Filters








445 Hits in 1.6 sec

EEG-based neurocinematics: challenges and prospects

Ho-Seung Cha, Won-Du Chang, Young Seok Shin, Dong Pyo Jang, Chang-Hwan Im
2015 Brain-Computer Interfaces  
Neurocinematics is an emerging research discipline that studies audiences' cognitive and affective responses to cinematic stimuli. To date, functional magnetic resonance imaging (fMRI) has been the most widely used research tool for neurocinematics studies; however, recent studies have shown that electroencephalography (EEG) can also be a promising tool for neurocinematics studies thanks to its excellent temporal resolution. In this article, after discussing challenges and prospects for
more » ... d neurocinematics, we introduced two potential film-rating indices named 'empathy index' and 'reactivity index' as examples of EEG-based neurocinematic markers. Preliminary experiments showed that the new indices have the potential to be used as promising tools for film evaluation.
doi:10.1080/2326263x.2015.1099091 fatcat:dnswuhqwengdbjsumno2fuxeum

Cortical volume and 40-Hz auditory-steady-state responses in patients with schizophrenia and healthy controls

Sungkean Kim, Seon-Kyeong Jang, Do-Won Kim, Miseon Shim, Yong-Wook Kim, Chang-Hwan Im, Seung-Hwan Lee
2019 NeuroImage: Clinical  
Abnormalities in the 40-Hz auditory steady-state response (ASSR) of the gamma range have been reported in schizophrenia (SZ) and are regarded as important pathophysiological features. Many of the previous studies reported diminished gamma oscillations in SZ, although some studies reported increased spontaneous gamma oscillations. Furthermore, brain morphological correlates of the gamma band ASSR deficits have rarely examined. We investigated different measures of the 40-Hz ASSR and their
more » ... tion with brain volumes and psychological measures of SZ.
doi:10.1016/j.nicl.2019.101732 pmid:30851675 pmcid:PMC6407311 fatcat:nyhlhxt5jbem5kwxh4jd4nvmoa

Updates on the Sedation for Gastrointestinal Endoscopy

Jun Kyu Lee, Yoo Jin Lee, Jun Hyung Cho, Jong Pil Im, Chang-Hwan Park, Jae-Young Jang, Byung Ik Jang, the Quality Management Committee and the Disinfection Management/Conscious Sedation Committee of Korean Society of Gastrointestinal Endoscopy (KSGE)
2019 Clinical Endoscopy  
Sedation, defined as the depressed level of consciousness, induced by drug administration, is widely used for gastrointestinal endoscopy to relieve a patient's anxiety and discomfort. In addition, successful procedure is anticipated with control of unintended movements. Endoscopic sedation, however, cannot be free from the risk of serious adverse events, e.g., cardiopulmonary compromise. Therefore, principles on personnel, facility and equipment, as well as performance itself, should be
more » ... to prevent unfavorable incidents. In this article, sedation guidelines for the Accreditation of Qualified Endoscopy Units, issued by the Korean Society of Gastrointestinal Endoscopy, are presented.
doi:10.5946/ce.2019.172 pmid:31591282 pmcid:PMC6785422 fatcat:5cla7vlzonf2tolru6drhq4pwq

Electrophysiological correlates of cognitive inhibition in college students with schizotypal traits

Myung-Sun Kim, Sung Hwa Oh, Kyoung Mi Jang, Huije Che, Chang-Hwan Im
2012 Open Journal of Psychiatry  
Objective: We investigated cognitive inhibition in nonclinical individuals with schizotypal traits using eventrelated potentials. Methods: College students with psychometrically defined schizotypal traits (n = 16) and normal controls (n = 15) participated. The computerized Stroop task with three types of stimuli, i.e., congruent, incongruent, and neutral words, was used to measure cognitive inhibition. Results: The schizotypaltrait group committed significantly more errors in response to
more » ... uent words than did the control group. The control group showed frontal negativity (FN) of significantly greater amplitude in response to incongruent than to congruent and neutral stimuli, whereas the schizotypal-trait group showed no significant difference in FN amplitude between incongruent and congruent/neutral stimuli at 300 -400 ms poststimulus. A source localization analysis conducted in different waveforms for incongruent minus congruent conditions at 300 -400 ms poststimulus showed reduced activation in the left cingulate cortex and in the middle/medial prefrontal cortex in the schizotypal-trait group compared with the control group. The two groups did not differ in the sustained potential amplitudes observed at 550 -650 ms after stimulus-onset at parietal sites. Conclusions: These results suggest that individuals with schizotypal traits have difficulties in conflict detection and cognitive inhibition, possibly mediated by the cingulate cortex and prefrontal cortex.
doi:10.4236/ojpsych.2012.21010 fatcat:6ewq44vwmbfizjkui5ask6zpwa

Compensation of Current Offset Error in Half-Bridge PWM Inverter for Linear Compressor

Dong-Youn Kim, Won-Sang Im, Seon-Hwan Hwang, Jang-Mok Kim
2015 Journal of Power Electronics (JPE)  
 A Parameter of Linear Compressor Rate Power 750 W Rate Frequency 60 Hz Inductance 350 mH Register 10 Ω Journal of Power Electronics, Vol. 15, No. 6, November 2015 Jang-Mok  ... 
doi:10.6113/jpe.2015.15.6.1593 fatcat:telozeqbonb4ldvjdol4u5qupe

Correlation between Inter-Blink Interval and Episodic Encoding during Movie Watching

Young Seok Shin, Won-du Chang, Jinsick Park, Chang-Hwan Im, Sang In Lee, In Young Kim, Dong Pyo Jang, Benjamin Thompson
2015 PLoS ONE  
Human eye blinking is cognitively suppressed to minimize loss of visual information for important real-world events. Despite the relationship between eye blinking and cognitive state, the effect of eye blinks on cognition in real-world environments has received limited research attention. In this study, we focused on the temporal pattern of inter-eye blink interval (IEBI) during movie watching and investigated its relationship with episodic memory. As a control condition, 24 healthy subjects
more » ... ched a nature documentary that lacked a specific story line while electroencephalography was performed. Immediately after viewing the movie, the subjects were asked to report its most memorable scene. Four weeks later, subjects were asked to score 32 randomly selected scenes from the movie, based on how much they were able to remember and describe. The results showed that the average IEBI was significantly longer during the movie than in the control condition. In addition, the significant increase in IEBI when watching a movie coincided with the most memorable scenes of the movie. The results suggested that the interesting episodic narrative of the movie attracted the subjects' visual attention relative to the documentary clip that did not have a story line. In the episodic memory test executed four weeks later, memory performance was significantly positively correlated with IEBI (p<0.001). In summary, IEBI may be a reliable bio-marker of the degree of concentration on naturalistic content that requires visual attention, such as a movie.
doi:10.1371/journal.pone.0141242 pmid:26529091 pmcid:PMC4631519 fatcat:fli4s73ptzevregrj7mtq6w6ta

Transient Global Amnesia Deteriorates the Network Efficiency of the Theta Band

Young Ho Park, Jeong-Youn Kim, SangHak Yi, Jae-Sung Lim, Jae-Won Jang, Chang-Hwan Im, SangYun Kim, Francisco J. Esteban
2016 PLoS ONE  
Acute perturbation of the hippocampus, one of the connector hubs in the brain, is a key step in the pathophysiological cascade of transient global amnesia (TGA). We tested the hypothesis that network efficiency, meaning the efficiency of information exchange over a network, is impaired during the acute stage of TGA. Graph theoretical analysis was applied to resting-state EEG data collected from 21 patients with TGA. The EEG data were obtained twice, once during the acute stage (< 24 hours after
more » ... symptom onset) and once during the resolved stage (> 2 months after symptom onset) of TGA. Characteristic path lengths and clustering coefficients of functional networks constructed using phase-locking values were computed and normalized as a function of the degree in the delta, theta, alpha, beta 1, beta 2 and gamma frequency bands of the EEG. We investigated whether the normalized characteristic path length (nCPL) and normalized clustering coefficients (nCC) differed significantly between the acute and resolved stages of TGA at each frequency band using the Wilcoxon signed-rank test. For networks where the nCPL or nCC differed significantly between the two stages, we also evaluated changes in the connections of the brain networks. During the acute stage of TGA, the nCPL of the theta band networks with mean degrees of 8, 8.5, 9 and 9.5 significantly increased (P < 0.05). During the acute stage, the lost edges for these networks were mostly found between the anterior (frontal and anterior temporal) and posterior (parieto-occipital and posterior temporal) brain regions, whereas newly developed edges were primarily found between the left and right frontotemporal regions. The nCC of the theta band with a mean degree of 5.5 significantly decreased during the acute stage (P < 0.05). Our results indicate that TGA deteriorates the network efficiency of the theta frequency band. This effect might be related to the desynchronization between the anterior and posterior brain areas. Nausea 3 (14.29%) Hypertension 6 (28.57%) Diabetes 1 (4.76%) Hyperlipidemia 9 (42.86%) Hours from symptom onset to the initial DWI, median (interquartile range) 7 (5-9) Laterality of diffusion-weighted imaging lesion Left 8 (28.10%) Right 9 (42.86%) Bilateral 4 (19.05%) Location of diffusion-weighted imaging lesion Head 6 (28.57%) Body 11 (52.38%) Tail 5 (23.81%) Days from symptom onset to the EEG recording during the resolved stage, median (interquartile range) 147 (99-375) Values are presented as numbers (%) unless otherwise indicated.
doi:10.1371/journal.pone.0164884 pmid:27741293 pmcid:PMC5065218 fatcat:a5yoqqndkrdlvoa3diofld6h7a

Electrophysiological correlates of object-repetition effects: sLORETA imaging with 64-channel EEG and individual MRI

Myung-Sun Kim, Kyoung-Mi Jang, Huije Che, Do-Won Kim, Chang-Hwan Im
2012 BMC Neuroscience  
We investigated the electrophysiological correlates of object-repetition effects using an object categorization task, standardized low-resolution electromagnetic tomography (sLORETA), and individual magnetic resonance imaging. Sixteen healthy adults participated, and a total of 396 line drawings of living and non-living objects were used as stimuli. Of these stimuli, 274 were presented only once, and 122 were repeated after one to five intervening pictures. Participants were asked to categorize
more » ... the objects as living or non-living things by pressing one of two buttons. Results: The old/new effect (i.e., a faster response time and more positive potentials in response to repeated stimuli than to stimuli initially presented) was observed at 350-550 ms post-stimulus. The distributions of cortical sources for the old and new stimuli were very similar at 250-650 ms after stimulus-onset. Activation in the right middle occipital gyrus/cuneus, right fusiform gyrus, left superior temporal gyrus, and right inferior frontal gyrus was significantly reduced in response to old compared with new stimuli at 250-350, 350-450, 450-550, and 550-650 ms after stimulus-onset, respectively. Priming in response time was correlated with the electrophysiological priming at left parietal area and repetition suppression at left superior temporal gyrus in 450-550 ms. Conclusions: These results suggest processing of repeated objects is facilitated by sharpening perceptual representation and by efficient detection or attentional control of repeated objects.
doi:10.1186/1471-2202-13-124 pmid:23075055 pmcid:PMC3502408 fatcat:kg4pf2tinng4xmhk7pq4vsraqy

Result Analysis of Sea Trial Test for Offshore Fishing Boat Attached FRP Rudder
FRP 복합재료 방향타 장착 근해어선의 해상시운전시험 결과분석

Chung-Hwan Park, Ho-Yun Jang, Myung-Sik Park, Nam-Kyun Im
2013 한국해양공학회지  
Test area Busan ki-jang Wave height 0.5m Wind vel. 4.2m/s Dimension L 17.8m G/T 20 ton B 4.2m Fuel Capa. 1.8(L)×1.8(B) ×1.09(D)m D 1.72m Person 11 Engine Spe. 1,800 rpm × 380  ... 
doi:10.5574/ksoe.2013.27.6.112 fatcat:joyfeffdrbfb5awnkdjvs52fiy

Two Linear Methods for Camera Calibration and Their Applications to Augmented Reality and 3D Reconstruction [chapter]

Jang-Hwan Im, Ji-Hong Min, Hyung-Soo Ohk, Jong-Soo Choi
2003 Lecture Notes in Computer Science  
Im et al.  ... 
doi:10.1007/3-540-45103-x_83 fatcat:ogfytntbmzhlzhczbfohqihsvy

Health insurance system for hematologic diseases: what should we do?

Moon Ju Jang, Hyeon Jin Park, Sung-Soo Yoon, Je-Hwan Lee, Kyung-Duk Park, Seok-Jin Kim, Ho-Joon Im, Jin-Seok Kim, Jun-Ho Jang, Suk-Joong Oh, Hee-Soon Cho, Jae-Woo Song (+2 others)
2011 The Korean Journal of Hematology  
Although NHI generally does not cover rare, incurable diseases because of their rarity, there are approximately
doi:10.5045/kjh.2011.46.1.6 pmid:21461295 pmcid:PMC3065631 fatcat:6jgakgik4zakbewj3bs46edw3m

Pentacene-Based Low-Leakage Memory Transistor with Dielectric/Electrolytic/Dielectric Polymer Layers

Wonjun Choi, Seok Hwan Noh, D. K. Hwang, Jeong-M. Choi, Sungjin Jang, Eugene Kim, Seongil Im
2008 Electrochemical and solid-state letters  
We report on the pentacene memory thin-film transistors ͑TFTs͒ with a poly-4-vinylphenol ͑PVP͒/poly͑vinylidene fluoride/ trifluoroethylene͒ ͓P͑VDF/TrFE͔͒/PVP triple-layer gate insulator. The top PVP dielectric in the triple layer was intended to provide a smooth hydrophobic surface to ensure good crystalline growth of pentacene channel, while the bottom PVP was for leakage protection. The middle P͑VDF/TrFE͒ layer, known as ferroelectric material, revealed an electrolytic or ion movement
more » ... e rather than ferroelectric in our sandwich form of organic insulator. Our TFTs showed remarkably reduced leakage current, good memory window ͑large threshold voltage shift under slow gate-bias swing͒, and good field-effect mobility ͑0.2 cm 2 /V s͒. Retention time for the electrolytic memory effects was measured to be more than 10 4 s under a constant-read condition.
doi:10.1149/1.2822888 fatcat:3ednnfyho5fjpbbnrocbfho73e

Morphologic Changes of Zebrafish Melanophore after Intense Pulsed Light and Q-Switched Nd:YAG Laser Irradiation

Hwa Jung Ryu, Ji Min Lee, Hee Won Jang, Hae Chul Park, Im Joo Rhyu, Il-Hwan Kim
2016 Annals of Dermatology  
Recently, the pulse-in-pulse mode of intense pulsed light (IPL) has been used increasingly for the treatment of melasma. Objective: To observe the morphologic changes in the melanophore in adult zebrafish after irradiation with conventional and pulse-in-pulse IPL and Q-switched Nd:YAG (QSNY) laser. Methods: Adult zebrafish were irradiated with conventional and pulse-in-pulse mode of IPL. The conditions for conventional IPL were 3 mJ/cm 2 , 560 nm filter, and pulse widths of 7, 20, and 35 msec.
more » ... he pulse-in-pulse conditions were 3 mJ/cm 2 and on-time 1/off-time 2. The QSNY laser was used with the settings of 1,064 nm, 0.4 J/cm 2 , a 7 mm spot size, and one shot. Specimens were observed using a light microscope, a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a confocal microscope. Results: After conventional IPL irradiation with a 7 msec pulse width, melanophore breakage was observed using light microscopy. Under TEM, irradiation with conventional IPL for 7 msec and pulse-in-pulse IPL induced melanophore thermolysis with vacuolization. However, changes in the melanophore were not observed with 35 msec IPL. Under SEM, unlike the control and QSNY groups, IPL-irradiated zebrafish showed finger-like fusion in the protein struc-ture of scales. Specimens examined by a confocal microscope after conventional IPL irradiation showed a larger green-stained area on TUNEL staining than that after pulse-in-pulse mode IPL irradiation. Conclusion: Zebrafish irradiated with long pulse-IPL showed no morphologic changes using light microscopy, while morphological changes in melanophores were evident with use of TEM. Pulse-in-pulse mode IPL caused less damage than conventional IPL. (Ann Dermatol 28(6) 711∼717, 2016) -Keywords-Intense pulsed light, Melanophores, Zebrafish
doi:10.5021/ad.2016.28.6.711 pmid:27904270 pmcid:PMC5125952 fatcat:3upmgthswrez3bg7zvxyd7zzqm

Hybrid Polyline Simplification for GIS Vector Map Data Compression
GIS 벡터맵 데이터 압축을 위한 혼합형 폴리라인 단순화

Dae-Yeop Im, Bong-Joo Jang, Suk-Hwan Lee, Seong-Geun Kwon, Ki-Ryong Kwon
2013 Journal of Korea Multimedia Society  
Jang 등[11,12]은 웹 GIS 서비스 환경에서의 효율적인 전송과 저장을 위한 GIS 벡터맵 데이터 압축 기법을 제안하였고, 제안 기법은 폴리라인을 구성하고 있는 모든 64비트 좌표데이터를 이용한 공간영역에서의 에너지 집중 과정(SEC, spatial energy compaction)과 zlib[16] 압 축 라이브러리를 이용하여 압축한다.  ...  (a) 단순화율[%] 및 (b) 가중치 변화에 따른 단순화율과 면적오차(m 2 ) GIS 벡터맵 레이어 종류 원본 데이터 제안 방법(%) Jang 방법(%) 마산 철도 43 23(54.06) 28(64.97) 하천 5,145 2,117(41.15) 2,970(57.73) 도로 8,326 3,913(47.00) 4,861  ... 
doi:10.9717/kmms.2013.16.4.418 fatcat:fmmgnfioifdjlmnwl3u64ecevi

ZnO-based nonvolatile memory thin-film transistors with polymer dielectric/ferroelectric double gate insulators

Seok Hwan Noh, Wonjun Choi, Min Suk Oh, D. K. Hwang, Kimoon Lee, Seongil Im, Sungjin Jang, Eugene Kim
2007 Applied Physics Letters  
The authors report on the fabrication of a top-gate ZnO thin-film transistor ͑TFT͒ with a polymer dielectric/ferroelectric double-layer gate insulator that was formed on patterned ZnO through a sequential spin-casting process of 450-nm-thick poly-4-vinylphenol ͑PVP͒ and 200-nm-thick poly͑vinylidene fluoride/trifluoroethylene͒ ͓P͑VDF/TrFE͔͒. Compared to the single P͑VDF/TrFE͒ layer, double layer shows remarkably reduced leakage current with the aid of the PVP buffer. TFT with the PVP/P͑VDF/TrFE͒
more » ... double layer exhibits a field effect mobility of 0.36 cm 2 / V and a large memory hysteresis in the transfer characteristics due to the ferroelectric P͑VDF/TrFE͒. The retention of the device lasted over 2 h. Field effect transistors with ferroelectric gate insulators ͑FeFETs͒ have been extensively researched because of their nonvolatile memory retention and nondestructive readout. 1,2 Their memory effect originates from the ferroelectric polarization of the gate insulator which leads to modulation of the channel conductance. Inorganic materials such as lead zirconate titanate 3 and strontium bismuth tantalate 4 have been the focused materials for Si-based FeFET, requiring very high process temperatures ͑usually above 500°C͒ for good ferroelectric properties. Very recently, researchers study organic thin-film materials for the nonvolatile memory ͑NVM͒ applications, desiring the memory to be realized on plastic or glass substrates. 5,6 Poly͑vinylidene fluoride/trifluoroethylene͒ ͓P͑VDF/TrFE͔͒ copolymer is one of the attractive ferroelectric polymers for the NVM applications since it has a high remnant polarization ͑ϳ11.9 C/cm 2 ͒, 7 short switching time ͑ϳ1 ms͒, 8 and ease of fabrication in thin-film form by the solution process at a low temperature. However, the P͑VDF/TrFE͒ film usually shows large gate leakage current which deteriorates the performance of the FeFETs because TrFE in the middle of the chain can act as a leakage path. 7 In the present study, we have fabricated ZnO-based top-gate FeFETs which show a large memory window and good data retention properties without serious gate leakage current, inserting an additional poly-4-vinylphenol ͑PVP͒ layer between the P͑VDF/TrFE͒ layer and the active layer. Adopting inorganic ZnO channel, we could thus obtain the high value of field effect mobility as well. The glass ͑Corning 1737͒ substrate was cleaned with acetone, methanol, and de-ionized water, in that order. Then 150-nm-thick ZnO films were deposited at a low substrate temperature of 100°C by rf sputtering in a vacuum chamber ͑with base pressure of 1 ϫ 10 −6 and working pressure of 10 mTorr composed of the mixture of Ar: O 2 =6:1͒, and then Al source/drain electrodes were patterned by thermal evaporation. Spin casting was performed to cover the patterned ZnO structure with 450-nm-thick PVP layer, followed by a curing process at 175°C for 1 h in vacuum. Then, a 200-nm-thick film of P͑VDF/TrFE͒ 75/ 25 mol % copolymer was also coated by spin casting 6 wt % cyclohexanone solutions and was cured at 135°C for 2 h in air. Finally, Al top-gate electrode was deposited by thermal evaporation. Figure 1͑a͒ shows a schematic cross section of our device, which has a nominal channel length ͑L͒ of 90 m and a width/length ͑W / L͒ ratio of ϳ6. All current-voltage ͑I-V͒ or current density-electric field ͑J-E͒ characterizations were carried out with a semiconductor parameter analyzer ͑model HP 4155C, Agilent Technolo-gies͒ in the dark at room temperature. Capacitance-voltage ͑C-V͒ measurements were performed with a C-V meter ͑model HP 4284A, Agilent Technologies͒. Film thickness was determined by a surface profiler ͑Alpha-Step IQ͒. Figure 1͑b͒ shows the capacitance-voltage ͑C-V͒ and current density-electric field ͑J-E͒ ͑inset͒ characteristics of ferroelectric P͑VDF/TrFE͒ single insulator ͑200 nm thick͒, while Fig. 1͑c͒ displays those characteristics of our PVP ͑450-nm-thick dielectric͒/P͑VDF/TrFE͒ ͑200-nm-thick ferro-electric͒ double insulator as obtained from 300 m diameter Al/insulator/indium tin oxide structure. During the voltage sweeps from −20 to 20 V and vice versa, the capacitance of the 200-nm-thick P͑VDF/TrFE͒ film varied from 30.2 to 42.9 nF/ cm 2 showing the same peak value near −9 and 9 V. According to the capacitance data, the dielectric constant k FE of the P͑VDF/TrFE͒ film was estimated to be 6.8-9.7. The peaks of J-E curve also appeared at the same voltages, which shows the ferroelectric switching behavior of the P͑VDF/TrFE͒ film due to the displacement current. From the peak positions of the C-V and J-E curves, the coercive field ͑E c ͒ of our P͑VDF/TrFE͒ film was determined to be 0.45 MV/ cm. Then, based on the coercive field of P͑VDF/TrFE͒ and the following equation, 9 we could work out the coercive voltage ͑V c ͒ for 450-nm-thick PVP/ 200-nm-thick P͑VDF/TrFE͒ double layer. where k i ͑ϳ4.0͒ and k FE ͑ϳ9.7 for switching event͒ are the measured dielectric constants of the PVP and P͑VDF/TrFE͒ a͒
doi:10.1063/1.2749841 fatcat:kfu3uelij5efha6gafjmdc2sqm
« Previous Showing results 1 — 15 out of 445 results