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Analysis and design of secure cyber-physical systems

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Control Theory and Technology 2014年第4期12卷 413-414页

作者： ling shi School of Engineering Hong Kong University of Science & Technology

Cyber-physical systems （CPSs） are new emerging systems that seamlessly integrate physical systems, communication systems and computation systems. Their wide use has been witnessed in the past decades in many crossdiscipline fields such as smart energy systems, industrial process control, aerospace and automobile engineering, health-care and assisted living, to just name a few. For many of these systems, secure operations are of key con- cerns. In particular, for some safety-critical applications, security is of paramount importance. Diverse motivations and strong incentives exist everywhere and at any time for launching malicious attacks on the CPSs, for example, economic reasons （e.g., by reducing or even not paying electricity charge） and terrorism the purpose of which is apparent.

关键词： Analysis and design of secure cyber-physical systems CPS

A Comparison of Corrosion Behavior in Saline Environment: Rare Earth Metals (Y, Nd, Gd, Dy) for Alloying of Biodegradable Magnesium Alloys

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Journal of Materials Science & Technology 2013年第9期29卷 781-787页

作者： Xu Zhao ling-ling shi Jian Xu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

Rare earth （RE） metals are widely used as the alloying implants. However, corrosion behavior of pure RE elements in biodegradable magnesium alloys as medical metals not only in physiological media but also in chlorinated saline environment is not well understood. In the present work, the RE metals Y, Nd, Gd and Dy are selected to investigate their corrosion behavior in 0.1 mol/L NaCI solution with immersion and electrochemistry techniques. As indicated, corrosion of the currently investigated RE metals is promoted in the order of Dy, Y, Gd and Nd. In terms of electrochemical response, such a sequence correlates with the increased impedance and the decreased corrosion rate （CR）. These RE metals manifest weak ability for passivation in the native surface. Then, reaction with aqueous solution easily happens through the anodic dissolution and cathodic hydrogen evolution. The corrosion products, RE（OH）3, adhered on the surface of RE metals, do not have an appreciable power to resist the reaction proceeding with corrosive chloride ions. In contrast to pure Mg, the RE metals, including Y, Nd, Gd and Dy, exhibit significantly fragile corrosion resistance in saline media. Therefore, with the curr correlation of corrosion resistance between RE-contain ent findings, it is impossible to reveal a well-defined ng Mg alloy and RE metal itself

关键词： Rare earth Biodegradable metal Magnesium alloy Corrosion behavior

Unicyclic Graphs of Minimal Spectral Radius

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Acta Mathematica Sinica,English Series 2013年第2期29卷 281-286页

作者： ling Sheng shi Department of Mathematical Sciences Tsinghua University

It was conjectured by Li and Feng in 1979 that the unicyclic graph formed by a cycle of order g linking to an endvertex of a path of length k minimizes the spectral radius of all unicyclic graphs of order g ＋ k and girth g. In 1987, Cao proved that this conjecture is true for k ≥ g（g - 2）/8 and false for k = 2 and sufficiently large g. In this note, we show that g 〉12 suffices for the counterexample and give more counterexamples with large girth for any integer k 〉 1.

关键词： Extremal graph Li-Feng's conjecture spectral radius unicyclic

Zero-forcing beamforming with receiver antenna selection in downlink multi-antenna multi-user system

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1258-1263页

作者： Huang Senhua Qiu ling shi Lin PCN & SS Lab Univ. of Science and Technology of China Hefei 230027 P. R. China

A study on the zero-forcing beamforming （ZFBF） scheme with antenna selection at user terminals in downlink multi-antenna multi-user systems is presented. Simulation results show that the proposed ZFBF scheme with receiver antenna selection （ZFBF-AS） achieves considerable throughput improvement over the ZFBF scheme with single receiver antenna. The results also show that, with multi-user diversity, the ZFBF-AS scheme approaches the throughput performance of the ZFBF scheme using all receiver antennas （ZFBF-WO-AS） when the base station adopts semi-orthogonal user selection （SUS） algorithm, and achieves larger throughput when the base station adopts the Round-robin scheduling algorithm. Compared with ZFBF-WO-AS, the proposed ZFBF-AS scheme can reduce the cost of user equipments and the channel state information requirement at the transmitter （CSIT） as well as the multiuser scheduling complexity at the transmitter.

关键词： downlink multi-antenna multi-user system zero-forcing beamforming antenna selection throughput performance

Conditional Connectivity of Bubble Sort Graphs

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Acta Mathematicae Applicatae Sinica 2017年第4期33卷 933-944页

作者： ling-sheng shi Peng WU Department of Mathematical Sciences Tsinghua University Beijing 100084 China

A subset F V（G） is called an Rk-vertex-cut of a graph G if G - F is disconnected and each vertex of G - F has at least k neighbors in G - F. The Rk-vertex-connectivity of G, denoted by κk（G）, is the cardinality of a minimum Rk-vertex-cut of G. Let Bn be the bubble sort graph of dimension n. It is known that κk（Bn） = 2k（n - k - 1） for n _〉 2k and k = 1,2. In this paper, we prove it for k =3 and conjecture that it is true for all k ∈ N. We also prove that the connectivity cannot be more than conjectured.

关键词： bubble sort graph connectivity cut

Is adult celiac disease really uncommon in Chinese?

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第3期10卷 168-171页

作者： ling-ling JIANG Bing-ling ZHANG You-shi LIU Department of Gastroenterology the First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310003 China)

Celiac disease(CD) is a type of intestinal malabsorption syndrome,in which the patients are intolerant to the gliadin in dietary gluten,resulting in chronic diarrhea and secondary malnutrition. The disease is common in Europe and the United States,but only sporadic reports are found in East Asia including China. Is CD really rare in China? We examined 62 patients by capsule endoscopy for chronic diarrhea from June 2003 to March 2008. Four patients with chronic diarrhea and weight loss were diagnosed to have CD. Under the capsule endoscopy,we observed that the villi of the proximal small bowel became short,and that the mucous membrane became atrophied in these four patients. Duodenal biopsies were performed during gastroscopy and the pathological changes of mucosa were confirmed to be Marsh 3 stage of CD. A gluten free diet significantly improved the conditions of the four patients. We suspect that in China,especially in the northern area where wheat is the main food,CD might not be uncommon,and its under-diagnosis could be caused by its clinical manifestations that could be easily covered by the symptoms from other clinical situations,particularly when it came to subclinical patients without obvious symptom or to patients with ex-traintestinal symptoms as the initial manifestations.

关键词： Celiac disease (CD) China Gluten Prevalence Capsule endoscopy

Online Pareto optimal control of mean-field stochastic multi-player systems using policy iteration

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Science China(Information Sciences) 2024年第4期67卷 21-37页

作者： Xiushan JIANG Yanshuang WANG Dongya ZHAO ling shi College of New Energy China University of Petroleum(East China) Department of Electronic and Computer Engineering Hong Kong University of Science and Technology

In this study, the Pareto optimal strategy problem was investigated for multi-player mean-field stochastic systems governed by It? differential equations using the reinforcement learning(RL) method.A partially model-free solution for Pareto-optimal control was derived. First, by applying the convexity of cost functions, the Pareto optimal control problem was solved using a weighted-sum optimal control problem. Subsequently, using on-policy RL, we present a novel policy iteration(PI) algorithm based on the Hrepresentation technique. In particular, by alternating between the policy evaluation and policy update steps,the Pareto optimal control policy is obtained when no further improvement occurs in system performance,which eliminates directly solving complicated cross-coupled generalized algebraic Riccati equations(GAREs).Practical numerical examples are presented to demonstrate the effectiveness of the proposed algorithm.

关键词： mean-field stochastic systems Pareto optimal control policy iteration scheme $\mathcal{H}$-representation

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Novel milestones for early esophageal carcinoma:From bench to bed

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1104-1118页

作者： Ji-Han Qi shi-ling Huang shi-Zhu Jin Department of Gastroenterology and Hepatology The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150086Heilongjiang ProvinceChina

Esophageal cancer(EC)is the seventh most common cancer worldwide,and esophageal squamous cell carcinoma(ESCC)accounts for the majority of cases of *** effectively diagnose and treat ESCC and improve patient prognosis,timely diagnosis in the initial phase of the illness is *** article offers a detailed summary of the latest advancements and emerging technologies in the timely identification of *** biology and epigenetics approaches involve the use of molecular mechanisms combined with fluorescence quanti-tative polymerase chain reaction(qPCR),high-throughput sequencing technology(next-generation sequencing),and digital PCR technology to study endogenous or exogenous biomolecular changes in the human body and provide a decision-making basis for the diagnosis,treatment,and prognosis of *** invest-igation of the microbiome is a swiftly progressing area in human cancer research,and microorganisms with complex functions are potential components of the tumor *** intratumoral microbiota was also found to be connected to tumor *** application of endoscopy as a crucial technique for the early identification of ESCC has been essential,and with ongoing advancements in technology,endoscopy has continuously *** the advancement of artificial intelligence(AI)technology,the utilization of AI in the detection of gastrointestinal tumors has become increasingly *** implementation of AI can effectively resolve the discrepancies among observers,improve the detection rate,assist in predicting the depth of invasion and differentiation status,guide the pericancerous margins,and aid in a more accurate diagnosis of ESCC.

关键词： Early esophageal squamous cell carcinoma Epidemiology and risk factors Molecular biology Epigenetic Microbiology Endoscopy and artificial intelligence

L_p approximation by Bernstein-Kantorovich quasi-interpolants

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Applied Mathematics(A Journal of Chinese Universities) 2009年第2期24卷 200-208页

作者： LIU Li-xia shi ling GUO Shun-sheng College of Math. and Inform. Sci. Hebei Normal Univ. Shijiazhuang 050016 China

Bernstein-Kantorovich quasi-interpolants K^（2r-1）n（f, x） are considered and direct, inverse and equivalence theorems with Ditzian-Totik modulus of smoothness ω^2rφ（f, t）p （1 ≤ p ≤＋∞） are obtained.

关键词： quasi-interpolant Bernstein-Kantorovich operator Ditzian-Totik modulus