How to measure similarity between two time series?10 answersMeasuring similarity between two time series is a multifaceted task that requires consideration of various aspects such as dimensionality, complexity, and the specific characteristics of the data. A novel approach, SAX-DM, utilizes symbolic aggregate approximation based on double mean representation to address the trade-off between compression ratio and accuracy, effectively preserving the original features and trend information of time series data. This method is particularly useful for high-dimensional and complex time series data.
For interpersonal similarity measurement, a workflow combining existing methods to capture dyadic similarity in a multivariate, timepoint-specific manner has been proposed, illustrating the importance of considering multiple variables and their changes over time. Similarly, heterogeneous similarity calculations have been applied to compare human posture features in time series data, using shape and frequency features, and integrating scores from multiple similarity measures.
In the domain of spacecraft telemetry, an adaptive segmentation-based dynamic time warping algorithm (ASDTW) has been developed to improve the efficiency of similarity measurement by reducing computational overhead. The stock market analysis has seen the introduction of the dynamic multi-perspective personalized similarity measurement (DMPSM), which incorporates weighted segmented stock series and uses Canberra distance embedded in DTW for a more accurate and personalized similarity measurement.
Elastic similarity measures, which allow for alignment of points that do not correspond in timestamps, have been adapted for multivariate time series, demonstrating the importance of considering the specific characteristics of the data. A concept-based approach using fuzzy sets for time series similarity evaluation has been proposed, emphasizing the need for interpretable methods. Lastly, the Local Extrema Dynamic Time Warping (LE-DTW) method offers a parameter-free measure for assessing similarity between long time series, highlighting the challenge of dealing with long-duration data.
These approaches underscore the diversity of methods available for measuring similarity between two time series, each tailored to specific types of data and application requirements.
Is Cosine-Similarity of Embeddings Really About Similarity?5 answersYes, the cosine similarity of embeddings is a crucial metric in various Natural Language Processing (NLP) tasks like question answering, information retrieval, and machine translation. However, research suggests that cosine similarity may underestimate the similarity of frequent words due to differences in representational geometry based on word frequency. This effect is traced back to training data frequency, impacting the accuracy of similarity estimations for high-frequency words across contexts. Despite its importance in NLP tasks, cosine similarity might not fully capture the true similarity of frequent words, as highlighted in studies on BERT embeddings.
How measure text similarity?5 answersText similarity can be measured using various methods. One approach is to use word embeddings, which represent words as vectors in a high-dimensional space. By comparing the vectors of two texts, the similarity between them can be estimated. Another method is to consider the semantic information of the texts by building a semantic network that represents the relationship between the compared texts. This network reflects the semantic, syntactical, and structural knowledge of the texts. Additionally, a combination of word2vec model and TF-IDF can be used to calculate semantic similarity. This method has been applied to measure the similarity of Chinese text data in an online medical community. Finally, the Maxwell-Boltzmann Similarity Measure (MBSM) can be used to find similarities between texts based on the distribution of feature values and the total number of non-zero elements.
What are the psychometric properties for the computerised CORSI task?5 answersThe psychometric properties of the computerized CORSI task were not mentioned in the provided abstracts.
What are the advantages and disadvantages of using cosine as a metric to measure similarity?5 answersCosine similarity has several advantages as a metric to measure similarity. It is widely used in various fields such as large-scale image retrieval and language modeling. It offers low storage cost, high computational efficiency, and good retrieval performance. However, there are also some disadvantages to using cosine similarity. One major drawback is that it yields the same value regardless of the size of the vectors being compared, as long as the angle between them is the same. This can be problematic when comparing vectors of different sizes, such as when comparing the risk profiles of different companies. Another limitation is that cosine similarity does not take into account the semantic meanings of words or phrases, even when using techniques like Natural Language Processing. This can limit its effectiveness in tasks that require a more nuanced understanding of similarity.
What are the different similarity measures used to compare trajectories?5 answersThere are several similarity measures used to compare trajectories. Some of the commonly used measures include dynamic time warping (DTW), longest common subsequence (LCSS), edit distance for real sequences (EDR), Frechet distance, and nearest neighbor distance (NND). These measures have been developed and applied in various fields such as movement ecology, marketing, tourism, traffic, and animal monitoring. Additionally, there are other measures like the Time Warp Edit distance measure (TWEDistance), regression, interpolation, and curve barcodingthat have been used to evaluate similarity between trajectories. These measures take into account different criteria such as shape, speed, distance traveled, duration, and visited sites to determine the similarity between trajectories.