Extending the Real-Time Maude Semantics of Ptolemy to Hierarchical DE Models

This paper extends our Real-Time Maude formalization of the semantics of flat Ptolemy II discrete-event (DE) models to hierarchical models, including modal models. This is a challenging task that requires combining synchronous fixed-point computations with hierarchical structure. The synthesis of a Real-Time Maude verification model from a Ptolemy II DE model, and the formal verification of the synthesized model in Real-Time Maude, have been integrated into Ptolemy II, enabling a model-engineering process that combines the convenience of Ptolemy II DE modeling and simulation with formal verification in Real-Time Maude.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

Smart detection and prevention procedure for DoS attack in MANET

A self-organized wireless communication short-lived network containing collection of mobile nodes is mobile ad hoc network (MANET). The mobile nodes communicate with each other by wireless radio links without the use of any pre-established fixed communication network infrastructure or centralized administration, such as base stations or access points, and with no human intervention. In addition, this network has potential applications in conference, disaster relief, and battlefield scenario, and have received important attention in current years. There is some security concern that increases fear of attacks on the mobile ad-hoc network. The mobility of the NODE in a MANET poses many security problems and vulnerable to different types of security attacks than conventional wired and wireless networks. The causes of these issues are due to their open medium, dynamic network topology, absence of central administration, distributed cooperation, constrained capability, and lack of clear line of defense. Without proper security, mobile hosts are easily captured, compromised, and attacked by malicious nodes. Malicious nodes behavior may deliberately disrupt the network so that the whole network will be suffering from packet losses. One of the major concerns in mobile ad-hoc networks is a traffic DoS attack in which the traffic is choked by the malicious node which denied network services for the user. Mobile ad-hoc networks must have a safe path for transmission and correspondence which is a serious testing and indispensable issue. So as to provide secure communication and transmission, the scientist worked explicitly on the security issues in versatile impromptu organizations and many secure directing conventions and security measures within the networks were proposed. The goal of the work is to study DoS attacks and how it can be detected in the network. Existing methodologies for finding a malicious node that causes traffic jamming is based on node’s retains value. The proposed approach finds a malicious node using reliability value determined by the broadcast reliability packet (RL Packet). In this approach at the initial level, every node has zero reliability value, specific time slice, and transmission starts with a packet termed as reliability packet, node who responded properly in specific time, increases its reliability value and those nodes who do not respond in a specific time decreases their reliability value and if it goes to less than zero then announced that it’s a malicious node. Reliability approach makes service availability and retransmission time

Macroalgae as an eco-friendly and successful green technology for the removal of crystal violet from synthetic and real wastewater

Crystal violet (CV) is one of the water pollutants that can cause potential harm to living beings and the environment. Different methods are applied for the removal of CV from wastewater, however, a cheap and environmentally friendly way is preferred. In this study, Hormophysa triquetra (HT) and its silver-modified form (AgHT) were used for the removal of CV from synthetic and real wastewater. Both physical and chemical characterizations of HT and AgHT were carried out using scanning electron microscopy – energy dispersive X-ray analysis (SEM-EDX), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), zeta potential (ζ-potential), and Brunauer-Emmet-Teller (BET) analysis. Different parameters such as pH, temperature, and concentration were studied for the adsorption process. The optimum pH of the adsorption process was 6 with a maximum adsorption capacity of 181.8 mg/g for HT and 312.5 mg/g for AgHT at 45◦C. The best-fitted adsorption isotherm model was the Langmuir model based on the correlation coefficient (R2) however; the chi-square (χ2) analysis indicated the Freundlich model to be the best-fit model. Moreover, the thermodynamics studies indicated a spontaneous and endothermic reaction with HT and the reverse with AgHT. The main functional groups contributing to the adsorption of CV on the adsorbents involve carboxyl, hydroxyl, carbonyl groups, and aromatic rings. The adsorbent removed more than 98 % of CV from real wastewater with AgHT being more efficient than HT. Desorption studies indicated that desorption agents such as NaOH and HCl reduced the electrostatic interactions between the adsorbate and the adsorbent, thereby regenerating the adsorbent. This study proves the use of naturally abundant and available macroalgae as an eco-friendly and successful green technology for the removal of CV from real wastewater

Design and numerical analysis of CIGS-based solar cell with V2O5 as the BSF layer to enhance photovoltaic performance

Copper indium gallium selenide (CIGS)-based solar cells have exhibited greater performance than the ones utilizing cadmium telluride (CdTe) or hydrogenated amorphous silicon (a-Si: H) as the absorber. CIGS-based devices are more efficient, considering their device performance, environmentally benign nature, and reduced cost. In this article, we proposed a potential CIGS-absorber-based solar cell with an FTO/ZnSe/CIGS/V2O5/Cu heterostructure, with a V2O5 back-surface field (BSF) layer, SnO2:F (FTO) window layer, and ZnSe buffer layer. Using the solar cell capacitance simulator one-dimensional simulation software, the effects of the presence of the BSF layer, the thickness, bulk defect density, and acceptor density of the absorber layer, buffer layer thickness, interfacial defect density, device resistance, and operating temperature on the open-circuit voltage, short-circuit current, fill factor, and efficiency, as well as on the quantum efficiency and recombination and generation rate, of the device have been explored in detail. The simulation results revealed that only a 1 μm-thick-CIGS absorber layer with V2O5 BSF and ZnSe buffer layers in this structure offers an outstanding efficiency of 31.86% with a VOC of ∼0.9 V. Thus, these outcomes of the CIGS-based proposed heterostructure provide an insightful pathway for fabricating high-efficiency solar cells with performance more promising than the previously reported conventional designs