Vignette d'image

Kropf, Peter

Nom
Kropf, Peter
Affiliation principale
Fonction
Professeur ordinaire
Email
peter.kropf@unine.ch

Résultat de la recherche

Filtres

1163
10214
Réinitialiser les filtres

Paramètres

Voici les éléments 1 - 10 sur 116
  • Publication
    Métadonnées seulement
    A Communication Framework Towards Flexible Associations of Business Entities Within Evolving Environments
    (: Springer Verlag, 2003)
    Ludolph, Hendrik
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    The Internet and electronic commerce have become indispensable for many of us. To adequately use the increasing amount of data available, attempts are made to extend data processing from a lexical view towards a multi-level view, including meaning and/or context (e.g., DAML, Web Services). The goal of this paper is to introduce a formal framework, which models communications from such a multi-level perspective. Therein, we discuss fundamental ideas of communication, such as agents involved and their respective structure. We integrate the concept of an agent’s adaptive behaviour in order to assure a high degree of understanding. The framework is illustrated using a practical example to depict its usefulness and how it may be further developed.
  • Publication
    Métadonnées seulement
    A collaborative extension of a visualization system
    (: IEEE, 2005)
    Casera, Steve
    ;
    Nägeli, Hans-Heinrich 
    ;
    Kropf, Peter 
    This paper presents an extension of the single-user scientific visualization system ZoomIn to a collaborative system. We discuss the principal challenges of remote collaboration in the case of scientific visualization and present the solutions realized for ZoomIn. The main issues identified include the support of slow/fast network connections, portability, ease-of-use, privacy, configuration of the working mode and permissions. We describe why the main concepts of the original ZoomIn are well suited for a collaborative extension and how collaboration is introduced. In particular, the volume of data for scientific visualization may be very large. Therefore, the transfer of data has to be optimized. We present three different methods of data transfer for collaborative visualization and compare their efficiency with respect to particular application scenarios.
  • Publication
    Métadonnées seulement
    Shibboleth based Authentication, Authorization, Accounting and Auditing in Wireless Mesh Networks
    (: IEEE, 2011-10-22)
    Schiller, Eryk 
    ;
    Monakhov, Alexey 
    ;
    Kropf, Peter 
    We present the basic architectural elements of the Captive Portal integrating Shibboleth based Authentication, Authorization, Accounting and Auditing into Wireless Mesh Networks. The Captive Portal is built upon the SWITCHaai/Shibboleth architecture especially designed to protect web based services. The architecture is secure, eavesdropping protected and does not require any specialized software installation on the client side.
  • Publication
    Métadonnées seulement
    Appropriately placed surface EMG electrodes reflect deep muscle activity (psoas, quadratus lumborum, abdominal wall) in the lumbar spine
    (1996-1-22)
    McGill, Stuart
    ;
    Juker, Daniel
    ;
    Kropf, Peter 
    This study tested the possibility of obtaining the activity of deeper muscles in the torso-specifically psoas, quadratus lumborum, external oblique, internal oblique and transverse abdominis, using surfce myoelectric electrodes. It was hypothesized that: (1) surface electrodes adequately represent the amplitude of deep muscles (specifically psoas, quadratus lumborum, external oblique, internal oblique, transverse abdominis); (2) a single surface electrode location would best represent the activation profiles of each deep muscle over a broad variety of tasks. We assumed that prediction of activation within 10% of maximum voluntary contraction (RMS difference between the surface and intramuscular channels), over the time history of the signal, was reasonable and acceptable to assist clinical interpretation of muscle activation amplitude, and ultimately for modeled estimates of muscle force. Surface electrodes were applied and intramuscular electrodes were inserted on the left side of the body in five men and three women who then performed a wide variety of flexor tasks (bent knee and straight leg situps and leg raises, curl ups), extensor tasks (including lifting barbells up to 70 kg), lateral bending tasks (standing lateral bend and horizontal lying side support), twisting tasks (standing and sitting), and internal/external hip rotation. Using the criteria of RMS difference and the coefficient of determination (R(2)) to compare surface with intramuscular myoelectric signals, the results indicated that selected surface electrodes adequately represent the amplitude of deep muscles-always within 15% RMS difference, or less with the exception of psoas where differences up to 20% were observed but only in certain maximum voluntary contraction efforts. It appears reasonable for spine modelers, and particularly clinicians, to assume well selected surface electrode locations provide a representation of these deeper muscles - as long as they recognize the magnitude of error for their particular application. Copyright (C) 1996 Elsevier Science Ltd.
  • Publication
    Métadonnées seulement
    Experimenting with gnutella communities
    (: Springer-Verlag Berlin, 2002)
    Vaucher, Jean
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    ;
    Jouve, Thierry
    ;
    Plaice, John
    ;
    Kropf, Peter 
    ;
    Schulthess, Peter
    ;
    Slonim, Jacob
    Computer networks or distributed systems in general may be regarded as communities where the individual components, be they entire systems, application software or users, interact in a shared environment. Such communities dynamically evolve with components or nodes joining and leaving the system. Their own individual activities affect the community's behavior and vice versa. This paper discusses various practical experiments undertaken to investigate the behavior of a real system, the Gnutella network, which represents such a community. Gnutella is a distributed Peer-to-Peer data-sharing system without any central control. It turns out that most interactions between nodes do not last long and much of their activity is devoted to finding appropriate partners in the network. The experimental results presented have been obtained from a Java implementation of Gnutella running in the open Internet environment, and thus in unknown and quickly changing network structures heavily depending on chance.
  • Publication
    Métadonnées seulement
    LoDACE: une architecture de partage de charge dans les systèmes distribués objet
    (1998)
    Badidi, Elarbi
    ;
    Keller, Rudolf
    ;
    Kropf, Peter 
    ;
    Van Dongen, Vincent
  • Publication
    Métadonnées seulement
    Coordinating Plans for Agents Performing AAW Hardkill and Softkill for Frigates
    (2001)
    Chaib-draa, Brahim
    ;
    Blodgett, Dale
    ;
    Kropf, Peter 
    The coordination of anti-air warfare (AAW) hardkill (HK) and softkill (SK) weapon systems is an important aspect of command and control for the HALIFAX Class Frigate. This led to the development of a rapid prototyping environment, described here, which supports the investigation of methods to coordinate the plans produced by AAW HK and SK agents. The HK and SK planning agents are described. An overview of agent coordination methods is provided, with a focus on our initial approach to HK and SK coordination via a Central Coordinator. This approach was successfully implemented, and proved effective in mitigating interference between HK and SK actions, and improved the overall survivability of the Frigate. Finally, future directions of this research are presented.
  • Publication
    Accès libre
    Intensional objects
    (1999)
    Kropf, Peter 
    ;
    Plaice, John
    We summarize the interaction between the theory behind intensional programming, as seen in Lucid; and intensional versioning, as seen in Lemur, Intensional HTML, ISE, VMAKE, etc. These two concepts can be seen to be duals of each other, and they rely on dual notions of store, the warehouse for caching values, and the catalog for providing definitions. Catalogs contain intensional objects, which are openable boxes labelled by Lucid contexts. Finally, Lucid contexts are now first-class values.
  • Publication
    Métadonnées seulement
    Networking and computing: from the chip to the web
    (1996)
    Kropf, Peter 
    ;
    Plaice, John
    There are two fundamental trends in the development of computers: the miniaturization of components and the increase in communication capacities. The combination of these two trends is leading to a qualitatively new situation, in which the same techniques will be appli- cable at all scales of computing, be they at the chip level or at the level of the World Wide Web (WWW).
  • Publication
    Métadonnées seulement