Search results for " Complexity"
showing 10 items of 623 documents
Panel — Assessing Critical Social Theory Research in Information Systems
1997
The Critical Social Theory (CST) program of information systems research is now just over a decade old. Although the number of researchers associated with the CST program are few, they have had a disproportionately larger impact on the field than other research communities. The main reason for this disproportionate impact can be found in the intense and incisive radical critiques of the foundational assumptions of our field that CST researchers have conducted. These radical critiques have helped to open up the theoretical debate on IS research and point out new directions for future inquiry. But as we turn the century, new challenges are emerging. New information technologies (IT) are rapid…
Rotation-Invariant Texture Retrieval via Signature Alignment Based on Steerable Sub-Gaussian Modeling
2008
This paper addresses the construction of a novel efficient rotation-invariant texture retrieval method that is based on the alignment in angle of signatures obtained via a steerable sub-Gaussian model. In our proposed scheme, we first construct a steerable multivariate sub-Gaussian model, where the fractional lower-order moments of a given image are associated with those of its rotated versions. The feature extraction step consists of estimating the so-called covariations between the orientation subbands of the corresponding steerable pyramid at the same or at adjacent decomposition levels and building an appropriate signature that can be rotated directly without the need of rotating the im…
Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
2016
Algorithmic complexity vulnerabilities are an opportunity for an ad-versary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully con-ducted attack which takes advantage of the worst case computational complexi-ty of O(n2) of a hash table data structure used to store active sessions. The …
Partitionability, coverability and colorability in graphs
2014
Our research are about graph coloring with distance constraints (packing coloring) or neighborhood constraints (Grundy coloring). Let S={si| i in N*} be a non decreasing sequence of integers. An S-packing coloring is a proper coloring such that every set of color i is an si-packing (a set of vertices at pairwise distance greater than si). A graph G is (s1,... ,sk)-colorable if there exists a packing coloring of G with colors 1,... ,k. A Grundy coloring is a proper vertex coloring such that for every vertex of color i, u is adjacent to a vertex of color j, for each ji. These results allow us to determine S-packing coloring of these lattices for several sequences of integers. We examine a cla…
The Effects of Database Complexity on SQL Query Formulation
2020
In Structured Query Language (SQL) education, students often execute queries against a simple exercise database. Recently, databases that are more realistic have been utilized to the effect that students find exercises more interesting and useful, as these databases more accurately mimic databases students are likely to encounter in their future work environments. However, using even the most engaging database can be counterproductive to learning, if a student is not able to formulate correct queries due to the complexity of the database schema. Scientific evidence on the effects of database complexity on student’s query formulation is limited, and with queries from 744 students against thr…
A Learning Automata Based Solution to Service Selection in Stochastic Environments
2010
Published version of a paper published in the book: Trends in Applied Intelligent Systems. Also available on SpringerLink: http://dx.doi.org/10.1007/978-3-642-13033-5_22 With the abundance of services available in today’s world, identifying those of high quality is becoming increasingly difficult. Reputation systems can offer generic recommendations by aggregating user provided opinions about service quality, however, are prone to ballot stuffing and badmouthing . In general, unfair ratings may degrade the trustworthiness of reputation systems, and changes in service quality over time render previous ratings unreliable. In this paper, we provide a novel solution to the above problems based …
An Anonymous Delegatable Attribute-based Credential Scheme for a Collaborative E-health Environment
2019
We propose an efficient anonymous, attribute-based credential scheme capable of provisioning multi-level credential delegations. It is integrated with a mechanism to revoke the anonymity of credentials for resolving access disputes and making users accountable for their actions. The proposed scheme has a lower end-user computational complexity in comparison to existing credential schemes with delegatability and has a comparable level of performance with the credential standards of U-Prove and Idemix. Furthermore, we demonstrate how the proposed scheme can be applied to a collaborative e-health environment to provide its users with the necessary anonymous access with delegation capabilities.
Upper bound on the communication complexity of private information retrieval
1997
We construct a scheme for private information retrieval with k databases and communication complexity O(n 1/(2k−1) ).
A Neural Network model for the Evaluation of Text Complexity in Italian Language: a Representation Point of View
2018
Abstract The goal of a text simplification system (TS) is to create a new text suited to the characteristics of a reader, with the final goal of making it more understandable.The building of an Automatic Text Simplification System (ATS) cannot be separated from a correct evaluation of the text complexity. In fact the ATS must be capable of understanding if a text should be simplified for the target reader or not. In a previous work we have presented a model capable of classifying Italian sentences based on their complexity level. Our model is a Long Short Term Memory (LSTM) Neural Network capable of learning the features of easy-to-read and complex-to-read sentences autonomously from a anno…