[pt] O trabalho conduz uma análise empírica sobre como a credibilidade da política monetária influencia as reações da atividade econômica e da inflação a um aumento da taxa de juros. Como parte da metodologia, um índice de credibilidade foi construído a partir do desvio da expectativa de inflação com relação à meta para o período. Esse índice foi empregado em um modelo T-VAR junto a séries de hiato do produto, núcleo da inflação, taxa de câmbio e taxa de juros para gerar funções resposta ao impulso generalizadas através das quais foi possível comparar a dinâmica entre os regimes com credibilidade e sem credibilidade. As principais conclusões foram que a presença de credibilidade reduz o custo do aumento aos juros e intensifica a redução da inflação a um aumento da taxa de juros. / [en] The work conducts an empirical assessment on how monetary policy credibility influences the reaction of output and inflation to an increase in interest rate. As part of the methodology, a credibility index was built based on the deviation of the expected inflation from its target for a given period. This index was employed in a T-VAR model – also containing series of output gap, inflation core, exchange rate and interest rate – in order to generate generalized impulse response functions through which the dynamics of the with- and without- credibility regimes could be compared. The main conclusions were that the presence of credibility lowers the cost of raising interest rates and strengthens the inflation reduction in response to an interest rate increase.

The main focus of this thesis is to analyse signals (signal-dependent analysis) and room responses (system-dependent analysis) from a statistical point of view, attempt to determine the underlying statistical relationships between the reverberant signals and the room responses and propose relevant statistical models. Based on such a statistical framework, this thesis aims to propose novel methodologies for the extraction of room acoustical information and parameters from reverberant signals. Schroeder's theory is experimentally evaluated for various Room Transfer Functions (RTFs) measured in many source/receiver positions in various enclosures and several related aspects are discussed. Using a statistical approach, the effects of reverberant energy on the histograms and statistical measures are discussed and models describing the relationship of statistical measures between the reverberant signal and the RTFs are extracted. Then, the statistical properties of Binaural Room Transfer Functions (BRTFs) and binaural cues are examined. The well-known property of the spectral standard deviation of the magnitude of RTFs, that is its convergence to 5.6 dB for diffuse fields, is examined for the case of BRTFs, using a similar approach and a generic model for the relationship of the spectral standard deviation of RTFs and BRTFs. This thesis is also concerned with the distance estimation problem from a perceptual and computational point of view. Two novel methods for the estimation of the source/receiver distance using speech signals are proposed. The first method is able to detect the distance between the speaker and the microphone in a room environment using single-channel signals. The distance-dependent variation of several temporal and spectral statistical features of single-channel signals is studied and a novel sound source distance detector, based on these features is developed. The second method estimates distance from binaural speech signals (two-channel signals). This method does not require a priori knowledge of the room impulse response, the reverberation time or any other acoustical parameter and relies on a set of novel features extracted from the reverberant binaural signals. For this method, a novel distance estimation feature is introduced exploiting the standard deviation of the difference of the magnitude spectra of the left and right binaural signals (termed here as Binaural Spectral Magnitude Difference Standard Deviation (BSMD STD)). Moreover, an extended and novel set of additional features based on the statistical properties of binaural cues (ILDs, ITDs, ICs) is extracted from an auditory front-end which models the peripheral processing of the human auditory system. Both methods rely on novel distance-dependent features, related to statistical parameters of speech signals. Finally, a novel method for the estimation of the direct-to-reverberant-ratio (DRR) from dual-channel microphone recordings without having knowledge of the source signal is presented. / Η παρούσα διατριβή ασχολείται με τη μελέτη και ανάλυση των στατιστικών χαρακτηριστικών ηχητικών σημάτων και των ακουστικών αποκρίσεων χώρου, έχοντας ως πρωταρχικό σκοπό να προτείνει σχέσεις που περιγράφουν τη συσχέτιση των στατιστικών χαρακτηριστικών των σημάτων με αντήχηση με τις ακουστικές αποκρίσεις χώρων. Βάσει ενός τέτοιου θεωρητικού πλαισίου, η διατριβή αυτή αποσκοπεί στο να προτείνει νέες μεθοδολογίες για την εξαγωγή πληροφορίας που σχετίζεται με τα ακουστικά χαρακτηριστικά των χώρων, κάνοντας χρήση ηχογραφημένων ηχητικών σημάτων (π.χ. σήματα ομιλίας) στους εκάστοτε κλειστούς χώρους. Το θεωρητικό υπόβαθρο αυτής της διατριβής βασίζεται σε υπάρχοντα θεωρητικά μοντέλα για το ηχητικό πεδίο μέσα σε ένα κλειστό χώρο, όπως, για παράδειγμα, το στατιστικό μοντέλο του Schroeder. Το μοντέλο του Schroeder επιβεβαιώνεται πειραματικά για ακουστικές αποκρίσεις που έχουν μετρηθεί σε διάφορες θέσεις, μέσα σε κλειστούς χώρους, οι οποίοι διαφέρουν στα ακουστικά χαρακτηριστικά τους. Βάσει στατιστικής ανάλυσης, εξάγονται στατιστικά μοντέλα, τα οποία περιγράφουν την επίδραση της αντήχησης στα ηχητικά σήματα, όταν αυτά αναπαραχθούν μέσα σε ένα κλειστό χώρο. Στη συνέχεια, λαμβάνοντας υπόψη αντιληπτικά μοντέλα ακοής, τα οποία προϋποθέτουν την ύπαρξη δυο ηχητικών σημάτων (δυο αυτιά, αμφιωτική ακοή) σε αυτή τη διατριβή, μελετώνται κάποιες παράμετροι οι οποίες εξάγονται από αμφιωτικές ακουστικές αποκρίσεις χώρου. Η ιδιότητα της φασματικής τυπικής απόκλισης συναρτήσεων μεταφοράς χώρων να συγκλίνει στην τιμή των 5.6~dB για διάχυτα ηχητικά πεδία, επεκτείνεται στην περίπτωση των αμφιωτικών αποκρίσεων χώρου και προτείνεται ένα γενικευμένο μοντέλο που συσχετίζει τη φασματική τυπική απόκλιση μονοφωνικών και αμφιωτικών συναρτήσεων μεταφοράς χώρου. Η διατριβή αυτή, επίσης, ασχολείται με το πρόβλημα της εκτίμησης της απόστασης μεταξύ πηγής και δέκτη. Προτείνονται δυο νέες μέθοδοι για την εκτίμηση της απόστασης μεταξύ πηγής και δέκτη, κάνοντας χρήση ηχητικών σημάτων ομιλίας. Η προτεινόμενη μέθοδος βασίζεται σε μια σειρά από στατιστικές παραμέτρους των οποίων οι τιμές μεταβάλλονται είτε στο πεδίο του χρόνου είτε στο πεδίο της συχνότητας. Η δεύτερη προτεινόμενη μέθοδος αφορά, επίσης, στην εκτίμηση της απόστασης πηγής/δέκτη, αλλά από αμφιωτικά σήματα. Η μέθοδος αυτή δεν προαπαιτεί γνώση της ακουστικής απόκρισης του χώρου, του χρόνου αντήχησης ή άλλης ακουστικής παραμέτρου και βασίζεται σε μια σειρά από νέες παραμέτρους, οι οποίες μπορούν να υπολογισθούν από τα αμφιωτικά σήματα με αντήχηση. Οι παράμετροι συνδυάζονται με δυο διαφορετικές τεχνικές αναγνώρισης προτύπων των οποίων τα μειονεκτήματα και πλεονεκτήματα συζητώνται. Στα πλαίσια αυτής της μεθόδου, προτείνεται μια νέα παράμετρος, η οποία βασίζεται στη διαφορά της φασματικής τυπικής απόκλισης του αριστερού και του δεξιού αμφιωτικού ηχητικού σήματος, η οποία αποδεικνύεται ότι σχετίζεται με τα στατιστικά της αντίστοιχης μονοφωνικής ακουστικής απόκρισης. Τέλος, προτείνεται μια σειρά από παραμέτρους οι οποίες βασίζονται στα στατιστικά χαρακτηριστικά αμφιωτικών παραμέτρων και σχετίζονται με το αντιληπτικό μοντέλο της ανθρώπινης ακοής. Τέλος, προτείνεται μια νέα μέθοδος για την εκτίμηση της στάθμης λόγου κατευθείαν προς ανακλώμενου ήχου από στερεοφωνικά σήματα.

The interconnection of molecular machines with different functionalities to form molecular communication systems can increase the number of design possibilities and overcome the limited reliability of the individual molecular machines. Artificial information exchange using molecular signals would also expand the capabilities of single engineered cell populations by providing them a way to cooperate across heterogeneous cell populations for the applications of synthetic biology and lab-on-a-chip systems. The realization of molecular communication systems necessitates analysis and design of the communication channel, where the information carrying molecular signal is transported from the transmitter to the receiver. In this thesis, significant progress towards the use of microfluidic channels to interconnect molecular transmitter and receiver pairs is presented. System-theoretic analysis of the microfluidic channels are performed, and a finite-impulse response filter is designed using microfluidic channels. The spectral density of the propagation noise is studied and the additive white Gaussian noise channel model is developed. Memory due to inter-diffusion of the transmitted molecular signals is also modeled. Furthermore, the interference modeling is performed for multiple transmitters and its impact on the communication capacity is shown. Finally, the efficient sampling of the signal transduction by engineered bacterial receivers connected to a microfluidic channel is investigated for the detection of the pulse-amplitude modulated molecular signals. This work lays the foundation for molecular communication over microfluidic channels that will enable interconnection of engineered molecular machines.

This article investigates the interrelations between the initial members of the Euro area and five important Central and Eastern European economies. We set up a theoretical open economy model to derive the Purchasing Power Parity, the Interest Rate Parity, the Fisher Inflation Parity, and an output gap relation. After taking convergence into account, they are used as restrictions on the cointegration space of a structural vector error correction model. We then employ generalized impulse response analysis to assess the dynamic effects of shocks in output and interest rates on the respective other area as well as the implications of shocks in the exchange rate and in relative prices on both areas. The results show a high degree of interconnectedness between the two economies. There are strong positive spillovers in output to the respective other region with the magnitude of the impact being similarly strong in both areas. Furthermore, we find a multiplier effect being present in Eastern Europe and some evidence for the European Central Banks' desire towards price stability. (author's abstract) / Series: Department of Economics Working Paper Series

This thesis studies bubbles in the U.S. stock market and how they are influenced by monetary policy pursued by the FED. Using Kalman filtering, the log-real price of S&P 500 is decomposed into a market-fundamentals component and a bubble component. The market-fundamentals component depends on the expected future dividends and the required rate of return, while the bubble component is treated as an unobserved state vector in the state-space model. The results suggest that, mainly in recent decades, the bubble has accounted for a substantial portion of S&P 500 price dynamics and might have played a significant role during major bull and bear markets. The innovation of this thesis is that it goes one step further and investigates the effects of monetary policy on both estimated components of S&P 500. For this purpose, the block- restriction VAR model is employed. The findings indicate that the decreasing interest rates have a significant short-term positive effect on the market-fundamentals component but not on the bubble. On the other hand, quantitative easing seems to have a positive effect on the bubble but not on the market-fundamentals component. Finally, the results suggest that the FED has not been successful at distinguishing between stock price movements due to fundamentals or the price misalignment.

Perfusion magnetic resonance imaging is modern diagnostic method used mainly in oncology. In this method, contrast agent is injected to the subject and then is continuously monitored the progress of its concentration in the affected area in time. Correct determination of the arterial input function (AIF) is very important for perfusion analysis. One possibility is to model AIF by multichannel blind deconvolution but the estimated AIF is necessary to be scaled. This master´s thesis is focused on description of scaling methods and their influence on perfussion parameters in dependence on used model of AIF in different tissues.

Made available in DSpace on 2017-07-10T17:11:44Z (GMT). No. of bitstreams: 1 DISSERTACAO OSCAR SCUSSEL.pdf: 4301786 bytes, checksum: 8a64e99e73bc5e4478b9e5077d78baed (MD5) Previous issue date: 2013-03-04 / Impulse Response Functions (IRFs) are important in many engineering applications, mainly in structural dynamics and modal analysis involving experimental modal tests. These IRFs can be identified through several methods. Among these, the classical covariance method is one of the most used and it is based on the sum of convolution from the correlation functions between input and output signals known. However, this method is limited because it employs a large number of samples and has drawbacks related to over parametrization. In this sense, this work presentes and review the covariance method expanded in the ortonormal basis Kautz functions, because this alternative way allows to avoid these drawbacks. In order to ilustrate the procedure an algorithm with multiple objective functions to obtain the optimal poles of the Kautz filter is shown. The results are provided through three degree-of-freedom mechanical system simulated and experimental data in a beam to show the advantages, drawbacks, simplicity and efficiency of the proposed approach. / As funções de resposta ao impulso (IRFs) exercem papel de destaque na identificação de sistemas reais quando têm-se o conhecimento dos dados de entrada/saída do sistema. Essas IRFs são relevantes em muitas aplicações de Engenharia, especialmente em análise modal experimental de estruturas. Dentre os métodos para obtenção dessas IRFs, destaca-se o clássico método das covariâncias baseado na soma de convolução das funções de correlação entre os sinais de entrada e saída conhecidos. No entanto, esse método é limitado quando são coletadas muitas amostras e possui algumas desvantagens como efeitos de sobreparametrização. Neste sentido, este trabalho apresenta e revisa o método das covariâncias expandido na base ortonormal de Kautz para aplicações em identificação de sistemas mecânicos, pois essa forma alternativa permite evitar esses efeitos de sobreparametrização. Para obter os pólos ótimos dos filtros de Kautz, emprega-se um algoritmo multi-objetivo. Os resultados são verificados através de um sistema mecânico com três graus de liberdade e em dados experimentais a partir de uma viga na condição livre-livre no qual verificam-se as vantagens, desvantagens, simplicidade e eficiência do método proposto.

由於住宅價格變動毫無預警制度，人民往往憑著個人主觀的判斷而決定何時購屋或售屋，而此種主觀判斷住宅市場利多及利空的觀念，對住宅市場的供需會產生失衡現象，因此是否可從經濟面的訊息找到住宅價格變動的答案，使住宅價格在尚未變動前，政府即已掌握資訊，提前做好穩定住宅價格的因應對策，使民眾依其需要而購屋，則是本研究之主要目的。 　　本研究從文獻中整理出影響住宅價格變動的七個總體經濟變數，這些總體經濟變數包含工資、物價、所得、貨幣供給額、股價、匯率及利率等，並利用向量自我迴歸模式(VAR)進行實證，以便較客觀的獲得變數間的落後期數及暸解變數間雙向、單向及領先、同步、落後情形，且進一步探討住宅價格與每一個總體經濟變數間影響程度大小及影響情形，以釐清各變數之間的關係。 　　本研究利用VAR模型進行住宅價格與總體經濟變數關係的研究，經由實證，得到下列的結論： 　　一、實證結果方面 　　本研究之實證主要有因果關係檢定與分析、變異數分解之分析及衝擊反應之分析三方面，其實證結果如下所述。 　　（一）因果關係檢定與分析 　　由因果關係檢定與分析中，得到股價、物價、匯率、貨幣供給額及利率均能做為住宅價格變動的領先指標。 　　（二）變異數分解之分析 　　由住宅價格之變異數分解中，得知住宅價格自身的解釋程度僅占三分之一，另三分之二被其他的總體經濟變數所解釋，顯示住宅價格受總體經濟變數的影響相當大；而從其他總體經濟變數之變異數分解中，得知住宅價格變動會干擾到總體經濟變數，而使總體經濟變數受干擾而變動變動。 　　（三）衝擊反應之分析 　　從總體經濟變數對住宅價格的衝擊反應分析圖中可以明顯看出除工資外，其餘總體經濟變數變動對住宅價格造成的衝擊均相當明顯，但匯率及利率對住宅價格的衝擊是負向的。 　　住宅價格對所得、股價、匯率及利率的衝擊相當明顯，而其對匯率的衝擊是負向。 　　二、政策應用方面 政府的決策過程中常會有時間落後的現象，而本研究實證的目的則是要使政府能事先掌握住宅價格的變動，並提前做好穩定住宅價格的因應對策，減少政府決策過程的時間落後現象，而實證結果應用至政策方面的內容則由以下說明之。 　　（一）藉由因果關係檢定與分析的實證內容，可以縮短政府對住宅價格不合理變動問題認定落後的時間。 　　（二）從變異數分解之分析的實證內容中，可以使決策者在解決住宅價格問題時，將行動落後的時間減少。 　　（三）由衝擊反應之分析中，可以使政府在執行穩定住宅價格政策時，將衝擊落後的時間縮小。 / Since there is no alarm system in the change of housing prices, people often decide when to buy or when to sell based on personal and subjective judgement. Such concept to judge subjectively whether the housing market is bull or bear will cause unequilibrium in the supply and demend of the housing market. There it is possible to find out the answers to the change of housing prices from economic side so that the government can have enough information and can be prepared in the reaction to stabilizing the housing prices, and so that the public can buy house according to their needs is the main purpose of this project. 　　Seven variables in macroeconomics influencing the change of housing prices have been taken from reative literature, including wage, commodity price, income, money supply, stock price, exchange rate, and interest rate. VAR has been employed to verify so that the more objective lagging period among variable can be known, and the bi-directional, uni-directional, leading, contemporaneous, and lagging situation among variables can be understood. Furthermore, the degree and the status of influence of each macroeconomic variable to the housing price will be investigated to clarify the relations among the variables. 　　The present project investigate the relations between housing price and macroeconomic variables. We have the following findings: 　　I、In Empirical Study: 　　The empirical study in this project includes causal relation test and analysis, the analysis of variable decompositon, and the analysis of impact response. The results are shown in the following: 　　(I) Causality Test and Analysis 　　In the causality test and analysis, we find out that stock price, commodity price, exchange rate, money supply and interest rate all can be the leading indicators in the change of housing prices. 　　(II) The Analysis of Variable Decomposition 　　It is learned from the variable decomposition of housing prices that housing price can only explain one third of the cause in its change, the other two thirds are explained by other macroeconomic variables. It shows that housing prices are subject to the influence of macroeconomic variables greatly. 　　From the variable decomposition of other macroeconomic variables, we know that the change in housing prices will affect macroeconomic variables so that the macroeconomic variables will change. 　　(III) The Analysis of Impact Response 　　It can be obviously seen from the analysis figure of the impact response of the macroeconomics to housing prices, all macroeconomic variables will cause obvious impact to housing prices expect for wage. However, both exchange rate and interest rate have negative impact to housing prices. 　　Housing prices' impact to income, stock prices, exchange rate and interest rate is quite obvious, among which, the impact to exchange rate is negative. 　　II、Policy Application 　　It is a common phenomenon that there often will be lagging in time in government's decision making. The purise of the empirical study in this project is to let the government to know in advance the change of housing prices and to let the government to know in advance the change of housing prices and to let the government be prepared in the reaction of stabilizing the housing prices to minimize the lagging in the decision making process. The contents of application of the empirical study to policy are explained in the following: 　　(I) With the empirical results of the change of the causality test and analysis, the time for the government to recognize the unreasonable changes in housing prices can be shortened. 　　(II) With the empirical results of the analysis of variable decomposition, the decision makers' lagging in the action responding to housing pricescan be minimized. 　　(III) With the analysis in impact response, the lagging in impact will be minimized when the government executing her housing price stabilizing policy.

本篇主要為原物料指數與總體經濟物價間動態關聯性的研究。由於近年來糧食價格高漲，本研究選取CRB現貨指數（Commodity Research Bureau）、CCI期貨指數（Continuous Commodity Index），與CRB農產品指數為原物料指數以觀察原物料價格對總體面物價影響的程度；研究期間為2001年10月至2011年3月；總經物價指標選擇生產者物價指數（PPI）、消費者物價指數（CPI）、再加上國內生產毛額（GDP）；選取的國家為美國、臺灣與中國。本研究以Johansen共整合、向量自我迴歸模型、向量誤差修正模型、Granger因果關係檢定及衝擊反應分析等方法，探討三項原物料指數與總體經濟指標的互動關係。 研究結果顯示，原物料指數與總體指標之間的長期均衡關係不明顯。因果檢定顯示，CCI指數在因果檢定上領先CRB指數與CRB農產品指數；除了美國的GDP之外，CCI指數也領先各項總體經濟指標，但不論是CRB現貨指數或CRB農產品指數，對總經物價指標的領先-落後關係都不明顯，表示在CCI指數為較佳的預測指標。由衝擊反應分析的結果顯示，除了有共整合關係的變數間相互影響為長期性之外，受影響的物價指標僅在短期內會受到原物料價格變動的影響：總體物價指標面對原物料價格波動的反應約3期之後反應便逐漸消失，顯示原物料價格與總體物價指數之間的短期失衡期間並不長。 / This paper investigates the relationship between the commodity indexes and macroeconomic price indexes. Due to the sharp increase of food price in recent years, we add CRB index (Commodity Research Bureau), CCI index (Continuous Commodity Index), and CRB foodstuffs index in the research to see the magnitude of commodity price indexes to macroeconomic price indexes. This paper selects United State, Taiwan and China as samples and manages to find out the relationship of commodity indexes and macroeconomic price indexes by applying monthly data from October 2001 to March 2011. Macroeconomic price indexes are PPI (Producer Price Index), CPI( Consumer Price Index) and plus GDP Index. This paper tries to get the answer by applying Johansen Cointegration Test, Vector Autoregression Model(VAR), Vector Error Correction Model (VECM), Granger causality test and Impulse Response Analysis. The result does not show obvious long-term relationship between commodity price indexes and macroeconomic price indexes; and Granger causality test exhibits that CCI index takes the lead in the change of time. But we do not get consistent result between CRB index, CRB foodstuffs index and macroeconomic price indexes in Granger causality test which means commodity spot indexes do not necessarily lead in the change of time. This result implies that CCI index a better indicator in forecasting. According to Impulse Response Analysis, macroeconomic price indexes are influenced by commodity index only in a short period of time and this result tells us that the disequilibrium between commodity indexes and macroeconomic price indexes will not last long.

The retina is a highly metabolically active tissue with large demands on the supply of nutrients. Disorders affecting the retina often include some vasculopathy with an impact on retinal circulation. Studies of retinal haemodynamics could thus help to detect, differentiate and diagnose diseases, to monitor changes in disease as well as progression and efficiency of the therapy. The present studies were an attempt to validate and determine the clinical usefulness of a newly developed technique for studying the retinal circulation in human eyes. We used different techniques to evaluate different parameters of retinal circulation. We examined how leukocyte velocity determined with Blue Field Simulation and transit times, mean transite time (MTT) and arterio-venous passage (AVP), and vessel diameter, determined from fluorescein angiograms, together reflects the retinal circulation. MTT was determined with a method based on an Impulse-Response technique, MTTIR. In a study on monkeys we compared our method, together with two conventional methods, with an absolute measurement of retinal blood flow (RBF) determined with labelled microspheres. There was a weak, but not statistically significant, correlation between retinal blood flow and MTTIR (r2 = -0.60, p = 0.06), but no useful correlation between retinal blood flow and either of the other two measures of transit times. In a study on healthy eyes we determined the effect of a physiological provocation, changes in arterial blood gases, on retinal circulation. Breathing pure oxygen or increased level of carbon dioxide in inspired air had no effect on MTT, but oxygen reduced leukocyte velocity and vessel diameter and carbon dioxide increased leukocyte velocity significantly. We concluded that unchanged transit time trough the retinal tissue was not due to a lack of effect of the gas provocation but a result due to concomitant changes in volume and flow. In a study on eyes of patients with diabetic retinopathy we investigated the relation between the extent of retinal circulation changes and the severity of the diabetes retinopathy (DRP). Transit times were relatively unaffected until proliferative DRP (PDRP) developed. In eyes with PDRP both MTTIR and AVP were increased. After panretinal photocoagulation treatment MTTIR returned to normal levels and vessel diameters tended to decrease while leukocyte velocity and AVP remained unchanged. We concluded that the increase in MTTIR in eyes with PDRP is at least partly explained by vessel dilation, causing an increased volume of the retinal vascular bed.