• Journal of Computing Science and Engineering
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• v.5 no.1
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• pp.85-110
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• 2011

Achieving situation awareness is especially challenging for real-time data stream applications because they i) operate on continuous unbounded streams of data, and ii) have inherent realtime requirements. In this paper we showed how formal data stream modeling and analysis can be used to better understand stream behavior, evaluate query costs, and improve application performance. We used MEDAL, a formal specification language based on Petri nets, to model the data stream queries and the quality-of-service management mechanisms of RT-STREAM, a prototype system for data stream management. MEDAL's ability to combine query logic and data admission control in one model allows us to design a single comprehensive model of the system. This model can be used to perform a large set of analyses to help improve the application's performance and quality of service.

• International Journal of Advanced Culture Technology
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• v.2 no.1
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• pp.14-19
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• 2014

In this paper, we propose a stream based patching technique in order to reduce demands of network output bandwidth required to provide the true video-on-demand (VoD) service in a Multimedia server. The proposed scheme calculates required streams to clients accurately by analyzing temporal relationships between already arrived requests in a multimedia server and still progressing streams, and then transmits streams freshly. Since our stream based patching technique induces new linking stream which is playing a link role between long and short patching streams, it reduces demand of network output bandwidth required to provide the true VoD service in a multimedia server. Accordingly, we know that the proposed scheme improves service latency and defection rate than those of existing patching technique by a simulation study.

• Journal of Korea Spatial Information System Society
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• v.9 no.1
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• pp.91-104
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• 2007

In ubiquitous computing environment, people expect services to change actively in response to the change of themselves and surrounding environment. In order to meet such expectations, the streaming service needs technologies for migrating through various devices, following the user's movement, and the technology of individualized streaming push service. In this paper, we designed and implemented U-Stream, a ubiquitous streaming service system, based on user-defined context and stream view. The system classifies contexts according to streaming service migration and allows users to define some contexts and, by doing so, provides user-oriented individualized services rather than uniform services based solely on the developers' anticipations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.2
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• pp.154-173
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• 2010

Database outsourcing is unavoidable in the near future. In the scenario of data stream outsourcing, the data owner continuously publishes the latest data and associated authentication information through a service provider. Clients may register queries to the service provider and verify the result's correctness, utilizing the additional authentication information. Research on On-line Stream Analytics (OLSA) is motivated by extending the data cube technology for higher multi-level abstraction on the low-level-abstracted data streams. Existing work on OLSA fails to consider the issue of database outsourcing, while previous work on stream authentication does not support OLSA. To close this gap and solve the problem of OLSA query authentication while outsourcing data streams, we propose MDAHRB and MDAHB, two multi-dimensional authentication approaches. They are based on the general data model for OLSA, the stream cube. First, we improve the data structure of the H-tree, which is used to store the stream cube. Then, we design and implement two authentication schemes based on the improved H-trees, the HRB- and HB-trees, in accordance with the main stream query authentication framework for database outsourcing. Along with a cost models analysis, consistent with state-of-the-art cost metrics, an experimental evaluation is performed on a real data set. It exhibits that both MDAHRB and MDAHB are feasible for authenticating OLSA queries, while MDAHRB is more scalable.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1731-1732
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• 2008

Recently, many researchers have developed various service robots, in which the position estimation and path following of mobile objects have been raised an important problem. We should know where a mobile robot so that there are many introduced localization and path following schemes. In this paper, we propose an efficient localization algorithm for the precise localization of a mobile robot with the glaser stream sensor. We use the glaser stream sensor for following a given path in indoor environments. Since the glaser stream sensor utilizes precise optical motion estimation technology, we can achieve high speed motion detection and high resolution. The experimental results show that the glaser stream sensor may be a good sensor for many indoor service robots.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.46-56
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• 2008

Double Patching is a multicasting technique for a VoD system which has been proposed to provide a true VoD service by making clients share a long patching stream as well as a regular stream For subsequent short patching streams, the technique always makes the long patching stream have extra data that will be played back during a double period of a patching window. In this paper, we propose a technique, using the start time of the latest short patching stream, optimizes Double Patching by deleting the useless data included in the long patching stream when the patching window of the long patching stream closes. The mean requirement for the server's bandwidth to provide the true VoD service is used as a performance metric, and the effect of the request inter-arrival time, the size of the client's local buffer and the video length on the mean bandwidth requirement is evaluated. Performance evaluation result shows that the proposed technique optimizes Double Patching in all cases.

• Journal of Information Processing Systems
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• v.19 no.4
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• pp.439-449
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• 2023

This paper deals with a resource efficient artificial intelligence (AI) service architecture for multi-channel video streams. As an AI service, we consider the object detection model, which is the most representative for video applications. Since most object detection models are basically designed for a single channel video stream, the utilization of the additional resource for multi-channel video stream processing is inevitable. Therefore, we propose a resource efficient AI service framework, which can be associated with various AI service models. Our framework is designed based on the modular architecture, which consists of adaptive frame control (AFC) Manager, multiplexer (MUX), adaptive channel selector (ACS), and YOLO interface units. In order to run only a single YOLO process without regard to the number of channels, we propose a novel approach efficiently dealing with multi-channel input streams. Through the experiment, it is shown that the framework is capable of performing object detection service with minimum resource utilization even in the circumstance of multi-channel streams. In addition, each service can be guaranteed within a deadline.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.364-367
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• 2009

This paper presents a scheme that generates a caption file by extracting a Closed Caption stream from DTV signal. Note that Closed-Captioning service helps to bridge "digital divide" through extending broadcasting accessibility of a neglected class such as hearing-impaired person and foreigner. In Korea, DTV Closed Captioning standard was developed in June 2007, and Closed Captioning service should be supported by an enforcing law in all broadcasting services in 2008. In this paper, we describe the method of extracting a caption data from MPEG-2 Transport Stream of ATSC-based digital TV signal and generating a caption file (SAMI and SRT) using the extracted caption data and time information. Experimental results verify the feasibility of a generated caption file using a PC-based media player which is widely used in multimedia service.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.95-103
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• 2022

As 5G mobile communication services gradually expand in P2P (peer-to-peer) or D2D (device-to-device) applications, traffic-oriented stream control such as YouTube streaming is emerging as an important technology. In D2D communication, the type of data stream most frequently transmitted by users is a video stream, which has the characteristics of a large-capacity transport stream. In a D2D communication environment, this type of stream not only provides a cause of traffic congestion, but also degrades the quality of service between D2D User Equipments (DUEs). In this paper, we propose a Traffic-Oriented Stream Scheduling (TOSS) scheme to minimize the interruption of dynamic media streams such as video streams and to optimize streaming service quality. The proposed scheme schedules the media stream by analyzing the characteristics of the media stream and the traffic type in the bandwidth of 3.5 GHz and 28 GHz under the 5G gNB environment. We examine the performance of the proposed scheme through simulation, and the simulation results show that the proposed scheme has better performance than other comparative methods.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.287-292
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• 2001

Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.