Skip to main content

Dazhi Huang

Rhode Island School of Design, Film, Department Member

Followers

31

Following

36

Public Views

Newcastle University

Samson Abramsky

University of Oxford

Universidade Nova de Lisboa

Università Degli Studi Dell'Aquila

Politecnico di Milano

Nigamanth Sridhar

Cleveland State University

Purdue University

Carlos E Cuesta

Universidad Rey Juan Carlos

Pablo de la Fuente

Interests

Uploads

Papers by Dazhi Huang

Automated Agent Synthesis for Situation Awareness in Service-Based Systems

Service-based systems have many applications, such as collaborative research and development, e-b... more Service-based systems have many applications, such as collaborative research and development, e-business, health care, military applications, and homeland security. In dynamic service-oriented computing environment, situation awareness (SAW) is needed for system status monitoring, adaptive service coordination and flexible security policy enforcement. Furthermore, various application software systems in such environments often need to reuse situational information for providing better quality of service. Hence, to greatly reduce the effort of situation-aware application software development in service-based systems as well as supporting runtime system adaptation, it is necessary to automate the development of reusable and autonomous software components, referred to as SAW agents, for context acquisition, situation analysis and reactive behaviors of the systems. In this paper, an automated agent synthesis approach for SAW in service-based systems is presented. This approach is based on AS 3 calculus and logic, and our declarative model for SAW.

Dual-channel-output all-optical logic AND gate at 20 Gbit/s based on cascaded second-order nonlinearity in PPLN waveguide

Electronics Letters, 2007

Automated Agent Synthesis for Situation-Aware Service Coordination in Service-based Systems

Service-based systems have many applications, including collaborative research and development, e... more Service-based systems have many applications, including collaborative research and development, e-business, health care, environmental control, military applications, and homeland security. Situation-aware service coordination is required for these systems to coordinate distributed activities under changing environment and workload. In this paper, an automated agent synthesis approach for situation-aware service coordination in service-based systems is presented. This approach is based on AS 3 logic and calculus, and our declarative model for SAW, which are also presented in this paper. This approach consists of three major steps: (1) analyzing situation-awareness (SAW) requirements using our declarative model for SAW and mapping the model representations to logical specifications in AS 3 logic, (2) automated synthesis of AS 3 calculus terms that define SAW agents for situation-aware service coordination, and (3) compilation of AS 3 calculus terms to execution components on an agent platform. An example is presented to illustrate our approach.

Middleware Support for Embedded Software with Multiple QoS Properties for Ubiquitous Computing Environments

Ubiquitous application software usually has multiple QoS requirements, such as situationawareness... more Ubiquitous application software usually has multiple QoS requirements, such as situationawareness, real-time, and security, which make the application software development complicated. In this paper, an approach to supporting multiple QoS properties in application software using middleware is presented. Our Reconfigurable Context-Sensitive Middleware (RCSM), which provides situation-awareness support to the application software, is expanded to support more QoS by using Aspect-Oriented Software Development techniques. In the expanded RCSM, each QoS is processed through a set of aspect components. The application developers specify the QoS requirements in a specification file, which is in turn compiled to configure the corresponding aspect components. Being associated with certain application objects, the QoS aspect components enforce the QoS requirements according to the specification during run-time. In this paper, security, in addition to situation-awareness, is used as an example to illustrate our approach.

Development and Runtime Support for Situation-Aware Application Software in Ubiquitous Computing Environments

Due to the dynamic and ephemeral nature of ubiquitous computing (ubicomp) environments, it is nec... more Due to the dynamic and ephemeral nature of ubiquitous computing (ubicomp) environments, it is necessary that application software in ubicomp environments is situationaware (SA) and should be adaptable to both users' situation changes and the requirement changes. Reconfigurable Context-Sensitive Middleware (RCSM) has been developed to provide development and runtime support for SA software in ubicomp environments, but do not provide runtime support for on-demand context acquisition, action scheduling and dynamic reconfiguration of SA software, and development support that maximize the reusability. In this paper, the development and runtime support provided by RCSM have been substantially expanded to greatly simplify the development of situation-aware application software, and to achieve reusability and runtime reconfigurability simultaneously.

Situation-Aware Personalized Information Retrieval for Mobile Internet

Recent rapid advances in Internet-based information systems and handheld devices make it possible... more Recent rapid advances in Internet-based information systems and handheld devices make it possible for users to retrieve information anytime and anywhere. Existing information retrieval (IR) techniques usually require the users to spend much effort to continuously refine their queries to obtain the results they want. Since each refinement is an interaction between a user and information systems, the larger the number of interactions, the more communication overhead and energy consumption are introduced. Due to the severe resource constraints of handheld devices, it is necessary to have an IR technique that can efficiently retrieve information for the user with only one or two interactions. In this paper, an efficient IR technique for mobile Internet by combining situation-based adaptation and profile-based personalization is presented.

40 Gbit/s reconfigurable photonic logic gates based on various nonlinearities in single SOA

Electronics Letters, 2007

ABSTRACT

Toward Development of Adaptive Service-Based Software Systems

IEEE Transactions on Services Computing, 2009

The rapid adoption of service-oriented architecture (SOA) in many large-scale distributed applica... more The rapid adoption of service-oriented architecture (SOA) in many large-scale distributed applications requires the development of adaptive service-based software systems (ASBS) with the capability of monitoring the changing system status, analyzing, and controlling tradeoffs among various quality-of-service (QoS) aspects, and adapting service configurations to satisfy multiple QoS requirements simultaneously. In this paper, our results toward the development of adaptive service-based software systems are presented. The formulation of Activity-State-QoS (ASQ) models and how to use the data from controlled experiments to establish ASQ models for capturing the cause-effect dynamics among service activities, system resource states, and QoS in servicebased systems are presented. Then, QoS monitoring modules based on ASQ models and SOA-compliant simulation models are developed to support the validation of the ASBS design. The main idea for developing QoS adaptation modules based on ASQ models is discussed. An experiment based on a voice communication service is used to illustrate our results.

Specification, decomposition and agent synthesis for situation-aware service-based systems

Journal of Systems and Software, 2008

Service-based systems are distributed computing systems with the major advantage of enabling rapi... more Service-based systems are distributed computing systems with the major advantage of enabling rapid composition of distributed applications, such as collaborative research and development, e-business, health care, military applications and homeland security, regardless of the programming languages and platforms used in developing and running various components of the applications. In dynamic service-oriented computing environment, situation awareness (SAW) is needed for system

An Intelligent Control Architecture for Adaptive Service-Based Software Systems with Workflow Patterns

Service-oriented architecture (SOA) for distributed computing has become increasingly popular due... more Service-oriented architecture (SOA) for distributed computing has become increasingly popular due to the great advantage that distributed applications can be rapidly synthesized with the needed services provided by various service providers through broadband networks. Systems based on SOA are called Service-based Systems (SBS). An important and difficult issue is how to develop SBS adaptable to constantly changing user requirements, environments and resource constraints. In this paper, an intelligent control architecture is presented to address this issue. This architecture has three layers based on the intelligent control theory for developing and deploying SBS. An example to illustrate the intelligent control architecture for adaptive SBS is given and preliminary experimental data is presented to demonstrate the feasibility of our approach.

Support for situation awareness in trustworthy ubiquitous computing application software

Software - Practice and Experience, 2006

important that the application software in ubicomp environments is trustworthy. In order to have ... more important that the application software in ubicomp environments is trustworthy. In order to have trustworthy application software in ubicomp environments, situation-awareness (SAW) in the application software is needed for enforcing flexible security policies and detecting violations of security policies. In this paper, an approach is presented to providing development and runtime support for incorporating SAW in trustworthy ubicomp application software. The development support is to provide SAW requirement specification and automated code generation for achieving SAW in trustworthy ubicomp application software, and the runtime support is for context acquisition, situation analysis, and situation-aware communication. To realize our approach, the improved Reconfigurable Context-Sensitive Middleware (RCSM) is developed for providing the above development and runtime support.

An Approach to Adaptive Distributed Execution Monitoring for Workflows in Service-based Systems

Systems based on Service-Oriented Architecture are called service-based systems (SBS), and compri... more Systems based on Service-Oriented Architecture are called service-based systems (SBS), and comprise of computing services offered by various organizations. Users of SBS often require these services to be composed into complex workflows to perform their high-level tasks. The users usually have certain expectations on the overall QoS of their workflows. Due to the highly dynamic environments of SBS, in which temporary unavailability or qualitydegradation of services may occur frequently and unexpectedly, monitoring the execution of workflows in SBS is necessary, and should be done in distributed and proactive manner. In this paper, a virtual machine-based architecture for the execution, monitoring and control of workflows in SBS is presented. Based on this architecture, an approach to automated generation of workflow monitors for adaptive distributed execution monitoring of workflows in SBS is discussed

An Adaptive, Lightweight and Energy-Efficient Context Discovery Protocol for Ubiquitous Computing Environments

In ubiquitous computing (ubicomp) environments, it is often necessary for the applications to hav... more In ubiquitous computing (ubicomp) environments, it is often necessary for the applications to have situationawareness capability. Current research on situation-aware applications is mainly based on situations with a predefined set of contexts. To achieve more flexible situationawareness, situation-aware applications should have the ability to discover and collect contexts in a timely and organized fashion. Due to the dynamic and ephemeral nature of ubicomp environments, a context discovery protocol (CDP) that defines the entire process of discovering, acquiring, aggregating and storing contexts, is needed. Because of the serious resource constraints on ubicomp devices, the CDP must be adaptive, lightweight and energy-efficient. In this paper, a CDP with such characteristics for ubicomp environments is presented. The experimental results to show that our CDP is more energyefficient and has a small increase in latency, compared to a simple context discovery protocol, are also presented.

A Framework for Extensible Component Customization for Component-based Software Development

Component-based software development (CBSD) increases productivity of software developers and imp... more Component-based software development (CBSD) increases productivity of software developers and improves overall software quality due to high degree of reusability. To achieve the full potential of CBSD, it is necessary for software developers to be able to customize components because it is rare to find the components completely matching their functional and non-functional requirements in the new applications. Existing customization

Developing Service-Based Software Systems with QoS Monitoring and Adaptation

The rapid adoption of SOA in many large-scale distributed applications requires the development o... more The rapid adoption of SOA in many large-scale distributed applications requires the development of adaptive service-based software systems (ASBS), which have the capability of monitoring the changing system status, analyzing and controlling tradeoffs among multiple QoS features, and adapting its service configuration to satisfy multiple QoS requirements simultaneously. In this paper, a performance-modeloriented approach to developing ASBS is presented. This approach consists of the establishment of performance models for SBS through controlled experiments, the development of QoS monitoring and adaptation (M/A) modules based on the performance models, and the validation of ASBS design through simulations. In our approach, four QoS features: timeliness, throughput, accuracy and security, which are important for many critical applications, are considered.

Automated Situation-Aware Service Composition in Service-Oriented Computing

International Journal of Web Services Research, 2007

Service-based systems have many applications, such as e-business, health care, and homeland secur... more Service-based systems have many applications, such as e-business, health care, and homeland security. In these systems, it is necessary to provide users the capability of composing services into workflows providing higher-level functionality. In dynamic service-oriented computing environments, it is desirable that service composition is automated and situation-aware to generate robust and adaptive workflows. In this paper, an automated situation-aware service composition approach is presented. This approach is based on the a-logic, a-calculus, and a declarative model for situation awareness (SAW). This approach consists of four major components: (1) analyzing SAW requirements using our SAW model, (2) translating our SAW model representation to a-logic specifications and specifying a control flow graph in a-logic as the service composition goal, (3) automated synthesis of a-calculus terms defining situation-aware workflow agents based on a-logic specifications for SAW requirements and the control flow graph, and (4) compilation of a-calculus terms to executable components.

Adaptable Situation-Aware Secure Service-Based (AS3) Systems

Service-oriented systems are distributed systems which have the major advantage of enabling rapid... more Service-oriented systems are distributed systems which have the major advantage of enabling rapid composition of distributed applications, regardless of the programming languages and platforms used in developing and running different components of the applications. In these systems, various capabilities are provided by different organizations as services interconnected by various types of networks. The services can be integrated following a specific workflow to achieve a mission goal for users. For large-scale service-based systems involving multiple organizations, high confidence and adaptability are of prime concern in order to ensure that users can use these systems anywhere, anytime with various devices, knowing that their confidentiality and privacy are well protected and the systems will adapt to satisfy their needs in various situations. Hence, these systems must be adaptable, situation-aware and secure. In this paper, an approach to rapid development of adaptable situation-aware secure service-based (AS 3 ) systems is presented. Our approach enables users to rapidly generate, discover, compose services into processes to achieve their goals based on the situation and adapt these processes when situation changes.

Situation-Aware Contract Specification Language for Middleware for Ubiquitous Computing

Ubicomp applications are characterized as situationaware, frequently-and-ephemerally-communicated... more Ubicomp applications are characterized as situationaware, frequently-and-ephemerally-communicated and QoS-properties-associated. Using middleware to provide multiple QoS support for these ubicomp applications will enhance the development of the ubicomp applications. To satisfy the different QoS requirements of various applications in ubicomp environments, which are heterogeneous and resource-variant, it is important for the underlining middleware to adapt to different QoS requirements and environments. Situation-Aware Contract Specification Language (SA-CSL) specifies the QoS requirements of the applications. The specification includes requirements in situation-awareness, real-time constraints and security properties. This specification is used to customize the middleware architecture to better satisfy these requirements. SA-CSL is based on the Separation of Concern (SoC) discipline used in the Aspect-Oriented Software Development (AOSD). It specifies the crosscutting aspects of situation-awareness, real-time constraints and security property separately. Because of the object-oriented design, SA-CSL is open for incorporating new QoS properties specification.

A Middleware Situation-Aware Contact Specification Language for Ubiquitous Computing

Design of Service-Based Systems with Adaptive Tradeoff Between Security and Service Delay

Service-based Systems (SBS) have the advantage of composing distributed systems from various serv... more Service-based Systems (SBS) have the advantage of composing distributed systems from various services provided by multiple providers transparently. In addition to functional correctness, multiple non-functional QoS requirements should also be satisfied in such systems. Among these QoS requirements, security protection and real-time performance are the two major concerns. However, neither application users, nor service providers, have adequate control over such QoS of SBS. In this paper, an approach to the design of SBS with the capability of tradeoff between security and service delay of composite services running across various service hosts is presented in order to satisfy both security and real-time performance requirements simultaneously.

Automated Agent Synthesis for Situation Awareness in Service-Based Systems

Service-based systems have many applications, such as collaborative research and development, e-b... more Service-based systems have many applications, such as collaborative research and development, e-business, health care, military applications, and homeland security. In dynamic service-oriented computing environment, situation awareness (SAW) is needed for system status monitoring, adaptive service coordination and flexible security policy enforcement. Furthermore, various application software systems in such environments often need to reuse situational information for providing better quality of service. Hence, to greatly reduce the effort of situation-aware application software development in service-based systems as well as supporting runtime system adaptation, it is necessary to automate the development of reusable and autonomous software components, referred to as SAW agents, for context acquisition, situation analysis and reactive behaviors of the systems. In this paper, an automated agent synthesis approach for SAW in service-based systems is presented. This approach is based on AS 3 calculus and logic, and our declarative model for SAW.

Dual-channel-output all-optical logic AND gate at 20 Gbit/s based on cascaded second-order nonlinearity in PPLN waveguide

Electronics Letters, 2007

Automated Agent Synthesis for Situation-Aware Service Coordination in Service-based Systems

Service-based systems have many applications, including collaborative research and development, e... more Service-based systems have many applications, including collaborative research and development, e-business, health care, environmental control, military applications, and homeland security. Situation-aware service coordination is required for these systems to coordinate distributed activities under changing environment and workload. In this paper, an automated agent synthesis approach for situation-aware service coordination in service-based systems is presented. This approach is based on AS 3 logic and calculus, and our declarative model for SAW, which are also presented in this paper. This approach consists of three major steps: (1) analyzing situation-awareness (SAW) requirements using our declarative model for SAW and mapping the model representations to logical specifications in AS 3 logic, (2) automated synthesis of AS 3 calculus terms that define SAW agents for situation-aware service coordination, and (3) compilation of AS 3 calculus terms to execution components on an agent platform. An example is presented to illustrate our approach.

Middleware Support for Embedded Software with Multiple QoS Properties for Ubiquitous Computing Environments

Ubiquitous application software usually has multiple QoS requirements, such as situationawareness... more Ubiquitous application software usually has multiple QoS requirements, such as situationawareness, real-time, and security, which make the application software development complicated. In this paper, an approach to supporting multiple QoS properties in application software using middleware is presented. Our Reconfigurable Context-Sensitive Middleware (RCSM), which provides situation-awareness support to the application software, is expanded to support more QoS by using Aspect-Oriented Software Development techniques. In the expanded RCSM, each QoS is processed through a set of aspect components. The application developers specify the QoS requirements in a specification file, which is in turn compiled to configure the corresponding aspect components. Being associated with certain application objects, the QoS aspect components enforce the QoS requirements according to the specification during run-time. In this paper, security, in addition to situation-awareness, is used as an example to illustrate our approach.

Development and Runtime Support for Situation-Aware Application Software in Ubiquitous Computing Environments

Due to the dynamic and ephemeral nature of ubiquitous computing (ubicomp) environments, it is nec... more Due to the dynamic and ephemeral nature of ubiquitous computing (ubicomp) environments, it is necessary that application software in ubicomp environments is situationaware (SA) and should be adaptable to both users' situation changes and the requirement changes. Reconfigurable Context-Sensitive Middleware (RCSM) has been developed to provide development and runtime support for SA software in ubicomp environments, but do not provide runtime support for on-demand context acquisition, action scheduling and dynamic reconfiguration of SA software, and development support that maximize the reusability. In this paper, the development and runtime support provided by RCSM have been substantially expanded to greatly simplify the development of situation-aware application software, and to achieve reusability and runtime reconfigurability simultaneously.

Situation-Aware Personalized Information Retrieval for Mobile Internet

Recent rapid advances in Internet-based information systems and handheld devices make it possible... more Recent rapid advances in Internet-based information systems and handheld devices make it possible for users to retrieve information anytime and anywhere. Existing information retrieval (IR) techniques usually require the users to spend much effort to continuously refine their queries to obtain the results they want. Since each refinement is an interaction between a user and information systems, the larger the number of interactions, the more communication overhead and energy consumption are introduced. Due to the severe resource constraints of handheld devices, it is necessary to have an IR technique that can efficiently retrieve information for the user with only one or two interactions. In this paper, an efficient IR technique for mobile Internet by combining situation-based adaptation and profile-based personalization is presented.

40 Gbit/s reconfigurable photonic logic gates based on various nonlinearities in single SOA

Electronics Letters, 2007

ABSTRACT

Toward Development of Adaptive Service-Based Software Systems

IEEE Transactions on Services Computing, 2009

The rapid adoption of service-oriented architecture (SOA) in many large-scale distributed applica... more The rapid adoption of service-oriented architecture (SOA) in many large-scale distributed applications requires the development of adaptive service-based software systems (ASBS) with the capability of monitoring the changing system status, analyzing, and controlling tradeoffs among various quality-of-service (QoS) aspects, and adapting service configurations to satisfy multiple QoS requirements simultaneously. In this paper, our results toward the development of adaptive service-based software systems are presented. The formulation of Activity-State-QoS (ASQ) models and how to use the data from controlled experiments to establish ASQ models for capturing the cause-effect dynamics among service activities, system resource states, and QoS in servicebased systems are presented. Then, QoS monitoring modules based on ASQ models and SOA-compliant simulation models are developed to support the validation of the ASBS design. The main idea for developing QoS adaptation modules based on ASQ models is discussed. An experiment based on a voice communication service is used to illustrate our results.

Specification, decomposition and agent synthesis for situation-aware service-based systems

Journal of Systems and Software, 2008

Service-based systems are distributed computing systems with the major advantage of enabling rapi... more Service-based systems are distributed computing systems with the major advantage of enabling rapid composition of distributed applications, such as collaborative research and development, e-business, health care, military applications and homeland security, regardless of the programming languages and platforms used in developing and running various components of the applications. In dynamic service-oriented computing environment, situation awareness (SAW) is needed for system

An Intelligent Control Architecture for Adaptive Service-Based Software Systems with Workflow Patterns

Service-oriented architecture (SOA) for distributed computing has become increasingly popular due... more Service-oriented architecture (SOA) for distributed computing has become increasingly popular due to the great advantage that distributed applications can be rapidly synthesized with the needed services provided by various service providers through broadband networks. Systems based on SOA are called Service-based Systems (SBS). An important and difficult issue is how to develop SBS adaptable to constantly changing user requirements, environments and resource constraints. In this paper, an intelligent control architecture is presented to address this issue. This architecture has three layers based on the intelligent control theory for developing and deploying SBS. An example to illustrate the intelligent control architecture for adaptive SBS is given and preliminary experimental data is presented to demonstrate the feasibility of our approach.

Support for situation awareness in trustworthy ubiquitous computing application software

Software - Practice and Experience, 2006

important that the application software in ubicomp environments is trustworthy. In order to have ... more important that the application software in ubicomp environments is trustworthy. In order to have trustworthy application software in ubicomp environments, situation-awareness (SAW) in the application software is needed for enforcing flexible security policies and detecting violations of security policies. In this paper, an approach is presented to providing development and runtime support for incorporating SAW in trustworthy ubicomp application software. The development support is to provide SAW requirement specification and automated code generation for achieving SAW in trustworthy ubicomp application software, and the runtime support is for context acquisition, situation analysis, and situation-aware communication. To realize our approach, the improved Reconfigurable Context-Sensitive Middleware (RCSM) is developed for providing the above development and runtime support.

An Approach to Adaptive Distributed Execution Monitoring for Workflows in Service-based Systems

Systems based on Service-Oriented Architecture are called service-based systems (SBS), and compri... more Systems based on Service-Oriented Architecture are called service-based systems (SBS), and comprise of computing services offered by various organizations. Users of SBS often require these services to be composed into complex workflows to perform their high-level tasks. The users usually have certain expectations on the overall QoS of their workflows. Due to the highly dynamic environments of SBS, in which temporary unavailability or qualitydegradation of services may occur frequently and unexpectedly, monitoring the execution of workflows in SBS is necessary, and should be done in distributed and proactive manner. In this paper, a virtual machine-based architecture for the execution, monitoring and control of workflows in SBS is presented. Based on this architecture, an approach to automated generation of workflow monitors for adaptive distributed execution monitoring of workflows in SBS is discussed

An Adaptive, Lightweight and Energy-Efficient Context Discovery Protocol for Ubiquitous Computing Environments

In ubiquitous computing (ubicomp) environments, it is often necessary for the applications to hav... more In ubiquitous computing (ubicomp) environments, it is often necessary for the applications to have situationawareness capability. Current research on situation-aware applications is mainly based on situations with a predefined set of contexts. To achieve more flexible situationawareness, situation-aware applications should have the ability to discover and collect contexts in a timely and organized fashion. Due to the dynamic and ephemeral nature of ubicomp environments, a context discovery protocol (CDP) that defines the entire process of discovering, acquiring, aggregating and storing contexts, is needed. Because of the serious resource constraints on ubicomp devices, the CDP must be adaptive, lightweight and energy-efficient. In this paper, a CDP with such characteristics for ubicomp environments is presented. The experimental results to show that our CDP is more energyefficient and has a small increase in latency, compared to a simple context discovery protocol, are also presented.

A Framework for Extensible Component Customization for Component-based Software Development

Component-based software development (CBSD) increases productivity of software developers and imp... more Component-based software development (CBSD) increases productivity of software developers and improves overall software quality due to high degree of reusability. To achieve the full potential of CBSD, it is necessary for software developers to be able to customize components because it is rare to find the components completely matching their functional and non-functional requirements in the new applications. Existing customization

Developing Service-Based Software Systems with QoS Monitoring and Adaptation

The rapid adoption of SOA in many large-scale distributed applications requires the development o... more The rapid adoption of SOA in many large-scale distributed applications requires the development of adaptive service-based software systems (ASBS), which have the capability of monitoring the changing system status, analyzing and controlling tradeoffs among multiple QoS features, and adapting its service configuration to satisfy multiple QoS requirements simultaneously. In this paper, a performance-modeloriented approach to developing ASBS is presented. This approach consists of the establishment of performance models for SBS through controlled experiments, the development of QoS monitoring and adaptation (M/A) modules based on the performance models, and the validation of ASBS design through simulations. In our approach, four QoS features: timeliness, throughput, accuracy and security, which are important for many critical applications, are considered.

Automated Situation-Aware Service Composition in Service-Oriented Computing

International Journal of Web Services Research, 2007

Service-based systems have many applications, such as e-business, health care, and homeland secur... more Service-based systems have many applications, such as e-business, health care, and homeland security. In these systems, it is necessary to provide users the capability of composing services into workflows providing higher-level functionality. In dynamic service-oriented computing environments, it is desirable that service composition is automated and situation-aware to generate robust and adaptive workflows. In this paper, an automated situation-aware service composition approach is presented. This approach is based on the a-logic, a-calculus, and a declarative model for situation awareness (SAW). This approach consists of four major components: (1) analyzing SAW requirements using our SAW model, (2) translating our SAW model representation to a-logic specifications and specifying a control flow graph in a-logic as the service composition goal, (3) automated synthesis of a-calculus terms defining situation-aware workflow agents based on a-logic specifications for SAW requirements and the control flow graph, and (4) compilation of a-calculus terms to executable components.

Adaptable Situation-Aware Secure Service-Based (AS3) Systems

Service-oriented systems are distributed systems which have the major advantage of enabling rapid... more Service-oriented systems are distributed systems which have the major advantage of enabling rapid composition of distributed applications, regardless of the programming languages and platforms used in developing and running different components of the applications. In these systems, various capabilities are provided by different organizations as services interconnected by various types of networks. The services can be integrated following a specific workflow to achieve a mission goal for users. For large-scale service-based systems involving multiple organizations, high confidence and adaptability are of prime concern in order to ensure that users can use these systems anywhere, anytime with various devices, knowing that their confidentiality and privacy are well protected and the systems will adapt to satisfy their needs in various situations. Hence, these systems must be adaptable, situation-aware and secure. In this paper, an approach to rapid development of adaptable situation-aware secure service-based (AS 3 ) systems is presented. Our approach enables users to rapidly generate, discover, compose services into processes to achieve their goals based on the situation and adapt these processes when situation changes.

Situation-Aware Contract Specification Language for Middleware for Ubiquitous Computing

Ubicomp applications are characterized as situationaware, frequently-and-ephemerally-communicated... more Ubicomp applications are characterized as situationaware, frequently-and-ephemerally-communicated and QoS-properties-associated. Using middleware to provide multiple QoS support for these ubicomp applications will enhance the development of the ubicomp applications. To satisfy the different QoS requirements of various applications in ubicomp environments, which are heterogeneous and resource-variant, it is important for the underlining middleware to adapt to different QoS requirements and environments. Situation-Aware Contract Specification Language (SA-CSL) specifies the QoS requirements of the applications. The specification includes requirements in situation-awareness, real-time constraints and security properties. This specification is used to customize the middleware architecture to better satisfy these requirements. SA-CSL is based on the Separation of Concern (SoC) discipline used in the Aspect-Oriented Software Development (AOSD). It specifies the crosscutting aspects of situation-awareness, real-time constraints and security property separately. Because of the object-oriented design, SA-CSL is open for incorporating new QoS properties specification.

A Middleware Situation-Aware Contact Specification Language for Ubiquitous Computing

Design of Service-Based Systems with Adaptive Tradeoff Between Security and Service Delay

Service-based Systems (SBS) have the advantage of composing distributed systems from various serv... more Service-based Systems (SBS) have the advantage of composing distributed systems from various services provided by multiple providers transparently. In addition to functional correctness, multiple non-functional QoS requirements should also be satisfied in such systems. Among these QoS requirements, security protection and real-time performance are the two major concerns. However, neither application users, nor service providers, have adequate control over such QoS of SBS. In this paper, an approach to the design of SBS with the capability of tradeoff between security and service delay of composite services running across various service hosts is presented in order to satisfy both security and real-time performance requirements simultaneously.