Dynamic Model of Signal Fading due to Swaying Vegetation (2009)
Michael Cheffena, Torbjörn Ekman
In this contribution, we use fading measurements at 2.45, 5.25, 29, and 60 GHz, and wind speed data, to study the dynamic effects of vegetation on propagating radiowaves. A new simulation model for...
.QL: Object-Oriented Queries Made Easy (2008)
Oege De Moor, Damien Sereni, Mathieu Verbaere, Elnar Hajiyev, Pavel Avgustinov, Torbjörn Ekman, ...
Abstract. These notes are an introduction to.QL, an object-oriented query language for any type of structured data. We illustrate the use of.QL in assessing software quality, namely to find bugs, to...
Nordic Journal of Computing IMPLEMENTING JAVA COMPILERS USING ReRAGs (2008)
Anders Nilsson, Anders Ive, Torbjörn Ekman, Görel Hedin
Abstract. Rewritable Reference Attributed Grammars (ReRAGs) is a recently developed compiler-compiler technology based on object-orientation, aspect-orientation, reference attributed grammars, and...
Real Java for Real Time- Gain and Pain (2008)
Anders Nilsson, Torbjörn Ekman, Klas Nilsson
The Java programming language, being a portable and safe object-oriented language, has gained much interest among embedded and real-time systems developers. However, standard Java implementations...
A case study of separation of concerns in compiler construction
Automatic renovation of Java programs using ReRAGs — examples and ideas (2008)
Abstract. When new constructs are added to a language there is a need for renovating existing programs to make use of the new constructs. We discuss how this can be done using object-oriented ReRAGs...
Flexible Language Interoperability (2008)
Torbjörn Ekman, Peter Mechlenborg, Mu Aps, Ulrik Pagh Schultz
Virtual machines raise the abstraction level of the execution environment at the cost of restricting the set of supported languages. Moreover, the ability of a language implementation to integrate...
Keynote Address:.QL for Source Code Analysis Oege de Moor, Mathieu Verbaere, Elnar Hajiyev, (2008)
Pavel Avgustinov, Torbjörn Ekman, Neil Ongkingco, Damien Sereni, Julian Tibble
Many tasks in source code analysis can be viewed as evaluating queries over a relational representation of the code. Here we present an object-oriented query language, named.QL, and demonstrate its...
On The Efficient Implementation Of The Capon Spectral Estimator (2007)
Torbjörn Ekman, Torbj Orn Ekman, Andreas Jakobsson, Petre Stoica
We present an efficient implementation of the Amplitude Spectrum Capon (ASC) estimator. The implementation is based on the FFT and an efficient computation of the Cholesky-factor for the inverse...
Identifying Collisions in NTSB Accident Summary Reports (2007)
Torbjörn Ekman, Anders Nilsson
Insurance companies are often faced with the task of analyzing car accident reports in order to try to find out how the accident took place, and who to blame for it. The analysis could in many cases...
New Approaches for Channel Prediction Based on Sinusoidal Modeling (2007)
Ming Chen, Torbjörn Ekman, Mats Viberg
Long-range channel prediction is considered to be one of the most important enabling technologies to future wireless communication systems. The prediction of Rayleigh fading channels is studied in...
Extensible Compiler Construction (2006)
Processing of programs is a core area in computer science. A compiler that translates source text to machine language is the most well-known kind of tool in this area, but there are numerous other...
Extensible Compiler Construction (2006)
Torbjörn Ekman, Typeset Using Latexε
Processing of programs is a core area in computer science. A compiler that translates source text to machine language is the most well-known kind of tool in this area, but there are numerous other...
Modular name analysis for Java using JastAdd (2005)
Abstract. Name analysis for Java is challenging with its complex visibility rules involving nested scopes, inheritance, qualified access, and syntactic ambiguities. We show how Java name analysis...
This thesis presents an object-oriented technique for rewriting abstract syntax trees in order to simplify compilation. The technique, Rewritable Reference Attributed Grammars (ReRAGs), is completely...
Adaptive modulation systems for predicted wireless channels (2004)
Sorour Falahati, Arne Svensson, Mikael Sternad, Torbjörn Ekman
Abstract — When adaptive modulation is used to counter short-term fading in mobile radio channels, signaling delays create problems with outdated channel state information. The use of channel power...
Welcome to the 11th Nordic Workshop on Programming and Software Development (2004)
Welcome To The, Ivan Porres, Johan Lilius, Luka Milovanov, Kurt Nørmark, Thomas Vestdam, ...
The higher the number of clock cycles per main memory access becomes, the more important it will be to use caches to their full potential. We present a method for finding good points at which to...
Adaptive modulation systems for predicted wireless channels (2004)
Sorour Falahati, Arne Svensson, Mikael Sternad, Torbjörn Ekman
Abstract — When adaptive modulation is used to counter short-term fading in mobile radio channels, signaling delays create problems with outdated channel state information. The use of channel power...
Prediction of Mobile Radio Channels : Modeling and Design (2002)
Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation and fast link adaptation. This thesis deals with...
Prediction of Mobile Radio Channels : Modeling and Design (2002)
Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation and fast link adaptation. This thesis deals with...
Garbage Collector Interface (2002)
Ive, Anders, Blomdell, Anders, Ekman, Torbjörn, Henriksson, Roger, Nilsson, Anders, Nilsson, Klas, ...
The purpose of the presented garbage collector interface is to provide a universal interface for many different implementations of garbage collectors. This is to simplify the integration and exchange...
Power prediction on Broadband Channels (2002)
Abstract — Prediction of the rapidly fading envelope of a mobile radio channel enables a number of capacity improving techniques like fast resource allocation or fast adaptive modulation. Some...
Prediction of Mobile Radio Channels - Modeling and Design (2002)
Ekman, T., 2002. Prediction of Mobile Radio Channels: Modeling and Design, 254 pp. Uppsala. ISBN 91-506-1625-0.
Deterministic Java in tiny embedded systems (2001)
Nilsson, Anders, Ekman, Torbjörn
As embedded systems become more and more complex, and the time to market becomes shorter, there is a need in the embedded systems community to find better programming languages that let the...
Nonlinear Prediction Of Mobile Radio Channels: Measurements And Mars Model Designs (1999)
The rapid time variation of mobile radio channels is often modeled as a random process with second order moments reflecting vehicle speed, bandwidth and the scattering environment. These statistics...
Capon And Apes Spectrum Estimation For Real-Valued Signals (1998)
Andreas Jakobsson, Torbjörn Ekman, Torbj Orn Ekman, Petre Stoica
This paper considers the problem of estimating the spectrum of real-valued signals. We propose real-valued versions of the Capon and the APES spectral estimators. The estimators are derived as...
On Efficient Implementation Of The Capon Algorithm
Torbjörn Ekman, Andreas Jakobsson, Petre Stoica
We present an efficient implementation of the Amplitude Spectrum Capon (ASC) estimator, denoted the B-ASC estimator. The implementation, which is based on the Burg algorithm and the Fast Fourier...