• International Journal of Highway Engineering
• /
• v.18 no.4
• /
• pp.19-28
• /
• 2016

PURPOSES : Long-life asphalt pavements are used widely in developed countries. In order to be able to devise an effective maintenance strategy for such pavements, in this study, we evaluated the performance of the long-life asphalt pavements constructed along the national highways in South Korea. Further, an economic evaluation of the long-life asphalt pavements was performed based on a life-cycle cost analysis. We aimed to devise a model for evaluating the performance of long-life asphalt pavements using the national highway pavement management system (PMS) database as well as for analyzing the economic feasibility of such pavements, in order to promote their use in South Korea. METHODS : The maintenance history and pavement performance data were obtained from the national highway PMS database. The pavement performances for a total of 292 sections of 10 lanes (5 northbound lanes and 5 eastbound lanes) of national highways were used in this study. Models to predict the performances of hot mix asphalt (HMA) and long-life asphalt pavements under two distinct traffic conditions were developed using a simple regression method. Further, the economic feasibility of long-life asphalt pavements was evaluated using the Korea Pavement Management System (KoPMS). RESULTS : We developed service-life prediction models based on the traffic volume and the equivalent of single-axle load and found that long-life asphalt pavements have service lives 50% longer than those of HMA pavements. Further, the results of the economic analysis showed that long-life asphalt pavements are superior in terms of various economic indexes, including user cost, delay cost, total cost, and user benefits, even though their maintenance cost is higher than that of HMA pavements. A comparison of the economic feasibilities of the various groups showed that group A is superior to HMA pavements in all aspects except in terms of the maintenance criterion (crack 20% or higher) as per the NPV index. However, the long-life asphalt pavements in group B were superior in terms of the maintenance criterion (crack 25% or higher) regardless of the economic feasibility. CONCLUSIONS : The service life of long-life asphalt pavements was found to be approximately 50% longer than that of HMA pavements, regardless of the traffic volume characteristics. The economic feasibility of long-life asphalt pavements was evaluated based on the KoPMS. The results of the economic analysis were the following: long-life asphalt pavements are exceptional in terms of almost all factors, such as user cost, delay cost, total cost, and user benefit; however, the exception is the maintenance cost. Further, the economic feasibility of the long-life asphalt pavements in group B was found to be better than that of the HMA pavements (crack 25% or higher).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6A
• /
• pp.965-976
• /
• 2006

A realistic lifetime seismic-reliability based approach is unavoidable to perform Life-Cycle Cost (LCC)-effective optimum design, maintenance, and retrofitting of structures against seismic risk. So far, though a number of researchers have proposed the LCC-based seismic design and retrofitting methodologies, most researchers have only focused on the methodological point. Accordingly, in most works, they have not been quantitatively considered critical factors such as the effects of seismic retrofit, maintenance, and environmental stressors on lifetime seismic reliability assessment of deteriorating structures. Thus, in this study, a systemic lifetime seismic reliability analysis methodology is proposed and a program HPYER-DRAIN2DX-DS is developed to perform the desired lifetime seismic reliability analysis. To demonstrate the applicability of the program, it is applied to an example bridge with or without seismic retrofit and maintenance strategies. From the numerical investigation, it may be positively stated that HYPER-DRAIN2DX-DS can be utilized as a useful numerical tool for LCC-effective optimum seismic design, maintenance, and retrofitting of bridges.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.133-138
• /
• 1997

For a long time, a number of alarm processing techniques have been researched to reduce the number of actuated alarms for operators to deal with effectively during the abnormal as well as the normal conditions. However, the strategy that the only systems with a few clear technologies should be used as a part of an alarm annunciation system has been adopted considering the effectiveness and the reliability in actual alarm processing systems. Therefore, alarm processing systems have difficult knowledge-base maintenance problems and limited expansion or enhancement defects. To solve these shortcomings, the integrated knowledge-base which can express the general information related to all the alarm processing techniques is proposed and its management tool, Knowledge Input Tool for Alarm (KIT-A) which can handle the data of the knowledge-base efficiently is developed. Since the integrated knowledge-base with KIT-A can manipulate all the alarm information without the modification of alarm processing system itself, it is expected to considerably advance the overall capability of maintenance and enhancement of the alarm processing systems.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.04a
• /
• pp.16-32
• /
• 2000

This paper aims at exploring financing methods for port development in response to unification of South and North Korea. In so doing, methods of port financing employed by major countries have been enumerated. Major financing sources for the two Korea, among others, taxes, public bond, public administration fund, establishment of harbour maintenance tax, port development tax, port development fund, Civil Economic Cooperation Fund of South and North Korea, and Fund for Port Development of North Korea and, fund for cooperation of South and North Korea, Economic Development Cooperation Fund, borrowing of foreign capital, project financing, domestic civil capital investment, foreign capital investment, application of cross-subsidization principle, etc. were suggested.

• Structural Monitoring and Maintenance
• /
• v.7 no.1
• /
• pp.1-12
• /
• 2020

Railway tracks are the direct supporting structures of the trains, which are vulnerable to produce large deformation under the temperature stress or subgrade settlement. The health status of track is critical, and the track should be routinely monitored to improve safety, lower the risk of excess deformation and provide reliable maintenance strategy. In this paper, the distributed optical fiber sensor was proposed to monitor the continuous deformation of the track. In order to validate the feasibility of the monitoring method, two deformation monitoring tests on one steel rail model in laboratory and on one real railway tack in outdoor were conducted respectively. In the model test, the working conditions of simply supported beam and continuous beam in the rail model under several concentrated loads were set to simulate different stress conditions of the real rail, respectively. In order to evaluate the monitoring accuracy, one distributed optical fiber sensor and one fiber Bragg grating (FBG) sensor were installed on the lower surface of the rail model, the strain measured by FBG sensor and the strain calculated from FEA were taken as measurement references. The model test results show that the strain measured by distributed optical fiber sensor has a good agreement with those measured by FBG sensor and FEA. In the outdoor test, the real track suffered from displacement and temperature loads. The distributed optical fiber sensor installed on the rail can monitor the corresponding strain and temperature with a good accuracy.

• The Journal of Information Systems
• /
• v.28 no.4
• /
• pp.27-47
• /
• 2019

Purpose The study examined the key factors influencing the formation mechanism of SNS addiction. Based on the use and gratification theory, we considered relationship maintenance, perceived enjoyment, and self-expression as main desires to induce SNS addiction. The characteristics of SNS users were also considered as major factors affecting SNS addiction. In particular, self-control and subjective well-beings were considered to be prevention factors that could reduce SNS addiction, while SNS relational intimacy was considered to be a facilitator that would increase SNS addiction. Design/Methodology/Approach A structural equation modeling (SEM) method was used to test the theoretical framework based on a sample of 224 Facebook users who have used it more than 6 months. Confirmation factor analysis was conducted to check the reliability, convergent validity, and discriminant validity. Findings Relationship maintenance had a significant effect on self-disclosure intention and SNS addiction, respectively. Perceived enjoyment was significantly related to self-disclosure intention, while it was insignificantly associated with SNS addiction. However, self-expression was not significantly related to both self-disclosure intention and SNS addiction. Consistent with our expectations, both self-control and subjective well-beings had negative effects on SNS addiction. The analysis results found that SNS relational intimacy was positively related to SNS addiction.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2010.05a
• /
• pp.207-208
• /
• 2010

The building that supply tidal and splash zone was constructed near Seamangeum Gate Bridge. The specimens that will be tested for maintenance of gate bridge were exposed on the tidal and splash zone, totally about 650. The characteristics of strength, salt penetration profile, field application of surface repair material and section recover material will be acquired by periodical test. The program was developed to obtain optimal maintenance strategy of gate bridge as a marine concrete structure and to deposit experimental data, lab. test result, field test result, on its D/B. On this paper, the comparison of concrete and recover material in the salt penetration characteristics was expressed. The quantitative analysis of salt contents in concrete surface was most important so the improvement for the machine of gathering power of concrete and the apparatus of measuring chloride contents was proceeded at this time. The two conclusions were summarized like as - The resistance of chloride attack of concrete was appeared 2.5 times bigger than that of recover material - The resistance of chloride attack of polymer series was appeared more higher than that of others.

• Clinical and Experimental Pediatrics
• /
• v.54 no.9
• /
• pp.363-367
• /
• 2011

Central venous catheters (CVCs) are regularly used in intensive care units, and catheter-related bloodstream infection (CRBSI) remains a leading cause of healthcare-associated infections, particularly in preterm infants. Increased survival rate of extremely-low-birth-weight infants can be partly attributed to routine practice of CVC placement. The most common types of CVCs used in neonatal intensive care units (NICUs) include umbilical venous catheters, peripherally inserted central catheters, and tunneled catheters. CRBSI is defined as a laboratory-confirmed bloodstream infection (BSI) with either a positive catheter tip culture or a positive blood culture drawn from the CVC. BSIs most frequently result from pathogens such as gram-positive cocci, coagulase-negative staphylococci, and sometimes gram-negative organisms. CRBSIs are usually associated with several risk factors, including prolonged catheter placement, femoral access, low birth weight, and young gestational age. Most NICUs have a strategy for catheter insertion and maintenance designed to decrease CRBSIs. Specific interventions slightly differ between NICUs, particularly with regard to the types of disinfectants used for hand hygiene and appropriate skin care for the infant. In conclusion, infection rates can be reduced by the application of strict protocols for the placement and maintenance of CVCs and the education of NICU physicians and nurses.

• Structural Monitoring and Maintenance
• /
• v.3 no.3
• /
• pp.233-257
• /
• 2016

This paper provides an overview on development of long-span bridges monitoring in Japan, with emphasis on monitoring strategies, types of monitoring system, and effective utilization of monitoring data. Because of severe environment condition such as high seismic activity and strong wind, bridge monitoring systems in Japan historically put more emphasis on structural evaluation against extreme events. Monitoring data were used to verify design assumptions, update specifications, and facilitate the efficacy of vibration control system. These were among the first objectives of instrumentation of long-span bridges in a framework of monitoring system in Japan. Later, monitoring systems were also utilized to evaluate structural performance under various environment and loading conditions, and to detect the possible structural deterioration over the age of structures. Monitoring systems are also employed as the basis of investigation and decision making for structural repair and/or retrofit when required. More recent interest has been to further extend application of monitoring to facilitate operation and maintenance, through rationalization of risk and asset management by utilizing monitoring data. The paper describes strategies and several examples of monitoring system and lessons learned from structural monitoring of long-span bridges in Japan.

• Journal of Information Technology Applications and Management
• /
• v.20 no.2
• /
• pp.69-87
• /
• 2013

The expanded spiral model in this paper consists of five processes of architecture design, architectural construction, architectural maintenance, operation, and architectural management. The former four processes are executed alternatively, while the latter architectural management process is executed continuously interacting with the other processes during the whole life cycle of the system. The expanded spiral model provides a conceptual framework to sort discussions of architectural degeneration into those of product-oriented processes and those of management processes, making it possible to incorporate the models and body of knowledge about project and program management especially those of Project Management Institute, into discussions of architectural degeneration. A good architecture decomposes the software-intensive system into components mutually interacting in a well-formed structure. The architecture design process and the architectural construction process together create the object system with well-designed architecture. The architectural maintenance process prevents the implemented architecture deviate from the designed architecture. The architectural management process monitors the changes of requirements including architecturally significant requirements, supports the other processes to be executed reflecting various perspectives of stake-holders, and creates and documents the reasons of architectural decisions, which is considered as a key element of the architecture.