COMBINE 2: Project Up-date
COMBINE 2: Project Up-date
(November 1994)
Contents:
Task 1: Specification
Task 2: Concept Design
Task 3: Data Exchange System Development
Task 4: Integrated Building design System Development
Task 5: Actor Interaction Handler Development
Task 6: Acceptance Testing and Dissemination
The system specification task is now complete. The objective of task 1 was to arrive at a
specification of the proposed design system's functionality which would:
- satisfy the project's stated objectives
- lead to systems which could perform useful real world design functions and
be capable of being introduced into test sites
- be capable of being realistically implemented given the time and resources available to the project
The task was undertaken in several stages.
- COMBINE 2 partners approached selected architectural and building services design firms to
determine if they would be willing to become test sites for the COMBINE system.
- A questionnaire on work practices within the co-operating organisations was drawn
up by the task leader UCG and administered by the COMBINE 2 partners.
- The results were analysed together with the organisations descriptions of their tools
and a report produced for the second COMBINE 2 project meeting (M2) in May 1993 in Galway, Ireland.
- This report was commented on and a further task meeting was held. As a result, a second
and final report was presented at the third project meeting (M3) in October 1993 at
Newcastle-upon-Tyne, UK.
One issue which had not been satisfactorily resolved by M3 was that of modelling the
flow of control in the design systems. A variety of approaches were explored including
IDEF0, Jackson diagrams and various object-oriented modelling languages. Eventually,
Technical University Delft came up with a formalism loosely based on Petri-Nets, named
Combi-Nets, which answered the need. The output of Task 1, namely the specification and
the Combi-Net models, are now being used by Tasks 3 and 4 to guide their design and
implementation work.
TASK LEADER: University College Galway, Ireland
Within this Task 2, conceptual modelling activities have been continuing at the three initial levels:
- Design Tool (DT)-level
- Integrated Data Model (IDM)-level
- Integrated Building Design System (IBDS)-level
DT-level
At the DT-level, DT suppliers have produced Aspect Models, conceptual models
of their tool, using the ATLIAM editor. They are currently working on IDM
subschemas, subsets of the Integrated Data Model, and on Mapping Tables,
which describe the mapping between Aspect Model and Subschema.
IDM-level
At the IDM-level, current work concentrates on finalizing the
so-called IDM+, an improved version of the COMBINE 1 IDM without scope
extensions. An IDM+ subset was delivered by TNO-CIC in December 1993,
describing models for spaces and enclosing structures and for geometry and
topology. A draft version for space function was delivered by CSTB in February
1994. The remaining parts, dealing with site data, technical systems and
performance data, are expected shortly. After completion of the IDM+,
the model will be extended in scope and address issues such as the relationship
between building and HVAC systems, building requirements, performance
semantics and library structures.
IBDS-level
At the IBDS-level, dynamic aspects (or behaviour aspects) of product information
is modelled. TU Delft has developed a Project Window modelling approach which
currently serves as a baseline for IBDS modelling. In this approach three control
levels are distinguished:
- no control at all
- shallow control, and
- deep control
Level 1 represents the way in which COMBINE 1 dealt with product information flows.
At level 2, control is limited to monitoring the sequence of events. UCG is working on
two Project Window models aiming at this level. At level 3, control is extended to
pre and post-conditions, meaning and purpose of activities, etc. This level is aimed
at in a limited prototype in Task 5.
TASK LEADER: TNO-Computer Integrated Construction, The Netherlands
This is a brief description of the current status of the Task 3 work on the Data Exchange System
(DES) Kernel and its interfaces. The system structure of the DES comprises four components;
- Data Exchange Kernel (DEK)
- Off-Line Data Interaction Manager (DIMOFF)
- On-Line Data Interaction Manager (DIMON)
- Data Exchange Toolkit (DET)
- Exchange Executive (ExEx)
This holds a representation of one or more buildings that is shared by many different
design tools. Considerable progress has been made on implementing the DEK. At the core
of the DEK is an implementation of the ISO STEP part 22 SDAI n350 information model.
All three SDAI schemas of this model have been implemented. These include the data dictionary
schema, the session schema and the abstract data type schema. All building instances are held
in the DEK in meta-representation (the structure of the model is stored as data); this allows the
DEK to support multiple schemas and multiple views of the data.
The DEK has been implemented on top of a commercial object oriented database, ObjectStore
and runs on UNIX and Windows platforms.
Off-Line Data Interaction Manager
The role of the DIMOFF is to provide an interface for design tools that exchange data with the
DEK used by ISO STEP part 21 physical files. At present, data can be imported and exported,
to and from, the DEK in accordance with the IDM schema. Work is currently underway to extend
this facility to support exchange in accordance with sub-schemas of the IDM. In the present version
a DIMOFF must be configured for each design tool for import functionality, although future
versions will be generic for any design tool. Export is currently generic for any design tool.
On-Line Data Interaction Manager
The DIMON supports tools which can work interactively with the DEK; in particular, CAD tools which
must exchange data with the DEK as the user works on the building design. It holds an early bound data
model of the IDM in accordance with the C++ language definition and at present provides an interface
with the DEK that allows the exchange of geometric and topological entities.
Versions of the DIMON are being configured to interact with both Microstation CAD and AutoCAD.
Data Exchange Toolkit
The DET provides the facility for off-line design tools to build interfaces onto the ISO STEP part
21 physical files produced by the DIMOFF. The DES-independent interface kit (IntKit) comprises
an EXPRESS language parser, an SDAI implementation, a textual browser and a graphical browser.
At present a first version of the interface kit is available, it supports the SDAI C++ functional
binding specification.
Exchange Executive
The Exchange Executive (ExEx) is designed to be the IBDS-component that manages and
monitors the flow of control over the sequence of design tool invocations. It has embedded
in it shallow knowledge of the design process inside a Project Window (PW). For the process
model, a special modelling method (CombiNet) is developed. The ExEx takes the project window
descriptions and the input and output EXPRESS schema of a Design Tool and configures itself from
these definitions. The CombiNet can then be evaluated by the ExEx. Future work lies in integrating
the ExEx with the DES.
TASK LEADER: University of Newcastle, United Kingdom
Task 4 is entrusted with the responsibility of producing two of the three integrated building
design systems which are to be created and subjected to field test and evaluation by the COMBINE project.
System 1
The first of the systems will be aimed at architectural practice. It will be
constructed by taking the Intergraph based architectural CAD tool being developed by
Technical University Delft and linking it by means of the Data Exchange Kernel and the
On and Off line Data Interaction Managers (see Task 3 section of this newsletter for details)
to the following applications:
- Building Regulations Compliance Checker
- U-Value Checker
- Average Daylight Factor
- Condensation Risk Evaluator
- BREEZE/BREAIR (infiltration and ventilation calculator)
- CEN summer overheating risk calculator
- prEN832-Calculation of Energy Use for Heating - Residential
- Building Annual Energy Consumption Calculator
- Building Components Database
- Costing Tool
- DocLinks (Document management system)
All these applications will have data exchange interfaces for communicating
their inputs and outputs to the Off-line data interaction manager. These interfaces
will be built using the Data Exchange Toolkit. The Task 4 team leader, CATERU -
University College Galway, has responsibility for overseeing the production of these
interfaces and providing the development teams with the data files which will be used
to test the interfaces before the availability of the completed system. The operation
of all these tools will be controlled by an "Exchange Executive" (see Task 3) specially
configured for the system. The job of the exchange executive is twofold:
- After each tool places data into the kernel, it must determine which tools are
permitted to operate next. This helps to maintain the consistency of the design
data in the kernel.
- To determine which tools need to be re-run as a result of the changes just made.
The operation of the Exchange Executive is controlled by a Petri-Net like
model (Combi-Net) called a "Project Window".
System 2
The second system is aimed at building services engineers and is designed to assist them in their
design work. This system is similar to the first except in that it contains a number of different
tools, and the control model loaded into its Exchange Executive is necessarily different.
As before, the system is based around a CAD tool - an AutoCAD based HVAC ductwork CAD
package being developed by CATERU - University College Galway, linked in the same manner
as before to the following applications:
- Superlink - lighting design
- tsbi3 - detailed thermal simulation tool
- ESP-r detailed thermal simulation tool
- HVAC CAD Design Tool
- DOE-2DX loads - detailed thermal simulation tool
- VENT duct sizing program
- Cost Evaluator
- HVAC components database
- DocLinks - document management system
TASK LEADER: University College Galway, Ireland
Task 5 is concerned with the construction of a knowledge-based design tool interaction handler
or IIBDS (intelligent, integrated building design system). The intention is that the IIBDS will
coordinate designer-to-designer, designer-to-application and application-to-application transactions,
against rules which describe the purpose of a given design session.
At the present time, this work is addressing the 'shallow' control issues relating to
design tool sequencing and interaction. This includes both user-to-user (e.g. cooperative working)
and user-to-design tool (e.g. user decisions on design tool sequencing) transactions.
In the near future the focus will shift to the issue of 'deep' control where knowledge is introduced
in relation to design purpose so that design tool use is constrained within a specific design session.
For example, if a comfort assessment design tool returned "warm_uncomfortable", while a lighting
tool returned "inadequate_daylighting", then some inferred constraint may be placed on the permissible
modifications to the fenestration.
Within Task 5 a rapid prototyping approach is being employed by which the different possibilities
for transaction handling are being examined and the outcome used to drive IIBDS evolution.
To direct this line of enquiry, a Project Window (PW) has been elaborated which comprises
several design tools chosen to offer significant design appraisal capabilities while representing
a realistic mix of interactions.
The PW incorporates the management of design tools for CAD, energy, lighting and constructional
compliance against the following storyboard:
- On entering the PW an architectural CAD package (here AutoCAD) is invoked for use
to define the geometry of any portion of a multi-zone building problem.
- On exiting the CAD package, an attribution tool is invoked (here the Project Manager module of ESP-r)
to attribute this geometry in relation to construction, occupancy, control and climate. Within the COMBINE
system data exchanges between design tools are enabled by an Integrated Data Model (see Task 2) as
encapsulated within a Data Exchange System (DES - see Task 3). Because the DES is only now
becoming robust, the current IIBDS prototype achieves its data exchanges via a DES-emulator which operates
on the basis of conventional data filters.
- As the constructional definition of each room is completed, a U-value Checker is invoked to advise
on compliance.
- Upon completion of problem attribution, the user can either request
an energy and/or lighting analysis, or return to the CAD tool to change the problem geometry.
- ESP-r's Simulator is included to enable three performance evaluations at the present time:
summer overheating potential, winter heating plant sizing and heating energy requirement estimation.
- RADIANCE is included to enable the quantification of a zone's natural illumination levels and the
production of visual impact information at the building level.
- On completion of a performance evaluation, the design can be modified or the PW exited.
To construct the IIBDS, various technologies are being harnessed, including a central
'Blackboard' to store the various transactions and transmit these onwards to the clients
on a need-to-know basis. Two of these clients, concerned with user and design tool
knowledge handling, operate on the basis of an automatic translation of Petri Networks
to Prolog Predicates. This means that design tool sequencing, and knowledge relating to
design intent, can be introduced without any modifications to the IIBDS. The next stage is
to use this facility to introduce design knowledge so that the scope of the design tools
can be controlled as a function of the evolving state of the design and its changing performance.
TASK LEADER: ESRU-University of Strathclyde, United Kingdom
The activities of Task 6 have begun to expand since the last newsletter. Present activities include:
The dissemination of information to interested parties continues with this, the second newsletter.
Newsletter No. 3 will be available around Christmas.
A full colour brochure giving an outline of what the project is about is also to be published
which aims to inform a more general audience in the engineering and architectural world of
COMBINE. All those on the present distribution list will receive a copy automatically
Acceptance Testing
A very important part of Task 6 has also recently begun. In the final phase of the project the
delivered COMBINE system will be placed in several professional offices around Europe. A number
of commercial architectural and engineering practices have shown an interest in co-operating in carrying
out field tests of the delivered system on projects which have already been or are about to be completed.
The objective of subjecting the delivered COMBINE 2 system to acceptance testing is multi-dimensional
. The main focus will be on those functions which assist in the design process of a building project and
on the manner in which they enable the designer to optimise the building design in terms of energy,
design time and cost. Testing will encompass those functions which are directly related to the design
process and which will be used by the test site partners in undertaking the design process on their
selected buildings.
At this stage, COMBINE 2 partners who are to be involved in the acceptance testing of the delivered
COMBINE system are actively seeking support to help finance what is essentially a costly but very
necessary part of this project. UCD is also in the process of producing an Acceptance Testing Specification
which will set out guidelines by which testing of the COMBINE 2 system will be carried out. Each test
site will have individual characteristics and needs and, therefore, a specification is being created to
allow a degree of flexibility in the setting-up and the carrying-out of the testing procedure.
Acceptance testing will be scheduled for the final two months of the project, finishing around the end
of the summer 1995. A final seminar will be organised to demonstrate to those interested the
results of COMBINE 2 and to review the overall project.
TASK LEADER: Energy Research Group, University College Dublin, Ireland