4,437 research outputs found

    Control theory for principled heap sizing

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    We propose a new, principled approach to adaptive heap sizing based on control theory. We review current state-of-the-art heap sizing mechanisms, as deployed in Jikes RVM and HotSpot. We then formulate heap sizing as a control problem, apply and tune a standard controller algorithm, and evaluate its performance on a set of well-known benchmarks. We find our controller adapts the heap size more responsively than existing mechanisms. This responsiveness allows tighter virtual machine memory footprints while preserving target application throughput, which is ideal for both embedded and utility computing domains. In short, we argue that formal, systematic approaches to memory management should be replacing ad-hoc heuristics as the discipline matures. Control-theoretic heap sizing is one such systematic approach

    Java for Cost Effective Embedded Real-Time Software

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    Learning, technologies, and time in the age of global neoliberal capitalism

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    Though diverse in nature, the articles in this collection discuss both socio-cultural and temporal transformations linked to technology and learning and can be classified into three broad themes. The first theme is interested in temporal experiences within time and learning; the second theme is about practical implementations of these concerns, and the third theme inquires into relationships between our understanding of time and human nature. In many articles, the boundaries between these themes are blurred and fluid. Yet, this general classification does indicate the present state of the art in studies of time, technology and education

    The pre-scientific concept of a "soul": A neurophenomenological hypothesis about its origin.

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    In this contribution I will argue that our traditional, folk-phenomenological concept of a "soul� may have its origins in accurate and truthful first-person reports about the experiential content of a specific neurophenomenological state-class. This class of phenomenal states is called the "Out-of-body experience� (OBE hereafter), and I will offer a detailed description in section 3 of this paper. The relevant type of conscious experience seems to possess a culturally invariant cluster of functional and phenomenal core properties: it is a specific kind of conscious experience, which can in principle be undergone by every human being. I propose that it probably is one of the most central semantic roots of our everyday, folk-phenomenological idea of what a soul actually is

    An integrative computational model for intestinal tissue renewal

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    Objectives\ud \ud The luminal surface of the gut is lined with a monolayer of epithelial cells that acts as a nutrient absorptive engine and protective barrier. To maintain its integrity and functionality, the epithelium is renewed every few days. Theoretical models are powerful tools that can be used to test hypotheses concerning the regulation of this renewal process, to investigate how its dysfunction can lead to loss of homeostasis and neoplasia, and to identify potential therapeutic interventions. Here we propose a new multiscale model for crypt dynamics that links phenomena occurring at the subcellular, cellular and tissue levels of organisation.\ud \ud Methods\ud \ud At the subcellular level, deterministic models characterise molecular networks, such as cell-cycle control and Wnt signalling. The output of these models determines the behaviour of each epithelial cell in response to intra-, inter- and extracellular cues. The modular nature of the model enables us to easily modify individual assumptions and analyse their effects on the system as a whole.\ud \ud Results\ud \ud We perform virtual microdissection and labelling-index experiments, evaluate the impact of various model extensions, obtain new insight into clonal expansion in the crypt, and compare our predictions with recent mitochondrial DNA mutation data. \ud \ud Conclusions\ud \ud We demonstrate that relaxing the assumption that stem-cell positions are fixed enables clonal expansion and niche succession to occur. We also predict that the presence of extracellular factors near the base of the crypt alone suffices to explain the observed spatial variation in nuclear beta-catenin levels along the crypt axis

    RELIGION AND ARTIFICIAL INTELLIGENCE

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    “What will be the relationship between religion and artificial intelligence?” This was the main research question for the current study. I chose Mikael Stenmark’s multidimensional model for describing relationship between religion and science, as my theoretical framework to help figure out the answer. Considering the novel and hypothetical nature of the topic it was necessary to accomplish following sub goals before I could tackle the main analysis: Establish the fact that religion is viable and growing part of the society in the future. Demonstrate how science and religion have been intertwined through the history until modern day. Confirm that the field of artificial intelligence is developing fast and intelligent machines will have growing presence in various areas of our lives. Give overview of relationship between religion and AI since the emergence of the field and examine this interconnection from different perspectives. Recent theories by Jose Casanova and Pippa Norris and correlating statistical data helped to establish and confirm that despite the popularity of the traditional secularization theory the number of people who affiliate themselves with religion is on the rise. Demonstration of the enduring interconnectedness of religion and science included covering birth of the modern science from the bosom of Christianity, followed by insight to problematic relationship between Islam and science. Thereafter I presented how new technologies are accepted in the religious environments of Islamic countries and Christian Africa. Additional examples demonstrated how religion has been related to the virtual worlds and explored how advances of innovative technology are creating potential alternatives for the traditional religion in the example of Transhumanism

    A Methodology for Transforming Java Applications Towards Real-Time Performance

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    The development of real-time systems has traditionally been based on low-level programming languages, such as C and C++, as these provide a fine-grained control of the applications temporal behavior. However, the usage of such programming languages suffers from increased complexity and high error rates compared to high-level languages such as Java. The Java programming language provides many benefits to software development such as automatic memory management and platform independence. However, Java is unable to provide any real-time guarantees, as the high-level benefits come at the cost of unpredictable temporal behavior.This thesis investigates the temporal characteristics of the Java language and analyses several possibilities for introducing real-time guarantees, including official language extensions and commercial runtime environments. Based on this analysis a new methodology is proposed for Transforming Java Applications towards Real-time Performance (TJARP). This method motivates a clear definition of timing requirements, followed by an analysis of the system through use of the formal modeling languageVDM-RT. Finally, the method provides a set of structured guidelines to facilitate the choice of strategy for obtaining real-time performance using Java. To further support this choice, an analysis is presented of available solutions, supported by a simple case study and a series of benchmarks.Furthermore, this thesis applies the TJARP method to a complex industrialcase study provided by a leading supplier of mission critical systems. Thecase study proves how the TJARP method is able to analyze an existing and complex system, and successfully introduce hard real-time guaranteesin critical sub-components

    Safe programming Languages for ABB Automation System 800xA

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    More than 90 % of all computers are embedded in different types of systems, for example mobile phones and industrial robots. Some of these systems are real-time systems; they have to produce their output within certain time constraints. They can also be safety critical; if something goes wrong, there is a risk that a great deal of damage is caused. Industrial Extended Automation System 800xA, developed by ABB, is a realtime control system intended for industrial use within a wide variety of applications where a certain focus on safety is required, for example power plants and oil platforms. The software is currently written in C and C++, languages that are not optimal from a safety point of view. In this master's thesis, it is investigated whether there are any plausible alternatives to using C/C++ for safety critical real-time systems. A number of requirements that programming languages used in this area have to fulfill are stated and it is evaluated if some candidate languages fulfill these requirements. The candidate languages, Java and Ada, are compared to C and C++. It is determined that the Java-to-C compiler LJRT (Lund Java-based Real Time) is a suitable alternative. The practical part of this thesis is concerned with the introduction of Java in 800xA. A module of the system is ported to Java and executed together with the original C/C++ solution. The functionality of the system is tested using a formal test suite and the performance and memory footprint of our solution is measured. The results show that it is possible to gradually introduce Java in 800xA using LJRT, which is the main contribution of this thesis
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