There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

How to Do Things With Words

Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

Context-aware computing is a mobile computing paradigm in which applications can discover and take advantage of contextual information (such as user location, time of day, nearby people and devices, and user activity) Since it was proposed about a decade ago, many researchers have studied this topic and built several context-aware applications to demonstrate the usefulness of this new technology Context-aware applications (or the system infrastructure to support them), however, have never been widely available to everyday users In this survey of research on context-aware systems and applications, we looked in depth at the types of context used and models of context information, at systems that support collecting and disseminating context, and at applications that adapt to the changing context Through this survey, it is clear that context-aware research is an old but rich area for research The difficulties and possible solutions we outline serve as guidance for researchers hoping to make context-aware computing a reality

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A Survey of Context-Aware Mobile Computing Research

[서평]「Component Software」 - Beyond Object-Oriented Programming -

Object based architectures, such as the standardized reference model for Open Distributed Processing (ODP), must not only provide for the simple client-server styles of interaction found in data processing, but must also support the rich variety of different communication configurations and dependencies that are found in multimedia applications. To do this, ODP defines both simple two-party communication and an explicit binding model which can describe a wide range of more complex situations. It encapsulates the complexity within a visible binding object.

RIVUS: A Stream Template Language for Capturing Multimedia Requirements

Open Distributed Processing (ODP) is a joint standardisation activity of the ISO and ITU. A reference model has been defined which describes an architecture for building open distributed systems. This paper introduces the key aspects of the reference model of open distributed processing, including the ODP conformance framework. We discuss how specific formal techniques are used in the ODP viewpoints, along with the implications for conformance assessment using such techniques. Particular attention is given to the role of consistency in the conformance assessment process. Finally, we review the current work on an ODP conformance testing methodology.

The specification and conformance of ODP systems

Computer Science at Kent OCL 2.0: Implementing the Standard

In ODP, an enterprise specification is expressed in terms of the definition of some set of communities, characterized by their community contracts. A community places constraints on its members, restricting the behaviour they can participate in. This may involve a stronger form of constraint than those which result from the traditional binding of objects at interfaces, which requires only that the communication between the objects has some observable properties. This paper discusses the different forms of constraints, and examines the range of forms that community construction may take. In particular, it examines the process of abstracting from a community to yield a community object, and then using this object to fill some role in a broader community. It shows that the role filling process needs to consider mappings and constraints between objects that fill other roles in the communities concerned.

Peter F. Linington

Papers

RIVUS: A Stream Template Language for Capturing Multimedia Requirements

The specification and conformance of ODP systems

Computer Science at Kent OCL 2.0: Implementing the Standard

The Stereochemistry of Enterprise Objects

Issues in distributed systems