New methods for better identification of timber geographical origin would constitute an important technical element in the forest industry, for phytosanitary certification procedures or in the chain of custody developed for the certification of timber from sustainably managed forests. In the case of the European white oaks, a detailed reference map of chloroplast (cp) DNA variation across the range exists, and we propose here to use the strong geographical structure, characterized by a differentiation of western vs. eastern populations, for the purpose of oak wood traceability. We first developed cpDNA markers permitting the characterization of haplotype on degraded DNA obtained from wood samples. The techniques were subsequently validated by confirming the full correspondence between genotypes obtained from living tissues (buds) and from wood collected from the same individual oak. Finally, a statistical procedure was used to test if the haplotype composition of a lot of wood samples is consistent with its presumed geographical origin. Clearly, the technique cannot permit the unambiguous identification of wood products of unknown origin but can be used to check the conformity of genetic composition of wood samples with the region of alleged origin. This could lead to major applications not only in the forest industry but also in archaeology or in palaeobotany.

[1] Array processing usually operates on identical sensors. In this paper an investigation is made to apply the direction finding algorithm MUSIC to an antenna array with nonidentical elements (heterogeneous array). This original solution is polarizationsensitive though it resorts to only one sensor at each point of the spatial sampling. As a major consequence of its structure, the computation of the MUSIC algorithm is based on an expression of the steering vector that integrates the spatial response of each sensor. This concept is then validated in the special context of HF radio direction finding, for which a deterministic model of the polarization at the exit of the ionospheric channel is derived. A multichannel radio receiving system has been developed and experimented using transmitters located more than 1000 km from the receiving site.

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[1] The concept of multiple input multiple output (MIMO) has become a productive area of research in the field of wireless communications with the aim of delivering increased data throughput. However, to date, MIMO research has focused primarily on short-range communications within the VHF, UHF, and SHF bands, and very little research has been conducted toward exploiting MIMO techniques for long-range communications within the HF band. Between September 2007 and September 2008, several experimental campaigns were conducted to investigate the feasibility of applying MIMO techniques within the HF band. The results of measurements over a 255 km path from Durham to Leicester within the United Kingdom are presented in this paper with particular emphasis on the use of heterogeneous antenna arrays at the transmitter and receiver.

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[1] Atmospheric noise, originating essentially from lightning discharges, is the main disturbance of VLF/LF telecommunications. This paper characterizes atmospheric noise in the 10-80 kHz range and proposes a new model: very accurate low-frequency noise model (VALERIE). This model uses a new approach, which combines noise measurements with lightning data. The noise statistics were obtained from several years of measurements taken by the Délégation Générale de l'Armement (DGA)/Centre Technique des Systèmes Naval (CTSN) (Toulon, France) and the Space and Naval Warfare Systems (SPAWAR) (San Diego, California). Lightning data were provided by recent satellite observations made by NASA. A comparison of VALERIE predictions with measurements by cross validation showed an increase in accuracy compared to the current International Telecommunication Union (Geneva) model and a decreased average deviation. The model has been validated for the Atlantic area but may be extended as new measurements are collected.

EEKTEL Louis, MARIE Franqois 1. S.R./I..K. UPKES-A CNRS 6075 Universite de Rennes I 35042 KENNES-Ccdex FRANCE I INTRODUCTIONThis paper presents an original method of direction finding operating on an array of collocated antennas. At first. we derive the classical MUSIC algorithm for an heterogeneous array, i.e. made up of different sensors : their complex directional responses, which are supposed to be well known, arc integrated in the normalized steering-vectors. We underline the advantages induced by this technique in the field of radio direction finding. specially as two types of polarization are received (right or left circular polarization in the V.H.F range, ordinary or cxuaordinary polarization in the H.F. range). Then. we show that the diversity of the sensors c m replace to some extent the space diversity usually provided by classical arrays. Actually. the array manifold does not only depend on the geometry but also on the directivity functions of the sensors. In those conditions, it becomes feasible to find the directions of arrival with a small array aperture. and possibly with collwated sensors. At last. we present experimental validations in the H.F.(3-30MHz) range. II MUSIC A1,GORITHM OPERATING ON AN ARRAY OF IDENTICAL SENSORSThe parametric inclhods aim lo estimate parameters which are bound to the incident sources such as angles of arrival, power ... by the computation of P directional function from the steering vector of the may. For a sourcc which direction of arrival is denoted 6 (angle or couple of angles in a 3-D problem), this vector is written as F(6) is the common directional response of the NC sensors (supposed to be identical) and %(e) is the geometrical phase of sensor k (sensor I being chosen as a reference).The MUSIC algorithm is based on the orthogonality of the incident steering-vectors and the noise subspace of the datii covarimce inabix : the computation of the pseudo-spectrum uses the norm of the projection of the normalized slecring-vector b(6) = in that subspace: la(g)Iwhere the set of vectors Vk delinc the noise suhspace.As shown below, the pseudo-spectrum PSSP(9) can be computed without the knowledge of the sensor responses F(6) :where biso (0) is the normalized stcering-vector for an array of iaotropic sensors and -Further on, 0-7803-4478-2/98/$10.00 0 1998 IEEE 207