ON FUNDAMENTAL OPERATING PRINCIPLES AND RANGE-DOPPLER ESTIMATION IN MONOLITHIC FREQUENCY-MODULATED CONTINUOUS-WAVE RADAR SENSORS

The diverse application areas of emerging monolithic noncontactradar sensors that are able to measure object’s distance and velocity is expected to grow in the near future to scales that are now nearly inconceivable. A classical concept of frequency-modulated continuous-wave (FMCW) radar, tailored to operate in the millimeter-wave (mm-wave) band, is well-suited to be implemented in the baseline CMOS or BiCMOS process technologies. High volume production could radically cut the cost and decrease the form factorof such sensing devices thus enabling their omnipresence in virtually every field. This introductory paper explains the key concepts of mm-wave sensing starting from a chirp as an essential signal in linear FMCW radars. It further sketches the fundamental operating principles and block structure of contemporary fully integrated homodyne FMCW radars. Crucial radar parameters like the maximum unambiguously measurable distance and speed, as well as rangeand velocity resolutions are specified and derived. The importance of both beat tones in the intermediate frequency (IF) signal and the phase in resolving small spatial perturbations and obtaining the 2-D range-Doppler plot is pointed out. Radar system-level trade-offs and chirp/frame design strategies are explained. Finally, the nonideal and second-order effects are commented and the examples of practical FMCW transmitter and receiver implementations are summarized

Razvoj metodologije za eksperimentalnu i numeričku procenu integriteta nosećih delova vagonske konstrukcije izloženih cikličnom dinamičkom opterećenju

Iz inženjerske prakse je poznato da su vagonske čelične konstrukcije tokom eksploatacije izložene složenim kombinovanim opterećenjima. Modernizacijom pruga, povećavanjem brzine kretanja, optimizacijom vagonskih konstrukcija, korišćenjem novih materijala, stvoreni su veliki izazovi u oblasti vagonske industrije. Paralelno sa povećanjem izazova, zahtevi u pogledu pouzdanosti i bezbednosti vagonskih konstrukcija postajali su sve veći. Predmet proučavanja i cilj rada na ovoj disertaciji je razvoj pouzdane metodologije za eksperimentalnu i numeričku procenu integriteta vagonskih konstrukcija izloženih promenljivim dinamičkim opterećenjima. Za potrebe procene integriteta delova vagonskih konstrukcija eksperimentalno su određivane karakteristike konstrukcionih čelika i čelika koji su već bili u fazi eksploatacije. Cilj ovih eksperimentalnih istraživanja je dobijanje dovoljnog broja podataka o materijalima i geometriji kritičnih zona vagonskih konstrukcija. Sistematizacijom dobijenih rezultata i onih koji su već dostupni u raznim oblicima literature napravljena je osnova za tumačenje rezultata dobijenih numeričkim proračunima. Kao plod razvijene metodologije, na realnim primerima iz prakse, prikazan je postupak procene integriteta nosećih delova rekonstruisane vagonske konstrukcije, koja je izložena promenljivim zamornim opterećenjima. Na osnovu eksperimentalnih i numeričkih rezultata izvršena je analiza postavljenog problema u skladu sa standardima u oblasti vagonskih konstrukcija. Drugi primer predstavlja procenu preostalog radnog veka, određivanje broja ciklusa do otkaza kritičnih zona nosećih delova vagonske konstrukcije na osnovu eksperimentalno dobijenih podataka i numeričkih rezultata proračuna. Korišćenje razvijene metodologije na konkretnim primerima i njena verifikacija u praksi, dovodi do znatne uštede pri veoma skupim ispitivanjima različitih prototipova vagona. Praktična primena razvijene metodologije u budućnosti bi mogla ostvariti pozitivan uticaj u oblasti vagonske industrije.It is well known from the engineering experience that, during exploitation, steel structures of wagons are exposed to the complex combined loads. Modernization of rails by increasing the velocity, optimization of the wagon structures, using new materials, created great challenges in the field of wagon industry. Together with increasing challenges, the requirements in terms of reliability and safety of the wagon structure have increased as well. The subject of studying and purpose of this thesis is to develop a reliable methodology for the experimental and numerical evaluation of the integrity of the wagon structures exposed to the alternating dynamic loads. For the purpose of integrity estimation of the wagon parts, the characteristics of structural steel and steel in the phase of exploitation have been experimentally determined. The aim of this experimental research is to obtain sufficient data on materials and geometry relating to the critical zones of the wagon structures. Systematization of the obtained results and those that are already available in various forms of literature enabled forming the basis for the interpretation of the results of the numerical calculations. As a result of the developed methodology, the procedure of assessment of the integrity of loadbearing parts of the reconstructed wagon structure exposed to fatigue loads, is presented on the real examples in practice. The analysis of a problem was performed in accordance with the standards in the field of the wagon industry and based on the experimental and numerical results. Another example presents the remaining service life assessment, determination of the number of cycles to failure of critical load-bearing parts of the wagon structure according to the experimental data and numerical calculation results. Using of the developed methodology on concrete examples and its verification in practice lead to the significant savings in the very expensive tests of different prototypes of the wagon. Practical application of the developed methodology in the future could have a positive impact in the field of the wagon industry

Evaluation of the importance of modified ultrafiltration in pediatric cardiac surgery.

Kardiopulmonalni bajpas (KPB), pogotovo u pedijatrijskoj kardiohirurgiji, je značajan uzrok postoperativnog morbiditeta. Pedijatrijski pacijenti, zbog primene KPB-a, razvijaju snažnu sistemsku inflamatornu reakciju koja rezultira povećanom propustljivošću kapilara i multiorganskom disfunkcijom. Ultrafiltracija, tokom i posle KPB-a, je značajna tehnika u borbi protiv neželjenih efekata KPB-a. Modifikovana ultrafiltracija (MUF) je u prethodnim godinama postala široko prihvaćena tehnika ultrafiltracije u pedijatrijskoj kardiohirurgiji. Ova studija ima za cilj da ispita da li primena MUF, kao dela kombinovane strategije ultrafiltracije (sa konvencionalnom ultrafiltracijom), ima uticaj na parametre kliničkog stanja ranog postoperativnog toka dece operisane zbog urođenih srčanih mana, a u uslovima smanjene upotrebe hipotermije i smanjenja stepena hemodilucije. Materijal i metode: Studija je obuhvatila 98 uzastopnih pedijatrijskih pacijenata (velika kohorta) telesne mase do 12 kg, sa urođenim srčanim manama koji su podvrgnuti kardiohirurškoj korekciji upotrebom KPB-a. Pacijenti su podeljeni u u dve grupe na osnovu sprovedene procedure (MUF i Non MUF), a posebna pažnja je posvećena pacijentima telesne mase do 5 kg ( mala kohorta, 49 pacijenata). Standardizovani institucionalni anesteziološki i perfuzioni protokoli su primenjeni kod sve operisane dece. Izostanak MUF u non MUF grupi je bila jedina razlika u perfuzionoj praksi operisanih pacijenata. Rezultati: Post filtracioni hematokrit je bio statistički značajno veći u MUF grupi obe kohorte (velika kohorta p= 0.001; mala kohorta p=0.04). U postoperativnom toka pacijenti MUF grupe ređe su zahtevali transfuziju deplazmatisanih eritrocita (velika kohorta p=0.01; mala kohorta cohort p=0.07), ali su češće primali sveže smrznutu plazmu (velika kohorta p=0.04; mala kohorta p=0.05). Među grupama obe kohorte nije bilo razlike u hemodinamskom statusu, postoperativnoj drenaži, brojnim respiratornim parametrima i dužini mehaničke ventilacije, dužini boravka u odeljenju intenzivne nege i dužini hospitalizacije. Zaključak: Ukoliko konvencionalana ultrafiltracija obezbedi adekvatnu hemokoncentraciju, MUF ne rezultira pozitivnim efektima, osim smanjene potrebe za postoperativnom transfuzijom krvi. Sa druge strane, MUF uzrokuje veću primenu sveže smrznute plazme u postoperativnom periodu. Od naročitog interesa je da ovo važi i za pacijente telesne mase do 5 kg, kod kojih bi MUF trebalo da ima najizraženije pozitivne efekte.Cardiopulmonary bypasses (CPB), particularly in pediatric cardiac surgery, significantly contributes to the development of postoperative morbidity. Pediatric patients due to CPB develop a systemic inflammatory response syndrome which increases total body water and may result in multi-organ dysfunction. Ultrafiltration, during and after CPB, is an important tool which mitigates these side effects. Modified ultrafiltration (MUF) has gained wide acceptance as a powerful tool against cardiopulmonary bypass morbidity in the previous years. The present study aimed to reevaluate the importance of MUF as a part of combined ultrafiltration strategy on early clinical outcomes in infants undergoing pediatric cardiac surgery within conditions of decreased use of hypothermia and mitigation of hemodilution. Methods: Ninety-eight patients (overall cohort) weighing less than 12 kg who underwent surgical repair with cardiopulmonary bypass for functionally biventricular congenital heart disease were randomized to receive modified and conventional ultrafiltration (MUF group) or just conventional ultrafiltration (No MUF group). A special attention was paid to forty-nine neonates and infants weighing less than 5 kg (small cohort). where the benefits of ultrafiltration are expected to be more pronounced. Patient management was standardized, the outcome assessors were blinded to group allocation. Results: Post filtration hematocrit was significantly higher in the MUF group for both cohorts (overall cohort p= 0.001; LW cohort p=0.04), but not at other time points. During the postoperative course, patients in the MUF group received fewer packed red blood cells, (overall cohort p=0.01; LW cohort p=0.07), but required more fresh frozen plasma (overall cohort p=0.04; LW cohort p=0.05). There was no difference between groups in hemodynamic state, chest tube output, duration of mechanical ventilation, respiratory parameters, duration of intensive care unit and hospitalization stay. Conclusions: If conventional ultrafiltration provides adequate hemoconcentration modified ultrafiltration does not provide additional positive benefits except for reduction in blood cell transfusion, This, however, comes at the cost of needing more fresh frozen plasma. Of particular importance is that this also applies to infants with weight bellow 5 kg where modified ultrafiltration was supposed to have the greatest positive impact

Uloga klirinških kuća u razvoju trgovanja izvedenim hartijama od vrednosti u Srbiji

The aim of the study was to analyze and suggest the optimal clearinghouse models in order to develop derivative contracts in the Serbia. One of the main characteristics of modern business is dynamics and increased degree of uncertainty. As a result of increased uncertainty, need for the development of trade with derivative securities on organized markets, as a risk management instruments, is increased. A necessary prerequisite for trading with these securities is a clearinghouse. The study shows that the developed derivative exchanges have beneficial and pronounced impact on the segment of risk management in the financial sector as well as in the commodity sector. The optimal model of clearing in Serbia is establishment of two clearinghouse models in the house clearinghouses and independent clearinghouses.Cilj rada je utvrđivanje optimalnog modela kliringa za razvoj tržišta derivatnih ugovora u Srbiji. Jedna od osnovnih karakteristika savremenog poslovanja je dinamičnost i povećanje stepena neizvesnosti. Kao posledica ovakvih pojava javila se potreba za razvojem trgovanja izvedenim hartijama od vrednosti na organizovanim tržištima, čime bi se poslovanje učinilo izvesnijim. Neophodan preduslov za trgovanje ovom vrstom hartija od vrednosti je uspostavljanje klirinške kuće. Rezultati rada pokazuju da bi tržište derivatnih ugovora imalo značajan povoljan uticaj na segment upravljanja rizikom u finansijskom sektoru kao i u robnom sektoru. Optimalan model kliringa u Srbiji bi bio omogućavanje osnivanja klirinške kuće na samoj berzi kao i nezavisne klirinške kuće

Application of the 3r concept in the production of European antiviperinum on horses - multisite, low volumes immunization protocol and Elisa

During time, both professionals and general public became aware of the importance of animal welfare. This term not only covers endangered wild animal species, animals used in food industry, pets and experimental animals, but also animals used in production of biologics. The implementation of the 3R concept (Replacement, Reduction and Refinement) is especially important in this type of production. In this article, we describe for the first time the low dose, low volume and multi-site immunization protocol, as well as appropriate ELISA we developed for production of European anti-viper (V. ammodytes, long horned) antivenom in horses, which can help to significantly improve the welfare of the used animals

A DOUBLE-DIFFERENTIAL-INPUT /DIFFERENTIAL-OUTPUT FULLY COMPLEMENTARY AND SELF-BIASED ASYNCHRONOUS CMOS COMPARATOR

A novel fully complementary and fully differential asynchronous CMOS comparator architecture, that consists of a two-stage preamplifier cas- caded with a latch, achieves a sub-100 ps propagation delay for a 50mVpp and higher input signal amplitudes under 1.1V supply and 2.1mWpower consumption. The proposed voltage comparator topology features two differential pairs of inputs (four in total) thus increasing signal-to-noise ratio (SNR) and noise immunity through rejection of the coupled noise components, reduced even-order harmonic distortion, and doubled output voltage swing. In addition to that, the comparator is truly self-biased via negative feedback loop thereby eliminating the need for a voltage reference and suppressing the influence of process, supply voltage and ambient temperature variations. The described analog comparator prototype occupies 0.001mm2 in a purely digital 40 nm LP (low-power) CMOS process technology. All the above mentioned merits make it highly attractive for use as a building block in implementation of the leading-edge system-on-chip (SoC) data transceivers and data converters

Experimental and FE Modeling Investigation of Spot Welded Thin Steel Sheets

The spot welded thin steel sheets specimens are experimentally and numerically examined in this paper. The two specimens are joined using Resistance Spot Welding (RSW) method. The spot-welded joints consist of three zones with different material properties. Change of material properties during the welding process is caused by mechanical and thermal loading. The mechanical properties of thin steel sheets are determined by several tension tests. The specimens are cut in three different directions regarding a rolling direction of the basic material plate. Shear resistance of the spot welded joints is experimentally examined on the universal testing machine by displacement-controlled tensile loading tests. The numerical analysis is performed by large-strain plasticity theory implemented into a Finite Element Method based software. Comparison of the Finite Element (FE) modeling and experimental results verifies the proposed stress integration algorithm and modeling technique as powerful tools for prediction of the spot-welded joint behavior

Elektronski registar robnih zapisa kao korak od papirnog ka elektronskom robnom zapisu

The aim of this paper is to determine the economic viability of the electronic warehouse receipt registry introduction, as a step toward electronic warehouse receipts. Both forms of warehouse receipt paper and electronic exist in practice, but paper warehouse receipts are more widespread. In this paper, the dematerialization process is analyzed in two steps. The first step is the dematerialization of warehouse receipt registry, with warehouse receipts still in paper form. The second step is the introduction of electronic warehouse receipts themselves. Dematerialization of warehouse receipts is more complex than that for financial securities, because of the individual characteristics of each warehouse receipt. As a consequence, electronic warehouse receipts are in place for only to a handful of commodities, namely cotton and a few grains. Nevertheless, the movement towards the electronic warehouse receipt, which began several decades ago with financial securities, is now taking hold in the agricultural sector. In this paper is analyzed Serbian electronic registry, since the Serbia is first country in EU with electronic warehouse receipts registry donated by FAO. Performed analysis shows the considerable impact of electronic warehouse receipts registry establishment on enhancing the security of the system of public warehouses, and on advancing the trade with warehouse receipt.Cilj ovog rada je da se utvrdi ekonomska opravdanost uvođenja elektronske evidencije robnog zapisa, kao koraka ka uvođenju u potpunosti elektronskog robnog zapisa. Obe forme robnog zapisa postoje u praksi, ali je papirni oblik robnog zapisa više u upotrebi. U ovom radu proces dematerijalizacije je analiziran u dva koraka. Prvi je dematerijalizacija knjige robnih zapisa, dok je robni zapis u papirnoj formi. Drugi korak je uvođenje potpunog sistema elektronskog robnog zapisa. Dematerijalizacija robnog zapisa je kompleksnija u odnosu na dematerilalizaciju efektnih hartija od vrednosti zbog individualnih karakteristika svakog robnog zapisa. Kao rezultat ovoga, elektronski sistemi robnih zapisa su retki u svetu i u primeni su za samo nekoliko vrsta roba, poput pamuka i nekoliko vrsta žitarica. Ipak promena od papirnih hartija od vrednosti ka elektronskim u finansijskom sektoru, koja je počela pre nekoliko decenija, sada se intenzivira i u oblasti poljoprivrednih proizvoda. Analize u ovom radu pokazuju značajan uticaj elektronske evidencije robnih zapisa na povećanje sigurnosti sistema javnih skladišta i unapređenje trgovanja robnim zapisima. PR Projekat Ministarstva nauke Republike Srbije, br.III 46006

The Influence of Wagon Structure Part Shape Optimization on Ultimate Fatigue Strength

This study investigates how shape optimisation affects the ultimate fatigue strength of a mechanical part. The mechanical part chosen for this investigation is an axle guard of running gear elements of the Hccrrs 2x2 axle car-carrying wagon. The static and fatigue strength analysis procedure according to the UIC 517 standard and numerical methods have been applied. Material properties were determined experimentally and the necessary numerical calculations were performed by using the finite element method. The observed axle guard is exposed to low cycle fatigue. ε-N curves and material properties of the S355J2+N steel grade are obtained by combining theoretical formulae and a mathematical function. According to the obtained experimental and numerical results the number of cycles until failure for both shapes of axle guards is obtained

Serbian translation of the 20-item Toronto alexithymia scale: Psychometric properties and the new methodological approach in translating scales

Introduction Since inception of the alexithymia construct in 1970's, there has been a continuous effort to improve both its theoretical postulates and the clinical utility through development, standardization and validation of assessment scales. Objective The aim of this study was to validate the Serbian translation of the 20-item Toronto Alexithymia Scale (TAS-20) and to propose a new method of translation of scales with a property of temporal stability. Methods The scale was expertly translated by bilingual medical professionals and a linguist, and given to a sample of bilingual participants from the general population who completed both the English and the Serbian version of the scale one week apart. Results The findings showed that the Serbian version of the TAS-20 had a good internal consistency reliability regarding total scale (α=0.86), and acceptable reliability of the three factors (α=0.71-0.79). Conclusion The analysis confirmed the validity and consistency of the Serbian translation of the scale, with observed weakness of the factorial structure consistent with studies in other languages. The results also showed that the method of utilizing a self-control bilingual subject is a useful alternative to the back-translation method, particularly in cases of linguistically and structurally sensitive scales, or in cases where a larger sample is not available. This method, dubbed as 'forth-translation', could be used to translate psychometric scales measuring properties which have temporal stability over the period of at least several weeks