• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.369-370
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• 2009

This study aims to find an optimum mix proportions for high-performance shotcrete using industrial by-product from power plants. Compressive strengths of various mix proportions with varying amount of fly ash were verified if they meet the required limits.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2167-2169
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• 2004

The main concern for a displacement measurement is the performance of a sensor such as speed, resolution, accuracy and so on. The mainly used sensors are a linear CCD(charge coupled device) and a PSD(position sensitive detection) as a non-contact type. The output value of a linear CCD is so sensitive to a temperature change that it needs a cooling device. Additionally, because of its structural problem, there are some limits in resolution and speed, and it needs a complex image processing algorithm. Also, PSD has some disadvantages like sensitivity to environmental lights and nonlinearities. Like this, a linear CCD and PSD have their own characteristics and if we know them well, we can choose the one of the two sensors properly in some applications according to purposes. In this paper, I performed which one is superior to the other among the two sensors in terms of accuracy, resolution, measurement speed, signal to noise ratio.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.56.4-56
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• 2001

Using GPS in the navigation systems such as aviation, maritime and land applications, integrity is considered importantly with accuracy for safety. Integrity monitoring performed in the GPS receiver itself is Receiver Autonomous Integrity Monitoring (RAIM) and need not an independent ground monitoring station. RAIM algorithm uses redundant information when more than four satellites are visible and makes consistency checks between measurement information to alarm users whether the system is operating out of its specified performance limits. Selective Availability (SA) that was used to protect the security interests of the U.S. and its allies by globally denying the full accuracy of the civil system was turned off on May 1, 2000 ...

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.166-173
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• 1999

Reference models are used in many control algorithms for improvement of transient response characteristics. They provide desired trajectories that the plant should follow Most control systems have bounded control inputs to avoid saturation of the plant. If we design the reference models that do not account for limits of the control inputs, control performance of the system may be deteriorated. In this paper a new approach of avoiding saturation by varying the reference model for TDC(time delay control) based systems subject to step changes in the reference input. In this scheme, the variable reference model is determined based on the information on control inputs and the size of the step changes in the reference inputs. This scheme was verified by application to the BLDC motor position control system in simulations and experiments. The responses of the TDC with the variable reference model showed better tracking performance than that with the fixed reference model.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.544-549
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• 2001

The effect of power supply voltage on the performance limits in a laboratory Magneto-rheological fluid based device was identified by experiments. It suggests that the frequency range of motion for control be limited by the voltage attenuation due to the coil inductance and the maximum power supply voltage set for practical use of MRF devices. In this work, the magnetic and electrical characteristics of MRF device are investigated and a design procedure is formulated to achieve the desired performance for a given power supply.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.163-171
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• 2020

There are many differences in narrative delivery between common movies and Virtual Reality(VR) films due to their differences in the appreciation structure. In VR films, scene changes by cuts have hindered the immersion of the audience instead of promoting narrative delivery. There are a range of experiments on narratives and immersion to solve this issue in VR films. Floating Tent applies hand gestures and immersive effects found in game elements and does not disturb narrative delivery by setting proper spaces and employing a direction technique to enable the melting of narratives into the characteristics of the spaces. There are time limits to offsound and mission performance, and devices fit for apocalyptic spatial expressions are made through a program. One of measures for the increasingly growing interactive storytelling in VR films is effective immersion. In narrative delivery, it is important to consider spatial setting and immersion to enable active intervention into events for immersion rather than passive audience only supposed to watch characters' acting.

• Journal of Aerospace System Engineering
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• v.14 no.2
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• pp.12-19
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• 2020

In Korea, the regulation is MOLIT Notice 2018-290, Guidance for Approval of Synthetic Flight Trainer as Flight Simulator and Flight Training Device. The FAA (Federal Aviation Administration) categorizes FSTD (Flight Simulation Training Device) into FFS (Full Flight Simulator) and FTD (Flight Training Device), according to its level. Additional categories for regulation are airplane and helicopter, depending on the type of aircraft. In this study, the objective tests for the handling quality of the FAA and Korean regulations were compared and analyzed. In QPS (Qualification Performance Standard), related test titles, flight conditions, and tolerance limits were analyzed for the handling quality. Based on this study, recommendations on amendments to the regulation was presented.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.596-601
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• 2011

Autonomous navigating algorithms for mobile robots have been proved to be a difficult task. Based on the excellent homing performance shown by many insects, bio-inspired navigation algorithms for robotic experiments have been widely researched and applied to the design of navigational strategies for mobile robots. In this paper, among them, we analyze two simple landmark navigation methods their strengths and limits. We investigate the effect of the occlusion problem mainly, which is an important yet tough problem in many landmark navigation algorithms. In the point of view of the error of homing vector and the performance of the homing paths in the environment with artificial occlusions, we investigate the effect of occlusion problem in both methods in order to further study on solutions.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.3
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• pp.17-23
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• 2016

A test unit for Organic Rankine Cycle (ORC) power generation system was developed and experimentally reviewed the performance of the ORC system. Two different organic fluids (R-245fa & Novec 649) were tested as working fluids for the system. System behavior was measured and analyzed along with the variables, such as temperature, pressure, rpm and shaft power. It is one of the findings that Novec 649 fluid is to be less pressurized than R-245fa in order to up to the heat source (boiler) capacity, that limits the experiment as high as 2 kW in shaft power.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.266-274
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• 2008

The need for more fuel-efficient and lower-emission vehicles has driven the technical development of alternative fuels such as Liquefied Petroleum Gas(LPG) which is able to meet the limits of better emission levels without many modifications to current engine design. LPG has a high vapor pressure and lower viscosity and surface tension than diesel and gasoline fuels. These different fuel characteristics make it difficult to apply it for the conventional gasoline or diesel fuel pump directly. In this study, experiments are performed to get performance and efficiency of the fuel pump at different condition as temperature, rotating speeds, composition of fuel. The characteristics of fuel pump is affected by cavitation due to the variation of temperature and composition.