- September 5, 2013
- Posted by: graymatt_gray
- Category: Uncategorized
recommendation algorithm work
Canada Goose online The goal of the YouTube video recommendation system is plain: to provide personalized high quality video recommendations to its users. The way YouTube is able to accomplish this goal is anything but. First, the amount of video uploaded to YouTube is staggering. Second, much of this video has poor metadata such as incomplete or irrelevant titles and descriptions. Third, the metrics that are available to the YouTube recommender for measuring user interest are much vaguer than those available to other recommender systems like Amazon. For example, purchasing a product is a clearer indicator of user interest than is watching a Canada Goose online video. Furthermore, YouTube video recommendations must be fresh as many YouTube videos have a short shelf life, and older videos will often be of little interest to users. Canada Goose online
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The YouTube recommendation system draws its data from two main sources. The first is content data, such as metadata like titles and descriptions. To do so, it Canada Goose Coats On Sale makes use of a method called co visitation or association rule mining to identify canada goose clearance sale pairs of videos watched in a given session and canada goose black friday sale compute a relatedness score for these videos. The system then combines the related videos’ association rules with a user’s activity on the site, such as videos watched and favorited by the user, to create what it calls a seed set. Once this is done, it traces paths of canada goose uk outlet related videos out from this seed set to generate candidate recommendations. Think of the seed set as the center of a web and the potential recommendation candidates as points on that web extending outwards from the center. Video quality signals include metrics such as view count, video ratings, comments, favorites and sharing activities. User specificity signals are used to boost videos that are similar to a user’s unique preferences. Seed video properties such as view count and time of watching are used to generate these user specificity signals. In order to increase diversity, recommendation candidate videos that are too similar to one another are removed and are replaced with more varied content. At the time of the paper’s publication, recommended videos accounted for approximately 60% cheap canada goose uk of clicks on the homepage. Furthermore, it was found that over a 21 day period, the click through rate (CTR) for recommended videos performed at 207% of the average CTR for Most Viewed videos.
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canada goose deals While the YouTube recommender system has performed well, it seems there is room for improvement. Indeed, other recommender systems, such as the Trouvus engine, have achieved greater results than those documented in the YouTube paper. Furthermore, it should be noted that content providers that use YouTube to host content, will not necessarily have their own content recommended to users by the YouTube https://www.canadagoose-jackets-online.com system. It makes sense, therefore, for such content providers, assuming they have their own digital properties (on which they can place their videos), to look into acquiring their own recommender system. canada goose deals
canada goose black friday sale SOURCE : How Does the YouTube Recommendation Canada Goose Outlet System Work? canada goose black friday sale
Google changed the YouTube algorithm in 2016 to a new one made by their Artificial intelligence company Deep canada goose uk black friday Mind. It uses deep learning neural networks to optimise for the user’s expected watch time.
The algorithm has two steps, both of which use multi layer neural networks.
canada goose coats 1) Candidate generation. This selects a few hundred possible videos for the user from YouTube’s canadian goose jacket entire corpus of videos. It uses quite a crude personalisation criteria based on videos also commonly watched by people who watch similar videos to the user, and similarity of demographics. canada goose coats
canada goose store 2) Ranking. The smaller subset of videos are each scored for expected watch time. This uses hundreds of features to try to predict the watch time. number of videos the user has watched in the same channel, search query made by the user before watching the video, how long ago the user watched a video on the same topic. canada goose store
canadian goose jacket Part of the reason for using two stages is because of the scale of the problem. YouTube have a very large number of videos that rapidly update. This means, for example, it is so far impractical to just run the second canada goose uk shop stage algorithm across all videos. canadian goose jacket
In my view, this two stage algorithm with this criteria leads to YouTube recommending short term addictive videos, selected from a small set of popular videos.
While it uses sophisticated algorithms for prediction, it has very unsophisticated criteria which those algorithms are optimising for. Think of getting TV recommendations from a savant toddler, rather than say a professional TV critic.
canada goose Full details in Google’s paper about the algorithm: Deep Neural Networks for YouTube Recommendations canada goose
Canada Goose sale The previous answer did not really answer the question. I have talked to a few former youtube canada goose clearance engineers and I have gotten the impression that youtube uses some kind of similarity metrics. Look up Jaccard Similarity and Cosine Similarity, and Lj distances. Canada Goose sale
canada goose coats on sale Typically canada goose store youll have some kind of vector that represents all of the uk canada goose outlet videos you have watched. And then we can compare this vector, using these various similarity metrics, to the vectors of other people to try to find a close match. If you are a canada goose close match, then videos that one person watches are likely relevant to the other person. But there is a problem! These vectors are of super high dimension, and doing calculations with them is expensive. The Johnson Lindenstrauss lemma helps us solve this problem. canada goose coats on sale
Canada Goose Outlet Basically this lemma says that given a bunch vectors in a canada goose coats large subspace, we can project these vectors onto a much smaller subspace such that the distances (calculated by the similarity metrics stated above) between these vectors is almost entirely preserved. The way we can do this is quite amazing. We just multiply all of the original k vectors by a k by d matrix buy canada goose jacket whose entries are drawn independently from a Gaussian distribution, where d Canada Goose Outlet
Canada Goose Jackets In a recent paper published by Google, YouTube engineers analyzed in greater detail the inner workings of YouTube’s recommendation algorithm. The paper was presented on the 10th ACM Conference on Recommender Systems last week in Boston. Canada Goose Jackets
Canada Goose Parka YouTube recommendations are driven by Google Brain, which was recently opensourced as TensorFlow. By using TensorFlow one can experiment with different deep neural network Canada Goose Jackets architectures using distributed training. The system consists of two neural networks. The first one, canada goose coats on sale candidate generation, takes as input user’s buy canada goose jacket cheap watch history and using Canada Goose Parka collaborative filtering selects videos in the range of hundreds. An important distinction between development and final deployment to production is that during development Google uses offline metrics for the performance of algorithms but the final decision comes from live A/B testing between the best performing Canada Goose sale algorithms. Canada Goose Parka
buy canada goose jacket Candidate generation uses the implicit feedback of video watches by users to train the model. Explicit feedback such as a thumbs up or a thumbs down of a video are in general rare compared to implicit and this is an even bigger issue with long tail videos that are not popular. To accelerate training of the model for newly uploaded videos, the age of each training example is fed in as a feature. Another key aspect for discovering and surfacing new content is to use all YouTube videos uk canada goose watched, even on partner sites, for training of the algorithm. This way collaborative filtering can pick up viral videos right away. Finally, by adding more features and depth like searches and age cheap Canada Goose of video other than the actual watches, YouTube was able to improve offline holdout precision results. buy canada canada goose outlet goose jacket
canada goose clearance sale The second neural network is used for Ranking the few hundreds of videos in order. This is much simpler as a problem to candidate generation as the number of videos is smaller and more information is available for each video and its relationship with the user. This system uses logistic regression to score each video and then A/B testing is continuously used for further improvement. The metric used here is expected watch time, as expected click can promote clickbait. To canada goose factory sale train it on watch time rather than clickthrough rate, the system uses a weighted variation of logistic regression with watch time as the weight for positive interactions and a unit weight for negative ones. This works out partly because the fraction of positive impressions is Canada Goose Online small compared to total canada goose clearance sale.
