• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.3
• /
• pp.576-585
• /
• 2014

Collecting and utilizing have a huge amount of personal data have caused severe security issues such as leakage of personal information. Several encryption algorithms for collected personal information have been widely adopted to prevent such problems. In this paper, a novel algorithm based on MapReduce is proposed for encrypting such private information. Furthermore, test environment has been built for the performance verification of the distributed encryption processing method. As the result of the test, average time efficiency has improved to 15.3% compare to encryption processing of token server and 3.13% compare to parallel processing.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.11
• /
• pp.2678-2684
• /
• 2014

In this paper a new message control method that can reduce server load and network traffic in XMPP/SIP presence service system has been proposed. This presence service system can process both XMPP(Extensible Massaging and Presence Protocol) based presence information and SIP(Session Initiation Protocol) based presence information. A new XMPP stanza architecture with added elements for presence stanza and IQ stanza has been designed, and a new presence information data processing method which can reduce size of SIP notification message and SIP PUBLISH message has been suggested. Furthermore a messages exchanging procedure that can transfer presence information between XMPP domain and SIP domain has been also suggested. The performance of the proposed system has been analysed by simulation.

• Journal of KIISE:Databases
• /
• v.31 no.3
• /
• pp.243-251
• /
• 2004

Most programs of bioinformatics provide biochemists and biologists retrieve and analysis services of gene and protein database. As these services retrieve database for each arrival of user's request, it takes a long time and increases server's load and response time. In this paper. by utilizing database retrieval patterns of sequence alignment programs in bioinformatics, grouping method is proposed to share database retrieval between many requests. Carpool method is also proposed to reduce response time as well as to increase system expandability by combining new arriving requests with the previous on going requests. The performance of our two proposed schemes is verified by mathematic analysis and simulation.

• Journal of KIISE:Computer Systems and Theory
• /
• v.34 no.4
• /
• pp.138-144
• /
• 2007

With recent proliferation of video-on-demand services, caching in a multimedia streaming server is becoming increasingly important. Previous studies have shown that request interval based caching and its extension for considering different video popularity performs well in various streaming environments. In this paper, we show that block level refinement of this existing scheme can further improve the performance of streaming servers. Trace driven simulations with real world VOD traces have shown that the proposed scheme improves the cache hit rate and the startup latency.

• Journal of Internet Computing and Services
• /
• v.4 no.5
• /
• pp.87-96
• /
• 2003

The additional mechanism is required to set up a secure connection among the communication subjects in the internet environment. Each entity should transfer and receive the encrypted and hashed data to guarantee the data integrity. Also, the mutual authentication procedure should be processed using a secure communication protocol. Although the OpenSSL which implements the TLS is using by many developers and its stability and performance are proved, it has a difficulty in using because of its large size. So, this paper designs and implements the secure communication which the users can use easily by modification works of OpenSSL library API. We proved the real application results using the client/server case which supports a secure communication using the implemented API.

• Journal of the Korea Computer Industry Society
• /
• v.7 no.3
• /
• pp.217-226
• /
• 2006

Intensive studies have been made in the area of N-VOD server Multimedia files in the N-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 VCR-LIKE operations and buffer, disk scheduling policy for multimedia services with management of VOD sever resources. Simulation results show that the rate of buffer usage and service time of proposed scheme are about 18% performance improved than that of traditional methods. This implies that our method can allow much more users for given resources.

• Journal of KIISE
• /
• v.42 no.8
• /
• pp.990-997
• /
• 2015

Panoramic image creation has been extensively studied. Existing methods use customized hardware, or apply post-processing methods to seamlessly stitch images. These result in an increase in either cost or complexity. In addition, images can only be stitched under certain conditions such as existence of characteristic points of the images. This paper proposes a low cost and easy-to-use system that produces realtime panoramic video. We use an off-the-shelf embedded platform to capture multiple images, and these are then transmitted to a server in a compressed format to be merged into a single panoramic video. Finally, we analyze the performance of the implemented system by measuring time to successfully create the panoramic image.

• Korean Journal of Remote Sensing
• /
• v.24 no.5
• /
• pp.389-396
• /
• 2008

In these days, various kinds of web applications based on web 2.0 paradigm have been developed. In web 2.0 paradigm pursuing participation, sharing, and openness on the web-as-platform, web mapping or web GIS application are regarded as top most applications, so that web applications, handling geo-spatial contents, with user-interaction interface and search engine of high performance have been provided for both public users and expert users in the special domains. Public and industrial needs for web mapping mashup application by open API, linked with the practical web computing technologies, are gradually increasing. In this study, a user interface in mashup for geo-spatial feature generation was implemented by using mainly Google maps API. Spatial database resources in this implementation are those of Google mapping server. As the results, public users on web client can create their own geo-spatial data sets in web vector formats, without the help of any GIS tools or access to proprietary databases. It is concluded that web-based mashup application in client-side using open API can be used as an alternative for geo-browsing system or portable feature generation system.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.10
• /
• pp.239-244
• /
• 2019

In recent mobile environments, query processing costs have been rapidly increasing as users request large amounts of queries. In addition, the server's performance is increasing for many users to handle high-capacity queries, but the workload is increasing continuously. To solve these problems, we use the wireless broadcasting environment. However, in a existing wireless broadcasting environment, servers have a problem sending all the objects they manage to their clients. Therefore, we propose a new R-Bcast combining the advantages of demand-based and wireless broadcasting. R-Bcast is a technique that protects query information and reduces query processing time. Experiments have proved that R-Bcast is superior to conventional techniques.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.87-90
• /
• 2009

Wireless Mesh Network(WMN) is wireless backbone networks technique which has ease of network configuration and cost of advantage. Recently, WNM released a new product, but most of existing research and technology analysis the performance through the simulation. This paper build the wireless mesh network testbed for actual situation. Testbed supports multi-channel multi-interface using bridge, the Wireless Distribution System and dynamic location-based routing protocol. This routing protocol strongly design against wireless interference using metric for link channel change and real distance. Then, the address of mesh clients assigned by the centralized address management server. Mesh clients is designed and implemented to manage network through Simple Network Management Protocol.