13,619 research outputs found
Mitsch's order and inclusion for binary relations and partitions
Mitsch's natural partial order on the semigroup of binary relations is here
characterised by equations in the theory of relation algebras. The natural
partial order has a complex relationship with the compatible partial order of
inclusion, which is explored by means of a sublattice of the lattice of
preorders on the semigroup. The corresponding sublattice for the partition
monoid is also described.Comment: 8 pages, 2 figure
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Do social networking groups support online petitions?
This article is the post-print version of the final paper that has been accepted for publication and is forthcoming in Transforming Government: People, Process and Policy. Copyright @ Emerald Group Publishing LimitedEPetitioning has been emerging as arguably the most important eParticipation institutional activity. This paper aims to provide some insights into how ePetitions are perceived and supported by social networking sites. The connection between the UK government’s ePetitioning system and social networking groups linking to governmental petitions was investigated. Online data from Facebook were collected and analysed with respect to numbers of supporters compared to official signatures. The results indicate that although the process of signing an official petition is not more complex than joining a Facebook group, the membership of respective Facebook groups can be much higher. In particular, certain topics experienced very high support on Facebook which did not convert to signatures. The paper raises interesting questions about the potential uptake of citizen-government interactions in policy making mechanisms.The online research tool used for data collection in this paper was developed by Steven Sams who acknowledges support by the World Class University (WCU) program through the National Research Foundation of Korea. The program is funded by the Korean Ministry of Education, Science and Technology (No. 515-82-06574
A Programmable Liquid Collimator for Both Coded Aperture Adaptive Imaging and Multiplexed Compton Scatter Tomography
A novel, fully reconfigurable collimator device for gamma-ray and X-ray imaging was built and tested as a coded aperture. The device consisted of 10x10, 5x5x5 mm3 chambers. Each chamber either was filled with an attenuating liquid, stopping photons, or evacuated of the attenuating liquid, allowing the photons to pass through. As the pattern of on and off chambers was manipulated, different, semi-independent views of the gamma-ray source were found. Noise in reconstructed images decreased in all tests. Image reconstruction was performed with correlation methods and Maximum Likelihood Expectation Maximization (ML-EM). Using 10 mask patterns, the signal-to-noise ratio (SNR) in images of a Co-57 point source increased by a factor of 4.3 using correlation methods and by a factor of at least 50 using ML-EM. SNR in images of a Cd-109 source with high background increased by a factor of 3.0 using correlation methods and by a factor of 1.8 using ML-EM. Two extended sources were imaged, and the images improved when more masks were used. The Multiplexed Compton Scatter Tomography (MCST) forward problem using a PHDs Co high purity germanium (HPGe) detector was tested and evaluated. Potential applications are discussed in detail
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