Predatory Exclusive Dealing

While the previous literature on exclusive dealing has been concerned with the question of how exclusive dealing can raise static profits, this paper analyzes the question of how exclusive dealing can be used to predate in a dynamic context. It is shown that exclusive dealing may arise even if it reduces static profits. Exclusivity provisions may not only allow excluding efficient competitors, but indeed are often a cheaper exclusionary tool than predatory pricing. This is the case if the prey's access to finance is not too limited. Furthermore, it is more likely that exclusive dealing is preferable compared to predatory pricing the more market power the predator has with respect to the prey

Predatory Exclusive Dealing

While the previous literature on exclusive dealing has been concerned with the question of how exclusive dealing can raise static profits, this paper analyzes the question of how exclusive dealing can be used to predate in a dynamic context. It is shown that exclusive dealing may arise even if it reduces static profits. Exclusivity provisions may not only allow excluding efficient competitors, but indeed are often a cheaper exclusionary tool than predatory pricing. This is the case if the prey's access to finance is not too limited. Furthermore, it is more likely that exclusive dealing is preferable compared to predatory pricing the more market power the predator has with respect to the prey.exclusive dealing; predation

Internet Governance: the State of Play

The Global Forum on Internet Governance held by the UNICT Task Force in New York on 25-26 March concluded that Internet governance issues were many and complex. The Secretary-General's Working Group on Internet Governance will have to map out and navigate this complex terrain as it makes recommendations to the World Summit on an Information Society in 2005. To assist in this process, the Forum recommended, in the words of the Deputy Secretary-General of the United Nations at the closing session, that a matrix be developed "of all issues of Internet governance addressed by multilateral institutions, including gaps and concerns, to assist the Secretary-General in moving forward the agenda on these issues." This paper takes up the Deputy Secretary-General's challenge. It is an analysis of the state of play in Internet governance in different forums, with a view to showing: (1) what issues are being addressed (2) by whom, (3) what are the types of consideration that these issues receive and (4) what issues are not adequately addressed

Analysis of HOM interaction between cavities by multi-modal s-parameter measurements

Accelerating cavities exchange HOM power through interconnecting beam pipes in case of signal frequencies above the cut-off of their propagating waveguide modes. This may lead either to improved HOM damping or - in the case most severe - to unwanted phase coherence of fields to the beam. Therefore the knowledge of the scattering properties of a cavity as a line element is needed to analyse all kinds of RF cavity-cavity interaction. Since there is a lack of measurement tools capable to provide a multidimensional scattering matrix at a given frequency point, we have been developing a method for this purpose. It uses a set of 2-port S-parameters of the device under test, embedded in a number of geometrically different RF environments. The application of the method is demonstrated with copper models of TESLA cavities

Transversal loss factor of an rf-focussing iris structure with rectangular holes

By replacing the irises in an electron linac by a slit one gets a structure capable of focussing/defocussing an electron beam (rf-quadrupoles). Therefore one can think of a combination of rf- and conventional magnetic quadrupoles for transversal focussing in linear-colliders. Furthermore they can meet the demands of BNS-damping without initial energy spread. Considering multibunch-operation of a collider, the long-range wake behaviour of this kind of structure has to be investigated. A three-cell structure has been built and investigated for dipole-type transversal long-range wakes. The experimental results are compared to numerical simulations done with MAFIA

Lateinisches und Romanisches in den Reichenauer Glossen

In today’s complex networks, timely identification and resolution of performance problems is extremely challenging. Current diagnostic practices to identify the root causes of such problems primarily rely on human intervention and investigation. Fully automated and scalable systems, which are capable of identifying complex problems are needed to provide rapid and accurate diagnosis. The study presented in this thesis creates the necessary scientific basis for the automatic diagnosis of network performance faults using novel intelligent inference techniques based on machine learning. We propose three new techniques for characterisation of network soft failures, and by using them, create the Intelligent Automated Network Diagnostic (IAND) system. First, we propose Transmission Control Protocol (TCP) trace characterisation techniques that use aggregated TCP statistics. Faulty network components embed unique artefacts in TCP packet streams by altering the normal protocol behaviour. Our technique captures such artefacts and generates a set of unique fault signatures. We first introduce Normalised Statistical Signatures (NSSs) with 460 features, a novel representation of network soft failures to provide the basis for diagnosis. Since not all 460 features contribute equally to the identification of a particular fault, we then introduce improved forms of NSSs called EigenNSS and FisherNSS with reduced complexity and greater class separability. Evaluations show that we can achieve dimensionality reduction of over 95% and detection accuracies up to 95% while achieving micro-second diagnosis times with these signatures. Second, given NSSs have features that are dependent on link properties, we introduce a technique called Link Adaptive Signature Estimation (LASE) using regression-based predictors to artificially generateNSSs for a large number of link parameter combinations. Using LASE, the system can be trained to suit the exact networking environment, however dynamic, with a minimal set of sample data. For extensive performance evaluation, we collected 1.2 million sample traces for 17 types of device failures on 8 TCP variants over various types of networks using a combination of fault injection and link emulation techniques. Third, to automate fault identification, we propose a modular inference technique that learns from the patterns embedded in the signatures, and create Fault Classifier Modules (FCMs). FCMs use support vector machines to uniquely identify individual faults and are designed using soft class boundaries to provide generalised fault detection capability. The use of a modular design and generic algorithm that can be trained and tuned based on the specific faults, offers scalability and is a key differentiator from the existing systems that use specific algorithms to detect each fault. Experimental evaluations show that FCMs can achieve detection accuracies of between 90% – 98%. The signatures and classifiers are used as the building blocks to create the IAND system with its two main sub-systems: IAND-k and IAND-h. The IANDk is a modular diagnostic system for automatic detection of previously known problems using FCMs. The IAND-k system is applied for accurately detecting faulty links and diagnosing problems in end-user devices in a wide range of network types (IAND-kUD, IAND-kCC). Extensive evaluation of the systems demonstrated high overall detection accuracies up to 96.6% with low false positives and over 90% accuracy even in the most difficult scenarios. Here, the FCMs use supervised machine learning methods and can only detect previously known problems. To extend the diagnostic capability to detect previously unknown problems, we propose IAND-h, a hybrid classifier system that uses a combination of unsupervised machine learning-based clustering and supervised machine learning-based classification. The evaluation of the system shows that previously unknown faults can be detected with over 92% accuracy. The IAND-h system also offers real-time detection capability with diagnosis times between 4 μs and 66 μs. The techniques and systems proposed during this research contribute to the state of the art of network diagnostics and focus on scalability, automation and modularity with evaluation results demonstrating a high degree of accuracy

Potzblitz Biologie – Ein Höhlenabenteuer nicht nur für Kinder : Didaktisch gut, spannend und unterhaltsam

Rezension zu: Heinrich Zankl, Mark Benecke, Hans-Wolfgang Helb, Dieter Sültemeyer (2007) Potzblitz Biologie. Die Höhlenabenteuer von Rita und Robert Erlebnis Wissenschaft, WILEY-VCH Verlag, Weinheim 2007, ISBN 3-527-31754-6, 264 Seiten, 24,90 Euro

Energy Propagation through the TESLA Channel: Measurements with Two Waveguides Modes

A new method for the determination of S-matrices of devices in multimoded waveguides and first experimental experiences are presented. The theoretical foundations are given. The scattering matrix of a TESLA copper cavity at a frequency above the cut-off of the second waveguide mode has been measured

The design of the HOM-damping cells for the S-band linear collider

Damping cells for the higher order modes are necessary for the S-band linear collider to minimize BBU (Beam-Break-Up). The construction of the damper cells has to take into account the different field geometries of the higher order modes. So two different types of dampers have been designed: a wall slotted an an iris slotted cell. In order to optimize the two types of damping cells with respect to damping strength, impedance matching between coupling system and waveguide dampers and between damping cell and undamped cells and the tuning system, damping cells of both types have been built and examinated