WebSocket vs WebRTC in the stream overlays of the Streamr Network

The Streamr Network is a decentralized publish-subscribe system. This thesis experimentally compares WebSocket and WebRTC as transport protocols in the system’s d-regular random graph type unstructured stream overlays. The thesis explores common designs for publish-subscribe and decentralized P2P systems. Underlying network protocols including NAT traversal are explored to understand how the WebSocket and WebRTC protocols function. The requirements set for the Streamr Network and how its design and implementations fulfill them are discussed. The design and implementations are validated with the use simulations, emulations and AWS deployed real-world experiments. The performance metrics measured from the real-world experiments are compared to related work. As the implementations using the two protocols are separate incompatible versions, the differences between them was taken into account during analysis of the experiments. Although the WebSocket versions overlay construction is known to be inefficient and vulnerable to churn, it is found to be unintentionally topology aware. This caused the WebSocket stream overlays to perform better in terms of latency. The WebRTC stream overlays were found to be more predictable and more optimized for small payloads as estimates for message propagation delays had a MEPA of 1.24% compared to WebSocket’s 3.98%. Moreover, the WebRTC version enables P2P connections between hosts behind NATs. As the WebRTC version’s overlay construction is more accurate, reliable, scalable, and churn tolerant, it can be used to create intentionally topology aware stream overlays to fully take over the results of the WebSocket implementation

Dissertatio philosophica de terminis metaphysicis: qvam, suffragio ampl. phil. ad Auram chori, in inclyto Fennorum lyceo, moderante viro praclarissimo dn. Gabriel Juslenio, log. & metaph. prof. ord. Pro indipiscendis honoribus in philosophiâ summis, loco horisq[ue] svetis, d. 5 Maji a. 1706. Publicae bonorum censurae defert Johannes Ch. Walstenius, Bor: Fennus

Invocatio: I.N.J.Dedicatio: Johannes Lilienstedt, Ericus Loschiöld, Johannes Wallensteen, Christianus Walstenius, Haqvinus Pihlmann, Andreas Bergius.Arkit: 4 arkintunnuksetonta lehteä, A-D4.Painovuosi nimekkeestä

Dissertationis de usu et applicatione historiae: ad vitam civilem. Caput prooemiale, suffragio amplissimae facultatis philosophicae, in Regia ad Auram Academia, praeside viro admod. rever. celeberrimoque mag. Daniele Juslenio, sacr. l.l. prof. Ab. Eruditorum examini modeste submittet si Deo visum fuerit Aboae, in auditorio maximo d. [ ] 1726. Henricus Hassel, Alandus

Dedicatio: Henricus Hassel vanh.Arkit: A8.Painovuosi nimekkeestä.Olemassa myös variantti, josta puuttuu dedikaatio. HYK:ossa tästä vain nimiölehti

Ex philosophia divina, immutabilitatem Dei: consensu ampl. ord. philosophici in Regiâ Academiâ Aboënsi, sub praesidio viri celeberrimi [et] amplissimi, dn. Gabriel Juslenii, log. & metaph. prof. ord. Pro gradu magisterii ejusq[ue] privilegiis ritè adipiscendis, in collegio eruditorum modestè disputabit Johannes Backman Helsing. Nylandus. Die 1 Decembris anni 1706

Invocatio: I.N.J.Dedicatio: Johannes Gezelius nuor., David Lund, Eljas Backman [ruots. runo], Jacobus Prjntz, Gabriel Gottleben, Petrus Wetter, Baltzar Schultz, Ericus Zander, Aaron Fuldha.Arkit: 4 arkintunnuksetonta lehteä, A-H4.Painovuosi nimekkeestä

Theses theologicas, ob quas H. P. S. ingentem in Russia: passus est persecutionem, ad verbi divini canonem examinatas, consensu maxime reverendae facultatis theologicae in celebri ad Auram Academiae, d. x. Octobris, si Deus voluerit, anni MDCCXXIV, dissertatione publica proponet Daniel Juslenius, l. l. sacr. profess. Aboënsis, respondente S. R. M. alumno Henrico Alano, Henr. f. In auditorio maximo

Invocatio: [hepreaa].Arkit: ):(8.Painovuosi nimekkeestä

Exercitium academicum, de ficu arefacta: ex occasione Matth. 21. & Marc. 11. Quod ex consensu ampliss. facultatis philos. in Acad. Aboënsi sub praesidio admod. reverendi atq[ue] celeberr. viri, mag. Danielis Juslenii, l.l. sacr. prof. reg. [et] ordin. Publico examini modeste submittit Henricus Helsingius Wiburgensis, in audit. maximo die XII Dec. MD.CC.XXIV

Invocatio: Q.B.V.D.T.O.M.Dedicatio: Johannes Gezelius nepos, Georgius Helsingius, Michael Fanth.Grat.: Daniel Juslenius [kr. runo], Pet. Elfwing, Alex. Kepllerus, Joh. Sipelius, Chr. Mart. Seelman, Joh. Nylander [hepr. pr.], Mart. Helsingius [kr. runo], J. Gezelius Larsson [ruots. runo], Ericus Cajanus.Arkit: 8 arkintunnuksetonta lehteä, A8 B2.Painovuosi nimekkeestä

Dissertationem philosophicam, de dependentia causarum secundarum: â causa prima in fieri, esse et operari, cum suffragio ampl. fac. phil. in illustri & inclyta Academia Aboënsi, sub praesidio, viri praeclarissimi dn. Gabriel Juslenii, log. & met. prof. reg. & ord. Candide filosofúnton krísei [kreikkaa] modestè sistit Matthias Limnander Helsingf. Nylandus, die, si Deo videtur, 19 Maji an. M.DCC.VI. In auditorio maximo horis solitis

Invocatio: Deo duce.Dedicatio: David Lund, Andreas Ignatius, Arvidus Alopaeus, Petrus Serlachius, Jacobus Printz, Nicolaus Burtz, Abrahamus Carstenius.Grat.: Gabriel J. Thauvonius.Arkit: 4 arkintunnuksetonta lehteä, A-E4.Painovuosi nimekkeestä

Et consensu ampliss. facult: philosophicae: specimen hoc academicum, de processu cognitionis humanae, sub praesidio viri celeberrimi, m. Gabrielis Juslenii, log. & metaph. in Acad. ad Aoram professoris regu & ord. Publicae bonorum censurae modeste subjicit David Petrejus, in audit. majori, die Junii, 1703

Invocatio: Adfulgente gratia divina.Dedicatio: Johannes Gezelius nuor., Henric Johanson, Benedictus Macrolander.Arkit: 3 arkintunnuksetonta lehteä, A-C4 D3.Painovuosi nimekkeestä.Olemassa myös variantti, jossa dedikaatio vain Johannes Gezelius nuoremmalle

Enhancing transit project decisions with a scenario approach

This thesis explores how multi-criteria decision-making and scenario analysis approaches could be applied to public transportation project evaluation. The literature review section provides background on urban development, transit modes, scenario approach related research and its combined approach with multi-criteria decision analysis (MCDA) methods. The literature review collects and describes some examples of previous use of MCDA and scenarios on public transportation and their evaluation criteria, which support the model building in the case section in this thesis. The case section presents the decision alternatives, which are three different public transportation solutions, whose performance in three distinct scenarios will be evaluated. This evaluation is done by implementing two similar approaches of combining MCDA with scenarios. The case section then presents their outcomes in the form of performance values and ranking of the decision alternatives in each scenario. This is followed by a sensitivity analysis, which tweaks the initial measures of the decision alternatives’ evaluation criteria and compares their effects on the outcomes. The implications from the results highlight the significance of stakeholder involvement when setting the scenario-specific criteria weights. Involving a broad and varied group of stakeholders supports the evaluation of the decision alternatives and leads to a more transparent and credible decision-making process. The thesis provides a practical illustration of how the integration of multi-criteria decision-making and scenario analysis can enhance evaluation and support decision-making in the context of public transportation systems in complex and uncertain urban environments