Juong-Sik Lee

TruCentive: A game-theoretic incentive platform for trustworthy mobile crowdsourcing parking services

The shortage of parking in crowded urban areas causes severe societal problems such as traffic congestion, environmental pollution, and many others. Recently, crowdsourced parking, where smartphone users are exploited to collect realtime parking availability information, has attracted significant attention. However, existing crowdsourced parking information systems suffer from low user participation rate and data quality due to the lack of carefully designed incentive schemes. In this paper, we address the incentive problem of trustworthy crowdsourced parking information systems by presenting an incentive platform named TruCentive, where high utility parking data can be obtained from unreliable crowds of mobile users. Our contribution is three-fold. First, we provide hierarchical incentives to stimulate the participation of mobile users for contributing parking information. Second, by introducing utility-related incentives, our platform encourages participants to contribute high utility data and thereby enhances the quality of collected data. Third, our active confirmation scheme validates the parking information utility by game-theoretically formulated incentive protocols. The active confirming not only validates the utility of contributed data but re-sells the high utility data as well. Our evaluation through user study on Amazon Mechanical Turk and simulation study demonstrate the feasibility and stability of TruCentive incentive platform.

A novel auction mechanism for selling time-sensitive e-services

Many e-services are time-sensitive as the users request them for a specific time period. Such services need to be repeatedly offered to keep them constantly utilized. This paper studies winner selection strategies in a recurring auction for such time-sensitive e-services. We observe that because of uneven wealth distribution, the least wealthy bidders tend to drop out of recurring auction as they persistently loose. The bidders dropping out of an auction decrease competition and can cause a collapse of winning prices. We propose and evaluate a novel auction mechanism that enables bidder drop control. Compared to traditional auction mechanisms, ours increases revenue of the e-service provider and decreases loss of fairness of the e-service allocation.

Auctions as a Dynamic Pricing Mechanism for E-Services

Increasing role of services in developed economies around the world combined with ubiquitous presence of computer networks and information technologies result in rapid growth of e-services. Markets for e-services often require flexible pricing to be efficient and therefore frequently use auctions to satisfy this requirement. However, auctions in e-service markets are recurring since typically e-services are offered repeatedly, each time for a specific time interval. Additionally, all e-services offered in an auction round must be sold to avoid resource waste. Finally, enough bidders must be willing to participate in future auction rounds to prevent a collapse of market prices. Because of these requirements, previously designed auctions cannot work efficiently in e-service markets. In this chapter, we introduce and evaluate a novel auction, called Optimal Recurring Auction (ORA), for e-services markets. We present also simulation results that show that, unlike the traditional auctions, ORA stabilizes the market prices and maximizes the auctioneers revenue in e-service markets.

A Participation Incentive Market Mechanism for Allocating Heterogeneous Network Services

This paper studies an auction based allocation of network resources for short-term contracts for heterogeneous network services. The combinatorial winner selection yields the optimal resources allocation in a single-round auction for heterogeneous resources. However, the recurring nature of auction for network services causes least wealthy bidders to exit the auction as they persistently lose under the traditional combinatorial winner selection that focuses only on revenue maximization. Such exits decrease price competition and may cause a collapse of the selling prices and revenues of network service providers. We introduce and evaluate a novel auction based network resource allocation and pricing mechanism for heterogeneous network services. The proposed mechanism prevents collapse of the selling prices and the auctioneers revenues, stabilizes auction market, and enhances social welfare by allowing larger subset of users to become occasional winners of auction rounds than the traditional combinatorial winner selection does.

Stabilizing markets via a novel auction based pricing mechanism for short-term contracts for network services

This paper studies pricing mechanisms for short-term contracts for network services in a recurring auction with sealed bids. We propose and evaluate a novel winner selection policy in such an auction. The new approach was motivated by an observation that in a recurring auction enough customers must be willing to participate in future auction rounds to prevent collapse of prices. Using simulations, we compare the proposed mechanism with traditional ones. The results demonstrate that the new method (i) increases revenues of the network service provider, (ii) minimizes loss of fairness, and (iii) enlarges the active customer base of a recurring auction.

Mobile phone-to-phone personal context sharing

Sharing personal context information using mobile phone is receiving considerable attentions in ubiquitous computing applications. The most common architecture for sharing personal context information via mobile phone uses centralized server. Such server-based architecture, however, cannot avoid waste of mobile phones limited resources for sharing personal context information. Additionally, dynamic privacy control of the shared context information according to users various situations is very difficult in the server-based architecture. The increased computation power of mobile phone enables us to create system architecture that can share personal context information between two mobile phones directly. In this paper, we describe design of system architecture for lightweight interactive mobile phone-to-phone personal context sharing system that uses SMS (Short Message Services) as a basic communication method, and introduce application prototypes that are developed based on the proposed architecture. Compared to centralized server-based architecture, the proposed one can minimize waste of limited mobile phone resources and maximizes dynamic privacy control in sharing personal context information.

Personal Relationship Management via Mobile Phone

Efficiently maintaining and managing personal relationships have become imperative in our personal and professional lives. In this paper we describe the design of a mobile Personal Relationship Manager (PRM), a prototype implementation on Nokia S60 smartphones, and results from initial user studies. The PRM system automatically extracts and manages contacts and their network from users various communication activities, and provides various functions for managing personal communications efficiently. Our contributions are to make it easy to enable the users to manage personal relationships and communications, and the user studies that validate the design of our prototype.

Unveiling locations in geo-spatial documents

Resolving geo-identities of addresses in emerging economies where users rely primarily on short messaging as the means of querying, poses several daunting challenges: lack of proper addressing schemes, non-availability of cartographic information and non-standardized nomenclature of geo-spatial entities such as streets and avenues, to name a few. In this work, we propose a simple and elegant approach to solve this problem for emerging economies. By treating address texts as short documents and exploiting latent proximity information contained in them --- for example, landmark like references, similarity of address texts etc --- we transform the problem of resolving geo-identity to a search problem on short annotated geo-spatial documents, collected through extensive survey of six cities in India. Our solution spans all the phases of building a geo-identity resolution system, even though our emphasis is on the collection and organization of the corpus to facilitate a search engine backend for the task. Through experimentation based on a representative test set collected from the real world, we demonstrate how this approach achieves over 94% accuracy in resolution and an order of magnitude reduction in system state (memory) with nearly zero false-negatives - a significant improvement over the state of the art in emerging markets.