• Magazine of the Korea Concrete Institute
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• v.6 no.6
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• pp.159-172
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• 1994

The relmund hammer test and ultrasonic pulse velocity test methods are commonly used to determine the in-situ compressive strength of concrete. One of the special feature of these methods is that they cannot give consistent and reliable results for variety of structures. In particular, very old existing structures have been generally received sreious environmental affectsand thus the strength prediction will be different from normal structures. The purpose of the present study is, therefore, to propose realistic equations to predict the in-situ strengths of actual old concrete structures. The rebound hammer and ultrasonic pulse velocity tests, carbonation depth measurments and core compressive strength measurements have been carried out for very old hydraulic and seacoast concrete structures spanning from one to about seventy years in age. From these test results, the strength-rebound number relations, the strength-pluse velocity relatinns and the strength-rebound number-pluse velocity relations have been obtained through multiple regression analysis. The present study indicates that the existing equations by nondestructive tests give quite different results from the present data. The proposed equations reasonably well predict the measured data for old concrete structures, especially for low strength concrete. The prediction equations proposed here can be efficiently used in determining the in-situ strength of old concrete structures.

• The Journal of Engineering Geology
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• v.7 no.2
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• pp.151-159
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• 1997

Since healed microcracks in quartz grain of grantic rocks within the same mass have identical preferred orientations, the oreintations of granitic cores may be determined if the distinctive feature of healed microcracks can be used.In this study, the possibility of determining orientations of granitic cores using healed microcrack orientations were examined using samples from the borehole drilled to 200 m in depth at the Hongcheon. Eight sections whose core recoveries are 100% were selected. Two to six samples were collected in each section and orientations of healed microcracks in each sample were measured. Healed microcracks in samples from each section show almost identical orientations. The error range for sections with only one preferred orientations is within $\pm$5$^{\circ}$, indicating that correct orientations of core can be determined. However, orientations of cores in sections which have 2 or more healed microcrack orientations should be determined using orientations as well as distribution of peaks of orientations. The error range for this case is lager than former one and is within $\pm$15$^{\circ}$. The orientations of joint which is very impontant factor for designing tunnel and slope stability can be determined using healed microcrack orientation in cores.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.201-211
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• 2013

In this paper, we propose a hand tracking and gesture recognition system. Our system employs a depth capture device to obtain 3D geometric information of user's bare hand. In particular, we build a flexible tracking volume and restrict the hand tracking area, so that we can avoid diverse problems caused by conventional object detection/tracking systems. The proposed system computes running average of the hand position, and tracking volume is actively adjusted according to the statistical information that is computed on the basis of uncertainty of the user's hand motion in the 3D space. Once the position of user's hand is obtained, then the system attempts to detect stretched fingers to recognize finger gesture of the user's hand. In order to test the proposed framework, we built a NUI system using the proposed technique, and verified that our system presents very stable performance even in the case that multiple objects exist simultaneously in the crowded environment, as well as in the situation that the scene is occluded temporarily. We also verified that our system ensures running speed of 24-30 frames per second throughout the experiments.

• Korean journal of communication and information
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• v.60
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• pp.52-74
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• 2012

Legislation needs to be understood within a political, societal relationship among lawmaking bodies rather than by legal provision itself. In order to examine features and functions of communication in the process of legislation, this study conducted focus group interviews with experts as well as in-depth individual interviews. The result of this research as follows: First, the study found that although the domestic legislative process has been made by active interactions among lawmaking subjects, it was hard to conclude that this procedure is providing effective and productive legislative agenda because of chaotic communications made along the process. Second, the study found that national legislative process has been gradually moving, although restricted, to an open political space, the National Assembly, from a closed space, the executive branch. Third, the study found a remarkable feature including growing influence of experts groups and civic organizations in the legislative process. It is a significant change that legislative staff such as National Assembly aides, investigators, expert committeemen and deputy director generals played a role of "insiders," unnoticeably influencing the legislative process, and that civic organizations and NGOs, which have been excluded in the previous legislative processes, emerged as a new influencing circle in the process. Lastly, the study found that media organizations, in the process of developing agenda, had a strong impact on the National Assembly as a subject forming public issues and as a messenger of the legislative agenda while they played a limited role in affecting the government. This study discusses why communication in the domestic legislative process is important and what are some hindering and facilitating factors in the process.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.55-65
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• 2016

Detecting an object which is located at seabed is an important issue for various areas. This paper presents an approach to detection of an object that is placed at seabed in the shallow water. A conventional scheme is to employ a side-scan sonar to obtain images of a detection area and to use image processing schemes to recognize an object. Since this approach relies on high frequency signals to get clear images, its detection range becomes shorter and the processing time is getting longer. In this paper, we consider an active sonar system that is repeatedly sending a linear frequency modulated signal of 6~20 kHz in the shallow water of 100m depth. The proposed approach is to model consecutively received reflected signals and to measure their modeling error magnitudes which decide the existence of an object placed on seabed depending on relative magnitude with respect to threshold value. The feature of this approach is to only require an assumption that the seabed consists of an homogeneous sediment, and not to require a prior information on the specific properties of the sediment. We verify the proposed approach in terms of detection probability through computer simulation.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.402-414
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• 2012

This study investigated the effects of the instructions using analogies in learning the concept of saturated solution by the analogy presentation types and the verbal learning styles upon the mapping understanding, the mapping errors, and the perceptions of the instruction. Fifth graders (N=123) at an elementary school were selected and assigned to VA (n=63) and VPA (n=60) groups. As a pretest, a test on the verbal learning style was administered. The students in the VA group learned the target concept with a verbal analogy, while those in the VPA group learned it with a verbal/pictorial analogy. After the students learned it, a mapping understanding test was administered. The students in the VPA group also administered the test on the perceptions of the instruction and some of them were interviewed in depth. The results revealed that the scores of the students with strong verbal learning preference in the VPA group were significantly lower than those in the VA group in the mapping understanding test. However, the scores of the students with weak verbal learning preference were not significantly different between the two groups. Five types of mapping errors were identified: failure to map, mismapping, rash mapping, impossible mapping, and mapping of a surficial feature. According to students' verbal learning styles, there were some differences in the frequencies of mapping errors in the two groups. Many students in the VPA group, regardless of their verbal learning styles, had positive perceptions of the instruction in various cognitive and motivational aspects. However, some of them also pointed out a few difficulties of the instruction. Educational implications of these findings are discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.230-237
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• 2000

An ecological study of the benthic macrofauna was carried out using a modified van Veen grab in September 1997, in Namdaechon estuary, Yangyang, Korea. A total of 17 macro-invertebrates was collected and examined from eleven stations in the study area, including 3,795 individuals and 738.63 g wet weight. Arthropods, annelids and molluscs were most abundant and occupied more than $95{\%}$ of the total number of species, individuals and biomass. Namdaechon estuary in Yangyang was very poor in macrobenthic biodiversity, and numerically dominated and characterized by the polychaetes Heteromastus filiformis, Hediste japonica, Eteone longa, an unidentified oligochaete Oligochaeta sp., a corbulid bivalve Corbicula japonica, and an estuarine isopod Cyathura higoensis. Species composition, species dominance, density, and species evenness were compared among stations. The macrofaunal azoic zone appeared in the bottom of 7 m in depth nearby the artificial bank to catch the salmons to return to the livers for spawning. It probably resulted from the oxygen depletion following strong stratification in summer, which can cause major effect on the ecological conditions and then finally kill bottom macro-invertebrates in this area. Moreover, some opportunistic species thrived in nearby another station and this is of vital importance in terms of the ecological succession in a benthic polluted area.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.337-344
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• 2006

In this paper, we describe the design and the implementation of word clustering system using a definition of an entry word in the dictionary, called a dictionary definition. Generally word clustering needs various features like words and the performance of a system for the word clustering depends on using some kinds of features. Dictionary definition describes the meaning of an entry in detail, but words in the dictionary definition are implicative or abstractive, and then its length is not long. The word clustering using only features extracted from the dictionary definition results in a lots of small-size clusters. In order to make large-size clusters and improve the performance, we need to transform the features into more general words with keeping the original meaning of the dictionary definition as intact as possible. In this paper, we propose two methods for extending the dictionary definition using ontology. One is to extend the dictionary definition to parent words on the ontology and the other is to extend the dictionary definition to some words in fixed depth from the root of the ontology. Through our experiments, we have observed that the proposed systems outperform that without extending features, and the latter's extending method overtakes the former's extending method in performance. We have also observed that verbs are very useful in extending features in the case of word clustering.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.747-761
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• 2008

In order to experiment the acoustic remote classification of seabed sediment, we achieved ground-truth data(i.e. video and grab samples, etc.) and developed post-processing for automatic classification procedure on the basis of 300 kHz MultiBeam Echo Sounder(MBES) backscattering data, which was acquired using KONGBERG Simrad EM3000 at Sock-Cho Port, East Sea of South Korea. Sonar signal and its classification performance were identified with geo-referenced video imagery with the aid of GIS (Geographic Information System). The depth range of research site was from 5 m to 22.7 m, and the backscattering amplitude showed from -36dB to -15dB. The mean grain sizes of sediment from equi-distanced sampling site(50 m interval) varied from 2.86$(\phi)$ to 0.88(\phi). To acquire the main feature for the seabed classification from backscattering amplitude of MBES, we evaluated the correlation factors between the backscattering amplitude and properties of sediment samples. The performance of seabed remote classification proposed was evaluated with comparing the correlation of human expert segmentation to automatic algorithm results. The cross-model perception error ratio on automatic classification algorithm shows 8.95% at rocky bottoms, and 2.06% at the area representing low mean grain size.

• The Journal of the Petrological Society of Korea
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• v.25 no.2
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• pp.121-142
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• 2016

The Satkatbong pluton was studied with other plutons together, but some fundamental petrological characteristics were missing. This study mainly reports the petrography and geochemistry of the Satkatbong pluton comparing with the Daebo and the Bulguksa granitoids in south Korea. The Satkatbong pluton, which is host rock including a number of Mafic Magmatic Enclaves (MME), is north-south shaped dioritic pluton, located along the east coast of south Korea. The Satkatbong pluton seems to be unconformable with Cretaceous sedimentary rocks from fieldwork result. In geochemistry, the Satkatbong pluton, which is roughly similar with the Daebo granitoids, is classified into calc-alkali series rock and volcanic arc granitoid Tectonically. The fact that AlT value in marginal parts of amphiboles in the Satkatbong pluton is lower than other granitoids implies emplacement depth of the Satkatbong pluton was relatively shallow. The Satkatbong pluton shows different geochemical feature compared to the adjacent adakitic Yeongdeok granite. This seems to be caused by mafic mantle material expected from the occurrence of MMEs.