19,640 research outputs found

    «The Karma of Chicken Curry». Tibetan Masala films and youth narratives of exile

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    This essay offers a preliminary study of the cultural translation practices by young Tibetan exilic filmmakers in India, whose films, rather than rejecting the masala formula offered by Bollywood, have tentatively adapted it to the expectations of a Tibetan diasporic audience looking for a cinema capable of attending to the escapist needs of their minds while simultaneously catering to the intimate dreams of their hearts. I contend that Tashi Wangchuk and Tsultrim Dorjee’s first long feature Phun Anu Thanu (Two Exiled Brothers, 2006) is as an original film that presents a new offer on the menu of Tibetan diasporic films, a kind of spicy curry that has been advocated as a timely necessity and a yet-to-be-fulfilled desire

    Sequential nonideal measurements of quantum oscillators: Statistical characterization with and without environmental coupling

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    A one-dimensional quantum oscillator is monitored by taking repeated position measurements. As a first con- tribution, it is shown that, under a quantum nondemolition measurement scheme applied to a system initially at the ground state, (i) the observed sequence of measurements (quantum tracks) corresponding to a single experiment converges to a limit point, and that (ii) the limit point is random over the ensemble of the experiments, being distributed as a zero-mean Gaussian random variable with a variance at most equal to the ground-state variance. As a second contribution, the richer scenario where the oscillator is coupled with a frozen (i.e., at the ground state) ensemble of independent quantum oscillators is considered. A sharply different behavior emerges: under the same measurement scheme, here we observe that the measurement sequences are essentially divergent. Such a rigorous statistical analysis of the sequential measurement process might be useful for characterizing the main quantities that are currently used for inference, manipulation, and monitoring of many quantum systems. Several interesting properties of the quantum tracks evolution, as well as of the associated (quantum) threshold crossing times, are discussed and the dependence upon the main system parameters (e.g., the choice of the measurement sampling time, the degree of interaction with the environment, the measurement device accuracy) is elucidated. At a more fundamental level, it is seen that, as an application of basic quantum mechanics principles, a sharp difference exists between the intrinsic randomness unavoidably present in any quantum system, and the extrinsic randomness arising from the environmental coupling, i.e., the randomness induced by an external source of disturbance.Comment: pages 16 Figures

    Learning from Profession Knowledge: Application on Knitting

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    Knowledge Management is a global process in companies. It includes all the processes that allow capitalization, sharing and evolution of the Knowledge Capital of the firm, generally recognized as a critical resource of the organization. Several approaches have been defined to capitalize knowledge but few of them study how to learn from this knowledge. We present in this paper an approach that helps to enhance learning from profession knowledge in an organisation. We apply our approach on knitting industry

    Multi-layer virtual transport network design

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    Service overlay networks and network virtualization enable multiple overlay/virtual networks to run over a common physical network infrastructure. They are widely used to overcome deficiencies of the Internet (e.g., resiliency, security and QoS guarantees). However, most overlay/virtual networks are used for routing/tunneling purposes, and not for providing scoped transport flows (involving all mechanisms such as error and flow control, resource allocation, etc.), which can allow better network resource allocation and utilization. Most importantly, the design of overlay/virtual networks is mostly single-layered, and lacks dynamic scope management, which is important for application and network management. In response to these limitations, we propose a multi-layer approach to Virtual Transport Network (VTN) design. This design is a key part of VTN-based network management, where network management is done via managing various VTNs over different scopes (i.e., ranges of operation). Our simulation and experimental results show that our multi-layer approach to VTN design can achieve better performance compared to the traditional single-layer design used for overlay/virtual networks.This work has been partly supported by National Science Foundation awards: CNS-0963974 and CNS-1346688

    SDN management layer: design requirements and future direction

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    Computer networks are becoming more and more complex and difficult to manage. The research community has been expending a lot of efforts to come up with a general management paradigm that is able to hide the details of the physical infrastructure and enable flexible network management. Software Defined Networking (SDN) is such a paradigm that simplifies network management and enables network innovations. In this survey paper, by reviewing existing SDN management layers (platforms), we identify the general common management architecture for SDN networks, and further identify the design requirements of the management layer that is at the core of the architecture. We also point out open issues and weaknesses of existing SDN management layers. We conclude with a promising future direction for improving the SDN management layer.This work is supported in part by the National Science Foundation (NSF grant CNS-0963974)

    An Adaptive Policy Management Approach to BGP Convergence

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    The Border Gateway Protocol (BGP) is the current inter-domain routing protocol used to exchange reachability information between Autonomous Systems (ASes) in the Internet. BGP supports policy-based routing which allows each AS to independently adopt a set of local policies that specify which routes it accepts and advertises from/to other networks, as well as which route it prefers when more than one route becomes available. However, independently chosen local policies may cause global conflicts, which result in protocol divergence. In this paper, we propose a new algorithm, called Adaptive Policy Management Scheme (APMS), to resolve policy conflicts in a distributed manner. Akin to distributed feedback control systems, each AS independently classifies the state of the network as either conflict-free or potentially-conflicting by observing its local history only (namely, route flaps). Based on the degree of measured conflicts (policy conflict-avoidance vs. -control mode), each AS dynamically adjusts its own path preferences—increasing its preference for observably stable paths over flapping paths. APMS also includes a mechanism to distinguish route flaps due to topology changes, so as not to confuse them with those due to policy conflicts. A correctness and convergence analysis of APMS based on the substability property of chosen paths is presented. Implementation in the SSF network simulator is performed, and simulation results for different performance metrics are presented. The metrics capture the dynamic performance (in terms of instantaneous throughput, delay, routing load, etc.) of APMS and other competing solutions, thus exposing the often neglected aspects of performance.National Science Foundation (ANI-0095988, EIA-0202067, ITR ANI-0205294

    Impact of Physical Activity on Stress Levels and Methadone Maintenance Treatment Outcomes

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    Introduction: While the opioid epidemic has continued to intensify over the last decade, unfortunately the likelihood of achieving stable long-term abstinence using methadone maintenance treatment (MMT) remains as low as 60 percent. Perceived stress has been identified as a factor predictive of premature termination and relapse, making stress reduction an important area of study in MMT. However, little research is available on the effects of active stress-coping mechanisms on MMT outcomes. Objective: To address this gap, the current study was conducted to examine the impact of physical activity on stress reduction and treatment outcomes. Methods: This was a retrospective cohort study in which ninety-three consecutive admissions to a university sponsored, community-based, outpatient medication-assisted treatment facility in Pennsylvania were reviewed. The 46 individuals (49.5%) who remained active in treatment at 6 months post-admission represented the study sample. Thirty-four of these individuals completed an initial assessment with the 4-item Perceived Stress Scale (PSS4) allowing investigators to determine stress levels at admission. The 27 individuals scoring above the 25th percentile were categorized as “high stress” and retained for further interviewing. Of these 27 individuals, 22 completed both the 10-item Perceived Stress Scale (PSS10) to assess stress levels at approximately 6 months post-admission as well the Global Physical Activity Questionnaire (GPAQ), which measured physical activity levels at admission and 6 months post-admission. Results: The mean age at time of study was 40. 52± 11.84 years; 68% of study participants were male, 65% were Caucasian, 79% were unemployed, and 91% were unmarried. In the first 180 days of treatment, subjects were dosed on average of 164.02 days (91. 1%) with the average dose equaling 85. 40± 40.2 milligrams per day. Consistent with prior research, results indicated that stress levels dropped significantly from admission to 6 months post-entry from a mean stress level of 2. 82±.59 to 1.88±. 80, t(22)=4. 971, p Conclusion: Our data, based on a limited sample, suggests that treatment is associated with decreased levels of stress levels in this population. Interestingly, patients attributed their decreased physical activity levels to reduced or nonexistent drug-seeking activity, as well as to the demanding time-commitment of MMT. Our failure to find significant effects of exercise may be a consequence of sampling procedures and sample size. To better address this question, future controlled studies might focus on incorporating physical exercise in MMT treatment to determine if those who regularly engage in physical activity demonstrate better outcomes in MMT. Identification of positive effects will allow the medical community to introduce non-pharmaceutical approaches to the treatment of opioid use disorders

    Differentiated Predictive Fair Service for TCP Flows

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    The majority of the traffic (bytes) flowing over the Internet today have been attributed to the Transmission Control Protocol (TCP). This strong presence of TCP has recently spurred further investigations into its congestion avoidance mechanism and its effect on the performance of short and long data transfers. At the same time, the rising interest in enhancing Internet services while keeping the implementation cost low has led to several service-differentiation proposals. In such service-differentiation architectures, much of the complexity is placed only in access routers, which classify and mark packets from different flows. Core routers can then allocate enough resources to each class of packets so as to satisfy delivery requirements, such as predictable (consistent) and fair service. In this paper, we investigate the interaction among short and long TCP flows, and how TCP service can be improved by employing a low-cost service-differentiation scheme. Through control-theoretic arguments and extensive simulations, we show the utility of isolating TCP flows into two classes based on their lifetime/size, namely one class of short flows and another of long flows. With such class-based isolation, short and long TCP flows have separate service queues at routers. This protects each class of flows from the other as they possess different characteristics, such as burstiness of arrivals/departures and congestion/sending window dynamics. We show the benefits of isolation, in terms of better predictability and fairness, over traditional shared queueing systems with both tail-drop and Random-Early-Drop (RED) packet dropping policies. The proposed class-based isolation of TCP flows has several advantages: (1) the implementation cost is low since it only requires core routers to maintain per-class (rather than per-flow) state; (2) it promises to be an effective traffic engineering tool for improved predictability and fairness for both short and long TCP flows; and (3) stringent delay requirements of short interactive transfers can be met by increasing the amount of resources allocated to the class of short flows.National Science Foundation (CAREER ANI-0096045, MRI EIA-9871022

    Describing and Forecasting Video Access Patterns

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    Computer systems are increasingly driven by workloads that reflect large-scale social behavior, such as rapid changes in the popularity of media items like videos. Capacity planners and system designers must plan for rapid, massive changes in workloads when such social behavior is a factor. In this paper we make two contributions intended to assist in the design and provisioning of such systems.We analyze an extensive dataset consisting of the daily access counts of hundreds of thousands of YouTube videos. In this dataset, we find that there are two types of videos: those that show rapid changes in popularity, and those that are consistently popular over long time periods. We call these two types rarely-accessed and frequently-accessed videos, respectively. We observe that most of the videos in our data set clearly fall in one of these two types. For each type of video we ask two questions: first, are there relatively simple models that can describe its daily access patterns? And second, can we use these simple models to predict the number of accesses that a video will have in the near future, as a tool for capacity planning? To answer these questions we develop two different frameworks for characterization and forecasting of access patterns. We show that for frequently-accessed videos, daily access patterns can be extracted via principal component analysis, and used efficiently for forecasting. For rarely-accessed videos, we demonstrate a clustering method that allows one to classify bursts of popularity and use those classifications for forecasting

    Managing NFV using SDN and control theory

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    Control theory and SDN (Software Defined Networking) are key components for NFV (Network Function Virtualization) deployment. However little has been done to use a control-theoretic approach for SDN and NFV management. In this paper, we describe a use case for NFV management using control theory and SDN. We use the management architecture of RINA (a clean-slate Recursive InterNetwork Architecture) to manage Virtual Network Function (VNF) instances over the GENI testbed. We deploy Snort, an Intrusion Detection System (IDS) as the VNF. Our network topology has source and destination hosts, multiple IDSes, an Open vSwitch (OVS) and an OpenFlow controller. A distributed management application running on RINA measures the state of the VNF instances and communicates this information to a Proportional Integral (PI) controller, which then provides load balancing information to the OpenFlow controller. The latter controller in turn updates traffic flow forwarding rules on the OVS switch, thus balancing load across the VNF instances. This paper demonstrates the benefits of using such a control-theoretic load balancing approach and the RINA management architecture in virtualized environments for NFV management. It also illustrates that GENI can easily support a wide range of SDN and NFV related experiments
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