Moderate inflation and the deflation-depression link

In a recent paper, Atkeson and Kehoe (2004) demonstrated the lack of a robust empirical relationship between inflation and growth for a cross-section of countries with 19th and 20th century data, concluding that the historical evidence only provides weak support for the contention that deflation episodes are harmful to economic growth. In this paper, we revisit this relationship by allowing for inflation and growth to have a nonlinear specification dependent on inflation levels. In particular, we allow for the possibility that high inflation is negatively correlated with growth, while a positive relationship exists over the range of negative-to-moderate inflation. Our results confirm a positive relationship between inflation and growth at moderate inflation levels, and support the contention that the relationship between inflation and growth is non-linear over the entire sample range.Inflation (Finance)

Avoiding Liquidity Traps

Once the zero bound on nominal interest rates is taken into account, Taylor-type interest-rate feedback rules give rise to unintended self-fulfilling decelerating inflation paths and aggregate fluctuations driven by arbitrary revisions in expectations. These undesirable equilibria exhibit the essential features of liquidity traps, as monetary policy is ineffective in bringing about the government's goals regarding the stability of output and prices. This paper proposes several fiscal and monetary policies that preserve the appealing features of Taylor rules, such as local uniqueness of equilibrium near the inflation target, and at the same time rule out the deflationary expectations that can lead an economy into a liquidity trap.TAYLOR RULES; LIQUIDITY TRAPS; ZERO BOUND ON NOMINAL INTEREST RATES.

Monetary Policy and Multiple Equilibria

In this paper, we characterize conditions under which interest rate feedback rules wherby the nominal interest rate is set as an increasing function of the inflation rate generate multiple equilibria. We show that these conditions depend not only on the fiscal regime (as emphasized in the fiscal theory of the price level) but also on the way in which money is assumed to enter preferences and technology. We analyze this issue in flexible and sticky price environments.MONETARY POLICY ; PRICES ; INTEREST RATE

Reestablishing the income-democracy nexus

A number of recent empirical studies have cast doubt on the "modernization theory" of democratization, which posits that increases in income are conducive to increases in democracy levels. This doubt stems mainly from the fact that while a strong positive correlation exists between income and democracy levels, the relationship disappears when one controls for country fixed effects. This raises the possibility that the correlation in the data reflects a third causal characteristic, such as institutional quality. In this paper, we reexamine the robustness of the income-democracy relationship. We extend the research on this topic in two dimensions: first, we make use of newer income data, which allows for the construction of larger samples with more within-country observations. Second, we concentrate on panel estimation methods that explicitly allow for the fact that the primary measures of democracy are censored with substantial mass at the boundaries, or binary censored variables. Our results show that when one uses both the new income data available and a properly non linear estimator, a statistically significant positive income-democracy relationship is robust to the inclusion of country fixed effects.Income

Performance improvement of shunt active power filter based on indirect control with a new robust phase-locked loop

Introduction. Since the development of the first active power filter (APF) in 1976, many efforts have been focused on improving the performances of the APF control as the number of different nonlinear loads has continued to increase. These nonlinear loads have led to the generation of different types of current harmonics, which requires more advanced controls, including robustness, to get an admissible total harmonic distortion (THD) in the power system. Purpose. The purpose of this paper is to develop a robust phase-locked loop (PLL) based on particle swarm optimization-reference signal tracking (PSO-RST) controller for a three phase three wires shunt active power filter control. Methodology. A robust PLL based on PSO-RST controller insert into the indirect d-q control of a shunt active power filter was developed. Results. Simulation results performed under the MATLAB/SimPowerSystem environment show a higher filtering quality and a better robustness compared to the classical d-q controls. Originality. Conventional PLLs have difficulty determining the phase angle of the utility voltage sources when grid voltage is distorted. If this phase angle is incorrectly determined, this leads to a malfunction of the complete control of the active power filters. This implies a bad compensation of the current harmonics generated by the nonlinear loads. To solve this problem we propose a robust and simple PLL based on PSO-RST controller to eliminate the influence of the voltage harmonics. Practical value. The proposed solution can be used to improve the functioning of the shunt active power filter and to reduce the amount of memory implementation.Вступ. З моменту розробки першого фільтра активної потужності (ФАП) у 1976 р. багато зусиль було спрямовано на покращення характеристик управління ФАП, оскільки кількість різних нелінійних навантажень продовжувала зростати. Ці нелінійні навантаження призвели до генерації різних типів гармонік струму, що потребує більш досконалих засобів управління, у тому числі стійких, для отримання допустимого повного гармонічного спотворення (THD) в енергосистемі. Мета. Метою даної статті є розробка надійного контуру фазового автопідстроювання частоти (ФАПЧ) на основі контролера відстеження еталонного сигналу оптимізації рою частинок (ВЕС ОРЧ) для трифазного трипровідного шунтуючого фільтра активної потужності. Методологія. Розроблено надійну систему ФАПЧ на основі контролера ВЕС ОРЧ, вбудованого в непрямий d-q контроль шунтуючого фільтра активної потужності. Результати. Результати моделювання, виконаного в середовищі MATLAB/SimPowerSystem, демонструють високу якість фільтрації та більшу надійність у порівнянні з класичним d-q керуванням. Оригінальність. Звичайні ФАПЧ мають труднощі з визначенням фазового кута джерел напруги, коли напруга мережі спотворена. Неправильне визначення цього фазового кута призводить до порушення повного керування фільтрами активної потужності. Це означає погану компенсацію гармонік струму, створюваних нелінійними навантаженнями. Для вирішення цієї проблеми ми пропонуємо стійкий та простий ФАПЧ на основі контролера ВЕС ОРЧ для усунення впливу гармонік напруги. Практична цінність. Запропоноване рішення може бути використане для поліпшення роботи шунтуючого фільтра активної потужності і зменшення обсягу потрібної пам'яті.

Three energy scales in the superconducting state of hole-doped cuprates detected by electronic Raman scattering

We explored by electronic Raman scattering the superconducting state of Bi-2212 single crystal by performing a fine tuned doping study. We found three distinct energy scales in A1g, B1g and B2g symmetries which show three distinct doping dependencies. Above p=0.22 the three energies merge, below p=0.12, the A1g scale is no more detectable while the B1g and B2g scales become constant in energy. In between, the A1g and B1g scales increase monotonically with under-doping while the B2g one exhibits a maximum at p=0.16. The three superconducting energy scales appear to be an universal feature of hole-doped cuprates. We propose that the non trivial doping dependence of the three scales originates from Fermi surface topology changes and reveals competing orders inside the superconducting dome.Comment: 6 pages, 5 figure

Reestablishing the Income-Democracy Nexus

A number of recent empirical studies have cast doubt on the “modernization theory” of democratization, which posits that increases in income are conducive to increases in democracy levels. This doubt stems mainly from the fact that while a strong positive correlation exists between income and democracy levels, the relationship disappears when one controls for country fixed effects. This raises the possibility that the correlation in the data reflects a third causal characteristic, such as institutional quality. In this paper, we reexamine the robustness of the income-democracy relationship. We extend the research on this topic in two dimensions: first, we make use of newer income data, which allows for the construction of larger samples with more within-country observations. Second, we concentrate on panel estimation methods that explicitly allow for the fact that the primary measures of democracy are censored with substantial mass at the boundaries, or binary censored variables. Our results show that when one uses both the new income data available and a properly non linear estimator, a statistically significant positive income-democracy relationship is robust to the inclusion of country fixed effects.