• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1C
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• pp.21-31
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• 2009

Based on the proven feasibility of bottom ash and tire shred-soil mixtures as lightweight fill materials, tire shred-bottom ash mixtures were suggested as a new lightweight fill material to replace the conventional construction material (soil) with bottom ash. Therefore, we carried out the field compaction test and performance test of large scale embankment in order to evaluate their suitability for the use of lightweight fill materials. In these tests, we could assess the settlement, earth pressure, stress-strain relation, vibration of large scale embankment which were made with tire shred-bottom ash mixture and the conventional fill material(weathered soil) respectively. The earthpressure and vibration transmission was decreased and the settlement behaviour of the 2 materials (tire shred mixture and weathered soil) was measured similarly under static/cyclic loading condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.699-707
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• 2008

For most structural evaluation of bridge integrity, it is very important to measure the geometric profile, which is a major factor representing the global behavior of civil structures, especially bridges. In the past, because of the lack of appropriate methods to measure the deflection profile of bridges on site, the measurement of deflection has been restricted to just a few discrete points along the bridge, and the measuring points have been limited to the locations installed with displacement transducers. Thus, some methods for predicting the static deflection by using fiber optic strain sensors has been applied to simply supported bridges. In this study, a method of estimating the static deflection profile by using strains measured from suspension bridges was proposed. Based on the classical deflection theory of suspension bridges, an equation of deflection profile was derived and applied to obtain the actual deflection profile on Namhae suspension bridge. Field load tests were carried out to measure strains from FBG strain sensors attached inside the stiffening girder of the bridge. The predicted deflection profiles were compared with both precise surveying data and numerical analysis results. Thus, it is found that the equation of predicting the deflection profiles proposed in this study could be applicable to suspension bridges and the FBG strain sensors could be reliable on acquiring the strain data from bridges on site.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.156-167
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• 2009

This study investigated the effects of dynamic visual on students' field independence-dependence on connecting errors and conceptual understanding in learning chemistry concepts with multiple representations. Seventh graders (N=123) at a co-ed middle school were assigned to a static visual (SV) group learning with text and static visual, and a dynamic visual (DV) group learning with text and dynamic visual. The students then learned 'Boyle's Law' and 'Charles's Law' for two class periods. Results revealed that the percentages of the DV group were lower than those of the SV group on connecting errors. However, the percentages of the students' connecting errors were still high regardless of their field independence-dependence. There was a little different tendency in the percentages of connecting errors between the two groups by students' field independence-dependence according to the types of connecting errors. The scores of the DV group were significantly higher than those of the SV group in a test on conceptual understanding. However, there was no significant interaction between the instruction and the students' field independence-dependence. Educational implications of these findings are discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11C
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• pp.1102-1110
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• 2007

In this paper, we design the FPGA (Field-Programmable Gate Array) of the CAMB (Constant-Amplitude Multi-code Biorthogonal) modulation, and implement the SoC (System on Chip). The ASIC (Application Specific Integrated Circuit) chip is be implemented through targeting and board test. This 12Mbps modem SoC includes the ARM (Advanced RISC Machine)7TDMI, 64Kbyte SRAM(Static Random Access Memory) and ADC (Analog to Digital Converter)/DAC (Digital to Analog Converter) for flexible applications. Additionally, the modem SoC can support the variable communication interfaces such as the 16-bits PCMCIA (Personal Computer Memory Card International Association), USB (Universal Serial Bus) 1.1, and 16C550 Compatible UART (Universal Asynchronous Receiver/Transmitter).

• Journal of the Korean GEO-environmental Society
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• v.24 no.2
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• pp.13-24
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• 2023

Tunnels may undergo a larger or a smaller response compared with the free-field soil. In the pseudo-static procedure, the response of the tunnel is most often characterized by a curve that relates the racking ratio (R) with the flexibility ratio (F), where R represents the ratio of the tunnel response with respect to the free-field vibration and F is the relative stiffness of the tunnel and the surrounding soil. A set of analytical and empirical curves that do not account for the depth and the aspect ratio of the tunnel are typically used in practice. In this study, a series of dynamic analyses are conducted to develop a set of F-R_m relations for use in a frame analysis method. R_m is defined as an adjusted R where the rocking mode of deformation is removed and only the racking deformation is extracted. The numerical model is validated against centrifuge test recordings. The influence of aspect ratio, buried depth of tunnel on results is investigated. The results show that R_m increases with the increase of the buried depth and the aspect ratio. The widely used F-R relations are highlighted to be different compared with the obtained results in this study. Therefore, the updated F-R_m relations with proposed equations are recommended to be used in practice design. The rocking response decreases with either the decrease of the difference of stiffness between surrounding soil and tunnel or the larger aspect ratio of the tunnel section.

• Journal of Biosystems Engineering
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• v.39 no.3
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• pp.158-165
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• 2014

Purpose: The objective of this paper was to compare test standards regarding the performance and safety of agricultural tractors to identify the differences in test conditions, measurement tolerances, and test procedures. Based on the comparison, some recommendations were proposed for possible revisions or improvements to current tractor test standards. Methods: The test standards and codes of major standards development organizations (SDOs), such as the Organization for Economic Cooperation and Development (OECD), the International Organization for Standardization (ISO), the American Society of Agricultural and Biological Engineers (ASABE), EC type approval, and the board of actions of the Nebraska Tractor Test Laboratories (NTTL), were selected and analyzed. Comparison of the test standards: The ISO provides references for fuel and lubricants for tractor tests, and the OECD provides additional measurements for calculating fuel consumption characteristics during the power take-off (PTO) tests. The ISO, EC type approval, and the ASABE provide PTO protective device and the safety requirements. During drawbar power tests, seven transmission ratios are selected for fully automatic transmissions, according to the OECD. In case of hydraulic lift tests, ISO 789-2 and OECD Code 2 advise the use of a static lift force, while SAE J283 advises the use of additional dynamic lift capacity tests for a better representation of in-field operations. The OECD, the ISO, and EC type approval determine the seat index point (SIP), whereas the ASABE determines the seat reference point (SRP) for roll-over protective structure (ROPS) tests. Diversified measurement tolerances were among the braking performance test standards. The European Union (EU) has developed daily limits for vibration exposures with adaptations from ISO 2631-1. Electromagnetic compatibility evaluations are emerging of high-efficiency tractors due to the long-term conformance to electromagnetic emissions and interferences. Comparisons of tractor test standards discussed in this paper are expected to provide useful information for tractor manufacturers and standards development personnel to improve the performance and safety test standards of tractors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.361-364
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• 2005

Some bogie frames manufactured in 1999, 2000 year have the fatal problem. Three or four years later, the cracked end beam among them have discovered in 2002, 2003 year. The crack situation of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment. To improve the end beam, a research of covering the whole field of welded type bogie frame was started. Main line real tests were performed at Young-Dong line. The stress of main positions for bogie frame was measured. Also up-down direction and left-right direction vibration acceleration of the bogie frame were measured. At this time the tests were performed for the three types bogie. The test result concludes that the crack cause of the end beam is not brake load but vibration at running mainly. It is estimated that the life of the improved car which end beam reinforced is safe within the car permitted life(25 years). The improvement methods of the end beam are presented by construction modification, parts modification. The integrity evaluation is inspected by analysis the real line test results, the improvement methods of the end beam.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.1-11
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• 2023

A growing trend of utilizing helical piles for soft soil strata to support infrastructure projects is currently observed in Saemangeum, South Korea. Recognized mainly due to its ease of installation and reusability proves to be far more superior compared to other foundation types in terms of sustainability. This study applies modified p-y springs to characterize the behavior of a laterally loaded helical pile with a shaft diameter of 89.1 mm affixed with 3 helices evenly spaced along its embedded length of 2.5 m. Geotechnical soil properties are correlated from CPT data near the test bed vicinity and strain gauges mounted on the shaft surface. A modification factor is applied on the p-y springs to adjust the simulated data and match it to the bending moment, soil resistance and deflection values from the strain gauge measurements. The predicted lateral behavior of the helical pile through the numerical analysis method shows fairly good agreement to the recorded field test results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.53-60
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• 2020

In this study, smart precast-in-place concrete, such as continuity with Precast any technology that can be the Application of Building Structures and railway stations, civil structures. After the same way in the field installation design based on the criteria railways and derived the right section, through the Static and Dynamic Response Analysis. Dynamic sensor and the triaxial acceleration measured by attaching the sensor acceleration response according to the extent of the damage of Precast Panel Structures and mode of Precast Structures, by comparing the data. Data for the stability and improvement of the uncertainty in along a railroad and Future of Precast Panel Structures of time to replace. This is to use this data as basic data on damage prediction.

• Journal of the Korean GEO-environmental Society
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• v.9 no.1
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• pp.41-46
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• 2008

In this study, the analysis of load transition of PHC pile was performed with the static load test, which was driven in deep soft clay layer of MyungJi site in the western area of Pusan. The results of test showed that the range of unit side resistance of pile in sand layer were $7.4t/m^2$ to $23.3t/m^2$ and $6.4t/m^2$ in the soft clay layer, while the unit base resistance was $955t/m^2$ in dense silty sand layer. To select the most reasonable static bearing capacity formular, the field measured values are compared with the calculated ones from the suggested various formular. In the case of side resistance in sand layer, the suggest formular in the Structural Foundation Design Manual by KGS was most reasonable, while in clay layer Railroad Design Manual.