External Request Research Articles

A Role Engineering Framework to Support Dynamic Authorizations in Collaborative Environments

ABSTRACT With the increasing availability of networks and the advancements in their underlying infrastructure of mobile devices, access control and authorization issues will be enablers of future technologies in collaborative environments. Recent works demonstrate efforts to dynamically authorize users without prior knowledge and with no security configuration attributes or roles previously assigned to them. Moreover, current role-based engineering approaches construct role hierarchies without reflecting the organizational structure, since they do not take into account structural organizational characteristics. In this paper we propose an innovative role structure, not solely dependent on naming methods but also that takes into account organizational as well as functional characteristics to provide a practical role assignment methodology between organizations in a collaborative environment. More specifically, we argue that beyond the fact that a role represents a job assignment to perform certain function(s), it is also a composite element representing several organizational characteristics such as organizational function, organizational domain and level of authority. The proposed role structure enables role-to-role assignment as external nonlocal users request access in a particular information system (e.g., people on the move, users logged in from a collaborative organization) and acquire local role(s). A clear advantage in the proposed framework is its flexibility in the role assignment process, since the proposed role decomposition does not require an exact match of predefined credentials. The methodology is autonomous, as no prior trust establishment is required between interactive organizations, expendable as new organizations can join the collaboration without affecting the existing ones, flexible as it does not affect the local access control policy, scalable as the collaboration can increase arbitrary and efficient as the comparison methodology guarantees the selection of the appropriate local role, if such one exists.

Wake-Up-Receiver Concepts - Capabilities and Limitations

A promising idea for optimising the power consumption of mobile communication devices represents the usage of an additional ultra-low-power receiver unit, which is able to control the main transceiver in order to reduce the standby power consumption of the overall system. Such a Wake-Up-Receiver (WuRx) unit senses the medium and switches on the communication interfaces in case of an external request. Otherwise, all system components for the network communication are completely switched off. Especially in the domain of resource-limited and embedded devices, WuRx technologies enable novel communication paradigms. But on the application layer, not all scenarios allow the efficient usage of such WuRx technologies. Dependent on environmental parameters, technological limitations and conceptual requirements, different strategies are necessary to ensure energy-efficient system operation. In this article, we present a critical analysis of the capabilities and the conceptual limitations of WuRx approaches. Therefore, we identify critical parameters for WuRx concepts, which limit the efficiency in real world scenarios. Our goal is to classify sufficient fields of application. Furthermore we evaluate the influences of these parameters on the system behaviour. In addition, we introduce heterogeneous energy harvesting approaches as an efficient way for the system optimisation. The proposed technologies are capable to be integrated into small-sized wireless sensor platforms and prolong the system uptime significantly. The presented simulation results are focusing on actual smart metering scenarios and wireless sensor networks. Based on these measurements, we were able to apply further optimisation steps within the system configuration on the application layer. In this context, we focus on application-specific key issues, like the trade-off between measurement quality and quantity, the usage of data buffering approaches and QoS capabilities.

Development of General Embedded Intelligent Monitoring System for Tower Crane

Development of General Embedded Intelligent Monitoring System for Tower Crane

A Fully Characterizable Asynchronous Multiphase Delay Generator

A fully characterizable, 128-stage asynchronous Multiphase Delay Generator (MDG) integrated in standard 0.35 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu{\hbox {m}}$</tex></formula> CMOS technology is presented. The circuit consists of a mirror Voltage-Controlled Delay Line (VCDL), driven by a Delay-Locked Loop (DLL), and an analog memory block. The master DLL ensures the stability over temperature and the absolute precision of the delay, whereas the mirror VCDL allows an asynchronous operation of the MDG with respect to the DLL reference clock. The memory block carries out a precise stage-to-stage delay and jitter characterization by analog sampling the state of the mirror VCDL upon an external request. Two versions of the circuit differing by their VCDL layout configurations were processed in order to compare their absolute time accuracy and jitter performance. In the first variant the two delay lines were laid out in an interlaced arrangement, whereas in the second, the mirror VCDL was positioned under the master VCDL. A maximal temporal dynamic range of 125 ps–1 ns was achieved. The single-stage delay variation with temperature was less than 1% over the 10–60 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}{\hbox {C}}$</tex></formula> range considered. The mean RMS jitter level per stage remained below 3% of the elementary delay over the entire dynamic range of the MDG for both circuit versions.

Enhancing Self‐Referencing to Health Messages

A mediation model in which internal and external request tactics enhances the perceived effectiveness of a public health messages by increasing self‐referencing, but only for persons concerned about the targeted health issue. For those concerned about hepatitis B (but not for those who are not concerned), using second‐person pronouns rather than third‐person terms (an internal request tactic) and using rhetorical questions rather than declarative statements in the ad headings (an external request tactic) enhance perceived message effectiveness. As expected, both processes are mediated by increased self‐referencing.

Thermal analysis of Stirling engine solar driven

Solar energy is one of the more attractive renewable energy sources; the conversion of the latter per thermal way into electricity is a major energy stake. The current systems are primarily based on technology known as ‘solar dish/Stirling’, which uses Stirling engines placed at the focal plan of a parabolic concentrator. The Stirling engine presents an excellent theoretical output equivalent to the output of Carnot one. It is with external combustion, less pollutant, silencer and request little maintenance. Thanks to these advantages which the Stirling engine is very interesting to study. The dish Stirling system studies consist on three parts; the thermal modelling of Stirling engine, optical study of parabolic concentrator and finally the thermal study of the receiver. The present study is dedicated only to a thermal modelling of the Stirling engine based on the decoupled method. We evaluate, starting from an ideal adiabatic analysis, the thermal and mechanical powers exchanged, that we correct then by calculating the various losses within the machine. This model led to the writing of important set of equations algebra - differentials. The calculation programme worked out under Fortran to solve this system, makes allow to calculate the performances of any types of the Stirling engines, according to the kinematics used, the types of regenerators, the exchangers, as well as the various working liquids used.

Production and Evaluation of Requests by Right Hemisphere Brain-Damaged Individuals

Several researchers have investigated the comprehension of "indirect requests" by fight hemisphere brain-damaged (RHD) individuals. Until the present, however, no sound description of the phenomenon under investigation has been reached and explanatory attempts of the observed behavior are diverse. Based on a theoretical framework issued from studies in cross-cultural pragmatics, the present study is an attempt to provide a systematic description of the production of request sequences and the evaluation of direct and nonconventionally indirect requests by RHD patients. The analyses of the production data showed that, relative to the control group, the RHD patients behaved differently concerning the application of nonconventionally indirect requests, the use of external request modifiers, the evaluation of nonconventionally indirect requests, and the use of propositions. No differences in production performance were observed with regard to direct requests, conventionally indirect requests, and internal request modifiers. Further, the RHD group and the control group behaved similarly in evaluating direct requests. The results are discussed in relation to previous findings and a mental model approach is proposed as an explanatory framework. The findings suggest that the RHD patients were able to build a mental representation at a text level and a situational level but may have had problems within the realm of monitoring or planning integration processes if more than one mental model is involved. There is some indication that attention and visuospatial abilities may have influenced the verbal and evaluation abilities of the RHD subjects. It seems a worthy endeavor to pursue this issue in future research.

A RAM architecture for concurrent access and on chip testing

A novel RAM architecture supporting concurrent memory access and on chip testing (CMAT) is proposed. A large-capacity memory chip is decomposed into test neighborhoods (TNDs), each of which is tested independently. When there are data stored in a TND, the data are saved into a buffer before testing the TND, and the TND's contents are restored using buffered data after testing the TND. If an external request is not made to the TND, the request can be directed to the addressed memory cells. Otherwise, the buffered data can be loaded back into the TND, or the request is detoured to a corresponding buffer. By deriving an analytical model, the performance penalty and hardware overhead of the CMAT architecture are shown to be very small. >