• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1684-1688
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• 2003

In this paper, position and speed control algorithm of LSM (Linear Stepping Motor) using general-purpose PCI I/O board is discussed. The main purpose of this paper is to show that LSM controller can be established on the non real time operating system such as Microsoft Win2000 under the assumption that thread priority strategy is well designed. We can guarantee sampling interval less than 5msec based on the Pentium III microprocessor. Therefore this kind of LSM controller development environment makes shorten the prior research period needed to verify the validness of the proposed control strategy. We also introduce the tool of the real-time windows target system of matlab, which also makes shorten the prior research period. The main focus of this paper is on developing general purpose NT device driver which can drive the general purpose PCI board and applying it for implementing the hardware interface for 2- axis linear stepping motor control. From the experimental results show that the developed LSM controller guarantee 2 micrometer resolution in position control with 10cm/sec moving speed

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.154-156
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• 1999

A Linear Stepping Motor(LSM) can operate open loop control mode similarly to a rotary stepping motor. The linear motion without any mechanical linkage in the LSM results in several advantages for precise positioning actuators. However, to realize the more stable and higher speed control without hunting, it is necessary to derive an equivalent circuit to explain the steady-state and transisent characteristics in order to find an adequate control rule for high performance control of the LSM. In this paper, magnetic equivalent circuit is obtained, based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. The 1-step response characteristic of the LSM is analyzed by the ACSL with the voltage equations, the force equations, the force equations and the kinetic equation.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.84-92
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• 2001

(La,Sr)MnO$_3$(LSM)-YSZ 복합체 양극의 산소환원 반응기구에 대해 고찰하였다. YSZ를 첨가함에 따라 복합체 양극의 ohmic 저항이 증가하고, 분극 저항은 YSZ를 40 wt%~50 wt% 혼합하였을 때 최소값을 나타내었다. 또한 LSM-YSZ 복합체 양극의 산소환원 반응기구는 1가 산소이온의 표면확산과 산소이온전달반응에 의해서 지배됨을 알 수 있었다. 임피던스 분석 결과에 따르면 고주파수 영역에서 나타나는 반원은 산소이온전달반응으로 산소분압 의존성이 거의 없고, YSZ가 40 wt% 첨가되었을 때 최소값을 나타내었다. 중간주파수 영역에서 나타나는 반원은 1가 산소이온의 표면확산반응으로 산소분압 의존성은 약 1/4이고, YSZ가 40~50 wt% 첨가되었을 때 최소값을 나타냈다. 한편, 저주파수 영역에 나타나는 반원은 가스확산반응으로 산소분압 의존성이 1이고, 온도에 따른 의존성이 거의 없었다.

• Structural Engineering and Mechanics
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• v.87 no.3
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• pp.243-254
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• 2023

Engineering structures usually suffer from cracks. The crack geometry has an influence on the structural mechanical properties and subsequent crack propagations. However, as an extensively utilized method in fracture analysis, the extended finite element method provided by Abaqus fails to output the specific location and dimensions of fractures. In this study, a technique to capture the crack geometry is proposed. The technique is based on the invariant level set method (I-LSM), which can avoid updating the level set function during crack development. The solution is achieved by an open-source plug-in programmed by Python. Three examples were performed to verify the effectiveness and robustness of the program. The result shows that the developed program can accurately output the crack geometry in both the 2D and 3D models. The open-source plug-in codes are included as supplementary material.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.87-93
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• 2015

The uneven reaction surface profile facing the lift magnets in attractive Maglev vehicles naturally brings about pitch motion of the bogie. In particular, in the placement configuration of the long stator of the linear synchronous motor (LSM) on the track for high-speed propulsion, surface irregularities and the offsets between the stator packs create measurable airgaps, i.e., the clearance between the magnet and the stator, with discontinuously extreme values, resulting in bogie pitch motion. This occurs because the airgap velocities and accelerations derived by the differentiations of the measured air-gaps are used to determine the voltages applied to the magnets. This paper incorporates bogie pitch motion into a control law for each magnet controller to reduce the variations in both the airgap and the pitch angle. The effectiveness of the proposed method is analyzed using a full-scale Maglev vehicle running over a test track.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.118-120
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• 1997

A Lineal Stepping Motor (LSM) can operate in an open loop control mode similarly to a rotary stepping motor. However, the LSM has a large transient vibration, and it sometimes causes the miss-step. In this paper, a new vibration suppression method using an energy stored in winding inductance and induced voltage of the LPM is proposed.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.4
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• pp.337-342
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• 1995

Two feeding trials were conducted to determine the effect of molasses feeding on the growth performances of bulls. In the first experiment, the straw of a control diet of straw and urea was replaced by molasses of 150 g ($M_{150}$) or $300g{\cdot}kg^{-1}$ ($M_{300}$). The three diets were fed ad libitum to three groups of bulls having five in each and the dietary responses were statistically analyzed in a simple design. The bulls were given fishmeal ($30g{\cdot}hd^{-1}{\cdot}d^{-1}$), wheat bran (0.5% of Liveweight, LW) and allowed grazing for $5hrs{\cdot}d^{-1}$. Molasses supplementation significantly (p < 0.001) increased the dry matter intake (DMI) of the bulls of $M_{150}$ (35.8g) and of $M_{300}$ (42.9g) than the control ($30.4g{\cdot}kg^{-0.75}$). The daily LW gain of the bulls of the $M_{150}$ (982g) was significantly (p < 0.05) higher than the bulls of the control or of the $M_{300}$ diet. In the second experiment, a control group of four bulls was fed a straw diet. Treatment two groups, having four bulls in each, were fed a mixed diet of Leucaena leucocephala and Setaria splendida(1:1, DM basis) with (LSM) and without (LS) molasses at $100g{\cdot}kg^{-1}$. The dietary responses were statistically analyzed in a simple design. The bulls of the LSM diet had significantly (p < 0.05) higher DMI, DM digestibility and LW gain ($128g{\cdot}kg^{-0.75}$, $663g{\cdot}kg^{-1}$ and $419g{\cdot}d^{-1}$, respectively) than the bulls of the LS diet ($98.3g{\cdot}kg^{-0.75}$, $583g{\cdot}kg^{-1}$ and $292g{\cdot}d^{-1}$, respectively). But the differences between the LSM and the control were nonsignificant. It may be concluded that molasses may be utilized as supplement to straw at $150g{\cdot}kg^{-1}$ or forages at $100g{\cdot}kg^{-1}$ diet for the profitable beef production from young growing bulls.

• Wind and Structures
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• v.27 no.3
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• pp.199-211
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• 2018

This paper deals with wind fragility and risk analysis of high rise buildings subjected to stochastic wind load. Conventionally, such problems are dealt in full Monte Carlo Simulation framework, which requires extensive computational time. Thus, to make the procedure computationally efficient, application of metamodelling technique in fragility analysis is explored in the present study. Since, accuracy by the conventional Least Squares Method (LSM) based metamodelling is often challenged, an efficient Moving Least Squares Method based adaptive metamodelling technique is proposed for wind fragility analysis. In doing so, artificial time history of wind load is generated by three wind field models: i.e., a simple one based on alongwind component of wind speed; a more detailed one considering coherence and wind directionality effect, and a third one considering nonstationary effect of mean wind. The results show that the proposed approach is more accurate than the conventional LSM based metamodelling approach when compared to full simulation approach as reference. At the same time, the proposed approach drastically reduces computational time in comparison to the full simulation approach. The results by the three wind field models are compared. The importance of non-linear structural analysis in fragility evaluation has been also demonstrated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.18-25
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• 1998

G $d_{0.2}$C $e_{0.8}$ $O_{1.9}$(CGO) for electrolyte and L $a_{0.5}$S $r_{0.5}$Mn $O_3$(LSM50) for cathode in Solid Oxide Fuel Cells(SOFC) were synthesized by citrate process. Specimens were prepared with sintering temperatures at 110$0^{\circ}C$, 120$0^{\circ}C$ and 130$0^{\circ}C$, which were fabricated by slurry coating with citric acid contents. Interfacial resistance was measured between cathode and electrolyte using AC-impedance analyzer. With various citric acid content, the degree of agglomeration for the initial particles changed. Also sintering temperature changed the particle size and the degree of densification of cathode. Factors affecting the interfacial resistance were adherent degree of the electrolyte and cathode, distribution of TPB(three phase boundaries, TPB i.e., electrolyte/electrode/gas phase area) and porosity of cathode. By increasing the sintering temperature, particle size and densification of the cathode were increased. And then, TPB area which occurs catalytic reaction was reduced and so interfacial resistance was increased.sed.sed.d.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.47-54
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• 2022

In this paper, MEMS embedded system design implemented the sensor events via analyzing the characteristics that dynamically happened to an abnormal status in power IoT environments in order to guarantee a maintainable operation. We used three kinds of tools in this paper, at first Bluetooth Low Energy (BLE) technology which is a suitable protocol that provides a low data rate, low power consumption, and low-cost sensor applications. Secondly LSM6DSOX, a system-in-module containing a 3-axis digital accelerometer and gyroscope with low-power features for optimal motion. Thirdly BM1422AGMV Digital Magnetometer IC, a 3-axis magnetic sensor with an I2C interface and a magnetic measurable range of ±120 uT, which incorporates magneto-impedance elements to detect the magnetic field when the current flowed in the power devices. The proposed MEMS system was developed based on an nRF5340 System on Chip (SoC), previously compared to the standalone embedded system without bluetooth technology via mobile App. And also, MEMS embedded system with BLE 5.0 technology broadcasted the MEMS system status to Android mobile server. The experiment results enhanced the performance of MEMS system design by combination of sensors, BLE technology and mobile application.