Efficient Bit-Decomposition and Modulus-Conversion Protocols with an Honest Majority

We propose secret-sharing-based bit-decomposition and modulus conversion protocols for a prime order ring $\mathbb{Z}_p$ with an honest majority: an adversary can corrupt $k-1$ parties of $n$ parties and $2k-1 \le n$. Our protocols are secure against passive and active adversaries depending on the components of our protocols. We assume a secret is an $\ell$-bit element and $2^{\ell+\lceil \log m \rceil} < p$, where $m= k$ in the passive security and $m= \binom{n}{k-1}$ in the active security. The outputs of our bit-decomposition and modulus-conversion protocols are $\ell$ tuple of shares in $\mathbb{Z}_2$ and a share in $\mathbb{Z}_{p\u27}$, respectively, where $p\u27$ is the modulus to be converted. If $k$ and $n$ are small, the communication complexity of our passively secure bit-decomposition and modulus-conversion protocols are $O(\ell)$ bits and $O(\lceil \log p\u27 \rceil)$ bits, respectively. Our key observation is that a quotient of additive shares can be computed from the \emph{least} significant $\lceil \log m \rceil$ bits. If a secret $a$ is ``shifted\u27\u27 and additively shared by $x_i$ in $\mathbb{Z}_p$ as $2^{\lceil \log m \rceil}a = \sum_{i=0}^{m-1} x_i = 2^{ \lceil \log m \rceil} a + qp$, the least significant $\lceil \log m \rceil$ bits of $\sum_{i=0}^{m-1} x_i$ determines $q$ since $p$ is an odd prime and the least significant $\lceil \log m \rceil$ bits of $2^{\lceil \log m \rceil} a$ are $0$s

Results from the intercalibration of optical low light calibration sources 2011

Following the 38th Annual European Meeting on Atmospheric Studies by Optical Methods in Siuntio in Finland, an intercalibration workshop for optical low light calibration sources was held in Sodankylä, Finland. The main purpose of this workshop was to provide a comparable scale for absolute measurements of aurora and airglow. All sources brought to the intercalibration workshop were compared to the Fritz Peak reference source using the Lindau Calibration Photometer built by Wilhelm Barke and Hans Lauche in 1984. The results were compared to several earlier intercalibration workshops. It was found that most sources were fairly stable over time, with errors in the range of 5–25%. To further validate the results, two sources were also intercalibrated at UNIS, Longyearbyen, Svalbard. Preliminary analysis indicates agreement with the intercalibration in Sodankylä within about 15–25%

The Acceleration and Storage of Radioactive Ions for a Beta-Beam Facility

The term beta-beam has been coined for the production of a pure beam of electron neutrinos or their antiparticles through the decay of radioactive ions circulating in a storage ring. This concept requires radioactive ions to be accelerated to as high Lorentz gamma as 150. The neutrino source itself consists of a storage ring for this energy range, with long straight sections in line with the experiment(s). Such a decay ring does not exist at CERN today, nor does a high-intensity proton source for the production of the radioactive ions. Nevertheless, the existing CERN accelerator infrastructure could be used as this would still represent an important saving for a beta-beam facility.Comment: beta-beam working group website at http://cern.ch/beta-bea

Nuclear waste related satellite mapping in northwest Russia

In the early phase of a project organized by the Norwegian Radiation Protection Authority (NRPA) dealing with monitoring of radioactive radiation from nuclear waste deposited at the former naval station Andreeva Bay in northwest Russia, a suitable base map at a scale sufficiently large to be used as a georeferencing tool for radiation measurements and also as a background map for presentations, was not available. It was therefore decided to use high resolution satellite imagery for this purpose, and a collaboration with the Geomatics section - IMT at the Norwegian University of Life Sciences (UMB), was established.A Landsat-7 ETM+ precision corrected scene from the USGS 15 meter resolution data collection was used as a basis for a georeference adjustment of a system corrected QuickBird sub-scene. By establishing an adequate transformations based on Ground Control Points (GCPs), between the adjusted QuickBird sub-scene and a local grid, it was possible to locate the original radioactive radiation measurements with acceptable precision within the UTM Sone 36 N WGS84 geographical reference frame.At a later stage of the project, after the Satellite Image Map preparation, a digital version in raster format of a Russian topographic map sheet at scale 1:50 000 became available. This dataset offered a possibility for the assessment of the combined Landsat-7 ETM+/QuickBird rectification, and in addition an opportunity for an assessment of the influence of the terrain elevation on the geometry of the rectified satellite image

Nuclear waste related satellite mapping in northwest Russia

In the early phase of a project organized by the Norwegian Radiation Protection Authority (NRPA) dealing with monitoring of radioactive radiation from nuclear waste deposited at the former naval station Andreeva Bay in northwest Russia, a suitable base map at a scale sufficiently large to be used as a georeferencing tool for radiation measurements and also as a background map for presentations, was not available. It was therefore decided to use high resolution satellite imagery for this purpose, and a collaboration with the Geomatics section - IMT at the Norwegian University of Life Sciences (UMB), was established.A Landsat-7 ETM+ precision corrected scene from the USGS 15 meter resolution data collection was used as a basis for a georeference adjustment of a system corrected QuickBird sub-scene. By establishing an adequate transformations based on Ground Control Points (GCPs), between the adjusted QuickBird sub-scene and a local grid, it was possible to locate the original radioactive radiation measurements with acceptable precision within the UTM Sone 36 N WGS84 geographical reference frame.At a later stage of the project, after the Satellite Image Map preparation, a digital version in raster format of a Russian topographic map sheet at scale 1:50 000 became available. This dataset offered a possibility for the assessment of the combined Landsat-7 ETM+/QuickBird rectification, and in addition an opportunity for an assessment of the influence of the terrain elevation on the geometry of the rectified satellite image