A biologically inspired meta-control navigation system for the Psikharpax rat robot

A biologically inspired navigation system for the mobile rat-like robot named Psikharpax is presented, allowing for self-localization and autonomous navigation in an initially unknown environment. The ability of parts of the model (e. g. the strategy selection mechanism) to reproduce rat behavioral data in various maze tasks has been validated before in simulations. But the capacity of the model to work on a real robot platform had not been tested. This paper presents our work on the implementation on the Psikharpax robot of two independent navigation strategies (a place-based planning strategy and a cue-guided taxon strategy) and a strategy selection meta-controller. We show how our robot can memorize which was the optimal strategy in each situation, by means of a reinforcement learning algorithm. Moreover, a context detector enables the controller to quickly adapt to changes in the environment-recognized as new contexts-and to restore previously acquired strategy preferences when a previously experienced context is recognized. This produces adaptivity closer to rat behavioral performance and constitutes a computational proposition of the role of the rat prefrontal cortex in strategy shifting. Moreover, such a brain-inspired meta-controller may provide an advancement for learning architectures in robotics

Tracking deformable objects with WISARD networks

In this paper, we investigate a new approach based on WISARD Neural Network for the tracking of non-rigid deformable object. The proposed approach allows deploying an on–line training on the texture and shape features of the object, to adapt in real–time to changes, and to partially cope with occlusions. Moreover, the use of parallel classificatory trained on the same set of images allows tracking the movements of the objects. We evaluate our tracking abilities in the scenario of pizza making that represents a very challenging benchmark to test the approach since in this context the shape of the object to track completely changes during the manipulation

Psychometric evaluation supported by a social robot: personality factors and technology acceptance

Robotic psychological assessment is a novel field of research that explores social robots as psychometric tools for providing quick and reliable screening exams. In this study, we involved elderly participants to compare the prototype of a robotic cognitive test with a traditional paper-and-pencil psychometric tool. Moreover, we explored the influence of personality factors and technology acceptance on the testing. Results demonstrate the validity of the robotic assessment conducted under professional supervision. Additionally, results show the positive influence of Openness to experience on the interaction with robot's interfaces, and that some factors influencing technology acceptance, such as Anxiety, Trust, and Intention to use, correlate with the performance in the psychometric tests. Technical feasibility and user acceptance of the robotic platform are also discussed

Single-mode Fiber and Few-Mode Fiber Photonic Lanterns Performance Evaluated for Use in a Scalable Real-Time Photon Counting Ground Receiver

Photonic lanterns provide an efficient way of coupling light from a single large-core fiber to multiple small-core fibers. This capability is of interest for space to ground communication applications. In these applications, the optical ground receivers require high-efficiency coupling from an atmospherically distorted focus spot to multiple fiber coupled single pixel super-conducting nanowire detectors. This paper will explore the use of photonic lanterns in a real-time ground receiver that is scalable and constructed with commercial parts. The number of small-core fibers that make a photonic lantern determines the number of spatial modes that they couple. For instance, lanterns made with n number of single-mode fibers can couple n number of spatial modes. Although the laser transmitted from a spacecraft originates as a Gaussian shape, the atmosphere distorts the beam profile by scattering energy into higher-order spatial modes. Therefore, if a ground receiver is sized for a target data rate with n number of detectors, the corresponding lantern made with single-mode fibers will couple n number of spatial modes. The energy of the transmitted beam scattered into spatial modes higher than n will be lost. This paper shows this loss may be reduced by making lanterns with few-mode fibers instead of single-mode fibers, increasing the number of spatial modes that can be coupled and therefore increasing the coupling efficiency to single pixel, single photon detectors. The free space to fiber coupling efficiency of these two types of photonic lanterns are compared over a range of the free-space coupling numerical apertures and mode field diameters. Results indicate the few mode fiber lantern has higher coupling efficiency for telescopes with longer focal lengths under higher turbulent conditions. Also presented is analysis of the jitter added to the system by the lanterns, showing the few-mode fiber photonic lantern adds more jitter than the single-mode fiber lantern, but less than a multimode fiber

A Minimal Set of Tissue-Specific Hypomethylated CpGs Constitute Epigenetic Signatures of Developmental Programming

Background: Cell specific states of the chromatin are programmed during mammalian development. Dynamic DNA methylation across the developing embryo guides a program of repression, switching off genes in most cell types. Thus, the majority of the tissue specific differentially methylated sites (TS-DMS) must be un-methylated CpGs. Methodology and Principal Findings Comparison of expanded Methyl Sensitive Cut Counting data (eMSCC) among four tissues (liver, testes, brain and kidney) from three C57BL/6J mice, identified 138,052 differentially methylated sites of which 23,270 contain CpGs un-methylated in only one tissue (TS-DMS). Most of these CpGs were located in intergenic regions, outside of promoters, CpG islands or their shores, and up to 20% of them overlapped reported active enhancers. Indeed, tissue-specific enhancers were up to 30 fold enriched in TS-DMS. Testis showed the highest number of TS-DMS, but paradoxically their associated genes do not appear to be specific to the germ cell functions, but rather are involved in organism development. In the other tissues the differentially methylated genes are associated with tissue-specific physiological or anatomical functions. The identified sets of TS-DMS quantify epigenetic distances between tissues, generated during development. We applied this concept to measure the extent of reprogramming in the liver of mice exposed to in utero or early postnatal nutritional stress. Different protocols of food restriction reprogrammed the liver methylome in different but reproducible ways. Conclusion and Significance Thus, each identified set of differentially methylated sites constituted an epigenetic signature that traced the developmental programing or the early nutritional reprogramming of each exposed mouse. We propose that our approach has the potential to outline a number of disease-associated epigenetic states. The composition of differentially methylated CpGs may vary with each situation, behaving as a composite variable, which can be used as a pre-symptomatic marker for disease

Real-time management of water reservoirs with deterministic and ensemble forecasts : the Lake Como case study

LAUREA MAGISTRALEIl Lago di Como, situato nel nord Italia, 'e una delle riserve idriche pi'u importanti del paese. Supporta una grande variet'a di attivit'a antropiche, e viene regolato per soddisfare due obiettivi conflittuali molto importanti: (i) soddisfare il fabbisogno idrico a valle dell'estuario, e allo stesso tempo (ii) prevenire allagamenti lungo le banchine del lago, specialmente nella citt'a di Como. Questo lavoro 'e diretto alla valutazione delle performance di differenti approcci di controllo per la gestione di questa importante risorsa, utilizzando previsioni idrologiche sia deterministiche che probabilistiche ("ensemble"), le quali sono sempre più usate ed accurate. I metodi di controllo oggetto di studio vanno dal "Model Predictive Control" (MPC) deterministico, alla sua relativamente nuova modifica chiamata "Tree Based Model Predictive Control" (TB-MPC), un approccio stocastico che sta ricevendo crescente interesse dalla comunit'a scientifica grazie alla sua maggiore robustezza e adattibilit'a di fronte all'incertezza delle previsioni. Questi controllori predittivi verranno confrontati alla gestione storica e a due approcci off-line di riferimento, chiamati "Stochastic Dynamic Programming" (SDP) e "Deterministic Dynamic Programming" (DDP). MPC e TB-MPC usano previsioni a breve termine dell'afflusso, in particolare MPC usa previsioni deterministiche e TB-MPC probabilistiche sotto forma di "Ensemble forecast" (EF), un insieme di traiettorie deterministiche che rappresenta l'incertezza delle stesse. TB-MPC potrebbe essere un metodo chiave verso il miglioramento della gestione di risorse idriche affrontando meglio le incertezze grazie alla sua natura adattativa. Tuttavia, questi EF non sono sempre disponibili per diversi motivi (per esempio il loro costo, il grande bias, etc.). Questo studio esegue quindi uno dei primi tentativi nella letteratura di sperimentare l'implementazione di TB-MPC con EF sintetici generati con un metodo basato su "machine learning" implementabile operativamente. I risultati delle simulazioni suggeriscono che la regolazione del lago può essere migliorata usando previsioni di qualità in uno schema di controllo in tempo reale. Data l'accuratezza delle previsioni disponibili e di quelle d'ensemble generate, il TB-MPC con frequenza di controllo gionarliera risulta essere il migliore schema per la gestione del Lago di Como tra (TB-)MPC orario/giornaliero, permettendo di considerare l'incertezza delle previsioni nell'ottimizzazione.Lake Como, located in northern Italy, is an important regulated water reservoir supporting a wide range of human activities, and is regulated to satisfy two primary competing objectives: (i) providing water supply to downstream users, mainly farmers and hydropower plants, and (ii) preventing flooding along the lake shores, especially in the city of Como. This work is aimed at assessing the performance of different on-line control approaches for the management of such an important water resource, using both deterministic and probabilistic hydrological forecasts that are increasingly available with better and better accuracy. These are deterministic gls{mpc} and the relatively new stochastic modification called gls{tbmpc}, which has attracted growing interest for its increased robustness and flexibility shown in few previous applications. Their performance is compared to the historical management and to two benchmarks known as gls{ddp} and gls{sdp}, both off-line management approaches. Both MPC and TB-MPC make use of short-term hydrological predictions of the lake inflow: while the MPC uses only deterministic forecasts (here from an operational product), the gls{tbmpc} exploits probabilistic information from an gls{ef}, a set of multiple deterministic predictions that inherently represents the forecast uncertainty. TB-MPC could be a key step towards improving water management to help contrasting the rise of climate-related crises, providing a more adaptive control framework facing uncertainties. However, EFs are not always operationally and readily available at the local scale for different reasons (e.g. high computational cost, lack of local calibration, etc.). So this study has made one of the first attempts in the literature to feed TB-MPC with synthetic EFs from a recently-developed machine learning algorithm that could be used operationally. The simulation results suggest that the lake regulation could be improved by using skilful forecasts in a real-time control scheme. Given the current levels of accuracy of the available forecasts and generated EF, the daily stochastic TB-MPC appeared to be the best on-line control scheme for Lake Como, allowing to use forecasts while considering their uncertainty and consistency

Molecular Alterations and Association with Clinical Parameters

Lynch syndrome is caused by germline mutations of DNA mismatch repair (MMR) genes, most frequently MLH1 and MSH2. Recently, MMR-deficient crypt foci (MMR- DCF) have been identified as a novel lesion which occurs at high frequency in the intestinal mucosa from Lynch syndrome mutation carriers, but very rarely progress to cancer. To shed light on molecular alterations and clinical associations of MMR-DCF, we systematically searched the intestinal mucosa from Lynch syndrome patients for MMR-DCF by immunohistochemistry. The identified lesions were characterised for alterations in microsatellite-bearing genes with proven or suspected role in malignant transformation. We demonstrate that the prevalence of MMR-DCF (mean 0.84 MMR-DCF per 1 cm2 mucosa in the colorectum of Lynch syndrome patients) was significantly associated with patients’ age, but not with patients’ gender. No MMR-DCF were detectable in the mucosa of patients with sporadic MSI-H colorectal cancer (n = 12). Microsatellite instability of at least one tested marker was detected in 89% of the MMR-DCF examined, indicating an immediate onset of microsatellite instability after MMR gene inactivation. Coding microsatellite mutations were most frequent in the genes HT001 (ASTE1) with 33%, followed by AIM2 (17%) and BAX (10%). Though MMR deficiency alone appears to be insufficient for malignant transformation, it leads to measurable microsatellite instability even in single MMR-deficient crypts. Our data indicate for the first time that the frequency of MMR-DCF increases with patients’ age. Similar patterns of coding microsatellite instability in MMR-DCF and MMR-deficient cancers suggest that certain combinations of coding microsatellite mutations, including mutations of the HT001, AIM2 and BAX gene, may contribute to the progression of MMR-deficient lesions into MMR-deficient cancers