Analysis of Radar Doppler Signature from Human Data

This paper presents the results of time (autocorrelation) and time-frequency (spectrogram) analyses of radar signals returned from the moving human targets. When a radar signal falls on the human target which is moving toward or away from the radar, the signals reflected from different parts of his body produce a Doppler shift that is proportional to the velocity of those parts. Moving parts of the body causes the characteristic Doppler signature. The main contribution comes from the torso which causes the central Doppler frequency of target. The motion of arms and legs induces modulation on the returned radar signal and generates sidebands around the central Doppler frequency, referred to as micro-Doppler signatures. Through analyses on experimental data it was demonstrated that the human motion signature extraction is better using spectrogram. While the central Doppler frequency can be determined using the autocorrelation and the spectrogram, the extraction of the fundamental cadence frequency using the autocorrelation is unreliable when the target is in the clutter presence. It was shown that the fundamental cadence frequency increases with increasing dynamic movement of people and simultaneously the possibility of its extraction is proportional to the degree of synchronization movements of persons in the group

Scardinius knezevici Bianco & Kottelat, 2005 and Alburnus scoranza Bonaparte, 1845: New species of ichthyofauna of Serbia and the Danube basin

Research into the ichthyofauna of the Vlasina Lake reservoir in south Serbia, which is part of the Danube basin, was carried out in 1993, 40 years after its formation. The results of the research reveal the presence of several species of fish belonging to the Adriatic and Aegean basin, such as Alburnus albidus, Rutilus basak, Scardinius graecus and Pachychilon macedonicus. These findings are of great importance from the aspect of conservation, because the species Scardinius graecus and Alburnus albidus are on the European list of endangered fish species. In the latest study of the Vlasina Lake reservoir ichthyofauna (70 years after its formation), the above-mentioned species were not found. However, the presence of naturalized populations of two species from the Adriatic basin were confirmed: Scardinius knezevici and Alburnus scoranza. These findings represent the first known areal expansion of these species, which are new to the ichthyofauna of Serbia, from the Adriatic into the Danube (Black Sea) basin.[Acknowledgments. The present work was supported by the Ministry of Education and Science of the Republic of Serbia (Projects No. 43002 and 173025).

LTE in Unlicensed Bands is neither Friend nor Foe to Wi-Fi

Proponents of deploying LTE in the 5 GHz band for providing additional cellular network capacity have claimed that LTE would be a better neighbour to Wi-Fi in the unlicensed band, than Wi-Fi is to itself. On the other side of the debate, the Wi-Fi community has objected that LTE would be highly detrimental to Wi-Fi network performance. However, there is a lack of transparent and systematic engineering evidence supporting the contradicting claims of the two camps, which is essential for ascertaining whether regulatory intervention is in fact required to protect the Wi-Fi incumbent from the new LTE entrant. To this end, we present a comprehensive coexistence study of Wi-Fi and LTE-in-unlicensed, surveying a large parameter space of coexistence mechanisms and a range of representative network densities and deployment scenarios. Our results show that, typically, harmonious coexistence between Wi-Fi and LTE is ensured by the large number of 5 GHz channels. For the worst-case scenario of forced co-channel operation, LTE is sometimes a better neighbour to Wi-Fi - when effective node density is low - but sometimes worse - when density is high. We find that distributed interference coordination is only necessary to prevent a "tragedy of the commons" in regimes where interference is very likely. We also show that in practice it does not make a difference to the incumbent what kind of coexistence mechanism is added to LTE-in-unlicensed, as long as one is in place. We therefore conclude that LTE is neither friend nor foe to Wi-Fi in the unlicensed bands in general. We submit that the systematic engineering analysis exemplified by our case study is a best-practice approach for supporting evidence-based rulemaking by the regulator.Comment: accepted for publication in IEEE Acces

Mehanizmi reparacije kod ozračenih stanica

Many aspects of bacterial mutations which lead to enhanced sensitivity to UV and X radiations have been studied. Radiosensitivity appears to result from a loss of the capacity to repair damaged DNA. The genetic map of these mutations in the chromosome of E. coli is shown. Sofar the best known DNA repair mechanisms are by excision repair (excision of pyrimidine dimers controlled by nonlinked uvr genes) and by recombination repair (elimination of similar damage as a result of genetic recombination between undamaged regions of the DNA). The understanding of the lethal and mutagenic effects of radiation on cells rests on the quantitative and qualitative identification of the various lesions in the DNA. Exposure to UV irradiation causes the production of many different types of photoproducts, but pyrimidine dimers appear to be the most important damage causing biological inactivation. The study of biochemical defects of UV sensitive mutants has allowed a partial understanding of the repair mechanisms. Generally, they consist in removing the UV induced-pyrimidine dimers by cellular enzyme systems (monomerization through photoreactivation, excision or recombination by the action of endo and exonucleases, polymerases and polynucleotides ligases). The X-ray induced lesions arc very heterogenous and not yet as well defined and the mechanisms of recovery are far less understood than in the case of U. V.Mnogi aspekti mutacija koje vode povećanoj osjetljivosti na UV i X zračenje izučavani su u Escherichia coli i u velikom broju slučajeva povećanje osjetljivosti je smatrano kao gubitak kapaciteta za reparaciju DNK. Predstavljena je genetska karta ovih mutacija na kromosomu E. coli. Da bi se shvatio mehanizam biološkog učinka zračenja na živu stanicu, neophodno je dovesti u vezu kvalitativno i kvantitativno oštećenje DNK. Nakon zračenja UV, u zavisnosti od eksperimetalnih uvjeta i fizikalnog stanja DNK, otkriveni su različiti tipovi fotoprodukata. Dokazano je da je među ovim lezijama fotoprodukt pirimidinski dimer značajan u biološkoj inaktivaciji. Mehanizmi reparacije u stanicama koje sadrže enzime potrebne za ovaj proces, dovode do uklanjanja ovog fotoprodukta (»brisanje«) pa uslijed toga i do povećanog preživljavanja. Za razliku od oštećenja induciranih zračenjem UV, oštećenja inducirana jonizirajućim zračenjem su ne samo veoma heterogena već i velikim dijelom neidentificirana. Sudeći po mnogim rezultatima moglo bi se reći da letalno oštećenje nastaje zbog diskontinuiteta genoma prouzrokovanog jonizujućim zračenjem. Iznijeti su također radovi koji izučavaju biokemijske defekte mutanata koji su osjetljivi na UV zračenje, što dovodi do djelomičnog shvatanja mehanizma reparacije DNK. Ovaj mehanizam uključuje fotorestauraciju ("brisanje" lezije dimer pirimidina, monomerizacijom dimer pirimidina) i restauraciju (rekonstrukcija oštećenih regiona DNK uslijed procesa isijecanja (ekscizije) dimer pirimidina i reparativne sinteze DNK. Reparacija nakon X zračenja samo je djelomično shvaćena i odnosi se na uspostavljanje kontinuiteta DNK u jednom od lanaca dvolančane DNK. Postoje indikacije da restauracija pomoću isijecanja sinteze DNK (replikacije) i rekombinacije može biti uvjetovana enzimskim kompleksima. Letalne radiolezije razmatrane su u svjetlosti mehanizma reparacije

Risk-Informed Interference Assessment for Shared Spectrum Bands: A Wi-Fi/LTE Coexistence Case Study

Interference evaluation is crucial when deciding whether and how wireless technologies should operate. In this paper we demonstrate the benefit of risk-informed interference assessment to aid spectrum regulators in making decisions, and to readily convey engineering insight. Our contributions are: we apply, for the first time, risk assessment to a problem of inter-technology spectrum sharing, i.e. Wi-Fi/LTE in the 5 GHz unlicensed band, and we demonstrate that this method comprehensively quantifies the interference impact. We perform simulations with our newly publicly-available tool and we consider throughput degradation and fairness metrics to assess the risk for different network densities, numbers of channels, and deployment scenarios. Our results show that no regulatory intervention is needed to ensure harmonious technical Wi-Fi/LTE coexistence: for the typically large number of channels available in the 5 GHz band, the risk for Wi-Fi from LTE is negligible, rendering policy and engineering concerns largely moot. As an engineering insight, Wi-Fi coexists better with itself in dense, but better with LTE, in sparse deployments. Also, both main LTE-in-unlicensed variants coexist well with Wi-Fi in general. For LTE intra-technology inter-operator coexistence, both variants typically coexist well in the 5 GHz band, but for dense deployments, implementing listen-before-talk causes less interference

Analysis of diet of piscivorous fishes in Bovan, Gruža and Šumarice Reservoir, Serbia

Diet of adult pikeperch Sander lucioperca, Eurasian perch Perca fluviatilis, northern pike Esox lucius and European catfish Silurus glanis as top predators in aquatic ecosystems in Serbia was investigated during 2011, in order to understand their relationship to their prey and to investigate their food consumption, feeding and assimilation rate, cannibalism, and habitat segregation. Northern pike, Eurasian perch, pikeperch and European catfish were collected in three reservoirs in Serbia. Prey items that were found in all four species included fish, mollusks, insect larvae and crustaceans. A total of 11 taxonomic groups were found, but they were not all represented as a prey in all four species. Eurasian perch were present in the diet of all four predatory fish species, mollusks were recorded only in that of European catfish. Roach Rutilus rutilus and bleak Alburnus alburnus were prey to all species, except northern pike. Chub Squalius cephalus, bream Brama brama and Gammaridae were found only in stomach of pikeperch. Analysis of similarity showed that difference for diet between predatory fish species was significant for their due to significant differences existing between northern pike and pikeperch and northern pike and Eurasian perch

New record of endangered red alga Bangia atropurpurea (A. Roth) C. Aardh (Bangiales, Rhodophyta) in the Nišava River, Serbia

Bangia atropurpurea was found at two new localities in the Nišava River (Southern Serbia). In Serbia, this species is endangered. It has been found so far in the Trgoviški Timok River, the Gvozdovačka River and the Raška River. With the two new localities in the Nišava River, at present Bangia occupies four rivers (five localities). New findings are important for the protection of the biodiversity of red algal flora in the region, and provide useful information on the ecological preferences of the species in Serbia

Results of investigating the macroinvertebrate community of the Danube River on the sector upstream from the Iron Gate (km 1083-1071)

The present work cites results of investigating aquatic macroinvertebrates of the Danube River on the sector upstream from the Iron Gate (KM 1083-1071). The investigated part is interesting from the hydrobiological standpoint above all due to differences of faunal composition in relation to higher sections that could be expected in view of differences in overall characteristics of the river. A rich macroinvertebrate community (84 taxa) was observed. The diversity of taxa is primarily a result of habitat diversity within the given stretch. Oligochaeta and Mollusca were the principal components

Neurobiological explanation of consciousness

Glavni cilj ovog rada jeste formulisanje modela svesti koji bi uspeo da prevaziđe prigovore i probleme sa kojim su se suočavali svi dosadašnji neurobiološki modeli. Najveći izazov je odgovor na pitanje kako je moguće da neki materijalni sistem, poput mozga, proizvede subjektivno iskustvo. Kao što ću pokazati, odgovor se nalazi u načinu na koji je mozak organizovan i njegovoj sposobnosti da proizvede posebnu vrstu kauzalnih interakcija (neprekidnu kauzalnu samoreferencu). Model svesti koji predlažem se oslanja na dinamičke modele prema kojima je svest globalno sistemsko svojstvo. Prema hipotezi neprekidne kauzalne samoreference koju ću zastupati, organizacija ima nesvodivu ulogu u stvaranju novih svojstava. Svest se ne može u potpunosti objasniti svođenjem na osnovne materijalne konstituente, već je ona suštinski relaciono svojstvo tih konstituenata. Objašnjenje svesti ne možemo naći u pojedinačnim gradivnim jedinicama mozga, neuronima, već u načinu na koji su oni organizovani. Istraživanja (Bressler and Kelso, 2016) (Tognoli and Kelso, 2014) (Kelso, 2012) pokazuju da postoje svojstva koja se nalaze na nivou celog sistema, koja proizilaze iz relacija među konstituentima a koja se ne mogu pronaći na nivou bazičnih konstituenata. Svest je dinamički proces, neprekidno menjajuća struktura kauzalnih relacija među konstituentima sistema. U skladu sa tim pokušaću da pokažem da se svest kao svojstvo pojavljuje u slučajevima kada materija i relacije između njenih elemenata imaju posebnu kauzalnu konfiguraciju. Kao glavnu teorijsku i empirijsku podršku toj hipotezi koristiću modele i eksperimentalnu evidenciju različitih autora koji zastupaju dinamičke teorije svesti poput Tononija, Edelmana, Spornsa i drugih. Navedeni autori implicitno podržavaju ontologiju u kojoj relacije spadaju u osnovna primitivna svojstva stvarnosti. (Sporns, Chialvo, Kaiser and Hilgetag, 2004) (Edelman and Tononi, 2000) (Olaf Sporns, 2010) (Tononi and Koch, 2015). U prvom poglavlju ću pokazati kakav je uticaj teorija dinamičkih sistema imala na druge nauke i koliko je uticala na promenu ontoloških pretpostavki. Ukazaću na važnost teorije dinamičkih sistema u argumentima u debati između redukcionizma i emergentizma. Kroz debatu između dva suprotstavljena stanovišta videćemo kako se fokus u razumevanju fizičkog sveta, pre svega funkcionisanja sistema, pomerio sa delova (mikro nivo) na celinu (makro nivo). U ovom poglavlju ćemo kroz različite teorijske hipoteze i empirijske primere videti da je teorija dinamičkih sistema osnov za prihvatanje savremene forme emergentizma, koja je od suštinske važnosti za uspostavljanje i odbranu teze prema kojoj je svest emergentno svojstvo u dinamičkim sistemima. Drugo poglavlje će fokus istraživanja staviti na teorijske okvire i osnovne pojmove teorije dinamičkih sistema. Pojmovi kojima raspolaže teorija dinamičkih sistema poput samoorganizujuće kritičnosti, metastabilnosti, tranzicije faza, emergencije, integracije i informacije su od suštinske važnosti za objašnjenje ponašanja kompleksnih sistema u koje spada i mozak. Kakva je empirijska primena ovih pojmova biće predstavljeno kroz analizu ponašanja gomile peska, zemljotresa, feromagnetnih materijala i kompjuterski model „Game of Life“. Navedeni primeri će imati poseban doprinos u odgovoru na pitanje kako jedan fizički sistem može da poseduje emergentno svojstvo koje prevazilazi ponašanje njegovih pojedinačnih elemenata. U ovom poglavlju načiniću i korak dalje pa ću pokazati koje su osobine mozga koje mu omogućavaju da proizvede emergentno svojstvo (svest). Kroz mnogobrojne primere iz kliničke prakse i simulacije pokazaću koliko je svesno iskustvo povezano sa sposobnošću sistema da integriše velike količine informacije. Kao što ćemo videti, sposobnost integracije velike količine informacije je posledica posebne arhitekture i funkcionalne dinamike mozga i upravo zahvaljujući njima mozak može da proizvede svesno iskustvo. U trećem poglavlju predstaviću najvažnije modele svesti koje se oslanjaju na teoriju dinamičkih sistema. Prvo ćemo videti modele koje svoje hipoteze zasnivaju na procesu integracije informacije (teorija dinamičkog jezgra, teorija integrisane informacije). Nakon toga ćemo videti kako se kompleksna dinamika polja može dovesti u vezu sa svesnim iskustvom. U okviru teorije polja će biti prikazani i modeli koji koriste pojam informacije da bi objasnili svesno iskustvo, ali treba imati na umu da takvi modeli informaciju koriste u kontekstu teorije polja. Na kraju ovog poglavlja će biti predstavljena teza proširene svesti koja dovodi u pitanje prostorno vremenske okvire u kojima se realizuje svesno iskustvo. U četvrtom poglavlju ću izložiti slabosti predloženih modela, pokazati njihovu nepotpunost i izložiti dodatne argumente kojima bi se otklonili problemi i dao potpuniji dinamički model svesti. Pokazaću da nijedan od navedenih dinamičkih modela svesti nije uzeo u obzir fundamentalnu osobinu fenomenalnog iskustva, usmerenost na samu sebe (samoreferentnost). Izložiću svoju osnovnu hipotezu koju sam nazvao „neprekidna kauzalna samoreferenca“ a koja se zasniva na procesu cirkularne kauzalnosti. Prema modelu koji ja zastupam subjektivno iskustvo je proces u kome dolazi do balansa kauzalnog uticaja između top down kauzalnosti koju sprovode elektromagnetna polja unutar mozga i bottom up kauzalnosti koju sprovode pojedinačni neuroni kroz svoje pražnjenje. Pokazaću da je glavni mehanizam svesti cirkularna kauzalna petlja koja se ostvaruje u talamokortikalnom sistemu gde dolazi do uspostavljanja kauzalne samoreference. Na samom kraju ćemo kroz nekoliko empirijskih primera testirati predviđanja HNKS i pokazati da ona bolje od ostalih prikazanih modela odgovara na svakodnevno shvatanje pojma svesti. Dakle, da bismo objasnili svest potrebno je da objasnimo kako je moguće da materijalni sistem proizvede fenomenalnu svest, egzistenciju doživljenu iz perspektive prvog lica. U pokušaju da odgovorim na ovo pitanje pošao sam od fenomenološke činjenice, da je svest uvek usmerena na samu sebe, da je subjektivno iskustvo uvek „zaključano“. Mi nikada ne možemo izaći van njega i pristupiti objektivnoj stvarnosti. Svesno iskustvo je uvek usmereno na sopstvene sadržaje. Pojam samoreferentnosti sam iskoristio za formulisanje hipoteze „neprekidne kauzalne samoreference“ koja nam pruža objašnjenje moždanih kauzalnih mehanizama koji stoje u osnovi svesti. Kako nijedan dinamički model do sada nije na zadovoljavajući način iskoristio tu činjenicu, smatram da predložena hipoteza predstavlja unapređenu verziju dosadašnjih dinamičih modelaThe main goal of this paper is to formulate a model of consciousness that would overcome the objections and problems faced by all neurobiological models to date. The biggest challenge is answering the question of how it is possible for a material system, such as the brain, to produce subjective experience. As I will show, the answer lies in the way the brain is organized and its ability to produce a special kind of causal interactions (continuous causal self-reference). The model of consciousness I propose relies on the dynamic models according to which consciousness is a global property of the system. According to the hypothesis of continuous causal self-reference that I will present, organization plays an irreducible role in creating new properties. Consciousness cannot be fully explained by reduction to basic material constituents, but it is rather essentially a relational property of those constituents. We cannot find an explanation of consciousness in the individual building blocks of the brain, neurons. It is in the way they are organized. Research (Bressler and Kelso, 2016) (Tognoli and Kelso, 2014) (Kelso, 2012) shows that there are properties that can be found on the level of the system as a whole, that arise from relationships among constituents, but that cannot be found at the level of basic constituents. Consciousness is a dynamic process, a constantly changing structure of causal relations between the constituents of a system. Accordingly, I will try to show that consciousness as a property occurs in cases where matter and the relations between its elements have a special causal configuration. As the main theoretical and empirical support for this hypothesis, I will use models and experimental record of various authors representing dynamic theories of consciousness such as Tononi, Edelman, Sporns and others. Listed authors implicitly support the ontology in which relations belong to the basic primitive properties of reality. (Sporns, Chialvo, Kaiser and Hilgetag, 2004) (Edelman and Tononi, 2000) (Olaf Sporns, 2010) (Tononi and Koch, 2015). In the first chapter, I will show what impact the theory of dynamical systems has had on other sciences and how much it influenced the change in ontological assumptions. I will point out the importance of the theory of dynamic systems in the arguments from the debate between reductionism and emergentism. Through the debate between the two opposing viewpoints we will see how the focus has shifted from the parts... to the whole... in the understanding of the physical world, above all of the functioning of the system. In this chapter, through various theoretical hypotheses and empirical examples, we will see that the theory of dynamical systems is the basis for adopting the contemporary form of emergentism, which is essential for establishing and defending the thesis that consciousness is an emergent property in dynamic systems. The second chapter will focus on the research on theoretical frameworks and basic concepts of the dynamical systems theory. Concepts in the theory of dynamic systems such as self-organizing criticality, metastability, phase transition, emergence, integration and information are essential for explanation of the behavior of complex systems, including the brain. Empirical application of these terms will be presented through an analysis of the behavior of sand piles, earthquakes, ferromagnetic materials and the computer model of the “Game of Life“. The examples mentioned above will give a special contribution to answering the question of how a physical system can have an emergent property that goes beyond the behavior of its elements. In this chapter, I will make a step further and show what are the characteristics of the brain that enable it to produce an emergent property (consciousness). Through numerous examples from clinical practice and simulation, I will demonstrate how conscious experience is related to the ability of the system to integrate a large quantity of information. As we shall see, the ability to integrate a large quantity of information is a result of the unique architecture and functional dynamics of the brain and due precisely to them the brain can produce conscious experience. In the third chapter, I will present the most important models of consciousness that rely on the theory of dynamical systems. We will first see the models that base their hypotheses on the process of information integration (Dynamic Core Theory, Integrated Information Theory). We will then see how complex field dynamics can be related to conscious experience. Within the field theory, models that take the notion of information to explain conscious experience, but which use information in the context of field theory, will also be shown. Field theory will also include models that use the notion of information to explain conscious experience, but we should have in mind that such models use information in the context of field theory. At the end of this chapter, the theses of extended consciousness that question the spatio-temporal boundaries in which conscious experience is realized will be presented. In the fourth chapter, I will outline the weaknesses of the proposed models, demonstrate their incompleteness, and present additional arguments to solve the problems and provide a more complete dynamic model of consciousness. I will show that none of these dynamic models of consciousness have taken into account the fundamental feature of phenomenal experience, self-directedness (self-referentiality). I will present my basic hypothesis, which I have called "continuous causal self-reference", which is based on the process of circular causality. According to the model that I am presenting, subjective experience is a process in which there is a balance of causal influence between top-down causality carried out by electromagnetic fields inside of the brain and a bottom-up causality carried out by firing of the single neurons. I will show that the main mechanism of the consciousness is the circular causal loop which is realized inside of the thalamocortical system, where causal self-reference is established. At the very end, through several empirical examples, we will test the predictions of HCCS and show that it fits the everyday understanding of the notion of consciousness better than other models presented. Hence, in order to explain consciousness, we need to explain how it is possible for the material system to produce phenomenal consciousness, existence experienced from a first-person perspective. In an attempt to answer this question, I started from the phenomenological fact that consciousness is always self-directed, that subjective experience is always "locked". We can never go beyond it and approach objective reality. A conscious experience is always focused on its own content. I used the term self-referentiality to formulate the hypothesis of “continuous causal self-reference” that provides us with an explanation of the brain’s causal mechanisms underlying consciousness. As no dynamic model has satisfactorily exploited this fact, I believe that the proposed hypothesis represents an advanced version of the dynamic models so fa