Rene Ndoundam

Rene Ndoundam
University of Yaounde I | UY1 · Faculty of Sciences

Doctorat d'Etat in Computer Science

About

36
Publications
3,791
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117
Citations
Introduction

Publications

Publications (36)
Preprint
In this paper, we proposed a method that exploits justified texts of PDF files to embed secret data. The method is inspired by the work of Khosravi et al on "A new method for pdf steganography in justified texts" where they proposed a stegosystem allowing to embed in particular lines called a host line, 4 bits of secret message. We've improved it b...
Preprint
In this paper, we proposed a method that exploits justified texts of PDF files to embed secret data. The method is inspired by the work of Khosravi et al on "A new method for pdf steganography in justified texts" where they proposed a stegosystem allowing to embed in particular lines called a host line, 4 bits of secret message. We've improved it b...
Article
Full-text available
Community discovery in networks is one of the most popular topics of modern network science. Given the spread of social networks extracted from applications data, it would be important to recognize that the study of communities in multidimensional networks is becoming a major issue since many individuals can maintain several types of relationships...
Article
Full-text available
Distributed steganography is an approach to concealing the secret in several files, leaving fewer traces than the classical approach. Recent work proposed by Moyou and Ndoumdan have improved this approach by preserving the integrity of these files in a multi-cloud storage environment. However, the approach requires a large size of the stego-key and...
Article
The IEEE 802.11p standard has been amended in the 5.9GHz band in 2010 to provide road safety by enabling vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. V2V communications evolve the exchange of Wave Short Messages (WSM) between vehicles for safety advertisement, either in one hop or multi-hop broadcasts. However, previ...
Preprint
Information has always constituted a prized commodity over time, with the strong globalization of exchanges and communications. The provenance, acquisition, protection and integrity of information has always asked major questions, with the strong growth of security needs in many areas around the world. Numerous approaches have been proposed with a...
Preprint
Full-text available
We propose a steganographic scheme based on permutations, which improves the capacity of embedding information in a series of p host binary images. Given a host binary image block of size m x n bits and any embedding technique T, where T can hide Q(m, n) bits of data in the image; given p images, T can hide p x Q(m, n) bits of data in these images....
Article
Full-text available
Classical or traditional steganography aims at hiding a secret in cover media such as text, image, audio, video or even in network protocols. Recent research has improved this approach called distributed steganography by fragmenting the secret message and embedding each secret piece into a distinct cover media. The major interest of this approach i...
Article
Community detection in directed networks appears as one of the most relevant topics in the field of network analysis. One of the common themes in its formalizations is information flow clustering in a network. Such clusters can be extracted by using triads, expected to play an important role in the detection of that type of communities since commun...
Preprint
Full-text available
In this paper, we propose a text steganographic scheme based on color coding and permutation. Given a secret message and a cover text, the proposed scheme embed the secret message in the cover text by making it colored, using a permutation algorithm. The stego-text is then send to the receiver by mail. The results which have been obtained by experi...
Article
Full-text available
Vehicular Ad hoc NETworks (VANETs) help in improving road traffic safety and efficiency. In V2V communications, vehicles exchange kinematic information over a suitable protocol in order, either to warn other vehicles of a dangerous situation or inform them about the current status of the traffic flow. When using Wireless Access in Vehicular Environ...
Article
Full-text available
Among natural disasters observed each year, flood represents 40% and remains one of the most important problems that many governments want to solve. Each year flood is responsible for many damages that cost a lot of money and even lot of people's life. To reduce these damages caused, flood forecasting and warning systems which are able to alert peo...
Article
Full-text available
Within the last decade, several approaches using quaternion numbers to handle and model multiband images in a holistic manner were introduced. The quaternion Fourier transform can be efficiently used to model texture in multidimensional data such as color images. For practical application, multispectral satellite data appear as a primary source for...
Article
Testing involves approximately 60% of the cost of software development, and includes the validation of reports, which plays an important role in decision-making in companies. Automatic report testing includes testing the content and the layout of the report. The conventional method used in testing reports leads to a development time of test cases b...
Article
Full-text available
We propose a new model of steganography based on a list of pseudo-randomly sorted sequences of characters. Given a list $L$ of $m$ columns containing $n$ distinct strings each, with low or no semantic relationship between columns taken two by two, and a secret message $s \in \{0,1\}^*$, our model embeds $s$ in $L$ block by block, by generating, for...
Article
We characterize the structure of the periods of a neuronal recurrence equation. First, we give a characterization of k-chains in 0-1 periodic sequences. Second, we characterize the periods of all cycles of some neuronal recurrence equation. Third, we explain how these results can be used to deduce the existence of the generalized period-halving bif...
Article
Full-text available
Informally, steganography is the process of exchanging a secret message between two communicating entities so that an eavesdropper may not know that a message has been sent. After a review of some steganographic systems, we found that these systems have some defects. First, there are situations in which some concealment algorithms do not properly h...
Article
We propose different approaches of PDF files based steganography, essentially based on the Chinese Remainder Theorem. Here, after a cover PDF document has been released from unnecessary A0, a secret message is hidden in it using one of the proposed approaches, making it invisible to common PDF readers, and the file is then transmitted through a non...
Article
Full-text available
Infection with the hepatitis C virus (HCV) is the most common coinfection in people with the human immunodeficiency virus (HIV), and hepatitis C is categorized as an HIV related illness. The study of the joint dynamics of HIV and HCV present formidable mathematical challenges in spite the fact that they share similar routes of transmission. A deter...
Article
Full-text available
We study the sequences generated by neuronal recurrence equations of the form $x(n) = {\bf 1}[\sum_{j=1}^{h} a_{j} x(n-j)- \theta]$. From a neuronal recurrence equation of memory size $h$ which describes a cycle of length $\rho(m) \times lcm(p_0, p_1,..., p_{-1+\rho(m)})$, we construct a set of $\rho(m)$ neuronal recurrence equations whose dynamics...
Article
cryptographic hash function is a deterministic procedure that compresses an arbitrary block of numerical data and returns a fixed-size bit string. There exist many hash functions: MD5, HAVAL, SHA, ... It was reported that these hash functions are not longer secure. Our work is focused in the construction of a new hash function based on composition...
Article
Full-text available
We propose a hash function based on arithmetic coding and public-key cryptography. The resistance of the hash function to second preimage attack, collision and differential cryptanalysis is based on the properties of arithmetic coding as a non-linear dynamical system. The resistance of the hash function to first preimage attack is based on the publ...
Article
We present an online algorithm for routing the automorphisms (BPC permutations) of the queueless MIMD hypercube. The routing algorithm has the virtue of being executed by each node of the hypercube without knowing the state of the others nodes. The algorithm is also vertex and link-contention free. We show, using the proposed algorithm, that BPC pe...
Article
Full-text available
We study the cycles generated by the chip firing game associated with n-cube orientations. We show the existence of the cycles generated by parallel evolutions of even lengths from 2 to $2^n$ on $H_n$ (n >= 1), and of odd lengths different from 3 and ranging from 1 to $2^{n-1}-1$ on $H_n$ (n >= 4).
Article
In this paper, we study the convergence of a mathematical model of opinion dynamics called the majority model. In this model, at each iteration step, each individual adopts the opinion which exerts on him the maximum social pressure. Under some assumptions on interaction among members of the society, we show that, in parallel mode, attractors of th...
Article
Full-text available
In this paper, we study memory iteration where the updating considers a longer history of each site and the set of interaction matrices is quasi-palindromic. For parallel and sequential iterations with memory, we define Lyapunov functional which permits us to characterize the periods behaviour and explicitly bounds the transient lengths of quasi-pa...
Article
Full-text available
We exhibit a family of neural networks of McCulloch and Pitts of size $2nk+2$ which can be simulated by a neural networks of Caianiello of size $2n+2$ and memory length $k$. This simulation allows us to find again one of the result of the following article: [Cycles exponentiels des r\'{e}seaux de Caianiello et compteurs en arithm\'{e}tique redondan...
Article
Full-text available
We study memory iteration where the updating consider a longer history of each site and the set of interaction matrices is palindromic. We analyze two different ways of updating the net-works: parallel iteration with memory and sequential iteration with memory that we introduce in this paper. For parallel iteration, we define Lyapunov functional wh...
Conference Paper
Full-text available
We study the cycles generated by the chip firing game associated with n-cube orientations. We consider a particular class of partitions of vertices of n-cubes called left cyclic partitions that induce parallel periodic evolutions. Using this combinatorical model, we show that cycles generated by parallel evolutions are of even lengths from 2 to 2n...
Article
Full-text available
The sequences generated by a neuronal recurrence equation with memory of the form x(n) 1[ h i1 a i x(n i) Θ], where h is the size of the memory, are studied. It is shown that in the case where all the parameters (a i) 1ih are positive reals, there exists a neuronal recurrence equation of memory length h that generates a sequence of period (e 3 h(ln...
Article
We study the sequences generated by neuronal recurrence equations of the form x(n)=1[∑j=1kajx(n−j)−θ], where k is the size of memory (k represents the number of previous states x(n−1),x(n−2),…,x(n−k) which intervene in the calculation of x(n)). We are interested in the number of steps (transient length) from an initial configuration to the cycle, w...
Article
We study the sequences generated by a neuronal equation with memory of the form x n 1[ k i1 a i x ni Θ], where k is the size of the memory. We show that in the case where all the parameters (a i) 1ik are negative real numbers, there exists a neuronal equation of memory length k that generates a sequence of period e (k log k) . This result shows tha...
Article
In this paper we study the sequences generated by a neuronal equation of the form x n =1[∑ i=1 k a i x n-i -θ], where k is the size of the memory. We show that in the case where all the parameters (a i ) 1≤i≤k are strictly positive reals and k is a multiple of 6 (i.e., k=6m), there exists a subset B={ω 1 ,ω 2 ,⋯,ω α } of {1,2,⋯,m-1} and for which t...
Article
The following (solitaire) game is considered: Initially each node of a simple, connected, finite graph contains a finite number of chips. A move consists in firing all nodes with at least as many chips as their degree, where firing a node corresponds to sending one of the node's chips to each one of the node's neighbors. In [Bi89] it was conjecture...
Article
Nous étudions le comportement dynamique d'un réseau d'automates introduit dans la littérature sous le nom de "chip firing game" et qui intervient dans la modélisation de certains phénomènes physiques tels que des systèmes de balles qui rebondissent sur des parois mobiles en leur faisant subir des mouvements de translation. Nous nous intéressons au...

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Projects

Projects (2)
Project
The aim is to increase the embbedibg capacity of the text-stego systems.
Project
researchThe Pagirn-PPTIC is a regional project. • The objectives are: - improve the planning and implementation of digital integration infrastructure in Central African countries; - improve the decision-making of the authorities on the basis of updated ICT information; • Target groups are: populations, businesses, ICT operators, ICT regulators, governments, civil society and NGOs, sub-regional institutions, international institutions; • Final beneficiaries are users in urban and rural areas, companies, ICT operators; • Expected products are: ICT needs mapping, regional and national strategic plans, people trained in governance and ICT planning, ICT Regional Observatory; • The places of action are: Cameroon, Central African Republic, Congo, Gabon, Democratic Republic of Congo, Chad.