Journal 2011

INTERNATIONAL JOURNAL 

A COMPARATIVE STUDY ON HARDWARE PLATFORMS FOR

WIRELESS SENSOR NETWORKS

Vũ Chiến Thắng, Nguyễn Chấn Hùng

Nguyễn Hữu Thanh

 Abstract: Recently, Wireless Sensor Networks (WSNs) attract a great deal of research attention, and are envisioned to support a variety of applications, including building monitoring, environment control, wild-life habitat monitoring, forest fire detection, industry automation, military, security, and health-care. Over the years, we have seen a variety of hardware platforms for WSNs to facilitate developing WSN applications. In this paper, we provide a comprehensive review of existing hardware platforms for WSNs. We first present the hardware architecture of a wireless sensor node. We then survey the major hardware platforms for WSNs and present a comparison of these hardware platforms. Finally we present some recommendations from the perspectives of hardware platform developers and hardware platform users. The authors hope that making information about existing hardware platforms will assist researchers working in this area to appreciate the diversity of platforms available to them and to help them select the most appropriate platform for their purposes

International journal on Advanced Science Engineering

Information Technology Tr 70-74, 2011

A Novel Spectral conversion based Approach for Noisy Speech Enhancement

Đỗ Huy Khôi, Phùng Trung Nghĩa, Nguyễn Hữu Công

Nguyễn Văn Tảo, Thái Quang Vinh

 Abstract: Present noisy speech enhancements algorithms are efficiently used for additive noise but not very good for convolutive noise as reverberation. And even for additive noise, the estimation of noise, when only one microphone source is provided, is based on the assumption of a slowly varying noise environment, commonly assumed as stationary noise. However, real noise is non-stationary noise, which difficult to be efficiently estimated. Spectral conversion can be used for predicting the vocal tract (spectral envelope) parameters of noisy speech without estimating the parameters of the noise source. Therefore, it can be applied to a general speech enhancement model, for both stationary and non-stationary additive noise environment, as well as convolutive noise environment, when only one microphone source is provided. In this paper, we propose a spectral conversion based speech enhancement method. The experimental results show that our method outperforms traditional methods.

International Journal of Information and Electronics Engineering Tr 281-285, 2011

AN IMPLICIT ITERATION METHOD FOR VARIATIONAL INEQUALITIES OVER THE SET OF COMMON FIXED POINTS FOR A FINITE FAMILY OF NONEXPANSIVE MAPPINGS IN HILBERT SPACES

Nguyễn Bường, Nguyễn Thị Quỳnh Anh

 Abstract: We introduce a new implicit iteration method for finding a solution for a variational inequality involving Lipschitz continuous and strongly monotone mapping over the set of common fixed points for a finite family of nonexpansive mappings on Hilbert spaces. Fixed Point Theory and Applications Volume 2011 (2011), Article ID 276859, 10 pages, doi:10.1155/2011/276859,2011

 

ON THE OPTIMAL SHAPE PARAMETER FOR GAUSSIAN RADIAL BASIS FUNCTION FINITE DIFFERENCE APPROXIMATION OF THE POISSON EQUATION. COMPUT. MATH. APPL.,

Oleg Davydov, Đặng Thị Oanh

 Abstract: We investigate the influence of the shape parameter in the meshless Gaussian RBF finite difference method with irregular centres on the quality of the approximation of the Dirichlet problem for the Poisson equation with smooth solution. Numerical experiments show that the optimal shape parameter strongly depends on the problem, but insignificantly on the density of the centres. Therefore, we suggest a multilevel algorithm that effectively finds near-optimal shape parameter, which helps to significantly reduce the error. Comparison to the finite element method and to the generalised finite differences obtained in the flat limits of the Gaussian RBF is provided.

Computers and Mathematics with Applications 62(2011)

 

ADAPTIVE MESHLESS CENTRES AND RBF STENCILS

 FOR POISSON EQUATION

Oleg Davydov, Đặng Thị Oanh

 Abstract: We consider adaptive meshless discretisation of the Dirichlet problem for Poisson equation based on numerical differentiation stencils obtained with the help of radial basis functions. New meshless stencil selection and adaptive refinement algorithms are proposed in 2D. Numerical experiments show that the accuracy of the solution is comparable with, and often better than that achieved by the mesh-based adaptive finite element method.

Journal of Computational Physics. (Trong danh muc ISI) 230(2011)

 

FAST HASH FUNCTIONS BASED ON CONTROLLED PERMUTATIONS

Đỗ Thị Bắc, Hồ Ngọc Duy

 Abstract: Using variable bit permutations there are designed hash functions prossessing high performance while hardware, firmware, and software implementation. Controlled bit permutation operation have been selected in correspondence with earlier proposed topology of the permutation network for implementing on its base the controlled bit permutation in struction oriented to embedding in the mass microprocessors. Due to the last fact the designed algorithms for computing cryptographic checksums are perspective for application as fast software-suitable hash function.

Вопросы защиты информации. 2, 2-6, 2010.

 

INTERNATIONAL PROCEEDING

 IMPLEMENTING UN-IDENTIFIELD COMMUNICATION IN

UBIQUITOUS PHONE SYSTEM

Nguyễn Thị Lan Anh, Bongkyo-Moon

 Abstract: Context awareness plays an important role in Ubiquitous applications based on the context information to provide services adapting to users’ needs. The advantages of some context-aware smart phone systems, including iCAM[1], contextPhone[2], Live Contact Project [3], Enhanced Telephony[4] and Ubiquitous phone System Ubiphone [5] show themselves to be typical examples of Ubiquitous service ones. Using a context-aware smart phone, we can contact individuals in many ways, including by home, office, or cell phone, short message service (SMS), instance message(IM), and email. Therefore, a human-centered smart phone could discover how best to reach a contact at any given moment. However, in these systems, the users can contact to people in the contact list only, and the context information is managed and referred on only one ontology tree in one domain which contraries to the reality that in Ubiquitous environment. In this environment, the context information such as concepts and relationships are also managed and referred on heterogeneous ontology in several domains, which drive new challenges in the discovery of knowledge sources relevant to a users’ request. New efficient technique and approach for developing and extending Ubiquitous phone intelligence is presented in this paper, which combines agent-based technologies and Artificial Neural Networks (ANNs) models to match ontology, helping users search and contact with anyone outside the contact list satisfying the users’ requests even there is no social relationship between them.

The 2011 International conference on Advanced Technologies for Communications Tr 174-178, 2-4/08/2011

A COMPARATIVE STUDY ON OPERATING SYSTEM FOR

 WIRELESS SENSOR NETWORKS

Vũ Chiến Thắng, Nguyễn Chấn Hùng, Nguyễn Hữu Thanh

 Abstract: Wireless Sensor Networks (WSNs) have been the subject of intensive research over the last years. WSNs consist of a large number of sensor nodes, and are used for various applications such as building monitoring, environment control, wild-life habitat monitoring, forest fire detection, industry automation, military, security, and healthcare. Operating system (OS) support for WSNs plays a central role in building scalable distributed applications that are efficient and reliable. Over the years, we have seen a variety of operating systems (OSes) emerging in the sensor network community to facilitate developing WSN applications. In this paper, we present OS for WSNs. We begin by presenting the major issues for the design of OS for WSNs. Then, we examine some existing OSes for WSNs, including TinyOS, Contiki, and LiteOS. Finally, we present a comparison of these OSes by examining some important OS features. We believe that our work will help both OS developers and OS users. With OS developers, they will know what has worked in previous OSes and what has not. With OS users, they know the features of existing sensor network OSes, so they can select a sensor network OS that is the most appropriate for their application.

International Conference on Advanced Computer Science

and Information System 2011. Tr 73-78,2011

 

A SPECTRAL CONVERSION BASED SINGLE – CHANNEL SINGLE – MICROPHONE SPEECH ENHANCEMENT

Đỗ Huy Khôi, Thai Quang Vinh

 Abstract: Most of present single microphone speech enhancement algorithms are efficiently used for additive noise but not very good for convolutive noise as reverberation. And even for additive noise, the estimation of noise, when only one microphone source is provided, is based on the assumption of a slowly varying noise environment, commonly assumed as stationary noise. However, real noise is non-stationary noise, which difficult to be efficiently estimated. Spectral conversion can be used for predicting the vocal tract (spectral envelope) parameters of noisy speech without estimating the parameters of the noise source. Therefore, it can be applied to a general speech enhancement model, for both stationary and non-stationary additive noise environment, as well as convolutive noise environment, when only one microphone source is provided. In this paper, we propose a spectral conversion based speech enhancement method. The experimental results show that our method is a promising method and need to be further studied. 

Proceedings of the 4th  international conference on computer and electrical engineering( ICCEE 2011), Tr 583-591, 2011.