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Full-Text Articles in Computer Engineering

A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu Aug 2008

A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu

Zheng Sun

Conventional heterogeneous-traffic scheduling schemes utilize zero-delay constraint for real-time services, which aims to minimize the average packet delay among real-time users. However, in light or moderate load networks this strategy is unnecessary and leads to low data throughput for non-real-time users. In this paper, we propose a heuristic scheduling scheme to solve this problem. The scheme measures and assigns scheduling priorities to both real-time and non-real-time users, and schedules the radio resources for the two user classes simultaneously. Simulation results show that the proposed scheme efficiently handles the heterogeneous-traffic scheduling with diverse QoS requirements and alleviates the unfairness between real-time ...


Report Of The Commission To Assess The Threat To The United States From Emp Attack: Critical National Infrastructures, William R. Graham Jul 2008

Report Of The Commission To Assess The Threat To The United States From Emp Attack: Critical National Infrastructures, William R. Graham

George H Baker

The physical and social fabric of the United States is sustained by a system of systems; a complex and dynamic network of interlocking and interdependent infrastructures (“critical national infrastructures”) whose harmonious functioning enables the myriad actions, transactions, and information flow that undergird the orderly conduct of civil society in this country. The vulnerability of these frastructures to threats — deliberate, accidental, and acts of nature — is the focus of greatly heightened concern in the current era, a process accelerated by the events of 9/11 and recent hurricanes, including Katrina and Rita. This report presents the results of the Commission’s ...


Verifying Semantic Business Process Models In Inter-Operation, George Koliadis, Aditya Ghose Jun 2008

Verifying Semantic Business Process Models In Inter-Operation, George Koliadis, Aditya Ghose

Professor Aditya K. Ghose

Process inter-operation is characterized as cooperative interactions among loosely coupled autonomous constituents to adaptively fulfill system-wide purpose. Issues of inconsistency can be anticipated in inter-operating processes given their independent management and design. To reduce inconsistency (that may contribute to failures) effective methods for statically verifying behavioral interoperability are required. This paper contributes a method for practical, semantic verification of interoperating processes (as represented with BPMN models). We provide methods to evaluate consistency during process design where annotation of the immediate effect of tasks and sub-processes has been provided. Furthermore, some guidelines are defined against common models of inter-operation for scoping ...


Verifying Semantic Business Process Models In Inter-Operation, George Koliadis, Aditya K. Ghose May 2008

Verifying Semantic Business Process Models In Inter-Operation, George Koliadis, Aditya K. Ghose

Professor Aditya K. Ghose

Process inter-operation is characterized as cooperative interactions among loosely coupled autonomous constituents to adaptively fulfill system-wide purpose. Issues of inconsistency can be anticipated in inter-operating processes given their independent management and design. To reduce inconsistency (that may contribute to failures) effective methods for statically verifying behavioral interoperability are required. This paper contributes a method for practical, semantic verification of interoperating processes (as represented with BPMN models). We provide methods to evaluate consistency during process design where annotation of the immediate effect of tasks and sub-processes has been provided. Furthermore, some guidelines are defined against common models of inter-operation for scoping ...


Hclp Based Service Composition, Ying Guan, Aditya K. Ghose, Zheng Lu May 2008

Hclp Based Service Composition, Ying Guan, Aditya K. Ghose, Zheng Lu

Professor Aditya K. Ghose

A key impediment to the widespread adoption of web services is the relatively limited set of tools available to deal with Quality-of-Service (QoS) factors. QoS factors pose several difficult challenges in how they may be articulated. While the functional requirements of a service can be represented as predicates to be satisfied by the target system, QoS factors are effectively statements of objectives to be maximized or minimized. QoS requirements occur naturally as local specifications of preference. Dealing with QoS factors is therefore a multi-objective optimization problem. In effect, these objectives are never fully satisfied, but satisficed to varying degrees. In ...


Auditing Business Process Compliance, Aditya K. Ghose, George Koliadis May 2008

Auditing Business Process Compliance, Aditya K. Ghose, George Koliadis

Professor Aditya K. Ghose

Compliance issues impose significant management and reporting requirements upon organizations.We present an approach to enhance business process modeling notations with the capability to detect and resolve many broad compliance related issues. We provide a semantic characterization of a minimal revision strategy that helps us obtain compliant process models from models that might be initially non-compliant, in a manner that accommodates the structural and semantic dimensions of parsimoniously annotated process models. We also provide a heuristic approach to compliance resolution using a notion of compliance patterns. This allows us to partially automate compliance resolution, leading to reduced levels of analyst ...


Using Constraint Hierarchies To Support Qos-Guided Service Composition, Ying Guan, Aditya K. Ghose, Zheng Lu May 2008

Using Constraint Hierarchies To Support Qos-Guided Service Composition, Ying Guan, Aditya K. Ghose, Zheng Lu

Professor Aditya K. Ghose

A key impediment to the widespread adoption of web services is the is the relatively limited set of tools available to deal with Quality-of-Service (QoS) factors [12]. QoS factors pose several difficult challenges in how they may be articulated. While the functional requirements of a service can be represented as predicates to be satisfied by the target system, QoS factors are effectively statements of objectives to be maximized or minimized. QoS requirements occur naturally as local specifications of preference. Dealing with QoS factors is therefore a multi-objective optimization problem. In effect, these objectives are never fully satisfied, but satisficed to ...


Process Discovery From Model And Text Artefacts, Aditya K. Ghose, George Koliadis, Arthur Cheung May 2008

Process Discovery From Model And Text Artefacts, Aditya K. Ghose, George Koliadis, Arthur Cheung

Professor Aditya K. Ghose

Modeling is an important and time consuming part of the Business Process Management life-cycle. An analyst reviews existing documentation and queries relevant domain experts to construct both mental and concrete models of the domain. To aid this exercise, we propose the Rapid Business Process Discovery (R-BPD) framework and prototype tool that can query heterogeneous information resources (e.g. corporate documentation, web-content, code e.t.c.) and rapidly construct proto-models to be incrementally adjusted to correctness by an analyst. This constitutes a departure from building and constructing models toward just editing them. We believe this rapid mixed-initiative modeling will increase analyst ...


Combining Agent-Oriented Conceptual Modelling With Formal Methods, S. A. Vilkomir, Aditya K. Ghose, A. Krishna May 2008

Combining Agent-Oriented Conceptual Modelling With Formal Methods, S. A. Vilkomir, Aditya K. Ghose, A. Krishna

Professor Aditya K. Ghose

Agent-oriented conceptual modelling notations such as i* have received considerable recent attention as a useful approach to early-phase requirements engineering. Agent-oriented conceptual modelling notations are highly effective in representing requirements from an intentional stance and answering questions such as what goals exist, how key actors depend on each other and what alternatives must be considered. Formal methods such as those based on the Z notation offer a complementary set of representational facilities. We explore how these two otherwise disparate approaches might be used in a synergistic fashion.


Executable Specifications For Agent Oriented Conceptual Modelling, Y. Guan, Aditya K. Ghose May 2008

Executable Specifications For Agent Oriented Conceptual Modelling, Y. Guan, Aditya K. Ghose

Professor Aditya K. Ghose

Agent-oriented conceptual modelling (AoCM) notations such as i* have received considerable recent attention as a useful approach to early-phase requirements engineering. AoCM notations are useful in modeling organizational context and in offering high-level anthropomorphic abstractions as modeling constructs. AoCM notations such as i* help answer questions such as what goals exist, how key actors depend on each other and what alternatives must be considered. In this paper, we suggest an approach to executing i* models by translating these into set of interacting agents implemented in the 3APL language. In addition, we suggest a hybrid modeling, or co-evolution, approach in which ...


Hierarchic Decomposition In Agent Oriented Conceptual Modelling, R. B. Brown, Aditya K. Ghose May 2008

Hierarchic Decomposition In Agent Oriented Conceptual Modelling, R. B. Brown, Aditya K. Ghose

Professor Aditya K. Ghose

Software development processes requires a thorough understanding of stakeholder objectives and requirements. Product-centrism is an insufficient stance from which to achieve greater efficiencies and reduce reengineering. Stakeholder requirement elicitation is thus worthy of formalization. A suite of tools, notably the i* model, provides a framework for early-phase requirements capture. These tools currently are at best only semiautomated and essentially consist of a notational glossary and sets of mark-up symbols. Increasing formalization may lead to greater automation of the process in the future, but currently there is a degree of flexibility that presents pitfalls for the unwary practitioner. A notion of ...


Co-Evolution Of Agent Oriented Conceptual Models And Use Case Diagrams, Moshiur Bhuiyan, M. M. Zahidul Islam, Aneesh Krishna, Aditya K. Ghose May 2008

Co-Evolution Of Agent Oriented Conceptual Models And Use Case Diagrams, Moshiur Bhuiyan, M. M. Zahidul Islam, Aneesh Krishna, Aditya K. Ghose

Professor Aditya K. Ghose

Agent--oriented conceptual modeling notations such as i* represents an interesting approach for modeling early phase requirements which includes organizational contexts, stakeholder intentions and rationale. On the other hand Use Case diagram is used for capturing functional requirements of the system. The integration of i* model and Use Case diagram closes the gap of capturing organizational requirements and system requirements. But in both contexts the requirements might change at any time. Any change made in one model must be reflected in the other. This paper proposes a methodology supporting the co-evolution of these two otherwise disparate approaches in a synergistic fashion.


Co-Evolution Of Agent-Oriented Conceptual Models And Caso Agent Programs, A. Dasgupta, Aneesh Krishna, Aditya K. Ghose May 2008

Co-Evolution Of Agent-Oriented Conceptual Models And Caso Agent Programs, A. Dasgupta, Aneesh Krishna, Aditya K. Ghose

Professor Aditya K. Ghose

Agent-Oriented conceptual modelling notations are highly effective in representing requirements from an intentional stance and answering questions such as what goals exist, how key actors depend on each other and what alternatives must be considered. In this paper, we suggest an approach to executing i* models by translating these into set of interacting agents implemented in the CASO language. In addition, we suggest a hybrid modelling, or co-evolution, approach in which i* models and CASO agent programs are concurrently maintained and updated, while retaining some modicum of loose consistency between the two. This allows us to benefit from the complementary ...


A Combined Approach For Supporting The Business Process Model Lifecycle, George Koliadis, Aleksander Vranesevic, Moshiur Bhuiyan, Aneesh Krishna, Aditya K. Ghose May 2008

A Combined Approach For Supporting The Business Process Model Lifecycle, George Koliadis, Aleksander Vranesevic, Moshiur Bhuiyan, Aneesh Krishna, Aditya K. Ghose

Professor Aditya K. Ghose

Business processes evolve throughout their lifecycle of change. Business Process Modeling (BPM2) notations such as BPMN are used to effectively conceptualize and communicate important process characteristics to relevant stakeholders. Agent-oriented conceptual modeling notations, such as i*, effectively capture and communicate organizational context. In this paper we argue that the management of change throughout the business process model lifecycle can be more effectively supported by combining notations. In particular, we identify two potential sources of process change, one occurring within the organizational context and the other within the operational context. As such the focus in this paper is on the co-evolution ...


Criteria On Utility Designing Of Convex Optimization In Fdma Networks, Zheng Sun, Wenjun Xu, Zhiqiang He, Kai Niu Apr 2008

Criteria On Utility Designing Of Convex Optimization In Fdma Networks, Zheng Sun, Wenjun Xu, Zhiqiang He, Kai Niu

Zheng Sun

In this paper, we investigate the network utility maximization problem in FDMA systems. We summarize with a suite of criteria on designing utility functions so as to achieve the global optimization convex. After proposing the general form of the utility functions, we present examples of commonly used utility function forms that are consistent with the criteria proposed in this paper, which include the well-known proportional fairness function and the sigmoidal-like functions. In the second part of this paper, we use numerical results to demonstrate a case study based on the criteria mentioned above, which deals with the subcarrier scheduling problem ...


Diagnosing Faults In Electrical Power Systems Of Spacecraft And Aircraft, Ole J. Mengshoel, Adnan Darwichse, Keith Cascio, Mark Chavira, Scott Poll, Serdar Uckun Dec 2007

Diagnosing Faults In Electrical Power Systems Of Spacecraft And Aircraft, Ole J. Mengshoel, Adnan Darwichse, Keith Cascio, Mark Chavira, Scott Poll, Serdar Uckun

Ole J Mengshoel

Electrical power systems play a critical role in spacecraft and aircraft. This paper discusses our development of a diagnostic capability for an electrical power system testbed, ADAPT, using probalistic techniques. In the context of ADAPT, we present two challenges, regarding modelling and real-time performance, often encountered in real-world diagnostic applications. To meet the modelling challenge, we discuss our novel high-level specification language which supports auto-generation of Bayesian networks. To meet the real-time challenge, we compile Bayesian networks intro arithmetic circuits. Arithmetic circuits typically have small footprints and are optimized for the real-time avionics systems found in spacecraft and aircraft. Using ...