• Journal of information and communication convergence engineering
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• v.1 no.2
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• pp.74-81
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• 2003

There are many researches on visual languages, but the most of them are difficult to support various collaborative interactions on a distributed multimedia environment. So, this paper suggests a collaborative visual language for interaction between multi-users. The visual language can describe a conceptual model for collaborative interactions between multi-users. Using the visual language, generated visual sentences consist of object icons and interaction operators. An object icon represents a user who is responsible for a collaborative activity, has dynamic attributes of a user, and supports flexible interaction between multi-users. An interaction operator represents an interactive relation between multi-users and supports various collaborative interactions. Merits of the visual language are as follows: supporting of both asynchronous interaction and synchronous interaction, supporting flexible interaction between multi-users according to participation or leave of users, supporting a user oriented modeling, etc. For example, an application to a workflow system for document approval is illustrated. So we could be found that the visual language shows a collaborative interaction.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1667-1673
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• 2015

The vibration and noise caused by the dynamic interaction between electromagnetic suspension and the linear synchronous motor stator beneath a flexible guideway remain problems in designing attractive Maglev trains. One possible method to reduce the sources of vibration is to minimize the detent force in the linear synchronous motor that creates variations in both lift force and thrust. This paper proposes lowering detent force by using separated core instead of single united core. The magnet is designed to adapt to the deflected guideway at a speed of 550km/h. This study will analyze the electromagnetic field and control performance, and how they relate to lift forces and dynamic responses.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.494-500
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• 2001

This paper presents the shape optimization to minimize the BEMF(Back Electro-Motive Force) harmonics of PM type synchronous generators. RSM(Response Surface Methodology) is well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. In this paper, RSM is used to find the optimal solution. The 2D-Finite Element Method is used to obtain the observer data of the BEMF and SQP(Sequential Quadratic Problem method) is used to solve the constrained nonlinear optimization problem.

• Journal of Power Electronics
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• v.14 no.4
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• pp.687-694
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• 2014

This paper focuses on the analysis and compensation of thrust ripples in permanent magnet linear synchronous motors (PMLSM). The main drawback in PMLSMs is the presence of thrust ripples, which are mainly due to the interaction between the permanent magnets and armature slotted core. These thrust ripples reduce the performance of the drive system in high precision applications especially at low speeds. This paper analyzes thrust ripples using the discrete wavelet transform. These undesired thrust ripples are compensated by using an adaptive feed forward controller. It is observed that this novel controller reduces about 65 percent of the thrust ripples. An extensive simulation is performed through MATLAB and it is validated through experimental results using a d-SPACE system with a DS1104 control board.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.467-471
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• 2003

The large synchronous motor for the pumped-storage plant(or SFC : Static Frequency Converter) has to be brought up to 100$\%$ rated speed and synchronized with the AC power network. Starting the motor from rest is achieved by switching current into the stator winding so that interaction between this stator current and the rotor flux will cause the correct direction of torque to be developed so that the motor turns in the required direction. Starting ranges of the synchronous motor are divided into three regions. The first region Is at standstill, the second that is called by the forced commutation is from standstill to 5-8$\%$ of rated speed, and the third, which is called by the natural commutation, is from 5-8$\%$ of rated speed to 100$\%$ rated speed. So this paper describes three regions of the control techniques of the pumped-storage synchronous motor drive.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.119-125
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• 2016

This study examined the running dynamic characteristics of a hybrid type wheel-rail high speed train, in which the propulsion method of maglev is applied. A wheel-rail high speed train propelled by a superconducting linear synchronous motor (SC-LSM) is expected to be superior to a maglev train regarding economical and interoperable aspects, still having powerful thrust force as maglev. In this paper, regarding the two methods of applying the SC-LSM to an existing wheel-rail train, to investigate the influences of SC-LSM propulsion on the dynamic characteristics of wheel-rail high speed train, the dynamic model of train including interaction between the rotor and stator of SC-LSM is established. Through the simulation using the model, the influence of the interaction between the rotor and stator of SC-LSM on stability, ride comfort and the effect of guideway irregularity are investigated.

• Wind and Structures
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• v.27 no.4
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• pp.223-234
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• 2018

In this study, a simplified three-dimensional calculation model is developed for the dynamic analysis of soil-pile group-supertall building systems excited by wind loads using the substructure method. Wind loads acting on a 300-m building in different wind directions and terrain conditions are obtained from synchronous pressure measurements conducted in a wind tunnel. The effects of soil-structure interaction (SSI) on the first natural frequency, wind-induced static displacement, root mean square (RMS) of displacement, and RMS of acceleration at the top of supertall buildings are analyzed. The findings demonstrate that with decreasing soil shear wave velocity, the first natural frequency decreases and the static displacement, RMS of displacement and RMS of acceleration increase. In addition, as soil material damping decreases, the RMS of displacement and the RMS of acceleration increase.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.153-156
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• 2000

In this paper, a mathematical model of a permanent-magnet synchronous motor (PMSM) is derived, and the steady-state characteristics of this system, when subject to constant input voltages and constant external torque, are formulated. It is shown that the PMSM model can exhibit a variety of chaotic phenomena, under some choices of system parameters and external inputs. Based on TS fuzzy modeling methodology, the TS fuzzy model of the PMSM chaotic system is presented, so the interaction between fuzzy system and chaos can be explored, and then fuzzy-model-based control methodologies can be used to control chaos in chaotic systems. Computer simulations show that the strange attractors in the derived TS fuzzy system and original chaotic system are topologically equivalent.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.11
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• pp.582-588
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• 2006

This paper presents the characteristics analysis and normal force minimization of a synchronous permanent magnet planar motor(SPMPM) with Halbach magnet way. Firstly, the flux density distribution is calculated by analytical method; then, the characteristics of this SPMPM are evaluated, some experiments have been done to verify the analysis propriety and to investigate the interaction among the characteristics; At last, the normal force is minimized by using genetic algorithm and it is decreased from 672.83[N] to 144.24[N] remarkably.

• English Language & Literature Teaching
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• v.12 no.2
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• pp.1-18
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• 2006

This study investigates the types of interactional modifications employed by Japanese and Korean university students during text-based chats. In particular, this study focuses on the role of a network-based medium on the use of interactional modifications, which have been claimed to facilitate interlanguage development. The results show that students use a variety of features of interactional modifications. The most used strategies were the use of paralinguistic features, framing, overt indication of understanding/agreement, and clarification checks, which reveals inconsistent results with findings from research on the negotiation of meaning in face-to-face interaction. Results suggest that the computer-mediated communication (CMC) environment requires the above mentioned strategies and students are able to adapt to this new context by employing alternative strategies. The majority of negotiations were generated by content and lexical items either to resolve communication problems or to better manage interactions, and very few negotiations occurred in terms of grammar. The findings suggest that text-based synchronous chats can be an effective tool for promoting interactive competence, but their effectiveness on grammatical development is uncertain.