• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.53-59
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• 2010

Recently, NDTs (Non-Destructive Techniques) using infrared camera are widely studied for detection of damage and void in RC (reinforced concrete) structures and they are also considered as an effective techniques for maintenance of infrastructures. The temperature on concrete surface depends on material and thermal properties such as specific heat, thermal conductivity, and thermal diffusion coefficient. Different porosity on cement mortar due to different mixture proportions can show different heat behavior in cooling stage. The porosity can affect physical and durability properties like strength and chloride diffusion coefficient as well. In this paper, active thermography which uses flash for heat induction is utilized and thermal characteristics on surface are evaluated. Samples of cement mortar with W/C (water to cement ratio) of 0.55 and 0.65 are prepared and physical properties like porosity, compressive strength, and chloride diffusion coefficient are evaluated. Then infrared thermography technique is carried out in a constant room condition (temperature $20{\sim}22^{\circ}C$ and relative humidity 55-60%). The mortar samples with higher porosity shows higher residual temperature at the cooling stage and also shows reduced critical time which shows constant temperature due to back wall effect. Furthermore, simple equation for critical time of back wall effect is suggested with porosity and experimental constants. These characteristics indicate the applicability of infrared thermography as an NDT for quality assessment of cement based composite like concrete. Physical properties and thermal behavior in cement mortar with different porosity are analyzed in discussed in this paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2529-2539
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• 2013

The Korean construction industry has led the miraculous economic boost of Korea by providing solid domestic infrastructures such as highway, roads, and airports. It also played a critical role in global construction market and eaned more than 500 billions dollars in terms of their accumulated international orders. However, domestic construction market has significantly decreased in recent years due to the domestic political environments and global economic crisis. Therefore, the importance of international construction market cannot be more emphasized to the Korean construction market in order for the sustainable growth. There has been, however, little research in the area of identifying required competency elements for the Korean construction industry to stay successful in the global market. The main purpose of this study is to identify elements of core competency to increase global competitiveness for Korean construction industry. Core global construction competency elements were derived from the internal and external environmental analyses along with the extensive literature review, expert interviews and a survey. This study utilized the Importance-Performance Analysis (IPA) and a gap analysis in providing insights on the status competitiveness of the Korean construction industry in terms of required global core competency elements. The analysis shows that project management and financial management are the main areas for improvements required to engineering contractors while construction contractors need to take a more balanced approach among technical, project management, and financial management in order to increase their global competencies.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.413-420
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• 2016

Seaports are economically significant infrastructures in terms of dealing with more than 90% of the cargo volume in Korea's international trade. Furthermore, investment costs for constructing ports and the impacts of port industry on national competitiveness lead to the necessity for sustainable port operation. However, the earlier studies dealing with competitiveness and sustainability of the port sector focused on its logistical functions related to port size, operational efficiency, etc. Port competitiveness that considers local community and ecological values as well as the expectations and demands of port users is becoming an important issue in order for ports to cope with volatile external environments while maintaining competitiveness. Therefore, it is necessary to identify port performance indicators and measure their performance in terms of the environmental and social perspectives, as well as the economic perspectives, in order to sustain port development and operations. This paper presents findings from case analyses of SuPorts and PPRISM projects that assist European Union (EU) ports to secure sustainable competitiveness while respecting economic, environmental and social interests between ports and local communities. These projects create port performance indicators with balanced views including not only economic value but also environmental and social values. They measure port performance so port operators can implement these sustainable port practices. This study aims to find the critical factors for sustainable port practices by conducting case analyses of SuPorts and PPRISM projects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.4
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• pp.362-369
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• 2014

A railway SCADA system is a control systems that provide the trains with the electricity. A railway SCADA system sends commands to the RTUs(remote terminal unit) and then it gathers status information of the field devices in the RTUs or controls field devices connected with the RTUs. The RTU can controls input output modules directly, gathers the status information of the field devices connected with it, and send the information to the control center. In this way, a railway SCADA system monitors and controls the electricity power for running trains. The cyber attackers may use some vulnerabilities in the railway SCADA system software to attack critical infrastructures. The vulnerabilities might be created in the railway software development process. Therefore it need to detect and remove the vulnerabilities in the control system. In this paper we propose a new control protocol fuzzing method to detect the vulnerabilities in the DNP3 protocol based application running on VxWorks in RTU(Remote Terminal Unit) that is a component of the centralized traffic control system for railway. Debug-channel based fuzzing method is required to obtain process status information from the VxWorks.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.1
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• pp.17-29
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• 2003

This paper preliminarily investigates the effectiveness of various control systems, such as passive, active, semiactive and hybrid control, for seismic protection of cable-stayed bridges by examining the ASCE first generation benchmark problem for a cable-stayed bridge. This benchm.0.00000ark problem considers the cable-stayed bridge that is scheduled for completion in Missouri, USA In 2003. Seismic considerations were strongly considered in the design of this bridge due to location of the bridge and its critical role as a principal crossing of the Mississippi River. Based on detailed drawings of this cable-stayed bridge, a three-dimensional linearized evaluation model has been developed to represent the complex behavior of the bridge. A set of eighteen evaluation criteria has been developed to evaluate the capability of each control system. In this study, four passive control systems, one active control system, two semiactive control systems and three hybrid control systems are considered. Numerical simulation results show that all the control systems are effective in reducing the responses of the benchmark cable-stayed bridge under the historical earthquakes. To get good performance, however, the passive control systems need quite large control forces compared to other control systems. The simulation results also demonstrate that the passive, semiactive and hybrid control systems are robust to the stiffness uncertainty of the structure. Therefore, the semiactive and hybrid control systems are more appropriate in real applications for full-scale civil infrastructures.

• Journal of the Korean Regional Science Association
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• v.15 no.2
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• pp.155-187
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• 1999

The East Asian Region has experienced remarkable economic growth and transformation of interurban networking over the past three decades, and urban competiti veness for a networking hub in this region has become a critical issue confronting cities. Competitiveness of the Seoul capital region for a networking hub in Northeast Asia is outstripped by other competing cities in East Asia, notwithstanding its geo-politically and geo-economically advantageous location in this region. In this paper, we aim to appraise the Seoul capital region's competitiveness in terms of logistics distribution, financial function and logistics distribution, financial function and agglomeration of transnational corporations (especially of RHOs and other managerial functions), and to advance the networking strategies of the region for a Northeast Asia hyb. As a result of analysis, we suggest that the Seoul capital region be developed as a Northeast Asian center for regional headquarters or leading global corporations and financial services for being a strategic nodal point in Northeast Asia in the 21st century. A recent survey shows that where to locate an RHQ is influenced by various factors, such as potential market and manufacturing site in the city's hinterland, quality of life, such things as culture, health, safety, education, a well-educated, English-speaking population, reliable air transport, state-of-the-art communications, and an active policy to offer foreign companies generous incentives. The Seoul capital region, which is located at a strategic nodal point advantageous as a springboard for its Northeast Asian hinterland, cannot meet the other conditions mentioned above. To overcome these drawbacks in attracting transnational capital and to create competitiveness as a strategic hub of RHQs in Northeast Asia, it is urgent to initiate a structural reform of the Korean economy, politics, and overall society, to minimize the regulation of FDI, and to provide various incentives for foreign investment. Moreover, we propose the construction of an 'International Business Town' in the Seoul capital region, as a medium to intermediate these strategies and to shape them in a spatial scale. The projected 'International Business Town(IBT)' will be a 'free city' open to international business in which liberal economic activities are guaranteed by special legislation and administration, infrastructures needed for international and improved accessibility to the airport are furnished, and the preference of foreign high-income investors for cultural and living environment are satisfactorily met. IBT is conspicuously differentiated from a raft of other cities' incentives in that it combines deregulation and incentive programs to attract the investment of transnational capital, with a spatial program of offering an urban environment preferred by the high-income investors for cultural and living environment are satisfactorily met. IBT is conspicuously differentiated from a raft of other cities' incentives in that it combines deregulation and incentive programs to attract the investment of transnational capita, with a spatial program of offering an urban environment preferred by the high-income and managerial class. Furthermore, it can be an excellent way of overcoming the xenophobia that has spread among the Korean population by concentrating foreign businesses and their lifestyles in a specific foreign businesses and their lifestyles in a specific zone. In conclusion, 'International Business Town', in line with other legislative and administrative incentive programs, will function as a driving force to make the Seoul capital regional more competitive as a regional business hub in Northeast Asia.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.465-479
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• 2020

Regardless of the domestic and foreign governments/companies, SOC (Security Operation Center) has operated 24 hours a day for the entire year to ensure the security for their IT infrastructures. However, almost all SOCs have a critical limitation by nature, caused from heavily depending on the manual analysis of human agents with the text-based monitoring architecture. Even though, in order to overcome the drawback, technologies for a comprehensive visualization against complex cyber threats have been studying, most of them are inappropriate for the security monitoring in large-scale networks. In this paper, to solve the problem, we propose a novel visual approach for intuitive threats monitoring b detecting suspicious IP address, which is an ultimate challenge in cyber security monitoring. The approach particularly makes it possible to detect, trace and analysis of suspicious IPs statistically in real-time manner. As a result, the system implemented by the proposed method is suitably applied and utilized to the real-would environment. Moreover, the usability of the approach is verified by successful detecting and analyzing various attack IPs.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.133-143
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• 2023

As drones (also known as UAV) become popular with advanced information and communication technology (ICT), they have been utilized for various fields (agriculture, architecture, and so on). However, malicious attackers with advanced drones may pose a threat to critical national infrastructures. Thus, anti-drone systems have been developed to respond to drone threats. In particular, remote identification data (R-ID)-based UAV detection and identification systems that detect and identify illegal drones with R-ID broadcasted by drones have been developed, and are widely employed worldwide. However, this R-ID-based UAV detection/identification system is vulnerable to security due to wireless broadcast characteristics. In this paper, we analyze the security vulnerabilities of DJI Aeroscope, a representative example of the R-ID-based UAV detection and identification system, and propose a replay-attack-based neutralization method using the analyzed vulnerabilities. To validate the proposed method, it is implemented as a software program, and verified against four types of attacks in real test environments. The results demonstrate that the proposed neutralization method is an effective neutralization method for R-ID-based UAV detection and identification systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.745-752
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• 2009

Management of social infrastructure has been advanced from facility management (FM) to asset management (AM), which adopts the aggressive and proactive methods in predicting the deterioration of infrastructure, prevents failures, and eventually saves maintenance cost. Infrastructure asset management is not a simple engineering technique, but it is a new paradigm evolved from facility management practices. To implement the infrastructure asset management successfully, organizational reform is very important. This paper suggests critical success factors and key performance indicators to implement the infrastructure asset management for facility managers of government owned social infrastructures such as roads and bridges. Reorganizing the facility management group requires new vision, objectives, strategies for the paradigm-changing asset management. This paper uses Balanced Score Card (BSC) which is a proven method in measuring and setting new objectives for an organization. Once the performance indicators are reviewed repeatedly by facility managers through experts workshops, developed BSC can be used in practice. This paper discusses the development of robust BSC scoring method through in depth literature reviews and investigation of asset management practices of domestic and international cases.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.30-39
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• 2023

Large dams, which are critical infrastructures for disaster prevention, are exposed to various risks such as aging, floods, and earthquakes. Better dam safety inspection and diagnosis using digital transformation technologies are needed. Traditional visual inspection methods by human inspectors have several limitations, including many inaccessible areas, danger of working at heights, and know-how based subjective inspections. In this study, drone photogrammetry was performed on two large dams to evaluate the applicability of digital data-based dam safety inspection and propose a data management methodology for continuous use. High-quality 3D digital models with GSD (ground sampling distance) within 2.5 cm/pixel were generated by flat double grid missions and manual photography methods, despite reservoir water surface and electromagnetic interferences, and severe altitude differences ranging from 42 m to 99.9 m of dam heights. Geometry profiles of the as-built conditions were easily extracted from the generated 3D mesh models, orthomosaic images, and digital surface models. The effectiveness of monitoring dam deformation by photogrammetry was confirmed. Cracks and deterioration of dam concrete structures, such as spillways and intake towers, were detected and visualized efficiently using the digital 3D models. This can be used for safe inspection of inaccessible areas and avoiding risky tasks at heights. Furthermore, a methodology for mapping the inspection result onto the 3D digital model and structuring a relational database for managing deterioration information history was proposed. As a result of measuring the labor and time required for safety inspection at the SYG Dam spillway, the drone photogrammetry method was found to have a 48% productivity improvement effect compared to the conventional manpower visual inspection method. The drone photogrammetry-based dam safety inspection is considered very effective in improving work productivity and data reliability.