Browsing by Subject "measurement"
Now showing items 1-6 of 6
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(2023)The purpose of this study was to assess the best way to measure carpal alignment. The study compared computer-based measurements and manual measurements of the carpal alignment. The subjects of comparison were the methods of measuring the radioscaphoid, radiolunate, radiocapitate and radiometacarpal angles. 30 cone beam CT scans of healthy, uninjured, wrists were analyzed by automated software (Disior ltd) and by hand surgeons using lateral radiographs reconstructed from the CT scans. Six hand surgeons were given instructions on how to take the measurements. They analyzed both reconstructed radiographs in which the wrist bones were partially overlapping due to summation, and reconstructed radiographs, where overlapping of the wrist bones had been digitally removed. In addition, seven different hand surgeons were not given instructions on the measurement methods. They analyzed only the reconstructed radiographs with wrist bones overlapping. In manual measurements, the inter- and intra-observer reliability of the results varied from good to excellent (ICC: 0.77–0.99), both in the instructed and in the uninstructed group. Inter-observer reliability was better in the group instructed in the methods of measurement. Reliability was further improved in reconstructed radiographs where the overlapping of the carpal bones had been digitally removed. Intra-observer reliability was very similar in both the instructed and uninstructed groups, and improved when bony overlapping was removed. The software provided excellent intra-observer reliability (ICC 0.94-1.00) and result, that were highly comparable the instructed manual measurements from radiographs with no bony overlapping (mean difference range 1°-7°). Although statistically significant differences were seen between manual measurements and software measurements, the differences are too small to be clinically significant. The research shows that accurate and repeatable computer-aided measurements of the carpal alignment can be made from CT scans, thereby minimizing observational errors. Key words: Carpal alignment, measurement, reliability, computer-aided, digitally reconstructed radiographs
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(2022)The variational quantum eigensolver (VQE) is one of the most promising proposals for a hybrid quantum-classical algorithm made to take advantage of near-term quantum computers. With the VQE it is possible to find ground state properties of various of molecules, a task which many classical algorithms have been developed for, but either become too inaccurate or too resource-intensive especially for so called strongly correlated problems. The advantage of the VQE comes in the ability of a quantum computer to represent a complex system with fewer so-called qubits than a classical computer would with bits, thus making the simulation of large molecules possible. One of the major bottlenecks for the VQE to become viable for simulating large molecules however, is the scaling of the number of measurements necessary to estimate expectation values of operators. Numerous solutions have been proposed including the use of adaptive informationally complete positive operator-valued measures (IC-POVMs) by García-Pérez et al. (2021). Adaptive IC-POVMs have shown to improve the precision of estimations of expectation values on quantum computers with better scaling in the number of measurements compared to existing methods. The use of these adaptive IC-POVMs in a VQE allows for more precise energy estimations and additional expectation value estimations of separate operators without any further overhead on the quantum computer. We show that this approach improves upon existing measurement schemes and adds a layer of flexibility, as IC-POVMs represent a form of generalized measurements. In addition to a naive implementation of using IC-POVMs as part of the energy estimations in the VQE, we propose techniques to reduce the number of measurements by adapting the number of measurements necessary for a given energy estimation or through the estimation of the operator variance for a Hamiltonian. We present results for simulations using the former technique, showing that we are able to reduce the number of measurements while retaining the improvement in the measurement precision obtained from IC-POVMs.
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(2019)Ruukkusalaattien tuotanto on kasvanut Suomessa jo vuosikymmeniä. Kasvihuoneet mahdollistavat tuoreiden lehtivihannesten kasvatuksen ympärivuotisesti, mutta pimeä vuodenaika tai valonsaannin heikentyminen yhdessä korkean nitraattilannoituksen kanssa aiheuttavat nitraatin kertymistä salaattiin. Nitraatti ei itsessään ole kovin myrkyllistä ihmiselle, mutta sen aineenvaihduntatuotteet elimistössä voivat olla haitallisia. Siksi ravinnon nitraattipitoisuuksia rajoitetaan EU asetuksella ja kasvisten nitraattipitoisuuksia valvoo Ruokavirasto. Tutkimuksen tavoitteena oli selvittää jääsalaatin (Lactuca sativa L.) nitraattipitoisuuteen vaikuttavia tekijöitä yksityisellä kasvihuonepuutarhalla, ja ehdottaa helposti sovellettavia keinoja nitraattipitoisuuden alentamiseksi. Tutkimuksessa mitattiin vuorokaudenajan, iän ja olosuhteiden vaikutusta jääsalaatin nitraattipitoisuuteen. Mittaukset tehtiin eri kellonaikoina korjatuilta salaateilta, neljän, viiden ja kuuden viikon ikäisiltä salaateilta, sekä viikoittaisilla seurantamittauksilla kolmen kuukauden ajan syksyllä 2017. Salaattien nitraattipitoisuus määriteltiin pikamittausmenetelmällä. Kasveille tulevaa PAR-valoa ja kiertoliuoksen nitraattityppipitoisuutta mitattiin jatkuvatoimisella mittalaitteella. Lisäksi kasvihuoneen automaattisesta ohjausjärjestelmästä saatiin tietoa muista kasvuolosuhteista. Sadonkorjuun kellonaika ei vaikuttanut jääsalaatin nitraattipitoisuuteen. Ikä vaikutti neljän ja viiden viikon ikäisten salaattien nitraattipitoisuuteen, mutta paremmissa valo-olosuhteissa iän vaikutus heikkeni kuuden viikon ikäisillä salaateilla. Nitraattityppilannoituksella ei ollut suoraa vaikutusta salaatin nitraattipitoisuuteen, mutta enemmän valoa saaneissa salaateissa oli vähemmän nitraattia. Kasvuston tasolta tehdystä jatkuvatoimisesta valon mittauksesta on hyötyä salaatin nitraattipitoisuuden hallinnassa. Riski nitraatin enimmäispitoisuusrajan ylitykseen on suuri syyskuussa luonnonvalon määrän vähentyessä. Tekovalojen käytön lisäämisellä voidaan alentaa salaatin nitraattipitoisuutta.
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(2020)The impacts of dust aerosols on human health and climate change are increasing as the particulate matter (PM) mass concentrations and frequency of Sand and Dust Storm (SDS) episodes have shown an increasing trend in recent studies, especially for the Middle East and North Africa (MENA). In this thesis, particulate matter (PM10 and PM2.5) concentrations were measured during May 2018–March 2019 in the urban atmosphere of Amman, Jordan. The PM sampling was 24-hours every 6 days. The overall mean PM10 mass concentration was 64±39 μg/m3 with the median (+interquartile range) value of 49.2+53.5 μg/m3, the PM2.5 mass concentration varied between 15 μg/m3 and 190 μg/m3 with an annual average 47±32 μg/m3 and with the median (+interquartile range) value of 35.8+26.3 μg/m3. The PM2.5 / PM10 ratio was 0.8±0.2. According to the Jordanian Air Quality standards, the annual mean PM10 needs to be below a limit value of 120 μg/m3, which was true in this work. However, the PM2.5 mass concentration was three times higher the corresponding limit value (65 μg/m3). However, both exceeded the World Health Organization (WHO) air quality annual guideline of 20 μg/m3 for PM10 and 10 μg/m3 for PM2.5. The results show that the observed PM10 mass concentrations in Jordan were lower than what was reported in other cities in the Middle East but were higher when compared to other Mediterranean cities. During the measurement period, Jordan was affected by Sand and Dust Storms (SDS), which were observed on 14 sampling days. The source origins of these SDS were traced back to North Africa, the Arabian Peninsula, and the Levant. The 24-hour PM10 concentrations during these SDS episodes ranged between 108.1 μg/m3 and 187.3 μg/m3. In the future, measurements with a higher time resolution (one sample per day) are recommended for a more precise seasonal trend interpretation.
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(2021)The natural carbon cycle is affected by human activity. Terrestrial carbon stocks have been decreasing as at the same time carbon dioxide concentration in the atmosphere has increased causing climate change. The Paris Agreement sets the target to limit climate change to 1.5°C and to reach that goal, all possible mitigation practises should be included into global framework to avoid the most serious consequences of warming. Carbon sequestration into natural soil and biomass could be one mitigation practice. To enhance carbon sequestration activities and to include natural carbon stocks into to the EU climate policy, it would be necessary to quantify stock sizes and changes in those stocks. For developing carbon trading markets, the quantification methods should provide accurate results and at the same time be practical and financially achievable. Used research method in this thesis was comparatively literature survey and aim was to gather and compere information about currently used carbon stock quantification methods against developing carbon trading markets. Soil carbon stocks can be quantified with direct soil sampling, spectroscopic sensing methods or by mathematical models. Biomass carbon stocks can be quantified with inventory-based field measurements and modelling and by remote sensing. The full carbon budget on the ecosystem level can be achieved with carbon flux measurements. Quantification of different terrestrial carbon stocks and their changes is not a simple task. There is a lot of variation between different stocks and in some cases, the stock changes occur slow. Cost of carbon stock quantification depends on the accuracy, size of the area under focus and frequency of the measures. Methods for terrestrial carbon stock quantification are dependent on high quality data and there is demand for research considering carbon sequestration. For carbon offsetting purposes of developing carbon markets, the modelling approach is achievable, cost efficient, repeatable and transparent. There is no perfect model or one universal model that would fit to every situation and thus the differences must be known. At this stage, this approach could be one possibility to include small scale projects and enhance climate actions. Different quantification methods provide information which can be used to different method developments and to increase accuracies. It’s important to know, how all information can be effectively utilized.
Now showing items 1-6 of 6