• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.3
• /
• pp.320-326
• /
• 2017

Multistage deep-drawing technology is used widely in the production of mobile phone battery cases to improve productivity and economy. To ensure adequate capacity and rigidity, such cases are fabricated as a rectangular cup with a high slender ratio. The multistage deep-drawing of a rectangular cup entails a high slender ratio, and the heights of the product sides may be non-uniform because of the complicated deformation mechanisms. This causes problems in product assembly that affects the surface quality of the case. This study examined a blank shape that minimizes the height variations of the product to resolve the aforementioned problems. Optimization design and analysis were performed to identify the shape that yields the least variation. The long and short sides of an oval blank were set as the design variables. The objective function was set to yield the lowest height difference, and the thickness reduction rate of the product was set to the target range. In addition, the height of the final shape was set as a constraint. The height difference was minimized successfully using the optimized design. The design process of the initial blank for all rectangular shapes can be automated in the future.

• Journal of radiological science and technology
• /
• v.32 no.2
• /
• pp.195-203
• /
• 2009

Image registration is a fundamental task in image processing used to match two or more images. It gives new information to the radiologists by matching images from different modalities. The objective of this study is to develop 2D image registration algorithm for PET/CT and CT images acquired by different systems at different times. We matched two CT images first (one from standalone CT and the other from PET/CT) that contain affluent anatomical information. Then, we geometrically transformed PET image according to the results of transformation parameters calculated by the previous step. We have used Affine transform to match the target and reference images. For the similarity measure, mutual information was explored. Use of particle swarm algorithm optimized the performance by finding the best matched parameter set within a reasonable amount of time. The results show good agreements of the images between PET/CT and CT. We expect the proposed algorithm can be used not only for PET/CT and CT image registration but also for different multi-modality imaging systems such as SPECT/CT, MRI/PET and so on.

• Spatial Information Research
• /
• v.21 no.1
• /
• pp.63-73
• /
• 2013

Geographic features are reflected in satellite images, which contain characteristic elements. Information on changes can be obtained through a comparison of images taken at different times. If multi-temporal images can be classified through the use of an unsupervised method, this is likely to improve the accuracy of image classification and contribute to various applications. A rule-based image classification algorithm for automatic processing without human involvement has been developed, but it must be verified that its results are not affected by imperfect elements. In this study, Landsat images of Jeju Island were used to carry out a rule-based image classification. The application results were examined for complex cases, including the presence of clouds in the images, different photographed times, and the type of target area, such as city, mountain, or field. The presence of clouds did not affect calculations, and appropriate classification rules were applied, depending on the different photographed times. The expansion of the urban areas of Jeju and the increase of facilities such as vinyl greenhouses in Seoguipo were identified. Furthermore, space information changes and accurate classifications for Jeju Island were obtained. With the goal of performing high-quality unsupervised classifications, measures to generalize and improve the methods employed were searched for. The findings of this study could be used in time-series analyses of images for various applications, including urban development and environmental change monitoring.

• The Journal of Society for e-Business Studies
• /
• v.18 no.4
• /
• pp.45-65
• /
• 2013

A design file can get larger in size as the complexity of the target object increases. A large design file may reside in a large parallel computing system, such as cloud computing systems, and many designers may work concurrently on the same design file. In such a case, it is obvious that we need some kind of protection mechanism so that each user can access only the area of the file he or she is entitled to. Two approaches can be taken for this problem: one is the traditional access control mechanisms and the other encryption techniques. We take the latter approach to ensure the safety of the file even in public domain such as clouding systems, and in this paper, we suggest an encryption scheme for a file where the file is encrypted in multi-layer so that each user is allowed to access the file only at the layer for which the user has the proper access right. Each layer of the file is encrypted with different keys and these keys are exposed only to those who have the right access permit. The paper explains the necessary file format to achieve this goal and discusses the file manipulation functions to handle this new file format.

• The Journal of Korean Association of Computer Education
• /
• v.23 no.4
• /
• pp.1-11
• /
• 2020

The purpose of this study is to propose the direction of AI education in K-12 education through investigating and analyzing aspects of the purpose, content, and methods of AI education as the curriculum and teacher training factors. We collected and analyzed 9 papers as the primary literature and 11 domestic and foreign policy reports as the secondary literature. The collected literatures were analyzed by applying a descriptive reviews, and the implications were derived by analyzing the curriculum components and TPACK elements for multi-dimensional analysis. As a result of this study, AI education targets were divided into three steps: AI users, utilizer, and developers. In K-12 education, the user and utilizer stages are appropriate, and artificial intelligence literacy must be included for user education. Based on the current computing thinking ability and coding ability for utilizer education, the implication was derived that it is necessary to target the ability to create creative output by applying the functions of artificial intelligence. In addition to the pedagogical knowledge and the ability to use the platform, The teacher training is necessary because teachers need content knowledge such as problem-solving, reasoning, learning, perception, and some applied mathematics, cognitive / psychological / ethical of AI.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.22 no.4
• /
• pp.1-11
• /
• 2019

With the development of remote sensing sensor technology, it has become possible to acquire satellite images with various spectral information. In particular, since the hyperspectral image is composed of continuous and narrow spectral wavelength, it can be effectively used in various fields such as land cover classification, target detection, and environment monitoring. Change detection techniques using remote sensing data are generally performed through differences of data with same dimensions. Therefore, it has a disadvantage that it is difficult to apply to heterogeneous sensors having different dimensions. In this study, we have developed a change detection method applicable to hyperspectral image and high spat ial resolution satellite image with different dimensions, and confirmed the applicability of the change detection method between heterogeneous images. For the application of the change detection method, the dimension of hyperspectral image was reduced by using correlation analysis and principal component analysis, and the change detection algorithm used CVA. The ROC curve and the AUC were calculated using the reference data for the evaluation of change detection performance. Experimental results show that the change detection performance is higher when using the image generated by adequate dimensionality reduction than the case using the original hyperspectral image.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.17 no.4
• /
• pp.10-27
• /
• 2014

HAZUS-MH is a GIS-based computer program that estimates potential losses from multi-hazard phenomena: earthquakes, floods and hurricanes. With respect to seismic disaster, characteristics of a hypothetical or actual earthquake are entered into HAZUS. Then HAZUS estimates the intensity of ground shaking and calculates the correspondent losses. In this study, HAZUS was used as a part of the preparations of the future seismic events at a coastal plant facility area. To reliably characterize the target facility area, many geotechnical characteristics data were synthesized from the existing site investigation reports. And the buildings and facilities were sorted by analyzing their material and structural characteristics. In particular, the study area was divided into 17 blocks taking into account the situation of both land development and facility distribution. The ground conditions of blocks were categorized according to the site classification scheme for earthquake-resistant design. Moreover, seismic fragility curves of a main facilities were derived based on the numerical modeling and were incorporated into the database in HAZUS. The results estimated in the study area using HAZUS showed various seismic damage and loss potentials depending on site conditions and structural categories. This case study verified the usefulness of the HAZUS for estimating earthquake losses in coastal facility areas.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.2
• /
• pp.21-35
• /
• 2020

Vegetation information is a very important factor used in various fields such as urban planning, landscaping, water resources, and the environment. Vegetation varies according to canopy density or chlorophyll content, but vegetation vitality is not considered when classifying vegetation areas in previous studies. In this study, in order to satisfy various applied studies, a study was conducted to set a threshold value of vegetation index considering vegetation vitality. First, an eBee fixed-wing drone was equipped with a multi-spectral camera to construct optical and near-infrared orthomosaic images. Then, GIS calculation was performed for each orthomosaic image to calculate the NDVI, GNDVI, SAVI, and MSAVI vegetation index. In addition, the vegetation position of the target site was investigated through VRS survey, and the accuracy of each vegetation index was evaluated using vegetation vitality. As a result, the scenario in which the vegetation vitality point was selected as the vegetation area was higher in the classification accuracy of the vegetation index than the scenario in which the vegetation vitality point was slightly insufficient. In addition, the Kappa coefficient for each vegetation index calculated by overlapping with each site survey point was used to select the best threshold value of vegetation index for classifying vegetation by scenario. Therefore, the evaluation of vegetation index accuracy considering the vegetation vitality suggested in this study is expected to provide useful information for decision-making support in various business fields such as city planning in the future.

• Phonetics and Speech Sciences
• /
• v.5 no.2
• /
• pp.3-10
• /
• 2013

The purpose of this study is to analyze the acoustic characteristics of Korean alveolar sibilant sounds of children with cerebral palsy by acoustic analysis. Thirteen children with spastic cerebral palsy aging from 6 to 10 years old, were selected by an articulation test, and compared with a control group of thirty children. The meaningless monosyllable CV, disyllable VCV(/asa/) and frame sentence including target syllables CV were measured. C was from the /s, s'/, and V was from the set /a, i, u, ${\varepsilon}$, o, ɯ, ʌ/. Multi-Speech was used for data recording and analysis. As a result, the frication duration of lenis-glottalized alveolar sibilant of children with cerebral palsy was significantly shorter than that of the control group in CV, VCV and frame sentence. The vowel duration in the following lenis-glottalized alveolar sibilant of children with cerebral palsy was significantly longer than that of the control group in CV, VCV and frame sentence. The children with cerebral palsy showed frequency and intensity of friction intervals which were significantly lower than in the control group in CV, VCV and frame sentence. In the comparison of the lenis-glottalized alveolar sibilant by the children with cerebral palsy group's phonation types, the frication duration showed a significant difference between the phonation types in CV, VCV and between the phonetic contexts. The glottalized-sibilant was longer than the lenis-sibilant in all the phonetic contexts. The subsequent vowel duration showed a significant difference between the phonation types in VCV and between the phonetic contexts(p<.05). The vowel duration in the following glottalized-sibilant was longer than the vowel duration in the following lenis-sibilant in all the phonetic contexts. In the frequency there was a significant difference between the phonation types in CV, and in the intensity there was a significant difference between the phonation type in CV and VCV. The children with spastic cerebral palsy had difficulty in articulating the alveolar sibilant due to poor control ability in laryngeal, respiration and articulatory movements which require fine motor coordination. This study quantitatively analyzes the acoustic parameters of the alveolar sibilant in various phonetic contexts. Therefore, the results are expected to help provide fundamental data for an intervention of articulation treatment for children with cerebral palsy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.8 s.111
• /
• pp.773-787
• /
• 2006

An airborne radar is an essential aviation electronic system for the aircraft to perform various civil and/or military missions in all weather environments. This paper presents the design, development, and test results of the multi-mode X-band pulsed Doppler radar system test model for helicopter-borne flight test. This radar system consists of 4 LRUs(Line-Replacement Unit), which include antenna unit, transmitter and receiver unit, radar signal & data processing unit and display Unit. The developed core technologies include the planar array antenna, TWTA transmitter, coherent I/Q detector, digital pulse compression, MTI, DSP based Doppler FFT filter, adaptive CFAR, moving clutter compensation, platform motion stabilizer, and tracking capability. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test as well as helicopter-borne field tests including MTD(Moving Target Detector) capability for the Doppler compensation due to the moving platform motion.