On the achievable tracking performance of NCSs over SNR limited channels

In this paper, the achievable tracking performance limitations of discrete-time, multi-input multi-output (MIMO) networked control systems (NCSs) are studied. The channel is modeled as an additive white Gaussian noise and signal-to-noise ratio (SNR) limited channel with feedback. Under this framework, the closed relationships among stabilization, tracking performance, and SNR limited are quantitatively revealed. Some new results a.erived according to the allpass factorization and Youla parameterization of two degrees of freedom controller. The results show that the best tracking performance is in connection with the unstable poles, non-minimum phase zeros of the system. It is also demonstrated that the tracking performance will be badly degraded by feedback channel noise and due to the SNR limited. Finally, a simulation example is presented to validate the conclusions.     

Abnormal emotional processing in maltreated children diagnosed of Complex Posttraumatic Stress Disorder

Maltreated children usually show a specific pattern of emotional and behavioral symptoms that exceed those relating to posttraumatic stress disorder (PTSD). These symptoms have been defined as Complex PTSD (CPTSD). The underlying attentional mechanisms of abnormal emotional processing and their relation to the clinical presentation of CPTSD are not well understood. A visual dot-probe paradigm involving pre-attentive (i.e., 500 ms) and attentive (i.e., 1500 ms) presentation rates of neutral versus emotional (i.e., angry, happy or sad) facial expressions was applied. Twenty-one maltreated CPTSD children were compared with twenty-six controls. The results are as follows: an attention bias away from threatening faces and an attentional bias towards sad faces were observed in maltreated CPTSD children during pre-attentive and attentive processing. Whereas the attentional bias away from angry faces was associated with social problems, the attentional bias towards sad faces was associated with depressive and withdrawn symptoms. Therefore, CPTSD children develop maladaptive negative cognitive styles, which may underlie not only social problems (by a cognitive avoidance of threatening stimuli) but also depressive symptoms (by a cognitive approach to sad stimuli). Attention processing abnormalities should be considered as therapeutic targets for new treatment approaches in this population.     

Children’s trauma-related symptoms following complex trauma exposure: Evidence of gender differences

Complex trauma exposure has been operationalized as multiple or chronic interpersonal traumas that begin early in life and is thought to result in widespread self-regulation difficulties across several domains of functioning. Prior research has demonstrated that there are gender differences in trauma exposure as well as trauma-related symptoms; however, gender discrepancies have not previously been examined in the context of child survivors of complex trauma. The aim of the present study was to determine whether there are gender differences in both caregiver and child-reported trauma exposure and symptoms among 167 children who have experienced complex trauma (3–18 years, M = 9.90, SD = 3.92; 61.67% female). Male children were somewhat more likely to have been exposed to domestic violence, while female children were more likely to have experienced sexual abuse as well as more likely to have been abused by a caregiver. Gender differences were observed for several of the caregiver-reported symptom domains, with female children exhibiting higher levels of depression, dissociation, posttraumatic stress disorder (PTSD) hyperarousal symptoms, and total PTSD symptoms. Female children also self-reported higher levels of sexual concerns, and marginally more re-experiencing and total PTSD symptoms. Secondary analyses utilizing only children who experienced sexual abuse revealed that gender differences largely remained, again with females manifesting higher levels of symptoms. Thus, following complex trauma, female children may be at higher risk for trauma-related difficulties, which has implications for research and clinical interventions.     

Men’s experiences of early life trauma and pathways into long-term homelessness

Previous studies that have explored the association between childhood trauma and homelessness indicate that traumatic events can lead to survivor distrust of interpersonal relationships and institutions, prolonged homelessness and poor health and social outcomes. The majority of this literature relies on quantitative data and fails to investigate the personal experiences of childhood trauma that are found to impact housing status later in life. Semi-structured, qualitative interviews were conducted with 25 men living in an urban area in Ontario who had spent more than 30 consecutive nights in an emergency shelter over the course of their housing histories. During data analysis, it was observed that all of the men had experienced some form of trauma or neglect in childhood which contributed to their entries into homelessness. Using a case study approach, three entry pathways into long term homelessness are described: 1) youth; 2) emerging or early adulthood; and 3) middle adulthood. Participants are classified into the pathways by the developmental period at which they first entered homelessness. These findings have implications for policy makers and service providers, as key intervention points are identified. Establishing effective interventions that address crises experienced at these points could assist with homelessness prevention across the life course.     

俄狄浦斯情结的中西方异同比较

俄狄浦斯情结是中西方文学中共同的文学主题,他们之间既有相似之处,即都表现了父母子三者之间的三角关系,又有完全不同的表现形式,西方更为直接,表现为破禁之后的惩罚,而在中国文化中则表现比较隐晦,而且中国文化将孝引入心理机制从而从根源上消解了这种乱伦的出现。不同的表现与模式其实正是不同文化之间的差异造成的。     

A macro-level analysis of SRL processes and their relations to the acquisition of a sophisticated mental model of a complex system

In this study, we used think-aloud verbal protocols to examine how various macro-level processes of self-regulated learning (SRL; e.g., planning, monitoring, strategy use, handling of task difficulty and demands) were associated with the acquisition of a sophisticated mental model of a complex biological system. Numerous studies examine how specific micro-level SRL processes such as judgments of learning or prior knowledge activation are related to learning outcomes. However, it is also valuable to look at these processes in macro-level aggregates because efficacy and use of micro-level strategies can vary due to individual differences. Two hundred and nineteen high-school and middle-school students produced think-aloud protocols while learning with a hypermedia environment. We transcribed and coded participants’ learning sessions for the use of micro- and macro-level SRL processes. Participants’ developmental level, prior knowledge, and monitoring behaviors were associated with posttest mental model sophistication. These results illustrate that monitoring is a key SRL process when developing an understanding of a complex science topic using hypermedia.     

从钱玄同看近代中国汉字改革

中国近代汉字改革与钱玄同有着重要的关系,他是"五四"时期的国语罗马字运动及简化字运动的主要推动者之一.中国近代的汉字改革有着特定的历史背景和政治因素,今天我们有必要对其进行反思.     

Students’ Learning with the Connected Chemistry (CC1) Curriculum: Navigating the Complexities of the Particulate World

The focus of this study is students’ learning with a Connected Chemistry unit, CC1 (denotes Connected Chemistry, chapter 1), a computer-based environment for learning the topics of gas laws and kinetic molecular theory in chemistry (Levy and Wilensky 2009). An investigation was conducted into high-school students’ learning with Connected Chemistry, based on a conceptual framework that highlights several forms of access to understanding the system (submicro, macro, mathematical, experiential) and bidirectional transitions among these forms, anchored at the common and experienced level, the macro-level. Results show a strong effect size for embedded assessment and a medium effect size regarding pre-post-test questionnaires. Stronger effects are seen for understanding the submicroscopic level and bridging between it and the macroscopic level. More than half the students succeeded in constructing the equations describing the gas laws. Significant shifts were found in students’ epistemologies of models: understanding models as representations rather than replicas of reality and as providing multiple perspectives. Students’ learning is discussed with respect to the conceptual framework and the benefits of assessment of learning using a fine-tuned profile and further directions for research are proposed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

基于Struts、Spring与Hibernate框架的科研信息管理查询系统的实现

基于Struts,Spring和Hibernate的科研信息管理查询系统是集科研信息查询、汇总、图表显示为一体的系统,对于单一框架中查询应用结构复杂、扩展性差的问题给出了解决的实例。