115,168 research outputs found
A New S-Box Design System for Data Encryption Using Artificial Bee Colony Algorithm
No full textSecuring digital image data is a key concern in today’s information-driven society. Effective encryption techniques are required to protect sensitive image data, with the Substitution-box (S-box) often playing a pivotal role in many symmetric encryption systems. This study introduces an innovative approach to creating S-boxes for encryption algorithms. The proposed S-boxes are tested for validity and non-linearity by incorporating them into an image encryption scheme. The nonlinearity measure of the proposed S-boxes is 112. These qualities significantly enhance its resistance to common cryptographic attacks, ensuring high image data security. Furthermore, to assess the robustness of the S-boxes, an encryption system has also been proposed and the proposed S-boxes have been integrated into the designed encryption system. To validate the eectiveness of the proposed encryption system, a comprehensive security analysis including brute force attack and histogram analysis has been performed. In addition, to determine the level of security during the transmission and storage of digital content, the encryption system’s Number of Pixel Change Rate (NPCR), and Unified Averaged Changed Intensity (UACI) are calculated. The results indicate a 99.71% NPCR and 33.51% UACI. These results demonstrate that the proposed S-boxes offer a significant level of security for digital content throughout its transmission and storage
Comparison of signalized junction control strategies using individual vehicle position data
No full textThis paper is concerned with the development of control strategies for urban signalized junction that can make use of individual vehicle position data from localization probes on board the vehicles. Strategy development involves simulating the behaviour of vehicles as they negotiate junctions controlled by prototype strategies and evaluating performance. Two strategies are discussed in this paper, a simple auctioning agent strategy and an extended auctioning agent strategy where a machine learning approach is used to enable agents to be trained by a human expert to improve performance. The performance of these two strategies are compared with each other and with the MOVA algorithm in simulated tests. The results show that auctioning agents using individual vehicle position data can out perform MOVA, but that this performance can be improved further still by using learning auctioning agents trained by a human expert
Signal control using vehicle localization probe data
No full textThis paper presents a simulation test bed and methodology for evaluating urban signalized junction control algorithms that use localization probe data from all vehicles in the local area. The simulator is based on SIAS Paramics micro-simulation software with bespoke software modules built on top for automatic network generation, localization data processing and signal control. Localization algorithms tested use a hierarchical structure of auctioning agents. Early tests of control algorithms on an isolated signalized junction indicate performance that compares favourably with the MOVA algorithm using inductive loop data.<br/
Antarctica SSA and broadband albedo austral summer 2022/2023 from Sentinel-3’s OLCI and pySICEv1.6
No full textTimespan
15 Oct, 2022 to 28 Feb 2023
Description
0.5 km daily SSA and broadband albedo. Albedo is 'spherical', meaning 'white sky' or 'diffuse', i.e. does not depend on the position of the sun. Data format is NetCDF. Embedded are attributes. We suggest using xarray to read the data files.
pySICEv1.6 is available at https://github.com/GEUS-SICE/pySICE/releases/tag/v1.6
Related Publications
Kokhanovsky, A., M. Lamare, O. Danne, C. Brockmann, M. Dumont, G. Picard, L. Arnaud, V. Favier, B. Jourdain, E. Lemeur, B. Di Mauro, T Aoki, M. Niwano, V. Rozanov, S. Korkin, S. Kipfstuhl, J. Freitag, M. Hoerhold, A. Zuhr, D. Vladimirova, A.-K. Faber, H.C. Steen-Larsen, S. Wahl, J.K. Andersen, B. Vandecrux, D. van As, K.D. Mankoff, M. Kern, E. Zege, and J.E. Box, Retrieval of snow and ice properties from the Sentinel-3 Ocean and Land Colour Instrument, Remote Sensing, Remote Sens. 2019, 11(19), 2280; https://doi.org/10.3390/rs11192280
Kokhanovsky, A.; Box, J.E.; Vandecrux, B.; Mankoff, K.D.; Lamare, M.; Smirnov, A.; Kern, M. The Determination of Snow Albedo from Satellite Measurements Using Fast Atmospheric Correction Technique. Remote Sens. 2020, 12, 234. https://doi.org/10.3390/rs12020234
Arioli, S., Picard, G., Arnaud, L., and Favier, V.: Dynamics of the snow grain size in a windy coastal area of Antarctica from continuous in situ spectral-albedo measurements, The Cryosphere, 17, 2323–2342, https://doi.org/10.5194/tc-17-2323-2023, 2023.
Vandecrux, B.; Box, J.E.; Wehrlé, A.; Kokhanovsky, A.A.; Picard, G.; Niwano, M.; Hörhold, M.; Faber, A.-K.; Steen-Larsen, H.C. The Determination of the Snow Optical Grain Diameter and Snowmelt Area on the Greenland Ice Sheet Using Spaceborne Optical Observations. Remote Sens. 2022, 14, 932. https://doi.org/10.3390/rs14040932
Questions?
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New pySICE versions
Find the latest version of pySICE here: https://github.com/GEUS-SICE/pySICE
For example pySICEv2.0 described in
Kokhanovsky, A., Vandecrux, B., Wehrlé, A., Danne, O., Brockmann, C., and Box, J. E.: An improved retrieval of snow and Ice properties using spaceborne OLCI/S-3 spectral reflectance measurements: Updated atmospheric correction and snow impurity load estimation, Remote Sens. (Basel), 15, 77, https://doi.org/10.3390/rs15010077, 2022.
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A new fast nanoparticle spectrometer for concentration and size distribution identification
No full textComparison of signalized junction control strategies that use localization probe data
No full textThis paper presents a simulation test bed and a methodology for evaluating urban signalized junction control algorithms that use localization probe data from all vehicles in the local area. The simulator is based on SIAS Paramics microsimulation software with bespoke software modules built on top for automatic network generation, localization data processing and signal control. Also presented are results from tests carried out using the simulation test bed to evaluate localization strategies. The tested strategies use a hierarchical structure of auctioning agents. Results from tests on an isolated signalized junction indicate that the performance of the auctioning agent algorithms compare favourably with the MOVA algorithm using inductive loop data. Results are also presented for tests on a twin junction where strategies are synchronized. These show a significant improvement in performance through synchronization
Construction of a Novel S-Box Based on a Compound Hénon–Baker Map
No full textConstructing S-boxes with strong cryptographic properties is critical to the security and effectiveness of modern cryptographic systems. We develop an 8×8 S-box by compounding the two-dimensional Hénon map with a one-step Baker map. We iterate the Hénon map 256 times, normalize to , apply one Baker step to intensify mixing, sort to obtain a permutation, and refine it via a lightweight hill-climbing swap strategy. As applications, we assess robustness using standard criteria—nonlinearity (NL), strict avalanche criterion (SAC), bit independence criterion (BIC), linear probability (LP), and differential probability (DP), and validate the S-box within an image encryption scheme on standard grayscale images (Lena, Baboon, Cameraman). Comparative analysis against S-boxes shows that the proposed S-box is cryptographically robust and suitable for integration into contemporary systems. Our best results are as follows: ciphertext entropy 7.9969–7.9972; adjacent-pixel correlations to 0.00108; contrast 10.4519–10.5350; energy 0.01564–0.01565; homogeneity 0.3891–0.3895; and SAC = 0.4968; BIC-NL = 103.7; BIC-SAC = 0.5007; LP = 0.14062; DP = 0.0469 with Boolean-function nonlinearity 108–110
Determining rail network accessibility
No full textThe usual representation of optimal path finding problems within transport networks is focused on well established algorithms for identifying the optimal path (or set of paths) between two specific network nodes. When the required solution is the identification of the optimal route between every possible pair of nodes in the network however, these algorithms are inefficient.The Floyd-Warshall algorithm provides an efficient way to compare all possible paths through each pair of nodes more efficiently, requiring only N3 comparisons for a network of N nodes. To illustrate the potential of this approach to network analysis within transport research, this paper considers the issue of determining accessibility between railway stations (on the route between Weymouth and London Waterloo) served by a mixture of high-speed and stopping services.A rail network is physically defined by the locations of tracks, but travel times are also dependent on whether stations are visited by high-speed services as well as stopping services. A single rail route therefore has to be represented not as a (topologically) straight line, but as a more traditional graph with high connectivity between nodes. Reformulating this into a matrix-based definition allows the Floyd-Warshall algorithm to efficiently determine the optimal routing (and hence travel times) between<br/
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