Efficiency in audio processing : filter banks and transcoding

Audio transcoding is the conversion of digital audio from one compressed form A to another compressed form B, where A and B have different compression properties, such as a different bit-rate, sampling frequency or compression method. This is typically achieved by decoding A to an intermediate uncompressed form, and then encoding it to B. A significant portion of the involved computational effort pertains to operating the synthesis filter bank, which is an important processing block in the decoding stage, and the analysis filter bank, which is an important processing block in the encoding stage. This thesis presents methods for efficient implementations of filter banks and audio transcoders, and is separated into two main parts. In the first part, a new class of Frequency Response Masking (FRM) filter banks is introduced. These filter banks are usually characterized by comprising a tree-structured cascade of subfilters, which have small individual filter lengths. Methods of complexity reduction are proposed for the scenarios when the filter banks are operated in single-rate mode, and when they are operated in multirate mode; and for the scenarios when the input signal is real-valued, and when it is complex-valued. An efficient variable bandwidth FRM filter bank is designed by using signed-powers-of-two reduction of its subfilter coefficients. Our design has a complexity an order lower than that of an octave filter bank with the same specifications. In the second part, the audio transcoding process is analyzed. Audio transcoding is modeled as a cascaded quantization process, and the cascaded quantization of an input signal is analyzed under different conditions, for the MPEG 1 Layer 2 and MP3 compression methods. One condition is the input-to-output delay of the transcoder, which is known to have an impact on the audio quality of the transcoded material. Methods to reduce the error in a cascaded quantization process are also proposed. An ultra-fast MP3 transcoder that requires only integer operations is proposed and implemented in software. Our implementation shows an improvement by a factor of 5 to 16 over other best known transcoders in terms of execution speed

Scaling Of MDOF Micro-Macro Bilateral Control Teleoperation System Using Standardized Modal Space

In future, robots and mechatronic system are required to support human, they should have a lot of abilities such as recognition of the real world based on the complicated human action to environment based on human sensation and so on. The word “Haptic” means sense of touch and haptic information is studied as the third type of multimedia information. Unlike audio and visual information which is transmitted to one direction (unilateral), haptic information is bidirectional information (bilateral), which applied “law of action and reaction” a tactile information in bilateral information. Thus, a bilateral control system with master and slave manipulator to transmit the information bilaterally has been researched. In this thesis, bilateral teleoperation control system is implemented in single link planar and two link planar manipulator which consisted of master and slave system. The modelling of bilateral teleoperation control system is designed with the integration of Disturbance Observer (DOB), Reaction Force/Torque Observer (RFOB)/(RTOB), position controller and force controller. Then further research on micro-macro bilateral teleoperation control system is done on multi degree-of-freedoms (MDOF) which is two link planar manipulator. The micro-macro bilateral control teleoperation system provides the human operator with a sense of feel to a micro or macro environment as if it is in the same scale environment. However, the micro-macro bilateral control system of this thesis consists of same size structure between master and slave manipulator. Thus a standardized modal space method is proposed to achieve for MDOF micro-macro bilateral control teleoperation system. This method able to scale the force and position information between master slave system. It is a novel method for transmission of force and motion in macro environment in order to realize the physical support for the macro activities. Nevertheless, this proposed method able to scale the haptic information between the master and slave system accordingly. To validate the performance of common mode and differential mode of the proposed method, 4 cases of free and contact motion experiments with different nominal mass ratio between master and slave system are conducted. Then the root-mean-square deviation of the nominal mass ratio and scaling α gain from 4 different cases is 1.12×10−5 and 2.55×10−5 fo

Secure Massive MIMO Communication with Low-resolution DACs

In this paper, we investigate secure transmission in a massive multiple-input multiple-output (MIMO) system adopting low-resolution digital-to-analog converters (DACs). Artificial noise (AN) is deliberately transmitted simultaneously with the confidential signals to degrade the eavesdropper's channel quality. By applying the Bussgang theorem, a DAC quantization model is developed which facilitates the analysis of the asymptotic achievable secrecy rate. Interestingly, for a fixed power allocation factor $\phi$, low-resolution DACs typically result in a secrecy rate loss, but in certain cases they provide superior performance, e.g., at low signal-to-noise ratio (SNR). Specifically, we derive a closed-form SNR threshold which determines whether low-resolution or high-resolution DACs are preferable for improving the secrecy rate. Furthermore, a closed-form expression for the optimal $\phi$ is derived. With AN generated in the null-space of the user channel and the optimal $\phi$, low-resolution DACs inevitably cause secrecy rate loss. On the other hand, for random AN with the optimal $\phi$, the secrecy rate is hardly affected by the DAC resolution because the negative impact of the quantization noise can be compensated for by reducing the AN power. All the derived analytical results are verified by numerical simulations.Comment: 14 pages, 10 figure

Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

We develop the method for the calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energy. It is extended for nuclear reactions at low energy and intermediate energy by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with the 30 experimental data within 10 percent accuracy.The comparison between the numerical results and the 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies the quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root mean square radii of these nuclei can be extracted from above comparison based on the improved Glauber model, which indicate clearly the halo structures of these nuclei. Especially, it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.Comment: 15 pages,2 figures. Communucations in Theoretical Physics, (2003) in pres

Long-range transverse Ising model built with dipolar condensates in two-well arrays

Dipolar Bose-Einstein condensates in an array of double-well potentials realize an effective transverse Ising model with peculiar inter-layer interactions, that may result under proper conditions in an anomalous first-order ferromagnetic-antiferromagnetic phase transition, and non-trivial phases due to frustration. The considered setup allows as well for the study of Kibble-Zurek defect formation, whose kink statistics follows that expected from the universality class of the mean-field one-dimensional transverse Ising model. Furthermore, random occupation of each layer of the stack leads to random effective Ising interactions and local transverse fields, that may lead to the Anderson-like localization of imbalance perturbations.National Natural Science Foundation of China/11575063National Natural Science Foundation of China/11374375National Natural Science Foundation of China/11574405German-Israel Foundation/I-1024-2.7/2009Tel Aviv UniversityNational Science Foundation (US)Binational Science Foundation (US-Israel)DFG/RTG/1729DFG/FOR/224

EFFECTS OF EIGHT-WEEK WHOLE-BODY VIBRATION TRAINING ON POSTURAL STABILITY IN ELDERLY ADULTS

The aim of this study was to examine the effects of an eight-week whole-body vibration training (WBVT) on postural stability (PS) in elderly people. Twenty-two elderly people with normal ability of movement were randomized into the WBVT group (WBVTG, 13 elders), and the control group (CG, 9 elders). The WBVTG underwent WBV training for 8 weeks. The CG did not take any physical training. The PS performance was evaluated by the Biodex Balance System to measure the overall (O), anterior-posterior (AP), and medial-lateral (ML) stability at level 2 (unstable) and level 8 (stable). One-way ANCOVA were used for statistical analysis, with =0.05. Results showed that after training, the WBVG significantly improved the O, AP, and ML stability performance at level 2, and also the O and ML stability performance at level 8

Hyperpartisan News and Articles Detection Using BERT and ELMo

Fake news and articles are misleading the readers. This leads to the increasing studies of fake news article detection over the decades. Hyperpartisan news is news riddled with twisted and untruth and extremely one-sided. This news can spread more successfully than others. Besides that, hyperpartisan news can mimic the form of regular news articles. This study aims to identify and classify the hyperpartisan news with BERT and ELMo. Two distinct models, BERT and ELMo, were created to classify hyperpartisan news from two datasets, namely by-article and by-publisher. Few other models with different settings and training designed to test and optimise the performance of both models. The results of the optimised BERT and ELMo models can achieve 68.4% and 60.8%, respectively