• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.254-259
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• 2002

A variable air-gap type system is widely used for inductive precision position measurement systems. This type transducer has high sensitivity but lacks a linear measurement range due to structural nonlinearity. Furthermore, as measurement range increases, linearity error is also increased. The alternative is a variable overlap-area type system. The sensitivity of this type is determined by the initial air-gap dimension, keeps the original value and does not deteriorate linearity in spite of the variations of the measuring range.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.244-252
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• 2005

Accurate and reliable tracking of train is essential for a train control system. The fixed block system which utilizes the track circuit has been used widely for detecting train position. As an alternative, the moving block system has the advantage over the fixed block system since it enables shorter headway and easier maintenance. This paper presents a new technique for the train tracking system which uses radio signal for the train position detection. The proposed algorithm uses the phase difference of arrival of radio signal for the detection of train position. Experimental verification of the algorithm is presented in the paper.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.35-41
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• 2015

Multilateration(MLAT) is commonly used in civil and military surveillance applications to accurately locate an aircraft, vehicle or stationary emitter. MLAT calculates the TDOA of signals by transmitted aircraft and determines the aircraft's location. With more than four receivers it is possible to estimate the 3D position of the aircraft by calculating the intersection of the resulting hyperbolas and the system integrity. In this study, our objectives are to apply MLAT technique to Jeju terminal control area and to propose a MLAT receiver network to properly estimate the positions of aircraft approaching this area. Based on computer simulations, we determine locations of ground receivers in Jeju terminal control area, calculate estimated position errors of the aircraft with respect to the selected receiver networks, and find the best receiver network with the least position error.

• Journal of the Korean earth science society
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• v.35 no.6
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• pp.484-497
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• 2014

This study aimed to investigate high school students' conceptions of plate tectonics. Seventy students (N=70) in their 2 year of high schools in the province of Chungcheong-do participated in this study, and they took a conception test of visual representation. We conducted a semi-structured interview with 10 volunteering participants out of seventy. After learning about the concept of plate tectonics, this study found that participants ended up having alternative conceptions relating to terminology, meaning of colors, plates' movement, plates' boundaries, position and cause of melting, mantle's physical conditions, and driving forces of plate motion. The conceptions that the participants held after class were organically related, which included the meaning of colors, mantle's physical characteristic, and driving forces of plate movement. In addition, the visual representation used for teaching plate tectonics influenced the students' understanding about terminologies, plates' boundaries, position of melting, and the physical characteristic of mantle. The study found that there were the factors of visual representation that caused the learners to create alternative conceptions in learning about plate tectonics.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.9
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• pp.898-902
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• 2015

Alternative radio-navigation technologies aim at providing continuous navigation solution even if one cannot use GNSS (Global Navigation Satellite System). In shadowing region such as indoor environment, GNSS signal is no longer available and the alternative navigation system should be used together with GNSS to provide seamless positioning. For soldiers in battlefield where GNSS signal is jammed or in street battle, the alternative navigation system should work without positioning infrastructure. Moreover, the radio-navigation system should have scalability as well as high accuracy performance. This paper presents a TWR (Two-Way-Ranging)-based cooperative positioning system (CPS) that does not require location infrastructure. It is assumed that some members of CPS can obtain GNSS-based position and they are called mobile anchors. Other members unable to receive GNSS signal compute their position using TWR measurements with mobile anchors and neighboring members. Error propagation in CPS is analytically studied in this paper. Error budget for TWR measurements is modeled first. Next, location error propagation in CPS is derived in terms of range errors. To represent the location error propagation in the CPS, Location Error Propagation Indicator (LEPI) is proposed in this paper. Simulation results show that location error of tags in CPS is mainly influenced by the number of hops from anchors to the tag to be positioned as well as the network geometry of CPS.

• Journal of Astronomy and Space Sciences
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• v.35 no.4
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• pp.227-233
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• 2018

This study presents the generation and accuracy assessment of predicted orbital ephemeris based on satellite laser ranging (SLR) for geostationary Earth orbit (GEO) satellites. Two GEO satellites are considered: GEO-Korea Multi-Purpose Satellite (KOMPSAT)-2B (GK-2B) for simulational validation and Compass-G1 for real-world quality assessment. SLR-based orbit determination (OD) is proactively performed to generate orbital ephemeris. The length and the gap of the predicted orbital ephemeris were set by considering the consolidated prediction format (CPF). The resultant predicted ephemeris of GK-2B is directly compared with a pre-specified true orbit to show 17.461 m and 23.978 m, in 3D root-mean-square (RMS) position error and maximum position error for one day, respectively. The predicted ephemeris of Compass-G1 is overlapped with the Global Navigation Satellite System (GNSS) final orbit from the GeoForschungsZentrum (GFZ) analysis center (AC) to yield 36.760 m in 3D RMS position differences. It is also compared with the CPF orbit from the International Laser Ranging Service (ILRS) to present 109.888 m in 3D RMS position differences. These results imply that SLR-based orbital ephemeris can be an alternative candidate for improving the accuracy of commonly used radar-based orbital ephemeris for GEO satellites.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.333-335
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• 2006

Position of surface objects can be fixed in many ways. The most popular radionavigational systems, including satellite systems, make possible obtaining nearly continuous and very precise ship's position. However, under the water application of radionavigational systems is impossible. Underwater navigation requires other tools and solutions then these encountered in surface and air navigation. In underwater environment vehicles and submarines, operate that have to possess alternative navigational systems. Underwater vehicles, in order to perform their tasks require accurate information about their own, current position. At present, they are equipped with inertial navigational systems (INS). Accuracy of INS is very high but in relatively short periods. Position error is directly proportional to time of working of the system. The basic feature of INS is its autonomy and passivity. This characteristic mainly decides that INS is broadly used on submarines and other underwater vehicles. However, due to previously mentioned shortcoming i.e. gradually increasing position error, periodical calibration of the system is necessary. The simplest calibration method is surface or nearly surface application of GPS system. Another solution, which does not require interruption of performed task and emergence on the surface, is application of comparative navigation technique. Information about surrounding environment of the ship, obtained e.g. by means sonic depth finder or board sonar, and comparing it with accessible pattern can be used in order to fix ship's position. The article presents a structure and a description of working of underwater vehicle navigation system simulator. The simulator works on the basis of comparative navigation methods which exploit in turn digital images of echograms and sonograms. The additional option of the simulator is ability to robust estimation of measurements. One can do it in order to increase accuracy of position fixed with comparative navigation methods application. The simulator can be a basis to build future underwater navigation system.

• Korean Journal of Adult Nursing
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• v.19 no.3
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• pp.447-458
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• 2007

Purpose: This exploratory study was to identify the use of complementary and alternative medicine(CAM) in women with breast cancer and to analyze which factor influence CAM use. Methods: 114 patients with breast cancer were identified and approached. The instrument used to gather data were the common types, main reasons and effects as well as stress, mood states and fatigue. Results: 42.7% of all participants reported the use of CAM. The most common types of CAM used were Phellinus linteus, elm tree, and vitamin C. The main reasons for CAM use were to boost the immune system and to prevent recurrence. Prayer, massage, Shitake mushroom, and Ganoderma lucidum were, identified as being more effective than others. 93.6% of the respondents informed their physicians of their use of CAM. Logistic regression analysis determined that stress, mood states, and duration after diagnosis were factors significantly associated with CAM use. Conclusion: CAM use is increasing among patients with breast cancer. Health care professionals are in the main position to identify what treatments patients are using and implement CAM therapies that can be helpful to relieve patient symptoms related to treatment and psychological distress.

• Korean Journal of Adult Nursing
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• v.15 no.3
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• pp.402-410
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• 2003

Purpose: The purpose of this study was to develop a fundamental reference for the clinical implementation of Complementary and Alternative Therapy(CAT) by surveying and analyzing different perception and attitude between nurses and physicians. Method: A total of 167 nurses and 103 physicians from two C university health science centers participated in this survey, and SPSS program with version 10.0 was used to analyze the result of survey. Result: As results, 72.7% nurses and 57.1% physicians showed positive attitude for the concept of CAT, 60.6% nurses and 36.7% physicians responded positively while 2.6% nurses and 25.9% physicians responded negatively for the application of CAT to the clinical practice. There was a meaningful difference between two groups in the belief of therapeutic effectiveness of CAT. 67.7% nurses believed the therapeutic effectiveness of CAT while 38.8% physicians did. For attitudes of nurses and physicians toward CAT showed meaningful difference according to general characteristics: age, gender, marital status, a level of education, position in the organization, religion, and duration of health care service other than inpatient units. Conclusion: In this study, the attitudes of nurses and physicians about CAT showed meaningful difference that nurses were more positive than physicians in application.

• Journal of Arbitration Studies
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• v.19 no.2
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• pp.73-94
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• 2009

There are significant differences between disputes among enterprises and disputes between consumers and an enterprise. A majority of consumers may suffer from the same damages at the same time with small amount concerned and sometimes low chances for find the real cause. Among these distinctive features, the most significant characteristic in consumer-business disputes can be found in that consumers are in a disadvantageous position compared to businesses. When it comes to consumer policy, the biggest aim lies with turning back the damage a consumer is suffering into normalcy. In this regard, the Consumer Dispute Resolution System is the most essential among consumer policies. In Korea, the Collective Alternative Dispute Resolution (ADR) System was introduced to the Consumer Dispute Resolution System in 2007 in line with revision on the Consumer Basic Law. However, smooth damage redress for consumers is still not taking place. Against this backdrop, this report suggests that 'consumer arbitration' program should be introduced to the Consumer Dispute Resolution System as part of making good and smooth progress for consumer damage redress.