Fault detection, diagnosis and active fault tolerant control for a satellite attitude control system

Modern control systems are becoming more and more complex and control algorithms more and more sophisticated. Consequently, Fault Detection and Diagnosis (FDD) and Fault Tolerant Control (FTC) have gained central importance over the past decades, due to the increasing requirements of availability, cost efficiency, reliability and operating safety. This thesis deals with the FDD and FTC problems in a spacecraft Attitude Determination and Control System (ADCS). Firstly, the detailed nonlinear models of the spacecraft attitude dynamics and kinematics are described, along with the dynamic models of the actuators and main external disturbance sources. The considered ADCS is composed of an array of four redundant reaction wheels. A set of sensors provides satellite angular velocity, attitude and flywheel spin rate information. Then, general overviews of the Fault Detection and Isolation (FDI), Fault Estimation (FE) and Fault Tolerant Control (FTC) problems are presented, and the design and implementation of a novel diagnosis system is described. The system consists of a FDI module composed of properly organized model-based residual filters, exploiting the available input and output information for the detection and localization of an occurred fault. A proper fault mapping procedure and the nonlinear geometric approach are exploited to design residual filters explicitly decoupled from the external aerodynamic disturbance and sensitive to specific sets of faults. The subsequent use of suitable adaptive FE algorithms, based on the exploitation of radial basis function neural networks, allows to obtain accurate fault estimations. Finally, this estimation is actively exploited in a FTC scheme to achieve a suitable fault accommodation and guarantee the desired control performances. A standard sliding mode controller is implemented for attitude stabilization and control. Several simulation results are given to highlight the performances of the overall designed system in case of different types of faults affecting the ADCS actuators and sensors.

Running Hot and Cold: Economic Liberalization and Foreign Direct Investment in Latin America by Sector

This article examines the effects of market–oriented economic reforms on foreign direct investment (FDI) flows to Latin America from 1985 to 2006. In contrast with most existing scholarship, we disaggregate FDI into its destination in the primary resource, manufacturing, and service sectors allowing us to determine that different kinds of investments exhibit distinct behavior. Notably, manufacturing FDI appears to be erratic; previous investment is not a predictor of current investment. FDI across sectors is associated with varying policy environments, with service and primary resource investment attracted to hosts with policies associated with more stable economic and political contexts. Overall, manufacturing FDI appears to function more like “hot” portfolio investment and is less likely to provide some of the positive spillover effects thought to be associated with more permanent FDI. These findings have an array of implications for economic, development, and industrial policies throughout Latin America and the developing world.

The Impact of Foreign Direct Investment on Economic Growth

Over the past four decades, the number of democracies in the world has increased exponentially. This project considers how democracy and FDI affect economic growth as well as whether the impact of FDI depends on the level of democracy in a country. Thus, I explore two major research questions: 1) Whether increased FDI speeds up economic growth, controlling for political regime type, urbanization and other developmental indicators; and 2) Whether an increase in political freedom helps or hinders economic growth, and specifically whether the impact of FDI varies depending on the political regime in the recipient country. To examine these questions, this paper used data from 150 countries over a period between 1980 and 2010 and utilized several models, testing variables such as institutions, agglomerations, urbanization, FDI and type of political regime, among others, for their impact on economic growth. I found that FDI does have a positive impact on economic growth, and that this impact is often magnified when it interacts with other relevant factors. I also found that, after controlling for other variables, FDI inflows do not have a different impact on economic growth in autocracies than they do in democracies. This may be partially explained by autocratic outliers such as China and the OPEC states, which have recently experienced rapid export-led growth. This suggests that factors such as education could have a greater impact on a country¿s economic growth than does its political system.

The Redistribution of Property Rights, Corporate Governance and Company Restructuring after Privatisation"

The project covered the main issues of privatisation, corporate governance and company restructuring after privatisation in Hungary and in the Russian Republic, together with a summary of the broader picture of company-level changes in Central and Eastern Europe, discussing the issues of micro-financial restructuring in the Czech Republic, Hungary, Poland and Slovakia. The two countries selected as the focus of research can be regarded as the two most widely differing cases of the economic transformation in Central and Eastern Europe. Hungary began its transition very early in 1989, while Russia was very late in doing so. Hungary first implemented a series of institutional and systemic reforms before stabilising its public finances, while Russia has struggled with financial stabilisation for years without great success. Company restructuring and the introduction of new forms of governance only began in Russia in the mid-1990s. Hungary opted for "traditional" western methods of privatisation and invited a large amount of foreign direct investment (FDI) while in Russia the bulk of state-owned property was privatised either by free distribution or by a strange blend of ESOP-MBO schemes. FDI in Russia remained modest because of the high risk and uncertainty surrounding economic transactions there. Hungary was a forerunner in privatising public utilities, while Russia has moved cautiously in this area. The group's studies show that the Hungarian economy is now over the "transformation recession" and its economic success is largely due to its successful privatisation and to the dominant participation of foreign investors in company take-overs and in the restructuring process. The study of Russia provides a comprehensive account of the main factors in the so-far modest results in Russian privatisation and economic transformation.

In vitro precision of fit of computer-aided designed and computer-aided manufactured titanium screw-retained fixed dental prostheses before and after ceramic veneering

OBJECTIVE To compare the precision of fit of full-arch implant-supported screw-retained computer-aided designed and computer-aided manufactured (CAD/CAM) titanium-fixed dental prostheses (FDP) before and after veneering. The null-hypothesis was that there is no difference in vertical microgap values between pure titanium frameworks and FDPs after porcelain firing. MATERIALS AND METHODS Five CAD/CAM titanium grade IV frameworks for a screw-retained 10-unit implant-supported reconstruction on six implants (FDI tooth positions 15, 13, 11, 21, 23, 25) were fabricated after digitizing the implant platforms and the cuspid-supporting framework resin pattern with a laser scanner (CARES(®) Scan CS2; Institut Straumann AG, Basel, Switzerland). A bonder, an opaquer, three layers of porcelain, and one layer of glaze were applied (Vita Titankeramik) and fired according to the manufacturer's preheating and fire cycle instructions at 400-800°C. The one-screw test (implant 25 screw-retained) was applied before and after veneering of the FDPs to assess the vertical microgap between implant and framework platform with a scanning electron microscope. The mean microgap was calculated from interproximal and buccal values. Statistical comparison was performed with non-parametric tests. RESULTS All vertical microgaps were clinically acceptable with values <90 μm. No statistically significant pairwise difference (P = 0.98) was observed between the relative effects of vertical microgap of unveneered (median 19 μm; 95% CI 13-35 μm) and veneered FDPs (20 μm; 13-31 μm), providing support for the null-hypothesis. Analysis within the groups showed significantly different values between the five implants of the FDPs before (P = 0.044) and after veneering (P = 0.020), while a monotonous trend of increasing values from implant 23 (closest position to screw-retained implant 25) to 15 (most distant implant) could not be observed (P = 0.169, P = 0.270). CONCLUSIONS Full-arch CAD/CAM titanium screw-retained frameworks have a high accuracy. Porcelain firing procedure had no impact on the precision of fit of the final FDPs. All implant microgap measurements of each FDP showed clinically acceptable vertical misfit values before and after veneering. Thus, the results do not only show accurate performance of the milling and firing but show also a reproducible scanning and designing process.

Food Security and Agri-Foreign Direct Investment in Weak States: Finding the Governance Gap to Avoid ‘Land Grab’

Food security is important. A rising world population coupled with climate change creates growing pressure on global world food supplies. States alleviate this pressure domestically by attracting agri-foreign direct investment (agri-FDI). This is a high-risk strategy for weak states: the state may gain valuable foreign currency, technology and debt-free growth; but equally, investors may fail to deliver on their commitments and exploit weak domestic legal infrastructure to ‘grab’ large areas of prime agricultural land, leaving only marginal land for domestic production. A net loss to local food security and to the national economy results. This is problematic because the state must continue to guarantee its citizens’ right to food and property. Agri-FDI needs close regulation to maximise its benefit. This article maps the multilevel system of governance covering agri-FDI. We show how this system creates asymmetric rights in favour of the investor to the detriment of the host state’s food security and how these problems might be alleviated.

Regional Trade Agreements and domestic labour market regulation

This chapter discusses the relationship between labour market regulation and regional trade agreements from both a legal and an economic angle. We examine empirically whether regional trade liberalisation is associated with deterioration (“race to the bottom”) of domestic labour standards beyond those reflected in the 1998 ILO Declaration on the Fundamental Principles and Rights at Work. Using a panel of 90 developed and developing countries, covering the years from 1980 to 2005, we find that after the entry into force of a regional trade agreement (RTA), labour standards applying to employment protection and unemployment benefits are significantly weakened. We show that such a lowering of protection levels tends to occur in high income countries and that this effect mainly stems from RTAs among such countries rather than with low or middle income countries. Concern about competitive pressure to weaken domestic labour regulation is reflected in a variety of undertakings in RTAs not to administer labour laws with a view to improving one’s competitive position in trade or foreign direct investment (FDI). The above-mentioned empirical findings indicate that such provisions could potentially become relevant, and that this is more likely to be the case for high income members of RTAs. Our analysis, from a legal point of view, of relevant institutional and procedural mechanisms indicates however that enforceability of the relevant provisions is weak for most of the existing legal texts.

Precision of fit of implant-supported screw-retained 10-unit computer-aided-designed and computer-aided-manufactured frameworks made from zirconium dioxide and titanium: an in vitro study

OBJECTIVE To analyze the precision of fit of implant-supported screw-retained computer-aided-designed and computer-aided-manufactured (CAD/CAM) zirconium dioxide (ZrO) frameworks. MATERIALS AND METHODS Computer-aided-designed and computer-aided-manufactured ZrO frameworks (NobelProcera) for a screw-retained 10-unit implant-supported reconstruction on six implants (FDI positions 15, 13, 11, 21, 23, 25) were fabricated using a laser (ZrO-L, N = 6) and a mechanical scanner (ZrO-M, N = 5) for digitizing the implant platform and the cuspid-supporting framework resin pattern. Laser-scanned CAD/CAM titanium (TIT-L, N = 6) and cast CoCrW-alloy frameworks (Cast, N = 5) fabricated on the same model and designed similar to the ZrO frameworks were the control. The one-screw test (implant 25 screw-retained) was applied to assess the vertical microgap between implant and framework platform with a scanning electron microscope. The mean microgap was calculated from approximal and buccal values. Statistical comparison was performed with non-parametric tests. RESULTS No statistically significant pairwise difference was observed between the relative effects of vertical microgap between ZrO-L (median 14 μm; 95% CI 10-26 μm), ZrO-M (18 μm; 12-27 μm) and TIT-L (15 μm; 6-18 μm), whereas the values of Cast (236 μm; 181-301 μm) were significantly higher (P < 0.001) than the three CAD/CAM groups. A monotonous trend of increasing values from implant 23 to 15 was observed in all groups (ZrO-L, ZrO-M and Cast P < 0.001, TIT-L P = 0.044). CONCLUSIONS Optical and tactile scanners with CAD/CAM technology allow for the fabrication of highly accurate long-span screw-retained ZrO implant-reconstructions. Titanium frameworks showed the most consistent precision. Fit of the cast alloy frameworks was clinically inacceptable.

The story of Community preference for food security

"Préférence communautaire" is an in-built notion of the CAP since its inception with the Treaty of Rome (1957). Its’ simple objective laid down at the Stresa Conference in 1958 is to prefer community produce over imports wherever possible, while at the same time promoting agricultural exports and FDI (“vocation exportatrice de l’Europe”). Does this contrast or correlate with the notion of “food sovereignty” which originated in 1996 as a notion of small farmer self-sufficiency (Via Campesina), and which now has found its way into the official EC discourse? Recent CAP reforms indeed seem to continue banking on border protection and on the occasional export subsidy. Nonetheless, coming together with claims to mitigate climate change, “food sovereignty” à la CAP fails to acknowledge efficiency losses at home and negative spillover effects on the right to food of food exporting developing countries. This chapter asks whether new non-tariff and domestic support measures are just new wine in the old cask of fortress Europe, together with the FDI promotion instruments of the FED and others. Might the increasing dynamics and new challenges of agricultural trade and investment lead to lower market and production shares for European farms? It concludes that in the medium term the WTO Green Box has the only legal and effective tools to promote EU agriculture and food.

CAD/CAM fabrication accuracy of long- vs. short-span implant-supported FDPs

OBJECTIVE To compare the precision of fit of long-span vs. short-span implant-supported screw-retained fixed dental prostheses (FDPs) made from computer-aided-design/computer-aided-manufactured (CAD/CAM) titanium and veneered with ceramic. The null hypothesis was that there is no difference in the vertical microgap between long-span and short-span FDPs. MATERIALS AND METHODS CAD/CAM titanium frameworks for an implant-supported maxillary FDP on implants with a flat platform were fabricated on one single master cast. Group A consisted of six 10-unit FDPs connected to six implants (FDI positions 15, 13, 11, 21, 23, 25) and group B of six 5-unit FDPs (three implants, FDI positions 21, 23, 25). The CAD/CAM system from Biodenta Swiss AG (Berneck, Switzerland) was used for digitizing (laser scanner) the master cast and anatomical CAD of each framework separately. The frameworks were milled (CAM) from a titanium grade V monobloc and veneered with porcelain. Median vertical distance between implant and FDP platforms from the non-tightened implants (one-screw test on implant 25) was calculated from mesial, buccal, and distal scanning electron microscope measurements. RESULTS All measurements showed values <40 μm. Total median vertical microgaps were 23 μm (range 2-38 μm) for group A and 7 μm (4-24 μm) for group B. The difference between the groups was statistically significant at implant 21 (P = 0.002; 97.5% CI -27.3 to -4.9) and insignificant at implant 23 (P = 0.093; -3.9 to 1.0). CONCLUSIONS CAD/CAM fabrication including laboratory scanning and porcelain firing was highly precise and reproducible for all long- and short-span FDPs. While all FDPs showed clinically acceptable values, the short-span FDPs were statistically more precise at the 5-unit span distance.

The Restructuring in the Post-Crisis Korean Economy

The current paper evaluates the restructuring measures implemented in the post-crisis Korean economy. Its policies taken after the economic crisis were quite successful in terms of economic recovery. The financial and corporate sector reforms undertaken by the Korean government contributed to strengthening the banking and corporate sectors, attracting FDI inflows. However, most indicators show worsening of income inequalities and workers. situation regarding job security. The strengths as well as the weaknesses of the development strategy of Korea and its reform measures undertaken since the occurrence of the economic crisis need to be differentiated.

The Value of Waiting: Foreign Direct Investment with Uncertainty and Imperfect Local Knowledge

This paper examines the role of uncertainty and imperfect local knowledge in foreign direct investment. The main idea comes from the literature on investment under uncertainty, such as Pindyck (1991) and Dixit and Pindyck (1994). We empirically test .the value of waiting. with a dataset on foreign direct investment (FDI). Many factors (e.g., political and economic regulations) as well as uncertainty and the risks due to imperfect local knowledge, determine the attractiveness of FDI. The uncertainty and irreversibility of FDI links the time interval between permission and actual execution of such FDI with explanatory variables, including information on foreign (home) countries and domestic industries. Common factors, such as regulatory change and external shocks, may affect the uncertainty when foreign investors make irreversible FDI decisions. We derive testable hypotheses from models of investment under uncertainty to determine those possible factors that induce delays in FDI, using Korean data over 1962 to 2001.

Foraminiferal abundance, carbonat concentration and dissolution index of sediment core W9903B-51GC

In order to investigate the paleoceanographic record of dissolution of calcium carbonate (CaCO3) in the central equatorial Pacific Ocean, we have studied the relationship between three indices of foraminiferal dissolution and the concentration and accumulation of CaCO3, opal, and Corg in Core WEC8803B-GC51 (1.3°N, 133.6°W; 4410 m). This core spans the past 413 kyr of deposition and moved in and out of the lysoclinal transition zone during glacial-interglacial cycles of CaCO3 production and dissolution. The record of dissolution intensity provided by foraminiferal fragmentation, the proportion of benthic foraminifera, and the foraminiferal dissolution index consistently indicates that the past corrosion of pelagic CaCO3 in the central equatorial Pacific does not vary with the observed sedimentary concentration of CaCO3. Although there is a weak low-frequency variation (~100 kyr) in dissolution intensity, it is unrelated to sedimentary CaCO3 concentration. There are many shorter-lived episodes where high CaCO3 concentration is coincident with poor foraminiferal preservation, and where, conversely, low CaCO3 concentration is coincident with superb foraminiferal preservation. Spectral analyses indicate that dissolution maxima consistently lagged glacial maxima (manifest by the SPECMAP delta18O stack) in the 100-kyr orbital band. Additionally, there is no relationship between dissolution and the accumulation of biogenic opal or Corg or between dissolution and the burial ratio of Corg/CINorg (calculated from Corg and CaCO3). Because previous studies of this core strongly suggest that surface water productivity varied closely with CaCO3 accumulation, both the mechanistic decoupling of carbonate dissolution from CaCO3 concentration (and from biogenic accumulation) and the substantial phase shift between dissolution and global glacial periodicity effectively obscure any simple link between export production, CaCO3 concentration, and dissolution of sedimentary CaCO3.

Disciplining Investment Incentives: A Lost Cause?

An E15 Initiative think piece: Investment incentives rank among the most important policy instruments governments employ to influence the locational decisions of multinational firms. In the wake of the recent increase in locational competition and the growing impact of investment incentives and support measures for state-owned enterprises (SOEs), the need for enhanced disciplines on investment incentives has gained political and academic salience. This think piece explores the evolution of investment incentives from a development and rule-making perspective. It summarises the existing literature and examines current practices and recent trends in FDI flows and the use of various investment incentives. This is followed by a discussion of the reasons for the observed stalemate in attempts at disciplinary rule-making. The paper concludes by putting forth recommendations for data gathering and transparency that could further the move toward improved global governance founded on the increasing complementarities of trade, investment, and competition law and policy as the core pillars of a more open, inclusive, and just world economy.

Industrial Policy in Asia

This paper examines three types of industrialization that have occurred in East Asia: the Japanese, Chinese and generic Asian models. Industrial policies in Japan and the Republic of Korea (ROK) initially protected local companies from foreign investors by imposing high tariffs on foreign investors. But Japan began introducing liberalization policies to attract foreign direct investment (FDI) in the 1960s, and the ROK began to welcome foreign technology in the 1970s. Meanwhile, the governments of the ASEAN countries and Taiwan established export-processing zones (EPZ) to invite FDI by offering preferential treatment, such as tax deductions and exemptions. China adopted similar industrial policies and also established EPZs, attracting the capital and know-how of multinationals and thereby strengthening the international competitiveness of local enterprises. This paper reaches the following three conclusions. First, it would have been difficult for East Asian countries to grow without FDI. Second, central governments were a crucial factor in these countries' growth strategies. Third, EPZs offering preferential treatment can effectively enhance aggregate growth in developing countries, and the Asian experience shows that this strategy can be applied to other countries that satisfy certain preconditions.