Development of Upper Limb Training and Assessment Systems for Stroke Patient Rehabilitation using a Driving Simulator

Hosang Oh,Hwa-Kyung Shin,Myoungouk Park,Han-Seoung Choe,Jeon-Il Moon,Joonwoo Son 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.11

Objective: The aim of this study is to develop the upper limb training and assessment systems for stroke patient rehabilitation using a driving simulator. Background: About 795,000 people experience a new or recurrent stroke in the United States each year, and lots of researchers are suggesting effective rehabilitation methods. In most of their studies, however, pre- and post-assessments tool using some clinical scales were used for the assessment tool of the recovery through upper limb rehabilitation. In some studies, physiological measure was considered as important factor for rehabilitation process from earlier studies. Method: The experiment for the assessment is conducted at a fixed-based driving simulator. The proposed rehabilitation assessment system consists of quantitative assessment using driving simulator, motion analysis system, EMG (Electromyograph), ECG (Electrocardiograph), EEG (Electroencephalograph), gaze tracker, body pressure sensor and myotonometer and subjective assessment using clinical scale such as CNT (Computerized Neurocognitive Function Test) and UFOV(Useful Field of View). In order to quantitatively compare the upper limb function during assessment, the driving performance measures (speed, steering activity, and etc.), upper limb function (muscle activity, kinematics and etc.) and physiological measures (EEG, ECG and etc.) were collected from each subsystem. Results: This driving simulator based rehabilitation system can be utilized as training method for stroke patient, because the training using the steering activity can affect skeletomuscular system positively. The proposed system can offer objective method for assessing a training effect by using driving performance, upper limb function and physiological measures. In addition, the system can measure the driving performance that can be used for evaluating the driving ability of stroke drivers. Conclusion: The proposed upper limb rehabilitation system can be used as a combined system for quantitative and subjective assessment through driving simulator.

운전수행도와 생리학적 신호를 이용한 신경망 기반 인지부하의 감지

오호상(Hosang Oh),손준우(Joonwoo Son) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

The paper suggests an algorithm for detecting driver’s high cognitive workload using driving performance and physiological data. The algorithm adopts radial basis probabilistic neural network (RBPNN) to construct estimation models. In order to train and test the models, combinations of two driving performance data including velocity and steering wheel reversal rate(SRR), and three physiological signals including inter-beat interval(IBI), skin conductance level(SCL) and skin temperature were considered as measures of cognitive workload. The training and testing data were collected from on-road driving experiments of 13 subjects who were asked to complete three levels of difficulty of a delayed digit-recall task (n-back task). As a result, The best performance was achieved from a combination of measures including SCL, skin temperature and velocity over 10 seconds time window with an average accuracy of 94.2%. It is expected that the accuracy can be improved applying more sophisticated algorithms and various window sizes and combinations.

Centimeter-sized epitaxial h-BN films

Oh, Hongseok,Jo, Janghyun,Tchoe, Youngbin,Yoon, Hosang,Hwi Lee, Hyun,Kim, Sung-Soo,Kim, Miyoung,Sohn, Byeong-Hyeok,Yi, Gyu-Chul Springer Science and Business Media LLC 2016 NPG Asia Materials Vol.8 No.-

MR 댐퍼를 이용한 대형 버스 현가장치의 반능동 제어

윤호상(Hosang Yoon),문일동(Ildong Moon),김재원(Jaewon Kim),오재윤(Chaeyoun Oh),이형원(Hyungwon Lee) 한국생산제조학회 2012 한국생산제조학회지 Vol.21 No.4

In this work, the semi-active control of a large-sized bus suspension system with an MR damper was studied. An MR damper model that can aptly describe the hysteretic characteristics of an MR damper was adopted. Parameter values of the MR damper model were suitably modified by considering the maximum damping force of a passive damper used in the suspension system of a real large-sized bus. In addition, a fuzzy logic controller was developed for semi-active control of a suspension system with an MR damper. The vertical acceleration at the attachment point of the MR damper and the relative velocity between sprung and unsprung masses were used as input variables, while voltage was used as the output variable. Straight-ahead driving simulations were performed on a road with a random road profile and on a flat road with a bump. In straight-ahead driving simulations, the vertical acceleration and pitch angle were measured to compare the riding performance of a suspension system with a passive damper with that of a suspension with an MR damper. In addition, a single lane change simulation was performed. In the simulation, the lateral acceleration and roll angle were measured in order to compare the handling performance of a suspension system using a passive damper with that of a suspension system using an MR damper.

Thermal Behavior of Solid Electrolyte Interphase Films Deposited on Graphite Electrodes with Different States-of-Charge

Park, Hosang,Yoon, Taeho,Kim, Youngjin,Lee, Jae Gil,Kim, Jongjung,Kim, Hyun-seung,Ryu, Ji Heon,Kim, Jae Jeong,Oh, Seung M. The Electrochemical Society 2015 Journal of the Electrochemical Society Vol.162 No.6

<P>The thermal degradation of surface films (solid electrolyte interphase, SEI) and their repairing behaviors are examined on graphite electrodes that have different states-of-charge (SOC). In detail, a fully passivating SEI layer is generated in advance and then stored at 85°C for a prolonged time. The surface films (SEI) are thermally degraded upon high-temperature exposure. The damaged films are repaired by electrolyte decomposition and concomitant film deposition, during which Li<SUP>+</SUP> ions/electrons are supplied from the graphite electrodes, which appears as an increase in the open-circuit voltage (OCV) of the graphite electrodes. The repaired surface films show a comparable passivating ability along with a similar morphology and chemical composition to that of the initial SEI layers. The degradation/repairing continues until the graphite electrodes are fully de-lithiated (OCV = 3.0 V vs. Li/Li<SUP>+</SUP>). Once the graphite electrodes are fully de-lithiated, the damaged surface films cannot be repaired because the Li<SUP>+</SUP> ions/electrons are exhausted in the graphite electrodes. Because of the incomplete repairing, the graphite surface becomes poorly covered by surface films, which leads to a loss of passivating ability.</P>

Nearly single crystal, few-layered hexagonal boron nitride films with centimeter size using reusable Ni(111)

Hongseok Oh,Janghyun Jo,Hosang Yoon,Youngbin Tchoe,Sung-Soo Kim,Miyoung Kim,Byeong-Hyeok Sohn,Gyu-Chul Yi 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.2

인터넷 면세점에서 연관규칙기법을 이용한 고객 프로파일 기반의 상품 추천에 관한 연구

오승식 ( Seungsik Oh ),정호상 ( Hosang Jung ),이제용 ( Jeyong Lee ) 한국로지스틱스학회 2019 로지스틱스연구 Vol.27 No.2

해외 여행객의 증가에 따라 대표적인 관광 관련 산업 중 하나인 면세점 시장은 고속 성장하고 있다. 특히 인터넷 면세점은 시공간의 제약 없이 손쉽게 이용 가능하다는 점에서 오프라인 면세점과 비교하여 더욱 빠르게 성장하고 있다. 인터넷 면세점의 급성장 요인은 뛰어난 가격 경쟁력과 오프라인에서는 갖출 수 없는 상품구색을 꼽을 수 있다. 하지만, 상품 종류가 수만 개로 많고, 여행 목적지가 매우 다양하기에 고객의 취향에 맞춰 적절한 상품을 추천하는 것이 인터넷 면세점 입장에서는 중요한 과제로 떠오르고 있다. 본 연구에서는 대표적인 추천기법의 하나인 연관규칙기법을 이용하여, 상품 추천 규칙을 도출하고 도출된 규칙을 성별, 연령, 국적, 여행 목적지 정보 등의 고객 관련 정보를 활용하여 분석하였다. 특히 인터넷 면세점 A사의 과거 6개월간의 실제 판매데이터를 활용하여 연구를 진행하였고, 분석 결과를 토대로 유의미한 상품 간 연관규칙 및 이를 활용할 수 있는 방안을 도출하였다. 분석 결과는 A사의 실무 담당자로부터 의미 있는 결과라는 평가를 받았으며, 본 연구에서 제안하는 인터넷 면세점을 위한 추천시스템 개발 및 결과 분석방안은 향후 국내외 인터넷 면세점들의 관련 시스템 도입 검토 등에 도움이 될 것으로 기대된다. In recent years, the duty-free industry is growing at a rapid pace with the popularization of international traveling. Especially, online duty-free stores are growing fast because there are no restrictions on time and space in comparison with offline duty-free stores. Also, they have a competitive price and a lots of various items. However, too many goods on the online duty-free stores have trouble in connecting customer needs to purchase. In this paper, we analyzed performance of recommendation system by using association rules analysis. For analysis, we focused on online duty free shopping customers, and generated the association rules analysis result which can be used for the item recommendation system. The analysis of this paper was also validated by the practitioners working for one of the Korean duty free stores, and was well received. The research results will be helpful for the online duty free stores that consider developing recommendation system to strengthen competitiveness.

새만금 외측 조간대의 저서미세조류 일차 생산성 변동

권봉오(Bong-Oh Kwon),김호상(Hosang Kim),권인하(Inha Kwon),윤서준(Seo Joon Yoon),이인옥(In Ok Lee),김종성(Jong Seong Khim) 한국해양환경·에너지학회 2022 한국해양환경·에너지학회 학술대회논문집 Vol.2022 No.6

PEEC 방법을 이용한 다이폴 안테나와 전송선로 사이의 전자기 결합 분석에 관한 연구

오정준(Jeongjoon Oh),김광호(Kwangho Kim),박명구(Myeongkoo Park),이호상(Hosang Lee),나완수(Wansoo Nah) 한국전자파학회 2017 한국전자파학회논문지 Vol.28 No.11

최근 모바일 기기는 다기능, 고성능화로 정보 처리 속도는 빠르게 증가하고, 제품의 크기는 소형화, 집적화되면서 기기 내부의 회로는 안테나 또는 인접 회로로부터 방사되는 전자기 간섭에 쉽게 노출되게 되었고, 제품의 성능 저하 및 오동작을 유발시킨다. 이를 방지하기 위해 제품의 설계 단계에서 EM 시뮬레이션을 통해 제품의 전자기적 특성을 예측하고, 이를 고려하여 설계해야 하지만, EM 시뮬레이터는 분석 시간이 오래 걸리고, 분석시간을 단축시키기 위해서 고사양의 시스템 자원이 필요하다. 본 논문에서는 PEEC 방법을 이용하여 원형 전선에 대한 전자기적 특성을 빠르게 분석하는 방법을 제시하였다. PEEC 방법은 도체 내부의 전계 적분 방정식으로부터 도체의 등가회로를 모델링하고, 회로 분석법을 통해 전자기적 특성을 분석할 수 있는 방법으로, EM 시뮬레이터 대비 빠른 시간 안에 전자기적 특성을 분석할 수 있다. 본 논문에서 제시한 방법을 통해 다이폴 안테나로부터 전송선로로의 전자기 결합을 주파수 영역에서 분석하였고, 이를 EM 시뮬레이터의 분석 결과와 비교해 PEEC 방법의 유효함을 검증하였다. In recent years, mobile devices have become increasingly multi-functional and high performance, resulting in a dramatical increase in processing speed. On the other hand, the size of device is reduced, circuits inside the device are more easily exposed to electromagnetic interference radiated from antenna or adjacent circuits, degrading the system performance. To prevent this, it is necessary to design the device considering the electromagnetic characteristics with EM simulation at the design stage of product. However, the EM simulation takes a long analysis time and require high-level system resources for fast analysis. In this paper, an equivalent circuit modeling method for a round wire is proposed using a PEEC method and the electromagnetic coupling from a dipole antenna to a transmission line is analyzed in frequency domain. And compared with the result of electromagnetic simulator. As a result, PEEC method shows good agreement with those of electromagnetic simulation, in a much more short time.

Identification of Driver Cognitive Workload Using Support Vector Machines with Driving Performance, Physiology and Eye Movement in a Driving Simulator

Son, Joonwoo,Oh, Hosang,Park, Myoungouk Korean Society for Precision Engineering 2013 International Journal of Precision Engineering and Vol.14 No.8

This paper suggests experimental approaches for identifying driver's cognitive workload using support vector machines (SVMs) with driving performance, physiological response and eye movement data. In order to construct a classification model for detecting high cognitive workload condition, driving simulation experiments were conducted. For the experiments, 30 participants (15 younger males in the 25-35 age range (M = 27.9, SD = 3.13) and 15 older males in the 60-69 (M = 63.2, SD = 1.74)) drove a simulated highway in a fixed-base driving simulator. While driving through 37 km of straight highway, participants conducted three levels of cognitive secondary tasks, i.e. an auditory delayed digit recall task, at specified segments for 10 minutes and their driving performance, physiological response and eye movement data were collected. In this study, the model performances with different combination of measures were assessed with the nested cross-validation method. As a result, it was demonstrated that the proposed SVM models were able to identify driver's cognitive workload with high accuracy. The best performance was achieved with a combination of the standard deviation of lane position (SDLP), physiology and gaze information. The best model obtained 89.0% accuracy, sensitivity of 86.4% and specificity of 91.7%.