• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.285-289
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• 1995

This paper describes the determination of geoid using height data measured by GPS and Spirit Levelling. The GPS data of the 88 stations were used to determine the geoid undulation (N) which can be easily obtained by subtracting the orthometric height(H) from the ellipsoidal height(h). From the geoid undulation (N) calculated at each station mentioned above, geoid plots with a contour interval of 0.25 m were drawn using two interpolation methods. The following interpolation methods were applied and compared with each other: Minimum Curvature Method and Least Squares Fitted Plane. Comparison between geometric geoid and gravimetric geoid undulation by FFT technique was carried out.

• Journal of KSNVE
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• v.10 no.5
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• pp.886-891
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• 2000

In this paper, an iterative array shape estimation technique is presented, which is based on the use of the least squares polynomial fitting to the data from heading sensors. The estimated polynomial shape model is then used for calculating the hydrophone positions on the assumption that the arc distances between sensors are constant. In order to verify the applicability of the proposed algorithm, numerical simulations are performed using two types of non-linear array shapes. In addition the noise effects of heading sensors on the array shape estimation results and the performance of beamformer are also investigated.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.39-44
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• 2017

This paper proposes a novel approach to determine symmetrical components of power system by applying method of least squares in time domain. For the modern power system stability, clearance of faults on high voltage transmission lines in zero response time is crucial and important. Symmetrical components have a great attention since last century. They have been found an effective tool for the analysis of symmetrical and unsymmetrical faults in power system. Moreover, magnitude of symmetrical components are also used as a caution about faults in system. With rapid changes in technology, Microprocessor assumed to be fastest machine of the modern era. Hence microprocessor based techniques were developed and implemented for last few decades. The proposed technique apply least square method in the computation of symmetrical components which is suitable as an application in microprocessor based monitoring and controlling power system in order to avoid cascading failures. Simulation of proposed model is carried out in MATLAB/SIMULINK and all results exploit the validity of model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.129-133
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• 2019

Frequency resource efficiency is important in satellite communication systems. One of the causes of a waste of frequency resource is bad flatness. In the case, flatness of satellite Tx terminals would be worse by ACI and guard band. In order to overcome this problem, this paper proposes a technique for frequency response equalization in satellite Tx terminals. First of all, a general linear polynomial expression which meets least squares of representative measurement data is calculated to interpolate unmeasured data. And then flatness can be adjusted using the polynomial expression. Simulation results illustrate adjusted data have lower peak to peak and standard deviation than original data, and these show that flatness be improved.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.1267-1274
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• 2021

This study aims to analyze the effect of corporate communication and service quality on loyalty mediating satisfaction. The population of this study is 384 Islamic bank customers in North Sumatra. This research is quantitative research using the survey method. The number of research samples was 384 customers. Characteristics of this research sample were (1) Savings customers who actively carried out transactions in Islamic banks (2) Savings customers who had used bank services for at least 1 year (3) Savings customers who used services directly and individually. The data analysis technique used in this study was the Partial Least Squares-Structural Equation Model (SEM-PLS) analysis technique, using Warp-PLS 3.0 software. This study investigates the largest Islamic banks in North Sumatra, namely Bank Syariah Mandiri, Bank BNI Syariah, and Bank BRI Syariah. The results show that company communication has a positive and significant effect on satisfaction, service quality has a positive and significant effect on satisfaction, company communication has a positive and significant effect on loyalty, service quality has a positive and significant effect on loyalty, satisfaction has a positive and significant effect on loyalty. There is also a significant effect of satisfaction on the relationship between company communication and loyalty, and the relationship between service quality and loyalty. This study contributes to Islamic banking to increase customer loyalty.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.400-407
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• 1995

The straightness property is one of fundamental geometric tolerances to be strictly controlled for guideways of machine tools and measuring machines. The staightness measurement for long guideways was usually difficult to perform, and it needed additional equipments or special treatment with limited application. In this paper, a new approach is proposed using the profile matching technique for the long guideways, which can be applicable to most of straghtness measurements. An edge of relativelly sthort length is located along a divided section of a long guideway, and the local straightness measurement is performed. The edge is then moved to the next section with several positions overlap. After thelocal straightness profile is measured for every section along the long guideway with overlap, the global straightness profile is constructed using the profile matching technique based on theleast squares method. The proposed techinique is numerically tested for two cases of known global straightness profile arc profile and irregular profile and those profiles with and without random error intervention, respectively. When norandom errors are involved, the constructed golval profile is identical to the original profile. When the random errors are involved, the effect of the number of overlap points are investigated, and it is also found that the difference between the difference between the constructed and original profiles is very close to the limit of random uncertainty with juist few overlap points. The developed technique has been practically applied to a vertical milling machine of moving table type, and showed good performance. Thus the accuracy and efficiency of the proposed method are demonstrated, and shows great potential for variety of application for most of straightness measuirement cases using straight edges, laser optics, and angular measurement equipments.

• Tunnel and Underground Space
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• v.20 no.2
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• pp.97-104
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• 2010

The materials failure relation $\ddot{\Omega}=A{(\dot{\Omega})}^\alpha$ where $\Omega$ is a measurable quantity such as displacement and the dot superscript is the time derivative, may be used to analyze the accelerating creep of materials. Coefficients, A and $\alpha$, are determined by fitting given data sets. In this study, it is tried to predict the failure time of tunnel using the materials failure relation. Four fitting techniques of applying the materials failure relation are attempted to forecast a failure time. Log velocity versus log acceleration technique, log time versus log velocity technique, inverse velocity technique are based on the linear least squares fits and non-linear least squares technique utilizes the Levenberg-Marquardt algorithm. Since the log velocity versus log acceleration technique utilizes a logarithmic representation of the materials failure relation, it indicates the suitability of the materials failure relation applied to predict a failure time of tunnel. A linear correlation between log velocity and log acceleration appears satisfactory(R=0.84) and this represents that the materials failure relation is a suitable model for predicting a failure time of tunnel. Through comparing the real failure time of tunnel with the predicted failure times from four curve fittings, it is shown that the log time versus log velocity technique results in the best prediction.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.197-198
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• 2011

A technique to manage harmonic pollution at the point of common coupling (PCC) has been presented using a control chart. The recursive least-squares technique has been used to estimate the parameters of the Thevenin equivalent load model. With the estimated data from the measured voltage and current waveform at the PCC during certain period violating upper control limit, the individual contributions to the distortion of voltage waveform at an interested harmonic frequency have been calculated and shown by simple graph.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.2
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• pp.72-81
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• 2000

In this paper, we design an adaptive neuro-fuzzy inference system(ANFIS) precompensator for load frequency control of 2-area power systems. While proportional integral derivative (PID) controllers are used in power systems, they may have some problems because of high nonlinearities of the power systems. So, a neuro-fuzzy-based precompensation scheme is incorporated with a convectional PID controller to obtain robustness to the nonlinearities. The proposed precompensation technique can be easily implemented by adding a precompensator to an existing PID controller. The applied neruo-fuzzy inference system precompensator uses a hybrid learning algorithm. This algorithm is to use both a gradient descent method to optimize the premise parameters and a least squares method to solve for the consequent parameters. Simulation results show that the proposed control technique is superior to a conventional Ziegler-Nichols PID controller in dynamic responses about load disturbances.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1412-1415
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• 1996

In this paper, a new identification method of the cascade control system is proposed which can overcome the weak points of Krishnaswamy and Rangaiah(1987)'s method. This new method consists of two steps. One is on-line process identification using the numerical integration to approximate the two process dynamics with a high order linear transfer function. The other is a model reduction technique to derive out low order transfer function(FOPTD or SOPTD) from the obtained high order linear transfer function to tune the controller using usual tuning rules. While the proposed method preserves the advantages of the Krishnaswamy and Rangaiah(1987)'s method, it has such a simplicity that it requires only measured input and output data and simple least-squares technique. Simulation results show that the proposed method can be a promising alternative in the identification of cascade control systems.