• Title/Summary/Keyword: segmental structure

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Performance Comparison of Conventional and Segmental Rotor Type Switched Reluctance Motor

  • Jeong, Kwang-Il;Xu, Zhenyao;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1138-1146
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    • 2018
  • Performance comparisons of switched reluctance motor for cooling fan application are dealt in this paper. Conventional and novel segmental type motors with the same dimension are compared. The conventional 12/8 type is very popular and used widely. The structure of segmental rotor type motor is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. This type of motor has short flux path and no flux reversal in the stator. The auxiliary poles are not wound by the windings and only provide the flux return path. Compared with conventional SRM, the segmental structure increases electrical utilization of the machine and decreases core losses, which leads to higher efficiency. To verify the segmental structure, finite element method (FEM) is employed to get static and dynamic characteristics of both SRMs. Finally, the prototypes of conventional and segmental SRMs are tested for characteristics comparisons.

Study on the Seismic Behavior of Precast Concrete Segmental Bridge Piers with Shear Resistance Connecting Structure (전단저항 연결체를 갖는 프리캐스트 세그먼트 교각의 지진거동에 관한 연구)

  • Kim, Tae-Hoon;Kim, Young-Jin;Kim, Seong-Woon;Kim, Chul-Young;Shin, Hyun-Mock
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.85-88
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    • 2008
  • The purpose of this study was to investigate the seismic behavior of precast concrete segmental bridge piers with shear resistance connecting structure. A model of precast concrete segmental bridge columns with shear resistance connecting structure was tested under a constant axial load and a cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. The proposed numerical method for the seismic behavior of precast concrete segmental bridge piers with shear resistance connecting structure is verified by comparison with reliable experimental results.

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Design and Characteristics Analysis of Segmental Rotor Type 12/8 poles SRM with single teeth windings (단일치 권선을 가지는 분절회전자형 12/8SRM의 설계 및 특성해석)

  • Jeong, Guang-Il;Lee, Dong-Hee;Ahn, Jin-Woo
    • Proceedings of the KIPE Conference
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    • 2014.11a
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    • pp.39-40
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    • 2014
  • In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed. Different from conventional structures, the proposed rotor consists of a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure short flux paths are taken and no flux reverse exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. Compared with conventional 12/8 SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to high efficiency. To verify the proposed structure, finite element method (FEM) is employed to get static and dynamic characteristics. Finally, a prototype of the proposed motor is tested for characteristics comparisons.

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Performance Assessment of Precast Concrete Segmental Bridge Columns with Shear Resistance Connecting Structure (전단저항 연결체를 갖는 프리캐스트 세그먼트 교각의 성능평가)

  • Kim, Tae-Hoon;Kim, Young-Jin;Kim, Seong-Woon;Shin, Hyun-Mock
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.4A
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    • pp.591-601
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    • 2008
  • The purpose of this study was to investigate the performance of precast concrete segmental bridge columns with shear resistance connecting structure. The system can reduce work at a construction site and makes construction periods shorter. A model of precast concrete segmental bridge columns with shear resistance connecting structure was tested under a constant axial load and a cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. An bonded or unbonded tendon element based on the finite element method, that can represent the interaction between tendon and concrete of prestressed concrete member, is used. A joint element is newly modified to predict the inelastic behaviors of segmental joints. The proposed numerical method gives a realistic prediction of performance throughout the loading cycles for several test specimens investigated.

Design and Analysis of a Segmental Rotor Type 12/8 Switched Reluctance Motor

  • Zhang, Hongtao;Lee, Dong-Hee;Lee, Chee-Woo;Ahn, Jin-Woo
    • Journal of Power Electronics
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    • v.14 no.5
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    • pp.866-873
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    • 2014
  • In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed for cooling fan applications. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure, short flux paths are taken and no flux reversion exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. When compared with the conventional SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get the static and dynamic characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

Seismic Design of Soil-Reinforced Segmental Retaining Walls (블록식 보강토 옹벽의 내진설계)

  • 유충식
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.11c
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    • pp.69-83
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    • 1999
  • Soil-reinforced segmental retaining walls(SRW) have been proven to be high earthquake-resistant structure during recent earthquakes in United States and Japan. The mechanicals behavior of the SRWs under seismic loading, however, has not been fully understood. Although the seismic design issues for the civil engineering structures have gained much attention in Korea due to the increase in frequency of earthquake occurrence, the seismic design for the SRWs has not been being implemented. This study has been undertaken with the aim of developing a more rational seismic design/analysis method for soil-reinforced segmental retaining walls. This paper present fundamentals of current seismic design/analysis method and the results of a comparative study between NCMA and FHWA design guidelines, Practical implications of the findings from this study are discussed in great detail.

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An Implementation of the Baseline Recognizer Using the Segmental K-means Algorithm for the Noisy Speech Recognition Using the Aurora DB (Aurora DB를 이용한 잡음 음성 인식실험을 위한 Segmental K-means 훈련 방식의 기반인식기의 구현)

  • Kim Hee-Keun;Chung Young-Joo
    • MALSORI
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    • no.57
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    • pp.113-122
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    • 2006
  • Recently, many studies have been done for speech recognition in noisy environments. Particularly, the Aurora DB has been built as the common database for comparing the various feature extraction schemes. However, in general, the recognition models as well as the features have to be modified for effective noisy speech recognition. As the structure of the HTK is very complex, it is not easy to modify, the recognition engine. In this paper, we implemented a baseline recognizer based on the segmental K-means algorithm whose performance is comparable to the HTK in spite of the simplicity in its implementation.

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Ortho-phonic Alphabet Creation by the Musical Theory and its Segmental Algorithm (악리론으로 본 정음창제와 정음소 분절 알고리즘)

  • Chin, Yong-Ohk;Ahn, Cheong-Keung
    • Speech Sciences
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    • v.8 no.2
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    • pp.49-59
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    • 2001
  • The phoneme segmentation is a very difficult problem in speech sound processing because it has found out segmental algorithm in many kinds of allophone and coarticulation's trees. Thus system configuration for the speech recognition and voice retrieval processing has a complex system structure. To solve it, we discuss a possibility of new segmental algorithm, which is called the minus a thirds one or plus in tripartitioning(삼분손익) of twelve temporament(12 율려), first proposed by Prof. T. S. Han. It is close to oriental and western musical theory. He also has suggested a 3 consonant and 3 vowel phonemes in Hunminjungum(훈민정음) invented by the King Sejong in the 15th century. In this paper, we suggest to newly name it as ortho-phonic phoneme(OPP/정음소), which carries the meaning of 'the absoluteness and independency'. OPP also is acceptable to any other languages, for example IPA. Lastly we know that this algorithm is constantly applicable to the global language and is very useful to construct a voice recognition and retrieval structuring engineering.

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A Case Study on Design of Geosynthetic-Reinforced Segmental Retaining Walls (다단식 보강토 옹벽 설계사례에 관한 고찰)

  • Park, Si-Sam;Cho, Sam-Deok;Park, Du-Hee;Chang, Ki-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.168-175
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    • 2008
  • The method of reinforced earth walls has grown remarkably and the frequency of utilization has been increased on a national scale thereafter introduced in the middle 1980s in Korea. Furthermore the construction case of the extensive Geosynthetic-Reinforced Segmental Retaining Walls had been increased. Currently, the design criterion of FHWA and NCMA mainly used in Korea suggest determining the horizontal distance of the upper/lower retaining wall based on the study results of the internal stability and the external stability of Segmental Retaining Walls but in many cases are not suitable for the actual situation in Korea. Therefore, in this study reviewed the design criterion of Geosynthetic-Reinforced Segmental Retaining Walls, performed the internal and external stability in Paju, Gyeonggi-do based on the design criterion of FHWA and NCMA, suggested the modified design criterion of FHWA with analyzing the results, and performed the stability analysis for the internal and external stability and the compound failure. Moreover for the confirmation of the modified FHWA design standard, the suggestion and the analysis of the numerical analysis approaching method using shear strength reduction technique were performed and the design cases utilized the modified FHWA design standard based on the study analysis were introduced.

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Study on the Performance of New Shear Resistance Connecting Structure of Precast Member (프리캐스트 부재의 새로운 전단저항 연결체의 성능에 관한 연구)

  • Kim, Tae-Hoon;Jin, Byeong-Moo;Kim, Young-Jin;Kim, Seong-Woon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1A
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    • pp.147-154
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    • 2008
  • The purpose of this study is to critically evaluate the structural performance of an innovative new shear resistance connecting structure of precast member. Joints such as shear resistance connecting structure require special attention when designing and constructing precast segmental structures. An experimental and analytical study was conducted to quantify performance measures and examine one aspect of detailing for developed shear resistance connecting structure. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. A joint element is used to predict the inelastic behavior of the joints between segmental members. Future work by the authors will do a model test of precast segmental prestressed concrete bridge columns with this shear resistance connecting structure, and examined both the structural behavior and seismic performance.