1,209 research outputs found
Genetic Programming for Smart Phone Personalisation
Personalisation in smart phones requires adaptability to dynamic context
based on user mobility, application usage and sensor inputs. Current
personalisation approaches, which rely on static logic that is developed a
priori, do not provide sufficient adaptability to dynamic and unexpected
context. This paper proposes genetic programming (GP), which can evolve program
logic in realtime, as an online learning method to deal with the highly dynamic
context in smart phone personalisation. We introduce the concept of
collaborative smart phone personalisation through the GP Island Model, in order
to exploit shared context among co-located phone users and reduce convergence
time. We implement these concepts on real smartphones to demonstrate the
capability of personalisation through GP and to explore the benefits of the
Island Model. Our empirical evaluations on two example applications confirm
that the Island Model can reduce convergence time by up to two-thirds over
standalone GP personalisation.Comment: 43 pages, 11 figure
Fitness landscape of the cellular automata majority problem: View from the Olympus
In this paper we study cellular automata (CAs) that perform the computational
Majority task. This task is a good example of what the phenomenon of emergence
in complex systems is. We take an interest in the reasons that make this
particular fitness landscape a difficult one. The first goal is to study the
landscape as such, and thus it is ideally independent from the actual
heuristics used to search the space. However, a second goal is to understand
the features a good search technique for this particular problem space should
possess. We statistically quantify in various ways the degree of difficulty of
searching this landscape. Due to neutrality, investigations based on sampling
techniques on the whole landscape are difficult to conduct. So, we go exploring
the landscape from the top. Although it has been proved that no CA can perform
the task perfectly, several efficient CAs for this task have been found.
Exploiting similarities between these CAs and symmetries in the landscape, we
define the Olympus landscape which is regarded as the ''heavenly home'' of the
best local optima known (blok). Then we measure several properties of this
subspace. Although it is easier to find relevant CAs in this subspace than in
the overall landscape, there are structural reasons that prevent a searcher
from finding overfitted CAs in the Olympus. Finally, we study dynamics and
performance of genetic algorithms on the Olympus in order to confirm our
analysis and to find efficient CAs for the Majority problem with low
computational cost
Cross-layer modeling and optimization of next-generation internet networks
Scaling traditional telecommunication networks so that they are able to cope with the volume of future traffic demands and the stringent European Commission (EC) regulations on emissions would entail unaffordable investments. For this very reason, the design of an innovative ultra-high bandwidth power-efficient network architecture is nowadays a bold topic within the research community. So far, the independent evolution of network layers has resulted in isolated, and hence, far-from-optimal contributions, which have eventually led to the issues today's networks are facing such as inefficient energy strategy, limited network scalability and flexibility, reduced network manageability and increased overall network and customer services costs. Consequently, there is currently large consensus among network operators and the research community that cross-layer interaction and coordination is fundamental for the proper architectural design of next-generation Internet networks.
This thesis actively contributes to the this goal by addressing the modeling, optimization and performance analysis of a set of potential technologies to be deployed in future cross-layer network architectures. By applying a transversal design approach (i.e., joint consideration of several network layers), we aim for achieving the maximization of the integration of the different network layers involved in each specific problem. To this end, Part I provides a comprehensive evaluation of optical transport networks (OTNs) based on layer 2 (L2) sub-wavelength switching (SWS) technologies, also taking into consideration the impact of physical layer impairments (PLIs) (L0 phenomena). Indeed, the recent and relevant advances in optical technologies have dramatically increased the impact that PLIs have on the optical signal quality, particularly in the context of SWS networks. Then, in Part II of the thesis, we present a set of case studies where it is shown that the application of operations research (OR) methodologies in the desing/planning stage of future cross-layer Internet network architectures leads to the successful joint optimization of key network performance indicators (KPIs) such as cost (i.e., CAPEX/OPEX), resources usage and energy consumption. OR can definitely play an important role by allowing network designers/architects to obtain good near-optimal solutions to real-sized problems within practical running times
Analysis of Genetic Variation of Western and Eastern Populations of Socotra Cormorant (Phalacrocorax Nigrogularis) In the UAE
Understanding the genetic structure of threatened and endangered species is important in management and conservation efforts. Measuring the pattern and scale of genetic variation within and among populations is important for understanding population dynamics. It helps us improve our understanding of the ecological and genetic relation between the populations. The current research looks at the population structure of the endemic seabird of the United Arab Emirates (UAE), the Socotra cormorant (Phalacrocorax nigrogularis). The lack of genetic information, increased threats, and small breeding habitats of the Socotra cormorants, makes it important to investigate the genetic population structure in the UAE. The aim of this research is to assess the level of genetic variation and structure within Eastern and Western Socotra Cormorant populations, using descriptive molecular genetic analysis. Using known mtDNA and nDNA primers of avian and cormorant species, we investigated the genetic differentiation and structure of the Socotra cormorants and assessed their genetic diversity. The results revealed that the Western and Eastern populations have low genetic differentiation and high gene flow. Also, they have low genetic diversity across all populations, which might indicate that the UAE population is recovering from a long-term bottleneck or an event of selective sweep. Now we have a closer insight into their genetic diversity, a further study of whole genome sequence (WGS) is required to get a better understanding of the population’s genetic history and dynamics. This will enable us to additionally understand the Socotra cormorant global population and their connectivity
Optimal Seismic Design of Steel Plate Shear Walls Using Metaheuristic Algorithms
In this paper three well-known metaheuristic algorithms comprising of Colliding Bodies Optimization, Enhanced Colliding Bodies Optimization, and Particle Swarm Optimization are employed for size and performance optimization of steel plate shear wall systems. Low seismic and high seismic optimal designs of these systems are performed according to the provisions of AISC 360 and AISC 341. In one part of the low seismic example, a moment frame and Steel Plate Shear Wall (SPW) strength are compared. Performance optimization of the Special Plate Shear Wall (SPSW) for size optimized system is one of the objectives of the high seismic example. Finally, base shear sensitivity analysis on optimal high seismic design of SPSW and size optimization of a 6-story to a 12-story SPSW are performed to have a comprehensive view on the optimal design of steel plate shear walls
Genetic-algorithm-optimized neural networks for gravitational wave classification
Gravitational-wave detection strategies are based on a signal analysis
technique known as matched filtering. Despite the success of matched filtering,
due to its computational cost, there has been recent interest in developing
deep convolutional neural networks (CNNs) for signal detection. Designing these
networks remains a challenge as most procedures adopt a trial and error
strategy to set the hyperparameter values. We propose a new method for
hyperparameter optimization based on genetic algorithms (GAs). We compare six
different GA variants and explore different choices for the GA-optimized
fitness score. We show that the GA can discover high-quality architectures when
the initial hyperparameter seed values are far from a good solution as well as
refining already good networks. For example, when starting from the
architecture proposed by George and Huerta, the network optimized over the
20-dimensional hyperparameter space has 78% fewer trainable parameters while
obtaining an 11% increase in accuracy for our test problem. Using genetic
algorithm optimization to refine an existing network should be especially
useful if the problem context (e.g. statistical properties of the noise, signal
model, etc) changes and one needs to rebuild a network. In all of our
experiments, we find the GA discovers significantly less complicated networks
as compared to the seed network, suggesting it can be used to prune wasteful
network structures. While we have restricted our attention to CNN classifiers,
our GA hyperparameter optimization strategy can be applied within other machine
learning settings.Comment: 25 pages, 8 figures, and 2 tables; Version 2 includes an expanded
discussion of our hyperparameter optimization mode
Shared genome analyses of notable listeriosis outbreaks, highlighting the critical importance of epidemiological evidence, input datasets and interpretation criteria
The persuasiveness of genomic evidence has pressured scientific agencies to supplement or replace well-established methodologies to inform public health and food safety decision-making. This study of 52 epidemiologically defined Listeria monocytogenes isolates, collected between 1981 and 2011, including nine outbreaks, was undertaken (1) to characterize their phylogenetic relationship at finished genome-level resolution, (2) to elucidate the underlying genetic diversity within an endemic subtype, CC8, and (3) to re-evaluate the genetic relationship and epidemiology of a CC8-delimited outbreak in Canada in 2008. Genomes representing Canadian Listeria outbreaks between 1981 and 2010 were closed and manually annotated. Single nucleotide variants (SNVs) and horizontally acquired traits were used to generate phylogenomic models. Phylogenomic relationships were congruent with classical subtyping and epidemiology, except for CC8 outbreaks, wherein the distribution of SNV and prophages revealed multiple co-evolving lineages. Chronophyletic reconstruction of CC8 evolution indicates that prophage-related genetic changes among CC8 strains manifest as PFGE subtype reversions, obscuring the relationship between CC8 isolates, and complicating the public health interpretation of subtyping data, even at maximum genome resolution. The size of the shared genome interrogated did not change the genetic relationship measured between highly related isolates near the tips of the phylogenetic tree, illustrating the robustness of these approaches for routine public health applications where the focus is recent ancestry. The possibility exists for temporally and epidemiologically distinct events to appear related even at maximum genome resolution, highlighting the continued importance of epidemiological evidence
On Easiest Functions for Mutation Operators in Bio-Inspired Optimisation
Understanding which function classes are easy and which are hard for a given algorithm is a fundamental question for the analysis and design of bio-inspired search heuristics. A natural starting point is to consider the easiest and hardest functions for an algorithm. For the (1+1) EA using standard bit mutation (SBM) it is well known that OneMax is an easiest function with unique optimum while Trap is a hardest. In this paper we extend the analysis of easiest function classes to the contiguous somatic hypermutation (CHM) operator used in artificial immune systems. We define a function MinBlocks and prove that it is an easiest function for the (1+1) EA using CHM, presenting both a runtime and a fixed budget analysis. Since MinBlocks is, up to a factor of 2, a hardest function for standard bit mutations, we consider the effects of combining both operators into a hybrid algorithm. We rigorously prove that by combining the advantages of k operators, several hybrid algorithmic schemes have optimal asymptotic performance on the easiest functions for each individual operator. In particular, the hybrid algorithms using CHM and SBM have optimal asymptotic performance on both OneMax and MinBlocks. We then investigate easiest functions for hybrid schemes and show that an easiest function for an hybrid algorithm is not just a trivial weighted combination of the respective easiest functions for each operator.publishersversionPeer reviewe
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