Science.gov

Sample records for access control mechanisms

  1. Logical Access Control Mechanisms in Computer Systems.

    ERIC Educational Resources Information Center

    Hsiao, David K.

    The subject of access control mechanisms in computer systems is concerned with effective means to protect the anonymity of private information on the one hand, and to regulate the access to shareable information on the other hand. Effective means for access control may be considered on three levels: memory, process and logical. This report is a…

  2. An Action-Based Fine-Grained Access Control Mechanism for Structured Documents and Its Application

    PubMed Central

    Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

    2014-01-01

    This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical. PMID:25136651

  3. Virus spreading in wireless sensor networks with a medium access control mechanism

    NASA Astrophysics Data System (ADS)

    Wang, Ya-Qi; Yang, Xiao-Yuan

    2013-04-01

    In this paper, an extended version of standard susceptible-infected (SI) model is proposed to consider the influence of a medium access control mechanism on virus spreading in wireless sensor networks. Theoretical analysis shows that the medium access control mechanism obviously reduces the density of infected nodes in the networks, which has been ignored in previous studies. It is also found that by increasing the network node density or node communication radius greatly increases the number of infected nodes. The theoretical results are confirmed by numerical simulations.

  4. A Stateful Multicast Access Control Mechanism for Future Metro-Area-Networks.

    ERIC Educational Resources Information Center

    Sun, Wei-qiang; Li, Jin-sheng; Hong, Pei-lin

    2003-01-01

    Multicasting is a necessity for a broadband metro-area-network; however security problems exist with current multicast protocols. A stateful multicast access control mechanism, based on MAPE, is proposed. The architecture of MAPE is discussed, as well as the states maintained and messages exchanged. The scheme is flexible and scalable. (Author/AEF)

  5. NASA Access Mechanism (NAM)

    NASA Technical Reports Server (NTRS)

    Hunter, Judy

    1993-01-01

    A 1991 user survey indicated that NASA users want (1) access to diverse sources of information; (2) an intuitive approach to system use; (3) avoidance of system query languages; (4) access to peers and other informal sources of information; and (5) simplified and enhanced presentation of search results. Based on these requirements and the use of an intelligent gateway processor, the NASA Access Mechanism (NAM) is being developed to provide the users with the semblance of a one stop shopping environment for information management.

  6. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  7. A Privacy Access Control Framework for Web Services Collaboration with Role Mechanisms

    NASA Astrophysics Data System (ADS)

    Liu, Linyuan; Huang, Zhiqiu; Zhu, Haibin

    With the popularity of Internet technology, web services are becoming the most promising paradigm for distributed computing. This increased use of web services has meant that more and more personal information of consumers is being shared with web service providers, leading to the need to guarantee the privacy of consumers. This paper proposes a role-based privacy access control framework for Web services collaboration, it utilizes roles to specify the privacy privileges of services, and considers the impact on the reputation degree of the historic experience of services in playing roles. Comparing to the traditional privacy access control approaches, this framework can make the fine-grained authorization decision, thus efficiently protecting consumers' privacy.

  8. ACCESS Pointing Control System

    NASA Technical Reports Server (NTRS)

    Brugarolas, Paul; Alexander, James; Trauger, John; Moody, Dwight; Egerman, Robert; Vallone, Phillip; Elias, Jason; Hejal, Reem; Camelo, Vanessa; Bronowicki, Allen; O'Connor, David; Partrick, Richard; Orzechowski, Pawel; Spitter, Connie; Lillie, Chuck

    2010-01-01

    ACCESS (Actively-Corrected Coronograph for Exoplanet System Studies) was one of four medium-class exoplanet concepts selected for the NASA Astrophysics Strategic Mission Concept Study (ASMCS) program in 2008/2009. The ACCESS study evaluated four major coronograph concepts under a common space observatory. This paper describes the high precision pointing control system (PCS) baselined for this observatory.

  9. CAS. Controlled Access Security

    SciTech Connect

    Martinez, B.; Pomeroy, G.

    1989-12-01

    The Security Alarm System is a data acquisition and control system which collects data from intrusion sensors and displays the information in a real-time environment for operators. The Access Control System monitors and controls the movement of personnel with the use of card readers and biometrics hand readers.

  10. Efficient Access Control in Multimedia Social Networks

    NASA Astrophysics Data System (ADS)

    Sachan, Amit; Emmanuel, Sabu

    Multimedia social networks (MMSNs) have provided a convenient way to share multimedia contents such as images, videos, blogs, etc. Contents shared by a person can be easily accessed by anybody else over the Internet. However, due to various privacy, security, and legal concerns people often want to selectively share the contents only with their friends, family, colleagues, etc. Access control mechanisms play an important role in this situation. With access control mechanisms one can decide the persons who can access a shared content and who cannot. But continuously growing content uploads and accesses, fine grained access control requirements (e.g. different access control parameters for different parts in a picture), and specific access control requirements for multimedia contents can make the time complexity of access control to be very large. So, it is important to study an efficient access control mechanism suitable for MMSNs. In this chapter we present an efficient bit-vector transform based access control mechanism for MMSNs. The proposed approach is also compatible with other requirements of MMSNs, such as access rights modification, content deletion, etc. Mathematical analysis and experimental results show the effectiveness and efficiency of our proposed approach.

  11. Speaking Two Languages for the Price of One: Bypassing Language Control Mechanisms via Accessibility-Driven Switches.

    PubMed

    Kleinman, Daniel; Gollan, Tamar H

    2016-05-01

    How do bilinguals switch easily between languages in everyday conversation, even though studies have consistently found that switching slows responses? In previous work, researchers have not considered that although switches may happen for different reasons, only some switches-including those typically studied in laboratory experiments-might be costly. Using a repeated picture-naming task, we found that bilinguals can maintain and use two languages as efficiently as a single language, switching between them frequently without any cost, if they switch only when a word is more accessible in the other language. These results suggest that language switch costs arise during lexical selection, that top-down language control mechanisms can be suspended, and that language-mixing efficiency can be strategically increased with instruction. Thus, bilinguals might switch languages spontaneously because doing so is not always costly, and there appears to be greater flexibility and efficiency in the cognitive mechanisms that enable switching than previously assumed.

  12. ADAM17 is regulated by a rapid and reversible mechanism that controls access to its catalytic site

    PubMed Central

    Le Gall, Sylvain M.; Maretzky, Thorsten; Issuree, Priya D. A.; Niu, Xiao-Da; Reiss, Karina; Saftig, Paul; Khokha, Rama; Lundell, Daniel; Blobel, Carl P.

    2010-01-01

    Protein ectodomain shedding is crucial for cell–cell interactions because it controls the bioavailability of soluble tumor necrosis factor-α (TNFα) and ligands of the epidermal growth factor (EGF) receptor, and the release of many other membrane proteins. Various stimuli can rapidly trigger ectodomain shedding, yet much remains to be learned about the identity of the enzymes that respond to these stimuli and the mechanisms underlying their activation. Here, we demonstrate that the membrane-anchored metalloproteinase ADAM17, but not ADAM10, is the sheddase that rapidly responds to the physiological signaling pathways stimulated by thrombin, EGF, lysophosphatidic acid and TNFα. Stimulation of ADAM17 is swift and quickly reversible, and does not depend on removal of its inhibitory pro-domain by pro-protein convertases, or on dissociation of an endogenous inhibitor, TIMP3. Moreover, activation of ADAM17 by physiological stimuli requires its transmembrane domain, but not its cytoplasmic domain, arguing against inside–out signaling via cytoplasmic phosphorylation as the underlying mechanism. Finally, experiments with the tight binding hydroxamate inhibitor DPC333, used here to probe the accessibility of the active site of ADAM17, demonstrate that this inhibitor can quickly bind to ADAM17 in stimulated, but not quiescent cells. These findings support the concept that activation of ADAM17 involves a rapid and reversible exposure of its catalytic site. PMID:20980382

  13. Mobile access control vestibule

    NASA Astrophysics Data System (ADS)

    DePoy, Jennifer M.

    1998-12-01

    The mobile access control vestibule (MACV) is an adaptation of techniques developed for mobile military command centers. The overall configuration of modules acts as an entry control/screening facility or transportable command center. The system would provide the following capabilities: (1) A key element for force protection, rapid deployment units sent to areas having no prepositioned equipment or where there has been a degradation of that equipment as a result of natural disasters or civil unrest. (2) A rapidly deployable security control center to upgrade the security at nonmilitary sites (e.g., diplomatic or humanitarian organizations). (3) Personnel screening, package screening, badge/identification card production for authorized personnel, centralized monitoring of deployed perimeter sensors, and centralized communications for law enforcement personnel. (4) Self-contained screening and threat detection systems, including explosives detection using the system developed by Sandia National Laboratories for the FAA. When coupled with transportable electric generators, the system is self-sufficient. The communication system for the MACV would be a combination of physically wired and wireless communication units that supports by ad hoc networking.

  14. Mechanisms that improve referential access*

    PubMed Central

    Gernsbacher, Morton Ann

    2015-01-01

    Two mechanisms, suppression and enhancement, are proposed to improve referential access. Enhancement improves the accessibility of previously mentioned concepts by increasing or boosting their activation; suppression improves concepts’ accessibility by decreasing or dampening the activation of other concepts. Presumably, these mechanisms are triggered by the informational content of anaphors. Six experiments investigated this proposal by manipulating whether an anaphoric reference was made with a very explicit, repeated name anaphor or a less explicit pronoun. Subjects read sentences that introduced two participants in their first clauses, for example, “Ann predicted that Pam would lose the track race,” and the sentences referred to one of the two participants in their second clauses, “but Pam/she came in first very easily.” While subjects read each sentence, the activation level of the two participants was measured by a probe verification task. The first two experiments demonstrated that explicit, repeated name anaphors immediately trigger the enhancement of their own antecedents and immediately trigger the suppression of other (nonantecedent) participants. The third experiment demonstrated that less explicit, pronoun anaphors also trigger the suppression of other nonantecedents, but they do so less quickly—even when, as in the fourth experiment, the semantic information to identify their antecedents occurs prior to the pronouns (e.g., “Ann predicted that Pam would lose the track race. But after winning the race, she …”). The fifth experiment demonstrated that more explicit pronouns – pronouns that match the gender of only one participant—trigger suppression more powerfully. A final experiment demonstrated that it is not only rementioned participants who improve their referential access by triggering the suppression of other participants; newly introduced participants do so too (e.g., “Ann predicted that Pam would lose the track race, but

  15. Bibliographic Access and Control System.

    ERIC Educational Resources Information Center

    Kelly, Betsy; And Others

    1982-01-01

    Presents a brief summary of the functions of the Bibliographic Access & Control System (BACS) implemented at the Washington University School of Medicine Library, and outlines the design, development, and uses of the system. Bibliographic control of books and serials and user access to the system are also discussed. (Author/JL)

  16. Speed control system for an access gate

    DOEpatents

    Bzorgi, Fariborz M [Knoxville, TN

    2012-03-20

    An access control apparatus for an access gate. The access gate typically has a rotator that is configured to rotate around a rotator axis at a first variable speed in a forward direction. The access control apparatus may include a transmission that typically has an input element that is operatively connected to the rotator. The input element is generally configured to rotate at an input speed that is proportional to the first variable speed. The transmission typically also has an output element that has an output speed that is higher than the input speed. The input element and the output element may rotate around a common transmission axis. A retardation mechanism may be employed. The retardation mechanism is typically configured to rotate around a retardation mechanism axis. Generally the retardation mechanism is operatively connected to the output element of the transmission and is configured to retard motion of the access gate in the forward direction when the first variable speed is above a control-limit speed. In many embodiments the transmission axis and the retardation mechanism axis are substantially co-axial. Some embodiments include a freewheel/catch mechanism that has an input connection that is operatively connected to the rotator. The input connection may be configured to engage an output connection when the rotator is rotated at the first variable speed in a forward direction and configured for substantially unrestricted rotation when the rotator is rotated in a reverse direction opposite the forward direction. The input element of the transmission is typically operatively connected to the output connection of the freewheel/catch mechanism.

  17. LANSCE personnel access control system

    SciTech Connect

    Sturrock, J.C.; Gallegos, F.R.; Hall, M.J.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. The Personnel Access Control System (PACS) is a component of the RSS that is designed to prevent personnel access to areas where prompt radiation is a hazard. PACS was designed to replace several older personnel safety systems (PSS) with a single modem unified design. Lessons learned from the operation over the last 20 years were incorporated into a redundant sensor, single-point failure safe, fault tolerant, and tamper-resistant system that prevents access to the beam areas by controlling the access keys and beam stoppers. PACS uses a layered philosophy to the physical and electronic design. The most critical assemblies are battery backed up, relay logic circuits; less critical devices use Programmable Logic Controllers (PLCs) for timing functions and communications. Outside reviewers have reviewed the operational safety of the design. The design philosophy, lessons learned, hardware design, software design, operation, and limitations of the device are described.

  18. Analysis of Access Control Policies in Operating Systems

    ERIC Educational Resources Information Center

    Chen, Hong

    2009-01-01

    Operating systems rely heavily on access control mechanisms to achieve security goals and defend against remote and local attacks. The complexities of modern access control mechanisms and the scale of policy configurations are often overwhelming to system administrators and software developers. Therefore, mis-configurations are common, and the…

  19. Access control and confidentiality in radiology

    NASA Astrophysics Data System (ADS)

    Noumeir, Rita; Chafik, Adil

    2005-04-01

    A medical record contains a large amount of data about the patient such as height, weight and blood pressure. It also contains sensitive information such as fertility, abortion, psychiatric data, sexually transmitted diseases and diagnostic results. Access to this information must be carefully controlled. Information technology has greatly improved patient care. The recent extensive deployment of digital medical images made diagnostic images promptly available to healthcare decision makers, regardless of their geographic location. Medical images are digitally archived, transferred on telecommunication networks, and visualized on computer screens. However, with the widespread use of computing and communication technologies in healthcare, the issue of data security has become increasingly important. Most of the work until now has focused on the security of data communication to ensure its integrity, authentication, confidentiality and user accountability. The mechanisms that have been proposed to achieve the security of data communication are not specific to healthcare. Data integrity can be achieved with data signature. Data authentication can be achieved with certificate exchange. Data confidentiality can be achieved with encryption. User accountability can be achieved with audits. Although these mechanisms are essential to ensure data security during its transfer on the network, access control is needed in order to ensure data confidentiality and privacy within the information system application. In this paper, we present and discuss an access control mechanism that takes into account the notion of a care process. Radiology information is categorized and a model to enforce data privacy is proposed.

  20. External access to ALICE controls conditions data

    NASA Astrophysics Data System (ADS)

    Jadlovský, J.; Jadlovská, A.; Sarnovský, J.; Jajčišin, Š.; Čopík, M.; Jadlovská, S.; Papcun, P.; Bielek, R.; Čerkala, J.; Kopčík, M.; Chochula, P.; Augustinus, A.

    2014-06-01

    ALICE Controls data produced by commercial SCADA system WINCCOA is stored in ORACLE database on the private experiment network. The SCADA system allows for basic access and processing of the historical data. More advanced analysis requires tools like ROOT and needs therefore a separate access method to the archives. The present scenario expects that detector experts create simple WINCCOA scripts, which retrieves and stores data in a form usable for further studies. This relatively simple procedure generates a lot of administrative overhead - users have to request the data, experts needed to run the script, the results have to be exported outside of the experiment network. The new mechanism profits from database replica, which is running on the CERN campus network. Access to this database is not restricted and there is no risk of generating a heavy load affecting the operation of the experiment. The developed tools presented in this paper allow for access to this data. The users can use web-based tools to generate the requests, consisting of the data identifiers and period of time of interest. The administrators maintain full control over the data - an authorization and authentication mechanism helps to assign privileges to selected users and restrict access to certain groups of data. Advanced caching mechanism allows the user to profit from the presence of already processed data sets. This feature significantly reduces the time required for debugging as the retrieval of raw data can last tens of minutes. A highly configurable client allows for information retrieval bypassing the interactive interface. This method is for example used by ALICE Offline to extract operational conditions after a run is completed. Last but not least, the software can be easily adopted to any underlying database structure and is therefore not limited to WINCCOA.

  1. A design of tamper resistant prescription RFID access control system.

    PubMed

    Chen, Yu-Yi; Huang, Der-Chen; Tsai, Meng-Lin; Jan, Jinn-Ke

    2012-10-01

    In this paper, we propose a tamper resistant prescription RFID access control protocol for different authorized readers. Not only the authentication mechanism but also the access right authorization mechanism is designed in our scheme. Only the specific doctor, usually the patient's doctor, can access the tag. Moreover, some related information of patient's prescription is attached to a RFID tag for tamper resistance. The patients' rights will be guaranteed.

  2. ACCESS: Thermal Mechanical Design, Performance, and Status

    NASA Astrophysics Data System (ADS)

    Kaiser, Mary Elizabeth; Morris, M. J.; McCandliss, S. R.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Bohlin, R.; Kurucz, R. L.; Riess, A. G.; Pelton, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Benford, D. J.; Gardner, J. P.; Feldman, P. D.; Moos, H. W.; Lampton, M.; Perlmutter, S.; Woodgate, B. E.

    2014-01-01

    Systematic errors associated with astrophysical data used to probe fundamental astrophysical questions, such as SNeIa observations used to constrain dark energy theories, are now rivaling and exceeding the statistical errors associated with these measurements. ACCESS: Absolute Color Calibration Experiment for Standard Stars is a series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 - 1.7μm bandpass. Achieving this level of accuracy requires characterization and stability of the instrument and detector including a thermal background that contributes less than 1% to the flux per resolution element in the NIR. We will present the instrument and calibration status with a focus on the thermal mechanical design and associated performance data. The detector control and performance will be presented in a companion poster (Morris, et al). NASA APRA sounding rocket grant NNX08AI65G supports this work.

  3. Common Badging and Access Control System (CBACS)

    NASA Technical Reports Server (NTRS)

    Dischinger, Portia

    2005-01-01

    This slide presentation presents NASA's Common Badging and Access Control System. NASA began a Smart Card implementation in January 2004. Following site surveys, it was determined that NASA's badging and access control systems required upgrades to common infrastructure in order to provide flexibly, usability, and return on investment prior to a smart card implantation. Common Badging and Access Control System (CBACS) provides the common infrastructure from which FIPS-201 compliant processes, systems, and credentials can be developed and used.

  4. 10 CFR 36.23 - Access control.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Access control. 36.23 Section 36.23 Energy NUCLEAR... activation of the control. (g) Each entrance to the radiation room of a panoramic irradiator and each... unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm must alert...

  5. 10 CFR 36.23 - Access control.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Access control. 36.23 Section 36.23 Energy NUCLEAR... activation of the control. (g) Each entrance to the radiation room of a panoramic irradiator and each... unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm must alert...

  6. 10 CFR 36.23 - Access control.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Access control. 36.23 Section 36.23 Energy NUCLEAR... activation of the control. (g) Each entrance to the radiation room of a panoramic irradiator and each... unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm must alert...

  7. 10 CFR 36.23 - Access control.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Access control. 36.23 Section 36.23 Energy NUCLEAR... activation of the control. (g) Each entrance to the radiation room of a panoramic irradiator and each... unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm must alert...

  8. 10 CFR 36.23 - Access control.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Access control. 36.23 Section 36.23 Energy NUCLEAR... activation of the control. (g) Each entrance to the radiation room of a panoramic irradiator and each... unauthorized entry when the personnel access barrier is locked. Activation of the intrusion alarm must alert...

  9. 47 CFR 95.645 - Control accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Control accessibility. 95.645 Section 95.645 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Technical Regulations Certification Requirements § 95.645 Control accessibility. (a) No...

  10. 47 CFR 95.645 - Control accessibility.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Control accessibility. 95.645 Section 95.645 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Technical Regulations Certification Requirements § 95.645 Control accessibility. (a) No...

  11. 47 CFR 95.645 - Control accessibility.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Control accessibility. 95.645 Section 95.645 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Technical Regulations Certification Requirements § 95.645 Control accessibility. (a) No...

  12. 47 CFR 95.645 - Control accessibility.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Control accessibility. 95.645 Section 95.645 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Technical Regulations Certification Requirements § 95.645 Control accessibility. (a) No...

  13. HYDRAULIC SERVO CONTROL MECHANISM

    DOEpatents

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  14. Proximity Displays for Access Control

    ERIC Educational Resources Information Center

    Vaniea, Kami

    2012-01-01

    Managing access to shared digital information, such as photographs and documents. is difficult for end users who are accumulating an increasingly large and diverse collection of data that they want to share with others. Current policy-management solutions require a user to proactively seek out and open a separate policy-management interface when…

  15. ACCESS: thermal mechanical design and performance

    NASA Astrophysics Data System (ADS)

    Kaiser, Mary E.; Morris, Matthew J.; Hansen, Jason; Jensen, Scott; McCandliss, Stephan R.; Rauscher, Bernard J.; Kimble, Randy A.; Kruk, Jeffrey W.; Pelton, Russell; Mott, D. Brent; Wen, Yiting; Gardner, Jonathan P.; Benford, Dominic J.; Woodgate, Bruce E.; Wright, Edward L.; Feldman, Paul D.; Moos, H. Warren; Riess, Adam G.; Bohlin, Ralph; Deustua, Susana E.; Dixon, W. V.; Sahnow, David J.; Kurucz, Robert; Lampton, Michael; Perlmutter, Saul

    2013-09-01

    Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant to many astrophysical problems. ACCESS, "Absolute Color Calibration Experiment for Standard Stars", is a series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35-1.7μm bandpass. Achieving a calibration accuracy of 1% not only requires an accurate calibration transfer from the detector standards to the instrument, but it also requires characterization and stability of the detector as well as a thermal background that contributes less than 1% to the flux per resolution element in the near-infrared (1.7μm) spectral region of the ACCESS bandpass. This paper describes the thermal mechanical design for achieving a low thermal background across the ACCESS spectral bandpass.

  16. Mechanism for alternating access in neurotransmitter transporters.

    PubMed

    Forrest, Lucy R; Zhang, Yuan-Wei; Jacobs, Miriam T; Gesmonde, Joan; Xie, Li; Honig, Barry H; Rudnick, Gary

    2008-07-29

    Crystal structures of LeuT, a bacterial homologue of mammalian neurotransmitter transporters, show a molecule of bound substrate that is essentially exposed to the extracellular space but occluded from the cytoplasm. Thus, there must exist an alternate conformation for LeuT in which the substrate is accessible to the cytoplasm and a corresponding mechanism that switches accessibility from one side of the membrane to the other. Here, we identify the cytoplasmic accessibility pathway of the alternate conformation in a mammalian serotonin transporter (SERT) (a member of the same transporter family as LeuT). We also propose a model for the cytoplasmic-facing state that exploits the internal pseudosymmetry observed in the crystal structure. LeuT contains two structurally similar repeats (TMs1-5 and TMs 6-10) that are inverted with respect to the plane of the membrane. The conformational differences between them result in the formation of the extracellular pathway. Our model for the cytoplasm-facing state exchanges the conformations of the two repeats and thus exposes the substrate and ion-binding sites to the cytoplasm. The conformational change that connects the two states primarily involves the tilting of a 4-helix bundle composed of transmembrane helices 1, 2, 6, and 7. Switching the tilt angle of this bundle is essentially equivalent to switching the conformation of the two repeats. Extensive mutagenesis of SERT and accessibility measurements, using cysteine reagents, are accommodated by our model. These observations may be of relevance to other transporter families, many of which contain internal inverted repeats.

  17. Context-aware access control for pervasive access to process-based healthcare systems.

    PubMed

    Koufi, Vassiliki; Vassilacopoulos, George

    2008-01-01

    Healthcare is an increasingly collaborative enterprise involving a broad range of healthcare services provided by many individuals and organizations. Grid technology has been widely recognized as a means for integrating disparate computing resources in the healthcare field. Moreover, Grid portal applications can be developed on a wireless and mobile infrastructure to execute healthcare processes which, in turn, can provide remote access to Grid database services. Such an environment provides ubiquitous and pervasive access to integrated healthcare services at the point of care, thus improving healthcare quality. In such environments, the ability to provide an effective access control mechanism that meets the requirement of the least privilege principle is essential. Adherence to the least privilege principle requires continuous adjustments of user permissions in order to adapt to the current situation. This paper presents a context-aware access control mechanism for HDGPortal, a Grid portal application which provides access to workflow-based healthcare processes using wireless Personal Digital Assistants. The proposed mechanism builds upon and enhances security mechanisms provided by the Grid Security Infrastructure. It provides tight, just-in-time permissions so that authorized users get access to specific objects according to the current context. These permissions are subject to continuous adjustments triggered by the changing context. Thus, the risk of compromising information integrity during task executions is reduced.

  18. The linked medical data access control framework.

    PubMed

    Kamateri, Eleni; Kalampokis, Evangelos; Tambouris, Efthimios; Tarabanis, Konstantinos

    2014-08-01

    The integration of medical data coming from multiple sources is important in clinical research. Amongst others, it enables the discovery of appropriate subjects in patient-oriented research and the identification of innovative results in epidemiological studies. At the same time, the integration of medical data faces significant ethical and legal challenges that impose access constraints. Some of these issues can be addressed by making available aggregated instead of raw record-level data. In many cases however, there is still a need for controlling access even to the resulting aggregated data, e.g., due to data provider's policies. In this paper we present the Linked Medical Data Access Control (LiMDAC) framework that capitalizes on Linked Data technologies to enable controlling access to medical data across distributed sources with diverse access constraints. The LiMDAC framework consists of three Linked Data models, namely the LiMDAC metadata model, the LiMDAC user profile model, and the LiMDAC access policy model. It also includes an architecture that exploits these models. Based on the framework, a proof-of-concept platform is developed and its performance and functionality are evaluated by employing two usage scenarios.

  19. NASA Access Mechanism: Lessons learned document

    NASA Technical Reports Server (NTRS)

    Burdick, Lisa; Dunbar, Rick; Duncan, Denise; Generous, Curtis; Hunter, Judy; Lycas, John; Taber-Dudas, Ardeth

    1994-01-01

    The six-month beta test of the NASA Access Mechanism (NAM) prototype was completed on June 30, 1993. This report documents the lessons learned from the use of this Graphical User Interface to NASA databases such as the NASA STI Database, outside databases, Internet resources, and peers in the NASA R&D community. Design decisions, such as the use of XWindows software, a client-server distributed architecture, and use of the NASA Science Internet, are explained. Users' reactions to the interface and suggestions for design changes are reported, as are the changes made by the software developers based on new technology for information discovery and retrieval. The lessons learned section also reports reactions from the public, both at demonstrations and in response to articles in the trade press and journals. Recommendations are included for future versions, such as a World Wide Web (WWW) and Mosaic based interface to heterogeneous databases, and NAM-Lite, a version which allows customization to include utilities provided locally at NASA Centers.

  20. Fine-Grained Access Control for Electronic Health Record Systems

    NASA Astrophysics Data System (ADS)

    Hue, Pham Thi Bach; Wohlgemuth, Sven; Echizen, Isao; Thuy, Dong Thi Bich; Thuc, Nguyen Dinh

    There needs to be a strategy for securing the privacy of patients when exchanging health records between various entities over the Internet. Despite the fact that health care providers such as Google Health and Microsoft Corp.'s Health Vault comply with the U.S Health Insurance Portability and Accountability Act (HIPAA), the privacy of patients is still at risk. Several encryption schemes and access control mechanisms have been suggested to protect the disclosure of a patient's health record especially from unauthorized entities. However, by implementing these approaches, data owners are not capable of controlling and protecting the disclosure of the individual sensitive attributes of their health records. This raises the need to adopt a secure mechanism to protect personal information against unauthorized disclosure. Therefore, we propose a new Fine-grained Access Control (FGAC) mechanism that is based on subkeys, which would allow a data owner to further control the access to his data at the column-level. We also propose a new mechanism to efficiently reduce the number of keys maintained by a data owner in cases when the users have different access privileges to different columns of the data being shared.

  1. Network Access Control List Situation Awareness

    ERIC Educational Resources Information Center

    Reifers, Andrew

    2010-01-01

    Network security is a large and complex problem being addressed by multiple communities. Nevertheless, current theories in networking security appear to overestimate network administrators' ability to understand network access control lists (NACLs), providing few context specific user analyses. Consequently, the current research generally seems to…

  2. Tethered satellite control mechanism

    NASA Technical Reports Server (NTRS)

    Kyrias, G. M.

    1983-01-01

    The tethered satellite control mechanisms consist of four major subsystems. The reel drive mechanism stores the tether. It is motor driven and includes a level wind to uniformly feed the tether to the reel. The lower boom mechanism serves two primary functions: (1) it measures tether length and velocity as the tether runs through the mechanism, and (2) it reads the tether tension at the reel. It also provides change the direction for the tether from the reel to the upper boom mechanism. The deployment boom positions the upper boom mechanism with satellite out of the cargo bay. The deployment function places the 500-kg satellite 20 m away from the Space Shuttle (producing a small natural gravity gradient force), impacts an initial velocity to the satellite for deployment, and allows for satellite docking at a safe distance from the body of the Space Shuttle. The upper boom mechanism (UBM) services three functions: (1) it provides tether control to the satellite as the satellite swings in and out of plane; (2) it reads tether tension in the low range during the early deployment and final retrieval parts of the mission; and (3) it produces additional tether tension at the reel when tether tension to the satellite is in the low range.

  3. Service Independent Access Control Architecture for User Generated Content (UGC) and Its Implementation

    NASA Astrophysics Data System (ADS)

    Yamada, Akira; Kubota, Ayumu; Miyake, Yutaka; Hashimoto, Kazuo

    Using Web-based content management systems such as Blog, an end user can easily publish User Generated Content (UGC). Although publishing of UGCs is easy, controlling access to them is a difficult problem for end users. Currently, most of Blog sites offer no access control mechanism, and even when it is available to users, it is not sufficient to control users who do not have an account at the site, not to mention that it cannot control accesses to content hosted by other UGC sites. In this paper, we propose new access control architecture for UGC, in which third party entities can offer access control mechanism to users independently of UGC hosting sites. With this architecture, a user can control accesses to his content that might be spread over many different UGC sites, regardless of whether those sites have access control mechanism or not. The key idea to separate access control mechanism from UGC sites is to apply cryptographic access control and we implemented the idea in such a way that it requires no modification to UGC sites and Web browsers. Our prototype implementation shows that the proposed access control architecture can be easily deployed in the current Web-based communication environment and it works quite well with popular Blog sites.

  4. Social Network Privacy via Evolving Access Control

    NASA Astrophysics Data System (ADS)

    di Crescenzo, Giovanni; Lipton, Richard J.

    We study the problem of limiting privacy loss due to data shared in a social network, where the basic underlying assumptions are that users are interested in sharing data and cannot be assumed to constantly follow appropriate privacy policies. Note that if these two assumptions do not hold, social network privacy is theoretically very easy to achieve; for instance, via some form of access control and confidentiality transformation on the data.

  5. Common Badging and Access Control System (CBACS)

    NASA Technical Reports Server (NTRS)

    Baldridge, Tim

    2005-01-01

    The goals of the project are: Achieve high business value through a common badging and access control system that integrates with smart cards. Provide physical (versus logical) deployment of smart cards initially. Provides a common consistent and reliable environment into which to release the smart card. Gives opportunity to develop agency-wide consistent processes, practices and policies. Enables enterprise data capture and management. Promotes data validation prior to SC issuance.

  6. REACTOR CONTROL MECHANISM

    DOEpatents

    Lane, J.A.; Engberg, R.E.; Welch, J.M.

    1959-05-12

    A quick-releasing mechanism is described which may be used to rapidiy drop a device supported from beneath during normal use, such as a safety rod in a nuclear reactor. In accordance with this invention an electrical control signal, such as may be provided by radiation detection or other alarm condition sensing devices, is delivered to an electromagnetic solenoid, the armature of which is coupled to an actuating mechanism. The solenoid is energized when the mechanism is in its upper or cocked position. In such position, the mechanism engages a plurality of retaining balls, forcing them outward into engagement with a shoulder or recess in a corresponding section of a tubular extension on the upheld device. When the control signal to the solenoid suddenly ceases, the armature drops out, allowing the actuating mechanism to move slightly but rapidly under the force of a compressed spring. The weight of the device will urge the balls inward against a beveled portion of the actuating mechanism and away from the engaging section on the tubular extension, thus allowing the upheld device to fall freely under the influence of gravity.

  7. A service-oriented data access control model

    NASA Astrophysics Data System (ADS)

    Meng, Wei; Li, Fengmin; Pan, Juchen; Song, Song; Bian, Jiali

    2017-01-01

    The development of mobile computing, cloud computing and distributed computing meets the growing individual service needs. Facing with complex application system, it's an urgent problem to ensure real-time, dynamic, and fine-grained data access control. By analyzing common data access control models, on the basis of mandatory access control model, the paper proposes a service-oriented access control model. By regarding system services as subject and data of databases as object, the model defines access levels and access identification of subject and object, and ensures system services securely to access databases.

  8. Cardea: Dynamic Access Control in Distributed Systems

    NASA Technical Reports Server (NTRS)

    Lepro, Rebekah

    2004-01-01

    Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework. First, the authorization model employed in Cardea and its functionality goals are examined. Next, critical features of the system architecture and its handling of the authorization process are then examined. Then the S A M L and XACML standards, as incorporated into the system, are analyzed. Finally, the future directions of this project are outlined and connection points with general components of an authorization system are highlighted.

  9. Application-Defined Decentralized Access Control

    PubMed Central

    Xu, Yuanzhong; Dunn, Alan M.; Hofmann, Owen S.; Lee, Michael Z.; Mehdi, Syed Akbar; Witchel, Emmett

    2014-01-01

    DCAC is a practical OS-level access control system that supports application-defined principals. It allows normal users to perform administrative operations within their privilege, enabling isolation and privilege separation for applications. It does not require centralized policy specification or management, giving applications freedom to manage their principals while the policies are still enforced by the OS. DCAC uses hierarchically-named attributes as a generic framework for user-defined policies such as groups defined by normal users. For both local and networked file systems, its execution time overhead is between 0%–9% on file system microbenchmarks, and under 1% on applications. This paper shows the design and implementation of DCAC, as well as several real-world use cases, including sandboxing applications, enforcing server applications’ security policies, supporting NFS, and authenticating user-defined sub-principals in SSH, all with minimal code changes. PMID:25426493

  10. Modeling mandatory access control in role-based security systems

    SciTech Connect

    Nyanchama, M.; Osborn, S.

    1996-12-31

    This paper discusses the realization of mandatory access control in role-based protection systems. Starting from the basic definitions of roles, their application in security and the basics of the concept of mandatory access control, we develop a scheme of role-based protection that realizes mandatory access control. The basis of this formulation develops from the recognition that roles can be seen as facilitating access to some given information context. By handling each of the role contexts as independent security levels of information, we simulate mandatory access by imposing the requirements of mandatory access control. Among the key considerations, we propose a means of taming Trojan horses by imposing acyclic information flow among contexts in role-based protection systems. The acyclic information flows and suitable access rules incorporate secrecy which is an essential component of mandatory access control.

  11. Gear shift control mechanism

    SciTech Connect

    Janson, D.A.

    1987-03-10

    A gear shift control mechanism is described comprising: multiple shift rods directed substantially parallel to one another, each rod carrying a shift fork for axial movement; a shift lever supported for pivotal movement about a first axis directed parallel to the axes of the shift rods and for pivotal movement about a second axis directed substantially perpendicular to the axes of the shift rods. The lever is moveable about the first axis and the second axis into engagement with a selected shift fork; interlock means located on each lateral side of the shift lever and mounted for pivotal movement about the first axis for blocking engagement with the shift forks; detent means for holding the shift lever in multiple predetermined angular positions about the second axis; and spring means located on a lateral side of the shift lever and mounted for pivotal movement about the first axis into interference contact with the shift forks for producing a force tending to resiliently bias the shift lever out of engagement with the selected shift fork.

  12. Access Control Model for Sharing Composite Electronic Health Records

    NASA Astrophysics Data System (ADS)

    Jin, Jing; Ahn, Gail-Joon; Covington, Michael J.; Zhang, Xinwen

    The adoption of electronically formatted medical records, so called Electronic Health Records (EHRs), has become extremely important in healthcare systems to enable the exchange of medical information among stakeholders. An EHR generally consists of data with different types and sensitivity degrees which must be selectively shared based on the need-to-know principle. Security mechanisms are required to guarantee that only authorized users have access to specific portions of such critical record for legitimate purposes. In this paper, we propose a novel approach for modelling access control scheme for composite EHRs. Our model formulates the semantics and structural composition of an EHR document, from which we introduce a notion of authorized zones of the composite EHR at different granularity levels, taking into consideration of several important criteria such as data types, intended purposes and information sensitivities.

  13. The molecular mechanisms of hemodialysis vascular access failure

    PubMed Central

    Franzoni, Marco; Misra, Sanjay

    2016-01-01

    The arteriovenous fistula has been used for more than 50 years to provide vascular access for patients undergoing hemodialysis. More than 1.5 million patients worldwide have end stage renal disease and this population will continue to grow. The arteriovenous fistula is the preferred vascular access for patients, but its patency rate at 1 year is only 60%. The majority of arteriovenous fistulas fail because of intimal hyperplasia. In recent years, there have been many studies investigating the molecular mechanisms responsible for intimal hyperplasia and subsequent thrombosis. These studies have identified common pathways including inflammation, uremia, hypoxia, sheer stress, and increased thrombogenicity. These cellular mechanisms lead to increased proliferation, migration, and eventually stenosis. These pathways work synergistically through shared molecular messengers. In this review, we will examine the literature concerning the molecular basis of hemodialysis vascular access malfunction. PMID:26806833

  14. Two Mechanisms to Avoid Control Conflicts Resulting from Uncoordinated Intent

    NASA Technical Reports Server (NTRS)

    Mishkin, Andrew H.; Dvorak, Daniel L.; Wagner, David A.; Bennett, Matthew B.

    2013-01-01

    This software implements a real-time access control protocol that is intended to make all connected users aware of the presence of other connected users, and which of them is currently in control of the system. Here, "in control" means that a single user is authorized and enabled to issue instructions to the system. The software The software also implements a goal scheduling mechanism that can detect situations where plans for the operation of a target system proposed by different users overlap and interact in conflicting ways. In such situations, the system can either simply report the conflict (rejecting one goal or the entire plan), or reschedule the goals in a way that does not conflict. The access control mechanism (and associated control protocol) is unique. Other access control mechanisms are generally intended to authenticate users, or exclude unauthorized access. This software does neither, and would likely depend on having some other mechanism to support those requirements.

  15. 33 CFR 106.260 - Security measures for access control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf (OCS) Facility Security Requirements § 106.260 Security measures for access control. (a)...

  16. 33 CFR 106.260 - Security measures for access control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf (OCS) Facility Security Requirements § 106.260 Security measures for access control. (a)...

  17. 33 CFR 106.260 - Security measures for access control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES Outer Continental Shelf (OCS) Facility Security Requirements § 106.260 Security measures for access control. (a)...

  18. Open versus Controlled-Access Data | Office of Cancer Genomics

    Cancer.gov

    OCG employs stringent human subjects’ protection and data access policies to protect the privacy and confidentiality of the research participants. Depending on the risk of patient identification, OCG programs data are available to the scientific community in two tiers: open or controlled access. Both types of data can be accessed through its corresponding OCG program-specific data matrix or portal. Open-access Data

  19. NASA Access Mechanism - Graphical user interface information retrieval system

    NASA Technical Reports Server (NTRS)

    Hunter, Judy F.; Generous, Curtis; Duncan, Denise

    1993-01-01

    Access to online information sources of aerospace, scientific, and engineering data, a mission focus for NASA's Scientific and Technical Information Program, has always been limited by factors such as telecommunications, query language syntax, lack of standardization in the information, and the lack of adequate tools to assist in searching. Today, the NASA STI Program's NASA Access Mechanism (NAM) prototype offers a solution to these problems by providing the user with a set of tools that provide a graphical interface to remote, heterogeneous, and distributed information in a manner adaptable to both casual and expert users. Additionally, the NAM provides access to many Internet-based services such as Electronic Mail, the Wide Area Information Servers system, Peer Locating tools, and electronic bulletin boards.

  20. NASA access mechanism: Graphical user interface information retrieval system

    NASA Technical Reports Server (NTRS)

    Hunter, Judy; Generous, Curtis; Duncan, Denise

    1993-01-01

    Access to online information sources of aerospace, scientific, and engineering data, a mission focus for NASA's Scientific and Technical Information Program, has always been limited to factors such as telecommunications, query language syntax, lack of standardization in the information, and the lack of adequate tools to assist in searching. Today, the NASA STI Program's NASA Access Mechanism (NAM) prototype offers a solution to these problems by providing the user with a set of tools that provide a graphical interface to remote, heterogeneous, and distributed information in a manner adaptable to both casual and expert users. Additionally, the NAM provides access to many Internet-based services such as Electronic Mail, the Wide Area Information Servers system, Peer Locating tools, and electronic bulletin boards.

  1. Permission to Speak: A Novel Formal Foundation for Access Control

    DTIC Science & Technology

    2016-06-21

    NAME(S) AND ADDRESS(ES) University of Pennsylvania,Computer and Information Science ,Philadelphia,PA,19104 8. PERFORMING ORGANIZATION REPORT NUMBER... science • Uniform treatment of access control and conformance – Access control is verification of permissions – Conformance is satisfaction of

  2. 33 CFR 105.255 - Security measures for access control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... each MARSEC Level, including those points where TWIC access control provisions will be applied. Each... escorting them; (4) Procedures for identifying authorized and unauthorized persons at any MARSEC level; and... access controls, particularly if they are to be applied on a random or occasional basis. (f) MARSEC...

  3. Controlled mechanized trepan.

    PubMed

    Kam, J; Goldratt, E M; Barishak, Y R; Stein, R

    1978-04-01

    A mechanized trepan is described whose cutting action is halted automatically when the trepan's cutting edge reaches the last 0.03 mm. tissue layer of the cornea. The automatic half of both the motor which advances the trepan as well as the second motor which rotates the trepan is triggered by the sudden change in electrical resistance between the trepan and the patient's internal body fluid, at the final stage of penetration. This automatic feature eliminates the danger of inadvertant damage to the inner structures of the eye.

  4. Managed Access by Controlled Sensing (MACS)

    SciTech Connect

    Curtiss, J.A.; Indusi, J.P.

    1994-08-01

    During chemical weapons challenge inspections, the CWC treaty allows ``alternate means`` of access to be proposed by the nation challenged. BNL`s Safeguards, Safety and Nonproliferation Division is funded by the Defense Nuclear Agency to develop a system to provide the challenge inspection team with a ``virtual presence`` within the facility while denying personal access. A general purpose configuration of a mobile station manned by site personnel and a base station manned by the challenge inspector, supported by a flexible communication system, will allow facility personnel to tailor the basic model to their site. Design of the MACS system is based on maximum use of commercial equipment that is available on the international market. Design requirements for the MACS system include methods of establishing geographical position, distance measuring equipment for use in verifying dimensions on floor plans, video and two-way audio links between the mobile unit and the base station, and portability and versatility of the equipment. The MACS platform will also support deployment of selected instrumentation which the site may offer to the challenge inspection team. This paper describes the design and construction of the prototype MACS system.

  5. 49 CFR 1542.207 - Access control systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Access control systems. 1542.207 Section 1542.207 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRPORT SECURITY Operations § 1542.207 Access...

  6. 49 CFR 1542.207 - Access control systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Access control systems. 1542.207 Section 1542.207 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRPORT SECURITY Operations § 1542.207 Access...

  7. 49 CFR 1542.207 - Access control systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Access control systems. 1542.207 Section 1542.207 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRPORT SECURITY Operations § 1542.207 Access...

  8. 49 CFR 1542.207 - Access control systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Access control systems. 1542.207 Section 1542.207 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRPORT SECURITY Operations § 1542.207 Access...

  9. 49 CFR 1542.207 - Access control systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Access control systems. 1542.207 Section 1542.207 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY AIRPORT SECURITY Operations § 1542.207 Access...

  10. Urban Studies: A Study of Bibliographic Access and Control.

    ERIC Educational Resources Information Center

    Anderson, Barbara E.

    This paper analyzes: (1) the bibliographic access to publications in urban studies via printed secondary sources; (2) development and scope of classification systems and of vocabulary control for urban studies; and (3) currently accessible automated collections of bibliographic citations. Urban studies is defined as "an agglomeration of…

  11. 14 CFR 420.53 - Control of public access.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Responsibilities of a Licensee § 420.53 Control of public access. (a) A licensee shall prevent unauthorized access to the launch site, and... the launch site of safety rules and emergency and evacuation procedures prior to that person's...

  12. First Experiences Using XACML for Access Control in Distributed Systems

    NASA Technical Reports Server (NTRS)

    Lorch, Marcus; Proctor, Seth; Lepro, Rebekah; Kafura, Dennis; Shah, Sumit

    2003-01-01

    Authorization systems today are increasingly complex. They span domains of administration, rely on many different authentication sources, and manage permissions that can be as complex as the system itself. Worse still, while there are many standards that define authentication mechanisms, the standards that address authorization are less well defined and tend to work only within homogeneous systems. This paper presents XACML, a standard access control language, as one component of a distributed and inter-operable authorization framework. Several emerging systems which incorporate XACML are discussed. These discussions illustrate how authorization can be deployed in distributed, decentralized systems. Finally, some new and future topics are presented to show where this work is heading and how it will help connect the general components of an authorization system.

  13. Access Control of Web- and Java-Based Applications

    NASA Technical Reports Server (NTRS)

    Tso, Kam S.; Pajevski, Michael J.

    2013-01-01

    Cybersecurity has become a great concern as threats of service interruption, unauthorized access, stealing and altering of information, and spreading of viruses have become more prevalent and serious. Application layer access control of applications is a critical component in the overall security solution that also includes encryption, firewalls, virtual private networks, antivirus, and intrusion detection. An access control solution, based on an open-source access manager augmented with custom software components, was developed to provide protection to both Web-based and Javabased client and server applications. The DISA Security Service (DISA-SS) provides common access control capabilities for AMMOS software applications through a set of application programming interfaces (APIs) and network- accessible security services for authentication, single sign-on, authorization checking, and authorization policy management. The OpenAM access management technology designed for Web applications can be extended to meet the needs of Java thick clients and stand alone servers that are commonly used in the JPL AMMOS environment. The DISA-SS reusable components have greatly reduced the effort for each AMMOS subsystem to develop its own access control strategy. The novelty of this work is that it leverages an open-source access management product that was designed for Webbased applications to provide access control for Java thick clients and Java standalone servers. Thick clients and standalone servers are still commonly used in businesses and government, especially for applications that require rich graphical user interfaces and high-performance visualization that cannot be met by thin clients running on Web browsers

  14. Personnel Access Control System Evaluation for National Ignition Facility Operations

    SciTech Connect

    Altenbach, T; Brereton, S.; Hermes, G.; Singh, M.

    2001-06-01

    The purpose of this document is to analyze the baseline Access Control System for the National Ignition Facility (NIF), and to assess its effectiveness at controlling access to hazardous locations during full NIF operations. It reviews the various hazards present during a NIF shot sequence, and evaluates the effectiveness of the applicable set of controls at preventing access while the hazards are present. It considers only those hazards that could potentially be lethal. In addition, various types of technologies that might be applicable at NIF are reviewed, as are systems currently in use at other facilities requiring access control for safety reasons. Recommendations on how this system might be modified to reduce risk are made.

  15. Mining Roles and Access Control for Relational Data under Privacy and Accuracy Constraints

    ERIC Educational Resources Information Center

    Pervaiz, Zahid

    2013-01-01

    Access control mechanisms protect sensitive information from unauthorized users. However, when sensitive information is shared and a Privacy Protection Mechanism (PPM) is not in place, an authorized insider can still compromise the privacy of a person leading to identity disclosure. A PPM can use suppression and generalization to anonymize and…

  16. Authenticated IGMP for Controlling Access to Multicast Distribution Tree

    NASA Astrophysics Data System (ADS)

    Park, Chang-Seop; Kang, Hyun-Sun

    A receiver access control scheme is proposed to protect the multicast distribution tree from DoS attack induced by unauthorized use of IGMP, by extending the security-related functionality of IGMP. Based on a specific network and business model adopted for commercial deployment of IP multicast applications, a key management scheme is also presented for bootstrapping the proposed access control as well as accounting and billing for CP (Content Provider), NSP (Network Service Provider), and group members.

  17. Brain Mechanisms of Attentional Control.

    ERIC Educational Resources Information Center

    Wilke, Thomas

    Lack of attentional control--inability to concentrate--has often made the difference between successful and unsuccessful performance on the part of athletes. Attention is controlled neurologically by a very complex interaction of a large portion of the cerebrum and is not localized to any one structure. The mechanism involves a memory retrieval…

  18. RANDOM ACCESS CONTROL OF ELECTROLUMINESCENT ELEMENTS.

    DTIC Science & Technology

    Cadmium selenide (CdSe) switches were devised to control the luminous emittance of electroluminescent cells in a solid-state display. The technique...purpose of this contract was to establish the feasibility of utilizing the hysteretic effect in cadmium selenide to provide switching and storage to an...array of electroluminescent cells by investigating the cadmium selenide material, by studying panel structure, and by investigating the addressing of

  19. Control Processes and Defense Mechanisms

    PubMed Central

    HOROWITZ, MARDI; COOPER, STEVEN; FRIDHANDLER, BRAM; PERRY, J. CHRISTOPHER; BOND, MICHAEL; VAILLANT, GEORGE

    1992-01-01

    Defense-mechanism theory and control-process theory are related psychodynamic approaches to explaining and classifying how people ward off emotional upsets. Although both theories explain defensive maneuvers in the same motivational terms, each defines categories different1y. Classic categories define defense mechanisms at a relatively macroscopic level, whereas control-process theory aims at relatively microgenetic analysis of how cognitive maneuvers—involving what is thought, how it is thought, and how it is organized—may generate defensive states. The theories are not contradictory, but they are focused on different levels of observation; it is useful to compare how these classifications are applied to specific case material. PMID:22700114

  20. Control with a random access protocol and packet dropouts

    NASA Astrophysics Data System (ADS)

    Wang, Liyuan; Guo, Ge

    2016-08-01

    This paper investigates networked control systems whose actuators communicate with the controller via a limited number of unreliable channels. The access to the channels is decided by a so-called group random access protocol, which is modelled as a binary Markov sequence. Data packet dropouts in the channels are modelled as independent Bernoulli processes. For such systems, a systematic characterisation for controller synthesis is established and stated in terms of the transition probabilities of the Markov protocol and the packet dropout probabilities. The results are illustrated via a numerical example.

  1. Towards an Access-Control Framework for Countering Insider Threats

    NASA Astrophysics Data System (ADS)

    Crampton, Jason; Huth, Michael

    As insider threats pose very significant security risks to IT systems, we ask what policy-based approaches to access control can do for the detection, mitigation or countering of insider threats and insider attacks. Answering this question is difficult: little public data about insider-threat cases is available; there is not much consensus about what the insider problem actually is; and previous research in access control has by-and-large not dealt with this issue. We explore existing notions of insiderness in order to identify the relevant research issues. We then formulate a set of requirements for next-generation access-control systems, whose realization might form part of an overall strategy to address the insider problem.

  2. Steganography-based access control to medical data hidden in electrocardiogram.

    PubMed

    Mai, Vu; Khalil, Ibrahim; Ibaida, Ayman

    2013-01-01

    Steganographic techniques allow secret data to be embedded inside another host data such as an image or a text file without significant changes to the quality of the host data. In this research, we demonstrate how steganography can be used as the main mechanism to build an access control model that gives data owners complete control to their sensitive cardiac health information hidden in their own Electrocardiograms. Our access control model is able to protect the privacy of users, the confidentiality of medical data, reduce storage space and make it more efficient to upload and download large amount of data.

  3. Universal Controller for Spacecraft Mechanisms

    NASA Technical Reports Server (NTRS)

    Levanas, Greg; McCarthy, Thomas; Hunter, Don; Buchanan, Christine; Johnson, Michael; Cozy, Raymond; Morgan, Albert; Tran, Hung

    2006-01-01

    An electronic control unit has been fabricated and tested that can be replicated as a universal interface between the electronic infrastructure of a spacecraft and a brushless-motor (or other electromechanical actuator) driven mechanism that performs a specific mechanical function within the overall spacecraft system. The unit includes interfaces to a variety of spacecraft sensors, power outputs, and has selectable actuator control parameters making the assembly a mechanism controller. Several control topologies are selectable and reconfigurable at any time. This allows the same actuator to perform different functions during the mission life of the spacecraft. The unit includes complementary metal oxide/semiconductor electronic components on a circuit board of a type called rigid flex (signifying flexible printed wiring along with a rigid substrate). The rigid flex board is folded to make the unit fit into a housing on the back of a motor. The assembly has redundant critical interfaces, allowing the controller to perform time-critical operations when no human interface with the hardware is possible. The controller is designed to function over a wide temperature range without the need for thermal control, including withstanding significant thermal cycling, making it usable in nearly all environments that spacecraft or landers will endure. A prototype has withstood 1,500 thermal cycles between 120 and +85 C without significant deterioration of its packaging or electronic function. Because there is no need for thermal control and the unit is addressed through a serial bus interface, the cabling and other system hardware are substantially reduced in quantity and complexity, with corresponding reductions in overall spacecraft mass and cost.

  4. Controlling user access to electronic resources without password

    DOEpatents

    Smith, Fred Hewitt

    2015-06-16

    Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes pre-determining an association of the restricted computer resource and computer-resource-proximal environmental information. Indicia of user-proximal environmental information are received from a user requesting access to the restricted computer resource. Received indicia of user-proximal environmental information are compared to associated computer-resource-proximal environmental information. User access to the restricted computer resource is selectively granted responsive to a favorable comparison in which the user-proximal environmental information is sufficiently similar to the computer-resource proximal environmental information. In at least some embodiments, the process further includes comparing user-supplied biometric measure and comparing it with a predetermined association of at least one biometric measure of an authorized user. Access to the restricted computer resource is granted in response to a favorable comparison.

  5. Secondary retention of rubber dam: effective moisture control access considerations.

    PubMed

    Liebenberg, W H

    1995-04-01

    Primary rubber dam retention affects attachment of the latex sheet to the anchor teeth bordering the isolated working field. Secondary rubber dam retention is the provision of an effective seal at the dam-tooth junction, which is essential to the maintenance of adequate access and moisture control within the working field. Practical hints are offered to optimize access and moisture control through well-planned and properly executed secondary retention of classic rubber dam applications. In addition, innovative solutions to the limitations of general field isolation, which pertain mostly to secondary retention of the unrestrained buccal and lingual curtains of the slit dam, are introduced.

  6. Access and control of information and intellectual property

    NASA Astrophysics Data System (ADS)

    Lang, Gerald S.

    1996-03-01

    This paper introduces the technology of two pioneering patents for the secure distribution of information and intellectual property. The seminal technology has been used in the control of sensitive material such as medical records and imagery in distributed networks. It lends itself to the implementation of an open architecture access control system that provides local or remote user selective access to digital information stored on any computer system or storage medium, down to the data element, pixel, and sub-pixel levels. Use of this technology is especially suited for electronic publishing, health care records, MIS, and auditing.

  7. Mechanical control of electroresistive switching

    SciTech Connect

    Kim, Yunseok; Kelly, Simon J; Strelcov, Evgheni; Jesse, Stephen; Biegalski, Michael D; Balke, Nina; Maksymovych, Petro; Kalinin, Sergei V

    2013-01-01

    Hysteretic metal-insulator transitions (MIT) mediated by ionic dynamics or ferroic phase transitions underpin emergent applications for non-volatile memories and logic devices. The vast majority of applications and studies have explored the MIT coupled to the electric field or temperarture. Here, we argue that MIT coupled to ionic dynamics should allow control by mechanical stimuli, the behavior we refer to as piezochemical effect. We verify this effect experimentally, and demonstrate that it allows both studying materials physics and enabling novel data storage technologies with mechanical writing and current based read-out.

  8. Joint Access Control Based on Access Ratio and Resource Utilization for High-Speed Railway Communications

    NASA Astrophysics Data System (ADS)

    Zhou, Yuzhe; Ai, Bo

    2015-05-01

    The fast development of high-speed rails makes people's life more and more convenient. However, provisioning of quality of service of multimedia applications for users on the high-speed train is a critical task for wireless communications. Therefore, new solutions are desirable to be found to address this kind of problem. Current researches mainly focus on providing seamless broadband wireless access for high-speed mobile terminals. In this paper, an algorithm to calculate the optimal resource reservation fraction of handovers is proposed. A joint access control scheme for high-speed railway communication handover scenario is proposed. Metrics of access ratio and resource utilization ratio are considered jointly in the analysis and the performance evaluation. Simulation results show that the proposed algorithm and the scheme improve quality of service compared with other conventional schemes.

  9. Access Control of Web and Java Based Applications

    NASA Technical Reports Server (NTRS)

    Tso, Kam S.; Pajevski, Michael J.; Johnson, Bryan

    2011-01-01

    Cyber security has gained national and international attention as a result of near continuous headlines from financial institutions, retail stores, government offices and universities reporting compromised systems and stolen data. Concerns continue to rise as threats of service interruption, and spreading of viruses become ever more prevalent and serious. Controlling access to application layer resources is a critical component in a layered security solution that includes encryption, firewalls, virtual private networks, antivirus, and intrusion detection. In this paper we discuss the development of an application-level access control solution, based on an open-source access manager augmented with custom software components, to provide protection to both Web-based and Java-based client and server applications.

  10. Turbomachinery Fluid Mechanics and Control

    DTIC Science & Technology

    2010-01-01

    side, thereby limiting the achievable flow. Further numerical studies were completed to improve the flow field performance in the internal passages...Shear Layers”, Journal of Fluid Mechanics , 1996, 308: 63-96 7. M. R. Van der Veer and P. J. Strykowski, “Counterflow Thrust Vector Control of...particularly for highly loaded blade rows, can be very complex and requires systematic study . In the work described here, experimental

  11. Access Control for Agent-based Computing: A Distributed Approach.

    ERIC Educational Resources Information Center

    Antonopoulos, Nick; Koukoumpetsos, Kyriakos; Shafarenko, Alex

    2001-01-01

    Discusses the mobile software agent paradigm that provides a foundation for the development of high performance distributed applications and presents a simple, distributed access control architecture based on the concept of distributed, active authorization entities (lock cells), any combination of which can be referenced by an agent to provide…

  12. Secure Dynamic access control scheme of PHR in cloud computing.

    PubMed

    Chen, Tzer-Shyong; Liu, Chia-Hui; Chen, Tzer-Long; Chen, Chin-Sheng; Bau, Jian-Guo; Lin, Tzu-Ching

    2012-12-01

    With the development of information technology and medical technology, medical information has been developed from traditional paper records into electronic medical records, which have now been widely applied. The new-style medical information exchange system "personal health records (PHR)" is gradually developed. PHR is a kind of health records maintained and recorded by individuals. An ideal personal health record could integrate personal medical information from different sources and provide complete and correct personal health and medical summary through the Internet or portable media under the requirements of security and privacy. A lot of personal health records are being utilized. The patient-centered PHR information exchange system allows the public autonomously maintain and manage personal health records. Such management is convenient for storing, accessing, and sharing personal medical records. With the emergence of Cloud computing, PHR service has been transferred to storing data into Cloud servers that the resources could be flexibly utilized and the operation cost can be reduced. Nevertheless, patients would face privacy problem when storing PHR data into Cloud. Besides, it requires a secure protection scheme to encrypt the medical records of each patient for storing PHR into Cloud server. In the encryption process, it would be a challenge to achieve accurately accessing to medical records and corresponding to flexibility and efficiency. A new PHR access control scheme under Cloud computing environments is proposed in this study. With Lagrange interpolation polynomial to establish a secure and effective PHR information access scheme, it allows to accurately access to PHR with security and is suitable for enormous multi-users. Moreover, this scheme also dynamically supports multi-users in Cloud computing environments with personal privacy and offers legal authorities to access to PHR. From security and effectiveness analyses, the proposed PHR access

  13. Access control and interlock system at the Advanced Photon Source

    SciTech Connect

    Forrestal, J.; Hogrefe, R.; Knott, M.; McDowell, W.; Reigle, D.; Solita, L.; Koldenhoven, R.; Haid, D.

    1997-08-01

    The Advanced Photon Source (APS) consists of a linac, position accumulator ring (PAR), booster synchrotron, storage ring, and up to 70 experimental beamlines. The Access Control and Interlock System (ACIS) utilizes redundant programmable logic controllers (PLCs) and a third hard-wired chain to protect personnel from prompt radiation generated by the linac, PAR, synchrotron, and storage ring. This paper describes the ACIS`s design philosophy, configuration, hardware, functionality, validation requirements, and operational experience.

  14. Immune mechanisms of HIV control

    PubMed Central

    Chakrabarti, Lisa A.; Simon, Viviana

    2010-01-01

    Summary HIV-1 can be contained by the immune system, as demonstrated by the existence of rare individuals who spontaneously control HIV-1 replication in the absence of antiretroviral therapy. Emerging evidence points to the importance of a very active cellular immune response in mediating HIV-1 control. The rapid induction of interferon-dependent HIV restriction factors, the presence of protective MHC class I alleles, and the development of a high avidity T-cell response may all cooperate in limiting HIV replication at an early stage. This review will focus on recent advances in understanding the immune mechanisms of HIV control, and on the lessons that may be drawn for the development of candidate HIV vaccines. PMID:20650621

  15. LTE-advanced random access mechanism for M2M communication: A review

    NASA Astrophysics Data System (ADS)

    Mustafa, Rashid; Sarowa, Sandeep; Jaglan, Reena Rathee; Khan, Mohammad Junaid; Agrawal, Sunil

    2016-03-01

    Machine Type Communications (MTC) enables one or more self-sufficient machines to communicate directly with one another without human interference. MTC applications include smart grid, security, e-Health and intelligent automation system. To support huge numbers of MTC devices, one of the challenging issues is to provide a competent way for numerous access in the network and to minimize network overload. In this article, the different control mechanisms for overload random access are reviewed to avoid congestion caused by random access channel (RACH) of MTC devices. However, past and present wireless technologies have been engineered for Human-to-Human (H2H) communications, in particular, for transmission of voice. Consequently the Long Term Evolution (LTE) -Advanced is expected to play a central role in communicating Machine to Machine (M2M) and are very optimistic about H2H communications. Distinct and unique characteristics of M2M communications create new challenges from those in H2H communications. In this article, we investigate the impact of massive M2M terminals attempting random access to LTE-Advanced all at once. We discuss and review the solutions to alleviate the overload problem by Third Generation Partnership Project (3GPP). As a result, we evaluate and compare these solutions that can effectively eliminate the congestion on the random access channel for M2M communications without affecting H2H communications.

  16. Regulation of the nucleosome unwrapping rate controls DNA accessibility

    PubMed Central

    North, Justin A.; Shimko, John C.; Javaid, Sarah; Mooney, Alex M.; Shoffner, Matthew A.; Rose, Sean D.; Bundschuh, Ralf; Fishel, Richard; Ottesen, Jennifer J.; Poirier, Michael G.

    2012-01-01

    Eukaryotic genomes are repetitively wrapped into nucleosomes that then regulate access of transcription and DNA repair complexes to DNA. The mechanisms that regulate extrinsic protein interactions within nucleosomes are unresolved. We demonstrate that modulation of the nucleosome unwrapping rate regulates protein binding within nucleosomes. Histone H3 acetyl-lysine 56 [H3(K56ac)] and DNA sequence within the nucleosome entry-exit region additively influence nucleosomal DNA accessibility by increasing the unwrapping rate without impacting rewrapping. These combined epigenetic and genetic factors influence transcription factor (TF) occupancy within the nucleosome by at least one order of magnitude and enhance nucleosome disassembly by the DNA mismatch repair complex, hMSH2–hMSH6. Our results combined with the observation that ∼30% of Saccharomyces cerevisiae TF-binding sites reside in the nucleosome entry–exit region suggest that modulation of nucleosome unwrapping is a mechanism for regulating transcription and DNA repair. PMID:22965129

  17. Distributed reservation control protocols for random access broadcasting channels

    NASA Astrophysics Data System (ADS)

    Greene, E. P.; Ephremides, A.

    1981-05-01

    Attention is given to a communication network consisting of an arbitrary number of nodes which can communicate with each other via a time-division multiple access (TDMA) broadcast channel. The reported investigation is concerned with the development of efficient distributed multiple access protocols for traffic consisting primarily of single packet messages in a datagram mode of operation. The motivation for the design of the protocols came from the consideration of efficient multiple access utilization of moderate to high bandwidth (4-40 Mbit/s capacity) communication satellite channels used for the transmission of short (1000-10,000 bits) fixed length packets. Under these circumstances, the ratio of roundtrip propagation time to packet transmission time is between 100 to 10,000. It is shown how a TDMA channel can be adaptively shared by datagram traffic and constant bandwidth users such as in digital voice applications. The distributed reservation control protocols described are a hybrid between contention and reservation protocols.

  18. Distributed reservation control protocols for random access broadcasting channels

    NASA Technical Reports Server (NTRS)

    Greene, E. P.; Ephremides, A.

    1981-01-01

    Attention is given to a communication network consisting of an arbitrary number of nodes which can communicate with each other via a time-division multiple access (TDMA) broadcast channel. The reported investigation is concerned with the development of efficient distributed multiple access protocols for traffic consisting primarily of single packet messages in a datagram mode of operation. The motivation for the design of the protocols came from the consideration of efficient multiple access utilization of moderate to high bandwidth (4-40 Mbit/s capacity) communication satellite channels used for the transmission of short (1000-10,000 bits) fixed length packets. Under these circumstances, the ratio of roundtrip propagation time to packet transmission time is between 100 to 10,000. It is shown how a TDMA channel can be adaptively shared by datagram traffic and constant bandwidth users such as in digital voice applications. The distributed reservation control protocols described are a hybrid between contention and reservation protocols.

  19. Access control and privacy in large distributed systems

    NASA Technical Reports Server (NTRS)

    Leiner, B. M.; Bishop, M.

    1986-01-01

    Large scale distributed systems consists of workstations, mainframe computers, supercomputers and other types of servers, all connected by a computer network. These systems are being used in a variety of applications including the support of collaborative scientific research. In such an environment, issues of access control and privacy arise. Access control is required for several reasons, including the protection of sensitive resources and cost control. Privacy is also required for similar reasons, including the protection of a researcher's proprietary results. A possible architecture for integrating available computer and communications security technologies into a system that meet these requirements is described. This architecture is meant as a starting point for discussion, rather that the final answer.

  20. Autoregulatory mechanisms controlling the Microprocessor.

    PubMed

    Triboulet, Robinson; Gregory, Richard I

    2010-01-01

    The Microprocessor, comprising the ribonuclease Drosha and its essential cofactor, the double-stranded RNA-binding protein, DGCR8, is essential for the first step of the miRNA biogenesis pathway. It specifically cleaves double-stranded RNA within stem-loop structures of primary miRNA transcripts (pri-miRNAs) to generate precursor (pre-miRNA) intermediates. Pre-miRNAs are subsequently processed by Dicer to their mature 22 nt form. Thus, Microprocessor is essential for miRNA maturation, and pri-miRNA cleavage by this complex defines one end of the mature miRNA. Moreover, it is emerging that dysregulation of the Microprocessor is associated with various human diseases. It is therefore important to understand the mechanisms by which the expression of the subunits of the Microprocessor is regulated. Recent findings have uncovered a post-transcriptional mechanism that maintains the integrity of the Microprocessor. These studies revealed that the Microprocessor is involved in the processing of the messenger RNA (mRNA) that encodes DGCR8. This regulatory feedback loop, along with the reported role played by DGCR8 in the stabilization of Drosha protein, is part ofa newly identified regulatory mechanism controlling Microprocessor activity.

  1. Autoregulatory mechanisms controlling the microprocessor.

    PubMed

    Triboulet, Robinson; Gregory, Richard I

    2011-01-01

    The Microprocessor, comprising the ribonuclease Drosha and its essential cofactor, the double-stranded RNA-binding protein, DGCR8, is essential for the first step of the miRNA biogenesis pathway. It specifically cleaves double-stranded RNA within stem-loop structures of primary miRNA transcripts (pri-miRNAs) to generate precursor (pre-miRNA) intermediates. Pre-miRNAs are subsequently processed by Dicer to their mature ∼22 nt form. Thus, Microprocessor is essential for miRNA maturation, and pri-miRNA cleavage by this complex defines one end of the mature miRNA. Moreover, it is emerging that dysregulation of the Microprocessor is associated with various human diseases. It is therefore important to understand the mechanisms by which the expression of the subunits of the Microprocessor is regulated. Recent findings have uncovered a post-transcriptional mechanism that maintains the integrity of the Microprocessor. These studies revealed that the Microprocessor is involved in the processing of the messenger RNA (mRNA) that encodes DGCR8. This regulatory feedback loop, along with the reported role played by DGCR8 in the stabilization of Drosha protein, is part of a newly identified regulatory mechanism controlling Microprocessor activity.

  2. Tag Content Access Control with Identity-based Key Exchange

    NASA Astrophysics Data System (ADS)

    Yan, Liang; Rong, Chunming

    2010-09-01

    Radio Frequency Identification (RFID) technology that used to identify objects and users has been applied to many applications such retail and supply chain recently. How to prevent tag content from unauthorized readout is a core problem of RFID privacy issues. Hash-lock access control protocol can make tag to release its content only to reader who knows the secret key shared between them. However, in order to get this shared secret key required by this protocol, reader needs to communicate with a back end database. In this paper, we propose to use identity-based secret key exchange approach to generate the secret key required for hash-lock access control protocol. With this approach, not only back end database connection is not needed anymore, but also tag cloning problem can be eliminated at the same time.

  3. Support of Research and Development Activities via the Internet: NASA's Access Mechanism.

    ERIC Educational Resources Information Center

    Duncan, Denise; And Others

    1993-01-01

    Describes a prototype information access system developed by NASA (National Aeronautics and Space Administration) called NAM (NASA Access Mechanism) to access the Internet for research and development activities. Topics addressed include the Science and Technical Information Program, information needs, networking requirements, functional and…

  4. Rural providers' access to online resources: a randomized controlled trial

    PubMed Central

    Hall, Laura J.; McElfresh, Karen R.; Warner, Teddy D.; Stromberg, Tiffany L.; Trost, Jaren; Jelinek, Devin A.

    2016-01-01

    Objective The research determined the usage and satisfaction levels with one of two point-of-care (PoC) resources among health care providers in a rural state. Methods In this randomized controlled trial, twenty-eight health care providers in rural areas were stratified by occupation and region, then randomized into either the DynaMed or the AccessMedicine study arm. Study participants were physicians, physician assistants, and nurses. A pre- and post-study survey measured participants' attitudes toward different information resources and their information-seeking activities. Medical student investigators provided training and technical support for participants. Data analyses consisted of analysis of variance (ANOVA), paired t tests, and Cohen's d statistic to compare pre- and post-study effects sizes. Results Participants in both the DynaMed and the AccessMedicine arms of the study reported increased satisfaction with their respective PoC resource, as expected. Participants in both arms also reported that they saved time in finding needed information. At baseline, both arms reported too little information available, which increased to “about right amounts of information” at the completion of the study. DynaMed users reported a Cohen's d increase of +1.50 compared to AccessMedicine users' reported use of 0.82. DynaMed users reported d2 satisfaction increases of 9.48 versus AccessMedicine satisfaction increases of 0.59 using a Cohen's d. Conclusion Participants in the DynaMed arm of the study used this clinically oriented PoC more heavily than the users of the textbook-based AccessMedicine. In terms of user satisfaction, DynaMed users reported higher levels of satisfaction than the users of AccessMedicine. PMID:26807050

  5. 30 CFR 816.66 - Use of explosives: Blasting signs, warnings, and access control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... schedule. (c) Access control. Access within the blasting area shall be controlled to prevent presence of..., and access control. 816.66 Section 816.66 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-SURFACE MINING ACTIVITIES § 816.66 Use of explosives: Blasting signs, warnings, and access...

  6. Integration of access control and ancillary information systems

    SciTech Connect

    Rodriguez, J.R.; Ahrens, J.S.

    1995-07-01

    The DOE has identified the Lawrence Livermore National Laboratory ARGUS system as the standard entry control system for the DOE Complex. ARGUS integrates several key functions, specifically, badging, entry control, and verification of clearance status. Not all sites need or can afford an ARGUS system. Such sites are therefore limited to commercial equipment which provide ARGUS like features. In this project an alternative way to integrate commercial equipment into an integrated system to include badging, access control, property control, and automated verification of clearance status has been investigated. Such a system would provide smaller sites the same functionality as is provided by ARGUS. Further, it would allow sites to fully participate in the DOE`s concept of Complex wide access control. This multi-year task is comprised of three phases. Phase 1, system requirements and definitions, and phase 2, software and hardware development, were completed during fiscal year 1994. This report covers these two phases and the demonstration system which resulted. Phase three would employ the demonstration system to evaluate system performance, identify operational limits and to integrate additional features. The demonstration system includes a badging station, a database server, a managers workstation, an entry control system, and a property protection system. The functions have been integrated through the use of custom interfaces and operator screens which greatly increase ease of use.

  7. Hand geometry biometric device for secure access control

    SciTech Connect

    Colbert, C.; Moles, D.R. )

    1991-01-01

    This paper reports that the authors developed for the Air Force the Mark VI Personal Identity Verifier (PIV) for controlling access to a fixed or mobile ICBM site, a computer terminal, or mainframe. The Mark VI records the digitized silhouettes of four fingers of each hand on an AT and T smart card. Like fingerprints, finger shapes, lengths, and widths constitute an unguessable biometric password. A Security Officer enrolls an authorized person who places each hand, in turn, on a backlighted panel. An overhead scanning camera records the right and left hand reference templates on the smart card. The Security Officer adds to the card: name, personal identification number (PIN), and access restrictions such as permitted days of the week, times of day, and doors. To gain access, cardowner inserts card into a reader slot and places either hand on the panel. Resulting access template is matched to the reference template by three sameness algorithms. The final match score is an average of 12 scores (each of the four fingers, matched for shape, length, and width), expressing the degree of sameness. (A perfect match would score 100.00.) The final match score is compared to a predetermined score (threshold), generating an accept or reject decision.

  8. Global Access-controlled Transfer e-frame (GATe)

    SciTech Connect

    2012-05-30

    Global Access-controlled Transfer e-frame (GATe) was designed to take advantage of the patterns that occur during an electronic record transfer process. The e-frame (or electronic framework or platform) is the foundation for developing secure information transfer to meet classified and unclassified business processes and is particularly useful when there is a need to share information with various entities in a controlled and secure environment. It can share, search, upload, download and retrieve sensitive information, as well as provides reporting capabilities.

  9. Access Scheme for Controlling Mobile Agents and its Application to Share Medical Information.

    PubMed

    Liao, Yu-Ting; Chen, Tzer-Shyong; Chen, Tzer-Long; Chung, Yu-Fang; Chen, Yu- Xin; Hwang, Jen-Hung; Wang, Huihui; Wei, Wei

    2016-05-01

    This study is showing the advantage of mobile agents to conquer heterogeneous system environments and contribute to a virtual integrated sharing system. Mobile agents will collect medical information from each medical institution as a method to achieve the medical purpose of data sharing. Besides, this research also provides an access control and key management mechanism by adopting Public key cryptography and Lagrange interpolation. The safety analysis of the system is based on a network attacker's perspective. The achievement of this study tries to improve the medical quality, prevent wasting medical resources and make medical resources access to appropriate configuration.

  10. A universal data access and protocol integration mechanism for smart home

    NASA Astrophysics Data System (ADS)

    Shao, Pengfei; Yang, Qi; Zhang, Xuan

    2013-03-01

    With the lack of standardized or completely missing communication interfaces in home electronics, there is no perfect solution to address every aspect in smart homes based on existing protocols and technologies. In addition, the central control unit (CCU) of smart home system working point-to-point between the multiple application interfaces and the underlying hardware interfaces leads to its complicated architecture and unpleasant performance. A flexible data access and protocol integration mechanism is required. The current paper offers a universal, comprehensive data access and protocol integration mechanism for a smart home. The universal mechanism works as a middleware adapter with unified agreements of the communication interfaces and protocols, offers an abstraction of the application level from the hardware specific and decoupling the hardware interface modules from the application level. Further abstraction for the application interfaces and the underlying hardware interfaces are executed based on adaption layer to provide unified interfaces for more flexible user applications and hardware protocol integration. This new universal mechanism fundamentally changes the architecture of the smart home and in some way meets the practical requirement of smart homes more flexible and desirable.

  11. A study of multiple access schemes in satellite control network

    NASA Astrophysics Data System (ADS)

    Mo, Zijian; Wang, Zhonghai; Xiang, Xingyu; Wang, Gang; Chen, Genshe; Nguyen, Tien; Pham, Khanh; Blasch, Erik

    2016-05-01

    Satellite Control Networks (SCN) have provided launch control for space lift vehicles; tracking, telemetry and commanding (TTC) for on-orbit satellites; and, test support for space experiments since the 1960s. Currently, SCNs encounter a new challenge: how to maintain the high reliability of services when sharing the spectrum with emerging commercial services. To achieve this goal, the capability of multiple satellites reception is deserved as an update/modernization of SCN in the future. In this paper, we conducts an investigation of multiple access techniques in SCN scenario, e.g., frequency division multiple access (FDMA) and coded division multiple access (CDMA). First, we introduce two upgrade options of SCN based on FDMA and CDMA techniques. Correspondingly, we also provide their performance analysis, especially the system improvement in spectrum efficiency and interference mitigation. Finally, to determine the optimum upgrade option, this work uses CRISP, i.e., Cost, Risk, Installation, Supportability and Performance, as the baseline approach for a comprehensive trade study of these two options. Extensive numerical and simulation results are presented to illustrate the theoretical development.

  12. 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.

  13. BARTER: Behavior Profile Exchange for Behavior-Based Admission and Access Control in MANETs

    NASA Astrophysics Data System (ADS)

    Frias-Martinez, Vanessa; Stolfo, Salvatore J.; Keromytis, Angelos D.

    Mobile Ad-hoc Networks (MANETs) are very dynamic networks with devices continuously entering and leaving the group. The highly dynamic nature of MANETs renders the manual creation and update of policies associated with the initial incorporation of devices to the MANET (admission control) as well as with anomaly detection during communications among members (access control) a very difficult task. In this paper, we present BARTER, a mechanism that automatically creates and updates admission and access control policies for MANETs based on behavior profiles. BARTER is an adaptation for fully distributed environments of our previously introduced BB-NAC mechanism for NAC technologies. Rather than relying on a centralized NAC enforcer, MANET members initially exchange their behavior profiles and compute individual local definitions of normal network behavior. During admission or access control, each member issues an individual decision based on its definition of normalcy. Individual decisions are then aggregated via a threshold cryptographic infrastructure that requires an agreement among a fixed amount of MANET members to change the status of the network. We present experimental results using content and volumetric behavior profiles computed from the ENRON dataset. In particular, we show that the mechanism achieves true rejection rates of 95% with false rejection rates of 9%.

  14. RiBAC: Role Interaction Based Access Control Model for Community Computing

    NASA Astrophysics Data System (ADS)

    Jung, Youna; Masoumzadeh, Amirreza; Joshi, James B. D.; Kim, Minkoo

    Community computing is an agent-based development paradigm for ubiquitous computing systems. In a community computing system, ubiquitous services are provided by cooperation among agents. While agents cooperate, they interact with each other continuously to access data of other agents and/or to execute other agent’s actions. However, in cases of security-critical ubiquitous services such as medical or military services, an access control mechanism is necessary to prevent unauthorized access to critical data or action. In this paper, we propose a family of Role interaction Based Access Control (RiBAC) models for Community Computing, by extending the existing RBAC model to consider role interactions. As a basic model, we propose the core RiBAC model. For the convenience of management and to provide more fine-grained access control, we propose Hierarchical RiBAC (H-RiBAC), Constrained RiBAC (C-RiBAC), and Constrained Hierarchical RiBAC (CH-RiBAC) models. Finally, we extend the existing community computing framework to accommodate the specification and enforcement of RiBAC policies.

  15. 30 CFR 817.66 - Use of explosives: Blasting signs, warnings, and access control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... notification required in § 817.64(a). (c) Access control. Access within the blasting areas shall be controlled..., and access control. 817.66 Section 817.66 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... control. (a) Blasting signs. Blasting signs shall meet the specifications of § 817.11. The operator...

  16. Privacy and Access Control for IHE-Based Systems

    NASA Astrophysics Data System (ADS)

    Katt, Basel; Breu, Ruth; Hafner, Micahel; Schabetsberger, Thomas; Mair, Richard; Wozak, Florian

    Electronic Health Record (EHR) is the heart element of any e-health system, which aims at improving the quality and efficiency of healthcare through the use of information and communication technologies. The sensitivity of the data contained in the health record poses a great challenge to security. In this paper we propose a security architecture for EHR systems that are conform with IHE profiles. In this architecture we are tackling the problems of access control and privacy. Furthermore, a prototypical implementation of the proposed model is presented.

  17. Efficient identity management and access control in cloud environment

    NASA Astrophysics Data System (ADS)

    Gloster, Jonathan

    2013-05-01

    As more enterprises are enticed to move data to a cloud environment to enhance data sharing and reduce operating costs by exploiting shared resources, concerns have risen over the ability to secure information within the cloud. This paper examines how a traditional Identity and Access Control (IDAM) architecture can be adapted to address security concerns of a cloud environment. We propose changing the paradigm of IDAM form a pure trust model to a risk based model will enable information to be protected securely in a cloud environment without impacting efficiencies of cloud environments.

  18. BTG-AC: Break-The-Glass Access Control Model for Medical Data in Wireless Sensor Networks.

    PubMed

    Maw, Htoo; Xiao, Hannan; Christianson, Bruce; Malcolm, James

    2015-12-22

    Wireless Sensor Networks (WSNs) have recently attracted much interest in the research community because of their wide range of applications. An emerging application for WSNs involves their use in healthcare where they are generally termed Wireless Medical Sensor Networks (WMSNs). In a hospital, outfitting every patient with tiny, wearable, wireless vital sign sensors would allow doctors, nurses and other caregivers to continuously monitor the state of their patients. In such a scenario, patients are expected to be treated in reasonable time, so, an access control model is needed which will provide both real-time access to comprehensive medical records and detect unauthorised access to sensitive data. In emergency situations, a doctor or nurse needs to access data immediately. The loss in data availability can result in further decline in the patient's condition or can even lead to death. Therefore, the availability of data is more important than any security concern in emergency situations. To address that research issue for medical data in WSNs, we propose the Break-The-Glass Access Control (BTG-AC) model that is a modified and redesigned version of the Break-The-Glass Role-Based Access Control (BTG-RBAC) model to address data availability issue and to detect the security policy violations from both authorised and unauthorised users. Several changes within the access control engine are made in BTG-RBAC in order to make the new BTG-AC to apply and fit in WSNs. This paper presents the detailed design and development of the BTG-AC model based on a healthcare scenario. The evaluation results show that the concepts of BTG, prevention and detection mechanism, and obligation provide more flexible access than other current access control models in WSNs. Additionally, we compare the BTG-AC model with an adaptive access control model (A2C) which has similar properties, for further evaluation. Alongside with the comparison, the advantages and disadvantages of BTGAC over

  19. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things

    PubMed Central

    Yi, Meng; Chen, Qingkui; Xiong, Neal N.

    2016-01-01

    This paper considers the distributed access and control problem of massive wireless sensor networks’ data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate. PMID:27827878

  20. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things.

    PubMed

    Yi, Meng; Chen, Qingkui; Xiong, Neal N

    2016-11-03

    This paper considers the distributed access and control problem of massive wireless sensor networks' data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  1. Accessibility

    EPA Pesticide Factsheets

    Federal laws, including Section 508 of the Rehabilitation Act, mandate that people with disabilities have access to the same information that someone without a disability would have. 508 standards cover electronic and information technology (EIT) products.

  2. 76 FR 67019 - Tenth Meeting: RTCA Special Committee 224, Airport Security Access Control

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... Federal Aviation Administration Tenth Meeting: RTCA Special Committee 224, Airport Security Access Control... RTCA Special Committee 224, Airport Security Access Control. SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224, Airport Security Access Control. DATES:...

  3. Tuneable Auxiliary Control Mechanisms For RUM Actuators

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.; Alhorn, Dean C.

    1995-01-01

    Tuneable auxiliary control mechanisms for rotating unbalanced-mass (RUM) actuators used to maximize scan amplitudes and/or minimize power consumption during changing conditions. This type of mechanism more sophisticated version of type of mechanism described in "Auxiliary Control Mechanisms for RUM Actuators" (MFS-28817). Torsional stiffness of torsionally flexible coupling made adjustable on command. Torsionally flexible coupling in tuneable version of auxiliary control mechanism adjustable by use of stepping-motor-driven worm-gear mechanism that varies bending length of flexible blade.

  4. BIOPACK: the ground controlled late access biological research facility.

    PubMed

    van Loon, Jack J W A

    2004-03-01

    Future Space Shuttle flights shall be characterized by activities necessary to further build the International Space Station, ISS. During these missions limited resources are available to conduct biological experiments in space. The Shuttles' Middeck is a very suitable place to conduct science during the ISS assembly missions or dedicated science missions. The BIOPACK, which flew its first mission during the STS-107, provides a versatile Middeck Locker based research tool for gravitational biology studies. The core facility occupies the space of only two Middeck Lockers. Experiment temperatures are controlled for bacteria, plant, invertebrate and mammalian cultures. Gravity levels and profiles can be set ranging from 0 to 2.0 x g on three independent centrifuges. This provides the experimenter with a 1.0 x g on-board reference and intermediate hypogravity and hypergravity data points to investigate e.g. threshold levels in biological responses. Temperature sensitive items can be stored in the facilities' -10 degrees C and +4 degrees C stowage areas. During STS-107 the facility also included a small glovebox (GBX) and passive temperature controlled units (PTCU). The GBX provides the experimenter with two extra levels of containment for safe sample handling. This biological research facility is a late access (L-10 hrs) laboratory, which, when reaching orbit, could automatically be starting up reducing important experiment lag-time and valuable crew time. The system is completely telecommanded when needed. During flight system parameters like temperatures, centrifuge speeds, experiment commanding or sensor readouts can be monitored and changed when needed. Although ISS provides a wide range of research facilities there is still need for an STS-based late access facility such as the BIOPACK providing experimenters with a very versatile research cabinet for biological experiments under microgravity and in-flight control conditions.

  5. A low-complexity medium access control framework for body sensor networks.

    PubMed

    Wang, Bo; Wang, Lei; Huang, Bang-Yu; Wu, Dan; Lin, Shao-Jie; Gu, Jia; Zhang, Yuan-Ting; Chen, Wei

    2009-01-01

    This paper proposed a low-complexity medium access control (MAC) protocol tailored for body sensor networks (BSN) applications. The MAC protocol was designated to handle collision avoidance by reducing the numbers of the overhead packets for handshake control within the BSN. We also suggested a novel message recovery mechanism for getting back the lost physiological information. The adaptive synchronization scheme we have implemented exploited the features of multiple data-rate and adjustable precision design to support differentiated healthcare applications. The MAC protocol was fully implemented using our BSN development platform. The experimental results suggested the improved MAC design was compact and energy-efficient.

  6. Cooling Mechanical Oscillators by Coherent Control

    NASA Astrophysics Data System (ADS)

    Frimmer, Martin; Gieseler, Jan; Novotny, Lukas

    2016-10-01

    In optomechanics, electromagnetic fields are harnessed to control a single mode of a mechanically compliant system, while other mechanical degrees of freedom remain unaffected due to the modes' mutual orthogonality and high quality factor. Extension of the optical control beyond the directly addressed mode would require a controlled coupling between mechanical modes. Here, we introduce an optically controlled coupling between two oscillation modes of an optically levitated nanoparticle. We sympathetically cool one oscillation mode by coupling it coherently to the second mode, which is feedback cooled. Furthermore, we demonstrate coherent energy transfer between mechanical modes and discuss its application for ground-state cooling.

  7. A Framework for Context Sensitive Risk-Based Access Control in Medical Information Systems.

    PubMed

    Choi, Donghee; Kim, Dohoon; Park, Seog

    2015-01-01

    Since the access control environment has changed and the threat of insider information leakage has come to the fore, studies on risk-based access control models that decide access permissions dynamically have been conducted vigorously. Medical information systems should protect sensitive data such as medical information from insider threat and enable dynamic access control depending on the context such as life-threatening emergencies. In this paper, we suggest an approach and framework for context sensitive risk-based access control suitable for medical information systems. This approach categorizes context information, estimating and applying risk through context- and treatment-based permission profiling and specifications by expanding the eXtensible Access Control Markup Language (XACML) to apply risk. The proposed framework supports quick responses to medical situations and prevents unnecessary insider data access through dynamic access authorization decisions in accordance with the severity of the context and treatment.

  8. Mechanical and thermal pretreatments of crushed tomatoes: effects on consistency and in vitro accessibility of lycopene.

    PubMed

    Tibäck, Evelina A; Svelander, Cecilia A; Colle, Ines J P; Altskär, Annika I; Alminger, Marie A G; Hendrickx, Marc E G; Ahrné, Lília M; Langton, Maud I B C

    2009-09-01

    The effects of mechanical and thermal treatments on the consistency and in vitro lycopene accessibility of crushed tomatoes were evaluated. Different crushing intensities and a subsequent heat treatment carried out as a heat shock (95 degrees C for 8 min) or a boiling step (100 degrees C for 20 min) were examined. Additional homogenization was compared with milder crushing regarding the effect on lycopene content and in vitro accessibility. Textural properties, polygalacturonase and pectinmethylesterase activity, pectin degree of methoxylation, lycopene content, and in vitro lycopene accessibility were evaluated. Microstructure was studied using both light and transmission electron microscopy. Crushing and subsequent heating affected the pectin degree of methoxylation and the consistency of the crushed tomatoes. The mechanical and thermal treatments did not affect the lycopene content to any great extent; however, in vitro accessibility seemed to improve with extensive crushing followed by heating. Crushing or homogenization in itself was not enough to increase in vitro lycopene accessibility.

  9. A study on new nursing information accessibility mechanism using the digital broadcasting network.

    PubMed

    Oh, Jina

    2006-01-01

    There have been efforts to add an interoperability function to TV systems. The digital technology has changed all our lifestyles. Now TV systems do indeed have interoperability functions. However, this means more than interoperable TV. It announces the birth of a digital broadcasting network (one-source and many-destination digital communication mechanism)--the new digital communication network as a broadcasting style. As a viewpoint of nursing informatics, this mechanism provides a new accessibility mechanism to structured and interoperable data. This paper introduces the technology and the basic scenarios on the data accessibility mechanism using the digital broadcasting network.

  10. Dynamic access control model for privacy preserving personalized healthcare in cloud environment.

    PubMed

    Son, Jiseong; Kim, Jeong-Dong; Na, Hong-Seok; Baik, Doo-Kwon

    2015-01-01

    When sharing and storing healthcare data in a cloud environment, access control is a central issue for preserving data privacy as a patient's personal health data may be accessed without permission from many stakeholders. Specifically, dynamic authorization for the access of data is required because personal health data is stored in cloud storage via wearable devices. Therefore, we propose a dynamic access control model for preserving the privacy of personal healthcare data in a cloud environment. The proposed model considers context information for dynamic access. According to the proposed model, access control can be dynamically determined by changing the context information; this means that even for a subject with the same role in the cloud, access permission is defined differently depending on the context information and access condition. Furthermore, we experiment the ability of the proposed model to provide correct responses by representing a dynamic access decision with real-life personalized healthcare system scenarios.

  11. 75 FR 69791 - Risk Management Controls for Brokers or Dealers With Market Access

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... CFR Part 240 Risk Management Controls for Brokers or Dealers With Market Access; Final Rule #0;#0... 3235-AK53 Risk Management Controls for Brokers or Dealers With Market Access AGENCY: Securities and... alternative trading system (``ATS''), including those providing sponsored or direct market access to...

  12. 75 FR 4007 - Risk Management Controls for Brokers or Dealers With Market Access

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-26

    ... COMMISSION 17 CFR Part 240 RIN 3235-AK53 Risk Management Controls for Brokers or Dealers With Market Access... market access to customers or other persons, to implement risk management controls and supervisory... growing popularity of sponsored or direct market access arrangements where broker-dealers allow...

  13. 78 FR 31627 - Twenty-Second Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ...: RTCA Special Committee 224, Airport Security Access Control Systems AGENCY: Federal Aviation... 224, Airport Security Access Control Systems. SUMMARY: The FAA is issuing this notice to advise the public of the twenty-second meeting of the RTCA Special Committee 224, Airport Security Access...

  14. 75 FR 80886 - Third Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-23

    ... Federal Aviation Administration Third Meeting: RTCA Special Committee 224: Airport Security Access Control... meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport Security Access...

  15. 78 FR 43963 - Twenty-Third Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    ... Federal Aviation Administration Twenty-Third Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held on June 20,...

  16. 76 FR 59481 - Ninth Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    ... TRANSPORTATION Federal Aviation Administration Ninth Meeting: RTCA Special Committee 224: Airport Security Access... Committee 224 meeting: Airport Security Access Control Systems. SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport Security Access Control...

  17. 77 FR 64838 - Sixteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-23

    ... Federal Aviation Administration Sixteenth Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held November 15,...

  18. 78 FR 16757 - Twentieth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-18

    ... Federal Aviation Administration Twentieth Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held April 4, 2013 from...

  19. 77 FR 15448 - Twelfth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-15

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Notice of meeting RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... 224, Airport Security Access Control Systems DATES: The meeting will be held April 5, 2012, from 10...

  20. 78 FR 22025 - Twenty First Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... Federal Aviation Administration Twenty First Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held April 9-10,...

  1. 77 FR 71474 - Seventeenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-30

    ... Federal Aviation Administration Seventeenth Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held December 13,...

  2. 77 FR 55894 - Fifteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... Federal Aviation Administration Fifteenth Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems DATES: The meeting will be held September 27-28,...

  3. 77 FR 2343 - Eleventh Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... Federal Aviation Administration Eleventh Meeting: RTCA Special Committee 224, Airport Security Access...). ACTION: Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY: The FAA..., Airport Security Access Control Systems. DATES: The meeting will be held February 9, 2012, from 10...

  4. 76 FR 16470 - Sixth Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... Federal Aviation Administration Sixth Meeting: RTCA Special Committee 224: Airport Security Access Control... meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport Security Access...

  5. 76 FR 9632 - Fifth Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-18

    ... Federal Aviation Administration Fifth Meeting: RTCA Special Committee 224: Airport Security Access Control... meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport Security Access...

  6. Investigating the mechanisms of seasonal ENSO phase locking bias in the ACCESS coupled model

    NASA Astrophysics Data System (ADS)

    Rashid, Harun A.; Hirst, Anthony C.

    2016-02-01

    The mechanisms of coupled model bias in seasonal ENSO phase locking are investigated using versions 1.0 and 1.3 of the CSIRO-BOM ACCESS coupled model (hereafter, ACCESS1.0 and ACCESS1.3, respectively). The two ACCESS coupled models are mostly similar in construction except for some differences, the most notable of which are in the cloud and land surface schemes used in the models. ACCESS1.0 simulates a realistic seasonal phase locking, with the ENSO variability peaking in December as in observations. On the other hand, the simulated ENSO variability in ACCESS1.3 peaks in March, a bias shown to be shared by many other CMIP5 models. To explore the mechanisms of this model bias, we contrast the atmosphere-ocean feedbacks associated with ENSO in both ACCESS model simulations and also compare the key feedbacks with those in other CMIP5 models. We find evidence that the ENSO phase locking bias in ACCESS1.3 is primarily caused by incorrect simulations of the shortwave feedback and the thermocline feedback in this model. The bias in the shortwave feedback is brought about by unrealistic SST-cloud interactions leading to a positive cloud feedback bias that is largest around March, in contrast to the strongest negative cloud feedback found in ACCESS1.0 simulations and observations at that time. The positive cloud feedback bias in ACCESS1.3 is the result of a dominant role played by the low-level clouds in its modeled SST-cloud interactions in the tropical eastern Pacific. Two factors appear to contribute to the dominance of low-level clouds in ACCESS1.3: the occurrence of a stronger mean descending motion bias and, to a lesser extent, a larger mean SST cold bias during March-April in ACCESS1.3 than in ACCESS1.0. A similar association is found between the positive cloud feedback bias and the biases in spring-time mean descending motion and SST for a group of CMIP5 models that show a seasonal phase locking bias similar to ACCESS1.3. Significant differences are also found

  7. Mechanically controlled radical polymerization initiated by ultrasound

    NASA Astrophysics Data System (ADS)

    Mohapatra, Hemakesh; Kleiman, Maya; Esser-Kahn, Aaron Palmer

    2016-10-01

    In polymer chemistry, mechanical energy degrades polymeric chains. In contrast, in nature, mechanical energy is often used to create new polymers. This mechanically stimulated growth is a key component of the robustness of biological materials. A synthetic system in which mechanical force initiates polymerization will provide similar robustness in polymeric materials. Here we show a polymerization of acrylate monomers initiated and controlled by mechanical energy provided by ultrasonic agitation. The activator for an atom-transfer radical polymerization is generated using piezochemical reduction of a Cu(II) precursor complex, which thus converts a mechanical activation of piezoelectric particles to the synthesis of a new material. This polymerization reaction has some characteristics of controlled radical polymerization, such as narrow molecular-weight distribution and linear dependence of the polymeric chain length on the time of mechanical activation. This new method of controlled radical polymerization complements the existing methods to synthesize commercially useful well-defined polymers.

  8. The influence of patriarchal behavior on birth control access and use among recent Hispanic immigrants.

    PubMed

    Gonzalez, Eleazar U; Sable, Marjorie R; Campbell, James D; Dannerbeck, Anne

    2010-08-01

    It is commonly assumed that Hispanic immigrants in the United States subscribe to a patriarchal ideology that keeps women subordinated to men, often through violence and exploitative reproductive behaviors. If this assumption is true, we might expect to find that in the Hispanic culture patriarchal males control decision-making about access to and use of birth control. Structured interviews of 100 Hispanic men and 100 Hispanic women who were recent immigrants to a Midwest community were conducted to examine this assumption. Results did not support this assumption among this study population. We found no patriarchal ideology supporting women's subordination to men, violence as a mechanism of control, reproduction as a way of exploitation, or cultural influences discouraging access to and use of birth control in the Hispanic community. Rather, these immigrants revealed adequate knowledge of birth control use and positive perceptions of gender equality. Gaining a better understanding of the limited influence of patriarchal ideology on the use of birth control and family planning services among this Hispanic community may inform the development of family planning services tailored for new Hispanic immigrants.

  9. Data Access, Ownership, and Control: Toward Empirical Studies of Access Practices.

    ERIC Educational Resources Information Center

    Hilgartner, Stephen; Brandt-Rauf, Sherry I.

    1994-01-01

    Examines how the new sociology of science can approach data access issues. A perspective is developed based on an analysis of the process of scientific production, data streams, and intellectual policy issues. (Contains 55 references.) (JLB)

  10. Bureau of Prisons access control system: functional and operational requirements

    NASA Astrophysics Data System (ADS)

    Janus, Michael; Carlson, Peter M.; Kane, Thomas

    1997-01-01

    The Federal Bureau of Prisons (BOP) operates 86 correctional institutions nationwide. The BOP has grown dramatically, the size of its inmate population growing from just over 41,000 inmates in 1987 to over 100,000 today. The number of BOP staff managing these facilities has grown correspondingly, more than doubling in number in the same ten year period. Technology has paid a major role in keeping up with this growth while maintaining high standards of security in BOP institutions. In an attempt to further enhance security in its institutions, the BOP has recently begun pilot testing an access control and entry system (ACES). ACES is intended to provide an automated record of very entry and exit to a correctional institution. ACES takes advantage of several methods of identifying an individual (inmate, staff or visitor) to assure that the individual exiting the institution is the same as the individual entering. The pilot test has raised a number of questions regarding the implementation of a technologically sophisticated system in a correctional institution. Questions of training, support, 'ownership,' cost effectiveness, and future potential all influence the deployment of this system. Preliminary results indicate that an adequate training and support system is essential to the performance of any sophisticated system and that other organizational issues need to be addressed before the decision to implement is made.

  11. Everywhere Access: Remote Control Software for the Internet.

    ERIC Educational Resources Information Center

    Beckett, George

    1994-01-01

    Describes a new software program called "Everywhere Access" that provides remote access to libraries' networked personal computers and that is suitable for use with the Internet. Highlights include installation; operation; security; standards issues; documentation and technical support; and potential uses and applications. (LRW)

  12. 33 CFR 105.255 - Security measures for access control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) All persons seeking unescorted access to secure areas must present their TWIC for inspection before being allowed unescorted access, in accordance with § 101.514 of this subchapter. Inspection must... screening or inspection; and (ii) Failure to consent or submit to screening or inspection will result...

  13. Electric power emergency management mechanism considering the access of new energy and renewable energy

    NASA Astrophysics Data System (ADS)

    Zhang, Baoqun; Ma, Longfei; Gong, Cheng; Jiao, Ran; Shi, Rui; Chi, Zhongjun; Ding, Yifeng

    2017-01-01

    Scholars at home and abroad have had a thorough research about the theory system and the frame of emergency management on the background of traditional grid, but for the improvement of the emergency mechanism when new energy and renewable energy access the grid, more work should be done. This paper will summarize the predecessors' work on emergency management, discuss the impact of emergency management while new energy and renewable energy access the grid and some suggestions are given.

  14. Tri-party agreement databases, access mechanism and procedures. Revision 2

    SciTech Connect

    Brulotte, P.J.

    1996-01-01

    This document contains the information required for the Washington State Department of Ecology (Ecology) and the U.S. Environmental Protection Agency (EPA) to access databases related to the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). It identifies the procedure required to obtain access to the Hanford Site computer networks and the Tri-Party Agreement related databases. It addresses security requirements, access methods, database availability dates, database access procedures, and the minimum computer hardware and software configurations required to operate within the Hanford Site networks. This document supersedes any previous agreements including the Administrative Agreement to Provide Computer Access to U.S. Environmental Protection Agency (EPA) and the Administrative Agreement to Provide Computer Access to Washington State Department of Ecology (Ecology), agreements that were signed by the U.S. Department of Energy (DOE), Richland Operations Office (RL) in June 1990, Access approval to EPA and Ecology is extended by RL to include all Tri-Party Agreement relevant databases named in this document via the documented access method and date. Access to databases and systems not listed in this document will be granted as determined necessary and negotiated among Ecology, EPA, and RL through the Tri-Party Agreement Project Managers. The Tri-Party Agreement Project Managers are the primary points of contact for all activities to be carried out under the Tri-Party Agreement. Action Plan. Access to the Tri-Party Agreement related databases and systems does not provide or imply any ownership on behalf of Ecology or EPA whether public or private of either the database or the system. Access to identified systems and databases does not include access to network/system administrative control information, network maps, etc.

  15. 10 CFR 20.1601 - Control of access to high radiation areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Control of access to high radiation areas. 20.1601 Section 20.1601 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1601 Control of access to high radiation areas....

  16. 10 CFR 20.1602 - Control of access to very high radiation areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation...

  17. 10 CFR 20.1602 - Control of access to very high radiation areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation...

  18. 10 CFR 20.1601 - Control of access to high radiation areas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Control of access to high radiation areas. 20.1601 Section 20.1601 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1601 Control of access to high radiation areas....

  19. 10 CFR 20.1601 - Control of access to high radiation areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Control of access to high radiation areas. 20.1601 Section 20.1601 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1601 Control of access to high radiation areas....

  20. 10 CFR 20.1602 - Control of access to very high radiation areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation...

  1. 10 CFR 20.1602 - Control of access to very high radiation areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation...

  2. 10 CFR 20.1602 - Control of access to very high radiation areas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Control of access to very high radiation areas. 20.1602 Section 20.1602 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1602 Control of access to very high radiation...

  3. 10 CFR 20.1601 - Control of access to high radiation areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Control of access to high radiation areas. 20.1601 Section 20.1601 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1601 Control of access to high radiation areas....

  4. 10 CFR 20.1601 - Control of access to high radiation areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Control of access to high radiation areas. 20.1601 Section 20.1601 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Control of Exposure From External Sources in Restricted Areas § 20.1601 Control of access to high radiation areas....

  5. 78 FR 7850 - Nineteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems. SUMMARY... Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held February 21,...

  6. A Network Access Control Framework for 6LoWPAN Networks

    PubMed Central

    Oliveira, Luís M. L.; Rodrigues, Joel J. P. C.; de Sousa, Amaro F.; Lloret, Jaime

    2013-01-01

    Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. PMID:23334610

  7. A network access control framework for 6LoWPAN networks.

    PubMed

    Oliveira, Luís M L; Rodrigues, Joel J P C; de Sousa, Amaro F; Lloret, Jaime

    2013-01-18

    Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes.

  8. Broadband passive optical network media access control protocols

    NASA Astrophysics Data System (ADS)

    Quayle, Alan

    1996-11-01

    Most telecommunication operators are currently deciding on how to respond to customers' needs stimulated by the synergy between compression coding of multimedia and the emergence of broadband digital networks. This paper describes a range of broadband access architectures under consideration in the full services access network initiative. All architectures have a common requirement for a broadband ATM PON. A common broadband PON applicable to many operators increases the world-wide market for the product. With greater production volumes manufacturers' costs reduce because of the experience curve effect making broadband access systems economic.

  9. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks

    PubMed Central

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-01-01

    Hybrid mobile applications (apps) combine the features of Web applications and “native” mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources—file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies “bridges” that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources—the ability to read and write contacts list, local files, etc.—to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign

  10. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks.

    PubMed

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-02-01

    Hybrid mobile applications (apps) combine the features of Web applications and "native" mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources-file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies "bridges" that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources-the ability to read and write contacts list, local files, etc.-to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign-origin Web content

  11. Mechanics and aerodynamics of insect flight control.

    PubMed

    Taylor, G K

    2001-11-01

    Insects have evolved sophisticated fight control mechanisms permitting a remarkable range of manoeuvres. Here, I present a qualitative analysis of insect flight control from the perspective of flight mechanics, drawing upon both the neurophysiology and biomechanics literatures. The current literature does not permit a formal, quantitative analysis of flight control, because the aerodynamic force systems that biologists have measured have rarely been complete and the position of the centre of gravity has only been recorded in a few studies. Treating the two best-known insect orders (Diptera and Orthoptera) separately from other insects, I discuss the control mechanisms of different insects in detail. Recent experimental studies suggest that the helicopter model of flight control proposed for Drosophila spp. may be better thought of as a facultative strategy for flight control, rather than the fixed (albeit selected) constraint that it is usually interpreted to be. On the other hand, the so-called 'constant-lift reaction' of locusts appears not to be a reflex for maintaining constant lift at varying angles of attack, as is usually assumed, but rather a mechanism to restore the insect to pitch equilibrium following a disturbance. Differences in the kinematic control mechanisms used by the various insect orders are related to differences in the arrangement of the wings, the construction of the flight motor and the unsteady mechanisms of lift production that are used. Since the evolution of insect flight control is likely to have paralleled the evolutionary refinement of these unsteady aerodynamic mechanisms, taxonomic differences in the kinematics of control could provide an assay of the relative importance of different unsteady mechanisms. Although the control kinematics vary widely between orders, the number of degrees of freedom that different insects can control will always be limited by the number of independent control inputs that they use. Control of the moments

  12. Age Related Decline in Postural Control Mechanisms.

    ERIC Educational Resources Information Center

    Stelmach, George E.; And Others

    1989-01-01

    Studied voluntary and reflexive mechanisms of postural control of young (N=8) and elderly (N=8) adults through measurement of reflexive reactions to large-fast and small-slow ankle rotation postural disturbances. Found reflexive mechanisms relatively intact for both groups although elderly appeared more disadvantaged when posture was under the…

  13. The Model and Control Methods of Access to Information and Technology Resources of Automated Control Systems in Water Supply Industry

    NASA Astrophysics Data System (ADS)

    Rytov, M. Yu; Spichyack, S. A.; Fedorov, V. P.; Petreshin, D. I.

    2017-01-01

    The paper describes a formalized control model of access to information and technological resources of automated control systems at water supply enterprises. The given model considers the availability of various communication links with information systems and technological equipment. There are also studied control methods of access to information and technological resources of automated control systems at water supply enterprises. On the basis of the formalized control model and appropriate methods there was developed a software-hardware complex for rapid access to information and technological resources of automated control systems, which contains an administrator’s automated workplace and ultimate users.

  14. Noise control mechanisms of inside aircraft

    NASA Astrophysics Data System (ADS)

    Zverev, A. Ya.

    2016-07-01

    World trends in the development of methods and approaches to noise reduction in aircraft cabins are reviewed. The paper discusses the mechanisms of passive and active noise and vibration control, application of "smart" and innovative materials, new approaches to creating all fuselage-design elements, and other promising directions of noise control inside aircraft.

  15. Damper mechanism for nuclear reactor control elements

    DOEpatents

    Taft, William Elwood

    1976-01-01

    A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping.

  16. Electric motor as the controlled mechanical transmission

    NASA Astrophysics Data System (ADS)

    Kukielka, Krzysztof

    2006-03-01

    The paper shows the possibility of using a brushless torque motor as controlled mechanical transmission. A development system for testing the torque motors was described and role of each component was discussed. Measured and observed phenomena of the research has shown the possibility of control the output rotations, preserving torque with simultaneous power consumption or its recovery, dependent on demanded transmission parameters.

  17. An effective access control approach to support mobility in IPv6 networks

    NASA Astrophysics Data System (ADS)

    Peng, Xue-hai; Lin, Chuang

    2005-11-01

    Access control is an important method to improve network security and prevent protected resources from being used by some nodes without authority. Moreover, mobility is an important trend of internet. In this paper, based on the architecture of hierarchical mobile IPv6, we proposed an effective access control approach to support mobility in IPv6 networks, which can ensure the operation of access control when a mobile node roams in these domains with different polices, with decreased delay of access negotiation and cost of delivering messages.

  18. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  19. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  20. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  1. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  2. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  3. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  4. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  5. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  6. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  7. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  8. Open access, readership, citations: a randomized controlled trial of scientific journal publishing.

    PubMed

    Davis, Philip M

    2011-07-01

    Does free access to journal articles result in greater diffusion of scientific knowledge? Using a randomized controlled trial of open access publishing, involving 36 participating journals in the sciences, social sciences, and humanities, we report on the effects of free access on article downloads and citations. Articles placed in the open access condition (n=712) received significantly more downloads and reached a broader audience within the first year, yet were cited no more frequently, nor earlier, than subscription-access control articles (n=2533) within 3 yr. These results may be explained by social stratification, a process that concentrates scientific authors at a small number of elite research universities with excellent access to the scientific literature. The real beneficiaries of open access publishing may not be the research community but communities of practice that consume, but rarely contribute to, the corpus of literature.

  9. Geometric control of quantum mechanical and nonlinear classical systems

    NASA Astrophysics Data System (ADS)

    Nelson, Richard Joseph

    1999-10-01

    Geometric control refers to the judicious use of the non- commuting nature of inputs and natural dynamics as the basis for control. The last few decades in control system theory have seen the application of differential geometry in proving several important properties of systems, including controllability and observability. Until recently, however, the results of this mathematical geometry have rarely been used as the basis for designing and implementing an actual controller. This thesis demonstrates the application of a judicious selection of inputs, so that if the system is proven to be controllable using geometric methods, one can design input sequences using the same geometry. A demonstration of this method is shown in simulating the attitude control of a satellite: a highly non-linear, non- holonomic control problem. Although not a practical method for large re-orientations of a typical satellite, the approach can be applied to other nonlinear systems. The method is also applied to the closed-loop performance of a quantum mechanical system to demonstrate the feasibility of coherent quantum feedback-something impossible using a conventional controller. Finally, the method is applied in the open-loop control of a quantum mechanical system: in this case, the creation of Greenberger-Horne-Zeilinger correlations among the nuclei of an ensemble of alanine molecules in a nuclear magnetic resonance spectrometer. In each case, the data demonstrate the usefulness of a geometric approach to control. In addition to demonstrations of geometric control in practice, the quantum mechanical experiments also demonstrate for the first time peculiar quantum correlations, including GHZ correlations, that have no classical analog. The quantum experiments further establish nuclear magnetic resonance as a viable and accessible testbed of quantum predictions and processes. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax

  10. Access control and privilege management in electronic health record: a systematic literature review.

    PubMed

    Jayabalan, Manoj; O'Daniel, Thomas

    2016-12-01

    This study presents a systematic literature review of access control for electronic health record systems to protect patient's privacy. Articles from 2006 to 2016 were extracted from the ACM Digital Library, IEEE Xplore Digital Library, Science Direct, MEDLINE, and MetaPress using broad eligibility criteria, and chosen for inclusion based on analysis of ISO22600. Cryptographic standards and methods were left outside the scope of this review. Three broad classes of models are being actively investigated and developed: access control for electronic health records, access control for interoperability, and access control for risk analysis. Traditional role-based access control models are extended with spatial, temporal, probabilistic, dynamic, and semantic aspects to capture contextual information and provide granular access control. Maintenance of audit trails and facilities for overriding normal roles to allow full access in emergency cases are common features. Access privilege frameworks utilizing ontology-based knowledge representation for defining the rules have attracted considerable interest, due to the higher level of abstraction that makes it possible to model domain knowledge and validate access requests efficiently.

  11. An antenna-pointing mechanism for the ETS-6 K-band Single Access (KSA) antenna

    NASA Technical Reports Server (NTRS)

    Takada, Noboru; Amano, Takahiro; Ohhashi, Toshiro; Wachi, Shigeo

    1991-01-01

    Both the design philosophy for the Antenna Pointing Mechanism (APM) to be used for the K-band Single Access (KSA) antenna system and experimental results of the APM Engineering Model (EM) tests are described. The KSA antenna system will be flown on the Engineering Test Satellite 6 (ETS-6).

  12. 36 CFR 1256.70 - What controls access to national security-classified information?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true What controls access to national security-classified information? 1256.70 Section 1256.70 Parks, Forests, and Public Property... controls access to national security-classified information? (a) The declassification of and public...

  13. 33 CFR 150.604 - Who controls access to medical monitoring and exposure records?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Who controls access to medical monitoring and exposure records? 150.604 Section 150.604 Navigation and Navigable Waters COAST GUARD... Health Safety and Health (general) § 150.604 Who controls access to medical monitoring and...

  14. 33 CFR 150.604 - Who controls access to medical monitoring and exposure records?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Who controls access to medical... Health Safety and Health (general) § 150.604 Who controls access to medical monitoring and exposure records? If medical monitoring is performed or exposure records are maintained by an employer, the...

  15. 75 FR 61819 - First Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ... meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this... Control Systems (Update to DO-230B): November 2, 2010 Welcome/Introductions/Administrative Remarks Agenda... Federal Aviation Administration First Meeting: RTCA Special Committee 224: Airport Security Access...

  16. 78 FR 51810 - Twenty-Fourth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-21

    ... Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control... RTCA Special Committee 224, Airport Security Access Control Systems. DATES: The meeting will be held on... TRANSPORTATION Federal Aviation Administration Twenty-Fourth Meeting: RTCA Special Committee 224,...

  17. 76 FR 50811 - Eighth Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... TRANSPORTATION Federal Aviation Administration Eighth Meeting: RTCA Special Committee 224: Airport Security... Committee 224 meeting: Airport Security Access Control Systems. SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport Security Access Control...

  18. 77 FR 25525 - Thirteenth Meeting: RTCA Special Committee 224, Airport Security Access Control Systems.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-30

    ... TRANSPORTATION Federal Aviation Administration Thirteenth Meeting: RTCA Special Committee 224, Airport Security... (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security Access Control Systems... Committee 224, Airport Security Access Control Systems DATES: The meeting will be held May 30, 2012, from...

  19. Controllable quantized conductance for multilevel data storage applications using conductive bridge random access memory.

    PubMed

    Aga, Fekadu Gochole; Woo, Jiyong; Song, Jeonghwan; Park, Jaehyuk; Lim, Seokjae; Sung, Changhyuck; Hwang, Hyunsang

    2017-03-17

    In this paper, we investigate the quantized conduction behavior of conductive bridge random access memory (CBRAM) with varied materials and ramping rates. We report stable and reproducible quantized conductance states with integer multiples of fundamental conductance obtained by optimizing the voltage ramping rate and the Ti-diffusion barrier (DB) at the Cu/HfO2 interface. Owing to controlled diffusion of Cu ions by the Ti-DB and the optimized ramping rate, through which it was possible to control the time delay of Cu ion reduction, more than seven levels of discrete conductance states were clearly observed. Analytical modeling was performed to determine the rate-limiting step in filament growth based on an electrochemical redox reaction. Our understanding of the fundamental mechanisms of quantized conductance behaviors provide a promising future for the multi-bit CBRAM device.

  20. Controllable quantized conductance for multilevel data storage applications using conductive bridge random access memory

    NASA Astrophysics Data System (ADS)

    Gochole Aga, Fekadu; Woo, Jiyong; Song, Jeonghwan; Park, Jaehyuk; Lim, Seokjae; Sung, Changhyuck; Hwang, Hyunsang

    2017-03-01

    In this paper, we investigate the quantized conduction behavior of conductive bridge random access memory (CBRAM) with varied materials and ramping rates. We report stable and reproducible quantized conductance states with integer multiples of fundamental conductance obtained by optimizing the voltage ramping rate and the Ti-diffusion barrier (DB) at the Cu/HfO2 interface. Owing to controlled diffusion of Cu ions by the Ti-DB and the optimized ramping rate, through which it was possible to control the time delay of Cu ion reduction, more than seven levels of discrete conductance states were clearly observed. Analytical modeling was performed to determine the rate-limiting step in filament growth based on an electrochemical redox reaction. Our understanding of the fundamental mechanisms of quantized conductance behaviors provide a promising future for the multi-bit CBRAM device.

  1. 33 CFR 104.265 - Security measures for access control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Requirements § 104.265 Security... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Security measures for access... security measures to: (1) Deter the unauthorized introduction of dangerous substances and...

  2. 33 CFR 104.265 - Security measures for access control.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Requirements § 104.265 Security... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Security measures for access... security measures to: (1) Deter the unauthorized introduction of dangerous substances and...

  3. 33 CFR 104.265 - Security measures for access control.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SECURITY MARITIME SECURITY MARITIME SECURITY: VESSELS Vessel Security Requirements § 104.265 Security... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Security measures for access... security measures to: (1) Deter the unauthorized introduction of dangerous substances and...

  4. 33 CFR 105.255 - Security measures for access control.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SECURITY MARITIME SECURITY MARITIME SECURITY: FACILITIES Facility Security Requirements § 105.255 Security... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Security measures for access... security measures to: (1) Deter the unauthorized introduction of dangerous substances and...

  5. Computer Control of a Random Access Slide Projector.

    ERIC Educational Resources Information Center

    Barker, Philip G.

    1982-01-01

    A description of a simple interface to enable the interconnection of a random access slide projector and a microcomputer is provided, as well as summaries of the role of slide images as a means of implementing graphic communication and the new activity in graphics as an area of information processing. The microcomputer interface is then detailed,…

  6. Scalable Machine Learning Framework for Behavior-Based Access Control

    DTIC Science & Technology

    2013-08-01

    rules. Dynamic events, such as subversion of credentials (e.g., theft of a Smart Card [3] such as the Common Access Card [4]) or changes in actor... Smart card handbook. Wiley, 2010. [4] DoD ID Card Reference Center, 2013, http://www.cac.mil/ [5] Hearst, Marti A., et al. "Support vector machines

  7. [Nitrogen metabolism and its control mechanisms].

    PubMed

    Bergner, H

    1989-01-01

    N intake in the form of protein has neither got an upper nor a lower limit for agricultural working animals within a diet and there is no control mechanism for it. A high surplus of certain amino acids results in a reduction of feed intake. N excretion in faeces depends on 1) the excretion of N containing indigestible feedstuffs, 2) bacterial nitrogen synthesis in the large intestine and 3) the excretion of true endogenous N containing substances (digestion enzymes, intestinal epithelium, N containing endogenous secretion). There are no other control mechanisms for N excretion in faeces. N excretion in urine mainly comprises the nitrogen from the degeneration of amino acids and nucleic acids. The interrelations between urea, NH3, allantoin, creatine and creatinine, uric acid and hippuric acid depend on the species (monogastric or ruminants), on the nitrogen and N amount consumed and on the recycling ratio of the amino acids. The absolute amount of N excretion is not subject to any control mechanism, it depends on the intake of protein and NPN substances, the interim stages, however, which lead to the formation of excretory products, are intermediately controlled. The most important interim stage is protein biosynthesis, which is a fixed, intermediately controlled value in maintenance level. Under growth conditions only, the protein synthesis quota can exceed the protein degradation quota of the total organism (positive N balance). The control mechanisms of protein biosynthesis have, according to current knowledge, the following structure: Stimulation: 1) growth hormone (STH) stimulates protein synthesis by means of somatomedins; 2) hormones of the thyroid gland (T4 and T3) are controlled by the hormone stimulating the thyroid gland (TSH); 3) insulin. Inhibition: 1) somatostatin inhibits STH, TSH and insulin; 2) cortisol directly inhibits protein synthesis and stimulates protein degradation. The control mechanisms of protein turnover in addition to genetic coding

  8. Remote controlled vacuum joint closure mechanism

    DOEpatents

    Doll, David W.; Hager, E. Randolph

    1986-01-01

    A remotely operable and maintainable vacuum joint closure mechanism for a noncircular aperture is disclosed. The closure mechanism includes an extendible bellows coupled at one end to a noncircular duct and at its other end to a flange assembly having sealed grooves for establishing a high vacuum seal with the abutting surface of a facing flange which includes an aperture forming part of the system to be evacuated. A plurality of generally linear arrangements of pivotally coupled linkages and piston combinations are mounted around the outer surface of the duct and aligned along the length thereof. Each of the piston/linkage assemblies is adapted to engage the flange assembly by means of a respective piston and is further coupled to a remote controlled piston drive shaft to permit each of the linkages positioned on a respective flat outer surface of the duct to simultaneously and uniformly displace a corresponding piston and the flange assembly with which it is in contact along the length of the duct in extending the bellows to provide a high vacuum seal between the movable flange and the facing flange. A plurality of latch mechanisms are also pivotally mounted on the outside of the duct. A first end of each of the latch mechanisms is coupled to a remotely controlled latch control shaft for displacing the latch mechanism about its pivot point. In response to the pivoting displacement of the latch mechanism, a second end thereof is displaced so as to securely engage the facing flange.

  9. Necessary security mechanisms in a PACS DICOM access system with web technology.

    PubMed

    Vázquez-Naya, José; Loureiro, Javier; Calle, Julián; Vidal, Jorge; Sierra, Alejandro

    2002-01-01

    The evolution in information and telecommunication technologies has allowed the development of systems that use the Internet infrastructure and Web technology to remotely access a hospital's picture archiving and communication system (PACS). However, one of the main problems in the construction of this type of system is the development of mechanisms that guarantee the security of the medical data that are being consulted. Most countries have specific norms for the protection of such medical data. This work describes security mechanisms that are developed in an access system to PACS DICOM with Web technology and comply with the Spanish legislation concerning the protection of medical data. The proposed security mechanisms are flexible, they leave room for the definition of security policies adjusted to the needs of each particular organization and they can be adapted to comply with new or foreign norms.

  10. Secure Remote Access Issues in a Control Center Environment

    NASA Technical Reports Server (NTRS)

    Pitts, Lee; McNair, Ann R. (Technical Monitor)

    2002-01-01

    The ISS finally reached an operational state and exists for local and remote users. Onboard payload systems are managed by the Huntsville Operations Support Center (HOSC). Users access HOSC systems by internet protocols in support of daily operations, preflight simulation, and test. In support of this diverse user community, a modem security architecture has been implemented. The architecture has evolved over time from an isolated but open system to a system which supports local and remote access to the ISS over broad geographic regions. This has been accomplished through the use of an evolved security strategy, PKI, and custom design. Through this paper, descriptions of the migration process and the lessons learned are presented. This will include product decision criteria, rationale, and the use of commodity products in the end architecture. This paper will also stress the need for interoperability of various products and the effects of seemingly insignificant details.

  11. Controls Over the Contractor Common Access Card Life Cycle

    DTIC Science & Technology

    2008-10-10

    Identification System SES Senior Executive Service SPOC Service Point of Contact TASM Trusted Agent Security Manager USD (AT&L) Under...the final report by October 31, 2008. 53 Finding D. Oversight of Common Access Card Sponsors DoD CVS Service Points of Contact ( SPOCs ...authorization to approve contractor CACs. Organization of CAC Application Sites Each Service agency has an SPOC who is responsible for coordinating with

  12. Proximity-based access control for context-sensitive information provision in SOA-based systems

    NASA Astrophysics Data System (ADS)

    Rajappan, Gowri; Wang, Xiaofei; Grant, Robert; Paulini, Matthew

    2014-06-01

    Service Oriented Architecture (SOA) has enabled open-architecture integration of applications within an enterprise. For net-centric Command and Control (C2), this elucidates information sharing between applications and users, a critical requirement for mission success. The Information Technology (IT) access control schemes, which arbitrate who gets access to what information, do not yet have the contextual knowledge to dynamically allow this information sharing to happen dynamically. The access control might prevent legitimate users from accessing information relevant to the current mission context, since this context may be very different from the context for which the access privileges were configured. We evaluate a pair of data relevance measures - proximity and risk - and use these as the basis of dynamic access control. Proximity is a measure of the strength of connection between the user and the resource. However, proximity is not sufficient, since some data might have a negative impact, if leaked, which far outweighs importance to the subject's mission. For this, we use a risk measure to quantify the downside of data compromise. Given these contextual measures of proximity and risk, we investigate extending Attribute-Based Access Control (ABAC), which is used by the Department of Defense, and Role-Based Access Control (RBAC), which is widely used in the civilian market, so that these standards-based access control models are given contextual knowledge to enable dynamic information sharing. Furthermore, we consider the use of such a contextual access control scheme in a SOA-based environment, in particular for net-centric C2.

  13. Specificity mechanisms in the control of transcription.

    PubMed

    von Hippel, P H; Rees, W A; Rippe, K; Wilson, K S

    1996-04-16

    In this overview we analyze and illustrate the principles underlying some of the specificity mechanisms that control the initiation, elongation, and termination phases of transcription. Thermodynamic mechanisms dominate in the first steps of initiation, where promoters at various levels of activation can be considered to be in competition for a limiting supply of core RNA polymerase. In the later stages of initiation, as well as in elongation and termination, the regulatory mechanisms that control specificity are largely kinetic, involving rate competition between branching reaction pathways where the outcome depends on the rates (and equilibria) of reaction and interconversion of different forms of the transcription complex. Elongation complexes are very stable at most positions along the DNA template, meaning that only RNA chain elongation (and editing) can occur at these positions. However, the stability of transcription complexes decreases abruptly when termination sequences are encountered, and here the outcome can be easily switched between elongation and termination (RNA release) by minor changes in the relative rates of these competing processes. Cis effectors, defined as sites at which regulatory proteins bind to upstream activation loci on either the DNA or the nascent RNA, play important roles in the control of both initiation and of the elongation-termination decision. Examples, drawn from studies of phage lambda N-dependent antitermination and E. coli rho-dependent termination processes, illustrate the flexibility and additivity of regulatory components within control mechanisms in transcription that involve multiple determinants. The generality of such regulatory principles are stressed.

  14. Stress controls the mechanics of collagen networks

    PubMed Central

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M.; Fabry, Ben; Weitz, David A.; MacKintosh, Fred C.

    2015-01-01

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress–strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks. PMID:26195769

  15. Stress controls the mechanics of collagen networks.

    PubMed

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M; Fabry, Ben; Weitz, David A; MacKintosh, Fred C

    2015-08-04

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress-strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks.

  16. Endoscope shaft-rigidity control mechanism: "FORGUIDE".

    PubMed

    Loeve, Arjo J; Plettenburg, Dick H; Breedveld, Paul; Dankelman, Jenny

    2012-02-01

    Recent developments in flexible endoscopy and other fields of medical technology have raised the need for compact slender shafts that can be made rigid and compliant at will. A novel compact mechanism, named FORGUIDE, with this functionality was developed. The FORGUIDE shaft rigidifies due to friction between a ring of cables situated between a spring and an inflated tube. A mathematical model for the FORGUIDE mechanism working principle was made and used to obtain understanding of this mechanism, predict the maximum rigidity of a FORGUIDE shaft design, and tune its design variables. The mathematical model gave suggestions for significant performance improvement by fine-tuning the design. A prototype FORGUIDE shaft was built and put to a series of bench tests. These tests showed that the FORGUIDE mechanism provides a reliable and simple way to control the rigidity of a flexible shaft.

  17. Fertility effects of abortion and birth control pill access for minors.

    PubMed

    Guldi, Melanie

    2008-11-01

    This article empirically assesses whether age-restricted access to abortion and the birth control pill influence minors' fertility in the United States. There is not a strong consensus in previous literature regarding the relationship between laws restricting minors' access to abortion and minors' birth rates. This is the first study to recognize that state laws in place prior to the 1973 Roe v. Wade decision enabled minors to legally consent to surgical treatment-including abortion-in some states but not in others, and to construct abortion access variables reflecting this. In this article, age-specific policy variables measure either a minor's legal ability to obtain an abortion or to obtain the birth control pill without parental involvement. I find fairly strong evidence that young women's birth rates dropped as a result of abortion access as well as evidence that birth control pill access led to a drop in birth rates among whites.

  18. 36 CFR 1256.70 - What controls access to national security-classified information?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false What controls access to national security-classified information? 1256.70 Section 1256.70 Parks, Forests, and Public Property... HISTORICAL MATERIALS Access to Materials Containing National Security-Classified Information § 1256.70...

  19. 36 CFR 1256.70 - What controls access to national security-classified information?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... national security-classified information? 1256.70 Section 1256.70 Parks, Forests, and Public Property... HISTORICAL MATERIALS Access to Materials Containing National Security-Classified Information § 1256.70 What controls access to national security-classified information? (a) The declassification of and public...

  20. 36 CFR 1256.70 - What controls access to national security-classified information?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... national security-classified information? 1256.70 Section 1256.70 Parks, Forests, and Public Property... HISTORICAL MATERIALS Access to Materials Containing National Security-Classified Information § 1256.70 What controls access to national security-classified information? (a) The declassification of and public...

  1. 36 CFR 1256.70 - What controls access to national security-classified information?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... national security-classified information? 1256.70 Section 1256.70 Parks, Forests, and Public Property... HISTORICAL MATERIALS Access to Materials Containing National Security-Classified Information § 1256.70 What controls access to national security-classified information? (a) The declassification of and public...

  2. 75 FR 71790 - Second Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-24

    ... Federal Aviation Administration Second Meeting: RTCA Special Committee 224: Airport Security Access... Committee 224 meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport...

  3. 76 FR 3931 - Fourth Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ... Federal Aviation Administration Fourth Meeting: RTCA Special Committee 224: Airport Security Access... Committee 224 Meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport...

  4. 76 FR 38742 - Seventh Meeting: RTCA Special Committee 224: Airport Security Access Control Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... Federal Aviation Administration Seventh Meeting: RTCA Special Committee 224: Airport Security Access... Committee 224 meeting: Airport Security Access Control Systems (Update to DO-230B). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 224: Airport...

  5. Remote controlled vacuum joint closure mechanism

    DOEpatents

    Doll, D.W.; Hager, E.R.

    1984-02-22

    A remotely operable and maintainable vacuum joint closure mechanism for a noncircular aperture is disclosed. The closure mechanism includes an extendible bellows coupled at one end to a noncircular duct and at its other end to a flange assembly having sealed grooves for establishing a high vacuum seal with the abutting surface of a facing flange which includes an aperture forming part of the system to be evacuated. A plurality of generally linear arrangements of pivotally coupled linkages and piston combinations are mounted around the outer surface of the duct and aligned along the length thereof. Each of the piston/linkage assemblies is adapted to engage the flange assembly by means of a respective piston and is further coupled to a remote controlled piston drive shaft to permit each of the linkages positioned on a respective flat outer surface of the duct to simultaneously and uniformly displace a corresponding piston and the flange assembly with which it is in contact along the length of the duct in extending the bellows to provide a high vacuum seal between the movable flange and the facing flange. A plurality of latch mechanisms are also pivotally mounted on the outside of the duct. A first end of each of the latch mechanisms is coupled to a remotely controlled latch control shaft for displacing the latch mechanism about its pivot point. In response to the pivoting displacement of the latch mechanism, a second end thereof is displaced so as to securely engage the facing flange and maintain the high vacuum seal established by the displacement of the flange assembly and extension of the bellows without displacing the entire duct.

  6. Fully Mechanically Controlled Automated Electron Microscopic Tomography

    PubMed Central

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-01-01

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins’ functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000–160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging. PMID:27403922

  7. Fully Mechanically Controlled Automated Electron Microscopic Tomography.

    PubMed

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-07-11

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins' functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000-160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.

  8. Fully Mechanically Controlled Automated Electron Microscopic Tomography

    NASA Astrophysics Data System (ADS)

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-07-01

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins’ functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000–160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.

  9. Poor readers' retrieval mechanism: efficient access is not dependent on reading skill

    PubMed Central

    Johns, Clinton L.; Matsuki, Kazunaga; Van Dyke, Julie A.

    2015-01-01

    A substantial body of evidence points to a cue-based direct-access retrieval mechanism as a crucial component of skilled adult reading. We report two experiments aimed at examining whether poor readers are able to make use of the same retrieval mechanism. This is significant in light of findings that poor readers have difficulty retrieving linguistic information (e.g., Perfetti, 1985). Our experiments are based on a previous demonstration of direct-access retrieval in language processing, presented in McElree et al. (2003). Experiment 1 replicates the original result using an auditory implementation of the Speed-Accuracy Tradeoff (SAT) method. This finding represents a significant methodological advance, as it opens up the possibility of exploring retrieval speeds in non-reading populations. Experiment 2 provides evidence that poor readers do use a direct-access retrieval mechanism during listening comprehension, despite overall poorer accuracy and slower retrieval speeds relative to skilled readers. The findings are discussed with respect to hypotheses about the source of poor reading comprehension. PMID:26528212

  10. Temperature-Controlled Clamping and Releasing Mechanism

    NASA Technical Reports Server (NTRS)

    Rosing, David; Ford, Virginia

    2005-01-01

    A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

  11. The Smart Card concept applied to access control

    SciTech Connect

    Seidman, S.

    1986-01-01

    Passwords tend to be handled carelessly, and so are easily lost or stolen. Because they are intangible, their loss or theft generally goes unnoticed. Because they are constant, they may be used by anyone for as long as they remain in active use by a legitimate user. A step up in password security is offered by a new range of products which generate a new code each time the device is used. Devices are being produced in packages as small as a standard plastic credit card, including internal battery power, integral keyboard and LCD display. Security features of the Smart Card are reviewed, and several random access code generators currently available in the commercial marketplace are described.

  12. 77 FR 26789 - Certain Semiconductor Chips Having Synchronous Dynamic Random Access Memory Controllers and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-07

    ... From the Federal Register Online via the Government Publishing Office ] INTERNATIONAL TRADE COMMISSION Certain Semiconductor Chips Having Synchronous Dynamic Random Access Memory Controllers and Products Containing Same; Determination Rescinding the Exclusion Order and Cease and Desist Orders...

  13. 75 FR 47464 - Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-06

    ... From the Federal Register Online via the Government Publishing Office LIBRARY OF CONGRESS Copyright Office 37 CFR Part 201 Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control Technologies AGENCY: Copyright Office, Library of Congress. ACTION: Final...

  14. Mechanical control of tissue and organ development

    PubMed Central

    Mammoto, Tadanori; Ingber, Donald E.

    2010-01-01

    Many genes and molecules that drive tissue patterning during organogenesis and tissue regeneration have been discovered. Yet, we still lack a full understanding of how these chemical cues induce the formation of living tissues with their unique shapes and material properties. Here, we review work based on the convergence of physics, engineering and biology that suggests that mechanical forces generated by living cells are as crucial as genes and chemical signals for the control of embryological development, morphogenesis and tissue patterning. PMID:20388652

  15. A contextual role-based access control authorization model for electronic patient record.

    PubMed

    Motta, Gustavo H M B; Furuie, Sergio S

    2003-09-01

    The design of proper models for authorization and access control for electronic patient record (EPR) is essential to a wide scale use of EPR in large health organizations. In this paper, we propose a contextual role-based access control authorization model aiming to increase the patient privacy and the confidentiality of patient data, whereas being flexible enough to consider specific cases. This model regulates user's access to EPR based on organizational roles. It supports a role-tree hierarchy with authorization inheritance; positive and negative authorizations; static and dynamic separation of duties based on weak and strong role conflicts. Contextual authorizations use environmental information available at access time, like user/patient relationship, in order to decide whether a user is allowed to access an EPR resource. This enables the specification of a more flexible and precise authorization policy, where permission is granted or denied according to the right and the need of the user to carry out a particular job function.

  16. Implementing the Victory Access Control Framework in a Military Ground Vehicle

    DTIC Science & Technology

    2015-08-01

    Attribute Markup Language (SAML) and eXtensible Access Control Markup Language (XACML). These technologies are typically used for securing an...interfaces. REFERENCES [1] OASIS, “Assertions and Protocols for the OASIS Security Assertion Markup Language (SAML) V2.0”, OASIS Standard...Online]. Available: http://docs.oasis- open.org/security/saml/v2.0/saml-core-2.0-os.pdf March 2005. [2] OASIS, “eXtensible Access Control Markup

  17. Springfield Processing Plant* (A Hypothetical Facility) SPP, Entry Control Point and Vehicle Gate Access Control Post Order

    SciTech Connect

    Baum, Gregory A.

    2014-06-01

    This hypothetical order provides the requirements and instructions for the Springfield Processing Plant (SPP) Vehicle Gate and Entry Control Point (ECP) in the perimeter access building. The purpose of this post is to prevent the theft, sabotage or diversion of nuclear material (NM), control access and exit at the protected area, and to respond to emergencies according the SPP Guard Force (GF) Contingency Plan and as directed by a Guard Force Supervisor.

  18. Increasing software testability with standard access and control interfaces

    NASA Technical Reports Server (NTRS)

    Nikora, Allen P; Some, Raphael R.; Tamir, Yuval

    2003-01-01

    We describe an approach to improving the testability of complex software systems with software constructs modeled after the hardware JTAG bus, used to provide visibility and controlability in testing digital circuits.

  19. Advanced Techniques for Deploying Reliable and Efficient Access Control: Application to E-healthcare.

    PubMed

    Jaïdi, Faouzi; Labbene-Ayachi, Faten; Bouhoula, Adel

    2016-12-01

    Nowadays, e-healthcare is a main advancement and upcoming technology in healthcare industry that contributes to setting up automated and efficient healthcare infrastructures. Unfortunately, several security aspects remain as main challenges towards secure and privacy-preserving e-healthcare systems. From the access control perspective, e-healthcare systems face several issues due to the necessity of defining (at the same time) rigorous and flexible access control solutions. This delicate and irregular balance between flexibility and robustness has an immediate impact on the compliance of the deployed access control policy. To address this issue, the paper defines a general framework to organize thinking about verifying, validating and monitoring the compliance of access control policies in the context of e-healthcare databases. We study the problem of the conformity of low level policies within relational databases and we particularly focus on the case of a medical-records management database defined in the context of a Medical Information System. We propose an advanced solution for deploying reliable and efficient access control policies. Our solution extends the traditional lifecycle of an access control policy and allows mainly managing the compliance of the policy. We refer to an example to illustrate the relevance of our proposal.

  20. Fuel injection pump with spill control mechanism

    SciTech Connect

    Djordjevic, I.

    1987-02-24

    This patent describes a rotary fuel injection pump for an internal combustion engine, having a housing, a rotor rotatable in the housing, a charge pump having radially extending plunger bores in the rotor and a plunger pump for each plunger bore having a pumping plunger reciprocable in the bore. The pumping plungers have outward fuel intake strokes and inward fuel delivery strokes for supplying high pressure charges of fuel for fuel injection. A cam ring surrounds the rotor and is engageable with the plunger pumps to reciprocate the plungers as the rotor rotates. Bumping plunger timing means relatively angularly adjusts the cam ring and rotor adjusting the pumping plunger timing. A spill control mechanism has spill valve means connected to the charge pump for spill control of the high pressure charges of fuel. The improvement described here wherein the spill valve means comprises at least one rotary spill valve having a valve bore in the rotor connected to the charge pump and a rotary spill valve member rotatably mounted within the valve bore. The spill control mechanism comprises first means for rotating each rotary spill valve member in unison with the rotor and in synchronism with the reciprocable movement of the pumping plungers for spill control of the high pressure charges of fuel. The pumping plunger timing means and the first means provide for separate relative angular adjustment of the cam ring and rotor and relative angular adjustment of the rotary spill valve member of at least the one rotary spill valve and the rotor.

  1. [Feedback control mechanisms of plant cell expansion

    SciTech Connect

    Cosgrove, D.J.

    1992-01-01

    We have generated considerable evidence for the significance of wall stress relaxation in the control of plant growth and found that several agents (gibberellin, light, genetic loci for dwarf stature) influence growth rate via alteration of wall relaxation. We have refined our methods for measuring wall relaxation and, moreover, have found that wall relaxation properties bear only a distance relationship to wall mechanical properties. We have garnered novel insights into the nature of cell expansion mechanisms by analyzing spontaneous fluctuations of plant growth rate in seedlings. These experiments involved the application of mathematical techniques for analyzing growth rate fluctuations and the development of new instrumentation for measuring and forcing plant growth in a controlled fashion. These studies conclude that growth rate fluctuations generated by the plant as consequence of a feedback control system. This conclusion has important implications for the nature of wall loosening processes and demands a different framework for thinking about growth control. It also implies the existence of a growth rate sensor.

  2. 76 FR 38293 - Risk Management Controls for Brokers or Dealers With Market Access

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    ... COMMISSION 17 CFR Part 240 RIN 3235-AK53 Risk Management Controls for Brokers or Dealers With Market Access... establish, document, and maintain a system of risk management controls and supervisory procedures that... develop, test, and implement the relevant risk management controls and supervisory procedures...

  3. 33 CFR 165.9 - Geographic application of limited and controlled access areas and regulated navigation areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and controlled access areas and regulated navigation areas. 165.9 Section 165.9 Navigation and... controlled access areas and regulated navigation areas. (a) General. The geographic application of the limited and controlled access areas and regulated navigation areas in this part are determined based...

  4. Cognitive Control and Lexical Access in Younger and Older Bilinguals

    ERIC Educational Resources Information Center

    Bialystok, Ellen; Craik, Fergus; Luk, Gigi

    2008-01-01

    Ninety-six participants, who were younger (20 years) or older (68 years) adults and either monolingual or bilingual, completed tasks assessing working memory, lexical retrieval, and executive control. Younger participants performed most of the tasks better than older participants, confirming the effect of aging on these processes. The effect of…

  5. Alternating access mechanisms of LeuT-fold transporters: trailblazing towards the promised energy landscapes.

    PubMed

    Kazmier, Kelli; Claxton, Derek P; Mchaourab, Hassane S

    2016-12-29

    Secondary active transporters couple the uphill translocation of substrates to electrochemical ion gradients. Transporter conformational motion, generically referred to as alternating access, enables a central ligand binding site to change its orientation relative to the membrane. Here we review themes of alternating access and the transduction of ion gradient energy to power this process in the LeuT-fold class of transporters where crystallographic, computational and spectroscopic approaches have converged to yield detailed models of transport cycles. Specifically, we compare findings for the Na(+)-coupled amino acid transporter LeuT and the Na(+)-coupled hydantoin transporter Mhp1. Although these studies have illuminated multiple aspects of transporter structures and dynamics, a number of questions remain unresolved that so far hinder understanding transport mechanisms in an energy landscape perspective.

  6. Trust-Based Access Control Model from Sociological Approach in Dynamic Online Social Network Environment

    PubMed Central

    Kim, Seungjoo

    2014-01-01

    There has been an explosive increase in the population of the OSN (online social network) in recent years. The OSN provides users with many opportunities to communicate among friends and family. Further, it facilitates developing new relationships with previously unknown people having similar beliefs or interests. However, the OSN can expose users to adverse effects such as privacy breaches, the disclosing of uncontrolled material, and the disseminating of false information. Traditional access control models such as MAC, DAC, and RBAC are applied to the OSN to address these problems. However, these models are not suitable for the dynamic OSN environment because user behavior in the OSN is unpredictable and static access control imposes a burden on the users to change the access control rules individually. We propose a dynamic trust-based access control for the OSN to address the problems of the traditional static access control. Moreover, we provide novel criteria to evaluate trust factors such as sociological approach and evaluate a method to calculate the dynamic trust values. The proposed method can monitor negative behavior and modify access permission levels dynamically to prevent the indiscriminate disclosure of information. PMID:25374943

  7. Trust-based access control model from sociological approach in dynamic online social network environment.

    PubMed

    Baek, Seungsoo; Kim, Seungjoo

    2014-01-01

    There has been an explosive increase in the population of the OSN (online social network) in recent years. The OSN provides users with many opportunities to communicate among friends and family. Further, it facilitates developing new relationships with previously unknown people having similar beliefs or interests. However, the OSN can expose users to adverse effects such as privacy breaches, the disclosing of uncontrolled material, and the disseminating of false information. Traditional access control models such as MAC, DAC, and RBAC are applied to the OSN to address these problems. However, these models are not suitable for the dynamic OSN environment because user behavior in the OSN is unpredictable and static access control imposes a burden on the users to change the access control rules individually. We propose a dynamic trust-based access control for the OSN to address the problems of the traditional static access control. Moreover, we provide novel criteria to evaluate trust factors such as sociological approach and evaluate a method to calculate the dynamic trust values. The proposed method can monitor negative behavior and modify access permission levels dynamically to prevent the indiscriminate disclosure of information.

  8. New Interference Mechanism Controls Ultracold Chemistry

    NASA Astrophysics Data System (ADS)

    Kendrick, Brian K.; Hazra, Jisha; Balakrishnan, N.

    2016-05-01

    A newly discovered interference mechanism has been shown to control the outcome of ultracold chemical reactions. The mechanism originates from the unique properties associated with ultracold collisions, namely: (1) isotropic (s-wave) scattering and (2) an effective quantization of the scattering phase shift (which originates from the bound state structure of the molecule). These two properties can lead to maximum constructive or destructive interference between two interfering reaction pathways (such as exchange and non-exchange in systems with two or more identical nuclei). If the molecular system exhibits a conical intersection, then the associated geometric phase is shown to act as a ``quantum switch'' which can turn the reactivity on or off. Reaction rate coefficients for the O + OH --> H + O2 and H + H2, reactions are presented which explicitly demonstrate the effect. Experimentalists might exploit this new mechanism to control ultracold reactions by the application of external electric or magnetic fields or by the selection of a particular nuclear spin state. This work was supported in part by the LDRD program (Grant No. 20140309ER) at LANL (B.K.) and by NSF Grant PHY-1505557 (N.B.) and ARO MURI Grant No. W911NF-12-1-0476 (N.B.).

  9. Stirling engine control mechanism and method

    DOEpatents

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  10. Optimal Control of Active Recoil Mechanisms

    DTIC Science & Technology

    1977-02-01

    forces from 25 to 2.5% for lower zones and cavitation was avoided for zone 8. Tachometer feedback was shown to be effective for low zones. The...concept of feedback control system coupled with optimization procedure to design recoil mechanisms was demonstrated to be an efficient and very effective ...122o •nl260 .01300 .01340 .01380 • ouzo #01460 •01500 •01540 •01580 •0162" .0166 i 309o,6 504P.6 9964.5 10075,9 39121.5 75397.3

  11. The Technology Information Environment with Industry (TIE-In): A mechanism for accessing laboratory solutions

    SciTech Connect

    Ang, J.A.; Machin, G.D.; Marek, E.L.

    1994-12-31

    The Technology Information Environment with Industry (TIE-In) is a system that helps users obtain laboratory-developed technical solutions without requiring that they duplicate the technical resources (in people, hardware and software) at the national laboratories. TIE-In is based on providing users with controlled access to distributed laboratory resources that are packaged in intelligent user interfaces. These interfaces help users obtain technical solutions without requiring that the user have specialized technical and computer expertise. As a designated DOE Technology Deployment Center/User Facility, industry users can access a broad range of laboratory-developed technologies on a cost-recovery basis. TIE-In will also be used to share laboratory resources with partners in US industry that help the DOE meet future manufacturing needs for the stewardship of our nation`s nuclear weapons stockpile.

  12. The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

    NASA Astrophysics Data System (ADS)

    Lamontanara, Allan Joaquim; Georgeon, Sandrine; Tria, Giancarlo; Svergun, Dmitri I.; Hantschel, Oliver

    2014-11-01

    The activity of protein kinases is regulated by multiple molecular mechanisms, and their disruption is a common driver of oncogenesis. A central and almost universal control element of protein kinase activity is the activation loop that utilizes both conformation and phosphorylation status to determine substrate access. In this study, we use recombinant Abl tyrosine kinases and conformation-specific kinase inhibitors to quantitatively analyse structural changes that occur after Abl activation. Allosteric SH2-kinase domain interactions were previously shown to be essential for the leukemogenesis caused by the Bcr-Abl oncoprotein. We find that these allosteric interactions switch the Abl activation loop from a closed to a fully open conformation. This enables the trans-autophosphorylation of the activation loop and requires prior phosphorylation of the SH2-kinase linker. Disruption of the SH2-kinase interaction abolishes activation loop phosphorylation. Our analysis provides a molecular mechanism for the SH2 domain-dependent activation of Abl that may also regulate other tyrosine kinases.

  13. Advanced Guidance and Control for Hypersonics and Space Access

    NASA Technical Reports Server (NTRS)

    Hanson, John M.; Hall, Charles E.; Mulqueen, John A.; Jones, Robert E.

    2003-01-01

    Advanced guidance and control (AG&C) technologies are critical for meeting safety, reliability, and cost requirements for the next generation of reusable launch vehicle (RLV), whether it is fully rocket-powered or has air- breathing components. This becomes clear upon examining the number of expendable launch vehicle failures in the recent past where AG&C technologies could have saved a RLV with the same failure mode, the additional vehicle problems where t h i s technology applies, and the costs and time associated with mission design with or without all these failure issues. The state-of-the-art in guidance and control technology, as well as in computing technology, is the point where we can look to the possibility of being able to safely return a RLV in any situation where it can physically be recovered. This paper outlines reasons for AWC, current technology efforts, and the additional work needed for making this goal a reality. There are a number of approaches to AG&C that have the potential for achieving the desired goals. For some of these methods, we compare the results of tests designed to demonstrate the achievement of the goals. Tests up to now have been focused on rocket-powered vehicles; application to hypersonic air-breathers is planned. We list the test cases used to demonstrate that the desired results are achieved, briefly describe an automated test scoring method, and display results of the tests. Some of the technology components have reached the maturity level where they are ready for application to a new vehicle concept, while others are not far along in development.

  14. Dynamic congestion control mechanisms for MPLS networks

    NASA Astrophysics Data System (ADS)

    Holness, Felicia; Phillips, Chris I.

    2001-02-01

    Considerable interest has arisen in congestion control through traffic engineering from the knowledge that although sensible provisioning of the network infrastructure is needed, together with sufficient underlying capacity, these are not sufficient to deliver the Quality of Service required for new applications. This is due to dynamic variations in load. In operational Internet Protocol (IP) networks, it has been difficult to incorporate effective traffic engineering due to the limited capabilities of the IP technology. In principle, Multiprotocol Label Switching (MPLS), which is a connection-oriented label swapping technology, offers new possibilities in addressing the limitations by allowing the operator to use sophisticated traffic control mechanisms. This paper presents a novel scheme to dynamically manage traffic flows through the network by re-balancing streams during periods of congestion. It proposes management-based algorithms that will allow label switched routers within the network to utilize mechanisms within MPLS to indicate when flows are starting to experience frame/packet loss and then to react accordingly. Based upon knowledge of the customer's Service Level Agreement, together with instantaneous flow information, the label edge routers can then instigate changes to the LSP route and circumvent congestion that would hitherto violate the customer contacts.

  15. 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

  16. Electrochemical biofilm control: mechanism of action

    PubMed Central

    Istanbullu, Ozlem; Babauta, Jerome; Nguyen, Hung Duc; Beyenal, Haluk

    2014-01-01

    Although it has been previously demonstrated that an electrical current can be used to control biofilm growth on metal surfaces, the literature results are conflicting and there is no accepted mechanism of action. One of the suggested mechanisms is the production of hydrogen peroxide (H2O2) on metal surfaces. However, there are literature studies in which H2O2 could not be detected in the bulk solution. This is most likely because H2O2 was produced at a low concentration near the surface and could not be detected in the bulk solution. The goals of this research were (1) to develop a well-controlled system to explain the mechanism of action of the bioelectrochemical effect on 316L stainless steel (SS) surfaces and (2) to test whether the produced H2O2 can reduce cell growth on metal surfaces. It was found that H2O2 was produced near 316L SS surfaces when a negative potential was applied. The H2O2 concentration increased towards the surface, while the dissolved oxygen decreased when the SS surface was polarized to −600 mVAg/AgCl. When polarized and non-polarized surfaces with identical Pseudomonas aeruginosa PAO1 biofilms were continuously fed with air-saturated growth medium, the polarized surfaces showed minimal biofilm growth while there was significant biofilm growth on the non-polarized surfaces. Although there was no detectable H2O2 in the bulk solution, it was found that the surface concentration of H2O2 was able to prevent biofilm growth. PMID:22827804

  17. Analysis of Decision Factors for the Application of Information Access Controls within the Organization

    ERIC Educational Resources Information Center

    Foerster, Carl A.

    2013-01-01

    The application of access controls on internal information necessarily impacts the availability of that information for sharing inside the enterprise. The decisions establishing the degree of control are a crucial first step to balance the requirements to protect and share. This research develops a set of basic decision factors and examines other…

  18. Performance analysis and overload control of an open service access (OSA) architecture

    NASA Astrophysics Data System (ADS)

    Andersson, Jens K.; Nyberg, Christian; Kihl, Maria

    2003-08-01

    The trend of the service architectures developed in telecommunications today is that they should be open in the sense that they can communicate over the borders of different networks. Instead of each network having their own service architecture with their own applications, all networks should be able to use the same applications. 3GPP, the organization developing specifications for the 3G networks has specified the standard Open Service Access (OSA), as a part of the 3G specification. OSA offers different Application Protocol Interfaces that enable an application that resides outside a network to use the capabilities of the network. This paper analyses the performance of an OSA gateway. It is examined how the overload control can be dealt with in a way to best satisfy the operators and the 3'rd parties. There are some guiding principles in the specifications, but a lot of decisions have to be made by the implementors of application servers and OSA gateways. Proposals of different requirements for an OSA architecture exist such as, minimum amount of accepted calls per second and time constraint for the maximal total delay for an application. Maximal and fair throughput have to be prioritized from the 3'rd parties view, but profit is the main interest from the operators point of view. Therefore this paper examines a priority based proposal of an overload control mechanism taking these aspects and requirements into account.

  19. MAAC: a software tool for user authentication and access control to the electronic patient record in an open distributed environment

    NASA Astrophysics Data System (ADS)

    Motta, Gustavo H.; Furuie, Sergio S.

    2004-04-01

    Designing proper models for authorization and access control for the electronic patient record (EPR) is essential to wide scale use of the EPR in large health organizations. This work presents MAAC (Middleware for Authentication and Access Control), a tool that implements a contextual role-based access control (RBAC) authorization model. RBAC regulates user"s access to computers resources based on their organizational roles. A contextual authorization uses environmental information available at access-request time, like user/patient relationship, in order to decide whether a user has the right to access an EPR resource. The software architecture where MAAC is implemented uses Lightweight Directory Access Protocol, Java programming language and the CORBA/OMG standards CORBA Security Service and Resource Access Decision Facility. With those open and distributed standards, heterogeneous EPR components can request user authentication and access authorization services in a unified and consistent fashion across multiple platforms.

  20. A nomadic access mechanism for enabling dynamic video surveillance over IEEE 802.15.4 networks

    NASA Astrophysics Data System (ADS)

    Garcia-Sanchez, Felipe; Garcia-Sanchez, Antonio-Javier; Losilla, Fernando; Garcia-Haro, Joan

    2010-12-01

    IEEE 802.15.4 networking technology is designed to be the common standard for integrating WSN applications in heterogeneous environments. However, applications considering mobile nodes along with strict temporal requirements, such as those required for video transmission, are an unexplored field for this technology. These applications involve different challenges and issues that the direct employment of the IEEE 802.15.4 standard does not resolve. Therefore, in this paper a cross-layer mechanism consisting of application and medium access arbitration is presented, enabling the efficient connection and operation of mobile nodes together with the transmission of video flows. The proposed mechanism is evaluated via simulation and its feasibility checked by means of a first prototype. The study of power consumption is also taken into account and so are the quality of service parameters and the human quality perception of the received video stream. The results obtained are presented and further discussed.

  1. Characteristics and mechanism study of cerium oxide based random access memories

    SciTech Connect

    Hsieh, Cheng-Chih; Roy, Anupam; Rai, Amritesh; Chang, Yao-Feng; Banerjee, Sanjay K.

    2015-04-27

    In this work, low operating voltage and high resistance ratio of different resistance states of binary transition metal oxide based resistive random access memories (RRAMs) are demonstrated. Binary transition metal oxides with high dielectric constant have been explored for RRAM application for years. However, CeO{sub x} is considered as a relatively new material to other dielectrics. Since research on CeO{sub x} based RRAM is still at preliminary stage, fundamental characteristics of RRAM such as scalability and mechanism studies need to be done before moving further. Here, we show very high operation window and low switching voltage of CeO{sub x} RRAMs and also compare electrical performance of Al/CeO{sub x}/Au system between different thin film deposition methods and discuss characteristics and resistive switching mechanism.

  2. The Use of a Computer-Controlled Random Access Slide Projector for Rapid Information Display.

    ERIC Educational Resources Information Center

    Muller, Mark T.

    A 35mm random access slide projector operated in conjunction with a computer terminal was adapted to meet the need for a more rapid and complex graphic display mechanism than is currently available with teletypewriter terminals. The model projector can be operated manually to provide for a maintenance checkout of the electromechanical system.…

  3. Spatial constancy mechanisms in motor control

    PubMed Central

    Medendorp, W. Pieter

    2011-01-01

    The success of the human species in interacting with the environment depends on the ability to maintain spatial stability despite the continuous changes in sensory and motor inputs owing to movements of eyes, head and body. In this paper, I will review recent advances in the understanding of how the brain deals with the dynamic flow of sensory and motor information in order to maintain spatial constancy of movement goals. The first part summarizes studies in the saccadic system, showing that spatial constancy is governed by a dynamic feed-forward process, by gaze-centred remapping of target representations in anticipation of and across eye movements. The subsequent sections relate to other oculomotor behaviour, such as eye–head gaze shifts, smooth pursuit and vergence eye movements, and their implications for feed-forward mechanisms for spatial constancy. Work that studied the geometric complexities in spatial constancy and saccadic guidance across head and body movements, distinguishing between self-generated and passively induced motion, indicates that both feed-forward and sensory feedback processing play a role in spatial updating of movement goals. The paper ends with a discussion of the behavioural mechanisms of spatial constancy for arm motor control and their physiological implications for the brain. Taken together, the emerging picture is that the brain computes an evolving representation of three-dimensional action space, whose internal metric is updated in a nonlinear way, by optimally integrating noisy and ambiguous afferent and efferent signals. PMID:21242137

  4. Automated biometric access control system for two-man-rule enforcement

    SciTech Connect

    Holmes, J.P.; Maxwell, R.L. ); Henderson, R.W. )

    1991-01-01

    This paper describes a limited access control system for nuclear facilities which makes use of the eye retinal identity verifier to control the passage of personnel into and out of one or a group of security controlled working areas. This access control system requires no keys, cards or credentials. The user simply enters his Personal Identification Number (PIN) and takes an eye reading to request passage. The PIN does not have to be kept secret. The system then relies on biometric identity verification of the user, along with other system information, to make the decision of whether or not to unlock the door. It also enforces multiple zones control with personnel tracking and the two-man-rule.

  5. Accessibility to tuberculosis control services and tuberculosis programme performance in southern Ethiopia

    PubMed Central

    Dangisso, Mesay Hailu; Datiko, Daniel Gemechu; Lindtjørn, Bernt

    2015-01-01

    Background Despite the expansion of health services and community-based interventions in Ethiopia, limited evidence exists about the distribution of and access to health facilities and their relationship with the performance of tuberculosis (TB) control programmes. We aim to assess the geographical distribution of and physical accessibility to TB control services and their relationship with TB case notification rates (CNRs) and treatment outcome in the Sidama Zone, southern Ethiopia. Design We carried out an ecological study to assess physical accessibility to TB control facilities and the association of physical accessibility with TB CNRs and treatment outcome. We collected smear-positive pulmonary TB (PTB) cases treated during 2003–2012 from unit TB registers and TB service data such as availability of basic supplies for TB control and geographic locations of health services. We used ArcGIS 10.2 to measure the distance from each enumeration location to the nearest TB control facilities. A linear regression analysis was employed to assess factors associated with TB CNRs and treatment outcome. Results Over a decade the health service coverage (the health facility–to-population ratio) increased by 36% and the accessibility to TB control facilities also improved. Thus, the mean distance from TB control services was 7.6 km in 2003 (ranging from 1.8 to 25.5 km) between kebeles (the smallest administrative units) and had decreased to 3.2 km in 2012 (ranging from 1.5 to 12.4 km). In multivariate linear regression, as distance from TB diagnostic facilities (b-estimate=−0.25, p<0.001) and altitude (b-estimate=−0.31, p<0.001) increased, the CNRs of TB decreased, whereas a higher population density was associated with increased TB CNRs. Similarly, distance to TB control facilities (b-estimate=−0.27, p<0.001) and altitude (b-estimate=−0.30, p<0.001) were inversely associated with treatment success (proportion of treatment completed or cured cases). Conclusions

  6. Access Nets: Modeling Access to Physical Spaces

    NASA Astrophysics Data System (ADS)

    Frohardt, Robert; Chang, Bor-Yuh Evan; Sankaranarayanan, Sriram

    Electronic, software-managed mechanisms using, for example, radio-frequency identification (RFID) cards, enable great flexibility in specifying access control policies to physical spaces. For example, access rights may vary based on time of day or could differ in normal versus emergency situations. With such fine-grained control, understanding and reasoning about what a policy permits becomes surprisingly difficult requiring knowledge of permission levels, spatial layout, and time. In this paper, we present a formal modeling framework, called AccessNets, suitable for describing a combination of access permissions, physical spaces, and temporal constraints. Furthermore, we provide evidence that model checking techniques are effective in reasoning about physical access control policies. We describe our results from a tool that uses reachability analysis to validate security policies.

  7. Developing Access Control Model of Web OLAP over Trusted and Collaborative Data Warehouses

    NASA Astrophysics Data System (ADS)

    Fugkeaw, Somchart; Mitrpanont, Jarernsri L.; Manpanpanich, Piyawit; Juntapremjitt, Sekpon

    This paper proposes the design and development of Role- based Access Control (RBAC) model for the Single Sign-On (SSO) Web-OLAP query spanning over multiple data warehouses (DWs). The model is based on PKI Authentication and Privilege Management Infrastructure (PMI); it presents a binding model of RBAC authorization based on dimension privilege specified in attribute certificate (AC) and user identification. Particularly, the way of attribute mapping between DW user authentication and privilege of dimensional access is illustrated. In our approach, we apply the multi-agent system to automate flexible and effective management of user authentication, role delegation as well as system accountability. Finally, the paper culminates in the prototype system A-COLD (Access Control of web-OLAP over multiple DWs) that incorporates the OLAP features and authentication and authorization enforcement in the multi-user and multi-data warehouse environment.

  8. Pace: Privacy-Protection for Access Control Enforcement in P2P Networks

    NASA Astrophysics Data System (ADS)

    Sánchez-Artigas, Marc; García-López, Pedro

    In open environments such as peer-to-peer (P2P) systems, the decision to collaborate with multiple users — e.g., by granting access to a resource — is hard to achieve in practice due to extreme decentralization and the lack of trusted third parties. The literature contains a plethora of applications in which a scalable solution for distributed access control is crucial. This fact motivates us to propose a protocol to enforce access control, applicable to networks consisting entirely of untrusted nodes. The main feature of our protocol is that it protects both sensitive permissions and sensitive policies, and does not rely on any centralized authority. We analyze the efficiency (computational effort and communication overhead) as well as the security of our protocol.

  9. A mechanism for enhancing ionic accessibility into selective ion exchange resins

    SciTech Connect

    Alexandratos, S.D.; Shelley, C.A.; Horwitz, E.P.; Chiarizia, R.

    1998-07-01

    A bifunctional monophosphonic/sulfonic acid ion exchange resin with high capacity has been synthesized. Metal ion studies have been carried out with europium, americium, and ferric nitrate in solutions of varying acidity, with and without sodium nitrate added. The bifunctional resin complexes far higher levels of Eu(III) from 0.5 and 1 N nitric acid than the monofunctional phosphonic acid resin. It is postulated that the sulfonic acid ligand provides an access mechanism for the metal ions into the polymer matrix by hydrating the matrix and preventing its collapse in high ionic strength solutions thus allowing for rapid ionic complexation by the selective phosphonic acid ligands. The bifunctional monophosphonic/sulfonic acid resin has both ligands bound to a polystyrene support. It complexes higher levels of metal ions than a comparable resin differing only by having the monophosphonic acid ligand directly bound to the C-C backbone. Results are compared to a diphosphonic/sulfonic acid resin.

  10. [Assessment of Wiki technology: a tool for accessing information on mechanical ventilation in intensive care].

    PubMed

    Barra, Daniela Couto Carvalho; Dal Sasso, Grace Teresinha Marcon; Martins, Cleusa Rios; Barbosa, Sayonara de Fátima Faria

    2012-01-01

    The development and application of information technology influence all areas of knowledge, enabling new ways of learning. The Wiki is a tool of information and communication technology provided by the Web 2.0 that can be exploited and used in teaching, learning, care and research in nursing education. Thus, this quantitative study is a descriptive and exploratory objective was to evaluate the nursing students with the criteria of Ergonomics and Usability of the tool Wiki as a technology to access information on nursing care in mechanical ventilation in the Intensive Care Unit. The tool was evaluated as "excellent" in the criteria for Ergonomics and Usability, and is considered a new emerging technology suitable for educational use.

  11. Based on asynchronous communication protocol of geographic space information service access mechanism research

    NASA Astrophysics Data System (ADS)

    Chen, G.; Zhao, J.; Gu, M.; Li, D.

    2014-04-01

    At present, the traditional way of accessing to classified network in geographic spatial information services is using network gatekeeper and firewall etc. to ensure public and classified network communications links. However, the physical isolation between classified network and public network is crossed, which is bound to cause classified network potential security hazard. In Yunnan province space Land dynamic monitoring integration project, it proposed the point to point text message communication protocol and asynchronous transmission mechanism. Using geo-spatial information encryption processing and data compression processing method, it reduced the risk of data sensitivity and monitored, namely to ensure data security, which realized geographic spatial information services data communication effectively between classified network and public network in the rigid field conditions.

  12. The need for the use of XACML access control policy in a distributed EHR and some performance considerations.

    PubMed

    Sucurovic, Snezana; Milutinovic, Veljko

    2008-01-01

    The Internet based distributed large scale information systems implements attribute based access control (ABAC) rather than Role Based Access Control (RBAC). The reason is that the Internet is identity less and that ABAC scales better. EXtensible Access Control Markup Language is standardized language for writing access control policies, access control requests and access control responses in ABAC. XACML can provide decentralized administration and credentials distribution. In year 2002 version of CEN ENV 13 606 attributes have been attached to EHCR components and in such a system ABAC and XACML have been easy to implement. This paper presents writing XACML policies in the case when attributes are in hierarchical structure. It is presented two possible solutions to write XACML policy in that case and that the solution when set functions are used is more compact and provides 10% better performances.

  13. Nurse practitioners and controlled substances prescriptive authority: improving access to care.

    PubMed

    Ambrose, Michelle A; Tarlier, Denise S

    2013-03-01

    In 2007, Health Canada proposed a new framework to regulate prescriptive authority for controlled substances, titled New Classes of Practitioners Regulations (NCPR). The new regulatory framework was passed in November 2012; it gives nurse practitioners (NPs), midwives and podiatrists the authority to prescribe controlled medications under the Controlled Drugs and Substances Act. It is expected that authorizing NPs to write prescriptions for certain controlled substances commonly used in primary care will enhance flexibility and timeliness in primary care service delivery. Studies from the United States have shown positive outcomes in primary care access, decreased healthcare costs and the evolution and advancement of the NP role when prescriptive authority was expanded to include controlled substances. The purpose of this paper is to examine how NPs' prescriptive authority for controlled substances affects access to primary care and NP role development. Three key issues identified from the experience of one group of NPs in the United States (access to care, professional autonomy and prescriber knowledge) offer insight into the practice changes that may be anticipated for NPs in Canada now that they have acquired prescriptive authority for controlled substances. Recommendations are offered to assist nurse leaders and educators to best support NPs as they take on this new and important role responsibility.

  14. Prevention and Control of Dental Disease through Improved Access to Comprehensive Care.

    ERIC Educational Resources Information Center

    American Dental Association, Chicago, IL.

    Prevention of dental disease is the key to improving the nation's oral health. The American Dental Association (ADA) program of prevention and control of dental disease through improved access to comprehensive care concentrates on those who have special difficulties in receiving care: the poor, the elderly, the handicapped, the institutionalized…

  15. Secure Access Control and Large Scale Robust Representation for Online Multimedia Event Detection

    PubMed Central

    Liu, Changyu; Li, Huiling

    2014-01-01

    We developed an online multimedia event detection (MED) system. However, there are a secure access control issue and a large scale robust representation issue when we want to integrate traditional event detection algorithms into the online environment. For the first issue, we proposed a tree proxy-based and service-oriented access control (TPSAC) model based on the traditional role based access control model. Verification experiments were conducted on the CloudSim simulation platform, and the results showed that the TPSAC model is suitable for the access control of dynamic online environments. For the second issue, inspired by the object-bank scene descriptor, we proposed a 1000-object-bank (1000OBK) event descriptor. Feature vectors of the 1000OBK were extracted from response pyramids of 1000 generic object detectors which were trained on standard annotated image datasets, such as the ImageNet dataset. A spatial bag of words tiling approach was then adopted to encode these feature vectors for bridging the gap between the objects and events. Furthermore, we performed experiments in the context of event classification on the challenging TRECVID MED 2012 dataset, and the results showed that the robust 1000OBK event descriptor outperforms the state-of-the-art approaches. PMID:25147840

  16. A Model for Trust-based Access Control and Delegation in Mobile Clouds (Post Print)

    DTIC Science & Technology

    2013-10-01

    Qing-Guo, Z., Rong, L.: An Access Control Model for Ubiquitous Computing Application. In: Proceedings of the 2nd International Conference on Mobile ... Technology , Applications and Systems, Guangzhou, China (November 2005) 22. Baracaldo, N., Joshi, J.B.D.: A Trust-and-Risk Aware RBAC Framework: Tackling

  17. Functional requirements with survey results for integrated intrusion detection and access control annunciator systems

    SciTech Connect

    Arakaki, L.H.; Monaco, F.M.

    1995-09-01

    This report contains the guidance Functional Requirements for an Integrated Intrusion Detection and Access Control Annunciator System, and survey results of selected commercial systems. The survey questions were based upon the functional requirements; therefore, the results reflect which and sometimes how the guidance recommendations were met.

  18. The Role of Automatic Indexing in Access Control: A Modular View

    ERIC Educational Resources Information Center

    Hartson, H. Rex

    1974-01-01

    A model which relates the access control and indexing functions. The model is based on concept protection which allows a practically unbounded number of levels (subsets) of protection without requiring a fixed hierarchy among the levels. This protection is offered independently for each of the user operations allowed. (Author)

  19. Predicting Health Care Utilization among Latinos: Health Locus of Control Beliefs or Access Factors?

    ERIC Educational Resources Information Center

    De Jesus, Maria; Xiao, Chenyang

    2014-01-01

    There are two competing research explanations to account for Latinos' underutilization of health services relative to non-Latino Whites in the United States. One hypothesis examines the impact of health locus of control (HLOC) beliefs, while the other focuses on the role of access factors on health care use. To date, the relative strength of…

  20. The Use of Passwords for Controlled Access to Computer Resources. Computer Science & Technology.

    ERIC Educational Resources Information Center

    Wood, Helen M.

    This paper considers the generation of passwords and their effective application to the problem of controlling access to computer resources. After describing the need for and uses of passwords, password schemes are categorized according to selection technique, lifetime, physical characteristics, and information content. Password protection, both…

  1. An Access Control and Trust Management Framework for Loosely-Coupled Multidomain Environments

    ERIC Educational Resources Information Center

    Zhang, Yue

    2010-01-01

    Multidomain environments where multiple organizations interoperate with each other are becoming a reality as can be seen in emerging Internet-based enterprise applications. Access control to ensure secure interoperation in such an environment is a crucial challenge. A multidomain environment can be categorized as "tightly-coupled" and…

  2. 21 CFR 1311.125 - Requirements for establishing logical access control-Individual practitioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... least one of the individuals designated under paragraph (a) of this section must verify that the DEA... authentication credential to satisfy the logical access controls. The second individual must be a DEA registrant... practitioner's DEA registration expires, unless the registration has been renewed. (3) The...

  3. 21 CFR 1311.125 - Requirements for establishing logical access control-Individual practitioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... least one of the individuals designated under paragraph (a) of this section must verify that the DEA... authentication credential to satisfy the logical access controls. The second individual must be a DEA registrant... practitioner's DEA registration expires, unless the registration has been renewed. (3) The...

  4. 21 CFR 1311.125 - Requirements for establishing logical access control-Individual practitioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... least one of the individuals designated under paragraph (a) of this section must verify that the DEA... authentication credential to satisfy the logical access controls. The second individual must be a DEA registrant... practitioner's DEA registration expires, unless the registration has been renewed. (3) The...

  5. 21 CFR 1311.125 - Requirements for establishing logical access control-Individual practitioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... least one of the individuals designated under paragraph (a) of this section must verify that the DEA... authentication credential to satisfy the logical access controls. The second individual must be a DEA registrant... practitioner's DEA registration expires, unless the registration has been renewed. (3) The...

  6. 76 FR 78866 - Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... for Access Control Technologies AGENCY: Copyright Office, Library of Congress. ACTION: Notice of... submitted comments. The Office is taking this action, in part, to clarify the proposal to the best of the... formats; and (2) are legally obtained by blind or other persons with print disabilities (as such...

  7. Mechanically and optically controlled graphene valley filter

    SciTech Connect

    Qi, Fenghua; Jin, Guojun

    2014-05-07

    We theoretically investigate the valley-dependent electronic transport through a graphene monolayer modulated simultaneously by a uniform uniaxial strain and linearly polarized light. Within the Floquet formalism, we calculate the transmission probabilities and conductances of the two valleys. It is found that valley polarization can appear only if the two modulations coexist. Under a proper stretching of the sample, the ratio of the light intensity and the light frequency squared is important. If this quantity is small, the electron transport is mainly contributed by the valley-symmetric central band and the conductance is valley unpolarized; but when this quantity is large, the valley-asymmetric sidebands also take part in the transport and the valley polarization of the conductance appears. Furthermore, the degree of the polarization can be tuned by the strain strength, light intensity, and light frequency. It is proposed that the detection of the valley polarization can be realized utilizing the valley beam splitting. Thus, a graphene monolayer can be used as a mechanically and optically controlled valley filter.

  8. Brain mechanisms that control sleep and waking

    NASA Astrophysics Data System (ADS)

    Siegel, Jerome

    This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep-waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.

  9. Cellular Mechanisms of Ciliary Length Control

    PubMed Central

    Keeling, Jacob; Tsiokas, Leonidas; Maskey, Dipak

    2016-01-01

    Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT) system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia. PMID:26840332

  10. Joint Power and Multiple Access Control for Wireless Mesh Network with Rose Projection Method

    PubMed Central

    Tang, Meiqin; Shang, Lili; Xin, Yalin; Liu, Xiaohua; Wei, Xinjiang

    2014-01-01

    This paper investigates the utility maximization problem for the downlink of the multi-interface multichannel wireless mesh network with orthogonal frequency division multiple access. A cross-layer joint power and multiple access control algorithm are proposed. Rosen projection matrix is combined with Solodov projection techniques to build a three-memory gradient Rosen projection method, which is applied to solve this optimization problem. The convergence analysis is given and simulations show that the proposed solution achieves significant throughput compared with existing approaches. PMID:24883384

  11. Joint power and multiple access control for wireless mesh network with Rose projection method.

    PubMed

    Tang, Meiqin; Shang, Lili; Xin, Yalin; Liu, Xiaohua; Wei, Xinjiang

    2014-01-01

    This paper investigates the utility maximization problem for the downlink of the multi-interface multichannel wireless mesh network with orthogonal frequency division multiple access. A cross-layer joint power and multiple access control algorithm are proposed. Rosen projection matrix is combined with Solodov projection techniques to build a three-memory gradient Rosen projection method, which is applied to solve this optimization problem. The convergence analysis is given and simulations show that the proposed solution achieves significant throughput compared with existing approaches.

  12. Accessibility of dog populations for rabies control in Kathmandu valley, Nepal.

    PubMed Central

    Bögel, K.; Joshi, D. D.

    1990-01-01

    The accessibility of dogs in urban areas of Kathmandu valley was measured using the following approaches: determination of the proportion of dogs that bore signs of having been the objects of religious worship and other signs of household association, supplemented by information obtained by interviewing people in the neighbourhood; and the vaccination coverage attained in a rabies control campaign that was preceded by intensive activities to encourage the community to participate. An accessibility rate of 90-95% was determined using the first of these approaches, whereas 75-80% of the total dog population was reached in the vaccination campaign. PMID:2289296

  13. Expanding the enzyme universe: accessing non-natural reactions by mechanism-guided directed evolution.

    PubMed

    Renata, Hans; Wang, Z Jane; Arnold, Frances H

    2015-03-09

    High selectivity and exquisite control over the outcome of reactions entice chemists to use biocatalysts in organic synthesis. However, many useful reactions are not accessible because they are not in nature's known repertoire. In this Review, we outline an evolutionary approach to engineering enzymes to catalyze reactions not found in nature. We begin with examples of how nature has discovered new catalytic functions and how such evolutionary progression has been recapitulated in the laboratory starting from extant enzymes. We then examine non-native enzyme activities that have been exploited for chemical synthesis, with an emphasis on reactions that do not have natural counterparts. Non-natural activities can be improved by directed evolution, thus mimicking the process used by nature to create new catalysts. Finally, we describe the discovery of non-native catalytic functions that may provide future opportunities for the expansion of the enzyme universe.

  14. Adaptive mechanically controlled lubrication mechanism found in articular joints.

    PubMed

    Greene, George W; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D; Yu, Jing; Israelachvili, Jacob N

    2011-03-29

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions.

  15. Preserving Smart Objects Privacy through Anonymous and Accountable Access Control for a M2M-Enabled Internet of Things.

    PubMed

    Hernández-Ramos, José L; Bernabe, Jorge Bernal; Moreno, M Victoria; Skarmeta, Antonio F

    2015-07-01

    As we get into the Internet of Things era, security and privacy concerns remain as the main obstacles in the development of innovative and valuable services to be exploited by society. Given the Machine-to-Machine (M2M) nature of these emerging scenarios, the application of current privacy-friendly technologies needs to be reconsidered and adapted to be deployed in such global ecosystem. This work proposes different privacy-preserving mechanisms through the application of anonymous credential systems and certificateless public key cryptography. The resulting alternatives are intended to enable an anonymous and accountable access control approach to be deployed on large-scale scenarios, such as Smart Cities. Furthermore, the proposed mechanisms have been deployed on constrained devices, in order to assess their suitability for a secure and privacy-preserving M2M-enabled Internet of Things.

  16. Preserving Smart Objects Privacy through Anonymous and Accountable Access Control for a M2M-Enabled Internet of Things

    PubMed Central

    Hernández-Ramos, José L.; Bernabe, Jorge Bernal; Moreno, M. Victoria; Skarmeta, Antonio F.

    2015-01-01

    As we get into the Internet of Things era, security and privacy concerns remain as the main obstacles in the development of innovative and valuable services to be exploited by society. Given the Machine-to-Machine (M2M) nature of these emerging scenarios, the application of current privacy-friendly technologies needs to be reconsidered and adapted to be deployed in such global ecosystem. This work proposes different privacy-preserving mechanisms through the application of anonymous credential systems and certificateless public key cryptography. The resulting alternatives are intended to enable an anonymous and accountable access control approach to be deployed on large-scale scenarios, such as Smart Cities. Furthermore, the proposed mechanisms have been deployed on constrained devices, in order to assess their suitability for a secure and privacy-preserving M2M-enabled Internet of Things. PMID:26140349

  17. On some control problems in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Abergel, F.; Temam, R.

    The issue of minimizing turbulence in an evolutionary Navier-Stokes flow is addressed from the point of view of optimal control. Theoretical results are derived for various physical situations: distributed control, Benard-type problems with boundary control, and flow in a channel. For each case considered, the results include the formulation of the problem as an optimal control problem and proof of the existence of an optimal control (which is not expected to be unique). Finally, a numerical algorithm based on the gradient method for the corresponding cost function is described.

  18. Distributed joint power and access control algorithm for secondary spectrum sharing

    NASA Astrophysics Data System (ADS)

    Li, Hongyan; Chen, Enqing; Fu, Hongliang

    2010-08-01

    Based on interference temperature model, the problem of efficient secondary spectrum sharing is formulated as a power optimization problem with some constraints at physical layer. These constraints and optimization objective limit a feasible power vector set which leads to the need of access control besides power control. In this paper, we consider the decentralized cognitive radio network scenario where short-term data service is required, and the problem of distributed joint power and access control is studied to maximize the total secondary system throughput, subject to Quality of Service (QoS) constraints from individual secondary users and interference temperature limit (ITL) from primary system. Firstly, a pricing-based game model was used to solve distributed power allocation optimization problem in both high and low signal to interference noise ratio (SINR) scenarios. Secondly, when not all the secondary links can be supported with their QoS requirement and ITL, a distributed joint power and access control algorithm was introduced to find the allowable links which results in maximum network throughput with all the constraints satisfied, and the convergence performance is tested by simulations.

  19. Controlled Unusual Stiffness of Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Lee, Wooju; Kang, Da-Young; Song, Jihwan; Moon, Jun Hyuk; Kim, Dongchoul

    2016-02-01

    Mechanical metamaterials that are engineered with sub-unit structures present unusual mechanical properties depending on the loading direction. Although they show promise, their practical utility has so far been somewhat limited because, to the best of our knowledge, no study about the potential of mechanical metamaterials made from sophisticatedly tailored sub-unit structures has been made. Here, we present a mechanical metamaterial whose mechanical properties can be systematically designed without changing its chemical composition or weight. We study the mechanical properties of triply periodic bicontinuous structures whose detailed sub-unit structure can be precisely fabricated using various sub-micron fabrication methods. Simulation results show that the effective wave velocity of the structures along with different directions can be designed to introduce the anisotropy of stiffness by changing a volume fraction and aspect ratio. The ratio of Young’s modulus to shear modulus can be increased by up to at least 100, which is a 3500% increase over that of isotropic material (2.8, acrylonitrile butadiene styrene). Furthermore, Poisson’s ratio of the constituent material changes the ratio while Young’s modulus does not influence it. This study presents the promising potential of mechanical metamaterials for versatile industrial and biomedical applications.

  20. Finite-time Control of One-link Mechanical System

    NASA Astrophysics Data System (ADS)

    Matoba, Shunsuke; Nakamura, Nami; Nakamura, Hisakazu; Akiba, Hideyuki

    This paper considers finite-time position control of an one-link mechanical system. The system is modeled by discontinuous differential equations. In this paper, we prove that the Nakamura's local homogeneous controller based on a control Lyapunov function is valid to the position control of the robot manipulators, and show the effectiveness of the controller by experiments.

  1. Controlled Access Headings in EAD Finding Aids: Current Practices in Number of and Types of Headings Assigned

    ERIC Educational Resources Information Center

    Mascaro, Michelle

    2011-01-01

    This article presents the findings from a study of controlled access headings assigned to encoded archival description finding aids in the Ohio Library and Information Network Finding Aid Repository, focusing on the number of headings per finding aid and the category of terms assigned. Assigning multiple controlled access headings was widely…

  2. A threat intelligence framework for access control security in the oil industry

    NASA Astrophysics Data System (ADS)

    Alaskandrani, Faisal T.

    The research investigates the problem raised by the rapid development in the technology industry giving security concerns in facilities built by the energy industry containing diverse platforms. The difficulty of continuous updates to network security architecture and assessment gave rise to the need to use threat intelligence frameworks to better assess and address networks security issues. Focusing on access control security to the ICS and SCADA systems that is being utilized to carry out mission critical and life threatening operations. The research evaluates different threat intelligence frameworks that can be implemented in the industry seeking the most suitable and applicable one that address the issue and provide more security measures. The validity of the result is limited to the same environment that was researched as well as the technologies being utilized. The research concludes that it is possible to utilize a Threat Intelligence framework to prioritize security in Access Control Measures in the Oil Industry.

  3. An Internet of Things Example: Classrooms Access Control over Near Field Communication

    PubMed Central

    Palma, Daniel; Agudo, Juan Enrique; Sánchez, Héctor; Macías, Miguel Macías

    2014-01-01

    The Internet of Things is one of the ideas that has become increasingly relevant in recent years. It involves connecting things to the Internet in order to retrieve information from them at any time and from anywhere. In the Internet of Things, sensor networks that exchange information wirelessly via Wi-Fi, Bluetooth, Zigbee or RF are common. In this sense, our paper presents a way in which each classroom control is accessed through Near Field Communication (NFC) and the information is shared via radio frequency. These data are published on the Web and could easily be used for building applications from the data collected. As a result, our application collects information from the classroom to create a control classroom tool that displays access to and the status of all the classrooms graphically and also connects this data with social networks. PMID:24755520

  4. An internet of things example: classrooms access control over near field communication.

    PubMed

    Palma, Daniel; Agudo, Juan Enrique; Sánchez, Héctor; Macías, Miguel Macías

    2014-04-21

    The Internet of Things is one of the ideas that has become increasingly relevant in recent years. It involves connecting things to the Internet in order to retrieve information from them at any time and from anywhere. In the Internet of Things, sensor networks that exchange information wirelessly via Wi-Fi, Bluetooth, Zigbee or RF are common. In this sense, our paper presents a way in which each classroom control is accessed through Near Field Communication (NFC) and the information is shared via radio frequency. These data are published on the Web and could easily be used for building applications from the data collected. As a result, our application collects information from the classroom to create a control classroom tool that displays access to and the status of all the classrooms graphically and also connects this data with social networks.

  5. Sub-Network Access Control Technology Demonstrator: Software Design of the Network Management System

    DTIC Science & Technology

    2002-08-01

    validdes. En d’autres mots, ce projet est une 6tape suppldmentaire dans le dessein de migrer ces technologies radio vers la Flotte Op ~ rationnelle ...Defence Research and Recherche et ddveloppement Development Canada pour la defense Canada DEFENCE • I7 DEFENSE Sub-Network Access Control...dans l’optique qu’ils op ~rent sur des liens avec une large bande passantes dont la topologie 6volue Tentement. Les produites con-nerciaux de gestion de

  6. Control of flexible systems and principles of structural mechanics

    NASA Astrophysics Data System (ADS)

    Oz, H.

    1984-08-01

    Common control approaches for flexible systems are evaluated in regards to their compatibility with the fundamentals of mechanics of structural systems. It is shown that depending on the formulation, control problems may be ill-posed leading to incompatibilities with the basic laws of mechanics. In an effort to eliminate the incompatibilities constructively, it is found that a unique well-posed method of control that is fully in compliance with the fundamentals of structural mechanics exists.

  7. Passive dynamic controllers for nonlinear mechanical systems

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Wu, Shih-Chin; Phan, Minh; Longman, Richard W.

    1991-01-01

    A methodology for model-independant controller design for controlling large angular motion of multi-body dynamic systems is outlined. The controlled system may consist of rigid and flexible components that undergo large rigid body motion and small elastic deformations. Control forces/torques are applied to drive the system and at the same time suppress the vibration due to flexibility of the components. The proposed controller consists of passive second-order systems which may be designed with little knowledge of the system parameter, even if the controlled system is nonlinear. Under rather general assumptions, the passive design assures that the closed loop system has guaranteed stability properties. Unlike positive real controller design, stabilization can be accomplished without direct velocity feedback. In addition, the second-order passive design allows dynamic feedback controllers with considerable freedom to tune for desired system response, and to avoid actuator saturation. After developing the basic mathematical formulation of the design methodology, simulation results are presented to illustrate the proposed approach to a flexible six-degree-of-freedom manipulator.

  8. Computer aided control of a mechanical arm

    NASA Technical Reports Server (NTRS)

    Derocher, W. L., Jr.; Zermuehlen, r. O.

    1979-01-01

    A method for computer-aided remote control of a six-degree-of-freedom manipulator arm involved in the on-orbit servicing of a spacecraft is presented. The control configuration features a supervisory type of control in which each of the segments of a module exchange trajectory is controlled automatically under human supervision, with manual commands to proceed to the next step and in the event of a failure or undesirable outcome. The implementation of the supervisory system is discussed in terms of necessary onboard and ground- or Orbiter-based hardware and software, and a one-g demonstration system built to allow further investigation of system operation is described. Possible applications of the system include the construction of satellite solar power systems, environmental testing and the control of heliostat solar power stations.

  9. A human rights view on access to controlled substances for medical purposes under the international drug control framework.

    PubMed

    Gispen, Marie Elske C

    2013-11-05

    The world is confronted with a major public health deficit caused by poor access to controlled essential medicines under the international drug control framework. This is affecting millions of patients on a daily basis and resulting in numerous human rights violations. The present review contextualises this deficit from a human rights perspective. Drug control efforts are informed by a twofold objective stemming from the double nature of scheduled substances: free access for medical purposes should be ensured, though non-medical use of substances such as opium should be restricted. The international drug control framework is, in theory, based on this twofold notion, however at the level of interpretation, monitoring, and implementation, a one-sided emphasis is demonstrated. By tracing a parallel between the obligations of states under the international drug control framework and those that derive from human rights law, the review shows that the two systems seem incoherent and conflicting in nature and flags the importance of cross-disciplinary research into drug control and human rights.

  10. Critical length scale controls adhesive wear mechanisms

    PubMed Central

    Aghababaei, Ramin; Warner, Derek H.; Molinari, Jean-Francois

    2016-01-01

    The adhesive wear process remains one of the least understood areas of mechanics. While it has long been established that adhesive wear is a direct result of contacting surface asperities, an agreed upon understanding of how contacting asperities lead to wear debris particle has remained elusive. This has restricted adhesive wear prediction to empirical models with limited transferability. Here we show that discrepant observations and predictions of two distinct adhesive wear mechanisms can be reconciled into a unified framework. Using atomistic simulations with model interatomic potentials, we reveal a transition in the asperity wear mechanism when contact junctions fall below a critical length scale. A simple analytic model is formulated to predict the transition in both the simulation results and experiments. This new understanding may help expand use of computer modelling to explore adhesive wear processes and to advance physics-based wear laws without empirical coefficients. PMID:27264270

  11. The mechanical control of nervous system development.

    PubMed

    Franze, Kristian

    2013-08-01

    The development of the nervous system has so far, to a large extent, been considered in the context of biochemistry, molecular biology and genetics. However, there is growing evidence that many biological systems also integrate mechanical information when making decisions during differentiation, growth, proliferation, migration and general function. Based on recent findings, I hypothesize that several steps during nervous system development, including neural progenitor cell differentiation, neuronal migration, axon extension and the folding of the brain, rely on or are even driven by mechanical cues and forces.

  12. Apparatus, method and system to control accessibility of platform resources based on an integrity level

    DOEpatents

    Jenkins, Chris; Pierson, Lyndon G.

    2016-10-25

    Techniques and mechanism to selectively provide resource access to a functional domain of a platform. In an embodiment, the platform includes both a report domain to monitor the functional domain and a policy domain to identify, based on such monitoring, a transition of the functional domain from a first integrity level to a second integrity level. In response to a change in integrity level, the policy domain may configure the enforcement domain to enforce against the functional domain one or more resource accessibility rules corresponding to the second integrity level. In another embodiment, the policy domain automatically initiates operations in aid of transitioning the platform from the second integrity level to a higher integrity level.

  13. [Classical dengue transmission dynamics involving mechanical control and prophylaxis].

    PubMed

    Toro-Zapata, Hernán D; Restrepo, Leonardo D; Vergaño-Salazar, Juan G; Muñoz-Loaiza, Aníbal

    2010-12-01

    Dengue fever transmission dynamics were studied in an endemic region considering the use of preventative measures and mechanical control in reducing transmission of the disease. A system of ordinary differential equations was proposed, describing the dynamics and their evolution as determined by numerical simulation. Different mechanical control and prophylaxis strategies were compared to the situation without control. The basic reproduction number R₀ was determined R₀ to show that if R₀ > 1 there would be a risk of an epidemic and otherwise the disease would have low impact levels. The basic reproduction number helps determine the dynamics' future pattern and contrast the results so obtained with those obtained numerically. It was concluded that although prophylaxis and mechanical control alone provide effective results in controlling the disease, if both controls are combined then infection levels become significantly reduced. Around 60 % mechanical control and prevention levels are needed to provide suitable results in controlling dengue outbreaks.

  14. 11. LAUNCH CONTROL SUPPORT BUILDING. INTERIOR OF MECHANICAL ROOM. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. LAUNCH CONTROL SUPPORT BUILDING. INTERIOR OF MECHANICAL ROOM. VIEW TO SOUTHEAST. - Minuteman III ICBM Launch Control Facility November-1, 1.5 miles North of New Raymer & State Highway 14, New Raymer, Weld County, CO

  15. Mechanisms for leaf control of gas exchange

    SciTech Connect

    Mansfield, T.A.; Davies, W.J.

    1985-03-01

    Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.

  16. Control Engineering Analysis of Mechanical Pitch Systems

    NASA Astrophysics Data System (ADS)

    Bernicke, Olaf; Gauterin, Eckhard; Schulte, Horst; Zajac, Michal

    2014-12-01

    With the help of a local stability analysis the coefficient range of a discrete damper, used for centrifugal forced, mechanical pitch system of small wind turbines (SWT), is gained for equilibrium points. - By a global stability analysis the gained coefficient range can be validated. An appropriate approach by Takagi-Sugeno is presented in the paper.

  17. Manipulator control and mechanization: A telerobot subsystem

    NASA Technical Reports Server (NTRS)

    Hayati, S.; Wilcox, B.

    1987-01-01

    The short- and long-term autonomous robot control activities in the Robotics and Teleoperators Research Group at the Jet Propulsion Laboratory (JPL) are described. This group is one of several involved in robotics and is an integral part of a new NASA robotics initiative called Telerobot program. A description of the architecture, hardware and software, and the research direction in manipulator control is given.

  18. Control and formation mechanism of extended nanochannel geometry in colloidal mesoporous silica particles.

    PubMed

    Sokolov, I; Kalaparthi, V; Volkov, D O; Palantavida, S; Mordvinova, N E; Lebedev, O I; Owens, J

    2017-01-04

    A large class of colloidal multi-micron mesoporous silica particles have well-defined cylindrical nanopores, nanochannels which self-assembled in the templated sol-gel process. These particles are of broad interest in photonics, for timed drug release, enzyme stabilization, separation and filtration technologies, catalysis, etc. Although the pore geometry and mechanism of pore formation of such particles has been widely investigated at the nanoscale, their pore geometry and its formation mechanism at a larger (extended) scale is still under debate. The extended geometry of nanochannels is paramount for all aforementioned applications because it defines accessibility of nanochannels, and subsequently, kinetics of interaction of the nanochannel content with the particle surrounding. Here we present both experimental and theoretical investigation of the extended geometry and its formation mechanism in colloidal multi-micron mesoporous silica particles. We demonstrate that disordered (and consequently, well accessible) nanochannels in the initially formed colloidal particles gradually align and form extended self-sealed channels. This knowledge allows to control the percentage of disordered versus self-sealed nanochannels, which defines accessibility of nanochannels in such particles. We further show that the observed aligning the channels is in agreement with theory; it is thermodynamically favored as it decreases the Gibbs free energy of the particles. Besides the practical use of the obtained results, developing a fundamental understanding of the mechanisms of morphogenesis of complex geometry of nanopores will open doors to efficient and controllable synthesis that will, in turn, further fuel the practical utilization of these particles.

  19. Hypertension Detection, Management, Control and Associated Factors Among Residents Accessing Community Health Services In Beijing

    PubMed Central

    JIANG, Bin; LIU, Hongmei; RU, Xiaojuan; ZHANG, Hui; WU, Shengping; WANG, Wenzhi

    2014-01-01

    The aim of this study was to analyse high blood pressure detection, management, control and associated factors among residents accessing community health services (CHSs) in Beijing. We screened for HBP in 9524 individuals aged 50 years or older who accessed care in four Beijing CHSs. Among the 9397 residents with questionnaire responses that qualified them for inclusion in the study, 5029 patients with HBP were identified, 1510 (i.e., 30% of the HBP patient group) of whom were newly identified cases. The rate of hypertension detection was 53.5%. Among the 5029 HBP patients, the rates of awareness, treatment and control of hypertension were 70.0%, 62.1% and 29.6%, respectively. In general, the rate of hypertension control was higher when the rates of hypertension awareness and treatment were higher in subgroups stratified by different sociodemographic and risk factors, except for the overweight and obesity subgroups. In conclusion, suboptimal HBP awareness, treatment, and control are still major problems confronting CHSs in Beijing. Control of hypertension in the population may be improved by increasing awareness and improving the treatment of hypertension in CHSs. PMID:24784167

  20. Hypertension detection, management, control and associated factors among residents accessing community health services in Beijing.

    PubMed

    Jiang, Bin; Liu, Hongmei; Ru, Xiaojuan; Zhang, Hui; Wu, Shengping; Wang, Wenzhi

    2014-05-02

    The aim of this study was to analyse high blood pressure detection, management, control and associated factors among residents accessing community health services (CHSs) in Beijing. We screened for HBP in 9524 individuals aged 50 years or older who accessed care in four Beijing CHSs. Among the 9397 residents with questionnaire responses that qualified them for inclusion in the study, 5029 patients with HBP were identified, 1510 (i.e., 30% of the HBP patient group) of whom were newly identified cases. The rate of hypertension detection was 53.5%. Among the 5029 HBP patients, the rates of awareness, treatment and control of hypertension were 70.0%, 62.1% and 29.6%, respectively. In general, the rate of hypertension control was higher when the rates of hypertension awareness and treatment were higher in subgroups stratified by different sociodemographic and risk factors, except for the overweight and obesity subgroups. In conclusion, suboptimal HBP awareness, treatment, and control are still major problems confronting CHSs in Beijing. Control of hypertension in the population may be improved by increasing awareness and improving the treatment of hypertension in CHSs.

  1. [Visual attention and its control mechanisms].

    PubMed

    Ogawa, Hirokazu

    2014-04-01

    Given the vast amount of visual information in visual scenes, the capacity of our brain to processes such scenes is severely limited. The core mechanism of selection is referred to as visual attention, and it has been the topic of intense investigation for over 25 years in experimental psychology and cognitive neuroscience. Visual attention is not a single, unitary mechanism, but consists of multiple subcomponents. Attention can be directed to various aspects of visual information, such as spatial location, features, or objects. Additionally, attention is guided by external factors such as the salience of stimuli, or whether we are able to move our attention volitionally. The purpose of this article is to review the status of these components of attentional guidance and how they interact with each other, with an emphasis on psychophysical studies.

  2. Frequency-selective design of wireless power transfer systems for controlled access applications

    NASA Astrophysics Data System (ADS)

    Maschino, Tyler Stephen

    Wireless power transfer (WPT) has become a common way to charge or power many types of devices, ranging from cell phones to electric toothbrushes. WPT became popular through the introduction of a transmission mode known as strongly coupled magnetic resonance (SCMR). This means of transmission is non-radiative and enables mid-range WPT. Shortly after the development of WPT via SCMR, a group of researchers introduced the concept of resonant repeaters, which allows power to hop from the source to the device. These repeaters are in resonance with the WPT system, which enables them to propagate the power wirelessly with minimal losses to the environment. Resonant repeaters have rekindled the dream of ubiquitous wireless power. Inherent risks come with the realization of such a dream. One of the most prominent risks, which we set out in this thesis to address, is that of accessibility to the WPT system. We propose the incorporation of a controlled access schema within a WPT system to prevent unwarranted use of wireless power. Our thesis discusses the history of electromagnetism, examines the inception of WPT via SCMR, evaluates recent developments in WPT, and further elaborates on the controlled access schema we wish to contribute to the field.

  3. An interaction-based access control model (IBAC) for collaborative services

    SciTech Connect

    Altunay, Mine; Byrd, Gregory T.; Brown, Doug E.; Dean, Ralph A.; /North Carolina State U.

    2008-04-01

    A collaboration is a collection of services that work together to achieve a common goal. Although collaborations help when tackling difficult problems, they lead to security issues. First, a collaboration is often performed by services that are drawn from different security domains. Second, a service interacts with multiple peer services during the collaboration. These interactions are not isolated from one another--e.g., data may flow through a sequence of different services. As a result, a service is exposed to multiple peer services in varying degrees, leading to different security threats. We identify the types of interactions that can be present in collaborations, and discuss the security threats due to each type. We propose a model for representing the collaboration context so that a service can be made aware of the existing interactions. We provide an access control model for a service participating in a collaboration. We couple our access control model with a policy model, so that the access requirements from collaborations can be expressed and evaluated.

  4. Autonomous Information Unit for Fine-Grain Data Access Control and Information Protection in a Net-Centric System

    NASA Technical Reports Server (NTRS)

    Chow, Edward T.; Woo, Simon S.; James, Mark; Paloulian, George K.

    2012-01-01

    As communication and networking technologies advance, networks will become highly complex and heterogeneous, interconnecting different network domains. There is a need to provide user authentication and data protection in order to further facilitate critical mission operations, especially in the tactical and mission-critical net-centric networking environment. The Autonomous Information Unit (AIU) technology was designed to provide the fine-grain data access and user control in a net-centric system-testing environment to meet these objectives. The AIU is a fundamental capability designed to enable fine-grain data access and user control in the cross-domain networking environments, where an AIU is composed of the mission data, metadata, and policy. An AIU provides a mechanism to establish trust among deployed AIUs based on recombining shared secrets, authentication and verify users with a username, X.509 certificate, enclave information, and classification level. AIU achieves data protection through (1) splitting data into multiple information pieces using the Shamir's secret sharing algorithm, (2) encrypting each individual information piece using military-grade AES-256 encryption, and (3) randomizing the position of the encrypted data based on the unbiased and memory efficient in-place Fisher-Yates shuffle method. Therefore, it becomes virtually impossible for attackers to compromise data since attackers need to obtain all distributed information as well as the encryption key and the random seeds to properly arrange the data. In addition, since policy can be associated with data in the AIU, different user access and data control strategies can be included. The AIU technology can greatly enhance information assurance and security management in the bandwidth-limited and ad hoc net-centric environments. In addition, AIU technology can be applicable to general complex network domains and applications where distributed user authentication and data protection are

  5. Structural basis of the alternating-access mechanism in a bile acid transporter

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoming; Levin, Elena J.; Pan, Yaping; McCoy, Jason G.; Sharma, Ruchika; Kloss, Brian; Bruni, Renato; Quick, Matthias; Zhou, Ming

    2014-01-01

    Bile acids are synthesized from cholesterol in hepatocytes and secreted through the biliary tract into the small intestine, where they aid in absorption of lipids and fat-soluble vitamins. Through a process known as enterohepatic recirculation, more than 90% of secreted bile acids are then retrieved from the intestine and returned to the liver for resecretion. In humans, there are two Na+-dependent bile acid transporters involved in enterohepatic recirculation, the Na+-taurocholate co-transporting polypeptide (NTCP; also known as SLC10A1) expressed in hepatocytes, and the apical sodium-dependent bile acid transporter (ASBT; also known as SLC10A2) expressed on enterocytes in the terminal ileum. In recent years, ASBT has attracted much interest as a potential drug target for treatment of hypercholesterolaemia, because inhibition of ASBT reduces reabsorption of bile acids, thus increasing bile acid synthesis and consequently cholesterol consumption. However, a lack of three-dimensional structures of bile acid transporters hampers our ability to understand the molecular mechanisms of substrate selectivity and transport, and to interpret the wealth of existing functional data. The crystal structure of an ASBT homologue from Neisseria meningitidis (ASBTNM) in detergent was reported recently, showing the protein in an inward-open conformation bound to two Na+ and a taurocholic acid. However, the structural changes that bring bile acid and Na+ across the membrane are difficult to infer from a single structure. To understand the structural changes associated with the coupled transport of Na+ and bile acids, here we solved two structures of an ASBT homologue from Yersinia frederiksenii (ASBTYf) in a lipid environment, which reveal that a large rigid-body rotation of a substrate-binding domain gives the conserved `crossover' region, where two discontinuous helices cross each other, alternating accessibility from either side of the cell membrane. This result has implications

  6. On the designing of a tamper resistant prescription RFID access control system.

    PubMed

    Safkhani, Masoumeh; Bagheri, Nasour; Naderi, Majid

    2012-12-01

    Recently, Chen et al. have proposed a novel tamper resistant prescription RFID access control system, published in the Journal of Medical Systems. In this paper we consider the security of the proposed protocol and identify some existing weaknesses. The main attack is a reader impersonation attack which allows an active adversary to impersonate a legitimate doctor, e.g. the patient's doctor, to access the patient's tag and change the patient prescription. The presented attack is quite efficient. To impersonate a doctor, the adversary should eavesdrop one session between the doctor and the patient's tag and then she can impersonate the doctor with the success probability of '1'. In addition, we present efficient reader-tag to back-end database impersonation, de-synchronization and traceability attacks against the protocol. Finally, we propose an improved version of protocol which is more efficient compared to the original protocol while provides the desired security against the presented attacks.

  7. Randomized controlled trials in central vascular access devices: A scoping review

    PubMed Central

    Keogh, Samantha; Rickard, Claire M.

    2017-01-01

    Background Randomized controlled trials evaluate the effectiveness of interventions for central venous access devices, however, high complication rates remain. Scoping reviews map the available evidence and demonstrate evidence deficiencies to focus ongoing research priorities. Method A scoping review (January 2006–December 2015) of randomized controlled trials evaluating the effectiveness of interventions to improve central venous access device outcomes; including peripherally inserted central catheters, non-tunneled, tunneled and totally implanted venous access catheters. MeSH terms were used to undertake a systematic search with data extracted by two independent researchers, using a standardized data extraction form. Results In total, 178 trials were included (78 non-tunneled [44%]; 40 peripherally inserted central catheters [22%]; 20 totally implanted [11%]; 12 tunneled [6%]; 6 non-specified [3%]; and 22 combined device trials [12%]). There were 119 trials (68%) involving adult participants only, with 18 (9%) pediatric and 20 (11%) neonatal trials. Insertion-related themes existed in 38% of trials (67 RCTs), 35 RCTs (20%) related to post-insertion patency, with fewer trials on infection prevention (15 RCTs, 8%), education (14RCTs, 8%), and dressing and securement (12 RCTs, 7%). There were 46 different study outcomes reported, with the most common being infection outcomes (161 outcomes; 37%), with divergent definitions used for catheter-related bloodstream and other infections. Conclusion More high quality randomized trials across central venous access device management are necessary, especially in dressing and securement and patency. These can be encouraged by having more studies with multidisciplinary team involvement and consumer engagement. Additionally, there were extensive gaps within population sub-groups, particularly in tunneled devices, and in pediatrics and neonates. Finally, outcome definitions need to be unified for results to be meaningful and

  8. Geometric Computational Mechanics and Optimal Control

    DTIC Science & Technology

    2011-12-02

    methods. Further methods that depend on global optimization problems are in development and preliminary versions of these results, many of which...de la Sociedad Espanola de Matimatica Aplicada (SeMA), 50, 2010, pp 61-81. K. Flaßkamp, S. Ober-Blöbaum, M. Kobilarov, Solving optimal control...continuous setting. Consequently, globally optimal methods for computing optimal trajectories for vehicles with complex dynamics were developed. The

  9. Effects of anesthesia on cardiovascular control mechanisms.

    PubMed Central

    Vatner, S F

    1978-01-01

    The manner in which general anesthesia affects circulatory control was studied by examining the effects of commonly employed anesthetics on left ventricular function and distribution of cardiac output, and the extent to which responses to physiological and pharmacological stimuli are modified by general anesthesia. While commonly employed anesthetics affect almost every aspect of the circulatory system, the importance of general anesthesia on the circulation tends to be underestimated by considering only its direct effects. More important is the modification of the organism's integrative response to any perturbation. Major differences often directionally opposite, in responses of conscious and anesthetized animals were found for reflex control of the circulation, effects of hemorrhage and alterations in preload and after load. In addition, commonly employed pharmacologic agents, e.g., cardiac glycosdies, catecholamines, and morphine sulfate exerted differing actions in the conscious and anesthetized states. Thus, while it is generally held that the overall responses to complex physiological functions such as exercise or eating can be best described in the intact, conscious organism, the importance of conducting any experiment involving integrative control of the circulation in the conscious organism should also be recognized. PMID:363416

  10. Control of Drop Motion by Mechanical Vibrations

    NASA Astrophysics Data System (ADS)

    Bestehorn, Michael

    2014-11-01

    Since the first experimental observations of Michael Faraday in 1831 it is known that a vibrating liquid may show an instability of its flat free surface with respect to oscillating regular surface patterns. We study thin liquid films on a horizontal substrate in the long wave approximation. The films are parametrically excited by mechanical horizontal or inclined oscillations. Inertia effects are taken into account and the standard thin film formulation is extended by a second equation for the vertically averaged mass flux. The films can be additionally unstable by Van der Waals forces on a partially wetting substrate, leading to the formation of drops. These drops can be manipulated by the vibrations to move in a desired direction. Linear results based on a damped complex valued Mathieu equation as well as fully nonlinear results using a reduced model will be presented, for more details see.

  11. An immunosurveillance mechanism controls cancer cell ploidy.

    PubMed

    Senovilla, Laura; Vitale, Ilio; Martins, Isabelle; Tailler, Maximilien; Pailleret, Claire; Michaud, Mickaël; Galluzzi, Lorenzo; Adjemian, Sandy; Kepp, Oliver; Niso-Santano, Mireia; Shen, Shensi; Mariño, Guillermo; Criollo, Alfredo; Boilève, Alice; Job, Bastien; Ladoire, Sylvain; Ghiringhelli, François; Sistigu, Antonella; Yamazaki, Takahiro; Rello-Varona, Santiago; Locher, Clara; Poirier-Colame, Vichnou; Talbot, Monique; Valent, Alexander; Berardinelli, Francesco; Antoccia, Antonio; Ciccosanti, Fabiola; Fimia, Gian Maria; Piacentini, Mauro; Fueyo, Antonio; Messina, Nicole L; Li, Ming; Chan, Christopher J; Sigl, Verena; Pourcher, Guillaume; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Lazar, Vladimir; Penninger, Josef M; Madeo, Frank; López-Otín, Carlos; Smyth, Mark J; Zitvogel, Laurence; Castedo, Maria; Kroemer, Guido

    2012-09-28

    Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers.

  12. Controls on microbial accessibility to soil organic carbon following woody plant encroachment into grasslands

    NASA Astrophysics Data System (ADS)

    Creamer, Courtney; Boutton, Thomas; Olk, Dan; Filley, Timothy

    2010-05-01

    Woody plant encroachment (WPE) into savannas and grasslands is a global phenomenon that alters soil organic carbon (SOC) dynamics through changes in litter quality and quantity, soil structure, microbial ecology, and hydrology. To elucidate the controls on microbial accessibility to SOC, bulk soils from a chronosequence of progressive WPE into native grasslands at the Texas Agrilife La Copita Research Area were incubated for one year. The quantity and stable carbon isotope composition of respired CO2, and plant biopolymer chemistry in SOC were tracked. Respiration rates declined exponentially over the course of the experiment with 15-25% of the total CO2 respired released in the first month of incubation. Between 8 and 18% of the total SOC was mineralized to CO2 throughout the incubation. After day 84 a significantly (p<0.05) greater portion of SOC was mineralized from soils of older woody clusters (34-86 years) than from soils of younger woody clusters (14-23 years) and the native grassland. Invading woody stands of ≃≥35 years of age represent a transition point in WPE where respiration dynamics become distinct in wooded elements compared to grasslands; this distinction has been previously observed through changes in belowground SOC accrual, C input chemistry, and mycorrhizal productivity. Despite documented SOC accrual following WPE at La Copita, we observed no evidence of enhanced SOC stabilization in these respiration experiments. In fact, a greater proportion of total SOC was lost from the soil of mature woody stands than from young stands, suggesting SOC accumulation observed with WPE may be due to greater input rates or microbial dynamics not captured in the laboratory incubation. Compound-specific analyses indicated there was a significant (p<0.05) loss of C from carbohydrates, amino acids, and amino sugars during the incubation. Amino nitrogen tended to become more concentrated during the incubation, although the trend was not significant. Relatively

  13. Experimental Investigation on Transmission Control Protocol Throughput Behavior in Optical Fiber Access Networks

    NASA Astrophysics Data System (ADS)

    Tego, Edion; Matera, Francesco; del Buono, Donato

    2016-03-01

    This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.

  14. A stochastic control approach to Slotted-ALOHA random access protocol

    NASA Astrophysics Data System (ADS)

    Pietrabissa, Antonio

    2013-12-01

    ALOHA random access protocols are distributed protocols based on transmission probabilities, that is, each node decides upon packet transmissions according to a transmission probability value. In the literature, ALOHA protocols are analysed by giving necessary and sufficient conditions for the stability of the queues of the node buffers under a control vector (whose elements are the transmission probabilities assigned to the nodes), given an arrival rate vector (whose elements represent the rates of the packets arriving in the node buffers). The innovation of this work is that, given an arrival rate vector, it computes the optimal control vector by defining and solving a stochastic control problem aimed at maximising the overall transmission efficiency, while keeping a grade of fairness among the nodes. Furthermore, a more general case in which the arrival rate vector changes in time is considered. The increased efficiency of the proposed solution with respect to the standard ALOHA approach is evaluated by means of numerical simulations.

  15. Development and process control of magnetic tunnel junctions for magnetic random access memory devices

    NASA Astrophysics Data System (ADS)

    Kula, Witold; Wolfman, Jerome; Ounadjela, Kamel; Chen, Eugene; Koutny, William

    2003-05-01

    We report on the development and process control of magnetic tunnel junctions (MTJs) for magnetic random access memory (MRAM) devices. It is demonstrated that MTJs with high magnetoresistance ˜40% at 300 mV, resistance-area product (RA) ˜1-3 kΩ μm2, low intrinsic interlayer coupling (Hin) ˜2-3 Oe, and excellent bit switching characteristics can be developed and fully integrated with complementary metal-oxide-semiconductor circuitry into MRAM devices. MTJ uniformity and repeatability level suitable for mass production has been demonstrated with the advanced processing and monitoring techniques.

  16. Neural Control Mechanisms and Body Fluid Homeostasis

    NASA Technical Reports Server (NTRS)

    Johnson, Alan Kim

    1998-01-01

    The goal of the proposed research was to study the nature of afferent signals to the brain that reflect the status of body fluid balance and to investigate the central neural mechanisms that process this information for the activation of response systems which restore body fluid homeostasis. That is, in the face of loss of fluids from intracellular or extracellular fluid compartments, animals seek and ingest water and ionic solutions (particularly Na(+) solutions) to restore the intracellular and extracellular spaces. Over recent years, our laboratory has generated a substantial body of information indicating that: (1) a fall in systemic arterial pressure facilitates the ingestion of rehydrating solutions and (2) that the actions of brain amine systems (e.g., norepinephrine; serotonin) are critical for precise correction of fluid losses. Because both acute and chronic dehydration are associated with physiological stresses, such as exercise and sustained exposure to microgravity, the present research will aid in achieving a better understanding of how vital information is handled by the nervous system for maintenance of the body's fluid matrix which is critical for health and well-being.

  17. Symbiotic Control in Mechanical Bond Formation.

    PubMed

    Wang, Yuping; Sun, Junling; Liu, Zhichang; Nassar, Majed S; Botros, Youssry Y; Stoddart, J Fraser

    2016-09-26

    Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY(.+) units, the radical cationic state of 4,4'-bipyridinium (BIPY(2+) ) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY(.+) radical cations, while the metal itself, which is oxidized to Cu(I) , catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY(.+) radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium.

  18. Rapid Mechanically Controlled Rewiring of Neuronal Circuits

    PubMed Central

    Magdesian, Margaret H.; Lopez-Ayon, G. Monserratt; Mori, Megumi; Boudreau, Dominic; Goulet-Hanssens, Alexis; Sanz, Ricardo; Miyahara, Yoichi; Barrett, Christopher J.; Fournier, Alyson E.; De Koninck, Yves

    2016-01-01

    CNS injury may lead to permanent functional deficits because it is still not possible to regenerate axons over long distances and accurately reconnect them with an appropriate target. Using rat neurons, microtools, and nanotools, we show that new, functional neurites can be created and precisely positioned to directly (re)wire neuronal networks. We show that an adhesive contact made onto an axon or dendrite can be pulled to initiate a new neurite that can be mechanically guided to form new synapses at up to 0.8 mm distance in <1 h. Our findings challenge current understanding of the limits of neuronal growth and have direct implications for the development of new therapies and surgical techniques to achieve functional regeneration. SIGNIFICANCE STATEMENT Brain and spinal cord injury may lead to permanent disability and death because it is still not possible to regenerate neurons over long distances and accurately reconnect them with an appropriate target. Using microtools and nanotools we have developed a new method to rapidly initiate, elongate, and precisely connect new functional neuronal circuits over long distances. The extension rates achieved are ≥60 times faster than previously reported. Our findings have direct implications for the development of new therapies and surgical techniques to achieve functional regeneration after trauma and in neurodegenerative diseases. It also opens the door for the direct wiring of robust brain–machine interfaces as well as for investigations of fundamental aspects of neuronal signal processing and neuronal function. PMID:26791225

  19. Nanoengineering mechanically robust aerogels via control of foam morphology

    NASA Astrophysics Data System (ADS)

    Kucheyev, S. O.; Baumann, T. F.; Cox, C. A.; Wang, Y. M.; Satcher, J. H.; Hamza, A. V.; Bradby, J. E.

    2006-07-01

    Potential of aerogels for technological applications is often limited by their poor mechanical properties. Here, we demonstrate that alumina aerogel monoliths with excellent mechanical properties can be made by controlling the crystallographic phase, shape, and size of nanoligaments. In particular, we show that thermal processing of aerogels with a morphology of interconnected nanoleaflets causes dehydration and associated curling of the nanoleaflets, resulting in a dramatic improvement of mechanical properties. This study shows an effective way to control mechanical properties of the nanoporous solids that can be synthesized with ligaments having a quasi-two-dimensional shape, such as platelets, ribbons, or leaflets.

  20. Face Recognition for Access Control Systems Combining Image-Difference Features Based on a Probabilistic Model

    NASA Astrophysics Data System (ADS)

    Miwa, Shotaro; Kage, Hiroshi; Hirai, Takashi; Sumi, Kazuhiko

    We propose a probabilistic face recognition algorithm for Access Control System(ACS)s. Comparing with existing ACSs using low cost IC-cards, face recognition has advantages in usability and security that it doesn't require people to hold cards over scanners and doesn't accept imposters with authorized cards. Therefore face recognition attracts more interests in security markets than IC-cards. But in security markets where low cost ACSs exist, price competition is important, and there is a limitation on the quality of available cameras and image control. Therefore ACSs using face recognition are required to handle much lower quality images, such as defocused and poor gain-controlled images than high security systems, such as immigration control. To tackle with such image quality problems we developed a face recognition algorithm based on a probabilistic model which combines a variety of image-difference features trained by Real AdaBoost with their prior probability distributions. It enables to evaluate and utilize only reliable features among trained ones during each authentication, and achieve high recognition performance rates. The field evaluation using a pseudo Access Control System installed in our office shows that the proposed system achieves a constant high recognition performance rate independent on face image qualities, that is about four times lower EER (Equal Error Rate) under a variety of image conditions than one without any prior probability distributions. On the other hand using image difference features without any prior probabilities are sensitive to image qualities. We also evaluated PCA, and it has worse, but constant performance rates because of its general optimization on overall data. Comparing with PCA, Real AdaBoost without any prior distribution performs twice better under good image conditions, but degrades to a performance as good as PCA under poor image conditions.

  1. Optimal Tuning for Disturbance Suppression Mechanism for Model Predictive Control

    NASA Astrophysics Data System (ADS)

    Tange, Yoshio; Nakazawa, Chikashi

    Disturbance suppression is one of most required performances in process control. We recently proposed a new disturbance suppression mechanism applicable for model predictive control in order to enhance disturbance suppression performance for ramp-like disturbances. The proposed method utilized the prediction error of controlled values and generates a disturbance compensation signal by a constant gain feedback. In this paper, we propose an improved version of the disturbance suppression mechanism by applying a low-pass filter and parameter tuning methods by which we can make the mechanism more tolerant to various disturbances such as ramp, step, and other supposable ones. We also show numerical simulation results with an oil distillation tower plant.

  2. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications.

    PubMed

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e.

  3. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications

    PubMed Central

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e. PMID:27490666

  4. Temporal control mechanism in equaled interval tapping.

    PubMed

    Yamada, M

    1996-05-01

    Subjects who were at intermediate levels of musical performance made equaled interval tapping in several tempos. The temporal fluctuation for the tapping was observed and analysed. The power spectrum of the fluctuation showed a critical phenomenon at around a frequency which corresponds to the period of 20 taps, for all tempos and all subjects, i.e., the slope of the spectrum was flat or had a positive value in the high frequency region above the critical frequency but it increased as the frequency decreased in the low frequency region below the critical frequency. Moreover, auto-regressive models and Akaike's information criterion were introduced to determine the critical tap number. The order of the best auto-regressive model for the temporal fluctuation data was distributed around 20 taps. These results show that the memory capacity of 20 taps governs the control of equaled interval tapping. To interpret the critical phenomenon of 20 taps with the memory capacity of the short term memory, the so called magic number seven, a simple chunking assumption was introduced; subjects might have unconsciously chunked every three taps during the tapping. If the chunking assumption is true, when subjects consciously chunk every seven taps, the memory capacity of taps should shift to about 50 taps. To test if the assumption is true or not, subjects made a three-beat rhythm tapping and a seven-beat rhythm tapping with equaled intervals. As a result, the memory capacity for these accented tappings were also estimated as 20 taps. This suggests that the critical phenomenon cannot be explained by the chunking assumption and the magic number seven, rather this finding suggests that there exists a memory capacity of 20 taps and this is used for equaled interval tapping.

  5. Security analysis and improvements of authentication and access control in the Internet of Things.

    PubMed

    Ndibanje, Bruce; Lee, Hoon-Jae; Lee, Sang-Gon

    2014-08-13

    Internet of Things is a ubiquitous concept where physical objects are connected over the internet and are provided with unique identifiers to enable their self-identification to other devices and the ability to continuously generate data and transmit it over a network. Hence, the security of the network, data and sensor devices is a paramount concern in the IoT network as it grows very fast in terms of exchanged data and interconnected sensor nodes. This paper analyses the authentication and access control method using in the Internet of Things presented by Jing et al. (Authentication and Access Control in the Internet of Things. In Proceedings of the 2012 32nd International Conference on Distributed Computing Systems Workshops, Macau, China, 18-21 June 2012, pp. 588-592). According to our analysis, Jing et al.'s protocol is costly in the message exchange and the security assessment is not strong enough for such a protocol. Therefore, we propose improvements to the protocol to fill the discovered weakness gaps. The protocol enhancements facilitate many services to the users such as user anonymity, mutual authentication, and secure session key establishment. Finally, the performance and security analysis show that the improved protocol possesses many advantages against popular attacks, and achieves better efficiency at low communication cost.

  6. Security Analysis and Improvements of Authentication and Access Control in the Internet of Things

    PubMed Central

    Ndibanje, Bruce; Lee, Hoon-Jae; Lee, Sang-Gon

    2014-01-01

    Internet of Things is a ubiquitous concept where physical objects are connected over the internet and are provided with unique identifiers to enable their self-identification to other devices and the ability to continuously generate data and transmit it over a network. Hence, the security of the network, data and sensor devices is a paramount concern in the IoT network as it grows very fast in terms of exchanged data and interconnected sensor nodes. This paper analyses the authentication and access control method using in the Internet of Things presented by Jing et al (Authentication and Access Control in the Internet of Things. In Proceedings of the 2012 32nd International Conference on Distributed Computing Systems Workshops, Macau, China, 18–21 June 2012, pp. 588–592). According to our analysis, Jing et al.'s protocol is costly in the message exchange and the security assessment is not strong enough for such a protocol. Therefore, we propose improvements to the protocol to fill the discovered weakness gaps. The protocol enhancements facilitate many services to the users such as user anonymity, mutual authentication, and secure session key establishment. Finally, the performance and security analysis show that the improved protocol possesses many advantages against popular attacks, and achieves better efficiency at low communication cost. PMID:25123464

  7. Heartbeat-driven medium-access control for body sensor networks.

    PubMed

    Li, Huaming; Tan, Jindong

    2010-01-01

    In this paper, a novel time division multiple access based MAC protocol designed for body sensor networks (BSNs) is presented. H-medium-access control (MAC) aims to improve BSNs energy efficiency by exploiting heartbeat rhythm information, instead of using periodic synchronization beacons, to perform time synchronization. Heartbeat rhythm is inherent in every human body and observable in various biosignals. Biosensors in a BSN can extract the heartbeat rhythm from their own sensory data by detecting waveform peaks. All rhythms represented by peak sequences are naturally synchronized since they are driven by the same source, i.e., the heartbeat. Following the rhythm, biosensors can achieve time synchronization without having to turn on their radio to receive periodic timing information from a central controller, so that energy cost for time synchronization can be completely eliminated and the lifetime of the network can be prolonged. An active synchronization recovery scheme is also developed, including two resynchronization approaches. The algorithms are simulated using the discrete event simulator OMNet + + with real-world data from the Massachusetts Institute of Technology-Boston's Beth Israel Hospital multiparameter database Multiparameter Intelligent Monitoring for Intensive Care. The results show that H-MAC can prolong the network life dramatically.

  8. Overview of the Altair Lunar Lander Thermal Control System Design and the Impacts of Global Access

    NASA Technical Reports Server (NTRS)

    Stephan, Ryan A.

    2011-01-01

    NASA's Constellation Program (CxP) was developed to successfully return humans to the Lunar surface prior to 2020. The CxP included several different project offices including Altair, which was planned to be the next generation Lunar Lander. The Altair missions were architected to be quite different than the Lunar missions accomplished during the Apollo era. These differences resulted in a significantly dissimilar Thermal Control System (TCS) design. The current paper will summarize the Altair mission architecture and the various operational phases associated with the planned mission. In addition, the derived thermal requirements and the TCS designed to meet these unique and challenging thermal requirements will be presented. During the past year, the design team has focused on developing a vehicle architecture capable of accessing the entire Lunar surface. Due to the widely varying Lunar thermal environment, this global access requirement resulted in major changes to the thermal control system architecture. These changes, and the rationale behind the changes, will be detailed throughout the current paper.

  9. Analysis of the TDRS multiple access system for possible use as an attitude control system sensor

    NASA Technical Reports Server (NTRS)

    Blevins, Bruce Allyn; Sank, Victor J.

    1993-01-01

    A member of the constellation of TDR satellites (TDRS) has experienced a failure of its prime earth sensor. Failure of the remaining earth sensor could result in the inability of the satellite to control its attitude and provide user services. Loss of the satellite would be a serious event. The multiple access (MA) antenna array on the TDRS has been proposed for use as a backup sensor for the attitude control system. This paper describes our analysis of the performance of the MA array as an interferometer used for accurate attitude determination. A least squares fit of a plane to the MA phase information appears to represent the TDRS body roll and pitch within about 0.1 deg. This is sufficient for SGL pointing and MA and SSA user services. Analytic improvements that include ionospheric correction may yield sufficient accuracy for KSA user services.

  10. Preliminary assessment of Tongue Drive System in medium term usage for computer access and wheelchair control.

    PubMed

    Yousefi, Behnaz; Huo, Xueliang; Ghovanloo, Maysam

    2011-01-01

    Tongue Drive System (TDS) is a wireless, wearable assistive technology that enables individuals with severe motor impairments access computers, drive wheelchairs, and control their environments using tongue motion. In this paper, we have evaluated the TDS performance as a computer input device using ISO9241-9 standard tasks for pointing and selecting, based on the well known Fitts' Law, and as a powered wheelchair controller through an obstacle course navigation task. Nine able-bodied subjects who already had tongue piercing participated in this trial over 5 sessions during 5 weeks, allowing us to study the TDS learning process and its current limiting factors. Subjects worn tongue rings made of titanium in the form of a barbell with a small rare earth magnetic tracer hermetically sealed inside the upper ball. Comparing the results between 1(st) and 5(th) sessions showed that subjects' performance improved in all the measures through 5 sessions, demonstrating the effects of learning.

  11. 17 CFR 240.15c3-5 - Risk management controls for brokers or dealers with market access.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Risk management controls for... Markets § 240.15c3-5 Risk management controls for brokers or dealers with market access. (a) For the... establish, document, and maintain a system of risk management controls and supervisory procedures...

  12. Control of chaos: methods and applications in mechanics.

    PubMed

    Fradkov, Alexander L; Evans, Robin J; Andrievsky, Boris R

    2006-09-15

    A survey of the field related to control of chaotic systems is presented. Several major branches of research that are discussed are feed-forward ('non-feedback') control (based on periodic excitation of the system), the 'Ott-Grebogi-Yorke method' (based on the linearization of the Poincaré map), the 'Pyragas method' (based on a time-delayed feedback), traditional for control-engineering methods including linear, nonlinear and adaptive control. Other areas of research such as control of distributed (spatio-temporal and delayed) systems, chaotic mixing are outlined. Applications to control of chaotic mechanical systems are discussed.

  13. An Analytical Dynamics Approach to the Control of Mechanical Systems

    NASA Astrophysics Data System (ADS)

    Mylapilli, Harshavardhan

    A new and novel approach to the control of nonlinear mechanical systems is presented in this study. The approach is inspired by recent results in analytical dynamics that deal with the theory of constrained motion. The control requirements on the dynamical system are viewed from an analytical dynamics perspective and the theory of constrained motion is used to recast these control requirements as constraints on the dynamical system. Explicit closed form expressions for the generalized nonlinear control forces are obtained by using the fundamental equation of mechanics. The control so obtained is optimal at each instant of time and causes the constraints to be exactly satisfied. No linearizations and/or approximations of the nonlinear dynamical system are made, and no a priori structure is imposed on the nature of nonlinear controller. Three examples dealing with highly nonlinear complex dynamical systems that are chosen from diverse areas of discrete and continuum mechanics are presented to demonstrate the control approach. The first example deals with the energy control of underactuated inhomogeneous nonlinear lattices (or chains), the second example deals with the synchronization of the motion of multiple coupled slave gyros with that of a master gyro, and the final example deals with the control of incompressible hyperelastic rubber-like thin cantilever beams. Numerical simulations accompanying these examples show the ease, simplicity and the efficacy with which the control methodology can be applied and the accuracy with which the desired control objectives can be met.

  14. PANATIKI: a network access control implementation based on PANA for IoT devices.

    PubMed

    Moreno Sanchez, Pedro; Marin Lopez, Rafa; Gomez Skarmeta, Antonio F

    2013-11-01

    Internet of Things (IoT) networks are the pillar of recent novel scenarios, such as smart cities or e-healthcare applications. Among other challenges, these networks cover the deployment and interaction of small devices with constrained capabilities and Internet protocol (IP)-based networking connectivity. These constrained devices usually require connection to the Internet to exchange information (e.g., management or sensing data) or access network services. However, only authenticated and authorized devices can, in general, establish this connection. The so-called authentication, authorization and accounting (AAA) services are in charge of performing these tasks on the Internet. Thus, it is necessary to deploy protocols that allow constrained devices to verify their credentials against AAA infrastructures. The Protocol for Carrying Authentication for Network Access (PANA) has been standardized by the Internet engineering task force (IETF) to carry the Extensible Authentication Protocol (EAP), which provides flexible authentication upon the presence of AAA. To the best of our knowledge, this paper is the first deep study of the feasibility of EAP/PANA for network access control in constrained devices. We provide light-weight versions and implementations of these protocols to fit them into constrained devices. These versions have been designed to reduce the impact in standard specifications. The goal of this work is two-fold: (1) to demonstrate the feasibility of EAP/PANA in IoT devices; (2) to provide the scientific community with the first light-weight interoperable implementation of EAP/PANA for constrained devices in the Contiki operating system (Contiki OS), called PANATIKI. The paper also shows a testbed, simulations and experimental results obtained from real and simulated constrained devices.

  15. PANATIKI: A Network Access Control Implementation Based on PANA for IoT Devices

    PubMed Central

    Sanchez, Pedro Moreno; Lopez, Rafa Marin; Gomez Skarmeta, Antonio F.

    2013-01-01

    Internet of Things (IoT) networks are the pillar of recent novel scenarios, such as smart cities or e-healthcare applications. Among other challenges, these networks cover the deployment and interaction of small devices with constrained capabilities and Internet protocol (IP)-based networking connectivity. These constrained devices usually require connection to the Internet to exchange information (e.g., management or sensing data) or access network services. However, only authenticated and authorized devices can, in general, establish this connection. The so-called authentication, authorization and accounting (AAA) services are in charge of performing these tasks on the Internet. Thus, it is necessary to deploy protocols that allow constrained devices to verify their credentials against AAA infrastructures. The Protocol for Carrying Authentication for Network Access (PANA) has been standardized by the Internet engineering task force (IETF) to carry the Extensible Authentication Protocol (EAP), which provides flexible authentication upon the presence of AAA. To the best of our knowledge, this paper is the first deep study of the feasibility of EAP/PANA for network access control in constrained devices. We provide light-weight versions and implementations of these protocols to fit them into constrained devices. These versions have been designed to reduce the impact in standard specifications. The goal of this work is two-fold: (1) to demonstrate the feasibility of EAP/PANA in IoT devices; (2) to provide the scientific community with the first light-weight interoperable implementation of EAP/PANA for constrained devices in the Contiki operating system (Contiki OS), called PANATIKI. The paper also shows a testbed, simulations and experimental results obtained from real and simulated constrained devices. PMID:24189332

  16. Access Denied

    ERIC Educational Resources Information Center

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  17. A membrane-access mechanism of ion channel inhibition by voltage sensor toxins from spider venom

    NASA Astrophysics Data System (ADS)

    Lee, Seok-Yong; MacKinnon, Roderick

    2004-07-01

    Venomous animals produce small protein toxins that inhibit ion channels with high affinity. In several well-studied cases the inhibitory proteins are water-soluble and bind at a channel's aqueous-exposed extracellular surface. Here we show that a voltage-sensor toxin (VSTX1) from the Chilean Rose Tarantula (Grammostola spatulata) reaches its target by partitioning into the lipid membrane. Lipid membrane partitioning serves two purposes: to localize the toxin in the membrane where the voltage sensor resides and to exploit the free energy of partitioning to achieve apparent high-affinity inhibition. VSTX1, small hydrophobic poisons and anaesthetic molecules reveal a common theme of voltage sensor inhibition through lipid membrane access. The apparent requirement for such access is consistent with the recent proposal that the sensor in voltage-dependent K+ channels is located at the membrane-protein interface.

  18. Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

    PubMed Central

    Razaque, Abdul; Elleithy, Khaled M.

    2014-01-01

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  19. Energy-efficient boarder node medium access control protocol for wireless sensor networks.

    PubMed

    Razaque, Abdul; Elleithy, Khaled M

    2014-03-12

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  20. Quantitative trait loci controlling light and hormone response in two accessions of Arabidopsis thaliana.

    PubMed Central

    Borevitz, Justin O; Maloof, Julin N; Lutes, Jason; Dabi, Tsegaye; Redfern, Joanna L; Trainer, Gabriel T; Werner, Jonathan D; Asami, Tadao; Berry, Charles C; Weigel, Detlef; Chory, Joanne

    2002-01-01

    We have mapped quantitative trait loci (QTL) responsible for natural variation in light and hormone response between the Cape Verde Islands (Cvi) and Landsberg erecta (Ler) accessions of Arabidopsis thaliana using recombinant inbred lines (RILs). Hypocotyl length was measured in four light environments: white, blue, red, and far-red light and in the dark. In addition, white light plus gibberellin (GA) and dark plus the brassinosteroid biosynthesis inhibitor brassinazole (BRZ) were used to detect hormone effects. Twelve QTL were identified that map to loci not previously known to affect light response, as well as loci where candidate genes have been identified from known mutations. Some QTL act in all environments while others show genotype-by-environment interaction. A global threshold was established to identify a significant epistatic interaction between two loci that have few main effects of their own. LIGHT1, a major QTL, has been confirmed in a near isogenic line (NIL) and maps to a new locus with effects in all light environments. The erecta mutation can explain the effect of the HYP2 QTL in the blue, BRZ, and dark environments, but not in far-red. LIGHT2, also confirmed in an NIL, has effects in white and red light and shows interaction with GA. The phenotype and map position of LIGHT2 suggest the photoreceptor PHYB as a candidate gene. Natural variation in light and hormone response thus defines both new genes and known genes that control light response in wild accessions. PMID:11861571

  1. Applying Workspace Limitations in a Velocity-Controlled Robotic Mechanism

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Hargrave, Brian (Inventor); Platt, Robert J., Jr. (Inventor)

    2014-01-01

    A robotic system includes a robotic mechanism responsive to velocity control signals, and a permissible workspace defined by a convex-polygon boundary. A host machine determines a position of a reference point on the mechanism with respect to the boundary, and includes an algorithm for enforcing the boundary by automatically shaping the velocity control signals as a function of the position, thereby providing smooth and unperturbed operation of the mechanism along the edges and corners of the boundary. The algorithm is suited for application with higher speeds and/or external forces. A host machine includes an algorithm for enforcing the boundary by shaping the velocity control signals as a function of the reference point position, and a hardware module for executing the algorithm. A method for enforcing the convex-polygon boundary is also provided that shapes a velocity control signal via a host machine as a function of the reference point position.

  2. [Assessment of exposure to cancerogenic aromatic hydrocarbon during controlled-access highways management activities].

    PubMed

    Martinotti, I; Cirla, A M; Cottica, D; Cirla, P E

    2011-01-01

    The purpose of this study was an integrated assessment of exposure to benzene and Polycyclic Aromatic Hydrocarbons (PAH) in 29 workers employed to manage a controlled-access highways. A campaign was performed in summertime by environmental monitoring (active and passive airborne personal sampler), as well as by biological monitoring (urine samples of the beginning and of the end of daily shift, baseline after two days of vacation). The measured environmental levels did not differ from background environmental concentrations found in a metropolitan area (i.e. benzo[a]pyrene < 1 ng/m3; benzene < 5 mcg/m3), and the results of biological monitoring were in agreement and were compatible with extra-professional habits of the investigated subjects (1-hydroxipyrene 50-990 ng/g creatinine; unmetabolized benzene 15-2010 ng/I; t-t muconic acid < 4-222 mcg/g creatinine).

  3. A time tree medium access control for energy efficiency and collision avoidance in wireless sensor networks.

    PubMed

    Lee, Kilhung

    2010-01-01

    This paper presents a medium access control and scheduling scheme for wireless sensor networks. It uses time trees for sending data from the sensor node to the base station. For an energy efficient operation of the sensor networks in a distributed manner, time trees are built in order to reduce the collision probability and to minimize the total energy required to send data to the base station. A time tree is a data gathering tree where the base station is the root and each sensor node is either a relaying or a leaf node of the tree. Each tree operates in a different time schedule with possibly different activation rates. Through the simulation, the proposed scheme that uses time trees shows better characteristics toward burst traffic than the previous energy and data arrival rate scheme.

  4. Study of Neuro-Controllers for Motion Control Systems with Distributed Mechanical Flexibility.

    DTIC Science & Technology

    2007-11-02

    Control of motion systems involving distributed mechanical flexibility is studied using artificial neural networks . Infinite dimensional nature of...into consideration. Three different neuro controller architectures are studied: 1) Hopfield nets for modal parameter estimation and real time solution of...neural network controller for high precision motion control. Thre results are summarized and details are presented in refereed publications.

  5. The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

    NASA Technical Reports Server (NTRS)

    Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

    1989-01-01

    The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

  6. Thermal Control System Development to Support the Crew Exploration Vehicle and Lunar Surface Access Module

    NASA Technical Reports Server (NTRS)

    Anderson, Molly; Westheimer, David

    2006-01-01

    All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has recently evaluated all of the agency s technology development work and identified key areas that must be addressed to aid in the successful development of a Crew Exploration Vehicle (CEV) and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings.

  7. Mechanisms Underlying Lexical Access in Native and Second Language Processing of Gender and Number Agreement

    ERIC Educational Resources Information Center

    Romanova, Natalia

    2013-01-01

    Despite considerable evidence suggesting that second language (L2) learners experience difficulties when processing morphosyntactic aspects of L2 in online tasks, the mechanisms underlying these difficulties remain unknown. The aim of this dissertation is to explore possible causes for the difficulties by comparing attentional mechanisms engaged…

  8. Study protocol for a cluster-randomised controlled trial of an NCD access to medicines initiative: evaluation of Novartis Access in Kenya

    PubMed Central

    Rockers, Peter C; Wirtz, Veronika J; Vian, Taryn; Onyango, Monica A; Ashigbie, Paul G; Laing, Richard

    2016-01-01

    Introduction Novartis recently launched Novartis Access, an initiative to provide a basket of reduced price medicines for non-communicable diseases (NCDs) to be sold through the public and private non-profit sectors in programme countries. This study will evaluate the impact of Novartis Access on the availability and price of NCD medicines at health facilities and households in Kenya, the first country to receive the programme. Methods and analysis This study will be a cluster-randomised controlled trial. 8 counties in Kenya will be randomly assigned to the intervention or control group using a covariate constrained randomisation method to maximise balance on demographic and health characteristics. In intervention counties, public and private non-profit health facilities will be able to order Novartis Access NCD medicines from the Mission for Essential Drugs and Supplies (MEDS). Data will be collected from a random sample of 384 health facilities and 800 households at baseline, midline after 1-year of intervention, and end-line after 2 years. Quarterly surveillance data will also be collected from health facilities and a subsample of households through phone-based interviews. Households will be eligible if at least one resident has been previously diagnosed and prescribed a medicine for an NCD addressed by Novartis Access, including hypertension and diabetes. The primary outcomes will be availability and price of NCD medicines at health facilities, and availability, price, and expenditures on NCD medicines at households. Impacts will be estimated using intention-to-treat analysis. Ethics and dissemination This protocol was approved by the Institutional Review Boards at Strathmore University and at Boston University. Informed consent will be obtained from all participants at the start of the trial. The findings of the trial will be disseminated through peer-reviewed journals, international conferences, and meetings and events organised with local stakeholders

  9. Pressure versus volume controlled modes in invasive mechanical ventilation.

    PubMed

    Garnero, A J; Abbona, H; Gordo-Vidal, F; Hermosa-Gelbard, C

    2013-05-01

    The first generation of mechanical ventilators were controlled and cycled by pressure. Unfortunately, they did not allow control of the delivered tidal volume under changes in the dynamics of the respiratory system. This led to a second generation of ventilators that allowed volume control, hence favoring the ventilatory strategy based on normalization of the arterial gases. Studies conducted in the 1980s which related lung injury to the high ventilator pressures utilized while treating acute respiratory distress syndrome patients renewed interest in pressure-controlled mechanical ventilation. In addition, new evidence became available, leading to the development of pulmonary protective strategies aiming at preventing the progression of ventilator-induced lung injury. This review provides a detailed description of the control of pressure or volume using certain ventilatory modes, and offers a general view of their advantages and disadvantages, based on the latest available evidence.

  10. Characteristics of Mechanical Pumps and Energy Saving Automatic Control System

    NASA Astrophysics Data System (ADS)

    Ueda, Tadashi; Uchida, Yoshiyuki; Shingu, Hiroyasu

    In the 21st century, global warming has become a very serious ecological problem. It is necessary to prevent global warming from increasing the greenhouse effect gas such as carbon dioxide. A new energy saving technique using mechanical pump system is proposed as a solution to this problem. The pump carrying the water, which is the heat source, for the air conditioner has an effect on energy saving by using effective automatic control. Since there is a lack of knowledge related to mechanical pump, effective automatic control systems combined with some pumps are implemented only in a few buildings. In this paper, the machine characteristics of a mechanical pump and a system design combined with some pumps are applied to a decrease in energy consumption. Based on the characteristics of the pump, the automatic control techniques are constant discharged pressure control technique, estimated end pressure control technique and real end pressure control technique. In this paper, the estimated end pressure control technique is recommended as a result of testing the automatic control system combined with the pumps. Also, improvement in conditions of the pump is proposed as a new energy saving technique.

  11. In Situ Microstructural Control and Mechanical Testing Inside the Transmission Electron Microscope at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Wang, Baoming; Haque, M. A.

    2015-08-01

    With atomic-scale imaging and analytical capabilities such as electron diffraction and energy-loss spectroscopy, the transmission electron microscope has allowed access to the internal microstructure of materials like no other microscopy. It has been mostly a passive or post-mortem analysis tool, but that trend is changing with in situ straining, heating and electrical biasing. In this study, we design and demonstrate a multi-functional microchip that integrates actuators, sensors, heaters and electrodes with freestanding electron transparent specimens. In addition to mechanical testing at elevated temperatures, the chip can actively control microstructures (grain growth and phase change) of the specimen material. Using nano-crystalline aluminum, nickel and zirconium as specimen materials, we demonstrate these novel capabilities inside the microscope. Our approach of active microstructural control and quantitative testing with real-time visualization can influence mechanistic modeling by providing direct and accurate evidence of the fundamental mechanisms behind materials behavior.

  12. Control mechanism of double-rotator-structure ternary optical computer

    NASA Astrophysics Data System (ADS)

    Kai, SONG; Liping, YAN

    2017-03-01

    Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

  13. Growth Control and Disease Mechanisms in Computational Embryogeny

    NASA Technical Reports Server (NTRS)

    Shapiro, Andrew A.; Yogev, Or; Antonsson, Erik K.

    2008-01-01

    This paper presents novel approach to applying growth control and diseases mechanisms in computational embryogeny. Our method, which mimics fundamental processes from biology, enables individuals to reach maturity in a controlled process through a stochastic environment. Three different mechanisms were implemented; disease mechanisms, gene suppression, and thermodynamic balancing. This approach was integrated as part of a structural evolutionary model. The model evolved continuum 3-D structures which support an external load. By using these mechanisms we were able to evolve individuals that reached a fixed size limit through the growth process. The growth process was an integral part of the complete development process. The size of the individuals was determined purely by the evolutionary process where different individuals matured to different sizes. Individuals which evolved with these characteristics have been found to be very robust for supporting a wide range of external loads.

  14. Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.

    PubMed

    Verberne, Berend A; Plümper, Oliver; de Winter, D A Matthijs; Spiers, Christopher J

    2014-12-12

    Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis.

  15. Mechanisms for control of biological electron transfer reactions

    PubMed Central

    Williamson, Heather R.; Dow, Brian A.; Davidson, Victor L.

    2014-01-01

    Electron transfer (ET) through and between proteins is a fundamental biological process. The rates and mechanisms of these ET reactions are controlled by the proteins in which the redox centers that donate and accept electrons reside. The protein influences the magnitudes of the ET parameters, the electronic coupling and reorganization energy that are associated with the ET reaction. The protein can regulate the rates of the ET reaction by requiring reaction steps to optimize the system for ET, leading to kinetic mechanisms of gated or coupled ET. Amino acid residues in the segment of the protein through which long range ET occurs can also modulate the ET rate by serving as staging points for hopping mechanisms of ET. Specific examples are presented to illustrate these mechanisms by which proteins control rates of ET reactions. PMID:25085775

  16. COAXIAL CONTROL ROD DRIVE MECHANISM FOR NEUTRONIC REACTORS

    DOEpatents

    Fox, R.J.; Oakes, L.C.

    1959-04-14

    A drive mechanism is presented for the control rod or a nuclear reactor. In this device the control rod is coupled to a drive shaft which extends coaxially through the rotor of an electric motor for relative rotation with respect thereto. A gear reduction mehanism is coupled between the rotor and the drive shaft to convert the rotary motion of the motor into linear motion of the shaft with a comparatively great reduction in speed, thereby providing relatively glow linear movement of the shaft and control rod for control purposes.

  17. Multisensory Mechanisms of Gaze Stabilization and Flight Control

    DTIC Science & Technology

    2008-12-17

    Multisensory mechanisms of gaze stabilization and flight control 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5d. TASK NUMBER 6. AUTHOR(S...email: h.g.krapp@imperial.ac.uk Imperial College South Kensington Campus London SW7 2AZ “ Multisensory Mechanisms of Gaze... Multisensory Integration, and Efference Copies in Behaving Animals 2.5 State-dependent Processing in LPTCs 2.6 Characterization of Head Movements in the

  18. Payment mechanisms and the composition of physician practices: balancing cost-containment, access, and quality of care.

    PubMed

    Barham, Victoria; Milliken, Olga

    2015-07-01

    We take explicit account of the way in which the supply of physicians and patients in the economy affects the design of physician remuneration schemes, highlighting the three-way trade-off between quality of care, access, and cost. Both physicians and patients are heterogeneous. Physicians choose both the number of patients and the quality of care to provide to their patients. When determining physician payment rates, the principal must ensure access to care for all patients. When physicians can adjust the number of patients seen, there is no incentive to over-treat. In contrast, altruistic physicians always quality stint: they prefer to add an additional patient, rather than to increase the quality of service provided. A mixed payment mechanism does not increase the quality of service provided with respect to capitation. Offering a menu of compensation schemes may constitute a cost-effective strategy for inducing physicians to choose a given overall caseload but may also generate difficulties with access to care for frail patients.

  19. Controlling multidrug-resistant tuberculosis and access to expensive drugs: a rational framework.

    PubMed Central

    Pablos-Mendez, Ariel; Gowda, Deepthiman K.; Frieden, Thomas R.

    2002-01-01

    The emergence and spread of multidrug-resistant tuberculosis (MDR-TB), i.e. involving resistance to at least isoniazid and rifampicin, could threaten the control of TB globally. Controversy has emerged about the best way of confronting MDR-TB in settings with very limited resources. In 1999, the World Health Organization (WHO) created a working group on DOTS-Plus, an initiative exploring the programmatic feasibility and cost-effectiveness of treating MDR-TB in low-income and middle-income countries, in order to consider the management of MDR-TB under programme conditions. The challenges of implementation have proved more daunting than those of access to second-line drugs, the prices of which are dropping. Using data from the WHO/International Union Against Tuberculosis and Lung Disease surveillance project, we have grouped countries according to the proportion of TB patients completing treatment successfully and the level of MDR-TB among previously untreated patients. The resulting matrix provides a reasonable framework for deciding whether to use second-line drugs in a national programme. Countries in which the treatment success rate, i.e. the proportion of new patients who complete the scheduled treatment, irrespective of whether bacteriological cure is documented, is below 70% should give the highest priority to introducing or improving DOTS, the five-point TB control strategy recommended by WHO and the International Union Against Tuberculosis and Lung Disease. A poorly functioning programme can create MDR-TB much faster than it can be treated, even if unlimited resources are available. There is no single prescription for controlling MDR-TB but the various tools available should be applied wisely. Firstly, good DOTS and infection control; then appropriate use of second-line drug treatment. The interval between the two depends on the local context and resources. As funds are allocated to treat MDR-TB, human and financial resources should be increased to expand

  20. Mechanically implementable accommodation matrices for passive force control

    SciTech Connect

    Goswami, A.; Peshkin, M.

    1999-08-01

    Robot force control implemented by means of passive mechanical devices has inherent advantages over active implementations with regard to stability, response rapidity, and physical robustness. The class of devices considered in this paper consists of a Stewart platform-type mechanism interconnected with a network of adjustable mechanical elements such as springs and dampers. The control law repertoire of such a device, imagined as a robot wrist, is given by the range of admittance matrices that it may be programmed to possess. This paper focuses on wrists incorporating damper networks for which the admittance matrices reduce to accommodation or inverse-damping matrices. The authors show that a hydraulic network of fully adjustable damper elements may attain any diagonally dominant accommodation matrix. They describe the technique of selecting the individual damping coefficients to design a desired matrix. They identify the set of dominant matrices as a polyhedral convex cone in the space of matrix entries, and show that each dominant matrix can be composed of a positive linear combination of a fixed set of basis matrices. The overall wrist-accommodation matrix is obtained by projecting the accommodation matrix of the damper network through the wrist kinematics. The linear combination of the dominant basis matrices projected through the wrist kinematics generates the entire space of mechanically implementable force-control laws. The authors quantify the versatility of mechanically implementable force-control laws by comparing this space to the space of all matrices.

  1. A low power medium access control protocol for wireless medical sensor networks.

    PubMed

    Lamprinos, I; Prentza, A; Sakka, E; Koutsouris, D

    2004-01-01

    The concept of a wireless integrated network of sensors, already applied in several sectors of our everyday life, such as security, transportation and environment monitoring, can as well provide an advanced monitor and control resource for healthcare services. By networking medical sensors wirelessly, attaching them in patient's body, we create the appropriate infrastructure for continuous and real-time monitoring of patient without discomforting him. This infrastructure can improve healthcare by providing the means for flexible acquisition of vital signs, while at the same time it provides more convenience to the patient. Given the type of wireless network, traditional medium access control (MAC) protocols cannot take advantage of the application specific requirements and information characteristics occurring in medical sensor networks, such as the demand for low power consumption and the rather limited and asymmetric data traffic. In this paper, we present the architecture of a low power MAC protocol, designated to support wireless networks of medical sensors. This protocol aims to improve energy efficiency by exploiting the inherent application features and requirements. It is oriented towards the avoidance of main energy wastage sources, such as idle listening, collision and power outspending.

  2. Analyzing the effect of routing protocols on media access control protocols in radio networks

    SciTech Connect

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

    2002-01-01

    We study the effect of routing protocols on the performance of media access control (MAC) protocols in wireless radio networks. Three well known MAC protocols: 802.11, CSMA, and MACA are considered. Similarly three recently proposed routing protocols: AODV, DSR and LAR scheme 1 are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of our experiments was to study how the routing protocols affect the performance of the MAC protocols when the underlying network and traffic parameters are varied. The performance of the protocols was measured w.r.t. five important parameters: (i) number of received packets, (ii) average latency of each packet, (iii) throughput (iv) long term fairness and (v) number of control packets at the MAC layer level. Our results show that combinations of routing and MAC protocols yield varying performance under varying network topology and traffic situations. The result has an important implication; no combination of routing protocol and MAC protocol is the best over all situations. Also, the performance analysis of protocols at a given level in the protocol stack needs to be studied not locally in isolation but as a part of the complete protocol stack. A novel aspect of our work is the use of statistical technique, ANOVA (Analysis of Variance) to characterize the effect of routing protocols on MAC protocols. This technique is of independent interest and can be utilized in several other simulation and empirical studies.

  3. mHealth: A Mechanism to Deliver More Accessible, More Effective Mental Health Care

    PubMed Central

    Price, Matthew; Yuen, Erica K.; Goetter, Elizabeth M.; Herbert, James D.; Forman, Evan M.; Acierno, Ron; Ruggiero, Kenneth J.

    2013-01-01

    The increased popularity and functionality of mobile devices has a number of implications for the delivery of mental health services. Effective use of mobile applications has the potential to (a) increase access to evidence-based care; (b) better inform consumers of care and more actively engage them in treatment; (c) increase the use of evidence-based practices; and (d) enhance care after formal treatment has concluded. The current paper presents an overview of the many potential uses of mobile applications as a means to facilitate ongoing care at various stages of treatment. Examples of current mobile applications in behavioural treatment and research are described, and the implications of such uses are discussed. Finally, we provide recommendations for methods to include mobile applications into current treatment and outline future directions for evaluation. PMID:23918764

  4. Mechanical Response of DNA–Nanoparticle Crystals to Controlled Deformation

    PubMed Central

    2016-01-01

    The self-assembly of DNA-conjugated nanoparticles represents a promising avenue toward the design of engineered hierarchical materials. By using DNA to encode nanoscale interactions, macroscale crystals can be formed with mechanical properties that can, at least in principle, be tuned. Here we present in silico evidence that the mechanical response of these assemblies can indeed be controlled, and that subtle modifications of the linking DNA sequences can change the Young’s modulus from 97 kPa to 2.1 MPa. We rely on a detailed molecular model to quantify the energetics of DNA–nanoparticle assembly and demonstrate that the mechanical response is governed by entropic, rather than enthalpic, contributions and that the response of the entire network can be estimated from the elastic properties of an individual nanoparticle. The results here provide a first step toward the mechanical characterization of DNA–nanoparticle assemblies, and suggest the possibility of mechanical metamaterials constructed using DNA. PMID:27725959

  5. Active Control of Mixing and Combustion, from Mechanisms to Implementation

    NASA Astrophysics Data System (ADS)

    Ghoniem, Ahmed F.

    2001-11-01

    Implementation of active control in complex processes, of the type encountered in high Reynolds number mixing and combustion, is predicated upon the identification of the underlying mechanisms and the construction of reduced order models that capture their essential characteristics. The mechanisms of interest must be shown to be amenable to external actuations, allowing optimal control strategies to exploit the delicate interactions that lead to the desired outcome. Reduced order models are utilized in defining the form and requisite attributes of actuation, its relationship to the monitoring system and the relevant control algorithms embedded in a feedforward or a feedback loop. The talk will review recent work on active control of mixing in combustion devices in which strong shear zones concur with mixing, combustion stabilization and flame anchoring. The underlying mechanisms, e.g., stability of shear flows, formation/evolution of large vortical structures in separating and swirling flows, their mutual interactions with acoustic fields, flame fronts and chemical kinetics, etc., are discussed in light of their key roles in mixing, burning enhancement/suppression, and combustion instability. Subtle attributes of combustion mechanisms are used to suggest the requisite control strategies.

  6. Output feedback control of a mechanical system using magnetic levitation.

    PubMed

    Beltran-Carbajal, F; Valderrabano-Gonzalez, A; Rosas-Caro, J C; Favela-Contreras, A

    2015-07-01

    This paper presents an application of a nonlinear magnetic levitation system to the problem of efficient active control of mass-spring-damper mechanical systems. An output feedback control scheme is proposed for reference position trajectory tracking tasks on the flexible mechanical system. The electromagnetically actuated system is shown to be a differentially flat nonlinear system. An extended state estimation approach is also proposed to obtain estimates of velocity, acceleration and disturbance signals. The differential flatness structural property of the system is then employed for the synthesis of the controller and the signal estimation approach presented in this work. Some experimental and simulation results are included to show the efficient performance of the control approach and the effective estimation of the unknown signals.

  7. Design and control of a high precision drive mechanism

    NASA Astrophysics Data System (ADS)

    Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

    2017-01-01

    This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

  8. Designing Crane Controls with applied Mechanical and Electrical Safety Features

    NASA Technical Reports Server (NTRS)

    Lytle, Bradford P.; Walczak, Thomas A.; Delgado, H. (Technical Monitor)

    2002-01-01

    The use of overhead traveling bridge cranes in many varied applications is common practice. In particular, the use of cranes in the nuclear, military, commercial, aerospace, and other industries can involve safety critical situations. Considerations for Human Injury or Casualty, Loss of Assets, Endangering the Environment, or Economic Reduction must be addressed. Traditionally, in order to achieve additional safety in these applications, mechanical systems have been augmented with a variety of devices. These devices assure that a mechanical component failure shall reduce the risk of a catastrophic loss of the correct and/or safe load carrying capability. ASME NOG-1-1998, (Rules for Construction of Overhead and Gantry Cranes, Top Running Bridge, and Multiple Girder), provides design standards for cranes in safety critical areas. Over and above the minimum safety requirements of todays design standards, users struggle with obtaining a higher degree of reliability through more precise functional specifications while attempting to provide "smart" safety systems. Electrical control systems also may be equipped with protective devices similar to the mechanical design features. Demands for improvement of the cranes "control system" is often recognized, but difficult to quantify for this traditionally "mechanically" oriented market. Finite details for each operation must be examined and understood. As an example, load drift (or small motions) at close tolerances can be unacceptable (and considered critical). To meet these high functional demands encoders and other devices are independently added to control systems to provide motion and velocity feedback to the control drive. This paper will examine the implementation of Programmable Electronic Systems (PES). PES is a term this paper will use to describe any control system utilizing any programmable electronic device such as Programmable Logic Controllers (PLC), or an Adjustable Frequency Drive (AID) 'smart' programmable

  9. Control Mechanism Strategies for Spin-Stabilized Projectiles

    DTIC Science & Technology

    2008-09-01

    maneuver footprint shape was dictated by the angle -of-fall and yaw of repose . Shallow angles -of-fall produced footprint ellipses, with a major axis...Magnus moments and yaw of repose . Adding a control mechanism such as fins to guide a spin- stabilized projectile further complicates the resulting...ratio), and the roll window over which the pulsed controller operated. The metrics of this analysis were the maneuver footprint, total angle of attack

  10. Mechanisms of active control for noise inside a vibrating cylinder

    NASA Technical Reports Server (NTRS)

    Lester, Harold C.; Fuller, Chris R.

    1987-01-01

    The active control of propeller-induced noise fields inside a flexible cylinder is studied with attention given to the noise reduction mechanisms inherent in the present coupled acoustic shell model. The active noise control model consists of an infinitely long aluminum cylinder with a radius of 0.4 m and a thickness of 0.001 m. Pressure maps are shown when the two external sources are driven in-phase at a frequency corresponding to Omega = 0.22.

  11. Capacity allocation mechanism based on differentiated QoS in 60 GHz radio-over-fiber local access network

    NASA Astrophysics Data System (ADS)

    Kou, Yanbin; Liu, Siming; Zhang, Weiheng; Shen, Guansheng; Tian, Huiping

    2017-03-01

    We present a dynamic capacity allocation mechanism based on the Quality of Service (QoS) for different mobile users (MU) in 60 GHz radio-over-fiber (RoF) local access networks. The proposed mechanism is capable for collecting the request information of MUs to build a full list of MU capacity demands and service types at the Central Office (CO). A hybrid algorithm is introduced to implement the capacity allocation which can satisfy the requirements of different MUs at different network traffic loads. Compared with the weight dynamic frames assignment (WDFA) scheme, the Hybrid scheme can keep high priority MUs in low delay and maintain the packet loss rate less than 1% simultaneously. At the same time, low priority MUs have a relatively better performance.

  12. The IEO Data Center Management System: Tools for quality control, analysis and access marine data

    NASA Astrophysics Data System (ADS)

    Casas, Antonia; Garcia, Maria Jesus; Nikouline, Andrei

    2010-05-01

    Since 1994 the Data Centre of the Spanish Oceanographic Institute develops system for archiving and quality control of oceanographic data. The work started in the frame of the European Marine Science & Technology Programme (MAST) when a consortium of several Mediterranean Data Centres began to work on the MEDATLAS project. Along the years, old software modules for MS DOS were rewritten, improved and migrated to Windows environment. Oceanographic data quality control includes now not only vertical profiles (mainly CTD and bottles observations) but also time series of currents and sea level observations. New powerful routines for analysis and for graphic visualization were added. Data presented originally in ASCII format were organized recently in an open source MySQL database. Nowadays, the IEO, as part of SeaDataNet Infrastructure, has designed and developed a new information system, consistent with the ISO 19115 and SeaDataNet standards, in order to manage the large and diverse marine data and information originated in Spain by different sources, and to interoperate with SeaDataNet. The system works with data stored in ASCII files (MEDATLAS, ODV) as well as data stored within the relational database. The components of the system are: 1.MEDATLAS Format and Quality Control - QCDAMAR: Quality Control of Marine Data. Main set of tools for working with data presented as text files. Includes extended quality control (searching for duplicated cruises and profiles, checking date, position, ship velocity, constant profiles, spikes, density inversion, sounding, acceptable data, impossible regional values,...) and input/output filters. - QCMareas: A set of procedures for the quality control of tide gauge data according to standard international Sea Level Observing System. These procedures include checking for unexpected anomalies in the time series, interpolation, filtering, computation of basic statistics and residuals. 2. DAMAR: A relational data base (MySql) designed to

  13. Estradiol as a mechanism for sex differences in the development of an addicted phenotype following extended access cocaine self-administration.

    PubMed

    Ramôa, Carolina P; Doyle, Susan E; Naim, Diana W; Lynch, Wendy J

    2013-08-01

    Women progress more rapidly after initial cocaine use to addiction as compared with men. Similarly, female rats appear to require less cocaine exposure before developing an addicted phenotype with evidence implicating estradiol as a potential mechanism. The goals of this study were to determine whether there are sex differences in the magnitude of the addicted phenotype under optimized conditions that induce its development in both males and females and to determine the role of estradiol in this effect. Following acquisition, intact male and intact and ovariectomized (OVX) female rats with and without estradiol replacement were given access to cocaine (1.5 mg/kg per infusion) under either extended access (ExA; discrete trial procedure, 4 trials/h, 24 h/day, 10 days) or short access (ShA) conditions (20 infusions maximum/day, 3 days). Motivation to obtain cocaine (0.5 mg/kg/infusion), as assessed under a progressive-ratio schedule, was then examined following a 2-week abstinence period. Results showed that following ExA self-administration, both males and females developed an addicted phenotype, with 9 of 11 males and 8 of 10 females showing a greater than 15% increase in levels of motivation to obtain cocaine as compared with ShA controls. In contrast, within the OVX groups, responding was enhanced from control levels after ExA self-administration in estradiol-replaced rats only. These results suggest that while females may have an enhanced vulnerability to developing an addicted phenotype, they may be similar to males once addiction has developed. These results also suggest that estradiol is critically involved in the development of an addicted phenotype in females.

  14. Estradiol as a Mechanism for Sex Differences in the Development of an Addicted Phenotype following Extended Access Cocaine Self-Administration

    PubMed Central

    Ramôa, Carolina P; Doyle, Susan E; Naim, Diana W; Lynch, Wendy J

    2013-01-01

    Women progress more rapidly after initial cocaine use to addiction as compared with men. Similarly, female rats appear to require less cocaine exposure before developing an addicted phenotype with evidence implicating estradiol as a potential mechanism. The goals of this study were to determine whether there are sex differences in the magnitude of the addicted phenotype under optimized conditions that induce its development in both males and females and to determine the role of estradiol in this effect. Following acquisition, intact male and intact and ovariectomized (OVX) female rats with and without estradiol replacement were given access to cocaine (1.5 mg/kg per infusion) under either extended access (ExA; discrete trial procedure, 4 trials/h, 24 h/day, 10 days) or short access (ShA) conditions (20 infusions maximum/day, 3 days). Motivation to obtain cocaine (0.5 mg/kg/infusion), as assessed under a progressive-ratio schedule, was then examined following a 2-week abstinence period. Results showed that following ExA self-administration, both males and females developed an addicted phenotype, with 9 of 11 males and 8 of 10 females showing a greater than 15% increase in levels of motivation to obtain cocaine as compared with ShA controls. In contrast, within the OVX groups, responding was enhanced from control levels after ExA self-administration in estradiol-replaced rats only. These results suggest that while females may have an enhanced vulnerability to developing an addicted phenotype, they may be similar to males once addiction has developed. These results also suggest that estradiol is critically involved in the development of an addicted phenotype in females. PMID:23481437

  15. Fluid Mechanics of Wing Adaptation for Separation Control

    NASA Technical Reports Server (NTRS)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  16. Quality Control Mechanisms for Appraising the Teaching Labour Force.

    ERIC Educational Resources Information Center

    Tam, Peter Tim-Kui

    1992-01-01

    To maintain teacher quality, the use of assessment mechanisms and instruments are necessary. Suggests a general teacher evaluation framework ranging from preservice teacher education through professional development and peer-controlled certification. Argues that valid, fair, and reliable methods of teacher evaluation require adequate financial…

  17. Three degree of freedom translational axis hand controller mechanism

    NASA Technical Reports Server (NTRS)

    Menahem, Israel (Inventor); Bacon, James (Inventor)

    1993-01-01

    A hand controller which includes a hand grip having therein a mechanism for allowing truly linear motion along at least two axes by modifying a four-bar linkage with a second four-bar linkage to counteract any rotational motion that would otherwise occur.

  18. Quasivelocities and Optimal Control for underactuated Mechanical Systems

    NASA Astrophysics Data System (ADS)

    Colombo, L.; de Diego, D. Martín

    2010-07-01

    This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

  19. 6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ACCUMULATOR TANK WHICH STORE AIR PRESSURE TO OPEN GATES AND GET GENERATOR STARTED. LARGE TANK AT RIGHT IS THE MAIN GUARD VALVE FOR THE GENERATOR - Los Angeles Aqueduct, Haiwee Power Plant, Los Angeles, Los Angeles County, CA

  20. Control of mechanical systems with rolling contacts: Applications to robotics

    NASA Astrophysics Data System (ADS)

    Sarkar, Nilanjan

    1993-01-01

    The problems of modeling and control of mechanical dynamic systems subject to rolling contacts are investigated. There are two important theoretical contributions in this dissertation. First, contact kinematic relationships up to second order are developed for two rigid bodies in point contact. These equations relate gross rigid body motion to the changes in the positions of the points of contact. Second, a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints is proposed. The basic approach is to extend the state-space to include, in the addition to the generalized coordinates and velocities, contact coordinates which describe the displacements of the contact points and their derivatives. This redundant state-space formulation provides a convenient way to specify output equations to control contact motion. The control problem is formulated as an affine nonlinear problem and a differential-geometric, control-theoretic approach is used to decouple and linearize such systems. It is shown that such a system, even though not input-state linearizable, is input-output linearizable. Further, the zero dynamics of such a system is shown to be Lagrange stable. The proposed methodology is applied to three different robotic systems: (1) wheeled mobile robots; (2) two arms manipulating an object with rolling contact between each arm and the object; and (3) a single robot arm maintaining controlled contact against a moving environment. In each case, a nonlinear controller is designed to achieve the desired performances. For mobile robots, a new control algorithm called dynamic path following is proposed and shown to be quite effective and robust. In the context of two arm manipulation, grasp adaptation through the control of contact motion is demonstrated. Maintaining rolling contact with a moving surface is formulated as an acatastatic system. The proposed scheme involves simultaneously controlling interaction forces as

  1. Mechanisms and Control of Silk-based Electrospinning

    PubMed Central

    Zhang, Feng; Zuo, Baoqi; Fan, Zhihai; Xie, Zonggang; Lu, Qiang; Zhang, Xueguang; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) nanofibers, formed through electrospinning, have attractive utility in regenerative medicine due to the biocompatibility, mechanical properties and tailorable degradability. The mechanism of SF electrospun nanofiber formation was studied to gain new insight into the formation and control of nanofibers. SF electrospinning solutions with different nanostructures (nanospheres or nanofilaments) were prepared by controlling the drying process during the preparation of regenerated SF films. Compared to SF nanospheres in solution, SF nanofilaments had better spinnability with lower viscosity when the concentration of silk protein was below 10%, indicating a critical role for SF morphology, and in particular, nanostructures for the formation of electrospun fibers. More interesting, the diameter of electrospun fibers gradually increased from 50 nm to 300 nm as the increase in concentration of SF nanofilaments in the solution from 6% to 12%, implying size control by simply adjusting SF nanostructure and concentration. Aside from process parameters investigated in previous studies, such as SF concentration, viscosity and electrical potential, the present mechanism emphasizes significant influence of SF nanostructure on spinnability and diameter control of SF electrospun fibers, providing a controllable option for the preparation of silk-based electrospun scaffolds for biomaterials, drug delivery and tissue engineering needs. PMID:22300335

  2. Active vibration control using mechanical and electrical analogies

    NASA Astrophysics Data System (ADS)

    Torres-Perez, A.; Hassan, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

  3. Robust control of multi-jointed arm with a decentralized autonomous control mechanism

    NASA Technical Reports Server (NTRS)

    Kimura, Shinichi; Miyazaki, Ken; Suzuki, Yoshiaki

    1994-01-01

    A decentralized autonomous control mechanism applied to the control of three dimensional manipulators and its robustness to partial damage was assessed by computer simulation. Decentralized control structures are believed to be quite robust to time delay between the operator and the target system. A 10-jointed manipulator based on our control mechanism was able to continue its positioning task in three-dimensional space without revision of the control program, even after some of its joints were damaged. These results suggest that this control mechanism can be effectively applied to space telerobots, which are associated with serious time delay between the operator and the target system, and which cannot be easily repaired after being partially damaged.

  4. Mechanisms in environmentally assisted one-photon phase control

    NASA Astrophysics Data System (ADS)

    Pachón, Leonardo A.; Brumer, Paul

    2013-10-01

    The ability of an environment to assist in one-photon phase control relies upon entanglement between the system and bath and on the breaking of the time reversal symmetry. Here, one-photon phase control is examined analytically and numerically in a model system, allowing an analysis of the relative strength of these contributions. Further, the significant role of non-Markovian dynamics and of moderate system-bath coupling in enhancing one-photon phase control is demonstrated, and an explicit role for quantum mechanics is noted in the existence of initial non-zero stationary coherences. Finally, desirable conditions are shown to be required to observe such environmentally assisted control, since the system will naturally equilibrate with its environment at longer times, ultimately resulting in the loss of phase control.

  5. Control of autoresonance in mechanical and physical models

    NASA Astrophysics Data System (ADS)

    Kovaleva, A.

    2017-03-01

    Autoresonant energy transfer has been considered as one of the most effective methods of excitation and control of high-energy oscillations for a broad range of physical and engineering systems. Nonlinear time-invariant feedback control provides effective self-tuning and self-adaptation mechanisms targeted at preserving resonance oscillations under variations of the system parameters but its implementation may become extremely complicated. A large class of systems can avoid nonlinear feedback, still producing the required state due to time-variant feed-forward frequency control. This type of control in oscillator arrays employs an intrinsic property of a nonlinear oscillator to vary both its amplitude and the frequency when the driving frequency changes. This paper presents a survey of recently published and new results studying possibilities and limitations of time-variant frequency control in nonlinear oscillator arrays. This article is part of the themed issue 'Horizons of cybernetical physics'.

  6. The ribosome quality control pathway can access nascent polypeptides stalled at the Sec61 translocon.

    PubMed

    von der Malsburg, Karina; Shao, Sichen; Hegde, Ramanujan S

    2015-06-15

    Cytosolic ribosomes that stall during translation are split into subunits, and nascent polypeptides trapped in the 60S subunit are ubiquitinated by the ribosome quality control (RQC) pathway. Whether the RQC pathway can also target stalls during cotranslational translocation into the ER is not known. Here we report that listerin and NEMF, core RQC components, are bound to translocon-engaged 60S subunits on native ER membranes. RQC recruitment to the ER in cultured cells is stimulated by translation stalling. Biochemical analyses demonstrated that translocon-targeted nascent polypeptides that subsequently stall are polyubiquitinated in 60S complexes. Ubiquitination at the translocon requires cytosolic exposure of the polypeptide at the ribosome-Sec61 junction. This exposure can result from either failed insertion into the Sec61 channel or partial backsliding of translocating nascent chains. Only Sec61-engaged nascent chains early in their biogenesis were relatively refractory to ubiquitination. Modeling based on recent 60S-RQC and 80S-Sec61 structures suggests that the E3 ligase listerin accesses nascent polypeptides via a gap in the ribosome-translocon junction near the Sec61 lateral gate. Thus the RQC pathway can target stalled translocation intermediates for degradation from the Sec61 channel.

  7. The ribosome quality control pathway can access nascent polypeptides stalled at the Sec61 translocon

    PubMed Central

    von der Malsburg, Karina; Shao, Sichen; Hegde, Ramanujan S.

    2015-01-01

    Cytosolic ribosomes that stall during translation are split into subunits, and nascent polypeptides trapped in the 60S subunit are ubiquitinated by the ribosome quality control (RQC) pathway. Whether the RQC pathway can also target stalls during cotranslational translocation into the ER is not known. Here we report that listerin and NEMF, core RQC components, are bound to translocon-engaged 60S subunits on native ER membranes. RQC recruitment to the ER in cultured cells is stimulated by translation stalling. Biochemical analyses demonstrated that translocon-targeted nascent polypeptides that subsequently stall are polyubiquitinated in 60S complexes. Ubiquitination at the translocon requires cytosolic exposure of the polypeptide at the ribosome–Sec61 junction. This exposure can result from either failed insertion into the Sec61 channel or partial backsliding of translocating nascent chains. Only Sec61-engaged nascent chains early in their biogenesis were relatively refractory to ubiquitination. Modeling based on recent 60S–RQC and 80S–Sec61 structures suggests that the E3 ligase listerin accesses nascent polypeptides via a gap in the ribosome–translocon junction near the Sec61 lateral gate. Thus the RQC pathway can target stalled translocation intermediates for degradation from the Sec61 channel. PMID:25877867

  8. Controlling the taste receptor accessible structure of rebaudioside A via binding to bovine serum albumin.

    PubMed

    Mudgal, Samriddh; Keresztes, Ivan; Feigenson, Gerald W; Rizvi, S S H

    2016-04-15

    We illustrate a method that uses bovine serum albumin (BSA) to control the receptor-accessible part of rebaudioside A (Reb A). The critical micelle concentration (CMC) of Reb A was found to be 4.5 mM and 5 mM at pH 3 and 6.7 respectively. NMR studies show that below its CMC, Reb A binds weakly to BSA to generate a Reb A-protein complex ("RPC"), which is only modestly stable under varying conditions of pH (3.0-6.7) and temperature (4-40°C) with its binding affinities determined to be in the range of 5-280 mM. Furthermore, saturation transfer difference (STD) NMR experiments confirm that the RPC has fast exchange of the bitterness-instigating diterpene of Reb A into the binding sites of BSA. Our method can be used to alter the strength of Reb A-receptor interaction, as a result of binding of Reb A to BSA, which may ultimately lead to moderation of its taste.

  9. A general framework for robust control in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Bewley, Thomas R.; Temam, Roger; Ziane, Mohammed

    2000-04-01

    The application of optimal control theory to complex problems in fluid mechanics has proven to be quite effective when complete state information from high-resolution numerical simulations is available [P. Moin, T.R. Bewley, Appl. Mech. Rev., Part 2 47 (6) (1994) S3-S13; T.R. Bewley, P. Moin, R. Temam, J. Fluid Mech. (1999), submitted for publication]. In this approach, an iterative optimization algorithm based on the repeated computation of an adjoint field is used to optimize the controls for finite-horizon nonlinear flow problems [F. Abergel, R. Temam, Theoret. Comput. Fluid Dyn. 1 (1990) 303-325]. In order to extend this infinite-dimensional optimization approach to control externally disturbed flows in which the controls must be determined based on limited noisy flow measurements alone, it is necessary that the controls computed be insensitive to both state disturbances and measurement noise. For this reason, robust control theory, a generalization of optimal control theory, has been examined as a technique by which effective control algorithms which are insensitive to a broad class of external disturbances may be developed for a wide variety of infinite-dimensional linear and nonlinear problems in fluid mechanics. An aim of the present paper is to put such algorithms into a rigorous mathematical framework, for it cannot be assumed at the outset that a solution to the infinite-dimensional robust control problem even exists. In this paper, conditions on the initial data, the parameters in the cost functional, and the regularity of the problem are established such that existence and uniqueness of the solution to the robust control problem can be proven. Both linear and nonlinear problems are treated, and the 2D and 3D nonlinear cases are treated separately in order to get the best possible estimates. Several generalizations are discussed and an appropriate numerical method is proposed.

  10. An Ounce of Prevention: Technologists Use Network-Access Control to Protect System Resources, Students

    ERIC Educational Resources Information Center

    Bolch, Matt

    2009-01-01

    Whether for an entire district, a single campus, or one classroom, allowing authorized access to a computer network can be fraught with challenges. The login process should be fairly seamless to approved users, giving them speedy access to approved Web sites, databases, and other sources of information. It also should be tough on unauthorized…

  11. Guaranteeing synchronous message deadlines with the timed token medium access control protocol

    NASA Technical Reports Server (NTRS)

    Agrawal, Gopal; Chen, Baio; Zhao, Wei; Davari, Sadegh

    1992-01-01

    We study the problem of guaranteeing synchronous message deadlines in token ring networks where the timed token medium access control protocol is employed. Synchronous capacity, defined as the maximum time for which a node can transmit its synchronous messages every time it receives the token, is a key parameter in the control of synchronous message transmission. To ensure the transmission of synchronous messages before their deadlines, synchronous capacities must be properly allocated to individual nodes. We address the issue of appropriate allocation of the synchronous capacities. Several synchronous capacity allocation schemes are analyzed in terms of their ability to satisfy deadline constraints of synchronous messages. We show that an inappropriate allocation of the synchronous capacities could cause message deadlines to be missed even if the synchronous traffic is extremely low. We propose a scheme called the normalized proportional allocation scheme which can guarantee the synchronous message deadlines for synchronous traffic of up to 33 percent of available utilization. To date, no other synchronous capacity allocation scheme has been reported to achieve such substantial performance. Another major contribution of this paper is an extension to the previous work on the bounded token rotation time. We prove that the time elapsed between any consecutive visits to a particular node is bounded by upsilon TTRT, where TTRT is the target token rotation time set up at system initialization time. The previous result by Johnson and Sevcik is a special case where upsilon = 2. We use this result in the analysis of various synchronous allocation schemes. It can also be applied in other similar studies.

  12. Flow around a semicircular cylinder with passive flow control mechanisms

    NASA Astrophysics Data System (ADS)

    Hamed, A. M.; Vega, J.; Liu, B.; Chamorro, L. P.

    2017-03-01

    Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number Re≈ 3.2× 10^4 based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of ˜25%.

  13. Adaptive mechanism-based congestion control for networked systems

    NASA Astrophysics Data System (ADS)

    Liu, Zhi; Zhang, Yun; Chen, C. L. Philip

    2013-03-01

    In order to assure the communication quality in network systems with heavy traffic and limited bandwidth, a new ATRED (adaptive thresholds random early detection) congestion control algorithm is proposed for the congestion avoidance and resource management of network systems. Different to the traditional AQM (active queue management) algorithms, the control parameters of ATRED are not configured statically, but dynamically adjusted by the adaptive mechanism. By integrating with the adaptive strategy, ATRED alleviates the tuning difficulty of RED (random early detection) and shows a better control on the queue management, and achieve a more robust performance than RED under varying network conditions. Furthermore, a dynamic transmission control protocol-AQM control system using ATRED controller is introduced for the systematic analysis. It is proved that the stability of the network system can be guaranteed when the adaptive mechanism is finely designed. Simulation studies show the proposed ATRED algorithm achieves a good performance in varying network environments, which is superior to the RED and Gentle-RED algorithm, and providing more reliable service under varying network conditions.

  14. Are Articulatory Settings Mechanically Advantageous for Speech Motor Control?

    PubMed Central

    Ramanarayanan, Vikram; Lammert, Adam; Goldstein, Louis; Narayanan, Shrikanth

    2014-01-01

    We address the hypothesis that postures adopted during grammatical pauses in speech production are more “mechanically advantageous” than absolute rest positions for facilitating efficient postural motor control of vocal tract articulators. We quantify vocal tract posture corresponding to inter-speech pauses, absolute rest intervals as well as vowel and consonant intervals using automated analysis of video captured with real-time magnetic resonance imaging during production of read and spontaneous speech by 5 healthy speakers of American English. We then use locally-weighted linear regression to estimate the articulatory forward map from low-level articulator variables to high-level task/goal variables for these postures. We quantify the overall magnitude of the first derivative of the forward map as a measure of mechanical advantage. We find that postures assumed during grammatical pauses in speech as well as speech-ready postures are significantly more mechanically advantageous than postures assumed during absolute rest. Further, these postures represent empirical extremes of mechanical advantage, between which lie the postures assumed during various vowels and consonants. Relative mechanical advantage of different postures might be an important physical constraint influencing planning and control of speech production. PMID:25133544

  15. Suppressing NOM access to controlled porous TiO2 particles enhances the decomposition of target water contaminants

    EPA Science Inventory

    Suppressing access of natural organic matter (NOM) to TiO2 is a key to the successful photocatalytic decomposition of a target contaminant in water. This study first demonstrates simply controlling the porous structure of TiO2 can significantly improve the selective oxidation.

  16. Targeting health subsidies through a non-price mechanism: A randomized controlled trial in Kenya

    PubMed Central

    Dupas, Pascaline; Hoffmann, Vivian; Kremer, Michael; Zwane, Alix Peterson

    2016-01-01

    Free provision of preventive health products can dramatically increase access in low income countries. A cost concern about free provision is that some recipients may not use the product, wasting resources (over-inclusion). Yet charging a price to screen out non-users may screen out poor people who need and would use the product (over-exclusion). We report on a randomized controlled trial of a screening mechanism that combines the free provision of chlorine solution for water treatment with a small non-monetary cost (household vouchers that need to be redeemed monthly in order). Relative to a non-voucher free distribution program, this mechanism reduces the quantity of chlorine procured by 60 percentage points, but reduces the share of households whose stored water tests positive for chlorine residual by only one percentage point, dramatically improving the tradeoff between over-inclusion and over-exclusion. PMID:27563091

  17. Potential Mechanisms of Cancer Prevention by Weight Control

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Wang, Weiqun

    Weight control via dietary caloric restriction and/or physical activity has been demonstrated in animal models for cancer prevention. However, the underlying mechanisms are not fully understood. Body weight loss due to negative energy balance significantly reduces some metabolic growth factors and endocrinal hormones such as IGF-1, leptin, and adiponectin, but enhances glucocorticoids, that may be associated with anti-cancer mechanisms. In this review, we summarized the recent studies related to weight control and growth factors. The potential molecular targets focused on those growth factors- and hormones-dependent cellular signaling pathways are further discussed. It appears that multiple factors and multiple signaling cascades, especially for Ras-MAPK-proliferation and PI3K-Akt-anti-apoptosis, could be involved in response to weight change by dietary calorie restriction and/or exercise training. Considering prevalence of obesity or overweight that becomes apparent over the world, understanding the underlying mechanisms among weight control, endocrine change and cancer risk is critically important. Future studies using "-omics" technologies will be warrant for a broader and deeper mechanistic information regarding cancer prevention by weight control.

  18. The Dark Energy Spectroscopic Instrument (DESI) instrument mechanism control systems

    NASA Astrophysics Data System (ADS)

    Coker, Carl T.; Pappalardo, Daniel; Pogge, Richard; Martini, Paul; Derwent, Mark; O'Brien, Thomas P.; Honscheid, Klaus

    2016-08-01

    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We present the design details of the instrument mechanism control systems for the spectrographs. Each spectrograph has a stand-alone mechanism control box that operates the unit's four remotely-operated mechanisms (two shutters and two Hartmannn doors), and provides a suite of temperature and humidity sensors. Each control box is highly modular, and is operated by a dedicated on-board Linux computer to provide all of the control and monitoring functions. We describe our solution for integrating a number of network-connected devices within each unit spectrograph, and describe the basic software architecture.

  19. A Brief Survey of Media Access Control, Data Link Layer, and Protocol Technologies for Lunar Surface Communications

    NASA Technical Reports Server (NTRS)

    Wallett, Thomas M.

    2009-01-01

    This paper surveys and describes some of the existing media access control and data link layer technologies for possible application in lunar surface communications and the advanced wideband Direct Sequence Code Division Multiple Access (DSCDMA) conceptual systems utilizing phased-array technology that will evolve in the next decade. Time Domain Multiple Access (TDMA) and Code Division Multiple Access (CDMA) are standard Media Access Control (MAC) techniques that can be incorporated into lunar surface communications architectures. Another novel hybrid technique that is recently being developed for use with smart antenna technology combines the advantages of CDMA with those of TDMA. The relatively new and sundry wireless LAN data link layer protocols that are continually under development offer distinct advantages for lunar surface applications over the legacy protocols which are not wireless. Also several communication transport and routing protocols can be chosen with characteristics commensurate with smart antenna systems to provide spacecraft communications for links exhibiting high capacity on the surface of the Moon. The proper choices depend on the specific communication requirements.

  20. Report: EPA Could Improve Physical Access and Service Continuity/Contingency Controls for Financial and Mixed-Financial Systems Located at its Research Triangle Park Campus

    EPA Pesticide Factsheets

    Report #2006-P-00005, December 14, 2005. Controls needed to be improved in areas such as visitor access to facilities, use of contractor access badges, and general physical access to the NCC, computer rooms outside the NCC, and media storage rooms.

  1. Dynamic Inversion based Control of a Docking Mechanism

    NASA Technical Reports Server (NTRS)

    Kulkarni, Nilesh V.; Ippolito, Corey; Krishnakumar, Kalmanje

    2006-01-01

    The problem of position and attitude control of the Stewart platform based docking mechanism is considered motivated by its future application in space missions requiring the autonomous docking capability. The control design is initiated based on the framework of the intelligent flight control architecture being developed at NASA Ames Research Center. In this paper, the baseline position and attitude control system is designed using dynamic inversion with proportional-integral augmentation. The inverse dynamics uses a Newton-Euler formulation that includes the platform dynamics, the dynamics of the individual legs along with viscous friction in the joints. Simulation results are presented using forward dynamics simulated by a commercial physics engine that builds the system as individual elements with appropriate joints and uses constrained numerical integration,

  2. [Genetic control of efficient leaf rust resistance in collection accessions of barley Hordeum vulgare L].

    PubMed

    Tyryshkin, L G

    2009-03-01

    Leaf rust resistance was studied in barley accessions from the worldwide collection of the All-Russia Institute of Plant Industry. Most accessions described as highly resistant in the literature proved susceptible. High resistance at the juvenile stage was observed only for the cultivars Henry, Cebada Capa, Forrajera Klein, and Scarlet. Hybrid analysis and phytopathological tests showed that the cultivar Scarlet had one dominant resistance gene, Rph7. Adult resistance was demonstrated for accession NB-3002 from Nepal, which proved to have one dominant gene on evidence of hybrid analysis.

  3. Analysis of femtosecond quantum control mechanisms with colored double pulses

    SciTech Connect

    Vogt, Gerhard; Nuernberger, Patrick; Selle, Reimer; Dimler, Frank; Brixner, Tobias; Gerber, Gustav

    2006-09-15

    Fitness landscapes based on a limited number of laser pulse shape parameters can elucidate reaction pathways and can help to find the underlying control mechanism of optimal pulses determined by adaptive femtosecond quantum control. In a first experiment, we employ colored double pulses and systematically scan both the temporal subpulse separation and the relative amplitude of the two subpulses to acquire fitness landscapes. Comparison with results obtained from a closed-loop experiment demonstrates the capability of fitness landscapes for the revelation of possible control mechanisms. In a second experiment, using transient absorption spectroscopy, we investigate and compare the dependence of the excitation efficiency of the solvated dye molecule 5,5{sup '}-dichloro-11-diphenylamino-3,3{sup '}-diethyl-10,12-ethylene thiatricarbocyanine perchlorate (IR140) on selected pulse shapes in two parametrizations. The results show that very different pulse profiles can be equivalently adequate to maximize a given control objective. Fitness landscapes thus provide valuable information about different pathways along which a molecular system can be controlled with shaped laser pulses.

  4. Mechanisms of abscisic acid-mediated control of stomatal aperture.

    PubMed

    Munemasa, Shintaro; Hauser, Felix; Park, Jiyoung; Waadt, Rainer; Brandt, Benjamin; Schroeder, Julian I

    2015-12-01

    Drought stress triggers an increase in the level of the plant hormone abscisic acid (ABA), which initiates a signaling cascade to close stomata and reduce water loss. Recent studies have revealed that guard cells control cytosolic ABA concentration through the concerted actions of biosynthesis, catabolism as well as transport across membranes. Substantial progress has been made at understanding the molecular mechanisms of how the ABA signaling core module controls the activity of anion channels and thereby stomatal aperture. In this review, we focus on our current mechanistic understanding of ABA signaling in guard cells including the role of the second messenger Ca(2+) as well as crosstalk with biotic stress responses.

  5. Optimal control of underactuated mechanical systems: A geometric approach

    NASA Astrophysics Data System (ADS)

    Colombo, Leonardo; Martín De Diego, David; Zuccalli, Marcela

    2010-08-01

    In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

  6. The alternating access mechanism of transport as observed in the sodium-hydantoin transporter Mhp1

    PubMed Central

    Weyand, Simone; Shimamura, Tatsuro; Beckstein, Oliver; Sansom, Mark S. P.; Iwata, So; Henderson, Peter J. F.; Cameron, Alexander D.

    2011-01-01

    Secondary active transporters move molecules across cell membranes by coupling this process to the energetically favourable downhill movement of ions or protons along an electrochemical gradient. They function by the alternating access model of transport in which, through conformational changes, the substrate binding site alternately faces either side of the membrane. Owing to the difficulties in obtaining the crystal structure of a single transporter in different conformational states, relatively little structural information is known to explain how this process occurs. Here, the structure of the sodium-benzylhydantoin transporter, Mhp1, from Microbacterium liquefaciens, has been determined in three conformational states; from this a mechanism is proposed for switching from the outward-facing open conformation through an occluded structure to the inward-facing open state. PMID:21169684

  7. Mechanical control of spin states in single molecules

    NASA Astrophysics Data System (ADS)

    Parks, J. J.; Champagne, A. R.; Costi, T. A.; Pasupathy, A. N.; Shum, W. W.; Neuscamman, E.; Chan, G. K.-L.; Abruña, H. D.; Ralph, D. C.

    2010-03-01

    We study individual Co(tpy-SH)2 complexes by connecting them within mechanically controllable break-junction devices that allow us to controllably stretch the molecule while measuring its electrical conductance. At low temperature, this molecule produces the Kondo effect, observed as a peak in the conductance at zero bias. We find that as a function of stretching the Kondo peak splits in two, in distinct contrast to behavior observed in spin-1/2 molecules. The temperature dependence of the Kondo signal for the unstretched molecule is in agreement with the scaling prediction for an underscreened S = 1 Kondo effect. The splitting of the Kondo resonance by mechanical stretching can be explained by a spin-orbit-induced lifting of the degeneracy of the S = 1 triplet upon distortion from octahedral symmetry of the Co ion. We observe evidence of the resultant spin anisotropy in the magnetic-field dependence of the Kondo peaks.

  8. Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Slominski, Eric C.

    2003-01-01

    It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

  9. Mechanical stress-controlled tunable active frequency-selective surface

    NASA Astrophysics Data System (ADS)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  10. Multi-finger prehension: control of a redundant mechanical system.

    PubMed

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  11. DOE`s nation-wide system for access control can solve problems for the federal government

    SciTech Connect

    Callahan, S.; Tomes, D.; Davis, G.; Johnson, D.; Strait, S.

    1996-07-01

    The U.S. Department of Energy`s (DOE`s) ongoing efforts to improve its physical and personnel security systems while reducing its costs, provide a model for federal government visitor processing. Through the careful use of standardized badges, computer databases, and networks of automated access control systems, the DOE is increasing the security associated with travel throughout the DOE complex, and at the same time, eliminating paperwork, special badging, and visitor delays. The DOE is also improving badge accountability, personnel identification assurance, and access authorization timeliness and accuracy. Like the federal government, the DOE has dozens of geographically dispersed locations run by many different contractors operating a wide range of security systems. The DOE has overcome these obstacles by providing data format standards, a complex-wide virtual network for security, the adoption of a standard high security system, and an open-systems-compatible link for any automated access control system. If the location`s level of security requires it, positive visitor identification is accomplished by personal identification number (PIN) and/or by biometrics. At sites with automated access control systems, this positive identification is integrated into the portals.

  12. Rate-Controlling Mechanisms in Five-Power-Law Creep

    SciTech Connect

    Michael E. Kassner

    2004-04-20

    OAK-B135 Rate-Controlling Mechanisms in Five-Power-Law Creep. The initial grant emphasized the rate-controlling processes for five power-law creep. The effort has six aspects: (1) Theory of Taylor hardening from the Frank dislocation network in five power law substructures. (2) The dual dynamical and hardening nature of dislocations in five power law substructures. (3) Determination of the existence of long-range internal stress in five-power law creep dislocation substructures. (4) Dynamic recovery mechanisms associated with dislocation heterogeneities during five power law creep. (5) Versatility of five power law creep concept to other (hcp) crystal structures. (6) Writing of a book on ''Fundamental of Creep in Metals and Alloys'' by M.E. Kassner and Maria-Teresa Perez-Frado (postdoctoral scholar, funded by this project) Elsevier Press, 2004, in press. These areas are consistent with the original goals of this project as delineated in the original proposal to Basic Energy Sciences. The progress in each of these areas will be discussed separately and there will be an attempt to tie each aspect together so as to allow a summary regarding the conclusions with respect to the rate-controlling mechanisms of five power-law creep.

  13. Controls upon microbial accessibility to soil organic matter following woody plant encroachment into grasslands

    NASA Astrophysics Data System (ADS)

    Creamer, C. A.; Boutton, T. W.; Filley, T. R.

    2009-12-01

    Woody plant encroachment (WPE) into savannas and grasslands is a global phenomenon that alters soil organic matter (SOM) dynamics through changes in litter quality and quantity, soil structure, microbial ecology, and soil hydrology. To elucidate the controls upon microbial accessibility to SOM, bulk soils from a chronosequence of progressive WPE into native grasslands at the Texas A&M Agricultural Experimental Station La Copita Research Area were incubated for one year. The quantity and stable carbon isotope composition of respired CO2, plant biopolymer chemistry in SOM, and microbial community structure were tracked. Respiration rates declined steadily over the course of the experiment with 15-25% of the total CO2 respired released in the first month of incubation. Between 8 and 18% of the total carbon was mineralized to CO2 throughout the incubation. After day 84 a significantly (p < 0.05) greater portion of carbon was mineralized from soils of older woody clusters (34-86 years) than from soils of younger clusters (14-23 years) and the native grassland. Approximately 80% of patterns seen in cumulative CO2 loss could be explained by the proportions of macro- and micro-aggregates within each soil, suggesting soil structure is a major controlling factor of respiration rates. Despite documented carbon accrual within La Copita soils due to WPE, we observed no evidence of enhanced carbon stabilization in these respiration experiments. In fact, a greater proportion of total carbon was lost from the soil of mature woody stands than from young stands, suggesting carbon accumulation observed with WPE may be due to greater input rates or microbial dynamics not captured in the laboratory incubation. A cluster approximately 34 years in age represents a transition point in WPE where respiration dynamics become distinct between grassland and wooded elements. By day 84 of the incubation CO2 respired from all soils was depleted with respect to bulk SOM (1.5 to 5‰) and this

  14. Long-Range Control of Gene Expression: Emerging Mechanisms and Disruption in Disease

    PubMed Central

    Kleinjan, Dirk A.; van Heyningen, Veronica

    2005-01-01

    Transcriptional control is a major mechanism for regulating gene expression. The complex machinery required to effect this control is still emerging from functional and evolutionary analysis of genomic architecture. In addition to the promoter, many other regulatory elements are required for spatiotemporally and quantitatively correct gene expression. Enhancer and repressor elements may reside in introns or up- and downstream of the transcription unit. For some genes with highly complex expression patterns—often those that function as key developmental control genes—the cis-regulatory domain can extend long distances outside the transcription unit. Some of the earliest hints of this came from disease-associated chromosomal breaks positioned well outside the relevant gene. With the availability of wide-ranging genome sequence comparisons, strong conservation of many noncoding regions became obvious. Functional studies have shown many of these conserved sites to be transcriptional regulatory elements that sometimes reside inside unrelated neighboring genes. Such sequence-conserved elements generally harbor sites for tissue-specific DNA-binding proteins. Developmentally variable chromatin conformation can control protein access to these sites and can regulate transcription. Disruption of these finely tuned mechanisms can cause disease. Some regulatory element mutations will be associated with phenotypes distinct from any identified for coding-region mutations. PMID:15549674

  15. Control strategies and mechanisms for active control of sound transmission into a vibro-acoustic enclosure

    NASA Astrophysics Data System (ADS)

    Jin, Guoyong; Feng, Na; Yang, Tiejun

    2011-06-01

    An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.

  16. Control of cardiac alternans by mechanical and electrical feedback

    NASA Astrophysics Data System (ADS)

    Yapari, Felicia; Deshpande, Dipen; Belhamadia, Youssef; Dubljevic, Stevan

    2014-07-01

    A persistent alternation in the cardiac action potential duration has been linked to the onset of ventricular arrhythmia, which may lead to sudden cardiac death. A coupling between these cardiac alternans and the intracellular calcium dynamics has also been identified in previous studies. In this paper, the system of PDEs describing the small amplitude of alternans and the alternation of peak intracellular Ca2+ are stabilized by optimal boundary and spatially distributed actuation. A simulation study demonstrating the successful annihilation of both alternans on a one-dimensional cable of cardiac cells by utilizing the full-state feedback controller is presented. Complimentary to these studies, a three variable Nash-Panfilov model is used to investigate alternans annihilation via mechanical (or stretch) perturbations. The coupled model includes the active stress which defines the mechanical properties of the tissue and is utilized in the feedback algorithm as an independent input from the pacing based controller realization in alternans annihilation. Simulation studies of both control methods demonstrate that the proposed methods can successfully annihilate alternans in cables that are significantly longer than 1 cm, thus overcoming the limitations of earlier control efforts.

  17. A Novel Reference Security Model with the Situation Based Access Policy for Accessing EPHR Data.

    PubMed

    Gope, Prosanta; Amin, Ruhul

    2016-11-01

    Electronic Patient Health Record (EPHR) systems may facilitate a patient not only to share his/her health records securely with healthcare professional but also to control his/her health privacy, in a convenient and easy way even in case of emergency. In order to fulfill these requirements, it is greatly desirable to have the access control mechanism which can efficiently handle every circumstance without negotiating security. However, the existing access control mechanisms used in healthcare to regulate and restrict the disclosure of patient data are often bypassed in case of emergencies. In this article, we propose a way to securely share EPHR data under any situation including break-the-glass (BtG) without compromising its security. In this regard, we design a reference security model, which consists of a multi-level data flow hierarchy, and an efficient access control framework based on the conventional Role-Based Access Control (RBAC) and Mandatory Access Control (MAC) policies.

  18. Controller modeling and evaluation for PCV electro-mechanical actuator

    NASA Technical Reports Server (NTRS)

    Parker, Joey K.

    1993-01-01

    Hydraulic actuators are currently used to operate the propellant control valves (PCV) for the space shuttle main engine (SSME) and other rocket engines. These actuators are characterized by large power to weight ratios, large force capabilities, and rapid accelerations, which favor their use in control valve applications. However, hydraulic systems are also characterized by susceptibility to contamination, which leads to frequent maintenance requirements. The Control Mechanisms Branch (EP34) of the Component Development Division of the Propulsion Laboratory at the Marshall Space Flight Center (MSFC) has been investigating the application of electromechanical actuators as replacements for the hydraulic units in PCV's over the last few years. This report deals with some testing and analysis of a PCV electromechanical actuator (EMA) designed and fabricated by HR Textron, Inc. This prototype actuator has undergone extensive testing by EP34 personnel since early 1993. At this time, the performance of the HR Textron PCV EMA does not meet requirements for position tracking.

  19. Moving Constraints as Stabilizing Controls in Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Bressan, Alberto; Rampazzo, Franco

    2010-04-01

    The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motion contain terms which are linear or quadratic with respect to time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point by means of oscillating controls. This problem is first reduced to theweak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples.

  20. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs.

    PubMed

    Morales, Julia; Yudes, Carolina; Gómez-Ariza, Carlos J; Bajo, M Teresa

    2015-01-01

    Recent behavioral findings with the AX-Continous Performance Task (AX-CPT; Morales et al., 2013) show that bilinguals only outperform monolinguals under conditions that require the highest adjustment between monitoring (proactive) and inhibitory (reactive) control, which supports the idea that bilingualism modulates the coordination of different control mechanisms. In an ERP experiment we aimed to further investigate the role that bilingualism plays in the dynamic combination of proactive and reactive control in the AX-CPT. Our results strongly indicate that bilingualism facilitates an effective adjustment between both components of cognitive control. First, we replicated previous behavioral results. Second, ERP components indicated that bilingualism influences the conflict monitoring, response inhibition and error monitoring components of control (as indexed by the N2 and P3a elicited by the probe and the error-related negativity following incorrect responses, respectively). Thus, bilinguals exerted higher reactive control than monolinguals but only when they needed to overcome the competing cue-information. These findings join others in suggesting that a better understanding of the cognitive benefits of bilingualism may require consideration of a multi-component perspective.

  1. Analysis and Simulation of Traffic Control for Resource Management in DVB-Based Broadband Satellite Access Networks

    NASA Astrophysics Data System (ADS)

    Impemba, Ernesto; Inzerilli, Tiziano

    2003-07-01

    Integration of satellite access networks with the Internet is seen as a strategic goal to achieve in order to provide ubiquitous broadband access to Internet services in Next Generation Networks (NGNs). One of the main interworking aspects which has been most studied is an efficient management of satellite resources, i.e. bandwidth and buffer space, in order to satisfy most demanding application requirements as to delay control and bandwidth assurance. In this context, resource management in DVB-S/DVB-RCS satellite technologies, emerging technologies for broadband satellite access and transport of IP applications, is a research issue largely investigated as a means to provide efficient bi-directional communications across satellites. This is in particular one of the principal goals of the SATIP6 project, sponsored within the 5th EU Research Programme Framework, i.e. IST. In this paper we present a possible approach to efficiently exploit bandwidth, the most critical resource in a broadband satellite access network, while pursuing satisfaction of delay and bandwidth requirements for applications with guaranteed QoS through a traffic control architecture to be implemented in ground terminals. Performance of this approach is assessed in terms of efficient exploitation of the uplink bandwidth and differentiation and minimization of queuing delays for most demanding applications over a time-varying capacity. Opnet simulations is used as analysis tool.

  2. Capabilities and Limitations of Tissue Size Control through Passive Mechanical Forces

    PubMed Central

    Kursawe, Jochen; Brodskiy, Pavel A.; Zartman, Jeremiah J.; Baker, Ruth E.; Fletcher, Alexander G.

    2015-01-01

    Embryogenesis is an extraordinarily robust process, exhibiting the ability to control tissue size and repair patterning defects in the face of environmental and genetic perturbations. The size and shape of a developing tissue is a function of the number and size of its constituent cells as well as their geometric packing. How these cellular properties are coordinated at the tissue level to ensure developmental robustness remains a mystery; understanding this process requires studying multiple concurrent processes that make up morphogenesis, including the spatial patterning of cell fates and apoptosis, as well as cell intercalations. In this work, we develop a computational model that aims to understand aspects of the robust pattern repair mechanisms of the Drosophila embryonic epidermal tissues. Size control in this system has previously been shown to rely on the regulation of apoptosis rather than proliferation; however, to date little work has been done to understand the role of cellular mechanics in this process. We employ a vertex model of an embryonic segment to test hypotheses about the emergence of this size control. Comparing the model to previously published data across wild type and genetic perturbations, we show that passive mechanical forces suffice to explain the observed size control in the posterior (P) compartment of a segment. However, observed asymmetries in cell death frequencies across the segment are demonstrated to require patterning of cellular properties in the model. Finally, we show that distinct forms of mechanical regulation in the model may be distinguished by differences in cell shapes in the P compartment, as quantified through experimentally accessible summary statistics, as well as by the tissue recoil after laser ablation experiments. PMID:26713738

  3. State preemption of local tobacco control policies restricting smoking, advertising, and youth access--United States, 2000-2010.

    PubMed

    2011-08-26

    Preemptive state tobacco control legislation prohibits localities from enacting tobacco control laws that are more stringent than state law. State preemption provisions can preclude any type of local tobacco control policy. The three broad types of state preemption tracked by CDC include preemption of local policies that restrict 1) smoking in workplaces and public places, 2) tobacco advertising, and 3) youth access to tobacco products. A Healthy People 2020 objective (TU-16) calls for eliminating state laws that preempt any type of local tobacco control law. A previous study reported that the number of states that preempt local smoking restrictions in one or more of three settings (government worksites, private-sector worksites, and restaurants) has decreased substantially in recent years. To measure progress toward achieving Healthy People 2020 objectives, this study expands on the previous analysis to track changes in state laws that preempt local advertising and youth access restrictions and to examine policy changes from December 31, 2000, to December 31, 2010. This new analysis found that, in contrast with the substantial progress achieved during the past decade in reducing the number of states that preempt local smoking restrictions, no progress has been made in reducing the number of states that preempt local advertising restrictions and youth access restrictions. Increased progress in removing state preemption provisions will be needed to achieve the relevant Healthy People 2020 objective.

  4. Controlling Mechanical Properties of Bis-leucine Oxalyl Amide Gels

    NASA Astrophysics Data System (ADS)

    Chang, William; Carvajal, Daniel; Shull, Kenneth

    2011-03-01

    is-leucine oxalyl amide is a low molecular weight gelator capable of gelling polar and organic solvents. A fundamental understanding of self-assembled systems can lead to new methods in drug delivery and the design of new soft material systems. An important feature of self-assembled systems are the intermolecular forces between solvent and gelator molecule; by changing the environment the gel is in, the mechanical properties also change. In this project two variables were considered: the degree of neutralization present for the gelator molecule from neutral to completely ionized, and the concentration of the gelator molecule, from 1 weight percent to 8 weight percent in 1-butanol. Mechanical properties were studied using displacement controlled indentation techniques and temperature sweep rheometry. It has been found that properties such as the storage modulus, gelation temperature and maximum stress allowed increase with bis-leucine oxalyl amide concentration. The results from this study establish a 3-d contour map between the gelator concentration, the gelator degree of ionization and mechanical properties such as storage modulus and maximum stress allowed. The intermolecular forces between the bis-leucine low molecular weight gelator and 1-butanol govern the mechanical properties of the gel system, and understanding these interactions will be key to rationally designed self-assembled systems.

  5. Mechanical control of mitotic progression in single animal cells.

    PubMed

    Cattin, Cedric J; Düggelin, Marcel; Martinez-Martin, David; Gerber, Christoph; Müller, Daniel J; Stewart, Martin P

    2015-09-08

    Despite the importance of mitotic cell rounding in tissue development and cell proliferation, there remains a paucity of approaches to investigate the mechanical robustness of cell rounding. Here we introduce ion beam-sculpted microcantilevers that enable precise force-feedback-controlled confinement of single cells while characterizing their progression through mitosis. We identify three force regimes according to the cell response: small forces (∼5 nN) that accelerate mitotic progression, intermediate forces where cells resist confinement (50-100 nN), and yield forces (>100 nN) where a significant decline in cell height impinges on microtubule spindle function, thereby inhibiting mitotic progression. Yield forces are coincident with a nonlinear drop in cell height potentiated by persistent blebbing and loss of cortical F-actin homogeneity. Our results suggest that a buildup of actomyosin-dependent cortical tension and intracellular pressure precedes mechanical failure, or herniation, of the cell cortex at the yield force. Thus, we reveal how the mechanical properties of mitotic cells and their response to external forces are linked to mitotic progression under conditions of mechanical confinement.

  6. An efficient key-management scheme for hierarchical access control in e-medicine system.

    PubMed

    Wu, Shuhua; Chen, Kefei

    2012-08-01

    In e-medicine system, the sharing of patients' medical histories scattered among medical institutions through the Internet is highly desirable. The most immediate cryptographic need certainly is an efficient key management method to solve dynamic access problems in a user hierarchy. In this paper, we propose a practical solution for dynamic access problem in a user hierarchy based on hybrid cryptosystems. When compared with Nikooghadam et al.'s scheme proposed most recently, the time complexity and the required storage space is reduced significantly. Moreover, it provides provable security, and is easy to implement. Therefore, our scheme is more suitable for e-medicine system.

  7. Mechanics of precisely controlled thin film buckling on Elastomeric substrate.

    SciTech Connect

    Sun, Y.; Jiang, H.; Rogers, J.; Huang, Y.; Arizone State Univ.; Beckman Inst.; University of Illinois Urbana-Champaign

    2007-01-01

    Stretchable electronics has many important and emerging applications. Sun et al. [Nature Nanotech. 1, 201 (2006)] recently demonstrated stretchable electronics based on precisely controlled buckle geometries in GaAs and Si nanoribbons on elastomeric substrates. A nonlinear buckling model is presented in this letter to study the mechanics of this type of thin film/substrate system. An analytical solution is obtained for the buckling geometry (wavelength and amplitude) and the maximum strain in buckled thin film. This solution agrees very well with the experiments, and shows explicitly how buckling can significantly reduce the thin film strain to achieve the system stretchability.

  8. DoD Needs to Improve Screening and Access Controls for General Public Tenants Leasing Housing on Military Installations (REDACTED)

    DTIC Science & Technology

    2016-04-01

    have the actual signature of the authorizing official for your organization. We cannot accept the /Signed/ symbol in place of the actual signature...Introduction DODIG-2016-072 │ 1 Introduction Objective Our audit objective was to determine whether DoD had adequate security controls in place for the... working with installations without a direct connection to NCIC via a state terminal to provide access through OpenFox. In addition, procedures for

  9. Fluorination Enables a Ligand-Controlled Regiodivergent Palladium-Catalyzed Decarboxylative Allylation Reaction to Access α,α-Difluoroketones

    PubMed Central

    Yang, Ming–Hsiu; Orsi, Douglas L.

    2015-01-01

    α,α-Difluoroketones possess unique physicochemical properties that are useful for developing therapeutics and probes for chemical biology. In order to access the α-allyl-α,α-difluoroketone substructure, complementary Pd-catalyzed decarboxylative allylation reactions were developed to provide linear and branched α-allyl-α,α-difluoroketones. For these orthogonal processes, the regioselectivity was uniquely controlled by fluorination of the substrate and the structure of ligand. PMID:25581845

  10. An effective and secure key-management scheme for hierarchical access control in E-medicine system.

    PubMed

    Odelu, Vanga; Das, Ashok Kumar; Goswami, Adrijit

    2013-04-01

    Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

  11. Frontal theta as a mechanism for cognitive control

    PubMed Central

    Cavanagh, James F.; Frank, Michael J.

    2014-01-01

    Recent advancements in cognitive neuroscience have afforded a description of neural responses in terms of latent algorithmic operations. However, the adoption of this approach to human scalp EEG has been more limited, despite the ability of this methodology to quantify canonical neuronal processes. Here we provide evidence that theta band activities over the mid-frontal cortex appear to reflect a common computation used for realizing the need for cognitive control. Moreover, by virtue of inherent properties of field oscillations, these theta band processes may be used to communicate this need and subsequently implement such control across disparate brain regions. Frontal theta is thus a compelling candidate mechanism by which emergent processes such as ‘cognitive control’ may be biophysically realized. PMID:24835663

  12. RNA-based control mechanisms of Clostridium difficile.

    PubMed

    Soutourina, Olga

    2017-02-16

    Clostridium difficile (CD)-associated diarrhoea is currently the most prevalent nosocomial diarrhoea worldwide. Many characteristics of CD pathogenicity remain poorly understood. Recent data strongly indicate the importance of an RNA network for the control of gene expression in CD. More than 200 regulatory RNAs have been identified by deep sequencing and targeted approaches, including Hfq-dependent trans riboregulators, cis-antisense RNAs, CRISPR RNAs, and c-di-GMP-responsive riboswitches. These regulatory RNAs are involved in the control of major processes in the CD infection cycle, for example motility, biofilm formation, adhesion, sporulation, stress response, and defence against bacteriophages. We will discuss recent advances in elucidation of the original features of RNA-based mechanisms in this important enteropathogen. This knowledge may pave the way for further discoveries in this emergent field.

  13. On Mechanism of Plasma-shock-based Flow Control

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Li, Y. H.; Liang, H.; Jia, M.; Song, H. M.

    2011-09-01

    The mechanism of plasma-shock-based flow control was studied. Due to the high reduced electric field strength and peak power in the nanosecond discharge, a large quantity of high-energy electrons are produced. The quenching of the electronically excited states of N2, the dissociation of O2 and N2, and the recombination of molecular ions with electrons cause fast heating of local air near the electrode edge and fast air pressure rise, thus inducing shock waves. The effectiveness of using nanosecond discharge plasma aerodynamic actuation to improve flow separation control capability was validated at the freestream velocity of 150 m/s. Critical stall angle, lift and drag of NACA 0015 airfoil were measured with and without the nanosecond discharge plasma aerodynamic actuation in the wind tunnel experiments.

  14. Multi-component access to a commercially available weight loss program: A randomized controlled trial

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined weight loss between a community-based, intensive behavioral counseling program (Weight Watchers PointsPlus that included three treatment access modes and a self-help condition. A total of 292 participants were randomized to a Weight Watchers (WW; n=147) or a self-help condition (...

  15. 30 CFR 816.66 - Use of explosives: Blasting signs, warnings, and access control.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... audible blast warning and all-clear signals that are in use, and which explain the marking of blasting... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Use of explosives: Blasting signs, warnings... STANDARDS-SURFACE MINING ACTIVITIES § 816.66 Use of explosives: Blasting signs, warnings, and access...

  16. 50 CFR 648.82 - Effort-control program for NE multispecies limited access vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...(a)(2), a vessel issued a limited access NE multispecies permit may not fish for, possess, or land.... (ii) A vessel may not fish for, possess, or land regulated species from March 1 through March 20 of... DAS may be used in the NE multispecies fishery to harvest and land stocks of regulated species...

  17. 50 CFR 648.82 - Effort-control program for NE multispecies limited access vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...(a)(2), a vessel issued a limited access NE multispecies permit may not fish for, possess, or land.... (ii) A vessel may not fish for, possess, or land regulated species from March 1 through March 20 of... DAS may be used in the NE multispecies fishery to harvest and land stocks of regulated species...

  18. Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

    NASA Technical Reports Server (NTRS)

    Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

    1994-01-01

    There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

  19. Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

    NASA Astrophysics Data System (ADS)

    Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

    1994-02-01

    There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

  20. Mechanisms of spatial attention control in frontal and parietal cortex

    PubMed Central

    Szczepanski, Sara M.; Konen, Christina S.; Kastner, Sabine

    2010-01-01

    Theories of spatial attentional control have been largely based upon studies of patients suffering from visuo-spatial neglect, resulting from circumscribed lesions of frontal and posterior parietal cortex. In the intact brain, the control of spatial attention has been related to a distributed fronto-parietal attention network. Little is known about the nature of the control mechanisms exerted by this network. Here, we used a novel region-of-interest approach to relate activations of the attention network to recently described topographic areas in frontal (FEF, PreCC/IFS) and parietal cortex (IPS1-IPS5, SPL1) and to examine their spatial attention signals. We found that attention signals in most topographic areas were spatially-specific, with stronger responses when attention was directed to the contralateral than to the ipsilateral visual field. Importantly, two hemispheric asymmetries were found. First, a region in only right, but not left superior parietal lobule (SPL1) carried spatial attention signals. Second, left FEF and left posterior parietal cortex (IPS1/2) generated stronger contralateral biasing signals than their counterparts in the right hemisphere. These findings are the first to characterize spatial attention signals in topographic frontal and parietal cortex and provide a neural basis in support of an interhemispheric competition account of spatial attentional control. PMID:20053897

  1. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    SciTech Connect

    Schmidsfeld, A. von Reichling, M.

    2015-09-21

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  2. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    NASA Astrophysics Data System (ADS)

    von Schmidsfeld, A.; Reichling, M.

    2015-09-01

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  3. Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.

    PubMed

    Du, Qinghe; Zhao, Weidong; Li, Weimin; Zhang, Xuelin; Sun, Bo; Song, Houbing; Ren, Pinyi; Sun, Li; Wang, Yichen

    2016-07-01

    The prosperity of e-health is boosted by fast development of medical devices with wireless communications capability such as wearable devices, tiny sensors, monitoring equipments, etc., which are randomly distributed in clinic environments. The drastically-increasing population of such devices imposes new challenges on the limited wireless resources. To relieve this problem, key knowledge needs to be extracted from massive connection attempts dispersed in the air towards efficient access control. In this paper, a hybrid periodic-random massive access (HPRMA) scheme for wireless clinical networks employing ultra-narrow band (UNB) techniques is proposed. In particular, the proposed scheme towards accommodating a large population of devices include the following new features. On one hand, it can dynamically adjust the resource allocated for coexisting periodic and random services based on the traffic load learned from signal collision status. On the other hand, the resource allocation within periodic services is thoroughly designed to simultaneously align with the timing requests of differentiated services. Abundant simulation results are also presented to demonstrate the superiority of the proposed HPRMA scheme over baseline schemes including time-division multiple access (TDMA) and random access approach, in terms of channel utilization efficiency, packet drop ratio, etc., for the support of massive devices' services.

  4. Neural mechanisms of attentional control in mindfulness meditation.

    PubMed

    Malinowski, Peter

    2013-01-01

    The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

  5. Basic mechanisms controlling the sweeping efficiency of propagating current sheets

    NASA Astrophysics Data System (ADS)

    Berkery, J. W.; Choueiri, E. Y.

    2006-02-01

    The basic mechanisms controlling the sweeping efficiency of propagating current sheets are investigated through experiments and analytical modelling. The sweeping efficiency of a current sheet in a parallel plate gas-fed pulsed plasma accelerator is defined as the ratio of the current sheet mass to the total available propellant mass. Permeability of neutrals through the sheet, and leakage of mass out of the sheet and into a cathode wake, decrease the sweeping efficiency. The sweeping efficiency of current sheets in argon, neon, helium and hydrogen propellants at different initial pressures was determined through measurements of sheet velocity with high speed photography and of sheet mass with laser interferometry. The mechanism that controls the sweeping efficiency of propagating current sheets was found to be an interplay of two processes: the flux of mass entering the sheet and the leakage of mass at the cathode, with the former dependent on the degree of permeability and the latter dependent on the level of ion current as determined by the ion Hall parameter.

  6. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, L.R.; Crawford, D.C.

    1983-10-06

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  7. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, Lawrence R.; Crawford, Donald C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  8. Molecular mechanisms controlling the migration of striatal interneurons.

    PubMed

    Villar-Cerviño, Verona; Kappeler, Caroline; Nóbrega-Pereira, Sandrina; Henkemeyer, Mark; Rago, Luciano; Nieto, M Angela; Marín, Oscar

    2015-06-10

    In the developing telencephalon, the medial ganglionic eminence (MGE) generates many cortical and virtually all striatal interneurons. While the molecular mechanisms controlling the migration of interneurons to the cortex have been extensively studied, very little is known about the nature of the signals that guide interneurons to the striatum. Here we report that the allocation of MGE-derived interneurons in the developing striatum of the mouse relies on a combination of chemoattractive and chemorepulsive activities. Specifically, interneurons migrate toward the striatum in response to Nrg1/ErbB4 chemoattraction, and avoid migrating into the adjacent cortical territories by a repulsive activity mediated by EphB/ephrinB signaling. Our results also suggest that the responsiveness of MGE-derived striatal interneurons to these cues is at least in part controlled by the postmitotic activity of the transcription factor Nkx2-1. This study therefore reveals parallel mechanisms for the migration of MGE-derived interneurons to the striatum and the cerebral cortex.

  9. Auction Mechanism to Allocate Air Traffic Control Slots

    NASA Technical Reports Server (NTRS)

    Raffarin, Marianne

    2003-01-01

    This article deals with an auction mechanism for airspace slots, as a means of solving the European airspace congestion problem. A disequilibrium, between Air Traffic Control (ATC) services supply and ATC services demand are at the origin of almost one fourth of delays in the air transport industry in Europe. In order to tackle this congestion problem, we suggest modifying both pricing and allocation of ATC services, by setting up an auction mechanism. Objects of the auction will be the right for airlines to cross a part of the airspace, and then to benefit from ATC services over a period corresponding to the necessary time for the crossing. Allocation and payment rules have to be defined according to the objectives of this auction. The auctioneer is the public authority in charge of ATC services, whose aim is to obtain an efficient allocation. Therefore, the social value will be maximized. Another objective is to internalize congestion costs. To that end, we apply the principle of Clarke-Groves mechanism auction: each winner has to pay the externalities imposed on other bidders. The complex context of ATC leads to a specific design for this auction.

  10. Eye mechanics and their implications for eye movement control

    NASA Astrophysics Data System (ADS)

    Koene, Ansgar Roald

    2002-11-01

    The topic of this thesis is the investigation of the mechanical properties of the oculomotor system and the implications of these properties for eye movement control. The investigation was conducted by means of computer models and simulations. This allowed us to combine data from anatomy, physiology and psychophysics with basic principles of physics (mechanics) and mathematics (geometry). In chapter 2 we investigate the degree to which mechanical and neural non-linearities contribute to the kinematic differences between centrifugal and centripetal saccades. On the basis of the velocity profiles of centrifugal and centripetal saccades we calculate the forces and muscle innervations during these eye movements. This was done using an inverted model of the eye plant. Our results indicate that the non-linear force-velocity relationship (i.e. muscle viscosity) of the muscles is probably the cause of the kinematic differences between centrifugal and centripetal saccades. In chapter 3 we calculate the adjustment of the saccadic command that is necessary to compensate for the eye plant non-linearities. These calculations show that the agonist and antagonist muscles require different net saccade signal gain changes. In order to better understand how this gain change is accomplished we use the inverted model of the eye plant (chapter 2) to calculate the muscle innervation profiles of saccades with different starting orientations. Based on these calculations we conclude that the saccade signal gain changes are accomplished primarily by changes in the magnitude of the saccade signal. In chapter 4 we examine the requirements that the oculomotor system must meet for the eye to be able to make desired gaze changes and fixate at various eye orientations. We first determine how the axes of action (i.e. unit moment vectors) of the muscles are related to eye orientation and the location of the effective muscle origin (i.e. the muscle pulleys). Next we show how this relation constrains

  11. The role of the local chemical environment of Ag on the resistive switching mechanism of conductive bridging random access memories.

    PubMed

    Souchier, E; D'Acapito, F; Noé, P; Blaise, P; Bernard, M; Jousseaume, V

    2015-10-07

    Conductive bridging random access memories (CBRAMs) are one of the most promising emerging technologies for the next generation of non-volatile memory. However, the lack of understanding of the switching mechanism at the nanoscale level prevents successful transfer to industry. In this paper, Ag/GeSx/W CBRAM devices are analyzed using depth selective X-ray Absorption Spectroscopy before and after switching. The study of the local environment around Ag atoms in such devices reveals that Ag is in two very distinct environments with short Ag-S bonds due to Ag dissolved in the GeSx matrix, and longer Ag-Ag bonds related to an Ag metallic phase. These experiments allow the conclusion that the switching process involves the formation of metallic Ag nano-filaments initiated at the Ag electrode. All these experimental features are well supported by ab initio molecular dynamics simulations showing that Ag favorably bonds to S atoms, and permit the proposal of a model at the microscopic level that can explain the instability of the conductive state in these Ag-GeSx CBRAM devices. Finally, the principle of the nondestructive method described here can be extended to other types of resistive memory concepts.

  12. Phloem transport: a review of mechanisms and controls.

    PubMed

    De Schepper, Veerle; De Swaef, Tom; Bauweraerts, Ingvar; Steppe, Kathy

    2013-11-01

    It is generally believed that an osmotically generated pressure gradient drives the phloem mass flow. So far, this widely accepted Münch theory has required remarkably few adaptations, but the debate on alternative and additional hypotheses is still ongoing. Recently, a possible shortcoming of the Münch theory has been pointed out, suggesting that the Münch pressure flow is more suitable for herbs than for trees. Estimation of the phloem resistance indicates that a point might be reached in long sieve tubes where the pressure required to drive the Münch flow cannot be generated. Therefore, the relay hypothesis regained belief as it implies that the sieve tubes are shorter then the plant's axial axis. In the source phloem, three different loading strategies exist which probably result from evolutionary advantages. Passive diffusion seems to be the most primitive one, whereas active loading strategies substantially increase the growth potential. Along the transport phloem, a leakage-retrieval mechanism is observed. Appreciable amounts of carbohydrates are lost from the sieve tubes to feed the lateral sinks, while a part of these lost carbohydrates is subsequently reloaded into the sieve tubes. This mechanism is probably involved to buffer short-term irregularities in phloem turgor and gradient. In the long term, the mechanism controls the replenishment and remobilization of lateral stem storage tissues. As phloem of higher plants has multiple functions in plant development, reproduction, signalling, and growth, the fundamental understanding of the mechanisms behind phloem transport should be elucidated to increase our ability to influence plant growth and development.

  13. Fixed and flexible formularies as cost-control mechanisms.

    PubMed

    Dewa, Carolyn S; Hoch, Jeffrey S

    2003-06-01

    The purpose of this review is to consider the prevalent types of fixed and flexible formularies, the general economic principles on which they are based and the evidence for their effectiveness in controlling rising drug expenditures. The principal-agent relationship and economic model underlying the various types of formularies are described. The principal-agent model describes a relationship where there is an asymmetry of information between two parties involved in a particular task. As a result of this asymmetry of information, the party with less information (the principal) allows the party with more information (the agent) to make decisions about that task or activity for them. In the case of formularies and cost-control, the principal is the payer. Depending on the incentives offered by the formulary, the agent can alternately be the prescriber, dispenser or patient. The success of a formulary type to control costs is dependent on two main factors. First, the payer (the principal) must identify the agent for whom it is reasonable to create incentives that incorporate the financial risks associated with use of the drugs. Second, the payer must develop a structure that best aligns the principal and agent objectives. The principal-agent framework serves as the vehicle through which the authors examine five major types of formularies (i.e., closed, best available price, reference-based pricing, tiered and open formularies) and their inherent incentives and limitations. The evidence for their effectiveness as cost-control mechanisms is reviewed and the system factors that can affect formulary success will be discussed. Finally, the authors' observations are summarized and interpreted, and suggested implications for future use of formularies in controlling the costs of pharmaceutical use are offered.

  14. Neural mechanisms of brain-computer interface control.

    PubMed

    Halder, S; Agorastos, D; Veit, R; Hammer, E M; Lee, S; Varkuti, B; Bogdan, M; Rosenstiel, W; Birbaumer, N; Kübler, A

    2011-04-15

    Brain-computer interfaces (BCIs) enable people with paralysis to communicate with their environment. Motor imagery can be used to generate distinct patterns of cortical activation in the electroencephalogram (EEG) and thus control a BCI. To elucidate the cortical correlates of BCI control, users of a sensory motor rhythm (SMR)-BCI were classified according to their BCI control performance. In a second session these participants performed a motor imagery, motor observation and motor execution task in a functional magnetic resonance imaging (fMRI) scanner. Group difference analysis between high and low aptitude BCI users revealed significantly higher activation of the supplementary motor areas (SMA) for the motor imagery and the motor observation tasks in high aptitude users. Low aptitude users showed no activation when observing movement. The number of activated voxels during motor observation was significantly correlated with accuracy in the EEG-BCI task (r=0.53). Furthermore, the number of activated voxels in the right middle frontal gyrus, an area responsible for processing of movement observation, correlated (r=0.72) with BCI-performance. This strong correlation highlights the importance of these areas for task monitoring and working memory as task goals have to be activated throughout the BCI session. The ability to regulate behavior and the brain through learning mechanisms involving imagery such as required to control a BCI constitutes the consequence of ideo-motor co-activation of motor brain systems during observation of movements. The results demonstrate that acquisition of a sensorimotor program reflected in SMR-BCI-control is tightly related to the recall of such sensorimotor programs during observation of movements and unrelated to the actual execution of these movement sequences.

  15. Aging interferes central control mechanism for eccentric muscle contraction.

    PubMed

    Yao, Wan X; Li, Jinqi; Jiang, Zhiguo; Gao, Jia-Hong; Franklin, Crystal G; Huang, Yufei; Lancaster, Jack L; Yue, Guang H

    2014-01-01

    Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional magnetic resonance imaging (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.

  16. Flow control mechanism of capillary driven flow in microchannel using non-mechanical forces

    NASA Astrophysics Data System (ADS)

    Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

    2016-11-01

    The capillary driven flow in microchannel is a self-driven flow by the natural phenomenon called surface tension of the fluid. The gradients in surface tension force which influence the flow field in microchannel is generated by the modulation of contact angle through a defined hydrophilization of the PDMS (Polydimethylsiloxane) microchannel surface. PDMS which is hydrophobic in nature is treated with various surface treatments in order to convert it to hydrophilic. The contact angle made by the fluid with the PDMS microchannel surface is altered when the surface is converted from hydrophobic to hydrophilic. The flow rate of fluid in the microchannel is directly proportional to the hydrophilicity of that microchannel since the capillary force which is the driving force of the flow is dependent on the contact angle. Flow control mechanism of capillary driven flow in microchannel using non-mechanical forces is developed by treating the microchannel surfaces with various surface treatments. The precise control of the surface characteristics like hydrophilicity and roughness of the miocrochannel helps to control the capillary flow in microchannel. The flow rate variation with respect to the various surface treated channels are studied. Principal Investigator.

  17. Oversight Review: Quality Control Review of Naval Audit Service’s Special Access Program Audits

    DTIC Science & Technology

    2005-09-02

    undergo an external peer review at least once every 3 years by reviewers independent of the audit organization being reviewed. As the organization that...has audit policy and oversight responsibilities for audits in the Department of Defense, we conducted this external peer review of the NAVAUDSVC audits...requiring special access in conjunction with the Army Audit Agency’s external peer review of NAVAUDSVC non-SAP audits.

  18. Composable Distributed Access Control and Integrity Policies for Query-Based Wireless Sensor Networks

    DTIC Science & Technology

    2008-03-01

    multiple WSN policies. The construction, hybridization, and composition of well–known models is demonstrated to preserve security, sustaining...confidentiality in Bell–LaPadula’s model , integrity in Biba’s strict integrity model , and conflict of interest avoidance in the Chinese Wall. Using WASL, a multi...as defined by the security model . It is also be more flexible in that a policy file update is all that is required to modify the accesses permitted

  19. Scalable Authorization in Role-Based Access Control Using Negative Permissions and Remote Authorization

    DTIC Science & Technology

    2003-01-01

    and Hongjie Xin for making this a rewarding team experience. Thanks to Mr. Michael Warres from Sun Microsystems for being prompt and meticulous in our...Windows NT), and security policies based on the Chinese wall model for separation of duties [8]. RBAC simplifies the administration of access...connection check is sort of a first wall of defense against illegitimate users, while the JavaSpace action is more specific to a particular object, known as

  20. Sway patterns in orthostatic tremor: impairment of postural control mechanisms.

    PubMed

    Bacsi, Ann M; Fung, Victor S C; Colebatch, James G

    2005-11-01

    Sway parameters in orthostatic tremor (OT) patients were compared with age-matched controls. The effects of vision (eyes open or closed), stance width (feet apart or together), and external support (with or without) on sway and 14-18 Hz energy were measured. Sway in OT patients decreased in the presence of each of the stabilizing factors but the extent of benefit obtained by OT patients was significantly less than controls for support for the sagittal plane (22% vs. 42% decrease; P < 0.01) and feet apart in the mediolateral plane (38% vs. 65% decrease; P < 0.01). Three patients with proprioceptive loss also had a reduced response to these factors. Energy in the 14-18 Hz range did not always change in parallel with sway levels. Vision suppresses activity at the OT frequency in patients. Postural control mechanisms in OT remain responsive to postural conditions, but patients differ significantly from normals in the degree of their responsiveness. OT appears to have disruption of the normal generation or processing of proprioceptive signals as one of its important components.

  1. Analysis of the Reconfigurable Control Capabilities of a Space Access Vehicle (Preprint)

    DTIC Science & Technology

    2006-12-01

    based on dynamic inversion with a non-linear control allocator, is used to linearize the vehicle dynamics over its flight envelope and assign control ...backstepping method. Assessment of the vehicle’s ability to recover from control failures is conducted in this work for a nominal re-entry flight . 15...on dynamic inversion with a non-linear control allocator, is used to linearize the vehicle dynamics over its flight envelope and assign control tasks

  2. Chemo-mechanical control of neural stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  3. Access to Spatial Data: The Political Power of Legal Control Mechanisms

    ERIC Educational Resources Information Center

    Day, Patrice

    2012-01-01

    According to the U.S. Supreme Court ("Island Trees School District v. Pico," 457 U.S. 853, 1982), the Constitution presupposes that the free flow of information between the government and the public is essential to maintaining an informed citizenry, which in turn is essential to holding governments accountable. However, local governments…

  4. Control of depth of anesthesia using MUSMAR--exploring electromyography and the analgesic dose as accessible disturbances.

    PubMed

    Nunes, Catarina S; Mendonça, Teresa; Lemos, João M; Amorim, Pedro

    2007-01-01

    The problem of controlling the level of depth of anesthesia measured by the Bispectral Index (BIS) of the electroencephalogram of patients under general anesthesia, is considered. It is assumed that the manipulated variable is the infusion rate of the hypnotic drug propofol, while the drug remifentanil is also administered for analgesia. Since these two drugs interact, the administration rate of remifentanil is considered as an accessible disturbance in combination with the level of electromyography (EMG) that also interferes with the BIS signal. In order to tackle the high uncertainty present on the system, the predictive adaptive controller MUSMAR is used. The performance of the controller is illustrated by means of simulation with 45 patient individual adjusted models, which incorporate the effect of the drugs interaction on BIS. This controller structure proved to be robust to the EMG and remifentanil disturbances, patient variability, changing reference values and noise.

  5. International Space Station Mechanisms and Maintenance Flight Control Documentation and Training Development

    NASA Technical Reports Server (NTRS)

    Daugherty, Colin C.

    2010-01-01

    International Space Station (ISS) crew and flight controller training documentation is used to aid in training operations. The Generic Simulations References SharePoint (Gen Sim) site is a database used as an aid during flight simulations. The Gen Sim site is used to make individual mission segment timelines, data, and flight information easily accessible to instructors. The Waste and Hygiene Compartment (WHC) training schematic includes simple and complex fluid schematics, as well as overall hardware locations. It is used as a teaching aid during WHC lessons for both ISS crew and flight controllers. ISS flight control documentation is used to support all aspects of ISS mission operations. The Quick Look Database and Consolidated Tool Page are imagery-based references used in real-time to help the Operations Support Officer (OSO) find data faster and improve discussions with the Flight Director and Capsule Communicator (CAPCOM). A Quick Look page was created for the Permanent Multipurpose Module (PMM) by locating photos of the module interior, labeling specific hardware, and organizing them in schematic form to match the layout of the PMM interior. A Tool Page was created for the Maintenance Work Area (MWA) by gathering images, detailed drawings, safety information, procedures, certifications, demonstration videos, and general facts of each MWA component and displaying them in an easily accessible and consistent format. Participation in ISS mechanisms and maintenance lessons, mission simulation On-the-Job Training (OJT), and real-time flight OJT was used as an opportunity to train for day-to-day operations as an OSO, as well as learn how to effectively respond to failures and emergencies during mission simulations and real-time flight operations.

  6. Fingerprint authentication via joint transform correlator and its application in remote access control of a 3D microscopic system

    NASA Astrophysics Data System (ADS)

    He, Wenqi; Lai, Hongji; Wang, Meng; Liu, Zeyi; Yin, Yongkai; Peng, Xiang

    2014-05-01

    We present a fingerprint authentication scheme based on the optical joint transform correlator (JTC) and further describe its application to the remote access control of a Network-based Remote Laboratory (NRL). It is built to share a 3D microscopy system of our realistic laboratory in Shenzhen University with the remote co-researchers in Stuttgart University. In this article, we would like to focus on the involved security issues, mainly on the verification of various remote visitors to our NRL. By making use of the JTC-based optical pattern recognition technique as well as the Personal Identification Number (PIN), we are able to achieve the aim of authentication and access control for any remote visitors. Note that only the authorized remote visitors could be guided to the Virtual Network Computer (VNC), a cross-platform software, which allows the remote visitor to access the desktop applications and visually manipulate the instruments of our NRL through the internet. Specifically to say, when a remote visitor attempts to access to our NRL, a PIN is mandatory required in advance, which is followed by fingerprint capturing and verification. Only if both the PIN and the fingerprint are correct, can one be regarded as an authorized visitor, and then he/she would get the authority to visit our NRL by the VNC. It is also worth noting that the aforementioned "two-step verification" strategy could be further applied to verify the identity levels of various remote visitors, and therefore realize the purpose of diversified visitor management.

  7. Clinical utility of far-infrared therapy for improvement of vascular access blood flow and pain control in hemodialysis patients

    PubMed Central

    Choi, Soo Jeong; Cho, Eun Hee; Jo, Hye Min; Min, Changwook; Ji, Young Sok; Park, Moo Yong; Kim, Jin Kuk; Hwang, Seung Duk

    2015-01-01

    Background Maintenance of a well-functioning vascular access and minimal needling pain are important goals for achieving adequate dialysis and improving the quality of life in hemodialysis (HD) patients. Far-infrared (FIR) therapy may improve endothelial function and increase access blood flow (Qa) and patency in HD patients. The aim of this study was to evaluate effects of FIR therapy on Qa and patency, and needling pain in HD patients. Methods This prospective clinical trial enrolled 25 outpatients who maintained HD with arteriovenous fistula. The other 25 patients were matched as control with age, sex, and diabetes. FIR therapy was administered for 40 minutes during HD 3 times/wk and continued for 12 months. The Qa was measured by the ultrasound dilution method, whereas pain was measured by a numeric rating scale at baseline, then once per month. Results One patient was transferred to another facility, and 7 patients stopped FIR therapy because of an increased body temperature and discomfort. FIR therapy improved the needling pain score from 4 to 2 after 1 year. FIR therapy increased the Qa by 3 months and maintained this change until 1 year, whereas control patients showed the decrease in Qa. The 1-year unassisted patency with FIR therapy was not significantly different from control. Conclusion FIR therapy improved needling pain. Although FIR therapy improved Qa, the unassisted patency was not different compared with the control. A larger and multicenter study is needed to evaluate the effect of FIR therapy. PMID:27069856

  8. Shape-Controlled Growth of Carbon Nanostructures: Yield and Mechanism.

    PubMed

    Ma, Yao; Sun, Xiao; Yang, Nianjun; Xia, Junhai; Zhang, Lei; Jiang, Xin

    2015-08-24

    Carbon nanostructures with precisely controlled shapes are difficult materials to synthesize. A facet-selective-catalytic process was thus proposed to synthesize polymer-linked carbon nanostructures with different shapes, covering straight carbon nanofiber, carbon nano Y-junction, carbon nano-hexapus, and carbon nano-octopus. A thermal chemical vapor deposition process was applied to grow these multi-branched carbon nanostructures at temperatures lower than 350 °C. Cu nanoparticles were utilized as the catalyst and acetylene as the reaction gas. The growth of those multi-branched nanostructures was realized through the selective growth of polymer-like sheets on certain indexed facets of Cu catalyst. The vapor-facet-solid (VFS) mechanism, a new growth mode, has been proposed to interpret such a growth in the steps of formation, diffusion, and coupling of carbon-containing oligomers, as well as their final precipitation to form nanostructures on the selective Cu facets.

  9. Bacterial cell curvature through mechanical control of cell growth

    PubMed Central

    Cabeen, Matthew T; Charbon, Godefroid; Vollmer, Waldemar; Born, Petra; Ausmees, Nora; Weibel, Douglas B; Jacobs-Wagner, Christine

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics of cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology. PMID:19279668

  10. A comparison of drive mechanisms for precision motion controlled stages

    SciTech Connect

    Buice, E S; Yang, H; Otten, D; Smith, S T; Hocken, R J; Trumper, D L; Seugling, R M

    2006-03-22

    This abstract presents a comparison of two drive mechanisms, a Rohlix{reg_sign} drive and a polymer nut drive, for precision motion controlled stages. A single-axis long-range stage with a 50 mm traverse combined with a short-range stage with a 16 {micro}m traverse at a operational bandwidth of 2.2 kHz were developed to evaluate the performance of the drives. The polymer nut and Rohlix{reg_sign} drives showed 4 nm RMS and 7 nm RMS positioning capabilities respectively, with traverses of 5 mm at a maximum velocity of 0.15 mm{sup -}s{sup -1} with the short range stage operating at a 2.2 kHz bandwidth. Further results will be presented in the subsequent sections.

  11. Protein synthesis as an integral quality control mechanism during ageing.

    PubMed

    Charmpilas, Nikolaos; Daskalaki, Ioanna; Papandreou, Margarita Elena; Tavernarakis, Nektarios

    2015-09-01

    Ageing is manifested as functional and structural deterioration that affects cell and tissue physiology. mRNA translation is a central cellular process, supplying cells with newly synthesized proteins. Accumulating evidence suggests that alterations in protein synthesis are not merely a corollary but rather a critical factor for the progression of ageing. Here, we survey protein synthesis regulatory mechanisms and focus on the pre-translational regulation of the process exerted by non-coding RNA species, RNA binding proteins and alterations of intrinsic RNA properties. In addition, we discuss the tight relationship between mRNA translation and two central pathways that modulate ageing, namely the insulin/IGF-1 and TOR signalling cascades. A thorough understanding of the complex interplay between protein synthesis regulation and ageing will provide critical insights into the pathogenesis of age-related disorders, associated with impaired proteostasis and protein quality control.

  12. Wireless digital-ultrasonic sensors for proximity ID, access control, firearm control, and C3I in homeland security and law enforcement applications

    NASA Astrophysics Data System (ADS)

    Forcier, Bob

    2003-09-01

    This paper describes a new patent-pending digital-ultrasonic sensor network technology, which provides a "security protection sphere" around the authorized user(s) and the infrastructure system or system(s) to achieve C3I in Homeland Security and Law Enforcement Applications. If the system device, such as a firearm, a secure computer, PDA, or vehicle is misplaced, stolen or removed from the security protective sphere, an alarm is activated. A digital-ultrasonic sensor/tag utilizes the system"s physical structure to form a 2 to 20 Meter programmable protection sphere around the device and the authorized user. In addition, the system allows only authorized users to utilize the system, thereby creating personalized weapons, secure vehicle access or secure computer hardware. If an unauthorized individual accesses the system device, the system becomes inoperative and an alarm is activated. As the command and control, the authorized individual is provided a secure wristwatch/PDA. Access control is provided by "touch" and is controlled through the wristwatch/PDA/smartcard with a unique digital-ultrasonic coding and matching protocol that provides a very high level of security for each wireless sensor.

  13. Mechanisms Controlling Virulence Thresholds of Mixed Viral Populations ▿

    PubMed Central

    Lancaster, Karen Z.; Pfeiffer, Julie K.

    2011-01-01

    The propensity of RNA viruses to revert attenuating mutations contributes to disease and complicates vaccine development. Despite the presence of virulent revertant viruses in some live-attenuated vaccines, disease from vaccination is rare. This suggests that in mixed viral populations, attenuated viruses may limit the pathogenesis of virulent viruses, thus establishing a virulence threshold. Here we examined virulence thresholds using mixtures of virulent and attenuated viruses in a transgenic mouse model of poliovirus infection. We determined that a 1,000-fold excess of the attenuated Sabin strain of poliovirus was protective against disease induced by the virulent Mahoney strain. Protection was induced locally, and inactivated virus conferred protection. Treatment with a poliovirus receptor-blocking antibody phenocopied the protective effect of inactivated viruses in vitro and in vivo, suggesting that one mechanism controlling virulence thresholds may be competition for a viral receptor. Additionally, the type I interferon response reduces poliovirus pathogenesis; therefore, we examined virulence thresholds in mice lacking the alpha/beta interferon receptor. We found that the attenuated virus was virulent in immunodeficient mice due to the enhanced replication and reversion of attenuating mutations. Therefore, while the type I interferon response limits the virulence of the attenuated strain by reducing replication, protection from disease conferred by the attenuated strain in immunocompetent mice can occur independently of replication. Our results identified mechanisms controlling the virulence of mixed viral populations and indicate that live-attenuated vaccines containing virulent virus may be safe, as long as virulent viruses are present at levels below a critical threshold. PMID:21795346

  14. Mitochondria-controlled signaling mechanisms of brain protection in hypoxia

    PubMed Central

    Lukyanova, Ludmila D.; Kirova, Yulia I.

    2015-01-01

    The article is focused on the role of the cell bioenergetic apparatus, mitochondria, involved in development of immediate and delayed molecular mechanisms for adaptation to hypoxic stress in brain cortex. Hypoxia induces reprogramming of respiratory chain function and switching from oxidation of NAD-related substrates (complex I) to succinate oxidation (complex II). Transient, reversible, compensatory activation of respiratory chain complex II is a major mechanism of immediate adaptation to hypoxia necessary for (1) succinate-related energy synthesis in the conditions of oxygen deficiency and formation of urgent resistance in the body; (2) succinate-related stabilization of HIF-1α and initiation of its transcriptional activity related with formation of long-term adaptation; (3) succinate-related activation of the succinate-specific receptor, GPR91. This mechanism participates in at least four critical regulatory functions: (1) sensor function related with changes in kinetic properties of complex I and complex II in response to a gradual decrease in ambient oxygen concentration; this function is designed for selection of the most efficient pathway for energy substrate oxidation in hypoxia; (2) compensatory function focused on formation of immediate adaptive responses to hypoxia and hypoxic resistance of the body; (3) transcriptional function focused on activated synthesis of HIF-1 and the genes providing long-term adaptation to low pO2; (4) receptor function, which reflects participation of mitochondria in the intercellular signaling system via the succinate-dependent receptor, GPR91. In all cases, the desired result is achieved by activation of the succinate-dependent oxidation pathway, which allows considering succinate as a signaling molecule. Patterns of mitochondria-controlled activation of GPR-91- and HIF-1-dependent reaction were considered, and a possibility of their participation in cellular-intercellular-systemic interactions in hypoxia and adaptation was

  15. Passive Flow Separation Control Mechanism Inspired by Shark Skin

    NASA Astrophysics Data System (ADS)

    Oakley, India; Lang, Amy

    2015-11-01

    The following experimental work seeks to examine shark scales as passive flow-actuated separation control mechanisms. It is hypothesized that the actuation of these scales can in fact reduce pressure drag by inhibiting flow reversal and thereby prevent flow separation. In order to examine this mechanism at a fundamental level, three-dimensional sharkskin scales were simplified and modeled as two-dimensional flaps. To further simplify the experiment, the flaps were observed within a laminar boundary layer. The laminar boundary layer was grown over a long flat plate that was placed inside a water tunnel. A rotating cylinder was also used to induce an unsteady, increasing adverse pressure gradient, which generated a reversing flow. In order to visualize the potential actuation of the two-dimensional flaps DPIV (digital particle image velocimetry) was utilized. Three main objectives for this work included, the actuation of the two-dimensional flaps, the resistance to a reversed flow as a result of flap actuation and the prevention of flow separation. However once the experiment was conducted the flaps did not perform as previously hypothesized. The adverse pressure gradient induced by the rotating cylinder did not produce a reversing flow powerful enough to actuate the flaps. NSF REU Site Award 1358991.

  16. Lattice Metamaterials with Mechanically Tunable Poisson's Ratio for Vibration Control

    NASA Astrophysics Data System (ADS)

    Chen, Yanyu; Li, Tiantian; Scarpa, Fabrizio; Wang, Lifeng

    2017-02-01

    Metamaterials with artificially designed architectures are increasingly considered as new paradigmatic material systems with unusual physical properties. Here, we report a class of architected lattice metamaterials with mechanically tunable negative Poisson's ratios and vibration-mitigation capability. The proposed lattice metamaterials are built by replacing regular straight beams with sinusoidally shaped ones, which are highly stretchable under uniaxial tension. Our experimental and numerical results indicate that the proposed lattices exhibit extreme Poisson's-ratio variations between -0.7 and 0.5 over large tensile deformations up to 50%. This large variation of Poisson's-ratio values is attributed to the deformation pattern switching from bending to stretching within the sinusoidally shaped beams. The interplay between the multiscale (ligament and cell) architecture and wave propagation also enables remarkable broadband vibration-mitigation capability of the lattice metamaterials, which can be dynamically tuned by an external mechanical stimulus. The material design strategy provides insights into the development of classes of architected metamaterials with potential applications including energy absorption, tunable acoustics, vibration control, responsive devices, soft robotics, and stretchable electronics.

  17. Cellular and Humoral Mechanisms Involved in the Control of Tuberculosis

    PubMed Central

    Zuñiga, Joaquin; Torres-García, Diana; Santos-Mendoza, Teresa; Rodriguez-Reyna, Tatiana S.; Granados, Julio; Yunis, Edmond J.

    2012-01-01

    Mycobacterium tuberculosis (Mtb) infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs). We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB. PMID:22666281

  18. Unconventional mechanisms control cyclic respiratory gas release in flying Drosophila.

    PubMed

    Lehmann, Fritz-Olaf; Heymann, Nicole

    2005-10-01

    The high power output of flight muscles places special demands on the respiratory gas exchange system in insects. In small insects, respiration relies on diffusion, and for elevated locomotor performance such as flight, instantaneous gas exchange rates typically co-vary with the animal's metabolic activity. By contrast, under certain conditions, instantaneous release rate of carbon dioxide from the fruit fly Drosophila flying in a virtual-reality flight arena may oscillate distinctly at low frequency (0.37+/-0.055 Hz), even though flight muscle mechanical power output requires constant metabolic activity. Cross-correlation analysis suggests that this uncoupling between respiratory and metabolic rate is not driven by conventional types of convective flow reinforcement such as abdominal pumping, but might result from two unusual mechanisms for tracheal breathing. Simplified analytical modeling of diffusive tracheal gas exchange suggests that cyclic release patterns in the insect occur as a consequence of the stochastically synchronized control of spiracle opening area by the four large thoracic spiracles. Alternatively, in-flight motion analysis of the abdomen and proboscis using infra-red video imaging suggests utilization of the proboscis extension reflex (PER) for tracheal convection. Although the respiratory benefit of synchronized spiracle opening activity in the fruit fly is unclear, proboscis-induced tracheal convection might potentially help to balance the local oxygen supply between different body compartments of the flying animal.

  19. Internal Control Rod Drive Mechanisms, Design Options for IRIS

    SciTech Connect

    Conway, Lawrence E.; Petrovic, Bojan

    2004-07-01

    IRIS (International Reactor Innovative and Secure) is a medium-power (335 MWe) PWR with an integral, primary circuit configuration, where all the reactor coolant system components are contained within the reactor vessel. This integral configuration is a key reason for the success of IRIS' 'safety-by-design' approach, whereby accident initiators are eliminated or the accident consequences and/or frequency are reduced. The most obvious example of the IRIS safety by design approach is the elimination of large LOCA's, since the integral reactor coolant system has no large loop piping. Another serious accident scenario that is being addressed in IRIS is the postulated ejection of a reactor control cluster assembly (RCCA). This accident initiator can be eliminated by locating the RCCA drive mechanisms (CRDMs) inside the reactor vessel. This eliminates the mechanical drive rod penetration between the RCCA and the external CRDM, eliminating the potential for differential pressure across the pressure boundary, and thus eliminating 'by design' the possibility for rod ejection accident. Moreover, the elimination of the 'large' drive-rod penetrations and the external CRDM pressure housings decreases the likelihood of boric acid leakage and subsequent corrosion of the reactor pressure boundary (like the Davis-Besse incident). This paper will discuss the IRIS top level design requirements and objectives for internal CRDMs, and provide examples candidate designs and their specific performance characteristics. (authors)

  20. Quality Control Review of Air Force Audit Agency’s Special Access Program Audits

    DTIC Science & Technology

    2014-12-09

    external quality control review of the AFAA SAP audits in conjunction with the Army Audit Agency’s review of the AFAA non- SAP audits. We conducted this...provide reasonable assurance of meeting the objectives of quality control. We tested the AFAA SAP system of quality control for audits to the extent...control for the audit function of AFAA SAP in effect for the period ended September 30, 2013, was designed in accordance with quality standards