• Journal of Cadastre & Land InformatiX
• /
• v.52 no.2
• /
• pp.171-187
• /
• 2022

Recently, the demand and development for non-face-to-face services are rapidly progressing due to the pandemic caused by the COVID-19, and attention is focused on the metaverse at the center. Entering the era of the 4th industrial revolution, Metaverse, which means a world beyond virtual and reality, combines various sensing technologies and 3D reconstruction technologies to provide various information and services to users easily and quickly. In particular, due to the miniaturization and economic increase of convergence sensors such as unmanned aerial vehicle(UAV) capable of high-resolution imaging and high-precision LiDAR(Light Detection and Ranging) sensors, research on digital-Twin is actively underway to create and simulate real-life twins. In addition, Game engines in the field of computer graphics are developing into metaverse engines by expanding strong 3D graphics reconstuction and simulation based on dynamic operations. This study constructed a mirror-world type metaverse that reflects real-world coordinate-based reality using Unreal Engine 5, a recently announced metaverse engine, with accurate 3D spatial information data of convergence sensors based on unmanned aerial system(UAS) and LiDAR. and then, spatial information contents and simulations for users were produced based on various public data to verify the accuracy of reconstruction, and through this, it was possible to confirm the construction of a more realistic and highly utilizable metaverse. In addition, when constructing a metaverse that users can intuitively and easily access through the unreal engine, various contents utilization and effectiveness could be confirmed through coordinate-based 3D spatial information with high reproducibility.

• Smart Structures and Systems
• /
• v.8 no.3
• /
• pp.303-320
• /
• 2011

Comparing to active damage monitoring, impact localization on composite by using time reversal focusing method has several difficulties. First, the transfer function of the actuator-sensor path is difficult to be obtained because of the limitation that no impact experiment is permitted to perform on the real structure and the difficulty to model it because the performance of real aircraft composite is much more complicated comparing to metal structure. Second, the position of impact is unknown and can not be controlled as the excitation signal used in the active monitoring. This makes it not applicable to compare the difference between the excitation and the focused signal. Another difficulty is that impact signal is frequency broadband, giving rise to the difficulty to process virtual synthesis because of the highly dispersion nature of frequency broadband Lamb wave in plate-like structure. Aiming at developing a practical method for on-line localization of impact on aircraft composite structure which can take advantage of time reversal focusing and does not rely on the transfer function, a PZT sensor array based phase synthesis time reversal impact imaging method is proposed. The complex Shannon wavelet transform is presented to extract the frequency narrow-band signals from the impact responded signals of PZT sensors. A phase synthesis process of the frequency narrow-band signals is implemented to search the time reversal focusing position on the structure which represents the impact position. Evaluation experiments on a carbon fiber composite structure show that the proposed method realizes the impact imaging and localization with an error less than 1.5 cm. Discussion of the influence of velocity errors and measurement noise is also given in detail.

• The Journal of Korean Association of Computer Education
• /
• v.17 no.2
• /
• pp.65-76
• /
• 2014

This paper aims at implementing experimental devices with which middle school students can explore scientific ideas using GoGo Board and NetLogo that connect real and simulated worlds. Related research literature was reviewed to design a simulation-based learning model using computer simulation and robot-related activities. In order to construct devices for exploratory experiments, GoGo Board was adopted for developing the interface of Micro-Based Laboratory(MBL) devices with several sensors while NetLogo was used for connecting MBL devices (real world) and simulated experiments (virtual world). The simulation contents were developed in the area of heat equilibrium for changing temperature and the conduct-current relationship appeared in the textbook of middle school science class. With the developed device and contents students can visualize the change of temperature cold and hot waters in terms of heat equilibrium. They also can measure the change of conductor representing the relationship between conductor and current. The formative evaluation of the contents carried out with several middle school students indicated the future direction for upgrading simulation contents and interface. The results might be beneficial for science educators who want to apply simulation contents with the use of computers.

• 한국HCI학회:학술대회논문집
• /
• 2006.02a
• /
• pp.124-129
• /
• 2006

음악은 소리를 즐긴다는 뜻을 담고 있다. 감상자에게 단순한 청각적 자극을 넘어 즐거움을 주기 위해선 음악적인 경험이 뒷받침되어야 한다. 가상 현실을 이용한 사용자와 시스템 간의 상호작용을 음악 경험 제공에 접목하려는 시도는, 새로운 경험을 통해 일반인들이 보다 쉽게 음악을 접하고 체험함으로써 음악을 통해 즐거움을 얻을 수 있도록 도움을 주는 데에 그 목적이 있다. 가상 오케스트라를 구현하고 지휘 동작을 재현하는 것은 이러한 가능성을 극대화하는 연구이다. 본 논문에서는 가상 오케스트라를 구현하기 위해 필수적인 중간 단계로, 사용자의 지휘 동작을 감지하여 연주의 박자(속도)를 제어하는 지휘 시뮬레이션 시스템을 제시한다. 실제의 지휘 동작을 분석하고, 동작의 변화를 인식하기 위하여 가속도 센서를 이용, 공간상에서 지휘봉의 움직임을 가속도 정보로 수집하여 이에 상응하는 박자의 제어를 구현한다. 사용자의 박자 명시에 따라 변화하는 상하 방향의 가속도를 센서를 통해 전압 신호로 입력 받고, DSP 의 A/D conversion 모듈에서 디지털 신호로 변환, 일정 수준 이상의 신호를 박자 정보로 직렬통신을 통해 컴퓨터에 전달한다. 컴퓨터에서는 Max/MSP를 이용하여 각 박자 사이의 시간 간격을 측정하고 상응하는 MIDI 음악을 재생하는 방식으로 시스템이 구현된다. 기존 연구에서 사용된 CCD 카메라에 의한 Motion Tracking 을 보완하여 동작의 크기에 따라 음량을 조절한다. 본 논문에서 제시되는 시스템은 지휘 동작에서 가장 특징적으로 나타나는 상하 방향의 급격한 가속도 변화를 직접 입력 받기 때문에 기존 시스템에 비해 지휘 동작의 인식 성공률을 높일 수 있으며, 화상 처리 및 계산에 의한 지연을 최소화할 수 있다. 또한, 장치의 규모를 소형화하여 보다 지휘봉의 형태에 가까운 인터페이스를 제공하며, 적합한 응용 콘텐츠를 접목할 경우 게임 컨트롤러로의 발전 가능성이 있다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.11
• /
• pp.1868-1878
• /
• 2016

This paper proposes a novel velocity estimator for long-term underwater navigation of autonomous underwater vehicles(AUVs). Provided that an external position fix is not given, a viable goal in designing a underwater navigation algorithm is to reduce the divergence rate of position error only using the sporadic velocity information obtained from Doppler velocity log(DVL). For such case, the performance of underwater navigation eventually depends on accuracy and reliability of external velocity information. This motivates us to devise a velocity estimator which can drastically enhance the navigation performance even when the DVL measurement is unavailable. Incorporating the Gertler-Hagen hydrodynamics model of an AUV with the measurement models of velocity and depth sensors, the velocity estimator design problem is resolved using the extended Kalman filter. Different from the existing methods in which an AUV simulator is regarded as a virtual sensor, our approach is less sensitive to the model uncertainty often encountered in practice. This is because our velocity filter estimates the simulator errors with sensor aids and furthermore compensates these errors based on the indirect feedforward manner. Through the simulations for typical AUV navigation scenarios, the effectiveness of the proposed scheme is demonstrated.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.7
• /
• pp.1445-1451
• /
• 2005

Home-Network is an integrated network of the PC and all electric home appliances in the home so that they can communicate with each other. In the 21th century, here are various technology for Home Network environment such as HomePNA, IEEE 1394, Ethernet Lan and Bluetooth. For Home Network construction, generally, the standard series interface 'RS232' is used to make communication possible between electric home appliances. However Home network using RS232 has a problem. That is, All machines have to be connected to each other with RS232 using Point-to-Point mode. In this case, the system becomes complicated because we have to use circuits as much as there are machines and increased expenses. To improve this problem, In this thesis, designed home network using RS422 Multi-drop mode serial communication and controled it with embedded linux system. And connected RS422 with motors and sensors using PIC to make the home network virtual environment.

• KIPS Transactions on Software and Data Engineering
• /
• v.4 no.2
• /
• pp.91-96
• /
• 2015

We propose AirPincher, a handheld pointing device for recognizing delicate mid-air hand gestures to control a remote display. AirPincher is designed to overcome disadvantages of the two kinds of existing hand gesture-aware techniques such as glove-based and vision-based. The glove-based techniques cause cumbersomeness of wearing gloves every time and the vision-based techniques incur performance dependence on distance between a user and a remote display. AirPincher allows a user to hold the device in one hand and to generate several delicate finger gestures. The gestures are captured by several sensors proximately embedded into AirPincher. These features help AirPincher avoid the aforementioned disadvantages of the existing techniques. We experimentally find an efficient size of the virtual input space and evaluate two types of pointing interfaces with AirPincher for a remote display. Our experiments suggest appropriate configurations to use the proposed device.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1938-1943
• /
• 2005

Network human-robot interface is an important research topic. In home application, users access the robotic system directly via voice, gestures or through the network. Users explore a system by using the services provided by this system and to some extend users are enable to participate in a service as partners. A service may be provided by a robot, a group of robots or robots and other network connected systems (distributed sensors, information systems, etc). All these services are done in the network environment, where uncertainty such as the unstable network connection, the availability of the partners in a service, exists. Moreover, these services are controlled by several users, accessing at different time by different methods. Our research aimed at solving this problem to provide a high available level, flexible coordination system. In this paper, a multi-agent framework is proposed. This framework is validated by using our new concept of slave agents, a responsive multi-agent environment, a virtual directory facilitator (VDF), and a task allocation system using contract net protocol. Our system uses a mixed model between distributed and centralized model. It uses a centralized agent management system (AMS) to control the overall system. However, the partners and users may be distributed agents connected to the center through agent communication or centralized at the AMS container using the slave agents to represent the physical agents. The system is able to determine the task allocation for a group of robot working as a team to provide a service. A number of experiments have been conducted successfully in our lab environment using Issac robot, a PDA for user agent and a wireless network system, operated under our multi agent framework control. The experiments show that this framework works well and provides some advantages to existing systems.

• Spatial Information Research
• /
• v.16 no.4
• /
• pp.479-488
• /
• 2008

This paper performs investigation of the state-of-the-art approaches to building extraction in terms of their sensory input data and methodologies. For the last decades, there have been many types of sensory input data introduced into the mapping science and engineering field, which are considerably diverse in aspects of spatial resolution and data processing. With the cutting-edge technology in this field, accordingly, one of the key issues in GIS is to reconstruct three -dimensional virtual models of the real world to meet the requirements occurring in spatial applications such as urban design, disaster management, and civil works. Thus, this study investigates the strengths and weaknesses of previous approaches to automating building extraction with two categories - building detection and modeling and with sensor types categorized. The findings in this study can be utilized in enhancing automation algorithms and choosing suitable sensors, so that they can be optimized for a specific purpose.

• Journal of the Korean Society for Precision Engineering
• /
• v.34 no.1
• /
• pp.41-46
• /
• 2017

Magnetically levitated (Maglev) vehicles maintain a constant air gap between guideway and car bogie, and thereby achieves non-contact riding. Since the straightness and the flatness of the guideway directly affect the stability of levitation as well as the ride comfort, it is necessary to monitor the status of the guideway and to alert the train operators to any abnormal conditions. In order to develop a signal processing algorithm that extracts guideway irregularities from sensor data, virtual testing using a simulation model would be convenient for analyzing the exact effects of any input as long as the model describes the actual system accurately. Simulation model can also be used as an estimation model. In this paper, we develop a state-space dynamic model of a maglev vehicle system, running on the guideway that contains jumps. This model contains not only the dynamics of the vehicle, but also the descriptions of the power amplifier, the anti-aliasing filter and the sampling delay. A test rig is built for the validation of the model. The test rig consists of a small-scale maglev vehicle, tracks with artificial jumps, and various sensors measuring displacements, accelerations, and coil currents. The experimental data matches well with those from the simulation model, indicating the validity of the model.