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1.
ISA Trans ; 144: 18-27, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37914614

RESUMO

This work is devoted the problem of a security-guaranteed filter design for a class of discrete-time Markov jump systems that are vulnerable to stochastic deception attacks and have random sensor saturation. Deception attacks, in particular, are taken into account in the filter when the attacker attempts to modify the broadcast signal in communication networks by inserting some misleading information data into the assessment output. The Bernoulli distribution is satisfied by two sets of introduced stochastic variables. It shows the likelihood that the broadcaster's data transmissions will be the focus of deception attacks and sensor saturation. The Lyapunov functional technique is established, and criteria are derived to ensure that the system is mean-square stable. Furthermore, explicit expression of the filter gains is obtained by solving a set of linear matrix inequalities. Lastly, two simulation examples including a synthetic genetic regulatory network are provided to further demonstrate the validity and efficiency of the suggested theoretical results.

2.
Small ; 20(11): e2305758, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37936297

RESUMO

Recently, sulfide-based all-solid-state batteries (ASSBs) have attracted great attention because of their excellent safety and high energy density. However, by-products formed from side-reactions between the oxide-based cathodes and sulfide-based solid electrolytes (SEs) increase the interfacial resistance and degrade the cell performance. Suppression of this interfacial resistance is thus critical. In this study, the extraordinarily high stability of the cathode/SE interface is discovered when a Li10 SnP2 S12 (LSnPS) is applied to a cathode buffer layer. The electrochemical properties of the cathode interface at high potential are improved by synthesizing a core-shell structure cathode using LSnPS. The synthesized LSnPS is uniformly coated on a Li2 ZrO3 -coated LiNi0.8 Co0.1 Mn0.1 O2 (LZO-NCM) surface using the cost-efficient mechano-fusion method. The ASSB with LSnPS-coated LZO-NCM as the cathode and Li6 PS5 Cl (argyrodite, LPSCl) as the SE exhibited a capacity of 192 mAh g-1 and excellent cycle retention of ≈75% after 500 charge/discharge cycles. In addition, the degradation mechanism at the cathode/SE interface is investigated. The results indicated that LSnPS stabilizes the interface between NCM and argyrodite, thereby inhibiting the decomposition of the SE. This technology is expected to contribute to the commercialization of cathode materials for sulfide-based ASSBs due to its enhanced cycle performance, low-cost material application, and eco-friendly process.

3.
ISA Trans ; 143: 409-419, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37758524

RESUMO

In this paper, we focus on the real power sharing and frequency regulation of distributed generators in islanded microgrids with abnormal asynchronous stochastic cyber attacks, which is of great significance to the information security and stable operation of microgrids. Firstly, considering the possible cyber attacks in the communication network, a distributed non-fragile controller with coupled memory delay is proposed according to the nonperiodic sampled-data control. Then, the construction of delay-dependent two-sided looped-functional makes the Lyapunov-Krasovskii functional contain more delay and sampling information and relaxes constraints on free matrices. In addition, based on the enhanced integral inequality technique and the linear convex combination method, a sampling-based consensus protocol is presented to solve the issues of real power sharing and frequency regulation in the islanded microgrids. Finally, to verify the effectiveness and feasibility of the designed control strategy, a modified IEEE 34-bus test system is used for the experiment.

4.
IEEE Trans Cybern ; PP2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37738199

RESUMO

This article investigates the asymptotic stabilization of periodic piecewise time-varying systems with time-varying delay under various cyber attacks, particularly deception and DoS attacks. The addressed system is reformed into a number of time-varying subsystems based on the time interval for each period. Following that, a state-feedback controller with periodic time-varying gain parameters is developed to solve the stabilization problem. The control design depicts the possibility of the aforementioned cyber attacks with two mutually exclusive stochastic Bernoulli distributed parameters. Then, an augmented Lyapunov-Krasovskii functional with periodically varying matrices is used to determine the conditions for designing the proposed controller that ensures the mean-square asymptotic stability of the addressed system. The results of numerical examples support the conclusion that the proposed method is effective and superior, regardless of the cyber attacks involved.

5.
Neural Netw ; 165: 611-624, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37364471

RESUMO

This paper investigates an observer-based state estimation issue for discrete-time semi-Markovian jump neural networks with Round-Robin protocol and cyber attacks. In order to avoid the network congestion and save the communication resources, the Round-Robin protocol is used to schedule the data transmissions over the networks. Specifically, the cyber attacks are modeled as a set of random variables satisfying the Bernoulli distribution. On the basis of the Lyapunov functional and the discrete Wirtinger-based inequality technique, some sufficient conditions are established to guarantee the dissipativity performance and mean square exponential stability of the argument system. In order to compute the estimator gain parameters, a linear matrix inequality approach is utilized. Finally, two illustrative examples are provided to demonstrate the effectiveness of the proposed state estimation algorithm.


Assuntos
Algoritmos , Redes Neurais de Computação , Cadeias de Markov , Fatores de Tempo , Comunicação
6.
ACS Appl Mater Interfaces ; 14(38): 43372-43386, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36121788

RESUMO

Advancements in hypothetical metal-organic framework (hMOF) databases and construction tools have resulted in a rapidly expanding chemical design space for nanoporous materials. The bulk of these hypothetical structures are constructed using structural building units (SBUs) derived from experimental MOF structures, often collected from the CoRE-MOF database. Recent investigations into the state of these deposited experimental structures' chemical accuracy identified an array of common structural errors, including omitted protons, missing counterions, and disordered structures. These structural errors propagate into the SBUs mined from experimental MOFs, culminating in inaccurate hMOF structures possessing net charges or missing atoms which were not accounted for previously. This work demonstrates how manual investigation was applied to diagnose structural errors in SBUs obtained from several popular hMOF construction tools and databases. An analysis of the prevailing errors discovered during the examination process is provided along with representative cases to aid with error detection in future studies involving SBU extraction and hMOF construction. A novel repair protocol was established and employed to generate a library of SBUs that are hand-examined and labeled with enhanced detail (HEALED). This repaired library of SBUs contains 952 inorganic SBUs and 568 organic SBUs ideally suited for the generation of hypothetical frameworks that are chemically accurate and properly charge labeled. Additionally, case studies following the effects of SBU errors on electrostatic potential-fitted charges and GCMC-simulated gas adsorption predictions are presented to highlight the significance of using chemically accurate hMOF structures exclusively in all screening efforts going forward.

7.
Artigo em Inglês | MEDLINE | ID: mdl-35771779

RESUMO

This article is concerned with the fixed-time stability (FTS) problem of nonlinear impulsive systems (NISs). By means of the impulsive control mechanism and Lyapunov functions theory, several sufficient conditions are established to ensure the FTS of general NISs. Meanwhile, some novel impulse-dependent settling-time estimation schemes are developed, which fully considers the influence of stabilizing impulses and destabilizing impulses on the convergence rate of the system states. The proposed schemes establish a quantitative relationship between the upper bound of the settling time and impulse effects. It shows that stabilizing impulses can accelerate the convergence rate of the system states and leads to the upper bound of the settling time being smaller. Conversely, destabilizing impulses can reduce it and make the upper bound of the settling time larger. Then, the theoretical results are applied to delayed inertial neural networks (DINNs), where two kinds of controllers are designed to realize fixed-time synchronization of the considered systems in the impulse sense. Finally, some numerical examples are provided to illustrate the validity of the proposed theoretical results.

8.
BMC Health Serv Res ; 22(1): 102, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35078459

RESUMO

BACKGROUND: Many countries are trying to integrate traditional and complementary medicine (T&CM) into their health care systems. However, it is not easy to integrate T&CM within a given health care system. This study aims to draw policy outcomes and lessons from the case of Malaysia, which has been making efforts for over 20 years to integrate various types of T&CM into the national health care system (NHS). METHODS: Documents were searched in major databases and websites using words such as Malaysia and T&CM, and additional documents were secured using snowballing techniques. Data were classified and organized according to the World Health Organization health systems framework. RESULTS: Malaysia has focused on managing the safety and quality of T&CM, and to that end it has been institutionalized by enacting specialized laws rather than by applying existing medical law directly. Malaysia was able to institutionalize T&CM by adopting a step-by-step approach that considered the appropriateness of administrative policies and measures. CONCLUSIONS: Malaysia's experiences in implementing its T&CM policies will raise practical implications for countries struggling to integrate their existing T&CM into the NHS and utilize it for universal health coverage.


Assuntos
Medicina Tradicional , Cobertura Universal do Seguro de Saúde , Atenção à Saúde , Humanos , Malásia , Políticas
9.
Neural Netw ; 143: 209-217, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34157645

RESUMO

Most deep neural networks (DNNs) are trained with large amounts of noisy labels when they are applied. As DNNs have the high capacity to fit any noisy labels, it is known to be difficult to train DNNs robustly with noisy labels. These noisy labels cause the performance degradation of DNNs due to the memorization effect by over-fitting. Earlier state-of-the-art methods used small loss tricks to efficiently resolve the robust training problem with noisy labels. In this paper, relationship between the uncertainties and the clean labels is analyzed. We present novel training method to use not only small loss trick but also labels that are likely to be clean labels selected from uncertainty called "Uncertain Aware Co-Training (UACT)". Our robust learning techniques (UACT) avoid over-fitting the DNNs by extremely noisy labels. By making better use of the uncertainty acquired from the network itself, we achieve good generalization performance. We compare the proposed method to the current state-of-the-art algorithms for noisy versions of MNIST, CIFAR-10, CIFAR-100, T-ImageNet and News to demonstrate its excellence.


Assuntos
Algoritmos , Redes Neurais de Computação , Incerteza
10.
J Nanosci Nanotechnol ; 21(3): 1909-1914, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33404467

RESUMO

For this paper, we manufactured the 0.6/1 kV 3-core cable using metal-coated carbon fiber (MCF), which can be utilized for a cable screen layer. This cable can be applied to non-earthed system, and has a shielding property of more than 90% of braiding density. However, new joints and methods are needed to connect the cables because carbon fiber has brittleness. Thus, the cable connection added a spring to the contact surface, reducing resistance and fiber brittleness. These cables and connection methods were evaluated for safety in a certain temperature, humidity and over-current environments. From the results, the change of the external shape and contact resistance of the cable and the joint against the humidity and temperature were not significant, and the insulation breakdown did not occur in the withstanding voltage property of 3.5 kV for 5 min. No thermal deformation of the cable and connections was observed at the current above the allowable current range; it can be used as stable as metal screen cable.

11.
Sci Rep ; 10(1): 9672, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32541851

RESUMO

The formation of hydrogen blisters in the fabrication of tunnelling oxide passivating contact (TOPCon) solar cells critically degrades passivation. In this study, we investigated the formation mechanism of blisters during the fabrication of TOPCons for crystalline silicon solar cells and the suppression of such blisters. We tested the effects of annealing temperature and duration, surface roughness, and deposition temperature on the blister formation, which was suppressed in two ways. First, TOPCon fabrication on a rough surface enhanced adhesion force, resulting in reduced blister formation after thermal annealing. Second, deposition or annealing at higher temperatures resulted in the reduction of hydrogen in the film. A sample fabricated through low-pressure chemical vapor deposition at 580 °C was free from silicon-hydrogen bonds and blisters after the TOPCon structure was annealed. Remarkably, samples after plasma-enhanced chemical vapor deposition at 300, 370, and 450 °C were already blistered in the as-deposited state, despite low hydrogen contents. Analysis of the hydrogen incorporation, microstructure, and deposition mechanism indicate that in plasma-enhanced chemical vapor deposition (PECVD) deposition, although the increase of substrate temperature reduces the hydrogen content, it risks the increase of porosity and molecular-hydrogen trapping, resulting in even more severe blistering.

12.
Nat Commun ; 10(1): 3620, 2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399593

RESUMO

Composite metal-organic frameworks (MOFs) tend to possess complex interfaces that prevent facile and rational design. Here we present a joint computational/experimental workflow that screens thousands of MOFs and identifies the optimal MOF pairs that can seamlessly connect to one another by taking advantage of the fact that the metal nodes of one MOF can form coordination bonds with the linkers of the second MOF. Six MOF pairs (HKUST-1@MOF-5, HKUST-1@IRMOF-18, UiO-67@HKUST-1, PCN-68@MOF-5, UiO-66@MIL-88B(Fe) and UiO-67@MIL-88C(Fe)) yielded from our theoretical predictions were successfully synthesized, leading to clean single crystalline MOF@MOF, demonstrating the power of our joint workflow. Our work can serve as a starting point to accelerate the discovery of novel MOF composites that can potentially be used for many different applications.

13.
Arthroplast Today ; 5(1): 78-82, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31020028

RESUMO

BACKGROUND: The objective of this study was to assess the educational quality of YouTube videos pertaining to total knee arthroplasty and knee osteoarthritis. METHODS: A systematic search for the terms "knee replacement" and "knee arthritis" was performed using YouTube's search function. Data from the 60 most relevant videos were collected for each search term. Quality assessment checklists with a scale of 0 to 10 points were developed to evaluate the video content. Videos were grouped into poor quality (grade 0-3), acceptable quality (grade 4-7), and excellent quality (grade 8-10), respectively. RESULTS: Overall, 106 videos were categorized. For videos regarding total knee arthroplasty (n = 50), 64% of videos were of poor educational quality (32/50), 28% were of acceptable quality (14/50), and 8% were of good educational quality (4/50). Common missing information included discussion of surgical complications and implant duration. For videos regarding knee arthritis (n = 56), 66% of videos were of poor educational quality (37/56), 32% were of acceptable quality (18/56), and 2% were of good educational quality. Common missing information were causes and risk factors for knee arthritis and long-term prognosis. CONCLUSIONS: The present study suggests that YouTube is a poor educational source for patients regarding knee arthroplasty and knee arthritis. Recognizing the limitations of YouTube as well as which topics are not commonly presented may better guide physicians to educate their patients.

14.
Phys Chem Chem Phys ; 20(25): 17000-17008, 2018 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-29900454

RESUMO

Controlling wrinkle nanostructures of two-dimensional materials is critical for optimizing the material properties and device performance. In this study, we demonstrated the in situ synthesis of large-area MoS2 wrinkles on graphene by chemical-vapor-deposition-assisted sulfurization, and investigated the influence of graphene thickness and grain structures on the feature dimensions of MoS2 wrinkle nanostructures. The height, width, and overall surface roughness of the MoS2 wrinkles diminish as the number of graphene layers increases, which was further verified by determining the binding energy of graphene layers by density functional theory calculations. Furthermore, the feature dimensions of MoS2 wrinkle nanostructures were also influenced by graphene domain boundaries because of the difference in graphene nucleation density. This may be attributed to the influence of the mechanical properties of graphene substrates on the overall feature dimensions of MoS2 wrinkles, which are directly correlated with the interfacial adhesion energy. We believe that our findings may contribute toward the controllable synthesis of MoS2 wrinkle nanostructures and other two-dimensional materials used for high-performance devices.

15.
ACS Nano ; 12(2): 986-993, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29368519

RESUMO

Achieving high sensitivity in solid-state gas sensors can allow the precise detection of chemical agents. In particular, detection of volatile organic compounds (VOCs) at the parts per billion (ppb) level is critical for the early diagnosis of diseases. To obtain high sensitivity, two requirements need to be simultaneously satisfied: (i) low electrical noise and (ii) strong signal, which existing sensor materials cannot meet. Here, we demonstrate that 2D metal carbide MXenes, which possess high metallic conductivity for low noise and a fully functionalized surface for a strong signal, greatly outperform the sensitivity of conventional semiconductor channel materials. Ti3C2Tx MXene gas sensors exhibited a very low limit of detection of 50-100 ppb for VOC gases at room temperature. Also, the extremely low noise led to a signal-to-noise ratio 2 orders of magnitude higher than that of other 2D materials, surpassing the best sensors known. Our results provide insight in utilizing highly functionalized metallic sensing channels for developing highly sensitive sensors.

16.
IET Syst Biol ; 12(4): 131-137, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33451185

RESUMO

This study aims at designing an observer-based resilient controller to regulate the amount of oxygen and carbon dioxide in the blood of patients during the extra-corporeal blood circulation process. More precisely, in this study, a suitable observer-based resilient controller is constructed to regulate the levels of patient blood gases in a finite interval of time. The finite-time boundedness with the prescribed H ∞ performance index of the considered blood gases control system against modelling uncertainty and external disturbances is ensured by using Lyapunov stability analysis. Moreover, a set of sufficient conditions for obtaining the controller gain is developed in the form of linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed robust finite-time control scheme is verified through simulation results. The result reveals that the blood gases are maintained in their physiological ranges during a stable extra-corporeal circulation process via the proposed observer-based resilient controller.

17.
IEEE Trans Cybern ; 48(7): 2192-2202, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28885163

RESUMO

This paper investigates synchronization in complex dynamical networks (CDNs) with interval time-varying delays. The CDNs are representative of systems composed of a large number of interconnected dynamical units, and for the purpose of the mathematical analysis, the leading work is to model them as graphs whose nodes represent the dynamical units. At this time, we take note of the importance of each node in networks. One way, in this paper, is that the closeness-centrality mentioned in the field of social science is grafted onto the CDNs. By constructing a suitable Lyapunov-Krasovskii functional, and utilizing some mathematical techniques, the sufficient and closeness-centrality-based conditions for synchronization stability of the networks are established in terms of linear matrix inequalities. Ultimately, the use of the closeness-centrality can be weighted with regard to not only the interconnection relation among the nodes, which was utilized in the existing works but also more information about nodes. Here, the centrality will be added as the concerned information. Moreover, to avoid the computational burden causing the nonconvex term including the square of the time-varying delay, how to deal with it is applied by estimating it to the convex term including time-varying delay. Finally, two illustrative examples are given to show the advantage of the closeness-centrality in point of the robustness on time-delay.

18.
Chem Mater ; 29(7): 2844-2854, 2017 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-28413259

RESUMO

The Materials Genome is in action: the molecular codes for millions of materials have been sequenced, predictive models have been developed, and now the challenge of hydrogen storage is targeted. Renewably generated hydrogen is an attractive transportation fuel with zero carbon emissions, but its storage remains a significant challenge. Nanoporous adsorbents have shown promising physical adsorption of hydrogen approaching targeted capacities, but the scope of studies has remained limited. Here the Nanoporous Materials Genome, containing over 850 000 materials, is analyzed with a variety of computational tools to explore the limits of hydrogen storage. Optimal features that maximize net capacity at room temperature include pore sizes of around 6 Šand void fractions of 0.1, while at cryogenic temperatures pore sizes of 10 Šand void fractions of 0.5 are optimal. Our top candidates are found to be commercially attractive as "cryo-adsorbents", with promising storage capacities at 77 K and 100 bar with 30% enhancement to 40 g/L, a promising alternative to liquefaction at 20 K and compression at 700 bar.

19.
Chem Commun (Camb) ; 53(12): 1953-1956, 2017 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-28000805

RESUMO

We present a computational algorithm that can screen through a database of metal-organic framework structures and identify materials that lead to hetero-interpenetration with targeted porous materials. Two MOFs (IRMOF-1 and IRMOF-8) were selected as target materials and our algorithm identified PCN-68 and PCN-610 as matching candidates for interpenetration. Molecular simulation results indicate that the interpenetrated MOFs possess enhanced methane and hydrogen adsorption properties compared to the parent materials.

20.
Bioprocess Biosyst Eng ; 39(7): 1173-80, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27003825

RESUMO

This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications.


Assuntos
Carboidratos/biossíntese , Gracilaria/metabolismo , Ácidos Fosfóricos/química , Biomassa , Catálise , Hidrólise , Temperatura
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