• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2109-2116
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• 2014

This paper presents the implementation and design of the advanced WI-FI systems with beam-forming antenna that radiate their power to the direction of user equipment to improve the overall throughput, contrast to the general WI-FI systems equipped with omni-antenna. The system consists of patch array antenna, DSP, FPGA, and Qualcomm's commercial chip. The beam-forming system on the FPGA utilizes the packet information from Qualcomm's commercial chip to control the phase shifters and attenuators of the patch array antenna. The PCI express interface has been used to maximize the communication speed between DSP and FPGA. The directions of arrival of users are managed using the database, and each user is distinguished by the MAC address given from the packet information. When the system wants to transmit a packet to one user, it forms beams to the direction of arrival of the corresponding user stored in the database to maximize the throughput. Directions of arrival of users are estimated using the received preamble in the packet to make its SINR as high as possible. The proposed beam-forming system was implemented using an FPGA and Qualcommm's commercial chip together. The implemented system showed considerable throughput improvement over the existing general AP system with omni-directional antenna in the multi-user communication environment.

• Journal of the Korea Society of Computer and Information
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• v.10 no.6 s.38
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• pp.219-226
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• 2005

This paper describes the open API with integration of semantic web service with PARLAY X based open API in 4G mobile network. It can be expected that the intelligence such as the context-awareness, adaptation and personalization in 4G mobile network will be deployed. But the existing PARLAY based network lacks in considering context-awareness, adaptation and personalization. Therefore, the object of this paper is to support the architecture and the Application Programming Interface (API) of the network service for the context-awareness, adaptation and Personalization in 4G mobile network The open API is to provide users with the adaptive network service to the changing context constraints as well as detecting the changing context and user's Preference. For instance, the open API can Provide users with QoS in network according to the detected context and user's preference, after detecting the context such as location and speed and user's preference.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.117-124
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• 2004

In this paper, we have been implemented the QPSK-based underwater transmission systems using DSP in order to transmit the underwater image data. We have adopted a BDPA (Block Data Parallel Architecture) to control multiple DSPs used in the transmitter and receiver in order to transmit the image data in real-time. We also have developed GUI software in order to drive and to debug the implemanted system in real-time. We have executed open sea tests in order to analyze the performance of the implemented system at East Sea near Kosung in Kangwon-Do. As a result of these experiments, it has been demonstrated that 10 kbps image data can be received without errors at 30m and 80m depth points, while the distance between the transmitter and the receiver is up to 20m.

• Korean Journal of Cognitive Science
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• v.6 no.2
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• pp.47-79
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• 1995

Since the early age of computer graphics, facial animation has been applied to various fields, and nowadays it has found several novel applications such as virtual reality(for representing virtual agents), teleconference, and man-machine interface.When we want to apply facial animation to the system with multiple participants connected via network, it is hard to animate facial expression as we desire in real-time because of the size of information to maintain an efficient communication.This paper's major contribution is to adapt 'Level-of-Detail'to the facial animation in order to solve the above problem.Level-of-Detail has been studied in the field of computer graphics to reperesent the appearance of complicated objects in efficient and adaptive way, but until now no attempt has mode in the field of facial animation. In this paper, we present a systematic scheme which enables this kind of adaptive control using Level-of-Detail.The implemented system can generate speech synchronized facial expressions with various types of user input such as text, voice, GUI, head motion, etc.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.360-370
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• 2004

Adaptive mesh refinement(AMR) is one of the popular computational simulation techniques used in various scientific and engineering fields. Although AMR data is organized in a hierarchical multi-resolution data structure, traditional volume visualization algorithms such as ray-casting and splatting cannot handle the form without converting it to a sophisticated data structure. In this paper, we present a hierarchical multi-resolution splatting technique using k-d trees and octrees for AMR data that is suitable for implementation on the latest consumer PC graphics hardware. We describe a graphical user interface to set transfer function and viewing / rendering parameters interactively. Experimental results obtained on a general purpose PC equipped with an nVIDIA GeForce3 card are presented to demonstrate that the proposed techniques can interactively render AMR data(over 20 frames per second). Our scheme can easily be applied to parallel rendering of time-varying AMR data.

• The Journal of Korean Association of Computer Education
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• v.6 no.1
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• pp.87-94
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• 2003

Recently there are many tries and researches for using web agent in education. The agent is a computer program as a common name which takes a role like a proxy or a middle ware for accomplishing the given something on behalf of user. Lately the agent is being used in the various fields. The teaching and learning is the one of those. It is the web agent that support the teaching and learning on the web. It has a concept of the program or the engine is able to do teachers roles on the behalf of him on the web. Not only the web agent is able to do teachers roles on the behalf of him, but also it is a helper that helps learners on the web. The web based teaching and learning environment has the web agent offers the personal and the adaptive information, interface, or contents.

• Steel and Composite Structures
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• v.44 no.1
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• pp.49-63
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• 2022

This study aims to develop ensemble machine learning (ML) models for estimating the peak floor acceleration and maximum top drift of steel moment frames. For this purpose, random forest, adaptive boosting, gradient boosting regression tree (GBRT), and extreme gradient boosting (XGBoost) models were considered. A total of 621 steel moment frames were analyzed under 240 ground motions using OpenSees software to generate the dataset for ML models. From the results, the GBRT and XGBoost models exhibited the highest performance for predicting peak floor acceleration and maximum top drift, respectively. The significance of each input variable on the prediction was examined using the best-performing models and Shapley additive explanations approach (SHAP). It turned out that the peak ground acceleration had the most significant impact on the peak floor acceleration prediction. Meanwhile, the spectral accelerations at 1 and 2 s had the most considerable influence on the maximum top drift prediction. Finally, a graphical user interface module was created that places a pioneering step for the application of ML to estimate the seismic demands of building structures in practical design.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.143-152
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• 2010

Because of a rising in the standard of living and the development of medical technology, Korea is expected to become an aging society more than 14% elderly population and the silver generation will be responsible for the large portion of economic activities. The silver generation has relatively diminished in perception, learning, and exercise due to the physical aging. Therefore, it is important the development of game contents which can constantly provide the maintenance function of physical and mental health and the functional exercise with spending the leisure time. In this paper, we suggest a design method for developing the game contents which are able to help the silver generation to strengthen their lower extremities and to enjoy their leisure time. The proposed method will enable to lead the silver generation to carry on the physical activities with the amusement of playing a game through the functional design concepts appropriate for the ability of the silver generation's perception and physical activities, an adaptive game process customized by the individual capability and a user-friendly sensory 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.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.35-45
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• 2006

RIn this paper. we describe real-time parallel processing simulator developed for the use of performance analysis of rolling missiles. The real-time parallel processing simulator developed here consists of seeker emulator generating infrared image signal on aircraft, real-time computer, host computer, system unit, and actual equipments such as auto-pilot processor and seeker processor. Software is developed according to the design requirements of mathematic model, 6 degree-of-freedom module, aerodynamic module which are resided in real-time computer. and graphic user interface program resided in host computer. The real-time computer consists of six TI C-40 processors connected in parallel. The seeker emulator is designed by using analog circuits coupled with mechanical equipments. The system unit provides interface function to match impedance between the components and processes very small electrical signals. Also real launch unit of missiles is interfaced to simulator through system unit. In order to use the real-time parallel processing simulator developed here as a performance analysis equipment for rolling missiles, we perform verification test through experimental results in the field.