George A. Papadopoulos, Farhad Arbab.
Coordination Models and Languages.
Advances in Computers,
Vol. 46,
pages 330-401,
1998.
Abstract:A new class of models, formalisms and mechanisms has
recently evolved for describing concurrent and
distributed computations based on the concept of
"coordination". The purpose of a coordination model
and associated language is to provide a means of
integrating a number of possibly heterogeneous
components together, by interfacing with each
component in such a way that the collective set
forms a single application that can execute on and
take advantage of parallel and distributed
systems. In this chapter we initially define and
present in sufficient detail the fundamental
concepts of what constitutes a coordination model or
language. We then go on to classify these models and
languages as either "data-driven" or
"control-driven" (also called "process-" or
"task-oriented"). Next, the main existing
coordination models and languages are described in
sufficient detail to let the reader appreciate their
features and put them into perspective with respect
to each other. The chapter ends with a discussion
comparing the various models and some conclusions.
Technical Reports and Manuals:
Svend Frolund, Jari Koistinen.
QML: A Language for Quality of Service Specification.
Num. HPL-98-10,
63 pages,
HP Laboratories,
1998.
Abstract:To be competitive, future software system must provide not
only the correct functionality, but also an adequate
level of quality of service (QoS). By QoS, we refer
to non-functional properties, such as reliability,
performance, timing, and security. To provide an
adequate level of QoS, software systems need to
include capabilities such as QoS negotiation,
monitoring, and adaptation. These capabilities all
require the expected and the provided QoS levels to
be explicitly specified. QoS can be specified
statically at the time of implementation, design, or
dynamically at deployment or runtime. To facilitate
QoS specification, we present a general Quality of
service Modeling Language (QML) for defining
multi-category QoS specifications for components in
distributed object systems. QML is designed to
support QoS in general, encompassing QoS categories
such as reliability, performance, security, and
timing. QoS specification in QML facilitate the
static decomposition of a software system into
components with precisely specified QoS
boundaries. They also facilitate dynamic QoS
functions, such as negotiations, monitoring, and
adaptation. QML is designed for a good fit with
object-oriented distributed architectures and
concepts such as interfaces and inheritance. It also
allows specification at a fine-grained level for
operations, operation arguments, and attributes. QML
enables user- defined QoS categories, and allows
specifications within those categories to be
associated with component interface definitions. In
addition, checks can be made dynamically to
determine whether one QML specification satisfies
another. This mechanism allows us to dynamically
match QoS requirements and offers
