4,542 research outputs found
What Type Of Framing Message Is More Appropriate With Nine-Ending Pricing?
While the effect of nine-ending prices on purchases has been well documented, studies that examine the impact of this pricing technique in the context of advertisements are rare. This paper examines the joint effect of the pricing technique and message frames on the advertisement efficacy. Since a nine-ending price is compatible with gain-framed messages due to its gain image, we propose that nine-ending pricing strengthens the effectiveness of gain-framed messages (versus loss-framed messages) on the overall advertisement efficacy. The results of two experiments provide support for this hypothesis
Adaptive channel estimation in WCDMA STTD systems
The receiver performance with the use of a space
time transmit diversity (STTD) scheme is more susceptible to
the accuracy of channel estimate than that without the use of
the STTD scheme since the despreading signals suffer from the
effect of crosstalk and the transmit power is equally divided
into multiple transmit antennas. As a result, the efficiency of
channel estimation in the WCDMA STTD system becomes an
important issue more than that in the non-STTD system. In this
paper, an adaptive channel estimator (ACE) is designed to
mitigate the performance degradation due to inaccurate
channel estimation. Numerical results show that the
performance improvement significantly increases with the use
of the proposed ACE, particularly when the channel condition
becomes worse
Optimum pilot pattern for channel estimation in OFDM systems
The performance of channel estimation in orthogonal frequency division multiplexing (OFDM) systems significantly depends on the pilot signal, which is usually scattered in time and frequency domains. For a given pilot density, the authors optimally design the pilot pattern so as to minimize the mean squared error (MSE) of the channel estimate with the use of a general interpolator. The analytic results are verified by computer simulation
Optimum pilot pattern for MMSE channel estimation in single-carrier MIMO systems
The minimum mean squared error (MMSE)
channel estimator (CE) can provide receiver performance better
than the least square (LS) CE. However, the MMSE CE usually
uses a pilot pattern optimally designed for the LS CE. In this
paper, we derive an optimum pilot pattern for the MMSE CE in
single-carrier MIMO systems assuming that both the transmitter
and receiver know the average channel information, such as the
channel correlation matrix and signal to interference and noise
power ratio. Analytic and simulation results show that the
MMSE CE with the use of the proposed pilot pattern can reduce
the MSE compared to the use of one optimized for the LS CEThis work was supported (in part) by the Ministry of Information
& Communications, Korea, under the Information Technology
Research Center (ITRC) Support Program
Design of a Channel-Aware OFDM Transceiver
The transmission performance of an OFDM system can significantly be improved by exploiting the channel characteristics. In this paper, we consider the design of a channel-aware OFDM transceiver whose parameters are adjusted in response to the change of channel condition. To this end, we first estimate the channel state information (CSI), such as the signal to interference power ratio, low order moments of Doppler spectrum and power-delay profile of the channel. The proposed CSI estimator can estimate these CSI parameters altogether in a unique manner by exploiting the autocorrelation properties of the channel impulse response (CIR). Then, we design a CIR estimator and adaptive OFDM modulator that adjust their parameters according to the estimated CSI. Finally, we verify the performance of the proposed OFDM transceiver by computer simulation.This work was in part supported by the Ministry of Information &
Communications, Korea, under the Information Technology Research Center
(ITRC) Support Program
Natural durability of some hardwoods imported into korea for deck boards against decay fungi and subterranean termite in accelerated laboratory tests
This study evaluated the natural durability of seven imported hardwoods (bangkirai, burckella, ipe, jarrah, kempas, malas, and merbau) used for deck boards against decay fungi (Fomitopsis palustris, Gloeophyllum trabeum, Trametes versicolor, and Irpex lacteus) and the subterranean termite (Reticulitermes speratus kyushuensis) in accelerated laboratory tests. Ipe, jarrah, and merbau were very durable to fungal attack, with performance comparable to ACQ-treated wood. Bangkirai, burckella, kempas, and malas were classified as durable or moderately durable, depending on the fungal species tested. All wood species except for merbau were highly resistant to termite attack. Termite resistance was similar to ACQ-treated wood. Merbau showed somewhat less than all other species but still significant termite resistance. These results indicated that selected naturally durable hardwood species could inhibit fungal and termite attacks as effectively as ACQ treatment. The natural durability of wood species tested in this study is most likely due to the biocidal extractive content of the wood
Angle-tolerant linear variable color filter based on a tapered etalon
We propose and fabricate a linear variable color filter (LVCF) that possesses an enhanced angular tolerance in conjunction with a wide linear filtering range (LFR) by taking advantage of an Ag-TiO2-Ag configuration. The TiO2 cavity is tapered in thickness along the device so that the resonance wavelength can be continuously tuned according to the position. In addition, the metal-dielectric-metal structure is overlaid with a pre-designed graded anti-reflection coating in SiO2 to complete the etalon, thereby maximizing the transmission efficiency across the entire device. The tapered dielectric layers in the proposed filter were
fabricated via glancing angle deposition without the help of any mask or moving parts. The center wavelength was scanned from 410 nm to 566 nm, resulting in an LFR of 156 nm, and the overall spectra exhibited an approximate peak transmission of 40% and spectral
bandwidth of 68 nm. The angular tolerance was as large as 45°, incurring a fractional wavelength shift below 4.2%. The resonance wavelength was verified to be linearly dependent on the position, providing a linearity beyond 99%. The proposed LVCF will thus
be actively utilized in a portable micro-spectrometer and spectral scanning device.National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No. 2016R1A2B2010170); ARC Future Fellowship FT110100853
An analytic pricing formula for timer options under constant elasticity of variance with stochastic volatility
Timer options, which were first introduced by Société Générale Corporate and Investment Banking in 2007, are financial securities whose payoffs and exercise are determined by a random time associated with the accumulated realized variance of the underlying asset, unlike vanilla options exercised at the prescribed maturity date. In this paper, taking account of the correlation between the underlying asset price and volatility, we investigate the pricing of timer options under the constant elasticity of variance (CEV) model, proposed by Cox and Ross [10], taking advantage of the approach of asymptotic analysis. Additionally, we validate the pricing precision of the approximate formula for timer options using the Monte Carlo method. We conduct numerical experiments based on our corrected prices and analyze price sensitivities concerning various model parameters, with a focus on the value of elasticity
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