CHARACTERIZATION OF RF SIGNAL BEHAVIOR FOR THE USE IN INDOOR HUMAN PRESENCE DETECTION

ABSTRACT This paper presents a method or technique that identifies physical intrusion detection in an indoor environment that is based on received signal strength indicator (RSSI) on radio frequency identification. The objective of this paper is two folds. Firstly, is to characterize the signal behavior in an indoor environment using statistical measures. Secondly, is to identify the existence of a human presence inside a contained environment (e.g., room). The objective is to use simple means like the recorded readings of the received signal strength indicator (RSSI). The characterization was observed during three distinctive time intervals, namely; empty room, with human presence, and transitional period during link crossings. The experiment was repeatedly conducted for 5 minutes to validate the averaged results. In order to emulate real-life environment, experiments were conducted using Zigbee-compliant iris mote XM2110 and MIB510 programming boards with transmitter and receiver antennas, and interfaced using TinyOS software on Linux. Our results show that there are distinctive statistical features that can utilized as flags to classify the three cases stated above, empty room, occupied and link being crossed. These results motivate the design of alarm system to detect human presence using RSSI statistics only

Intrusion detection based on embedded processing of received signal strength indicator

Langattomien anturiverkkojen yhteydessä, vastaanotetun signaalin voimakkuuden indikaattoria (RSSI, received signal strength indicator) on perinteisesti käytetty langattomien anturien paikallistamiseen, etäisyyden estimointiin ja radiolinkin hyvyyden arviointiin. Viimeaikainen tutkimus on osoittanut, että RSSI:n vaiheluita voidaan käyttää myös havaitsemaan ihmisten läsnäolo langattoman anturiverkon läheisyydessä. Sen lisäksi ihmisen kulkema reitti valvotulla alueella voidaan uudelleen rakentaa antureiden keräämistä RSSI mittauksista. Tämä menettely on toimiva, mutta se vaatii kaikkien RSSI mittausten lähettämistä keskussolmulle erillistä prosessointia varten ja täten se kasvattaa anturiverkon latenssia ja energian kulutusta. Diplomityön tavoitteena on käyttää RSSI mittauksia sisätilojen valvontaa varten prosessoimalla mittaukset hajautetusti anturitasolla. Hajautetulla prosessoinnilla anturiverkon solmut kykenevät itsenäisesti havaitsemaan henkilön ja seuraamaan hänen liikkeitään. Lähettämällä keskussolmulle vain hälytykset jotka liittyvät merkittäviin tapahtumiin, järjestelmän latenssi sekä energiankulutus pystytyään minimoimaan. Lisäksi järjestelmän käyttämä tarkka aikasynkronointiprotokolla mahdollistaa solmujen pitämään radionsa suljettuna yli puolet ajasta kasvattaen järjestelmän elinikää entisestään. Kokeiden aikana, esitetty järjestelmä kykeni havaitsemaan valvotulle alueelle tunkeutuneen ihmisen ja seuraamaan hänen liikkeitään reaaliajassa. Järjestelmän mahdollisia sovelluskohteita ovat kriittisen rakennusten valvonta, työntekijöiden turvallisuuden lisääminen teollisuudessa, edesauttaa pelastustyöntekijöitä löytämään ihmiset esimerkiksi tulipaloissa ja maanjäristyksissä, sekä avustamaan poliiseja panttivankitilanteissa tai terroristihyökkäyksissä.In the context of wireless sensor networks (WSNs), the received signal strength indicator (RSSI) has been traditionally exploited for nodes localization, distance estimation, and link quality assessment. Recent research has shown that variations of the RSSI in indoor environments where nodes have been deployed can be exploited to detect movements of people. Moreover, the time-histories of the RSSI of multiple links allow reconstructing the path followed by the person inside the monitored area. This approach, though effective, requires the transmission of multiple raw RSSI time-histories to a central sink node for off-line analysis, consistently increasing latency and power consumption of the system. This thesis aims at applying distributed processing of the RSSI measurements for indoor surveillance purposes. Through distributed processing, the nodes are able to autonomous-ly detect and track a moving person, minimizing latency and power consumption of the system by transmitting to the sink node only the alerts raised by significant events. More-over, a high accuracy time synchronization protocol allows the nodes to keep the radio off for over half of the time, increasing the life time of the system. During the tests, the proposed system was able to detect the intrusion of a person walking inside the monitored area, and to correctly keep track in real-time of the path he had followed. Possible applications of such a system include surveillance of buildings, enhancement of workers safety in factories, support to emergency workers in locating people e.g. during fires and earthquakes, and to police in hostage situations or terrorist attacks

The influence of induced mutagenesis on reproductive behavior of Drosophila subobscura and the role of sexual selection in relationto the level of mutational load

Prema teorijskim očekivanjima seksualna selekcija može smanjivati mutaciona opterećenja u populacijama. Mužjaci koji su boljeg genetičkog kvaliteta bi trebalo da budu uspešniji u parenju u poređenju sa mužjacima lošijeg genetičkog kvaliteta. Na taj način ženke, prilikom izbora partnera za parenje, mogu da eliminišu one mužjake koji nose štetne alele, i da smanje mogućnost prenošenja štetnih alela u sledeću generaciju. Seksualna selekcija će redukovati mutaciona opterećenja i povećavati adaptivnu vrednost populacije, ako je većina mutacija štetna i za adaptivnu vrednost i za osobine koje utiču na uspešnost mužjaka u parenju. Istraživanja poslednjih godina su dala rezultate koji idu u prilog ovoj teoriji, ali i oprečne rezultate. Ovakva kontradiktornost proizilazi iz kompleksnosti problematike usled različitih reproduktivnih strategija vrsta, kao i različitih reproduktivnih strategija mužjaka i ženki. Takođe, osobine koje utiču na komponente adaptivne vrednosti, kao i na uspešnost u parenju, su veoma složene, pod determinacijom velikog broja gena, i u čijoj osnovi leže kompleksne genske interakcije. Iako se kao osobine koje su cilj seksualne selekcije najčešće analiziraju sekundarne polne karakteristike, i mnoge druge osobine određuju atraktivnost mužjaka. To su i morfološke, fiziološke, ponašajne i druge osobine koje utiču na uspešnost u parenju, a mogu se nazvati osobinama koje su zavisne od opšteg stanja mužjaka (eng. condition-dependent traits)...According to theoretical predictions sexual selection can reduce mutational load in populations. Males of good genetic quality should be more successful in matings, compared to the males of low genetic quality. In this way females, through the choice of mating partners, can eliminate males carriers of deleterious alleles, and reduce transmission of deleterious alleles to the next generation. Sexual selection will purge mutational load and increase fitness if most mutations were deleterious to both nonsexual fitness and condition-dependent traits affecting mating success. Studies in recent years have yielded results that support this theory, but opposite results are obtained, as well. This contradiction arises from different reproductive strategies of species, and different reproductive strategies of males and females. Traits that affect fitness components, as well as mating success, are under polygenic determination, with very complex gene interactions. Although secondary sexual traits were usually analyzed as target of sexual selection, many other traits can determine male attractiveness. Traits such as morphological, physiological, behavior and other, affecting mating success, can be termed as condition-dependent traits. In order to test this hypothesis, that sexual selection can reduce mutational load, two experimental groups were formed from the same population genetic pool of Drosophila subobscura, which differed in the level of mutational load. Mutations were induced in one group, using 30Gy ionizing radiation. The effect of sexual selection in reduction of mutational load was measured through different components of male mating behavior (courtship occurrence, courtship latency, courtship intensity, mating occurrence,latency to mating and duration of mating)...