Online Product Quantization

Approximate nearest neighbor (ANN) search has achieved great success in many tasks. However, existing popular methods for ANN search, such as hashing and quantization methods, are designed for static databases only. They cannot handle well the database with data distribution evolving dynamically, due to the high computational effort for retraining the model based on the new database. In this paper, we address the problem by developing an online product quantization (online PQ) model and incrementally updating the quantization codebook that accommodates to the incoming streaming data. Moreover, to further alleviate the issue of large scale computation for the online PQ update, we design two budget constraints for the model to update partial PQ codebook instead of all. We derive a loss bound which guarantees the performance of our online PQ model. Furthermore, we develop an online PQ model over a sliding window with both data insertion and deletion supported, to reflect the real-time behaviour of the data. The experiments demonstrate that our online PQ model is both time-efficient and effective for ANN search in dynamic large scale databases compared with baseline methods and the idea of partial PQ codebook update further reduces the update cost.Comment: To appear in IEEE Transactions on Knowledge and Data Engineering (DOI: 10.1109/TKDE.2018.2817526

Strategic Vertical Pricing in the U.S. Butter Market

This article develops a methodology for empirically analyzing vertically strategic interactions in a multi-level supply channel. The model is used to analyze the vertical channel for U.S. butter manufacturing and retailing. Aggregating products to the firm level and using a nonlinear AIDS demand system under alternative strategic pricing assumptions is estimated using full information maximum likelihood (FIML) for seven geographic markets from 1998-2002. The market demand for butter was found to very price elastic. Furthermore, cross price elasticities between private labels and the two large national brands were also very elastic. The selected market structure was one indicating category profit maximization of national brands (separate from private label) at the retail level, Vertical Nash competition in the vertical channel, and Bretrand competition at the manufacturing level. Our results strongly suggest that the retail market for food products is impacted by the underlying vertical structure. The study provides useful measures of imperfect competition in the retail manufacturing sector.Vertical interaction, market structure, strategic pricing, market power, AIDS model, butter., Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Industrial Organization, L13, L22, L66,

Relationship of Driver Oncogenes to Long-Term Pemetrexed Response in Non--Small-Cell Lung Cancer.

BackgroundPemetrexed is approved in the treatment of advanced stage nonsquamous non-small-cell lung cancer (NSCLC). The length of response is variable, and we thus sought to identify which clinicopathologic characteristics are associated with long-term disease control with pemetrexed.Patients and methodsPatients with metastatic NSCLC received pemetrexed (with or without bevacizumab) for 12 months or longer, either as maintenance treatment after first-line platinum-based chemotherapy or as subsequent treatment. Clinical and pathologic characteristics were collected.ResultsOf a total of 196 patients who received pemetrexed starting in 2007, 25 patients were identified who received pemetrexed for over 1 year. Of these, 15 patients received pemetrexed with or without bevacizumab as maintenance treatment and 10 patients received pemetrexed as subsequent treatment. Fifteen (60%) of 25 patients had an oncogenic driver mutation as follows: 5 (20%) had ROS1 gene rearrangements, 4 (16%) had ALK gene rearrangements, 3 (12%) had KRAS mutations, 2 (8%) had epidermal growth factor receptor (EGFR) mutations, and 1 (4%) had an NRAS mutation. The median overall survival was 42.2 months (95% confidence interval, 37.4-61.3) and median progression-free survival was 22.1 months (95% confidence interval, 15.1-29.1). Patients with an oncogenic driver mutation had significantly better progression-free survival (P = .006) and overall survival (P = .001).ConclusionAmong patients with NSCLC who received pemetrexed for an extended time, those with ALK and ROS1 gene rearrangements were proportionally overrepresented compared with that anticipated in a general nonsquamous NSCLC population, and patients with oncogenic driver mutations had improved outcomes