Philippe Blache

Stéphane Rauzy

Grégoire Montcheuil

MarsaGram: an Excursion in the Forests of Parsing Trees

Keywords: Typology, Treebank, Syntactic properties, Grammar extraction

The question of how to compare languages and more generally the domain of linguistic typology, relies on the study of different linguistic properties or phenomena. Classically, such a comparison is done semi-manually, for example by extracting information from databases such as the WALS. However, it remains difficult to identify precisely regular parameters, available for different languages, that can be used as a basis towards modeling. We propose in this paper, focusing on the question of syntactic typology, a method for automatically extracting such parameters from treebanks, bringing them into a typology perspective. We present the method and the tools for inferring such information and navigating through the treebanks. The approach has been applied to 10 languages of the Universal Dependencies Treebank. We approach is evaluated by showing how automatic classification correlates with language families.

Introduction

Treebanks becoming available for many different languages (see for example [START_REF] Nivre | Universal Dependencies 1.0. LINDAT/CLARIN digital library at Institute of Formal and Applied Linguistics[END_REF]), they are now important resources especially in a typology perspective. Associating syntactic information to large scale natural data offers both the extraction of regularities and the description of specific realizations of syntactic constructions. Furthermore, thanks to the use of a precise annotation guide, it becomes possible to extract automatically information and apply machine learning techniques to study the distribution of different phenomena. However, the type of information classically encoded into a treebank remains at a high level of generality, that moreover very often remain implicit. For example, constituencybased treebanks encode an implicit phrase-structure grammar, that can be sometimes enriched with the annotation of the main syntactic relations. In this case, in order to render such information explicit, it is possible to automatically extract the grammar from the treebank and identify all the realizations of its rules. On top of this, it is also necessary to describe finer-grained information, such as government phenomena, linear order, cooccurrence, etc., which characterize better a language than the strict set of grammar's rules. The same kind of questions arises in a typology perspective: comparing the grammars extracted from treebanks of different languages is not meaningful per se. On the other hand, typology very often focus only on specific information such as verb/arguments relation or head/modifiers orders. We propose in this article an approach based on a specific representation of the syntactic information, in the perspective of characterizing languages in a typology point of view. This approach mainly relies on a new tool, MarsaGram 1 , making it possible to automatically infer the typological information, independently of the formalism (constituency or dependency). We present in the following the type informa-1 Available on the Ortolang platform, hdl:11041/ortolang-000917 tion that can be extracted and illustrate the approach with different treebanks.

Methods

Infering the context-free grammar of a constituency treebank

The extraction of a context-free grammar (CFG) from a constituency treebank is based on the classic method describe in [START_REF] Charniak | Tree-bank grammars[END_REF]: each internal node of the parsing tree is converted into a rule whose left-hand side (LHS) is the node's constituent tag and the right-hand side (RHS) is the sequence of children nodes' tags. The implicit grammar is formed by the set of such extracted rules. As an example, the figure 1 and 2 show the constituent tree for the French sentence "Elle a dix-sept ans." (She is seventeen.), and the corresponding CFG rules.

SENT

Filtering the rules

Our goal being to extract properties from the CFG grammar, which is highly dependent from the set of rules, the tool integrates different filters according the granularity of tags, the syntactic structures and the rule distribution:

Tag granularity Tags are made of the POS or the phrase type (e.g. Noun, NP) and the syntactic functions (e.g. SUJ). The coarse grain filter conserves only the first level information and then groups syntactic units independently from their function. None elements Some formalisms make use of components without projection in order to represent some linguistics phenomenons (such as ellipsis) or indicate relations between constituents. The none filter suppress these empty elements and their traces in the tree. Coordinations Coordination constructions are frequent phenomena, that multiply the set of realized rules without providing much information on the relations between constituents. The coordination filter reduces expressions that match some prototypical coordination patterns. Frequency A large number of rules (in other words local trees) appear rarely in the treebank, that can introduce noise. The frequency filter remove rules based on a minimal number of occurrences, or their ranks or frequencies among the rules of same LHS.

Experiment

We use in this experiment 4 constituency treebanks, three of them being in the Penn treebank framework: the Penn Treebank itself [START_REF] Marcus | Penn Treebank 2. Linguistic Data Consortium[END_REF] itself, the Chinese Treebank [START_REF] Xue | Chinese Treebank 7.0. Linguistic Data Consortium[END_REF] and the Arabic Treebank (Maamouri et al., 2010a;[START_REF] Maamouri | Arabic Treebank:Part 2 v3.1. Linguistic Data Consortium[END_REF][START_REF] Maamouri | Arabic Treebank:Part 3 v3.2. Linguistic Data Consortium[END_REF] all of them distributed by LDC. We also use the Modified French Treebank [START_REF] Schluter | Modified French Treebank. National Centre for Language Technology[END_REF] a subset of the French Treebank [START_REF] Abeillé | Corpus arboré pour le franc ¸ais / French Treebank[END_REF] developed and distributed by LLF. The table 1 shows the extracted grammars sizes, when applying different filters.

Adaptation to dependency treebanks

We apply a similar approach for dependency treebanks: internal nodes (LHS of the rules) are now the head category, and children nodes (RHS) are the list of dependents, respecting their projection order, plus an extra node with the symbol "*" indicating the head projection. The figures 3 and 4 show the dependency tree for the same French sentence of figure 1 and the CFG rules extracted.

Clit

Inducing the syntactic properties

It remains difficult to explore or compare the syntactic characteristics of various languages using the complete grammar (independently of the formalism, constituents or dependencies). On the other hand, it is possible to compare some specific properties, in accordance with established practices in typology. For example, a classical typology consists in studying the verb/arguments relations and their linearity. We propose to induce from the treebanks some properties used to settle typologies. This properties are identified in the frame of Property Grammar.

Our tool focuses on 4 types of properties governing syntactic components, as described in (Blache and Rauzy, 2012).

Linearity : two components (A,B) have a linearity relation when the occurrence order of these two components is always the same. Requirement : two components (A,B) have a requirement relation when the presence of one requires the presence of the other. Exclusion : two components (A,B) have an exclusion relation when they do not occur together. Unicity : a component A has an unicity property if it never occurs several times in the RHS of the rules with a same LHS.

We note a property as a 4-tuple p =< C, rel, A, B > where C is the context (i.e. the LHS component), rel one of the relations (precede, require, exclude, unicity) and A and B the two components (B = A in the case of unicity).

Validating and violating subsets

In order to infer these properties, for each distinct LHS (syntactic unit or head), we first compile the set of components (i.e. the elements that occur in a RHS). In a second stage, for each pair of components (A, B), we separate the rules where A and/or B occur (together or not) according to whether they satisfy or violate a property as show on the table 2. Starting from these subsets, it becomes possible to consider only the properties that are always satisfied (i.e without any violating rules). It is also possible to relax this constraint and make use of weighted properties, distinguishing between strong (frequent and (almost) always satisfied) and weaker (less frequent and/or more often violated) properties.

Weigthing the properties A first weight w 0 (equation ( 1)) can be directly obtained by calculating the ratio of occurrences of the validating rules to the sum of both subsets -the properties satisfied in all cases corresponding then to w 0 = 1. However, if w 0 allows a first filtering of the properties, it does not provide any information about their actual weight. probable that one of their linearity relation has a w 0 of 1 (or close to 1); nevertheless it would be more relevant to consider the exclusion property even if its w 0 is lower. We introduce then a second weight w 1 (equation ( 2)) that balances w 0 with the frequency of validating rules in relation to the entire set of rules (with the same LHS i.e. Rules(C)).

w 0 = Occ(V alidating(p)) Occ(V alidating(p)) + Occ(V iolating(p))

(1)

w 1 = w 0 Occ(V alidating(p)) σ Occ (2)
Where: σ Occ = r∈Rules(C) Occ(r)

Experiment

This experiment relies on the first version of the Universal Dependency Treebank [START_REF] Nivre | Universal Dependencies 1.0. LINDAT/CLARIN digital library at Institute of Formal and Applied Linguistics[END_REF], a family of dependency treebanks for 10 languages (Czech, German, English, Spanish, Finnish, French, Irish, Hungarian, Italian and Swedish) using an unique tagset : 17 Part-Of-Speech tags based on [START_REF] Petrov | A universal part-of-speech tagset[END_REF], and 40 standardized dependencies relations described in [START_REF] De Marneffe | Universal stanford dependencies: A cross-linguistic typology[END_REF]. As all languages use a common tagset, we can compare the properties extracted from each treebank and define a similarity between two languages based on the proportion of common properties. We build a hierarchical clustering of the 10 languages of the Universal Dependency Treebank (using the hclust function of R). The figure 5 shows the resulting dendrograms either using all types of properties or only the linearity properties (precede). If the first clustering, using all properties does not allow to bring out clear aggregations. The second one, restricted to linearity properties, is more convincing: we find in a same branch the romance languages (es, it and fr), two of the germanic languages (de, sv) -English is grouped with the romances languages before to join the germanic branch -or the two uralic languages (fi, hu) (see table 3 for languages families and features).

Visualizing the data

MarsaGram is also a tool to visually explore treebanks. The program genarates a set of dynamic html pages to navigate, for each LHS, through the elements composing the RHS, the extracted properties and the list of retained and filtered rules. The figure 6 shows a general view of the interface, divided in three part: an index on the left side, the data information on the main part and a visualization of treebank's occurrences in the lower part.

The index lists all symbols of the treebank with their frequency and, for the symbols that are LHS of some rules, the number of associated rules and extracted properties. A link on each LHS symbol loads the corresponding informations on the main part of the windows. The main part offers three combinable "axes" of exploration: the list of symbols composing the RHS part of the rules, the extracted properties and the retained rules. Three tabs allow to switch between these axes as starting point. Then we can progress in the exploration, combining the others axes as show the figures 7 to 10. 10) with more details on the rule: its various variants when some reductions are used (none elements, coordination) and, for each variant, the number of occurrences and their indexes in the treebank, with a link that shows the actual occurrence in the lower part of the windows. When filters are used, another tab allows to inspect the list of filtered rules and access in a similar way to their actual occurrences.

Conclusion

We have presented in this paper the method used to infer properties from treebanks, independently of the formalism (constituency or dependency). This method integrates different filtering options making it possible to tune the properties extraction. An application of this method to the Universal Dependencies Treebank has shown the validity of the approach in a typology perspective: a hierarchical cluster-ing based on a subset of properties led to the reconstitution of language families. The system we have developed in this perspective, MarsaGram, is freely available and integrates as a side effect a possibility to use it as a treebank browser.

Acknowledgments

This work has benefit from the French State support via its "Investissements d'avenir" programs ORTOLANG (ANR-11-EQPX-0032), BLRI (ANR-11-LABX-0036) and A*MIDEX (ANR-11-IDEX-0001-02).

Bibliographical References

  Figure 1: a small constituent tree

Figure 2 :

 2 Figure 2: inferred CFG rules

  Figure 3: a small dependency tree

  Blache, P. and Rauzy, S. (2012). Enrichissement du FTB : un treebank hybride constituants/propriétés (Enriching the French Treebank with Properties) [in french]. In Actes de la conférence conjointe JEP-TALN-RECITAL 2012, volume 2: TALN, pages 307-320, Grenoble, France, June. ATALA/AFCP.

Figure 6 :

 6 Figure 6: MarsaGram interface

  and B occur in the RHS of r and all occurrences of A are before the first B A and B occur in the RHS of r and at least one occurrence of A is after a B < C, require, A, B > A and B occur in the RHS of r A occurs, but B no. < C, exclude, A, B > Only A or only B occurs in the RHS of r Both A and B occur < C, unicity, A, A > Only one A occurs in the RHS of r Various A in the RHS of r

						#rules
						coarse grain
	Treebank	#trees fine grain		reduc(none) reduc(coord)	reduc(none) reduc(coord)	reduc(none) reduc(coord) occ(r) ≥ 2
	PTB (en)	49.786	31.291 17.446	17.120	16.417	16.085	6.867
	ChTB (zh) 51.447	28.128 13.941	14.082	13.509	13.652	5.232
	ATB (ar)	23.488	30.810 16.816	16.669	16.266	16.116	6.945
	MFT (fr)	3.774	6.244	3.363	-	3.300	-	1.391
			Table 1: some context-free grammars sizes
	property p		r ∈ V alidating(p)		r ∈ V iolating(p)
	< C, precede, A, B > A Table 2: validating and violating rules

Suppose that two components (A, B) occur very rarely together: it is highly

  Starting with the list of properties (figures 7, for the verbal phrase (VP), filtered to show only the precede relation), a click on a property open a sub-table listing the various rules indexes that are related to the property, as shows figure8(property < V P, precede, V DB, N P >, where VBD is a verb at past tense and NP a noun phrase). The table shows both the rules validating the property (here the precede row) and the violating ones (here the follow row, with a dark orange background). When the mouse pass over a rule index, the

					Cluster Dendrogram						Cluster Dendrogram
											0.95
		0.75									0.90	ga
		0.70
	Height	0.60 0.65	fi			ga	hu	cs	sv	Height	0.85 0.80	fi	hu	cs
													en	de	sv
		0.55		it							0.75
						de	es						fr
		0.50		en	fr						0.70		es	it
				Figure 5: Comparing languages : all properties(left) and linearity properties(right)
				ud-desc-s1-props-ALLp-nb_prop.csv						ud-desc-s1-props-precede-nb_prop.csv
		Code Language	binary Family	Genre		typologic features	binary
		cs	Czech		Indo-European Slavic		SVO 2 , stress-timed, free word order
		de	German		Indo-European Germanic	V2 and SOV, inflectional, accusative, stress-timed, dy-
										namic accent
		en	English		Indo-European Germanic	SVO, inflectional, accusative, stress-timed, dynamic
										accent
		sv	Swedish		Indo-European Germanic	SVO, inflectional, accusative, stress-timed, pitch accent
		es	Spanish		Indo-European Romance		SVO, syllabic
		fr		French		Indo-European Romance		SVO, inflectional, accusative, syllabic
		it		Italian		Indo-European Romance		SVO, syllabic
		ga	Irish		Indo-European Celtic		inflectional, accusative, VSO, stress-timed, dynamic
										accent
		fi		Finnish		Uralic	Finnic		SVO, free word order
		hu	Hungarian Uralic	Ugric		SOV, free word order, agglutinative, accusative
							Table 3: some languages features
	rule appear as a tooltip, and by a click it is selected to ap-
	pear on a sub-table showing rules and some data (figure 9 :
	occurrences, number of validated and violated properties).
	From these rules data table, a click opens a sub-table (fig-
	ure

SVO, SOV or VSO are the relative order of the Sujet, Verbe and Objet; and V2 stand for the verbe in second position.


Philippe Blache

Grégoire Montcheuil

Stéphane Rauzy

Marie-Laure Guénot

4-Couv, a Backcover Treebank

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Treebanks, that still constitute an essential resource in linguistic description as well as natural language processing, are now faced with new uses, in particular in the perspective of experimental linguistics and psycholinguistics. We present in this paper a new treebanking project (at this stage for French), 4-Couv, aiming at answer the needs of different possible perspectives. Before describing the project, let's underline the fact that only a few truly available treebanks exist for French, mainly the French Treebank (FTB, Abeillé et al. [START_REF] Abeillé | Building a treebank for french[END_REF]) and its derivatives, or the French part of the Universal Dependencies Treebank 1 . However, only few experiments have been done using these resources in the perspective of studying human language processing. They consist in tracking eye-movement when reading texts in the perspective of evaluating difficulty models (on the basis of the number and the length of the fixations). To this day, most of the studies only take into account the morphosyntactic level, such as the works done for English (Demberg and Keller [START_REF] Demberg | Data from eye-tracking corpora as evidence for theories of syntactic processing complexity[END_REF]) or for French (Rauzy and Blache [START_REF] Rauzy | Robustness and processing difficulty models. a pilot study for eye-tracking data on the french treebank[END_REF]), using extracts of FTB. In these experiments however, the nature of the texts could constitute an important bias: they are taken from the newspaper Le Monde, and consist in articles describing the economic situation 20 years ago. They are then of poor interest for a "normal" reader. This problem can induce an effect of "superficial" reading, leading to an important loss of attention as well as an understanding deficit.

In the perceptive of developing such new uses of treebanks, as well as enriching the amount of available data for French, we have created a new treebank based on short texts, semantically consistent and self-contained, and arousing interest so as to maintain the attention during reading.

The treebank is built from a corpus of "backcovers" called 4-Couv, answering all these needs. This project is still under development, a first release will be done by the end of end 2015. It consists in a set of texts from various publishers (Pocket, Gallimard) that gave their agreement. We collected first 8,000 texts, among which 500 have been selected, representing 3,500 sentences.

We present in this article the methodology and the tools that have been developed to create 4-Couv. The first section details the nature of the texts, the characteristics of the annotation scheme and the automatic parsing. The second section outlines the tools used for the selection of texts and the revision of annotations.

The Corpus, its annotations 2.1 The corpus

Backcovers are small texts, containing between 80-200 tokens for 4-10 sentences, generally short (80% of sentences having at most 30 tokens, and less than 10% are longer than 40 tokens). Texts are generally (a) an extract, (b) the synopsis of the story, (c) the genesis of the book, (d) a comment about the work, or (e) a combination of two or three of this elements. Each of these short texts are semantically autonomous and -a fundamental aspect for our purpose -are supposed to keep the reading interest alive, minimizing attention and comprehension drops.

Lexical annotations

The annotation of minimals syntactic units is based on the lexicon MarsaLex2 that associates each form with its part of speech and morpho-syntactic features. The segmentation into tokens is maximal in that highly constrained forms are split into distinct lexical units as long as they follow syntactic composition rules. For example, constituents of semi-fixed expressions such as "il était une fois" (once upon a or "mettre à nu" (lay bare) are split, while other multiword expressions such as "d'autant plus" (all the more) or "tant mieux" (even better) are not, as they do not follow any syntactic composition.

Each lexical category has a specific features set (see figure 1), although many features are common to different categories (typically the gender, number, person). The part-of-speech and feature sets are relatively standard and compatible with most of automatically tagged corpus, and enable to indicate a combination of lexical, morphologic, syntactic and occasionally semantic informations that will have effect on the syntactic construction of upper levels, e.g. the number of a determiner, the subcategorization or the case of a clitic pronoun. We do not have discontinuous lexical constituent, and the tagging is disambiguated (i.e. each element have one part-of-speech, whose sub-categories features could be underspecified when necessary). We do not modify the category of units that change their paradigm ("une tarte maison" (an home[made] pie), "il est très zen" (he is very zen)).

Syntactic annotation

In order to maintain interoperability with the FTB (even though it could be not direct and require some processing), the treebank is constituency-based and syntactic relations are represented by means of trees. We apply the following formal constraints:

• No empty category is inserted in the trees (e.g. in the case of an elliptical construction), each node is instantiated by a lexical or a phrase-level unit.

• We distinguish between lexical and phrase level: we keep unary phrases, e.g. Simone is the unique constituent of a NP in (1).

( • The phrase-level tagset (see figure 2) is reduced to classical phrases, at the exclusion of other constructions such as coordination (at the difference with the FTB and its derivatives).

• The same types of syntactic functions than those introduced for the FTB (see figure 2) are used. This annotation is less precise then other annotation frameworks (such as Gendner et al. [START_REF] Gendner | Les annotation syntaxiques de référence PEAS[END_REF]) where structural and functional informations were given independently.

Parser

The treebank is generated with the LPL stochastic parser3 (Rauzy and Blache [START_REF] Rauzy | Un point sur les outils du lpl pour l'analyse syntaxique du français[END_REF]).

The processing flow follows a classical scheme. After tokenization, POS-tagging is done by means of a stochastic HMM tagger using Rabiner [START_REF] Rabiner | A tutorial on hidden markov models and selected applications in speech recognition[END_REF]. Finally, the stochastic parser generates the possible tree structures and selects the most probable one. The probabilistic model for the POS tagger was trained with the GraceLPL corpus, a version of the Grace/Multi-tag corpus (Paroubek and Rajman [START_REF] Paroubek | Multitag, une ressource linguistique produit du paradigme d'évaluation[END_REF]) that contains 700,000 tokens and which we correct and enrich regularly. In the model the morphosyntactic information is organized into 48 distinct tags (version 2013). On this tagset, the score (F-measure) of the tagger is 0.974.

On its side, the parser has been trained with FTLPL treebank (Blache and Rauzy [START_REF] Blache | Enrichissement du FTB: un treebank hybride constituants/propriétés[END_REF]), a version of the MFT (Schluter and van Genabith [START_REF] Schluter | Preparing, restructuring, and augmenting a french treebank: Lexicalised parsers or coherent treebanks[END_REF]) extracted from the FTB that contains at the moment 1,500 validated sentences with both constituent structure and syntactic functions (around 26,000 tokens).

3 The 4-Couv treebanking tools

Text selector

We have developed a tool helping in the texts selection, in the form of HTML files that comes to genuine autonomous wiki 4 . This strategy to use autonomous HTML files allow to easily distribute the revision work between different experts, without needing to install any particular software (files are working directly in most of web browsers 5 ), neither to connect with a central server (that allows off-line revision). Each file containing 10 texts to evaluate, presenting the book description, the text segmented into sentences, and an evaluation form (containing check boxes and drop-down lists, see figure 3). The wiki syntax renders easy to correct errors in the sentence division (each sentence is a row in a one-column table) or separate the different parts of the text (inserting a blank line). Furthermore, it also proposes to associate information to unknown words and edit the metadata fields.

Revision tools

The correction of the automatic annotations is done in two steps. The first concerns the morphosyntactic tags and the second consists in the revision of the constituents trees produced by the parser.

The morphosyntactic correction tool (see figure 5) presents one token per line, each line containing the form, and a list of possible tags associated to the form, starting with the proposed one. Selecting a new tag consists in clicking another one from the suggested list.

The syntactic correction tool is a tree editor. Only a few of them already exist such as WordFreak (Morton and LaCivita [START_REF] Morton | Wordfreak: An open tool for linguistic annotation[END_REF]) or TrED 2.0 (Pajas and Štěpánek [START_REF] Pajas | Recent advances in a feature-rich framework for treebank annotation[END_REF]). More recently, some "web-based" annotation platforms have also been created, offering an intuitive and fast annotation (brat (Stenetorp et al. [START_REF] Stenetorp | brat: a web-based tool for nlp-assisted text annotation[END_REF]) and sometimes project management facilities (for example by specifying the roles such as annotator, curator or project manager (GATE Teamware (Bontcheva et al. [START_REF] Bontcheva | Gate teamware: a web-based, collaborative text annotation framework[END_REF]) or WebAnno (Yimam et al. [START_REF] Seid Muhie Yimam | Webanno: A flexible,web-based and visually supported system for distributed annotations[END_REF])). However, most of these tools have been developped for dependency-based treebanks. As our approach is constituency based (requiring therefore to deal with a potentially large number of levels), we had to develop a specific editor, that could run in a single HTML (see figure 6) or be integrated into an annotation platform such as brat or WebAnno.

Conclusion

The purpose of this paper is twofold. First it aims to present a new treebank, not only proposing the classical information of this kind of resource in terms of linguistic annotation, but also answering the specific needs of experimental linguistic, in the perspective of acquiring neuro-physiological data on the basis of short and self-contained text. Secondly it also presents new treebanking tools, helping at the different stages of the process: corpus creation, pre-edition, and manual correction of the automatically generated parses. A first resource of 500 texts (3,500 trees) has been created to be distributed, together with the tools, by the end of 2015.

Figure 2 :

 2 Figure 2: Syntactic tagset

( 2 )

 2 "Ce film, Paul et moi on a adoré." (This movie, Paul and I we really do like.)

Figure 3 :

 3 Figure 3: Text selection (description of Vidas/Vies volées, Christian Garcin, edited by Gallimard)

Figure 4 :

 4 Figure 4: Editing sentences split and sections

Figure 5 :

 5 Figure 5: Morphosyntactic tags correction

Figure 6 :

 6 Figure 6: Syntactic tree editor

https://code.google.com/p/uni-dep-tb/

MarsaLex, hdl:11041/sldr000850

MarsaTag, hdl:11041/sldr000841

We customize a TiddlyWiki (http://classic.tiddlywiki.com/, version 2.8.1) that supply the autonomous wiki, and use a Perl script to "fill" each file with the information.

Only a small plugin could be required to save the modified files.

Acknowledgments

This work has benefit from the support of ORTOLANG (ANR-11-EQPX-0032), BLRI (ANR-11-LABX-0036) and A*MIDEX (ANR-11-IDEX-0001-02).


Filipe Quintal
email: filipe.quintal@m-iti.org

Mary Barreto
email: mary.barreto@m-iti.org

Nuno Nunes

Valentina Nisi
email: valentina.nisi@gmail.com

Lucas Pereira
email: lucas.pereira@uma.pt

WattsBurning on my mailbox: a tangible art inspired eco-feedback visualization for sharing energy consumption

Keywords: Sustainability, Aesthetics, Art driven Eco-feedback, User Interfaces, Prototyping

This paper describes a novel art-inspired tangible eco-feedback system. The concept emerged from a workshop with researchers, designers and artists looking at innovative ways to provide more effective eco-feedback that engages users emotionally. The tangible aspect of the system is composed of a set of magnets that users can stick on their physical mailbox outside of their apartment building according to their average energy consumption. The magnets are a total of seven pieces, one for each day of the week. Each piece has a variation of three colors, from green (low consumption) to burning red (high consumption). The magnets are to be displayed in a sequence that represents a typical panorama of local nature. In this paper we report the design and the study we conducted to gauge preliminary results on the system usage and potential. Interviews with participants revealed that none of them felt uncomfortable having their consumption displayed outside. When children were involved in the process they "took control" of the task and pressured their families to perform better.

Introduction

Individual household consumption accounts for a significant part of the total worldwide consumption. For example, two thirds of the electricity used in the United States, 36% of the greenhouse gasses, and 12% of the fresh water consumption [START_REF] Wilson | Buildings and the environment: the numbers[END_REF]. Most people are in fact concerned about the consequences of their actions, however they are also unaware of the impact of their daily activities and more importantly how they can change their behavior to reduce resource consumption. This gap between peoples concerns and behaviors, led to the creation of eco-feedback technologies. Eco-feedback is defined as "technology that provides feedback on individual or group behaviors with a goal of reducing environmental impact" [START_REF] Froehlich | The Design of Eco-Feedback Technology[END_REF]. A challenge when designing feedback about energy consumption, is to relate current actions with the im-pact that they can have in the world, commercial energy feedback systems normally present that information as g of CO2.

Pierce et al [START_REF] Pierce | Energy Aware Dweling: a critical survey for interaction design for eco-visualizations[END_REF] surveyed several publications exploring the impact of eco-feedback technologies in energy consumption and on consumers' behaviors. The authors found out that the use of eco-feedback technology resulted on savings between 5 and 12% of daily energy consumption. They also concluded that when savings didn't happen the eco-feedback was displayed too infrequently (monthly) and hence was disconnected from the consumption behavior. Furthermore studies have show that the savings can relapse over time as the consumers' interest in the feedback device decrease [START_REF] Peschiera | Response-relapse patterns of building occupant electricity consumption following exposure to personal, contextualized and occupant peer network utilization data[END_REF]. Another important finding is that the normal representation of kWh is not informative enough to the majority of the users. Furthermore in [START_REF] Anderson | White: Exploring consumer preferences for home energy display functionality[END_REF] the authors argue that this lack of understanding made users remove those metrics from proposed eco-feedback designs.

In fact the entire electricity infrastructure is designed in way that is hidden to most consumers. With WattsBurning on my mailbox, we want to make the household energy consumption somehow tangible to the users and foster a sense of awareness about it through the action of updating it every day and sharing with their neighbors. By adding it to users routines, we plan to explore the accountability felt by the users.

In the remaining sections of the paper we will present the related work and the WattsBurning concept. In the last sections we describe the deployment of the study, its analysis and the following discussion and conclusions.

2

Related Work

Art inspired and tangible eco feedback

Pierce and Paulos [START_REF] Pierce | Materializing energy[END_REF] argue that feedback systems are to be designed as something tangible as a starting rather than ending point for design inquiry and exploration. That raises cognitive awareness and motivates energy conservation behaviors. In order to provide for this lacking experience, the authors developed Energy Mementos, treating energy as a material that is experienced in a unique and meaningful way. The STATIC! Research institute has developed several tangible eco-feedback devices. Energy Curtain attempts to motivate people to use more sunlight by opening the curtains [START_REF]Static! Increasing Energy Awareness[END_REF]. The feedback is given in colored patterns in a window shade woven. PowerCord, a power aware cord, which was designed to visualize the energy consumed opposed to hiding it. Power Cord glows according to the level of energy that is passing trough [START_REF]Static! Increasing Energy Awareness[END_REF]. Johnson et all [START_REF] Johnson | Watt-Lite: energy statistics made tangible[END_REF] developed Watt-Lite a tangible display of electricity consumption for the workplace. In Watt-Lite, consumption is displayed by the projection of 3 torches to the floor, one represents the real time consumption, while the other 2 represent the maximum and minimum of the day. Using a more abstract approach artists Lena Bllimeier and David Baur, designed the Vision Energy, which is a set of sculptures in order to to "transform the abstract energy consumption process in to a visual adventure" [START_REF] Bllimeier | Vision Energy[END_REF]. In [START_REF] Holmes | Eco-visualization: combining art and technology to reduce energy consumption[END_REF] digital artist Tiffany Holmes reports on her project projecting the visualization of the energy consumption of households in the public space of a building hall (7000 oaks and counting). In Holmes case, digital art is used to display hidden data of real time usage of key resources such as electric appliances in order to offer new strategies to visualize energy in the home and workplace. Another relevant work is presented in [START_REF] Vert | Nuage Vert Project[END_REF] an art installation in Helsinki, in which the city energy consumption was displayed with lasers projected to the smoke of a coal energy power plant. During 7 days the smoke cloud was projected with green colors (the projection was actually the outline of a cloud), the lower the consumption the larger the illumination. In the final day residents were asked to unplug the devices to reduce consumption, to increase the size of the green cloud. This resulted in a reduction of the peak demand in 800 kVA.

Socially enabled eco feedback.

Researchers have used motivators such as social praise or peer pressure to motivate in consumption savings [START_REF] Wood | Energy use information transfer for intelligent homes: Enabling energy conservation with central and local displays[END_REF]. In [START_REF] Foster | Wattsup?: motivating reductions in domestic energy consumption using social networks[END_REF] the authors designed a system to work with the Watson energy monitor 1 . During the study a group of participants were able to consult others consumption while other participants could only view their own. The results showed that the second group managed bigger savings when compared to the fist one, the research team observed that participants were motivated to save energy by the element of competition. A similar study was performed with a mobile energymonitoring tool, the research team observed that participants that shared their energy consumption with others, exchange expertise and troubleshoot problems between themselves [START_REF] Filonik | A customisable dashboard display for environmental performance visualisations[END_REF]. Users engage in comparing and analyzing the others consumption mostly by curiosity. Odom and Pierce [START_REF] Odom | Social Incentive & Eco-Visualization Displays: Toward Persuading Greater Change in Dormitory Communities[END_REF] describe the design and implementation of an ecovisualization design to be used in the Energy Challenge, which was a competition in Indiana University in which students were competing to save water and electricity. The competition resulted in an estimated combined savings of 33.008 KWh of electricity and 724,322 gallons of water compared to baseline consumption. Additionally the research team observed that the consumption behaviors were strongly influenced by their peers, and that social motivation was the key component to the success of the competition.

3

System Description

Household eco-feedback system

The study present here is part of a larger eco-feedback project, which provided families with consumption information via an android tablet. This research platform implements a low-cost non-intrusive sensing infrastructure that is capable of measuring energy consumption and detecting detailed appliance-level data. The consumption information is then made available in the cloud. It allows users to check their real-time or historical consumption data anywhere as long as an Internet connection is available. The system operates in two different modes (see Figure 1), the first one displays real-time data about the consumption (in kWh, €, CO2 emissions), and the second mode is triggered when it goes to idle mode (normally after there is no interaction with device for more than 2 minutes). The second mode comprises a set of digitally manipulated pictures of a local forest landscape that occupies all the screen of the tablet. The landscape picture can change from very healthy green with rainbows and animals, to very sickening dark with fire and without animals, according to how the current consumption compares with the average of a homologous period.

WattsBurning on my mailbox

The concept used in WattsBurning on my mailbox emerged from a workshop where researchers, designers and artists came together to think about innovative ways to provide eco-feedback beyond the traditional informative kWh or CO2 emission displays. Some of the workshops members had previous experience with public communal eco-feedback, in particular the TidyStreet initiative, which was part of the Change project [START_REF] Bird | The Pulse of Tidy Street: Measuring and Publicly Displaying Domestic Electricity Consumption[END_REF].

The brainstorming session revolved around the combination of public (communal) display and using forms of artistic display connecting the energy consumption to elements of the environmental heritage of the local place. Several ideas emerged from the workshop most of the ideas looked at tangible ways of providing and sharing the eco-feedback from the households. The research team agreed that art and playfulness could play a major role in increasing the emotional connection between people, their energy consumption and the long-term effect on the environment. Starting from these ideas the team looked at public spaces that could be used to share the consumption eco-feedback. Since the system (described in 3.1) was deployed on residential apartment buildings the physical mailboxes provided an interesting place to share the consumption, which was both accessible and visible to the larger community. The mailboxes could act as a placeholder for a tangible display of energy information that was at the same time shared with their neighbors. In order to leverage the connection between the in-house system that was already installed and the new shared ecofeedback, the research team brainstormed on different ways to bring the artistic visualization of the consumption. Ideas ranged from using a portrait of the family with different moods, or use a local newspaper to display the consumption, and were finalized on a specific concept: mapping a forest landscape to physical magnets. For the mailbox magnets we used the same forest landscape that was used in the tablet ecofeedback application. (see Fig. 1)..The final concept was taken into different prototyping and evaluation cycles before emerging as the final WattsBurning on my mailbox concept.

Mailboxes Magnets

The system provides an opportunity for family members to share their energy consumption information they already accessed through the android tablet at home, using a shared physical space outside of their apartments. Both eco-feedback visualizations mapped household consumption to the natural endemic forest, which we knew from previous research provided a strong emotional connection in particular with locals and due to several recent extreme environmental phenomena like heavy rain and mudslides or severe forest fires [START_REF] Nisi | Beyond eco-feedback: using art and emotional attachment to express energy consumption[END_REF].

The hardware used to implement the outdoor visualization was based on a set of magnets that participants placed in their mailbox according to their daily consumption. Each magnet represents the consumption of a specific day of the week, referring to part of the full illustration of the local forest at three different health stages: "sick", "normal" and "healthy". The landscape depicted here is a horizontal portion of the landscape present in the tablet system which users were already familiar with (See Figure 1 right). In total each family was given 21 magnets, three for each day of the week with the three different health levels. In addition there was also a banner placed above the magnets with the caption for each day (see Figure 3). Since the mailboxes were made of aluminum (the magnets did not stick to it) a small-magnetized rubber ban was placed in the mailbox through hooks so that the magnets could "stick" to it. Figure 2 shows the banner and the three different landscapes that created the set of magnets for the three different consumption levels. Figure 3 shows how the magnets were placed in the mailboxes.

Evaluation

To evaluate how sharing energy with the mailbox system impacted the perception and energy consumption we selected 4 families for a period of one week to test the concept. The sample families for this study were a sub sample from the families selected for the bigger deployment of the tablet based eco-feedback system (section 3.1). Therefore the families were already used to get information about their energy con-sumption, and they were aware of how their routines impacted the depletion. All the families were couples with children; in 3 of them the kids had less than 12 years. The families lived in two apartment blocks from the same building complex in an urban area of a small city from a southern part of Europe. The mailboxes were placed in the entrance of each apartment block and visible by passers by and neighbors. Users were informed about this study by phone and then scheduled for an interview later to explain how the mailbox system could be used.

Methodology

The mailbox study lasted one week, which we knew, from previous research, was enough to span the routines of a family impacting their energy consumption. Each morning at 7:00 AM the participants received a text message with information about their consumption in the previous day. The text message followed the next template: Good morning Mr/ "Participant name" your consumption yesterday was above/equal/bellow your average for that day of the week, you should proceed to place the magnet assigned for high/average/low consumption.

Then we expected family members to proceeded and place themselves the magnet in the corresponding position at the mailbox outside of the apartment building. At the end of the afternoon one of the researchers passed by the building to check if the participants had placed the magnets correctly (the participants were not aware of this verification). In the following week, we visited the families and conducted a short interview. The goal of the interview was to qualitatively verify if the metaphor used to represent the consumption was well understood, how the family performed the task, and how families felt about having their consumption displayed outside their houses.

Analysis

From our afternoon observations we confirmed that only one of the families skipped the magnet placement in one day. However they placed two magnets in the following day. Apart from that case all the families performed the task on time and correctly (the placed magnet was the correct according to the consumption). All the families found the task of getting the message and placing the magnet simple and reported it didn't interfere with their normal daily routines. They also found the magnets easy to understand. None of the families felt discomfort or concern about having their consumption displayed outside of their apartments and visible to neighbors or passing people: "It was indifferent… I was not at all concerned" (House 1 Mother), although the consumption was only broadly exposed through the color of the landscape slice. When asked if they would feel the same way, if actual consumption data in form of numbers were displayed, instead of the forest representation, families again reported minor privacy concerns, but not strong opposition to it: ".. Of course there could be some privacy concerns… but I don't see any negative aspect with that" (House 3 Father). It is important to note that asking families about a hypothetic scenario, their reaction could be different from their a priori answer once they could actually see the numeric information outside their house.

Particularly interesting reactions to the system came from kids. In one of the apartment blocks the children from the two families that participated in the study were friends, and in both cases they quickly became responsible for performing the task: "He went there before going to school, he asked me for the consumption, and he went there … I have got the stack with the magnets, he chose it before going to school" (Father, House 2), "She went there before leaving to school. She got the magnet from the stack and we stopped in the mailbox before leaving". (Mother House 1).

These statements suggest that competition arised between kids and that unspoken competition soon became apparent to the adults in the families: "It seemed that they were competing with each other... every day in the morning she asked who spend more us or them… at the end she told me Who won?. It was more a competition between them, she was the one reminding me to check the message" (House 1 Mother), "Normally we don't spend without being necessary, but there was a day with higher consumption. He came to asked me why is that? I had to explain him that his mother was cleaning and so on".(House 2 Father).

In the other two families (from a different block), the task was performed by the father, (House 3) and the mother (House 4). The positioning of the mailboxes meant that it was almost impossible for neighbors to ignore each other's consumption. This was confirmed during the interviews, 2 of them were actually curious to check: "I got surprised in the end, our values were close (comparing with the neighbor), but of course since we are comparing savings the actual consumption values could be different)" House 3 Father.

Discussion and Conclusions

Eco-feedback is a promising technology to bring awareness to resource consumption.

In this paper we reported an ongoing study looking at innovative ways to provide ecofeedback that leverage an emotional connection of people with their consumption and the long-term effects while at the same time making use of some playful strategies to raise awareness. WattsBurning on my mailbox provides an interesting strategy for families to display and share their energy consumption. Our preliminary results show that the task of placing magnets reflecting daily energy consumption outside of the houses was not considered hard or a burden by the families. When given the opportunity children become the gatekeepers for the magnets update, and function as probes and awareness aids of the adults about their consumption. We believe that this can provide opportunities for children oriented eco-feedback systems that are more play-ful and stimulate communication about routines and energy consumption patterns inside and across families. Additionally the fact that participants didn't show any concerns about publicly displaying their energy consumption suggests that there is space for exploration in public displaying and sharing of energy consumption. These promising results are inspiring the research team to develop the mailbox concept further and planning a larger deployment that could also lead to more statistically significant results in particular for the long-term effects in terms of consumption and awareness.

Fig. 1 .

 1 Fig. 1. Left:First mode of the tablet application; Right: and second operation mode.

Fig. 2 .

 2 Fig. 2. The 3 different stages of the forest represented by the magnets (banner is on top). 1. Banner with the week days. 2-Forest with low consumption. 3-Forest with medium consumption 4-Forest with high consumption.

Fig. 3 .

 3 Fig. 3. Mailbox of one participant in the beginning (left) and in the end of the study (right)

http://www.diykyoto.com/uk/


Jan Bobeth
email: bobeth@cure.at

Stephanie Schreitter
email: schreitter@cure.at

Susanne Schmehl
email: schmehl@cure.at

Stephanie Deutsch
email: deutsch@cure.at

Manfred Tscheligi
email: tscheligi@cure.at

User-Centered Design between Cultures: Designing for and with Immigrants

Keywords: User-Centered Design, Immigrants, Diversity, Method

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Migration is and was always common at all parts of the world. It´s occurrence is usually influenced by a combination of economic, political and social factors. Supporting the social integration of immigrants in Europe and providing them access to labor markets is essential for the prospective welfare of natives and immigrants. For successful social integration immigrants adapt to basic values and participate as an integral part in the host society, while at the same time maintain their original culture [START_REF] Berry | Immigration, acculturation, and adaptation[END_REF].

Within an international research project we aim to leverage the potential of mobile ICT services provided via smartphones for supporting social integration by offering ad-hoc support (e.g. navigation or real-time translation) as well as long-term training (e.g. mobile language learning). These services are dedicated to overcome the main barriers a newly arrived immigrant has to deal with, when trying to gain ground in an unfamiliar country.

Immigrants moving to countries within the European Union come from all over the world [START_REF]Eurostat Migration & Migrant Population Statistics[END_REF]. Thus, they form a very heterogeneous group and can hardly be treated as one sole target group in terms of service and user interface needs. Their needs differ widely since great variety of user characteristics occurs depending on maternal language, cultural background, education, motivation, duration of stay, religion, and profession. For this reason, it is not expedient to approach all immigrants in Europe at once when designing services for social integration. It is necessary to focus on a narrower definition of the target group. We mainly address Turkish-speaking Turks and Arabic-speaking immigrants from North Africa as they form two large immigrants groups within the European Union [START_REF]Eurostat Migration & Migrant Population Statistics[END_REF]. According to the cultural model of Hofstede [START_REF] Hofstede | Culture's consequences: Comparing values, behaviours, institutions, and organizations across nations[END_REF], the cultural background of both groups differs noticeable from Western cultures (mainly in the dimensions Power-Distance and Collectivism/Individualism). Additionally, we focused on immigrants with low education (up to eight years) and rather short length of stay (up to five years) as these immigrants are potentially exposed to more barriers in everyday live.

Research has shown that cultural differences matter in interface design and affect the data-gathering in a user-centered design process [START_REF] Callahan | Interface design and culture[END_REF]. However, for the special case of immigrants it remains unclear which impact cultural differences between home and host country might have on the outcome of user-centered design processes as well as on interface preferences. By putting immigrants at the center of our research we want to assure that services are needed and useable for the respective target group. Following a user-centered design process (UCD) [START_REF] Vredenburg | User-Centered Design: An Integrated Approach[END_REF], a crucial attempt is to understand the users, their problems as well as their needs and accordant contexts of use. Therefore, the adoption of a hermeneutic approach with qualitative methods seems to be most fruitful for the elicitation of cultural-specific user requirements (e.g. observing and interviewing the concrete target group) [START_REF] Aykin | Cultural Ergnomics[END_REF].

In this paper, we present our methodological experiences gathered within requirements analysis (creating a barriers list, conducting semi-structured interviews) as well as service and interface design (conducting focus groups and participatory design workshops) as parts of the UCD process for and with a selected immigrant user group. We discuss benefits and drawbacks of methods with the goal to formulate concrete implications for successful UCD for and with immigrants.

Related Work

While sociologists have been investigating social integration and cultural differences of immigrants for a long time (e.g. [START_REF] Frindte | Lebenswelten junger Muslime in Deutschland. Ein sozial-und medienwissenschaftliches System zur Analyse, Bewertung und Prävention islamistischer Radikalisierungsprozesse junger Menschen in Deutschland[END_REF][START_REF] Jacobsen | The dual imperative in refugee research: some methodological & ethical considerations in social science research on forced migration[END_REF]), researchers in the domain of humancomputer interaction focused mainly on comparing influences of different cultures (e.g. [START_REF] Callahan | Interface design and culture[END_REF]) instead of targeting immigrants living "between" two cultures. In this section, we present related work from both perspectives. For the elicitation of culturalspecific user requirements Aykin et al. [START_REF] Aykin | Cultural Ergnomics[END_REF] recommended qualitative methods. However, when applying qualitative methods in the work with immigrants several issues arise, such as vulnerability and mistrust towards researchers. The immigration status is very relevant regarding vulnerability and the status may change. Mistrust towards researchers and their work is a general issue for immigrants. Building up trust can require more than application of anonymity, confidentiality, and the use of ethical principles (e.g. by working voluntarily within a nongovernmental organization) [START_REF] Hynes | The issue of "trust" or "mistrust" in research with refugees[END_REF]. For these reasons, it is necessary to maintain a flexible research approach [START_REF] Jacobsen | The dual imperative in refugee research: some methodological & ethical considerations in social science research on forced migration[END_REF]. A researcher is obliged to provide any information about the study, its purpose, and data handling to participants to give them the possibility and the power to decide whether to participate or not [START_REF] Lammers | Refugees, asylum seekers and anthropologists: the taboo on giving[END_REF]. Bloch [START_REF] Bloch | Methodological challenges for national and multi-sited comparative survey research[END_REF] found that asylum seekers were less willing to participate in research than refugees, due to anxieties about repercussions if their responses are given to the local authority. To better understand and reflect the results it is vital to know as much as possible about the study participants (e.g. language and literacy skills, cultural norms, etc.) [START_REF] Bloch | Methodological challenges for national and multi-sited comparative survey research[END_REF].

Regarding concrete methods, self-completion questionnaires have the advantage of being relatively cheap to administer as well as more suitable than face-to-face interviews when sensitive questions are asked or the research itself is sensitive [START_REF] De Leeuw | To mix or not to mix data collection modes in surveys[END_REF]. Faceto-face interviews might be viable to avoid a lacking of answers due to literacy skills [START_REF] De Leeuw | To mix or not to mix data collection modes in surveys[END_REF]. Interviewers sharing ethnic background and mother tongue with the interviewed immigrants might be more successful with sensitive questions [START_REF] Elam | Researching sensitive issues in ethnicity: lessons from sexual health[END_REF]. Talking in mother tongue can also avoid discomfort for the interviewees [START_REF] Blomberg | An Ethnographic Approach to Design[END_REF]. Frindte et al. [START_REF] Frindte | Lebenswelten junger Muslime in Deutschland. Ein sozial-und medienwissenschaftliches System zur Analyse, Bewertung und Prävention islamistischer Radikalisierungsprozesse junger Menschen in Deutschland[END_REF] reported about a multi-generation case study in which interviews, surveys, and discussions were conducted in German, Turkish, or Arabic. Using bilingual Turkish-German and Arabic-German interviewers proved to be very effective and reduced the mistrust of the participants concerning the research.

Method Framework for User-Centered Design

Based on the experiences from related work, we developed a method framework for involving immigrants. However, a big challenge for UCD with immigrants is to find and recruit real users matching the target group definition [START_REF] Aykin | Cultural Ergnomics[END_REF]. Another problem especially in the first phase of the requirement analysis is the establishment of trust between immigrants and researchers [START_REF] Hynes | The issue of "trust" or "mistrust" in research with refugees[END_REF]. For this reason we collaborated with three nongovernmental organizations (NGOs) in Graz (Austria), London (UK) and Madrid (Spain) that are in frequent contact with immigrants and were responsible for the recruiting of all study participants. Being introduced to immigrants by co-workers of the NGOs is already a positive sign for certain trustfulness of for immigrants' unknown researchers. All study participants gave informed consent. In the following we describe how we involved end users and NGOs in the UCD process with the help of qualitative methods (see [START_REF] Aykin | Cultural Ergnomics[END_REF]). Applied methods are explained in chronological order whereas content related results are not reported since this is not scope of this paper.

Barriers List

As contact point for immigrants NGOs have extensive experiences with immigrants' everyday lives, accumulated over years. To learn from these experiences, in the first step of our UCD process co-workers of the NGOs created a list of common barriers for immigrants and related them to age, sex, level of education and length of stay. Lists of the three NGOs were merged and barriers prioritized by frequency of occurrence as basis for setting up the semi-structured interviews conducted subsequently.

3.2

Semi-structured Interviews

By conducting semi-structured interviews, we aimed at gaining deeper insights about barriers and problems in everyday life. Apart from demographic questions, the interview consisted of three parts: (i) questions about social background and qualifications of the interviewees, (ii) motivation for emigration of home country and reasons influencing this decision, (iii) barriers in their personal lives, where they look for support, and whether they could think of mobile services for smartphones supporting them. Bilingual co-workers interviewed the immigrants in their mother tongue (compare [START_REF] Blomberg | An Ethnographic Approach to Design[END_REF] or [START_REF] Frindte | Lebenswelten junger Muslime in Deutschland. Ein sozial-und medienwissenschaftliches System zur Analyse, Bewertung und Prävention islamistischer Radikalisierungsprozesse junger Menschen in Deutschland[END_REF]) in facilities of the NGOs, which were familiar to the participants. The interview protocol and the gathered answers have been translated from and to English. In total, 17 persons have been interviewed in Graz, London and Madrid (10 Arabic and 7 Turkish immigrants). Interviewers were allowed to adapt the order of questions and to dig deeper in some topics based on the tenor of the conversation. One part of the interview was the creation of a relationship map (modified of [START_REF] Moser | Using Probes to create Child Personas for Games[END_REF]) indicating communication behavior of participants to better understand the media usage for talking to important persons in home and host country (see Fig. 1a andb).

Focus Groups

Based on the identified barriers, the interview data and previous ideas of involved researchers various service scenarios have been developed. In order to get feedback on the scenarios and to create additional service ideas, we decided to conduct focus groups as they can reveal surprising insights when conversations take their own dynamic way [START_REF] Skop | The methodological potential of focus groups in population geography[END_REF]. In contrast to the interviews, we decided to include only immigrants who already lived more than three years in the host country and who know the host language well enough for actively taking part in discussion. We also invited a translator to each focus group to provide language support when necessary. The goal of the focus groups was to discuss service ideas by benefiting from immigrants' experience and retro perspective reflection on their problems. We discussed three service scenarios in four focus groups with overall 30 immigrants in the facilities of the NGOs (three with Arabic immigrants in Graz, London, Madrid and one with Turks in Graz).

With respect to the research question, Skop [START_REF] Skop | The methodological potential of focus groups in population geography[END_REF] suggested keeping focus groups homogeneous along certain features, such as sex, age, social class, language, etc. Thus, we did not invite Arabic and Turkish immigrants for the same focus group and conducted two of four focus groups only with female immigrants and researchers. After a short introduction round of researchers and immigrants, we described orally three common barriers out of the barriers list (e.g. needing immediate help in specific situations like filling out forms). After asking and discussing about similar experiences of their own life, we presented three illustrated service scenarios as solutions for the discussed problems by reading the according story aloud (e.g. a service for finding nearby volunteers). Following the presentations, participants estimated whether such a service might have been helpful and what might be improved (e.g. to protect privacy). The focus groups concluded with a general discussion about mobile ICT services as means of support for immigrants. Fig. 1c shows the Arabic focus group in Madrid.

Participatory Design Workshops

To cope with cultural differences in user interface design it is important to actively involve users because most of the existing design guidelines try to raise awareness for the issue but do not offer ready-made solutions [START_REF] Callahan | Interface design and culture[END_REF], especially not for immigrants. For this reason, we conducted two participatory design workshops for co-designing [START_REF] Muller | Participatory design: the third space in HCI[END_REF] with immigrants and two Austrian designers in Graz and London. The goal was to identify and discuss potential differences in design and solution approaches with respect to the immigration background. We invited Turkish and Arabic immigrants who were sufficiently able to speak the language of the host country and lived there for at least three years. In Graz four Arabic speaking women and four Turkish women took part, while in London 8 participants from Arabic-speaking countries joined.

In order to loosen the atmosphere and to stimulate creativity we started both sessions with an introductory game called Trading Cards [START_REF] Gray | Trading Cards. In: Gamestorming. A Playbook for Innovators, Rulebreakers, and Changemakers[END_REF] replacing the usual introduction round. The tasks were (i) to create a personal trading card including name, self-portrait, nickname and special hobbies within 10 minutes, (ii) to present the trading card of another participant to the audience. Afterwards, two illustrated scenarios with additional written descriptions in the host language were distributed. Groups of two were formed to discuss and work on design ideas for the smartphone application "of their dreams" (compare [START_REF] Sanders | Generative Tools for CoDesigning[END_REF]) for one of the two scenarios that each group could choose freely. Therefore, they received smartphone stencils as well as stickers, pencils, markers, etc. After 30 minutes each group presented the created design ideas in front of the whole group for earning feedback. Subsequently, each group of participants redesigned their ideas in additional 30 minutes and presented their final designs.

Discussion and Implications

We present implications of our studies by discussing our experiences with the methods coping with the different cultural backgrounds of researchers and target group.

Collaborating with NGOs. Working in tight connection with the NGOs was of crucial importance. They already had great implicit and explicit knowledge about barriers for immigrants and problems in their daily life. Another crucial aspect is the trustworthy relation between NGOs' associates and the target group. Furthermore, communication in the immigrants' mother tongue -which is possible at most NGOsallows avoiding misunderstandings and is an important factor for creating trust.

Supporting recruiting process. Recruiting participants according to several criteria is a challenging and time-consuming activity, especially for NGOs working with vulnerable groups like immigrants. Trust and motivation may differ widely within the target group. Some immigrants refuse to interact with foreigners in general, while others might not accept that they cannot take part in a study due to formal criteria (compare [START_REF] Jacobsen | The dual imperative in refugee research: some methodological & ethical considerations in social science research on forced migration[END_REF]). For this reason, we kept the number of exclusive characteristics low (see Introduction) although from a sociological point of view this might not be the most accurate way to e.g. provide statistically meaningful statements. Still, some recruited participants did not match all criteria (e.g. level of education).

Benefiting from NGOs experiences. Governmental institutions offer mainly statistical data about immigration problems. In contrast, the barriers list created by the NGOs provided a first authentic overview about everyday problems of immigrants. Such a list can be created with few resources and allows a first prioritization of problems to be addressed. A drawback of this approach lies in the choice of the involved NGOs as their co-workers might have a biased view on the problems of their clients.

For better understanding concrete problems of immigrants, we originally intended to conduct cultural probing which has been applied successfully by other researchers (e.g. [START_REF] Schmehl | Directed cultural probes[END_REF]), though with less vulnerable participants. In our case, the involved NGOs recommended to rely on methods that provide immediate answers as vulnerable groups such as short-term immigrants might have too many other problems than documenting their days. Following the recommendations of the NGOs we conducted semi-structured interviews with immigrants in their mother tongue instead.

Interviewing in mother tongue and more implicit information. Interviews allowed us to gain deeper insights into living circumstances and about potential service needs. Interviewing in the mother tongue of the immigrants created a pleasant atmosphere and allowed easy communication. Probably we would have missed interesting anecdotes when insisting on the host country language and creating discomfort for the interviewee [START_REF] Blomberg | An Ethnographic Approach to Design[END_REF]. A disadvantage of interviewing in the participants' mother tongue is the possibility of translation errors (see [START_REF] Jacobsen | The dual imperative in refugee research: some methodological & ethical considerations in social science research on forced migration[END_REF]), which might be increased by the variety of Arabic dialects. As the main goal of the interviews was to get an impression on living circumstances, vague elements in few translations did not distort the data momentously. Nevertheless, to gather more implicit information about daily routines as input for service ideas methods like cultural probing would have been beneficial.

Benefiting from reflections of long-term immigrants. For a deeper analysis and discussion of service needs, we conducted focus groups with long-term immigrants. They had experienced most of the targeted problems themselves. Thus, they were better able to suggest solutions that could support short-term immigrants than the direct target group itself. Conducting focus groups in the host language and having a translator for language support proved to be effective. Researchers could actively take part in discussions and when participants had problems with formulations the translator could support them. Nonverbal behavior could be observed directly by the researchers (e.g. emotions towards certain barriers or services).

Taking gender issues into account. Concerning gender composition, participants of the two female focus groups pointed out that it was important for them not having to talk to men. Thus, we recommend considering the sex of participants in the selection process for focus groups with immigrants of Turkey and Arabic-speaking countries.

Fostering openness and creativity with playful methods. In the participatory design workshops we experienced the "icebreaker" game Trading Cards working well. Participants got to know each other and the first barrier to talk to the group fell. The game would have been beneficial for the focus groups as well. Basing the discussion on illustrated scenarios facilitated communication between participants and researchers as they concretized the abstract service ideas. The workshops provided little impact on design ideas, but the interaction with immigrants in face-to-face situations was still valuable for the participating designers to understand how immigrants approach design. It might have been beneficial to set a clearer focus on the conceptual design instead of letting participants try to create concrete designs.

Involving researchers with immigration background. A special challenge of working with immigrants in their mother tongue is the translation of research protocols and gathered data. Co-workers of NGOs are not trained in conducting interviews and translating the answers. Thus, they might miss relevant details, and valuable information might get lost. The best solution could be to collaborate not only with NGOs but also with researchers and designers with immigration background or who are based in the countries of origin. This would be especially interesting to better deal with cultural issues in interface design.

Conclusion and Next Steps

To involve vulnerable groups like newly arrived immigrants in UCD is a challenging task. With the help of NGOs as trustworthy partners for immigrants and researchers, we successfully applied a number of methods for analyzing service and interface needs. A list of common barriers created by the NGOs and semi-structured interviews with immigrants supported the researchers to get an overall picture of common problems and to get an impression about living situations. Focus groups and participatory design workshops helped to shape and prioritize service ideas and to better understand design issues. Aim of this paper was to present our implications for other ICT projects involving immigrants in a UCD process. The next steps in the UCD process are the iterative interface design including several usability studies with immigrants and field trials to evaluate the final services. Apart from design challenges like designing Arabic user interfaces also methodological challenges such as investigating influences on usability testing and long-term involvement of immigrants need to be explored.

Fig. 1 .

 1 Fig. 1. a) Interview situation with Turkish immigrant, b) Example of a relationship map created during an interview, c) Focus group with Arabic immigrants in Madrid.

Acknowledgements

This work has been partly funded by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n°288587 MASELTOV.


Peter Lyle
email: p.lyle@qut.edu.au

Hee-Jeong Jaz

Choi
email: h.choi@qut.edu.au

Marcus Foth
email: m.foth@qut.edu.au

HCI for City Farms: design challenges & opportunities

Keywords: Urban Agriculture, City Farm, Design, Sustainability, Urban Informatics

Urban agriculture plays an important role in many facets of food security, health and sustainability. The city farm is one such manifestation of urban agriculture: it functions as a location centric social hub that supplies food, education, and opportunities for strengthening the diverse sociocultural fabrics of the local community. This paper presents the case of Northey Street City Farm in Brisbane, Australia as an opportunity space for design. The paper identifies four areas that present key challenges and opportunities for HCI design that support social sustainability of the city farm: A preference for face-to-face contact leads to inconsistencies in shared knowledge; a dependence on volunteers and very limited resources necessitates easily accessible interventions; other local urban agricultural activity needing greater visibility; and the vulnerability of the physical location to natural phenomenon, in this instance flooding, present a design challenge and a need to consider disaster management.

Introduction

Over half the worlds population now resides in urban spaces, and this is an increasing trend. Urban agriculture is the use of urban and peri-urban spaces for the cultivation and production of food, fuel and livestock [START_REF] Smit | Urban agriculture: an opportunity for environmentally sustainable development in sub-Saharan Africa[END_REF]. Urban agriculture contributes to the ability of cities to provide food to its inhabitants, and offers many positive benefits to society, in the areas of sustainability and health e.g. [START_REF] Odom | Mate, we don't need a chip to tell us the soil's dry": opportunities for designing interactive systems to support urban food production[END_REF][START_REF] Brown | Public Health Implications of Urban Agriculture[END_REF][START_REF] Chopra | A global response to a global problem: The epidemic of overnutrition. World Health Organization[END_REF][START_REF] Howe | Urban food growing: The experience of two UK cities[END_REF]. This domain has been identified as a space that could benefit from new types of HCI technology design [START_REF] Blevis | SUSTAINABLY OURS Food[END_REF], however the limited number of studies mean there is opportunity for exploring urban agriculture from different methodological approaches, including exploring the field as an 'opportunity space' [START_REF] Hornecker | UbiComp in opportunity spaces: challenges for participatory design[END_REF]. This research presents the findings of a case study of the Northey Street City Farm in the city of Brisbane in Australia. A city farm is a term often used interchangeably with community garden, and is a form of urban agriculture that has a specific location and involves a productive farm or garden, run by the local community 1 . Fieldwork was undertaken onsite over six months in late 2011, and was followed by interviews in early 2012 to gain an understanding of the way the farm operates. Participant observation and semi-structured interviews generate data with which to reveal the challenges and opportunities to communication and resource management at the farm. This research forms part of a larger study exploring design opportunities and challenges within different manifestations of urban agriculture within Brisbane.

This approach attempts to provide a clearer picture for HCI designers who wish to engage with city farms. We identify four key outputs as a result of this research that relate to design. The opportunities and challenges described apply to the environments urban agriculture is practiced, far away from the 'standard office environment', as well as the more common limitations and problems that are experienced, designing for volunteer dependant organisations.

Prior Work

Urban agriculture as a subfield of sustainable HCI has previously been reviewed previously [START_REF] Disalvo | apping the landscape of sustainable CI[END_REF][START_REF] Engers | Navigating the terrain of sustainable HCI[END_REF], and the limited studies that explore links between urban agriculture and technology indicate opportunities for innovation to create greater community engagement [START_REF] Odom | Mate, we don't need a chip to tell us the soil's dry": opportunities for designing interactive systems to support urban food production[END_REF][START_REF] Blevis | SUSTAINABLY OURS Food[END_REF]. Urban agriculture was also a partial focus of a CHI workshop that explored design considerations for small scale agriculture and fisheries, focusing on economic and social sustainability [START_REF] Hirsch | Making food, producing sustainability[END_REF].

Locally grown food generates fewer food miles than large scale rural agriculture where food must travel 1500-2500 miles before it is consumed [START_REF] Odom | Mate, we don't need a chip to tell us the soil's dry": opportunities for designing interactive systems to support urban food production[END_REF], although this oftquoted figure has been disputed, and the real value may be much higher [START_REF] Schnell | Food miles, local eating, and community supported agriculture: putting local food in its place[END_REF]. Producing food locally in urban environments is important because it helps alleviate pressure on centralised rural food production to meet the food demands of cities [START_REF] Brown | Public Health Implications of Urban Agriculture[END_REF]. Urban agriculture promotes public health, both with the availability of local fresh producean alternate to refined and processed foods, which contributes to obesity [START_REF] Chopra | A global response to a global problem: The epidemic of overnutrition. World Health Organization[END_REF] and provides physical exercise by engaging in the practice [START_REF] Howe | Urban food growing: The experience of two UK cities[END_REF].

As a key related work Odom [START_REF] Odom | Mate, we don't need a chip to tell us the soil's dry": opportunities for designing interactive systems to support urban food production[END_REF] explored urban agriculture in a similar setting to the focus of this work within Australia. Odom [START_REF] Odom | Mate, we don't need a chip to tell us the soil's dry": opportunities for designing interactive systems to support urban food production[END_REF] by contrast, took the approach of ethnographic fieldwork over several months with two sitesa ground level garden, and a rooftop garden. A continuation of this is Odom [START_REF] Odom | You don't have to be a gardener to do urban agriculture" Understanding opportunities for designing interactive technologies to support urban food production[END_REF], which also investigated different opportunities for design.

Agriculture and technology is also researched as part of ICT4D, although this is not specific to urban environments. Two examples of this in rural India [START_REF] Rege | Designing interactive information access technologies for small scale rural indian farmers[END_REF][START_REF] Patel | Avaaj Otalo: a field study of an interactive voice forum for small farmers in rural India[END_REF] explored methods of giving greater voice and connectivity to farmers.

Case Study: Northey Street City Farm

Northey Street City Farm (NSCF) is a non-profit community organisation and was Brisbane's first community garden, located within two kilometres on the northern side of the CBD. It was started by a group of friends in 1992 who lived in the local area and was supported by the local council. It has since grown to become a non-profit organisation, which employs nine part-time staff, has a separate management committee that gives the farm direction, and a large group of volunteers.

NSCF was chosen for this study as it models several positive aspects that city farms strive for: The location provides fertile land for productive farming; it boasts facilities for practical education through volunteer participation and organised events; and, it offers space to host a local farmers market. NSCF has an established reputation that includes appearances in newspapers and on Australian television 2 . NSCF is financially supported through the following means: community grants, a weekly farmers market, and a plant nursery. These support a diverse range of activities at the farm, which are performed by paid staff and a variety of volunteers. The farm itself is comprised of several functional areas that can be seen on the sitemap in Figure 1 above. There is a paid staff member who is responsible for the management of each area. These include: a nursery, which provides income for the continued operation of the farm; a backyard garden to provide an example of how a typical backyard environment can be utilised for food production; a market garden, where food is grown to be sold at a weekly market, and; a kitchen garden, where food is grown and then prepared in the onsite kitchen, to be consumed by the staff and volunteers who participate at the farm. There are other smaller areas without dedicated staff, such as the composting, native plants, an orchard and a mobile chicken coup, and a new area dedicated to allotment gardens.

At the time this research was conducted, NSCF was undergoing a review process to reflect on the policies and positions of the organisation. The primary author attended one of many meeting of volunteers and staff that discussed the review to resolve potential shifts/redistributions of staff roles and responsibilities.

Methodology

The fieldwork for this study was carried out over the course of three months. It utilised ethnographically oriented methods of participant observation and semistructured interviews to embed the researcher within the urban agriculture context of NSCF. The rationale for this approach is to give a deep understanding of the current operation and communication channels that NSCF utilise to continue functioning. The purpose was to understand the way interaction and communication occurred between people at the farm, and to gain an appreciation of what potential challenges and opportunities HCI designers must consider. The data was then analysed to derive themes from the data, and the key findings are presented in the Discussion section below.

Participant Observation

After completing a 1-hour farm tour (that is run weekly as a means of introducing the farm and encouraging new potential volunteer participation), the primary author then volunteered once a week for two months, working with different groups at the farm. Following this period, the author made the occasional visits on Tuesdays, and the weekend food market on Sundays. This culminated in a number of informal interactions and discussions with staff and volunteers at the site. Observational notes were recorded after the days of participation.

Semi-structured Interviews

Participants for semi-structured interviews (20-40 minutes each) were recruited using a process of snowball sampling. This began with a paid member of the administrative staff, who helped with recruitment suggestions which resulted in five participants overall (a mix of paid staff and volunteers). These five interviews provided sufficient to gain an understanding of the different roles in the farm planning, management and operation, and the nature of communication at the farm. These semi-structured interviews took place onsite at the farm over a period of two days, for the purposes of determining the participant's involvement in the farm, their connection with other members of the farm community, and their connection with other urban agriculture communities. Participants had been involved with NSCF for a period ranging from six months to five years. Two of the participants were current representatives on the Management Committee (in addition to their role as a volunteer and a member of administrative staff), which overseas the general direction of the farm.

Discussion

Analysis of the interview and observation data provided insight into four key areas that could shape potential interventions by HCI designers. These include: a preference for face-to-face communication as a means to share information, often leading to confusion and mixed messages; the dependence of NSCF on the volunteer workforce, and the general resource limitation that requires any intervention to be easily accessible in terms of resource requirement; an opportunity to make other local urban agriculture practice more visible and accessible, while respecting the limited time volunteers and staff have to invest in their gardening passions; and, the need to acknowledge and account for the physical location of the city farm, which is likely to be located on land unsuitable for other high-value uses (e.g. residential or industrial) and in the case of NSCF, is on a floodplain.

Face-to-Face and Inconsistency

Face-to-face is recognised as the prime means of communication at NSCF, as all participants indicated. Face-to-face communication means that information is not always communicated to everyone for whom it may impact, in addition to other issues similar to those identified by Nardi and Whittaker [START_REF] Nardi | The place of face-to-face communication in distributed work[END_REF]. NSCF has different levels of communication that match the hierarchy; there is a management committee, paid staff, team leaders, and a wider circle of people that consists of both paid staff and key volunteers, and then all other volunteers. An example of where the complexities of different groups, have led to inconsistencies is the management of the farm's online presence.

The promotions manager indicated that she was confused as to whether she should be involved in reviewing content before it is made public via the website or Facebook page, as some staff members went directly to the web manager, and other areas of the farm setup their own Facebook pages that were managed independently. The number of other Facebook pages that the interview participants were aware of also differed. Developing technology that can alleviate communication breakdowns, while respecting the preference for face-to-face interaction presents a unique challenge for HCI designers. This could come in the form of a prototype that enables recording of face-to-face transactions, possibly as audio recordings or automated transcriptions. Issues of cataloguing would then need to be considered, given resource limitations described in the next challenge.

Resource Limitations

NSCF is reliant on volunteers to continue operating, despite support from successful grant applications, the nursery, educational operations, the weekly market and annual membership costs. This is unsurprising given that the rise of urban land prices is often a factor in 'pushing' agriculture to the fringe and rural areas. Paid staff are expected to perform volunteer duties in addition to their paid hour allocation. While the space at NSCF is effectively utilised, there is insufficient land for it to operate as a viable commercial farm. Notwithstanding this, the primary focus at NSCF is education and community building, allowing people to learn and participate through volunteering.

In order for the farm to continue it's operation by paying staff, and procuring tools and materials, the farm understandably depends on incoming funds. A lack of surplus money and resources, and a demand to acquire the ability to continue operation means that resource allocation must be performed carefully and efficiently, as there is minimal margin of error. This is a common problem for both starting an urban agriculture project, as well as its continuation [START_REF] Kaufman | The Lincoln Institute of Land Policy: Farming inside cities: entrepreneurial urban agriculture in the United States[END_REF]. HCI designers should consider the overhead of any technologies, as organisations that depend on volunteers such as NSCF are unlikely to consider any investment in new systems. Utilising a participatory design approach may not succeed if the designers themselves are unable to see beyond what is simply said by participants, a problem identified by Bertelsen et al. [START_REF] Bertelsen | Obstacles to design in volunteer based organisations[END_REF]. Taking stock of existing infrastructure, or providing offsite infrastructure as part of any collaboration with a city farm, would have a greater chance of success.

The Bigger Picture of Local Urban Agriculture

All those interviewed expressed interest in other urban agriculture activities outside of NSCF, however only one interviewee indicated they had any time to actually participate. The reasons provided were related to the individual's preference to dedicate all of the volunteering time to a single initiative to encourage and engage with community based urban agriculture. Community based urban agriculture is distinct from that undertaken by individuals in their backyards, which is not necessarily dependent on interaction with others. This limitation of time is not dissimilar to the Resource Limitation point discussed above, however the focus is on the individuals commitment. While participants did not think themselves able to invest time into multiple projects, they were all interested in knowing about other city farm, community gardens and similar community efforts to champion urban agriculture in the local area, providing an opportunity for technology to make this visible. An example might be to provide a geo-mapping experience that can show presents nearby city farms as a map overlay. Sharing expertise and knowledge between different urban agriculture projects, may provide a way to alleviate obstacles for newer initiatives, a problem identified by Kaufman and Bailkey [START_REF] Kaufman | The Lincoln Institute of Land Policy: Farming inside cities: entrepreneurial urban agriculture in the United States[END_REF].

Physical Environment

Urban agriculture tends to be forced out of urban spaces as populations increase, as the relative value of the land increases with higher population densities [START_REF] Nugent | The impact of urban agriculture on the household and local economies. Growing cities, growing food[END_REF], so it is unsurprising that in order to be located so close to the CBD, it is located on flood plain.

Prior to the participant observation, at the end of January 2011 the farm suffered from flooding, causing damage to the farm that meant it was not operational for nearly four weeks. One participant in particular detailed the difficulty experienced keeping the farm operational during this time, and had to setup a remote working environment from her home. A similar problem occurred in January of 2013, with the farm once again flooded. After the floods email communication in addition to the regular farm newsletter was circulated to give an explanation of planned clean-up days, and advised of what facilities or utilities had been damaged (and included requests for donations or replacements). The limitations of the physical environment is consistent with Kaufmann and Bailkey's [START_REF] Kaufman | The Lincoln Institute of Land Policy: Farming inside cities: entrepreneurial urban agriculture in the United States[END_REF] experience that noted the physical setting of urban agriculture projects is subject to a number of issues and constraints, relating to the land (and possible soil contamination), as well as socially driven physical problems of security and vandalism.

As such the ability to manage and mobilise the community in times of natural disasters provides an opportunity for HCI designers to take advantage of mobile technology and telecommuting. This also highlights the importance of proper documentation and backup management of farm resources, perhaps taking advantage of cloud technologies such as Dropbox.

Conclusion

The role of city farms in the broader context of urban agriculture is important as it provides a central physical space for like minded people learn and participate in the process of growing food. HCI designers should consider the positive benefits from a thriving urban agriculture community such as the case of Northey Street City Farm, and take stock of the challenges and opportunities outlined in this paper in order to better share information internally, alleviate resource strains, make visible the bigger picture of local urban agriculture, and prepare for the physical limitations of the environment.

The findings of this paper coincide with that of Odom [START_REF] Odom | You don't have to be a gardener to do urban agriculture" Understanding opportunities for designing interactive technologies to support urban food production[END_REF] and Kaufman and Bailkey [START_REF] Kaufman | The Lincoln Institute of Land Policy: Farming inside cities: entrepreneurial urban agriculture in the United States[END_REF], with regard to the potential value that could be added by improving the visibility of urban agriculture projects, not just to those not engaged, but also to those embedded within existing practice. As part of the larger project of which this study is a part, the future direction is to test the generalizability of the above findings with other manifestations of community (or other non-commercial) urban agricultural practice, such as that of grassroots movements (e.g. "guerrilla gardening", or the permablitz movement), and communities of practice who support each others back or front yard gardening endeavours.

Fig. 1 .

 1 Fig. 1. Northey Street City Farm map provided as part of a guidebook to new volunteers.

Federation of City Farms and Community Gardens, http://www.farmgarden.org.uk/farmsgardens

http://www.nscf.org.au/northey-street-city-farm-in-the-media/ Accessed March 25, 2013

Acknowledgements. This research study is supported under the Australian Research Council's Linkage Projects funding scheme (project number LP100100232).