9,496 research outputs found

    Applications of fuzzy theories to multi-objective system optimization

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    Most of the computer aided design techniques developed so far deal with the optimization of a single objective function over the feasible design space. However, there often exist several engineering design problems which require a simultaneous consideration of several objective functions. This work presents several techniques of multiobjective optimization. In addition, a new formulation, based on fuzzy theories, is also introduced for the solution of multiobjective system optimization problems. The fuzzy formulation is useful in dealing with systems which are described imprecisely using fuzzy terms such as, 'sufficiently large', 'very strong', or 'satisfactory'. The proposed theory translates the imprecise linguistic statements and multiple objectives into equivalent crisp mathematical statements using fuzzy logic. The effectiveness of all the methodologies and theories presented is illustrated by formulating and solving two different engineering design problems. The first one involves the flight trajectory optimization and the main rotor design of helicopters. The second one is concerned with the integrated kinematic-dynamic synthesis of planar mechanisms. The use and effectiveness of nonlinear membership functions in fuzzy formulation is also demonstrated. The numerical results indicate that the fuzzy formulation could yield results which are qualitatively different from those provided by the crisp formulation. It is felt that the fuzzy formulation will handle real life design problems on a more rational basis

    The Integrated Psychosocial Model of Criminal Social Identity (IPM-CSI)

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    The integrated psychosocial model of criminal social identity attempts to synthesize, distil, and extend our knowledge and understanding of why people develop criminal social identity, with a particular focus on the psychological and social factors involved. We suggest that the development of criminal social identity results from a complex interplay of four important groups of psychosocial factors: (1) an identity crisis which results in weak bonds with society, peer rejection, and is associated with poor parental attachment and supervision; (2) exposure to a criminal/antisocial environment in the form of associations with criminal friends before, during, and/or after incarceration; (3) a need for identification with a criminal group in order to protect one’s self-esteem; and (4) the moderating role of personality traits in the relationship between criminal/antisocial environment and the development of criminal social identity. The model produces testable hypotheses and points to potential opportunities for intervention and prevention. Directions for future research are discussed

    Electromagnetic response of LaO_0.94F_0.06FeAs: AC susceptibility and microwave surface resistance

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    We discuss on the electromagnetic response of a polycrystalline sample of LaO_0.94F_0.06FeAs exposed to DC magnetic fields up to 10 kOe. The low- and high-frequency responses have been investigated by measuring the AC susceptibility at 100 kHz and the microwave surface resistance at 9.6 GHz. At low as well as high DC magnetic fields, the susceptibility strongly depends on the amplitude of the AC driving field, highlighting enhanced nonlinear effects. The field dependence of the AC susceptibility exhibits a magnetic hysteresis that can be justified considering the intragrain-field-penetration effects on the intergrain critical current density. The microwave surface resistance exhibits a clockwise magnetic hysteresis, which cannot be justified in the framework of the critical-state models of the Abrikosov-fluxon lattice; it may have the same origin as that detected in the susceptibility.Comment: 8 pages, 4 embedded eps figures; Proceedings of the 9th EUCAS Conference (Dresden, Germany, September 13-17, 2009

    Gender Differences in Risk and Protective factors for Resolved Plans and Preparations for Suicide among University Students

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    Background. Identifying the psychological predictors of suicide risk is essential because these variables may be amenable to change in treatment, unlike demographic or historical factors. Aims. The aim of this study was to examine the predictors of past two-week suicidal ideation for males and females separately. Method. Participants were 1184 healthy adults who completed an online survey. Results. A significant association between suicidal ideation and gender was found, such that mean levels were significantly higher in females than males. Separate regression analyses accounted for significant amounts of variance in suicide ideation, 54% for males and 68% for females. Moreover, the analyses revealed that suicide resilience Factor 2 (Emotional Stability) was a protective factor for both males and females; however, defeat, goal disengagement, and depression were independently associated with suicide ideation in males but not females. By contrast, entrapment, perceived burdensomeness, and hopelessness Factor 3 (Future Expectations) were significant risk factors only in females. Conclusions. The findings have clinical and practical implications, which may guide future practice, and supports the notion of targeted prevention and intervention strategies

    Facets of Psychopathy in Relation to Trauma-Exposure and Posttraumatic Stress Symptomology in a Sample of Incarcerated Male Offenders

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    Purpose: The aim was to investigate the moderating role of psychopathy facets on the relationship between traumatic exposure and posttraumatic stress disorder (PTSD) symptomology. Design/methodology/approach: Participants were male prisoners incarcerated in the U.K. Findings: The analysis revealed differential associations between the two facets of psychopathy, with potentially traumatic events and symptoms of PTSD. Specifically, neither primary psychopathy nor trauma exposure were significantly related to PTSD, while secondary psychopathy was positively and significantly related with PTSD symptoms. Furthermore, the effect of trauma exposure on PTSD was found to depend on the level of secondary psychopathy. More specifically, trauma exposure was strongly and positively associated with PTSD symptoms for low levels of secondary psychopathy and negatively associated with PTSD symptomology for individuals with high levels of secondary psychopathy. Originality/value: The findings clarify linkages among psychopathy facets, trauma, and PTSD, and extend our understanding of the presentation of PTSD in male prisoners

    Psychopathy, Gang membership, And moral disengagement among juvenile offenders

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    Purpose – The purpose of this paper is to investigate the impact of psychopathy factors and gang membership on moral disengagement while controlling for age, ethnicity, having run away from home, family member and/or friend arrests, substance misuse, parental physical fights, violence exposure (victimization and witnessing), and maternal warmth and hostility. Design/methodology/approach – The research is based on data collected from serious juvenile offenders (n=769) as part of the Pathways to Desistance Study. Findings – Six independent variables made a unique statistically significant contribution to the model: gang membership, age, gender, violence exposure, and psychopathy Factors 1 and 2. Psychopathy Factor 1 was the strongest predictor of moral disengagement. Originality/value – Results indicate that youth with heightened psychopathic traits make greater use of strategies to rationalize and justify their harmful behaviour against others. Implications in relation to theory and previous studies are discussed

    An Inverse Method for Policy-Iteration Based Algorithms

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    We present an extension of two policy-iteration based algorithms on weighted graphs (viz., Markov Decision Problems and Max-Plus Algebras). This extension allows us to solve the following inverse problem: considering the weights of the graph to be unknown constants or parameters, we suppose that a reference instantiation of those weights is given, and we aim at computing a constraint on the parameters under which an optimal policy for the reference instantiation is still optimal. The original algorithm is thus guaranteed to behave well around the reference instantiation, which provides us with some criteria of robustness. We present an application of both methods to simple examples. A prototype implementation has been done

    Can we use Hare’s psychopathy model within forensic and non-forensic populations? An empirical investigation

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    Although psychopathy construct (SRP-SF) was assessed among various samples, prior research did not investigate whether the model proposed by Hare and colleagues can be used to capture psychopathy scores derived from forensic and non-forensic populations. The main objective of the current study was to test dimensionality, construct validity, and factorial invariance of the SRP-SF within prison (N = 730) and student (N = 2,506) samples. Our results indicate that the SRP-SF measure cannot be used in the same way within forensic and non-forensic samples, which may be due to the inclusion of criminal/antisocial traits as an integral part of psychopathy
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