338 research outputs found

    Challenges to the End-to-End Internet Model

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    In 1981 Saltzer, Reed, and Clark identified “end-to-end” principles related to the design of modern layered protocols. The Internet today is not as transparent as envisioned by [SALTZER81]. While most of the intelligence remains concentrated in end-systems, users are now deploying more sophisticated processing within the network for a variety of reasons including security, network management, E-commerce, and survivability. Applications and application-layer protocols have been found to interact in unexpected ways with this new intelligent software within the network such as proxies, address translators, packet filters, intrusion detection, and differentiated service functions. In this paper we survey examples of the problems caused by the introduction of this new processing within the network which is counter to the end-to-end Internet model proposed by [SALTZER81]. * 1 2 3 The conflict between the end-to-end Internet model and the introduction of new processing within the network is being addressed on a case-by-case basis in each development effort. There are no indications that new devices installed within the network (which break the end-to-end model) will disappear and in fact there has been dramatic growth in their implementation due to recent denial-ofservice attacks. Transition to IPv6 only solves a subset of these issues, and its deployment is proceeding slowly. Future work is obviously needed to create a consistent environment for protocol development that preserves the transparency provided by the end-to-end Internet model

    Software Submission using Client/Server Architecture in a Windows Network Environment

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    This paper describes a system for program submission using the client/server model. A Visual Basic front-end is combined with a C client to provide access to a C server

    Participative Decisions and Organizational Commitment: A Quantitative Analysis

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    William (Bill) H. Sumrall, Ed.D., is associate professor of business administration, Memphis campus, Belhaven College, Memphis, TN, 38137. David W. Cox, Ed.D., is professor of education, Arkansas State University, Jonesboro, AR, 72467. D. Adrian Doss, Ph.D.,is assistant professor of business administration, Memphis campus, Belhaven College, Memphis, TN, 38137. Don W. Jones, M.B.A., M.Div., is enrollment manager, Memphis campus, Belhaven College, Memphis, TN, 38137. Recipient, Best Paper Award, 28th Annual Southern Industrial Relations and Human Resource Conference (SIRHRC), Savannah, GA 31401

    Demographic correlations for 100 most-cited authors in ophthalmic research; a bibliometric study

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    Background: To analyze the academic characteristics, career trajectory, scholarly publications, and demographic background of the 100 most-cited authors in ophthalmic literature. Methods: In this observational cross-sectional study, a database containing every ophthalmology journal article from 1967 to 2018 was built using Scopus journal article information. The 100 authors with the most citations were identified, along with a control group of authors with at least five publications. Information about each author, such as gender, institution, and educational degrees were found from online web searches. Intra- and inter-group analyses were performed to identify correlations that may lead to having a high level of impact in ophthalmology literature. Results: Of the 100 most-cited ophthalmologists, 56 practice in the United States (US) and only 12 are female. In an odds ratio (OR) analysis, highly-cited researchers more often lived in the US (OR, 2.97; P < 0.001), were male (OR, 2.4; P = 0.02), and graduated from an elite medical school (OR, 3.89; P = 0.02) and/or residency (OR, 3.67; P = 0.02), but were not from an undergraduate institution (P = 0.75). There was no difference in citation numbers between different ophthalmology subspecialties (P = 0.22) or advanced degrees (PhD, MPH in addition to MD). Women among the top-100-cited authors were more likely to author high impact journal articles (P < 0.05). Conclusions: Among highly-cited ophthalmologists, practicing in the US and attending a top medical school or residency program may provide training for a successful research career in ophthalmology. Additionally, top female ophthalmologists participate in more influential research

    The 1995-1996 Decline of R Coronae Borealis - High Resolution Optical Spectroscopy

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    A set of high-resolution optical spectra of RCrB acquired before, during, and after its 1995-1996 decline is discussed. All of the components reported from earlier declines are seen. This novel dataset provides new information on these components including several aspects not previously seen in declines of RCrB and other RCBs. In the latter category is the discovery that the decline's onset is marked by distortions of absorption lines of high-excitation lines, and quickly followed by emission in these and in low excitation lines. This 'photospheric trigger' implies that dust causing the decline is formed close to the star. These emission lines fade quickly. After 1995 November 2, low excitation narrow (FWHM ~12 km s-1) emission lines remain. These appear to be a permanent feature, slightly blue-shifted from the systemic velocity, and unaffected by the decline except for a late and slight decrease of flux at minimum light. The location of the warm, dense gas providing these lines is uncertain. Absorption lines unaffected by overlying sharp emission are greatly broadened, weakened, and red-shifted at the faintest magnitudes when scattered light from the star is a greater contributor than direct light transmitted through the fresh soot cloud. A few broad lines are seen at and near minimum light with approxiamately constant flux: prominent among these are the He I triplet series, Na I D, and [N II] lines. These lines are blue-shifted by about 30 km s(-1) relative to the systemic velocity with no change in velocity over the several months for whicht he lines were seen. It is suggested that these lines, especially the He I lines, arise from an accretion disk around an unseen compact companion, which may be a low-mass white dwarf. If so, R CrB is similar to the unusual post-AGB star 89 Her.Comment: 31 pages, 26 figure

    Fast and flexible Kullback-Leibler divergence based acoustic modeling for non-native speech recognition

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    One of the main challenge in non-native speech recognition is how to handle acoustic variability present in multiaccented non-native speech with limited amount of training data. In this paper, we investigate an approach that addresses this challenge by using Kullback-Leibler divergence based hidden Markov models (KL-HMM). More precisely, the acoustic variability in the multi-accented speech is handled by using multilingual phoneme posterior probabilities, estimated by a multilayer perceptron trained on auxiliary data, as input feature for the KL-HMM system. With limited training data, we then build better acoustic models by exploiting the advantage that the KL-HMM system has fewer number of parameters. On HIWIRE corpus, the proposed approach yields a performance of 1.9% word error rate (WER) with 149 minutes of training data and a performance of 5.5% WER with 2 minutes of training data

    Investigating the Anti-tumorigenic Properties of Synthetic Inhibitors of B7-H3 in Group 3 Medulloblastoma

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    Medulloblastomas (MB) are devastating brain tumors originating in the cerebellum most commonly in children. There are four distinct subgroups of medulloblastoma: WNT (wingless), SHH (sonic hedgehog), group 3, and group 4. The most malignant tumors possess an aggressive phenotype characterized by c-Myc amplification and deletions to chromosome 17p; they belong to group 3. Prior investigations into the significance of genes on 17p revealed that miR-1253, which is found on locus 17p13.3, is significantly downregulated in medulloblastoma and has important tumor suppressive properties. Amongst its oncogenic targets is B7-H3 (CD276), a highly deregulated oncoprotein that attenuates the immune response to MB tumors. We chose to elucidate the oncogenic properties of B7-H3 in group 3 MB using synthetic inhibitors. After screening 100,000 different compounds for: 1) docking ability, 2) oral bioavailability, 3) potential CNS activity, and 4) number of metabolic side reactions, we selected two N-terminal inhibitors: B7-H3-Ni1 and B7-H3-Ni3. In HDMB03 cells (with c-Myc amplification and i17q), we found an IC50 of 3.7 M for B7-H3-Ni1 and no discernible effect of B7-H3-Ni3. We confirmed CD276 expression inhibition using B7-H3-Ni1 via Western blotting and concurrently noted elevations in cleaved PARP (apoptosis) and reduction in p-Akt (proliferation marker), providing us preliminary insights into the mechanism of inhibition. Notably, a remarkable decline in migration and wound healing and abrogation of colony formation were observed with B7-H3-Ni1. Collectively, our findings substantiate the inhibitory properties of B7-H3-Ni1 in vitro, potentially serving as a therapeutic agent for in vivo group 3 MB tumors.https://digitalcommons.unmc.edu/surp2021/1049/thumbnail.jp
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