3166137
Integrating Temporal Logics
In this paper, we study the predicative semantics of different temporal logics and the relationships between them. We use a notation called generic composition to simplify the manipulation of predicates. The modalities of possibility and necessity become generic composition and its inverse of converse respectively. The relationships between different temporal logics are also characterised as such modalities. Formal reasoning is carried out at the level of predicative semantics and supported by the higher-level laws of generic composition and its inverse. Various temporal domains are unified under a notion called resource cumulation. Temporal logics based on these temporal domains can be readily defined, and their axioms identified. The formalism provides a framework in which human experience about system development can be formalised as refinement laws. The approach is demonstrated in the transformation from Duration Calculus to Temporal Logic of Actions. A number of common design patterns are studied. The refinement laws identified are then applied to the case study of water pump controlling.
7323063
rCOS: Refinement of Component and Object Systems
We present a model of object-oriented and component-based refinement. For object-orientation, the model is class-based and refinement is about correct changes in the structure, methods of classes and the main program, rather than changes in the behaviour of individual objects. This allows us to prove refinement laws for both high level design patterns and low level refactoring. For component-based development, we focus on the separation of concerns of interface and functional contracts, leaving refinement of interaction protocols in future work. The model supports the specification of these aspects at different levels of abstractions and their consistency. 
 
Based on the semantics, we also provide a general definitional approach to defining different relational semantic models with different features and constraints.
5135154
Linking UML models of design and requirement
Both a UML model of requirement and a UML model of a design are defined as a pair of class diagram and a family of sequence diagrams. We then give an unified semantics for models of requirements and designs. We define the consistency between a design class diagram and the interaction diagrams and show how the removal of inconsistency can be treated as a model refinement. We then formally define the correctness of UML model of design with respect to the model of requirement.
16560725
rCOS: A refinement calculus of object systems
This article presents a mathematical characterization of object-oriented concepts by defining an observation-oriented semantics for a relational object-based language with a rich variety of features including subtypes, visibility, inheritance, type casting, dynamic binding and polymorphism. The language can be used to specify object-oriented designs as well as programs. We present a calculus that supports both structural and behavioural refinement of object-oriented designs. The design calculus is based on the predicate logic in Hoare and He's Unifying Theories of Programming (UTP).
14189544
Verification, refinement and scheduling of real-time programs
Abstract A real-time program can be developed by refining a specification into program code. Verification of the timing properties of the program is then usually done at two levels: verification of the ordering of timed actions in the program and proof that execution of the program on a specific system will meet its timing requirements. Refinement is done within a formal model but the second step requires a different framework in which scheduling theory analysis is used and actual program execution times can be taken into account. The implementation of a program on a system is said to be feasible or schedulable if it will meet all the timing deadlines. This paper shows how the feasibility of scheduling a real-time program can also be proved as a step in the refinement of the program from its specification. Verification of this step of refinement makes use of methods from scheduling theory within a formal system development framework.
39997807
Component-Based Software Engineering
We discuss some of the difficulties and significant issues that we need to consider when developing a formal method for component-based software engineering. We argue that to deal with the challenges, there is a need in research to link existing theories and methods of programming for effective support to component-based software engineering. We then present our initiative on a unified multi-view approach to modelling, design and analysis of component systems, emphasising the integration of models for different views.
2458786
High Performance Embedded Route Lookup Coprocessor for Network Processors
Embedded Route Lookup Coprocessors (RLCs) are attractive for their potential in building high-performance Network Processors. But compared with conventional lookup schemes, it always imposes more severe restrictions on table size and power consumption, which poses challenge in the state of art. In this paper, we propose a novel lookup mechanism, Compounded CAM with Optimized Bitmap Compression (CCAM-OBC), which employs different lookup methods for prefixes of different length ranges, so as to combine the benefits of CAMs and bitmap compressed tries. With this scheme, table size, power consumption and update complexity are all well optimized while very high lookup throughput is achieved, which makes it a perfect solution to embedded RLC. For a real-life 130K-prefix route table, the implemented prototype performs more than 100 Million Packets Per Second (MPPS) with only 24KB TCAM, 48KB BCAM and 251KB SRAM. Furthermore, each update needs only 2 memory accesses averagely.
16274304
Face detection and tracking in video using dynamic programming
Face detection and tracking are important in video content analysis since the most important objects in most video are human beings. This paper proposes a new approach for combined face detection and tracking in video. The face detection algorithm is a fast template matching procedure using iterative dynamic programming (DP). Although the face detection algorithm is designed for frontal face, the same mechanism can also be applied to track non-frontal faces with online adapted face models. Due to the essence of template matching, the algorithm is capable of comparing the similarity among different faces, which makes it suitable for tracking the same face that occur at disjointed temporal locations in video. While the proposed face detection method provides comparable accuracy as the neural network based approach, it is much faster.
31153136
An Adaptive Scheduling Algorithm for Molecule Docking Design on Grid
Grid provides a promising platform for the efficient execution of drug molecular docking design. Scheduling such applications is challenging for the heterogeneity, autonomy, and dynamic adaptability of grid resources. Assuming resource owners have a preemptive priority, we propose an adaptive algorithm of jobs scheduling based on time balancing strategy, which solves parallel molecular docking task by using the idle resources in the Grid. A mathematical model is developed to predict performance, which also considers systems with heterogeneous machine utilization and heterogeneous service distribution. According to the time balancing policy, ligands are partitioned into several subtasks and scheduled. The expected value of molecular docking completion time is predicted with performance model. To get better parallel computing performance, an optimal subset of heterogeneous resources with the shortest parallel executing time of tasks can be selected with the algorithm.
14922920
A dynamic trust model for mobile ad hoc networks
This paper introduces a trust model for mobile ad hoc networks. Initially each node is assigned a trust level. Then we use several approaches to dynamically update trust levels by using reports from threat detection tools, such as intrusion detection systems (IDS), located on all nodes in the network. The nodes neighboring to a node exhibiting suspicious behavior initiate trust reports. These trust reports are propagated through the network using one of our proposed methods. A source node can use the trust levels it establishes for other nodes to evaluate the security of routes to destination nodes. Using these trust levels as a guide, the source node can then select a route that meets the security requirements of the message to be transmitted. This paper demonstrates important concepts for establishing a collaborative, dynamic trust model and for using this model as an example to enhance the security of message routing in mobile ad hoc networks.
34520117
Print vs. electronic resources: A study of user perceptions, preferences, and use
The arrival and proliferation of electronic resources and digital libraries have a number of significant impacts on the use of print resources and traditional libraries. This study explores the extent to which graduate students in a metropolitan university setting use print and electronic resources. Reading preferences and use of print and electronic resources vary among different disciplines. Graduate students seem to expect a hybrid of print and electronic resources. They desire to meet their information needs through a mix of print and online resources, even though reasons for supplementing another type of resource differ. Circumstances that affect the selection of use between digital libraries and traditional libraries are also discussed.