128 research outputs found
Outlier-Resilient Web Service QoS Prediction
The proliferation of Web services makes it difficult for users to select the
most appropriate one among numerous functionally identical or similar service
candidates. Quality-of-Service (QoS) describes the non-functional
characteristics of Web services, and it has become the key differentiator for
service selection. However, users cannot invoke all Web services to obtain the
corresponding QoS values due to high time cost and huge resource overhead.
Thus, it is essential to predict unknown QoS values. Although various QoS
prediction methods have been proposed, few of them have taken outliers into
consideration, which may dramatically degrade the prediction performance. To
overcome this limitation, we propose an outlier-resilient QoS prediction method
in this paper. Our method utilizes Cauchy loss to measure the discrepancy
between the observed QoS values and the predicted ones. Owing to the robustness
of Cauchy loss, our method is resilient to outliers. We further extend our
method to provide time-aware QoS prediction results by taking the temporal
information into consideration. Finally, we conduct extensive experiments on
both static and dynamic datasets. The results demonstrate that our method is
able to achieve better performance than state-of-the-art baseline methods.Comment: 12 pages, to appear at the Web Conference (WWW) 202
TPMCF: Temporal QoS Prediction using Multi-Source Collaborative Features
Recently, with the rapid deployment of service APIs, personalized service
recommendations have played a paramount role in the growth of the e-commerce
industry. Quality-of-Service (QoS) parameters determining the service
performance, often used for recommendation, fluctuate over time. Thus, the QoS
prediction is essential to identify a suitable service among functionally
equivalent services over time. The contemporary temporal QoS prediction methods
hardly achieved the desired accuracy due to various limitations, such as the
inability to handle data sparsity and outliers and capture higher-order
temporal relationships among user-service interactions. Even though some recent
recurrent neural-network-based architectures can model temporal relationships
among QoS data, prediction accuracy degrades due to the absence of other
features (e.g., collaborative features) to comprehend the relationship among
the user-service interactions. This paper addresses the above challenges and
proposes a scalable strategy for Temporal QoS Prediction using Multi-source
Collaborative-Features (TPMCF), achieving high prediction accuracy and faster
responsiveness. TPMCF combines the collaborative-features of users/services by
exploiting user-service relationship with the spatio-temporal auto-extracted
features by employing graph convolution and transformer encoder with multi-head
self-attention. We validated our proposed method on WS-DREAM-2 datasets.
Extensive experiments showed TPMCF outperformed major state-of-the-art
approaches regarding prediction accuracy while ensuring high scalability and
reasonably faster responsiveness.Comment: 10 Pages, 7 figure
Large-scale Dynamic Network Representation via Tensor Ring Decomposition
Large-scale Dynamic Networks (LDNs) are becoming increasingly important in
the Internet age, yet the dynamic nature of these networks captures the
evolution of the network structure and how edge weights change over time,
posing unique challenges for data analysis and modeling. A Latent Factorization
of Tensors (LFT) model facilitates efficient representation learning for a LDN.
But the existing LFT models are almost based on Canonical Polyadic
Factorization (CPF). Therefore, this work proposes a model based on Tensor Ring
(TR) decomposition for efficient representation learning for a LDN.
Specifically, we incorporate the principle of single latent factor-dependent,
non-negative, and multiplicative update (SLF-NMU) into the TR decomposition
model, and analyze the particular bias form of TR decomposition. Experimental
studies on two real LDNs demonstrate that the propose method achieves higher
accuracy than existing models
Estimation of Web Proxy Response Times in Community Networks Using Matrix Factorization Algorithms
Producción CientÃficaIn community networks, users access the web using a proxy selected from a list, normally without regard to its performance. Knowing which proxies offer good response times for each client would improve the user experience when navigating, but would involve intensive probing that would in turn cause performance degradation of both proxies and the network. This paper explores the feasibility of estimating the response times for each client/proxy pair by probing only a few of the existing pairs and then using matrix factorization. To do so, response times are collected in a community network emulated on a testbed platform, then a small part of these measurements are used to estimate the remaining ones through matrix factorization. Several algorithms are tested; one of them achieves estimation accuracy with low computational cost, which renders its use feasible in real networks.Ministerio de Ciencia, Innovación y Universidades - Fondo Europeo de Desarrollo Regional (grants TIN2017-85179-C3-2-R and TIN2016-77836-C2-2-R)Generalitat de Catalunya (contract AGAUR SGR 990
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