An abstract machine for Oz

Oz is a concurrent constraint language providing for first-class procedures, concurrent objects, and encapsulated search. DFKI Oz is an interactive implementation of Oz competitive in performance with commercial Prolog and Lisp systems. This paper describes AMOZ, the abstract machine underlying DFKI Oz. AMOZ implements rational tree constraints, first-class procedures, local computation spaces for deep guards, and preemptive and fair threads

Development of a System for 3D High-resolution Seismic Reflection Profiling on Lakes

A high-resolution three-dimensional (3D) seismic reflection system for small-scale targets in lacustrine settings has been developed. Its main characteristics include navigation and shot-triggering software that fires the seismic source at regular distance intervals (max. error of 0.25m) with real-time control on navigation using differential GPS (Global Positioning System). Receiver positions are accurately calculated (error<0.20m) with the aid of GPS antennas attached to the end of each of three 24-channel streamers. Two telescopic booms hold the streamers at a distance of 7.5m from each other. With a receiver spacing of 2.5m, the bin dimension is 1.25m in inline and 3.75m in crossline direction. To test the system, we conducted a 3D survey of about 1km2 in Lake Geneva, Switzerland, over a complex fault zone. A 5-m shot spacing resulted in a nominal fold of 6. A double-chamber bubble-cancelling 15/15in3 air gun (40-650Hz) operated at 80 bars and 1m depth gave a signal penetration of 300m below water bottom and a best vertical resolution of 1.1m. Processing followed a conventional scheme, but had to be adapted to the high sampling rates, and our unconventional navigation data needed conversion to industry standards. The high-quality data enabled us to construct maps of seismic horizons and fault surfaces in three dimensions. The system proves to be well adapted to investigate complex structures by providing non-aliased images of reflectors with dips up to 30

On the representation of temporal knowledge

The growing interest in an adequate modelling of time in Artificial Intelligence has given rise to the research discipline of Temporal Reasoning (TR). Due to different views, different approaches towards TR such as PL1, modal logics or Allen\u27s intervall logic have been investigated. It was realized at an early stage that each of this approaches has some strong points whereas it suffers from certain drawbacks. Thus recently, a number of research activities have emerged aiming at a combination of the classical paradigms for representing time. In the first part of this paper, we present an overview of the most important approaches to the integration of temporal knowledge into logic programming. In the second part, we present the CRONOLOG temporal logic programming language which has been developed to cover the quintessence of the approaches presented before. The third part of the paper describes TRAM, which it is an extension of CRONOLOG to a temporal knowledge representation system. Using TRAM it is possible to represent knowledge depending on time and to reason about this knowledge. TRAM has been conceptually based on a combination of modal logics with Allen\u27s interval logic. We present the Extended Modal Logics (EML) which establishes the theoretical framework for TRAM. We define an operational semantics and a horizontal compilation scheme for TRAM

Design, Implementierung und Evaluierung einer virtuellen Maschine für Oz

Diese Arbeit beschreibt Design, Implementierung und Evaluierung einer virtuellen Maschine für die Kernsprache von Oz, die wir mit L bezeichnen. Wir stellen L aus didaktischen Gründen als Erweiterung einer Teilsprache von SML dar. Die wichtigsten Unterschiede von L zu SML sind: logische Variablen, Threads, Synchronisation und dynamische Typisierung. Ausgehend von einer informellen Beschreibung der dynamischen Semantik über ein Graphenmodell entwickeln wir daraus schrittweise auf unterschiedlichen Abstraktionsebenen eine virtuelle Maschine für L. Wir beschreiben zunächst ein einfaches Grundmodell. Darauf aufbauend diskutieren wir verschiedene Optimierungen. Schließlich verfeinern wir weiter, indem wir auf Aspekte der Implementierung des Modells eingehen. Abschließend evaluieren wir die Effektivität der vorgestellten Techniken an einer Reihe von größeren Anwendungen aus der Praxis. Weiter zeigen wir, daß die Implementierung der Sprache kompetitiv ist mit den schnellsten Emulatoren für statisch getypte funktionale Sprachen.This thesis presents the design, implementation and evaluation of a virtual machine for the core language of Oz, which we call L. We present L for didactic reasons as an extension of a sublanguage of SML. The most important differences between L and SML are: logic variables, threads, synchronization and dynamic typing. Starting from an informal description of the dynamic semantics in terms of a graph model, we develop step by step on various levels of abstraction a virtual machine for L. We begin with a simple basic model. We then propose several optimizations of this model. Afterwards we keep refining our approach by addressing specific aspects of the implementation of the model. Finally we evaluate the effectiveness of the techniques using a set of larger real world applications. Further we show, that the implementation of the language is competitive with the fastest emulators for statically typed functional languages

Design, Implementierung und Evaluierung einer virtuellen Maschine für Oz

Diese Arbeit beschreibt Design, Implementierung und Evaluierung einer virtuellen Maschine für die Kernsprache von Oz, die wir mit L bezeichnen. Wir stellen L aus didaktischen Gründen als Erweiterung einer Teilsprache von SML dar. Die wichtigsten Unterschiede von L zu SML sind: logische Variablen, Threads, Synchronisation und dynamische Typisierung. Ausgehend von einer informellen Beschreibung der dynamischen Semantik über ein Graphenmodell entwickeln wir daraus schrittweise auf unterschiedlichen Abstraktionsebenen eine virtuelle Maschine für L. Wir beschreiben zunächst ein einfaches Grundmodell. Darauf aufbauend diskutieren wir verschiedene Optimierungen. Schließlich verfeinern wir weiter, indem wir auf Aspekte der Implementierung des Modells eingehen. Abschließend evaluieren wir die Effektivität der vorgestellten Techniken an einer Reihe von größeren Anwendungen aus der Praxis. Weiter zeigen wir, daß die Implementierung der Sprache kompetitiv ist mit den schnellsten Emulatoren für statisch getypte funktionale Sprachen.This thesis presents the design, implementation and evaluation of a virtual machine for the core language of Oz, which we call L. We present L for didactic reasons as an extension of a sublanguage of SML. The most important differences between L and SML are: logic variables, threads, synchronization and dynamic typing. Starting from an informal description of the dynamic semantics in terms of a graph model, we develop step by step on various levels of abstraction a virtual machine for L. We begin with a simple basic model. We then propose several optimizations of this model. Afterwards we keep refining our approach by addressing specific aspects of the implementation of the model. Finally we evaluate the effectiveness of the techniques using a set of larger real world applications. Further we show, that the implementation of the language is competitive with the fastest emulators for statically typed functional languages

A New Flexible and Economic Technology for the Low Pressure Sand Casting of Steel Alloys

Low pressure casting is a very well established process for the casting of aluminium alloys. In the field of ferrous materials, however, the process has so far only found a few applications. The crucial reasons for this are the low flexibility and poor economic efficiency of the existing technologies. Since 2016, a new technology has been developed at the Foundry Institute of the TU Bergakademie Freiberg, in which an induction crucible furnace can be used as a melting unit and, in combination with a cover including a casting pipe, as a casting unit. The new technology stands out from existing low-pressure casting technologies for ferrous materials, particularly in terms of its flexibility and cost-effectiveness. The main focus of the activities was the development of a casting pipe as well as the verification of its lifetime, the elaboration and verification of process parameters and sequences as well as the upscaling of the technology for an industrial application. In all considerations, the focus was on both the technical feasibility and the economic efficiency of the process. The result is extensive expertise that can be used in the future to offer a finished product for industrial applications as a plug-and-play solution together with an induction furnace construction company

A historiography of cultural heritage interpretation and policy in Kaesŏng, DPR Korea and their possible impact on inter-Korean rapprochement

Korea’s dividing ideologies of the past century, and the dominant efforts to legitimise the respective political agendas of the two States, have had an impact on the interpretation of, and the choice of focus within, cultural heritage and history. Cultural heritage policies are part of this particular historical narrative, reflected in heritage interpretations and activities. Whereas the socio-political studies of unification focus on a territorial unification, an approach coming from cultural heritage has the potential advantage of being able to focus on congruence through common roots, views of history and cultural values. Through an analysis of historical events and cultural heritage in the North Korean border town Kaesŏng, the research highlights the contribution of cultural heritage to past, present and future national perceptions. It also explores the impact that current socio-political developments have in turn on cultural heritage interpretations. Cultural heritage has not been, and will not to be, the major player in rapprochement politics practiced in South or North Korea. However, as a medium for collective memory and reflection, it can be a useful tool of rapprochement. Although heavily regulated by political agendas, recent joint Korean excavations in Kaesŏng, and one-day tourism tours for South Koreans to the site, provided an unique chance to observe the beginning of historical reflection on contested, compromised and shared cultural interpretations. For a time, the convergence of diverse and shared interpretations provided for the first steps towards mutual recognition and acknowledgement: that activities need to be continued