• Title/Summary/Keyword: Comparison of simulation

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Trend Comparison of Repeated Measures Data between Two Groups (반복측정 자료에서 개체기울기를 이용한 집단간의 차이 검정법)

  • Hwang, Kum-Na;Kim, Dong-Jae
    • The Korean Journal of Applied Statistics
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    • v.19 no.3
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    • pp.565-578
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    • 2006
  • Repeated measurement data between two group is often used in the field of medicine study. In this paper, we suggest a method for comparison of the trend between two groups based on repeated measurement data. First, we estimate regression coefficient of linear regression model from each subject and generate samples using the regression coefficient estimated previous. And then, we test the difference between two groups by unpaired t-test, Wilcoxon rank sum test and placement test using generated samples. Monte Carlo Simulation is adapted to examine the power and experimental significance levels of several methods in various combinations.

Phase Jitter Analysis of Overlapped Signals for All-to-All TWSTFT Operation

  • Juhyun Lee;Ju-Ik Oh;Joon Hyo Rhee;Gyeong Won Choi;Young Kyu Lee;Jong Koo Lee;Sung-hoon Yang
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.3
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    • pp.245-255
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    • 2023
  • Time comparison techniques are necessary for generating and keeping Coordinated Universal Time (UTC) and distributing standard time clocks. Global Navigation Satellite System (GNSS) Common View, GNSS All-in-View, Two-Way Satellite Time and Frequency Transfer (TWSTFT), Very Long Baseline Interferometry (VLBI), optical fiber, and Network Time Protocol (NTP) based methods have been used for time comparison. In these methods, GNSS based time comparison techniques are widely used for time synchronization in critical national infrastructures and in common areas of application such as finance, military, and wireless communication. However, GNSS-based time comparison techniques are vulnerable to jamming or interference environments and it is difficult to respond to GNSS signal disconnection according to the international situation. In response, in this paper, Code-Division Multiple Access (CDMA) based All-to-All TWSTFT operation method is proposed. A software-based simulation platform also was designed for performance analysis in multi-TWSTFT signal environments. Furthermore, code and carrier measurement jitters were calculated in multi-signal environments using the designed simulation platform. By using the technique proposed in this paper, it is anticipated that the TWSTFT-based time comparison method will be used in various fields and satisfy high-performance requirements such as those of a GNSS master station and power plant network reference station.

A Study on Turbulent Flame Propagation Model of S. I. Engines (스파크 점화기관의 난류 화염전파모델에 관한 연구)

  • 유욱재;최인용;전광민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.10
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    • pp.2787-2796
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    • 1994
  • The modeling of combustion process is an important part in an engine simulation program. In this study, calculated results using a conventional B-K model and the other model which is called GESIM were compared with experimentally measured data of a three-cylinder spark-ignition engine under wide range of operating conditions. The burn rates calculated from the combustion models were compared with the burn rate calculated from the one-zone heat release analysis that uses measured pressure data as an input data. As a result of the two models' comparison, the GESIM combustion model conformed to be closer to the data acquired from the experiment in wide operating ranges. The GESIM model has been improved by introducing a variable that considers the flame size, the area of flame conacting the piston surface into the model, based on the comparison between the experimental result and the calculated results. The improved combustion model predicts experimental results more precisely than that of GESIM combustion model.

Road Alignment Design Using GIS

  • Kang, In-Joon;Lee, Jun-Seok;Kim, Tae-Hun;Park, Hyun
    • Korean Journal of Geomatics
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    • v.1 no.1
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    • pp.15-20
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    • 2001
  • In this study, several basic data for road design and GIS data were used for selecting the optimized road alignment database system. The cut and fill volumes were compared with existing manual road design method through the analysis and data application in this database system. We solved and estimated objective, economic, environmental and technical problems caused in road construction comparing existing manual method with the road alignment which was selected in GIS automatically. Also, we performed three dimensional simulation with the existing road design program and simulation of virtual reality through Virtual GIS. This study showed the method in selecting the optimized road alignment through the analysis and comparison of the selected road alignment. The goal of this study is comparison and analysis of definite cut and fill volume and environmental problem after the road construction through analyzing and comparing the social, economic, technical and environmental aspect in the road alignments with various statistic data.

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Performance Comparison of Single-Carrier and Multi-Carrier Systems in a Terahertz Wireless Communication Environment

  • Asiedu, Derek Kwaku Pobi;Ahiadormey, Roger Kwao;Shin, Suho;Lee, Kyoung-Jae
    • Journal of Advanced Information Technology and Convergence
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    • v.9 no.1
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    • pp.11-24
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    • 2019
  • This paper investigates the performance comparison of a Terahertz (THz) communications for a single-carrier and a multi-carrier single antenna point-to-point communication system. The multi-carrier system and single carrier system consider the orthogonal frequency division multiplexing (OFDM) and the minimum mean square error linear equalizer (MMSE-LE), respectively. We compare the frame-error-rate (FER) and throughput performance of both the systems for a THz communication environment with the carrier frequency of 300GHz and the tapped delay line (TDL) channel models described in 3GPP. It is observed from the simulation results that the OFDM systems outperform the MMSE-LE for various configurations.

Comparison of Square Section Drawings from Circular Billets through Cassette-Roller-Dies and Hole Die (카세트롤러와 홀다이를 이용한 원형소재에서 사각형 단면 인발 비교)

  • Choi J. I.;Han C. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.208-211
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    • 2001
  • In the drawing from round billet to non-circular section there are two different processes through solid hole die(HD) and the other cassette roller dies(CRD). The CRD process has several cassette type rollers and a billet is able to move through the given gaps between two profiled rollers. The objective of this study is based on the analysis and evaluation of two aforementioned processes using experiments and finite element simulation. In order to simulate the multi-stage drawing process from circular sectioned billet to rounded square section, the finite element analysis is applied to the process using a commercially available DEFORM-3D code. Two types of experimental drawing tests through designed and manufactured dies for pure copper and aluminum alloy are carried out at room temperature. The analysis included comparison of material properties before and after drawing of each process and also provide some useful information by a FEM simulation.

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Performance Analysis of STAP and SFAP in Jamming Environments (재밍 환경에 따른 STAP 및 SFAP 방식 성능 분석)

  • Kim, Kiyun
    • Journal of Satellite, Information and Communications
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    • v.10 no.4
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    • pp.136-140
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    • 2015
  • In this paper, a comparative studies on the STAP and SFAP were performed, which are known as representative anti-jamming technology for adaptive array antenna. As a method of estimating the weighting vector for simulation, MMSE(Minimum Mean Square Error) algorithm was commonly used and the analyses of the simulation performance in various jamming environments were presented. Especially, performance comparison between STAP and SFAP according to the jamming power J/S(Jamming to Signal Power Ratio), performance comparison in the ratio of jamming bandwidth to signal bandwidth, and performance comparison of BER between STAP and SFAP were presented.

A Comparison of Operation Characteristics for $3\Phi$Boost/Buck Converter to Inverter Arc Welding Machine (인버터 아크용접기를 위한 3상 승압/강압형 컨버터의 운전특성비교)

  • 최해룡;구영모;채영민;최규하;목형수;김규식;원충연
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.260-264
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    • 1998
  • Three phase Boost/Buck converter which have economical merits and simple control scheme, are analyzed and evaluated through comparative methods and digital simulation for equivalent load. Those play a part of voltage boost/buck as well as power factor correction with single switch. Controller operating in constant and variable frequency is used for rapid output response and stable system condition respectively. Moreover low THD property of single switched converters is available for inverter arc welding machine known as high power and low power factor. So, in this paper a comparison of the characteristics in boost and buck converter is described and then simulation results conforms the merits from point of view of power factor and voltage regulator.

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A Comparison of the Rotor Position Estimation of an SRM with Built-in Search Coils by Three Methods at a Standstill (세 가지 방법에 의한 서치코일 내장형 SRM의 정지시 회전자 위치 추정방법 비교)

  • Yang H. Y.;Shin D. S.;Lim Y. C.
    • Proceedings of the KIPE Conference
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    • 2004.07b
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    • pp.931-935
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    • 2004
  • This paper presents a comparison of the rotor position estimation of a switched reluctance motor(SRM) with built-in search coils. Squared euclidean distance, fuzzy logic and neural network are used to estimate the rotor position. The simulation is performed by three methods and the results are compared. The experiment of squared euclidean distance is achieved and compared with the simulation result.

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