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This paper examines the factors affecting police officer willingness to adhere to a code of silence among the police in Croatia and Serbia. The paper explores the factors predicting police codes of silence in two countries formed after the dissolution of the former Yugoslavia in the early 1990s that pursued separate development paths. A police integrity questionnaire recorded the views of 1,007 police officers in Croatia and 1,843 police officers in Serbia. Multivariate modelling was used to analyse the predictors of officers' perceptions of whether they would report the violation in different scenarios. Decades since the break-up of the former Yugoslavia, the results indicate that many of the factors predicting the code of silence remain similar across police officers in the two countries. [ABSTRACT FROM AUTHOR]

Human strategies for solving the travelling salesperson problem (TSP) continue to draw the attention of the researcher community, both to further understanding of human decision-making and inspiration for the design of automated solvers. Online games represent an efficient way of collecting large amounts of human solutions to the TSP, and PathGame is a game focusing on non-Euclideanclosed-form TSP. To capture the instinctive decision-making process of the users, PathGame requires users to solve the problem as quickly as possible, while still favouring more efficient tours. In the initial study presented here, we have used PathGame to collect a dataset of over 16,000 tours, containing over 22,000,000 destinations. Our analysis of the data revealed new insights related to ways in which humans solve TSP and the time it takes them when forced to solve TSPs of large complexity quickly. [ABSTRACT FROM AUTHOR]

In this paper, we propose new method for automated cryptanalysis of substitution cryptosystem using Hill climbing algorithm. New heuristic function is proposed in order to drastically improve overall fitness of the standard Hill climbing algorithm. Several fitness functions have been tested and we try to detremine which of them perform better in specific situations using our suggested time-dependent measure goodness. We conclude which of those functions should be used in case we are dealing with short or long texts. [ABSTRACT FROM AUTHOR]

An attribute-based encryption scheme capable of handling multiple authorities was recently proposed by Chase. The scheme is built upon a single-authority attribute-based encryption scheme presented earlier by Sahai and Waters. Chase's construction uses a trusted central authority that is inherently capable of decrypting arbitrary ciphertexts created within the system. We present a multi-authority attribute-based encryption scheme in which only the set of recipients defined by the encrypting party can decrypt a corresponding ciphertext. The central authority is viewed as ‘honest-but-curious’: on the one hand, it honestly follows the protocol, and on the other hand, it is curious to decrypt arbitrary ciphertexts thus violating the intent of the encrypting party. The proposed scheme, which like its predecessors relies on the Bilinear Diffie–Hellman assumption, has a complexity comparable to that of Chase's scheme. We prove that our scheme is secure in the selective ID model and can tolerate an honest-but-curious central authority. [ABSTRACT FROM PUBLISHER]

We say that a collection of subsets α = [B1,..., Bk] of a group G is a factorization if G = B1,...,Bk and each element of G is expressed in a unique way in this product. By using a special type of mappings between groups A and B, called free mappings, we exhibit an algorithmic way to construct nontrivial factorizations of a group G, such that G ≅ A × B. In Lemma 3.2 we give a simple way to construct free mappings. It turns out that this approach has greater importance when G is an abelian group. We give illustrative examples of this method in the cases ℤp × ℤp and ℤp × ℤq where p and q are different prime numbers. An interesting connection between free mappings and Rédei's theorem, with a number theoretic implication, is given. [ABSTRACT FROM AUTHOR]