411,333 research outputs found
Pilot decision making in a computer-aided flight management situation
An experimental representation of a computer-aided multi-task flight management situation has been developed. A computer aiding program was implemented to serve as a back-up decision maker. An experiment was conducted with a balanced design of several subject runs for different workload levels. This was achieved using three levels of subsystem event arrival rates, three levels of control task involvement, and three levels of availability of computer aiding. Experimental results compared quite favorably with those from a computer simulation which employed a queueing model. It was shown that the aiding had enhanced system performance as well as subjective ratings, and that the adaptive aiding policy further reduced subsystem delay
Process Management in Distributed Operating Systems
As part of designing and building the Amoeba distributed operating system, we have come up with a simple set of mechanisms for process management that allows downloading process migration, checkpointing, remote debugging and emulation of alien operating system interfaces.\ud
The basic process management facilities are realized by the Amoeba Kernel and can be augmented by user-space services: Debug Service, Load-Balancing Service, Unix-Emulation Service, Checkpoint Service, etc.\ud
The Amoeba Kernel can produce a representation of the state of a process which can be given to another Kernel where it is accepted for continued execution. This state consists of the memory contents in the form of a collection of segments, and a Process Descriptor which contains the additional state, program counters, stack pointers, system call state, etc.\ud
Careful separation of mechanism and policy has resulted in a compact set of Kernel operations for process creation and management. A collection of user-space services provides process management policies and a simple interface for application programs.\ud
In this paper we shall describe the mechanisms as they are being implemented in the Amoeba Distributed System at the Centre for Mathematics and Computer Science in Amsterdam. We believe that the mechanisms described here can also apply to other distributed systems
Policy capturing and two level specifications of policies for human and software processing
In recent few years, the use of "policies" in the management of the behavior of large-scale, dynamic or distributed systems is gaining importance. In the policy research area, how to capture policies is the first problem scientists need to solve. Policies can be specified in three ways: a Policy Definition Language (PDL), a formal logic-based policy representation language or an informal natural language. Generally, an editor and a policy management tool are used to input these specifications. Because both the PDLs and the formal logic-based policy representation languages are very complex and more suitable for machine communication instead of human communication, their usages are limited to a small group of professional people. In this thesis, two levels of policy specifications are introduced. A Restricted Natural Language (RNL), as the high-level policy specification, is used for human-computer interactions. Compared to the PDLs and the formal logic-based policy representation languages, the RNL is both easy to use and easy to learn. It enables a wider group of end users, especially the novice users, to participate in stating the policies. A logic-based formal representation, as the low-level policy specification, is then used for further machine-oriented processing in policy-based systems. A methodology of how to construct such a RNL is also presented and the methodology is applied to two different cases. In the implementation part of the thesis, a RNL user interface (RNLI) named the Virtual Thesis Office (VTO) System is also developed and presente
A Crowdsourcing Approach to Identify Common Method Bias and Self-Representation
Pertinent questions on the measurement of social indicators are: the verification of data gained online (e.g., controlling for self-representation on social networks), and appropriate uses in community management and policy-making. Across platforms like Facebook, LinkedIn, Twitter, and blogging services, users (sub)consciously represent themselves in a way which is appropriate for their intended audience (Qui et al., 2012; Zhao et al., 2008). However, scholars in the social sciences and computer science have not yet adequately addressed controlling for self-representation, or the propensity to display or censor oneself, in their analyses (Zhao et al., 2008; Das and Kramer, 2013). As such researchers on these platforms risk working with āgamifiedā, socially responding, or online disinhibitive (trolls) personas which goes above and beyond efforts to contain Common Method Biases (CMB) (Linville, 1985; Suler, 2004; Podsakoff et al., 2003). What has not been approached in a systematic way is the verification of such data on offline and actual personality. In this paper, we focus on the alignment of traditional survey methods with unobtrusive methods to gather profile data from online social media via crowdsourcing platforms
ESPOON: Enforcing Encrypted Security Policies in Outsourced Environments
The enforcement of security policies in outsourced environments is still an
open challenge for policy-based systems. On the one hand, taking the
appropriate security decision requires access to the policies. However, if such
access is allowed in an untrusted environment then confidential information
might be leaked by the policies. Current solutions are based on cryptographic
operations that embed security policies with the security mechanism. Therefore,
the enforcement of such policies is performed by allowing the authorised
parties to access the appropriate keys. We believe that such solutions are far
too rigid because they strictly intertwine authorisation policies with the
enforcing mechanism.
In this paper, we want to address the issue of enforcing security policies in
an untrusted environment while protecting the policy confidentiality. Our
solution ESPOON is aiming at providing a clear separation between security
policies and the enforcement mechanism. However, the enforcement mechanism
should learn as less as possible about both the policies and the requester
attributes.Comment: The final version of this paper has been published at ARES 201
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Knowledge Cartography: Software tools and mapping techniques
Knowledge Cartography is the discipline of mapping intellectual landscapes.The focus of this book is on the process by which manually crafting interactive, hypertextual maps clarifies oneās own understanding, as well as communicating it.The authors see mapping software as a set of visual tools for reading and writing in a networked age. In an information ocean, the primary challenge is to find meaningful patterns around which we can weave plausible narratives. Maps of concepts, discussions and arguments make the connections between ideas tangible and disputable.
With 17 chapters from the leading researchers and practitioners, the reader will find the current stateāof-the-art in the field. Part 1 focuses on educational applications in schools and universities, before Part 2 turns to applications in professional communitie
Smart objects as building blocks for the internet of things
The combination of the Internet and emerging technologies such as nearfield communications, real-time localization, and embedded sensors lets us transform everyday objects into smart objects that can understand and react to their environment. Such objects are building blocks for the Internet of Things and enable novel computing applications. As a step toward design and architectural principles for smart objects, the authors introduce a hierarchy of architectures with increasing levels of real-world awareness and interactivity. In particular, they describe activity-, policy-, and process-aware smart objects and demonstrate how the respective architectural abstractions support increasingly complex application
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