장단기 메모리를 이용한 노인 낙상감지시스템의 정규화에 대한 연구

정승수,김남호,유윤섭,Jeong, Seung Su,Kim, Namg Ho,Yu, Yun Seop 한국정보통신학회 2021 한국정보통신학회논문지 Vol.25 No.11

본 논문에서는 고령자의 낙상상황을 감지할 수 있는 텐서플로우 장단기 메모리 기반 낙상감지 시스템의 정규화에 대하여 소개한다. 낙상감지는 고령자의 몸에 부착한 3축 가속도 센서 데이터를 사용하며, 총 7가지의 행동 패턴들에 대하여 학습하며, 각각 4가지는 일상생활에서 일어나는 패턴이고, 나머지 3가지는 낙상에 대한 패턴이다. 학습시에는 손실함수(loss function)를 효과적으로 줄이기 위하여 정규화 과정을 진행하며, 정규화 과정은 데이터에 대하여 최대최소 정규화, 손실함수에 대하여 L2 정규화 과정을 진행한다. 3축 가속도 센서를 이용하여 구한 다양한 파라미터에 대하여 정규화 과정의 최적의 조건을 제시한다. 낙상 검출율면에서 SVM을 이용하고 정규화 127과 정규화율 λ 0.00015일 때 Sensitivity 98.4%, Specificity 94.8%, Accuracy 96.9%로 가장 좋은 모습을 보였다. In this paper, we introduce a regularization of long short-term memory (LSTM) based fall detection system using TensorFlow that can detect falls that can occur in the elderly. Fall detection uses data from a 3-axis acceleration sensor attached to the body of an elderly person and learns about a total of 7 behavior patterns, each of which is a pattern that occurs in daily life, and the remaining 3 are patterns for falls. During training, a normalization process is performed to effectively reduce the loss function, and the normalization performs a maximum-minimum normalization for data and a L2 regularization for the loss function. The optimal regularization conditions of LSTM using several falling parameters obtained from the 3-axis accelerometer is explained. When normalization and regularization rate λ for sum vector magnitude (SVM) are 127 and 0.00015, respectively, the best sensitivity, specificity, and accuracy are 98.4, 94.8, and 96.9%, respectively.

Transient Receptor Potential C4/5 Like Channel Is Involved in Stretch-Induced Spontaneous Uterine Contraction of Pregnant Rat

정승수,김영환,정지현,안덕선 대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.6

Spontaneous myometrial contraction (SMC) in pregnant uterus is greatly related with gestationalage and growing in frequency and amplitude toward the end of gestation to initiate labor. But, anaccurate mechanism has not been elucidated. In human and rat uterus, all TRPCs except TRPC2 areexpressed in pregnant myometrium and among them, TRPC4 are predominant throughout gestation,suggesting a possible role in regulation of SMC. Therefore, we investigated whether the TRP channelmay be involved SMC evoked by mechanical stretch in pregnant myometrial strips of rat usingisometric tension measurement and patch-clamp technique. In the present results, hypoosmotic cellswelling activated a potent outward rectifying current in G protein-dependent manner in rat pregnantmyocyte. The current was significantly potentiated by 1μM lanthanides (a potent TRPC4/5 stimulator)and suppressed by 10μM 2-APB (TRPC4-7 inhibitor). In addition, in isometric tension experiment,SMC which was evoked by passive stretch was greatly potentiated by lanthanide (1μM) andsuppressed by 2-APB (10μM), suggesting a possible involvement of TRPC4/5 channel in regulationof SMC in pregnant myometrium. These results provide a possible cellular mechanism for regulationof SMC during pregnancy and provide basic information for developing a new agent for treatmentof premature labor.

기억관련 신경약물학과 윤리적 문제

정승수 미래의료인문사회과학회 2019 FUTURE MEDICINE & HUMANITIES Vol.2 No.2

기억은 학습을 통해 얻어진 정보를 유지하는 것을 의미한다. 생물학적 관점에서 보면 기억은 뇌에서 신경 회로가 서로 연결된 것이라고 할 수 있다. 기억이 생성될 수 있는 것은 신경 세포 간의 접점인 시냅스의 전달 효율이 변하는 특성 즉, 시냅스 가소성이 있기 때문이다. 대뇌 피질의 네트워킹이 장기화 되고 반복됨에 따라 장기 기억으로 전환이 되는 과정을 기억의 응고라 하는데, 최근 연구에 따르면 장기 기억도 기억의 회상과 재응고 과정에서 새로운 자극을 가하면 기억이 둔화되거나 다른 기억으로 왜곡이 될 수 있다. 주로 외상후스트레스장애(PTSD)와 관련하여 기억의 이러한 특성을 이용한 치료 방법들이 많이 연구되고 있다. 그런데 약물을 이용하여 기억을 조절하는 것과 관련하여 우려되는 윤리적 문제들이 몇 가지 있다. 치료와 향상의 경계선에 있는 경우에는 환자의 최선의 이익이 무엇인지 그에 따른 위험과 비용을 보다 냉정하게 평가하여야 할 것이다. 또 이러한 기술의 사용으로 인한 혜택이 특정 계층에게 집중된다면 사회적 불평등을 심화시키는 원인이 될 수 있으며, 공정한 경쟁을 훼손시키는 수단으로 남용될 가능성도 있다. 그리고 약물을 통해 기억에 왜곡이 이루어진 경우 그 기억과 관련된 진술이나 증언의 법적 효력을 인정하기 어렵기 때문에 사회 전체의 신뢰와 형사 사법제도에 대한 규율의 측면도 새로운 고려가 필요하다. 마지막으로 무엇보다도 기억은 한 개인의 정체성을 구성하는 중요한 부분이라는 점에서 특별한 윤리적 고려가 필요하다. 기억 조절 약물의 사용은 개인에게 미칠 영향과 함께 인간성에 대한 전반적이고 종합적인 고려 하에서 이루어져야 할 것이다.  The memory means the retention of learned information. From a biological point of view, memory is a network of neural circuits in the brain. Memory can be created because of the synaptic plasticity, which is the changeable nature of the efficacy of synaptic transmission. Memory consolidation refers to the transformation into long-term memory as the cerebral cortical networking is prolonged and repeated. According to recent studies, long-term memory also can be dampened or altered by modifying the reconsolidation process. Treatment methods using this mechanism are mainly being studied for PTSD. However, there are some ethical issues in memory control through pharmaceuticals. If the patient is in the gray zone between treatment and enhancement, the best interest of the patient  should be assessed more strictly. Also, if memory control technology benefits only certain classes, it could be exploited as a means of deepening social inequality or bypassing fair competition. In addition, it affects the credibility of testimonies, so it is important to reconsider its impact on social trust and the criminal justice system. Finally, memory is a vital part of personal identity. Thus, we need to pay attention to the ethical issues in the use of memory control pharmaceuticals with a comprehensive consideration of its impact on individual lives and humanity. 

Lysophosphatidylcholine Increases Ca²+ Current via Activation of Protein Kinase C in Rabbit Portal Vein Smooth Muscle Cells

정승수,이영호,한성식,김영환,남택상,안덕선 대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.1

Lysophosphatidylcholine (LPC), a metabolite of membrane phospholipids by phospholipase A2, has been considered responsible for the development of abnormal vascular reactivity during atherosclerosis. Ca²+ influx was shown to be augmented in atherosclerotic artery which might be responsible for abnormal vascular reactivity. However, the mechanism underlying Ca²+ influx change in atherosclerotic artery remains undetermined. The purpose of the present study was to examine the effects of LPC on L-type Ca²+ current (ICa(L)) activity and to elucidate the mechanism of LPC-induced change of ICa(L) in rabbit portal vein smooth muscle cells using whole cell patch clamp. Extracellular application of LPC increased ICa(L) through whole test potentials, and this effect was readily reversed by washout. Steady state voltage dependency of activation or inactivation properties of ICa(L) was not significantly changed by LPC. Staurosporine (100 nM) or chelerythrine (3μM), which is a potent inhibitor of PKC, significantly decreased basal ICa(L), and LPC-induced increase of ICa(L) was significantly suppressed in the presence of PKC inhibitors. On the other hand, application of PMA, an activator of PKC, increased basal ICa(L) significantly, and LPC-induced enhancement of ICa(L) was abolished by pretreatment of the cells with PMA. These findings suggest that LPC increased ICa(L) in vascular smooth muscle cells by a pathway that involves PKC, and that LPC-induced increase of ICa(L) might be, at least in part, responsible for increased Ca²+ influx in atherosclerotic artery. Lysophosphatidylcholine (LPC), a metabolite of membrane phospholipids by phospholipase A2, has been considered responsible for the development of abnormal vascular reactivity during atherosclerosis. Ca²+ influx was shown to be augmented in atherosclerotic artery which might be responsible for abnormal vascular reactivity. However, the mechanism underlying Ca²+ influx change in atherosclerotic artery remains undetermined. The purpose of the present study was to examine the effects of LPC on L-type Ca²+ current (ICa(L)) activity and to elucidate the mechanism of LPC-induced change of ICa(L) in rabbit portal vein smooth muscle cells using whole cell patch clamp. Extracellular application of LPC increased ICa(L) through whole test potentials, and this effect was readily reversed by washout. Steady state voltage dependency of activation or inactivation properties of ICa(L) was not significantly changed by LPC. Staurosporine (100 nM) or chelerythrine (3μM), which is a potent inhibitor of PKC, significantly decreased basal ICa(L), and LPC-induced increase of ICa(L) was significantly suppressed in the presence of PKC inhibitors. On the other hand, application of PMA, an activator of PKC, increased basal ICa(L) significantly, and LPC-induced enhancement of ICa(L) was abolished by pretreatment of the cells with PMA. These findings suggest that LPC increased ICa(L) in vascular smooth muscle cells by a pathway that involves PKC, and that LPC-induced increase of ICa(L) might be, at least in part, responsible for increased Ca²+ influx in atherosclerotic artery.

논문발표 ( B . 목재구조·목질재료 ) : 혼합비에 따른 폐타이어와 목재 복합패널의 휨강도

정승수,황권환,이원희 한국목재공학회 1998 한국목재공학회 학술발표논문집 Vol.1998 No.-

3축 가속도 데이터를 이용한 장단기 메모리의 노드수에 따른 낙상감지 시스템 연구

정승수(Seung Su Jeong),김남호(Nam Ho Kim),유윤섭(Yun Seop Yu) 한국정보통신학회 2022 한국정보통신학회 종합학술대회 논문집 Vol.26 No.1

각 기종간 조종사에 대한 요통 유병률 비교

정승수 ( Seung-soo Chung ),최태성 ( Tae-sung Choi ),최재문 ( Jae-moon Choi ) 국군의무사령부 2004 대한군진의학학술지 Vol.35 No.1

대용량 연료전지용 수랭식 IGBT Stack 설계 및 성능 검증

정승수(Seung-soo Jeong),김병섭(Byung-seob Kim),손용훈(Yong-hoon Son),김재식(Jae-sig Kim),이진수(Jin-su Lee) 전력전자학회 2014 전력전자학술대회 논문집 Vol.2014 No.7

장단기 메모리 기반 노인 낙상감지에 대한 연구

정승수(Seung Su Jeong),유윤섭(Yun Seop Yu) 한국정보통신학회 2021 한국정보통신학회 종합학술대회 논문집 Vol.25 No.1

본 논문에서는 노령층 인구가 도보 시 일어날 수 있는 낙상상황을 텐서플로워를 이용하여 인지하기 위한 시스템에 대하여 소개한다. 낙상감지는 고령자의 몸에 착용한 가속센서 데이터에 대해서 텐서플로워를 이용하여 학습된 LSTM(long short-term memory)을 기반하여 낙상과 일상생활을 판별한다. 각각 7가지의 행동 패턴들에 대하여 학습을 실행하며, 4가지는 일상생활에서 일어나는 행동 패턴이고, 나머지 3가지는 낙상시의 패턴에 대하여 학습한다. 3축 가속도 센서의 가공하지 않은 데이터와 가공한 SVM(Sum Vector Magnitude)를 이용하여 LSTM에 적용해서 학습하였다. 이 두 가지 경우에 대해서 테스트한 결과 데이터를 혼합하여 학습하면 더 좋은 결과를 기대할 수 있을 것으로 예상된다. In this paper, we introduce the deep-learning system using Tensorflow for recognizing situations that can occur fall situations when the elderly are moving or standing. Fall detection uses the LSTM (long short-term memory) learned using Tensorflow to determine whether it is a fall or not by data measured from wearable accelerator sensor. Learning is carried out for each of the 7 behavioral patterns consisting of 4 types of activity of daily living (ADL) and 3 types of fall. The learning was conducted using the 3-axis acceleration sensor data. As a result of the test, it was found to be compliant except for the GDSVM(Gravity Differential SVM), and it is expected that better results can be expected if the data is mixed and learned.

열압밀화재를 위한 마이크로파의 효과

정승수(Sung Soo Jung),이원희(Weon Hee Lee) 한국가구학회 1998 한국가구학회지 Vol.9 No.2

This paper deals with an effect of microwave irradiation for compressed wood by a hot press of sonamu(Pinus densiflora) to improve the physical properties. Specimens lOOmm(L) by 20mm(R) by 20mm(T) of sap wood in air-dried and water-saturated conditions were used. Specimens were irradiated by microwaves of O.9kW(2450MHz) and hot-compressed to the radial direction. Moisture content remarkably decreased with the irradiation time of microwave increased. In the water saturated specimens, wood temperature steeply increased as the wood moisture decreased by microwave irradiation. From the consideration of compressive stress, wood can be regarded as a plastic material in a wet condition. This may be due mainly to the softening of the matrix components in the cell walls when heated in the water saturated conditions. Recovery of the set of compressed wood is considered to show the minimum value for the high temperature and high pressure above 1 atm in wood which is water saturation. Improvement in abrasion resistance and hardness were recognized in water saturated wood.<br/> These results show that microwave irradiation is suitable to plasticize of wood specimen impregnated with water, can be improve to physical properties of wood as the pretreatment for heat compression.<br/> Keyword: microwave irradiation, water saturated wood, compressed wood, physical property.<br/>