• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1249-1253
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• 2001

Numerical analysis is sometimes used to solve the problems in the engineering and natural science fields. On this reason, the faster, more practical system in computing the numerical solution is required. This paper deals with the numerical evaluation of various numerical integration methods which is frequently used in the engineering fields. This paper choices four integration methods such as Euler method, Heun's method, Runge-Kutta method and Gill's method for evaluating the each integration method. In numerical examples, the free vibration problem on an elastic foundation is chosen. As the numerical results, the natural frequencies and the running time are obtained, and these results are compared to examine the practicality of integration methods.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.224-231
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• 2003

The purpose of this study is to review and validate the seismic analysis procedures of turbine-generator foundation specified in the Korea Building Code which adopts equivalent static analysis. Typical machines and foundations were chosen and various kinds of parametric studies were peformed and the results were compared with the detail dynamic analysis. The general trend of the study results showed that the most of the computed responses of equivalent static analysis are smaller than those of the dynamic analyses(response spectrum analysis and time history analysis), which implies the existing seismic analysis technique using the existing Building Code may give unconservative design results. The results also showed that the seismic loads are one of the governing design parameters of the turbine-generator foundations.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.105-108
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• 2006

유비쿼터스 사회는 초고속 인터넷, 모바일, 디지털 컨버전스 단계를 거치면서 점차 가시화되어, 현재 일상적이 커뮤니케니션뿐만 아니라 경제활동 및 산업 분야로 다양하게 확산되고 있다. 특히 RFID와 네비게이션은 국내외적으로 이슈화되고 있으며 점점 발전하고 경제적/산업적으로 국가 경쟁력 향상에 도움을 줄 것으로 보고 있다. 하지만 이러한 FRID와 네비게이션의 쓰임새를 살펴보면 가장 일반적인 경우에 치중되어 있다. 본 논문에서는 FRID와 네비게이션을 사용하여 개별화된 특성을 반영하고 그것을 사용하는 사용자들의 특성을 고려하여 변화하는 환경에 적응하기 쉬운 시스템을 제안하고자 한다. 그리고 특정 환경에서 어떠한 정보가 이에 활용될 수 있는지를 고찰해 보았다. 또한 이러한 정보를 해결하기 위한 퍼지 로직을 적용한다.

• Journal of Environmental Science International
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• v.32 no.7
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• pp.483-492
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• 2023

In this study, the treatment of livestock wastewater using an aerobic granular sludge based sequencing batch reactor was investigated. The reactor operation was carried out by general injection and split injection methods. The average removal efficiency of organic matter after the adaptation period was 71.5 and 87.4%, respectively. Some untreated organic matter was attributed to recalcitrant organic matter. The average removal efficiency of total nitrogen was 65.6 and 88.4%, respectively. These results indicate that the denitrification reaction by split injection was carried out smoothly. As for the solids, the ratio of aerobic granular sludge/mixed liquor suspended solid can be determined as the main factor of the process operation, and the ratio increased gradually and finally reached 86.0%. Correspondingly, the sludge volume index (SVI) was also improved, reaching 54 mL/g at the end of operation, and it is believed that the application of a short settling time contributed to the improvement of settleability.

• Electronics and Telecommunications Trends
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• v.39 no.2
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• pp.24-32
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• 2024

Wearable metaverse devices have sparked enthusiasm as innovative virtual computing user interfaces by addressing a major source of user discomfort, namely, motion-to-photon latency. This kind of latency occurs between the user motion and screen update. To enhance the realism and immersion of experiences using metaverse devices, the vergence-accommodation conflict in stereoscopic image representation must be resolved. Ongoing research aims to address current challenges by adopting vari-focal, multifocal, and light field display technologies for stereoscopic imaging. We explore current trends in research with emphasis on multifocal stereoscopic imaging. Successful metaverse visualization services require the integration of stereoscopic image rendering modules and content encoding/decoding technologies tailored to these services. Additionally, real-time video processing is essential for these modules to correctly and timely process such content and implement metaverse visualization services.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.5
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• pp.171-180
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• 2023

The three major sleep disorders in Korea are snoring, sleep apnea, and insomnia. Lack of sleep is the root of all diseases. Some of the most serious potential problems associated with sleep deprivation are cardiovascular problems, cognitive impairment, obesity, diabetes, colitis, prostate cancer, etc. To solve these problems, the Korean government provided low-cost national health insurance benefits for polysomnography tests in July 2018. However, insomnia patients still have problems getting treated in terms of time, space, and economic perspectives. Therefore, it would be better for insomnia patients to be allowed to test at home. The measuring device can measure six biosignals (eye movement, tossing and turning, body temperature, oxygen saturation, heart rate, and audio). A gyroscope sensor (MPU9250, InvenSense, USA) was used for eye movement, tossing, and turning. The input range of the sensor was in 258°/sec to 460°/sec, and the data range was in the input range. Body temperature, oxygen saturation range, and heart rate were measured by a sensor (MAX30102, Analog Devices, USA). The body temperature was measured in 30 ℃ to 45 ℃, and the oxygen saturation range was 0% for the unused state and 20 % to 90 % for the used state. The heart rate measurement range was in 40 bpm to 180 bpm. The measurement of audio signal was performed by an audio sensor (AMM2742-T-R, PUIaudio, USA). The was -42 dB ±1 dB frequency range was 20 Hz to 20 kHz. The measured data was successfully received in wireless network conditions. The system configuration was consisted of a PC and a mobile app for bio-signal measurement and data collection. The measured data was collected by mobile phones and desktops. The data collected can be used as preliminary data to determine the stage of sleep and perform the screening function for sleep induction and sleep disturbances. In the future, this convenient sleep measurement device could be beneficial for treating insomnia.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.2
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• pp.159-183
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• 2001

The praying sentences of the script of Saddharmapundarika-sutra NO.5 which was made by prayer Bang-Ui, prince Ik-An, was investigated and the cover painting, Byonsangwha(Buddha's preaching painting), and letter style written in the script were discussed in this study. The cover painting on the script is known to be followed to the style of the cover painting as shown in a set of 7 rolls of Saddharma pundarika-sutra of the Horim Museum collection. It is not so difficult to say that the characteristics of cover painting of the script would be suceeded to those of scripts of the end of Koryo and the early Choseon Dynasty. Lotus and its surround was decorated with arabesque figure whose stems were drawn with golden paste and the arabesque figures were done with silver paste. However, for the expression of lotus and arabesque pattern the special feature of drawing style that was originated from the end of Koryo Dynasty to draw the outline with broad line and/or the hardness of drawing line became much more deepened than ever. It is not different to think that this characteristics should be those of Choseon Dynasty. On the Byeonsangwha(buddha's preaching painting) the painting of scattered flowers on stairs of Sumera-Mandala and the scheduled clouds (underseen from heaven) were as similar as to the Byeonsangwha style of the end of Koryo and the early Choseon Dynasty. However, the image of Shakyamuni and/or the halo(光背) is nearly same as the characteristics shown on the Beonsangwha of Saddharma pundarika-sutra of Nesosa' collection, a set of seven rolls which was completed in the 15th year of king Taejong(AD 1415). It is apparent that these characteristics are those of Choseon Dynasty. After king Chungsean in Koryo Dynasty, letter style of Chao Meng-Fu was shown in the script of late Koryo Dynasty as a new letter style.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1082-1086
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• 2018

Purpose: To report a case of a 60-year-old female with rhegmatogenous retinal detachment, presenting with suprachoroidal hemorrhage after vitrectomy. Case summary: A 60-year-old woman visited our clinic complaining of floaters, flashing, and blurred vision. Best-corrected visual acuity was 0.1 in her left eye, and fundus examination of her left eye revealed macula-involved retinal detachment with a retinal break at the superotemporal quadrant. She underwent cataract surgery, 23-gauge transconjunctival sutureless vitrectomy, and 14% C3F8 gas tamponade under general anesthesia. One hour after anesthesia recovery, she suddenly complained of severe pain in her left eye. The intraocular pressure measured after removal of the pressure patch from her left eye was as high as 58 mmHg. Her ocular pain improved spontaneously within 10 minutes, and the intraocular pressure decreased to 8 mmHg. Fundus examination of her left eye revealed a reddish-brown raised lesion, suggesting suprachoroidal hemorrhage. She was placed in a prone position with a pressure patch over her left eye. Bleeding through the sclerotomy site was observed 1 day after surgery. Subsequently, hemorrhagic choroidal detachment of her left eye continued to decrease without deterioration. Three weeks after surgery, the patient received an intravitreal injection of 100% C3F8 gas into her left eye. At 3 months after surgery, best-corrected visual acuity had improved to 0.8 in her left eye, and the retina was stable. Conclusions: Suprachoroidal hemorrhage may be suspected in a patient complaining of severe ocular pain after vitrectomy.

• Journal of the Korean Society for Precision Engineering
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• v.2 no.1
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• pp.21-27
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• 1985

차량, 항공, 교량 및 기계구조물 등 랜덤한 실동하중을 받는 구조물의 응력 및 변위, 진동등의 피로 Data 또는 TRAFFIC 등에 의한 건축물의 변위 및 응력발생빈도를 집록하기 위한 Histogram Recorder System에 대한 내용과 측정예를 소개하고자 한다. 본 System은 8(4)챈 널의 스트레인 게이지 또는 스트레인 게이지식 각종변환기와 각종 Sensor로부터의 출력전압 등 Analog 입력을 수록하여, Digital 처리하여 micro computer를 사용, 미리 프로그램된 방식에 따라 측정과 동시에 실동시간으로 해석처리하여 빈도수로서 내부에 기억저장 시키는 것이다. 따라서 본 Histogtram Recorder 본체는 소형으로 견고하며 조금도 제어부분을 갖지 않고 소요의 해석방법의 프로그램백만을 셋트한 개별의 제어기만을 통해가지고 프로그램을 기입만 하며는 그다음은 손하나 안대고도, 그리고도 또 측정중에 제3자에 의한 제어조작 잘못이 발생할 위험도 없고 1 년이상에 걸친 장기간의 .+-. 32 Slices의 각 레벨당 각각 40 억을 넘는 대량의 빈도수를 자동적으로 집록 할 수가 있다. 집록된 Data는 제어장치에 의해 정리된 Datam는 제어장치에 의해 정리된 Histogram의 형태로 읽어나갈 수가 있어 관찰이 가능할 뿐만 아니라 프린터기록 또는 기록장치에 이송시켜서 Data 만 따로 가져올 수가 있어 필요에 따라서는 one line으로 Host computer에 접속시킬 수가 있어 더욱 고도의 처리를 할 수가 있다. 빈도해석프로그램으로서는 극대, 극소, 최대, 최소, 진폭, 시간 등을 pack으로서 준비되어 있어 이에 대한 시스템의 고성 동작 및 성능등을 소개하고자 한다.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.299-303
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• 1998

To know possibility of raw ginseng production for white- and red-ginseng by direct-sowing culture, seeds were directly sowed or seedlings were transplanted at soil condition of sandy loam in ginseng field. After cultivation, the characters of 5-year-old ginseng were investigated. Number of survived plants was increased with increase the seeding quantity in direct-sowing culture, the survived plants in direct-sowing culture was higher than that of transplanting one. Rate of the numbers of survived plants to numbers of seeds sowed in plots of 134 or 90 seeds sowed per tan, 180 x 90cm area, inspire of high number of survived plant was high compared to that of transplanting culture. Occurrence rate of rusty root of ginseng in direct-sowing culture was low significantly compared to that of transplanting culture. Root yield showed in the order of 134, 268, 90 seeds sowed, the values of yield in direct-sowing culture were high obviously compared to that of transplanting one. Individual root weight was increased with decrease the seeding quantity, however, the root weight in plot of 90 seeds sowed showed almost equal the weight in transplanting culture. The number of usable raw ginseng for white- and red-ginseng was increased with decrease of the seeding quantity; the numbers were higher than that of transplanting culture remarkably. We concluded that optimum seedling rate in direct-sowing culture of ginseng was 90 to 134 seeds per tan considering the yield per area and production rate of large root.