Readout architectures for hybrid pixel detector readout chips

The original contribution of this thesis to knowledge are novel digital readout architectures for hybrid pixel readout chips. The thesis presents asynchronous bus-based architecture, a data-node based column architecture and a network-based pixel matrix architecture for data transportation. It is shown that the data-node architecture achieves readout efficiency 99% with half the output rate as a bus-based system. The network-based solution avoids “broken” columns due to some manufacturing errors, and it distributes internal data traffic more evenly across the pixel matrix than column-based architectures. An improvement of > 10% to the efficiency is achieved with uniform and non-uniform hit occupancies. Architectural design has been done using transaction level modeling (TLM) and sequential high-level design techniques for reducing the design and simulation time. It has been possible to simulate tens of column and full chip architectures using the high-level techniques. A decrease of > 10 in run-time is observed using these techniques compared to register transfer level (RTL) design technique. Reduction of 50% for lines-of-code (LoC) for the high-level models compared to the RTL description has been achieved. Two architectures are then demonstrated in two hybrid pixel readout chips. The first chip, Timepix3 has been designed for the Medipix3 collaboration. According to the measurements, it consumes < 1 W/cm^2. It also delivers up to 40 Mhits/s/cm^2 with 10-bit time-over-threshold (ToT) and 18-bit time-of-arrival (ToA) of 1.5625 ns. The chip uses a token-arbitrated, asynchronous two-phase handshake column bus for internal data transfer. It has also been successfully used in a multi-chip particle tracking telescope. The second chip, VeloPix, is a readout chip being designed for the upgrade of Vertex Locator (VELO) of the LHCb experiment at CERN. Based on the simulations, it consumes < 1.5 W/cm^2 while delivering up to 320 Mpackets/s/cm^2, each packet containing up to 8 pixels. VeloPix uses a node-based data fabric for achieving throughput of 13.3 Mpackets/s from the column to the EoC. By combining Monte Carlo physics data with high-level simulations, it has been demonstrated that the architecture meets requirements of the VELO (260 Mpackets/s/cm^2 with efficiency of 99%).

Autotransplantaatio osana purennan hoitoa

Autotransplantaatiota on hyödynnetty hammaslääketieteessä kauan. Se on hyvä hoitomenetelmä puuttuvan hampaan korvaamisessa ja tulisi pitää mielessä vaihtoehtona paljon käytettäville hammasimplanteille. Hampaan menettäminen tai synnynnäinen puutos voi johtaa kasvun myötä purentavirheeseen, jonka hoidossa saatetaan tarvita oikomishoidon lisäksi autotransplantaatiota. Tämän syventävien opintojen kirjallisen työn tarkoituksena on selvittää kirjalisuuden perusteella millaisissa tilanteissa autotransplantaatio soveltuu käytettäväksi purennan hoidossa. Kirjallisuushaku tehtiin PubMed- ja Scopus–tietokannoista. Kirjallisuushaun perusteella autotransplantaatio on erinomainen hoitomenetelmä kasvavien nuorten haasteellisten purentavirheiden hoidossa. Erityisesti menetelmä soveltuu potilaalle, jolla on sekä synnynnäisiä hammaspuutoksia että ahtautta hammaskaarella. Autotransplantaatio on vaativa hoitomenetelmä, joten hoidon suunnittelu ja toteutus vaativat erikoisosaamista. Kirjallisen työn lopuksi esitetään potilastapaus, jossa autotransplantaatiota on käytetty osana purennan hoitoa.

THE ROLE OF CULTURAL AWARENESS IN BUILDING CHINESE HEALTH FOOD BRANDS Using Netnography in Searching Cultural Arguments to Be Used for Marketing Health Foods in China

Despite the complexity of the Chinese culture consumer product businesses should apply them in building brands for Chinese markets. There are reasons to believe that cultural values and attitudes affect the buying behavior of Chinese consumers. Companies that wish to create brands in China should therefore be aware of the prevailing cultural values and consumer attitudes. This thesis will examine which values and attitudes mostly affect Chinese consumers of health food products. The study will be done by conducting a netnography. Because netnography is actually a collection methods rather than a single method, other auxiliary methods will also be applied. These methods are emotion, language and sentiment analysis (ELS analysis). Emotion analysis will be conducted because cultural values are mostly built on emotional basis. Sentiment analysis will assist in recognizing the key factors that help to locate values and attitudes. Because the netnography will be conducted in Chinese web forums by a non-native researcher, linguistic aspects should also be analyzed in parallel with emotions and sentiment analysis. The study shows that the Chinese consumers of health food products put much importance on functional, analytical and collectivistic attitudes as well as social and psychological values. Of all the twelve cultural values defined, the role of family rose above all. Also perseverance, frugality, guanxi and harmony were highly presented. The attitudes were found by recognizing certain attitude factors. Of all the factors, health foods’ functional benefits and aesthetic content together with consumers’ value consciousness surpassed other factors. Besides these results that can be applied by foreign health food companies willing to enter Chinese consumer markets, also academia can benefit this new approach for conducting ethnographies online.

Vascular Healing after Coronary Stenting Evaluated by Optical Coherence Tomography

Optical coherence tomography (OCT) is a novel intracoronary imaging application for the assessment of native lesions and coronary stents. The purpose of this thesis was to evaluate the safety and feasibility of frequency-domain OCT (FD-OCT) based on experiences of the Satakunta Central Hospital (I). Early vascular healing was evaluated after implantation of endothelial progenitor cell capturing (II) and bio-active titanium-nitride-oxide coated stents (III) in two studies, each with 20 patients. Vascular healing was also compared after implantation of bio-active and everolimus-eluting stents on 28 patients after 9-month follow-up (IV). Long-term vascular healing of bio-active and paclitaxel-eluting stents was assessed in the last study with 18 patients (V). The results indicate that FD-OCT is safe and feasible (I). Both bio-active and endothelial progenitor cell capturing stents showed near-complete endothelialisation after one-month follow-up, which is desirable when prolonged dual anti-platelet therapy needs to be avoided after stenting (II and III). Endothelialisation of bio-active stents showed a predictable pattern at mid-term and long-term follow up (IV and V). Endothelialisation of everolimus-eluting stents was not complete at 9 months follow-up, which may suggest that interruption of dual antiplatelet therapy at this time point may not be safe (IV). Finally, delayed vascular healing may be present in patients treated with paclitaxel-eluting stents as long as 4 years from implantation, which reinforces the previously raised concerns on the long-term safety of this device (V).

Pooling järjestely autorahoituksessa

Pro Gradu -tutkielman tavoitteena on luoda uusien autojen kohdevakuudelliseen osamaksukauppaan pooling järjestely, joka mahdollistaisi aiempaa useammalle hakijalle myönteisen luottopäätöksen. Tutkielma tehdään autoliikkeen näkökul-masta. Työn teoriaosuus tutustuu vastaavien järjestelyjen hyödyntämiseen muun muassa vakuutusalalla ja toimitusketjun hallinnassa. Kerättyjen havaintojen avulla muodostetaan viitekehys autokauppaan soveltuvalle järjestelylle. Empiirisessä osuudessa muodostettua pooling järjestelyä testataan yksittäisen rahoitettavan auton case mallin avulla. Lisäksi järjestelyn potentiaalia arvioidaan eri näkökulmista. Saavutettujen tulosten perusteella voidaan todeta, että malli voi olla autoliikkeelle taloudellisesti kannattava ja antaa aihetta jatkotutkimukselle.