136 research outputs found

    Issues of Architectural Description Languages for Handling Dynamic Reconfiguration

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    Dynamic reconfiguration is the action of modifying a software system at runtime. Several works have been using architectural specification as the basis for dynamic reconfiguration. Indeed ADLs (architecture description languages) let architects describe the elements that could be reconfigured as well as the set of constraints to which the system must conform during reconfiguration. In this work, we investigate the ADL literature in order to illustrate how reconfiguration is supported in four well-known ADLs: pi-ADL, ACME, C2SADL and Dynamic Wright. From this review, we conclude that none of these ADLs: (i) addresses the issue of consistently reconfiguring both instances and types; (ii) takes into account the behaviour of architectural elements during reconfiguration; and (iii) provides support for assessing reconfiguration, e.g., verifying the transition against properties.Comment: 6\`eme Conf\'erence francophone sur les architectures logicielles (CAL'2012), Montpellier : France (2012

    Delay and Cooperation in Nonstochastic Bandits

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    We study networks of communicating learning agents that cooperate to solve a common nonstochastic bandit problem. Agents use an underlying communication network to get messages about actions selected by other agents, and drop messages that took more than dd hops to arrive, where dd is a delay parameter. We introduce \textsc{Exp3-Coop}, a cooperative version of the {\sc Exp3} algorithm and prove that with KK actions and NN agents the average per-agent regret after TT rounds is at most of order (d+1+KNα≀d)(Tln⁥K)\sqrt{\bigl(d+1 + \tfrac{K}{N}\alpha_{\le d}\bigr)(T\ln K)}, where α≀d\alpha_{\le d} is the independence number of the dd-th power of the connected communication graph GG. We then show that for any connected graph, for d=Kd=\sqrt{K} the regret bound is K1/4TK^{1/4}\sqrt{T}, strictly better than the minimax regret KT\sqrt{KT} for noncooperating agents. More informed choices of dd lead to bounds which are arbitrarily close to the full information minimax regret Tln⁥K\sqrt{T\ln K} when GG is dense. When GG has sparse components, we show that a variant of \textsc{Exp3-Coop}, allowing agents to choose their parameters according to their centrality in GG, strictly improves the regret. Finally, as a by-product of our analysis, we provide the first characterization of the minimax regret for bandit learning with delay.Comment: 30 page

    Applicazione di tecniche remote sensing per lo studio dell'evoluzione e della dinamica criosferica in aree remote e di alta quota

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    I ghiacciai sono efficaci indicatori climatici poich\ue8 si modificano in risposta ai cambi del clima (es. temperatura e precipitazioni). L'attenzione sui ghiacciai di montagna sta aumentando tra la comunit\ue0 scientifica per via del loro sempre pi\uf9 evidente arretramento a scala globale negli ultimi cinquant'anni. Ci\uf2 \ue8 conseguenza del riscaldamento globale. Comprendere il comportamento dei ghiacciai in risposta al cambio climatico \ue8 di enorme importanza non solo per arricchire la conoscenza scientifica, ma anche per poter meglio gestire in futuro le situazioni di rischio naturale che possono colpire le popolazioni che vivono nelle zone montuose, sia nel breve termine (es. GLOF), sia nel lungo (es. Siccit\ue0). Questa tesi di dottorato analizza differenti aspetti della criosfera (ghiacciai e neve) per descriverne la variabilit\ue0 recente e le relazioni con la dinamica climatica. Inizialmente ci si \ue8 concentrati sul Karakorum. Questa \ue8 un\u2019area particolare per gli studi criosferici, che non segue i trend globali di regresso; infatti, in questa zona il bilancio di massa netto dei ghiacciai nei primi anni del ventunesimo secolo \ue8 stato leggermente positivo, con anche taluni casi di espansione. Questa eccezionale situazione \ue8 riconosciuta con il nome di Anomalia del Karakorum (Karakoram Anomaly). Pi\uf9 precisamente il presente elaborato si focalizza sulla zona del Central Karakoram National Park (CKNP), un'area protetta nel nord del Pakistan, rappresentativa della glaciazione dell'intera catena del Karakorum. In questa regione, i venti occidentali rappresentano il sistema di venti dominante e sono presenti nella stagione invernale, mentre la confinante regione Himalayana \ue8 sotto l'influenza predominante dei monsoni, che sono venti estivi. Il presente lavoro descrive in maniera completa lo stato dei ghiacciai del CKNP e la loro recente evoluzione. Ci\uf2 \ue8 stato possibile a seguito della compilazione del catasto glaciale del parco per gli anni 2001 e 2010, a sua volta descritto nel dettaglio nel presente elaborato. Inoltre \ue8 discussa l'analisi dei cambiamenti climatici poi messa in relazione con quelli glaciali, per poter comprendere le cause dietro l'Anomalia del Karakorum. Il cambiamento areale dei 711 ghiacciai mappati nell'area di studio \ue8 stato -0.4 \ub1 202.9 km2 (su 4605.9 \ub1 86.1 km2 nel 2001), il che evidenzia una generale situazione di stabilit\ue0. Anche l'analisi climatica supporta tale condizione di stabilit\ue0. Durante il periodo 2001\u20132010 si \ue8 osservato grazie ai dati del sensore MODIS un leggero aumento delle aree coperte da neve a fine estate. Allo stesso tempo, dati meteo dalle stazioni disponibili hanno rivelato un aumento delle nevicate e una diminuzione della temperatura media dell'aria in estate fin dal 1980, il che si tradurrebbe in coperture nivali pi\uf9 persistenti durante la stagione ablativa. Questi risultati vanno a favore della preservazione glaciale nelle zone di ablazione dovuta a una copertura di neve pi\uf9 duratura, e un maggiore accumulo a quote pi\uf9 alte, presupponendo bilanci di massa netti tendenti al segno positivo. L'altro principale obiettivo del presente elaborato di tesi \ue8 quello di fornire un modello di semplice utilizzo per quantificare l'ablazione di ghiaccio alla superficie glaciale. Dal momento che una copertura detritica sopraglaciale \ue8 in grado di alterare la fusione del ghiaccio vicino alla superficie in funzione dello spessore, il modello tiene conto di due diversi casi: una parte stima l'ablazione per le aree di ghiaccio scoperto con un metodo definito enhanced T-index; l'altra stima la fusione per le zone coperte da detrito, utilizzando un modello di flusso di calore conduttivo. Per quanto concerne le parti coperte da detrito, \ue8 stata prodotta una mappa degli spessori detritici che \ue8 poi stata usata come input per il modello, assieme alla radiazione solare entrante distribuita. Per le aree scoperte da detrito, sono state derivate la temperatura dell'aria e la radiazione entrante distribuite attraverso i dati delle stazioni meteo automatiche presenti nell'area, in seguito usate come input. L'altro parametro necessario \ue8 un modello di elevazione del terreno. In particolare, la distribuzione degli input meteorologici \ue8 stata validata con dati di altre due stazioni presenti all'interno del CKNP (le stazioni di Urdukas e Concordia). L'ablazione modellata \ue8 risultata essere fortemente concorde con le misurazioni effettuate sul ghiacciaio del Baltoro nel 2011, ghiacciaio rappresentativo di tutto il CKNP. Due campioni dello stesso set di dati di fusione misurati su terreno sono stati usati ciascuno rispettivamente in sede di calibrazione e validazione. La fusione nivale \ue8 stata ignorata dal momento che mancavano dati di neve sistematici nell'area di studio. Il modello \ue8 stato fatto girare durante il picco della stagione ablativa (23 luglio\u20139 agosto 2011), durante il quale l'acqua di fusione deriva primariamente dalla fusione glaciale, mentre quella nivale ha un ruolo decisamente minore in questa regione. Il modello ha calcolato un totale di acqua da fusione glaciale pari a 1.963 km3 (0.109 km3 al giorno in media). Quella derivante dalle parti coperte da detrito ammonta a 0.223 km3 (0.012 km3 al giorno in media; min\u2013max 0.006\u20130.016 km3 al giorno), mentre per le parti a ghiaccio scoperto \ue8 1.740 km3 (0.097 km3 al giorno in media; min\u2013max 0.041\u20130.139 km3 al giorno). Tale quantit\ue0 \ue8 paragonabile al 14% di tutta l'acqua contenuta in una grande diga strategica lungo il fiume Indo, di cui i ghiacciai del CKNP sono tributari. I test di sensitivit\ue0 del modello suggeriscono che un aumento delle superfici coperte da detrito sui ghiacciai (probabile per via dell'aumento di eventi di macrogelivazione e di frane) avr\ue0 un notevole impatto sulla fusione effettiva in funzione dei nuovi spessori detritici, e l'ablazione aumenter\ue0 sensibilmente se la temperatura dell'aria dovesse alzarsi. Successivamente l'attenzione del presente elaborato di tesi \ue8 concentrata sulle Ande Cilene e sulla variabilit\ue0 della copertura nevosa. Un obiettivo principale parallelo della presente ricerca \ue8 stato infatti quello di individuare una metodologia basata sul telerilevamento per studiare la variazione della copertura nevosa ad una risoluzione spazio-temporale accettabile. Il sensore MODIS si \ue8 rivelato il pi\uf9 idoneo allo scopo ed \ue8 stata implementata una metodologia che permettesse di estrarre mappe di copertura di neve in maniera automatica dalle informazioni raccolte dal sensore stesso. In particolare, sono stati studiati diciotto bacini idrografici di montagna delle Ande centrali in Cile durante il periodo 2008\u20132011. La stessa metodologia \ue8 stata esportata e adottata per l'analisi della neve nel CKNP come detto. L'area di studio \ue8 stata divisa in tre sotto-zone (Settentrionale, Centrale, Meridionale), per alleggerire il carico di calcolo dell'analisi. In generale, l'area coperta da neve \ue8 diminuita nel corso dei quattro anni di riferimento. I valori massimi sono stati ritrovati nella zona centrale, mentre fattori topografici e climatici (i.e. quote basse pi\uf9 a sud e un clima pi\uf9 arido nel nord), hanno limitato la deposizione della neve nelle altre zone. La linea della neve \ue8 pi\uf9 alta nella zona settentrionale a causa della presenza dell'altopiano, e si abbassa via via verso la zona merdionale. Nella zona settentrionale i minimi di copertura nivale vengono raggiunti prima che nelle altre zone e durano pi\uf9 a lungo (da novembre a marzo), probabilmente a causa del clima pi\uf9 arido. Durante l'intero periodo i valori massimi di copertura nevosa si ritrovano verso ovest. Al termine dell'elaborato e pertinente al tema principale delle applicazioni del telerilevamento allo studio della criosfera, sono presentati alcuni esempi di analisi di ghiacciai di diversa tipologia, dimensione e area geografica. Si tratta di sei casi, fra cui sono presenti tre ghiacciai alpini (Miage, Freney, Aletcsh), ghiacciai equatoriali (i ghiaccia del Kilimajaro), l'Harding Icefield in Alaska e un esempio di ghiacciaio antartico (la Drygalsky ice Tongue).Glaciers are sensitive climate indicators because they adjust their size in response to changes in climate (e.g. temperature and precipitation). The attention paid by the scientists to mountain glacier change is increasing as there are robust evidence of a global glacier shrinkage over the past five decades, which in turn is the consequence of global warming. Understanding the glacier response to climate change is of tremendous importance not only for improving scientific knowledge, but also to predict and manage water resources and natural risks for the people living in mountain areas in the short (e.g. glacier lake outburst floods), and long term (e.g. droughts). In this thesis are analysed different cryospheric elements (mainly glaciers and snow coverage) to describe their recent evolution and to look for relations, if any, with climate trends. Firstly, the focus is put on the Karakoram glaciers. Although a general worldwide retreat of mountain glaciers has been acknowledged by the scientific community, the Karakoram region represents an exception in this sense. Indeed, the net mass balance of the glaciers here in the early twenty-first century was slightly positive, and even some are expanding and thickening. This anomalous behaviour is known as Karakoram Anomaly. More precisely the study area is the Central Karakoram National Park (CKNP), a protected national park in Northern Pakistan representative of the glaciation of the whole Karakoram Range. The westerlies represent the dominant wind system and they occur during winter, while the neighbour Himalayan region is mainly influenced by the summer moonson. A comprehensive description of the state of the CKNP glaciers and of their recent evolution is presented. This was made after the compilation of the glacier inventory of the park for the years 2001 and 2010, which is also presented. Moreover, the analysis of the regional climate change in the recent years is also discussed and related to the actual glacier change, in order to understand the causes behind the Karakoram Anomaly. The glacier area change of the 711 glaciers mapped in the study zone during 2001\u20132010 was only -0.4 \ub1 202.9 km2 (over 4605.9 \ub1 86.1 km2 in 2001), evidencing a general stability. The climate analysis supports glacier stability in the area. A slight increase in late summer snow cover area during 2001\u20132010 was observed from MODIS snow data. At the same time, the available weather stations revealed an increase of snowfall events and a decrease of mean summer air temperatures since 1980, which would translate into more persistent snow cover during the melt season. These results support an enhanced glacier preservation in the ablation areas due to a long-lasting snow cover, and stronger accumulation at higher altitudes, pushing towards positive net balances. The other major aim of the present work is to provide a simple model to evaluate ice melt at the glacier surface. As the supraglacial-debris cover can alter ice ablation close to the glacier surface depending on its thickness, the model was made up of two parts: one which computes the ice melt over the bare ice areas using an enhanced T-index formula; and one for the debris-covered areas using a conductive heat flux module. For the debris-covered parts, the debris thickness map is produced and then provided to the model as input for the computation, other than the distributed shortwave incoming radiation. For the bare ice areas, the modeled air temperature and shortwave incoming radiation are derived from the automatic weather stations present in the CKNP and given to the model. The other model requirement is the digital elevation model. In particular, the meteorological input data were distributed starting from data acquired at Askole automatic weather station, located within the CKNP. The meteorological distribution was validated by comparison with data from other two AWS in the same park limits (Urdukas and Concordia). The modeled ablation data were in strong agreement with measurements collected in the field during 2011 on Baltoro glacier, which is representative of CKNP glaciers. Two sets of the same ablation dataset collected in the field in the CNKP area were used separately for calibration and validation. Snow melt was neglected since snow data in the study area was not systematically available. The model was run against the peak ablation season (23 July\u20139 August 2011), when meltwater mainly comes from ice melt, with snow thaw playing a minor role in this region. The total freshwater from the ablation areas of CKNP glaciers estimated by the model was 1.963 km3 (0.109 km3 d\u20131 on average). The meltwater from the debris-covered parts was 0.223 km3 (0.012 km3 d\u20131 on average; min\u2013max 0.006\u20130.016 km3 d\u20131), and 1.740 km3 (0.097 km3 d\u20131 on average; min\u2013max 0.041\u20130.139 km3 d\u20131) from debris-free sectors. The estimated total freshwater corresponds to 14% of the water contained in a large strategic dam along the Indus River, of which all the CKNP glaciers are tributaries. The sensitivity tests suggest that any increase in the extent of debris coverage (which will likely occur due to augmented macrogelivation processes and rockfall events), will affect melt depending on new debris thickness, and melting will increase largely if summer air temperature increases. The second major focus of this research is put on the snow cover variability of the Chilean Andes. A parallel major aim of this research work is to implement a methodology based on remote sensing to study the snow cover variation on an acceptable spatio-temporal resolution. The MODIS sensor was chosen as the most suitable for this purpose and a methodology for deriving snow maps automatically from it is described and applied for analyzing the SCA variation over 18 watersheds of the central Andes in Chile during 2008\u20132011. The same methodology was then adopted for the climate analysis in the CKNP as mentioned. The study area was divided into three sub-zones (Northern, Central, and Southern), for easing the computation of the snow analysis. Overall, SCA decreased during the four considered years. The maximum SCA was found in the Central Zone, while the topographic and climatic features (i.e. lower altitudes in the South, and a drier climate in the North), limited snow deposition elsewhere. The snow line was found higher in the Northern zone due to the presence of the plateau, while it decreases southwards. In the Northern Zone the minimum SCA was reached sooner than elsewhere, and it lasted for a longer period (November to March), probably because of the drier climate. West aspects showed the maximum of SCA in all zones throughout the study period. Finally, some examples of application of remote sensing to glacier related studies is presented for glaciers of various typology, size, and localization. Six case studies are shown, amongst which there are three alpine glaciers (Miage, Freney, Aletcsh), equatorial glaciers (the Kilimanjaro glaciers), the Harding Icefield in Alaska, and an Antarctic glacier (the Drygalsky Ice Tongue)

    Pengaruh Teknik Relaksasi Nafas Dalam Terhadap Tingkat Kecemasan Pasien Preoperasi Katarak Di Rumah Sakit Khusus Mata Provinsi Sumatera Selatan

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    Anxiety is a term familiar to everyday life depicting the state of worry, touch-and-go restlessness, fear and not feeling tranquil, which is sometimes accompanied by physical complaints. The relaxation technique through deep breathingis the treatment modality or alternative treatment used to reduce the level of anxiety of patients who have undergone cataract surgery. This researchaims to determine the Effects of the Relaxation Technique through Deep Breathing on the Level of Anxiety of the Patients Who Have Undergone Cataract Surgery at the Eye Care Hospital of South Sumatra Province in 2015. This is quantitative research employing the pre-experimental design with the one group pretest-posttest design. The sampling technique used was purposive sampling with a total of 34 respondents who met the inclusion criteria using the DASS or Depression Anxiety Stress Scale questionnaire. The data were analyzed using univariate and bivariate analyzes. The findings suggest that the average level of anxiety of the respondents before the relaxation technique through deep breathingwas performed is 10.47 with a median by 10.00 and after the relaxation technique through deep breathingwas performed, the average level of anxiety of the respondentsis equal to 8.00 with a median by8.00 in which the effects of the relaxation technique through deep breathing on the level of anxiety of the patients have been identified. Such effects were revealed using an independednt t-testin which the test results indicate that the p value is equal to 0.001 or less than α = 0.05. The relaxation technique through deep breathing can be used by nurses to reduce the level of anxiety of the patients who have undergone cataract surgery

    Monitoring COVID-19-induced gender differences in teleworking rates using Mobile Network Data

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    The COVID-19 pandemic has created a sudden need for a wider uptake of home-based telework as means of sustaining the production. Generally, teleworking arrangements impacts directly worker's efficiency and motivation. The direction of this impact, however, depends on the balance between positive effects of teleworking (e.g. increased flexibility and autonomy) and its downsides (e.g. blurring boundaries between private and work life). Moreover, these effects of teleworking can be amplified in case of vulnerable groups of workers, such as women. The first step in understanding the implications of teleworking on women is to have timely information on the extent of teleworking by age and gender. In the absence of timely official statistics, in this paper we propose a method for nowcasting the teleworking trends by age and gender for 20 Italian regions using mobile network operators (MNO) data. The method is developed and validated using MNO data together with the Italian quarterly Labour Force Survey. Our results confirm that the MNO data have the potential to be used as a tool for monitoring gender and age differences in teleworking patterns. This tool becomes even more important today as it could support the adequate gender mainstreaming in the ``Next Generation EU'' recovery plan and help to manage related social impacts of COVID-19 through policymaking.Comment: added figure

    Role of Neuronal Nitric Oxide Synthase on Cardiovascular Functions in Physiological and Pathophysiological States

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    This review describes and summarizes the role of neuronal nitric oxide synthase (nNOS) on the central nervous system, particularly on brain regions such as the ventrolateral medulla (VLM) and the periaqueductal gray matter (PAG), and on blood vessels and the heart that are involved in the regulation and control of the cardiovascular system (CVS). Furthermore, we shall also review the functional aspects of nNOS during several physiological, pathophysiological, and clinical conditions such as exercise, pain, cerebral vascular accidents or stroke and hypertension. For example, during stroke, a cascade of molecular, neurochemical, and cellular changes occur that affect the nervous system as elicited by generation of free radicals and nitric oxide (NO) from vulnerable neurons, peroxide formation, superoxides, apoptosis, and the differential activation of three isoforms of nitric oxide synthases (NOSs), and can exert profound effects on the CVS. Neuronal NOS is one of the three isoforms of NOSs, the others being endothelial (eNOS) and inducible (iNOS) enzymes. Neuronal NOS is a critical homeostatic component of the CVS and plays an important role in regulation of different systems and disease process including nociception. The functional and physiological roles of NO and nNOS are described at the beginning of this review. We also elaborate the structure, gene, domain, and regulation of the nNOS protein. Both inhibitory and excitatory role of nNOS on the sympathetic autonomic nervous system (SANS) and parasympathetic autonomic nervous system (PANS) as mediated via different neurotransmitters/signal transduction processes will be explored, particularly its effects on the CVS. Because the VLM plays a crucial function in cardiovascular homeostatic mechanisms, the neuroanatomy and cardiovascular regulation of the VLM will be discussed in conjunction with the actions of nNOS. Thereafter, we shall discuss the up-to-date developments that are related to the interaction between nNOS and cardiovascular diseases such as hypertension and stroke. Finally, we shall focus on the role of nNOS, particularly within the PAG in cardiovascular regulation and neurotransmission during different types of pain stimulus. Overall, this review focuses on our current understanding of the nNOS protein, and provides further insights on how nNOS modulates, regulates, and controls cardiovascular function during both physiological activity such as exercise, and pathophysiological conditions such as stroke and hypertension

    2008-2011 snow covered area (SCA) variability over 18 watersheds of the central Chile through MODIS data

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    Snowmelt contributes largely to water budget of several Chilean mountain watersheds. To describe snow covered area (SCA) variability within 18 watersheds in Central Chile during 2008\u20132011 we used MODIS data (i.e. MOD10A2-V5 maximum snow cover extent in eight-day periods). The study area was divided into three different zones (Northern, Central, and Southern), due to its large extent (~205,000 km2), and according to former studies performed by the Direcc\uedon General de Aguas (DGA) of the Chilean Government covering the time window 2000\u20132007. After georeferencing our data to the WGS84 Datum (UTM Projection, zone 19S), the scenes were cropped to fit the study area. We selected and set a threshold for cloud coverage (<30%) in order to discard the images with too cloud cover, so losing only 2% of the sample. Hypsographic and aspect analyses were performed using the SRTM3 elevation model. We found largest values of SCA during 2008\u20132011 in the Central Zone, while the topographic and climatic features (i.e. lower altitudes in the South, and a drier climate in the North) limit snow deposition elsewhere. Similarly, snow line is higher in the Northern zone (due to the presence of the plateau), and lower moving southwards. In the North the minimum SCA is reached sooner than elsewhere, lasting for a longer period (November to March). West side showed the maximum of SCA in all zones throughout the study period. The present work extends in time the dataset of SCA in the Central Chile, adding information for statistic assessment, and trend analysis of snow cover in this area

    The development of proton-electron math e-comic to improve special needs students’ mathematical concepts understanding

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    Technology-based learning media is still lacking for special needs students in mathematics. Based on observations and interviews with Special School (SLB) teachers, the learning media used were still monotonous, such as picture books and writing using a blackboard. This research aims to develop e-comic math using the App Pixton application, which is valid and practical for children with special needs in SLB. The research method used is Plomp model development research in the prototype development phase: self-evaluation, expert review, and one-to-one evaluation. The data collection instruments used were a questionnaire and mathematical concepts on addition and subtraction topics for students with special needs. The research subjects were 21 students and 5 teachers from 5 different special schools in 5 West Sumatra, Indonesia cities. The study results show that the media developed is valid and practical for students with deaf and intellectual disabilities. This research implies that teachers must be able to develop other IT-based learning media to help students with special needs learn mathematics like normal children
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