163 research outputs found
Dynamic generation and attribution of revenues in a video platform
The consumption of online videos on the Internet grows every year, making it
a market that increasingly generates a greater volume of income. This paper
deals with a problem of great interest in this context: the allocation of the
generated revenues in a video website between the website and the video
creators. For this, we consider a dynamic model of the revenues generation. We
will consider that revenue can come from two sources: through the pay-per-view
system and through the insertion of advertisements in the videos. Then to study
how to divide the revenues in a reasonable and fair way between the two
parties, we consider a dynamic cooperative game that reflects the importance of
each part in generating revenue. From this game, we determine how its Shapley
value is and introduce other allocation rules derived from it. We provide a
structure of algorithm to calculate the Shapley value and its derived rules. We
show that the computational complexity of the algorithms is polynomial.
Finally, we provide some illustrative examples and simulations to illustrate
how the proposed allocation rules perform.Comment: 31 pages, 6 figure
Internet congestion control: From stochastic to dynamical models
Since its inception, control of data congestion on the Internet has been based on stochas tic models. One of the first such models was Random Early Detection. Later, this model
was reformulated as a dynamical system, with the average queue sizes at a router’s
buffer being the states. Recently, the dynamical model has been generalized to improve
global stability. In this paper we review the original stochastic model and both nonlin ear models of Random Early Detection with a two-fold objective: (i) illustrate how a
random model can be “smoothed out” to a deterministic one through data aggregation
and (ii) how this translation can shed light into complex processes such as the Internet
data traffic. Furthermore, this paper contains new materials concerning the occurrence
of chaos, bifurcation diagrams, Lyapunov exponents and global stability robustness with
respect to control parameters. The results reviewed and reported here are expected to
help design an active queue management algorithm in real conditions, that is, when sys tem parameters such as the number of users and the round-trip time of the data packets
change over time. The topic also illustrates the much-needed synergy of a theoretical
approach, practical intuition and numerical simulations in engineerin
Generalized TCP-RED dynamical model for Internet congestion control
Adaptive management of traffic congestion in the Internet is a complex problem that can
gain useful insights from a dynamical approach. In this paper we propose and analyze
a one-dimensional, discrete-time nonlinear model for Internet congestion control at the
routers. Specifically, the states correspond to the average queue sizes of the incoming
data packets and the dynamical core consists of a monotone or unimodal mapping with a
unique fixed point. This model generalizes a previous one in that additional control param eters are introduced via the data packet drop probability with the objective of enhancing
stability. To make the analysis more challenging, the original model was shown to exhibit
the usual features of low-dimensional chaos with respect to several system and control pa rameters, e.g., positive Lyapunov exponents and Feigenbaum-like bifurcation diagrams. We
concentrate first on the theoretical aspects that may promote the unique stationary state
of the system to a global attractor, which in our case amounts to global stability. In a sec ond step, those theoretical results are translated into stability domains for robust setting of
the new control parameters in practical applications. Numerical simulations confirm that
the new parameters make it possible to extend the stability domains, in comparison with
previous results. Therefore, the present work may lead to an adaptive congestion control
algorithm with a more stable performance than other algorithms currently in use
New RED-type TCP-AQM algorithms based on beta distribution drop functions
In recent years, Active Queue Management (AQM) mechanisms to improve the
performance of TCP/IP networks have acquired a relevant role. In this paper we
present a simple and robust RED-type algorithm together with a couple of
dynamical variants with the ability to adapt to the specific characteristics of
different network environments, as well as to the user needs. We first present
a basic version called Beta RED (BetaRED), where the user is free to adjust the
parameters according to the network conditions. The aim is to make the
parameter setting easy and intuitive so that a good performance is obtained
over a wide range of parameters. Secondly, BetaRED is used as a framework to
design two dynamic algorithms, which we will call Adaptive Beta RED (ABetaRED)
and Dynamic Beta RED (DBetaRED). In those new algorithms certain parameters are
dynamically adjusted so that the queue length remains stable around a
predetermined reference value and according to changing network traffic
conditions. Finally, we present a battery of simulations using the Network
Simulator 3 (ns-3) software with a two-fold objective: to guide the user on how
to adjust the parameters of the BetaRED mechanism, and to show a performance
comparison of ABetaRED and DBetaRED with other representative algorithms that
pursue a similar objective
DISCRIMINANT BINARY DATA REPRESENTATION FOR SPEAKER RECOGNITION
ABSTRACT In supervector UBM/GMM paradigm, each acoustic file is represented by the mean parameters of a GMM model. This supervector space is used as a data representation space, which has a high dimensionality. Moreover, this space is not intrinsically discriminant and a complete speech segment is represented by only one vector, withdrawing mainly the possibility to take into account temporal or sequential information. This work proposes a new approach where each acoustic frame is represented in a discriminant binary space. The proposed approach relies on a UBM to structure the acoustic space in regions. Each region is then populated with a set of Gaussian models, denoted as "specificities", able to emphasize speaker specific information. Each acoustic frame is mapped in the discriminant binary space, turning "on" or "off" all the specificities to create a large binary vector. All the following steps, speaker reference extraction, likelihood estimation or decision take place in this binary space. Even if this work is a first step in this avenue, the experiments based on NIST SRE 2008 framework demonstrate the potential of the proposed approach. Moreover, this approach opens the opportunity to rethink all the classical processes using a discrete, binary view
Orca-010, a Novel Potency-enhanced Oncolytic Adenovirus, Exerts Strong Antitumor Activity in Preclinical Models
Improving the antitumor potency of current oncolytic adenoviruses represents one of the major challenges in development of these viruses for clinical use. We have generated an oncolytic adenovirus carrying the safety-enhancing E1A Delta 24 deletion, the potency-enhancing T1 mutation, and the infectivity-enhancing fiber RGD modification. The results of in vitro cytotoxicity assays on 15 human cancer cell lines derived from different tumor types demonstrated that ORCA-010 is more potent than Ad5-Delta 24RGD or ONYX-015. As ORCA-010 will initially be developed for the treatment of prostate cancer, selectivity experiments were performed using primary human prostate cells. ORCA-010 killed cancer cells more effectively than these primary human cells. In both primary prostate fibroblasts and epithelial cells, ORCA-010 was as safe as Ad5-Delta 24RGD. Evaluation of ORCA-010 in in vivo xenograft tumor models in nude mice showed that ORCA-010 significantly inhibited growth of prostate, lung, and ovarian tumors and conferred prolonged survival of tumor-bearing animals. Furthermore, we observed a substantial increase in infectious viral particles in tumors injected with ORCA-010. The number of infectious viral particles increased after treatment and infectious particles remained present up to at least 4 weeks posttreatment. Intratumoral virus replication was associated with substantial necrosis and fibrosis. In conclusion, ORCA-010 is more potent than earlier generation oncolytic adenoviruses, without demonstrating increased toxicity. ORCA-010 exerted strong in vivo antitumor activity and is therefore a suitable candidate for clinical evaluation
The oncolytic adenovirus VCN-01 promotes anti-tumor effect in primitive neuroectodermal tumor models
Last advances in the treatment of pediatric tumors has led to an increase of survival rates of children affected by primitive neuroectodermal tumors, however, still a significant amount of the patients do not overcome the disease. In addition, the survivors might suffer from severe side effects caused by the current standard treatments. Oncolytic virotherapy has emerged in the last years as a promising alternative for the treatment of solid tumors. In this work, we study the anti-tumor effect mediated by the oncolytic adenovirus VCN-01 in CNS-PNET models. VCN-01 is able to infect and replicate in PNET cell cultures, leading to a cytotoxicity and immunogenic cell death. In vivo, VCN-01 increased significantly the median survival of mice and led to long-term survivors in two orthotopic models of PNETs. In summary, these results underscore the therapeutic effect ofVCN-01 for rare pediatric cancers such as PNETs, and warrants further exploration on the use of this virus to treat them
Tratamiento conservador para la resolución de lesiones cutáneas secundarias a una miasis
Se presenta un caso de lesiones cutáneas en la zona lumbar en un perro, como consecuencia de una miasis. El tratamiento más efectivo en este tipo de afecciones pasa por la retirada física de las larvas, aplicación de tratamientos antiparasitarios específicos y la resolución de las agresiones cutáneas producidas por la colonización y migración de las larvas. En el caso que se describe, el tratamiento para la resolución de estas lesiones se basó en la combinación de diferentes tratamientos tópicos con el objetivo de limpiar, desinfectar y eliminar el tejido necrótico, así como para controlar la infección y estimular la cicatrización y reepitelización de la zona
Ventilatory support in critically ill hematology patients with respiratory failure
Introduction: Hematology patients admitted to the ICU frequently experience respiratory failure and require mechanical ventilation. Noninvasive mechanical ventilation (NIMV) may decrease the risk of intubation, but NIMV failure poses its own risks. Methods: To establish the impact of ventilatory management and NIMV failure on outcome, data from a prospective, multicenter, observational study were analyzed. All hematology patients admitted to one of the 34 participating ICUs in a 17-month period were followed up. Data on demographics, diagnosis, severity, organ failure, and supportive therapies were recorded. A logistic regression analysis was done to evaluate the risk factors associated with death and NIVM failure. Results: Of 450 patients, 300 required ventilatory support. A diagnosis of congestive heart failure and the initial use of NIMV significantly improved survival, whereas APACHE II score, allogeneic transplantation, and NIMV failure increased the risk of death. The risk factors associated with NIMV success were age, congestive heart failure, and bacteremia. Patients with NIMV failure experienced a more severe respiratory impairment than did those electively intubated. Conclusions: NIMV improves the outcome of hematology patients with respiratory insufficiency, but NIMV failure may have the opposite effect. A careful selection of patients with rapidly reversible causes of respiratory failure may increase NIMV success
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