• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1253-1263
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• 2002

The control system design and modeling of an unmanned vehicle by means of a new concept for better performance through a tole-operation system is suggested by sensor fusion. But, the control of a real vehicle is very difficult, because the system identification of the vehicle is hard to find the unknown factors and the disturbances of the experimental environment. For the longitudinal and lateral controls, the traction system and steering system models are set up and a tuning method to find the gain of the controller by experiments is presented. In this research, mechanical and electronic parts are implemented to operate the unmanned vehicle and data reconstruction method of information about the environment data coming from several sensors is presented by data plot for the vehicle navigation. This paper focuses on the integration of tole-operated unmanned vehicle. This vehicle mainly controlled lateral and longitudinal directions with actuators for controlling vehicle movement and sensors for the closed-loop controlled system.

• Computers and Concrete
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• v.20 no.3
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• pp.297-310
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• 2017

A CFD software was used to simulate free surface flow of SCC in the T-Box test. In total, seven simulations were developed to study the effect of rheological parameters on the non-restricted flow performance of SCC in both horizontal and vertical directions. Different suspending fluids having five plastic viscosity values between 10 and 50 Pa.s, three yield stress values between 14 and 75 Pa, one density of $2500kg/m^3$, and one shear elasticity modulus of 100 Pa were considered for suspension of 178 spherical particles of 20-mm diameter and $2500kg/m^3$ density. The results of the simulations are found to correlate well to changes in rheological parameters of the suspending fluid. Plastic viscosity was shown to be the most dominant parameter affecting flowability and dynamic stability compared to the yield stress. A new approach was proposed to evaluate performability of SCC based on a trade-off between flowability and dynamic stability.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.53-61
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• 2005

This study reviewed research and design directions on VR-Tangible interaction and explored market-driven approach of VR-tangible interaction applications. As a case study, we studied autism remedy system based on VR-tangible interaction design. Literature and field study has done on autism and its remedy methodologies. Based on observation process about patients, therapists, and remedy programs, interaction factors for autism remedy are found and then design strategy, system configuration, and remedy contents scenarios are set up to solve time and resource problems, presence problems, and efficiency issues of remedy results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.10
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• pp.1619-1625
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• 1997

This paper concerns a 2-axis PR type pneumatic manipulator system translating in vertical and rotating in horizontal directions. A simplified linear model is mathematically formulated similar to the pneumatic acturators in dynamic responses in order to devise an appropriate position control scheme. A PD controller preceding the on/off solenoid valve turns out not only economical but also effective in reducing rise time and amplitude of limit cycles, if its control gains are determined on the basis of frequency response. And, additional implementation of symmetric or asymmetric deadband at the PD controller output greatly helps minimize valve opening numbers, positional error, and undesirable direction-dependent property due to the gravitational load. Such a control concept is synthesized through numerical simulations and next applied to the experimental set-up, featuring enhanced positional servo characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.7
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• pp.956-965
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• 1998

Hot-wire measurement of the longitudinal and radial velocity components and Reynolds stresses are reported for developing turbulent flow in a strongly curved 180 deg. pipe and its tangents. Slanted wire is rotated to 6 directions and the voltage outputs of them are combined to obtain the mean velocities and Reynolds stresses. Significant double maxima in the longitudinal velocity component appear in the bend. V-profiles reveal the development of a strong secondary flow. This secondary flow is induced by the transverse pressure gradient set up between the outer(r$\sub$o/) and inner(r$\sub$i/) wall region of the bend. Another second cross-stream flow develops after .theta.=135 deg. and its direction is opposed to that of main second flow.

• Journal of Food Hygiene and Safety
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• v.24 no.4
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• pp.398-407
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• 2009

In modern diet relying heavily on processed food, it is difficult to live without food additives, added to food regardless of whether consumers want or not. This poses the following questions: Are food additives really safe? Are they toxic? Are they cancerous? Are they still good to eat? Are there any concerns on excessive intake and interactions? Is toxicity testing adequate? Is ADI evaluation being set up properly? In this article, I discuss a desirable management strategy for food additives, by addressing these questions and concerns and analyzing and reviewing current status of food additive management.

• Korean Institute of Interior Design Journal
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• no.29
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• pp.112-119
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• 2001

In general, the definition of criticism is making a constructive analysis between good & evil, right & wrong, and beauty & ugliness. Just as the literature, art, music, and architecture welcomes productive criticism in order for further advancement in each professional field, constructive criticism in the field of interior architecture must be activated stance it would be as useful as in other fields to upgrade the level of design quality If the constructive criticism were to be taken properly in the benefit of further advancement in particular design, then the criticism must hale a proper criteria in order to examine and review the design work objectively However, as the design symbolizes cultural interpretation and reaction towards better creativity, we expect design to be mutated in many different directions. As the limit of Interior architecture shares limitless possibilities in today's society, it seems that we need to set up a guidelines of design criticism in order to support the further development of the area of interior architecture.

• Electronics and Telecommunications Trends
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• v.34 no.4
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• pp.32-42
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• 2019

The performance of machine learning algorithms significantly depends on how a configuration of hyperparameters is identified and how a neural network architecture is designed. However, this requires expert knowledge of relevant task domains and a prohibitive computation time. To optimize these two processes using minimal effort, many studies have investigated automated machine learning in recent years. This paper reviews the conventional random, grid, and Bayesian methods for hyperparameter optimization (HPO) and addresses its recent approaches, which speeds up the identification of the best set of hyperparameters. We further investigate existing neural architecture search (NAS) techniques based on evolutionary algorithms, reinforcement learning, and gradient derivatives and analyze their theoretical characteristics and performance results. Moreover, future research directions and challenges in HPO and NAS are described.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.22-24
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• 2018

MPEG-I Visual group is actively working on enhancing immersive experiences with up to six degree of freedom (6DoF). In virtual space of omnidirectional 6DoF, which is defined as a case of degree of freedom providing 6DoF in a restricted area, looking at the scene from another viewpoint (another position in space) requires rendering additional viewpoints called virtual omnidirectional viewpoints. This paper presents the performance analysis on view synthesis, which is done as the exploration experiment (EE) in MPEG-I, from a set of 360 videos providing omnidirectional 6DoF in various ways with different distances, directions, and number of input views. In addition, we compared the subjective quality between synthesized images with one input view and two input views.

• Wind and Structures
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• v.34 no.3
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• pp.259-274
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• 2022

The present paper is focused on analyzing a set of Computational Fluid Dynamics (CFD) simulation data on reducing orthogonal peak base moment coefficients on a high-rise rectangular building with wings. The study adopts an aerodynamic optimization procedure (AOP) composed of CFD, artificial neural network (ANN), and genetic algorithm (G.A.). A parametric study is primarily accomplished by altering the wing positions with 3D transient CFD analysis using k - ε turbulence models. The CFD technique is validated by taking up a wind tunnel test. The required design parameters are obtained at each design point and used for training ANN. The trained ANN models are used as surrogates to conduct optimization studies using G.A. Two single-objective optimizations are performed to minimize the peak base moment coefficients in the individual directions. An additional multiobjective optimization is implemented with the motivation of diminishing the two orthogonal peak base moments concurrently. Pareto-optimal solutions specifying the preferred building shapes are offered.