• Journal of Institute of Control, Robotics and Systems
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• v.12 no.8
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• pp.798-804
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• 2006

To overcome the limited relative uncertainty and work range of the existing planar stage and the bulk structure of the contact-less motor for rotation, the novel operating principle to realize the precise rotation is suggested. It uses the two-axial vector forces, normal force and thrust force, of three-induction type of axial motors located $120^{\circ}$ apart, resulting in the contact-free rotation of the mover. Firstly in this paper, the magnetic forces across the air gap are modeled and simulated under the various conditions. It clarifies the feasible range of the derived solution. And the algorithm compensating the strong cross couple between the forces and the control inputs; generally AC magnitude and slip frequency, is given to realize the independent control of six axes. Finally, for the successfully implemented system, the round test and the micro step test results are given.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.391-394
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• 2000

In this paper four lossy and one lossless inductance simulator topologies employing a single DO-OTA are presented. For the topologies proposed the inductance $L_{eq}$ and the series resistance $R_{eq}$ are independently adjustable. The topologies employ a single capacitor and are canonic in the number of capacitors. The resistors in the topologies can easily be implemented also with DO-OTAs. In this case the topologies proposed change to DO-OTA-C inductor simulators which is important from the integration point of view. Simulation results are included to verify theory.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.497-502
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• 2004

This paper presents applications of the objective stress rates to stress update algorithms for transient shell dynamic analysis within the context of explicit time integration. The hypo elasto-plastic materials are assumed in establishing constitutive equations. The derivation of the objective stress rates are investigated by use of the Lie derivative. Comparison results are given between the Kirchhoff and Cauchy stress formulation. The Jacobian determination algorithm proposed in this paper is presented in association with the Belytschko-Lin-Tsay shell theory. Several numerical examples are demonstrated including contact and non-contact examples, by which proposed algorithms are compared with respect to the accuracy and effectiveness.

• Bulletin of the Society of Naval Architects of Korea
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• v.8 no.2
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• pp.1-12
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• 1971

This paper describes, firstly, on analytical method of computing the eigenvalues of vertical vibration of ships, taking into account for the distribution of hull weight including added mass and the effect of shear deflection and rotary inertia. The frequency equation is solved by Galerkins method into form of numerical integration. Applying the above described equation, model experiment of vertical vibration was carried out in order to varify the validity of the analytical method of vertical vibration. The model, which was made of acrylite plate, was ship-shaped wall-sided vessel with bulkheads, deck openings, and fore and after peak tank at both ends. The results of experiments carried out both in air and on water showed that the observed natural frequencies and the observed patterns of natural modes of vibration were in good agreement with analytically calculated values for 2,3, and 4-node vibration.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.139-142
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• 2013

A study was carried out to evaluate the solid phase micro-extraction (SPME) for formaldehyde emission analysis of uncoated plywood. In SPME, formaldehyde was on-fiber derivatized through headspace extraction and analyzed by gas chromatography coupled with mass spectrometry (GC/MS). The SPME was compared with desiccators (DC-JAS 233), small-scale chamber (SSC-ASTM D6007) and liquid-liquid extraction (LLE-EPA 556) methods which were performed in accordance with their respective standards. Compared to SSC (RSD 4.3%) and LLE (RSD 5.0%), the SPME method showed better repeatability (RSD 1.8%) and not much difference from DC (RSD 1.4%). The SPME has proven to be highly precise (at 95% confidence level) with better recovery (REC 102%). Validation of the SPME method for formaldehyde quantitative analysis was evidenced. In addition, the SPME by air sampling directly from plywood specimens (SPME-W) correlated best with DC ($r^2$ = 0.983), followed by LLE ($r^2$ = 0.950) and SSC ($r^2$ = 0.935).

• Advances in aircraft and spacecraft science
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• v.3 no.1
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• pp.77-93
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• 2016

In this paper, a zero-dimensional mathematical formulation for rapid and explosive decompression analyses of pressurized aircraft is developed. Air flows between two compartments and between the damaged compartment and external ambient are modeled by assuming an adiabatic, reversible transformation. Both supercritical and subcritical decompressions are considered, and the attention focuses on intercompartment venting systems. In particular, passive and active vents are addressed, and mathematical models of both swinging and translational blowout panels are provided. A numerical procedure based on an explicit Euler integration scheme is also discussed for multi-compartment aircraft analysis. Various numerical solutions are presented, which highlight the importance of considering the opening dynamics of blowout panels. The comparisons with the results from the literature demonstrate the validity of the proposed methodology, which can be also applied, with no lack of accuracy, to the decompression analysis of spacecraft.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.89-96
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• 2019

The purpose of this study is to investigate Nest Labs (Nest)'s business strategy. The activities based on strategic choices for monetizing connected product are investigated. Nest's capacity and functionality is to offer a seamless integration of devices, platforms, and services and the "Works with Nest" offers an ecosystem fulfilling the needs of different partners. For monetizing customer data, Nest provides a seamless customer experience supported by product incentives. Nest introduces open APIs to connect its connected products to the wider Internet of things (IoT) and open to "If This, Then That." The Nest app controls them from one single place. Nest partners with 32 energy providers as of 2017 and they provide energy from renewable and non-renewable energy sources. Nest also creates a sales channels in direct and indirect route and expands is business model to other industries such as home-rental service, 'AirBnB' to help consumers become more energy-efficient at home.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.3
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• pp.1-14
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• 2019

Cooperative systems among various unmanned vehicles are widely used in various field and emerging. Unmanned vehicles are able to operate various missions without operator onboard and they are highly stable. Collaborative work of multiple unmanned vehicles is emphasized due to the difficulty of recent missions such as SEAD (Suppression of the Enemy Air Defenses), MUSIC (Manned Unmanned Systems Integration Capability), goldentime in the rescue mission. In this study, ROS and Pixhawk were proposed as a method of construction of a collaboration system and framework for an integrated simulation environment for heterogeneous unmanned vehicles is proposed. Totally 5 unmanned vehicles were set for the simulation for the observation of illegal fishing boats. This paper shows the feasibility of the cooperative system using ROS and Pixhawk through the simulation and the experiment.

• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.13-16
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• 2010

The superconducting synchronous motor or generator mostly has high permeability iron only around outer yoke portion. Therefore, if excitation voltage (Back E.M.F) is calculated from 2 dimensional magnetic field distributions, it can be largely different from actual value due to additional voltage originated from end coils. In order to calculate the excitation voltage more accurately, 3 dimensional magnetic field calculation is necessary for including the end coil effect from large air-gap structure. The excitation voltage can be calculated by stator (armature) coil linkage flux originated from rotor (field) coil excitation, but it is difficult to calculate the flux linkage exactly because of complicated structure of the stator coil. This paper shows a method to calculate the excitation voltage from 3 dimensional magnetic energy that can be calculated directly from volume integration of magnetic flux density and field intensity scalar product through FEM (Finite Element Method) analysis software.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.1-7
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• 2023

Recently, in the semiconductor industry, memory device market is focusing on producing ultra-thin wafers for high integration. In the wafer manufacturing process, wafers after backgrinding and CMP process must be picked up as individual dies and subjected to be peeled off from the dicing tape. However, ultra-thin dies are vulnerable to the possibility of breakage and failure in their thickness and size. This research studies the mechanism of peeling a die with a high-aspect ratio using a thermopneumatic method instead of a die ejector with physical pins. Setting compressed air and the temperature as main factors, we determine the success of the digester using thermopneumatic system and analyze the good die to find the possibility of making mass-production equipment.