Robotic sensorimotor interaction strategies

Abstract. In this thesis we investigate the mathematical modeling of cognition using sensorimotor transition systems. The focus of the thesis is enactivism, where an agent learns to think through actions. As a theoretical basis for our implementation, we discuss a mathematical model of enactivist cognition, sensorimotor interaction and how they can be used as algorithmic aides for studying theoretical problems in robotic systems. In Chapter 3 of this thesis, we introduce a platform which was developed in the University of Oulu as a software project and explain how enactivism and sensorimotor interaction have been taken advantage of, in developing a 2D platform. This platform enables one to concretely implement and explore different interaction strategies that allow an agent to construct internal models of its surroundings. The agent in the platform is a multi-jointed robotic arm, which maneuvers through an obstacle-filled environment. The robotic arm tries to explore its environment with minimal sensory feedback, using algorithms created by the user of the platform. Our main goal on this thesis is to implement new features to this platform. We implement a memory functionality which allows the robotic arm to store all its performed actions. The memory helps the agent infer to a greater extent its surroundings from a limited sequence of action-observation pairs, and helps it in getting a better grasp of the environment. In addition, we implement other methods and functionalities, such as an obstacle sensor, a graph visualization of the internal models, etc. to enhance the perceptual ability of the robotic arm. In Section 5, we develop an algorithm for a simple 2D environment with no obstacles. Here the robotic arm makes a 360-degree move in four steps to perceive its surroundings and generates a state machine graph to visualize its internal model of the environment. The goal of the algorithm is to build an accurate representation of the environment with the help of memory. Through this algorithm we are able to evaluate the performance of the newly implemented features. We also test the platform through unit testing for finding and resolving bugs.Sensorimotoriset vuorovaikutusstrategiat robotiikassa. Tiivistelmä. Tässä tutkielmassa tutkimme kognition matemaattista mallintamista käyttämällä sensorimotorisia transitio-järjestelmiä. Tutkielman keskiössä on enaktivismi, jossa agentti oppii ajattelemaan toiminnan kautta. Teoreettisena perustana toteutuksellemme käsittelemme matemaattista mallia enaktivistisesta kognitiosta, sensorimotorista vuorovaikutusta ja kuinka niitä voidaan käyttää algoritmien apuvälineinä teoreettisten ongelmien tutkimisessa robottiikkajärjestelmissä. Tutkielman luvussa 3 esittelemme alustan, joka on kehitetty Oulun yliopistossa ohjelmistoprojektina, ja selittämme miten enaktivismia ja sensomotorista vuorovaikutusta on hyödynnetty 2D-alustan kehittämisessä. Alusta mahdollistaa erilaisten vuorovaikutusstrategioiden konkreettisen toteuttamisen ja tutkimisen. Näiden avulla agentti rakentaa sisäisiä malleja ympäristöstään. Alustassa mallinnettu agentti on moninivelinen robottikäsi, joka liikkuu esteitä sisältävässä ympäristössä. Robottikäsi pyrkii tutkimaan ympäristöään minimaalisen sensoritiedon avulla käyttämällä alustan käyttäjän luomia algoritmeja. Tutkielmamme päätavoite on kehittää uusia ominaisuuksia tälle alustalle. Toteutamme muistitoiminnallisuuden, jonka avulla robottikäsi tallentaa kaikki suoritetut toiminnot. Muisti auttaa agenttia päättelemään enemmän ympäristöstään rajoitettujen toiminta-havainto-parien avulla, ja auttaa sitä ympäristön hahmottamisessa. Lisäksi kehitämme muita menetelmiä ja toiminnallisuuksia kuten estesensorin ja sisäisten mallien graafisen visualisoinnin parantaaksemme robottikäden havainnointikykyä. Tutkielman myöhemmässä osassa kehitämme algoritmin yksinkertaiselle 2D-ympäristölle ilman esteitä. Siinä robottikäsi tekee 360 asteen liikkeen neljässä vaiheessa havainnoidakseen ympäristönsä, ja luo tilasiirtymäkaavion visualisoidakseen sisäisen mallinsa ympäristöstä. Algoritmin tavoitteena on rakentaa tarkka malli ympäristöstä muistin avulla. Tämän algoritmin avulla pystymme arvioimaan kehittämiemme uusien ominaisuuksien toimintaa. Testaamme alustaa myös yksikkötesteillä löytääksemme ja korjataksemme virheitä

Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion Associated with Systemic Mycoplasma pneumoniae Infection in North America: A Case Report

BACKGROUND: Mild encephalitis/encephalopathy with reversible splenial lesion is a clinical-radiological entity found to occur in the setting of an acute systemic inflammatory state with isolated lesions of the splenium of the corpus callosum and mild encephalopathy. Mild encephalitis/encephalopathy with reversible splenial lesion is commonly found to occur in children in the setting of viral infections. It has rarely been associated with Mycoplasma pneumoniae in the United States, unlike in Eastern and Southern Asia where this is much more prominent. CASE PRESENTATIONS: A 5-year-old African-American boy with autism spectrum disorder presented to our emergency department with acute onset intractable vomiting, diarrhea, and abnormal tensing movements for 2 days, following a 6-day period of fatigue, fever, and spastic abdominal pain. Emergent work-up in our department ruled out acute gastrointestinal pathologies. Given the high fevers and encephalopathy, there was concern for meningitis or encephalitis. His cerebrospinal fluid profile was concerning for viral meningitis, however extensive infectious workup was negative. Magnetic resonance imaging of his brain demonstrated a T2 fluid-attenuated inversion recovery sequence hyperintensity in the splenium of the corpus callosum, read as postictal changes by radiology. Continuous video electroencephalography demonstrated mild diffuse encephalopathy without electrographic correlate of his tensing episodes. He was determined to have mild encephalitis/encephalopathy with a reversible splenial lesion in the setting of a postinfectious etiology. He was treated with a single pulse-dose of intravenous methylprednisolone, following which he gradually returned to his baseline the next day. Repeat magnetic resonance imaging and cerebrospinal fluid evaluation demonstrated resolution of previous findings. He was ultimately diagnosed with an acute M. pneumoniae infection, which was determined to be the etiology of his mild encephalitis/encephalopathy with a reversible splenial lesion. CONCLUSIONS: The presentation of mild encephalitis/encephalopathy with a reversible splenial lesion is often nonspecific, with behavioral symptoms ranging from irritability to disturbances in consciousness. Its prevalence is higher in the pediatric population, and is thought to be more of an infection-associated encephalopathy syndrome in this group. The infections are typically viral, more so than bacterial. M. pneumoniae, a small, atypical bacterium lacking a peptidoglycan cell wall, is a common respiratory tract pathogen found in children. Despite infection being so rampant in the pediatric community, very few cases of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States have been reported. In Eastern and Southern Asian countries, however, M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion is much more commonly reported. This difference may potentially lie in the prevalence of macrolide-resistant M. pneumoniae, which is significantly higher in Asian countries given more liberal antibiotic use in M. pneumoniae infections. Infections with macrolide-resistant M. pneumoniae are reportedly greater in severity and duration. This amplified state may suggest a correlation between intensity of inflammatory response and the development of mild encephalitis/encephalopathy with a reversible splenial lesion. Given the rarity of M. pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion in the United States, much remains unknown regarding predilection and optimum treatment strategy. As rates of macrolide-resistant M. pneumoniae begin to rise in the United States, maintaining a high level of suspicion remains key in better understanding this unique phenomenon

Drug resistance in Plasmodium falciparum from the Chittagong Hill Tracts, Bangladesh.

OBJECTIVE: To assess the efficacy of antimalarial treatment and molecular markers of Plasmodium falciparum resistance in the Chittagong Hill Tracts of Bangladesh. METHODS: A total of 203 patients infected with P. falciparum were treated with quinine 3 days plus sulphadoxine/pyrimethamine (SP) combination therapy, and followed up during a 4-week period. Blood samples collected before treatment were genotyped for parasite mutations related to chloroquine (pfcrt and pfmdr1 genes) or SP resistance (dhfr and dhps). RESULTS: Of 186 patients who completed follow-up, 32 patients (17.2%) failed to clear parasitaemia or became positive again within 28 days after treatment. Recurring parasitaemia was related to age (chi(2) = 4.8, P < 0.05) and parasite rates on admission (t = 3.1, P < 0.01). PCR analysis showed that some of these cases were novel infections. The adjusted recrudescence rate was 12.9% (95% CI 8.1-17.7) overall, and 16.6% (95% CI 3.5-29.7), 15.5% (95% CI 8.3-22.7) and 6.9% (95% CI 0.4-13.4) in three age groups (<5 years, 5-14, > or =15). The majority of infections carried mutations associated with chloroquine resistance: 94% at pfcrt and 70% at pfmdr. Sp-resistant genotypes were also frequent: 99% and 73% of parasites carried two or more mutations at dhfr and dhps, respectively. The frequency of alleles at dhfr, dhps and pfmdr was similar in cases that were successfully treated and those that recrudesced. CONCLUSIONS: The clinical trial showed that quinine 3-days combined to SP is still relatively effective in the Chittagong Hill Tracts. However, if this regimen is continued to be widely used, further development of SP resistance and reduced quinine sensitivity are to be expected. The genotyping results suggest that neither chloroquine nor SP can be considered a reliable treatment for P. falciparum malaria any longer in this area of Bangladesh

Role of Mothers\u27 Nutritional Knowledge, Nutritional Factors on the School Performance

A cross sectional study was carried out to investigate the effects of mothers\u27 nutritional knowledge, health and nutritional factors and socio-economic parameters on school performance among class five students of University Laboratory School, Dhaka. All of the eighty students were selected for this study. This study found there is a strong relationship between mother\u27s knowledge score and school performance. It was found that mothers\u27 knowledge score was responsible for 91.1 percent change in school performance. The mean BMI of the mothers was 20.44. We found that the school performance measured by class roll number of the students is significantly related with mothers BMI. There was an imperfect negative association between socio-economic parameters and school performance. But the relationship between the school performances with socio-economic parameters was strongly significant. This study also observed the relationship between Individual Dietary Diversity Score (IDDS) of respondent and marks achieved in class 4 final exam. It is alarming that consumption percentage were low for eggs (30) and milk and milk products (37.5), but majority of the students who consumed milk and milk products (63.3%) and eggs (66.7%) got the highest marks

Prevalence and risk factors of gestational diabetes mellitus in Bangladesh: Findings from demographic health survey 2017–2018

Gestational diabetes mellitus (GDM) has serious consequences for both maternal and neonatal health. The growing number of noncommunicable diseases and related risk factors as well as the introduction of new World Health Organization (WHO) diagnostic criteria for GDM are likely to impact the GDM prevalence in Bangladesh. Our study aimed to assess the national prevalence and identify the risk factors using the most recent WHO criteria. We used the secondary data of 272 pregnant women (weighted for sampling strategy) from the Bangladesh Demographic and Health Survey 2017–2018. Multivariate logistic regression was performed to determine the risk factors of GDM. The overall prevalence of GDM in Bangladesh was 35% (95/272). Increased odds of GDM were observed among women living in the urban areas (adjusted odds ratio (aOR) 2.74, 95% confidence interval (CI) 1.43–5.27) compared to rural areas and those aged ≥25 years (aOR 2.03, 95% CI 1.13–3.65). GDM rates were less prevalent in the later weeks of pregnancy compared to early weeks. Our study demonstrates that the national prevalence of GDM in Bangladesh is very high, which warrants immediate attention of policy makers, health practitioners, public health researchers, and the community. Context-specific and properly tailored interventions are needed for the prevention and early diagnosis of GDM

Atypical Idiopathic Intracranial Hypertension Presenting as Cyclic Vomiting Syndrome: A Case Report

BACKGROUND: Idiopathic intracranial hypertension is a disorder of increased intracranial pressure in the absence of cerebrospinal outflow obstruction, mass lesion, or other underlying cause. It is a rare phenomenon in prepubertal children and is most typically found in women of childbearing age. The classic presentation consists of headaches, nausea, vomiting, and visual changes; however, children present more atypically. We report a case of idiopathic intracranial hypertension in an otherwise healthy, 4-year-old child with atypical symptoms resembling those of cyclic vomiting syndrome. CASE PRESENTATION: A 4-year-old Caucasian, otherwise healthy, male child presented to our emergency department with episodic intermittent early-morning vomiting occurring once every 1-3 weeks without interepisodic symptoms, starting 10 months prior. With outpatient metabolic, autoimmune, endocrine, allergy, and gastroenterology work-up all unremarkable, he was initially diagnosed with cyclic vomiting syndrome. Discovery of mild optic nerve sheath distension on magnetic resonance imaging of the brain 10 months after symptom onset led to inpatient admission and a lumbar puncture notable for an opening pressure of 47 mmHg, with normal cell count and protein levels. He had no changes in visual acuity or optic disc edema on dilated fundoscopic examination. The patient was started on acetazolamide, with resolution of episodic emesis at his last follow-up visit 12 weeks after discharge. CONCLUSIONS: Idiopathic intracranial hypertension presents atypically in prepubescent children, with about one-fourth presenting asymptomatically, and only 13-52% presenting with classic symptoms. With a prevalence of only 0.6-0.7 per 100,000, much remains unknown regarding the underlying pathophysiology in this demographic. Cyclic vomiting syndrome, however, has a much higher prevalence in this age group, with a prevalence of 0.4-1.9 per 100. It is thought to be an idiopathic, periodic disorder of childhood, often linked to neurological conditions such as abdominal migraines, epilepsy, mitochondrial disorders, and structural lesions such as chiari malformation and posterior fossa tumors. While cyclic vomiting syndrome is thought to have a benign course, untreated idiopathic intracranial hypertension can have long-term detrimental effects, such as visual loss or even blindness. We present a case of idiopathic intracranial hypertension presenting with symptoms resembling cyclic vomiting syndrome in a 4-year-old child, diagnosed 10 months after initial onset of symptoms. We aim to demonstrate the need for a high level of clinical suspicion and the need for further investigation into underlying pathophysiology in this vulnerable population

Multivariate classification with random forests for gravitational wave searches of black hole binary coalescence

Searches for gravitational waves produced by coalescing black hole binaries with total masses ≳25  M_⊙ use matched filtering with templates of short duration. Non-Gaussian noise bursts in gravitational wave detector data can mimic short signals and limit the sensitivity of these searches. Previous searches have relied on empirically designed statistics incorporating signal-to-noise ratio and signal-based vetoes to separate gravitational wave candidates from noise candidates. We report on sensitivity improvements achieved using a multivariate candidate ranking statistic derived from a supervised machine learning algorithm. We apply the random forest of bagged decision trees technique to two separate searches in the high mass (≳25  M_⊙) parameter space. For a search which is sensitive to gravitational waves from the inspiral, merger, and ringdown of binary black holes with total mass between 25  M_⊙ and 100  M_⊙, we find sensitive volume improvements as high as 70_(±13)%–109_(±11)% when compared to the previously used ranking statistic. For a ringdown-only search which is sensitive to gravitational waves from the resultant perturbed intermediate mass black hole with mass roughly between 10  M_⊙ and 600  M_⊙, we find sensitive volume improvements as high as 61_(±4)%–241_(±12)% when compared to the previously used ranking statistic. We also report how sensitivity improvements can differ depending on mass regime, mass ratio, and available data quality information. Finally, we describe the techniques used to tune and train the random forest classifier that can be generalized to its use in other searches for gravitational waves

Natural organic matter in sedimentary basins and its relation to arsenic in anoxic ground water: the example of West Bengal and its worldwide implications

In order to investigate the mechanism of As release to anoxic ground water in alluvial aquifers, the authors sampled ground waters from 3 piezometer nests, 79 shallow (80 m) wells, in an area 750 m by 450 m, just north of Barasat, near Kolkata (Calcutta), in southern West Bengal. High concentrations of As (200-1180 mug L-1) are accompanied by high concentrations of Fe (3-13.7 mgL(-1)) and PO4 (1-6.5 mg L-1). Ground water that is rich in Mn (1-5.3 mg L-1) contains <50 mug L-1 of As. The composition of shallow ground water varies at the 100-m scale laterally and the metre-scale vertically, with vertical gradients in As concentration reaching 200 mug L-1 m(-1). The As is supplied by reductive dissolution of FeOOH and release of the sorbed As to solution. The process is driven by natural organic matter in peaty strata both within the aquifer sands and in the overlying confining unit. In well waters, thermotolerant coliforms, a proxy for faecal contamination, are not present in high numbers (<10 cfu/100 ml in 85% of wells) showing that faecally-derived organic matter does not enter the aquifer, does not drive reduction of FeOOH, and so does not release As to ground water.Arsenic concentrations are high (much greater than50 mug L-1) where reduction of FeOOH is complete and its entire load of sorbed As is released to solution, at which point the aquifer sediments become grey in colour as FeOOH vanishes. Where reduction is incomplete, the sediments are brown in colour and resorption of As to residual FeOOH keeps As concentrations below 10 mug L-1 in the presence of dissolved Fe. Sorbed As released by reduction of Mn oxides does not increase As in ground water because the As resorbs to FeOOH. High concentrations of As are common in alluvial aquifers of the Bengal Basin arise because Himalayan erosion supplies immature sediments, with low surface-loadings of FeOOH on mineral grains, to a depositional environment that is rich in organic mater so that complete reduction of FeOOH is common. (C) 2004 Published by Elsevier Ltd