• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.67-73
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• 2005

This paper describes depth, heading and speed control of an underwater vehicle that has four stern thrusters of which forces are coupled in the diving and, steering motion, as well as the speed of the vehicle. The optimal linear quadratic controller is designed based on a linearized- state space model, developed by combining the dynamic equations of speed, steering and diving motion. The designed controller gives provides an optimal thrust distribution, minimizing the given performance index to control speed, depth and heading simultaneously. To validate the performance of the controller, a simulation and tank-test are carried out with DUSAUV (Dual Use Semi-Autonomous Underwater Vehicle), developed by KORDI as a test-bed for testing new underwater technologies. Optimal gains of the controller are tuned, using a computer simulation environment with a nonlinear 6-DOF numerical DUSAUV model, developed by PMM (Planner Motion Mechanism) test. To verify the performance of the presented controller in experiment, a tank-test with DUSAUV is carried out in the ocean engineering basin in KORDI. The experimental results are also compared with the simulation results to investigate the accordance of the numerical and the real mode.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.890-896
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• 2021

Purpose: The called Aero System is important to find the well detected place in the livingroom or bedroom so, it needs to the confirmation through the Fire Dynamics Simulation Method: A fire simulation of a residential space of 59 m² was performed, and in order to find the point where the fire environment was exposed quickly, measuring points were installed at 0.6 m and 1.5 m in height for each bedroom and living room, and the point where the fire was quickly detected was confirmed. Result: It was confirmed that the temperature and carbon monoxide sensor set at a point of 1.5 m was quickly detected at the reference value. Conclusion: The Fire detection would be relatively quick if the product in which the fire extinguishing module and the AQI module were separated was installed on the wall.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.9
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• pp.1-8
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• 2007

In this paper, the new beamforming is proposed for an orthogonal frequency division multiplexing(OFDM) system with multi-input multi-output(MIMO). Through the proposed Pre-FFT beamforming technique for MIMO-OFDM, the multibeams are formed toward each multi-transmitter antenna of the desired user. The proposed beamforming for MIMO-OFDM can reduce cochannel interference and get diversity gain in the multi-user environment. Therefore, the performance of MIMO-OFDM system is very improved. BER performance improvement of the proposed approach is investigated through computer simulation by applying it to MIMO-OFDM system in the multi-user environment.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.1
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• pp.67-76
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• 2003

Recently consideration of health and interest on bio aerosols have been growing steadily. In this study, inertial impactor, which can be used to collect airborne particles and bio aerosols, was newly devised for real-time observation on the particles collected on impaction plate. and named Visual Impactor. Flow field and particle trajectory in the space between nozzle and impaction plate was analyzed numerically, and the collection effciencies were calculated. Calibration and performance evaluation of the Visual Impactor was conducted with polydisperse aerosols generated from 0.1％ sodium chloride solution. Cut-off diameter from numerical simulation was in good agreement with that from experimental results. Because of particle bounce and particle deposition on nozzle tip due to short jet-to-plate distance, the collection efficiencies from numerical and experimental analyses were different slightly. Visual Impactor was used to collect airborne particles, and the features of collected particles could be seen in real-time. Airborne particles in different weather conditions (fine, cloudy, and rainy) were sampled and compared one another The features of collected airborne particles were dependent strongly upon relative humidity. In addition, with hours elapsing, shapes and colors of collected particles were changed by evaporation and surface tension, etc.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.2
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• pp.118-130
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• 2015

Fine dust containing iron compounds is of current interests in metro subway as well as large scale industries including iron manufacturing and smelting works. This work attempts to find a new design of magnetic filter module for iron dust capture. It simulated the vertical rectangular duct with metal mesh which might promote electric fields in the duct space. A lab test using coal fly ash composed of 8.66% Fe with the most form of $Fe_3O_4$ and $Fe_2O_3$ showed capability of magnetic collection. It showed the capture efficiency with 80~93% for $PM_{2.5}$ depending on magnetic intensity. Ferromagnetic wire mesh contributed up to 50% of collection increment.

• KIEAE Journal
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• v.13 no.6
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• pp.93-98
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• 2013

The purpose of this study is to analyze the rate of opening windows that makes residents of a flat-type apartment feel pleasant in summer time. A few conditions were simulated on the wind flow that pass through internal and external spaces of the flat-type apartment, utilizing CFX program. The simulation was made with the criteria for the rates of opening window at 20%, 50%, 70% and 100%. When the rate of window opening was more 50%, the wind speed(more than 1m/s) that makes the residents feel pleasant was observed in more 60% of the internal space. When the all windows of the apartments were opened, the heat island phenomenon was almost disappeared and the pleasant wind flow was more evenly distributed in the external spaces. If residents of apartments recognize the result of this study and practice in agrement on opening windows in summer, it is expected to contribute to minimizing the energy consumption for air conditioning.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.1
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• pp.83-89
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• 2000

Antenna arrays at base-stations can be used to transmit and receive information selectively in space by reducing the interference effects. In this paper, a new model of locally scattered signals in the vicinity of mobiles is proposed, and under this model the weights of the beamformer are obtained. Computer simulation results demonstrate that the proposed scheme shows an excellent performance and works well even in the urban environment where there exist many multipath propagations with wide angular spread.

• Journal of the Korean housing association
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• v.17 no.3
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• pp.111-121
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• 2006

The objective of the study is to derive the quantitative result and method from the solar simulation on the traditional architectonic control methods and their effects for the sunshine on Ddeuljip in Northern Area of Kyongsang-Bukdo Province, Korea. The Ddeuljip(rectangular-shaped housing plan having an inner court) has distinctive form to introduce plentiful sunshine deep inside to the house in spite of disadvantageous condition resulted from the structure of traditional housing composition, that is, Ickrang(linkage block connecting buildings). From the research on the Ddeuljip, following results were derived: First, in the plan the sunshine environment was improved by placing the master bedroom on the right diagonally, or projecting it toward the Ickrang when there isn't enough space for the inner court and the Daechung(wooden floored main hall). Second in the elevation specific sunshine control methods were developed by increasing the height of the master bedroom, reducing the eaves of south elevation, or differentiating the height of ceiling structure gradually.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.33-36
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• 1999

The KOMPSAT, which is scheduled to be launched by Taurus launch vehicle in late November of 1999, will be in a sun-synchronous orbit with an altitude of 685km, eccentricity of 0.001, inclination of 98deg and local time of ascending node of 10:50 a.m. Electronics and Telecommunications Research Institute and Daewoo Heavy Industry had jointly developed a KOMPSAT Simulator as a component of the KOMPSAT Mission Control Element. The MCE had been delivered to Korea Aerospace Research Institute for the KOMPSAT ground operation. It is being used for training of KOMPSAT ground station personnel. Each of satellite subsystems and space environment were mathematically modeled in the simulator. To verify the overall function of KOMPSAT simulator, a Launch and Early Orbit Phase(LEOP) operation simulations have been performed. The simulator had been verified through various tests such as functional level test, subsystem test, interface test, system test, and acceptance test. In this paper, simulation results for LEOP operations to verify flight software adapted into simulator, satellite subsystem models and environment models are presented.

• Journal of the Korea Furniture Society
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• v.27 no.2
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• pp.128-136
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• 2016

Digital designs that appear in the three-dimensional virtual space by the digital type are designed as there is not an image created with an organic artificially generated (Creation) and representation (Modifying), developed by the specific environment given. The advanced digital design will produce a result with an algorithm according to a mathematical operation and the environment and has the nature of generating the real world, changes, development and affinity (Genetic Process). The digital design process is largely defined by a set of processes that are consistently designed to integrate form of creation, reproduction, proceeds in three steps, while the manufacture and assembly as a form of maintenance as possible the intended form of control data from the concept of building. By Joris Laarman 3D printer design is a simulation created by the digital process by the various algorithms and design achieved through the development of 3D printers, such as new materials and MX3D. From the mold production of a complex whole by using a robot and other digital production tool extracts a variety of forms.