Artículos de revistas sobre el tema "Broadband ambiguity function"

This paper considers methods for estimating the mutual time delay of broadband signals recorded by satellites based multi-position systems for determining the location of a radiation source. All methods considered are based on modified algorithms for calculating the ambiguity function. The presented algorithms are based on the extraction of narrowband channels from the studied signals and their further optimal processing. The reliability criterion for mutual time delay estimation by the presented methods was evaluated. Based on the results and analysis of computational efficiency, viability of methods considered and their modifications was determined.

The study analysed possible resolution of two ground-based MIMO microwave camera designs by means of two-dimensional spatial cross-sections of a generalized ambiguity function. We used stepped-frequency modulated broadband signals as time-orthogonal probing signals for the microwave camera transmitters. We employed a mathematical simulation of the space-time signal processing system pertaining to MIMO microwave camera receivers to illustrate 2D and 3D microwave imaging of stationary extended multipoint objects situated at various altitudes above the earth surface.

This paper studies resolution of matched field processing for locating, in range and depth, a broadband underwater acoustic source from data measured at a single hydrophone receiver. For the case of an ideal rigid shallow-water waveguide with a pressure-release top boundary and a rigid bottom boundary, we derive approximations for the main-lobe widths of the ambiguity surface. The two cases studied in this paper are (1) when coherent measurements of the pressure are available, with the transmitted source waveform precisely known, and (2) when only measurements of the received signal power spectral density (PSD) are available, such as occur when the transmitted signal is random and unknown. The analysis uses the normal-mode expansion for the pressure field to derive approximate expressions for the ambiguity surface main-lobe widths, as a function of the number of modes and frequency band, for both range and depth. Numerical results are presented corroborating the analytical analysis. Finally, we argue that this ambiguity analysis also gives insights into real ocean waveguide localization characteristics under appropriate conditions, and show numerical simulations of matched field localization ambiguity surfaces for some realistic shallow-water Pekeris environments.

This paper studies resolution of matched field processing for locating, in range and depth, a broadband underwater acoustic source from data measured at a single hydrophone receiver. For the case of an ideal rigid shallow-water waveguide with a pressure-release top boundary and a rigid bottom boundary, the paper derives approximations for the main-lobe widths of the ambiguity surface. The two cases studied in this paper are (1) when coherent measurements of the pressure are available, with the transmitted source waveform precisely known, and (2) when only measurements of the received-signal pressure magnitude-squared are available, such as might occur when the transmitted signal is random and unknown. The analysis uses the normal-mode expansion for the pressure field to derive approximate expressions for the ambiguity-surface main-lobe widths, as a function of the number of modes and frequency band, for both range and depth. Numerical results are presented corroborating the analytical analysis. Finally, the paper argues that this ambiguity analysis can also give insights into Pekeris waveguides under appropriate conditions and shows numerical simulations of matched-field localization ambiguity surfaces for some realistic shallow-water Pekeris environments.

Syntax, the combination of meaning-devoid phonemes into meaningful words, which in turn are combined in structurally and semantically complex sentences, is fundamental to the unlimited expressiveness of human languages. Studying the functions of call combinations in non-human species provides insights into the evolution of such syntactic capabilities. Here, we investigated the combination of high amplitude broadband calls with low frequency rumble vocalizations in a highly social species, the African forest elephant Loxodonta cyclotis. Rumbles play an integral role in coordinating social interactions by transmitting socially relevant information, including individual identity. By contrast, broadband calls, such as roars, are thought to function as signals of distress and urgency as they are typically produced in situations of high emotional intensity. Functional changes associated with the combination of these calls remain little understood. We found that call combinations were produced by all age-sex classes but were most prevalent in immature individuals. We found that rumbles used singularly occurred in all five investigated social contexts, whereas single broadband calls were restricted to two resource-related contexts. Call combinations also occurred in all five contexts, suggesting an increase in the functional use of broadband calls when combined with rumbles, analogous to the generativity brought about through syntax in human speech. Moreover, combining calls appeared to lead to functional shifts towards high-stake contexts. Call combinations were more likely in competition contexts compared to single rumbles, and more likely in separation contexts compared to single broadband calls. We suggest that call combination in forest elephants may aide to reduce message ambiguity in high-stake situation by simultaneously communicating distress and individual identity, which may be critical to secure access to resources, reduce the risk of injury and to reunite with or recruit the support of the family group.

Broadband acoustic Doppler current profiler (ADCP) is widely used in agricultural water resource explorations, such as river discharge monitoring and flood warning. Improving the velocity estimation accuracy of broadband ADCP by adjusting the waveform parameters of a phase-encoded signal will reduce the velocity measurement range and water stratification accuracy, while the promotion of stratification accuracy will degrade the velocity estimation accuracy. In order to minimize the impact of these two problems on the measurement results, the ADCP waveform optimization problem that satisfies the environment constraints while keeping high velocity estimation accuracy or stratification accuracy is studied. Firstly, the relationship between velocity or distance estimation accuracy and signal waveform parameters is studied by using an ambiguity function. Secondly, the constraints of current velocity range, velocity distribution and other environmental characteristics on the waveform parameters are studied. For two common measurement applications, two dynamic configuration methods of waveform parameters with environmental adaptability and optimal velocity estimation accuracy or stratification accuracy are proposed based on the nonlinear programming principle. Experimental results show that compared with the existing methods, the velocity estimation accuracy of the proposed method is improved by more than 50%, and the stratification accuracy is improved by more than 22%.

The Doppler effect is usually described as a frequency shift of the backscattered signals from moving targets with respect to the frequency transmitted. Recently, real-time blood flow imaging has become possible thanks to the development of a new velocity estimator based on phase-shift measurements of successive echoes. However, this method suffers from the well-known limitations of pulse-Doppler instruments. A new formulation is presented which describes the pulse-Doppler effect on the successive echoes from a cloud of moving targets as a progressive translation in time due to the displacement of the scatterers between two excitations. This approach allows us to generate efficiently computer-simulated data in order to evaluate accurately the various processing techniques. Furthermore, it leads to a novel class of velocity estimators in the time domain which measure the time shifts which are proportional to the local blood velocity. Among them, the cross correlation of the received rf signals turns out to be well suited. A local cross-correlation function is first calculated from a consecutive pair of range-gated echoes and the time shift is then determined by searching for the time position with the maximum correlation. The time-correlation technique is shown to provide accurate velocity profiles with broadband transducers. Moreover, the classical velocity limitation of pulse-Doppler is overcome because there is no ambiguity in measuring a time shift instead of a phase shift. These major advantages should make quantitative flow mapping possible and more reliable.

The Ukrainian VLBI system of decameter radio telescopes URAN successfully solves many scientific problems, but implementing aperture synthesis technology has a number of difficulties. One of them is significant phase distortions in this range caused by an inhomogeneous propagation environment. Therefore, the task arose to develop an alternative technology with the conventional name "Interferovision", which would allow us to restore radio images with a limited number of antennas, operate with broadband signals, not require flatness of the objects scene, and have an extended field of view. A method of direct image reconstruction when observing objects in space, using a multi-element interferometer, is proposed. This method is based on a physically based principle that is similar to holography. The wave front is registered by the antennas of the interferometer, and further processing is equivalent to its playback in reverse and registration of the resulting spatial interference image. There are no special requirements for the radiation of individual points of the source, except for its delta correlation. A finite frequency band is considered, and each point can be characterized by its own spectrum, that is, its own autocorrelation function of radiation. The resolution of the direct reconstruction method depends on its width. With the quasi-monochromatic approximation, the autocorrelation functions of the radiation of all the source points degenerate into sinusoids, and the restoration of the image becomes possible only with the use of the Fourier transformation. A theoretical justification of the method for spaces of different dimensions has been obtained. Interferometric systems of the same rank with many antennas are reduced to a same canonical form with fixed number of virtual antennas placed at the origin of the coordinates and at unit distances on the coordinate axes. The ambiguity of the obtained solution is eliminated by using an additional antenna. A simulation of the proposed method of direct image reconstruction for two-dimensional space was carried out. Despite the low conditionality of the system for estimating the distance, when it increases, the angular characteristics are preserved. Therefore, the method is promising for restoring radio images of space radio sources.

Full waveform inversion (FWI) aims at a broadband reconstruction of the subsurface physical properties by fitting the entire recorded wavefield. In realistic exploration seismic surveys, however, conventional FWI often fails to retrieve the deep velocity model due to the limited penetration depth of diving waves. Joint FWI (JFWI) unifies reflection-waveform inversion (RWI) and early-arrival waveform inversion (EWI) to reconstruct simutaneously the shallow and deep subsurface kinematics. However, a number of factors limit the appeal of JFWI velocity-model-building: 1) conflict between fixed reflectivity and evolving kinematics, creating phase ambiguity at short offsets; 2) susceptibility to cycle skipping at mid-to-long offsets, thus reliance on the quality of the starting model; 3) cost of building and updating the reflective model. We present a fully operational JFWI-based methodology that systematically addresses the aforementioned issues. JFWI is re-formulated in the pseudotime domain, in order to enforce consistency between velocity and reflectivity in a cost-effective fashion, without repeated least-square migrations. A JFWI graph space optimal transport (GSOT) objective function is designed to avert cycle skipping, while non-uniqueness is mitigated at no extra cost by smoothing the velocity gradient along the structures extracted from the reflective model. A dedicated asymptotic-based preconditioner is developed for impedance waveform inversion, making it possible to obtain sharp and balanced reflective images in a fraction of the time. We demonstrate that Pseudotime GSOT-JFWI retrieves complex velocity macromodels from limited-offset datasets with minimal pre-processing, starting from non-informative initial solutions. Compared to depth-domain JFWI, the computing cost is reduced significantly, along with a simpler and less subjective design of data weighting and inversion strategy. Pseudotime GSOT-JFWI provides FWI with the necessary low-wavenumbers to converge to the broadband model, reducing the need for accurate starting models, on the road to a fully waveform-based imaging workflow.

AbstractThe Banda arc‐continent collision zone signifies one of the most seismically active and tectonically intricate zones. The high convergence rate across the region, coupled with the exceptionally arcuate arc and subducted slab, makes it an ideal locale for investigating interactions between plate (slab) kinematics and plastic flow in the asthenosphere, which can be diagnosed by seismic anisotropy from shear wave splitting analyses. In total, 206 pairs of splitting measurements using teleseismic SKS, SKKS, and PKS, along with 43 pairs using local S phases, are obtained by utilizing broadband seismic data from five permanent seismic stations. To reduce the ambiguity in determining the origin of anisotropy leading to the teleseismic splittings, which lack vertical resolution, crustal anisotropy is constrained according to the sinusoidal moveout of converted S phases at the Moho using receiver functions. A layered anisotropic structure based on joint analyses of the anisotropy measurements characterizing different depth layers suggests the presence of trench‐parallel flow both in the mantle wedge and the sub‐slab region. The northeastward motion of the slab, entrained by the fast‐moving Australian Plate, deflects asthenospheric materials. The modulation results in trench‐parallel plastic mantle flows and leads to the steepening of the southern portion of the asymmetric spoon‐shaped Banda slab. In the shallower part of the sub‐slab region, the northeastward Australian Plate motion produces simple shear in the transitional layer between the rigid lithosphere and the viscous asthenosphere. The shear deformation induces seismic anisotropy with resulting fast orientations in accordance with the plate motion direction.

There is no diagram that does not also include, besides the points it connects up, certain relatively free or unbounded points, points of creativity, change and resistance, and it is perhaps with these that we ought to begin in order to understand the whole picture. (Deleuze, “Foucault” 37) Monty Cantsin: Why do we use a pervert software robot to exploit our collective consensual mind? Letitia: Because we want the thief to be a digital entity. Monty Cantsin: But isn’t this really blasphemic? Letitia: Yes, but god – in our case a meta-cocktail of authorship and copyright – can not be trusted anymore. (Amazon Noir, “Dialogue”) In 2006, some 3,000 digital copies of books were silently “stolen” from online retailer Amazon.com by targeting vulnerabilities in the “Search inside the Book” feature from the company’s website. Over several weeks, between July and October, a specially designed software program bombarded the Search Inside!™ interface with multiple requests, assembling full versions of texts and distributing them across peer-to-peer networks (P2P). Rather than a purely malicious and anonymous hack, however, the “heist” was publicised as a tactical media performance, Amazon Noir, produced by self-proclaimed super-villains Paolo Cirio, Alessandro Ludovico, and Ubermorgen.com. While controversially directed at highlighting the infrastructures that materially enforce property rights and access to knowledge online, the exploit additionally interrogated its own interventionist status as theoretically and politically ambiguous. That the “thief” was represented as a digital entity or machinic process (operating on the very terrain where exchange is differentiated) and the emergent act of “piracy” was fictionalised through the genre of noir conveys something of the indeterminacy or immensurability of the event. In this short article, I discuss some political aspects of intellectual property in relation to the complexities of Amazon Noir, particularly in the context of control, technological action, and discourses of freedom. Software, Piracy As a force of distribution, the Internet is continually subject to controversies concerning flows and permutations of agency. While often directed by discourses cast in terms of either radical autonomy or control, the technical constitution of these digital systems is more regularly a case of establishing structures of operation, codified rules, or conditions of possibility; that is, of guiding social processes and relations (McKenzie, “Cutting Code” 1-19). Software, as a medium through which such communication unfolds and becomes organised, is difficult to conceptualise as a result of being so event-orientated. There lies a complicated logic of contingency and calculation at its centre, a dimension exacerbated by the global scale of informational networks, where the inability to comprehend an environment that exceeds the limits of individual experience is frequently expressed through desires, anxieties, paranoia. Unsurprisingly, cautionary accounts and moral panics on identity theft, email fraud, pornography, surveillance, hackers, and computer viruses are as commonplace as those narratives advocating user interactivity. When analysing digital systems, cultural theory often struggles to describe forces that dictate movement and relations between disparate entities composed by code, an aspect heightened by the intensive movement of informational networks where differences are worked out through the constant exposure to unpredictability and chance (Terranova, “Communication beyond Meaning”). Such volatility partially explains the recent turn to distribution in media theory, as once durable networks for constructing economic difference – organising information in space and time (“at a distance”), accelerating or delaying its delivery – appear contingent, unstable, or consistently irregular (Cubitt 194). Attributing actions to users, programmers, or the software itself is a difficult task when faced with these states of co-emergence, especially in the context of sharing knowledge and distributing media content. Exchanges between corporate entities, mainstream media, popular cultural producers, and legal institutions over P2P networks represent an ongoing controversy in this respect, with numerous stakeholders competing between investments in property, innovation, piracy, and publics. Beginning to understand this problematic landscape is an urgent task, especially in relation to the technological dynamics that organised and propel such antagonisms. In the influential fragment, “Postscript on the Societies of Control,” Gilles Deleuze describes the historical passage from modern forms of organised enclosure (the prison, clinic, factory) to the contemporary arrangement of relational apparatuses and open systems as being materially provoked by – but not limited to – the mass deployment of networked digital technologies. In his analysis, the disciplinary mode most famously described by Foucault is spatially extended to informational systems based on code and flexibility. According to Deleuze, these cybernetic machines are connected into apparatuses that aim for intrusive monitoring: “in a control-based system nothing’s left alone for long” (“Control and Becoming” 175). Such a constant networking of behaviour is described as a shift from “molds” to “modulation,” where controls become “a self-transmuting molding changing from one moment to the next, or like a sieve whose mesh varies from one point to another” (“Postscript” 179). Accordingly, the crisis underpinning civil institutions is consistent with the generalisation of disciplinary logics across social space, forming an intensive modulation of everyday life, but one ambiguously associated with socio-technical ensembles. The precise dynamics of this epistemic shift are significant in terms of political agency: while control implies an arrangement capable of absorbing massive contingency, a series of complex instabilities actually mark its operation. Noise, viral contamination, and piracy are identified as key points of discontinuity; they appear as divisions or “errors” that force change by promoting indeterminacies in a system that would otherwise appear infinitely calculable, programmable, and predictable. The rendering of piracy as a tactic of resistance, a technique capable of levelling out the uneven economic field of global capitalism, has become a predictable catch-cry for political activists. In their analysis of multitude, for instance, Antonio Negri and Michael Hardt describe the contradictions of post-Fordist production as conjuring forth a tendency for labour to “become common.” That is, as productivity depends on flexibility, communication, and cognitive skills, directed by the cultivation of an ideal entrepreneurial or flexible subject, the greater the possibilities for self-organised forms of living that significantly challenge its operation. In this case, intellectual property exemplifies such a spiralling paradoxical logic, since “the infinite reproducibility central to these immaterial forms of property directly undermines any such construction of scarcity” (Hardt and Negri 180). The implications of the filesharing program Napster, accordingly, are read as not merely directed toward theft, but in relation to the private character of the property itself; a kind of social piracy is perpetuated that is viewed as radically recomposing social resources and relations. Ravi Sundaram, a co-founder of the Sarai new media initiative in Delhi, has meanwhile drawn attention to the existence of “pirate modernities” capable of being actualised when individuals or local groups gain illegitimate access to distributive media technologies; these are worlds of “innovation and non-legality,” of electronic survival strategies that partake in cultures of dispersal and escape simple classification (94). Meanwhile, pirate entrepreneurs Magnus Eriksson and Rasmus Fleische – associated with the notorious Piratbyrn – have promoted the bleeding away of Hollywood profits through fully deployed P2P networks, with the intention of pushing filesharing dynamics to an extreme in order to radicalise the potential for social change (“Copies and Context”). From an aesthetic perspective, such activist theories are complemented by the affective register of appropriation art, a movement broadly conceived in terms of antagonistically liberating knowledge from the confines of intellectual property: “those who pirate and hijack owned material, attempting to free information, art, film, and music – the rhetoric of our cultural life – from what they see as the prison of private ownership” (Harold 114). These “unruly” escape attempts are pursued through various modes of engagement, from experimental performances with legislative infrastructures (i.e. Kembrew McLeod’s patenting of the phrase “freedom of expression”) to musical remix projects, such as the work of Negativland, John Oswald, RTMark, Detritus, Illegal Art, and the Evolution Control Committee. Amazon Noir, while similarly engaging with questions of ownership, is distinguished by specifically targeting information communication systems and finding “niches” or gaps between overlapping networks of control and economic governance. Hans Bernhard and Lizvlx from Ubermorgen.com (meaning ‘Day after Tomorrow,’ or ‘Super-Tomorrow’) actually describe their work as “research-based”: “we not are opportunistic, money-driven or success-driven, our central motivation is to gain as much information as possible as fast as possible as chaotic as possible and to redistribute this information via digital channels” (“Interview with Ubermorgen”). This has led to experiments like Google Will Eat Itself (2005) and the construction of the automated software thief against Amazon.com, as process-based explorations of technological action. Agency, Distribution Deleuze’s “postscript” on control has proven massively influential for new media art by introducing a series of key questions on power (or desire) and digital networks. As a social diagram, however, control should be understood as a partial rather than totalising map of relations, referring to the augmentation of disciplinary power in specific technological settings. While control is a conceptual regime that refers to open-ended terrains beyond the architectural locales of enclosure, implying a move toward informational networks, data solicitation, and cybernetic feedback, there remains a peculiar contingent dimension to its limits. For example, software code is typically designed to remain cycling until user input is provided. There is a specifically immanent and localised quality to its actions that might be taken as exemplary of control as a continuously modulating affective materialism. The outcome is a heightened sense of bounded emergencies that are either flattened out or absorbed through reconstitution; however, these are never linear gestures of containment. As Tiziana Terranova observes, control operates through multilayered mechanisms of order and organisation: “messy local assemblages and compositions, subjective and machinic, characterised by different types of psychic investments, that cannot be the subject of normative, pre-made political judgments, but which need to be thought anew again and again, each time, in specific dynamic compositions” (“Of Sense and Sensibility” 34). This event-orientated vitality accounts for the political ambitions of tactical media as opening out communication channels through selective “transversal” targeting. Amazon Noir, for that reason, is pitched specifically against the material processes of communication. The system used to harvest the content from “Search inside the Book” is described as “robot-perversion-technology,” based on a network of four servers around the globe, each with a specific function: one located in the United States that retrieved (or “sucked”) the books from the site, one in Russia that injected the assembled documents onto P2P networks and two in Europe that coordinated the action via intelligent automated programs (see “The Diagram”). According to the “villains,” the main goal was to steal all 150,000 books from Search Inside!™ then use the same technology to steal books from the “Google Print Service” (the exploit was limited only by the amount of technological resources financially available, but there are apparent plans to improve the technique by reinvesting the money received through the settlement with Amazon.com not to publicise the hack). In terms of informational culture, this system resembles a machinic process directed at redistributing copyright content; “The Diagram” visualises key processes that define digital piracy as an emergent phenomenon within an open-ended and responsive milieu. That is, the static image foregrounds something of the activity of copying being a technological action that complicates any analysis focusing purely on copyright as content. In this respect, intellectual property rights are revealed as being entangled within information architectures as communication management and cultural recombination – dissipated and enforced by a measured interplay between openness and obstruction, resonance and emergence (Terranova, “Communication beyond Meaning” 52). To understand data distribution requires an acknowledgement of these underlying nonhuman relations that allow for such informational exchanges. It requires an understanding of the permutations of agency carried along by digital entities. According to Lawrence Lessig’s influential argument, code is not merely an object of governance, but has an overt legislative function itself. Within the informational environments of software, “a law is defined, not through a statue, but through the code that governs the space” (20). These points of symmetry are understood as concretised social values: they are material standards that regulate flow. Similarly, Alexander Galloway describes computer protocols as non-institutional “etiquette for autonomous agents,” or “conventional rules that govern the set of possible behavior patterns within a heterogeneous system” (7). In his analysis, these agreed-upon standardised actions operate as a style of management fostered by contradiction: progressive though reactionary, encouraging diversity by striving for the universal, synonymous with possibility but completely predetermined, and so on (243-244). Needless to say, political uncertainties arise from a paradigm that generates internal material obscurities through a constant twinning of freedom and control. For Wendy Hui Kyong Chun, these Cold War systems subvert the possibilities for any actual experience of autonomy by generalising paranoia through constant intrusion and reducing social problems to questions of technological optimisation (1-30). In confrontation with these seemingly ubiquitous regulatory structures, cultural theory requires a critical vocabulary differentiated from computer engineering to account for the sociality that permeates through and concatenates technological realities. In his recent work on “mundane” devices, software and code, Adrian McKenzie introduces a relevant analytic approach in the concept of technological action as something that both abstracts and concretises relations in a diffusion of collective-individual forces. Drawing on the thought of French philosopher Gilbert Simondon, he uses the term “transduction” to identify a key characteristic of technology in the relational process of becoming, or ontogenesis. This is described as bringing together disparate things into composites of relations that evolve and propagate a structure throughout a domain, or “overflow existing modalities of perception and movement on many scales” (“Impersonal and Personal Forces in Technological Action” 201). Most importantly, these innovative diffusions or contagions occur by bridging states of difference or incompatibilities. Technological action, therefore, arises from a particular type of disjunctive relation between an entity and something external to itself: “in making this relation, technical action changes not only the ensemble, but also the form of life of its agent. Abstraction comes into being and begins to subsume or reconfigure existing relations between the inside and outside” (203). Here, reciprocal interactions between two states or dimensions actualise disparate potentials through metastability: an equilibrium that proliferates, unfolds, and drives individuation. While drawing on cybernetics and dealing with specific technological platforms, McKenzie’s work can be extended to describe the significance of informational devices throughout control societies as a whole, particularly as a predictive and future-orientated force that thrives on staged conflicts. Moreover, being a non-deterministic technical theory, it additionally speaks to new tendencies in regimes of production that harness cognition and cooperation through specially designed infrastructures to enact persistent innovation without any end-point, final goal or natural target (Thrift 283-295). Here, the interface between intellectual property and reproduction can be seen as a site of variation that weaves together disparate objects and entities by imbrication in social life itself. These are specific acts of interference that propel relations toward unforeseen conclusions by drawing on memories, attention spans, material-technical traits, and so on. The focus lies on performance, context, and design “as a continual process of tuning arrived at by distributed aspiration” (Thrift 295). This later point is demonstrated in recent scholarly treatments of filesharing networks as media ecologies. Kate Crawford, for instance, describes the movement of P2P as processual or adaptive, comparable to technological action, marked by key transitions from partially decentralised architectures such as Napster, to the fully distributed systems of Gnutella and seeded swarm-based networks like BitTorrent (30-39). Each of these technologies can be understood as a response to various legal incursions, producing radically dissimilar socio-technological dynamics and emergent trends for how agency is modulated by informational exchanges. Indeed, even these aberrant formations are characterised by modes of commodification that continually spillover and feedback on themselves, repositioning markets and commodities in doing so, from MP3s to iPods, P2P to broadband subscription rates. However, one key limitation of this ontological approach is apparent when dealing with the sheer scale of activity involved, where mass participation elicits certain degrees of obscurity and relative safety in numbers. This represents an obvious problem for analysis, as dynamics can easily be identified in the broadest conceptual sense, without any understanding of the specific contexts of usage, political impacts, and economic effects for participants in their everyday consumptive habits. Large-scale distributed ensembles are “problematic” in their technological constitution, as a result. They are sites of expansive overflow that provoke an equivalent individuation of thought, as the Recording Industry Association of America observes on their educational website: “because of the nature of the theft, the damage is not always easy to calculate but not hard to envision” (“Piracy”). The politics of the filesharing debate, in this sense, depends on the command of imaginaries; that is, being able to conceptualise an overarching structural consistency to a persistent and adaptive ecology. As a mode of tactical intervention, Amazon Noir dramatises these ambiguities by framing technological action through the fictional sensibilities of narrative genre. Ambiguity, Control The extensive use of imagery and iconography from “noir” can be understood as an explicit reference to the increasing criminalisation of copyright violation through digital technologies. However, the term also refers to the indistinct or uncertain effects produced by this tactical intervention: who are the “bad guys” or the “good guys”? Are positions like ‘good’ and ‘evil’ (something like freedom or tyranny) so easily identified and distinguished? As Paolo Cirio explains, this political disposition is deliberately kept obscure in the project: “it’s a representation of the actual ambiguity about copyright issues, where every case seems to lack a moral or ethical basis” (“Amazon Noir Interview”). While user communications made available on the site clearly identify culprits (describing the project as jeopardising arts funding, as both irresponsible and arrogant), the self-description of the artists as political “failures” highlights the uncertainty regarding the project’s qualities as a force of long-term social renewal: Lizvlx from Ubermorgen.com had daily shootouts with the global mass-media, Cirio continuously pushed the boundaries of copyright (books are just pixels on a screen or just ink on paper), Ludovico and Bernhard resisted kickback-bribes from powerful Amazon.com until they finally gave in and sold the technology for an undisclosed sum to Amazon. Betrayal, blasphemy and pessimism finally split the gang of bad guys. (“Press Release”) Here, the adaptive and flexible qualities of informatic commodities and computational systems of distribution are knowingly posited as critical limits; in a certain sense, the project fails technologically in order to succeed conceptually. From a cynical perspective, this might be interpreted as guaranteeing authenticity by insisting on the useless or non-instrumental quality of art. However, through this process, Amazon Noir illustrates how forces confined as exterior to control (virality, piracy, noncommunication) regularly operate as points of distinction to generate change and innovation. Just as hackers are legitimately employed to challenge the durability of network exchanges, malfunctions are relied upon as potential sources of future information. Indeed, the notion of demonstrating ‘autonomy’ by illustrating the shortcomings of software is entirely consistent with the logic of control as a modulating organisational diagram. These so-called “circuit breakers” are positioned as points of bifurcation that open up new systems and encompass a more general “abstract machine” or tendency governing contemporary capitalism (Parikka 300). As a consequence, the ambiguities of Amazon Noir emerge not just from the contrary articulation of intellectual property and digital technology, but additionally through the concept of thinking “resistance” simultaneously with regimes of control. This tension is apparent in Galloway’s analysis of the cybernetic machines that are synonymous with the operation of Deleuzian control societies – i.e. “computerised information management” – where tactical media are posited as potential modes of contestation against the tyranny of code, “able to exploit flaws in protocological and proprietary command and control, not to destroy technology, but to sculpt protocol and make it better suited to people’s real desires” (176). While pushing a system into a state of hypertrophy to reform digital architectures might represent a possible technique that produces a space through which to imagine something like “our” freedom, it still leaves unexamined the desire for reformation itself as nurtured by and produced through the coupling of cybernetics, information theory, and distributed networking. This draws into focus the significance of McKenzie’s Simondon-inspired cybernetic perspective on socio-technological ensembles as being always-already predetermined by and driven through asymmetries or difference. As Chun observes, consequently, there is no paradox between resistance and capture since “control and freedom are not opposites, but different sides of the same coin: just as discipline served as a grid on which liberty was established, control is the matrix that enables freedom as openness” (71). Why “openness” should be so readily equated with a state of being free represents a major unexamined presumption of digital culture, and leads to the associated predicament of attempting to think of how this freedom has become something one cannot not desire. If Amazon Noir has political currency in this context, however, it emerges from a capacity to recognise how informational networks channel desire, memories, and imaginative visions rather than just cultivated antagonisms and counterintuitive economics. As a final point, it is worth observing that the project was initiated without publicity until the settlement with Amazon.com. There is, as a consequence, nothing to suggest that this subversive “event” might have actually occurred, a feeling heightened by the abstractions of software entities. To the extent that we believe in “the big book heist,” that such an act is even possible, is a gauge through which the paranoia of control societies is illuminated as a longing or desire for autonomy. As Hakim Bey observes in his conceptualisation of “pirate utopias,” such fleeting encounters with the imaginaries of freedom flow back into the experience of the everyday as political instantiations of utopian hope. Amazon Noir, with all its underlying ethical ambiguities, presents us with a challenge to rethink these affective investments by considering our profound weaknesses to master the complexities and constant intrusions of control. It provides an opportunity to conceive of a future that begins with limits and limitations as immanently central, even foundational, to our deep interconnection with socio-technological ensembles. References “Amazon Noir – The Big Book Crime.” http://www.amazon-noir.com/>. Bey, Hakim. 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