• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.111-121
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• 2011

Intelligent video analysis systems require techniques which can predict accidents and provide alarms to the monitoring personnel. In this paper, we present an abnormal behavior analysis technique based on adaptive background generation. More specifically, abnormal behaviors include fence climbing, abandoned objects, fainting persons, and loitering persons. The proposed video analysis system consists of (i) background generation and (ii) abnormal behavior analysis modules. For robust background generation, the proposed system updates static regions by detecting motion changes at each frame. In addition, noise and shadow removal steps are also were added to improve the accuracy of the object detection. The abnormal behavior analysis module extracts object information, such as centroid, silhouette, size, and trajectory. As the result of the behavior analysis function objects' behavior is configured and analyzed based on the a priori specified scenarios, such as fence climbing, abandoning objects, fainting, and loitering. In the experimental results, the proposed system was able to detect the moving object and analyze the abnormal behavior in complex environments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.98-105
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• 2013

This paper presents a finite-difference time-domain(FDTD) simulation and a data processing technique for radar sensing of the internal structure of a wall using an ultra-wide band antenna. We first designed an ultra-wide band anti-podal vivaldi antenna with a frequency range of 0.3~7 GHz which is chosen to be relatively low after considering the characteristics of wave attenuation, wall penetration, and range resolution. In this study the two-dimensional FDTD technique was used to simulate a wall-penetration-radar experiment under practical conditions. The next, the measured radiation pattern of the practical antenna is considered as an equivalent source in the FDTD simulation, and the reflection data of a concrete wall and targets are obtained by using the simulation. Then, a data processing technique has been applied to the FDTD reflection data to get a radar image for remote sensing of the internal structure of the wall. We compared the two different source excitations in the FDTD simulation; (1) commonly-used isotropic point sources and (2) polynomial curve fitting sources of the measured radiation pattern. As a result, when we apply the measured antenna pattern into the FDTD simulation, we could obtain about 2.5 dB higher signal to noise level than using a plane wave incidence with isotropic sources.

• Journal of Oral Medicine and Pain
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• v.23 no.3
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• pp.289-294
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• 1998

본 증례는 측두하악관절의 퇘행성 변화를 보이는 환자에서 악교정 수술의 시행 전에 중심위교합장치를 통해 측두하악관절의 안정화를 유도하고, 또한 골스캔을 이용하여 장치의 치료효과를 평가한 임상증례이다. 환자는 24세의 여성으로 5년 전부터 전치부 개교합이 발생되기 시작하였고, 고형식 저작시 좌측 전이부에 간헐적인 통증이 발생한다는 주소로 본원에 내원하였다. 임상검사상 촉진시 양측 관절낭 후방부에 압통을 호소하였으며, 각각 50, 45mm의 최대개구량 및 최대무통성 개구량을 보였다. 좌측 악관절부에서 단순 관절 잡음, 우측 악관절부에서 염발음이 청취되었으며, 저항검사 및 부하 검사에서는 특기할 반응을 보이지 않았다. 약 7mm의 전치부 개교합의 소견을 보였으며, 파노라마 사진과 횡두개 방사선 사진 소견상 양측 과두의 크기 및 하악지의 높이가 다소 작은 소견이 관찰되었고 자기공명영상 소견상 양측성 비정복성 관절원판의 전방전위가 관찰되었다. 1997년 10월 27일 첫 번째 골스캔 소견상 양측성 비정복성 관절원판의 전방위가 관찰되엇다. 골스캔의 전방 사진에서 Densitometer를 이용하여 좌, 우측 과두부위와 상악 골부위의 가장 어두운 부분의 흑화도를 측정하였다. 각각 3회씩 구하여 평균을 구하고 좌, 우측 과두 대 상악골의 흑화도의 비율을 계산하였다. 첫번째 골스캔의 평균 흑화도는 우측 과두, 좌측과두, 상악골이 각각 0.88, 0.81, 1.32 였다. 1997년 11월 4일 중심위교합장치를 장착하였고 지속적인 물리치료를 시행하였다. 1997년 12월 10일 두 번째 골 스캔을 평균 흑화도는 우측 과두, 좌측 과두, 상악골이 각각 0.33, 0.37, 088 이었다. 1998년 1월 30일 세 번째 골스캔 소견상 두 번째 골스캔과 비교하여 활성도가 감소된 소견을 보였다. 임상검사시 무통이었다. 1998년 2월 25일 술 전 교정 위해 중심위교합장치의 장작을 중지시켰다. 1998년 6월 5일 네 번째 골스캔 소견상 이전 검사들과 비교시 흡수가 감소된 소견을 보였다. 네 번째 골스캔의 평균 흑화도는 우측 과두, 좌측 과두, 상악골이 각각 0.24, 0.19, 0.85 였다. 현재 지속적인 관찰 중이며 본원 교정과에서 악교정수술 위한 술 전 교장을 시행중이다. 결국 첫 번째 골스캔의 과두 대 상악골의 평균 흑화도의 비율은 우측과 좌측이 각각 0.66, 0.61이었고 두 번째 골스캔에서는 우측과 좌측이 각각 0.37, 0.42였고, 네번째 골스캔에서는 우측과 좌측이 각각 0.28, 0.23 이었다. 각 골스캔의 과두 대 상악골의 평균 흑화도의 비율 사이에 유의한 차이가 있는지 검증하기 위해 Standard t-test 와 ANOVA를 시행하였다. 이상의 결과에서 첫 번째, 두 번째, 네 번째 골스캔으로 갈수록 좌, 우측 과두 대 상악골의 흑화도의 비율이 유의하게 감소했음을 알 수 있었다. 결론적으로 본 증례에서는 전치부 개교합이 발생되어 악교정수술이 필요한 환자에게 측두하악관절의 안정화를 위해 중심위교합장치를 사용함으로써 퇴행성 관절질환의 진행을 억제시킬 수 있고, 퇴행성 관절질환의 활성도에 대한 평가시 골스캔이 유용할 수 있음을 보여주었다고 사료된다.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.299-308
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• 2002

We have derived an analytical expression for the sensitivity of the frequency domain small-loop electromagnetic (EM) surveys over a two-layer earth in order to estimate the depth of investigation with an instrument having the source-receiver separation of about 2 m. We analyzed the sensitivities to the lower layer normalized by those to the upper half-space and estimated the depth of investigation from the sensitivity analyses and the mutual impedance ratio. The computational results showed that the in-phase components of the sensitivity to the lower layer dominates those to the upper layer when the thickness of the upper layer is less than 20 m, while the quadrature components are not sensitive to the lower layer over the entire frequency range. Hence we confirmed that the accurate measurement of the in-phase component is essential to increase the depth of investigation in the multi-frequency small-loop EM survey. When conductive basement of 10 ohm-m underlies the upper layer of 100 ohm-m, an accurate measurement of the in-phase components ensures the depth of the investigation more than 10 m even accounting a noise effect, from which we conclude that the small-loop EM survey is quite effective in imaging the conductive plume down to a considerable depth. On the other hand, in the presence of the resistive basement of 1,000 ohm-m, the depth of investigation may not exceed 5 m considering the instrumental accuracy, which implies that the application of the small-loop EM survey is not recommended over the resistive environment other than detecting the buried conductor.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.69-79
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• 2008

Due to popularization of the wireless Internet and mobile devices the infrastructure of the ubiquitous environment, where users can get information whatever they want anytime and anywhere, is created. Therefore, a variety of fields including the education studies methods for efficiency of information transmission using on-line and off-line contents. In this paper, we propose the Mixed Mobile Education system(MME) that improves educational efficiency using on-line and off-line contents on mobile devices. Because it is hard to input new data and cannot use similar off-line contents in systems used additional tags, the proposed system does not use additional tags but recognizes of-line contents as we extract feature points in the input image using the mobile camera. We use the Scale Invariant Feature Transform(SIFT) algorithm to extract feature points which are not affected by noise, color distortion, size and rotation in the input image captured by the low resolution camera. And we use the client-server architecture for solving the limited storage size of the mobile devices and for easily registration and modification of data. Experimental results show that compared with previous work, the proposed system has some advantages and disadvantages and that the proposed system has good efficiency on various environments.

• Geophysics and Geophysical Exploration
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• v.6 no.4
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• pp.171-179
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• 2003

In land and marine seismic survey, we generally set receivers with equal interval suppose that sampling interval Is too narrow. But the cost of seismic data acquisition and that of data processing are much higher, therefore we should design proper receiver interval. Spatial aliasing can be occurred on seismic data when sampling interval is too coarse. If we Process spatial aliasing data, we can not obtain a good imaging result. Trace interpolation is used to improve the quality of multichannel seismic data processing. In this study, we applied the Spitz algorithm which is widely used in seismic data processing. This algorithm works well regardless of dip information of the complex underground structure. Using prediction filter and original traces with linear event we interpolated in f-x domain. We confirm our algorithm by examining for some synthetic data and marine data. After interpolation, we could find that receiver intervals get more narrow and the number of receiver is increased. We also could see that continuity of traces is more linear than before Applying this interpolation algorithm on seismic data with spatial aliasing, we may obtain a better migration imaging.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.21-29
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• 2019

The purpose of this study was to compare the MI using SonoVue along with different machines output and to infer the meaning of the signal difference under the same condition. All of the comparative instruments showed strong signal values at early stage as MI value increased. Over time, the inter-instrumental signal values showed signal attenuation under all conditions except for 10 min of the condition of MI 0.1 of RS85A. E9 and EPIQ7 showed signal degradation due to microbubble collapse over time at all MI values. In the comparison of equipment, the signal strengths of MI 0.1, 0.2, and 0.4 were high in order of EPIQ7, RS85A and E9. In the quantitative analysis, there were statistically significant from the SNR and CNR that were obtained from RS85A and E9 (P-value<0.05). In the quantitative analysis, Epiq7 was statistically significant except for CNR as the MI value was changed In the contrast-enhanced ultrasound, even though MI value was low (MI <0.05), it will be helpful for diagnosis, controlling the MI and scan time because a difference in signal intensity was shown between the three machines.

• Geophysics and Geophysical Exploration
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• v.25 no.3
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• pp.129-139
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• 2022

Analog-based streamers for ultra-high-resolution seismic surveys are capable of additional noise ingress in water, but the specifications cannot be expanded through interconnections. Foreign-produced digital streamers have been introduced and used primarily at domestic research institutes; however, the cost is high and smooth maintenance is challenging. This study investigates the localization of ultra-high-resolution digital streamers capable of high-resolution imaging of a geological structure. A digital streamer capable of 24-bit, 10 kHz digital sampling of up to 64 channel data was developed through research and development. Various quantitative specifications of the system were designed and developed close to the benchmark model, Geometrics' GeoEel streamer, and the number of modules that make up the system was drastically reduced, reducing development costs and making it easier to use. The field applicability of the developed streamer system was evaluated in an in situ experiment conducted in the waters around the Port of Yeong-il Bay in Pohang in April 2022.

• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.37-51
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• 2023

The ground roll is the most common coherent noise in land seismic data and has an amplitude much larger than the reflection event we usually want to obtain. Therefore, ground roll suppression is a crucial step in seismic data processing. Several techniques, such as f-k filtering and curvelet transform, have been developed to suppress the ground roll. However, the existing methods still require improvements in suppression performance and efficiency. Various studies on the suppression of ground roll in seismic data have recently been conducted using deep learning methods developed for image processing. In this paper, we introduce three models (DnCNN (De-noiseCNN), pix2pix, and CycleGAN), based on convolutional neural network (CNN) or conditional generative adversarial network (cGAN), for ground roll suppression and explain them in detail through numerical examples. Common shot gathers from the same field were divided into training and test datasets to compare the algorithms. We trained the models using the training data and evaluated their performances using the test data. When training these models with field data, ground roll removed data are required; therefore, the ground roll is suppressed by f-k filtering and used as the ground-truth data. To evaluate the performance of the deep learning models and compare the training results, we utilized quantitative indicators such as the correlation coefficient and structural similarity index measure (SSIM) based on the similarity to the ground-truth data. The DnCNN model exhibited the best performance, and we confirmed that other models could also be applied to suppress the ground roll.

• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.62-76
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• 2023

Recently, machine learning (ML) techniques have been actively applied for seismic trace interpolation. However, because most research is based on training-inference strategies that treat missing trace gather data as a 2D image with a blank area, a sufficient number of fully sampled data are required for training. This study proposes trace interpolation using ML, which uses only irregularly sampled field data, both in training and inference, by modifying the training-inference strategies of trace-based interpolation techniques. In this study, we describe a method for constructing networks that vary depending on the maximum number of consecutive gaps in seismic field data and the training method. To verify the applicability of the proposed method to field data, we applied our method to time-migrated seismic data acquired from the Vincent oilfield in the Exmouth Sub-basin area of Western Australia and compared the results with those of the conventional trace interpolation method. Both methods showed high interpolation performance, as confirmed by quantitative indicators, and the interpolation performance was uniformly good at all frequencies.