961 research outputs found
Finally eating soup with a knife? A historical perspective on the US Army's 2006 counterinsurgency doctrine
In 2006, the US Army adopted a new counterinsurgency (COIN) doctrine, Field Manual 3-24. The doctrine establishes new guidelines for conducting operations such as those currently taking place in Afghanistan and Iraq, where its validity is being tested. It is also a turning point in the US Army’s doctrinal approach to such operations as it fully embraces the “small war” approach to COIN. Earlier post-Vietnam Army doctrine has had an ambivalent view of the small war approach, which is contrary to the Army’s traditional preference for fighting big-scale, conventional wars. While earlier post-Vietnam COIN doctrines have used the conflicts in Vietnam and El Salvador as models, FM 3-24 takes into account many other possible forms of insurgency as well. It also recognizes more clearly the key role of popular legitimacy and accets a potentially much more extensive degree of Army involvement. Furthermore, FM 3-24 wholeheartedly argues that political concerns should take precedence over strictly military ones when applying force. COIN operations are viewed as a long-term commitment. The doctrine may help to fill a gap in US military capabilities, but this ultimately requires a change in the Army’s mindset and in US national strategic culture
Sparse Modeling of Grouped Line Spectra
This licentiate thesis focuses on clustered parametric models for estimation of line spectra, when the spectral content of a signal source is assumed to exhibit some form of grouping. Different from previous parametric approaches, which generally require explicit knowledge of the model orders, this thesis exploits sparse modeling, where the orders are implicitly chosen. For line spectra, the non-linear parametric model is approximated by a linear system, containing an overcomplete basis of candidate frequencies, called a dictionary, and a large set of linear response variables that selects and weights the components in the dictionary. Frequency estimates are obtained by solving a convex optimization program, where the sum of squared residuals is minimized. To discourage overfitting and to infer certain structure in the solution, different convex penalty functions are introduced into the optimization. The cost trade-off between fit and penalty is set by some user parameters, as to approximate the true number of spectral lines in the signal, which implies that the response variable will be sparse, i.e., have few non-zero elements. Thus, instead of explicit model orders, the orders are implicitly set by this trade-off. For grouped variables, the dictionary is customized, and appropriate convex penalties selected, so that the solution becomes group sparse, i.e., has few groups with non-zero variables. In an array of sensors, the specific time-delays and attenuations will depend on the source and sensor positions. By modeling this, one may estimate the location of a source. In this thesis, a novel joint location and grouped frequency estimator is proposed, which exploits sparse modeling for both spectral and spatial estimates, showing robustness against sources with overlapping frequency content. For audio signals, this thesis uses two different features for clustering. Pitch is a perceptual property of sound that may be described by the harmonic model, i.e., by a group of spectral lines at integer multiples of a fundamental frequency, which we estimate by exploiting a novel adaptive total variation penalty. The other feature, chroma, is a concept in musical theory, collecting pitches at powers of 2 from each other into groups. Using a chroma dictionary, together with appropriate group sparse penalties, we propose an automatic transcription of the chroma content of a signal
Joint DOA and Multi-Pitch Estimation Using Block Sparsity
In this paper, we propose a novel method to estimate the fundamental frequencies and directions-of-arrival (DOA) of multi-pitch signals impinging on a sensor array. Formulating the estimation as a group sparse convex optimization problem, we use the alternating direction of multipliers method (ADMM) to estimate both temporal and spatial correlation of the array signal. By first jointly estimating both fundamental frequencies and time-of-arrivals (TOAs) for each sensor and sound source, we then form a non-linear least squares estimate to obtain the DOAs. Numerical simulations indcate the preferable performance of the proposed estimator as compared to current state-of-the-art methods
Sparse Chroma Estimation for Harmonic Audio
This work treats the estimation of the chromagram for harmonic audio signals using a block sparse reconstruction framework. Chroma has been used for decades as a key tool in audio analysis, and is typically formed using a Fourier-based framework that maps the fundamental frequency of a musical tone to its corresponding chroma. Such an approach often leads to problems with tone ambiguity, which we avoid by taking into account the harmonic structure and perceptional attributes in music. The performance of the proposed method is evaluated using real audio files, clearly showing preferable performance as compared to other commonly used methods
A new method for normalized interpretation of antimicrobial resistance from disk test results for comparative purposes.
Objective To evaluate a calibration method for disk diffusion antibiotic susceptibility tests, using zone diameter values generated in the individual laboratory as the internal calibrator for combinations of antibiotic and bacterial species. Methods The high-zone side of zone histogram distributions was first analyzed by moving averages to determine the peak position of the susceptible population. The accumulated percentages of isolates for the high zone diameter values were calculated and converted into probit values. The normal distribution of the ideal population of susceptible strains was then determined by using the least-squares method for probit values against zone diameters, and the ideal population was thereby defined, including mean and standard deviation. Zone diameter values were obtained from laboratories at the Karolinska Hospital (KS) and Växjö Hospital (VX), and from two laboratories (LabA, LabB) in Argentina. The method relies on well standardized disk tests, but is independent of differences in MIC limits and zone breakpoints, and does not require the use of reference strains. Resistance was tentatively set at below 3 SD from the calculated, ideal mean zone diameter of the susceptible population. Results The method, called normalized interpretation of antimicrobial resistance, was tested on results from the KS and VX clinical microbiology laboratories, using the disk diffusion method for antimicrobial susceptibility tests, and for two bacterial species, Staphylococcus aureus and Escherichia coli. In total, 114 217 test results were included for the clinical isolates, and 3582 test results for control strains. The methodology at KS and VX followed the standard of the Swedish Reference Group for Antibiotics (SRGA). Zone diameter histograms for control strains were first analyzed to validate the procedure, and a comparison of actual means with the calculated means showed a correlation coefficient of r = 0.998. Results for clinical isolates at the two laboratories showed an excellent agreement for 54 of 57 combinations of antibiotic and bacterial species between normalized interpretations and the interpretations given by the laboratories. There were difficulties with E. coli and mecillinam, and S. aureus and tetracycline and rifampicin. The method was also tested on results from two laboratories using the NCCLS standard, and preliminary results showed very good agreement with quality-controlled laboratory interpretations. Conclusions The normalized resistance interpretation offers a new approach to comparative surveillance studies whereby the inhibition zone diameter results from disk tests in clinical laboratories can be used for calibration of the test
An Adaptive Penalty Approach to Multi-Pitch Estimation
This work treats multi-pitch estimation, and in particular the common misclassification issue wherein the pitch at half of the true fundamental frequency, here referred to as a sub-octave, is chosen instead of the true pitch. Extending on current methods which use an extension of the Group LASSO for pitch estimation, this work introduces an adaptive total variation penalty, which both enforce group- and block sparsity, and deal with errors due to sub-octaves. The method is shown to outperform current state-of-the-art sparse methods, where the model orders are unknown, while also requiring fewer tuning parameters than these. The method is also shown to outperform several conventional pitch estimation methods, even when these are virtued with oracle model orders
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Measuring the Effects of the TYC Gainesville Resocialization Program on Juvenile Offender Resiliency Levels
An analysis of the effects of resocialization programming on juvenile offender resiliency levels was conducted with 220 juveniles committed to a maximum security facility. Data were examined on the subjects' age, race/ethnicity, length of time at the facility, level of resocialization, and resiliency score. The resocialization programming contains cognitive and social components that would be instrumental in augmenting juvenile offender resiliency levels. Analysis of the variables did not show a significant increase in juvenile offender resiliency levels. The results did display that students who were at the facility longer and who were in the older age groups had higher levels of resocialization
"Sån naturlig grej att man måste väl ta p-piller liksom." -Resonemang kring preventivmedel av heterosexuella i parrelationer.
Abstract Authors: Maria Kronvall, Sofia Kuczkowski Titel:”Such a natural thing, that you have to be on the pill.” –Reflections on contraceptives among heterosexuals in relationships. Supervisor: Tove Harnett Assessor: David Hoff The aim of this study was to examine attitudes and preferences regarding contraceptives among heterosexuals in relationships. It examines how men and women choose contraceptives and why they make these choices in their relationship. We have interviewed 11 women and men in the ages between 21-33. 10 of them were interviewed as couples. All of the interviews were semi-structured and we followed a structure of different themes during the interviews. The informants were asked to describe their experiences with different contraceptives, and how they decided on their current method. We have organized the informants' answers in different categories such as; safety, side effects, cost and comfort. We found that most of the couples did not make their decision about contraceptives together as a result of a discussion. The priorities and the choices were mostly made by the women and they were also the ones who mainly took the responsibility and initiative regarding contraceptives. The majority of the women in this study had used birth control pills at some point in their current relationship. Most of the women felt skeptic and worried about taking hormones, but some continued to use the pill anyway. Compared to their girlfriends, the men talked very little about worrying. The women changed to another kind of birth control pill or tried a different method only if they experienced negative side effects, or were strongly against taking hormones. Condoms were only used as a second choice and in many cases as a last resort. It was mostly seen as a temporary contraceptive in periods of being single, or in the beginning of a relationship. Both men and women agreed with the perception that men don't like to use condoms. Men who see condoms as a long term contraceptive were seen as exceptions
Sparse Multi-Pitch and Panning Estimation of Stereophonic Signals
In this paper, we propose a novel multi-pitch estimator for stereophonic mixtures, allowing for pitch estimation on multi-channel audio even if the amplitude and delay panning parameters are unknown. The presented method does not require prior knowledge of the number of sources present in the mixture, nor on the number of harmonics in each source. The estimator is formulated using a sparse signal framework, and an efficient implementation using the ADMM is introduced. Numerical simulations indicate the preferable performance of the proposed method as compared to several commonly used multi-channel single pitch estimators, and a commonly used multi-pitch estimator
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