Journal articles on the topic 'Nomadic computing'

New technologies and the deployment of mobile and nomadic services are driving the emergence of complex communications networks, that have a highly dynamic behavior. This naturally engenders new route-discovery problems under changing conditions over these networks. Unfortunately, the temporal variations in the network topology are hard to be effectively captured in a classical graph model. In this paper, we use and extend a recently proposed graph theoretic model, which helps capture the evolving characteristic of such networks, in order to propose and formally analyze least cost journey (the analog of paths in usual graphs) in a class of dynamic networks, where the changes in the topology can be predicted in advance. Cost measures investigated here are hop count (shortest journeys), arrival date (foremost journeys), and time span (fastest journeys).

IoT devices provide with real-time data to a rich ecosystems of services and applications that will be of uttermost importance for ubiquitous computing. The volume of data and the involved subscribe/notify signaling will likely become a challenge also for access and core netkworks. Designers may opt for microservice architectures and fog computing to address this challenge while offering the required flexibility for the main players of ubiquitous computing: nomadic users. Microservices require strong security support for Fog computing, to rely on nodes in the boundary of the network for secure data collection and processing. IoT low cost devices face outdated certificates and security support, due to the elapsed time from manufacture to deployment. In this paper we propose a solution based on microservice architectures and DNSSEC, DANE and chameleon signatures to overcome these difficulties. We will show how trap doors included in the certificates allow a secure and flexible delegation for off-loading data collection and processing to the fog. The main result is showing this requires minimal manufacture device configuration, thanks to DNSSEC support.

Mobile ad hoc networks (MANETs) are a collection of mobile nodes with a dynamic topology. MANETs work under scalable conditions for many applications and pose different security challenges. Due to the nomadic nature of nodes, detecting misbehaviour is a complex problem. Nodes also share routing information among the neighbours in order to find the route to the destination. This requires nodes to trust each other. Thus we can state that trust is a key concept in secure routing mechanisms. A number of cryptographic protection techniques based on trust have been proposed.Q-learning is a recently used technique, to achieve adaptive trust in MANETs. In comparison to other machine learning computational intelligence techniques,Q-learning achieves optimal results. Our work focuses on computing a score usingQ-learning to weigh the trust of a particular node over associativity based routing (ABR) protocol. Thus secure and stable route is calculated as a weighted average of the trust value of the nodes in the route and associativity ticks ensure the stability of the route. Simulation results show thatQ-learning based trust ABR protocol improves packet delivery ratio by 27% and reduces the route selection time by 40% over ABR protocol without trust calculation.

Advances in mobile computing and wireless communication are easing the evolution from traditional nomadic work to computer-mediated mobile collaborative work. Technology allows efficient and effective interaction among mobile users and also provides access to shared resources available to them. However, the features and capabilities of the communication infrastructure supporting these activities influence the type of coordination and collaboration employed by mobile collaborative applications in real work scenarios. Developers of these applications are typically unaware of the constraints the communication infrastructure imposes on mobile collaborative systems, because they are not easy to foresee. That leads to a high probability of communication problems in otherwise fully functional mobile collaborative support applications. This paper presents an experimental study with real devices and networks on a realistic physical environment that shows how ad hoc networks can effectively support mobile collaborative work and the practical limitations. The paper analyzes several networking issues and determines how they influence mobile collaborative work in various interaction scenarios. The paper also presents the lessons learned in the study and provides recommendations to deal with some networking issues related to real-world ad hoc networks.

Straipsnyje analizuojamos internetines paslaugas teikiančios sistemos, turinčios skirtingą architektūrą, akcentuojant prekių ir paslaugų reklamavimo ir radimo mechanizmus, įvertinami jų pranašumai ir trūkumai mažų ir vidutinių Lietuvos įmonių, norinčių pradėti teikti tokias paslaugas, požiūriu. Šiuo aspektu išnagrinėti paslaugų paieškos portalai ir pirkimų robotai, paslaugų paieška sistemose, veikiančiose atvirose išskirstytose aplinkose (SLP protokolas, CORBA, Jini technologija), paslaugųpaieškos internete technologijos (UDDI, DNS, X.500, Ninja, P2P internetinės failų apsikeitimo technologijos), saityno paslaugų ir lokalizuotų paslaugų paieškos technologijos, pateiktas kiekvienos ekspertinis vertinimas balais pagal adekvatumo, universalumo, paprastumo, brandos, sąnaudų ir kitus kriterijus.Evaluation of Suitability of Internet Service searchTechnologies for E-CommerceAlbertas Čaplinskas, Audronė Lupeikienė, Laima Paliulionienė SummaryThe paper analyzes Internet service systems of different architecture, paying special attention to the mechanisms of advertizing and finding services. Their pros and cons are discussed in the context of small and medium enterprises (SME) that want to use the technology for e-commerce in Lithuania. The paper overviews the technologies of online shops, shopbots, service search in open distributed processing (SLP protocol, CORBA, Jini), search in the Internet (UDDI, DNS, X.500, Ninja, peer-to-peer file sharing services), web services, and nomadic computing. A quantitative expert evaluation of each technology is performed taking into account its adequacy for the task under consideration, universality, simplicity, maturity, cost and other criteria.ne-height: 18px;">

IoT devices provide real-time data to a rich ecosystem of services and applications. The volume of data and the involved subscribe/notify signaling will likely become a challenge also for access and core networks. To alleviate the core of the network, other technologies like fog computing can be used. On the security side, designers of IoT low-cost devices and applications often reuse old versions of development frameworks and software components that contain vulnerabilities. Many server applications today are designed using microservice architectures where components are easier to update. Thus, IoT can benefit from deploying microservices in the fog as it offers the required flexibility for the main players of ubiquitous computing: nomadic users. In such deployments, IoT devices need the dynamic instantiation of microservices. IoT microservices require certificates so they can be accessed securely. Thus, every microservice instance may require a newly-created domain name and a certificate. The DNS-based Authentication of Named Entities (DANE) extension to Domain Name System Security Extensions (DNSSEC) allows linking a certificate to a given domain name. Thus, the combination of DNSSEC and DANE provides microservices’ clients with secure information regarding the domain name, IP address, and server certificate of a given microservice. However, IoT microservices may be short-lived since devices can move from one local fog to another, forcing DNSSEC servers to sign zones whenever new changes occur. Considering DNSSEC and DANE were designed to cope with static services, coping with IoT dynamic microservice instantiation can throttle the scalability in the fog. To overcome this limitation, this article proposes a solution that modifies the DNSSEC/DANE signature mechanism using chameleon signatures and defining a new soft delegation scheme. Chameleon signatures are signatures computed over a chameleon hash, which have a property: a secret trapdoor function can be used to compute collisions to the hash. Since the hash is maintained, the signature does not have to be computed again. In the soft delegation schema, DNS servers obtain a trapdoor that allows performing changes in a constrained zone without affecting normal DNS operation. In this way, a server can receive this soft delegation and modify the DNS zone to cope with frequent changes such as microservice dynamic instantiation. Changes in the soft delegated zone are much faster and do not require the intervention of the DNS primary servers of the zone.

Today the human being assumes a nomadic position in a ubiquitous society. It inhabits at the same time hyperspaces, characterized by the fluidity of communication mediated by emerging technologies of fast connection to the wireless networks, which contribute to interaction between people from both town and the small and little known village, even in the condition of displacement and ubiquity. The communicational ecologies in fluid spaces in hypermobility are a relevant aspect for the pedagogical use of Digital Information and Communication Technologies (DICT) in Distance Education (DE) since pedagogical actors, although geographically dispersed, can interact with each other. This study focuses mainly on the mapping and description of the pedagogical use of DICTs by the specialized tutors of the courses taught at EaD at the Pedagogical University of Mozambique - Delegation of Niassa (UPNI). For the empirical research, a survey was consciously and voluntarily answered by 30 tutors, 13 of which were from the AMA-Administration and Management Education, 11 from the BE-Basic Education course and 6 from the ET-English Teaching course. Among the participants in the survey half (50%) have between 31 to 40 years old. The results indicate high levels of satisfaction in terms of overcoming digital primary division rates and digital divide characterized by the possession by the subjects of the main computing devices and telecommunications with Internet access, access whose frequency ranges from weekly to daily. Considerable digital literacy was also observed in the use of digital technologies connected to the web through the exploration of software and web services by the participants, indicators evaluated as relevant for the pedagogical use of DICT in courses offered in the modality of Distance Education and more correlated to the cyberculture's time.

The Weather Research and Forecasting model (WRF) is an atmospheric simulation system designed for both research and operational applications. This worldwide used model requires a sophisticated modeling experience and computing skills. In this study, WRF model was used to predict many atmospheric parameters based on the initial conditions extracted from NOMADS data sets. The study area is basically the region surrounded by the longitudes and latitudes: 15o-75o E and 10.5o-45o N which typically includes the Middle East region. The model was installed on Linux platform with a grid size of 10 km in the X and Y directions. A low pressure trough was tracked in its movement from west to east via the Middle East during the period from 1 to 7 January 2010 as a case study of the WRF model. MATLAB and NCAR Command Language (NCL) were used to display the model output. To evaluate the forecasted parameters and patterns, some comparisons were made between the predicted and actual weather charts. Wind speeds and directions in the prognostic and actual charts of 700 hPa were in agreement. However, the predicted values of geopotential heights in WRF are somewhat overestimate the actual ones. This may be attributed to the differences in the data sources and data analysis methods of the two data agencies, NOMADS and ECMWF.

Ubiquitous Computing concept conceived by 'Mark Weiser' along with 'WEB 2.0' paradigm of present and ‘WEB Squared' of early future as described by 'Tim Oreille' [19,25] has made computing a common place occurrence which in twentieth century was considered a specialized job. Entire archetype of today's computing rests on growing technical strength of data processing and communicating techniques. Further, arrival of technical standards, which are essentialities for present Object Oriented Design (OOD) practices helped fast paced scientific advancement leading to nomadic and ubiquitous computing. Technology evolution around WEB 1.0 & 2.0 paradigms are follow ups of these developments. Abstraction and encapsulation of technical details in accordance with OOD allows usages of tricky devices without knowing complex intricacies. This has encouraged general participation in computing that changed face of social systems. As data processing and disseminating techniques are shifting from manual to digital form with agility and flexibility as constant value additions, digital social interactions leads to 'Social IT' concepts [1, 5, 17, 23].

Print culture, as the call for this issue suggests, has dominated the world for 500 years, but also suggests that print’s hegemony may now be under threat from new communications technologies. There are a number of perspectives from which to view the ‘threats’ to which print culture is subject, the longer term effects this will have and, particularly, on what it will mean to be human in the future of print culture. I’d like to address this issue by turning my attention to one dimension of this question that seems essentially absent from the discourses which surround it. I’d like to step back and put this question in the context of the structural relations of print as a cultural technology. My questions concern what these structural relations and their effects are, the limits of this print model of textuality, and what would constitute an ‘outside’ to the print system of texts. The point of this is to expose the ‘naturalised’ elements of this cultural formation, to show that there is as yet no radical break from print culture, and to consider the nature of the current pressures on print culture. The primary infrastructure of the print system concerns the structure of its texts, the structure of its modes of subject formation, and the structural relations between them. We should note how deeply embedded these structural relations are in terms of the idea of the human, of the idea of being human. Walter Ong (117-38), for example, has shown us how the print form is deeply embedded within culture and affects us at deeper levels than just the external manifestations of the medium. The conventions of print greatly influence and structure the ways in which it is possible to think – for Ong, the dominant communicational culture affects and determines the possibilities of thought and expression, and the relationships between individuals and texts structures the ways in which we view the world. This is what Ong calls “a psychological breakthrough of the first order”. For Ong, the achievement of alphabetic letterpress printing was that it “embedded the word itself deeply in the manufacturing process and made it a kind of commodity”. It was, he says, the first assembly line, and from this we have the mass distribution of texts, mass literacy through mass schooling, religion, etc. (Extended examinations of the function of religion in the construction of a print model can be pursued in both Aries and Luke.) Firstly, we must note that a model of textuality is not a natural thing; it is a technology. A textual model provides an infrastructure which determines and articulates the possibilities of relationships between those elements of the textual infrastructure – texts, subjects, and their relationships. As a consequence, the model also largely determines the possibilities for reading and writing within the textual system. The print-based system of texts has always presented an infrastructure that consists of a two-dimensional surface to which it sutures a subject in a face-to-face relationship – the requirement is for a certain kind of text, a certain kind of subject, and a certain kind of relationship between them in a highly prescribed and circumscribed textual infrastructure. This model of textuality is assumed as the natural mode of textuality, and consequently the referent for all textuality. What is obscured in the naturalisation of the print model of textuality are the technological dimensions of textuality: that all textual models are technologies. This print model has become so naturalised that it disappears. These structural relations of print do not change with the advent of the desktop personal computer, nor screen culture generally, as these are already cast within the infrastructure of the print model. Even three-dimensionality on the two-dimensional screen is always-already simulacra, constituted by continual changes on a surface which give only the appearance of three-dimensionality. The screen and keyboard therefore mark a continuity with the pre-existing social relations of print-based technology and its system of texts, and inscribe these textual relations in the model of the desktop personal computer. The essential “face-to-face” relation, where the subject is always placed “in front of”, also largely determines this subject. This mode of positionality is the condition of this subject. Its possibilities for “knowing” and “understanding”, if not wholly determined, are strongly influenced by this positionality. When Heidegger says that the meaning of the term understanding is intended to go back to its usage in ordinary language, he is referring to understanding (verstehen) in these terms: In German we say that someone can vorstehen something – literally stand in front or ahead of it, that is, stand at its head, administer, manage, preside over it. This is equivalent to saying that he versteht sich darauf, understands in the sense of being skilled or expert at it, has the know how of it. (Heidegger, “Age” 129-30) Such a subject, in that she or he is always placed “in front of” the text, surface, screen, page, is always the subject of the print age. This is the sense in which the desktop personal computer is still a Book. Accounts of computing per se initiating a radically new textuality, then, should proceed with caution. There is a new textual environment, to be sure, yet assertions of its radicality would seem firstly to refer to changes in degree rather than changes in kind. For Heidegger, the very essence of ‘man’ changes in the representationalist paradigm in that ‘man becomes subject’. He points out that the word sub-iectum names ‘that-which-lies-before’, and which ‘as ground, gathers everything onto itself’ (Heidegger, “Age” 128). When man becomes primary, then ‘man becomes that being upon which all that is is grounded as regards the manner of its Being and its truth’. It is only possible for man to become this relational centre when ‘the comprehension of what is as a whole changes’ (Heidegger, “Age” 128). In terms of this change, Heidegger says, we are asking after the ‘essence of the modern age’ which concerns the ‘modern world picture (Weltbild)’. World picture … does not mean a picture of the world but the world conceived and grasped as picture. … Whenever we have the world picture, an essential decision takes place regarding what is, in its entirety. The Being of whatever is, is sought and found in the representedness of the latter. He further points out that The world picture does not change from an earlier medieval one into a modern one, but rather the fact that the world becomes picture at all is what distinguishes the essence of the modern age. (Heidegger, “Age” 129-30) It is the positionality largely determined through these structural relations that enables the identity of the modernist subject, and the possibility of its representation (as an object for another subject). Representationalism therefore requires positionality in order to represent. The print subject is sutured to the page or screen and this always provides it with a representable position. The subject of representationalism therefore comes to appear as naturally given, just as, in this view, technology is also a given. Positionality concerns fixation, or what can be held to be true. Positionality is what Deleuze and Guattari oppose to nomadism which concerns constant movement and circulation. Representationalism requires this stable formation, and infusions of ‘noise’ into the system are rendered as pathologies. “Virtual reality” then, in that it disrupts or introduces something that is apparently new into the system, tends to become a pathologisation of the subject. It is on this basis that claims are made of crises in modes of subjectivity within virtual reality or cyberculture, where the problematic is mis-construed in terms of the subject rather than in terms of this model of interpretation. In this sense, it clings to the illusion of the subject as ground, that everything that is, is an object for a subject. In this model, it becomes a question of repositioning the subject such that the subject may be accommodated in an expanded representational regime, a practice that is widespread. Bukatman (8-9), for example, has argued a representationalist position which can be seen in the following passage. It is the purpose of much recent science fiction to construct a new subject position to interface with the global realms of data circulation, a subject that can occupy or intersect the cyberscapes of contemporary existence. For Bukatman, it is about a new position for the subject: that is, it is a question of how to represent the subject such that it can be accommodated to or within a representationalist paradigm. This subject is reduced to the notion of positionality which is representable as the subject labelled “I”. It concerns differences in degree rather than in kind. The establishing of the human subject as ground for “that which is” positions the human in an entirely different way from the subject of earlier times. For the first time, Heidegger says, there became such a thing as a “position” of the human. Humanity is subiectum, and must stand in front of, or “take his stand in relation to whatever is as the objective”. What is decisive, he says is that man himself expressly takes up this position as one constituted by himself, that he intentionally maintains it as that taken up by himself, and that he makes it secure as the solid footing for a possible development of humanity. (Heidegger, “Age” 132) This decisive event, for Heidegger, is what begins a new way of being human that gives rise to the world as picture. Heidegger’s “age of the world picture” corresponds with the arrival of the mass textual system or model (the printing press of the fifteenth century) which serves to instantiate this model of “man”. This is an actualisation of the technology of the subiectum, the age of the world picture, that is henceforth demanded in order to produce and to represent this “man”, and to represent him to himself. There has been no radical break with the structures underlying the social formation of print culture, yet this formation is subject to increasing pressures. What is most under pressure in this late age of print, however, is not the particular formation of texts, but, crucially, this mode of being human that has been ever more deeply embedded in the human psyche for more than 500 years. This will not disappear overnight; however, its structural conditions of existence do appear to be beginning to overflow their limit, producing an excess that is not, or not easily, assimilated back to itself. This excess is constituted by those contemporary elements that do not fit the structural model of the print system of texts. There are several aspects to this which can only be gestured towards in this space. In particular, one aspect will concern the complex network of relations in the changing nature of information in a digital, networked era, the commodification of information in global capitalism, and the distortions of space and time these produce. It gestures towards the possibility of a post-representationalism – a new subject that, rather than being fixed and positional, sutured to a screen/page, is set in motion – a structure which would alter all relations as well as the constitution of the subject. Immersive virtual reality texts already begin the necessity of thinking these relations and the possibility of a subject in motion within fields of information flow. These immersive virtual realities gesture towards the possibility of the subject becoming a post-print. A post-print will not emerge fully formed or all at once, or even very soon, but reflections on what such a system of texts and subjects might be or become poses the relations of print or our reflections on them in a different way. In any event, it points towards a difficult time ahead for the print subject and for the formation and meaning of print culture. References Aries, Philippe. Centuries of Childhood. Trans. Robert Baldick. London: Jonathan Cape, 1973. Bukatman, Scott. Terminal Identity: The Virtual Subject in Postmodern Science Fiction. Durham: Duke UP, 1993. Heidegger, Martin. The Basic Problems of Phenomenology. Trans. A. Hofstadter. Bloomington: Indiana UP, 1982. —. “The Age of the World Picture”. In Martin Heidegger, The Question Concerning Technology and Other Essays. Trans. William Lovitt. New York: Garland, 1977. 115-54. Luke, Carmen. Pedagogy, Printing, and Protestantism. Albany: State U of New York, 1989. Ong, Walter. Orality and Literacy: The Technologizing of the Word. London: Routledge. 1982. Citation reference for this article MLA Style Roe, Phillip. "Dimensions of Print." M/C Journal 8.2 (2005). echo date('d M. Y'); ?> <http://journal.media-culture.org.au/0506/07-roe.php>. APA Style Roe, P. (Jun. 2005) "Dimensions of Print," M/C Journal, 8(2). Retrieved echo date('d M. Y'); ?> from <http://journal.media-culture.org.au/0506/07-roe.php>.