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Kropf, Peter

Nom
Kropf, Peter
Affiliation principale
Fonction
Professeur ordinaire
Email
peter.kropf@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/221

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  • Publication
    Métadonnées seulement
    A LRAAM-based Partial Order Function for Ontology Matching in the Context of Service Discovery
    (2017-6-14)
    Ludolph, Hendrik
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    The demand for Software as a Service is heavily increasing in the era of Cloud. With this demand comes a proliferation of third-party service offerings to fulfill it. It thus becomes crucial for organizations to find and select the right services to be integrated into their existing tool landscapes. Ideally, this is done automatically and continuously. The objective is to always provide the best possible support to changing business needs. In this paper, we explore an artificial neural network implementation, an LRAAM, as the specific oracle to control the selection process. We implemented a proof of concept and conducted experiments to explore the validity of the approach. We show that our implementation of the LRAAM performs correctly under specific parameters. We also identify limitations in using LRAAM in this context.
  • Publication
    Métadonnées seulement
    Managing traffic in peer-to-peer networks: the token-web protocol
    (: Society for Modeling & Simulation International, 2011-1-22)
    Babin, Gilbert
    ;
    Kropf, Peter 
    ;
    Dormann, Silvia
    We distinguish two types of P2P protocols: structured protocols, which use a directed search approach, and unstructured protocols, which use a flooding approach. We propose the Token-Web as a new type of P2P, semi-structured protocols, that combines directed search and controlled flooding. The protocol presumes that most participants are trustworthy and therefore it does not require authentification. However, mechanisms to prevent disruption are set in place. In this paper, we describe the Token-Web and present results of experiments conducted to assess its properties in a simulated environment and on PlanetLab. The results obtained show that the number of tokens tends to stabilize over time, the message drop rate depends on the level of activity in the network, and the query success rate is dependent on the popularity of the resource sought.
  • Publication
    Accès libre
    SoftwIre Integration - An Onto-Neural Perspective
    (: Springer, 2011-1-22)
    Ludolph, Hendrik
    ;
    Kropf, Peter 
    ;
    Babin, Gilbert
    We propose a framework for automated point-to-point application integration. Functional and technical aspects to consider are presented. We advocate using intelligible (ontological) and distributed (neural networks) knowledge representations to guide design and implementation of application interfaces. We believe this yields benefits over manual approaches currently used, in which business specifications are first captured, then translated into technical specifications, and finally implemented, often by costly third-party integration specialists. The present work initiates research efforts towards automation of the latter two activities, with a potential impact on professional-services costs and time-to-operation.
  • Publication
    Accès libre
    Application layer traffic analysis of a Peer-to-Peer system
    (2008)
    Tutsch, Dietmar
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Self-similar or multifractal behavior has been observed for LAN and Internet WAN (backbone) traffic. Investigations about this kind of behavior for application level protocols are rarely found because sessions or even applications are usually too short to be characterized in this direction. Only Telnet and FTP were examined so far. This paper analyzes the traffic shape of Peer-to-Peer (P2P) networks using the Gnutella protocol. Data was collected using a modified LimeWire servent. Self-similarity was estimated using a variance-time plot. The results show that Gnutella messages exhibit a self-similar shape, regardless of the message type.
  • Publication
    Métadonnées seulement
    Application-layer traffic analysis of a peer-to-peer system
    (2008)
    Tutsch, Dietmar
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Characterizing traffic behavior helps to optimize the network architecture for improved performance. Using a modified LimeWire servent ( for both the server and client) and a variance-time plot for traffic characterization, the authors analyze the Gnutella protocol's traffic shape and find that the messages exhibit a self-similar shape. This result shows network designers that they need to consider the self-similar traffic shape in their set-up - for instance, by introducing appropriate buffer sizes.
  • Publication
    Métadonnées seulement
    BALLS: a structured peer-to-peer system with integrated load balancing
    (2006-12-1)
    Le, Viet Dung
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Load balancing is an important problem for structured peer-to-peer systems. We are particularly interested in the consumption of network bandwidth for routing traffic and in the usage of computer resources for object storage. In this paper, we investigate the possibility to simultaneously balance these two types of load. We present a structured peer-to-peer overlay that efficiently performs such simultaneous load balancing. The overlay is constructed by partitioning the nodes of a de Bruijn graph and by allocating the partitions to the peers. Peers balance network bandwidth consumption by repartitioning the nodes. Balancing of computer resources for storage is enabled by dissociating the actual storage location of an object from the location of its search key. The paper presents and analyzes the protocols required to maintain the overlay structure and perform load balancing. We demonstrate their efficiency by simulation. We also compare our proposed overlay network with other approaches.
  • Publication
    Accès libre
    A Structured Peer-to-Peer System with Integrated Index and Storage Load Balancing
    (2006)
    Le, Viet-Dung
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Load balancing emerges as an important problem that affects the performance of structured peer-to-peer systems. This paper presents a peer-to-peer system relying on the partitionning of a de Bruijn graph. The proposed system integrates mechanisms that perform index and storage load balancing. Index load refers to the network traffic incurred by a peer in managing an object index, while storage load refers to the storage space and network traffic required to store objects. The proposed mechanisms allow to effectively distribute both index load and storage load according to the peers’ capacities.
  • Publication
    Métadonnées seulement
    Balls simulator: Evaluator of a structured peer-to-peer system with integrated load balancing
    (2006)
    Le, Viet Dung
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Simulation is an efficient way to evaluate new peer-to-peer models. It requires two implicit properties: large scale and high dynamicity. In the context of our work that proposes a peer-to-peer structure based on partitioning a de Bruijn graph and its load balancing algorithms, we developed a simulator for evaluation purposes. This paper introduces a three- layer architecture of the simulator. This architecture allows to support simulations in two modes: centralized (where all peers are simulated on one physical machine) and decentralized (where the peers run on separate machines communicating through the underlying network).
  • Publication
    Accès libre
    BALLS Simulator : Evaluator of a structured Peer-to-Peer system with integrated load balancing
    (2006)
    Le, Viet-Dung
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    Simulation is an efficient way to evaluate new peer-to-peer models. It requires two implicit properties: large scale and high dynamicity. In the context of our work that proposes a peer-to-peer structure based on partitioning a de Bruijn graph and its load balancing algorithms, we developed a simulator for evaluation purposes. This paper introduces a three- layer architecture of the simulator. This architecture allows to support simulations in two modes: centralized (where all peers are simulated on one physical machine) and decentralized (where the peers run on separate machines communicating through the underlying network).
  • Publication
    Accès libre
    BALLS: A structured Peer-to-Peer system with integrated load balancing
    (2006)
    Le, Viet-Dung
    ;
    Babin, Gilbert
    ;
    Kropf, Peter 
    L'équilibrage de charge est un problème majeur des systèmes pair-à-pair structurés. Nous nous intéressons plus particulièrement à l'utilisation de la bande passante pour le routage de messages et à l'utilisation des ressources informatiques pour le stockage d'objets. Dans cet article, nous présentons un réseau pair-à-pair structuré permettant l'équilibrage efficace et simultané de ces deux types de charge. Le réseau est construit en partitionnant les noeuds d'un graphe de De Bruijn et en assignant les partitions aux pairs. Les pairs équilibrent l'utilisation de la bande passante en repartitionnant les noeuds. On équilibre l'utilisation des ressources informatiques pour le stockage en dissociant l'emplacement d'un objet de celui de sa clé de recherche. L'article présente et analyse les protocoles requis pour main- tenir la structure de réseau et pour équilibrer la charge. Nous démontrons leur efficacité par simulation. Nous comparons également notre solution à d'autres approches., Load balancing is an important problem for structured peer-to-peer systems. We are particularly interested in the consumption of network bandwidth for routing traffic and in the usage of computer resources for object storage. In this paper, we investigate the possibility to simultaneously balance these two types of load. We present a structured peer-to-peer overlay that efficiently performs such simultaneous load balancing. The overlay is constructed by partitioning the nodes of a de Bruijn graph and by allocating the partitions to the peers. Peers balance network bandwidth consumption by repartitioning the nodes. Balancing of computer resources for storage is enabled by dissociating the actual storage location of an object from the location of its search key. The paper presents and analyzes the protocols required to maintain the overlay structure and perform load balancing. We demonstrate their efficiency by simulation. We also compare our proposed overlay network with other approaches.