• 한국군사과학기술학회지
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• 제12권6호
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• pp.719-726
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• 2009

A delay system in fuze for high explosive shell is an important safety device, but failure in the delay system usually causes failure of the shell. Root-cause analysis of failure in the delay system is required since failure in over 10-years stored delay system recently occurs. In this paper, failure in the delay system was reproduced experimentally to examine aged characteristics of the delay system, and the failed delay system shows the same characteristics as ones of failed delay systems in field. Based on the reproduced experiments, accelerated life testings and the data analysis of failure times of delay systems were performed to predict the storage lifetime.

• 한국경영과학회지
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• 제38권3호
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• pp.37-50
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• 2013

The purpose of this study is to determine the indicators and the criteria to classify types of train delays of high-speed rail in South Korea. Types of train delays have divided into the chronic delays and the knock-on delays. The Indicators based on relevance, reliability, and comparability were selected with arrival delay rate of over five minutes, median of arrival delays of preceding train and following train, knock-on delay rate of over five minutes, correlation of delay between preceding train and following train on intermediate and last stations, average train headway, average number of passengers per train, and average seat usages. Types of train delays were separated using the Ward's hierarchical cluster analysis. The criteria for classification of train delay were presented by the Fisher's linear discriminant. The analysis on the situational characteristics of train delays is as follows. If the train headway in last station is short, the probability of chronic delay is high. If the planned running times of train is short, the seriousness of chronic delay is high. The important causes of train delays are short headway of train, shortly planned running times, delays of preceding train, and the excessive number of passengers per train.

• 한국산업융합학회 논문집
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• 제20권3호
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• pp.205-212
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• 2017

This paper focuses on worst-case delay analysis of the time-triggered IEEE 802.15.4 protocol to satisfy the industrial quality-of-service (QoS) performance. The IEEE 802.15.4 protocol is considered to be unsuitable for industrial networks because its medium access control method is contention-based CSMA/CA, which exhibits unstable performance with an unbounded delay distribution under heavy traffic. To avoid these limitations, this paper presents a time-triggered version of the nonbeacon-enabled network of IEEE 802.15.4 that relies on a time division multiplexing access (TDMA) method implemented in the application layer without any modification of specification. The timing analysis of this time-triggered IEEE 802.15.4 was executed, and the worst-case transmission delay was calculated. Based on this analysis, the time-triggered IEEE 802.15.4 is a promising alternative for wireless industrial networking.

• 대한토목학회논문집
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• 제29권5D호
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• pp.563-570
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• 2009

본 연구는 신호교차로 분석시 추가지체 산정을 위하여 적용하는 초기 대기차량이 총 지체도에 얼마나 영향을 미치는지 분석하기 위한 목적으로 실시하였다. 평균교차로 지체시간을 측정하기위하여 통과차량과 대기행렬이 측정되었다. 분석결과, 시험차량의 평균 지체도가 60초/대 미만 일 경우에는 세가지 지체도 산정방법이 모두 유사한 것으로 분석되었으나, 60~70초/대는 초기 대기차량을 적용한 지체도만 시험차량의 평균지체도와 유사한 것으로 분석되었다.

• Journal of Mechanical Science and Technology
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• 제20권8호
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• pp.1195-1208
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• 2006

This paper aims at presenting robustness analysis under the uncertainties of the time delay and plant parameters in symmetrically coupled dynamic systems connected through network having time delay. The delay-involved closed loop characteristic function is mathematically formulated, incorporated with active synchronization control. And the robust stability of the corresponding system is analyzed by investigating the formation of characteristic equation containing second- order terms of uncertainty variables representing delay and plant dynamics mismatches. For the two individual types of uncertainties, we elucidate details of how to compute the bounds and what they imply physically. To support the validity of the mathematical claims, numerical examples and simulations are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.677-680
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• 2003

In this paper, the analysis of practical end-to-end delay in worst case is performed for distributed control system considering the implementation of the system. The control system delay is composed of the delay caused by multi-task scheduling of operating system, the delay caused by network communication, and the delay caused by the asynchronous between them. Through simulation tests based on CAN(Controller Area Network), the proposed end-to-end delay in worst case is validated. Additionally, online clock synchronization algorithm is proposed here for the control system. Through another simulation test, the online algorithm is proved to have better performance than offline one in the view of network bandwidth utilization.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.271-278
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• 2021

In this paper, a tropospheric delay error was calculated by using meteorological data collect from weather station and Saastamoinen model, and an empirical variogram of the tropospheric delay in the Korean peninsula was estimated. In order to estimate the empirical variogram of the tropospheric delay according to weather condition, sunny day, rainy day, and typhoon day were selected as analysis days. Analysis results show that a maximum correlation range of the empirical variogram on sunny day was about 560 km because there is overall trend of the tropospheric delay. On the other hand, the maximum correlation range of the empirical variogram on rainy was about 150 km because the regional variation was large. Although there is regional variation when the typhoon exists, there is a trend of the tropospheric delay due to a movement of the typhoon. Therefore, the maximum correlation range of the empirical variogram on typhoon day was about 280 km which is between sunny and rainy day.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.213-221
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• 2022

Defects are the risk factors in the construction process of buildings. They cause damage, delaying the construction duration. They especially cause adverse effects on the top-down construction method. This study analyzed the degree of construction delay induced by each work type, focusing on defects in the top-down method. Then, we derived construction delay induction coefficient from different work types in order by using the severity of construction delay per defect and the occurrence probability of defect; this assessment model measures the impact of defects on construction delay for each work type. Furthermore, by comparing each work type based on the defect frequency and the construction delay induction coefficient, we found work types that need to be administered attentively. We identified that plastering work was easy to overlook, requiring caution in defect management. This study provides an efficient defect management system suitable for the buildings that are built using the top-down construction method.

• Journal of information and communication convergence engineering
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• 제3권3호
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• pp.119-121
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• 2005

This paper aims to estimate the delay time of multiple signals in a multi-path environment. It also seeks to carry out a comparative analysis with the existing delay time under the proposed algorithm to develop a new algorithm that applies the space average method in a MUSIC algorithm. Unlike the existing delay time estimation algorithm, the developed algorithm was able to estimate the delay time in 5ns low. Therefore, the algorithm proposed in this paper improved the existing delay time estimated algorithm.

• 복식
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• 제45권
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• pp.71-84
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• 1999

This study was to identify the dimensions of consumer's purchasing motives and purchasing delay reasons toward casual hanbok. Other objective was to examine relationship between these variables and future purchasing intention. Th 22 purchasing motive questions and 19 purchasing delay reasons were selected through the result of self-questionnaire analysis. 302 purchaser and 297 consumers who delay for particular reasons in Pusan responsed to the second questionnaire of purchasing motives and purchasing delay reasons toward casual Hanbok. The results as follows: 1. For factor analysis 22 purchasing motive questions were subjected to the principle component analysis with orthogonal rotation after extraction of 6 major factors. Six dimensions are consciousness of nation goodness of design conformity with fashion charming apperance relaxation fo body and mind nation goodness of design conformity with fashion charming appearance relaxation of body and mind and pursuit of individuality. These factors explained 62.0% of total variables. 2. Consumer's purchasing motives such as consciousness of nation goodness of design charming appearance and relaxation of body and mind has predicting power to the re-purchasing intention of casual hanbok 3. For factor analysis 19 delay reason question were subjected to the principle component analysis with orthogonal rotation after extraction of 5 major factors. Five dimensions are non-fitness for occasion and body shape unsatisfaction with design unsatisfaction with price need of information search for better product and preference for traditional hangok. These factors explained 60.4% of total variables. 4. Delay reasons of unsatisfaction with design and price were positively related to the future purchasing intention. This delay reason is caused by forces external to the consumer and the consumer has engaged in information search. This result explained this type of consumer has the strong future purchasing intention.