Observer Based Reliable Finite-time Consensus Under Actuator Faults for Uncertain Nonlinear Multi-agent Systems

Karthi Ramachandran,Jyh-Ching Juang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.9

The consensus problem for nonlinear multi-agent systems communicating on a connected undirected topology is addressed in this paper. The system nonlinearity of each agent accepts the one-sided Lipschitz and the quadratic-inner bounded properties. Furthermore, actuators of the agents are subject to a loss in their efficiency and are also assumed to have nonlinearity at the input. In addition, the agents are influenced by parametric uncertainties both at the system and input level, also bounded external disturbances affect the system states. To attain a consensus under these constraints, an observer-based state feedback protocol is developed. Subsequently, a robust finite-time boundedness study is performed by constructing an appropriate Lyapunov function from a closed loop observererror dynamics. Following this, the controller and observer gains are designed from the resulting linear matrix inequalities. This guarantees a reliable consensus among the agents in a finite time against actuator faults and uncertainties. The protocol’s effectiveness is shown by a suitable example.

Exploration of cell cycle regulation and modulation of the DNA methylation mechanism of pelargonidin: Insights from the molecular modeling approach

Karthi, N.,Karthiga, A.,Kalaiyarasu, T.,Stalin, A.,Manju, V.,Singh, S.K.,Cyril, R.,Lee, S.M. Pergamon 2017 Computational biology and chemistry Vol.70 No.-

<P>Pelargonidin is an anthocyanidin isolated from plant resources. It shows strong cytotoxicity toward various cancer cell lines, even though the carcinogenesis-modulating pathway of pelargonidin is not yet known. One of our previous reports showed that pelargonidin arrests the cell cycle and induces apoptosis in HT29 cells. Flowcytometry and immunoblot analysis confirmed that pelargonidin specifically inhibits the activation of CDK1 and blocks the G2-M transition of the cell cycle. In addition, DNA fragmentation was observed along with induction of cytochrome c release-mediated apoptosis. Hence, the aim of the present study was to investigate the molecular mechanism of pelargonidin's action on cell cycle regulators CDK1, CDK4, and CDK6 as well as the substrate-binding domain of DNMT1 and DNMT3A, which regulate the epigenetic signals related to DNA methylation. The results of docking analysis, binding free energy calculation, and molecular dynamics simulation correlated with the experimental results, and pelargonidin showed a specific interaction with CDK1. In this context, pelargonidin may also inhibit the recognition of DNA and catalytic binding by DNMT1 and DNMT3A. The HOMO-LUMO analysis mapped the functional groups of pelargonidin. Prediction of pharmacological descriptors suggested that pelargonidin can serve as a multitarget inhibitor for cancer treatment. (C) 2017 Elsevier Ltd. All rights reserved.</P>

(Zn, Ni)-ferrite nanoparticles for promoted osteogenic differentiation of MC3T3-E1 cells

Harshavardhan Mohan,Natesan Karthi,Pavithra Muthukumar Sathya,Vaikundamoorthy Ramalingam,Srivalli Thimmarayan,호싸인암자드,Adithan Aravinthan,신태호 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

The structural composition and functionality of bone tissues has been significantly impacted due to progressiveageing, thereby necessitating effective strategies that are not just about temporary cure butabout permanent regeneration of tissues, one such being regenerative medicine. Of the several noveltiesin the field, the provocation of osteogenesis involving nanoparticles has gained significant attention fortheir heightened efficiency and cost effectiveness. Magnetic materials in particular have been increasinglypaid attention to owing to their edge over stability, non-toxicity and feasibility to spatially trackusing MRI. The present study involves the synthesis of Zn and Ni doped ferrite ((Zn, Ni)-ferrite) nanoparticlesinvolving chemical co-precipitation method. The materials were evaluated against MC3T3 cellstowards ROS induced osteogenic differentiation properties, and the results implied very less toxicity evenat concentration surpassing 50 lg/ml in addition to the void of necrosis after treatment with 2.5 and5 lg/ml of (Zn, Ni)-ferrite. FACS results implied 1% cell staining with propidium iodide after 24 h exposureat 2.5 lg/ml concentrations of (Zn, Ni)-ferrite, thereby substantiating (Zn, Ni)-ferrite as a potentialbiomaterial in favor of regenerative medicine.

Effect of hybrid ceramic addition on Al7075 for prompt utilization

P. Sathiamurthi,K.S. Karthi Vinith,A. Sivakumar,N. Bagath Singh 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3

In recent engineering applications, lightweight aluminium composites are becoming more popular as an alternative for ferrousmetals. The high cost of component manufacture has kept particulate metal matrix composites from being widely used inengineering applications. The goal of this research is to characterize stir cast Al-7075/B4C/Si3N4 reinforced hybrid composites. Hard ceramic reinforcements increase the microstructure, mechanical, and wear qualities of the material. B4C and ZrB2particles were incorporated into the Al matrix at different weight percents, such as 2, 4, 6, and 8. The microstructure, andproperties of mechanical as well as wear of ZrB2 and B4C particle composition were examined. In addition, SEM and XRDwere used to investigate the castings' morphology. As a result, hardness and strength rise as the amount of B4C-ZrB2 in thecomposite increases. The Al7075 + 8% B4C + 1% ZrB2 composite outperform all the considered composition. Furthermore,with increasing sliding distances, the specific wear rate increases and the coefficient of friction decreases. Because of itsoutstanding mechanical and wear properties, the hybrid Al7075-B4C-ZrB2 material is the excellent choice of upper wingrequirements.

A pioneer scheme in the detection and defense of DrDoS attack involving spoofed flooding packets

( Kavisankar L ),( Chellappan C ),( Sivasankar P ),( Ashwin Karthi ),( Srinivas A ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.5

DDoS (Distributed Denial of Service) has been a continuous threat to the cyber world with the growth in cyber technology. This technical evolution has given rise to a number of ultra-sophisticated ways for the attackers to perform their DDoS attack. In general, the attackers who generate the denial of service, use the vulnerabilities of the TCP. Some of the vulnerabilities like SYN (synchronization) flooding, and IP spoofing are used by the attacker to create these Distributed Reflected Denial of Service (DrDoS) attacks. An attacker, with the assistance of IP spoofing creates a number of attack packets, which reflects the flooded packets to an attacker`s intended victim system, known as the primary target. The proposed scheme, Efficient Spoofed Flooding Defense (ESFD) provides two level checks which, consist of probing and non-repudiation, before allocating a service to the clients. The probing is used to determine the availability of the requested client. Non-repudiation is taken care of by the timestamp enabled in the packet, which is our major contribution. The real time experimental results showed the efficiency of our proposed ESFD scheme, by increasing the performance of the CPU up to 40%, the memory up to 52% and the network bandwidth up to 67%. This proves the fact that the proposed ESFD scheme is fast and efficient, negating the impact on the network, victim and primary target.

Novel and environmental friendly approach; Impact of Neem (<i>Azadirachta indica</i>) gum nano formulation (NGNF) on <i>Helicoverpa armigera</i> (Hub.) and <i>Spodoptera litura</i> (Fab.)

Kamaraj, Chinnaperumal,Gandhi, Pachiyappan Rajiv,Elango, Gandhi,Karthi, Sengodan,Chung, Ill-Min,Rajakumar, Govindasamy Elsevier 2018 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.107 No.1

<P><B>Abstract</B></P> <P>The future of this study was to prepare a natural pesticide which will not harm the environment and yet control pests. Neem gum nano formulation (NGNF), a novel biopesticide prepared from the Neem gum extract (<I>Azadirachta indica</I>) (NGE) was evaluated for its antifeedant, larvicidal and pupicidal activities against <I>Helicoverpa armigera</I> (Hub.) and <I>Spodoptera litura</I> (Fab.) at 100ppm. The NGNF showed significant (100%) antifeedant, larvicidal and pupicidal activities against <I>H. armigera</I> and <I>S. litura</I>. The LC<SUB>50</SUB> values of 10.20, 12.49 and LC<SUB>90</SUB> values of 32.68, 36.68ppm on <I>H. armigera</I> and <I>S. litura</I>, respectively at 100ppm. The NGNF treatments showed differences in the activities of detoxifying enzymes, carboxylesterases, glucosidases and glutathione S-transferases in the larval gut. Earthworm toxicity illustrated that 6.25ppm of chemical insecticides (cypermethrin) varied widely in their contact toxicities compared to 100ppm of NGNF and control in both contact filter paper and artificial soil test. The NGNF were characterized and confirmed by FTIR, XRD, SEM and EDX analysis. Ten compounds were identified from the Neem gum extract (NGE) by Gas Chromatography-Mass Spectrometry (GC–MS) analysis. The major compounds were fatty acids like Hexadecanoic acid, oleic acid, and ricinoleic acid. NGNF could be used as an agent to prepare novel bio-pesticides formulations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Neem gum mediated nano formulation (NGNF) as a bio-pesticide agent against <I>Helicoverpa armigera</I> and <I>Spodoptera litura</I>. </LI> <LI> NGNF exhibited potential antifeedant, larvicidal and pupicidal activities against <I>Helicoverpa armigera</I> and <I>Spodoptera litura</I>. </LI> <LI> Environmental toxicity was assessed by earthworm (<I>Eudrilus eugeniae</I>) there is no significant toxicity observed in NGNF treatments. </LI> </UL> </P>

A Dynamic QoS Model for improving the throughput of Wideband Spectrum Sharing in Cognitive Radio Networks

( K. Manivannan ),( C. G. Ravichandran ),( B. Sakthi Karthi Durai ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

A novel herbal product based on Piper betle and Sphaeranthus indicus essential oils: Toxicity, repellent activity and impact on detoxifying enzymes GST and CYP450 of Aedes aegypti Liston (Diptera: Culicidae)

Prabhakaran Vasantha-Srinivasan,Muthiah Chellappandian,Muthiah Chellappandian,Sengottayan Senthil-Nathan,Athirstam Ponsankar,Annamalai Thanigaivel,Sengodan Karthi,Edward-Sam Edwin,Selvaraj Selin-Rani 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4

Fresh leaves of Piper betle Linn. (Piperales: Piperaceae) and Sphaeranthus indicus Linn. (Asterales: Asteraceae), commonly known as betel leaves and East Indian globe thistle, respectively, were harvested and steam distilled for the extraction of P. betle and S. indicus crude volatile oils (Pb-CVO and Si-CVO, respectively). LC 50 calculated on 3 rd instar larvae of dengue mosquito Aedes aegypti Linn. (Diptera: Culicidae) was 42.17 ppm for PbSi-CVO (i.e., herbal formulation based on the EOs of P. betle and S. indicus). The larval and pupal duration were significantly longer post-treatment with 100 ppm of PbSi-CVO, if compared to control. We observed that PbSi-CVO significantly altered the detoxifying enzymes GST and CYP450 compared to the expression of control. Sub-lethal concentrations of PbSi-CVO showed strong repellent properties against dengue mosquitoes, without adverse reactions on the volunteers experiencing the repellent assays. Lastly, the adulticidal activity of PbSi-CVO was studied. Overall, our study outlined that this herbal product represents a promising candidate for the development of botanical based adulticidal agents.