Online social networks have become a major communication platform, where people share their thoug... more Online social networks have become a major communication platform, where people share their thoughts and opinions about any topic real-time. The short text updates people post in these network contain emotions and moods, which when measured collectively can unveil the public mood at population level and have exciting implications for businesses, governments, and societies. Therefore, there is an urgent need for developing solid methods for accurately measuring moods from large-scale social media data. In this paper, we propose PANAS-t, which measures sentiments from short text updates in Twitter based on a well-established psychometric scale, PANAS (Positive and Negative Affect Schedule). We test the efficacy of PANAS-t over 10 real notable events drawn from 1.8 billion tweets and demonstrate that it can efficiently capture the expected sentiments of a wide variety of issues spanning tragedies, technology releases, political debates, and healthcare.
The problem of identifying rumors is of practical importance especially in online social networks... more The problem of identifying rumors is of practical importance especially in online social networks, since information can diffuse more rapidly and widely than the offline counterpart. In this paper, we identify characteristics of rumors by examining the following three aspects of diffusion: temporal, structural, and linguistic. For the temporal characteristics, we propose a new periodic time series model that considers daily and external shock cycles, where the model demonstrates that rumor likely have fluctuations over time. We also identify key structural and linguistic differences in the spread of rumors and non-rumors. Our selected features classify rumors with high precision and recall in the range of 87% to 92%, that is higher than other states of the arts on rumor classification.
Streaming of user-generated video content (or UGC) has become an extremely popular Internet appli... more Streaming of user-generated video content (or UGC) has become an extremely popular Internet application. In this paper, we collect traces from two popular UGC services, YouTube 1 and Daum Movies 2 , and study their video characteristics. * Meeyoung is supported by Brain Korea 21 Project through the school of information technology in KAIST. This work was done while Meeyoung was an intern at Telefonica.
To increase reliability and robustness of mission-critical services in the event of network failu... more To increase reliability and robustness of mission-critical services in the event of network failures, it is often desirable and beneficial to take advantage of path di- versity provided by the network topology. One way of achiev- ing this inside a single Autonomous System (AS) is to use two paths between every Origin-Destination (OD) pair. One path is the default path
This paper presents a redundant multicast routing problem in multilayer networks that arises from... more This paper presents a redundant multicast routing problem in multilayer networks that arises from large-scale distribution of realtime multicast data (e.g., Internet TV, videocasting, online games, stock quotes). Since these multicast services commonly operate in multilayer networks, the communications paths need to be robust against a single router or link failure as well as multiple such failures due to shared risk link groups (SRLGs). The main challenge of this multicast is to ensure the service availability and reliability using a path protection scheme, which is to find a redundant path that is SRLG-disjoint (diverse) from each working path. The objective of this problem is, therefore, to find two redundant multicast trees, each from one of the two redundant sources to every destination, at a minimum total communication cost whereas two paths from the two sources to every destination are guaranteed to be SRLG-diverse (i.e., links in the same risk group are disjoint). In this paper, we present two new mathematical programming models, edge-based and path-based, for the redundant multicast routing problem with SRLG-diverse constraints. Because the number of paths in path-based model grows exponentially with the network size, it is impossible to enumerate all possible paths in real life networks. We develop three approaches (probabilistic, non-dominated and nearly non-dominated) to generate potentially good paths that may be included in the path-based model. This study is motivated by emerging applications of internet-protocol TV service, and we evaluate the proposed approaches using real life network topologies. Our empirical results suggest that both models perform very well, and the nearly non-dominated path approach outperforms all other path generation approaches.
There is a growing need for large-scale distribution of realtime multicast data such as Internet ... more There is a growing need for large-scale distribution of realtime multicast data such as Internet TV channels and scientific and financial data. Internet Service Providers (ISPs) face an urgent challenge in supporting these services; they need to design multicast routing paths that are reliable, cost-effective, and scalable. To meet the realtime constraint, the routing paths need to be robust against
In deep-submicron (DSM) technology, minimizing power consumption of a bus is one of the most impo... more In deep-submicron (DSM) technology, minimizing power consumption of a bus is one of the most important design objectives in embedded system-on-chip (SoC) design. In this paper, we address the problem of design space exploration of lowenergy software bus encoding in embedded SoC design. Traditionally, finding a bus encoding that leads to a minimum energy consumption of bus has been an important research issue, but relatively little attention has been paid to the cost of software encoding implementation. In embedded system design, the memory space for storing the encoding information is strictly limited. Consequently, exploring the bus encoding implementation alternatives under such constraint becomes very necessary and/or useful. In this paper, we propose a systematic design space exploration algorithm for low-power bus encoding which completely eliminates the crosstalk delay. From experiments on a set of benchmark designs, the proposed algorithm was shown to consume 48% less power consumption on average over existing techniques with relatively little memory overhead.
Abstract— The,distribution,of broadcast,TV across,large provider networks,has become,a highly top... more Abstract— The,distribution,of broadcast,TV across,large provider networks,has become,a highly topical subject as satellite distribution capacity exhausts and competitive pressures increase. In a typical IPTV architecture, broadcast TV is distributed from two sources (for redundancy),to multiple destinations. The aim of this paper,is to examine,how,IPTV can be reliably and,cost effectively supported,in wavelength,division multiplexed,(WDM) networks. WDM networks,have evolved to mesh,topologies and recently to support
We present a preliminary but groundbreaking study of the media landscape of Twitter. We use publi... more We present a preliminary but groundbreaking study of the media landscape of Twitter. We use public data on whom follows who to uncover common behaviour in media consumption, the relationship between various classes of media, and the diversity of media content which social links may bring. Our analysis shows that there is a non-negligible amount of indirect media exposure, either through friends who follow particular media sources, or via retweeted messages. We show that the indirect media exposure expands the political diversity of news to which users are exposed to a surprising extent, increasing the range by between 60-98%. These results are valuable because they have not been readily available to traditional media, and they can help predict how we will read news, and how publishers will interact with us in the future.
ABSTRACT Modern Massively Multiplayer Online Role-Playing Games (MMORPGs) provide lifelike virtua... more ABSTRACT Modern Massively Multiplayer Online Role-Playing Games (MMORPGs) provide lifelike virtual environments in which players can conduct a variety of activities including combat, trade, and chat with other players. While the game world and the available actions therein are inspired by their offline counterparts, the games' popularity and dedicated fan base are testaments to the allure of novel social interactions granted to people by allowing them an alternative life as a new character and persona. In this paper we investigate the phenomenon of "gender swapping," which refers to players choosing avatars of genders opposite to their natural ones. We report the behavioral patterns observed in players of Fairyland Online, a globally serviced MMORPG, during social interactions when playing as in-game avatars of their own real gender or gender-swapped. We also discuss the effect of gender role and self-image in virtual social situations and the potential of our study for improving MMORPG quality and detecting online identity frauds.
ABSTRACT How does one develop a new online community that is highly engaging to each user and pro... more ABSTRACT How does one develop a new online community that is highly engaging to each user and promotes social interaction? A number of websites offer friend-finding features that help users bootstrap social networks on the website by copying links from an established network like Facebook or Twitter. This paper quantifies the extent to which such social bootstrapping is effective in enhancing a social experience of the website. First, we develop a stylised analytical model that suggests that copying tends to produce a giant connected component (i.e., a connected community) quickly and preserves properties such as reciprocity and clustering, up to a linear multiplicative factor. Second, we use data from two websites, Pinterest and Last.fm, to empirically compare the subgraph of links copied from Facebook to links created natively. We find that the copied subgraph has a giant component, higher reciprocity and clustering, and confirm that the copied connections see higher social interactions. However, the need for copying diminishes as users become more active and influential. Such users tend to create links natively on the website, to users who are more similar to them than their Facebook friends. Our findings give new insights into understanding how bootstrapping from established social networks can help engage new users by enhancing social interactivity.
Online social networks have become a major communication platform, where people share their thoug... more Online social networks have become a major communication platform, where people share their thoughts and opinions about any topic real-time. The short text updates people post in these network contain emotions and moods, which when measured collectively can unveil the public mood at population level and have exciting implications for businesses, governments, and societies. Therefore, there is an urgent need for developing solid methods for accurately measuring moods from large-scale social media data. In this paper, we propose PANAS-t, which measures sentiments from short text updates in Twitter based on a well-established psychometric scale, PANAS (Positive and Negative Affect Schedule). We test the efficacy of PANAS-t over 10 real notable events drawn from 1.8 billion tweets and demonstrate that it can efficiently capture the expected sentiments of a wide variety of issues spanning tragedies, technology releases, political debates, and healthcare.
The problem of identifying rumors is of practical importance especially in online social networks... more The problem of identifying rumors is of practical importance especially in online social networks, since information can diffuse more rapidly and widely than the offline counterpart. In this paper, we identify characteristics of rumors by examining the following three aspects of diffusion: temporal, structural, and linguistic. For the temporal characteristics, we propose a new periodic time series model that considers daily and external shock cycles, where the model demonstrates that rumor likely have fluctuations over time. We also identify key structural and linguistic differences in the spread of rumors and non-rumors. Our selected features classify rumors with high precision and recall in the range of 87% to 92%, that is higher than other states of the arts on rumor classification.
Streaming of user-generated video content (or UGC) has become an extremely popular Internet appli... more Streaming of user-generated video content (or UGC) has become an extremely popular Internet application. In this paper, we collect traces from two popular UGC services, YouTube 1 and Daum Movies 2 , and study their video characteristics. * Meeyoung is supported by Brain Korea 21 Project through the school of information technology in KAIST. This work was done while Meeyoung was an intern at Telefonica.
To increase reliability and robustness of mission-critical services in the event of network failu... more To increase reliability and robustness of mission-critical services in the event of network failures, it is often desirable and beneficial to take advantage of path di- versity provided by the network topology. One way of achiev- ing this inside a single Autonomous System (AS) is to use two paths between every Origin-Destination (OD) pair. One path is the default path
This paper presents a redundant multicast routing problem in multilayer networks that arises from... more This paper presents a redundant multicast routing problem in multilayer networks that arises from large-scale distribution of realtime multicast data (e.g., Internet TV, videocasting, online games, stock quotes). Since these multicast services commonly operate in multilayer networks, the communications paths need to be robust against a single router or link failure as well as multiple such failures due to shared risk link groups (SRLGs). The main challenge of this multicast is to ensure the service availability and reliability using a path protection scheme, which is to find a redundant path that is SRLG-disjoint (diverse) from each working path. The objective of this problem is, therefore, to find two redundant multicast trees, each from one of the two redundant sources to every destination, at a minimum total communication cost whereas two paths from the two sources to every destination are guaranteed to be SRLG-diverse (i.e., links in the same risk group are disjoint). In this paper, we present two new mathematical programming models, edge-based and path-based, for the redundant multicast routing problem with SRLG-diverse constraints. Because the number of paths in path-based model grows exponentially with the network size, it is impossible to enumerate all possible paths in real life networks. We develop three approaches (probabilistic, non-dominated and nearly non-dominated) to generate potentially good paths that may be included in the path-based model. This study is motivated by emerging applications of internet-protocol TV service, and we evaluate the proposed approaches using real life network topologies. Our empirical results suggest that both models perform very well, and the nearly non-dominated path approach outperforms all other path generation approaches.
There is a growing need for large-scale distribution of realtime multicast data such as Internet ... more There is a growing need for large-scale distribution of realtime multicast data such as Internet TV channels and scientific and financial data. Internet Service Providers (ISPs) face an urgent challenge in supporting these services; they need to design multicast routing paths that are reliable, cost-effective, and scalable. To meet the realtime constraint, the routing paths need to be robust against
In deep-submicron (DSM) technology, minimizing power consumption of a bus is one of the most impo... more In deep-submicron (DSM) technology, minimizing power consumption of a bus is one of the most important design objectives in embedded system-on-chip (SoC) design. In this paper, we address the problem of design space exploration of lowenergy software bus encoding in embedded SoC design. Traditionally, finding a bus encoding that leads to a minimum energy consumption of bus has been an important research issue, but relatively little attention has been paid to the cost of software encoding implementation. In embedded system design, the memory space for storing the encoding information is strictly limited. Consequently, exploring the bus encoding implementation alternatives under such constraint becomes very necessary and/or useful. In this paper, we propose a systematic design space exploration algorithm for low-power bus encoding which completely eliminates the crosstalk delay. From experiments on a set of benchmark designs, the proposed algorithm was shown to consume 48% less power consumption on average over existing techniques with relatively little memory overhead.
Abstract— The,distribution,of broadcast,TV across,large provider networks,has become,a highly top... more Abstract— The,distribution,of broadcast,TV across,large provider networks,has become,a highly topical subject as satellite distribution capacity exhausts and competitive pressures increase. In a typical IPTV architecture, broadcast TV is distributed from two sources (for redundancy),to multiple destinations. The aim of this paper,is to examine,how,IPTV can be reliably and,cost effectively supported,in wavelength,division multiplexed,(WDM) networks. WDM networks,have evolved to mesh,topologies and recently to support
We present a preliminary but groundbreaking study of the media landscape of Twitter. We use publi... more We present a preliminary but groundbreaking study of the media landscape of Twitter. We use public data on whom follows who to uncover common behaviour in media consumption, the relationship between various classes of media, and the diversity of media content which social links may bring. Our analysis shows that there is a non-negligible amount of indirect media exposure, either through friends who follow particular media sources, or via retweeted messages. We show that the indirect media exposure expands the political diversity of news to which users are exposed to a surprising extent, increasing the range by between 60-98%. These results are valuable because they have not been readily available to traditional media, and they can help predict how we will read news, and how publishers will interact with us in the future.
ABSTRACT Modern Massively Multiplayer Online Role-Playing Games (MMORPGs) provide lifelike virtua... more ABSTRACT Modern Massively Multiplayer Online Role-Playing Games (MMORPGs) provide lifelike virtual environments in which players can conduct a variety of activities including combat, trade, and chat with other players. While the game world and the available actions therein are inspired by their offline counterparts, the games' popularity and dedicated fan base are testaments to the allure of novel social interactions granted to people by allowing them an alternative life as a new character and persona. In this paper we investigate the phenomenon of "gender swapping," which refers to players choosing avatars of genders opposite to their natural ones. We report the behavioral patterns observed in players of Fairyland Online, a globally serviced MMORPG, during social interactions when playing as in-game avatars of their own real gender or gender-swapped. We also discuss the effect of gender role and self-image in virtual social situations and the potential of our study for improving MMORPG quality and detecting online identity frauds.
ABSTRACT How does one develop a new online community that is highly engaging to each user and pro... more ABSTRACT How does one develop a new online community that is highly engaging to each user and promotes social interaction? A number of websites offer friend-finding features that help users bootstrap social networks on the website by copying links from an established network like Facebook or Twitter. This paper quantifies the extent to which such social bootstrapping is effective in enhancing a social experience of the website. First, we develop a stylised analytical model that suggests that copying tends to produce a giant connected component (i.e., a connected community) quickly and preserves properties such as reciprocity and clustering, up to a linear multiplicative factor. Second, we use data from two websites, Pinterest and Last.fm, to empirically compare the subgraph of links copied from Facebook to links created natively. We find that the copied subgraph has a giant component, higher reciprocity and clustering, and confirm that the copied connections see higher social interactions. However, the need for copying diminishes as users become more active and influential. Such users tend to create links natively on the website, to users who are more similar to them than their Facebook friends. Our findings give new insights into understanding how bootstrapping from established social networks can help engage new users by enhancing social interactivity.
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