이의진 교수

There has been recent interests in studying the "goal" behind a user's Web query, so that this goal can be used to improve the quality of a search engine's results. Previous studies have mainly focused on using manual query-log investigation to identify Web query goals. In this paper we study whether and how we can automate this goal-identification process. We first present our results from a human subject study that strongly indicate the feasibility of automatic query-goal identification. We th

Vehicular sensor networks are emerging as a new network paradigm of primary relevance, especially for proactively gathering monitoring information in urban environments. Vehicles typically have no strict constraints on processing power and storage capabilities. They can sense events (e.g., imaging from streets), process sensed data (e.g., recognizing license plates), and route messages to other vehicles (e.g., diffusing relevant notification to drivers or police agents). In this novel and challe

A SEA Swarm (Sensor Equipped Aquatic Swarm) is a sensor "cloud" that drifts with water currents and enables 4D (space and time) monitoring of local underwater events such as contaminants, marine life and intruders. The swarm is escorted at the surface by drifting sonobuoys that collect the data from underwater sensors via acoustic modems and report it in real-time via radio to a monitoring center. The goal of this study is to design an efficient anycast routing algorithm for reliable underwater

Mobile peer-to-peer systems have recently got in the lime-light of the research community that is striving to build efficient and effective mobile content addressable networks. Along this line of research, we propose a network coding based file swarming protocol targeting vehicular ad hoc net-works (VANET). We argue that file swarming protocols in VANET should deal with typical mobile network issues such as dynamic topology and intermittent connectivity as well as various other issues that have

Recent advances in vehicular communications make it possible to realize vehicular sensor networks, i.e., collaborative environments where mobile vehicles that are equipped with sensors of different nature (from toxic detectors to still/video cameras) interwork to implement monitoring applications. In particular, there is an increasing interest in proactive urban monitoring, where vehicles continuously sense events from urban streets, autonomously process sensed data (e.g., recognizing license pl

The negative aspects of smartphone overuse on young adults, such as sleep deprivation and attention deficits, are being increasingly recognized recently. This emerging issue motivated us to analyze the usage patterns related to smartphone overuse. We investigate smartphone usage for 95 college students using surveys, logged data, and interviews. We first divide the participants into risk and non-risk groups based on self-reported rating scale for smartphone overuse. We then analyze the usage dat

Our energy efficiency analysis of various content dissemination strategies reveals that a change in network architecture from host-oriented to content-centric networking (CCN) can open new possibilities for energy-efficient content dissemination. In this paper, we consider energy-efficient CCN architecture and validate its energy efficiency via trace-based simulations. The results confirm that CCN is more energy efficient than conventional CDNs and P2P networks, even under incremental deployment

In this study, we introduce the concept of a virtual ¿flea market¿ over a vehicular ad hoc network (VANET) called FleaNet. FleaNet customers express their demands/offers to buy/sell items via radio queries. These queries are opportunistically disseminated, exploiting the mobility of other customers, until a matching customer/vendor is found. We identify the key performance metrics, namely, query resolution latency, scalability, mobility, and churning, and evaluate their impact on performance usi

A major role of today's Internet is to provide efficient content dissemination among users, such as distributing multimedia content and sharing user generated data. To meet the ever increasing demands, the Internet has been rapidly growing, and it now includes a web of tens of millions of networked devices ranging from content servers to core and edge routers to home gateways. Due to the sheer numbers, however, it is reported that these devices, such as those used for content delivery, consume a

Mobile wireless networks with intermittent connectivity, often called Delay/Disruption Tolerant Networks (DTNs), have recently received a lot of attention because of their applicability in various applications, including multicasting. To overcome intermittent connectivity, DTN routing protocols utilize mobility-assist routing by letting the nodes carry and forward the data. In this paper, we study the scalability of DTN multicast routing. As Gupta and Kumar showed that unicast routing is not sca

In this paper we study the use of vehicles as sensors in a "vehicular sensor network" a new network paradigm that is critical for gathering valuable information in urban environments. In a vehicular sensor network, each vehicle is responsible for sensing one or more events, routing messages to other vehicles or infostations and processing sensed data. There are several critical differences between a vehicular sensor network and a "traditional" wireless sensor network, namely: 1) the vehicular ne

<b>Introduction:</b> With the COVID-19 outbreak, South Korea has been making contact trace data public to help people self-check if they have been in contact with a person infected with the coronavirus. Despite its benefits in suppressing the spread of the virus, publicizing contact trace data raises concerns about individuals' privacy. In view of this tug-of-war between one's privacy and public safety, this work aims to deepen the understanding of privacy risks of contact trace data disclosure