The role of situation assessment and flight experience in pilots' decisions to continue visual flight rules flight into adverse weather

Visual flight rules (VFR) flight into instrument meteorological conditions (IMC) is a major safety hazard in general aviation. In this study we examined pilots' decisions to continue or divert from a VFR flight into IMC during a dynamic simulation of a cross-country flight. Pilots encountered IMC either early or later into the flight, and the amount of time and distance pilots flew into the adverse weather prior to diverting was recorded. Results revealed that pilots who encountered the deteriorating weather earlier in the flight flew longer into the weather prior to diverting and had more optimistic estimates of weather conditions than did pilots who encountered the deteriorating weather later in the flight. Both the time and distance traveled into the weather prior to diverting were negatively correlated with pilots' previous flight experience. These findings suggest that VFR flight into IMC may be attributable, at least in part, to poor situation assessment and experience rather than to motivational judgment that induces risk-taking behavior as more time and effort are invested in a flight. Actual or potential applications of this research include the design of interventions that focus on improving weather evaluation skills in addition to addressing risk-taking attitudes.     

Age differences in perceived workload across a short vigil

The main objective of this research was to investigate age differences in the perceived workload associated with the performance of a demanding, high event rate, vigilance task. Younger participants (n=26) aged 16 to 35 years (M=27.8) and older participants (n=24) aged 45 to 65 years (M=52.2) completed perceived workload scales (NASA-TLX) following a brief practice session (pretest) on the vigilance task, and then again following a test session (posttest) lasting nine minutes. In relation to the vigilance task, a statistically significant performance decrement was identified, but there was no evidence that performance differed according to age in respect to that decrement. However, a dissociation was found in relation to the perceived workload ratings: while no age differences were found in vigilance performance, the workload ratings revealed older participants to perceive a significantly greater increase in workload from pretest to posttest. These findings are considered theoretically in relation to the demands placed upon attentional resources, and their implications for both laboratory-based vigilance research, and workplace systems monitoring situations, are discussed.     

Learning nonregular languages: a comparison of simple recurrent networks and LSTM

In response to Rodriguez's recent article (2001), we compare the performance of simple recurrent nets and long short-term memory recurrent nets on context-free and context-sensitive languages.     

NAVSTAR全球定位系统卫星空间环境的设计要求和方案的发展

NAVSTAR全球定位系统（GPS）卫星星座为美国军队和各商业用户提供全球导航支持。已经设计了两代卫星（Ⅰ批和Ⅱ／Ⅱ-A批）并投入了使用，第3代（Ⅱ-R批）已经准备发射，第4代（Ⅱ—F批）正在生产组装。从第一次发射开始，在技术先进性和轨道实验方面就着重于改善以后发射的卫星的设计要求和设计方案。考虑了那些直接与具体的空间环境有关的要求，并注意它们对提出的定位设计方案的影响。可以看到针对光化学污染、航天器带电和辐射衰减的轨道实验使得设计更灵活，并使其具有更长的寿命和更强的功能。     

应对变革24准则

企业如果不随着市场的发展变革,就会逐步走向衰败——这是企业经营的基本事实。但是,与企业的生死存亡紧密相关的变革,不可避免地会给员工带来诸如不安定、压力甚至是愤怒和抵触的情绪。那么,怎样帮助企业经理和员工理解变革、适应变革、参与变革,并在新的环境和新的职责中取得成就呢?该书以精炼的篇幅将企业组织中的变革管理技巧整理成24个关键点,并详细阐述了成功应对变革的各种实用策略,如合理利用资源来帮助员工,学会适应不确定性;为新业务制定新的运作章程;公开相关信息,避免谣言的产生等。该书力图让处于变革中的企业领导和员工在贯彻…     

隔爆型设备的新型材料--为安全避免火焰传播,采用多孔材料

用于危险场所的电气设备和保护系统按指令94／9／EC要求，必须设计为防爆型。按防爆要求，设备或保护系统，无论是在正常运行时或故障状态下，不能成为点燃源。在防爆技术发展的进程中，研究出了各种各样的保护方式，这些保护方式在欧洲协调标准中都有相应的规定。在一些保护方式中，如浇封型“m”，充砂型“q”，正压型“p”和油浸型“o”，采用适当的设计方法(保护措施)可以阻止可能产生点燃源的电气装置的部件与爆炸性环境接触；在增安型“e”和本安型“i”中，     

籼型杂交水稻保持系IR58025B pin2转基因植株

杂交水稻技术在中国及其他国家已作为发展水稻生产,满足不断增加的人口对粮食需要的一条关键途径．而另一方面,据估计因螟虫危害造成水稻年均损失为5％～10％,有时高达60％～95％．应用马铃薯蛋白酶抑制剂基因(potato proteinase inhibitor Ⅱor pin2)进行粳稻的遗传转化实验表明,其转基因粳稻植株对螟虫的抗性显著提高,且该转基因能在后代中稳定遗传(Duan et al．,1996)．为了改良杂交水稻对螟虫的抗性,以大面积应用的籼型杂交稻保持系IR58025B成熟胚为外植体材料、以pin为目的基因、通过基因枪法高效获得了大量转基因植株．PCR检测结果表明转基因pin2成功地整合于植株基因组中．三化螟幼虫饲喂试验结果初步证实了该转基因在转基因当代植株中的表达．     

Ba1-xLaxTiO3陶瓷的晶界再氧化机理研究

不同La施主掺杂浓度的BaTiO3陶瓷在H2／Ar的还原气氛下烧结后，再在氧分压PO2=260Pa的气氛（Ar和O2的混合气体）下进行氧化，通过氧流量计检测还原样品在再氧化过程的吸氧行为；用TEM分析样品氧化后显微结构的变化，测定了在不同最高氧化温度下氧化样品的PTCR效应以及复阻抗图谱．结果表明；氧流量计在升温阶段检测到三个不同行为的吸氧峰，峰Ⅰ（起始温度-250℃）为氧空位的填充过程；峰Ⅱ（起始温度-800℃）和峰Ⅲ（起始温度-1250℃）为还原相的氧化过程，具体来说，峰Ⅱ是通过晶界扩散提供氧使靠近晶界附近的区域被氧化；而峰Ⅲ是由晶格扩散过程控制，氧化过程从晶界逐渐向晶粒内部区域扩展，并伴随着富Ti的Ba6Ti17O40相的沉淀．在还原相向氧化相的转变过程中，于晶界处形成了两个具有晶界势牟的电结构单元而使陶瓷旱现强PTCR效应．     

真空灭弧室 配电开关 断路器和接触器的高可靠性元件

自从20世纪50年代中期将真空灭弧室(VI)用作配电操作开关、断路器和接触器的电流分断元件以来,其作用逐步增强.在电路的开断和配电保护领域,该电气产品已经占统治地位.真空灭弧室甚至被引入到电力输送中的通断产品的领域上.真空灭弧室受到追捧的原因有:结构紧凑、适用范围广、成本低、极好的电寿命和机械寿命,以及使用方便.其中,最重要的优点是公认的高可靠性.