• 한국산학기술학회논문지
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• 제21권1호
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• pp.628-633
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• 2020

본 논문에서는 일회성 시스템이 장기 저장되는 동안 수명을 관리하기 위한 프로그램에 대해 연구하였다. 일회성 시스템은 주로 장기간 저장 또는 비운용 상태로 유지되다 임무수행시 일회성으로 운용되는 특징이 있으며, 일회성에 해당하는 기능은 주로 화약과 같은 시효성 품목을 통해 발휘된다. 이러한 시효성 품목은 저장 기간이 경과됨에 따라 성능과 특성이 변화하는 품목으로서 장기 저장간 정상 상태를 유지하기 위한 수명 관리가 매우 중요하며, 체계적인 수명 관리를 위해서는 관리 기준 설정이 필요하다. 수명 관리 기준과 현재 신뢰도를 비교하여 수명연장을 결정하며, 차기 수명평가 시기를 결정하는 방법을 지수분포와 와이블분포별로 제시한다. 수명평가 결과 시험데이터를 지속적으로 누적하며 수명분포의 모수를 최신화하고 신뢰도 변화를 확인하여, 수명을 연장하거나 만료를 판정한다. 또한, 일회성 시스템인 K000 신관의 ASRP 시험데이터를 활용하여 제안된 수명 관리 프로그램에 따라 수명 관리가 어떻게 이뤄지게 되는지 적용 가능성을 확인하였다.

• 한국지반환경공학회 논문집
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• 제13권4호
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• pp.77-91
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• 2012

최근 우리나라는 국토의 고도 이용과 지역 간의 균형발전을 도모하기 위한 목적으로 택지 및 단지, 도로, 항만 및 공항 등의 건설이 증가하고 있는 추세이다. 현재도 많은 공사들이 연약한 지반에서 실시되고 있다. 이로 인해 건설현장에서 지반의 장기침하, 파괴, 부등침하, 국지적인 구조물 손상 등의 공학적인 문제들이 지속적으로 보고되고 있다. 특히, 연약지반이 비교적 두껍게 발달한 서 남해안 지역과 내륙지역의 연약지반 위에 축조되는 각종 구조물, 도로 등의 경우 필연적으로 하중에 의한 지반의 장기침하가 발생하게 된다. 따라서, 본 연구에서는 기존의 장기침하량 예측기법들인 쌍곡선법, 호시노법, $\sqrt{S}$법, 아사오카법 등의 지역별 적정 분석기법을 검토하는 한편, 일반화된 산정식의 도출을 통한 새로운 예측기법에 대한 연구를 수행하여 토질특성 및 시공조건에 대한 상관관계를 분석하고 장기적인 침하특성과의 연관계수를 도출하였다. 수식의 검증을 위해 16개 지역의 계측자료와 수치해석 결과를 비교 및 분석을 실시하였다.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.18-29
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• 2019

In the field of Human-Computer Interaction design, persuasive design has gradually been applied to the system development and design process, especially for mobile application design. However, most mobile applications have hitherto a very short using lifecycle. Especially, design features with long-term persuasive effectiveness remain to be further researched and developed. In this study, we focused on investigating and identifying the durative persuasive design characteristics through a data mining process and evaluating the durative effectiveness through a long-term observation process. Total five hundred healthcare-related mobile applications were selected from Apple iTunes Store and a mixed method was conducted to extract the most common persuasive design characteristics. Based on the results of extraction, a representative healthcare-related mobile application was selected as experimental subject. Total one hundred and twenty participants were observed during a six-months experiment and the monitoring data of app usage of all participants was collected once a week. According to the evaluation model for behavior change identification process, participants with habit formation features were proved to have a significant long-term perception level for ten persuasive design characteristics. Further interview research was performed to investigate the participant's long-term perceptions on those characteristics for the purpose of identifying the durative persuasions. The results indicated that a long-term durative effectiveness can be observed and healthcare-related apps designed with those characteristics could have durative effectiveness. This study may contribute to the improvement of future mobile application designs in user experience and durative persuasion, as well as bringing future benefits for both mobile application developers and users.

• 한국CDE학회논문집
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• 제14권6호
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• pp.424-433
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• 2009

In order to improve productivity and efficiency of ship production process, production technology converged with Information Technology can be considered. Mid-term scheduling based on long-term schedule of ship building and execution planning based on short-term production schedule have an important role in ship production processes and techniques. However, data used in the scheduling are from the experiences of the past, cognitive, and often inaccurate, moreover the updates of the data by formatted documents are not being performed efficiently. This paper designs the tracking and monitoring system for the curved plates forming process with shop level. At first step to it, we redefine and analyze the curved plates forming process by using SysML. From the definition and analysis of the curved plates forming process, we design the system with respect to operational view considering operational environment and interactions between systems included and scenario about operation, and with respect to system view considering functionalities and interfaces of the system. In order to study the feasibility of the system designed, a prototype of the system has been implemented with 13.56 MHz RHD hardware and application software.

• Smart Structures and Systems
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• 제17권6호
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• pp.981-994
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• 2016

Two field research stations based upon atmospheric corrosivity monitoring combined with reinforced concrete corrosion rate sensors have been established in Kuwait. This was established for the purpose of remote monitoring of building materials performance for concrete under Kuwait atmospheric environment. The two field research sites for concrete have been based upon an outcome from a research investigation intended for monitoring the atmospheric corrosivity from weathering station distributed in eight areas, and in different regions in Kuwait. Data on corrosivity measurements are essential for the development of specification of an optimized corrosion resistance system for reinforced concrete manufactured products. This study aims to optimize, characterize, and utilize long-term concrete structural health monitoring through on line corrosion measurement and to determine the feasibility and viability of the integrated anode ladder corrosion sensors embedded in concrete. The atmospheric corrosivity categories supported with GSM remote data acquisition system from eight corrosion monitoring stations at different regions in Kuwait are being classified according to standard ISO 9223. The two nominated field sites where based upon time of wetness and bimetallic corrosion rate from atmospheric data where metals and rebar's concrete are likely to be used. Eight concrete blocks with embeddable anodic ladder corrosion sensors were placed in the atmospheric zone adjacent to the sea shore at KISR site. The anodic ladder corrosion rate sensors for concrete were installed to provide an early warning system on prediction of the corrosion propagation and on developing new insights on the long-term durability performance and repair of concrete structures to lower labor cost. The results show the atmospheric corrosivity data of the environment and the feasibility of data retrieval of the corrosion potential of concrete from the embeddable sets of anodic ladder corrosion sensors.

• Smart Structures and Systems
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• 제29권1호
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• pp.167-179
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• 2022

This article develops a long-term condition assessment method for stay cables in cable stayed bridges using the monitored cable tension forces under operational condition. Based on the concept of influence surface, the matched cable tension ratio of two cables located at the same side (either in the upstream side or downstream side) is theoretically proven to be related to the condition of stay cables and independent of the positions of vehicles on the bridge. A sensor grouping scheme is designed to ensure that reliable damage detection result can be obtained even when sensor fault occurs in the neighbor of the damaged cable. Cable forces measured from an in-service cable-stayed bridge in China are used to demonstrate the accuracy and effectiveness of the proposed method. Damage detection results show that the proposed approach is sensitive to the rupture of wire damage in a specific cable and is robust to environmental effects, measurement noise, sensor fault and different traffic patterns. Using the damage sensitive feature in the proposed approach, the metrics such as accuracy, precision, recall and F1 score, which are used to evaluate the performance of damage detection, are 97.97%, 95.08%, 100% and 97.48%, respectively. These results indicate that the proposed approach can reliably detect the damage in stay cables. In addition, the proposed approach is efficient and promising with applications to the field monitoring of cables in cable-stayed bridges.

• 한국농공학회논문집
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• 제65권2호
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• pp.35-45
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• 2023

The DOR (Drainage outlet raising) in the paddy field has been suggested as one of the most important best management practices for the TMDL (Total maximum daily load) management in the technical guidelines by the NIER (National institute of environmental research). However, this method is underestimated and is not well adopted by local governments for the TMDL. The purpose of this study is to evaluate the unit load reduction equation according to the application of DOR in order to expand this equation. The original equation in the guideline was derived using the HSPF (Hydrological Simulation Program-Fortran) model for 1 year in Changnyeong. We analyzed the reduction effect of the original equation application by collecting additional long-term monitoring data from the Buan, Icheon, Iksan, and Jeonju. When comparing the reduction loads between the original equation and monitoring results, the evaluation results of the original equation were 11% of the monitoring analysis results, which was underestimated. This means that the original equation needs to be improved. For assessing the equation, the HSPF Paddy-RCH model was established according to the NI ER guideline and evaluated for applicability. The performance results of the model showed a reasonable range by the statistical criteria. Modified equations 1 and 2 were proposed based on the monitoring and modeling results. Modified equation 1 was the method of modifying the original equation's main factors, and modified equation 2 was the method of applying the non-point pollution reduction efficiency according to the rainfall class using the long-term modeling results. At the level of 58.6~64.6% of monitoring data, the difference between them could be further reduced compared to the original equation. The suggested approach will be more reasonable and practicable for decision-makers and will contribute to the TMDL management plans.

• Smart Structures and Systems
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• 제22권1호
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• pp.57-70
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• 2018

For the long-term structural health monitoring of civil structures, the effect of ambient temperature variation has been regarded as one of the critical issues. In this study, a principal component analysis (PCA)-based algorithm is proposed to filter out temperature effects on electromechanical impedance (EMI) monitoring of prestressed tendon anchorages. Firstly, the EMI monitoring via a piezoelectric interface device is described for prestress-loss detection in the tendon anchorage system. Secondly, the PCA-based temperature filtering algorithm tailored to the EMI monitoring of the prestressed tendon anchorage is outlined. The proposed algorithm utilizes the damage-sensitive features obtained from sub-ranges of the EMI data to establish the PCA-based filter model. Finally, the feasibility of the PCA-based algorithm is experimentally evaluated by distinguishing temperature changes from prestress-loss events in a prestressed concrete girder. The accuracy of the prestress-loss detection results is discussed with respect to the EMI features before and after the temperature filtering.

• 한국해양공학회지
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• 제18권1호
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• pp.10-15
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• 2004

For effective conservation of the oceans and harbors, long-term and systematic development of the ocean and harbor monitoring system is essential. A monitoring system capable of real-time and accurate data acquisition is necessary for dealing with the level of contamination by situations, such as red tide and foods. This paper introduces an effective and economical real-time harbor environmental monitoring system that utilizes PCS wireless data communication technology. The monitoring system has various functions, such as multiple communication, TCP/IP protocol for wireless internet access, system time synchronization, and bi-directional communication between the measuring device and the server. The system has been implemented at Shinseondae harbor pier in Busan to validate the system's stability and effectiveness in data acquisition. The acquired real-time ocean and harbor environmental data is expected to have a large effect, when shared with the public through the Internet.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.63-68
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• 2003

For effective conservation of ocean and harbor, long-term and systematic development of the ocean and harbor monitoring system is essential. The monitoring system capable of real-time and accurate data acquisition is necessary for dealing with contamination such as red tide and the flood. This paper introduces the effective and economical real-time harbor environmental monitoring system that utilizes PCS wireless data communication technology. The monitoring system has various functions such as multiple communication, TCP/IP protocol for wireless internet access, system time synchronization, bi-directional communication between the measuring device and the server. The system has been implemented at Shinseondae harbor pier in Busan to validate the systems stability and effectiveness in data acquisition. The acquired real-time ocean and harbor environmental data is expected to have a large effect, when shared by public through internet.