• Geophysics and Geophysical Exploration
• /
• v.5 no.2
• /
• pp.108-117
• /
• 2002

We have introduced a new approach to obtain the conductivity information of subsurface using Cagniard impedance over two-dimensional (2-D) model in the presence of horizontal magnetic dipole source with the frequency range of $1\;kHz\~1\;MHz$. Firstly, we designed the method to calculate the apparent resistivity from the ratio between horizontal electric and magnetic fields, Cagniard impedance, considering the source effects when the plane wave assumption is failed in finite source EM problem, and applied it to several numerical models such as homogeneous half-space or layered-earth model. It successfully provided subsurface information even though it is still rough, while the one with plane wave assumption is hard to give useful information. Next, through analyzing Cagniard impedance and apparent resistivity considering source effect over 2-D models containing conductive- or resistive-block, we showed that the possibility of obtaining conductivities of background media and anomaly using this approach. In addition, the apparent resistivity considering source effect and phase pseudosections constructed from Cagniard impedance over the isolated conductive- and resistive block model well demonstrated outlines of anomalies and conductivity distribution even though there were some distortions came from sidelobes caused by 2-D body.

• Journal of the Korea Society for Simulation
• /
• v.15 no.2
• /
• pp.59-69
• /
• 2006

Component-based software development is introduced as a new development paradigm in software development method. This approach is different from existing software development approach because it is based on reusable and autonomous unit, component. Therefore, component-based development(CBD)is divided into two stages; component development process and component assembly process; application development process. Component development process is the core of CBD because component has a key for good software. Currently many methodologies or tools have been introduced by various academies or industries. However, those don't suggest systematic and flexible modeling techniques adaptable easily into component development project. Existing approaches have a unique orarbitrary modeling technique or provide heuristic guidelines for component modeling. As a result, many component developers are faced with a difficult problems; how to developcomponent models, when develop which diagrams, and so on. In order to address this problem, we suggest a meta-model driven approach for component development in this paper. We provide meta-models according to both layer and development phase. We expect that suggested meta-models allow component developers to develop appropriate models of the time.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.2
• /
• pp.15-21
• /
• 2013

The analysis of long-term performance of pavement sections under wheel loads is normally conducted in two separated steps. First the resilient behavior of the pavement is calculated assuming the pavement is a layered or discrete elastic medium, and then the permanent deformation is evaluated based on empirical permanent displacement equations. Material properties required in both steps can be obtained from cyclic triaxial tests, in other words, resilient and permanent deformation tests. While this analytical approach is simple and convenient, it does not consider the modulus degradation caused by cyclic loads, and some types of reinforcements such as geosynthetic cannot be modeled in this type of analysis. A model for degraded secant modulus is proposed and suggested to be used for the analysis of permanent behavior of unpaved roadway sections. The parameter for suggested model can be obtained from cyclic triaxial tests, regular practice in pavement engineering. Examples to estimate the model parameters are presented based on both laboratory permanent deformation test and large-scale plate load test.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.25 no.2
• /
• pp.23-38
• /
• 2022

This study investigates the characteristics and physical habitat requirements for each Bufo gargarizans life history through a literature survey. After deriving variables for each component of Bufo gargarizans, in order to reduce regional deviations from eight previously studied literature research areas for deriving the criteria for variables, a total of 12 natural habitats of Bufo gargarizanss are selected as spatial ranges by selecting four additional sites such as Umyeonsan Ecological Park in Seoul, Wonheungibangjuk in Cheongju in the central region, Changnyeong Isan Reservoir in the southern region, and Mangwonji in Daegu. This study presents Bufo gargarizans SI, a species endemic to Korea, whose population is rapidly declining due to large-scale housing site development and road development, and develops a Bufo gargarizans HSI model accordingly to improve the function of the damaged Bufo gargarizans habitat and to present an objective basis for site selection of alternative habitat. At the same time, it provides basic data for adaptive management and follow-up monitoring. The three basic habitat requirements of amphibians, the physical habitat requirements of Bufo gargarizans, synthesized with shelter, food, and water, and the characteristics of each life history, are classified into five components by adding space and threats through literature research and expert advice. Variables are proposed by synthesizing and comparing the general characteristics of amphibians, among the previously studied single species of amphibians, the components of HSI of goldfrogs and Bufo gargarizans, and the ecological and physical environmental characteristics of Bufo gargarizans. Afterwards, through consultation with an amphibian expert, a total of 10 variables are finally presented by adjacent forest area(ha), the distance between spawning area and the nearest forest land(m), the soil, the distance from the wetland(m), the forest layered structure, the low grassland space, the permanent wetland area(ha), shoreline slope(%), PH, presence of predators, distance from road(m), presence or absence of obstacles. n order to derive the final criteria for each of the 10 variables, the criteria(alternative) for each variable are presented through geographic information analysis of the site survey area and field surveys of the previously studied literature research area. After a focus group interview(FGI) of 30 people related to the Bufo gargarizans colony in Cheongju, a questionnaire and in-depth interviews with three amphibians experts are conducted to verify and supplement the criteria for each final variable. Based on the finally developed Bufo gargarizans HSI, the Bufo gargarizans habitat model is presented through the SI graph model and the drawing centering on the Bufo gargarizans spawning area

• The Journal of the Korea Contents Association
• /
• v.12 no.8
• /
• pp.1-12
• /
• 2012

We develop the Spatio-Temporal Graph to imbue the historical context to the situations in a virtual world, and an ontology to enable a structural description of their elements such as the objects, relationships, and activities. In the time dimension the graph models all the temporal phases of the future besides the past and present in a comprehensive manner, and all the spatial aspects in an intuitive but efficient fashion. The overall architecture composing the Physical Layer, Logical Layer and Conceptual Layer which are integrated according to their interrelations allows events occurring in their corresponding worlds to be simulated in historical context. The S-T Graph could be used both to simulate the situations in the virtual world and to realize the knowledge systems of the virtual inhabitants to be used in judging and evaluating those situations. By adding temporal changes to the multi-layered architecture of our virtual world, this model lays a foundation for maximizing the diversity of situations in the simulation of a virtual world.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.1
• /
• pp.62-69
• /
• 2015

Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.

• Journal of the Korean Ceramic Society
• /
• v.39 no.3
• /
• pp.294-298
• /
• 2002

Polycrystalline $La_{2.1}Sr_{1.9}Mn_3O_{10}$ with layered perovskite structure have been successfully synthesized and investigated with respect to their thermoelectric, electric and magnetic properties. The large magnetoresistance (MR) effect with $-{\Delta}{\rho}/{\rho}_0$ of ∼120% at 0.85T was observed in a wide temperature range below a cusp temperature in resistivity of about 120K, which is well below the magnetic $T_C$. At high temperature, a singnificant difference between the activation energy deduced from the electrical resistivity and thermoelectric power, a characteristic of small polaron, is observed. All of the experimental data can be well explained on the basis of the small polaron model.

• Journal of Korean Medicine Rehabilitation
• /
• v.24 no.3
• /
• pp.111-119
• /
• 2014

Objectives This study aims to analyze a thermal distribution in biological living tissue during warm needling therapy by using a finite element method. The analysis provides an understanding of warm needling's efficacy and safety. Methods A model which consisted of four-layered tissue and stainless steel needle was adopted to analyze the thermal distribution in living tissue with a bioheat transfer analysis. The governing equation for the analysis was a Pennes' bioheat equation. A heat source characteristic of warm needling therapy was obtained by previous experimental measurements. The first analysis of the time-dependent temperature distribution was conducted through points on a boundary between the needle and the tissue. The second analysis was conducted to visualize the horizontal temperature distribution. Results When heat source's peak temperatures was above $500^{\circ}C$ and temperature rising rates were relatively slow, the peak temperature at skin surface exceeded a threshold of pain and tissue damage ($45^{\circ}C$), whereas when the peak temperature was around $400^{\circ}C$, the peak temperature at the skin surface was within a safe limit. In addition, the conduction of combustion energy from the moxa was limited to the skin layer around the needle. Conclusions The results suggest that the skin layer around the needle can be heated effectively by warm needling therapy, but it appears to have little effect at the deeper tissue. These findings enhance our understanding of the efficacy and the safety of the warm needling therapy.

• Food Science and Biotechnology
• /
• v.17 no.5
• /
• pp.925-930
• /
• 2008

Norovirus has become the most common cause of human gastroenteritis in developed countries. Detection procedures of foodborne viruses from foods require several steps. The concentration step using polyethylene glycol (PEG) is time-consuming and the detection efficiency of reverse transcription-polymerase chain reaction (RT-PCR) is affected by inhibitors from food components. In this study, a rapid detection method based on buoyant density centrifugation was developed to replace the time-consuming chloroform-polyethylene glycol-Tris Tween method. Feline calicivirus that belongs to the family Caliciviridae was used as a surrogate model for norovirus. After artificial inoculation of feline calcivirus (FCV) to oyster and lettuce, 830 ${\mu}L$ of homogenized sample suspension was layered on the top of 670 ${\mu}L$ 20% percoll and centrifuged. Then RNA extraction step was proceeded with the supernatant. By varying several physical conditions, the detection limits were lowered to $2.4{\times}10^2$ PFU per 1 g in oyster and $2.4{\times}10^0$ PFU per 1 g in lettuce. The protocol obtained in this study could be used to develop new detection method for norovirus in foods.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.579-582
• /
• 2009

With the aid of the increasing interests of Context-aware Augmented Reality Agent (AR Agent), various researches of AR Agent have been performed to explore the possibility of the agent as novel interface and the entity responding autonomously by user's input. However, in previous works, AR Agents are lack of specific method for using various contextual information. To revolve around those problems, we propose the Behavior Generation System for Context-aware AR Agent using layered architecture. Based on Belief-Desire-Intention (BDI) model and Hierarchical Task Network (HTN) searching, the sequence of agent behavior has been selected in behavior planning layer. Then, the agent evaluates appropriateness of behaviors using previous behavior and the type of input before activation. This behavior generation system can be applied for edutainment, game, and assistant agent, which need intuitive and effective behaviors to convey information. Through this research, we expect that the Context-aware AR Agent could support for not only information delivery, but also the capability of effective communication for user.