2015 Informs Annual Meeting

MA27

INFORMS Philadelphia – 2015

3 - Randomized Experiment(s) Evaluating the Drivers of User Content Generation Gordon Burtch, Assistant Professor, University of Minnesota, 321 19th Ave. S., Minneapolis, MN, 55455, United States of America, gburtch@umn.edu, Kevin Hong, Ravi Bapna, Vladas Griskevicius UGC under-provision is a persistent problem in many online communities. We undertake a set of randomized experiments aimed at understanding the drivers of increased UGC production, in terms of both quantity and quality. We consider i) the role of peer feedback on past content (stated approval vs. download), and ii) incentives to contribution (social vs. monetary). MA26 26-Room 403, Marriott 2015 INFORMS Special Session for JIPE and IJOR Cluster: Globalization and International Activities Invited Session Chair: Kuo-Hao Chang, National Tsing Hua University, Hsinchu, Taiwan, China, chang@mx.nthu.edu.tw 1 - An Activity-Driven Optimization Model for Smart Space Kuo-Hao Chang, National Tsing Hua University, Hsinchu, Taiwan, China, chang@mx.nthu.edu.tw In this paper, we propose an activity-driven optimization model, followed by the development of a solution method, to enable the optimal and automatic control of environmental conditions, including humidity and temperature, so as to provide people with the most comfortable environment but with the least energy consumption. A computational study based on instances of realistic size is conducted at the end to show the viability of the research. 2 - Optimal Arc Restoration Schedules with Resource Constraints for Recovering Nodes in a Network of Damaged Arcs I-Lin Wang, Professor, Department of Industrial and Information Management, National Cheng Kung University, Tainan, Taiwan, China, ilinwang@mail.ncku.edu.tw Consider a network containing some damaged arcs with estimated restoration time and resource. In order to access all nodes in minimum time, we aim to find optimal arc restoration schedules that determine the timing and resources required for restoring some damaged arcs. We will show that special cases of this problem can be converted to minimum spanning tree, shortest path, and NP-hard parallel machine scheduling problems. Finally, proposed IP formulations and solution methods will be discussed. 3 - The Coopetition Game in International Liner Shipping Dung-Ying Lin, Associate Professor, Department of Transportation and Communication Management Science, National Cheng Kung University, Tainan 70101, Taiwan, China, dylin@mail.ncku.edu.tw In maritime freight transportation, carriers build a collaborative relationship with other carriers while competing with each other to optimize their own profits. In this scenario, a game of coopetition is formed. We formulate a nonlinear mixed- integer problem to determine the optimal levels of coopetition for a single company and embed the resulting problem into a general game theoretic framework. A diagonalization algorithm that incorporates an ascent direction search technique is developed to effectively evaluate the game. The numerical results show that carriers choose similar coopetition levels to maximize their profits, and the coopetition game can reach equilibrium under general conditions. MA27 27-Room 404, Marriott Theory and Applications of the Analytic Network Process Sponsor: Multiple Criteria Decision Making Sponsored Session Chair: Orrin Cooper, University of Memphis, 332 Fogelman, Memphis, TN, United States of America, olcooper@memphis.edu 1 - Coherence within the ANP Supermatrix Orrin Cooper, University of Memphis, 332 Fogelman, Memphis, TN, United States of America, olcooper@memphis.edu, Idil Yavuz In an ANP network there is both the ability and the need to check for additional levels of consistency and coherence. A Supermatrix with priority vectors that were obtained from either perfect or nearly perfect consistent pairwise comparison can generate suboptimal decisions. Simulations demonstrate the frequency of these events in general ANP networks. A form of cross validation within the Supermatrix called linking validation and a Linking Coherency Index (LCI) is developed and demonstrated.

many have fleeting interests and only generate noise that skew analyses. Thus we propose an automated and scalable approach to identify top hacker participants in big online communities. Specifically, we utilize discrete-time duration modeling with recurrent events for extracting top participating hackers among large hacker IRC communities. 2 - Semi-supervised Learning for Structured Regression on Partially Observed Attributed Graphs Zoran Obradovic, Laura H. Carnell Professor Of Data Analytics; Director, Center For Data Analytics And Biomedical Informatics; Professor, Computer And Information Sciences Department; Professor, Statistics Department, Temple University, 1925 N. 12th St., 386 SERC, Philadelphia, PA, 19122, United States of America, zoran.obradovic@temple.edu, Jelena Stojanovic, Djordje Gligorijevic, Milos Jovanovic We propose a structured regression model for temporal applications where a large fraction of observations is missing. The benefits are demonstrated on precipitation prediction and on hundreds of evolving graphs with up to 80% labels missing under various mechanisms. The proposed method and result were published at SDM 2015 conference proceedings. 3 - From Spot Market to Customized Contract: Role of Reputation on Market Choice of Crowdsourcing Venders Xiao Han, Shanghai Jiaotong University, 1954 Huashan Rd, Shanghai, China, hanxiao@sjtu.edu.cn, Pei-yu Chen, Bin Gu, Pengzhu Zhang Based on a unique dataset obtained from a large online crowdsourcing platform with different markets in China, we examine the effect of reputation on vendors’ winning chance and revenues as well as their market choices over time. Our results show that as venders become more experienced and establish more successful relationships with buyers, they will move from spot market to customized contract market, at the same time, they will win more and earn more. 4 - The Heterogeneity of Online Searching and Its Impact on Stock Returns Qiang Ye, Harbin Institute of Technology, School of Management, Harbin, China, yeqiang@hit.edu.cn, Xianwei Liu Internet search frequency on stocks has been widely used to measure investor attention in recent studies. Researchers found that weekly searching frequency strongly associated with weekly returns for certain stocks. But we have limited knowledge about the heterogeneity of Internet searches under different circumstances and its varying impact on stock market. In this study, we seek to explore whether searches done on different circumstances guarantee equal attention. Chair: Gordon Burtch, Assistant Professor, University of Minnesota, 321 19th Ave. S., Minneapolis, MN, 55455, United States of America, gburtch@umn.edu 1 - Motivating Group Donation: Evidence from a Large Field Experiment Tianshu Sun, University of Maryland Smith School of Business, 3330 Van Munching Hall, College Park, MD, 20740-2840, United States of America, tianshusun@rhsmith.umd.edu, Gordon Gao, Ginger Zhe Jin Using a randomized field experiment involving 80,000 participants, we study how mobile messaging can leverage recipients’ social connections to increase blood donation. We find 1) blood banks can motivate group formation to increase donation, but only with group reward; 2) group reward works through a sorting mechanism; 3) participants donate more blood when donating in a group. Our study provides insights on the optimal design of mobile messaging for charities to leverage donors’ social network 2 - Field Experiment on the Impact of Recommender Systems on Sales Volume and Diversity Dokyun Lee, Carnegie Mellon University, Pittsburgh, PA, United States of America, leedokyun@gmail.com, Kartik Hosanagar We investigate the impact of collaborative filtering recommender algorithms, commonly used in e-commerce, on sales volume and diversity. We do this by running a randomized field experiment with a top retailer in North America. We show results for sales volume and diversity. We further investigate the genre cross-purchase behavior to shed insight into mechanism behind diversity shift. MA25 25-Room 402, Marriott Examining the Social Crowd Sponsor: Information Systems Sponsored Session

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