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The first step in preventing school violence is to understand the extent and nature of the problem. According to CDC’s Youth Risk Behavior Survey (YRBS), nearly 8% of students had been in a physical fight on school property one or more times during the 12 months before the survey.
The Centers for Disease Control and Prevention (CDC), the U. Nationwide, about 6% of students had not gone to school at least 1 day during the 30 days before the survey because they felt they would be unsafe at school or on their way to or from school.
The system creates a content-based profile of users based on a weighted vector of item features.
The weights denote the importance of each feature to the user and can be computed from individually rated content vectors using a variety of techniques.
A widely used algorithm is the tf–idf representation (also called vector space representation). A history of the user's interaction with the recommender system.
To create a user profile, the system mostly focuses on two types of information: 1. Basically, these methods use an item profile (i.e., a set of discrete attributes and features) characterizing the item within the system.
The differences between collaborative and content-based filtering can be demonstrated by comparing two popular music recommender systems – and Pandora Radio.
Recommender systems are a useful alternative to search algorithms since they help users discover items they might not have found otherwise.For example, the k-nearest neighbor (k-NN) approach Collaborative filtering is based on the assumption that people who agreed in the past will agree in the future, and that they will like similar kinds of items as they liked in the past.When building a model from a user's behavior, a distinction is often made between explicit and implicit forms of data collection.For example, recommending news articles based on browsing of news is useful, but would be much more useful when music, videos, products, discussions etc.from different services can be recommended based on news browsing.