VictorJuiz/thesis huggingface dataset:
Information, Central Bank Communication, and Aggregate Fluctuations

This thesis examines two closely related issues: (1) the ability of imperfect information models to explain some aspects of business cycle dynamics, and (2) the interaction between central bank communications and monetary policy. These issues are related because central bank communications can only be studied in models with imperfect information. In chapter 1, I investigate the ability of a noisy rational expectations model to generate plausible macroeconomic dynamics. The model allows for imperfect, heterogeneous information, and signal extraction from endogenous variables. I find that imperfect information significantly improves the model's ability to generate persistent, hump-shaped responses to a transitory monetary policy shock. This is achieved without the need for mechanical frictions. In addition, the model generates realistic inflation forecast errors. Chapter 2 explores the relationship between central bank statements about future policy and the degree of commitment. I allow the central bank to make (possibly vague) statements about its expected future policy. I begin by assuming that the central bank adopts a loss function which internalizes the bygone costs of deviating from such a pre-announced policy action. The resulting policy is a convex combination of pure discretion and full commitment. As the precision of central bank statements increases, this policy converges to the full commitment policy. I then show that this type of commitment to internalize bygone costs is sustainable only for moderate degrees of precision. Chapter 3 studies the impact of central bank communications about the state of the economy. In particular, I examine the extent to which increased central bank transparency creates a meaningful trade-off between beneficially conveying fundamental information and adversely contaminating observed data with the central bank's opinion. This question is addressed in a variant of the model from chapter 1. In this environment, both the central bank and private agents learn about the state of the economy from observations of endogenous variables. By making the central bank learn from endogenous variables, I am able to study the impact of communications precision on the bank's signal extraction problem.

Keywords: Macroeconomics
Imperfect Information
Central Bank Communication
Monetary Policy
Advisor: Alexopoulos, Michelle
Essays on Monetary Coordination, Exchange Rate Volatility and Interfirm Networks

This dissertation consists of three independent essays in Macroeconomics. The first essay analyzes monetary coordination between currency areas. It is shown that search frictions can generate the deviations from the law of one price and that each country is tempted to exploit these deviations by inflation. Monetary coordination eliminates the inefficiency caused by inflation. The welfare gains from coordination increase when the two economies become more integrated. In contrast to traditional models, the need for coordination exists even after each country is allowed to directly tax foreign holdings of its currency. The second essay studies the behavior of exchange rates in an environment with search frictions. In contrast to traditional models, even without any nominal rigidity, the model can generate enough volatility of exchange rates found in the data. The changes in the behavior of exchange rates under different regimes are also examined in this essay. The model shows a sharp increase in the volatility of exchange rates when moving from a pegged to a floating exchange regime, while there is no such systematic change in fluctuations of output or consumption. Moreover, the co-movements of output and consumption across countries are higher under a fixed rate regime than under a flexible rate regime. These results are consistent with empirical findings. The final essay focuses on the competition between groups of allied firms. In the essay we propose a model of group fitness and develop an approach to evaluate the fitness of groups and the utility of their member firms. A group has high fitness if member firms have four features: (i) high capacity, (ii) being embedded in dense relationships, (iii) holding complementary resources and (iv) having limited competition and conflict. We illustrate the effectiveness of our model and methodology by applying it to the airline groups between 1997 and 2002. By examining what really happened to the airline groups afterwards, we found that the predictions based on the comparison between the fitness scores of actual groups formed and those of the corresponding population constructed are reasonably accurate, and that the implications based on the ranking of individual firm utility within each group are generally supported.

Keywords: Monetary Coordination
Exchange Rate Volatility
Interfirm Networks
Advisor: Shi, Shouyong
Essays on the Political Economy of the Centralized Provision of Local Public Goods

This thesis explores the political economy aspects of the provision of local public goods by higher levels of government. Chapter 1 focuses on local public goods as instruments for special interest politics at the supra-local level, with an emphasis on public infrastructure. To capture the implications of long-run relationships between political parties and their loyal supporters, I set out a dynamic probabilistic voting model which predicts that the geographic pattern of spending depends on the way the government balances long-run `machine politics' considerations with the more immediate concern to win over swing voters. To assess the empirical relevance of both forces, I analyse rich data on road spending from a panel of electoral districts in Québec. Empirical results exploiting the province's linguistic fragmentation provide robust evidence that partisan loyalty is a key driver of the geographic allocation of spending. Chapter 2 proposes a theoretical framework to analyse the coexistence of multiple tiers of government in local public good provision. I study the effects of such partial decentralization on accountability using a two-period political agency model, in which two levels of government are involved in public good provision and voters are imperfectly informed about each government's contribution to the public good. The model predicts that the net effect of a departure from complete centralization (or decentralization) balances the benefits of vertical complementarity against the loss of accountability following from imperfect information and detrimental vertical interactions. Chapter 3 investigates the impact of partial decentralization on local electoral accountability in the context of California's school finance system. I exploit the peculiarities California's school finance system and the federal No Child Left Behind Act of 2001 to estimate the extent to which politicians are punished or rewarded for observed policy outcomes, and how this channel is affected by the degree of centralization. Results show that voters are responsive to differences in dropout rates and pupil-teacher ratios, and that incumbents are less likely to be reelected when a district's degree of centralization is high. Increased federal involvement after 2001 is associated with sharper local electoral accountability.

Keywords: local public goods
political economy
fiscal federalism
distributive politics
school finance
accountability
No Child Left Behind
infrastructure spending
Quebec
California
Advisor: McMillan, Robert
Multilinear Subspace Learning for Face and Gait Recognition

Face and gait recognition problems are challenging due to largely varying appearances, highly complex pattern distributions, and insufficient training samples. This dissertation focuses on multilinear subspace learning for face and gait recognition, where low-dimensional representations are learned directly from tensorial face or gait objects. This research introduces a unifying multilinear subspace learning framework for systematic treatment of the multilinear subspace learning problem. Three multilinear projections are categorized according to the input-output space mapping as: vector-to-vector projection, tensor-to-tensor projection, and tensor-to-vector projection. Techniques for subspace learning from tensorial data are then proposed and analyzed. Multilinear principal component analysis (MPCA) seeks a tensor-to-tensor projection that maximizes the variation captured in the projected space, and it is further combined with linear discriminant analysis and boosting for better recognition performance. Uncorrelated MPCA (UMPCA) solves for a tensor-to-vector projection that maximizes the captured variation in the projected space while enforcing the zero-correlation constraint. Uncorrelated multilinear discriminant analysis (UMLDA) aims to produce uncorrelated features through a tensor-to-vector projection that maximizes a ratio of the between-class scatter over the within-class scatter defined in the projected space. Regularization and aggregation are incorporated in the UMLDA solution for enhanced performance. Experimental studies and comparative evaluations are presented and analyzed on the PIE and FERET face databases, and the USF gait database. The results indicate that the MPCA-based solution has achieved the best overall performance in various learning scenarios, the UMLDA-based solution has produced the most stable and competitive results with the same parameter setting, and the UMPCA algorithm is effective in unsupervised learning in low-dimensional subspace. Besides advancing the state-of-the-art of multilinear subspace learning for face and gait recognition, this dissertation also has potential impact in both the development of new multilinear subspace learning algorithms and other applications involving tensor objects.

Keywords: Subspace Learning
Multilinear
Tensor
Face Recognition
Gait Recognition
Biometrics
Dimensionality Reduction
Embedding
Feature Extraction
Advisor: Plataniotis, Konstantinos N.
Venetsanopoulos, Anastasios N.
Sensitive Solution-processed Quantum Dot Photodetectors

Optical sensing for imaging applications has traditionally been enabled by single-crystalline photodetectors. This approach has dramatically curtailed monolithic integration of a variety of optically-sensitive materials onto silicon read-out circuits. The advent of solution-processed optoelectronic materials such as colloidal quantum dots offers the potential of a revolution in optoelectronics. Their solution-processibility enables low-cost monolithic integration with an arbitrary substrate. This dissertation presents the first high-sensitivity solution-processed photodetectors. It does so by leveraging the high degree of control offered by nanoscale materials engineering. Material processing routes are developed to achieve sufficient carrier mobility and sensitization that lead to high photoconductive gain up to 10^3 A/W, observed for the first time in soft materials. A method to remove charge-transport-inhibiting moieties from the nanocrystal surface is developed. Surface treatment procedures are then advanced to prolong the carrier lifetime and thus sensitize the material. The sequence of these processing stages is crucial for the noise performance of the device. Processing conditions that lead to high photoconductive gain and low noise current are then reported to achieve highly sensitive photodetectors with reported D* on the order 10^13 Jones. The spectral tunability offered by colloidal quantum dots enables monolithic multispectral photodetectors. The material challenges, imposed by the behaviour of matter in the nanoscale, are addressed to report sensitive photodetectors in the visible and infrared parts of spectrum. Carrier lifetime determines the temporal response of a photoconductor. The abundance of trap states on the nanocrystal surface and their associated carrier lifetimes mandate careful attention in order to preserve the trap states that yield temporal response acceptable for imaging applications. It is shown for the first time that the temporal response of a quantum dot photoconductor can be tailored by careful control over surface chemistry. Materials species were identified as responsible for particular photocurrent temporal components. These findings are then exploited to isolate and remove surface species responsible for undesirably long time constants. A solution-processed photoconductive detector is reported that exhibits high sensitivity (D* ~10^12 Jones) and temporal response of 25 ms, suitable for imaging applications.

Keywords: Photodetectors
Quantum Dots
Advisor: Sargent, Edward H.
Infrared Sensitive Solution-processed Quantum Dot Photovoltaics in a Nanoporous Architecture

If solar energy is to be a significant component of our energy supply, technologies are required which produce high efficiency solar cells using inexpensive materials and versatile manufacturing processes. Solution-processed materials have been used to create low cost, easily fabricated devices, but have suffered from low power conversion efficiencies. A lack of infrared energy capture limits their efficiency. In this work we develop solution-processed photovoltaic devices using lead sulphide quantum dots and high surface area porous oxide electrodes. The resultant devices have a spectral response from 400 to 1800 nm. In fabricating these devices we utilize crosslinking molecules. We explore the impact crosslinkers have on the mobility and morphology of quantum dot films using field effect transistors and transmission electron microscopy. We also explore a hybrid organic/inorganic route for controlling the net doping in quantum dot films. We investigate the chemical and compositional changes that lead sulphide quantum dots films undergo during crosslinker treatment and annealing. Using this information we optimize our charge separation efficiency and our open circuit voltage. The resulting devices have an infrared power conversion efficiency of 2%, four orders of magnitude higher than that in previously reported lead sulphide quantum dot devices.

Keywords: photovoltaic
quantum dot
infrared
PbS
nanoporous
Advisor: Sargent, Edward H.
Physical Synthesis Toolkit for Area and Power Optimization on FPGAs

A Field-Programmable Gate Array (FPGA) is a configurable platform for implementing a variety of logic circuits. It implements a circuit by the means of logic elements, usually Lookup Tables, connected by a programmable routing network. To utilize an FPGA effectively Computer Aided Design (CAD) tools have been developed. These tools implement circuits by using a traditional CAD flow, where the circuit is analyzed, synthesized, technology mapped, and finally placed and routed on the FPGA fabric. This flow, while generally effective, can produce sub-optimal results because once a stage of the flow is completed it is not revisited. This problem is addressed by an enhanced flow known Physical Synthesis, which consists of a set of iterations of the traditional flow with one key difference: the result of each iteration directly affects the result of the following iteration. An optimization can therefore be evaluated and then adjusted as needed in the following iterations, resulting in an overall better implementation. This CAD flow is challenging to work with because for a given FPGA researchers require access to each stage of the flow in an iterative fashion. This is particularly challenging when targeting modern commercial FPGAs, which are far more complex than a simple Lookup Table and Flip-Flop model generally used by the academic community. This dissertation describes a unified framework, called the Physical Synthesis Toolkit (PST), for research and development of optimizations for modern FPGA devices. PST provides access to modern FPGA devices and CAD tool flow to facilitate research. At the same time the amount of effort required to adapt the framework to a new FPGA device is kept to a minimum. To demonstrate that PST is an effective research platform, this dissertation describes optimization and modeling techniques that were implemented inside of it. The optimizations include: an area reduction technique for XOR-based logic circuits implemented on a 4-LUT based FPGA (25.3% area reduction), and a dynamic power reduction technique that reduces glitches in a circuit implemented on an Altera Stratix II FPGA (7% dynamic power reduction). The modeling technique is a novel toggle rate estimation approach based on the XOR-based decomposition, which reduces the estimate error by 37% as compared to the latest release of the Altera Quartus II CAD tool.

Keywords: Area and Power Optimization Algorithms
Physical Synthesis
Power Modeling
Field-Programmable Gate Arrays
Advisor: Brown, Stephen
Colloidal Quantum Dot Schottky Barrier Photodetectors

Herein, we report the first solution-processed broadband photodetectors to break the past compromise between sensitivity and speed of response. Specifically, we report photodiodes having normalized detectivity (D*) > 1012 Jones and a 3dB bandwidth of > 2.9 MHz. This finding represents a 170,000 fold improvement in response speed over the most sensitive colloidal quantum dot (CQD) photodetector reported1 and a 100,000 fold improvement in sensitivity over the fastest CQD photodetector reported2. At the outset of this study, sensitive, solution-processed IR photodetectors were severely limited by low response speeds1. Much faster response speeds had been demonstrated by solution-processed photodetectors operating in the visible3, but these devices offered no benefits for extending the spectral sensitivity of silicon. No available solution-processed photodetector combined high sensitivity, high operating speed, and response to illumination across the UV, visible and IR. We developed a fast, sensitive, solution-processed photodetector based on a photodiode formed by a Schottky barrier to a CQD film. Previous attempts to form sensitive photodetectors based on CQD photodiodes had demonstrated low quantum efficiencies that limited sensitivity4,5. Efficient, sensitive semiconductor photodiodes are based on two fundamental characteristics: a large built-in potential that separates photogenerated charge carriers and minimizes internal noise generation, and high semiconductor conductivity for efficient collection of photogenerated charge. Schottky barriers to CQD films were developed to provide high, uniform built-in potentials. A multi-step CQD ligand exchange procedure was developed to allow deposition of tightly packed films of CQDs with high mobility and sufficiently well-passivated surfaces to form high-quality metallurgical junctions. The temporal response of the CQD photodiodes showed separate drift and diffusion components. Combined with detailed measurements of the Schottky barrier, these characteristics provided the physical basis for a numerical model of device operation. Based on this understanding, devices that excluded the slow diffusive component were fabricated, exploiting only the sub-microsecond field-driven transient to achieve MHz response bandwidth. These devices are the first to combine megahertz-bandwidth, high sensitivity, and spectral-tunability in photodetectors based on semiconducting CQDs. Record performance is achieved through advances in materials and device architecture based on a detailed understanding the physical mechanisms underlying the operation of CQD photodiodes.

Keywords: nanotechnology
Schottky barrier
nanocrystal
colloidal quantum dot
solution processed semiconductor
optoelectronic
photovoltaic
photodetector
Advisor: Sargent, Edward H.
Wireless Communication over Fading Channels with Imperfect Channel Estimates

In wireless communication systems, transmitted signals are corrupted by fading as well as noise. The receiver can benefit from the estimates of fading channels to detect the transmitted symbols. However, in practical wireless systems channel information cannot be estimated perfectly at the receiver. Therefore, it is crucial to examine the effect of channel estimation error on the structure and performance of the receivers. In the first part of the thesis, we study single-user systems with single-antenna reception over fading channels in the presence of Gaussian-distributed channel estimation error. By using the statistical information of the channel estimation error, we will derive the structure of maximum-likelihood receivers for a number of different modulation formats and then analyze their performance over fading channels. In the second part of the thesis, we consider the uplink of multi-user wireless systems with multi-antenna reception. For conventional diversity combining techniques such as maximal ratio combining and optimum combining we analyze the performance degradation due to imperfect channel estimates in the presence of multiple interfering users for several fading channels. By investigating the probability density function of the output signal-to-interference ratio, we will derive analytical expressions for several performance measures such as the average signal-to-interference ratio, outage probability and average bit-error probability. These expressions quantify performance degradation due to channel estimation error.

Keywords: Wireless communication
Fading channels
Diversity combining
Channel estimation error
Advisor: Lim, Teng Joon
Cultural Expressions of Tokugawa Japan and Chosŏn Korea: an Analysis of the Korean Embassies in the Eighteenth Century

This doctoral thesis presents a historical study of the diplomatic exchanges between the Japanese and the Korean embassy in the eighteenth century. Neighbourly relationships (J: kōrin, K: kyorin) were maintained between Tokugawa Japan (1603-1868) and Chosŏn Korea (1392-1910) for more than 250 years. The visitations of the Korean embassy, dispatched to congratulate a new Tokugawa shogun, were often seen as the symbol of their amicable and friendly relationship, and it is well known that the Koreans were cordially welcomed by the Tokugawa bakufu. Despite these neighbourly relations, the visitations of the embassy had a more pragmatic purpose. More complex political conditions and nature were immanent within and between the both states. In the diplomatic interaction, the officials in the two states had traditional and obstinately-held perceptions towards the counterpart hidden behind the pleasant gesture. In this thesis, I attempt to uncover what is associated with these neighbourly relations, by revealing the cultural awareness and consciousness of these two states in East Asia through detailed examinations of the historical sources. To find the notions behind the exchange, my thesis illustrates Japanese and Korean hua-yi awareness that came to light through the interactions between the Japanese and the Koreans. The Chinese hua-yi order, the concept of looking at the Chinese dynasties as the center, was said to dominate the East Asian order. From the Chinese point of view, Tokugawa Japan and Chosŏn Korea were barbaric and on the margins, but from the perspectives of the two countries, they certainly recognized themselves as the centers. On the basis of the dynamism of historical events, thoughts, and notions between Tokugawa Japan and Chosŏn Korea in the eighteenth century, this research will examine multi-layered perspectives of the individual Japanese and Koreans who played essential roles in diplomacy. How were those officials representing the two states aware of their peers, and how did these notions affect the modern history of the two countries? This question is consistently engaged in this thesis, and to answer it the research will be further explored.

Keywords: Japan-Korea relations
the 18th century
Advisor: Schmid, Andre