OASIcs: OpenAccess Series in Informatics

http://drops.dagstuhl.de/opus/institut_oasics.php

List of Papers (Total 41)

Explaining Actual Causation via Reasoning About Actions and Change

In causality, an actual cause is often defined as an event responsible for bringing about a given outcome in a scenario. In practice, however, identifying this event alone is not always sufficient to provide a satisfactory explanation of how the outcome came to be. In this paper, we motivate this claim using well-known examples and present a novel framework for reasoning more...

Fine-Grain Iterative Compilation for WCET Estimation

Compiler optimizations, although reducing the execution times of programs, raise issues in static WCET estimation techniques and tools. Flow facts, such as loop bounds, may not be automatically found by static WCET analysis tools after aggressive code optimizations. In this paper, we explore the use of iterative compilation (WCET-directed program optimization to explore the...

How to Measure the Robustness of Shunting Plans

The general problem of scheduling activities subject to temporal and resource constraints as well as a deadline emerges naturally in numerous application domains such as project management, production planning, and public transport. The schedules often have to be implemented in an uncertain environment, where disturbances cause deviations in the duration, release date or deadline...

Learning Effect Axioms via Probabilistic Logic Programming

In this paper we showed how we can automatically learn the structure and parameters of probabilistic effect axioms for the Simple Event Calculus (SEC) from positive and negative example interpretations stated as short dialogue sequences in natural language. We used the cplint framework for this task that provides libraries for structure and parameter learning and for answering...

Demand for Medical Care by the Elderly: A Nonparametric Variational Bayesian MixtureApproach

Outpatient care is a large share of total health care spending, making analysis of data on outpatient utilization an important part of understanding patterns and drivers of health care spending growth. Common features of outpatient utilization measures include zero-inflation, over-dispersion, and skewness, all of which complicate statistical modeling. Mixture modeling is a...

Improving the Latency and Throughput of ZooKeeper Atomic Broadcast

ZooKeeper is a crash-tolerant system that offers fundamental services to Internet-scale applications, thereby reducing the development and hosting of the latter. It consists of >3 servers that form a replicated state machine. Maintaining these replicas in a mutually consistent state requires executing an Atomic Broadcast Protocol, Zab, so that concurrent requests for state...

An Improved Algorithm for the Periodic Timetabling Problem

We consider the computation of periodic timetables, which is a key task in the service design process of public transportation companies. We propose a new approach for solving the periodic timetable optimisation problem. It consists of a (partially) heuristic network aggregation to reduce the problem size and make it accessible to standard mixed-integer programming (MIP) solvers...

Analysis of Strengths and Weaknesses of a MILP Model for Revising Railway Traffic Timetables

A railway timetable is typically planned one year in advance, but may be revised several times prior to the time of operation in order to accommodate on-demand slot requests for inserting additional trains and network maintenance. Revising timetables is a computationally demanding task, given the many dependencies and details to consider. In this paper, we focus on the potential...

Comparing Extant Story Classifiers: Results & New Directions

Having access to a large set of stories is a necessary first step for robust and wide-ranging computational narrative modeling; happily, language data - including stories - are increasingly available in electronic form. Unhappily, the process of automatically separating stories from other forms of written discourse is not straightforward, and has resulted in a data collection...

Scheduling Autonomous Vehicle Platoons Through an Unregulated Intersection

We study various versions of the problem of scheduling platoons of autonomous vehicles through an unregulated intersection, where an algorithm must schedule which platoons should wait so that others can go through, so as to minimize the maximum delay for any vehicle. We provide polynomial-time algorithms for constructing such schedules for a k-way merge intersection, for constant...

Sensitivity Analysis and Coupled Decisions in Passenger Flow-Based Train Dispatching

Frequent train delays make passenger-oriented train dispatching a task of high practical relevance. In case of delays, dispatchers have to decide whether trains should wait for one or several delayed feeder trains or should depart on time. To support dispatchers, we have recently introduced the train dispatching framework PANDA (CASPT 2015). In this paper, we present and evaluate...

Profile Detection Through Source Code Static Analysis

The present article reflects the progress of an ongoing master's dissertation on language engineering. The main goal of the work here described, is to infer a programmer's profile through the analysis of his source code. After such analysis the programmer shall be placed on a scale that characterizes him on his language abilities. There are several potential applications for such...

Computing Argumentation with Matrices

Abstract argumentation frameworks with finitely many arguments can be presented in matrix form. For this reason, the strengths and weaknesses of matrix operations are migrated from a mathematical representation to a computer science interpretation. We present matrix operation algorithms that can answer whether a given set of arguments is part of an argumentation extension.

Tell Me a Story: Toward More Expressive and Coherent Computational Narratives (Invited Talk)

Since narrative is a foundational framework for the on-going co-evolution of human cognition and culture, the advent of computation as a new medium for representing narratives offers the promise of ratcheting up human understanding and expressive power, just as previous media of representation like language and writing have done. But digital representation often produces...

Everything you know is wrong: The amazing time traveling CPU, and other horrors of concurrency

In this paper, we shall explore weak memory models, their insidious effects, and how it could happen to you! It shall explained how and why both compilers and CPUs rewrite your program to make it faster, the inevitable fallout of this, and what you can do to protect your code. We shall craft a lock, building from a na�ve and broken implementation up to a safe and correct form...

Gathering Background Knowledge for Story Understanding through Crowdsourcing

Successfully comprehending stories involves integration of the story information with the reader's own background knowledge. A prerequisite, then, of building automated story understanding systems is the availability of such background knowledge. We take the approach that knowledge appropriate for story understanding can be gathered by sourcing the task to the crowd. Our...

A Task Based model for R\'ecit Generation from Sensor Data: An Early Experiment

Automatic story generation is the subject of a growing research effort. However, in this domain, stories are generally produced from fictional data. In this paper, we present a task model used for automatic story generation from real data focusing on the narrative planning. The aim is to generate r�cits (stories) from sensors data acquired during a ski sortie. The model and some...

JSON on Mobile: is there an Efficient Parserl

The two largest causes for battery consumption on mobile devices are related with the display and network operations. Since most application need to share data and communicate with remote servers, communications should be as lightweight and efficient as possible. In network communication, serialization plays a central role as the process of converting an object into a stream of...

Rocchio's Model Based on Vector Space Basis Change for Pseudo Relevance Feedback

Rocchio's relevance feedback model is a classic query expansion method and it has been shown to be effective in boosting information retrieval performance. The main problem with this method is that the relevant and the irrelevant documents overlap in the vector space because they often share same terms (at least the terms of the query). With respect to the initial vector space...

An Overview of Open Information Extraction (Invited talk)

Open Information Extraction (OIE) is a recent unsupervised strategy to extract great amounts of basic propositions (verb-based triples) from massive text corpora which scales to Web-size document collections. We will introduce the main properties of this extraction method.

Evaluation of Social Personalized Adaptive E-Learning Environments: End-User Point of View

The use of adaptations, along with the social affordances of collaboration and networking, carries a great potential for improving e-learning experiences. However, the review of the previous work indicates current e-learning systems have only marginally explored the integration of social features and adaptation techniques. The overall aim of this research, therefore, is to...

Evolution and Evaluation of the Penalty Method for Alternative Graphs

Computing meaningful alternative routes in a road network is a complex problem -- already giving a clear definition of a best alternative seems to be impossible. Still, multiple methods describe how to compute reasonable alternative routes, each according to their own quality criteria. Among these methods, the penalty method has received much less attention than the via-node or...

Using Unexpected Simplicity to Control Moral Judgments and Interest in Narratives

The challenge of narrative automatic generation is to produce not only coherent, but interesting stories. This study considers the problem within the Simplicity Theory framework. According to this theory, interesting situations must be unexpectedly simple, either because they should have required complex circumstances to be produced, or because they are abnormally simple, as in...

Combining Language Independent Part-of-Speech Tagging Tools

Part-of-speech tagging is a fundamental task of natural language processing. For languages with a very rich agglutinating morphology, generic PoS tagging algorithms do not yield very high accuracy due to data sparseness issues. Though integrating a morphological analyzer can efficiently solve this problem, this is a resource-intensive solution. In this paper we show a method of...

A General Introduction To Graph Visualization Techniques

Generally, a graph is an abstract data type used to represent relations among a given set of data entities. Graphs are used in numerous applications within the field of information visualization, such as VLSI (circuit schematics), state-transition diagrams, and social networks. The size and complexity of graphs easily reach dimensions at which the task of exploring and navigating...