Joanna Ng

An Approach for Context-Aware Service Discovery and Recommendation

Given the large amount of existing services and the diversified needs nowadays, it is time-consuming for end-users to find appropriate services. To help end-users obtain their desired services, context-aware systems provide a promising way to automatically search and recommend services using a user’s context. However, existing context-aware techniques have limited support for dynamic adaption to newly added context types (e.g., location, time and activity). Due to the diversity of user’s environment, the available context types may change over time. It is challenging to anticipate a complete set of context types while we design a context aware system. In this paper, we propose a context modeling approach which can dynamically handle various context types and values. More specifically, we use ontologies to enhance the meaning of a user’s context values and automatically indentify the relations among different context values. Based on the relations among context values, we capture the potential services which the user might need. A case study is conducted to evaluate the effectiveness of our approach. The results show that our approach can use contexts to find users’ needs and recommend their desired services with high precision and recall.

Migration of SOAP-based services to RESTful services

Web services are designed to provide rich functionality for organizations and support interoperable interactions over a network. Web services are mainly realized in two ways: 1) SOAP-based services and 2) RESTful services. For the service providers, RESTful services can improve system flexibility, scalability, and performance as compared to the SOAP-based Web services. It is equally attractive to end users as it is consume less resources (i.e., battery, processor speed, and memory). Additionally, REST-based services do not include complex standards and heterogeneous operations; and hence are easier to consume and compose as compared to SOAP-based Web services. We provide an approach to migrate SOAP-based services to RESTful services. We identify resources from a SOAP-based Web service by analyzing its service description and mapping the contained operations to resources and HTTP methods. To demonstrate the effectiveness of our approach, we conduct a case study on a set of publicly available SOAP-based Web services. The results of our case study show that our approach can achieve high accuracy of identifying RESTful services from the interfaces of SOAP-based services. Our approach can improve the performance for invoking Web services after SOAP-based services are migrated to RESTful services.

An automatic approach for ontology-driven service composition

Current service composition techniques and tools are mainly designed for use by Service Oriented Architecture (SOA) professionals to solve business problems. This focus on SOA professionals creates challenges for the non-expert users, with limited SOA knowledge, who try to integrate SOA solutions into their online experience. To shelter non-expert users from the complexity of service composition, we propose an approach which automatically composes a service on the fly to meet the situational needs of a user. We present a tag-based service description schema which allows non-expert users to easily understand the description of services and add their own descriptions using descriptive tags. Instead of specifying the detailed steps for composing a service, a non-expert user would specify the goal of their desired activities using a set of keywords then our approach can automatically identify the relevant services to achieve the goal at run-time. A prototype is developed as a proof of concept. We conduct a case study to compare the performance of our approach in automatic service composition with a baseline approach which consists of the manual process of searching for services using keywords. The case study shows that our approach can achieve higher precision and recall than the baseline approach.

The smart internet: transforming the web for the user

Key architectural elements of the web, namely, HTTP, URL and HTML enable a very simple user model of the web based on hyperlinks. While this model allows browser-based access to a wide array of online content and resources, the limitations in user experience provided in this interaction model are increasingly apparent. Two decades after the birth of the web, new technologies such as Rich Internet Application, AJAX, and Web 2.0 seek to improve web user interfaces, but in general their main benefit is to individual server sites. Little advancement has been made to advance the user model of the web at a macro level where the interaction is driven not by the server but by the user. This paper proposes a novel approach to scientific study of the Web (Web science) where the traditional relationship between users and servers is inverted, so that web services are configured and integrated across multiple servers/sites in order to address the needs of users. The resulting interaction paradigm is referred to here as smart interaction. The Smart interaction approach is quite different from the current hyperlink-oriented user model driven from the perspective of the server side. Smart interactions require new web infrastructure (e.g., runtime components) and new patterns of services and resource interactions and compositions. A Complementary area of research is smart services; where the focus is on abstracting these web infrastructures and service interaction patterns into appropriate web models and algorithms. The combination of smart interaction and smart services will then result in a smart internet where user experience is enhanced, and user productivity unleashed, by passing control back to users.

Ontology-driven service composition for end-users

Current service composition techniques and tools are mainly designed for use by Service-Oriented Architecture (SOA) professionals to solve business problems. Little attention has been paid to allowing end-users without sufficient service composition skills to compose services and integrate SOA solutions into their online experience to fulfill their daily activities. To shelter end-users from the complexity of service composition, we propose an approach which can compose services on the fly to meet the situational needs of end-users. We present a tag-based service description schema which allows non-IT professional users to easily understand the description of services and add their own descriptions using descriptive tags. Instead of requiring end-users to specify detailed steps for composition, the end-users only need to describe their goals using a few keywords. Our approach expands the meaning of a user’s goal using ontologies then derives a group of keywords to discover services in order to fulfill the goal. A prototype is developed as a proof of concept to show that our approach enables end-users to discover and compose services easily. We conduct a case study to evaluate the effectiveness of our approach that eases end-users to compose services without the knowledge of SOA technologies. The results of our case study show that our approach can effectively generate ad-hoc processes and discover services with relatively high precision and recall.

Quality of Experience: User's Perception about Web Services

Web service composition enables seamless and dynamic integration of Web services. The behavior of participant Web services determines the overall performance of a composition. Therefore, it is important to choose high quality services for service composition. Existing Web service selection and discovery approaches rely on non-functional aspects (also known as quality of service or QoS), e.g., response time and availability. Though these parameters are crucial for selecting Web services, they may not reflect the users perspective of quality. In this paper, we explore the feasibility of incorporating perceived quality from users perspective for service selection and composition. We name such quality attributes as quality of experience (QoE). First, we propose a solution that automatically mines and identifies QoE attributes from the Web. Second, we study the application of such dynamically extracted QoE attributes for service selection. For the evaluation purpose, we collected more than 34,000 reviews from 58 different services in six domains. Our findings show that it is possible to automatically identify QoE attributes with an average precision and recall of 92 and 80 percent respectively. Our study shows that there is a strong positive correlation between QoS and QoE. Hence QoE can be used during service selection especially when QoS data are not available. Furthermore, we found 70 percent of service discovery queries indeed contain QoE attributes showing the importance of QoE attributes during the service discovery phase.

An Automatic Approach for Extracting Process Knowledge from the Web

Process knowledge, such as tasks involved in a process and the control flow and data flow among tasks, is critical for designing business processes. Such process knowledge enables service composition which integrates different services to implement business processes. In the current state of practice, business processes are primarily designed by experienced business analysts who have extensive process knowledge. It is challenging for novice business analysts and non-professional end-users to identify a complete set of services to orchestrate a well-defined business process due to the lack of process knowledge. In this paper, we propose an approach to extract process knowledge from existing commercial applications on the Web. Our approach uses a Web search engine to find websites containing process knowledge on the Internet. By analyzing the content and the structure of relevant websites, we extract the process knowledge from various websites and merge the process knowledge to generate an integrated ontology with rich process knowledge. We conduct a case study to compare our approach with a tool that extracts ontologies from textual sources. The result of the case study shows that our approach can extract process knowledge from online applications with higher precision and recall comparing to the ontology learning tool.

An Exploratory Study on the Relation between User Interface Complexity and the Perceived Quality

The number of mobile applications has increased drastically in the past few years. Some applications are superior to the others in terms of user-perceived quality. User-perceived quality can be defined as the user’s opinion of a product. For mobile applications, it can be quantified by the number of downloads and ratings. Earlier studies suggested that user interface (UI) barriers (i.e., input or output challenges) can affect the user-perceived quality of mobile applications. In this paper, we explore the relation between UI complexity and user-perceived quality in Android applications. Furthermore, we strive to provide guidelines for the proper amount of UI complexity that helps an application achieve high user-perceived quality through an empirical study on 1,292 mobile applications in 8 different categories.

Automatically Composing Services by Mining Process Knowledge from the Web

Current approaches in Service-Oriented Architecture SOA are challenging for users to get involved in the service composition due to the in-depth knowledge required for SOA standards and techniques. To shield users from the complexity of SOA standards, we automatically generate composed services for end-users using process knowledge available in the Web. Our approach uses natural language processing techniques to extract tasks. Our approach automatically identifies services required to accomplish the tasks. We represent the extracted tasks in a task model to find the services and then generate a user interface UI for a user to perform the tasks. Our case study shows that our approach can extract the tasks from how-to instructions Web pages with high precision i.e., 90%. The generated task model helps to discover services and compose the found services to perform a task. Our case study shows that our approach can reach more than 90% accuracy in service composition by identifying accurate data flow relation between services.

Quality of Experience: What End-Users Say about Web Services?

Web service composition enables seamless and dynamic integration of web services. The behavior of participant web services determines the overall performance of a composition. Therefore, it is important to choose the high quality participants for service composition. The state of the art in service discovery and selection rely on non-functional aspects also known as quality of service (QoS) e.g., response time and availability. Though these parameters are crucial for selecting web services, they do not reflect the end-users perspective on quality. In this paper, we explore the feasibility of adopting the perceived quality from end-users perspective for service selection and composition. We name such quality parameters as quality of experience (QoE). First, we propose a solution that automatically mines and identifies QoE parameters from the web. Second, we study the application of such dynamically extracted QoE attributes for service selection. For the evaluation purpose, we collected more than 24,000 reviews from 22 different services from four domains. Our result shows the automated approach identifies QoE attributes with an average precision and recall 90% and 79% respectively. Our study shows that there is a strong positive correlation between QoS and QoE. Hence QoE can be used during service selection especially when QoS data are not available.