LYKEION nyt 8 HUSK AT der afholdes workshop om klassifikation mandag den 30. september 2002 kl. 14.30 i DANTERMcentret Bernhard Bangs Allé 17A, auditoriet på 1. Sal. INDHOLD side Anders Ekholm: Principles for classification of construction objects..2-13 Lise Borup: Klassifikation af egenskaber.. 14-36 Bjørn Bindslev: Property classification in building... 37-46 Bjørn Bindslev Klassifikation af egenskaber 47-53 Noter..54-54 LYKEIONS FORMÅL I foreningens vedtægter 2 hedder det bl.a.: Lykeion er en interesseorganisation, der arbejder på at løse nogle af de fundamentale problemer, som i praksis hindrer kommunikation indenfor og mellem parter fra forskellige fagområder, og som især manifesterer sig, når der anvendes datateknologi. Problemerne er bl.a. opstået, fordi de enkelte fagsprog i tidens løb har udviklet sig uafhængigt af hinanden uden respekt for generelle terminologiske principper og uden støtte af et hensigtsmæssigt begrebsapparat. LYKEION DANTERMcentret Bernhard Bangs Allé 17A DK-2000 Frederiksberg T: +45 38153371 Fax: +45 38153820 Websted: www.lykeion.dk Anders Ekholm Svar til Lise Borup...55-58 LYKEION nyt er et medlemsblad for foreningen LYKEION. Bladet er et uprætensiøst bidrag til at holde kontakt både indbyrdes mellem Lykeions medlemmer og mulige andre interesserede i samfundet. Der er ikke fastlagt officielle rammer for formen, indholdet, omfanget og frekvensen af bladet, men som det fremgår vil der dels være foreningsmeddelelser og dels faglige bidrag. Redaktion Bjørn Bindslev Henrikshave 25, 2950 Vedbæk Tel.: 45 891710 Mail: mofdk@get2net.dk LYKEION nyt 8.doc 1
PRINCIPLES FOR CLASSIFICATION OF CONSTRUCTION OBJECTS Anders Ekholm Abstract: This report presents a proposal for a classification of generic properties of systems and an application to construction objects. The background is a documented need for classification expressed in international construction co-operation within ISO, IFC and other standardisation efforts, to be used in different applications like classification systems and product libraries. The general property classification presented in this paper has been developed on the basis of general property theory and systems theory. It is related to a selection of earlier work in property systematic in the construction sector. The report concludes that property classification is important, but that continued work on standards for presentation of properties for construction objects must be done. Keywords Properties, attributes, classification, systems theory, construction The need for classification of properties The aim of the work presented here has been to develop a theoretical foundation for classification of properties of construction objects, i.e. construction entities like buildings and civil engineering works, parts of construction entities and construction products. The objective has been to clarify the principles for classification, not to develop attribute tables or lists for different construction objects. In every context where specification of a construction object is pertinent, e.g. in specifications for construction works, environmental declarations, product catalogues and product libraries, the need for structuring attributes occurs. The ISO Technical Report 14177 which was compiled to prepare for the international construction classification standard ISO 12006-2 (ISO 2001), states that a classification of properties is a necessary step towards a sound development of information systems (ISO 1994). In different ongoing projects within the national Swedish RTD-programme IT in Construction and Real Estate Management 2002 (IT Bygg & Fastighet) this need has also been observed (Svensson et al 2000), and Häggström et al 2001). The need for classification of properties is perhaps most evident in applications for Internet based search for construction products, where attributes are a key search variable (Engdahl 2001). In the seminar series Nordic Product Libraries organised by the Nordic IAI, the need for a common classification to be used in IFC attribute libraries and Property Sets has been discussed. Research into CAD-systems for the early stages of design suggest that such systems should be property-oriented, rather than class-oriented (Garret and Hakim 1994), Ekholm and Fridquist 1998, and Fridquist, Hendricx and Leuwen 2001). These examples all require a systematic for properties. Principles for classification 2
The theoretical background for this work is mainly based on Mario Bunge s works, primarily his Treatise on Basic Philosophy (Bunge 1974, 1977, 1979 and 1983a and 1983b). Bunge s work belongs to the realist tradition within the philosophy of science and technology, which is compatible with the, often tacit, praxis of modern science. It is chosen as a framework since it represents a model work of both consistent synthesis and consideration of diverging positions within its wide field. The next section presents the theoretical framework and a proposal for classification of properties of concrete systems. Then, a selection of earlier works on property systematic in the construction sector is analysed. Based on this, an example of a classification of properties of construction entities is developed. Finally conclusions and remaining questions are discussed. The research was financed by IT Bygg & Fastighet 2002, and Formas. Properties of objects Concrete and conceptual objects Objects are generally defined as entities, concrete or conceptual, towards which feelings, thoughts or actions are directed. Objects are characterised by their properties, but the distinction between an object and its properties is a purely conceptual operation, there are no objects without properties or vice versa (Bunge 12977:26). Conceptual objects, e.g. feelings or thoughts are mental constructs with abstract or conceptual properties (ibid:58), while non-conceptual or concrete objects, are things with concrete properties (ibid:110). Primary and secondary properties Scientists and philosophers like Galilei, Newton, Descartes and Locke distinguished between primary and secondary properties. Primary properties, e.g. velocity or mass, exist independently of an experiencing subject, while secondary properties emerge in the relation between a thing and a subject. Secondary properties are perceived through the senses, e.g. colour, intensity of sound, and shape or gestalt. Primary properties of things are here called material, while secondary properties are called cultural. See Figure 1. Properties Figure 1. Basic property types Concrete -------------Primary/Material Conceptual ----------Secondary/Cultural Objective-subjective In a somewhat widened sense, secondary properties can be understood as man s conceptions of things, (ibid:67). These include not only properties as they are perceied through our senses but also those, which are produced through reason, e.g. scientific theories. Propositions that aim at describing a thing s material properties, by certain standards independently of an observer, are called objective (Bunge 1983a:155). They can be true or false depending on their correspondence with the material properties. With increased Principles for classification 3
knowledge, previously true propositions can be considered false or in need of improvement. Propositions that aim ar describing a thing s cultural properties are subjective if they depend on an individual and inter-subjective if they are based on conventions in a social system. Subjective propositions are neither true nor false. Properties of systems The properties of a system can be divided into intrinsic and mutual (ibid:65). Examples of a system s intrinsic properties are its composition of parts and their resultant properties like mass and material, and properties that emerge in relations between the parts, e.g. density, state of aggregation, surface structure, etc., as well as intrinsic events like shrinkage, expansion, radiation, emission and decomposition. Intrinsic properties are possessed by the object alone while mutual properties emerge through relations between the system and its environment. The system s intrinsic properties are basic to its mutual properties. Bunge distinguishes between three kinds of mutual properties, which emerge in the relation between: object and environment object and reference frame object and subject Figure 2 illustrates the main categories of property presented here. Figure 2. Main categories of properties Properties in the relation object-environment A function is a mutual property based on bonding relations between a thing and its environment. Functions affect the state of the related things. Intrinsic properties are basic to functions, e.g. porosity and impenetrability to gases of a thing are prerequisites for its heat insulating function. Principles for classification 4
Properties in the relation object-reference frame A comparative property is based on a non-bonding relation between a thing and a reference frame. A reference frame is a thing that serves as a comparison concerning some property. Spatial and temporal properties, velocity, degree of temperature, hardness are examples of comparative properties. A spatial relation is defined as a non-bonding separation relation between things. Properties like length, width and height are properties relative to a spatial reference frame. Time is defined in analogue with space as a separation relation, but between events. A reference frame for time, e.g. a clock, is characterised by its regular process. Properties in the relation object-subject The mutual properties that emerge in the relation between object and subject are perceptions and interpretations of the object; they are cultural properties. Perceptions, or phenomenal properties, are active reproductions of events in the environment and the individual s body but also depend on earlier experience and ideas (Bunge 1979:154 and 1983a:35). Phenomenal properties are both subjective and objective, they are experiences of a subject but may correspond to an object s material properties. Examples of objective phenomenal properties are loudness, colour, and warmth, while comfort, beauty, and excitement, are subjective phenomenal properties. Phenomenal properties can be grouped according to the object s visual shape, colour, light, texture, tactile, and auditory properties (Hesselgren 1954). Experience of a thing does not make halt at perception, but also depends on conception or thought. A specific thought activity is interpretation. Bunge distinguishes between two different kinds of interpretation, epistemic and semiotic (Bunge 1974:1). Epistemic interpretation means that the subject through experience of the object tries to know its material properties. Therefore, epistemic properties may be objective. Epistemic interpretation is used both in everyday life and in science. The object may be described as a system, with environment, parts and relations. Semiotic interpretation means that the subject tries to know the meaning that the object conveys, seen as a sign in a communication system. Signs are interpreted as meaningful objects rather than as concrete systems. Signs may be linguistic e.g. newspapers, and books, or non-linguistic, e.g. light signals and road signs. Semiotic properties are intersubjective and based on conventions in a social system. To sum up, the properties in the object-subject relation are phenomenal properties, i.e. perceptions related to an object, epistemic properties, i.e. objective conceptions of the object s properties, and semiotic properties, i.e. meanings of objects. Qualitative and quantitative properties Properties may be qualitative or quantitative (Bunge 1977:68). A quantitative property, e.g. distance, comes in degrees while a qualitative property, e.g. load-bearing, either exists or Principles for classification 5
not exists. Quantitative properties may be represented by attributes with some value domain. Determination of properties During design, the properties of a possible artefact are determined. Phenominal properties like comfort and security can serve as a starting point for determination of functions like climate control and burglary protection. Basic to these are functions like heat resistance and locking system. Both can be represented by quantitative attributes e.g. u-value, and break-up resistance time. In their turn, these properties are based on properties of the constituent material, and durability and fastening of construction products. Classification The process of discriminating between objects results in the formation of kinds, e.g. the class of buildings or the class of ideas (Bunge 1979:165). A class concept generally refers to an object as a whole (Bunge 1974:15), while a class concept that specifically represents a property of the object is an attribute. (Bunge 1977:59). An example is the attribute v which refers to a moving object and represents its velocity. To classify is to group a collection of objects into mutually disjoint subsets for a specific purpose. The sets are ranked in a level order where sets with a higher rank include sets with a lower rank (Bunge 1983b:325). To classify properties of objects is in principle the same as to classify the objects having these properties, since the object-property dichotomy is a purely conceptual operation. A classification of concrete properties may result in a table of attributes each representing a property. Classification of properties of concrete systems Material properties Material properties of concrete systems are independent of human experience, but may be truly represented by objective conceptual knowledge. The class dividing properties in the first rank are based on the distinction between mutual properties of the system and its environment, and intrinsic properties of the system. Mutual properties are divided into those based on bonding or non-bonding relations. 1. Functional (mutual properties based on bonding relations to the environment). To this class belongs functions in relation to the environment, including side-effects and environmental effects. A function may be time dependent. 2. Comparative (mutual properties based on non-bonding relations to the environment). Comparative properties are based on non-bonding relations to reference frames, e.g. position, geometry, and temporal properties like birth date, deletion time, order, rhythm, and pace. 3. Compositional (intrinsic properties based on parts and relations among parts) Compositional properties are intrinsic to the system, e.g. material, mass, density, surface structure and intrinsic processes. The parts of the system and the larger whole which it is part of, are also characteristic of the system but these are things, and not properties of things like function and mass. Principles for classification 6
Cultural properties Cultural properties of a system are experiences and thoughts of a subject related to the system but not intended to represent the system s material properties. The properties of an individual are subjective. If they are shared by others through convention, they are intersubjective. The class dividing properties in the first rank are based on the distinction between individual perceptions and social conventions, i.e. phenomenal and semiotic properties respectively. Semiotic properties may be divided into symbolical and administrative. The former allows the system to be interpreted as a meaningful sign or a symbol for another thing, while the latter are assigned to the system for administrative reasons, e.g. for identification, naming, description or assessment. Price, the exchange value of a system, is an administrative property. 4. Phenomenal (mutual properties determined by the individual s experience) Phenomenal properties are based on the individual s experience of the system. They can be divided into objective and subjective. Examples of the former are colour, loudness and brightness, and of the latter are comfort, beauty and safety. 5. Symbolising (mutual properties based on interpretation of the system as a sign or symbol) Symbolising properties are based on semiotic interpretation of a system as a text or symbol, they are information in a communication system. The symbolising properties can be divided into linguistic or non-linguistic, books and road signs respectively have symbolising properties. 6. Administrative (mutual properties assigned to the system in an administrative context) Administrative properties are assigned to the system so that it can be identified and categorized in a social system. Examples are ID, name, classification, and price but also descriptions and property declarations. Existing systematic for properties of built objects Check lists for technical documents The investigation Kontrollistor för tekniska dokument (Check Lists for Technical Documents) is a compilation of attributes for construction entities, construction entity parts, and construction products. It is a checklist to be used in investigations of properties of construction objects. It is based on earlier Swedish and international work, e.g. the CIB Master List 1972 (Fors and Karlsson 1977). Properties are divided in two main categories. The properties in the category Functional prerequisites are mainly functions intended to be used as a basis for requirements on construction objects, e.g. in specifications. The properties in the category Properties of material and constructions are also to a large extent functions. They represent the construction entity s capacity to meet requirements and expectations by society and individuals. The difference between these types of functions is not described explicitly but Functional prerequisites are qualitative attributes and can be stated independently of a technical solution, e.g. durable, and internal climate. In contrast, functions in the category Properties of material and constructions are more specific and depend on the technical solution. They are represented by quantitative attributes. Principles for classification 7
CIB Master List 1993 The CIB Master List is the globally most well known, widespread, and applied list of properties (CIB 1993). The CIB Master List should not be regarded as a classification, since the classes are not disjoint, but as a recommendation for disposition of information in technical documentation of construction objects in the context of design, production, distribution, use, and maintenance. The main headings in the CIB Master List are: 0 Document 6 Site work 1 Identification/Brief description 7 Operation 2 Requirements 8 Maintenance, repair, replacement, disposal 3 Technical description 9 Supply 4 Performance 10 Manufacturer/Supplier 5 Design work 11 References The headings are adapted to present information for different needs. Under Document is collected information about documentation, so called meta data. Under Identification /Brief description is the product s name and short summary of functions and technical solution. Similar to the Check Lists above, the Master List distinguishes between Requirements and Performance. Under Requirements are listed functional requirements, exemplified by those of the European Construction Products Directive (Council Directive 89/106/CE 1988). Performance are functions represented by quantitative attributes. Under the heading Technical description are presented compositional properties like material. The rest of the headings describe other properties that are regarded relevant to the description of a product, e.g. in the context of delivery, asssembly, use, and maintenance. The content under these headings is of a descriptive and advisory character, e.g. how the product should be handled and protected, and recommendations for dimensioning regarding different functional requirements. To conclude, the CIB Master List is not a classification but a recommendation for presentation of properties from different aspects. The principles of the CIB Master List can be recognised in the disposition of e.g. the Swedish Building Catalogfue, which presents information about construction products (Svensk Byggtjänst 1998). ISO/TR 14177 The ISO/TR 14177 was developed as a background for the work with the international standard for construction classification ISO 12006-2 (ISO 1994). As mentioned in the introduction to this article, the Technical Report states that a classification of attributes is a necessary step towards a sound development of information systems. The following main categories of properties are suggested: Performance Material Function Price Shape Production time Location Principles for classification 8
Performance is defined as the behaviour of an object during influence by agents. Performance are functional properties. Reference to CIB Master List 1993 and ISO 6241:1984 Performance standards in building Principles for their preparation and factors to be considered are given for examples of these properties. A Function is defined as the task an object shall, or is supposed to, fulfil, e.g. transport, industry, office, trade, health care and recreation. These attributes refer to systems composed of both construction objects and users. The activities, or functions, characterise these systems. The Technical Report recommends that these attributes are used for classification of construction entities, which has also been done in ISO 12006-2 (ISO 2001) and the Swedish BSAB System (Svensk Byggtjänst 1998). Material attributes describe the integral material and molecular structure of an object. A reference is made to CIB Master List 1993 and the material properties mentioned there, e.g. weight, entity, surface structure, etc. These are Compositional properties. Finally, Other attributes like identification and conditions are mentioned. The importance of the possibility to assign status to a property is pointed out, e.g. as required, as designed and as built. These properties belong to the main class Administrative properties. The ISO/TR14177 lacks Phenomenal and Symbolising properties, which means that neither the feelings of a user in relation to a construction object, nor its meaning can be expressed or related to the material properties of the construction object. EPIC II EPIC is an acronym for Electronic Product Information Co-operation Group. The cooperation aims at establishing an international classification of construction products to be used in construction product databases (EPIC 1999). Version 2 of the standard includes both a classification of products and a classification of properties of products. The attribute structure from the CIB Master List 1993 is recognisable, but similar to this, the character of classification is weak. IFC PropertySets IFC, the Industry Foundation Classes, is an international standard for transfer of information in building product models between information systems IAI (IAI 2002). IFC is developed by the International Alliance for Interoperability, a member based global interest organisation. The standard is a developed through member-financed projects. In IFC, objects, relations and attributes are the three basic entities. Attributes are associated with objects through relations. The most generic entity for attributes is the IfcPropertySetDefinition. It has two subclasses, IfcPropertySet, which can be determined dynamically by a user of IFC, and IfcProperty, which has an explicit definition within the standard. As the user defined, dynamic parts of IFC are extended, a growing number of attributes will be defined explicitly within the standard. At present, in IFC 2.x, there are about 300 Principles for classification 9
attributes defined (IAI 2001). The explicitly defined IFC attributes which belong to the standard, have been compiled in an alphabetically ordered list in the IFC 2x Property Set Development Guide (ibid). Still, a classification to structure the attribute list is missing. The IfcPropertySets in IFC 2.x are to be seen as prototypes and not as complete property specifications. They are not complete or many enough to render a classification necessary. However, future more comprehensive specifications will need a more systematic account, among others to allow computer based information management. Example of classification of properties of construction entities This section presents an example of how the proposed property classification can be applied to properties of construction entities. The classification is not claimed to be complete or applicable in practice. The objective is to illustrate the use of the proposed classification structure. Under the main classes are examples of sub-classes and attributes. 1 Functional The subclasses below are taken from the European Construction Products Directive (Council Directive 89/106/CE 1988). Mechanical resistance and stability: deformation Safety in case of fire: fire resistance Protection with regard to hygiene, health, and the environment: susceptibility to growth of fungi Safety in use: accident protection, e.g. to exposure of electric current Protection against noise: sound insulation Energy economy and heat retention: thermal transmittance Additional functions have been added in the Swedish application (SFS 1994): Suitability for use: space layout efficiency Accessibility for disabled: wheelchair accessibility Water ressource conservation, environm. Responsible waste handling: sewage cleaning effectiveness 2 Comparative Geometry, shape: length, volume, cylindrical, spherical Position: right, left, above, below Temporal properties: completion date, construction period 3 Compositional Intrinsic properties: composition, material, mass, weight, density, elasticity Intrinsic process properties: movement, radiation, emission, bio-dgradation Production properties: prefabricated, in-situ produced Maintenance properties: clean, accessible, maintained 4 Phenomenal Objective perceptions: colour, loudness, brightness Subjective perceptions: comfort, beauty, safety Principles for classification 10
5 Symbolising Linguistic: texts Non-linguistic: signs 6 Administrative Identification: name, ID Classification: BSAB class, architectural style Description: work specification, guarantee, certificate Economical: price, taxation value Conclusions The result of this study is a proposal for classification of generic properties of systems on the basis of a well-founded theoretical framework. The classification has been applied to develop a classification of properties of construction objects. The main classes of system s properties have been related to earlier work in construction property systematic. The result confirms some earlier work but also points out shortcomings of these. For example, phenomenal properties and symbolising properties are not among the categories mentioned in earlier classifications. In this proposal all functions are collected under Functional properties. The division into Requirements, Performance and Function classes in the reviewed systems is made for reasons of presentation, and should not be regarded as a classification. Applications of the proposed classification may show that a further subdivision of the main classes probably will vary, depending on the specific kind of system s properties that are classified. For example the material properties of social organisations are much different from those of building elements. However, the main classes may provide a useful start in any property classification. A hypothesis worth testing is whether the possibility to determine the value space of an attribute depends on whether the system is known or not. For example the colour values of the NCS-system are determined on the basis of human colour discrimination, which is not relevant for all organisms. The proposed classification should be tested to structure attributes in the IfcProperty list, in CAD-libraries and in web-based product search engines. However, classification of properties gives no guidance to how product properties should be presented to different end users. This must be regarded as a separate problem area. Information must be compiled and grouped in those aspects, which interest the end user. The CIB Master List 1993 is developed as a general recommendation for presentation of product properties in documents. These principles are applied, e.g. in the Swedish Building Catalogue, and in EPIC 2. The same principles should be tested for presentation of attributes within IFC, e.g. for IfcPropertySets and for objects like IfcWall, IfcWindow etc. Principles for classification 11
References Bunge M. (1983a). Epistemology and Methodology: Exploring the World, Vol. 5 of Treatise on basic Philosophy. Dordrecht: Reidel Bunge M. (1983b). Epistemology and Methodology II: Understanding the World. Vol. 6 of Treatise on Basic Philosophy. Dordrecht: Reidel. Bunge M. (1979). Ontology II: A World of Systems, Vol. 4 of Treatise on Basic Philosophy. Dordrecht: Reidel. Bunge M. (1977). Ontology I: The Furniture of the World, Vol. 3 of Treatise on Basic Philosophy. Dordrecht: Reidel. Bunge M. (1974). Semantics II: Interpretation and truth, Vol. 2 of Treatise on Basic Philosophy. Dordrecht: Reidel. CIB (1993). CIB Master List of Headings for the Arrangement and Presentation of Information in Technical Documents for Design and Construction. CIB Report. Publication 18:1993. Council Directive 89/106/CE. (1988). European Construction Products Directive. Web-site: http//europa.eu.int/comm/enterprise/construction/internal/cpd/cpd.htm. Annex I. Engdahl S. (2001). Byggvaruinformation med IT analys av systematik och informationshantering Inst. För Byggande och Arkitektur, Lunds Tekniska Högskola. Ekholm A. and Fridquist S. (1998). A dynamic information system for design applied to the construction context. In: The Life-cycle of Construction IT. CIB/W78-98 Procedings (Bo- Christer Björk and Adina Jägbeck, eds.) pp 219-232. Stockholm: KTH. EPIC 1999. EPIC Version 2 Final Draft April 1999. Stockholm: Svensk Byggtjänst. Fors B. and Karlsson H. (1977). Kontrollistor för tekniska utredningar. Rapport I. Stockholm: Svensk Byggtjänst. Fridquist S., Hendricx A. and van Leuwen J. (2001). Towards dynamic information modelling in architectural design. In: Proceedings of the CIB W78 International Conference IT in Construction in Africa 2001 CSIR, Pretoria, South Africa. Garret H. and Hakim M. (1994). Class-centred vs. Object-centred Approaches for Modelling Engineering Design Information. Proceedings of the IKM-Internationales Kolloquium über Anwendungen der Informatik under der Mathematik in Arkitektur und Bauwesen, pp. 267-272, Weimar, Germany 1994. Hesselgren S. (1954). Arkitekturens uttryckmedel. Stockholm: Almquist och Wiksell. Principles for classification 12
Häggström L., A. Ekholm, B. Johansson, R. Lönn, H. Yngve and Cuba-Gamarra (2001). Klassifikation av Byggnadsverk och utrymmen förstudie. Svensk Byggtjänst, Stockholm. IAI (2002). IAI web-site http://iaiweb.ibl.gov. IAI (2001). IFC 2.xProperty Set Development Guide. Draft 2. Industry Alliance for Interoperability. ISO (2001). ISO 12006-2 Building construction Organisation for information about construction works-part 2: Framework for classification of information. Geneva: International Standadization Organisation. ISO (1994). Classification of information in the construction industry. ISO Technical Report ISO/TR 14177:1994(E). Geneva: International Standardization Organisation. SFS(1994) Lagen om tekniska egenskapskrav på byggnadsverk, BVL. SFS 1994:847. Svensk Byggtjänst (1998). BSAB 96 System och tillämpningar. Stockholm: Svensk Byggtjänst. Svensson K., Yngve, C. Bergenudd and E. Sandström, 2000. Processhandbok. Bilaga 1, Översikt över Fastighetssektorns rekommendationer för förvaltningsinformation. Byggstandardiseringen, Stockholm. Published in: Agger K., Christiansso P. and Howard R.. (2202 Distributing Knowledge in Building CIB W78 Conference 2002 Aarhus School of Architecture, 12 14 June 2002 Volumr 1:ISBN 87-90078-34-9, Volume 2: ISBN 87-90078-36-5. Principles for classification 13
Frederiksberg d. 28.8.2002 Lise Borup KLASSIFIKATION AF EGENSKABER? INDHOLD: 1. Sammenfatning 2. Baggrund 3. Om klassifikation og egenskaber generelt Definitioner af klassifikation Intensionale klasser og ekstensionale klasser Generisk og partitiv klassifikation - med hierarkiske relationer Klassifikation pga generiske (slægt-art) relationer Klassifikation pga partitive (helhed-del) relationer Klassifikation udfra mængdelærens klassemedlemskab - med ikke-hierarkiske relationer Begrebssystematisering i ontologier og modeller Ontologier Formale modeller Modeller og modelteori Klassifikation - modellering? Klassifikation af objekter og begreber Klassifikations funktioner A Klassifikation for begrebsfastlæggelse og -identifikation B Klassifikation for orden C Klassifikation for værdifastlæggelse Egenskaber hos egenskaber Egenskabers funktioner Egenskabskategorier Iboende egenskaber/tilstand Relationsegenskaber 4. Om egenskaber hos Aristoteles 5. Om systemer og egenskaber hos Mario Bunge 6. Om egenskaber i international standardisering 7. Om 'byggeriets' egenskaber i SB rapport 8. Om 'byggeriets' egenskaber i CIB Master List 9. Om 'byggeriets' egenskaber i 'Alfabetisk index for byggeriets produktinformation' 10. Litteraturliste 1. SAMMENFATNING 'Klassifikation af egenskaber' belyser først og fremmest egenskabers centrale funktioner for dannelse, definition og identifikation af vore begreber og for evt. ønskværdig eller nødvendig orden i vores begrebsapparat. Derfor er nytteværdien af at have styr på egenskaberne som klassifikationsgrundlag stor og oplagt. Denne må nødvendigvis baseres på, at egenskaberne i sig selv klassificeres eller opdeles i forskelige kategorier eller typer af egenskaber udfra almindelige generiske principper, idet det samlede system af egenskabskategorier udgør et hierarki med slægts-arts relationer. Systemer af BSAB02.doc 14
egenskabskategorier kan være specielle dækkende kategorierne inden for et bestemt fagområde eller disciplin, men systemer af egenskabskatagorier kan også være generelt anvendelige. Dette skyldes, at på det overordnede (eller metafysiske) plan har egenskabskategorierne sammen med substansen den ontologiske funktion at danne struktur eller ramme for alt værende eller eksisterende. 'Klassifikation af egenskaber' viser både eksempler på generelle systemer af egenskabskategorier og specielle systemer af egenskabskategorier (byggeriets). Når disse systemer sammenlignes er der lighedspunkter - så mange at de udgør et stærkt argument for, at man bruger et generelt anvendeligt system af egenskabskategorier, som i kraft af sine ontologiske funktioner kan fungere som referenceramme for specielle systemer af egenskabskategorier. Endelig har svært tilgængelige arbejder eller litteratur om klassifikation og egenskaber i begrebernes generelle betydning gjort det nødvendigt med forklaringer på andre vigtige begreber. I kapitel 3. 'Om klassifikation og egenskaber generelt' forklares således nærmere om klassifikationskoder som symbolske begrebsrepræsentationer, om intensionale og ekstensionale klasser, typer af klassifikation og anden begrebssystematisering, objekt, begreb mv. 2. BAGGRUND Uden egenskaber er der ingen begreber, idet det er egenskaberne der konstituerer eller udgør grundlaget for begreberne. Derfor er egenskaberne et centralt begreb i klassifikation. Men uanset dette forhold er generelt anvendelige arbejder eller litteratur der beskriver egenskaber og deres evt. kategorisering i arter eller typer meget sjælden - det man finder, handler i reglen om specialiserede dele af egenskabsspektret inden for en bestemt disciplin. Efter mange års praktisk arbejde med at bruge klassifikationssystemer til ordning af byggeriets informationer herunder byggeriets produktinformation, opstod på et tidspunkt erkendelsen af egenskabernes centrale betydning som klassifikationsgrundlag for disse informationer. Erkendelsen bygger på møjsommeligt indsamlet tværfagling viden om, hvad der egentlig menes med begrebet 'klassifikation', og som det gælder for egenskaberne, eksisterer der ikke mange generelt anvendelige arbejder eller litteratur, idet det der findes altid handler om klassifikation inden for en bestemt disciplin eller fagområde. 'Klassifikation i byggeriet' er ikke et dårligt udgangspunkt for indsamling og udnyttelse af viden om klassifikation og egenskaber. Et behov som har baggrund i, at byggeriet er karakteriseret ved processer, hvor resultatet hver gang er et individuelt bygværk, sammensat af en individuel komposition af komponenter, ved deltagelsen af et team af aktører sammensat til lejligheden og hvor stedet/byggepladsen hver gang er ny og ukendt. Byggeriet af de fysiske rammer for menneskets eksistens og virksomhed kan ses som et signifikant og konkret udtryk for den menneskelige skaberkraft, idet det er byggeriets aktører, der har magten til og ansvaret for at bestemme egenskaberne hos bygværket og dets komponenter. Det er klart, at disse vilkår skaber store vanskeligheder med at systematisere både byggeriets generelt anvendelige viden/informationer og byggeriets projektspecifikke viden/informationer - vanskeligheder som influerer på bl.a. byggeriets edb-anvendelse herunder anvendelsen af præfabrikeret software. Men dertil kommer, at spændvidden i omfanget af bygværker, komponenter, aktører og steder er meget stor med deraf følgende rigdom af forskellige kategorier. Når man fx kigger på byggeriets produkter viser det sig, at de optræder i 22 udaf de 30 hovedgrupper hvori UN og EU opdeler samfundets økonomiske BSAB02.doc 15
aktiviteter og deraf følgende produkter (se om SITC, CPC og NACE i litteraturlisten i kapitel 10). Det er klart, at denne mangfoldighed af kategorier inden for byggeriets overordnede emner - herunder rigdommen af produktkategorier som dels er bygværker eller komponenter i bygværker - også giver anledning til øget kompleksitet. Analyser af andre discipliners eller fagområders informationsvilkår sammenlignet med byggeriets informationsvilkår vil dokumentere byggeriets unikke situation. Men man kan selvfølgelig nøjes med at se på virkeligheden ude i byggeriets virksomheder, en virkelighed som i rigt mål dokumenterer byggeriets vanskelige informationsvilkår - der er langt imellem 'snapsene' med 'hver mand sit system' - som selvfølgelig ikke kan 'tale sammen'. Anledningen til efterfølgende gennemgang af - og kommentarer til - grundlag eller kildemateriale om 'klassifikation af egenskaber', skyldes tilsendt rapport 'Klassifikation av Byggnadsverk och Utrymmen - huvudstudie' Slutrapport 2002-06-18 fra AB Svensk Byggtjänst Svensk Byggtjänst (SB) har stolte traditioner, idet organisationen har fungeret som institutionel ramme for klassifikation i byggeriet i mere end 50 år. SB har rummet personligheder som Lasse Giertz med SfB systemet fra slutningen af 1940erne og Ingvar Karlén som skaber af grundlaget for CIB Master List i 1958. Men SB har med nye personligheder eller 'ildsjæle' fortsat arbejdet med klassifikation i byggeriet lige siden, nu senest med det tilsendte forslag til klassifikationstavler for bygværker og rum inkl. udførlige redegørelser for tavlernes teoretiske grundlag. Rapportens kapitel 4. 'Systemteoretiske grund' indeholdende afsnittet 4.1 om 'Objekt och deras egenskaper' er udarbejdet som grundlag for rapportens klassifikationsprincipper. Rapportens kapitel 9 'Klassifikation av egenskaper hos byggd miljö' indeholder i afsnittene 9.2.1 og 9.2.2 et forslag til klassifikation af egenskaberne på baggrund af redegørelsen i kapitel 4 - se gennemgang og kommentarer i nærværende kapitel 7. Gennemgangen af dette svenske arbejde, som er baseret på indhold fra Mario Bunges's (MB) 8- bindsværk 'Treatise on Basic Philosophy' udgivet 1974-1989, har resulteret i et særskilt kapitel 5 'Om systemer og egenskaber hos Mario Bunge'. Når kapitlet også indeholder en redegørelse for MB's systemkategorisering, skyldes det MB's status inden for området 'General System Theories' (GST). Hans redegørelse har nytteværdi mht belysning af de overordnede systemkategorier, hvilket er en støtte eller hjælp til at forstå slægtskabet mellem fx 'begrebssystemer' og 'klassifikationssystemer'. En anden årsag skyldes klassifikations centrale rolle i systemanalyse og systemkonstruktion, som omtalt under begrebsorden i afsnittet om klassifikations funktioner i kapitel 3. Egne arbejder om klassifikation af egenskaber er refereret i de forskellige kapitler og opregnet i litteraturlisten i kapitel 10. Kapitel 9 indeholder eget arbejde om 'byggeriets' egenskaber i 'Alfabetisk index for byggeriets produktinformation'. 3. OM KLASSIFIKATION OG EGENSKABER GENERELT Definitioner af klassifikation Klassifikation er forklaret og/eller defineret i adskillige internationale standarder. Efterfølgende er citeret fra standarder for terminologiarbejde ISO/DIS 704:1999 og ISO/DIS 1087-1:1997, for industriautomation DS/ENV 12204:1996 og for sundhedsvæsenet prenv 12264:1995 - de fleste af teksterne er oversat til dansk. BSAB02.doc 16
De forskellige standarders definitioner og forklaringer viser, at udbyttet af en klassifikation både beskrives som begrebssystemer, terminologiske systemer og klassifikationssystemer. Det fremgår også af den internationale standardisering, at ordene klassifikation og klassifikationssystem ofte bruges synonymt. Det fremgår endvidere at 'taxonomi' også er et synonym. Ud af opslag i anerkendte ordbøger fremgår yderligere almindelig brugte synonymer som 'kategorisering', 'sortering', 'gruppering' og udover 'taxonomi' nævnes også 'systematik'. Ordet 'nomenklatur' er et nær-synonym i kraft af mindre forskelle i betydningsindholdet. Definitionerne afslører endvidere, at klassifikationerne baseres på forskellige relationer eller sammenhænge (og forskellig slags logik) og deraf følgende forskellige klassebegreber eller typer af klasser samt deraf følgende typer af klassifikation. Mht de forskellige typer af klasser forklarer Mario Bunge i sin 'Dictionary of Philosophy' 'klasse' som en samling (i særdeleshed sæt) defineret ved et (simpelt eller komplekst) prædikat og opregner synonymerne: Slags, type, art/sort, dvs at klasser består af forskellige slags, typer eller arter af samlinger. (Sæt som klassebegreb har bl.a. synonymer som klasse, kategori, gruppe). Se også om 'klassers algebra' i afsnittet 'Klassifikation udfra mængdelærens klassemedlemskab - med ikkehierarkiske relationer'. Intensionale klasser og ekstensionale klasser Dette forklarer Jørgen Jørgensen nærmere i 'Indledning til logikken og metodelæren' fra 1963 (på side 92 og 93), hvor intensionale klasser forklares 'som mængder eller samlinger af emner, der har en eller flere egenskaber 'fælles'... og ekstensionale klasser forklares som samlinger eller ophobninger/mængder af emner (ting/objekter/begreber) der ikke behøver at have nogen egenskab fælles. Klassens medlemmer kan angives ved blot at pege på emnerne og sige 'dette emne er medlem' og 'dette emne er medlem' osv osv. Det er klart, at man på denne måde kun kan angive klasser med et endeligt antal medlemmer. Men antallet kan være vilkårligt stort, som det lettest ses, hvis man benævner dem med ordens- eller mængdetalordene: 'det første, det andet, det tredie etc.' Ved hjælp af talordene kan man nummerere eller tælle forskellige klassers medlemmer og derved definere deres indbyrdes størrelsesforhold' Jørgensen siger endvidere (på side 94): 'I fundamentale afsnit af af matematikken (mængdelæren og aritmetikken) indgår såvel ekstensionale som intensionale klasser, indbyrdes forbundne på højst indviklede måder. Ofte (måske altid) er de ekstensionale klasser primære i forhold til de intensionale: man begynder med at opfatte en mængde emner og finder så ved analyse af dem, at en vis del af dem ligner hinanden i en vis henseende, medens en anden del ligner hinanden i en anden henseende, en tredie del i en tredie henseende osv, således at disse dele hver for sig kan defineres som en intensional klasse. De empirisk givne ekstensionale klasser omfatter vist hver for sig altid intensionale klasser'. Generisk og partitiv klassifikation - med hierarkiske relationer Klassifikation pga generiske (slægt-art) relationer Klassifikationen er baseret på begrebernes (og de til begreberne svarende objekter) karakteristiske træk BSAB02.doc 17
eller egenskaber dvs en klassifikation udfra begrebernes/objekternes betydningsindhold. Klassifikationens sammenhænge er derfor baseret på generiske relationer også kaldet slægt-art relationer (eller type relationer) som er en type af hierarkiske relationer. Slægt-art relationen er en logisk relation vha den logiske inklusionsrelation. Bodil Nistrup Madsen forklarer endvidere i 'Terminologi - principper & metoder'på side 21 'Når man foretager en analyse af begrebers karakteristiske træk, kan det konstateres, at et givet overbegrebs træk er en ægte delmængde af dets underbegrebers træk, dvs at et underbegreb har alle overbegrebets træk og mindst et yderligere træk, som adskiller det fra andre sideordnede begreber'. På side 22 forklares 'Når man foretager en sammenligning af mængder af træk, er der tale om en sammenligning mellem to (begrebs)intensioner. Forholdet mellem over- og underbegreber kan også foretages (belyses) vha en sammenligning mellem (begrebs)ekstensioner, dvs mængden af referenter, som udpeges af (begrebs)intensionen.' Et eksempel på en alment anvendelig forklaring (dvs uden stillingtagen til om det handler om begreber, objekter, entiteter mv) findes i DS/ENV 12204:1996: 'Classification Classification is the process of arranging abstractions into a structure organised according to their distinguishing properties. Each part of the structure defines a group of things that have similar characteristics and is called a class'. Udfra Jørgen Jørgensens redegørelse for intensionale klasser vil et generisk klassifikationssystem være dannet af et hierarki af intensionale klasser. Klassifikation pga partitive (helhed-del) relationer Klassifikationen er baseret på begrebernes/objekternes sammenhænge eller sammenkædning, hvor et af begreberne svarer til et objekt som en helhed og det andet begreb til en del af denne helhed. Klassifikationens sammenhænge er derfor baseret på partitive relationer også kaldet helhed-del relationer. ISO 1087-1 definerer 'partitiv relation': Hierarkisk relation mellem to begreber hvor et af begreberne svarer til et objekt som en helhed og det andet begreb til en del af denne helhed. Helhed-del relationer er en type logiske relationer som Mario Bunge (MB) i sin 'Dictionary of Philosophy' refererer til og forklarer ud fra 'semigroup theory' eller delgruppeteori - en af de simpleste af alle teorier og en af de mest nyttige i eksakt filosofi. En delgruppe kan defineres som et tilfældigt eller vilkårligt sæt S sammen med en associativ operation Ε (dvs sammenkædning) mellem hvilke som helst to medlemmer af S... Mario Bunges udredninger bringes i forbindelse med hans omfattende forklaringer af begrebet 'modelteori'. MB forklarer endvidere under 'Part/Whole', at der er tale om en central ontologisk relation, som bør være skarpt adskilt fra de matematiske begreber for 'set membership and inclusion', hvor 'set' betyder 'en samling af items med fastlagt medlemsskab'. Hans definition af 'part/whole' er: Hvis x og y er ting, så er x en del af y, hvis x som en fysisk tilføjelse til y = y. Dvs, hvis x er et hjul og y er en bil, så er x (hjulet) en del af y (bilen), hvis x (hjulet) som en fysisk tilføjelse til y (bilen) = y (bilen). ISO/DIS 704:1999 forklarer bl.a. om 'partitive relationer': En partitiv relation kan siges at eksistere, når det overordnede begreb repræsenterer en helhed, medens det underordnede begreb repræsenterer BSAB02.doc 18
dele af denne helhed. Delene kommer sammen (sammenkædes) for at forme en helhed (nogle helheder udgør en komposition som en sammenbygget konstruktion eller som en sammenblanding/mix).... Partitive relationer kan også udtrykkes som lodrette og horisontale serier. De dele som danner helheden må være ensartede af natur (fx atomet i en iltmolekyle) eller tydeligt forskellige fra hinanden. En eller flere dele kan være obligatoriske (fx essentielle) eller valgfri (fx ikke-essentielle). Nogle dele er ikke essentielle men begrænsende ved at de tillader helheden at være adskilt fra andre ensartede sammenfattende begreber. Nogle dele kan være mangfoldige (fx begrebet 'side' som del af en bog) eller variable inden for en række/omfang/udvalg/sortiment/klasse (fx en pen har som del enten en blækbeholder, en blækpatronhylster eller en blækrefill). For at identificere de essentielle egenskaber hos et partitivt begreb, er det nødvendigt at fastlægge udstrækningen af det sammenfattende begreb først.' Udfra Jørgen Jørgensens redegørelse for ekstensionale klasser vil et klassifikationssystem baseret på helhed-del relationer være dannet af et hierarki af ekstensionale klasser. Klassifikation udfra mængdelærens klassemedlemskab - med ikke-hierarkiske relationer Klassifikationen er baseret på 'klassers algebra' dvs den matematiske operationslære baseret på forenings- og kombinationsoperationer. 'Klassers algebra' forklarer Mario Bunge som den gren af logikken, som behandler sæt som helheder og undersøger deres 'union', 'intersection' og 'komplement' dvs deres forening, deling og udfyldning. På engelsk tales der om 'set theory' - på dansk kaldes det mængdelæren. Som forklaret ovenstående, er de simple partitive relationer baseret på en sammenkædning af helhed-dele noget helt andet - MB forklarer om 'Part/Whole', at der er tale om en central ontologisk relation, som bør være skarpt adskilt fra de matematiske begreber for 'set membership and inclusion', hvor 'set' betyder 'en samling af items med fastlagt medlemsskab'. Mario Bunges øvrige redegørelser for 'set' og 'set theory' i hans 'Dictionary of Philosophy' bekræfter den gamle tekst hos Jørgen Jørgensen som anført i afsnittet om intensionale klasser og ekstensionale klasser at 'I fundamentale afsnit af af matematikken (mængdelæren og aritmetikken) indgår såvel ekstensionale som intensionale klasser, indbyrdes forbundne på højst indviklede måder.' Et eksempel på en klassifikation udfra mængdelærens klassemedlemskab og deraf følgende ikkehierarkiske relationer finder man i Bjørn Bindslevs CBC system med tilhørende klassifikationskoder. I CBC systemet bliver byggeprocessens objekter eller begreber henført til eller klassificeret og kodet udfra deres relationer til systemets 'universalklasser', 'komplementærklasser', 'foreningsklasser' og 'fællesklasser' (der findes i øvrigt også en nul-klasse dvs en klasse uden medlemmer men den er vist ikke med i CBC systemet). Traditionel klassifikation udfra objekternes/begrebernes generiske relationer i kraft af deres betydningsindhold er ikke inkluderet i systemet, idet de enkelte overordnede klasser er underopdelt i ekstensionale klasser i en kombination af klasser med hierarkiske partitive relationer og klasser med de ikke-hierarkiske relationer som optræder i mængdelæren. Det specifikke betydningsindhold af systemets objekter/begreber er afdækket ved en identifikation af de konkrete eller projektspecifikke objekter/begreber - en identifikation foretaget ved hjælp af løbenumre ifølge en såkaldt primærnøgle. BSAB02.doc 19
Som grundlag for CBC systemet citerer Bjørn Bindslev forskellige udsagn fra bl.a. Susanne K. Langers (SL) 'An Introduction to Symbolic Logic' 2. udgave 1953. Her fastslår SL på side 117 at 'A class is the extension of a concept, whatever that extension may comprise'. SL forklarer senere på side 130, at 'The meaning of a concept is called its intension... If we speak of a class merely naming its class-concept, we are considering the class 'in intension'... Since we are never to name certain individuals any more, the capital Roman alphabet is released from its original service and may be put to the new use og naming certain classes.' Dvs en klassifikation der er helt frigjort for virkelighedens egenarter bestemt af egenskaberne hos de konkrete eller projektspecifikke objekter/begreber dvs deres betydningsindhold. Klassifikationen er derimod baseret på bestemte ekstensionelle klasser med klassemedlemmer, som anskues udfra deres rolle i 'universalklasserne', fællesklasserne', 'foreningsklasserne' og 'komplementærklasserne' - eller ifølge MB som matematiske begreber for 'set membership and inclusion'. Begrebssystematisering i ontologier og modeller Ontologier I 'Dictionary of Philosophy' definerer Mario Bunge ontologier som teorier. De handler om metafysiske forhold, dvs om de mest almene træk hos virkeligheden som fx reel eksistens, forandring, tid, tilfælde, tankegang og liv. Ontologier kan opdeles i generelle og specielle (regionale) ontologier, hvor generelle ontologier studerer begreberne for rum, tid og begivenheder... MB forklarer endvidere, at hvad enten ontologier er generelle eller specielle kan de 'dyrkes' enten spekulativt eller videnskabeligt. Endelig fastslår MB, at ontologier i kraft af deres funktioner som teorier ikke er klasser. I 'Ontologies for Knowledge Sharing' forklarer Sowa om ontologier: - logik er ren form, og ontologi sørger for indholdet - uden ontologi, siger logik intet om ingenting - uden logik, kan ontologi kun defineres og diskuteres i uklare almindeligheder - Aristoteles skabte grundlagene for begge Efterfølgende forklares om, at ontologiske teorier kan bruges i formale modeller til at beskrive en slags generel virksomhedsmodel samt mere overordnede forklaringer på begreberne 'formale modeller' og 'modeller og modelteori'. Formale modeller I 'GERAM: Generalised enterprise architecture and methodology af 1997-10-20 (ISO/TC 184 Industrial Automation Systems and Integration N 500 Annexes A 1) forklares ontological theories: Ontologiske teorier er formale modeller af begreberne som er brugt i virksomhedsrepræsentationer... Ontologiske teorier beskriver en slags generel virksomhedsmodel, diskuterende de mest generelle aspekter af virksomhedsrelaterede begreber (funktion, struktur, dynamik, omkostninger osv), og definerer betydningsindholdet af det anvendte modelleringssprog. I prenv 12264:1995 forklares 'formal models': 'An emerging kind of concepts-representation system is the formal model. It shall provide a set of symbols (usually lexical marks on paper or their equivalent in a computer system) and a set of formal rules to manipulate them. They are intended to be interpreted BSAB02.doc 20