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Height estimation of scatterers in complex environments via the Tomographic Synthetic Aperture Radar (TomoSAR) technique is still a valuable research field. The parametric spectral estimation approach constitutes a powerful tool to identify the superimposed scatterers with different complex reflectivities, located at different heights in the same range–azimuth resolution cell. Unfortunately, this approach requires prior knowledge about the number of scatterers for each pixel, which is not possible in practical situations. In this paper, we propose a method that analyzes the scree plot, generated from the spectral decomposition of the multidimensional covariance matrix, in order to estimate automatically the number of scatterers for each resolution cell. In this context, a properly improved regularization step is included during the reconstruction process, transforming the parametric MUSIC estimator into a non-parametric method. The experimental results on two data sets covering high elevation towers, with different facade coating characteristics, acquired by the TerraSAR-X satellite highlighted the effectiveness of the proposed regularized MUSIC for the reconstruction of high man-made structures compared with classical approaches.

This article provides a cross-sectional overview of the evolution of music teaching methods over a 160-year timeline. The objective of the study is limited to examining the mainstream trends in the development of methods, or their manifestations, as well as discussing the causes behind them. The objective is also to investigate the methodical state of the 21st century teaching. The data consists of previous studies, music textbooks and learning diaries of class teacher students (N=79). The analysis of the data is based on analytic-historical and data-driven content analysis. The time period from 1860 to1970 has focused on developing the methods. The participatory and functional methods have remained dominant for the longest time. As we enter the 1980s, methods are gradually being phased out and they are used only occasionally, or the main focus is not on them anymore. As a result, teaching methods are fragmented and their implementations depend on the teacher's pedagogical skills in music teaching. peerReviewed

無線通信環境では，電波は建物やビル，障害物や壁により反射や回折，散乱を起こし，複数の異なった伝搬経路，マルチパスを経て受信点に到達する．このマルチパス環境では電波は互いに複雑に干渉し合い，電波の伝搬特性は空間的に大きく変動する．これは伝搬特性の局所性と呼ばれ，その局所性の範囲を超えた地点，つまり受信点からフェージングの相関距離以上離れた地点のフェージング変動は，基準となる受信点のものとは異なるものになる．先行研究において，このフェージングの相関距離以上離れた地点の伝搬特性を推定する他地点伝搬特性推定方式が検討されている．この手法では，マルチパス環境の各素波が平面波であるという前提のもとに，MUSIC法による到来方向推定と最小二乗法による複素振幅推定を用いて到来波環境を分析し，基準点から推定対象点までの位相差を考慮してマルチパスを合成することにより伝搬特性を推定している．この推定方式の2次元環境における基本的な推定特性は検討が進められているが，実際の環境である3次元環境に適応した方式はまだ確立されていない．よって本稿では，平面アレーアンテナを用いて3次元環境に適応させた新たな他地点伝搬特性推定法の検討を行う．, In a wireless communication environment, radio waves are reflected, diffracted and scattered by buildings and obstacles. Because radio waves propagate through the environment, mutual interference of the radio waves occurs and radio propagation properties, such as the amplitude and the phase of the received signal, vary significantly. It is called multipath fading. In addition, radio propagation properties fluctuate widely and spatially. In other words, the propagation properties are local information which can be obtained only at a certain location. In general, we cannot estimate the propagation properties at a remote location over the locality range of the multipath fading. Therefore we study a method to estimate the radio propagation properties at a remote location from a receiving point. An estimation method for such purpose has been studied. In the method, the multipath environment is analyzed by estimating the directions of arrival (DOAs) by the Multiple Signal Classification (MUSIC) method and the complex amplitudes by the least square method, respectively. Using the estimated DOAs and the complex amplitudes of the arriving waves, the propagation properties at the target point are estimated based on the plane wave assumption for each arriving wave. The estimation method has so far been studied assuming a 2-dimensional space. However, an estimation method of a 3-dimensional space has not been yet established. This paper discusses a new estimation method for adapting the method to a 3-dimensional space by using a planar array antenna.

In order to improve resolution and direction of arrival (DOA) estimation of two closely spaced sources, in context of array processing, a new algorithm is presented. However, the proposed algorithm combines both spatial sampling technic to widen the resolution and a high resolution method which is the Multiple Signal Classification (MUSIC) to estimate the DOA of two closely spaced sources impinging on the far-field of Uniform Linear Array (ULA). Simulations examples are discussed to demonstrate the performance and the effectiveness of the proposed approach (referred as Spatial sampling MUSIC SS-MUSIC) compared to the classical MUSIC method when it’s used alone in this context.

Za sprovođenje savremenih operacija, kako na operativno-strategijskom, tako i na taktič kom nivou, izuzetno je važno da se obezbedi kontinuirani nadzor vazdušnog prostora. Poznato je da su aktivni radarski sistemi, na kojima se kod nas trenutno zasniva nadzor vazdušnog prostora, u ratnim uslovima veoma ranjivi i podložni elektronskim i borbenim dejstvima protivnika, što je u toku rata 1999. godine i praktično potvrđeno. Kao alternativa aktivnim radarskim sistemima nameće se koncept pasivnog nadzora vazdušnog prostora korišćenjem distribuiranih multisenzorskih sistema. Predmet širih istraživanja predstavljaju tehnička rešenja integrisanog multisenzorskog sistema za pasivan nadzor vazdušnog prostora, koji se sastoji od sledećih podsistema za nadzor vazdušnog prostora: na radio-gonimetarskom principu u frekvencijskom opsegu 20-3000 MHz, na zvukometrijskom principu, na principu vizuelnih osmatračkih stanica, na termovizijskom i televizijskom principu. U ovom radu analizirani su opšti principi pasivnog nadzora vazdušnog prostora multisenzorskim sistemima i predložena je tehnička koncepcija radio-goniometarskog i zvukometrijskog podsistema. / It is very important to provide continuous air surveillance in to realize modern operations on the operational-strategic level and tactical, as well. It is well known that active radar systems, on which air surveillance is based in our country, are very vulnerable in war times and susceptible to the electronic counter and combat attacks of the enemy, what is shown practically in 1999 war. Air surveillance by passive multi-sensor systems is a possible alternative to the air surveillance by the active radar systems. Subjects of our wider research are technical solutions of integrated multi-sensor systems for passive air surveillance which consists of the following subsystems: a subsystem for the air communication intelligence within the frequency range 20-3000 MHz based on intercept/direction finding principle, a subsystem for the air surveillance based on the acoustic intelligence, a subsystem for the air surveillance based on the station for the visual intelligence, a subsystem for air surveillance based on thermo-vision and television principle. General principles of air surveillance are presented, and the concepts of the subsystems for the air communication intelligence and acoustic intelligence are proposed in this paper.

U ovom radu je, polazeći od opštih principa izviđanja radio-komunikacija analiziran problem izviđanja radio-komunikacija u VF opsegu 1,6-30 MHz na operativno-strategijskom nivou koje se sprovodi u funkciji obaveštajnog obezbeđenja. Izložen je koncept širokopojasnog multifunkcionalnog radio-goniometra u kojem su integrisane funkcije automatskog presretanja i goniometrisanja signala, koji treba da omogući trenutni i potpuni nadzor (otkrivanje i goniometrisanje) svih aktivnih emisija u kompletnom VF frekvencijskom opsegu koje nisu kraće od 10 ms. Ovaj goniometar predstavlja osnovicu budućeg automatizovanog radioizviđačkog sistema za VF opseg, koji sistemu komandovanja savremenim operacijama treba da omogući potpuni uvid u stanje, odnosno praćenje aktivnosti radio-komunikacija u kompletnom VF opsegu, što postojeći sistem za izviđanje VF frekvencijskog opsega ne obezbeđuje. Izložena problematika zasniva se na analizi iskustava i trendova u ovoj oblasti u svetu, na iskustvima stečenim u VTI kroz dosadašnje istraživačke i razvojne zadatke, posebno kroz razvoj i terenska ispitivanja radio-goniometra za VVF/UVF opseg. / Starting from the elaboration of the basic principles of communication intelligence, a problem of communication intelligence in HF range 1,6-30 MHz on the operational-strategic level is analyzed in detail. A concept of the wide-band multifunctional direction finder with integrated intercept and direction finding functions is presented. The direction finder should provide complete surveillance of the HF range and interception with direction finding of all active signals in given frequency range which are not shorter than 10 ms. The direction finder is the key element of the future automated radio reconnaissance system for the HF range, that should provide a complete insight of the signal activities in the HF range, which the existing communication intelligence system does not provide. The subject matter of this paper is based on the analysis of experiences and current trends in this field in the world, on experiences gained in VTI in previous research and development projects, especially in development and testing of the prototype of the direction finder fot the VHF/UHF frequency range.

The goal of the paper is to use the MUSIC method to estimate the fundamental frequency of signals, and compare the results with the ones obtained by the DFT method. Real speech signals are considered in the paper. Lithuanian vowel sound fundamental frequency is estimated by the MUSIC and DFT methods.