Interactive Response Times Research Articles

A novel framework for predicting active flow control by combining deep reinforcement learning and masked deep neural network

Active flow control (AFC) through deep reinforcement learning (DRL) is computationally demanding. To address this, a masked deep neural network (MDNN), aiming to replace the computational fluid dynamics (CFD) environment, is developed to predict unsteady flow fields under the influence of arbitrary object motion. Then, a novel DRL-MDNN framework that combines the MDNN-based environment with the DRL algorithm is proposed. To validate the reliability of the framework, a blind test in a pulsating baffle system is designed. Vibration damping is considered to be the objective, and a traditional DRL-CFD framework is constructed for comparison. After training, a spatiotemporal evolution of 200 time steps under the influence of arbitrary object motion is predicted by the MDNN. The details of the flow field are compared with the CFD results, and a relative error within 5% is achieved, which satisfies the accuracy of serving as an interactive environment for DRL algorithms. The DRL-MDNN and traditional DRL-CFD frameworks are then applied to the pulsating baffle system to find the optimal control strategy. The results indicate that both frameworks achieve similar control performance, reducing vibration by 90%. Considering the resources expended in establishing the database, the computational resource consumption of the DRL-MDNN framework is reduced by 95%, and the interactive response time during each episode is decreased by 98.84% compared to the traditional DRL-CFD framework.

HMPT: a human–machine cooperative program translation method

Program translation aims to translate one kind of programming language to another, e.g., from Python to Java. Due to the inefficiency of translation rules construction with pure human effort (software engineer) and the low quality of machine translation results with pure machine effort, it is suggested to implement program translation in a human–machine cooperative way. However, existing human–machine program translation methods fail to utilize the human’s ability effectively, which require human to post-edit the results (i.e., statically modified directly on the model generated code). To solve this problem, we propose HMPT (Human-Machine Program Translation), a novel method that achieves program translation based on human–machine cooperation. It can (1) reduce the human effort by introducing a prefix-based interactive protocol that feeds the human’s edit into the model as the prefix and regenerates better output code, and (2) reduce the interactive response time resulted by excessive program length in the regeneration process from two aspects: avoiding duplicate prefix generation with cache attention information, as well as reducing invalid suffix generation by splicing the suffix of the results. The experiments are conducted on two real datasets. Results show compared to the baselines, our method reduces the human effort up to 73.5% at the token level and reduces the response time up to 76.1%.

ProS: data series progressive k-NN similarity search and classification with probabilistic quality guarantees

Existing systems dealing with the increasing volume of data series cannot guarantee interactive response times, even for fundamental tasks such as similarity search. Therefore, it is necessary to develop analytic approaches that support exploration and decision making by providing progressive results, before the final and exact ones have been computed. Prior works lack both efficiency and accuracy when applied to large-scale data series collections. We present and experimentally evaluate ProS, a new probabilistic learning-based method that provides quality guarantees for progressive nearest neighbor (NN) query answering. We develop our method for k-NN queries and demonstrate how it can be applied with the two most popular distance measures, namely Euclidean and dynamic time warping. We provide both initial and progressive estimates of the final answer that are getting better during the similarity search, as well suitable stopping criteria for the progressive queries. Moreover, we describe how this method can be used in order to develop a progressive algorithm for data series classification (based on a k-NN classifier), and we additionally propose a method designed specifically for the classification task. Experiments with several and diverse synthetic and real datasets demonstrate that our prediction methods constitute the first practical solutions to the problem, significantly outperforming competing approaches.

Expressive querying for accelerating visual analytics

Data visualization is the primary means by which data analysts explore patterns, trends, and insights in their data. Unfortunately, existing visual analytics tools offer limited expressiveness and scalability when it comes to searching for visualizations over large datasets, making visual data exploration labor-intensive and time-consuming. In this work, we introduce the problem of visualization search and highlight two underlying challenges of search enumeration and visualization matching. To address them, we first present our work on Zenvisage that helps enumerate large collections of visualizations and supports simple visualization matching with the help of an interactive interface and an expressive visualization query language. For more finegrained and flexible visualization matching, including search for underspecified and approximate patterns, we extend Zenvisage to develop ShapeSearch. ShapeSearch supports a novel shape querying algebra that helps express a large class of pattern queries that are hard to specify with existing systems. ShapeSearch exposes multiple specification mechanisms: sketch, natural-language, and visual regular expressions that help users easily issue shape queries, while applying query-aware and perceptually-aware optimizations to efficiently execute them within interactive response times. To conclude, we discuss a number of open research problems to further improve the usability and performance of both Zenvisage and ShapeSearch.

Computational Technologies on Modeling of Museum Interactive Virtual Display Based on User Experience

In order to solve the problems of the traditional museum interactive virtual display modeling methods such as poor clarity, low user satisfaction, and long interactive response time, a museum interactive virtual display modeling method based on user experience was proposed. The museum information collection system is set up to collect 3D point cloud data of exhibits by using the system, and the 3D point cloud data are denoised by the moving least squares method. The museum building data and denoised 3D point cloud data are integrated, and all point cloud data are registered. According to the registration results, the interactive virtual display model of the museum is preliminarily constructed, and the user experience model is used to adjust the parameters of the display model to realize the interactive virtual display modeling of the museum. The simulation results show that the proposed method has a high definition of the interactive virtual display of a museum, the average user satisfaction is 9.45, and the interactive response time is always below 0.4s, which fully verifies the superiority of the proposed method.

Beyond TPC-DS, a benchmark for Big Data OLAP systems (BDOLAP-Bench)

Online Analytical Processing (OLAP) systems with Big Data support allow storing tables of up to tens of billions of rows or terabytes of data. At the same time, these tools allow the execution of analytical queries with interactive response times, thus making them suitable for the implementation of Business Intelligence applications. However, since there can be significant differences in query and data loading performance between current Big Data OLAP tools, it is worthwhile to evaluate and compare them using a benchmark. But we identified that none of the existing approaches are really suitable for this type of system. To address this, in this research we propose a new benchmark specifically designed for Big Data OLAP systems and based on the widely adopted TPC-DS benchmark. To overcome TPC-DS inadequacy, we propose (i) a set of transformations to support the implementation of its sales data mart on any current Big Data OLAP system, (ii) a choice of 16 genuine OLAP queries, and (iii) an improved data maintenance performance metric. Moreover, we validated our benchmark through its implementation on four representative systems.

From Sketching to Natural Language

Data visualization is the primary means by which data analysts explore patterns, trends, and insights in their data. Unfortunately, existing visual analytics tools offer limited expressiveness and scalability when it comes to searching for visualizations over large datasets, making visual data exploration labor-intensive and timeconsuming. We first discuss our prior work on Zenvisage that helps accelerate exploratory data analysis via an interactive interface and an expressive visualization query language, but offers limited flexibility when the pattern of interest is under-specified and approximate. Motivated from our findings from Zenvisage, we develop ShapeSearch, an efficient and flexible pattern-searching tool that enables the search for desired patterns via multiple mechanisms: sketch, natural-language, and visual regular expressions. ShapeSearch leverages a novel shape querying algebra that can express a large class of shape queries and supports query-aware and perceptually-aware optimizations to execute shape queries within interactive response times. To further improve the usability and performance of both Zenvisage and ShapeSearch, we discuss a number of open research problems.

FlashP

Interactive response time is important in analytical pipelines for users to explore a sufficient number of possibilities and make informed business decisions. We consider a forecasting pipeline with large volumes of high-dimensional time series data. Real-time forecasting can be conducted in two steps. First, we specify the part of data to be focused on and the measure to be predicted by slicing, dicing, and aggregating the data. Second, a forecasting model is trained on the aggregated results to predict the trend of the specified measure. While there are a number of forecasting models available, the first step is the performance bottleneck. A natural idea is to utilize sampling to obtain approximate aggregations in real time as the input to train the forecasting model. Our scalable real-time forecasting system FlashP (Flash Prediction) is built based on this idea, with two major challenges to be resolved in this paper: first, we need to figure out how approximate aggregations affect the fitting of forecasting models, and forecasting results; and second, accordingly, what sampling algorithms we should use to obtain these approximate aggregations and how large the samples are. We introduce a new sampling scheme, called GSW sampling, and analyze error bounds for estimating aggregations using GSW samples. We introduce how to construct compact GSW samples with the existence of multiple measures to be analyzed. We conduct experiments to evaluate our solution its alternatives on real data.

Active semi-supervised learning for biological data classification.

Due to datasets have continuously grown, efforts have been performed in the attempt to solve the problem related to the large amount of unlabeled data in disproportion to the scarcity of labeled data. Another important issue is related to the trade-off between the difficulty in obtaining annotations provided by a specialist and the need for a significant amount of annotated data to obtain a robust classifier. In this context, active learning techniques jointly with semi-supervised learning are interesting. A smaller number of more informative samples previously selected (by the active learning strategy) and labeled by a specialist can propagate the labels to a set of unlabeled data (through the semi-supervised one). However, most of the literature works neglect the need for interactive response times that can be required by certain real applications. We propose a more effective and efficient active semi-supervised learning framework, including a new active learning method. An extensive experimental evaluation was performed in the biological context (using the ALL-AML, Escherichia coli and PlantLeaves II datasets), comparing our proposals with state-of-the-art literature works and different supervised (SVM, RF, OPF) and semi-supervised (YATSI-SVM, YATSI-RF and YATSI-OPF) classifiers. From the obtained results, we can observe the benefits of our framework, which allows the classifier to achieve higher accuracies more quickly with a reduced number of annotated samples. Moreover, the selection criterion adopted by our active learning method, based on diversity and uncertainty, enables the prioritization of the most informative boundary samples for the learning process. We obtained a gain of up to 20% against other learning techniques. The active semi-supervised learning approaches presented a better trade-off (accuracies and competitive and viable computational times) when compared with the active supervised learning ones.

SQL for data scientists

The SQL query language is the 'lingua franca' of transactional databases, and is essential for scalable data analytics. Learning SQL requires practical exercises with databases, including those parts of SQL with side-effects such as DDL statements, triggers, and stored procedures. Teaching this effectively to a non-technical audience is a challenge, especially in times of COVID-19 without face-to-face classes. The Grok Learning platform allows to design self-paced online tutorials with auto-graded exercises - but it was originally built for teaching programming languages. In this demo, we show how we extended the Grok platform to teach SQL for Data Scientists with comprehensive online learning. Grok supports a rich user interface with interactive examples where students can explore and experiment with each example query. This is ideal for learning declarative querying. Each query is executed in its own sandbox on a freshly initialised database instance which allows to teach all parts of SQL including DDL statements, stored procedures, triggers and UDFs. At the same time, the platform scales to thousands of concurrent users, while maintaining interactive response times.

Progressive indexes

Interactive exploration of large volumes of data is increasingly common, as data scientists attempt to extract interesting information from large opaque data sets. This scenario presents a difficult challenge for traditional database systems, as (1) nothing is known about the query workload in advance, (2) the query workload is constantly changing, and (3) the system must provide interactive responses to the issued queries. This environment is challenging for index creation, as traditional database indexes require upfront creation, hence a priori workload knowledge, to be efficient. In this paper, we introduce Progressive Indexing , a novel performance-driven indexing technique that focuses on automatic index creation while providing interactive response times to incoming queries. Its design allows queries to have a limited budget to spend on index creation. The indexing budget is automatically tuned to each query before query processing. This allows for systems to provide interactive answers to queries during index creation while being robust against various workload patterns and data distributions.

GPU rasterization for real-time spatial aggregation over arbitrary polygons

Visual exploration of spatial data relies heavily on spatial aggregation queries that slice and summarize the data over different regions. These queries comprise computationally-intensive point-in-polygon tests that associate data points to polygonal regions, challenging the responsiveness of visualization tools. This challenge is compounded by the sheer amounts of data, requiring a large number of such tests to be performed. Traditional pre-aggregation approaches are unsuitable in this setting since they fix the query constraints and support only rectangular regions. On the other hand, query constraints are defined interactively in visual analytics systems, and polygons can be of arbitrary shapes. In this paper, we convert a spatial aggregation query into a set of drawing operations on a canvas and leverage the rendering pipeline of the graphics hardware (GPU) to enable interactive response times. Our technique trades-off accuracy for response time by adjusting the canvas resolution, and can even provide accurate results when combined with a polygon index. We evaluate our technique on two large real-world data sets, exhibiting superior performance compared to index-based approaches.

Loom: Complex large-scale visual insight for large hybrid IT infrastructure management

Interactive visual exploration techniques (IVET) such as those advocated by Shneiderman and extreme scale visual analytics have successfully increased our understanding of a variety of domains that produce huge amounts of complex data. In spite of their complexity, IT infrastructures have not benefited from the application of IVET techniques.Loom is inspired in IVET techniques and builds on them to tame increasing complexity in IT infrastructure management systems guaranteeing interactive response times and integrating key elements for IT management: Relationships between managed entities coming from different IT management subsystems, alerts and actions (or reconfigurations) of the IT setup. The Loom system builds on two main pillars: (1) a multiplex graph spanning data from different ITIMs; and (2) a novel visualisation arrangement: the Loom “Thread” visualisation model.We have tested this in a number of real-world applications, showing that Loom can handle million of entities without losing information, with minimum context switching, and offering better performance than other relational/graph-based systems. This ensures interactive response times (few seconds as 90th percentile). The value of the “Thread” visualisation model is shown in a qualitative analysis of users’ experiences with Loom.

Obtaining and Managing Answer Quality for Online Data-Intensive Services

Online data-intensive (OLDI) services use anytime algorithms to compute over large amounts of data and respond quickly. Interactive response times are a priority, so OLDI services parallelize query execution across distributed software components and return best effort answers based on the data so far processed. Omitted data from slow components could lead to better answers, but tracing online how much better the answers could be is difficult. We propose Ubora, a design approach to measure the effect of slow-running components on the quality of answers. Ubora randomly samples online queries and executes them a second time. The first online execution omits data from slow components and provides interactive answers. The second execution uses mature results from intermediate components completed after the online execution finishes. Ubora uses memoization to speed up mature executions by replaying network messages exchanged between components. Our systems-level implementation works for a wide range of services, including Hadoop/Yarn, Apache Lucene, the EasyRec Recommendation Engine, and the OpenEphyra question-answering system. Ubora computes answer quality with more mature executions per second than competing approaches that do not use memoization. With Ubora, we show that answer quality is effective at guiding online admission control. While achieving the same answer quality on high-priority queries, our adaptive controller had 55% higher peak throughput on low-priority queries than a competing controller guided by the rate of timeouts.

Kodiak

Turn's online advertising campaigns produce petabytes of data. This data is composed of trillions of events, e.g. impressions, clicks, etc., spanning multiple years. In addition to a timestamp, each event includes hundreds of fields describing the user's attributes, campaign's attributes, attributes of where the ad was served, etc. Advertisers need advanced analytics to monitor their running campaigns' performance, as well as to optimize future campaigns. This involves slicing and dicing the data over tens of dimensions over arbitrary time ranges. Many of these queries need to power the web portal to provide reports and dashboards. For an interactive response time, they have to have tens of milliseconds latency. At Turn's scale of operations, no existing system was able to deliver this performance in a cost effective manner. Kodiak, a distributed analytical data platform for web-scale high-dimensional data, was built to serve this need. It relies on pre-computations to materialize thousands of views to serve these advanced queries. These views are partitioned and replicated across Kodiak's storage nodes for scalability and reliability. They are system maintained as new events arrive. At query time, the system auto-selects the most suitable view to serve each query. Kodiak has been used in production for over a year. It hosts 2490 views for over three petabytes of raw data serving over 200K queries daily. It has median and 99% query latencies of 8 ms and 252 ms respectively. Our experiments show that its query latency is 3 orders of magnitude faster than leading big data platforms on head-to-head comparisons using Turn's query workload. Moreover, Kodiak uses 4 orders of magnitude less resources to run the same workload.

Elite: an elastic infrastructure for big spatiotemporal trajectories

As the volumes of spatiotemporal trajectory data continue to grow at a rapid pace; a new generation of data management techniques is needed in order to be able to utilize these data to provide a range of data-driven services, including geographic-type services. Key challenges posed by spatiotemporal data include the massive data volumes, the high velocity with which the data are captured, the need for interactive response times, and the inherent inaccuracy of the data. We propose an infrastructure, Elite, that leverages peer-to-peer and parallel computing techniques to address these challenges. The infrastructure offers efficient, parallel update and query processing by organizing the data into a layered index structure that is logically centralized, but physically distributed among computing nodes. The infrastructure is elastic with respect to storage, meaning that it adapts to fluctuations in the storage volume, and with respect to computation, meaning that the degree of parallelism can be adapted to best match the computational requirements. Further, the infrastructure offers advanced functionality, including probabilistic simulations, for contending with the inaccuracy of the underlying data in query processing. Extensive empirical studies offer insight into properties of the infrastructure and indicate that it meets its design goals, thus enabling the effective management of big spatiotemporal data.

DROP: A Data Reduction and Organization Paradigm and its Application in Image Analysis

In this paper, we deal with the problem of the annotation process in image analysis. This problem refers to the trade-off, wherein the human knowledge is indispensable for the success of the process and human's time and effort are precious resources. Can the human annotate a minimum number of images and the classifier label the remaining ones with high accuracy? Active learning techniques have been investigated to answer this question. However, these techniques very often ignore the need for interactive response times during the active learning process. They usually adopt a common paradigm which is impractical considering large datasets. We propose an effective and efficient Data Reduction and Organization Paradigm for image analysis. In our paradigm, the proposed active learning methods should be able to reduce and/or organize the large dataset such that sample selection does not require to reprocess it entirely at each learning iteration. Moreover, it can be interrupted as soon as a desired number of samples from the reduced and organized dataset is identified. These methods show an increasing progress, first with data reduction only, and then with subsequent organization of the reduced dataset. Experimental results have demonstrated the robustness of the proposed paradigm using datasets from distinct applications and baseline approaches.

SnapToQuery

A critical challenge in the data exploration process is discovering and issuing the "right" query, especially when the space of possible queries is large. This problem of exploratory query specification is exacerbated by the use of interactive user interfaces driven by mouse, touch, or next-generation, three-dimensional, motion capture-based devices; which, are often imprecise due to jitter and sensitivity issues. In this paper, we propose SnapToQuery , a novel technique that guides users through the query space by providing interactive feedback during the query specification process by "snapping" to the user's likely intended queries. These intended queries can be derived from prior query logs, or from the data itself, using methods described in this paper. In order to provide interactive response times over large datasets, we propose two data reduction techniques when snapping to these queries. Performance experiments demonstrate that our algorithms help maintain an interactive experience while allowing for accurate guidance. User studies over three kinds of devices (mouse, touch, and motion capture) show that SnapToQuery can help users specify queries quicker and more accurately; resulting in a query specification time speedup of 1.4× for mouse and touch-based devices and 2.2× for motion capture-based devices.

Robust active learning for the diagnosis of parasites

We have developed an automated system for the diagnosis of intestinal parasites from optical microscopy images. The objects (species of parasites and impurities) segmented from these images form a large dataset. We are interested in the active learning problem of selecting a reasonably small number of objects to be labeled under an expert׳s supervision for use in training a pattern classifier. However, impurities are very numerous, constitute several clusters in the feature space, and can be quite similar to some species of parasites, leading to a significant challenge for active learning methods. We propose a technique that pre-organizes the data and then properly balances the selection of samples from all classes and uncertain samples for training. Early data organization avoids reprocessing of the large dataset at each learning iteration, enabling the halting of sample selection after a desired number of samples per iteration, yielding interactive response time. We validate our method by comparing it with state-of-the-art approaches, using a previously labeled dataset of almost 6000 objects. Moreover, we report results from experiments on a very realistic scenario, consisting of a dataset with over 140,000 unlabeled objects, under unbalanced classes, the absence of some classes, and the presence of a very large set of impurities.

DWPPT: Data Warehouse Performance Prediction Tool

The increasing demands for interactive response time from the users makes query performance one of the central problems of Data warehouse systems today. Performance is an important quality aspect of Data warehouse systems. Predicting the performance of Data warehouse systems during early design stages of their development is significant. Software Performance Engineering(SPE) promotes the idea that the integration of performance analysis into the software development process, from the earliest stages to the end, can ensure that the system will meet its performance objectives. This paper describes the features and use of a prototype tool, DWPPT(Data Warehouse Performance Prediction Tool) which is designed to analyze the performance of the Data warehouse in different environmental conditions. The tool supports SPE process for Data warehouse systems. The tool is useful for Data warehouse managers in identifying critical components, diagnosing problems and hence optimizing the overall design. Our objective is to investigate the impact of Data warehouse design factors on OLAP performance for different user populations and hardware configurations. An analytical and simulation modeling approach is used for the tool to predict performance of Data warehouse systems.