291 research outputs found
How to securely break into RBAC: the BTG-RBAC model
No full textAccess control models describe frameworks that dictate how subjects (e.g. users) access resources. In the Role-Based Access Control (RBAC) model access to resources is based on the role the user holds within the organization. Although flexible and easier to manage within large-scale authorization frameworks, RBAC is usually a static model where access control decisions have only two output options: Grant or Deny. Break The Glass (BTG) policies can be provided in order to break or override the access controls within an access control policy but in a controlled and justifiable manner. The main objective of this paper is to integrate BTG within the NIST/ANSI RBAC model in a transparent and secure way so that it can be adopted generically in any domain where unanticipated or emergency situations may occur. The new proposed model, called BTG-RBAC, provides a third decision option BTG. This allows break the glass policies to be implemented in any application without any major changes to either the application or the RBAC authorization infrastructure, apart from the decision engine. Finally, in order to validate the model, we discuss how the BTG-RBAC model is being introduced within a Portuguese healthcare institution where the legislation requires that genetic information must be accessed by a restricted group of healthcare professionals. These professionals, advised by the ethical committee, have required and asked for the implementation of the BTG concept in order to comply with the said legislation
Anthropogenic shift towards higher risk of flash drought over China
No full textFlash droughts refer to a type of droughts that have rapid intensification without sufficient early warning. To date, how will the flash drought risk change in a warming future climate remains unknown due to a diversity of flash drought definition, unclear role of anthropogenic fingerprints, and uncertain socioeconomic development. Here we propose a new method for explicitly characterizing flash drought events, and find that the exposure risk over China will increase by about 23% ± 11% during the middle of this century under a socioeconomic scenario with medium challenge. Optimal fingerprinting shows that anthropogenic climate change induced by the increased greenhouse gas concentrations accounts for 77% ± 26% of the upward trend of flash drought frequency, and population increase is also an important factor for enhancing the exposure risk of flash drought over southernmost humid regions. Our results suggest that the traditional drought-prone regions would expand given the human-induced intensification of flash drought risk.</p
A privacy preserving authorisation system for the cloud
No full textIn this paper we describe a policy based authorisation infrastructure that a cloud provider can run as an infrastructure service for its users. It will protect the privacy of users’ data by allowing the users to set their own privacy policies, and then enforcing them so that no unauthorised access is allowed to their data. The infrastructure ensures that the users’ privacy policies are stuck to their data, so that access will always be controlled by the policies even if the data is transferred between cloud providers or services. This infrastructure also ensures the enforcement of privacy policies which may be written in different policy languages by multiple authorities such as: legal, data subject, data issuer and data controller. A conflict resolution strategy is presented which resolves conflicts among the decisions returned by the different policy decision points (PDPs). The performance figures are presented which show that the system performs well and that each additional PDP only imposes a small overhead
Pockmark activity inferred from pore water geochemistry in shallow sediments of the pockmark field in southwestern Xisha Uplift, northwestern South China Sea
No full textA data-driven approach for ship-bridge collision candidate detection in bridge waterway
No full textThe consequences caused by bridge failures owing to the ship-bridge collision are always severe in terms of loss of life, economy, and environmental consequences to individuals and societies. The previous studies focused on the ship-bridge collision mainly concentrated on passive anti-collision, such as strengthening the bridge structure or setting anti-collision facilities. Compared with the previous research, the contribution of this work is to facilitate the reduction of collision risk of ship-bridge collision from the perspective of active anti-collision. A data-driven approach for ship-bridge collision candidate detection method in inland bridge waterways is proposed in this research. The approach is mainly divided into two steps: 1) The features (channel boundary, pier domain, and ship domain) of bridge waterways are identified using Kernel Density Estimation (KDE) method based on the historical AIS data; 2) Collision candidate detection with Velocity Obstacle (VO) method considering the identified features. This work can provide beneficial support for the ship-bridge active collision avoidance system.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Safety and Security Scienc
IMMM-SFA/URBAN_WHITE_ROOF_CESM2 test
No full text# Urban White Roof Experiments using CESM2
Repository containing driving scripts and model configuration to set up CESM2 simulations used for urban white roof experiments on the National Centre for Atmospheric Research (NCAR) high performance computing machine, Cheyenne.
The input datasets used for the CESM experiments are obtained from NCAR. All input data that the namelists refer are available on Cheyenne at the specified paths.
CESM/CLM5 release code (tag: release-cesm2.0.02) is available at http://www.cesm.ucar.edu/models/cesm2/release_download.html.
## Structure of this repository
---scripts | ---user_mods | ---namelists | --postprocessing
## Acknowledgment
U.S. Department of Energy (DOE), Office of Science, as part of research in Multi-Sector Dynamics, Earth and Environmental System Modeling Progra
Real-time collision risk based safety management for vessel traffic in busy ports and waterways
No full textRegional risk analysis and management of maritime accidents is one of the fundamental tasks for maritime safety management. With the heavy and complicated maritime traffic in the ports and waterways, accidents, especially ship collision accidents, have been continuously posing threats to the maritime transportation system. To achieve effective and prompt identification of collision risk and to facilitate the stakeholders such as Maritime Safety Administration, this paper proposes an integrated approach for regional collision risk analysis and maritime safety management in busy ports and waterways. Firstly, regional gridding is used to link accident data and traffic data based on geographical location; Secondly, the risk model based on accident data is established. The reliability of the accident risk model is verified by data feature analysis. Finally, non-accident critical events are mined from historical accident data and traffic data as surrogate indicators of collision accidents. A regional real-time risk model is developed for integrating the accident risk model and non-accident critical events risk model by using random forest. A case study in Shenzhen port indicates that the proposed collision risk model can identify high-risk areas and facilitates maritime safety management to improve the safety level of vessel traffic in these areas. In this paper, the regional grid is used to overcome the shortcomings of different scales between data, and a real-time risk model is established by combining accidents and traffic. The 15-year maritime collision accidents are used for collision risk modeling, which improves the performance of the model.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Safety and Security Scienc
IMMM-SFA-URBAN_WHITE_ROOF_CESM2
No full textUser namelist settings, code changes and driving scripts to set to CESM2 on NCAR Cheyenne for urban white roof experiments simulations
Towards real-time ship collision risk analysis: An improved R-TCR model considering target ship motion uncertainty
No full textCollision between ships is one of the major contributors to ship accidents. To facilitate the development of the real-time collision risk analysis model for collision avoidance, in this research, an improved Rule-aware Time-varying Collision risk Model is proposed, which considers the estimation of target ship motion and the corresponding uncertainty in the risk analysis process. To make the collision risk model more in line with the actual situation, ship maneuverability, the COLREGs, and good seamanship are considered and integrated into the framework of the TCR model. Firstly, the Gaussian process is used to predict the potential trajectories of the target ship. Secondly, the Probabilistic Velocity Obstacle (PVO) model is utilized to integrate the uncertainty of the target ship's motion into the collision risk model. The collision risk is therefore formulated as a ratio of available maneuvers leading to a collision to all available maneuvers. To verify the effectiveness of collision risk, two actual target ships and six groups of collision risk detection experiments under different encounter scenarios were carried out. Compared with the traditional collision risk index model and original R-TCR model, the collision risk detected by the Improved R-TCR model is closer to the actual situation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Safety and Security Scienc
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