Streaming analysis in wireless sensor networks

Two new incremental models for online anomaly detection in data streams at nodes in wireless sensor networks are discussed. These models are incremental versions of a model that uses ellipsoids to detect first, second, and higher-ordered anomalies in arrears. The incremental versions can also be used this way but have additional capabilities offered by processing data incrementally as they arrive in time. Specifically, they can detect anomalies 'on-the-fly' in near real time. They can also be used to track temporal changes in near real-time because of sensor drift, cyclic variation, or seasonal changes. One of the new models has a mechanism that enables graceful degradation of inputs in the distant past (fading memory). Three real datasets from single sensors in deployed environmental monitoring networks are used to illustrate various facets of the new models. Examples compare the incremental version with the previous batch and dynamic models and show that the incremental versions can detect various types of dynamic anomalies in near real time.

Australia : webcasting : "pretty dead, really" - or is it?

Webcasting, sometimes labeled the "last frontier" or "the next stage of evolution" of the internet era, has been slow in its diffusion in Australia, due to technical constraints related to internet transmission speeds and bandwidth (Morrissey, 2003, cited in Lin, 2004, p. 446). According to Craig Preston, Operations Coordinator for New Media and Digital Services at the Australian Broadcasting Corporation (or ABC, a national broadcaster), webcasting in Australia is "pretty dead, really" (c. Preston, personal communication, August 23, 2005). This statement will be examined in this chapter, especially since the Australian Media Guide does not list "web casting" or "streaming" as a category or include the terms among its long list of entries (Gee, 2005)

Discovering frequent sets from data streams with CPU constraint

Data streams are usually generated in an online fashion characterized by huge volume, rapid unpredictable rates, and fast changing data characteristics. It has been hence recognized that mining over streaming data requires the problem of limited computational resources to be adequately addressed. Since the arrival rate of data streams can significantly increase and exceed the CPU capacity, the machinery must adapt to this change to guarantee the timeliness of the results. We present an online algorithm to approximate a set of frequent patterns from a sliding window over the underlying data stream - given apriori CPU capacity. The algorithm automatically detects overload situations and can adaptively shed unprocessed data to guarantee the timely results. We theoretically prove, using probabilistic and deterministic techniques, that the error on the output results is bounded within a pre-specified threshold. The empirical results on various datasets also confirmed the feasiblity of our proposal.

Online mining of frequent sets in data streams with error guarantee

For most data stream applications, the volume of data is too huge to be stored in permanent devices or to be thoroughly scanned more than once. It is hence recognized that approximate answers are usually sufficient, where a good approximation obtained in a timely manner is often better than the exact answer that is delayed beyond the window of opportunity. Unfortunately, this is not the case for mining frequent patterns over data streams where algorithms capable of online processing data streams do not conform strictly to a precise error guarantee. Since the quality of approximate answers is as important as their timely delivery, it is necessary to design algorithms to meet both criteria at the same time. In this paper, we propose an algorithm that allows online processing of streaming data and yet guaranteeing the support error of frequent patterns strictly within a user-specified threshold. Our theoretical and experimental studies show that our algorithm is an effective and reliable method for finding frequent sets in data stream environments when both constraints need to be satisfied.

Potential uses of ultrasound in the dairy ultrafiltration processes

There has been a growing interest in the industrial application of ultrasound, especially in the food industry. Power ultrasound can have a number of physical effects; it can increase turbulence through both the introduction of vibrational energy and through acoustic streaming, it can cause both particle agglomeration and particle dispersion and clean surfaces with a scouring action. Our work in this area has focused on the use of ultrasound to enhance membrane processing. Low frequency ultrasound has been used to facilitate cross flow ultrafiltration of dairy whey solutions for both during the ultrafiltration production cycle and the cleaning cycle. During the production cycle, the use of ultrasound reduces both pore blockage and the specific resistance of the fouling cake layer. This leads to higher flux rates and the potential for longer production cycles. During the cleaning cycle, ultrasound systematically increases cleaning efficiency, thus has the potential to reduce both total chemical consumption and system downtime. There was no deterioration in cleaning effectiveness or membrane condition which imples that sonication , has not damaged the membrane itself. Similarly, there was no change in the chemical nature of soluble proteins following sonication.

Cellular adaption to repeated eccentric exercise-induced muscle damage

Eccentrically biased exercise results in skeletal muscle damage and stimulates adaptations in muscle, whereby indexes of damage are attenuated when the exercise is repeated. We hypothesized that changes in ultrastructural damage, inflammatory cell infiltration, and markers of proteolysis in skeletal muscle would come about as a result of repeated eccentric exercise and that gender may affect this adaptive response. Untrained male (n = 8) and female (n = 8) subjects performed two bouts (bout 1 and bout 2), separated by 5.5 wk, of 36 repetitions of unilateral, eccentric leg press and 100 repetitions of unilateral, eccentric knee extension exercises (at 120% of their concentric single repetition maximum), the subjects' contralateral nonexercised leg served as a control (rest). Biopsies were taken from the vastus lateralis from each leg 24 h postexercise. After bout 2, the postexercise force deficit and the rise in serum creatine kinase (CK) activity were attenuated. Women had lower serum CK activity compared with men at all times (P < 0.05), but there were no gender differences in the relative magnitude of the force deficit. Muscle Z-disk streaming, quantified by using light microscopy, was elevated vs. rest only after bout 1 (P < 0.05), with no gender difference. Muscle neutrophil counts were significantly greater in women 24 h after bout 2 vs. rest and bout 1 (P < 0.05) but were unchanged in men. Muscle macrophages were elevated in men and women after bout 1 andbout 2 (P < 0.05). Muscle protein content of the regulatory calpain subunit remained unchanged whereas ubiquitin-conjugated protein content was increased after both bouts (P < 0.05), with a greater increase after bout 2. We conclude that adaptations to eccentric exercise are associated with attenuated serum CK activity and, potentially, an increase in the activity of the ubiquitin proteosome proteolytic pathway.

Crossing Bowen Street : mapping interventions in the classed subject

Synopsis: Crossing Bowen Street Crossing Bowen Street is an extended novel set in Melbourne, Australia. The protagonist, Meg Flanagan, is accepted to teachers' college. Meg is 24 years old and has worked, and lived out of home, since 17. Having completed her year 12 studies part time while working, she has applied to the Melbourne State College for a Bachelor of Education. Melbourne State College is subsequently 'amalgamated'A into Philip University, the original 19th century sandstone institution which borders MSC. Meg has worked as a medical secretary prior to commencing her studies. An only child, she is the first member of her family to go to university, indeed to finish high school. Tertiary study is exciting for Meg and the novel explores the psychic journey as well as the intellectual one, as Meg experiences challenges to the possibilities for her life and the trajectory along which she once assumed it would flow. The narrative is told through episodic and epistolary forms, with particular periods in Meg's cultural and academic life forming the focus, picking up the integral elements of her journey and examining the psychic context and action. Characters in the undergraduate chapters of the novel are somewhat transient, although very important to Meg's rapidly developing, changing sense of herself. The constant 'trying out' of ways of being and even lifestyles sees Meg losing old 'friendships' and making new, even temporary, ones all the time. This allows the opportunity for Meg to explore her feelings about connecting to others and the nature of her relationships. The Meg reflected back to her by others is of constant interest to her, particularly as she is frequently reminded that others see a very different Meg than she does. The novel commences at the outset of Meg's tertiary career, as she initially articulates the extent of her aspiration, of her sense of the possibility of her own life. Each vignette deals, chronologically, with an aspect of Meg's expanding sense of possibility, socially, emotionally, intellectually. Certain vignettes explore her relations with friends and acquaintances in the course, which in turn provide A In 1988, Federal Labor Minister for Education John Dawkins, devised a plan to end the streaming of Australian tertiary institutions and created what is called the Unified National System. This meant that colleges of advanced education and institutes of technology were either created universities in their own right, or more commonly, merged with an appropriate existing university. This process allows a fascinating insight into the class dimensions of hierarchies and stratifications. The need of universities and their members for status has been profoundly underscored. the background and context for her sexual relationships. That aspect of her developing subjectivity provides a marked contrast, which Meg uses as leverage, when set against her sense of herself as a scholar and her growing notion of entitlement, which allows her to 'choose', where previously she believed she had no choice; the choice is a scholarly career. Within all this, Meg discovers and is deeply empowered by certain political left, and feminist, discourses within the university community. She is equally dismayed and alienated by other feminist practices; her growing engagement with her own agency sees her quickly abandoning feminist subject positions previously dear to her, which served a particular purpose and are now superseded. This notion of feeling betrayed by the promise of a value system (or rather, its practitioners) will recur throughout the action of the novel, as Meg moves into an academic role, first as doctoral student and then as academic, seeking to live her values as practice and to remain true to what her trajectory has taught her. This is crystallised in the novel as the role played by the place she came from, and how that informs, and complicates, who she becomes. The novel seeks to explore the fundamental contradictions in doing so, through Meg's increasing awareness that the academy is not the harmonious, class aware institution she has idealised, but a world driven by status and hierarchies. This realisation must be reconciled in the light of Meg's anxieties about her working-class background. Meg's doctoral training at an elite university underscores her developing sense of what constitutes excellence and the role played by highly influential conservative institutions in maintaining social arrangements. As her academic career unfolds, the holding of a Cambridge PhD allows Meg opportunities to make change as certain privileges are afforded her by virtue of her Cambridge status. Yet it is this very notion that she seeks to challenge. Her growing passion for the State University of Victoria, an institution developed for the education of working-class people, informs her activism within the academy. Why are excellence and equity polarised? Why does the institution matter more than the scholarship? Why is so much practice within universities contrary to the values scholars often claim? These questions are explored through the dynamics of academic working life as student and later as a teacher at a university with an explicit equity agenda. The Start of the End (2003): The action commences on a late Friday after at SUV, when the Department of Communication & Cultural Studies has just been advised of Meg's promotion to Associate Professor. This vignette sees the initial soiree and celebrations and allows Meg to reflect on her experience. As her colleagues and friends are congratulating her, a particular student comes looking for Meg. It is clear that Angela Watson needs course advice particularly from Meg. Their discussion seems a straightforward one on the face of it, but it underscores many things; that Meg has come the full circle in her academic life, and what it is that her journey has really been about. The route to professorial appointment is considered, as is the source of Meg's greatest professional joy and fulfillment; is it scholarship, followed by leadership, in her discipline? It is knowing she has continued to speak and act to change the life chances of all students, wherever possible? Or is it the subtle distilling of both of these, along with the knowledge which emerges from the nexus of teaching and research. That scholarship, new knowledge, surely must be taking us somewhere specific in relation to others? The more we know, the more we can do...to what end? From this reflection, we see the action of the novel unfold. We return to this scene at the end of the novel, as Meg considers the trajectory of her life and its themes in her work. The novel ends as she is faced with the next challenge. Arrival (1989): Acceptance sees Meg as she is attempting to transform her life and create a new one. She has just been advised of her admission to an undergraduate Bachelor of Education program, at the major Melbourne teachers' college. Meg shares her rented home with her high school best friend, Anna, and her fiance, Jason, who appears to be superfluous in her life. Meg is aware he is a partner for who she used to be. We see Meg in her job as a medical secretary and this allows the mapping of Meg's sense of her own world, as she travels between home and work. This first stage of seeking her aspiration- to be an English teacher-evolves. As Meg considers the meaning of what she is about to do and how she knows it is right. This involves a consideration of what work means in our lives and how this is different for jobs according to how they are classed. Her relationship with the life she has known, the person she has been, is changing and this change is represented through her relationship with Jason. Meg's first day at teachers' college demonstrates that she is in a constant, often painful, dialogue with herself. The difficulties she encounters in making sense of the relation between her two 'lives' are thrown into sharp relief. The preparation for college sees Meg interrogating herself about how she can be different. Her initial experiences at the College resonate with her highest expectations of the life that awaits her, of the multiple possibilities currently being authored for her. Her first attendance at classes offers the opportunity to try out some of those possibilities, to test them against those she meets and to map the ways she could discover to 'be'. There is much tension and fear, but also endless excitement and these conflicting emotional states parallel and marble each other. It is on this day that she meets Jennifer Wren, her first real friend at university, who offers so many challenges to Meg. Their friendship involves a constant exhausting shift of subject positions, which Meg is able to look back on with affection in years to come. Going Bowling (1989): within a few weeks of commencing at university, Meg is socializing with some of her new friends, having neatly segmented her home and college lives. Meg has already realised that her friendships fall into separate groups; her friendship with Jennifer and the people Jennifer knows does not find its way into this group. They meet in the city to go bowling and have a meal. While Meg really enjoys these new people, already tensions are developing in relations between the group. Their unofficial leader, Rosemary Marshall, has a tendency to seek control and already resistance is showing. Rosemary particularly does not like Jennifer. Meg is enjoying her flirtation with Pete Danville, whom she has assumed to be gay. His very flattering attention has already developed Meg's confidence and stoked her ego, which has eroded in her stagnating relationship with Jason. Rosie has developed a crush on Pete and seems to take the flirtation with Meg personally. Dynamics in the group become slightly uncomfortable but Meg has grown quickly fond of her new friends, especially flamboyant Marina, another whom Rosemary seems to dislike. The discussions which occur during their evening deepen both the relationships and the tensions between them and draw lines which will determine the outcome of their various friendships. The Ball (1990): In the third year of her degree, much has happened to Meg. She is married to Jason, although she omits him from much of her psychic (and practical) life. Meg and her friends attend the Faculty's annual formal dinner dance. Meg has so far managed to balance the competitiveness which occurs between all of them, both academically and personally. The negotiation of her respective friendships with Jennifer and Marina requires a great deal of diplomacy; the subtext in this is very disturbing to Meg. What exactly is the conflict about? She can't be sure why they don't like each other; it could be Marina's smoking, or Jennifer's confidence to spare, but these things also annoy her, yet she does not fight with either girl as they do with each other. Rose has always insisted that the problem is Jennifer's private school background, but Marina went to a catholic girls' school, so what could the difference be? The ball is initially a happy occasion; the girls dress up and they dance and drink champagne together with the boys. But dynamics operating beneath the surface force their way up. Rosie is ready to force Pete to confront her continuing crush on him; Pete confronts Meg about their ongoing flirtation. Meg gives in and admits to herself for the first time that she does want to be with Pete. He is grown up and exciting and strong. He offers her something she has never had with Jason. Married less than a year, she pushes her husband out of her thoughts. The events of the ball force Meg to confront the differences between all her friends and the discomfort this affords everyone. Rosie's continued need for control over the group is acknowledged. Future Present (1991): Meg lives in Carlton with Pete. This is the busiest year thus far in her academic career and the financial, academic and emotional pressure is showing. This vignette gives us the range of Meg's academic activities and the way her life has fallen since the events at the ball eight months earlier. We see Meg grappling with her own evaluation of the changes in her 'way of being'; trying on different ways of living that she has idealised and finding them just as wanting as the last. Meg faces some key existential questions in this vignette and seeks answers which she finally discovers only she can give. Her relationship with Pete, the values and goals they share (and don't share) are thrown into sharp relief and provide a touchstone for the clearer determination of Meg's aspiration and future. Her relationship with various female friends is also revisited and this offers insight into Meg's constant checking of herself against idealised female templates. There is a crisis of identity and strength which constitutes an important fork in Meg's road. Beyond (1992): Beyond sees Meg determinedly seeking ways she can progress towards her goal, while still constantly checking against herself that postgraduate study (let alone a scholarly life) is available to her. We accompany Meg as she seeks and locates the academic path she wants; this is the backdrop for her further psychic exploration of the women who intimidate yet fascinate her, particularly Heloise Waul, who is a significant influence through Meg's postgraduate career. The sites in which Meg's personal struggles manifest are highlighted in this vignette, particularly in terms of dress and cultural pursuit. The conversations between Meg and Heloise also allow an exploration of the feminist politics of that milieu and the class tensions which operate tacitly within those politics. Bound to the Caucus (1992); Meg has now nearly completed her undergraduate degree and has been active for some time in university life and student politics. Her feminist and socialist education is well advanced. Bound to the Caucus shows us Meg in her student politics world for the first time, where the segue of her activism and academic life have taken her. Meg has found female friends who understand that part of her which struggles with inadequacy, although at this point in the novel this common struggle is not well understood or articulated. It is in this vignette that Meg admits her growing attraction for a Liberal student activist, Stuart Noble; this proscribed liaison raises many questions about values and aspiration, as well as the dominant sexual politics of the time and place. Bound to the Caucus also offers insight into the student activism occurring at universities like Philip in the early 1990s. Divergence (1993): Set in 1993, Meg is now in the early weeks of her honours program, although she has been at work on her thesis on the poet William Blake for some months. Living unhappily in a share household near the University, her relationship with Stuart Noble continues to develop, reaching a crisis point in this period. These events occur in the context of Meg's activist career in the Student Left, particularly as she encounters issues of identity around her class, feminism and difference amongst Left women. While Meg fights these battles passionately in an intense milieu, she considers them emotionally in terms of her changing sense of herself. Meg is increasingly aware that the personal impact of her class is changing for her. Additionally, she explores her relation with a 'boyfriend' of right wing political affiliation; Meg comes to recognise that this relationship is undermining her sense of herself in a way that her relationships with women in the left previously did. Honour Roll (1993): Meg is now undertaking honours and this vignette opens with Meg seeing the honours coordinator, Professor Michaela Moore, who approximates all those apparently middle-class traits to which Meg has such a push-pull relation. We see the return of a chapter of the honours thesis, discussion of the content and the constantly shifting subject positions these experiences offer Meg. This vignette also directly introduces Agnes. Mia and Agnes meet Meg after her supervision and this conversation allows very distinct if tacit class themes to develop. Meg has warmed quickly to Agnes, who is unlike anyone she has known; they have much in common in relation to their work and this binds them. Mia continually presents a viewpoint which irritates Meg, in relation to entitlement: to academic life, to funding, even to questioning how these things are enabled. Honour Roll allows us to see Meg's flourishing theoretical and intellectual life and its role in assisting her emotionally as she re-frames the same conundrums that previously constituted obstacles. The Cusp (1993): Meg's developing friendship with Agnes offers her enormous insights into difference and her developing sense of self and aspiration. While the girls come from diametrical backgrounds, they are united by their passion for their research and scholarly work. Meg is increasingly self-conscious through their discussions in terms of how she has seen herself and allowed herself to dream and seek. Cusp is set at the end of the honours year, prior to the release of results. Meg and Agnes explore their feelings about academia and this leads to discussions of purpose and the role of class within that. This vignette also documents Meg's growing social confidence and those aspects of herself which have become so sure to her, that she no longer considers them at all. Whom (1996): [Not included in this abridged edition]. Set at Cambridge, two thirds into Meg's doctorate, Whom shows Meg in the mental space which will take her back to Melbourne and the State University of Victoria. Having risen to the challenge of doctoral study, she is confronted now by deeper demons, and the need to explore and challenge them in the ambivalent context of Cambridge, which so excites her still, but which has proved empty of the profoundly held higher ideals she expected to see reflected. Set in the midst of Meg's doctoral study, this vignette is dramatically abridged in the submission novel. The importance of Whom lies in its concern with Meg's rapidly shifting sense of herself and her own scholarly subjectivity and the changes to these that the culture of Cambridge has wrought. By the second year of her PhD Meg is crystal clear about her goals and decides to spend the long break at home, rather than travelling, because she wishes to 'touch base' with her future. The action described segues into that in Courting the Enemy. Whom describes Meg's ambivalent and contradictory but passionate feelings about Cambridge. Whom demonstrates Meg's increasing anger at the status and privilege to which her education now automatically admits her, and her need to find some sort of stasis and safety in her emotional life. In this vignette, Meg meets her life partner, Jeremy McCallum (I have intentionally reduced the attention in the novel to Meg's romantic life as she matures into her career). Courting the Enemy (late 1990s): By this time, Meg is a senior lecturer in English at the State University of Victoria, which was established in the nineteenth century as the Worker's College. This vignette starts with Meg's attendance at a University Committee which is considering a transformation in relation to equity in admissions policy. Meg was drawn to SUV because of its transparent and determined commitment to educate the children of working-class people. An attack on the equity admission policy of her university galvanizes Meg and some of her colleagues. The action of the vignette considers the role of the scholar, and of such an institution as SUV, in the light of daily academic life. This vignette is primary in its demonstration of the themes of the novel. In the unabridged version, I took the opportunity to illustrate some of the vast range of administrative, intellectual and even physical demands on a senior scholar in the routine of academic life. In placing Meg in this context, I sought to highlight how a scholar of her values and commitment makes sense of the constantly shifting terrain of her working world and how this continually informs her practice. This vignette is also significant for its retrospective description of Meg's employment at SUV some years earlier. Locus: (1995). This piece of writing stands apart from the rest of the novel. I wished to write in a reflective voice, which might be from Meg's journal, were it not in the (omniscient) third person, in order to consider the headspace and meaning-making which occurs as Meg settles into Cambridge, and the lifestyle her situation allows her. Locus is a deeper engagement with Meg's sense of her identity. It considers the impact on her of the physical journeys she must make to match those of her psyche. These are thoughts too personal for a letter, even to Anna. Meg is exploring her ever shifting self and the growth in her self-belief allows her to explore what is rage; that she was bounded by illusions about her worth. Locus seeks to allow some context for Meg's anger at the role Cambridge plays. I seek to create the space in which Meg's dawning self understanding will lead her to her next, driven, purpose. Letters: throughout the novel letters are used to reveal and inform Meg's relationship with her family. This is an intentional device to distance the birth family in an attempt to blur and muddy an assessment of Meg's class through traditional measures. The letters between Meg and Aunty Jean particularly reveal much of the classed emotional antecedents of Meg's life. There are also letters exchanged with Meg's high school best friend, Anna, who has moved to the country and a very different lifestyle. Meg writes to Anna often, using the acceptance she feels in the friendship and her sense that Anna understands her, to touchstone her own emotional growth. Formal letters from institutions ring changes in settings and mark significant points in the geographical and academic trajectory of the character. All the letters serve to introduce time and event changes consistent with the episodic style of the narrative.

A cooperative cache architecture in support of caching multimedia objects in MANETs

This paper presents a cooperative caching architecture suitable for continuous media (CM) proxy caching in MANET environments. The proposed scheme introduces an application manager component, which is interposed between traditional Internet CM applications and the network layer. The application manager transparently performs data location and service migration of active CM streaming sessions so as to exploit nearby data sources based on the dynamic topology of a MANET. We propose two data location schemes - Cache-State - a link-state based scheme and Reactive - an on-demand scheme. Since service migration can occur frequently, the application manager uses soft-state signaling techniques to communicate between remote application managers by translating hard-state application signaling, such as Real Time Streaming Protocol (RTSP) into soft-state messages. The proposed schemes are evaluated through simulation studies using the NS simulator. Simulation studies show that both Cache-State and Reactive schemes demonstrate significant QoS improvements and reduced bandwidth consumption.

Determining dramatic intensification via flashing lights in movies

Movie directors and producers worldwide, in their quest to narrate a good story that warrants repeated audience viewing, use many cinematic elements to intensify and clarify the viewing experience. One such element that directors manipulate is lighting. In this paper we examine one aspect of lighting, namely flashing lights, and its role as an intensifier of dramatic effects in film. We present an algorithm for robust extraction of flashing lights and a simple mechanism to group detected flashing lights into flashing light scenes and analyze the role of these segments in story narration. In addition, we demonstrate how flashing lights detection can improve the performance of shot-based video segmentation. Experiments on a number of video sequences extracted from real movies yields good results. Our technique detects 90.4% of flashing lights. The detected flashing lights correctly eliminates 92.7% of false cuts in these sequences. In addition, data support is compiled to demonstrate the association between flashing light scenes and certain dramatic intensification events such as supernatural power, crisis or excitement.

Multimedia stream rate control over MANET based on router feedback

Streaming applications over Mobile Ad-hoc Networks (MANET) require a smooth transmission rate. The Internet is unable to provide this service during traffic congestion in the network. Designing congestion control for these applications is challenging, because the standard TCP congestion control mechanism is not able to handle the special properties of a shared wireless multi hop channel well. In particular, the frequent changes to the network topology and the shared nature of the wireless channel pose major challenges. In this paper, we propose a novel approach, which allows a quick increase of throughput by using explicit feedback from routers.

ChainCluster : engineering a cooperative content distribution framework for highway vehicular communications

The recent advances in wireless communication techniques have made it possible for fast-moving vehicles to download data from the roadside communications infrastructure [e.g., IEEE 802.11b Access Point (AP)], namely, Drive-thru Internet. However, due to the high mobility, harsh, and intermittent wireless channels, the data download volume of individual vehicle per drive-thru is quite limited, as observed in real-world tests. This would severely restrict the service quality of upper layer applications, such as file download and video streaming. On addressing this issue, in this paper, we propose ChainCluster, a cooperative Drive-thru Internet scheme. ChainCluster selects appropriate vehicles to form a linear cluster on the highway. The cluster members then cooperatively download the same content file, with each member retrieving one portion of the file, from the roadside infrastructure. With cluster members consecutively driving through the roadside infrastructure, the download of a single vehicle is virtually extended to that of a tandem of vehicles, which accordingly enhances the probability of successful file download significantly. With a delicate linear cluster formation scheme proposed and applied, in this paper, we first develop an analytical framework to evaluate the data volume that can be downloaded using cooperative drive-thru. Using simulations, we then verify the performance of ChainCluster and show that our analysis can match the simulations well. Finally, we show that ChainCluster can outperform the typical studied clustering schemes and provide general guidance for cooperative content distribution in highway vehicular communications.

Security from the transparent computing aspect

Transparent computing is an emerging computing paradigm where the users can enjoy any kind of service over networks on-demand with any devices, without caring about the underlying deployment details. In transparent computing, all software resources (even the OS) are stored on remote servers, from which the clients can request the resources for local execution in a block-streaming way. This paradigm has many benefits including cross-platform experience, user orientation, and platform independence. However, due to its fundamental features, e.g., separation of computation and storage in clients and servers respectively, and block-streaming-based scheduling and execution, transparent computing faces many new security challenges that may become its biggest obstacle. In this paper, we propose a Transparent Computing Security Architecture (TCSA), which builds user-controlled security for transparent computing by allowing the users to configure the desired security environments on demand. We envision, TCSA, which allows the users to take the initiative to protect their own data, is a promising solution for data security in transparent computing. © 2014 IEEE.

Bayesian nonparametric learning of contexts and activities from pervasive signals

This thesis develops machine learning techniques to discover activities and contexts from pervasive sensor data. These techniques are especially suitable for streaming sensor data as they can infer the context space automatically. They are applicable in many real world applications such as activity monitoring or organization management.

An alternative data collection scheduling scheme in wireless sensor networks

Despite significant advancements in wireless sensor networks (WSNs), energy conservation remains one of the most important research challenges. Recently, the problem of energy conservation has been addressed by applying mobile sink as an effective technique that can enhance efficiency of energy consumption in the networks. In this paper, the energy conservation problem is firstly formulated to maximize the lifetime of WSN subject to delay and node energy constraints. Then, to solve the defined energy conservation problem, a data collection scheduling with a mobile sink scheme is proposed. In the proposed approach, the sink movement is governed by a type-2 fuzzy controller to be located at the best location and time to collect sensory data. We conducted extensive experiments to study the effectiveness of the proposed protocol and compared it against the streaming data delivery (SDD) and virtual circle combined straight routing (VCCS) protocols. We observed that the proposed protocol outperforms both SDD and VCCS approaches by reducing energy consumption, minimize delays and enhance data collection quality.