• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.169-177
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• 2000

In machining screws which are important members in mono pumps or progressive cavity pumps CNC turning center with 3 axes is usually used. This sort of screw machining requires large amount of CL data points and rotational tools are used in machining. When working out the CL data points consideration of possible tool interference is important in order to avoid undercut. This paper describes the checking methods of tool interference in the screw machining on the CNC turning center. First of all a specific shape of a screw cross-section that could commonly be applied to all screws was chosen and then possible tool interference associated with that shape was identified. Checking method was mathematically developed and verified. This checking method will be utilized in the CAM system developed by the authors for screw machining on the 3-axis CNC turning center.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.26.2-26.2
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• 2008

YLPODS (Yonsei Laser-ranging Precise Orbit Determination System) is POD system using SLR (Satellite Laser Ranging) data. YLPODS is developed for two main purposes. The first purpose is to verify the result of POD using GPS data. The second purpose is to perform POD using only SLR data. In this study, YLPODS performance test is presented for checking the reliability of POD using only SLR data. To perform POD, the information of CHAMP and TOPEX mission is applied and SLR NP (Normal Point) data is used. The test is performed by checking both range precision and 3D accuracy (radial, along, cross direction). To confirm of 3D accuracy, CHAMP GENESIS orbit and TOPEX JPL orbit of NASA are used.

• Journal of Mechanical Science and Technology
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• v.16 no.4
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• pp.427-435
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• 2002

This paper presents a development result for image processed tracking system of multiple moving objects based on Kalman filter and a simple window tracking method. The proposed algorithm of foreground detection and background adaptation (FDBA) is composed of three modules: a block checking module(BCM), an object movement prediction module(OMPM), and an adaptive background estimation module (ABEM). The BCM is processed for checking the existence of objects. To speed up the image processing time and to precisely track multiple objects under the object's mergence, a concept of a simple window tracking method is adopted in the OMPM. The ABEM separates the foreground from the background in the reset simple tracking window in the OMPM. It is shown through experimental results that the proposed FDBA algorithm is robustly adaptable to the background variation in a short processing time. Furthermore, it is shown that the proposed method can solve the problems of mergence, cross and split that are brought up in the case of tracking multiple moving objects.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.73-78
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• 2023

It is very important to evaluate how the functions of products, facilities, and spaces affect human life. The evaluation of these actions has legal regulations such as certification, inspection, and diagnosis, and the degree of quality, safety, and excellence of the results is announced. This study sought to secure safety through efficient system operation by reviewing safety-related certification systems established and implemented by each government department in Korea and analyzing the characteristics of each system and similarities between systems. There was also an aspect of cross-checking safety through the certification and diagnosis system implemented by each ministry, but it was confirmed that the efficiency of the system should also be considered in terms of overlapping application. Therefore, when securing safety is confirmed based on each safety-related law, active alternatives such as exemption, substitution, delegation, etc. should be presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.7
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• pp.726-735
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• 2009

In this paper, we propose an approach to signal model-based fault detection and diagnosis system for induction motors. The current fault detection techniques used in the industry are limit checking techniques, which are simple but cannot predict the types of faults and the initiation of the faults. The system consists of two consecutive processes: fault detection process and fault diagnosis process. In the fault detection process, the system extracts the significant features from sound signals using combination of variance, cross-correlation and wavelet. Consequently, the pattern classification technique is applied to the fault diagnosis process to recognize the system faults based on faulty symptoms. The sounds generated from different kinds of typical motor's faults such as motor unbalance, bearing misalignment and bearing loose are examined. We propose two approaches for fault detection and diagnosis system that are waveletand-variance-based and wavelet-and-crosscorrelation-based approaches. The results of our experiment show more than 95 and 78 percent accuracy for fault classification, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.201-206
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• 2016

Aircraft have a cross axis of the three each other for maintenance of aircraft position. It is called roll axis, pitch axis and yaw axis. Attitude reference system is a sensor for detecting a change of the three axis. In this paper, mobile robot platform install part of Pan-tilt and HMD attitude reference system, because of we use control camera. The acceleration sensor is very weak a lot of noise to vibration, also problem with data from process of mapping to the data problems to arise. However to solve this problem, we removed the average filter and Cosine Interpolation for Pan-tilt. Using capacity evaluation for outdoor environment for we are proposing. Mobile robot has HMD and equipped Pan-tilt. We control mobile robot camera. In this experiment result is little bit delay happening, however Pan-tilt camera is relatively stable control checking. Also, we will checking any terrain and slopes is no problem for mobile robot driving skills.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.94-101
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• 2014

Recently, in order to reduce the time required to replace an optical jumper cord, many researchers are using a field-installable connector and applying the ferrule polishing method, ferrule mechanical contact method, or ferrule fusion contact method. However, the process of arranging the length of the optical fiber, i.e., inserting the optical fiber into the ferrule by hand and checking its cross section, takes 60% of the time required for the entire process, which increases the overall cost. Therefore, in order to make this task more cost-effective, we will develop an automated inspection system with automatic cross-sectional arrangement of a field-installable connector. This system will be able to decrease the failure rate from 10% to 2% compared with the conventional method when cutting the optical fiber inserted into the ferrule. It will also improve the productivity by decreasing the test time by 28% compared with the conventional method. Our studies showed that it was possible to reduce the production costs and improve the quality of a field-installable connector, and we expect it to dominate the market.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.411-416
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• 1999

The measurement of unsteady flow rate is of vital importance to clarify and improve the dynamic characteristics in pipeline, hydraulic components and system. There is also demand for a real time flow sensor of ability to measure unsteady flow rate with high accuracy and fast response to realize feedback control of flow rate in fluid power systems. In this paper, we propose an approach for estimating unsteady flow rate through a pipeline and components under high pressure condition. In the method, unsteady flow rate is estimated by using hydraulic pipeline dynamics and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-checking functions of the method, the validity is investigated by comparison with the measured and estimated pressure waveforms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate waveforms and theroetical those under unsteady laminar flow conditions. the method proposed here is useful in estimating unsteady flow rate through an arbitray cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.2
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• pp.62-67
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• 2009

LOSA is a flight safety program that analyses human errors in normal operations. Trained pilot observers monitor the normal flights at the observer seat. LOSA is a proactive non jeopardy data collection tool using threat and error management(TEM) as a framework. With the analysis of crew behaviors through LOSA with The LOSA collaborative(TLC), the airlines can identify the behaviors of the crew during normal operations. The major objective of LOSA is to measure how the crew manage threats, errors and undesired aircraft deviations in the cockpit on day to day operations. The airlines are able to set up effective TEM training with practical six generation Crew recourse management(CRM) with data of error from LOSA instead of theoretical CRM courses. The Airlines can use TEM as an integral part of a Safety Management System(SMS) and uses monitoring and cross-checking skills in the flight operations to manage threats and errors effectively when we know the errors we make in the cockpit on daily operation. The result of LOSA indicates that the error detection rate should be enhanced since around the half of the errors went undetected. The areas which should be focused for enhancing the error detection are monitor, cross-check, the management of workload, automation and taxiway/ runway to manage errors effectively.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.912-923
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• 2015

In the results of analyzing Korean corrective action for what are required to be improved according to EU listing Korea as yellow-card non-cooperating third countries against IUU fishing, in order to establish advanced fishery order, it is thought that the following additional improvements are required. (1) The introduction of integrated management system of fishing vessel sailing route, fishing activity, fish catch, and inshore fishing vessel must be considered. (2) It is necessary to establish a system to cross check catch transaction, catch landing, and fish catch report submitted by fishing vessel. (3) Catch transshipment approval system shall be introduced. And a system of reporting and checking catch transshipment at sea shall be reinforced. (4) Punishment shall be strengthened to the extent of making people to perceive that loss due to punishment is larger than profit made from illegal fishing. (5) It shall be so improved that more than a certain percentage of all vessels with fish and fish products caught in waters outside Korea's judicial waters shall be arbitrarily chosen and searched besides a case of being suspected to be IUU fishing. In conclusion, on being listed by EU as yellow-card non-cooperating third countries against IUU fishing, Korean fishery management system shall be generally reexamined, and it shall serve as an occasion to exterminate IUU fishing and to advance fishery management system.