Optimal linear quadratic Gaussian control for discrete time-varying system with simultaneous input delay and state/control-dependent noises

This article focuses on the problem of linear quadratic Gaussian (LQG) control for discrete time-varying system with input delay and state/control-dependent noises. When the state variables can be exactly observed, first, we obtain the maximum principle by applying the method of variation. Second, a nonhomogeneous relationship between the state and the costate is developed in virtue of the obtained maximum principle and the mathematical induction. It is noted that the nonhomogeneous relationship is the solution to the forward and backward stochastic difference equations (FBSDEs). Finally, based on the solution to the FBSDEs, a necessary and sufficient condition for the optimal LQG control is derived in terms of coupled Riccati equations. Moreover, the analytical expression of the optimal controller is presented. The derived results are applied in networked control systems with packet dropout. Numerical examples are shown to illustrate the effectiveness of the proposed algorithm.     

新型氧气湿化输送系统的研制与临床应用

目的保证氧疗效果,解决氧气湿化过程中普遍存在的湿化液污染及湿化产生噪声问题。方法将172例需吸氧的肺癌患者随机分为观察组和对照组各86例,观察组应用自行研制的新型氧气湿化输送系统吸氧,对照组使用传统氧气湿化输送系统吸氧。结果观察组仅1例患者主观感受到湿化噪声,与对照组比较,差异有统计学意义（P〈0．01）;观察组湿化单元细菌培养阳性率显著低于对照组（P〈0．01）。结论新型氧气湿化输送系统应用于临床氧疗,能降低传统氧气湿化液污染导致的医院呼吸道感染的风险,降低噪声,可保证患者休息,且不影响氧疗效果。     

健听人在不同本底噪声环境中的听阈值分析

目的计算健听人在不同本底噪声环境中的听阈值,通过与在标准测听环境中的结果相比较,确定非标准测听环境中听阈的修正值,探讨听力残疾抽样调查中最低环境本底噪声级的控制值。方法在不同的本底噪声环境中,采用纯音测试和声场测试的方法,对50人(100耳)分别进行测听。结果研究结果显示,在本底噪声分别为45dB(A)、50dB(A)、55dB(A)的测听环境中,健听者的纯音测试听阈值分别为15dBHL、20dBHL、25dBHL,与标准测听环境中的听阈差值分别为10dBHL、15dBHL、20dBHL;声场测试听阈值分别为25dBHL、30dBHL、35dBHL,与标准测听环境中的听阈差值分别为15dBHL、20dBHL、25dBHL;统计结果显示,不同本底噪声环境中,健听人的听阈值具有显著性差异。结论根据健听人在不同本底噪声环境中与在标准测听环境中的听阈差值,可以确定在非标准测听室及相应本底噪声环境中的听阈修正值,也可以确定听力残疾评定允许测听环境最高噪声级。     

The role of silent intervals for sentence intelligibility in fluctuating noise in hearing-impaired listeners

Fluctuating interfering noises are highly suitable for speech audiometry because of the large inter-individual variability in intelligibility results. This study explores the maximum duration of silent intervals in the masker as an important factor underlying sentence intelligibility in fluctuating noise. Three versions of speech-simulating fluctuating interfering noises based on the icra noises (Dreschler et al, ) were explored: The original noise which simulates one interfering speaker and contains pause durations up to two seconds, as well as two modified versions with pause durations limited to 250?ms and 62.5?ms, respectively. In addition, a stationary speech-shaped noise was used. Test-retest reliability as well as speech reception threshold (SRT) and speech intelligibility function slope were determined with hearing-impaired subjects. All fluctuating noises differentiated very well between subjects. Partial rank correlation analysis showed that SRTs in fluctuating noise with longest maximum pause durations mostly depended on SRTs in quiet. SRTs in fluctuating noises with smaller maximum pause durations correlated both with SRTs in quiet and in stationary noise.

Sumario

Los ruidos fluctuantes de interferencia son muy apropiados en logoaudiometría debido a la gran variabilidad inter-individuos en los resultados de inteligibilidad. Este estudio explora la duración máxima de intervalos de silencio en el enmascarador, como un importante factor subyacente en la inteligibilidad de frases en medio de ruido fluctuante. Se exploraron tres versiones de ruidos fluctuantes de interferencia simulando lenguaje, con base en los ruidos icra (Dreschler y col., 2001): el ruido original que simula la interferencia de un hablante y contiene pausas de hasta 2 segundos de duración, y también dos versiones modificadas con pausas de duración limitadas a 250 mseg y 62.5 mseg, respectivamente. Además, se utilizó un ruido estacionario moldeado como lenguaje. Se determinó la confiabilidad test-retest al igual que la pendiente de las funciones del SRT y la inteligibilidad del lenguaje, en sujetos hipoacúsicos. Todos los ruidos fluctuantes se diferenciaron muy bien entre los sujetos. Un análisis de correlación de rango parcial mostró que los SRT en ruido fluctuante con las duraciones más prolongadas de pausa máxima, dependían del SRT en silencio. Los SRT en ruido fluctuante con duraciones menores de pausa máxima, correlacionaron tanto con los SRT en silencio como con el ruido estacionario.     

对接触高温噪声的轧钢工人心电图分析

[目的]了解高温噪声对作业工人心电图的影响.[方法]选择接触高温噪声的轧钢工人546名和低噪声常温作业的机械修理工、电工512名为对照组,进行心电图检查,其数据进行统计学处理分析.[结果]轧钢工心电图异常率为33.7%,对照组组为20.5%两组差异有非常显著性(x2=23.16,P＜0.01);轧钢工人心电图异常发生率与工龄呈正相关(r=0.97).[结论]应降低轧钢工作环境的噪声和加强防暑降温以减少对作业工人的职业危害.     

颞下颌关节紊乱病的“梯度序列治疗”

颞下颌关节紊乱病是口腔科临床常见的疾病,好发于青年群体,女性多见,发病率在30%左右;其临床表现多为下颌运动异常、疼痛、弹响与杂音,部分患者伴有耳鸣、头痛等症状。颞下颌关节紊乱病的治疗目前主张采用"梯度序列治疗"模式,每个"层级"均有其严格的适应证。一般首选保守治疗或无创治疗,适用于功能障碍性或轻度器质性病变患者;次选微创治疗,适用于保守治疗无效患者或轻度器质性病变患者;最后才考虑选择开放手术治疗,适用于前两种治疗无效并伴有严重器质性病变的患者。"梯度序列治疗"方案的制定应该是个性化的,由医生主导,患者配合的情况下完成的。本文对颞下颌关节紊乱病的"梯度序列治疗"进行阐述。     

Cochlear Distribution of Frequency-Following Response Initiation: A High-Pass Masking Noise Study

The cochlear initiation of the frequency-following response (FFR) to 500-Hz tone bursts was assessed in 6 normal-hearing subjects by measuring FFR amplitude as a function of the low-frequency cutoff of high-pass masking noise (3 550, 1 800, 900, and 450 Hz). The major fall off of FFR amplitude occurred when the masking noise began to mask the apical portion of the cochlea. This effect was especially apparent at low intensities. The results are interpreted as supporting the view that at low intensities, low-frequency tone bursts evoke the FFR primarily through the apical portion of the cochlea.

Dans cette expéerimentation nous avons utilisé un bruit de masquage filtré passe-haut (la fréquence de coupure étant 3 550, 1 800, 900 ou 450 Hz) pour déterminer, en fonction de la hauteur de la fréquence de coupure, l'amplitude de la réeponse suivant la fréquence (FFR) à des «tone-bursts» de 500 Hz. La plus grande diminution de l'amplitude de la FFR débute lorsque le masquage commence à atteindre la portion apicale de la cochlée; cet effet est particulièrement net pour les intensités faibles. Ceci confirme notre opinion, à savoir que des tone-bursts de faible intensite évoquent des FFR essentiellement à partir de la portion apicale de la cochlée.     

基于小波变换的医学图像去噪声处理

利用中值滤波和基于小波变换的去噪声处理对同时含有高斯噪声和脉冲噪声的X线图像降噪方法进行探讨.采用PSNR评价标准分析实验结果,表明小波变换结合中值滤波方法在去除噪声的同时较好地保持了原图像所包含的边缘信息,处理效果优于单纯的小波变换或单纯的中值滤波.     

扩展高频测听对耳鸣及噪音性聋患者早期听力损害的诊断作用

目的探讨扩展高频测听对耳鸣及噪音性聋患者早期听力损害的诊断意义。方法应用扩展高频测听对常规纯音测听测试正常的耳鸣及噪音暴露者和正常对照组进行检测。结果随着测试频率增高，耳鸣组与噪音组患者的听阈逐渐增加，而听阈检出率逐渐下降，与对照组相比差异有显著性意义。结论扩展高频测听可以作为耳鸣及噪音性聋患者早期听力损害的诊断依据。     

吸氧病人的舒适护理

[目的 ]提高吸氧病人的舒适度。 [方法 ]选择符合条件的长期吸氧病人 ,随机分为实验组及对照组 ,分别给予舒适吸氧法及常规吸氧法 ,并进行吸氧舒适度调查。 [结果 ]两组病人对吸氧的舒适度存在差异 (P <0 .0 1)。[结论 ]舒适吸氧法可提高病人吸氧的舒适度