Weichang Du

University of New Brunswick · Faculty of Computer Science

We propose a temporal latent space model for user community prediction in social networks, whose goal is to predict future emerging user communities based on past history of users’ topics of interest. Our model assumes that each user lies within an unobserved latent space, and similar users in the latent space representation are more likely to be m...

Identifying and extracting user communities is an important step towards understanding social network dynamics from a macro perspective. For this reason, the work in this paper explores various aspects related to the identification of user communities. To date, user community detection methods employ either explicit links between users (link analys...

The growth in the number of publicly available services on the Web has encouraged developers to rely more heavily on such services to deliver products in a faster, cheaper and more reliable fashion. Many developers are now using a collection of these services in tandem to build their applications. While there has been much attention to the area of...

The large number of published services has motivated the development of tools for creating customized composite services known as service compositions. While service compositions provide high agility and development flexibility, they can also pose challenges when it comes to delivering guaranteed functional and non-functional requirements. This is...

Semantic search has emerged as a possible way for addressing the challenges of traditional keyword-based retrieval systems such as the vocabulary gap between the query and document spaces. In this paper, we propose a novel semantic retrieval framework that uses semantic entity linking systems for forming a graph representation of documents and quer...

We propose a neural embedding approach to identify temporally like-minded user communities, i.e., those communities of users who have similar temporal alignment in their topics of interest. Like-minded user communities in social networks are usually identified by either considering explicit structural connections between users (link analysis), user...

The composition of the functionality of multiple services into a single unique service mashup has received wide interest in the recent years. Given the distributed nature of these mashups where the constituent services can be located on different servers, it is possible that a change in the functionality or availability of a constituent service res...

Software product line engineering is a discipline that facilitates a systematic reuse-based approach by formally representing commonalities and variabilities between the applications of a target domain. As one of the main artifacts of the software product line, a feature model represents the possible configuration space and can be customized based...

User communities in social networks are usually identified by considering explicit structural social connections between users. While such communities can reveal important information about their members such as family or friendship ties and geographical proximity, just to name a few, they do not necessarily succeed at pulling like-minded users tha...

Runtime adaptive systems are able to dynamically transform their internal structure, and hence their behavior, in response to internal or external changes. Such transformations provide the basis for new functionalities or improvements of the non-functional properties that match operational requirements and standards. Software Product Line Engineeri...

The growing number of online resources, including data and services, has motivated both researchers and practitioners to provide methods and tools for non-expert end-users to create desirable applications by putting these resources together leading to the so called mashups. In this paper, we focus on a class of mashups referred to as service mashup...

This paper tackles the problem of detecting temporal content-based user communities from Twitter. Most existing content-based community detection methods consider the users who share similar topical interests to be like-minded and use this as a basis to group the users. However, such approaches overlook the potential temporality of users’ interests...

In software product line engineering, a feature model represents the possible configuration space and can be customized based on the stakeholders' needs. Considering the complexity of feature models in addition to the diversity of the stake-holders' expectations, the configuration process is viewed as a complex optimization problem. In this paper,...

Nowadays, ontologies are widely used in different research areas. Ontology mapping or ontology matching aims at finding correspondences among different ontologies The Ontology Alignment Evaluation Initiative (OAEI) is an international coordinated initiative that organizes evaluation of the increasing number of ontology matching systems. This campai...

User communities in social networks are usually identified by considering explicit structural social connections between users. While such communities can reveal important information about their members such as family or friendship ties and geographical proximity, they do not necessarily succeed at pulling like-minded users that share the same int...

Software Product Line (SPL) engineering is a systematic reuse-based software development approach which is founded on the idea of building software products using a set of core assets rather than developing individual software systems from scratch. Feature models are among the widely used artefacts for SPL development that mostly capture functional...

The Software Product Line (SPL) paradigm promotes systematic reuse-based software development and is founded on the idea of capturing commonalities and variabilities between software products of a target domain. Feature model as the main artefact of SPL development mostly captures functional and operational variability of a system. Researchers have...

Software Product Line (SPL) engineering promotes the systematic and large-scale reuse of design and implementation artifacts. Feature models are one of the main artefact of SPLE approach which essentially characterize the similar and variant functional and operational specifications of the product family. Given the complexity of the variabilities r...

In this paper, the Personal Health Service Framework (PHSF) is proposed which is an open architecture for developing patient-centric health applications and monitoring systems. PHSF uses new advancements of service-oriented architec- ture to provide a baseline for developing health-related systems. PHSF services are used to make self-monitoring and...

Nowadays, Internet has been one of the major advertising channels and behavioral targeting has become increasingly important for improving the click-through rate of online advertisements. One of the key research problems in behavioral targeting is how to group users into segments with similar interests or backgrounds. In this paper, we propose a we...

Ontologies, which are formal representations of knowledge within a domain, can be used for designing and sharing conceptual models of enterprises information for the purpose of enhancing understanding, communication and interoperability. For representing a body of knowledge, different ontologies may be designed. Recently, designing ontologies in a...

This paper proposes a novel service-oriented mobile social networking platform called MS2A for disaster situations. MS2A consists of two layers: service layer and application layer. The service layer is implemented based on the service-oriented architecture (SOA) to ease application developments. By extending and composing the web services at this...

Consequence-based reasoners are typically significantly faster than tableau-based reasoners for ontology classification. However, for more expressive DL languages like ALCHO, consequence-based reasoners are not applicable, but tableau-based reasoners can sometimes require an unacceptably long time for large and complex ontologies. This paper presen...

Consequence-based techniques have been developed to provide efficient classification for less expressive languages. Ontology transformation techniques are often used to approximate axioms in a more expressive language by axioms in a less expressive language. In this paper, we present an approach to use a fast consequence-based ALCH reasoner to clas...

In the ontology classification task, consequence-based reasoners are typically significantly faster while tableau-based reasoners can process more ex-pressive DL languages. However, both of them have difficulty to classify some available large and complex ALCHOI ontologies with complete results in ac-ceptable time. We present a prototype hybrid rea...

In order to effectively maintain mobile application services in spite of sudden network disruption, middleware services with context aware intelligent decisions are required on the mobile device and the Mobile Intelligent Server (MIS) located between mobile devices and servers. Middleware services provide the management of mobile services, network...

The necessity of dealing with uncertain knowledge has arisen from Semantic Web applications in different areas. Handling uncertainty thus becomes one of the key research directions in the Semantic Web community. This paper introduces a fuzzy logic based approach which extends the classic Description Logic with Zadeh semantics to deal with uncertain...

This paper proposes a multi-agent framework to support applications development of ambient systems. In the programming model of the framework, ambient systems can be developed by collaboration of mobile agents and service (or resident) agents, where resident agents provide application services on devices and mobile agents provide communication serv...

This paper proposes an agent based framework to incorporating distributed semantics and reasoning into a conventional distributed system, to support intelligent decisions and behaviours of distributed nodes of the system. In the framework, service agents which reside in distributed nodes provide semantic services specific to the local environment,...

To provide effective mobile services in spite of network disruption, context aware middleware services on mobile devices and application servers can provide services for continuation of applications, by managing mobile services, network connection, limited resources, and context information. In this paper, we propose context aware middleware servic...

Ontology classification is an essential reasoning task for ontology based systems. Tableau and resolution are two dominant types of reasoning procedures for ontology reasoning. Complex ontologies are often built on more expressive description logics and are usually highly cyclic. When reasoning complex ontologies, the both approaches may have diffi...

This paper introduces an open collaboration framework called SAVOIR, which supports collaboration for distributed groups to work together with open sets of heterogeneous resources. This framework is built on the concept of service computing and cloud computing with focus on the openness and accessibility. The set of resources managed in this framew...

The development of monolithic ontologies for complex domains may face various challenges in reasoning and implementation. The notion of modularity can be employed for developing more efficient ontologies, especially in distributed environments. In this paper, we introduce a framework for developing ontologies in a modular manner. We describe the in...

Harold.Boley AT nrc.gc.ca Uncertainty is an intrinsic feature of our knowledge, which is also reflected by the World Wide World and the Semantic Web. Motivated by Web applications, this paper introduces an expressive fuzzy description logic that extends classical description logics to many-valued logics. The syntax to represent imprecise or vague k...

In this paper, we present a set of semantic metrics for measuring cohesion and coupling in modular ontologies. For defining these metrics, we consider the semantic of modular ontologies instead of their syntax. Based on the semantic-based definitions, both explicitly asserted knowledge and the implied knowledge that is derived from the explicitly r...

Mobile services are prone to failures caused by the disruption of an active wireless access network connection due to the user’s movement to other networks or signal blocking (shadowing). Thus, proper mechanisms for disconnection tolerant mobile application services are needed. In this paper, we propose a middleware framework that transparently per...

In automated test generation, granting control to test experts over test selection can enhance quality of gen- erated test suites. However, in many cases test experts' control is limited and they can not dene custom cover- age criteria. This work proposes a general framework for application of knowledge engineering to software testing, which facili...

This paper has its motivation in the occurrence of uncertain knowledge in different application areas, and introduces an expressive fuzzy description logic that extends classical description logics to many-valued logics. We represent, and reason with, uncertain knowledge in the description logic \(\mathcal{ALCHIN}\) extended to an interval-based, n...

In intensional languages meanings or values of intensional constructs such as variables vary in or depend on contexts of an underlying context space. The meaning or value of an construct can be defined by meanings of other constructs in different contexts by applying context switching operations. This paper proposes a graph-based formal method to a...

Mobile application developers and content providers usually need to develop mobile applications with concerns for mobility for specific wireless networks and device platforms which are used by network carriers. In order to provide standard mobile applications with interoperability and mobility support, in this paper we propose a comprehensive mobil...

Enriching test oracles with a test expert's mental model of error prone aspects of software, and granting control to them to specify custom coverage criteria and arbitrary test cases, can potentially improve the quality of automatically generated test suites. This paper reports our investigation on the application of knowledge engineering technique...

Semantic grids refer to those grids that their resources and services have been described by the means of semantic meta data and ontologies. In this paper we propose a resource discovery framework for semantic grids using the notion of modular ontologies. We exploit interface-based modular ontology formalism whose through ontologies can be describe...

In this paper, we present a framework for developing ontologies in a modular manner, which is based on the notions of interfaces and knowledge encapsulation. Within the context of this framework, an ontology can be defined and developed as a set of ontology modules that can access the knowledge bases of the others through their well-defined interfa...

A geographical information system (GIS) is a system that captures, analyzes, and manages any spatially referenced data. One common problem in the GIS community is how to generate and publish customized Web maps. The existing solutions either deal with spatial data directly which does not allow for applying the customized features, or require and re...

Modularization entails more ecient reasoning and better performance in the ontology manipulation process. Therefore, the devel- opment of modular ontologies has recently received much attention. One of the most important issues in modular ontologies is dealing with in- consistencies. An inconsistent module may aect the other modules and cause a mod...

In this paper we propose a high-level scheme that assists ontology engineers develop appropriate ontological frameworks. By ontological frameworks we mean those structures that specify particular phases and also provide implemented components for developing ontologies. Based on the i* conceptual modeling framework, our proposed scheme guides ontolo...

Provides a listing of current committee members and society officers.

This research aims at facilitating the development of context-aware application software for mobile devices by providing a programming model, an implementation framework and a development environment. The programming model provides a multi-layered software architecture for context-aware application programming. The model supports developers to defi...

In this paper, we attempt to study and investigate on- tology development and maintenance frameworks from a domain-centric point of view. By frameworks we mean the structures which have been designed to allow ontology en- gineers and domain experts to develop and maintain do- main ontologies. Such frameworks usually specify partic- ular phases for...

This paper describes an XML based agents technology for building web services based collaborative applications. The technology consists of XML Agents (XAs), XML Agent Hosts, and XML based Agent Communication Language (XACL). The XML based XAs and XACL messages are neutral to particular agent systems and programming languages. The XML Agent Hosts ar...

This thesis presents a Web services implementation of the infrastructure for e-Marketplaces based on e-Marketplace business patterns. Business patterns implemented by the infrastructure include User-to-Business, User-to-Online Buying, User-to-User, and Business-to-Business integration. The implementation of the User-to-Business pattern provides for...

In service-oriented distributed systems, software services are located in different computers; such services collaborate with each other to carry out computation tasks. This paper presents design and implementation of lightweight software brokers for quality of services in service-oriented distributed systems. Such brokers help clients in a distrib...

In software reuse, which is an important approach to improving the practice of software engineering, many factors may hinder reusing software artifacts. Among those factors are the availability of software artifacts at a different level of abstraction and a method to classify and retrieve them. This paper proposes an approach based on faceted class...

This paper presents the design and implementation of a high-level parallel programming system to support parallel execution of Fortran subprograms. The objective of the system is to unburden users from the responsibility of programming details including discovering and managing parallelism such as partitioning, mapping, scheduling, and load balanci...

This paper introduces an extension of logic programming based on multi-dimensional logics. In a multi-dimensional logic the values of elements vary depending on more than one dimension, such as time and space. The resulting logic programming language is suitable for modelling objects which involve implicit and/or explicit temporal and spatial depen...

This paper introduces an extension of logic programming based on multi-dimensional logics, called MLP. In a multi-dimensional logic the values of elements vary depending on more than one dimension, such as time and space. The resulting logic programming language is suitable for modelling objects which involve implicit and/or explicit temporal and s...

This paper presents specifications of systolic algorithms in a parallel functional language SysLucid. The language extends conventional functional languages by allowing meanings of program elements, such as variables or expressions, to vary in a context space consisting of temporal and spatial dimensions. In specifying systolic algorithms, the spat...

This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time temporal logic with unbounded past and future. Chronolog(Z) is suitable for applications involving the notion of dynamic change such as modeling nonterminating computations, the simulation of sequential circuits, and temporal databases. The execution of...

Unlike conventional parallel languages, intentional languages let developers think of parallelism first and then use explicit constructs to express sequentialism, instead of the other way around

This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time temporal logic with unbounded past and future. Chronolog(Z) is suitable for applications involving the notion of dynamic change such as modeling non-terminating computations, the simulation of sequential circuits, and temporal databases. The execution o...

Indexical programming languages enrich conventional programming languages by allowing the meanings of program constructs to depend on an implicit context. In an indexical program, values at different contexts can potentially be evaluated an parallel, resulting in context parallelism. This paper formally defines context parallelism in the indexical...

Some parallel programming techniques in the intensional functional language uLucid are presented. Programs in uLucid have a kind of implicit parallelism, context parallelism, when the processes that evaluate independent expressions at different contexts are executed in parallel. Communications among the processes that evaluate expressions with depe...

This paper presents an implementation technique for a three-dimensional spreadsheet based on a dataflow computation model called eduction. In the evaluation of a spreadsheet, initiated by the user's request, demands for values of various cells of the spreadsheet are sent out. The demands cause the operations computing the requested values to be per...

A three-dimensional spreadsheet design based on intensional logic is proposed. Intensional logic is concerned with assertions and other expressions whose meaning depends on an implicit context. The intensional spreadsheet is a declarative spreadsheet with a simple formal semantics called intensional semantics. It is expected to be suitable for a wi...

Plane Lucid is an extension of the language Lucid, a language based on intentional logic. The language allows values of expressions in a program to vary in space as well as in time; it provides spatial and temporal operators to combine values from different contexts (or different points in space and time). As an application of Plane Lucid, an inten...

This paper presents an object-oriented implementation of Lucid. We implement each variable in a Lucid program as a class. An object of the class is the variable in a context. An object evaluates itself when it receives a demand for its value and stores the value. Evaluation of a program involves object self-evaluations and message passing of demand...

The increasing desire for applying semantic web techniques for describing large and complex domains demanded scalable methods for developing ontologies. Modularity is an emerging approach for developing ontologies that leads to more scalable development process and better reasoning performance. In this chapter, we describe the interface-based modul...

One of the most important issues in the development of on- tologies is dealing with revisions and updates, which becomes even more prominent in modular representations of ontologies, in light of the fact that an update in one ontology module may lead to unintended conse- quences in other ontology modules due to their coupling. In this paper, we pro...

In the recent years, the software product lines paradigm has gained interest in both industry and academia. As in traditional software development, the concept of quality is crucial for the success of software product line practices and both functional and nonfunctional characteristics must be involved in the development process in order to achieve...

While applications in different areas have shown the necessity of dealing with uncertain knowledge, Semantic Web techniques based on standard Description Logics do not have such a capability. Motivated by this discrepancy, we introduce an expressive fuzzy description logic, fZSI , which extends the classic Description Logic SI to deal with uncertai...