• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.1
• /
• pp.13-26
• /
• 2023

Recently, as the development of underground spaces has become active due to rapid urbanization and population density, interest in the ground behavior according to the construction of underground spaces is increasing. In large cities with high population density and many buildings, ground subsidence has a great impact on structures and there may be a risk of collapse, so the analysis of ground behavior due to underground construction is essential. Previous studies have been conducted on the subsidence pattern of the surface and the deformation of the tunnel when constructing the tunnel, but analysis has rarely been conducted by using actual topographic information. Therefore, this study analyzed the difference in ground behavior between the actual topography and the flat topography. As a result, it was confirmed that ground settlement occurs at higher elevations, such as in mountainous topography, and when the numerical analysis is performed considering topographical information, the crown settlement of the tunnel is up to about approx. It showed a difference of 10 mm, and it was found that the sensitivity was less in the case of displacement of tunnel wall compared to the crown settlement and ground settlement. The numerical analysis considering the actual GIS-based topographic information presented in this study can be used to obtain more accurate surface subsidence data to understand the behavior of the upper structure due to tunnel excavation.

• Journal of the Korean Geosynthetics Society
• /
• v.22 no.1
• /
• pp.87-96
• /
• 2023

There are a lot of difference between the surface settlement and the differential settlement measured at the Busan New Port, where the dredged and reclaimed clay layer exists and below the clay is originally thickly distributed. To find the cause and solution of this, the actual conditions of each differential settlement used for the soft ground improvement, characteristics, installation method, measurement frequency, measurement data management, and data analysis of each type were considered. In the deep soft ground improvement work where large deformation occurs, the bending deformation of the screw-type differential settlement gauge is less than that of other types of measuring instruments, so there is less risk of loss, and the reliability of data is relatively high as the instruments are installed by drilling for each stratum. Since the greater the amount of high-precision settlement measurement data, the higher the settlement analysis precision. It is necessary to manage with higher criteria than the measurement frequency suggested in the standard specification. For the data management of the differential settlement gauge, it is desirable to create graphs of the settlement and embankment height of the relevant section over time, such as surface, differential, and settlement of pore water pressure gauge for each point. In the case of multi-layered ground with different compression characteristics, it is more appropriate to perform settlement analysis by calculating the consolidation characteristics of each stratum using a differential settlement data.

• 한국체육학회지인문사회과학편
• /
• v.55 no.3
• /
• pp.543-551
• /
• 2016

The study was aimed at investigating the relationship between biomechanical properties of cervical muscles and smartphone addiction score in fifty healthy males using smartphone more than 60 minutes each day. The usage of smartphone was evaluated by smartphone addiction survey developed from Korean International Society Agency. Biomechanical properties of three major cervical muscles; splenius capitis, sternocleidomastoid and upper trapezius, were measured by Myoton, and conducted five parameters; frequency, decrement, stiffness, creep, and relaxation time. As results, all parameters had less than 2% of coefficient of variation(CV) between measurement intervals. Also, intra-class correlation coefficient(ICC) indicated a high reliability(ICC>.9, p<.01). Moreover, the smartphone addiction score was significantly different in frequency(r=.353, p<.05) and stiffness(r=.346, p<.05) on upper trapezius; in addition, in decrement(r=-.284, p<.05) and creep(r=.288, p<.05) on sternocleidomastoid. Especially, splenius capitis was closely related with the overuse of smartphone(frequency, r=-.368, p<.01; decrement, r=-.405, p<.01; stiffness, r=-.424, p<.01). In conclusion, this study implied that the overuse of smartphone is significantly related with the damage of cervical muscles, cervical pain, and headache; furthermore, Myoton can be used as an effective device to assess mechanical properties of cervical muscles.

• Geophysics and Geophysical Exploration
• /
• v.26 no.4
• /
• pp.171-184
• /
• 2023

Machine learning (ML)-based cavity detection using a large amount of survey data obtained from vehicle-mounted ground penetrating radar (GPR) has been actively studied to identify underground cavities. However, only simple image processing techniques have been used for preprocessing the ML input, and many conventional seismic and GPR data processing techniques, which have been used for decades, have not been fully exploited. In this study, based on the idea that a cavity can be identified using diffraction, we applied ML-based diffraction separation to GPR data to increase the accuracy of cavity detection using the YOLO v5 model. The original ML-based seismic diffraction separation technique was modified, and the separated diffraction image was used as the input to train the cavity detection model. The performance of the proposed method was verified using public GPR data released by the Seoul Metropolitan Government. Underground cavities and objects were more accurately detected using separated diffraction images. In the future, the proposed method can be useful in various fields in which GPR surveys are used.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.1
• /
• pp.32-49
• /
• 1998

For estimation of regional myocardial blood flow with O-15 water PET, a few modifications considering partial volume effect based on single compartment model have been proposed. In this study, we attempted to quantify the degree of heterogeneity and to show the effect of tissue flow heterogeneity on partition coefficient(${\lambda}$) and to find the relation between perfusable tissue index(PTI) and ${\lambda}$ by computer simulation using two modified models. We simulated tissue curves for the regions with homogeneous and heterogeneous blood flow over a various flow range(0.2-4.0ml/g/min). Simulated heterogeneous tissue composed of 4 subregions of the same or different size of block which have different homogeneous flow and different degree of slope of distribution of blood flow. We measured the index representing heterogeneity of distribution of blood flow for each heterogeneous tissue by the constitution heterogeneity(CH). For model I, we assumed that tissue recovery coefficient ($F_{MME}$) was the product of partial volume effect($F_{MMF}$) and PTI. Using model I, PTI, flow, and $F_{MM}$ were estimated. For model II, we assumed that partition coefficient was another variable which could represent tissue characteristics of heterogeneity of flow distribution. Using model II, PTI, flow and ${\lambda}$ were estimated. For the simulated tissue with homogeneous flow, both models gave exactly the same estimates, of three parameters. For the simulated tissue with heterogeneous flow distribution, in model I, flow and $F_{MM}$ were correctly estimated as CH was increased moderately. In model II, flow and ${\lambda}$ were decreased curvi-linearly as CH was increased. The degree of underestimation of ${\lambda}$ obtained using model II, was correlated with CH. The degree of underestimation of flow was dependent on the degree of underestimation of ${\lambda}$. PTI was somewhat overestimated and did not change according to CH. We conclude that estimated ${\lambda}$ reflect the degree of tissue heterogeneity of flow distribution. We could use the degree of underestimation of ${\lambda}$ to find the characteristic heterogeneity of tissue flow and use ${\lambda}$ to recover the underestimated flow.

• Korean Journal of Remote Sensing
• /
• v.38 no.2
• /
• pp.139-151
• /
• 2022

SAGD (Steam-Assisted Gravity Drainage) method is widely used for oil recovery in oil sands regions. The SAGD operation causes surface displacement, which can affect the stability of oil recovery plants and trigger various geological disasters. Therefore, it isimportant to monitor the surface displacement due to SAGD in the oil sands region. In this study, the surface displacement due to SAGD operations of the Athabasca oil sands region in Alberta, Canada, was observed by applying Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) technique to the Sentinel-1 time series SAR data acquired from 2016 to 2021. We also investigated the construction and expansion of SAGD facilitiesfrom Landsat-7/8 time seriesimages, from which the characteristics of the surface displacement according to the oil production activity of SAGD were analyzed. Uplift rates of 0.3-2.5 cm/yr in the direction of line of sight were observed over the SAGDs and their vicinity, whereas subsidence rates of -0.3--0.6 cm/yr were observed in areas more than several kilometers away from the SAGDs and not affected by oil recovery activities. Through the analysis of Landsat-7/8 images, we could confirm that the SAGDs operating after 2012 and showing high oil production activity caused uplift rates greater than 1.6 cm/yr due to the subsurface steam injection. Meanwhile, very small uplift rates of several mm per year occurred over SAGDs which have been operated for a longer period of time and show relatively low oil production activity. This was probably due to the compression of reservoir sandstone due to continuous oil recovery. The subsidence observed in areas except for the SAGDs and their vicinity estimated to be a gradual land subsidence caused by melting of the permafrost. Considering the subsidence, it was expected that the uplift due to SAGD operation would be greater than that observed by the PSInSAR. The results of this study confirm that the PSInSAR can be used as an effective means for evaluating productivity and stability of SAGD in the extreme cold regions.

• Cartoon and Animation Studies
• /
• s.42
• /
• pp.25-52
• /
• 2016

Animation documentary is a hybrid genre that is newly highlighted with opposite properties. The actual world is reproduced with an unrealistic method in documentary aspect, but the objectivity of documentaries cannot be guaranteed as the boundary of actual pictures and digital images has become ambiguous. As the animation documentary by Ari Folman succeeded in 2008, the focus of this study is on 'how can fictional animations prove the authenticity of documentaries?' in which the study is mainly conducted in documentary aspect. For this, the researcher considers visual style research has important role in understanding and developing a new video genre, and asserts the necessity of research on reproduction image that is produced by the characteristics of animation which is produced in frame units. This paper has contents on the visual style of animation documentaries with pictorial reproduction methods in which animation images were classified into 3 styles based on previous research on animation documentary style. Visual styles are classified into actual image that is based on similarity with reality to deliver objective facts, image that is transformed through emphasis and omission which are factors of animations, and surrealistic image that reproduces non-visual regions such as illusions and the inner side of characters. Through this study that analyzes visual style types and characteristics, animation documentaries are expected to position as a hybrid genre that illustrates reality with a new method instead of being included in the existing reproduction method of documentaries.

• Journal of Science of Art and Design
• /
• v.13 no.1
• /
• pp.61-86
• /
• 2008

Buddhism and Buddhist art originated in India, but when they were introduced to different countries, they created an international environment. Buddhism was introduced as cultural package, with written texts, visual images, rituals, and the organization of monasteries. Buddhist art originated in India during the reign of King Asoka and then was developed under the political, intellectual, artistic, religious, social and natural environments of the regions. The stupa and the chaitya halls create monastic environment. The natural environment of the trade routes and caravans in the Central Asian deserts preserved brilliant-colored murals and helped spread tram India to China. When Buddhism and Buddhist art were introduced to China, Korea, and Japan, Buddhism became a part of government institution and social organization. Gigantic statues were carved in caves in mountains for political purposes. The Chinese transformed the stupa into a square pillar and created pagodas with tiled roofs in tower forms. Koreans not only transmitted the Buddhist art from China to Japan, but it also changed it with originality in the iconography of the pensive bodhisattva images and in the architecture of Seoggulam. The official ideology of Neo Confucian philosophy brought the rise of Chan Buddhism. Zen monasteries in Japan created unique environments by establishing the Zen Buddhist garden. to prompt believers to meditate. An important development in Buddhist art is the Esoteric Buddhist art in China and Tibet. This category belongs to the intellectual, religious as well as artistic environments. The Tibetan deities with consorts in their embrace symbolize the union of the god and the devotees. Buddhist art created a unique environment that was spread out to many nations and changed greatly over time.

• Tunnel and Underground Space
• /
• v.15 no.2 s.55
• /
• pp.119-128
• /
• 2005

Although the evaluation of the mechanical properties and behavior of jointed rock masses is very important for the design of tunnel and underground openings, it has always been considered the most difficult problem. One of the difficulties in describing the rock mass behavior is the selection of the appropriate constitutive model. This limitation may be overcome with the progress in discrete element software such as PFC, which does not need the user to prescribe a constitutive model for rock mass. In this paper, a 30\;m\;\times\;30\;m\;\times\;30\;m m jointed rock mass of road tunnel site was analyzed. h discrete fracture network was developed from the joint geometry obtained from core logging and surface survey. Using the discontinuities geometry from the DFN model, PFC simulations were carried out, starting with the intact rock and systematically adding the joints and the stress-strain response was recorded for each case. With the stress-strain response curves, the mechanical properties of jointed rock masses were determined. As expected, the presence of joints had a pronounced effect on mechanical properties of the rock mass. More importantly, getting the mechanical response of the PFC model doesn't require a user specified constitutive model.

• Korean Journal of Ecology and Environment
• /
• v.56 no.1
• /
• pp.70-82
• /
• 2023

Recently, Korean government has introduced Multi Metric Indices (MMI) using various biocommunity information for aquatic ecosystem monitoring and ecosystem health assessment at the national level. MMI is a key tool in national ecosystem health assessment programs. The MMI consists of indices that respond to different target environmental factors, including environmental disturbance (e.g. nutrients, hydrological and hydraulic situation of site etc.). We used zooplankton community information collected from Korean lakes to estimate the availability of candidate zooplankton MMI indices that can be used to assess lake ecosystem health. First, we modified the candidate indices proposed by the U.S. EPA to suit Korean conditions. The modified indices were subjected to individual index suitability analysis, correlation analysis with environmental variables, and redundancy analysis among indices, and 19 indices were finally selected. Taxonomic diversity was suggested to be an important indicator for all three taxonomic groups (cladoceran, copepod, rotifer), on the other hand, the indices using biomass for large cladocerans and copepods, while the indices using abundance were suggested for small cladocerans and rotifers.