Querying Video Libraries

There is now growing interest in organizing and querying large bodies of video data. In this paper, we will develop a simple SQL-like video query language which can be used not only to identify videos in the library that are of interest to the user, but which can also be used to extract, from such a video in a video library, the relevant segments of the video that satisfy the specified query condition. We investigate various types of user requests and show how they are expressed using our query language. We also develop polynomial-time algorithms to process such queries. Furthermore, we show how video-presentations may be synthesized in response to a user query. We show how a standard relational database system can be extended in order to handle queries such as those expressed in our language. Based on these principles, we have built a prototype video retrieval system called VIQS. We will describe the design and implementation of VIQS and show some sample interactions with VIQS. (Also cross-referenced as UMIACS-TR-95-66

Presentation Planning for Distributed Video Systems

A distributed video-on-demand system is one where a collection of video data is located at dispersed sites across a computer network. In a single-site environment, a local video server retrieves video data from its local storage device (or devices). However, in the setting of a distributed VoD system, when a customer requests a movie from his/her local server, the server may need to interact with other servers located across the network. In this paper, we present three types of presentation plans, that a local server must construct in order to satisfy the customer's request. Informally speaking, a presentation plan is a detailed (temporally synchronized) sequence of steps that the host server must perform at given points in time. This involves obtaining committments from other video servers, obtaining committments from the network service provider, as well as making committments of local resources, within the limitations of available bandwidth, available buffer, and customer/client data consumption rates. The three types of plans described in this paper all work at different "levels of abstraction" in this planning process. Furthermore, we introduce two measures of how good a plan is: minimizing wait time for the customer, and minimizing a quantity called access bandwidth (which informally speaking, specifies how much network/disk bandwidth is used). We develop algorithms to compute optimal (w.r.t. the above measures) plans for all three types, and show experimentally that in all three cases, one of the three types of plans (called a hybrid presentation plan) systematically outperforms the other two. In addition to these new concepts, our framework has the advantage that many results that had previously been verified experimentally in the literature can now be conclusively proved mathematically. (Also cross-referenced as UMIACS-TR-96-91

Resource Lock Commit Protocol (RLCP) for Multimedia Object Retrieval

Many multimedia presentation applications involve retrieval of objects from more than one collaborating server. Presentations of objects from different collaborating servers might be inter-dependent. For instance, we can consider distributed video servers where blocks of movies are distributed over a set of servers. Here, blocks of a movie from different video servers have to be retrieved and presented continuously without any gaps in the presentation. Such applications first need an estimate of the available network resources to each of the collaborating server in order to identify a schedule for retrieving the objects composing the presentation. A collaborating server can suggest modifications of the retrieval schedule depending on its load. These modifications can potentially affect the retrieval schedule for other collaborating applications. Hence, a sequence of negotiations have to be carried out with the collaborating servers in order to commit for a retrieval schedule of the objects composing the multimedia presentation. In this paper, we propose an application sub-layer protocol, Resource Lock Commit Protocol (RLCP), for handling the negotiation and commitment of the resources required for a collaborative multimedia presentation application. (Also cross-referenced as UMIACS-TR-97-08

A situation-aware cross-platform architecture for ubiquitous game

Multi-player online games (MOGs) are popular in these days. However, contemporary MOGs do not really support ubiquity in the sense that a seamless service across heterogeneous hardware platforms is not provided. This paper presents the architecture of the cross-platform online game, which provides a service to users from heterogeneous platforms and is equipped with a situation-aware capability for enabling the users to seamlessly move between heterogeneous platforms. The experimental results through the prototype implementations show the feasibility of the situation-aware cross-platform game

A Two-Stage Multistep-Ahead Electricity Load Forecasting Scheme Based on LightGBM and Attention-BiLSTM

An efficient energy operation strategy for the smart grid requires accurate day-ahead electricity load forecasts with high time resolutions, such as 15 or 30 min. Most high-time resolution electricity load prediction techniques deal with a single output prediction, so their ability to cope with sudden load changes is limited. Multistep-ahead forecasting addresses this problem, but conventional multistep-ahead prediction models suffer from deterioration in prediction performance as the prediction range is expanded. In this paper, we propose a novel two-stage multistep-ahead forecasting model that combines a single-output forecasting model and a multistep-ahead forecasting model to solve the aforementioned problem. In the first stage, we perform a single-output prediction based on recent electricity load data using a light gradient boosting machine with time-series cross-validation, and feed it to the second stage. In the second stage, we construct a multistep-ahead forecasting model that applies an attention mechanism to sequence-to-sequence bidirectional long short-term memory (S2S ATT-BiLSTM). Compared to the single S2S ATT-BiLSTM model, our proposed model achieved improvements of 3.23% and 4.92% in mean absolute percentage error and normalized root mean square error, respectively

Real-time car tracking system based on surveillance videos

Abstract As a variety of video surveillance devices such as CCTV, drones, and car dashboard cameras have become popular, numerous studies have been conducted regarding the effective enforcement of security and surveillance based on video analysis. In particular, in car-related surveillance, car tracking is the most challenging task. One early approach to accomplish such a task was to analyze frames from different video sources separately. Considering the shooting range of the bulk of video devices, the outcome from the analysis of single video source is highly limited. To obtain more comprehensive information for car tacking, a set of video sources should be considered together and the relevant information should be integrated according to spatial and temporal constraints. Therefore, in this study, we propose a real-time car tracking system based on surveillance videos from diverse devices including CCTV, dashboard cameras, and drones. For scalability and fault tolerance, our system is built on a distributed processing framework and comprises a Frame Distributor, a Feature Extractor, and an Information Manager. The Frame Distributor is responsible for distributing the video frames from various devices to the processing nodes. The Feature Extractor extracts principal vehicle features such as plate number, location, and time from each frame. The Information Manager stores all the features into a database and handles user requests by collecting relevant information from the feature database. To illustrate the effectiveness of our proposed system, we implemented a prototype system and performed a number of experiments. We report some of the results