Specification and testing of distributed software with executable state machines

Hajautettu järjestelmä koostuu useasta itsenäisesti toimivasta tietokonesovelluksesta, mikä tekee niiden määrittelystä ja testaamisesta haastavaa. Eräs haasteita tuottava osa on sovellusten välisen rajapinnan käyttö. XML-viesteillä kommunikoivassa järjestelmässä käytetyt viestit voidaan määritellä esimerkiksi XSD-skeemalla, mutta sillä ei voida määritellä sitä, miten viestejä tulee käyttää. Rajapinnan käytön määrittely on usein ihmisiä varten tehty, jolloin se voi olla puutteellinen ja suurpiirteinen. Tämän takia osaa sen toiminnoista ei välttämättä voida edes toteuttaa. Vaikka ne olisikin mahdollista toteuttaa, eri sovellusten kehittäjät voivat tulkita niiden käytön eri tavalla. Sovelluksia testatessakaan ei välttämättä ole varmuutta siitä toimiiko järjestelmä oikein, jos määritelmä antaa varaa tulkinnalle. Virhetilanteissa havaittu oire voi näkyä muussa kuin virheellisesti toimivassa sovelluksessa, joten virheen paikantaminen on myös työlästä. Tässä diplomityössä rajapintojen käyttö esitetään tilakoneina, joissa tilat kuvaavat kommunikaation sen hetkisen tilan ja tilasiirtymät kuvaavat mitä viestejä ja millä ehdoilla sovellukset saavat lähettää kussakin tilassa. Nämä tilakoneet määritellään koneluettavalla scxml-merkkauskielellä. Niiden lukemista sekä suorittamista varten toteutetaan tietokonesovellus, jonka tehtävä on valvoa sovellusten välistä viestiliikennettä ja todentaa sitä määritelmää vasten sekä raportoida virhetilanteista. Kommunikaatioprotokollan määrittely suoritettavilla tilakoneilla osoittautui toimivaksi ratkaisuksi järjestelmän kehityksen ja testauksen tukena. Järjestelmää testatessa se auttoi huomaamaan varmemmin ja paikantamaan nopeammin virheitä. Sillä havaittiin jopa virheitä, jotka eivät aiheuttaneet oireita järjestelmässä. Määrittely tilakoneilla pakottaa määrittelemään kaikki erikoistapauksetkin protokollan käytössä, jolloin rajapinnasta tulee huolellisemmin tehty. Kun järjestelmän voi tarkastaa suoraan määrittelyä vasten, ei määrittely myöskään ole irrallinen toteutuksesta, vaan molempien kehittäminen yhdessä on luontevaa

Radar—CubeSat Transionospheric HF Propagation Observations: Suomi 100 Satellite and EISCAT HF Facility

Radio waves provide a useful diagnostic tool to investigate the properties of the ionosphere because the ionosphere affects the transmission and properties of high frequency (HF) electromagnetic waves. We have conducted a transionospheric HF-propagation research campaign with a nanosatellite on a low-Earth polar orbit and the EISCAT HF transmitter facility in Tromsø, Norway, in December 2020. In the active measurement, the EISCAT HF facility transmitted sinusoidal 7.953 MHz signal which was received with the High frEquency rAdio spectRomEteR (HEARER) onboard 1 Unit (size: 10 × 10 × 10 cm) Suomi 100 space weather nanosatellite. Data analysis showed that the EISCAT HF signal was detected with the satellite's radio spectrometer when the satellite was the closest to the heater along its orbit. Part of the observed variations seen in the signal was identified to be related to the heater's antenna pattern and to the transmitted pulse shapes. Other observed variations can be related to the spatial and temporal variations of the ionosphere and its different responses to the used transmission frequencies and to the transmitted O- and X-wave modes. Some trends in the observed signal may also be associated to changes in the properties of ionospheric plasma resulting from the heater's electromagnetic wave energy. This paper is, to authors' best knowledge, the first observation of this kind of “self-absorption” measured from the transionospheric signal path from a powerful radio source on the ground to the satellite-borne receiver

Auroral imaging with combined Suomi 100 nanosatellite and ground-based observations: A case study

Auroras can be regarded as the most fascinating manifestation of space weather and they are continuously observed by ground-based and, nowadays more and more, also by space-based measurements. Investigations of auroras and geospace comprise the main research goals of the Suomi 100 nanosatellite, the first Finnish space research satellite, which has been measuring the Earth's ionosphere since its launch on Dec. 3, 2018. In this work, we present a case study where the satellite's camera observations of an aurora over Northern Europe are combined with ground-based observations of the same event. The analyzed image is, to the authors' best knowledge, the first auroral image ever taken by a cubesat. Our data analysis shows that a satellite vantage point provides complementary, novel information of such phenomena. The 3D auroral location reconstruction of the analyzed auroral event demonstrates how information from a 2D image can be used to provide location information of auroras under study. The location modelling also suggests that the Earth's limb direction, which was the case in the analyzed image, is an ideal direction to observe faint auroras. Although imaging on a small satellite has some large disadvantages compared with ground-based imaging (the camera cannot be repaired, a fast moving spinning satellite), the data analysis and modelling demonstrate how even a small 1-Unit (size: 10 cm x 10 cm x 10 cm) CubeSat and its camera, build using cheap commercial off-the-shelf components, can open new possibilities for auroral research, especially, when its measurements are combined with ground-based observations.Comment: Accepted manuscript 34 pages, 17 figure

Rattijuopon profiili ja uusimisen riskitekijät: Tuloksia rattijuopumuksen esiintyvyydestä ja kehityksestä Uudenmaan ratsiatutkimuksesta vuosina 1990-2008

<p><b>Stay probability patterns predicted by simulating model-free (A), model-based (B), and hybrid (C) reinforcement learning algorithms.</b> Stay probability measures the probability of choosing the first-level action that results in the same second-level state as the previous trial. This index was measured for trials under four conditions: whether the reward received in the previous trial was “high” or “low”, and whether the transition experienced in the previous trial (relative to the trial before that) had its contingency “changed” or remained “fixed”. Stay probabilities are plotted for trials following a change trial that started at the second level, as only these distinguish model-free and model-based strategies. For the hybrid model (C), the parameter <i>wMB</i> was set to 0.56, the median value of the parameter inferred from participants’ behavior. * <i>p</i> < 0.05, ** <i>p</i> < 0.01.</p

Radar – CubeSat Transionospheric HF Propagation Observations: Suomi 100 Satellite and EISCAT HF Facility

Radio waves provide a useful diagnostic tool to investigate the properties of the ionosphere because the ionosphere affects the transmission and properties of High Frequency (HF) electromagnetic waves. We have conducted a transionospheric HF-propagation research campaign with a nanosatellite on a low-Earth polar orbit and the EISCAT HF transmitter facility in Tromsø, Norway, in December 2020. In the active measurement, the EISCAT HF facility transmitted sinusoidal 7.953 MHz signal which was received with the HEARER radio spectrometer onboard 1 Unit (size: 10 cm × 10 cm × 10 cm) Suomi 100 space weather nanosatellite. Data analysis showed that the EISCAT HF signal was detected with the satellite’s radio spectrometer when the satellite was the closest to the heater along its orbit. Part of the observed variations seen in the signal was identified to be related to the heater’s antenna pattern and to the transmitted pulse shapes. Other observed variations can be related to the spatial and temporal variations of the ionosphere and its different responses to the used transmission frequencies and to the transmitted O- and X-wave modes. Some trends in the observed signal may also be associated to changes in the properties of ionospheric plasma resulting from the heater’s electromagnetic wave energy. This paper is, to authors’ best knowledge, the first observation of this kind of "self-absorption" measured from the transionospheric signal path from a powerful radio source on the ground to the satellite-borne receiver.Peer reviewe

GAMEHIGHED Initial Report : Output 1: Initial Research & Analysis Report. Higher-ed Programmes for Careers in Game Design & Development (2019–2022)

nonPeerReviewe

Radar—CubeSat transionospheric HF propagation observations:Suomi 100 satellite and EISCAT HF facility

Abstract Radio waves provide a useful diagnostic tool to investigate the properties of the ionosphere because the ionosphere affects the transmission and properties of high frequency (HF) electromagnetic waves. We have conducted a transionospheric HF-propagation research campaign with a nanosatellite on a low-Earth polar orbit and the EISCAT HF transmitter facility in Tromsø, Norway, in December 2020. In the active measurement, the EISCAT HF facility transmitted sinusoidal 7.953 MHz signal which was received with the High frEquency rAdio spectRomEteR (HEARER) onboard 1 Unit (size: 10 × 10 × 10 cm) Suomi 100 space weather nanosatellite. Data analysis showed that the EISCAT HF signal was detected with the satellite’s radio spectrometer when the satellite was the closest to the heater along its orbit. Part of the observed variations seen in the signal was identified to be related to the heater’s antenna pattern and to the transmitted pulse shapes. Other observed variations can be related to the spatial and temporal variations of the ionosphere and its different responses to the used transmission frequencies and to the transmitted O- and X-wave modes. Some trends in the observed signal may also be associated to changes in the properties of ionospheric plasma resulting from the heater’s electromagnetic wave energy. This paper is, to authors’ best knowledge, the first observation of this kind of “self-absorption” measured from the transionospheric signal path from a powerful radio source on the ground to the satellite-borne receiver

Nuorten liikuntakäyttäytyminen Suomessa : LIITU-tutkimuksen tuloksia 2020

nonPeerReviewe