• The Transactions of the Korea Information Processing Society
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• v.7 no.2
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• pp.365-372
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• 2000

he paper introduces evolutionary computing to Fractal Image Compression(FIC). In Fractal Image Compression(FIC) a partitioning of the image into ranges is required. As a solution to this problem there is a propose that evolution computation should be applied in image partitionings. Here ranges are connected sets of small square image blocks. Populations consist of $N_p$ configurations, each of which is a partitioning with a fractal code. In the evolution each configuration produces $\sigma$ children who inherit their parent partitionings except for two random neighboring ranges which are merged. From the offspring the best ones are selected for the next generation population based on a fitness criterion Collage Theorem. As the optimum image includes duplication in image data, it gets smaller in saving space more efficient in speed and more capable in image quality than any other technique in which other coding is used. Fractal Image Compression(FIC) using evolution computation in multimedia image processing applies to such fields as recovery of image and animation which needs a high-quality image and a high image-compression ratio.

• Tunnel and Underground Space
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• v.26 no.6
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• pp.475-483
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• 2016

A numerical analysis model capable of predicting the shape, the size and the potentiality of collapse of tetrahedral blocks considering the persistence obtained from the field survey of joint distribution around the underground excavation surface has been developed. Numerical functions of analyzing both the exposed trace distribution on the excavation surface and the formation of tetrahedral block controlled by the extent of joint surface have been established and linked to the previously developed three dimensional deterministic block analysis model. To illustrate the reliability of advanced numerical model the case of underground excavation in which the collapse of rock block had practically taken place was studied. Representative orientations of joint sets was determined based on the joint distribution pattern observed on the excavation surfaces. The formation of block on the roof of underground opening was analyzed to unveil the potential tetrahedral block the shape of which was very similar to the collapsed rock block. Mechanisms of collapse process has been also analyzed by considering the three dimensional shape of tetrahedral block.

• Journal of the Korean association of regional geographers
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• v.21 no.4
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• pp.716-727
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• 2015

The location and distribution of daycare centers do not reflect local daycare demand enough although government has increased facilities and financial supports to solve the low birthrate as a social problem. This study tried to examine spatial inequality of daycare center distribution by comparing the number of daycare facilities between city and rural communities in Jeollanam-Do. Analyzing the differences between city (5 Cities) and rural area (17 Guns) in Jeollanam-Do, it has been found that there were large differences in the number of available facilities per 1,000 children between Cities (10.9 facilities) and Guns as rural area (6.2 facilities). The average number of facilities in each City and Gun also showed a large discrepancy as a City has 147.8 facilities and a Gun has 15.4 facilities, respectively. There were total 78 Dong or Myeon with no facility at all as a dead zone of daycare, and 8 of them were Myeons in cities with 560 children, which accounted for 0.7% of total population of children in cities. On the other hand, 70 Myeons in Guns with 5,269 children have no facilities at all, which accounted for 11% of total population of children in Guns. Public facilities that parents prefer were more in cities (87) than Guns (28). Therefore, it is necessary to consider various childcare policies with minimizing discrepancies between city and rural area and investigating more accurate local demands and characteristics.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.367-375
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• 2006

This study investigated the effects of varying visuals in drawing and writing as methods to assist students in connecting and integrating multiple external representations provided in learning the particulate nature of matter. Seventh graders (N=233) at a coed middle school were assigned to control, static drawing (SO), dynamic drawing (DD), static writing (SW), and dynamic writing (DW) groups. The students were taught about "Boyle's Law" and "Charles's Law" for two class periods. Two-way ANCOVA results revealed that the scores of a conception test for the two drawing (SD, DD) groups and the two writing (SW, DW) groups were significantly higher than those for the control group. Within the writing groups, students of lower spatial visualization ability in the DW group scored significantly higher than those in the SW group. However, no significant differences were found in the scores of the conception test for the two drawing (SD, DD) groups regardless of students' visualization ability. Researchers also found that most students in both DD and DW groups had respectively positive perceptions of dynamic visuals in drawing or writing.

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.1-7
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• 2012

Purpose: The purpose of this study was to identify the effectiveness of multimodal pain control method in an early phase after arthroscopic rotator cuff repair, under interscalene brachial plexus block, this study was performed. Materials and Methods: The study was progressed with the 80 cases of arthroscopic rotator cuff repair. Interscalene brachial plexus block was used to all of the 80 cases and patients were divided into 2 groups. Group A consisted of patients injected with bupivacaine, through subacromial space catheter after surgery, and group B consisted of patients with additional method of multimodal pain control using oral opioids, acetaminophen-tramadol complex and selective COX2 inhibitor. Subacromial cathter was removed after injection in both groups. The pain during the day time and night time was compared on the operation day, postoperative 1st, 2nd, 3rd day and 2nd weeks, and it was measured with VAS (visual analogue scale) score. Additionally, the number of ketolorac injection and side-effect related to analgesics was compared between the 2 groups. Results : The mean VAS score of night time on the operation day and day/night time pain of the 1st, 2nd, 3rd day and 2nd weeks was 7.4, 7.0/6.8, 4.5/5.2, 4.8/5.0, 2.2/2.7 on group A and 6.5, 4.3/5.4, 3.2/4.3, 3.0/4.1, 2.4/2.5 on group B, respectively. Significant difference was observed in the night pain on the operation day, 1st, 2nd, 3rd day time and 1st night time pain (p<.05). The average number of ketololac injection was 1.1 and 0.5 in each group, and there was no difference in the frequency of side effects. Conclusion: Multimodal pain control method, after arthroscopic rotator cuff repair, showed an effective early pain control and improved patients' satisfaction.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.74-84
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• 2004

Purpose: Since I-125 emits low energy (27-35 keV) radiation, thinner crystal and collimator could be employed and, hence, it is favorable to obtain high quality images. The purpose of this study was to derive the optimized parameters of I-125 SPECT using a new simulation tool, GATE (Geant4 Application for Tomographic Emission). Materials and Methods: To validate the simulation method, gamma camera developed by Weisenberger et al. was modeled. Nal(T1) plate crystal was used and its thickness was determined by calculating detection efficiency. Spatial resolution and sensitivity curves were estimated by changing variable parameters for parallel-hole and pinhole collimator. Peformances of I-125 SPECT equipped with the optimal collimator were also estimated. Results: in the validation study, simulations were found to agree well with experimental measurements in spatial resolution (4%) and sensitivity (3%). In order to acquire 98% gamma ray detection efficiency, Nal(T1) thickness was determined to be 1 mm. Hole diameter (mm), length (mm) and shape were chosen to be 0.2:5:square and 0.5:10:hexagonal for high resolution (HR) and general purpose (GP) parallel-hole collimator, respectively. Hole diameter, channel height and acceptance angle of pinhole (PH) collimator were determined to be 0.25 mm, 0.1 mm and 90 degree. The spatial resolutions of reconstructed image of the I-125 SPECT employing HR:GP:PH were 1.2:1.7:0.8 mm. The sensitivities of HR:GP:PH were 39.7:71.9:5.5 cps/MBq. Conclusion: The optimal crystal and collimator parameters for I-125 Imaging were derived by simulation using GATE. The results indicate that excellent resolution and sensitivity imaging is feasible using I-125 SPECT.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.168-172
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• 2014

A new sustain driving method is proposed to improve luminous efficiency by the generation of the self-erasing discharge during a sustain period in AC plasma display panel. As one subfield time in the conventional AC PDP is divided into the reset, address, and sustain period. Among them, as the square sustain waveform is alternately applied to the X and Y electrodes on the front plate during the sustain period, the plasma discharge for displaying the image is continuously produced. Meanwhile, in the conventional driving method, the address waveform applied to the A electrode on the rear plate is only driving during an address period and grounded during a sustain period. In this experiment, the negative pulse is applied to the A electrode at the latter part of the sustain pulse for improving the luminous efficiency producing the self-erasing discharge during the sustain period. The negative pulse on the A electrode can change from the space to the wall charge and induce the additional discharge by the accumulated wall charge when the voltages of three electrodes are grounded. As a result, the luminous efficiency will be measured with changes in the voltage level of the A electrode and the new driving method can be improved to the luminous efficiency about 32 % compared with the conventional driving method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8C
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• pp.721-730
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• 2012

In this paper the problem of a moving control of an automatic guided vehicle(AGV) which transports a dead body to a designated cinerator safely in a crematorium, an special indoor environment, will be discussed. Since a method of burying guided lines in the floor is not proper to such an environment, a method of moving control of an AGV based on infrared ray sensors is now proposed. With this approach, the AGV emits infrared ray to the landmarks adheres to the ceiling to find a moving direction and then moves that direction by recognizing them. One of the typical problems for this method is that dead zone and/or overlapping zone may exist when the landmarks are deployed. To resolve this problem, an algorithm of recognizing double landmarks at each time is applied to minimize occurrences of sensing error. In addition, at the turning area to entering the designated cinerator, to fit an AGV with the entrance of the designated cinerator, an algorithm of controlling the velocity of both the inner and outer wheel of it. The functional correctness of our proposed algorithm has been verified by using a prototype vehicle. Our real AGV system has been applied to a crematorium and it moves automatically within an allowable range of location error.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.50-57
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• 2017

In this study, the experiment for determining shock loss at the branch is conducted for the design of network double-deck road tunnel ventilation. The shock loss coefficient that determines the quantity of shock loss has been considered only regarding the constant aspect ratio of circular or rectangular section. However the suggestion of shock loss coefficient is needed since the aspect ratio of double-deck road tunnel for small vehicle is considered around 1:3 with the low height in Korea. The experiment model was made with the scale of around 1:23 applying Reynolds similarity law, so that the shock loss coefficient on the branch of the large aspect ratio was measured. The result of the study showed that shock loss coefficients of both split branch and straight branch were measured two to three times higher than those calculated from the theoretical equation or design values of previous studies. Therefore the study resulted the effect of large aspect ratio on shock loss coefficient was huge, and it is expected that precise design value can be suggested for the design of network double-deck tunnel ventilation.

• Korean Security Journal
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• no.39
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• pp.387-411
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• 2014

School violence is now considered not only as a problem for a victim and a offender themselves, but also as a social problem that requires responsibilities of school, home, society, and even nation. Crimes and risk factors are various inside and outside of school. In terms of solving those problems, this study examines the actual condition of school violence among students. In addition, it is considered what efforts are conducted by police to establish a safe school environment and the problems that derive from it. Futhermore, this study aims to discuss the ways of using the private security with regard to dealing with school violence. In this society, the expectation of security service from the police is increased as time passed. However, police has limited resources, thus it is beyond their practice. Policing has changed from being monopolized by government to cooperating with various security agents. Community is not considered as the subject for enforcing the law anymore, but as the cooperator for effective policing. With regard to the limitation of police force, using the private security is an effective alternative. Therefore, it is required that private security should be assigned legal authority and shared information with schools in order to patrol the blind spot. Finally, school violence prevention efforts should be conducted by applying physical and electronic security.