• Journal of Auto-vehicle Safety Association
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• v.14 no.3
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• pp.60-64
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• 2022

In the automotive industry, the development of automobiles to meet safety requirements is becoming increasingly complex. This is because quality evaluation agencies in each country are continually strengthening new safety standards for vehicles. Among these various requirements, collision safety must be satisfied by controlling airbags, seat belts, etc., and can be defined as post-crash safety. Apart from this safety system, the Advanced Driver Assistance Systems (ADAS) use advanced detection sensors, GPS, communication, and video equipment to detect the hazard and notify driver before the collision. However, research to improve passenger safety in case of an accident by using the sensor of active safety represented by ADAS in the existing passive safety is limited to the level that utilizes the sudden braking level of the FCA (Forward Collision-avoidance Assist) system. Therefore, this study aims to develop logic that can improve passenger protection in case of an accident by using ADAS information and driving information secured before a collision. The proposed logic was constructed based on LSTM deep learning techniques and trained using crash test data.

• Earthquakes and Structures
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• v.24 no.1
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• pp.21-36
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• 2023

Structural vibrations generated by earthquakes and wind loads can be controlled by varying the structural parameters such as mass, stiffness, damping ratio, and geometry and providing a certain amount of passive or active reaction forces. A Double-Tuned Mass Dampers (DTMDs) system, which is simple and more effective than the conventional single tuned mass damper (TMD) system for vibration mitigation is presented. Two TMDs tuned to the first two natural frequencies were used to control vibrations. Experimental investigations were carried out on a three degrees-of-freedom frame model to investigate the effectiveness of DTMDs systems in controlling displacements, accelerations, and base shear. Numerical models were developed and validated against the experimental results. The validation showed a good match between the experimental and numerical results. The validated model was employed to investigate the behavior of a five degrees-of-freedom shear building structure, wherein mass dampers with different mass ratios were considered. The effectiveness of the DTMDs system was investigated for harmonic, seismic, and white noise base excitations. The proposed system was capable of significantly reducing the story displacements, accelerations, and base shears at the first and second natural frequencies, as compared to conventional single TMD.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1797-1801
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• 2005

SLAM(Simultaneous localization and mapping) and AI(Artificial intelligence) have been active research areas in robotics for two decades. In particular, localization is one of the most important issues in mobile robot research. Until now expensive sensors like a laser sensor have been used for the mobile robot's localization. Currently, as the RFID reader devices like antennas and RFID tags become increasingly smaller and cheaper, the proliferation of RFID technology is advancing rapidly. So, in this paper, the smart floor using passive RFID tags is proposed and, passive RFID tags are mainly used to identify the mobile robot's location on the smart floor. We discuss a number of challenges related to this approach, such as RFID tag distribution (density and structure), typing and clustering. In the smart floor using RFID tags, because the reader just can senses whether a RFID tag is in its sensing area, the localization error occurs as much as the sensing area of the RFID reader. And, until now, there is no study to estimate the pose of mobile robot using RFID tags. So, in this paper, two algorithms are suggested to. We use the Markov localization algorithm to reduce the location(X,Y) error and the Kalman Filter algorithm to estimate the pose(q) of a mobile robot. We applied these algorithms in our experiment with our personal robot CMR-P3. And we show the possibility of our probability approach using the cheap sensors like odometers and RFID tags for the mobile robot's localization on the smart floor.

• Physical Therapy Korea
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• v.22 no.1
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• pp.30-36
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• 2015

The purpose of this study was to examine the relationships between the ankle dorsiflexion passive range of motion (DF PROM) under a non-weight bearing condition and the normalized reach distance in three directions of the Y-Balance Test (YBT). Sixty-one healthy adults (32 males and 29 females, age: $23.0{\pm}3.0$ years, height: $169.3{\pm}8.9cm$, weight: $61.9{\pm}5.4kg$) participated in this study. The ankle DF PROM was measured using a goniometer. To assess dynamic balance, all subjects performed three trials to determine the maximum lower extremity reach in the anterior, posteromedial, and posterolateral directions of the YBT. The relationship between the ankle DF PROM and both the normalized reach distance in each direction and the composite score of the YBT were analyzed using the Pearson correlation. Only the normalized reach distance in the anterior direction of the YBT was significantly related to the ankle DF PROM measured under a non-weight bearing condition (r=.50, p<.001). Neither the normalized reach distances in the posterior directions nor the composite score of the YBT were significantly correlated with the ankle DF PROM measured under a non-weight bearing condition. These findings suggest that ankle DF PROM does not affect the overall dynamic balance of the lower extremity, with only the anterior dynamic balance affected among the three directions.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.1 s.41
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• pp.61-70
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• 2005

Shaking table tests are carried out on a single-degree-of-freedom mass that is equipped with a hybrid base isolation system. The isolator consists of a set of four specially-designed friction pendulum systems (FPS) and a magnetorheological (MR) damper. The structure and its hybrid isolation system are subjected to various intensities of near- and far-fault earthquakes on a large shake table. The proposed fuzzy controller uses feedback from displacement or acceleration transducers attached to the structure to modulate resistance of the semi-active damper to motion. Results from several types of passive and semi-active control strategies are summarized and compared. The study shows that a combination of FPS isolators and an adjustable MR damper can effectively provide robust control of vibration for a large full-scale structure undergoing a wide variety of seismic loads.

• Journal of IKEEE
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• v.25 no.3
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• pp.548-555
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• 2021

This paper outlines the basic concepts, approaches and research trends of fault diagnosis and fault tolerant control applied to industrial processes, facilities, and motor drives. The main role of fault diagnosis for industrial processes is to create effective indicators to determine the defect status of the process and then take appropriate measures against failures or hazadous accidents. The technologies of fault detection and diagnosis have been developed to determine whether a process has a trend or pattern, or whether a particular process variable is functioning normally. Firstly, data-driven based and model-based techniques were described. Secondly, fault detection and diagnosis techniques for industrial processes are described. Thirdly, passive and active fault tolerant control techniques are considered. Finally, major faults occurring in AC motor drives were listed, described their characteristics and fault diagnosis and fault tolerant control techniques are outlined for this purpose.

• Steel and Composite Structures
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• v.20 no.4
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• pp.801-812
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• 2016

In an actual design, none of the structures with shear behaviors will be designed for torsional moments. Any failure or damages to roofs, infills, shear walls, and braces caused by an earthquake, will inevitably result in relocation of center of mass and rigidity of the structure. With these changes, the dynamic characteristics of structure could be changed during an earthquake at any moment. The main objective of this paper is to obtain the relationship between time-varying eccentricity of load and corner lateral displacement. In this study, various methods have been used to determine the structural response for time-varying lateral corner displacement. As will be seen below, some of the structural calculation methods result in a significant deviation from the actual results, although these methods include the interaction effects of modes. Controlling the lateral displacement of structure can be performed in different ways such as, passive dampers, friction dampers, semi-active systems including the MR damper and active Systems. Selecting and locating these control systems is very important to bring the maximum safety with minimum cost into the structure. According to this study will be show the relation between the corner lateral displacements of structure and time-varying eccentricity by different kind of methods during an earthquake. This study will show that the response of the structure at the corners due to an earthquake can be very destructive and because of changing the eccentricity of load, calculating the maximum possible response of system can be carried out by this method. Finally, some kind of systems must be used for controlling these displacements. The results shows that, the CQC, DSC and exact methods is comply each other but the results of Vanmark method is not comfortable for these kind of buildings.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.717-724
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• 2023

An essential step in evaluating and comparing the performance of two passive radiation dosimeter types, thermosluminescent (TLD) and optically stimulated luminescence (OSL), used by workers in environments with ionizing radiation for individual radiological monitoring and control of external exposure at various times (cumulative dose for 1 month), is to compare the measured dose accuracy, energy response, and coefficient of variation. In fact this performance study consists in determining the accuracy of both R(10) and R(0.07) which are considered as the ratios of the measured dose (Hp(10) or Hp(0.07)) to the delivered dose (Hp(10) or Hp(0.07)) for each photon energy. The validity of the results of this test is based on the acceptance limits of the ICRP and the international standard IEC-62387. The relative energy response used is normalized to the ¹³⁷Cs 662 keV energy to find which energy response is closest to the ideal case, and the coefficient of variation that allows to determine the statistical fluctuation of the Hp(10) and Hp(0.07) doses. The results of the accuracy test for the OSL and TLD dosimeters are acceptable because they fall within the ICRP limits. For the energy response, the OSL performs better than the TLD for Hp(10) and Hp(0.07), and for the coefficient of variation, the OSL satisfies the requirements of ISO 62387 for both Hp(10) and Hp(0.07), while the TLD satisfies these requirements only for the measurement of Hp (0.07).

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.4
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• pp.33-42
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• 2004

The usual practice of placing viscoelastic dampers (VED) in the inter-story of building structures frequently interfere with spatial planning and obstruct internal view. These shortcomings can be overcome by installing VED in seismic joints or in expansion joints which are usually hidden under a cover. This study investigates the effect of installing VED in seismic joints to reduce earthquake-induced dynamic reponses. Parametric studies were conducted using 3-DOF systems connected by VED and subjected to earthquake excitations to investigate the effectiveness of the proposed scheme. Nonlinear dynamic analyses were carried out with five-story structures composed of different structure systems and connected by seismic joints. According to the analysis results the use of VED in seismic joints turned out to be effective as long as the natural frequencies of the connected structures are different enough.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.199-208
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• 2017

Lithium polymer batteries are used in energy storage systems (ESS), electric vehicles (EVs), etc. due to their high safety, fast charging and long lifecycle, and now they are used in agricultural drones. However, when overcharging and overdischarging, the lithium-polymer battery is destroyed in the gap structure in the lithium-ion battery and the battery life is reduced. In order to prevent overcharge and overdischarge, uneven cell voltage Cell balancing system is needed. In this paper, a fuzzy controller suitable for nonlinear systems is proposed by detecting the unbalanced cells by detecting the voltage difference between charging and discharging of each cell, and suggesting the applied cell balancing algorithm. In this paper, we have designed the cell balancing of the battery pack of agricultural drones by fuzzy control and it is designed for equal control between cells. As a final result, we checked whether cell balancing is good, and when there are two cells, Cell balancing was confirmed. We tested whether it could be used for other products. As a result, we confirmed that cell balancing is good regardless of the number of cells used.