Yongsung Kim

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In this paper we present a hybrid model for real-time query processing over data stream collected by mobile air quality sensors. First, we introduce a novel indexing scheme for representing air quality and use it for generating and evaluating a static model over a yearly dataset. Then, this model is combined with a dynamic nearest-neighbor approach for(More)
The 90-9-1 rule is widely applied to online communities to describe a phenomenon of participation inequality [4]. The 90-9-1 rule states that 90% of users are "lurkers" who do not contribute, 9% are those who contribute from time to time, and only 1% of participants are highly active in the community and make most contributions. The question is: how can we(More)
In location-based social Q&A, the questions related to a local community (e.g. local services and places) are typically answered by local residents (i.e. who have the local knowledge). In this work, we wanted to deepen our understanding of the localness of knowledge sharing through investigating the topical and typological patterns related to the(More)
We present <i>Mobile Observatory</i>, a mobile air quality monitoring application that provides evaluation of air quality of the city of Zurich, Switzerland. As <i>Mobile Observatory</i> utilizes air quality data gathered by sensors mounted on around 10 trams in Zurich, it is able to provide neighborhood-level air quality information within the city. In(More)
Citizen science and communitysensing applications allow everyday citizens to collect data about the physical world to benefit science and society. Yet despite successes, current approaches are still limited by the number of domain-interested volunteers who are willing and able to contribute useful data. In this paper we introduce <i>habitsourcing</i>, an(More)
We present CrowdFound, a mobile crowdsourcing system to find lost items. CrowdFound allows users to input lost item descriptions on a map and then sends notifications to users passing near tagged areas. To assess the system's efficacy, we conducted interviews and user testing on CrowdFound. Our results show that users were able to find lost items when using(More)
This paper introduces the idea of sending timely notifications to potential helpers to complete small tasks on-the-go with minimal effort to them and maximal benefit to the system. We present two on-the-go crowdsourcing systems: Libero for package delivery, and CrowdFound for finding lost items. To encourage contributions, we introduce notification(More)
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