A third order analytic approximation solution of Lyapunov orbits around the collinear equilibrium in the planar restricted three-body problem by utilizing the Lindstedt Poincaré method is presented. The primaries are oblate bodies and sources of radiation pressure. The theory has been applied to the binary α-Centuari system in six cases. Also, we have determined numerically the positions of the collinear equilibrium points and shown the effects of the parameters concerned with these equilibrium points.
In this paper, a class of -rings which is a generalization of*–reversible rings is introduced. A ring with involution * is called central *–reversible if for a,b ∈ R whenever ab= 0, b* a is central in R. Since every *–reversible ring is central *–reversible, sufficient conditions for central *–reversible rings to be*–reversible is studied. We show that some results of *–reversible rings can be extended to central *–reversible ring. For an Armendariz ring , we prove that is central *–reversible if and only if the polynomial ringR[X] is central *–reversible if and only if the Laurent polynomial ringR[x, x-1] is central *–reversible.
Aims: To design and implement a classification-based model using specific features for identification and extraction of high quality questions in a thread.
Study Design: The study design is divided into three modules: preprocessing, configuration, and question classification
Place and Duration of Study: Department of Computer Science of the Federal University of Technology Akure, between June 2016 and December 2016
Methodology: This research proposes a way of identifying, extracting and classifying questions in order to enhance high quality answers in an online forum. One of the major issues in question extraction and classification in forum is the restriction on the number of categories considered such as Who, What, Where, Where, Which, Why and How which are not sufficient to capture all possible questions. In this work, a number of parameters were proposed and aggregated using fuzzy logic for context based spam detection and removal in order to enhance question identification and classification. Part of speech (POS) tagging was applied to analyse the structure of each extracted sentence based on the presence and position of predefined question tags; with this, issues like case sensitivity, grammatical construction and synonyms are addressed. Question classification is carried out with Naïve Bayes and identifying semantic relationship between extracted questions is achieved with cosine similarity model. Experiments were performed on dataset constructed from Research Gate website.
Results: We presented questions extracted from researchgate website into the system. The output consists of the corresponding POS tags and the category the question is classified into. The number of questions extracted from the website is dependent on the number of questions available in a forum. We were able to achieve a successful result of 3015 correctly extracted and classified questions at 80% POS tag occurrence.
Conclusion: Our approach to question identification and classification was effective and covers more question categories. This can be applied to any question answering system.
Replay attack is considered a common attacking technique that is used by adversaries to gain access to confidential information. Several approaches have been proposed to prevent replay attack in security-critical systems such as Automated Teller Machines (ATM) systems. Among those approaches is a recent one called the Mutual Chain Authentication Protocol for the Saudi Payments Network transactions (MCAP). This protocol aims to allow Saudi banking systems to overcome existing weaknesses in the currently used Two-Factor Authentication (2FA) protocols. In this paper, we analyze and verify the recent MCAP authentication protocol against replay attacks. Therefore, we examine the mutual authentication between the ATM Terminal, Sponsoring Banks (SBAT), Saudi Payments Network (SPAN) and the Issuing of Financial Bank (CIFI). The paper also provides a formal analysis of the MCAP to conduct formal proofs of the MCAP protocols against replay attacks.