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Publicações

Publicações por LIAAD

2019

Pruned Sets for Multi-Label Stream Classification without True Labels

Autores
Costa Junior, JD; Faria, ER; Silva, JA; Gama, J; Cerri, R;

Publicação
2019 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS (IJCNN)

Abstract
In multi-label classification problems an example can be simultaneously classified into more than one class. This is also a challenging task in Data Streams (DS) classification, where unbounded and non-stationary distributed multi-label data contain multiple concepts that drift at different rates and patterns. In addition, the true labels of the examples may never become available and updating classification models in a supervised fashion is unfeasible. In this paper, we propose a Multi-Label Stream Classification (MLSC) method applying a Novelty Detection (ND) procedure task to update the classification model detecting any new patterns in the examples, which differ in some aspects from observed patterns, in an unsupervised fashion without any external feedback. Although ND is suitable for multi-class stream classification, it is still a not well-investigated task for multi-label problems. We improve a initial work proposed in [1] and extended it with a new Pruned Sets (PS) transformation strategy. The experiments showed that our method presents competitive performances over data sets with different concept drifts, and outperform, in some aspects, the baseline methods.

2019

Contextual One-Class Classification in Data Streams

Autores
Moulton, RH; Viktor, HL; Japkowicz, N; Gama, J;

Publicação
CoRR

Abstract

2019

Uma Análise sobre a Evolução das Preferências Musicais dos Usuários Utilizando Redes de Similaridade Temporal

Autores
Fernandes Pereira, FS; Linhares, CDG; Ponciano, JR; Gama, J; Amo, Sd; Oliveira, GMB;

Publicação
Braz. J. Inf. Syst.

Abstract

2019

A Pan-cancer Transcriptome Analysis Reveals Pervasive Regulation through Alternative Promoters

Autores
Demircioglu, D; Cukuroglu, E; Kindermans, M; Nandi, T; Calabrese, C; Fonseca, NA; Kahles, A; Kjong Van Lehmann,; Stegle, O; Brazma, A; Brooks, AN; Ratsch, G; Tan, P; Goke, J;

Publicação
CELL

Abstract
Most human protein-coding genes are regulated by multiple, distinct promoters, suggesting that the choice of promoter is as important as its level of transcriptional activity. However, while a global change in transcription is recognized as a defining feature of cancer, the contribution of alternative promoters still remains largely unexplored. Here, we infer active promoters using RNA-seq data from 18,468 cancer and normal samples, demonstrating that alternative promoters are a major contributor to context-specific regulation of transcription. We find that promoters are deregulated across tissues, cancer types, and patients, affecting known cancer genes and novel candidates. For genes with independently regulated promoters, we demonstrate that promoter activity provides a more accurate predictor of patient survival than gene expression. Our study suggests that a dynamic landscape of active promoters shapes the cancer transcriptome, opening new diagnostic avenues and opportunities to further explore the interplay of regulatory mechanisms with transcriptional aberrations in cancer.

2019

ArrayExpress update - from bulk to single-cell expression data

Autores
Athar, A; Fullgrabe, A; George, N; Iqbal, H; Huerta, L; Ali, A; Snow, C; Fonseca, NA; Petryszak, R; Papatheodorou, I; Sarkans, U; Brazma, A;

Publicação
NUCLEIC ACIDS RESEARCH

Abstract
ArrayExpress (https://www.ebi.ac.uk/arrayexpress) is an archive of functional genomics data from a variety of technologies assaying functional modalities of a genome, such as gene expression or promoter occupancy. The number of experiments based on sequencing technologies, in particular RNA-seq experiments, has been increasing over the last few years and submissions of sequencing data have overtaken microarray experiments in the last 12 months. Additionally, there is a significant increase in experiments investigating single cells, rather than bulk samples, known as single-cell RNA-seq. To accommodate these trends, we have substantially changed our submission tool Annotare which, along with raw and processed data, collects all metadata necessary to interpret these experiments. Selected datasets are re-processed and loaded into our sister resource, the value-added Expression Atlas (and its component Single Cell Expression Atlas), which not only enables users to interpret the data easily but also serves as a test for data quality. With an increasing number of studies that combine different assay modalities (multi-omics experiments), a new more general archival resource the BioStudies Database has been developed, which will eventually supersede ArrayExpress. Data submissions will continue unchanged; all existing ArrayExpress data will be incorporated into BioStudies and the existing accession numbers and application programming interfaces will be maintained.

2019

Predicting Blood Donations in a Tertiary Care Center Using Time Series Forecasting

Autores
Bischoff, F; Carmo Koch, Md; Rodrigues, PP;

Publicação
ICT for Health Science Research - Proceedings of the EFMI 2019 Special Topic Conference - 7-10 April 2019, Hanover, Germany

Abstract
The current algorithm to support platelets stock management assumes that there are always sufficient whole blood donations (WBD) to produce the required amount of pooled platelets. Unfortunately, blood donation rate is uncertain so there is the need to backup pooled platelets productions with single-donor (apheresis) collections to compensate periods of low WBD. The aim of this work was to predict the daily number of WBD to a tertiary care center to preemptively account for a decrease of platelets production. We have collected 62,248 blood donations during 3 years, the daily count of which was used to feed (standalone and ensemble versions of) six prediction models, which were evaluated using the Mean Absolute Error (MAE). Forecast models have shown better performances with a MAE of about 8.6 donations, 34% better than using means or medians alone. Trend lines of donations are better modeled by autoregressive integrated moving average (ARIMA) using a frequency of 365 days, the trade-off being the need for at least two years of data.

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