Copy Of Frame Research Articles

A Novel Optical High-Availability Seamless Redundancy (OHSR) Design Based on Beam Splitting / Combining Techniques

The standard high-availability seamless redundancy (HSR) protocol utilizes duplicated frame copies of each sent frame for zero fail over time. This means that even in cases of a node or link failure, the destination node will receive at least one copy of the sent frame, resulting in no network downtime. However, the standard HSR is mostly based on the electrical signal connection inside the node, which leads to the production of considerable latency at each node due to frame processing. Therefore, in a large scale HSR ring network, the accumulated latencies become significant and can often restrict the mission-critical real-time application of HSR. In this paper, we present a novel design for optical HSR (OHSR) that uses beam splitting/combining techniques. The proposed OHSR passes the frames directly to adjacent nodes without frame processing at each node, thereby theoretically generating no latency in any node. Various simulations for network samples, made to validate the OHSR design and its performance, show that the OHSR outperforms the standard HSR.

DVP: A Novel High-Availability Seamless Redundancy (HSR) Protocol Traffic-Reduction Algorithm for a Substation Automation System Network

The high-availability seamless redundancy (HSR) protocol, a potential candidate for substation automation system (SAS) networks, provides duplicated frame copies of each sent frame, with zero fault-recovery time. This means that even in the case of node or link failure, the destination node will receive at least one copy of the sent frame. Consequently, there is no network operation down time. However, the forwarding process of the QuadBox node in HSR is not smart and relies solely on duplication and random forwarding of all received frames. Thus, if a unicast frame is sent in any closed-loop network, the frame copies will be spread through most of all the links in both directions until they reach the destination node, which inevitably results in significant, unnecessary network traffic. In this paper, we present an algorithm called the dual virtual paths (DVP) algorithm to solve such an HSR excessive traffic issue. The idea behind our DVP algorithm is to establish automatic DVP between each HSR node and all the other nodes in the network, except for the QuadBox node. These virtual paths will be used for DVP unicast traffic transmission, rather than using the standard HSR transmission process. Therefore, the DVP algorithm results in less traffic, because there is no duplication or random forwarding, contrary to standard HSR. For the sample networks selected in this paper, the DVP algorithm shows more than a 70% reduction in network traffic and about an 80% reduction in the discarded traffic compared to the standard HSR protocol.

Improvement of high-availability seamless redundancy (HSR) traffic performance for smart grid communications

High-availability seamless redundancy (HSR) is a redundancy protocol for Ethernet networks that provides two frame copies for each frame sent. Each copy will pass through separate physical paths, pursuing zero fault recovery time. This means that even in the case of a node or a link failure, there is no stoppage of network operations whatsoever. HSR is a potential candidate for the communications of a smart grid, but its main drawback is the unnecessary traffic created due to the duplicated copies of each sent frame, which are generated and circulated inside the network. This downside will degrade network performance and might cause network congestion or even stoppage. In this paper, wepresent two approaches to solve the above-mentioned problem. The first approach is called quick removing (QR), and is suited to ring or connected ring topologies. The idea is to remove the duplicated frame copies from the network when all the nodes have received one copy of the sent frame and begin to receive the second copy. Therefore, the forwarding of those frame copies until they reach the source node, as occurs in standard HSR, is not needed in QR. Our example shows a traffic reduction of 37.5% compared to the standard HSR protocol. The second approach is called the virtual ring (VRing), which divides any closed-loop HSR network into several VRings. Each VRing will circulate the traffic of a corresponding group of nodes within it. Therefore, the traffic in that group will not affect any of the other network links or nodes, which results in an enhancement of traffic performance. For our sample network, the VRing approach shows a network traffic reduction in the range of 67.7 to 48.4% in a healthy network case and 89.7 to 44.8% in a faulty network case, compared to standard HSR.

DMT Optimal Cooperative Protocols with Destination-Based Selection of the Best Relay

We design a cooperative protocol in the context of wireless mesh networks in order to increase the reliability of wireless links. Destination terminals ask for cooperation when they fail in decoding data frames transmitted by source terminals. In that case, each destination terminal D calls a specific relay terminal B with a signaling frame to help its transmission with source terminal S. To select appropriate relays, destination terminals maintain tables of relay terminals, one for each possible source address. These tables are constituted by passively overhearing ongoing transmissions. Hence, when cooperation is needed between S and D, and when a relay B is found by terminal D in the relay table associated with terminal S, the destination terminal sends a negative acknowledgment frame that contains the address of B. When the best relay B has successfully decoded the source message, it sends a copy of the data frame to D using a selective decode-and-forward transmission scheme. The on-demand approach allows maximization of the spatial multiplexing gain and the cooperation of the best relay allows maximization of the spatial diversity order. Hence, the proposed protocol achieves optimal diversity-multiplexing trade-off performance. Moreover, this performance is achieved through a collision-free selection process.

A membrane protein with similarity to N-methylphenylalanine pilins is essential for DNA binding by competent Bacillus subtilis

In a cloned copy of comG open reading frame 3 (ORF3), an in-frame deletion was generated by site-directed in vitro mutagenesis, removing the coding sequence for 15 amino acids from the central portion of this pilin-related protein. The mutagenized ORF3 was incorporated into the Bacillus subtilis chromosome, replacing the wild-type ORF3. The presence of the deleted ORF3 in the chromosome, as confirmed by Southern analysis, was associated with the complete loss of competence by the mutant strain. The ability of the mutant cells to bind exogenous radiolabeled DNA was reduced to the level of nonspecific binding of DNA by noncompetent cells. The chromosomal ORF3 mutation was partially complemented in trans by a plasmid-encoded wild-type ORF3 copy under PSPAC control upon induction of the PSPAC promoter. Using antiserum raised against a synthetic 14-mer oligopeptide deduced from the ORF3 sequence, an immunoreactive band of approximately the expected molecular size was obtained in Western blot (immunoblot) experiments with extracts of cells containing the plasmid-encoded inducible gene. A signal was also detected when cells harboring the chromosomal wild-type or mutant ORF3 in single copy were grown in competence medium. This signal was detected only in the light-buoyant-density (competent) cell fraction and only after the transition from the exponential to the stationary growth phase. In cell fractionation experiments with competent cell extracts, the immunoreactive protein was found in both the NaOH-insoluble and -soluble membrane fractions and was sensitive to proteinase K treatment of either protoplasts or whole cells.

John Locke and the Freedom of Belief

In 1686 William Penn gave John Locke a copy of Penn's Frame of Government for Pennsylvania, a constitution he had drafted hoping to establish Pennsylvania as a Christian utopia, but which the residents of the commonwealth had rejected four years earlier, to Penn's consternation. Locke did not find much to like in it either. One intriguing proposal it contained was a provision to erect and order all schools. Although Locke was interested in education—indeed during that very year he was advising friends on how to educate their son, advice he would later publish as popular thoughts on the subject—his reaction to that proposal could not have been more negative. Public education, he wrote in his journal, is the surest check upon liberty of conscience, suppressing all displeasing opinions in the bud.1 Today this sentiment probably seems absurd to many, especially considering the educational system in the United States. Public education is an important means for acquiring skills necessary not only for participation in our society but also for practicing true freedom of belief, since such freedom is hindered by ignorance and superstition, or so it is often thought. Aside from the question of whether schools typically replace some superstitions with others, this author suggests there is reason to question the claim that the United States' form of funding education, in which so-called public schools enjoy a nearly exclusive control over funds earmarked for education, is necessary, or even the best means, to achieve the ends for which compulsory education does seem necessary. The harm principle can be invoked to justify compulsory education. It requires further argument, however, to show that the United States' system of funding education is the best and most just. In the United States, one school system serves each educational district, funded by government at various levels, which is supposed to be sufficient for everyone regardless of race, religion, or creed;

William Penn's English Liberties: Tract for Several Times

JN i687, two years after setting up shop in Philadelphia, William Bradford printed a little book by William Penn, The Excellent Privilege of Liberty and Property, Being the Birthright of Freeborn Subjects of England. Penn's purpose in publishing this small book was to acquaint the settlers of his infant domain with their inestimable inheritance as freeborn Englishmen, and to help them understand how to preserve it from unjust and unreasonable men. To accomplish this purpose, Penn had the printer reproduce the first forty pages of English Liberties: or, The Freeborn Subject's Inheritance (i682),' adding as an appendix a copy of the Patent granted Penn by the king and a copy of the second Frame of Government Penn had drafted for the colony. Long attributed to Henry Care, an English journalist who gained notoriety as a chief publicist of the supposed Popish Plot of i678, there is good reason to believe that English Liberties was largely