• Safety and Health at Work
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• v.14 no.2
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• pp.229-236
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• 2023

Background: In workers with moderate to severe work-related traumatic brain injury (wrTBI), this study aimed to investigate the effect of the timing of rehabilitation therapy initiation on the length of hospital stay and the factors that can influence this timing. Methods: We used data obtained from the Republic of Korea's nationwide Workers' Compensation Insurance. In the Republic of Korea, between the years 2010 and 2019, a total of 26,324 workers filed a claim for compensation for moderate to severe wrTBI. Multiple regression modeling was performed to compare the length of hospital stay according to the timing of rehabilitation therapy initiation following wrTBI. According to the timing of the initiation of rehabilitation therapy following TBI, the proportions of healthcare institutions that provided medical care during each admission step were compared. Results: The length of hospital stay for workers who started rehabilitation therapy within 90 days was significantly shorter than that for workers who started rehabilitationment were first admitted to tertiary hospitals. Approximately 39% of patients who received delayed rehabilitation treatment were first admitted to general hospitals, and 28.5% were first admitted to primary hospitals. Conclusions: Our findings demonstrate the importance of early rehabilitation initiation and that the type of healthcare institution that the patient is first admitted to after wrTBI may influence the timing of rehabilitation initiation. The results of this study also emphasize the need to establish a Worker's Compensation Insuranceespecialized rehabilitation healthcare delivery system.

• Korean Journal of Culture and Social Issue
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• v.16 no.2
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• pp.103-124
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• 2010

The purpose of the present study was to examine the relationships among private tutoring hours, academic motivation, use of learning strategies, and academic achievement test scores using structural equation modeling. The sample consisted of 3,607 7th graders from Korean middle schools who were included in the Korean Education Longitudinal Study. The results suggest that there was no evidence that the private tutoring hours predicted students' motivation and learning strategy use. It was found that the private tutoring hours predicted achievements in English and Math, but it was negligible in magnitude. As for achievement test scores, academic motivation and the use of learning strategies played more critical role rather than the private tutoring hours.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.46-54
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• 2006

Recently, the important of a personal identification is increasing according to expansion using each on-line commercial transaction and personal ID-card. Although a personal ID-card embedded RFID(Radio Frequency Identification) tag is gradually increased, the way for a person's identification is deficiency. So we need automatic methods. Because RFID tag is vary small storage capacity of memory, it needs effective feature extraction method to store personal biometrics information. We need new recognition method to compare each feature. In this paper, we studied the face verification system using Hippocampal neuron modeling algorithm which can remodel the hippocampal neuron as a principle of a man's brain in engineering, then it can learn the feature vector of the face images very fast. and construct the optimized feature each image. The system is composed of two parts mainly. One is feature extraction using NMF(Non-negative Matrix Factorization) and LDA(Linear Discriminants Analysis) mixture algorithm and the other is hippocampal neuron modeling and recognition simulation experiments confirm the each recognition rate, that are face changes, pose changes and low-level quality image. The results of experiments, we can compare a feature extraction and learning method proposed in this paper of any other methods, and we can confirm that the proposed method is superior to the existing method.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.655-664
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• 2018

Retina transforms the external light into electrical signal that stimulates visual cortex of the brain. Electrical modeling of the retina is useful to understand its structure and action that is a prerequisite to implement the retina as a hardware device. This paper introduces a 2-D electrical network model of vertebrate's retina considering signal pathway of retinal cells and synapses. We implemented a simulator of the retina based on the electrical network model to analyze its operation under various circumstances. Compared to the prior studies, It might contribute designing of artificial retina device in terms of that this study specifically observed input and output reactions of each cell and synapse node under various light intensity on the retina.

• BMB Reports
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• v.56 no.1
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• pp.15-23
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• 2023

After birth, animals are colonized by a diverse community of microorganisms. The digestive tract is known to contain the largest number of microbiome in the body. With emergence of the gut-brain axis, the importance of gut microbiome and its metabolites in host health has been extensively studied in recent years. The establishment of organoid culture systems has contributed to studying intestinal pathophysiology by replacing current limited models. Owing to their architectural and functional complexity similar to a real organ, co-culture of intestinal organoids with gut microbiome can provide mechanistic insights into the detrimental role of pathobiont and the homeostatic function of commensal symbiont. Here organoid-based bacterial co-culture techniques for modeling host-microbe interactions are reviewed. This review also summarizes representative studies that explore impact of enteric microorganisms on intestinal organoids to provide a better understanding of host-microbe interaction in the context of homeostasis and disease.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.17-24
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• 2011

Purpose: Presently in the nuclear medicine field, the high-speed image reconstruction algorithm like the OSEM algorithm is widely used as the alternative of the filtered back projection method due to the rapid development and application of the digital computer. There is no to relate and if it applies the optimal parameter be clearly determined. In this research, the quality change of the Jaszczak phantom experiment and brain SPECT patient data according to the iteration times and subset number change try to be been put through and analyzed in 3D OSEM reconstruction method of applying 3D beam modeling. Materials and Methods: Patient data from August, 2010 studied and analyzed against 5 patients implementing the brain SPECT until september, 2010 in the nuclear medicine department of ASAN medical center. The phantom image used the mixed Jaszczak phantom equally and obtained the water and 99mTc (500 MBq) in the dual head gamma camera Symbia T2 of Siemens. When reconstructing each image altogether with patient data and phantom data, we changed iteration number as 1, 4, 8, 12, 24 and 30 times and subset number as 2, 4, 8, 16 and 32 times. We reconstructed in reconstructed each image, the variation coefficient for guessing about noise of images and image contrast, FWHM were produced and compared. Results: In patients and phantom experiment data, a contrast and spatial resolution of an image showed the tendency to increase linearly altogether according to the increment of the iteration times and subset number but the variation coefficient did not show the tendency to be improved according to the increase of two parameters. In the comparison according to the scan time, the image contrast and FWHM showed altogether the result of being linearly improved according to the iteration times and subset number increase in projection per 10, 20 and 30 second image but the variation coefficient did not show the tendency to be improved. Conclusion: The linear relationship of the image contrast improved in 3D OSEM reconstruction method image of applying 3D beam modeling through this experiment like the existing 1D and 2D OSEM reconfiguration method according to the iteration times and subset number increase could be confirmed. However, this is simple phantom experiment and the result of obtaining by the some patients limited range and the various variables can be existed. So for generalizing this based on this results of this experiment, there is the excessiveness and the evaluation about 3D OSEM reconfiguration method should be additionally made through experiments after this.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.867-870
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• 2014

Purpose: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) ependymoma data to identify predictive models and potential disparity in outcome. Materials and Methods: This study analyzed socio-economic, staging and treatment factors available in the SEER database for ependymoma. For the risk modeling, each factor was fitted by a Generalized Linear Model to predict the outcome ('brain and other nervous systems' specific death in yes/no). The area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate the modeling errors. Risk of ependymoma death was computed for the predictors for comparison. Results: A total of 3,500 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 79.8 (82.3) months. Some 46% of the patients were female. The mean (S.D.) age was 34.4 (22.8) years. Age was the most predictive factor of outcome. Unknown grade demonstrated a 15% risk of cause specific death compared to 9% for grades I and II, and 36% for grades III and IV. A 5-tiered grade model (with a ROC area 0.48) was optimized to a 3-tiered model (with ROC area of 0.53). This ROC area tied for the second with that for surgery. African-American patients had 21.5% risk of death compared with 16.6% for the others. Some 72.7% of patient who did not get RT had cerebellar or spinal ependymoma. Patients undergoing surgery had 16.3% risk of death, as compared to 23.7% among those who did not have surgery. Conclusion: Grading ependymoma may dramatically improve modeling of data. RT is under used for cerebellum and spinal cord ependymoma and it may be a potential way to improve outcome.

• Journal of Korean Neurosurgical Society
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• v.47 no.2
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• pp.128-133
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• 2010

Objective : The secondary verification of Leksell Gamma Knife treatment planning system (LGP) (which is the primary verification system) is extremely important in order to minimize the risk of treatment errors. Although prior methods have been developed to verify maximum dose and treatment time, none have studied maximum dose coordinates and treatment volume. Methods : We simulated the skull shape as an ellipsoid with its center at the junction between the mammillary bodies and the brain stem. The radiation depths of the beamlets emitted from 201 collimators were calculated based on the relationship between this ellipsoid and a single beamlet expressed as a straight line. A computer program was coded to execute the algorithm. A database system was adopted to log the doses for $31{\times}31{\times}31$ or 29,791 matrix points allowing for future queries to be made of the matrix of interest. Results : When we compared the parameters in seven patients, all parameters showed good correlation. The number of matrix points with a dose higher than 30% of the maximal dose was within ${\pm}\;2%$ of LGP. The 50% dose volume, which is generally the target volume, differs maximally by 4.2%. The difference of the maximal dose ranges from 0.7% to 7%. Conclusion : Based on the results, the variable ellipsoid modeling technique or variable ellipsoid modeling technique (VEMT) can be a useful and independent tool to verify the important parameters of LGP and make up for LGP.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.417-424
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• 2009

Osteoclasts, derived from multipotent myeloid progenitor cells, play homeostatic roles in skeletal modeling and remodeling, but may also destroy bone in pathological conditions such as osteoporosis and rheumatoid arthritis. Osteoclast development depends critically on a differentiation factor, the receptor activator of NF-${\kappa}B$ ligand (RANKL). In this study, we found that the hexane soluble fraction of the common fig Ficus carica (HF6-FC) is a potent inhibitor of osteoclastogenesis in RANKL-stimulated RAW264.7 cells and in bone marrow-derived macrophages (BMMs). HF6-FC exerts its inhibitory effects by suppression of p38 and NF-${\kappa}B$ but activation of ERK. In addition, HF6-FC significantly decreased the expression of NFATc1 and c-Fos, the master regulator of osteoclast differentiation. The data indicate that components of HF6-FC may have therapeutic effects on bone-destructive processes such as osteoporosis, rheumatoid arthritis, and periodontal bone resorption.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.421-423
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• 2007

The paper used to the Neral Netwok for a forecasting conservation system A neural network is a powerful data modeling tool that is able to capture and represent complex input/output relationships. The motivation for the development of neural network technology stemmed from the desire to develop an artificial system that could perform "intelligent" tasks similar to those performed by the human brain. The true power and advantage of neural network lies in their ability to represent both linear and non-linear relationships and in their ability to learn these relationships directly from the data being modeled. Form results of this study, the Neral Netwok is will play an important role for insulation diagnosis system of real site GIS and power equipment using $SF_6$ gas.