method of the environment model is suggested and used in the force control scheme. The proposed impedance and force control schemes have been experimentally verified on a two degree-of-freedom direct-drive robot arm. The experimental results are presented in this paper.