• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.172-181
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• 2023

In this study, real-time damage evaluation of cable-stayed bridges was conducted for cable damage. ICP type acceleration sensors were used for real-time damage assessment of cable-stayed bridges, and Kinetic Energy Optimization Techniques (KEOT) were used to select the optimal conditions for the location and quantity of the sensors. When a structure vibrates by an external force, KEOT measures the value of the maximum deformation energy to determine the optimal measurement position and the quantity of sensors. The damage conditions in this study were limited to cable breakage, and cable damage was caused by dividing the cable-stayed bridge into four sections. Through FE structural analysis, a virtual model similar to the actual model was created in the real-time damage evaluation method of cable. After applying random oscillation waves to the generated virtual model and model structure, cable damage to the model structure was caused. The two data were compared by defining the response output from the virtual model as a corruption-free response and the response measured from the real model as a corruption-free data. The degree of damage was evaluated by applying the data of the damaged cable-stayed bridge to the Improved Mahalanobis Distance (IMD) theory from the data of the intact cable-stayed bridge. As a result of evaluating damage with IMD theory, it was identified as a useful damage evaluation technology that can properly find damage by section in real time and apply it to real-time monitoring.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.753-759
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• 2006

햅틱인터페이스 기술을 이용하면 가상물체의 형태를 만져보고 느껴볼 수 있다. 물체마다 다른 수학적 마찰력 모델을 적용하여 실감있는 마찰력 표현도 가능하다. 그러나 각 물체에 해당하는 마찰력 모델을 선정하는 것과 적절한 마찰계수 등을 반복적 실험을 통하여 알아내는 것은 쉽지 않다. 실제 물체의 마찰력이 알려진 마찰력 모델과 다르다면 수학적 모델로 표현할 수 없는 경우도 있다. 본 논문에서는 신경회로망 학습을 이용하여 마찰력 모델의 선택이나 마찰계수 등을 정하는 과정 없이 실제 물체의 마찰력을 표현하는 방법을 제시하고 있다. 상용 햅틱인터페이스 장치인 PHANToM 2 대를 이용하여 마찰력 획득 시스템을 구성하고 고무판, 종이 등의 물체 표면에서의 속도와 물체에 작용하는 힘을 획득하여 가공한 데이터를 입력 및 출력으로 갖는 신경회로망을 통해 학습시킨 후 OpenGL로 구현한 가상물체에 적용하여 보았다. Force/Torque 센서를 사용하지 못한 일부 문제가 있었으나 예상보다 사실적인 마찰력을 표현할 수 있었다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.207-208
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• 2016

본 논문에서는 아두이노와 블루투스 모듈이 결합된 블루이노2 보드를 활용한 컨트롤러를 제작하였다. 컨트롤러는 버튼, 아날로그 조이스틱, 자이로 센서로 구성되어 있으며 각 부품의 데이터 값을 블루투스로 전송하면 유니티 엔진을 이용하여 제작된 게임이 작동되는 것이다. 컨트롤러와 함께 구글 카드보드를 이용한 스마트폰으로 가상현실 게임을 체험 할 수 있게 된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.789-792
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• 2016

사물인터넷 시장의 발전에 따라 많은 통신 프로토콜과 그에 해당하는 장비들이 발전을 하고 있다. 다양한 통신 프로토콜 사용에 따라 이질성 문제가 대두되어 이를 해결하는 미들웨어 기반의 가상 어댑터들이 나왔다. 하지만 이러한 가상 어댑터들은 통신 프로토콜 간의 이질성 문제는 해결하지만 인터넷 같은 외부 망과는 상호 호환이 안 되는 문제가 있다. 본 논문에서는 MQTT(Message Queuing Telemetry)를 활용하여 기존 가상 어댑터들과 외부 망 간 양방향 연동을 가능케 하는 MQTT 어댑터를 제안한다. 본 연구를 통하여 어댑터는 내부 센서 데이터 활용뿐만 아니라 외부 망의 데이터도 활용할 수 있어 폭넓은 상호 운용성을 확보할 수 있다.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.73-79
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• 2003

Recently, the tole-robot operations to an unstructured environment have been widely researched. The human's interaction with the tole-robot system can be used to improve robot operation and performance for an unknown environment. The exact modeling based on real environment is fundamental and important process for this interaction. In this paper, we propose an extrinsic parameter calibration and data augmentation method that only uses a circular jig in the hand-eye laser virtual environment. Compared to other methods, easier estimation and overlay can be done by this algorithm. Experimental results using synthetic graphic demonstrate the usefulness of the proposed algorithm.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1665-1667
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• 2015

본 논문은 운전자의 안전운전 지원을 위하여 실세계 자동차 외부에 위치한 카메라와 RADAR 센서들에서 취득하는 정보들을 통하여 가상세계에 운전 환경의 실세계를 그대로 재현하여 활용하는 기술을 소개한다. 이 기술은 운전상황의 제한된 인터페이싱 상황과 짧은 주의집중 시간에 모든 정보를 정확하게 전달하기 위하여, 직관적이고 효과적 전달이 가능한 복합 멀티미디어 - 동영상 및 간단한 텍스트 정보 - 의 형태를 활용한다. 이러한 융합 미디어 기반 운전정보 지원 서비스는 실시간 운전 상황에 대한 운전자의 이해와 대응력을 높여 안전운전에 기여할 수 있을 것이다.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.358-366
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• 2006

This paper describes a novel navigation algorithm using a locomotion interface with two 6-DOF programmable foot platforms. When a human walks on the locomotion interface (LI), the walking motions of the human are recognized by several sensors. Then, the sensed information is used by the LI for generation of infinite surfaces for continuous walking and the virtual environments for scene update according to motions of the human walking. The suggested novel navigation system can induce user's real walking and generate realistic visual feedback during navigation. A novel navigation algorithm is suggested to allow natural navigation in virtual environments by utilizing conditions of normal gait analysis. For realistic visual feedback, the virtual environment is designed with three components; 3D object modeler for buildings and terrains, scene manager and communication manager component. From experiments, the subjects were satisfied with the reality of the suggested navigation algorithm using the locomotion interface. Therefore, the suggested navigation system can allow a user to explore into various virtual terrains with real walking and realistic visual feedback.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.3
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• pp.101-106
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• 2020

The utilization of virtual reality is increasing not only in games but also in medical care such as rehabilitation. Due to the convenience, the motion of the upper limb is detected using a non-contact method using video or a handheld type mouse, etc. In this paper, we implemented a glove which can measure finger movements and upper limb movements by using flex sensors whose resistance value changes according to the degree of folding and inertial sensors which can obtain direction information in space. We showed the upper arm movements including finger movements with signals obtained from the implemented glove on the open software platform, Processing. The sensitivity of each finger movement was 0.5deg, and the sensitivity of the upper limb motion was 0.6deg.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.171-179
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• 2003

In this paper a neural network-based fault tolerant control system for aircraft sensor and actuator failures is considered. By exploiting flight dynamic relations a set of neural networks is constructed to detect sensor failure and give alternative signal for the faulty sensor. For actuator failures another set of neural networks is designed to perform fault detection, identification, and accomodation which returns the aircraft to a new stable trim. Integrated system is simulated to show the performance of the system with sensor and control surface failures.

• Journal of Korea Spatial Information System Society
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• v.9 no.1
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• pp.31-43
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• 2007

Sensor data have the characteristics such as numerous and continuous data. Therefore, it is required to develop an index which could retrieve a specific sensor data efficiently from numerous sensed data. The index should have an efficient delete operation for the past data to support the data archiving. In this paper, we have proposed and implemented an index splitting technique to support the sensor data archiving. These splitted indexes compose of a virtual index (that is, index management component), which is shown as single tree from outside. Experimental results show that in the case of 100,000 insert operations the splitted index performs 8% better than the traditional TB-tree maximumly. And the splitted index outperforms TB-tree with retrieving queries when the region of query is small and the size of time domain is large.