• Structural Engineering and Mechanics
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• v.89 no.6
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• pp.617-626
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• 2024

The study investigated the behavior of plain and fibered Ultra-High Performance Concrete (UHPC) beams under varying loading conditions using integrated analysis of the flexure and acoustic emission tests. The loading rate of testing is -0.25 -2 mm/min. It is observed that on increasing loading rate, flexural strength increases, and toughness decreases. The acoustic emission testing revealed that higher loading rates accelerate crack propagation. Fiber effect and matrix cracking are identified as significant contributors to the release of acoustic emission energy, with fiber rupture/failure and matrix cracking showing rate-dependent behavior. Crack classification analysis indicated that the rise angle (RA) value decreased under quasi-static loading. The average frequency (AF) value increased with the loading rate, but this trend reversed under rate-dependent conditions. K-means analysis identified distinct clusters of crack types with unique frequency and duration characteristics at different loading rates. Furthermore, the historic index and signal strength decreased with increasing loading rate after peak capacity, while the severity index increased in the post-peak zone, indicating more severe damage. The sudden rise in the historic index and cumulative signal strength indicates the possibility of several occurrences, such as the emergence of a significant crack, shifts in cracking modes, abrupt failure, or notable fiber debonding/pull-out. Moreover, there is a distinct rise in the number of AE knees corresponding to the increase in loading rate. The crack mapping from acoustic emission testing aligned with observed failure patterns, validating its use in structural health monitoring.

• Korean Journal of Remote Sensing
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• v.38 no.6_3
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• pp.1827-1836
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• 2022

Disasters that occur unexpectedly are difficult to predict. In addition, the scale and damage are increasing compared to the past. Sometimes one disaster can develop into another disaster. Among the four stages of disaster management, search and rescue are carried out in the response stage when an emergency occurs. Therefore, personnel such as firefighters who are put into the scene are put in at a lot of risk. In this respect, in the initial response process at the disaster site, robots are a technology with high potential to reduce damage to human life and property. In addition, Light Detection And Ranging (LiDAR) can acquire a relatively wide range of 3D information using a laser. Due to its high accuracy and precision, it is a very useful sensor when considering the characteristics of a disaster site. Therefore, in this study, development and experiments were conducted so that the robot could perform real-time monitoring at the disaster site. Multi-sensor module was developed by combining LiDAR, Inertial Measurement Unit (IMU) sensor, and computing board. Then, this module was mounted on the robot, and a customized Simultaneous Localization and Mapping (SLAM) algorithm was developed. A method for stably mounting a multi-sensor module to a robot to maintain optimal accuracy at disaster sites was studied. And to check the performance of the module, SLAM was tested inside the disaster building, and various SLAM algorithms and distance comparisons were performed. As a result, PackSLAM developed in this study showed lower error compared to other algorithms, showing the possibility of application in disaster sites. In the future, in order to further enhance usability at disaster sites, various experiments will be conducted by establishing a rough terrain environment with many obstacles.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.26-41
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• 2012

It is necessary to manage, forecast and prepare agricultural production based on accurate and up-to-date information in order to cope with the climate change and its impacts such as global warming, floods and droughts. This study examined the applicability as well as challenges of the object-based image analysis method for developing a land cover image classification algorithm, which can support the fast thematic mapping of wide agricultural areas on a regional scale. In order to test the applicability of RapidEye's multi-temporal spectral information for differentiating agricultural land cover types, the integration of other GIS data was minimized. Under this circumstance, the land cover classification accuracy at the study area of Kimje ($1300km^2$) was 80.3%. The geometric resolution of RapidEye, 6.5m showed the possibility to derive the spatial features of agricultural land use generally cultivated on a small scale in Korea. The object-based image analysis method can realize the expert knowledge in various ways during the classification process, so that the application of spectral image information can be optimized. An additional advantage is that the already developed classification algorithm can be stored, edited with variables in detail with regard to analytical purpose, and may be applied to other images as well as other regions. However, the segmentation process, which is fundamental for the object-based image classification, often cannot be explained quantitatively. Therefore, it is necessary to draw the best results based on expert's empirical and scientific knowledge.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.525-533
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• 2019

There are two feature collection methods in digital mapping using the UAV (Unmanned Aerial Vehicle) Photogrammetry: vectorization and stereo plotting. In vectorization, planar information is extracted from orthomosaics and elevation value obtained from a DSM (Digital Surface Model) or a DEM (Digital Elevation Model). However, the exact determination of the positional accuracy of 3D features such as ground facilities and buildings is very ambiguous, because the accuracy of vectorizing results has been mainly analyzed using only check points placed on the ground. Thus, this study aims to review the possibility of 3D spatial information acquisition and digital map production of vectorization by analyzing the corner point coordinates of different layers as well as check points. To this end, images were taken by a Phantom 4 (DJI) with 3.6 cm of GSD (Ground Sample Distance) at altitude of 90 m. The outcomes indicate that the horizontal RMSE (Root Mean Square Error) of vectorization method is 0.045 cm, which was calculated from residuals at check point compared with those of the field survey results. It is therefore possible to produce a digital topographic (plane) map of 1:1,000 scale using ortho images. On the other hand, the three-dimensional accuracy of vectorization was 0.068~0.162 m in horizontal and 0.090~1.840 m in vertical RMSE. It is thus difficult to obtain 3D spatial information and 1:1,000 digital map production by using vectorization due to a large error in elevation.

• Archives of design research
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• v.19 no.1 s.63
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• pp.317-328
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• 2006

So far, the behaviors of Web users have been predicted or analyzed mostly by their demographic characteristics or by considering in which context they gain access to that. But now there is a question about whether those characteristics are the only factors to trigger their use of Web. If the answer is not affirmative, what types of additional factors could cause such an action and how they characterize it should be discussed. User profile information has been considered one of the crucial elements to define user characteristics in user-centered UI design sector, and in order to apply it to UI design, it's needed to meditate on the above-mentioned questions. In this study, it's first attempted to have a good understanding of the users of different media and to review existing user classification methods. Next, user classification variables and relevant scales were prepared to sort out users according to their type of using Web, and case study was conducted to identify the behavioral characteristics of users and classify them according to their behavioral features. Finally, the user profile features of individual user groups were figured out based on data that were gathered by making an experiment, and data mapping was fulfilled between the behavioral characteristics and user profile characteristics to find out what types of behaviors were caused by the characteristics of user profile. As a result, it's found that user characteristics could have an impact on not only their general information and relevant contexts but their attitude of using different media and personality type. There were some problems with the experimental design, but more accurate information on the relationship of user behaviors to user profile characteristics will be obtained if those problems are eliminated. As user behaviors could be predicted only by user profile characteristics, user classification is expected to make a contribution to enhancing the efficiency of UI design.

• Economic and Environmental Geology
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• v.36 no.3
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• pp.243-255
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• 2003

The mathematical models for GIS-based spatial data integration have been developed for geological applications such as mineral potential mapping or landslide susceptibility analysis. Among various models, the effectiveness of fuzzy logic based integration of multiple sets of geological data is investigated and discussed. Unlike a traditional target-driven fuzzy integration approach, we propose a data-driven approach that is derived from statistical relationships between the integration target and related spatial geological data. The proposed approach consists of four analytical steps; data representation, fuzzy combination, defuzzification and validation. For data representation, the fuzzy membership functions based on the likelihood ratio functions are proposed. To integrate them, the fuzzy inference network is designed that can combine a variety of different fuzzy operators. Defuzzification is carried out to effectively visualize the relative possibility levels from the integrated results. Finally, a validation approach based on the spatial partitioning of integration targets is proposed to quantitatively compare various fuzzy integration maps and obtain a meaningful interpretation with respect to future events. The effectiveness and some suggestions of the schemes proposed here are illustrated by describing a case study for landslide susceptibility analysis. The case study demonstrates that the proposed schemes can effectively identify areas that are susceptible to landslides and ${\gamma}$ operator shows the better prediction power than the results using max and min operators from the validation procedure.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.397-405
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• 2015

Currently, Korea's digital maps are being produced through traditional aerial photogrammetry methods. Aerial photogrammetry is the most economical way to produce a map of a wide area. However, timely survey is not allowed depends on weather condition and it is inefficient for small area surveying in economic point of view. Therefore, it costs too much and needs long time to produce a map for various small areas where are terrestrial changes for updating the map. In contrast, UAV photogrammetry is possible to work even in cloudy weather because of shooting at low altitude below the clouds. It also has excellent mobility and shoot quickly and well suited for small-scale mapping in several places by low cost. In this study, we produced an ortho-photo and digital map with the UAV photogrammetry method using SIFT and SfM algorithm and verified its accuracy to evaluate the applicability for future digital map updates. The accuracy was verified by comparing the results of the ground survey for check points selected on the digital map. Test results show small errors at ±2.6cm in X coordinates, ±2.8cm in Y coordinates and ±5.8cm in height and we could find a possibility that UAV photogrammetry would be fully applicable for digital map updating.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.169-177
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• 2009

In this paper, we propose a new shot boundary detection method which is optimized for news video story parsing. This new news shot boundary detection method was designed to satisfy all the following requirements: 1) minimizing the incorrect data in data set for anchor shot detection by improving the recall ratio 2) detecting abrupt cuts and gradual transitions with one single algorithm so as to divide news video into shots with one scan of data set; 3) classifying shots into static or dynamic, therefore, reducing the search space for the subsequent stage of anchor shot detection. The proposed method, based on singular value decomposition with incremental clustering and mercer kernel, has additional desirable features. Applying singular value decomposition, the noise or trivial variations in the video sequence are removed. Therefore, the separability is improved. Mercer kernel improves the possibility of detection of shots which is not separable in input space by mapping data to high dimensional feature space. The experimental results illustrated the superiority of the proposed method with respect to recall criteria and search space reduction for anchor shot detection.

• Korea Journal of Hospital Management
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• v.6 no.3
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• pp.5-24
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• 2001

The purpose of this study was to serve as a basis for providing quality medical service and mapping out consumer-centered marketing strategies to successfully cope with the rapidly changing medical environment and meet consumer needs, by examining what affected the satisfaction and revisit of health Promotion center Client. The subjects in this study were 186 of visitor to health Promotion center in a university hospital in the city of Busan. A survey was conducted with structured questionnaire from March 2 to 30, 2001. The collected data were analyzed with SPSS for Windows (ver10.0). For more statistical analysis, frequency analysis, component analysis, t-test, ANOVA and correlation analysis procedures were utilized. Results of the study can be summarized as follows: 1. Regarding demographic characteristics, 51.6% of the Client investigated were male, and 48.4% were female. The greatest number of them were in their 40s(38.9%). 86.5% were married, and 34.2% were self-employed. 44% were a high-school graduate, and the monthly mean income of 59.4% was one to three million Won. And, the residential area of 46.8%, the largest percentage, was a half-an-hour distance from health Promotion center. 2. The most common motivation of their selection of the health Promotion center was a recommendation by Staff and neighborhood(59.7%), followed by excellent facilities and services(17.2%), the tradition and reputation of the hospital(7.5%), and its publicity pamphlets(7.5%). 3. 45.9%, the largest percentage, acquired health-related information from their friends or acquaintances. 43.8%, the greatest percentage, visited there because they felt there's something wrong with their body. 53.4% worried about the possibility of being attacked by cancer, and 57.5% wanted to take a precise cancer examination. For health maintenance, 50.1% got regular exercise. Regular exercise was considered most crucial for health maintenance or promotion. 4. The largest reason they used that examination center again was the kindness of employees(52.7%), followed by the tradition and reputation of the hospital(21%) and excellent examination setting and equipment(10.8%). 5. By demographic factor, there was no significant difference between the man and women in satisfaction level with examination and expenses. The women expressed more satisfaction at facilities, and the high-school graduate group were more contented with expenses. 6. As a result of investigating their satisfaction level according to the motivation of selecting that examination center, the group that chose the center due to excellent facilities and services were more satisfied with examination and expenses. 7. As for the relationship of total examination satisfaction to revisit. intention, there was a higher correlational relationship between total health examination satisfaction and expense satisfaction. Especially, the more they were satisfied with examination, the more they were willing to revisit there for another examination.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.454-461
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• 2015

This study aims to classify the biotope types based on the vegetation community in built-up areas by different land use and to map the plant communities. By classifying biotopes according to a taxonomic system, the characteristics of a biological community can be well-represented. The biotope classification indexes for the target area include human behavioral factors such as land use intensity, land-use patterns and land-cover types. The type classification was divided into four hierarchic ranks starting with Biotope Class, next by Biotope Group and Biotope Type and lastly by Biotope Sub-Type. The Biotope Class was first divided into two areas: the areas improved by humans and the areas unimproved by humans. The improved areas were again divided into permeable and non-permeable regions on the Biotope Group level. In the Biotope Type level, permeable paving areas were divided into areas with wide gap pavers and those with narrow gap pavers. The differential species of each biotope type are Lindera glauca, Conyza canadensis, Mazus pumilus, Vicia tetrasperma, Crepidiastrum sonchifolium, Zoysis japonica, Potentilla supina and Festuca arundinacea. The results of this study suggest that the biotope classification methodology, using a subjective phytosociological approach, is a useful and valuable tool and the results also suggest the possibility of applying more objective and scientific methods in mapping and classifying various environments.