가상 소방 훈련에서 컨트롤러 양식에 따른 사용자 요인 조사

전승곤,백승원,양웅연,한경식 한국차세대컴퓨팅학회 2020 한국차세대컴퓨팅학회 논문지 Vol.16 No.5

A virtual reality (VR) controller plays a key role in supporting interactions between users and the virtual environment, and many VR systems have developed tools that are identical to actual equipment. While the use of real tools can provide a more realistic experience, it can also have negative effects, such as an increased cognitive burden on users. We studied such an aspect through the lenses of three human factor constructs - perceived presence, learning experience, and cognitive load. We developed a VR firefighting training system integrated with essential firefighting tools, which were physically identical to the real ones. We conducted two user studies to compare the user experience for the VR system with the standard VR controllers, the one with the real tools, and a hybrid system. As a result, the hybrid condition showed similar levels of perceived presence and learning experiences than the real tool condition and a similar level of cognitive load as the standard controller condition. This shows that having a larger number of real devices does not necessarily guarantee a higher level of user experience and suggests a strategic approach to the development and utilization of control devices in VR systems. 가상현실 컨트롤러(virtual reality controller)는 사용자와 VR 컨텐츠 간의 상호작용을 지원하는 핵심적인 역할을 한다. 많은 VR 시스템들에서는 실제 장비와 동일한 모양으로 제작된 컨트롤러를 사용할 수 있도록 지원하고 있다. 하지만, 추가 도구를 사용한다는 것은 보다 현실적인 환경의 제공이라는 긍정적인 효과도 있지만, 사용자의 인지적 부담 증가와 같은 부정적인 영향도 있을 수 있다. 본 논문에서는 VR 기반 훈련 시스템 개발에 있어서 다양한 VR 컨트롤러 도구의 사용과 사용자 경험을 ―현존감, 학습 경험, 인지 부하 ― 세 가지 관점에서 다룬다. 이를 위해 자체 VR 소방 훈련 시스템을 개발하였고, 필수 소방 도구를 제작하여 VR 시스템 내에서 실제처럼 조작할 수 있도록 하였으며, 두 번의 사용자 스터디(user study)를 통해 기본 컨트롤러 기반의 시스템(standard), 실제 도구가 적용된 VR 시스템(real tools), 하이브리드(hybrid) 시스템에서의 사용자 경험을 분석하였다. 실험 결과, hybrid 방식이 기존 방식들에 비하여 더 높은 수준의 현존감 및 학습성을, 기본 컨트롤러와 비슷한 수준의 인지 부하를 보였다. 이는 다수의 실제 도구를 사용하는 것이 반드시 더 높은 수준의 사용자 경험을 보장할 수 있는 것이 아님을 보여주며, VR 시스템의 컨트롤러 개발 및 활용의 전략적인 접근이 필요함을 시사한다.

TMD 제어성능 개선을 위한 ETMD 개발

전승곤 한국지진공학회 2022 한국지진공학회논문집 Vol.26 No.4

The TMD has a simpler structure than other vibration control devices and shows excellent control performance for the standardized vibration occurring in the structure. However, when the vibration cycle of the structure coincides with the vibration cycle of the TMD due to the sudden external loads, the off-tuning occurs, which threatens the structure while increasing the vibration width of the TMD. Therefore, Electromagnetic Tuned Mass Damper (ETMD) was developed as a semi-active TMD that prevents off-tuning while exhibiting excellent control performance like TMD. To verify the control performance of the developed ETMD, the bending behavior control performance evaluation experiment using a simple beam bridge was performed. The experimental method compared the mutual control power by experimenting with the existing TMD method and the developed ETMD under nine excitation frequency conditions. As a result, it was confirmed that the control effect of ETMD was about 4.85% higher than that of TMD at 3.02Hz, which generates the maximum displacement in the simple beam bridge. Also, the off-tuning occurred in some excitation conditions when using TMD, although the off-tuning did not occur when using ETMD. Therefore, the excellent control performance of the ETMD developed in this study was verified.

구조물 스마트제어를 위한 ETMD(Electromagnetic Tuned Mass Damper)개발

전승곤,허광희,이진옥,이재훈,김대혁 한국구조물진단유지관리공학회 2022 한국구조물진단유지관리공학회 논문집 Vol.26 No.3

The TMD has a simple structure than other vibration control devices and shows excellent control performance for the simple harmonic vibration generated in the structure. However, the vibration control range is narrower than other control devices, making it vulnerable to vibration cycles caused by unexpected external loads. The ETMD developed in this study consisted of Mass with electromagnets. Therefore when supplying a current, the magnetic field is formed to increase the friction force with the friction plate, thereby instantaneously controlling the behavior of the Mass. The experiment was conducted to compare the control performance of the control device by installing the ETMD developed for control performance evaluation in the center of the model simple beam bridge to forced excitation at 3.02 Hz where the maximum bending displacement occurs. As a result of the experiment, ETMD exhibited excellent control performance with a maximum bending displacement attenuation rate of 57.51%. TMD는 다른 진동제어장치에 비해 구조가 단순하며, 구조물에 발생하는 정형화된 형태의 진동에 우수한 제어성능을 보인다. 그러나 다른 제어장치에 비하여 진동제어범위가 좁아 예상치 못한 외부하중으로 인하여 발생하는 진동주기에는 취약하다. 본 연구에서 개발된 ETMD는 Mass를 전자석으로 구성하여 전류를 공급할 때 자기장이 형성됨과 동시에 마찰판과의 마찰력을 상승시켜 Mass의 거동을 순간적으로 제어한다. 개발된 ETMD의 제어성능 평가를 위하여 모형 단순보 교량 중앙에 ETMD를 설치한 후 중앙부 최대 수직변위가 발생하는 3.02Hz 조건으로 강제 진동을 발생시켜 휨거동 제어실험을 수행하였다. 실험결과 ETMD는 중앙부 최대 수직변위가 발생하는 3.02Hz에서 변위 감쇠율이 57.51%로 우수한 제어성능을 발휘하며 그 외에 진동주기에도 안정적인 제어성능을 보이는 것을 확인하였다.

EMRF를 이용한 개선된 Semi-Active Damper 개발

전승곤 한국지진공학회 2022 한국지진공학회논문집 Vol.26 No.4

Magneto-Rheological Fluid (MRF) is a functional fluid in which flow characteristics change into magnetic force due to its magnetic particles. When the semi-active control device does not use MRF for a long time, precipitation of magnetic particles and abnormal control force occur. Thus, Electro Magneto-Rheological Fluid (EMRF), which improves the precipitation of magnetic particles for MRF and exhibits existing control performance, was developed in this study. First, the optimal mix proportion ratio was selected by conducting a precipitation experiment and a controlled force test by varying the content of grease based on the existing MRF components. Also, EMRF was applied to the shear-type damper to evaluate the control performance when applied to the control device. The cylinder-type damper was developed to apply to the structure, and control performance evaluation was conducted. The result confirmed that the precipitation of the magnetic particles was improved, while the damper using EMRF exhibited excellent control performance.

7 경간 강박스 거더교량의 진동특성 분석

전승곤(Jeon, Seung Gon),허광희(Heo, Gwang Hee),서상구(Seo, Sang Gu),방건혁(Bang, Geon Hyeok),이재훈(Lee, Jae Hoon),박성윤(Park, Sung Yoon) 대한토목학회 2022 대한토목학회 학술대회 Vol.2022 No.10

기계학습 및 네트워크 기반 상병-처방 추천 모델 및 시스템 개발

전승곤(Seunggon Jeon),임소영(Soyoung Rhim),한경식(Kyungsik Han) 한국HCI학회 2018 한국HCI학회 학술대회 Vol.2018 No.1

오늘날 병원에서는 매일 방대한 양의 환자 데이터가 생성된다. 특히 상병과 처방에 대한 기록은 국가적으로 관리 및 검토되고, 모든 병원은 상병과 처방에 대한 기록을 매년 보고하도록 되어 있어, 상병-처방 기록 및 관리는 매우 중요하다. 그러나 우리는 현재의 상병과 처방 기록 관리 시스템에는 상병과 처방의 관계 파악에 대한 두가지 제약사항(정보 누락 및 관계 파악)이 존재하는 것을 확인했다. 이를 해결하기 위해 우리는 기계학습 및 네트워크 기반의 높은 성능을 가지는 상병-처방 추천 모델을 구축하였고, 추천 시스템을 개발하였다.

구조물의 진동제어를 위한 MR-damper의 최적 제어력 산정

허광희,전승곤,김충길,전준용,이진옥,서상구 한국지진공학회 2016 한국지진공학회논문집 Vol.20 No.3

In the case where a MR-damper is employed for vibration control, it is important to decide on how much control capacity should be assigned to it against structural capacities (strength and load, etc). This paper aims to present a MR-damper's control capacity suitable for the capacities of the structure which needs to be controlled. First, a two span bridge was built equipped with a MR-damper, which constitutes a two-span MR-damper control system. Then, inflicting an earthquake load on the system, a basic experiment was performed for vibration control, and a simulation was also carried out reflecting specific control conditions such as MR-damper and rubber bearing. The comparison of the results against each other proved their validity. Then, in order to calculate an optimal control capacity of the MR-damper, structural capacity was divided into eleven cases in total and simulated. For each case, an additional load of 30 KN was inflicted everytime, thereby increasingly strengthening structural capacity. As a result of the study, it was found that the control capacity of MR-damper of 30 KN was safely secured only with lumped mass of more than 150 KN(case 6). Therefore, it is concluded the MR-damper showed the best performance of control when it exerted its capacity at around 20% of structural capacity.

전단형 MR 댐퍼 및 Clipped-optimal 제어알고리즘을 이용한 사장교의 실시간 준능동 진동제어

허광희,전준용,전승곤 한국지진공학회 2016 한국지진공학회논문집 Vol.20 No.2

This paper is concerned with an experimental research to control of random vibration caused by external loads specially in cable-stayed bridges which tend to be structurally flexible. For the vibration control, we produced a model structure modelled on Seohae Grand Bridge, and we designed a shear type MR damper. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and clipped-optimal control. Its control performance was evaluated in terms of the absolute maximum displacements, RMS displacements, the absolute maximum accelerations, RMS accelerations, and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, clipped-optimal control method turned out to be the most effective to reduces of displacements, accelerations, and external power. Finally, It is proven that the clipped-optimal control method was effective and useful in the vibration control employing a semi-active devices such MR damper.

Examining the Application of Human_Computer Interaction in VR Research

Jeon Seunggon(전승곤),Han Jaeho(한재호),Han Kyungsik(한경식) 한국통신학회 2019 한국통신학회 학술대회논문집 Vol.2019 No.1

준능동 진동 제어를 위한 MR 감쇠기의 동적 모델링을 통한 특성분석

허광희,전승곤 한국구조물진단유지관리공학회 2013 한국구조물진단유지관리공학회 논문집 Vol.17 No.6

본 연구에서는 준능동 진동 제어를 위한 MR 감쇠기의 동적 모델링을 통한 특성을 분석 및 평가하였다. 실제 구조물 크기의 모형구조물을 진동제어하기 위하여 Semi-active 성능의 MR Damper를 설계/제작 하였다. 일반적으로 MR Damper를 이용한 준능동 제어 시스템을 구축하기 위해서는 감쇠장치의 발생 감쇠력 및 거동 성향 등의 데이터를 수치적으로 나타낼 수 있는 동적 모델이 요구된다. 따라서 본 연구에서는 MR Damper의 동적거동을 예측/평가 할 수 있는 모델링을 하기 위하여 다양한 동적 모델 중Power 모델 및 Bingham 모델을 적용하였다. 이때 동적 모델과 비교/평가하기 위하여 개발된 MR Damper의 동하중 실험을 수행하였다. 동하중 실험조건은 가진 주파수를(0.15Hz, 1.0Hz, 2.0Hz) 선정하고, 주파수별 각각 3가지씩 가진 속도를 달리하여, 변위가 감쇠력에 미치는 영향력을 확인하였다. 이렇게 얻어진 MR Damper의 동하중실험 결과를 적용하여 각 동적 모델 별 모델변수를 규명하였고, 이를 바탕으로 힘-속도 관계곡선 및 예측된 발생 감쇠력을 산출하였으며, 산출된 결과와 개발된 MR Damper의 실험 결과를 상호 비교·평가하였다. 최종적으로 본 연구에서 개발한 MR Damper는 준능동 제어장치로 활용 가능함을 확인 하였고, 다양한 변위를 이용한 실험을 통하여 정상적인 진동제어를 위해서는 최소 2mm 이상의 변위가 확보되어야 한다는 결과를 얻었다. This research is aimed to evaluate characteristics and dynamic modeling of MR damper for semi-active vibration control. A MR damper of semi-active type was designed and made for the purpose of controlling the vibration of a real-size model structure. Usually a semi-active control system equipped with a MR damper requires a dynamic model which expresses numerical data about the damping capacity and dynamic characteristics generated by a MR damper. To fulfil the requirement, a Power model and a Bingham model were particularly employed among many dynamic models of MR damper. Those models being contrasted with other ones, a dynamic test was carried out on the developed MR damper. In the test, excitation frequencies were conditioned to be 0.15 Hz, 1.0 Hz, and 2.0 Hz, and three different currents were adopted for each frequency. From these test results, it was found that displacement affected control capacity of the MR damper. The test results led to the identification of model variables for each dynamic model, on the basis of which a force-speed relation curve and expected damping force were derived and contrasted to those of the developed MR damper. Therefore, it was proven that the MR damper designed and made in this research was effective as a semi-active controller, and also that displacement of 2mm at minimum was found to be secured for vibration control, through the test using various displacements.