근전도 트리거 손목 재활 훈련 시스템 개발

김영훈,리두이콴,지영준,안경관,황창호,Kim, Younghoon,Le, DuyKhoa,Chee, Youngjoon,Ahn, Kyoungkwan,Hwang, Changho 대한의용생체공학회 2013 의공학회지 Vol.34 No.3

This study is about the development of the wrist rehabilitation system for the patient who has limited capability of movement after stroke. Electromyography triggered training system (ETTS) can play the role between complete passive training and patient activating training system. Surface EMG was measured on pronator teres muscle and biceps brachii muscle for wrist pronation and supination. Our system detects whether the subject makes muscular effort for pronation or supination or nothing in every 50 ms. When the effort level exceeds the preset percentage of maximal voluntary contraction, the motor rotates according to the direction of the intention of the subject. EMG triggers the motor rotation for the wrist rehabilitation training until the preset angle. To evaluate its performance, the maximum voluntary contraction level was measured for 4 subjects at first. With the audio-visual instruction to rotate the wrist (pronation or supination) the subjects made effort to follow the instruction. After calculating root mean square (RMS) for 50 ms, the controller determines whether there was muscular effort to rotate while holding the motor. When there was an effort to rotate, the controller rotates the motor 0.8 degree. By comparing the RMS values from two channels of EMG, the controller determines the rotational direction. The onset delay is $0.76{\pm}0.24$ s and offset delay is $0.65{\pm}0.22$ s for pronation. For supination the onset delay is $1.24{\pm}0.41$ s and offset delay is $0.77{\pm}0.22$ s. The system responded fast enough to be used for rehabilitation training. The controller perceived the direction of rotation 100% correctly for the pronation and 97.5% correctly for supination. ETTS was developed and the fundamental functions were validated for normal subjects. The clinical validation should be done with patients for real world application. With ETTS, the subjects can train voluntarily over the limitation of the range of motion which increases the effectiveness of the rehabilitation training.

우유 유래 고령친화 및 뇌질환 예방 식품소재 및 제품개발

김영훈,오남수,Kim, Younghoon,Oh, Nam Su 한국축산식품학회 2016 축산식품과학과 산업 Vol.5 No.1

전산유동해석에 의한 발사체 공력 특성 예측에 관한 연구

김영훈(Younghoon Kim),옥호남(Honam Ok),김인선(Insun Kim) 한국전산유체공학회 2004 한국전산유체공학회 학술대회논문집 Vol.2004 No.-

A space launch vehicle departs the ground in a low speed, soon reaches a transonic and a supersonic speed, and then flies in a hypersonic speed into the space. Therefore, the design of a launch vehicle should include the prediction of aerodynamic characteristics for all speed regimes, ranging from subsonic to hypersonic speed. Generally, Empirical and analytical methods and wind tunnel tests are used for the prediction of aerodynamic characteristics. This research presents considerable factors for aerodynamic analysis of a launch vehicle using CFD. This investigation was conducted to determine effects of wake over the base section on the aerodynamic characteristics of a launch vehicle and also performed to determine effects of the sting which exist to support wind tunnel test model.

한국 대학에서 영문학교육의 해체와 그 해체의 (불)가능성

김영훈(Younghoon Kim) 한국영미문학교육학회 2014 영미문학교육 Vol.18 No.1

The commercialization of higher education no longer surprises anyone. Contemporary capitalistic cultures and forces have transformed almost every aspect of Korean universities. This change radically dismantles the traditional authority and character of the humanities, once claimed as the sanctum of knowledge and the spirit of the modern university. While examining the capitalistic transformation of Korean universities, this article reviews what English studies in Korea faces as challenges. Over the course of the last twenty years many English departments in Korean universities drastically rebuilt their course curricula in order to strengthen practical English education. This curriculum reform was a convenient and arguably the most effective way of justifying the social functions and purposes of English studies in Korea. The consecutive deterioration of literary education in English studies, however, also raised concerns and disputes regarding the academic integrity and identity of English studies, while echoing with various discourses on the decline of the humanities in general. Then, what is the origin of the decline of the humanities or of the English department in Korea? And what can be a performative and rightful response to this crisis or change in English studies? What is the (im)possiblity of literary studies or literature in a society where the humanities simply fail to matter? This article attempts to answer these questions. After examining the contemporary challenges of English studies in Korea in a historical context, this essay introduces Jacques Derrida’s idea of the university to come. In doing so, it reformulates today’s challenges as a condition for constituting the university without condition, in which literary education re-defines and re-invents its meaning and existence.

강유전체 캐패시터를 이용한 뉴런 시그널 감지 및 무집, 무전원 측정 시스템 개발

김영훈(Younghoon Kim),Petronil Noubeth,이기근(Keekeun Lee) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.10

Conflict Graphical Model of Feature Selection

Younghoon Kim(김영훈),Sangho Shim,Seoung Bum Kim(김성범) 대한산업공학회 2015 대한산업공학회 춘계학술대회논문집 Vol.2015 No.4

XGBoost를 활용한 리스크패리티 자산배분 모형에 관한 연구

김영훈(Younghoon Kim),최흥식(HeungSik Choi),김선웅(SunWoong Kim) 한국지능정보시스템학회 2020 지능정보연구 Vol.26 No.1

Artificial intelligences are changing world. Financial market is also not an exception. Robo-Advisor is actively being developed, making up the weakness of traditional asset allocation methods and replacing the parts that are difficult for the traditional methods. It makes automated investment decisions with artificial intelligence algorithms and is used with various asset allocation models such as mean-variance model, Black-Litterman model and risk parity model. Risk parity model is a typical risk-based asset allocation model which is focused on the volatility of assets. It avoids investment risk structurally. So it has stability in the management of large size fund and it has been widely used in financial field. XGBoost model is a parallel tree-boosting method. It is an optimized gradient boosting model designed to be highly efficient and flexible. It not only makes billions of examples in limited memory environments but is also very fast to learn compared to traditional boosting methods. It is frequently used in various fields of data analysis and has a lot of advantages. So in this study, we propose a new asset allocation model that combines risk parity model and XGBoost machine learning model. This model uses XGBoost to predict the risk of assets and applies the predictive risk to the process of covariance estimation. There are estimated errors between the estimation period and the actual investment period because the optimized asset allocation model estimates the proportion of investments based on historical data. these estimated errors adversely affect the optimized portfolio performance. This study aims to improve the stability and portfolio performance of the model by predicting the volatility of the next investment period and reducing estimated errors of optimized asset allocation model. As a result, it narrows the gap between theory and practice and proposes a more advanced asset allocation model. In this study, we used the Korean stock market price data for a total of 17 years from 2003 to 2019 for the empirical test of the suggested model. The data sets are specifically composed of energy, finance, IT, industrial, material, telecommunication, utility, consumer, health care and staple sectors. We accumulated the value of prediction using moving-window method by 1,000 in-sample and 20 out-of-sample, so we produced a total of 154 rebalancing back-testing results. We analyzed portfolio performance in terms of cumulative rate of return and got a lot of sample data because of long period results. Comparing with traditional risk parity model, this experiment recorded improvements in both cumulative yield and reduction of estimated errors. The total cumulative return is 45.748%, about 5% higher than that of risk parity model and also the estimated errors are reduced in 9 out of 10 industry sectors. The reduction of estimated errors increases stability of the model and makes it easy to apply in practical investment. The results of the experiment showed improvement of portfolio performance by reducing the estimated errors of the optimized asset allocation model. Many financial models and asset allocation models are limited in practical investment because of the most fundamental question of whether the past characteristics of assets will continue into the future in the changing financial market. However, this study not only takes advantage of traditional asset allocation models, but also supplements the limitations of traditional methods and increases stability by predicting the risks of assets with the latest algorithm. There are various studies on parametric estimation methods to reduce the estimated errors in the portfolio optimization. We also suggested a new method to reduce estimated errors in optimized asset allocation model using machine learning. So this study is meaningful in that it proposes an advanced artificial intelligence asset allocation model for the fast-developing financial markets.

북한의 농림축산물 교역 동향 분석과 향후 전망

김영훈(Kim Younghoon),전형진(Chon Hyoungjin),임채환(Lim Chehwan) 한국농촌경제연구원 2019 한국농촌경제연구원 기본연구보고서 Vol.- No.-

Background and Purpose of Research Recently the situation on the Korean peninsula has suddenly changed in a positive direction. If South and North Korea and the US agree on denuclearization and a peace regime in the current ongoing dialogue, it will be a breakthrough in inter-Korean relations, and economic exchange between the two Koreas which ceased can begin again. This study was carried out as part of the groundwork in preparation for resuming inter-Korean trade in agricultural, forest and livestock products. The purpose of this study is to analyze the current state of and changes in North Korea"s trade in agricultural, forest and livestock products, and seek ways to promote inter-Korean trade in these products based on the analysis when economic exchange between the two Koreas is resumed. Method of Research Statistics on North Korea"s international trade have not been announced. In this situation, the statistics can be constructed only by utilizing trade statistics of the country"s all trade partners. This study constructed statistics on North Korea"s international trade in agricultural, forest and livestock products as mirror statistics by using UN Comtrade statistics. Research Results and Implications North Korea"s trade in agricultural, forest and livestock products has maintained the trade structure of a less developed country for a long time. The country"s major exports consist of collected forest products and agricultural and animal by-products. Among North Korea"s imports, grains including food and soybeans account for the largest share. Also, the country"s trade size is so small that increases or decreases in trade in a few particular commodities affect the total trade size. If the current ongoing dialogue among South and North Korea and the US progresses, conditions that can promote North Korea"s international trade again may be created with the lifting of sanctions. However, as a change of North Korea"s socialist economic system cannot be expected in the short term, it is difficult to forecast that only easing sanctions will greatly increase the country"s trade in agricultural, forest and livestock products and soon improve the trade structure. The key to promoting inter-Korean agricultural cooperation and developing North Korea"s agriculture is to boost commercial trade. Therefore, it is necessary to first implement leading development cooperation projects in the agriculture sector; enhance the production capacity of North Korean agriculture by using the projects as incubators; and improve the country"s trade structure of agricultural, forest and livestock products and increase trade. On the other hand, in the leading agricultural cooperation projects, the selection of crops for inter-Korean trade is important. If importing agricultural and livestock products from North Korea can contract domestic agriculture, it is difficult to promote inter-Korean trade in the products. Thus, at the early stage of agricultural cooperation, it is desirable for North Korea to produce agricultural and livestock products which South Korea has already steadily imported.

Constructing Area Cartogram Using a GIS Based Circular Cartogram Technique

YoungHoon Kim(김영훈) 대한지리학회 2008 대한지리학회지 Vol.43 No.2

지리정보시스템(Geographic Information System, GIS) 활용이 확대됨에 따라서 다양하고 복잡한 사회경제적 변수의 시각적 전달은 공간 분석과 더불어 중요한 연구 주제라고 할 수 있다. 그러나 시각화 기술 자체의 복잡성과 GIS와의 연계성 부족으로 인해 지도화 및 시각화 기법이 제공하는 여러 장점들이 제대로 전달되고 있지 못하고 있다. 이에 대하여 본 연구에서는 카토그램(cartogram) 기법을 적용하여 다양한 인구 관련 변수의 공간적 관계를 효과적으로 지도화할 수 있는 방법을 논의하고자 한다. 이를 위하여 본 연구에서는 범용 GIS 프로그램에서 카토그램이 쉽게 제작될 수 있는 환경을 제안하고, 일반인이나 GIS 초급자들도 손쉽게 구현할 수 있는 과정을 제시하였다. 또한 카토그램의 시각적 정보 전달 및 활용성 증대을 위해서 본 연구에서는 Dorling (1996)이 개발한 원형 카토그램 알고리즘(Circular Cartogram Algorithm, CCA)과 ArcView GIS 3.3. 프로그램의 내적 결합 방법을 적용하여 CCA 기반의 원형 카토그램이 범용 GIS 프로그램내에서 효과적으로 구현될 수 있는 사례를 제시하였다. 마지막으로 실질적인 카토그램 제작 사례로써 2005년 인구 센서스 자료를 대상으로 인구와 가구 변수의 카토그램 지도를 통한 관련 센서스 변수들과 지리적인 공간 분포 패턴의 시각적 분석의 가능성을 제안하였다. Many cartographers have for many years searched for a way to construct cartograms in which the sizes of geographic areas such as states, counties or census tracts are rescaled in proportion to their population or some other socio-economic properties. While many techniques and algorithms for creating cartograms have been proposed, some of them are still extremely complex to generate in a proper manner, and many of them suffer either from this lack of readability or from seamless integration with GIS software. This paper, therefore, presents a simple population cartogram technique based on the Circular Cartogram Algorithm(CCA) by Dorling(1996) to tackle these drawbacks by drawing the areas as simple circles for use as a base map and linking the construction with GIS mapping processes. For an automated approach in the cartogram generation, this paper proposes a close coupling method of ArcView GIS 3.3. package in order for users to access to the cartogram algorithm. Then, they will be available through an interface that the ArcView GIS system allows user-written routines to be accessed easily. The CCA and its coupling architecture ensure to improve the potential applicability of the use of cartograms to census mapping at practical levels. As the cartogram examples, cartograms of population and property types in 2005 Korea census data sets are illustrated in the end, by which viewers can easily identify the residential concentration and their relative ratio in Seoul metropolitan area.

Graph-free Label Propagation with Collaborative Dual Evolving Network for Big Data

Younghoon Kim(김영훈),Seoung Bum Kim(김성범) 대한산업공학회 2018 대한산업공학회 추계학술대회논문집 Vol.2018 No.11