Sliding mode control for Markov jump linear uncertain systems with partly unknown transition rates

In this paper, based on sliding mode control approach, the robust stabilisation problem for a class of continuous-time Markovian jump linear uncertain systems with partly unknown transition rates is investigated. The transition rate matrix under consideration covers completely known, boundary known and completely unknown elements. By making use of linear matrix inequalities technique, sufficient conditions are presented to derive the linear switching surface and guarantee the stochastic stability of sliding mode dynamics. Then a sliding mode control law is designed to drive the state trajectory of the closed-loop system to the specified linear switching surface in finite time in spite of the existing uncertainties and unknown transition rates. Finally, an example is given to verify the validity of the theoretical results.     

Heterogeneous Fenton-like discoloration of methyl orange using Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/MWCNTs as catalyst: combination mechanism and affecting parameters

Multi-walled carbon nanotubes (MWCNTs) can act not only as a support for Fe₃O₄ nanoparticles (NPs) but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe₃O₄ NPs. In this study, Fe₃O₄ NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe₃O₄/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe₃O₄ crystals in Fe₃O₄/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe₃O₄ NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe₃O₄ NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe₃O₄/MWCNTs nanocomposites.     

Distributed interactive video system design and analysis

The interactive video (IV) market has been expected to capture a significant share of the huge potential revenues to be generated by the business and residential markets. The level of revenues generated depends on the completion rate of calls the service provider can support, no matter what the IV system or network condition. Thus, a cost-effective, scalable fault-tolerant IV system is needed to maximize the video call completion rate at an affordable cost. This article describes design methodologies for a scalable, fault-tolerant IV system and an IV system design and analysis research prototype called IVSDNA (IV System Designer and Analyzer). The IVSDNA prototype is designed to help network planners and engineers to evaluate quantitative trade-offs (in terms of network communications costs, video storage costs, and degree of system fault tolerance) between two major IV system architectures (centralized and distributed) with a variety of video distribution methods, replication strategies, and fault-tolerant access protocols     

黑龙江省瓶(桶)装饮用水中阴离子检测结果分析

目的了解和分析黑龙江省瓶(桶)装饮用水中阴离子检测结果。方法按照《食品安全国家监督抽检和风险监测计划》要求,对全省流通和生产加工环节的瓶(桶)装饮用水的水中阴离子进行检测分析。结果共抽检486批次样品,总合格率为96.5%。按照不合格率由高到低,依次为瓶装饮用水5.6%,纯净水1.96%,矿泉水1.67%;不合格项目为亚硝酸盐、溴酸盐和硝酸盐,不合格率分别为0.62%、3.9%、0.83%。结论黑龙江省生产和流通环节饮用水水中阴离子情况整体较好,但仍需加大监管监测力度,尤其是对瓶装饮用水需要进行重点监测,对于溴酸盐和硝酸盐2种离子也要进行重点监测。     

A sliding sector approach to quantized feedback variable structure control

This paper is concerned with the quantized feedback quadratic stabilization problem for linear time-invariant systems. Sliding sector based quantized state feedback variable structure control schemes are established. The main benefit of the sliding sector technique is that it can avoid chattering caused by the utilization of variable structure control strategy. With the proposed discrete on-line adjustment of the quantization parameter, it is shown that the proposed sliding sector based sliding mode controllers can tackle state quantization and guarantee quadratic stability of the closed-loop system. Simulation results are given to verify the effectiveness of the proposed method.     

Heterogeneous Fenton-like discoloration of methyl orange using Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/MWCNTs as catalyst: kinetics and Fenton-like mechanism

The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe₃O₄/MWCNTs-H₂O₂ Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first-order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ·mol^-1 and 2.72 s^-1, respectively. The quantifications of Fe ions dissolution and ?OH radicals generation confirmed that the homogeneous and heterogeneous catalyses were involved in Fe₃O₄/MWCNTs-H₂O₂ Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and ?OH radicals generation. Fe₃O₄/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe₃O₄/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.     

A Context Adaptive Intrusion Detection System for MANET

Due to the ad hoc and mobile nature of a MANET, it is much more vulnerable to attacks than a wired network. As a result, there has been a significant research focusing on designing an Intrusion Detection System (IDS) for MANETs to detect anomalous behavior and misuse. However, each mobile node in a MANET typically has limited energy and thus it is not efficient to perform IDS functions within a node to detect every incoming packet. There is a need for an IDS to implement an intelligent control mechanism in order to monitor and recognize security breach attempts efficiently over a period of the expected network lifetime. By leveraging the Network Node Intrusion Detection (NNID) strategy, we developed a context adaptive IDS controller that advises an IDS to carry out intrusion detection while being prepared for a possible “cut through” if it is likely that the residual energy is not sufficient. By being embedded with the context adaptive IDS controller, the proposed Context Adaptive Intrusion Detection System (CAIDS) is able to adapt to the current node context (such as residual energy, security threats and traffic loading) for accommodating and inspecting new arriving packets. The performance is evaluated using a reward function that discovers an effective way to perform intrusion detection and delivers security benefits while meeting the energy budget. The numerical results show that CAIDS offers a good trade-off between lifetime performance and security. This study demonstrates empirically that the CAIDS model intelligently monitors and recognizes security breach attempts while adhering to the resource budget plan over the period of expected network lifetime.     

Special point representations for reducing data space requirements of finger-vein recognition applications

Due to the uniqueness of the finger-vein patterns hidden beneath the skin, forgery is very difficult. Providing fast and accurate finger-vein recognition represents the answer to biometric security system as we need more secure and reliable authentication methods. However, the finger-vein based recognition system is limited by the storage space and time complexity, which significantly reduce the accuracy of the identification. In this paper, we present an effective method of matching in a finger-vein recognition system to overcome the disadvantage of requiring significant data storage and heavy CPU computation requirements. Our proposed solution involved considering special points characterizing complex finger-vein information and their connections, thereby retaining only the evidence related to matching to perform subsequent identification. Experimental results show that our method achieves robust matching with an error rate of 0.216 % and confirm that the proposed mechanism can reduce the quantity of data that requires storage and maintain a certain level of authentication accuracy.     

Network lifetime bounds for hierarchical wireless sensor networks in the presence of energy constraints

In previous years, one popular problem that is constantly being researched into is how to prolong the lifetime of wireless sensor networks (WSNs). Many approaches to maximize network lifetime have been proposed and each approach provides different levels of energy savings and are efficient in their own aspects. However, these proposed algorithms are not suitable for use in a hard network lifetime environment where participating sensors should be working till the strict network lifetime requirement. The predictability of the network lifetime plays an important role in supporting guaranteed network lifetime services. This can be provided through the schedulability test that complements the online operations of safe and critical sensor network systems. In this paper, we focus on the study of the predictability of the network lifetime to enable the High Energy First clustering algorithm (HEF) to work in a hard lifetime environment and present a schedulability test to verify whether HEF can make the set of sensors schedulable in terms of N-of-N and K-of-N alive nodes.