Analysis of input-to-state stability for discrete time nonlinear systems via dynamic programming

The input-to-state stability (ISS) property for systems with disturbances has received considerable attention over the past decade or so, with many applications and characterizations reported in the literature. The main purpose of this paper is to present analysis results for ISS that utilize dynamic programming techniques to characterize minimal ISS gains and transient bounds. These characterizations naturally lead to computable necessary and sufficient conditions for ISS. Our results make a connection between ISS and optimization problems in nonlinear dissipative systems theory (including L2-gain analysis and nonlinear H∞ theory). As such, the results presented address an obvious gap in the literature. © 2005 Elsevier Ltd. All rights reserved

A unified approach to controller design for achieving ISS and related properties

A unified approach to the design of controllers achieving various specified input-to-state stability (ISS) like properties is presented. Both full state and measurement feedback cases are considered. Synthesis procedures based on dynamic programming are given using the recently developed results on controller synthesis to achieve uniform l∞ bound. Our results provide a link between the ISS literature and the nonlinear H∞ design literature. © 2005 IEEE

Measurement feedback controller design to achieve input to state stability

An approach for design of measurement feedback controllers achieving input-to-state (ISS) stability properties is presented. A synthesis procedure based on dynamic programming is given. We make use of recently developed results on controller synthesis to achieve uniform l∞ bound [6]. Our results make an important connection between the ISS literature and nonlinear H∞ design methods

Identification of A Neural Mass Model of Burst Suppression

Burst suppression includes alternating patterns of silent and fast spike activities in neuronal activities observable (in micro or macro scale) electro-physiological recordings. Biological models of burst suppression are given as dynamical systems with slow and fast states. The aim of this paper is to give a method to identify parameters of a mesoscopic model of burst suppression that can provide insights into study underlying generators of intracranial electroencephalogram (iEEG) data. An optimisation technique based upon a genetic algorithm (GA) is employed to find feasible model parameters to replicate burst patterns in the iEEG data with paroxysmal transitions. Then, a continuous-discrete unscented Kalman filter (CD-UKF) is used to infer hidden states of the model and to enhance the identification results from the GA. The results show promise in finding the model parameters of a partially observed mesoscopic model of burst suppression

Topography, morphology, vascularization and inervation of the abdominal organs in the mole rat (Spalax leucodon)

U relevantnoj literaturi ima malo podataka o topografiji, morfologiji, mikroskopskoj građi, vaskularizaciji i inervaciji organa trbušne duplje slepog kučeta (Spalax leucodon), pa smo zato odlučili da ispitamo trbušnu duplju, topografiju, morfologiju, vaskularizaciju i inervaciju trbušnog dela jednjaka (Pars abdominalis), želuca (Ventriculus), tankog creva (dvanaestopalačnog creva-Duodenum, praznog creva-Jejunum i vitog creva-Ileum), debelog creva (slepog creva-Cecum, kolona-Colon i pravog creva-Rectum), jetre (Hepar) i žučne kanale, slezine (Lien), gušterače (Pancreas) i bubrega (Ren). Ispitivali smo i topografiju i granjanje trbušne aorte (Aorta abdominalis), topografiju i pritoke kaudalne šuplje vene (V. cava caudalis) i vene ekstrahepatičnog dela portalnog krvotoka jetre. Rezultate našeg ispitivanja upotpunili smo opisom histološke građe trbušnog dela jednjaka, želuca, tankog creva, debelog creva, jetre, slezine, gušterače, bubrega, trbušne aorte i kaudalne šuplje vene. Kvantitativna analiza zida trbušne aorte i kolona vršena je linearnim i stereološkim merenjima pomoću mnogonamenskog test sistema M42. Kao material za izučavanje koristili smo organe trbušne duplje slepog kučeta (Spalax leucodon) sveže i konzervisane preparate iz kolekcije Katedre za anatomiju Fakulteta veterinarske medicine u Beogradu. Slepi kučići hvatani su na terenu Južnog Banata i to u mestu Šušara kod Uljme (Deliblatska peščara). Obzirom da je u Republici Srbiji slepo kuče zaštićeno zakonom kao prirodna retkost, dobili smo odobrenje Etičkog komiteta Fakulteta veterinarske medicine u Beogradu, dekana Fakulteta veterinarske medicine u Beogradu i Ministarstva zaštite životne sredine Republike Srbije za nabavku deset slepih kučića iz prirode. Za ispitivanje koristili smo anatomske, histološke, morfometrijske i stereološke metode rada. Uz obaveznu anesteziju primenom preparata ketamina (Ketamidor 10%) uz premedikaciju Ksilazinom, životinje su bile žrtvovane. Za morfološko ispitivanje preparati su posmatrani golim okom ili pod stonom lupom, uvećanje 1,75x...Data on morphology, topography, vascularization and innervation of the abdominal cavity organs of the mole rat (Spalax leucodon) published in the reference literature are scarce, and therefore we have decided to study abdominal cavity, topography, morphology, vascularization and innervation of the abdominal portion of the esophagus, stomach, small intestine (duodenum, jejunum and ileum), large intestine (cecum, colon and rectum), liver and its bile ducts, spleen, pancreas and kidneys. Topography and branches of the abdominal aorta, topography and tributaries of the caudal vena cava as well as extrahepatic veins of the portal system were studied as well. The results of our study were supplemented by description of the histological structure of the abdominal portion of the esophagus, stomach, small intestine, large intestine, liver, spleen, pancreas, kidneys, abdominal aorta and caudal vena cava. Quantitative analysis of the wall of the abdominal aorta and all parts of the colon was perfomed linear measurements and stereological measurement using test system M42. Abdominal cavity organs of the mole rat were used as material for investigation both as fresh and preserved preparations from the collection of the Department of Anatomy of the Faculty of Veterinary Medicine in Belgrade. Mole rats were traped on the area of south Banat in the village of Šušara near Uljma (Deliblatska peščara). Since mole rat is protected by law in Republic of Serbia as natural rarities, the approvals of the Ethics Committee and Dean,s of the Faculty of Veterinary Medicine in Belgrade as and Ministry of Environmental Protection of the Republic of Serbia were obtained for provision of 10 mole rats from their natural habitats..

Ispitivanje mogućnosti korišćenja nanočestica TiO2 kao nosača za ciljanu i kontrolisanu dostavu lekova na bazi kompleksa prelaznih metala

Sinteza i primena kompleksa prelaznih metala u lečenju kancera je predmet istraživanja velikog broja naučnika. Potreba za razvojem novih citostatika proizilazi iz želje da se prevaziđu nedostaci već postojećih, kao što su rezistencija, toksičnost i uzak terapeutski opseg (aktivnost protiv malog broja tipova tumora). Tako se pored kompleksa platine, i dalje najčešće korišćenih citostatika u kliničkoj praksi, razvila čitava serija novih kompleksa redizajniranjem već postojećih izmenom liganada i/ili izmenom centralnog metalnog jona. Posebno su se izdvojili kompleksi rutenijuma zbog manje toksičnosti, aktivnosti na metastazama i tumorima na kojima su dotadašnji citostatici bili neaktivni, a neki od njih su pokazali aktivnost tek kada se ozrače svetlošću odgovarajuće talasne dužine i potencijal za primenu u fotodinamičkoj terapiji. Uprkos razvoju novih generacija citostatika s poboljšanim karakteristikama, kao problem ostaje kontrola postizanja maksimalne koncentracije leka u tumorskom tkivu. Na putu do ciljnog, tumorskog tkiva i ciljnih biomolekula, lek interaguje i s brojnim drugim biomolekulima što za posledicu može imati toksičnost, pojavu rezistencije, inaktivaciju leka i smanjenje njegove efektivne koncentracije na željenom mestu dejstva. Potreba za prevazilaženjem ovog problema dovela je do brzog razvoja nosača za lekove. Njihova uloga je da vežu ili inkapsuliraju lek, nose ga do tumorskog tkiva sprečavajući njegovu interakciju s okolnim biomolekulima i zatim ga otpuste, aktivnim ili pasivnim mehanizmom, u ciljnom tumorskom tkivu. Cilj upotrebe ovakvih sistema je smanjenje štetnog dejstva leka na zdravo tkivo, mogućnost kontrole doziranja leka tj. postizanje njegove optimalne koncentracije u tumorskom tkivu, a samim tim i postizanje veće efikasnosti terapije. Nosači koji se testiraju za mogućnost primene u kontrolisanoj i ciljanoj dostavi medikamenata su uglavnom na bazi organskih i neorganskih nanomaterijala, međutim mali broj njih je u kliničkoj upotrebi (lipozomi i polimerni nanomaterijali). U fazi ispitivanja su mnogobrojni nosači koji reaguju na stimulanse kao što su pH sredine, ultrazvuk, temperatura i svetlost. U novijim istraživanjima veliku pažnju kao nosači za lekove zauzimaju nanočestice TiO2 zbog svoje biokompatibilnosti, fotoaktivnosti, dostupnosti i mogućnosti modifikacije površine.A significantly rising interest in the design and use of metal complexes for cancer treatment is currently observed in the area of scientific inquiry. There has been a growing demand for development and improvement of metal-based compounds used in routine clinical practice in order to overcome disadvantages and limitations such as resistance, toxicity and narrow spectrum of activity (activity against a small number of tumor types). Beside platinum complexes, the leading agents in clinical use, many more metal-based compounds have been synthesized by redesigning the existing chemical structure through ligand substitution and/or central metal ion switching. Among them ruthenium complexes have been investigated as one of the most promising candidates because they shown less toxicity, significant activity against cancer metastases, and activity on tumors that were resistant to a variety of standard chemotherapeutic agents. Moreover, some of them are light sensitive drugs i.e. their functions is triggered once they are activated by light of a specific wavelength which make them promising candidates for photodynamic therapy. Despite fast development of new generation of cytostatics with better characteristics, there are still areas where substantial improvements need to be made. One such area is achievement of a maximum concentration of the drug on tumor site. Once the drug enters the systemic circulation, it could face a number of challenges. Drug could react with nontarget biomolecules on its way to target biomolecules in tumor tissue which could cause severe side effects such as toxicity, resistance, inactivation of the drug and reduction of its effective concentration at the target tumor site. One way to solve these problems is the development of drug delivery systems which consist of drug and drug carrier. Role of drug carriers is to bind or encapsulate the drug, prevent its interaction with non-target biomolecules, to carry the drug to the target tumor tissue and then release it with active or passive mechanism. The main advantages of using drug delivery systems are reduction of side effects of drug onto the healthy tissue, dosage control, optimal concentration of drug in the tumor tissue, and more effective treatment which could improve outcome of therapy. Many organic and inorganic nanoparticles have been tested as drug carriers, but just few of them are in clinical use (liposomes and polymers). In recent years smart nanosystems for targeted drug delivery that respond to various stimuli including pH, ultrasound, temperature and light irradiation are in the center of many investigations

On the torque transmission by a Cardan-Hooke joint

Proučavana je kinemtika i dinamika Kardan-Hukovog zgloba. Kinematička analiza se bazira na teoriji složenog kretanja krutog tela. Dinamička analiza Kardan-Hukovog zgloba je izvršena na bazi Lagranževih jednačina druge vrste. Kardan-Hukov zglob je analiziran u uslovima promenljive ugaone brzine pogonskog (ulaznog) vratila zgloba. Razmatrane su dve varijante zgloba: (1) ravan pogonske viljuške se poklapa sa ravni vratila; (2) ravan pogonske viljuške je normalna na ravan vratila. Izveden je izraz kojim se opisuje prenos obrtnog momenta Kardan-Hukovim zglobom. Izvedeni izraz sadrži članove koji potiču od inercije ulaznog i izlaznog vratila kao i od inercije krsta Kardan-Hukovog zgloba. Teorijska razmatranja su propraćena numeričkim primerom.Kinematics and dynamics of a Cardan-Hooke joint are investigated. Kinematic analysis is based on the kinematic chain rule for angular velocity vectors. Dynamics of the Cardan-Hooke joint is analyzed by means of the Lagrange equations of the second kind. The Cardan-Hooke joint is analysed under varying operating conditions, that is, it is assumed that the input shaft has variable angular velocity. Two cases are considered: (1) the driving yoke plane coincides with the plane of the shafts; (2) the driving yoke plane is normal to the plane of the shafts. An expression for torque transmission in a Cardan-Hooke joint in varying operating conditions was developed. The expression contains terms representing inertia of the shafts and the cross of the Cardan-Hooke joint. Theoretical considerations are accompanied by a numerical example

Decentralized event-triggered estimation of nonlinear systems

We investigate the scenario where a perturbed nonlinear system transmits its output measurements to a remote observer via a packet-based communication network. The sensors are grouped into N nodes and each of these nodes decides when its measured data is transmitted over the network independently. The objective is to design both the observer and the local transmission policies in order to obtain accurate state estimates, while only sporadically using the communication network. In particular, given a general nonlinear observer designed in continuous-time satisfying an input-to-state stability property, we explain how to systematically design a dynamic event-triggering rule for each sensor node that avoids the use of a copy of the observer, thereby keeping local calculation simple. We prove the practical convergence property of the estimation error to the origin and we show that there exists a uniform strictly positive minimum inter-event time for each local triggering rule under mild conditions on the plant. The efficiency of the proposed techniques is illustrated on a numerical case study of a flexible robotic arm

Effect of acute exercise on serum growth hormone and fatty acid levels in elite male water polo players

The aim of study was to estimate the effect of acute exercise on serum growth hormone (GH) and fatty acid (FFA) levels in elite water polo players. Twelve male water polo players (20.50 ± 2.02 years) and eleven non-athletic male subjects (20.55 ± 1.04 years) participated in this study. In order to determine GH and FFA responses to acute exercise, a treadmill-running test was performed following an incremental protocol. Pre-exercise blood samples for both athletes and non-athletes were taken at 9 AM. Post-exercise samples were taken immediately after and 30 min after the treadmill running test. Water polo players had significantly lower baseline values of serum GH concentration compared to controls, whereas serum FFA concentration was significantly higher in water polo players compared to controls (p<0.01; p<0.05, respectively). In both groups, concentration of GH was significantly higher immediately after and after the 30-min of recovery compared to baseline levels (p<0.05). In water polo players, the concentration of FFA was significantly decreased immediately after and after the 30-min of recovery compared to baseline levels (p<0.05). No significant response to maximal exercise test was observed in the control group for serum FFA concentration. Our research indicates that acute exercise resulted in a significant increase in serum GH and reduction in fatty acid levels in elite water polo players. [Projekat Ministarstva nauke Republike Srbije, br. OI 175067

Arterijska vaskularizacija amigdale psa

We investigated the vascularization of the amygdala of the dog using various contrast agents injected into the internal carotid and vertebral artery. Subsequent clearance of the tissues gives us an opportunity to study the finest capillary network in the amygdala. The corticomedial part of the amygdala has a good vascularization given by the rostral and caudal choroid arteries. The rostral choroid gives off a rich capillary net to the nucleus centralis (NCE), its pars lateralis (NCEL) and pars medialis (NCEM). Nucleus medialis (NM) is poorly vascularized compared to the central nuclei. The massa intercalata (MI) also has a delicate artery around which there is a fine net of capillaries. Nucleus corticalis (NCO) and area enthorhinalis (AER) are better vascularized by the subpial blood vessel. The caudal choroid, a branch of the caudal cerebral artery is a source of subpial capillaries. The basolateral part of the amygdala is very well vascularized by the rostral choroid artery, a branch of the middle cerebral, especially the nucleus basolateralis (NBL) and nucleus lateralis posterior (NLP). The nucleus basomedialis (NBM) is poorly vascularize by the rostral choroid artery . The amygdala, is served by the middle cerebral artery, via its branch, the rostral choroid, and the caudal cerebral artery via its branch the caudal choroid artery. Every amygdala nucleus has its own central artery around which is formed a rich net of capillaries.Proučavanje vaskularizacije amigdale psa vršeno je upotrebom različitih kontrasnih sredstava injiciranih u a. carotis interna i a. vertebralis a prosvetljavanje tkiva daje mogućnost da se prouči i najfinija vaskularna mreža u amigdali. Kortikomedijalni deo amigdale vaskularišu a. choroidea rostralis i a. choroidea caudalis. A. choroidea rostralis, daje bogatu mrežu kapilara u NCE (nucleus centralis) i njegovom lateralnom i medijalnom delu (NCEL i NCEM). Nucleus medialis (NME) je slabije vaskularisan u poredjenju sa vaskularizacijom NCE. Massa intercalata (MI) je takodje snabdevena bogatom mrežom kapilara. A. choroidea caudalis, kao subpialna arterija, vaskulariše NCO (nucleus corticalis) i AER (area enthorhinalis). Bazolateralni deo amigdale vaskulariše samo a. choroid rostralis. Bogata mreža kapilara uočava se u NBL (nucleus basolateralis) i NLP (nucleus lateralis posterior) a nešto siromašnija u NBM (nucleus basomedialis). Krv u amigdalu dovode dve arterije: a. choroidea rostralis, grana od a. cerebri media, i a. choroidea caudalis, grana od a. cerebri caudalis. Svaki nukleus amigdale ima svoju centralnu arteriju i oko nje jako razvijenu mrežu kapilara