A closer look at adaptive regret

For the prediction with expert advice setting, we consider methods to construct algorithms that have low adaptive regret. The adaptive regret of an algorithm on a time interval [t1,t2] is the loss of the algorithm minus the loss of the best expert over that interval. Adaptive regret measures how well the algorithm approximates the best expert locally, and so is different from, although closely related to, both the classical regret, measured over an initial time interval [1,t], and the tracking regret, where the algorithm is compared to a good sequence of experts over [1,t]. We investigate two existing intuitive methods for deriving algorithms with low adaptive regret, one based on specialist experts and the other based on restarts. Quite surprisingly, we show that both methods lead to the same algorithm, namely Fixed Share, which is known for its tracking regret. We provide a thorough analysis of the adaptive regret of Fixed Share. We obtain the exact worst-case adaptive regret for Fixed Share, from which the classical tracking bounds follow. We prove that Fixed Share is

A closer look at adaptive regret

For the prediction with expert advice setting, we consider methods to construct algorithms that have low adaptive regret. The adaptive regret of an algorithm on a time interval [t1,t2] is the loss of the algorithm minus the loss of the best expert over that interval. Adaptive regret measures how well the algorithm approximates the best expert locally, and so is different from, although closely related to, both the classical regret, measured over an initial time interval [1,t], and the tracking regret, where the algorithm is compared to a good sequence of experts over [1,t]. We investigate two existing intuitive methods for deriving algorithms with low adaptive regret, one based on specialist experts and the other based on restarts. Quite surprisingly, we show that both methods lead to the same algorithm, namely Fixed Share, which is known for its tracking regret. We provide a thorough analysis of the adaptive regret of Fixed Share. We obtain the exact worst-case adaptive regret for Fixed Share, from which the classical tracking bounds follow. We prove that Fixed Share is optimal for adaptive regret: the worst-case adaptive regret of any algorithm is at least that of an instance of Fixed Share

Robust Visual Tracking by Exploiting the Historical Tracker Snapshots

© 2015 IEEE. Variations of target appearances due to illumination changes, heavy occlusions and abrupt motions are the major factors for tracking failures. In this paper, we show that these failures can be effectively handled by exploiting the trajectory consistency between the current tracker and its historical trained snapshots. Here, we propose a Scale-adaptive Multi-Expert (SME) tracker, which combines the current tracker and its historical trained snapshots to construct a multi-expert ensemble. The best expert in the ensemble is then selected according to the accumulated trajectory consistency criteria. The base tracker estimates the translation accurately with regression based correlation filter, and an effective scale adaptive scheme is introduced to handle scale changes on-the-fly. SME is extensively evaluated on the 51 sequences tracking benchmark and VOT2015 dataset. The experimental results demonstrate the excellent performance of the proposed approach against state-of-the-art methods with real-time speed

Expert System Selection Topics Thesis Title With Forward Chaining Method Web-Based

Expert Systems are computer-based applications that are used to solve problems as the expert thinks. Many college students majoring in Information Technology are difficult to get the thesis title topic even though it has been reading many journals and looking for some references. Therefore to make it easier college students, then the author wants to create an application where college students majoring in Information Technology can more easily get the thesis title topic so the work of thesis becomes more fluent and not obstructed. This app is web based. In system design, the author used several methods in his research that is method of Analyze, Design, and Implementation. Methods in the design of this expert system even this also used forward chaining method as tracking ahead and best first search method. And also using data collection method mean literature study and questionnaire from system that has been created. The result of Expert System of Thesis Title Topic Selection with Forward Chaining method web based expected to be useful and helpfully college students in getting the thesis title topic. Based on questionnaire that has been shared and filled, it can be said that the Expert System of Thesis Title Topic Selection with Forward Chaining Method Web Based is helpful and beneficial for the college students because it helps college student Information Technology in getting Thesis Title

The on-line shortest path problem under partial monitoring

The on-line shortest path problem is considered under various models of partial monitoring. Given a weighted directed acyclic graph whose edge weights can change in an arbitrary (adversarial) way, a decision maker has to choose in each round of a game a path between two distinguished vertices such that the loss of the chosen path (defined as the sum of the weights of its composing edges) be as small as possible. In a setting generalizing the multi-armed bandit problem, after choosing a path, the decision maker learns only the weights of those edges that belong to the chosen path. For this problem, an algorithm is given whose average cumulative loss in n rounds exceeds that of the best path, matched off-line to the entire sequence of the edge weights, by a quantity that is proportional to 1/\sqrt{n} and depends only polynomially on the number of edges of the graph. The algorithm can be implemented with linear complexity in the number of rounds n and in the number of edges. An extension to the so-called label efficient setting is also given, in which the decision maker is informed about the weights of the edges corresponding to the chosen path at a total of m << n time instances. Another extension is shown where the decision maker competes against a time-varying path, a generalization of the problem of tracking the best expert. A version of the multi-armed bandit setting for shortest path is also discussed where the decision maker learns only the total weight of the chosen path but not the weights of the individual edges on the path. Applications to routing in packet switched networks along with simulation results are also presented.Comment: 35 page