Atomistic subsemirings of the lattice of subspaces of an algebra

Let A be an associative algebra with identity over a field k. An atomistic subsemiring R of the lattice of subspaces of A, endowed with the natural product, is a subsemiring which is a closed atomistic sublattice. When R has no zero divisors, the set of atoms of R is endowed with a multivalued product. We introduce an equivalence relation on the set of atoms such that the quotient set with the induced product is a monoid, called the condensation monoid. Under suitable hypotheses on R, we show that this monoid is a group and the class of k1_A is the set of atoms of a subalgebra of A called the focal subalgebra. This construction can be iterated to obtain higher condensation groups and focal subalgebras. We apply these results to G-algebras for G a group; in particular, we use them to define new invariants for finite-dimensional irreducible projective representations.Comment: 14 page

Editors' Introduction

Hermeneutics has a long tradition in the history of philosophy. It carries the task of Hermes to bring God’s message to humans and translate it without betraying it. This special issue of the journal Critical Hermeneutics proposes a double research track: veritative hermeneutics and hermeneutic realism. This double track testifies to the original purpose of hermeneutics to formulate fundamental philosophical questions in light of human historical experience. Opposed to relativism, veritative hermeneutics and hermeneutic realism focus on truth, objectivity, the structure of reality, normativity, and meaning. The issue publishes contributions of this track’s pioneers (Gaspare Mura – veritative hermeneutics, Günter Figal, and Anton Friedrich Koch – hermeneutic realism) as well as authors that explore this track from various perspectives: ethics, personalism, normativity, testimony, Biblical hermeneutics and Jewish thought, religious language, meaning. In this introduction, we will first present the authors working on veritative hermeneutics, then those working on hermeneutic realism...

PRIVACY PRESERVATION IN LOCATION-BASED PROXIMITY SERVICES

One of the most common location-based services (LBS) in the geo-aware social network market is the notification of friends geographically in proximity. In addition to the privacy threats related to the use of traditional LBS, there are other privacy threats specific to proximity services. Existing privacy-preserving solutions for LBS are not effective or directly applicable. For this reason, we developed techniques that specifically address the privacy threats of this type of services. The proposed techniques let a user control what is disclosed about her location and formally guarantee that these requirements are satisfied. An extensive empirical evaluation was performed, by using a dataset of user movement generated using an agent-based simulator, in which agents reflect the behavior of typical users of proximity services. The techniques were also integrated in a fully functional privacy-aware proximity service, for which we developed desktop and mobile clients

A Hybrid optimization method for real-time pump scheduling

Session S6-02, Special Session: Evolutionary Computing in Water Resources Planning and Management IILinear, non-linear and dynamic programming, heuristics and evolutionary computation are amongst the techniques which have been applied to obtain solutions to optimal pump-scheduling problems. Most of these either greatly simplify the complex water distribution system or require significant time to solve the problem. The scheduling of pumps is frequently undertaken in near-real time, in order to minimize cost and maximize energy savings. However, this requires a computationally efficient algorithm that can rapidly identify an acceptable solution. In this paper, a hybrid optimization model is presented, coupling Linear Programming and Genetic Algorithms. The resulting hybrid optimization model has demonstrated more rapid convergence with respect to the traditional metaheuristic algorithms, whilst maintaining a good level of reliability

1-hypergroups of small sizes

In this paper, we show a new construction of hypergroups that, under appropriate conditions, are complete hypergroups or non-complete 1-hypergroups. Furthermore, we classify the 1-hypergroups of size 5 and 6 based on the partition induced by the fundamental relation \u3b2. Many of these hypergroups can be obtained using the aforesaid hypergroup construction

Location-related privacy in geo-social networks

Geo-social networks (GeoSNs) provide context-aware services that help associate location with users and content. The proliferation of GeoSNs indicates that they're rapidly attracting users. GeoSNs currently offer different types of services, including photo sharing, friend tracking, and "check-ins. " However, this ability to reveal users' locations causes new privacy threats, which in turn call for new privacy-protection methods. The authors study four privacy aspects central to these social networks - location, absence, co-location, and identity privacy - and describe possible means of protecting privacy in these circumstances

Privacy in geo-social networks: proximity notification with untrusted service providers and curious buddies

A major feature of the emerging geo-social networks is the ability to notify a user when any of his friends (also called buddies) happens to be geographically in proximity. This proximity service is usually offered by the network itself or by a third party service provider (SP) using location data acquired from the users. This paper provides a rigorous theoretical and experimental analysis of the existing solutions for the location privacy problem in proximity services. This is a serious problem for users who do not trust the SP to handle their location data and would only like to release their location information in a generalized form to participating buddies. The paper presents two new protocols providing complete privacy with respect to the SP and controllable privacy with respect to the buddies. The analytical and experimental analysis of the protocols takes into account privacy, service precision, and computation and communication costs, showing the superiority of the new protocols compared to those appeared in the literature to date. The proposed protocols have also been tested in a full system implementation of the proximity service