Letteratura scientifica selezionata sul tema "Positive-only data"
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Articoli di riviste sul tema "Positive-only data"
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Qin, Xiangju, Yang Zhang, Chen Li e Xue Li. "Learning from data streams with only positive and unlabeled data". Journal of Intelligent Information Systems 40, n. 3 (5 gennaio 2013): 405–30. http://dx.doi.org/10.1007/s10844-012-0231-6.
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Terada, Yoshikazu, Issei Ogasawara e Ken Nakata. "Classification from only positive and unlabeled functional data". Annals of Applied Statistics 14, n. 4 (dicembre 2020): 1724–42. http://dx.doi.org/10.1214/20-aoas1404.
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Becerra-Bonache, Leonor. "Learning SECp Languages from Only Positive Data". Triangle, n. 8 (29 giugno 2018): 1. http://dx.doi.org/10.17345/triangle8.1-18.
Testo completoAbstract (sommario):
The eld of Grammatical Inference provides a good theoretical framework for investigating a learning process. Formal results in this eld can be relevant to the question of rst language acquisition. However, Grammatical Inference studies have been focused mainly on mathematical aspects, and have not exploited the linguistic relevance of their results. With this paper, we try to enrich Grammatical Inference studies with ideas from Linguistics. We propose a non-classical mechanism that has relevant linguistic and computational properties, and we study its learnability from positive data.
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Daneshpazhouh, Armin, e Ashkan Sami. "Semi-Supervised Outlier Detection with Only Positive and Unlabeled Data Based on Fuzzy Clustering". International Journal on Artificial Intelligence Tools 24, n. 03 (giugno 2015): 1550003. http://dx.doi.org/10.1142/s0218213015500037.
Testo completoAbstract (sommario):
The task of semi-supervised outlier detection is to find the instances that are exceptional from other data, using some labeled examples. In many applications such as fraud detection and intrusion detection, this issue becomes more important. Most existing techniques are unsupervised. On the other hand, semi-supervised approaches use both negative and positive instances to detect outliers. However, in many real world applications, very few positive labeled examples are available. This paper proposes an innovative approach to address this problem. The proposed method works as follows. First, some reliable negative instances are extracted by a kNN-based algorithm. Afterwards, fuzzy clustering using both negative and positive examples is utilized to detect outliers. Experimental results on real data sets demonstrate that the proposed approach outperforms the previous unsupervised state-of-the-art methods in detecting outliers.
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Tomeo, Paolo, Ignacio Fernández-Tobías, Iván Cantador e Tommaso Di Noia. "Addressing the Cold Start with Positive-Only Feedback Through Semantic-Based Recommendations". International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems 25, Suppl. 2 (dicembre 2017): 57–78. http://dx.doi.org/10.1142/s0218488517400116.
Testo completoAbstract (sommario):
Recommender systems aim to provide users with accurate item suggestions in a personalized fashion, but struggle in the case of cold start users, for whom there is a scarcity of preference data. User preferences can be either explicitly stated by the users — often by means of ratings —, or implicitly acquired by a system — for instance by mining text reviews, search queries, and purchase records. Recommendation methods have been mostly designed to deal with numerical ratings. However, real scenarios with user preferences expressed in the form of binary and unary (positive-only) feedback, e.g. the thumbs up/down in YouTube, and the likes in Facebook, are increasingly popular, and make the user cold start problem even more challenging. To address the cold start with positive-only feedback situations, we propose to exploit data additional to user preferences by means of specialized hybrid recommendation methods. In particular, we investigate a number of graph-based and matrix factorization recommendation models that jointly exploit user preferences and item semantic metadata automatically extracted from the well-known knowledge graph of DBpedia. Following a rigorous evaluation methodology for cold start, we empirically compare the above hybrid recommendation models on a Facebook dataset containing users likes for items in three different domains, namely books, movies and music. The achieved experimental results show that the semantics-aware hybrid approaches we propose outperform content-based and collaborative filtering baselines. In addition to recommendation accuracy, in our evaluation we also consider individual and aggregate diversity of recommendations as key quality factors in the users’ satisfaction.
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Leibowitz, Arleen A., e Katherine Desmond. "Do Only 21% of HIV-Positive Medicaid Enrollees Link to Treatment? Challenges in Interpreting Medicaid Claims Data". Sexually Transmitted Diseases 40, n. 7 (luglio 2013): 582. http://dx.doi.org/10.1097/01.olq.0000430802.91969.98.
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Cheng, Zhanzhan, Shuigeng Zhou e Jihong Guan. "Computationally predicting protein-RNA interactions using only positive and unlabeled examples". Journal of Bioinformatics and Computational Biology 13, n. 03 (15 maggio 2015): 1541005. http://dx.doi.org/10.1142/s021972001541005x.
Testo completoAbstract (sommario):
Protein–RNA interactions (PRIs) are considerably important in a wide variety of cellular processes, ranging from transcriptional and post-transcriptional regulations of gene expression to the active defense of host against virus. With the development of high throughput technology, large amounts of PRI information is available for computationally predicting unknown PRIs. In recent years, a number of computational methods for predicting PRIs have been developed in the literature, which usually artificially construct negative samples based on verified nonredundant datasets of PRIs to train classifiers. However, such negative samples are not real negative samples, some even may be unknown positive samples. Consequently, the classifiers trained with such training datasets cannot achieve satisfactory prediction performance. In this paper, we propose a novel method PRIPU that employs biased-support vector machine (SVM) for predicting Protein-RNA Interactions using only Positive and Unlabeled examples. To the best of our knowledge, this is the first work that predicts PRIs using only positive and unlabeled samples. We first collect known PRIs as our benchmark datasets and extract sequence-based features to represent each PRI. To reduce the dimension of feature vectors for lowering computational cost, we select a subset of features by a filter-based feature selection method. Then, biased-SVM is employed to train prediction models with different PRI datasets. To evaluate the new method, we also propose a new performance measure called explicit positive recall (EPR), which is specifically suitable for the task of learning positive and unlabeled data. Experimental results over three datasets show that our method not only outperforms four existing methods, but also is able to predict unknown PRIs. Source code, datasets and related documents of PRIPU are available at: http://admis.fudan.edu.cn/projects/pripu.htm .
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Kamaludin, Hazalila, Hairulnizam Mahdin e Jemal H. Abawajy. "Filtering Redundant Data from RFID Data Streams". Journal of Sensors 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/7107914.
Testo completoAbstract (sommario):
Radio Frequency Identification (RFID) enabled systems are evolving in many applications that need to know the physical location of objects such as supply chain management. Naturally, RFID systems create large volumes of duplicate data. As the duplicate data wastes communication, processing, and storage resources as well as delaying decision-making, filtering duplicate data from RFID data stream is an important and challenging problem. Existing Bloom Filter-based approaches for filtering duplicate RFID data streams are complex and slow as they use multiple hash functions. In this paper, we propose an approach for filtering duplicate data from RFID data streams. The proposed approach is based on modified Bloom Filter and uses only a single hash function. We performed extensive empirical study of the proposed approach and compared it against the Bloom Filter, d-Left Time Bloom Filter, and the Count Bloom Filter approaches. The results show that the proposed approach outperforms the baseline approaches in terms of false positive rate, execution time, and true positive rate.
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KOBAYASHI, SATOSHI, e TAKASHI YOKOMORI. "FAMILIES OF NONCOUNTING LANGUAGES AND THEIR LEARNABILITY FROM POSITIVE DATA". International Journal of Foundations of Computer Science 07, n. 04 (dicembre 1996): 309–27. http://dx.doi.org/10.1142/s0129054196000221.
Testo completoAbstract (sommario):
This paper introduces some subclasses of noncounting languages and presents some results on the learnability of the classes from positive data. We first establish several relationships among the language classes introduced and the class of reversible languages. Especially, we introduce the notion of local parsability, and define a class (k, l)-CLTS, which is a subclass of the class of concatenations of strictly locally testable languages. We show its close relation to the class of reversible languages. We then study on the relationship between the closure of the Boolean operations and the learnability in the limit from positive data only. Further, we explore the learnability question of some subclasses of noncounting languages in the model of identification in the limit from positive data. In particular, we show that, for each k, l≥1, (k, l)-CLTS is identifiable in the limit from positive data using reversible automata with the conjectures updated in polynomial time. Some possible applications of the result are also briefly discussed.
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Sakai, Tomoya, e Nobuyuki Shimizu. "Covariate Shift Adaptation on Learning from Positive and Unlabeled Data". Proceedings of the AAAI Conference on Artificial Intelligence 33 (17 luglio 2019): 4838–45. http://dx.doi.org/10.1609/aaai.v33i01.33014838.
Testo completoAbstract (sommario):
The goal of binary classification is to identify whether an input sample belongs to positive or negative classes. Usually, supervised learning is applied to obtain a classification rule, but in real-world applications, it is conceivable that only positive and unlabeled data are accessible for learning, which is called learning from positive and unlabeled data (PU learning). Furthermore, in practice, data distributions are likely to differ between training and testing due to, for example, time variation and domain shift. The covariate shift is a dataset shift situation, where distributions of covariates (inputs) differ between training and testing, but the input-output relation is the same. In this paper, we address the PU learning problem under the covariate shift. We propose an importanceweighted PU learning method and reveal in which situations the importance-weighting is necessary. Moreover, we derive the convergence rate of the proposed method under mild conditions and experimentally demonstrate its effectiveness.
Tesi sul tema "Positive-only data"
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Mitchell, Andrew Computer Science & Engineering Faculty of Engineering UNSW. "An approach to boosting from positive-only data". Awarded by:University of New South Wales. Computer Science and Engineering, 2004. http://handle.unsw.edu.au/1959.4/20678.
Testo completoAbstract (sommario):
Ensemble techniques have recently been used to enhance the performance of machine learning methods. However, current ensemble techniques for classification require both positive and negative data to produce a result that is both meaningful and useful. Negative data is, however, sometimes difficult, expensive or impossible to access. In this thesis a learning framework is described that has a very close relationship to boosting. Within this framework a method is described which bears remarkable similarities to boosting stumps and that does not rely on negative examples. This is surprising since learning from positive-only data has traditionally been difficult. An empirical methodology is described and deployed for testing positive-only learning systems using commonly available multiclass datasets to compare these learning systems with each other and with multiclass learning systems. Empirical results show that our positive-only boosting-like method learns, using stumps as a base learner and from positive data only, successfully, and in the process does not pay too heavy a price in accuracy compared to learners that have access to both positive and negative data. We also describe methods of using positive-only learners on multiclass learning tasks and vice versa and empirically demonstrate the superiority of our method of learning in a boosting-like fashion from positive-only data over a traditional multiclass learner converted to learn from positive-only data. Finally we examine some alternative frameworks, such as when additional unlabelled training examples are given. Some theoretical justifications of the results and methods are also provided.
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Tavares, Lucas Alves. "O envolvimento da proteína adaptadora 1 (AP-1) no mecanismo de regulação negativa do receptor CD4 por Nef de HIV-1". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17136/tde-06012017-113215/.
Testo completoAbstract (sommario):
O Vírus da Imunodeficiência Humana (HIV) é o agente etiológico da Síndrome da Imunodeficiência Adquirida (AIDS). A AIDS é uma doença de distribuição mundial, e estima-se que existam atualmente pelo menos 36,9 milhões de pessoas infectadas com o vírus. Durante o seu ciclo replicativo, o HIV promove diversas alterações na fisiologia da célula hospedeira a fim de promover sua sobrevivência e potencializar a replicação. A rápida progressão da infecção pelo HIV-1 em humanos e em modelos animais está intimamente ligada à função da proteína acessória Nef. Dentre as diversas ações de Nef está a regulação negativa de proteínas importantes na resposta imunológica, como o receptor CD4. Sabe-se que esta ação resulta da indução da degradação de CD4 em lisossomos, mas os mecanismos moleculares envolvidos ainda são totalmente elucidados. Nef forma um complexo tripartite com a cauda citosólica de CD4 e a proteína adaptadora 2 (AP-2), em vesículas revestidas por clatrina nascentes, induzindo a internalização e degradação lisossomal de CD4. Pesquisas anteriores demonstraram que o direcionamento de CD4 aos lisossomos por Nef envolve a entrada do receptor na via dos corpos multivesiculares (MVBs), por um mecanismo atípico, pois, embora não necessite da ubiquitinação de carga, depende da ação de proteínas que compõem os ESCRTs (Endosomal Sorting Complexes Required for Transport) e da ação de Alix, uma proteína acessória da maquinaria ESCRT. Já foi reportado que Nef interage com subunidades dos complexos AP-1, AP-2, AP-3 e Nef não parece interagir com subunidades de AP-4 e AP-5. Entretanto, o papel da interação de Nef com AP-1 e AP-3 na regulação negativa de CD4 ainda não está totalmente elucidado. Ademais, AP-1, AP-2 e AP-3 são potencialmente heterogêneos devido à existência de isoformas múltiplas das subunidades codificadas por diferentes genes. Todavia, existem poucos estudos para demonstrar se as diferentes combinações de isoformas dos APs são formadas e se possuem propriedades funcionais distintas. O presente trabalho procurou identificar e caracterizar fatores celulares envolvidos na regulação do tráfego intracelular de proteínas no processo de regulação negativa de CD4 induzido por Nef. Mais especificamente, este estudo buscou caracterizar a participação do complexo AP-1 na modulação negativa de CD4 por Nef de HIV-1, através do estudo funcional das duas isoformas de ?-adaptina, subunidades de AP-1. Utilizando a técnica de Pull-down demonstramos que Nef é capaz de interagir com ?2. Além disso, nossos dados de Imunoblot indicaram que a proteína ?2-adaptina, e não ?1-adaptina, é necessária no processo de degradação lisossomal de CD4 por Nef e que esta participação é conservada para degradação de CD4 por Nef de diferentes cepas virais. Ademais, por citometria de fluxo, o silenciamento de ?2, e não de ?1, compromete a diminuição dos níveis de CD4 por Nef da membrana plasmática. A análise por imunofluorêsncia indireta também revelou que a diminuição dos níveis de ?2 impede a redistribuição de CD4 por Nef para regiões perinucleares, acarretando no acúmulo de CD4, retirados por Nef da membrana plasmática, em endossomos primários. A depleção de ?1A, outra subunidade de AP-1, acarretou na diminuição dos níveis celulares de ?2 e ?1, bem como, no comprometimento da eficiente degradação de CD4 por Nef. Além disso, foi possível observar que, ao perturbar a maquinaria ESCRT via super-expressão de HRS (uma subunidade do complexo ESCRT-0), ocorreu um acumulo de ?2 em endossomos dilatados contendo HRS-GFP, nos quais também detectou-se CD4 que foi internalizado por Nef. Em conjunto, os resultados indicam que ?2-adaptina é uma importante molécula para o direcionamento de CD4 por Nef para a via ESCRT/MVB, mostrando ser uma proteína relevante no sistema endo-lisossomal. Ademais, os resultados indicaram que as isoformas ?-adaptinas não só possuem funções distintas, mas também parecem compor complexos AP-1 com diferentes funções celulares, já que apenas a variante AP-1 contendo ?2, mas não ?1, participa da regulação negativa de CD4 por Nef. Estes estudos contribuem para o melhor entendimento dos mecanismos moleculares envolvidos na atividade de Nef, que poderão também ajudar na melhor compreensão da patogênese do HIV e da síndrome relacionada. Em adição, este trabalho contribui para o entendimento de processos fundamentais da regulação do tráfego de proteínas transmembrana no sistema endo-lisossomal.The Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.
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Mitchell, Andrew R. "An approach to boosting from positive-only data /". 2004. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20050505.025314/index.html.
Testo completoLibri sul tema "Positive-only data"
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van Schalkwyk, François, Stefaan G. Verhulst, Gustavo J. Magalhães, Juan Pane e Johanna Walker. The Social Dynamics of Open Data. African Minds, 2017. http://dx.doi.org/10.47622/978-1-928331-56-8.
Testo completoAbstract (sommario):
The Social Dynamics of Open Data is a collection of peer reviewed papers presented at the 2nd Open Data Research Symposium (ODRS) held in Madrid, Spain, on 5 October 2016. Research is critical to developing a more rigorous and fine-combed analysis not only of why open data is valuable, but how it is valuable and under what specific conditions. The objective of the Open Data Research Symposium and the subsequent collection of chapters published here is to build such a stronger evidence base. This base is essential to understanding what open datas impacts have been to date, and how positive impacts can be enabled and amplified. Consequently, common to the majority of chapters in this collection is the attempt by the authors to draw on existing scientific theories, and to apply them to open data to better explain the socially embedded dynamics that account for open datas successes and failures in contributing to a more equitable and just society.
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Poddubnyy, Denis, e Hildrun Haibel. Treatment: DMARDs. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198734444.003.0021.
Testo completoAbstract (sommario):
In axial spondyloarthritis (axSpA) there is little evidence to support use of classical synthetic disease-modifying antirheumatic drugs (DMARDs), with the majority of studies performed in advanced ankylosing spondylitis. Sulfasalazine is the best investigated DMARD in axSpA. Its positive clinical effect, if any, seems to be more prominent in the presence of peripheral arthritis, although a certain proportion of patients with axial disease might benefit from sulfasalazine therapy. Available data indicate that there is no evidence that methotrexate might be effective in axial disease, and only marginal evidence exists in support of methotrexate use in case of peripheral involvement. No true disease-modifying properties (e.g. retardation of structural damage progression in the spine) have been demonstrated for DMARDs in axSpA to date. Efficacy of a combination therapy (e.g. methotrexate plus sulfasalazine) as well as benefits of methotrexate (or other DMARDs) in addition to tumour necrosis factor α inhibitors in axSpA remain uncertain.
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Falco, Paolo, Henrik Hansen, John Rand, Finn Tarp e Neda Trifković. Good business practices improve productivity in Myanmar’s manufacturing sector: Evidence from two matched employer–employee surveys. 45a ed. UNU-WIDER, 2021. http://dx.doi.org/10.35188/unu-wider/2021/983-9.
Testo completoAbstract (sommario):
We look into the relationship between business practices and enterprise productivity using panel data with matched employer and employee information from Myanmar. The data show that micro, small, and medium-size enterprises in Myanmar typically do only a few modern business practices. Even so, through estimates of value-added functions and labour demand relations we find a positive and economically important association between business practices and productivity. The results are confirmed when we utilize employer–employee information to estimate Mincer-type wage regressions. In combination, the value-added functions and the Mincer regressions show that at least half of the productivity gain from improved business practices stems from selection effects of employment of more productive workers. This sorting channel is important to keep in mind when supporting enterprises in Myanmar’s manufacturing sector through entrepreneurial training activities. While our results indicate that implementation of more structured business practices could be a key ingredient of a private sector development strategy in Myanmar, the full effect of such a strategy may take time to materialize. Moreover, entrepreneurial training should be accompanied by labour market initiatives aimed at improving productive matches of employers and employees.
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Biernacki, Carolina, Prerna Martin, Pablo H. Goldberg e Moira A. Rynn. Treatments for Pediatric Depression. Oxford University Press, 2015. http://dx.doi.org/10.1093/med:psych/9780199342211.003.0012.
Testo completoAbstract (sommario):
Practice guidelines recommend psychosocial interventions for mild or brief cases of pediatric depression. In moderate to severe cases, medication treatment is recommended, with or without cognitive-behavioral therapy (CBT). Fluoxetine and escitalopram are the only antidepressants approved by the U.S. Food & Drug Administration for acute pediatric depression. Among psychosocial interventions, CBT and interpersonal psychotherapy for adolescents (IPT-A) have the largest evidence base for treatment of depressed youth. Combination treatment with CBT and antidepressant medication is superior to treatment with either modality alone. In treatment-resistant depression, a switch in antidepressant is more likely to yield a positive response when medication is used with CBT. Antidepressants should be used judiciously in youths as higher rates of adverse events have been demonstrated, and data from adult trials cannot be systematically extrapolated to youths. Further studies are needed to assess alternative medication and psychosocial treatments as well as factors predictive of treatment response.
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Hitt, Michael A., Susan E. Jackson, Salvador Carmona, Leonard Bierman, Christina E. Shalley e Douglas Michael Wright, a cura di. The Oxford Handbook of Strategy Implementation. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780190650230.001.0001.
Testo completoAbstract (sommario):
Selecting the best strategy is important if a firm is to achieve and maintain a competitive advantage, but many strategies fail not because they are improperly formulated but because they are poorly implemented. Strategy implementation is among the most important and most challenging issues with which top executives must deal, and effective implementation can help firms achieve high performance. Therefore, a greater understanding of the critical dimensions of strategy implementation is needed. This handbook is designed to provide a deeper understanding of topics important for the implementation of strategy. There are three major sections of the book: resources and governance, managing human capital, and accounting control systems. Resources must be acquired, developed, and configured to create the capabilities needed for implementing a firm’s strategy. However, because of the dynamic competitive landscapes in which most firms operate, strategies frequently change. Corporate governance not only guides the formulation of appropriate strategies but also ensures that proper implementation actions are taken. Because the most important resource for implementing strategy is human capital, the firm must engage in highly effective human resource management practices that attract, motivate, develop, and retain the highest quality human talent available. As a result, effective workforce management at all levels in the organization is essential to successful strategy implementation. Managing assets and controlling managerial behavior are critical to strategy implementation: assets can be managed and managerial behavior controlled using accounting-based data. The careful design of such systems promotes innovation and creative activity and identifies earnings, thereby promoting positive managerial actions to achieve desired financial outcomes.
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Wellman, James, Katie Corcoran e Kate Stockly. High on God. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780199827718.001.0001.
Testo completoAbstract (sommario):
Humans are homo duplex, seeking to be individuals but knowing this is only possible in communities. Thus, humans struggle to integrate these two sides of their nature. Megachurches have been enormously successful at resolving this struggle. How do they do it, and what is it about their structure and rituals that makes so many feel as if they are high on God? The affective energies and emotional valences that characterize religious ecstasy are the primary focus of our study of megachurches. Empirically, humans want and desire forms of what Randall Collins calls “emotional energy.” Drawing on extensive qualitative and quantitative data on twelve nationally representative megachurches, we identify six desires that megachurches evoke and meet: acceptance, awe and spiritual stimulation, reliable leadership, deliverance, purpose, and solidarity in a community of like-minded others. Megachurches satisfy these desires through co-presence—being in the presence of other desiring people—a shared mood achieved through powerful musical worship services, a mutual focus of attention on the charismatic senior pastor who acts as an emotional charging agent, transformative altar calls, service opportunities, and small-group participation. This interaction ritual chain solidifies attendees’ commitment and group loyalty, and keeps them coming back to be recharged. Megachurches also have a dark side: they are known for their highly publicized scandals often involving malfeasance of the senior pastor. After examining the positive and negative sides to megachurches, we conclude that they successfully meet the desire of humans to flourish as individuals and to do so in a group.
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Honorato, Hercules Guimarães. Relato de uma experiência acadêmica: O "eu" professor-pesquisador - Vol III. Brazil Publishing, 2021. http://dx.doi.org/10.31012/978-65-5861-378-7.
Testo completoAbstract (sommario):
This study aims to present the plurality of the teacher’s perception, which emerges from the actions taken to minimize the difficulties that come up in remote education. Its relevance is found in the actions and reactions of those involved, and make up possibilities for generating public policies that motivate and foster quality education. The following research question guided this work: What lessons could be learned by those involved in their teaching practice after schools reopen? An exploratory research was carried out, by choosing the methodological approach of qualitative research. Data collection was performed using an online questionnaire, directed to teachers who worked in the classroom and started working in remote education. Sharing knowledge is complex and demands a variety of actions, interventions, processes that, however sophisticated the technology used, it certainly does not allow to develop all the strategies that the teacher uses in the classroom. Technologies help with physical distance. But we believe the exchange that happens naturally between teacher and student, and between student and student, exists only when everyone is in the same physical environment, under the same physical and human conditions, especially in basic education. The lessons learned: (i) improve our training or post-training with the introduction of disciplines related to digital and technological means; (ii) understand that remote education is a possibility to be applied in our teaching practice; (iii) include viable teaching, learning and assessment alternatives in the Political Pedagogical Project; (iv) at parent-teacher conferences or class meetings, seek to collect all possible observations, both positive and negative. We need to considerate new routes, minimize the questions that arise during practice, in order to adapt to the new technological strategies of the art of teaching.
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Jirström, Magnus, Maria Archila Bustos e Sarah Alobo Loison. African Smallholder Farmers on the Move: Farm and Non-Farm Trends for Six Sub-Saharan African Countries, 2002–15. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198799283.003.0002.
Testo completoAbstract (sommario):
This chapter provides a broad descriptive background of central aspects of smallholder agriculture in six countries in sub-Saharan Africa (SSA). It offers an up-to-date picture of the current trends of crop production, area productivity, levels of commercialization, and sources of cash incomes among 2,500 farming households. Structured around smallholder production, commercialization, and diversification in the period 2002–15, the chapter points on the one hand at persistent challenges such as low crop yields, low levels of output per farm, and a high degree of subsistence farming, and on the other hand at positive change over time in terms of growth in crop production and increasing levels of commercialization. It points at large variations not only between countries and time periods but also at the village levels, where gaps in crop productivity between farms remain large. Implicitly it points at the potential yet to be exploited in the SSA smallholder sector.
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Guerin, Dava, Terry Bivens, Jack E. Davis e Floyd Scholz. The Eagle on My Arm. University Press of Kentucky, 2020. http://dx.doi.org/10.5810/kentucky/9780813180021.001.0001.
Testo completoAbstract (sommario):
The Eagle on My Arm details the journey to recovery of Vietnam veteran Patrick Bradley. Enlisting at the age of eighteen, Bradley was mortified by the scenes in the North Vietnam jungles, and found himself unable to cope. At a psychiatrist’s recommendation, Bradley traveled to the Canadian wilderness where he spent three years studying and documenting bald eagles and their behavior. He made groundbreaking discoveries during his research, linking the use of chemical DDT to the decrease in southern bald eagle populations. Additionally, he made notable progress in his recovery, able to better control his previously unmitigated anger and rage. Bradley teamed up with other veterans to form the Avian Veteran Alliance in 2015, a non-profit that pairs wounded warriors with injured birds of prey. Where the Eagles Soar, written by biographers Dava Guerin and Terry Bivens, is one of only a handful of books concerned with the unique link between avian therapy and wounded warrior recovery. Introducing the psychiatric benefits of avian and animal therapy is crucial to the cultural climate regarding mental health, and sheds light on positive and exciting alternatives in the study of PTSD among war veterans.
Capitoli di libri sul tema "Positive-only data"
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Wang, Xiaoling, Zhen Xu, Chaofeng Sha, Martin Ester e Aoying Zhou. "Semi-supervised Learning from Only Positive and Unlabeled Data Using Entropy". In Web-Age Information Management, 668–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14246-8_64.
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Zuluaga, Maria A., Don Hush, Edgar J. F. Delgado Leyton, Marcela Hernández Hoyos e Maciej Orkisz. "Learning from Only Positive and Unlabeled Data to Detect Lesions in Vascular CT Images". In Lecture Notes in Computer Science, 9–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23626-6_2.
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Vrolijk, Paula, e Renske Keizer. "Children’s Living Arrangements After Divorce and the Quality of the Father-Child Relationship; Father Involvement as an Important Underlying Mechanism". In European Studies of Population, 101–29. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-68479-2_6.
Testo completoAbstract (sommario):
AbstractUsing data from the multi-actor Divorce in Flanders survey, this study aimed to provide a more comprehensive understanding of linkages between children’s living arrangements after divorce and father-child relationship quality. First, we tested whether father involvement and co-parental relationship quality explained linkages between living arrangements and father-child relationship quality. Second, we examined whether child’s loyalty conflicts and child’s sex moderated associations between living arrangements and father-child relationship quality. Finally, we explored whether results differed when fathers or children reported on their relationship. Results show that father-child relationship quality (irrespectively of the reporter) was significantly higher for children living in JPC but only compared to children who live solely with their mother. Furthermore, father involvement explained the association between living arrangements and father-child relationship quality (again irrespectively of the reporter). The co-parental relationship also explained part of this association, but only when children reported on father-child relationship quality. The association between children’s living arrangement and father-child relationship quality was stronger for sons than daughters. This association did not differ by loyalty conflicts. These findings highlight the importance of enabling fathers to remain involved after divorce and having a positive co-parental relationship for maintaining high quality relationships between fathers and children.
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Genoni, Andreas, Jean Philippe Décieux, Andreas Ette e Nils Witte. "Setting up Probability-Based Online Panels of Migrants with a Push-to-Web Approach: Lessons Learned from the German Emigration and Remigration Panel Study (GERPS)". In IMISCOE Research Series, 289–307. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67498-4_16.
Testo completoAbstract (sommario):
AbstractWe address two major challenges in setting up probability-based online panels of migrants, using the German Emigration and Remigration Panel Study (GERPS) as an example. The first challenge is potential spatial and social selectivity in unit response when using push-to-web recruitment. To address the first challenge, we draw on a split ballot experiment with return migrants in wave 1 of GERPS. The related analysis uses population register data and geo data. We use logistic regressions to compare unit nonresponse between a push-to-web-only control group (n = 5999) and two sub-samples (each n = 1000) with optional paper and pencil interviews (PAPI). The second challenge is panel attrition. To address the second challenge, we investigate the role of individual-level and survey-related factors for panel consent. The regression analysis uses GERPS data of first-wave respondents, estimating panel consent rates for responding remigrants in general (n = 6395) and in the experiment sample (n = 2130). We find that the provision of an optional paper questionnaire marginally increases the likelihood of response. The positive correlation of PAPI and response rate, however, is counterbalanced by a negative correlation with the likelihood of panel consent. This suggests a trade-off scenario to the detriment of either response rates or panel participation rates.
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Nkuba, Michael Robert, Raban Chanda, Gagoitseope Mmopelwa, Akintayo Adedoyin, Margaret Najjingo Mangheni, David Lesolle e Edward Kato. "Indigenous and Scientific Forecasts on Climate Change Perceptions of Arable Farmers: Rwenzori Region, Western Uganda". In African Handbook of Climate Change Adaptation, 1685–703. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_113.
Testo completoAbstract (sommario):
AbstractDespite the dissemination of climate information from national meteorological systems, arable farmers still have challenges of dealing with climate-related risks. This study investigated the effect of using indigenous knowledge-based forecasts (IFs) and scientific knowledge-based forecasts (SFs) on the climate change perceptions of arable farmers in the Rwenzori region, Western Uganda. Data on socio-economic characteristics, use of forecasts, and climate change perceptions was collected from 580 arable farmers and the probit model was used in the analysis. The findings indicated that use of IFs only increased the likelihood of perceiving increase in the frequency in occurrences of droughts and floods. Using both SFs and IFs had a significant positive effect on perception of unpredictable rains and the increase in drought incidence among arable farmers. Although forecasts are important drivers of perceptions, other factors, such as gender, social capital, and dissemination of climate change information by radio, enhance climate change perceptions. Active participation of arable farmers in the dissemination of forecasts by national meteorological services could improve perceptions of climate related risks.
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Laskar, Pia. "Pink Porn Economy: Genealogies of Transnational LGBTQ Organising". In Pluralistic Struggles in Gender, Sexuality and Coloniality, 177–207. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47432-4_7.
Testo completoAbstract (sommario):
Abstract Studying pre-2000s pink porn magazines reveals the importance of politics in-between in the development of LGBTQ transnational organising in the twentieth century. The usual historical narratives of LGBTQ politics in the North are based on medical or legislative documents or on self-identified queers’ descriptions of their own interactions with these discourses. However, these discourses and data only capture parts of how twentieth-century queers developed sexual subjectivity, became nationally and transnationally organised, and conducted sexual politics. This chapter uses Claire Colebrook’s (Understanding Deleuze. Australia: Allen and Unwin, 2002) feminist engagement in Deleuze’s and Guattari’s concept device to discuss transnational political networks that rhizomatically connected the makers, disseminators and subscribers of male same-sex porn magazines produced in Denmark and Sweden between 1960 and 1980. The concepts enable an analysis of the messy entanglement of desire, subjectivity processes, consumption, organising and activism, and of the shaping of certain queer communities of belonging while also excluding others. The application of gender analysis to the entanglement of pink porn economies in queer transnational networks sheds a genealogical light on the historical division between the emergence of vis-à-vis lesbian and gay networks and politics—and on the tensions between them regarding so-called positive or negative sexual rights in the decades to come.
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Ntouros, Vasileios, Nikolaos Kampelis, Martina Senzacqua, Theoni Karlessi, Margarita-Niki Assimakopoulos, Dionysia Kolokotsa e Cristina Cristalli. "Smart Meter Awareness in Italy, Ancona". In Smart and Sustainable Planning for Cities and Regions, 47–66. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57764-3_4.
Testo completoAbstract (sommario):
AbstractSmart meters, one of the crucial enablers of the smart-grid concept and cornerstones in smart planning for cities, offer the opportunity for consumers to address their energy consumption effectively through timely and accurate data on their energy usage. However, previous studies have shown that smart meters may not lead to the desired energy savings unless actively used by households. To this end, the research presented in this paper investigates the penetration of smart meters at community level and explores how such a metering system can help people to understand and manage their energy use better. It examines the awareness about smart meters, looks into their presence in current accommodation and focuses on the views people have about smart meters. For this purpose, a questionnaire was prepared and distributed to a group of individuals residing in the wide area of Ancona province in Italy. Although the deployment of modern second-generation smart meters started in 2017 replacing the outdated smart meters massively installed in the 2000s, the results show low-to-moderate levels of awareness of modern smart meters among the respondents and a low presence of second-generation metering devices in their current accommodation. However, the general view expressed by the participants about smart meters is positive. The findings demonstrate that respondents are in need not only of a gauge that measures energy consumption but also of a tool that assists them to manage effectively their energy use.
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von Weizsäcker, Carl Christian, e Hagen M. Krämer. "Land". In Saving and Investment in the Twenty-First Century, 105–36. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75031-2_5.
Testo completoAbstract (sommario):
AbstractPrivate wealth is comprised in part of capitalized future land rents. The Golden Rule of Accumulation is preserved even if we introduce land into our meta-model. Urban land is far more valuable than agricultural land. The risk tied to land leads to a reduction in its value in the form of a “risk premium” α > 0. Land rents can be taxed without any possibility of the tax being passed on to tenants and without loss of efficiency. If the tax is offset by a reduction in income tax, their taxation can even give rise to efficiency gains and positive distributive effects. The possibility of government intervention in the residential rental market represents a further risk for landowners. The sensitivity of the value of land to changes in the interest rate and hence the risk premium α rise with falling interest rates. In light of these many different risks, land as investment can only to a limited extent be a substitute for government bonds and hence for increasing private wealth by way of public debt. We calculate the value of land as asset category in the OECD plus China region. To this end, we primarily rely on data from statistical offices that provide figures for land in their national balance sheets. Our calculations show that the value of land in the countries of the OECD plus China region is about twice annual consumption in the region.
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Zimba, Josephine M., e Emma T. Liwenga. "Effects of conservation agriculture on farmers' livelihoods in the face of climate change in Balaka district, Malawi." In Climate change impacts and sustainability: ecosystems of Tanzania, 44–58. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789242966.0044.
Testo completoAbstract (sommario):
Abstract Conservation agriculture (CA) has been highly promoted due to its potential to ensure high crop yields even in the face of changes in climatic factors. However, the actual benefits associated with CA are not only focused on food security but are also site specific. This study sought to understand the benefits of CA in improving livelihoods in a changing climate in Hanjahanja and Sawali sections of Bazale Extension Planning Area in Balaka District. Specifically, it analysed CA's contribution to farmers' livelihoods and also the challenges and opportunities of CA in climate change adaptation. Data was collected through household surveys (n = 153), key informant interviews (n = 9), focus group discussions and field observations. The study found that due to CA adoption, the majority of the farmers in both Hanjahanja and Sawali sections had realized positive livelihood outcomes, mainly through improved food security and increased incomes. Despite the similarity, Hanjahanja farmers reported decrease in yields in seasons marred by floods. However, farmers faced several challenges due to CA adoption, which included high labour demands, rainfall variability and lack of inputs. Even so, improvement in soil moisture, soil erosion control, improved food security, presence of several institutions and enabling environment offered more opportunities of CA in adapting to climate change. CA, therefore, improves the livelihoods of the farmers except in times of floods. Hence, deliberate policies by the government to promote adoption of CA are required to take advantage of the benefits of CA. Research should also be done on how best to reduce the negative effects of CA on farmers' livelihoods.
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Viswanath, Navin, e Rajshekhar Sunderraman. "A Paraconsistent Relational Data Model". In Handbook of Research on Innovations in Database Technologies and Applications, 18–27. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-242-8.ch003.
Testo completoAbstract (sommario):
Typically, relational databases operate under the Closed World Assumption (CWA) of Reiter (Reiter, 1987). The CWA is a meta-rule that says that given a knowledge base KB and a sentence P, if P is not a logical consequence of KB, assume ~P (the negation of P). Thus, we explicitly represent only positive facts in a knowledge base. A negative fact is implicit if its positive counterpart is not present. Under the CWA we presume that our knowledge about the world is complete i.e. there are no “gaps” in our knowledge of the real world. The Open World Assumption (OWA) is the opposite point of view. Here, we “admit” that our knowledge of the real world is incomplete. Thus we store everything we know about the world – positive and negative. Consider a database which simply contains the information “Tweety is a bird”. Assume that we want to ask this database the query “Does Tweety fly?”. Under the CWA, since we assume that there are no gaps in our knowledge, every query returns a yes/no answer. In this case we get the answer “no” because there is no information in the database stating that Tweety can fly. However, under the OWA, the answer to the query is “unknown”. i.e. the database does not know whether Tweety flies or not. We would obtain a “no” answer to this query under the OWA only if it was explicitly stated in the database that Tweety does not fly.
Atti di convegni sul tema "Positive-only data"
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Elkan, Charles, e Keith Noto. "Learning classifiers from only positive and unlabeled data". In the 14th ACM SIGKDD international conference. New York, New York, USA: ACM Press, 2008. http://dx.doi.org/10.1145/1401890.1401920.
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Arjannikov, Tom, e George Tzanetakis. "Histogram-Based Asymmetric Relabeling for Learning from Only Positive and Unlabeled Data". In 2017 16th IEEE International Conference on Machine Learning and Applications (ICMLA). IEEE, 2017. http://dx.doi.org/10.1109/icmla.2017.000-8.
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Tomeo, Paolo, Ignacio Fernández-Tobías, Tommaso Di Noia e Iván Cantador. "Exploiting Linked Open Data in Cold-start Recommendations with Positive-only Feedback". In CERI '16: 4th Spanish Conference in Information Retrieval. New York, NY, USA: ACM, 2016. http://dx.doi.org/10.1145/2934732.2934745.
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Daneshpazhouh, Armin, e Ashkan Sami. "Semi-supervised outlier detection with only positive and unlabeled data based on fuzzy clustering". In 2013 5th Conference on Information and Knowledge Technology (IKT). IEEE, 2013. http://dx.doi.org/10.1109/ikt.2013.6620091.
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Su, Guangxin, Weitong Chen e Miao Xu. "Positive-Unlabeled Learning from Imbalanced Data". In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/412.
Testo completoAbstract (sommario):
Positive-unlabeled (PU) learning deals with the binary classification problem when only positive (P) and unlabeled (U) data are available, without negative (N) data. Existing PU methods perform well on the balanced dataset. However, in real applications such as financial fraud detection or medical diagnosis, data are always imbalanced. It remains unclear whether existing PU methods can perform well on imbalanced data. In this paper, we explore this problem and propose a general learning objective for PU learning targeting specially at imbalanced data. By this general learning objective, state-of-the-art PU methods based on optimizing a consistent risk can be adapted to conquer the imbalance. We theoretically show that in expectation, optimizing our learning objective is equivalent to learning a classifier on the oversampled balanced data with both P and N data available, and further provide an estimation error bound. Finally, experimental results validate the effectiveness of our proposal compared to state-of-the-art PU methods.
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Shinoda, Kazuhiko, Hirotaka Kaji e Masashi Sugiyama. "Binary Classification from Positive Data with Skewed Confidence". In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/460.
Testo completoAbstract (sommario):
Positive-confidence (Pconf) classification [Ishida et al., 2018] is a promising weakly-supervised learning method which trains a binary classifier only from positive data equipped with confidence. However, in practice, the confidence may be skewed by bias arising in an annotation process. The Pconf classifier cannot be properly learned with skewed confidence, and consequently, the classification performance might be deteriorated. In this paper, we introduce the parameterized model of the skewed confidence, and propose the method for selecting the hyperparameter which cancels out the negative impact of the skewed confidence under the assumption that we have the misclassification rate of positive samples as a prior knowledge. We demonstrate the effectiveness of the proposed method through a synthetic experiment with simple linear models and benchmark problems with neural network models. We also apply our method to drivers’ drowsiness prediction to show that it works well with a real-world problem where confidence is obtained based on manual annotation.
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Zhang, Chuang, Chen Gong, Tengfei Liu, Xun Lu, Weiqiang Wang e Jian Yang. "Online Positive and Unlabeled Learning". In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/311.
Testo completoAbstract (sommario):
Positive and Unlabeled learning (PU learning) aims to build a binary classifier where only positive and unlabeled data are available for classifier training. However, existing PU learning methods all work on a batch learning mode, which cannot deal with the online learning scenarios with sequential data. Therefore, this paper proposes a novel positive and unlabeled learning algorithm in an online training mode, which trains a classifier solely on the positive and unlabeled data arriving in a sequential order. Specifically, we adopt an unbiased estimate for the loss induced by the arriving positive or unlabeled examples at each time. Then we show that for any coming new single datum, the model can be updated independently and incrementally by gradient based online learning method. Furthermore, we extend our method to tackle the cases when more than one example is received at each time. Theoretically, we show that the proposed online PU learning method achieves low regret even though it receives sequential positive and unlabeled data. Empirically, we conduct intensive experiments on both benchmark and real-world datasets, and the results clearly demonstrate the effectiveness of the proposed method.
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Yang, Pengyi, Wei Liu e Jean Yang. "Positive unlabeled learning via wrapper-based adaptive sampling". In Twenty-Sixth International Joint Conference on Artificial Intelligence. California: International Joint Conferences on Artificial Intelligence Organization, 2017. http://dx.doi.org/10.24963/ijcai.2017/457.
Testo completoAbstract (sommario):
Learning from positive and unlabeled data frequently occurs in applications where only a subset of positive instances is available while the rest of the data are unlabeled. In such scenarios, often the goal is to create a discriminant model that can accurately classify both positive and negative data by modelling from labeled and unlabeled instances. In this study, we propose an adaptive sampling (AdaSampling) approach that utilises prediction probabilities from a model to iteratively update the training data. Starting with equal prior probabilities for all unlabeled data, our method "wraps" around a predictive model to iteratively update these probabilities to distinguish positive and negative instances in unlabeled data. Subsequently, one or more robust negative set(s) can be drawn from unlabeled data, according to the likelihood of each instance being negative, to train a single classification model or ensemble of models.
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Viola, Rémi, Rémi Emonet, Amaury Habrard, Guillaume Metzler e Marc Sebban. "Learning from Few Positives: a Provably Accurate Metric Learning Algorithm to Deal with Imbalanced Data". In Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/298.
Testo completoAbstract (sommario):
Learning from imbalanced data, where the positive examples are very scarce, remains a challenging task from both a theoretical and algorithmic perspective. In this paper, we address this problem using a metric learning strategy. Unlike the state-of-the-art methods, our algorithm MLFP, for Metric Learning from Few Positives, learns a new representation that is used only when a test query is compared to a minority training example. From a geometric perspective, it artificially brings positive examples closer to the query without changing the distances to the negative (majority class) data. This strategy allows us to expand the decision boundaries around the positives, yielding a better F-Measure, a criterion which is suited to deal with imbalanced scenarios. Beyond the algorithmic contribution provided by MLFP, our paper presents generalization guarantees on the false positive and false negative rates. Extensive experiments conducted on several imbalanced datasets show the effectiveness of our method.
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Xu, Yixing, Chang Xu, Chao Xu e Dacheng Tao. "Multi-Positive and Unlabeled Learning". In Twenty-Sixth International Joint Conference on Artificial Intelligence. California: International Joint Conferences on Artificial Intelligence Organization, 2017. http://dx.doi.org/10.24963/ijcai.2017/444.
Testo completoAbstract (sommario):
The positive and unlabeled (PU) learning problem focuses on learning a classifier from positive and unlabeled data. Some methods have been developed to solve the PU learning problem. However, they are often limited in practical applications, since only binary classes are involved and cannot easily be adapted to multi-class data. Here we propose a one-step method that directly enables multi-class model to be trained using the given input multi-class data and that predicts the label based on the model decision. Specifically, we construct different convex loss functions for labeled and unlabeled data to learn a discriminant function F. The theoretical analysis on the generalization error bound shows that it is no worse than k√k times of the fully supervised multi-class classification methods when the size of the data in k classes is of the same order. Finally, our experimental results demonstrate the significance and effectiveness of the proposed algorithm in synthetic and real-world datasets.
Rapporti di organizzazioni sul tema "Positive-only data"
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Treadwell, Jonathan R., James T. Reston, Benjamin Rouse, Joann Fontanarosa, Neha Patel e Nikhil K. Mull. Automated-Entry Patient-Generated Health Data for Chronic Conditions: The Evidence on Health Outcomes. Agency for Healthcare Research and Quality (AHRQ), marzo 2021. http://dx.doi.org/10.23970/ahrqepctb38.
Testo completoAbstract (sommario):
Background. Automated-entry consumer devices that collect and transmit patient-generated health data (PGHD) are being evaluated as potential tools to aid in the management of chronic diseases. The need exists to evaluate the evidence regarding consumer PGHD technologies, particularly for devices that have not gone through Food and Drug Administration evaluation. Purpose. To summarize the research related to automated-entry consumer health technologies that provide PGHD for the prevention or management of 11 chronic diseases. Methods. The project scope was determined through discussions with Key Informants. We searched MEDLINE and EMBASE (via EMBASE.com), In-Process MEDLINE and PubMed unique content (via PubMed.gov), and the Cochrane Database of Systematic Reviews for systematic reviews or controlled trials. We also searched ClinicalTrials.gov for ongoing studies. We assessed risk of bias and extracted data on health outcomes, surrogate outcomes, usability, sustainability, cost-effectiveness outcomes (quantifying the tradeoffs between health effects and cost), process outcomes, and other characteristics related to PGHD technologies. For isolated effects on health outcomes, we classified the results in one of four categories: (1) likely no effect, (2) unclear, (3) possible positive effect, or (4) likely positive effect. When we categorized the data as “unclear” based solely on health outcomes, we then examined and classified surrogate outcomes for that particular clinical condition. Findings. We identified 114 unique studies that met inclusion criteria. The largest number of studies addressed patients with hypertension (51 studies) and obesity (43 studies). Eighty-four trials used a single PGHD device, 23 used 2 PGHD devices, and the other 7 used 3 or more PGHD devices. Pedometers, blood pressure (BP) monitors, and scales were commonly used in the same studies. Overall, we found a “possible positive effect” of PGHD interventions on health outcomes for coronary artery disease, heart failure, and asthma. For obesity, we rated the health outcomes as unclear, and the surrogate outcomes (body mass index/weight) as likely no effect. For hypertension, we rated the health outcomes as unclear, and the surrogate outcomes (systolic BP/diastolic BP) as possible positive effect. For cardiac arrhythmias or conduction abnormalities we rated the health outcomes as unclear and the surrogate outcome (time to arrhythmia detection) as likely positive effect. The findings were “unclear” regarding PGHD interventions for diabetes prevention, sleep apnea, stroke, Parkinson’s disease, and chronic obstructive pulmonary disease. Most studies did not report harms related to PGHD interventions; the relatively few harms reported were minor and transient, with event rates usually comparable to harms in the control groups. Few studies reported cost-effectiveness analyses, and only for PGHD interventions for hypertension, coronary artery disease, and chronic obstructive pulmonary disease; the findings were variable across different chronic conditions and devices. Patient adherence to PGHD interventions was highly variable across studies, but patient acceptance/satisfaction and usability was generally fair to good. However, device engineers independently evaluated consumer wearable and handheld BP monitors and considered the user experience to be poor, while their assessment of smartphone-based electrocardiogram monitors found the user experience to be good. Student volunteers involved in device usability testing of the Weight Watchers Online app found it well-designed and relatively easy to use. Implications. Multiple randomized controlled trials (RCTs) have evaluated some PGHD technologies (e.g., pedometers, scales, BP monitors), particularly for obesity and hypertension, but health outcomes were generally underreported. We found evidence suggesting a possible positive effect of PGHD interventions on health outcomes for four chronic conditions. Lack of reporting of health outcomes and insufficient statistical power to assess these outcomes were the main reasons for “unclear” ratings. The majority of studies on PGHD technologies still focus on non-health-related outcomes. Future RCTs should focus on measurement of health outcomes. Furthermore, future RCTs should be designed to isolate the effect of the PGHD intervention from other components in a multicomponent intervention.
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Carlsson, Mikael, Julián Messina e Oskar Nordström Skans. Firm-Level Shocks and Labor Flows. Inter-American Development Bank, gennaio 2021. http://dx.doi.org/10.18235/0003002.
Testo completoAbstract (sommario):
This paper analyzes how labor ows respond to permanent idiosyncratic shifts in rm-level production functions and demand curves using very detailed Swedish micro data. Shocks to rms physical productivity have only modest eects on rm-level employment decisions. In contrast, the paper documents rapid and substantial employment adjustments through hires and separations in response to rm-level demand shocks. The choice of adjustment margin depends on the sign of the shock: rms adjust through increased hires if these shocks are positive and through increased separations if the shocks are negative.
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Carlsson, Mikael, Julián Messina e Oskar Nordström Skans. Firm-Level Shocks and Labor Flows. Inter-American Development Bank, gennaio 2021. http://dx.doi.org/10.18235/0003002.
Testo completoAbstract (sommario):
This paper analyzes how labor ows respond to permanent idiosyncratic shifts in rm-level production functions and demand curves using very detailed Swedish micro data. Shocks to rms physical productivity have only modest eects on rm-level employment decisions. In contrast, the paper documents rapid and substantial employment adjustments through hires and separations in response to rm-level demand shocks. The choice of adjustment margin depends on the sign of the shock: rms adjust through increased hires if these shocks are positive and through increased separations if the shocks are negative.
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Niconchuk, Michael. Whose Vulnerability? Trauma Recovery in the Reintegration of Former Violent Extremists. RESOLVE Network, giugno 2021. http://dx.doi.org/10.37805/pn2021.16.vedr.
Testo completoAbstract (sommario):
Violent extremism has a trauma problem. Psychological trauma plays a role in the genesis, perpetration, and resolution of violent extremism. Despite evidence attesting to the positive effects of trauma-informed rehabilitation programs and trauma recovery support for armed combatants and criminal offenders, there has been limited donor interest or coordinated policy effort to meaningfully integrate trauma recovery into the design of rehabilitation and reintegration of violent extremists specifically. Research in global mental health confirms trauma is not only relevant to the emergence of violent extremism but is also a consequence of participation in violent extremism. While there is a general dearth of data on the psychobiological markers of trauma among extremist populations specifically, the limited data we have from child recruits, as well as from other conflict-affected populations calls for a more prominent role of psychological rehabilitation and trauma recovery in the reintegration of violent extremists.
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Schnabel, Filipina, e Danielle Aldridge. Effectiveness of EHR-Depression Screening Among Adult Diabetics in an Urban Primary Care Clinic. University of Tennessee Health Science Center, aprile 2021. http://dx.doi.org/10.21007/con.dnp.2021.0003.
Testo completoAbstract (sommario):
Background Diabetes mellitus (DM) and depression are important comorbid conditions that can lead to more serious health outcomes. The American Diabetes Association (ADA) supports routine screening for depression as part of standard diabetes management. The PHQ2 and PHQ9 questionnaires are good diagnostic screening tools used for major depressive disorders in Type 2 diabetes mellitus (DM2). This quality improvement study aims to compare the rate of depression screening, treatment, and referral to behavioral health in adult patients with DM2 pre and post-integration of depression screening tools into the electronic health record (EHR). Methods We conducted a retrospective chart review on patients aged 18 years and above with a diagnosis of DM2 and no initial diagnosis of depression or other mental illnesses. Chart reviews included those from 2018 or prior for before integration data and 2020 to present for after integration. Sixty subjects were randomly selected from a pool of 33,695 patients in the clinic with DM2 from the year 2013-2021. Thirty of the patients were prior to the integration of depression screening tools PHQ2 and PHQ9 into the EHR, while the other half were post-integration. The study population ranged from 18-83 years old. Results All subjects (100%) were screened using PHQ2 before integration and after integration. Twenty percent of patients screened had a positive PHQ2 among subjects before integration, while 10% had a positive PHQ2 after integration. Twenty percent of patients were screened with a PHQ9 pre-integration which accounted for 100% of those subjects with a positive PHQ2. However, of the 10% of patients with a positive PHQ2 post-integration, only 6.7 % of subjects were screened, which means not all patients with a positive PHQ2 were adequately screened post-integration. Interestingly, 10% of patients were treated with antidepressants before integration, while none were treated with medications in the post-integration group. There were no referrals made to the behavior team in either group. Conclusion There is no difference between the prevalence of depression screening before or after integration of depression screening tools in the EHR. The study noted that there is a decrease in the treatment using antidepressants after integration. However, other undetermined conditions could have influenced this. Furthermore, not all patients with positive PHQ2 in the after-integration group were screened with PHQ9. The authors are unsure if the integration of the depression screens influenced this change. In both groups, there is no difference between referrals to the behavior team. Implications to Nursing Practice This quality improvement study shows that providers are good at screening their DM2 patients for depression whether the screening tools were incorporated in the EHR or not. However, future studies regarding providers, support staff, and patient convenience relating to accessibility and availability of the tool should be made. Additional issues to consider are documentation reliability, hours of work to scan documents in the chart, risk of documentation getting lost, and the use of paper that requires shredding to comply with privacy.
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McPhedran, R., K. Patel, B. Toombs, P. Menon, M. Patel, J. Disson, K. Porter, A. John e A. Rayner. Food allergen communication in businesses feasibility trial. Food Standards Agency, marzo 2021. http://dx.doi.org/10.46756/sci.fsa.tpf160.
Testo completoAbstract (sommario):
Background: Clear allergen communication in food business operators (FBOs) has been shown to have a positive impact on customers’ perceptions of businesses (Barnett et al., 2013). However, the precise size and nature of this effect is not known: there is a paucity of quantitative evidence in this area, particularly in the form of randomised controlled trials (RCTs). The Food Standards Agency (FSA), in collaboration with Kantar’s Behavioural Practice, conducted a feasibility trial to investigate whether a randomised cluster trial – involving the proactive communication of allergen information at the point of sale in FBOs – is feasible in the United Kingdom (UK). Objectives: The trial sought to establish: ease of recruitments of businesses into trials; customer response rates for in-store outcome surveys; fidelity of intervention delivery by FBO staff; sensitivity of outcome survey measures to change; and appropriateness of the chosen analytical approach. Method: Following a recruitment phase – in which one of fourteen multinational FBOs was successfully recruited – the execution of the feasibility trial involved a quasi-randomised matched-pairs clustered experiment. Each of the FBO’s ten participating branches underwent pair-wise matching, with similarity of branches judged according to four criteria: Food Hygiene Rating Scheme (FHRS) score, average weekly footfall, number of staff and customer satisfaction rating. The allocation ratio for this trial was 1:1: one branch in each pair was assigned to the treatment group by a representative from the FBO, while the other continued to operate in accordance with their standard operating procedure. As a business-based feasibility trial, customers at participating branches throughout the fieldwork period were automatically enrolled in the trial. The trial was single-blind: customers at treatment branches were not aware that they were receiving an intervention. All customers who visited participating branches throughout the fieldwork period were asked to complete a short in-store survey on a tablet affixed in branches. This survey contained four outcome measures which operationalised customers’: perceptions of food safety in the FBO; trust in the FBO; self-reported confidence to ask for allergen information in future visits; and overall satisfaction with their visit. Results: Fieldwork was conducted from the 3 – 20 March 2020, with cessation occurring prematurely due to the closure of outlets following the proliferation of COVID-19. n=177 participants took part in the trial across the ten branches; however, response rates (which ranged between 0.1 - 0.8%) were likely also adversely affected by COVID-19. Intervention fidelity was an issue in this study: while compliance with delivery of the intervention was relatively high in treatment branches (78.9%), erroneous delivery in control branches was also common (46.2%). Survey data were analysed using random-intercept multilevel linear regression models (due to the nesting of customers within branches). Despite the trial’s modest sample size, there was some evidence to suggest that the intervention had a positive effect for those suffering from allergies/intolerances for the ‘trust’ (β = 1.288, p<0.01) and ‘satisfaction’ (β = 0.945, p<0.01) outcome variables. Due to singularity within the fitted linear models, hierarchical Bayes models were used to corroborate the size of these interactions. Conclusions: The results of this trial suggest that a fully powered clustered RCT would likely be feasible in the UK. In this case, the primary challenge in the execution of the trial was the recruitment of FBOs: despite high levels of initial interest from four chains, only one took part. However, it is likely that the proliferation of COVID-19 adversely impacted chain participation – two other FBOs withdrew during branch eligibility assessment and selection, citing COVID-19 as a barrier. COVID-19 also likely lowered the on-site survey response rate: a significant negative Pearson correlation was observed between daily survey completions and COVID-19 cases in the UK, highlighting a likely relationship between the two. Limitations: The trial was quasi-random: selection of branches, pair matching and allocation to treatment/control groups were not systematically conducted. These processes were undertaken by a representative from the FBO’s Safety and Quality Assurance team (with oversight from Kantar representatives on pair matching), as a result of the chain’s internal operational restrictions.
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Jorgensen, Frieda, Andre Charlett, Craig Swift, Anais Painset e Nicolae Corcionivoschi. A survey of the levels of Campylobacter spp. contamination and prevalence of selected antimicrobial resistance determinants in fresh whole UK-produced chilled chickens at retail sale (non-major retailers). Food Standards Agency, giugno 2021. http://dx.doi.org/10.46756/sci.fsa.xls618.
Testo completoAbstract (sommario):
Campylobacter spp. are the most common bacterial cause of foodborne illness in the UK, with chicken considered to be the most important vehicle for this organism. The UK Food Standards Agency (FSA) agreed with industry to reduce Campylobacter spp. contamination in raw chicken and issued a target to reduce the prevalence of the most contaminated chickens (those with more than 1000 cfu per g chicken neck skin) to below 10 % at the end of the slaughter process, initially by 2016. To help monitor progress, a series of UK-wide surveys were undertaken to determine the levels of Campylobacter spp. on whole UK-produced, fresh chicken at retail sale in the UK. The data obtained for the first four years was reported in FSA projects FS241044 (2014/15) and FS102121 (2015 to 2018). The FSA has indicated that the retail proxy target for the percentage of highly contaminated raw whole retail chickens should be less than 7% and while continued monitoring has demonstrated a sustained decline for chickens from major retailer stores, chicken on sale in other stores have yet to meet this target. This report presents results from testing chickens from non-major retailer stores (only) in a fifth survey year from 2018 to 2019. In line with previous practise, samples were collected from stores distributed throughout the UK (in proportion to the population size of each country). Testing was performed by two laboratories - a Public Health England (PHE) laboratory or the Agri-Food & Biosciences Institute (AFBI), Belfast. Enumeration of Campylobacter spp. was performed using the ISO 10272-2 standard enumeration method applied with a detection limit of 10 colony forming units (cfu) per gram (g) of neck skin. Antimicrobial resistance (AMR) to selected antimicrobials in accordance with those advised in the EU harmonised monitoring protocol was predicted from genome sequence data in Campylobacter jejuni and Campylobacter coli isolates The percentage (10.8%) of fresh, whole chicken at retail sale in stores of smaller chains (for example, Iceland, McColl’s, Budgens, Nisa, Costcutter, One Stop), independents and butchers (collectively referred to as non-major retailer stores in this report) in the UK that are highly contaminated (at more than 1000 cfu per g) with Campylobacter spp. has decreased since the previous survey year but is still higher than that found in samples from major retailers. 8 whole fresh raw chickens from non-major retailer stores were collected from August 2018 to July 2019 (n = 1009). Campylobacter spp. were detected in 55.8% of the chicken skin samples obtained from non-major retailer shops, and 10.8% of the samples had counts above 1000 cfu per g chicken skin. Comparison among production plant approval codes showed significant differences of the percentages of chicken samples with more than 1000 cfu per g, ranging from 0% to 28.1%. The percentage of samples with more than 1000 cfu of Campylobacter spp. per g was significantly higher in the period May, June and July than in the period November to April. The percentage of highly contaminated samples was significantly higher for samples taken from larger compared to smaller chickens. There was no statistical difference in the percentage of highly contaminated samples between those obtained from chicken reared with access to range (for example, free-range and organic birds) and those reared under standard regime (for example, no access to range) but the small sample size for organic and to a lesser extent free-range chickens, may have limited the ability to detect important differences should they exist. Campylobacter species was determined for isolates from 93.4% of the positive samples. C. jejuni was isolated from the majority (72.6%) of samples while C. coli was identified in 22.1% of samples. A combination of both species was found in 5.3% of samples. C. coli was more frequently isolated from samples obtained from chicken reared with access to range in comparison to those reared as standard birds. C. jejuni was less prevalent during the summer months of June, July and August compared to the remaining months of the year. Resistance to ciprofloxacin (fluoroquinolone), erythromycin (macrolide), tetracycline, (tetracyclines), gentamicin and streptomycin (aminoglycosides) was predicted from WGS data by the detection of known antimicrobial resistance determinants. Resistance to ciprofloxacin was detected in 185 (51.7%) isolates of C. jejuni and 49 (42.1%) isolates of C. coli; while 220 (61.1%) isolates of C. jejuni and 73 (62.9%) isolates of C. coli isolates were resistant to tetracycline. Three C. coli (2.6%) but none of the C. jejuni isolates harboured 23S mutations predicting reduced susceptibility to erythromycin. Multidrug resistance (MDR), defined as harbouring genetic determinants for resistance to at least three unrelated antimicrobial classes, was found in 10 (8.6%) C. coli isolates but not in any C. jejuni isolates. Co-resistance to ciprofloxacin and erythromycin was predicted in 1.7% of C. coli isolates. 9 Overall, the percentages of isolates with genetic AMR determinants found in this study were similar to those reported in the previous survey year (August 2016 to July 2017) where testing was based on phenotypic break-point testing. Multi-drug resistance was similar to that found in the previous survey years. It is recommended that trends in AMR in Campylobacter spp. isolates from retail chickens continue to be monitored to realise any increasing resistance of concern, particulary to erythromycin (macrolide). Considering that the percentage of fresh, whole chicken from non-major retailer stores in the UK that are highly contaminated (at more than 1000 cfu per g) with Campylobacter spp. continues to be above that in samples from major retailers more action including consideration of interventions such as improved biosecurity and slaughterhouse measures is needed to achieve better control of Campylobacter spp. for this section of the industry. The FSA has indicated that the retail proxy target for the percentage of highly contaminated retail chickens should be less than 7% and while continued monitoring has demonstrated a sustained decline for chickens from major retailer stores, chicken on sale in other stores have yet to meet this target.