Redundant Transfer Research Articles

Ammonium Salts: New Synergistic Additive for Chemical Vapor Deposition Growth of MoS2.

Controllable and scalable fabrication is the precondition for realizing the large number of superior electronic and catalytic applications of MoS2. Here, we report a new type of synergistic additives, ammonium salts, for chemical vapor deposition (CVD) growth of MoS2. On the basis of the catalysis of ammonium salts, we can achieve layer and shape-controlled MoS2 domains and centimeter-scale MoS2 films. Compared to frequently used alkali metal ions as the catalysts, ammonium salts are decomposed completely at low temperature (below 513 °C), resulting in clean and nondestructive as-grown substrates. Thus, MoS2 electronic devices can be directly fabricated on them, and the redundant transfer step is no longer needed. This method can also promote the direct growth of MoS2 on the conductive substrate and boost the improvement of hydrogen evolution reaction (HER) performance. The ammonium salt-mediated CVD method will pave a new way for MoS2 toward real applications in modern electronics and catalysis.

S^{2}ES: a stationary and scalable knowledge transfer approach for multiagent reinforcement learning

Knowledge transfer is widely adopted in accelerating multiagent reinforcement learning (MARL). To accelerate the learning speed of MARL for learning-from scratch agents, in this paper, we propose a Stationary and Scalable knowledge transfer approach based on Experience Sharing (S^{2}ES). The mainframe of our approach is structured into three components: what kind of experience, how to learn, and when to transfer. Specifically, we first design an augmented form of experience. By sharing (i.e., transmitting) the experience from one agent to its peers, the learning speed can be effectively enhanced with guaranteed scalability. A synchronized learning pattern is then adopted, which reduces the nonstationarity brought by experience replay, and at the same time retains data efficiency. Moreover, to avoid redundant transfer when the agents’ policies have converged, we further design two trigger conditions, one is modified Q value-based and another is normalized Shannon entropy-based, to determine when to conduct experience sharing. Empirical studies indicate that the proposed approach outperforms the other knowledge transfer methods in efficacy, efficiency, and scalability. We also provide ablation experiments to demonstrate the necessity of the key ingredients.

Identification, characterization and benefits of an exclusion system in an integrative and conjugative element of Bacillus subtilis.

Integrative and conjugative elements (ICEs) are mobile genetic elements that transfer from cell to cell by conjugation (like plasmids) and integrate into the chromosomes of bacterial hosts (like lysogenic phages or transposons). ICEs are prevalent in bacterial chromosomes and play a major role in bacterial evolution by promoting horizontal gene transfer. Exclusion prevents the redundant transfer of conjugative elements into host cells that already contain a copy of the element. Exclusion has been characterized mostly for conjugative elements of Gram-negative bacteria. Here, we report the identification and characterization of an exclusion mechanism in ICEBs1 from the Gram-positive bacterium Bacillus subtilis. We found that cells containing ICEBs1 inhibit the activity of the ICEBs1-encoded conjugation machinery in other cells. This inhibition (exclusion) was specific to the cognate conjugation machinery and the ICEBs1 gene yddJ was both necessary and sufficient to mediate exclusion by recipient cells. Through a mutagenesis and enrichment screen, we identified exclusion-resistant mutations in the ICEBs1 gene conG. Using genes from a heterologous but related ICE, we found that the exclusion specificity was determined by ConG and YddJ. Finally, we found that under conditions that support conjugation, exclusion provides a selective advantage to the element and its host cells.

Enhanced Redundancy of ST 2059-2 Time Transfer Over ST 2022-7 Redundant Networks

As the SMPTE ST 2059–2 standard for accurate time transfer enters real-world All-IP Studio deployments, it is important for broadcasters and system integrators to understand how the various parameters and options of the IEEE 1588 Precision Time Protocol (PTP) profile will impact both system performance and the network architecture for all media essence based on standardized IP transports, such as the recently adopted SMPTE ST 2110 series or AES67. Given the mission-critical nature of broadcast infrastructure, fully redundant networks are becoming a mandatory requirement. While ST 2022–7 defines a media essence redundancy model for switching between multiple identical flows on a per Realtime Transport Protocol (RTP) packet basis, such as it would apply to the SMPTE 2110 suite of standards, the IEEE 1588’s assumption of constant transmission delays would be violated by this approach, thus resulting in transient errors. The IEEE 1588 Precision Time Protocol (PTP) time transfer paradigm was not designed to be switched on a per PTP message basis. Although PTP has a certain level of redundancy built into the protocol to tolerate the loss of the time reference, it cannot utilize the advantages of redundant networks to their full extent. This paper addresses how the stability and availability of time and frequency transfer for SMPTE ST 2059–2 endpoints can be improved far beyond the basic redundancy mechanism provided by PTP if they are connected via separate paths toward the network as proposed in the SMPTE ST 2022–7 standard. For maximum utilization of multiple parallel channels for time transfer, PTP implementation requires additional enhancements. The solutions presented are complemented by comparative measurements demonstrating the improvements generated by such optimized designs, which includes the presence of common transient and permanent error conditions, thus showing the advantages of fully redundant time transfer over basic redundancy mechanisms provided by PTP.

Simulation model of local computer network with channel aggregation and random access method at redundant transfer

Simulation model of local computer network with channel aggregation and random access method at redundant transfer

Energy efficient clustering and routing in a wireless sensor networks

Wireless Sensor Network (WSN) is instrumental in transferring the data gathered by Sensors mounted on the Sensors Nodes (SNs) to the Base Station (BS). Lifetime of WSN is solely depends on the energy/battery life of SNs and higher the battery life longer the lifetime of Network. The sustained operation of WSN is achieved through the efficient consumption of SNs energy. In the recent past several energy conservation mechanism were proposed and among them LEACH-WSN was the most widespread methodology [1]. Further, the work pertaining to the sustained energy conservation mechanisms which are enriched with bio inspired technique or neural computational systems such as PSO-PSO-WSN, PSO-GSO-WSN, GSO-KGMO-WSN, FCM-PSO-GSO-WSN EBC-S or RSOM-WSN are reported [2-6]. In order to conserve energy in WSN; SNs are clustered using a set of criteria and gather the data at each Cluster Head (CH) to avoid redundant transfer of data to the BS. Further, gathered data is routed to the BS efficiently using intelligent routing process. In this paper, PSO-PSO-WSN, LEACH-WSN and EBC-S are compared with PSO-GSO-WSN, GSO-KGMO-WSN, FCM-PSO-GSO-WSN and RSOM-WSN. These methods are subjected to the Performance Evaluation (PE) in terms of alive nodes, dead nodes, energy consumption, throughput and total data/packet delivered.

ReWAP: Reducing Redundant Transfers for Mobile Web Browsing via App-Specific Resource Packaging

Redundant transfer of resources is a critical issue for compromising the performance of mobile Web applications (a.k.a., apps) in terms of data traffic, load time, and even energy consumption. Evidence demonstrates that the current cache mechanisms are far from satisfactory. With lessons learned from how native apps manage their resources, in this article, we present the ReWAP approach to fundamentally reducing redundant transfers by restructuring the resource loading of mobile Web apps. ReWAP is based on an efficient resource-packaging mechanism where stable resources are encapsulated and maintained into a package, and such a package shall be loaded always from the local storage and updated by explicitly refreshing. By retrieving and analyzing the update of resources, ReWAP maintains resource packages that can accurately identify which resources can be loaded from the local storage for a considerably long period. ReWAP also provides a wrapper for mobile Web apps to enable loading and updating resource packages in the local storage as well as loading resources from resource packages. ReWAP can be easily and seamlessly deployed into existing mobile Web architectures with minimal modifications, and is transparent to end-users. We evaluate ReWAP based on continuous 15-day access traces of 50 mobile Web apps randomly chosen from Alexa top 500 ranking list. Compared to the original mobile Web apps with cache enabled, ReWAP can significantly reduce the data traffic, with the median saving up to 51 percent. In addition, ReWAP can incur only very minor runtime overhead of the client-side browsers and thus does not compromise user experiences.

Demystifying the Imperfect Client-Side Cache Performance of Mobile Web Browsing

The web browser is one of the most significant applications on mobile devices such as smartphones. However, the user experience of mobile web browsing is undesirable because of the slow resource loading. To improve the performance of web resource loading, client-side cache has been adopted as a key mechanism. However, the existing passive measurement studies cannot comprehensively characterize the “ client-side ” cache performance of mobile web browsing. For example, most of these studies mainly focus on client-side implementations but not server-side configurations, suffer from biased user behaviors, and fail to study “ miscached ” resources. To address these issues, in this article, we present a proactive approach to making a comprehensive measurement study on client-side cache performance. The key idea of our approach is to proactively crawl resources from hundreds of websites periodically with a fine-grained time interval. Thus, we are able to uncover the resource update history and cache configurations at the server side, and analyze the cache performance in various time granularities. Based on our collected data, we build a new cache analysis model and study the upper bound of how high percentage of resources could potentially be cached and how effectively the caching works in practice. We report detailed analysis results of different websites and various types of web resources, and identify the problems caused by unsatisfactory cache performance. In particular, we identify two major problems— Redundant Transfer and Miscached Resource , which lead to unsatisfactory cache performance. We investigate three main root causes: Same Content , Heuristic Expiration , and Conservative Expiration Time , and discuss what mobile web developers can do to mitigate those problems.

Multipath state aware concurrent multipath transfer using redundant transmission for multi-homed hosts

Concurrent multipath transport protocols have the potential to improve significantly the throughput performance and resilience of the internet traffic flows. If the data transfer starts to the destined IP, unaware of paths condition, that may result in packet loss and delay in data transfer. This is due to bursty conditions of IP traffic or physical damage. To overcome this, status of the network path is determined before transmission. In our new mechanism multipath state aware concurrent multipath transfer using redundant transfer (MSACMT-RT), status of multipath is determined, initially and periodically before transmission. MSACMT-RT begins immediately after determining the path status, for a particular interval of time and later transfers data with CMT only for predefined period. We demonstrate using simulation under assumption that both the sender/receiver have three paths for CMT. By using MSACMT-RT, it is inferred that our algorithm outperforms better than concurrent multipath transfer potentially failed (CMT-PF). MSACMT-RT mechanism in alternate paths increases the throughput. We present and discuss MSACMT-RT performance in asymmetric paths with the constrained receiver buffer (RBUF) value of 128 KB. We also discuss this scenario with no path failures, frequent and on more frequent path failures with regular and irregular intervals.

Performance Metrics of Multipath State Aware Concurrent Multipath Transfer using Redundant Transfer in Stream Control Transmission Protocol Multihoming for Symmetric Paths

Problem statement: In multihomed host, if data transfer starts using CMT, unaware of paths status causes delay in data transfer or packet loss due to path failure. Transmission Path (one or more paths) failures result in out-of-order data delivery causing receiver buffer blocking and preventing sender from transmitting further data. Approach: Multipath State Aware Concurrent Multipath Transfer using Redundant Transfer (MSACMT-RT), status of multipath is determined, initially and periodically before transmission. Data transfer begins immediately after determining the path status, for a particular interval of time and later transfers with CMT only for predefined period. Results: We discuss MSACMT-RT performance in symmetric paths with the constrained receiver buffer (rbuf) value of 128 and 256KB’s. Our simulation result shows Percentage of throughput Increase between 5-15% for transfer of 20 and 40MB file sizes. Conclusion: By using MSACMT-RT we infer that our algorithm outperforms on par or better but never worse than Concurrent Multipath Transfer Potentially Failed (CMT-PF). MSACMT-RT mechanism in alternate paths increases the throughput during aggressive failures and Non-failure scenarios. Larger the file sizes of file transfer, greater the degree of throughput with less transfer time is achieved.

Entry exclusion in the IncHI1 plasmid R27 is mediated by EexA and EexB

Conjugative plasmids have evolved entry exclusion mechanisms to inhibit redundant DNA transfer from donor cells into recipients harboring isogenic or closely related plasmids. This exclusion phenomenon has been documented in the incompatibility H group (IncH) plasmid R27. A cosmid library representing the majority of the large (180kb) R27 plasmid was transformed into recipient cells and a conjugation assay identified that an operon located in the conjugative transfer region 2 (Tra2) of R27, the Z operon, mediated entry exclusion in the IncH plasmid. Reverse-transcriptase analysis revealed that the Z operon is comprised of four genes, 015, eexB, 017, and eexA. Sub-cloning of the individual genes located within the Z operon and subsequent screening for the entry exclusion phenotype determined that two genes, eexA and eexB, independently inhibit the entry of IncH-related plasmids. Bacterial fractionation studies predominantly localized the EexA protein to the cytoplasmic membrane, and the EexB protein to the outer membrane. Recipient cells expressing EexA and EexB were unable to exclude the entry of R27 plasmids harboring mutations within the IncH entry exclusion genes eexA and eexB. The IncH entry exclusion proteins EexA and EexB likely prevent redundant plasmid transfer by interaction with one another.

Interactions between Inner Membrane Proteins in Donor and Recipient Cells Limit Conjugal DNA Transfer

Conjugation enables horizontal transmission of DNA among bacteria, thereby facilitating the rapid spread of genes such as those conferring resistance to antibiotics. Cell-cell contact is required for conjugative DNA transfer but does not ensure its success. The presence of certain plasmids in potential recipient cells inhibits redundant transfer of these plasmids from competent donors despite contact between donor and recipient cells. Here, we used two closely related integrating conjugative elements (ICEs), SXT and R391, to identify genes that inhibit redundant conjugative transfer. Cells containing SXT exclude transfer of a second copy of SXT but not R391 and vice versa. The specific exclusion of SXT and R391 is dependent upon variants of TraG and Eex, ICE-encoded inner membrane proteins in donor and recipient cells, respectively. We identified short sequences within each variant that determine the exquisite specificity of self-recognition; these data suggest that direct interactions between TraG and Eex mediate exclusion.

Redundant homosexual F transfer facilitates selection-induced reversion of plasmid mutations

F plasmids use surface exclusion to prevent the redundant entry of additional F plasmids during active growth of the host cells. This mechanism is relaxed during stationary phase and nonlethal selections, allowing homosexual redundant plasmid transfer. Homosexual redundant transfer occurs in stationary-phase liquid cultures, within nongrowing populations on solid media, and on media lacking a carbon source. We examined the relationship between homosexual redundant transfer, which occurs between F+ hosts, and reversion of a plasmid-encoded lac mutant allele, lacI33omegalacZ. Sodium dodecyl sulfate (SDS) and mutations that prevent normal transfer to F- cells reduced redundant transfer and selection-induced reversion of the lacI33omegalacZ allele. A recA null mutation reduced redundant transfer and selection-induced reversion of the lacI33omegalacZ mutation. Conversely, a recD null mutation increased redundant transfer and selection-induced reversion of the lacI33omegalacZ allele. These results suggest an explanation for why SDS and these mutations affect reversion of the plasmid lacI33omegalacZ allele. However, a direct causal relationship between transfer and reversion remains to be established. These results suggest that Rec proteins play an active role in redundant transfer and/or that redundant transfer is regulated with the activation of recombination. Redundant homosexual plasmid transfer during a period of stress may represent a genetic response that facilitates evolution of plasmid-encoded functions through mutation, recombination, reassortment, and dissemination of genetic elements present in the populations.

Redundant transfer of F' plasmids occurs between Escherichia coli cells during nonlethal selections.

Surface exclusion is the mechanism by which F plasmids prevent the redundant entry of additional F plasmids into the host cell during exponential growth. This mechanism is relaxed in cells that are in stationary phase. Using genetically marked F' plasmids and host strains, we extend this finding to Escherichia coli populations during extended nonlethal selection in bacterial lawns. We show that a high level of redundant transfer occurs between these nongrowing cells during the selection. This result has implications for the mechanism of adaptive mutagenesis.

Participation of redundant transfer ribonucleic acids from yeast in protein synthesis.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParticipation of redundant transfer ribonucleic acids from yeast in protein synthesisP. L. Bergquist, D. J. W. Burns, and Carol A. PlinstonCite this: Biochemistry 1968, 7, 5, 1751–1761Publication Date (Print):May 1, 1968Publication History Published online1 May 2002Published inissue 1 May 1968https://doi.org/10.1021/bi00845a020RIGHTS & PERMISSIONSArticle Views19Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts