Adaptive quantized target tracking in wireless sensor networks

This paper addresses target tracking in wireless sensor networks (WSN) where the observed system is assumed to evolve according to a probabilistic state space model. We propose to improve the use of the variational filtering (VF) by optimally quantizing the data collected by the sensors. Recently, VF has been proved to be suitable to the communication constraints of WSN. Its efficiency relies on the fact that the online update of the filtering distribution and its compression are executed simultaneously. However, this problem has been used only for binary sensor networks neglecting the transmission energy consumption in a WSN and the information relevance of sensor measurements. Our proposed method is intended to jointly estimate the target position and optimize the quantization level under fixed and variable transmitting power. At each sampling instant, the adaptive method provides not only the estimate of the target position by using the VF but gives also the optimal number of quantization bits per observation. The adaptive quantization is achieved by minimizing the predicted Cramér–Rao bound if the transmitting power is constant for all sensors, and optimizing the power scheduling under distortion constraint if this power is variable. The computation of the predicted Cramér–Rao bound is based on the target position predictive distribution provided by the VF algorithm. The proposed adaptive quantization scheme suggests that the sensors with bad channels or poor observation qualities should decrease their quantization resolutions or simply become inactive in order to save energy.     

Compatibilization of poly(methyl methacrylate) and cellulose nanocrystals through co-continuous phase to enhance the thermomechanical properties

The present study focuses on enhancing the thermomechanical properties of poly(methyl methacrylate) (PMMA), a transparent and biocompatible polymer known for its high strength but limited toughness. The approach involves the development of PMMA/cellulose nanocrystals (CNCs) composites. To improve the interfacial compatibility between PMMA and CNCs, a two-step process is employed. Initially, the CNCs undergo oxidation using sodium periodate, followed by the introduction of amino groups through reductive amination. The aminated CNCs are then covalently bonded to PMMA via an amidation reaction using the “grafting onto” approach. Subsequently, the grafted CNCs are incorporated into the PMMA matrix using the solvent casting method. The resulting composites are extruded into filaments. Elemental composition analysis confirms CNC modification, revealing the presence of 1.6% nitrogen. The modified CNCs exhibit a higher degradation temperature than unmodified CNCs, showing a 50°C increase. The composites' dynamic mechanical analysis (DMA) reveals a 20% improvement in storage modulus (E′) upon incorporating 1.5% of the grafted CNCs into the PMMA matrix. This enhancement is attributed to the formation of co-continuous phases in the composite structure.     

Spirostane and cholestane glycosides from the bulbs of Allium nigrum L

A phytochemical investigation of the fresh bulbs of Allium nigrum L. led to the isolation of new spirostane-type glycosides as two inseparable isomer mixtures, nigrosides A1/A2 (1a/1b) and nigrosides B1/B2 (2a/2b), two new cholestane-type glycosides, nigrosides C and D (3 and 4), together with the known compounds, 25(R,S)-5α-spirostan-2α,3β,6β-trio1-3-O-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (5a/5b) and 25(R,S)-5α-spirostan-2α,3β,6β-trio1 3-O-β-d-glucopyranosyl-(1 → 2)-O-[4-O-(3S)-3-hydroxy-3-methylglutaryl-β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (6a/6b), isolated from this plant for the first time. All structures were elucidated mainly by spectroscopic analysis (1D and 2D NMR experiments, FABMS, HRESIMS) and by comparison with literature data. Cytotoxicity of the isolated compounds was assessed against human colon carcinoma (HT-29 and HCT 116) cell lines. Compounds 5a/5b and 6a/6b were found to be the most active with IC₅₀ values 1.09 and 2.82 μM against HT-29 and 1.59 and 3.45 μM against HCT 116, respectively.     

一种用于说话人头部动画的Viseme语音识别系统

Viseme是在语音驱动说话人头部动画中一种常用的为口形建立的音频-视频模型。本文尝试建立viseme隐马尔可夫模型(HMM),用于驱动说话人头部的语音识别系统,称为前映射系统。为了得到更精确的模型以提高识别率,引入考虑发音口形上下文的Triseme模型。但是引入Triseme模型后,随着模型数量的急剧增加将导致训练数据的严重不足。本文使用决策树状态捆绑方法来缓解这一问题,同时引入了一种以口形相似度为基础的决策树视频问题设计方法。为了比较viseme系统的性能,本文也建立了一个以phoneme为基本HMM模型的语音识别系统。在评价准则上,使用了一种客观评价说话人头部动画的加权识别率。实验表明,以viseme为基本HMM模型的前映射系统可以为说话人头部提供更加合理的口形。     

基于Viseme的连续语音识别系统及Talking Head

为实现听觉/视觉驱动的说话人头部动画,该文给出了一个基于viseme(说话时的基本嘴形单位)的连续语音识别系统。它训练viseme隐马尔可夫模型(HMM),识别语音为viseme图像序列。建模采用triseme的概念来考虑viseme的上下文相关性,但它需要超大量的训练数据。该文根据viseme图像及其相似度权值(VSW)定义视觉问题集,用来建立triseme决策树,以实现triseme的状态捆绑及HMM参数共享。为比较系统性能,基于phoneme(听觉领域的语音基本单位)的语音识别结果也被映射为viseme序列。在评价准则上,定义viseme图像相似度加权识别精度,更全面地考虑输出和参考图像序列的差别,并用嘴形圆度和VSW曲线中的突变点来评估所得viseme序列的平滑性。结果表明,基于viseme的语音识别系统能给出更平滑和合理的嘴形图像序列。     

Design and Implementation of an Algorithm for Cardiac Pathologies Detection on Mobile Phone

The development and the design of telemedicine services have taken a great consideration and care in the domain of wireless communication nowadays. The set of these researches is concerned with old people and lack of infrastructures of reception for those who are at risk or tend to have deterioration in their health condition. Thus, several works of research contributed to develop telemedicine services. They notably focus on the conception and the development of communication architectures between the actors of these systems, monitoring and the development of human??s quality is based on the storage of the collected data at home and analytical tools, and processing of these large quantities of data. Therefore, it is useful to detect and prevent the occurrence of critical situations of a remote person, the transmission of the messages and alarms to concerned actors to be ready to intervene in a case of emergency. Many works and systems undertaken in this field carry out the complete analysis and synthesis of signals on large servers (great capacities, better resolutions??). Moreover, these systems would have required large means and a large infrastructure in their deployment (installation, configuration??), which generates the disadvantage of the excessive expenditure. In this paper, we suggest to introduce and implement this complete treatment for revealing critical situations and pathologies on a simple mobile phone by respecting theirs constraints. The principal objective is to permit a taking off for medical and social dependant people as aged ones, handicapped, in order to the adaptation with their environment domestically and make up their incapacities. In this case, it is indispensable to make a diagnostic in a real time and well manage the patient??s computerized data between the various medical actors with the permanent security insurance of highly risky patients. Furthermore, the need to make a speed diagnostic of patients and to detect their health state, their parameters (medical information) of analyses with efficacy, allows us to gain time while monitoring the cardiac patient. It concerns the implementation of services on mobile terminals for transferring medical information and results of ECG analysis (calculated parameters) in a real time with ensuring the mobility, the permanent security and the reliability insurance in covered zone by the mobile network, PLMN (GSM/GPRS??). Our attention has been focused on the choice of a relevant work. It concerns an application on a mobile terminal (MIDlet) for detecting some cardiac pathologies and monitoring patient in a non-hospital setting. This paper recalls a complete architecture of an economic wireless transmission system with the implementation of an effective algorithm, adapted to the mobile terminal, allowing to the doctor to have the results of the ECG analysis. Thus, the stakes of setting up such systems are numerous, so much for patients, medical staff and the society in general.