• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.1150-1152
• /
• 1993

$TiO_2-Nb_2O_5$ thin films are fabricated by Sol-Gel method and their electrical properties have been investigated. The crystalline form is amorphous under $400^{\circ}C$ and is anatase over $500^{\circ}C$. The surface conductivity of films is higher that of $500^{\circ}C$ than that of $600^{\circ}C$.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.1
• /
• pp.25-32
• /
• 2019

Recent high-end treadmills are demanding stable performance at lower speeds. In this study, a slip control-based induction motor sensorless algorithm for treadmills, which have heavy load variations, is proposed. A modified Gopinath flux estimator is used to evaluate the rotor flux. Results indicate that a good speed regulation performance is achieved even at a low speed of approximately 3 Hz with a nominal exercise load of 90 kg body weight. The slip calculation method in the stationary coordinate system is adopted to improve the control stability. The proposed algorithm is verified throughout the simulation study using PSIM, and the experimental test consists of a commercial treadmill system.

• Korean Journal of Optics and Photonics
• /
• v.17 no.3
• /
• pp.223-230
• /
• 2006

We demonstrate a distributed fiber sensor system based on spatially-selective Brillouin scattering, using a single laser diode as a light source whose optical frequency is directly modulated by the injection current. The pump and the counter-propagating probe lights, which are sinusoidally frequency-modulated, are superposed in the fiber so that stimulated Brillouin scattering takes places only at a specific location along the fiber. Brillouin gain peak position is controlled by varying the modulation frequency. Distributions of Brillouin shift frequency are measured for the case of concatenated optical fibers of two different kinds and also for the case of temperature distribution. The temperature coefficient of the Brillouin shift frequency is measured to be $1.33MHz/^{\circ}C$.

• The Journal of the Acoustical Society of Korea
• /
• v.36 no.3
• /
• pp.158-164
• /
• 2017

Typical hydrophones in line array sensors for early detection of covert underwater targets can measure only sound-pressure-magnitude with the limitation of being unable to identify the direction of an incoming wave. In this study, a thickness shear mode vibrator was proposed as the main component of an inertia type vector hydrophone to measure both magnitude and direction of acoustic signals from targets. The equation to analyze the output voltage of the vibrator to an external force was derived, and the validity of the equation was verified through finite element analysis of a PMN-PT single crystal vibrator. The analysis results from this study will be utilized in the future for the design of inertia type vector hydrophones made of thickness shear vibrators.

• Journal of Korea Game Society
• /
• v.18 no.3
• /
• pp.71-78
• /
• 2018

Screen-based games often go to many places to install. In this case, there may be a change in the sensor or a difficulty in installation due to a difference in space configuration. Also, it is meaningful to experience the same thing as a real game, but there are cases where it is necessary to control the degree of difficulty to make it feel more fun. In this paper In the process of developing a screen archery game, which is a sensible game similar to screen golf, we will introduce a technique that facilitates installation according to changes in space. And we will explain how to control game difficulty automatically according to user's skill. And we will show you the results of the experiment.

• Journal of the Institute of Convergence Signal Processing
• /
• v.20 no.2
• /
• pp.99-104
• /
• 2019

Recently, modern people are increasing the incidence of various musculoskeletal diseases due to wrong posture. Prevention is possible through proper posture habit, but it is not easy to recognize posture by oneself. Various studies have been conducted to monitor persistent posture in daily life, but most studies using constrained measurement methods and high-cost measurement equipment are not suitable for daily life. In this paper, we implemented a posture discrimination system using a FSR sensor array that can induce posture correction spontaneously through sitting posture monitoring in daily life. The implemented system is designed as a cushion type so it is easy to apply to existing chair. In addition, it can identify five most common postures in everyday life, and can monitor real-time through Android-based smart-phone monitoring application. For the performance evaluation of the implemented system, each posture was measured 50 times repeatedly. As a result, 97.6% accuracy was confirmed.

• The Journal of the Korea Contents Association
• /
• v.8 no.11
• /
• pp.162-170
• /
• 2008

The promotion of new product is one of most important object for exhibition design. The majority of conventional exhibition technique has been implemented through one-way communication. However, using digital technology, development of new exhibition techniques is necessary for promotion of high-tech products and consideration of the phases of the times. This paper propose the various possibilities of exhibition design model which is using camera sensing and video input/output. Interactivity is efficient method to communicate between viewers and displays. Viewers can be participate actively and exhibition goal will be accomplish through this. Using camera as visual senses, video input/output technique is offered not only introducing new product but also entertaining viewers through various ways of representation. Physical experience and learning process can be expected from the exhibition space and the object. The classification of the artist who are using video input/output technique and exhibition examples are described. The collaboration on a work with the new media artist and the exhibition design will be complement each other. It will be solved the problems of realization and corporation of idea and technology.

• Journal of Advanced Navigation Technology
• /
• v.17 no.3
• /
• pp.332-345
• /
• 2013

In this paper, recently, it is described to the piezoelectric transformer technology develops, because it was have to favorable characteristics such as electromagnetic-noise free, compact size, higher efficiency, and superior power density, flux linkage, noiseless, etc. its resonance frequency was used to output waveform of a sine wave. A rotor speed identification method of induction motor based on the theory of flux model reference adaptive system(FMRAS). The estimator execute the rotor speed identification so that the vector control of the induction motor may be achieved. The improved auxiliary variable of the model are introduced to perform accurate rotor speed estimation. The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM techniuqe and DC-DC converter. High speed calculation and processing for vector control is carried out by digital signal one chip microprocessor. Validity of the proposed control method is verified through simulation and experimental results.

• Journal of Korean Society of Transportation
• /
• v.25 no.6
• /
• pp.197-208
• /
• 2007

Enormously sized buildings are appearing world-wide with the advancement of construction techniques. Large-scaled and complicated structures will have increased difficulties for dealing with safety, and will demand well-matched safety measures. This research introduced up-to-date techniques and systems which are applied in buildings in foreign nations. Furthermore, it proposed s direct guidance plan for buildings in case of fire. Since it is possible to install wireless sensor networks which detect fires or effects of fire, the plan makes use of this information. Accordingly, the authors completed a direct guidance plan that was based on omnidirectional guidance lights. It is possible to select a route with concern about both time and capacity with a concept of a non-dominated path. Finally, case studies showed that quickest path algorithms were effective for guiding efficient dispersion routes and in case of restriction of certain links in preferred paths due to temperature and smoke, it was possible to avoid relevant links and to restrict demand in the network application. Consequently, the algorithms were able to maximize safety and minimize evacuation time, which were the purposes of this study.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.5
• /
• pp.163-181
• /
• 2023

Improving the detection performance of facilities corresponding to the sensors of autonomous vehicles helps driving safety. In the road and transportation field, research is being conducted to improve the detection performance of sensors by road infrastructure or facilities. As part of this on the development of autonomous driving support infrastructure, the shape of traffic cones and drums to ensure sufficient LiDAR detection performance even rainy conditions and maintain the line-of-sight guidance function in construction zones improvement effect. The principle was to increase reflection performance and ensure no significant difference in shape from existing facilities. Traffic cones were manufactured in square pyramid shapes instead of cones, and drums were manufactured in hexagonal and octagonal pillar shapes instead of cylinders. LiDAR detection data for the facility was confirmed on a clear day and with 20 mm/h and 40 mm/h rainfall. The detection performance of the square pyramid-shaped traffic cone and octagonal column-shaped drum was to the existing facility. On the other hand, deviations occurred due to repeated measurements, and significance could not be confirmed through statistical analysis. By reflecting these results, future studies will seek a form in which data can be obtained uniformly despite the diversity of measurement environments.