Science.gov

Sample records for ad hoc committees

  1. 21 CFR 14.90 - Ad hoc advisory committee members.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ad hoc advisory committee members. 14.90 Section... PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE Members of Advisory Committees § 14.90 Ad hoc advisory committee members. In selecting members of an ad hoc advisory committee, the Commissioner may use...

  2. 21 CFR 14.90 - Ad hoc advisory committee members.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ad hoc advisory committee members. 14.90 Section... PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE Members of Advisory Committees § 14.90 Ad hoc advisory committee members. In selecting members of an ad hoc advisory committee, the Commissioner may use...

  3. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Ad hoc committees. 1203.903 Section 1203.903... Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized to establish such ad hoc panels or subcommittees as may be necessary in the conduct of the Committee's work....

  4. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Ad hoc committees. 1203.903 Section 1203... NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized to establish such ad hoc panels or subcommittees as may be necessary in the conduct of the...

  5. 14 CFR § 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Ad hoc committees. § 1203.903 Section § 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is...

  6. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Ad hoc committees. 1203.903 Section 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized...

  7. 14 CFR 1203.903 - Ad hoc committees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Ad hoc committees. 1203.903 Section 1203.903 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM NASA Information Security Program Committee § 1203.903 Ad hoc committees. The Chairperson is authorized...

  8. Ad Hoc Technical Committee for Vocational Agriculture. Final Report.

    ERIC Educational Resources Information Center

    Indiana State Commission on Vocational and Technical Education, Indianapolis.

    The goal of the Ad Hoc Technical Committee for Vocational Agriculture in Indiana was to develop a model and recommendations that would result in improved student knowledge and skills for the present and future, address labor market needs, and promote program excellence at all levels of education. The committee developed recommendations for…

  9. 14 CFR § 1203.803 - Ad hoc committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Ad hoc committees. § 1203.803 Section § 1203.803 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Delegation of Authority To Make Determinations in Original Classification Matters § 1203.803 Ad...

  10. 14 CFR § 1203.1002 - Ad hoc committees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Ad hoc committees. § 1203.1002 Section § 1203.1002 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION INFORMATION SECURITY PROGRAM Special Access Programs (SAP) and Sensitive Compartmented Information (SCI) Programs...

  11. 29 CFR 1912.11 - Terms of ad hoc committee members.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Terms of ad hoc committee members. 1912.11 Section 1912.11..., DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.11 Terms of ad hoc committee members. Each member of an ad hoc advisory committee shall serve for such period as...

  12. 29 CFR 1912.11 - Terms of ad hoc committee members.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Terms of ad hoc committee members. 1912.11 Section 1912.11..., DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Organizational Matters § 1912.11 Terms of ad hoc committee members. Each member of an ad hoc advisory committee shall serve for such period as...

  13. Ad hoc committee on global climate issues: Annual report

    USGS Publications Warehouse

    Gerhard, L.C.; Hanson, B.M.B.

    2000-01-01

    The AAPG Ad Hoc Committee on Global Climate Issues has studied the supposition of human-induced climate change since the committee's inception in January 1998. This paper details the progress and findings of the committee through June 1999. At that time there had been essentially no geologic input into the global climate change debate. The following statements reflect the current state of climate knowledge from the geologic perspective as interpreted by the majority of the committee membership. The committee recognizes that new data could change its conclusions. The earth's climate is constantly changing owing to natural variability in earth processes. Natural climate variability over recent geological time is greater than reasonable estimates of potential human-induced greenhouse gas changes. Because no tool is available to test the supposition of human-induced climate change and the range of natural variability is so great, there is no discernible human influence on global climate at this time.

  14. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Designation of chairperson for Ad Hoc Committees... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  15. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Designation of chairperson for Ad Hoc Committees... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  16. Initial Report of the Deans Cyber Warfare Ad Hoc Committee

    DTIC Science & Technology

    2011-12-22

    in a cyber warfare environment. Among the more notable recent developments have been the establishment of a new Cyber Warfare Command (USCYBERCOM) at...information-warfare-centric organization. Clearly, future Naval Academy graduates will be expected to know more about cyber warfare than those we have...graduated in the past. The Academic Dean and Provost tasked an ad hoc committeethe Cyber Warfare ad hoc Committeeto examine how USNA can best ensure that

  17. Z306 molecular contamination ad hoc committee results

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L.

    1992-01-01

    LDEF external surfaces which did not receive significant amounts of atomic oxygen were observed to be coated with a brown contamination, apparently the result of a condensed organic residue darkened due to UV radiation exposure. During the initial Materials Special Investigation Group (MSIG) Meeting after LDEF deintegration, held in Seattle - July 1990, this organic contamination was the subject of much discussion. The amount of contamination was thought to be significant and its source was immediately believed to be the Z306 black thermal control coating used to coat the entire inner surface of LDEF. Due to the size of the structure, it was not feasible to bake-out the coating. However, initial data on the contamination film was confusing in that significant amounts of silicon was observed by several different researchers. Silicon (from silicone) was not expected to be a potential outgassing product of the Z306 polyurethane coating. To investigate the connection between external contamination and the interior paint, a MSIG ad hoc committee was formed.

  18. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  19. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  20. 32 CFR 2800.7 - Designation of chairperson for Ad Hoc Committees.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... VICE PRESIDENT OF THE UNITED STATES SECURITY PROCEDURES § 2800.7 Designation of chairperson for Ad Hoc Committees. The Counsel to the Vice President is designated as the responsible official to chair Ad...

  1. Panel Discussion : Report of the APS Ad-Hoc Committee on LGBT Issues

    NASA Astrophysics Data System (ADS)

    Atherton, Tim; Barthelemy, Ramon; Garmon, Savannah; Reeves, Kyle; APS Ad-Hoc Committee on LGBT Issues Team

    Following the presentation of the findings and recommendations of the APS Ad-Hoc Committee on LGBT Issues (C-LGBT) by Committee Chair Michael Falk, a panel discussion will be held featuring several members of the committee. The discussion will focus on how APS can best ensure the recommendations of the committee are carried out in a timely fashion and other ideas on future APS efforts toward LGBT inclusion in physics. Discussion topics will also include the research and other input that shaped the committee's findings and recommendations.

  2. Report of the AD HOC Committee on Patent Documentation.

    ERIC Educational Resources Information Center

    Urbach, Peter; And Others

    The Committee was established in September 1967 to study and make recommendations on Recommendation XXIX and XXX of the Report of the President's Commission on the Patent System. Based on interviews with Patent Office officials, patent examiners and classifiers and a review of Patent Office studies and documents, the Committee concluded that the…

  3. Report of the AD HOC Committee on Patent Documentation.

    ERIC Educational Resources Information Center

    Urbach, Peter; And Others

    The Committee was established in September 1967 to study and make recommendations on Recommendation XXIX and XXX of the Report of the President's Commission on the Patent System. Based on interviews with Patent Office officials, patent examiners and classifiers and a review of Patent Office studies and documents, the Committee concluded that the…

  4. Report of the ad hoc Committee on Women Studies, College of Arts and Sciences.

    ERIC Educational Resources Information Center

    Washington Univ., Seattle. Coll. of Arts and Sciences.

    The ad hoc Committee on Women Studies at the University of Washington recommends that a program of women's studies be instituted to permit rigorous academic study in the area. The program would be composed of: (1) an introductory core course; (2) four upper-division courses; (3) a significant amount of study (approximately 35 credits) in a single…

  5. Report of the Ad Hoc Committee on Religious and Cultural Celebrations in the Library.

    ERIC Educational Resources Information Center

    Rathemacher, Andree; Grubman, Sheila Black; Lahiri, Amar; Gilton, Donna; Sharif, Mohammed

    The charge of the University of Rhode Island's Ad Hoc Committee on Religious and Cultural Celebrations in the Library was to: investigate all opportunities for the library to educate the campus community about religious and cultural holidays; consider all the major religions of the world and the possibility of having displays for the symbols of…

  6. Report of ad hoc OTEC cold water pipe committee

    SciTech Connect

    Barr, R.; Giannotti, J.; Deuchler, W.; Scotti, R.; Stadter, J.; Walsh, J. P.; Weiss, R.

    1980-02-01

    Now that the design work on the pilot plant is scheduled to start in the near future, DOE has considered it essential that an overall look be taken at the cold water pipe design process. The VSE Corporation, in its role as a support contractor to DOE, was tasked to organize a small study group to answer the question, Where do we stand on the verification of the computer models of the cold water pipe response by experimental measurements. The committee has studied all the available results of the cold water pipe development program. This report summarizes those results. The development and present capabilities of the computer programs used to calculate the response of a cold water pipe attached to a platform under known at-sea conditions are discussed. The various cold water pipe designs that have been done using the computer programs are summarized. The experiments that have been conducted up to the present time to measure the response of cold water pipes at-sea and in experimental tanks are described. The results of these experiments are presented. The experimental results are compared with the predictions made with the analytical computer programs. Conclusions drawn as a result of this analysis are presented and some recommendations are made. (WHK)

  7. Standardization of positive controls in diagnostic immunohistochemistry: recommendations from the International Ad Hoc Expert Committee.

    PubMed

    Torlakovic, Emina E; Nielsen, Søren; Francis, Glenn; Garratt, John; Gilks, Blake; Goldsmith, Jeffrey D; Hornick, Jason L; Hyjek, Elizabeth; Ibrahim, Merdol; Miller, Keith; Petcu, Eugen; Swanson, Paul E; Zhou, Xiaoge; Taylor, Clive R; Vyberg, Mogens

    2015-01-01

    Diagnostic immunohistochemistry (dIHC) has been practiced for several decades, with an ongoing expansion of applications for diagnostic use, and more recently for detection of prognostic and predictive biomarkers. However, standardization of practice has yet to be achieved, despite significant advances in methodology. An Ad Hoc Expert Committee was formed to address the standardization of controls, which is a missing link in demonstrating and assuring standardization of the various components of dIHC. This committee has also developed a concept of immunohistochemistry critical assay performance controls that are intended to facilitate methodology transfer and harmonization in dIHC. Furthermore, the committee has clarified definitions of IHC assay sensitivity and specificity, with special emphasis on how these definitions apply to positive controls. Recommendations for "best laboratory practice" regarding positive controls for dIHC are specified. The first set of immunohistochemistry critical assay performance controls for several frequently used IHC stains or tests is also developed and presented.

  8. Report of the Ad-Hoc Combustion Research Facility Committee on Computational Resources for Combustion Research

    SciTech Connect

    McLean, W.J.

    1983-08-01

    This report was prepared by the Combustion Research Facility Ad Hoc Committee on Computational Resources for Combustion Research. The committee was asked by Peter L. Mattern to determine CRF computer needs for 1983 to 1988, including consideration of CRF support of computing needs of DOE-sponsored combustion research programs outside Sandia. In brief we find that advancing the understanding of the chemical and physical processes in combustion will require a rapidly increasing use of fast supercomputers with large memories. The acquisition and unclassified availability of such a machine at Sandia National Laboratories, Livermore, will be an important step in maintaining our international leadership in computational aspects of combustion research. Such a machine would also enable us to interact with other DOE sponsored researchers by providing them with access to a supercomputer and to our extensive combustion related software.

  9. Report of the APS Ad-Hoc Committee on LGBT Issues - Presentation of Findings and Recommendations

    NASA Astrophysics Data System (ADS)

    Long, Elena

    2016-03-01

    In 2014 the Executive Officer of the American Physical Society (APS), Kate Kirby, created an Ad-Hoc Committee on LGBT Issues (C-LGBT) charged with reporting on the obstacles to inclusion of LGBT physicists, a term which for the purpose of this report refers to persons who self-identify as lesbian, gay, bisexual, transgender, queer, questioning, intersex, or asexual, as well as other sexual and gender minorities. The full charge was as follows: ``The committee will advise the APS on the current status of LGBT issues in physics, provide recommendations for greater inclusion, and engage physicists in laying the foundation for a more inclusive physics community? More specifically, the committee will investigate LGBT representation in physics, assess the educational and professional climate in physics, recommend changes in policies and practices that impact LGBT physicists, and address other issues that affect inclusion.'' We will present the findings and recommendations of the C-LGBT final report, and a panel discussion will be held following the presentation to discuss the future of APS efforts toward LGBT inclusion in physics.

  10. Report of the APS Ad-Hoc Committee on LGBT Issues - Presentation of Findings and Recommendations

    NASA Astrophysics Data System (ADS)

    Falk, Michael

    In 2014 the Executive Officer of the American Physical Society (APS), Kate Kirby, created an Ad-Hoc Committee on LGBT Issues (C-LGBT) charged with reporting on the obstacles to inclusion of LGBT physicists, a term which for the purpose of this report refers to persons who self-identify as lesbian, gay, bisexual, transgender, queer, questioning, intersex, or asexual, as well as other sexual and gender minorities. The full charge was as follows: ``The committee will advise the APS on the current status of LGBT issues in physics, provide recommendations for greater inclusion, and engage physicists in laying the foundation for a more inclusive physics community. ?More specifically, the committee will investigate LGBT representation in physics, assess the educational and professional climate in physics, recommend changes in policies and practices that impact LGBT physicists, and address other issues that affect inclusion.'' We will present the findings and recommendations of the C-LGBT final report, and a panel discussion will be held following the presentation to discuss the future of APS efforts toward LGBT inclusion in physics.

  11. Osteoarthritis research priorities: a report from a EULAR ad hoc expert committee.

    PubMed

    Conaghan, Philip G; Kloppenburg, Margreet; Schett, Georg; Bijlsma, Johannes W J

    2014-08-01

    Osteoarthritis (OA) currently affects over 40 million Europeans, with its associated personal suffering and significant economic burden for health systems set to dramatically escalate in a rapidly ageing Europe. Given the very limited effective therapeutic options for OA, the European League Against Rheumatism (EULAR) created an ad hoc committee of OA researchers, clinicians and patients to consider a research agenda focussed on the areas of epidemiology, pathogenesis, imaging and biomarkers, and therapies. The committee deliberated and listed research needs in these areas and also established some cross-area priority themes: predictors of OA progression, especially where this might enable stratified interventions; understanding mechanisms of OA pain; improved understanding of tissue communication in a process where multiple tissue pathologies are common; developing concepts of, and consequently interventions for, early OA where both pain and structural processes may be more effectively targeted than in typical clinical presentations; and the need for new treatment strategies, with examples discussed on pathology-targeted therapies and optimal combinations of therapies. This research agenda should provide useful guidance for all researchers in this field and hopefully lead to improved OA care. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. The Role of Business in Education Reform: Blueprint for Action. Report of the Business Roundtable Ad Hoc Committee on Education.

    ERIC Educational Resources Information Center

    Business Roundtable, New York, NY.

    Because of the critical importance of education to the productivity and competitiveness of business, the Ad Hoc Committee on Education, comprised of senior executives from major corporations, was established in November 1987 to identify actions the Business Roundtable could take to improve the quality of elementary and secondary education in the…

  13. Federal Government Printing and Publishing: Policy Issues. Report of the Ad Hoc Advisory Committee on Revision of Title 44.

    ERIC Educational Resources Information Center

    Joint Committee on Printing, Washington, DC.

    Designed to present a better understanding of the government's system of printing and distributing information and to highlight problems, alternatives, and important policy questions, this report synthesizes 13 weeks of the Ad Hoc Advisory Committee hearings on six topics: (1) Administration of policy--who should establish and administer policy in…

  14. Report of the "MLA Bibliography" Scope and Overlap Committee, an ACRL Ad Hoc Committee.

    ERIC Educational Resources Information Center

    Association of Coll. and Research Libraries, Chicago, IL.

    The "MLA Bibliography" Scope and Overlap Committee was formed in response to a request from the Modern Language Association for librarians' assistance in examining the coverage and overlap between the "MLA International Bibliography" and other reference tools. This report contains the following 20 papers, prepared by the…

  15. Work, Family, and Community: Summary Proceedings of an Ad Hoc Committee.

    ERIC Educational Resources Information Center

    Hayes, Cheryl D., Ed.

    These proceedings contain summaries of five working group discussions and a discussion of suggestions for future research from an ad hoc meeting on Work, Family, and Community (Fedruary 21-22, 1980) in Washington, D.C. The meeting had these objectives: (1) to identify salient policy and research issues associated with changing patterns of labor…

  16. Work, Family, and Community: Summary Proceedings of an Ad Hoc Committee.

    ERIC Educational Resources Information Center

    Hayes, Cheryl D., Ed.

    These proceedings contain summaries of five working group discussions and a discussion of suggestions for future research from an ad hoc meeting on Work, Family, and Community (Fedruary 21-22, 1980) in Washington, D.C. The meeting had these objectives: (1) to identify salient policy and research issues associated with changing patterns of labor…

  17. International survey of vestibular rehabilitation therapists by the Barany Society Ad Hoc Committee on Vestibular Rehabilitation Therapy.

    PubMed

    Cohen, Helen S; Gottshall, Kim R; Graziano, Mariella; Malmstrom, Eva-Maj; Sharpe, Margaret H

    2009-01-01

    The goal of this study was to determine how occupational and physical therapists learn about vestibular rehabilitation therapy, their educational backgrounds, referral patterns, and their ideas about entry-level and advanced continuing education in vestibular rehabilitation therapy. The Barany Society Ad Hoc Committee for Vestibular Rehabilitation Therapy invited therapists around the world to complete an E-mail survey. Participants were either known to committee members or other Barany Society members, known to other participants, identified from their self-listings on the Internet, or volunteered after reading notices published in publications read by therapists. Responses were received from 133 therapists in 19 countries. They had a range of educational backgrounds, practice settings, and referral patterns. Few respondents had had any training about vestibular rehabilitation during their professional entry-level education. Most respondents learned about vestibular rehabilitation from continuing education courses, interactions with their colleagues, and reading. All of them endorsed the concept of developing standards and educating therapists about vestibular anatomy and physiology, vestibular diagnostic testing, vestibular disorders and current intervention strategies. Therefore, the Committee recommends the development of international standards for education and practice in vestibular rehabilitation therapy.

  18. Priorities in Community Services Research for the Northeast: A Report of the Ad Hoc Committee on Community Services. Publication No. 10.

    ERIC Educational Resources Information Center

    Northeast Regional Center for Rural Development, Ithaca, NY.

    Constituted to include research users, the ad hoc Committee on Community Services Research in the Northeast analyzed the problems and information needs of community service personnel during a conference session. Issues and questions derived from this initial interchange were categorized and then translated into research problems. Criteria employed…

  19. Preserving Nevada's Environmental Heritage: A Report of the Ad Hoc Committee on Environmental Quality. Final Report to the Governor's Natural Resources Council.

    ERIC Educational Resources Information Center

    Nevada State Dept. of Conservation and Natural Resources, Carson City.

    The Environmental Quality Ad Hoc Committee has prepared this report for the Governor's Natural Resources Council (Nevada). It is a compilation of available factual data focusing attention on needed statutory and administrative changes to preserve Nevada's environmental heritage and from which recommendations for future budgetary and legislative…

  20. Meeting the Needs of CALS Students for Computing Capabilities. Final Report of the Ad Hoc Committee on College of Agriculture and Life Sciences Student Computing Competencies.

    ERIC Educational Resources Information Center

    Monk, David; And Others

    The Ad Hoc Committee on the Cornell University (New York) College of Agriculture and Life Sciences (CALS) Student Computing Competencies was appointed in the fall of 1995 to determine (1) what all CALS undergraduate students should know about computing and related technologies; (2) how the college can make it possible for students to develop these…

  1. Ad Hoc Committee on the Role of Students in the Government of the University. Report to the University Committee.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison.

    This committee report examines past student participation in the government of the University of Wisconsin, formulates principles concerning the role of students, and recommends structural and functional changes to achieve greater student participation. Except for the establishment of certain new committees, the report recommends changes within…

  2. Sputnik: ad hoc distributed computation.

    PubMed

    Völkel, Gunnar; Lausser, Ludwig; Schmid, Florian; Kraus, Johann M; Kestler, Hans A

    2015-04-15

    In bioinformatic applications, computationally demanding algorithms are often parallelized to speed up computation. Nevertheless, setting up computational environments for distributed computation is often tedious. Aim of this project were the lightweight ad hoc set up and fault-tolerant computation requiring only a Java runtime, no administrator rights, while utilizing all CPU cores most effectively. The Sputnik framework provides ad hoc distributed computation on the Java Virtual Machine which uses all supplied CPU cores fully. It provides a graphical user interface for deployment setup and a web user interface displaying the current status of current computation jobs. Neither a permanent setup nor administrator privileges are required. We demonstrate the utility of our approach on feature selection of microarray data. The Sputnik framework is available on Github http://github.com/sysbio-bioinf/sputnik under the Eclipse Public License. hkestler@fli-leibniz.de or hans.kestler@uni-ulm.de Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Proceedings of the Censorship Conference of the National Ad Hoc Committee Against Censorship (Dec. 9, 1975, New York City); A Day Long Discussion of Three Threats to the First Amendment and How Organizations Can Respond.

    ERIC Educational Resources Information Center

    National Ad Hoc Committee Against Censorship, New York, NY.

    The contents of this document consist of a transcript of the 1975 Censorship Conference proceedings, a list of conference participants, an outline of the National Ad Hoc Committee against Censorship, a statement of concern, and three appendixes. Contents of the transcript include introductory remarks by William F. Fore; a welcoming address by Dave…

  4. Trust Based Routing in Ad Hoc Network

    NASA Astrophysics Data System (ADS)

    Talati, Mikita V.; Valiveti, Sharada; Kotecha, K.

    Ad Hoc network often termed as an infrastructure-less, self- organized or spontaneous network.The execution and survival of an ad-hoc network is solely dependent upon the cooperative and trusting nature of its nodes. However, this naive dependency on intermediate nodes makes the ad-hoc network vulnerable to passive and active attacks by malicious nodes and cause inflict severe damage. A number of protocols have been developed to secure ad-hoc networks using cryptographic schemes, but all rely on the presence of trust authority. Due to mobility of nodes and limitation of resources in wireless network one interesting research area in MANET is routing. This paper offers various trust models and trust based routing protocols to improve the trustworthiness of the neighborhood.Thus it helps in selecting the most secure and trustworthy route from the available ones for the data transfer.

  5. Anomaly Detection Techniques for Ad Hoc Networks

    ERIC Educational Resources Information Center

    Cai, Chaoli

    2009-01-01

    Anomaly detection is an important and indispensable aspect of any computer security mechanism. Ad hoc and mobile networks consist of a number of peer mobile nodes that are capable of communicating with each other absent a fixed infrastructure. Arbitrary node movements and lack of centralized control make them vulnerable to a wide variety of…

  6. Anomaly Detection Techniques for Ad Hoc Networks

    ERIC Educational Resources Information Center

    Cai, Chaoli

    2009-01-01

    Anomaly detection is an important and indispensable aspect of any computer security mechanism. Ad hoc and mobile networks consist of a number of peer mobile nodes that are capable of communicating with each other absent a fixed infrastructure. Arbitrary node movements and lack of centralized control make them vulnerable to a wide variety of…

  7. Hearings before the Ad Hoc Committee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries, Ninety-Third Congress; Second Session on Officer Requirements, and Session on Maritime Education Regarding Safety at Sea. Serial No. 93-44.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

    The publication consists of Congressional hearings before the Ad Hoc Committee on Maritime Education and Training: (1) June 26, 1974 hearing pertaining to officer requirements and (2) November 19, 1974 hearing on maritime education regarding safety at sea. Estimated cost per graduate for the U. S. Merchant Marine 1973 class was $31,100. Supply and…

  8. Hearings before the Ad Hoc Committee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries, Ninety-Third Congress; Second Session on Officer Requirements, and Session on Maritime Education Regarding Safety at Sea. Serial No. 93-44.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

    The publication consists of Congressional hearings before the Ad Hoc Committee on Maritime Education and Training: (1) June 26, 1974 hearing pertaining to officer requirements and (2) November 19, 1974 hearing on maritime education regarding safety at sea. Estimated cost per graduate for the U. S. Merchant Marine 1973 class was $31,100. Supply and…

  9. Quantum load balancing in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Hasanpour, M.; Shariat, S.; Barnaghi, P.; Hoseinitabatabaei, S. A.; Vahid, S.; Tafazolli, R.

    2017-06-01

    This paper presents a novel approach in targeting load balancing in ad hoc networks utilizing the properties of quantum game theory. This approach benefits from the instantaneous and information-less capability of entangled particles to synchronize the load balancing strategies in ad hoc networks. The quantum load balancing (QLB) algorithm proposed by this work is implemented on top of OLSR as the baseline routing protocol; its performance is analyzed against the baseline OLSR, and considerable gain is reported regarding some of the main QoS metrics such as delay and jitter. Furthermore, it is shown that QLB algorithm supports a solid stability gain in terms of throughput which stands a proof of concept for the load balancing properties of the proposed theory.

  10. Supporting Dynamic Ad hoc Collaboration Capabilities

    SciTech Connect

    Agarwal, Deborah A.; Berket, Karlo

    2003-07-14

    Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment.

  11. DAWN: Dynamic Ad-hoc Wireless Network

    DTIC Science & Technology

    2016-06-19

    wireless communication networks . To accomplish this, DAWN adopts a very different approach than those followed in the past and summarized above. DAWN...wireless communication networks . The members of DAWN investigated difference aspects of wireless mobile ad hoc networks (MANET). The views, opinions and/or... communication networks . To accomplish this, DAWN adopts a very different approach than those followed in the past and summarized above. DAWN

  12. An evidence-based unified definition of lifelong and acquired premature ejaculation: report of the second international society for sexual medicine ad hoc committee for the definition of premature ejaculation.

    PubMed

    Serefoglu, Ege Can; McMahon, Chris G; Waldinger, Marcel D; Althof, Stanley E; Shindel, Alan; Adaikan, Ganesh; Becher, Edgardo F; Dean, John; Giuliano, Francois; Hellstrom, Wayne Jg; Giraldi, Annamaria; Glina, Sidney; Incrocci, Luca; Jannini, Emmanuele; McCabe, Marita; Parish, Sharon; Rowland, David; Segraves, R Taylor; Sharlip, Ira; Torres, Luiz Otavio

    2014-06-01

    The International Society for Sexual Medicine (ISSM) Ad Hoc Committee for the Definition of Premature Ejaculation developed the first evidence-based definition for lifelong premature ejaculation (PE) in 2007 and concluded that there were insufficient published objective data at that time to develop a definition for acquired PE. The aim of this article is to review and critique the current literature and develop a contemporary, evidence-based definition for acquired PE and/or a unified definition for both lifelong and acquired PE. In April 2013, the ISSM convened a second Ad Hoc Committee for the Definition of Premature Ejaculation in Bangalore, India. The same evidence-based systematic approach to literature search, retrieval, and evaluation used by the original committee was adopted. The committee unanimously agreed that men with lifelong and acquired PE appear to share the dimensions of short ejaculatory latency, reduced or absent perceived ejaculatory control, and the presence of negative personal consequences. Men with acquired PE are older, have higher incidences of erectile dysfunction, comorbid disease, and cardiovascular risk factors, and have a longer intravaginal ejaculation latency time (IELT) as compared with men with lifelong PE. A self-estimated or stopwatch IELT of 3 minutes was identified as a valid IELT cut-off for diagnosing acquired PE. On this basis, the committee agreed on a unified definition of both acquired and lifelong PE as a male sexual dysfunction characterized by (i) ejaculation that always or nearly always occurs prior to or within about 1 minute of vaginal penetration from the first sexual experience (lifelong PE) or a clinically significant and bothersome reduction in latency time, often to about 3 minutes or less (acquired PE); (ii) the inability to delay ejaculation on all or nearly all vaginal penetrations; and (iii) negative personal consequences, such as distress, bother, frustration, and/or the avoidance of sexual intimacy. The

  13. An Evidence-Based Unified Definition of Lifelong and Acquired Premature Ejaculation: Report of the Second International Society for Sexual Medicine Ad Hoc Committee for the Definition of Premature Ejaculation

    PubMed Central

    Serefoglu, Ege Can; McMahon, Chris G; Waldinger, Marcel D; Althof, Stanley E; Shindel, Alan; Adaikan, Ganesh; Becher, Edgardo F; Dean, John; Giuliano, Francois; Hellstrom, Wayne JG; Giraldi, Annamaria; Glina, Sidney; Incrocci, Luca; Jannini, Emmanuele; McCabe, Marita; Parish, Sharon; Rowland, David; Segraves, R Taylor; Sharlip, Ira; Torres, Luiz Otavio

    2014-01-01

    Introduction The International Society for Sexual Medicine (ISSM) Ad Hoc Committee for the Definition of Premature Ejaculation developed the first evidence-based definition for lifelong premature ejaculation (PE) in 2007 and concluded that there were insufficient published objective data at that time to develop a definition for acquired PE. Aim The aim of this article is to review and critique the current literature and develop a contemporary, evidence-based definition for acquired PE and/or a unified definition for both lifelong and acquired PE. Methods In April 2013, the ISSM convened a second Ad Hoc Committee for the Definition of Premature Ejaculation in Bangalore, India. The same evidence-based systematic approach to literature search, retrieval, and evaluation used by the original committee was adopted. Results The committee unanimously agreed that men with lifelong and acquired PE appear to share the dimensions of short ejaculatory latency, reduced or absent perceived ejaculatory control, and the presence of negative personal consequences. Men with acquired PE are older, have higher incidences of erectile dysfunction, comorbid disease, and cardiovascular risk factors, and have a longer intravaginal ejaculation latency time (IELT) as compared with men with lifelong PE. A self-estimated or stopwatch IELT of 3 minutes was identified as a valid IELT cut-off for diagnosing acquired PE. On this basis, the committee agreed on a unified definition of both acquired and lifelong PE as a male sexual dysfunction characterized by (i) ejaculation that always or nearly always occurs prior to or within about 1 minute of vaginal penetration from the first sexual experience (lifelong PE) or a clinically significant and bothersome reduction in latency time, often to about 3 minutes or less (acquired PE); (ii) the inability to delay ejaculation on all or nearly all vaginal penetrations; and (iii) negative personal consequences, such as distress, bother, frustration, and/or the

  14. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2008-08-01

    Maximization in Multi-User, MIMO Channels with Linear Processing...58 2.9 Using Feedback in Ad Hoc Networks....................................................................65 2.10 Feedback MIMO ...in MIMO Ad Hoc Interference Networks.......................................................................................................75 2.12

  15. AD Hoc Study on Human Robot Interface Issues

    DTIC Science & Technology

    2002-09-01

    ARMY SCIENCE BOARD AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES FINAL REPORT SEPTEMBER 2002 Distribution: Approved for...conclusions contained in this report are those of the 2002 Ad Hoc Study Panel on “Human- Robot Interface Issues” and do not necessarily reflect the official...DATES COVERED Army Science Board – 2002 Ad Hoc Study 4. TITLE AND SUBTITLE AD HOC STUDY ON HUMAN ROBOT INTERFACE ISSUES 6. AUTHOR(S) Study

  16. Ad Hoc Classification of Radiology Reports

    PubMed Central

    Aronow, David B.; Fangfang, Feng; Croft, W. Bruce

    1999-01-01

    Objective: The task of ad hoc classification is to automatically place a large number of text documents into nonstandard categories that are determined by a user. The authors examine the use of statistical information retrieval techniques for ad hoc classification of dictated mammography reports. Design: The authors' approach is the automated generation of a classification algorithm based on positive and negative evidence that is extracted from relevance-judged documents. Test documents are sorted into three conceptual bins: membership in a user-defined class, exclusion from the user-defined class, and uncertain. Documentation of absent findings through the use of negation and conjunction, a hallmark of interpretive test results, is managed by expansion and tokenization of these phrases. Measurements: Classifier performance is evaluated using a single measure, the F measure, which provides a weighted combination of recall and precision of document sorting into true positive and true negative bins. Results: Single terms are the most effective text feature in the classification profile, with some improvement provided by the addition of pairs of unordered terms to the profile. Excessive iterations of automated classifier enhancement degrade performance because of overtraining. Performance is best when the proportions of relevant and irrelevant documents in the training collection are close to equal. Special handling of negation phrases improves performance when the number of terms in the classification profile is limited. Conclusions: The ad hoc classifier system is a promising approach for the classification of large collections of medical documents. NegExpander can distinguish positive evidence from negative evidence when the negative evidence plays an important role in the classification. PMID:10495099

  17. [Health evaluation of trichloroethylene in indoor air : communication from the German ad-hoc working group on indoor guidelines of the Indoor Air Hygiene Committee and of the states' supreme health authorities].

    PubMed

    2015-07-01

    In the European Hazardous Substances Regulation No 1272/2008 trichloroethylene has been classified as a probable human carcinogen and a suspected mutagen. According to several Committees (German Committee on Hazardous Substances, European Scientific Committee on Occupational Exposure Limits, European Chemicals Agency´s Committee for Risk Assessment (ECHA-RAC)) concentrations of trichloroethylene cytotoxic to renal tubuli may increase the risk to develop renal cancer. At non-cytotoxic concentrations of trichloroethylene a much lower cancer risk may be assumed. Therefore, evaluating the cancer risk to the public following inhalation of trichloroethylene ECHA-RAC has assumed a sublinear exposure-response relationship for carcinogenicity of trichloroethylene. Specifically, ECHA-RAC assessed a cancer risk of 6.4 × 10(- 5) (mg/m(3))(- 1) following life time exposure to trichloroethylene below a NOAEC for renal cytotoxicity of 6 mg trichloroethylene/m(3). Further evaluation yields a life-time risk of 10(- 6) corresponding to 0.02 mg trichloroethylene/m(3). This concentration is well above the reference (e.g. background) concentration of trichloroethylene in indoor air. Consequently the Ad-hoc Working Group on Indoor Guidelines recommends 0.02 mg trichloroethylene/m(3) as a risk-related guideline for indoor air. Measures to reduce exposure are considered inappropriate at concentrations below this guideline.

  18. An evidence-based unified definition of lifelong and acquired premature ejaculation: report of the second International Society for Sexual Medicine Ad Hoc Committee for the Definition of Premature Ejaculation.

    PubMed

    Serefoglu, Ege Can; McMahon, Chris G; Waldinger, Marcel D; Althof, Stanley E; Shindel, Alan; Adaikan, Ganesh; Becher, Edgardo F; Dean, John; Giuliano, Francois; Hellstrom, Wayne J G; Giraldi, Annamaria; Glina, Sidney; Incrocci, Luca; Jannini, Emmanuele; McCabe, Marita; Parish, Sharon; Rowland, David; Segraves, R Taylor; Sharlip, Ira; Torres, Luiz Otavio

    2014-06-01

    The International Society for Sexual Medicine (ISSM) Ad Hoc Committee for the Definition of Premature Ejaculation developed the first evidence-based definition for lifelong premature ejaculation (PE) in 2007 and concluded that there were insufficient published objective data at that time to develop a definition for acquired PE. The aim of this article is to review and critique the current literature and develop a contemporary, evidence-based definition for acquired PE and/or a unified definition for both lifelong and acquired PE. In April 2013, the ISSM convened a second Ad Hoc Committee for the Definition of Premature Ejaculation in Bangalore, India. The same evidence-based systematic approach to literature search, retrieval, and evaluation used by the original committee was adopted. The committee unanimously agreed that men with lifelong and acquired PE appear to share the dimensions of short ejaculatory latency, reduced or absent perceived ejaculatory control, and the presence of negative personal consequences. Men with acquired PE are older, have higher incidences of erectile dysfunction, comorbid disease, and cardiovascular risk factors, and have a longer intravaginal ejaculation latency time (IELT) as compared with men with lifelong PE. A self-estimated or stopwatch IELT of 3 minutes was identified as a valid IELT cut-off for diagnosing acquired PE. On this basis, the committee agreed on a unified definition of both acquired and lifelong PE as a male sexual dysfunction characterized by (i) ejaculation that always or nearly always occurs prior to or within about 1 minute of vaginal penetration from the first sexual experience (lifelong PE) or a clinically significant and bothersome reduction in latency time, often to about 3 minutes or less (acquired PE); (ii) the inability to delay ejaculation on all or nearly all vaginal penetrations; and (iii) negative personal consequences, such as distress, bother, frustration, and/or the avoidance of sexual intimacy. The

  19. Worm epidemics in wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Nekovee, Maziar

    2007-06-01

    A dramatic increase in the number of computing devices with wireless communication capability has resulted in the emergence of a new class of computer worms which specifically target such devices. The most striking feature of these worms is that they do not require Internet connectivity for their propagation but can spread directly from device to device using a short-range radio communication technology, such as WiFi or Bluetooth. In this paper, we develop a new model for epidemic spreading of these worms and investigate their spreading in wireless ad hoc networks via extensive Monte Carlo simulations. Our studies show that the threshold behaviour and dynamics of worm epidemics in these networks are greatly affected by a combination of spatial and temporal correlations which characterize these networks, and are significantly different from the previously studied epidemics in the Internet.

  20. Cooperative Multi-Agent Systems in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2006-01-01

    COOPERATIVE MULTI - AGENT SYSTEMS IN MOBILE AD HOC NETWORKS Joseph P. Macker William Chao Myriam Abramson Ian Downard Information Technology Division...are, mobile ad hoc networking (MANET) and Multi - Agent Systems (MAS). Despite their value in enabling more autonomous network system operation...2006 to 00-00-2006 4. TITLE AND SUBTITLE Cooperative Multi - Agent Systems in Mobile Ad Hoc Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  1. Receiver-Based Ad Hoc On Demand Multipath Routing Protocol for Mobile Ad Hoc Networks

    PubMed Central

    Al-Nahari, Abdulaziz; Mohamad, Mohd Murtadha

    2016-01-01

    Decreasing the route rediscovery time process in reactive routing protocols is challenging in mobile ad hoc networks. Links between nodes are continuously established and broken because of the characteristics of the network. Finding multiple routes to increase the reliability is also important but requires a fast update, especially in high traffic load and high mobility where paths can be broken as well. The sender node keeps re-establishing path discovery to find new paths, which makes for long time delay. In this paper we propose an improved multipath routing protocol, called Receiver-based ad hoc on demand multipath routing protocol (RB-AOMDV), which takes advantage of the reliability of the state of the art ad hoc on demand multipath distance vector (AOMDV) protocol with less re-established discovery time. The receiver node assumes the role of discovering paths when finding data packets that have not been received after a period of time. Simulation results show the delay and delivery ratio performances are improved compared with AOMDV. PMID:27258013

  2. Spontaneous Ad Hoc Mobile Cloud Computing Network

    PubMed Central

    Lacuesta, Raquel; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes. PMID:25202715

  3. Spontaneous ad hoc mobile cloud computing network.

    PubMed

    Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

    2014-01-01

    Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

  4. Criteria for the diagnosis of heat-related deaths: National Association of Medical Examiners. Position paper. National Association of Medical Examiners Ad Hoc Committee on the Definition of Heat-Related Fatalities.

    PubMed

    Donoghue, E R; Graham, M A; Jentzen, J M; Lifschultz, B D; Luke, J L; Mirchandani, H G

    1997-03-01

    The National Association of Medical Examiners Ad Hoc Committee on the Definition of Heat-Related Fatalities recommends the following definition of "heat-related death": a death in which exposure to high ambient temperature either caused the death or significantly contributed to it. The committee also recommends that the diagnosis of heat-related death be based on a history of exposure to high ambient temperature and the reasonable exclusion of other causes of hyperthermia. The diagnosis may be established from the circumstances surrounding the death, investigative reports concerning environmental temperature, and/or measured antemortem body temperature at the time of collapse. In cases where the measured antemortem body temperature at the time of collapse was > or = 105 degrees F (> or = 40.6 degrees C), the cause of death should be certified as heat stroke or hyperthermia. Deaths may also be certified as heat stroke or hyperthermia with lower body temperatures when cooling has been attempted prior to arrival at the hospital and/or when there is a clinical history of mental status changes and elevated liver and muscle enzymes. In cases where the antemortem body temperature cannot be established but the environmental temperature at the time of collapse was high, an appropriate heat-related diagnosis should be listed as the cause of death or as a significant contributing condition.

  5. Ad hoc vs. Non-ad hoc Percutaneous Coronary Intervention Strategies in Patients With Stable Coronary Artery Disease.

    PubMed

    Toyota, Toshiaki; Morimoto, Takeshi; Shiomi, Hiroki; Ando, Kenji; Ono, Koh; Shizuta, Satoshi; Kato, Takao; Saito, Naritatsu; Furukawa, Yutaka; Nakagawa, Yoshihisa; Horie, Minoru; Kimura, Takeshi

    2017-03-24

    Few studies have evaluated the prevalence and clinical outcomes of ad hoc percutaneous coronary intervention (PCI), performing diagnostic coronary angiography and PCI in the same session, in stable coronary artery disease (CAD) patients.Methods and Results:From the CREDO-Kyoto PCI/CABG registry cohort-2, 6,943 patients were analyzed as having stable CAD and undergoing first PCI. Ad hoc PCI and non-ad hoc PCI were performed in 1,722 (24.8%) and 5,221 (75.1%) patients, respectively. The cumulative 5-year incidence and adjusted risk for all-cause death were not significantly different between the 2 groups (15% vs. 15%, P=0.53; hazard ratio: 1.15, 95% confidence interval: 0.98-1.35, P=0.08). Ad hoc PCI relative to non-ad hoc PCI was associated with neutral risk for myocardial infarction, any coronary revascularization, and bleeding, but was associated with a trend towards lower risk for stroke (hazard ratio: 0.78, 95% confidence interval: 0.60-1.02, P=0.06). Ad hoc PCI in stable CAD patients was associated with at least comparable 5-year clinical outcomes as with non-ad hoc PCI. Considering patients' preference and the cost-saving, the ad hoc PCI strategy might be a safe and attractive option for patients with stable CAD, although the prevalence of ad hoc PCI was low in the current study population.

  6. Assured Resource Sharing in Ad-Hoc Collaboration

    SciTech Connect

    Ahn, Gail-Joon

    2015-12-19

    The project seeks an innovative framework to enable users to access and selectively share resources in distributed environments, enhancing the scalability of information sharing. We have investigated secure sharing & assurance approaches for ad-hoc collaboration, focused on Grids, Clouds, and ad-hoc network environments.

  7. Assured Information Sharing for Ad-Hoc Collaboration

    ERIC Educational Resources Information Center

    Jin, Jing

    2009-01-01

    Collaborative information sharing tends to be highly dynamic and often ad hoc among organizations. The dynamic natures and sharing patterns in ad-hoc collaboration impose a need for a comprehensive and flexible approach to reflecting and coping with the unique access control requirements associated with the environment. This dissertation…

  8. Assured Information Sharing for Ad-Hoc Collaboration

    ERIC Educational Resources Information Center

    Jin, Jing

    2009-01-01

    Collaborative information sharing tends to be highly dynamic and often ad hoc among organizations. The dynamic natures and sharing patterns in ad-hoc collaboration impose a need for a comprehensive and flexible approach to reflecting and coping with the unique access control requirements associated with the environment. This dissertation…

  9. IPv6 Autoconfiguration for Mobile Ad-Hoc Networks: AUTOLSR

    DTIC Science & Technology

    2010-09-01

    IPv6 Autoconfiguration for Mobile Ad-Hoc Networks: AUTOLSR Cédric Adjih1, Amina Meraihi1, Pascale Minet1 and Thierry Plesse2 1Hipercom Project-Team...September 2010 « IPv6 Autoconfiguration for Mobile Ad-Hoc Networks AUTOLSR » Cedric Adjih1, Amina Meraihi1, Pascale Minet1 and Thierry Plesse2

  10. Enhanced Weight based DSR for Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Verma, Samant; Jain, Sweta

    2011-12-01

    Routing in ad hoc network is a great problematic, since a good routing protocol must ensure fast and efficient packet forwarding, which isn't evident in ad hoc networks. In literature there exists lot of routing protocols however they don't include all the aspects of ad hoc networks as mobility, device and medium constraints which make these protocols not efficient for some configuration and categories of ad hoc networks. Thus in this paper we propose an improvement of Weight Based DSR in order to include some of the aspects of ad hoc networks as stability, remaining battery power, load and trust factor and proposing a new approach Enhanced Weight Based DSR.

  11. [Indoor air guide values for naphthalene and naphthalene-like compounds. Announcement of the German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities].

    PubMed

    2013-10-01

    The German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities is issuing indoor air guide values to protect public health. Naphthalene is a potentially volatile two-ring hydrocarbon with a mothball-like odor. Indoor air contaminations usually originate from tar-containing building products, sometimes from the use of mothballs. In Germany, indoor air concentrations of naphthalene are usually low, near the detection limit (medians of about 0.001 mg/m3, 95th percentiles up to 0.004 mg/m3). Naphthalene-like volatile compounds have been defined to cover methyl- and dimethylnaphthalenes and tricyclic aromatic hydrocarbons (e.g., acenaphthene, acenaphthylene, anthracene, fluorene and phenanthrene). Though methylnaphthalenes and dimethylnaphthalenes usually show low indoor air concentrations, they have been suspected to add to the mothball-like odor. Tricyclic aromatic hydrocarbons mostly occur below 0.001 mg/m3 of indoor air. Against this background naphthalene is seen to be the key component of this group of substances in indoor air. No valid human data is available with respect to health effects of inhaled naphthalene. Based on animal data cytotoxic-inflammatory lesions in the rat nasal epithelium are regarded as the critical endpoint. In a subchronic inhalation study in rats (Dodd et al., Inhal Toxicol 24:70–79, 2012), minimal effects were observed following an exposure to 5 mg naphthalene/m3. From this study the Ad-hoc Working Group derived a chronic NAEC of 2.5 mg naphthalene/m3. Time scaling was considered by a factor of 5.6 extrapolating from 6 to 24 h and 5 to 7 days, a factor of 2 applied for the use of F344 rats instead of the more sensitive Sprague-Dawley rats. Incorporating an interspecies factor of 1, an intraspecies factor of 10 and a factor of 2 for insufficient data on the toxicity of naphthalene in children resulted in a precautionary value of 0.01 mg naphthalene/m3 and a hazard

  12. [Indoor air guide values for acetaldehyde. Announcement of the German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities].

    PubMed

    2013-10-01

    The German Ad-hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and the States' Supreme Health Authorities is issuing indoor air guide values to protect public health. No suitable human studies are available for health evaluation of acetaldehyde in indoor air. In a well-documented subchronic inhalation animal study with rats assessed as reliable, local irritation effects were observed in nasal epithelia, most prominently in the olfactory epithelium with loss of olfactory neuronal cells. This study leads to a LOAEC of 48 mg acetaldehyde/m3 for continuous exposure for the endpoint nasal epithelium degeneration. By applying an interspecies factor of 1, a factor of 10 for interindividual variability, and a factor of 2 to account for the higher respiratory rate of children compared to adults, a health hazard guide value (RW II) of 1 mg acetaldehyde/m3 is obtained. A health precaution guide value (RW I) of 0.1 mg acetaldehyde/m3 is recommended.

  13. Robust message routing for mobile (wireless) ad hoc networks.

    SciTech Connect

    Goldsby, Michael E.; Johnson, Michael M.; Kilman, Dominique Marie; Bierbaum, Neal Robert; Chen, Helen Y.; Ammerlahn, Heidi R.; Tsang, Rose P.; Nicol, David M.

    2004-01-01

    This report describes the results of research targeting improvements in the robustness of message transport in wireless ad hoc networks. The first section of the report provides an analysis of throughput and latency in the wireless medium access control (MAC) layer and relates the analysis to the commonly used 802.11 protocol. The second section describes enhancements made to several existing models of wireless MAC and ad hoc routing protocols; the models were used in support of the work described in the following section. The third section of the report presents a lightweight transport layer protocol that is superior to TCP for use in wireless networks. In addition, it introduces techniques that improve the performance of any ad hoc source routing protocol. The fourth section presents a novel, highly scalable ad hoc routing protocol that is based on geographic principles but requires no localization hardware.

  14. Modeling Terrain Impact on Mobile Ad Hoc Networks (MANET) Connectivity

    DTIC Science & Technology

    2014-05-01

    Modeling Terrain Impact on Mobile Ad Hoc Networks ( MANET ) Connectivity Lance Joneckis Corinne Kramer David Sparrow David Tate I N S T I T U T E F...SUBTITLE Modeling Terrain Impact on Mobile Ad Hoc Networks ( MANET ) Connectivity 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...U.S. Government pursuant to the copyright license under the clause at DFARS 252.227-7013 (a)(16) [Sep 2011]. Modeling terrain impact on MANET

  15. [Guide values for 1-butanol in indoor air. Report of the German Ad Hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and of the States' Supreme Health Authorities].

    PubMed

    2014-06-01

    The German Ad Hoc Working Group on Indoor Guidelines of the Indoor Air Hygiene Committee and the States' Supreme Health Authorities is issuing indoor air guide values to protect public health. No human studies of sufficient quality are available for the evaluation of 1-butanol in indoor air. In a well-documented oral study on reproduction toxicity in rats, assessed as reliable, impairment of embryo development was observed. Benchmark modeling of the study data by US-EPA revealed a BMDL10 of 26.1 mg/kg b.w. per day. The working group used this BMDL10 as the point of departure for the derivation of the guide value II. Considering a human respiration rate of 20 m(3) per day and a human body weight of 70 kg, this dose was converted into an inhalative concentration. Applying a factor of 0.6 to account for the inhalative absorption rate, an allometric extrapolation factor from rat to human (factor 4), an interspecies factor of 2.5 for toxicodynamics, and a factor of 10 to account for individual differences (intraspecies factor), results in a health hazard guide value (RW II) of 2 mg 1-butanol/m(3). The benchmark dose calculation of the same study generated a BMDL05 of 12.4 mg/kg b.w. per day. Applying the same assessment factors as for RW II, a precautionary guide value (RW I) of 0.7 mg 1-butanol/m(3) indoor air is calculated.

  16. What is the Problem of Ad Hoc Hypotheses?

    NASA Astrophysics Data System (ADS)

    Bamford, Greg

    The received view of an ad hochypothesis is that it accounts for only the observation(s) it was designed to account for, and so non-ad hocness is generally held to be necessary or important for an introduced hypothesis or modification to a theory. Attempts by Popper and several others to convincingly explicate this view, however, prove to be unsuccessful or of doubtful value, and familiar and firmer criteria for evaluating the hypotheses or modified theories so classified are characteristically available. These points are obscured largely because the received view fails to adequately separate psychology from methodology or to recognise ambiguities in the use of ''ad hoc_''.

  17. Innovative research of AD HOC network mobility model

    NASA Astrophysics Data System (ADS)

    Chen, Xin

    2017-08-01

    It is difficult for researchers of AD HOC network to conduct actual deployment during experimental stage as the network topology is changeable and location of nodes is unfixed. Thus simulation still remains the main research method of the network. Mobility model is an important component of AD HOC network simulation. It is used to describe the movement pattern of nodes in AD HOC network (including location and velocity, etc.) and decides the movement trail of nodes, playing as the abstraction of the movement modes of nodes. Therefore, mobility model which simulates node movement is an important foundation for simulation research. In AD HOC network research, mobility model shall reflect the movement law of nodes as truly as possible. In this paper, node generally refers to the wireless equipment people carry. The main research contents include how nodes avoid obstacles during movement process and the impacts of obstacles on the mutual relation among nodes, based on which a Node Self Avoiding Obstacle, i.e. NASO model is established in AD HOC network.

  18. Auto-configuration protocols in mobile ad hoc networks.

    PubMed

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity.

  19. How to Bootstrap Security for Ad-Hoc Network: Revisited

    NASA Astrophysics Data System (ADS)

    Shin, Wook; Gunter, Carl A.; Kiyomoto, Shinsaku; Fukushima, Kazuhide; Tanaka, Toshiaki

    There are various network-enabled and embedded computers deployed around us. Although we can get enormous conveniences by connecting them together, it is difficult to securely associate them in an ad-hoc manner. The difficulties originate from authentication and key distribution problems among devices that are strangers to each other. In this paper, we review the existing ways of initiating secure communication for ad-hoc network devices, and propose another solution. Exploiting Pairing-based cryptography and the notion of location-limited channel, the proposed solution bootstraps security conveniently and efficiently. Further, it supports ownership enforcement and key-escrow.

  20. Global Coverage from Ad-Hoc Constellations in Rideshare Orbits

    NASA Technical Reports Server (NTRS)

    Ellis, Armin; Mercury, Michael; Brown, Shannon

    2012-01-01

    A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

  1. Routing Protocol of Sparse Urban Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Li, Huxiong

    Vehicular ad hoc network (VANET) is an application of mobile ad hoc technology in transportation systems, it has become an important part of ITS. Since multi-hop link is hard to set up in sparse VANET, a traffic-aware routing (TAR) protocol is proposed which estimates vehicle average neighbors (VAN) of roads by exchanging beacon messages between encounter vehicles. Road with high VAN is preferred to be selected as part of forwarding path at intersection. Packets are forwarded to the next intersection in road in a greedy manner. Simulations show that TAR outperforms the compared protocols in terms of both packet delivery ratio and average end-to-end delay.

  2. Global Coverage from Ad-Hoc Constellations in Rideshare Orbits

    NASA Technical Reports Server (NTRS)

    Ellis, Armin; Mercury, Michael; Brown, Shannon

    2012-01-01

    A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

  3. Providing Location Security in Vehicular Ad Hoc Networks

    ERIC Educational Resources Information Center

    Yan, Gongjun

    2010-01-01

    Location is fundamental information in Vehicular Ad-hoc Networks (VANETs). Almost all VANET applications rely on location information. Therefore it is of importance to ensure location information integrity, meaning that location information is original (from the generator), correct (not bogus or fabricated) and unmodified (value not changed). We…

  4. Project "Freestyle": Ad Hoc: Fast-Turn-Around Evaluation.

    ERIC Educational Resources Information Center

    Smith, Karen

    Project "Freestyle" involved the development of prototypical television materials and a comic book intended to combat sex-role stereotyping in career-related attitudes of nine to twelve-year-old children. At various times during the early developmental stages of "Freestyle" materials, "ad hoc fast-turn-around" formative evaluations were conducted.…

  5. Providing Location Security in Vehicular Ad Hoc Networks

    ERIC Educational Resources Information Center

    Yan, Gongjun

    2010-01-01

    Location is fundamental information in Vehicular Ad-hoc Networks (VANETs). Almost all VANET applications rely on location information. Therefore it is of importance to ensure location information integrity, meaning that location information is original (from the generator), correct (not bogus or fabricated) and unmodified (value not changed). We…

  6. Adaptive Power Control MAC in Wireless Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Choi, Hong-Seok; Byun, Hee-Jung; Lim, Jong-Tae

    In this letter, we suggest APMAC (Adaptive Power Control MAC) for wireless ad hoc networks. APMAC is based on the single channel environment and improves the throughput and the energy efficiency simultaneously. Furthermore, the APMAC prevents the unfair channel starvation among the transmission pairs. We verify the performance of the APMAC through simulations.

  7. Shuttle-run synchronization in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Ma, Sheng-Fei; Bi, Hong-Jie; Zou, Yong; Liu, Zong-Hua; Guan, Shu-Guang

    2015-06-01

    In this work, we study the collective dynamics of phase oscillators in a mobile ad hoc network whose topology changes dynamically. As the network size or the communication radius of individual oscillators increases, the topology of the ad hoc network first undergoes percolation, forming a giant cluster, and then gradually achieves global connectivity. It is shown that oscillator mobility generally enhances the coherence in such networks. Interestingly, we find a new type of phase synchronization/clustering, in which the phases of the oscillators are distributed in a certain narrow range, while the instantaneous frequencies change signs frequently, leading to shuttle-run-like motion of the oscillators in phase space. We conduct a theoretical analysis to explain the mechanism of this synchronization and obtain the critical transition point.

  8. Distributed Reinforcement Learning Approach for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Wu, Celimuge; Kumekawa, Kazuya; Kato, Toshihiko

    In Vehicular Ad hoc Networks (VANETs), general purpose ad hoc routing protocols such as AODV cannot work efficiently due to the frequent changes in network topology caused by vehicle movement. This paper proposes a VANET routing protocol QLAODV (Q-Learning AODV) which suits unicast applications in high mobility scenarios. QLAODV is a distributed reinforcement learning routing protocol, which uses a Q-Learning algorithm to infer network state information and uses unicast control packets to check the path availability in a real time manner in order to allow Q-Learning to work efficiently in a highly dynamic network environment. QLAODV is favored by its dynamic route change mechanism, which makes it capable of reacting quickly to network topology changes. We present an analysis of the performance of QLAODV by simulation using different mobility models. The simulation results show that QLAODV can efficiently handle unicast applications in VANETs.

  9. Dynamic Control of Service Delivery for Ad Hoc Systems

    DTIC Science & Technology

    2006-10-01

    solutions for Localisation of mobile entities and propagation of information for routing the service in a mobile environment. Ad hoc Data Dissemination...available on the topology, the configuration of the network (SLA, user profiles, …), the localisation of the users in order to deliver the services...services. HCDR sub-networks are based on Adhoc technologies. • The enhanced civilian radio sub-networks (S- WIFI , S-WIMAX) : These technologies will

  10. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2009-08-01

    The overall performance attainable by a mobile ad hoc network depends fundamentally on the MIMO channel characteristics . During the past year the...propagation environment and an aperture within which the antennas must reside [1]. However, achieving these characteristics is difficult if not...determine the current distribution of Aperture 1 using the Covariance Method and compute the diversity gain obtained using the radiation characteristics

  11. Decentralized session initiation protocol solution in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Han, Lu; Jin, Zhigang; Shu, Yantai; Dong, Linfang

    2006-10-01

    With the fast development of ad hoc networks, SIP has attracted more and more attention in multimedia service. This paper proposes a new architecture to provide SIP service for ad hoc users, although there is no centralized SIP server deployed. In this solution, we provide the SIP service by the introduction of two nodes: Designated SIP Server (DS) and its Backup Server (BDS). The nodes of ad hoc network designate DS and BDS when they join the session nodes set and when some pre-defined events occur. A new sip message type called REGISTRAR is presented so nodes can send others REGISTRAR message to declare they want to be DS. According to the IP information taken in the message, an algorithm works like the election of DR and BDR in OSPF protocol is used to vote DS and BDS SIP servers. Naturally, the DS will be replaced by BDS when the DS is down for predicable or unpredictable reasons. To facilitate this, the DS should register to the BDS and transfer a backup of the SIP users' database. Considering the possibility DS or BDS may abruptly go down, a special policy is given. When there is no DS and BDS, a new election procedure is triggered just like the startup phase. The paper also describes how SIP works normally in the decentralized model as well as the evaluation of its performance. All sessions based on SIP in ad hoc such as DS voting have been tested in the real experiments within a 500m*500m square area where about 30 random nodes are placed.

  12. MWAHCA: a multimedia wireless ad hoc cluster architecture.

    PubMed

    Diaz, Juan R; Lloret, Jaime; Jimenez, Jose M; Sendra, Sandra

    2014-01-01

    Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal.

  13. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    PubMed Central

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  14. Auto-Configuration Protocols in Mobile Ad Hoc Networks

    PubMed Central

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity. PMID:22163814

  15. MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture

    PubMed Central

    Diaz, Juan R.; Jimenez, Jose M.; Sendra, Sandra

    2014-01-01

    Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal. PMID:24737996

  16. Developing a Conceptual Unmanned Aerial Vehicle Communications Mobile AD Hoc Network Simulation Model

    DTIC Science & Technology

    2002-06-01

    Elizabeth Royer described the Ad Hoc On-Demand Distance Vector (AODV) routing protocol as “providing quick and efficient route establishment between...Network.” Thesis, Naval Postgraduate School, December 2000. 8. Das, Samir R., Perkins, Charles E., and Royer, Elizabeth M. “ The Ad-hoc On-Demand...Lidong. “Securing Ad Hoc Networks.” Paper Cornell University, Itaca, New York, NY. 16. Corson , Scott S., and Macker, J. “Mobile Ad Hoc

  17. 75 FR 15742 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ... SPACE ADMINISTRATION NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting AGENCY... Administration announces a meeting of the Ad-Hoc Task Force on Planetary Defense of the NASA Advisory Council... include: Ad-Hoc Task Force on Planetary Defense Terms of Reference. NASA Near Earth Object (NEO)...

  18. 75 FR 43565 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... SPACE ADMINISTRATION NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting AGENCY... Administration announces a two-part meeting of the Ad-Hoc Task Force on Planetary Defense of the NASA Advisory...@nasa.gov . SUPPLEMENTARY INFORMATION: The agenda topic is: Drafting of the Ad-Hoc Task Force...

  19. Overview of the INEX 2008 Ad Hoc Track

    NASA Astrophysics Data System (ADS)

    Kamps, Jaap; Geva, Shlomo; Trotman, Andrew; Woodley, Alan; Koolen, Marijn

    This paper gives an overview of the INEX 2008 Ad Hoc Track. The main goals of the Ad Hoc Track were two-fold. The first goal was to investigate the value of the internal document structure (as provided by the XML mark-up) for retrieving relevant information. This is a continuation of INEX 2007 and, for this reason, the retrieval results are liberalized to arbitrary passages and measures were chosen to fairly compare systems retrieving elements, ranges of elements, and arbitrary passages. The second goal was to compare focused retrieval to article retrieval more directly than in earlier years. For this reason, standard document retrieval rankings have been derived from all runs, and evaluated with standard measures. In addition, a set of queries targeting Wikipedia have been derived from a proxy log, and the runs are also evaluated against the clicked Wikipedia pages. The INEX 2008 Ad Hoc Track featured three tasks: For the Focused Task a ranked-list of non-overlapping results (elements or passages) was needed. For the Relevant in Context Task non-overlapping results (elements or passages) were returned grouped by the article from which they came. For the Best in Context Task a single starting point (element start tag or passage start) for each article was needed. We discuss the results for the three tasks, and examine the relative effectiveness of element and passage retrieval. This is examined in the context of content only (CO, or Keyword) search as well as content and structure (CAS, or structured) search. Finally, we look at the ability of focused retrieval techniques to rank articles, using standard document retrieval techniques, both against the judged topics as well as against queries and clicks from a proxy log.

  20. Ubiquitous and Secure Certificate Service for Wireless Ad Hoc Network

    NASA Astrophysics Data System (ADS)

    Ge, Meng; Lam, Kwok-Yan; Li, Jianbin; Chung, Siu-Leung

    Wireless ad hoc network is one of the most suitable platforms for providing communication services to support mobile applications in public areas where no fixed communication infrastructure exists. However, due to the open nature of wireless links and lack of security infrastructure in an ad hoc network environment, applications operating on ad hoc network platforms are subjected to non-trivial security challenges. Asymmetric key management, which is widely adopted to be an effective basis for security services in an open network environment, typically plays a crucial role in meeting the security requirements of such applications. In this paper, we propose a secure asymmetric key management scheme, the Ubiquitous and Secure Certificate Service (USCS), which is based on a variant of the Distributed Certificate Authority (DCA) - the Fully Distributed Certificate Authority (FDCA). Similar to FDCA, USCS introduces the presence of 1-hop neighbors which hold shares of DCA's private signature key, and can collaborate to issue certificates, thereby providing asymmetric key management service. Both USCS and FDCA aim to achieve higher availability than the basic DCA scheme; however, USCS is more secure than FDCA in that the former achieves high availability by distributing existing shares to new members, rather than generating new shares as the FDCA scheme does. In order to realise the high availability potential of USCS, a share selection algorithm is also proposed. Experimental results demonstrated that USCS is a more secure approach of the DCA scheme in that it can achieve stronger security than FDCA while attaining high availability similar to that of FDCA. Experiments also showed that USCS incurs only moderate communication overheads.

  1. Stochastic does not equal ad hoc. [theories of lunar origin

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1984-01-01

    Some classes of influential events in solar system history are class-predictable but not event-predictable. Theories of lunar origin should not ignore class-predictable stochastic events. Impacts and close encounters with large objects during planet formation are class-predictable. These stochastic events, such as large impacts that triggered ejection of Earth-mantle material into a circum-Earth cloud, should not be rejected as ad hoc. A way to deal with such events scientifically is to investigate their consequences; if it can be shown that they might produce the Moon, they become viable concepts in theories of lunar origin.

  2. Scalable Architecture for Multihop Wireless ad Hoc Networks

    NASA Technical Reports Server (NTRS)

    Arabshahi, Payman; Gray, Andrew; Okino, Clayton; Yan, Tsun-Yee

    2004-01-01

    A scalable architecture for wireless digital data and voice communications via ad hoc networks has been proposed. Although the details of the architecture and of its implementation in hardware and software have yet to be developed, the broad outlines of the architecture are fairly clear: This architecture departs from current commercial wireless communication architectures, which are characterized by low effective bandwidth per user and are not well suited to low-cost, rapid scaling in large metropolitan areas. This architecture is inspired by a vision more akin to that of more than two dozen noncommercial community wireless networking organizations established by volunteers in North America and several European countries.

  3. Ad Hoc Selection of Voice over Internet Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell G. (Inventor); Bullock, John T. (Inventor)

    2008-01-01

    A method and apparatus for a communication system technique involving ad hoc selection of at least two audio streams is provided. Each of the at least two audio streams is a packetized version of an audio source. A data connection exists between a server and a client where a transport protocol actively propagates the at least two audio streams from the server to the client. Furthermore, software instructions executable on the client indicate a presence of the at least two audio streams, allow selection of at least one of the at least two audio streams, and direct the selected at least one of the at least two audio streams for audio playback.

  4. Ad Hoc Selection of Voice over Internet Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell G. (Inventor); Bullock, John T. (Inventor)

    2014-01-01

    A method and apparatus for a communication system technique involving ad hoc selection of at least two audio streams is provided. Each of the at least two audio streams is a packetized version of an audio source. A data connection exists between a server and a client where a transport protocol actively propagates the at least two audio streams from the server to the client. Furthermore, software instructions executable on the client indicate a presence of the at least two audio streams, allow selection of at least one of the at least two audio streams, and direct the selected at least one of the at least two audio streams for audio playback.

  5. Approximate ad-hoc query engine for simulation data

    SciTech Connect

    Abdulla, G; Baldwin, C; Critchlow, T; Kamimura, R; Lozares, I; Musick, R; Tang, N; Lee, B S; Snapp, R

    2001-02-01

    In this paper, we describe AQSim, an ongoing effort to design and implement a system to manage terabytes of scientific simulation data. The goal of this project is to reduce data storage requirements and access times while permitting ad-hoc queries using statistical and mathematical models of the data. In order to facilitate data exchange between models based on different representations, we are evaluating using the ASCI common data model which is comprised of several layers of increasing semantic complexity. To support queries over the spatial-temporal mesh structured data we are in the process of defining and implementing a grammar for MeshSQL.

  6. Clinical teacher training--maximising the 'ad hoc' teaching encounter.

    PubMed

    Molodysky, Eugen

    2007-12-01

    Classically, the patient is absent when the learner makes an 'ad hoc' corridor enquiry of their supervisor. This teaching encounter challenges the supervisor to ensure that the educational benefit is not limited by the brevity of the encounter. Focusing on some of the critical steps or teaching skills involved in the learning process increases the efficiency and effectiveness of this type of teaching encounter. Educationalists have provided models to optimise this fleeting corridor enquiry. This article presents a range of scripted clinical teaching scenarios that demonstrate the sound educational theory and principles underlying one such model--the 'one minute preceptor' or 'five step microskills model' of clinical teaching.

  7. Ground-based observations and AD HOC models

    NASA Astrophysics Data System (ADS)

    Ground based observations of B stars in the visible, the infrared, and the radio region are described along with the ad hoc models proposed to interpret them. It is shown that these observations refer essentially to the photosphere and to the regions of the outer atmosphere where the gas is cool and at low velocity. The characteristics of the variability of the continuous and line spectrum are examined in general and in the cases of individual stars. Finally, linear polarization in the B stars is discussed.

  8. Energy Efficient Probabilistic Broadcasting for Mobile Ad-Hoc Network

    NASA Astrophysics Data System (ADS)

    Kumar, Sumit; Mehfuz, Shabana

    2017-06-01

    In mobile ad-hoc network (MANETs) flooding method is used for broadcasting route request (RREQ) packet from one node to another node for route discovery. This is the simplest method of broadcasting of RREQ packets but it often results in broadcast storm problem, originating collisions and congestion of packets in the network. A probabilistic broadcasting is one of the widely used broadcasting scheme for route discovery in MANETs and provides solution for broadcasting storm problem. But it does not consider limited energy of the battery of the nodes. In this paper, a new energy efficient probabilistic broadcasting (EEPB) is proposed in which probability of broadcasting RREQs is calculated with respect to remaining energy of nodes. The analysis of simulation results clearly indicate that an EEPB route discovery scheme in ad-hoc on demand distance vector (AODV) can increase the network lifetime with a decrease in the average power consumption and RREQ packet overhead. It also decreases the number of dropped packets in the network, in comparison to other EEPB schemes like energy constraint gossip (ECG), energy aware gossip (EAG), energy based gossip (EBG) and network lifetime through energy efficient broadcast gossip (NEBG).

  9. Energy Efficient Probabilistic Broadcasting for Mobile Ad-Hoc Network

    NASA Astrophysics Data System (ADS)

    Kumar, Sumit; Mehfuz, Shabana

    2016-08-01

    In mobile ad-hoc network (MANETs) flooding method is used for broadcasting route request (RREQ) packet from one node to another node for route discovery. This is the simplest method of broadcasting of RREQ packets but it often results in broadcast storm problem, originating collisions and congestion of packets in the network. A probabilistic broadcasting is one of the widely used broadcasting scheme for route discovery in MANETs and provides solution for broadcasting storm problem. But it does not consider limited energy of the battery of the nodes. In this paper, a new energy efficient probabilistic broadcasting (EEPB) is proposed in which probability of broadcasting RREQs is calculated with respect to remaining energy of nodes. The analysis of simulation results clearly indicate that an EEPB route discovery scheme in ad-hoc on demand distance vector (AODV) can increase the network lifetime with a decrease in the average power consumption and RREQ packet overhead. It also decreases the number of dropped packets in the network, in comparison to other EEPB schemes like energy constraint gossip (ECG), energy aware gossip (EAG), energy based gossip (EBG) and network lifetime through energy efficient broadcast gossip (NEBG).

  10. Adaptive link-layer intelligence for enhanced ad hoc networking

    NASA Astrophysics Data System (ADS)

    MacLennan, James; Walburg, Bill; Nevins, Larry; Hartup, David

    2005-05-01

    Networked radio systems that utilize self-forming, fault tolerant techniques offer needed communication functions for Homeland Security and Law Enforcement agencies. The use of an ad hoc mesh network architecture solves some of the problems inherent to the wireless physical layer such as interferers, multi-path fading, shadowing, and loss of line-of-site. These effects severely limit the performance of current 802.11 wireless network implementations. This paper describes the use of Adaptive Link-layer Intelligence for Enhanced ad hoc Networking. This technology enhances recognition and characterization of sources of wireless channel perturbations and predicts their effects on wireless link quality. Identifying and predicting channel problems at the link level improves dynamic route discovery, circumvents channel disruptions before they cause a link failure, and increases communications reliability and data rate. First Responders, Homeland Security, and Law Enforcement agencies operating in locations lacking infrastructure, such as Urban Search and Rescue (USAR) operations, can benefit from increased communications reliability in highly impaired channels that are typical in disaster response scenarios.

  11. Decentralized Time Geography for Ad-Hoc Collaborative Planning

    NASA Astrophysics Data System (ADS)

    Raubal, Martin; Winter, Stephan; Dorr, Christopher

    For an autonomous physical agent, such as a moving robot or a person with their mobile device, performing a task in a spatio-temporal environment often requires interaction with other agents. In this paper we study ad-hoc collaborative planning between these autonomous peers. We introduce the notion of decentralized time geography, which differs from the traditional time-geographic framework by taking into account limited local knowledge. This allows agents to perform a space-time analysis within a time-geographic framework that represents local knowledge in a distributed environment as required for ad-hoc coordinated action between agents in physical space. More specifically, we investigate the impact of general agent movement, replacement seeking, and location and goal-directed behavior of the initiating agent on the outcome of the collaborative planning. Empirical tests in a multi-agent simulation framework provide both a proof of concept and specific results for different combinations of agent density and communication radius.

  12. Intelligent routing protocol for ad hoc wireless network

    NASA Astrophysics Data System (ADS)

    Peng, Chaorong; Chen, Chang Wen

    2006-05-01

    A novel routing scheme for mobile ad hoc networks (MANETs), which combines hybrid and multi-inter-routing path properties with a distributed topology discovery route mechanism using control agents is proposed in this paper. In recent years, a variety of hybrid routing protocols for Mobile Ad hoc wireless networks (MANETs) have been developed. Which is proactively maintains routing information for a local neighborhood, while reactively acquiring routes to destinations beyond the global. The hybrid protocol reduces routing discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the other side the hybrid routing protocols in MANETs likes Zone Routing Protocol still need route "re-discover" time when a route between zones link break. Sine the topology update information needs to be broadcast routing request on local zone. Due to this delay, the routing protocol may not be applicable for real-time data and multimedia communication. We utilize the advantages of a clustering organization and multi-routing path in routing protocol to achieve several goals at the same time. Firstly, IRP efficiently saves network bandwidth and reduces route reconstruction time when a routing path fails. The IRP protocol does not require global periodic routing advertisements, local control agents will automatically monitor and repair broke links. Secondly, it efficiently reduces congestion and traffic "bottlenecks" for ClusterHeads in clustering network. Thirdly, it reduces significant overheads associated with maintaining clusters. Fourthly, it improves clusters stability due to dynamic topology changing frequently. In this paper, we present the Intelligent Routing Protocol. First, we discuss the problem of routing in ad hoc networks and the motivation of IRP. We describe the hierarchical architecture of IRP. We describe the routing process and illustrate it with an example. Further, we describe the control manage

  13. Opportunistic Channel Scheduling for Ad Hoc Networks with Queue Stability

    NASA Astrophysics Data System (ADS)

    Dong, Lei; Wang, Yongchao

    2015-03-01

    In this paper, a distributed opportunistic channel access strategy in ad hoc network is proposed. We consider the multiple sources contend for the transmission opportunity, the winner source decides to transmit or restart contention based on the current channel condition. Owing to real data assumption at all links, the decision still needs to consider the stability of the queues. We formulate the channel opportunistic scheduling as a constrained optimization problem which maximizes the system average throughput with the constraints that the queues of all links are stable. The proposed optimization model is solved by Lyapunov stability in queueing theory. The successive channel access problem is decoupled into single optimal stopping problem at every frame and solved with Lyapunov algorithm. The threshold for every frame is different, and it is derived based on the instantaneous queue information. Finally, computer simulations are conducted to demonstrate the validity of the proposed strategy.

  14. Undilatable Stent Neoatherosclerosis Treated with Ad Hoc Rotational Atherectomy

    PubMed Central

    Koutouzis, Michael; Maniotis, Christos; Tsiafoutis, Ioannis; Argyriou, Mihalis

    2017-01-01

    A middle age woman with known ischemic heart disease and old stents in proximal left anterior descending coronary artery (LAD) was admitted to Coronary Care Unit with acute coronary syndrome. The coronary angiography showed one vessel disease with significant restenosis within the previously implanted stents. The lesion was tough and remained undilatable despite high pressure balloon inflation. Eventually, the balloon ruptured creating a massive dissection of the LAD beginning immediately after the distal part of the undilatable lesion. We proceeded with a challenging ad hoc rotational atherectomy of the lesion and finally stenting of the lesion. In-stent restenosis many years after stent implantation is considered to be mainly due to neoatheromatosis compared to intimal hyperplasia, making lesion treatment more difficult and unpredictable. PMID:28168062

  15. Topology for efficient information dissemination in ad-hoc networking

    NASA Technical Reports Server (NTRS)

    Jennings, E.; Okino, C. M.

    2002-01-01

    In this paper, we explore the information dissemination problem in ad-hoc wirless networks. First, we analyze the probability of successful broadcast, assuming: the nodes are uniformly distributed, the available area has a lower bould relative to the total number of nodes, and there is zero knowledge of the overall topology of the network. By showing that the probability of such events is small, we are motivated to extract good graph topologies to minimize the overall transmissions. Three algorithms are used to generate topologies of the network with guaranteed connectivity. These are the minimum radius graph, the relative neighborhood graph and the minimum spanning tree. Our simulation shows that the relative neighborhood graph has certain good graph properties, which makes it suitable for efficient information dissemination.

  16. Realistic Mobility Modeling for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Akay, Hilal; Tugcu, Tuna

    2009-08-01

    Simulations used for evaluating the performance of routing protocols for Vehicular Ad Hoc Networks (VANET) are mostly based on random mobility and fail to consider individual behaviors of the vehicles. Unrealistic assumptions about mobility produce misleading results about the behavior of routing protocols in real deployments. In this paper, a realistic mobility modeling tool, Mobility for Vehicles (MOVE), which considers the basic mobility behaviors of vehicles, is proposed for a more accurate evaluation. The proposed model is tested against the Random Waypoint (RWP) model using AODV and OLSR protocols. The results show that the mobility model significantly affects the number of nodes within the transmission range of a node, the volume of control traffic, and the number of collisions. It is shown that number of intersections, grid size, and node density are important parameters when dealing with VANET performance.

  17. Topology for efficient information dissemination in ad-hoc networking

    NASA Technical Reports Server (NTRS)

    Jennings, E.; Okino, C. M.

    2002-01-01

    In this paper, we explore the information dissemination problem in ad-hoc wirless networks. First, we analyze the probability of successful broadcast, assuming: the nodes are uniformly distributed, the available area has a lower bould relative to the total number of nodes, and there is zero knowledge of the overall topology of the network. By showing that the probability of such events is small, we are motivated to extract good graph topologies to minimize the overall transmissions. Three algorithms are used to generate topologies of the network with guaranteed connectivity. These are the minimum radius graph, the relative neighborhood graph and the minimum spanning tree. Our simulation shows that the relative neighborhood graph has certain good graph properties, which makes it suitable for efficient information dissemination.

  18. Remote Upload of Evidence over Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Ray, Indrajit

    In this work, we report on one aspect of an autonomous robot-based digital evidence acquisition system that we are developing. When forensic investigators operate within a hostile environment they may use remotely operated unmanned devices to gather digital evidence. These systems periodically upload the evidence to a remote central server using a mobile ad hoc network. In such cases, large pieces of information need to be fragmented and transmitted in an appropriate manner. To support proper forensic analysis, certain properties must ensured for each fragment of evidence — confidentiality during communication, authenticity and integrity of the data, and, most importantly, strong evidence of membership for fragments. This paper describes a framework to provide these properties for the robot-based evidence acquisition system under development.

  19. Extending Service Area of IEEE 802.11 Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Choi, Woo-Yong

    2012-06-01

    According to the current IEEE 802.11 wireless LAN standards, IEEE 802.11 ad hoc networks have the limitation that all STAs (Stations) are in the one-hop transmission range of each other. In this paper, to alleviate the limitation of IEEE 802.11 ad hoc networks we propose the efficient method for selecting the most appropriate pseudo AP (Access Point) from among the set of ad hoc STAs and extending the service area of IEEE 802.11 ad hoc networks by the pseudo AP's relaying the internal traffic of IEEE 802.11 ad hoc networks. Numerical examples show that the proposed method significantly extends the service area of IEEE 802.11 ad hoc networks.

  20. An Analysis Platform for Mobile Ad Hoc Network (MANET) Scenario Execution Log Data

    DTIC Science & Technology

    2016-01-01

    ARL-TR-7574 ● JAN 2016 US Army Research Laboratory An Analysis Platform for Mobile Ad Hoc Network (MANET) Scenario Execution Log...Analysis Platform for Mobile Ad Hoc Network (MANET) Scenario Execution Log Data by Jaime C Acosta and Yadira Jacquez Survivability/Lethality Analysis...August 2015 4. TITLE AND SUBTITLE An Analysis Platform for Mobile Ad Hoc Network (MANET) Scenario Execution Log Data 5a. CONTRACT NUMBER 5b. GRANT

  1. Trust recovery model of Ad Hoc network based on identity authentication scheme

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Huan, Shuiyuan

    2017-05-01

    Mobile Ad Hoc network trust model is widely used to solve mobile Ad Hoc network security issues. Aiming at the problem of reducing the network availability caused by the processing of malicious nodes and selfish nodes in mobile Ad Hoc network routing based on trust model, an authentication mechanism based on identity authentication mobile Ad Hoc network is proposed, which uses identity authentication to identify malicious nodes, And trust the recovery of selfish nodes in order to achieve the purpose of reducing network congestion and improving network quality. The simulation results show that the implementation of the mechanism can effectively improve the network availability and security.

  2. Journey from Mobile Ad Hoc Networks to Wireless Mesh Networks

    NASA Astrophysics Data System (ADS)

    Wang, Junfang; Xie, Bin; Agrawal, Dharma P.

    A wireless mesh network (WMN) is a particular type of mobile ad hoc network (MANET), which aims to provide ubiquitous high bandwidth access for a large number of users. A pure MANET is dynamically formed by mobile devices without the requirement of any existing infrastructure or prior network configuration. Similar to MANETs, a WMN also has the ability of self-organization, self-discovering, self-healing, and self-configuration. However, a WMN is typically a collection of stationary mesh routers (MRs) with each employing multiple radios. Some MRs have wired connections and act as the Internet gateways (IGWs) to provide Internet connectivity for other MRs. These new features of WMNs over MANETs enable them to be a promising alternative for high broadband Internet access. In this chapter, we elaborate on the evolution from MANETs to WMNs and provide a comprehensive understanding of WMNs from theoretical aspects to practical protocols, while comparing it with MANETs. In particular, we focus on the following critical issues with respect to WMN deployment: Network Capacity, Positioning Technique, Fairness Transmission and Multiradio Routing Protocols. We end this chapter with some open problems and future directions in WMNs.

  3. Algorithmic aspects of topology control problems for ad hoc networks

    SciTech Connect

    Liu, R.; Lloyd, E. L.; Marathe, M. V.; Ramanathan, R.; Ravi, S. S.

    2002-01-01

    Topology control problems are concerned with the assignment of power values to nodes of an ad hoc network so that the power assignment leads to a graph topology satisfying some specified properties. This paper considers such problems under several optimization objectives, including minimizing the maximum power and minimizing the total power. A general approach leading to a polynomial algorithm is presented for minimizing maximum power for a class of graph properties, called monotone properties. The difficulty of generalizing the approach to properties that are not monoione is pointed out. Problems involving the minimization of total power are known to be NP-complete even for simple graph properties. A general approach that leads to an approximation algorithm for minimizing the total power for some monotone properties is presented. Using this approach, a new approximation algorithm for the problem of minimizing the total power for obtaining a 2-node-connected graph is obtained. It is shown that this algorithm provides a constant performance guarantee. Experimental results from an implementation of the approximation algorithm are also presented.

  4. Detecting and isolating malicious nodes in wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Li, Fanzhi; Jassim, Sabah

    2007-04-01

    Malicious nodes can seriously impair the performance of wireless ad hoc networks as a result of different actions such as packet dropping. Secure routes are shortest paths on which every node on the route is trusted even if unknown. Secure route discovery requires the adoption of mechanisms of associating trust to nodes. Most existing secure route discovery mechanisms rely on shared keys and digital signature. In the absence of central nodes that act as certification authority, such protocols suffer from heavy computational burden and are vulnerable to malicious attacks. In this paper we shall review existing techniques for secure routing and propose to complement route finding with creditability scores. Each node would have a credit list for its neighbors. Each node monitors its neighbors' pattern of delivering packets and regularly credits are reviewed and updated accordingly. Unlike most existing schemes the focus of our work is based on post route discovery stage, i.e. when packets are transmitted on discovered routes. The level of trust in any route will be based on the credits associated with the neighbors belonging to the discovered route. We shall evaluate the performance of the proposed scheme by modifying our simulation system so that each node has a dynamic changing "credit list" for its neighbors' behavior. We shall conduct a series of simulations with and without the proposed scheme and compare the results. We will demonstrate that the proposed mechanism is capable of isolating malicious nodes and thereby counteracting black hole attacks.

  5. Data management issues in mobile ad hoc networks

    PubMed Central

    HARA, Takahiro

    2017-01-01

    Research on mobile ad hoc networks (MANETs) has become a hot research topic since the middle 1990’s. Over the first decade, most research focused on networking techniques, ignoring data management issues. We, however, realized early the importance of data management in MANETs, and have been conducting studies in this area for 15 years. In this review, we summarize some key technical issues related to data management in MANETs, and the studies we have done in addressing these issues, which include placement of data replicas, update management, and query processing with security management. The techniques proposed in our studies have been designed with deep considerations of MANET features including network partitioning, node participation/disappearance, limited network bandwidth, and energy efficiency. Our studies published in early 2000’s have developed a new research field as data management in MANETs. Also, our recent studies are expected to be significant guidelines of new research directions. We conclude the review by discussing some future directions for research. PMID:28496052

  6. Data management issues in mobile ad hoc networks.

    PubMed

    Hara, Takahiro

    2017-01-01

    Research on mobile ad hoc networks (MANETs) has become a hot research topic since the middle 1990's. Over the first decade, most research focused on networking techniques, ignoring data management issues. We, however, realized early the importance of data management in MANETs, and have been conducting studies in this area for 15 years. In this review, we summarize some key technical issues related to data management in MANETs, and the studies we have done in addressing these issues, which include placement of data replicas, update management, and query processing with security management. The techniques proposed in our studies have been designed with deep considerations of MANET features including network partitioning, node participation/disappearance, limited network bandwidth, and energy efficiency. Our studies published in early 2000's have developed a new research field as data management in MANETs. Also, our recent studies are expected to be significant guidelines of new research directions. We conclude the review by discussing some future directions for research.

  7. Performance Improvement in Geographic Routing for Vehicular Ad Hoc Networks

    PubMed Central

    Kaiwartya, Omprakash; Kumar, Sushil; Lobiyal, D. K.; Abdullah, Abdul Hanan; Hassan, Ahmed Nazar

    2014-01-01

    Geographic routing is one of the most investigated themes by researchers for reliable and efficient dissemination of information in Vehicular Ad Hoc Networks (VANETs). Recently, different Geographic Distance Routing (GEDIR) protocols have been suggested in the literature. These protocols focus on reducing the forwarding region towards destination to select the Next Hop Vehicles (NHV). Most of these protocols suffer from the problem of elevated one-hop link disconnection, high end-to-end delay and low throughput even at normal vehicle speed in high vehicle density environment. This paper proposes a Geographic Distance Routing protocol based on Segment vehicle, Link quality and Degree of connectivity (SLD-GEDIR). The protocol selects a reliable NHV using the criteria segment vehicles, one-hop link quality and degree of connectivity. The proposed protocol has been simulated in NS-2 and its performance has been compared with the state-of-the-art protocols: P-GEDIR, J-GEDIR and V-GEDIR. The empirical results clearly reveal that SLD-GEDIR has lower link disconnection and end-to-end delay, and higher throughput as compared to the state-of-the-art protocols. It should be noted that the performance of the proposed protocol is preserved irrespective of vehicle density and speed. PMID:25429415

  8. Ad-Hoc Queries over Document Collections - A Case Study

    NASA Astrophysics Data System (ADS)

    Löser, Alexander; Lutter, Steffen; Düssel, Patrick; Markl, Volker

    We discuss the novel problem of supporting analytical business intelligence queries over web-based textual content, e.g., BI-style reports based on 100.000's of documents from an ad-hoc web search result. Neither conventional search engines nor conventional Business Intelligence and ETL tools address this problem, which lies at the intersection of their capabilities. "Google Squared" or our system GOOLAP.info, are examples of these kinds of systems. They execute information extraction methods over one or several document collections at query time and integrate extracted records into a common view or tabular structure. Frequent extraction and object resolution failures cause incomplete records which could not be joined into a record answering the query. Our focus is the identification of join-reordering heuristics maximizing the size of complete records answering a structured query. With respect to given costs for document extraction we propose two novel join-operations: The multi-way CJ-operator joins records from multiple relationships extracted from a single document. The two-way join-operator DJ ensures data density by removing incomplete records from results. In a preliminary case study we observe that our join-reordering heuristics positively impact result size, record density and lower execution costs.

  9. Random Time Identity Based Firewall In Mobile Ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Suman, Patel, R. B.; Singh, Parvinder

    2010-11-01

    A mobile ad hoc network (MANET) is a self-organizing network of mobile routers and associated hosts connected by wireless links. MANETs are highly flexible and adaptable but at the same time are highly prone to security risks due to the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized control. Firewall is an effective means of protecting a local network from network-based security threats and forms a key component in MANET security architecture. This paper presents a review of firewall implementation techniques in MANETs and their relative merits and demerits. A new approach is proposed to select MANET nodes at random for firewall implementation. This approach randomly select a new node as firewall after fixed time and based on critical value of certain parameters like power backup. This approach effectively balances power and resource utilization of entire MANET because responsibility of implementing firewall is equally shared among all the nodes. At the same time it ensures improved security for MANETs from outside attacks as intruder will not be able to find out the entry point in MANET due to the random selection of nodes for firewall implementation.

  10. Preferential survival in models of complex ad hoc networks

    NASA Astrophysics Data System (ADS)

    Kong, Joseph S.; Roychowdhury, Vwani P.

    2008-05-01

    There has been a rich interplay in recent years between (i) empirical investigations of real-world dynamic networks, (ii) analytical modeling of the microscopic mechanisms that drive the emergence of such networks, and (iii) harnessing of these mechanisms to either manipulate existing networks, or engineer new networks for specific tasks. We continue in this vein, and study the deletion phenomenon in the web by the following two different sets of websites (each comprising more than 150,000 pages) over a one-year period. Empirical data show that there is a significant deletion component in the underlying web networks, but the deletion process is not uniform. This motivates us to introduce a new mechanism of preferential survival (PS), where nodes are removed according to the degree-dependent deletion kernel, D(k)∝k, with α≥0. We use the mean-field rate equation approach to study a general dynamic model driven by Preferential Attachment (PA), Double PA (DPA), and a tunable PS (i.e., with any α>0), where c nodes ( c<1) are deleted per node added to the network, and verify our predictions via large-scale simulations. One of our results shows that, unlike in the case of uniform deletion (i.e., where α=0), the PS kernel when coupled with the standard PA mechanism, can lead to heavy-tailed power-law networks even in the presence of extreme turnover in the network. Moreover, a weak DPA mechanism, coupled with PS, can help to make the network even more heavy-tailed, especially in the limit when deletion and insertion rates are almost equal, and the overall network growth is minimal. The dynamics reported in this work can be used to design and engineer stable ad hoc networks and explain the stability of the power-law exponents observed in real-world networks.

  11. A Token Ring Protocol for Dynamic Ad-hoc Wireless Environments

    SciTech Connect

    Top, P; Kohlhepp, V; Dowla, F

    2005-09-30

    A wireless ad-hoc networking protocol is presented. The protocol is designed to be flexible, easy to use and adaptable to a wide variety of potential applications. The primary considerations in design are small code size, guaranteed bandwidth access, limited delay, and error resilience in a highly dynamic ad-hoc environment. These considerations are achieved through the use of token ring protocol.

  12. Typicality Mediates Performance during Category Verification in Both Ad-Hoc and Well-Defined Categories

    ERIC Educational Resources Information Center

    Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

    2012-01-01

    Background: The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this…

  13. Typicality Mediates Performance during Category Verification in Both Ad-Hoc and Well-Defined Categories

    ERIC Educational Resources Information Center

    Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

    2012-01-01

    Background: The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this…

  14. On mobile wireless ad hoc IP video transports

    NASA Astrophysics Data System (ADS)

    Kazantzidis, Matheos

    2006-05-01

    Multimedia transports in wireless, ad-hoc, multi-hop or mobile networks must be capable of obtaining information about the network and adaptively tune sending and encoding parameters to the network response. Obtaining meaningful metrics to guide a stable congestion control mechanism in the transport (i.e. passive, simple, end-to-end and network technology independent) is a complex problem. Equally difficult is obtaining a reliable QoS metrics that agrees with user perception in a client/server or distributed environment. Existing metrics, objective or subjective, are commonly used after or before to test or report on a transmission and require access to both original and transmitted frames. In this paper, we propose that an efficient and successful video delivery and the optimization of overall network QoS requires innovation in a) a direct measurement of available and bottleneck capacity for its congestion control and b) a meaningful subjective QoS metric that is dynamically reported to video sender. Once these are in place, a binomial -stable, fair and TCP friendly- algorithm can be used to determine the sending rate and other packet video parameters. An adaptive mpeg codec can then continually test and fit its parameters and temporal-spatial data-error control balance using the perceived QoS dynamic feedback. We suggest a new measurement based on a packet dispersion technique that is independent of underlying network mechanisms. We then present a binomial control based on direct measurements. We implement a QoS metric that is known to agree with user perception (MPQM) in a client/server, distributed environment by using predetermined table lookups and characterization of video content.

  15. Report of the Ad Hoc Committee on the Potential Benefits to U.S. Industry from the SDI/IST (Strategic Defense Initiative/Innovative Science and Technology) Scientific Program.

    DTIC Science & Technology

    1985-11-01

    Memorandum Report has been reviewed by the committee members listed on page ix. v.- pJ. ?. S- • iii ABSTRACT Issues and procedures that the SDI/IST...programs and activities. v 4. • m - *.***-"* -,,. ’. "*. -~--<~ " : : - CONTENTS Preface iii 5,. Abstract v List of Participants ix I. Introduction 1...II. Identification of Likely Technological Fallout from the Program of the SDI/IST Directorate 3 III . Issues and Procedures 9 Appendices--Edited

  16. Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

    PubMed Central

    Truffa, Márcio A. M.; Alves, Gustavo M.P.; Bernardi, Fernando; Esteves Filho, Antonio; Ribeiro, Expedito; Galon, Micheli Z.; Spadaro, André; Kajita, Luiz J.; Arrieta, Raul; Lemos, Pedro A.

    2015-01-01

    Background Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention. Objective To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedure Methods The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated. Results A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm2, while the staged group, to 139.2 ± 75.3 Gycm2 (p < 0.001). Conclusion Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times. PMID:26351982

  17. Resource Allocation in MIMO-Based Ad Hoc Networks

    DTIC Science & Technology

    2011-03-01

    Multiple - Input Multiple - Output ( MIMO ...Hoc Networks Peng Wang∗, John Matyjas† and Michael Medley† †Air Force Research Lab, Rome, NY Abstract— Multiple - Input Multiple - Output ( MIMO ) commu... input multiple - output systems, capacity optimization, joint routing, scheduling and power control. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION

  18. A group based key sharing and management algorithm for vehicular ad hoc networks.

    PubMed

    Khan, Zeeshan Shafi; Moharram, Mohammed Morsi; Alaraj, Abdullah; Azam, Farzana

    2014-01-01

    Vehicular ad hoc networks (VANETs) are one special type of ad hoc networks that involves vehicles on roads. Typically like ad hoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange of useless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamic topology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems on privacy, disturbance, and resource utilization. In this paper, we propose media mixing algorithm to decide what information should be provided to each user and how to provide such information. Results obtained through simulation show that fewer number of keys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach.

  19. A Group Based Key Sharing and Management Algorithm for Vehicular Ad Hoc Networks

    PubMed Central

    Moharram, Mohammed Morsi; Azam, Farzana

    2014-01-01

    Vehicular ad hoc networks (VANETs) are one special type of ad hoc networks that involves vehicles on roads. Typically like ad hoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange of useless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamic topology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems on privacy, disturbance, and resource utilization. In this paper, we propose media mixing algorithm to decide what information should be provided to each user and how to provide such information. Results obtained through simulation show that fewer number of keys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach. PMID:24587749

  20. Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

    NASA Astrophysics Data System (ADS)

    Xu, Changchun; Xu, Yanyi; Liu, Gan; Liu, Kezhong

    Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

  1. A Joint Performance-Vulnerability Metric Framework for Designing Ad Hoc Routing Protocols

    DTIC Science & Technology

    2010-11-01

    network is deployed in a hostile envi- ronment, different paths between nodes may provide varying levels of resilience to adversarial attack . Therefore, in...efficient and resilient to attack . We give an example that measures resilience to key exposure in ad hoc networks and demonstrate the feasibility of our...include Optimal Link-State Routing ( OLSR ), Dynamic Source Routing (DSR), and Ad hoc On-demand Distance Vector (AODV) routing. A survey of current

  2. Ad-Hoc Sensor Networks for Maritime Interdiction Operations and Regional Security

    DTIC Science & Technology

    2012-09-01

    to examine how unstructured sensor networks, known also as ad-hoc sensor networks, can effectively support maritime interdiction operations and...thesis is to examine how unstructured sensor networks, known also as ad-hoc sensor networks, can effectively support maritime interdiction operations...Electromagnetic EIRP Effective Isotropic Radiated Power EO Electro –Optical FOI Swedish Defense Research Agency GGB Golden Gate Bridge GPRS General Packet

  3. Improving English and Chinese Ad-hoc Retrieval: Tipster Text Phase 3

    DTIC Science & Technology

    1998-10-01

    IMPROVING ENGLISH AND CHINESE AD-HOC RETRIEVAL: TIPSTER TEXT PHASE 3 FINAL REPORT Kui-Lam Kwok Computer Science Department, Queens College, CUNY...all past TREC experiments with consistently superior results. Since 1996, we have also participated in the TIPSTER Text Phase 3 program. This...COVERED 00-00-1998 to 00-00-1998 4. TITLE AND SUBTITLE Improving English and Chinese Ad-hoc Retrieval: TIPSTER Text Phase 3 Final Report 5a

  4. Interference Drop Scheme: Enhancing QoS Provision in Multi-Hop Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Luo, Chang-Yi; Komuro, Nobuyoshi; Takahashi, Kiyoshi; Kasai, Hiroyuki; Ueda, Hiromi; Tsuboi, Toshinori

    Ad hoc networking uses wireless technologies to construct networks with no physical infrastructure and so are expected to provide instant networking in areas such as disaster recovery sites and inter-vehicle communication. Unlike conventional wired networks services, services in ad hoc networks are easily disrupted by the frequent changes in traffic and topology. Therefore, solutions to assure the Quality of Services (QoS) in ad hoc networks are different from the conventional ones used in wired networks. In this paper, we propose a new queue management scheme, Interference Drop Scheme (IDS) for ad hoc networks. In the conventional queue management approaches such as FIFO (First-in First-out) and RED (Random Early Detection), a queue is usually managed by a queue length limit. FIFO discards packets according to the queue limit, and RED discards packets in an early and random fashion. IDS, on the other hand, manages the queue according to wireless interference time, which increases as the number of contentions in the MAC layer increases. When there are many MAC contentions, IDS discards TCP data packets. By observing the interference time and discarding TCP data packets, our simulation results show that IDS improves TCP performance and reduces QoS violations in UDP in ad hoc networks with chain, grid, and random topologies. Our simulation results also demonstrate that wireless interference time is a better metric than queue length limit for queue management in multi-hop ad hoc networks.

  5. Design of multilevel heterogeneous ad-hoc wireless networks with UAVs

    NASA Astrophysics Data System (ADS)

    Gu, Daniel L.; Gerla, Mario; Ly, Henry; Xu, Kaixin; Kong, Jiejun; Hong, Xiaoyan

    2001-10-01

    Multi-Layer Ad Hoc Wireless Networks with UAVs is an ideal infrastructure to establish a rapidly deployable wireless communication system any time any where in the world for military applications. In this paper, we review the research we have done so far for our heterogeneous solution. First of all, we proposed the infrastructure of Multi-level Heterogeneous Ad-Hoc Wireless Network with UAVs. Second, we developed a new MAC layer protocol, Centralized Intelligent Channel Assigned Multiple Access (C-ICAMA), for ground mobile backbone nodes to access UAV. Third, we extended HSR (Hierarchical State Routing) to this Multi-Level Heterogeneous Ad-Hoc Wireless Network. Due to the intrinsic limitations of Extended HSR, we extended the Landmark Ad Hoc Routing (LANMAR) as our forth step. Security is a critical issue for mobile ad-hoc wireless networks, especially for military applications. We developed an embedded distributed security protocol and integrated with this heterogeneous hierarchical ad hoc wireless networks in our fifth step. Therefore, the hierarchical multi-layer approach is the most desirable approach to achieve routing scalability in multi-hop wireless networks.

  6. Ad hoc percutaneous coronary intervention: a consensus statement from the Society for Cardiovascular Angiography and Interventions.

    PubMed

    Blankenship, James C; Gigliotti, Osvaldo S; Feldman, Dmitriy N; Mixon, Timothy A; Patel, Rajan A G; Sorajja, Paul; Yakubov, Steven J; Chambers, Charles E

    2013-04-01

    Percutaneous coronary interventions (PCI) may be performed during the same session as diagnostic catheterization (ad hoc PCI) or at a later session (delayed PCI). Randomized trials comparing these strategies have not been performed; cohort studies have not identified consistent differences in safety or efficacy between the two strategies. Ad hoc PCI has increased in prevalence over the past decade and is the default strategy for treating acute coronary syndromes. However, questions about its appropriateness for some patients with stable symptoms have been raised by the results of recent large trials comparing PCI to medical therapy or bypass surgery. Ad hoc PCI for stable ischemic heart disease requires preprocedural planning, and reassessment after diagnostic angiography must be performed to ensure its appropriateness. Patients may prefer ad hoc PCI because it is convenient. Payers may prefer ad hoc PCI because it is cost-efficient. The majority of data confirm equivalent outcomes in ad hoc versus delayed PCI. However, there are some situations in which delayed PCI may be safer or yield better outcomes. This document reviews patient subsets and clinical situations in which one strategy is preferable over the other. Copyright © 2012 Wiley Periodicals, Inc.

  7. Typicality Mediates Performance during Category Verification in Both Ad-hoc and Well-defined Categories

    PubMed Central

    Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

    2012-01-01

    Background The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this population. Aims The present study explores the possible contributors to the typicality effect in persons with aphasia by analyzing and comparing data from both normal and language-disordered populations, from persons with aphasia with more semantic impairment versus those with less semantic impairment, and from two types of categories with very different boundary structure (ad-hoc vs. well-defined). Methods and procedures A total of 40 neurologically healthy adults (20 older, 20 younger) and 35 persons with aphasia (20 LSI (less-semantically impaired) patients, 15 MSI (more-semantically impaired) patients) participated in the study. Participants completed one of two tasks: either category verification for ad-hoc categories or category verification for well-defined categories. Outcomes and Results Neurologically healthy participants showed typicality effects for both ad-hoc and well-defined categories. MSI patients showed a typicality effect for well-defined categories, but not for ad-hoc categories, whereas LSI patients showed a typicality effect for ad-hoc categories, but not for well-defined categories. Conclusions These results suggest that the degree of semantic impairment mediates the typicality effect in persons with aphasia depending on the structure of the category. PMID:22261305

  8. Report of the ADE Ad Hoc Committee on Governance.

    ERIC Educational Resources Information Center

    ADE Bulletin, 2001

    2001-01-01

    Considers how decisions about curriculum, hiring, and institutional policies have changed due to increasing regulatory, legal, and financial pressures conflicting with ever-magnifying and multiplying sense of need. Identifies three dominant models of institutional governance--models that represent different emphases and that, for the purposes of…

  9. Sea Training at Maritime Academies Oversight. Hearings Before the Ad Hoc Select Subcommittee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries, House of Representatives, Ninety-Sixth Congress, Second Session on Sea Training of United States Merchant Marine Officers and Different Ways of Satisfying This Requirement at the Various Maritime Academies.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

    Recorded are minutes of hearings before the House Ad Hoc Select Subcommittee on Maritime Education and Training regarding the sea training of United States Merchant Marine officers. Examined are various approaches to meeting the sea training requirement, especially the options of maritime academy training vessels, sailing on U.S.-flag merchant…

  10. Performance Evaluation of Ad Hoc Routing Protocols in a Swarm of Autonomous Unmanned Aerial Vehicles

    DTIC Science & Technology

    2007-03-01

    research in mobile, ad hoc routing protocols. Broch , et al. performed a simulation comparison of the DSDV, DSR, AODV and Temporally-Ordered...July 6, 2005. [Bel58] R. Bellman, “On a Routing Problem,” in Quarterly of Applied Mathematics, 16(1), pp.87-90, 1958. [BJM04] J. Broch , D. B...vol. AD- A404703, 2002. [BMJ98] J. Broch , D. A. Maltz, D. B. Johnson, Y. Hu and J. Jetcheva, “A performance comparison of multi-hop wireless ad hoc

  11. A Decentralized VPN Service over Generalized Mobile Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Fujita, Sho; Shima, Keiichi; Uo, Yojiro; Esaki, Hiroshi

    We present a decentralized VPN service that can be built over generalized mobile ad-hoc networks (Generalized MANETs), in which topologies can be represented as a time-varying directed multigraph. We address wireless ad-hoc networks and overlay ad-hoc networks as instances of Generalized MANETs. We first propose an architecture to operate on various kinds of networks through a single set of operations. Then, we design and implement a decentralized VPN service on the proposed architecture. Through the development and operation of a prototype system we implemented, we found that the proposed architecture makes the VPN service applicable to each instance of Generalized MANETs, and that the VPN service makes it possible for unmodified applications to operate on the networks.

  12. Fuzzy Multiple Metrics Link Assessment for Routing in Mobile Ad-Hoc Network

    NASA Astrophysics Data System (ADS)

    Soo, Ai Luang; Tan, Chong Eng; Tay, Kai Meng

    2011-06-01

    In this work, we investigate on the use of Sugeno fuzzy inference system (FIS) in route selection for mobile Ad-Hoc networks (MANETs). Sugeno FIS is introduced into Ad-Hoc On Demand Multipath Distance Vector (AOMDV) routing protocol, which is derived from its predecessor, Ad-Hoc On Demand Distance Vector (AODV). Instead of using the conventional way that considering only a single metric to choose the best route, our proposed fuzzy decision making model considers up to three metrics. In the model, the crisp inputs of the three parameters are fed into an FIS and being processed in stages, i.e., fuzzification, inference, and defuzzification. Finally, after experiencing all the stages, a single value score is generated from the combination metrics, which will be used to measure all the discovered routes credibility. Results obtained from simulations show a promising improvement as compared to AOMDV and AODV.

  13. Time geography for ad-hoc shared-ride trip planning in mobile geosensor networks

    NASA Astrophysics Data System (ADS)

    Raubal, Martin; Winter, Stephan; Teβmann, Sven; Gaisbauer, Christian

    Ad-hoc shared-ride trip planning in an urban environment is a complex task within a non-deterministic transportation network. Mobile geosensor networks provide the technical environment for realizing ad-hoc shared-ride trip planning: Network nodes are autonomous agents that interact locally by ad-hoc short-range communication and arrange for shared rides. In a mobile geosensor network, communication costs are critical because of constraints regarding bandwidth, available energy, and memory. This paper introduces spatio-temporal concepts from time geography, which can be employed during the planning process to significantly reduce communication costs. We will integrate network-based algorithms and different wayfinding strategies to assist both shared-ride clients and hosts in finding optimal travel assignments. Multi-agent geosimulation in a real street network is used to demonstrate the applicability of the approach and quantitatively confirm the theoretically foreseen reduction in communication costs.

  14. History of the Standing Joint Force Headquarters for Elimination (SJFHQ-E): No More Ad Hoc

    DTIC Science & Technology

    2014-05-22

    Approved for Public Release; Distribution is Unlimited THE HISTORY OF THE STANDING JOINT FORCE HEADQUARTERS FOR ELIMINATION (SJFHQ-E): “NO MORE AD... Elimination (SJFHQ-E): “No More Ad Hoc” Approved by: __________________________________, Monograph Director Daniel G. Cox, Ph.D...THE HISTORY OF THE STANDING JOINT FORCE HEADQUARTERS FOR ELIMINATION (SJFHQ-E): “NO MORE AD HOC,” by LTC Kristofer D. Hopkins, U.S. Army, 54 pages

  15. Reliable on-demand multicast routing with congestion control in wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Tang, Ken; Gerla, Mario

    2001-07-01

    In this paper, we address the congestion control multicast routing problem in wireless ad hoc networks through the medium access control (MAC) layer. We first introduce the Broadcast Medium Window (BMW) MAC protocol, which provides reliable delivery to broadcast packets at the MAC layer. We then extend the wireless On-Demand Multicast Routing Protocol (ODMRP) to facilitate congestion control in ad hoc networks using BMW. Through simulation, we show that ODMRP with congestion control adapts well to multicast sources that are aggressive in data transmissions.

  16. Routing Protocols to Minimize the Number of Route Disconnections for Communication in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2009-09-01

    Broch , "DSR: The Dynamic Source Routing Protocol for Multi-hop Wireless Ad hoc Networks," in Ad hoc Networking, Chapter 5, C. E. Perkins, Eds. Addison...Project Report: 09/23/2008 to 09/22/2009 W911NF-08-2-0061 References [I] J. Broch , D. A. Maltz, D. B. Johnson, Y. C. Hu and J. Jetcheva, "A...and Mobile Computing, Vol. 2, pp. 723 - 726, Sept. 2005. [4] D. B. Johnson, D. A. Maltz and J. Broch , "DSR: The Dynamic Source Routing Protocol for

  17. 29 CFR 1912.2 - Types of standards advisory committees.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards in areas where there is frequent rulemaking and the use of ad hoc committees is impractical; and (b) Ad hoc committees which are established to render advice in particular rulemaking proceedings....

  18. Using Dominating Sets to Improve the Performance of Mobile Ad Hoc Networks

    DTIC Science & Technology

    2005-09-01

    Communications Research Group (CCRG) directed by J.J., and students (Cintia, Nacho, Kumar and Venkatesh ) in Katia’s lab for their fellowship. I cannot...wireless conference, pages 156–162, 2002. [41] Katia Obraczka, Kumar Viswanath , and Gene Tsudik. Flooding for reliable multicast in multi-hop ad hoc

  19. An Architecture for Enabling Migration of Tactical Networks to Future Flexible Ad Hoc WBWF

    DTIC Science & Technology

    2010-09-01

    stratum From PHY to radio Ad Hoc routing IP and legacy compatible Facilities for securing WBWF protocols Interfaces with OAM for local and remote ...OTA) supervision Support of (optional) GNSS interface (positioning and synchronisation features) Non Access Stratum Access Stratum W F D o m...through Security SAPs Management Plane : Local and remote management of equipment, radio interface, network guarantees proper configuration and

  20. A Comprehensive Performance Comparison of On-Demand Routing Protocols in Mobile Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Khan, Jahangir; Hayder, Syed Irfan

    Mobile ad hoc network is an autonomous system of mobile nodes connected by wireless links. Each node operates not only as an end system, but also as a router to forward packets. The nodes are free to move about and organize themselves on a fly. In this paper we focus on the performance of the on-demand routing protocols such as DSR and AODV in ad-hoc networks. We have observed the performance change of each protocol through simulation with varying the data in intermediate nodes and to compare data throughput in each mobile modes of each protocol to analyze the packet fraction for application data. The objective of this work is to evaluate two routing protocols such as On-demand behavior, namely, Ad hoc Demand Distance vector (AODV) and Dynamic Source Routing (DSR), for wireless ad hoc networks based on performance of intermediate nodes for the delivery of data form source to destination and vice versa in order to compare the efficiency of throughput in the neighbors nodes. To overcome we have proposed OPNET simulator for performance comparison of hop to hop delivery of data packet in autonomous system.

  1. The 5th Meeting of the Ad Hoc Panel on Terminal Configured Vehicles

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A report of the fifth meeting of the NASA Research and Technology Advisory Council, Ad Hoc panel on Terminal Configured Vehicles is presented. Some of the following topics were discussed; (1) microwave landing systems; (2) whole word computer system status; (3) flight path angle control: (4) VTOL approaches and landing technology; and (5) simulation study in wind shear.

  2. Final Report of the IAG AD Hoc Working Group on Global Change

    NASA Technical Reports Server (NTRS)

    Dickey, Jean O.

    1995-01-01

    None given. Paper gives final report of the IAG ad hoc working group on global change. They made three main recommendations to the group: 1. the post of and IAG liaison or representative to the IGBP should be established. 2. A new core program,.

  3. Combining Infrastructure and Ad Hoc Collaboration for Data Management in Mobile Wireless Networks

    DTIC Science & Technology

    2005-01-01

    Elizabeth M. Royer. "Ad hoc On-Demand Distance Vector Routing." Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications...Charles Perkins, ACM SIGCOMM󈨢 Conference on Communications Architectures, Protocols and Applications 22. Vincent D. Park and M. Scott Corson , A

  4. Reputation-Based Internet Protocol Security: A Multilayer Security Framework for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-09-01

    opportunity to pursue this degree while working in our organization. I must also thank Dr. Rusty O. Baldwin and Mr. Juan Lopez , both whom provided...Intrusion Detection in Mobile Ad Hoc Networks”. Wireless/Mobile Network Security, 170–196, 2006. 7. Ariza-Quintana, A., E. Casilari, and A.T. Cabrera

  5. Validity of using ad hoc methods to analyze secondary traits in case-control association studies.

    PubMed

    Yung, Godwin; Lin, Xihong

    2016-12-01

    Case-control association studies often collect from their subjects information on secondary phenotypes. Reusing the data and studying the association between genes and secondary phenotypes provide an attractive and cost-effective approach that can lead to discovery of new genetic associations. A number of approaches have been proposed, including simple and computationally efficient ad hoc methods that ignore ascertainment or stratify on case-control status. Justification for these approaches relies on the assumption of no covariates and the correct specification of the primary disease model as a logistic model. Both might not be true in practice, for example, in the presence of population stratification or the primary disease model following a probit model. In this paper, we investigate the validity of ad hoc methods in the presence of covariates and possible disease model misspecification. We show that in taking an ad hoc approach, it may be desirable to include covariates that affect the primary disease in the secondary phenotype model, even though these covariates are not necessarily associated with the secondary phenotype. We also show that when the disease is rare, ad hoc methods can lead to severely biased estimation and inference if the true disease model follows a probit model instead of a logistic model. Our results are justified theoretically and via simulations. Applied to real data analysis of genetic associations with cigarette smoking, ad hoc methods collectively identified as highly significant (P<10-5) single nucleotide polymorphisms from over 10 genes, genes that were identified in previous studies of smoking cessation. © 2016 WILEY PERIODICALS, INC.

  6. Protocols for Detection and Removal of Wormholes for Secure Routing and Neighborhood Creation in Wireless Ad Hoc Networks

    ERIC Educational Resources Information Center

    Hayajneh, Thaier Saleh

    2009-01-01

    Wireless ad hoc networks are suitable and sometimes the only solution for several applications. Many applications, particularly those in military and critical civilian domains (such as battlefield surveillance and emergency rescue) require that ad hoc networks be secure and stable. In fact, security is one of the main barriers to the extensive use…

  7. Protocols for Detection and Removal of Wormholes for Secure Routing and Neighborhood Creation in Wireless Ad Hoc Networks

    ERIC Educational Resources Information Center

    Hayajneh, Thaier Saleh

    2009-01-01

    Wireless ad hoc networks are suitable and sometimes the only solution for several applications. Many applications, particularly those in military and critical civilian domains (such as battlefield surveillance and emergency rescue) require that ad hoc networks be secure and stable. In fact, security is one of the main barriers to the extensive use…

  8. Ad Hoc Supervision of General Practice Registrars as a "Community of Practice": Analysis, Interpretation and Re-Presentation

    ERIC Educational Resources Information Center

    Clement, T.; Brown, J.; Morrison, J.; Nestel, D.

    2016-01-01

    General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also…

  9. Ad Hoc Supervision of General Practice Registrars as a "Community of Practice": Analysis, Interpretation and Re-Presentation

    ERIC Educational Resources Information Center

    Clement, T.; Brown, J.; Morrison, J.; Nestel, D.

    2016-01-01

    General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also…

  10. 76 FR 71308 - Codex Alimentarius Commission: Meeting of the Ad Hoc Intergovernmental Codex Task Force on Animal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Food Safety and Inspection Service Codex Alimentarius Commission: Meeting of the Ad Hoc... United States (U.S.) positions that will be discussed at the 6th Session of the Ad Hoc...

  11. Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks

    PubMed Central

    Vara, M. Isabel; Campo, Celeste

    2015-01-01

    Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead. PMID:26205272

  12. Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks.

    PubMed

    Vara, M Isabel; Campo, Celeste

    2015-07-20

    Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead.

  13. An Ad-Hoc Adaptive Pilot Model for Pitch Axis Gross Acquisition Tasks

    NASA Technical Reports Server (NTRS)

    Hanson, Curtis E.

    2012-01-01

    An ad-hoc algorithm is presented for real-time adaptation of the well-known crossover pilot model and applied to pitch axis gross acquisition tasks in a generic fighter aircraft. Off-line tuning of the crossover model to human pilot data gathered in a fixed-based high fidelity simulation is first accomplished for a series of changes in aircraft dynamics to provide expected values for model parameters. It is shown that in most cases, for this application, the traditional crossover model can be reduced to a gain and a time delay. The ad-hoc adaptive pilot gain algorithm is shown to have desirable convergence properties for most types of changes in aircraft dynamics.

  14. An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks.

    PubMed

    Penumalli, Chakradhar; Palanichamy, Yogesh

    2015-01-01

    A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results.

  15. PNNI routing support for ad hoc mobile networking: The multilevel case

    SciTech Connect

    Martinez, L.; Sholander, P.; Tolendino, L.

    1998-01-01

    This contribution extends the Outside Nodal Hierarchy List (ONHL) procedures described in ATM Forum Contributions 97-0766 and 97-0933. These extensions allow multiple mobile networks to form either an ad hoc network or an extension of a fixed PNNI infrastructure. A previous contribution (97-1073) covered the simplest case where the top-most Logical Group Nodes (LGNs), in those mobile networks, all resided at the same level in a PNNI hierarchy. This contribution covers the more general case wherein those top-most LGNs may reside at different PNNI hierarchy levels. Both of the SNL contributions consider flat ad hoc network architectures in the sense that each mobile network always participates in the PNNI hierarchy at the pre-configured level of its top-most LGN.

  16. Analysis and Proposal of Position-Based Routing Protocols for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Okada, Hiraku; Takano, Akira; Mase, Kenichi

    One of the most promising applications of a mobile ad hoc network is a vehicular ad hoc network (VANET). Each vehicle is aware of its position information by GPS or other methods, so position-based routing is a useful approach in VANET. The position-based routing protocol can be classified roughly into a next-hop forwarding method and a directed flooding method. We evaluate performance of both methods by analytic approach and compare them in this paper. From the evaluation results, we conclude that it is effective for the position-based routing to choose either the next-hop forwarding method or the directed flooding method according to the environment. Then we propose the hybrid transmission method which can select one of them according to the environment, and clarify that the proposed method can keep the packet delivery ratio at a high level and reduce the delay time.

  17. The Ad Hoc process to strengthen the framework convention on climate change

    SciTech Connect

    Ramakrishna, K.; Deutz, A.M.; Jacobsen, L.A.

    1995-11-01

    The Woods Hole Research Center convened an International Conference on The Ad Hoc Process to Strengthen the Framework Convention on Climate Change in Woods Hole, MA, on October 7-9, 1995. The conference was conducted to examine the prospects for successful adoption of a protocol to the Framework Convention on Climate Change by 1997. In preparation for the Second session of the Ad Hoc Group on the Berlin Mandate, several governmental and nongovernmental representatives met in Woods Hole to discuss the process and possible outcome of the Berlin Mandate negotiations for a protocol or other legal instrument to strengthen the Convention. The conference was by invitation and all participants attended in their personal capacities.

  18. An optimized node-disjoint multipath routing scheme in mobile ad hoc

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Liang, Mangui; Liu, Zhiyu

    2016-02-01

    In mobile ad hoc networks (MANETs), link failures are caused frequently because of node’s mobility and use of unreliable wireless channels for data transmission. Multipath routing strategy can cope with the problem of the traffic overloads while balancing the network resource consumption. In the paper, an optimized node-disjoint multipath routing (ONMR) protocol based on ad hoc on-demand vector (AODV) is proposed to establish effective multipath to enhance the network reliability and robustness. The scheme combines the characteristics of reverse AODV (R-AODV) strategy and on-demand node-disjoint multipath routing protocol to determine available node-disjoint routes with minimum routing control overhead. Meanwhile, it adds the backup routing strategy to make the process of data salvation more efficient in case of link failure. The results obtained through various simulations show the effectiveness of the proposed scheme in terms of route availability, control overhead and packet delivery ratio.

  19. PNNI routing support for ad hoc mobile networking: A flat architecture

    SciTech Connect

    Martinez, L.; Sholander, P.; Tolendino, L.

    1997-12-01

    This contribution extends the Outside Nodal Hierarchy List (ONHL) procedures described in ATM Form Contribution 97-0766. These extensions allow multiple mobile networks to form either an ad hoc network or an extension of a fixed PNNI infrastructure. This contribution covers the simplest case where the top-most Logical Group Nodes (LGNs), in those mobile networks, all reside at the same level in a PNNI hierarchy. Future contributions will cover the general case where those top-most LGNs reside at different hierarchy levels. This contribution considers a flat ad hoc network architecture--in the sense that each mobile network always participates in the PNNI hierarchy at the preconfigured level of its top-most LGN.

  20. Design of free patterns of nanocrystals with ad hoc features via templated dewetting

    NASA Astrophysics Data System (ADS)

    Aouassa, M.; Berbezier, I.; Favre, L.; Ronda, A.; Bollani, M.; Sordan, R.; Delobbe, A.; Sudraud, P.

    2012-07-01

    Design of monodisperse ultra-small nanocrystals (NCs) into large scale patterns with ad hoc features is demonstrated. The process makes use of solid state dewetting of a thin film templated through alloy liquid metal ion source focused ion beam (LMIS-FIB) nanopatterning. The solid state dewetting initiated at the edges of the patterns controllably creates the ordering of NCs with ad hoc placement and periodicity. The NC size is tuned by varying the nominal thickness of the film while their position results from the association of film retraction from the edges of the lay out and Rayleigh-like instability. The use of ultra-high resolution LMIS-FIB enables to produce monocrystalline NCs with size, periodicity, and placement tunable as well. It provides routes for the free design of nanostructures for generic applications in nanoelectronics.

  1. Vehicular ad hoc network for a surveillance system using multifrequency band enhancement

    NASA Astrophysics Data System (ADS)

    Bunruangses, Montree; Sunat, Khamron; Mitatha, Somsak; Yupapin, Preecha P.

    2010-09-01

    We present a new design of a surveillance system via a vehicular ad hoc network (VANET) integrated by a 3-G or 4-G cellular wireless network. We propose dense wavelength division multiplexing wavelength enhancement for increasing the channel capacity and signal security. Increase in the number of channels can be obtained by increasing the wavelength density. Signal security is introduced by a specific wavelength filter controlled by the central operator. Optical communication wavelength enhancement is reviewed. The advantage of this proposed system is that it can easily be implemented and incorporated into the existing communication link in either a cellular or ad hoc wireless system, where signal security and hence privacy can be provided.

  2. Reliable energy-aware routing with unreliable links in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Bao, Yanru; Shu, Yantai; Wang, Xin; Yu, Li

    2007-09-01

    Since most ad hoc mobile devices today operate on batteries, energy-aware routings and power control techniques in wireless networks have drawn considerable research interests recently. This paper presents a reliable energy-aware routing algorithm (REARP) for unreliable ad hoc networks. The lifetime of the whole network and the energy cost for each packet are considered simultaneously in the routing processes of the REARP. Different from the formers, the energy cost of the link layer retransmission is also computed into the total energy consumption. Moreover, the REARP appropriately adjusts the transmission power by systematically integrating the reliability and power control techniques. We conducted extensive simulations to evaluate the performance of the new routing algorithms compared to a number of existing routing algorithms.

  3. Enhancements for distributed certificate authority approaches for mobile wireless ad hoc networks.

    SciTech Connect

    Van Leeuwen, Brian P.; Michalski, John T.; Anderson, William Erik

    2003-12-01

    Mobile wireless ad hoc networks that are resistant to adversarial manipulation are necessary for distributed systems used in military and security applications. Critical to the successful operation of these networks, which operate in the presence of adversarial stressors, are robust and efficient information assurance methods. In this report we describe necessary enhancements for a distributed certificate authority (CA) used in secure wireless network architectures. Necessary cryptographic algorithms used in distributed CAs are described and implementation enhancements of these algorithms in mobile wireless ad hoc networks are developed. The enhancements support a network's ability to detect compromised nodes and facilitate distributed CA services. We provide insights to the impacts the enhancements will have on network performance with timing diagrams and preliminary network simulation studies.

  4. On knowledge transfer management as a learning process for ad hoc teams

    NASA Astrophysics Data System (ADS)

    Iliescu, D.

    2017-08-01

    Knowledge management represents an emerging domain becoming more and more important. Concepts like knowledge codification and personalisation, knowledge life-cycle, social and technological dimensions, knowledge transfer and learning management are integral parts. Focus goes here in the process of knowledge transfer for the case of ad hoc teams. The social dimension of knowledge transfer plays an important role. No single individual actors involved in the process, but a collective one, representing the organisation. It is critically important for knowledge to be managed from the life-cycle point of view. A complex communication network needs to be in place to supports the process of knowledge transfer. Two particular concepts, the bridge tie and transactive memory, would eventually enhance the communication. The paper focuses on an informational communication platform supporting the collaborative work on knowledge transfer. The platform facilitates the creation of a topic language to be used in knowledge modelling, storage and reuse, by the ad hoc teams.

  5. Forming an ad-hoc nearby storage, based on IKAROS and social networking services

    NASA Astrophysics Data System (ADS)

    Filippidis, Christos; Cotronis, Yiannis; Markou, Christos

    2014-06-01

    We present an ad-hoc "nearby" storage, based on IKAROS and social networking services, such as Facebook. By design, IKAROS is capable to increase or decrease the number of nodes of the I/O system instance on the fly, without bringing everything down or losing data. IKAROS is capable to decide the file partition distribution schema, by taking on account requests from the user or an application, as well as a domain or a Virtual Organization policy. In this way, it is possible to form multiple instances of smaller capacity higher bandwidth storage utilities capable to respond in an ad-hoc manner. This approach, focusing on flexibility, can scale both up and down and so can provide more cost effective infrastructures for both large scale and smaller size systems. A set of experiments is performed comparing IKAROS with PVFS2 by using multiple clients requests under HPC IOR benchmark and MPICH2.

  6. Modelling of Medium Access Control (MAC) Protocols for Mobile Ad-Hoc Networks

    DTIC Science & Technology

    2005-06-01

    Slot IP Internet Protocol LAN Local Area Network MAC Medium Access Control MACAW Medium Access Protocol for Wireless LANs MANET Mobile Ad-hoc...Unforced state – It waits after entering the state until it is invoked by another process or an interrupt. It is in dark grey on this report, and red ... green in OPNET. A MAC process model is built for general initialisations of the MAC module, and to invoke the selected MAC protocol process model

  7. Interoperable Security, Routing and Quality of Service for Ad-Hoc Network Mobility

    DTIC Science & Technology

    2006-12-01

    Vector (AODV) [1], Dynamic Source Routing (DSR), Optimized Link State Routing ( OLSR ) [2], and Topology Broadcast Based on Reverse Path Forwarding... OLSR and TBRPF, do provide shortest-path routing and more extensive topology information, but at the cost of high control overhead for topology...e.g. OLSR [2], the Core Extraction Distributed Ad-hoc Routing (CEDAR) protocol [6], and the simple gateway protocol proposed by Wu and Li [7], OSPF

  8. Network Size and Connectivity in Mobile and Stationary Ad Hoc Networks

    DTIC Science & Technology

    2014-05-01

    mobile ad hoc networks ( MANETs ) is that routes consisting of multiple hops will be available to connect those nodes that lack line-of- sight connectivity...The practical utility of MANET depends on this assumption being true and, for a mobile network, remaining true during mobility. In previous work...terrain will affect MANETs when nodes move. It does not incorporate any speci- fics about network management or routing beyond assuming a fixed routing

  9. Trust Management in Mobile Ad Hoc Networks for Bias Minimization and Application Performance Maximization

    DTIC Science & Technology

    2014-02-26

    analysis Application-level trust optimization Reliability assessment a b s t r a c t Trust management for mobile ad hoc networks ( MANETs ) has emerged as...this paper we address the performance issue of trust management protocol design for MANETs in two important areas: trust bias minimization and...application performance maximization. By means of a novel model- based approach to model the ground truth status of mobile nodes in MANETs as the basis for

  10. Effects of Data Replication on Data Exfiltration in Mobile Ad Hoc Networks Utilizing Reactive Protocols

    DTIC Science & Technology

    2015-03-01

    that file replication can increase data survivability in a system where the amount of data generated exceeds the capability to ex-filtrate the data, but...traditional, fixed infrastructure network creates an abundance of factors to examine. Such factors in- clude overhead from network routing and file system...distinctions critical. This thesis will focus primarily on FANETs, but will use the term MANET to generalize all mobile ad hoc networks, unless noted

  11. Interactive Operations for Visualization of Ad-Hoc Sensor System Domains

    DTIC Science & Technology

    2005-11-01

    Interactive Operations for Visualization of Ad-hoc Sensor System Domains Mark A. Livingston and Evan V. Herbst Virtual Reality Laboratory Naval...sensing technologies in the field. Future enhancements may include airborne relays, improved sensors, and new types of sensors, but we do not want to...operations implemented thus far use only the first three variables; the others are included for compatibility of format and potential future use. The

  12. On Throughput Improvement of Wireless Ad Hoc Networks with Hidden Nodes

    NASA Astrophysics Data System (ADS)

    Choi, Hong-Seok; Lim, Jong-Tae

    In this letter, we present the throughput analysis of the wireless ad hoc networks based on the IEEE 802.11 MAC (Medium Access Control). Especially, our analysis includes the case with the hidden node problem so that it can be applied to the multi-hop networks. In addition, we suggest a new channel access control algorithm to maximize the network throughput and show the usefulness of the proposed algorithm through simulations.

  13. EGPS: An Efficient Privacy Preserving Scheme for Vehicular ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Baokang; Su, Xiangyu; Su, Jinshu; Song, Ziming; Sun, Yipin; Tao, Jing; Tang, Yong; Chen, Shuhui; Zhao, Guohong; Chen, Yijiao

    2010-09-01

    In this paper, we propose EGPS, an efficient privacy preserving scheme for vehicular ad hoc networks. The EGPS scheme is based on a very efficient group signature and Identity Based Cryptography(IBC) techniques. Several security properties of EGPS, including the correctness and unforgeability have been proved. Furthermore, EGPS is also proved to be more efficient than GSIS, which is currently one of the best state-of-the-art VANET privacy preserving schemes.

  14. Adaptive Demand-Driven Multicast Routing in Multi-Hop Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-05-06

    16] L. Ji and M. S. Corson . A Lightweight Adaptive Multicast Algorithm. In Proceedings of IEEE GLOBECOM ’98, pages 1036–1042, December 1998. [17] L...Ji and M. S. Corson . Differential Destination Multicast (DDM) Specification. Internet- Draft, draft-ietf-manet-ddm-00.txt, July 2000. Work in...3 [30] Charles E. Perkins, Elizabeth M. Royer, and Samir R. Das. Ad Hoc On Demand Distance Vector (AODV) Routing. Internet-Draft, draft-ietf-manet

  15. A Performance Comparison of On-Demand Multicast Routing Protocols for Ad Hoc Networks

    DTIC Science & Technology

    2004-12-15

    33–44, October 2001. [10] L. Ji and M. S. Corson . A Lightweight Adaptive Multicast Algorithm. In Proceedings of IEEE GLOBECOM ’98, pages 1036–1042...December 1998. [11] L. Ji and M. S. Corson . Differential Destination Multicast (DDM) Specification. Internet- Draft, draft-ietf-manet-ddm-00.txt, July... Elizabeth M. Royer and Charles E. Perkins. Multicast Operation of the Ad-hoc On- Demand Distance Vector Routing Protocol. In Proceedings of the Fifth

  16. Systematic lossy error protection for video transmission over wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoqing; Rane, Shantanu; Girod, Bernd

    2005-07-01

    Wireless ad hoc networks present a challenge for error-resilient video transmission, since node mobility and multipath fading result in time-varying link qualities in terms of packet loss ratio and available bandwidth. In this paper, we propose to use a systematic lossy error protection (SLEP) scheme for video transmission over wireless ad hoc networks. The transmitted video signal has two parts-a systematic portion consisting of a video sequence transmitted without channel coding over an error-prone channel, and error protection information consisting of a bitstream generated by Wyner-Ziv encoding of the video sequence. Using an end-to-end video distortion model in conjunction with online estimates of packet loss ratio and available bandwidth, the optimal Wyner-Ziv description can be selected dynamically according to current channel conditions. The scheme can also be applied to choose one path for transmission from amongst multiple candidate routes with varying available bandwidths and packet loss ratios, so that the expected end-to-end video distortion is maximized. Experimental results of video transmission over a simulated ad hoc wireless network shows that the proposed SLEP scheme outperforms the conventional application layer FEC approach in that it provides graceful degradation of received video quality over a wider range of packet loss ratios and is less susceptible to inaccuracy in the packet loss ratio estimation.

  17. Capacity-Delay Trade-Off in Collaborative Hybrid Ad-Hoc Networks with Coverage Sensing

    PubMed Central

    Chen, Lingyu; Luo, Wenbin; Liu, Chen; Hong, Xuemin; Shi, Jianghong

    2017-01-01

    The integration of ad hoc device-to-device (D2D) communications and open-access small cells can result in a networking paradigm called hybrid the ad hoc network, which is particularly promising in delivering delay-tolerant data. The capacity-delay performance of hybrid ad hoc networks has been studied extensively under a popular framework called scaling law analysis. These studies, however, do not take into account aspects of interference accumulation and queueing delay and, therefore, may lead to over-optimistic results. Moreover, focusing on the average measures, existing works fail to give finer-grained insights into the distribution of delays. This paper proposes an alternative analytical framework based on queueing theoretic models and physical interference models. We apply this framework to study the capacity-delay performance of a collaborative cellular D2D network with coverage sensing and two-hop relay. The new framework allows us to fully characterize the delay distribution in the transform domain and pinpoint the impacts of coverage sensing, user and base station densities, transmit power, user mobility and packet size on the capacity-delay trade-off. We show that under the condition of queueing equilibrium, the maximum throughput capacity per device saturates to an upper bound of 0.7239 λb/λu bits/s/Hz, where λb and λu are the densities of base stations and mobile users, respectively. PMID:28134769

  18. Ad Hoc Categories and False Memories: Memory Illusions for Categories Created On-the-Spot.

    PubMed

    Soro, Jerônimo C; Ferreira, Mário B; Semin, Gün R; Mata, André; Carneiro, Paula

    2017-04-06

    Three experiments were designed to test whether experimentally created ad hoc associative networks evoke false memories. We used the DRM (Deese, Roediger, McDermott) paradigm with lists of ad hoc categories composed of exemplars aggregated toward specific goals (e.g., going for a picnic) that do not share any consistent set of features. Experiment 1 revealed considerable levels of false recognitions of critical words from ad hoc categories. False recognitions occurred even when the lists were presented without an organizing theme (i.e., the category's label). Experiments 1 and 2 tested whether (a) the ease of identifying the categories' themes, and (b) the lists' backward associative strength could be driving the effect. List identifiability did not correlate with false recognition, and the effect remained even when backward associative strength was controlled for. Experiment 3 manipulated the distractor items in the recognition task to address the hypothesis that the salience of unrelated items could be facilitating the occurrence of the phenomenon. The effect remained when controlling for this source of facilitation. These results have implications for assumptions made by theories of false memories, namely the preexistence of associations in the activation-monitoring framework and the central role of gist extraction in fuzzy-trace theory, while providing evidence of the occurrence of false memories for more dynamic and context-dependent knowledge structures. (PsycINFO Database Record

  19. Real Time Semantic Interoperability in AD HOC Networks of Geospatial Data Sources: Challenges, Achievements and Perspectives

    NASA Astrophysics Data System (ADS)

    Mostafavi, M. A.; Bakillah, M.

    2012-07-01

    Recent advances in geospatial technologies have made available large amount of geospatial data. Meanwhile, new developments in Internet and communication technologies created a shift from isolated geospatial databases to ad hoc networks of geospatial data sources, where data sources can join or leave the network, and form groups to share data and services. However, effective integration and sharing of geospatial data among these data sources and their users are hampered by semantic heterogeneities. These heterogeneities affect the spatial, temporal and thematic aspects of geospatial concepts. There have been many efforts to address semantic interoperability issues in the geospatial domain. These efforts were mainly focused on resolving heterogeneities caused by different and implicit representations of the concepts. However, many approaches have focused on the thematic aspects, leaving aside the explicit representation of spatial and temporal aspects. Also, most semantic interoperability approaches for networks have focused on automating the semantic mapping process. However, the ad hoc network structure is continuously modified by source addition or removal, formation of groups, etc. This dynamic aspect is often neglected in those approaches. This paper proposes a conceptual framework for real time semantic interoperability in ad hoc networks of geospatial data sources. The conceptual framework presents the fundamental elements of real time semantic interoperability through a hierarchy of interrelated semantic states and processes. Then, we use the conceptual framework to set the discussion on the achievements that have already been made, the challenges that remain to be addressed and perspectives with respect to these challenges.

  20. A Dirichlet reputation system in reliable routing of wireless ad hoc network

    SciTech Connect

    Yang, Dr. Li; Cui, Xiaohui; Cemerlic, Alma

    2010-01-01

    Ad hoc networks are very helpful in situations when no fixed network infrastructure is available, such as natural disasters and military conflicts. In such a network, all wireless nodes are equal peers simultaneously serving as both senders and routers for other nodes. Therefore, how to route packets through reliable paths becomes a fundamental problems when behaviors of certain nodes deviate from wireless ad hoc routing protocols. We proposed a novel Dirichlet reputation model based on Bayesian inference theory which evaluates reliability of each node in terms of packet delivery. Our system offers a way to predict and select a reliable path through combination of first-hand observation and second-hand reputation reports. We also proposed moving window mechanism which helps to adjust ours responsiveness of our system to changes of node behaviors. We integrated the Dirichlet reputation into routing protocol of wireless ad hoc networks. Our extensive simulation indicates that our proposed reputation system can improve good throughput of the network and reduce negative impacts caused by misbehaving nodes.

  1. Ad hoc CubeSat constellations: Secondary launch coverage and distribution

    NASA Astrophysics Data System (ADS)

    Marinan, A.; Nicholas, A.; Cahoy, K.

    The primary purpose of a constellation is to obtain global measurements with improved spatial and temporal resolution. The small size, low cost, standardized form factor, and increasing availability of commercial parts for CubeSats make them ideal for use in constellations. However, without taking advantage of secondary payload opportunities, it would be costly to launch and distribute a CubeSat constellation into a specific configuration. A cost-effective way to launch a constellation of CubeSats is via consecutive secondary payload launch opportunities, but the resulting constellation would be an ad hoc mix of orbit parameters. We focus on the feasibility of cobbling together constellation-like functionality from multiple secondary payload opportunities. Each participating CubeSat (or set of CubeSats) per launch could have completely different orbital parameters, even without propulsion onboard the CubeSats or intermediate transfer carriers. We look at the ground coverages that could be obtained for a constellation of five to six orbital planes with one to six satellites in each plane. We analyze past and announced future launch opportunities for CubeSats, including launch platforms supported by the NASA Educational Launch of Nanosatellites (ELaNa). We consider combinations of possible launch locations and temporal spacings over the course of one year and simulate the resulting ground coverage patterns and revisit times for an ad hoc constellation using these launch opportunities. We perform this analysis for two separate case studies - one with only US launches and one with both US and non-US opportunities - and vary the number of satellites per orbital plane. Typical CubeSat mission lifetimes and deorbit times for low-altitude orbits are included in these analyses. The ad hoc constellation results are compared to coverage from uniformly-placed LEO constellations and are quantified in terms of revisit time, time to 100% global coverage, and response time. For mu

  2. Dynamic autonomous routing technology for IP-based satellite ad hoc networks

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofei; Deng, Jing; Kostas, Theresa; Rajappan, Gowri

    2014-06-01

    IP-based routing for military LEO/MEO satellite ad hoc networks is very challenging due to network and traffic heterogeneity, network topology and traffic dynamics. In this paper, we describe a traffic priority-aware routing scheme for such networks, namely Dynamic Autonomous Routing Technology (DART) for satellite ad hoc networks. DART has a cross-layer design, and conducts routing and resource reservation concurrently for optimal performance in the fluid but predictable satellite ad hoc networks. DART ensures end-to-end data delivery with QoS assurances by only choosing routing paths that have sufficient resources, supporting different packet priority levels. In order to do so, DART incorporates several resource management and innovative routing mechanisms, which dynamically adapt to best fit the prevailing conditions. In particular, DART integrates a resource reservation mechanism to reserve network bandwidth resources; a proactive routing mechanism to set up non-overlapping spanning trees to segregate high priority traffic flows from lower priority flows so that the high priority flows do not face contention from low priority flows; a reactive routing mechanism to arbitrate resources between various traffic priorities when needed; a predictive routing mechanism to set up routes for scheduled missions and for anticipated topology changes for QoS assurance. We present simulation results showing the performance of DART. We have conducted these simulations using the Iridium constellation and trajectories as well as realistic military communications scenarios. The simulation results demonstrate DART's ability to discriminate between high-priority and low-priority traffic flows and ensure disparate QoS requirements of these traffic flows.

  3. T2AR: trust-aware ad-hoc routing protocol for MANET.

    PubMed

    Dhananjayan, Gayathri; Subbiah, Janakiraman

    2016-01-01

    Secure data transfer against the malicious attacks is an important issue in an infrastructure-less independent network called mobile ad-hoc network (MANET). Trust assurance between MANET nodes is the key parameter in the high-security provision under dynamic topology variations and open wireless constraints. But, the malicious behavior of nodes reduces the trust level of the nodes that leads to an insecure data delivery. The increase in malicious attacks causes the excessive energy consumption that leads to a reduction of network lifetime. The lack of positional information update of the nodes in ad-hoc on-demand vector (AODV) protocol during the connection establishment offers less trust level between the nodes. Hence, the trust rate computation using energy and mobility models and its update are the essential tasks for secure data delivery. This paper proposes a trust-aware ad-hoc routing (T2AR) protocol to improve the trust level between the nodes in MANET. The proposed method modifies the traditional AODV routing protocol with the constraints of trust rate, energy, mobility based malicious behavior prediction. The packet sequence ID matching from the log reports of neighbor nodes determine the trust rate that avoids the malicious report generation. Besides, the direct and indirect trust observation schemes utilization increases the trust level. Besides, the received signal strength indicator utilization determines the trusted node is within the communication range or not. The comparative analysis between the proposed T2AR with the existing methods such as TRUNCMAN, RBT, GR, FBR and DICOTIDS regarding the average end-to-end delay, throughput, false positives, packet delivery ratio shows the effectiveness of T2AR in the secure MANET environment design.

  4. Soil Property Mapping Over Large Areas Using Sparse Ad-hoc Samples

    NASA Astrophysics Data System (ADS)

    Zhu, A.; Liu, J.

    2011-12-01

    Information on spatial variation of soil properties over large areas is a critical input for environmental modeling at large scales. Yet, quality information on soil spatial variation over large areas is difficult to obtain due to the large number of field samples required. Existing samples are often sparse and ad-hoc. The soil property maps created from these samples using existing techniques are not only at low quality but also lack the uncertainty information. This paper presents a new approach to map soil properties and quantify uncertainty in the derived soil property maps over large areas using sparse and ad-hoc samples. The underlying assumption of this new approach is the soil-landscape concept which stipulates that the more similar the environment conditions between two locations the more similar the soil property values are between the two sites. Under this assumption each sample can be considered as a representative over areas of similar environmental conditions. The level of representation of an individual sample for an unsampled location can be approximated by the similarity between their respective environment conditions. Based on this "individual representation" concept and with a Case-based Reasoning (CBR) approach soil property values at unsampled locations can be predicted and the uncertainty associated with each prediction can also be quantified based on their environmental similarity to individual samples. A case study over the Illy Region, a 50,000 km2 area in Xinjiang, Northwest China, has demonstrated that the approach can be an effective alternative for mapping soil property and quantifying uncertainty over large areas with sparse and ad-hoc samples.

  5. Design and implementation of a MIMO MAC protocol for ad hoc networking

    NASA Astrophysics Data System (ADS)

    Redi, Jason; Watson, Bill; Ramanathan, Ram; Basu, Prithwish; Tchakountio, Fabrice; Girone, Michael; Steenstrup, Martha

    2006-05-01

    Multiple Input Multiple Output (MIMO) provides the potential for significant gains in channel capacity and spectral efficiency through its use of multiple element antenna systems and space-time coding. There are numerous published accounts of experimental MIMO communications links with high numbers of transmit and receive antennas, as well as commercial products exploiting MIMO with smaller antenna configurations. However, the use of MIMO as a modulation scheme for mobile ad hoc networking has so far only been explored as part of a theoretic or simulation exercise. In this paper we describe the design and implementation of a MAC protocol for a MIMO system which is designed to exploit the capability of 8x10 MIMO for ad hoc networks. This work is unique in that from the start our design considered the specific capabilities and parameters of an existing 8x10 MIMO physical layer, including nonnegligible decoding delays, variable array size and coding schemes, as well as fixed frame sizes. Furthermore, given the bandwidths and antenna array sizes available, the physical layer design could achieve hundreds of megabits in link capacity, and our MAC protocol therefore needed to be designed and implemented in such a way as to maximize this capacity, particularly in a network multi-hop environment. Our MIMO-MAC protocol provides this capability while supporting multi-hop ad hoc networks through novel schemes for channel access, segmentation/reassembly, ARQ and link adaptation. This paper discusses the challenges and tradeoffs involved in developing a MAC for real MIMO hardware, and briefly describes a subset of our solutions to them.

  6. Dynamic fair node spectrum allocation for ad hoc networks using random matrices

    NASA Astrophysics Data System (ADS)

    Rahmes, Mark; Lemieux, George; Chester, Dave; Sonnenberg, Jerry

    2015-05-01

    Dynamic Spectrum Access (DSA) is widely seen as a solution to the problem of limited spectrum, because of its ability to adapt the operating frequency of a radio. Mobile Ad Hoc Networks (MANETs) can extend high-capacity mobile communications over large areas where fixed and tethered-mobile systems are not available. In one use case with high potential impact, cognitive radio employs spectrum sensing to facilitate the identification of allocated frequencies not currently accessed by their primary users. Primary users own the rights to radiate at a specific frequency and geographic location, while secondary users opportunistically attempt to radiate at a specific frequency when the primary user is not using it. We populate a spatial radio environment map (REM) database with known information that can be leveraged in an ad hoc network to facilitate fair path use of the DSA-discovered links. Utilization of high-resolution geospatial data layers in RF propagation analysis is directly applicable. Random matrix theory (RMT) is useful in simulating network layer usage in nodes by a Wishart adjacency matrix. We use the Dijkstra algorithm for discovering ad hoc network node connection patterns. We present a method for analysts to dynamically allocate node-node path and link resources using fair division. User allocation of limited resources as a function of time must be dynamic and based on system fairness policies. The context of fair means that first available request for an asset is not envied as long as it is not yet allocated or tasked in order to prevent cycling of the system. This solution may also save money by offering a Pareto efficient repeatable process. We use a water fill queue algorithm to include Shapley value marginal contributions for allocation.

  7. A Prototype System for Using Multiple Radios in Directional MANET (Mobile Ad Hoc Network): A NISE Funded Applied Research Project

    DTIC Science & Technology

    2013-09-01

    Technical Document 3276 September 2013 A Prototype System for using Multiple Radios in Directional MANET (Mobile Ad Hoc Network) A...point, it is difficult to employ directional antennas in a mobile ad hoc network ( MANET ) as most current radio and wireless networking protocols were...antennas in a MANET in a radio agnostic way by building networks out of dedicated point-to-point links. This document presents a protocol that accomplishes

  8. Analysis of the Robustness Dynamics of Wireless Mobile Ad Hoc Networks via Time Varying Dual Basis Representation

    DTIC Science & Technology

    2015-01-08

    between nodes to analyze the robustness of a wireless mobile ad hoc network ( MANET ) with a time-varying wireless channel. This spectral analysis and...performance of a network. Using a simulation of wireless devices in a MANET with a time- varying channel, we show that robustness is a function of...a single eigenvalue is evaluated. 1. Introduction Mobile ad hoc networks ( MANETs ) are complex systems that can be foreseen supporting

  9. Concept Detection and Using Concept in Ad-hoc of Microblog Search

    DTIC Science & Technology

    2012-11-01

    10,887,718 tweets with 200 tags and 2992055 tweets with 301 tags . We use character ASCII code to detect non-English tweets . In specifically, if a tweet ...hfang@ece.udel.edu Abstract: We report our system and experiments in TREC 2012 microblog Ad-hoc task. Our goal is to return most relevant tweets to...about 16 millions tweets over the period from Jan. 24th, 2011 to Feb. 8th, 2011. Each query is presented by short keywords and post time. Systems

  10. Performance Impacts of Lower-Layer Cryptographic Methods in Mobile Wireless Ad Hoc Networks

    SciTech Connect

    VAN LEEUWEN, BRIAN P.; TORGERSON, MARK D.

    2002-10-01

    In high consequence systems, all layers of the protocol stack need security features. If network and data-link layer control messages are not secured, a network may be open to adversarial manipulation. The open nature of the wireless channel makes mobile wireless mobile ad hoc networks (MANETs) especially vulnerable to control plane manipulation. The objective of this research is to investigate MANET performance issues when cryptographic processing delays are applied at the data-link layer. The results of analysis are combined with modeling and simulation experiments to show that network performance in MANETs is highly sensitive to the cryptographic overhead.

  11. Smart border: ad-hoc wireless sensor networks for border surveillance

    NASA Astrophysics Data System (ADS)

    He, Jun; Fallahi, Mahmoud; Norwood, Robert A.; Peyghambarian, Nasser

    2011-06-01

    Wireless sensor networks have been proposed as promising candidates to provide automated monitoring, target tracking, and intrusion detection for border surveillance. In this paper, we demonstrate an ad-hoc wireless sensor network system for border surveillance. The network consists of heterogeneously autonomous sensor nodes that distributively cooperate with each other to enable a smart border in remote areas. This paper also presents energy-aware and sleeping algorithms designed to maximize the operating lifetime of the deployed sensor network. Lessons learned in building the network and important findings from field experiments are shared in the paper.

  12. Joint Random Access and Power Control Game in Ad Hoc Networks with Noncooperative Users

    NASA Astrophysics Data System (ADS)

    Long, Chengnian; Guan, Xinping

    We consider a distributed joint random access and power control scheme for interference management in wireless ad hoc networks. To derive decentralized solutions that do not require any cooperation among the users, we formulate this problem as non-cooperative joint random access and power control game, in which each user minimizes its average transmission cost with a given rate constraint. Using supermodular game theory, the existence and uniqueness of Nash equilibrium are established. Furthermore, we present an asynchronous distributed algorithm to compute the solution of the game based on myopic best response updates, which converges to Nash equilibrium globally.

  13. A cooperative MAC protocol with error-aware relay selection for wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Liu, Shanzhi; Liu, Kai; Wang, Rui; Fang, Ruochen; Liu, Feng

    2017-01-01

    To solve performance degradation caused by channel fading, we propose a cooperative MAC protocol with error-aware relay selection for wireless ad hoc networks in this paper. In the protocol, the transmission error of data packet caused by channel fading are considered in order to achieve the best cooperative gain in the poor quality channel. In the relay selection process, potential relay nodes satisfying corresponding requirement can compete to sever as final relay node by means of priority selection and collision resolution process. Finally, simulation results show that the proposed protocol outperforms other protocol in terms of packet error rate and the saturation throughput.

  14. Assessment of interbreeding and introgression of farm genes into a small Scottish Atlantic salmon Salmo salar stock: ad hoc samples - ad hoc results?

    PubMed

    Verspoor, E; Knox, D; Marshall, S

    2016-12-01

    An eclectic set of tissues and existing data, including purposely collected samples, spanning 1997-2006, was used in an ad hoc assessment of hybridization and introgression of farmed wild Atlantic salmon Salmo salar in the small Loch na Thull (LnT) catchment in north-west Scotland. The catchment is in an area of marine farm production and contains freshwater smolt rearing cages. The LnT S. salar stock was found to be genetically distinctive from stocks in neighbouring rivers and, despite regular reports of feral farm S. salar, there was no evidence of physical or genetic mixing. This cannot be completely ruled out, however, and low level mixing with other local wild stocks has been suggested. The LnT population appeared underpinned by relatively smaller effective number of breeders (Neb ) and showed relatively low levels of genetic diversity, consistent with a small effective population size. Small sample sizes, an incomplete farm baseline and the use of non-diagnostic molecular markers, constrain the power of the analysis but the findings strongly support the LnT catchment having a genetically distinct wild S. salar population little affected by interbreeding with feral farm escapes. © 2016 The Fisheries Society of the British Isles.

  15. Energy-Aware Multipath Routing Scheme Based on Particle Swarm Optimization in Mobile Ad Hoc Networks

    PubMed Central

    Robinson, Y. Harold; Rajaram, M.

    2015-01-01

    Mobile ad hoc network (MANET) is a collection of autonomous mobile nodes forming an ad hoc network without fixed infrastructure. Dynamic topology property of MANET may degrade the performance of the network. However, multipath selection is a great challenging task to improve the network lifetime. We proposed an energy-aware multipath routing scheme based on particle swarm optimization (EMPSO) that uses continuous time recurrent neural network (CTRNN) to solve optimization problems. CTRNN finds the optimal loop-free paths to solve link disjoint paths in a MANET. The CTRNN is used as an optimum path selection technique that produces a set of optimal paths between source and destination. In CTRNN, particle swarm optimization (PSO) method is primly used for training the RNN. The proposed scheme uses the reliability measures such as transmission cost, energy factor, and the optimal traffic ratio between source and destination to increase routing performance. In this scheme, optimal loop-free paths can be found using PSO to seek better link quality nodes in route discovery phase. PSO optimizes a problem by iteratively trying to get a better solution with regard to a measure of quality. The proposed scheme discovers multiple loop-free paths by using PSO technique. PMID:26819966

  16. Intelligent QoS routing algorithm based on improved AODV protocol for Ad Hoc networks

    NASA Astrophysics Data System (ADS)

    Huibin, Liu; Jun, Zhang

    2016-04-01

    Mobile Ad Hoc Networks were playing an increasingly important part in disaster reliefs, military battlefields and scientific explorations. However, networks routing difficulties are more and more outstanding due to inherent structures. This paper proposed an improved cuckoo searching-based Ad hoc On-Demand Distance Vector Routing protocol (CSAODV). It elaborately designs the calculation methods of optimal routing algorithm used by protocol and transmission mechanism of communication-package. In calculation of optimal routing algorithm by CS Algorithm, by increasing QoS constraint, the found optimal routing algorithm can conform to the requirements of specified bandwidth and time delay, and a certain balance can be obtained among computation spending, bandwidth and time delay. Take advantage of NS2 simulation software to take performance test on protocol in three circumstances and validate the feasibility and validity of CSAODV protocol. In results, CSAODV routing protocol is more adapt to the change of network topological structure than AODV protocol, which improves package delivery fraction of protocol effectively, reduce the transmission time delay of network, reduce the extra burden to network brought by controlling information, and improve the routing efficiency of network.

  17. A Multihop Key Agreement Scheme for Wireless Ad Hoc Networks Based on Channel Characteristics

    PubMed Central

    Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks. PMID:23766725

  18. A Secure 3-Way Routing Protocols for Intermittently Connected Mobile Ad Hoc Networks

    PubMed Central

    Parasuraman, Ganesh Kumar

    2014-01-01

    The mobile ad hoc network may be partially connected or it may be disconnected in nature and these forms of networks are termed intermittently connected mobile ad hoc network (ICMANET). The routing in such disconnected network is commonly an arduous task. Many routing protocols have been proposed for routing in ICMANET since decades. The routing techniques in existence for ICMANET are, namely, flooding, epidemic, probabilistic, copy case, spray and wait, and so forth. These techniques achieve an effective routing with minimum latency, higher delivery ratio, lesser overhead, and so forth. Though these techniques generate effective results, in this paper, we propose novel routing algorithms grounded on agent and cryptographic techniques, namely, location dissemination service (LoDiS) routing with agent AES, A-LoDiS with agent AES routing, and B-LoDiS with agent AES routing, ensuring optimal results with respect to various network routing parameters. The algorithm along with efficient routing ensures higher degree of security. The security level is cited testing with respect to possibility of malicious nodes into the network. This paper also aids, with the comparative results of proposed algorithms, for secure routing in ICMANET. PMID:25136697

  19. Adaptation of mobile ad-hoc network protocols for sensor networks to vehicle control applications

    NASA Astrophysics Data System (ADS)

    Sato, Kenya; Matsui, Yosuke; Koita, Takahiro

    2005-12-01

    As sensor network applications to monitor and control the physical environment from remote locations, a mobile ad-hoc network (MANET) has been the focus of many recent research and development efforts. A MANET, autonomous system of mobile hosts, is characterized by multi-hop wireless links, absence of any cellular infrastructure, and frequent host mobility. Many kinds of routing protocols for ad-hoc network have been proposed and still actively updated, because each application has different characteristics and requirements. Since the current studies show it is almost impossible to design an efficient routing protocol to be adapted for all kinds of applications. We, therefore, have focused a certain application, inter-vehicle communication for ITS (Intelligent Transport Systems), to evaluate the routing protocols. In our experiment, we defined several traffic flow models for inter-vehicle communication applications. By using simulation, we evaluated end-to-end delay and throughput performance of data transmission for inter-vehicle communications with the existing routing protocols. The result confirms the feasibility of using some routing protocols for inter-vehicle communication services.

  20. Opportunistic Hybrid Transport Protocol (OHTP) for Cognitive Radio Ad Hoc Sensor Networks.

    PubMed

    Bin Zikria, Yousaf; Nosheen, Summera; Ishmanov, Farruh; Kim, Sung Won

    2015-12-15

    The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, the concept of cognitive radio appeared, which opens up a new research paradigm. There is extensive research on the physical, medium access control and network layers. The impact of the transport layer on the performance of cognitive radio ad hoc sensor networks is still unknown/unexplored. The Internet's de facto transport protocol is not well suited to wireless networks because of its congestion control mechanism. We propose an opportunistic hybrid transport protocol for cognitive radio ad hoc sensor networks. We developed a new congestion control mechanism to differentiate true congestion from interruption loss. After such detection and differentiation, we propose methods to handle them opportunistically. There are several benefits to window- and rate-based protocols. To exploit the benefits of both in order to enhance overall system performance, we propose a hybrid transport protocol. We empirically calculate the optimal threshold value to switch between window- and rate-based mechanisms. We then compare our proposed transport protocol to Transmission Control Protocol (TCP)-friendly rate control, TCP-friendly rate control for cognitive radio, and TCP-friendly window-based control. We ran an extensive set of simulations in Network Simulator 2. The results indicate that the proposed transport protocol performs better than all the others.

  1. Greedy data transportation scheme with hard packet deadlines for wireless ad hoc networks.

    PubMed

    Lee, HyungJune

    2014-01-01

    We present a greedy data transportation scheme with hard packet deadlines in ad hoc sensor networks of stationary nodes and multiple mobile nodes with scheduled trajectory path and arrival time. In the proposed routing strategy, each stationary ad hoc node en route decides whether to relay a shortest-path stationary node toward destination or a passing-by mobile node that will carry closer to destination. We aim to utilize mobile nodes to minimize the total routing cost as far as the selected route can satisfy the end-to-end packet deadline. We evaluate our proposed routing algorithm in terms of routing cost, packet delivery ratio, packet delivery time, and usability of mobile nodes based on network level simulations. Simulation results show that our proposed algorithm fully exploits the remaining time till packet deadline to turn into networking benefits of reducing the overall routing cost and improving packet delivery performance. Also, we demonstrate that the routing scheme guarantees packet delivery with hard deadlines, contributing to QoS improvement in various network services.

  2. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in ad hoc constellations, mission autonomy and

  3. Greedy Data Transportation Scheme with Hard Packet Deadlines for Wireless Ad Hoc Networks

    PubMed Central

    Lee, HyungJune

    2014-01-01

    We present a greedy data transportation scheme with hard packet deadlines in ad hoc sensor networks of stationary nodes and multiple mobile nodes with scheduled trajectory path and arrival time. In the proposed routing strategy, each stationary ad hoc node en route decides whether to relay a shortest-path stationary node toward destination or a passing-by mobile node that will carry closer to destination. We aim to utilize mobile nodes to minimize the total routing cost as far as the selected route can satisfy the end-to-end packet deadline. We evaluate our proposed routing algorithm in terms of routing cost, packet delivery ratio, packet delivery time, and usability of mobile nodes based on network level simulations. Simulation results show that our proposed algorithm fully exploits the remaining time till packet deadline to turn into networking benefits of reducing the overall routing cost and improving packet delivery performance. Also, we demonstrate that the routing scheme guarantees packet delivery with hard deadlines, contributing to QoS improvement in various network services. PMID:25258736

  4. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in ad hoc constellations, mission autonomy and

  5. A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

    PubMed

    Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

  6. Enhancement of Beaconless Location-Based Routing with Signal Strength Assistance for Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    Chen, Guowei; Itoh, Kenichi; Sato, Takuro

    Routing in Ad-hoc networks is unreliable due to the mobility of the nodes. Location-based routing protocols, unlike other protocols which rely on flooding, excel in network scalability. Furthermore, new location-based routing protocols, like, e. g. BLR [1], IGF [2], & CBF [3] have been proposed, with the feature of not requiring beacons in MAC-layer, which improve more in terms of scalability. Such beaconless routing protocols can work efficiently in dense network areas. However, these protocols' algorithms have no ability to avoid from routing into sparse areas. In this article, historical signal strength has been added as a factor into the BLR algorithm, which avoids routing into sparse area, and consequently improves the global routing efficiency.

  7. Energy conservation in ad hoc multimedia networks using traffic-shaping mechanisms

    NASA Astrophysics Data System (ADS)

    Chandra, Surendar

    2003-12-01

    In this work, we explore network traffic shaping mechanisms that deliver packets at pre-determined intervals; allowing the network interface to transition to a lower power consuming sleep state. We focus our efforts on commodity devices, IEEE 802.11b ad hoc mode and popular streaming formats. We argue that factors such as the lack of scheduling clock phase synchronization among the participants and scheduling delays introduced by back ground tasks affect the potential energy savings. Increasing the periodic transmission delays to transmit data infrequently can offset some of these effects at the expense of flooding the wireless channel for longer periods of time; potentially increasing the time to acquire the channel for non-multimedia traffic. Buffering mechanisms built into media browsers can mitigate the effects of these added delays from being mis-interpreted as network congestion. We show that practical implementations of such traffic shaping mechanisms can offer significant energy savings.

  8. Energy-efficient distributed constructions of miniumum spanning tree for wireless ad-hoc networks

    SciTech Connect

    Kumar, V. S. A.; Pandurangan, G.; Khan, M.

    2004-01-01

    The Minimum Spanning Tree (MST) problem is one of the most important and commonly occurring primitive in the design and operation of data and communication networks. While there a redistributed algorithms for the MST problem these require relatively large number of messages and time, and are fairly involved, require synchronization and a lot of book keeping; this makes these algorithms impractical for emerging technologies such as ad hoc and sensor networks. In such networks, a sensor has very limited power, and any algorithm needs to be simple, local and energy efficient for being practical. Motivated by these considerations, we study the performance of a class of simple and local algorithms called Nearest Neighbor Tree (NNT) algorithms for energy-efficient construction of MSTs in a wireless ad hoc setting. These employ a very simple idea to eliminate the work involved in cycle detection in other MST algorithms: each node chooses a distinct rank, and connects to the closest node of higher rank. We consider two variants of the NNT algorithms, obtained by two ways of choosing the ranks: (i) Random NNT, in which each node chooses a rank randomly, and (ii) Directional NNT, in which each node uses directional information for choosing the rank. We show provable bounds on the performance of these algorithms in instances obtained by uniformly distributed points in the unit square. Finally, we perform extensive simulations of our algorithms. We tested our algorithms on both uniformly random distributions of points, and on realistic distributions of points in an urban setting. The cost of the tree found by the NNT algorithms is within a factor of 2 of the MST, but there is more than a ten-fold saving on the energy and about a five fold saving on the number of messages sent. Also, our algorithms are significantly simpler to implement compared to, for instance, the GHS algorithm, which is essentially optimal with regards to the message complexity. Thus, our results

  9. A Family of ACO Routing Protocols for Mobile Ad Hoc Networks

    PubMed Central

    Rupérez Cañas, Delfín; Sandoval Orozco, Ana Lucila; García Villalba, Luis Javier; Kim, Tai-hoon

    2017-01-01

    In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines a reactive route setup process with a proactive route maintenance and improvement process. Key aspects of the AntOR protocol are the disjoint-link and disjoint-node routes, separation between the regular pheromone and the virtual pheromone in the diffusion process and the exploration of routes, taking into consideration the number of hops in the best routes. In this work, a family of ACO routing protocols based on AntOR is also specified. These protocols are based on protocol successive refinements. In this work, we also present a parallelized version of AntOR that we call PAntOR. Using programming multiprocessor architectures based on the shared memory protocol, PAntOR allows running tasks in parallel using threads. This parallelization is applicable in the route setup phase, route local repair process and link failure notification. In addition, a variant of PAntOR that consists of having more than one interface, which we call PAntOR-MI (PAntOR-Multiple Interface), is specified. This approach parallelizes the sending of broadcast messages by interface through threads. PMID:28531159

  10. A Family of ACO Routing Protocols for Mobile Ad Hoc Networks.

    PubMed

    Rupérez Cañas, Delfín; Sandoval Orozco, Ana Lucila; García Villalba, Luis Javier; Kim, Tai-Hoon

    2017-05-22

    In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines a reactive route setup process with a proactive route maintenance and improvement process. Key aspects of the AntOR protocol are the disjoint-link and disjoint-node routes, separation between the regular pheromone and the virtual pheromone in the diffusion process and the exploration of routes, taking into consideration the number of hops in the best routes. In this work, a family of ACO routing protocols based on AntOR is also specified. These protocols are based on protocol successive refinements. In this work, we also present a parallelized version of AntOR that we call PAntOR. Using programming multiprocessor architectures based on the shared memory protocol, PAntOR allows running tasks in parallel using threads. This parallelization is applicable in the route setup phase, route local repair process and link failure notification. In addition, a variant of PAntOR that consists of having more than one interface, which we call PAntOR-MI (PAntOR-Multiple Interface), is specified. This approach parallelizes the sending of broadcast messages by interface through threads.

  11. An Energy-Efficient and Robust Multipath Routing Protocol for Cognitive Radio Ad Hoc Networks.

    PubMed

    Singh, Kishor; Moh, Sangman

    2017-09-04

    Routing in cognitive radio ad hoc networks (CRAHNs) is a daunting task owing to dynamic topology, intermittent connectivity, spectrum heterogeneity, and energy constraints. Other prominent aspects such as channel stability, path reliability, and route discovery frequency should also be exploited. Several routing protocols have been proposed for CRAHNs in the literature. By stressing on one of the aspects more than any other, however, they do not satisfy all requirements of throughput, energy efficiency, and robustness. In this paper, we propose an energy-efficient and robust multipath routing (ERMR) protocol for CRAHNs by considering all prominent aspects including residual energy and channel stability in design. Even when the current routing path fails, the alternative routing path is immediately utilized. In establishing primary and alternative routing paths, both residual energy and channel stability are exploited simultaneously. Our simulation study shows that the proposed ERMR outperforms the conventional protocol in terms of network throughput, packet delivery ratio, energy consumption, and end-to-end delay.

  12. Secure Adaptive Topology Control for Wireless Ad-Hoc Sensor Networks

    PubMed Central

    Hsueh, Ching-Tsung; Li, Yu-Wei; Wen, Chih-Yu; Ouyang, Yen-Chieh

    2010-01-01

    This paper presents a secure decentralized clustering algorithm for wireless ad-hoc sensor networks. The algorithm operates without a centralized controller, operates asynchronously, and does not require that the location of the sensors be known a priori. Based on the cluster-based topology, secure hierarchical communication protocols and dynamic quarantine strategies are introduced to defend against spam attacks, since this type of attacks can exhaust the energy of sensor nodes and will shorten the lifetime of a sensor network drastically. By adjusting the threshold of infected percentage of the cluster coverage, our scheme can dynamically coordinate the proportion of the quarantine region and adaptively achieve the cluster control and the neighborhood control of attacks. Simulation results show that the proposed approach is feasible and cost effective for wireless sensor networks. PMID:22205866

  13. Analysis of a distributed algorithm to determine multiple routes with path diversity in ad hoc networks.

    SciTech Connect

    Ghosal, Dipak; Mueller, Stephen Ng

    2005-04-01

    With multipath routing in mobile ad hoc networks (MANETs), a source can establish multiple routes to a destination for routing data. In MANETs, mulitpath routing can be used to provide route resilience, smaller end-to-end delay, and better load balancing. However, when the multiple paths are close together, transmissions of different paths may interfere with each other, causing degradation in performance. Besides interference, the physical diversity of paths also improves fault tolerance. We present a purely distributed multipath protocol based on the AODV-Multipath (AODVM) protocol called AODVM with Path Diversity (AODVM/PD) that finds multiple paths with a desired degree of correlation between paths specified as an input parameter to the algorithm. We demonstrate through detailed simulation analysis that multiple paths with low degree of correlation determined by AODVM/PD provides both smaller end-to-end delay than AODVM in networks with low mobility and better route resilience in the presence of correlated node failures.

  14. A distributed intelligent information system with natural language input for ad hoc knowledge discovery in databases

    SciTech Connect

    Fass, D.; Hall, G.; Laurens, O.; McFetridge, P.; Popowich, F.; Rueden, M. von

    1996-11-01

    A distributed information system is described which features a graphic user interface incorporating natural language input and which provides ad hoc knowledge discovery in relational databases. The system is comprised of multiple processes which communicate with each other over a network. The knowledge discovery process involves extracting generalizations from data using background knowledge in the form of concept hierarchies and a learning procedure based upon an attribute-oriented induction technique. The natural language understanding process is a parser based on Head-Driven Phrase Structure Grammar (HPSG), a modern lexicon-based grammar formalism better equipped than older rule-based approaches for handling the often idiosyncratic behavior of words. To generate semantic interpretations, the parser makes use of a process which orders logical access paths in unnormalized databases based on the strength of their dependency structures and on their efficiency of execution.

  15. A high performance, ad-hoc, fuzzy query processing system for relational databases

    NASA Technical Reports Server (NTRS)

    Mansfield, William H., Jr.; Fleischman, Robert M.

    1992-01-01

    Database queries involving imprecise or fuzzy predicates are currently an evolving area of academic and industrial research. Such queries place severe stress on the indexing and I/O subsystems of conventional database environments since they involve the search of large numbers of records. The Datacycle architecture and research prototype is a database environment that uses filtering technology to perform an efficient, exhaustive search of an entire database. It has recently been modified to include fuzzy predicates in its query processing. The approach obviates the need for complex index structures, provides unlimited query throughput, permits the use of ad-hoc fuzzy membership functions, and provides a deterministic response time largely independent of query complexity and load. This paper describes the Datacycle prototype implementation of fuzzy queries and some recent performance results.

  16. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks

    PubMed Central

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-01-01

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes. PMID:26184224

  17. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks.

    PubMed

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-07-14

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes.

  18. Performance optimisation through EPT-WBC in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Agarwal, Ratish; Gupta, Roopam; Motwani, Mahesh

    2016-03-01

    Mobile ad hoc networks are self-organised, infrastructure-less networks in which each mobile host works as a router to provide connectivity within the network. Nodes out of reach to each other can communicate with the help of intermediate routers (nodes). Routing protocols are the rules which determine the way in which these routing activities are to be performed. In cluster-based architecture, some selected nodes (clusterheads) are identified to bear the extra burden of network activities like routing. Selection of clusterheads is a critical issue which significantly affects the performance of the network. This paper proposes an enhanced performance and trusted weight-based clustering approach in which a number of performance factors such as trust, load balancing, energy consumption, mobility and battery power are considered for the selection of clusterheads. Moreover, the performance of the proposed scheme is compared with other existing approaches to demonstrate the effectiveness of the work.

  19. A high performance, ad-hoc, fuzzy query processing system for relational databases

    NASA Technical Reports Server (NTRS)

    Mansfield, William H., Jr.; Fleischman, Robert M.

    1992-01-01

    Database queries involving imprecise or fuzzy predicates are currently an evolving area of academic and industrial research. Such queries place severe stress on the indexing and I/O subsystems of conventional database environments since they involve the search of large numbers of records. The Datacycle architecture and research prototype is a database environment that uses filtering technology to perform an efficient, exhaustive search of an entire database. It has recently been modified to include fuzzy predicates in its query processing. The approach obviates the need for complex index structures, provides unlimited query throughput, permits the use of ad-hoc fuzzy membership functions, and provides a deterministic response time largely independent of query complexity and load. This paper describes the Datacycle prototype implementation of fuzzy queries and some recent performance results.

  20. Robotic disaster recovery efforts with ad-hoc deployable cloud computing

    NASA Astrophysics Data System (ADS)

    Straub, Jeremy; Marsh, Ronald; Mohammad, Atif F.

    2013-06-01

    Autonomous operations of search and rescue (SaR) robots is an ill posed problem, which is complexified by the dynamic disaster recovery environment. In a typical SaR response scenario, responder robots will require different levels of processing capabilities during various parts of the response effort and will need to utilize multiple algorithms. Placing these capabilities onboard the robot is a mediocre solution that precludes algorithm specific performance optimization and results in mediocre performance. Architecture for an ad-hoc, deployable cloud environment suitable for use in a disaster response scenario is presented. Under this model, each service provider is optimized for the task and maintains a database of situation-relevant information. This service-oriented architecture (SOA 3.0) compliant framework also serves as an example of the efficient use of SOA 3.0 in an actual cloud application.

  1. EPCM - an efficient power controlled MAC protocol for mobile ad hoc network

    NASA Astrophysics Data System (ADS)

    Seth, D. D.; Patnaik, S.; Pal, S.

    2014-10-01

    To reduce interference and to save a significant amount of energy, a control of transmission power is employed in Mobile Ad hoc Network. Many researchers have reported numerous transmission power control schemes to achieve the objective. Some of those techniques use higher transmission power for control packets (Request To Send/Clear To Send) and lesser power for Data and ACK packets. These schemes, though save some amount of energy, achieve least aggregate throughput due to poor spatial reuse and hidden terminal interference. In this paper, an efficient Power Controlled Medium Access Control (EPCM) scheme is evinced, which uses uniform interference aware and minimum transmission power for both Control and Data packet. The performance of EPCM is evaluated and compared with three reported Medium Access Control protocols which are based on transmission power control schemes and is observed that the proposed protocol achieves better throughput and minimal energy consumption while avoiding the hidden terminal problem.

  2. Performance Analysis of Ad Hoc Routing Protocols in City Scenario for VANET

    NASA Astrophysics Data System (ADS)

    Das, Sanjoy; Raw, Ram Shringar; Das, Indrani

    2011-12-01

    In this paper, performance analysis of Location Aided Routing (LAR), AODV and DSR protocol in city scenarios has been done. The mobility model considered is Manhattan model. This mobility model used to emulate the movement pattern of nodes i.e., vehicles on streets defined by maps. Our objective is to provide a comparative analysis among LAR, AODV and DSR protocol in city scenarios in Vehicular Ad hoc Networks. The simulation work has been conducted using the Glomosim 2.03 simulator. The results show that LAR1 protocol achieves maximum packet delivery ratio is 100% in the sparsely populated network. The delay is maximum in AODV 121.88 ms when the number of node is 10 in the network. The results show that LAR1 outperform DSR and AODV in term of packet delivery ratio and end to end delay.

  3. Topology Control in Large-Scale High Dynamic Mobile Ad-Hoc Networks

    NASA Astrophysics Data System (ADS)

    El-Habbal, Mohamed; Rückert, Ulrich; Witkowski, Ulf

    We present our contribution in projects related to ad-hoc networking using different routing protocols and hardware platforms, showing our results and new solutions regarding topology control and routing protocols. We mainly focus on our work in the GUARDIANS EU-project, where as a main disaster scenario a large industrial warehouse on fire is assumed. The paper presents the simulation results for the routing protocols ACR, DSR and EDSR, as well as the implementation of down-scaled demos for supporting the autonomous team of robots as well as the human squad team with robust communication coverage. Various hardware platforms were used in the demos for distance measurement, based on laser range finder and radio communication with time of flight analysis.

  4. Noise-Assisted Concurrent Multipath Traffic Distribution in Ad Hoc Networks

    PubMed Central

    Murata, Masayuki

    2013-01-01

    The concept of biologically inspired networking has been introduced to tackle unpredictable and unstable situations in computer networks, especially in wireless ad hoc networks where network conditions are continuously changing, resulting in the need of robustness and adaptability of control methods. Unfortunately, existing methods often rely heavily on the detailed knowledge of each network component and the preconfigured, that is, fine-tuned, parameters. In this paper, we utilize a new concept, called attractor perturbation (AP), which enables controlling the network performance using only end-to-end information. Based on AP, we propose a concurrent multipath traffic distribution method, which aims at lowering the average end-to-end delay by only adjusting the transmission rate on each path. We demonstrate through simulations that, by utilizing the attractor perturbation relationship, the proposed method achieves a lower average end-to-end delay compared to other methods which do not take fluctuations into account. PMID:24319375

  5. A Hybrid Visual Dataflow Language for Coordination in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Lombide Carreton, Andoni; D'Hondt, Theo

    Because of the dynamic nature of mobile ad hoc networks and the applications running on top of them, these applications have to be conceived as event-driven architectures. Such architectures are hard to program because coordination between concurrent and distributed mobile components has to be expressed by means of event handlers or callbacks. Applications consisting of disjoint event handlers that are independently triggered (possibly by their environment) exhibit a very implicit control flow that is hard to grasp. This paper presents a visual dataflow language tailored towards mobile applications to express the interaction between mobile components that operate on data streams. By using a visual dataflow language as a separate coordination language, the coarse grained control flow of a mobile application can be specified visually and separately from the fine grained control flow. In its turn, this allows a very explicit view on the control flow of the entire mobile application.

  6. Impact of Beamforming on the Path Connectivity in Cognitive Radio Ad Hoc Networks

    PubMed Central

    Dung, Le The; Hieu, Tran Dinh; Choi, Seong-Gon; Kim, Byung-Seo; An, Beongku

    2017-01-01

    This paper investigates the impact of using directional antennas and beamforming schemes on the connectivity of cognitive radio ad hoc networks (CRAHNs). Specifically, considering that secondary users use two kinds of directional antennas, i.e., uniform linear array (ULA) and uniform circular array (UCA) antennas, and two different beamforming schemes, i.e., randomized beamforming and center-directed to communicate with each other, we study the connectivity of all combination pairs of directional antennas and beamforming schemes and compare their performances to those of omnidirectional antennas. The results obtained in this paper show that, compared with omnidirectional transmission, beamforming transmission only benefits the connectivity when the density of secondary user is moderate. Moreover, the combination of UCA and randomized beamforming scheme gives the highest path connectivity in all evaluating scenarios. Finally, the number of antenna elements and degree of path loss greatly affect path connectivity in CRAHNs. PMID:28346377

  7. A Leasing Model to Deal with Partial Failures in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Gonzalez Boix, Elisa; van Cutsem, Tom; Vallejos, Jorge; de Meuter, Wolfgang; D'Hondt, Theo

    In mobile ad hoc networks (MANETs) many partial failures are the result of temporary network partitions due to the intermittent connectivity of mobile devices. Some of these failures will be permanent and require application-level failure handling. However, it is impossible to distinguish a permanent from a transient failure. Leasing provides a solution to this problem based on the temporal restriction of resources. But to date no leasing model has been designed specifically for MANETs. In this paper, we identify three characteristics required for a leasing model to be usable in a MANET, discuss the issues with existing leasing models and then propose the leased object references model, which integrates leasing with remote object references. In addition, we describe an implementation of the model in the programming language AmbientTalk. Leased object references provide an extensible framework that allows programmers to express their own leasing patterns and enables both lease holders (clients) and lease grantors (services) to deal with permanent failures.

  8. Data Extraction and Ad Hoc Query of an Entity— Attribute— Value Database

    PubMed Central

    Nadkarni, Prakash M.; Brandt, Cynthia

    1998-01-01

    Entity—attribute—value (EAV) tables form the major component of several mainstream electronic patient record systems (EPRSs). Such systems have been optimized for real-time retrieval of individual patient data. Data warehousing, on the other hand, involves cross-patient data retrieval based on values of patient attributes, with a focus on ad hoc query. Attribute-centric query is inherently more difficult when data are stored in EAV form than when they are stored conventionally. The authors illustrate their approach to the attribute-centric query problem with ACT/DB, a database for managing clinical trials data. This approach is based on metadata supporting a query front end that essentially hides the EAV/non-EAV nature of individual attributes from the user. The authors' work does not close the query problem, and they identify several complex subproblems that are still to be solved. PMID:9824799

  9. Effective Route Maintenance and Restoration Schemes in Mobile Ad Hoc Networks

    PubMed Central

    Kang, Byung-Seok; Ko, In-Young

    2010-01-01

    This study proposes a location-based hybrid routing protocol to improve data packet delivery and to reduce control message overhead in mobile ad hoc networks. In mobile environments, where nodes move continuously at a high speed, it is generally difficult to maintain and restore route paths. Therefore, this study suggests a new flooding mechanism to control route paths. The essence of the proposed scheme is its effective tracking of the destination’s location based on the beacon messages of the main route nodes. Through experiments based on an NS-2 simulator, the proposed scheme shows improvements in the data packet delivery ratio and reduces the amount of routing control message overhead compared with existing routing protocols such as AODV, LAR, ZRP and AODV-DFR. PMID:22315570

  10. A time-slotted on-demand routing protocol for mobile ad hoc unmanned vehicle systems

    NASA Astrophysics Data System (ADS)

    Forsmann, J. Hope; Hiromoto, Robert E.; Svoboda, John

    2007-04-01

    Successful deployment of Unmanned Vehicle Systems (UVS) in military operations has increased their popularity and utility. The ability to sustain reliable mobile ad hoc formations dramatically enhances the usefulness and performance of UVS. Formation movement increases the amount of ground coverage in less time, decreases fuel consumption of the individual nodes, and provides an avenue for mission expansion through cooperative maneuvers such as refueling. In this paper, we study the wireless communication demands that arise from formation and maintenance of UVS within the context of a mobile ad hoc network (MANET). A MANET in formation is typically characterized by tradeoffs between network congestion and the ability to maintain useable communication bandwidth. Maintenance of UVS formations requires each node in the network to be peer-aware, which places a heavy demand on inner node communication. In order to mitigate the inner node network congestion, we introduce a time-slotted communication protocol. The protocol assigns time-slots and allows the designated nodes to communicate directly with other peer-nodes. This approach has been introduced within the context of the Time-Slotted Aloha protocol for station-to-station communication. The approach taken here is to embed the time-slotted reservation protocol into a standard on-demand routing protocol to also address the need to reactively and proactively respond to formation maintenance. The time-slotted on-demand routing protocol is shown to eliminate collisions due to route determination and, therefore, enhance quality of service as well as ensure necessary support for formation movement. A worst-case scenario is described and simulations performed to comparatively demonstrate the advantages of the new protocol.

  11. Opportunistic Hybrid Transport Protocol (OHTP) for Cognitive Radio Ad Hoc Sensor Networks

    PubMed Central

    Zikria, Yousaf Bin; Nosheen, Summera; Ishmanov, Farruh; Kim, Sung Won

    2015-01-01

    The inefficient assignment of spectrum for different communications purposes, plus technology enhancements and ever-increasing usage of wireless technology is causing spectrum scarcity. To address this issue, one of the proposed solutions in the literature is to access the spectrum dynamically or opportunistically. Therefore, the concept of cognitive radio appeared, which opens up a new research paradigm. There is extensive research on the physical, medium access control and network layers. The impact of the transport layer on the performance of cognitive radio ad hoc sensor networks is still unknown/unexplored. The Internet’s de facto transport protocol is not well suited to wireless networks because of its congestion control mechanism. We propose an opportunistic hybrid transport protocol for cognitive radio ad hoc sensor networks. We developed a new congestion control mechanism to differentiate true congestion from interruption loss. After such detection and differentiation, we propose methods to handle them opportunistically. There are several benefits to window- and rate-based protocols. To exploit the benefits of both in order to enhance overall system performance, we propose a hybrid transport protocol. We empirically calculate the optimal threshold value to switch between window- and rate-based mechanisms. We then compare our proposed transport protocol to Transmission Control Protocol (TCP)-friendly rate control, TCP-friendly rate control for cognitive radio, and TCP-friendly window-based control. We ran an extensive set of simulations in Network Simulator 2. The results indicate that the proposed transport protocol performs better than all the others. PMID:26694396

  12. Integrated data lookup and replication scheme in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Chen, Kai; Nahrstedt, Klara

    2001-11-01

    Accessing remote data is a challenging task in mobile ad hoc networks. Two problems have to be solved: (1) how to learn about available data in the network; and (2) how to access desired data even when the original copy of the data is unreachable. In this paper, we develop an integrated data lookup and replication scheme to solve these problems. In our scheme, a group of mobile nodes collectively host a set of data to improve data accessibility for all members of the group. They exchange data availability information by broadcasting advertising (ad) messages to the group using an adaptive sending rate policy. The ad messages are used by other nodes to derive a local data lookup table, and to reduce data redundancy within a connected group. Our data replication scheme predicts group partitioning based on each node's current location and movement patterns, and replicates data to other partitions before partitioning occurs. Our simulations show that data availability information can quickly propagate throughout the network, and that the successful data access ratio of each node is significantly improved.

  13. Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

    DOE PAGES

    Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

    2015-09-29

    In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At themore » core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified

  14. Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

    SciTech Connect

    Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

    2015-09-29

    In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At the core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified application

  15. Characterizing the Interaction Between Routing and MAC Protocols in Ad-Hoc Networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, A.; Marathe, M. V.

    2002-01-01

    We empirically study the effect of mobility on the performance of protocols designed for wireless ad-hoc networks. An important objective is to study the interaction of the Routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols is measured in terms of (i) latency, (ii) throughput, (iii) number of packets received, (iv) long term fairness and (v) number of control packets at the MAC and routing layer level. Three different commonly studied routing protocols are used: AODV, DSR and LAR1. Similarly three well known MAC protocols are used: MACA, 802.1 1 and CSMA. Our main contribution is simulation based experiments coupled with rigorous statistical analysis to characterize the interaction of MAC layer protocols with routing layer protocols in ad-hoc networks. From the results, we can conclude the following: e No single MAC or Routing protocol dominated the other protocols in their class. Probably more interestingly, no MAURouting protocol combination was better than other combinations over all scenarios and response variables. 0 In general, it is not meaningful to speak about a MAC or a routing protocol in isolation. Presence of interaction leads to trade-offs between the amount of control packets generated by each layer. The results raise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa. Thus in order to improve the performanceof a communication network, it is important to study the entire protocol stack as a single algorithmic construct; optimizing individual layers in the seven layer OS1 stack will not yield performance improvements beyond a point. A methodological contribution of this paper is the use of statistical methods such as analysis of variance (ANOVA), to characterize the interaction between the protocols

  16. How Gas-dynamic Flare Models Powered by Petschek Reconnection Differ from Those with Ad Hoc Energy Sources

    NASA Astrophysics Data System (ADS)

    Longcope, D. W.; Klimchuk, J. A.

    2015-11-01

    Aspects of solar flare dynamics, such as chromospheric evaporation and flare light curves, have long been studied using one-dimensional models of plasma dynamics inside a static flare loop, subjected to some energy input. While extremely successful at explaining the observed characteristics of flares, all such models so far have specified energy input ad hoc, rather than deriving it self-consistently. There is broad consensus that flares are powered by magnetic energy released through reconnection. Recent work has generalized Petschek’s basic reconnection scenario, topological change followed by field line retraction and shock heating, to permit its inclusion in a one-dimensional flare loop model. Here we compare the gas dynamics driven by retraction and shocking to those from more conventional static loop models energized by ad hoc source terms. We find significant differences during the first minute, when retraction leads to larger kinetic energies and produces higher densities at the loop top, while ad hoc heating tends to rarify the loop top. The loop-top density concentration is related to the slow magnetosonic shock, characteristic of Petschek’s model, but persists beyond the retraction phase occurring in the outflow jet. This offers an explanation for observed loop-top sources of X-ray and EUV emission, with advantages over that provided by ad hoc heating scenarios. The cooling phases of the two models are, however, notably similar to one another, suggesting that observations at that stage will yield little information on the nature of energy input.

  17. The Impact of Using Item Parcels on ad hoc Goodness of Fit Indices in Confirmatory Factor Analysis: An Empirical Example.

    ERIC Educational Resources Information Center

    Takahashi, Tomone; Nasser, Fadia

    The Arabic version of I. G. Sarason's (1984) Reactions to Tests scale was used to examine the impact of using item parcels on ad hoc goodness of fit indices in confirmatory factor analysis. Item parcels with different numbers of items and different numbers of parcels per factor were used. Analyses were conducted on a sample of 420 tenth graders…

  18. Managing daily intensive care activities: An observational study concerning ad hoc decision making of charge nurses and intensivists

    PubMed Central

    2011-01-01

    Introduction Management of daily activities in ICUs is challenging. ICU shift leaders, charge nurses and intensivists have to make several immediate ad hoc decisions to enable the fluent flow of ICU activities. Even though the management of ICU activities is quite well delineated by international consensus guidelines, we know only a little about the content of the real clinical decision making of ICU shift leaders. Methods We conducted an observational study with the think-aloud technique to describe the ad hoc decision making of ICU shift leaders. The study was performed in two university-affiliated hospital ICUs. Twelve charge nurses and eight intensivists were recruited. Observations were recorded and transcribed for qualitative content analysis using the protocol analysis method. The software program NVivo 7 was used to manage the data. The interrater agreement was assessed with percentages and by Cohen's κ. Results We identified 463 ad hoc decisions made by the charge nurses and 444 made by the intensivists. During our data collection time, this breaks down to over 230 immediately made decisions per day (24 hours). We divided the ad hoc decision making of ICU shift leaders into two types: process-focused and situation-focused. Process-focused decision making included more permanent information, such as human resources, know-how and material resources, whereas situation-focused decision making included decisions about single events, such as patient admission. We named eight different categories for ICU ad hoc decision making: (1) adverse events, (2) diagnostics, (3) human resources and know-how, (4) material resources, (5) patient admission, (6) patient discharge, (7) patient information and vital signs and (8) special treatments. Conclusions ICU shift leaders make a great number of complex ad hoc decisions throughout the day. Often this decision making involves both intensivists and charge nurses. It forms a bundle that requires versatile, immediate

  19. Sketching Awareness: A Participatory Study to Elicit Designs for Supporting Ad Hoc Emergency Medical Teamwork

    PubMed Central

    Kusunoki, Diana; Sarcevic, Aleksandra; Zhang, Zhan; Yala, Maria

    2014-01-01

    Prior CSCW research on awareness in clinical settings has mostly focused on higher-level team coordination spanning across longer-term trajectories at the department and inter-department levels. In this paper, we offer a perspective on what awareness means within the context of an ad hoc, time- and safety-critical medical setting by looking at teams treating severely ill patients with urgent needs. We report findings from four participatory design workshops conducted with emergency medicine clinicians at two regional emergency departments. Workshops were developed to elicit design ideas for information displays that support awareness in emergency medical situations. Through analysis of discussions and clinicians’ sketches of information displays, we identified five features of teamwork that can be used as a foundation for supporting awareness from the perspective of clinicians. Based on these findings, we contribute rich descriptions of four facets of awareness that teams manage during emergency medical situations: team member awareness, elapsed time awareness, teamwork-oriented and patient-driven task awareness, and overall progress awareness. We then discuss these four awareness types in relation to awareness facets found in the CSCW literature. PMID:25870498

  20. Secure and fair cluster head selection protocol for enhancing security in mobile ad hoc networks.

    PubMed

    Paramasivan, B; Kaliappan, M

    2014-01-01

    Mobile ad hoc networks (MANETs) are wireless networks consisting of number of autonomous mobile devices temporarily interconnected into a network by wireless media. MANETs become one of the most prevalent areas of research in the recent years. Resource limitations, energy efficiency, scalability, and security are the great challenging issues in MANETs. Due to its deployment nature, MANETs are more vulnerable to malicious attack. The secure routing protocols perform very basic security related functions which are not sufficient to protect the network. In this paper, a secure and fair cluster head selection protocol (SFCP) is proposed which integrates security factors into the clustering approach for achieving attacker identification and classification. Byzantine agreement based cooperative technique is used for attacker identification and classification to make the network more attack resistant. SFCP used to solve this issue by making the nodes that are totally surrounded by malicious neighbors adjust dynamically their belief and disbelief thresholds. The proposed protocol selects the secure and energy efficient cluster head which acts as a local detector without imposing overhead to the clustering performance. SFCP is simulated in network simulator 2 and compared with two protocols including AODV and CBRP.

  1. Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety

    PubMed Central

    Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

    2016-01-01

    The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels. PMID:26784204

  2. The congestion control algorithm based on queue management of each node in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Wei, Yifei; Chang, Lin; Wang, Yali; Wang, Gaoping

    2016-12-01

    This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. As the network load increases, local congestion of mobile ad hoc network may lead to network performance degradation, hot node's energy consumption increase even failure. If small energy nodes congested because of forwarding data packets, then when it is used as the source node will cause a lot of packet loss. This paper proposes an active queue management mechanism, considering the node's own ability and its importance in the network to set the queue threshold. Controlling nodes buffer queue in different levels of congestion area probability by adjusting the upper limits and lower limits, thus nodes can adjust responsibility of forwarding data packets according to their own situation. The proposed algorithm will slow down the send rate hop by hop along the data package transmission direction from congestion node to source node so that to prevent further congestion from the source node. The simulation results show that, the algorithm can better play the data forwarding ability of strong nodes, protect the weak nodes, can effectively alleviate the network congestion situation.

  3. An Energy-Efficient and Robust Multipath Routing Protocol for Cognitive Radio Ad Hoc Networks

    PubMed Central

    Singh, Kishor

    2017-01-01

    Routing in cognitive radio ad hoc networks (CRAHNs) is a daunting task owing to dynamic topology, intermittent connectivity, spectrum heterogeneity, and energy constraints. Other prominent aspects such as channel stability, path reliability, and route discovery frequency should also be exploited. Several routing protocols have been proposed for CRAHNs in the literature. By stressing on one of the aspects more than any other, however, they do not satisfy all requirements of throughput, energy efficiency, and robustness. In this paper, we propose an energy-efficient and robust multipath routing (ERMR) protocol for CRAHNs by considering all prominent aspects including residual energy and channel stability in design. Even when the current routing path fails, the alternative routing path is immediately utilized. In establishing primary and alternative routing paths, both residual energy and channel stability are exploited simultaneously. Our simulation study shows that the proposed ERMR outperforms the conventional protocol in terms of network throughput, packet delivery ratio, energy consumption, and end-to-end delay. PMID:28869551

  4. Standardization of Negative Controls in Diagnostic Immunohistochemistry: Recommendations From the International Ad Hoc Expert Panel

    PubMed Central

    Torlakovic, Emina E.; Francis, Glenn; Garratt, John; Gilks, Blake; Hyjek, Elizabeth; Ibrahim, Merdol; Miller, Rodney; Nielsen, Søren; Petcu, Eugen B.; Swanson, Paul E.; Taylor, Clive R.; Vyberg, Mogens

    2014-01-01

    Standardization of controls, both positive and negative controls, is needed for diagnostic immunohistochemistry (dIHC). The use of IHC-negative controls, irrespective of type, although well established, is not standardized. As such, the relevance and applicability of negative controls continues to challenge both pathologists and laboratory budgets. Despite the clear theoretical notion that appropriate controls serve to demonstrate the sensitivity and specificity of the dIHC test, it remains unclear which types of positive and negative controls are applicable and/or useful in day-to-day clinical practice. There is a perceived need to provide “best practice recommendations” for the use of negative controls. This perception is driven not only by logistics and cost issues, but also by increased pressure for accurate IHC testing, especially when IHC is performed for predictive markers, the number of which is rising as personalized medicine continues to develop. Herein, an international ad hoc expert panel reviews classification of negative controls relevant to clinical practice, proposes standard terminology for negative controls, considers the total evidence of IHC specificity that is available to pathologists, and develops a set of recommendations for the use of negative controls in dIHC based on “fit-for-use” principles. PMID:24714041

  5. Ad Hoc modeling, expert problem solving, and R&T program evaluation

    NASA Technical Reports Server (NTRS)

    Silverman, B. G.; Liebowitz, J.; Moustakis, V. S.

    1983-01-01

    A simplified cost and time (SCAT) analysis program utilizing personal-computer technology is presented and demonstrated in the case of the NASA-Goddard end-to-end data system. The difficulties encountered in implementing complex program-selection and evaluation models in the research and technology field are outlined. The prototype SCAT system described here is designed to allow user-friendly ad hoc modeling in real time and at low cost. A worksheet constructed on the computer screen displays the critical parameters and shows how each is affected when one is altered experimentally. In the NASA case, satellite data-output and control requirements, ground-facility data-handling capabilities, and project priorities are intricately interrelated. Scenario studies of the effects of spacecraft phaseout or new spacecraft on throughput and delay parameters are shown. The use of a network of personal computers for higher-level coordination of decision-making processes is suggested, as a complement or alternative to complex large-scale modeling.

  6. Ad Hoc modeling, expert problem solving, and R&T program evaluation

    NASA Technical Reports Server (NTRS)

    Silverman, B. G.; Liebowitz, J.; Moustakis, V. S.

    1983-01-01

    A simplified cost and time (SCAT) analysis program utilizing personal-computer technology is presented and demonstrated in the case of the NASA-Goddard end-to-end data system. The difficulties encountered in implementing complex program-selection and evaluation models in the research and technology field are outlined. The prototype SCAT system described here is designed to allow user-friendly ad hoc modeling in real time and at low cost. A worksheet constructed on the computer screen displays the critical parameters and shows how each is affected when one is altered experimentally. In the NASA case, satellite data-output and control requirements, ground-facility data-handling capabilities, and project priorities are intricately interrelated. Scenario studies of the effects of spacecraft phaseout or new spacecraft on throughput and delay parameters are shown. The use of a network of personal computers for higher-level coordination of decision-making processes is suggested, as a complement or alternative to complex large-scale modeling.

  7. A Threshold-Adaptive Reputation System on Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsai, Hsiao-Chien; Lo, Nai-Wei; Wu, Tzong-Chen

    In recent years huge potential benefits from novel applications in mobile ad hoc networks (MANET) have been discussed extensively. However, without robust security mechanisms and systems to provide safety shell through the MANET infrastructure, MANET applications can be vulnerable and hammered by malicious attackers easily. In order to detect misbehaved message routing and identify malicious attackers in MANET, schemes based on reputation concept have shown their advantages in this area in terms of good scalability and simple threshold-based detection strategy. We observed that previous reputation schemes generally use predefined thresholds which do not take into account the effect of behavior dynamics between nodes in a period of time. In this paper, we propose a Threshold-Adaptive Reputation System (TARS) to overcome the shortcomings of static threshold strategy and improve the overall MANET performance under misbehaved routing attack. A fuzzy-based inference engine is introduced to evaluate the trustiness of a node's one-hop neighbors. Malicious nodes whose trust values are lower than the adaptive threshold, will be detected and filtered out by their honest neighbors during trustiness evaluation process. The results of network simulation show that the TARS outperforms other compared schemes under security attacks in most cases and at the same time reduces the decrease of total packet delivery ratio by 67% in comparison with MANET without reputation system.

  8. A DNA-Inspired Encryption Methodology for Secure, Mobile Ad Hoc Networks

    NASA Technical Reports Server (NTRS)

    Shaw, Harry

    2012-01-01

    Users are pushing for greater physical mobility with their network and Internet access. Mobile ad hoc networks (MANET) can provide an efficient mobile network architecture, but security is a key concern. A figure summarizes differences in the state of network security for MANET and fixed networks. MANETs require the ability to distinguish trusted peers, and tolerate the ingress/egress of nodes on an unscheduled basis. Because the networks by their very nature are mobile and self-organizing, use of a Public Key Infra structure (PKI), X.509 certificates, RSA, and nonce ex changes becomes problematic if the ideal of MANET is to be achieved. Molecular biology models such as DNA evolution can provide a basis for a proprietary security architecture that achieves high degrees of diffusion and confusion, and resistance to cryptanalysis. A proprietary encryption mechanism was developed that uses the principles of DNA replication and steganography (hidden word cryptography) for confidentiality and authentication. The foundation of the approach includes organization of coded words and messages using base pairs organized into genes, an expandable genome consisting of DNA-based chromosome keys, and a DNA-based message encoding, replication, and evolution and fitness. In evolutionary computing, a fitness algorithm determines whether candidate solutions, in this case encrypted messages, are sufficiently encrypted to be transmitted. The technology provides a mechanism for confidential electronic traffic over a MANET without a PKI for authenticating users.

  9. Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety.

    PubMed

    Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

    2016-01-15

    The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels.

  10. Linking satellites via Earth hot spots and the Internet to form ad hoc constellations

    NASA Astrophysics Data System (ADS)

    Mandl, Daniel; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix A.; Lee, Richard Q.; Romanofsky, Robert R.; Zaman, Afroz; Popovic, Zoya; Sherwood, Robert L.; Chien, Steve; Davies, Ashley

    2005-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet, the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in the area of adaptive antenna arrays and some of the related successful autonomy software that has been implemented using EO-1 and other operational satellites.

  11. Delay-dependent asymptotic stability of mobile ad-hoc networks: A descriptor system approach

    NASA Astrophysics Data System (ADS)

    Yang, Juan; Yang, Dan; Huang, Bin; Zhang, Xiao-Hong; Luo, Jian-Lu

    2014-07-01

    In order to analyze the capacity stability of the time-varying-propagation and delay-dependent of mobile ad-hoc networks (MANETs), in this paper, a novel approach is proposed to explore the capacity asymptotic stability for the delay-dependent of MANETs based on non-cooperative game theory, where the delay-dependent conditions are explicitly taken into consideration. This approach is based on the Lyapunov—Krasovskii stability theory for functional differential equations and the linear matrix inequality (LMI) technique. A corresponding Lyapunov—Krasovskii functional is introduced for the stability analysis of this system with use of the descriptor and “neutral-type” model transformation without producing any additional dynamics. The delay-dependent stability criteria are derived for this system. Conditions are given in terms of linear matrix inequalities, and for the first time referred to neutral systems with the time-varying propagation and delay-dependent stability for capacity analysis of MANETs. The proposed criteria are less conservative since they are based on an equivalent model transformation. Furthermore, we also provide an effective and efficient iterative algorithm to solve the constrained stability control model. Simulation experiments have verified the effectiveness and efficiency of our algorithm.

  12. Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks.

    PubMed

    Katiravan, Jeevaa; Sylvia, D; Rao, D Srinivasa

    2015-01-01

    In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network.

  13. Energy-efficient algorithm for broadcasting in ad hoc wireless sensor networks.

    PubMed

    Xiong, Naixue; Huang, Xingbo; Cheng, Hongju; Wan, Zheng

    2013-04-12

    Broadcasting is a common and basic operation used to support various network protocols in wireless networks. To achieve energy-efficient broadcasting is especially important for ad hoc wireless sensor networks because sensors are generally powered by batteries with limited lifetimes. Energy consumption for broadcast operations can be reduced by minimizing the number of relay nodes based on the observation that data transmission processes consume more energy than data reception processes in the sensor nodes, and how to improve the network lifetime is always an interesting issue in sensor network research. The minimum-energy broadcast problem is then equivalent to the problem of finding the minimum Connected Dominating Set (CDS) for a connected graph that is proved NP-complete. In this paper, we introduce an Efficient Minimum CDS algorithm (EMCDS) with help of a proposed ordered sequence list. EMCDS does not concern itself with node energy and broadcast operations might fail if relay nodes are out of energy. Next we have proposed a Minimum Energy-consumption Broadcast Scheme (MEBS) with a modified version of EMCDS, and aimed at providing an efficient scheduling scheme with maximized network lifetime. The simulation results show that the proposed EMCDS algorithm can find smaller CDS compared with related works, and the MEBS can help to increase the network lifetime by efficiently balancing energy among nodes in the networks.

  14. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey.

    PubMed

    Zareei, Mahdi; Islam, A K M Muzahidul; Baharun, Sabariah; Vargas-Rosales, Cesar; Azpilicueta, Leyre; Mansoor, Nafees

    2017-09-16

    New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR) and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC) protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN). First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective.

  15. A Game Theory Algorithm for Intra-Cluster Data Aggregation in a Vehicular Ad Hoc Network.

    PubMed

    Chen, Yuzhong; Weng, Shining; Guo, Wenzhong; Xiong, Naixue

    2016-02-19

    Vehicular ad hoc networks (VANETs) have an important role in urban management and planning. The effective integration of vehicle information in VANETs is critical to traffic analysis, large-scale vehicle route planning and intelligent transportation scheduling. However, given the limitations in the precision of the output information of a single sensor and the difficulty of information sharing among various sensors in a highly dynamic VANET, effectively performing data aggregation in VANETs remains a challenge. Moreover, current studies have mainly focused on data aggregation in large-scale environments but have rarely discussed the issue of intra-cluster data aggregation in VANETs. In this study, we propose a multi-player game theory algorithm for intra-cluster data aggregation in VANETs by analyzing the competitive and cooperative relationships among sensor nodes. Several sensor-centric metrics are proposed to measure the data redundancy and stability of a cluster. We then study the utility function to achieve efficient intra-cluster data aggregation by considering both data redundancy and cluster stability. In particular, we prove the existence of a unique Nash equilibrium in the game model, and conduct extensive experiments to validate the proposed algorithm. Results demonstrate that the proposed algorithm has advantages over typical data aggregation algorithms in both accuracy and efficiency.

  16. SVANET: A smart vehicular ad hoc network for efficient data transmission with wireless sensors.

    PubMed

    Sahoo, Prasan Kumar; Chiang, Ming-Jer; Wu, Shih-Lin

    2014-11-25

    Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET) architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency.

  17. Data Delivery Method Based on Neighbor Nodes' Information in a Mobile Ad Hoc Network

    PubMed Central

    Hayashi, Takuma; Taenaka, Yuzo; Okuda, Takeshi; Yamaguchi, Suguru

    2014-01-01

    This paper proposes a data delivery method based on neighbor nodes' information to achieve reliable communication in a mobile ad hoc network (MANET). In a MANET, it is difficult to deliver data reliably due to instabilities in network topology and wireless network condition which result from node movement. To overcome such unstable communication, opportunistic routing and network coding schemes have lately attracted considerable attention. Although an existing method that employs such schemes, MAC-independent opportunistic routing and encoding (MORE), Chachulski et al. (2007), improves the efficiency of data delivery in an unstable wireless mesh network, it does not address node movement. To efficiently deliver data in a MANET, the method proposed in this paper thus first employs the same opportunistic routing and network coding used in MORE and also uses the location information and transmission probabilities of neighbor nodes to adapt to changeable network topology and wireless network condition. The simulation experiments showed that the proposed method can achieve efficient data delivery with low network load when the movement speed is relatively slow. PMID:24672371

  18. Enhancing the selection of backoff interval using fuzzy logic over wireless Ad Hoc networks.

    PubMed

    Ranganathan, Radha; Kannan, Kathiravan

    2015-01-01

    IEEE 802.11 is the de facto standard for medium access over wireless ad hoc network. The collision avoidance mechanism (i.e., random binary exponential backoff-BEB) of IEEE 802.11 DCF (distributed coordination function) is inefficient and unfair especially under heavy load. In the literature, many algorithms have been proposed to tune the contention window (CW) size. However, these algorithms make every node select its backoff interval between [0, CW] in a random and uniform manner. This randomness is incorporated to avoid collisions among the nodes. But this random backoff interval can change the optimal order and frequency of channel access among competing nodes which results in unfairness and increased delay. In this paper, we propose an algorithm that schedules the medium access in a fair and effective manner. This algorithm enhances IEEE 802.11 DCF with additional level of contention resolution that prioritizes the contending nodes according to its queue length and waiting time. Each node computes its unique backoff interval using fuzzy logic based on the input parameters collected from contending nodes through overhearing. We evaluate our algorithm against IEEE 802.11, GDCF (gentle distributed coordination function) protocols using ns-2.35 simulator and show that our algorithm achieves good performance.

  19. Emergency Situation Prediction Mechanism: A Novel Approach for Intelligent Transportation System Using Vehicular Ad Hoc Networks

    PubMed Central

    Gokulakrishnan, P.

    2015-01-01

    In Indian four-lane express highway, millions of vehicles are travelling every day. Accidents are unfortunate and frequently occurring in these highways causing deaths, increase in death toll, and damage to infrastructure. A mechanism is required to avoid such road accidents at the maximum to reduce the death toll. An Emergency Situation Prediction Mechanism, a novel and proactive approach, is proposed in this paper for achieving the best of Intelligent Transportation System using Vehicular Ad Hoc Network. ESPM intends to predict the possibility of occurrence of an accident in an Indian four-lane express highway. In ESPM, the emergency situation prediction is done by the Road Side Unit based on (i) the Status Report sent by the vehicles in the range of RSU and (ii) the road traffic flow analysis done by the RSU. Once the emergency situation or accident is predicted in advance, an Emergency Warning Message is constructed and disseminated to all vehicles in the area of RSU to alert and prevent the vehicles from accidents. ESPM performs well in emergency situation prediction in advance to the occurrence of an accident. ESPM predicts the emergency situation within 0.20 seconds which is comparatively less than the statistical value. The prediction accuracy of ESPM against vehicle density is found better in different traffic scenarios. PMID:26065014

  20. Road Accident Prevention with Instant Emergency Warning Message Dissemination in Vehicular Ad-Hoc Network.

    PubMed

    Gokulakrishnan, P; Ganeshkumar, P

    2015-01-01

    A Road Accident Prevention (RAP) scheme based on Vehicular Backbone Network (VBN) structure is proposed in this paper for Vehicular Ad-hoc Network (VANET). The RAP scheme attempts to prevent vehicles from highway road traffic accidents and thereby reduces death and injury rates. Once the possibility of an emergency situation (i.e. an accident) is predicted in advance, instantly RAP initiates a highway road traffic accident prevention scheme. The RAP scheme constitutes the following activities: (i) the Road Side Unit (RSU) constructs a Prediction Report (PR) based on the status of the vehicles and traffic in the highway roads, (ii) the RSU generates an Emergency Warning Message (EWM) based on an abnormal PR, (iii) the RSU forms a VBN structure and (iv) the RSU disseminates the EWM to the vehicles that holds the high Risk Factor (RF) and travels in High Risk Zone (HRZ). These vehicles might reside either within the RSU's coverage area or outside RSU's coverage area (reached using VBN structure). The RAP scheme improves the performance of EWM dissemination in terms of increase in notification and decrease in end-to-end delay. The RAP scheme also reduces infrastructure cost (number of RSUs) by formulating and deploying the VBN structure. The RAP scheme with VBN structure improves notification by 19 percent and end-to-end delay by 14.38 percent for a vehicle density of 160 vehicles. It is also proved from the simulation experiment that the performance of RAP scheme is promising in 4-lane highway roads.

  1. VehiHealth: An Emergency Routing Protocol for Vehicular Ad Hoc Network to Support Healthcare System.

    PubMed

    Bhoi, S K; Khilar, P M

    2016-03-01

    Survival of a patient depends on effective data communication in healthcare system. In this paper, an emergency routing protocol for Vehicular Ad hoc Network (VANET) is proposed to quickly forward the current patient status information from the ambulance to the hospital to provide pre-medical treatment. As the ambulance takes time to reach the hospital, ambulance doctor can provide sudden treatment to the patient in emergency by sending patient status information to the hospital through the vehicles using vehicular communication. Secondly, the experienced doctors respond to the information by quickly sending a treatment information to the ambulance. In this protocol, data is forwarded through that path which has less link breakage problem between the vehicles. This is done by calculating an intersection value I v a l u e for the neighboring intersections by using the current traffic information. Then the data is forwarded through that intersection which has minimum I v a l u e . Simulation results show VehiHealth performs better than P-GEDIR, GyTAR, A-STAR and GSR routing protocols in terms of average end-to-end delay, number of link breakage, path length, and average response time.

  2. SVANET: A Smart Vehicular Ad Hoc Network for Efficient Data Transmission with Wireless Sensors

    PubMed Central

    Sahoo, Prasan Kumar; Chiang, Ming-Jer; Wu, Shih-Lin

    2014-01-01

    Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET) architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency. PMID:25429409

  3. Enhancing the Selection of Backoff Interval Using Fuzzy Logic over Wireless Ad Hoc Networks

    PubMed Central

    Ranganathan, Radha; Kannan, Kathiravan

    2015-01-01

    IEEE 802.11 is the de facto standard for medium access over wireless ad hoc network. The collision avoidance mechanism (i.e., random binary exponential backoff—BEB) of IEEE 802.11 DCF (distributed coordination function) is inefficient and unfair especially under heavy load. In the literature, many algorithms have been proposed to tune the contention window (CW) size. However, these algorithms make every node select its backoff interval between [0, CW] in a random and uniform manner. This randomness is incorporated to avoid collisions among the nodes. But this random backoff interval can change the optimal order and frequency of channel access among competing nodes which results in unfairness and increased delay. In this paper, we propose an algorithm that schedules the medium access in a fair and effective manner. This algorithm enhances IEEE 802.11 DCF with additional level of contention resolution that prioritizes the contending nodes according to its queue length and waiting time. Each node computes its unique backoff interval using fuzzy logic based on the input parameters collected from contending nodes through overhearing. We evaluate our algorithm against IEEE 802.11, GDCF (gentle distributed coordination function) protocols using ns-2.35 simulator and show that our algorithm achieves good performance. PMID:25879066

  4. Adaptive Control Parameters for Dispersal of Multi-Agent Mobile Ad Hoc Network (MANET) Swarms

    SciTech Connect

    Kurt Derr; Milos Manic

    2013-11-01

    A mobile ad hoc network is a collection of independent nodes that communicate wirelessly with one another. This paper investigates nodes that are swarm robots with communications and sensing capabilities. Each robot in the swarm may operate in a distributed and decentralized manner to achieve some goal. This paper presents a novel approach to dynamically adapting control parameters to achieve mesh configuration stability. The presented approach to robot interaction is based on spring force laws (attraction and repulsion laws) to create near-optimal mesh like configurations. In prior work, we presented the extended virtual spring mesh (EVSM) algorithm for the dispersion of robot swarms. This paper extends the EVSM framework by providing the first known study on the effects of adaptive versus static control parameters on robot swarm stability. The EVSM algorithm provides the following novelties: 1) improved performance with adaptive control parameters and 2) accelerated convergence with high formation effectiveness. Simulation results show that 120 robots reach convergence using adaptive control parameters more than twice as fast as with static control parameters in a multiple obstacle environment.

  5. A Game Theory Algorithm for Intra-Cluster Data Aggregation in a Vehicular Ad Hoc Network

    PubMed Central

    Chen, Yuzhong; Weng, Shining; Guo, Wenzhong; Xiong, Naixue

    2016-01-01

    Vehicular ad hoc networks (VANETs) have an important role in urban management and planning. The effective integration of vehicle information in VANETs is critical to traffic analysis, large-scale vehicle route planning and intelligent transportation scheduling. However, given the limitations in the precision of the output information of a single sensor and the difficulty of information sharing among various sensors in a highly dynamic VANET, effectively performing data aggregation in VANETs remains a challenge. Moreover, current studies have mainly focused on data aggregation in large-scale environments but have rarely discussed the issue of intra-cluster data aggregation in VANETs. In this study, we propose a multi-player game theory algorithm for intra-cluster data aggregation in VANETs by analyzing the competitive and cooperative relationships among sensor nodes. Several sensor-centric metrics are proposed to measure the data redundancy and stability of a cluster. We then study the utility function to achieve efficient intra-cluster data aggregation by considering both data redundancy and cluster stability. In particular, we prove the existence of a unique Nash equilibrium in the game model, and conduct extensive experiments to validate the proposed algorithm. Results demonstrate that the proposed algorithm has advantages over typical data aggregation algorithms in both accuracy and efficiency. PMID:26907272

  6. Emergency Situation Prediction Mechanism: A Novel Approach for Intelligent Transportation System Using Vehicular Ad Hoc Networks.

    PubMed

    Ganeshkumar, P; Gokulakrishnan, P

    2015-01-01

    In Indian four-lane express highway, millions of vehicles are travelling every day. Accidents are unfortunate and frequently occurring in these highways causing deaths, increase in death toll, and damage to infrastructure. A mechanism is required to avoid such road accidents at the maximum to reduce the death toll. An Emergency Situation Prediction Mechanism, a novel and proactive approach, is proposed in this paper for achieving the best of Intelligent Transportation System using Vehicular Ad Hoc Network. ESPM intends to predict the possibility of occurrence of an accident in an Indian four-lane express highway. In ESPM, the emergency situation prediction is done by the Road Side Unit based on (i) the Status Report sent by the vehicles in the range of RSU and (ii) the road traffic flow analysis done by the RSU. Once the emergency situation or accident is predicted in advance, an Emergency Warning Message is constructed and disseminated to all vehicles in the area of RSU to alert and prevent the vehicles from accidents. ESPM performs well in emergency situation prediction in advance to the occurrence of an accident. ESPM predicts the emergency situation within 0.20 seconds which is comparatively less than the statistical value. The prediction accuracy of ESPM against vehicle density is found better in different traffic scenarios.

  7. Ad Hoc Query Support For Very Large Simulation Mesh Data: The Metadata Approach

    SciTech Connect

    Lee, B; Snapp, R; Musick, R; Critchlow, T

    2001-12-17

    We present our approach to enabling approximate ad hoc queries on terabyte-scale mesh data generated from large scientific simulations through the extension and integration of database, statistical, and data mining techniques. There are several significant barriers to overcome in achieving this objective. First, large-scale simulation data is already at the multi-terabyte scale and growing quickly, thus rendering traditional forms of interactive data exploration and query processing untenable. Second, a priori knowledge of user queries is not available, making it impossible to tune special-purpose solutions. Third, the data has spatial and temporal aspects, as well as arbitrarily high dimensionality, which exacerbates the task of finding compact, accurate, and easy-to-compute data models. Our approach is to preprocess the mesh data to generate highly compressed, lossy models that are used in lieu of the original data to answer users' queries. This approach leads to interesting challenges. The model (equivalently, the content-oriented metadata) being generated must be smaller than the original data by at least an order of magnitude. Second, the metadata representation must contain enough information to support a broad class of queries. Finally, the accuracy and speed of the queries must be within the tolerances required by users. In this paper we give an overview of ongoing development efforts with an emphasis on extracting metadata and using it in query processing.

  8. An Ad-hoc Satellite Network to Measure Filamentary Current Structures in the Auroral Zone

    NASA Astrophysics Data System (ADS)

    Nabong, C.; Fritz, T. A.; Semeter, J. L.

    2014-12-01

    An ad-hoc cubesat-based satellite network project known as ANDESITE is under development at Boston University. It aims to develop a dense constellation of easy-to-use, rapidly-deployable low-cost wireless sensor nodes in space. The objectives of the project are threefold: 1) Demonstrate viability of satellite based sensor networks by deploying an 8-node miniature sensor network to study the filamentation of the field aligned currents in the auroral zones of the Earth's magnetosphere. 2) Test the scalability of proposed protocols, including localization techniques, tracking, data aggregation, and routing, for a 3 dimensional wireless sensor network using a "flock" of nodes. 3) Construct a 6U Cube-sat running the Android OS as an integrated constellation manager, data mule and sensor node deplorer. This small network of sensor nodes will resolve current densities at different spatial resolutions in the near-Earth magnetosphere using measurements from magnetometers with 1-nT sensitivities and 0.2 nT/√Hz self-noise. Mapping of these currents will provide new constraints for models of auroral particle acceleration, wave-particle interactions, ionospheric destabilization, and other kinetic processes operating in the low-beta plasma of the near Earth magnetosphere.

  9. A communication theoretical analysis of FRET-based mobile ad hoc molecular nanonetworks.

    PubMed

    Kuscu, Murat; Akan, Ozgur B

    2014-09-01

    Nanonetworks refer to a group of nanosized machines with very basic operational capabilities communicating to each other in order to accomplish more complex tasks such as in-body drug delivery, or chemical defense. Realizing reliable and high-rate communication between these nanomachines is a fundamental problem for the practicality of these nanonetworks. Recently, we have proposed a molecular communication method based on Förster Resonance Energy Transfer (FRET) which is a nonradiative excited state energy transfer phenomenon observed among fluorescent molecules, i.e., fluorophores. We have modeled the FRET-based communication channel considering the fluorophores as single-molecular immobile nanomachines, and shown its reliability at high rates, and practicality at the current stage of nanotechnology. In this study, for the first time in the literature, we investigate the network of mobile nanomachines communicating through FRET. We introduce two novel mobile molecular nanonetworks: FRET-based mobile molecular sensor/actor nanonetwork (FRET-MSAN) which is a distributed system of mobile fluorophores acting as sensor or actor node; and FRET-based mobile ad hoc molecular nanonetwork (FRET-MAMNET) which consists of fluorophore-based nanotransmitter, nanoreceivers and nanorelays. We model the single message propagation based on birth-death processes with continuous time Markov chains. We evaluate the performance of FRET-MSAN and FRET-MAMNET in terms of successful transmission probability and mean extinction time of the messages, system throughput, channel capacity and achievable communication rates.

  10. Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks

    PubMed Central

    He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

    2017-01-01

    Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows. PMID:28714898

  11. Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks.

    PubMed

    He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

    2017-07-15

    Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows.

  12. Concurrent Transmission Based on Channel Quality in Ad Hoc Networks: A Game Theoretic Approach

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Gao, Xinbo; Li, Xiaoji; Pei, Qingqi

    In this paper, a decentralized concurrent transmission strategy in shared channel in Ad Hoc networks is proposed based on game theory. Firstly, a static concurrent transmissions game is used to determine the candidates for transmitting by channel quality threshold and to maximize the overall throughput with consideration of channel quality variation. To achieve NES (Nash Equilibrium Solution), the selfish behaviors of node to attempt to improve the channel gain unilaterally are evaluated. Therefore, this game allows each node to be distributed and to decide whether to transmit concurrently with others or not depending on NES. Secondly, as there are always some nodes with lower channel gain than NES, which are defined as hunger nodes in this paper, a hunger suppression scheme is proposed by adjusting the price function with interferences reservation and forward relay, to fairly give hunger nodes transmission opportunities. Finally, inspired by stock trading, a dynamic concurrent transmission threshold determination scheme is implemented to make the static game practical. Numerical results show that the proposed scheme is feasible to increase concurrent transmission opportunities for active nodes, and at the same time, the number of hunger nodes is greatly reduced with the least increase of threshold by interferences reservation. Also, the good performance on network goodput of the proposed model can be seen from the results.

  13. Energy Efficient Link Aware Routing with Power Control in Wireless Ad Hoc Networks

    PubMed Central

    Katiravan, Jeevaa; Sylvia, D.; Rao, D. Srinivasa

    2015-01-01

    In wireless ad hoc networks, the traditional routing protocols make the route selection based on minimum distance between the nodes and the minimum number of hop counts. Most of the routing decisions do not consider the condition of the network such as link quality and residual energy of the nodes. Also, when a link failure occurs, a route discovery mechanism is initiated which incurs high routing overhead. If the broadcast nature and the spatial diversity of the wireless communication are utilized efficiently it becomes possible to achieve improvement in the performance of the wireless networks. In contrast to the traditional routing scheme which makes use of a predetermined route for packet transmission, such an opportunistic routing scheme defines a predefined forwarding candidate list formed by using single network metrics. In this paper, a protocol is proposed which uses multiple metrics such as residual energy and link quality for route selection and also includes a monitoring mechanism which initiates a route discovery for a poor link, thereby reducing the overhead involved and improving the throughput of the network while maintaining network connectivity. Power control is also implemented not only to save energy but also to improve the network performance. Using simulations, we show the performance improvement attained in the network in terms of packet delivery ratio, routing overhead, and residual energy of the network. PMID:26167529

  14. Secure and Fair Cluster Head Selection Protocol for Enhancing Security in Mobile Ad Hoc Networks

    PubMed Central

    Paramasivan, B.; Kaliappan, M.

    2014-01-01

    Mobile ad hoc networks (MANETs) are wireless networks consisting of number of autonomous mobile devices temporarily interconnected into a network by wireless media. MANETs become one of the most prevalent areas of research in the recent years. Resource limitations, energy efficiency, scalability, and security are the great challenging issues in MANETs. Due to its deployment nature, MANETs are more vulnerable to malicious attack. The secure routing protocols perform very basic security related functions which are not sufficient to protect the network. In this paper, a secure and fair cluster head selection protocol (SFCP) is proposed which integrates security factors into the clustering approach for achieving attacker identification and classification. Byzantine agreement based cooperative technique is used for attacker identification and classification to make the network more attack resistant. SFCP used to solve this issue by making the nodes that are totally surrounded by malicious neighbors adjust dynamically their belief and disbelief thresholds. The proposed protocol selects the secure and energy efficient cluster head which acts as a local detector without imposing overhead to the clustering performance. SFCP is simulated in network simulator 2 and compared with two protocols including AODV and CBRP. PMID:25143986

  15. Medium Access Control Protocols for Cognitive Radio Ad Hoc Networks: A Survey

    PubMed Central

    Islam, A. K. M. Muzahidul; Baharun, Sabariah; Mansoor, Nafees

    2017-01-01

    New wireless network paradigms will demand higher spectrum use and availability to cope with emerging data-hungry devices. Traditional static spectrum allocation policies cause spectrum scarcity, and new paradigms such as Cognitive Radio (CR) and new protocols and techniques need to be developed in order to have efficient spectrum usage. Medium Access Control (MAC) protocols are accountable for recognizing free spectrum, scheduling available resources and coordinating the coexistence of heterogeneous systems and users. This paper provides an ample review of the state-of-the-art MAC protocols, which mainly focuses on Cognitive Radio Ad Hoc Networks (CRAHN). First, a description of the cognitive radio fundamental functions is presented. Next, MAC protocols are divided into three groups, which are based on their channel access mechanism, namely time-slotted protocol, random access protocol and hybrid protocol. In each group, a detailed and comprehensive explanation of the latest MAC protocols is presented, as well as the pros and cons of each protocol. A discussion on future challenges for CRAHN MAC protocols is included with a comparison of the protocols from a functional perspective. PMID:28926952

  16. A Sensitive Secondary Users Selection Algorithm for Cognitive Radio Ad Hoc Networks

    PubMed Central

    Li, Aohan; Han, Guangjie; Wan, Liangtian; Shu, Lei

    2016-01-01

    Secondary Users (SUs) are allowed to use the temporarily unused licensed spectrum without disturbing Primary Users (PUs) in Cognitive Radio Ad Hoc Networks (CRAHNs). Existing architectures for CRAHNs impose energy-consuming Cognitive Radios (CRs) on SUs. However, the advanced CRs will increase energy cost for their cognitive functionalities, which is undesirable for the battery powered devices. A new architecture referred to as spectral Requirement-based CRAHN (RCRAHN) is proposed to enhance energy efficiency for CRAHNs in this paper. In RCRAHNs, only parts of SUs are equipped with CRs. SUs equipped with CRs are referred to as Cognitive Radio Users (CRUs). To further enhance energy efficiency of CRAHNs, we aim to select minimum CRUs to sense available spectrum. A non-linear programming problem is mathematically formulated under the constraints of energy efficiency and real-time. Considering the NP-hardness of the problem, a framework of a heuristic algorithm referred to as Sensitive Secondary Users Selection (SSUS) was designed to compute the near-optimal solutions. The simulation results demonstrate that SSUS not only improves the energy efficiency, but also achieves satisfied performances in end-to-end delay and communication reliability. PMID:27023562

  17. Multiobjective Reinforcement Learning for Traffic Signal Control Using Vehicular Ad Hoc Network

    NASA Astrophysics Data System (ADS)

    Houli, Duan; Zhiheng, Li; Yi, Zhang

    2010-12-01

    We propose a new multiobjective control algorithm based on reinforcement learning for urban traffic signal control, named multi-RL. A multiagent structure is used to describe the traffic system. A vehicular ad hoc network is used for the data exchange among agents. A reinforcement learning algorithm is applied to predict the overall value of the optimization objective given vehicles' states. The policy which minimizes the cumulative value of the optimization objective is regarded as the optimal one. In order to make the method adaptive to various traffic conditions, we also introduce a multiobjective control scheme in which the optimization objective is selected adaptively to real-time traffic states. The optimization objectives include the vehicle stops, the average waiting time, and the maximum queue length of the next intersection. In addition, we also accommodate a priority control to the buses and the emergency vehicles through our model. The simulation results indicated that our algorithm could perform more efficiently than traditional traffic light control methods.

  18. Standardization of negative controls in diagnostic immunohistochemistry: recommendations from the international ad hoc expert panel.

    PubMed

    Torlakovic, Emina E; Francis, Glenn; Garratt, John; Gilks, Blake; Hyjek, Elizabeth; Ibrahim, Merdol; Miller, Rodney; Nielsen, Søren; Petcu, Eugen B; Swanson, Paul E; Taylor, Clive R; Vyberg, Mogens

    2014-04-01

    Standardization of controls, both positive and negative controls, is needed for diagnostic immunohistochemistry (dIHC). The use of IHC-negative controls, irrespective of type, although well established, is not standardized. As such, the relevance and applicability of negative controls continues to challenge both pathologists and laboratory budgets. Despite the clear theoretical notion that appropriate controls serve to demonstrate the sensitivity and specificity of the dIHC test, it remains unclear which types of positive and negative controls are applicable and/or useful in day-to-day clinical practice. There is a perceived need to provide "best practice recommendations" for the use of negative controls. This perception is driven not only by logistics and cost issues, but also by increased pressure for accurate IHC testing, especially when IHC is performed for predictive markers, the number of which is rising as personalized medicine continues to develop. Herein, an international ad hoc expert panel reviews classification of negative controls relevant to clinical practice, proposes standard terminology for negative controls, considers the total evidence of IHC specificity that is available to pathologists, and develops a set of recommendations for the use of negative controls in dIHC based on "fit-for-use" principles.

  19. A commentary on the disparate perspectives of clinical microbiologists and surgeons: ad hoc antimicrobial use.

    PubMed

    O'Connell, Nuala H; O'Connor, Ciara; O'Mahony, Jim; Lobo, Ronstan; Hayes, Maria; Masterson, Eric; Larvin, Michael; Coffey, J Calvin; Dunne, Colum

    2014-01-01

    Prosthetic joints and other orthopedic implants have improved quality of life for patients world-wide and the use of such devices is increasing. However, while infection rates subsequent to associated surgery are relatively low (<3%), the consequences of incidence are considerable, encompassing morbidity (including amputation) and mortality in addition to significant social and economic costs. Emphasis, therefore, has been placed on mitigating microbial risk, with clinical microbiologists and surgeons utilizing rapidly evolving molecular laboratory techniques in detection and diagnosis of infection, which still occurs despite sophisticated patient management. Multidisciplinary approaches are regularly adopted to achieve this. In this commentary, we describe an unusual case of Actinomyces infection in total hip arthroplasty and, in that context, describe the perspectives of the clinical microbiology and surgical teams and how they contrasted. More specifically, this case demonstrates an ad hoc approach to structured eradication of biofilms and intracellular bacteria related to biomaterials, as reflected in early usage of linezolid. This is a complex topic and, as described in this case, such accelerated treatment can be effective. This commentary focuses on the merits of such inadvisable use of potent antimicrobials amid the risk of diminishing valuable antimicrobial efficacy, albeit resulting in desirable patient outcomes.

  20. An adaptive neural swarm approach for intrusion defense in ad hoc networks

    NASA Astrophysics Data System (ADS)

    Cannady, James

    2011-06-01

    Wireless sensor networks (WSN) and mobile ad hoc networks (MANET) are being increasingly deployed in critical applications due to the flexibility and extensibility of the technology. While these networks possess numerous advantages over traditional wireless systems in dynamic environments they are still vulnerable to many of the same types of host-based and distributed attacks common to those systems. Unfortunately, the limited power and bandwidth available in WSNs and MANETs, combined with the dynamic connectivity that is a defining characteristic of the technology, makes it extremely difficult to utilize traditional intrusion detection techniques. This paper describes an approach to accurately and efficiently detect potentially damaging activity in WSNs and MANETs. It enables the network as a whole to recognize attacks, anomalies, and potential vulnerabilities in a distributive manner that reflects the autonomic processes of biological systems. Each component of the network recognizes activity in its local environment and then contributes to the overall situational awareness of the entire system. The approach utilizes agent-based swarm intelligence to adaptively identify potential data sources on each node and on adjacent nodes throughout the network. The swarm agents then self-organize into modular neural networks that utilize a reinforcement learning algorithm to identify relevant behavior patterns in the data without supervision. Once the modular neural networks have established interconnectivity both locally and with neighboring nodes the analysis of events within the network can be conducted collectively in real-time. The approach has been shown to be extremely effective in identifying distributed network attacks.

  1. Training and development for radiographers' extended roles: a case of ad hoc implementation.

    PubMed

    Miller, Linda; Price, Richard; Vosper, Martin

    2011-05-01

    This paper examines the quality and consistency of postregistration training and development for extended role activities undertaken by radiographers. Although the undergraduate curriculum has changed to some extent to accommodate expanded role requirements, much of the training does not, and cannot, take place until radiographers are qualified and are in post. While undergraduate programmes in radiography must be approved by the Health Professions Council, and are normally accredited by the radiographers' professional body, the Society and College of Radiographers, much of the training provided for extended role activities is ad hoc and neither validated nor accredited. This paper reports the outcomes of a survey of imaging service managers and follow-up interviews with imaging service managers. Managers' views of the quality of training and development provided for extended role activities and their approaches to recruiting radiographers with extended role experience, were explored. The research identified concerns among managers regarding the training currently available and indicated potential career disadvantages for radiographers receiving unaccredited development. There is also some evidence of wastage arising from the duplication of training by trusts because of uncertainty about the standards of competence instilled by programmes.

  2. Securing Mobile Ad Hoc Networks Using Danger Theory-Based Artificial Immune Algorithm

    PubMed Central

    2015-01-01

    A mobile ad hoc network (MANET) is a set of mobile, decentralized, and self-organizing nodes that are used in special cases, such as in the military. MANET properties render the environment of this network vulnerable to different types of attacks, including black hole, wormhole and flooding-based attacks. Flooding-based attacks are one of the most dangerous attacks that aim to consume all network resources and thus paralyze the functionality of the whole network. Therefore, the objective of this paper is to investigate the capability of a danger theory-based artificial immune algorithm called the mobile dendritic cell algorithm (MDCA) to detect flooding-based attacks in MANETs. The MDCA applies the dendritic cell algorithm (DCA) to secure the MANET with additional improvements. The MDCA is tested and validated using Qualnet v7.1 simulation tool. This work also introduces a new simulation module for a flooding attack called the resource consumption attack (RCA) using Qualnet v7.1. The results highlight the high efficiency of the MDCA in detecting RCAs in MANETs. PMID:25946001

  3. Securing mobile ad hoc networks using danger theory-based artificial immune algorithm.

    PubMed

    Abdelhaq, Maha; Alsaqour, Raed; Abdelhaq, Shawkat

    2015-01-01

    A mobile ad hoc network (MANET) is a set of mobile, decentralized, and self-organizing nodes that are used in special cases, such as in the military. MANET properties render the environment of this network vulnerable to different types of attacks, including black hole, wormhole and flooding-based attacks. Flooding-based attacks are one of the most dangerous attacks that aim to consume all network resources and thus paralyze the functionality of the whole network. Therefore, the objective of this paper is to investigate the capability of a danger theory-based artificial immune algorithm called the mobile dendritic cell algorithm (MDCA) to detect flooding-based attacks in MANETs. The MDCA applies the dendritic cell algorithm (DCA) to secure the MANET with additional improvements. The MDCA is tested and validated using Qualnet v7.1 simulation tool. This work also introduces a new simulation module for a flooding attack called the resource consumption attack (RCA) using Qualnet v7.1. The results highlight the high efficiency of the MDCA in detecting RCAs in MANETs.

  4. Linear QoS goals of additive and concave metrics in ad hoc cognitive packet routing.

    PubMed

    Lent, Ricardo

    2006-12-01

    This paper addresses two scalability problems related to the cognitive map of packets in ad hoc cognitive packet networks and proposes a solution. Previous works have included latency as part of the routing goal of smart packets, which requires packets to collect their arrival time at each node in a path. Such a requirement resulted in a packet overhead proportional to the path length. The second problem is that the multiplicative form of path availability, which was employed to measure resources, loses accuracy in long paths. To solve these problems, new goals are proposed in this paper. These goals are linear functions of low-overhead metrics and can provide similar performance results with lower cost. One direct result shown in simulation is that smart packets driven by a linear function of path length and buffer occupancy can effectively balance the traffic of multiple flows without the large overhead that would be needed if round-trip delay was used. In addition, energy-aware routing is also studied under this scheme as well as link selection based on their expected level of security.

  5. Road Accident Prevention with Instant Emergency Warning Message Dissemination in Vehicular Ad-Hoc Network

    PubMed Central

    P, Gokulakrishnan; P, Ganeshkumar

    2015-01-01

    A Road Accident Prevention (RAP) scheme based on Vehicular Backbone Network (VBN) structure is proposed in this paper for Vehicular Ad-hoc Network (VANET). The RAP scheme attempts to prevent vehicles from highway road traffic accidents and thereby reduces death and injury rates. Once the possibility of an emergency situation (i.e. an accident) is predicted in advance, instantly RAP initiates a highway road traffic accident prevention scheme. The RAP scheme constitutes the following activities: (i) the Road Side Unit (RSU) constructs a Prediction Report (PR) based on the status of the vehicles and traffic in the highway roads, (ii) the RSU generates an Emergency Warning Message (EWM) based on an abnormal PR, (iii) the RSU forms a VBN structure and (iv) the RSU disseminates the EWM to the vehicles that holds the high Risk Factor (RF) and travels in High Risk Zone (HRZ). These vehicles might reside either within the RSU’s coverage area or outside RSU’s coverage area (reached using VBN structure). The RAP scheme improves the performance of EWM dissemination in terms of increase in notification and decrease in end-to-end delay. The RAP scheme also reduces infrastructure cost (number of RSUs) by formulating and deploying the VBN structure. The RAP scheme with VBN structure improves notification by 19 percent and end-to-end delay by 14.38 percent for a vehicle density of 160 vehicles. It is also proved from the simulation experiment that the performance of RAP scheme is promising in 4-lane highway roads. PMID:26636576

  6. Exploring the Role of Ad Hoc Grassroots Organizations Providing Humanitarian Aid on Lesvos, Greece

    PubMed Central

    Kitching, George Tjensvoll; J. Haavik, Hanne; Tandstad, Birgit J.; Zaman, Muhammad; Darj, Elisabeth

    2016-01-01

    Introduction: Syrian refugees displaced into Turkey have attempted high-risk sea migrations to reach safer destinations in Europe, most often initially arriving on the Greek island of Lesvos. These refugees were often in need of basic humanitarian assistance that has been provided in part by a new category of ad hoc grassroots organizations (AHGOs). The aim of this study was to understand the internal and external operations of these AHGOs and their role on Lesvos. Methods: The experiences of AHGOs were investigated through a qualitative research design utilizing semi-structured interviews with organization leaders and spokespersons. AHGOs identified through media and social media sources as new Lesvos-specific organizations were purposively invited to complete an interview over phone, Skype or email. Data analysis of the transcribed interviews was performed by Systematic Text Condensation. Results: Forty-one organizations were contacted and 13 interviews were conducted. Most organizations were formed in autumn 2015 responding to the greater influx of refugees and migrants at that time and reported an absence of professional humanitarian agencies providing aid on Lesvos. Three categories emerged from the material. Features of organizations; Features of volunteers and; Evolution of AHGOs. The organizations perceived themselves capable of evaluating needs, mobilizing resources, funding and providing quick response. The volunteers came with limited humanitarian experience and from a wide variety of nationalities and professional backgrounds, and the organizations developed while on Lesvos. Discussion: Knowledge from our findings of AHGOs response to this complex disaster on Lesvos could be utilized in future catastrophes. We conclude that AHGOs may prove effective at providing humanitarian aid in a surge response when international non-governmental organizations are unable to respond quickly. In future complex disasters AHGOs should be recognized as new humanitarian

  7. Performance evaluation of reactive and proactive routing protocol in IEEE 802.11 ad hoc network

    NASA Astrophysics Data System (ADS)

    Hamma, Salima; Cizeron, Eddy; Issaka, Hafiz; Guédon, Jean-Pierre

    2006-10-01

    Wireless technology based on the IEEE 802.11 standard is widely deployed. This technology is used to support multiple types of communication services (data, voice, image) with different QoS requirements. MANET (Mobile Adhoc NETwork) does not require a fixed infrastructure. Mobile nodes communicate through multihop paths. The wireless communication medium has variable and unpredictable characteristics. Furthermore, node mobility creates a continuously changing communication topology in which paths break and new one form dynamically. The routing table of each router in an adhoc network must be kept up-to-date. MANET uses Distance Vector or Link State algorithms which insure that the route to every host is always known. However, this approach must take into account the adhoc networks specific characteristics: dynamic topologies, limited bandwidth, energy constraints, limited physical security, ... Two main routing protocols categories are studied in this paper: proactive protocols (e.g. Optimised Link State Routing - OLSR) and reactive protocols (e.g. Ad hoc On Demand Distance Vector - AODV, Dynamic Source Routing - DSR). The proactive protocols are based on periodic exchanges that update the routing tables to all possible destinations, even if no traffic goes through. The reactive protocols are based on on-demand route discoveries that update routing tables only for the destination that has traffic going through. The present paper focuses on study and performance evaluation of these categories using NS2 simulations. We have considered qualitative and quantitative criteria. The first one concerns distributed operation, loop-freedom, security, sleep period operation. The second are used to assess performance of different routing protocols presented in this paper. We can list end-to-end data delay, jitter, packet delivery ratio, routing load, activity distribution. Comparative study will be presented with number of networking context consideration and the results show

  8. Bringing Ad-Hoc Analytics to Big Earth Data: the EarthServer Experience

    NASA Astrophysics Data System (ADS)

    Baumann, Peter

    2014-05-01

    From the commonly accepted Vs defining the Big Data challenge - volume, velocity, variety - we more and more learn that the sheer volume is not the only, and often not even the decisive factor inhibiting access and analytics. In particular variety of data is a frequent core issue, posing manifold issues. Based on this observation we claim that a key aspect to analytics is the freedom to ask any questions, simple or complex, anytime and combining any choice of data structures, whatever diverging they may be. Actually, techniques for such "ad-hoc queries" we can learn from classical databases. Their concept of high-level query languages brings along several benefits: a uniform semantic, allowing machine-to-machine communication, including automatic generation of queries; massive server-side optimization and parallelization; and building attractive client interfaces hiding the query syntax from casual users while allowing power users to utilize it. However, these benefits used to be available only on tabular and set oriented data, text, and - more recently - graph data. With the advent of Array Databases, they become available on large multidimensional raster data assets as well, getting one step closer to the Holy Grail of itnegrated, uniform retrieval for users. ErthServer is a transatlantic initiative setting up operationa linfrastructures based on this paradigm. In our talk, we present core EarthServer technology concepts as well as a spectrum of Earth Science applications utilizing the EarthServer platform for versatile, visualisation supported analytics services. Further, we discuss the substantial impact EarthServer is having on Big Geo Data standardization in OGC and ISO. Time and Internet connection permitting a live demo can be presented.

  9. HOW GAS-DYNAMIC FLARE MODELS POWERED BY PETSCHEK RECONNECTION DIFFER FROM THOSE WITH AD HOC ENERGY SOURCES

    SciTech Connect

    Longcope, D. W.; Klimchuk, J. A.

    2015-11-10

    Aspects of solar flare dynamics, such as chromospheric evaporation and flare light curves, have long been studied using one-dimensional models of plasma dynamics inside a static flare loop, subjected to some energy input. While extremely successful at explaining the observed characteristics of flares, all such models so far have specified energy input ad hoc, rather than deriving it self-consistently. There is broad consensus that flares are powered by magnetic energy released through reconnection. Recent work has generalized Petschek’s basic reconnection scenario, topological change followed by field line retraction and shock heating, to permit its inclusion in a one-dimensional flare loop model. Here we compare the gas dynamics driven by retraction and shocking to those from more conventional static loop models energized by ad hoc source terms. We find significant differences during the first minute, when retraction leads to larger kinetic energies and produces higher densities at the loop top, while ad hoc heating tends to rarify the loop top. The loop-top density concentration is related to the slow magnetosonic shock, characteristic of Petschek’s model, but persists beyond the retraction phase occurring in the outflow jet. This offers an explanation for observed loop-top sources of X-ray and EUV emission, with advantages over that provided by ad hoc heating scenarios. The cooling phases of the two models are, however, notably similar to one another, suggesting that observations at that stage will yield little information on the nature of energy input.

  10. Use of synthesized data to support complex ad-hoc queries in an enterprise information warehouse: a diabetes use case.

    PubMed

    Rogers, Patrick; Erdal, Selnur; Santangelo, Jennifer; Liu, Jianhua; Schuster, Dara; Kamal, Jyoti

    2008-11-06

    The Ohio State University Medical Center (OSUMC) Information Warehouse (IW) is a comprehensive data warehousing facility incorporating operational, clinical, and biological data sets from multiple enterprise system. It is common for users of the IW to request complex ad-hoc queries that often require significant intervention by data analyst. In response to this challenge, we have designed a workflow that leverages synthesized data elements to support such queries in an more timely, efficient manner.

  11. Report of the Ad Hoc Subgroup on the Impact of Competition in Contracting on Research and Development

    DTIC Science & Technology

    1988-06-01

    NUMBER(O LTG Robert Lunn (US Army Ret), Dr. Barbara Glacel, Ms. Naomi J. McAfee, Mr. John Moore, Mr. Edward A. Miller, Dr. Leon Riebman, Mr. Harrison H...Comments on Terms of Reference and Panel Questions 11. Paper dated 20 Jun 88 submitted by Mr. John R. Moore, Subject: Considerations and Issues... Sculley Assistant Secretary of the Army (Research, Development and Acquisition) I September 1987 PARTICIPANTS LIST ARMY SCIENCE BOARD AD HOC SUBGROUP ON

  12. Ad hoc supervision of general practice registrars as a 'community of practice': analysis, interpretation and re-presentation.

    PubMed

    Clement, T; Brown, J; Morrison, J; Nestel, D

    2016-05-01

    General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also provide an opportunity for learning and teaching. Wenger's (Communities of practice: learning, meaning, and identity. Cambridge University Press, New York, 1998) social theory of learning ('communities of practice') guided a secondary analysis of audio-recordings of ad hoc encounters. Data from one encounter is re-presented as an extended sequence to maintain congruence with the theoretical perspective and enhance vicariousness. An interpretive commentary communicates key features of Wenger's theory and highlights the researchers' interpretations. We argue that one encounter can reveal universal understandings of clinical supervision and that the process of naturalistic generalisation allows readers to transfer others' experiences to their own contexts. The paper raises significant analytic, interpretive, and representational issues. We highlight that report writing is an important, but infrequently discussed, part of research design. We discuss the challenges of supporting the learning and teaching that arises from adopting a socio-cultural lens and argue that such a perspective importantly captures the complex range of issues that work-based practitioners have to grapple with. This offers a challenge to how we research and seek to influence work-based learning and teaching in health care settings.

  13. Unsupervised algorithms for intrusion detection and identification in wireless ad hoc sensor networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2009-05-01

    In previous work by the author, parameters across network protocol layers were selected as features in supervised algorithms that detect and identify certain intrusion attacks on wireless ad hoc sensor networks (WSNs) carrying multisensor data. The algorithms improved the residual performance of the intrusion prevention measures provided by any dynamic key-management schemes and trust models implemented among network nodes. The approach of this paper does not train algorithms on the signature of known attack traffic, but, instead, the approach is based on unsupervised anomaly detection techniques that learn the signature of normal network traffic. Unsupervised learning does not require the data to be labeled or to be purely of one type, i.e., normal or attack traffic. The approach can be augmented to add any security attributes and quantified trust levels, established during data exchanges among nodes, to the set of cross-layer features from the WSN protocols. A two-stage framework is introduced for the security algorithms to overcome the problems of input size and resource constraints. The first stage is an unsupervised clustering algorithm which reduces the payload of network data packets to a tractable size. The second stage is a traditional anomaly detection algorithm based on a variation of support vector machines (SVMs), whose efficiency is improved by the availability of data in the packet payload. In the first stage, selected algorithms are adapted to WSN platforms to meet system requirements for simple parallel distributed computation, distributed storage and data robustness. A set of mobile software agents, acting like an ant colony in securing the WSN, are distributed at the nodes to implement the algorithms. The agents move among the layers involved in the network response to the intrusions at each active node and trustworthy neighborhood, collecting parametric values and executing assigned decision tasks. This minimizes the need to move large amounts

  14. 75 FR 33838 - NASA Advisory Council; Ad-Hoc Task Force on Planetary Defense; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    .... Asteroid detection, warning, response, and concepts for deflection. International coordination on planetary..., Advisory Committee Management Officer, National Aeronautics and Space Administration. BILLING CODE P...

  15. Connecting the Edge: Mobile Ad-Hoc Networks (MANETs) for Network Centric Warfare

    DTIC Science & Technology

    2007-04-01

    general conquer the enemy whenever they move and their achievements surpass those of ordinary men is foreknowledge.” Sun-Tzu, The Art of War...earliest days of warfare. In The Art of War, Sun-Tzu makes frequent mention of the importance of withholding knowledge of intent or disposition of...Hoc Networking - the Art of Networking without a Network." Ericsson Review 4 (2000): 248-63. Ghosh, Anup. "Defending Warfighter Networks." Paper

  16. Awareness of Emerging Wireless Technologies: Ad-hoc and Personal Area Networks Standards and Emerging Technologies (Sensibilisation a l’emergence des technologies sans fil: technologies emergeantes et normes de reseaux personnels et ad-hoc)

    DTIC Science & Technology

    2007-04-01

    Projet Hipercom – INRIA Rocquencourt. [14] Performance analysis of OLSR Multipoint Relay flooding in two ad hoc wireless network models N°4260...comporter la dénomination « RTO » ou « AGARD » selon le cas, suivi du numéro de série. Des informations analogues, telles que le titre est la date de...RTO » ou « AGARD » selon le cas, suivie du numéro de série (par exemple AGARD-AG-315). Des informations analogues, telles que le titre et la date

  17. Building a Simulation Toolkit for Wireless Mesh Clusters and Evaluating the Suitability of Different Families of Ad Hoc Protocols for the Tactical Network Topology

    DTIC Science & Technology

    2005-03-01

    toolkit. 15. NUMBER OF PAGES 99 14. SUBJECT TERMS Ad Hoc Networking, MANET, Wireless Mesh Networks, OLSR , DSR, AODV, Tactical Network...18 E. NETWORK LAYER PROTOCOLS ...........................................................18 1. OLSR ...34 1. OLSR ...................................................................................................34 2. DSR

  18. BCDP: Budget Constrained and Delay-Bounded Placement for Hybrid Roadside Units in Vehicular Ad Hoc Networks

    PubMed Central

    Li, Peng; Huang, Chuanhe; Liu, Qin

    2014-01-01

    In vehicular ad hoc networks, roadside units (RSUs) placement has been proposed to improve the the overall network performance in many ITS applications. This paper addresses the budget constrained and delay-bounded placement problem (BCDP) for roadside units in vehicular ad hoc networks. There are two types of RSUs: cable connected RSU (c-RSU) and wireless RSU (w-RSU). c-RSUs are interconnected through wired lines, and they form the backbone of VANETs, while w-RSUs connect to other RSUs through wireless communication and serve as an economical extension of the coverage of c-RSUs. The delay-bounded coverage range and deployment cost of these two cases are totally different. We are given a budget constraint and a delay bound, the problem is how to find the optimal candidate sites with the maximal delay-bounded coverage to place RSUs such that a message from any c-RSU in the region can be disseminated to the more vehicles within the given budget constraint and delay bound. We first prove that the BCDP problem is NP-hard. Then we propose several algorithms to solve the BCDP problem. Simulation results show the heuristic algorithms can significantly improve the coverage range and reduce the total deployment cost, compared with other heuristic methods. PMID:25436656

  19. BCDP: Budget constrained and delay-bounded placement for hybrid roadside units in vehicular ad hoc networks.

    PubMed

    Li, Peng; Huang, Chuanhe; Liu, Qin

    2014-11-27

    In vehicular ad hoc networks, roadside units (RSUs) placement has been proposed to improve the the overall network performance in many ITS applications. This paper addresses the budget constrained and delay-bounded placement problem (BCDP) for roadside units in vehicular ad hoc networks. There are two types of RSUs: cable connected RSU (c-RSU) and wireless RSU (w-RSU). c-RSUs are interconnected through wired lines, and they form the backbone of VANETs, while w-RSUs connect to other RSUs through wireless communication and serve as an economical extension of the coverage of c-RSUs. The delay-bounded coverage range and deployment cost of these two cases are totally different. We are given a budget constraint and a delay bound, the problem is how to find the optimal candidate sites with the maximal delay-bounded coverage to place RSUs such that a message from any c-RSU in the region can be disseminated to the more vehicles within the given budget constraint and delay bound. We first prove that the BCDP problem is NP-hard. Then we propose several algorithms to solve the BCDP problem. Simulation results show the heuristic algorithms can significantly improve the coverage range and reduce the total deployment cost, compared with other heuristic methods.

  20. Predicting impact of multi-paths on phase change in map-based vehicular ad hoc networks

    NASA Astrophysics Data System (ADS)

    Rahmes, Mark; Lemieux, George; Sonnenberg, Jerome; Chester, David B.

    2014-05-01

    Dynamic Spectrum Access, which through its ability to adapt the operating frequency of a radio, is widely believed to be a solution to the limited spectrum problem. Mobile Ad Hoc Networks (MANETs) can extend high capacity mobile communications over large areas where fixed and tethered-mobile systems are not available. In one use case with high potential impact cognitive radio employs spectrum sensing to facilitate identification of allocated frequencies not currently accessed by their primary users. Primary users own the rights to radiate at a specific frequency and geographic location, secondary users opportunistically attempt to radiate at a specific frequency when the primary user is not using it. We quantify optimal signal detection in map based cognitive radio networks with multiple rapidly varying phase changes and multiple orthogonal signals. Doppler shift occurs due to reflection, scattering, and rapid vehicle movement. Path propagation as well as vehicle movement produces either constructive or destructive interference with the incident wave. Our signal detection algorithms can assist the Doppler spread compensation algorithm by deciding how many phase changes in signals are present in a selected band of interest. Additionally we can populate a spatial radio environment map (REM) database with known information that can be leveraged in an ad hoc network to facilitate Dynamic Spectrum Access. We show how topography can help predict the impact of multi-paths on phase change, as well as about the prediction from dense traffic areas. Utilization of high resolution geospatial data layers in RF propagation analysis is directly applicable.

  1. A Novel Clustering Algorithm for Mobile Ad Hoc Networks Based on Determination of Virtual Links' Weight to Increase Network Stability

    PubMed Central

    Karimi, Abbas; Afsharfarnia, Abbas; Zarafshan, Faraneh; Al-Haddad, S. A. R.

    2014-01-01

    The stability of clusters is a serious issue in mobile ad hoc networks. Low stability of clusters may lead to rapid failure of clusters, high energy consumption for reclustering, and decrease in the overall network stability in mobile ad hoc network. In order to improve the stability of clusters, weight-based clustering algorithms are utilized. However, these algorithms only use limited features of the nodes. Thus, they decrease the weight accuracy in determining node's competency and lead to incorrect selection of cluster heads. A new weight-based algorithm presented in this paper not only determines node's weight using its own features, but also considers the direct effect of feature of adjacent nodes. It determines the weight of virtual links between nodes and the effect of the weights on determining node's final weight. By using this strategy, the highest weight is assigned to the best choices for being the cluster heads and the accuracy of nodes selection increases. The performance of new algorithm is analyzed by using computer simulation. The results show that produced clusters have longer lifetime and higher stability. Mathematical simulation shows that this algorithm has high availability in case of failure. PMID:25114965

  2. Revision of the venous clinical severity score: venous outcomes consensus statement: special communication of the American Venous Forum Ad Hoc Outcomes Working Group.

    PubMed

    Vasquez, Michael A; Rabe, Eberhard; McLafferty, Robert B; Shortell, Cynthia K; Marston, William A; Gillespie, David; Meissner, Mark H; Rutherford, Robert B

    2010-11-01

    In response to the need for a disease severity measurement, the American Venous Forum committee on outcomes assessment developed the Venous Severity Scoring system in 2000. There are three components of this scoring system, the Venous Disability Score, the Venous Segmental Disease Score, and the Venous Clinical Severity Score (VCSS). The VCSS was developed from elements of the CEAP classification (clinical grade, etiology, anatomy, pathophysiology), which is the worldwide standard for describing the clinical features of chronic venous disease. However, as a descriptive instrument, the CEAP classification responds poorly to change. The VCSS was subsequently developed as an evaluative instrument that would be responsive to changes in disease severity over time and in response to treatment. Based on initial experiences with the VCSS, an international ad hoc working group of the American Venous Forum was charged with updating the instrument. This revision of the VCSS is focused on clarifying ambiguities, updating terminology, and simplifying application. The specific language of proven quality-of-life instruments was used to better address the issues of patients at the lower end of the venous disease spectrum. Periodic review and revision are necessary for generating more universal applicability and for comparing treatment outcomes in a meaningful way.

  3. Evaluating the Importance of Image-related Text for Ad-hoc and Case-based Biomedical Article Retrieval.

    PubMed

    Simpson, Matthew S; Demner-Fushman, Dina; Thoma, George R

    2010-11-13

    Images and their associated text are an essential source of information in biomedical articles. However, their use in providing evidence for clinical case descriptions has yet to be evaluated in the context of information retrieval. Given the complexity of case-based document retrieval, understanding the importance of images and image-related text is critical for future research into text- and content-based approaches to this problem. In this study, we compare the extent to which image-related text is useful in facilitating document retrieval for both case-based information requests and ad-hoc clinical questions in the domain of family practice. We show that case-based document retrieval is significantly improved with the use of image-related text whereas retrieval for clinical questions is largely unaffected. This suggests that visual evidence is more relevant for the case descriptions used in our study than the clinical questions.

  4. Improving the signal-to-noise ratio of an ECL-based sensor using ad hoc carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Sanginario, A.; Giorcelli, M.; Tagliaferro, A.; Demarchi, D.

    2012-07-01

    In this paper, we demonstrate that mechanically modified cylinder-shaped carbon nanotube (CNT) working electrodes (WEs), combined with an averaging processing algorithm, can increase electrogenerated chemiluminescence (ECL) limit of detection by more than one order of magnitude, compared to gold electrodes. With CNT WEs, we obtained a stable light emission that lasts for hundreds of voltammetric cycles. This stability was further exploited to increase the detection limit with a simple algorithm, based on mean calculation. Ad hoc fabricated sensors are characterized with a full-custom potentiostat testbed and software platform, using tris(2,2-bipyridyl)ruthenium (II) as ECL labels. Our measurement results show that the signal-to-noise ratio (SNR) improves by a factor of larger than 20 compared to standard gold WEs to reach a detection limit up to 40 pg μl-1.

  5. Report of the NASA Ad Hoc Committee on failure of high strength structural materials

    NASA Technical Reports Server (NTRS)

    Brown, W. F., Jr. (Editor)

    1972-01-01

    An analysis of structural failures that have occurred in NASA programs was conducted. Reports of 231 examples of structural failure were reviewed. Attempts were made to identify those factors which contributed to the failures, and recommendations were formulated for actions which would minimize their effects on future NASA programs. Two classes of factors were identified: (1) those associated with deficiencies in existing materials and structures technology and (2) those attributable to inadequate documentation or communication of that technology.

  6. MLA Ad Hoc Committee on the Professionalization of PhDs.

    ERIC Educational Resources Information Center

    ADFL Bulletin, 2003

    2003-01-01

    Investigates how the continuing oversupply of PhDs in relation to the number of academic positions available in colleges and universities affects graduate education. Summarizes opinions about the meaning of professionalization and the roles that institutions, departments, and graduate students themselves share in the development of…

  7. Ad Hoc Committee on NAEP Parent Engagement: Reaching Parents with NAEP Resources

    ERIC Educational Resources Information Center

    National Assessment Governing Board, 2012

    2012-01-01

    The National Assessment Governing Board, recognizing that National Assessment of Educational Progress (NAEP) report releases were not conveying a sense of urgency, began an initiative in May 2010 to see what the Board could do to "make a difference" in fostering concern and action about the need to improve achievement and reduce…

  8. Potentials, Limitations and Applications of long-term and mobile ad-hoc Wireless Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Lapteva, Yulia; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2014-05-01

    To characterize environmental systems it is necessary to identify and describe processes with suitable methods. Environmental systems are often characterized by their high heterogeneity, so individual measurements for their complete representation are often not sufficient. The application of wireless sensor networks in terrestrial and aquatic ecosystems offer significant benefits as a better consideration of the local test conditions becomes possible. This can be essential for the monitoring of heterogeneous environmental systems. Significant advantages in the application of mobile ad-hoc wireless sensor networks are their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, a point measurement with a sensor is significantly improved by measuring at several points. It is also possible to perform analog and digital signal processing and computation on the basis of the measured data close to the sensor. Hence, a significant reduction of the data to be transmitted can be achieved which leads to a better energy management of sensor nodes. Furthermore, their localization via satellite, the miniaturization of the nodes and long-term energy self-sufficiency are current topics under investigation. The possibilities and limitations of the applicability of wireless sensor networks for long-term and mobile environmental monitoring are presented. A concepts and realization example are given in the field of micrometeorology and soil parameters for the interaction of biotic and abiotic processes .This long term monitoring is part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Furthermore a mobile ad-hoc sensor network is presented for the monitoring of water induced mass wasting processes.

  9. On using multiple routing metrics with destination sequenced distance vector protocol for MultiHop wireless ad hoc networks

    NASA Astrophysics Data System (ADS)

    Mehic, M.; Fazio, P.; Voznak, M.; Partila, P.; Komosny, D.; Tovarek, J.; Chmelikova, Z.

    2016-05-01

    A mobile ad hoc network is a collection of mobile nodes which communicate without a fixed backbone or centralized infrastructure. Due to the frequent mobility of nodes, routes connecting two distant nodes may change. Therefore, it is not possible to establish a priori fixed paths for message delivery through the network. Because of its importance, routing is the most studied problem in mobile ad hoc networks. In addition, if the Quality of Service (QoS) is demanded, one must guarantee the QoS not only over a single hop but over an entire wireless multi-hop path which may not be a trivial task. In turns, this requires the propagation of QoS information within the network. The key to the support of QoS reporting is QoS routing, which provides path QoS information at each source. To support QoS for real-time traffic one needs to know not only minimum delay on the path to the destination but also the bandwidth available on it. Therefore, throughput, end-to-end delay, and routing overhead are traditional performance metrics used to evaluate the performance of routing protocol. To obtain additional information about the link, most of quality-link metrics are based on calculation of the lost probabilities of links by broadcasting probe packets. In this paper, we address the problem of including multiple routing metrics in existing routing packets that are broadcasted through the network. We evaluate the efficiency of such approach with modified version of DSDV routing protocols in ns-3 simulator.

  10. A Discussion of Metrics for Parallelized Army Mobile ad hoc Network Simulations

    DTIC Science & Technology

    2011-09-01

    years including Yet Another Network Simulator (YANS), ns-2 and ns-3, OPNET , and ROSS (4–8). All of these approaches employ a discrete event simulator (DES...adding NetDMF awareness to the COMPOSER toolkit. Commercial tools, such as OPNET , also maintain a suite of tools for analysis of network simulation...Network Simulator-3 (ns-3). [6] Chang, X. Network Simulations with OPNET . In Winter Simulation Conference, 1999. [7] Khosa, I.; Haider, U.; Mosood, H

  11. Homoclinic chaos in axisymmetric Bianchi-IX cosmological models with an ad hoc quantum potential

    SciTech Connect

    Correa, G. C.; Stuchi, T. J.; Joras, S. E.

    2010-04-15

    In this work we study the dynamics of the axisymmetric Bianchi-IX cosmological model with a term of quantum potential added. As it is well known, this class of Bianchi-IX models is homogeneous and anisotropic with two scale factors, A(t) and B(t), derived from the solution of Einstein's equation for general relativity. The model we use in this work has a cosmological constant and the matter content is dust. To this model we add a quantum-inspired potential that is intended to represent short-range effects due to the general relativistic behavior of matter in small scales and play the role of a repulsive force near the singularity. We find that this potential restricts the dynamics of the model to positive values of A(t) and B(t) and alters some qualitative and quantitative characteristics of the dynamics studied previously by several authors. We make a complete analysis of the phase space of the model finding critical points, periodic orbits, stable/unstable manifolds using numerical techniques such as Poincare section, numerical continuation of orbits, and numerical globalization of invariant manifolds. We compare the classical and the quantum models. Our main result is the existence of homoclinic crossings of the stable and unstable manifolds in the physically meaningful region of the phase space [where both A(t) and B(t) are positive], indicating chaotic escape to inflation and bouncing near the singularity.

  12. A Time-Slotted On-Demand Routing Protocol for Mobile Ad Hoc Unmanned Vehicle Systems

    SciTech Connect

    Hope Forsmann; Robert Hiromoto; John Svoboda

    2007-04-01

    The popularity of UAVs has increased dramatically because of their successful deployment in military operations, their ability to preserve human life, and the continual improvements in wireless communication that serves to increase their capabilities. We believe the usefulness of UAVs would be dramatically increased if formation flight were added to the list of capabilities. Currently, sustained formation flight with a cluster of UAVs has only been achieved with two nodes by the Multi-UAV Testbed at the Massachusetts Institute of Technology. (Park, 2004) Formation flight is a complex operation requiring the ability to adjust the flight patterns on the fly and correct for wind gusts, terrain, and differences in node equipment. All of which increases the amount of inner node communication. Since one of the problems with MANET communication is network congestion, we believe a first step towards formation flight can be made through improved inner node communication. We have investigated current communication routing protocols and developed an altered hybrid routing protocol in order to provide communication with less network congestion.

  13. A maintenance scheme of communication link in mobile robot ad hoc networks based on potential field

    NASA Astrophysics Data System (ADS)

    Jiang, Hong; Jin, WenPing; Yang, GyoYing; Li, LeiMin

    2007-12-01

    Maintaining communication link in mobile robot networks between task robots and a control center is very important in some urgent application occasions such as remote danger detections. To offer a reliable multi-hop communication link, a link maintaining scheme based on artificial potential field is presented. The scheme is achieved by a task robot and communication relay ones. The task robot performs predefined tasks, and relay ones are simple robots which form a communication relay chain. When robots move towards destination in formation, a kind of attractive force created by communication quality is added to traditional potential field, and relay robots follow the task robot and automatically stop at adequate locations to form a relay chain from the control station to the task robot. In order to increase relay usage efficiency, when some relays are replaced by other short cut relays, the redundant relays can be reused by initiating another moving toward specified location. Simulation results show that the scheme can provide a reliable multi-hop communication link, and that the communication connection can be obtained through minimal number of relays.

  14. Simulator and location-aware routing protocol for mobile ad hoc acoustic networks of AUVs

    NASA Astrophysics Data System (ADS)

    Carlson, Edward A.

    Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the flooding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric. This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was

  15. Ad Hoc Influenza Vaccination During Years of Significant Antigenic Drift in a Tropical City With 2 Seasonal Peaks

    PubMed Central

    Wong, Martin C.S.; Nelson, E. Anthony S.; Leung, Czarina; Lee, Nelson; Chan, Martin C.W.; Choi, Kin Wing; Rainer, Timothy H.; Cheng, Frankie W.T.; Wong, Samuel Y.S.; Lai, Christopher K.C.; Lam, Bosco; Cheung, Tak Hong; Leung, Ting Fan; Chan, Paul K.S.

    2016-01-01

    Abstract We evaluated the acceptability of an additional ad hoc influenza vaccination among the health care professionals following seasons with significant antigenic drift. Self-administered, anonymous surveys were performed by hard copy questionnaires in public hospitals, and by an on-line platform available to all healthcare professionals, from April 1st to May 31st, 2015. A total of 1290 healthcare professionals completed the questionnaires, including doctors, nurses, and allied health professionals working in both the public and private systems. Only 31.8% of participating respondents expressed an intention to receive the additional vaccine, despite that the majority of them agreed or strongly agreed that it would bring benefit to the community (88.9%), save lives (86.7%), reduce medical expenses (76.3%), satisfy public expectation (82.8%), and increase awareness of vaccination (86.1%). However, a significant proportion expressed concern that the vaccine could disturb the normal immunization schedule (45.5%); felt uncertain what to do in the next vaccination round (66.0%); perceived that the summer peak might not occur (48.2%); and believed that the summer peak might not be of the same virus (83.5%). Furthermore, 27.8% of all respondents expected that the additional vaccination could weaken the efficacy of previous vaccinations; 51.3% was concerned about side effects; and 61.3% estimated that there would be a low uptake rate. If the supply of vaccine was limited, higher priority groups were considered to include the elderly aged ≥65 years with chronic medical conditions (89.2%), the elderly living in residential care homes (87.4%), and long-stay residents of institutions for the disabled (80.7%). The strongest factors associated with accepting the additional vaccine included immunization with influenza vaccines in the past 3 years, higher perceived risk of contracting influenza, and higher perceived severity of the disease impact. The acceptability to an

  16. The Effects of Two Normative Structural Interventions on Established and Ad Hoc Groups: Implications for the Improvement of Decision Making Effectiveness. Paper No. 497.

    ERIC Educational Resources Information Center

    Pasmore, William A.; And Others

    This paper describes a study that compared the use of consensual, nominal, and conventional decision-making techniques in established and ad hoc groups. The impact of the structural interventions on group decision quality and group attitudes is examined and the appropriateness of the techniques in various situation is discussed. Findings of the…

  17. Modern Foreign Language Teachers--Don't Leave Those Kids Alone! Linguistic-Cultural "Give and Take" in an Ad-Hoc Tutoring Scheme

    ERIC Educational Resources Information Center

    Leroy, Norah

    2017-01-01

    This paper addresses the theme of social inclusion through language learning. The focus is on an ad-hoc tutoring scheme set up between newly arrived British migrant pupils and French monolingual pupils in a small secondary school in the south-west of France. Though the original objective of this tutoring scheme was to improve the English skills of…

  18. Report on Counseling Evaluation Guidelines Developed by the Ad Hoc Counseling Task Force and Endorsed by the Illinois Community College Board.

    ERIC Educational Resources Information Center

    Illinois Community Coll. Board, Springfield.

    Three years of cooperative effort by participating Illinois community colleges and the Ad Hoc Counseling Task Force resulted in the 1977 approval, by the Illinois Community College Board (ICCB), of a position paper on comprehensive counseling services and in the endorsement of guidelines in four student service areas. The ICCB supports counseling…

  19. Extended Virtual Spring Mesh (EVSM): The Distributed Self-Organizing Mobile Ad Hoc Network for Area Exploration

    SciTech Connect

    Kurt Derr

    2011-12-01

    Mobile Ad hoc NETworks (MANETs) are distributed self-organizing networks that can change locations and configure themselves on the fly. This paper focuses on an algorithmic approach for the deployment of a MANET within an enclosed area, such as a building in a disaster scenario, which can provide a robust communication infrastructure for search and rescue operations. While a virtual spring mesh (VSM) algorithm provides scalable, self-organizing, and fault-tolerant capabilities required by aMANET, the VSM lacks the MANET's capabilities of deployment mechanisms for blanket coverage of an area and does not provide an obstacle avoidance mechanism. This paper presents a new technique, an extended VSM (EVSM) algorithm that provides the following novelties: (1) new control laws for exploration and expansion to provide blanket coverage, (2) virtual adaptive springs enabling the mesh to expand as necessary, (3) adapts to communications disturbances by varying the density and movement of mobile nodes, and (4) new metrics to assess the performance of the EVSM algorithm. Simulation results show that EVSM provides up to 16% more coverage and is 3.5 times faster than VSM in environments with eight obstacles.

  20. Dynamic cooperative clustering based power assignment: network capacity and lifetime efficient topology control in cooperative ad hoc networks.

    PubMed

    Li, Xiao-Hong; Xiao, Ling; Wang, Dong

    2014-01-01

    Cooperative communication (CC) is used in topology control as it can reduce the transmission power and expand the transmission range. However, all previous research on topology control under the CC model focused on maintaining network connectivity and minimizing the total energy consumption, which would lead to low network capacity, transmission interruption, or even network paralysis. Meanwhile, without considering the balance of energy consumption in the network, it would reduce the network lifetime and greatly affect the network performance. This paper tries to solve the above problems existing in the research on topology control under the CC model by proposing a power assignment (DCCPA) algorithm based on dynamic cooperative clustering in cooperative ad hoc networks. The new algorithm clusters the network to maximize network capacity and makes the clusters communicate with each other by CC. To reduce the number of redundant links between clusters, we design a static clustering method by using Kruskal algorithm. To maximize the network lifetime, we also propose a cluster head rotating method which can reach a good tradeoff between residual energy and distance for the cluster head reselection. Experimental results show that DCCPA can improve 80% network capacity with Cooperative Bridges algorithm; meanwhile, it can improve 20% network lifetime.

  1. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks

    PubMed Central

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-01-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors’ best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well. PMID:27809285

  2. On interaction between MAC and transport layers for media streaming in 802.11 ad hoc networks

    NASA Astrophysics Data System (ADS)

    Nahm, Kitae; Helmy, Ahmed; Kuo, C.-C. Jay

    2004-10-01

    We examine the validity of TCP-friendliness and the utility of equation-based congestion control as a mean for the media streaming service in 802.11 multi-hop networks. Our investigation is motivated by the recent findings of the bandwidth-delay product of 802.11 multi-hop networks via intensive computer simulations. We show that TCP behavior in 802.11 multi-hop networks is generally inefficient and unstable because the standard TCP is too aggressive considering the low bandwidth-delay product of 802.11 networks. We introduce the concept of the `fractional window' mechanism (which resembles the stop-and-go protocol) for TCP, and show that the modified TCP is more stable and efficient while outperforming the legacy TCP in 802.11-based ad hoc networks. Finally, we show that many of the typical problems of TCP protocol (performance, network fairness, and TCP-friendliness) in 802.11 networks can be solved simply by increasing the bandwidth-delay product of 802.11 networks without any TCP modification. Based on this observation, we conclude that the assumption of the ideal steady-state TCP behavior is generally invalid in 802.11 multi-hop networking environment, and that congestion control based on TCP-friendly equation can hardly provide TCP-fair throughput and smoothness in 802.11 multi-hop networking environment.

  3. Dynamic Cooperative Clustering Based Power Assignment: Network Capacity and Lifetime Efficient Topology Control in Cooperative Ad Hoc Networks

    PubMed Central

    Xiao, Ling

    2014-01-01

    Cooperative communication (CC) is used in topology control as it can reduce the transmission power and expand the transmission range. However, all previous research on topology control under the CC model focused on maintaining network connectivity and minimizing the total energy consumption, which would lead to low network capacity, transmission interruption, or even network paralysis. Meanwhile, without considering the balance of energy consumption in the network, it would reduce the network lifetime and greatly affect the network performance. This paper tries to solve the above problems existing in the research on topology control under the CC model by proposing a power assignment (DCCPA) algorithm based on dynamic cooperative clustering in cooperative ad hoc networks. The new algorithm clusters the network to maximize network capacity and makes the clusters communicate with each other by CC. To reduce the number of redundant links between clusters, we design a static clustering method by using Kruskal algorithm. To maximize the network lifetime, we also propose a cluster head rotating method which can reach a good tradeoff between residual energy and distance for the cluster head reselection. Experimental results show that DCCPA can improve 80% network capacity with Cooperative Bridges algorithm; meanwhile, it can improve 20% network lifetime. PMID:24757413

  4. Dynamic Key Management Schemes for Secure Group Access Control Using Hierarchical Clustering in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsaur, Woei-Jiunn; Pai, Haw-Tyng

    2008-11-01

    The applications of group computing and communication motivate the requirement to provide group access control in mobile ad hoc networks (MANETs). The operation in MANETs' groups performs a decentralized manner and accommodated membership dynamically. Moreover, due to lack of centralized control, MANETs' groups are inherently insecure and vulnerable to attacks from both within and outside the groups. Such features make access control more challenging in MANETs. Recently, several researchers have proposed group access control mechanisms in MANETs based on a variety of threshold signatures. However, these mechanisms cannot actually satisfy MANETs' dynamic environments. This is because the threshold-based mechanisms cannot be achieved when the number of members is not up to the threshold value. Hence, by combining the efficient elliptic curve cryptosystem, self-certified public key cryptosystem and secure filter technique, we construct dynamic key management schemes based on hierarchical clustering for securing group access control in MANETs. Specifically, the proposed schemes can constantly accomplish secure group access control only by renewing the secure filters of few cluster heads, when a cluster head joins or leaves a cross-cluster. In such a new way, we can find that the proposed group access control scheme can be very effective for securing practical applications in MANETs.

  5. Design and Analysis of A Beacon-Less Routing Protocol for Large Volume Content Dissemination in Vehicular Ad Hoc Networks.

    PubMed

    Hu, Miao; Zhong, Zhangdui; Ni, Minming; Baiocchi, Andrea

    2016-11-01

    Large volume content dissemination is pursued by the growing number of high quality applications for Vehicular Ad hoc NETworks(VANETs), e.g., the live road surveillance service and the video-based overtaking assistant service. For the highly dynamical vehicular network topology, beacon-less routing protocols have been proven to be efficient in achieving a balance between the system performance and the control overhead. However, to the authors' best knowledge, the routing design for large volume content has not been well considered in the previous work, which will introduce new challenges, e.g., the enhanced connectivity requirement for a radio link. In this paper, a link Lifetime-aware Beacon-less Routing Protocol (LBRP) is designed for large volume content delivery in VANETs. Each vehicle makes the forwarding decision based on the message header information and its current state, including the speed and position information. A semi-Markov process analytical model is proposed to evaluate the expected delay in constructing one routing path for LBRP. Simulations show that the proposed LBRP scheme outperforms the traditional dissemination protocols in providing a low end-to-end delay. The analytical model is shown to exhibit a good match on the delay estimation with Monte Carlo simulations, as well.

  6. Services oriented architectures and rapid deployment of ad-hoc health surveillance systems: lessons from Katrina relief efforts.

    PubMed

    Mirhaji, Parsa; Casscells, S Ward; Srinivasan, Arunkumar; Kunapareddy, Narendra; Byrne, Sean; Richards, David Mark; Arafat, Raouf

    2006-01-01

    During the Hurricane Katrina relief efforts, a new city was born overnight within the City of Houston to provide accommodation and health services for thousands of evacuees deprived of food, rest, medical attention, and sanitation. The hurricane victims had been exposed to flood water, toxic materials, physical injury, and mental stress. This scenario was an invitation for a variety of public health hazards, primarily infectious disease outbreaks. Early detection and monitoring of morbidity and mortality among evacuees due to unattended health conditions was an urgent priority and called for deployment of real-time surveillance to collect and analyze data at the scene, and to enable and guide appropriate response and planning activities. The University of Texas Health Science Center at Houston (UTHSC) and the Houston Department of Health and Human Services (HDHHS) deployed an ad hoc surveillance system overnight by leveraging Internet-based technologies and Services Oriented Architecture (SOA). The system was post-coordinated through the orchestration of Web Services such as information integration, natural language processing, syndromic case finding, and online analytical processing (OLAP). Here we will report the use of Internet-based and distributed architectures in providing timely, novel, and customizable solutions on demand for unprecedented events such as natural disasters.

  7. A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks

    PubMed Central

    Mezher, Ahmad Mohamad; Igartua, Mónica Aguilar; de la Cruz Llopis, Luis J.; Segarra, Esteve Pallarès; Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Forné, Jordi; Gargallo, Emilio Sanvicente

    2015-01-01

    The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc.) could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers) rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs) has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic.Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs. PMID:25897496

  8. A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks.

    PubMed

    Mezher, Ahmad Mohamad; Igartua, Mónica Aguilar; de la Cruz Llopis, Luis J; Pallarès Segarra, Esteve; Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Forné, Jordi; Sanvicente Gargallo, Emilio

    2015-04-17

    The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc.) could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers) rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs) has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic. Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs.

  9. Ad Hoc Rural Regionalism

    ERIC Educational Resources Information Center

    Hamin, Elisabeth M.; Marcucci, Daniel J.

    2008-01-01

    A new regionalism has been much documented and researched for metropolitan areas; this article documents that there is a new rural regionalism as well. In the United States, these groups appear most likely to emerge in areas that are challenged by outcomes characterizing globalization's effects on the rural condition: namely, exurban or…

  10. Ad Hoc Rural Regionalism

    ERIC Educational Resources Information Center

    Hamin, Elisabeth M.; Marcucci, Daniel J.

    2008-01-01

    A new regionalism has been much documented and researched for metropolitan areas; this article documents that there is a new rural regionalism as well. In the United States, these groups appear most likely to emerge in areas that are challenged by outcomes characterizing globalization's effects on the rural condition: namely, exurban or…

  11. Adaptive Wireless Ad-hoc Sensor Networks for Long-term and Event-oriented Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Remmler, Paul; Schaedler, Martin; Schima, Robert; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2015-04-01

    Ecosystems are often characterized by their high heterogeneity, complexity and dynamic. Hence, single point measurements are often not sufficient for their complete representation. The application of wireless sensor networks in terrestrial and aquatic environmental systems offer significant benefits as a better consideration to the local test conditions, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate. Another advantage of wireless ad-hoc sensor networks is their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, individual point measurements with a sensor are significantly improved by measuring at several points continuously. In this work a concept and realization for Long-term ecosystem research is given in the field monitoring of micrometeorology and soil parameters for the interaction of biotic and abiotic processes. This long term analyses are part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Regarding to the adaptive behavior of the network, also a mobile version was developed to overcome the lack of information of temporally and spatially fixed measurements for the detection and recording of highly dynamic or time limited processes. First results of different field campaigns are given to present the potentials and limitations of this application in environmental science, especially for the monitoring of the interaction of biotic and abiotic processes, soil-atmosphere interaction and the validation of remote sensing data.

  12. The Kuroshio Extension low-frequency variability analyzed with altimeter data through an ad hoc composite index

    NASA Astrophysics Data System (ADS)

    Pierini, Stefano; Gentile, Vittorio; de Ruggiero, Paola; Pietranera, Luca

    2017-04-01

    The Kuroshio Extension (KE) low-frequency variability (LFV) is analyzed with the satellite altimeter data distributed by AVISO from January 1993 to November 2015 through a new ad hoc composite index [1] that links the mean latitudinal position L of the KE jet and an integrated wavelet amplitude A measuring the high-frequency variability (HFV) of the KE path. This approach allows one to follow the KE evolution as an orbit in the (L,A) plane, as typically done in dynamical systems theory. Three intervals, I1 (1993-1998), I2 (1998-2006) and I3 (2006-November 2015) are separately analyzed also with sea surface height (SSH) maps. In I1 and I3, L and A are mostly anti-correlated and a recharging phase (characterized by a weak convoluted jet experiencing a rapid increase of the HFV) begins when negative SSH anomalies, remotely generated by the Pacific Decadal Oscillation, reach the KE region. On the other hand, in I2 the KE evolution is described by a hysteresis loop: this starts with a weak jet state followed by a recharging phase leading, in turn, to a persistent two-meander state, to its progressive and rapid erosion and, eventually, to the reestablishment of a weak jet state. This loop is found to correspond quite closely to the highly nonlinear intrinsic relaxation oscillation obtained in numerical process studies [1,2]. This supports the hypothesis that the KE LFV may have been controlled, during I2, by an intrinsic oceanic mode of variability. [1] Pierini S., 2015. J. Climate, 28, 5873-5881. [2] Pierini S., 2006. J. Phys. Oceanogr., 36, 1605-1625.

  13. Adaptive Wireless Ad-hoc Sensor Networks for Long-term and Event-oriented Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Bumberger, Jan; Mollenhauer, Hannes; Remmler, Paul; Chirila, Andrei Marian; Mollenhauer, Olaf; Hutschenreuther, Tino; Toepfer, Hannes; Dietrich, Peter

    2016-04-01

    Ecosystems are often characterized by their high heterogeneity, complexity and dynamic. Hence, single point measurements are often not sufficient for their complete representation. The application of wireless sensor networks in terrestrial and aquatic environmental systems offer significant benefits as a better consideration to the local test conditions, due to the simple adjustment of the sensor distribution, the sensor types and the sample rate. Another advantage of wireless ad-hoc sensor networks is their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. In addition, individual point measurements with a sensor are significantly improved by measuring at several points continuously. In this work a concept and realization for Long-term ecosystem research is given in the field monitoring of micrometeorology and soil parameters for the interaction of biotic and abiotic processes. This long term analyses are part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. Regarding to the adaptive behavior of the network, also a mobile version was developed to overcome the lack of information of temporally and spatially fixed measurements for the detection and recording of highly dynamic or time limited processes. First results of different field campaigns are given to present the potentials and limitations of this application in environmental science, especially for the monitoring of the interaction of biotic and abiotic processes, soil-atmosphere interaction and the validation of remote sensing data.

  14. 76 FR 3932 - Fifty-Third Meeting: RTCA Special Committee 186: Automatic Dependent Surveillance-Broadcast (ADS-B)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ... Federal Aviation Administration Fifty-Third Meeting: RTCA Special Committee 186: Automatic Dependent... Special Committee 186: Automatic Dependent Surveillance--Broadcast (ADS-B) meeting. SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 186: Automatic Dependent...

  15. Comparison of two commonly practiced atropinization regimens in acute organophosphorus and carbamate poisoning, doubling doses vs. ad hoc: a prospective observational study.

    PubMed

    Perera, P M S; Shahmy, S; Gawarammana, I; Dawson, A H

    2008-06-01

    There is a wide variation and lack of evidence in current recommendations for atropine dosing schedules leading to subsequent variation in clinical practice. Therefore, we sought to examine the safety and effectiveness of a titrated vs. ad hoc atropine treatment regimen in a cohort of patients with acute cholinesterase inhibitor pesticide poisoning. A prospective cohort study was conducted in three district secondary referral hospitals in Sri Lanka using a structured data collection form that collected details of clinical symptoms and outcomes of cholinesterase inhibitor pesticide poisoning, atropine doses, and signs of atropinization. We compared two hospitals that used a titrated dosing protocol based on a structured monitoring sheet for atropine infusion with another hospital using an ad hoc regime. During the study, 272 symptomatic patients with anticholinesterase poisoning requiring atropine were admitted to the three hospitals. Outcomes of death and ventilation were analyzed for all patients, 226 patients were prospectively assessed for atropine toxicity. At baseline, patients in the titrated dose cohort had clinical signs consistent with greater toxicity. This in part may be due to ingestion of more toxic organophosphates. They received less pralidoxime and atropine, and were less likely to develop features of atropine toxicity, such as delirium (1% vs. 17%), hallucinations (1% vs. 35%), or either (1% vs. 35%) and need for patient restraint (3% vs. 48%) compared with the ad hoc dose regime. After adjusting for the pesticides ingested, there was no difference in mortality and ventilatory rates between protocols. Ad hoc high dose atropine regimens are associated with more frequent atropine toxicity without any obvious improvement in patient outcome compared with doses titrated to clinical effect. Atropine doses should be titrated against response and toxicity. Further education and the use of a structured monitoring sheet may assist in more appropriate

  16. Clinician Ratings of Interpreter Mediated Visits in Underserved Primary Care Settings with Ad hoc, In-person Professional, and Video Conferencing Modes

    PubMed Central

    Nápoles, Anna M.; Santoyo-Olsson, Jasmine; Karliner, Leah S.; O’Brien, Helen; Gregorich, Steven E.; Pérez-Stable, Eliseo J.

    2013-01-01

    Language interpretation ameliorates health disparities among underserved limited English-proficient patients, yet few studies have compared clinician satisfaction with these services. Self-administered clinician post-visit surveys compared the quality of interpretation and communication, visit satisfaction, degree of patient engagement, and cultural competence of visits using untrained people acting as interpreters (ad hoc), in-person professional, or video conferencing professional interpretation for 283 visits. Adjusting for clinician and patient characteristics, the quality of interpretation of in-person and video conferencing modes were rated similarly (OR=1.79; 95% CI 0.74, 4.33). The quality of in-person (OR=5.55; 95% CI 1.50, 20.51) and video conferencing (OR=3.10; 95% CI 1.16, 8.31) were rated higher than ad hoc interpretation. Self-assessed cultural competence was better for in-person versus video conferencing interpretation (OR=2.32; 95% CI 1.11, 4.86). Video conferencing interpretation increases access without compromising quality, but cultural nuances may be better addressed by in-person interpreters. Professional interpretation is superior to ad hoc (OR=4.15; 95% CI 1.43, 12.09). PMID:20173271

  17. Development of Innovative and Inexpensive Optical Sensors in Wireless Ad-hoc Sensor Networks for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Mollenhauer, Hannes; Schima, Robert; Assing, Martin; Mollenhauer, Olaf; Dietrich, Peter; Bumberger, Jan

    2015-04-01

    Due to the heterogeneity and dynamic of ecosystems, the observation and monitoring of natural processes necessitate a high temporal and spatial resolution. This also requires inexpensive and adaptive measurements as well as innovative monitoring strategies. To this end, the application of ad-hoc wireless sensor networks holds the potential of creating an adequate monitoring platform. In order to achieve a comprehensive monitoring in space and time with affordability, it is necessary to reduce the sensor costs. Common investigation methods, especially with regard to vegetation processes, are based on optical measurements. In particular, different wavelengths correspond to specific properties of the plants and preserve the possibility to derive information about the ecosystem, e.g. photosynthetic performance or nutrient content. In this context, photosynthetically active radiation (PAR) sensors and hyperspectral sensors are in major use. This work aims the development, evaluation and application of inexpensive but high performance optical sensors for the implementation in wireless sensor networks. Photosynthetically active radiation designates the spectral range from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. PAR sensors enable the detection of the reflected solar light of the vegetation in the whole PAR wave band. The amount of absorption indicates photosynthetic activity of the plant, with good approximation. Hyperspectral sensors observe specific parts or rather distinct wavelengths of the solar light spectrum and facilitate the determination of the main pigment classes, e.g. Chlorophyll, Carotenoid and Anthocyanin. Due to the specific absorption of certain pigments, a characteristic spectral signature can be seen in the visible part of the electromagnetic spectrum, known as narrow-band peaks. In an analogous manner, also the presence and concentration of different nutrients cause a characteristic spectral

  18. Ad-hoc and context-dependent adjustments of selective attention in conflict control: an ERP study with visual probes.

    PubMed

    Nigbur, R; Schneider, J; Sommer, W; Dimigen, O; Stürmer, B

    2015-02-15

    Cognitive conflict control in flanker tasks has often been described using the zoom-lens metaphor of selective attention. However, whether and how selective attention - in terms of suppression and enhancement - operates in this context has remained unclear. To examine the dynamic interplay of selective attention and cognitive control we used electrophysiological measures and presented task-irrelevant visual probe stimuli at foveal, parafoveal, and peripheral display positions. Target-flanker congruency varied either randomly from trial to trial (mixed-block) or block-wise (fixed-block) in order to induce reactive versus proactive control modes, respectively. Three EEG measures were used to capture ad-hoc adjustments within trials as well as effects of context-based predictions: the N1 component of the visual evoked potential (VEP) to probes, the VEP to targets, and the conflict-related midfrontal N2 component. Results from probe-VEPs indicate that enhanced processing of the foveal target rather than suppression of the peripheral flankers supports interference control. In incongruent mixed-block trials VEPs were larger to probes near the targets. In the fixed-blocks probe-VEPs were not modulated, but contrary to the mixed-block the preceding target-related VEP was affected by congruency. Results of the control-related N2 reveal largest amplitudes in the unpredictable context, which did not differentiate for stimulus and response incongruency. In contrast, in the predictable context, N2 amplitudes were reduced overall and differentiated between stimulus and response incongruency. Taken together these results imply that predictability alters interference control by a reconfiguration of stimulus processing. During unpredictable sequences participants adjust their attentional focus dynamically on a trial-by-trial basis as reflected in congruency-dependent probe-VEP-modulation. This reactive control mode also elicits larger N2 amplitudes. In contrast, when task demands

  19. A Security Solution for IEEE 802.11's Ad-hoc Mode:Password-Authentication and Group Diffie-Hellman Key Exchange

    SciTech Connect

    Emmanuel, Bresson; Olivier, Chevassut; David, Pointcheval

    2005-10-01

    The IEEE 802 standards ease the deployment of networkinginfrastructures and enable employers to accesscorporate networks whiletraveling. These standards provide two modes of communication calledinfrastructure and ad-hoc modes. A security solution for the IEEE802.11's infrastructure mode took several years to reach maturity andfirmware are still been upgraded, yet a solution for the ad-hoc modeneeds to be specified. The present paper is a first attempt in thisdirection. It leverages the latest developments in the area ofpassword-based authentication and (group) Diffie-Hellman key exchange todevelop a provably-secure key-exchange protocol for IEEE 802.11's ad-hocmode. The protocol allows users to securely join and leave the wirelessgroup at time, accommodates either a single-shared password orpairwise-shared passwords among the group members, or at least with acentral server; achieves security against dictionary attacks in theideal-hash model (i.e. random-oracles). This is, to the best of ourknowledge, the first such protocol to appear in the cryptographicliterature.

  20. Ad Hoc Networking for Unmanned Ground Vehicles: Design and Evaluation at Command, Control, Communications, Intelligence, Surveillance and Reconnaissance On-the-Move

    DTIC Science & Technology

    2006-11-01

    software components used in the ad hoc nodes for the C4ISR OTM experiment were OLSRD, an open-source proactive MANET routing software, and OpenVPN , an...developed by Mike Baker (openwrt.org). 6OpenVPN is a trademark of OpenVPN Solutions LLC. 6 Secure communications in the MANET are achieved with...encryption provided by Wired Equivalent Privacy (WEP) and OpenVPN . The WEP protocol, which is part of the IEEE 802.11 wireless networking standard

  1. Modern foreign language teachers - don't leave those kids alone! Linguistic-cultural "give and take" in an ad-hoc tutoring scheme

    NASA Astrophysics Data System (ADS)

    Leroy, Norah

    2017-08-01

    This paper addresses the theme of social inclusion through language learning. The focus is on an ad-hoc tutoring scheme set up between newly arrived British migrant pupils and French monolingual pupils in a small secondary school in the south-west of France. Though the original objective of this tutoring scheme was to improve the English skills of the younger pupils, feedback reports indicated that it also had a positive impact on the relationship between the British migrant pupils and their French peers. Teachers believed that those involved participated more fully in class, and appeared more self-assured and generally happy thanks to the interpersonal relationships this scheme helped to forge. This study demonstrates the necessity of analysing the socio-cultural context migrants may find themselves in, in order to identify potential challenges. The ad-hoc tutoring scheme described here is an example of how language learning can support the integration and inclusion of "new generation" migrants into everyday school life.

  2. Comparison of operator radiation exposure with optimized radiation protection devices during coronary angiograms and ad hoc percutaneous coronary interventions by radial and femoral routes.

    PubMed

    Brasselet, Camille; Blanpain, Thierry; Tassan-Mangina, Sophie; Deschildre, Alain; Duval, Sébastien; Vitry, Fabien; Gaillot-Petit, Nathalie; Clément, Jean Paul; Metz, Damien

    2008-01-01

    Although underestimated by interventional cardiologists for a long time, radiation exposure of operators and patients is currently a major concern. The objective of the present operator-blinded registry was to compare related-peripheral arterial route radiation exposure of operators. During 420 consecutive coronary angiograms (CAs) and percutaneous coronary interventions (PCIs), four interventional cardiologists were blindly screened. Radiation exposures were assessed using electronic personal dosimeters. Protection of operator was ensured using a lead apron, low leaded flaps, and leaded glass. Radiation exposure of operators was significantly higher using the radial route when compared with the femoral route for both CAs and CAs followed by ad hoc PCIs: 29.0 [1.0-195.0] microSv vs. 13.0 [1.0-164.0] microSv; P < 0.0001 and 69.5 [4.0-531.0] microSv vs. 41.0 [2.0-360.0] microSv; P = 0.018, respectively. Similarly, radiation exposure of patients was significantly higher using the radial route when compared with the femoral route for both CAs and CAs followed by ad hoc PCIs. Moreover, procedural durations and fluoroscopy times were significantly higher throughout the radial route. Although the radial route decreases peripheral arterial complication rates, increased radiation exposure of operators despite extensive use of specific protection devices is currently a growing problem for the interventional cardiologist health. Radial route indication should be promptly reconsidered in the light of the present findings.

  3. Modern foreign language teachers - don't leave those kids alone! Linguistic-cultural "give and take" in an ad-hoc tutoring scheme

    NASA Astrophysics Data System (ADS)

    Leroy, Norah

    2017-07-01

    This paper addresses the theme of social inclusion through language learning. The focus is on an ad-hoc tutoring scheme set up between newly arrived British migrant pupils and French monolingual pupils in a small secondary school in the south-west of France. Though the original objective of this tutoring scheme was to improve the English skills of the younger pupils, feedback reports indicated that it also had a positive impact on the relationship between the British migrant pupils and their French peers. Teachers believed that those involved participated more fully in class, and appeared more self-assured and generally happy thanks to the interpersonal relationships this scheme helped to forge. This study demonstrates the necessity of analysing the socio-cultural context migrants may find themselves in, in order to identify potential challenges. The ad-hoc tutoring scheme described here is an example of how language learning can support the integration and inclusion of "new generation" migrants into everyday school life.

  4. 78 FR 1196 - Codex Alimentarius Commission: Meeting of the Ad Hoc Codex Intergovernmental Task Force on Animal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-08

    ...; ] DEPARTMENT OF AGRICULTURE Food Safety and Inspection Service Codex Alimentarius Commission: Meeting of the Ad... agenda items and draft United States (U.S.) positions that will be discussed at the 7th Session of the...

  5. Public affairs committee actions

    NASA Astrophysics Data System (ADS)

    The AGU Public Affairs Committee will create an ad hoc committee to consider possible AGU position statements concerning the effects of nuclear war.The action was taken at the May 31, 1983, meeting of the Committee at the AGU Spring Meeting in Baltimore. Present were Carroll Ann Hodges, Chairman, and members Thomas J. Ahrens, David Cauffman, Jared Cohon, Stamatios Krimigis, Robert Murphy, Raymond Roble, and George Shaw. Also attending were the current Congressional Fellow Arthur Weissman and SPR—Cosmic Rays Section Secretary Miriam Forman.

  6. Federal Advisory Committees: An Overview

    DTIC Science & Technology

    2009-04-16

    initiating a tradition of presidential use of outside expertise when, in 1794 , he appointed an ad hoc group of commissioners to investigate the Whiskey ... Rebellion .7 Since 1842, Congress has legislated control over federal advisory bodies — mostly by limiting funding and committee member pay. In 1842...reports aggregated advisory body information to Congress annually.12 7 " Whiskey Insurrection in

  7. In search for evidence: combining ad hoc survey, monitoring, and modeling to estimate the potential and actual impact of ground level ozone on forests in Trentino (Northern Italy).

    PubMed

    Gottardini, Elena; Cristofolini, Fabiana; Cristofori, Antonella; Ferretti, Marco

    2017-09-27

    A 5-year project was carried out over the period 2007-2011 to estimate the potential and actual ozone effect on forests in Trentino, Northern Italy (6207 km(2)) (Ozone EFFORT). The objective was to provide explicit answers to three main questions: (i) is there a potential risk placed by ozone to vegetation? (ii) are there specific ozone symptoms on vegetation, and are they related to ozone levels? (iii) are there ozone-related effects on forest health and growth? Different methods and techniques were adopted as follows: monitoring ozone levels, ad hoc field survey for symptoms on vegetation and chlorophyll-related measurements, modeling to upscale ozone measurements, ozone flux estimation, statistical analysis, and modeling to detect whether a significant effect attributable to ozone exists. Ozone effects were assessed on an ad hoc-introduced bioindicator, on spontaneous woody species, and on forest trees. As for question (i), the different ozone-risk critical levels for both exposure and stomatal flux were largely exceeded in Trentino, evidencing a potentially critical situation for vegetation. As for question (ii), specific ozone foliar symptoms related to ozone exposure levels were observed on the introduced supersensitive Nicotiana tabacum L. cv Bel-W3 and on the spontaneous, ozone-sensitive Viburnum lantana L., but not on other 33 species surveyed in the field studies. Regarding question (iii), statistical analyses on forest health (in terms of defoliation) and growth (in terms of basal area increment) measured at 15 forest monitoring plots and tree rings (at one site) revealed no significant relationship with ozone exposure and flux. Instead, a set of factors related to biotic and abiotic causes, foliar nutrients, age, and site were identified as the main drivers of forest health and growth. In conclusion, while ozone levels and fluxes in the investigated region were much higher than current critical levels, evidence of impact on vegetation-and on forest

  8. Satellites for distress alerting and locating: Report by Interagency Committee for Search and Rescue Ad Hoc Working Group

    NASA Technical Reports Server (NTRS)

    Ehrlich, E.

    1976-01-01

    The background behind the congressional legislation that led to the requirement for the Emergency Locator Transmitter (ELT) and the Emergency Position-Indicating Radio Beacon (EPIRB) to be installed on certain types of aircraft and inspected marine vessels respectively is discussed. The DAL problem is discussed for existing ELT and EPIRB equipped aircraft and ships. It is recognized that the DAL requirement for CONUS and Alaska and the maritime regions are not identical. In order to address the serious DAL problem which currently exists in CONUS and Alaska, a low orbiting satellite system evolves as the most viable and cost effective alternative that satisfies the overall SAR system design requirements. A satellite system designed to meet the needs of the maritime regions could be either low orbiting or geostationary. The conclusions drawn from this report support the recommendation to proceed with the implementation of a SAR orbiting satellite system.

  9. The Role of Reading in a Japanese Language Program: A Response to the MLA Ad Hoc Committee's Report (2007)

    ERIC Educational Resources Information Center

    Marcus, Ginger

    2010-01-01

    Reading is defined as a socio-cultural act negotiated between text and reader, and the act of reading is considered to be a cognitive process that involves knowledge not only of symbols/letters, vocabulary and structure, but also of culture. In other words, in order to understand the intentions of the author and to formulate meaning, the second…

  10. Inclusive practices for children and youths with communication disorders. Ad Hoc Committee on Inclusion for students with Communication Disorders.

    PubMed

    1996-01-01

    An array of inclusive service delivery models is recommended for the implementation of services to children and youths with communication disorders. Inclusive practices are intervention services that are based on the unique and specific needs of the individual, and provided in a context that is least restrictive. There are a variety of models through which inclusive practices can be provided, including a direct (pull-out) program, in classroom-based service delivery, community-based models, and consultative interventions. These models should be seen as flexible options that may change depending on student needs. The speech-language pathologist, in collaboration with parents, the student, teachers, support personnel, and administrators, is in the ideal position to decide the model or combination of models that best serves each individual student's communication needs. Implementation of inclusive practices requires consideration of multiple issues, including general education reform, cost effectiveness, and program efficacy. In addition, administrative and school system support, personnel qualifications, staff development, flexible scheduling, and the effects of inclusive practices on all learners need to be considered. At present, available research suggests guarded optimism for the effectiveness of inclusive practices. However, many critical questions have not yet been addressed and additional research is needed to assess the full impact of inclusive practices for students with communication disorders.

  11. [Reporting and grading of complications after urologic surgical procedures: an ad hoc EAU guidelines panel assessment and recommendations].

    PubMed

    Mitropoulos, D; Artibani, W; Graefen, M; Remzi, M; Rouprêt, M; Truss, M

    2013-01-01

    in the number of studies using either standardised criteria or the Clavien-Dindo system. The latter system was not properly used in 72 papers (35.3%). Uniformed reporting of complications after urologic procedures will aid all those involved in patient care and scientific publishing (authors, reviewers, and editors). It will also contribute to the improvement of the scientific quality of papers published in the field of urologic surgery. When reporting the outcomes of urologic procedures, the committee proposes a series of quality criteria. Copyright © 2012 AEU. Published by Elsevier Espana. All rights reserved.

  12. An ultra-wide bandwidth-based range/GPS tight integration approach for relative positioning in vehicular ad hoc networks

    NASA Astrophysics Data System (ADS)

    Shen, Feng; Wayn Cheong, Joon; Dempster, Andrew G.

    2015-04-01

    Relative position awareness is a vital premise for the implementation of emerging intelligent transportation systems, such as collision warning. However, commercial global navigation satellite systems (GNSS) receivers do not satisfy the requirements of these applications. Fortunately, cooperative positioning (CP) techniques, through sharing the GNSS measurements between vehicles, can improve the performance of relative positioning in a vehicular ad hoc network (VANET). In this paper, while assuming there are no obstacles between vehicles, a new enhanced tightly coupled CP technique is presented by adding ultra-wide bandwidth (UWB)-based inter-vehicular range measurements. In the proposed CP method, each vehicle fuses the GPS measurements and the inter-vehicular range measurements. Based on analytical and experimental results, in the full GPS coverage environment, the new tight integration CP method outperforms the INS-aided tight CP method, tight CP method, and DGPS by 11%, 15%, and 24%, respectively; in the GPS outage scenario, the performance improvement achieves 60%, 65%, and 73%, respectively.

  13. Neural methods based on modified reputation rules for detection and identification of intrusion attacks in wireless ad hoc sensor networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2010-04-01

    Determining methods to secure the process of data fusion against attacks by compromised nodes in wireless sensor networks (WSNs) and to quantify the uncertainty that may exist in the aggregation results is a critical issue in mitigating the effects of intrusion attacks. Published research has introduced the concept of the trustworthiness (reputation) of a single sensor node. Reputation is evaluated using an information-theoretic concept, the Kullback- Leibler (KL) distance. Reputation is added to the set of security features. In data aggregation, an opinion, a metric of the degree of belief, is generated to represent the uncertainty in the aggregation result. As aggregate information is disseminated along routes to the sink node(s), its corresponding opinion is propagated and regulated by Josang's belief model. By applying subjective logic on the opinion to manage trust propagation, the uncertainty inherent in aggregation results can be quantified for use in decision making. The concepts of reputation and opinion are modified to allow their application to a class of dynamic WSNs. Using reputation as a factor in determining interim aggregate information is equivalent to implementation of a reputation-based security filter at each processing stage of data fusion, thereby improving the intrusion detection and identification results based on unsupervised techniques. In particular, the reputation-based version of the probabilistic neural network (PNN) learns the signature of normal network traffic with the random probability weights normally used in the PNN replaced by the trust-based quantified reputations of sensor data or subsequent aggregation results generated by the sequential implementation of a version of Josang's belief model. A two-stage, intrusion detection and identification algorithm is implemented to overcome the problems of large sensor data loads and resource restrictions in WSNs. Performance of the twostage algorithm is assessed in simulations of WSN

  14. Ad Hoc Influenza Vaccination During Years of Significant Antigenic Drift in a Tropical City With 2 Seasonal Peaks: A Cross-Sectional Survey Among Health Care Practitioners.

    PubMed

    Wong, Martin C S; Nelson, E Anthony S; Leung, Czarina; Lee, Nelson; Chan, Martin C W; Choi, Kin Wing; Rainer, Timothy H; Cheng, Frankie W T; Wong, Samuel Y S; Lai, Christopher K C; Lam, Bosco; Cheung, Tak Hong; Leung, Ting Fan; Chan, Paul K S

    2016-05-01

    We evaluated the acceptability of an additional ad hoc influenza vaccination among the health care professionals following seasons with significant antigenic drift.Self-administered, anonymous surveys were performed by hard copy questionnaires in public hospitals, and by an on-line platform available to all healthcare professionals, from April 1st to May 31st, 2015. A total of 1290 healthcare professionals completed the questionnaires, including doctors, nurses, and allied health professionals working in both the public and private systems.Only 31.8% of participating respondents expressed an intention to receive the additional vaccine, despite that the majority of them agreed or strongly agreed that it would bring benefit to the community (88.9%), save lives (86.7%), reduce medical expenses (76.3%), satisfy public expectation (82.8%), and increase awareness of vaccination (86.1%). However, a significant proportion expressed concern that the vaccine could disturb the normal immunization schedule (45.5%); felt uncertain what to do in the next vaccination round (66.0%); perceived that the summer peak might not occur (48.2%); and believed that the summer peak might not be of the same virus (83.5%). Furthermore, 27.8% of all respondents expected that the additional vaccination could weaken the efficacy of previous vaccinations; 51.3% was concerned about side effects; and 61.3% estimated that there would be a low uptake rate. If the supply of vaccine was limited, higher priority groups were considered to include the elderly aged ≥65 years with chronic medical conditions (89.2%), the elderly living in residential care homes (87.4%), and long-stay residents of institutions for the disabled (80.7%). The strongest factors associated with accepting the additional vaccine included immunization with influenza vaccines in the past 3 years, higher perceived risk of contracting influenza, and higher perceived severity of the disease impact.The acceptability to an additional ad

  15. Fuzzy Logic-based Intelligent Scheme for Enhancing QoS of Vertical Handover Decision in Vehicular Ad-hoc Networks

    NASA Astrophysics Data System (ADS)

    Azzali, F.; Ghazali, O.; Omar, M. H.

    2017-08-01

    The design of next generation networks in various technologies under the “Anywhere, Anytime” paradigm offers seamless connectivity across different coverage. A conventional algorithm such as RSSThreshold algorithm, that only uses the received strength signal (RSS) as a metric, will decrease handover performance regarding handover latency, delay, packet loss, and handover failure probability. Moreover, the RSS-based algorithm is only suitable for horizontal handover decision to examine the quality of service (QoS) compared to the vertical handover decision in advanced technologies. In the next generation network, vertical handover can be started based on the user’s convenience or choice rather than connectivity reasons. This study proposes a vertical handover decision algorithm that uses a Fuzzy Logic (FL) algorithm, to increase QoS performance in heterogeneous vehicular ad-hoc networks (VANET). The study uses network simulator 2.29 (NS 2.29) along with the mobility traffic network and generator to implement simulation scenarios and topologies. This helps the simulation to achieve a realistic VANET mobility scenario. The required analysis on the performance of QoS in the vertical handover can thus be conducted. The proposed Fuzzy Logic algorithm shows improvement over the conventional algorithm (RSSThreshold) in the average percentage of handover QoS whereby it achieves 20%, 21% and 13% improvement on handover latency, delay, and packet loss respectively. This is achieved through triggering a process in layer two and three that enhances the handover performance.

  16. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK’s Initial Operational Response (IOR)

    PubMed Central

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard

    2017-01-01

    The UK’s Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method (“rinse-wipe-rinse”) for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants. PMID:28152053

  17. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK's Initial Operational Response (IOR).

    PubMed

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard; Chilcott, Robert P

    2017-01-01

    The UK's Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method ("rinse-wipe-rinse") for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants.

  18. Estimating HIV Incidence during Pregnancy and Knowledge of Prevention of Mother-to-Child Transmission with an Ad Hoc Analysis of Potential Cofactors.

    PubMed

    Egbe, Thomas Obinchemti; Tazinya, Rose-Mary Asong; Halle-Ekane, Gregory Edie; Egbe, Eta-Nkongho; Achidi, Eric Akum

    2016-01-01

    We determined the incidence of HIV seroconversion during the second and third trimesters of pregnancy and ad hoc potential cofactors associated with HIV seroconversion after having an HIV-negative result antenatally. We also studied knowledge of PMTCT among pregnant women in seven health facilities in Fako Division, South West Region, Cameroon. During the period between September 12 and December 4, 2011, we recruited a cohort of 477 HIV-negative pregnant women by cluster sampling. Data collection was with a pretested interviewer-administered questionnaire. Sociodemographic information, knowledge of PMTCT, and methods of HIV prevention were obtained from the study population and we did Voluntary Counselling and Testing (VCT) for HIV. The incidence rate of HIV seroconversion during pregnancy was 6.8/100 woman-years. Ninety percent of the participants did not use condoms throughout pregnancy but had a good knowledge of PMTCT of HIV. Only 31.9% of participants knew their HIV status before the booking visit and 33% did not know the HIV status of their partners. The incidence rate of HIV seroconversion in the Fako Division, Cameroon, was 6.8/100 woman-years. No risk factors associated with HIV seroconversion were identified among the study participants because of lack of power to do so.

  19. Estimating HIV Incidence during Pregnancy and Knowledge of Prevention of Mother-to-Child Transmission with an Ad Hoc Analysis of Potential Cofactors

    PubMed Central

    Egbe, Thomas Obinchemti; Tazinya, Rose-Mary Asong; Halle-Ekane, Gregory Edie; Egbe, Eta-Nkongho; Achidi, Eric Akum

    2016-01-01

    Background. We determined the incidence of HIV seroconversion during the second and third trimesters of pregnancy and ad hoc potential cofactors associated with HIV seroconversion after having an HIV-negative result antenatally. We also studied knowledge of PMTCT among pregnant women in seven health facilities in Fako Division, South West Region, Cameroon. Method. During the period between September 12 and December 4, 2011, we recruited a cohort of 477 HIV-negative pregnant women by cluster sampling. Data collection was with a pretested interviewer-administered questionnaire. Sociodemographic information, knowledge of PMTCT, and methods of HIV prevention were obtained from the study population and we did Voluntary Counselling and Testing (VCT) for HIV. Results. The incidence rate of HIV seroconversion during pregnancy was 6.8/100 woman-years. Ninety percent of the participants did not use condoms throughout pregnancy but had a good knowledge of PMTCT of HIV. Only 31.9% of participants knew their HIV status before the booking visit and 33% did not know the HIV status of their partners. Conclusion. The incidence rate of HIV seroconversion in the Fako Division, Cameroon, was 6.8/100 woman-years. No risk factors associated with HIV seroconversion were identified among the study participants because of lack of power to do so. PMID:27127653

  20. Geomagnetism-Paleomagnetism Committee

    NASA Astrophysics Data System (ADS)

    Banerjee, Subir K.

    I n response to strong member concerns about the future of geomagnetism, Neil D. Opdyke, President of the Geomagnetism and Paleomagnetism Section, has appointed an ad hoc Committee for the Future of Geomagnetism and Paleomagnetism consisting of Subir K. Banerjee (chair; University of Minnesota, Minneapolis), Joseph Cain (U.S. Geological Survey, Denver, Colo.) and Rob Van der Voo (University of Michigan, Ann Arbor). The committee seeks, from the membership at large, perceptions of future directions of research, help in identifying a few expanding research areas that show a promise of delivering significant results in the next 5 to 10 years, and guidance in generating a strategy to bring these about.

  1. Report of Ad Hoc Committee on Energy Efficiency in Transportation to the Interdepartmental Fuel and Energy Committee of the State of New York. Interim Report.

    ERIC Educational Resources Information Center

    New York State Interdepartmental Fuel and Energy Committee, Albany.

    After presenting the background of the availability of fuel for transportation and the increasing per capita energy consumption, the report examines the State's role in energy conservation. Five proposals are outlined: (1) a coordinated education program designed to increase public awareness of the current energy situation; (2) a pilot program of…

  2. Report of Ad Hoc Committee on Appliance and Apparatus Efficiency to the Interdepartmental Fuel and Energy Committee of the State of New York. Final Report.

    ERIC Educational Resources Information Center

    New York State Interdepartmental Fuel and Energy Committee, Albany.

    High and wasteful energy consumption practices have become a part of the American life style. The United States, with six percent of the world's population, is responsible for 33 percent of the world's energy consumption. Americans are now faced with shortages of primary fuels, especially natural gas and oil, and with stringency of electric power…

  3. Report of Ad Hoc Committee on Energy Efficiency in Large Buildings to the Interdepartmental Fuel and Energy Committee of the State of New York.

    ERIC Educational Resources Information Center

    New York State Interdepartmental Fuel and Energy Committee, Albany.

    Unwarranted amounts of energy are wasted each year in providing major public and privately owned buildings and the desired environment within them. Improved design, construction, and maintenance and operation can save significant amounts of energy without impairment of these processes throughout the life cycle of these buildings, arbitrarily…

  4. Results of electric vehicle safety issues survey: Conducted on behalf of ad hoc EV battery readiness working group in-vehicle safety sub-working group

    SciTech Connect

    Hunt, G.L.

    1996-06-01

    This report documents the results of a survey conducted in the winter of 1994-1995 by the In-Vehicle Safety Sub-Working Group, a working subunit of the DOE-sponsored ad hoc EV Battery Readiness Working Group. The survey was intended to determine the opinions of a group of industry experts regarding the relative importance of a list of some 39 potential safety concerns, grouped into 8 broad areas related to electric vehicles and their battery systems. Participation in the survey was solicited from the members of the Battery Readiness Working Group, along with members of the SAE EV Battery Safety Issues Task Force and selected other knowledgeable individuals. Results of the survey questionnaire were compiled anonymously from the 38 individuals who submitted responses. For each of the issues, survey respondents ranked them as having high, medium or low importance in each of three areas: the severity of events involving this concern, the probability that such events will occur, and the likelihood that mitigating action for such events may be needed beyond normal practices. The accumulated responses from this ranking activity are tabulated, and the response totals are also provided by several subgroupings of respondents. Additionally, large numbers of written comments were provided by respondents, and these are summarized with numbers of responses indicated. A preliminary statistical analysis of the tabulated results was performed but did not provide a satisfactory ranking of the concerns and has not been included in this report. A list is provided of the 15 concerns which a majority of the respondents indicated could be of both medium-to-high severity and medium-to-high probability of occurrence. This list will be reviewed by the Safety Sub-Working Group to determine the status of actions being taken by industry or government to mitigate these concerns, and the likelihood that additional research, standards development or regulation may be warranted to address them.

  5. Intelligent algorithms for persistent and pervasive sensing in systems comprised of wireless ad hoc networks of ground-based sensors and mobile infrastructures

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2007-04-01

    With the development of low-cost, durable unmanned aerial vehicles (UAVs), it is now practical to perform persistent sensing and target tracking autonomously over broad surveillance areas. These vehicles can sense the environment directly through onboard active sensors, or indirectly when aimed toward ground targets in a mission environment by ground-based passive sensors operating wirelessly as an ad hoc network in the environment. The combination of the swarm intelligence of the airborne infrastructure comprised of UAVs with the ant-like collaborative behavior of the unattended ground sensors creates a system capable of both persistent and pervasive sensing of mission environment, such that, the continuous collection, analysis and tracking of targets from sensor data received from the ground can be achieved. Mobile software agents are used to implement intelligent algorithms for the communications, formation control and sensor data processing in this composite configuration. The enabling mobile agents are organized in a hierarchy for the three stages of processing in the distributed system: target detection, location and recognition from the collaborative data processing among active ground-sensor nodes; transfer of the target information processed on the ground to the UAV swarm overhead; and formation control and sensor activation of the UAV swarm for sustained ground-target surveillance and tracking. Intelligent algorithms are presented that can adapt to the operation of the composite system to target dynamics and system resources. Established routines, appropriate to the processing needs of each stage, are selected as preferred based on their published use in similar scenarios, ability to be distributively implemented over the set of processors at system nodes, and ability to conserve the limited resources at the ground nodes to extend the lifetime of the pervasive network. In this paper, the performance of this distributed, collaborative system concept for

  6. Achieving Congestion Mitigation Using Distributed Power Control for Spectrum Sensor Nodes in Sensor Network-Aided Cognitive Radio Ad Hoc Networks.

    PubMed

    Zhang, Long; Xu, Haitao; Zhuo, Fan; Duan, Hucai

    2017-09-15

    The data sequence of spectrum sensing results injected from dedicated spectrum sensor nodes (SSNs) and the data traffic from upstream secondary users (SUs) lead to unpredictable data loads in a sensor network-aided cognitive radio ad hoc network (SN-CRN). As a result, network congestion may occur at a SU acting as fusion center when the offered data load exceeds its available capacity, which degrades network performance. In this paper, we present an effective approach to mitigate congestion of bottlenecked SUs via a proposed distributed power control framework for SSNs over a rectangular grid based SN-CRN, aiming to balance resource load and avoid excessive congestion. To achieve this goal, a distributed power control framework for SSNs from interior tier (IT) and middle tier (MT) is proposed to achieve the tradeoff between channel capacity and energy consumption. In particular, we firstly devise two pricing factors by considering stability of local spectrum sensing and spectrum sensing quality for SSNs. By the aid of pricing factors, the utility function of this power control problem is formulated by jointly taking into account the revenue of power reduction and the cost of energy consumption for IT or MT SSN. By bearing in mind the utility function maximization and linear differential equation constraint of energy consumption, we further formulate the power control problem as a differential game model under a cooperation or noncooperation scenario, and rigorously obtain the optimal solutions to this game model by employing dynamic programming. Then the congestion mitigation for bottlenecked SUs is derived by alleviating the buffer load over their internal buffers. Simulation results are presented to show the effectiveness of the proposed approach under the rectangular grid based SN-CRN scenario.

  7. Analysis of location-aware QoS-routing protocols based on partial temporal and spatial topology for real-time multimedia in mobile ad hoc networks

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2004-08-01

    In the distributed operations of route discovery and maintenance, strong interaction occurs across mobile ad hoc network (MANET) protocol layers in the transport of service packets between source and destination nodes. Quality of service (QoS) requirements are specified for multimedia service classes by the application layer. Due to node mobility, knowledge of their locations is inherently incomplete. Network topology is thus only partially known in time and in space. Cross-layer interactions in the protocol are modeled in terms of a set of concatenated design parameters, updates on node positions and associated energy costs. Functional dependencies of the QoS metrics on the concatenated parameters are described. An analytical framework is established for development of new cross-layer designs that optimize layer interdependencies to achieve the "best" QoS available in the MANET given a partially known, time-varying topology. The designs, based on a reactive MANET protocol, adapt provisioned QoS to dynamic network conditions and residual energy capacities. Cross-layer optimization, given partially known topology, is based on stochastic dynamic programming and predictive estimation conditions derived from time-dependent models of MANET behavior. Models of real-time behavior are based on the control of conditional rates of multivariate point processes (MVPPs). These rates depend on the concatenated protocol and resource parameters. The analytical framework supports predictive models to estimate node mobility in addition to measurement-based estimates of probability distributions for voice, video, data, and other Internet traffic. Estimates of QoS metrics are given in terms of recursive stochastic filters of the network state, based on complete or partial observations of topology and events.

  8. Achieving Congestion Mitigation Using Distributed Power Control for Spectrum Sensor Nodes in Sensor Network-Aided Cognitive Radio Ad Hoc Networks

    PubMed Central

    Zhuo, Fan; Duan, Hucai

    2017-01-01

    The data sequence of spectrum sensing results injected from dedicated spectrum sensor nodes (SSNs) and the data traffic from upstream secondary users (SUs) lead to unpredictable data loads in a sensor network-aided cognitive radio ad hoc network (SN-CRN). As a result, network congestion may occur at a SU acting as fusion center when the offered data load exceeds its available capacity, which degrades network performance. In this paper, we present an effective approach to mitigate congestion of bottlenecked SUs via a proposed distributed power control framework for SSNs over a rectangular grid based SN-CRN, aiming to balance resource load and avoid excessive congestion. To achieve this goal, a distributed power control framework for SSNs from interior tier (IT) and middle tier (MT) is proposed to achieve the tradeoff between channel capacity and energy consumption. In particular, we firstly devise two pricing factors by considering stability of local spectrum sensing and spectrum sensing quality for SSNs. By the aid of pricing factors, the utility function of this power control problem is formulated by jointly taking into account the revenue of power reduction and the cost of energy consumption for IT or MT SSN. By bearing in mind the utility function maximization and linear differential equation constraint of energy consumption, we further formulate the power control problem as a differential game model under a cooperation or noncooperation scenario, and rigorously obtain the optimal solutions to this game model by employing dynamic programming. Then the congestion mitigation for bottlenecked SUs is derived by alleviating the buffer load over their internal buffers. Simulation results are presented to show the effectiveness of the proposed approach under the rectangular grid based SN-CRN scenario. PMID:28914803

  9. The Defense Committees of Sleepy Lagoon: A Convergent Struggle against Fascism, 1942-1944

    ERIC Educational Resources Information Center

    Barajas, Frank P.

    2006-01-01

    The Sleepy Lagoon Defense Committee originated as an ad hoc committee and evolved to a broad-based movement for legal justice on behalf of seventeen youth convicted of murder and assault charges in connection with the Sleepy Lagoon case in Los Angeles in January 1943. This essay chronicles the multidimensional organizing to shift public opinion in…

  10. The Defense Committees of Sleepy Lagoon: A Convergent Struggle against Fascism, 1942-1944

    ERIC Educational Resources Information Center

    Barajas, Frank P.

    2006-01-01

    The Sleepy Lagoon Defense Committee originated as an ad hoc committee and evolved to a broad-based movement for legal justice on behalf of seventeen youth convicted of murder and assault charges in connection with the Sleepy Lagoon case in Los Angeles in January 1943. This essay chronicles the multidimensional organizing to shift public opinion in…

  11. Bioconversion of α-linolenic acid into n-3 long-chain polyunsaturated fatty acid in hepatocytes and ad hoc cell culture optimisation.

    PubMed

    Alhazzaa, Ramez; Sinclair, Andrew J; Turchini, Giovanni M

    2013-01-01

    This study aimed to establish optimal conditions for a cell culture system that would allow the measurement of 18:3n-3 (ALA) bioconversion into n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA), and to determine the overall pathway kinetics. Using rat hepatocytes (FaO) as model cells, it was established that a maximum 20:5n-3 (EPA) production from 50 µM ALA initial concentration was achieved after 3 days of incubation. Next, it was established that a gradual increase in the ALA concentration from 0 up to 125 µM lead to a proportional increase in EPA, without concomitant increase in further elongated or desaturated products, such as 22:5n-3 (DPA) and 22:6n-3 (DHA) in 3 day incubations. Of interest, ALA bioconversion products were observed in the culture medium. Therefore, in vitro experiments disregarding the medium fatty acid content are underestimating the metabolism efficiency. The novel application of the fatty acid mass balance (FAMB) method on cell culture system (cells with medium) enabled quantifying the apparent enzymatic activities for the biosynthesis of n-3 LC-PUFA. The activity of the key enzymes was estimated and showed that, under these conditions, 50% (Km) of the theoretical maximal (V max = 3654 µmol.g(-1) of cell protein.hour(-1)) Fads2 activity on ALA can be achieved with 81 µM initial ALA. Interestingly, the apparent activity of Elovl2 (20:5n-3 elongation) was the slowest amongst other biosynthesis steps. Therefore, the possible improvement of Elovl2 activity is suggested toward a more efficient DHA production from ALA. The present study proposed and described an ad hoc optimised cell culture conditions and methodology towards achieving a reliable experimental platform, using FAMB, to assist in studying the efficiency of ALA bioconversion into n-3 LC-PUFA in vitro. The FAMB proved to be a powerful and inexpensive method to generate a detailed description of the kinetics of n-3 LC-PUFA biosynthesis enzymes activities in vitro.

  12. Bioconversion of α-Linolenic Acid into n-3 Long-Chain Polyunsaturated Fatty Acid in Hepatocytes and Ad Hoc Cell Culture Optimisation

    PubMed Central

    Alhazzaa, Ramez; Sinclair, Andrew J.; Turchini, Giovanni M.

    2013-01-01

    This study aimed to establish optimal conditions for a cell culture system that would allow the measurement of 18∶3n-3 (ALA) bioconversion into n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA), and to determine the overall pathway kinetics. Using rat hepatocytes (FaO) as model cells, it was established that a maximum 20∶5n-3 (EPA) production from 50 µM ALA initial concentration was achieved after 3 days of incubation. Next, it was established that a gradual increase in the ALA concentration from 0 up to 125µM lead to a proportional increase in EPA, without concomitant increase in further elongated or desaturated products, such as 22∶5n-3 (DPA) and 22∶6n-3 (DHA) in 3 day incubations. Of interest, ALA bioconversion products were observed in the culture medium. Therefore, in vitro experiments disregarding the medium fatty acid content are underestimating the metabolism efficiency. The novel application of the fatty acid mass balance (FAMB) method on cell culture system (cells with medium) enabled quantifying the apparent enzymatic activities for the biosynthesis of n-3 LC-PUFA. The activity of the key enzymes was estimated and showed that, under these conditions, 50% (Km) of the theoretical maximal (Vmax = 3654 µmol.g−1 of cell protein.hour−1) Fads2 activity on ALA can be achieved with 81 µM initial ALA. Interestingly, the apparent activity of Elovl2 (20∶5n-3 elongation) was the slowest amongst other biosynthesis steps. Therefore, the possible improvement of Elovl2 activity is suggested toward a more efficient DHA production from ALA. The present study proposed and described an ad hoc optimised cell culture conditions and methodology towards achieving a reliable experimental platform, using FAMB, to assist in studying the efficiency of ALA bioconversion into n-3 LC-PUFA in vitro. The FAMB proved to be a powerful and inexpensive method to generate a detailed description of the kinetics of n-3 LC-PUFA biosynthesis enzymes activities in vitro

  13. Incorporating the patient's perspective into drug development and communication: an ad hoc task force report of the Patient-Reported Outcomes (PRO) Harmonization Group meeting at the Food and Drug Administration, February 16, 2001.

    PubMed

    Acquadro, Catherine; Berzon, Rick; Dubois, Dominique; Leidy, Nancy Kline; Marquis, Patrick; Revicki, Dennis; Rothman, Margaret

    2003-01-01

    The extent to which patient-based outcomes can be used to evaluate and communicate the effect of new drugs and devices is a subject of much debate. Criteria for evaluating the scientific quality of data to support health-related quality of life (HRQL) and other patient-based labeling and promotional claims in the United States and Europe have been proposed by various scientists and organizations. Since March 2000, a working group composed of members of the International Society for Quality of Life Research (ISOQOL), the International Society for Pharmacoeconomics and Outcomes Research (ISPOR), the Pharmaceutical Manufacturer's Association Health Outcomes Committee (PhRMA-HOC), and the European Regulatory Issues on Quality of Life Assessment (ERIQA) met to discuss and coordinate the various recommendations by their respective groups and address the need to harmonize outcomes review criteria within and across United States and European regulatory agencies. Over time, the discussion expanded from HRQL outcomes to include any outcome based on data provided by the patient or patient proxy, that is, patient-reported outcomes (PROs). The working group therefore became known as the PRO Harmonization Group. Working with a member of the US Food and Drug Administration (FDA), four key issues requiring clarification were identified: how PROs are defined and put into operation for research purposes; the added value of PROs in the drug review and evaluation process; selected questions related to the PRO measurement and research methodology; and the interest and demand for PRO information by decision makers. On February 15, 2001, all members of the PRO Harmonization Group attended a meeting in Rockville, Maryland, to discuss these four issues further, and on February 16, 2001, a formal presentation was made to representatives from various departments and reviewing divisions of the FDA. These presentations are summarized in this report. All participants agreed that PROs are

  14. Monitoring of slope-instabilities and deformations with Micro-Electro-Mechanical-Systems (MEMS) in wireless ad-hoc Sensor Networks

    NASA Astrophysics Data System (ADS)

    Arnhardt, C.; Fernández-Steeger, T. M.; Azzam, R.

    2009-04-01

    In most mountainous regions, landslides represent a major threat to human life, properties and infrastructures. Nowadays existing landslide monitoring systems are often characterized by high efforts in terms of purchase, installation, maintenance, manpower and material. In addition (or because of this) only small areas or selective points of the endangered zone can be observed by the system. Therefore the improvement of existing and the development of new monitoring and warning systems are of high relevance. The joint project "Sensor based Landslide Early Warning Systems" (SLEWS) deals with the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using low-cost micro-sensors (MEMS) integrated in a wireless sensor network (WSN). Modern so called Ad-Hoc, Multi-Hop wireless sensor networks (WSN) are characterized by a self organizing and self-healing capacity of the system (autonomous systems). The network consists of numerous individual and own energy-supply operating sensor nodes, that can send data packages from their measuring devices (here: MEMS) over other nodes (Multi-Hop) to a collection point (gateway). The gateway provides the interface to central processing and data retrieval units (PC, Laptop or server) outside the network. In order to detect and monitor the different landslide processes (like fall, topple, spreading or sliding) 3D MEMS capacitive sensors made from single silicon crystals and glass were chosen to measure acceleration, tilting and altitude changes. Based on the so called MEMS (Micro-Electro-Mechanical Systems) technology, the sensors combine very small mechanical and electronic units, sensing elements and transducers on a small microchip. The mass production of such type of sensors allows low cost applications in different areas (like automobile industries, medicine, and automation technology). Apart from the small and so space saving size and the low costs another advantage is the energy

  15. Committees

    NASA Astrophysics Data System (ADS)

    Williams, Gwyn P.; Revesz, Peter; Arp, Uwe

    2014-03-01

    Conference Chairs NameOrganization Gwyn Williams Jefferson Lab Peter ReveszCornell High Energy Synchrotron Source Uwe ArpSynchrotron Ultraviolet Radiation Facility Programme Committee NameOrganization Alastair MacDowellAdvanced Light Source Tom ToellnerAdvanced Photon Source Amitava D RoyCenter for Advanced Microstructures and Devices Tom EllisCanadian Light Source Roberta SantarosaLaboratório Nacional de Luz Síncrotron Jerry (Jerome) HastingsLinac Coherent Light Source Steven HulbertNational Synchrotron Light Source Thomas A RabedeauStanford Synchrotron Radiation Lightsource Mark BissenSynchrotron Radiation Center Gwyn WilliamsJefferson Lab Peter ReveszCornell High Energy Synchrotron Source Uwe ArpSynchrotron Ultraviolet Radiation Facility

  16. Committees

    NASA Astrophysics Data System (ADS)

    2012-11-01

    Leadership Team of the IAHR Committee for Hydraulic Machinery and Systems Eduard EGUSQUIZA, UPC Barcelona, Spain, Chair François AVELLAN, EPFL-LMH, Switzerland, Past Chair Richard K FISHER, Voith Hydro Inc., USA, Past Chair Fidel ARZOLA, Edelca, Venezuela Michel COUSTON, Alstom Hydro, France Niklas DAHLBÄCKCK, Vatenfall, Sweden Normand DESY, Andritz VA TECH Hydro Ltd., Canada Chisachi KATO, University of Tokyo, Japan Andrei LIPEJ, Turboinstitut, Slovenija Torbjørn NIELSEN, NTNU, Norway Romeo SUSAN-RESIGA, 'Politehnica' University Timisoara, Romania Stefan RIEDELBAUCH, Stuggart University, Germany Albert RUPRECHT, Stuttgart University, Germany Qing-Hua SHI, Dong Fang Electrical Machinery Co., China Geraldo TIAGO, Universidade Federal de Itajubá, Brazil International Advisory Committee Shouqi YUAN (principal) Jiangsu University China QingHua SHI (principal) Dong Fang Electrical Machinery Co. China Fidel ARZOLA EDELCA Venezuela Thomas ASCHENBRENNER Voith Hydro GmbH & Co. KG Germany Anton BERGANT Litostroj Power doo Slovenia B C BHAOYAL Research & Technology Centre India Hermod BREKKE NTNU Norway Stuart COULSON Voith Hydro Inc. USA Paul COOPER Fluid Machinery Research Inc USA V A DEMIANOV Power Machines OJSC Russia Bart van ESCH Technische Universiteit Eindhoven Netherland Arno GEHRER Andritz Hydro Graz Austria Akira GOTO Ebara Corporation Japan Adiel GUINZBURG The Boeing Company USA D-H HELLMANN KSB AG Germany Ashvin HOSANGADI Combustion Research and Flow Technology USA Byung-Sun HWANG Korea Institute of Material Science Korea Toshiaki KANEMOTO Kyushu Institute of Technology Japan Mann-Eung KIM Korean Register of Shipping Korea Jiri KOUTNIK Voith Hydro GmbH & Co. KG Germany Jinkook LEE Eaton Corporation USA Young-Ho LEE Korea Maritime University Korea Woo-Seop LIM Hyosung Goodsprings Inc Korea Jun MATSUI Yokohama National University Japan Kazuyoshi Mitsubishi H I Ltd, Japan MIYAGAWA Christophe NICOLET Power Vision Engineering Srl Switzerland Maryse PAGE Hydro

  17. Should the University of Wisconsin-Eau Claire Seek NCATE Reaccreditation in 1983? Report of the Ad Hoc NCATE Study Committee.

    ERIC Educational Resources Information Center

    Whooley, John; And Others

    A study by the School of Education at the University of Wisconsin at Eau Claire (UWEC) was designed to provide information on whether UWEC should seek NCATE (National Council of Accreditation for Teacher Education) reaccreditation for its graduate and undergraduate teacher education programs in 1983. The essential question in the study was whether…

  18. A Design for Living: The PARC Plan. Report of the PARC Ad Hoc Planning Committee for Resolution II, October 19, 1974.

    ERIC Educational Resources Information Center

    Pennsylvania Association for Retarded Citizens, Harrisburg.

    Presented is the PARC (Pennsylvania Association for Retarded Citizens) Plan which resulted from a 3-month survey of Pennsylvania's institutional system and which was designed to improve living conditions and programs of state schools and hospitals serving the mentally retarded. Detailed are specific recommendations for the achievement of annual…

  19. Education in the Balance: A Report on the Academic Workforce in English. Report of the 2007 ADE Ad Hoc Committee on Staffing

    ERIC Educational Resources Information Center

    Modern Language Association, 2008

    2008-01-01

    The National Study of Postsecondary Faculty (NSOPF) surveys more than 26,000 faculty members in all fields in US colleges and universities. Those canvassed by the NSOPF form a nationally representative sample of full- and part-time faculty members in degree-granting public and private not-for-profit institutions that are located in the 50 states…

  20. Guidelines for the detection of high-risk lipoprotein profiles and the treatment of dyslipoproteinemias. Canadian Lipoprotein Conference Ad Hoc Committee on Guidelines for Dyslipoproteinemias.

    PubMed Central

    1990-01-01

    Elevated plasma levels of cholesterol and triglycerides, low levels of high-density lipoproteins, hypertension, diabetes mellitus, smoking and abdominal obesity are risk factors for coronary heart disease (CHD) and stroke. Because of the preventable threat to life, well-being and productivity from perturbations of plasma lipoproteins (which affect about 60% of adults), we recommend a population-based strategy with public education on diet, exercise and the hazards of smoking and legislation for better food labelling. This should be combined with the medical guidelines we describe to detect and treat those at highest risk for CHD (including about 15% of adults), who merit priority for the medical, dietetic and laboratory services required. Among people aged 40 years or more this includes those with plasma total cholesterol levels greater than 7 mmol/L, fasting triglyceride levels greater than 3 mmol/L or cholesterol level greater than 6 mmol/L when associated with CHD or other risk factors for CHD. For younger people the criteria for highest risk include cholesterol levels greater than 6.5 mmol/L for those aged 30 to 39 years, greater than 6 mmol/L for those aged 20 to 29 and greater than 5 mmol/L for those under age 20. PMID:2190685

  1. [Multimodal pain therapy for treatment of chronic pain syndrome. Consensus paper of the ad hoc commission on multimodal interdisciplinary pain management of the German Pain Society on treatment contents].

    PubMed

    Arnold, B; Brinkschmidt, T; Casser, H-R; Diezemann, A; Gralow, I; Irnich, D; Kaiser, U; Klasen, B; Klimczyk, K; Lutz, J; Nagel, B; Pfingsten, M; Sabatowski, R; Schesser, R; Schiltenwolf, M; Seeger, D; Söllner, W

    2014-10-01

    Multimodal pain management is a comprehensive treatment of complex chronic pain syndromes. In addition to medical therapy various other specialized therapeutic interventions based on the biopsychosocial model of pain origin and chronic pain development, are added. During the last few years treatment centers for chronic pain have been established throughout Germany. Multimodal pain management has been included in the official catalogue of the recognized medical procedures for day clinic units as well as for inpatient pain management. In daily practice there is, however, still a lack of clarity and of consistency about the components that multimodal pain management should contain. This is the reason for the ad hoc commission on multimodal interdisciplinary pain management of the German Pain Society to propose the following position paper that has been worked out in a multilevel and interdisciplinary consensus process. The paper describes the mandatory treatment measures in the four core disciplines of multimodal pain management, pain medicine, psychotherapy, exercise therapy including physiotherapy and assistant medical professions including nurses.

  2. Report of the ad-hoc consultation on aging and immunization for a future WHO research agenda on life-course immunization.

    PubMed

    Thomas-Crusells, Judith; McElhaney, Janet E; Aguado, M Teresa

    2012-09-14

    WHO convened a meeting of around 30 experts to address the topic of aging and immunization in March 2011 in Geneva. The purpose of the meeting was to develop a global research agenda to eventually inform WHO policy recommendations regarding immunization beyond childhood and into old age. This issue is becoming more critical, since the population aged 60 and above will reach two billion people - three-quarters of whom will be in developing countries - in the next 40 years. The meeting reviewed current knowledge and gaps in information about: (1) the epidemiology of infectious diseases in the elderly in developed and developing countries and their contribution to disability in old age; (2) the deterioration of the immune system with age ("immune senescence") and possible ways to measure and counteract it; and (3) immunization approaches to maintain or improve health in older persons. These approaches include the concept of a "life-course vaccination" schedule to help sustain immunity to vaccine-preventable diseases beyond childhood and into old age; strategies to strengthen older persons' responses to vaccines (e.g., by adding adjuvants to vaccines, increasing vaccine dosage, and intradermal vaccine administration); and the possible development of new vaccines targeted specifically for older adults. Participants proposed priority research topics as well as strategies to facilitate and coordinate the research, including the establishment of networks of collaborators, with WHO playing a key coordinating role.

  3. Lentiviral haemopoietic stem-cell gene therapy in early-onset metachromatic leukodystrophy: an ad-hoc analysis of a non-randomised, open-label, phase 1/2 trial.

    PubMed

    Sessa, Maria; Lorioli, Laura; Fumagalli, Francesca; Acquati, Serena; Redaelli, Daniela; Baldoli, Cristina; Canale, Sabrina; Lopez, Ignazio D; Morena, Francesco; Calabria, Andrea; Fiori, Rossana; Silvani, Paolo; Rancoita, Paola M V; Gabaldo, Michela; Benedicenti, Fabrizio; Antonioli, Gigliola; Assanelli, Andrea; Cicalese, Maria Pia; Del Carro, Ubaldo; Sora, Maria Grazia Natali; Martino, Sabata; Quattrini, Angelo; Montini, Eugenio; Di Serio, Clelia; Ciceri, Fabio; Roncarolo, Maria Grazia; Aiuti, Alessandro; Naldini, Luigi; Biffi, Alessandra

    2016-07-30

    Metachromatic leukodystrophy (a deficiency of arylsulfatase A [ARSA]) is a fatal demyelinating lysosomal disease with no approved treatment. We aimed to assess the long-term outcomes in a cohort of patients with early-onset metachromatic leukodystrophy who underwent haemopoietic stem-cell gene therapy (HSC-GT). This is an ad-hoc analysis of data from an ongoing, non-randomised, open-label, single-arm phase 1/2 trial, in which we enrolled patients with a molecular and biochemical diagnosis of metachromatic leukodystrophy (presymptomatic late-infantile or early-juvenile disease or early-symptomatic early-juvenile disease) at the Paediatric Clinical Research Unit, Ospedale San Raffaele, in Milan. Trial participants received HSC-GT, which consisted of the infusion of autologous HSCs transduced with a lentiviral vector encoding ARSA cDNA, after exposure-targeted busulfan conditioning. The primary endpoints of the trial are safety (toxicity, absence of engraftment failure or delayed haematological reconstitution, and safety of lentiviral vector-tranduced cell infusion) and efficacy (improvement in Gross Motor Function Measure [GMFM] score relative to untreated historical controls, and ARSA activity, 24 months post-treatment) of HSC-GT. For this ad-hoc analysis, we assessed safety and efficacy outcomes in all patients who had received treatment and been followed up for at least 18 months post-treatment on June 1, 2015. This trial is registered with ClinicalTrials.gov, number NCT01560182. Between April, 2010, and February, 2013, we had enrolled nine children with a diagnosis of early-onset disease (six had late-infantile disease, two had early-juvenile disease, and one had early-onset disease that could not be definitively classified). At the time of analysis all children had survived, with a median follow-up of 36 months (range 18-54). The most commonly reported adverse events were cytopenia (reported in all patients) and mucositis of different grades of severity (in five

  4. Hearings Before the Select Committee on Nutrition and Human Needs of the United States Senate, Ninety-Second Congress, First Session on Nutrition and Human Needs. Part 4--Implementation, 1970 Amendments to the National School Lunch Act. Hearings Held Washington, D.C., May 3-4, 1971.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Select Committee on Nutrition and Human Needs.

    In trying to solve the problem of hunger in the classroom, the Senate Select Committee on Nutrition and Human Needs heard the testimony of many witnesses, among whom were: Miss Barbara Bode, Program Director, The Children's Foundation; Miss Barbara Hockert, President, Burlington Ad Hoc Committee on School Lunches; and, Mrs. Joseph H. Young,…

  5. Hearings Before the Select Committee on Nutrition and Human Needs of the United States Senate, Ninety-Second Congress, First Session on Nutrition and Human Needs. Part 4--Implementation, 1970 Amendments to the National School Lunch Act. Hearings Held Washington, D.C., May 3-4, 1971.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Select Committee on Nutrition and Human Needs.

    In trying to solve the problem of hunger in the classroom, the Senate Select Committee on Nutrition and Human Needs heard the testimony of many witnesses, among whom were: Miss Barbara Bode, Program Director, The Children's Foundation; Miss Barbara Hockert, President, Burlington Ad Hoc Committee on School Lunches; and, Mrs. Joseph H. Young,…

  6. [From Nuremberg to the ethics committees in human experimentation].

    PubMed

    Demarez, Jean-Paul

    2008-02-01

    During the Nuremberg trials, the accusation prompted the creation of an ad hoc committee to advise on human experiments carried out on prisoners during wartime in the USA. Precisely a charge that had been brought against Karl Brandt and his colleagues. This committee was the forerunner of the Independent Committees, to which the Declaration of Helsinki assigned a role in analysing the ethics of research projects in humans. From 1980 onwards, in industrialised countries, the legislation regarding clinical trials began to incorporate similar structures, IRBs in the United States of America, Ethics Committees elsewhere, and the ''Committee for the Protection of Persons" in France. However, at that time, in spite of the misleading words, we went from ethics to law, from rules of conduct intended for researchers to legal regulations organising relations between sponsors, investigators and persons participating in biomedical research, which is not the same thing.

  7. Life Cycles of Ad Hoc Task Groups

    DTIC Science & Technology

    1983-10-01

    internal group dynamics, and external influence on the group . Time pressure . Members’ first comments about time pressure appeared at transition meetings...organizational supports and management behavior can influence team effectiveness. Yet it is unclear how such factors may affect the group "_.3...on members’ ability to work together, yet little is known about how the gradual creation of work products influences groups ’ social development. The

  8. Distribution of Information in Ad Hoc Networks

    DTIC Science & Technology

    2007-09-01

    requiring coverage. It means that when the density of the network is important precision approaches 1 (perfect case). 0l 1l 2l 3l 4l .3 100 ...information decreases, and vice versa. For the case where the number of nodes is 100 in the 800m*800m zone, the density is light; the distribution of those...information source nodes in a graph of infinite density . Thus, nodes can be laid out where desired. Second, it provides an algorithm which achieves an

  9. Swift Trust in Distributed Ad Hoc Teams

    DTIC Science & Technology

    2007-10-04

    team at risk. Questionnaires assessed the impact of regimental identity and potential trust violations on levels of team trust before the mission...personnellement. Cette notion est de plus en plus utilisée dans les ouvrages spécialisés pour expliquer comment les membres des équipes spéciales... questionnaires distribués aux participants ont permis d’évaluer l’impact de l’identité régimentaire et des abus de confiance sur le niveau de confiance

  10. Ad hoc attribute-value prediction

    SciTech Connect

    Melli, G.

    1996-12-31

    The evolving ease and efficiency in accessing large amounts of data presents an opportunity to execute prediction tasks based on this data. Research in learning-from-example has addressed this opportunity with algorithms that induce either decision structures (ID3) or classification rules (AQ15). Lazy learning research on the other hand, delay the model construction to strictly satisfy a prediction task. To support a prediction query against a data set, current techniques require a large amount of preprocessing to either construct a complete domain model, or to determine attribute relevance. Our work in this area is to develop an algorithm that will automatically return a probabilistic classification rule for a prediction query with equal accuracy to current techniques but with no preprocessing requirements. The proposed algorithm, DBPredictor, combines the delayed model construction approach of lazy learning along with the information theoretic measure and top-down heuristic search of learning-from-example algorithms. The algorithm induces only the information required to satisfy the prediction query and avoids the attribute relevance tests required by the nearest-neighbor measures of lazy learning.

  11. Mobile Ad Hoc Network Emulation Environment

    DTIC Science & Technology

    2009-10-01

    and debugging information in both real-time and post-test-run playback modes. Display characteristics are controlled by the test nodes, which pass...2007. MILCOM 2007. IEEE , vol., no., pp.I-6, 29-31 Oct. 2007. [IS] http ://cs.itd.nrl.navy.mil /work/rapr/index, php [16] http ://www.alionscience.com

  12. Ad-Hoc Implicature in Preschool Children

    ERIC Educational Resources Information Center

    Stiller, Alex J.; Goodman, Noah D.; Frank, Michael C.

    2015-01-01

    If a speaker tells us that "some guests were late to the party," we typically infer that not all were. Implicatures, in which an ambiguous statement ("some and possibly all") is strengthened pragmatically (to "some and not all"), are a paradigm case of pragmatic reasoning. Inferences of this sort are difficult for…

  13. Ad-Hoc Implicature in Preschool Children

    ERIC Educational Resources Information Center

    Stiller, Alex J.; Goodman, Noah D.; Frank, Michael C.

    2015-01-01

    If a speaker tells us that "some guests were late to the party," we typically infer that not all were. Implicatures, in which an ambiguous statement ("some and possibly all") is strengthened pragmatically (to "some and not all"), are a paradigm case of pragmatic reasoning. Inferences of this sort are difficult for…

  14. SPE-electronic publishing committee: 1995 update on initiatives

    SciTech Connect

    Thrasher, T.S.; Kemp, B.D.

    1995-12-31

    The primary mission of the Society of Petroleum Engineers (SPE) is to disseminate petroleum engineering technology. One of the most important sources of petroleum engineering technology is the extensive inventory (over 25,000) of SPE technical papers. In October 1991 the SPE Board authorized the Ad Hoc Electronic Publishing Committee (EPC) to explore how electronic publishing technologies might help the SPE promote the dissemination of petroleum engineering technology. The purpose of this paper is to update members on the progress of the SPE Electronic Publishing Committee, current projects and initiatives, vision for the future, and to encourage member support.

  15. COMMITTEES COMMITTEES

    NASA Astrophysics Data System (ADS)

    2010-11-01

    ORGANISING COMMITTEE Chairman: Alexander G Petrov Director, Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria Chairman Emeritus: Nikolay Kirov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria Local Organising Committee: Chairman: Alexander G Petrov Members: Diana Nesheva, Doriana Dimova-Malinovska, Eleonora Popova, Lyubomila Dedinska, Christo Popov, Vasil Lovchinov, Marina Primatarowa, Emilia Vlaikova, Irina Velkova, Hassan Chamati PROGRAMME COMMITTEE Chairman: A G Petrov Members: D Alexandrov (Thunder Bay), V Celebonovic (Belgrade), D Dimova-Malinovska (Sofia), B Dulmet (Besancon), A Grechnikov (Moscow), M Gunes (Mugla), C Main (Dundee), D Nesheva (Sofia), M C Petty (Durham), M Popescu (Bucharest), S Reynolds (Dundee), K Shimakawa (Gifu), J Singh (Darwin), N Starbov (Sofia), M Tomilin (St Petersburg), Ph Vanderbemden (Liege), A Vaseashta (Washington) LOCAL SCIENTIFIC COUNCIL Chairman: A G Petrov Members: Bulgarian Academy of Sciences N Sabotinov (President) I Nedkov (Scientific Secretary, Physics) Institute of Solid State Physics N Kirov, D Nesheva, V Lovchinov, St Andreev, M Primatarowa Institute of Electronics R Enikov (Director) Central Lab. of Solar Energy and New Energy Sources D Dimova-Malinovska Institute of Optical Materials and Technologies V Saynov, N Starbov Central Lab. of Applied Physics R Kakanakov (Director) Sofia University - Faculty of Physics A Andreeva, S Russev (Heads of Departments)

  16. COMMITTEES: Committees

    NASA Astrophysics Data System (ADS)

    2010-01-01

    TAUP STEERING COMMITTEE F T Avignone, University of South Carolina B C Barish, CALTECH E Bellotti, University of Milano, INFN J Bernabeu, University of Valencia A Bottino (Chair), University of Torino, INFN N Fornengo, University of Torino, INFN T Kajita, ICRR University of Tokyo C W Kim, Johns Hopkins University, KIAS V Matveev, INR Moscow J Morales, University of Zaragoza G Raffelt, MPI Munchen D Sinclair, University of Carleton M Spiro, IN2P3 TAUP 2009 INTERNATIONAL ADVISORY COMMITTEE J J Aubert, CNRS Marseille M Baldo-Ceolin, University of Padova, INFN G Bellini, University of Milano, INFN L Bergstrom, University of Stockholm R Bernabei, University of Roma Tor Vergata, INFN A Bettini, University of Padova, INFN, LSC S Bilenky, JINR Dubna D O Caldwell, UCSB J Cronin, University of Chicago A Dar, Technion Haifa G Domogatsky, INR Moscow J Ellis, CERN E Fernandez, IFAE Barcelona E Fiorini, University of Milano, INFN T Gaisser, University of Delaware G Gelmini, UCLA G Gerbier, CEA Saclay A Giazotto, INFN Pisa F Halzen, University of Wisconsin W Haxton, University of Washington T Kirsten MPI Heidelberg L Maiani, University of Roma La Sapienza, INFN A McDonald, Queen's University K Nakamura, KEK R Petronzio, INFN, University of Roma Tor Vergata L Resvanis, University of Athens F Ronga INFN, LNF C Rubbia INFN, LNGS A Smirnov, ICTP Trieste C Spiering, DESY N Spooner, University of Sheffield A Suzuki, KEK S Ting MIT, CERN M S Turner, FNAL, University of Chicago J W F Valle, IFIC Valencia D Vignaud, APC Paris G Zatsepin, INR Moscow TAUP 2009 ORGANIZING COMMITTEE R Aloisio, LNGS R Antolini, LNGS F Arneodo, LNGS Z Berezhiani, University of L'Aquila, INFN V Berezinsky, LNGS R Cerulli, LNGS E Coccia [Chair], LNGS/INFN, U of Roma Tor Vergata N D'Ambrosio, LNGS N Fornengo, University of Torino, INFN M Laubenstein, LNGS O Palamara, LNGS L Pandola [Scientific Secretary], LNGS

  17. Primary Immunodeficiency Diseases: An Update on the Classification from the International Union of Immunological Societies Expert Committee for Primary Immunodeficiency

    PubMed Central

    Al-Herz, Waleed; Bousfiha, Aziz; Casanova, Jean-Laurent; Chapel, Helen; Conley, Mary Ellen; Cunningham-Rundles, Charlotte; Etzioni, Amos; Fischer, Alain; Franco, Jose Luis; Geha, Raif S.; Hammarström, Lennart; Nonoyama, Shigeaki; Notarangelo, Luigi Daniele; Ochs, Hans Dieter; Puck, Jennifer M.; Roifman, Chaim M.; Seger, Reinhard; Tang, Mimi L. K.

    2011-01-01

    We report the updated classification of primary immunodeficiency diseases, compiled by the ad hoc Expert Committee of the International Union of Immunological Societies. As compared to the previous edition, more than 15 novel disease entities have been added in the updated version. For each disorders, the key clinical and laboratory features are provided. This updated classification is meant to help in the diagnostic approach to patients with these diseases. PMID:22566844

  18. 78 FR 49737 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ... and Remediation Committee, Waste Management Committee, and Waste Isolation Pilot Plant Ad Hoc... of the Waste Isolation Pilot Plant (WIPP) Ad Hoc Committee: The WIPP Ad Hoc Committee is preparing a...

  19. 78 FR 58293 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... and Remediation Committee, Waste Management Committee, and Waste Isolation Pilot Plant Ad Hoc... of the Waste Isolation Pilot Plant (WIPP) Ad Hoc Committee: The WIPP Ad Hoc Committee is preparing a...

  20. 78 FR 44941 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-25

    ... and Remediation Committee, Waste Management Committee, and Waste Isolation Pilot Plant Ad Hoc... of the Waste Isolation Pilot Plant (WIPP) Ad Hoc Committee: The WIPP Ad Hoc Committee is preparing a...

  1. On Post-Hoc Blocking.

    ERIC Educational Resources Information Center

    Bonett, Douglas G.

    1982-01-01

    Post-hoc blocking and analysis of covariance (ANCOVA) both employ a concomitant variable to increase statistical power relative to the completely randomized design. It is argued that the advantages attributed to the block design are not always valid and that there are circumstances when the ANCOVA would be preferred to post-hoc blocking.…

  2. Cross-cultural adaptation of the Health Education Impact Questionnaire: experimental study showed expert committee, not back-translation, added value.

    PubMed

    Epstein, Jonathan; Osborne, Richard H; Elsworth, Gerald R; Beaton, Dorcas E; Guillemin, Francis

    2015-04-01

    To assess the contribution of back-translation and expert committee to the content and psychometric properties of a translated multidimensional questionnaire. Recommendations for questionnaire translation include back-translation and expert committee, but their contribution to measurement properties is unknown. Four English to French translations of the Health Education Impact Questionnaire were generated with and without committee or back-translation. Face validity, acceptability, and structural properties were compared after random assignment to people with rheumatoid arthritis (N = 1,168), chronic renal failure (N = 2,368), and diabetes (N = 538). For face validity, 15 bilingual people compared translations quality with the original. Psychometric properties were examined using confirmatory factor analysis (metric and scalar invariance) and item response theory. Qualitatively, there were five types of translation errors: style, intensity, frequency/time frame, breadth, and meaning. Bilingual assessors ranked best the translations with committee (P = 0.0026). All translations had good structural properties (root mean square error of approximation <0.05; comparative fit index [CFI], ≥0.899; and Tucker-Lewis index, ≥0.889). Full measurement invariance was observed between translations (ΔCFI ≤ 0.01) with metric invariance between translations and original (lowest ΔCFI = 0.022 between fully constrained models and models with free intercepts). Item characteristic curve analyses revealed no significant differences. This is the first experimental evidence that back-translation has moderate impact, whereas expert committee helps to ensure accurate content. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Multichannel MAC Layer In Mobile Ad—Hoc Network

    NASA Astrophysics Data System (ADS)

    Logesh, K.; Rao, Samba Siva

    2010-11-01

    This paper we presented the design objectives and technical challenges in Multichannel MAC protocols in Mobile Ad-hoc Network. In IEEE 802.11 a/b/g standards allow use of multiple channels, only a single channel is popularly used, due to the lack of efficient protocols that enable use of Multiple Channels. Even though complex environments in ad hoc networks require a combined control of physical (PHY) and medium access control (MAC) layers resources in order to optimize performance. And also we discuss the characteristics of cross-layer frame and give a multichannel MAC approach.

  4. Effect of Our Nation's Housing Policy on Homelessness. Hearing before the Ad Hoc Task Force on the Homeless and Housing of the Committee on the Budget, House of Representatives. One Hundredth Congress, Second Session.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on the Budget.

    According to Congressman Charles E. Schumer in his opening statement, the deqrease in Federal housing funds is inextricably linked to the increase in homelessness. Since 1981 the Reagan Administration has been systematically dismantling the nation's housing programs, leaving tens of thousands of low-income people homeless. In 1982 there were 1,088…

  5. Committee on Military Nutrition Research

    DTIC Science & Technology

    2007-01-01

    AD_________________ Award Number: DAMD17-99-1-9478 TITLE: COMMITTEE ON MILITARY NUTRITION ...COVERED (From - To) 01 Jun 99 – 31 Dec 06 4. TITLE AND SUBTITLE COMMITTEE ON MILITARY NUTRITION RESEARCH 5a. CONTRACT NUMBER...report presents the activities of the National Academy of Sciences/Institute of Medicine’s Committee on Military Nutrition Research (CMNR) for the

  6. The Acoustic Model Evaluation Committee (AMEC) Reports. Volume 3. Evaluation of the RAYMODE X Propagation Loss Model. Book 2. Appendices A-D

    DTIC Science & Technology

    1982-09-01

    2 of 3 The Acasstic Model Evaluation Committee (AMEC) Reports Vodlme III, Appendices A-i) Elakiaie of Me RAYAODE X f*W#ton Loss Model (U) Prepared by...Richard B. Laer, NORDP Numerical Modefa Division 11N Pylos of RAYNONE X (g) ’T evy •u v ,ap,.,,.,.nDTiC hpWor 1984;& AELE TEfTE Aft 12 W~ LAJ...Activity NSTL Station, Mississippi 39529 84 04 06 511 CONFIDENTIAL .%.. CONFIDENTIAL Appendix IliA. Accuracy Assessment of RAYMODE X Compared to SUDS

  7. Concise review: no breakthroughs for human mesenchymal and embryonic stem cell culture: conditioned medium, feeder layer, or feeder-free; medium with fetal calf serum, human serum, or enriched plasma; serum-free, serum replacement nonconditioned medium, or ad hoc formula? All that glitters is not gold!

    PubMed

    Mannello, Ferdinando; Tonti, Gaetana A

    2007-07-01

    The choice of an optimal strategy of stem cell culture is at the moment an impossible task, and the elaboration of a culture medium adapted to the production of embryonic and adult mesenchymal stem cells for the clinical application of cell therapy remains a crucial matter. To make an informed choice, it is crucial to not underestimate the theoretical health risk of using xenogenic compounds, to limit the immunological reactions once stem cells are transplanted, to not overestimate the controversial results obtained with human serum, plasma, and blood derivatives, as well as to carefully examine the pros and cons of serum-free and ad hoc formulation strategies; besides that, to also maintain multipotentiality, self-renewal, and transplantability. The extent to which we are able to achieve effective cell therapies will depend on assimilating a rapidly developing base of scientific knowledge with the practical considerations of design, delivery, and host response. Although clinical studies have already started, many questions remain unsolved, and concomitantly even more evidence on suitable and safe off-the-shelf products (mainly xeno-free) for embryonic and mesenchymal stem cells is cropping up, even though there should be no rush to enter the clinical stage while the underlying basic research is still not so solid; this solely will lead to high-quality translational research, without making blunders stemming from the assumption that all that glitters is not gold. Disclosure of potential conflicts of interest is found at the end of this article.

  8. A Discovery Process for Initializing Ad Hoc Underwater Acoustic Networks

    DTIC Science & Technology

    2008-12-01

    Bay (near the Seaweb network gateway node). ..................................................................... 15 Figure 11. Bellhop eigenray ...compute the eigenray traces and channel impulse response using code from Torres [18] that employs a Bellhop Gaussian beam tracing acoustic propagation...model. Figure 11 depicts the eigenray traces and channel impulse response for the Halifax trial environment with a transmit frequency of 12 kHz, water

  9. ICTNET at Web Track 2012 Ad-hoc Task

    DTIC Science & Technology

    2012-11-01

    Model and use it as baseline this year. 3.2 Learning to rank Learning to rank (LTR) introduces machine learning to retrieval ranking problem. It...Yoram Singer. An efficient boosting algorithm  for  combining preferences [J]. The Journal of  Machine   Learning  Research. 2003. 

  10. GBSFP: General Bluetooth Scatternet Formation Protocol for Ad Hoc Networking

    NASA Astrophysics Data System (ADS)

    Lim, Chaegwon; Huh, Myung-Sun; Choi, Chong-Ho; Jeong, Gu-Min

    Recently, bluetooth technology has become widely prevalent so that many laptops and mobile phones are equipped with bluetooth capability. In order to meet the increasing demand to interconnect these devices a new scatternet formation protocol named GBSFP (General Bluetooth Scatternet Formation Protocol) is proposed in this paper. GBSFP is the result of efforts to overcome the two major limitations of the legacy scatternet formation protocols as regards their real implementation, that all of the nodes should be within the Bluetooth communication range or that they should be time synchronized. In GBSFP, a node goes through three phases; 1) the Init phase to establish a bluetooth link to as many of its neighbors as possible, 2) the Ready phase to determine the role of each node, i.e., master or slave, and remove any unnecessary bluetooth links, and 3) the Complete phase to finalize the formation of the scatternet and begin data transmission. The simulation results show that GBSFP provides higher connectivity in many scenarios compared with BTCP and BlueStars.

  11. Credible Mobile and Ad Hoc Network Simulation-Based Studies

    DTIC Science & Technology

    2006-10-26

    packet radio. In Proceed- ings of the 9th ARRL /CRRL Amateur Radio Computer Networking Conference, pages 134-140, 1990. [45] H. Kee. NAM support for...Selected Areas in Communications (JSAC), pages 1335-1346, 2004. [102] P. Welch. The Computer Performance Modeling Handbook , chapter The Statis- tical

  12. Enabling Secure High-Performance Wireless Ad Hoc Networking

    DTIC Science & Technology

    2003-05-29

    extremely vulnerable to this attack . For example, OLSR and TBRPF use HELLO packets for neighbor detection, so if an attacker tunnels through a wormhole to...security. In particular, when an attacker is present in the network, a protocol that provides security against such an attacker should provide better...better than in insecure protocol when the network is under attack . As a network experiences attack , a secure network routing protocol may continue to

  13. Cross-Layered Security Analysis of Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-12-01

    protocols and link state routing (e.g. secure OLSR ) versus distance vector routing (e.g. SAODV). Some of the routing attacks are launched from the MAC...that pose the greatest security threats when controlled by the adversary. 3.1 Outsiders Outsiders are attackers that do not have any compromised...attempt to jam the communications channel, they can create a wormhole, and as an extreme attack , we assume they can eliminate nodes from the network

  14. Attaining Realistic Simulations of Mobile Ad-hoc Networks

    DTIC Science & Technology

    2010-06-01

    other peer nodes for routing to the end destination introduces the potential for man in the middle attacks . This means a malicious node could easily...One project was completed by Joachim Klein as a Master’s Thesis to create a Click implementation of Optimized Link State Routing ( OLSR ) [22]. Klein...created new elements within Click in order to route packets according to the OLSR specification. He validated his implementation by evaluating the

  15. A Survey on Trust Management for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2011-11-01

    a survey of trust management schemes developed for MANETs and discuss generally accepted classifications, potential attacks , performance metrics, and...restricted but security vulnerability is relatively high. III. CLASSIFICATIONS, POTENTIAL ATTACKS , AND METRICS FOR MANET TRUST MANAGEMENT This section...discusses classifications, attacks and perfor- mance metrics for MANET trust management. Before review- ing the literature, we would like to clarify some

  16. Ad Hoc Network Architecture for Multi-Media Networks

    DTIC Science & Technology

    2007-12-01

    Ethernet traffic while 1.9On  characterizes video traffic. These four parameters are in the range of self-similarity (i.e. , H is the Hurst ...For self-similar traffic,  falls in the range of 1 2  [24], which is related to . H is the Hurst parameter given in Equation 0.5 1H  (3.4...2y x , which is the exponent of  1 r , can be separated into 1 2y x     . Thus, Equation (4.2) is the new equation used to compute and . In

  17. Reinforcement learning for routing in cognitive radio ad hoc networks.

    PubMed

    Al-Rawi, Hasan A A; Yau, Kok-Lim Alvin; Mohamad, Hafizal; Ramli, Nordin; Hashim, Wahidah

    2014-01-01

    Cognitive radio (CR) enables unlicensed users (or secondary users, SUs) to sense for and exploit underutilized licensed spectrum owned by the licensed users (or primary users, PUs). Reinforcement learning (RL) is an artificial intelligence approach that enables a node to observe, learn, and make appropriate decisions on action selection in order to maximize network performance. Routing enables a source node to search for a least-cost route to its destination node. While there have been increasing efforts to enhance the traditional RL approach for routing in wireless networks, this research area remains largely unexplored in the domain of routing in CR networks. This paper applies RL in routing and investigates the effects of various features of RL (i.e., reward function, exploitation, and exploration, as well as learning rate) through simulation. New approaches and recommendations are proposed to enhance the features in order to improve the network performance brought about by RL to routing. Simulation results show that the RL parameters of the reward function, exploitation, and exploration, as well as learning rate, must be well regulated, and the new approaches proposed in this paper improves SUs' network performance without significantly jeopardizing PUs' network performance, specifically SUs' interference to PUs.

  18. Robust Connectivity in Sensory and Ad Hoc Network

    DTIC Science & Technology

    2011-02-01

    known that, for a scalar Gaussian MAC, orthogonal transmissions, e.g., frequency division multiple access ( FDMA ) or time division multiple access...TDMA) under an average power constraint, can achieve the sum capacity [11]. As such, although FDMA and TDMA is suboptimal in terms of the entire...proportional singular values, well aligned singular vectors and appropriate power constraints in order for FDMA /TDMA to achieve the sum capacity

  19. Mobile Ad Hoc Networks: An Evaluation of Smartphone Technologies

    DTIC Science & Technology

    2011-10-01

    Protocol (ARP) caches or Domain Name Services (DNS) caches . 2.1 Co-located Networks Returning to the example of the DWAN computers present in most CF...message to build a table mapping Host A’s IP and MAC address and then attempts to determine whether or not it has cached the information being requested by...to the switch. The switch checks the destination address of the reply, and compares it against the cached list of addresses. The switch cached Host A’s

  20. Report of the Ad Hoc Group for Irradiated Food Program

    DTIC Science & Technology

    1975-05-01

    food irradiation technology. The last briefer of this session was from the Energy Research and Development Administration, who monitors the...34remnants" of the Atomic Energy Commissions low-dosti irradiation program (Memoranduum For Record at Appendix F). In addition to inputs from these meetings...Agriculture, and State; the Energy Research and Development Administration; the National Science Foundation; the International Congress of Radiation

  1. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2007-08-01

    In both cases the impact of jamming and hostile intercept is being considered. The possibility of hostile action to deny services or exploit the...network accessing to a common access point. We see that the ace-only scheme is ur future plan includes orks under partial loading (as opposed to...time scheme and the sp remarkable. Future plan : O • Effect of channel estimation errors on throughput of large networks • Fundamental understanding

  2. Device Discovery in Frequency Hopping Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-09-01

    for implementing PANs [Blu01] [Blu03]. It is a popular protocol with 40 million Bluetooth-enabled phones shipped worldwide and over 1,000 new BT...Thesis, Blekinge Institute of Technology, Available: http://www.inst-informatica.pt/v20/cid/ biblioteca digital/telecomunicacoes

  3. Space-Time Processing for Tactical Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-05-01

    Communications, Vol. 57, No. 9, pp. 2528-2533, September, 2009 Michael Jensen B. T. Quist and M. A. Jensen, “Optimal antenna radiation characteristics for...and formulates the antennas that optimize the diversity gain for those average propagation characteristics . In the first solution to this problem... characteristics of the time-varying MIMO channel in different environments and captured the observed behaviors in stochastic models. This has

  4. Network Management System for Tactical Mobile Ad Hoc Network Segments

    DTIC Science & Technology

    2011-09-01

    Protocol UFO UHF Follow-On UHF Ultra High Frequency USB Universal Serial Bus VHF Very High Frequency VIRT Valuable Information at the Right Time...military satellite system known as the UHF Follow-on system ( UFO ) only provides capacity for 600 concurrent users. DoD users also have commercial

  5. Ad hoc methods for accurate determination of Bader's atomic boundary

    NASA Astrophysics Data System (ADS)

    Polestshuk, Pavel M.

    2013-08-01

    In addition to the recently published triangulation method [P. M. Polestshuk, J. Comput. Chem. 34, 206 (2013)], 10.1002/jcc.23121, two new highly accurate approaches, ZFSX and SINTY, for the integration over an atomic region covered by a zero-flux surface (zfs) were developed and efficiently interfaced into the TWOE program. ZFSX method was realized as three independent modules (ZFSX-1, ZFSX-3, and ZFSX-5) handling interatomic surfaces of a different complexity. Details of algorithmic implementation of ZFSX and SINTY are discussed. A special attention to an extended analysis of errors in calculations of atomic properties is paid. It was shown that uncertainties in zfs determination caused by ZFSX and SINTY approaches contribute negligibly (less than 10-6 a.u.) to the total atomic integration errors. Moreover, the new methods are able to evaluate atomic integrals with a reasonable time and can be universally applied for the systems of any complexity. It is suggested, therefore, that ZFSX and SINTY can be regarded as benchmark methods for the computation of any Quantum Theory of Atoms in Molecules atomic property.

  6. Sensor Sharing in Mobile Ad-Hoc Networks

    ERIC Educational Resources Information Center

    Mitra, Pramita

    2013-01-01

    Today's modern mobile devices (such as smartphones and tablets) present great potential for growth of many novel, powerful, but also highly demanding applications. However, most mobile devices/users operate in isolation from one another, i.e., they are not aware of the presence of other devices in their proximity. There are numerous situations…

  7. Flow Control in Wireless Ad-Hoc Networks

    DTIC Science & Technology

    2009-01-01

    these mechanisms can be improved in order to fine-tune TCP under various networking environments. Low, Paganini and Doyle [36] study TCP from a control...Derivative Securities, M. A. H. Dempster and S. R. Pliska, Eds., vol. 16. Cambridge University Press , 1997, pp. 504–527. [30] KUSHNER, H. J., AND DIMASI...wireless networks: Optimality and stability. IEEE Trans- actions on Information Theory 55, 9 (Sept. 2009), 4087–4098. 76 [36] LOW, S. H., PAGANINI , F

  8. Source Authentication for Multicast in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2003-01-01

    Chapter 1 Introduction A mobile adhoc network (MANET) [1, 2, 3, 4, 5, 6] is a dynamically changing multi-hop network created by a set of wireless mobile...synchronization error. The time-servers distributed across the network should be synchronized with each other. The mobility and adhoc -ness involved in MANETs make...need be, one can deploy more UAVs to span the entire network , in which case, the routing between the UAVs is bi-directional. The number of UAVs is

  9. Rural nurse to nurse practitioner: an ad hoc process.

    PubMed

    Carryer, Jenny; Boddy, Julie; Budge, Claire

    2011-03-01

    Despite a 10-year history of nurse practitioner (NP) development in New Zealand (NZ) there is no formalised or universal process for ensuring the transition of willing nurses to NP status. This unmet need is of particular interest in the rural context where workforce issues are paramount. The aim of this study was to explore the transition from rural nurse to NP in NZ. A qualitative descriptive survey was sent to all NZ nurses with a rural address. Ninety-two questionnaires were returned, of which 21 respondents were working in a rural location and aiming to become an NP. Data analysis included description of demographic data and thematic analysis of open-ended question responses. Four themes encompassed the experiences of the 21 potential NP candidates: uncertainty about opportunities for employment as an NP and legislative and funding barriers for NP practice; support or resistance from GPs and nurse colleagues, self-doubt, and the importance of mentoring; difficulties with the NP authorisation process; and meeting the NP competencies within the challenges imposed by rural location. At the systems level of workforce design, stronger linkages between policy development, investment, employment creation, funding streams, professional regulation and overall communication require attention.

  10. Army Science Board Ad Hoc Subgroup Report, Manning Army Systems

    DTIC Science & Technology

    1982-09-01

    Jr. (USMC-Ret) Dr. K. C. Emerson Dr. P. Phillip Sidwell Dr. John R. Tooley SECURITY CLASSIFICATION OF THIS PAGEOWi"! Data Et .1 I DEPARTMENT OF...Drive Sanibel, FL 33957 (813) 472-9156 Dr. P. Phillip Sidwell Post Office Box 88531 Atlanta, GA 30338 (404) 394-2548 Dr. John R. Tooley ...30338 . Dr. John R. Tooley * Dean, School of Engineering and Applied Science University of Evansvllle Post Office Box 329 Evansvllle, IN 47702 DIST-4 1 •I

  11. Applying Ad Hoc Institutional Research Findings to College Strategic Planning

    ERIC Educational Resources Information Center

    Clagett, Craig A.

    2004-01-01

    Environmental scanning, enrollment forecasting, budget analyses, and institutional effectiveness assessment are examples of the explicit contributions institutional research offices make to campus strategic planning.

  12. Secure Ad Hoc Networking on an Android Platform

    DTIC Science & Technology

    2014-05-01

    Haselsteiner, E. & Breitfuß, K. (2006) Security in near field communication (nfc), in Workshop on RFID Security RFIDSec. Khan, S., Banuri, S. H. K...security on mobile phones, in Workshop on RFID Security–RFIDSec09. UNCLASSIFIED 21 DSTO–TN–1390 UNCLASSIFIED Appendix A Certificate Authority Key

  13. Supporting Secure, AD HOC Joins for Tactical Networks

    DTIC Science & Technology

    2002-05-07

    ftp.isi.edu/in-notes/ rfc2501.txt (20SEP01). [4] Deitel , Harvery M. and Paul J. Deitel . Java : How to Program 3rd Edition. (Prentice Hall: New...52 7.3.1 Java Run Time Benchmarking . . . . . . . . . . . . . . . . . . . . . . 52 7.3.2 A More Precise Measurement Method...timeline. Appendices B and C are the Java source files AuthenticationClient.java and AuthenticationService.java respectfully, that outline our

  14. Applying Ad Hoc Institutional Research Findings to College Strategic Planning

    ERIC Educational Resources Information Center

    Clagett, Craig A.

    2004-01-01

    Environmental scanning, enrollment forecasting, budget analyses, and institutional effectiveness assessment are examples of the explicit contributions institutional research offices make to campus strategic planning.

  15. Mobile Ad-Hoc Networking on Android Devices

    DTIC Science & Technology

    2014-03-01

    2012 Android and iOS devices dominated the market share with 75.0% and 14.9%, respectively (5). This strongly suggested Android devices as our platform...networks, it lacks the ability to create them. This lack of ability and the fact that the Android operating system is open source, while iOS is very...Battlefield Scenarios; U.S. Army Research Laboratory: Aberdeen Proving Ground, MD To be published in 2014. 4. Kerr, D. Android beats iOS 5-to-1 in Q3

  16. Reinforcement Learning for Routing in Cognitive Radio Ad Hoc Networks

    PubMed Central

    Al-Rawi, Hasan A. A.; Mohamad, Hafizal; Hashim, Wahidah

    2014-01-01

    Cognitive radio (CR) enables unlicensed users (or secondary users, SUs) to sense for and exploit underutilized licensed spectrum owned by the licensed users (or primary users, PUs). Reinforcement learning (RL) is an artificial intelligence approach that enables a node to observe, learn, and make appropriate decisions on action selection in order to maximize network performance. Routing enables a source node to search for a least-cost route to its destination node. While there have been increasing efforts to enhance the traditional RL approach for routing in wireless networks, this research area remains largely unexplored in the domain of routing in CR networks. This paper applies RL in routing and investigates the effects of various features of RL (i.e., reward function, exploitation, and exploration, as well as learning rate) through simulation. New approaches and recommendations are proposed to enhance the features in order to improve the network performance brought about by RL to routing. Simulation results show that the RL parameters of the reward function, exploitation, and exploration, as well as learning rate, must be well regulated, and the new approaches proposed in this paper improves SUs' network performance without significantly jeopardizing PUs' network performance, specifically SUs' interference to PUs. PMID:25140350

  17. Measuring Human Performance in a Mobile Ad Hoc Network (MANET)

    DTIC Science & Technology

    2010-06-01

    routing in a wireless mesh network test bed. Journal on Wireless Communi- cations and Networking , Vol 2007, Article ID 86510. Ikeda, M., L. Barolli, M...by wireless radios with limited band- width and no fixed infrastructure support. Instead of fixed network nodes, the MANET nodes will be dynamic...2006. Evaluation of packet latency in single and multi -hop WiFi wireless networks . In Proceedings of SPIE: Wireless sensing and processing,

  18. Research of ad hoc network based on SINCGARS network

    NASA Astrophysics Data System (ADS)

    Nie, Hao; Cai, Xiaoxia; Chen, Hong; Chen, Jian; Weng, Pengfei

    2016-03-01

    In today's world, science and technology make a spurt of progress, so society has entered the era of information technology, network. Only the comprehensive use of electronic warfare and network warfare means can we maximize their access to information and maintain the information superiority. Combined with the specific combat mission and operational requirements, the research design and construction in accordance with the actual military which are Suitable for the future of information technology needs of the tactical Adhoc network, tactical internet, will greatly improve the operational efficiency of the command of the army. Through the study of the network of the U.S. military SINCGARS network, it can explore the routing protocol and mobile model, to provide a reference for the research of our army network.

  19. An Alternative Paradigm for Routing in Wireless Ad Hoc Networks

    DTIC Science & Technology

    2004-12-01

    holes. The node construct is modeled as a point in space. The wormhole construct is modeled as a directed path be- tween two points in space...Nodes and the end nodes of wormholes are connected through wireless links. Links are inferred from the node states. The basic algorithm...the wormholes . Some potential states are listed in Table 1. In NSR, nodes discover the pathloss to their neighbors and disseminate this as a

  20. Sensor Sharing in Mobile Ad-Hoc Networks

    ERIC Educational Resources Information Center

    Mitra, Pramita

    2013-01-01

    Today's modern mobile devices (such as smartphones and tablets) present great potential for growth of many novel, powerful, but also highly demanding applications. However, most mobile devices/users operate in isolation from one another, i.e., they are not aware of the presence of other devices in their proximity. There are numerous situations…

  1. A Survey on Trust Management for Mobile Ad Hoc Networks

    DTIC Science & Technology

    2010-07-01

    negative consequences if the expectation is not conrmed than positive consequences if it is conrmed. In addition, Hardin [27] and Rotter [28...insights provided by our internal ARL staff including Eliza- beth Bowman, Kevin Chan, Natalie Ivanic, and Brian Rivera. The authors also give special...Processes, Carl Hovland Memorial Lectures Series, New Haven and London: Yale University Press, 1973. [27] R. Hardin , “The Street-Level Epistemology of

  2. Ad hoc methods for accurate determination of Bader's atomic boundary.

    PubMed

    Polestshuk, Pavel M

    2013-08-07

    In addition to the recently published triangulation method [P. M. Polestshuk, J. Comput. Chem. 34, 206 (2013)], two new highly accurate approaches, ZFSX and SINTY, for the integration over an atomic region covered by a zero-flux surface (zfs) were developed and efficiently interfaced into the TWOE program. ZFSX method was realized as three independent modules (ZFSX-1, ZFSX-3, and ZFSX-5) handling interatomic surfaces of a different complexity. Details of algorithmic implementation of ZFSX and SINTY are discussed. A special attention to an extended analysis of errors in calculations of atomic properties is paid. It was shown that uncertainties in zfs determination caused by ZFSX and SINTY approaches contribute negligibly (less than 10(-6) a.u.) to the total atomic integration errors. Moreover, the new methods are able to evaluate atomic integrals with a reasonable time and can be universally applied for the systems of any complexity. It is suggested, therefore, that ZFSX and SINTY can be regarded as benchmark methods for the computation of any Quantum Theory of Atoms in Molecules atomic property.

  3. Resource Management in Multi-hop Ad Hoc Networks

    DTIC Science & Technology

    1999-11-21

    Communications Review, 27(5), 1996. Read from http://www.ece.orst.edu/s̃ingh/papers.html. [8] M. Scott Corson and Anthony Ephremides. A Distributed Routing...France, October 1997. [32] Vincent D. Park and M. Scott Corson . A Highly Adaptive Distributed Routing Algorithm for Mobile Wireless Networks. In...Proceedings of INFOCOM’97, pages 1405–1413, April 1997. [33] Vincent D. Park and M. Scott Corson . A Performance Comparison of TORA and Ideal Link State

  4. Performance Analysis of Mobile Ad Hoc Networking Routing Protocols

    DTIC Science & Technology

    2004-12-01

    process of establishing the DAG is similar to the query and reply process as proposed in a light-weight mobile routing (LMR) [ Corson 1995]. Upon link...2004. [RIP RFC] RIP Version 2 RFC Website. http://www.faqs.org/rfcs/rfc2453.html accessed on 1 October 2004. [Royer 1999] Elizabeth M. Royer & C

  5. Self-organized Anonymous Authentication in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Freudiger, Julien; Raya, Maxim; Hubaux, Jean-Pierre

    Pervasive communications bring along new privacy challenges, fueled by the capability of mobile devices to communicate with, and thus “sniff on”, each other directly. We design a new mechanism that aims at achieving location privacy in these forthcoming mobile networks, whereby mobile nodes collect the pseudonyms of the nodes they encounter to generate their own privacy cloaks. Thus, privacy emerges from the mobile network and users gain control over the disclosure of their locations. We call this new paradigm self-organized location privacy. In this work, we focus on the problem of self-organized anonymous authentication that is a necessary prerequisite for location privacy. We investigate, using graph theory, the optimality of different cloak constructions and evaluate with simulations the achievable anonymity in various network topologies. We show that peer-to-peer wireless communications and mobility help in the establishment of self-organized anonymous authentication in mobile networks.

  6. Addressing barriers to perinatal care: a case study of the Access to Maternity Care Committee in Washington State.

    PubMed Central

    Schleuning, D; Rice, G; Rosenblatt, R A

    1991-01-01

    Access to obstetrical services has deteriorated in recent years, as large numbers of physicians have discontinued or restricted obstetrical practice. In Washington State, one response to this access crisis has been the establishment of the Access to Maternity Care Committee (AMCC), an ad hoc group composed primarily of private sector obstetrical providers and representatives of State government responsible for the delivery of health care to women and children. The major objectives of the AMCC is to improve access to obstetrical services for socially vulnerable women, both rural inhabitants and the medically indigent. The committee has been successful in serving as a forum in which to resolve many of the administrative problems that have arisen between private sector obstetrical providers and the State's Medicaid Program, the major source of payment for the one-third of pregnant women who are medically indigent. Building upon the trust that the committee members developed in working together, the AMCC served as a major force in persuading the State legislature to expand substantially its investment in perinatal care by increasing Medicaid eligibility, raising provider reimbursement, and improving social service for pregnant women. Such ad hoc coalitions between the private and public sector may be quite effective in addressing obstetrical access problems in other States. PMID:1899939

  7. Addressing barriers to perinatal care: a case study of the Access to Maternity Care Committee in Washington State.

    PubMed

    Schleuning, D; Rice, G; Rosenblatt, R A

    1991-01-01

    Access to obstetrical services has deteriorated in recent years, as large numbers of physicians have discontinued or restricted obstetrical practice. In Washington State, one response to this access crisis has been the establishment of the Access to Maternity Care Committee (AMCC), an ad hoc group composed primarily of private sector obstetrical providers and representatives of State government responsible for the delivery of health care to women and children. The major objectives of the AMCC is to improve access to obstetrical services for socially vulnerable women, both rural inhabitants and the medically indigent. The committee has been successful in serving as a forum in which to resolve many of the administrative problems that have arisen between private sector obstetrical providers and the State's Medicaid Program, the major source of payment for the one-third of pregnant women who are medically indigent. Building upon the trust that the committee members developed in working together, the AMCC served as a major force in persuading the State legislature to expand substantially its investment in perinatal care by increasing Medicaid eligibility, raising provider reimbursement, and improving social service for pregnant women. Such ad hoc coalitions between the private and public sector may be quite effective in addressing obstetrical access problems in other States.

  8. [Bioethics committees].

    PubMed

    Lanzilota, Alicia

    2007-01-01

    The present paper exposes a brief historical route showing the context of the Ethics Committee developing. The moral conflicts in clinical care that doctors had to face with the introduction of the new technologies, the creation of the first clinical committees in USA and the abuses in the biomedical investigations, determined the establishment of ethical guidelines and settled institutional review committees for its control. First Bioethics Committees in Argentina were established by adopting the US Ethic Committees model. The proliferation of hospital ethics committees was related to local regulations requirements. Current regulations. Bioethics Committees in Buenos Aires City, through the data of a survey.

  9. Conference Committees: Conference Committees

    NASA Astrophysics Data System (ADS)

    2009-09-01

    International Programm Committee (IPC) Harald Ade NCSU Sadao Aoki University Tsukuba David Attwood Lawrence Berkeley National Laboratory/CXRO Christian David Paul Scherrer Institut Peter Fischer Lawrence Berkeley National Laboratory Adam Hitchcock McMaster University Chris Jacobsen SUNY, Stony Brook Denis Joyeux Lab Charles Fabry de l'Institut d'Optique Yasushi Kagoshima University of Hyogo Hiroshi Kihara Kansai Medical University Janos Kirz SUNY Stony Brook Maya Kiskinova ELETTRA Ian McNulty Argonne National Lab/APS Alan Michette Kings College London Graeme Morrison Kings College London Keith Nugent University of Melbourne Zhu Peiping BSRF Institute of High Energy Physics Francois Polack Soleil Christoph Quitmann Paul Scherrer Institut Günther Schmahl University Göttingen Gerd Schneider Bessy Hyun-Joon Shin Pohang Accelerator Lab Jean Susini ESRF Mau-Tsu Tang NSRRC Tony Warwick Lawrence Berkeley Lab/ALS Local Organizing Committee Christoph Quitmann Chair, Scientific Program Charlotte Heer Secretary Christian David Scientific Program Frithjof Nolting Scientific Program Franz Pfeiffer Scientific Program Marco Stampanoni Scientific Program Robert Rudolph Sponsoring, Financials Alfred Waser Industry Exhibition Robert Keller Public Relation Markus Knecht Computing and WWW Annick Cavedon Proceedings and Excursions and Accompanying Persons Program Margrit Eichler Excursions and Accompanying Persons Program Kathy Eikenberry Excursions and Accompanying Persons Program Marlies Locher Excursions and Accompanying Persons Program

  10. 76 FR 24957 - Nineteenth Meeting: RTCA Special Committee 203: Unmanned Aircraft Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-03

    ... Workgroup Sense and Avoid Workgroup Ad Hoc Group Report Architecture Group Report Modeling and Simulation... Engineering Workgroup OV6c Continued Control and Communications Workgroup Modeling and Simulation...

  11. Hairy AdS solitons

    NASA Astrophysics Data System (ADS)

    Anabalón, Andrés; Astefanesei, Dumitru; Choque, David

    2016-11-01

    We construct exact hairy AdS soliton solutions in Einstein-dilaton gravity theory. We examine their thermodynamic properties and discuss the role of these solutions for the existence of first order phase transitions for hairy black holes. The negative energy density associated to hairy AdS solitons can be interpreted as the Casimir energy that is generated in the dual filed theory when the fermions are antiperiodic on the compact coordinate.

  12. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-07

    ... Group ] 7, Antenna (GPS Antenna), Colson Board Room. Plenary Session--See Agenda Below Friday, June 17.../Antennas (WG-7). Review of EUROCAE Activities. ADS-B GAP Analysis Ad Hoc--Report. Assignment/Review...

  13. An ethics for the living world: operation methods of Animal Ethics Committees in Italy.

    PubMed

    Martini, Mariano; Penco, Susanna; Baldelli, Ilaria; Biolatti, Bartolomeo; Ciliberti, Rosagemma

    2015-01-01

    Coinciding with the recent implementation in Italy of the "Directive 2010/63/EU, regarding the protection of animals used for scientific purposes", the Authors would like to analyse the topic of the introduction of ethical committees for animal experimentation in Italy. This paper furthermore aims to underline some critical aspects concerning the actions taken by Italian institutions to comply with the provisions of EU. The implementation of the recent Italian law (Decreto Legislativo n. 26 on 4 March 2014 Implementation of the Directive 2010/63/EU on the protection of animals used for scientific purposes) leans towards a restrictive interpretation of the European provisions about composition and responsibilities of "Ethical Committee for Animal Experimentation". In the composition of the bodies mentioned, we note a tendency to restrict the composition to few professional figures contemplated by Italian law, without guaranteeing the independence of each committee; also, an absence of hierarchical relationship between a research institution and his committee is apparent. Moreover, a critical aspect is the lack of decision-making powers of these new organisms in terms of ethical evaluation of protocols and research projects. What EU legislation imposes on the member states is to set up an animal-welfare body (art. 26). This represents a strong incentive for Italy to follow the steps of many other European Countries, where ad hoc ethical committees have been working for a long time. The proper functioning of these bodies may contribute to guarantee the safety and welfare of the animals inside the laboratories, and to balance the protection of animal life and the interests of research.

  14. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher,…

  15. 18 CFR 701.59 - Advisory committees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Advisory committees. 701.59 Section 701.59 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Headquarters Organization § 701.59 Advisory committees. The Council may establish standing and ad...

  16. 18 CFR 701.59 - Advisory committees.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Advisory committees. 701.59 Section 701.59 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Headquarters Organization § 701.59 Advisory committees. The Council may establish standing and ad...

  17. 18 CFR 701.59 - Advisory committees.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Advisory committees. 701.59 Section 701.59 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Headquarters Organization § 701.59 Advisory committees. The Council may establish standing and ad...

  18. 18 CFR 701.59 - Advisory committees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Advisory committees. 701.59 Section 701.59 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Headquarters Organization § 701.59 Advisory committees. The Council may establish standing and ad...

  19. 18 CFR 701.59 - Advisory committees.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Advisory committees. 701.59 Section 701.59 Conservation of Power and Water Resources WATER RESOURCES COUNCIL COUNCIL ORGANIZATION Headquarters Organization § 701.59 Advisory committees. The Council may establish standing and ad...

  20. The Development Committee. Effective Committees. Board Basics.

    ERIC Educational Resources Information Center

    Evans, Gary

    1997-01-01

    A college or university governing board's development committee (or foundation board in a public institution) has both oversight of and broad responsibility for institutional fund-raising activities. Committee members have an additional role that colleagues on other committees do not--active participation in fund-raising. The committee sets goals,…

  1. Adding Value.

    ERIC Educational Resources Information Center

    Orsini, Larry L.; Hudack, Lawrence R.; Zekan, Donald L.

    1999-01-01

    The value-added statement (VAS), relatively unknown in the United States, is used in financial reports by many European companies. Saint Bonaventure University (New York) has adapted a VAS to make it appropriate for not-for-profit universities by identifying stakeholder groups (students, faculty, administrators/support personnel, creditors, the…

  2. 76 FR 71430 - Automatic Dependent Surveillance Broadcast (ADS-B)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-17

    ... a global strategy to proceed with ADS-B In while ensuring compatibility with the standards adopted... the ADS-B In Aviation Rulemaking Committee, Recommendations to Define a Strategy for Incorporating ADS... forum for the U.S. and international aviation community to define a strategy for incorporating ADS-B...

  3. PREFACE: Scientific Organising Committee Information

    NASA Astrophysics Data System (ADS)

    2015-06-01

    Edited by: Oliver Roberts Lorraine Hanlon Sheila McBreen Local Organising Committee: Oliver Roberts (Chair) Antonio Martin-Carrillo Lorraine Hanlon Sheila McBreen Alexey Uliyanov David Murphy Sinéad Hales Scientific Organising Committee:: Sheila McBreen, (UCD, Ireland) (Chair) Franco Camera (INFN-Milano, Italy) Nerine Cherepy (LLNL, USA) Jarek Glodo (RMD, USA) Lorraine Hanlon (UCD, Ireland) Paul Lecoq (CERN, Switzerland) Julie McEnery (NASA, USA) Oliver Roberts (UCD, Ireland) Anant Setlur, (GE, USA) Brian Shortt, (ESA, the Netherlands) Kenneth Stanton (UCD, Ireland)

  4. Mass Casualty Incident Management Preparedness: A Survey of the American College of Surgeons Committee on Trauma.

    PubMed

    Lewis, Aaron M; Sordo, Salvador; Weireter, Leonard J; Price, Michelle A; Cancio, Leopoldo; Jonas, Rachelle B; Dent, Daniel L; Muir, Mark T; Aydelotte, Jayson D

    2016-12-01

    Mass casualty incidents (MCIs) are events resulting in more injured patients than hospital systems can handle with standard protocols. Several studies have assessed hospital preparedness during MCIs. However, physicians and trauma surgeons need to be familiar with their hospital's MCI Plan. The purpose of this survey was to assess hospitals' and trauma surgeon's preparedness for MCIs. Online surveys were e-mailed to members of the American College of Surgeons committee on Trauma Ad Hoc Committee on Disaster and Mass Casualty Management before the March 2012 meeting. Eighty surveys were analyzed (of 258). About 76 per cent were American College of Surgeons Level I trauma centers, 18 per cent were Level II trauma centers. Fifty-seven per cent of Level I and 21 per cent of Level II trauma centers had experienced an MCI. A total of 98 per cent of respondents thought it was likely their hospital would see a future MCI. Severe weather storm was the most likely event (95%), followed by public transportation incident (86%), then explosion (85%). About 83 per cent of hospitals had mechanisms to request additional physician/surgeons, and 80 per cent reported plans for operative triage. The majority of trauma surgeons felt prepared for an MCI and believed an event was likely to occur in the future. The survey was limited by the highly select group of respondents and future surveys will be necessary.

  5. Hurricane Katrina: Barriers to Mental Health Services for Children Persist in Greater New Orleans, Although Federal Grants Are Helping to Address Them. Testimony before the Ad Hoc Subcommittee on Disaster Recovery, Senate Committee on Homeland Security and Governmental Affairs. GAO-09-935T

    ERIC Educational Resources Information Center

    Bascetta, Cynthia A.

    2009-01-01

    The greater New Orleans area has yet to fully recover from the effects of Hurricane Katrina, which made landfall on August 29, 2005. One issue of concern in the recovery is the availability of mental health services for children. It is estimated that in 2008 about 187,000 children were living in the greater New Orleans area. Many children in the…

  6. Influenza Pandemic: Continued Focus on the Nation's Planning and Preparedness Efforts Remains Essential. Testimony before the Ad Hoc Subcommittee on State, Local, and Private Sector Preparedness and Integration, Senate Committee on Homeland Security and Governmental Affairs. GAO-09-760T

    ERIC Educational Resources Information Center

    Steinhardt, Bernice

    2009-01-01

    As the recent outbreak of the H1N1 (swine flu) virus underscores, an influenza pandemic remains a real threat to our nation and to the world. Over the past 3 years, the US Government Accountability Office (GAO) has conducted a body of work to help the nation better prepare for a possible pandemic. In a February 2009 report, GAO synthesized the…

  7. Maritime Education and Training Miscellaneous. Hearings Before the Ad Hoc Select Subcommittee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries. House of Representatives, Ninety-Sixth Congress (December 6, 11, 1979, February 25, April 28, 1980).

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

    The three days of House subcommittee hearings reported in this transcript deal with the proposed Maritime Education and Training Act, H.R. 5451 and the Maritime Education and Training Elements of Maritime Appropriations Authorization Act--H.R. 6554. The primary goal of the legislation is to provide for the supply of merchant marine officers from…

  8. Executive committee

    NASA Astrophysics Data System (ADS)

    Xiao, Guoqing; Cai, Xiaohong; Ding, Dajun; Ma, Xinwen; Zhao, Yongtao

    2014-04-01

    ChairVice Chair Toshiyuki AzumaRoberto Rivarola Atomic, Molecular & Optical Physics LabUniversidad Nacional de Rosario and Advanced Science InstituteInstituto de Fisica Rosario RIKEN, JapanRosario, Argentina SecretaryMembers Dominique VernhetJoachim Burgdörfer, Austria Institut des NanoSciences de Paris Birgit Lohmann, Australia Université Pierre et Marie Curie Hossein Sadeghpour, USA Paris, FranceThomas Stöhlker, Germany Past ChairJim McCann, UK Barry DunningGuoqing Xiao, China Physics & AstronomyXiaohong Cai, China Rice University, HoustonXinwen Ma, China Texas, USAYongtao Zhao, China TreasurerFernando Martin, Spain Henrik CederquistLuis Mendez, Spain Alba Nova University CenterAnatoli Kheifets, Australia Stockholm University Stockholm, Sweden Details of the general committee are available in the PDF

  9. Conference Committees

    NASA Astrophysics Data System (ADS)

    2015-11-01

    Scientific Committee Silvia Arrese-Igor Irigoyen (CFM, CSIC - UPV/EHU, Donostia), Javier Campo (ICMA-CSIC, Zaragoza), Carlos Frontera (ICMAB-CSIC, Barcelona), Victoria García Sakai (ISIS, Chilton), Cristina Gómez-Polo (UPNa, Pamplona), Miguel Ángel González (ILL, Grenoble), Pedro Gorría (Universidad Oviedo), Jon Gutiérrez Echevarría (EHU/UPV, Bilbao), J. Iñaki Pérez Landazábal (UPNa, Pamplona), Vicente Recarte (UPNa, Pamplona), Jesús Ruíz Hervías (UPM, Madrid), Vicente Sánchez-Alarcos (UPNa, Pamplona), Antonio Urbina (UPC, Cartagena) Organizing Committee J. Iñaki Pérez Landazábal (Co-Chair), Vicente Recarte ( Co-Chair), Cristina Gómez-Polo, Silvia Larumbe Abuin, Vicente Sánchez-Alarcos Editors of the Proceedings J. Iñaki Pérez Landazábal, Vicente Recarte Plenary speakers Charles Simon (Institut Laue-Langevin, Grenoble, France), Miguel Angel Alario Franco (Universidad Complutense, Madrid, Spain), Dieter Richter (Jülich Centre for Neutron Science, Jülich, Germany), James Yeck (European Spallation Source, Lund, Sweden) Invited speakers Manu Barandiarán (BCMaterials & EHU/UPV), Arantxa Arbe (MFC, CSIC- UPV/EHU), José Luis Martínez (Consorcio ESS-Bilbao), Marta Castellote, IETcc-CSIC), Josep Lluis Tamarit (UPC), Diego Alba-Venero (ISIS), Elizabeth Castillo (CIC Energigune), Josu M. Igartua (EHU/UPV), Antonio Dos Santos (UPM), Alex Masalles (Museu Nacional d'Art de Catalunya), José Abad (UPCT), Claudia Mondelli (ILL), Oscar Fabelo (ILL), Aurora Nogales (IEM-CSIC), Jesús Rodríguez (UC), Gerardo

  10. The Investment Committee. AGB Effective Committee Series

    ERIC Educational Resources Information Center

    Yoder, Jay A.

    2011-01-01

    This publication is part of an AGB series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices included in this text support the objectives of board committees:…

  11. The Investment Committee. AGB Effective Committee Series

    ERIC Educational Resources Information Center

    Yoder, Jay A.

    2011-01-01

    This publication is part of an AGB series devoted to strengthening the role of key standing committees of governing boards. While there is no optimum committee system for institutions of higher education, certain principles, practices, and procedures prevail. The best practices included in this text support the objectives of board committees:…

  12. 78 FR 40698 - Caribbean Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-08

    ... (Council) Ad Hoc Committee on Socio-Economic Impact of Yearly Closures will hold a meeting. DATES: The..., Puerto Rico 00918, telephone: (787) 766-5926. SUPPLEMENTARY INFORMATION: The Ad Hoc Committee on...

  13. 78 FR 34654 - New England Fishery Management Council (NEFMC); Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... Management Council (Council) is scheduling a public meeting of its Ad hoc Sturgeon Committee (SSC) to... NEFMC's Ad hoc Sturgeon Committee will meet to review the Draft Endangered Species Act Section...

  14. Citizen Advisory Committees.

    ERIC Educational Resources Information Center

    Miller, Leann R.

    This guide, describing community involvement through citizen advisory committees, is a summary of the literature on such committees. Its main concern is district committees created by school boards. Citations in the bibliography contain all points of view on committees and present many alternatives on most of the topics covered in the guide.…

  15. Student Affairs Committee.

    ERIC Educational Resources Information Center

    Goodale, Thomas G.

    1984-01-01

    The agenda, structure, and responsibilities of a board of trustees standing committee--the campus student affairs committee--are discussed. The size, selection, and rotation of student affairs committee members will vary with the traditions and policies of the individual institution. If possible, the committee should include students among its…

  16. Myrrha, Technology Development for the Realisation of ADS in Eu:. Current Status & Prospects for Realisation

    NASA Astrophysics Data System (ADS)

    Fernandez, R.; Abderrahim, H. Aït; Baeten, P.; de Bruyn, D.; Maes, D.; Mazouzi, A. Al; Ariën, B.; Malambu, E.; Schuurmans, P.; Schyns, M.; Sobolev, V.; van den Eynde, G.; Vandeplassche, D.

    2010-06-01

    The coupling between an accelerator, a spallation target and a subcritical core has been studied for the first time at SCK•CEN in collaboration with Ion Beam Applications (IBA, Louvain-la-Neuve) in the frame of the ADONIS project (1995-1997). ADONIS was a small irradiation facility, based on the ADS concept, having a dedicated objective to produce radioisotopes for medical purposes and more particularly 99Mo as a fission product from highly enriched 235U (HEU) fissile targets. The ad-hoc scientific advisory committee recommended extending the purpose of the ADONIS machine to become a Material Testing Reactor (MTR) for material and fuel research, to study the feasibility of transmutation of the minor actinides and to demonstrate at a reasonable power scale the principle of the ADS. The project, since 1998 named MYRRHA, has then evolved to a larger installation. MYRRHA is now conceived as a flexible irradiation facility, able to work as an Accelerator Driven (subcritical mode) and in critical mode. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV systems, material developments for fusion reactors, radioisotope production for medical and industrial applications and industrial applications, such as Si-doping. MYRRHA will also demonstrate the ADS full concept by coupling the three components (accelerator, spallation target and subcritical reactor) at reasonable power level to allow operation feedback, scalable to an industrial demonstrator and allow the study of efficient transmutation of high-level nuclear waste. Since MYRRHA is based on the heavy liquid metal technology, the eutectic lead-bismuth, it will be able to significantly contribute to the development of Lead Fast Reactor Technology. Since MYRRHA will also be operated in critical mode, MYRRHA can even better play the role of European Technology Pilot Plant in the roadmap for LFR.

  17. Committee on Military Nutrition Research Activity Report 1986 - 1992.

    DTIC Science & Technology

    1992-06-29

    adequate to prevent significant hypohydration? Appendix G Summary and Recommendations from the Brief Report: Military Nutrition Initiatives 88 APPF_...AD-A252 884I HIIIElitEl111111ll1111lll COMMITTEE ON MILITARY NUTRITION RESEARCH DTIC- S ELECTE’ /JUL 1 41992. fox public zelease ond sle; itsd...SUBTITLE 5. FUNDING NUMBERS Committee on Military Nutrition Research DAMD17-86-G-6036 Activity Report 1986-1992 6. AUTHOR(S) work of: Committee on

  18. The role of curriculum committees in pharmacy education.

    PubMed

    Carter, Jean T; Draugalis, JoLaine R; Bruce, Susan P; Gonyeau, Michael R

    2011-10-10

    To conduct a follow-up survey of curriculum committee chairs in US colleges and schools of pharmacy to describe current committee structures and functions and determine whether changes have occurred over time. A descriptive cross-sectional study design using a 30-item survey instrument regarding the structure, function, and charges of curriculum committees was sent to 100 curriculum committee chairs. Several new variables were added to the questionnaire to explore the use of systematic reviews, oversight of experiential education, and the impact of accreditation standards on work focus. Eighty-five chairs responded. Curriculum committees are on average 1 person larger, less likely to have a student vote, more likely to have formal charges, and more likely to be involved in implementing an outcomes-based curriculum compared with 1994. Committees have shifted their work focus from review of curricular content to curricular revision. Curriculum committees continue to evolve as they respond to changes in pharmacy education and accreditation standards.

  19. Inter-Vehicular Ad Hoc Networks: From the Ground Truth to Algorithm Design and Testbed Architecture

    ERIC Educational Resources Information Center

    Giordano, Eugenio

    2011-01-01

    Many of the devices we interact with on a daily basis are currently equipped with wireless connectivity. Soon this will be extended to the vehicles we drive/ride every day. Wirelessly connected vehicles will form a new kind of network that will enable a wide set of innovative applications ranging from enhanced safety to entertainment. To…

  20. Receiver-Initiated Channel-Hopping for Ad-Hoc Networks

    DTIC Science & Technology

    2000-01-01

    SRMA (split-channel reservation multiple access) was first proposed by Kleinrock and Tobagi [15], including MACA [12], MACAW [2], IEEE 802.11 [1], and...Physical Layer (PHY) Specifications. IEEE, July 1996. [2] Bharghavan, V. and Demers, A. and Shenker, S. and Zhang, L. MACAW : A Media Access Protocol for