29 resultados para frequency analysis problem


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Goal-directed problem solving as originally advocated by Herbert Simon’s means-ends analysis model has primarily shaped the course of design research on artificially intelligent systems for problem-solving. We contend that there is a definite disregard of a key phase within the overall design process that in fact logically precedes the actual problem solving phase. While systems designers have traditionally been obsessed with goal-directed problem solving, the basic determinants of the ultimate desired goal state still remain to be fully understood or categorically defined. We propose a rational framework built on a set of logically interconnected conjectures to specifically recognize this neglected phase in the overall design process of intelligent systems for practical problem-solving applications.

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This paper presents a new time-frequency approach to the underdetermined blind source separation using the parallel factor decomposition of third-order tensors. Without any constraint on the number of active sources at an auto-term time-frequency point, this approach can directly separate the sources as long as the uniqueness condition of parallel factor decomposition is satisfied. Compared with the existing two-stage methods where the mixing matrix should be estimated at first and then used to recover the sources, our approach yields better source separation performance in the presence of noise. Moreover, the mixing matrix can be estimated at the same time of the source separation process. Numerical simulations are presented to show the superior performance of the proposed approach to some of the existing two-stage blind source separation methods that use the time-frequency representation as well.

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Young people are a high risk group for gambling problems and university (college) students fall into that category. Given the high accessibility of gambling in Australia and its association with entertainment, students from overseas countries, particularly those where gambling is restricted or illegal, may be particularly vulnerable. This study examines problem gambling and its correlates among international and domestic university students using a sample of 836 domestic students (286 males; 546 females); and 764 international students (369 males; 396 females) at three Australian universities. Our findings indicate that although most students gamble infrequently, around 5 % of students are problem gamblers, a proportion higher than that in the general adult population. Popular gambling choices include games known to be associated with risk (cards, horse races, sports betting, casino games, and gaming machines) as well as lotto/scratch tickets. Males are more likely to be problem gamblers than females, and almost 10 % of male international students could be classified as problem gamblers. Hierarchical regression analysis showed that male gender, international student status, financial stress, negative affect and frequency of gambling on sports, horses/dogs, table games, casino gaming machines, internet casino games and bingo all significantly predicted problem gambling. Results from this study could inform gambling-education programs in universities as they indicate which groups are more vulnerable and specify which games pose more risk of problem gambling.

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Background
There is now considerable evidence that racism is a pernicious and enduring social problem with a wide range of detrimental outcomes for individuals, communities and societies. Although indigenous people worldwide are subjected to high levels of racism, there is a paucity of population-based, quantitative data about the factors associated with their reporting of racial discrimination, about the settings in which such discrimination takes place, and about the frequency with which it is experienced. Such information is essential in efforts to reduce both exposure to racism among indigenous people and the harms associated with such exposure.

Methods
Weighted data on self-reported racial discrimination from over 7,000 Indigenous Australian adults participating in the 2008–09 National Aboriginal and Torres Strait Islander Survey, a nationally representative survey conducted by the Australian Bureau of Statistics, were analysed by socioeconomic, demographic and cultural factors.

Results
More than one in four respondents (27%) reported experiencing racial discrimination in the past year. Racial discrimination was most commonly reported in public (41% of those reporting any racial discrimination), legal (40%) and work (30%) settings. Among those reporting any racial discrimination, about 40% experienced this discrimination most or all of the time (as opposed to a little or some of the time) in at least one setting. Reporting of racial discrimination peaked in the 35–44 year age group and then declined. Higher reporting of racial discrimination was associated with removal from family, low trust, unemployment, having a university degree, and indicators of cultural identity and participation. Lower reporting of racial discrimination was associated with home ownership, remote residence and having relatively few Indigenous friends.

Conclusions
These data indicate that racial discrimination is commonly experienced across a wide variety of settings, with public, legal and work settings identified as particularly salient. The observed relationships, while not necessarily causal, help to build a detailed picture of self-reported racial discrimination experienced by Indigenous people in contemporary Australia, providing important evidence to inform anti-racism policy.

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Critical analysis and problem-solving skills are two graduate attributes that are important in ensuring that graduates are well equipped in working across research and practice settings within the discipline of psychology. Despite the importance of these skills, few psychology undergraduate programmes have undertaken any systematic development, implementation, and evaluation of curriculum activities to foster these graduate skills. The current study reports on the development and implementation of a tutorial programme designed to enhance the critical analysis and problem-solving skills of undergraduate psychology students. Underpinned by collaborative learning and problem-based learning, the tutorial programme was administered to 273 third year undergraduate students in psychology. Latent Growth Curve Modelling revealed that students demonstrated a significant linear increase in self-reported critical analysis and problem-solving skills across the tutorial programme. The findings suggest that the development of inquiry-based curriculum offers important opportunities for psychology undergraduates to develop critical analysis and problem-solving skills. © 2013 The Australian Psychological Society.

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This study provides a systematic review of the empirical evidence related to the association between problem gambling and intimate partner violence (IPV). We identified 14 available studies in the systematic search (8 for victimisation only, 4 for perpetration only and 2 for both victimisation and perpetration). Although there were some equivocal findings, we found that most of the available research suggests that there is a significant relationship between problem gambling and being a victim of IPV. There was more consistent evidence that there is a significant relationship between problem gambling and perpetration of IPV. Meta-analyses revealed that over one third of problem gamblers report being victims of physical IPV (38.1%) or perpetrators of physical IPV (36.5%) and that the prevalence of problem gambling in IPV perpetrators is 11.3%. Although the exact nature of the relationships between problem gambling and IPV is yet to be determined, the findings suggest that less than full employment and clinical anger problems are implicated in the relationship between problem gambling and IPV victimization and that younger age, less than full employment, clinical anger problems, impulsivity, and alcohol and substance use are implicated in the relationship between problem gambling and IPV perpetration. The findings highlight the need for treatment services to undertake routine screening and assessment of problem gambling, IPV, alcohol and substance use problems, and mental health issues and provide interventions designed to manage this cluster of comorbid conditions. Further research is also required to investigate the relationship between problem gambling and violence that extends into the family beyond intimate partners.

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Comorbidity between problem gambling and internalising disorders (anxiety and depression) has long been recognised. However, it is not clear how these relationships develop, and what factors can foster resilience to both conditions. The current study draws on longitudinal cohort data to investigate: 1) the cross-sectional and longitudinal relationships between problem gambling and internalising symptoms; 2) whether there are common and/or specific social environmental factors protective against both internalising symptoms and problem gambling in young adulthood; and 3) interactive protective factors (i.e., those that moderate the relationship between problem gambling and internalising symptoms).

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 Determining an analytical solution to the inverse kinematics problem for a parallel manipulator is typically a straightforward problem. However, lower mobility parallel manipulators with 2-5 degrees of freedom (DOFs) often suffer from an unwanted parasitic motion in one or more DOFs. For such manipulators, the inverse kinematics problem can be significantly more difficult. This paper contains an analysis of the inverse kinematics problem for a class of 3-DOF parallel manipulators with axis-symmetric arm systems. All manipulators in the studied class exhibit parasitic motion in one DOF. For manipulators in the studied class, the general solution to the inverse kinematics problem is reduced to solving a univariate equation, while analytical solutions are presented for several important special cases.

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Social network analysis (SNA) is believed to be capable of revealing significant insights into crime and terror groups, including identifying important individuals and unique approaches to disruption. However, SNA has a number of theoretical and practical limitations, particularly when applied to ‘dark’ networks. While most analysts certainly acknowledge at least some of these limitations, we need to know more about their potential impact in a crime intelligence context. This article aims to go some way towards that end by placing greater scrutiny on the problem of ‘fuzzy boundaries’ when applied to small group networks. SNA is applied to the groups responsible for the 7 July 2005 London bombings and the 21 July 2005 attempted London bombings. The article concludes that while SNA is a valuable tool for understanding crime and terror groups, the age-old problem of fuzzy boundaries can have a profound impact on the analysis of small dynamic networks.

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OBJECTIVE: To inform public health approaches to problem gambling by examining how the news media covers problem gambling, with a particular focus on the causes, consequences and solutions to problem gambling, and the 'actors' and sources who influence media coverage. METHODS: A qualitative content analysis guided by framing theory analysed coverage of problem gambling in Australian newspapers in the period 1 July 2011 to 30 June 2012. RESULTS: Solutions to problem gambling were more frequently discussed than causes and consequences. A focus on the responsibility of individuals was preferred to reporting that focused on broader social, ecological, and industry determinants of problem gambling. Reporting was highly politicised, with politicians frequently quoted and political issues frequently discussed. In contrast, the community sector, health professionals and problem gamblers were rarely quoted. CONCLUSIONS AND IMPLICATIONS: This analysis has revealed the need for a more proactive, coordinated approach to the media by both public health researchers and health groups. The establishment of a gambling-specific coalition to push for evidence-based reform is recommended.

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Background: Discussions of gambling have traditionally focused on ideas of “problem” and “responsible” gambling. However, few studies have examined how Institutions attempt to exert social control over gamblers in order to promote so-called “responsible” behaviour. In this study, we examine the way “problem” and “responsible” gambling are discussed by Australian governments and the gambling industry, using a theoretical framework based on the work of Foucault.

Method
: We conducted a thematic analysis of discourses surrounding problem and responsible gambling in government and gambling industry websites, television campaigns and responsible gambling materials.

Results:
Documents distinguished between gambling, which was positive for the community, and problem gambling, which was portrayed as harmful and requiring medical intervention. The need for responsible gambling was emphasised in many of the documents, and reinforced by mechanisms including self-monitoring, self-control and surveillance of gamblers.

Conclusions:
Government and industry expect gamblers to behave “responsibly”, and are heavily influenced by neoliberal ideas of rational, controlled subjects in their conceptualisation of what constitutes “responsible behaviour”. As a consequence, problem gamblers become constructed as a deviant group. This may have significant consequences for problem gamblers, such as the creation of stigma.

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OBJECTIVE: The aim of this paper was to systematically review and meta-analyse the prevalence of co-morbid psychiatric disorders (DSM-IV Axis I disorders) among treatment-seeking problem gamblers. METHODS: A systematic search was conducted for peer-reviewed studies that provided prevalence estimates of Axis I psychiatric disorders in individuals seeking psychological or pharmacological treatment for problem gambling (including pathological gambling). Meta-analytic techniques were performed to estimate the weighted mean effect size and heterogeneity across studies. RESULTS: Results from 36 studies identified high rates of co-morbid current (74.8%, 95% CI 36.5-93.9) and lifetime (75.5%, 95% CI 46.5-91.8) Axis I disorders. There were high rates of current mood disorders (23.1%, 95% CI 14.9-34.0), alcohol use disorders (21.2%, 95% CI 15.6-28.1), anxiety disorders (17.6%, 95% CI 10.8-27.3) and substance (non-alcohol) use disorders (7.0%, 95% CI 1.7-24.9). Specifically, the highest mean prevalence of current psychiatric disorders was for nicotine dependence (56.4%, 95% CI 35.7-75.2) and major depressive disorder (29.9%, 95% CI 20.5-41.3), with smaller estimates for alcohol abuse (18.2%, 95% CI 13.4-24.2), alcohol dependence (15.2%, 95% CI 10.2-22.0), social phobia (14.9%, 95% CI 2.0-59.8), generalised anxiety disorder (14.4%, 95% CI 3.9-40.8), panic disorder (13.7%, 95% CI 6.7-26.0), post-traumatic stress disorder (12.3%, 95% CI 3.4-35.7), cannabis use disorder (11.5%, 95% CI 4.8-25.0), attention-deficit hyperactivity disorder (9.3%, 95% CI 4.1-19.6), adjustment disorder (9.2%, 95% CI 4.8-17.2), bipolar disorder (8.8%, 95% CI 4.4-17.1) and obsessive-compulsive disorder (8.2%, 95% CI 3.4-18.6). There were no consistent patterns according to gambling problem severity, type of treatment facility and study jurisdiction. Although these estimates were robust to the inclusion of studies with non-representative sampling biases, they should be interpreted with caution as they were highly variable across studies. CONCLUSIONS: The findings highlight the need for gambling treatment services to undertake routine screening and assessment of psychiatric co-morbidity and provide treatment approaches that adequately manage these co-morbid disorders. Further research is required to explore the reasons for the variability observed in the prevalence estimates.

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Green energy targets for coming decades advocates high penetration of wind energy in main energy matrix which also pose incendiary threat to stability and reliability of modern electric grid if their dynamic performance aspects are not assessed beforehand. Considering increasing interest in dynamic performance along with ancillary service assessment related to frequency regulation, development of suitable generic modeling has gained high priority. This paper presents modeling of type 4 full converter wind turbine generator system suitable for frequency regulation focusing on active power control. Complete model is a modification of WECC generic model with additional aerodynamic and pitch control model. Descriptions of individual sub models are presented and performance results are compared manufacturer specific GE type 4 WTG generic model by means of simulations in the MATLAB ® Power System Block set.

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The aim of this study was to systematically review and meta-analyze the prevalence of comorbid personality disorders among treatment-seeking problem gamblers. Almost one half (47.9%) of problem gamblers displayed comorbid personality disorders. They were most likely to display Cluster B disorders (17.6%), with smaller proportions reporting Cluster C disorders (12.6%) and Cluster A disorders (6.1%). The most prevalent personality disorders were narcissistic (16.6%), antisocial (14.0%), avoidant (13.4%), obsessive-compulsive (13.4%), and borderline (13.1%) personality disorders. Sensitivity analyses suggested that these prevalence estimates were robust to the inclusion of clinical trials and self-selected samples. Although there was significant variability in reported rates, subgroup analyses revealed no significant differences in estimates of antisocial personality disorder according to problem gambling severity, measure of comorbidity employed, and study jurisdiction. The findings highlight the need for gambling treatment services to conduct routine screening and assessment of co-occurring personality disorders and to provide treatment approaches that adequately address these comorbid conditions.