Simultaneous localization and map-building using active vision

An active approach to sensing can provide the focused measurement capability over a wide field of view which allows correctly formulated simultaneous localization and map-building (SLAM) to be implemented with vision, permitting repeatable longterm localization using only naturally occurring, automatically-detected features. In this paper, we present the first example of a general system for autonomous localization using active vision, enabled here by a high-performance stereo head, addressing such issues as uncertainty-based measurement selection, automatic map-maintenance, and goal-directed steering. We present varied real-time experiments in a complex environment     

Judging it Department Performance

Based on a lengthy career as an IT project manager and consultant, the author has come to recognize the importance of processes that provide an objective assessment of IT's actual performance. He also experienced that in too many organizations, opinions instead of assessments hold sway. This article explains how to overcome these uninformed biases, objectively judge IT, and use this assessment as part of a continuous improvement process.     

Respiratory symptoms and lung function in aborigines from tropical Western Australia

To estimate the prevalence of respiratory symptoms, bronchial hyperresponsiveness, smoking, and atopy in a population of Australians of Aboriginal descent (AAD), to determine the association of these and other factors with lung function, and to compare levels of lung function of AAD with Australians of European descent (AED) according to age and height, and to explore reasons for their differences, we conducted a study of 96 male (41 of whom were under 18 yr of age) and 111 female (48 of whom were under 18 yr of age) AAD living in a single remote tropical community in 1993. This population provided data on age, height, and lung function. A modified British Medical Research Council (MRC) questionnaire on respiratory symptoms and smoking was administered. FEV1, FVC, height, age, and bronchial responsiveness to inhaled methacholine were measured. Atopic status was assessed by skin prick tests for eight common allergens. Age- and sex-adjusted lung function was similar to that of other AAD groups and lower than in AED. For children, lung function increased less with increasing height in AAD than in AED. Lung function was reduced in adult AAD as compared with adult AED, although it was not possible to determine statistically whether lung function started to decline at an earlier age or declined faster with increasing age in AAD. A history of asthma, smoking, dyspnea, cough, or sputum production; atopic status; and increased bronchial responsiveness were all associated with lower levels of lung function. Differences in lung function between AAD and AED appear to be determined by characteristics that may be inherited, as well as by adverse external influences.     

Evaluation of optimized compensators on a 3D planning system

A commercially available treatment planning system contains several functions that allow for the automation of missing tissue and optimized compensators, where the former retracts the bolus toward the source, and the latter attempts, by iteration, to establish a uniform dose at some user defined depth. The intent of this paper is to report on the compensators designed by the system and to compare them to those devised through conventional techniques. It is demonstrated that the system can model the dosimetric effects of compensators with a high degree of accuracy; measured and predicted doses agree to within 3%. Optimized compensators show slightly improved dose uniformity over thickness reduced compensators. Both show significantly improved uniformity over compensators that simply retract the bolus geometry. In cases where internal inhomogeneities exist, however, the dose uniformity from the optimized compensators vary by as much as 6% at the target depth. These deviations are comparable to the errors of the inhomogeneity algorithm itself. The pathlength reduction technique has been applied to both missing tissue and inhomogeneity compensation, and it has been found that for inhomogeneity compensation, the pathlength reduced compensators produce more uniform distributions than those generated by the optimization algorithm.     

Distributed algorithms for cooperative control

Expressing a cooperative control system requires combining tools from control theory and distributed computation. After reviewing several possible formalisms appropriate for the job, the authors settle on the computation and control language and illustrate its main features and advantages using a cooperative tracking task. We demonstrate some of the concepts involved in using a multirobot task. We also discuss CCL's ability to be a programming language as well as a modeling tool, which lets us directly simulate or execute CCL models.     

Metabolism of n−3 polyunsaturated fatty acids by the isolated perfused rat liver

The hepatic metabolism of oleic acid and n−3 fatty acids (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA), and secretion of very low density lipoprotein (VLDL) were studied in isolated perfused rat livers from normal chow fed male rats. The basal perfusion medium contained 30% bovine erythrocytes, 6% bovine serum albumin (BSA), and 100 mg/dL glucose, in Krebs-Henseleit bicarbonate buffer (pH 7.4) which was recycled through the liver for 2 hr. Individual fatty acids (EPA, DHA or oleic acid), as complexes with 6% BSA, or albumin alone, were infused at a rate of 70 μmol/hr. When any of these fatty acids was infused at this rate, the ambient concentration in the medium was maintained at 0.3–0.4 μmol/mL, indicative of similar hepatic rates of uptake for each fatty acid (i.e., approximately 6 μmol/g liver/hr). When fatty acid was not infused, the ambient free fatty acid level was 0.16 μmol/mL. The concentrations of infused free fatty acids increased appropriately in the perfusion medium; however, with infusion of EPA, DHA, or oleate, the concentrations of perfusate palmitate and linoleate were the same as when fatty acid was not infused. Additionally, the perfusate concentration of oleate in the free fatty acid fraction was not affected by infusion of EPA and DHA. These data indicate a constant outflow of endogenous fatty acid unaffected by the presence of the exogenously supplied fatty acid. The net secretion rate of VLDL lipids and protein was stimulated by infusion of oleate, whereas when EPA was infused, secretion rates were lower and similar [except for VLDL cholesterol (C), which was greater] to those occuring when fatty acid was not provided. DHA stimulated the secretion of VLDL triacylglycerol (TG), phospholipid (PL) and C to a similar rate, as did oleate, but secretion of VLDL cholesteryl ester (CE) and protein was lower and similar to that with EPA. VLDL and hepatic TG and CE were enriched with the infused fatty acids, compared to experiments without fatty acids, as determined by gas chromatography. Enrichment of PL, however, was significant only in liver upon infusion of EPA. The formation of¹⁴CO₂ and perchloric acid soluble products from [1-¹⁴C]EPA, considered separately, did not differ statistically from that obtained with [1-¹⁴C]oleate, although the mean values were higher with [1-¹⁴C]EPA. However, the sum of oxidation products derived from EPA was significantly greater than that from oleate. Incorporation of [1-¹⁴C]EPA into TG and CE, but not into PL, was lower as compared to that from [1-¹⁴C]oleate. These lower rates of incorporation of [1-¹⁴C]EPA into VLDL lipids therefore paralleled the mass fatty acid enrichment-patterns. It may be concluded that EPA is used to a similar extent as oleate for synthesis of PL, but is a poorer substrate for synthesis of TG. The reduced output of newly synthesized (radioactive) PL reflected the lower hepatic output of VLDL. Since hepatic uptake of EPA, DHA or oleate was identical, utilization of EPA for TG synthesis was less than that of oleate or DHA. Further-more, utilization of endogenous fatty acids for TG synthesis and secretion of the VLDL was reduced in the presence of EPA. The decreased TG synthesis resulted in reduced formation of VLDL for transport of TG from the liver. These effects taken together with an apparently increased oxidation of EPA provide substantial evidence for a decrease in formation of VLDL and transport of TG, PL, C and CE into the circulation in response to EPA. DHA, however, appears to be an adequate substrate for TG synthesis and stimulates VLDL secretion. The reduced transport of CE may reflect lower selectivity of DHA by acyl-CoA; cholesterol acyltransferase for CE formation.     

Semantic communication and expectations for counseling across three theoretical orientations.

Using excerpts taken from 2 time periods in each interview from the film series, Three Approaches to Psychotherapy, the language of the counselors (C. Rogers, F. Perls, and A. Ellis) and the client was compared to determine whether relations exist between participants' speech in the interview and the counselor's prior stated intentions for the interaction. Language was analyzed by means of the Computer-Assisted Language Analysis System; the dependent measures were verb phrases classified into types of inherent semantic relators. Counselors differed significantly in their use of verb phrases defining (a) states or properties of objects, (b) actions initiated by agents, and (c) a compound of experiential states and actions. In contrast, the client's language was remarkably consistent from interview to interview, with 1 exception: The client's use of verbs defining experience was significantly more frequent when talking with Rogers than when talking with Ellis. Results are discussed in terms of how structural analyses of language may help counselors (a) identify treatment policies mutually formulated and implemented at different stages of the counseling process and (b) relate these policies to the needs of clients whose cultural background is different from that of the counselor. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stress-corrosion cracking of reactor feed pump wear rings

Stress-corrosion cracking (SCC) is observed in machine components when an optimal combination of stress levels and environmental conditions is present in susceptible material. An interesting case history of intergranular SCC failure is presented in this paper. This failure occurred in wear rings that were shrink-fitted on the impellers of a multistage horizontal feed pump during the project procurement phase. After manufacture and assembly, two pumps were performance-tested in the supplier's test loop for a combined total of approximately 600 h. The test duration lasted for approximately three months. During this duration, the two pump internals were not absolutely dry and were exposed to an indoor environment in the supplier's test plant. After the completion of the tests, the pump internals were inspected, cleaned, dried, and packaged before air freighting to the reactor site. The pumps were in storage at the site for approximately two months. When the pumps were opened for inspection, two wear rings on each of the pumps were cracked. This paper summarizes the results of the studies to evaluate the root cause of the wear ring failures and the corrective actions implemented to avoid similar failures.     

Grouping in Short-Term Memory: Do Oscillators Code the Positions of Items?

According to several current models of short-term memory, items are retained in order by associating them with positional codes. The models differ as to whether temporal oscillators provide those codes. The authors examined errors in recall of sequences comprising 2 groups of 4 consonants. A critical manipulation was the precise timing of items within the groups, whereby temporal position (time from group onset) and ordinal position (number of items from group onset) were partially unconfounded. Errors that involve items migrating across groups should preserve within-group temporal position according to oscillator models, but should preserve within-group ordinal position according to nonoscillator models. Results from the intergroup errors strongly favored preservation of ordinal rather than temporal position. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Six Regularities of Source Recognition.

In recent work, researchers have shown that source-recognition memory can be incorporated in an extended signal detection model that covers both it and item-recognition memory (A. Hilford, M. Glanzer, K. Kim, & L. T. DeCarlo, 2002). In 5 experiments, using learning variables that have an established effect on item recognition, the authors tested further implications of that extended model. The results establish 6 source-recognition regularities that support the model. An important regularity in that set is the linkage of source and item recognition: Any learning variable that increases item recognition increases source recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)