Distributed cyber-attack isolation for large-scale interconnected systems

This work addresses the problem of cyber-attack isolation within a distributed diagnosis architecture for large-scale interconnected systems. Considering a distributed control architecture, malicious agents are capable of compromising the data exchanged between distributed controllers. Building on a distributed detection strategy existent in literature, in this paper we propose a distributed isolation algorithm to identify the attacked communication link. After presenting the isolation algorithm, we give a necessary and a sufficient condition for isolation to occur, relating to the structure of the physical interconnection matrices. We demonstrate the effectiveness of the proposed technique through numerical simulations

A Distributed Approach for the Detection of Covert Attacks in Interconnected Systems with Stochastic Uncertainties

The design of a distributed architecture for the detection of covert attacks in interconnected Cyber-Physical Systems is addressed in this paper, in the presence of stochastic uncertainties. By exploiting communication between neighbors, the proposed scheme allows for the detection of covert attacks that are locally stealthy. The proposed methodology adopts a decentralized filter, jointly estimating the local state and the aggregate effect of the physical interconnections, and uses the communicated estimates to obtain an attack-sensitive residual. We derive some theoretical detection properties for the proposed architecture, and present numerical simulations

A distributed attack detection method for multi-agent systems governed by consensus-based control

The paper considers the problem of detecting cyber-attacks occurring in communication networks for distributed control schemes. A distributed methodology is proposed to detect the presence of malicious attacks aimed at compromising the stability of large-scale interconnected systems and multi-agent systems governed by consensus-based controllers. Only knowledge of the local model is required. The detectability properties of the proposed method are analyzed. A class of undetectable attacks is identified. Preliminary simulation results show the effectiveness of the proposed approach

Limits on the quiescent radio emission from the black hole binaries GRO J1655-40 and XTE J1550-564

We present the results of radio observations of the black hole binaries GRO J1655-40 and XTE J1550-564 in quiescence, with the upgraded Australia Telescope Compact Array. Neither system was detected. Radio flux density upper limits (3 sigma) of 26 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for GRO J1655-40, and 1.4 mJy (at 1.75 GHz), 27 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for XTE J1550-564 were measured. In conjunction with quasi-simultaneous Chandra X-ray observations (in the case of GRO J1655-40) and Faulkes Telescope optical observations (XTE J1550-564) we find that these systems provide the first evidence of relatively `radio quiet' black hole binaries at low luminosities; indicating that the scatter observed in the hard state X-ray:radio correlation at higher luminosities may also extend towards quiescent levels.Comment: Accepted for publication in MNRA

An Egyptian green schist palette and an amazonite gemstone from the “Palace of the Copper Axes” at Batrawy, Jordan

The exploration of the “Palace of the Copper Axes”, the Early Bronze Age III palace of the easternmost city of Southern Levant during the 3rd millennium BC, was resumed in 2018, during the 14th season of excavation at Khirbet al-Batrawy in north-central Jordan, and completed in 2019. In the entrance hall of the palace, a square space with ceilings supported by four pillars, an Egyptian green schist palette, a cyan gemstone of amazonite and a pierced bead of fluorapatite were found buried under the destruction layer, while a barrel-shaped carnelian bead from Mesopotamia was found in the destruction layer just outside the Eastern Pavilion of the palace. These finds again testify to the inclusion of the palace and the city into a wide international trade network and its special connections with Pharaonic Egypt

Distributed Cyber-Attack Detection in the Secondary Control of DC Microgrids

The paper considers the problem of detecting cyber-attacks occurring in communication networks typically used in the secondary control layer of DC microgrids. The proposed distributed methodology allows for scalable monitoring of a microgrid and is able to detect the presence of data injection attacks in the communications among Distributed Generation Units (DGUs) - governed by consensus-based control - and isolate the communication link over which the attack is injected. Each local attack detector requires limited knowledge regarding the dynamics of its neighbors. Detectability properties of the method are analyzed, as well as a class of undetectable attacks. Some results from numerical simulation are presented to demonstrate the effectiveness of the proposed approach

A new dedicated clinic for HCWs' counseling and vaccination: experience of an academic hospital

Abstract Issue Despite low healthcare workers (HCWs) vaccination coverage being a risk for hospital outbreaks, vaccine hesitancy is not unusual among HCWs. In Italy vaccinations are strongly recommended for HCWs, but there are few occasions for a dedicated counseling. Aim of the study is to evaluate the effectiveness of a new vaccination service in the academic hospital of Udine (northern Italy) in tackling vaccine hesitancy among HCWs. Description of the problem Available data on HCWs specific antibody titers revealed that in high-risk units, 25% of HCWs were certainly unprotected for at least 1/6 of the vaccine preventable diseases (VPDs): measles, rubella, mumps, varicella, pertussis, hepatitis B; only varicella coverage reached the herd immunity target. Periodic occupational health visit was the only moment to screen for VPDs protection and suggest vaccination, but the following inconvenient procedure of HCWs contacting the vaccination office outside the hospital, often lead to delays or loss. In order to improve vaccination adherence, since June 2019 a dedicated clinic has been set up inside the hospital, making vaccination counseling and administration available every two weeks, with appointments directly given by the occupational doctor. Results From June 2019 to February 2020, a total of 362 appointments were booked for the dedicated vaccination clinic, 69.7% of which actually took place as 252 HCWs actually accessed the service. Hours dedicated to the service activity were 76 hours, distributed over 19 days. Administered vaccination were 322, including 107 MMR (measles, rubella, mumps), 4 MMRV (MMR+varicella), 20 varicella, 64 hepatitis B, 127 DTPa (diphtheria, tetanus, pertussis). Lessons Making the access to vaccination more convenient in term of service location within the hospital and giving the appointment when performing the occupational health visit seems to be helpful in filling the VPDs protection among HCWs gap. Key messages Monitoring immunological status of HCWs and promoting vaccination at occupational health visit would sustain herd immunity protection for susceptible individuals in healthcare settings. The dedicated hospital vaccination clinic and the effective procedure of giving the appointment during the occupational health visit could be helpful in improving HCWs vaccine adherence

The Spectrum of the Black Hole X-ray Nova V404 Cygni in Quiescence as Measured by XMM-Newton

We present XMM observations of the black hole X-ray nova V404 Cygni in quiescence. Its quiescent spectrum can be best fitted by a simple power-law with slope 2. The spectra are consistent with that expected for the advection-dominated accretion flow (ADAF). V404 Cyg was roughly equal in luminosity compared to the previous observation of Chandra. We see variability of a factor of 4 during the observation. We find no evidence for the presence of fluorescent or H-like/He-like iron emission, with upper limits of 52 eV and 110 eV respectively. The limit on the fluorescent emission is improved by a factor of 15 over the previous estimate, and the restriction on H-like/He-like emission is lower than predicted from models by a factor of roughly 2.Comment: 6 pages, 7 figures, ApJ accepte