Understanding the order of engineering design research

Engineering design research manifests as a platfonnfor exploration, desription, alTange?nent, rationalization, and application of fusign hnowledge. Whal we can see when we are looking at the research into enghrcering design is an alrnost chaotically fragnmted pfuture. Is it possible to haae a holistic view on the conlents and internal relalionships of engineering design research? This paper cons'iders teleology, a refleclion of a branch of philosophicaL speculations, as the dochine of ordering hnowledge of engineering fusign and structuring engineering design research according\. Teleologl exphins tlmt the uhhnate reason behind design is lo sustain human exislence and,well bemg fi airtual creation of artifucx and sentices for society. To this end, knoutledge of engineering research is supposed to be transferred fron the platfonn of scientific/theoretical exploration and conprelunsion to the platfonn of technical/pragnatic application. This implics 'a natural streaming of knowledge of engineering design. In order to tnahe the teleological explanation operational, a framework of reasoning has been constructed hy adopting the analogt of the source, clmnnel and sink of a stream. To represmt the source, channel and sink categaries of engineedng design knouLedge, lhe author inaugurated nine categories in the f ameworh. It has been hypothesized that the intt'oduced categoties are equally aalid for research in engineedng dtsign as well as for the knowledge of mgineering design. Within each category, research domains and trajectories haae been delined. The proposed, teleology-based fntrnework lends itself to a better undcrstanding of the disciplinary articulation and intrinsic relationships of engineering ilesign research. It is hoped, arnong olher things, to fonn a basis for a shared und,erstanding, to make the influence of decisions on research prograrns more lransparenl, as welL as lo facilitate organizing subject materials for uarious rfusign courses. Keyuonls: engineefing design research,, leleologl of engineeilng design, natural slreant of knowledge, research categoties, research' d ornains, re search trni e ctories.


I Introduction and development of a framework of reasoning
Engineering design is a creative act, which is understood to be a partially scientific discipline [42]. Design science intends to explore design-related knowledge, look for an understanding of design, search for all forms of truth, and ultimately, explain the act of designing by humans.
Eventually, engineering design research is the instrument for exploration, description, arrangement, rationalization, and application of design knorvledge. The aim of this paper is to conclude about the contextual arrangement and intrinsic relationships of engineering design rcsearch, if these exist at all. The motivation behind thiswork comes from the observation that engineering design research shows a rather chaotic picture no matter if we look at it from a distance or from inside. On the contrary the analytical rationality of science, which is especially dominant in natural and abstract sciences, exprcsses a strong attempt to categorize and arrange all pieces of the explored knowledge [45]. The 'scientific method' attempts to introduce order by stt'ucturing the elements of knowledge so as to make proper actions, judgments and evaluations possible. But, can we otder engineering design knowledge if the researth that produces this knowledge does apparently not obey to order or rule? Or; can we understand engineering design research without a proPer comprehension of knowledge of engineering design? These have been the main issues for the research whose recent results are being reported in this paper.
The first assumption of the author has been that engineering design research does obey an order and it can be comprehended by taking the nomothetic relationships of design knowledge into consideration, Nomothetic relation-ships are abstract, general or even universal statemenls or larvs. After Bohm, D., two alternative views can be formed, explicate and implicate t5]. An explicate view is related to obserrrations and allorvs creating order by phenomenology. Implicate view relates to comprehension and allows creating order by cogitation. In the end, an implicate view creates a holistic order that mutually enfolds all relationships of design knowledge. Adopting an implicate vierv can definitely help us to discover some nomothetic relationships, but it necessitates an adequate doctrine that enables us to explore any ProPer relationship. The question is what kind of doctrine can be adopted to obtain any deeper understanding ofthe content and relationships of design knowledge in an implicate way?
In our case, unfortunately, the strategy of inductive reasoning to reach fiom the facts observed in real life and literature to a hypothesis or a model of reasoning does not work. We have to appeal to a nlor€ speculative doctrine, which lends itself to the requested implicate vierv.
It has been hypothesized that the doctrine of teleology, rather than of mechanism, must be followed toward a better comprehension of the order of engineering design knowledge and reseatrh. As a philosophical category teleology provides explanations of phenomena by the Purpose they sewe. The doctrine of teleology teaches us about the final r€asons of engir-reering design, and reveals the purpose of the knowledge of engineering design It points at the fact that engineering design is being directed towards an ultimate purpose that manifests in virtual creation of artifacts and services for society [I2]. That is, as opposed to mechanism, the teleological view indeed claims that engineering design is determined not only by mechanical causes, but also by an over-all purpose. The doctrine of teleology also attempts to account for the features ofengineering design knowledge by appealing to their contribution to functioning and attain-t7 Fig. l: Conceptual framework ofthe order in engineering design research ments of goals. Teleology also says that the ultimate reason does exist without our awareness, recognition or understanding. Neglecting all other implications, we can claim that rhis ultimate reason is to sustain human existence, to which engineering design contributes through its purpose. Actually, the contribution of engineering design to the fulfillment of soc! etal needs for products and services explains its occurrence and the way ofoccurrence.
The third assumption has been that, on the one hand, the purpose of engineering design derermines the order and the intrinsic relationships of engineering design knowledge. On the other hand, projecting the order of engineering design knowledge to the research of engineering design provides us with the requested implicate view. The hypothesis, supported by some fundamental observarions, is that the global discipline of engineering design is naturally rationalized and directed. The knowledge is transferred from the scientific (or theoretical) exploration and comprehension to the technical (or pragmatic) application. Hence, the underpinning idea behind an implicate view can be this narural flow of knowledge through design. The basis of demarcation of the fields of t8 knowledge, as well as in the attentions of research, is the context of purpose. With regards to engineering design research, the categories offields ofinterests can be detailed for contents at various levels. Based on these postulates, a framework of reasoning has been constnrcted that serves four functions: (a) identification of the contexrual categories of engineering design research, (b) disintegrarion of the categories ro research domains and making the interactions and dependencies explicit, (c) decomposition of the domains to research trajectories, and (d) breaking down the trajectories to research approaches, whenever this is possible or needed. A research category is a philosophical concept that is based on our thoughts and organizes our experiences accordingly. A Eesearch domain is a disciplinary branch of engineering design knowledge and research, represenring a parricular field of competence or expertise such as history ergonomics, and management. A research trajectory indicates a stream of operations sharing the same objectives and concepts, which involve modeling a typical example. Finally, a research approach concerns the concrete treatment of specific research issues in engineering design research.
In order to be able to cast the natural flow ofknowledge into a framework of reasoning, the analogy of the source, channel and sink ofa stream has been used to define the contextual categories (Fig. l). As specific to engineering design knowledge, the author inaugurated nine research categories in the framework. The source categorie,s of engineering design knorvledge and research are the categories that endow with the fundamental mental capacity for engineering design. From an epistemic point of vieq knowledge pertaining to design may belong to one of four contextual categories: (a) knowledge of human assets, which must be an all-preceding source category (b) generic knowledge of design, which represents a part of universal knowledge, plus (c) artifact knowledge and (d) Process knowledge, which complement each other. The clrunneL categories provide knowledge for establishing couplings betrveen ttre scientific/theoretical knowledge and pragmatidtechnical knowledge categories.
The purpose of design philosophy is to improve understanding, of design theory is the proper reasoning with knou'ledge, of design methodology is the proper utilization of knowledge, and of design technology is the effective application of knowledge. The sin k category is concerned with generation of knowledge that is necessary for the ultinlate deployment of the whole engineering design knorvledge. Design application alone represents this category. l)ue to space limitations, the discussion of the proposed structure of engineering design knowledge and resean:h tnust be restricted to the level of design trajectories, as the lowest. 2 Research trajectories in human assets We regard human assets as the whole of the mental and physical capabilities as well as potentials that are owned by a community of human beings and that a business needs to enable its processes to generate new values' Humans relate to engineering design in three forms. They can be (a) scholarly originators of general and specific design knowledge (design philosophers, design scientists, design theoreticians, designers), (b) design problem solvers (design methodo-Iogists, engineering designers, product and design system developers), and (c) profiteers from the design deliver-ables (users, consumers, undertakers, students)' Within the research category of human assets' six research domains can be identified that decompose to various research trajectories.
They are shorvn in fig.2. Design psychoLogy studies the mind and behavior of designers as well as of the people who are affected by design in whichever lbrm [53]. Individual designers, collaborating designers and designer-user mixed grouPs have been considered l4). Duign cognition research investigates the act or process of knowing, the cognitive mechanisms and mental concepts of knowing, perceiving and conceiving design knowledge, intuitions and hypotheses [49]. It disregards horvever feelings, emotion, beliefs and volition. It also focuses on the cognitive processes (logical, visual, spatial, and functional thinking) and models of designing [9] and the various techniques of elicit.ing design knowledge from the design activity on decision, product, and project levels [35].
Stimulated by globalization of industrial production and the need for customized products rvorldwide, researchinto de' sign ethnograpliy focuses on distillation of culturally relevant design knowledge, as well as on culture-sensitive design of artifacts [7]. Design aesthetics, the science of sensuous knowledge, studies various aspects of experience beyond the superficial appearance of products, the impression and appreciation of beauty in products, emotional reactions of humans, and the creation of aesthetic values [55]. Design aesthetics involves the study of perception of shape, functions, attributes, and behaviors. It stresses a theoretical argumentation about form, color and other sensory Properties. In the domain of de' sigtt ergononilcs, the major research issue is accumulation of knorvledge for optimizing the connection between clusters of humans and products/environments [3]. While physical ergonomics concentrates on the investigation of physical human-product interaction with an emphasis on the increase of effrciengv, safety, comfort and convenience, informational ergonomics pursues very analogous objectives in mental human-product interaction [37]. High-fidelity multi-aspect modeling of humans based on anthropometrical data, material properties and physical functions, in particular for the investigation of human-product interactions in various user environments, is another main trajectory of research in this domain. Supported by the general theories of marketing' product nnrketing research covers a subset of fields of interests that specifically belong to marketing of artifacts and to related human assets The structure ofresearch in the contextual category ofdesign knowledge is shown in Fig. 3. By adopting the doctrine of epistemology of scientific knowledge, dcstgn epistemotogy deals with the competing theories of design knowiedge wiih respect to its origins, nature, forms, constituents, structure as well as to its validation and merhods tl3l. There is a srong coupling to the category of human assets, since human involvement is the only rvay of acquiring design knowiedge from the natural, social and technical sciences, as well as from design practice. Although it was found to be fundamentally empirical in nature, engineering design research has made design knowledge more theoretical by structural reasoning, abstraction and generalizarion, and logical processing t261. Contemporary research in this domain has found that, in the most general sense, design knowledge can be synthetic, as acquired by the cognitive senses, and analytic, as derived by mental reasoning. Design intelligence extends the intrinsic forms of human intelligence, rhar is, linguistic, musical, logical, spatial, kinaesthetic and personal thought processes Il l.
The research in the domain of dzstgn intelligence investigates the principles and forms of c<lmmon, plausible and non-deterministic design reasoning and learning, togerher with the apprehension of specific problem solving capabili-ties, the nature and manifestations of design creativity, as well as the nature of design problems and handling of hoiism and complexity of design problems [8]. While design thinking investigates the cognitive and intuitive mechanilms, design reasoning considers the rational foundations with the aim of deriving principles for procedural inference [31]. Design reasoning based on formal logic has been considered u *.u-rl, of mechanical realization of design, rather than a means of achieving a creative leap [36]. In the domain of dzsign exter_ rnlizntion, research splits into three main trajectories: la) gen_ erating mental images (concepts) and converting them to abstract or concrere schemata, (b) reprcsentationi applicable to transfer mental images to external representations, and (c) communicarion of design ideas, information and design knowledge [50]. The research in the domain of fusisn education decomposes ro the srudy of (a) design teaching aid learning processes, methods and tools, (b) ctevelopmeni and experiencing with various design learning pro$?ms, and (c) exercising product design and realizarion by co-located or dis_ located coilaborative groups [46]. One of the most important findings of research in the design instruction trajectory is the observation that design is not separative, like science, but integrative, like art and engineering, which has to be characteristic for education in the information age [40]. 4 Research trajectories in knowledge of artifacts Ihowledge related to artifacts, also named technical systems or products, representi a specific subset of design knowledge. In the context of design, a wealth of complix artifacts appeared during the great industrial revolution and later. Historically the first artifact theories were about mecha- The author distinguishes three domains of research into the rtalm of artifacts, specifically the domain of technical systems, product principles and ardfact rnanifestations (Fig.4). Researrch recognizes technical s)stems as goal-implied, synergetic arrangements of organs, and places the emphasis on the laws of transformations, casual changes and optimization of operation [25]. processes, and devising theorems, rules and procedures as a set of instructions for solving design problems. Process modeling studies the theoretical formalization of processes, the ways of contextual understanding and information technological modeling of processes [30]. Understanding design processes is the topic for ptocess theory specializing in design [51]. The creative design processes have been found dependent on the subconscious ideas that produce something not known beforehand [21]. Monitoring and protocol study are applied to understand the human ways of designing, processing design information, applying knowledge, collaboration, use of tools and methods, and design communication.
The research domain of arxtfucttnl processes spreads over existential, operation, application and service processes of products. 'Ihese are essentially the constituents of the life cycle ofproducts. The research studies these product-related processes in a holistic rvay, with the aim of understanding, modeling, simulating and optimization. Implicate processes re' late to the realization and exploitation of'products. Research in this domain deals with technological, production, sales and reclaiming processes. Technological processes are about manufacturing and assembling parts, and they are studied in order to provide information for designers for technology-oriented decisions in the process of designing artifacts.
Production processes are about the realization ofproducts in Historically, philosophical inquiry targered rhe issues of epistemology, aesthetics and ethics of lngineering tl4l. Design philosophy is the highest level speculatiue ttri"ling about (a) the existence and manifestation of design, $J the role and position of design in society, (c) the hiitorical evolution of design, and (d) rhe fioundational basis of design thinking [61]. Philosophy of design is sometimes equated*to a mek-theoretical fiamework for design theories gS+1. fne author considers design science, design history design policy, design ethics and design axiology as current domains of design philosophy research, as shown in Fig. 6. Design sc,ience is a scientific study ofdesign activity in its context, urrd g.rre._ ates a collection of logically arranged knowledge in rhe realm of design. (In conrrast, the science of design is the study of a scientific way of designing). Hubka, V and Ede4 W. E. identified two constituents of design science as conceprs of technical information and of design methodology [24]. Willem The research in the category of design theory decomposes ro the domains. of design theories, design semantics, and design systematization (Fig. 7). Research in rhe domain of design thio_ ries. deals with both global and local theories. Descriptive, pre_ scriptive and formal theories have been identified ftS1. Global theories concer-n both design artifacts and design processes [20]. Hubka, V and Ede4 W. E. specified the content for the theory of technical systems as the total of sub-theories such as property theory it.,r.t,r." theory, transformation (process) theory conformational theory life-stage ,1r.9.y, evolurion theory and ecology theory [241. a globil design problem solving theory generally serves as a scientific basis for rationalizing multidisciplinary product development. One of the proposed global theories is general design theory (GDT), which aims ar introducing an idealized modil for the evolutionary design process [60]. Specific design theories are localized in scope, that is, they ar..onrr..t"d to o.r.
or several particular problems of engineering design. A local design theory emerges when there is a testable explanation of why the method behaves as it does. Formal local theories are typically based on formalized theorems, rules and structured procedures, and are used in automating solution finding for design subproblems [6]. Research  Based on the work of Russel, B., we can conclude that there are no truths par excellence in engineering design, which makes its axiomatic definition logically unsupported [48]. The domain of dzsign systemtttizntion incorporates research into (a) design decision-making, (b) design instrumentation, (c) design optimization, and (d) design automation. The research studies individual, team and organizational levels of design decision-making. Design instrutnentation studies the dialect of design tools and design processes, humans and tools, and problems and tools. Design oPtimization research targets both qualitative and quantitative methods of system, structure, shape and parameter optimization. Design automation research, which assumes that engineering design is a computable function, studies computer-based problem solving strategies, methods, heuristics, creativity, Iearning, and reasoning. Its ultimate aim is formal design inference, automated problem solving, and transplantation of design capabilities. 8 Research trajectories in design methodology Design methodology is the theory of design methods, activities and techniques. Many researchers have proposed a separation between the so-called scientific method and design method [0]. This view is well supported by the vast amount of non-scientific knowledge that is applied in engineering design. The author's understanding is that the category of dcsign methodology research embraces the domains of design methodologies, design innovation, design modeling and modeling methods (Fig. 8). Design methodologies involve the systematic analysis and organization of the rational, experimental and heuristic principles and processes in order to solve design problems. Eekels, J. and Roozenburg, N. F. introduced the notion of design methodics to differentiate the theory of methods from the development and application of methods. Design methods do not attemPt to say what design is, or how human designers do what they do, but rather provide tools by which designers can explain and perhaps even replicate certain aspects of design behaviors [27].
Desigz innoaation research creates a scientific basis for rationalizing multidisciplinary product development and fa-cilitates solution finding for design problems. Also studied are the relationships benveen design innovation strategies and the underlying range of technical choice available to the design team [33]. With the advent of digital computers, a new field of attention has gradually been emerging in design methodology, dcsigt. rnodeLing. Its objective is to generate mental, cognitive, formal and symbolic models of humans, artifacts, processes and knowledCe [2]. It investigates the role of modeis in externalization, communication and testing of design ideas [62]. Design modeling covers the research trajectories of requirement engineering, functional, structural, mor-phological, physical, and behavioral modeling of products. Expectations coming from the phases of the life cycle of products ale also investigated. The research domain of mod,eling nrcthock deals rvith mathematical, verbal-textual, symbolic, visio-spatial, virtual and material methods of representation of humans, artifacts, processes and knowledge, and their integral use in engineering design. Typically, verbal starting points are transformed into initial physical representations supported b1' visuo-spatial thinking [38]. 9 Research trajectories in design technology Science philosopher Ziman,J. said that science in application is technology [63]. Cross, N. asserted that design is more a technological activity than a scientific activity; therefore it has to be seen from the more practical and stable technological model of human action, rather than from a formal scientific theory [0]. According to the authol design technology' is the most characteristic channel category that converts the general knowledge of engineering design to explicit prcduct models and representations. With the advent of digital computers, design technology has become one of the most intensively studied research categories of engineerin$ design. Therefore, sorne 30 years ago, design technology rcsearch showed an unexpectedly rapid progress [23]. The involvement of computers in design, pulled by the needs of industry and pushed by the rapidly evolving computer technology, has actually brought about the concept ofdesign technology. The n..ro fundamental problems have been the processing of design knowledge by computers, and the development of design supporting systems. The specific research domains are shown in Fig. 9. Research in the domain of fusigninformath.s aims at studying all non-specific aspects of handling data, information and knowledge related to humans, methods, tools and products.
It concerns acquisition, representation, structuring, processing and validation. The premier issue has been processing visual and spatial information, which is enabled by the methods and techniques offered by computer graphics research and image pnccessing [6]. Research in the domain of design languages ta{gets formal product definition languages as well as product description languages of neutral formats. Another research domain, fusign mind,ware, deals with the issues of structuring and archiving design data, information and knowledge in design databases in textual, numeric, visual and multi-media forms. Knowledge bases for design relying on conventional representation schemes, taxonomical ontologies, or multimedia represenrarion as well as knowledge asset warehousing are also investigated [41]. The research domain of dcsign sortware comprises research into the exploration of theories, methods and algorithms for (a) design utilities, (b) graphics-based modeling sofrware, (c) analysis software and (d) simulation sofnvare [32]. research has a broader and a narrower interpretation, and is still a matter of debate [29]. In its broader interpreration ir One trajectory of research creates norms and measures of design quality, and the other is involved in the deployment of quality [52].
Design sta,ndardization research targets the increase of efliciency and quality of design by investigating the principles of standardization, stating the requirements and characteristics ofartifacts, processes and methods, and generatingcodes and norms with a pronounced relationship to design technology [54]. Receiving  11 Conceived Influences of the framework of reasoning Driven by practical or utilitarian considerations, one can obviously ask: What benefit can we draw from all these? For design scientists, researchers and educators it is most probably not diflicult to see the relevance or usefulness of this (or other purposeful) reasoning model, but they might meditate about the best forms of utilization. Most probabll', designers and design managers will formulale their question even more profanely: Can we design better now? All these questions in the context of utility are justified. Each theory must be measured in terms of its usefulness. Implicitly, this is the message of the reasoning model itself. Howeveq more often than not, the usefulness of a theory or a framework of reasoning appears indirectly, rather than directly. And the indirect influence might be much greater than any direct influence. understood by analogy with image generation in TV sets.
The transmitted electronic signals should be in an arrangement and form that result in the correct screen picture. The contribution of the proposed reasoning model to the understanding of engineering design knowledge is of this kind.
A-lthough further research is needed, the conceptual framework can be used to arrange the disciplinary knowledge of engineering design and to facilitate, among other things, knorvledge asset management, ontology development, and education material development.
In the course of time, some specific topics and approaches of engineering design research incidentally receive greater emphasis at the expense of other issues. Everywhere in the rvorld, design research grants are awarded mainly by particular local interests, very rarely with concern about the development of the science of designing as a whole. Granters control the publication possibilities depending on their commercial objectives. The orientation of scientific development is influenced more by the editors-in-chiefs of publishing houses than by an unprejudiced understanding of useful trends and a comprehensive vierv on the ori€ntation of scientific developrnent. The conceptual framework gives a kind of topography of engineering design research, rvhich can be utilized in the strategic and tactical hnancing and organization of engineering design research. The integral view that it provides on engineering design research can make the articulation ofresearrh on the level oftrajectories and approaches transpar€nt for the decision makers, and indicates the emergence of a new paradigm when harmony with the framework tends to cease and adaptation becomes a necessity.
Understanding the order, exploration mechanisms and knowledge transfer of engineering design research has become indispensable in an age when technological progress is accelerating almost unconstrained. The teleological reasoning model says that the scientific (or theoretical) knowledge explored by research in engineering design must be transferred to technical (or pragmatic) application. Shortening the time of knowledge transfer fiom research to Practice and coping with the knowledge explosion are generally recognized issues. The author believes that a better understanding of the relationships between the knowledge produced by the various branches of research enables us to better cope with the pragmatic issues. What is waiting for further research is the study of those mechanisms that facilitate the achievement of knowledge intensiveness in product development based on a short-term conversion of the results of engineering design research.