• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.599-607
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• 2000

In this study, experiments have been performed to examine the effects of background gray-level on the depth-of-field and on the in-focus criteria. The normalized value of contrast(VC) and the gradient indicator(GI) were used as the in-focus criteria for the small and the large size-ranges of particles, respectively. The slightly larger number of pixels were detected with the brighter background. The maximum of the normalized value of contrast(VCmax) is decreased with the brighter background and its deviation from that with the background gray-level of 160 turned out to be about $pm$15% when the background gray-level changes from 100 to 200. However, the maximum gradient indicator(GImax) changes with the background gray-level within only $pm$5%. The depth-of-field for the VC-applicable particle-size range is largely dependent on the background gray-level. On the other hand, the depth-of-field for the GI-applicable particle-size range changes only slightly with the background gray-level. To keep the normalized standard deviation of the particle size within 0.1, the background gray-level should be set 160$pm$20 for both the VC-applicable and GI-applicable ranges which cover the particle size between $10{\mu}m$ and $300{\mu}m$.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.4
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• pp.315-321
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• 2009

In this paper, a level set based energy functional is proposed, the minimization of which results in simultaneous reference background image modeling and foreground segmentation. Due to the mutual constraint of the two processes, a good estimate of the background can be obtained with a small number of frames, and due to the use of the level set, an Euler-Lagrange equation that directly solves the problem can be derived.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.97-103
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• 2015

The people who are in the noise factory are difficult to hear and recognize about fire and to evacuate quickly when a fire occurs. This study was conducted to analyze workplace's background noise of 31 factories in Incheon and to know the workplace noise level comparing to fire alarm sound level. The measured average noise level was 96.8dB(A). Noise level of measured result was exceeded as 6.8dB(A) comparing to NFSC (National Fire Safety Code) noise level of 90dB. NFPA suggests that when background noise exceeds 85dB or more than that, other methods should be considered to know alarm sound. Also fire alarm sound should exceed more than 15dB(A) comparing to background noise level. Therefore it was concluded that the design of the fire alarm systems should not be applied to the workplace without considering background noise and it needs to be improved with regulations and the systems.

• Journal of The Korean Association For Science Education
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• v.30 no.7
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• pp.908-919
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• 2010

The objectives of this study were to investigate what kind of background concepts is necessary to help that high school students easily understand meiosis and to find out how these background concepts affect students' understanding of meiosis. To achieve these objectives, first this study surveyed meiosis background concepts that high school teachers think. Based on 8 background concepts - nuclear phases, chromosome, mitosis, reproduction, gamete, gene, mother/daughter cell - of previous survey, the questionnaire was made for the 10th(724) and 11th(862) grade students and then was analyzed for the effect of meiosis background concepts on the high school students' understanding of meiosis. Results of the analysis revealed that the influential background concepts are as follow; cell cycle, chromosome in the advanced level, mother/daughter cell, mitosis, chromosome, nuclear phases in the intermediate level, mother/daughter cell, nuclear phases, gene in the low level. And the achievement according to item types was differed not by meiosis achievement, but by each background concepts.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.487-493
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• 1999

To predict the background level of harmonics produced by household appliances, information on the site, capacity, and usage pattern of these loads arenecessary. However, as household appliances are distributed widely and various in type, it is difficult to know these kinds of information accurately. This paper presents a method for estimation of background level of harmonics produced by distributed harmonic sources with readily available data. Large industrial customers are excluded from this study. In this paper, customers are grouped into three classes, i.e. residential, commercial, and industrial. Typical customers for each class are assumed and characteristics of their equipments are modeled. As the proposed method does not require harmonic measurement, it can be employed to forecast voltage total harmonic distribution (VTHD) in the future. An illustrative example is described.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.1
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• pp.38-47
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• 1989

Calculated results for subband structures of electrons in GaInAs/InP hegerojunctions are presented, and their sensitivity to two parameters background impurity concentrations in the GaInAs, heterojunction barrier height-is examined. Energy levels, Fermi level and population of the ground energy level are increased with background impurity concentrations. The difference of the ground and first-excited energy levels is also increased with the increase of barrier height. However, the difference of the energy levels is almost invariable with barier height. But, population of the ground energy level decreases, but that of the first-excited energy level shows a slight increase.

• Phonetics and Speech Sciences
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• v.3 no.3
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• pp.173-179
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• 2011

The present study was performed to investigate the intelligibility of voice disorder patients by providing the various background noise levels. Four sets of 12-sentence-stimuli produced by 11 voice disorder patients were prepared, and 5 minute-news from radio broadcasting studio were used as a background noise. 30 listeners assigned intelligibility score of each sentence with visual analog scale. Each set of sentences was provided with 20dB, 10dB, 0dB noise (same intensity with stimuli), and, finally, with no noise. As results, as background noise level increased, intelligibility scores were lowered with statistical significance. Even though in the same severity, more loud background noise showed much lower scores than less loud noise. When 10dB noise was provided, intelligibility scores showed the biggest difference among the degree of severity.

• Journal of the Korean Home Economics Association
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• v.38 no.2
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• pp.109-122
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• 2000

The purpose of this study is to find a mother's influence on her children regarding environmental preservation. The questions of this study are how a mother's background variables influence on their own behaviors, how the children's background variables influences on their own behaviors, how a mother's background variables influence on their children behaviors. This is used self-writing questionaires the 538 subjects are 4th, 5th and 6th grade children and their mothers living in Kwangiu, in June, 1998. The data are analyzed by Frequency, Percentage, Mean, Pearson's correlation, Regression analysis, Path analysis, Coronbach'$\alpha$ coefficent, and Factor analysis. These are the major resets of this study. 1) In case of mothers, the background variables for them to be influenced the environmental presentation behaviors show the frequency of contact for environmental information, average income, family cohesions, the level of communication, egoistic orientation, and age. 2) In Children, the background variables which are influenced on their environmental presentation behaviors represent the frequency of contact for environmental information, family cohesion, biospheric orientation, and the grade level of children. This is, the children who have the more chance of environmental information contact, the higher family cohesion, the higher biospheric orientation, and the lower grade level show the more environmental preservation behaviors. 3) The children who grow seeing their mothers'environmental behaviors such as sorted disposal, recycle behavior, and purchasing behaviors also show the more same behaviors.

• Nuclear Engineering and Technology
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• v.25 no.3
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• pp.361-370
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• 1993

Low power physics tests should be peformed for the domestic pressurized light water reactors (PWRs) after refueling. The tests are peformed to ensure that operating characteristics of the core are consistent with predictions and that the core can be operated as designed. But in some low power physics tests, slow but steady reactivity increasing phenomena were noticed after step reactivity insertion by the control rod movement. These reactivity increasing phenomena are due to the low flux level and the gamma background because an uncompensated ion chamber (UIC) is used as the ex-core neutron detector. The gamma background may affect the results or the lour power physics tests. The aims or this paper are to analyze the grounds of such phenomena, to simulate a reference bank worth measurement test and to present a resolution quantitatively. In this study, the gamma background level was estimated by numerically solving the point kinetics equations accounting the gamma background effect. The reactivity computer check test was simulated to verify the model. Also, an appropriate neutron flux level was determined by simulating the reference bank worth measurement test. The determined neutron flux level is approximately 0.3 of the nuclear heating flux. This level is about 3 times as high as the current test upper limit specified in the test procedure. Then, the findings from this work were successfully applied to Kori unit 4 cycle 7 and Yonggwang unit 1 cycle 7 physics tests.

• The KIPS Transactions:PartB
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• v.14B no.3 s.113
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• pp.171-182
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• 2007

We propose a simple method for tracking a nonparameterized subject contour in a single video stream with a moving camera and changing background. Then we present a method to eliminate the tracked contour object by replacing with the background scene we get from other frame. First we track the object using LOD (Level-of-Detail) canny edge maps, then we generate background of each image frame and replace the tracked object in a scene by a background image from other frame that is not occluded by the tracked object. Our tracking method is based on level-of-detail (LOD) modified Canny edge maps and graph-based routing operations on the LOD maps. We get more edge pixels along LOD hierarchy. Our accurate tracking is based on reducing effects from irrelevant edges by selecting the stronger edge pixels, thereby relying on the current frame edge pixel as much as possible. The first frame background scene is determined by camera motion, camera movement between two image frames, and other background scenes are computed from the previous background scenes. The computed background scenes are used to eliminate the tracked object from the scene. In order to remove the tracked object, we generate approximated background for the first frame. Background images for subsequent frames are based on the first frame background or previous frame images. This approach is based on computing camera motion. Our experimental results show that our method works nice for moderate camera movement with small object shape changes.