• Structural Engineering and Mechanics
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• v.58 no.6
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• pp.949-966
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• 2016

The second order analysis taking place due to non-linear behavior of the structures under the mechanical and geometric factors through implementing exact and approximate methods is an indispensible issue in the analysis of such structures. Among the exact methods is the slope-deflection method that due to its simplicity and efficiency of its relationships has always been in consideration. By solving the differential equations of the modified slope-deflection method in which the effect of axial compressive force is considered, the stiffness matrix including trigonometric entries would be obtained. The complexity of computations with trigonometric functions causes replacement with their Maclaurin expansion. In most cases only the first two terms of this expansion are used but to obtain more accurate results, more elements are needed. In this paper, the effect of utilizing higher order terms of Maclaurin expansion on reducing the number of required elements and attaining more rapid convergence with less error is investigated for the Bernoulli beam with various boundary conditions. The results indicate that when using only one element along the beam length, utilizing higher order terms in Maclaurin expansion would reduce the relative error in determining the critical buckling load and kinematic parameters in the second order analysis.

• Steel and Composite Structures
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• v.20 no.5
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• pp.999-1022
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• 2016

The use of Carbon Fiber Reinforced Polymer (CFRP) to strengthen steel structures has attracted the attention of researchers greatly. Previous studies demonstrated bonding of CFRP plates to the steel sections has been a successful method to increase the mechanical properties. However, the main limitation to popular use of steel/CFRP strengthening system is the concern on durability of bonding between steel and CFRP in various environmental conditions. The paper evaluates the performance of I-section steel beams strengthened with pultruded CFRP plate on the bottom flange after exposure to diverse conditions including natural tropical climate, wet/dry cycles, plain water, salt water and acidic solution. Four-point bending tests were performed at specific intervals and the mechanical properties were compared to the control beam. Besides, the ductility of the strengthened beams and distribution of shear stress in adhesive layer were investigated thoroughly. The study found the adhesive layer was the critical part and the performance of the system related directly to its behavior. The highest strength degradation was observed for the beams immersed in salt water around 18% after 8 months exposure. Besides, the ductility of all strengthened beams increased after exposure. A theoretical procedure was employed to model the degradation of epoxy adhesive.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.31-39
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• 2017

The paper presents the Philippine maritime condition, safety systems and navigational aids. It aims to uplift the maritime safety systems and infrastructures by studying the different strata of the industry, thereby emphasizing on the structures, weaknesses and opportunities. It presents the different maritime agencies involved and each responsibilities. Data from PPA demonstrate the statistics of increase in the cargo throughput, passenger, shipcalls and cargo-container handled in the year 2014. It also highlights the insufficiency of different navigational aids, VTMS, MBS and TSS placed in the whole archipelago. It gathers data of maritime accidents in 10-year period, 2006-2015, showing the most occurred accidents, casualties and areas these accidents happened. It includes the weather phenomena which contribute to the maritime movements and accidents incidence. The results show that systems and infrastructures that focus on the lack of improvement in technology and over-lapping functions of different agencies of government require development and upgrading.

• Advances in Computational Design
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• v.2 no.3
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• pp.211-223
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• 2017

This research presented a numerical and experimental study on the seismic performance of first-generation base-isolated and fixed-base nuclear power plants (NPP). Three types of the base isolation system were applied to rehabilitate the first-generation nuclear power plants: frictional pendulum (FP), high-damping rubber (HDR) and lead-rubber (LR) base isolation. Also, an Excel program was proposed for the design of the abovementioned base isolators in accordance with UBC 97 and the Japan Society of Base Isolation Regulation. The seismic assessment was performed using the pushover and nonlinear time history analysis methods in accordance with the FEMA 356 regulation. To validate the adequacy of the proposed design procedure, two small-scale NPPs were constructed at Universiti Teknologi Malaysia's structural laboratory and subjected to a pushover test for two different base conditions, fixed and HDR-isolated base. The results showed that base-isolated structures achieved adequate seismic performance compared with the fixed-base one, and all three isolators led to a significant reduction in the containment's tension, overturning moment and base shear.

• International Commerce and Information Review
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• v.10 no.1
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• pp.3-31
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• 2008

Northeast Asia is expected to be on economic bloc which is competed with other economic blocs such as EU, NAFTA. E-Commerce based on IT and networking results in paradigm shift in Northeast Asian Nations, that is, Korea, China, Japan, Taiwan etc. There are the similarities and differences in e-Commerce situations in these nations. The differences are the gaps in e-Commerce infrastructures such as Internet, e-Commerce solution, e-payment system and e-logistics system etc. A number of interorganizational, intraorganizational and usage level factors influences the performances of all firms using e-Commerce tools. As result of this empirical study, China records low level of e-Commerce in terms of environmental aspects, usage and performance while Korea and Japan record relatively high levels. It is also found that non-economic performance is higher than economic performance in Northeast Asian firms. The purpose of this paper contributes to resolve the digital divide in Northeast Asia and to improve e-Commerce infrastructures in Northeast Asia by estimating current e-Commerce levels of Northeast Asian countries and suggesting future development strategies of those countries through e-Commerce cooperation.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.40-46
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• 2006

This paper presents a novel fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy cabling, and low cost. In this paper, a prototype of the fiber optic accelerometer system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. A unique algorithm has also been developed to derive the sensor's acceleration from the raw signals of the light control unit; it is implemented via a separate signal processing unit. Finally, the shaking table tests successfully demonstrate the performance and the potential of the moire fringe fiber optic sensor system to monitor the health of civil infrastructures.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.305-317
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• 2015

The function failure of present major facilities is likely to lead to failure of related systems and/or whole facilities, increasing the necessity for protection of infrastructures, main structures, and major industrial facilities. In addition, safe and efficient management for urban infrastructure (waterworks and sewerage facilities, electricity, telecommunications, roads, etc) installed in the basement or on large cities grounds at various public areas is required. Recently in response to this demand, efforts for vitalizing asset management are being made such as enacting related laws and developing asset management system in the U.S., Australia, Europe and other advanced countries with the concept for a new maintenance. In our county, identifying maintenance system problems such as aging and rapid increasing of existing infrastructures and decision-making about updating maintenance is required for systematic and organizational maintenance. In this study, by comparing and observing the LOS(Level of Service) of each countries' waterworks and risk-based LOS, we suggest the direction of future urban water infrastructure management systems for more effective management.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.3-13
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• 2016

The development impact fee (DIF) zoning is used to adequately provide the pre-planned urban infrastructures in those urban and regional sectors where significant urban sprawl has already taken place followed by the rapid population growth. The infrastructure installation fees are levied to those landowners whose properties belong to the DIF zone in which they enjoy the direct benefits that accrue from the installed infrastructures. While the law is deemed to be equitable in that the actual beneficiaries pay for their benefits, it is required to designate the zone boundaries accurately and consistently since they are the very dividers that differentiate the legitimate fee-payers and the free-riders. This study, especially, tries to test a seemingly advanced alternative, so-called the cost-weighted distance measure, as a potential candidate to replace the current air-distance measures to designate the zone boundaries. The statistics indicate that the coefficient of variation for major indices spread from 11.75 to 35.6 in the case of the latter method, it only ranges from 0.21 to 0.76 in the case of the former. The zonal outcomes also show much higher consistency in their shapes. It is hoped, in this context, that the study findings could possibly be adopted in the future research efforts expected soon to amend and improve the current DIF zoning law.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.549-555
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• 2003

The objective of かis study is to investigate the feasibility of piezoelectric transducers as a damage detection system for civil infrastructures. There have been considerable amount of efforts by the modal analysis community to localize damage and evaluate its severity without looking at a reliable way to excite the structure. The detection of damages by modal analysis and similar vibration techniques depends upon the knowledge and estimation of various modal parameters. In addition to the associated difficulties, such low-frequency dynamic response based techniques fail to detect incipient damages. Smart piezoelectric ceramic (PZT) transducers which act as both actuators and sensors in a self-analyzing manner are emerging to be effective in non-parametric health monitoring of structural systems. In this paper, we present the results of an experimental study for the detection of damages using smart PZT transducers on the steel plate. The method of extracting the impedance characteristics of the PZT transducer, which is electro-mechanically coupled to the host structure, is adopted for damage detection. Two damages are simulated and assessed by the bonded PZT transducers for characterization. The experimental results verified the efficacy of the proposed approach and provided a demonstration of good robustness at the realistic steel structures, emphasizing the great potential for developing an automated in situ structural health monitoring system for application to large civil infrastructures without the need to blow the modal parameters.

• Journal of the Korean association of regional geographers
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• v.15 no.1
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• pp.161-178
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• 2009

The introduction of a world geodetic system for cadastral survey will be started the enactment of the law on survey, hydro-graphical examination and cadastre. However, the cadastral control points are not homogeneous and correspond with national control points because of various reasons. To cope with this problem, the 1,600 high accurate control points, which can be interlocked with national GPS control points, has selected from existing 20,000 cadastral control points. These selected control points were calculated as an accurate world geodetic system and it makes a homogeneous cadastral survey network. Through these measures, for the future carrying out national project, this study will be effectively contributed to establish the cadastral infrastructures for the Korea cadastral reform project.