Lajittelun laadun hallinta

Tässä diplomityössä tarkastellaan kuumahierteen lajittimien akseptimassan laadun hallintaan vaikuttavia tekijöitä. Tarkastelussa keskitytään pääasiassa roottorin pyörintänopeuden ja syöttösakeuden vaikutukseen lajittimien lajittelutuloksiin. Lisäksi työssä tarkastellaan lajittimen roottorin pyörintänopeuden muuttamiseen perustuvaa akseptimassan freeness-säädön toimintaa ja sen käyttökelpoisuutta akseptimassan freeness-tason hallitsemiseksi. Tulosten perusteella painelajittimien roottorin pyörintänopeudella on vaikutusta aksepti- ja rejektimassan laatuominaisuuksiin. Roottorin pyörintänopeuden muuttamiseen perustuva akseptimassan freeness-tason säätö on periaatteeltaan toimiva. Säätö toimii parhaiten tilanteissa, joissa lajittimen syöttömassan freeness nousee. Tarkastelujakson aikana roottorin pyörintänopeussäätö oli uusi, lisäksi lajittelussa tehtiin muutakin säätökehitystä, joten se miten paljon säädöstä on hyötyä freeness-huojunnan tasaajana, jäi selvittämättä. Työssä osoitettiin myös se, että syöttösakeudella voidaan vaikuttaa akseptimassan freeness-tasoon. Vaikutus ei ole kuitenkaan yhtä selkeä kuin roottorin pyörintänopeussäädön.

Single breath-hold 3D measurement of left atrial volume using compressed sensing cardiovascular magnetic resonance and a non-model-based reconstruction approach.

BACKGROUND: Left atrial (LA) dilatation is associated with a large variety of cardiac diseases. Current cardiovascular magnetic resonance (CMR) strategies to measure LA volumes are based on multi-breath-hold multi-slice acquisitions, which are time-consuming and susceptible to misregistration. AIM: To develop a time-efficient single breath-hold 3D CMR acquisition and reconstruction method to precisely measure LA volumes and function. METHODS: A highly accelerated compressed-sensing multi-slice cine sequence (CS-cineCMR) was combined with a non-model-based 3D reconstruction method to measure LA volumes with high temporal and spatial resolution during a single breath-hold. This approach was validated in LA phantoms of different shapes and applied in 3 patients. In addition, the influence of slice orientations on accuracy was evaluated in the LA phantoms for the new approach in comparison with a conventional model-based biplane area-length reconstruction. As a reference in patients, a self-navigated high-resolution whole-heart 3D dataset (3D-HR-CMR) was acquired during mid-diastole to yield accurate LA volumes. RESULTS: Phantom studies. LA volumes were accurately measured by CS-cineCMR with a mean difference of -4.73 ± 1.75 ml (-8.67 ± 3.54%, r2 = 0.94). For the new method the calculated volumes were not significantly different when different orientations of the CS-cineCMR slices were applied to cover the LA phantoms. Long-axis "aligned" vs "not aligned" with the phantom long-axis yielded similar differences vs the reference volume (-4.87 ± 1.73 ml vs. -4.45 ± 1.97 ml, p = 0.67) and short-axis "perpendicular" vs. "not-perpendicular" with the LA long-axis (-4.72 ± 1.66 ml vs. -4.75 ± 2.13 ml; p = 0.98). The conventional bi-plane area-length method was susceptible for slice orientations (p = 0.0085 for the interaction of "slice orientation" and "reconstruction technique", 2-way ANOVA for repeated measures). To use the 3D-HR-CMR as the reference for LA volumes in patients, it was validated in the LA phantoms (mean difference: -1.37 ± 1.35 ml, -2.38 ± 2.44%, r2 = 0.97). Patient study: The CS-cineCMR LA volumes of the mid-diastolic frame matched closely with the reference LA volume (measured by 3D-HR-CMR) with a difference of -2.66 ± 6.5 ml (3.0% underestimation; true LA volumes: 63 ml, 62 ml, and 395 ml). Finally, a high intra- and inter-observer agreement for maximal and minimal LA volume measurement is also shown. CONCLUSIONS: The proposed method combines a highly accelerated single-breathhold compressed-sensing multi-slice CMR technique with a non-model-based 3D reconstruction to accurately and reproducibly measure LA volumes and function.

Quantifying the time for accurate EEG decoding of single value-based decisions.

BACKGROUND: Recent neuroimaging studies suggest that value-based decision-making may rely on mechanisms of evidence accumulation. However no studies have explicitly investigated the time when single decisions are taken based on such an accumulation process. NEW METHOD: Here, we outline a novel electroencephalography (EEG) decoding technique which is based on accumulating the probability of appearance of prototypical voltage topographies and can be used for predicting subjects' decisions. We use this approach for studying the time-course of single decisions, during a task where subjects were asked to compare reward vs. loss points for accepting or rejecting offers. RESULTS: We show that based on this new method, we can accurately decode decisions for the majority of the subjects. The typical time-period for accurate decoding was modulated by task difficulty on a trial-by-trial basis. Typical latencies of when decisions are made were detected at ∼500ms for 'easy' vs. ∼700ms for 'hard' decisions, well before subjects' response (∼340ms). Importantly, this decision time correlated with the drift rates of a diffusion model, evaluated independently at the behavioral level. COMPARISON WITH EXISTING METHOD(S): We compare the performance of our algorithm with logistic regression and support vector machine and show that we obtain significant results for a higher number of subjects than with these two approaches. We also carry out analyses at the average event-related potential level, for comparison with previous studies on decision-making. CONCLUSIONS: We present a novel approach for studying the timing of value-based decision-making, by accumulating patterns of topographic EEG activity at single-trial level.

Kulmastabiilisuuden mallinnus

Työn tavoitteena oli kartoittaa vaihtoehtoisia menetelmiä perinteiselle aikatasossa tapahtuvalle kulmastabiilisuuden mallinnukselle käyttövarmuustarkastelussa. Vaihtoehtoisiin menetelmiin tutustuttiin kirjallisuuden avulla ja valittiin menetelmä testattavaksi pohjoismaisessa yhteiskäyttöjärjestelmässä. Vaihtoehtoisen menetelmän ominaisuusvaatimuksiin kuului nopeampi laskenta, luotettava stabiilien ja epästabiilien tilanteiden seulontakyky ja menetelmän antama indeksi stabiilisuus-/epästabiilisuusasteesta. Pääasiassa menetelmät, joihin tutustuttiin, arvioivat vain transienttia stabiilisuutta. SIME-menetelmä soveltui myös dynaamisen stabiilisuuden arviointiin. Suomessa voi dynaamisella stabiilisuudella olla tulevaisuudessa merkittävä rooli käyttövarmuustarkasteluissa. SIME-menetelmän toimivuutta testattiin osin yksinkertaistetulla Nordel-verkkomallilla, ja saadut tulokset olivat lupaavia. Menetelmä täytti uudelle menetelmälle asetetut vaatimukset, vaikka ongelmiakin esiintyi. Testauksessa käytetyn menetelmän edelleen kehittäminen ja menetelmän testaaminen täydellisellä verkkomallilla on suositeltavaa.

Business Process Modeling in Software Requirements Engineering for Small and Medium Software Projects

Vaatimusmäärittelyn tavoitteena on luoda halutun järjestelmän kokonaisen, yhtenäisen vaatimusluettelon vaatimusten määrittämiseksi käsitteellisellä tasolla. Liiketoimintaprosessien mallintaminen on varsin hyödyllinen vaatimusmäärittelyn varhaisissa vaiheissa. Tämä työ tutkii liiketoimintaprosessien mallintamista tietojärjestelmien kehittämistä varten. Nykyään on olemassa erilaisia liiketoimintaprosessien mallintamiseen tarkoitettuja tekniikoita. Tämä työ tarkastaa liiketoimintaprosessien mallintamisen periaatteet ja näkökohdat sekä eri mallinnustekniikoita. Uusi menetelmä, joka on suunniteltu erityisesti pienille ja keskisuurille ohjelmistoprojekteille, on kehitetty prosessinäkökohtien ja UML-kaavioiden perusteella.

Virtuaaliprototyypin käyttö kallioporakoneen dynamiikan analysoinnissa

Työn tavoitteena oli selvittää kaupallisen dynamiikan simulointiohjelmiston soveltuvuus kallioporakoneen dynamiikan analysointiin. Työssä mallinnettiin parametrisoitu virtuaaliprototyyppi uudenlaisella toimintaperiaatteella toimivasta kallioporakoneesta. Virtuaaliprototyyppiä on tarkoitus käyttää fyysisen prototyypin mitoituksessa sekä porakoneen toiminnan simuloinnissa ja suorituskyvyn arvioinnissa ennen ensimmäisen fyysisen prototyypin valmistamista. Mallinnus tehtiin ADAMS -ohjelmistoa ja siihen liitettävää ADAMS/Hydraulics -moduulia käyttäen. Mallinnuksessa kiinnitettiin huomiota erityisesti porakoneessa esiintyvien vuotovirtauksien huomioimiseen. ADAMS -ohjelmisto soveltuu hyvin hydraulisen iskuporakoneen dynaamisten ilmiöiden simulointiin. Koska fyysistä prototyyppiä ei ole vielä olemassa, ei mallin toimintaa voida kuitenkaan tämän tutkimuksen puitteissa verifioida mittauksin. Simuloitujen tulosten perusteella voidaan todeta uuden toimintaperiaatteen olevan käyttökelpoinen kallion poraukseen. Parametrisoitua virtuaaliprototyyppiä voidaan käyttää tehokkaasti hyväksi tuotekehitysvaiheessa sekä se voidaan liittää osaksi laajempaa ja yksityiskohtaisempaa porauslaitteen simulointimallia.

Populaation monimuotoisuuden mittaaminen liukulukukoodatuissa evoluutioalgoritmeissa

Diplomityössä esitetään menetelmä populaation monimuotoisuuden mittaamiseen liukulukukoodatuissa evoluutioalgoritmeissa, ja tarkastellaan kokeellisesti sen toimintaa. Evoluutioalgoritmit ovat populaatiopohjaisia menetelmiä, joilla pyritään ratkaisemaan optimointiongelmia. Evoluutioalgoritmeissa populaation monimuotoisuuden hallinta on välttämätöntä, jotta suoritettu haku olisi riittävän luotettavaa ja toisaalta riittävän nopeaa. Monimuotoisuuden mittaaminen on erityisen tarpeellista tutkittaessa evoluutioalgoritmien dynaamista käyttäytymistä. Työssä tarkastellaan haku- ja tavoitefunktioavaruuden monimuotoisuuden mittaamista. Toistaiseksi ei ole ollut olemassa täysin tyydyttäviä monimuotoisuuden mittareita, ja työn tavoitteena on kehittää yleiskäyttöinen menetelmä liukulukukoodattujen evoluutioalgoritmien suhteellisen ja absoluuttisen monimuotoisuuden mittaamiseen hakuavaruudessa. Kehitettyjen mittareiden toimintaa ja käyttökelpoisuutta tarkastellaan kokeellisesti ratkaisemalla optimointiongelmia differentiaalievoluutioalgoritmilla. Toteutettujen mittareiden toiminta perustuu keskihajontojen laskemiseen populaatiosta. Keskihajonnoille suoritetaan skaalaus, joko alkupopulaation tai nykyisen populaation suhteen, riippuen lasketaanko absoluuttista vai suhteellista monimuotoisuutta. Kokeellisessa tarkastelussa havaittiin kehitetyt mittarit toimiviksi ja käyttökelpoisiksi. Tavoitefunktion venyttäminen koordinaattiakseleiden suunnassa ei vaikuta mittarin toimintaan. Myöskään tavoitefunktion kiertäminen koordinaatistossa ei vaikuta mittareiden tuloksiin. Esitetyn menetelmän aikakompleksisuus riippuu lineaarisesti populaation koosta, ja mittarin toiminta on siten nopeaa suuriakin populaatioita käytettäessä. Suhteellinen monimuotoisuus antaa vertailukelpoisia tuloksia riippumatta parametrien lukumäärästä tai populaation koosta.

Estimación de funciones no lineales en mezclas post-no lineales

This paper proposes a new method for blindly inverting a nonlinear mapping which transforms a sum of random variables. This is the case of post-nonlinear (PNL) source separation mixtures. The importance of the method is based on the fact that it permits to decouple the estimation of the nonlinear part from the estimation of the linear one. Only the nonlinear part is inverted, without considering on the linear part. Hence the initial problem is transformed into a linear one that can then be solved with any convenient linear algorithm. The method is compared with other existing algorithms for blindly approximating nonlinear mappings. Experiments show that the proposed algorithm outperforms the results obtained with other algorithms and give a reasonably good linearized data

Spatial radial maze procedures and setups to dissociate local and distal relational spatial frameworks in humans.

BACKGROUND: Radial maze tasks have been used to assess optimal foraging and spatial abilities in rodents. The spatial performance was based on a capacity to rely on a configuration of local and distant cues. We adapted maze procedures assessing the relative weight of local cues and distant landmarks for arm choice in humans. NEW METHOD: The procedure allowed testing memory of places in four experimental setups: a fingertip texture-groove maze, a tactile screen maze, a virtual radial maze and a walking size maze. During training, the four reinforced positions remained fixed relative to local and distal cues. During subsequent conflict trials, these frameworks were made conflictive in the prediction of reward locations. RESULTS: Three experiments showed that the relative weight of local and distal relational cues is affected by different factors such as cues' nature, visual access to the environment, real vs. virtual environment, and gender. A fourth experiment illustrated how a walking maze can be used with people suffering intellectual disability. COMPARISON WITH EXISTING METHODS: In our procedure, long-term (reference) and short-term (working) memory can be assessed. It is the first radial task adapted to human that enables dissociating local and distal cues, to provides an indication as to their relative salience. Our mazes are moveable and easily used in limited spaces. Tasks are performed with realistic and spontaneous though controlled exploratory movements. CONCLUSION: Our tasks enabled highlighting the use of different strategies. In a clinical perspective, considering the use of compensatory strategies should orient towards adapted behavioural rehabilitation.

Fluid dynamical prediction of changed v1-flow at energies available at the CERN Large Hadron Collider

Substantial collective flow is observed in collisions between lead nuclei at Large Hadron Collider (LHC) as evidenced by the azimuthal correlations in the transverse momentum distributions of the produced particles. Our calculations indicate that the global v1-flow, which at RHIC peaked at negative rapidities (named third flow component or antiflow), now at LHC is going to turn toward forward rapidities (to the same side and direction as the projectile residue). Potentially this can provide a sensitive barometer to estimate the pressure and transport properties of the quark-gluon plasma. Our calculations also take into account the initial state center-of-mass rapidity fluctuations, and demonstrate that these are crucial for v1 simulations. In order to better study the transverse momentum flow dependence we suggest a new"symmetrized" vS1(pt) function, and we also propose a new method to disentangle global v1 flow from the contribution generated by the random fluctuations in the initial state. This will enhance the possibilities of studying the collective Global v1 flow both at the STAR Beam Energy Scan program and at LHC.

Monikanavaisuuden hyödyt ja haitat - tutkimus monikanavaisuudesta palveluntarjoajan ja asiakkaan näkökulmasta

Tämän tutkimuksen tavoitteena oli selvittää, voidaanko asiakkaan ja palveluntarjoajan odotukset yhdistää muodostettaessa palveluntarjoajan monikanavamallia. Monikanavaisuus tuo asiakkaalle mahdollisuuksia ajasta ja paikasta riippumattomaan asiointiin. Asiakkaan näkökulmasta tämä tarkoittaa usein sitä, että hänen oppimansa asiointitapa muuttuu. Asiakas kokee haittana sen, että joutuu panostamaan uuden asiointitavan opettelemiseen ja odottaa tämän muutoksen tuovan hänelle hyötyjä. Monikanavaisuuden hyödyt asiakkaalle punnitaan tässä muutostilanteessa. Palveluntarjoaja odottaa monikanavamallin tuovan kustannussäästöjä, sillä kanavavalinnat ovat keino kehittää asiakkuuksia ja vaikuttaa yrityksen kannattavuuteen pitkällä aikajänteellä. Monikanavamallin toteuttaminen vaatii palveluntarjoajalta alkuvaiheessa resursseja, investointeja ja halutun muutoksen tavoitteellista johtamista. Tutkittavat asiakkaat valittiin Suomen Posti Oyj:n Yritykset ja yritykset –asiakassegmentistä. Tutkimuksessa ei löytynyt asiakaskohtaisia eroja asiakkaiden odotuksista palveluntarjoajien monikanavamalleihin, mutta hyötyodotusten suhteen tunnistettiin kolme erilaista asiakastyyppiä: kustannussäästöjä odottavat hintaorientoituneet asiakkaat, palvelun entistä parempaa sujumista odottavat palveluorientoituneet asiakkaat ja oman valinnanvapautensa merkitystä painottavat asiakassuhdeorientoituneet asiakkaat. Palveluntarjoajan tulee pystyä viestimään ja argumentoimaan asiointitavan muutoksesta kullekin asiakkaalle merkityksellisellä tavalla. Teorian ja empirian pohjalta voidaan sanoa, että asiakkaan ja palveluntarjoajan odotukset voidaan yhdistää muodostettaessa palveluntarjoajan monikanavamallia. Tämä edellyttää, että palveluntarjoaja tuntee asiakkaansa niin hyvin, että tietää millaiset eri asiakkaiden hyötyodotukset ovat.

Elinkaarianalyysin soveltaminen käyttökustannuslaskennassa ja kilpailijavertailussa

The aim of this master’s thesis is to develop a calculation form that can be utilized in studying life cycle costs of different products. This research will especially focus on competing products with different cost structures. The calculation form introduced here will then be applied to calculate the operation costs of green mowers in terms of the life cycle method.The research contains an introduction to the field of study and its specific features. The main questions are how to construct a frame of reference and how to find an effective way to combine life cycle assessment and calculation with management accounting. The empirical part of the research concentrated on studying operation costs of green mowers in different working situations. The results were critically analyzed and the effectivity of the new calculation form was estimated.The present study shows that this new method is effective in giving information on life cycle costs. The results concerning the green mowers were not simple but depended on several factors. In any case it is possible to say that the new type of the green mower is very competitive against the traditional green mowers.

On the robust measurement of inflectional diversity

Lexical diversity measures are notoriously sensitive to variations of sample size and recent approaches to this issue typically involve the computation of the average variety of lexical units in random subsamples of fixed size. This methodology has been further extended to measures of inflectional diversity such as the average number of wordforms per lexeme, also known as the mean size of paradigm (MSP) index. In this contribution we argue that, while random sampling can indeed be used to increase the robustness of inflectional diversity measures, using a fixed subsample size is only justified under the hypothesis that the corpora that we compare have the same degree of lexematic diversity. In the more general case where they may have differing degrees of lexematic diversity, a more sophisticated strategy can and should be adopted. A novel approach to the measurement of inflectional diversity is proposed, aiming to cope not only with variations of sample size, but also with variations of lexematic diversity. The robustness of this new method is empirically assessed and the results show that while there is still room for improvement, the proposed methodology considerably attenuates the impact of lexematic diversity discrepancies on the measurement of inflectional diversity.

Proportionality and Party Success in Europe

This thesis consists of four articles and an introductory section. The main research questions in all the articles are about proportionality and party success in Europe, at European, national or district levels. Proportionality in this thesis denotes the proximity of seat shares parties receive compared to their respective vote shares, after the electoral system’s allocation process. This proportionality can be measured through numerous indices that illustrate either the overall proportionality of an electoral system or a particular election. The correspondence of a single party’s seat shares to its vote shares can also be measured. The overall proportionality is essential in three of the articles (1, 2 and 4), where the system’s performance is studied by means of plots. In article 3, minority party success is measured by advantage-ratios that reveal single party’s winnings or losses in the votes to seat allocation process. The first article asks how proportional are the European parliamentary (EP) electoral systems, how do they compare with results gained from earlier studies and how do the EP electoral systems treat different sized parties. The reasons for different outcomes are looked for in explanations given by traditional electoral studies i.e. electoral system variables. The countries studied (EU15) apply electoral systems that vary in many important aspects, even though a certain amount of uniformity has been aspired to for decades. Since the electoral systems of the EP elections closely resemble the national elections, the same kinds of profiles emerge as in the national elections. The electoral systems indeed treat the parties differentially and six different profile types can be found. The counting method seems to somewhat determine the profile group, but the strongest variables determining the shape of a countries’ profile appears to be the average district magnitude and number of seats allocated to each country. The second article also focuses on overall proportionality performance of an electoral system, but here the focus is on the impact of electoral system changes. I have developed a new method of visualizing some previously used indices and some new indices for this purpose. The aim is to draw a comparable picture of these electoral systems’ changes and their effects. The cases, which illustrate this method, are four elections systems, where a change has occurred in one of the system variables, while the rest remained unchanged. The studied cases include the French, Greek and British European parliamentary systems and the Swedish national parliamentary system. The changed variables are electoral type (plurality changed to PR in the UK), magnitude (France splitting the nationwide district into eight smaller districts), legal threshold (Greece introducing a three percent threshold) and counting method (d’Hondt was changed to modified Sainte-Laguë in Sweden). The radar plots from elections after and before the changes are drawn for all country cases. When quantifying the change, the change in the plots area that is created has also been calculated. Using these radar plots we can observe that the change in electoral system type, magnitude, and also to some extent legal threshold had an effect on overall proportionality and accessibility for small parties, while the change between the two highest averages counting method had none. The third article studies the success minority parties have had in nine electoral systems in European heterogeneous countries. This article aims to add more motivation as to why we should care how different sized parties are treated by the electoral systems. Since many of the parties that aspire to represent minorities in European countries are small, the possibilities for small parties are highlighted. The theory of consociational (or power-sharing) democracy suggests that, in heterogeneous societies, a proportional electoral system will provide the fairest treatment of minority parties. The OSCE Lund Recommendations propose a number of electoral system features, which would improve minority representation. In this article some party variables, namely the unity of the minority parties and the geographical concentration of the minorities were included among possible explanations. The conclusions are that the central points affecting minority success were indeed these non-electoral system variables rather than the electoral system itself. Moreover, the size of the party was a major factor governing success in all the systems investigated; large parties benefited in all the studied electoral systems. In the fourth article the proportionality profiles are again applied, but this time to district level results in Finnish parliamentary elections. The level of proportionality distortion is also studied by way of indices. The average magnitudes during the studied periodrange from 7.5 to 26.2 in the Finnish electoral districts and this opens up unequal opportunities for parties in different districts and affects the shape of the profiles. The intra-country case allows the focus to be placed on the effect of district magnitude, since all other electoral systems are kept constant in an intra-country study. The time span in the study is from 1962 to 2007, i.e. the time that the districts have largely been the same geographically. The plots and indices tell the same story, district magnitude and electoral alliances matter. The district magnitude is connected to the overall proportionality of the electoral districts according to both indices, and the profiles are, as expected, also closer to perfect proportionality in large districts. Alliances have helped some small parties to gain a much higher seat share than their respective vote share and these successes affect some of the profiles. The profiles also show a consistent pattern of benefits for the small parties who ally with the larger parties.

Comparative Effect of a Renin Inhibitor and a Thiazide Diuretic on Renal Tissue Oxygenation in Hypertensive Patients.

BACKGROUND/AIMS: The purpose of the present study was to compare the direct renin inhibitor aliskiren to the diuretic hydrochlorothiazide (HCTZ) in their ability to modulate renal tissue oxygenation in hypertensive patients. METHODS: 24 patients were enrolled in this randomized prospective study and 20 completed the protocol. Patients were randomly assigned to receive either aliskiren 150-300 mg/d or HCTZ 12.5 - 25 mg/d for 8 weeks. Renal oxygenation was measured by BOLD-MRI at weeks 0 and 8. BOLD-MRI was also performed before and after an i.v. injection of 20 mg furosemide at week 0 and at week 8. BOLD-MRI data were analyzed by measuring the oxygenation in 12 computed layers of the kidney enabling to asses renal oxygenation according to the depth within the kidney and by the classical method of regions of interest (ROI). RESULTS: The classical ROI analysis of the data showed no difference between the groups at week 8. The analysis of renal oxygenation according to the 12 layers method shows no significant difference between aliskiren and HCTZ at week 8 before administration of furosemide. However, within group analyses show that aliskiren slightly but not significantly increased oxygenation in the cortex and decreased medullary oxygenation whereas HCTZ induced a significant overall decrease in renal tissue oxygenation. With the same method of analysis we observed that the response to furosemide was unchanged in the HCTZ group at week 8 but was characterized by an increase in both cortical and medullary oxygenation in aliskiren-treated patients. Patients responding to aliskiren and HCTZ by a fall in systolic blood pressure of >10 mmHg improved their renal tissue oxygenation when compared to non-responders. CONCLUSION: With the classical method of evaluation using regions no difference were found between aliskiren and HCTZ on renal tissue oxygenation after 8 weeks. In contrast, with our new method that takes into account the entire kidney, within group analyses show that aliskiren slightly increases cortical and medullary renal tissue oxygenation in hypertensive patients whereas HCTZ decreases significantly renal oxygenation at trough.