• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.246-260
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• 2014

A 90-m horizontal-resolution numerical model was configured to study the micrometeorological features of local winds in the valley of Gwangneung KoFlux (Korea Flux network) Sites (GDK: Gwangneung Deciduous forest site in Korea, GCK: Gwangneung Coniferous forest site in Korea) during summer days. The U. S. Geological Survey (USGS) Shuttle Radar Topography Mission (SRTM) data were employed for high-resolution model terrain height. Model performance was evaluated by comparing observed and simulated near-surface temperature and winds. Detailed qualitative analysis of the model-simulated wind field was carried out for two selected cases which are a clear day (Case I) and a cloudy day (Case II). Observed winds exhibited that GDK and GCK, as well as Case I and Case II, had differences in timing, duration and strength of daytime and nighttime wind direction and speeds. The model simulation results strongly supported the existence of the drainage flow in the valley of the KoFlux tower sites. Overall, the simulated model fields realistically presented the diurnal cycle of local winds in and around the valley, including the morning drainage-upslope transition and the evening reversal of upslope wind. Also, they indicated the complexity of local winds interactions by presenting that daytime westerly winds in the valley were not always pure mountain winds and were often coupled with larger-scale wind systems, such as synoptic-scale winds or mesoscale sea breezes blowing from the west coast of the peninsula.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.3
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• pp.459-475
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• 2008

This study analyzes the network structure of the Metropolitan Seoul subway system by applying complex network analysis methods. For the purpose, we construct the Metropolitan Seoul subway system as a network graph, and then calculate various indices introduced in complex network analysis. Structural characteristics of Metropolitan Seoul subway network are discussed by these indices. In particular, this study determines the shortest paths between nodes based on the weighted distance (physical and time distance) as well as topological network distance, since urban travel movements are more sensitive for them. We introduce an accessibility measurement based on the shortest distance both in terms of physical distance and network distance, and then compare the spatial structure between two. Accessibility levels of the system have been getting up overall, and thus the accessibility gaps have been getting lessen between center located subway stops and remote ones during the last 10 years. Passenger traffic volumes are explored from real passenger transaction databases by utilizing data mining techniques, and mapped by GIS. Clear differences reveal between the spatial patterns of real passenger flows and accessibility. That is, passenger flows of the Metropolitan Seoul subway system are related with population distribution and land use around subway stops as well as the accessibility supported by the subway network.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.819-826
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• 2018

The generalized Hamming weight is one of the important parameters of the linear code. It determines the performance of the code when the linear codes are applied to a cryptographic system. In addition, when the block code is decoded by soft decision using the lattice diagram, it becomes a measure for evaluating the state complexity required for the implementation. In particular, a bit-parallel multiplier on finite fields based on trinomials have been studied. Cellular automata(CA) has superior randomness over LFSR due to its ability to update its state simultaneously by local interaction. In this paper, we deal with the efficient synthesis of the pseudo random number generator, which is one of the important factors in the design of effective cryptosystem. We analyze the property of the characteristic polynomial of the simple 90/150 transition rule block, and propose a synthesis algorithm of the reversible 90/150 CA corresponding to the trinomials $x^2^n+x^{2^n-1}+1$($n{\geq}2$) and the 90/150 reversible CA(RCA) corresponding to the maximum weight polynomial with $2^n$ degree by using this rule block.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2715-2720
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• 2014

Median filtering is very effective to remove impulse type noises, so it has been widely used in many signal processing applications. However, due to the time complexity of its non-linearity, median filtering is often used using a small filter window size. A lot of work has been done on devising fast median filtering algorithms, but most of them can be efficiently applied to input data with finite integer values like images. Little work has been carried out on fast 2-d median filtering algorithms that can deal with real-valued 2-d data. In this paper, a fast and simple median 2-d filter is presented, and its performance is compared with the Matlab's 2-d median filter and a heap-based 2-d median filter. The proposed algorithm is shown to be much faster than the Matlab's 2-d median filter and consistently faster than the heap-based algorithm that is much more complicated than the proposed one. Also, a more efficient median filtering scheme for 2-d real valued data with a finite range of values is presented that uses higher-bit integer 2-d median filtering with negligible quantization errors.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.47-56
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• 2012

The purpose of this study is to test the effect of pedagogical agent realism and expertise on persona effect. There were two perspectives of the pedagogical agents' social interaction. Self-identification hypothesis argues that complexity of agent image is better to increase social interaction. Subjective identification insists that simplified image is more helpful to facilitate social interaction. However, from the cognitive load theory perspective, learners' expertise can be a major factor to determine persona effect. Sixty-eight college students (male=19 and female=49) participated. The independent variables were the degree of realism of pedagogical agent (detailed vs. simplified image) and the expertise (high prior knowledge group vs. low prior knowledge group). The dependant variables were comprehension test and the agent persona instrument (API). There was no significant difference in comprehension test score; however, there were significant interaction effect on the most constructs of API: 1) facilitating of learning, 2) credible, and 3) human-like. The follow-up analysis of simple main effect revealed that high expertise group showed significantly higher perception of the three construct with high realism of pedagogical agent. The results of study show that learners' expertise plays a key role of perception of persona effect.

• Archives of design research
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• v.19 no.2 s.64
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• pp.121-128
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• 2006

The elements to enhance preference in symbol design are mainly related to consumers' response and aesthetic elements. Because certain aesthetic elements in design affect consumers' response and it is actually presented through (the different level of) preference. This study through surveying case studies examines whether a certain aesthetic element in symbol design gives rise to much preference. According to the result of study, high preference in symbolic design depends on high level of Rhythm, Balance, Harmony, Elaboration, Round, Gestalt, Organic, and Artificial/Natural among aesthetic elements. In comparison, it is founded that Simplicity/complexity, Objective/Abstract, depth, and symmetry should be designed at the moderate level, and proportion, repetition of elements be at the low level. Additionally(or Besides) this study makes out that symbol design cases with high preference have shapes from natural material or patterns of traditional culture, while cases with low preference have shapes from geometric figures. On the basis of these results, a guideline of symbol design could De offered(or suggested) to fit preference of consumers. But, this study is mostly concerned with only affect among emotional reactions of consumer in a scope of study, and is considered only in the aspect of form excluding color and texture.

• Archives of design research
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• v.18 no.3 s.61
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• pp.95-104
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• 2005

Although the volume and complexity of available information have increased, our ability to process such volume of complex information has not been met with corresponding development. Information designers have been given the responsibility to address such unbalanced progress by developing effective visual systems to deliver and communicate such information to the masses in a manner that is quick and easy to process and understand. This study originated in recognition of these issues. This study seeks to find a solution to these issues in rhetorics in order to proliferate visual communications in recognition of the increasing importance of information and visual communication. Rhetorics, a field of study with a long history of analyzing the delivery of communication, provides numerous possibilities for the re-establishment of importance placed on visual information communication. Included in this study are (i) a thorough analysis of the principals of expression and logic offered by rhetorics, as applicable to information design (ii) a proposal to the solution to the above-mentioned issues encompassing the rhetoric process and methods of expression of information design and (iii) the practical application of these design principals to social activities. In order to provide an example of the practical use of the rhetoric methodology Presented in this study, we applied the rhetoric methodology to the 'Information Design for Public Transportation of Seoul.' and developed a new map and a guidebook. The raw data necessary for the foregoing were obtained through the analysis of the information designs that are currently in use in connection with mass transportation in Seoul and the survey evaluation conducted among Seoul residents. We modulated the infrastructure of Seoul by using 48 TAZs, computed the routes that are most likely to be used, and proposed the predictable information analysis process. The design proposed on this study encompasses color coding and use of combined information, and application of style and sequential information analysis process.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.4 s.27
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• pp.21-27
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• 2003

The rational polynomial coefficients(RPC) model is a generalized sensor model that is used as an alternative for the physical sensor model for IKONOS-2 and QuickBird. As the number of sensors increases along with greater complexity, and as the need for standard sensor model has become important, the applicability of the RPC model is also increasing. The RPC model can be substituted for all sensor models, such as the projective camera the linear pushbroom sensor and the SAR This paper is aimed at generating a RPC model from the physical sensor model of the KOMPSAT-1(Korean Multi-Purpose Satellite) and aerial photography. The KOMPSAT-1 collects $510{\sim}730nm$ panchromatic images with a ground sample distance (GSD) of 6.6m and a swath width of 17 km by pushbroom scanning. We generated the RPC from a physical sensor model of KOMPSAT-1 and aerial photography. The iterative least square solution based on Levenberg-Marquardt algorithm is used to estimate the RPC. In addition, data normalization and regularization are applied to improve the accuracy and minimize noise. And the accuracy of the test was evaluated based on the 2-D image coordinates. From this test, we were able to find that the RPC model is suitable for both KOMPSAT-1 and aerial photography.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.81-87
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• 2016

It is important to analyze the exact damage information for fast recovery when natural disasters cause damage on river-side facilities such as dams, bridges, embankments etc. In this study, we shows the method to effectively damage analysis plan using UAV(Unmanned aerial vehicle) images and accuracy assessment of it. The UAV images are captured on area near the river-side facilities and the core methodology for damage analysis are image matching and change detection algorithm. The result(point cloud) from image matching is to construct 3-dimensional data using by 2-dimensional images, it extracts damage areas by comparing the height values on same area with reference data. The results are tested absolute locational precision compared by post-processed aerial LiDAR data named reference data. The assessment analysis test shows our matching results 10-20 centimeter level precision if external orientation parameters are very accurate. This study shows suggested method is very useful for damage analysis in a large size structure like river-side facilities. But the complexity building can't apply this method, it need to the other method for damage analysis.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.11
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• pp.593-606
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• 2016

Computer simulation is widely used in a variety of computational science and engineering fields, including computational fluid dynamics, nano physics, computational chemistry, structural dynamics, and computer-aided optimal design, to simulate the behavior of a system. As the demand for the accuracy and complexity of the simulation grows, however, the cost of executing the simulation is rapidly increasing. It, therefore, is very important to lower the total execution time of the simulation especially when that simulation makes a huge number of repetitions with varying values of input parameters. In this paper we develop a simulation service system that provides the ability to predict the result of the requested simulation without actual execution for that simulation: by recording and then returning previously obtained or predicted results of that simulation. To achieve the goal of avoiding repetitive simulation, the system provides two main functionalities: (1) storing simulation-result records into database and (2) predicting from the database the result of a requested simulation using statistical machine learning techniques. In our experiments we evaluate the prediction performance of the system using real airfoil simulation result data. Our system on average showed a very low error rate at a minimum of 0.9% for a certain output variable. Using the system any user can receive the predicted outcome of her simulation promptly without actually running it, which would otherwise impose a heavy burden on computing and storage resources.