사외이사의 독립성이 전략변화에 미치는 영향

정재승(Jeong JaeSeung),문철우(Moon ChulWoo),김상균(Kim Sang-Kyun) 한국인사관리학회 2016 조직과 인사관리연구 Vol.40 No.1

본 연구는 사외이사의 독립성이 기업 전략변화에 미치는 영향과 이들 두 변수 간의 관계에 있어서 과거 경영성과의 조절효과에 대해 분석하였다. 2006년부터 2008년까지 3개년의 시계열을 갖는 142개 국내 상장기업의 패널자료를 이용한 실증분석 결과, 사외이사의 독립성과 기업의 전략 변화 간에 통계적으로 유의미한 관계는 확인되지 않았다. 그러나 과거 경영성과는 이들 두 변수간의 관계에서 유의미한 조절효과를 가지고 있음을 확인하였다. 특히 과거 경영성과가 낮을수록 사외이사의 독립성과 전략변화 간의 정(+)의 관계를 확인하였다. 즉 경영성과가 낮은 상황에서 사외이사의 독립성이 전략변화에 정(+)의 영향을 미치는 것을 확인하였다. 본 연구결과는 글로벌 금융위기 이후 기업지배구조 개선에 대한 관심이 재차 높아지고 있고 경영환경 변화 및 기업 간 무한경쟁으로 인해 기업의 전략적 변화의 중요성이 증가하고 있는 시점에서 기업지배구조 메커니즘으로서 핵심적 역할을 담당하는 사외이사의 독립성이 기업의 전략 변화에 미치는 영향에 관해 실증하여 유의미한 결과를 도출하였다는 점에서 향후 바람직한 기업 지배구조 체제를 확립하고자 하는 기업의 경영실무나 유관기관의 정책업무에 유익한 참고자료가 될 수 있을 것으로 기대한다. The world economy experienced a global crisis in 2008. After this crisis, corporate governance have generated considerable attention in both the business and academic community. Outside directors are believed to be more effective means than other in corporate governance. Most of researches about outside directors have analyzed the relationship between outside directors and corporate performance from the prospective of outside directors’s control role. Outside directors are recognized as having the potential to influence strategic changes in corporate. However, there is considerable debate regarding the strategic role of outside directors. This paper examined the relationship between outside directors and corporate strategic changes from the prospective of service role. Using a random sample of 132 Korean firms over the 2006-2008. Our finding will draw attention to the need for the strategic role of outside directors.

세종 국가시범도시는 어떻게 스마트도시를 만들고 있는가?

정재승(Jaeseung Jeong) 한국정보과학회 2020 정보과학회지 Vol.38 No.6

뇌과학 방법론을 활용한 생활과학

정재승(Jaeseung Jeong) 한국생활과학회 2010 한국생활과학회 학술대회 Vol.2010 No.하계

공포의 신경 기저 회로 : 동물과 인간 대상 연구를 중심으로

백광열,정재승,박민선,채정호,Baek, Kwangyeol,Jeong, Jaeseung,Park, Min-Sun,Chae, Jeong-Ho 대한생물정신의학회 2008 생물정신의학 Vol.15 No.4

Objectives : The neural substrate of fear is thought to be highly conserved among species including human. The purpose of this review was to address the neural substrates of fear based on recent findings obtained from animal and human studies. Methods : Recent studies on brain regions related to fear, particularly fear conditioning in rodents and humans, were extensively reviewed. Results : This paper suggests high consistency in anatomical structure and physiological mechanisms for fear perception, response, learning and modulation in animals and humans. Conclusions : Fear is manifested and modulated by well conserved neural circuits among species interconnected with the amygdala, such as the hippocampus and the ventromedial prefrontal cortex. Further research is required to incorporate findings from animal studies into a better understanding of neural circuitry of fear in human in a translational approach.

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.

조현병 환자와 건강한 대조군에서 성별에 따른 뇌파 동시성의 차이

정혜민,이유상,김성수,김성균,정재승,오진석,이승연,김범준,장재승,Jung, Hye Min,Lee, Yu Sang,Kim, Seongsu,Kim, Seongkyun,Jeong, Jaeseung,Oh, Jin-Seok,Lee, Seungyeoun,Kim, Bum Joon,Chang, Jae Seung 대한생물정신의학회 2013 생물정신의학 Vol.20 No.4

Objectives Alteration of epigenetic effects of testosterone during early development was suggested as an ancillary mechanism for the genesis of schizophrenia. EEG coherence was thought to be a marker for cerebral laterality of which important determinant was testosterone during early development. We studied sex-related differences of EEG coherences between patients with schizophrenia and controls to examine the sex effects in the genesis of schizophrenia. Methods EEG was recorded in 35 patients with schizophrenia and 46 healthy controls in the eyes closed resting state. Pair-wise EEG coherences were calculated over delta, theta, alpha, beta and gamma frequency bands. To examine the differences of EEG coherence according to sex in each group, ANCOVA was performed using Statistical Analysis system (SAS, Ver 9.3) and R (Ver 2.15.2). Results Healthy control males showed more increased right intrahemispheric coherences than healthy control females in delta, theta, alpha and beta frequency bands. In patients with schizophrenia, this male dominant pattern in right intrahemispheric coherences was attenuated especially in alpha and beta bands. Healthy control females showed more increased interhemispheric coherences than healthy control males in delta, theta, beta and gamma frequency bands. In patients with schizophrenia, these female dominant patterns in interhemispheric coherences were attenuated especially in delta, theta, and beta bands, which were commonly observed in frontal to central areas. Conclusion Sex differences in resting EEG coherences were attenuated in schizophrenia patients. These results imply that sex-related aberrant cerebral lateralization might exist in patients with schizophrenia, which are partly due to sex hormones via epigenetic mechanisms.

조현병 환자에서 성별에 따른 검지 대 약지의 길이 비율과 뇌파 동시성의 관련성

최병하,이유상,한은선,김성균,정재승,이승연,김범준,Choi, Byungha,Lee, Yu Sang,Han, Eun-Seun,Kim, Seongkyun,Jeong, Jaeseung,Lee, Seungyeoun,Kim, Bum Joon 대한생물정신의학회 2014 생물정신의학 Vol.21 No.4

Objectives Prenatal testosterone is known to influence both cerebral laterality and 2nd to 4th digit ratio (2D : 4D). Epigenetic changes are thought to play some role in it. We studied sex-related differences between 2D : 4D and cerebral laterality in patients with schizophrenia and controls to examine the effects of prenatal testosterone in the development of schizophrenia. Methods Forty one men (18 schizophrenic patients and 23 controls) and 40 women (17 schizophrenic patients and 23 controls) were recruited from one psychiatric hospital in Korea. The 2D : 4D and electroencephalographic (EEG) coherence in 19 channels (66 pairs of interhemispheric coherence and 54 pairs of intrahemispheric coherence) were measured. The sex-related statistical analyses between 2D : 4D and EEG coherence in controls and patients with schizophrenia were performed using multiple regression. Results In male patients, the relationship between 2D : 4D and right intrahemispheric EEG coherence showed mainly positive correlation in delta and theta frequency bands, while it showed negative correlation in male controls. In female patients, the relationship between 2D : 4D and interhemispheric EEG coherence showed stronger positive correlation in alpha and beta frequency bands, while it showed weaker positive correlation in female controls. Conclusions Low prenatal testosterone may play certain roles in altered correlation between 2D : 4D and cerebral laterality in schizophrenia and the development of schizophrenia by epigenetic mechanism.

양극성장애 환자와 대조군에서 뇌파 코히런스의 성별 차이

유현주,이유상,안은숙,정동화,김성균,정재승,곽용태,이승연,You, Hyunju,Lee, Yu Sang,An, Eunsoog,Jeong, Donghwa,Kim, Seongkyun,Jeong, Jaeseung,Kwak, Yongtae,Lee, Seungyeoun 대한생물정신의학회 2015 생물정신의학 Vol.22 No.4

Objectives Sex hormones exposure during the prenatal period has an effect on cerebral lateralization. Male brains are thought to be more lateralized than female brains. Bipolar disorder was known to show abnormalities in cerebral laterality whose characteristics could be estimated by electroencephalography (EEG) coherences. We studied sex-related differences of EEG coherences between healthy controls and patients with bipolar disorder to examine the sex effects in the genesis of bipolar disorder. Methods Participants were 25 patients with bipolar disorder (11 male, 14 female) and 46 healthy controls (23 male, 23 female). EEG was recorded in the eyes closed resting state. To examine dominant EEG coherence associated with sex differences in both groups within five frequency bands (delta, theta, alpha, beta, and gamma) across several brain regions, statistical analyses were performed using analysis of covariance. Results Though statistically meaningful results were not found, some remarkable findings were noted. Healthy control females showed more increased interhemispheric coherences than control males in gamma frequency band. There were no differences in the intrahemispheric coherences between the healthy control males and females. In patients with bipolar disorder, female dominant pattern in interhemispheric coherences was attenuated compared with healthy control. Conclusions Sex differences of EEG coherences, which could be a marker for cerebral laterality, were attenuated in patients with bipolar disorder compared with healthy controls. These results imply that abnormal sex hormone exposure during early development might play some role in the pathogenesis of bipolar disorder.

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.

뚜렛 장애 남아에서 틱 억제시 대뇌 피질 정보 전달

홍현주,차민호,최강,황선희,소유경,주민경,남궁기,정재승 大韓神經精神醫學會 2007 신경정신의학 Vol.46 No.1

Objectives : Tourette's Disorder (TD) is a chronic neuropsychiathc disorder characterized by multiple motor and vocal tics with onset in childhood. The aim of this study was to ascertain the increased cortical information transmission in frontal area during tic suppression in drug naive boys with TD using new nonlinear analysis of EEGs, be called Transfer Entropy (TE) which can detect the directed exchange of information between two systems. Methods : Subjects were 11 drug naive boys with DSM-IV diagnosis of TD and 10 control boys. Clinical assessments were performed, and EEGs were recorded from 19 scalp loci of the international 10-20 systems. TE was estimated by EEG time-series data after noise reduction. TE difference between TD and control during resting state and between tic suppression and resting state in TD were investigated. Rcsults : Elevated TE was found in extensive channels, including frontal, central and temporal channels (F7, Fz, F8,Cz, C3, P3, T3, and T4) in resting state ofTourette's disorder compared to normal controls. Duhng tic suppression elevated TE was found in more extensive and asymmetrical channels especially prefrontal area (Fpl, Fp2, F3, Fz, F7, F8, Cz, C4, C5, T3, and T4). Conclusion : These findings suggest that pathogenesis of Tourette's disorder involve impaired cortical neuronal modulation in subcortical neural circuits. EEG analysis of TE may be a useful tool to investigation of cortical mechanism of psychiatric illness.