Detection of replay attacks in cyber-physical systems using a frequency-based signature

This paper proposes a frequency-based approach for the detection of replay attacks affecting cyber-physical systems (CPS). In particular, the method employs a sinusoidal signal with a time-varying frequency (authentication signal) into the closed-loop system and checks whether the time profile of the frequency components in the output signal are compatible with the authentication signal or not. In order to carry out this target, the couplings between inputs and outputs are eliminated using a dynamic decoupling technique based on vector fitting. In this way, a signature introduced on a specific input channel will affect only the output that is selected to be associated with that input, which is a property that can be exploited to determine which channels are being affected. A bank of band-pass filters is used to generate signals whose energies can be compared to reconstruct an estimation of the time-varying frequency profile. By matching the known frequency profile with its estimation, the detector can provide the information about whether a replay attack is being carried out or not. The design of the signal generator and the detector are thoroughly discussed, and an example based on a quadruple-tank process is used to show the application and effectiveness of the proposed method.     

Orthogonal functions approach to optimal control of delay systems with reverse time terms

Using block-pulse functions (BPFs)/shifted Legendre polynomials (SLPs) a unified approach for computing optimal control law of linear time-varying time-delay systems with reverse time terms and quadratic performance index is discussed in this paper. The governing delay-differential equations of dynamical systems are converted into linear algebraic equations by using operational matrices of orthogonal functions (BPFs and SLPs). The problem of finding optimal control law is thus reduced to the problem of solving algebraic equations. One example is included to demonstrate the applicability of the proposed approach.     

Decentralized optimal controller design for multimachine power systems using successive approximation approach

In this paper, we propose to develop algorithmically and implement a nonlinear decentralized optimal control for multimachine power systems, based on a successive approximation approach for designing the optimal controller with respect to quadratic performance index. The advantage of this approach is to transform the high order coupling nonlinear two-point boundary value (TPBV) problem into a sequence of linear decoupling TPBV problem, which uniformly converges to the optimal control for nonlinear interconnected large scale systems. We apply this approach to a 3-machine power system which generators are strongly nonlinear interconnected, and containing possible uncertainties on the parameters. We demonstrate clearly via advanced simulations that this approach brings better performances than other decentralized controller, improving effectively transient stability of these power systems in few iterative sequences for different cases of perturbations.     

Quadratic stability analysis and robust distributed controllers design for uncertain spatially interconnected systems

This paper is concerned with the quadratic stability analysis and robust distributed controllers design of both continuous-time and discrete-time uncertain spatially interconnected systems (USISs), where uncertainties are modeled by linear fractional transformation (LFT). The well-posedness, quadratic stability, and contractiveness of USISs are properly defined for the first time. A sufficient condition employing the given system matrices is established to check the well-posedness, quadratic stability and contractiveness. This condition is simpler than the existing conditions based on the decomposition of system matrices. Based on the new condition derived, a sufficient condition is given for the existence of robust distributed controllers and a constructive method is then presented for the design of robust distributed controllers. The advantage of the proposed constructive approach is that it employs the given system matrices while the existing methods conduct the bilinear transformation on these matrices when design controllers, and consequently, the constructive approach in this paper is computationally more efficient than the existing methods. Several examples are included to demonstrate the simplicity, efficiency and applicability of the derived theoretical results.     

Stability of Markov jump systems with quadratic terms and its application to RLC circuits

The paper presents results for the second moment stability of continuous-time Markov jump systems with quadratic terms, aiming for engineering applications. Quadratic terms stem from physical constraints in applications, as in electronic circuits based on resistor (R), inductor (L), and capacitor (C). In the paper, an RLC circuit supplied a load driven by jumps produced by a Markov chain—the RLC circuit used sensors that measured the quadratic of electrical currents and voltages. Our result was then used to design a stabilizing controller for the RLC circuit with measurements based on that quadratic terms. The experimental data confirm the usefulness of our approach.     

Finite-time stabilization of nonlinear time delay systems using LQR based sliding mode control

In this paper, we discussed the robust finite-time stability of conic type nonlinear systems with time varying delays. Some novel conditions are derived to design a linear quadratic regulator (LQR) based sliding mode control (SMC) by proposing an integral switching surface. The sufficient conditions are derived for the considered nonlinear system using Lyapunov–Krasovskii stability theory and linear matrix inequality (LMI) approach. The proposed conditions can be solved using some standard numerical packages. Finally, a practical example is provided to validate the advantages and effectiveness of the proposed results.     

新能源汽车推广应用的“非补贴型”政策作用及其差异

在新能源汽车“补贴型”政策逐步“退坡”的背景下,有效发挥“非补贴型”政策的作用具有重要的现实意义。选择中国目前实施的“路权优先”和“充电保障”两项主要“非补贴型”政策,以新能源汽车示范推广城市为例,应用双重差分模型从时间和区域两个维度分析了两项“非补贴型”政策作用的差异性。结果表明：从时间维度来看,新能源汽车“非补贴型”政策作用虽然稍低于“补贴型”政策,但是十分显著并呈现持续上升趋势,新能源汽车“非补贴型”政策可以成为“补贴退坡”后市场持续发展的重要政策支撑,其中,“路权优先”政策作用的增幅相对更大;从区域维度来看,“充电保障”政策作用的区域差异不明显,“路权优先”政策作用则存在比较明显的区域差异性,城市的交通承载压力越高,“路权优先”政策作用越强。在新能源汽车“补贴退坡”的情形下,应在快速推进充电桩等基础设施布局的同时,加大新能源汽车“路权优先”政策实施的力度,同时,要根据交通承载压力的区域差异性,因地制宜地实施差异化的“非补贴型”政策。     

On stability and stabilization of singular uncertain Takagi–Sugeno fuzzy systems

This paper deals with the problem of robust stability and robust stabilization for a class of continuous-time singular Takagi–Sugeno fuzzy systems. Sufficient conditions on stability and stabilization are proposed in terms of strict LMI (Linear Matrix Inequality) for uncertain T–S fuzzy models. In order to reduce the conservatism of results developed using quadratic method, an approach based on non-quadratic Lyapunov functions and S-procedure is proposed. Illustrative examples are given to show the effectiveness of the given results.     

转型背景下企业EBMI与ETI的适配模式研究

本文以山西省传统资源型制造企业为研究载体,从创新生态化视角,通过理论分析,提出了不同生命周期阶段企业的商业模式创新生态化（EBMI）与技术创新生态化（ETI）的匹配模式研究假设。运用匹配测度模型与GE矩阵分析相结合的方法,选取239家企业为样本数据,对假设进行了检验和讨论,结果显示：初创期或蜕变期,企业表现出新颖型EBMI与探索型ETI的最佳匹配模式;成长期表现出效率型EBMI与利用型ETI的最佳匹配模式;成熟期表现出系统型EBMI与双元型ETI的最佳匹配模式。该研究为企业在不同时期开展生态价值与经济价值协同创造的创新活动中,选择合适的创新生态化匹配模式,促进企业转型提供一定的理论参考。     

Biochemical Effects of Lead Exposure on Battery Manufacture Workers with Reference to Blood Pressure, Calcium Metabolism and Bone Mineral Density

Lead is one of the most widely scattered toxic metals in the environment and used by mankind for over 9,000 years. Lead in the environment may be derived from natural or anthropogenic sources. In humans, lead can cause a wide range of biological effects depending upon the level and duration of exposure. The purpose of this study was to find out the effect of lead exposure on systolic and diastolic blood pressure, serum calcium, ionized calcium, phosphorus, parathyroid hormone and vitamin D and examine the overall effect of all these parameters on the bone mineral density of battery manufacture workers. For this study ninety battery manufacture workers were selected and divided in three groups depending upon duration of lead exposure. Group I—workers with duration of lead exposure 1–5 years, Group II—workers with duration of lead exposure 6–10 years and Group III—workers with duration of lead exposure more than 10 years. Each group consisted of thirty workers. Thirty age matched healthy control subjects were taken for comparison. Demographic, occupational and clinical data were collected by using questionnaire and interview. The venous blood samples were collected from the study groups and normal healthy control group. At the time of blood collection random urine samples were collected in amber coloured bottles. The biochemical parameters were estimated by using standard assay procedures. Statistical analysis of the data was done using independent student‘t’ test for parametric variables. Values were expressed as mean ± standard deviation (SD). P values of 0.05 or less were considered to be statistically significant. The blood lead levels and urinary lead levels of all workers were significantly increased (P < 0.001) in proportion to the duration of lead exposure as compared to controls. Systolic and diastolic blood pressure were significantly raised (P < 0.001) in all three study groups of battery manufacture workers as compared to controls. Serum Calcium, Ionized calcium, phosphorus were significantly decreased (P < 0.001) in all the three study groups. Serum vitamin D levels were lowered (P < 0.01) and serum PTH was increased (P < 0.01) in workers as compared to controls. The results of this study clearly indicate that the absorption of lead is more in these workers which adversely affects blood pressure, disturbs calcium and phosphorus metabolism which further impairs mineralization of bone resulting in decreased bone mineral density observed in these workers. Lead toxicity is still persistent in battery manufacture workers though they are using sophisticated techniques in these industries. There is a need to protect the workers from the health hazards of occupational lead exposure.     

A Case of Sanfillippo’s Disease Correlating Clinical and Biochemical Findings

The mucopolysaccharidoses (MPSs) are a heterogeneous group of rare inherited disorders caused by deficiency of lysosomal enzyme necessary to break down mucopolysaccharides or glycosaminoglycans (GAGs). We had combined clinical findings and ophthalmological features. Biochemical test for urine glycosaminoglycans was done for confirmation of diagnosis in the patient. The case of Sanfillippo’s disease was characterized by delayed development, hyperactivity with aggressive behaviour. Coarse facial feature, hirsutism and sleep disorder. Urine GAG tests for MPS was positive in the case. Based on clinical findings and biochemical tests for MPS, this case was diagnosed as a type III mucopolysaccharidoses. Urinary GAG’s electrophoresis is an important screening test for MPS suspected cases.     

VDR,RXR, Coronin-1 and Interferonγ Levels in PBMCs of Type-2 Diabetes Patients: Molecular Link between Diabetes and Tuberculosis

Diabetes and tuberculosis are world’s most deadly epidemics. People suffering from diabetes are susceptible to tuberculosis. Molecular link between the two is largely unknown. It is known that Vitamin A receptor (RXR) heterodimerizes with Vitamin D receptor (VDR) and Peroxisome proliferator-activator receptor-γ (PPARγ) to regulate Tryptophan-aspartate containing coat protein (TACO) expression and fatty acid metabolism respectively, so it would be interesting to check the expression of these genes in diabetes mellitus (DM) patients which might explain the susceptibility of diabetics to tuberculosis. In this study, we checked the expression of RXR, VDR, TACO and Interferon-γ (IFNγ) genes in type-2 DM patients for understanding the link between the two diseases. We observed down regulation of RXR gene and corresponding up regulation of TACO gene expression. We have not observed significant change in expression of VDR and IFNγ genes in type-2 DM patients. Repression of RXR gene could hamper VDR-RXR heterodimer formation and thus would up regulate TACO gene expression which may predispose the type-2 DM patients to tuberculosis. Also, decrease in RXR-PPARγ heterodimer could be involved in DM.     

New results on linear parameter-varying time-delay systems

A class of linear parameter-varying time-delay systems where the state-space matrices depend on time-varying parameters and the time-delay is unknown but bounded is considered. Both notions of quadratic stability (using a single quadratic Lyapunov-Krasovskii function) and affine quadratic stability (using parameter-dependent Lyapunov-Krasovskii functions) are investigated. LMI-based delay-independent and delay-dependent conditions are derived for stability testing. Then, state-feedback controllers are designed which guarantee quadratic stability and an induced L₂-norm bound. We use a parameter-independent quadratic Lyapunov-Krasovskii function for the case of dynamic output feedback control to develop LMI-based solvability conditions which are evaluated at the extreme points of the admissible parameter set. Numerical examples are presented.     

自然指数和基本科学指标在基础研究领域影响力的差异化分析

在学科水平评估中引入基本科学指标(ESI)、自然指数(NI)等指标直接影响到我国世界一流大学、一流学科的建设效果。通过统一数据统计口径,从国家/地区、科研机构/大学、学科领域等角度比较分析ESI和NI指标的差异,根据统计结果分析两者对我国基础研究的导向,并提出相应的对策和建议。     

Generalized filtering of one-sided Lipschitz nonlinear systems under measurement delays

This paper addresses the filtering problem for the one-sided Lipschitz nonlinear systems under measurement delays and disturbances using a generalized observer. A generalized architecture for filtering of the one-sided Lipschitz nonlinear systems with output delays is explored, which exhibits diverging manifolds, namely, the conventional static-gain filter and the dynamical filter, and can be employed to render robust stability of the filtering error dynamics. A matrix inequality based framework is obtained by employing a Lyapunov?Krasovskii (LK) functional, whose derivative is exploited through Jensen's inequality, one-sided Lipschitz condition, quadratic inner-boundedness inequality and range of the measurement delay, resulting into L₂ stability for the filtering error system. Generalized filter design for the Lipschitz nonlinear systems with delayed outputs and specific results for the delay-dependent and delay-rate-independent filtering schemes for the one-sided Lipschitz nonlinear systems are deduced from the proposed approach. Convex optimization techniques are employed to achieve a solution for the nonlinear constraints through linear matrix inequalities by employing cone complementary linearization approach. Illustrative numerical examples to demonstrate the effectiveness of proposed method are provided.     

Red blood cell membrane-camouflaged nanoparticles loaded with AIEgen and Poly(I : C) for enhanced tumoral photodynamic-immunotherapy

Red blood cell (RBC)-mimicking nanoparticles (NPs) offer a promising platform for drug delivery because of their prolonged circulation time, reduced immunogenicity and specific targeting ability. Herein, we report the design and preparation of RBC membrane-bound NPs (M@AP), for tumoral photodynamic-immunotherapy. The M@AP is formed by self-assembly of the positively charged aggregation-induced emission luminogen (AIEgen) (named P2-PPh3) and the negatively charged polyinosinic : polycytidylic acid (Poly(I : C)), followed by RBC membrane encapsulation. P2-PPh3 is an AIE-active conjugated polyelectrolyte with additional photosensitizing ability for photodynamic therapy (PDT), while Poly(I : C) serves as an immune-stimulant to stimulate both tumor and immune cells to activate immunity, and thus reduces tumor cell viability. When applied in tumor-bearing mice, the M@AP NPs are enriched in both the tumor region as a result of an enhanced permeability and retention (EPR) effect, and the spleen because of the homing effect of the RBC-mimicking shell. Upon light irradiation, P2-PPh3 promotes strong ROS generation in tumor cells, inducing the release of tumor antigens (TA). The anti-tumor immunity is further enhanced by the presence of Poly(I : C) in M@AP. Thus, this strategy combines the PDT properties of the AIE-active polyelectrolyte and immunotherapy properties of Poly(I : C) to achieve synergistic activation of the immune system for anti-tumor activity, providing a novel strategy for tumor treatment.     

碳交易机制与企业绿色创新：基于三重差分模型

    低碳经济与绿色发展密切相关,目前关于碳交易机制对企业绿色创新影响的分析缺乏微观企业层面的经验证据。本文基于2009—2016年间中国沪深两市A股上市公司的专利数据,以2013年末在7个省市开展的碳排放权交易试点作为准自然实验,采用三重差分的估计方法,通过对比碳交易试点政策实施前后、试点省市相对于非试点省市、高污染行业相对于低污染行业的企业绿色专利申请占比的变化情况,探究碳交易机制政策对企业绿色创新活动的影响,并进行了一系列异质性讨论和稳健性检验。实证结果表明：（1）相对于非试点省市和试点省市的低污染行业,碳交易试点政策能够提高试点省市高污染行业的企业的绿色专利申请比例。（2）相比于发明类绿色专利,该政策对绿色专利中的非发明类专利的促进作用更强。（3）相对于国有企业,该政策对试点省市上市公司中非国有企业的绿色创新的激励作用更加显著。此外,本文发现：碳排放权交易试点政策能够增加高污染行业企业的科研人才引进和提高科技研发支出、提高企业资产净利润率,进而直接或间接地促进了企业绿色创新发展。本文的研究结论能够为中国实施全国碳排放权交易政策提供一定经验支持;为如何实现提质增效、更好促进企业节能降耗和绿色发展提供政策建议。     

数字经济、区域软环境与技术转移网络的形成

数字经济通过压缩信息传递时空距离,增强了区域间技术转移活动的深度与广度。利用专利转让数据构建区域技术转移网络,结合模体分析揭示区域技术转移网络的局部结构特征,并通过指数随机图模型（ERGM）探究数字经济、区域软环境对技术转移网络形成的影响。研究发现：区域技术转移网络呈现出强互惠性、弱传递性的特征;数字经济发展推动区域技术转移向纵深发展,但数字经济发展差异导致技术转移网络中存在“富人俱乐部”特性与“技术孤岛”困境,将进一步加深区域间技术鸿沟;区域软环境因素中,法制环境、技术环境、政府治理环境、金融环境均对技术转移产生不同程度的正向促进作用,市场环境正向调节数字经济对技术转移的影响。据此为推动区域技术转移高质量发展提供有益启示。     

TS fuzzy robust L1 control for nonlinear systems with persistent bounded disturbances

In this paper, a novel technique for Takagi–Sugeno (TS) model-based robust L₁ controller design of nonlinear systems is proposed. Two synthesis methods based on quadratic and non-quadratic Lyapunov functions are considered. To design the robust stabilizing controller, a new approach for deriving sufficient conditions associated with the L₁ performance criterion in terms of strict linear matrix inequality is proposed. This novel technique results in less pre-chosen scalar design variables and calculation burden. Furthermore, deriving the controller synthesis conditions via a non-quadratic Lyapunov function (NQLF) relaxes the obtained conditions. Therefore, the proposed approaches not only efficiently minimize the effect of persistent bounded disturbance, but also are applicable for wider classes of TS systems. Furthermore, some new lemmas are proposed to facilitate strict LMI formulation and to provide more degrees of freedom. Finally, several numerical and practical examples are presented to show the merits of this paper.     

Observer design for a class of nonlinear fractional-order systems with unknown input

A full order fractional-order observer is designed for a class of Lipschitz continuous-time nonlinear fractional-order systems with unknown input. Sufficient conditions of existence for the designed observer and stability of state estimation error system are developed by reconstructing state and using general quadratic Lyapunov function. By applying fractional-order extension of Lyapunov direct method, the stability of the fractional-order state estimation error system is analyzed. Due to the conditions involving a nonlinear matrix inequality, a new sufficient condition with linear matrix inequality (LMI) is reformulated, which makes the full order fractional-order observer implemented easily by using Matlab LMI toolbox. Examples are taken to show the effectiveness of the proposed approach by numerical simulations.