The State of Lifelong Learning in Service Robots: Current Bottlenecks in Object Perception and Manipulation

Service robots are appearing more and more in our daily life. The development of service robots combines multiple fields of research, from object perception to object manipulation. The state-of-the-art continues to improve to make a proper coupling between object perception and manipulation. This coupling is necessary for service robots not only to perform various tasks in a reasonable amount of time but also to continually adapt to new environments and safely interact with non-expert human users. Nowadays, robots are able to recognize various objects, and quickly plan a collision-free trajectory to grasp a target object in predefined settings. Besides, in most of the cases, there is a reliance on large amounts of training data. Therefore, the knowledge of such robots is fixed after the training phase, and any changes in the environment require complicated, time-consuming, and expensive robot re-programming by human experts. Therefore, these approaches are still too rigid for real-life applications in unstructured environments, where a significant portion of the environment is unknown and cannot be directly sensed or controlled. In such environments, no matter how extensive the training data used for batch learning, a robot will always face new objects. Therefore, apart from batch learning, the robot should be able to continually learn about new object categories and grasp affordances from very few training examples on-site. Moreover, apart from robot self-learning, non-expert users could interactively guide the process of experience acquisition by teaching new concepts, or by correcting insufficient or erroneous concepts. In this way, the robot will constantly learn how to help humans in everyday tasks by gaining more and more experiences without the need for re-programming

Effects of rigid and non-rigid image registration on test-retest variability of quantitative [18F]FDG PET/CT studies

ABSTRACT: BACKGROUND: [18F]fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography (PET) is a valuable tool for monitoring response to therapy in oncology. In longitudinal studies, however, patients are not scanned in exactly the same position. Rigid and non-rigid image registration can be applied in order to reuse baseline volumes of interest (VOI) on consecutive studies of the same patient. The purpose of this study was to investigate the impact of various image registration strategies on standardized uptake value (SUV) and metabolic volume test-retest variability (TRT). METHODS: Test-retest whole-body [18F]FDG PET/CT scans were collected retrospectively for 11 subjects with advanced gastrointestinal malignancies (colorectal carcinoma). Rigid and non-rigid image registration techniques with various degrees of locality were applied to PET, CT, and non-attenuation corrected PET (NAC) data. VOI were drawn independently on both test and retest scans. VOI drawn on test scans were projected onto retest scans and the overlap between projected VOI and manually drawn retest VOI was quantified using the Dice similarity coefficient (DSC). In addition, absolute (unsigned) differences in TRT of SUVmax, SUVmean, metabolic volume and total lesion glycolysis (TLG) were calculated in on one hand the test VOI and on the other hand the retest VOI and projected VOI. Reference values were obtained by delineating VOIs on both scans separately. RESULTS: Non-rigid PET registration showed the best performance (median DSC: 0.82, other methods: 0.71-0.81). Compared with the reference, none of the registration types showed significant absolute differences in TRT of SUVmax, SUVmean and TLG (p > 0.05). Only for absolute TRT of metabolic volume, significant lower values (p < 0.05) were observed for all registration strategies when compared to delineating VOIs separately, except for non-rigid PET registrations (p = 0.1). Non-rigid PET registration provided good volume TRT (7.7%) that was smaller than the reference (16%). CONCLUSION: In particular, non-rigid PET image registration showed good performance similar to delineating VOI on both scans separately, and with smaller TRT in metabolic volume estimates.van Velden F.H.P., van Beers P., Nuyts J., Velasquez L.M., Hayes W., Lammertsma A.A., Boellaard R., Loeckx D., ''Effects of rigid and non-rigid image registration on test-retest variability of quantitative [18F]FDG PET/CT studies'', EJNMMI research, vol. 2, no. 10, 2012.status: publishe

The State of Service Robots:Current Bottlenecks in Object Perception and Manipulation

Service robots are appearing more and more in our daily life. The development of service robots combines multiple fields of research, from object perception to object manipulation. The state-of-the-art continues to improve to make a proper coupling between object perception and manipulation. This coupling is necessary for service robots not only to perform various tasks in a reasonable amount of time but also to adapt to new environments through time and interact with non-expert human users safely. Nowadays, robots are able to recognize various objects, and quickly plan a collision-free trajectory to grasp a target object. While there are many successes, the robot should be painstakingly coded in advance to perform a set of predefined tasks. Besides, in most of the cases, there is a reliance on large amounts of training data. Therefore, the knowledge of such robots is fixed after the training phase, and any changes in the environment require complicated, time-consuming, and expensive robot re-programming by human experts. Therefore, these approaches are still too rigid for real-life applications in unstructured environments, where a significant portion of the environment is unknown and cannot be directly sensed or controlled. In this paper, we review advances in service robots from object perception to complex object manipulation and shed a light on the current challenges and bottlenecks

Mechanism of nitrite oxidation by eosinophil peroxidase: implications for oxidant production and nitration by eosinophils

Eosinophil peroxidase is a haem enzyme of eosinophils that is implicated in oxidative tissue injury in asthma. It uses hydrogen peroxide to oxidize thiocyanate and bromide to their respective hypohalous acids. Nitrite is also a substrate for eosinophil peroxidase. We have investigated the mechanisms by which the enzyme oxidizes nitrite. Nitrite was very effective at inhibiting hypothiocyanous acid (‘cyanosulphenic acid’) and hypobromous acid production. Spectral studies showed that nitrite reduced the enzyme to its compound II form, which is a redox intermediate containing Fe(IV) in the haem active site. Compound II does not oxidize thiocyanate or bromide. These results demonstrate that nitrite is readily oxidized by compound I, which contains Fe(V) at the active site. However, it reacts more slowly with compound II. The observed rate constant for reduction of compound II by nitrite was determined to be 5.6×10(3) M(−1)·s(−1). Eosinophils were at least 4-fold more effective at promoting nitration of a heptapeptide than neutrophils. This result is explained by our finding that nitrite reacts 10-fold faster with compound II of eosinophil peroxidase than with the analogous redox intermediate of myeloperoxidase. Nitration by eosinophils was increased 3-fold by superoxide dismutase, which indicates that superoxide interferes with nitration. We propose that at sites of eosinophilic inflammation, low concentrations of nitrite will retard oxidant production by eosinophil peroxidase, whereas at higher concentrations nitrogen dioxide will be a major oxidant formed by these cells. The efficiency of protein nitration will be decreased by the diffusion-controlled reaction of superoxide with nitrogen dioxide

Macrophage imaging in central nervous system and in carotid atherosclerotic plaque using ultrasmall superparamagnetic iron oxide in magnetic resonance imaging

SCOPUS: re.jinfo:eu-repo/semantics/publishe

In Vivo Morphological Changes in Animal Models of Amyotrophic Lateral Sclerosis and Alzheimer's-Like Disease: MRI Approach

Magnetic resonance imaging (MRI) is the only noninvasive technique that provides structural information on both cell loss and metabolic changes. After reviewing all the results obtained in clinical studies, reliable biomarkers in neurological diseases are still lacking. Diffusional MRI, MR spectroscopy, and the assessment of regional atrophy are promising approaches, but they cannot be simultaneously used on a single patient. Thus, for further research progress, reliable animal models are needed. To this aim, we have used the clinical MRI to assess neurodegenerative processes in the hSOD-1G93A ALS rat model and in the trimethyltin (TMT)-treated model of Alzheimer's-like disease. T2-weighted (T2W) hyperintensive neurodegenerative foci were found in the brainstem of the ALS rat with apparent lateral ventricle dilation (T1W - hypointensity vs. T2W - hyperintensity). Degenerative processes in these areas were also confirmed by confocal images of GFAP-positive astrogliosis. MRI after i.v.i. of magnetic anti-CD4 antibodies indicated an accumulation of inflammatory cells near dilated ventricles. TMT-treated rats also revealed the dilation of lateral ventricles. Expected deterioration in the hippocampus was not observed by clinical MRI, but immunocytochemistry could reveal significant redistribution of macro- and microglia in this structure. In both models, Gd-DTPA contrast revealed a compromised blood brain barrier that may serve as the passage for inflammatory immune cells in the vicinity of dilated lateral ventricles. Moreover, in both models the midbrain region of the dorsal hippocampus was the target of BBB compromise, thus revealing a potentially vulnerable point that can be the primary target of neurodegeneration in the central nervous system. Anat Rec, 292:1882-1892, 2009. © 2009 Wiley-Liss, Inc.FLWINinfo:eu-repo/semantics/publishe

Elaboration during problem-based group discussion: Effects on recall for high and low ability students

Item does not contain fulltextAlthough elaboration has been investigated frequently, there is little evidence for the beneficial effect of elaboration in problem-based learning. A controlled experiment tested the effect of elaboration during problem-based discussion on recall. Sixty-seven students observed a video-recorded, problem-based discussion. In one experimental condition, a tutor in the video encouraged participants to elaborate by asking elaborative questions. In a second condition, the tutor asked superficial questions. After the discussion, all participants studied a text with relevant new information. Elaborative questions had no significant effect on recall of idea units from the text, p = .39, eta(2) = .01. High-ability students outperformed low-ability students, p = .04, eta(2) = .07, but this effect did not interact with the experimental treatment, p = .22, eta(2) = .02. Suggestions for further research are presented