• Journal of the Korean Mathematical Society
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• v.50 no.6
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• pp.1271-1290
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• 2013

Let M be a fixed left R-module. For a left R-module X, we introduce the notion of M-prime (resp. M-semiprime) submodule of X such that in the case M=R, it coincides with prime (resp. semiprime) submodule of X. Other concepts encountered in the general theory are M-$m$-system sets, M-$n$-system sets, M-prime radical and M-Baer's lower nilradical of modules. Relationships between these concepts and basic properties are established. In particular, we identify certain submodules of M, called "primeM-ideals", that play a role analogous to that of prime (two-sided) ideals in the ring R. Using this definition, we show that if M satisfies condition H (defined later) and $Hom_R(M,X){\neq}0$ for all modules X in the category ${\sigma}[M]$, then there is a one-to-one correspondence between isomorphism classes of indecomposable M-injective modules in ${\sigma}[M]$ and prime M-ideals of M. Also, we investigate the prime M-ideals, M-prime submodules and M-prime radical of Artinian modules.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.129-135
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• 2012

There are many ways in which electric vehicles are mathematically modeled and simulated. The components have different physical background and models, but have to fit into one mathematical model. A multiphysics model structure is required. Depending on the goal of the simulation, there are various levels on which the simulation can be performed. This is called multilevel, consisting of a conceptual system level, a circuit level and a more detailed component level. This paper discusses which multiphysics models and multilevel simulations are required for the various components in an electric vehicle. Also, this simulation approach could improve the effectiveness of learning in engineering education.

• The Plant Pathology Journal
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• v.18 no.5
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• pp.284-287
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• 2002

The antifungal activity of super reductive water (SRW) against plant pathogenic fungi was examined to extend its application to integrated pest management (IPM) for plant diseases. Diluted solutions ($\times$1/10, $\times$1/25, and $\times$1/50) of SRW inhibited fungal growth of kiwifruit soft rot pathogen, Diaporthe actinidiae, in a concentration dependent manner, When kiwifruits were inoculated on wounds with mycelium blocks, stock and diluted solutions successfully inhibited the disease development. In addition to the high pH of the SRW, fungistatic activity was also considered as the cause of the antifungal effect against the pathogen. Whereas conidial germination of Magnaporthe grisea was not affected by the diluted SRW solutions, appressorium formation was significantly inhibited in a concentration dependent manner, With little harmfulness to human health and environment SRW could be used to control plant pathogenic fungi, particularly appressorium-forming fungal pathogens.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.541-543
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• 1998

Generally, PI control is simple and easy to implement and gains of PI control are determined by specifying a dynamics of the servo driver system. However, the gain-tuning is so difficult that it is relied on an expert's effort. This paper presents a gain auto-tuning method for PI controllers based on a fuzzy inference mechanism. First, the proposed fuzzy inference system identifies a system moment of inertia and adjusts control gains by using the difference in speed responses between a real plant and a reference model. Second, this paper proposes an improved fuzzy PI controller. To reduce the speed overshoot, we adapt a control method that selects a proper PI gains with respect to the load inertia variation. To prove the validity of the proposed gain tuning algorithm and the feasibility of the servo drive, a high performance servo drive will be implemented by DSP(TMS320C31) and intelligent power module (IPM). The proposed controller is applied to the speed control of the 300W AC servo motor. Some simulations and experimental results show that the proposed fuzzy PI controller is more robust than the conventional PI controller against the load inertia variation.

• JOURNAL OF ELECTRICAL WORLD
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• s.280
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• pp.64-70
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• 2000

파워디바이스는 산업$\cdot$전력$\cdot$교통$\cdot$정보 등 여러 분야에서 사용되고 그 기기들의 성능은 이 파워디바이스의 성능에 의해 크게 좌우된다. 특히 고도 정보화시대가 되는 21세기에는 전력수요가 점점 더 증가될 것이기 때문에 인버터화 등에 의한 생에너지 대책과 클린에너지 등에 의한 신에너지의 창출이 중요한 과제가 되고 있다. 한편, 지구환경 보호면에서 전기자동차 등의 환경고려형 장치의 보급이 활발해질 것이 예상된다. 이와 같은 사회환경 속에서 파워 일렉트로닉스를 지탱하는 소자로서 파워디바이스는 점점 더 그 역할의 중요성이 커지고 있다. 최근의 파워디바이스로서는 디스크리트, 모듈, IPM(Intelligent Power Module)등 여러 가지의 디바이스가 출현하고 있는데 그 성능을 결정하는 중심이 되는 것이 파워디바이스 칩이다. 파워디바이스 칩 자신도 급속히 진화하여 현재는 MOS계 파워디바이스 칩이 주류를 이루고 있다. 그 중에서도 사용하기 쉽다는 면에서 MOSFET와 IGBT(Insulated Gate Bipolar Transistor)가 주로 실용화되고 있으며, 미세가공기술과 라이프타임 제어기술의 진전에 따라 현저한 성능개선이 진행되고 있다. 한편, 공업용 대용량인버터나 전력응용에서 요구되는 고내압$\cdot$대용량 영역에서는 당분간 저손실이라는 의미에서 바이폴라계의 사이리스터형 디바이스가 주류로 사용되고, 이 영역에서는 GTO에 대체하는 소자로서 GCT(Gate Commutated Turn-off)사이리스터가 개발되어 그 응용이 확대될 것이 기대되고 있다. 또한 전압형 인버터장치에서는 IGBT와 GCT등의 스위칭디바이스와 함께 환류용 다이오드(FWD)가 필요하며 이 FWD의 특징 개선도 스위칭디바이스의 개선과 병행하여 추진되고 있다.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.25-33
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• 2015

This paper presents the d-q axis equivalent circuit model of an interior permanent magnet (IPM) which includes the iron loss resistance. The model is implemented to be able to run in real-time on the FPGA-based HIL simulator. Power electronic devices are removed from the motor control unit (MCU) and a separated controller is interfaced with the real-time simulated motor drive through a set of proper inputs and outputs. The inputs signals of the HIL simulation are the gate driver signals generated from the controller, and the outputs are the winding currents and resolver signals. This paper especially presents iron loss prediction which is introduced by means of comparing the torque calculated from d-q axis currents and the desired torque; and minimizing the torque difference. This prediction method has stable prediction algorithm to reduce torque difference at specific speed and load. Simulation results demonstrate the feasibility and effectiveness of the proposed methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.232-234
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• 2017

In this research, the BLDC motor 2 axis controller was designed using a dual core processor. The controller used TMS320F28377D which is TI's latest dual-core DSP, and the BLDC motor was selected with the position of resolver having high reliavility and the speed sensor built-in type motor.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.347-349
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• 1995

This paper describes current controlled PWM technique of IPM synchronous motors for a wide variety of speed control applications. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the IPMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. This paper proposes a new field-weakening control algorithm using phase current feedback to improve the torque characteristics and to reduce the torque ripple of IPMSM in the constant power region. The improved torque characteristics of speed control strategy with current feedback control algorithm is analyzed and the performance is investigated by the computer simulation results.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1587-1596
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• 2016

This paper presents an interactive locomotion controller using motion capture data and inverted pendulum model. Most of the data-driven character controller using motion capture data have two kinds of limitation. First, it needs many example motion capture data to generate realistic motion. Second, it is difficult to make natural-looking motion when characters navigate dynamic terrain. In this paper, we present a technique that uses dimension reduction technique to motion capture data together with the Gaussian process dynamical model (GPDM), and interpolates the low-dimensional data to make final motion. With the low-dimensional data, we can make realistic walking motion with few example motion capture data. In addition, we apply the inverted pendulum model (IPM) to calculate the root trajectory considering the real-time user input upon the dynamic terrain. Our method can be used in game, virtual training, and many real-time applications.

• Journal of Magnetics
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• v.21 no.4
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• pp.561-569
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• 2016

Although pretty methods have been proposed to reduce torque ripple, they generally suffer from the decreased torque density. This paper will investigate the spoke-type interior permanent magnet (IPM) machine with shaping methods, including the sinusoidal (SIN), the inverse cosine (ICS), the sinusoidal with third harmonic (SIN+3rd), and the inverse cosine with third harmonic (ICS+3rd). In order to obtain low torque ripple and high torque density, the shaping method applied in rotor and stator at the same time, termed as the dual-shaping method, is proposed. This method is analytically derived and further confirmed by finite element method (FEM). It turns out that the ICS and ICS+3rd shaping methods are more suitable for outer rotors, while the SIN and the SIN+3rd shaping method should be used in inner stators. The original machine, the singular shaped machines and the dual-shaped machines on electromagnetic performances are compared for evaluation. The results verify that the dual-shaping method can improve torque density, whilst reducing torque ripple.