• Korean Journal of Cognitive Science
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• v.26 no.3
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• pp.357-375
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• 2015

In our daily life, the probability of target prevalence in visual search varies from very low to high. However, most laboratory studies of visual search used a fixed probability of target prevalence at 50%. The present study examined the properties of information processing during visual search where the probability of target prevalence was manipulated to vary from low (20%), medium (50%), to high (80%). The search items were made of simple shape stimuli, and search accuracy, signal detection measures, and reaction times (RTs) were analyzed for characterizing the effect of target prevalence on the information processing strategies for visual search. The analyses showed that the rates of misses increased whereas those of false alarms decreased in the search condition of low target prevalence, whereas the pattern was reversed in the high prevalence condition. Signal detection measures revealed that the target prevalence shifted response criterion (c) without affecting sensitivity (d'). In addition, RTs for correct rejection responses in the target-absent trials became delayed as the prevalence increased, whereas those for hits in the target-present trials were relatively constant regardless of the prevalence. The RT delay in the target-absent trials indicates that increased target prevalence made the 'quitting threshold' for search termination more conservative. These results support an account that the target prevalence effect in visual search arises from a shift of decision criteria and the subsequent changes in search information processing, while rejecting the account of a speed-accuracy tradeoff.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.214-221
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• 2019

Visual perception information acquired through human eyes contains much information on how to view visual stimuli using eye tracking technology, it is possible to acquire and analyze consumer visual information as quantitative data. These measurements can be used to measure emotions that customers feel unconsciously, and they can be directly collected by numerically quantifying the character's search response through eye tracking. In this study, we traced the character's area of interest (AOI) and found that the average of fixation duration, count, average of visit duration, count, and finally the time to first fixation was analyzed. As a result of analysis, it was found that there were many cognitive processing processes on the face than the character's body, and the visual attention was high. The visual attention of attraction factor has also been able to verify that attraction is being presented as an important factor in determining preferences for characters. Based on the results of this study, further studies of more characters will be conducted and quantitative interpretation methods can be used as basic data for character development and factors to be considered in determining character design.

• Phonetics and Speech Sciences
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• v.2 no.3
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• pp.151-156
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• 2010

The purpose of this study was to develop a computer-animated pure tone audiometry for screening (CAPTAS) for toddler and to determine its validity and reliability. The CAPTAS utilizes an animated cartoon story producing visual and auditory stimuli. The intensities were 40 dB, 60 dB, 80 dB. The frequencies were 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The subjects were 20 (9 males and 11 females) severely hearing impaired children. As a result, The correlation coefficient between mean hearing threshold of children who were able to perform PTA and average hearing threshold of CAPTAS was performed and it revealed CAPTAS's high validity. And to verify the reliability of the re-test, all children had the CAPTAS and repeated it periodically. The result confirmed the reliability.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.141-141
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• 2001

목적： 최근 들어 컴퓨터 그래픽의 발전과 함께 가상 현실 등에 연구 및 응용이 급증하고 있다. 본 연구의 목적은 fMRI를 이용하여 이차원 및 삼차원 시각자극에 대한 뇌의 기능을 살펴보는 것이다. 같은 영상에 대한 2D와 3D영상을 보여 주면서, fMRI 영상 데이터를 얻었다. 사람에게 미치는 자극 중에 하나인 시각 자극에서 2D와 3D에 대해 반응하는 차이를 규명하고자 하였다. 대상 및 방법： Gradient echo를 기반으로 한 EPI 영상기법을 이용하여, 가톨릭 의대의 3.0 Tesla whole body MRI system에서 실험하였다. 해부학적 영상을 얻기 위해서는 spin echo를 이용하였다. 4명의 volunteer에 대해 같은 영상에 대한 2D와 3D영상을 보여주면서 실험을 수행하였다. 시각자극의 paradigm은 5단계 (rest, active, rest, active, rest)로 하였고, 3번의 rest와 2번의 active구간을 사이에 두었다. 각각의 구간은 10번의 iteration으로 이루어져 있고, 첫 번째 구간은 15번으로 하여 처음 5개의 결과를 버리고, 데이터를 얻었다. 결과는 spm99를 이용하여 분석하였다.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.110-110
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• 2001

목적： 최근 들어 컴퓨터 그래픽의 발전과 함께 가상 현실 등에 연구 및 응용이 급증하고 있다. 본 연구의 목적은 fMRI를 이용하여 이차원 및 삼차원 시각자극에 대한 뇌의 기능을 살펴보는 것이다. 같은 영상에 대한 2D와 3D영상을 보여 주면서, fMRI 영상 데이터를 얻었다. 사람에게 미치는 자극 중에 하나인 시각 자극에서 2D와 3D에 대해 반응하는 차이를 규명하고자 하였다. 대상 및 방법： Gradient echo를 기반으로 한 EPI 영상기법을 이용하여, 가톨릭 의대의 3.0 Tesla whole body MRI system에서 실험하였다. 해부학적 영상을 얻기 위해서는 spin echo를 이용하였다. 4명의 volunteer에 대해 같은 영상에 대한 2D와 3D영상을 보여주면서 실험을 수행하였다. 시각자극의 paradigm은 5단계 (rest, active, rest, active, rest)로 하였고, 3번의 rest와 2번의 active구간을 사이에 두었다. 각각의 구간은 10번의 iteration으로 이루어져 있고, 첫 번째 구간은 15번으로 하여 처음 5개의 결과를 버리고, 데이터를 얻었다. 결과는 spm99를 이용하여 분석하였다.

• Proceedings of the KSPS conference
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• 2003.10a
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• pp.125-127
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• 2003

The aim of the paper is to analyze prosodic characteristics in apraxia of speech and establish the fundamental sources in diagnosis of motor speech disorders. The sentences consist of two different types (declarative and interrogative) with different numbers of constituents which are one to three. The stimuli were constructed to assess apraxics speech with articulation and humming skills. The features of speech patterns were examined such as utterance duration, boundary tones, and etc. The results of the analysis are as follow: 1) In the interrogative sentences, the rising boundary tones appeared only in the humming tasks 2) the utterance duration is relatively shorter in the humming tasks than the speech with articulation.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.383-385
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• 2011

본 논문에서는 동영상을 대상으로 하는 기존의 시각주의 시스템의 성능을 향상시킨 새로운 시스템에 대하여 설명한다. 제안하는 시스템은 기존의 시스템이 가지고 있던 한계점인 서로 반대되는 특징을 가지는 색상에서 하나의 특징만을 고정적으로 선택하던 것을 극복하여, 서로 반대되는 특징 중 현저함이 더 높은 색상 특징을 선택하여 입력 들어오는 영상에 적응적인 현저함 추출을 하였다. 도한 시간 현저함 정보를 추가적으로 고려할 수 있도록 하여 동영상에 대한 처리도 가능하도록 하였고, 성능 평가 시 인간을 대상으로 한 설문 조사 실험을 추가하여 보다 인간의 시각 인식과 유사한 시스템임을 증명하였다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.4
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• pp.252-257
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• 2003

Acrophobia is an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used as a treatment. Lately the virtual reality technology has been applied to that kind of anxiety disorders. A virtual environment provides patient with stimuli which arouses phobia, and exposing to that environment makes him having ability to over come the fear. Recently, the patient can take diagnose from a medical doctor in distance with the telemedicine system. The hospital and doctors can get the medical data, audio, video, signals in the actual examination room or operating room via a live interactive system. Audio visual and multimedia conference service, online questionary, ECG signal transfer system, update system are needed in this system. Virtual reality simulation system that composed with a position sensor, head mount display, and audio system, is also included in this telemedicine system. In this study, we tried this system to the acrophobia patient in distance.

• Animal cells and systems
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• v.4 no.3
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• pp.215-221
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• 2000

Our anatomical and behavioral studies of embryonic rats that developed in microgravity suggest that the vestibular sensory system, like the visual system, has genetically mediated precesses of development that establish crude connections between the periphery and the brain. Environmental stimuli also regulate connection formation including terminal branch formation and fine-tuning of synaptic contacts. Axons of vestibular sensory neurons from grabistatic as well as linear acceleration receptors reach their targets in both microgravity and norm81 gravity, suggesting that this is a genetically regulated component of development. However, microgravity exposure delays the development of terminal branches and synapses in gravistatic but not linear acceleration-sensitive neurons and also produces behavioral changes. These latter changes reflect environmentally controlled processes of development.

• Journal of the Ergonomics Society of Korea
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• v.16 no.2
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• pp.101-122
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• 1997

Our recent work on virtual environments and virtual displays is reviewed, including our efforts to establish the Virtual Environment Research, Interactive Technology, And Simulation (VERITAS) facility and our research on spatial hearing. VERITAS is a state-of -the-art multisensory facility, built around the ${CAVE}^{TM}$ technology. High-quality 3D audio is included and haptic interfaces are planned. The facility will support technical and non-technical users working in a wide variety of application areas. Our own research emphasizes the importance of auditory stimulation in virtual environments and complex display systems. Experiments on auditory-aided visual target acquistion, sensory conflict, sound localization in noise, and loxalization of speech stimuli are discussed.