Self-stabilizing protocol for anonymous oriented bi-directional rings under unfair distributed schedulers with a leader

We propose a self-stabilizing protocol for anonymous oriented bi-directional rings of any size under unfair distributed schedulers with a leader. The protocol is a randomized self-stabilizing, meaning that starting from an arbitrary configuration it converges (with probability 1) in finite time to a legitimate configuration (i.e. global system state) without the need for explicit exception handler of backward recovery. A fault may throw the system into an illegitimate configuration, but the system will autonomously resume a legitimate configuration, by regarding the current illegitimate configuration as an initial configuration, if the fault is transient. A self-stabilizing system thus tolerates any kind and any finite number of transient faults. The protocol can be used to implement an unfair distributed mutual exclusion in any ring topology network; Keywords: self-stabilizing protocol, anonymous oriented bi-directional ring, unfair distributed schedulers. Ring topology network, non-uniform and anonymous network, self-stabilization, fault tolerance, legitimate configuration

Peer-to-Peer Secure Multi-Party Numerical Computation Facing Malicious Adversaries

We propose an efficient framework for enabling secure multi-party numerical computations in a Peer-to-Peer network. This problem arises in a range of applications such as collaborative filtering, distributed computation of trust and reputation, monitoring and other tasks, where the computing nodes is expected to preserve the privacy of their inputs while performing a joint computation of a certain function. Although there is a rich literature in the field of distributed systems security concerning secure multi-party computation, in practice it is hard to deploy those methods in very large scale Peer-to-Peer networks. In this work, we try to bridge the gap between theoretical algorithms in the security domain, and a practical Peer-to-Peer deployment. We consider two security models. The first is the semi-honest model where peers correctly follow the protocol, but try to reveal private information. We provide three possible schemes for secure multi-party numerical computation for this model and identify a single light-weight scheme which outperforms the others. Using extensive simulation results over real Internet topologies, we demonstrate that our scheme is scalable to very large networks, with up to millions of nodes. The second model we consider is the malicious peers model, where peers can behave arbitrarily, deliberately trying to affect the results of the computation as well as compromising the privacy of other peers. For this model we provide a fourth scheme to defend the execution of the computation against the malicious peers. The proposed scheme has a higher complexity relative to the semi-honest model. Overall, we provide the Peer-to-Peer network designer a set of tools to choose from, based on the desired level of security.Comment: Submitted to Peer-to-Peer Networking and Applications Journal (PPNA) 200

PROCAIN: protein profile comparison with assisting information

Detection of remote sequence homology is essential for the accurate inference of protein structure, function and evolution. The most sensitive detection methods involve the comparison of evolutionary patterns reflected in multiple sequence alignments (MSAs) of protein families. We present PROCAIN, a new method for MSA comparison based on the combination of ‘vertical’ MSA context (substitution constraints at individual sequence positions) and ‘horizontal’ context (patterns of residue content at multiple positions). Based on a simple and tractable profile methodology and primitive measures for the similarity of horizontal MSA patterns, the method achieves the quality of homology detection comparable to a more complex advanced method employing hidden Markov models (HMMs) and secondary structure (SS) prediction. Adding SS information further improves PROCAIN performance beyond the capabilities of current state-of-the-art tools. The potential value of the method for structure/function predictions is illustrated by the detection of subtle homology between evolutionary distant yet structurally similar protein domains. ProCAIn, relevant databases and tools can be downloaded from: http://prodata.swmed.edu/procain/download. The web server can be accessed at http://prodata.swmed.edu/procain/procain.php

Characterization of three-phase flow and WAG injection in oil reservoirs

Large quantities of oil usually remain in oil reservoirs after conventional water floods. A significant part of this remaining oil can still be economically recovered by Water- Alternating-Gas (WAG) injection. WAG injection involves drainage and imbibition processes taking place sequentially, hence the numerical simulation of the WAG process requires reliable knowledge of three-phase relative permeability (kr) accounting for cyclic hysteresis effects. In this study, the results of a series of unsteady-state two-phase displacements and WAG coreflood experiments were employed to investigate the behaviour of three-phase kr and hysteresis effects in the WAG process. The experiments were carried out on two different cores with different characteristics and wettability conditions, using a low IFT (interfacial tension) gas–oil system. The first part of this study, evaluates the current approach used in the oil industry for simulation of the WAG process, in which the two-phase relative permeability data are employed to generate three-phase kr values using correlations (e.g. Stone, Baker). The performance of each of the existing three-phase relative permeability models was assessed against the experimental data. The results showed that choosing inappropriate three-phase kr model in simulation of the WAG experiments can lead to large errors in prediction of fluid production and differential pressure. While some models perform better than others, all of the three-phase kr models examined in this study failed to adequately predict the fluid production behaviour observed in the experiments. The continued production of oil after the breakthrough of the gas, which was one of the features of gas and WAG injection experiments at low gas-oil IFT, was not captured with these models. The second aim of this research was to develop a method for obtaining the values of three-phase relative permeabilities directly from WAG core flood experiments. For this purpose, a new history matching method was devised based on a Genetic Algorithm to estimate three-phase kr from unsteady-state coreflood experiments. Based on this methodology, a three-phase coreflood optimizer was developed that generates best kr values by matching the experimentally obtained production and pressure data. First, the iii integrity of the developed software was successfully verified by using two sets of experimental three-phase kr data published in the literature. Then, the program was used to determine three-phase relative permeability of various cycles of the WAG experiments performed at different wettability conditions. Two key parameters affecting the WAG performance, including the hysteresis phenomena occurring between kr of the different WAG cycles and the impact of wettability of the rock, have been investigated. The data have been used to evaluate the existing hysteresis models published in the literature. Some of the shortcomings associated with the existing methods have been revealed and discussed. In the latter part of the thesis, a new methodology is proposed for modelling of threephase relative permeability for WAG injection. This approach addresses the hysteresis effects in the three-phase kr taking place during the WAG process and attempts to reduce the inadequacies observed in the existing models. The integrity of this technique has been validated against the three-phase kr data obtained from our WAG experiments

The BG News September 28, 2006

The BGSU campus student newspaper September 28, 2006. Volume 97 - Issue 29https://scholarworks.bgsu.edu/bg-news/8646/thumbnail.jp

Fast self-stabilizing byzantine tolerant digital clock synchronization

Consider a distributed network in which up to a third of the nodes may be Byzantine, and in which the non-faulty nodes may be subject to transient faults that alter their memory in an arbitrary fashion. Within the context of this model, we are interested in the digital clock synchronization problem; which consists of agreeing on bounded integer counters, and increasing these counters regularly. It has been postulated in the past that synchronization cannot be solved in a Byzantine tolerant and self-stabilizing manner. The first solution to this problem had an expected exponential convergence time. Later, a deterministic solution was published with linear convergence time, which is optimal for deterministic solutions. In the current paper we achieve an expected constant convergence time. We thus obtain the optimal probabilistic solution, both in terms of convergence time and in terms of resilience to Byzantine adversaries

University of South Alabama College of Medicine Annual Report for 2015-2016

This Annual Report of the College of Medicine catalogues recent accomplishments of our faculty, students, residents, fellows and staff in teaching, research, patient care, scholarly and community service activities during the 2015-16 academic year.https://jagworks.southalabama.edu/com_report/1000/thumbnail.jp

The Ouachita Circle Summer 2005

Tsunami Relief: Professors participate in relief effort Spring Commencement: 196 students receive degrees Music, Mud & Mayhem: Arkansas\u27 Most Exciting College Weekend Schleiffs minister to MKs: Former missionaries provide MKS home Point of Grace aids students: Group provides scholarship Fitz Hill leads Opportunity Fund: Alumnus returns to raise scholarship funds President becomes author: Westmoreland shares ideas on Christian leadership Circle of Excellence Campaign: $62.5 million goal surpassedhttps://scholarlycommons.obu.edu/alumni_mag/1055/thumbnail.jp

Progress on Nutrient Composition, Meat Standardization and Grading, Processing and Safety in Different Types of Meat Sources

The alleged responsibility of meats and processed meat products for some of our population’s major health issues has created an opportunity for the promotion of meat analogs. This emerging competition forces the need for changes in livestock production systems for improving nutritive value and obtaining healthier and safer meat products. The morbidity and mortality attributed to Salmonella and other pathogens remain a public health issue. Hence, there is an urgent need for developing intervention technologies to control such pathogens. Beef is packaged with an array of healthy nutrients and is the highest valued livestock product. However, staples (e.g., pork, poultry) and some co-products can also be nutrient dense and/or provide a unique sensory experience with advantageous technological quality. Carcass yield is a major determinant of livestock value. Hence, objective technologies are strongly needed to effectively segregate the heterogeneous supply of carcasses into homogeneous groups in yield of cuts. Not all meats are created equal, and differences in their intrinsic characteristics may be expected when they are produced in different regions and under diverse production schemes. Nevertheless, reports aiming to characterize meats originated from different zones (e.g., tropical latitudes) are scarce. This Special Issue of Foods, “Progress on Nutrient Composition, Meat Standardization, Grading, Processing, and Safety for Different Types of Meat Sources”, comprising fourteen peer-reviewed papers, is now being released as a book that will serve as an invaluable reference in addressing the current dearth of knowledge regarding the aforementioned topics, and is also envisaged to serve in updating food scientists and stakeholders of the meat value chain globally