• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.05a
• /
• pp.64-66
• /
• 2023

Low Earth Orbit(LEO) Non-Terrestrial-Network(NTN) 은 위성을 사용하여 통신 서비스를 제공하지 못하는 도시 이외의 산간, 바다, 항공기 또는 외진 지역에 통신 서비스를 제공하는 모델이다. Terrestrial Network(TN) 핸드오버에서 사용되는 Measurement-Based Triggering(MHT)의 경우 User Equipment(UE)에서 측정된 값을 기반으로 Measurement Report를 전달한다. 그러나 NTN 환경에서의 HO triggering은 TN 과는 달리 장거리 통신을 요구하고 위성이 빠른 속도로 이동함에 따라 MHT에 사용되는 지표들을 대체할 방법이 필요하다. 이 논문에서는 측정 유효성을 대체할 수 있는 지표로 UE와 셀 중심 간의 거리 및 고도 각을 활용하여 HO triggering을 예측하는 시스템을 제안한다. 제안한 예측 시스템은 핸드오버 triggering 예측에 대해 우수한 성능을 보였으며 좋은 측정 결과를 얻을 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.10
• /
• pp.2338-2356
• /
• 2013

In cognitive radio networks, acquiring the position information of the primary user is critical to the communication of the secondary user. Localization of primary users can help improve the efficiency with which the spectrum is reused, because the information can be used to avoid harmful interference to the network while simultaneity is exploited to improve the spectrum utilization. Despite its inherent inaccuracy, received signal strength based on range has been used as the standard tool for distance measurements in the location detection process. Most previous works have employed the path-loss propagation model with a fixed value of the path loss exponent. However, in actual environments, the path loss exponent for each channel is different. Moreover, due to the complexity of the radio channel, when the number of channel increases, a larger number of RSS measurements are needed, and this results in additional energy consumption. In this paper, to overcome this problem, we propose using the Bayesian compressive sensing method with a calibrated path loss exponent to improve the performance of the PU localization method.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.5
• /
• pp.143-150
• /
• 2017

In this paper, we propose a novel motion recognition platform using smart-phone tracking and color communication. The interface requires only a camera and a personal smart-phone to provide a motion control interface rather than expensive equipment. The platform recognizes the user's gestures by the tracking 3D distance and the rotation angle of the smart-phone, which acts essentially as a motion controller in the user's hand. Also, a color coded communication method using RGB color combinations is included within the interface. Users can conveniently send or receive any text data through this function, and the data can be transferred continuously even while the user is performing gestures. We present the result that implementation of viable contents based on the proposed motion recognition platform.

• Proceedings of the IEEK Conference
• /
• 2003.07d
• /
• pp.1657-1660
• /
• 2003

7 This paper offer to the system for the hierarchical face plastic surgery using of 3D models. For the system, Make hierarchical plastic object of facial 3D models, and special appointment setting of plastic object. In order to give variaty to a scale, type, angle, position of plastic object that developed plastic surgery solution. It is possible to plastic surgery that harmonize with plastic objects, solution, vector by selected user.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.409-414
• /
• 2003

This paper develops a relatively comprehensive and sophisticated constitutive model of concrete for finite element analysis of concrete structures. The present model accounts for the hydrostatic pressure sensitivity and Lode angle dependence behavior of concrete, not only in its strength criterion, but also in its hardening characteristics. The implementation is carried out through incorporating the developed concrete model in User Subroutine Material(UMAT) of the general-purpose FE program ABAQUS(v.5.8). It is found that the model can sufficiently predict the hardening as well as the softening behaviour of concrete under high confining pressure.

• Proceedings of the ESK Conference
• /
• 1997.10a
• /
• pp.320-325
• /
• 1997

It is very diffcult to applied ergonomics data & experiments in industrial design. At the industrial design process attempted toadoption a egonomics. But sometimes easyto use ergonomics data and at other times very hard to adopted a element into a design process. Industrial design of the essence is a sensual act. As ergonomics data is to the hardware, sois the design sense to the software. The harmony are important to hardware & software of design process. New products demand to new form. Therefore, designer neglect to ergonomics experiments for user. Anyway, ergonomics experiments & data endlessly applied to more things year after year. This paper show improved computer front design with graphic, knobs size & control panel tilt angle.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.6
• /
• pp.623-629
• /
• 2014

The purpose of this study is to analyze user requirements of photovoltaic generating facilities for detached houses. For the analysis, 202 households that installed photovoltaic generating facilities to conduct a survey. According to the survey results, users mainly demanded 'Reduction in self-burden amount' and 'Maintenance Services.' In addition, when conducting 'Education for photovoltaic generating facilities', they highly wanted to participated in it. Results on the installation status of photovoltaic generating facilities are as follows: Of locations where photovoltaic generating facilities are installed, the most households installed them on the roof, 54%. As for the angle in which photovoltaic module is installed, the range of $25{\sim}35^{\circ}$ was the most common and in the case of installation direction, southern exposure accounted for the rate of 93%. The monthly average generation of households surveyed is approximately 320kWh. Research on technology and policy to address user requirements shown in this study is deemed necessary in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.55-63
• /
• 2013

In cognitive radio networks, acquirement of position information of primary user is very important to secondary network since localization information of primary users can be utilized for improving the spectrum efficiency of secondary network and for avoiding harmful interference to primary users by using proper power control. Among various location methods, Received Signal Strength (RSS)-based localization has been widely used for distance measurements in the location detection process despite its inherent inaccuracy because it can be easily implemented without any additional hardware cost. In the RSS-based localization, the distance is measured by the received signal strength, and distance error can be caused by many factors such as fading, shadowing and obstacle between two nodes. In the paper, therefore we propose a localization scheme based on estimation of path-loss exponent to localize the location of primary users more accurately. Through simulations, it is shown that the proposed scheme can provide less localization error and interference rate to primary users than other schemes.

• Science of Emotion and Sensibility
• /
• v.17 no.2
• /
• pp.91-100
• /
• 2014

This study was to examine how visual angle of matrix corresponding to the physical properties of P300 speller and eye gaze corresponding to the user's personal characteristics influence on the accuracy of P300. Visual angle of the matrix was operated as the distance between the user and the matrix and three groups were composed: 60 cm group, 100 cm groups, and 150 cm group. Eye gaze methods was consisted three conditions. Head moving condition was putting eye gaze using head, pupil moving condition was moving pupil with the head fixed, while the eye fixed condition is to fix the eye gaze at the center of the matrix. The results showed that there was significant difference in the accuracy of P300 speller according to the eye gaze method. The accuracy of the head moving condition was higher than the accuracy of pupil moving conditions, accuracy of pupil moving conditions was higher than the accuracy of the eye fixed conditions. However, the effect of visual angle of matrix and interaction effect were not significant. When P300 amplitude of target character was measured depending on how you stare at the target character, P300 amplitude of the head moving condition was greater than P300 amplitude of the pupil moving condition. There was no significant difference in the error distribution in head moving condition and pupil moving condition, while there was a significant difference between two eye gaze conditions and fixed gaze condition. The error was located at the neighboring characters of the target character in head moving condition and pupil moving condition, while the error was relatively distributed widely in fixed eye condition, error was occurred with high rate in characters far away from the center of matrix.

• Korean Journal of Optics and Photonics
• /
• v.33 no.2
• /
• pp.67-73
• /
• 2022

In a head-mounted display (HMD) for virtual-reality applications, a narrow viewing angle is preferred to the usual, wide viewing angle because the HMD is positioned close in front of the user's eyes, and the display position is fixed. In this paper, we propose a new back-light unit (BLU) for implementing a narrow viewing angle, which is suitable for a HMD. By optimizing the scattering patterns in the light-guide-plate and inverse-prism structures, the viewing angle and correlations between structural parameters in the BLU components are analyzed with ray-tracing simulations. As a result, a double-angle inverse-prism structure incorporating the scattering patterns of a light-guide plate is chosen, which results in a 14% increase in center luminance, a 16% decrease in the vertical viewing angle, and a light efficiency of up to 70%, compared to a conventional BLU. Thus, the new BLU system is expected to be applied in a high-efficiency liquid crystal display.