• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.139-144
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• 2015

Recently, to realize sound-absorbing structures, we have to insert sound-absorbing materials into wall. These shapes are taken limitations because sound-absorbing materials should be fixed. Therefore, the sound absorption is changed by environment that used the sound-absorbing materials. On the other hand, we will take same effect without sound-absorbing material, if we change the shape of wall to sound absorbing structure. If we use this sound absorbing structure, we can get benefits by removing limitation of materials. Therefore we suggest perforated plate for effective sound-absorbing structure. We confirmed the function of sound-absorption of this structure using equivalent property. Then, we found the similarity between perforated plate and resonator. Also, we verify these theories through computer simulation by FEM(Finite Element Method). Finally, we validated that perforated plate has function of sound absorption without sound-absorbing material. This perforated plate is used for sound-absorbing material of buildings and transportations such as vehicle, train etc. Also, these results could be further used basic tool for design of sound-absorption structure.

• Management & Information Systems Review
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• v.17
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• pp.107-133
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• 2005

The purpose of this study was to analyze a trend of profitability classified by characteristics of hospitals and to analyze related factors. The data for this study were derived from survey material conducted by the Korean Hospital Association on 33 hospitals in Korea between 1993 and 2002. Profitability was measured in the aspect of investment profit rate and operation profit rate with net profit to total assets, normal profit to total assets and operating margin to gross revenue as dependent variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, region), financial factors (total asset turnover, liabilities to total assets, current ratio, fixed ratio, inventories turnover, personnel costs per operation profit, material costs per operation profits), composition of manpower and facilities(personnel and area per beds), productivity index(the number of daily patients per medical doctor, the number of daily patients per nurse), the score of quality assurance activities. First, Concerning the specialists per beds or area per beds and profitability of hospitals there was not statistically significant. Second, Those hospitals having the most daily patients per nurse had significantly higher profitability than the others, but the number of daily patients per medical doctor had little effect on the profitability. Thirds, Those hospitals having a higher proportion total asset turnover tended to show significantly higher profitability compared to other hospitals, but the liabilities to total assets and liquidity ratio had a little difference to the profitability. Those hospitals having a higher proportion personnel costs per operation profit and material costs per operation profits tended to show significantly lower hospital profitability compared to other hospitals. Fourth, In regression analysis, hospital profitability had negative relationship with personnel costs per operation profit or material costs per operation profits. While it had positive relationship with total asset turnover, the number of daily patients per nurse. In conclusion, private hospitals had higher profitability than that of public hospitals. Though factors related to profitability of hospital were different according to ownership, it is important for securing appropriate profitability by operating appropriate number of nurse, raising total asset turnover, and reducing personnel costs, material costs per operation profits. This study can be used as a baseline data for planning of hospital management. But the study may be limited in that the results cannot be generalized due to its small sample size. However, this longitudinal observation of 33 hospitals over ten year period has significant merit alone.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.451-457
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• 2020

In this study, the degree of motion sickness displayed according to actions in virtual reality is measured based on the SSQ tool, a measuring tool, and factors and symptoms affecting cyber motion sickness are investigated through comparative analysis. In the first experiment, the operation method experiment, the simple operation method is measured to be highly affected by the Nausea factor. As symptoms of this, nausea, burp and headache symptoms were developed. In the second experiment, the larger the body rotation radius, the higher the motion sickness was measured, and the greater the influence of Nausea factors. Symptoms of this were the symptoms of burping, headaches, and a full head. In the third experiment, the physical mobility experiment, motion sickness was measured highly in the non-action controller. It was measured to be greatly affected by the Nausea factor. Symptoms of this include fever, headache, and a full head. Through this study, we found that the more fixed and simple the body is operated in virtual reality, the more sensitive the user is to motion sickness, and the larger the radius of rotation, the more sensitive it is to motion sickness. This study is meaningful in identifying factors and symptoms that affect motion sickness and VR manipulation, and is expected to be used by developers in the future to recognize the degree and symptoms of motion sickness of users and to develop content.

• Journal of the Korea Society of Computer and Information
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• v.19 no.10
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• pp.221-230
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• 2014

In this study, we propose a learning method that can be extended to take advantage of the knowledge of the various disciplines in the project related to the subject to perform the process of restoring stork. The development program is grade 3.4 Group 4 class hours, grade 5.6 Group 4 class hours, total 8 class hours, and in each class hour, it was designed to be extended such creativity, problem solving skills, communication skills and ability to learn, based on knowledge and concepts of the elementary curriculum related to storks. Content validity was verified using a method consisting of 12 experts to verify the validity of the program. Feasibility evaluation of Lawshe (1975) content validity ratio for the analysis: we used (Content Validity Ratio CVR) calculation formula. As a result of a feasibility study in total 8 class hours, It was analyzed that match with the development effect except for program of grade 3.4 group 4 class hours. grade 3.4 group 4 class hours program was raised this issue for the academic linkage region, was fixed. Later, It is necessary to measure the degree of learning skills improves effectiveness by applying it to the elementary school students in the proposed research program.

• Journal of the Korean Society of School Health
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• v.6 no.2
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• pp.24-55
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• 1993

School health aims to guide and manage growing students from elementary schools to high schools in order to grow healthily through the formation of healthy life habits, the self-control health management guide and the making of pleasant school health environments. Even though this school health plays an important role in guiding the students who are in the period of growing to have a perfect personality as a democratic people of our country in the school education, there are many lacks, such as they still don't know the word itself, "school health" or recognize its importance. Also it's a real condition to practice items concerned with the health under the condition of unestablished structure. 1. The results of analyzing school health real conditions. Based on treatises concerned with school health and various statistical materials which are announced by concerned people. We divided and analyzed school health into the items concerned with health education, the items with health management, and the items with school health environments, and investigated the level of the present school health and its necessity. As the items concerned with health education, we investigated the necessary range of school health education, the effect of health education on children's daily life, family's health and the interesting contents of school health. And as the items with health management, I investigated children's obesity, dental caries, eyesight, clinics, a health examination, drug abuse, spirit health, providing meals for school children, and school health manpower. And as the items conerned with school health environments, we investigated the recognition of the problem of natural environments, the management of purification district around the school, the problem of environments within the school and classroom lighting. As the results of analyzing these, I realized that the present level of school health is still in unsatisfactory situation and school health is needed necessary. 2. The establishment of school health. In order to set the school health, above all, the management system of School health should be set. I classified and systemized the contents of each item which had been promoted till now according to the function. They are classified as followings Based on classifying school health into (1) health education, (2) health management and (3) health environments, I divided school health education into the health education of health subjects, the health education of concerned subjects and the education of health life. And I divided health management into the health managements for a prevention and a cure. And I divided health environments into the environment around the school and within the school. Each system set like these is not fixed invariably and I should keep the relationship of mutual supplement between health education and health management, between health management and health environments, and between health environments management and health education. When we run these systemetic school health, students' health could be maintained and improved to more proper directions.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.267-276
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• 2018

Objective : The beneficial effect of hypothermia after hemicraniectomy in malignant middle cerebral artery (MCA) infarction has been controversial. We aim to investigate the safety and clinical efficacy of hypothermia after hemicraniectomy in malignant MCA infarction. Methods : From October 2012 to February 2016, 20 patients underwent hypothermia (Blanketrol III, Cincinnati Sub-Zero, Cincinnati, OH, USA) at $34^{\circ}C$ after hemicraniectomy in malignant MCA infarction (hypothermia group). The indication of hypothermia included acute cerebral infarction >2/3 of MCA territory and a Glasgow coma scale (GCS) score <11 with a midline shift >10 mm or transtentorial herniation sign (a fixed and dilated pupil). We retrospectively collected 27 patients, as the control group, who had undergone hemicraniectomy alone and simultaneously met the inclusion criteria of hypothermia between January 2010 and September 2012, before hypothermia was implemented as a treatment strategy in Dong-A University Hospital. We compared the mortality rate between the two groups and investigated hypothermia-related complications, such as postoperative bleeding, pneumonia, sepsis and arrhythmia. Results : The age, preoperative infarct volume, GCS score, National institutes of Health Stroke Scale score, and degree of midline shift were not significantly different between the two groups. Of the 20 patients in the hypothermia group, 11 patients were induced with hypothermia immediately after hemicraniectomy and hypothermia was initiated in 9 patients after the decision of hypothermia during postoperative care. The duration of hypothermia was $4{\pm}2days$ (range, 1 to 7 days). The side effects of hypothermia included two patients with arrhythmia, one with sepsis, one with pneumonia, and one with hypotension. Three cases of hypothermia were discontinued due to these side effects (one sepsis, one hypotension, and one bradycardia). The mortality rate of the hypothermia group was 15.0% and that of the control group was 40.7% (p=0.056). On the basis of the logistic regression analysis, hypothermia was considered to contribute to the decrease in mortality rate (odds ratio, 6.21; 95% confidence interval, 1.04 to 37.05; p=0.045). Conclusion : This study suggests that hypothermia after hemicraniectomy is a viable option when the progression of patients with malignant MCA infarction indicate poor prognosis.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.303-310
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• 2015

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.125-137
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• 1996

This study was designed to investigate effects of relative humidity on the breakthrough of charcoal tubes at a fixed vapor concentration and sampling time during mixed organic vapor sampling. A vapor generator was used to generate three different concentrations of mixed organic vapor and a stainless steel chamber was fabricated and utilized to maintain three different percentages of relative humidity while maintaining a constant temperature. The results were as follows; 1. At high relative humidity, breakthrough of mixed organic vapor occurred quickly at low vapor concentration than at high vapor concentration because of the reduced adsorption volume of charcoal tube due to humidity. 2. Breakthrough by competitive adsorption of vapors onto charcoal tube was observed at first from n-hexane having the lowest boiling point and highest vapor pressure among the three organic vapors investigated, followed by TCE. No breakthrough was observed from toluene under all experimental conditions. 3. For n-hexane, breakthrough was observed after 2 hours of sampling and breakthrough rates were increased as relative humidity increased. For TCE, breakthrough was found after 3 hours of sampling and breakthrough rates by sampling time were increased as vapor concentration increased. 4. The adsorbed amount of mixed organic vapor at breakthrough was shown to have statistically significant correlations with sampling time, relative humidity, and vapor concentration in descending order of correlation. Relative humidity and sampling time for n-hexane and sampling time and concentration for TCE were both statistically significantly correlated. 5. Relative humidity was found to affect the amount of breakthrough of mixed organic vapor and n-hexane. Among three percentages of relative humidity investigated, the amount of breakthrough at 85 % relative humidity was significantly larger than those of at lower percentages of relative humidity. No statistically significant difference was found between 25 % and 55 % relative humidity. 6. The results of multiple regression analysis between breakthrough and relative humidity, vapor concentrations showed that the coefficient of determination of mixed organic vapor was 0.263 and those of n-hexane and TCE were 0.275 and 0.189, respectively. 7. Flow rates of sampling pumps used were found to be affected by relative humidity present. At 25 %, 55 %, and 85 % relative humidity, the relative errors of sampling pump were 1.4 %, 13.4 %, and 18.6 %, respectively. In conclusion, the results of this study showed that high relative humidity could reduce the adsorption volume of charcoal tubes and subsequently increase breakthrough rates. Therefore, to prevent breakthrough when sampling mixed organic vapors, it is suggested that either sampling volume be reduced on the flow rate be lowered so as to minimize breakthrough of the most volatile organic vapor in the mixture. In addition, since the flow rates of a sampling pump can be adversely affected by high relative humidity, it is recommended to use a constant flow mode pump when sampling in the highly humid environment.

• Archives of design research
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• v.20 no.1 s.69
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• pp.243-252
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• 2007

Nowadays, technological differences between companies have decreased and products launched show more resemblance to each other. As an alternative plan companies started developing brands. The excellence in quality of a product from a company could be easily copied, but the formless value, brand, cannot be imitated easily. More importantly, in the globally competing generation the brand provides distinctiveness and gives a solution to the relationship between consumers. Also the design image takes a big part in a company's competitiveness. The design image that represents the company reflects the brand, and it reflects the image and the philosophy of the company. And the images of each product influence the brand. Also an effective delivery of a product image would give a synergistic effect on the brand. A company could build this design identity to elevate the brand. Therefore, the identity of design image reflects the brand. Therefore a study on the area of the absence and misled identity of design image is important. This study is fixed on the idea of, development of brand to increase competitiveness, and the affiliation of design image with the identity of the brand. This study, on the basis of preceding research and theoretical background, aims to find the design identity area focusing on the product design image of the product purchased by the consumer. Firstly, we need to examine the affinity of the product image from the consumer, and analyse the direction of images to offer a solution that could advance the design identity strategy.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.35-48
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• 2018

The study of air defense against North Korean tactical ballistic missiles (TBM) should consider the rapidly changing battlefield environment. The study for target re-designation for intercept missiles enables effective operation of friendly defensive assets as well as responses to dynamic battlefield. The researches that have been conducted so far do not represent real-time dynamic battlefield situation because the hit probability for the TBM, which plays an important role in the decision making process, is fixed. Therefore, this study proposes a target re-designation algorithm that makes decision based on hit probability which considers real-time field environment. The proposed method contains a trajectory prediction model that predicts the expected trajectory of the TBM from the current position and velocity information by using random forest and moving window. The predicted hit probability can be calculated through the trajectory prediction model and the simulator of the intercept missile, and the calculated hit probability becomes the decision criterion of the target re-designation algorithm for the missile. In the experiment, the validity of the methodology used in the TBM trajectory prediction model was verified and the superiority of using the hit probability through the proposed model in the target re-designation decision making process was validated.