A Digital Twin is a digital replica of a living or nonliving physical entity, and this emerging technology attracted extensive attention from different industries during the past decade. Although a ...few Digital Twin studies have been conducted in the transportation domain very recently, there is no systematic research with a holistic framework connecting various mobility entities together. In this study, a mobility digital twin (MDT) framework is developed, which is defined as an artificial intelligence (AI)-based data-driven cloud-edge-device framework for mobility services. This MDT consists of three building blocks in the physical space (namely, Human , Vehicle , and Traffic ), and their associated Digital Twins in the digital space. An example cloud-edge architecture is built with Amazon Web Services (AWS) to accommodate the proposed MDT framework and to fulfill its digital functionalities of storage, modeling, learning, simulation, and prediction. A case study of the personalized adaptive cruise control (P-ACC) system is conducted, which integrates the key microservices of all three digital building blocks of the MDT framework: 1) the Human Digital Twin with user management and driver type classification; 2) the Vehicle Digital Twin with cloud-based advanced driver-assistance systems (ADAS); and 3) the Traffic Digital Twin with traffic flow monitoring and variable speed limit. Future challenges of the proposed MDT framework are discussed toward the end of the article, including standardization, AI for computing, public or private cloud service, and network heterogeneity.
Currently, as shown by large-scale research on two-dimensional materials in the field of nanoelectronics and catalysis, the construction of large-area two-dimensional materials is crucial for the ...development of devices and their application in photovoltaics, sensing, optoelectronics, and energy generation/storage. Here, using atmospheric-pressure chemical vapor deposition, we developed a method to regulate growth conditions according to the growth mechanism for WSesub.2 and MoSesub.2 materials. By accurately controlling the hydrogen flux within the range of 1 sccm and the distance between the precursor and the substrate, we obtained large-size films of single atomic layers with thicknesses of only about 1 nm. When growing the samples, we could not only obtain a 100 percent proportion of samples with the same shape, but the samples could also be glued into pieces of 700 μm and above in size, changing the shape and making it possible to reach the millimeter/submillimeter level visible to the naked eye. Our method is an effective method for the growth of large-area films with universal applicability.
Service-oriented computing (SOC) represents a paradigm for building distributed computing applications over the Internet. In the past decade, Web services composition has been an active area of ...research and development endeavors for application integration and interoperation. Although Web services composition has been heavily investigated, several issues related to dependability, ubiquity, personalization, among others, still need to be addressed, especially giving the recent rise of several new computing paradigms such as Cloud computing, social computing, and Web of Things. This article overviews the life cycle of Web services composition and surveys the main standards, research prototypes, and platforms. These standards, research prototypes, and platforms are assessed using a set of assessment criteria identified in the article. The paper also outlines several research opportunities and challenges for Web services composition.
Automated composition of Web Services can be achieved by using AI planning techniques. Hierarchical Task Network (HTN) planning is especially well-suited for this task. In this paper, we describe how ...HTN planning system SHOP2 can be used with OWL-S Web Service descriptions. We provide a sound and complete algorithm to translate OWL-S service descriptions to a SHOP2 domain. We prove the correctness of the algorithm by showing the correspondence to the situation calculus semantics of OWL-S. We implemented a system that plans over sets of OWL-S descriptions using SHOP2 and then executes the resulting plans over the Web. The system is also capable of executing information-providing Web Services during the planning process. We discuss the challenges and difficulties of using planning in the information-rich and human-oriented context of Web Services.
The web service computing paradigm has introduced great benefits to the growth of e-markets, both under the customer to business and the business to business models. The value capabilities allowed by ...the conception of web services, such as interoperability, efficiency, just-in-time integration, etc., have made them the most common way of doing business online. With the maturation of the web services underlying functional properties and facilitating standards, and with the proliferation of the amounts of data they use and they generate, researchers and practitioners have been dedicating considerable efforts to the related emerging privacy concerns. The literature contains number of research works on these privacy concerns, each addressing them from a different focal point. We have explored the available literature on web services privacy during transactions, to present, in this paper, a thorough survey of the most relevant published proposals. We identified 20 works that address privacy related problems in web services consumption. We categorize them based on the approach they take and we compare them based on a proposed evaluation framework, derived from the adopted techniques and addressed requirements.
Web services promise to become a key enabling technology for B2B e-commerce. One of the most-touted features of Web services is their capability to recursively construct a Web service as a workflow ...of other existing Web services. The quality of service (QoS) of Web-services-based workflows may be an essential determinant when selecting constituent Web services and determining the service-level agreement with users. To make such a selection possible, it is essential to estimate the QoS of a WS workflow based on the QoSs of its constituent WSs. In the context of WS workflow, this estimation can be made by a method called
QoS aggregation. While most of the existing work on QoS aggregation treats the QoS as a deterministic value, we argue that due to some uncertainty related to a WS, it is more realistic to model its QoS as a random variable, and estimate the QoS of a WS workflow probabilistically. In this paper, we identify a set of QoS metrics in the context of WS workflows, and propose a unified probabilistic model for describing QoS values of a broader spectrum of atomic and composite Web services. Emulation data are used to demonstrate the efficiency and accuracy of the proposed approach.
Metamorphic Testing of RESTful Web APIs Segura, Sergio; Parejo, Jose A.; Troya, Javier ...
IEEE transactions on software engineering,
11/2018, Letnik:
44, Številka:
11
Journal Article
Recenzirano
Web Application Programming Interfaces (APIs) allow systems to interact with each other over the network. Modern Web APIs often adhere to the REST architectural style, being referred to as RESTful ...Web APIs. RESTful Web APIs are decomposed into multiple resources (e.g., a video in the YouTube API) that clients can manipulate through HTTP interactions. Testing Web APIs is critical but challenging due to the difficulty to assess the correctness of API responses, i.e., the oracle problem. Metamorphic testing alleviates the oracle problem by exploiting relations (so-called metamorphic relations) among multiple executions of the program under test. In this paper, we present a metamorphic testing approach for the detection of faults in RESTful Web APIs. We first propose six abstract relations that capture the shape of many of the metamorphic relations found in RESTful Web APIs, we call these Metamorphic Relation Output Patterns (MROPs). Each MROP can then be instantiated into one or more concrete metamorphic relations. The approach was evaluated using both automatically seeded and real faults in six subject Web APIs. Among other results, we identified 60 metamorphic relations (instances of the proposed MROPs) in the Web APIs of Spotify and YouTube. Each metamorphic relation was implemented using both random and manual test data, running over 4.7K automated tests. As a result, 11 issues were detected (3 in Spotify and 8 in YouTube), 10 of them confirmed by the API developers or reproduced by other users, supporting the effectiveness of the approach.
•Extracted features from web services and NLP is applied for preprocessing.•Proposed Length Feature Weight Method for vector form of preprocessed services.•Applied K-Mean clustering on the vector ...representation of web service documents.•Achieved better clustering performance measured using standard measurement criteria.
Due to the rapid growth of web services in repositories, discovering the requisite web service is becoming increasingly cumbersome task. It has raised the demand for efficient web service clustering algorithms. In service repositories, when related web services are stored in a clustered way, it enhances the web service discovery process by reducing search space and time. Many eminent researchers have worked in this field and used the Term Frequency – Inverse Document Frequency (TF-IDF) method for representing web services in vector space. In general, there are various limitations of the TF-IDF approach i.e. (1) Not efficient for large documents (2) Position of term and its co-occurrences does not matter (3) Unable to analyze how terms are dispersed in different documents. In the web service scenario, services are represented in short text form. TF-IDF does not work well in web service representation because of the reason that it is unable to effectively find the importance of a term concerning its occurrence in other documents. If we compare two service documents i.e. ‘s1’ and ‘s2’ first having a large and second having small number of terms respectively then TF-IDF does not demonstrate the importance of terms in ‘s1’ as smaller to ‘s2’. Therefore, it is not possible to assign effective weights to the terms. In the lack of effective vector space representation, the performance of the clustering algorithm also degrades. In this paper, we propose a new approach i.e. LFW+K which is based on Length Feature Weight (LFW) for the vectorized representation of service followed by K-Means clustering. The proposed approach helps to find the informative term from web service and assigns the term weight accordingly by considering parameters like the dimension of the web service document, maximum frequency of a term in the document and occurrences of a term in other documents. LFW+K is applied on the datasets of real-world web services and the performance is measured using standard measurement criteria (i.e. precision, recall, F1-score, and accuracy). Results of the proposed approach are compared with K-Means clustering on TF-IDF representation method i.e. TF-IDF+K. Results show that the proposed method outperforms the clustering done by using TF-IDF method for vector space representation of web services.
PDF
