356 research outputs found
Optimal simple monetary policy rules and welfare in a DSGE Model for Hungary
We explore the properties of welfare-maximizing monetary policy in a medium-scale DSGE model for Hungary. In order to make our results operational from a policymakerâs perspective, we approximate the optimal policy rule with a set of simple rules reacting only to observable variables. Our results suggest that âscience of monetary policyâ that is found robust in simple models, holds in this medium-scaled setting as well. That is, the welfare-maximizing policy that aims to eliminate distortions associated with nominal rigidities can be approximated by a simple inflation targeting rule. Adding exchange rate into the feedback rule only marginally improves the stabilization properties of the policy rule. However, a rule reacting to wage inflation can be significantly welfare-improving. These results may suggest that in our medium-sized model the distortions associated with sticky wage setting have at least as important welfare implications as those related to the price stickiness in product markets.monetary policy, central banking, policy design
Numerical Validation of a Diurnal Streamflow-Pattern-Based Evapotranspiration Estimation Method
The evapotranspiration (ET) estimation method by Gr
ibovszki et al. (2010b) has so far
been validated only at one catchment because good q
uality discharge time series with the required
high enough temporal resolution can probably be fou
nd at only a handful of watersheds worldwide. To
fill in the gap of measured data, synthetic groundw
ater discharge values were produced by a 2D finite
element model representing a small catchment. Geome
trical and soil physical parameters of the
numerical model were changed systematically and it
was checked how well the model reproduced the
prescribed ET time series. The tests corroborated t
hat the ET-estimation method is applicable for
catchments underlain by a shallow aquifer. The slop
e of the riparian zone has a strong impact on the
accuracy of the ET results when the slope is steep,
however, the method proved to be reliable for
gentle or horizontal riparian zone surfaces, which
are more typical in reality. Likewise, errors sligh
tly
increase with the decrease of riparian zone width,
and unless this width is comparable to the width of
the stream (the case of a narrow riparian zone), th
e ET estimates stay fairly accurate. The steepness
of
the valley slope had no significant effect on the r
esults but the increase of the stream width (over 4
m)
strongly influences the ET estimation results, so t
his method can only be used for small headwater
catchments. Finally, even a magnitude change in the
prescribed ET rates had only a small effect on the
estimation accuracy. The soil physical parameters,
however, strongly influence the accuracy of the
method. The model-prescribed ET values are recovere
d exactly only for the sandy-loam aquifer,
because only in this case was the model groundwater
flow system similar to the assumed, theoretical
one. For a low hydraulic conductivity aquifer (e.g.
clay, silt), root water uptake creates a considera
bly
depressed water table under the riparian zone, ther
efore the method underestimates the ET. In a sandy,
coarser aquifer the flow lines never become vertica
l even bellow the root zone, so the method
overestimates the ET rate, thus the estimated ET va
lues need to be corrected. Luckily the prescribed
and estimated ET rates express a very high linear c
orrelation, so the correction can be obtained by th
e
application of a constant, the value of which solel
y depends on soil type
A növĂ©nyi alapĂș hĂșsimitĂĄtumok fogyasztĂłi preferenciĂĄinak vizsgĂĄlata MagyarorszĂĄgon = Consumer Preferences of Plant-Based Meat Substitutes in Hungary
Modern robotikai technolĂłgiai ismeretek oktatĂĄsa âTeljes spektrumĂșâ oktatĂĄsi mĂłdszerrel : Application of âfull-spectrumâ teaching methods in the education of modern robotic technology
Napjainkban a feltörekvĆ technolĂłgiĂĄk Ă©s eszközök jelentĆs kihĂvĂĄst jelentenek az oktatĂĄsi intĂ©zmĂ©nyeknek Ă©s oktatĂłknak egyarĂĄnt. Jelen cikk megkĂsĂ©rli a multidiszciplinĂĄris mƱszaki tudĂĄs ĂĄtadĂĄsĂĄt modern oktatĂĄsi mĂłdszertan hasznĂĄlatĂĄval egy vĂĄltozĂł tudĂĄshĂĄtterƱ hallgatĂłsĂĄgnak. A bemutatott mĂłdszertan alapkĂ©pzĂ©sben indult bevezetĆ robotikai kurzusban kerĂŒlt felhasznĂĄlĂĄsra. Jelen mĂłdszertan egyesĂti a hagyomĂĄnyos pedagĂłgiai mĂłdszereket a modernekkel, mint a projekt-alapĂș feladatok, önĂ©rtĂ©kelĂ©s Ă©s projektbemutatĂłk, hasonlĂłan egy miniszimpĂłziumhoz. A hallgatĂłk visszajelzĂ©se alapjĂĄn az Ășj mĂłdszertan ĂgĂ©retes, az eredmĂ©nyek egy rĂ©sze igazolja elĆzetes elvĂĄrĂĄsainkat, ugyanakkor felfedi a javĂtĂĄsi lehetĆsĂ©geket mĂĄs tĂĄrgyak esetĂ©ben is
State feedback design considering overexcitation
The state equation describing the relationship between the input signal
u(t), the state variable x(t) and the output signal y(t) of a linear, time invariant
nth order SISO process is:\textit dx/dt=Ax+Bu, y=Cx+Du. The transfer function between the output signal
and the input signal of the process is: \textity(s)/u(s)=Wp(s) and the time constants
characterizing the delays of signals due to energy storage elements result
from the eigenvalues of the state matrix A. In the classical feedback control
system, the controller computes the control signal according to the
expression u(s)= Wc(s)[ua(s)-y(s)]. The reduction of signal delay in the process is
implemented by the PID algorithm described by the transfer function
Wc(s) that accelerates the feedback system by \textitoverexciting the control signal to a
specified extent. The reduction of signal delay in the process can also be
implemented by negative feedback of the state variables x. If the process is
state controllable and the control signal is computed according to the
algorithm u=kcua-Fx, the time constants of the feedback system can be
freely specified by appropriate selection of F and kc. The design of the
feedback gain F can be performed using the \textitAckermann formula; the system is
accelerated by means of \textitoverexcitation of the control signal to an appropriate extent even
in this case. The paper presents the fact that the gain can be chosen
according to kc=[C(A-BF-1B]-1CA-1B, and the overexcitation ratio of the
control signal can be calculated using the relationship u(0)/u(∞ )=[1+F(A-BF)-1B]-1. This
overexcitation ratio is in connection with the rate of pole transfers that
can be expressed analytically. It occurs frequently that the state variables
x of the process cannot play any part in the computation of the control
signal since the state variables cannot be measured. In such cases, the
state feedback can be implemented from the state variables x*(t) of a state
observer according to the expression u=kcuaFx*. The paper presents the
fact that the state feedback implemented based on the state observer - as
opposed to the common concept - can also be interpreted as a state
feedback of the process model, with the task of computing the control signa
l
that fulfils the requirements of acceleration. This signal is applied at the
input of both the process model and the real process
Evapotranspiration Calculation on the Basis of the Riparian Zone Water Balance
Riparian forests have a strong influence on groundwater levels and groundwater sustainedstream baseflow. An empirical and a hydraulic version of a new method were developed to calculateevapotranspiration values from riparian zone groundwater levels. The new technique was tested on thehydrometeorological data set of the HidegvĂz Valley (located in Sopron Hills at the eastern foothills ofthe Alps) experimental catchment. Evapotranspiration values of this new method were compared tothe Penman-Monteith evapotranspiration values on a half hourly scale and to the White methodevapotranspiration values on a daily scale. Sensitivity analysis showed that the more reliable hydraulicversion of our ET estimation technique is most sensitive (i.e., linearly) to the values of the saturatedhydraulic conductivity and specific yield taken from the riparian zone
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