• 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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.96-104
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• 2017

A one-shot system (device) refers to a system that is stored for a long period of time and is then disposed of after a single mission because it is accompanied by a chemical reaction or physical destruction when it operates, such as shells, munitions in a defense weapon system and automobile airbags. Because these systems are primarily related with safety and life, it is required to maintain a high level of storage reliability. Storage reliability is the probability that the system will operate at a particular point in time after storage. Since the stored one-shot system can be confirmed only through inspection, periodic inspection and maintenance should be performed to maintain a high level of storage reliability. Since the one-shot system is characterized by a large loss in the event of a failure, it is necessary to determine an appropriate inspection period to maintain the storage reliability above the reliability goal. In this study, we propose an optimal inspection policy that minimizes the total cost while exceeding the reliability goal that the storage reliability is set in advance for the one-shot system in which periodic inspections are performed. We assume that the failure time is the Weibull distribution. And the cost model is presented considering the existing storage reliability model by Martinez and Kim et al. The cost components to be included in the cost model are the cost of inspection $c_1$, the cost of loss per unit time between failure and detection $c_2$, the cost of minimum repair of the detected breakdown of units $c_3$, and the overhaul cost $c_4$ of $R_s{\leq}R_g$. And in this paper, we will determine the optimal inspection policy to find the inspection period and number of tests that minimize the expected cost per unit time from the finite lifetime to the overhaul. Compare them through numerical examples.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.32-40
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• 2016

Purpose: The purpose of this study is to analyze the effect of sampling points on accuracy of storage reliability estimation for one-shot systems by assuming a weibull distribution as a storage reliability distribution. Also propose method for determining of sampling points for increase the accuracy of reliability estimation. Methods: Weibull distribution was divided into three sections for confirming the possible to estimate the parameters of the weibull distribution only some section's sample. Generate quantal response data for failure data. And performed parameter estimation with quantal response data. Results: If reduce sample point interval of 1 section, increase the accuracy of reliability estimation although sampling only section 1. Even reduce total number of sampling point, reducing sampling time interval of the 1 zone improve the accuracy of reliability estimation. Conclusion: Method to increase the accuracy of reliability estimation is increasing number of sampling and the sampling points. But apply this method to One-shot system is difficult because test cost of one-shot system is expensive. So propose method of accuracy of storage reliability estimation of one-shot system by adjustment of the sampling point. And by dividing the section it could reduce the total sampling point.

• Industry Promotion Research
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• v.7 no.4
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• pp.1-8
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• 2022

There are many one-shot devices that are used once and thrown away. One-shot devices such as firecrackers and ammunition are typical, and they are stored for a while after manufacture and then disposed of after use when necessary. However, unlike general operating systems, these one-shot devices have not been properly evaluated. This study first examines what the government does to secure reliability in the case of ammunition through ammunition stockpile reliability program. Next, in terms of statistical analysis, we show what the reliability analysis methods are for one-shot devices such as ammunition. Specifically, we show that it is possible to know the level of reliability if sampling inspection plan such as KS Q 0001 which is acceptance sampling plan by attributes is used. Next, non-parametric and parametric methods are introduced as ways to determine the storage reliability of ammunition. Among non-parametric methods, Kaplan-Meier method can be used since it can also handle censored data. Among parametric methods, Weibull distribution can be used to determine the storage reliability of ammunition.

• 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.

• 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.

• 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 the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3670-3676
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• 2011

A cell animation is represented by one background cell, and there is much difference of images when its shot is changed. Also, it does not have a lot of colors since people themselves draw it. In order to effectively detect shot transitions of cell animations while fully considering their intrinsic characteristics, in this paper, we propose a animation shot boundary detection algorithm that utilizes color and block-based histograms step by step. The suggested algorithm first converts RGB color space into HSI color one, and coarsely decides if adjacent frames contains a shot transition by performing color difference operation between two images. If they are considered to have a shot transition candidate, we calculate color histograms for 9 sub-regions of the adjacent images and apply weights to them. Finally, we determine whether there is a real shot transition by analyzing the weighted sum of histogram values. In experiments, we show that our method is superior to others.

• Journal of the Korean Statistical Society
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• v.7 no.1
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• pp.61-80
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• 1978

This paper presents general solutions for stochastic square duels with continuous interfiring times and various firing strategies such as standby (S), concentrated (C), seperated (I) and random (R) firings. Analysis of these square duels with negative exponential interfiring times and equivalent values of rates of fire and single shot kill probabilities reveal three important facts: i) Strategy (C) is advantageous against the opponent's strategy (S) and the advantage becomes more pronounced for lower values of single shot kill probabilities. ii) Strategy (I) is always better than strategy (C) no matter which of (C) and (I) the opponent uses and its relative advantege increases to a quarter as single shot kill probabilities increase to one but decreases to zero as they go to zero. iii) However, strategy (I) has no advantage over strategy (C) for small values of single shot kill probabilities. In this paper, square duels with strategies (C) and (I) are based on the assumptions that duelists are homogeneous and both duelists of one side fire simultaneously. The problem of relaxing these assumptions and extension of square ($2 \times 2$) duels to more general ($m \times n) duels are now being investigated.