Identification of Hysteresis Functions Using a Multiple Model Approach

This paper considers the identification of static hysteresis functions which describe phenomena in mechanical systems, piezoelectric actuators and materials. A solution based on a model with a parallel structure of elementary models (with switching) and the Interacting Multiple Model (IMM) approach is proposed. For each elementary model a separate IMM estimator is implemented. The estimated parameters represent a fusion of values from preset grids, weighted by the IMM mode probabilities. The estimated state of each elementary model is a fusion of the estimated states (from the separate Kalman filters) weighted by the IMM probabilities. The nonlinear identification problem is reduced to a linear one. Results from simulation experiments are presented

Local-To-Global Hypotheses for Robust Robot Localization

Many robust state-of-the-art localization methods rely on pose-space sample sets that are evaluated against individual sensor measurements. While these methods can work effectively, they often provide limited mechanisms to control the amount of hypotheses based on their similarity. Furthermore, they do not explicitly use associations to create or remove these hypotheses. We propose a global localization strategy that allows a mobile robot to localize using explicit symbolic associations with annotated geometric features. The feature measurements are first combined locally to form a consistent local feature map that is accurate in the vicinity of the robot. Based on this local map, an association tree is maintained that pairs local map features with global map features. The leaves of the tree represent distinct hypotheses on the data associations that allow for globally unmapped features appearing in the local map. We propose a registration step to check if an association hypothesis is supported. Our implementation considers a robot equipped with a 2D LiDAR and we compare the proposed method to a particle filter. We show that maintaining a smaller set of data association hypotheses results in better performance and explainability of the robot’s assumptions, as well as allowing more control over hypothesis bookkeeping. We provide experimental evaluations with a physical robot in a real environment using an annotated geometric building model that contains only the static part of the indoor scene. The result shows that our method outperforms a particle filter implementation in most cases by using fewer hypotheses with more descriptive power.</p

Automatic Configuration of Multi-Agent Model Predictive Controllers based on Semantic Graph World Models

We propose a shared semantic map architecture to construct and configure Model Predictive Controllers (MPC) dynamically, that solve navigation problems for multiple robotic agents sharing parts of the same environment. The navigation task is represented as a sequence of semantically labeled areas in the map, that must be traversed sequentially, i.e. a route. Each semantic label represents one or more constraints on the robots' motion behaviour in that area. The advantages of this approach are: (i) an MPC-based motion controller in each individual robot can be (re-)configured, at runtime, with the locally and temporally relevant parameters; (ii) the application can influence, also at runtime, the navigation behaviour of the robots, just by adapting the semantic labels; and (iii) the robots can reason about their need for coordination, through analyzing over which horizon in time and space their routes overlap. The paper provides simulations of various representative situations, showing that the approach of runtime configuration of the MPC drastically decreases computation time, while retaining task execution performance similar to an approach in which each robot always includes all other robots in its MPC computations

GPs' reasons for referral of patients with chest pain: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Prompt diagnosis of an acute coronary syndrome is very important and urgent referral to a hospital is imperative because fast treatment can be life-saving and increase the patient's life expectancy and quality of life. The aim of our study was to identify GPs' reasons for referring or not referring patients presenting with chest pain.</p> <p>Methods</p> <p>In a semi-structured interview, 21 GPs were asked to describe why they do or do not refer a patient presenting with chest pain. Interviews were taped, transcribed and qualitatively analysed.</p> <p>Results</p> <p>Histories of 21 patients were studied. Six were not referred, seven were referred to a cardiologist and eight to the emergency department. GPs' reasons for referral were background knowledge about the patient, patient's age and cost-benefit estimation, the perception of a negative attitude from the medical rescue team, recent patient contact with a cardiologist without detection of a coronary disease and the actual presentation of signs and symptoms, gut feeling, clinical examination and ECG results.</p> <p>Conclusion</p> <p>This study suggests that GPs believe they do not exclusively use the 'classical' signs and symptoms in their decision-making process for patients presenting with chest pain. Background knowledge about the patient, GPs' personal ideas and gut feeling are also important.</p

On improving robot image-based visual servoing based on dual-rate reference filtering control strategy

It is well known that the use of multi-rate control techniques have improved the performance of many systems in general, and robotic systems, in particular. The main contribution of this paper is the generalization of the Reference Filtering control strategy from a dual-rate point of view, improving its inherent properties by overcoming the problem of sensor latency. In the paper, we discuss and analyze the improvements introduced by the novel dual-rate reference filtering control strategy in terms of convergence time, reachability and robustness. More specifically, we discuss the capability to solve positioning tasks, when hardware limitations are present with large sampling rates. In addition, a comparison is made between the single-rate and the proposed dual-rate control strategies to prove the advantages of the latter approach. A complete set-up has been prepared for validation, including a six degree of freedom (DOF) industrial manipulator, a smart camera and embedded hardware used as a high level controller.This work was supported by VALi+d Program (Generalitat Valenciana), DIVISAMOS Project (Spanish Ministry, DPI-2009-14744-C03-01), PROMETEO Program (Conselleria d'Educacio, Generalitat Valenciana) and SAFEBUS: Ministry of Economy and Competitivity, IPT-2011-1165-370000).Solanes Galbis, JE.; Muñoz Benavent, P.; Girbés, V.; Armesto Ángel, L.; Tornero Montserrat, J. (2015). On improving robot image-based visual servoing based on dual-rate reference filtering control strategy. Robotica. 1-18. https://doi.org/10.1017/S0263574715000454S11

Antiadhesive Role of Apical Decay-accelerating Factor (CD55) in Human Neutrophil Transmigration across Mucosal Epithelia

Neutrophil migration across mucosal epithelium during inflammatory episodes involves the precise orchestration of a number a cell surface molecules and signaling pathways. After successful migration to the apical epithelial surface, apically localized epithelial proteins may serve to retain PMN at the lumenal surface. At present, identification of apical epithelial ligands and their PMN counter-receptors remain elusive. Therefore, to define the existence of apical epithelial cell surface proteins involved in PMN–epithelial interactions, we screened a panel of antibodies directed against epithelial plasma membranes. This strategy identified one antibody (OE-1) that both localized to the apical cell membrane and significantly inhibited PMN transmigration across epithelial monolayers. Microsequence analysis revealed that OE-1 recognized human decay-accelerating factor (DAF, CD55). DAF is a highly glycosylated, 70–80-kD, glycosyl-phosphatidyinositol–linked protein that functions predominantly as an inhibitor of autologous complement lysis. DAF suppression experiments using antisense oligonucleotides or RNA interference revealed that DAF may function as an antiadhesive molecule promoting the release of PMN from the lumenal surface after transmigration. Similarly, peptides corresponding to the antigen recognition domain of OE-1 resulted in accumulation of PMN on the apical epithelial surface. The elucidation of DAF as an apical epithelial ligand for PMN provides a target for novel anti-inflammatory therapies directed at quelling unwanted inflammatory episodes

Improving detection of surface discontinuities in visual-force control systms

In this paper, a new approach to detect surface discontinuities in a visual–force control task is described. A task which consists in tracking a surface using visual–force information is shown. In this task, in order to reposition the robot tool with respect to the surface it is necessary to determine the surface discontinuities. This paper describes a new method to detect surface discontinuities employing sensorial information obtained from a force sensor, a camera and structured light. This method has proved to be more robust than previous systems even in situations where high frictions occur

Intensive insulin therapy in mixed medical/surgical intensive care units.Benefit vs. harm

Intensywne leczenie insuliną (IIT) poprawia rokowanie u pacjentów w stanie krytycznym długotrwale leczonych na oddziale intensywnej terapii (ICU), natomiast dotychczas nie określono potencjalnych zagrożeń i optymalnego stężenia glikemii. Aby wyjaśnić te wątpliwości, wykorzystano odpowiednią populację dwóch randomizowanych, kontrolowanych badań klinicznych. Niezależnie od ilości glukozy podawanej drogą parenteralną, IIT zmniejszało śmiertelność z 23,6% do 20,4% w grupie intention to treat (n = 2748; p = 0,04) oraz z 37,9% do 30,1% w grupie pacjentów leczonych długotrwale (n = 1389; p = 0,002); nie stwierdzono natomiast istotnej statystycznie różnicy wśród osób leczonych krótkotrwale (8,9% vs. 10,4%; n = 1359; p = 0,4). W porównaniu z glikemią 110-150 mg/dl śmiertelność była znacznie wyższa przy glikemii powyżej 150 mg/dl [wskaźnik ryzyka: 1,38% (95% CI: 1,10-1,75); p = 0,007] i niższa przy glikemii poniżej 110 mg/dl [0,77 (0,61-0,96); p = 0,02]. Jedynie u chorych na cukrzycę (n = 407) nie wykazano poprawy śmiertelności po IIT. Zapobieganie uszkodzeniu nerek i polineuropatia stanów krytycznych stwarzają konieczność utrzymywania stężenia glukozy w ciągu dnia ściśle poniżej 110 mg/dl, co z kolei wiąże się z najwyższym ryzykiem hipoglikemii. W okresie 24 godzin po hipoglikemii zmarło 3 pacjentów leczonych konwencjonalnie i 1 leczony intensywną insulinoterapią (p = 0,0004), bez różnicy w ogólnej śmiertelności szpitalnej. U pacjentów wypisanych z oddziału intensywnej terapii, u których obserwowano hipoglikemię, nie występowały nowe problemy neurologiczne. Stwierdzono, że IIT zmniejsza śmiertelność u wszystkich pacjentów na oddziałach intensywnej terapii zarówno chirurgicznych, jak i internistycznych, z wyjątkiem chorych na cukrzycę, nie powodując istotnych zagrożeń. Docelowe wartości glikemii poniżej 110 mg/dl okazały się najbardziej korzystne w odniesieniu do śmiertelności, ale wiązały się również z największym ryzykiem hipoglikemii.Intensive insulin therapy (IIT) improves the outcome of prolonged critically ill patients, but concerns remain regarding potential harm and the optimal blood glucose level. These questions were addressed using the pooled dataset of two randomized controlled trials. Independent of parenteral glucose load, IIT reduced mortality from 23.6% to 20.4% in the intention-to-treat group (n = 2,748; p = 0.04) and from 37.9% to 30.1% among long stayers (n = = 1.389; p = 0.002), with no difference among short stayers (8.9% vs. 10.4%; n = 1,359; p = 0.4). Compared with blood glucose of 110&#8211;150 mg/dl, mortality was higher with blood glucose > 150 mg/dl [odds ratio 1.38 (95% CI 1.10-1.75); p = 0.007] and lower with < 110 mg/dl [0.77 (0.61-0.96); p = 0.02]. Only patients with diabetes (n = 407) showed no survival benefit of IIT. Prevention of kidney injury and critical illness polyneuropathy required blood glucose strictly < 110 mg/day, but this level carried the highest risk of hypoglycemia. Within 24 h of hypoglycemia, three patients in the conventional and one in the IIT group died (p = 0.0004) without difference in hospital mortality. No new neurological problems occurred in survivors who experienced hypoglycemia in intensive care units (ICUs). We conclude that IIT reduces mortality of all medical/surgical ICU patients, except those with a prior history of diabetes, and does not cause harm. A blood glucose target < 110 mg/day was most effective but also carried the highest risk of hypoglycemia

Predictive ability of an early diagnostic guess in patients presenting with chest pain; a longitudinal descriptive study

The intuitive early diagnostic guess could play an important role in reaching a final diagnosis. However, no study to date has attempted to quantify the importance of general practitioners' (GPs) ability to correctly appraise the origin of chest pain within the first minutes of an encounter. The validation study was nested in a multicentre cohort study with a one year follow-up and included 626 successive patients who presented with chest pain and were attended by 58 GPs in Western Switzerland. The early diagnostic guess was assessed prior to a patient's history being taken by a GP and was then compared to a diagnosis of chest pain observed over the next year. Using summary measures clustered at the GP's level, the early diagnostic guess was confirmed by further investigation in 51.0% (CI 95%; 49.4% to 52.5%) of patients presenting with chest pain. The early diagnostic guess was more accurate in patients with a life threatening illness (65.4%; CI 95% 64.5% to 66.3%) and in patients who did not feel anxious (62.9%; CI 95% 62.5% to 63.3%). The predictive abilities of an early diagnostic guess were consistent among GPs. The GPs early diagnostic guess was correct in one out of two patients presenting with chest pain. The probability of a correct guess was higher in patients with a life-threatening illness and in patients not feeling anxious about their pain