演化观中的声调类型:西南吴语案例

文章根据一手录音材料,从演化的角度来描写、分析吴语西南部的婺州和处衢片45个方言点的声调类型。西南吴语声调和语音的最大特点是:发声变化大而曲拱丰富。发声变化大主要有两点:有70%强的调系丢失了吴语最重要的气声特征,从而失去下域;有9个调系增生了假声/张声上域,占总数20%。曲拱丰富表现在:1)包括凹调、弯降和凸升的“拐调”特别多;2)新发现四种拐调调型:三种凹调和一种高凸升;3)作为极端例子,有两个调系中存在四个凹调的对立。确定调型应按类型学标准,而不是以往的音位或区别特征标准。文章对类型学标准的权重问题也做了讨论。

罗伯特·威尔逊作品中的“声域”与“寂静”

2022年11月,南京大学艺术学院邀请英国伦敦大学的戏剧专家玛丽亚·谢弗索娃进行线上讲座。鉴于她对于美国知名戏剧导演罗伯特·威尔逊长期的研究,且出版过学术专著,主办方提议她做一场罗伯特·威尔逊的专题演讲。之后,根据她的演讲稿,又结合她相关的学术出版加以补充完善,整理出这一篇演讲类型的学术文章。谢弗索娃介绍了威尔逊近期的艺术实践,并梳理了其从“无声”到“有声”的创作历程。她结合具体案例,指出威尔逊倾向于用对位法处理各个舞台元素间的关系,使其在平行的轨道上运行,而非相互融合。顺应这种导演观念,威尔逊作品中的声域与寂静在独立的状态下进行互动,从而构成了独特的声景。

声音导鱼技术的分析与展望

声音导鱼技术对保护鱼类有重要的实际价值和深远意义,其研究重点是声音如何让鱼类产生趋避行为及如何准确的让鱼类产生趋或者避的行为。从生理学和行为学的角度对声音导鱼的生物学基础进行了分析;讨论了声音导鱼的关键技术,包括鱼类趋避行为对声音的响应关系、鱼类声域的确定、鱼类声音信号的采集、鱼类声波信号的数字化处理以及实际声场中声波的叠加技术等,并根据声音对鱼类诱驱作用的原理建立了一个声音导鱼的大坝模型,分析了大坝实现声音诱驱鱼的关键要素;展望了声音导鱼技术的发展前景和方向。

新时期初中音乐课堂合唱教学策略分析

初中音乐课堂合唱教学是初中音乐教学的重要方式,在教学过程中采用合理的教学策略,不仅能够增强学生们的合唱效果,还能进一步提高音乐教师的教学水平。文章从音乐课堂合唱教学内容及目标、合唱曲目的选择、合唱教学方式的应用等方面进行了阐述,并在此基础上行提出初中音乐课堂合唱教学中需要注意的若干问题,以供相关人员参考。

PARALLEL COMPUTATION OF 3-D HYPERSONIC FLOWS ON UNSTRUCTURED HYBRID MESHES

A parallel virtual machine （PVM） protocol based parallel computation of 3-D hypersonic flows with chemical non-equilibrium on hybrid meshes is presented. The numerical simulation for hypersonic flows with chemical non-equilibrium reactions encounters the stiffness problem, thus taking huge CPU time. Based on the domain decomposition method, a high efficient automatic domain decomposer for three-dimensional hybrid meshes is developed, and then implemented to the numerical simulation of hypersonic flows. Control equations are multicomponent N-S equations, and spatially discretized scheme is used by a cell-centered finite volume algorithm with a five-stage Runge-Kutta time step. The chemical kinetic model is a seven species model with weak ionization. A point-implicit method is used to solve the chemical source term. Numerical results on PC-Cluster are verified on a bi-ellipse model compared with references.

Scale effects on non-cavitation hydrodynamics and noise of highly-skewed propeller in wake flow

Regarding the scale effects on propeller＇s noncavitation hydrodynamics and hydroacoustics, three similar 7bladed highly-skewed propellers in the wake flow are addressed with diameters of 250, 500 and 1 000 mm, respectively. The discrete line-spectrum noise and its standardized spectrum level scaling law, together with the total sound pressure level are analyzed. The non-cavitation noise predictions are completed by both the frequency domain method and the time domain method. As a fluctuated noise source, the time-dependent fluctuated pressure and normal velocity distribution on propeller blades are obtained by the unsteady Reynolds-averaged Navier-Stokes （ URANS ） simulation. Results show that the pressure coefficient distribution of three propellers on the 0.7R section is nearly superposed under the same advance ratio. The periodic thrust fluctuation of three propellers can exactly reflect the tonal components of the axial passing frequency （APF） and the blade passing frequency （BPF）, and the fluctuation enhancement from the small to the middle propeller at the BPF is greater than that from the middle to the big one. By the two noise prediction methods, the increment of the total sound pressure level from the small to the big propeller differs by 2.49 dB. Following the standardized scaling law, the spectrum curves of the middle and big propellers are nearly the same while significantly differing from the small one. The increment of both the line-spectrum level and the total sound pressure increases with the increase in diameter. It is suggested that the model scale of the propeller should be as large as possible in engineering to reduce the prediction error of the empirical scalin~ law and weaken the scale effects.

电声扩音与文艺演出

随着科学技术的发展,"电声"技术已成为各种戏剧歌舞演也中处理和调解音质、扩大音量的重要手段."电声"扩音不仅是为了把戏剧、歌舞在舞台上演出的自然声源放大,更重要的是在不同的舞台环境,对演唱者和表演者的声域,通过电声器材的技术处理,进行美化,以达到弥补演员声音的不足,改善建声条件的缺陷。

Stability of finite difference numerical simulations of acoustic logging-while-drilling with different perfectly matched layer schemes

In acoustic logging-while-drilling （ALWD） finite difference in time domain （FDTD） simulations, large drill collar occupies, most of the fluid-filled borehole and divides the borehole fluid into two thin fluid columns （radius -27 mm）. Fine grids and large computational models are required to model the thin fluid region between the tool and the formation. As a result, small time step and more iterations are needed, which increases the cumulative numerical error. Furthermore, due to high impedance contrast between the drill collar and fluid in the borehole （the difference is 〉30 times）, the stability and efficiency of the perfectly matched layer （PML） scheme is critical to simulate complicated wave modes accurately. In this paper, we compared four different PML implementations in a staggered grid finite difference in time domain （FDTD） in the ALWD simulation, including field-splitting PML （SPML）, multiaxial PML（M- PML）, non-splitting PML （NPML）, and complex frequency-shifted PML （CFS-PML）. The comparison indicated that NPML and CFS-PML can absorb the guided wave reflection from the computational boundaries more efficiently than SPML and M-PML. For large simulation time, SPML, M-PML, and NPML are numerically unstable. However, the stability of M-PML can be improved further to some extent. Based on the analysis, we proposed that the CFS-PML method is used in FDTD to eliminate the numerical instability and to improve the efficiency of absorption in the PML layers for LWD modeling. The optimal values of CFS-PML parameters in the LWD simulation were investigated based on thousands of 3D simulations. For typical LWD cases, the best maximum value of the quadratic damping profile was obtained using one do. The optimal parameter space for the maximum value of the linear frequency-shifted factor （a0） and the scaling factor （β0） depended on the thickness of the PML layer. For typical formations, if the PML thickness is 10 grid points, the global error can be reduced to 〈1% using the optimal PML parameters, and the error will decrease as the PML thickness increases.

个性订制 大众夏朗改装摩雷自由组合三分频

华达乐哥就是一位爱琢磨,爱收藏的纯技术人,从他这为车主所配置的珍藏版摩雷喇叭就要以看得出其对音响改装的态度,也是位有要求、有技术支撑的摩雷迷。在华达的众多案例中我们都可以看到自由组合这几个词,这就足以表明了乐哥对音响系统的订制风格是别具一格的。这套组合的套装喇叭音乐品质更能凸显车主的听音风格和个性。

Dynamic analysis and experimental study of vibro-acoustic system with uncertainties at middle frequencies

To take into account the influence of uncetainties on the dynamic response of the vibro-acousitc structure, a hybrid modeling technique combining the finite element method（FE）and the statistic energy analysis（SEA） is proposed to analyze vibro-acoustics responses with uncertainties at middle frequencies. The mid-frequency dynamic response of the framework-plate structure with uncertainties is studied based on the hybrid FE-SEA method and the Monte Carlo（MC）simulation is performed so as to provide a benchmark comparison with the hybrid method. The energy response of the framework-plate structure matches well with the MC simulation results, which validates the effectiveness of the hybrid FE-SEA method considering both the complexity of the vibro-acoustic structure and the uncertainties in mid-frequency vibro-acousitc analysis. Based on the hybrid method, a vibroacoustic model of a construction machinery cab with random properties is established, and the excitations of the model are measured by experiments. The responses of the sound pressure level of the cab and the vibration power spectrum density of the front windscreen are calculated and compared with those of the experiment. At middle frequencies, the results have a good consistency with the tests and the prediction error is less than 3. 5dB.

Random noise attenuation by f–x spatial projection-based complex empirical mode decomposition predictive filtering

The frequency–space（f–x） empirical mode decomposition（EMD） denoising method has two limitations when applied to nonstationary seismic data. First, subtracting the first intrinsic mode function（IMF） results in signal damage and limited denoising. Second, decomposing the real and imaginary parts of complex data may lead to inconsistent decomposition numbers. Thus, we propose a new method named f–x spatial projection-based complex empirical mode decomposition（CEMD） prediction filtering. The proposed approach directly decomposes complex seismic data into a series of complex IMFs（CIMFs） using the spatial projection-based CEMD algorithm and then applies f–x predictive filtering to the stationary CIMFs to improve the signal-to-noise ratio. Synthetic and real data examples were used to demonstrate the performance of the new method in random noise attenuation and seismic signal preservation.

Improved random noise attenuation using f-x empirical mode decomposition and local similarity

Conventional f-x empirical mode decomposition（EMD） is an effective random noise attenuation method for use with seismic profiles mainly containing horizontal events.However,when a seismic event is not horizontal,the use of f-x EMD is harmful to most useful signals.Based on the framework of f-x EMD,this study proposes an improved denoising approach that retrieves lost useful signals by detecting effective signal points in a noise section using local similarity and then designing a weighting operator for retrieving signals.Compared with conventional f-x EMD,f-x predictive filtering,and f-x empirical mode decomposition predictive filtering,the new approach can preserve more useful signals and obtain a relatively cleaner denoised image.Synthetic and field data examples are shown as test performances of the proposed approach,thereby verifying the effectiveness of this method.

A-E equation of potential field transformations in the wavenumber domain and its application

A shift sampling theory established by author （1997a） is a generalization of Fourier transform computation theory. Based on this theory, I develop an Algorithm-Error （A-E） equation of potential field transformations in the wavenumber domain, which not only gives a more flexible algorithm of potential field transformations, but also reveals the law of error of potential field transformations in the wavenumber domain. The DFT0η η（0.5, 0.5） reduction-to-pole （RTP） technique derived from the A-E equation significantly improves the resolution and accuracy of RTP anomalies at low magnetic latitudes, including the magnetic equator. The law （origin, form mechanism, and essential properties） of the edge oscillation revealed by the A-E equation points out theoretically a way of improving the effect of existing padding methods in high-pass transformations in the wavenumber domain.

Edge enhancement of gravity anomalies and gravity gradient tensors using an improved small sub-domain filtering method

In order to enhance geological body boundary visual effects in images and improve interpretation accuracy using gravity and magnetic field data, we propose an improved small sub-domain filtering method to enhance gravity anomalies and gravity gradient tensors. We discuss the effect of Gaussian white noise on the improved small sub-domain filtering method, as well as analyze the effect of window size on geological body edge recognition at different extension directions. Model experiments show that the improved small sub-domain filtering method is less affected by noise, filter window size, and geological body edge direction so it can more accurately depict geological body edges than the conventional small sub-domain filtering method. It also shows that deeply buried body edges can be well delineated through increasing the filter window size. In application, the enhanced gravity anomalies and calculated gravity gradient tensors of the Hulin basin show that the improved small sub-domain filtering can recognize more horizontal fault locations than the conventional method.

Acoustic multipolar local effects of metamaterial with annular columnar structures

Research of the acoustic local effect of metamaterial is widely used in the fields of environmental science,military industry and biomedicine.In this paper,the metamaterial is designed by annular columnar structures.The acoustic local effect in slender columnar structure with two layers of rings in air is investigated.Results prove that when the plane acoustic wave is incident into the model,complex interference and diffraction occur.And at different frequencies,multipolar acoustic local effect existes and cycle distribution phenomenon is observed.It is noteworthy that this phenomenon has very weak relatedness with the materials and acoustic parameters of the model.The research of this metamaterial design in this paper has definite reference significance in the acoustic communication and amplification of the acoustic signal detection.

Combination of Ecoprofile and Least-cost Model for Eco-network Planning

The protecting requirements and functional connectivity of species in isolated habitat patches are crucial factors of eco-network planning.This study aimed to improve the method of eco-network planning for species conservation.Ecoprofiling was used to group the species by similar behavior types,namely,choice of ecosystem,area requirement,and short distance dispersal abilities.A least-cost model was used to simulate the optimal corridor location to maintain functional connectivity.A combination of ecoprofile and least-cost model was hired to develop an eco-network that promoted species conservation.A case study was also conducted in Beijing,China.In addition to the required ecosystem,habitat area is an important parameter for habitat extraction.Habitat area can remove noise habitat patches because of lacking area.Short-distance dispersal can be used to identify corridor requirements and avoid unnecessary building requirements.Species with various dispersal abilities exhibit significant differences in terms of corridor length and location requirement.Habitat isolation is the main threat for weakly mobile species,and habitat loss is the major risk of mobile species protection.Different species groups also exhibit distinct landscape pattern demands for an eco-network,and the eco-network planning based on specific species can not protect other species.We proposed that a combination of ecoprofile and least-cost model improved the efficiency of species conservation by eco-network planning.

EFFICIENT IMAGE SEGMENTATION FOR SEMANTIC OBJECT GENERATION

This letter presents an efficient and simple image segmentation method for semantic object spatial segmentation. First, the image is filtered using contour-preserving filters. Then it is quasi-flat labeled. The small regions near the contour are classified as uncertain regions and are eliminated by region growing and merging. Further region merging is used to reduce the region number. The simulation results show its efficiency and simplicity. It can preserve the semantic object shape while emphasize on the perceptual complex part of the object. So it conforms to the human visual perception very well.

Multi-Channel Iterative FDE for Single Carrier Block Transmission over Underwater Acoustic Channels

Recently, single carrier block transmission(SCBT) has received much attention in high-rate phase-coherent underwater acoustic communication.However,minimum-mean-square-error(MMSE) linear FDE may suffer performance loss in the severely time dispersive underwater acoustic channel. To combat the channel distortion, a novel multi-channel receiver with maximum ratio combining and a low complex T/4 fractional iterative frequency domain equalization(FDE) is investigated to improve diversity gain and the bit error rate(BER) performance. The proposed method has been verified by the real data from a lake underwater acoustic communication test in November 2011. At 1.8 km, the useful data rates are around 1500 and 3000 bits/s for BPSK and QPSK respectively. The results show the improvements of system performance. Compared with MMSE FDE system, the output SNR improvement is 6.9 d B, and the BER is from 10-3 to no error bits for BPSK. The output SNR improvement is 5.3 d B, and the BER is from 1.91×10-2 to 2.2×10-4for QPSK.

Parallel computation of unified finite-difference time-domain for underwater sound scattering

In this work, we treat scattering objects, water, surface and bottom in a truly unified manner in a parallel finitedifference time-domain （FDTD） scheme, which is suitable for distributed parallel computing in a message passing interface （MPI） programming environment. The algorithm is implemented on a cluster-based high performance computer system. Parallel computation is performed with different division methods in 2D and 3D situations. Based on analysis of main factors affecting the speedup rate and parallel efficiency, data communication is reduced by selecting a suitable scheme of task division. A desirable scheme is recommended, giving a higher speedup rate and better efficiency. The results indicate that the unified parallel FDTD algorithm provides a solution to the numerical computation of acoustic scattering.

Characteristic Analysis of Underwater Acoustic Scattering Echoes in the Wavelet Transform Domain

Underwater acoustic scattering echoes have time–space structures and are aliasing in time and frequency domains. Different series of echoes properties are not identified when incident angle is unknown. This article investigates variations in target echoes of monostatic sonar to address this problem. The mother wavelet with similar structures has been proposed on the basis of preprocessing signal waveform using matched filter, and the theoretical expressions between delay factor and incident angle are derived in the wavelet domain. Analysis of simulation data and experimental results in free-field pool show that this method can effectively separate geometrical scattering components of target echoes. The time delay estimation obtained from geometrical echoes at a single angle is consistent with target geometrical features, which provides a basis for object recognition without angle information. The findings provide valuable insights for analyzing elastic scattering echoes in actual ocean environment.