Designing as Interpretation

The paper suggests an interpretative approach to the empirical study of design processes. Design processes are conceived as social processes of interpretation and construction of meaning, and potentially of context generation. In contrast to models which conceive designing as a goal-directed process, an interpretative approach suggests a methodological reorientation. It assumes that design goals are more or less incomplete and vague at the beginning of a design process and are interpreted in contexts and in part are created by designers in the design process on the basis of their experience, embodied skills, and practices. The interpretative paradigm in design research seeks to observe, investigate, and describe practices that designers use in the process. Rather than attempting to determine and prescribe how practitioners ought to do their work, the research question is on how work is actually done - how interpretation is achieved by designers in particular design processes. An extract is analysed in some detail in the paper. These data are taken from the transcript of a case study of a design process in practice. Sociological and socio-linguistic (‘sensitizing’) concepts such as frames and contexts are adopted to describe and analyze some practices observed in the episodes. The paper focuses on an aspect of designing – various forms of involvement and stances designers’ take on in the meaning making process of interpretative design work. Interpretative analysis takes into account designers’ alignments which constitute “participation frameworks” and ground designers’ multimodal practices in different media (language, drawing, gesture). Goffman’s (1981) concept of “footing” is used to reveal more subtle shifts in stances that designers take in designing. Investigation of referential practices designers use in some utterances in the observed design conversation suggests that designers step into, displace, and position themselves in transformed, “keyed” situations to experience the solicitations of design situations more directly and to take the role of others as well as the role of objects. These practices appear to be part of designers’ ability to construct meaning by establishing perspectives and getting “maximal grip” on design situations so as to exert their skills. Analysis of types of stances designers take in an observed design process, some of which addressed in the paper, may provide a way to describe an aspect of designers’ artistry and to characterize the particularities of unique design processes. The suggested approach is intended to contribute to a better theoretical understanding of designing and to the methodology of design research as an ‘epistemology of practice’. Interpretative analysis also aims to provide description of designers’ practices which may, as its practical benefits, contribute to ‘the reflective turn’ in design research. Keywords: Design Research Methodology; Design Practices; Framing; Case Study</p

Optimal path and cycle decompositions of dense quasirandom graphs

Motivated by longstanding conjectures regarding decompositions of graphs into paths and cycles, we prove the following optimal decomposition results for random graphs. Let $0<p<1$ be constant and let $G\sim G_{n,p}$. Let $odd(G)$ be the number of odd degree vertices in $G$. Then a.a.s. the following hold: (i) $G$ can be decomposed into $\lfloor\Delta(G)/2\rfloor$ cycles and a matching of size $odd(G)/2$. (ii) $G$ can be decomposed into $\max\{odd(G)/2,\lceil\Delta(G)/2\rceil\}$ paths. (iii) $G$ can be decomposed into $\lceil\Delta(G)/2\rceil$ linear forests. Each of these bounds is best possible. We actually derive (i)--(iii) from `quasirandom' versions of our results. In that context, we also determine the edge chromatic number of a given dense quasirandom graph of even order. For all these results, our main tool is a result on Hamilton decompositions of robust expanders by K\"uhn and Osthus.Comment: Some typos from the first version have been correcte

Purchasing Organization and Design: A Literature Review

This paper presents the results of a comprehensive literature review of the organization of purchasing covering the period from 1967 to 2009. The review provides a structured overview of prior research topics and findings and identifies gaps in the existing literature that may be addressed in future research. The intention of the review is to a) synthesize prior research, b) provide researchers with a structural framework on which future research on the organization of purchasing may be oriented, and c) suggest promising areas for future research.purchasing, supply, procurement, organization, institutional structure, structure, institution, design, performance, literature review

The existence of designs via iterative absorption: hypergraph FF-designs for arbitrary FF

We solve the existence problem for $F$-designs for arbitrary $r$-uniform hypergraphs~$F$. This implies that given any $r$-uniform hypergraph~$F$, the trivially necessary divisibility conditions are sufficient to guarantee a decomposition of any sufficiently large complete $r$-uniform hypergraph into edge-disjoint copies of~$F$, which answers a question asked e.g.~by Keevash. The graph case $r=2$ was proved by Wilson in 1975 and forms one of the cornerstones of design theory. The case when~$F$ is complete corresponds to the existence of block designs, a problem going back to the 19th century, which was recently settled by Keevash. In particular, our argument provides a new proof of the existence of block designs, based on iterative absorption (which employs purely probabilistic and combinatorial methods). Our main result concerns decompositions of hypergraphs whose clique distribution fulfills certain regularity constraints. Our argument allows us to employ a `regularity boosting' process which frequently enables us to satisfy these constraints even if the clique distribution of the original hypergraph does not satisfy them. This enables us to go significantly beyond the setting of quasirandom hypergraphs considered by Keevash. In particular, we obtain a resilience version and a decomposition result for hypergraphs of large minimum degree.Comment: This version combines the two manuscripts `The existence of designs via iterative absorption' (arXiv:1611.06827v1) and the subsequent `Hypergraph F-designs for arbitrary F' (arXiv:1706.01800) into a single paper, which will appear in the Memoirs of the AM

Euler tours in hypergraphs

We show that a quasirandom $k$-uniform hypergraph $G$ has a tight Euler tour subject to the necessary condition that $k$ divides all vertex degrees. The case when $G$ is complete confirms a conjecture of Chung, Diaconis and Graham from 1989 on the existence of universal cycles for the $k$-subsets of an $n$-set.Comment: version accepted for publication in Combinatoric

Analysis of HOM interaction between cavities by multi-modal s-parameter measurements

Accelerating cavities exchange HOM power through interconnecting beam pipes in case of signal frequencies above the cut-off of their propagating waveguide modes. This may lead either to improved HOM damping or - in the case most severe - to unwanted phase coherence of fields to the beam. Therefore the knowledge of the scattering properties of a cavity as a line element is needed to analyse all kinds of RF cavity-cavity interaction. Since there is a lack of measurement tools capable to provide a multidimensional scattering matrix at a given frequency point, we have been developing a method for this purpose. It uses a set of 2-port S-parameters of the device under test, embedded in a number of geometrically different RF environments. The application of the method is demonstrated with copper models of TESLA cavities

Transversal loss factor of an rf-focussing iris structure with rectangular holes

By replacing the irises in an electron linac by a slit one gets a structure capable of focussing/defocussing an electron beam (rf-quadrupoles). Therefore one can think of a combination of rf- and conventional magnetic quadrupoles for transversal focussing in linear-colliders. Furthermore they can meet the demands of BNS-damping without initial energy spread. Considering multibunch-operation of a collider, the long-range wake behaviour of this kind of structure has to be investigated. A three-cell structure has been built and investigated for dipole-type transversal long-range wakes. The experimental results are compared to numerical simulations done with MAFIA