Th. doct.-ing.--Électronique, électrotech., autom.--Toulouse 3, 1980. N°: 709.

Abstraction concepts based on process groups have largely dominated the design and implementation of communication patterns in message passing systems. Although such an approach seems pragmatic—given that participating processes form a ‘group’—in this dissertation, we discuss subtle issues that affect the qualitative and quantitative aspects of this approach. To address these issues, we introduce the concept of a ‘communication structure,’ which defines a communication pattern as an implicit runtime composition of localised patterns, known as ‘roles.’ During application development, communication structures are derived from the algorithm being implemented. These are then translated to an executable form by defining process specific data structures, known as ‘branching channels.’ The qualitative advantages of the communication structure approach are that the resulting programming model is non-ambiguous, uniform, expressive, and extensible. To use a pattern is to access the corresponding branching channels; to define a new pattern is simply to combine appropriate roles. The communication structure approach therefore allows immediate implementation of ad hoc patterns. Furthermore, it is guaranteed that every newly added role interfaces correctly with all of the existing roles, therefore scaling the benefit of every new addition. Quantitatively, branching channels improve performance by automatically overlapping computations and communications. The runtime system uses a receiver initiated communication protocol that allows senders to continue immediately without waiting for the receivers to respond. The advantage is that, unlike split-phase asynchronous communications, senders need not check whether the send operations were successful. Another property of branching channels is that they allow communications to be grouped, identified, and referenced. Communication structure specific parameters, such as message buffering, can therefore be specified immediately. Furthermore, a ‘commit’ based interface optimisation for send-and-forget type communications—where senders do not reuse sent data—is presented. This uses the referencing property of branching channels, allowing message buffering without incurring performance degradation due to intermediate memory copy.

Rapport de recherche bibliographique Diplôme d'études supérieures spécialisées : Ingénierie documentaire : Villeurbanne, ENSSIB : 2004. Rapport de recherche bibliographique Diplôme d'études supérieures spécialisées : Ingénierie documentaire : Lyon 1 : 2004.

Every organization goes through the same lifecycle. Through every step in the transformation to a better organization the communication structure changes. In this report there are examples of the communicational disadvantages that is connected to the communicational structure.By choosing to not have a formal communicational design, the manager takes a risk in spreading the information, the interaction, the control and the balance in creativity and constraint.This case organizations problem is that some parts of the organization has made more progress in the communicational structure than other parts. In this case the Collectivity structure has met the Formalized structure.Tha structural differences has came to affect the way of sharing information and it has become a situation where the information about the products is not stored in a safe way from a quality point of view. There is a gap between the two different ways of communicate.In this report I have created a model to identify problems in the communication structure. This is a tool to study the rest of the organization. This model is general and may be used on any organization. / En organisation genomgår olika livscykler. Genom varje steg i utvecklingen förändras organisationens kommunikationsstruktur. I den här rapporten finns exempel på de kommunikativa brister som uppkommit på grund av brister i den kommunikativa strukturen.Genom att inte ha en kommunikationsdesign för den formella kommunikationen utsätter ledningen organisationen för risker i informationsspridning, interaktion, kontroll och balans.Den studerade organisationen har kommit obalans genom att vissa avdelningar har kommit längre i sitt arbete med att formalisera och strukturera sitt arbete, medan andra avdelningar inte har haft samma strukturella utveckling. Interaktionen mellan dessa avdelningar har därför blivit en kommunikativ kulturkrock, där den Kollektiviserade strukturen möter den Formaliserade strukturen.De strukturella skillnaderna genomsyrar även avdelningarnas arbetssätt och innebär en brist ur kvalitetssynpunkt, då de båda strukturerna inte är överlappande.I rapporten har även en modell för att identifiera kommunikativa brister framtagits, för att caseföretaget ska kunna arbeta vidare med andra delar av organisationen och utreda sin kommunikativa struktur ytterligare. Modellen är av allmän karaktär och kan appliceras på en godtycklig organisation.

Real world systems like biological, social, technological, infrastructural and many others can be modeled as networks. The field of network science aims to study these complex networks and understand their structure and dynamics. A common feature of networks across domains is the distribution of the degree of the nodes according to a power-law (scale invariance). As a consequence of this skewness, the high degree nodes dominate the properties of these networks. The rich-club phenomenon is observed when the high degree or the rich nodes of the network prefer to connect amongst themselves. In the first part, the thesis investigates the rich-club phenomenon in higher order neighborhoods of the network by providing an elegant quantification using a geodesic distance based approach. This quantification helped in identifying networks where the trend and intensity of the rich-club phenomenon is significantly different in higher order neighborhoods compared to the immediate neighbors. The thesis also proposes a quantification of the importance of the non-rich nodes in the communication structure of the rich nodes, and broadly classify networks into core-periphery or cellular. Further a lack of universality is noticed in the structure of the networks belonging to a particular domain. It has been observed in the previous literature that the rich club connectivity dominates assortativity, a measure quantifying the mixing patterns in complex networks. Thus, assortativity is biased. To overcome such drawbacks, in the second part of the thesis proposes a novel measure called regularity. The analytical bounds on regularity and formulation of regularity for different network models are provided. Along with this a measure to quantify the mixing patterns of the neighborhood of a node called local regularity is also defined. The analysis on real-world network based on local regularity and degree distribution shows presence of both type of network, uniformly and non-uniformly mixed across different regions. Further normalized regularity is proposed to quantify the extent of preferential mixing in networks discounting the effect of degree distribution.