Peiji Chen

Ad serving using a compact allocation plan

A large fraction of online display advertising is sold via guaranteed contracts: a publisher guarantees to the advertiser a certain number of user visits satisfying the targeting predicates of the contract. The publisher is then tasked with solving the ad serving problem ---given a user visit, which of the thousands of matching contracts should be displayed, so that by the expiration time every contract has obtained the requisite number of user visits. The challenges of the problem come from (1) the sheer size of the problem being solved, with tens of thousands of contracts and billions of user visits, (2) the unpredictability of user behavior, since these contracts are sold months ahead of time, when only a forecast of user visits is available and (3) the minute amount of resources available online, as an ad server must respond with a matching contract in a fraction of a second. We present a solution to the guaranteed delivery ad serving problem using compact allocation plans. These plans, computed offline, can be efficiently queried by the ad server during an ad call; they are small, using only O(1) space for contract; and are stateless, allowing for distributed serving without any central coordination. We evaluate this approach on a real set of user visits and guaranteed contracts and show that the compact allocation plans are an effective way of solving the guaranteed delivery ad serving problem.

15.1: Invited Paper: A 46‐inch TFT‐LCD HDTV Technology with Color Management and Image Quality Enhancement

We have developed a 46-inch TFT-LCD HDTV (high definition television — 1080p) with digital color management and image enhancement technologies. The panel uses premium MVA (multi-domain vertical alignment liquid crystals, and is fabricated on generation-5 glass substrates with ODF process (one drop filled liquid crystal process). It adopts the true wide format of 16:9. The viewing angle at a CR (contrast ratio) of 10:1 is greater than 170° in all directions. In the normal direction, CR is above 800. For conventional color management and image quality enhancement, we optimized the color performance between color-filters and backlight units as well as the properties of VA LC and polarizers. The outcomes include high color gamut (75% of NTSC) and brightness (> 600 nits). More advanced digital color management techniques include the application of vivid color mapping, and gamma correction by signal processing. For the quality of fast moving pictures, we have developed a new driving approach in conjunction with advanced VA LCs to achieve a response speed of 8 ms in average. The new approach compensates the slow transition between gray levels.