• Development and Reproduction
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• v.17 no.3
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• pp.231-240
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• 2013

Olive flounder (Paralichthys olivaceus) is one of the commercial important flatfish species in Korea. The ocular signal transduction pathway is important in newly hatched flounders because it is closely involved in the initial feeding phase thus essential for survival during the juvenile period. However, the study of gene expression during ocular development is incomplete in olive flounder. Therefore we examined the expression analysis of specifically induced genes during the development of the visual system in newly hatched flounders. We searched ocular development-involved gene in the database of expressed sequence tags (ESTs) from olive flounder eye and this gene similar to arrestin with a partial sequence homology. Microscopic observation of retinal formation corresponded with the time of expression of the arrestin gene in the developmental stage. These results suggest that arrestin plays a vital role in the visual signal transduction pathway of the retina during ocular development. The expression of arrestin was strong in the ocular system during the entirety of the development stages. Our findings regarding arrestin have important implications with respect to its biological role and evolution of G-protein coupled receptor (GPCR) signaling in olive flounder. Further studies are required on the GPCR-mediated signaling pathway and to decipher the functional role of arrestin.

• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.27-33
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• 2014

The purpose of this study evaluated the hemo-dynamic information within 30 seconds clinically in 3D breast MRI. From January to March 2014, A total of 40 people were examined at 1.5 Tesla(Philips, Medical System, Achieva, The Netherlands) MRI equipments using 16 channel SENSE breast coil. The imaging parameters on vibrant are fellow as: $TR/TE/FA^{\circ}$/Matrix size/Slice thickness/Slab($5ms/2ms/10^{\circ}/180{\times}139{\times}2mm/80$). This study used a Gadovist and injected it with injection speed of 4 ml /sec by auto injector with 15 ml saline flushing. Firstly, for the delay time study, it divided three different delay time from immediately, 20 seconds, and 30 seconds. In quantitative analysis, the ROI signal intensities of tumor and surrounding tissues were measured retrospectively. In qualitative analysis, the image quality was scored from 1 to 5 point by one experienced radiological technologists as a visual test. The significance level of each delay time was evaluated with a one-way ANOVA(p<0.05). In the visual test, score levels on 30 seconds delay time was a little bit higher than others(p<0.05). The signal intensity of the tumor were $1445{\pm}360$, $1410{\pm}320$, $1510{\pm}415$ on immediately, 20 seconds, and 30 seconds and score levels were $4.18{\pm}0.85$, $3.54{\pm}0.94$, $4.45{\pm}0.74$(p<0.05). The data on immediate images showed better results than that others(p<0.05). Conclusively, Although it has been high scored in 30sec delay time for visual test in order to avoid failure in 20second, 30seconds delay time after contrast media administration, we recommend that the DCE 3D breast MRI commence immediately.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.2
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• pp.77-82
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• 2016

The purpose of this paper is to develop the algorithm of human arousal inducing interface using steady-state visual evoked potential(SSVEP) and its verification through experiments. In order to develop the model, computer-based SSVEP program simulation is preliminary performed. From the results of the simulation, stimulus pattern is decided to checkerboard and SSVEP frequency range is set into beta wave (13~30Hz). After the experiment on proving the effect of SSVEP flashing stimulation while driving by installing it at the location of people mostly falling asleep in the highway, the result confirms that both during the night and the day, after SSVEP flashing stimulation, a wave Beta immediately increases and the subjects keep high stimulation for the 5 minute maintaining stage.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.1
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• pp.13-19
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• 2011

In this paper, a visual surveillance system using SOPC based NIOS II embedded processor and C2H compiler was implemented. In this system, the IP is constructed by C2H compiler for the output of the camera images, image processing, serial communication and network communication, then, it is implemented to effectively control each IP based on the SOPC and the NIOS II embedded processor. And, an algorithm which updates the background images for high speed and robust detection of the moving objects is proposed using the Adaptive Gaussian Mixture Model(AGMM). In results, it can detecte the moving objects(pedestrians and vehicles) under day-time and night-time. It is confirmed that the proposed AGMM algorithm has better performance than the Adaptive Threshold Method(ATM) and the Gaussian Mixture Model(GMM) from our experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.583-584
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• 2022

Due to the development of drones, drone missions are performed in various fields, and BVLOS (Beyond Visual Line Of Sight) flight is performed in a wide area. Most drones operate through radio frequency (RF) communication and can only fly in a limited radius of about 1-2 km. To overcome this, in this paper, we propose a multi-communication protocol-based drone control system to control drones performing missions in BVLOS using RF and LTE (Long Term Evolution). The proposed system consists of a control unit and a drone unit. The control unit transmits one control signal generated from the remote controller through RF and LTE. The drone unit classifies the control signal transmitted through RF and LTE according to the priority of the communication protocol and delivers it to the FC (Flight Controller). Through the proposed control system, it is possible to overcome the RF communication distance limit and prevent the communication disconnection situation.

• Journal of Biomedical Engineering Research
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• v.45 no.2
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• pp.101-107
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• 2024

Steady-state visual evoked potential-based brain-computer interface (SSVEP-BCI) is one of the promising systems that can serve as an alternative input device due to its stable and fast performance. However, one of the major bottlenecks is that some individuals exhibit no or very low SSVEP responses to flickering stimulation, known as SSVEP illiteracy, resulting in low performance on SSVEP-BCIs. However, a lengthy duration is required to enhance multiple SSVEP responses using traditional single-frequency transcranial alternating current stimulation (tACS). This research proposes a novel approach using dual-frequency tACS (df-tACS) to potentially enhance SSVEP by targeting the two frequencies with the lowest signal-to-noise ratio (SNR) for each participant. Seven participants (five males, average age: 24.42) were exposed to flickering checkerboard stimuli at six frequencies to determine the weakest SNR frequencies. These frequencies were then simultaneously stimulated using df-tACS for 20 minutes, and the experiment was repeated to evaluate changes in SSVEP responses. The results showed that df-tACS effectively enhances the SNR at each targeted frequency, suggesting it can selectively improve target frequency responses. The study supports df-tACS as a more efficient solution for SSVEP illiteracy, proposing further exploration into multi-frequency tACS that could stimulate more than two frequencies, thereby expanding the potential of SSVEP-BCIs.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.4
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• pp.199-204
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• 2023

Production technologies in the imaging sector are innovating continuously and due to the visual experiences of powerful screen effects using 3D technologies, the public is now pursuing higher quality and more realistic visual effects. 3D production software with greater performance to realize this are now flooding the market, but artificial manual work and traditional hand-painting HDRI production methods still exist. There are few studies on new methods using HDRI production software using the computer's high performance data operations. In order to improve HDRI pipelines, this study links the two technological points of 'Nuke' and 'Photoshop' and it reduced production time and the improvements of quality were verified by using pipelines with new convergence methods.

• Korean Journal of Cognitive Science
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• v.34 no.1
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• pp.1-20
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• 2023

In this study, we examined the effects of spatial attention in Hangul word recognition depending on visual factors. The visual complexity of words (Experiment 1) and contrast (Experiment 2) were manipulated to examine whether the effect of spatial attention differs depending on visual quality. Participants responded to words with and without codas in experiment 1 and words in high-contrast and low-contrast conditions in experiment 2. The effects of spatial attention were investigated by calculating the difference in performance between the condition where spatial cues were given at the target location (valid trial) and the condition where the spatial cues were not given at the target location (invalid trial) as the cuing effects. As a result, the cuing effects were similar depending on the complexity of the words. It indicates that the effects of spatial attention were not different across the visual complexity conditions. The cuing effects were greater in the low-contrast condition than in the high-contrast condition. The greater effect of spatial attention when the contrast is low was explained as a mechanism of signal enhancement.

• Journal of Broadcast Engineering
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• v.13 no.6
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• pp.951-961
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• 2008

Cooperative diversity is a cooperative technique which exploits user diversity by decoding the combined signal of the relayed signal and the direct signal in wireless multi-hop networks. Using the cooperation, the performance of the network system can be improved because cooperative diversity which is very strong against the fading channels can be achieved. In this paper, we propose the technique that provides the enhanced visual quality of the reconstructed video using the cooperative diversity with the FMO which is the error resilience tool of H.264/AVC standardization over wireless networks. The eye-tracker can detect the gaze point of user and transmit the gaze information to the nodes. After receiving the gaze information of user, each node performs ROI encoding according to the received gaze information. After encoding, video sources are divided into ROI and Non-ROI. Through the simulation results, the better visual quality of the reconstructed video is achieved when ROI and Non-ROI are transmitted through different channels.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.1
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• pp.8-11
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• 2012

Automated Vision Inspection (AVI) systems automatically detect any defect feature in a surface image. The performance of the system can be measured under a special circumstances such as ultimate defect detection. In this situation, the defect signal level is similar to noise level and it becomes hard to make a solid decision with AVI systems. In this paper, we propose an effective preprocessing technique to enhance SNR (Signal to Noise Ratio). The method is motivated by some principles of HVS (Human Visual System) and RLC (Run Length Coding) techniques is used for this purpose. The proposed preprocessing technique enhances SNR under ultimate defect conditions and improves overall performance of AVI system.