Linus Feiten

Sebastian Sester

Christian Zimmermann
email: zimmermann@iig.uni-freiburg.de

Sebastian Volkmann
email: sebastian.volkmann@philosophie.uni-freiburg.de

Laura Wehle

Bernd Becker

Revocable Anonymisation in Video Surveillance: a "Digital Cloak of Invisibility"

Keywords: video surveillance, privacy protection, anonymity, data security

Video surveillance is an omnipresent phenomenon in today's metropolitan life. Mainly intended to solve crimes, to prevent them by realtime-monitoring or simply as a deterrent, video surveillance has also become interesting in economical contexts; e.g. to create customer profiles and analyse patterns of their shopping behaviour. The extensive use of video surveillance is challenged by legal claims and societal norms like not putting everybody under generalised suspicion or not recording people without their consent. In this work we propose a technological solution to balance the positive and negative effects of video surveillance. With automatic image recognition algorithms on the rise, we suggest to use that technology to not just automatically identify people but blacken their images. This blackening is done with a cryptographic procedure allowing to revoke it with an appropriate key. Many of the legal and ethical objections to video surveillance could thereby be accommodated. In commercial scenarios, the operator of a customer profiling program could offer enticements for voluntarily renouncing one's anonymity. Customers could e.g. wear a small infrared LED to signal their agreement to being tracked. After explaining the implementation details, this work outlines a multidisciplinary discussion incorporating an economic, ethical and legal viewpoint.

Introduction

Today, life in urban areas is hardly imaginable without omnipresent video surveillance (VS). Screens showing the recorded images are installed in prominent locations to remind us that we are constantly being watched or even recorded. Ideally, this makes us feel more secure; but it might also reveal intimate details about our lives and make us change our behaviour in subtle yet profound ways, thereby threatening our rights to political liberty and personal self-determination.

VS can of course help to convict a criminal, preemptively detect imminent danger, or chase a fleeing suspect more effectively. It is also reported that the visible installation of cameras does in fact reduce crime in that respective area. Thus, from a crime fighter's point of view there are clearly advantages of having as much VS as possible. With more installed cameras the monitoring and evaluation of recorded data becomes insurmountable for human operators. Therefore, efforts are made towards automatising the video analysis through computer algorithms -as it was e.g. the goal of the infamous EU project INDECT.

But not only crime fighters are interested in VS. In an emerging trend, VS has also come into the focus of commercial applications. Similar to internet users being tracked and analysed, people can be automatically identified and tracked on video recordings. Thus, e.g. a supermarket can track the paths customers take through the aisles, analyse where they stop or which advertisements catch their attention. The resulting data allows to optimise the arrangement of products or send customised promotions or discount offers based on the costumer's behaviour. Again, there are obvious advantages of VS in these scenarios: both for the shop owner (optimisation of products and advertising) and for the customers (individual discounts and a more seamless shopping experience).

However, in spite of legal norms governing the allowable use of VS, the public debate on its drawbacks or even threats to an open free society is not ceasing. A most prominent example is the so-called 'Big Brother Award', an annual ironic award by civil-rights activist to persons or organisations who have in their views greatly contributed to shifting society towards George Orwell's dystopia from '1984'. Among the German awardees, there were particularly VS related cases in the years 2000 (German Railways, surveillance of station platforms), 2004 (Lidl supermarkets, surveillance of employees) and 2013 (University of Paderborn, surveillance of lecture halls and computer labs).

In this work, we are discussing a possible reconciliation between these concerns about already present VS and its advantages for both crime fighting and economical endeavours. The 'Digital Cloak of Invisibility' (DCI) is a generally applicable concept of anonymising personal information in vastly collected data [START_REF] Becker | Digital tarnkappe: Stealth technology for the internet of things[END_REF] that is here applied to VS. This anonymisation, however, can be partially revoked if necessary. While there have been several studies about automatic privacy and intimacy preserving in VS and even some about revocable anonymisation, we first suggest an alternative method to achieve revocable anonymisation andto best of our knowledge for the first time -present a scenario of how such a technology could be implemented in a modern society. In contrast to purely technical approaches, this work's main contribution is the multidisciplinary discussion of VS with revocable anonymisation within its societal (legal, economic and ethical) context.

Section 2 outlines the computer scientific details of the DCI, preparing the ground for a multidisciplinary discussion of the approach. Section 3 evaluates VS and the DCI from a legal perspective, exemplarily taking into account the German legislation. In order to provide a more holistic discussion of the societal implications of VS and the DCI, Section 4 discusses the DCI from an economical point of view, while Section 5 provides an ethical analysis of VS and how the respective concerns are met by the DCI. To preserve the scope of this paper, these viewpoints are kept very brief. The intend is to initiate a debate, whose main points and future directions are concluded in the final section.

Technological implementation

The problem of compromised privacy in VS has been addressed by several works; e.g. [START_REF] Cucchiara | A system for automatic face obscuration for privacy purposes[END_REF], [START_REF] Dufaux | Scrambling for video surveillance with privacy[END_REF], [START_REF] Huber | A provably privacy preserving video surveillance architecture for an assisted living community[END_REF], [START_REF] Padilla-Lopez | Visual privacy protection methods: A survey[END_REF], [START_REF] Schiff | Respectful cameras: detecting visual markers in real-time to address privacy concerns[END_REF][START_REF] Senior | Enabling video privacy through computer vision[END_REF]. Most approaches automatically detect and irreversibly obfuscate privacy critical image regions like human silhouettes, faces or car licence plates. Some approaches like [START_REF] Carrillo | Compression independent reversible encryption for privacy in video surveillance[END_REF][START_REF] Cheung | Protecting and Managing Privacy Information in Video Surveillance Systems[END_REF][START_REF] Cichowski | Visual Data Encryption for Privacy Enhancement in Surveillance Systems[END_REF] have also suggested methods for revocable obfuscation. In contrast to these purely technical approaches, this work's main contribution is the multidisciplinary discussion of VS with revocable anonymisation within its societal (legal, economic and ethical) context. We therefore draft a rather simple yet efficient way for revocable image obfuscation; namely to XOR their pixel values with a pseudo-random cipher stream generated from a secret key seed. This scheme is sufficient to demonstrate the relevant concepts of embedding it into the societal context but could also be interchanged for any other possibly more sophisticated reversible obfuscation technique.

As more and more of the recorded video footage is going to be analysed automatically by pattern recognition algorithms, we propose to use the same algorithms to identify persons but blacken them before the footage is stored or viewed by a human. This blackening is done by a cryptographic method that allows to restore the original image with a key. This key is securely stored in the camera and by a publicly accepted key keeper authority (KKA). Whenever video footage is required to identify criminal suspects after an event, the crime fighter requests the required key from the KKA. For cases of imminent danger, a "break glass" functionality can immediately grant a key, leaving a log entry for the KKA to double-check. For commercial applications, the DCI allows shop owners to do their tracking of filmed customers -however, only of those who have agreed to being tracked, similar to the loyalty program 'Payback' where people agree to their shopping receipts being recorded and analysed in exchange for monetary compensation. ('Payback' was incidentally awarded a Big Brother Award in 2000.) People who agree to being tracked could signify their approval e.g. by wearing an inconspicuous tag on their clothes or by inserting a personal smartcard into their shopping cart.

As with classical VS, the recordings are made by a camera we assume to be digital, i.e. the video image is processed by digital circuits before the data is digitally transmitted out of the camera -an assumption that is valid for many VS cameras today and will in the future be true for all VS. The DCI extends such camera with additional internal circuitry that performs a certain post-processing on the video data before it leaves the camera's hardware. The workflow is depicted in Figure 1.

First, an image recognition algorithm identifies all persons in each video frame. The perfectly reliable implementation of such algorithms is nowadays still in its beginning ( [START_REF] Andriluka | Pictorial structures revisited: People detection and articulated pose estimation[END_REF], [START_REF] Benenson | Pedestrian detection at 100 frames per second[END_REF], [START_REF] Dalal | Histograms of oriented gradients for human detection[END_REF], [START_REF] Walk | Disparity statistics for pedestrian detection: Combining appearance, motion and stereo[END_REF]) but most certainly the future will see them running reliably on embedded systems like those of digital cameras. Each DCIenhanced camera has a unique cryptographic key securely embedded in its hardware, called Camera Master-Key (CMK). For each video frame and image region showing a person, an individual Sub-Key (SK) is created by feeding the CMK with frame number and region coordinates to a hash function [START_REF] Shi | Hardware implementation of hash functions[END_REF]. Strong hash functions have the property that the input cannot be derived from the output. Thus, it is not possible to derive the CMK from the SK -even if the used frame number and region coordinates are known.

Generate Sub-Key for each frame and region

Pseudo-Random

Generate pseudorandom bit sequence from each Sub-Key

The SKs are used to generate a pseudo-random cipher-stream of bits that is XORed with the pixel data of the corresponding region in the original video frame. In the resulting video, this region appears obscured (in fact the pixels have random colours). The meaning of pseudo-random is that the generated bits look random, but the sequence solely depends on the respective SK, such that it can always be reproduced. The XOR function (⊕) is reversible:

data ⊕ cipherStream(SK) = encryptedData encryptedData ⊕ cipherStream(SK) = data
Thus, the blackening of a region in a frame can be undone, when the respective SK is known. This is applied in the DCI deanonymisation scheme shown in 2. If a crime is recorded, the crime fighter makes a request to the KKA which verifies its legitimacy and then grants the SKs for the requested frames and image regions. Only the suspect persons in a recording can be deanonymised while all others remain anonymous.

To cater for cases of imminent danger, a "break glass" functionality is implemented such that a sequence of SKs can be requested remotely (e.g. via internet) and is automatically granted. This, however, leaves a log entry with the KKA such that the request's legitimacy and whether the "break glass" was justified can be verified afterwards. In a first proof of concept, we implemented a DCI camera as an opt-out system instead of opt-in. I.e. instead of anonymising everybody by default except those who opt-in, nobody is anonymised except those who opt-out (conceptually similar to [START_REF] Schiff | Respectful cameras: detecting visual markers in real-time to address privacy concerns[END_REF]). This was done to firstly abstract from the person-identifying image recognition. We designed an infrared LED beacon that is picked up by the camera to subsequently anonymise the region around this beacon. Figure 3 shows the practical results. The anonymisation is done with the cryptographic scheme as described above. With sufficiently reliable person-identifying algorithms, the system can easily be transformed into the DCI opt-in variant.

Legal considerations

In 1995, the European Union issued the Data Protection Directive (95/46/EC) to be implemented by all member states. In this section, we exemplarily focus on the German implementation of the directive in its Federal Data Protection Act (Bundesdatenschutzgesetz, BDSG). The legal basis regulating the use of VS ( § 6b BDSG [1]) only allows it under specific circumstances. The VS has to be both sufficient to reach the intended purpose and necessary; i.e. there has to be no less severe economically reasonable alternative [12, paragraph 236]. Furthermore, a weighing of interests must be fulfilled between the intended VS purpose and the constitutional personal rights of the affected (Article 2 paragraph 1 of the Basic Law for Germany), i.e. in particular the right to one's own image and the right to informational self-determination [5, paragraph 22].

The sufficiency of VS is mostly given, insofar as it is assumed to fulfil its typical purposes: crime prevention, detection and deterrence. But also the necessity is generally easy to prove with the argument that high personnel costs are hardly an economically reasonable alternative to the comparably cheap VS equipment [5, paragraph 21]. The weighing of interests is mostly decided in favour of the intended purpose, as § 6b BDSG allows VS to be used for exercising one's right to domestic authority, or -even more generally -to exercise any justified interest for a concretely defined purpose; and justifications -like the state's obligation to avert danger and prosecute crime or the individual's interest in protection of one's property -mostly outweigh the mentioned personal rights of the VS affected, as long as the VS is not done covertly but clearly signified. Furthermore, recordings must not be stored longer than required to fulfil the respective purpose, which of course can allow for rather long time spans depending on the purpose interpretation.

Evaluating the necessity of classical VS versus the DCI, it can be asserted that the DCI is in fact a less severe alternative. As all people are anonymised by default, there is no infringement of personal rights any more. These benefits should outweigh the slightly higher costs in most cases, such that the DCI can also be considered an economically reasonable alternative.

Whether it is also sufficient in the same way as classical VS requires a more thorough analysis. The foremost purpose of VS is to identify recorded suspects in hindsight, which is definitely also provided by the DCI. If recordings are to be analysed in a typically already protracted criminal proceeding, the relatively short delay of requesting the SKs from the KKA does no harm. For emergencies, there is the "break glass" functionality to immediately get a set of SKs. Another purpose of VS is the deterrent effect, which is also catered for by the DCI. Because people will be aware that they will be deanonymised if the crime fighter convinces the KKA of the crime having taken place. This will in most cases be possible by pointing out the respective scenes in the anonymised recordings, because most suspicious actions are still recognisable, even if the "protagonists" are obscured. This is also the reason why DCI-enhanced VS is just as suitable for real-time monitoring. Turmoils or robberies, for example, show typical patterns of movement that are easily spotted irrespective of whether the persons are obscured or not. It can thus be concluded that the sufficiency is fulfilled.

In economical scenarios, where customers renounce their anonymisation in a loyalty program (cf. Section 4), the DCI is legally rather unproblematic. The operator simply has to comply with § 6b BDSG by signifying the use of VS and to let the participating customers sign his general terms and conditions (cf. § 4 and § 28 BDSG).

Of course, this exemplary discussion of the German legal context is not exhaustive and other legal contexts could be included. Furthermore, technical concepts like the DCI have hardly been taken into account in the legal practice. Thus, in addition to the following economic consideration, Section 5 extends the limited normative discussion presented above by including an ethical analysis. This will allow us to look more broadly at normative issues and conflicts introduced by VS and how the DCI can address these in a constructive way.

Economic Applications

DCI systems can not only be utilised for protecting individuals' privacy in the context of VS-based crime prevention and detection. They also allow for conducting economically motivated video surveillance in a privacy-aware manner.

In the following, the potential of the here presented system in the context of customer analysis for marketing in brick and mortar stores is discussed.

Store owners have long used video surveillance systems not only to deter shoplifters but also for being able to present evidence in case of incidents within their premises. However, video surveillance systems are also suited to precisely track customers' movement and even their direction of view [START_REF] Leykin | Real-time estimation of human attention field in LWIR and color surveillance videos[END_REF][START_REF] Liu | What are customers looking at?[END_REF]. This allows shop owners to gain valuable insights that can be used for marketing, e.g. for shop design or advertising campaigns. In Germany, however, customers' high privacy concerns are an impediment to the adoption and usage of such analysis methods. The here presented DCI system has the potential of addressing these concerns on the one hand and to guarantee that only the movements and behaviour of customers who have consented are tracked, on the other hand.

The DCI system can be used analogously and complementary to the currently popular loyalty cards in order to restrict tracking and behavioural analysis within the store to customers who have consented on the one hand, and, on the other hand, to reduce the privacy concerns of customers who have not consented. Two options to harness this potential exist. In its current state of implementation, the presented DCI system can be utilised as an easy opt-out mechanism. Through wearing a respective signal emitter, e.g. on their clothes or on their shopping cart, customers can opt-out of movement tracking and behavioural analysis. However, this application would be in stark contrast to the "privacy-by-design" requirement as laid down in the current draft of the new European General Data Protection Regulation [START_REF]to the processing of personal data and on the free movement of such data (General Data Protection Regulation)[END_REF]Art. 23]. Still, the DCI can also serve as an opt-in mechanism. Customers who consent to being tracked within the store can signal this through signal emitters on their clothes or shopping carts. For example, infrared LEDs could be used in this scenario, emitting light signals that correspond to a customer account or profile. This would also allow for combing the DCI with existing loyalty programs. In that scenario, the VS system would have to encrypt the whole video by default except for regions in which a respective signal is detected. A problem to be solved in the commercial scenario is the selection of an appropriate KKA. Further, the presented system has to be extended in order to prevent "bycatch". In case two customers, one who consented to tracking and analysis and one who did not, are standing close to each other in the store, the will of the customer who did not consent should be prioritised and both customers are anonymised.

Ethical impact assessment

Due to the complex nature of both society and technology development, an ethical impact assessment should not be considered an accurate prediction of the future. Rather, it can be seen as a projection of intended and unintended consequences of technology use and of the potential moral risks and chances. Especially with regard to unintended consequences (side effects) of using new technologies, legal frameworks often lag behind and do not address emerging conflicts adequately. Ethical impact assessment then sketches plausible scenarios and outcomes that can be used as a normative basis for deciding how to deal with technological change in society. In many cases, as done here with regard to the DCI, this normative basis can then be used constructively in the development process. In this way, at least some of the foreseeable moral risks -even if they are not yet fully covered by the legal framework -can be addressed by technological means [START_REF] Petermann | Technikfolgen-Abschätzung -Konstituierung und Ausdifferenzierung eines Leitbilds[END_REF]. 1If we take a closer look at the unintended ethical impact of implementing VS technologies in public places, two argumentative perspectives can be differentiated: (1) the unintended impact can affect specifiable individuals, especially with regard to their fundamental rights and liberties; or (2) the unintended impact can affect the character of a society as a whole, especially by contributing to developments that make it more restrictive. The latter perspective becomes especially important in cases where the impact for most specifiable individuals is comparably small or mostly indirect, but where, in sum, we can still foresee a considerable impact on the openness of society. Examples for this is the subtle but constant expansion of security technologies over a longer period of time (sometimes called the 'boiling frog argument' [START_REF] Trojanow | Angriff auf die Freiheit: Sicherheitswahn, Überwachungsstaat und der Abbau bürgerlicher Rechte[END_REF]) or the ex post expansion of the purpose of data collection ('mission creep argument' [START_REF] Pegarkov | National Security Issues[END_REF]).

In the remainder of this section, we present a brief assessment of the ethical impact of VS with and without the use of the DCI. This is done by means of four metaphors [START_REF]Vision assessment: shaping technology in 21st century society towards a repertoire for technology assessment[END_REF] that are commonly invoked by critics in the relevant public and scientific debates in Germany. 2 Regarding the ethical impact on specifiable individuals, we first look at the commonly perceived risk that the private lives of customers or citizens become "transparent" to commercial and governmental actors (gläserner Kunde/Bürger). Afterwards we discuss the fear that persons under VS are subject to what is called a "generalised suspicion" (Generalverdacht). Regarding the ethical impact on society as a whole, we look at the metaphors of an "Orwellian" and a "Kafkaesque surveillance society".

Individual centric perspective

In the discussion about spatially limited VS in publicly accessible places, the metaphor of the transparent customer predominantly denotes the fear that commercial actors may collect and process data about their customers to an extent that they can infer facts about their wishes, intentions and living situations. Such information often includes private or even intimate facts that are widely considered to be worthy of protection based on cultural norms of modesty (e.g. regarding sexuality or illness) or based on the societal fear that some individuals may be affected disproportionately (e.g. due to their financial or social situation). Furthermore, since intimacy depends on selective sharing of information, the control over information about oneself has been recognised as a necessary precondition to establish relationships with varying levels of intimacy as well as for the development of our personality free from the impingement of others [START_REF] Fried | An Anatomy of Values[END_REF]. In contrast to this, the metaphor of the transparent citizen predominantly denotes the fear of far-reaching data collection and processing on behalf of state actors. Here, the reason for considering certain information private and worthy of protection is founded additionally in the fear of governmental overreach and an overly powerful state. In democracies, therefore, state sponsored VS must always be viewed in relation to rights and liberties that defend the individual against the state. In comparison to commercial actors, state actors are therefore usually subject to stricter checks of proportionality and more often require the implicit or explicit consent of the affected individuals.

In both cases, however, such privacy intrusions are often considered justifiable (especially in a legal sense) if they allow the protection of other societal values -for example if there is the suspicion of criminal activities. Here, the metaphor of the generalised suspicion expresses the fear that security measures such as VS may be used indiscriminately so that all individuals may be subject to privacy intrusions on the basis that some few individuals could be said to have criminal intentions.

In classic forms of VS, individuals can generally be identified either manually or automatically by making use of biometric facial recognition or other optical criteria. In addition to that, the tracking of their movements throughout the area under surveillance can allow to establish buying patterns, to infer personal intentions or to reveal intimate aspects of their living situations. How much time did this customer spend in front of the shelves with the condoms and how often does she come to buy liquor? Does this person commonly use the public transport system during working hours? How long does that man talk to the preacher in the public square, how long to the people from the election campaign? Especially techniques of long-term storage and automated analysis of video data can present a severe infringement of individual privacy and the free development of personality that goes far beyond what people have to assume anyway when they move in public places.

By obscuring the information that allows the identification of individuals in the video images, this moral risk can be mitigated effectively as the recorded data cannot be directly related to specific individuals. Depending on the implementation of the KKA, such an intrusion is only allowed in cases where the reason for it is checked and considered legitimate by an independent instancefor example to collect evidence in case of shop lifting or assault. Furthermore, even in such cases, only specific pieces of information can be revealed, such as data relating to concrete individuals during a specific time frame. At the same time, the intended benefit of the VS -e.g. police officers watching a public area to react quickly in case of assaults or a shop detective watching the customers to spot shop lifters -can still be achieved. Both scenarios show that the usage of a DCI system can protect the privacy and intimacy of customers or citizens much better than classic forms of VS. Furthermore, they allow restricting legitimate intrusions to the necessary information.

Society centric perspective

The term surveillance society is used to express concerns about the prevalence of surveillance measures of commercial or state actors throughout society. In the context of VS, the term does therefore not refer to singular, isolated instances or strictly limited locations, but rather to the gradual proliferation of this measure and the threat that those systems could be networked bit by bit and the recorded information merged to a large pool of surveillance data. In this context, the metaphor of the Orwellian surveillance society denotes the concern that the proliferation of surveillance measures may lead to a situation in which we are almost constantly monitored and where we can never be sure how our behaviour will be interpreted or which negative consequences might ensue later on. From a democratic point of view, this implies the risk that the realisation of some of our rights and liberties may fall victim to a form of self-control -for example because we fear a more negative credit rating or being classified as a high risk airline passenger. This can be seen as a pressure towards a certain standard of normalcy that limits the open character of our society to a considerable extent.

In addition to that, the metaphor of the Kafkaesque surveillance society expresses the fear that we may loose the de facto possibility of achieving an effective remedy in case we suffer illegitimate negative consequences. This is especially relevant in cases where it is highly opaque why the relevant decisions were taken, based on which information and on which criteria and how those decisions can be disputed. With regard to VS measures, this risk becomes material especially in those cases where recorded data is handed over or even sold to third parties without the consent of affected persons, since this would facilitate the consolidation and misuse of data from different sources -for example in order to allow pattern recognition for the detection of potential criminals or insurance risks.

In classic forms of VS, it is very difficult to effectively limit the circulation and processing of the recorded data. Even in cases where signs inform customers or citizens explicitly about the VS, it is almost impossible to foresee what information can be inferred from the recorded data and how it could be used in the future. Some of these risks can be mitigated to a certain extent when surveillance actors promise to restrict themselves in the use of such data -but it is unclear what would be the incentive for commercial actors to do so and how misuse could be sanctioned effectively. The use of a DCI system by commercial or governmental actors, on the other hand, allows the use of the KKA as an independent party to effectively mitigate the risk of circulation, consolidation from different sources and misuse of the recorded data. This is especially true if only those pieces of data are revealed that are strictly necessary for a certain legitimate purpose. Furthermore, for commercial surveillance actors, it could be an incentive for the use of a DCI system if they can advertise their use of higher standards of protection of their customers' privacy. For both the commercial and governmental case, we can thus conclude that a DCI system allows to also effectively mitigate the society centred ethical risks of circulation of surveillance data, of data consolidation from different sources and of misuse of that data.

Discussion and Conclusion

The advantages of a DCI-enhanced VS system over the kind of VS that is already massively in use today has been demonstrated in each perspective of our multidisciplinary discussion. Still, there might be remaining criticisms towards DCI that shall be addressed in the following.

A concern raised from someone generally opposing VS could be, that a DCI technology would merely be a fig leaf for VS; leading to a higher rate of social acceptance followed by an implementation of even more VS systems. That concern would be justified if VS today would in fact be used very sparsely. Reality, however, shows that we are already living in a society where VS is implemented on a large scale, mostly accepted or not pondered over by large parts of the populace. Replacing it with DCI systems will be given just as little thought by those, but people concerned about VS today will experience a real improvement.

Another such concern could be about the DCI security. The whole DCI system relies on the CMK's secure storage both in the respective camera and in the KKA's central storage. If the CMK is obtained e.g. by a hacker attack, all recordings made with the respective camera could be deanonymised. As a precaution, it is therefore recommendable to keep the same strict constraints of how long recordings may be stored that are in place today for classical VS. Then, even if the DCI security should get compromised, it would only be as "bad" as it is right now without DCI. To keep a CMK save in the hardware of a camera there is a manifold of techniques from the field of hardware security and trusted hardware. e.g. tamper-sensing Meshes [START_REF] Anderson | Cryptographic processorsa survey[END_REF] or Physically Unclonable Functions (PUFs) [START_REF] Ruhrmair | Security based on physical unclonability and disorder[END_REF]. Equivalently, the KKA's storage has to be secured with state of the art security measures.

Another question is: "Who is the KKA?" The trust of the populace in the KKA's integrity is essential. Thus, one could consider a democratic board unsuspicious of collaborating with the respective camera operator. We presume that among the civil-rights activist now fighting against VS many would volunteer to be part of a KKA and that they would be trusted; particularly by those sceptical of VS. Another possibility could be a judge or ombudsman to decide about when a key request is granted. In any case, transparency and accountability of the KKA's decisions and procedures are paramount for the creation of trust.

One also has to be aware, that DCI-enhanced VS does not provide perfect anonymity. An obscured person might still be identified by a diligent analyst e.g. by the fact that she was walking a dog or because he was -although anonymised -observed leaving his residency. With an extension of the DCI algorithm these sources of identification could be further hampered, but one should not be illusionary about the limits of anonymisation.

A last concern could come from advocates of classical VS; namely that a DCI is more expensive than classical VS. This is of course true. The extra hardware in the cameras and the administrative efforts to regulate the exchange of requests and keys between the crime fighting instances and the KKA does not come for free. The question we have to ask ourselves as a society is, whether a decrease of intrusion into our privacy and intimacy as well a decrease of infringements of our civil liberties would be worth that extra cost.

Fig. 1 .

 1 Fig. 1. The schematic concept of a DCI camera system.

Fig. 2 .

 2 Fig. 2. Deanonymisation is only possible with the SKs granted by the KKA.

Fig. 3 .

 3 Fig. 3. A first proof-of-concept implementation of the DCI as opt-out: only regions surrounding a detected infrared beacon are anonymised.

Camera Master-Key Sub-Keys Recorded plain data Anonymised data Recorded persons Crime fighter Hash-Function Detect regions with persons Frame 1 Frame 2 Frame 3 Frame 4 Region 1.1 Region 1.2 Region 1.3 Region 2.1 Region 2.2 Region 2.3 Region 3.1 Region 3.2 Region 3.3 Region 4.1 Region 4.2 Region 4.3

Of course, not all moral risks can be addressed technologically and every technological "fix" may introduce new unintended consequences. Therefore, constructive ethical impact assessment should rather be seen as a continuous process of reflection than as providing a static set of design requirements.

[START_REF] Anderson | Cryptographic processorsa survey[END_REF] Although we focus on metaphors from the German speaking debate, the terms translate well and are just as informative for English speaking debates.


H Patricia Mckenna
email: mckennaph@gmail.com

Edges, Surfaces, and Spaces of Action in 21 st Century Urban Environments -Connectivities and Awareness in the City

Keywords:

The purpose of this paper is to introduce a philosophical and phenomenological perspective to complement, extend, and enrich algorithmic and network views of social media in support of connectivities and awareness in the city. The edges, surfaces, and spaces of 21 st century urban environments are explored in relation to how social media is being used to support greater opportunities for awareness and in turn, for more meaningful engagement, learning, and participation in city life. The research design for this study employs an exploratory case study approach, a minimally viable social media space, and multiple methods of qualitative and quantitative data collection and analysis. Anecdotal evidence from informal individual and group discussions conducted in parallel with this study supports further data analysis, comparison, and triangulation. This work makes a contribution to the research literature across multiple domains and a conceptual framework is developed, operationalized, and advanced for connectivities and awareness.

Introduction

The rapid growth of cities is posing unprecedented challenges and opportunities for society [START_REF] Chourabi | Understanding smart cities: An integrative framework[END_REF] and for education [START_REF] Johnson | NMC Horizon Report: 2015 Higher Education Edition[END_REF]. In response, this research explores social media technologies in relation to awareness in 21 st century cities, communities, and commons [START_REF] Mccullough | Ambient commons: Attention in the age of embodied information[END_REF], when used to foster meaningful urban engagement, participation, and learning. Theoretically, this work is situated at the intersection of social media and the information and communication technologies (ICTs) being developed as a strategy for cities to innovate their structures and their communities [START_REF] Nam | Smart city as urban innovation: Focusing on management, policy, and context[END_REF]. As such, this work is concerned with people and their awareness in the context of ICTs as aware technologies in the smart city. Berne [START_REF] Berne | Games People Play: The Psychology of Human Relationships[END_REF] relates awareness to autonomy, claiming that awareness pertains to aliveness. According to Stone, Deci, and Ryan [START_REF] Stone | Beyond talk: Autonomous motivation through selfdetermination theory[END_REF], autonomy "concerns the experience of acting with a sense of choice, volition, and self-determination." Awareness, as it relates to people and learning, "keeps changing all the time" and is "the totality of all experience" for an individual [START_REF] Merton | Learning and Awareness[END_REF]. Using a cityfocused social media space, this work focuses on people and their experience of edges, surfaces, and spaces for action in the city. Vander Veen [START_REF] Vander Veen | Without smart, connected people there are no smart cities[END_REF] comments that "cities without people aren't cities at all" and perhaps Orgos, Inner Mongolia in northern China, described as the world's largest ghost city, provides an example of a city without the intended scale of people [START_REF] Richter | Welcome to Ordos, China: The world's largest "ghost city[END_REF]. This paper is significant because it theorizes and explores awareness and the experience of city life in relation to choice and emerging understandings of the interweaving of physical and digital environments as smart cities. This awareness is particularly critical at a time when Brandt [START_REF] Brandt | Oblivious in the UK? Nearly 100 percent do not notice smart cities growing around them[END_REF] for example, points to a kind of obliviousness in the United Kingdom where "nearly 100 percent" of the citizens "do not notice smart cities growing around them." Further, the philosophical, phenomenological, and theoretical work of Casey on surfaces and edges [START_REF] Casey | Do places have edges? A geo-philosophical inquiry[END_REF][START_REF] Casey | Edges and the in-between[END_REF], combined with a human geography perspective on spaces [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF][START_REF] Beaude | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF], and urbanism thinking [START_REF] Lynch | The image of the city[END_REF][START_REF] Lynch | Good city form[END_REF][START_REF] Jacobs | The death and life of great American cities[END_REF][START_REF] Gehl | Life between buildings: Using public spaces[END_REF] are used to complement and extend the computational and algorithmic understandings of social media [START_REF] Hansen | Analyzing social media networks with No-deXL: Insights from a connected world[END_REF][START_REF] Qi | Community detection with edge content in social media networks[END_REF] in the city. As such, this study looks at how awareness in social mediainfused and technology-rich urban environments may be influencing choice and contributing to meaningful engagement, learning, and participation in city life.

Methodologically, the research design for this study employs an exploratory case study approach, a minimally viable social media space, and multiple methods of qualitative and quantitative data collection and analysis. Content analysis is employed inductively and deductively to gather insights from individuals across the city and from the research literature, respectively. Anecdotal evidence from informal discussions conducted in parallel with this study supports further data analysis, comparison, and triangulation.

What follows is a review of the research and practice literature relevant to the theoretical perspective for this paper, followed by a presentation of the methodology, the findings, discussion of implications, contributions and future directions, limitations and mitigations, and concluding comments.

Review of the Literature

A review of the philosophical and phenomenological literature is presented to complement and enrich the algorithmic and network perspective on edges, spaces, and surfaces in relation to people and social media in the city. In interdisciplinary fashion, a review of the human geography and urbanism literature related to theorizing on edges, space, surfaces, and the in-between is presented, followed by a review of contemporary urban environments in terms of awareness, infrastructure, and experience.

2.1

Edges, Spaces, Surfaces, and the In-Between

A discussion of the research literature on edges, spaces, surfaces, and the in-between is presented from an interdisciplinary perspective across the domains of philosophy, sociology, human geography, urbanism, the socio-material, and the legal/regulatory.

Edges.

In an urban context, Lynch [START_REF] Lynch | The image of the city[END_REF] describes the physical form of cities in terms of five elements -paths, edges, districts, nodes, and landmarks, noting that this contributes to heightening attention and enriching experience. Drawing on the work of Dutch sociologist, De Jonge, on the edge effect [START_REF] De Jonge | [END_REF], Gehl [START_REF] Gehl | Life between buildings: Using public spaces[END_REF] applies the concept to urban areas "where the preferred stopping zones also are found along the borders of the spaces or at the edges of spaces within spaces." Gehl [START_REF] Gehl | Life between buildings: Using public spaces[END_REF] notes that edge zones "offer a number of obvious practical and psychological advantages as a space to linger" concluding that "events grow from inward" as people move from inside a building, to outside, along the façade, and "from the edge toward the middle of public space." Gehl [START_REF] Gehl | Life between buildings: Using public spaces[END_REF] cites the work of Alexander [START_REF] Alexander | A pattern language[END_REF] in the context of "the edge effect and edge zones in public spaces", noting that, "if the edge fails then the space never becomes lively." Casey [START_REF] Casey | Do places have edges? A geo-philosophical inquiry[END_REF] provides an analysis of edges and discusses whether places have edges from a philosophical and phenomenological perspective. Defining places as "any spatial spread ranging from a bioregion or a national territory to a human settlement of any kind," Casey argues that places must have edges in order to be coherent. Casey identifies a relationship for places and edges, claiming that they interact and concluding that places indeed have edges, in the form of boundaries. Further, Casey adds that, "places as well as events" including experiences, "come fully edged." Casey adds that boundaries pertain to other entities including persons, groups, and so on. Characteristics of boundaries are identified by Casey as indeterminate, absorptive, and osmotic, as distinct from borders, as more fixed, precise, and distinct. Casey indicates that, "porous and vague is to allow, and sometimes to facilitate movement" [START_REF] Casey | Do places have edges? A geo-philosophical inquiry[END_REF] and that porous also denotes, to take in and to give out [START_REF] Casey | Edges and the in-between[END_REF]. Where Casey notes that places intersect, Wapnick [START_REF] Wapnick | Why some of us don't have one true calling[END_REF] reminds us that it is at the intersections that innovation occurs. Thwaites, Mathers, and Simkins [START_REF] Thwaites | Socially restorative urbanism: The theory, process and practice of experiemics[END_REF] note that "the two adjacent realms of the edge are not independent but are mediated by it and this means that edges have intrinsic permeability in their capacity for connectivity between realms." Thwaites et al. [START_REF] Thwaites | Socially restorative urbanism: The theory, process and practice of experiemics[END_REF] cite Jacobs [START_REF] Jacobs | Great streets[END_REF] who stated that, "the best streets have about them a quality of transparency at their edges." According to Casey [START_REF] Casey | Edges and the in-between[END_REF] edges are also associated with margins and points of access. It is worth noting that this conceptualization of edges and boundaries gives way to the potential for extension to interactions with social media, the Internet, and other aware technologies.

Surfaces. Discussing urban form in terms of settlement form or the physical environment, Lynch [START_REF] Lynch | The image of the city[END_REF] refers to "the spatial arrangement of persons doing things" and "the resulting spatial flows of persons, goods, and information and the physical features which modify space in some way significant to those actions" citing "enclosures, surfaces, channels, ambiences, and objects." Lynch [START_REF] Lynch | The image of the city[END_REF] refers to continuity as "con-tinuance of edge or surface" using the examples of "a street channel, skyline, or setback." Lynch further claims that "citizens converse, using the surfaces of the city." Schmitt, in Future Cities [START_REF] Schmitt | Information cities. iBook as part of the Future Cities MOOC[END_REF], notes that by looking beyond the surface of a building, a city, or landscape, much more invisible information becomes available that can be used for design and planning purposes.

Spaces. Lévy [27] interprets the concept of spaces as environments and spatialities as actors in the urban context while defining inhabiting as "a successful encounter between space and spatialities." As such, "the various spatialities and the multiple spaces that constitute a society are made compatible and take advantage of each other in a dialogical interaction" [START_REF] Lévy | The Sage Handbook of Human Geography[END_REF]. Thwaites et al. [START_REF] Thwaites | Socially restorative urbanism: The theory, process and practice of experiemics[END_REF] cite Madanipour [START_REF] Madanipour | Public and private spaces of the city[END_REF] who noted that, "in practice, public and private spaces are a continuum, where many semi-public or semi-private spaces can be identified, as the two realms meet through shades of privacy and publicity rather than clear cut separation." Advancing space as "practice, problem, and theory", Lévy [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF] notes that people are space, that "we are constantly changed by space", and that "we constantly change it through our acts." Further, Lévy [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF] claims that we experience and create "contact, remoteness" in between "different kinds of nearness." According to Lévy, people are multi-sensorial; are able to interact with the world in multiple ways; and interact "through immaterial vectors" as in, telecommunications and the Internet as space, contributing to the importance of space in the digital society [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF]. Baude [START_REF] Beaude | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF] articulates how the Internet is a real space that responds to our need to overcome a range of things including distance and time. Baude argues that the space of the Internet is a new type of space and an innovation of space that is continuing to be evolved and remade based on our emerging uses.

In-Between. Casey considers that the in-between is not confined to the surface but rather, "has a depth of its own that is part of the surface itself" [START_REF] Casey | Edges and the in-between[END_REF]. Speaking of transitional edges, Thwaites et al. [START_REF] Thwaites | Socially restorative urbanism: The theory, process and practice of experiemics[END_REF] note that, "in the streetscape, this edge environment is widely recognized as having an important function in framing and forming space in between buildings", citing Jacobs [START_REF] Jacobs | Great streets[END_REF]. Casey [START_REF] Casey | Edges and the in-between[END_REF] argues that edges "open up possibilities" and "come in a plurality of types" and that "when we are in the midst of any activity we are in-between edges," as in, interspace. Casey speaks of "edges of things and events and persons that together constitute the in-between" where activities happen.

Awareness, Infrastructure, and Experience

Hildebrandt [START_REF] Hildebrandt | Prefatory remarks on Part 1: Law and code[END_REF] points to the importance of "how the emerging ICT infrastructure reinvents us" and that "affordances such as a certain degree of autonomy cannot be taken for granted." As such, Hildebrandt [START_REF] Hildebrandt | Prefatory remarks on Part 1: Law and code[END_REF] adds that "actual re-engineering and active participation in the design of the novel architecture of everyday life" are required, providing the context for a discussion of the practice and research literature on awareness, infrastructure, and experience.

Awareness. In an organizational and organizing context, Orlikowski [START_REF] Scharmer | Awareness is the first and critical thing: Conversation with Professor Wanda Orlikowski[END_REF] commented that, "I think people forget they have a choice" and in instances where "people recognize they have a choice they might not act on it" because "the consequences of that choice are often tough." Indeed, Orlikowski [START_REF] Scharmer | Awareness is the first and critical thing: Conversation with Professor Wanda Orlikowski[END_REF] states that "I'm not even sure people are aware that they have a choice" pointing to the importance of context and the identification of three components -"It's awareness, choice, and action." Reflecting on this interview with Orlikowski [START_REF] Scharmer | Awareness is the first and critical thing: Conversation with Professor Wanda Orlikowski[END_REF], Scharmer identifies a link between her work and "that of Arthur, Varela, Rosc, Bortoft, and Nan" in relation to "the different qualities of awareness from which we can choose to act." Lévy [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF] argues that it would be "an error to assign the smallest scale to the individual just because the human body is tiny in comparison with a city." Features such as mobility, multi-dimensionality of the senses (multi-sensorial sensors), and technology-enabled bodily movement "through immaterial vectors" give rise to a vast potential for reach and influence so that humans "are not reducible to the size of their bodies." Here the intersection between people, technologies, and information gives way to emerging and expanding considerations for awareness and action in the city.

A typology of techno-effects was introduced by van den Berg and Leenes [START_REF] Van Den Berg | Abort, retry, fail: Scoping techno-regulation and other techno-effects[END_REF] to expand what they consider is a limited focus of techno-regulation that, "overlooks non-legal forms of intentional influencing on the one hand, and implicit, unintentional forms of technological influencing on the other." The first typology involves the concepts of pervasive technologies, nudge, affordances, and techno-regulation plotted in relation to the level of choice and compulsion on the one hand, and the level of user awareness, where the intention to influence behavior is present. The second typology features the concepts of scripts, anthropomorphisation, the media equation ("eliciting social responses to technology"), and techno-regulation plotted in relation to the level of choice and compulsion, and the level of user awareness, where the intention to influence behavior is unintended, implicit, and automatic. Hildebrandt [START_REF] Hildebrandt | Prefatory remarks on Part 1: Law and code[END_REF] claims that "by providing a framework that goes beyond the usual dichotomy of effective or ineffective technological measures" van den Berg and Leenes "have opened a new field of research" important for "democratic legislators, courts and citizens as well as designers, producers and users of technological artefacts." Acknowledging that the study of techno-effects is "no straightforward matter", van den Berg and Leenes [START_REF] Van Den Berg | Abort, retry, fail: Scoping techno-regulation and other techno-effects[END_REF] caution that "predicting techno-effects always ought to be a contextual, technologydependent matter" given the characteristics of different technologies along with variation of use by technology and user group.

Infrastructure. Cohen [32] identifies three generations or waves of the smart city with the current or third wave as Smart Cities 3.0 involving co-creation. Where 1.0 focused on the technology-driven smart city and 2.0 is city-driven, Cohen sees promise in a combination of all three. Leveraging 2.0 to enable and encourage urban entrepreneurship, Cohen advises that "cities must move from treating citizens as recipients of services, or even customers, to participants in the co-creation of improved quality of life." Expanding upon the notion of stocks and flows of goods and services, Lévy points to the importance of "stocks of experience and acting capacities" of people in urban spaces [START_REF] Lévy | EPFLx: SpaceX Exploring Humans' Space: An Introduction to Geographicity[END_REF], a possibly relevant way of thinking about awareness and further endorsement for the emphasis placed on action and choice by Orlikowski [START_REF] Scharmer | Awareness is the first and critical thing: Conversation with Professor Wanda Orlikowski[END_REF]. Dourish and Bell [START_REF] Dourish | Divining our digital future: Mess and mythology in ubiquitous computing[END_REF] remind us that infrastructures are "normally taken for granted" and that "new technologies inherently cause people to reencounter spaces." Inverse infrastructure described by Egyedi and Mehos [START_REF]Inverse infrastructures: Disrupting networks from below[END_REF] as ad hoc, user-driven, adaptive development from the bottom up, broadens the potential scope of agency and involvement [START_REF] Angus | Public goods: Using pervasive computing to inspire grassroots activism[END_REF] and opportunities for awareness, choice, and action.

Experience. Dourish and Bell [START_REF] Dourish | Divining our digital future: Mess and mythology in ubiquitous computing[END_REF], [START_REF] Dourish | The infrastructure of experience and the experience of infrastructure: Meaning and structure in everyday encounters with space[END_REF] refer to the transformations that are emerging in terms of how "we experience and interact" as computation increasingly moves "off the desktop and into the world" around us "as an aspect of the everyday environment." The world of embedded and wearable technologies is explored by Dourish and Bell in relation to implications "for encounters with space" where space is held to be an infrastructure for both technology and the "experience of the world" [START_REF] Dourish | Divining our digital future: Mess and mythology in ubiquitous computing[END_REF]. Thwaites et al. [START_REF] Thwaites | Socially restorative urbanism: The theory, process and practice of experiemics[END_REF] claim that "the properties of permeability and transparency are closely related" where the latter "enables us to experience the interplay of 'here' and 'there' by means of features which allow us awareness of nearby settings."

Summary

In summary, complex issues pertaining to aware technologies in urban environments give rise to the need for philosophical and phenomenological perspectives on edges, surfaces, spaces, and the in-between to complement and extend algorithmic and network perspectives. Additionally, the urbanism literature provides insight for leveraging social media interactions and discussions in the city in relation to awareness, infrastructure, and experience. As such, this review of the literature provides the theoretical perspective for formulation of a conceptual framework, depicted in Fig. 1, to guide exploration of the research questions for this study in terms of connectivities and awareness involving choice and action. Q3: What is the nature of the relationship between connectivities and awareness for choice and action in contemporary urban spaces?

Propositions corresponding to the research questions are as follows.

Propositions. P1: Edges, surfaces, spaces, and the in-between contribute to greater awareness in relation to choice in contemporary urban environments.

P2: Social media and other aware technologies contribute to emerging understandings of urban infrastructures fostering opportunities for action and choice in contemporary smart city environments.

P3: The experience of evolving urban infrastructures contributes to greater connectivities in support of greater awareness, influencing choice and action in the city.

Methodology

The research design for this study employs an exploratory case study approach incorporating multiple methods of quantitative and qualitative analysis. This study spans a 7-month timeframe from mid 2015 into 2016, across multiple small to medium to large sized cities in Canada and extending to northern Europe. Interest and involvement was sought from people 18 years of age and older. In parallel with this study and beginning 5 months earlier, anecdotal evidence was gathered over a 1-year period through informal individual and group discussions with people across the city. The methodology is described in more detail in sections 3.1 to 3.3 in terms of the process used, sources of data collection evidence, and the analysis of data.

Process

This study invited a cross-section of people in the city in the use experience of an interactive, city-focused, minimally viable social media environment. Study participation accommodated individuals across six categories: city officials, business, community members, educators, students, and visitors to the city.

After registering for the study and sharing minimal demographic data (e.g., age range, urban location, and self-identification in one or more of the six categories), participants were assigned an anonymous alpha-numeric identifier and invited to share information about their city pertaining to noticing and ideas. Content contributed to the social media webspace was available for viewing, comment, and interaction by participants in real time. Follow-up, in-depth interviews and an optional online survey were used to explore the research questions under study.

Data Collection

This study utilized multiple methods of quantitative and qualitative data collection, including webspace activity, a semi-structured online survey, and in-depth interviews. Interviews focused on use experience with the social media webspace, content creation, and questions related to smart and aware cities. Anecdotal evidence [START_REF] Cubitt | Anecdotal evidence[END_REF] was gathered from people across the city in parallel with this study, through informal group and individual discussions conducted in local coffee shops, online/phone, and in urban workshop and other informal group spaces.

Analysis of the Data

Quantitative data analysis included the use of descriptive statistics. Content analysis was employed inductively for qualitative data emerging from interviews and discussions and deductively, drawing on terms from the research literature to guide data analysis. Anecdotal evidence from informal discussions gathered in parallel with this study supported further data analysis, comparison, and triangulation. Overall, data were analyzed for an n=16, spanning age ranges of people in their 20s to their 70s, and included a gender representation of 55% male and 45% female.

Findings

Findings are presented in sections 4.1 to 4.3 in relation to the research questions, focusing on the three propositions explored in this study. A summary of findings is provided in section 4.4.

P1: Edges, Surfaces, Spaces & the In-between: Awareness

Common throughout interviews and discussions with individuals and groups was the concern with the face-to-face and the non-physical and how the two realms work together. For example, a city councilor emphasized that "its important to think of technology as a tool" and as an aid and an augmentation that "allows us to have a safer more vibrant city." An educator pointed to physical spaces in the city, such as a fountain, to bring people out and together. And a community member identified a range of intersecting modes of transport that can be used to move from point A to point B. A local community placemaker talked about ad hoc, pop-up events, stating that, "we like to do those to demonstrate how a space can change" and to "look at any given

space and analyze what's working and what isn't and what could improve it."

The importance of multi-purpose spaces was identified by one participant who stated that, "the survival of cities is that they are these multi-purpose spaces." Thinking about surfaces in the city, an educator questioned whether the corporate advertising on a local building display screen could be "seen differently" in terms of purpose. A government official used Oldenburg's [START_REF]Celebrating the third place: Inspiring stories about the "great good places" at the heart of our communities[END_REF] notion of a third place to refer to coffee shops as the space in-between "home and work." This in-betweenness is further de-scribed as the connectivity that occurs between people. Referring to routes of connection in Toronto, a community member noted that "you have so many different choices" of getting from point A to point B, "depending on the weather, the traffic, who you are with." So, "the city allows you to make choices about how you are going to get from A to B" and additionally, "its not just allowing you to make choices" but enables "customizing your own experience." For example, "a series of underground liveliness" including tunnels and walkways were described where, "the city is allowing you to play in it" contributing to a "game aspect." From a technology perspective, a business-person spoke of connectivity enabled by GPS (global positioning systems) within the city as outside-in and more recent GPS developments within buildings in the city as inside-out. With the increasing pervasiveness of connectivity, this individual observed that "everyone could work at home but they choose not to" as witnessed by the emergence of businesses renting shared urban workspaces.

P2: Social Media and Aware Technologies: Infrastructures for Action

A city councilor recalled that, "we held our first interactive e-TownHall" featuring a discussion of the strategic plan for the city. So, in addition to the face-to-face meeting at City Hall, "we were able to get feedback from people sitting at home who were watching the livestream video." The councilor later commented that the social media space would be "one place where we will be looking to use online tools" in the development of a youth engagement strategy. The space of conferences was described by an educator in terms of bringing people together from around the world. When a conference session uses a speaker background screen of Twitter feeds it was acknowledged that, "you've got 500 people at a conference but you've actually got 5000 that are participating in that conference through the Twitter feed." In the case of the interactive e-TownHall meeting, a city councilor noted that, "not only did we have a packed house in person" there was "also, an overflow room" that "had hundreds of people watching the video, tweeting, sending direct messages that we could respond to." As such, social media was described by the city councilor as able to, "definitely create discussion and connections." An urban placemaker used the example of a blog as social media where a post about "library boxes" resulted in unexpected interest and interactivity, contributing to an interweaving of Twitter activity, Google mapping, new connections, engagement and participation, 'things' in the form of books, and video sharing.

P3: Urban Infrastructure: Connectivities and Awareness for Action

The importance of an elaborate fountain in an urban space was described by an educator in terms of how people gather in this space, take notice, speak to each other, pause, and interact. The fountain was described as a touchstone that "brought people out" where they would say, "did you see that, did you see, look at how neat that is."

The fountain also contributed to 'fun' and "made people talk." The erecting of temporary overflow spaces by the city, in multi-purpose fashion, outside a main sports event in Toronto using a giant jumbotron television screen was identified by a community member as "bringing a city together," accommodating up to ten thousand people in an urban space. A European educator described a "mobile cloud-based app to capture and share insights, feedback, and knowledge" as a "simple, cost efficient" mechanism for "instant awareness" intended for "business, design, infrastructure, learning, safety, sport, and tourism." An urban placemaker described "ways to animate a space" using the example of a city parkade with embedded sensor technology that "plays different sounds as you go up based on where you are in the stairwell" and the "lighting changes." An educator in Finland commented that, "one thing I really like about the city is that it is compact" with "smart construction, including lights" aiding flows of traffic and pedestrians.

In the context of a discussion about inverse infrastructure initiatives, a technology entrepreneur articulated the plight of taxi drivers paying high fees in adherence with regulatory requirements, now confronted with a largely unregulated Uber travel movement. An individual in the tourism sector argued that the Uber travel movement is creatively "piggybacking on someone else's infrastructure in a way that is win win." An engineering student identified an interest in speaking with local government and community members to look for "an opportunity maybe for making the city a little smarter" motivated by the hope of changing "people's minds so they follow a more green way." A business technology entrepreneur highlighted the importance of the "smart city thought process" as a "wonderful thing that connects all the pieces," including "people, community." Another educator suggested, "lets spend less time finding the connection" and more time "actually making it," adding that people "choose to live somewhere" attracted in part by "smart infrastructures" and more livable lifestyles.

Summary

In summary, Table 1 provides an overview of findings pertaining to the research questions and the three propositions under exploration in this study in relation to connectivities, awareness, choice, and action. Proposition 1, encompassing edges, surfaces, spaces, and the in-between, was found to contribute to connectivities, awareness, choice, and action in the city. Similarly, proposition 2, encompassing social media and other aware technologies was also found to contribute to these four elements, as was Proposition 3, encompassing urban infrastructures such as mobility, public spaces, and multi-purposefulness.

Discussion

A discussion of the findings is presented in sections 5.1 to 5.3, organized in terms of three components: connectivities; awareness; and the infrastructural elements of edges, spaces, and surfaces for action and choice. A summary of the discussion follows in section 5.4.

Connectivities

Where urban spaces bring people together and encourage talking and interaction, the possibilities for connectivities were found to extend to other urban spaces as evidenced by the e-TownHall example provided by the city councilor, enabling participation through video connection, Twitter, and other social media spaces. The example provided by an educator of conference presentations accompanied by live Twitter feeds, demonstrated the potential for global connectivities involving many people in addition to those physically attending the event. The sports event where the city created a temporary, community-accessible overflow space for thousands of people, aided by jumbotron screens broadcasting the inside event to the outside audience, demonstrates the adaptive and ad hoc creation of urban public spaces for interaction, community connection, and any number of creative initiatives. Pop-up, ad hoc events organized by urban placemaking networks, in conjunction with city officials and many other people in the community, demonstrate temporary alterations and interactions with infrastructure, enabling emergent connectivities with the potential to influence action, awareness, and choice, going forward.

Awareness

Engaging people in discussions about noticing, idea generation, and the use of social media and other aware technologies in the city revealed considerable interest in awareness about the city, smart technologies, and the smart cities phenomena.

Where urban spaces can be designed to bring people together and encourage talking, connection, and interaction, the possibilities for awareness also emerged around the interweaving of such spaces with social media and other aware technologies. In a world where increasing numbers of people carry or wear a mobile device of some type, the potential for additional awareness generation emerges. For example, the blog about "library boxes" generated action and awareness in the form of tweets, photos, video, Google maps, and other mixed media. Thinking about surfaces in the city, an educator commented that the corporate advertising on a local display screen could be enhanced for more informative purposes beyond advertising, "if it was used differently." Used differently, public display screens can become spaces for deeper information sharing, content generation, awareness, interaction, and action.

5.3

Edges, Spaces, and Surfaces for Action and Choice

The social relevance of urban edges [START_REF] Jacobs | The death and life of great American cities[END_REF] was found to extend and become interwoven with edges, spaces, and surfaces for action involving the use of social media and other aware technologies. For example, the realization emerged that conference spaces have the potential to attract many more visitors when presenters open presentations to social media spaces such as Twitter. As such, the space for action, experience, and choice broadens, enabling new forms of engagement, learning, and participation. In a moment of realization about the interactive e-TownHall meeting, a city councilor commented that, "so in that way, that is an interactive experience that makes the city more real for those people." Discussion of the Uber travel movement in the context of inverse infrastructures enabled information sharing and new awareness and insights to emerge. Urban spaces were found to become multi-purpose beyond traditional, physical notions, to incorporate the innovations in space afforded by the Internet, social media, and other aware technologies. Indeed, content generated in multi-purpose urban spaces opens the way for further multi-purpose potentials. As the spaces, edges, and surfaces of the physical are made to connect and interweave with the spaces, edges, and surfaces of the online or the 'immaterial', the intermingling of realms enrich and enliven each other, enhancing connectivities on the one hand and the potentials for awareness, choice, and action on the other. This intermingling offers opportunities for the evolving and enriching of relationships and partnerships across the city where barriers may previously have existed.

Summary

In summary, this work explored the potential for shedding light on, beneath, beyond, and around urban edges, surfaces, spaces, and in-between-ness in relation to emergent infrastructures of connectivities and awareness enabled through social media and other aware technology experiences, interactions, and activities in the city. Findings highlighted in Table 1 (section 4.4) point to the interweaving of different types of infrastructures in the city and to the enmeshing of people and technologies within, between, and beyond urban edges, spaces, and surfaces. The four parameters -connectivities, awareness, choice, and action -are affirmed with a check for each of the three propositions. As such, this study highlights and reaffirms the importance of the people, technologies, and cities dynamic of smart cities [START_REF] Nam | Conceptualizing smart city with dimensions of technology, people, and institutions[END_REF][START_REF] Mckenna | Rethinking learning in the smart city: Innovating through involvement, inclusivity, and interactivities with emerging technologies[END_REF], shedding light on the importance of human awareness, choice, and action about the use of aware information and communication technologies (ICTs). This exploration of edges, spaces, surfaces, and the in-between identifies new possibilities for action and choice in relation to connectivities and awareness. As such, this work operationalizes the conceptual framework for urban connectivities and awareness depicted visually in Fig. 1 (section 2.3) as an approach intended for broader use in the city. This work extends edge, space, and surface theorizing in urban environments to social media, Internet, and other aware spaces enhancing connectivities and awareness in the smart city. As actors in the urban context, new understandings of people as forming part of, and contributing to, the critical infrastructure in smart cities emerges. As such, Dourish and Bell's [START_REF] Dourish | The infrastructure of experience and the experience of infrastructure: Meaning and structure in everyday encounters with space[END_REF] infrastructure of experience finds a home in smart cities and it is this human infrastructure, consisting of the critical components of connectivities and awareness, that serves to possibly moderate and provide balance for concerns with techno-effects [START_REF] Van Den Berg | Abort, retry, fail: Scoping techno-regulation and other techno-effects[END_REF] and the theme of this Human Choice and Computers (HCC12) conference -technology and intimacy: choice or coercion.

6

Contributions and Future Directions

Limitations and Mitigations

Limitations of this work associated with small sample size are mitigated by in-depth and rich detail from a wide range of individuals across small to medium to large urban centers. The minimally viable social media webspace presented challenges that were mitigated by additional information sharing during in-depth interviews. Anecdotal evidence collected from informal individual and group discussions conducted in parallel with this study, contributed added rigor through further data analysis, comparison, and triangulation and is considered to be an important source of data by Trochim [START_REF] Trochim | The qualitative debate[END_REF] and others [START_REF] Cubitt | Anecdotal evidence[END_REF].

Conclusion

In conclusion, through the use of an edges, surfaces, and spaces lens incorporating a an interdisciplinary perspective, this work contributes to a discourse on the importance of fostering opportunities for awareness among people about cities and smart technologies. Using a minimally viable social media space, this study introduces an emergent environment for exploring connectivities and awareness in contemporary cities. This work makes a contribution by advancing a theoretical perspective to complement and enrich computational, network, and algorithmic views of social media by extending edge, space, and surface theorizing in urban environments to social media, Internet, and other aware spaces for enhancing connectivities and awareness in the smart city. Second, this work contributes to the research literature across multiple domains, such as awareness, choice, and smart cities. Third, a conceptual framework is developed, operationalized, and advanced for awareness, choice, and action in 21 st century urban spaces offering a perspective on connectivities and awareness that features an interweaving of aware people using aware technologies, as a way of possibly mitigating 'techno-effects' and concerns with the choice or coercion dilemma. Fourth, in developing new understandings of the potentials associated with the interweaving of connectivities and awareness across physical and electronic spaces, this work is expected to open discourse areas for awareness research in relation to smart cities. Finally, this work identifies future directions and opportunities for practice in terms of awareness, choice, and action and for research in terms of a conceptual framework for awareness, choice, and action, and awareness and choice in smart cities research.

An important take away from this work is the emphasis on the importance of people, physical spaces, and the innovation of space afforded by social media, the Internet, aware technologies, and the Internet of Things (IoT). Taken together, this highly interwoven dynamic -people-technologies-cites -gives way to the potential for more balanced approaches and opportunities for action and choice enabled by connectivities and awareness. This work will be of interest to practitioners and researchers and will have implications for culture, policy, privacy, and sharing. Educators, city officials, urban planners and developers, awareness researchers, and anyone concerned with innovating infrastructures and relationships in support of vibrant, sustainable, and livable communities and cities will be attracted to this work.

Fig. 1 .

 1 Fig. 1. Conceptual framework for awareness, choice, and action in 21 st Century Urban Spaces

Table 1 .

 1 Proposition findings: Connectivities and awareness for choice and action in the city.

	Connectivities Awareness Choice Action

6.2 Future Directions for Research Awareness, Choice, and Action in 21 st Century Urban Spaces. The

  This paper makes several contributions relevant to research and practice. First, this work contributes to the research literature across multiple domains, including but not limited to awareness, choice, and smart cities. Second, a conceptual framework is developed, operationalized, and advanced for awareness, choice, and action in 21 st century urban spaces. As such, this framework offers a perspective on connectivities and awareness featuring an interweaving of aware people using aware technologies, as a way of possibly mitigating 'techno-effects' and concerns with the choice or coercion dilemma. Third, in developing new understandings of the potentials associated with the interweaving of connectivities and awareness across physical and electronic spaces, this work is expected to open discourse areas for awareness research in relation to 21 st century cities. As such, this work identifies future directions and opportunities for practice and research. Offering an alternative view of the concept of edges, edgefulness, surfaces, spaces, and the in-between in the context of aware people using aware technologies, this work offers insight into the potential for choice and action in urban environments. As such, opportunities emerge for initiatives fostering more meaningful engagement, learning, and participation in city life. conceptual framework for awareness, choice, and action in 21 st century urban spaces advanced in this paper is intended for broad use by: educators, researchers, city officials, and many others. This framework will benefit from further use and development going forward, with the potential to open the way for new research and practice approaches and opportunities.

	6.1	Future Directions for Practice
	Awareness, Choice, and Action. Awareness and Choice in Smart Cities Research. Insights emerging from this pa-
	per contribute to opportunities for further development of contemporary urban theory
	and to a discourse space related to awareness and smart cities.