• Journal of Positioning, Navigation, and Timing
• /
• v.5 no.4
• /
• pp.173-180
• /
• 2016

This paper presents a method to suppress multipath induced by pulses using supervised learning. In modern electronics, pulses have been used for various purposes such as communication or distance measurements. Like other signals, pulses also suffer from multipath. When a pulse and a multipath are overlapped, the original pulse shape is distorted. The distorted pulse could result in communication failures or distance measurement errors. However, a large number of samples available from a pulse can be used to effectively reject multipath by using a supervised learning method. This paper introduces how a supervised learning method can be applied to Distance Measuring Equipment. Simulation results show that multipath induced distance measuring error can be suppressed by 10 ~ 45 percent depending on the allowed pulse shape variation allowed in a standard.

• Journal of Positioning, Navigation, and Timing
• /
• v.10 no.2
• /
• pp.113-120
• /
• 2021

The Distance Measuring Equipment (DME) is a ground-based aircraft navigation system and is considered as an infrastructure that ensures resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS) outage. The main problem of DME as a GNSS back up is a poor positioning accuracy that often reaches over 100 m. In this paper, a novel approach of applying deep reinforcement learning to a DME pulse design is introduced to improve the DME distance measuring accuracy. This method is designed to develop multipath-resistant DME pulses that comply with current DME specifications. In the research, a Markov Decision Process (MDP) for DME pulse design is set using pulse shape requirements and a timing error. Based on the designed MDP, we created an Environment called PulseEnv, which allows the agent representing a DME pulse shape to explore continuous space using the Soft Actor Critical (SAC) reinforcement learning algorithm.

• Journal of Advanced Navigation Technology
• /
• v.19 no.6
• /
• pp.534-543
• /
• 2015

This paper introduces the time-misalignment error between multiple range measurements acquired by an onboard distance measuring equipment (DME) interrogator and proposes an efficient position determination method that can mitigate the negative effects of the time-misalignment error. The introduced time-misalignment error does not occur in conventional utilization of DME combined with VHF omnidirectional range (VOR). The proposed position determination method projects all the DME range measurements acquired irregularly during an interval to the same time instance where the aircraft position is determined. By the simulation utilizing a representative aircraft trajectory, it is shown that it is possible to estimate the horizontal position accurately without any changes of ground DME facilities.

• Proceedings of the KIEE Conference
• /
• 2004.04a
• /
• pp.266-268
• /
• 2004

In this study, on-line measuring system were developed to verify performances and functions of traction system that are used in KTX(Korea Train eXpress) synthetically and efficiently, and have been measuring electric signals of vehicle as well as mechanical signals up to the present. Running-braking measuring equipment was constructed in vehicle to optimize signal acquisition and analysis ability of the measuring system. Measurement data of signal were performed acquisition, analysis and evaluation using this equipment. KRRI(Korea Railroad Research Institute) described about main specifications of measuring equipment. Also, the structure and principles as well as main circuit system were explained in brief. KRRI analyzed the characteristics comparing design values with experimental values about running distance, running time and positive acceleration for KTX is running in full traction. We analyzed the distance and time according to number of motor block. In result, running characteristics of traction system in KTX were verified and could be evaluated.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.204-208
• /
• 2013

CO2 emission makes up more than 80% of whole green gas. Therefore CO2 is recognized as the main culprit of global warming. IPCC (Intergovernmental Panel on Climate Change) is advising the 3 methods measuring CO2 emission. TIER1 is measured CO2 emission by criteria the energy consumption, TIER2 measure by criteria the emission factor according to the emission control technique each kind of vehicle, TIER3 is measured by criteria the distance each kind of vehicle. Currently, the most of CO2 emission measurement is used by TIER1. But it is not standardized that CO2 emission measurement method have the factor as work condition each distance. Specially, it is not suggest that methodology has the condition changing load of equipment according to site condition and the same position work as construction equipment. So, this study is suggested the CO2 emission measurement methodology of construction equipment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.6
• /
• pp.1237-1243
• /
• 2001

This paper presents an information about the heat transfer characteristics of impinging jet in eletronic equipment with infrared image processing unit. There have been many experimental investigations and theoretical studies on impinging jet because of application in a wide variety of industrial process including electronic equipment. In this study, we used infrared image processing unit to visualize heat transfer characteristics of impinging jet in eletronic equipment. Infrared image processing unit is one of non-contact temperature measuring methods and it is possible to minimize flow resistance and this measurement is comparatively accurate. The main parameters are distance between nozz1e and heat source. Reynolds number is 6000.

• Korean Journal of Digital Imaging in Medicine
• /
• v.7 no.1
• /
• pp.39-44
• /
• 2005

Purpose of this research is that if Radiographer has focused on Radiation exposure research until now, he should realize that always exposed by Electro Magnetic Wave at given working environment And also, another purpose is that to minimize damage with measuring Electro Magnetic Wave which is happened area and distance of Radiation Control System and High Voltage Equipment, check occurrence rate and minimize damage from it.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.2
• /
• pp.48-54
• /
• 2005

The theodolite system consists of two theodolites, a scale bar and a target bu. A measurement accuracy of theodolite system is affected by a measurement distance of each equipment. This study was performed fir measuring an accuracy when the distance from theodolite to scale bar was changed 2~ 6 m on two theodolites distance 3 a The results showed thai the measurement accuracy could be $\pm$0.021 mm when the distance from theodolite to target was 2,3 and 6 n Specially, it was found that the maximum measurement accuracy was 10.017mm on theodolite collimation distance 3m and the distance 4 m of the theodolite and scale bar.

• Journal of IKEEE
• /
• v.24 no.3
• /
• pp.913-916
• /
• 2020

In this paper, we propose the development of nitrogen cooling equipment for personalized local area. The proposed equipment consists of a cold air supply module, a body, and nitrogen injection with the following characteristics. First, it automatically controls the amount and time of cold air supply by utilizing information measuring skin temperature with volumetric temperature sensors, so it can have a competitive edge in function by ensuring complete safety. Second, if the distance measuring sensor is applied to the skin for more than a certain distance, it can block the cold air or control the discharge of nitrogen in conjunction with the control GUI to improve the efficiency of higher cooling therapy while providing safe management. Third, by installing a control module that can control the supply of nitrogen, the cost of maintenance can be minimized by minimizing the loss of nitrogen. Experiments at an external testing agency to evaluate the performance of the proposed equipment showed that the accuracy of the temperature sensor was measured in the range of ±3.8%, which is lower than the world's highest level(±5%), with a range of 110℃ to -160℃ similar to the world's highest level. Distance accuracy was measured in the range of ±3.0%, lower than the world's highest level(±5%), and weight accuracy in the range of ±0.1%, lower than the world's highest level(±5%). In addition, emission control was measured in four stages, higher than the world's highest level(stage 1) and nitrogen use was measured at 0.8L/min below the world's highest(6L/min). Therefore, the effectiveness of the methods proposed in this paper was demonstrated because they produced the same results as the world's highest levels.

• Korean Journal of Digital Imaging in Medicine
• /
• v.11 no.1
• /
• pp.5-13
• /
• 2009

There are several reasons to take X-ray in case of inpatients. Some of them who cannot ambulate or have any risk if move are taken portable X-ray at their wards. Usually, in this case, many other people-patients unneeded X-ray test, family, hospital workers etc-are indirectly exposed to X-ray by scatter ray. For that reason I try to be aware of free space scatter dose accurately and make the point at issue of portable X-ray better in this study. kVp dose meter is used for efficiency management of portable X-ray equipment. Mobile X-ray equipment, ionization chamber, electrometer, solid water phantom are used for measuring of free space scatter dose. First of all the same surroundings condition is made as taken real portable X-ray, inquired amount of X-ray both chest AP and abdomen AP most frequently examined and measured scatter ray distribution of two tests individually changing distance. In the result of measuring horizontal distribution with condition of chest AP it is found that the mAs is decreased as law of distance reverse square but no showed mAs change according to direction. Vertical distribution showed the mAs slightly higher than horizontal distribution but it isnt found out statistical characteristic. In abdomen AP, compare with chest AP, free space scatter dose is as higher as five-hundred times and horizontal, vertical distribution are quite similar to chest AP in result. In portable X-ray test, in order to reduce the secondary exposure by free space scatter dose first, cut down unnecessary portable order the second, set up the specific area at individual ward for the test the third, when moving to a ward for the X-ray test prepare a portable shielding screen. The last, expose about 2m apart from patients if unable to do above three ways.