Performance investigation of a document retrieval system on a voice-data integrated token ring local area network

Lately, the interest in integration of voice and data on local computer networks has been on the rise. Subsequently, much research has been devoted to exploring various techniques that are implementable using the existing standards. This research has focused on the design issues in implementing a document retrieval system on a token ring network. The presence of voice and data traffic on the network complicates the protocol design further. The performance requirements of these traffic types are different. Voice creates stream traffic on a network, where as data traffic is bursty. Voice packets need to be delivered within a limited time interval, whereas the data emphasizes on error-free delivery. The necessity and the technological feasibility with off-the-shelf components has prompted this study. A possible solution is discussed in this dissertation;During the course of this research, due to the time consuming nature of simulation experiments, a need for efficient simulation techniques was felt. Thus, as a byproduct of the initial goal of protocol design, an approximate version of the regenerative simulation was developed and is discussed here in detail;Lastly, modeling difficulties encountered in forming an analytical model are listed and a performance analysis of the subsystems of interest is given

New experimentalism applied to evolutionary computation

This thesis develops a solid statistical methodology to analyze search heuristics such as evolutionary algorithm s based on the concept of the new experimentalism. The new experimentalism is an influential discipline in the modern philosophy of science. The new experimentalists are seeking for a relatively secure basis for science, not in theory or observation, but in experiment. Deborah Mayo - one of its prominent proponents - developed a detailed way in which sc ientific claims can be validated by experiment. First, the concept of the new experimentalism for computer experiments is introduced. The difference between significant and meani ngful results is detailed. Following Mayo, a re-interpretation of the Neyman-Pearson theory of testing for computer experiments is given. Since statistical tests can be used as l earning tools, they provide means to extend widely accepted popperian paradigms. Models are characterized as central elements of science. We claim that experiment dominates theor y. Many, even conflicting, theories can co-exist independently for one unique experimental result. Maybe there is no theory applying to every phenomenon, but many simple theories describing what happens from case to case. Basic definitions from computational statistics, classical design of experiments (DOE), and modern design of computer experiments (DAC E) are explained to provide the reader with the required background information from statistics. An elevator group control model, which has been developed in cooperation with one of the world's leading elevator manufacturers, is introduced as an example for complex real-world optimization problems. It is used to illustrate the difference between art ificial functions from test suites and real-world problems. Problems related to these commonly used test-suites are discussed. Experimenters have to decide where to place sample points. Classical and modern experimental designs are compared to describe the difference between space-filling designs and designs that place experimental points at the boundari es of the experimental region. In many situations, it might be beneficial to generate the design points not at once, but sequentially. A sequential design, which provides a basis for a parameter tuning method, is developed. Exogenous strategy parameters, which have to be specified before an optimization algorithm can be started, are presented for determi nistic and stochastic search algorithms. The discussion of the concept of optimization provides the foundation to define performance measures for search heuristics. Optimization relies on a number of very restrictive assumptions that are not met in many real-world settings. Efficiency and effectivity are introduced with respect to these problems as two i mportant categories to classify performance measures. As the pre-requisites have been introduced, experiments can be performed and analyzed in framework of the new experimentalis m. A classical approach, based on DOE, is presented first. Then, sequential parameter optimization (SPO) is developed as a modern methodology to improve ('tune') and co mpare the performance of algorithms. It is demonstrated how the tuning process, which requires only a relatively small number of experiments, can improve the algorithm's per formance significantly. Even more, the new experimentalism, as introduced and applied in this thesis, provides means to understand the algorithm's performance. Various schem es for selection under noise are introduced to demonstrate this feature. To give an example, it is demonstrated how threshold selection can improve the local and global performan ce of search heuristics under noise. Threshold selection can be characterized as a smart and simple heuristic that performs relatively good in certain environments. These heurist ics are interpreted in Herbert Simon's framework of bounded rationality. Finally, a commonly accepted model that describes the relation between experiment and theory is rev ised and enhanced

Informationsverarbeitung im Informationsmanagement : Modellierung von Aufgaben und verarbeiteten Informationen am Beispiel der Information Technology Infrastructure Library (ITIL)

Das Informationsmanagement im Gesundheitswesen entwickelt Informationssysteme von Krankenhäusern und medizinischen Organisationen weiter. Dazu benötigt es Informationen, die ihm von Informationsmanagement-Informationssystem (IMIS) bereitgestellt werden. Das IMIS muss ebenfalls zielgerichtet weiterentwickelt werden. Die Grundlage für die Bewertung und Konstruktion eines IMIS ist ein Modell der Aufgaben und verarbeiteten Informationen im Informationsmanagement. Der Autor entwickelt eine Formalisierung der Informationsverarbeitung und darauf aufbauend Kriterien für Modelle der Informationsverarbeitung im Informationsmanagement im Gesundheitswesen sowie Modellierungsregeln und ein Vorgehen zur Modellierung. Die Angemessenheit der entwickelten Formalisierung und der Kriterien, der Regeln und des Vorgehens zeigt der Autor mit der Modellierung der Informationsverarbeitung in den neun Kernprozessen der Information Technology Infrastructure Library (ITIL), einer Sammlung von Empfehlungen für das Management von IT-Dienstleistungen. Aufbauend auf einer erweiterten Version dieses Modells kann ein IMIS für das Gesundheitswesen konstruiert werden

The Extraction and Usage of Patterns from Video Data to Support Multi-Agent Based Simulation

The research work presented in this thesis is directed at addressing the knowledge acquisition bottleneck frequently encountered in computer simulation. The central idea is to extract the required knowledge from video data and use this to drive a computer simulation instead of the more conventional approach of interviewing domain experts and somehow encapsulating this knowledge in a manner whereby it can be used in the context of computer simulation. More specifically the idea presented in this thesis is to extract object location information from video data and then to mine this information to identify Movement Patterns (MPs) and then to utalise these MPs in the context of computer simulation. To act as a focus for the work rodent behaviour simulation was considered. Partly because video data concerning rodent behaviour was relatively easy to obtain and partly because there is a genuine need to achieve a better understanding of rodent behaviour. This is especially the case in the context of crop damage. There are a variety of computer simulation frameworks. One that naturally lends itself to rodent simulation is Multi Agent Based Simulation (MABS) whereby the objects to be simulated (rodents) are encapsulated in terms of software agents. In more detail the work presented is directed at a number of research issues in the context of the above: (i) mechanisms to identify a moving object in video data and extracting associated location information, (ii) the mining of MPs from the extracted location information, (iii) the representation of MPs in such a way that they are compatible with computer simulation frameworks especially MABS frameworks and (iv) mechanisms where by MPs can be utilized and interacted with so as to drive a MABS. Overall two types of mechanisms are considered, Absolute and Relative. The operation of rodent MABSs, driven using the proposed MP concept, is fully illustrated in the context of different categories of scenarios. The evaluation of the proposed MP driven MABSs was conducted by comparing real world scenarios to parallel simulated scenarios. The results presented in the thesis demonstrated that the proposed mechanisms for extracting locations, and consequently mining MPs, from video data to drive a MABS provides a useful approach to effective computer simulation that will have wide ranging benefits