12,097 research outputs found
Improving Estimation in Functional Linear Regression with Points of Impact: Insights into Google AdWords
The functional linear regression model with points of impact is a recent
augmentation of the classical functional linear model with many practically
important applications. In this work, however, we demonstrate that the existing
data-driven procedure for estimating the parameters of this regression model
can be very instable and inaccurate. The tendency to omit relevant points of
impact is a particularly problematic aspect resulting in omitted-variable
biases. We explain the theoretical reason for this problem and propose a new
sequential estimation algorithm that leads to significantly improved estimation
results. Our estimation algorithm is compared with the existing estimation
procedure using an in-depth simulation study. The applicability is demonstrated
using data from Google AdWords, today's most important platform for online
advertisements. The \textsf{R}-package \texttt{FunRegPoI} and additional
\textsf{R}-codes are provided in the online supplementary material
Rec4Ad: A Free Lunch to Mitigate Sample Selection Bias for Ads CTR Prediction in Taobao
Click-Through Rate (CTR) prediction serves as a fundamental component in
online advertising. A common practice is to train a CTR model on advertisement
(ad) impressions with user feedback. Since ad impressions are purposely
selected by the model itself, their distribution differs from the inference
distribution and thus exhibits sample selection bias (SSB) that affects model
performance. Existing studies on SSB mainly employ sample re-weighting
techniques which suffer from high variance and poor model calibration. Another
line of work relies on costly uniform data that is inadequate to train
industrial models. Thus mitigating SSB in industrial models with a
uniform-data-free framework is worth exploring. Fortunately, many platforms
display mixed results of organic items (i.e., recommendations) and sponsored
items (i.e., ads) to users, where impressions of ads and recommendations are
selected by different systems but share the same user decision rationales.
Based on the above characteristics, we propose to leverage recommendations
samples as a free lunch to mitigate SSB for ads CTR model (Rec4Ad). After
elaborating data augmentation, Rec4Ad learns disentangled representations with
alignment and decorrelation modules for enhancement. When deployed in Taobao
display advertising system, Rec4Ad achieves substantial gains in key business
metrics, with a lift of up to +6.6\% CTR and +2.9\% RPM
COPR: Consistency-Oriented Pre-Ranking for Online Advertising
Cascading architecture has been widely adopted in large-scale advertising
systems to balance efficiency and effectiveness. In this architecture, the
pre-ranking model is expected to be a lightweight approximation of the ranking
model, which handles more candidates with strict latency requirements. Due to
the gap in model capacity, the pre-ranking and ranking models usually generate
inconsistent ranked results, thus hurting the overall system effectiveness. The
paradigm of score alignment is proposed to regularize their raw scores to be
consistent. However, it suffers from inevitable alignment errors and error
amplification by bids when applied in online advertising. To this end, we
introduce a consistency-oriented pre-ranking framework for online advertising,
which employs a chunk-based sampling module and a plug-and-play rank alignment
module to explicitly optimize consistency of ECPM-ranked results. A -based weighting mechanism is adopted to better distinguish the importance
of inter-chunk samples in optimization. Both online and offline experiments
have validated the superiority of our framework. When deployed in Taobao
display advertising system, it achieves an improvement of up to +12.3\% CTR and
+5.6\% RPM
Capacity-building activities related to climate change vulnerability and adaptation assessment and economic valuation for Fiji
The Terms of Reference for this work specified three objectives to the Fiji component: Objective 1a: to provide a prototype FIJICLIM model (covered under PICCAP funding)
Objective 1b: to provide training and transfer of FIJICLIM
Objective 1c: to present and evaluate World Bank study findings and to identify future directions for development and use of FIJICLIM (2-day workshop)
Proceedings of the training course and workshop were prepared by the Fiji Department of Environment. The summaries from these proceedings reflect a very high degree of success with the contracted activities
- …