• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.6
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• pp.323-334
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• 2014

In this paper, we proposed indoor positioning system with improved accuracy. The proposed indoor location measurement system is based pedestrian location measurement method that use the embedded sensor of smartphone. So, we do not need wireless external resources, such as GPS or WiFi signals. The conventional methods measure indoor location by generating a movement route of pedestrian by step and direction recognition. In this paper, to correct the direction sensor error, we use the common feature of the normal indoor floor map that the indoor path is lattice-structured. And we quantize moving directions depending on the direction of indoor path. In addition, we propose moving direction measuring method using geomagnetic sensor and gyro sensor to improve the accuracy. Also, the proposed step detection method uses angle and accelerometer sensors. The proposed step detection method is not affected by the posture of the smartphone. Direction errors caused by direction sensor error is corrected due to proposed moving direction measuring method. The proposed location error correction method corrects location error caused by step detection error without the need for external wireless signal resources.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.2
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• pp.99-106
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• 2003

In this paper, an intelligent fault location and diagnosis system is proposed. The proposed system identifies the fault location in two-step procedure. The first step identifies candidates of fault location using an fault distance calculation using an iterative method. The second step is diagnosis the actual fault location in the candidates by comparing the current waveform patterns with the expected operation of the protective devices and considering the interrupted load after the operation protective device. The simulations results in the case study demonstrates a good performance of the proposed fault location and diagnosis system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.234-235
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• 2017

In order to improve the frictional resistance of existing high-speed planning hull, a step-like linear transformation has been researched which forms an air layer on the bottom. However, there is a lack of research on the proper position to confirm the effect of Running Attitude and step on each position. In this study, we confirmed the change of the Running Attitude, the effect of the step and the change of the frictional resistance when the step was applied in the longitudinal location.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1583-1589
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• 2016

This paper proposes an improved spread spectrum time domain reflectometry (ISSTDR) using time-frequency correlation and reference signal elimination method in order to have more accurate fault determination and location detection than conventional (SSTDR) despite increased signal attenuation due to the long distance to cable fault location. The proposed method has a two-step process: the first step is to detect a peak location of the reference signal using time-frequency correlation analysis, and the second step is to detect a peak location of the correlation coefficient of the reflected signal by removing the reference signal. The proposed method was validated through comparison with existing SSTDR methods in open-and short-circuit fault detection experiments of low voltage power cables. The experimental results showed that the proposed method can detect correlation coefficients at fault locations accurately despite reflected signal attenuation so that cable faults can be detected more accurately and clearly in comparison to existing methods.

• Journal of Information Technology Applications and Management
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• v.12 no.1
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• pp.157-172
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• 2005

Recently, location-based service (LBS) is a hot issue in the field of computer applications. So many papers introducing new techniques of implementing a LBS and new application fields of LBS have been published recently. However, to the best of our knowledge, none of them discusses feasibility test in the prior to the implementation. The importance of a feasibility test for a design prior to the implementation cannot be overemphasized. This paper presents a method of feasibility test for a LBS design. Our method performs three steps. At the first step, we build a Petri net model of the LBS system which is depicted in natural language. The second step is to analyse the Petri net to find errors and flaws in the design. We also improve the Petri net model by fixing the errors and flaws in this step. A feasibility test is the third and final step. In this step. we verify if the design satisfies the user's requirement in the senses of quality of service (QoS) and of minimizing the implementation cost. The third step is performed in the manner of mathematical analysis of the Petri net.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.829-835
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• 2008

The objective of this study is to present the two-step dispatching strategy for the purpose of the transport vehicle with multi-function used in container terminal. The two-step dispatching is a method to save the waiting time between transport vehicle and cranes using real time location control. The first step dispatching is to allocate the destination location based on the real time location information. The second step dispatching is to indicate the specific job such as loading, unloading, and pick-up based on the condition of working area. This two-step dispatching strategy decreases the waiting times of the stevedoring system and will contribute at a productivity improvement in container terminal.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1122-1129
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• 2015

This paper suggests a method of detecting traffic lights for vehicles by combining the HSV(hue saturation value) color model, morphometric characteristics, and location information appearing on consecutive images in daytime. In order to detect the traffic light, the color corresponding to the signal lights should be explored. It is difficult to detect traffic lights among colors of lights from buildings, taillight of cars, leaves, placards, etc. The proposed algorithm searches for the traffic lights from many candidates using morphometric characteristics and location information in consecutive images. The recognition process is divided into three steps. The first step is to detect candidates after converting RGB channel into HSV color model. The second step is to extract the boundaries between the housing of traffic lights and background by exploiting the assumption that the housing has lower brightness than the surrounding background. The last step is to recognize the signal light after eliminating the false candidates using morphometric characteristics and location information appearing on consecutive images. This paper demonstrates successful detection results of traffic lights from various images captured on the city roads.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2058-2065
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• 2010

This paper presents the sensor location and step estimation algorithm for personal navigation system (PNS). PNS has the disadvantage in that the position of the sensor must be fixed on a human body. Three-axis acceleration sensor is used to solve the disadvantage and to consider the real situation. We simplify the measurement data by using the band pass filter, witch It has the advantage in the detection of characteristic point. Through the detected characteristic points, it is possible to setup the parameter for the pattern detection. Depending on the sensor location, the parameters have the different type of noise covariance. Particularly, when the position of the sensor is changed, the impulse noise shows up. Considering the noise, we apply the recursive least square algorithm using the variable forgetting factors, which can classify the sensor location based on the estimated parameters. We performed the experiment for the verification of the proposed algorithm in the various environments. Through the experimental results, the effectiveness of the proposed method is verified.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.10
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• pp.563-570
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• 2003

When a fault occurs on railway feeders it is very important to detect the fault to protect trains and facilities. Because a DC railway system has low feeder voltage, The fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases at one time. So the type of $\Delta$I/ relay(50F) was developed using the different characteristics between the load starting current and the fault current. The load starting current increases step by step so the time constant of each step is much smaller than that of the fault current. First, to detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares is presented in this paper. If a fault occurs on DC railway systems it is necessary to find a fault location to repair the faulted system as soon as possible. The second aim of the paper is to calculate the accurate fault location using Kirchhoff's voltage law.

• Research in Community and Public Health Nursing
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• v.1 no.1
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• pp.503-517
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• 1989

This study is to analyze factors affecting the school nurse's activities. The survey was undertaken during Sept. 1-Nov. 30, 1986. The subjects were 137 school nurses from elementary, junior-high, and senior-high schools in Daegu City and Kyungppk Province. The results are as follows: 1. Correlational findings between school nurse's self-confidence and their general characteristics 1) Program Planning & Evaluation: Health Experinece(r=-0.1803, p<0.05) Salary Step(r=-0.1741, p<0.05) 2) Clinic Management: Salary STep(r=-0.2580, p<0.01) 3) Health Education: Salary Step(r=-0.1929, p<0.05) 4) Management of School Environment: Salary Step(r=-0.2501, p<.05) 5) Health Care Services: Health Experience(r=0.1901, p<0.05) Salary Step(r=-0.2424, p<0.05) 2. The degrees of school nurse's self-confidence(high: 4 point, low: 1 point) 1) Clinic Management: 2.92 2) Health Education: 2.86. 3) Program Planning & Evaluation: 2.74 4) Health Care Services: 2.73 5) Management of School Environment: 2.67 6) Operating of School Health Organization: 2.42 3. Significances to self-confidence on school nurse's activities 1) Program Planning as Evaluation: Expending Times for Health Care Services (r=-0.2262, p<0.05) Expending Times for Health Education (r=0.2943, p<0.05) Size of Clinic(r=0.2163, p<0.05) Location of Clinic(t=2.43, gH0.047) Use of Clinic(t=2.06, p<0.007) 2) Clinic Management: Location of Clinic (t=3.36, p<0.010) 3) Health Education: Purchase of Medicine(r=-0.1736, p<0.05) No, of Classes (r=-0.1794, p<0.05) (4) Management of School Environment: School Health Budget(r=0.1731, p<0.05) Home Message(r=0.1805, p<0.05) Location of Clinic(t=4.46, p<0.0001) 5) Operating of School Health Organization: School Health Budget(r=0.1878, p<0.05) Use of Clinic(t:1.90, p<0.018) 6) Health Care Services: School Health Budget(r=1.90, p<0.018) Expending Times for Health Education(r=0.2577, p<0.05) Size of Clinic(r=0.4336, p<0.001) Location of Clinic(t:5.10, p<0.001)