1,250 research outputs found
FIFO anomaly is unbounded
Virtual memory of computers is usually implemented by demand paging. For some
page replacement algorithms the number of page faults may increase as the
number of page frames increases. Belady, Nelson and Shedler constructed
reference strings for which page replacement algorithm FIFO produces near twice
more page faults in a larger memory than in a smaller one. They formulated the
conjecture that 2 is a general bound. We prove that this ratio can be
arbitrarily large
Signalling Storms in 3G Mobile Networks
We review the characteristics of signalling storms that have been caused by
certain common apps and recently observed in cellular networks, leading to
system outages. We then develop a mathematical model of a mobile user's
signalling behaviour which focuses on the potential of causing such storms, and
represent it by a large Markov chain. The analysis of this model allows us to
determine the key parameters of mobile user device behaviour that can lead to
signalling storms. We then identify the parameter values that will lead to
worst case load for the network itself in the presence of such storms. This
leads to explicit results regarding the manner in which individual mobile
behaviour can cause overload conditions on the network and its signalling
servers, and provides insight into how this may be avoided.Comment: IEEE ICC 2014 - Communications and Information Systems Security
Symposiu
Deficit Reduction Through Diversity: How Affirmative Action at the FCC Increased Auction Competition
In recent auctions for paging licenses, the Federal Communications Commission has granted businesses owned by minorities and women substantial bidding credits. In this article, Professors Ayres and Cramton analyze a particular auction and argue that the affirmative action bidding preferences, by increasing competition among auction participants, increased the government's revenue by $45 million. Subsidizing the participation of new bidders can induce established bidders to bid more aggressively. The authors conclude that this revenue- enhancing effect does not provide a sufficient constitutional justification for affirmative action-but when such justification is independently present, affirmative actions can cost the government much less than is currently thought.Auctions; Affirmative Action
Stationary Distribution of a Generalized LRU-MRU Content Cache
Many different caching mechanisms have been previously proposed, exploring
different insertion and eviction policies and their performance individually
and as part of caching networks. We obtain a novel closed-form stationary
invariant distribution for a generalization of LRU and MRU caching nodes under
a reference Markov model. Numerical comparisons are made with an "Incremental
Rank Progress" (IRP a.k.a. CLIMB) and random eviction (a.k.a. random
replacement) methods under a steady-state Zipf popularity distribution. The
range of cache hit probabilities is smaller under MRU and larger under IRP
compared to LRU. We conclude with the invariant distribution for a special case
of a random-eviction caching tree-network and associated discussion
Autonomous Accident Monitoring Using Cellular Network Data
Mobile communication networks constitute large-scale sensor networks that generate huge amounts of data that can be refined into collective mobility patterns. In this paper we propose a method for using these patterns to autonomously monitor and detect accidents and other critical events. The approach is to identify a measure that is approximately time-invariant on short time-scales under regular conditions, estimate the short and long-term dynamics of this measure using Bayesian inference, and identify sudden shifts in mobility patterns by monitoring the divergence between the short and long-term estimates. By estimating long-term dynamics, the method is also able to adapt to long-term trends in data. As a proof-of-concept, we apply this approach in a vehicular traffic scenario, where we demonstrate that the method can detect traffic accidents and distinguish these from regular events, such as traffic congestions
7. Paging. Virtual Memory.
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