Analyses on the Performance of the CNN Reflecting the Cerebral Structure for Prediction of Cybersickness Occurrence

신정훈 한국융합신호처리학회 2019 융합신호처리학회 논문지 (JISPS) Vol.20 No.4

In this study, we compared and analyzed the performance of each Convolution Neural Network (CNN) by implementing the CNN that reflected the characteristics of the cerebral structure, in order to analyze the CNN that was used for the prediction of cybersickness, and provided the performance varying depending on characteristics of the brain. Dizziness has many causes, but the most severe symptoms are considered attributable to vestibular dysfunction associated with the brain. Brain waves serve as indicators showing the state of brain activities, and tend to exhibit differences depending on external stimulation and cerebral activities. Changes in brain waves being caused by external stimuli and cerebral activities have been proved by many studies and experiments, including the thesis of Martijn E. Wokke, Tony Ro, published in 2019. Based on such correlation, we analyzed brain wave data collected from dizziness-inducing environments and implemented the dizziness predictive artificial neural network reflecting characteristics of the cerebral structure. The results of this study are expected to provide a basis for achieving optimal performance of the CNN used in the prediction of dizziness, and for predicting and preventing the occurrence of dizziness under various virtual reality (VR) environments.

新羅 善德王代 皇龍寺 九層塔에 보이는 中華와 吳越

신정훈 대구가톨릭대학교 인문과학연구소 2021 인문과학연구 Vol.- No.44

King Taejong of the Tang Dynasty said to abolish King Seondeok of Silla. because King Seondeok was a woman. This is an official statement to the envoy of Silla. The envoys would have come to Silla and delivered the words of King Taejong of Tang. In the Samguksagi(三國史記), there is no discussion related to the words of King Taejong. However, in the records of the nine-story pagoda at Hwangnyongsa Temple in the Samgukyousa(三國遺事), it was said that if the nine-story pagoda was built at Hwangnyongsa Temple, Guhan(九韓) would come and pay tribute. In this way, if the king of Silla receives tribute from Guhan, it must be sacred. This sacredness of King Seondeok can be seen by the words of the the Bodhisattva of wisdom. Bodhisattva of wisdom said: The king of Silla is the royal family of India. The king of Silla was different from the barbarians in the east because of the Buddha's record. Bodhisattva of wisdom said that the king of Silla was sacred. In the end, King Taejong of the Tang Dynasty said there was a problem because King of Silla was a woman. This logic of King Taejong of the Tang Dynasty is refuted by the words of the Bodhisattva of wisdom. However, the phrase of the Hwangnyongsa Pagoda in Samgukyousa(三國遺事) is the same as the Guhan(九韓) cited in Dongdoseungribgi(東都成立記). The Guhan(九韓) cited in Dongdoseungribgi(東都成立記) are Japan, Zhonghua(中華), Owel(吳越) and others. Here, attention is paid to Zhonghua(中華) and Owel(吳越). Zhonghua refers to the Tang Dynasty of the reign of King Seondeok of Silla, and Owel refers to South China, which the Tang has as a territory. A spiritual person told Jajang(慈藏) that if Silla built a nine-story pagoda in Hwangryongsa Temple, Goohan would come and pay tribute. At the suggestion of Jajang, King Seondeok built a nine-story pagoda at Hwangnyongsa Temple. This was the will to receive tribute from the Tang, which is expressed in Junghoa(中華) and Oweal(吳越). The fact that Junghoa(中華) and Oweal(吳越) will pay tribute shows the independence of Silla. There is an event that caused this record to appear. It was the logic of Tang Taejong that a woman could not be a king.

高句麗 廣開土王代의 稗麗 征討와 後燕과의 冊封이 가진 의미

신정훈 중앙대학교 중앙사학연구소 2013 중앙사론 Vol.0 No.37

In 395 A.D., King Gwanggaeto of Goguryo conquered Paeryo in the area of Siramuren river. In that time, Later-Yan gone into war with Northern Wei. Northern Wei invaded territory of Later-Yan in march of 395 A.D. Northern Wei defeated utterly Later-Yan in Chamhabpa of Eastern Mongolia. In 385 A.D., Goguryo had a war with Later-Yan for taking Yodong.. After the war between Goguryo and Later-Yan, both countries became potential enemies for each other. Later-Yan had a battle with Northern Wei In 395 A.D. At that time, King Gwanggaeto conquered Paeryo without check of Later-Yan. Goguryo obtained flocks of sheep, horses and cattle. These material resources were used attack on Baekje. After conquest of Paeryo, King Gwanggaeto of Goguryo made a round of Yodong for hunting. In that time, Yodong was territory of Later-Yan. Later-Yan raise an large scale army against Northern Wei. In the face of these situations, the Goguryo forces could understand topograpies and planimetric feat1ures of Yodong area. Meanwhile, this theses takes note of relationship between Goguryo and Later-Yan. Goguryo employed a foreign policy in which it maintained the installation relationship with Later-Yan in 396 A.D.. At this time, Later-Yan was consistently attacked by Northern Wei. In this situation, if Goguryo had invaded in Later-Yan, Later-Yan had to raise the tomahawk with Goguryo and Northern Wei. On this reason, Later-Yan used installation relationship as a safety device. On one hand, Goguryo accepted installation relationship. Why did accept Goguryo installation relationship from Later-Yan? Because Goguryo was admitted the dominium in the region of Pyeongju, Yodong and Daebang by Later-Yan. Also, It had relevance to a relation with Baekje. Goguryo captured 58 castles and 700 country of Baekje in 396 A.D. In this situation, Goguryo could concentrated on attacking Baekje without unawaring of Later-Yan.

동해안 지역 재생에너지원 접속에 따른 과도안정도 여유 분석 및 발전제약 산정 연구

신정훈,정인주,오승찬,송지영,구현근,배문성,곽은섭,민재현 대한전기학회 2022 전기학회논문지 Vol.71 No.11

Increasing renewable energy resources can lead to critical stability problems in power systems. Specially in Korean power system, since the power generation complex is concentrated on the coast, there are constraints on transmitting to the load. If a connection of renewable energy resources near generator buses continues to grow, specially in the east cost, transient stability problems may arise due to shortage of transmission lines. Therefore, it is necessary to evaluate how much renewable energy access at each site can affect the power system by some stability index such as critical clearing time. This paper shows how to assess or calculate the margin of dynamic stability and verify the methodology through assessment of a practical power system. Based on the methodology, this paper analyzes the practical system and draws conclusions.

다이어그램 해석을 통한 회현동 낙후블록의 활성화 방안

신정훈,이진석,성기문 대한건축학회지회연합회 2013 대한건축학회지회연합회 학술발표대회논문집 Vol.2013 No.1

멀티센서와 딥러닝을 이용한 Al 6014, Al 6016 합금 레이저 겹치기 용접부 응고균열 예측

신정훈,강상훈,김철희,홍석준,강민정 대한용접·접합학회 2023 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2023 No.5

高麗 末期 倭寇의 침입과 기근에 따른 民生

신정훈 서울역사편찬원 2010 서울과 역사 Vol.- No.76

Koryeo had experience political cataclysm from King Choongjung to King Gongyang(1350~1392). Because in that period, Yuan Dynasty was moving away and new Dynasty Joseon was just before setting of the country. In that point, what condition of the livelihood in the end of the Koryeo?To this point, the population of the Koryeo need to be considered. Because when the livelihood had been stable, the population would have been increased. the population is the first element in deciding scale of the society. Songsa refered to the 2.1million in the population of the Koryeo. This document was the only population record about Koryeo. In this respect, Thomas Mckeown's assertion about the Great Britain is noticeable. The expansion of the population was found in England and Wales about 1800. He insisted that the increase of the population was due to increasing of nutrition. From this point, how was the population between 1350 and 1392 in the Koryeo? During the end of the Koryeo, Whegoo(倭寇; Japanese privates) invaded the territory of Koryeo for taking away rice and people. Whegoo's invasion brought the people a considerable damage in the Koryeo. First of all, the people couldn’t help leaving their own place and made the people suffer a severe famine. Clearly, the land for agriculture was devastated. And The long spell of dry weather and famine had continued from 1351 to 1392. Also the government organization, Uichang was disappeared. Uichang was in charge of relief work. Moreover, Whegoo’s frequent invasions made people unable to produce any more marine products and salt. Marine products were main lifeline in the days. Salt was indispensible in the digestion of food as well. The livelihoods of the public in the end of the Koryeo had been collapsed. On the whole, the people during the end of the Koryeo was deficient situation of nutrition. The reduction of nutrition was the main factor in diminution of the people. The Population decline in the Koryeo caused the reduction in the government revenue. In the light of these facts, Koryeo Dynasty suffered a political disturbance between 1350~1392. 고려가 쇠퇴해가는 1350년 무렵부터 멸망한 시기인 1392년까지 인구의 동향은 영양섭취와 밀접한 관계가 있었다. 이 기간 동안 고려 사람들은 심각한 영양결핍 상태에 놓여 있었다. 왜구가 1350년부터 끈질기게 침입해왔다. 왜구는 세곡을 운반하는 조운선을 약탈했으며, 수도인 개경 인근에 지속적으로 침입하였다. 특히 공민왕 22년에 왜구는 대규모로 침입해왔다. 왜적은 漢陽府(서울)에 들어와 민가를 태우고 백성을 약탈하여 수 백리가 소란해졌다. 이 영향으로 수도인 개경이 크게 혼란스러웠다. 공민왕의 뒤를 이은 우왕대에는 왜구가 초기의 연해지방에서 나아가, 내륙 깊숙이까지 침입하였다. 그리하여 바닷가로부터 30∼50리 떨어진 지대에서야 사람들이 거주하게 되었다. 자연히 바다 가까운 곳에 있는 비옥한 토지에서 농사를 지을 수 없게 되었다. 또한 고려시대의 수재와 한재 빈도는 1351년∼1392년 무렵이 다른 시기에 비해 월등히 높다. 특히 기근은 이 시기에 무려 23회가 집중되어 있다. 수재와 한재는 농업생산량을 감소시키며 기근은 사망률을 높인다. 이러한 상황은 이 시기 고려인들의 영양 상태를 악화시켰다. 국가의 구휼기관인 義倉도 소멸되었다. 이와 함께 이 시기에는 왜구의 침략으로 어업활동을 제대로 할 수 없게 되었다. 고려인들의 주요한 단백질 섭취원은 생선과 해산물이었다. 어획량의 격감에 따라 고려 말에 사람들은 단백질의 원천을 제대로 섭취하지 못했다. 소금 역시 왜구의 침략과 소금을 생산하는 鹽戶의 도산, 권세가들의 염분 탈점으로 공급이 부족하게 되었다. 소금은 인간에게 꼭 필요한 나트륨과 염소를 공급하는 음식물이다. 소금부족으로 이 시기 사람들의 건강은 위협받고 있었다. 고려 말기에 왜구의 침입과 가뭄과 기근의 지속이 동시에 이루어진 것은 사람들의 영양 상태를 악화시켰다. 여기에다 어업의 붕괴와 소금섭취의 부족, 義倉의 소멸은 고려인들을 영양결핍상태로 이끌었다. 이 시기에 민생은 파탄되고 있었다. 이러한 요인들이 고려 말기의 정치적 동요에 영향을 끼쳤다고 보여 진다.

전기자동차 파우치형 배터리 열관리 시스템의 냉각성능 향상에 대한 연구

신정훈,이준경,Shin, Jeong-Hoon,Lee, Jun-Kyoung 한국산업융합학회 2022 한국산업융합학회 논문집 Vol.25 No.5

In many electric vehicles, large-capacity pouch-type lithium-ion battery packs are mainly used to increase the mileage on a single charge. The lithium ion battery should be operated within the temperature range of 25℃ to 40℃ because the battery performance can be rapidly deteriorated due to an increase in internal temperature. Battery thermal management system (BTMS) can give the suitable temperature conditions to battery by water cooling method. In this research, the heat transfer characteristics (the battery temperature distributions and the water flow characteristics) were analyzed by CFD method to investigate the thermal performance of the cooling plate with 4-pass water flow structure. Moreover, the effect of the presence of fins between the battery cell was identified. The fins made smooth temperature distributions between the battery cells due to the heat spreading and lower the average battery cells temperature.

[서평] 김영나, 『1945년 이후 한국 현대미술』

신정훈 미술사연구회 2020 미술사연구 Vol.- No.38

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Comparative study on reduced models of unsteady aerodynamics using proper orthogonal decomposition and deep neural network

신정훈,Kum Won Cho 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

Data-driven researches based on various machine learning techniques, are being actively explored in science and technology areas. In the area of computational fluid dynamics, several studies have already been conducted in a reduced order modeling technique using principal orthogonal basis called proper orthogonal decomposition (POD). Recently the application of machine learning techniques represented by deep learning or deep neural network (DNN) to the existing reduced order model methods is increasingly drawing attention with the development of processor hardware technology such as GPU. This study, based on the data produced by a state-of-the-art flow solver, examined both POD and DNN techniques to three different methods: a) classical non-intrusive POD with local linear regression, b) fully-connected DNN, and c) mixed POD-DNN. Method a) and c) have difference in computing superposed time expansion coefficients. The target problem is unsteady aerodynamic simulation of a two dimensional airfoil with fixed angle-of-attack and three grid and flow condition sets: (structured grid, inviscid flow, Mach 0.2), (structured grid, turbulent flow, Mach 0.6, Reynolds 1x10 5 ), and (unstructured grid, laminar flow, Mach 0.4). The comparison items were flow fields of velocity/pressure for all cases and aerodynamic lift/drag performances only for the structured grid system respectively. In these computations the overall tendencies of aerodynamic lift and drag are similar, but the POD with existing local linear regression method in calculating time coefficients was found to show the highly robust and moderately accurate predictions. The direct DNN method was judged to be able to be used as a feasible reduced order model since it overcomes linearity error at both extracting POD basis and determining coefficients and has an advantage to be able to infer flow variables in arbitrary spatial locations. It showed better level of error than the classical POD method, but had model optimization cost to tune hyper-parameters and determine how many training data should be obtained to mitigate partial error. As an intermediate way, the mixed POD-DNN provided a robust reduced model of airfoil aerodynamic simulation due to the moderate computational cost and better accuracy comparing to the two other methods, but it had a shortcoming of fixed spatial coordinates like the classical POD method because the POD basis has fixed dimension of vector. In conclusion, fully-connected deep neural network method is helpful to predict flow field distribution as a universal field approximator in accordance with time and space such as fluid field simulation in this study, and, what is better, using POD basis will augment the accuracy and computational efficiency.