• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.765-778
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• 2008

Performance Profiles are essential to predict the performance variation over time for the bridge management system (BMS) based on risk management. In general, condition profiles based on experts opinion and/or visual inspection records have been used widely because obtaining profiles based on real performance is not easy. However, those condition profiles usually don't give a good consistency to the safety of bridges, causing practical problems for the effective bridge management. The accuracy of performance evaluation is directly related to the accuracy of BMS. The reliability of the evaluation is important to produce the optimal solution for distributing maintenance budget reasonably. However, conventional methods of bridge assessment are not suitable for a more sophisticated decision making procedure. In this study, a method to compute quantitative performance profiles has been proposed to overcome the limitations of those conventional models. In Bridge Management Systems, the main role of performance profiles is to compute and predict the performance of bridges subject to lifetime activities with uncertainty. Therefore, the computation time for obtaining an optimal maintenance scenario is closely related to the efficiency of the performance profile. In this study, the Response Surface Method (RSM) based on independent and important design variables is developed for the rapid computation. Steel box bridges have been investigated because the number of independent design variables can be reduced significantly due to the high dependency between design variables.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.1
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• pp.73-80
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• 2018

In motorway traffic flow control, the conventional way based on real-time response has been changed into advanced way based on proactive response. Future traffic conditions over multiple time intervals are crucial input data for advanced motorway traffic flow control. It is necessary to overcome the uncertainty of the future state in order for forecasting multiple-period traffic volumes, as the number of uncertainty concurrently increase when the forecasting horizon expands. In this vein, multi-interval forecasting of traffic volumes requires a viable approach to conquer future uncertainties successfully. In this paper, a forecasting model is proposed which effectively addresses the uncertainties of future state based on the behaviors of temporal evolution of traffic volume states that intrinsically exits in the big past data. The model selects the past states from the big past data based on the state evolution of current traffic volumes, and then the selected past states are employed for estimating future states. The model was also designed to be suitable for data management systems in practice. Test results demonstrated that the model can effectively overcome the uncertainties over multiple time periods and can generate very reliable predictions in term of prediction accuracy. Hence, it is indicated that the model can be mounted and utilized on advanced data management systems.

• Culinary science and hospitality research
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• v.19 no.4
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• pp.161-175
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• 2013

This study investigates the impact of the attributes of the eco-friendly agricultural products traceability system on perceived value and behavioral intention. Empirical subjects are those who live in Seoul and Gyeonggi province, over the age of 20 and have experience of buying eco-friendly agricultural products though department stores, discount stores and specialized eco-friendly product stores. After distributing 550 copies of questionnaire from April 10th, 2013 to May 9th, 2013, 470 copies(85.5%) are used for a final statistical analysis of the survey after excluding the copies with biased opinions or missing values. The results of this study show sufficient theoretical base for future research by verifying a causal relationships between the attributes of eco-friendly agricultural products traceability system such as reliability, safety and innovation, and consumers' perceived value and behavioral intention. Therefore, producers should correctly record producing history base so that consumers can continue to use the system. The traceability system can not only satisfy consumers by enhancing transparent management and producing systems for eco-friendly products but also guarantee us to eat all products we get without worries.

• KAPE Magazine
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• s.250
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• pp.15-17
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• 2017

• The Korean Journal of Applied Statistics
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• v.28 no.4
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• pp.721-739
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• 2015

The importance of the old age income security will increase for an aging society due to the deepening income polarization. The National Pension(NP) is a representative Social Security scheme in charge of old age income security as well as income redistribution for the insured. Studies by Kim (2002), Kim et al. (2003), and Hong (2013) have reported the possibility of unsatisfactory income redistribution of the NP. Recently Choi (2015) attributed those results to an unnoticed defect in the benefit formula. This study is a test for the unsatisfactory income redistribution of the current National Pension using early participants who have now become pensioners. The method aggregates cohorts and combines individual history data before the year 2013 and the results of the actuarial projection model of the 2013 after the year 2014. The results are divided by measures taken. The redistribution is obviously progressive by the income replacement rate; however, it is significantly regressive when measured by the net benefit theoretically as more plausible. Considering the effect of differing lifetime contribution year among income classes, the regressive redistribution will prevail more in the future pensioners.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2007.10a
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• pp.265-270
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• 2007

국가기준점은 측량을 위한 주요 시설물로서 관리가 매우 중요하다. 그러나 국가기준점이 설치되어 있는 환경은 측량을 위한 시야 확보가 필요하기 때문에 삼각점의 경우 산 정상이나 인근 기준점과 시통이 가능한 위치에 설치하며, 수준점의 경우 도로변이나 하천변에 설치한다. 국가기준점은 화강암으로 된 표석 형태로 설치되기 때문에 이렇게 외부환경에 노출될 경우 자연 풍화, 인위적인 훼손, 파손 등이 발생할 수 있다. 이러한 현황 파악을 위하여 주기적인 방문관리가 필요하다. 그러나 전국적으로 약 22,000개 가량 설치되어 관리가 어려운 실정이다. 본 연구에서는 국가기준점 관리의 효율성을 높이고 기준점 정책 수립을 위한 통계자료수집을 위한 국가기준점 모니터링 시스템을 개발하였다.본 시스템은RFID가 부착된 국가기준점을 사용할 경우 RFID를 인식하는 단말기는 실시간으로 CDMA 망을 이용하여 모니터링 시스템에 정보를 전송하고, 웹 시스템 상에서 실시간으로 현재 사용중인 기준점이 표시된다. 사용중인 기준점의 사용용도 및 사용자의 현황도 화면에 표시된다. 이러한 정보는 이력관리가 되며, 사용 및 관리에 관한 이력정보 보고서, 기준점별 사용 빈도 및 사용 목적별 빈도 등이 저장되어 기준점 설치, 관리 대상 기준점 선정 등을 위한 기준점 정책 수립을 위한 통계자료를 생산할 수 있다. 이러한 시스템 개발을 통하여 실시간 기준점 모니터링이 가능하며, 관리대상 기준점 선정, 전산화된 이력관리 구현 등으로 인하여 관리비용을 절감하고, 관리인력을 최소화 하는 효율적인 기준점 관리가 가능하게 될 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1360-1368
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• 2010

Recently, as the development of Radio Frequency Identification (RFID) technology becomes active, the demand for services which can electronically manage the history and location information of major trees, including trees for cultural heritage restoration and nurse trees, has been increased. This information has been managed by separated drawings and documents or storing its information into PDAs and then structuring data files through input and computation. But, these methods imply limitations in terms of its extensibility and scalability. This paper has designed and implemented an RFID based Tree History Information System (THIS) for cultural heritage restoration. The purpose of the proposed system is to support to be able to effectively and consistently manage historical information of major trees and improve working processes by implementing mobile RFID services through wireless Internet or Local Area Network (LAN) as mobile communication networks. Through implementation, it is confirmed that the proposed system can manage the historical information of major trees more effectively than conventional methods and also improve previous field working conditions.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.417-429
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• 2015

Evaluation of traffic data quality is a backbone of better traffic information and management systems because it directly affects the reliability of traffic information. This study developed an integrated index for evaluating the quality of archived intelligent transportation systems (ITS) data. Two novel indices including spatio-temporal consistency and severity of missing data were devised and integrated with existing indices such as availability and completeness. An evaluation framework was proposed based on the developed integrated index. Both analytical hierarchical analysis (AHP) technique and entropy method were adopted to derive mixed weighting values to be used for the integrated index. It is expected that the proposed methodology would be effectively used in enhancing the quality of traffic data as a part of traffic information system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.3
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• pp.174-182
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• 2007

There are not many studies on the maintenance and replacement for the ITS equipments. Most of ITS center has no comprehensive regulation on the equipment replacement. This study was focusing on estimation of equipment replacement period and the number of spare parts in stock using the actual failure data of Road Side Equipment (RSE) by Dedicated Short Range Communication (DSRC). The failure data showed a type of bath-tub curves. The data, however, did not fit to any probability distribution curve, which means that the preventive replacement cannot be strongly applied for the RSE. In the aspect of practical strategy, this study suggest that repairing cost and failure frequency be used for decision of replacement of RSE after the 1 or 2 year warrant period. The future study needs to include more RSE failure data as well as other equipments of the ITS.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.5-14
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• 2014

Most of slope failures have taken place between June and September in Korea, which cause a considerable damage to society. Rainfall intensity and duration are very significant triggering factors for landslide. In this paper, landslide-triggering rainfall threshold consisting of rainfall intensity-duration (I-D) was proposed. For this study, total 255 landslides were collected in landslide inventory during 1999 to 2012 from NDMI (National Disaster Management Institute), various reports, newspapers and field survey. And most of the required rainfall data were collected from KMA (Korea Meteorological Administration). The collected landslides were classified into three categories: debris flow, shallow landslide and unconfirmed. A rainfall threshold was proposed based on landslide type using statistical method such as quantile-regression method. Its validation was carried out based on 2013 landslide database. The proposed rainfall threshold was also compared with previous rainfall thresholds. The proposed landslide-triggering rainfall thresholds could be used in landslide early warning system in Korea.