Search results for "Heuristic"

Improving the Representativeness of a Simple Random Sample: An Optimization Model and Its Application to the Continuous Sample of Working Lives

2020

This paper proposes an optimization model for selecting a larger subsample that improves the representativeness of a simple random sample previously obtained from a population larger than the population of interest. The problem formulation involves convex mixed-integer nonlinear programming (convex MINLP) and is, therefore, NP-hard. However, the solution is found by maximizing the size of the subsample taken from a stratified random sample with proportional allocation and restricting it to a p-value large enough to achieve a good fit to the population of interest using Pearson&rsquo

2014

The majority of next-generation sequencing short-reads can be properly aligned by leading aligners at high speed. However, the alignment quality can still be further improved, since usually not all reads can be correctly aligned to large genomes, such as the human genome, even for simulated data. Moreover, even slight improvements in this area are important but challenging, and usually require significantly more computational endeavor. In this paper, we present CUSHAW3, an open-source parallelized, sensitive and accurate short-read aligner for both base-space and color-space sequences. In this aligner, we have investigated a hybrid seeding approach to improve alignment quality, which incorp…

Non-participation modestly increased with distance to the examination clinic among adults in Finnish health examination surveys

2018

Aims: Health examination surveys (HES) provide important information about population health and health-related factors, but declining participation rates threaten the representativeness of collected data. It is hard to conduct national HESs at examination clinics near to every sampled individual. Thus, it is interesting to look into the possible association between the distance from home to the examination clinic and non-participation, and whether there is a certain distance after which the participation activity decreases considerably. Methods: Data from two national HESs conducted in Finland in 2011 and 2012 were used and a logistic regression model was fitted to investigate how distanc…

Capturing the Resilience of the Textile Companies as a Specific Response of the Fashion industry

2021

This chapter examines the most recent innovative activities of textile companies in Spain and their expansion into sanitary textiles and digitalization. In light of the global crisis caused by the COVID-19, we consider highly relevant to review the challenges of one of the most important fashion sectors, e.g., the textile industry, through this evolutionary period and the resilience of clusters. From this territorial perspective, we explained the industry’s restructuring and survival through three main elements: companies, relationships, and institutions. Companies are fundamental because they pave the way forward with their strategic responses. Relationships or clustering is the interactio…

Representative bureaucracy and seconded national government officials in the European Commission

2015

The bureaucratic arms of modern international organizations increasingly consist of staff with ambiguous organizational affiliations. This article analyses the implications of this trend from the perspective of representative bureaucracy – using seconded national experts (SNEs) in the European Commission (Commission) as the empirical laboratory. Using a variety of datasets, we unveil Commission SNEs' profiles (to assess their passive representativeness) and link these profiles to their role perceptions (to evaluate their potential for active representation). This illustrates that Commission SNEs' background characteristics do not match those of their constituent population (i.e. the EU27 po…

Arc crossing minimization in graphs with GRASP

2001

Graphs are commonly used to represent information in many fields of science and engineering. Automatic drawing tools generate comprehensible graphs from data, taking into account a variety of properties, enabling users to see important relationships in the data. The goal of limiting the number of arc crossings is a well-admitted criterion for a good drawing. In this paper, we present a Greedy Randomized Adaptive Search Procedure (GRASP) for the problem of minimizing arc crossings in graphs. Computational experiments with 200 graphs with up to 350 vertices are presented to assess the merit of the method. We show that simple heuristics are very fast but result in inferior solutions, while hig…

Optimization of Application-Specific L1 Cache Translation Functions of the LEON3 Processor

2020

Reconfigurable caches offer an intriguing opportunity to tailor cache behavior to applications for better run-times and energy consumptions. While one may adapt structural cache parameters such as cache and block sizes, we adapt the memory-address-to-cache-index mapping function to the needs of an application. Using a LEON3 embedded multi-core processor with reconfigurable cache mappings, a metaheuristic search procedure, and Mibench applications, we show in this work how to accurately compare non-deterministic performances of applications and how to use this information to implement an optimization procedure that evolves application-specific cache mappings.

Communities of Communication: Making Sense of the “Social” in Social Media

2012

As social media usage permeates people's lives, an increasing portion of their daily behavior leaves digital traces to be used by researchers. Social scientists can hope to gain new insight into the previously hidden but digitally recorded aspects of our digital social lives. Beyond aggregate and individual-level studies of user behavior, the digital traces also enable scientific examination of the structure of social interaction through networks. At the same time, the large scale and networked nature of social media data pose a new set of challenges to be overcome through the development of sound methodologies. We take stock of current methodological promises and challenges in social media…

A heuristic model-based approach for compensating wind effects in ski jumping.

2021

Wind influences the jump length in ski jumping, which raises questions about the fairness. To counteract the wind problem, the International Ski Federation has introduced a wind compensation system in 2009: time-averaged wind velocity components tangential to the landing slope are obtained from several sites along the landing slope, and these data are used in a linear statistical model for estimating the jump length effect of wind. This is considered in the total score of the ski jump. However, it has been shown that the jump length effect estimates can be inaccurate and misleading. The present manuscript introduces an alternative mathematical wind compensation approach that is based on an …

A Comparison of Multi-objective Algorithms for the Automatic Design Space Exploration of a Superscalar System

2013

In today’s computer architectures the design spaces are huge, thus making it very difficult to find optimal configurations. One way to cope with this problem is to use Automatic Design Space Exploration (ADSE) techniques. We developed the Framework for Automatic Design Space Exploration (FADSE) which is focused on microarchitectural optimizations. This framework includes several state-of-the art heuristic algorithms.