Passivity-Based Robust Control Against Quantified False Data Injection Attacks in Cyber-Physical Systems

Secure control against cyber attacks becomes increasingly significant in cyber-physical systems(CPSs).False data injection attacks are a class of cyber attacks that aim to compromise CPS functions by injecting false data such as sensor measurements and control signals.For quantified false data injection attacks,this paper establishes an effective defense framework from the energy conversion perspective.Then,we design an energy controller to dynamically adjust the system energy changes caused by unknown attacks.The designed energy controller stabilizes the attacked CPSs and ensures the dynamic performance of the system by adjusting the amount of damping injection.Moreover,with the disturbance attenuation technique,the burden of control system design is simplified because there is no need to design an attack observer.In addition,this secure control method is simple to implement because it avoids complicated mathematical operations.The effectiveness of our control method is demonstrated through an industrial CPS that controls a permanent magnet synchronous motor.

Adaptive Excitation Control with L_2 Disturbance Attenuation for Multi-Machine Power Systems

Generator excitation control plays an important role in improving the dynamic performance and stability of power systems. This paper is concerned with nonlinear decentralized adaptive excitation control for multi-machine power systems. Based on a recursive design method, an adaptive excitation control law with L2 disturbance attenuation is constructed. Furthermore, it is verified that the proposed control scheme possesses the property of decentralization and the robustness in the sense of L2-gain. As a consequence, transient stability of a multi-machine power system is guaranteed, regardless of system parameters variation and faults.

氯胺酮复合乌司他丁对大鼠内毒素性急性肺损伤的影响

目的 探讨氯胺酮复合乌司他丁对大鼠内毒素性急性肺损伤（acute lung injury, ALI）的影响。方法 成年雄性SD大鼠100只，体重280 g ~ 320 g，采用计算机简单随机分组法随机分为5组（每组20只）：对照组（C组）、内毒素组（L组）、氯胺酮组（K组）、乌斯他丁组（U组）、氯胺酮复合乌斯他丁组（K＋U组）。除C组外，其余大鼠腹腔注射0.03 %脂多糖（lipopolysaccharide, LPS）1 mg/kg，注射后16 h时，由尾静脉再次注射0.l % LPS 1.5 mg/kg，建立大鼠ALI 模型。U组、K＋U组分别在第2次注射LPS后经尾静脉注射乌司他丁 50 000 U/kg，注射乌司他丁后即刻，K 组、K＋U 组经尾静脉以微量泵持续输注氯胺酮 10 ㎎？㎏-1？h-1，其余组注射等容量生理盐水。于第2次注射 LPS 后1、2、3、4 h （T1~4）时，各组取5只大鼠，抽取腹主动脉血样0.5 ml，测定氧分压（PaO2），抽取下腔静脉血样2 ml，测定血清肿瘤坏死因子（tumor necrosis factor，TNF）-α和白介素（interleukin，IL）-6浓度；放血处死大鼠，取右肺上叶组织，光镜下观察肺组织病理学结果，进行肺组织病理半定量评分及测定核因子（nuclear factor-κB, NF-κB）抑制蛋白α （inhibitor of nuclear factor-κBα, IκBα）表达；取右肺中叶组织100 mg测定肺组织NF-κB活性；取右肺下叶组织，计算肺湿干重比（W/D）。结果 与C组比较，L组、K组、U组和K＋U组PaO2降低，血清TNF-α、IL-6浓度和肺组织NF-κB活性升高，IκBα表达降低， W/D升高（P〈0.01）；与L组比较，K组、U组和K＋U组PaO2升高，血清TNF-α、IL-6浓度和肺组织NF-κB活性降低，IκBα表达升高，W/D降低，肺组织病理评分降低 （P〈0.05或0.01）；与K组和U组比较，K＋U组各时点PaO2升高，血清TNF-α、IL-6浓度和肺组织NF-κB活性（2.49±0.23）降低，IκBα表达（35.1±3.4）升高，W/D（4.91±0.16）降低，肺组织病理评分（7.8±0.8）降低（P〈0.05或0.01） 。结论 氯胺酮复合乌司他丁可减轻大鼠ALI，较两者单独应用效果显著。