• Journal of KIISE
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• v.43 no.10
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• pp.1165-1172
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• 2016

In cloud storage environment, deduplication enables efficient use of the storage. Also, in order to save network bandwidth, cloud storage service provider has introduced client-side deduplication. Cloud storage service users want to upload encrypted data to ensure confidentiality. However, common encryption method cannot be combined with deduplication, because each user uses a different private key. Also, client-side deduplication can be vulnerable to security threats because file tag replaces the entire file. Recently, proof of ownership schemes have suggested to remedy the vulnerabilities of client-side deduplication. Nevertheless, client-side deduplication over encrypted data still causes problems in efficiency and security. In this paper, we propose a secure and practical client-side encrypted data deduplication scheme that has resilience to brute force attack and performs proof of ownership over encrypted data.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.68-79
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• 2005

The popularity of Web service is ever increasing. As the number of services and clients continue to increase, the problem of providing a system that scales with this increase is becoming more difficult. A costly and ineffective method is to buy a new system that is more powerful every time the load becomes unbearable. h more cost effective solution is to expand the system as the need arises. This is the approach taken in Web cluster systems. However, providing effective scalability in a Web cluster system is stil1 an open issue. In this study, we implement a Web cluster system based on Layer 7 switching technique on Linux. The implementation is based on a design proposed and implemented by Aron et al., but on the FreeBSD. Though the design li the same, due to the vast difference between the FreeBSD and Linux, the implementation presented in this paper is totally new. We also propose the Dual Scheduling (DS) load distribution algorithm that distributes the requests to the system resources by observing the variations in the request rate. We show through measurement on our implementation that the DS alorithm performs considerably bettor than previous algorithms.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.120-129
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• 2011

This research aims to investigate the representative affective words and the structure among them to scrutinize user's affect revealed in the ride film based on three dimension stereoscopic image. Previous studies related to the affect were reviewed and the affect words well-suited for three dimension stereoscopic image were collected. Suitability test for two hundred six basic affect words gathered as the result was done from sixty two typical users and four experts. Seventy seven candidate affect words have been selected and by the exclusion of similarity among them, finally twenty six words were extracted from the reduction process. Consequently fifteen representative words and the structure as the network between each word were revealed by using free association test based on twenty six affect words. We propose the affect research including sensors, emotions, and affects related to moving image rather than still mage during doing research affects in most of the previous studies. The future work includes the affect space and the affect effect for ride film based on three dimension stereoscopic image. This study can be adopted practically in the production of ride films and provided with a basic design guideline.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.2
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• pp.212-217
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• 2011

In this paper, we developed an intelligent minimized integrated digital public address which can provide context awareness of various events occurring in future intelligent buildings. It is able to recognize both voices and sounds, such as a fire bell and a disaster bell, which signal to escape in emergence situations and it can sense information which is sent from various sensors, for example, the inner temperature, humidity, and environment status in an intelligent building. Also, the intelligent digital integrated public address can broadcast information to individual places, according to context awareness that is from sensing information, by using network with an ID. And we are developing a minimized integrated digital public address system that has facilities such as external input, Mic., CD, MP3 and Radio. Developing an integrated digital public address system with operational MICOM will make it possible to control the facilities of digital devices centrally. The operational MICOM is composed of 3 layers which are a control layer, a processing layer and a user interface layer.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.28-38
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• 2009

Login process uses both ID and password information to authenticate someone and to permit its access privilege on system. However, an attacker can get those ID and password information by using existing packet sniffing or key logger programs. It cause privacy problem as those information can be used as a hacking and network attack on web server and web e-mail system. Therefore, a more secure and advanced authentication mechanism should be required to enhance the authentication process on existing system. In this paper, we propose a multi-factor authentication process by using software form of secure card system combined with existing ID/Password based login system. Proposed mechanism uses a random number generated from the his/her own handset with biometric information. Therefore, we can provide a one-time password function on web login system to authenticate the user using multi-factor form. Proposed scheme provide enhanced authentication function and security because it is a 'multi-factor authentication mechanism' combined with handset and biometric information on web login system.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.97-99
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• 1992

After development of order communication system for out-patients using PC and LAN in May 1992, this system had been tested for 2 months. The system also use Host computer(IBM 9221-170) as a data bank and communicats wi th emulation card(3270 emulator. Interlink Inc., Korea). Since September 1992, this system(named YOUSEI-PC) has been running successfully in the Yonsei Cardiovascular Center of the Severance Hospital, Yonsei University College of Medicine. After introducing this system, it enables patients to receive drugs wi thin 30 minutes after prescription and revealed effective system not to reduce waiting time for the patients but also to remove charge-troubling(due to mis-entry of prescription). This system also seems to be effective in terms of office automatism for hospital management. However users, usually physitions, required more friendly and easy system to operate and we thought that the most important one to successfully introduce order communication computer system in the hospital is user interface.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.353-356
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• 2007

With advances in sensor technology, current researches on the pertinent techniques are actively directed toward the way which enables the USN computing service. For many applications using sensor networks, the incoming data are by nature characterized as high-speed, continuous, real-time and infinite. Due to such uniqueness of sensor data characteristics, for some instances a finite-sized buffer may not accommodate the entire incoming data, which leads to inevitable loss of data, and requirement for fast processing makes it impossible to conduct a thorough investigation of data. In addition to the potential problem of loss of data, incoming data in its raw form may exhibit high degree of complexity which evades simple query or alerting services for capturing and extracting useful information. Furthermore, as traditional mining techniques are developed to handle fixed, static historical data, they are not useful and directly applicable for analyzing the sensor data. In this paper, (1) describe how three mining techniques (sensor data outlier analysis, sensor pattern analysis, and sensor data prediction analysis) are appropriate for the USN middleware structure, with their application to the stream data in ocean environment. (2) Another proposal is a middleware structure based on USN environment adaptive to above mining techniques. This middleware structure includes sensor nodes, sensor network common interface, sensor data processor, sensor query processor, database, sensor data mining engine, user interface and so on.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.441-450
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• 2006

WiBro(Portable Internet Service) is service being capable to provide a high data rate wireless internet access with Personal Subscriber Station under the stationary or mobile environment, anytime and any where. It will fill the gap between very high data rate wireless local area networks and very high mobility cellular systems. The security is an important point of WiBro providing high data and mobile wireless services. This paper proposes user authentication mechanism of WiBro wireless networks applied EAP-AKA authentication protocol. As a result of Wireless authentication based on EAP-AKA, this mechanism is capable to be used in WiBro-WLAN-3GPP interworking scenario as well as the WiBro authentication mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1390-1406
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• 1994

This study deals with the DMCLP(Delay constrained Minimum Cost Loop Problem)-one of problems arising in the design of local access computer networks. The problem consists of finding a set of rings to satisfy the traffic requirements of end user terminals. In the problem, the objective is to minimize the total link cost. This paper presents heuristic algorithm which consists of two phases for this problem, under the constraints that the number of nodes served by a single ring is limited and network mean delay is dropped within the desired time. The algorithm is derived using the clusters obtained by the existing MCLP(Minimum Cost Loop Problem) algorithm and a trade-off criterion explained in the paper. Actually, simulation results in that the proposed algorithm in this paper produces better solution than the existing MCLP algorithm modified. In addition, the algorithm has the relatively short running time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.883-890
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• 2006

The study of sensor network database is beginning to liven up as we are interested in Ubiquitous Computing technology in hardware, communication, database and so on. Especially, as new smart sensors have capabilities of real-time information gathering and analysis of each sensor node, data processing becomes an important issue in Ubiquitous Computing. In thesis, we have applied TinyDB(query processing system) to carry sensor node with line tracer which can follow the fixed path. After we gathered data around path, we have processed data in TinyDB GUI, gathered data, displayed data on a web server. Also we have a web browser on an embedded board for convenient user interface and implemented touch screen such that users can operate with a finger.