우울증 여부에 따른 경도인지장애 환자의 신경심리학적 특징 비교

정광석(Kwang Seok Jeong),안준호(Joon Ho Ahn),방수영(Soo Young Bhang),최순호(Soon Ho Choi),김성윤(Seong Yoon Kim) 대한노인정신의학회 2012 노인정신의학 Vol.16 No.2

Objectives:The depression in the elderly often accompany with cognitive decline and the mild cognitive impairment (MCI) commonly accompany with depressive symptoms. This study was performed to compare the differences in neuropsychological characteristics between the MCI without depression and the MCI with depression. Methods:The subjects for this study were 366 MCI patient who enrolled through ‘Clinical Research Center for Dementia of South Korea (CREDOS) study’ gathered between December, 2005 and February, 2011. We divided the MCI patient into non-de-pressed group (n=187) and depressed group (n=179), and evaluated each cognitive domain with the Seoul Neuropsychological Screening Battery (SNSB) and analyzed the two group. Results:In the depressed group compared to the non-depressed group, Korean version of Mini-mental State Examination (K-MMSE) scores were lower (p<0.05), and Instrumental Activities of Daily Living (I-ADL) impairment was pronounced (p<0.05). In SNSB, the test scores of the two groups had similar levels on memory (p=0.403), language domain (p=0.098). But the test scores on attention (p<0.05), visuospatial function (p<0.05), executive function (p<0.05) domain in depression group was sig-nificantly lower than in non-depression group. Conclusion:This study shows differences in the clinical feature and neuropsychologic characteristics between the two differ-ent situations. MCI subjects with coexisting depression showed severer cognitive decline and had multiple cognitive domain im-pairment rather than single memory domain impairment.

Low-Frequency Noise 측정을 통한 Bottom-Gated ZnO TFT의 문턱전압 불안정성 연구

정광석,김영수,박정규,양승동,김유미,윤호진,한인식,이희덕,이가원,Jeong, Kwang-Seok,Kim, Young-Su,Park, Jeong-Gyu,Yang, Seung-Dong,Kim, Yu-Mi,Yun, Ho-Jin,Han, In-Shik,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.7

Low-frequency noise (1/f noise) has been measured in order to analyze the Vth instability of ZnO TFTs having two different active layer thicknesses of 40 nm and 80 nm. Under electrical stress, it was found that the TFTs with the active layer thickness of 80 nm shows smaller threshold voltage shift (${\Delta}V_{th}$) than those with thickness of 40 nm. However the ${\Delta}V_{th}$ is completely relaxed after the removal of DC stress. In order to investigate the cause of this threshold voltage instability, we accomplished the 1/f noise measurement and found that ZnO TFTs exposed the mobility fluctuation properties, in which the noise level increases as the gate bias rises and the normalized drain current noise level($S_{ID}/{I_D}^2$) of the active layer of thickness 80 nm is smaller than that of active layer thickness of thickness 40 nm. This result means that the 80 nm thickness TFTs have a smaller density of traps. This result correlated with the physical characteristics analysis performmed using XRD, which indicated that the grain size increases when the active layer thickness is made thicker. Consequently, the number of preexisting traps in the device increases with decreasing thickness of the active layer and are related closely to the $V_{th}$ instability under electrical stress.

Atomic Layer Deposition으로 증착된 Al-doped ZnO Film의 전기적, 구조적 및 광학적 특성 분석

임정수,정광석,신홍식,윤호진,양승동,김유미,이희덕,이가원,Lim, Jung-Soo,Jeong, Kwang-Seok,Shin, Hong-Sik,Yun, Ho-Jin,Yang, Seung-Dong,Kim, Yu-Mi,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.6

Al-doped ZnO film on glass substrate is deposited by ALD in low temperature, using 4-step process (DEZ-$H_2O$-TMA-$H_2O$). To find out the optimal film condition for TCO material, we fabricate Al-doped ZnO films by increasing Al doping concentration at $100^{\circ}C$, so that the Al-doped film of 5 at% shows the lowest resistivity ($1.057{\times}10^{-2}{\Omega}{\cdot}cm$) and the largest grain size (38.047 nm). Afterwards, the electrical and physical characteristics in Al-doped films of 5 at% are also compared in accordance with increasing deposition temperature. All the films show the optical transmittance over 80% and the film deposited at $250^{\circ}C$ demonstrates the superior resistivity ($1.237{\times}10^{-4}{\Omega}{\cdot}cm$).

Al Doped ZnO층 적용을 통한 ZnO 박막 트랜지스터의 전기적 특성과 안정성 개선

엄기윤,정광석,윤호진,김유미,양승동,김진섭,이가원,Eom, Ki-Yun,Jeong, Kwang-Seok,Yun, Ho-Jin,Kim, Yu-Mi,Yang, Seung-Dong,Kim, Jin-Seop,Lee, Ga-Won 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.5

Recently, ZnO based oxide TFTs used in the flexible and transparent display devices are widely studied. To apply to OLED display switching devices, electrical performance and stability are important issues. In this study, to improve these electrical properties, we fabricated TFTs having Al doped Zinc Oxide (AZO) layer inserted between the gate insulator and ZnO layer. The AZO and ZnO layers are deposited by Atomic layer deposition (ALD) method. I-V transfer characteristics and stability of the suggested devices are investigated under the positive gate bias condition while the channel defects are also analyzed by the photoluminescence spectrum. The TFTs with AZO layer show lower threshold voltage ($V_{th}$) and superior sub-threshold slop. In the case of $V_{th}$ shift after positive gate bias stress, the stability is also better than that of ZnO channel TFTs. This improvement is thought to be caused by the reduced defect density in AZO/ZnO stack devices, which can be confirmed by the photoluminescence spectrum analysis results where the defect related deep level emission of AZO is lower than that of ZnO layer.

저온 다결정 실리콘 박막 트랜지스터의 비정상적인 Hump 현상 분석

김유미,정광석,윤호진,양승동,이상율,이희덕,이가원,Kim, Yu-Mi,Jeong, Kwang-Seok,Yun, Ho-Jin,Yang, Seung-Dong,Lee, Sang-Youl,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.11

In this paper, we investigated an anomalous hump phenomenon under the positive bias stress in p-type LTPS TFTs. The devices with inferior electrical performance also show larger hump phenomenon. which can be explained by the sub-channel induced from trapped electrons under thinner gate oxide region. We can confirm that the devices with larger hump have larger interface trap density ($D_{it}$) and grain boundary trap density ($N_{trap}$) extracted by low-high frequency capacitance method and Levinson-Proano method, respectively. From the C-V with I-V transfer characteristics, the trapped electrons causing hump seem to be generated particularly from the S/D and gate overlapped region. Based on these analysis, the major cause of an anomalous hump phenomenon under the positive bias stress in p-type poly-Si TFTs is explained by the GIDL occurring in the S/D and gate overlapped region and the traps existing in the channel edge region where the gate oxide becomes thinner, which can be inferred by the fact that the magnitude of the hump is dependent on the average trap densities.

TCAD 시뮬레이션을 이용한 Fin형 SONOS Flash Memory의 모서리 효과에 관한 연구

양승동,오재섭,윤호진,정광석,김유미,이상율,이희덕,이가원,Yang, Seung-Dong,Oh, Jae-Sub,Yun, Ho-Jin,Jeong, Kwang-Seok,Kim, Yu-Mi,Lee, Sang-Youl,Lee, Hee-Deok,Lee, Ga-Won 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.2

Fin-type SONOS (silicon-oxide-nitride-oxide-silicon) flash memory has emerged as novel devices having superior controls over short channel effects(SCE) than the conventional SONOS flash memory devices. However despite these advantages, these also exhibit undesirable characteristics such as corner effect. Usually, the corner effect deteriorates the performance by increasing the leakage current. In this paper, the corner effect of fin-type SONOS flash memory devices is investigate by 3D Process and device simulation and their electrical characteristics are compared to conventional SONOS devices. The corner effect has been observed in fin-type SONOS device. The reason why the memory characteristic in fin-type SONOS flash memory device is not improved, might be due to existing undesirable effect such as corner effect as well as the mutual interference of electric field in the fin-type structure as reported previously.

SONOS 플래시 메모리 소자의 구조와 크기에 따른 특성연구

양승동,오재섭,박정규,정광석,김유미,윤호진,최득성,이희덕,이가원,Yang, Seung-Dong,Oh, Jae-Sub,Park, Jeong-Gyu,Jeong, Kwang-Seok,Kim, Yu-Mi,Yun, Ho-Jin,Choi, Deuk-Sung,Lee, Hee-Deok,Lee, Ga-Won 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.9

In this paper, Fin-type silicon-oxide-nitride-oxide-silicon (SONOS) flash memory are fabricated and the electrical characteristics are analyzed. Compared to the planar-type SONOS devices, Fin-type SONOS devices show good short channel effect (SCE) immunity due to the enhanced gate controllability. In memory characteristics such as program/erase speed, endurance and data retention, Fin-type SONOS flash memory are also superior to those of conventional planar-type. In addition, Fin-type SONOS device shows improved SCE immunity in accordance with the decrease of Fin width. This is known to be due to the fully depleted mode operation as the Fin width decreases. In Fin-type, however, the memory characteristic improvement is not shown in narrower Fin width. This is thought to be caused by the Fin structure where the electric field of Fin top can interference with the Fin side electric field and be lowered.

Hafnium Oxide를 Trapping Layer로 적용한 Fin-Type SOHOS 플래시 메모리 특성연구

박정규,오재섭,양승동,정광석,김유미,윤호진,한인식,이희덕,이가원,Park, Jeong-Gyu,Oh, Jae-Sub,Yang, Seung-Dong,Jeong, Kwang-Seok,Kim, Yu-Mi,Yun, Ho-Jin,Han, In-Shik,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.6

In this paper, the electrical characteristics of Fin-type SONOS(silicon-oxide-nitride-oxide-silicon) flash memory device with different trapping layers are analyzed in depth. Two kinds of trapping layers i.e., silicon nitride($Si_3N_4$) and hafnium oxide($HfO_2$) are applied. Compared to the conventional Fin-type SONOS device using the $Si_3N_4$ trapping layer, the Fin-type SOHOS(silicon-oxide-high-k-oxide-silicon) device using the $HfO_2$ trapping layer shows superior program/erase speed. However, the data retention properties in SOHOS device are worse than the SONOS flash memory device. Degraded data retention in the SOHOS device may be attributed to the tunneling leakage current induced by interface trap states, which are supported by the subthreshold slope and low frequency noise characteristics.

깊이 카메라를 활용한 숄더 프레스 동작의 신뢰도 및 정확도 검증

김성민 ( Sung-min Kim ),정광석 ( Kwang-seok Jeong ),이미소 ( Mi-so Lee ),김보경 ( Bo-kyung Kim ),김지인 ( Ji-in Kim ),문제헌 ( Je-heon Moon ),김석범 ( Suk-bum Kim ) 한국융합과학회 2022 한국융합과학회 국제학술대회자료집 Vol.2022 No.0

목적: 본 연구의 목적은 깊이 카메라를 활용하여 숄더 프레스 동작의 운동학적 변인을 추출하고 이를 적외선카메라와의 비교를 통한 데이터의 신뢰도와 정확도를 검증하는데 있다. 과정: 충청북도 청주시 소재 H대학에서 주 2회 이상 웨이트 트레이닝을 하는 20대 일반 남녀 학생 53명(남: 42명, 여: 11명)을 대상으로 숄더프레스 동작을 실시하였다. 깊이 카메라(D415, Intel) 데이터는 3차원 동작분석 장비인 적외선 카메라(Miqus M3, Qualisys)에서 추출된 변인들을 기준으로 신뢰도 및 정확도를 분석하였고 총 1,272회의 데이터를 수집하여 분석하였다. 두 종류의 카메라에서 추출된 위치좌표 데이터를 통해 각각 인체의 관절각도와 각속도를 산출하였고 신뢰도 분석을 위한 피어슨 상관계수, 정확도 분석을 위한 절대평균 제곱근 오차와 최대 굴곡/신전 각도 및 각속도를 사용하여 분석하였다. 결과: 피어슨 상관계수 분석 결과 좌/우측 팔꿈치 관절각도는 각각 0.969, 0.973, 어깨관절은 각각 0.881, 0.977로 나타났다. 좌/우측 팔꿈치 관절각속도는 0.899, 0.888으로 나타났고, 어깨관절은 0.848, 0.901으로 나타났다. 절대평균 제곱근 오차에서는 좌/우측 팔꿈치관절은 9.587, 9.177 deg, 어깨관절은 14.899, 9.927 deg로 나타났다. 좌/우측 팔꿈치 관절각속도는 50.209, 50.369 deg/s, 어깨관절은 41.556, 44.459 deg/s의 차이가 나타났다. 좌/우측 무릎관절은 각각 0.423, 1.909 deg/s와 엉덩관절은 1.909, 2.034 deg/s가 나타났다. 최대/최소 각도 차이는 대부분 관절에서 통계적인 차이가 나타났고(팔꿈치 좌측: 굴곡 - p = .014, 신전 - p = .000 / 우측: 신전 - p = .021; 어깨 좌측: 굴곡 - p = .000 / 우측: 굴곡 - p = .000, 신전 - p = .000; 엉덩이 좌/우측 굴곡/신전: p = 0.000; 무릎 좌측: 굴곡 - p = .002, 신전 - p = .003 / 우측: 굴곡 - p = .012, 신전 - p = .026) 각속도의 경우 무릎관절을 제외하고 팔꿈치, 어깨, 엉덩관절에서 통계적으로 유의한 차이가 나타났다(p = .000). 결론: 깊이 카메라와 적외선 카메라로 분석한 숄더 프레스 동작의 패턴은 유사한 결과를 보였지만 절대적인 크기를 비교한 각도와 각속도에서는 통계적인 차이가 나타났다. 따라서 깊이 카메라는 움직임 패턴을 인식하는데 활용이 가능할 것으로 판단되며, 정밀 동작에 대한 평가는 조심스럽게 접근해야 할 것으로 보인다. 추후 연구에서는 정상과 비정상 동작을 수집한 후 자동으로 분류하는 알고리즘을 개발하여 실내 트레이닝장의 이용자 안전사고를 예방 측면에서 활용되길 기대한다. Purpose: The purpose of this study is to identify the accuracy and reliability of the kinematic data of the depth camera based on the infrared camera data for shoulder press. Method: A total of 53 male(n = 42) and female(n = 11) healthy students participated in this study. Depth camera (D415, Intel) data were analyzed for reliability and accuracy based on variables extracted from infrared cameras (Miqus M3, Qualisys), and a total of 1,272 data were collected. Angle and angular velocity were calculated from position data. The analysis used the Pearson correlation coefficient for reliability analysis, Root Mean Square Error(RMSE) for accuracy analysis, and max/min angle and angular velocity difference between the two cameras. Result: The reliability analysis through pearson correlation between the two cameras showed high reliability of the left and right elbow(angle: left - 0.969, right - 0.969; angular velocity: left - 0.899, right - 0.888) and shoulder joint(angle: left - 0.881, right - 0.977) for angle and angular velocity(elbow: left - 0.969, right - 0.969; shoulder: 0.848, Right: 0.901). In RMSE, the left/right elbow for angle and angular velocity appeared 9.587/9.177 deg, 50.209, 50.369 deg/s, and the shoulder joint appeared 14.899, 9.927 deg, 41.556, 44.459 deg/s, respectively. The maximum/minimum angle difference was statistically different in most joints(left elbow: flexion - p = .014, extension - p = .000 / right: extension - p = .021; left shoulder: flexion - p = .000 / right: flexion - p = .000, extension - p = .000; left/right hip flexion/extension: p = 0.000; left knee: flexion - p = .002, extension - p = .003 / right: flexion - p = .012, extension - p = .026). The angular velocity was statistically significant in the elbow, shoulder, and hip joints, except for the knee joint(p = .000). Conclusion: The pattern of shoulder press analyzed by the depth camera and the infrared camera were similar, but statistical differences were found in joint angle and angular velocity of absolute value. Therefore, the depth camera can be used to analyze movement patterns, and precise movements should be evaluated carefully. In future studies, developing an algorithm that automatically classifies normal and abnormal movement is necessary. This technology is expected to be used to prevent safety accidents at indoor sports facilities.

산화막과 질화막 위에 제작된 3D SONOS 다층 구조 플래시 메모리소자의 1/f 잡음 특성 분석

이상율,오재섭,양승동,정광석,윤호진,김유미,이희덕,이가원,Lee, Sang-Youl,Oh, Jae-Sub,Yang, Seung-Dong,Jeong, Kwang-Seok,Yun, Ho-Jin,Kim, Yu-Mi,Lee, Hi-Deok,Lee, Ga-Won 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.2

In this paper, we compared and analyzed 3D silicon-oxide-nitride-oxide-silicon (SONOS) multi layer flash memory devices fabricated on nitride or oxide layer, respectively. The device fabricated on nitride layer has inferior electrical properties than that fabricated on oxide layer. However, the device on nitride layer has faster program / erase speed (P/E speed) than that on the oxide layer, although having inferior electrical performance. Afterwards, to find out the reason why the device on nitride has faster P/E speed, 1/f noise analysis of both devices is investigated. From gate bias dependance, both devices follow the mobility fluctuation model which results from the lattice scattering and defects in the channel layer. In addition, the device on nitride with better memory characteristics has higher normalized drain current noise power spectral density ($S_{ID}/I^2_D$>), which means that it has more traps and defects in the channel layer. The apparent hooge's noise parameter (${\alpha}_{app}$) to represent the grain boundary trap density and the height of grain boundary potential barrier is considered. The device on nitride has higher ${\alpha}_{app}$ values, which can be explained due to more grain boundary traps. Therefore, the reason why the devices on nitride and oxide have a different P/E speed can be explained due to the trapping/de-trapping of free carriers into more grain boundary trap sites in channel layer.