Network protocols are often analyzed using simulations. We demonstrate how to extend such simulations to check propositions expressing safety properties of network event traces in an extended form of linear temporal logic. Our technique uses the NS simulator together with a component of the MaC system to provide a uniform framework. We demonstrate its effectiveness by analyzing simulations of the Ad Hoc On-Demand Distance Vector (AODV) routing protocol for packet radio networks. Our analysis finds violations of significant properties and we discuss the faults that cause them. Novel aspects of our approach include modest integration costs with other simulation objectives such as performance evaluation, greatly increased flexibility in specifying properties to be checked and techniques for analyzing complex traces of alarms raised by the monitoring software. KeywordsVerisim, formal analysis, network, simulation, testing, routing, NS, MaC, AODV, temporal logic, ad hoc networks, packet radio, tuning, population abstraction, packet-type abstraction This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.An earlier, conference version of this paper may be found at http://repository.upenn.edu/cis_papers/84/. Abstract-Network protocols are often analyzed using simulations. We demonstrate how to extend such simulations to check propositions expressing safety properties of network event traces in an extended form of linear temporal logic. Our technique uses the NS simulator together with a component of the MaC system to provide a uniform framework. We demonstrate its effectiveness by analyzing simulations of the Ad Hoc On-Demand Distance Vector (AODV) routing protocol for packet radio networks. Our analysis finds violations of significant properties and we discuss the faults that cause them. Novel aspects of our approach include modest integration costs with other simulation objectives such as performance evaluation, greatly increased flexibility in specifying properties to be checked and techniques for analyzing complex traces of alarms raised by the monitoring software. Author(s)Karthikeyan
Ion current rectification (ICR), diodelike behavior in surface-charged nanopores, shows promise in the design of delivery probes for manipulation of neural networks as it can solve diffusive leakages that might be critical in clinical and research applications. However, it has not been achieved because ICR has restrictions in nanosized dimension and low electrolyte concentration, and rectification direction is inappropriate for delivery. Herein, we present a polyelectrolyte gel-filled (PGF) micropipette harnessing inverted ICR as a delivery probe, which quantitatively transports glutamate to stimulate primary cultured neurons with high efficiency while minimizing leakages. Since the gel works as an ensemble of numerous surface-charged nanopores, the current is rectified in the micro-opening and physiological environment. By extending the charge-selective region using the gel, inverted ICR is generated, which drives outward deliveries of major charge carriers. This study will help in exploring new aspects of ICR and broaden its applications for advanced chemical delivery.
Authentic leadership has recently become a matter of significant interest in the fields of politics, economics, society, and culture as well as leadership. This study examines the effects of authentic leadership on employees' well-being and determines whether relational cohesion can regulate the effects that occur between the two. In this regard, the study conducted empirical research with 950 employees of Korea's leading manufacturers, public enterprises, and financial firms. The results demonstrated that team leaders' authentic leadership increased employees' eudaimonic well-being but did not significantly affect hedonic well-being. However, when there was a high perception of relational cohesion that showed collaborative and integrated relationships with team members, the effects of authentic leadership on employees' well-being were significantly positive, thereby verifying the interaction effect between the two. In particular, this result stemmed from controlling the effects of transformational and ethical leadership, both of which represent conventional forms of leadership, and is thus significant. Finally, the study provided in-depth discussions on the implications of the research results for organizations and teams.
It is important but challenging to elucidate the electrochemical reaction mechanisms of organic compounds using electroanalytical methods. Particularly, a rapid and straightforward method that provides information on reaction intermediates or other key electrochemical parameters may be useful. In this work, we exploited the advantages of classic thin-layer electrochemistry to develop a thin-layer electroanalysis microchip (TEAM). The TEAM provided better-resolved voltammetric peaks than under semi-infinite diffusion conditions owing to its small height. Importantly, rapid and accurate determination of the number of electrons transferred, n, was enabled by mechanically confining the microliter-scale volume analyte at the electrode, while securing ionic conduction using polyelectrolyte gels. The performance of the TEAM was validated using voltammetry and coulometry of standard redox couples. Utilizing the TEAM, a (spectro)electrochemical analysis of FM 1–43, an organic dye widely used in neuroscience, was successfully performed. Moreover, the TEAM was applied to study the electrochemical oxidation mechanism of pivanilides and alkyltrifluoroborate salts with different substituents and solvents. This work suggests that TEAM is a promising tool to provide invaluable mechanistic information and promote the rational design of electrosynthetic strategies.
We describe the Monitoring and Checking (MaC) framework which provides assurance on the correctness of an execution of a real-time system at run-time. Monitoring is performed based on a formal specification of system requirements. MaC bridges the gap between formal specification, which analyzes designs rather than implementations, and testing, which validates implementations but lacks formality. An important aspect of the framework is a clear separation between implementation-dependent description of monitored objects and high-level requirements specification. Another salient feature is automatic instrumentation of executable code The paper presents an overview of the framework. languages to express monitoring scripts and requirements, and a prototype implementation of MaC targeted at systems implemented in Java. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it. Author(s)Moonjoo AbstractWe describe the Monitoring and Checking MaC framework which provides assurance on the correctness of an execution of a real-time system at runtime. Monitoring is performed based on a formal speci cation of system requirements. MaC bridges the gap between formal speci cation, which analyzes designs rather than implementations, and testing, which validates implementations but lacks formality. An important aspect of the framework is a clear separation between implementation-dependent description of monitored objects and high-level requirements speci cation. Another salient feature i s automatic instrumentation of executable code.The paper presents an overview of the framework, languages to express monitoring scripts and requirements, and a prototype implementation of MaC targeted at systems implemented in Java.
Carbon-based nanomaterials are renowned for their exceptional properties, making them propitious candidates for oxygen reduction reaction (ORR) electrocatalysis. However, their intrinsic activity is often challenging to investigate unambiguously with conventional methodologies due to the inherent complexities of such systems and the material itself. Zooming into the material and gaining electrochemical information with high resolution is a way to get rid of many experimental factors that influence the catalytic activity in macro-scale measurements.Herein, we employ nano-scale scanning electrochemical cell microscopy (SECCM) to investigate individual catalyst agglomerates with and without Nafion content. The intrinsic ORR activity of the catalyst was unravelled by using a unique approach of normalizing the data of all measured points by their distinctive electrochemical surface area (ECSA). When coupling with scanning electron microscopy (SEM), the structure and morphology of the catalytically active agglomerates were visualized.
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