A telemetry antenna system for unmanned air vehicles

This paper presents a low VSWR high gain telemetry antenna system manufactured for UAVs that provides 360± coverage in the roll plane of the UAV. Proposed telemetry antenna system includes four telemetry antennas, one power divider that has one input and four output terminals which feeds the telemetry antennas with equal magnitude and phase. Proposed high gain telemetry antennas are based on the feeding of the microstrip patch antenna via aperture coupling. Full coverage in the roll plane of the UAV is obtained by using circular array configuration of telemetry antennas. RF power divider is designed by using couple of Wilkinson power dividers with equal line lengths and impedance sections from input terminal to the all four output terminals

Labor Market Institutions and Wage and Inflation Dynamics

This paper developes a New Keynesian (NK) model that incorporates standard search and matching structure with firing costs. I analyze how labor market institutions affect the macroeconomic dynamics, in particular, wage and inflation dynamics. I particularly look at two important labor market institutions namely unemployment benefits and firing costs. I find that in countries where unemployment benefits are higher and there are more strict employment protection legislations, inflation and wages become less volatile and more persistent. I also find that the level of these labor market institutions affect how wages and inflation respond to exogenous shocks, in particular, to productivity and monetary policy shocks. I first present some empirical evidence that shows a cross-country link between labor market institutions and wages and inflation. Then I build a dynamic stochastic general equilibrium model which provides theoretical support for this empirical evidence.balance of payments; disequilibrium; exchange rates

An Empirical Investigation of Labor Income Processes

Labor Income Risk, Profile Heterogeneity, Random Walk Model, Incomplete Markets, Idiosyncratic Shocks

Learning Your Earning: Are Labor Income Shocks Really Very Persistent?

The current literature offers two views on the nature of the income process. According to the first view, which we call the “restricted income profiles” (RIP) model (MaCurdy, 1982), individuals are subject to large and very persistent shocks, while facing similar life-cycle income profiles (conditional on a few characteristics). According to the alternative view, which we call the “heterogeneous income profiles” (HIP) model (Lillard and Weiss, 1979), individuals are subject to income shocks with modest persistence, while facing individual-specific income profiles. While labor income data does not seem to distinguish between the two hypotheses in a definitive way, the RIP model is overwhelmingly used to specify the income process in economic models, because it delivers implications consistent with certain features of consumption data. In this paper we study the consumption-savings behavior under the HIP model, which so far has not been investigated. In a life-cycle model, we assume that individuals enter the labor market with a prior belief about their individual-specific profile and learn over time in a Bayesian fashion. We find that learning is slow, and thus initial uncertainty affects decisions throughout the life-cycle allowing us to estimate the prior uncertainty from consumption behavior later in life. This procedure implies that 40 percent of variation in income growth rates is forecastable by individuals at time zero. The resulting model is consistent with several features of consumption data including (i) the substantial rise in within-cohort consumption inequality (Deaton and Paxson 1994), (ii) the non-concave shape of the age-inequality profile (which the RIP model is not consistent with), and (iii) the fact that consumption profiles are steeper for higher educated individuals (Carroll and Summers 1991). These results bring new evidence from consumption data on the nature of labor income risk.Labor income risk, Incomplete markets, Inequality, Consumption-savings decision, Kalman filter.

An empirical investigation of labor income processes

In this paper we reassess the evidence on labor income risk. There are two leading views on the nature of the income process in the current literature. The first view, which we call the "Restricted Income Profiles" RIP process, holds that individuals are subject to large and very persistent shocks, while facing similar life-cycle income profiles. The alternative view, which we call the "Heterogeneous Income Profiles" HIP process, holds that individuals are subject to income shocks with modest persistence, while facing individual-specific income profiles. We first show that ignoring profile heterogeneity, when in fact it is present, introduces an upward bias into the estimates of persistence. Second, we estimate a parsimonious parameterization of the HIP process that is suitable for calibrating economic models. The estimated persistence is about 0.8 in the HIP process compared to about 0.99 in the RIP process. Moreover, the heterogeneity in income profiles is estimated to be substantial, explaining between 56 to 75 percent of income inequality at age 55. We also find that profile heterogeneity is substantially larger among higher educated individuals. Third, we discuss the source of identification - in other words, the aspects of labor income data that allow one to distinguish between the HIP and RIP processes. Finally, we show that the main evidence against profile heterogeneity in the existing literature - that the autocorrelations of income changes are small and negative - is also replicated by the HIP process, suggesting that this evidence may have been misinterpreted.

Do Stockholders Share Risk More Effectively Than Non- stockholders?

This paper analyzes the extent of risk-sharing among stockholders and among nonstockholders. Wealthy households play a crucial role in many economic problems due to the substantial concentration of asset holdings in the U.S. data. Hence, to evaluate the empirical importance of market incompleteness, it is essential to determine if idiosyncratic shocks are important for the wealthy, who have access to better insurance opportunities, but also face different risks, than the average household. We study a model where each period households decide whether to participate in the stock market by paying a fixed cost. Due to this endogenous entry decision, the testable implications of perfect risk- sharing take the form of a sample selection model, which we estimate and test using a semi-parametric GMM estimator proposed by Kyriazidou (2001). Using data from PSID we strongly reject perfect risk-sharing among stockholders, but perhaps surprisingly, do not find evidence against it among non-stockholders. These results appear to be robust to several extensions we considered. These findings indicate that market incompleteness may be more important for the wealthy, and suggest further focus on risk factors that primarily affect this group, such as entrepreneurial income risk.Perfect risk-sharing, incomplete markets, semiparametric estimation, Generalized Method of Moments, limited stock market participation.

A parsimonious macroeconomic model for asset pricing

I study asset prices in a two-agent macroeconomic model with two key features: limited stock market participation and heterogeneity in the elasticity of intertemporal substitution in consumption (EIS). The model is consistent with some prominent features of asset prices, such as a high equity premium; relatively smooth interest rates; procyclical stock prices; and countercyclical variation in the equity premium, its volatility, and in the Sharpe ratio. In this model, the risk-free asset market plays a central role by allowing non-stockholders (with low EIS) to smooth the fluctuations in their labor income. This process concentrates non-stockholders' labor income risk among a small group of stockholders, who then demand a high premium for bearing the aggregate equity risk. Furthermore, this mechanism is consistent with the very small share of aggregate wealth held by non-stockholders in the US data, which has proved problematic for previous models with limited participation. I show that this large wealth inequality is also important for the model's ability to generate a countercyclical equity premium. When it comes to business cycle performance the model's progress has been more limited: consumption is still too volatile compared to the data, whereas investment is still too smooth. These are important areas for potential improvement in this framework.Wealth ; Stock market