• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.500-504
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• 2013

In this paper, we have developed the application of a remote multi-lingual video guide that allows interaction with Set Top Box of a thin client by using the WebRTC, an web browser-based communication method. A server accesses a web camera in conjunction with digital information display of a thin client connected remotely and is exchanged guide information with user. This server can be played in thin client STB using virtualization based the high-quality video compression technology. Further, it is not dependent on the performance of the STB and provides a video guide remotely.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.270-274
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• 2002

This paper presents a teleoperation system that combines computer network and an autonomous mobile robot. We control remotely an autonomous mobile robot with vision over the Internet to guide it under unknown environments in the real time. The main feature of this system is that local operators need a web browser and a computer connected to the communication network and so they can command the robot in a remote location through the home page. The hardware architecture of this system consists of an autonomous mobile robot, workstation, and local computers. The software architecture of this system includes the client part for the user interface and robot control as well as the server part for communication between users and robot. The server and client systems are developed using Java language which is suitable to internet application and supports multi-platform. Furthermore. this system offers an image compression method using JPEG concept which reduces large time delay that occurs in network during image transmission.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.34-41
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• 2008

Existing mobility support scheme like MIPv4 has the delay at data transfer and Triangle routing problem. This paper proposes the new mobility support scheme and method that can overcome the problem using MPLS LSP in Next Generation Network. The proposed scheme overcomes the problem by introducing the LMS(Location Management Server) managing the location of the mobile terminal and the MPLS LSP between FA for a tunneling. We shows on the mathematical analysis using the queuing theory that this proposed scheme is more superior to the existing method(MIP).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.818-825
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• 2004

High availability means Service-technology that can provide any solution when occur a problem in relation to hardware, software, network etc. We are in the times that the network computing service are essential to our daily life. So the importance of the high availability is being higher and higher in this social change such as the arrival of information anger times, e-commerce the extension of multi-media service etc. In this thesis, I analyzed about High-availability Linux Server for Multimedia Tourism Information System, and I proposed an alternative plan which related with its result.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1189-1202
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• 1999

As compared with VOD data, NOD article data has the following characteristics: it is created at any time, has a short life cycle, is selected as not one article but several articles by a user, and has high access locality in time. Because of these intrinsic features, user access patterns of NOD article data are different from those of VOD. Thus, building NOD system using the existing techniques of VOD system leads to poor performance. In this paper, we analysis the log file of a currently running electronic newspaper, show that the popularity distribution of NOD articles is different from Zipf distribution of VOD data, and suggest a new popularity model of NOD article data MS-Zipf(Multi-Selection Zipf) distribution and its approximate solution. Also we present a life cycle model of NOD article data, which shows changes of popularity over time. Using this life cycle model, we develop LLBF (Largest Life-cycle Based Frequency) prefetching algorithm and analysis he performance by simulation. The developed LLBF algorithm supports the similar level in hit-ratio to the other prefetching algorithms such as LRU(Least Recently Used) etc, while decreasing the number of data replacement in article prefetching and reducing the overhead of the prefetching in system performance. Using the accurate user access patterns of NOD article data, we could analysis correctly the performance of NOD server system and develop the efficient policies in the implementation of NOD server system.

• The KIPS Transactions:PartB
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• v.12B no.2 s.98
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• pp.167-172
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• 2005

A rapid growth in the number of Internet users and in massive media contents tends to cause server overload and high network traffic. As a consequence, it can be safely assumed that the quality of service is on the brink of deterioration. A solution of this problem is the development of the Content Distribution Network. Therefore, in this paper, we propose a transmission model using CDN. This model uses regional media server which closes to client, and uses MDC coding and multi-channel to reduce packet loss and delay. In conclusion, this study improved performance of multimedia service by reducing packet loss and delay.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.379-390
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• 2005

Intensive studies have been made in the area of VOD server Multimedia files in the VOD sever are characterized with the large volume of data, the requirements of synchronization and real-time playback of streams. The basic goal of the study is to find an efficient mechanism to allow maximum number of users under the limited resources such as Buffer size and disk bandwidth. we propose a efficient $pre\_fetching$ policy for multimedia services with dynamic monitoring and management of VOD sever resources. Simulation results show that the rate of buffer usage and service time of proposed scheme are about $28\%$ performance improved than that of traditional methods. This implies that our method can allow much more users for given resources.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.4
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• pp.153-161
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• 2021

Real-time access is required to handle continuous and unstructured data and should be flexible in management under dynamic state. Platform can be built to allow data collection, storage, and processing from local-server or multi-server. Although the former centralize method is easy to control, it creates an overload problem because it proceeds all the processing in one unit, and the latter distributed method performs parallel processing, so it is fast to respond and can easily scale system capacity, but the design is complex. This paper provides data collection and processing on one platform to derive significant insights from various data held by an enterprise or agency in the latter manner, which is intuitively available on dashboards and utilizes Spark to improve distributed processing performance. All service utilize dockers to distribute and management. The data used in this study was 100% collected from Kafka, showing that when the file size is 4.4 gigabytes, the data processing speed in spark cluster mode is 2 minute 15 seconds, about 3 minutes 19 seconds faster than the local mode.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3043-3067
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• 2022

With the mobile traffic in the network increases exponentially, multi-access edge computing (MEC) develops rapidly. MEC servers are deployed geo-distribution, which serve many mobile terminals locally to improve users' QoE (Quality of Experience). When the cache space of a MEC server is full, how to replace the cached videos is an important problem. The problem is also called the cache replacement problem, which becomes more complex due to the dynamic video popularity and the varied video sizes. Therefore, we proposed a new cache replacement scheme based on local video popularity and video size to solve the cache replacement problem of MEC servers. First, we built a local video popularity model, which is composed of a popularity rise model and a popularity attenuation model. Furthermore, the popularity attenuation model incorporates a frequency-dependent attenuation model and a frequency-independent attenuation model. Second, we formulated a utility based on local video popularity and video size. Moreover, the weights of local video popularity and video size were quantitatively analyzed by using the information entropy. Finally, we conducted extensive simulation experiments based on the proposed scheme and some compared schemes. The simulation results showed that our proposed scheme performs better than the compared schemes in terms of hit rate, average delay, and server load under different network configurations.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.9
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• pp.377-384
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• 2015

In this paper we propose a visualization tool for distortion-free time-series matching. Supporting distortion-free is a very important factor in time-series matching to get more accurate matching results. In this paper, we visualize the result of time-series matching, which removes various time-series distortions such as noise, offset translation, amplitude scaling, and linear trend by using moving average, normalization, linear detrending transformations, respectively. The proposed visualization tool works as a client-server model. The client sends a user-selected time-series, of which distortions are removed, to the server and visualizes the matching results. The server efficiently performs the distortion-free time-series matching on the multi-dimensional R*-tree index. By visualizing the matching result as five different charts, we can more easily and more intuitively understand the matching result.