수면박탈이 각성 뇌파의 양수 리아프노프 지수에 미치는 효과에 관한 연구

김대진 ( Dai Jin Kim ),정재승 ( Jae Seung Jeong ),채정호 ( Jeong Ho Chae ),고효진 ( Hyo Jin Go ),김춘길 ( Choon Gil Kim ),김수용 ( Soo Yong Kim ),백인호 ( In Ho Paik ) 한국감성과학회 1997 연차 학술대회 논문집 Vol.1997 No.-

Sleep deprivation may affect the brain functions such as cognition and, consequently, dynamics of the EEG. We examined the effects of sleep deprivation on chaoticity of the EEG. Five volunteers were sleep-deprived over a period of 24 hours. They were checked by EEG during two days, the first day of baseline period and the second day of total sleep deprivation period. EEGs were recorded from 16 channels for nonlinear analysis. We employed a method of minimum embedding dimension to calculate the first positive Lyapunov exponent. For limited noisy data this algorithm was strikingly faster and more accurate than previous ones. Our results show that the sleep deprived volunteers had lower values of the first positive Lyapunov exponent at ten channels (Fp1, F4, F8, T4, T5, C3, C4, P3, P4, O1) compared with the values of baseline periods. These results suggested that sleep deprivation leads to decrease of chaotic activity in brain and impairment of the information processing in the brain. We suggested that nonlinear analysis of the EEG before and after sleep deprivation the role of sleep and the effects of sleep deprivation on the brain function.

주파수 가변 고속 디지털 MRI 모뎀 RF부 설계와 구현

김용철,박현대,김대진 전남대학교 전자통신기술연구소 2001 전자통신기술논문지 Vol.4 No.1

In this paper, we designed and made RF block of variable frequency digital modem for high speed MIRI system that can support not only multi-nuclei system but also any magnetic intensity(1.0T~3.0T). We executed simulation of fixed frequency digital modem using fixed band pass filter(BPF), variable frequency digital modem using variable band pass filter(tunable filter). Based on these simulations, variable band pass filter(tunable filter) named Micropole is ordered and manufactured. We designed and made RF block of variable frequency digital modem for high speed MRI system using variable band pass filter(tunable filter). And then we tested this board using PC and function generator and observed the output spectrum using spectrum analyzer. These spectrums are very clear and wide bandwidth about 500KHz and the level of main spectrum is 60~70dB more than harmonics or spurious. This difference of level is available for MRI system.

매개 모형을 통하여 고찰한 우울과 주의력결핍 과잉행동장애, 인터넷 게임장애 사이의 관계

이선규,김대진,조현,Lee, Seon-Gyu,Kim, Dai-Jin,Cho, Hyun 대한생물정신의학회 2019 생물정신의학 Vol.26 No.2

Objectives Internet gaming disorder (IGD) is associated with attention deficit/hyperactivity disorder (ADHD) or depression etc. We tried to examine the mediating effects of depression in the relationship between ADHD and IGD. Methods This study was conducted on 2000 people who participated in on-line survey among 14-39 year-old men and women in 2017. And we clarified the relationship among IGD, ADHD, and depression and tested the mediation model. The mean and standard deviation of the main variables were calculated and correlation analysis was performed to confirm the relationship among the main variables. In order to test the mediating effect of depression on the relationship between ADHD and IGD, the structural equation model was implemented using AMOS 21 (IBM). Results There were significant correlations among the variables; IGD, ADHD and depression. Depression had a mediating effect 0.23 (95% confidence interval : 0.17-0.28) in the relationship between IGD and ADHD. Conclusions This study showed that depression can mediate ADHD and IGD. Therefore, the evaluation and management of depression and ADHD should be included in the diagnosis and treatment of IGD.

중독 정신 병리의 이해 : 뇌영상 연구를 중심으로

민정아,김대진,Min, Jung-Ah,Kim, Dai-Jin 대한생물정신의학회 2011 생물정신의학 Vol.18 No.2

Substance addiction is a chronically relapsing disorder that has been characterized by a vicious cycle composed of intoxication, craving/anticipation, withdrawal, and response inhibition/bingeing. Here we summarize the findings from neuroimaging studies in addiction according to these behavioral components and suggest the integrated neurobiological model of drug addiction and related brain correlates. The roles of various prefrontal regions, thalamus, memory circuit, anterior cingulated, and insula were also suggested in addition to those of classical mesolimbic dopaminergic system and its responsivity. Limited studies of behavioral addiction demonstrated a similarity with substance addiction on the neurobiological basis. Based on the current understanding of neurobiology of addiction, further researches on interactions of behavioral components and their brain correlates, behavioral addiction, and therapeutic applications will be desired.

알츠하이머형 치매 환자 뇌파의 비선형 역동 분석 - 상관차원을 이용한 예비적 연구 -

채정호,김대진,정재승,김수용,고효진,백인호,Chae, Jeong-Ho,Kim, Dai-Jin,Jeong, Jaeseung,Kim, Soo Yong,Go, Hyo Jin,Paik, In-Ho 대한생물정신의학회 1997 생물정신의학 Vol.4 No.1

치매에서의 뇌파 연구는 주로 주파수 분석과 지형화 분석을 이용하여 정량화하는 것을 위주로 진행되어 왔으나 이러한 선형적 분석은 뇌파와 같이 복잡한 신호를 분석하는 것에는 한계가 있었다. 최근 새로운 패러다임인 카오스이론에 근거를 두고 뇌파를 비선형적으로 측정하는 방법이 소개되고 있다. 본 연구는 알츠하이머형 치매환자의 뇌파 신호를 상관차원을 이용하여 비선형적으로 분석하는 것이 가능한가를 알아보고 그 결과를 대조군과 비교해보기 위하여 시도되었다. 3명의 알츠하이머형 치매 환자와 3명의 대조군에서 뇌파 신호를 받아 디지털 화한 후에 비선형분석법 중 하나인 상관차원 값을 계산하였다. 전체 15개의 전극부위 중 3곳을 제외하고는 모든 전극과 두뇌 영역별, 반구별 분석 모두에서 알츠하이머형 치매군의 상관차원값이 유의하게 낮았다. 본 연구 결과는 알츠하이머형 치매 환자에서 카오스 이론을 이용한 비선형적 전기신경생리학적 분석으로 알아낼 수 있는 두뇌의 복합성, 즉 두뇌의 카오스적 성상이 감소되어 있다는 것을 의미하며 향후 뇌파의 비선형적 분석이 두뇌 기능을 조사하는 데에 유용한 새로운 방법이 될 가능성이 있다는 것을 시사한다. The changes of electroencephalogram(EEG) in patients with dementia are most commonly studied by analyzing power or magnitude in certain traditionally defined frequency bands. However because of the absence of an identified metric which quantifies the complex amount of information, there are many limitations in using such a linear method. According to chaos theory, irregular signals of EEG can also result from low dimensional deterministic chaos. Chaotic nonlinear dynamics in the EEG can be studied by calculating the correlation dimension. The authors have analyzed EEG epochs from three patients with dementia of Alzheimer type and three matched control subjects. The multichannel correlation dimension is calculated from EEG epochs consisting of 15 channels with 16,384 data points per channel. The results showed that patients with dementia of Alzheimer type had significantly lower correlation dimension than non-demented controls on 12 channels. Topographic analysis showed that the correlation dimensions were significantly lower in patients with Alzheimer's disease on frontal, temporal, central, and occipital head regions. These results show that brains of patients with dementia of Alzheimer type have a decreased complexity of electrophysiological behavior. We conclude that the nonlinear analysis such as calculating correlation dimension can be a promising tool for detecting relative changes in the complexity of brain dynamics.

리아프노프 지수를 이용한 알쯔하이머형 치매 환자 뇌파의 비선형 역동 분석을 위한 예비연구

채정호,김대진,최성빈,박원명,이정태,김광수,정재승,김수용,Chae, Jeong-Ho,Kim, Dai-Jin,Choi, Sung-Bin,Bahk, Won-Myong,Lee, Chung Tai,Kim, Kwang-Soo,Jeong, Jaeseung,Kim, Soo-Yong 대한생물정신의학회 1998 생물정신의학 Vol.5 No.1

치매에서의 뇌파 연구는 주로 주파수 분석과 지형화 분석을 이용하여 정량화하는 것을 위주로 진행되어 왔으나, 이러한 선형적 분석은 뇌파와 같이 복잡한 신호를 분석하는 것에는 한계가 있었다. 최근 새로운 패러다임인 카오스 이론에 근거를 두고 뇌파를 비선형적으로 측정하는 방법이 소개되고 있다. 본 연구는 알쯔하이머형 치매 환자의 뇌파 신호를 최대 양수 리아프노프 지수를 이용하여 비선형적으로 분석하는 것이 가능한 가를 알아보고 그 결과를 대조군과 비교해보기 위하여 시도되었다. 3명의 알쯔하이머형 치매 환자와 3명의 대조군에서 뇌파 신호를 받아 디지털화한 후에 비선형 분석법 중 하나인 최대 양수 리아프노프 지수를 산출하였다. 알쯔하이머형 치매군은 전체 15개의 전극 부위 중 8곳의 전극 부위에서 대조군에 비하여 유의하게 낮은 최대 양수 리아프노프 지수를 나타내었다. 각 두뇌 영역별 및 반구별 분석에서도 알쯔하이머형 치매군이 대조군에 비하여 전 두뇌 영역에서 최대 양수 리아프노프 지수가 유의하게 낮았다. 이에 따라 알쯔하이머형 치매 환자의 뇌파를 비선형적 분석하여 조사한 이들 두뇌의 카오스적 성상이 감소되어 있다는 것을 확인할 수 있었다. 이 결과는 향후 뇌파의 비선형적 분석인 리아프노프 지수 산출이 두뇌 기능을 조사하는 데에 유용한 새로운 방법이 될 가능성이 있다는 것을 시사한다. The changes of electroencephalogram(EEG) in patients with dementia of Alzheimer's type are most commonly studied by analyzing power or magnitude in traditionally defined frequency bands. However because of the absence of an identified metric which quantifies the complex amount of information, there are many limitations in using such a linear method. According to the chaos theory, irregular signals of EEG can be also resulted from low dimensional deterministic chaos. Chaotic nonlinear dynamics in the EEG can be studied by calculating the largest Lyapunov exponent($L_1$). The authors have analyzed EEG epochs from three patients with dementia of Alzheimer's type and three matched control subjects. The largest $L_1$ is calculated from EEG epochs consisting of 16,384 data points per channel in 15 channels. The results showed that patients with dementia of Alzheimer's type had significantly lower $L_1$ than non-demented controls on 8 channels. Topographic analysis showed that the $L_1$ were significantly lower in patients with Alzheimer's disease on all the frontal, temporal, central, and occipital head regions. These results show that brains of patients with dementia of Alzheimer's type have a decreased chaotic quality of electrophysiological behavior. We conclude that the nonlinear analysis such as calculating the $L_1$ can be a promising tool for detecting relative changes in the complexity of brain dynamics.

양성 및 음성 정신분열증 환자 뇌파의 비선형 역동 분석

채정호,박이진,김대진,정재승,김수용,김광수,Chae, Jeong-Ho,Pak, E-Jin,Kim, Dai-Jin,Jeong, Jae-Seung,Kim, Soo-Yong,Kim, Kwang-Soo 대한수면의학회 1998 수면·정신생리 Vol.5 No.2

연구배경 : 양성 및 음성 정신분열병 환자간의 뇌파를 비선형적으로 분석하고 그 결과를 대조군과 비교하여 뇌파의 비선형 분석을 통한 정신분열병의 병태생리를 이해하기 위하여 양성 정신분열병 환자 8명, 음성 정신분열병 환자 9명과 정상 대조군 8명을 대상으로 하여 16전극에서 뇌파를 기록하여 비선형 분석을 시행하였다. 결과 : 좌측측두부 최대 양수 리아프노프 지수 값이 음성 정신분열병군에서 양성 정신분열병군과 정상 대조군에 비하여 유의하게 낮았으며, 일부 전극에서 양성증상은 좌측 두뇌의 카오스적 성상과 정상관이 있었으며 우측두뇌의 카오스적 성상과는 역상관이 있었다. 결론 : 본 연구결과를 통하여 정신분열병 환자의 두뇌 기능을 조사하는 데에 있어서 카오스적 역동을 응용한 뇌파분석이 임상적 유용성이 있음을 알 수 있었으며, 임상적 변인을 잘 통제한 연구가 필요하다는 것을 확인할 수 있었다. Objectives : The hypothesis that the brain is a nonlinear dynamical system exhibiting deterministic chaos has offered new perspectives to the investigation of information processing in the brain of schizophrenic patients. It seemed worthwhile to estimate nonlinear measures of the electroencephalogram (EEG) in positive and negative schizophrenics, because nonlinear measures might serve as indicators of the specific brain function in schizophrenia according to specific psychopathologies. Method : Previous studies which estimated the chaoticity in the brain of schizophrenia with nonlinear methods recorded the EEGs at limited electrodes, so we tried to record EEGs from 16 channels for nonlinear analysis in 8 positive and 9 negative schizophrenics and 8 healthy control subjects. We employed a new method to calculate the nonlinear invariant measures. For limited noisy data, this algorithm was strikingly faster and more accurate than previous ones. Results : Our results showed that the patients with negative schizophrenia had lower the first positive Lyapunov exponents ($L_1$) than the positive schizophrnics and control subjects at $T_3$ lead. Positive symptoms were positively correlated with $L_1$ in $C_3,\;O_1$ leads, and negatively correlated with $C_4$ lead. Conclusion : These results suggest that if clinical variables such as psychopathology or neuroleptic medications would be well controlled, the nonlinear analysis of the EEGs in patients with schizophrenia seems to be a useful tool in analyzing EEG data to explore the neurodynamics.

유전 알고리즘에 기반한 퍼지 벌레 검색과 자율 적응 최소-최대 군집화를 이용한 영상 영역화

하성욱,강대성,김대진,Ha, Seong-Wook,Kang, Dae-Seong,Kim, Dai-Jin 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.12

본 논문에서는 퍼지 벌레 검색과 최소-최대 군집화 알고리즘에 기반한 영상 영역화 기법을 제안한다. 전체 영상에서 에지 정보는 픽셀들의 공간 관계를 포함하게 되며, 이를 위해 목적 함수들의 인자를 조정하여 퍼지 벌레의 행동을 정의하며, 에지 정보를 검사하는 방법으로 퍼지 벌레값과 최소-최대 노드를 이용한다. 에지 추출을 사용하는 현재의 영역화 방법들은 수학적 모델에 기반한 매스크 정보를 필요로 하며, 매스크 연산으로 인하여 수행 시간도 많이 걸리게 된다. 반면에, 제안하는 알고리즘은 퍼지 벌레의 검색에 따라 단일 연산을 수행하게 된다. 제안하는 알고리즘에서 필요한 범위의 크기를 스스로 결정하고 빠르고 강력한 계산을 수행하기 위해 최적해를 찾는 유전 알고리즘을 도입하고자 한다. 추가적으로, 영상의 그레이-히스토그램에서 퍼지 검색과 군집화를 수행하기 위해 유전 알고리즘을 사용하는 유전 퍼지 벌레 검색과 유전 최소-최대 군집화가 제안된다. 시뮬레이션 결과는 제안된 알고리즘이 히스토그램을 사용하여 적응적으로 양자화되며, 계산 시간과 메모리를 적게 요구하는 단일 검색 방법을 수행한다는 것을 보여준다. An image segmentation approach based on the fuzzy worm searching and MIN-MAX clustering algorithm is proposed in this paper. This algorithm deals with fuzzy worm value and min-max node at a gross scene level, which investigates the edge information including fuzzy worm action and spatial relationship of the pixels as the parameters of its objective function. But the conventional segmentation methods for edge extraction generally need the mask information for the algebraic model, and take long run times at mask operation, whereas the proposed algorithm has single operation according to active searching of fuzzy worms. In addition, we also propose both genetic fuzzy worm searching and genetic min-max clustering using genetic algorithm to complete clustering and fuzzy searching on grey-histogram of image for the optimum solution, which can automatically determine the size of ranges and has both strong robust and speedy calculation. The simulation results showed that the proposed algorithm adaptively divided the quantized images in histogram region and performed single searching methods, significantly alleviating the increase of the computational load and the memory requirements.

스트롱암 기반의 DTV 트랜스포트 스트림 발생기 설계 및 구현

박현대(Hyun Dai Park),장용석(Yong Seok Jang),최효정(Hyo Jung Choi),김대진(Dae Jin Kim) 대한전자공학회 2002 대한전자공학회 학술대회 Vol.2002 No.11

Phentermine 및 Phendimetrazine으로 유발된 정신병적 장애 및 양극성 장애 증례군 연구

김수영,김태석,김대진,채정호,이창욱,주수현,Kim, Soo Young,Kim, Tae-Suk,Kim, Dai-Jin,Chae, Jeong-Ho,Lee, Chang Uk,Joo, Soo Hyun 대한생물정신의학회 2022 생물정신의학 Vol.29 No.1

Objectives Recently, weight loss has emerged as a national concern in South Korea, and this has resulted in an increase in the frequency of use of central nervous system (CNS)-stimulating appetite suppressants. This study aimed to collect cases of psychotic disorders and bipolar disorders triggered by phentermine and phendimetrazine and explore the clinical features and courses. Methods In this retrospective study, we analyzed the electronic medical records of patients and selected eight patients who developed psychotic symptoms and manic symptoms for the first time after taking phentermine and phendimetrazine. All cases were reviewed, and their clinical features and course were summarized. Results All eight patients developed psychotic symptoms, and one had accompanying manic symptoms. The final diagnosis was appetite-suppressant-induced psychotic disorder in four patients, schizophrenia in three, and appetite-suppressant-induced bipolar disorder in one. In addition, three patients were diagnosed as having substance-use disorder. The key psychotic symptoms of these patients were hallucinations and paranoia. Conclusions These case findings suggest that phentermine and phendimetrazine can cause psychotic disorder, bipolar disorder, or substance use disorder and that medical professionals and the public should practice caution when prescribing and using these drugs.