• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.4
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• pp.387-400
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• 2013

In this study, the slope stability analysis and the landslide hazard assessment in tunnel portal slope were carried out. First, we selected highly vulnerable areas to slope failure using the slope stability analysis and analyzed the slope failure scale. According to analyses results, high vulnerable area to slope failure is located at 485~495 m above sea level. The slope is stable in a dry condition, while it becomes unstable in rainfall condition. The analysis results of slope failure scale show that the depth of slope failure is maximum 2.1 m and the length of slope failure is 18.6 m toward the dip direction of slope. Second, we developed a 3-D simulation program to analyze characteristics of runout behavior of debris flow. The developed program was applied to highly vulnerable areas to slope failure. The result of 3-D simulation shows that debris flow moves toward the central part of the valley with the movement direction of landslide from the upper part to the lower part of the slope. 3-D simulation shows that debris flow moves down to the bottom of mountain slope with a speed of 7.74 m/s and may make damage to the tunnel portal directly after 10 seconds from slope failure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.9-20
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• 1991

The characteristics of the unconsolidated sediment in Gwangyang bay was analyzed from the core samples. The porosity of the sediment showed irregular variation with respect to the sedimentation depth, which indicated that sediment weight-induced consolidation was not significant. Numerical analysis for the mechanical and hydraulic behavior of the unconsolidated sediment due to the tidal sea level change was processed. Because of the delayed excessive pore pressure change in the very low permeable mud medium, the magnitude of the excessive pore pressure for the duration of the minimum sea level exceeded the total stress from the sea water weight, which resulted in the negative (tensional) effective stress below the top surface. The in-situ effective stress, obtained by superposing the tensional effective stress on the solid weight-induced compressive stress, was remained to be tensile (quick-sand condition) near the top surface of the mud deposit. The occurrence of the quirk-sand condition provided a theoretical evidence for the insignificant consolidation and the irregular porosity variation of the sediment. When the sand is distributed on the top surface of the mud layer, the quick-sand condition occurred below the sandy mud layer and the downward movement of sand particles was facilitated.

• Journal of Environmental Impact Assessment
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• v.29 no.3
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• pp.182-197
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• 2020

This study investigated the home range and characteristics of activities to contribute to the improvement of management techniques and the successful promotion of management policies of invasive nutria, which is a representative invasive species of South Korea. Six individuals were captivated for the study. Remote radio tracking on three of them was carried out followed by the analysis of the results. The average home range of the follow-up individuals were confirmed to be 0.043 ㎢ at MCP 95%, 0.085 ㎢ at K 95%. It was 0.018 ㎢ at K 50%, which is the core space. In 95% MCP, males exhibited the home range with 0.058 ㎢, showed wider home range 0.046 ㎢ than females who showed 0.012 ㎢, and showed a wider home range 0.015 ㎢ more at night than during the day. As a result of comparing the results of this study with the case studies of overseas studies, it is determined that the magnitude of the derived home range is the result of a stable habitat in which the procurement of food resources is smooth and human interference is limited. The daily moved distance of males was larger than that of females, with a maximum moved distance of 1,278 m per day. Activity at the study site is high from around sunset to around 6 A.M., 10 P.M., 7 P.M., 1 A.M., and 5 A.M., and high around sunrise and low during the daytime such as 2 P.M., which reflected the propensity of nocturnal animals to act. The results of this study on the home range and activity in nutria can be used as useful data forimproving the management of invasive alien species for the installation and operation of traps, the spatial setting of controlled areas, and the calculation of the amount ofresources together with a basic understanding of nutria's behaviors in South Korea.

• The Journal of Engineering Geology
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• v.15 no.1
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• pp.29-39
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• 2005

For detecting a ground contamination survey, soil sampling method have been used a drilling or coring technique in general. However these methods are very difficult to systematically real-time monitoring of variation of contamination degree in field. ]'n this research frequency Domain Reflectometry (FDR) system was suggested and carried out to experimental approaches for determination of oil contamination on surface and underground. Experimental method using FDR method was discussed with feasibility of measurement in the laboratory column test. It is determined to degree of oil contamination due to response of dielectric constant re-lated with volumetric water content(θ/sub w/) and volumetric oil content( θ/sub al/ ) of saturated and unsaturated soil media. And physical properties such as effective porosity and oil residual ratio of saturated soil media were also measured through real-time monitoring works using installed FDR measurement sensors, which are defected characteristics of oil movement in the saturated soil media under the soil column tests. In the results of these experiments, a range of effective porosity was estimated to about 0.35 compared with initial porosity 0.40 of manufactured saturated soil media, which is also calculated to about 87.5% to the ratio of initial porosity to effective porosity. Finally oil residual ratio which is compared with volumetric water content and volumetric oil content was calculated about 62.5%.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.201-209
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• 2002

Crib wall system is one of segmental crib type wall. Crib walls are constructed from separate members with no bonds between them other than frictional. The wall units are divide into two main types termed headers and stretchers. The headers run from the front to the back of the wall, perpendicular to the wall face. The cells are created by forming a grid by stacking individual wall components known as headers and stretchers. The body of wall consists of a system of open cell which are filled with a granular material. The design of crib retaining wall is usually based on conventional design methods derived from Rankine and Coulomb theory so that is able to resist the thrust of soil behind it, because it may be assumed that the wall acts as a rigid body. However, deformation characteristics of crib walls cannot be assumed as monolithic. They consist of individual members which have been stacked to creat a three dimensional grid. Therefore, the segmental grid allows relative movement between the individual member within the wall. The three dimensional flexible grid leads to stress distribution by interaction behavior between soil and crib wall. Therefore, in this study, in order to analysis the trends of deflection of crib wall system, new numerical models based on the results of Brandl's full scale test are introduced for design concept.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.4 s.31
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• pp.35-43
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• 2004

Multibeam Echosounder system is the latest technology of a hydrographic survey utilized in producing an electronic nautical chart, obtaining a DEM with high precision, making a moving image by Swath surveying a wide area. As a fundamental study for improving the precision of MBES, we compared and analyzed measurements of DGPS and Motion sensor, and studied for the dynamic characteristics of vessel's movements. DGPS was installed in front and in the rear and on both side or the vessel and surveyed. The receiving precision of surveyed GPS results was obtained to the satisfactory extent that was possible to valuate the accuracy of Motion sensor as 0.0016$^{\circ}$ of the roll value and 0.0009$^{\circ}$ of the pitch value. The relationship between the values of heading, pitch, and roll in Motion sensor and the data of DGPS was proportional correlation. In addition, it is considered that deviations by elements like rapid turning and vibration of the vessel will be occurred, although the correlation of each deviation according to each amount or change is proportional. It is suitable that GPS installs in the central line of the vessel that is less affected than other places by waving because the amount of change in the tide level obtained from GPS survey and the value of heave are similar with the values taken by Motion sensor, and the velocity of GPS is different from installed places. The accuracy of the final result from MBES could be affected by the values of gyro and Motion sensor inputted to MBES processor because there were intervals of 15s and 13s of receiving time in gyro and Motion sensor respectively compared with the real-time measurements of DGPS.

• Korean Institute of Interior Design Journal
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• v.23 no.1
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• pp.61-68
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• 2014

Recently, there have been increasing attempts to pursue and express feelings such as sensibilities, emotions, and impressiveness in commercial spaces. One of such methods is to apply 'storytelling' to space designs. Applicability of storytelling to a space suggests that the contents of a space can be expressed through various mediums. Portraying events and situations through a single time continuity of a story is referred to as 'narrative'. The movement of users and sequence of contents are determined by a narrative. It provides different storytelling and a sense of place to each space through various roles, such as wide association, engraving, and image formation. A narrative can lead users to engage in different perceptions and behaviors even in spaces with the same content. Thus, this study is intended to examine the impact of space marketing in line with design narratives, assuming that narratives of commercial space designs will influence the formation of brand identity. The research methods are as follows. First, the definition of narratives in space design was established by examining narrative architectures. Second, design analysis tools for commercial spaces were established from the perspective of narratives through preceding studies. Third, the design narratives of different shops under the same brand were comparatively analyzed through a case study. To carry out a case study, a commercial space of 'O'sulloc' was selected, and its brand identity was studied from the narrative standpoint. The case study involved interior designs of 7 road shops of 'O'sulloc.' Among the 7 road shops, two of them with the biggest difference in design narratives were selected, and an observation survey was done on the users as a second analysis. Through the observation survey, actual design narrative experience was analyzed in 4 steps of introduction, development, turn, and conclusion. The findings are as follows. The design method of each shop varied, and different design elements were emphasized. Among various elements, the ones that reflect the brand identity of 'O'sulloc' the best were logo, product, and shape. During the process of narratives, the characteristics of each shop and user recognition and behavior varied depending on the degree of emphasis on a particular element. It suggests that space design narratives can influence the formation of brand identity. This study provides ideal directions of developing space designs necessary for forming brand identity from the standpoint of Korean traditional culture modernization. Future studies could discuss the economic feasibility of such designs.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.140-149
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• 2018

Along with the recent increase in national income, social phenomena such as aging due to a decrease in population and an increase in single households are observed. There are also an increasing number of households raising pets in proportion to aging households and the increase in the number of single households, most of which use animal companions to overcome loneliness and boost domestic vitality. As more and more people consider pets as family members, the size of the domestic pet market is also growing. The growing number of pets in older households and single households is not properly managed by care such as food meals and exercise management for pets. It is necessary to research and develop robots that can monitor animal companions remotely, feed a certain amount of food at regular intervals, and manage their health through exercise. Among pet companions, dog selection is the highest. Therefore, this study identified robot research on driving methods, examples of existing pet care systems, and researched pet care robots using obstacle avoidance algorithms. In order to use the snack pay behavior and obstacle avoidance algorithm of the pet animals by applying IoT and we .oPI technology, it is able to use ultrasonic sensors on the front and has four infrared sensors on the back. However, this study does not reflect the characteristics of other pet animals as a study on pet care robots, and it requires continuous observation and testing.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.107-119
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• 2023

The technology that recognizes a soldier's motion and movement status has recently attracted large attention as a combination of wearable technology and artificial intelligence, which is expected to upend the paradigm of troop management. The accuracy of state determination should be maintained at a high-end level to make sure of the expected vital functions both in a training situation; an evaluation and solution provision for each individual's motion, and in a combat situation; overall enhancement in managing troops. However, when input data is given as a timer series or sequence, existing feedforward networks would show overt limitations in maximizing classification performance. Since human behavior data (3-axis accelerations and 3-axis angular velocities) handled for military motion recognition requires the process of analyzing its time-dependent characteristics, this study proposes a high-performance data-driven classifier which utilizes the long-short term memory to identify the order dependence of acquired data, learning to classify eight representative military operations (Sitting, Standing, Walking, Running, Ascending, Descending, Low Crawl, and High Crawl). Since the accuracy is highly dependent on a network's learning conditions and variables, manual adjustment may neither be cost-effective nor guarantee optimal results during learning. Therefore, in this study, we optimized hyperparameters using Bayesian optimization for maximized generalization performance. As a result, the final architecture could reduce the error rate by 62.56% compared to the existing network with a similar number of learnable parameters, with the final accuracy of 98.39% for various military operations.

• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.87-102
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• 1991

It has been reported that the failure of Carsington Dam in Eng1and occured due to the existence of a thin yellow clay layer which was not identified during the design work, and due to pre-existing shears of the clay layer. The slope stability analyses during the design work, which utilized traditional circular arc type failure method and neglected the existence of the clay layer, showed a safety factor of 1.4. However, the post-failure analyses which utilized translational failure mode considering the clay layer and the pre-existing shear deformation revealed the reduction of safety factor to unity. The post-failure analysis assumed 10。 inclination of the horizontal forces onto each slice based on the results of finite element analyses. In this paper, Bishop's simplified method, Janbu method, and Morgenstern-Price method were used for the comparison of both circular and translational failure analysis methods. The effects of the pre-existing shears and subsquent movement were also considered by varying the soil strength parameters and the pore pressure ratio according to the given soi1 parameters. The results showed factor of safefy 1.387 by Bishop's simplified method(STABL) which assumed circular arc failure surface and disregarding yellow clay layer and pre-failure material properties. Also the results showed factor of safety 1.093 by Janbu method(STABL) and 0.969 by Morgenstern-Price method(MALE) which assumed wedge failure surface and considerd yellow clay layer using post failure material properties. In addition, dam behavior was simulated by Cam-Clay model FEM program. The effects of pore pressure changes with loading and consolidation, and strength reduction near or at failure were also considered based on properly assumed stress-strain relationship and pore pressure characteristics. The results showed that the failure was initiated at the yellow clay layer and propagated through other zones by showing that stress and displacement were concentrated at the yel1ow clay layer.