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Jakub Kowalski

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School of the Art Institute of Chicago

Yale University

University of Ulster

Duke University

Kansas State University

Lydia Papadimitriou

Liverpool John Moores University

Ann-Sophie Lehmann

University of Groningen

Christiane Gruber

University of Michigan

University of St Andrews

Saint-Petersburg Stieglitz State Academy of Art and Design

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Papers by Jakub Kowalski

Game Description Language Compiler Construction

Lecture Notes in Computer Science, 2013

We describe a multilevel algorithm compiling a general game description in GDL into an optimized ... more We describe a multilevel algorithm compiling a general game description in GDL into an optimized reasoner in a low level language. The aim of the reasoner is to efficiently compute game states and perform simulations of the game. This is essential for many General Game Playing systems, especially if they use simulation-based approaches. Our compiler produces a faster reasoner than similar approaches used so far. The compiler is implemented as a part of the player Dumalion. Although we concentrate on compiling GDL, the developed methods can be applied to similar Prolog-like languages in order to speed up computations.

A Fast Algorithm Finding the Shortest Reset Words

Lecture Notes in Computer Science, 2013

Computing the shortest reset words of synchronizing automata

Journal of Combinatorial Optimization, 2013

In this paper we give the details of our new algorithm for finding minimal reset words of finite ... more In this paper we give the details of our new algorithm for finding minimal reset words of finite synchronizing automata. The problem is known to be computationally hard, so our algorithm is exponential in the worst case, but it is faster than the algorithms used so far and it performs well on average. The main idea is to use a bidirectional breadth-first-search and radix (Patricia) tries to store and compare subsets. A good performance is due to a number of heuristics we apply and describe here in a suitable detail. We give both theoretical and practical arguments showing that the effective branching factor is considerably reduced. As a practical test we perform an experimental study of the length of the shortest reset word for random automata with up to n = 350 states and up to k = 10 input letters. In particular, we obtain a new estimation of the expected length of the shortest reset word ≈ 2.5 √ n − 5 for binary automata and show that the error of this estimate is sufficiently small. Experiments for automata with more than two input letters show certain trends with the same general pattern.

New Limits on the UltraHigh Energy Cosmic Neutrino Flux from the ANITA Experiment

Physical Review Letters, 2011

We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA... more We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of E ν ≃ 3 × 10 18 eV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultra-high energy extensive air showers.

Observation of Ultrahigh-Energy Cosmic Rays with the ANITA Balloon-Borne Radio Interferometer

Physical Review Letters, 2010

We report the observation of 16 cosmic ray events with a mean energy of 1.5×1019eV via radio puls... more We report the observation of 16 cosmic ray events with a mean energy of 1.5×1019eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2° for the event arrival directions.

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for UHE neutrino astronomy

Astroparticle Physics, 2007

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an un... more Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of radioglaciological measurements performed approximately 10 km north of Taylor Dome Station, Antarctica from Dec. 6, 2006 - Dec. 16, 2006. Using RF signals broadcast from: a) an englacial discone, submerged to a depth of 100 meters and broadcasting to a surface dual polarization horn receiver, and b) a dual-polarization horn antenna on the surface transmitting signals which reflect off the underlying bed and back up to the surface receiver, we have made time-domain estimates of both the real (index-of-refraction) and imaginary (attenuation length) components of the complex ice dielectric constant. We have also measured the uniformity of ice response along two orthogonal axes in the horizontal plane. We observe a wavespeed asymmetry of order 0.1%, projected onto the vertical propagation axis, consistent with some previous measurements, but somewhat lower than others.

The Antarctic Impulsive Transient Antenna ultra-high energy neutrino detector: Design, performance, and sensitivity for the 2006–2007 balloon flight

Astroparticle Physics, 2009

We present a comprehensive report on the experimental details of the Antarctic Impulsive Transien... more We present a comprehensive report on the experimental details of the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, including the design philosophy and realization, physics simulations, performance of the instrument during its first Antarctic flight completed in January of 2007, and expectations for the limiting neutrino detection sensitivity.

PRELIMINARY RESULT FROM ANITA EXPERIMENT

Modern Physics Letters A, 2008

The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a balloon-borne neutrino telescop... more The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a balloon-borne neutrino telescope which consists of an array of 32 broad-band horn antennas. It successfully completed a 35 day flight over Antarctica during the 2006-2007 austral summer. The primary goal of ANITA is to search for astrophysical neutrinos with energies E > 10 19 eV by detecting radio Cherenkov signals from neutrino induced showers in the Antarctic ice. We present preliminary results from ongoing analyses of ANITA data.

Results from the ANITA experiment (Analysis A)

Journal of Physics: Conference Series, 2008

New Limits on the Ultrahigh Energy Cosmic Neutrino Flux from the ANITA Experiment

Physical Review Letters, 2009

We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA... more We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of 3 EeV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultra-high energy extensive air showers.

Observations of the Askaryan Effect in Ice

Physical Review Letters, 2007

We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Chere... more We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations.

Observation of ultra-high-energy cosmic rays with the ANITA balloon-borne radio interferometer

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2010

We report the observation of sixteen cosmic ray events of mean energy of 1.5 × 10 19 eV, via radi... more We report the observation of sixteen cosmic ray events of mean energy of 1.5 × 10 19 eV, via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present the first ultra-wideband, far-field measurements of the radio spectral density of geosynchrotron emission in the range from 300-1000 MHz. The emission is 100% linearly polarized in the plane perpendicular to the projected geomagnetic field. Fourteen of our observed events are seen to have a phase-inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon.

Observations of microwave continuum emission from air shower plasmas

Physical Review D, 2008

We investigate a possible new technique for microwave detection of cosmic ray extensive air showe... more We investigate a possible new technique for microwave detection of cosmic ray extensive air showers which relies on detection of expected continuum radiation in the microwave range, caused by free-electron collisions with neutrals in the tenuous plasma left after the passage of the shower. We performed an initial experiment at the AWA (Argonne Wakefield Accelerator) laboratory in 2003 and measured broadband microwave emission from air ionized via high energy electrons and photons. A follow-up experiment at SLAC (Stanford Linear Accelerator Center) in summer of 2004 confirmed the major features of the previous AWA observations with better precision. Prompted by these results we built a prototype detector using satellite television technology, and have made measurements suggestive of detection of cosmic ray extensive air showers. The method, if confirmed by experiments now in progress, could provide a high-duty cycle complement to current nitrogen fluorescence observations.

Game Description Language Compiler Construction

Lecture Notes in Computer Science, 2013

We describe a multilevel algorithm compiling a general game description in GDL into an optimized ... more We describe a multilevel algorithm compiling a general game description in GDL into an optimized reasoner in a low level language. The aim of the reasoner is to efficiently compute game states and perform simulations of the game. This is essential for many General Game Playing systems, especially if they use simulation-based approaches. Our compiler produces a faster reasoner than similar approaches used so far. The compiler is implemented as a part of the player Dumalion. Although we concentrate on compiling GDL, the developed methods can be applied to similar Prolog-like languages in order to speed up computations.

A Fast Algorithm Finding the Shortest Reset Words

Lecture Notes in Computer Science, 2013

Computing the shortest reset words of synchronizing automata

Journal of Combinatorial Optimization, 2013

In this paper we give the details of our new algorithm for finding minimal reset words of finite ... more In this paper we give the details of our new algorithm for finding minimal reset words of finite synchronizing automata. The problem is known to be computationally hard, so our algorithm is exponential in the worst case, but it is faster than the algorithms used so far and it performs well on average. The main idea is to use a bidirectional breadth-first-search and radix (Patricia) tries to store and compare subsets. A good performance is due to a number of heuristics we apply and describe here in a suitable detail. We give both theoretical and practical arguments showing that the effective branching factor is considerably reduced. As a practical test we perform an experimental study of the length of the shortest reset word for random automata with up to n = 350 states and up to k = 10 input letters. In particular, we obtain a new estimation of the expected length of the shortest reset word ≈ 2.5 √ n − 5 for binary automata and show that the error of this estimate is sufficiently small. Experiments for automata with more than two input letters show certain trends with the same general pattern.

New Limits on the UltraHigh Energy Cosmic Neutrino Flux from the ANITA Experiment

Physical Review Letters, 2011

We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA... more We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of E ν ≃ 3 × 10 18 eV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultra-high energy extensive air showers.

Observation of Ultrahigh-Energy Cosmic Rays with the ANITA Balloon-Borne Radio Interferometer

Physical Review Letters, 2010

We report the observation of 16 cosmic ray events with a mean energy of 1.5×1019eV via radio puls... more We report the observation of 16 cosmic ray events with a mean energy of 1.5×1019eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2° for the event arrival directions.

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for UHE neutrino astronomy

Astroparticle Physics, 2007

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an un... more Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of radioglaciological measurements performed approximately 10 km north of Taylor Dome Station, Antarctica from Dec. 6, 2006 - Dec. 16, 2006. Using RF signals broadcast from: a) an englacial discone, submerged to a depth of 100 meters and broadcasting to a surface dual polarization horn receiver, and b) a dual-polarization horn antenna on the surface transmitting signals which reflect off the underlying bed and back up to the surface receiver, we have made time-domain estimates of both the real (index-of-refraction) and imaginary (attenuation length) components of the complex ice dielectric constant. We have also measured the uniformity of ice response along two orthogonal axes in the horizontal plane. We observe a wavespeed asymmetry of order 0.1%, projected onto the vertical propagation axis, consistent with some previous measurements, but somewhat lower than others.

The Antarctic Impulsive Transient Antenna ultra-high energy neutrino detector: Design, performance, and sensitivity for the 2006–2007 balloon flight

Astroparticle Physics, 2009

We present a comprehensive report on the experimental details of the Antarctic Impulsive Transien... more We present a comprehensive report on the experimental details of the Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon payload, including the design philosophy and realization, physics simulations, performance of the instrument during its first Antarctic flight completed in January of 2007, and expectations for the limiting neutrino detection sensitivity.

PRELIMINARY RESULT FROM ANITA EXPERIMENT

Modern Physics Letters A, 2008

The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a balloon-borne neutrino telescop... more The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a balloon-borne neutrino telescope which consists of an array of 32 broad-band horn antennas. It successfully completed a 35 day flight over Antarctica during the 2006-2007 austral summer. The primary goal of ANITA is to search for astrophysical neutrinos with energies E > 10 19 eV by detecting radio Cherenkov signals from neutrino induced showers in the Antarctic ice. We present preliminary results from ongoing analyses of ANITA data.

Results from the ANITA experiment (Analysis A)

Journal of Physics: Conference Series, 2008

New Limits on the Ultrahigh Energy Cosmic Neutrino Flux from the ANITA Experiment

Physical Review Letters, 2009

We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA... more We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of 3 EeV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultra-high energy extensive air showers.

Observations of the Askaryan Effect in Ice

Physical Review Letters, 2007

We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Chere... more We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations.

Observation of ultra-high-energy cosmic rays with the ANITA balloon-borne radio interferometer

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2010

We report the observation of sixteen cosmic ray events of mean energy of 1.5 × 10 19 eV, via radi... more We report the observation of sixteen cosmic ray events of mean energy of 1.5 × 10 19 eV, via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present the first ultra-wideband, far-field measurements of the radio spectral density of geosynchrotron emission in the range from 300-1000 MHz. The emission is 100% linearly polarized in the plane perpendicular to the projected geomagnetic field. Fourteen of our observed events are seen to have a phase-inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon.

Observations of microwave continuum emission from air shower plasmas

Physical Review D, 2008

We investigate a possible new technique for microwave detection of cosmic ray extensive air showe... more We investigate a possible new technique for microwave detection of cosmic ray extensive air showers which relies on detection of expected continuum radiation in the microwave range, caused by free-electron collisions with neutrals in the tenuous plasma left after the passage of the shower. We performed an initial experiment at the AWA (Argonne Wakefield Accelerator) laboratory in 2003 and measured broadband microwave emission from air ionized via high energy electrons and photons. A follow-up experiment at SLAC (Stanford Linear Accelerator Center) in summer of 2004 confirmed the major features of the previous AWA observations with better precision. Prompted by these results we built a prototype detector using satellite television technology, and have made measurements suggestive of detection of cosmic ray extensive air showers. The method, if confirmed by experiments now in progress, could provide a high-duty cycle complement to current nitrogen fluorescence observations.