• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.19-25
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• 2010

In this paper, the performance of the DoS information security algorithm is evaluated to provide the multimedia traffic between the nodes using the multicasting services. The essence technology for information security to distribute the multimedia contents is presented. Under the multicasting services, a node participating new group needs a new address and the node compares the collision with the existing nodes, then DoS attack can be occurred between the nodes by a malicious node. Using the NS2 simulator, the number of DoS attacks, the average number of trials to generate new address, and the average time to create address are analyzed. From simulation results, the efficient algorithm with relevant random number design according to the DRM network is needed to provide secure multimedia contents distribution.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11
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• pp.3534-3543
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• 2000

We believe in terins of information service systems that one of the best ways to develop a large scale database service system is to integrate the service capability of the Web and the dta management facility of database management systems in a complementary fashion. In such integation a database gateway in the core component, the web-database gateway accesses database management systems to serve the requests represented by using the Web technology. We designd BADA/Web be independent from the Web and DBMS and much as possible, which minrrizes the performance overhead caused by connecting database management systems and makes BADA/Web portable. BADA/Web incorporates TCL into a ibrary of it and handles concurrent requests efficiently. In this paper we describe our desingn and implementation experience in integrating the Web and BADA-III We evaluate the performance of BADA/Web by measuring and companing the latency and average response time for a simple query and also explore the effects of BADA/Web with some synthetie queries .

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.40-57
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• 2015

IoT is the foundation technology that the things share the information through connected with Internet to provide service based on these information. It is applied to various fields such as personal, public and industry. Therefore, the service development is required to meet the requirement of the various service environments. The IoT service environment will be developed as the participation IoT service environment which increase the value and efficiency such as the Broadcasting and web services changed from the service provider environment to the user participation service. The user can directly reflect their requirements using the user participation IoT service environment. So, the types of IoT services will diverse and accelerate the spread of IoT service. In this paper, we derive the IoT service element through the analysis of various service scenarios, and propose the participation IoT service model and modeling mechanism. It provides the sequential service model and the relation based service model according to the service modeling proficiency of user. The proposed environment provides the web-based user interface that is implemented by the participation IoT service brokering platform.

• Spatial Information Research
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• v.17 no.4
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• pp.405-416
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• 2009

According to the changes of the city's paradigm, the demand on u-City increases rapidly. u-City has been built at 54 areas in Korea (as of May 2009). One of the important determinants of success or failure in the increasing of u-City is how to provide u-Services. Most current u-Services are Sensor Network-based monitoring services to manage urban infrastructure. u-GIS is one of fundamental requirements to implement 'any time and any where' u-Service which covers the essential meaningful term "ubiquitous". Hence, in this paper, we 1) describe the definition of the spatial awareness, 2) discuss how to converge (Spatial Embedding) among different spatial data : topographic spatial data, sensor spatial data, and more, 3) bring forth an advanced form of u-Service, 4) analyze the state-of-the-art u-GIS techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.137-143
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• 2009

Through the development of techniques, robots are becomes smaller, and many of robots needed for application are greater and greater. Method of coordinating large number of autonomous robots through local interactions has becoming an important research issue in robot community. Swarm Robot System is a system that independent autonomous robots in the restricted environment infer their status from preassigned conditions and operate their jobs through the coorperation with each other. Within the SRS,a robot contains sensor part to percept the situation around them, communication part to exchange information, and actuator part to do a work. Specially, in order to cooperate with other robots, communicating with other robot is one of the essential elements. In such as Bluetooth has many adventages such as low power consumption, small size module package, and various standard procotols, it is rated as one of the efficent communcating system for autonomous robot is developed in this paper. and How to construct and what kind of procedure to develop the communicatry system for group behavior of the SRS under intelligent space is discussed in this paper.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.47-74
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• 2007

This research purpose to improve the qualification items for electronic commerce manager. Former qualification system for the electronic commerce manager was executed 11 times from year 2000 to 2005. To improve the standard for test questions and contents of qualification items, we reviewed literatures about job analysis for electronic commerce manager, electronic commerce curriculum, e-Business market and other countries' similar qualification systems and items. We also analysed the job related knowledge, skill, and abilities using job analysis by DACUM method, subject matter experts interview and workshop committee for development and validation of qualification items. Based on the results of job analysis and DACUM workshop, we derived a job model for electronic commerce manager and then validated it through field survey and additional expert review. Finally we developed and suggested an alternated qualification items using matrix analysis between categorized job knowledge and job tasks.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.25-28
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• 2008

Currently, the prefabricated bridge having the effects to reduce the term of works and the cost of construction is often studied and countries such as America have already developed members, the parts of it, and the technique of construction. In addition, they have supplied them to the fields. The study of prefabricated method of steel composite bridge, which has the precast deck - plate and main girder fixed by high tension bolt and can resist horizontal sheer, is being progressed. However, it is difficult to understand the characteristics of the prefabricated bridge's behavior when the superstructure of the prefabricated method is analyzed by applying to the analysis model of existing bridges. Therefore, this study has the purpose of understanding real structural behavior of prefabricated bridge through comparison and analysis between the structural analysis model reflecting the characteristics of the real prefabricated bridge's superstructure and real size experiment.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.737-745
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• 2008

Recent developments of process and measurement technology bring much interest to the online monitoring of process operations such as milling, grinding, broaching, etc. The objective of online monitoring systems is to detect process changes as early as possible. This is helpful in protecting facilities against unexpected failures and then preventing unnecessary loss. This paper investigates, when the process monitoring data are obtained as a profile, the monitoring performances of a statistical $T^2$-statistic and a feedforward neural network by using a wavelet transform. Numerical experiments using cutting force data presented by Axinte show that the proposed wavelet based $T^2$-test has an acceptable power in detecting profile changes. However, its operating characteristic is very sensitive to autocorrelation. On the contrary, compared with $T^2$-test, the neural network has more stable performance in the presence of autocorrelation. This indicates that an adaptive feature to analyze noises should be incorporated into the wavelet based $T^2$-test.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.941-944
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• 2008

Various ductile fiber reinforced cement composite(DFRCC) including large quantities of PVA fiber or steel fiber have been developed recently and studies to find applications in diverse domains are currently conducted actively. Regard to economical efficiency, DFRCC becomes competitive when applied as special elements and repair material with small quantities rather than the casting of large volume for the main body of structures in field. The authors have developed FRP-DFRCC composite slab for bridges and a wet spraying repair technique using DFRCC. In case of the application on FRP-DFRCC composite slab, it was found that there was no problems the structure and durability of it after passed 3 months. And in case of the application on the application of the deteriorated sewage box that passed 20 years, it was found that there was no difference the repair performance between domestic PVA fiber and the Japan. Therefore, DFRCC using PVA fiber, the concrete structures can be increased to performance and secured the economical efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1589-1598
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• 2014

To support the WBAN, IEEE 802.15 Task Group 6 announced standardized documents on technical requirements of the PHY and MAC. In the IEEE 802.15.6 MAC protocol, CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) algorithm is performed based on the eight-level priorities according to the type of traffics of the periodic data from medical sensor nodes. Several nodes, which detected the changed bio signals, transmit emergency data at the same time, so latency could be higher than emergency latency and energy consumption will increase. In this thesis, we proposed a CSMA/CA algorithm in WBAN to solve these problems. Simulations are performed using a Castalia based on the OMNeT++ network simulation framework to estimate the performance of the proposed superframe and algorithms. Performance evaluation results show that the packet transmission success rate and energy efficiency are improved by reducing the probability of collision using the proposed MAC protocol.