Cross-Layer Resiliency Modeling and Optimization: A Device to Circuit Approach

The never ending demand for higher performance and lower power consumption pushes the VLSI industry to further scale the technology down. However, further downscaling of technology at nano-scale leads to major challenges. Reduced reliability is one of them, arising from multiple sources e.g. runtime variations, process variation, and transient errors. The objective of this thesis is to tackle unreliability with a cross layer approach from device up to circuit level

The evolution of systems-integration capability in latecomer contexts: the case ofIran’s thermal and hydro power generation systems

This study concerns building capabilities within the electricity sector of Iran, a developing country. It focuses on two areas of high-technology development,• hydro electricity generation plants and thermal electricity generation plants, and investigates the accumulation of local capabilities to undertake large and complex development projects in these two areas. The empirical aim of the thesis is to analyse how far the local capabilities have advanced and what can be done to enhance them. The business of engineering and developing complex electricity generation systems, such as hydro and thermal power plants, is an example of high-value high-technology capital goods industries (sometimes referred to as CoPS in the innovation studies literature). This literature suggests that systems integration is a core capability of leading suppliers in CoPS industries. Most studies of capability building at the firm level in latecomer contexts, however, have focused on mass-manufacturing firms rather than on project-based ones. The CoPS literature, on the other hand, has investigated the concept of systems integration capability within the context of developed economies. Therefore, this research aims to examine latecomer systems integration capability (LSIC) in these two CoPS areas in Iran to develop our understanding of the nature and evolution of LSIC. This research is carried out as an exploratory case study, combining some elements of latecomer theory, systems integration and capability theory to develop the analytical framework for the study. The framework is then applied to evidence gathered from two major Iranian systems integrators that lead engineering and development activities involved in the construction of power plants. Evidence is gathered on the evolution of micro-level attributes, including people, knowledge, processes and structures, underlying LSIC, along with changes in products and outcomes of systems integration activities. These categories of evidence are combined with the evidence on the internal context of the firms and their external environment to reveal their achievements in the accumulation of LSIC, and to understand the dynamics behind the evolution of LSIC. The analysis of this thesis shows how the two Iranian firms entered into the business of systems integration of power plant systems, and have gradually built higher levels of LSIC, allowing them to succeed in competitive local and overseas markets, and to diversify into local markets for other complex projects. Nevertheless, there have been imbalances, spurts of rapid capability growth, periods of falling behind in specific areas of LSIC, close connections and relationships (amounting to a co-evolution among LSIC areas), and major investments and strategies to remedy imbalances, and to sustain the firms' progress. This thesis also attempts to explain these complex variations in the evolutionary paths of LSIC. In addition to contributing to the latecomer capability literature, this research suggests some policy and business strategy implications.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Improving physico-chemical properties and antifouling of nanofiltration membranes using coating DLC nanostructures

In this study for the first time, polymeric nanofiltration membranes based on polyethersulfone (PES) polymer were surface-modified by using a diamond-like carbon (DLC) nanostructure coating layer. The effect of this coating on the performance and anti-fouling properties of the membrane was investigated. The surface-modified membranes significantly improved the salt separation and their hydrophilicity was more than the control membrane after the reformation process. The amount of salt separation increased from 64% to 98% due to the decrease in the size of the holes on the surface. The absorption characteristic of DLC nanostructure in contact with feed solution was reported as another reason in this field. The contact angle (CA) of water also decreased due to the improvement of hydrophilicity, which means the increase of hydrophilicity in the above membranes. The amount of pure water flux passing through the membranes increases from one side of the membrane surface to both sides with the increase significantly of the coating level, so that its value reaches from about 8L/m2h for the M0 membrane to 65L/m2h in the membrane containing M3. The surface morphology of unmodified membranes changed from a rough state with an average of 16nm in PES membranes to a smoother state in modified membranes with an average of 9nm. The recovery rate of the flux and the total absorption rate were obtained in complete agreement with the results obtained from the CA of water and the amount of the calculated surface roughness parameter. The increase in the flux recovery rate and the decrease in the fouling rate indicated the successful improvement of the antifouling properties as a result of the coating process. Based on the washing test, the prepared sample has good stability against the number of washing cycles, which is a very important advantage for practical applications

Induced pluripotent stem cell-derived hepatocyte-like cells : The lipid status in differentiation, functionality, and de-differentiation of hepatic cells

Ihmisen maksasta eristettyjä soluja (PHH) pidetään ns. ”kultaisena standardina” maksan fysiologian, toksisuuden ja lipidien homeostaasin tutkimiseksi. Nämä solut ovat vaikeasti saatavia sekä toiminnoiltaan heterogeenisiä ja viljeltynä menettävät maksalle spesifit toiminnot suhteellisen nopeasti jo muutamassa päivässä. Uudelleen ohjelmoiduista kantasoluista (iPS-solut) tuotetut maksasolujen kaltaiset solut (HLC) tarjoavat vaihtoehtoisen mallin maksan normaalin ja poikkeavan rasvaaineenvaihdunnan tutkimiseksi. Näiden kantasoluista tuotettujen maksasolujen etuna on rajoittamaton saatavuus sekä mahdollisuus tuottaa niitä eri geenitaustan omaavien yksilöiden soluista. Koska rasva-aineenvaihdunnan häiriöillä on keskeinen rooli monien yleisten tautien kuten ei-alkoholiperäisen rasvamaksan sekä ateroskleroottisen sydän- ja verisuonitaudin patogeneesissä, kantasoluista tuotetut maksasolut tarjoavat uuden potilasspesifisen keinon rasva-aineenvaihdunnan ja sen häiriöiden perusmekanismien tutkimiseksi. Lisäksi tätä solumallia on mahdollista hyödyntää lääkekehityksessä ja erityisesti lääkkeiden aiheuttaman maksatoksisuuden tutkimisessa. Jotta näitä maksasoluja voidaan hyödyntää maksimaalisesti, on tärkeää selvittää niiden yksityiskohtainen lipidiprofiili ja verrata sitä ihmisen maksasta eristettyihin soluihin. Rasvat ovat merkittävä molekyyliluokka, ja niillä on tärkeä tehtävä solun rakenteessa, toiminnassa ja signaloinnissa. On myös osoitettu, että tietyt rasvahapot edistävät hermo- ja rasvasolujen erilaistumista. Siksi maksasolujen lipidi- ja rasvahappoprofiilien muutoksien syvällinen tuntemus sekä erilaistumisen (differentiaation) että spesifisten ominaisuuksien vähenemisen (dedifferentiaation) aikana auttaisi meitä tuottamaan kantasoluista kypsiä maksasoluja, joiden lipidiprofiili muistuttaisi maksasta eristettyjen solujen lipidiprofiilia entistä paremmin. Lisäksi tämän tiedon avulla viljely-ympäristö voitaisiin optimoida solujen tarpeiden mukaiseksi ja sen seurauksena pidentää niiden elinkaarta ja funktionaalisuutta. Tämän väitöskirjatyön päätavoitteina oli ensin tutkia lipidi- ja rasvahappoprofiilien muutoksia maksasolujen erilaistumisen aikana ja pyrkiä tunnistamaan tässä erilaistumisessa ja kypsymisessä tärkeitä lipidejä. Tätä tarkoitusta varten tehtiin yksityiskohtainen lipidomiikka-analyysi ja rasva-aineenvaihduntaan osallistuvien avaingeenien ilmentymisen profilointi useina eri ajankohtina erilaistumisprosessin aikana. Toinen tavoite oli kuvata kattavasti kantasoluista tuotettujen maksasolujen lipidi- ja rasvahappoprofiili ja verrata sitä tämänhetkisiin standardimaksasolumalleihin. Maksasolujen tuottamiseen iPS-soluista käytettiin viittä eri menetelmää ja näiden maksasolujen lipidiprofiili samoin kuin niiden kyky syntetisoida ja prosessoida rasvahappoja tutkittiin perusteellisesti ja verrattiin laajasti käytettyihin maksasolumalleihin. Lisäksi tarkasteltiin kunkin menetelmän avulla tuotettujen erilaisten kasvatusolosuhteiden vaikutusta solujen ilmiasuun sekä toiminnallisuuteen. Kolmas tavoite keskittyi maksasolujen dedifferentiaation, eli soluviljelmissä tapahtuvan maksasoluominaisuuksien menettämisen, taustalla olevien mekanismien tutkimiseen seuraamalla ihmisen maksasta eristettyjen solujen lipidiprofiilin muutoksia soluviljelyn aikana. Lipidomiikka-analyysista saatuja tuloksia täydennettiin mikroRNA-analyysillä, jotta voitiin tunnistaa eri tavoin ilmentyneet mikroRNA:t, jotka voisivat säädellä tuota prosessia. Yhteenvetona voidaan todeta, että iPS-soluista tuotetut maksasolut tarjoavat asianmukaisen ja toimivan solumallin ihmisen rasva-aineenvaihdunnan tutkimiseksi sekä solu- että molekyylitasolla. Lisäksi tämä tutkimus tarjoaa uusia havaintoja lipidien, rasvahappojen ja mikroRNA:n mahdollisesta roolista differentiaatio- ja/tai dedifferentiaatioprosessissa, joita voidaan soveltaa kantasoluista tuotettujen maksasolujen kypsymistä parantavien viljely-ympäristöjen suunnittelussa. Koska maksasolut menettävät soluviljelmissä merkittäviä metabolisia toimintojaan suhteellisen nopeasti, tämä tutkimus tarjoaa uusia ideoita ja strategioita kasvatusjärjestelmien parantamiseksi maksasolujen pitämiseksi toiminnallisina pitkäaikaisissakin soluviljelmissä.Primary human hepatocytes (PHHs) are currently considered the “gold standard” cell model for investigating the liver physiology, toxicity, and lipid homeostasis. However, PHHs are scarce and functionally heterogeneous, and when cultured, they lose their liver-specific functions relatively fast within a few days. Induced pluripotent stem cell-derived hepatocyte-like cells (iPSC-HLCs) provide a relevant alternative model for PHHs to study the lipid derangements of the liver. Unlike PHHs, the cell source to generate iPSC-HLCs is unlimited and they can be advantageously generated from selected individuals with different genetic backgrounds. Since lipid defects play central roles in the pathogenesis of several common diseases such as non-alcoholic fatty liver disease and atherosclerotic cardiovascular disease, iPSC-HLCs could serve as a novel platform for studying the basic mechanisms of the lipid metabolism and its dysregulation in a truly patientspecific manner. Additionally, this cell model could be utilised in drug discovery and especially in studying the drug induced hepatotoxicity. To maximise the utilisation of HLCs for such valuable purpose, it is critical to characterise their detailed lipid profile in relation to the human adult liver cells. Lipids are a major class of molecules, which play critical roles in cellular structure, function, and signalling. It has been shown that certain fatty acids (FAs) promote neuronal and adipocyte differentiation. Therefore, in-depth knowledge of changes in lipid and FA profile of the hepatocytes during differentiation and dedifferentiation could assist us to generate matured target cells, which resemble the lipid profile of PHHs even closer. In addition, this knowledge can be utilised to optimise the culture environment according to the cellular need and subsequently prolong the life span and functionality of both the iPSC-HLCs and the PHHs in Culture. Major aims of this thesis were to first study the alterations in the lipid and FA profile of the cells during the hepatic differentiation in order to identify the lipid species that may play important roles in the differentiation and maturation of hepatocytes. For this purpose, detailed lipidomic analysis and gene expression profiling of a set of key genes involved in the metabolism of lipids were performed at several time points during the entire differentiation process from iPSC to HLCs. The second aim was to comprehensively characterise the lipid and FA profile of HLCs against current standard hepatic cell models. HLCs were generated by five different methods and their lipid profile as well as their ability to synthesise, elongate, and desaturate FAs were thoroughly assessed and compared to the profiles of widely used hepatocyte models, PHHs and HepG2 cells. In addition, the effect of various conditions or stimuli introduced by each method were evaluated on HLCs’ phenotype and functionality. The third aim focussed on the mechanisms behind the hepatic de-differentiation by studying the alterations in the lipid profile of the PHHs during their prolonged two-dimensional (2D) culture. In addition, we complemented our results from lipidomics with miRNA analysis to further identify the differentially expressed miRNAs that may regulate changes in the lipid profile of PHHs during the process of de-differentiation. Taken together, our findings illustrate that HLCs differentiated from iPSCs provide a relevant and functional cell model to explore human lipid homeostasis at both cellular and molecular levels. Additionally, this thesis provides novel findings on the possible role of lipids, FAs, and miRNAs in the process of differentiation and/or de-differentiation and may be applied in designing culture environments that would improve the maturity of HLCs. Since hepatocytes in 2D culture lose their metabolic competence and viability relatively fast, this thesis offers some new ideas and strategies to improve the culture systems for maintaining hepatocytes in longterm culture

Evaluation of the Effect of Rewarding Managers on the Capital Structure and Financial Performance of Companies Listed on Tehran Stock Exchange

Object and purpose of the study: The aim of this study was to evaluate the effect of rewarding managers on the capital structure and financial performance of the companies listed on Tehran Stock Exchange in the time period of 2005-2012. Methods: Data of 58 companies and research hypotheses were tested using panel data and ordinary least squares of regression model. Findings: Based on the results of the study, factors such as size of the company and the changes in cash and ratio of market value to book value of equity have significant negative impact on the capital structure of the company, the other conclusion is that there is a significant positive relationship between board bonus and financial performance and parameters such as the size of the company. Conclusion: Rewarding managers causes to increase their efforts and thus increment of productivity and improvement of company performance. Keywords: Rewarding managers, Capital structure, Financial performance, JEL Classification.

Connecting the dots in infrastructure development and management: The Africa agenda for new innovation

It is widely accepted that the growth and prosperity of nations is dependent on economic infrastructure. Infrastructure is constituted by cyber-physical systems that enable communications (e.g. postal, telephone and internet) as well as transportation (e.g. road, water, air), energy (e.g. electricity and gas) and other utilities (e.g. drinking water and waste) (Chandler, 1977; NAO, 2013). It provides the basis for economic growth and prosperity through the provision of essential services that enable economic and social activity. As a result, it delivers significant benefits, both directly through the services it delivers, and indirectly through the impact of those services on the rest of the economy (Nightingale et al 2016). However, these benefits come at a cost. Infrastructure is expensive to build, operate and maintain. The provision of infrastructure involves degradation and the consumption of natural ecosystems, displacement of local communities, CO_{2} emissions, noise and pollution. Infrastructure is typically long-lived and the costs of poor choices and mistakes can affect future generations. This is especially prominent with politically motivated infrastructure investment decisions, which have a lifespan that coincides with electoral cycles. To complicate matters further, the costs and benefits of infrastructure provision fall unequally across society in a way that benefits a minority (usually local to the area of infrastructure development) although the distribution of costs are more widely spread (for example in investments funded by taxes) (ibid). In this context, infrastructure investment decisions are not only complex they are inherently political