Centralized Versus Decentralized Detection of Attacks in Stochastic Interconnected Systems

We consider a security problem for interconnected systems governed by linear, discrete, time-invariant, stochastic dynamics, where the objective is to detect exogenous attacks by processing the measurements at different locations. We consider two classes of detectors, namely centralized and decentralized detectors, which differ primarily in their knowledge of the system model. In particular, a decentralized detector has a model of the dynamics of the isolated subsystems, but is unaware of the interconnection signals that are exchanged among subsystems. Instead, a centralized detector has a model of the entire dynamical system. We characterize the performance of the two detectors and show that, depending on the system and attack parameters, each of the detectors can outperform the other. In particular, it may be possible for the decentralized detector to outperform its centralized counterpart, despite having less information about the system dynamics, and this surprising property is due to the nature of the considered attack detection problem. To complement our results on the detection of attacks, we propose and solve an optimization problem to design attacks that maximally degrade the system performance while maintaining a pre-specified degree of detectability. Finally, we validate our findings via numerical studies on an electric power system.Comment: Submitted to IEEE Transactions on Automatic Control (TAC

On a Security vs Privacy Trade-off in Interconnected Dynamical Systems

We study a security problem for interconnected systems, where each subsystem aims to detect local attacks using local measurements and information exchanged with neighboring subsystems. The subsystems also wish to maintain the privacy of their states and, therefore, use privacy mechanisms that share limited or noisy information with other subsystems. We quantify the privacy level based on the estimation error of a subsystem's state and propose a novel framework to compare different mechanisms based on their privacy guarantees. We develop a local attack detection scheme without assuming the knowledge of the global dynamics, which uses local and shared information to detect attacks with provable guarantees. Additionally, we quantify a trade-off between security and privacy of the local subsystems. Interestingly, we show that, for some instances of the attack, the subsystems can achieve a better detection performance by being more private. We provide an explanation for this counter-intuitive behavior and illustrate our results through numerical examples.Comment: Under review in the journal Automatic

Explicit Uncertainty word directing through Data Mining

Searching a keyword on an enormous a colossal is somewhat easier, however the search over a enlarge range of structured and connected information creates a problem. Routing keywords solely to applicable sources will scale back the high value of looking of queries over all sources. It’s tough for net user to use this net information by means that of SQL or SPARQL. we tend to rent a keyword component relationship outline that succinctly represents relationships between keywords and also the information parts referred to as the set-level keyword-element relationship graph (KERG).A structure rating mechanism is recommended for computing the relevant of routing plans supported the extent of keyword, information parts , component sets and sub graphs that connect these parts. The web may be a not operation it's solely provides a link for looking the online document supported the keyword. The question may be shaped from keywords that square measure wont to retrieve the document. It’s tough for the standard net users to take advantage of this net information by means that of structured queries exploitation languages like SQL or SPARQL. In info analysis, most of the approaches use solely the only supply solutions. The most issue here is computing the foremost relevant mixtures of sources. To route keywords solely to relevant sources, a completely unique methodology is projected for computing top-k routing plans supported their keyword question. The keyword-element relationship outline is employed to represents the relationships between keywords and also the information parts. Structure rating mechanism is projected for computing the connection of routing plans supported scores at the extent of keywords and information parts. It’s no data regarding the command language and it as hostile structured queries. That the schema or the underlying information is required

Better under stress: Improving bacterial cellulose production by Komagataeibacter xylinus K2G30 (UMCC 2756) using adaptive laboratory evolution

Among naturally produced polymers, bacterial cellulose is receiving enormous attention due to remarkable properties, making it suitable for a wide range of industrial applications. However, the low yield, the instability of microbial strains and the limited knowledge of the mechanisms regulating the metabolism of producer strains, limit the large-scale production of bacterial cellulose. In this study, Komagataeibacter xylinus K2G30 was adapted in mannitol based medium, a carbon source that is also available in agri-food wastes. K. xylinus K2G30 was continuously cultured by replacing glucose with mannitol (2% w/v) for 210 days. After a starting lag-phase, in which no changes were observed in the utilization of mannitol and in bacterial cellulose production (cycles 1-25), a constant improvement of the phenotypic performances was observed from cycle 26 to cycle 30, accompanied by an increase in mannitol consumption. At cycle 30, the end-point of the experiment, bacterial cellulose yield increased by 38% in comparision compared to cycle 1. Furthermore, considering the mannitol metabolic pathway, D-fructose is an intermediate in the bioconversion of mannitol to glucose. Based on this consideration, K. xylinus K2G30 was tested in fructose-based medium, obtaining the same trend of bacterial cellulose production observed in mannitol medium. The adaptive laboratory evolution approach used in this study was suitable for the phenotypic improvement of K. xylinus K2G30 in bacterial cellulose production. Metabolic versatility of the strain was confirmed by the increase in bacterial cellulose production from D-fructose-based medium. Moreover, the adaptation on mannitol did not occur at the expense of glucose, confirming the versatility of K2G30 in producing bacterial cellulose from different carbon sources. Results of this study contribute to the knowledge for designing new strategies, as an alternative to the genetic engineering approach, for bacterial cellulose production

A Novel Controlled Method Of Transformer Less Cascaded H-Bridge STATCOM

This work is a mix of transformer less static synchronous compensator (STATCOM) and Cascade multilevel H-connect converter topology. This proposed controller current circle as well as have dc capacitor voltage control. As to the present circle control, a nonlinear controller in light of the resignation based control (PBC) hypothesis is utilized as a part of this Cascade structure STATCOM surprisingly. With regards to the dc capacitor voltage control, general voltage control is acknowledged by embracing a corresponding full controller. Bunched adjusting control is acquired by utilizing a dynamic unsettling influences dismissal controller. The recreation comes about demonstrate that H-connect Cascade STATCOM with the proposed control techniques has amazing dynamic execution and solid power. The dc capacitor voltage can be kept up at the given esteem adequately. Fuzzy controller is utilized to decrease the swells and better smoothening of the wave shapes. The outcomes dissected through MATLAB/SIMULINK condition

Gemini imidazolium gels enhance the photodynamic performance of porphyrins

Photodynamic therapy (PDT) successful clinical use has led to an emerging interest in the development of improved delivery systems for photosensitizers. Amongst different formulations, gels have the advantage of being easier to apply, providing greater adhesion to the affected region and allowing light penetration. Importantly, we have previously reported that by incorporating porphyrin into a bisimidazolium gelator matrix there is an increased reactive oxygen species (ROS) generation compared to the photosensitizer in solution [1]. Motivated by this, we report further assessment on the photosensitizing capabilities of porphyrins in a gel structure. In this work, we evaluated effect of varying the chemical structures of porphyrins on their photosensitizing capabilities whilst embedded within a supramolecular hydrogel based on gemini imidazolium amphiphiles. The investigated porphyrins presented enhanced singlet oxygen (1O2) within the hydrogel matrix compared to solution and showed negligent release in relevant biological media. Rheological measurements revealed that porphyrin hydrogels presented desirable viscoelastic properties as a functional delivery system for PDT

Assessing effectiveness of Komagataeibacter strains for producing surface-microstructured cellulose via guided assembly-based biolithography.

In this study, a medical device made of surface microstructured bacterial cellulose was produced using cellulose‑producing acetic acid bacteria wild‑type strains in combination with guided assembly‑based biolithography. The medical device aims at interfering with the cell’s focal adhesion establishment and maturation around implantable devices placed in soft tissues by the symmetrical array on its surface. A total of 25 Komagataeibacter strains was evaluated over a three‑step selection. In the first step, the ability of strains to produce a suitable bacterial cellulose layer with high production yield was examined, then nine strains, with a uniform and smooth layer of bacterial cellulose, were cultured in a custom‑made silicone bioreactor and finally the characteristics of the symmetrical array of topographic features on the surface were analysed. Selected strains showed high inter and intra species variability in bacterial cellulose production. The devices obtained by K2G30, K1G4, DSM 46590 (Komagataeibacter xylinus), K2A8 (Komagataeibacter sp.) and DSM 15973T (Komagataeibacter sucrofermentas) strains were pouched‑formed with hexagonal surface pattern required for reducing the formation of fibrotic tissue around devices, once they are implanted in soft tissues. Our findings revealed the effectiveness of the selected Komagataeibacter wild‑type strains in producing surface microstructured bacterial cellulose pouches for making biomedical devices

Candidate Acetic Acid Bacteria Strains for Levan Production

In this study, twelve strains of acetic acid bacteria (AAB) belonging to five different genera were tested for their ability to produce levan, at 70 and 250 g/L of sucrose concentration, respectively. The fructan produced by the bacterial strains was characterized as levan by NMR spectroscopy. Most of the strains produced levan, highlighting intra- and inter-species variability. High yield was observed for Neoasaia chiangmaiensis NBRC 101099 T, Kozakia baliensis DSM 14400 T and Gluconobacter cerinus DSM 9533 T at 70 g/L of sucrose. A 12-fold increase was observed for N. chiangmaiensis NBRC 101099 T at 250 g/L of sucrose concentration. Levan production was found to be affected by glucose accumulation and pH reduction, especially in Ko. baliensis DSM 14400 T. All the Gluconobacter strains showed a negative correlation with the increase in sucrose concentration. Among strains of Komagataeibacter genus, no clear effect of sucrose on levan yield was found. Results obtained in this study highlighted the differences in levan yield among AAB strains and showed interdependence between culture conditions, carbon source utilization, and time of incubation. On the contrary, the levan yield was not always related to the sucrose concentration