.Computers in Industry 36 1998 8393
Architecture of a multimedia communication system for technicaldocumentation in a modern factory
Constantine A. Papandreou a,), Dionisis X. Adamopoulos b,1a ( )Training and Research Centre, Hellenic Telecommunications Organisation OTE , 17 Kalliga Street, GR-114 73 Athens, Greece
b Centre for Satellite Engineering Research, Department of Electronic and Electrical Engineering, Uniersity of Surrey, Surrey, UK
This paper examines the influence of multimedia communication services and electronic document systems in themanagement of technical documentation within a modern factory. After a brief introduction in Computer-Integrated
.Manufacturing CIM and multimedia communication systems, the role of technical documentation in a CIM environment is .examined, and the architecture of a Distributed Multimedia Electronic Document System DMEDS is proposed. The basic
featuresroperations and the constituent parts of the proposed DMEDS are then analysed. Two of them, the networkinfrastructure and the necessary software structure, are examined in considerable detail. Finally, a number of importantdesign issues are addressed, and some conclusions are drawn. q 1998 Elsevier Science B.V. All rights reserved.
Keywords: Multimedia communications; CIM; Electronic document systems; Technical documentation
Manufacturing organisations are under intensecompetitive pressures as they experience majorchanges with respect to resources, markets, manufac-
w xturing processes, and product strategies 1 . As aresult of international competition, only the mostproductive and cost-effective industries will survive.
Manufacturing industries are thus faced with theneed to optimise the way in which they function inorder to achieve the best possible performance within
) Corresponding author. Tel.: q30-1- 6440924, 6854899,. .6114041 ; fax: q 30-1- 6830699, 6842671 ; e-mail:
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necessary constraints. This is a difficult task, both interms of understanding the nature of the problem andthe most effective solution strategies, and in formingand implementing plans that develop from this un-derstanding.
Many of the efforts in this direction are focusing .in Computer-Integrated Manufacturing CIM . CIM,
combined with new technologies, such as multime-dia, can provide the appropriate conceptual frame-work that will enable manufacturing organisations torespond effectively to situations associated with thedifficult environment in which they operate. Onesuch situation of significant importance appears inthe management of technical documentation in amodern factory and is examined in this paper byproposing an architecture for a Distributed Multime-
.dia Electronic Document System DMEDS for thispurpose.
0166-3615r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. .PII S0166-3615 97 00101-2
( )C.A. Papandreou, D.X. AdamopoulosrComputers in Industry 36 1998 839384
2. Multimedia and CIM
CIM is a management philosophy which involvesthe design or redesign of an entire manufacturingenterprise so that all aspects of the system worktogether effectively. In the context of CIM, the func-tions of design and manufacturing are rationalisedand coordinated using computer, communication, and
w xinformation technologies 2 . Thus, the entire manu-facturing system, from product definition and rawmaterial acquisition to the disposition of the finalproduct, is carefully analysed such that every opera-tion and element can be designed to contribute in themost efficient and effective way to the achievement
w xof clearly enunciated goals of the enterprise 3 .It should be noted that CIM is not a specific
technology that can be purchased. Rather, CIM is astrategic goal that a factory strives to achieve over
w xtime 4,2,5 . The term integrated should possiblybe changed to integrative, because in a CIM envi-ronment, all processes are involved in a continuallyevolving integrative process. Nevertheless, CIM is,because of its potential benefits, a very important
w xphilosophy for every modern factory 2 .In the framework of CIM, many new technologies
can be utilised. One of these technologies is multi-media technology.
Multimedia is a term with many different defini-w xtions 6 . One of them that is widely accepted defines
multimedia as the computer controlled integration ofdifferent basic information types where the informa-tion can be transmitted, processed, and represented
w xdigitally 7 . This definition refers to some basicinformation types, which include data, text, vector
graphics, pixel-oriented images, video signals mov-. .ing pictures , and audio signals voice and sound . It
also encompasses the three key elements in realisingmultimedia solutions: communications networks .transmission, switching , computing end stations . processing , and applications software representa-
.tion . From the definition of multimedia, it is quiteevident that multimedia is not a pure and self-con-tained technology or a toolrapplication in its ownright. Multimedia is rather a set of enabling tech-
w xnologies 8 .A multimedia system or a multimedia information
system is a system which enables the user to create,edit, transmit, receive, store, retrieve, compute, and
delete multiple types of information in an integratedw xmanner 9 . It must be noted that multimedia systems
require synchronisation of some of the informationtypes in communication, processing and presenta-tion, and in the longer term, will be characterised bythe completely digital integration of all informationtypes. Multimedia systems can be categorised mainlyto standalone multimedia systems and to multimedia
communication systems or distributed multimedia. w xsystems 10,9 .
In standalone multimedia systems, which are incommon use today, multimedia information is stored
for playback in suitable storage media most com-.monly CD-ROMs . Characteristic example of such
systems are the multimedia kiosks, used as Point Of . .Sale POS or Point Of Information POI systems. It
must be noted that the fact that these systems arestandalone does not limit their interactivity with the
user especially if a suitable Personal Computer is.used as the main hardware platform .
Several standalone multimedia systems connectedtogether via telecommunication networks form thebasis of multimedia communication systems. Thesesystems usually incorporate a central database, andtheir operation is based on the use of multimedia
w xcommunication services 8 . In this way, informationcan be updated quickly, and the system can evolve tocover the needs of its users in the best possible way,because it can collect information about how it isbeing used. Thus, multimedia communication sys-
tems can realise the true benefit of multimedia in-creased productivity, improved efficiency and effec-
.tiveness , and for this reason one application of themin the CIM environment will be examined in thispaper.
3. Multimedia technical documentation in a CIMenvironment
The activities which are performed in a modernfactory can be hierarchically grouped according tocertain features they have in common. A hierarchicaldifferentiation implies a layer-type representation inwhich the activities are carried out in the form ofservices required by a higher layer in the hierarchyfrom the next layer down. The most common hierar-chical structure of the various layers of management
( )C.A. Papandreou, D.X. AdamopoulosrComputers in Industry 36 1998 8393 85
and control information in a modern factory can beseen in the model of Fig. 1.
A typical grouping of the activities from whichthe model of Fig. 1 is comprised leads to 12 mainactivities: plant management, financial management,sales and marketing, research and development,product planning and production engineering, pro-duction management, supply, delivery, treatment ofwaste materials, resource management, maintenance,
w xand shop floor production 11 . The first 11 activitiesform the context of the shop floor production activityand are located in the Enterprise and the
.FacilityrPlant layers Fig. 1 .Information flow in the model of Fig. 1 occurs,
either between adjacent layers, in the form of servicerequests and reports on the execution of these re-quests or within a single layer, in the form ofcommunication between separate activities belonging
to the same layer. The flow of information i.e.,.communication is both vertical and horizontal. Ver-
tical flow is either downwards, in which case itcorresponds to the request made by a hierarchicallyhigher layer for a service to be provided by a lowerlayer, or upwards, in which case it is a report oncurrent status sent by a lower layer to its immediatesuperior. On the other hand, horizontal flow corre-sponds to communications within a single layer be-tween peer activities.
The information transmitted inside the model of .Fig. 1 in one layer or among several layers is
considered to be mostly technical documentation, .which can take the form among others of Com-
.puter-Aided Design CAD drawings, photographs,product and customer specifications, operations andmaintenance manuals, competition data, funds mar-ket data, parts lists, schematics, computer listings,rework instructions, video scenes of shop floor oper-ations, blueprints, and vendor manuals.
The effective and efficient management of techni-cal documentation is very important in a modernfactory, as studies have shown that as much as 90%
w xof part costs are related to documentation 2 , andbecause it is a prerequisite for the successful applica-tion of configuration management in a CIM environ-ment.
Configuration management is the definition andcommunication of the form and function of a com-pleted entity and the control and incorporation of
w xchanges to that entity throughout its life cycle 12 .An entity can be an engineering design, a softwareprogram, a strategy, or a product. The objective ofconfiguration management is first to describe clearlywhat end result is desired and then control changesthat are made in the means to obtain this end result.Thus, configuration management is an extremelyimportant function within a manufacturing company.
The four main functions of configuration manage-ment are definition, communication, control of
w xchanges, and incorporation of changes 2,12 . Therole of technical documentation management in thelast three of these functions is vital. Effective com-munication requires a mechanism that ensures theintegrity of technical documentation. Furthermore,change control and incorporation demands that tech-
Fig. 1. Layered model of a modern factory and the typical grouping of manufacturing activities.
( )C.A. Papandreou, D.X. AdamopoulosrComputers in Industry 36 1998 839386
nical documents changes must be synchronised. Asproduct traceability requirements increase, the asso-ciated demands for technical documentation manage-ment increase significantly.
4. Proposed architecture for a DMEDS
From the previous section, it is evident that thetechnical documentation utilised in a modern factoryhas a multimedia nature, in the sense that it encom-passes documents containing data, text, graphics,video, voice, sound, or a combination of these infor-mation types. It is also evident that it has to be usedin a distributed manner as it covers the completehierarchical structure of the factory.
For this reason, for the effective and efficientmanagement of technical documentation in a modern
.factory or even a number of cooperating factories ,a multimedia communication system in the form of aDMEDS is proposed. This system will ensure thattechnical documentation is produced and updatedreliably, and delivered to the right place, to the rightperson, at the right time, and in the right format.
The basic featuresroperations of the proposedDMEDS, which can be seen in the layered model ofFig. 2, are discussed below.
.1 Image capturing. It encompasses the digitalencoding of the various types of technical documen-tation. The result is a digital replica of the document,which can be displayed on a computer screen. Inputdevices for image capture include scanners, digitalcameras, and video recorders. Scanners and digitalcameras input images directly into an application.
Fig. 2. Layered model of the basic featuresroperations of theproposed DMEDS.
Input from video recorders must be passed throughspecial video boards known as frame grabbers. It
.must be noted that editing software tools allow thescanned items to be appropriately sized and cropped.
.2 Indexing. Scanned documents can be indexed .by key word s , to facilitate retrieval from the image-
base. A number of indexing systems can be devised,according to the needs of the specific company. Theindex can include key words found in the documentitself, after it has been scanned with Optical Charac-
.ter Recognition OCR software. Entire documentscan also be indexed by product, part number, topic,department or division. In addition to indexing, doc-uments can be customised with notes. Each user whoaccesses the document can append comments, ques-tions, and instructions to the file, so that furtheraction can be taken in processing the transaction.Other documents can also be appended, building acase file.
Documents do not have to be indexed individuallyor on a discretionary basis. A number of documentscan be indexed together in a process called batchindexing. With batch indexing, a number of docu-ments are collected in an electronic version of anin-basket for processing according to predefined in-dexing rules. This speeds up the indexing processand eliminates the confusion that can result fromindividual indexing preferences. Once a document isproperly indexed, individuals are allowed to cus-tomise it with preferred key words that will aid
w xsearch and retrieval and to append notes 13 . .3 Compression. Because multimedia technical
documents are much larger than ordinary text orbinary files, the proposed DMEDS has to supportone or more compression schemes. These schemes
are based on compression algorithms implemented.either in software or in hardware , which allow
image files to be shrunk by a ratio of at least 2:1and as high as 100:1 without any loss of image
.quality lossless compression . Further compression .ratios up to 250:1 result in a slight loss of image .quality lossy compression . The most important
compression standards are JPEG Joint Photographic. Experts Group with compression ratio 15:1 full
. colour still-frame applications , H.261 px64 videocoderrdecoder for audiovisual services at px64
.Kbps with compression ratio 100:1 to 2000:1 .video-based telecommunications , and MPEG
( )C.A. Papandreou, D.X. AdamopoulosrComputers in Industry 36 1998 8393 87
.Moving Pictures Experts Group with compression . w xratio 200:1 motion-intensive applications 14,10 .