Data+Science+Lab
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‘Urban Green Space Affects Citizens’ Happiness’
Study finds the relationship between green space, the economy, and happiness
A recent study revealed that as a city becomes more economically developed, its citizens’ happiness becomes more directly related to the area of urban green space.
A joint research project by Professor Meeyoung Cha of the School of Computing and her collaborators studied the relationship between green space and citizen happiness by analyzing big data from satellite images of 60 different countries.
Urban green space, including parks, gardens, and riversides not only provides aesthetic pleasure, but also positively affects our health by promoting physical activity and social interactions. Most of the previous research attempting to verify the correlation between urban green space and citizen happiness was based on few developed countries. Therefore, it was difficult to identify whether the positive effects of green space are global, or merely phenomena that depended on the economic state of the country. There have also been limitations in data collection, as it is difficult to visit each location or carry out investigations on a large scale based on aerial photographs.
The research team used data collected by Sentinel-2, a high-resolution satellite operated by the European Space Agency (ESA) to investigate 90 green spaces from 60 different countries around the world. The subjects of analysis were cities with the highest population densities (cities that contain at least 10% of the national population), and the images were obtained during the summer of each region for clarity. Images from the northern hemisphere were obtained between June and September of 2018, and those from the southern hemisphere were obtained between December of 2017 and February of 2018.
The areas of urban green space were then quantified and crossed with data from the World Happiness Report and GDP by country reported by the United Nations in 2018. Using these data, the relationships between green space, the economy, and citizen happiness were analyzed.
The results showed that in all cities, citizen happiness was positively correlated with the area of urban green space regardless of the country’s economic state. However, out of the 60 countries studied, the happiness index of the bottom 30 by GDP showed a stronger correlation with economic growth. In countries whose gross national income (GDP per capita) was higher than 38,000 USD, the area of green space acted as a more important factor affecting happiness than economic growth. Data from Seoul was analyzed to represent South Korea, and showed an increased happiness index with increased green areas compared to the past.
The authors point out their work has several policy-level implications. First, public green space should be made accessible to urban dwellers to enhance social support. If public safety in urban parks is not guaranteed, its positive role in social support and happiness may diminish. Also, the meaning of public safety may change; for example, ensuring biological safety will be a priority in keeping urban parks accessible during the COVID-19 pandemic.
Second, urban planning for public green space is needed for both developed and developing countries. As it is challenging or nearly impossible to secure land for green space after the area is developed, urban planning for parks and green space should be considered in developing economies where new cities and suburban areas are rapidly expanding.
Third, recent climate changes can present substantial difficulty in sustaining urban green space. Extreme events such as wildfires, floods, droughts, and cold waves could endanger urban forests while global warming could conversely accelerate tree growth in cities due to the urban heat island effect. Thus, more attention must be paid to predict climate changes and discovering their impact on the maintenance of urban green space.
“There has recently been an increase in the number of studies using big data from satellite images to solve social conundrums,” said Professor Cha. “The tool developed for this investigation can also be used to quantify the area of aquatic environments like lakes and the seaside, and it will now be possible to analyze the relationship between citizen happiness and aquatic environments in future studies,” she added.
Professor Woo Sung Jung from POSTECH and Professor Donghee Wohn from the New Jersey Institute of Technology also joined this research. It was reported in the online issue of EPJ Data Science on May 30.
-PublicationOh-Hyun Kwon, Inho Hong, Jeasurk Yang, Donghee Y. Wohn, Woo-Sung Jung, andMeeyoung Cha, 2021. Urban green space and happiness in developed countries. EPJ Data Science. DOI: https://doi.org/10.1140/epjds/s13688-021-00278-7
-ProfileProfessor Meeyoung ChaData Science Labhttps://ds.ibs.re.kr/
School of Computing
KAIST
2021.06.21 View 9280 -
Research on the Million Follower Fallacy Receives the Test of Time Award
Professor Meeyoung Cha’s research investigating the correlation between the number of followers on social media and its influence was re-highlighted after 10 years of publication of the paper.
Saying that her research is still as relevant today as the day it was published 10 years ago, the Association for the Advancement of Artificial Intelligence (AAAI) presented Professor Cha from the School of Computing with the Test of Time Award during the 14th International Conference on Web and Social Media (ICWSM) held online June 8 through 11.
In her 2010 paper titled ‘Measuring User Influence in Twitter: The Million Follower Fallacy,’ Professor Cha proved that number of followers does not match the influential power. She investigated the data including 54,981,152 user accounts, 1,963,263,821 social links, and 1,755,925,520 Tweets, collected with 50 servers.
The research compares and illustrates the limitations of various methods used to measure the influence a user has on a social networking platform. These results provided new insights and interpretations to the influencer selection algorithm used to maximize the advertizing impact on big social networking platforms.
The research also looked at how long an influential user was active for, and whether the user could freely cross the borders between fields and be influential on different topics as well. By analyzing cases of who becomes an influencer when new events occur, it was shown that a person could quickly become an influencer using several key tactics, unlike what was previously claimed by the ‘accidental influential theory’.
Professor Cha explained, “At the time, data from social networking platforms did not receive much attention in computer science, but I remember those all-nighters I pulled to work on this project, fascinated by the fact that internet data could be used to solve difficult social science problems. I feel so grateful that my research has been endeared for such a long time.”
Professor Cha received both her undergraduate and graduate degrees from KAIST, and conducted this research during her postdoctoral course at the Max Planck Institute in Germany. She now also serves as a chief investigator of a data science group at the Institute for Basic Science (IBS).
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2020.06.22 View 6220 -
A Global Campaign of ‘Facts before Rumors’ on COVID-19 Launched
- A KAIST data scientist group responds to facts and rumors on COVID-19 for global awareness of the pandemic. -
Like the novel coronavirus, rumors have no borders. The world is fighting to contain the pandemic, but we also have to deal with the appalling spread of an infodemic that is as contagious as the virus. This infodemic, a pandemic of false information, is bringing chaos and extreme fear to the general public.
Professor Meeyoung Cha’s group at the School of Computing started a global campaign called ‘Facts before Rumors,’ to prevent the spread of false information from crossing borders. She explained, “We saw many rumors that had already been fact-checked long before in China and South Korea now begin to circulate in other countries, sometimes leading to detrimental results. We launched an official campaign, Facts before Rumors, to deliver COVID-19-related facts to countries where the number of cases is now increasing.” She released the first set of facts on March 26 via her Twitter account @nekozzang.
Professor Cha, a data scientist who has focused on detecting global fake news, is now part of the COVID-19 AI Task Force at the Global Strategy Institute at KAIST. She is also leading the Data Science Group at the Institute for Basic Science (IBS) as Chief Investigator.
Her research group worked in collaboration with the College of Nursing at Ewha Woman’s University to identify 15 claims about COVID-19 that circulated on social networks (SNS) and among the general public. The team fact-checked these claims based on information from the WHO and CDCs of Korea and the US. The research group is now working on translating the list of claims into Portuguese, Spanish, Persian, Chinese, Amharic, Hindi, and Vietnamese. Delivering facts before rumors, the team says, will help contain the disease and prevent any harm caused by misinformation.
The pandemic, which spread in China and South Korea before arriving in Europe and the US, is now moving into South America, Africa, and Southeast Asia. “We would like to play a part in preventing the further spread of the disease with the provision of only scientifically vetted, truthful facts,” said the team.
For this campaign, Professor Cha’s team investigated more than 200 rumored claims on COVID-19 in China during the early days of the pandemic. These claims spread in different levels: while some were only relevant locally or in larger regions of China, others propagated in Asia and are now spreading to countries that are currently most affected by the disease.
For example, the false claim which publicized that ‘Fireworks can help tame the virus in the air’ only spread in China. Other claims such as ‘Eating garlic helps people overcome the disease’ or ‘Gargling with salt water prevents the contraction of the disease,’ spread around the world even after being proved groundless.
The team noted, however, that the times at which these claims propagate are different from one country to another. “This opens up an opportunity to debunk rumors in some countries, even before they start to emerge,” said Professor Cha.
Kun-Woo Kim, a master’s candidate in the Department of Industrial Design who joined this campaign and designed the Facts before Rumors chart also expressed his hope that this campaign will help reduce the number of victims. He added, “I am very grateful to our scientists who quickly responded to the Fact Check in these challenging times.”
2020.03.27 View 10716 -
COVID-19 Map Shows How the Global Pandemic Moves
- A School of Computing team facilitated the data from COVID-19 to show the global spread of the virus. -
The COVID-19 map made by KAIST data scientists shows where and how the virus is spreading from China, reportedly the epicenter of the disease.
Professor Meeyoung Cha from the School of Computing and her group facilitated data based on the number of confirmed cases from January 22 to March 22 to analyze the trends of this global epidemic. The statistics include the number of confirmed cases, recoveries, and deaths across major continents based on the number of confirmed case data during that period.
The moving dot on the map strikingly shows how the confirmed cases are moving across the globe. According to their statistics, the centroid of the disease starts from near Wuhan in China and moved to Korea, then through the European region via Italy and Iran.
The data is collected by a graduate student from the School of Computing, Geng Sun, who started the process during the time he was quarantined since coming back from his home in China. An undergraduate colleague of Geng's, Gabriel Camilo Lima who made the map, is now working remotely from his home in Brazil since all undergraduate students were required to move out of the dormitory last week. The university closed all undergraduate housing and advised the undergraduate students to go back home in a preventive measure to stop the virus from spreading across the campus.
Gabriel said he calculated the centroid of all confirmed cases up to a given day. He explained, “I weighed each coordinate by the number of cases in that region and country and calculated an approximate center of gravity.”
“The Earth is round, so the shortest path from Asia to Europe is often through Russia. In early March, the center of gravity of new cases was moving from Asia to Europe. Therefore, the centroid is moving to the west and goes through Russia, even though Russia has not reported many cases,” he added.
Professor Cha, who is also responsible for the Data Science Group at the Institute for Basic Science (IBS) as the Chief Investigator, said their group will continue to update the map using public data at https://ds.ibs.re.kr/index.php/covid-19/.
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2020.03.27 View 10316 -
Businessweek: How Twitter Could Unleash World Peace, April 11, 2011
A KAIST graduate scholar, Meeyoung Cha, conducted a joint study with international researchers and released a paper on the aspect of twitter as an emerging cyber arena for political and social debates and discussions. An article on the paper from Businessweek follows:
Businessweek
April 11, 2011, 9:08PM EST text size: TT
How Twitter Could Unleash World Peace
Researchers from Britain, Korea, and Germany have determined that the amount of fresh information you get on Twitter is less a matter of what you follow than whom—and who follows you
By Bobbie Johnson
On certain days, Twitter can feel like the world"s biggest, fastest echo chamber. Since we tend to follow people who are similar to us, we often see our own views reflected back—meaning a gloomy cloud of irritation can rapidly swirl into a cyclone of outrage as we hear from other people who feel as we do. A group of computer scientists have discovered that the opposite may also be true. Can Twitter be part of the solution, not merely part of the problem?
In a study to be presented at a conference in July, a team of researchers from the U.K."s University of Cambridge, Korea"s Graduate School of cultural Technology-KAIST, and Germany"s Max Planck Institute for Software Systems show how Twitter can provide users greater access to more varied political viewpoints and media sources than they might otherwise get.
The paper, called "The Media Landscape in Twitter(http://www.cl.cam.ac.uk/~jac22/out/twitter-diverse.pdf)," explains how the team made surprising discoveries when they looked into the site"s usage patterns. First they looked at who follows whom and discovered that Twitter is a highly politicized space. Then they examined patterns of tweeting and retweeting to try to understand how people receive information on Twitter—and what they might see. Their conclusion: Although Twitter is a pretty partisan space, it can offer unprecedented opportunities to break down the barriers that plague local, national, and international politics.
How? Through retweets and interaction—what the authors call "indirect media exposure." As they put it, this "expands the political diversity of news to which users are exposed to a surprising extent, increasing the range by between 60 percent and 98 percent. 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."
If you"re interested in the way Twitter works, I recommend reading the paper, which isn"t very long. Meanwhile, let"s boil it down to a few key pieces of data and see what lessons they can teach.
Most Twitter users are political. Just over half (50.8 percent) of all Twitter users studied showed a distinct political bias in the media outlets and individuals they followed. Most of those lean to the left of the political spectrum, accounting for 62 percent of users who demonstrated some bias. Thirty-seven percent were doggedly centrist. Just 1 percent of Twitter users who showed a political preference were right-wing.
Here are a couple of caveats about reading too much into the sharp divide the authors found. Given that Twitter"s user base is younger and more metropolitan than the societal norm, it"s not surprising that it"s weighted to the left. It"s worth noting that this study was undertaken more than a year ago; since then, Twitter has grown dramatically, while global politics have largely skewed back toward the right. Twitter"s user base today might reflect a more-balanced political picture. Either way, there"s a big split.
Twitter has secondary and tertiary benefits. Most organizations comprehend Twitter in simple terms: More followers means more exposure. But the study shows that it"s not just about those you follow, but those your followers follow—essentially the people in your extended network. The network offers a number of routes for information from fresh sources to get to you. According to the study, some 80 percent of users choose to follow at least 10 media sources, but they are exposed to between 6 and 10 times as many media sources through their friends.
People outweigh brands. Many of the biggest Twitter accounts are big media brands such as CNN (TWX) and Time, but the study suggests that Twitter"s active users tend to prefer individuals over outlets. So while the average follower of @NYTimes (NYT) has six followers apiece, individual journalists have followers who boast a median following count of around 100. That gives individual journalists—who are, the study says, more likely to link to a multiplicity of sources—a much wider, more influential network of connections.
The inference is that the personal touch of a journalist is more important than the lofty, impersonal tone of publications that largely act as promotion channels for their content. It"s a discovery that reminded me of Twitter"s recent blog post on the science of the hashtag, which found that hashtags explode in usage when they are picked up by individuals with the most dedicated—not necessarily the largest—followings.
Active users access a wider range of views. The researchers say that indirect exposure expands political diversity by a "significant amount," despite other studies showing a tendency for social networks to do the opposite. "Other studies have found a stronger tendency of homophily; blogs of different political views rarely linked to each other," they point out. "One possible reason is that a Twitter network encompasses several different relationships—from shared interest, to familial ties, friends, and acquaintances—so political similarity doesn"t necessarily exist in all such ties."
This is not to say that Twitter"s creators should be preparing a Nobel Prize-winning speech. Far from it: The influence of its diversity is unknown. It could be that many people who see messages they disagree with simply change their behavior to screen out such material in future. But it shows that there is a potential to do something positive at Twitter. It"s clear there"s much work to be done. The researchers say they want to investigate a number of areas they"ve uncovered, having provided important insights at a time when politics seem more fractious and divided than ever.
2011.04.12 View 10749 -
Interesting research results were published on the use of Twitter.
The number of “followers” on your Twitter account does not necessarily mean that “Your opinions matter much” to other people.
A KAIST graduate researcher, Mi-Young Cha, joined an interesting project that studies the influence of a popular social media, Twitter. Most of Twitter users today consider the number of followers as a measurement of their influence on the social sphere. According to the research paper, however, this connection does not seem to standing together. For details, please click the link below for an article published by the New York Times.
Dr. Cha received all of her post secondary education degrees in Computer Science, including her Ph.D. in 2008, from KAIST. Since 2008 till now, she has been a post doctoral researcher at Max Planck Institute for Software Systems (MPI-SWS) based in Germany.
[New York Times Article, March 19, 2010]
http://www.nytimes.com/external/readwriteweb/2010/03/19/19readwriteweb-the-million-follower-fallacy-audience-size-d-3203.html
2010.04.05 View 12192