Areas of computer applications are far wider than what people normally imagine. Besides the visib... more Areas of computer applications are far wider than what people normally imagine. Besides the visible applications like word processing and the Internet access using your desktop computer, computer applications cover a vast spectrum of areas, from nuclear reactor and aircraft control systems, to vehicle antilock brake systems (ABS) and electronic toys like play stations. Some of these applications are safety-critical, that is, catastrophic consequences may occur if a computer in the control system becomes faulty. Design errors and operational faults are in general not avoidable. All we can do are to make the probability of system failures as low as possible, or make the system as dependable as possible.
The aim of our research is to develop a distributed system that support a variety of tasks. Curre... more The aim of our research is to develop a distributed system that support a variety of tasks. Currently, we are implementing Internet applications on the system, including firewall, web and mail applications. These applications have different levels of dependability requirements. Depending on their criticality, a single task may execute on one, two or more computer nodes. Fault tolerant protocols are used to detect the disagreement among replicas. A reconfiguration protocol is used to identify the faulty nodes according to the fault reports from the fault tolerant protocols. It then isolates the faulty nodes from the system and reallocates their tasks to other working nodes. As a part of the project, this work focuses on the dependability analysis. The dependability attributes under modelling are the reliability of the system and the risk that an unacceptable packet is accepted in the firewall application.
ABSTRACT With the rapid growth of cloud services, huge energy consumption of the underlying large... more ABSTRACT With the rapid growth of cloud services, huge energy consumption of the underlying large-scale datacenters becomes a major concern of both the resource providers and the society. Datacenter owners are beginning to use renewable energy as extra supply for the devices. In this paper, we design a green-aware power management strategy for such datacenters powered by sustainable energy sources, considering the power consumption of both IT functional devices and cooling devices. Specifically, we make use of energy-aware methods to formulate an overall optimization problem, and try to solve it by combining heuristic and statistical searching approaches. The ultimate objective is to utilize green energy sufficiently while keeping the demand of applications deployed inside the datacenter at an acceptable level. Performance evaluation and simulation experiments are designed upon a simulated testbed, with realistic workload traces and solar energy generation considered, in order to validate the feasibility of our approach. Results show that it can significantly improve the green energy utilization, and achieve the highest overall revenues for the resource provider.
2006 Second IEEE International Symposium on Service-Oriented System Engineering (SOSE'06), 2006
... This is a difficult problem for component-based systems in general, and SOA systems in partic... more ... This is a difficult problem for component-based systems in general, and SOA systems in particular. The issue is that SOA applications may be dynamically composed, and thus many of testing and evaluation may need to be done at runtime. ...
2015 IEEE Twelfth International Symposium on Autonomous Decentralized Systems, 2015
This paper reports the newly designed first computer science and first programming course CSE101 ... more This paper reports the newly designed first computer science and first programming course CSE101 developed and taught at Arizona State University, and disseminated to many other universities, to address the enrollment crisis as reported by ACM CS Curriculum Committee Review Task Force in 2008. The course teaches the basic computer science and engineering concepts and gives the students the first programming experience through robotics programming. The initial curriculum and the ongoing improvement of the course are presented. The course started with its experiment environment using Microsoft Robotics Developer Studio, Visual Programming Language, and Lego Mind storms robots. The environment is extended to a Web-based programming environment and Intel architecture-based robots.
Proceedings 2000 International Workshop on Autonomous Decentralized System (Cat. No.00EX449), 2000
An ongoing project of the Programme for Highly Dependable Systems (PHDS) at the University of the... more An ongoing project of the Programme for Highly Dependable Systems (PHDS) at the University of the Witwatersrand is the development of a dependable decentralised system using readily available hardware and software components. An experimental system has been developed to support multiple-task applications with different levels of criticality. Fault-tolerant protocols are used to detect faults, to mask incorrect results from faulty nodes. A task in a faulty node can he recovered through a system reconfiguration or task reallocation. A faulty node can he repaired and reintegrated into the system. This paper focuses on modelling the system under the occurrence of faults, reconfiguration and repair. The method developed can be used to evaluate individual task's reliability, risk and availability.
Service-Oriented Architecture (SOA) is characterized by dynamic service discovery and composition... more Service-Oriented Architecture (SOA) is characterized by dynamic service discovery and composition. For user-centric SOA, not only services, workflows and application templates can be published and discovered for composition. Furthermore, a user can publish an application template and let providers supply the needed services. A key issue in user-centric service composition is to intelligently and effectively discover the subset of correlated services that best match the users’ requirements. This paper proposes a two-steps composition process. In the first step, users choose templates from ontology with its dependency. The dependency information identifies a set of candidate services and workflows that may be applicable for composition. In the send step, after the templates are selected, users can finalize the selection of services and workflows from a set of candidate services or workflows based on their preference. This 2-step process is supported by dependency identification algori...
International Journal of Critical Computer-Based Systems, 2011
This introductory note outlines autonomous decentralised systems (ADS) technologies as applied to... more This introductory note outlines autonomous decentralised systems (ADS) technologies as applied to service-oriented computing (SOC) and cloud computing environments, and also introduces the papers in the special issue.
2008 The 28th International Conference on Distributed Computing Systems Workshops, 2008
ABSTRACT Service-oriented computing (SOC) research and applications have been largely limited to ... more ABSTRACT Service-oriented computing (SOC) research and applications have been largely limited to software development in electronic and Web based applications. Service-oriented robotics software development extends SOC from its current fields to a new domain, which was considered not feasible because of the efficiency issues in terms of computing and communication. This paper presents the concepts, principles, and methods in SOC and SOC-based robotics software development and applies them in the design of distributed robotics applications. Two case studies, Intel security robot design and a maze-traversing robot application in Microsoft Robotics Studio, are used to illustrate the concepts and methods.
... enumerated class mutation. Because of the dynamic features, simulation is a necessity in WS t... more ... enumerated class mutation. Because of the dynamic features, simulation is a necessity in WS testing. Two categories of simulations are defined for SOAapplications [4]. Simulation for SOA and simulation in SOA. The former ...
One problem of the input domain-based software reliability models is the large number of test cas... more One problem of the input domain-based software reliability models is the large number of test cases required to obtain a high confidence in reliability estimation, because testing has to be restarted from beginning after any fault correction is performed. This paper intends to overcome this problem by considering relations between the programs before and after fault corrections and therefore making use of the testing data collected from the previous testing stages. For this purpose we propose an input domain-based reliability growth model. Both partition and random testing can be used to generate input cases for test runs. It is generally considered in the model that input generation, fault detection and fault correction are all imperfect. It will be shown that some existing reliability models can be viewed as the special cases of our model.
Areas of computer applications are far wider than what people normally imagine. Besides the visib... more Areas of computer applications are far wider than what people normally imagine. Besides the visible applications like word processing and the Internet access using your desktop computer, computer applications cover a vast spectrum of areas, from nuclear reactor and aircraft control systems, to vehicle antilock brake systems (ABS) and electronic toys like play stations. Some of these applications are safety-critical, that is, catastrophic consequences may occur if a computer in the control system becomes faulty. Design errors and operational faults are in general not avoidable. All we can do are to make the probability of system failures as low as possible, or make the system as dependable as possible.
The aim of our research is to develop a distributed system that support a variety of tasks. Curre... more The aim of our research is to develop a distributed system that support a variety of tasks. Currently, we are implementing Internet applications on the system, including firewall, web and mail applications. These applications have different levels of dependability requirements. Depending on their criticality, a single task may execute on one, two or more computer nodes. Fault tolerant protocols are used to detect the disagreement among replicas. A reconfiguration protocol is used to identify the faulty nodes according to the fault reports from the fault tolerant protocols. It then isolates the faulty nodes from the system and reallocates their tasks to other working nodes. As a part of the project, this work focuses on the dependability analysis. The dependability attributes under modelling are the reliability of the system and the risk that an unacceptable packet is accepted in the firewall application.
ABSTRACT With the rapid growth of cloud services, huge energy consumption of the underlying large... more ABSTRACT With the rapid growth of cloud services, huge energy consumption of the underlying large-scale datacenters becomes a major concern of both the resource providers and the society. Datacenter owners are beginning to use renewable energy as extra supply for the devices. In this paper, we design a green-aware power management strategy for such datacenters powered by sustainable energy sources, considering the power consumption of both IT functional devices and cooling devices. Specifically, we make use of energy-aware methods to formulate an overall optimization problem, and try to solve it by combining heuristic and statistical searching approaches. The ultimate objective is to utilize green energy sufficiently while keeping the demand of applications deployed inside the datacenter at an acceptable level. Performance evaluation and simulation experiments are designed upon a simulated testbed, with realistic workload traces and solar energy generation considered, in order to validate the feasibility of our approach. Results show that it can significantly improve the green energy utilization, and achieve the highest overall revenues for the resource provider.
2006 Second IEEE International Symposium on Service-Oriented System Engineering (SOSE'06), 2006
... This is a difficult problem for component-based systems in general, and SOA systems in partic... more ... This is a difficult problem for component-based systems in general, and SOA systems in particular. The issue is that SOA applications may be dynamically composed, and thus many of testing and evaluation may need to be done at runtime. ...
2015 IEEE Twelfth International Symposium on Autonomous Decentralized Systems, 2015
This paper reports the newly designed first computer science and first programming course CSE101 ... more This paper reports the newly designed first computer science and first programming course CSE101 developed and taught at Arizona State University, and disseminated to many other universities, to address the enrollment crisis as reported by ACM CS Curriculum Committee Review Task Force in 2008. The course teaches the basic computer science and engineering concepts and gives the students the first programming experience through robotics programming. The initial curriculum and the ongoing improvement of the course are presented. The course started with its experiment environment using Microsoft Robotics Developer Studio, Visual Programming Language, and Lego Mind storms robots. The environment is extended to a Web-based programming environment and Intel architecture-based robots.
Proceedings 2000 International Workshop on Autonomous Decentralized System (Cat. No.00EX449), 2000
An ongoing project of the Programme for Highly Dependable Systems (PHDS) at the University of the... more An ongoing project of the Programme for Highly Dependable Systems (PHDS) at the University of the Witwatersrand is the development of a dependable decentralised system using readily available hardware and software components. An experimental system has been developed to support multiple-task applications with different levels of criticality. Fault-tolerant protocols are used to detect faults, to mask incorrect results from faulty nodes. A task in a faulty node can he recovered through a system reconfiguration or task reallocation. A faulty node can he repaired and reintegrated into the system. This paper focuses on modelling the system under the occurrence of faults, reconfiguration and repair. The method developed can be used to evaluate individual task's reliability, risk and availability.
Service-Oriented Architecture (SOA) is characterized by dynamic service discovery and composition... more Service-Oriented Architecture (SOA) is characterized by dynamic service discovery and composition. For user-centric SOA, not only services, workflows and application templates can be published and discovered for composition. Furthermore, a user can publish an application template and let providers supply the needed services. A key issue in user-centric service composition is to intelligently and effectively discover the subset of correlated services that best match the users’ requirements. This paper proposes a two-steps composition process. In the first step, users choose templates from ontology with its dependency. The dependency information identifies a set of candidate services and workflows that may be applicable for composition. In the send step, after the templates are selected, users can finalize the selection of services and workflows from a set of candidate services or workflows based on their preference. This 2-step process is supported by dependency identification algori...
International Journal of Critical Computer-Based Systems, 2011
This introductory note outlines autonomous decentralised systems (ADS) technologies as applied to... more This introductory note outlines autonomous decentralised systems (ADS) technologies as applied to service-oriented computing (SOC) and cloud computing environments, and also introduces the papers in the special issue.
2008 The 28th International Conference on Distributed Computing Systems Workshops, 2008
ABSTRACT Service-oriented computing (SOC) research and applications have been largely limited to ... more ABSTRACT Service-oriented computing (SOC) research and applications have been largely limited to software development in electronic and Web based applications. Service-oriented robotics software development extends SOC from its current fields to a new domain, which was considered not feasible because of the efficiency issues in terms of computing and communication. This paper presents the concepts, principles, and methods in SOC and SOC-based robotics software development and applies them in the design of distributed robotics applications. Two case studies, Intel security robot design and a maze-traversing robot application in Microsoft Robotics Studio, are used to illustrate the concepts and methods.
... enumerated class mutation. Because of the dynamic features, simulation is a necessity in WS t... more ... enumerated class mutation. Because of the dynamic features, simulation is a necessity in WS testing. Two categories of simulations are defined for SOAapplications [4]. Simulation for SOA and simulation in SOA. The former ...
One problem of the input domain-based software reliability models is the large number of test cas... more One problem of the input domain-based software reliability models is the large number of test cases required to obtain a high confidence in reliability estimation, because testing has to be restarted from beginning after any fault correction is performed. This paper intends to overcome this problem by considering relations between the programs before and after fault corrections and therefore making use of the testing data collected from the previous testing stages. For this purpose we propose an input domain-based reliability growth model. Both partition and random testing can be used to generate input cases for test runs. It is generally considered in the model that input generation, fault detection and fault correction are all imperfect. It will be shown that some existing reliability models can be viewed as the special cases of our model.
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Papers by Yinong Chen