Temperature-Dependence of the Amide-Ⅰ Frequency Map for Peptides and Proteins

In our recent work [Phys. Chem. Chem. Phys. 11, 9149 （2009）], a molecular-mechanics force field-based amidc-Ⅰ vibration frequency map （MM-map） for peptides and proteins was constructed. In this work, the temperature dependence of the MM-map is examined based on high-temperature molecular dynamics simulations and infrared （IR） experiments. It is shown that the 298-K map works for up to 500-K molecular dynamics trajectories, which reasonably reproduces the 88 ℃ experimental IR results. Linear IR spectra are also simulated for two tripeptides containing natural and unnatural amino acid residues, and the results are in reasonable agreement with experiment. The results suggest the MM-map can be used to obtain the temperature-dependent amide-Ⅰ local mode frequencies and their distributions for peptide oligomers, which is useful in particular for understanding the IR signatures of the thermally unfolded species.

An application of matching pursuit time-frequency decomposition method using multi-wavelet dictionaries

In the time-frequency analysis of seismic signals, the matching pursuit algorithm is an effective tool for non-stationary signals, and has high time-frequency resolution and a transient structure with local self-adaption. We expand the time-frequency dictionary library with Ricker, Morlet, and mixed phase seismic wavelets, to make the method more suitable for seismic signal time-frequency decomposition. In this paper, we demonstrated the algorithm theory using synthetic seismic data, and tested the method using synthetic data with 25% noise. We compared the matching pursuit results of the time-frequency dictionaries. The results indicated that the dictionary which matched the signal characteristics better would obtain better results, and can reflect the information of seismic data effectively.

Mapping analysis of vibrating fundamental frequency for simple-supported elastic rectangle-plates with concentrated mass

By conformal mapping theory, a trigonometric interpolation method between odd and even sequences in rectangle boundary region was provided, and the conformal mapping function of rectangle-plate with arc radius between complicated region and unite dish region was carried out. Aiming at calculating the vibrating fundamental frequency of special-shaped, elastic simple-supported rectangle-plates, in the in-plane state of constant stress, the vibration function of this complicated plate was depicted by unit dish region. The coefficient of ftmdamental frequency was calculated. Whilst, taking simple-supported elastic rectangle-plates with arc radius as an example, the effects on fundamental frequency caused by the concentrated mass and position, the ratio of the length to width of rectangle, as well as the coefficient of constant in-plane stress were analyzed respectively.

Estimation of peak runoff and frequency in an ungauged stream of a forested watershed for flood hazard mapping

Kaynasli District in the western Black Sea region of Turkey has long been vulnerable to frequent flood damage due to the establishment of settlements within and around stream channels without regard to fluctuating peakstreamflow frequencies. The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage. Daily total precipitation data for 1975–2010 were analysed, and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture. This was then calculated for different frequencies of the yearly maximum discharge. Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering CentersRiver Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek. As the main creek of the sub-watershed, its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed, and subsequently was seen as having a high level of casualty risk. It was concluded that the one dimensional model could be useful, but 2D models were more suitable for these types of watersheds.

High-precision frequency attenuation analysis and its application

Based on seismic attenuation theory in a fluid-filled porous medium, we improve conventional methods of low-frequency shadow analysis （LFSA） and energy absorption analysis （EAA） and propose a high-precision frequency attenuation analysis technology. First, we introduce the method of three-parameter wavelet transform and the time-frequency focused criterion and develop a high-precision time-frequency analysis method based on an adaptive three-parameter wavelet transform, which has high time-frequency resolution with benefit to LFSA and can obtain a single-peaked spectrum with narrow side-lobes with benefit to EAA. Second, we correctly compute absorption coefficient by curve fitting based on the nonlinear Nelder-Mead algorithm and effectively improve EAA precision. Practical application results show that the proposed frequency attenuation analysis technology integrated with LFSA and EAA can effectively predict favorable zones of carbonate oolitic reservoir. Furthermore, reservoir prediction results based on LFSA correspond with EAA. The new technology can effectively improve reservoir prediction reliability and reduce exploration risk.

Conformal analysis of fundamental frequency of vibration of simple-supported elastic ellipse-plates with concentrated substance

Aimed at calculating the fundamental frequency of vibration of special-shaped, simple-supported elastic plates, Conformal Mapping theory is applied, and the mathematical method of trigonometric interpolation with interpolation points mutual iterative between odd and even sequences in boundary region is provided, as well as the conformal mapping function which can be described by real number region between complicated region and unit dish region is carried out. Furthermore, in the in-plane state of constant stress, vibrating function is completed by unit dish region method for simple-supported elastic plates with concentrated substance of complicated vibrating region, and the coefficient of fundamental frequency of the plate is analyzed. Meanwhile, taking simple-supported elastic ellipse-plates as an example, the effects on fundamental frequency caused by eccentric ratio, the coefficient of constant in-plane stress, as well as the concentrated substance mass and positions are analyzed respectively.

Application of time–frequency entropy from wake oscillation to gas–liquid flow pattern identification

Gas–liquid two-phase flow abounds in industrial processes and facilities. Identification of its flow pattern plays an essential role in the field of multiphase flow measurement. A bluff body was introduced in this study to recognize gas–liquid flow patterns by inducing fluid oscillation that enlarged differences between each flow pattern. Experiments with air–water mixtures were carried out in horizontal pipelines at ambient temperature and atmospheric pressure. Differential pressure signals from the bluff-body wake were obtained in bubble, bubble/plug transitional, plug, slug, and annular flows. Utilizing the adaptive ensemble empirical mode decomposition method and the Hilbert transform, the time–frequency entropy S of the differential pressure signals was obtained. By combining S and other flow parameters, such as the volumetric void fraction β, the dryness x, the ratio of density φ and the modified fluid coefficient ψ, a new flow pattern map was constructed which adopted S（1–x）φ and （1–β）ψ as the vertical and horizontal coordinates, respectively. The overall rate of classification of the map was verified to be 92.9% by the experimental data. It provides an effective and simple solution to the gas–liquid flow pattern identification problems.

New Iterated Decoding Algorithm Based on Differential Frequency Hopping System

A new iterated decoding algorithm is proposed for differential frequency hopping (DFH) encoder concatenated with multi-frequency shift-key (MFSK) modulator. According to the character of the frequency hopping (FH) pattern trellis produced by DFH function, maximum a posteriori (MAP) probability theory is applied to realize the iterate decoding of it. Further, the initial conditions for the new iterate algorithm based on MAP algorithm are modified for better performance. Finally, the simulation result compared with that from traditional algorithms shows good anti-interference performance.

Novel analysis method for the spurious spectrum of direct digitalfrequency synthesizer in the presence of phase truncation

Based on the analysis of the spurious introduced by phase accumulation truncation which was made by Nicholas, a new simplified algorithm for spurious spectrum in the presence of phase truncation is presented by using the mapping mathematics and number theoretic method, it is possible to precisely analyze the spurious location and the spurious amplitude introduced by phase truncation in practical applications by computer.

A GEOMETRIC THEORY IN INVESTIGATION ON MODE LOCALIZATION AND FREQUENCY LOCI VEERING PHENOMENA

According to the mapping theory in complex plane, the geometric features of eigen frequency loci of systems undergoing free vibrations are investigated. It is concluded that the phenomena of curve coalescence and veering can be described in a unified manner from the singularities of mapping from the complex parameter plane onto the complex frequency plane. The formation of a branch point in the parameter Space is the foundation of explaining localization and veering phenomena. By the use of condensation to reduce the dimension of a system, the scope of application of the geometric theory is widely expanded. The theory is applied to examples to verify the validity of the proposed approach. The present work is an improvement and extension of recent work by M. S. Traintafyllou et al..

GIS-Based Frequency Ratio Method for Identification of Potential Landslide Susceptible Area in the Siwalik Zone of Chatara-Barahakshetra Section, Nepal

The hilly regions of Nepal are potential for land sliding in rainy season. Lying between two major thrusts: Main Frontal Thrust (MFT) and Main Boundary Thrust (MBT), the rocks of Siwalik zone are very weak and fragile. Shallow and deep landslides are very common in the Siwalik zone during heavy and continuous rainfall. The landslide in the busy road and agglomerate settlements are destroying the life and properties every year in rainy season. This study aims to develop a landslide susceptibility map of Chatara-Barahakshetra area, Siwalik zones of eastern Nepal by the means of frequency ratio model. The paper utilized the remote sensing and GIS to develop a landslide susceptibility map. Total of 382 landslide polygons were mapped from Google earth and by field verification. The validation results showed that the success rate curve with 72.55 percentage of the area lying under the curve and the prediction rate curve with 71.73 percentage of the area lying under the curve indicating that prediction ability of the Frequency Ratio model. These landslide susceptibility maps can be used as a planning tool by prioritizing areas for controlling the landslide effects. More than 71% success rate indicate that frequency ratio model is suitable model for the landslide susceptibility in the study area.

On ionosphere-delay processing methods for single-frequency precise-point positioning

In single-frequency precise-point positioning of a satellite,ionosphere delay is one of the most important factors impacting the accuracy. Because of the instability of the ionosphere and uncertainty of its physical properties, the positioning accuracy is seriously limited when using a precision-limited model for correction. In order to reduce the error, we propose to introduce some ionosphere parameter for real-time ionosphere-delay estimation by applying various mapping functions. Through calculation with data from the IGS（ International GPS Service） tracking station and comparison among results of using several different models and mapping functions, the feasibility and effectiveness of the new method are verified.

Combined Signal Detection Method in Differential Frequency Hopping System

In order to enhance communication reliability of differential frequency hopping system, a receiver implemented with the concatenation of an optimal subblock-by-subblock maximum a posteriori probability (OBB-MAP) detector and a soft-decision Turbo decoder is proposed and validated in both AWGN and Rayleigh flat fading channels. It is shown that the OBB-MAP decoder can iteratively decode a cyclic trellis, and back-search the trellis for any state to obtain estimates for the prior information bits which can be employed by soft-decision Turbo decoder. The proposed receiver achieves a better bit error rate(BER) performance than maximum likelihood sequence estimation(MLSE) detector employing Viterbi algorithm. The simulation results demonstrate that the combined signal detection method improves communication quality.

基于EM的MIMO-OFDM系统MAP信道估计算法

最大后验概率(maximum a posteriori,MAP)信道估计算法应用于MIMO-OFDM系统时将带来大规模矩阵求逆和乘积运算,且OFDM符号的数据传输效率随着发送天线的增多逐渐下降。针对这些弊端,提出一种基于期望最大化(expectation maximum,EM)的MAP信道估计算法,并分析了算法的性能。该算法利用EM算法把多输入输出信道估计问题化简为一系列独立的单输入输出问题,避免了大规模矩阵运算,降低了MAP算法的计算复杂度;为进一步改善MAP算法的数据传输效率及其估计性能,可通过对多个连续的OFDM符号进行联合信道估计。通过仿真实验证明了该算法的有效性。

一种改善的MIMO-OFDM系统MAP信道估计

在MIMO-OFDM系统下提出一种最大后验概率(MAP)信道估计算法.该算法利用期望最大化(EM)算法把MIMO信道估计分解为一系列独立的SISO信道问题,降低了MAP算法的计算复杂度.同时,根据在角域内不同发送和接收天线间的信道可近似为空间不相关,利用最有用抽头(MST)技术来减小噪声对估计性能的影响.仿真实验表明,与传统LS和EM算法相比,所提算法在低信噪比下具有较低的估计误差.

Quasi-periodically Forced Logistic Map with Weak Liouvillean Frequency

Consider a class of quasi-periodically forced logistic maps T×[0,1]■:(θ,x)→(θ+ω,c(θ)x(1-x))(T=R/Z),whereωis an irrational frequency and c(θ)is a specific bimodal function.We prove that under weak Liouvillean condition on frequency,the strange non-chaotic attractor occurs with negative Lyapunov exponent.This extends the result in[Bjerklov,CMP,2009].

煤矿带式输送机矸石识别新方法

带式输送机煤矸石高效分拣是实现煤炭资源绿色开采的重要途径,其核心问题是煤和矸石的快速精准识别。因此提出了一种基于电磁波探测的带式输送机煤矸石识别方法。首先,结合电磁波信号在煤矸石分界表面的反射和透射现象,分析了探测过程中电磁信号的传播特性;然后,利用连续小波变换(CWT)将电磁信号映射为二维时频图,并将其作为输入对MobileNetV2煤矸石识别模型进行训练和验证,输出识别结果。实验结果表明,MobileNetV2模型的平均准确率和平均F1分别可达97.58%和92.75%,验证了所提方法对带式输送机煤矸石识别的可行性和有效性。

一种有效的MIMO-OFDM系统MAP信道估计

对于MIMO-OFDM系统,最大后验概率(MAP)信道估计算法可通过期望最大化(EM)算法降低计算复杂度,但将产生误差平底(errorfloor)现象。并且,系统的数据传输效率受限于发送端天线的数目。针对这些问题,该文提出了一种有效的MAP信道估计算法,并分析了算法的性能。所提算法在利用EM算法减小MAP算法计算复杂度的基础上,利用角域内信道间的独立性降低估计误差。为改善系统数据传输效率及估计性能,通过多个OFDM符号进行联合的信道估计。仿真实验验证了所提算法拥有更好的估计性能和数据传输效率。

基于修正EM的高效MIMO-OFDM系统MAP信道估计算法

针对MIMO—OFDM系统的基于期望最大化（EM）的最大后验（MAP）信道估计算法带来的误差地板（EF）现象及较低的数据传输效率，提出了一种基于修正EM的高效的MAP信道估计算法。该算法首先引入一种更精确的系统模型来改善基于EM的MAP估计算法在高信噪比下的EF现象，其次利用多个正交频分复用（OFDM）符号进行联合信道估计来提高系统的数据传输效率和信道估计的均方误差（MSE）性能。仿真实验结果表明这种估计算法改善了误差地板现象。同时拥有更低的估计误差和更高的数据传输效率。

MAP-CA在视频压缩中的应用

信息时代的重要特征是信息的数字化,但数字化的视频数据量是非常巨大的。为了使数字化的视频信号更有效地传输,对其进行压缩势在必行。应用MAP-CA这个DSP芯片可以对视频图像进行MPEG-4标准的压缩,压缩比可以达到1000:1。在公用电话线上就可以连续传输视频,并能保持图像的质量,最高图像清晰度为768×576,可以达到接近DVD的画面效果。