• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.844-851
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• 2018

In this study, the regression equation was suggested to predict of the shot ball velocity according to blade shapes based on discrete element (DE) analysis. First, the flat type blade DE model was used in the analysis, the validity of the DE model was verified by giving that the velocity of the shot ball almost equal to the theoretical one. Next, the DE analyses for curved and combined blade models was accomplished, and their analytical velocities of shot ball were compared with the theoretical one. The velocity of combined blade model was greatest. From this, the regression equation for velocity of shot ball according to the blade shape based on the DE analysis was derived. Additionally, the wind speed measurement experiment was carried out, and the experimental result and analytical one were the same. Ultimately, it was confirmed that the prediction method of the velocity of shot ball based on DE analysis was effective.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.343-349
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• 2007

One of the useful technologies for light-weightening of components required in the automobile and machine industry is to use high strength materials. To improve material properties, the carbonizing treatment, nitrifying treatment, and shot-peening method are representatively applied. However, the shot-peening method is generally used to remove surface defect on steel and to improve the fatigue strength of the surface. Benefits of shot-peening are increasing resistance against fatigue, stress corrosion cracking, fretting, galling, erosion and closing of pores. In this paper, the effect of shot-peening on the corrosion of SUP-9 steel immersed in a 3.5% NaCl solution and corrosion characteristics from heat treatment during the shot peening process has been investigated. The immersion test was performed on four kinds of specimens. Corrosion potential, the polarization curve, residual stress etc. Were analyzed from the experimental results.

• Journal of Applied Reliability
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• v.17 no.1
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• pp.1-10
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• 2017

Purpose: This study aims at omitting the initial testing of the ASRP by determining the initial test year. Methods: This study is to determine of the initial test year for one-shot system using validity assessment of drugs. Results: Procedures for determining the initial test duration of the one shot system and examples of omitting the tests are presented. Conclusion: Using this method, the time and labor required for testing can be saved by omitting the initial testing of ASRP.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.435-441
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• 2012

This paper provides simulation-based results of effect analysis of sample size and sampling periods on accuracy of reliability estimation methods using multiple comparisons with analysis of variance. Sum of squared errors in estimated reliability measures were evaluated through applying seven estimation methods for one-shot systems to simulated quantal-response data. Analysis of variance was implemented to investigate change in these errors according to variations of sample size and sampling periods for each estimation method, and then the effect analysis on accuracy in reliability estimation was performed using multiple comparisons based on sample size and sampling periods. An efficient way to allocate both sample size and sampling periods for reliability estimation tests of one-shot systems is proposed in this paper from the effect analysis results.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.305-309
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• 2011

Reliability evaluation of One-Shot systems which fly at speed of Mach must evaluate as the result which leads a many firing test. But many firing test the fact that is impossible is actuality with problem of budget. Method of prediction leads consequently with alternative and will be able to present the alternative which evaluates. Prediction of One-Shot systems that how many did accumulate a many experience data according to the accuracy is decided, there is a possibility of seeing. One like shot our country and the method which is indirect leads from the environment where the test data is insufficient and only will not be able to set the direction of prediction, the present paper about such method describes 217 Plus where is a reliability prediction standard which is new the thing in standard.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1291-1298
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• 2011

This paper proposes a new reliability estimation method for one-shot systems using quantal response data, which is based on a parametric estimation method. The proposed method considers the time-variant failure ratio of the quantal response data and it can overcome the problems in parametric estimation methods. Seven reliability estimation methods in the literature were compared with the proposed method in terms of the accuracy of reliability estimation in order to verify the proposed method. To compare the accuracy of reliability estimation, the SSEs (Sum of Squared Error) of the reliability estimation results for the different estimation methods were evaluated according to the various numbers of samples tested. The proposed method provided more accurate reliability estimation results than any of the other methods from the results of the accuracy comparison.

• Journal of Digital Convergence
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• v.7 no.2
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• pp.93-102
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• 2009

Since video is composed of unstructured data with massive storage and linear forms, it is essential to conduct various research studies to provide the required contents for users who are accustomed to dealing with standardized data such as documents and images. Previous studies have shown the occurrence of undetected and false detected shots. This thesis suggested shot verification and video retrieval system using visual rhythm to reduce these kinds of errors. First, the system suggested in this paper is designed to detect the parts easily and quickly, which are assumed as shot boundaries, just by changing the visual rhythm without playing the image. Therefore, this enables to delete the false detected shot and to generate the unidentified shot and key frame. The following are the summaries of the research results of this study. Second, during the retrieving process, a thumbnail and keyword method of inquiry is possible and the user is able to put some more priorities on one part than the other between the color and shape. As a result, the corresponding shot or scene is displayed. However, in the case of not finding the preferred shot, the key picture frame of similar shot is supplied and can be used in the further inquiry of the next scene.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.628-633
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• 2020

This paper presents an analysis of the shelf-life management program of the long-term storage one-shot system. The one-shot system is mainly maintained with long-term storage or non-operating status and is operated once at execution of the mission. The function corresponding to one-shot is mainly operated through a shelf-life item such as an explosive. The performance and characteristics of shelf-life item are subject to change as the storage period passes. Therefore, shelf-life management for maintaining good condition is very important during long-term storage, and criteria for management is necessary. We present a method for optimizing shelf-life extension by comparing criteria for management with current reliability. Next, the shelf-life evaluation schedule was decided by utilizing the reliability function of exponential distribution and Weibull distribution. Continuously accumulated test data from the shelf-life evaluation were analyzed, and the parameter of distribution was updated. The extension or expiration of shelf-life was selected by monitoring changes in reliability. In addition, we confirmed the applicability of the presented shelf-life management program by applying ASRP test data of the one-shot system K000 fuse.

• Design & Manufacturing
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• v.8 no.2
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• pp.18-22
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• 2014

Two shot molding is one of the injection method which uses two materials or two color materials simultaneously in one mold. Two shot molding is good rate of productivity and economical because of no extra-progress necessary. The cowl grille is located in the bottom of wind shield glass and rolls as a passage of air inlet to inside of vehicle. It consists of body and seal. Firstly, the body is injected with PP. Next seal is extruded with EPDM and engineered and then assembled with body. These procedures lead high cost of production and the quality of part has problems. Therefore, it has effects on saving production cost and being a solution of the quality problems with the development of two shot molding cowl grille. It is guaranteed that two shot molding will be widely used in the vehicle parts industry afterwards.

• Journal of Advanced Navigation Technology
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• v.26 no.4
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• pp.195-204
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• 2022

In this paper, we described the rapid initial alignment techniques of projectile navigation system for use in inclined launch systems. One-shot alignment technique, one of the rapid initial alignment techniques, is possible to align a navigation system within seconds because it uses external information from an launcher navigation system. However, since it has only been used in vertical launch systems, its performance in inclined launch systems has not been verified. Therefore, this paper analyzed the error elements that occur when the one-shot alignment technique is applied to the inclined launch system, and introduced a method to improve the alignment performance by minimizing those errors. Additionally, By simulating and testing the performance of the proposed alignment technique, it was verified that it is effective even in an environment where a real navigation system is used.