• Journal of the Korean earth science society
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• v.37 no.4
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• pp.218-229
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• 2016

The bedform stability diagram indicates the shape and size of bedforms that will occur to a given grain size and flow velocity. The diagram has been constructed from experimental data which have been mostly acquired by flume experiments. Generally, the flume experiments have been performed on well sorted sediments with unimodal grain size distribution, in order to understand relationship between grain size and flow velocity. According to the diagram, a ripple structure initiates to be formed from lower flow regime flat bed, as the flow velocity increases on the surface of fine-sand or medium-sand sediments. This study aims to verify that the experimental result of bedform stability diagram will be reproduced in our flume experimental systems, and also to confirm that the result is consistent not only on well-sorted sand sediments but also on poorly-sorted sand sediments with bimodal grain size distribution. The experimental results in this study show that initiation of 2D or 3D ripple structure on poorly-sorted sand sediments requires higher flow velocity and shear stress than those for initiation of the structure on well-sorted sand sediments. In general, carbonate sediments are characterized by poor sorting due to inactive hydraulic sorting and bimodal grain size distribution with allochems and matrices. The results suggest that the carbonate depositional system possibly need a higher flow velocity for initial formation of 2D or 3D bedform structures. The reason might be the fact that pulling off and lifting of a grain in poorly sorted sediments require more energy due to sorting, friction, stabilization, armour effects, and their complex interaction. This preliminary study warrants additional experiments under various conditions and more accurate analysis on the relationship between formation of bedforms and grain size distribution.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.287-293
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• 2015

This study proposed signal processing techniques and neural network with weighted fuzzy membership functions(NEWFM) to detect epileptic seizure from EEG signals. This study used wavelet transform(WT), sequential increment method, and phase space reconstruction(PSR) as signal processing techniques. In the first step of signal processing techniques, wavelet coefficients were extracted from EEG signals using the WT. In the second step, sequential increment method was used to extract peaks from the wavelet coefficients. In the third step, 3D diagram was produced from the extracted peaks using the PSR. The Euclidean distances and statistical methods were used to extract 16 features used as inputs for NEWFM. The proposed methodology shows that accuracy, specificity, and sensitivity are 97.5%, 100%, 95% with 16 features, respectively.

• Journal of the Korea Computer Graphics Society
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• v.7 no.2
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• pp.11-19
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• 2001

This paper proposes a colored paper mosaic rendering technique based on image segmentation that can automatically generate torn and tagged colored paper mosaic effect. and 3D effect that come about in human-made mosaic work can be represented by generating shadow using difference of paper thickness. Previous method did not produce satisfactory results due to the ineffectiveness of having to use pieces of the same size. The proposed two methods for determination of paper shape and location that are based on segmentation can subdivide image area by considering characteristics of image. The first method is to generate Voronoi polygon after subdividing the segmented image again using quad tree. And the second method is to apply the Voronoi diagram on each segmentation layer. Through these methods, the characteristic of the image is expressed in more detail than previous colored paper mosaic rendering method and these methods enable to produce image that is closer to human-made mosaic work.

• Journal of Broadcast Engineering
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• v.4 no.2
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• pp.155-163
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• 1999

In this paper, we propose novel scene change detection and key frame selection techniques, which use two feature images, i.e., DC and edge images, extracted directly from MPEG compressed video. For fast edge image extraction. we suggest to utilize 5 lower AC coefficients of each DCT. Based on this scheme, we present another edge image extraction technique using AC prediction. Although the former is superior to the latter in terms of visual quality, both methods all can extract important edge features well. Simulation results indicate that scene changes such as cut. fades, and dissolves can be correctly detected by using the edge energy diagram obtained from edge images and histograms from DC images. In addition. we find that our edge images are comparable to those obtained in the spatial domain while keeping much lower computational cost. And based on HVS, a key frame of each scene can also be selected. In comparison with an existing method using optical flow. our scheme can select semantic key frames because we only use the above edge and DC images.

• Spatial Information Research
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• v.22 no.6
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• pp.55-65
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• 2014

By combining the role of current GIS technology and design behaviors from the cognitive perspective, spatial conceptualization can be extended efficiently and creatively for ill-structured problems. This study elaborates the model of a conceptualization-oriented SDSS(Spatial Decision Support System) for a landscape design problem. Current information-oriented GIS technology plays a minor role in planning and design. The three attributes in planning and design problems describe how the deficiencies of current GIS technology can be seen as a failure of the technology. These are summarized: (1) Information Explosion/Information Ignorance (2) Dilemma of Rigor and Relevance (3) Ill-structured Nature of planning and Design. In order to implement the conceptualization idea in the current GIS environment, it will be necessary to shift from traditional, information-oriented GISs to conceptualization-oriented SDSSs. The conceptualization-oriented SDSS model reflects the key elements of six important theories and techniques. The six useful theories and techniques are as follows; (1) Human Information Processing (2) Tool/Theory Interaction (3) The Sciences of the Artificial and Epistemology of Practice (4) Decision Support Systems (DSSs) (5) Human-Computer Interaction (HCI) (6) Creative Thinking. The future conceptualization-oriented SDSS can provide capabilities for planners and designers to figure out some "hidden organizations" in spatial planning and design, and develop new ideas through its conceptualization capability. The facilitation of conceptualization has been demonstrated by presenting three key ideas for the framework of the SDSS model: (1) bubble-oriented design support system (2) prototypes as an extension of semantic memory, and (3) scripts as an extension of episodic memory in a cognitive pschology perspective. The three ideas can provide a direction for the future GIS technology in planning and design.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.5
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• pp.1-15
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• 2001

Expressing complex query conditions in a concise and intuitive way has been a challenge in the design of visual object-oriented query languages. We propose a visual query language called VOQL (Visual Object oriented Query Language) for object oriented databases. By employing the visual notation of graph and Venn diagram, the database schema and the advanced features of object oriented queries such as multi-valued path expressions and quantifiers can be represented in a simple way. VOQL has such good features as simple and intuitive syntax, well-defined semantics, and excellent expressive power of object-oriented queries compared with previous visual object-oriented query languages.

• Journal of IKEEE
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• v.22 no.2
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• pp.488-490
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• 2018

In this study, we propose newly designed feedback field-effect transistors that utilize the positive feedback of charge carriers in single-gated silicon channels to achieve steep switching behaviors. The band diagram, I-V characterisitcs, subthreshold swing, and on/off current ratio are analyzed using a commercial device simulator. To demonstrate the changing characteristics of hysteresis, one of the important features of the feedback field effect transistor, we simulated changing the gate insulating material and the gate metal electrode. The fluctuation in the characteristics changed the $V_{TH}$ of the hysteresis and showed a decrease in width of the hysteresis.

• Journal of Engineering Education Research
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• v.24 no.1
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• pp.3-14
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• 2021

The purpose of this study is to analyze the characteristics of efficient problem-solving teams and inefficient problem-solving teams using SYMLOG. In this study, 35 college students majoring in engineering education at C university were organized into 7 teams and carried out technological problem solving projects over one semester. Based on the results of the team project, the top 2 teams were defined as efficient problem solving teams and the bottom 2 teams were defined as inefficient problem solving team, and analyzed the characteristics of the team using SYMLOG. The main results are as follows: First, an analysis of SYMLOG from efficient problem solving teams and inefficient problem solving teams showed that there was a difference between self-awareness and others' perception in terms of U(Upward)-D(Downward) dimension. Second, in the inefficient problem solving teams, there was a significant difference between self-awareness and others' in the F(Forward)-B(Backward) dimension. Third, there was no difference between self-awareness and others' in both efficient and inefficient teams at the P (Positive)-N(Negative) dimension. Fourth, an efficient problem-solving team had a clear leader, and there was a team member who supported the leader. On the other hand, the inefficient problem-solving team did not have a clear leader, or one person played the role of leader and there were no team members supporting the leader.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.235-247
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• 2009

In order to elucidate the cause of Cochlodinium polykrikoides blooms in the Korea southern coastal water, we investigated observational data of water temperatures and salinities in summer and winter, obtained from the stoppage of ship by NFRDI (National Fisheries Research and Development Institute) as well as composite images by NOAA from 1995 to 2008. Cochlodinium polykrikoides blooms occurred when water temperature was approximately $25.0{\sim}26.0^{\circ}C$ and salinity was 31.00 psu on average in Narodo neighboring seas. Different thermohaline fronts were observed between the Korea southern coastal water and the open sea water in summer and winter, respectively. That is, in winter four fronts were observed between the Korea southern coastal water with low temperature and low salinity, intermediate water originated from Tsushima Warm Current, Tsushima Warm Current with high temperature and high salinity, and the China coastal water with low temperature and low salinity. In contrast, in summer two fronts were observed between the Korea southern coastal water with low temperature and high salinity, Tsushima Warm Current with high temperature and low salinity, and the China coastal water with high temperature and high salinity. These thermohaline fronts also proved to be formed by two water masses with a different physical property, in terms of T-S diagrams. Consequently, we noticed that C. polykrikoides blooms occurring in Narodo neighboring seas in summer had a close relationship with thermohaline fronts observed between the Korea southern coastal water and Tsushima Warm Current.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.135-142
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• 2013

Contour detection is important for many computer vision applications, such as shape discrimination and object recognition. In many cases, local luminance changes turn out to be stronger in textured areas than on object contours. Therefore, local edge features, which only look at a small neighborhood of each pixel, cannot be reliable indicators of the presence of a contour, and some global analysis is needed. The novelty of this operator is that dilation is limited to Deluanary triangular. An efficient implementation is presented. The grouping algorithm is then embedded in a multi-threshold contour detector. At each threshold level, small groups of edges are removed, and contours are completed by means of a generalized reconstruction from markers. Both qualitative and quantitative comparison with existing approaches prove the superiority of the proposed contour detector in terms of larger amount of suppressed texture and more effective detection of low-contrast contour.