To see the other types of publications on this topic, follow the link: Heterogenous information network.
Dissertations / Theses on the topic 'Heterogenous information network'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Heterogenous information network.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Zhang, Jianjun. "Efficient Information Dissemination in Wide Area Heterogeneous Overlay Networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/16129.
Full textAbstract:
In this dissertation research we study and address the unique challenges involved in information sharing and dissemination of large-scale group communication applications. We focus on system architectures and various techniques for efficient and scalable information dissemination in distributed P2P environments. Our solutions are developed by targeting at utilizing three representative P2P overlay networks: structured P2P network based on consistent hashing techniques, unstructured Gnutella-like P2P network, and P2P GeoGrid based on geographical location and proximity of end nodes. We have made three unique contributions to the general field of large-scale information sharing and dissemination. First, we propose a landmark-based peer clustering techniques to grouping end-system nodes by their network proximity, and a communication management technique addresses load balancing and reliability of group communication applications in structured P2P network. Second, we develop a utility-based P2P group communication service middleware, consisting of a utility-based topology management and a utility-aware P2P routing, for providing scalable and efficient group communication services in an unstructured P2P overlay network of heterogeneous peers. Third, we propose an overlay network management protocol that is aware of the geographical location of end-system nodes and a set of routing and adaptation techniques, aiming at building decentralized information dissemination service networks to support location-based applications and services.
Although different overlay networks require different system designs for building scalable and efficient information dissemination services, we have employed two common design philosophies: (1) exploiting end-system heterogeneity and (2) utilizing proximity information of end-system nodes to localize most of the communication traffic, and (3) using randomized shortcuts to accelerate long-distant communications. We have demonstrated our design philosophies and the performance improvements in the above three types of P2P overlay networks. Concretely, by assigning more workloads to more powerful peers, we can greatly increase the system scalability and reduce the variation of workload distribution. By clustering end-system nodes based on their IP-network proximity or their geographical proximity, and utilizing randomized shortcuts, we can reduce the end-to-end communication latency, balance peer workloads against service request hotspots across the overlay network, and significantly enhance the scalability and efficiency of large-scale decentralized information dissemination and group communication.
2
Andersson, Karl. "On access network selection models and mobility support in heterogeneous wireless networks." Doctoral thesis, Luleå tekniska universitet, Datavetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18402.
Full textAbstract:
The aim of this thesis is to define a solution offering end-users seamless mobility in a multi-radio access technology environment. Today an increasing portion of cell phones and PDAs have more than one radio access technology and wireless access networks of various types are commonly available with overlapping coverage. This creates a heterogeneous network environment in which mobile devices can use several networks in parallel. In such environment the device needs to select the best network for each application to use available networks wisely. Selecting the best network for individual applications constitutes a major core problem.The thesis proposes a host-based solution for access network selection in heterogeneous wireless networking environments. Host-based solutions use only information available in mobile devices and are independent of information available in the networks to which these devices are attached. The host-based decision mechanism proposed in this thesis takes a number of constraints into account including network characteristics and mobility patterns in terms of movement speed of the user. The thesis also proposes a solution for network-based mobility management contrasting the other proposals using a host-based approach. Finally, this thesis proposes an architecture supporting mobility for roaming users in heterogeneous environments avoiding the need for scanning the medium when performing vertical handovers.Results include reduced handover latencies achieved by allowing hosts to use multihoming, bandwidth savings on the wireless interface by removing the tunneling overhead, and handover guidance through the usage of directory-based solutions instead of scanning the medium. User-perceived quality of voice calls measured on the MOS (Mean Opinion Score) scale shows no or very little impact from the mobility support procedures proposed in this thesis. Results also include simulation models, real-world prototypes, and testbeds that all could be used in future work. The proposed solutions in this thesis are mainly evaluated using simulations and experiments with prototypes in live testbeds. Analytical methods are used to complement some results from simulations and experiments<br>Godkänd; 2010; 20100811 (karand); DISPUTATION Ämnesområde: Mobila system/Mobile Systems Opponent: Universitetslektor, docent Marcus Fiedler, Blekinge tekniska högskola Ordförande: Universitetslektor, docent Christer Åhlund, Luleå tekniska universitet Tid: Fredag den 12 november 2010, kl 11.00 Plats: A1514 Demostudion, Luleå tekniska universitet
3
Köhler, Fredrik. "Network Virtualization in Multi-hop Heterogeneous Architecture." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-38696.
Full textAbstract:
Software Defined Networking is a technology that introduces modular and programmable networks that uses separated control- and data-planes. Traditional networks use mostly proprietary protocols and devices that needs to communicate with each other and share information about routes and paths in the network. SDN on the other hand uses a controller that communicates with devices through an open source protocol called OpenFlow. The routing rules of flows can be inserted into the networking devices by the controller. This technology is still new and it requires more research to provide evidence that it can perform better, or at least as good as, the conventional networks. By doing some experiments on different topologies, this thesis aims at discovering how delays of flows are affected by having OpenFlow in the network, and identifying overhead of using such technology. The results show that, the overhead can be to large for time and noise sensitive applications and average delay is comparable to conventional networks.
4
Bhatia, Vishal. "Remote programming for heterogeneous sensor networks." Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1091.
Full text
5
Oliveira, Talmai B. "Dealing with Uncertainty and Conflicting Information in Heterogeneous Wireless Networks." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352490436.
Full text
6
Toledo, Testa Juan Ignacio. "Information extraction from heterogeneous handwritten documents." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667388.
Full textAbstract:
L’objectiu d’aquesta tesi és l’extracció d’Informació de documents total o parcialment manuscrits amb una certa estructura. Bàsicament treballem amb dos escenaris d’aplicació diferent. El primer escenari són els documents moderns altament estructurats, com formularis. En aquests documents, la informació semàntica està ja definida en camps, amb una posició concreta al document i l’extracció de la informació és equivalent a una transcripció. El segon escenari son els documents semi-estructurats totalment manuscrits on, a més de transcriure, cal associar un valor semàntic, d’entre un conjunt conegut de valors possibles, a les paraules que es transcriuen.
En ambdós casos la qualitat de la transcripció té un gran pes en la precisió del sistema, per això proposem models basats en xarxes neuronals per a transcriure text manuscrit. Per a poder afrontar el repte dels documents semi-estructurats hem generat un benchmark, compost de dataset, una sèrie de tasques definides i una mètrica que es va presentar a la comunitat científica com a una competició internacional. També proposem diferents models basats en Xarxes Neuronals Convolucionals i recurrents, capaços de transcriure i assignar diferent etiquetes semàntiques a cada paraula manuscrita, és a dir, capaços d'extreure informació.<br>El objetivo de esta tesis es la extracción de Información de documentos total o parcialmente manuscritos, con una cierta estructura. Básicamente trabajamos con dos escenarios de aplicación diferentes. El primer escenario son los documentos modernos altamente estructurados, como los formularios. En estos documentos, la información semántica está pre-definida en campos con una posición concreta en el documento i la extracción de información es equivalente a una transcripción. El segundo escenario son los documentos semi-estructurados totalmente manuscritos, donde, además de transcribir, es necesario asociar un valor semántico, de entre un conjunto conocido de valores posibles, a las palabras manuscritas.
En ambos casos, la calidad de la transcripción tiene un gran peso en la precisión del sistema. Por ese motivo proponemos modelos basados en redes neuronales para transcribir el texto manuscrito. Para poder afrontar el reto de los documentos semi-estructurados, hemos generado un benchmark, compuesto de dataset, una serie de tareas y una métrica que fue presentado a la comunidad científica a modo de competición internacional. También proponemos diferentes modelos basados en Redes Neuronales Convolucionales y Recurrentes, capaces de transcribir y asignar diferentes etiquetas semánticas a cada palabra manuscrita, es decir, capaces de extraer información.<br>The goal of this thesis is information Extraction from totally or partially handwritten documents. Basically we are dealing with two different application scenarios. The first scenario are modern highly structured documents like forms. In this kind of documents, the semantic information is encoded in different fields with a pre-defined location in the document, therefore, information extraction becomes equivalent to transcription. The second application scenario are loosely structured totally handwritten documents, besides transcribing them, we need to assign a semantic label, from a set of known values to the handwritten words.
In both scenarios, transcription is an important part of the information extraction. For that reason in this thesis we present two methods based on Neural Networks, to transcribe handwritten text.In order to tackle the challenge of loosely structured documents, we have produced a benchmark, consisting of a dataset, a defined set of tasks and a metric, that was presented to the community as an international competition. Also, we propose different models based on Convolutional and Recurrent neural networks that are able to transcribe and assign different semantic labels to each handwritten words, that is, able to perform Information Extraction.
7
Razzaghi, Kouchaksaraei Hadi [Verfasser]. "Orchestrating network services using multi-domain, heterogeneous resources / Hadi Razzaghi Kouchaksaraei." Paderborn : Universitätsbibliothek, 2020. http://d-nb.info/1222587939/34.
Full text
8
Rönkä, S. (Sami). "Administration and management of software licenses in a heterogeneous environment:the case of global license service administration." Master's thesis, University of Oulu, 2013. http://urn.fi/URN:NBN:fi:oulu-201305201323.
Full textAbstract:
This work presents a solution developed for the case company to help in license service management and license usage tacking for both system administrators and license owners or end users. The thesis first covers the basics for licenses and different licensing models used in Research and Development environments. It continues with a study of available tools for license management and usage reporting and their suitability for large enterprises. Based on this and discussions with the case company a solution is derived for the case company. The developed solution consists of a toolset for end users of the license and for the administrators of the license services and servers. Processes to be used in the tool and in practice in the company are defined together with the future users of the solution. The processes are introduced in this thesis along with the implemented supporting functionality in the tool itself. The solution helps the end users and administrators with customer management, license service management and change management. It also provides simple methods for license usage statistics, which are developed to be easily upgradable or changeable by modular design. This in turn enables changing just the usage reporting part of the tool, when planning new functionalities to cover new requirements expected to come later due to large organizational changes in the company<br>Tämä työ esittelee ratkaisun, joka on kehitetty auttamaan esimerkkiyhtiötä lisenssipalveluiden hallinnassa ja lisenssien käyttöraportoinnissa. Ratkaisu on kehitetty palvelemaan sekä lisenssijärjestelmien ylläpitäjiä, että lisenssien organisationaalisia omistajia ja loppukäyttäjiä. Työssä käydään ensin läpi lisenssien perusteet ja erilaiset lisensointimallit, jotka ovat yleisimmin käytössä tutkimus- ja tuotekehitysyksiköissä. Sitten arvioidaan olemassa olevien lisenssinhallinta- ja käyttöraportointityökalujen soveltuvuutta suurille yhtiöille. Tämän ja esimerkkiyhtiön kanssa käytyjen keskusteluiden perusteella valittiin sopivin ratkaisu, joka myös toteutettiin osana ratkaisua. Tehty ratkaisu koostuu työkaluista loppukäyttäjille sekä lisenssipalveluiden ja palvelimien ylläpitäjille. Myös työkalussa sekä käytännön työssä käytettävät prosessit määritettiin yhdessä työkalun tulevien käyttäjien kanssa. Nämä prosessit esitellään työssä yhdessä niitä tukevien työkalujen toiminnallisuuksien kanssa. Kehitetty ratkaisu auttaa sekä loppukäyttäjiä että ylläpitäjiä asiakashallinnan, lisenssipalveluiden hallinnan ja muutoksenhallinnan avulla. Kehitetty järjestelmä tarjoaa yksinkertaiset työkalut lisenssipalveluiden käyttöraportointiin. Nämä työkalut sekä niiden rajapinnat ovat suunniteltu helposti vaihdettaviksi sekä päivitettäviksi modulaarisella suunnittelulla. Tämän ansiosta ainoastaan käyttöraportointi voidaan rakentaa paremmin tai kokonaan uusiksi tarvittaessa, kun suunnitellaan uusia ominaisuuksia tarjoamaan työkaluja uusille vaatimuksille, joita oletettavasti on tulossa myöhemmin johtuen suurista organisaatiomuutoksista esimerkkiyhtiössä
9
Ericsson, Joakim. "Object Migration in a Distributed, Heterogeneous SQL Database Network." Thesis, Linköpings universitet, Databas och informationsteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148181.
Full textAbstract:
There are many different database management systems (DBMSs) on the market today. They all have different strengths and weaknesses. What if all of these different DBMSs could be used together in a heterogeneous network? The purpose of this thesis is to explore ways of connecting the many different DBMSs together. This thesis will explore suitable architectures, features, and performance of such a network. This is all done in the context of Ericsson’s wireless communication network. This has not been done in this context before, and a big part of the thesis is exploring if it is even possible. The result of this thesis shows that it is not possible to find a solution that can fulfill the requirements of such a network in this context
10
Mies, Sebastian [Verfasser], and M. [Akademischer Betreuer] Zitterbart. "Autonomous Interconnection of Heterogeneous Networks / Sebastian Mies. Betreuer: M. Zitterbart." Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/1026283787/34.
Full text
11
Granlund, Daniel. "Secure and scalable roaming support in heterogeneous access networks." Licentiate thesis, Luleå tekniska universitet, Datavetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17883.
Full textAbstract:
Mobility support for users connecting to the Internet is an increasing trend. Different types of access networks like WiFi, CDMA, and UMTS are available, creating a heterogeneous access network environment. In the Internet today, there are a number of providers of various sizes supporting different technologies. Moving between such operators different types of authentication methods are often used interrupting ongoing services. This, in combination with lacking roaming agreements makes mobility among them with maintained connectivity and uninterrupted services difficult or even impossible.This thesis proposes an extended functionality to the Authentication, Authorization and Accounting, (AAA) protocol that enables a single AAA infrastructure to exist in a heterogeneous network environment and that enables interconnection between different operators in a tree-like structure of AAA servers. Mobile devices will maintain their IP address while connected to a network different from the home network independent of the network access technology. Furthermore, a scalability study is carried out in order to determine what is required from an AAA system in order for it to perform when dealing with larger numbers of users, service providers as well as supporting new technologies. A method for providing information for handover decisions for intra- and inter-operator mobility is also proposed. The proposed method selects the access network that according to a metric based on jitter and delay shows best performance.Evaluations show that authentication and IP address assignment can be supported in an efficient way in comparison with state of the art for both Ethernet and PPP based access networks using a common AAA infrastructure. CPU, memory and network link capacity in the home AAA server are identified as the primary bottlenecks when discussing scalability in RADIUS based AAA infrastructures and guidelines are proposed to address scalability issues during system design. The metric proposed to support in handover decisions shows that bandwidth can be estimated with more than 90% accuracy for WiFi, CDMA, and UMTS access networks.<br>Godkänd; 2011; 20110112 (dangra); LICENTIATSEMINARIUM Mobila system/Mobile Systems Examinator: Docent Christer Åhlund, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet Diskutant: Docent Mika Ylianttila, University of Oulu, Finland Tid: Fredag den 11 februari 2011 kl 10.00 Plats: Arenan, Institutionen för teknikvetenskap och matematik, Campus Skellefteå, Luleå tekniska universitet, Skellefteå
12
Luoto, M. (Markus). "Managing control information in autonomic wireless networking." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526216454.
Full textAbstract:
Abstract As mobile Internet access traffic continues to grow at an explosive rate and wireless networks continue to diverge into multiple access technologies with partly overlapping sets of features, new solutions for efficient use of these networks are vital. Cognitive network management provides tools to tackle this challenge by automatically learning from past experience the characteristics and usage patterns of the connected devices, thus enabling autonomic optimization of those connections. Cognitive network management requires a vast amount of information in order to function effectively, making collaboration of the networked devices essential as the best sources of information are scattered throughout the network. This makes efficient information dissemination one of the key enablers for autonomic networking. This dissertation studies managing control information related to autonomic selection of access networks and adapting services in a heterogeneous wireless network environment. It presents a solution to simple and efficient information dissemination in the form of Distributed Decision Engine— a CEP-like system enabling the building of a highly scalable and dynamic messaging system enabling dissemination, analysis and control of the complex series of interrelated events in the network. The dissertation also presents results showing a clear benefit in using cross-layer and cross-domain information in a modern wireless environment and validates the final prototype implementation of DDE with laboratory measurements. Effective use of disseminated cross-layer information is another key element in autonomic wireless networking. This dissertation also focuses on intelligent decision-making based on cross-layer information by presenting test results which attest that the performance of an autonomic wireless networking system can be improved by using cognitive techniques in its management algorithms, and that hierarchy and coordination can be utilized to minimize the effect of conflicting decisions of the system<br>Tiivistelmä Mobiilin Internet-liikenteen räjähdysmäinen kasvu ja langattomien verkkojen jatkuva jakautuminen useisiin tekniikoihin vaativat uusia ratkaisuja näiden verkkojen tehokkaaseen käyttöön. Kognitiivinen verkon hallinta mahdollistaa oppimisen, minkä avulla laitteiden yhteyksiä voidaan optimoida autonomisesti aiemman kokemuksen perusteella. Tällainen optimointi vaatii kuitenkin valtavan määrän verkosta ja laitteista kerättyä tietoa, mikä tekee tehokkaasta tiedonjakelusta keskeisen elementin autonomisessa verkon hallinnassa. Tässä väitöskirjassa tutkitaan verkon valintaan ja palveluiden sopeuttamiseen vaadittavan tiedon välittämistä ja hallintaa autonomisissa langattomissa verkoissa. Ratkaisuna yksinkertaiseen ja tehokkaaseen tiedonvälitykseen esitellään hajautettu Distributed Decision Engine -komponentti, joka mahdollistaa skaalautuvan tiedon jakelu-, analysointi- ja hallintajärjestelmän rakentamisen. Lisäksi väitöskirjassa kuvataan myös tuloksia, jotka osoittavat, että verkkokerrosten välisen tiedon käyttämisellä voidaan saavuttaa selvää etua, sekä tuloksia, jotka vahvistavat DDE-prototyyppitoteutuksen toimivuuden laboratoriomittauksin. Verkkokerrosten välisen tiedon tehokas hyödyntäminen on toinen keskeinen tekijä autonomisessa langattomien verkkojen hallinnassa. Väitöskirjassa käsitellään myös älykästä päätöksentekoa kyseisen informaation pohjalta sekä esitellään tuloksia, jotka osoittavat, että päätöksentekoa autonomisessa langattomien verkkojen hallinnassa voidaan parantaa kognitiivisilla tekniikoilla. Lisäksi esitetyt tulokset osoittavat, että hierarkialla sekä koordinoinnilla voidaan minimoida ristiriitaisten päätösten vaikutukset järjestelmään
13
Agnihotri, Mohit Kumar. "Energy efficient topology formation for Bluetooth mesh networks using heterogeneous devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187022.
Full textAbstract:
Internet of things (IoT) is the latest trend in our living spaces allowing machine to machine (M2M) communications at the extensive scale. To enable massive M2M communication and portable devices to run on limited power supplies for the extended duration of time, low-cost energy efficient wireless technologies are needed. Among the many competing technologies including Wi-Fi, Bluetooth has shown the potential to be one of the strong candidates to act as the connectivity solution for the IoT especially after the introduction of Bluetooth Low Energy (BLE). Nowadays BLE is one of the biggest players in the market of short-range wireless technologies. By 2020, nearly 30 billion BLE devices in the form of mobile phones, tablets, sports utilities, sensors, security systems and health monitors are expected to be shipped. This proliferation of low-cost devices may for the first time actualize the vision of IoT. This thesis studies various mesh topology formation techniques that can be used to aid the development of large-scale networks in capillary networks focusing on BLE. In particular, the thesis focuses on how mesh networks can be established over BLE communications especially exploiting the heterogeneous characteristics of the devices. A novel algorithm is proposed called Topology Formation considering Role Suitability (TFRS) to maximize the network lifetime. The algorithm uses a newly introduced metric called role suitability metric (RSM) to assign the best role among master, relay and slave to a device. The RSM metric bases its decision on various device characteristics including, but not limited to, energy, mobility, and computational capability. We use the system-level simulation to evaluate the performance of the proposed algorithm against a reference under homogeneous deployment scenario consisting of heterogeneous devices. Results show that the network lifetime can be improved significantly when the topology is formed considering the device characteristics for both master role selection and relay selection. TFRS can achieve moderate improvements ranging from 20% to 40% varying on the deployment characteristics over the reference case.
14
Bossardt, Matthias [Verfasser]. "Composition and Deployment of Services in Heterogeneous Programmable Networks / Matthias Bossardt." Aachen : Shaker, 2006. http://d-nb.info/1170533604/34.
Full text
15
Botterman, Hông-Lan. "Corrélations dans les graphes d'information hétérogène : prédiction et modélisation de liens à partir de méta-chemins." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS083.
Full textAbstract:
De nombreuses entités possiblement de natures différentes sont reliées par des liens pouvant également être de natures différentes. De telles données peuvent être représentées par un graphe d’information hétérogène (heterogeneous information network, HIN). De plus, il existe souvent des corrélations entre entités ou événements de la vie réelle. Une fois ces derniers représentés par des abstractions appropriées telles que les HIN, les corrélations peuvent dès lors se retrouver dans ces graphes particuliers. Motivé par ces considérations, cette thèse s’intéresse aux effets des possibles corrélations entre les liens d’un HIN sur sa structure. Ce présent travail tente de répondre à des questions telles que : y a-t-il des corrélations entre les liens de différents types ? Si oui, est-il possible de les quantifier ? Que signifient-elles ? Est-ce que ces corrélations peuvent servir à prédire l’apparition de liens ? À modéliser des dynamiques de co-évolution ? Les exemples étudiés peuvent être divisés en deux catégories. Premièrement, l’utilisation des corrélations pour la prédiction du poids des liens est étudiée. Il est montré que les corrélations entre les liens, et plus particulièrement entre les chemins, peuvent être utilisées pour récupérer et prédire le poids d’autres liens, d’un type spécifié. Deuxièmement, une dynamique de poids de liens est considérée. Il est montré que la co-évolution de liens peut servir, par exemple, à définir un modèle d’attention entre individus et sujets. Les résultats préliminaires sont en accord avec d’autres présents dans la littérature, principalement relatifs aux modèles de dynamiques d’opinions. Globalement, ce travail illustre l’importance des corrélations entre les liens d’un HIN. En outre, il soutient le fait général que différents types de nœuds et liens abondent dans la nature et qu’il peut être important et instructif de prendre en compte cette diversité afin de comprendre l’organisation et le fonctionnement d’un système<br>Many entities, possibly of different natures, are linked by physical or virtual links, that may also be of different natures. Such data can be represented by a heterogeneous information network (HIN). In addition, there are often correlations between real-life entities or events. Once represented by suitable abstractions (such as HIN), these correlations can therefore be found in the HIN. Motivated by these considerations, this thesis investigates the effects of possible correlations between the links of an HIN on its structure. This present work aims at answering questions such as: are there indeed correlations between different types of links? If so, is it possible to quantify them? What do they mean? How can they be interpreted? Can these correlations be used to predict the occurrence of links? To model co-evolution dynamics? The examples studied can be divided into two categories. First, the use of correlations for the prediction of the links’ weight is studied. It is shown that correlations between links, and more specifically between paths, can be used to recover and, to some extent, predict the weight of other links of a specified type. Second, a link weight dynamics is considered. It is shown that link co-evolution can be used, for example, to define a model of attention between individuals and subjects. The preliminary results are in agreement with others in the literature, mainly related to models of opinion dynamics. Overall, this work illustrates the importance of correlations between the links of an HIN. In addition, it supports the general fact that different types of nodes and links abound in nature and that it could be important and instructive to take this diversity into account in order to understand the organization and functioning of a system
16
Ternon, Emmanuel [Verfasser]. "Energy Savings in Phantom Cell Concept Heterogeneous Networks / Emmanuel Ternon." Aachen : Shaker, 2017. http://d-nb.info/1124366598/34.
Full text
17
Piri, E. (Esa). "Improving heterogeneous wireless networking with cross-layer information services." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526208213.
Full textAbstract:
Abstract Substantially growing data traffic over wireless networks poses increased challenges for mobile network operators in deploying sufficient network resources and managing user mobility. This dissertation considers these challenges to providing satisfactory Quality of Service (QoS) for end-users and studies solutions for better utilization of the heterogeneous network environment. First, the dissertation examines what solutions mobile devices and network management entities can use to dynamically collect valid cross-layer information from different network entities. Cross-layer information allows monitoring of the condition of the network in multiple layers on a user and application basis. The second research topic considers the techniques the network management entities can use to improve resource usage in wireless networks based on the collected cross-layer information. The IEEE 802.21 standard, specified to facilitate handovers between heterogeneous networks, is used as the basis for cross-layer information delivery. This dissertation also focuses on utilization of the standard beyond the inter-access technology handovers. In order to improve resource usage in wireless networks dynamically, event delivery enhancements are proposed for the standard so that it better applies to the requirements of different techniques. Such techniques are traffic priority adjustment, traffic adaptation, packet aggregation, and network protocol header compression. The results show that when a handover is not feasible, these techniques effectively allow sharing of the limited radio resources for the user data according to applications’ importance and type. Mobility management is studied in terms of network information service, one of the main services of IEEE 802.21. The thesis proposes enhancing the information service with a base station cell coverage area database. The database provides significant improvements for the selection of a handover target in a dense base station environment. With all the results taken together, the dissertation provides mobile network operators various means to improve the usage of wireless networks on the basis of applications’ varying QoS requirements<br>Tiivistelmä Voimakkaasti kasvava langattomien tietoverkkojen dataliikenne aiheuttaa verkko-operaattoreille haasteita tarjota riittävät verkkoresurssit ja hallita käyttäjien liikkuvuutta. Väitöskirja huomioi nämä haasteet tarjota loppukäyttäjille tyydyttävä palvelunlaatu (QoS) ja tutkii ratkaisuja, joilla heterogeenistä verkkoympäristöä voidaan hyödyntää tehokkaammin. Aluksi väitöskirja tutkii, mitä ratkaisuja päätelaitteet ja verkkohallintatoimijat voivat käyttää keräämään protokollakerrosten välistä (cross-layer) tietoa eri verkkotoimijoilta. Protokollakerrosten välinen tieto mahdollistaa verkon tilan seuraamisen usealla eri kerroksella käyttäjä- ja sovelluskohtaisesti. Toinen tutkimusaihe tarkastelee protokollakerrosten välistä tietoa hyödyntäviä tekniikoita, joita verkonhallintatoimijat voivat käyttää tehostamaan resurssien käyttöä langattomissa verkoissa. IEEE 802.21-standardia, joka on määritetty helpottamaan verkonvaihtoja heterogeenisten verkkojen välillä, käytetään pohjana protokollakerrosten välisen tiedon jakelulle. Väitöskirjassa keskitytään standardin hyödyntämiseen myös muussa kuin verkkoteknologioiden välisen verkonvaihdon yhteydessä. Väitöskirja ehdottaa parannuksia standardin tapahtumatietovälitykseen, jotta se täyttäisi paremmin eri tekniikoiden asettamat vaatimukset dynaamisesti toteutettavista toimista langattomien verkkojen resurssikäytön tehostamiseksi. Nämä tekniikat ovat liikenteen prioriteetin muutokset, liikenteen adaptointi, pakettien yhdistäminen ja verkkoprotokollaotsikoiden pakkaus. Tulokset osoittavat, että kun tukiasema- tai verkonvaihto ei ole mahdollinen, nämä tekniikat mahdollistavat rajattujen verkkoresurssien jakamisen tehokkaasti sovellusten tärkeyden ja tyypin mukaan. Liikkuvuudenhallintaa tutkitaan verkkoinformaatiopalvelun, joka on myös yksi IEEE 802.21-standardin pääpalveluista, kautta. Väitöskirja ehdottaa, että informaatiopalvelua tehostetaan liittämällä siihen tietokanta tukiasemasolujen peittoalueista. Tietokanta tehostaa huomattavasti verkonvaihdon kohteen valintaa tiheissä tukiasemaympäristöissä. Kun väitöskirjan tulokset huomioidaan kokonaisuutena, väitöskirja tarjoaa verkko-operaattoreille useita tapoja tehostaa langattomien verkkojen käyttöä sovellusten vaihtelevien palvelunlaatuvaatimusten perusteella
18
Turner, Eric G. "Solution analysis of universal wireless joint point technologies for heterogeneous tactical networks." Thesis, Monterey, California. Naval Postgraduate School, 2006. http://hdl.handle.net/10945/2951.
Full textAbstract:
The scope of this thesis is to analyze the feasibility of having different wireless mesh network architectures transfer data to a wired network via a joint (universal) access point (UAP). Additionally this thesis analyzes the feasibility of using similar joint (universal) access point technology to allow heterogeneous wireless mesh network devices in close proximally to the UAP transmit data to/from each other via the UAP. This research also includes evaluating COTS tools for possible implementation of a joint access point as well as seeking partnership with private industry to assist in research efforts and/or the development or joint (universal) access point solution(s). The thesis concludes with a recommendation on application of universal joint point technology, to include recommendations for implementation of such technology in the Tactical Network Topology (TNT) environment.
19
Özyagci, Ali. "Selfish Dynamic Spectrum Access in Multichannel Wireless Networks : Complete and incomplete information analysis." Licentiate thesis, KTH, Kommunikationssystem, CoS, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-50738.
Full textAbstract:
The increasing popularity and widespread deployment of wireless data systems fuel the increasing demand for more spectrum. On the other hand, various studies measuring spectrum utilization show that there is a huge variation in spectrum utilization at different times and locations. In view of this, various dynamic spectrum access (DSA) methods have been proposed in order to achieve more efficient utilization of spectrum resources by virtue of exploiting the variations in spectrum demand over time and space. Implementing DSA systems in a centralized way can lead to complexity and scalability problems due to the extensive control signaling involved. Therefore distributed implementations of DSA systems in which the users can access the system resources at their own discretion have been proposed. These distributed mechanisms typically incorporate cognitive radio systems which act as agents on behalf of users to measure the radio environment and make decisions based on these measurements. On the other hand, the freedom of the users in distributed systems to form their actions can lead each user to try to maximize its benefit from the system without regard the overall performance of the DSA system. Therefore, selfish behavior can prevail in distributed systems, which is likely to degrade the system performance.In this thesis we investigate the implications of selfish decision making in dynamic spectrum access systems. To address this broad problem, we focus our analysis on a particular system which can represent the essential properties of DSA systems and thus can shed light on the performance of the broad class of DSA systems with selfish users. Specifically, we model a DSA system as a multichannel random access system which uses ALOHA for medium access, and we analyze the behavior of the selfish users by modeling the system as a non-cooperative game. In this analysis we incorporate the effect of channel state information on the decision making of the users; we consider both cases when the users act on global (complete) and on local (incomplete) information. We determine the behavior of the selfish users at the Nash equilibria of the non-cooperative game and measure the performance of the system in terms of sum and individual utilities for various user loads and amount of available resources. We try to identify how the performance of the DSA system with selfish users compares with its cooperative counterpart. By performing these analyses we provide insights into the broader question of whether selfish users can utilize spectrum resources in a DSA system as well as cooperative users.<br><p>QC 20111208</p><br>MultiOperator Dynamic Spectrum access (MODyS)
20
Hahn, Sören [Verfasser]. "Mobile Radio Network Management in the Context of Realistic Heterogeneous Scenarios / Sören Hahn." Aachen : Shaker, 2017. http://d-nb.info/1149272163/34.
Full text
21
Buburuzan, Teodor [Verfasser]. "Optimization of an Interface Abstraction Layer for Heterogeneous Networks / Teodor Buburuzan." Aachen : Shaker, 2011. http://d-nb.info/1071528947/34.
Full text
22
Karlsson, Linda Sofia. "Coding for Improved Perceived Quality of 2D and 3D Video over Heterogeneous Networks." Doctoral thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11461.
Full textAbstract:
The rapid development of video applications for TV, the internet and mobile phones is being taken one step further in 2010 with the introduction of stereo 3D TV. The 3D experience can be further improved using multiple views in the visualization. The transmission of 2D and 3D video at a sufficiently perceived quality is a challenge considering the diversity in content, the resources of the network and the end-users.Two problems are addressed in this thesis. Firstly, how to improve the perceived quality for an application with a limited bit rate. Secondly, how to ensure the best perceived quality for all end-users in a heterogeneous network. A solution to the first problem is region-of-interest (ROI) video coding, which adapts the coding to provide a better quality in regions of interest to the viewer. A spatio-temporal filter is proposed to provide codec and standard independent ROI video coding. The filter reduces the number of bits necessary to encode the background and successfully re-allocate these bits to the ROI. The temporal part of the filter reduces the complexity compared to only using a spatial filter. Adaption to the requirements of the transmission channel is possible by controlling the standard deviation of the filter. The filter has also been successfully applied to 3D video in the form of 2D-plus-depth, where the depth data was used in the detection of the ROI. The second problem can be solved by providing a video sequence that has the best overall quality. Hence, the best quality for each part of the network and for each 2D and 3D visualization system over time. Scalable video coding enables the extraction of the parts of the data to adapt to the requirements of the network and the end-user. A scheme is proposed in this thesis that provides scalability in the depth and view domain of multi-view plus depth video. The data are divided into enhancement layers depending on the content’s distance to the camera. Schemes to divide the data into layers within a view and between adjacent views have been analyzed. The quality evaluation indicates that the position of the layers in depth as well as the number of layers should be determined by analyzing the depth distribution. The front-most layers in adjacent views should be given priority over the others unless the application requires a high quality of the center views.<br>Den snabba utvecklingen av videoapplikation för TV, Internet och mobiltelefoner tar ytterliggare ett steg i och med introduceringen av stereo 3D TV under 2010. Upplevelsen av 3D kan förstärkas ytterliggare genom att använda multipla vyer i visualiseringen. Skillnaden i innehåll, nätverksresurser och slutanvändare gör överföring av 2D och 3D video med en tillräcklig hög upplevd kvalitet till en utmaning. För det första, hur man ökar den upplevda kvalitén hos en applikation med en begränsad överföringshastighet. För det andra, hur man tillhandahåller den bästa upplevda kvalitén hos alla slutanvändare i ett heterogent nätverk. Region-of-interest (ROI) videokodning är en lösning till det första problemet, vilken anpassar kodningen för att ge högre kvalitet i regioner som är intressanta för användaren. Ett spatio-temporalt filter är föreslaget för att tillhandahålla codec- och standardoberoende ROI videokodning. Filtret reducerar antalet bitar som krävs för att koda bakgrunden och omfördelar dessa till ROI:t. Den temporala delen av filtret minskar komplexiteten jämfört med att använda enbart spatiala filter. Filtret kan anpassas till överföringshastigheten genom att ändra standardavvikelsen för filtret. Filtret har också˙ använts på˙ 3D video i formen 2D-plus-depth, där djupdata användes i ROI detektionen. Det andra problemet kan lösas genom att tillhandahålla en videosekvens som har högsta möjliga kvalitet i hela nätverket. Därmed även den bästa kvaliteten för for varje del av nätverket och för varje 2D- och 3D-skärm. Skalbar videokodning gör det möjligt att extrahera delar av datan för anpassning till de rådande förutsättningarna. En metod som ger skalbarhet i djupet och mellan kameravyer hos multi-view plus depth video har föreslagits. Videosekvensen delas upp i lager beroende på innehållets avstånd till kameran. Metoder för att fördela data över lager i djupet och mellan närliggande vyer har analyserats. Kvalitetsutvärderingen visar att lagrens position i djupet och antalet lager bör bestämmas utifrån fördelningen av djupdata. De främsta lagren i närliggande vyer bör ges högre prioritet om inte applikationen kräver hög kvalitet hos vyer i centrum.<br>Medi3D<br>3D-reklam<br>MediaSense
23
Richards, Clyde E. Jr. "Intelligent-Agent-Based Management of Heterogeneous Networks for the Army Enterprise." Thesis, Monterey, California. Naval Postgraduate School, 2003. http://hdl.handle.net/10945/879.
Full textAbstract:
Approved for public release; distribution in unlimited.<br>The Army is undergoing a major realignment in accordance with the Joint Vision 2010/2020 transformation to establish an enterprise command that is the single authority to operate and manage the Army Enterprise Information Infrastructure (Infrastructure). However, there are a number of critical network management issues that the Army will have to overcome before attaining the full capabilities to manage the full spectrum of Army networks at the enterprise level. The Army network environment consists of an excessive number of heterogeneous applications, systems, and network architectures that are incompatible. There are a number of legacy systems and proprietary platforms. Most of the NM architectures in the Army are based on traditional centralized NM approaches such as the Simple Network Management Protocol (SNMP). Although SNMP is the most pervasive protocol, it lacks the scalability, reliability, flexibility and adaptability necessary to effectively support an enterprise network as large and complex as the Army. Attempting to scale these technologies to this magnitude can be extremely difficult and very costly. This thesis makes the argument that intelligent-agent-based technologies are a leading solution, among the other current technologies, to achieve the Army's enterprise network management goals.<br>Major, United States Army
24
Kaleva, J. (Jarkko). "Decentralized multiantenna transceiver optimization for heterogeneous networks." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526219653.
Full textAbstract:
Abstract This thesis focuses on transceiver optimization for heterogeneous multi-user multiple-input multiple-output (MIMO) wireless communications systems. The aim is to design decentralized beamforming methods with low signaling overhead for improved spatial spectrum utilization. A wide range of transceiver optimization techniques are covered, with particular consideration of decentralized optimization, fast convergence, computational complexity and signaling limitations. The proposed methods are shown to provide improved rate of convergence, when compared to the conventional weighted minimum MSE (WMMSE) approach. This makes them suitable for time-correlated channel conditions, in which the ability to follow the changing channel conditions is essential. Coordinated beamforming under quality of service (QoS) constraints is considered for interfering broadcast channel. Decomposition based decentralized processing approaches are shown to enable the weighted sum rate maximization (WSRMax) in time-correlated channel conditions. Pilot-aided decentralized WSRMax beamformer estimation is studied for coordinated multi-point (CoMP) joint processing (JP). In stream specific estimation (SSE), all effective channels are individually estimated. The beamformers are then constructed from the locally estimated channels. On the other hand, with direct estimation (DE) of the beamformers, only the intended signal needs to be separately estimated and the covariance matrices are implicitly estimated from the received pilot training matrices. This makes the pilot design more robust to pilot contamination. These methods show that CoMP JP is feasible even in relatively fading channel conditions and with limited backhaul capacity by employing decentralized beamformer processing. In the final part of the thesis, a relay-assisted cellular system with decentralized processing is considered, in which users are served either directly by the base stations or via relays for WSRMax or sum power minimization subject to rate constraints. Zero-forcing and coordinated beamforming provide a trade-off between complexity, in-band signaling and spectrum utilization. Relays are shown to be beneficial in many scenarios when the in-band signaling is accounted for. This thesis shows that decentralized downlink MIMO transceiver design with a reasonable computational complexity is feasible in various system architectures even when signaling resources are limited and channel conditions are moderately fast fading<br>Tiivistelmä Tämä väitöskirja keskittyy lähetin- ja vastaanotinoptimointiin heterogeenisissä monikäyttäjä- ja moniantennijärjestelmissä. Tavoitteena on parantaa tilatason suorituskykyä tutkimalla hajautettuja keilanmuodostusmenetelmiä, joissa ohjaussignaloinnin tarve on alhainen. Erityisesti keskitytään hajautetun keilanmuodostuksen optimointiin, nopeaan konvergenssiin, laskennalliseen kompleksisuuteen sekä signaloinnin rajoitteisiin. Esitettyjen menetelmien osoitetaan parantavan konvergenssinopeutta ja vähentävän signaloinnin tarvetta, verrattaessa tunnettuun WMMSE-menetelmään. Nämä mahdollistavat lähetyksen aikajatkuvissa kanavissa, joissa kanavan muutosten seuraaminen on erityisen tärkeää. Näiden menetelmien osoitetaan mahdollistavan hajautetun ja priorisoidun tiedonsiirtonopeuden maksimoinnin monisolujärjestelmissä sekä aikajatkuvissa kanavissa käyttäjäkohtaisilla siirtonopeustakuilla. Pilottiavusteisten lähetys- ja vastaanotinkeilojen estimointia tutkitaan yhteislähetysjärjestelmissä. Yksittäisten lähetyskanavien estimoinnissa effektiiviset kanavat estimoidaan yksitellen, ja lähetys- ja vastaanotinkovarianssimatriisit muodostetaan summaamalla paikalliset kanavaestimaatit. Suoraestimoinnissa ainoastaan oman käyttäjän effektiivinen kanava estimoimaan erikseen. Tällöin kovarianssimatriisit saadaan suoraan vastaanotetuista pilottisignaaleista. Tämä tekee estimaateista vähemmän herkkiä häiriölle. Hajautetun yhteislähetyksen osoitetaan olevan mahdollista, jopa verrattain nopeasti muuttuvissa kanavissa sekä rajallisella verkkoyhteydellä lähettimien välillä. Viimeisessä osassa tutkitaan välittäjä-avusteisia järjestelmiä, joissa käyttäjiä palvellaan joko suoraan tukiasemasta tai välittäjä-aseman kautta. Optimointikriteereinä käytetään siirtonopeuden maksimointia sekä lähetystehon minimointia siirtonopeustakuilla. Nollaanpakottava sekä koordinoitu keilanmuodostus tarjoavat valinna laskennallisen kompleksisuuden, ohjaussignaloinnin sekä suorituskyvyn välillä. Välittäjä-avusteisen lähetyksen osoitetaan olevan hyödyllisiä useissa tilanteissa, kun radiorajanpinnan yli tapahtuvan signaloinnin tarve otetaan huomioon keilanmuodostuksessa. Tässä väitöskirjassa osoitetaan hajautetun keilanmuodostuksen olevan mahdollista verrattaen vähäisillä laskennallisilla resursseilla heterogeenisissä moniantennijärjestelmissä. Esitetyt menetelmät tarjoavat ratkaisuja järjestelmiin, joissa ohjaussignalointiresurssit ovat rajallisia ja radiokanava on jatkuvasti muuttuva
25
Mertz, Frank [Verfasser]. "Efficient audio communication over heterogeneous packet networks with wireless access / Frank Mertz." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1018219447/34.
Full text
26
Mugga, Charles, and Dong Sun. "Performance comparison of multihoming and mobility protocols in IPv6 heterogeneous network environment." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2800.
Full textAbstract:
Multihoming and mobility protocols enable computing devices to stay always best connected (ABC) to the Internet in the heterogeneous wireless environment. The ABC concept affords users the ability to choose the best available access networks and devices that best suit their needs, at any given point in time. With the emergence of multi-interfaced terminals, a mobile node may connect to different access networks simultaneously through multiple interfaces. This is called multihoming, and it allows a user to enjoy the best access for each application as well as other benefits such as fault tolerance, ubiquitous access and load balancing. Also, while the mobile node is moving from one wireless network to another, mobility management is important in keeping the node’s communication active during handover events. Therefore, the heterogeneous wireless environment requires the associated management of both multihoming and mobility since the mobile hosts are mobile and multihomed at the same time. Consequently, the purpose of our research is to compare the prevailing multihoming and mobility management protocols and corresponding implementations in the IPv6 heterogeneous wireless environment, and to identify the suitable protocol framework that supports both multihoming and mobility. The research started out with the study of the prominent host-based multihoming and mobility management protocols and solutions in IPv6. It then proceeded with a comparative qualitative review of the identified multihoming and mobility protocols according to their mechanisms, modes of operation, benefits and drawbacks. From the qualitative review, we identified suitable protocols that showed better performance for management of mobility and/or multihoming. Moreover, this provided a basis for defining the relevant simulation metrics for our comparative quantitative simulation analysis. The quantitative analysis was carried out using simulations on the OMNeT++ software platform, with the objective of comparing the performance of the studied multihoming and mobility protocols. Simulation scenarios were designed for mobility and multihoming cases, implemented and run using pertinent simulation protocol models of OMNeT++. The performance evaluation was investigated in terms of handover latency and rehoming time for mobility and multihoming protocols respectively. The simulation survey focused on the following protocols:Mobile IPv6 (MIPv6), Multiple Care-of Address (MCoA), Host Identity Protocol (HIP) and Stream Control Transmission Protocol (SCTP). Both the qualitative analysis and the results from the simulation study have shown that HIP has the best performance for mobility and multihoming management. Accordingly, our research has identified HIP as the best suitable framework that supports both multihoming and mobility management in IPv6 heterogeneous network environment. In addition, this project has demonstrated that multihomed nodes with multiple addresses experience less impact on real-time communication in case network failures or mobile movements compared to single-homed nodes.<br>Charles Mugga: +256790506653, Dong Sun: +8615106959570
27
Gebregergis, Tukue Gebremariam. "Energy saving using traffic adaptive base station operation (cell DTX) in heterogeneous cellular networks." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186397.
Full textAbstract:
Nowadays, mobile broadband data traffic is growing exponentially and will continue to grow for the coming years. Accordingly, the operational cost of a mobile network will increase significantly due to the fact that a large number of base stations will be deployed to support the high traffic demand. Besides, the increase of the power consumption of a mobile network has a negative impact on the environment because of increased carbon footprint. As a result, energy efficiency in cellular networks has gained a great interest in the research community. Hence, several approaches have been investigated to lower the mismatch between base station operations and temporal and spatial characteristic of the traffic demand in a network. For example, cell discontinuous transmission which deactivates some portion of the BS during the unused transmission time interval (TTI) is one of the techniques proposed to reduce power consumption in LTE networks. This thesis work investigates potential energy savings due to the deployment of low power BSs that have cell DTX capability in a cellular mobile radio network in both urban and dense urban area deployments. A time static system level simulation has been used in a downlink communication in order to evaluate and demonstrate the energy savings. Besides, the European long term large scale traffic model has been implemented to make the system level simulation more realistic. Areapower consumption is used as the main performance metric to evaluate the energy saving in the deployment options and traffic adaptive energy efficiency features considered. Results show that, the power saving of a hetrogenous network increases as a result of the enhancement of the BSs’ hardware to put itself in to sleep mode and by deploying an optimum number of low power BS at the cell border of the macro BS considering hotspots. However, the energy efficiency techniques that can be implemented to give maximum power saving highly depends on the traffic demand of the deployment area. Hence, there is no benefit of deploying small cells if the demand is low and if there is no significant traffic load to offload from the macro layer. In this work, using the traffic model mentioned above and time static system level simulation, it is found that an optimal number of small cells per macro gives the minimum area power consumption when the BS is capable of switching off 90% of its components during idle mode in a dense urban area deployment. This deployment scenario has around 36% power saving during the peak hour and 12.5 % daily average power saving compared to a macro only network with cell DTX capability. On the other hand, under urban area traffic scenario, heterogeneous deployment for the same cell DTX factor does not bring any area power consumption reduction.
28
Martínez, Anny. "An ontology-based approach toward the configuration of heterogeneous network devices." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/299803.
Full textAbstract:
Despite the numerous efforts of standardization, semantic issues remain in effect in many subfields of networking. The inability to exchange data unambiguously between information systems and human resources is an issue that hinders technology implementation, semantic interoperability, service deployment, network management, technology migration, among many others. In this thesis, we will approach the semantic issues in two critical subfields of networking, namely, network configuration management and network addressing architectures. The fact that makes the study in these areas rather appealing is that in both scenarios semantic issues have been around from the very early days of networking. However, as networks continue to grow in size and complexity current practices are becoming neither scalable nor practical.
One of the most complex and essential tasks in network management is the configuration of network devices. The lack of comprehensive and standard means for modifying and controlling the configuration of network elements has led to the continuous and extended use of proprietary Command Line Interfaces (CLIs). Unfortunately, CLIs are generally both, device and vendor-specific. In the context of heterogeneous network infrastructures---i.e., networks typically composed of multiple devices from different vendors---the use of several CLIs raises serious Operation, Administration and Management (OAM) issues. Accordingly, network administrators are forced to gain specialized expertise and to continuously keep knowledge and skills up to date as new features, system upgrades or technologies appear. Overall, the utilization of proprietary mechanisms allows neither sharing knowledge consistently between vendors' domains nor reusing configurations to achieve full automation of network configuration tasks---which are typically required in autonomic management. Due to this heterogeneity, CLIs typically provide a help feature which is in turn an useful source of knowledge to enable semantic interpretation of a vendor's configuration space. The large amount of information a network administrator must learn and manage makes Information Extraction (IE) and other forms of natural language analysis of the Artificial Intelligence (AI) field key enablers for the network device configuration space. This thesis presents the design and implementation specification of the first Ontology-Based Information Extraction (OBIE) System from the CLI of network devices for the automation and abstraction of device configurations. Moreover, the so-called semantic overload of IP addresses---wherein addresses are both identifiers and locators of a node at the same time---is one of the main constraints over mobility of network hosts, multi-homing and scalability of the routing system. In light of this, numerous approaches have emerged in an effort to decouple the semantics of the network addressing scheme. In this thesis, we approach this issue from two perspectives, namely, a non-disruptive (i.e., evolutionary) solution to the current Internet and a clean-slate approach for Future Internet. In the first scenario, we analyze the Locator/Identifier Separation Protocol (LISP) as it is currently one of the strongest solutions to the semantic overload issue. However, its adoption is hindered by existing problems in the proposed mapping systems. Herein, we propose the LISP Redundancy Protocol (LRP) aimed to complement the LISP framework and strengthen feasibility of deployment, while at the same time, minimize mapping table size, latency time and maximize reachability in the network. In the second scenario, we explore TARIFA a Next Generation Internet architecture and introduce a novel service-centric addressing scheme which aims to overcome the issues related to routing and semantic overload of IP addresses.<br>A pesar de los numerosos esfuerzos de estandarización, los problemas de semántica continúan en efecto en muchas subáreas de networking. La inabilidad de intercambiar data sin ambiguedad entre sistemas es un problema que limita la interoperabilidad semántica. En esta tesis, abordamos los problemas de semántica en dos áreas: (i) la gestión de configuración y (ii) arquitecturas de direccionamiento. El hecho que hace el estudio en estas áreas de interés, es que los problemas de semántica datan desde los inicios del Internet. Sin embargo, mientras las redes continúan creciendo en tamaño y complejidad, los mecanismos desplegados dejan de ser escalabales y prácticos. Una de las tareas más complejas y esenciales en la gestión de redes es la configuración de equipos. La falta de mecanismos estándar para la modificación y control de la configuración de equipos ha llevado al uso continuado y extendido de interfaces por líneas de comando (CLI). Desafortunadamente, las CLIs son generalmente, específicos por fabricante y dispositivo. En el contexto de redes heterogéneas--es decir, redes típicamente compuestas por múltiples dispositivos de distintos fabricantes--el uso de varias CLIs trae consigo serios problemas de operación, administración y gestión. En consecuencia, los administradores de red se ven forzados a adquirir experiencia en el manejo específico de múltiples tecnologías y además, a mantenerse continuamente actualizados en la medida en que nuevas funcionalidades o tecnologías emergen, o bien con actualizaciones de sistemas operativos. En general, la utilización de mecanismos propietarios no permite compartir conocimientos de forma consistente a lo largo de plataformas heterogéneas, ni reutilizar configuraciones con el objetivo de alcanzar la completa automatización de tareas de configuración--que son típicamente requeridas en el área de gestión autonómica. Debido a esta heterogeneidad, las CLIs suelen proporcionar una función de ayuda que fundamentalmente aporta información para la interpretación semántica del entorno de configuración de un fabricante. La gran cantidad de información que un administrador debe aprender y manejar, hace de la extracción de información y otras formas de análisis de lenguaje natural del campo de Inteligencia Artificial, potenciales herramientas para la configuración de equipos en entornos heterogéneos. Esta tesis presenta el diseño y especificaciones de implementación del primer sistema de extracción de información basada en ontologías desde el CLI de dispositivos de red, para la automatización y abstracción de configuraciones. Por otra parte, la denominada sobrecarga semántica de direcciones IP--en donde, las direcciones son identificadores y localizadores al mismo tiempo--es una de las principales limitaciones sobre mobilidad, multi-homing y escalabilidad del sistema de enrutamiento. Por esta razón, numerosas propuestas han emergido en un esfuerzo por desacoplar la semántica del esquema de direccionamiento de las redes actuales. En esta tesis, abordamos este problema desde dos perspectivas, la primera de ellas una aproximación no-disruptiva (es decir, evolucionaria) al problema del Internet actual y la segunda, una nueva propuesta en torno a futuras arquitecturas del Internet. En el primer escenario, analizamos el protocolo LISP (del inglés, Locator/Identifier Separation Protocol) ya que es en efecto, una de las soluciones con mayor potencial para la resolucion del problema de semántica. Sin embargo, su adopción está limitada por problemas en los sistemas de mapeo propuestos. En esta tesis, proponemos LRP (del inglés, LISP Redundancy Protocol) un protocolo destinado a complementar LISP e incrementar la factibilidad de despliegue, a la vez que, reduce el tamaño de las tablas de mapeo, tiempo de latencia y maximiza accesibilidad. En el segundo escenario, exploramos TARIFA una arquitectura de red de nueva generación e introducimos un novedoso esquema de direccionamiento orientado a servicios.
29
Ojanperä, T. (Tiia). "Cross-layer optimized video streaming in heterogeneous wireless networks." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526201511.
Full textAbstract:
Abstract This dissertation studies the impact of heterogeneous wireless networks on the design and implementation of mobile video streaming services. The aim is to enable Quality of Service (QoS) sensitive video streaming services to take full advantage of the access diversity of heterogeneous networks in order to optimize their operation in terms of quality and efficiency of network resource usage. This nevertheless requires support beyond the layered communication architecture of today’s Internet. The thesis proposes an architecture for end-to-end cross-layer signaling and control for video streaming systems. The architecture supports extensive context informa- tion transfer in heterogeneous networks; thus, enabling the efficient management of video stream adaptation and user terminal mobility in a diverse and dynamic network environment. This thesis also studies and proposes cross-layer enhancements for adaptive video streaming and mobility management functions enabled by the cross- layer architecture. These include cross-layer video adaptation, congestion-triggered handovers, and concurrent utilization of multiple access networks in the video stream transport. For the video adaptation and multipath transmission, the flexible adaptation and transmission capabilities of the novel scalable video coding technology are used. Regarding the mobility management, the proposed solutions essentially enhance the handover decision-making of the Mobile IP protocol to better support QoS-sensitive video streaming. Finally, the thesis takes a holistic view on the application adaptation and mobility management, and proposes a solution for coordinated control of these two operations in order to achieve end-to-end optimization. The resulting mobile video streaming system architecture and the cross-layer control algorithms are evaluated using network simulations and real prototypes. Based on the results, the proposed mechanisms can be seen to be viable solutions for improving video streaming performance in heterogeneous wireless networks. They require changes in the communication end-points and the access network but support gradual deployment. This allows service providers and operators to select only a subset of the proposed mechanisms for implementation. The results also support the need for cross-layer signaling and control in facilitating efficient management and utilization of heterogeneous wireless networks<br>Tiivistelmä Väitöskirja tutkii langattomien ja heterogeenisen verkkoympäristöjen vaikutusta erityisesti mobiilikäyttöön suunnattuihin suoratoistovideopalveluihin (streaming). Työn tavoitteena on löytää keino optimoida verkkoyhteyden palvelunlaadulle (QoS) herkän suoratoistovideon toiminta sekä videopalvelun laadun että verkon tiedonsiirtokapasiteetin käytön osalta. Tämä tapahtuu mahdollistamalla heterogeenisten verkkojen tehokas käyttö suoratoistovideopalvelujen tapauksessa. Tavoitellut parannukset vaativat kuitenkin muutoksia nykyiseen kerroksittaiseen Internet-arkkitehtuuriin. Väitöskirjassa esitetään arkkitehtuuri protokollakerrosten välisen tiedon (cross-layer) välitykseen ja hyödyntämiseen suoratoistovideopalvelujen tiedonsiirron kontrolloinnissa. Arkkitehtuuria voidaan käyttää laaja-alaiseen kontekstitiedon välitykseen tietoverkoissa, mikä mahdollistaa tehokkaan videopalvelun adaptoinnin ja päätelaitteen liikkuvuudenhallinnan heterogeenisissa verkoissa, joissa palvelunlaatu vaihtelee. Väitöskirja myös ehdottaa erilaisia ratkaisuja videopalvelun adaptoinnin ja tiedonsiirron parantamiseksi arkkitehtuuria hyödyntämällä. Näihin lukeutuvat usealle protokollakerrokselle toteutettu videon adaptointi, verkkoyhteyden ruuhkautumiseen reagoiva yhteydensiirto sekä usean verkkoyhteyden samanaikainen käyttö videopalvelun tiedonsiirrossa. Videon adaptoinnissa ja siirrossa hyödynnetään uutta skaalautuvaa videonkoodausteknologiaa, joka mahdollistaa vaaditun, joustavan videobittivirran muokkauksen. Liikkuvuudenhallinnan osalta työssä keskitytään pääosin kehittämään Mobile IP -protokollan päätöksentekoa suoratoistovideopalvelujen tapauksessa. Lopuksi väitöskirjassa esitetään kokonaisvaltainen ja koordinoitu ratkaisu videopalvelun adaptoinnin sekä päätelaitteen liikkuvuuden hallintaan päästä päähän -optimoinnin saavuttamiseksi. Tuloksena esitetyt järjestelmäarkkitehtuuri ja protokollakerrosten välistä tietoa käyttävät hallinta-algoritmit evaluoitiin simulaatioiden ja oikeiden prototyyppien avulla. Tulokset osoittavat, että ehdotettuja menetelmiä voidaan käyttää parantamaan suoratoistovideopalvelujen suorituskykyä heterogeenisissa verkoissa. Ratkaisut vaativat muutoksia verkko- ja palveluarkkitehtuureihin, mutta niiden asteittainen tai osittainen käyttöönotto on mahdollista. Tulokset osoittavat myös protokollakerrosten välisen tiedon tarpeellisuuden langattomien ja heterogeenisten verkkojen tehokkaassa käytössä
30
Semiari, Omid. "Context-Aware Resource Management and Performance Analysis of Millimeter Wave and Sub-6 GHz Wireless Networks." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/86482.
Full textAbstract:
Emerging wireless networks are foreseen as an integration of heterogeneous spectrum bands, wireless access technologies, and backhaul solutions, as well as a large-scale interconnection of devices, people, and vehicles. Such a heterogeneity will range from the proliferation of multi-tasking user devices with different capabilities such as smartphones and tablets to the deployment of multi-mode access points that can operate over heterogeneous frequency bands spanning both sub-6 GHz microwave and high-frequency millimeter wave (mmW) frequencies bands. This heterogeneous ecosystem will yield new challenges and opportunities for wireless resource management. On the one hand, resource management can exploit user and network-specific context information, such as application type, social metrics, or operator pricing, to develop application-driven, context-aware networks. Similarly, multiple frequency bands can be leveraged to meet the stringent and heterogeneous quality-of-service (QoS) requirements of the new wireless services such as video streaming and interactive gaming. On the other hand, resource management in such heterogeneous, multi-band, and large-scale wireless systems requires distributed frameworks that can effectively utilize all available resources while operating with manageable overhead. The key goal of this dissertation is therefore to develop novel, self-organizing, and low-complexity resource management protocols -- using techniques from matching theory, optimization, and machine learning -- to address critical resource allocation problems for emerging heterogeneous wireless systems while explicitly modeling and factoring diverse network context information.
Towards achieving this goal, this dissertation makes a number of key contributions.
First, a novel context-aware scheduling framework is developed for enabling dual-mode base stations to efficiently and jointly utilize mmW and microwave frequency resources while maximizing the number of user applications whose stringent delay requirements are satisfied.
The results show that the proposed approach will be able to significantly improve the QoS per application and decrease the outage probability. Second, novel solutions are proposed to address both network formation and resource allocation problems in multi-hop wireless backhaul networks that operate at mmW frequencies. The proposed framework motivates collaboration among multiple network operators by resource sharing to reduce the cost of backhauling, while jointly accounting for both wireless channel characteristics and economic factors. Third, a novel framework is proposed to exploit high-capacity mmW communications and device-level caching to minimize handover failures as well as energy consumption by inter-frequency measurements, and to provide seamless mobility in dense heterogeneous mmW-microwave small cell networks (SCNs). Fourth, a new cell association algorithm is proposed, based on matching theory with minimum quota constraints, to optimize load balancing in integrated mmW-microwave networks.
Fifth, a novel medium access control (MAC) protocol is proposed to dynamically manage the wireless local area network (WLAN) traffic jointly over the unlicensed 60 GHz mmW and sub-6 GHz bands to maximize the saturation throughput and minimize the delay experienced by users.
Finally, a novel resource management approach is proposed to optimize device-to-device (D2D) communications and improve traffic offload in heterogeneous wireless SCNs by leveraging social context information that is dynamically learned by the network. In a nutshell, by providing novel, context-aware, and self-organizing frameworks, this dissertation addresses fundamentally challenging resource management problems that mainly stem from large scale, stringent service requirements, and heterogeneity of next-generation wireless networks.<br>Ph. D.
31
Tomic, David. "Service Aware Traffic Distribution in Heterogeneous A2G Networks." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-248995.
Full textAbstract:
Airplanes have different ways to connect to the ground, including satellite air-to-ground communication (SA2GC) and direct air-to-ground communication (DA2GC). Each connection/link offers a different varying amount of transmission capacity over flight time. The traffic generated in the airplane must be forwarded/sent to ground over the available links. It is however not clear how the traffic should be forwarded so that traffic quality of service (QoS) requirements are met. The thesis at hand considers this question, and implements an algorithm handling the forwarding decision with three different forwarding schemes. Those consider traffic parameters in calculating a value assigned to each traffic flow, over a combination of priority, delay requirement and the number of times a traffic flow is dropped. The forwarding algorithm relies on proposed in-flight broadband connectivity (IFBC) network traffic and air-to-ground (A2G) link models, which aim at approximating the network environment of future IFBC networks. It is shown that QoS requirements of traffic flows in terms of packet loss and delay cannot be satisfied with capacities offered by current DA2GC and SA2GC technology. For a future scenario, with higher assumed link capacities, the QoS requirements are met to a higher extent. This is shown in lower packet loss and delay experienced by the respective traffic flows. Further, it is shown that the performance can be improved with specific forwarding schemes used by the forwarding algorithm. It is also investigated how a web cache can be used as a fallback technology. For this a required web cache hit rate is found, which should be high enough to offload the network with content served from the cache. Overall, the thesis aims at proposing an efficient traffic forwarding technique, and at giving insight into an alternative if this technique fails.<br>Flygplan har olika sätt att ansluta till marken, inklusive satellit-mark-kommunikation (SA2GC) och direkt luft till markkommunikation (DA2GC). Varje anslutning/länk erbjuder en annan varierande mängd överföringskapacitet under flygtid. Den trafik som genereras i flygplanet måste vidarebefordras/skickas till marken över de tillgängliga länkarna. Det är emellertid inte klart hur trafiken ska vidarebefordras så att trafiksäkerhetskvaliteten (QoS) uppfylls. Avhandlingen handlar om denna fråga och implementerar en algoritm som hanterar vidarebefordringsbeslutet med tre olika vidarebefordringssystem. De betraktar trafikparametrar vid beräkning av ett värde som tilldelas varje trafikflöde, över en kombination av prioritet, fördröjningskrav och antalet gånger ett trafikflöde tappas. Vidarebefordringsalgoritmen är beroende av föreslagna bredbandsförbindelser (IFBC) i nätverk och A2G-länkmodeller, som syftar till att approximera nätverksmiljön för framtida IFBC-nätverk. Det visas att QoS-krav på trafikflöden när det gäller paketförlust och fördröjning inte kan tillgodoses med kapacitet som erbjuds av nuvarande DA2GC- och SA2GC-teknik. För ett framtida scenario, med högre antagna länkkapacitet, uppfylls QoS-kraven i högre utsträckning. Detta visas med lägre paketförlust och fördröjning som upplevs av respektive trafikflöden. Vidare är det visat att prestanda kan förbättras med specifika vidarekopplingsscheman som används av vidarebefordringsalgoritmen. Det undersöks också hur en webbcache kan användas som en återgångsteknik. För detta hittas en obligatorisk webbcache-träfffrekvens, som bör vara tillräckligt hög för att ladda upp nätverket med innehåll som serveras från cacheminnet. Sammanfattningsvis syftar uppsatsen till att föreslå en effektiv trafiköverföringsteknik och att ge insikt om ett alternativ om denna teknik misslyckas.
32
Sharif, Atif. "Reliable, congestion aware transport layer protocol for heterogeneous wireless sensor networks." Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/87.
Full textAbstract:
Energy is the biggest concern for any heterogeneous WSNs and achieving high energy efficiency is of paramount importance for the longevity of a heterogeneous WSNs. Communicating in- formation from the sensing region to the sink is a critical task in the entire operation of a heterogeneous WSNs. Such information needs to be reliably communicated, while avoiding any network congestion, from source to sink in order to ensure that application-specific Quality of Service objectives are met for any given scenario. This thesis developed several transport layer protocols to address the issues of congestion control, reliability assurance, simultaneously supporting heterogeneous traffic environment and energy efficiency for a heterogeneous WSNs.The first aim of the proposed research is to develop a congestion control scheme for a heterogeneous WSNs. The envisaged congestion control scheme has dual functionality. Firstly, it should be capable of handling the traffic heterogeneity and secondly, it intelligently assigns the source transmission rates and channel bandwidth for avoiding congested scenarios within the network, thereby avoiding any unnecessary packet retransmissions, due to packet drops caused by congestion. This produces high network good throughput, effective use of channel bandwidth, minimum E-2-E data packet latency etc. All the proposed transport layer protocol schemes e.g. End-to-End Reliable and Congestion Aware Transport Layer Protocol (ERCTP), Lightweight Congestion Aware Reliable Transport protocol (LCART) and Lightweight Congestion Aware Reliable Transport Protocol-implicit (LCARTi) are designed with this aim in mind.The second aim of the proposed research is to develop an intelligent reliability ensuring scheme capable of handling bidirectional reliability issues associated with data and control information flow within the heterogeneous WSNs. The design takes into account the variable nature of reliability assurance based on the nature of the traffic. For instance, multimedia flow is given a high reliability measure in comparison to scalar and non-event information flow, since the multimedia has a high retransmission cost. All the proposed transport layer protocol schemes such as ERCTP, LCART and LCARTi are designed in order to achieve this objective.The third aim of the proposed research is to develop a scheme that simultaneously handles the heterogeneous traffic flows within the same network. The proposed scheme has the intelligence to determine the nature of traffic and to allocate different bandwidth based on this nature in order to meet the stringent requirements as imposed by the application-specific QoS constraints like E-2-E data packet latency, high good throughput etc. All the proposed transport layer protocol schemes such as ERCTP, LCART and LCARTi are designed with this objective in mind.The fourth and final aim of the proposed research is to create a mechanism that merges the common functionalities of different layers of the WSNs communication stack in order to maximise energy efficiency. This involves finding the relationship between the transport and the lower MAC and wireless-physical layers of the WSNs communication stack. This merging will result in better utilization of network resources such as bandwidth, storage etc. and helps to achieve the objective of energy efficiency. Only the LCART and LCARTi designs achieve this proposed research aim.
33
Hossmann-Picu, Andreea [Verfasser]. "Delay Tolerant Networks with Heterogeneous Mobility: Models and Implications for Algorithms / Andreea Hossmann-Picu." Aachen : Shaker, 2014. http://d-nb.info/1059344637/34.
Full text
34
Simsek, Meryem [Verfasser]. "Learning Based Techniques for Intercell Interference Coordination in LTE-Advanced Heterogeneous Networks / Meryem Simsek." Aachen : Shaker, 2013. http://d-nb.info/1050343530/34.
Full text
35
SHAPOVAL, ILLYA. "Adaptive Scheduling Applied to Non-Deterministic Networks of Heterogeneous Tasks for Peak Throughput in Concurrent Gaudi." Doctoral thesis, Università degli studi di Ferrara, 2016. http://hdl.handle.net/11392/2403399.
Full textAbstract:
Come la e-Science rivoluziona il metodo scientifico nella sua ricerca empirica e teoria scientifica, altrettanto pone una crescente sfida per l'accelerato flusso di dati prodotto. La fisica delle alte energie (HEP, High Energy Physics) è un rappresentante prominente di scienza che usa grandi quantità di dati, e richiede software scalabile e con un alto throughput per essere in grado di sostenere le richieste computazionali associate. Uno spiccato esempio è Gaudi, un framework software indipendente dall'esperimento usato da molti esperimenti di HEP. Tra questi ci sono ATLAS ed LHCb, due dei quattro esperimenti principali presso il Large Hadron Collider (LHC) del CERN, il Laboratorio Europeo per la Fisica delle Particelle. Gaudi è attualmente oggetto di una rivoluzione architetturale mirata al processamento massivamente concorrente e adattivo dei dati.
In questo lavoro esploro le nuove dimensioni del miglioramento delle performance per la prossima generazione di Gaudi. Propongo quindi un complesso di soluzioni di scheduling dei task per la massimizzazione adattiva e non intrusiva del throughput nell'implementazione concorrente di Gaudi basata su task multithread. Inizialmente presento un sistema di controllo della concorrenza, reattivo e basato su grafi, per la risoluzione della precedenza dei task, con bassa latenza e scalabile in condizioni non predicibili di processamento dei dati. In seconda istanza, dimostro l'eccezionale potenziale dello scheduling proattivo dei task, che utilizza tecniche di livellamento della concorrenza attraverso l'induzione di valanghe di task, per massimizzare il throughput in condizioni di regole di precedenza stringenti. Infine, investigo la sinergia di uno scheduling dei task che ignora la latenza con una oversubscription controllata dei processori centrali. Dimostro che questa combinazione ha un potenziale significativo per la massimizzazione del throughput in generale e in particolare per l'adozione del paradigma del computing eterogeneo nell'ambito di Gaudi. Tutte le idee sono supportate da esempi basati sulla ricostruzione di eventi di LHCb.<br>As much the e-Science revolutionizes the scientific method in its empirical research and scientific theory, as it does pose the ever growing challenge of accelerating data deluge. The high energy physics (HEP) is a prominent representative of the data intensive science and requires scalable high-throughput software to be able to cope with associated computational endeavors. One such striking example is Gaudi – an experiment independent software frame work, used in several frontier HEP experiments. Among them stand ATLAS and LHCb – two of four mainstream experiments at the Large Hadron Collider (LHC) at CERN, the European Laboratory for Particle Physics. The framework is currently undergoing an architectural revolution aiming at massively concurrent and adaptive data processing.
In this work I explore new dimensions of performance improvement for the next generation Gaudi. I then propose a complex of generic task scheduling solutions for adaptive and non-intrusive throughput maximization in multithreaded task-based realization of Gaudi. Firstly, I present the reactive graph-based concurrency control system for low latency and scalable task precedence resolution in unpredictable data processing conditions. Secondly, I demonstrate the outstanding potential of the proactive task scheduling approach that employs the technique of induced avalanche concurrency leveling for throughput maximization in conditions of tight task precedence constraints. Finally, I investigate the synergy of latency oblivious task scheduling and controlled oversubscription of central processors. I prove a significant potential of this merger for throughput maximization in general and for adoption of the paradigm of heterogeneous computing in the context of Gaudi in particular. I exemplify all ideas in the LHCb event reconstruction scenario.
36
GIANSANTI, VALENTINA. "Integration of heterogeneous single cell data with Wasserstein Generative Adversarial Networks." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/404516.
Full textAbstract:
Tessuti, organi e organismi sono sistemi biologici complessi, oggetto di studi che mirano alla caratterizzazione dei loro processi biologici. Comprendere il loro funzionamento e la loro interazione in campioni sani e malati consente di interferire, correggere e prevenire le disfunzioni dalle quali si sviluppano possibilmente le malattie.
I recenti sviluppi nelle tecnologie di sequenziamento single-cell stanno ampliano la capacità di profilare, a livello di singola cellula, diversi layer molecolari (trascrittoma, genoma, epigenoma, proteoma). Il numero, la grandezza e le diverse modalità dei dataset prodotti è in continua crescita. Ciò spinge allo sviluppo di robusti metodi per l’integrazione di dataset multiomici, che siano essi descrittivi o meno delle stesse cellule. L’integrazione di più fonti di informazione produce una descrizione più ampia e completa dell’intero sistema analizzato.
La maggior parte dei sistemi di integrazione disponibili ad oggi consente l’analisi simultanea di un numero limitato di omiche (generalmente due) e richiede conoscenze pregresse riguardo le loro relazioni. Questi metodi spesso impongono la traduzione di una modalità nelle variabili espresse da un altro dato (ad esempio, i picchi di ATAC vengono convertiti in gene activity matrix). Questo step introduce un livello di approssimazione nel dato che potrebbe pregiudicare le analisi svolte in seguito.
Da qui nasce MOWGAN (Multi Omic Wasserstein Generative Adversarial Network), un framework basato sul deep-learning, per la simulazione di dati multimodali appaiati in grado di supportare un alto numero di dataset (più di due) e agnostico sulle relazioni che intercorrono tra loro (non viene imposta alcuna assunzione).
Ogni modalità viene proiettata in uno spazio descrittivo ridotto, le cui dimensioni sono fissate per tutti i datasets. Questo processo previene la traduzione tra modalità. Le cellule, descritte da vettori nello spazio ridotto, vengono ordinate in base alla prima componente della loro Laplacian Eigenmap. Un regressore Bayesian viene successivamente applicato per selezionare i mini-batch con i quali viene allenata una particolare architettura di deep-learning, la Wasserstein Generative Adversarial Network with gradient penalty.
La componente generativa della rete restituisce in uscita un nuovo dataset, appaiato, che viene utilizzato come ponte per il passaggio di informazioni tra i dataset originali.
Lo sviluppo di MOWGAN è stato condotto con l’ausilio di dati pubblici per i quali erano disponibili osservazioni di RNA e ATAC sia per le stesse cellule, che per cellule differenti. La valutazione dei risultati è stata condotta sulla base della capacità del dato prodotto di essere integrato con il dato originale. Inoltre, il dato sintetico deve avere informazione condivisa tra le diverse omiche. Questa deve rispettare la natura biologica del dato: le associazioni non devono essere presenti tra entità cellulari rappresentanti tipi cellulari differenti.
L’organizzazione del dato in mini-batch consente a MOWGAN di avere una architettura di rete indipendente dal numero di modalità considerate. Infatti, il framework è stato applicato anche per l’integrazione di tre (RNA, ATAC e proteine, RNA ATAC e modificazioni istoniche) e quattro modalità (RNA, ATAC, proteine e modificazioni istoniche).
Il rendimento di MOWGAN è stato dunque valutato in termini di scalabilità computazionale (integrazione di molteplici datasets) e significato biologico, essendo quest’ultimo il più importante per non giungere a conclusioni errate nello studio in essere. È stato eseguito un confronto con altri metodi già disponibili in letteratura, riscontrando la maggiore capacità di MOWGAN di creare associazioni inter-modali tra entità cellulari realmente legate.
In conclusione, MOWGAN è uno strumento potente per l’integrazione di dati multi-modali in single-cell, che risponde a molte delle problematiche riscontrate nel campo.<br>Tissues, organs and organisms are complex biological systems. They are objects of many studies aiming at characterizing their biological processes. Understanding how they work and how they interact in healthy and unhealthy samples gives the possibility to interfere, correcting and preventing dysfunctions, possibly leading to diseases.
Recent advances in single-cell technologies are expanding our capabilities to profile at single-cell resolution various molecular layers, by targeting the transcriptome, the genome, the epigenome and the proteome. The number of single-cell datasets, their size and the diverse modalities they describe is continuously increasing, prompting the need to develop robust methods to integrate multiomic datasets, whether paired from the same cells or, most challenging, from unpaired separate experiments. The integration of different source of information results in a more comprehensive description of the whole system.
Most published methods allow the integration of limited number of omics (generally two) and make assumptions about their inter-relationships. They often impose the conversion of a data modality into the other one (e.g., ATAC peaks converted in a gene activity matrix). This step introduces an important level of approximation, which could affect the analysis later performed.
Here we propose MOWGAN (Multi Omic Wasserstein Generative Adversarial Network), a deep-learning based framework to simulate paired multimodal data supporting high number of modalities (more than two) and agnostic about their relationships (no assumption is imposed). Each modality is embedded into feature spaces with same dimensionality across all modalities. This step prevents any conversion between data modalities. The embeddings are sorted based on the first Laplacian Eigenmap. Mini-batches are selected by a Bayesian ridge regressor to train a Wasserstein Generative Adversarial Network with gradient penalty.
The output of the generative network is used to bridge real unpaired data.
MOWGAN was prototyped on public data for which paired and unpaired RNA and ATAC experiments exists. Evaluation was conducted on the ability to produce data integrable with the original ones, on the amount of shared information between synthetic layers and on the ability to impose association between molecular layers that are truly connected.
The organization of the embeddings in mini-batches allows MOWGAN to have a network architecture independent of the number of modalities evaluated. Indeed, the framework was also successfully applied to integrate three (e.g., RNA, ATAC and protein or histone modification data) and four modalities (e.g., RNA, ATAC, protein, histone modifications).
MOWGAN’s performance was evaluated in terms of both computational scalability and biological meaning, being the latter the most important to avoid erroneous conclusion. A comparison was conducted with published methods, concluding that MOWGAN performs better when looking at the ability to retrieve the correct biological identity (e.g., cell types) and associations.
In conclusion, MOWGAN is a powerful tool for multi-omics data integration in single-cell, which answer most of the critical issues observed in the field.
37
Sun, Yingcheng. "Topic Modeling and Spam Detection for Short Text Segments in Web Forums." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1575281495398615.
Full text
38
Yang, Jin [Verfasser], Kai-Uwe [Akademischer Betreuer] Sattler, Jochen [Akademischer Betreuer] Seitz, and Lim [Akademischer Betreuer] Lipyeow. "Decentralized data fusion and data harvesting framework for heterogeneous dynamic network systems / Jin Yang. Betreuer: Kai-Uwe Sattler. Gutachter: Jochen Seitz ; Lim Lipyeow." Ilmenau : Universitätsbibliothek Ilmenau, 2015. http://d-nb.info/1079840486/34.
Full text
39
Rückelt, Tobias [Verfasser], Ralf [Akademischer Betreuer] Steinmetz, and Ioannis [Akademischer Betreuer] Stavrakakis. "Connecting Vehicles to the Internet - Strategic Data Transmission for Mobile Nodes using Heterogeneous Wireless Networks / Tobias Rückelt ; Ralf Steinmetz, Ioannis Stavrakakis." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1147968365/34.
Full text
40
Toseef, Umar [Verfasser], Carmelita [Akademischer Betreuer] Görg, and Christian [Akademischer Betreuer] Wietfeld. "LTE Optimization and Resource Management in Wireless Heterogeneous Networks / Umar Toseef. Gutachter: Carmelita Görg ; Christian Wietfeld. Betreuer: Carmelita Görg." Bremen : Staats- und Universitätsbibliothek Bremen, 2013. http://d-nb.info/1072047926/34.
Full text
41
Finke, Thomas [Verfasser], Jochen [Akademischer Betreuer] Seitz, Andreas [Gutachter] Mitschele-Thiel, and Jürgen [Gutachter] Schröder. "SEREMA : Self-Organized Routing in Heterogeneous Mobile Ad Hoc Networks / Thomas Finke ; Gutachter: Andreas Mitschele-Thiel, Jürgen Schröder ; Akademischer Betreuer: Jochen Seitz." Ilmenau : Universitätsbibliothek Ilmenau, 2017. http://d-nb.info/114171387X/34.
Full text
42
Kaya, Muammer Ozge. "A Complex Event Processing Framework Implementation Using Heterogeneous Devices In Smart Environments." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614152/index.pdf.
Full textAbstract:
Significant developments in microprocessor and sensor technology make wirelessly connected small computing devices widely available<br>hence they are being used frequently to collect data from the environment. In this study, we construct a framework in order to extract high level information in an environment containing such pervasive computing devices. In the framework, raw data originating from wireless sensors are collected using an event driven system and converted to simple events for transmission over a network to a central processing unit. We also utilize complex event processing approach incorporating temporal constraints, aggregation and sequencing of events in order to define complex events for extracting high level information from the collected simple events. We develop a prototype using easily accessible hardware and set it up in a classroom within our university. The results demonstrate the feasibility of our approach, ease of deployment and successful application of the complex event processing framework.
43
Nguyen, The An Binh [Verfasser], Ralf [Akademischer Betreuer] Steinmetz, and Michael [Akademischer Betreuer] Zink. "Quality-aware Tasking in Mobile Opportunistic Networks - Distributed Information Retrieval and Processing utilizing Opportunistic Heterogeneous Resources. / The An Binh Nguyen ; Ralf Steinmetz, Michael Zink." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2018. http://d-nb.info/1167926331/34.
Full text
44
Krug, Silvia Verfasser], Jochen [Akademischer Betreuer] [Seitz, Martina [Gutachter] Zitterbart, and Lars [Gutachter] Wolf. "H3N - analysis toolbox for hybrid routing in heterogeneous, disruption-tolerant first responder ad hoc networks / Silvia Krug ; Gutachter: Martina Zitterbart, Lars Wolf ; Betreuer: Jochen Seitz." Ilmenau : TU Ilmenau, 2017. http://d-nb.info/1178134814/34.
Full text
45
Schellenberg, Sebastian [Verfasser], Jochen [Akademischer Betreuer] Seitz, Andreas [Akademischer Betreuer] Mitschele-Thiel, and Mainak [Akademischer Betreuer] Chatterjee. "Naming and Address Resolution in Heterogeneous Mobile Ad hoc Networks / Sebastian Schellenberg. Betreuer: Jochen Seitz. Gutachter: Andreas Mitschele-Thiel ; Mainak Chatterjee." Ilmenau : Universitätsbibliothek Ilmenau, 2016. http://d-nb.info/1096221098/34.
Full text
46
Göndör, Sebastian Jürg [Verfasser], Axel [Akademischer Betreuer] Küpper, Axel [Gutachter] Küpper, Ulrik [Gutachter] Schroeder, and Maurizio [Gutachter] Marchese. "Seamless interoperability and data portability in the social web for facilitating an open and heterogeneous online social network federation / Sebastian Jürg Göndör ; Gutachter: Axel Küpper, Ulrik Schroeder, Maurizio Marchese ; Betreuer: Axel Küpper." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1164076280/34.
Full text
47
Gonzalez, Gamboa Vladimir [Verfasser], Rainer [Akademischer Betreuer] Marggraf, Heiko [Akademischer Betreuer] Faust, and Karin [Akademischer Betreuer] Kurz. "Social Network Patterns of Sharing Information on Land Use and Agricultural Innovations in Ethnically Heterogeneous Communities in Ecuador / Vladimir Gonzalez Gamboa. Gutachter: Heiko Faust ; Karin Kurz. Betreuer: Rainer Marggraf." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1048219755/34.
Full text
48
Martignano, Anna. "Real-time Anomaly Detection on Financial Data." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-281832.
Full textAbstract:
This work presents an investigation of tailoring Network Representation Learning (NRL) for an application in the Financial Industry. NRL approaches are data-driven models that learn how to encode graph structures into low-dimensional vector spaces, which can be further exploited by downstream Machine Learning applications. They can potentially bring a lot of benefits in the Financial Industry since they extract in an automatic way features that can provide useful input regarding graph structures, called embeddings. Financial transactions can be represented as a network, and through NRL, it is possible to extract embeddings that reflect the intrinsic inter-connected nature of economic relationships. Such embeddings can be used for several purposes, among which Anomaly Detection to fight financial crime.This work provides a qualitative analysis over state-of-the-art NRL models, which identifies Graph Convolutional Network (ConvGNN) as the most suitable category of approaches for Financial Industry but with a certain need for further improvement. Financial Industry poses additional challenges when modelling a NRL solution. Despite the need of having a scalable solution to handle real-world graph with considerable dimensions, it is necessary to take into consideration several characteristics: transactions graphs are inherently dynamic since every day new transactions are executed and nodes can be heterogeneous. Besides, everything is further complicated by the need to have updated information in (near) real-time due to the sensitivity of the application domain. For these reasons, GraphSAGE has been considered as a base for the experiments, which is an inductive ConvGNN model. Two variants of GraphSAGE are presented: a dynamic variant whose weights evolve accordingly with the input sequence of graph snapshots, and a variant specifically meant to handle bipartite graphs. These variants have been evaluated by applying them to real-world data and leveraging the generated embeddings to perform Anomaly Detection. The experiments demonstrate that leveraging these variants leads toimagecomparable results with other state-of-the-art approaches, but having the advantage of being suitable to handle real-world financial data sets.<br>Detta arbete presenterar en undersökning av tillämpningar av Network Representation Learning (NRL) inom den finansiella industrin. Metoder inom NRL möjliggör datadriven kondensering av grafstrukturer till lågdimensionella och lätthanterliga vektorer.Dessa vektorer kan sedan användas i andra maskininlärningsuppgifter. Närmare bestämt, kan metoder inom NRL underlätta hantering av och informantionsutvinning ur beräkningsintensiva och storskaliga grafer inom den finansiella sektorn, till exempel avvikelsehantering bland finansiella transaktioner. Arbetet med data av denna typ försvåras av det faktum att transaktionsgrafer är dynamiska och i konstant förändring. Utöver detta kan noderna, dvs transaktionspunkterna, vara vitt skilda eller med andra ord härstamma från olika fördelningar.I detta arbete har Graph Convolutional Network (ConvGNN) ansetts till den mest lämpliga lösningen för nämnda tillämpningar riktade mot upptäckt av avvikelser i transaktioner. GraphSAGE har använts som utgångspunkt för experimenten i två olika varianter: en dynamisk version där vikterna uppdateras allteftersom nya transaktionssekvenser matas in, och en variant avsedd särskilt för bipartita (tvådelade) grafer. Dessa varianter har utvärderats genom användning av faktiska datamängder med avvikelsehantering som slutmål.
49
Exposito, Victor. "Réseaux de multidiffusion avec coopération interactive entre récepteurs." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC006.
Full textAbstract:
La présente thèse s’intéresse aux communications descendantes, plus spécifiquement aux canaux de multidiffusion, pour lesquels un émetteur diffuse un message commun destiné à tous les utilisateurs d’un groupe. Pour que le débit ne soit pas limité par le plus faible utilisateur en terme de qualité de canal, différentes solutions reposant sur des techniques entrées multiples sorties multiples massives ou multi-débit ont été proposées dans la littérature. Cependant, si tous les utilisateurs souhaitaient obtenir le même niveau de qualité, le plus faible utilisateur établirait le débit et/ou nécessiterait une quantité de ressources démesurée, ce qui impacterait tout le groupe. Les études récentes portant sur les communications d’appareil à appareil ouvrent la voie à la coopération entre utilisateurs proches, ce qui pourrait bénéficier à tous les utilisateurs, en garantissant le même niveau de qualité tout en maintenant un faible coût en ressource et en énergie. C’est pour ces raisons que cette thèse s’intéresse aux canaux de multidiffusion avec coopération entre récepteurs. La théorie de l’information formalise l’étude de ces réseaux et fournit des bornes universelles portant sur le débit transmissible. Le schéma de coopération proposé se base sur une superposition appropriée d’opérations de compresse-relaie (CF) et décode-relaie (DF), et il est prouvé que ses performances surpasse celles des schémas de coopérations non-interactifs pour le scénario à deux récepteurs. Les propriétés de la coopération interactive émergent de l’asymétrie de construction du schéma de coopération, ce qui permet d’adapter l’ordre des CFs et DFs en fonction de la qualité du canal. L’idée derrière cette interaction, les intuitions concernant les points clés de la construction, et des résultats numériques sont donnés pour des réseaux de petites tailles. Des simulations au niveau du système illustrent le gain potentiel que la coopération entre récepteurs pourrait apporter pour des réseaux de plus grandes tailles<br>The present thesis concentrates on downlink communications. In order to tackle one part of this challenging problem, we focus on the multicast channel in which one transmitter broadcasts a common message intended to a whole group of users. To ensure that the transmission rate is not limited by the weakest user in terms of channel quality, different solutions using massive multiple-input multiple-output or multirate strategies have been proposed in the literature. However, if all users wish to obtain the same content quality, the weakest user would set the rate and/or require a disproportionate amount of resource, and thus impact the whole group. With the recent study of device-to-device mechanisms, user cooperation in close proximity becomes possible and would benefit to all users by ensuring the same content quality while maintaining a low cost in terms of amount of resource and energy. Consequently, this thesis is centered around the multicast network with receiver cooperation. Information-theoretic tools formalize the study of the network considered and provide general bounds on the achievable transmission rate. The proposed cooperation scheme is based on an appropriate superposition of compress-forward (CF) and decode-forward (DF) operations, and provenly outperform non-interactive schemes in the two-receiver scenario. Properties of the interactive cooperation emerge from the asymmetric construction of the scheme which permits to adapt the order of CFs and DFs according to the channel condition. The core idea of the interaction, some insights on key construction points, and numerical results are given for small size networks. System level simulations illustrate the potential gain of receiver cooperation for larger networks
50
PETRINI, ALESSANDRO. "HIGH PERFORMANCE COMPUTING MACHINE LEARNING METHODS FOR PRECISION MEDICINE." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/817104.
Full textAbstract:
La Medicina di Precisione (Precision Medicine) è un nuovo paradigma che sta rivoluzionando diversi aspetti delle pratiche cliniche: nella prevenzione e diagnosi, essa è caratterizzata da un approccio diverso dal "one size fits all" proprio della medicina classica. Lo scopo delle Medicina di Precisione è di trovare misure di prevenzione, diagnosi e cura che siano specifiche per ciascun individuo, a partire dalla sua storia personale, stile di vita e fattori genetici.
Tre fattori hanno contribuito al rapido sviluppo della Medicina di Precisione: la possibilità di generare rapidamente ed economicamente una vasta quantità di dati omici, in particolare grazie alle nuove tecniche di sequenziamento (Next-Generation Sequencing); la possibilità di diffondere questa enorme quantità di dati grazie al paradigma "Big Data"; la possibilità di estrarre da questi dati tutta una serie di informazioni rilevanti grazie a tecniche di elaborazione innovative ed altamente sofisticate.
In particolare, le tecniche di Machine Learning introdotte negli ultimi anni hanno rivoluzionato il modo di analizzare i dati: esse forniscono dei potenti strumenti per l'inferenza statistica e l'estrazione di informazioni rilevanti dai dati in maniera semi-automatica. Al contempo, però, molto spesso richiedono elevate risorse computazionali per poter funzionare efficacemente. Per questo motivo, e per l'elevata mole di dati da elaborare, è necessario sviluppare delle tecniche di Machine Learning orientate al Big Data che utilizzano espressamente tecniche di High Performance Computing, questo per poter sfruttare al meglio le risorse di calcolo disponibili e su diverse scale, dalle singole workstation fino ai super-computer.
In questa tesi vengono presentate tre tecniche di Machine Learning sviluppate nel contesto del High Performance Computing e create per affrontare tre questioni fondamentali e ancora irrisolte nel campo della Medicina di Precisione, in particolare la Medicina Genomica: i) l'identificazione di varianti deleterie o patogeniche tra quelle neutrali nelle aree non codificanti del DNA; ii) l'individuazione della attività delle regioni regolatorie in diverse linee cellulari e tessuti; iii) la predizione automatica della funzione delle proteine nel contesto di reti biomolecolari.
Per il primo problema è stato sviluppato parSMURF, un innovativo metodo basato su hyper-ensemble in grado di gestire l'elevato grado di sbilanciamento che caratterizza l'identificazione di varianti patogeniche e deleterie in mezzo al "mare" di varianti neutrali nelle aree non-coding del DNA. L'algoritmo è stato implementato per sfruttare appositamente le risorse di supercalcolo del CINECA (Marconi - KNL) e HPC Center Stuttgart (HLRS Apollo HAWK), ottenendo risultati allo stato dell'arte, sia per capacità predittiva, sia per scalabilità.
Il secondo problema è stato affrontato tramite lo sviluppo di reti neurali "deep", in particolare Deep Feed Forward e Deep Convolutional Neural Networks per analizzare - rispettivamente - dati di natura epigenetica e sequenze di DNA, con lo scopo di individuare promoter ed enhancer attivi in linee cellulari e tessuti specifici. L'analisi è compiuta "genome-wide" e sono state usate tecniche di parallelizzazione su GPU.
Infine, per il terzo problema è stato sviluppato un algoritmo di Machine Learning semi-supervisionato su grafo basato su reti di Hopfield per elaborare efficacemente grandi network biologici, utilizzando ancora tecniche di parallelizzazione su GPU; in particolare, una parte rilevante dell'algoritmo è data dall'introduzione di una tecnica parallela di colorazione del grafo che migliora il classico approccio greedy introdotto da Luby.
Tra i futuri lavori e le attività in corso, viene presentato il progetto inerente all'estensione di parSMURF che è stato recentemente premiato dal consorzio Partnership for Advance in Computing in Europe (PRACE) allo scopo di sviluppare ulteriormente l'algoritmo e la sua implementazione, applicarlo a dataset di diversi ordini di grandezza più grandi e inserire i risultati in Genomiser, lo strumento attualmente allo stato dell'arte per l'individuazione di varianti genetiche Mendeliane. Questo progetto è inserito nel contesto di una collaborazione internazionale con i Jackson Lab for Genomic Medicine.<br>Precision Medicine is a new paradigm which is reshaping several aspects of clinical practice, representing a major departure from the "one size fits all" approach in diagnosis and prevention featured in classical medicine. Its main goal is to find personalized prevention measures and treatments, on the basis of the personal history, lifestyle and specific genetic factors of each individual.
Three factors contributed to the rapid rise of Precision Medicine approaches: the ability to quickly and cheaply generate a vast amount of biological and omics data, mainly thanks to Next-Generation Sequencing; the ability to efficiently access this vast amount of data, under the Big Data paradigm; the ability to automatically extract relevant information from data, thanks to innovative and highly sophisticated data processing analytical techniques.
Machine Learning in recent years revolutionized data analysis and predictive inference, influencing almost every field of research.
Moreover, high-throughput bio-technologies posed additional challenges to effectively manage and process Big Data in Medicine, requiring novel specialized Machine Learning methods and High Performance Computing techniques well-tailored to process and extract knowledge from big bio-medical data.
In this thesis we present three High Performance Computing Machine Learning techniques that have been designed and developed for tackling three fundamental and still open questions in the context of Precision and Genomic Medicine: i) identification of pathogenic and deleterious genomic variants among the "sea" of neutral variants in the non-coding regions of the DNA; ii) detection of the activity of regulatory regions across different cell lines and tissues; iii) automatic protein function prediction and drug repurposing in the context of biomolecular networks.
For the first problem we developed parSMURF, a novel hyper-ensemble method able to deal with the huge data imbalance that characterizes the detection of pathogenic variants in the non-coding regulatory regions of the human genome. We implemented this approach with highly parallel computational techniques using supercomputing resources at CINECA (Marconi – KNL) and HPC Center Stuttgart (HLRS Apollo HAWK), obtaining state-of-the-art results.
For the second problem we developed Deep Feed Forward and Deep Convolutional Neural Networks to respectively process epigenetic and DNA sequence data to detect active promoters and enhancers in specific tissues at genome-wide level using GPU devices to parallelize the computation.
Finally we developed scalable semi-supervised graph-based Machine Learning algorithms based on parametrized Hopfield Networks to process in parallel using GPU devices large biological graphs, using a parallel coloring method that improves the classical Luby greedy algorithm.
We also present ongoing extensions of parSMURF, very recently awarded by the Partnership for Advance in Computing in Europe (PRACE) consortium to further develop the algorithm, apply them to huge genomic data and embed its results into Genomiser, a state-of-the-art computational tool for the detection of pathogenic variants associated with Mendelian genetic diseases, in the context of an international collaboration with the Jackson Lab for Genomic Medicine.