Machine Learning in VEP-based BCI

Antud töös esitatakse visuaalse stiimuliga esilekutsutud potentsiaalidel põhineva ajuarvuti liidese (AAL) jaoks klassifitseerimisreegel, mis põhineb tunnuste ja lävendväärtuste omavahelisel võrdlusel. Klassifitseerimise jaoks optimaalsete lävendväärtuste leidmine formaliseeritakse maksimeerimisülesandena, kus maksimeeritakse AALi informatsiooniedastamise kiirus, mille arvutamiseks tuletatakse eraldi valem, et vältida standardse valemi poolt vajalikke eeldusi. Esitatud reegel näitab AALi klassifitseerimisülesandes häid tulemusi, saavutades informatsiooni edastamise kiiruseks kuni 60 bitti minutis. Samuti võimaldab pakutud reegel vältida vale-ennustusi, mis on oluline AALi kasutamiseks igapäevaelus. AALid omavad suurt potentsiaali medistsiini valdkonnas, kuna võimaldavad raske puudega või halvatud isikutel seadmeid kontrollida.In this thesis, a classification method for SSVEP-based BCI is proposed. The classification method is based on simple comparisons of extracted feature values and thresholds and it involves a way of optimising the thresholds. Optimising the thresholds is formalised as a maximisation task of the information transfer rate of BCI, but instead of using the standard formula for calculating ITR, more general formula is derived. This allows the thresholds to be automatically optimised and avoids calculating incorrect ITR estimate.The proposed method shows good performance in classifying targets of a BCI and achieves ITR as high as 60 bit/min. The proposed method also provides a way to reduce false classifications, which is important in real-world applications. BCIs have high potential to be used in the field of medicine as they provides a way for severely disabled people to control external devices

EXAMINATION OF NON-INPATIENT NURSES ABILITY TO ENGAGE IN PATIENT COUNSELING RELATED TO PHYSICAL ACTIVITY AS A HEALTH BEHAVIOR

Physical activity is suggested in the prevention and treatment of chronic disease. Current guidelines recommend at least 150 minutes of physical activity per week. Registered nurses in the non-inpatient setting may have the opportunity to provide patient counseling about physical activity. PURPOSE: The purpose of this study was to examine the counseling behaviors of non-hospital based registered nurses (RN’s) related to physical activity counseling. This study examined the influence of level of nurse training, years of experience, and personal physical activity behaviors on these outcomes. METHODS: Nurses from a state board of nursing and from an academic medical center (N=117) were surveyed regarding counseling behaviors, barriers to counseling, knowledge, ranking of health risk priorities and confidence with physical activity counseling. RESULTS: Of five health risk counseling behaviors queried, 80.9% of nurses reported discussing with patients the intent to adopt a new health behavior; 75.4% of nurses reported advising patients to set goals for health. Respondents reportedly counsel 40% of patients on physical activity for 6.36 (±8.9) minutes per patient and the majority of nurses (68%) reported they agree or strongly agree they are confident counseling about physical activity. Nearly 60% correctly reported current guidelines as 150 minutes or more of physical activity per week. Of 10 health risk behaviors counseled by nurses, physical activity ranked 3rd highest of 10. The most frequently reported barrier to physical activity counseling was “patient not receptive”, reported by 47% of respondents. Further investigation of influence of level of nurse training, years of experience and personal physical activity behaviors on counseling behaviors of nurses is necessary. The results of this study should be interpreted with caution. The smaller than projected sample size, the low response rate and the selected groups of nurses may reduce the generalizability of these findings. CONCLUSION: Non-hospital based nurses are counseling patients regarding physical activity. The majority of nurses reported they are confident with physical activity counseling. Further investigation should expand the group of nurses and should recruit with intent of adequately representing targeted aims. Additionally, the role of training, years of experience and personal behavior should be emphasized

Control a Robot via VEP Using Emotiv EPOC

Antud töö kirjeldab visuaalse stiimuliga esilekutsutud potentsiaalidel põhinevat aju ning arvuti vahelist liidest (AAL), mis loodi antud töö praktilise osana. AALi saab kasutada aju ja seadme vahelise otsese suhtluskanali loomiseks, mis tähendab, et seadmega suhtlemiseks pole vaja nuppe vajutada, piisab vaid visuaalsete stiimulite vaatamisest. Efektiivne AAL võimaldaks raske puudega isikutel näiteks elektroonilist ratastooli juhtida. Antud töö osana loodud AAL kasutab tuntud kanoonilise korrelatsiooni- ja võimsusspektri analüüsi meetodeid ning uuendusena kombineerib need kaks meetodit üheks teineteist täiendavaks meetodiks. Kahe meetodi kombinatsioon muudab AALi täpsemaks. AALi testiti antud töös vaid pealiskaudselt ning tulemused on järgnevad: ühe käsu edastamise aeg 2,61 s, täpsus 85,81% ning informatsiooni edastamise kiirus 27,73 bitt/min. Antud AAL on avatud lähtekoodiga, kirjutatud Python 2.7 programmeerimiskeeles, sisaldab graafilist kasutajaliidest ning kasutab aju tegevuse mõõtmiseks elektroensefalograafia (EEG) seadet Emotiv EPOC. AALi kasutamiseks on vaja ainult arvutit ja Emotiv EPOC seadet. Koodi muutes on võimalik kasutada ka teisi EEG seadmeid.This thesis describes an SSVEP-based BCI implemented as a practical part of this work. One possible usage of a BCI that efficiently implements a communication channel between the brain and an external device would be to help severely disabled people to control devices that currently require pushing buttons, for example an electric wheelchair. The BCI implemented as a part of this thesis uses widely known PSDA and CCA feature extraction methods and introduces a new way to combine these methods. Combining different methods improves the performance of a BCI. The application was tested only superficially and the following results were obtained: 2.61 s target detection time, 85.81% accuracy and 27.73 bits/min ITR. The implemented BCI is open-source, written in Python 2.7, has graphical user interface and uses inexpensive EEG device called Emotiv EPOC. The BCI requires only a computer and Emotiv EPOC, no additional hardware is needed. Different EEG devices could be used after modifying the code

Characterization of Xylella fastidiosa Virulence Factors and Host Physiological Responses That Contribute to Pierce's Disease in Grapevine

Xylella fastidiosa is a xylem-limited bacterium that causes Pierce’s Disease (PD) in grapevine. PD symptom progression is correlated with systemic colonization by X. fastidiosa, which occurs via pit membrane degradation. Previous studies determined that a polygalacturonase, one of several cell wall degrading enzymes (CWDEs) secreted by X. fastidiosa, is necessary for pit membrane degradation. Here, it is demonstrated that the loss of two X. fastidiosa β-1,4-endoglucanases (EGases) in tandem causes significantly slower PD symptom development and progression, and reduces X. fastidiosa virulence and population size. Furthermore, differences in the PD symptom progression rate between two cultivars appear to be caused by variations in pit membrane carbohydrate composition, which influence the rate of enzymatic degradation, and subsequently, the rate of systemic colonization. How these CWDEs and other virulence factors are secreted has not been fully elucidated. However, several are predicted to be secreted via the Type II secretion system (T2SS). T2SS-deficient X. fastidiosa mutants did not induce PD symptoms, and the mutant bacteria were not recovered from infected vines, indicating that the T2SS and its secreted substrates are necessary for virulence and survival. Analysis of wild type X. fastidiosa and T2SS-deficient mutant secretomes found six potential Type II secreted proteins for further characterization, including three lipases, a β-1,4-cellobiohydrolase, a protease, and a hypothetical protein. However, none of the CWDEs were present in the secretomes, but their high transcript abundance indicates that these enzymes could be post-transcriptionally regulated. Several PD symptoms appear similar to drought stress symptoms. Under drought conditions, decreased photosynthesis, cessation of plant growth, and carbon starvation occur. Tylose formation in response to X. fastidiosa infection occludes vessels to prevent the spread of pathogens and air embolisms. Interestingly, genes involved in photosynthesis and plant growth are down-regulated during PD symptom development, and tylose formation increases significantly. This increased vessel occlusion in the absence of new vessel formation over time could cause prolonged water stress. Furthermore, starch in the ray parenchyma depletes as PD symptoms progress, indicating that carbon starvation occurs. These results indicate that, along with X. fastidiosa-mediated virulence factors, host responses also contribute to PD

Searching Turing instabilities in the Abrams-Strogatz model

The aim of this thesis is to search for Turing instabilities in Abrams-Strogatz language competition model. The theoretical part of this thesis provides an overview of complex systems, explains the nature of Turing patterns and the conditions for pattern formation, describes the aspects of language dynamics and Abrams-Strogatz model. In the practical part of the thesis, the original Abrams-Strogatz model is extended with spatial parameter and using stability analysis Turing instabilities are investigated in the spatial model

Valitsemisega seotud institutsionaalsete tegurite mõju korruptsiooni tajumisele

Käesolevas töös oli käsitlemisel eelkõige erasektoriga seonduv korruptsioonitemaatika. Eesmärgiks oli selgitada välja potentsiaalsed seosed korruptsioonitaju kui korruptsiooni olemasolu tunnistamise ja selle kujunemist mõjutavate institutsionaalsete tegurite – regulatiivse kvaliteedi, valitsuse efektiivsuse ning õigusnorme puudutavate näitajate vahel. Tegemist on aktuaalse probleemiga, kuna ükski ühiskond pole korruptsioonile immuunne, samuti kaasneb korruptsiooniga näiteks välisinvesteeringute vähenemine, majanduskasvu pidurdumine, ettevõtte maine langus ja palju muud. Korruptsioonitaseme muutumise uurimine sõltuvalt erinevatest aspektidest on eriti oluline rahvusvahelisel tasandil partnereid valides. Korruptsiooni mõjutajatena on läbi aegade nähtud mitmeid erinevaid tegureid, näiteks on selles suureks vormijaiks peetud kultuuri, ent ka poliitilist, majanduslikku ja õigussüsteemi. Seosed riigi valitsemise „headuse“ ja korruptsiooni kontrollimise ning selle tajumise vahel ei ole siiani olnud üksüheselt mõistetavad. Antud bakalaureusetöös tugineti eeldusele, et tõhusamad aruandekohustuse mehhanismid vähendavad korruptsiooni levimist, efektiivsemad valitsused loovad parema regulatiivse keskkonna, ning et õigusriiklus aitab vähendada ametikoha ärakasutamist. Antud eeldust testiti mitmemõõtmelise regressioonanalüüsi abil. Esmalt asuti välja selgitama seoste olemasolu korruptsioonitaju ning seda mõjutavate tegurite vahel. Hajusdiagrammide põhjal võis oletada, et tunnuste vahel on seos – punktid moodustasid väljavenitatud parve, seos oli kasvav ning tugev. Objektiivsema hinnangu saamiseks võeti kasutusele arvulised hinnangud, mis mõõdaksid tunnustevaheliste seoste tugevust. Selle tulemusena selgus, et valitsuse efektiivsuse ja õigusriikluse puhul olid seosed suuremad kui regulatiivse kvaliteedi puhul. Samuti ilmnes, et kui valitsemise efektiivsuse ja õigusriikluse puhul pidasid püstitatud hüpoteesid paika – kõrgema korruptsioonitaseme ning eelnimetatud tegurite vahel oli tõepoolest olemas tugev negatiivne seos, siis regulatiivse kvaliteedi puhul oli tegemist vastupidisega – korruptsiooni vähesemal määral kontrollimise ning regulatiivse kvaliteedi vahel oli positiivne seos. Siiski selgus regressioonanalüüsi abil seoseid kontrollides, et teguri väikese väärtuse tõttu see kadus. Ainuüksi regulatiivsest kvaliteedist korruptsioonitaju muutumiseks ei piisa, ent õigusriiklus ja valitsuse efektiivsus võivad korruptsioonitasemele mõju avaldada ka eraldiseisvalt. Korruptsiooni uurimine on eelkõige selle peidetud iseloomu tõttu keeruline. Lisaks sellele, et andmeid on keeruline koguda, on ka saadud andmed sageli subjektiivsed, seda nii kultuurist, ent ka sotsiaalsetest ja psühholoogilistest põhjustest tingituna. Maailmapanga World Governance Indicatorit tasub pigem siiski vaadelda kui täiendavat allikat teabe kogumisel, konkreetsete poliitiliste meetmete välja töötamisel tasub saadud andmeid kõrvutada ka mitmete teiste allikatega, et saada korruptsioonist ning valitsemisest põhjalikum ülevaade.http://www.ester.ee/record=b4580934*es

Tensile Testing Environmental Chamber – Structural

Environmental chambers for tensile testing machines are used to study how a multitude of materials behave in extreme temperatures. These chambers provide the necessary information to innovate cutting edge technology for materials in fields such as aerospace. These chambers are often heavy and expensive requiring a significant amount of time and money just in the installation process alone. This report will serve to outline and define the design and fabrication of an environmental chamber, conducted by a team of four senior mechanical engineering students at California Polytechnic State University, San Luis Obispo. The goals of the project include a low-weight product, accurate and precise temperature changes within the chamber, visibility of the testing area, and ease of installation of the product on the tensile testing machine. This document provides an in-depth definition of the problem and a description of the background research conducted and presents the team’s initial design ideas as well as the concep

Resources and predation: drivers of sociality in a cyclic mesopredator

In socially fexible species, the tendency to live in groups is expected to vary through a trade-of between costs and benefts, determined by ecological conditions. The Resource Dispersion Hypothesis predicts that group size changes in response to patterns in resource availability. An additional dimension is described in Hersteinsson’s model positing that sociality is further afected by a cost–beneft trade-of related to predation pressure. In the arctic fox (Vulpes lagopus), group-living follows a regional trade-of in resources’ availability and intra-guild predation pressure. However, the efect of local fuctuations is poorly known, but ofers an unusual opportunity to test predictions that difer between the two hypotheses in systems where prey availability is linked to intra-guild predation. Based on 17-year monitoring of arctic fox and cyclic rodent prey populations, we addressed the Resource Dispersion Hypothesis and discuss the results in relation to the impact of predation in Hersteinsson’s model. Group-living increased with prey density, from 7.7% (low density) to 28% (high density). However, it remained high (44%) despite a rodent crash and this could be explained by increased benefts from cooperative defence against prey switching by top predators. We conclude that both resource abundance and predation pressure are factors underpinning the formation of social groups in fuctuating ecosystems.publishedVersio