Quality Of Service Prediction Approach Research Articles

Accurately Predicting Quality of Services in IoT via Using Self-Attention Representation and Deep Factorization Machines

The past decade has witnessed a widespread adoption of IoT devices and services in various applications such as intelligent transportation systems. It is crucial for IoT applications to select high-quality services to boost their reliability and efficiency. The prediction for Quality of Service (QoS) can be used to address this issue. Although a number of QoS prediction approaches have been proposed, their performance may be limited in the IoT environment where context features can significantly impact QoS predictions. Based on the historical QoS records of services, this paper proposes a collaborative QoS prediction approach using self-attention representation and deep factorization machine. The approach first leverages the global and local contextual information of services and users to learn personalized representations. Then, based on the personalized representations, it utilizes a deep factorization machine to make QoS predictions. Extensive experiments conducted on a real-world dataset show that the proposed QoS prediction approach significantly outperforms the other state-of-the-art approaches in terms of prediction accuracy.

Time-Aware Smart City Services Based on QoS Prediction: A Contrastive Learning Approach

Smart cities are designed to satisfy the needs of residents and improve their quality of life by providing a wide range of smart city services. The key to the efficient operation of smart city services is accurate forecast of the missing QoS (Quality of Service).. At present, many approaches utilize the context information of users and services, such as geographic location and network location, to somewhat increase the prediction accuracy and forecast the missing QoS values.. However, because the network conditions and server status are unpredictable, time is also considered as one of the important factors affecting QoS prediction, which brings more challenges as follows: higher data dimension, more complex data characteristics and higher data sparsity. To overcome these challenges,z we suggest an approach for time-aware Web service QoS prediction based on contrastive learning(named CLpred). CLpred utilizes a sequential data input format for QoS data and models these QoS sequences through Transformer encoder with contrastive learning framework. Therefore, it can downscale QoS data and extract a more efficient representation in complex QoS data. Furthermore, it makes it possible to apply data augmentation methods to address these probelms of data sparsity. In order to prove the superiority of the this approach, particularly inside the presence of extremely high data sparsity, extensive tests are carried out on the well-known service QoS data set WSDREAM.

A QoS Prediction Approach Based on Truncated Nuclear Norm Low-Rank Tensor Completion.

With the rise of mobile edge computing (MEC), mobile services with the same or similar functions are gradually increasing. Usually, Quality of Service (QoS) has become an indicator to measure high-quality services. In the real MEC service invocation environment, due to time and network instability factors, users’ QoS data feedback results are limited. Therefore, effectively predicting the Qos value to provide users with high-quality services has become a key issue. In this paper, we propose a truncated nuclear norm Low-rank Tensor Completion method for the QoS data prediction. This method represents complex multivariate QoS data by constructing tensors. Furthermore, the truncated nuclear norm is introduced in the QoS data tensor completion in order to mine the correlation between QoS data and improve the prediction accuracy. At the same time, the general rate parameter is introduced to control the truncation degree of tensor mode. Finally, the prediction approximate tensor is obtained by the Alternating Direction Multiplier Method iterative optimization algorithm. Numerical experiments are conducted based on the public QoS dataset WS-Dream. The results indicate that our QoS prediction method has better prediction accuracy than other methods under different missing density QoS data.

Web Service QoS Prediction via Collaborative Filtering: A Survey

With the growing number of competing Web services that provide similar functionality, Quality-of-Service (QoS) prediction is becoming increasingly important for various QoS-aware approaches of Web services. Collaborative filtering (CF), which is among the most successful personalized prediction techniques for recommender systems, has been widely applied to Web service QoS prediction. In addition to using conventional CF techniques, a number of studies extend the CF approach by incorporating additional information about services and users, such as location, time, and other contextual information from the service invocations. There are also some studies that address other challenges in QoS prediction, such as adaptability, credibility, privacy preservation, and so on. In this survey, we summarize and analyze the state-of-the-art CF QoS prediction approaches of Web services and discuss their features and differences. We also present several Web service QoS datasets that have been used as benchmarks for evaluating the predition accuracy and outline some possible future research directions.

HSA-Net: Hidden-State-Aware Networks for High-Precision QoS Prediction

The high-precision QoS (quality of service) prediction is based on the comprehensive perception of state information of users and services. However, the current QoS prediction approaches have limited accuracy, for most state information of users and services (i.e., network speed, latency, network type, and more) are hidden due to privacy protection. Therefore, this article proposes a hidden-state-aware network (HSA-Net) that includes three steps called hidden state initialization, hidden state perception, and QoS prediction. A hidden state initialization approach is developed first based on the latent dirichlet allocation (LDA). After that, a hidden-state perception approach is proposed to abstract the initialized hidden state by fusing the known information (e.g., service ID and user location). The perception approach consists of four hidden-state perception (HSP) modes (i.e., known mode, object mode, hybrid mode and overall mode) implemented to generate explainable and fused features through four adaptive convolutional kernels. Finally, the relationship between the fused features and the QoS is discovered through a fully connected network to complete the high-precision QoS prediction process. The proposed HSA-Net is evaluated on two real-world datasets. According to the results, the HSA-Net's mean absolute error (MAE) index reduced by 3.67% and 28.84%, whereas the root mean squared error (RMSE) index decreased by 3.07% and 7.14% compared with ten baselines on average in the two datasets.

A truncated SVD-based ARIMA model for multiple QoS prediction in mobile edge computing

In the mobile edge computing environments, Quality of Service (QoS) prediction plays a crucial role in web service recommendation. Because of distinct features of mobile edge computing, i.e., the mobility of users and incomplete historical QoS data, traditional QoS prediction approaches may obtain less accurate results in the mobile edge computing environments. In this paper, we treat the historical QoS values at different time slots as a temporal sequence of QoS matrices. By incorporating the compressed matrices extracted from QoS matrices through truncated Singular Value Decomposition (SVD) with the classical ARIMA model, we extend the ARIMA model to predict multiple QoS values simultaneously and efficiently. Experimental results show that our proposed approach outperforms the other state-of-the-art approaches in accuracy and efficiency.

HAP: A Hybrid QoS Prediction Approach in Cloud Manufacturing Combining Local Collaborative Filtering and Global Case-Based Reasoning

With the rapid development of cloud manufacturing (CMfg), a large number of functionally equivalent cloud services are available on the Internet, thus quality of service (QoS) prediction has become a hot issue. Since the QoS of service varies widely among users, many Collaborative Filtering (CF) approaches are recently proposed to predict the unknown QoS by extending the Pearson Correlation Coefficient (PCC) similarity. However, most existing approaches either enhance the similarity computation inadequately or ignore the data sparsity problem, and are thus vulnerable to the unreliable result. To address this problem, we propose a hybrid approach HAP for QoS prediction. First, to achieve high prediction accuracy, we employ a similarity-enhanced CF (L-CF) for local QoS prediction, in which the personalized influence of similar users and services are considered when computing PCC similarity. Second, to overcome the data sparsity problem, we propose a global QoS prediction approach based on the case-based reasoning (G-CBR) which could make full use of both user and service information. Finally, we establish an ensemble model to combine the results of two approaches. Comprehensive real-world experiments are conducted to demonstrate the effectiveness of our approach compared with other state-of-the-arts approaches, particularly when the QoS data is very sparse.

Context and auto-interaction are all you need: Towards context embedding based QoS prediction via automatic feature interaction for high quality cloud API delivery

Cloud application programming interface (API) is a software intermediary that enables data exchange, business logic or functionality delivery between applications, infrastructures and IoT devices for supporting service oriented architecture. Currently, the number of cloud API in the Web is increasing and the number of cloud API with similar functionality is very large. Since quality of service (QoS) can well differentiate the performance of similar cloud API, QoS prediction has become the critical base for fast, personalized and high-quality cloud API selection and recommendation. However, contexts are used indirectly through context aware neighbors in most existing researches and the combined feature interactions are treated equally in previous factorization machine based methods, which together hinder the accurate QoS prediction. To address the above concerns, we first conduct data analysis on real-world QoS datasets and provide conclusive evidence to verify the necessity of incorporating contextual information and differentiating feature interaction. Then, we propose a context-aware QoS prediction approach via automatic feature interaction named CAFI. Contextual information of both user and cloud API sides are directly fed into CAFI through feature embedding. Moreover, the importance weights of feature interactions are learned by a generalized regularized dual averaging optimizer, so as to reward effective feature interaction and penalize noise feature interaction automatically. Lastly, final QoS prediction is obtained in an ensemble way by balancing the results of linear regression, automatic feature interaction and non-linear interaction. Extensive experiments on two public real-world QoS datasets demonstrate that CAFI can significantly improve QoS prediction accuracy. And the proposed CAFI approach is promising to encourage service providers provide high quality APIs and enable developer get desired cloud APIs quickly, thereby promoting the development of API economy.

A graph-based QoS prediction approach for web service recommendation

With the development of the Internet, the recommendation based on Quality of Service(QoS) is proven to be an efficient way to deal with the ever-increasing web services in both industry and academia. However, it is hard to make an accurate recommendation using sparse QoS data, which makes QoS prediction a growing concern in the context of web service recommendation. In this research, a novel Graph-based Matrix Factorization approach(GMF) is proposed for QoS prediction. First, a concept of integrated-graph is put forward to consolidate multi-source information from user–aware context and service-aware context, and to deep mine potential relationships based on QoS matrix. Furthermore, the integrated-graph is divided into several sub-graphs by cutting insignificant edges to reduce noises and strengthen interactions between users and services. Based on the local information of each sub-graph and the global information of integrated-graph, a Gaussian Mixture Model(GMM) of QoS value is built as a fusion method to combine local and global information adaptively and to complete final QoS prediction. The extensive experimental analysis on a publicly available dataset indicate that our graph-based method is both accurate and practical.

A QoS Prediction Approach Based on Fusion of Network Representation Learning and Dynamic Collaborative Filtering for Cloud Service

In recent years, the number of cloud services has increased dramatically with the development of internet technology. The recommendation of cloud service based on quality of service (QoS) has received more and more attention. The traditional matrix decomposition model has cold start and matrix sparse problems, which cannot fully describe the relationship between users and services, thus affecting the effect of QoS value prediction. In order to accurately predict the QoS value of missing cloud services, this paper proposes a prediction method of fusion network representation learning and dynamic collaborative filtering. The method can better mine the high-dimensional relationship vector of the user-service-attribute ternary network feature through network representation learning. The high-dimensional relation vector learned by the network representation is integrated into the dynamic collaborative filtering algorithm to solve the problem of sparse QoS matrix data in the dynamic collaborative filtering method. The effectiveness of the proposed method is verified by experimental simulation.

A QoS prediction approach based on fusion of network representation learning and dynamic collaborative filtering for cloud service

In recent years, the number of cloud services has increased dramatically with the development of internet technology. The recommendation of cloud service based on quality of service (QoS) has received more and more attention. The traditional matrix decomposition model has cold start and matrix sparse problems, which cannot fully describe the relationship between users and services, thus affecting the effect of QoS value prediction. In order to accurately predict the QoS value of missing cloud services, this paper proposes a prediction method of fusion network representation learning and dynamic collaborative filtering. The method can better mine the high-dimensional relationship vector of the user-service-attribute ternary network feature through network representation learning. The high-dimensional relation vector learned by the network representation is integrated into the dynamic collaborative filtering algorithm to solve the problem of sparse QoS matrix data in the dynamic collaborative filtering method. The effectiveness of the proposed method is verified by experimental simulation.

NDMF: Neighborhood-Integrated Deep Matrix Factorization for Service QoS Prediction

Quality of service (QoS) has been mostly applied to represent non-functional properties of Web services and differentiate those with the same functionality. How to accurately predict service QoS has become a key research topic. Researchers have employed neighborhood information into matrix factorization (MF) for service QoS prediction in recent years. However, they are restricted to traditional matrix factorization that may incur a couple of limitations. 1) Conventional MF for QoS prediction linearly combines the multiplication of the latent feature representation of users and services through inner product, failing to fully capture the implicit features of user and service. 2) Most of approaches integrate user or service neighborhood as heuristics into MF model, where either location context or historical invocation records are used to calculate similar users or services. Nevertheless, combining both of them together in a collaborative way is ignored for neighborhood selection that has yet to be properly explored. To deal with the challenges, we propose a novel approach for service QoS prediction called ${N}$ eighborhood-integrated ${D}$ eep ${M}$ atrix ${F}$ actorization (NDMF), which integrates user neighborhood selected by a collaborative way into an enhanced matrix factorization model via deep neural network (DNN). We implement a prototype system and conduct extensive experiments on public and real-world large Web service dataset with almost 2,000,000 service invocations called WS-DREAM which is widely used in service QoS prediction. The experimental results demonstrate that our proposed approach significantly outperforms state-of-the-art ones in terms of multiple evaluation metrics.

A probability distribution detection based hybrid ensemble QoS prediction approach

Recently, with the rapid increase in the number of web services, how to discover services to meet personalized requirements of users in large-scale scenarios has become a popular topic in both industry and academia. The quality of service (QoS) prediction-based web service recommendation system has been widely studied as an effective method for solving this problem. However, due to the sparsity and imbalance of the observed QoS data, existing QoS prediction approaches suffer from limited prediction accuracy and poor scalability. Moreover, existing QoS prediction approaches do not consider the probability distribution of the observed QoS data, which have remarkable impacts on the prediction performance. In this paper, we propose a novel probability distribution detection-based hybrid ensemble QoS prediction model that can dynamically integrate a set of basic prediction models to improve the prediction accuracy instead of designing complex and time-consuming models. Specifically, we first propose an enhanced CF (collaborative filtering)-based approach as the basis of the prediction model. Second, given the results of a set of other basic prediction models, in addition, we propose a distribution detection algorithm to calculate the PCWs (probability confidence weights) of those results. Finally, we combine them dynamically to obtain final results based on PCWs. Experiments based on real datasets show that our approach has higher prediction accuracy and better scalability than existing mainstream QoS prediction approaches.

Neighborhood-aware web service quality prediction using deep learning

With the rapid growth of web services on the Internet, it becomes more difficult for users who want to choose the high-quality web services from a large number of functionally equivalent candidate services. Therefore, the prediction of quality of service (QoS) values according to the history of web services has received extensive attention. In recent years, deep learning has achieved great success in speech recognition, image processing, and natural language understanding. However, it is rarely applied to the service recommendation field. Therefore, a novel approach for QoS prediction named NDL (neighborhood-aware deep learning) is proposed. NDL first gets the Top-k neighbors of the user and the service through the Pearson correlation coefficient according to the service QoS information. Then, it extracts the potential features of the user neighbor and the service neighbor; after that, it inputs the QoS values of the user and the user neighbor as well as the QoS values of the service and service neighbors as a convolutional neural network. The results of experiments conducted on a real-world dataset demonstrate that the NDL significantly outperforms the current QoS prediction method in prediction accuracy.

Context-aware composite SaaS using feature model

Abstract Software as a Service (SaaS) in cloud computing is delivered in a composite form to effectively address complex levels of user’s requirements. Composite SaaS runs in a dynamic distributed cloud environment where the quality of service (QoS) properties of the constituents may get violated at runtime. To face such dynamism and volatility, it is vital to support an online adaptation of composite SaaS. Recent research focused on centralized adaptation approaches based on the closed world assumption that the boundary between SaaS and the cloud environment is known. This is impractical for dynamic composition that requires distributed settings in the open world. To address these challenges, this paper proposes a distributed approach for composite SaaS adaptation applying the master/slave pattern. Slaves locally monitor and adapt the distributed SaaS constituents and send performance information to the master, which adapts the composite service to provide the global expected QoS and monitors the overall performance. To support dynamic adaptation by the master, we propose a solution based on the feature model that captures the variability of the composite SaaS. The activation and deactivation of nodes in the feature model reconfigure the workflow of the composition. Since the reconfiguration task is complex, we apply a meta-heuristic search technique to solve this problem while minimizing the adaptation cost (i.e., resource consumption and violation penalties). Furthermore, we propose an adaption approach for SaaS constituents that substitutes the failed ones promptly to avoid costly global SLA violations. Finally, we present a Kalman-based on-line QoS prediction approach for making decisions regarding the adaptation actions to be taken. Experimental results show that our approach is efficient in distributed and large-scale cloud environments compared to the centralized and off-line approaches.

A personalized clustering-based and reliable trust-aware QoS prediction approach for cloud service recommendation in cloud manufacturing

With the growing popularity of cloud manufacturing (CMfg), an increasing number of functionally equivalent cloud services are available on the Internet, which makes cloud service recommendation an important topic recently. Since the quality-of-service (QoS) varies largely in cloud environment, many Collaborative Filtering (CF) approaches are recently proposed to predict the uncertain QoS by utilizing the historical QoS records of similar users. In addition to the data sparsity problem, however, most existing approaches also ignore the task similarity among different users, while dissimilar tasks requested by similar users may lead to quite different QoS prediction results, and thus cannot achieve higher prediction accuracy and recommendation quality. To address this problem, we develop a novel clustering-based and trust-aware approach. Firstly, a set of similar users can be identified from the view of task similarity using clustering-based algorithm, where task similarity can be computed by incorporating both explicit textual information and rating information as well as implicit context information. Secondly, considering the fact that the QoS values may be contributed by unreliable users, we design a trust-aware CF approach by merging local and global trust values, to reconstruct trust network of the clustered users. Finally, we combine the clustering-based algorithm and trust-aware approach to make a more personalized QoS prediction and reliable cloud service recommendation for the active user in CMfg. Experimental results on two real-world data sets demonstrate the effectiveness of the proposed approach compared with other state-of-the-art approaches.

Multi-Dimensional QoS Prediction for Service Recommendations

Advances in mobile Internet technology have enabled the clients of Web services to be able to keep their service sessions alive while they are on the move. Since the services consumed by a mobile client may be different over time due to client location changes, a multi-dimensional spatiotemporal model is necessary for analyzing the service consumption relations. Moreover, competitive Web service recommenders for the mobile clients must be able to predict unknown quality-of-service (QoS) values well by taking into account the target client's service requesting time and location, e.g., performing the prediction via a set of multi-dimensional QoS measures. Most contemporary QoS prediction methods exploit the QoS characteristics for one specific dimension, e.g., time or location, and do not exploit the structural relationships among the multi-dimensional QoS data. This paper proposes an integrated QoS prediction approach which unifies the modeling of multi-dimensional QoS data via multi-linear-algebra based concepts of tensor and enables efficient Web service recommendation for mobile clients via tensor decomposition and reconstruction optimization algorithms. In light of the unavailability of measured multi-dimensional QoS datasets in the public domain, this paper also presents a transformational approach to creating a credible multi-dimensional QoS dataset from a measured taxi usage dataset which contains high dimensional time and space information. Comparative experimental evaluation results show that the proposed QoS prediction approach can result in much better accuracy in recommending Web services than several other representative ones.

Predicting Quality of Service via Leveraging Location Information

QoS (Quality of Service) (our approach can be applied to a wide variety of services; in this paper, we focus on Web services) performance is intensively relevant to locations due to the network distance and the Internet connection between users and services. Thus, considering the location information of services and users is necessary. However, the location information has been ignored by most previous work. In this paper, we take both services’ and users’ location information into account. Specifically, we propose a location‐aware QoS prediction approach, called LANFM, by exploiting neural network techniques and factorization machine to improve user‐perceived experience. First of all, the information (e.g., id and location) of services and users is expressed as embedding vectors by leveraging neural network techniques. Then, the inner product of various embedding vectors, along with the weighted sum of feature vectors, is used to predict the QoS values. It should be noted that the inner product operation could capture the interactions between services and users, which is helpful to predict QoS values of services that have not been invoked by users. A collection of extensive experiments have been carried out on a real‐world dataset to validate the effectiveness of the LANFM model.

A Factorization Machine-Based QoS Prediction Approach for Mobile Service Selection

Mobile services allow us to access the abundant and various resources (including data and services) on the Internet or devices in the physical world via wireless network technologies. It becomes increasingly popular to create mobile applications by combining existing mobile services. Mobile service selection is an important issue since different services with equivalent functions may have quite different qualities (e.g., performance). Even the same service may present different performances due to the volatility of mobile environments and move of users. Hence, getting aware of the quality of mobile services is a crucial need in service selection. To meet this need, a dozen of quality-of-service (QoS) prediction approaches have been proposed for traditional Web services and mobile services. However, their prediction accuracy and time efficiency still have plenty of room for improvement. This paper proposes a collaborative filtering approach to predict the QoS of mobile services based on factorization machines. Factorization machines significantly improve the traditional collaborative filtering techniques in both accuracy and time efficiency. The proposed approach revamps the classic factorization machine model by incorporating the locations of service users to better fit the mobile environments. The experimental results based on real-world QoS data show that the proposed approach outperforms the other collaborative filtering approaches.

A Personalized QoS Prediction Approach for CPS Service Recommendation Based on Reputation and Location-Aware Collaborative Filtering.

With the rapid development of cyber-physical systems (CPS), building cyber-physical systems with high quality of service (QoS) has become an urgent requirement in both academia and industry. During the procedure of building Cyber-physical systems, it has been found that a large number of functionally equivalent services exist, so it becomes an urgent task to recommend suitable services from the large number of services available in CPS. However, since it is time-consuming, and even impractical, for a single user to invoke all of the services in CPS to experience their QoS, a robust QoS prediction method is needed to predict unknown QoS values. A commonly used method in QoS prediction is collaborative filtering, however, it is hard to deal with the data sparsity and cold start problem, and meanwhile most of the existing methods ignore the data credibility issue. Thence, in order to solve both of these challenging problems, in this paper, we design a framework of QoS prediction for CPS services, and propose a personalized QoS prediction approach based on reputation and location-aware collaborative filtering. Our approach first calculates the reputation of users by using the Dirichlet probability distribution, so as to identify untrusted users and process their unreliable data, and then it digs out the geographic neighborhood in three levels to improve the similarity calculation of users and services. Finally, the data from geographical neighbors of users and services are fused to predict the unknown QoS values. The experiments using real datasets show that our proposed approach outperforms other existing methods in terms of accuracy, efficiency, and robustness.