STABILITY, FINITE-TIME STABILITY AND PASSIVITY CRITERIA FOR DISCRETE-TIME DELAYED NEURAL NETWORKS

In this paper, we present the problem of stability, finite-time stability and passivity for discrete-time neural networks (DNNs) with variable delays. For the purposes of stability analysis, an augmented Lyapunov-Krasovskii functional (LKF) with single and double summation terms and several augmented vectors is proposed by decomposing the time-delay interval into two non-equidistant subintervals. Then, by using the Wirtinger-based inequality, reciprocally and extended reciprocally convex combination lemmas, tight estimations for sum terms in the forward difference of LKF are given. In order to relax the existing results, several zero equalities are introduced and stability criteria are proposed in terms of linear matrix inequalities (LMIs). The main objective for the finite-time stability and passivity analysis is how to effectively evaluate the finite-time passivity conditions for DNNs. To achieve this, some weighted summation inequalities are proposed for application to a finite-sum term appearing in the forward difference of LKF, which helps to ensure that the considered delayed DNN is passive. The derived passivity criteria are presented in terms of linear matrix inequalities. Some numerical examples are presented to illustrate the proposed methodology

Delay-dependent stability analysis for discrete-time systems with time varying state delay

The stability of discrete systems with time-varying delay is considered. Some sufficient delaydependent stability conditions are derived using an appropriate model transformation of the original system. The criteria are presented in the form of LMI, which are dependent on the minimum and maximum delay bounds. It is shown that the stability criteria are approximately the same conservative as the existing ones, but have much simpler mathematical form. The numerical example is presented to illustrate the applicability of the developed results

Simple stability conditions of linear discrete time systems with multiple delay

In this paper we have established a new Lyapunov-Krasovskii method for linear discrete time systems with multiple time delay. Based on this method, two sufficient conditions for delay-independent asymptotic stability of the linear discrete time systems with multiple delays are derived in the shape of Lyapunov inequality. Numerical examples are presented to demonstrate the applicability of the present approach

OPTIMAL BATTERY STORAGE LOCATION AND CONTROL IN DISTRIBUTION NETWORK

The paper discusses the problem of the energy losses reduction in electrical networks using a battery energy storage system. One of the main research interests is to define the optimal battery location and control, for the given battery characteristics (battery size, maximum charge / discharge power, discharge depth, etc.), network configuration, network load, and daily load diagram. Battery management involves determining the state of the battery over one period (whether charging or discharging) and with what power it operates. Optimization techniques were used, which were applied to the model described in the paper. The model consists of a fitness function and a constraint. The fitness function is the dependence of the power losses in the network on the current battery power, and it is suggested that the function be fit by a n - order power function. The constraints apply to the very characteristics of the battery for storing electricity. At any time interval, the maximum power that the battery can receive or inject must be met. At any time, the stored energy in the battery must not exceed certain limits. The power of losses in the network is represented as the power of injection into the nodes of the network. The optimization problem was successfully solved by applying a genetic algorithm (GA), when determining optimal battery management. Finally, the optimal battery management algorithm is implemented on the test network. The results of the simulations are presented and discussed

FINITE-TIME STABILITY ANALYSIS OF DISCRETE TIME-DELAY SYSTEMS USING DISCRETE CONVOLUTION OF DELAYED STATES

Finite-time stability for the linear discrete-time system with state delay was investigated in this article. Stability of the system was analyzed using both the Lyapunov-like approach and the discrete Jensen’s inequality. A novel Lyapunov-like functional with a discrete convolution of delayed states was proposed and used for the derivation of the sufficient stability conditions of the investigated system. As a result, the novel stability conditions guarantee that the states of the systems do not exceed the predefined boundaries on a finite time interval. The proposed methodology was illustrated with a numerical example. A computer simulation was performed for the analysis of the dynamical behavior of this system

Dostignuća u oplemenjivanju NS hibrida uljane repice

The increased production of oilseed rape (Brassica napus L.) is evident on a global scale, but also in Serbia in the last decade. Rapeseed is used primarily for vegetable oil and processing industry, but also as a source of protein for animal feed and green manure. Following the cultivation of varieties, breeding and cultivation of hybrid rapeseed started in the 1990's, to take advantage of heterosis in F1 generation, while protecting the breeder's rights during seed commercialization. The breeding of hybrid oilseed rape requires high quality starting material (lines with good combining abilities) for introduction of male sterility. Ogura sterility system is primarily used at the Institute of Field and Vegetable Crops, Novi Sad, Serbia. To use this system, separate lines are modified with genes for cytoplasmic male sterility (cms female line - mother line) and restoration of fertility (Rf male lines - father line). In order to maintain the sterility of the mother line it is necessary to produce a maintainer line of cytoplasmic male sterility. Creation of these lines and hybrids at the Institute of Field and Vegetable Crops was successfully monitored with intense use of cytogenetic laboratory methods. The structure and vitality of pollen, including different phases during meiosis were checked so that cms stability was confirmed during the introduction of these genes into different lines. Rapeseed breeding program in Serbia resulted in numerous varieties through collaboration of researchers engaged in breeding and genetics of this plant species. So far, in addition to 12 varieties of winter rapeseed and two varieties of spring rapeseed, a new hybrid of winter rapeseed NS Ras was registered in Serbia. NS Ras is an early-maturing hybrid characterized by high seed yield and oil content. Average yield of NS Ras for two seasons and three sites was 4256 kg ha-1 of seed and 1704 kg ha-1 of oil. Three promising winter rapeseed hybrids are in the process of registration in the Republic of Serbia and one in the EU. While addressing many challenges in breeding, especially resistance to biotic and abiotic stress, in addition to classical breeding, it is necessary to apply the cytogenetic and molecular analysis to increase the efficiency of producing competitive rapeseed genotypes.Porast proizvodnje uljane repice (Brassica napus L.) evidentan je u svetskim razmerama, a poslednje decenije i u Srbiji. Uljana repica se koristi prvenstveno za dobijanje ulja za ishranu i prerađivačku industriju, ali i kao izvor proteina za ishranu domaćih životinja i zelenišno đubrivo. Nakon gajenja sorti počelo se 90-ih godina prošlog veka sa oplemenjivanjem i gajenjem hibrida uljane repice, kako bi se iskoristio efekat heterozisa u F1 generaciji, uz istovremenu zaštitu prava oplemenjivača prilikom prometa semena. U oplemenjivanju hibrida uljane repice neophodno je u kvalitetan početni materijal (linije dobrih kombinacionih sposobnosti) uneti svojstvo muške sterilnosti. U Institutu za ratarstvo i povrtarstvo, Novi Sad koristi se prvenstveno Ogura sistem sterilnosti. Korišćenje ovog sistema obuhvata unošenje citoplazmatske muške sterilnosti (cms linije majke) i gena za restauraciju fertilnosti (Rf linije oca). Da bi se sterilnost linije majke održala neophodno je proizvesti i liniju održivača citoplazmatske muške sterilnosti. Prilikom stvaranja ovih linija, hibrida i u semenskoj proizvodnji u Institutu za ratarstvo i povrtarstvo intenzivno i vrlo uspešno su korišćene citogenetske laboratorijske metode. Analizirana je građa i vitalnost polena, kao i različite faze tokom mejoze i utvrđena stabilnost svojstava prilikom unošenja ovih gena u različite linije. U oplemenjivanju uljane repice u Srbiji postignuti su značajni rezultati kroz saradnju istraživača koji se bave genetikom i oplemenjivanjem ove biljne vrste. Do sada je pored 12 sorti ozime i dve sorte jare repice u Srbiji registrovan hibrid ozime uljane repice NS Ras. NS Ras je ranostasni hibrid koji se odlikuje visokim prinosom zrna i ulja. Prosečan prinos u dve sezone za tri lokaliteta je bio 4256 kg ha-1 semena i 1704 kg ha-1 ulja. Još tri perspektivna ozima hibrida uljane repice nalaze se u postupku registracije u republici Srbiji i jedan u EU. U rešavanju mnogih izazova u oplemenjivanju, prvenstveno otpornosti na biotski i abiotski stres, pored klasičnog oplemenjivanja neophodno je primeniti, citogenetske i molekularne analize za povećanje efikasnosti oplemenjivanja uljane repice

NS Zlatka and NS Slatka – the first Serbian cultivars of camelina (Camelina sativa L. Crantz)

NS Zlatka i NS Slatka su registrovane u Srbiji kao prve sorte lanika (Camelina sativa, L. Crantz) 2018.godine, ali je seme ove vrste naĊeno u arheološkim nalazištima još iz bronzanog doba na podruĉju severnog Balkana. Poslednjih godina interes za lanikom se ponovo povećava zbog njegove raznovrsne upotrebe i skromnih agroekoloških zahteva gajenja. U dvogodišnjem ogledu sorte kanditati su ispitivane u tri lokaliteta: Sombor, Panĉevo i Novi Sad prema Pravilniku o metodama ispitivanja sorte lanika radi priznavanja sorte. Proizvodna i upotrebna vrednost sorte utvrĊena se na osnovu rezultata ispitivanja bitnih osobina sorte za ovu vrstu. Proseĉan prinos semena nešto je veći kod sorte NS Zlatka (1056 kg/ha) nego kod sorte NS Slatka (1019 kg/ha). Sadrţaj ulja kod obe sorte je gotovo jednak 42,28% (NS Zlatka) i 42,12% (NS Slatka), pri ĉemu prinos semena uzrokuje veći prinosu ulja od 6 kg/ha kod sorte NS Zlatka.NS Zlatka and NS Slatka cultivars were registered in Serbia in 2018. They were the first cultivars of Camelina (Camelina sativa, L. Crantz) even though Camelina seeds were found at the Bronze Age archeological sites in the northern Balkan Peninsula. The recent increased interest in Camelina is due to its versatility and environmental flexibility. Candidate cultivars were tested in a two-year trial at three localities - Sombor, Panĉevo, and Novi Sad - according to the regulations on the methods of testing Camelina for cultivar registration purposes. The usability and value of the cultivars was determined according to the analysis of significant cultivar traits. Average seed yield of NS Zlatka cultivar was slightly higher (1056 kg/ha) compared to NS Slatka (1019 kg/ha). Oil content of the cultivars was almost the same: 42.28% (NS Zlatka) and 42.12% (NS Slatka), whereas higher seed yield resulted in higher oil yield, amounting to 6 kg/ha obtained from the cultivar NS Zlatka

Stability of Discrete-Time Fractional Order Systems considered: An Approach Based on Stability of Discrete-Time Integer Order Time-Delay Systems

In this paper the problem of stability of linear discrete-time fractional order systems is addressed. It was shown that some stability criteria for discrete time-delay systems could be applied with small changes to discrete fractional order state-space systems. Accordingly, simple conditions for the stability and robust stability of a particular class of linear discrete time-delay systems are derived. These results are modified and used for checking the stability of discrete-time fractional order systems. The systems under consideration involve time delays in the state and parameter uncertainties. The parameter uncertainties are assumed to be time-varying and norm bounded. New Lyapunov–Krasovskii functional is constructed to derive some delay dependent stability criteria. The proposed methods give both sufficient and necessary and sufficient stability conditions. Numerical examples have been worked out to show the applicability of the derived results

Simple exponential stability criteria of linear discrete time-delay systems

In this paper, new delay-independent asymptotic and exponential stability conditions of linear discrete delay systems based on the Lyapunov-Krasovskii method have been derived. A numerical example has been developed so as to show applicability of the derived results