• Title/Summary/Keyword: Time-Domain Analysis

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A Study on Dynamic Analysis of Moored Ship Motions by Tsunami (쓰나미에 의한 계류 선박의 동적 동요 해석에 관한 연구)

  • Cho Ik-Soon
    • Journal of Navigation and Port Research
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    • v.29 no.8 s.104
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    • pp.661-666
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    • 2005
  • Recent warnings indicate that there is a potential risk of massive earthquake. These earthquakes could produce large-scale tsunamis. Consideration of the effect of Tsunami to the moored ship is very important bemuse it brings the loss of life and vast property damage in a viewpoint of ship operations within a harbor. If a tsunami occurs, a ship in a harbor may begin drifting in case of ship entering and departing harbor, and breakage of mooring rope and drifting of moored ship are happened. And extremely serious accident, such as stranding and collision to a quay, might occur. On the other hand, since the tsunami consists of approximately component waves of several minutes, there is a possibility of resonance with the long period motion of mooring vessel. As the speed of Tsunami is much faster than tidal current in a harbor, a strong resisting force might act on the moored ships. In this paper, the numerical simulation procedure in the matter of ship motions due to the attack of large-scale tsunamis are investigated and the effects on the ship motions and mooring loads are evaluated by numerical simulation.

Expansion of Test Frequency Band and Improvements of Field Uniformity in a Reverberation Chamber by Using Dual-Band Diffusers (이중 대역 확산기를 이용한 전자파 잔향실 시험 주파수 대역 확장 및 전자기장 균일도 향상에 관한 연구)

  • Lim Wook-Chae;Rhee Joong-Geun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.1 s.104
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    • pp.74-80
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    • 2006
  • This paper presents the characteristics of electromagnetic field uniformity in a reverberation chamber that can be used alternatively for the analysis, test and evaluation of electromagnetic interference and immunity. The dual-band diffuser, which can be used at two different frequency bands in a reverberation chamber, is applied, and it is made of two different single-band Schroeder's Quadratic Residue Diffusers. The FDTD method is used to analyze the field characteristics. Compared with single-band diffuser, the dual-band diffuser shows the improvement in not only expansion of test frequency band but also in characteristics of the field uniformity, polarity, power efficiency, and tolerance. Therefore, the reverberation chamber with the dual-band diffuser is a better facility, for the analysis and measurement of electromagnetic interference and immunity, than the reverberation chamber with a single-band diffuser.

Classification of Consonants by SOM and LVQ (SOM과 LVQ에 의한 자음의 분류)

  • Lee, Chai-Bong;Lee, Chang-Young
    • The Journal of the Korea institute of electronic communication sciences
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    • v.6 no.1
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    • pp.34-42
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    • 2011
  • In an effort to the practical realization of phonetic typewriter, we concentrate on the classification of consonants in this paper. Since many of consonants do not show periodic behavior in time domain and thus the validity for Fourier analysis of them are not convincing, vector quantization (VQ) via LBG clustering is first performed to check if the feature vectors of MFCC and LPCC are ever meaningful for consonants. Experimental results of VQ showed that it's not easy to draw a clear-cut conclusion as to the validity of Fourier analysis for consonants. For classification purpose, two kinds of neural networks are employed in our study: self organizing map (SOM) and learning vector quantization (LVQ). Results from SOM revealed that some pairs of phonemes are not resolved. Though LVQ is free from this difficulty inherently, the classification accuracy was found to be low. This suggests that, as long as consonant classification by LVQ is concerned, other types of feature vectors than MFCC should be deployed in parallel. However, the combination of MFCC/LVQ was not found to be inferior to the classification of phonemes by language-moded based approach. In all of our work, LPCC worked worse than MFCC.

Prediction of Hydraulic Performance of a Scaled-Down Model of SMART Reactor Coolant Pump (스마트 원자로냉각재펌프의 축소모형에 대한 수력성능 예측)

  • Kwon, Sun-Guk;Park, Jin-Seok;Yu, Je-Yong;Lee, Won-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.8
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    • pp.1059-1065
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    • 2010
  • An analysis was conducted to predict the hydraulic performance of a reactor coolant pump (RCP) of SMART at the off-design as well as design points. In order to reduce the analysis time efficiently, a single passage containing an impeller and a diffuser was considered as the computational domain. A stage scheme was used to perform a circumferential averaging of the flux on the impeller-diffuser interface. The pressure difference between the inlet and outlet of the pump was determined and was used to compute the head, efficiency, and break horse power (BHP) of a scaled-down model under conditions of steady-state incompressible flow. The predicted curves of the hydraulic performance of an RCP were similar to the typical characteristic curves of a conventional mixed-flow pump. The complex internal fluid flow of a pump, including the internal recirculation loss due to reverse flow, was observed at a low flow rate.

The Seismic Behavior of Corrugated Steel Plate Lining in Cut-and-Cover Tunnel (개착식 터널에서 파형강판 라이닝의 동적 거동 특성)

  • Kim Jung-Ho;Kim Nag-Young;Lee Yong-Jun;Lee Seung-Ho;Chung Hyung-Sik
    • 한국터널공학회:학술대회논문집
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    • 2005.04a
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    • pp.233-247
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    • 2005
  • Most tunnel lining material which has been used in the domestic is a concrete. But many problems as the construction period, the cost, and the crack occurrence for the design, construction, and management were happened in the concrete lining. For this reason, many research institutes like the Korea Highway Corporation recognize the necessity of an alternate material development and grow on the interest for that. So in this study, the seismic behaviour characteristics for the application of the Corrugated Steel Plate Lining in cut-and-cover tunnel are evaluated as several conditions for the backfill height, the cutting slope, and the relative density of backfill soil are changed. The compressive stress which is calculated in the Corrugated Steel Plate Lining by the seismic load is decreased as the backfill height increases and the cut slope grows gentle. Also, the moment shows the tendency of decrease according to the increase of the backfill height. But in the case of the relative density of the backfill soil is small, the moment increases according to the increase of the backfill height and affects the dynamic behaviour characteristic. So it is considered that the relative density of the backfill soil is also the important point. As the result in analyzing the seismic response characteristics of the reinforcement spacing of the Corrugated Steel Plate, the variation in the compressive force is hardly happened, but the moment and the shear force increase on the reinforcement spacing being narrow.

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Identification of Cisplatin-Resistance Associated Genes through Proteomic Analysis of Human Ovarian Cancer Cells and a Cisplatin-resistant Subline

  • Zhou, Jing;Wei, Yue-Hua;Liao, Mei-Yan;Xiong, Yan;Li, Jie-Lan;Cai, Hong-Bing
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.12
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    • pp.6435-6439
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    • 2012
  • Chemoresistance to cancer therapy is a major obstacle to the effective treatment of human cancers with cisplatin (DDP), but the mechanisms of cisplatin-resistance are not clear. In this study, we established a cisplatin-resistant human ovarian cancer cell line (COC1/DDP) and identified differentially expressed proteins related to cisplatin resistance. The proteomic expression profiles in COC1 before and after DDP treatment were examined using 2-dimensional electrophoresis technology. Differentially expressed proteins were identified using matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and high performance liquid chromatography-electrospray tandem MS (NanoUPLC-ESI-MS/MS). 5 protein spots, for cytokeratin 9, keratin 1, deoxyuridine triphosphatase (dUTPase), aarF domain containing kinase 4 (ADCK 4) and cofilin1, were identified to be significantly changed in COC1/DDP compared with its parental cells. The expression of these five proteins was further validated by quantitative PCR and Western blotting, confirming the results of proteomic analysis. Further research on these proteins may help to identify novel resistant biomarkers or reveal the mechanism of cisplatin-resistance in human ovarian cancers.

Design of Matching Layers for high Efficiency-wide band Ultrasonic Transducers (고출력 광대역 초음파 탐촉자를 위한 정합층 설계)

  • Kim, Yeon-Bo;Roh, Yong-Ae
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.5
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    • pp.82-89
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    • 1996
  • Application fields of ultrasonic transducers can be divided into two categories, a high ultrasonic resolution required field and a high ultrasonic power required field. This paper is aimed to determine the optimal properties of the matching layers of the transducer for each of the applications. Further, it is aimed to optimize the properties of the matching layers that show satisfactory performances for both of the application fields. Through the direct time domain analysis of the transmission and reflection behavior of the ultrasonic wave, apart from the conventional equivalent circuit analysis, and Fourier transformation of its results, we found the optimum acoustic impedances of the matching layers. The newly determined layers provide much better transducer performance-57% at most-than those obtained with conventional design methods. Based on the results, we also found the optimal acoustic impedances of the layers good for both of the application fields. For te optimization, we developed a new transducer performance evaluation parameter that can be applied to any type of ultrasonic transducers.

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Designs and Performance Analysis of Adaptive Transmission Scheme for Vehicle Communication System (차량 통신 시스템을 위한 적응적 전송 기법 설계 및 성능 분석)

  • Moon, Sangmi;Chu, Myeonghun;Lee, Jihye;Kwon, Soonho;Kim, Hanjong;Kim, Cheolsung;Hwang, Intae
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.9
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    • pp.3-11
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    • 2016
  • Vehicle to Everything (V2X) communication has been growing to enhance traffic safety by employing advanced wireless communication systems. V2X communication is one core solution for governing and advancing future traffic safety and mobility. In this paper, we design the system level simulator (SLS) of Long Term Evolution (LTE)-based V2X and propose the adaptive transmission scheme for vehicle communication. The proposed scheme allocates the resource randomly in time and frequency domain, and transmit the message according to probability of transmission. The performance analysis is based on freeway case in periodic message transmission. Simulation results show that proposed scheme can improve the cumulative distribution function (CDF) of packet reception ratio (PRR) and average PRR.

Dynamic Response for Critical Velocity Effect Depending on Supporting Stiffness of High-Speed Railway Trackbed (고속철도 노반지지조건에 따른 임계속도효과의 동적응답)

  • Lee, Il-Wha
    • Journal of the Korean Geotechnical Society
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    • v.29 no.1
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    • pp.5-12
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    • 2013
  • The critical velocity effect on railway trackbed means the amplification of vibration energy when the train running-speed and group velocity of ground surface wave are superimposed. It is called a pseudo-resonance phenomenon of time domain. In the past, it was not issued because the train speed was low and the ground group velocity was higher. But since the high-speed train is introduced, critical velocity reported causing a track irregularity. So far, theoretical analysis has been performed because of the complexity of formation process. However it requires reasonable consideration which is similar to actual track and trackbed conditions. In the present paper, finite element analysis to verify the critical velocity effect is performed considering each track structure and trackbed supporting stiffness. As a result, the deformation amplification caused by the critical velocity effect is verified to analyze each supporting stiffness and track system.

Characterisation and Clinical Significance of FLT3-ITD and non-ITD in Acute Myeloid Leukaemia Patients in Kelantan, Northeast Peninsular Malaysia

  • Yunus, Noraini Mat;Johan, Muhammad Farid;Al-Jamal, Hamid Ali Nagi;Husin, Azlan;Hussein, Abdul Rahim;Hassan, Rosline
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.12
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    • pp.4869-4872
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    • 2015
  • Background: Mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor gene may promote proliferation via activation of multiple signaling pathways. FLT3-internal tandem duplication (FLT3-ITD) is the most common gene alteration found in patients diagnosed with acute myeloid leukaemia (AML) and has been associated with poor prognosis. Materials and Methods: We performed mutational analysis of exons 14-15 and 20 of the FLT3 gene in 54 AML patients using PCR-CSGE (conformational sensitive gel electrophoresis) followed by sequencing analysis to characterise FLT3 mutations in adult patients diagnosed with AML at Hospital USM, Kelantan, Northeast Peninsular Malaysia. Results: FLT3 exon 14-15 mutations were identified in 7 of 54 patients (13%) whereas no mutation was found in FLT3 exon 20. Six ITDs and one non-ITD mutation were found in exon 14 of the juxtamembrane (JM) domain of FLT3. FLT3-ITD mutations were associated with a significantly higher blast percentage (p-value = 0.008) and white blood cell count (p-value = 0.023) but there was no significant difference in median overall survival time for FLT3-ITD+/FLT3-ITD- within 2 years (p-value = 0.374). Conclusions: The incidence of FLT3-ITD in AML patients in this particular region of Malaysia is low compared to the Western world and has a significant association with WBC and blast percentage.