• Journal of Power Electronics
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• 제14권5호
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• pp.937-945
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• 2014

This paper presents an optimized space vector pulse-width modulation (OSVPWM) technique for a five-level cascaded H-bridge (CHB) inverter. The space vector diagram of the five-level CHB inverter is optimized by resolving it into inner and outer two-level space vector hexagons. Unlike conventional space vector topology, the proposed technique significantly reduces the involved computational time and efforts without compromising the performance of the five-level CHB inverter. A further optimized (FOSVPWM) technique is also presented in this paper, which significantly reduces the complexity and computational efforts. The developed techniques are verified through MATLAB/SIMULINK. Results are compared with sinusoidal pulse-width modulation (SPWM) to prove the validity of the proposed technique. The proposed simulation system is realized by using an XC3S400 field-programmable gate array from Xilinx, Inc. The experiment results are then presented for verification.

• Journal of Magnetics
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• 제20권1호
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• pp.62-68
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• 2015

This paper presents an experimental technique to accurately separate a permanent magnetic field and an induced one from the total magnetic fields generated by a steel ship, through compensating for the Earth's magnetic field. To achieve this, an Earth's magnetic field simulator was constructed at a non-magnetic laboratory, and the field separation technique was developed, which consisted of five stages. The proposed method was tested with a scaled model ship, and its permanent and induced magnetic fields were successfully extracted from the magnetic field created by the ship. Finally, based on the separated permanent magnetic field data, the permanent magnetization distribution on the hull was predicted by solving an inverse problem. Accordingly, the permanent magnetic fields generated by the ship can easily be calculated at any depth of water.

• Journal of Power Electronics
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• 제14권1호
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• pp.115-124
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• 2014

This paper presents the implementation of two-arm modulation (TAM) technique for the independent control of a two-induction motor drive fed by a five-leg inverter (FLI). A carrier-based space vector pulse width modulation technique for TAM is proposed to generate switching signals for FLI. Two independent three-phase space vector modulators are utilized to control two motors. The motor drive system applies two separate indirect field-oriented control methods. The stationary voltage outputs from the vector control are synthesized in the three-phase space vector modulator to generate switching signals for FLI. The performance of the independent control of the motors and the voltage utilization factor are likewise analyzed. Simulation and experimental results verify the effectiveness of the proposed method for the independent control of the two-motor drive system. The proposed technique is successfully validated by dSPACE DS1103 experimental work.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.86-95
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• 2020

There is a unique method of musical expression in the nature documentary. The expression method is Mickey Mousing technique, which expresses the movement of animals with music. The Mickey mousing technique can also be used in other types of documentaries, but it is most prominently used in nature documentaries. The Mickey Mousing technique cannot be used in any field other than music composition, because the composer should describe the movement of animals by playing music to match the animal's movements exactly. It is also because they have to play the instrument separately according to the sound source. In this study, we examined the nature documentaries broadcast by KBS over the last five years and analyzed the cases of Mickey Mousing technique. Therefore, we obtained research results that the Mickey Mousing technique is necessary and that the music composition is also necessary as a background music of nature documentaries.

• 대한기계학회논문집A
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• 제20권3호
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• pp.933-944
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• 1996

In this paper, two new techniques, the pattern filling and the refined flow field regeneration, based on the finite element method and Eulerian mesh advancement approach have been developed to analyze incompressible viscous flow with free surfaces. The gorerning equation for flow analysis is Navier-Stokes equation including inertia and gravity effects. The penalty and Newton-Raphson methods are used effectively for finite element formulation. The flow front surface and the volume inflow rate are calculated using the pattern filling technique to select an adequate pattern among five filling patterns at each quadrilateral control volume. By the refined flow field regeneration technique, the new flow field which renders better prediction in flow surface shape is generated and the velocity field at the flow front part is calculated more exactly. Using the new thchniques to be developed, the dam-breaking problem has been analyzed to predict flow phenomenon of fluid and the predicted front positions versus time have been compared with the reported experimental result.

• Radiation Oncology Journal
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• 제9권1호
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• pp.165-170
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• 1991

유방암의 근치적 또는 수술후 방사선 조사시 치료해야 할 부위는 유방과 주위임파 조직으로 매우 복잡한 3차인적 구조이다. 여러 방향의 조사에 의한 조사부위의 중복을 피하고 부작용을 최소화하기위한 여러 방법이 시도돼 왔으나 계산과정이나 치료방법이 매우 복잡하여 여러가지 문제점이 있었다. 이에 저자들은 Asymmetric jaw를 이용하고 gantry, collimator와 couch를 적절히 회전시켜 조사야가 만나는 부분에서 beam의 divergence를 없애줌으로써 가장 이상적으로 치료할 수 있는 방법을 소개하고자 한다. 5문 조사 방법은 다음과 같은 장점을 가진다. 1. 모든 조사야의 set up이 같은 위치에서 시행되므로 환자의 위치변동에 의한 target volume의 변화를 막을수 있다. 2. Half beam block을 사용하지 않아도 된다. 3. 조사야가 만나는 선(match line)에서 beam의 divergence가 없으므로 정확하다. 4. 계산이 쉽고 환자 set up이 용이하다. 5. 매일 치료를 같은 방법으로 정화하게 반복할 수 있다.

• International Journal of Advanced Culture Technology
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• 제4권2호
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• pp.1-6
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• 2016

Impervious surfaces are important indicators for urban development monitoring. Accurate mapping of urban impervious surfaces with observational satellites, such as VNREDSat-1, remains challenging due to the spectral diversity not captured by an individual PAN image. In this article, five multi-resolution image fusion techniques were compared for the task of classifting urban impervious surfaces. The result shows that for VNREDSat-1 dataset, UNB and Wavelet tranformation methods are the best techniques in reserving spatial and spectral information of original MS image, respectively. However, the UNB technique gives the best results when it comes to impervious surface classification, especially in the case of shadow areas included in non-impervious surface group.

• 상하수도학회지
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• 제20권6호
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• pp.789-797
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• 2006

This study was conducted to establish the refined model for prediction of flocculation/sedimentation efficiency in factual drinking water treatment plants using model tree technique. In order to carry out machine leaning for determining each linear model, five parameters; time, coagulant dose, raw water turbidity, SCD and conductivity, which were measured and collected from the field (K_DWTP), were selected and used. The existing analytical models developed by previous researchers were used only to examine closely the mechanism of flocculation rather than to apply it for practical purpose. The refined model established using model tree technique in this study could predict the factual sedimentation efficiency accurately (below 9% of average absolute error). Also, in aspect of engineering convenience, without any additional manipulation of parameters, it can be applied to practical works.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.1047-1057
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• 2016

Design engineering process for field programmable gate array (FPGA)-based reactor trip functions are developed in this work. The process discussed in this work is based on the systems engineering approach. The overall design process is effectively implemented by combining with design and implementation processes. It transforms its overall development process from traditional V-model to Y-model. This approach gives the benefit of concurrent engineering of design work with software implementation. As a result, it reduces development time and effort. The design engineering process consisted of five activities, which are performed and discussed: needs/systems analysis; requirement analysis; functional analysis; design synthesis; and design verification and validation. Those activities are used to develop FPGA-based reactor bistable trip functions that trigger reactor trip when the process input value exceeds the setpoint. To implement design synthesis effectively, a model-based design technique is implied. The finite-state machine with data path structural modeling technique together with very high speed integrated circuit hardware description language and the Aldec Active-HDL tool are used to design, model, and verify the reactor bistable trip functions for nuclear power plants.

• 공학교육연구
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• 제19권6호
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• pp.32-37
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• 2016

The purpose of this study is to extract a skill level of human resource in the field of science and technology. To accomplish the goal of this study, precedent research was conducted and then, the draft of skill level for Human Resource in the field of Science and Technology (HRST) was created by wrap-up meeting. The skill level of the HRST was finalized after confirming verification of 20 SMEs (Subject Matter Experts) from January to February 2016 by two times. The conclusions are as follows; First, the skill level of the HRST consists five categories. Each of the level has educational background, work experience, certification, duty, major and so on. Second, the contents of the skill level were found to be mostly valid.