• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1764-1773
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• 2018

A-PET is a quad-head PET scanner developed for use in small-animal imaging. The dimensions of its volumetric field of view (FOV) are $46.1{\times}46.1{\times}46.1mm^3$ and the gap between the detector modules has been minimized in order to provide a highly sensitive system. However, such a small FOV together with the quad-head geometry causes image quality degradation. The main factor related to image degradation for the quad-head PET is the mispositioning of events caused by the penetration effect in the detector. In this paper, we propose a precise method for modelling the system at the high spatial resolution of the A-PET using a LOR (line of response) based ML-EM (maximum likelihood expectation maximization) that allows for penetration effects. The proposed system model provides the detection probability of every possible ray-path via crystal sampling methods. For the ray-path sampling, the sub-LORs are defined by connecting the sampling points of the crystal pair. We incorporate the detection probability of each sub-LOR into the model by calculating the penetration effect. For comparison, we used a standard LOR-based model and a Monte Carlo-based modeling approach, and evaluated the reconstructed images using both the National Electrical Manufacturers Association NU 4-2008 standards and the Geant4 Application for Tomographic Emission simulation toolkit (GATE). An average full width at half maximum (FWHM) at different locations of 1.77 mm and 1.79 mm are obtained using the proposed system model and standard LOR system model, which does not include penetration effects, respectively. The standard deviation of the uniform region in the NEMA image quality phantom is 2.14% for the proposed method and 14.3% for the LOR system model, indicating that the proposed model out-performs the standard LOR-based model.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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• pp.235-245
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• 2015

Objective: The purpose of this study is to develop visual complexity metrics based on theoretical bases. Background: With the development of IT technologies, drivers process a large amount of information caused by automotive human-machine interface (HMI), such as a cluster, a head-up display, and a center-fascia. In other words, these systems are becoming more complex and dynamic than traditional driving systems. Especially, these changes can lead to the increase of visual demands. Thus, a concept and tool is required to evaluate the complicated systems. Method: We reviewed prior studies in order to analyze the visual complexity. Based on complexity studies and human perceptual characteristics, the dimensions characterizing the visual complexity were determined and defined. Results: Based on a framework and complexity dimensions, a set of metrics for quantifying the visual complexity was developed. Conclusion: We suggest metrics in terms of perceived visual complexity that can evaluate the in-vehicle displays. Application: This study can provide the theoretical bases in order to evaluate complicated systems. In addition, it can quantitatively measure the visual complexity of In-vehicle information system and be helpful to design in terms of preventing risks, such as human error and distraction.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.2
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• pp.131-141
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• 2020

This study examines the poverty indicators in Northeast region of Thailand by adopting the global Multidimensional Poverty Index (MPI) methodology and the national survey of Minimum Basic Needs (MBN) of Thailand. Data are collected from three different districts in Khon Kaen province namely: Khok Po Chai, Sam Sung, and Nam Pong. The sample size is 187 households. Data analysis uses Ordinary Least Square (OLS) regression approach and includes 7 dimensions of poverty (health, environment, education, economy, Thai value, asset? empowerment, and digital literacy) with a total of 41 indicators. This study has found that poverty indicators in Khon Kaen province remains centered around the aspects of health and employment dimensions. While a change of family structure in the Thai society since 1960s reduces the family size, household saving substantially increases over the years. The effects of health dimension in poverty, on the other hand, appears on the other poverty dimension of Thai value, which include (1) a bad living habit of head of household (smoke or alcohol consumption) that links with illness and disease, (2) religious practice, and (3) chronic illness. Lastly, there are income gaps of different careers in the area, which suggests the issue of income inequality.

• Ocean and Polar Research
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• v.34 no.2
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• pp.165-173
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• 2012

A 26 day experiment was conducted to determine the effects of feeding and starvation on the survival, morphology, and histology in chum salmon (Oncorhynchus keta) fry. We included three experimental groups: starved, fed, and initial. The survival and growth rates were lower in the starved group than in the fed group (P < 0.05). In the starved group, survival began to decline after 16 days, and all fish had died after 26 days. We determined the effects of starvation on the morphometric parameters using the truss and classical dimensions. The dimensions in the head region were larger in the starved group than in the initial and fed groups. In contrast, the truss dimensions of the fed group were larger than those of the initial and starved groups. Starvation reduced the heights of the hepatocyte nuclei and of the intestinal epithelium (P < 0.05). The starved group also showed atrophy of the digestive structures and shrinkage of the foregut and midgut. Starvation led to the degeneration and atrophy of the exocrine pancreas, in which the lumen was markedly diminished and the folds of mucosa were less apparent. The hepatocyte morphology in the starved group was abnormal compared with that of the initial and fed groups, with highly compact, irregularly shrunken nuclei. Melanomacrophages were randomly distributed in the kidneys of the starved group, and their abundance increased rapidly during the experiment. In contrast, neither the initial nor fed group had any melanomacrophages. These results suggest that the nutritional parameters used in this study are useful indices of nutritional status in chum salmon.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.27-31
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• 1976

A study was performed to investigate the size of pharynegeal cavity and sexual differences between Korean adult male and female by introducing linear analysis of the lateral cephalogram. The radiograms were composed of 46 adult males aged 24.64 and 52 adult females aged 22.74 respectively. In order to study and measure the pharyngeal area the following skeletal landmarks were selected: S, N, A, Ptm, B, H, H', M, S' N, FH and CV, and the angle CV-FH was measured to provide a factor for correction of error resulting from improper head positioning of subjects, especially in the relative positions of A and H, while radiography. All points to be measured were projected at right angles to the Frankfort plane. For the purpose of measuring the anteroposterior dimensions of pharyngeal cavity the distances were measured in A-Ptm, A-S, S-Ptm and CV-H, and vertical measurements were made in SN-A, SN-PNS, SN-H' and M-H'. The obtained results were as follows: 1. The pharyngeal cavity is broader in the vertical than in the anteroposterior diameter in both sex and the maxium sexual differences were showed in the distances between SN and H', and minimal sexual differences in the distances between S and Ptm. 2. In general, the measurements of male were larger than those of female in the anteroposterior dimensions of pharyngeal cavity, but the distances bet-ween A and S, between CV and H showed significant sexual differences when evaluated statistically. 3. All of the measurements were larger in male than in female in vertical dimensions of pharyngeal cavity, and there were statistical significances of sexual differences in all variables.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.63-70
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• 1990

The aim of this study has been to investigate the growth of the pharynx and sexual differences in the lateral cephalograms of Korean children. The material includes 173 cepalograms from two groups composed of 51 males aged 12.0 years and 39 females aged 12.2 years in group 2, and 45 males aged 7.4 years and 39 females aged 7.5 year in group 1, respectively. In order to study and measure the pharyngeal area the following skeletal landmarks were selected: S, N, A, Ptm, B, H, H', M, S-N, FH and CV, and the angle CV-FH was measured to provide a factor for correction of error resulting from improper head positioning of subjects, especially in relative positions of A and H, while radiography. For each variable the statistically treated data have been presented in the table Ⅱ, Ⅲ, Ⅳ. The main results are presented as follows: 1. In general, the measurements of male were larger than those of female in antero-posterior dimension of pharyngeal cavity, but all variables did not show significant sexual differences in both groups when evaluated statistically. 2. All of the measurements were larger in male than in female in vertical dimensions of pharyngeal cavity in group 2, and there were statistical significances of sexual differences in the variables except M-H', but all variables did not show significant sexual differences in group 1 when evaluated statistically. 3. The dimensional increase of the pharynx by the growth in the vertical dimensions was shown to be greater than in the antero-posterior dimensions in the both sexes.

• Journal of Korean Academy of Nursing Administration
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• v.3 no.1
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• pp.37-50
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• 1997

The purpose of this study was to identify the gap between need-level and demonstration-level in nursing managerial competencies. In addition, the study proposes solutions to narrow this gap. The results of this study are as follows : 1) The mean score for need-level of each item was 4.0, and for demonstration-level, 3.5. This indicates that military hospital head nurses demonstrate a higher level of managerial competencies than the moderate level on all items. But items which were related to resource/ cost/ information managament, staff development management and professionalism management got relatively low ratings in the need-level. 2) The mean score for need-level of each category was 4.14, and for demonstration-level, 3.53. Categories on the individual dimension got a higher rating than categories on the group or organization dimension in both need-level and demonstration level. 3) The gap between need-level and demonstration-level appeared in all items(p<.05) and categories(p<.001). Although the gap was relatively low, it indicates that it is essential to plan a developmemt program for all nursing management competencies for military hospital head nurses. 4) There were significant differences in the gap between need-level and demonstration-level according to specific characteristics of the subjects. The gap did not appear in many categories on the individual dimension where the number of nursing staff was more than 10, a major grade, ICU head nurse or for head nurses having a long career. 5) Need-level and demonstration-level showed a difference according to specific characteristics of the subjects, because need-level and demonstration-level were higher where the number of nursing staff was more than 10, a major grade, and for ICU or Medical ward head nurses. The categories which showed need-level difference and demonstration-level differences according to specific characteristics of the subjects existed almostly completely in the group and organization dimension. Gap-level differences according to the number of hospital bed existed in only two categories. 6) The general causes of the gap were indicated to be 'Knowledge/ skill/ experience deficit', 'Limitation of rules and systems/ Inappropriate organizational environment' for most items, categories, and dimensions. The results of this study indicate that extensive competency developing strategies must be developed, because a gap was found in all items and categories. Specially, there is a need to concentrate attention on competencies in the group and organizational dimension which had a wider gap level. And it is important to take an individual approach according to the cause for each gap. In order to produce effective competency developing strategies, top managers must have sinsights into the importance of nursing staff development and nursing officer's efforts to develop themselves must be achieved. Further multi-dimensional(education, personnel-policy, nursing/ organizational environment) solutions to the gap must be developed and utilized.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.31-36
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• 2020

Purpose: The purpose of this study was to investigate the impact of radiotherapy on mandibular bone tissue in head and neck cancer patients through an analysis of pixel intensity and fractal dimension values on digital panoramic radiographs. Materials and Methods: Thirty patients with radiographic records from before and after 3-dimensional (3D) conformational radiotherapy were selected. A single examiner carried out digital analyses of pixel intensity values and fractal dimensions, with the areas of interest unilaterally located in the right angle medullary region of the mandible below the mandibular canal and posterior to the molar region. Results: Statistically significant decreases were observed in the mean pixel intensity (P=0.0368) and fractal dimension (P=0.0495) values after radiotherapy. Conclusion: The results suggest that 3D conformational radiotherapy for head and neck cancer negatively affected the trabecular microarchitecture and mandibular bone mass.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.95-102
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• 1997

So far, several fractal models of fluid flow in a fractured aquifer have been developed. In this study, a new fractal model is derived that considers transient flow in the dual-porosity aquifer with the fracture skin between the fissure and the block, and the storage capacity and the wellbore skin on the pumping well. Constant-head upper boundary is specified in the block. This model is a generalized one which comprises both modified Hantush equation (1960) and Boulton-Streltsova equation (1978). Type curves are plotted for different flow dimensions (0.5, 1, 1.5, 2, 2.5 and 3) with various values of the leakage factor and the fracture skin. They show dimensionless drawdown in the pumping well and observation wells located either in the fissure system or in the matrix block.

• Journal of the Korean Home Economics Association
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• v.30 no.4
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• pp.49-61
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• 1992

The purpose of this study is to set the standard items of the garment size for infants. The studied subject consisted of 560 infants from at brith to 12 months of Pusan and Gyeongnam area. The Results from this analysis are as follows; 1. The most significant growths in body dimensions of infants as an month age advanced. Expecially, stature, weight and the items of height and length showed a quite rapid growth, but the items of girth, breadth and depth showed a slow growth. 2. The coefficient of correlation between stature and weight shows high value. The result of interpretation of the extracted components are as follows. It will be more appropriate to use the method of parallerizing with height and weight items rather than with month age in classficating and indicating of size for infant garment and in taking the head girth as basic item of infant for head-gears. Consequently, as the standard items for the classification of clothing constuction of infants, it is advisable to select weight alone or both stature and weight. 3. According to the method of classifying the somatotype by the index of body soundness, the Rohrer.Kaup index on the basis of standard items, weight and stature was divided into somatotype.