Using dialog and human observations to dictate tasks to a learning robot assistant

Robot assistants need to interact with people in a natural way in order to be accepted into people’s day-to-day lives. We have been researching robot assistants with capabilities that include visually tracking humans in the environment, identifying the context in which humans carry out their activities, understanding spoken language (with a fixed vocabulary), participating in spoken dialogs to resolve ambiguities, and learning task procedures. In this paper, we describe a robot task learning algorithm in which the human explicitly and interactively instructs a series of steps to the robot through spoken language. The training algorithm fuses the robot’s perception of the human with the understood speech data, maps the spoken language to robotic actions, and follows the human to gather the action applicability state information. The robot represents the acquired task as a conditional procedure and engages the human in a spoken-language dialog to fill in information that the human may have omitted.     

Sentiment analysis and Twitter: a game proposal

Pervasive sensing of people’s opinions is becoming critical in strategic decision processes, as it may be helpful in identifying problems and strengthening strategies. A recent research trend is to understand users’ opinions through a sentiment analysis of contents published in the Twitter platform. This approach involves two challenges: the large volume of available data and the large variety of used languages combined with the brevity of texts. The former makes manual analysis unreasonable, whereas the latter complicates any type of automatic analysis. Since sentiment analysis is a difficult process for computers, but it is quite simple for humans, in this article, we transform the sentiment analysis process into a game. Indeed, we consider the game with a purpose approach and we propose a game that involves users in classifying the polarity (e.g., positive, negative, neutral) and the sentiment (e.g., joy, surprise, sadness) of tweets. To evaluate the proposal, we used a dataset of 52,877 tweets, we developed a Web-based game, we invited people to play the game, and we validated the results through two different methods: ground-truth and manual assessment. The obtained results showed that the game approach is effective in measuring people’ sentiments and also highlighted that participants liked to play the game.     

Model checking probabilistic systems against pushdown specifications

Model checking is a fully automatic verification technique traditionally used to verify finite-state systems against regular specifications. Although regular specifications have been proven to be feasible in practice, many desirable specifications are non-regular. For instance, requirements which involve counting cannot be formalized by regular specifications but using pushdown specifications, i.e., context-free properties represented by pushdown automata. Research on model-checking techniques for pushdown specifications is, however, rare and limited to the verification of non-probabilistic systems.In this paper, we address the probabilistic model-checking problem for systems modeled by discrete-time Markov chains and specifications that are provided by deterministic pushdown automata over infinite words. We first consider finite-state Markov chains and show that the quantitative and qualitative model-checking problem is solvable via a product construction and techniques that are known for the verification of probabilistic pushdown automata. Then, we consider recursive systems modeled by probabilistic pushdown automata with an infinite-state Markov chain semantics. We first show that imposing appropriate compatibility (visibility) restrictions on the synchronizations between the pushdown automaton for the system and the specification, decidability of the probabilistic model-checking problem can be established. Finally we prove that slightly departing from this compatibility assumption leads to the undecidability of the probabilistic model-checking problem, even for qualitative properties specified by deterministic context-free specifications.     

Improving biped walk stability with complementary corrective demonstration

We contribute a method for improving the skill execution performance of a robot by complementing an existing algorithmic solution with corrective human demonstration. We apply the proposed method to the biped walking problem, which is a good example of a complex low level skill due to the complicated dynamics of the walk process in a high dimensional state and action space. We introduce an incremental learning approach to improve the Nao humanoid robot’s stability during walking. First, we identify, extract, and record a complete walk cycle from the motion of the robot as it executes a given walk algorithm as a black box. Second, we apply offline advice operators for improving the stability of the learned open-loop walk cycle. Finally, we present an algorithm to directly modify the recorded walk cycle using real time corrective human demonstration. The demonstrator delivers the corrective feedback using a commercially available wireless game controller without touching the robot. Through the proposed algorithm, the robot learns a closed-loop correction policy for the open-loop walk by mapping the corrective demonstrations to the sensory readings received while walking. Experiment results demonstrate a significant improvement in the walk stability.     

An unexpected sulfinate–sulfonate mixed coordination polymer of copper(II)

By reaction of copper nitrate trihydrate and 2,2′-dipyridyldisulfide in both aerobic and anaerobic conditions, the mixed [{Cu(2-pySO₂)₂}_n]–[{Cu(2-pySO₃)₂}_n] coordination polymer of copper(II) (1) has been synthesized. The X-ray diffraction analysis indicates that complex 1 exhibits an infinite one-dimensional polymeric chain consisting of [Cu(C₅H₄N)₂] building units connected by SO₂/SO₃ groups. The atom which has been labelled O3 is only present in 60% of the molecules. Complex 1 exhibits a very weak ferrogmagnetic spin coupling (zJ = +0.40 cm⁻¹).     

Protection by different agents against inactivation of lipoxygenase by hydrogen peroxide

H₂O₂ is a potent inactivator of lipoxygenase. In his paper, the ability of different agents [mannitol, oleic, stearic and linoleic acid,n-butanol, and hydroperoxy octadecadienoic acid (HPOD)] to prevent the inactivation of tomato lipoxygenase by hydrogen peroxide has been studied. The involvement of OH^· in the inactivation process is suggested by the ability of mannitol to prevent the loss of activity. This radical would be produced by reaction of H₂O₂ with the Fe(II) lipoxygenase. The most effective protection was displayed by HPOD, the product of the reaction of lipoxygenase with linoleic acid. This result could be explained by the conversion of the native enzyme into the Fe(III) lipoxygenase in the presence of HPOD; the Fe(III) enzyme is not able to react with H₂O₂, and no OH^· will be produced. The protective effect obtained with oleic and stearic acid could be explained by an occupation of the active center by these inhibitors. The enzyme would not transform them, but their presence would hamper the conversion of H₂O₂ in OH^· and limit the damage in the active center.     

Natural perception in dynamic stereoscopic augmented reality environments

Notwithstanding the recent diffusion of the stereoscopic 3D technologies for the development of powerful human computer interaction systems based on augmented reality environment, with the conventional approaches an observer freely moving in front of a 3D display could experience a misperception of the depth and of the shape of virtual objects. Such distortions can cause eye fatigue and stress for entertainment applications, and they can have serious consequences in scientific and medical fields, where a veridical perception of the scene layout is required. We propose a novel technique to obtain augmented reality systems capable to correctly render 3D virtual objects to an observer that changes his/her position in the real world and acts in the virtual scenario. By tracking the positions of the observer’s eyes, the proposed technique generates the correct virtual view points through asymmetric frustums, thus obtaining the correct left and right projections on the screen. The natural perception of the scene layout is assessed through three experimental sessions with several observers.     

Biochemical characteristics of a semi-hard ewe's-milk cheese

Physicochemical, organoleptic and microbiological characteristics of three batches of industrial semihard ewe's milk cheeses were studied over a 90-day ripening period. Cheeses were made with a selected starter containingLactococcus lactis subsp.lactis and subsp.cremoris. The total microbial count was normal throughout manufacture and the ripening period. The level of noncasein nitrogen (NCN) was moderate (23.8% of the total nitrogen, TN) but non-protein nitrogen and amino-acid nitrogen were high: 73.6 (% NCN) and 1.92 (% TN) respectively. Breakdown of _s-(66%) and-caseins (17%) at 90 days provided the cheeses with excellent textural and sensory characteristics.

---

Biochemische Charakteristik eines halbharten Schafskäse

Zusammenfassung Die physiko-chemische, sensorische und mikrobiologische Charakteristik von drei industriellhalb-reifen Schafskäsen wurde während der 90-Tage-Reifungszeit untersucht. Die Käse wurden mit einem ausgewählten Starter mitLactococcus lactis subsp.lactis und subsp.cremoris hergestellt. Die gesamte Keimzahl war während der Herstellung und Reifungszeit normal. Der Nicht-Cascin-Stickstoff (NCN) war mittelmäßig (23,8% des Gesamt-Stickstoffes, TN), aber der Aminosäure-Stickstoff war hoch (73,6% NCN und 1,92% TN). Der Abbau von _s-(66%) und-Cascinen (17%) nach 90 Tagen ist verantwortlich für die gute Texture und Sensorik des Käses.

     

Environmental Impact of Ether Carboxylic Derivative Surfactants

The ultimate aerobic biodegradability and toxicity of three ether carboxylic derivative surfactants having different alkyl chains and degrees of ethoxylation were investigated. Ultimate aerobic biodegradability was screened by means of dissolved organic carbon determinations at different initial surfactant concentrations. For comparison, the characteristic parameters of the biodegradation process, such as half-life, mean biodegradation rate, and residual surfactant concentration, were determined. Increased surfactant concentrations decreased mineralization and lengthened the estimated half-life. The results demonstrate that the ultimate aerobic biodegradability is higher for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. Toxicity values of the surfactants, and their binary mixtures, were determined using three test organisms, the freshwater crustacea Daphnia magna, the luminescent bacterium Vibrio fischeri and the microalgae Selenastrum capricornutum. The toxicity is lower for the surfactants with the shortest alkyl chain and highest degree of ethoxylation. The toxicity of binary mixtures of the three ether carboxylate surfactants at a 1:1 weight ratio was also measured. The least toxic mixture is formed by the surfactants having lower individual toxicity.     

Novel Techniques to Improve Precise Cell Injection

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n > 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.