• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.252-258
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• 2007

We have studied the feasibility of geostatistics approach to enhancing analysis of sparsely obtained seismic data by combining with satellite gravity data. The shallow depth and numerous fishing nets in The Yellow Sea, west of Korea, makes it difficult to do seismic surveys in this area. Therefore, we have attempted to use geostatistics to integrate the seismic data along with gravity data. To evaluate the feasibility of this approach, we have extracted only a few seismic profile data from previous surveys in the Yellow Sea and performed integrated analysis combining with the results from gravity data under the assumption that seismic velocity and density have a high physical correlation. First, we analyzed the correlation between extracted seismic profiles and depths obtained from gravity inversion. Next, we transferred the gravity depth to travel time using non-linear indicator transform and analyze residual values by kriging with varying local means. Finally, the reconstructed time structure map was compared with the original seismic section given in the previous study. Our geostatistical approach demonstrates relatively satisfactory results and especially, in the boundary area where seismic lines are sparse, gives us more in-depth information than previously available.

• Geophysics and Geophysical Exploration
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• v.15 no.1
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• pp.33-38
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• 2012

A resistivity method has been applied to wide range of engineering and environmental problems with the help of automatic and precise data acquisition. Thus, more accurate modeling and inversion of time-lapse monitoring data are required since resistivity monitoring has been introduced to quantitatively find out subsurface changes With respect to time. Here, we used the finite element method (FEM) for 3D resistivity modeling since the method is easy to realize complex topography and arbitrary shaped anomalous bodies. In the FEM, the linear elements, also referred to as first order elements, have certain advantages of simple formulation and narrow bandwidth of system equation. However, the linear elements show the poor accuracy and slow convergence of the solution with respect to the number of elements or nodes. To achieve the higher accuracy of finite element solution, high order elements are generally used. In this study, we developed a 3D resistivity modeling program using high order Serendipity elements. Comparing the Serendipity element solutions for a cube model with the linear element solutions, we assured that the Serendipity element solutions are more accurate than the linear element solutions in the 3D resistivity modeling.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.101-108
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• 1979

The viscosity of mucilage of Abelmoschus Manihot, Medic root decreased by the influence of various mechanical, physical and chemical conditions. It was experimented by viscosity decrease of mucilage connected with hydrogen ion concentration, bacterial multiplication, disinfection with 70% ethanol, some antibiotics, such as streptomycin, penicillin, ganamycin and chloramphenicol and mucilage derived from autoclaved Abelmoschus Manihot, Medic root. The results obtained were as follows: 1. It was clear that the viscosify of mucilage decreased notably under the influence of infected bacteria and bacterial multiplication. 2. By the inoculation of Bacillus subtilis ATCC 6633 and Escherichia coli ML 1410 to the mucilage the viscosify decrease fast but the viscosity of mucilage derived from autoclaved, Abelmoschus Manihot, Medic root. 3. The small quantity of reducing sugar in the mucilage was detected. 4. Hydrogan ion concentration in the mucilage remained $6.5{\sim}8.0$ in spite of the viscosity decrease.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.681-695
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• 2019

A Transient Storage Model (TSM) is one of the most widely used model accounting for complex solute transport in natural river to understanding natural river properties with four TSM key parameters. The TSM parameters are estimated via inverse modeling. Parameter estimation of the TSM is carried out by solving optimization problem about finding best fitted simulation curve with measured curve obtained from tracer test. Several studies have reported uncertainty in parameter estimation from non-convexity of the problem. In this study, we assessed best combination of optimization method and objective function for TSM parameter estimation using Cheong-mi Creek tracer test data. In order to find best optimization setting guaranteeing convergence and speed, Evolutionary Algorithm (EA) based global optimization methods, such as CCE of SCE-UA and MCCE of SP-UCI, and error based objective functions were compared, using Shuffled Complex-Self Adaptive Hybrid EvoLution (SC-SAHEL). Overall results showed that multi-EA SC-SAHEL with Percent Mean Squared Error (PMSE) objective function is the best optimization setting which is fastest and stable method in convergence.

• Geophysics and Geophysical Exploration
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• v.26 no.4
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• pp.229-237
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• 2023

The use of artificial sources such as explosives and mechanical vibrations for seismic exploration in urban areas poses challenges, as the vibrations and noise generated can lead to complaints. As an alternative to artificial sources, the surface waves generated by traffic noise can be used to investigate the subsurface properties of urban areas. However, traffic noise takes the form of plane waves moving continuously at a constant speed. To apply existing surface wave processing/inversion techniques to traffic noise, the recorded data need to be transformed into a virtual shot gather format using seismic interferometry. In this study, various seismic interferometry methods were applied to traffic noise data, and the optimal method was derived by comparing the results in the Radon and F-K domains. Additionally, the data acquired using various receiver arrays were processed using seismic interferometry, and the results were compared and analyzed to determine the most optimal receiver array direction for exploration.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.34-40
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• 2008

Underwater seismic refraction with advanced interpretation approaches makes important contributions to shallow marine exploration and geotechnical investigations in Australia's coastal areas. A series of case studies are presented to demonstrate the recent applications of continuous and static USR methods to river crossing and port infrastructure projects at various sites around Australia. In Sydney, static underwater seismic refraction (USR) with bottom-placed receivers and borehole seismic imaging assisted the development of improved geotechnical models that reduced construction risk for a tunnel crossing of the Lane Cove River. In Melbourne, combining conventional boomer reflection and continuous USR with near-bottom sources and receivers improved the definition of a buried, variably weathered basalt flow and assisted dredging assessment for navigation channel upgrades at Geelong Ports. Sand quality assessment with continuous USR and widely spaced borehole information assisted commercial decisions on available sand resources for the reclamation phase of development at the Port of Brisbane. Buried reefs and indurated layers occur in Australian coastal sediments with the characteristics of laterally limited, high velocity, cap layers within lower velocity materials. If these features are not recognised then significant error in depth determination to deeper refractors can occur. Application of advanced refraction inversion using wavefront eikonal tomography to continuous USR data obtained along the route of a proposed offshore pipeline near Fremantle allowed these layers and the underlying bedrock refractor to be accurately imaged. Static USR and the same interpretation approach was used to image the drowned granitic regolith beneath sediments and indurated layers in the northern area of Western Australia at a proposed new berthing site where deep piling was required. This allowed preferred piling sites to be identified, reducing overall pile lengths. USR can be expected to find increased application to shallow marine exploration and geotechnical investigations in Australia's coastal areas as economic growth continues and improved interpretation methods are developed.

• Archives of design research
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• v.20 no.3 s.71
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• pp.279-288
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• 2007

Today, design is not free from fashion, which emerges and vanishes temporarily, and aims at equalization. As a result, products quickly become obsolete because of fashion. This means that the span of products is determined by a social concept, which is not clarified, regardless of their functions. Usable products will gradually disappear from us and it will cause serious environmental problems, unless we can find out measures against fashion. As such, it is important to study the characteristics of the shaker's design in this circumstance. The Shaker's community has a distinguishable difference from other general societies. Temporary fashion and misled information cannot interfere with their consciousness. Religion, the life and the principle of design have developed on the same level in their community. Especially, any decoration or the difference of materials is not allowed in shaker's design. It reflects their thinking that all people are equal in the sight of God. Therefore, any decoration for social and economical superiority can not be used. Through this consciousness, they can be free from fashion or decoration. They, also, believe that they can reach perfection through practicality and simplicity. The reason why shaker's design is not disturbed by fashion is that their belief is involved in their design. Consequently, if religious or conscious contents are primarily set up, design can be free from fashion and products can be used for a long time.

• Archives of design research
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• v.20 no.3 s.71
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• pp.299-314
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• 2007

For the past 20 years, the growth and development of university-design-educational institutes contributed to the industrial development of our country. Due to the technological fluctuation and changes in the industrial structure in the latter half of the 20th century, the enterprise is demanding professionally-oriented design manpower. The principle which appears from instances of the advanced nations is to accommodate the demands in social changes and apply them to educational design programs. In order to respond promptly to the industrial demand especially, the advanced nations adopted "multidisciplinary design education programs" to lead innovation in the area of design globally. The objective of the research consequently is to suggest an educational system and a program through which the designer can be educated to obtain complex knowledge and the technique demanded by the industry and enterprise. Nowadays in order to adapt to a new business environment, designers specially should have both the knowledge and techniques in engineering and business administration. We suggest that the IPDI, a multidisciplinary design educational system and program is made up of the coordinated operation of major classes, on-the-job training connection, educational system for research base creation, renovation design development program for the application and the synthesis of alternative proposals about the training facility joint ownership by connecting with the education of design, business administration and engineering.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.1-14
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• 2008

We present a method for interpreting seismic records with arrivals and waveforms having characteristics which could be generated by extremely inhomogeneous velocity structures, such as non-typical oceanic crust, decollement at subduction zones, and seamounts in oceanic regions, by comparing them with synthetic waveforms. Recent extensive refraction and wide-angle reflection surveys in oceanic regions have provided us with a huge number of high-resolution and high-quality seismic records containing characteristic arrivals and waveforms, besides first arrivals and major reflected phases such as PmP. Some characteristic waveforms, with significant later reflected phases or anomalous amplitude decay with offset distance, are difficult to interpret using only a conventional interpretation method such as the traveltime tomographic inversion method. We find the best process for investigating such characteristic phases is to use an interactive interpretation method to compare observed data with synthetic waveforms, and calculate raypaths and traveltimes. This approach enables us to construct a reasonable structural model that includes all of the major characteristics of the observed waveforms. We present results here with some actual observed examples that might be of great help in the interpretation of such problematic phases. Our approach to the analysis of waveform characteristics is endorsed as an innovative method for constructing high-resolution and high-quality crustal structure models, not only in oceanic regions, but also in the continental regions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.666-672
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• 1997

Twenty years' daily mean air temperature data was used to calculate the critical early seeding date(CESD), the optimum heading date(OHD), the critical late heading date for stable ripening(CHDR) and the critical late ripening date(CLRD) for rice seeded on dry paddy in different agroclimatic zones in Korea. The CESD was defined as the first day with mean air temperature of 13$^{\circ}C$, and the OHD as the first day of the 40 consecutive days with mean air temperature of 22$^{\circ}C$ or above after heading. The CHDR was defined as the date after which the cumulative daily mean air temperature would be at least 76$0^{\circ}C$. Lastly, the CLRD was defined as the last day when daily mean air temperature remains above 15$^{\circ}C$. This information was used for the estimation of periods from the earliest date of seeding to optimum heading date, the latest possible date of heading and the latest possible date of ripening in respective regions. For instance, in Suwon, those respective periods mentioned were found to be 104days, 124days, and 165days.