• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.343-354
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• 2021

The frequencies formulas of the bridge are of great importance in the design process since these formulas provide insight dynamic characteristics of the structure, which guides the designers to parametric analyses and the layout of the bridge in conceptual or preliminary design. Continuous rigid frame bridge is popular in the mountainous area. Mostly, this type of bridge was simplified either as a girder or cantilever when calculating the frequency, however, studies showed that the different configuration of the bridge made the problem more complex, and there is no unified fundamental calculation pattern for this kind of bridge. In this study, an empirical frequency equation is proposed as a function of pier's height, stiffness of pier and the weight of the structure. A unified fundamental frequency formula is presented based on the energy principle, then the typical continuous rigid frame bridge is investigated by finite element method (FEM) to study the dynamic characteristics of the structure, and then several key parameters are investigated on the effect of structural frequency. These parameters include the number, position and stiffness of the tie beam. Nonlinear regression analyses are conducted with a comprehensive statistical study from plenty of engineering structures. Finally, the proposed frequency equation is validated by field test results. The results show that the fundamental frequency of the continuous rigid frame bridge increases more than 15% when the tie beams are set, and it increases with the stiffness ratio of tie beam to pier. The results also show that the presented unified fundamental frequency has an error of 4.6% compared with the measured results. The investigation can predicate the approximate longitudinal fundamental frequency of continuous ridged frame bridge, which can provide reference for the seismic response and dynamic impact factor design of the pier.

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.315-318
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• 2004

• Journal of Wetlands Research
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• v.15 no.4
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• pp.519-527
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• 2013

The Ministry of Environment of the Republic of Korea set up 'the $2^{nd}$ Fundamental Plan for Wetlands Conservation' to facilitate systematic surveys and management of various national wetlands and to promote sustainable conservation and use of those wetlands. The mid-term fundamental plan was established in accordance with the Article 5 of the Wetland Conservation Act, which spans 5 years from 2013 to 2017 and covers national wetlands including inland wetlands and coastal wetlands stated in the Act. The fundamental plan aims to promote the wise use of wetlands through establishing policies for sustainable conservation based on the assessment of implementation of the $1^{st}$ Fundamental Plan, setting up a scientific framework for establishment and implementation of national wetland policies by improving wetland survey systems and enhancing basis wetland data, improving the ecological health of wetlands and securing biodiversity conservation of wetlands by strengthening conservation and management system of national wetlands, and through raising public awareness and diversify education and promotion tools. The main objectives of the $2^{nd}$ Fundamental Plan is to revise the entire Wetland Conservation Act, to create a new monitoring system of national inland wetlands, to upgrade the national wetlands inventory, to reflect the 'Ecological Map' for promoting precautionary management of wetlands, to improve the 'Wetland Restoration and Management' system to build wetlands resilience, and to systematize the wise use of wetlands that benefits local people. As the Ministry of Environment plans to establish its other master plan for wetland conservation based on the $2^{nd}$ Fundamental Plan, this document introduces the $2^{nd}$ Fundamental Plan to stakeholder and wetland professions.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.19
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• pp.67-93
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• 2003

The CISG approach was intended to make the remedial system clear, but produced ambiguity, and complexity. The CISG does not differentiate between main, auxiliary and participatory obligations. There is no distinction between breaches of main or breaches of auxiliary obligations, rather, a distinction is made between fundamental and other breaches of contract. Articles 25 gives the definition of fundamental breach of contract. This concept is the essential of avoidance and remedial system in the CISG. This concept, however, is ambiguous. The fact that the fundamentality of a breach of contract in many cases is the condition for an avoidance of contract, is expression of the trend of the CISG to preserve contracts, which I consider as essential in international trade. The elements which define a substantial detriment are extremely complex. It will become obvious that the relevant detriment is not a static element, but in many instances occurs only when the breach of contract continues. It should be added that it is the circumstances of each individual case which are relevant. It is to be stressed that a fundamental breach of contract must constitute also a non-fulfillment of a contractual obligation.

• Earthquakes and Structures
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• v.19 no.2
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• pp.119-128
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• 2020

In seismic design of a pylon supporting transmission lines in an overhead electricity transmission system, an estimation of the fundamental periods of the pylon in two orthogonal vertical planes is necessary to compute the seismic forces required for sizing pylon members and checking pylon deflections. In current practice, the fundamental periods of a pylon in two orthogonal vertical planes are typically obtained from eigenvalue analyses of a model consisting of the pylon of interest as well as some adjacent pylons and the transmission lines supported by these pylons. Such an approach is onerous and numerically inconvenient. This research focused on development of a simplified method to determine the fundamental periods of pylons. The simplified method is rooted in Rayleigh's quotient and is based on a single-pylon model. The force vectors that can be used to generate the shape vectors required in Rayleigh's quotient are presented in detail. Taking three pylons selected from representative overhead electricity transmission systems having different design parameters as examples, the fundamental periods of the chosen pylons predicted from the simplified method were compared with those from the rigorous eigenvalue analyses. Result comparisons show that the simplified method provides reasonable predictions and it can be used as a convenient surrogate for the tedious approach currently adopted.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1438-1445
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• 2008

The purpose of this study is to evaluate the fundamental frequency of the dam by the various methods using real microearthquake records which were measured on 'H' dam site and to compare each results. In this study, the fundamental frequency was evaluated by the frequency analysis of the microearthquake records which were measured on the dam crest, by the evaluation of acceleration amplification ratio between the foundation and the crest of dam, and by the evaluation of acceleration response spectrum ratio between the foundation and the crest of dam, respectively. Among these methods, it was found that the method by the evaluation of acceleration response spectrum ratio between the foundation and the crest of dam was the most effective method. But, if the simple engineering judgement can be considered, it was thought that the all three methods could reasonably evaluate the fundamental frequency of the dam.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.15-20
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• 2019

Fundamental processes in digital forensic investigation - such as disk imaging - were developed when digital investigation was relatively young. As digital forensic processes and procedures matured, these fundamental tools, that are the pillars of the reset of the data processing and analysis phases of an investigation, largely stayed the same. This work is a study of modern digital forensic imaging software tools. Specifically, we will examine the feature sets of modern digital forensic imaging tools, as well as their development and release cycles to understand patterns of fundamental tool development. Based on this survey, we show the weakness in current digital investigation fundamental software development and maintenance over time. We also provide recommendations on how to improve fundamental tools.

• Spatial Information Research
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• v.20 no.1
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• pp.39-45
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• 2012

Response of buildings under seismic load is different according to fundamental period. It is provided in Korean Building Code(KBC2009) seismic response coefficient by fundamental period for seismic design of buildings. Recently, many researchers have studied on fundamental period and seismic response coefficient. However, studies on seismic design using Geographic Information System(GIS) are not sufficient. Therefore, this paper has analyzed on seismic response coefficient of buildings using ArcGIS. This paper can be evaluated efficiently for seismic analysis of structures. And this study will be used as basics of a reasonable seismic design using Geographic Information Systems(GIS).

• Nuclear Engineering and Technology
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• v.47 no.2
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• pp.219-225
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• 2015

In this paper, a three-dimensional model for the dynamic analysis of a flywheel based on the finite element method is presented. The static structure analysis for the model provides stress and strain distribution cloud charts. The modal analysis provides the basis of dynamic analysis due to its ability to obtain the natural frequencies and the vibration-made vectors of the first 10 orders. The results show the main faults are attrition and cracks, while also indicating the locations and patterns of faults. The harmonic response simulation was performed to gain the vibration response of the flywheel under operation. In this paper, we present a Hilbert-Huang transform (HHT) algorithm for flywheel vibration analysis. The simulation indicated that the proposed flywheel vibration signal analysis method performs well, which means that the method can lay the foundation for the detection and diagnosis in a reactor main coolant pump.

• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.77-89
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• 2017

This study investigates the phonetic meaning of clarity and turbidity(淸濁) that has been used in psychoacoustics, musicology, and linguistics in both the East and the West. With a view to clarifying the phonetic meaning of clarity and turbidity, this study conducts three perception tests. First, 34 subjects were asked to take one of Clear and Turbid by forced choice for 5 pure and complex tones, respectively, ranging from A2 to A6 differing by octave. Second, they were asked to select between the two choices for 25 pure and complex tones, respectively, ranging from A2 to A4 differing by semitone. Third, they were asked to opt for one of the two choices for 8 different vowels of different formant and fundamental frequencies. Results showed that there is a certain range of tone which is perceived as clear, that clarity level increases as fundamental frequency increases, and that pure tones have a higher level of clarity than complex ones, fundamental frequency being equal. Results also showed that vocal tract resonance enhances clarity level on the whole, and that lower vowels have a higher level of clarity than higher ones. This study is significant in that it demonstrates that clarity level is proportional to fundamental frequency and the first formant frequency, all else being equal.