Ad hoc -reititysprotokollien hyödyntämismahdollisuudet tulevaisuuden taistelukentällä

Tulevaisuuden taistelukenttä tulee asettamaan useita haasteita asevoimille. Joukot liikkuvat enemmän ja nopeammin sekä sijaitsevat hajaantuneemmin taistelualueilla. Tilannetietoa pystytään tuottamaan kehittyneillä järjestelmillä, jolloin niiden siirtämiseen käytettyjen viestijärjestelmien pitää pystyä toimittamaan tätä kasvanutta informaation määrää. Ad hoc ja Mobile Ad Hoc Network (MANET) -verkoilla voidaan siirtää suuria määriä informaatiota tai dataa joukkojen välillä. Verkoissa käytetyt reititysprotokollat määrittävät miten lähetetty tieto liikkuu verkossa. Oikealla reititysprotokollan valinnalla pystytään vaikuttamaan verkon ruuhkautumiseen, tiedon siirtymisen varmuuteen, tiedonsiirtonopeuksiin, kaluston toimintakykyyn sekä siirtotien toimivuuteen. Päätutkimuskysymykseni on: Mitä käyttömahdollisuuksia AD HOC -reititysprotokollilla on tulevaisuuden taistelukentällä? Tutkimusta tukevat alakysymykset: Mitä viestillisiä vaatimuksia tulevaisuuden taistelukenttä voi asettaa MANET-verkolle? Mitä eroja erilaisilla ad hoc -reititysprotokollilla on? Mitä vaikutuksia erilaisilla siirtoteillä on MANET-verkossa? Tutkimukseen käytetty aineisto on kerätty internet- sekä kirjallisuuslähteistä. Lähteisiin sisältyy aihepiirin kuuluvia tutkimuksia, artikkeleita, oppaita ja yritysten tuote-esitelmiä. Johtopäätöksenä voidaan todeta, että taistelukentän muuttujat määrittävät parhaan käytettävän reititysprotokollan. Olennaisena tekijänä on hahmottaa verkkoa käyttävän joukon tarve sekä minkälaista dataa verkossa liikkuu. Erilaiset reititysprotokollat soveltuvat paremmin erilaisille joukoille ja erilaiseen toimintaympäristöön. Reititysprotokollaa valittaessa tulee huomioida käytössä olevat siirtotiet, jotta tiedonsiirtokaistaa ei tuhlata ja tällä tavalla ruuhkauteta verkkoa.

A survey of VANET technologies

Recent advancement in wireless communication technologies and automobiles have enabled the evolution of Intelligent Transport System (ITS) which addresses various vehicular traffic issues like traffic congestion, information dissemination, accident etc. Vehicular Ad-hoc Network (VANET) a distinctive class of Mobile ad-hoc Network (MANET) is an integral component of ITS in which moving vehicles are connected and communicate wirelessly. Wireless communication technologies play a vital role in supporting both Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication in VANET. This paper surveys some of the key vehicular wireless access technology standards such as 802.11p, P1609 protocols, Cellular System, CALM, MBWA, WiMAX, Microwave, Bluetooth and ZigBee which served as a base for supporting both Safety and Non Safety applications. It also analyses and compares the wireless standards using various parameters such as bandwidth, ease of use, upfront cost, maintenance, accessibility, signal coverage, signal interference and security. Finally, it discusses some of the issues associated with the interoperability among those protocols.

Limitations of trust management schemes in VANET and countermeasures

Vehicular networks ensure that the information received from any vehicle is promptly and correctly propagated to nearby vehicles, to prevent accidents. A crucial point is how to trust the information transmitted, when the neighboring vehicles are rapidly changing and moving in and out of range. Current trust management schemes for vehicular networks establish trust by voting on the decision received by several nodes, which might not be required for practical scenarios. It might just be enough to check the validity of incoming information. Due to the ephemeral nature of vehicular networks, reputation schemes for mobile ad hoc networks (MANETs) cannot be applied to vehicular ad hoc networks (VANET). We point out several limitations of trust management schemes for VANET. In particular, we identify the problem of information cascading and oversampling, which commonly arise in social networks. Oversampling is a situation in which a node observing two or more nodes, takes into consideration both their opinions equally without knowing that they might have influenced each other in decision making. We show that simple voting for decision making, leads to oversampling and gives incorrect results. We propose an algorithm to overcome this problem in VANET. This is the first paper which discusses the concept of cascading effect and oversampling effects to ad hoc networks. © 2011 IEEE.

Análise dos atendimentos do SAMU 192: componente móvel da Rede de Atenção às Urgências e Emergências

Pós-graduação em Enfermagem (mestrado profissional) - FMB

Subjective assessment of the impact of transmission errors in 3DTV compared to HDTV

Recently, broadcasted 3D video content has reached households with the first generation of 3DTV. However, few studies have been done to analyze the Quality of Experience (QoE) perceived by the end-users in this scenario. This paper studies the impact of trans- mission errors in 3DTV, considering that the video is delivered in side-by-side format over a conventional packet-based network. For this purpose, a novel evaluation methodology based on standard sin- gle stimulus methods and with the aim of keeping as close as pos- sible the home environment viewing conditions has been proposed. The effects of packet losses in monoscopic and stereoscopic videos are compared from the results of subjective assessment tests. Other aspects were also measured concerning 3D content as naturalness, sense of presence and visual fatigue. The results show that although the final perceived QoE is acceptable, some errors cause important binocular rivalry, and therefore, substantial visual discomfort.

Analysis of ad hoc routing protocols for emergency and rescue scenarios.

A mobile ad hoc network MANET is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or centralized administration. This makes it ideal for emergency and rescue scenarios where information sharing is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile ad hoc networks: proactive, reactive and hierarchical, have a better performance in such scenarios. Using a real urban area being set for the emergency and rescue scenario, we calculate the density of nodes and the mobility model needed for validation. The NS2 simulator has been used in our study. We also show that the hierarchical routing strategies are beffer suited for this type of scenarios.

Behavior of Ad Hoc routing protocols, analyzed for emergency and rescue scenarios, on a real urban area

A mobile Ad Hoc network (MANET) is a collection of wireless mobile nodes that can dynamically configure a network without a fixed infrastructure or central administration. This makes it ideal for emergency and rescue scenarios, where sharing information is essential and should occur as soon as possible. This article discusses which of the routing strategies for mobile MANETs: proactive, reactive or hierarchical, has a better performance in such scenarios. By selecting a real urban area for the emergency and rescue scenario, we calculated the density of nodes and the mobility model needed for the validation study of AODV, DSDV and CBRP in the routing model. The NS2 simulator has been used for our study. We also show that the hierarchical routing strategies are better suited for this type of scenarios.

Local densities orthogonal to beta-sheet amide planes: patterns of packing in globular proteins.

We have investigated the efficiency of packing by calculating intramolecular packing density above and below peptide planes of internal beta-pleated sheet residues in five globular proteins. The orientation of interest was chosen to allow study of regions that are approximately perpendicular to the faces of beta-pleated sheets. In these locations, nonbonded van der Waals packing interactions predominate over hydrogen bonding and solvent interactions. We observed considerable variability in packing densities within these regions, confirming that the interior packing of a protein does not result in uniform occupation of the available space. Patterns of fluctuation in packing density suggest that the regular backbone-to-backbone network of hydrogen bonds is not likely to be interrupted to maximize van der Waals interactions. However, high-density packing tends to occur toward the ends of beta-structure strands where hydrogen bonds are more likely to involve nonpolar side-chain groups or solvent molecules. These features result in internal protein folding with a central low-density core surrounded by a higher-density subsurface shell, consistent with our previous calculations regarding overall protein packing density.

Subjective quality evaluation for voice communication over MANET

Due to the dynamic and mutihop nature of the Mobile Ad-hoc Network (MANET), voice communication over MANET may encounter many challenges. We set up a subjective quality evaluation model using ITU-T E-model with extension. And through simulation in NS-2, we evaluate how the following factors impact voice quality in MANET: the number of hops, the number of route breakages, the number of communication pairs and the background traffic. Using AODV as the underlying routing protocol, and with the MAC layer changed from 802.11 DCF to 802.11e EDCF, we observe that 802.11e is more suitable for implementating voice communication over MANET. © 2005 IEEE.

Optical data transmission with fluctuating frequency offset and strong phase noise

We examine data transmission during the interval immediately after wavelength switching of a tunable laser and, through simulation, we demonstrate how choice of modulation format can improve the efficacy of an optical burst/packet switched network. © 2013 Optical Society of America.

Foundational Forensic Techniques for Cellular and Ad Hoc Multi-hop Networks

The Internet has become an integral part of our nation's critical socio-economic infrastructure. With its heightened use and growing complexity however, organizations are at greater risk of cyber crimes. To aid in the investigation of crimes committed on or via the Internet, a network forensics analysis tool pulls together needed digital evidence. It provides a platform for performing deep network analysis by capturing, recording and analyzing network events to find out the source of a security attack or other information security incidents. Existing network forensics work has been mostly focused on the Internet and fixed networks. But the exponential growth and use of wireless technologies, coupled with their unprecedented characteristics, necessitates the development of new network forensic analysis tools. This dissertation fostered the emergence of a new research field in cellular and ad-hoc network forensics. It was one of the first works to identify this problem and offer fundamental techniques and tools that laid the groundwork for future research. In particular, it introduced novel methods to record network incidents and report logged incidents. For recording incidents, location is considered essential to documenting network incidents. However, in network topology spaces, location cannot be measured due to absence of a 'distance metric'. Therefore, a novel solution was proposed to label locations of nodes within network topology spaces, and then to authenticate the identity of nodes in ad hoc environments. For reporting logged incidents, a novel technique based on Distributed Hash Tables (DHT) was adopted. Although the direct use of DHTs for reporting logged incidents would result in an uncontrollably recursive traffic, a new mechanism was introduced that overcome this recursive process. These logging and reporting techniques aided forensics over cellular and ad-hoc networks, which in turn increased their ability to track and trace attacks to their source. These techniques were a starting point for further research and development that would result in equipping future ad hoc networks with forensic components to complement existing security mechanisms.

Trazer a biblioteca no bolso: os serviços para dispositivos móveis nas bibliotecas académicas

Introdução – Os serviços de comunicação móvel para tablets, smartphones, e-book readers desenvolveram-se de forma extremamente rápida nos últimos anos assumindo-se como uma rede de aprendizagem privilegiada para os estudantes. Em 2012, 55% dos estudantes do ensino superior possuíam um smarthphone, 62% dispunham de um ipod e 21% tinham de um tablet. 67% usavam-nos em contexto académico. Objetivo – Apresentar de forma sucinta a resposta das bibliotecas de ensino superior ao crescimento da utilização dos dispositivos móveis e como é que os parceiros das bibliotecas, em especial os editores, estão a potenciar essa utilização. Métodos – A partir de uma seleção e análise de bibliografia sobre a temática realizou-se uma pesquisa na internet, nos sites de bibliotecas de ensino superior e nas páginas dos editores que permitisse aferir evidências. Resultados – Identificaram-se cinco serviços e 23 recursos. Discussão – Um primeiro serviço prende-se com a adaptação dos conteúdos dos websites das bibliotecas de forma a serem lidos por qualquer tipo de dispositivos. Outro serviço identificado foi a disponibilização do catálogo da biblioteca online tornando-o acessível aos dispositivos móveis, permitindo a pesquisa e a localização de informação, a reserva ou a renovação de documentos. Identificou-se o desenvolvimento de algumas coleções especificamente para os dispositivos móveis. Constatou-se a utilização de códigos QR para divulgar normas de funcionamento da biblioteca, recursos, o mapa, o contacto do serviço de referência e para geolocalização. Por fim verificou-se a utilização de SMS para informar os utilizadores sobre reservas, prazos de empréstimo, entre outras informações. O recurso mais comum na maioria dos sites analisados foi a disponibilização de uma versão do website para dispositivos móveis de que são exemplos a Cambridge Journals Online mobile, o EBSCOhost mobile, o SpringerLink, a OVIDToday, o UpToDate, a PubChase e a BrowZine. Com o objetivo de tornar os seus produtos acessíveis on-the go, oferecem inúmeras possibilidades, nomeadamente de pesquisa, de acesso a textos integrais, de elaboração de listas de interesse personalizadas, de leitura offline, entre outras que podemos encontrar na aplicação da EBSCOhost mobile, na JAMA Network, na OVIDToday, no portal de Periódicos CAPES ou na plataforma Ebrary da ProQuest. Em ferramentas como a UpToDate ou os aplicativos da Elsevier e da Micromedex é disponibilizada informação baseada na evidência e recomendações que podem ser aplicadas em consulta. Os gestores de referências bibliográficas como o Mendeley e o Zotero também acompanharam esta tendência e desenvolveram aplicações para dispositivos móveis. Para além disso funcionam de forma integrada com outras aplicações como a Browzine e a Pubchase. Conclusão – O recurso às tecnologias móveis é uma forma das bibliotecas manterem canais de comunicação com os utilizadores, mas embora existam muitas vantagens no uso das tecnologias móveis a implementação destes serviços implica um esforço financeiro e humano que nem todas as bibliotecas serão capazes de cumprir. Encontrar a forma de gerir este processo é o desafio que se impõe no futuro.

Mobility Management in Packet Switched Mobile Networks

Nykyisin matkaviestinverkot ovat osa jokapäiväistä elämää. Merkittävimpiä eroja kiinteiden ja matkaviestinverkkojen välillä on käyttäjän liikkuvuus, joka voidaan määritellä mahdollisuudeksi soittaa ja vastaanottaa puheluita missä ja milloin tahansa. Työ selittää termin liikkuvuus ja määrittää ongelmat, jotka täytyy ratkaista liikkuvuuden aikaansaamiseksi sekä tavat, joilla nämä ongelmat on ratkaistu matkaviestinverkoissa. Työ luo yleiskatsauksen liikkuvuuden aikaansaamisessa käytettäviin menetelmiin, joita ovat haku, sijainnin päivitys, sijainnin seuranta ja kanavan vaihto. Työ keskittyy liikkuvuuteen kolmannen sukupolven matkaviestinverkkojen paketti-kytkentäisessä osassa, esimerkkinä liikkuvuuden hallinta UMTS:ssa (Universal Mobile Telecommunications System). Erot paketti- ja piirikytkentäisen osan välillä tuodaan esille ja selitetään. Jotta käyttäjät ja heidän päätteensä voisivat liikkua, tiedon täytyy kulkea verkon eri osien välillä. Merkinanto verkkoelementtien välillä ja liikkuvuuden mahdollistavien toimenpiteiden suoritus tehdään yhteyskäytännön avulla. Työ kuvaa yhteyskäytännöt, jotka ovat osallisena liikkuvuuden tarjontaan. Painopiste on GPRS:n liikkuvuuden-hallintayhteyskäytännössä, GMM:ssä. GMM protokollan prototyypin toteutus on esitetty työn käytännön osassa.

IP Telephony in Third Generation Mobile Systems: Transport Layer Dimensioning

Tämä diplomityö käsittelee kolmannen sukupolven matkaviestinjärjestelmien kuljetuskerroksen mitoitusta. Nykyisten matkapuhelinverkkojen korvaajiksi suunnitellut kolmannen sukupolven matkaviestinjärjestelmät tulevat yhdistämään perinteisen puhelinviestinnän ja uudenlaiset datapalvelut. Uudet verkot tulevat perustumaan pakettivälitteiseen tiedonsiirtoon joka mahdollistaa molempien liikennetyyppien, puheen sekä datan, siirtämisen samassa verkossa. Tämän ratkaisun uskotaan tarjoavan paremmat mahdollisuudet uusien palvelujen luomiseen ja parantavan tiedonsiirtokapasiteettia. Siirtyminen pakettivälitteiseen tiedonsiirtoon aiheuttaa kuitenkin suuria muutoksia verkkoarkkitehtuurissa. Tässä diplomityössä tarkastellaan tulevien runkoverkkojen mitoitukseen liittyviä näkökohtia sekä muodostetaan alustavia kuljetuskerroksen mitoitusohjeita. Diplomityö on tehty osaksi diplomi-insinöörin tutkintoa Lappeenrannan teknillisessä korkeakoulussa. Työ on tehty Nokia Networksin palveluksessa Helsingissä, vuoden 2000 toisella puoliskolla.

Managing Packet Data (Sessions) in 3G Mobile Networks

Tällä hetkellä kolmannen sukupolven matkapuhelinjärjestelmät ovat siirtyneet kaupalliseen vaiheeseen. Universal Mobile Telecommunication System (UMTS) on eräs kolmannen sukupolven matkapuhelinjärjestelmä, jota tullaan käyttämään Euroopassa. Diplomityön päämääränä on tutkia, kuinka pakettivälitteistä tiedonsiirtoa hallitaan UMTS - verkoissa. Diplomityö antaa yleiskuvan toisen sukupolven matkapuhelinjärjestelmien datapalveluiden kehityksestä kolmannen sukupolven nopeisiin matkapuhelinjärjestelmiin. Pakettivälitteisen verkon verkkoarkkitehtuuri on esitetty sekä sen, diplomityön kannalta, tärkeimpien osien toiminnallisuus on selvitetty. Myös pakettipohjaisten datayhteyksien eli istuntojen muodostaminen ja vapauttaminen sekä aktiivisen yhteyden ominaisuuksien muokkaaminen on esitetty tässä diplomityössä. Yhteydenhallintaprotokolla, Session Management (SM), on yksi protokolla, joka osallistuu pakettidatayhteyden hallintaan. SM -protokolla on käsitelty työssä yksityiskohtaisesti. SM -protokollan SDL toteutus on esitetty diplomityön käytännönosassa