Jari Saramäki
Aalto University
AlgorithmPhysicsStatistical physicsCommunity structureInterpersonal tiesWeighted networkArtificial intelligencePsychologyPattern recognitionMaterials scienceData scienceMobile phoneMathematicsComplex networkComputer scienceComplex systemCrystalTheoretical computer scienceSocial networkBiology
183Publications
47H-index
9,732Citations
Publications 150
Newest
#2Talayeh AledavoodH-Index: 7
Last. Sam G. B. Roberts (LJMU: Liverpool John Moores University)H-Index: 18
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The frequency of mobile communication is often used as an indicator of the strength of a tie between two individuals, but how mobile communication relates to other forms of behaving close in social relationships is poorly understood. We used a unique multi-channel 10-month dataset from 510 participants to examine how the frequency of mobile communication was related to the frequency of face-to-face interaction, as measured by Bluetooth scans between the participants mobile phones. The number of ...
Abstract Redesigns of public transport networks are complex undertakings requiring a careful balancing of several conflicting perspectives (e.g., user requirements vs system performance) and aims (e.g., increasing spatial coverage, increasing frequency). Current assessment tools omit an explicit focus on navigability, often identified as a key aspect of the user perspective. For understanding the multidimensional perspective of navigability, this research introduces an assessment framework with ...
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#1Nelli Heikkilä (UH: University of Helsinki)H-Index: 5
#2Silja Sormunen (Aalto University)H-Index: 1
Last. T. Petteri Arstila (UH: University of Helsinki)H-Index: 17
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The T-cell receptor (TCR) repertoire is generated in a semistochastic process of gene recombination and pairing of TCRα to TCRβ chains with the estimated total TCR diversity of >108. Despite this high diversity, similar or identical TCR chains are found to recur in immune responses. Here, we analyzed the thymic generation of TCR sequences previously associated with recognition of self- and nonself-antigens, represented by sequences associated with autoimmune diabetes and HIV, respectively. Unexp...
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#1Nelli Heikkilä (UH: University of Helsinki)H-Index: 5
#2Iivari Kleino (UH: University of Helsinki)H-Index: 9
Last. T. Petteri Arstila (UH: University of Helsinki)H-Index: 17
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Abstract T cell receptor (TCR) is a heterodimer consisting of TCRα and TCRβ chains that are generated by somatic recombination of multiple gene segments. Nascent TCR repertoire undergoes thymic selections where non-functional and potentially autoreactive receptors are removed. During the last years, the development of high-throughput sequencing technology has allowed a large scale assessment of TCR repertoire and multiple analysis tools are now also available. In our recent manuscript, Human thy...
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#1Javier Ureña-Carrion (Aalto University)H-Index: 2
#2Jari Saramäki (Aalto University)H-Index: 47
Last. Mikko Kivelä (Aalto University)H-Index: 17
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Even though the concept of tie strength is central in social network analysis, it is difficult to quantify how strong social ties are. One typical way of estimating tie strength in data-driven studies has been to simply count the total number or duration of contacts between two people. This, however, disregards many features that can be extracted from the rich data sets used for social network reconstruction. Here, we focus on contact data with temporal information. We systematically study how f...
4 CitationsSource
#1Kestutis BaltakysH-Index: 12
#2Juho KanniainenH-Index: 14
Last. Mikko Kivelä (Aalto University)H-Index: 17
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Investors in stock markets distribute their limited attention across different securities. Drawing on recent findings on social behavior, we ask whether there are persistent, characteristic patterns in how household investors distribute their attention. Our study builds on a large data set that contains every transaction of hundreds of thousands of households in a stock market for over 20 years. We find that the ways how investors distribute their attention are not only distinctive, but invarian...
3 CitationsSource
#1Nelli Heikkilä (UH: University of Helsinki)H-Index: 5
#2Reetta Vanhanen (UH: University of Helsinki)H-Index: 4
Last. T. Petteri Arstila (UH: University of Helsinki)H-Index: 17
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Abstract A highly diverse repertoire of T cell antigen receptors (TCR) is created in the thymus by recombination of gene segments and the insertion or deletion of nucleotides at the junctions. Using next-generation TCR sequencing we define here the features of recombination and selection in the human TCRα and TCRβ locus, and show that a strikingly high proportion of the repertoire is shared by unrelated individuals. The thymic TCRα nucleotide repertoire was more diverse than TCRβ, with 4.1 × 106...
5 CitationsSource
#1Ilkka Kivimäki (UCL: Université catholique de Louvain)H-Index: 8
#2Bram Van Moorter (UCL: Université catholique de Louvain)H-Index: 26
Last. Marco Saerens (UCL: Université catholique de Louvain)H-Index: 28
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2 CitationsSource
#1Talayeh Aledavood (Georgia Institute of Technology)H-Index: 7
#2Ilkka KivimäkiH-Index: 8
Last. Jari SaramäkiH-Index: 47
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Human activities follow daily, weekly, and seasonal rhythms. The emergence of these rhythms is related to physiology and natural cycles as well as social constructs. The human body and biological functions undergo near 24-hour rhythms (circadian rhythms). The frequency of these rhythms is more or less similar across people, but its phase is different. In the chronobiology literature, based on the propensity to sleep at different hours of the day, people are categorized into morning-type, evening...
2 Citations
#1Tuomas Alakörkkö (Aalto University)H-Index: 2
#2Jari Saramäki (Aalto University)H-Index: 47
Human activity follows a circadian rhythm. In online activity, this rhythm is visible both at the level of individuals as well as at the population level from Wikipedia edits to mobile telephone calls. However, much less is known about circadian patterns at the level of network structure, that is, beyond the day-night cycle of the frequency of activity. Here, we study how the temporal connectivity of communication networks changes through the day, focusing on sequences of communication events th...
2 CitationsSource