2015 Informs Annual Meeting

TD37

INFORMS Philadelphia – 2015

TD37 37-Room 414, Marriott Therapy and Treatment Contributed Session Chair: Animesh Garg, PhD Student, UC Berkeley, 4141 Etcheverry Hall, Berkeley, CA, 94720-1777, United States of America, garg.animesh@gmail.com 1 - Assessment of a Novel Device for Elbow Rehabilitation in Humans Aline Callegaro, Researcher, UFRGS, 99 Osvaldo Aranha Avenue, 5 Floor, Porto Alegre, RS, 90035190, Brazil, nimacall@gmail.com, Carlos Fernando Jung, Clarissa Brusco, Marcelo Gava Pompermayer, Márcia Elisa Echeveste, Carla Schwengber ten Caten This study aimed to assess a novel device for elbow rehabilitation in humans. The functional prototype assessment was based on data collection in two stages: application of local muscle vibration; and its association with Continuous Passive Motion. Two way ANOVA was used to analyse the main factors. An average increase of the muscle electrical activation resulted in first stage. The main factors (frequency, sex, and treatment) had significant effect, as well as a few interactions. 2 - Minimizing Metastatic Risk in Radiotherapy Fractionation Schedules Hamidreza Badri, Graduate Student, University of Minnesota, ISyE Departemnt, 111 Church Street S.E., Minneapolis, MN, 55455, United States of America, badri019@umn.edu, Jagdish Ramakrishnan, Kevin Leder The treatment of metastatic cancer remains an extremely challenging problem. Here we consider the problem of developing fractionated irradiation schedules that minimize production of metastatic cancer cells. We observe that the resulting fractionation schedules are different than those that result from more standard objectives such as minimization of final primary tumor volume. Delivering large doses in small fractions is suggested even in cases when a/b value of the tumor is large. 3 - Customized 3D Printed Implants with Internal Channels for Intracavitary High Dose Rate Brachytherapy Animesh Garg, PhD Student, UC Berkeley, 4141 Etcheverry Hall, University of California, Berkeley, CA, 94720-1777, United States of America, garg.animesh@gmail.com, Jean Pouliot, J. Adam M. Cunha, I-Chow Hsu, Alper Atamturk, Ken Goldberg High-Dose Rate Brachytherapy is an internal radiation therapy frequently used for cancer treatment. Radioactive sources are briefly placed proximal to tumors. Current methods for intracavitary HDR-BT use generic templates which limits dose distribution to a small set of linear channels. We propose the use of algorithmically customized 3D Printed implants with curved internal channels that fit cavities without tissue puncture and aim to improve dose distribution and treatment quality. 4 - Surgery Sequencing and Scheduling in Multiple ORs with PACU Constraints Miao Bai, Lehigh University, 200 W Packer Ave, Bethlehem, PA, 18015, United States of America, mib411@lehigh.edu, Gregory Tonkay, Robert Storer We study a multiple-OR surgery sequencing and scheduling problem with PACU constraints. To minimize the cost incurred by waiting, idleness, OR blocking and overtime, a two-stage solution scheme is proposed. In the first stage, a time- indexed integer program is formulated and solved by Lagrangian relaxation and dynamic programming to determine surgery sequences. Given surgery sequences in all ORs, scheduled times of patients are found in the second stage by a sample- gradient-based algorithm. TD38 38-Room 415, Marriott Probability Contributed Session Chair: Gene Hahn, Associate Professor, Salisbury University, 1101 Camden Ave., Salisbury, MD, 21801, United States of America, edhahn@salisbury.edu 1 - Fluctuation Analysis and the Marked Poisson Process Randy Robinson, Bemidji State University, Bemidji, MN, United States of America, rrobinson@bemidjistate.edu This presentation studies the marked point process with position dependent marking. The focus was on predicting the first passage time of the marked random walk when exiting a given rectangular set and the value of the process upon the exit. A new density function for the related processes has been obtained: a product of a negative exponential and modified Bessel functions

2 - Moments of a Random Set Kemal Gursoy, Rutgers University, 100 Rockafeller Road, Department of MSIS, Piscataway, NJ, 08854, United States of America, kgursoy@rci.rutgers.edu Let X be a random subset of the n-dimensional Euclidean space. Then the moments of the measure of X could be constructed by the Lebesgue integral of the probability measure of every point in X, over the n-dimensional Euclidean space. 3 - A New Representation for the Stationary Distribution of Markov Chains Patrick Buckingham, Clemson University, Mathematical Sciences, Clemson, SC, United States of America, pbuckin@clemson.edu, Brian Fralix We present a new representation for the stationary distribution of ergodic Markov chains, as well as analogous representations for Laplace transforms of transition functions associated with such chains. Applications to hysteretic queues and other models will be discussed. 4 - Queueing Systems with Adaptive Service Rates In many service systems, for example call centers, the service rate could be considered as a time-dependent decision variable to improve and stabilize the performance of a queueing system. We present an M(t)/M(t)/c queueing model with adaptive service rates. The SBC-approach is used to approximate the time- dependent behaviour of by stationary models. This results in non-linear optimization problem. Numerical examples show the benefits of assuming the service rate as a decision variable. 5 - Modeling with the Tilted Beta Distribution Gene Hahn, Associate Professor, Salisbury University, 1101 Camden Ave., Salisbury, MD, 21801, United States of America, edhahn@salisbury.edu The beta distribution has an important limitation for the modeling of bounded data. Its density is either zero or infinite at the endpoints except for special cases. This makes modeling certain kinds of data difficult. The tilted beta distribution can be used to easily model this data. We adopt a Bayesian perspective and examine its usage in modeling real-world data. TD39 39-Room 100, CC Product Brand Differentiation and Pricing Decisions Cluster: Operations/Marketing Interface Invited Session Chair: Ruixia Shi, California State University, Fullerton, 800 N. State College Blvd., Fullerton, CA, 92834, United States of America, sandy.shi@gmail.com 1 - New Product Pricing Strategy in the Social Media Era Gou Qinglong, Associate Professor, University of Science & Technology of China, No.96, JinZhai Road Baohe District, Hefei, China, tslg@ustc.edu.cn, Kumar Subodha, Xiuli He, Juzhi Zhang With the popularity of various social media platforms, the impacts of the word of mouth effect and the reference price effect on a consumer’s purchasing behavior have been significantly amplified in the current era. We incorporate these two effects into a two period pricing model to investigate whether and in which condition should a firm utilize a skimming or a penetration price strategy. Our results show how these two effects influence a firm’s pricing strategy when he launches a new product. 2 - Competition and Coordination in Online Retailers and Express Companies Yihong Hu, Assistant Professor, Tongji University, yhhu@tongji.edu.cn We consider an online market as Taobao with homogenous and heterogeneous consumers sensitive to service quality. Retailers collect a separate product price plus shipping fee from consumers. They treat shipping fee as a source of revenue by asking a large discount of shipping fee from shippers. We use game-theoretic framework to study the competition and coordination between retailers and shippers under different scenarios. The study finds that retailers’ behavior increases consumers’ benefit. Raik Stolletz, University of Mannheim, Room SO 230, Schloss Schneckenhof Ost, Mannheim, Germany, stolletz@bwl.uni-mannheim.de, Jannik Vogel

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