640 research outputs found
Integration of streaming services and TCP data transmission in the Internet
We study in this paper the integration of elastic and streaming traffic on a
same link in an IP network. We are specifically interested in the computation
of the mean bit rate obtained by a data transfer. For this purpose, we consider
that the bit rate offered by streaming traffic is low, of the order of
magnitude of a small parameter \eps \ll 1 and related to an auxiliary
stationary Markovian process (X(t)). Under the assumption that data transfers
are exponentially distributed, arrive according to a Poisson process, and share
the available bandwidth according to the ideal processor sharing discipline, we
derive the mean bit rate of a data transfer as a power series expansion in
\eps. Since the system can be described by means of an M/M/1 queue with a
time-varying server rate, which depends upon the parameter \eps and process
(X(t)), the key issue is to compute an expansion of the area swept under the
occupation process of this queue in a busy period. We obtain closed formulas
for the power series expansion in \eps of the mean bit rate, which allow us to
verify the validity of the so-called reduced service rate at the first order.
The second order term yields more insight into the negative impact of the
variability of streaming flows
Congestion analysis of unsignalized intersections
This paper considers an unsignalized intersection used by two traffic
streams. A stream of cars is using a primary road, and has priority over the
other, low-priority, stream. Cars belonging to the latter stream cross the
primary road if the gaps between two subsequent cars on the primary road is
larger than their critical headways. Questions that naturally arise are: given
the arrival pattern of the cars on the primary road, what is the maximum
arrival rate of low-priority cars such that the number of such cars remains
stable? In the second place, what can be said about the delay experienced by a
typical car at the secondary road? This paper addresses such issues by
considering a compact model that sheds light on the dynamics of the considered
unsignalized intersection. The model, which is of a queueing-theoretic nature,
reveals interesting insights into the impact of the user behavior on the above
stability and delay issues. The contribution of this paper is twofold. First,
we obtain new results for the aforementioned model with driver impatience.
Secondly, we reveal some surprising aspects that have remained unobserved in
the existing literature so far, many of which are caused by the fact that the
capacity of the minor road cannot be expressed in terms of the \emph{mean} gap
size; instead more detailed characteristics of the critical headway
distribution play a role.Comment: This paper appeared in the proceedings of the 8th International
Conference on Communication Systems and Networks (COMSNETS), 5-10 Jan. 2016.
A related but more extended paper which analyses a more general model than
the one in the present paper can be also found on arXiv:1802.0673
Mancebas de españoles, madres de mestizos. ImĂĄgenes de la mujer indĂgena en el PerĂș colonial temprano
25 p.Como sabemos, una buena parte de los hogares que los conquistadores
y primeros colonos constituyeron en Indias se sustentaron en sus inicios y
por un tiempo mĂĄs o menos prolongado, segĂșn los casos, en la convivencia
con una y a veces varias mujeres indĂgenas. Por lo general, estas uniones
de hecho parecen haberse quebrado con la incorporaciĂłn al hogar, en
calidad de esposa legĂtima, de una mujer de ascendencia europea, ya fuera
peninsular, criolla o incluso mestiza. Su irrupciĂłn supuso el desplazamiento
de aquellas primeras mujeres, que o bien tuvieron que abandonar la casa,
muchas veces dejando en ella a sus hijos mestizos, o bien pasaron a ocupar
en la intimidad cuartos traseros y a posiciones de segundo plano cara a la
vida pĂșblica.Peer reviewe
Why are undergraduate emerging adults anxious and avoidant in their romantic relationships? The role of family relationships
The exploration of and search for romantic relationships is one of the developmental tasks that characterise emerging adulthood, a new developmental phase halfway between adolescence and full adulthood. This study aims to explore, in a Mediterranean country, the existing relationships between the subjective perception of some parental behaviour and the anxiety and avoidance dimensions of attachment during emerging adulthood. To do so, 1,502 university students (903 women and 599 men) aged between 18 and 29 (M = 20.32 and SD = 2.13) completed a self-report questionnaire. The results revealed that perceived family support and perceived parental warmth were negatively associated with the avoidance and anxiety dimensions. In contrast, perceived parental control (both behavioural and psychological) was found to be positively associated with both attachment dimensions. Perceived behavioural control was also found to play a moderator role between perceived parental warmth and romantic attachment anxiety. Only in cases in which emerging adults of our sample perceived low levels of behavioural control was warmth found to be negatively associated with anxiety. The main conclusion of this work is the negative impact that parental control seems to have on romantic attachment during emerging adulthood. The results are discussed with a focus on the continuing importance of the family context in relation to the completion of developmental tasks, even during emerging adulthood.Ministerio de EconomĂa y Competitividad EDU2013-45687-RMinisterio de Ciencia, InnovaciĂłn y Universidades RTI2018-097405-B-I0
Note on the GI/GI/1 queue with LCFS-PR observed at arbitrary times
Consider the GI/GI/1 queue with the Last-Come First-Served Preemptive-Resume service discipline. We give intuitive explanations for (i) the geometric nature of the stationary queue length distribution and (ii) the mutual independence of the residual service requirements of the customers in the queue, both considered at arbitrary time points. These distributions have previously been established in the literature by either first considering the system at arrival instants or using balance equations. Our direct arguments provide further understanding of (i) and (ii)
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