• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.12-18
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• 1999

A deformable non-Uniform Rational B-Spline (NURBS) based volume is programed for the force reflecting exoskeleton haptic device. In this work, a direct free form deformation (DFFD) technique is applied for the realistic manipulation. In order to implement the real-time deformation, a nodal mapping technique is used to connect points on the virtual object with the NURBS volume. This geometric modeling technique is ideally incorporated with the force reflecting haptic device as a virtual interface. The results in this work introduce details for the complete set-up for the realistic virtual clay modeling task with force feedback. The force reflecting exoskeleton haptic manipulator, coupled with a supporting PUMA 560 manipulator and the virtual clay model are integrated with the graphics display, and results show that the force feedback from the realistic physically based virtual environment can greately enhance the sense of immersion.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.395-402
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• 2005

This paper deals with modeling and computer simulation of a full multibody vehicle model for a driving simulator. The multibody vehicle model is based on the recursive formulation and a corresponding simulation code is generated automatically from AUTOCODE, which is a symbolic computation package developed by the authors using MAPLE. The paper describes a procedure for automatically generating a highly efficient simulation code for the full vehicle model, while incorporating realistically modeled components. The following issues have been accounted for in the procedure, including software design for representing a mechanical system in symbolic form as a set of computer data objects, a multibody formulation for systems with various types of connections between bodies, automatic manipulation of symbolic expressions in the multibody formulation, interface design for allowing users to describe unconventional force-and torque-producing components, and a method for accommodating external computer subroutines that may have already been developed. The effectiveness and efficiency of the proposed method have been demonstrated by the simulation code developed and implemented for driving simulation.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.11a
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• pp.30-35
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• 2001

CAVE 시스템은 다수의 프로젝션 장비들을 사용하여, 물리적으로 사용자를 둘러싼 각 면에 영상을 투사하여 사용자에게 현실감을 제공하는 통합환경이다. 본 논문은 CAVE 시스템을 실제 구축하여 보고, 시스템을 구축하는데 있어 문제가 되는 각 면에서의 영상의 초기 설정의 보정 문제, 다수의 영상이 사용자의 시점에서 왜곡되지 않고 현실화되도록 하는 알고리즘과, 사용자의 시점을 찾기 위한 위치 추적 장비의 정확성 문제와 시점에 대한 보정 문제, 사용자가 가상 공간을 운용할수 있도록 하는 장비들의 사용 환경 설계 문제 등을 해결하는 방법에 대하여 연구하였다. 또한, 본 논문은 CAVE 시스템 안에서 각 장비들이 전체적으로 조율 되어 운용되는 방법을 제시한다.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.27-32
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• 2018

Purpose: This study was performed to investigate processability of the dental zirconia block. Most of the CAD/CAM zirconia restorations utilize the partially sintered blocks, which are sintered at a temperature lower than $1100^{\circ}C$. Methods: Partially sintered zirconia samples were prepared $40{\times}30{\times}10mm$ and surface treatment by #2000 sandpaper. Scratch hardness was determined by the procedure of ASTM G171-03 using a scratch hardness tester(KS TECH, Korea) equipped with a real time load detector to measure tangential force during scratching. The scratch rate was 30 mm/min. Results: Scratch hardness(Hs) increases steeply with increase in the loads. The highest Hs was sampl 1.42 GPa and lowest was sample 0.42 GPa. Conclusion : The machinability of partially sintered CAD/CAM zirconia blocks can be optivized by manipulation of Hs.

• International Journal of Control, Automation, and Systems
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• v.2 no.4
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• pp.494-500
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• 2004

The wing rock phenomenon is a high angle of attack aerodynamic motion manifested by limit cycle roll oscillations. Experimental studies reveal that direct control and manipulation of leading edge vortices, through the use of 'blowing' techniques is effective in the suppression of wing rock. This paper presents the design of a robust controller for the experimental implementation of one such 'blowing' technique - recessed angle spanwise blowing (RASB), to achieve wing rock suppression over a range of operating conditions. The robust controller employs Takagi - Sugeno fuzzy system, which is fine-tuned by experimental simulations. Performance of the controller is assessed by real-time wind tunnel experiments with an 80 degree swept back delta wing. Robustness is demonstrated by the suppression of wing rock at a range of angles of attack and free stream velocities. Numerical simulation results are used to further substantiate the experimental findings.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.110-113
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• 2003

In this paper, the multi-channel high speed data acquisition system is implemented. This high speed signal processing system for 3-D image display is applicable to the manipulation of a medical image processing, multimedia data and various fields of digital image processing. In order to convert the analog signal into digital one, A/D conversion circuit is designed. PCI interface method is designed and implemented, which is capable of transmission a large amount of data to computer. In order to, especially, channel extendibility of images acquisition, bus communication method is selected. By using this bus method, we can interface each module effectively. In this paper, 32-channel A/D conversion and PCI interface system for 3-dimensional and real-time display of the retina image is developed. The 32-channel image acquisition system and high speed data transmission system developed in this paper is applicable to not only medical image processing as 3-D representation of retina image but also various fields of industrial image processing in which the multi-point realtime image acquisition system is needed.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.7-7
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• 1992

Extending discrete event modelling formalisms to facilitate greater symbol manipulation capabilities is important to further their use in intelligent control and design of high autonomy systems. This paper defines an extension to the DEVS formalism that facilitates symbolic expression of discrete event times by extending the time base from the real numbers to the field of linear polynomials over the reals. A simulation algorithm is developed to generate the branching trajectories resulting from the underlying non-determinism. To efficiently manage linear polynomial constraints based on feasibility checking algorithm borrowed from linear programming. The extended formalism offers a convenient means to conduct multiple, simultaneous explorations of model behaviors. Examples of application are given with consideration on fault model analysis.

• Archives of design research
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• v.19 no.4 s.66
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• pp.71-80
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• 2006

Collaboration has become essential in the product design process due to internationalized and specialized business environments. This study presents a real-time collaborative 3D design workspace for distributed designers, focusing on the development and the evaluation of new interaction techniques supporting nonverbal communication such as awareness of participants, shared manipulation and tele-presence. Requirements were identified in terms of shared objects, shared workspaces and awareness through literature reviews and an observational study. An Augmented Reality based collaborative design workspace was developed, in which two main interaction techniques, Turn-table and Virtual Shadow, were incorporated to support shared manipulation and tele-presence. Turn-table provides intuitive shared manipulation of 3D models and physical cues for awareness of remote participants. Virtual shadow supports natural and continuous awareness of location, gestures and pointing of partners. A lab-based evaluation was conducted and the results showed that interaction techniques effectively supported awareness of general pointing and facilitated discussion in 3D model reviews. The workspace and the interaction techniques can facilitate more natural communication and increase the efficiency of collaboration on virtual 3D models between distributed participants (designer-designer, engineer, or modeler) in collaborative design environments.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.2
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• pp.73-81
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• 2024

Recently, mobile manipulators have been utilized in agriculture industry for weed removal and harvest automation. This paper proposes a domain adaptive fruit detection method for harvest automation, by utilizing OWL-ViT model which is an open-vocabulary object detection model. The vision-language model can detect objects based on text prompt, and therefore, it can be extended to detect objects of undefined categories. In the development of deep learning models for real-world problems, constructing a large-scale labeled dataset is a time-consuming task and heavily relies on human effort. To reduce the labor-intensive workload, we utilized a large-scale public dataset as a source domain data and employed a domain adaptation method. Adversarial learning was conducted between a domain discriminator and feature extractor to reduce the gap between the distribution of feature vectors from the source domain and our target domain data. We collected a target domain dataset in a real-like environment and conducted experiments to demonstrate the effectiveness of the proposed method. In experiments, the domain adaptation method improved the AP50 metric from 38.88% to 78.59% for detecting objects within the range of 2m, and we achieved 81.7% of manipulation success rate.

• Journal of IKEEE
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• v.25 no.2
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• pp.285-290
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• 2021

The existing aiming inspection use foreign-made aiming inspection equipment. However, the quantity is insufficient and the difficult to maintain. So it takes a lot of time to inspect the target. This system can reduces the time of aiming inspection and be maintained and distributed smoothly because it is a domestic product. In this paper, we develop a system that can detect targets and monitor shooting results through a target detection deep learning model. The system is capable of real-time detection of targets and has significantly increased the identification rate through several preprocessing of distant targets. In addition, a graphical user interface is configured to facilitate user camera manipulation and storage and management of training result data. Therefore the system can replace the currently used aiming inspection equipment and non-fire training.