Yixuan Zhai

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—We consider a dynamic pricing problem with unknown demand models. In this problem, a seller offers prices sequentially to a stream of potential customers and observes either success or failure in each sales attempt. The underlying demand model is unknown and can take one of two possible forms. We show that the problem can be formulated as a two-armed(More)
We consider the dynamic search of a target located in one of K cells. At each time, one cell is searched, and the search result is subject to false alarms. The objective is a policy that governs the sequential selection of the cells to minimize the error probability of detecting the whereabouts of the target within a fixed time horizon. We show that the(More)
We consider a dynamic pricing problem under unknown demand models. In this problem a seller offers prices to a stream of customers and observes either success or failure in each sale attempt. The underlying demand model is unknown to the seller and can take one of N possible forms. In this paper, we show that this problem can be formulated as a multi-armed(More)
OBJECTIVE Chordomas in children and adolescents are rare, and minimal published information is available. Our aim was to research clinical features and prognostic factors associated with clival chordomas in younger patients. METHODS The study included 25 patients (10 males and 15 females). Average follow-up time was 42.95 months (range, 2-108 months).(More)
OBJECTIVE We sought to compare the prognosis of clival chordomas with different dural penetration and establish the relationship between dural penetration and platelet-derived growth factor receptor (PDGFR)-β signaling pathway. METHODS Tumors in Type I (33 cases) showed limited dural penetration, while those in Type II (34 cases) had more serious dural(More)
OBJECTIVE To investigate surgical (aspiration and resection) outcome of encapsulated brain abscess in superficial non-eloquent area. METHODS We searched Pubmed, Embase and Cochrane Library from the foundation of the database till December 2013. Two researchers screened literatures independently, assessed the quality of the included studies and extracted(More)
We consider an oligopoly dynamic pricing problem where the demand model is unknown and the sellers have different marginal costs. We formulate the problem as a repeated game with incomplete information. We develop a dynamic pricing strategy that leads to a Pareto-efficient and subgame-perfect equilibrium and offers a bounded regret over an infinite horizon,(More)
OBJECTIVE Skull base chordomas are clinically malignant because of the difficulty of total removal and the high recurrence rate. Because the disease-free survival after surgery is currently unpredictable, there is a need for new parameters obtained from histological analyses of the resection specimen that allows a risk stratification of patients with(More)
We consider the shortest path problem in a communication network with random link costs drawn from unknown distributions. A realization of the total end-to-end cost is obtained when a path is selected for communication. The objective is an online learning algorithm that minimizes the total expected communication cost in the long run. The problem is(More)
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