scholarly journals An Extensible Automated Failure Localization Framework Using NetKAT, Felix, and SDN Traceroute

2019 ◽  
Vol 11 (5) ◽  
pp. 107 ◽  
Author(s):  
István Pelle ◽  
András Gulyás
Keyword(s):  
Formal Specification ◽  
Network Monitoring ◽  
Actual Behavior ◽  
Proof Of Concept ◽  
Policy Changes ◽  
External Threats ◽  
Human Effort ◽  
Types Of Information ◽  
Network Troubleshooting ◽  
Failure Localization

Designing, implementing, and maintaining network policies that protect from internal and external threats is a highly non-trivial task. Often, troubleshooting networks consisting of diverse entities realizing complex policies is even harder. Software-defined networking (SDN) enables networks to adapt to changing scenarios, which significantly lessens human effort required for constant manual modifications of device configurations. Troubleshooting benefits SDN’s method of accessing forwarding devices as well, since monitoring is made much easier via unified control channels. However, by making policy changes easier, the job of troubleshooting operators is made harder too: For humans, finding, analyzing, and fixing network issues becomes almost intractable. In this paper, we present a failure localization framework and its proof-of-concept prototype that helps in automating the investigation of network issues. Like a controller for troubleshooting tools, our framework integrates the formal specification (expected behavior) and network monitoring (actual behavior) and automatically gives hints about the location and type of network issues by comparing the two types of information. By using NetKAT (Kleene algebra with tests) for formal specification and Felix and SDN traceroute for network monitoring, we show that the integration of these tools in a single framework can significantly ease the network troubleshooting process.

scholarly journals Verification of HotStuff BFT Consensus Protocol With TLA+/TLC in an Industrial Setting

2021 ◽  
Vol 93 ◽  
pp. 01006
Author(s):  
Vladimir Kukharenko ◽  
Kirill Ziborov ◽  
Rafael Sadykov ◽  
Ruslan Rezin
Keyword(s):  
Formal Verification ◽  
Formal Specification ◽  
Fault Tolerant ◽  
Software Implementation ◽  
Actual Behavior ◽  
Smart Contracts ◽  
Consensus Protocol ◽  
Verification Methods ◽  
Formal Specification And Verification ◽  
Specification And Verification

The extent of formal verification methods applied in industrial projects has always been limited. The proliferation of distributed ledger systems (DLS), also known as blockchain, is rapidly changing the situation. Since the main area of DLSs’ application is the automation of financial transactions, the properties of predictability and reliability are critical for implementing such systems. The actual behavior of the DLS is largely determined by the chosen consensus protocol, which properties require strict specification and formal verification. Formal specification and verification of the consensus protocol is necessary but not sufficient. It is also required to ensure that the software implementation of the DLS nodes complies with this protocol. Finally, the verified software implementation of the protocol must run on a fairly reliable operating system. The financial focus of DLS application has also led to the emergence of the so-called smart contracts, which are an important part of the applied implementations of specific business processes based on DLSs. Therefore, the verifiability of smart contracts is also a critical requirement for industrial DLSs. In this paper, we describe an ongoing industrial project between a large Russian airline and three universities – Innopolis University (IU), Moscow Institute of Physics and Technology (MIPT) and Lomonosov Moscow State University (MSU). The main expected project result is a DLS for more flexible refueling of aircrafts, verified at least at the four technological levels described above. After brief project overview, we focus on our experience with the formal specification and verification of HotStuff, a leader-based fault-tolerant protocol that ensures reaching distributed consensus in the presence of Byzantine processes. The formal specification of the protocol is performed in the TLA+ language and then verified with a specialized TLC tool to verify models based on TLA+ specifications.

Multipartner military exercises may become flashpoints

2015 ◽  
Keyword(s):  
Foreign Minister ◽  
The United States ◽  
Policy Changes ◽  
Content Type ◽  
The Past ◽  
External Threats ◽  
Military Exercises ◽  
Russian President ◽  
Vladimir Putin ◽  
Do So

Significance The exercise was described by NATO as a "show of force", while the Dutch foreign minister referred to it as "a warning" to Russian President Vladimir Putin. Multinational military exercises have become more frequent over the past 25 years. The United States participates in dozens of exercises annually and spends billions of dollars to do so. However, there are significant questions over the utility and purpose of such multinational exercises, which serve both a practical function for the militaries involved, as well as a diplomatic signaling effect. Impacts Like BALTOPS, regular exercises will assume greater salience when their regional focus sees new external threats. This could prompt policy changes from adversaries, as they attempt to respond to the exercises. As a result, exercises designed to deter may risk escalating tensions.

scholarly journals Looking for Inspiration: Understanding the Information Evaluation and Seeking Behavior of Novice Designers During Creative Idea Generation

2019 ◽  
Vol 1 (1) ◽  
pp. 1793-1802
Author(s):  
Nicole Damen ◽  
Christine Toh
Keyword(s):  
Information Seeking ◽  
Idea Generation ◽  
Actual Behavior ◽  
Generation Process ◽  
Design Information ◽  
Perceived Utility ◽  
Seeking Behavior ◽  
Novice Designers ◽  
Types Of Information ◽  
Information Framework

AbstractInformation usage is a key aspect of creative cognition and has been shown to influence design outcomes. The goal of this study was to investigate the information seeking behavior of student designers while validating a previously developed “Typology of Design Information” framework. Participants were asked to use and evaluate pieces of information during the idea generation process. Results show a discrepancy between the information that participants naturally sought out and their perceived utility (helpfulness) of the information. However, individually significant relationships between perceived utility and behavior were found with features generated by participants, suggesting that even though participants' perception of the utility of information pieces and their actual behavior are not related, both constructs have an identifiable influence on design outcomes. This study advances the Typology of Design Information framework by empirically exploring the link between the types of information used by novice designers and the ideas generated, and it illustrates that participants employ complex cognitive behavior when engaging with design information to generate novel ideas.

scholarly journals Organizing knowledge to enable faster data interpretation in COVID-19 research

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 703
Author(s):  
Joseph Hearnshaw ◽  
Marco Brandizi ◽  
Ajit Singh ◽  
Chris Rawlings ◽  
Keywan Hassani-Pak
Keyword(s):  
Risk Factors ◽  
Clinical Trials ◽  
Data Interpretation ◽  
Research Data ◽  
Knowledge Graph ◽  
Biomedical Data ◽  
Drug Side Effects ◽  
Proof Of Concept ◽  
Biological Concepts ◽  
Types Of Information

Enormous volumes of COVID-19 research data have been published and this continues to increase daily. This creates challenges for researchers to interpret, prioritize and summarize their own findings in the context of published literature, clinical trials, and a multitude of databases. Overcoming the data interpretation bottleneck is vital to help researchers to be more efficient in their quest to identify COVID-19 risk factors, potential treatments, drug side-effects, and much more. As a proof of concept, we have organized and integrated a range of COVID-19 and human biomedical data and literature into a knowledge graph (KG). Here we present the datasets we have integrated so far and the content of the KG which consists of 674,969 biological concepts and over 1.6 million relationships between them. The COVID-19 KG is available via KnetMiner, an interactive online platform for gene discovery and knowledge mining, or via RDF and Neo4j graph formats which can be searched programmatically through SPARQL and Cypher endpoints. KnetMiner is a road mapped ELIXIR UK service. We hope this integrated resource will enable faster data interpretation and discovery of linkages between genes, drugs, diseases and many more types of information relating to COVID-19.

scholarly journals InnoChain: a Distributed Ledger for Industry with Formal Verification on all Implementation Levels

2020 ◽  
Vol 27 (4) ◽  
pp. 454-471
Author(s):  
Vladimir Aleksandrovich Kukharenko ◽  
Kirill Viktorovich Ziborov ◽  
Rafael Faritovich Sadykov ◽  
Alexandr Vladimirovich Naumchev ◽  
Ruslan Maratovich Rezin ◽  
...  
Keyword(s):  
Formal Verification ◽  
Formal Specification ◽  
Fault Tolerant ◽  
Software Implementation ◽  
Actual Behavior ◽  
Consensus Protocol ◽  
Distributed Ledger ◽  
Verification Methods ◽  
Formal Specification And Verification ◽  
Specification And Verification

The extent of formal verification methods applied to industrial projects has always been limited. The proliferation of distributed ledger systems (DLS), also known as blockchain, is rapidly changing the situation. Since the main area of DLSs' application is the automation of financial transactions, the properties of predictability and reliability are critical for implementing such systems. The actual behavior of the DLS is determined by the chosen consensus protocol, which properties require strict specification and formal verification. Formal specification and verification of the consensus protocol is necessary but not sufficient. It is required to ensure that the software implementation of the DLS nodes complies with this protocol. The verified software implementation of the protocol must run on a fairly reliable operating system. The so-called “smart contracts”, which are an important part of the applied implementations of specific business processes based on DLSs, must be verifiable as well. In this paper, we describe an ongoing industrial project that will result in a DLS verified at least at the four technological levels described above. We then share our experience with the formal specification and verification of HotStuff, a leader-based fault-tolerant protocol that ensures reaching distributed consensus in the presence of Byzantine processes.

scholarly journals Generating a Visual Map of the Crane Workspace Using Top-View Cameras for Assisting Operation

2020 ◽  
Vol 32 (2) ◽  
pp. 409-421
Author(s):  
Yu Wang ◽  
Hiromasa Suzuki ◽  
Yutaka Ohtake ◽  
Takayuki Kosaka ◽  
Shinji Noguchi ◽  
...  
Keyword(s):  
Mental Workload ◽  
Proof Of Concept ◽  
Limited Information ◽  
Location Error ◽  
Construction Sites ◽  
Image Processing Techniques ◽  
Types Of Information ◽  
Processing Techniques ◽  
Top View ◽  
Blind Spots

All terrain cranes often work in construction sites. Blind spots, limited information, and high mental workload are problems encountered by crane operators. A top-view camera mounted on the boom head offers a valuable perspective on the workspace that can help eliminate blind spots and provide the basis for assisting operation. In this study, a visual 2D map of a crane workspace is generated from images captured by a top-view camera. Various types of information can be overlaid on this visual 2D map to assist the operator, such as recording the operation and projecting the boom head’s expected path through the workspace. Herein, the process of generating a visual map by stitching and locating the boom head trajectory in that visual map is described. Preliminary proof-of-concept tests show that a precise map and projected trajectories can be generated via image-processing techniques that discriminate foreground objects from the scene below the crane. The location error is analyzed and verified to confirm its applicability. These results show a way to help the operator make more precise operation easily and reduce the operator’s mental workload.

scholarly journals The KB paradigm and its application to interactive configuration

2016 ◽  
Vol 17 (1) ◽  
pp. 91-117 ◽  
Author(s):  
PIETER VAN HERTUM ◽  
INGMAR DASSEVILLE ◽  
GERDA JANSSENS ◽  
MARC DENECKER
Keyword(s):  
Problem Solving ◽  
Knowledge Base ◽  
Formal Specification ◽  
Domain Knowledge ◽  
Formal Language ◽  
Real Life ◽  
Important Class ◽  
Proof Of Concept ◽  
Separation Of Concerns ◽  
Multiple Forms

AbstractThe knowledge base (KB) paradigm aims to express domain knowledge in a rich formal language, and to use this domain knowledge as a KB to solve various problems and tasks that arise in the domain by applying multiple forms of inference. As such, the paradigm applies a strict separation of concerns between information and problem solving. In this paper, we analyze the principles and feasibility of the KB paradigm in the context of an important class of applications: interactive configuration problems. In interactive configuration problems, a configuration of interrelated objects under constraints is searched, where the system assists the user in reaching an intended configuration. It is widely recognized in industry that good software solutions for these problems are very difficult to develop. We investigate such problems from the perspective of the KB paradigm. We show that multiple functionalities in this domain can be achieved by applying different forms of logical inferences on a formal specification of the configuration domain. We report on a proof of concept of this approach in a real-life application with a banking company.

High-Voltage Scanning Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 6-7
Author(s):  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Wave Optics ◽  
Contrast Effects ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission ◽  
Types Of Information ◽  
Voltage Scanning

The comparison of scanning transmission electron microscopy (STEM) with conventional transmission electron microscopy (CTEM) can best be made by means of the Reciprocity Theorem of wave optics. In Fig. 1 the intensity measured at a point A’ in the CTEM image due to emission from a point B’ in the electron source is equated to the intensity at a point of the detector, B, due to emission from a point A In the source In the STEM. On this basis it can be demonstrated that contrast effects In the two types of instrument will be similar. The reciprocity relationship can be carried further to include the Instrument design and experimental procedures required to obtain particular types of information. For any. mode of operation providing particular information with one type of microscope, the analagous type of operation giving the same information can be postulated for the other type of microscope. Then the choice between the two types of instrument depends on the practical convenience for obtaining the required Information.

Direct measurement of electron-diffraction-pattern intensities using an energy loss spectrometer

1989 ◽  
Vol 47 ◽  
pp. 668-669
Author(s):  
A. G. Jackson ◽  
M. Rowe
Keyword(s):  
Thermal Effects ◽  
Dynamic Range ◽  
Scattering Amplitude ◽  
Dynamical Theory ◽  
Site Symmetry ◽  
Proof Of Concept ◽  
Parallel Acquisition ◽  
Kinematic Approximation ◽  
Speed Up ◽  
Structure Calculations

Diffraction intensities from intermetallic compounds are, in the kinematic approximation, proportional to the scattering amplitude from the element doing the scattering. More detailed calculations have shown that site symmetry and occupation by various atom species also affects the intensity in a diffracted beam. [1] Hence, by measuring the intensities of beams, or their ratios, the occupancy can be estimated. Measurement of the intensity values also allows structure calculations to be made to determine the spatial distribution of the potentials doing the scattering. Thermal effects are also present as a background contribution. Inelastic effects such as loss or absorption/excitation complicate the intensity behavior, and dynamical theory is required to estimate the intensity value.The dynamic range of currents in diffracted beams can be 104or 105:1. Hence, detection of such information requires a means for collecting the intensity over a signal-to-noise range beyond that obtainable with a single film plate, which has a S/N of about 103:1. Although such a collection system is not available currently, a simple system consisting of instrumentation on an existing STEM can be used as a proof of concept which has a S/N of about 255:1, limited by the 8 bit pixel attributes used in the electronics. Use of 24 bit pixel attributes would easily allowthe desired noise range to be attained in the processing instrumentation. The S/N of the scintillator used by the photoelectron sensor is about 106 to 1, well beyond the S/N goal. The trade-off that must be made is the time for acquiring the signal, since the pattern can be obtained in seconds using film plates, compared to 10 to 20 minutes for a pattern to be acquired using the digital scan. Parallel acquisition would, of course, speed up this process immensely.

Structural dynamics of P-type ATPase ion pumps

2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
New Technologies ◽  
Atp Hydrolysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Dynamics Simulations ◽  
Types Of Information ◽  
P Type

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.

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