Bounded real lemmas for positive descriptor systems

A well known result in the theory of linear positive systems is the existence of positive definite diagonal matrix (PDDM) solutions to some well known linear matrix inequalities (LMIs). In this paper, based on the positivity characterization, a novel bounded real lemma for continuous positive descriptor systems in terms of strict LMI is first established by the separating hyperplane theorem. The result developed here provides a necessary and sufficient condition for systems to possess H?H? norm less than ? and shows the existence of PDDM solution. Moreover, under certain condition, a simple model reduction method is introduced, which can preserve positivity, stability and H?H? norm of the original systems. An advantage of such method is that systems? matrices of the reduced order systems do not involve solving of LMIs conditions. Then, the obtained results are extended to discrete case. Finally, a numerical example is given to illustrate the effectiveness of the obtained results

Escala de agresión entre pares para adolescentes y principales resultados

The Peer Aggression (Bullying) Scale was translated, adapted, factor-analyzed, and validated on a sample of 607 adolescents from a middle school in Montevideo, Uruguay. After reviewing the phenomenon of peer aggression and the context in which this instrument was developed, the scale structure, which is comprised of four subscales, and its validation are described. Two subscales are associated with risk factors: the Outside Influence subscale (with two components, Norm-breaking Friends and Adult Attitudes toward Violence) and the Personal Attitude Toward Violence subscale (with two components, Facilitating Attitudes and Lack of Aggression-management Ability). The Prosocial Behavior subscale broadens the evaluation of peer aggression by sampling positive behavior. The Aggressive Behaviors subscale has three components: Fighting, Bullying, and Teasing. The psychometric properties of the four subscales are satisfactory. The main results are further analyzed by gender and age, on which significant differences consistent with the literature on peer aggression emerged.ResumenLa Escala de Agresión entre Pares (Bullying) se tradujo, adaptó, factorizó y validó en una muestra de 607 estudiantes secundarios de Montevideo, Uruguay. Se introducirá conceptualmente el fenómeno de Agresión entre Pares junto con el contexto en el cual se elaboró esta escala y se describirán su estructura y validación. La escala está compuesta por cuatro sub-escalas. Las dos primeras están asociadas a factores de riesgo: la Sub-Escala Influencias Externas (Conductas Transgresoras de Amigos y Actitud de Adultos sobre Violencia) y la Sub-Escala Actitud Personal hacia la Violencia (Actitud Facilitadora y Falta de Manejo de la Agresión). La Sub-Escala Conductas Prosociales amplía la comprensión del fenómeno aportando conductas positivas. En la cuarta sub-escala, Conductas Agresivas, surgieron tres dimensiones: Pelea, Intimidación y Burla. Las propiedades psicométricas son satisfactorias. En último término se presentan los resultados por género y edad que arrojan diferencias significativas consistentes con la literatura sobre esta temática.AbstractThe Peer Aggression (Bullying) Scale was translated, adapted, factor-analyzed, and validated on a sample of 607 adolescents from a middle school in Montevideo, Uruguay. After reviewing the phenomenon of peer aggression and the context in which this instrument was developed, the scale structure, which is comprised of four subscales, and its validation are described. Two subscales are associated with risk factors: the Outside Influence subscale (with two components, Norm-breaking Friends and Adult Attitudes toward Violence) and the Personal Attitude Toward Violence subscale (with two components, Facilitating Attitudes and Lack of Aggression-management Ability). The Prosocial Behavior subscale broadens the evaluation of peer aggression by sampling positive behavior. The Aggressive Behaviors subscale has three components: Fighting, Bullying, and Teasing. The psychometric properties of the four subscales are satisfactory. The main results are further analyzed by gender and age, on which significant differences consistent with the literature on peer aggression emerged