• Journal of Chest Surgery
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• v.18 no.4
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• pp.872-880
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• 1985

Myasthenia gravis is a neuromuscular transmission disorder characterized by fatigue and weakness of voluntary muscles. Although the pathogenesis is known as reduction of available acetylcholine receptors at neuromuscular junctions by autoimmune attack, the thymic role in myasthenia gravis is still unclear and under investigation. But thymectomy in the management of myasthenia gravis has become increasingly important since the first successful operation with remission of symptoms in 1939 by Blalock. From January 1983 to June 1985, authors performed 17 thymectomies for patients with myasthenia gravis. Among them, 12 patients were free from thymoma [Croup A] and 5 were coupled with thymoma [Group B]. The results were as follows: 1] Sex distribution was 11 females and 6 males. Mean age of the patients was 32.2 year old. Sex and age distribution by the Group A and B are shown Table 1. 2] Clinical manifestations of ocular symptoms were seen in 5 patients [88.2%], extremity weakness in 13 patients, bulbar weakness in 12 patients and dyspnea in 6 patients. According to the Osserman`s classification, 5 patients were in group IIA, 6 in IIB and 6 in IIC. 3] Pre-operatively, all patients were positive response to the anti-cholinesterase test and 12 patients [92.3%] revealed positive findings in electromyography [EMC] which was done in 13 patients. 4] The postoperative complications were respiratory distress in 3 patients, myasthenic crisis in 2 patients and wound disruption in one patients. 5] Pathologic examination of the thymus showed hyperplasia in 10 patients [90%] and thymoma in 5 patients, of which 4 were mixed type with invasion to the adjacent tissues and one lymphocytic type without invasion. Normal thymus was noticed in only 2 patients. 6] In postoperative evaluations, among the 12 patients c free from thymoma [Group A], complete remission of symptoms was noticed in 3 patients and improvement in 7 patients. But among the 5 patients coupled with thymoma [Group B], only one patients showed improvement [Table 8]. Therefore, remission and clinical improvement were noticed in 11 patients [64.7%] of the all and complete remission was noticed in 3 patients [17.6%].

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.333-340
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• 2012

The current study prepared 9 laboratorial concrete mixes and 3 ready-mixed concrete batches to examine the size and shape effects in compression failure of lightweight aggregate concrete (LWC). The concrete mixes were classified into three groups: normal-weight, all-lightweight and sand-lightweight concrete groups. For each concrete mix, the aspect ratio of circular or square specimens was 1.0 and 2.0. The lateral dimension of specimens varied between 50 and 150 mm for each laboratorial concrete mix, whereas it ranged from 50 to 400 mm with an incremental variation of 50 mm for each ready-mixed concrete batch. Test observations revealed that the crack propagation and width of the localized failure zone developed in lightweight concrete specimens were considerably different than those of normal-weight concrete (NWC). In LWC specimens, the cracks mainly passed through the coarse aggregate particles and the crack distribution performance was very poor. As a result, a stronger size effect was developed in LWC than in NWC. Especially, this trend was more notable in specimens with aspect ratio of 2.0 than in specimens with that of 1.0. The prediction model derived by Kim et al. overestimated the size effect of LWC when lateral dimension of specimen is above 150 mm. On the other hand, the modification factors specified in ASTM and CEB-FIP provisions, which are used to compensate for the shape effect of specimen on compressive strength, were still conservative in LWC.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.257-264
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• 1989

In order to study spatial variability of soil chemical properties across the land-partitioned boundary on Hwadong silt clay loam soil (Fine clayey, mixed, mesic family of Aquic Hapludalfs) in the experimental fie ld of the wheat and Barley Research Institute in Suwon, all measured data were analyzed by means of kriging, fractile diagram, smooth frequency distribution, and autocorrelation. Sampling for soil chemical property analysis was made at 225 intersections of 15x 15 grid with 10m interval from three soil depths (0-10cm, 25-35cm, 50-60cm) in the seven patitioned fields. 1. The coefficient of variance (CV) of various chemical properties varied from 5.4 to 72.7%. Soil pH was classified into the low variation group with CV smaller than 10%, while the other chemical properties belonged to the medium variation group with C.V. between 10 and 100% 2. The approximate number of soil samples for the determination of various chemical properties with error smaller than 10% were two for pH, ten for CEC, 15 for exchangeable Ca, 32 for total nitrogen content, 39 for exchangeable Mg, 40 for exchangeable K, 61 for exchangeable Na, 82 for organic matter content, 212 for available phosphate,. 3. Smooth frequency distribution and fractile diagram showed that available phosphate was in log-normal distribution while others were in normal distribution. 4. Serial correlation analysis revaled that the soil chemical properties had spatial dependence between two nearest neighbouring grid points. Autocorrelation analysis of chemcial properties measured between the serial grid points in the direction of south to north following land-partitioned boundary showed that the zone of influence showing stationarity ranged from 20 to 50m. In the direction of east to west accross land-partitioned boundary, the autocorrelogram of many chemical properies showed peaks with the periodic interval of 30m, which were similar to the partitioned land width. This reveals that the land-partitioned boundary causes soil variability.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.163-172
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• 1989

In order to study spatial variability of soil physical properties accross the land-partitioned boundary on Hwadong silt clay loam soil (Fine clayey, mixed, mesic family of Aquic Hapludalfs), all measured data were analyzed by means of kriging, fractile diagram, smooth frequency distribution, and autocorrelation. Sampling for soil particle size distribution analysis was made at 225 intersections of $15{\times}15$ grid with 10m interval. Field capacity, bulk density and saturated hydraulic conductivity were measured in situ at 594 intersections of $33{\times}18$ grid with 2.5m interval in only $6,000m^2$ reselected from $22,500m^2$ of sampling area for particle size distribution analysis. Sampled or measured soil depths were 0 to 10cm 25 to 35cm and 50 to 60cm at each intersections. The results are summarized as follows: 1. The coefficient of variance (CV) of various physical properties ranges from 4.8 to 128.8%. Saturated hydraulic conductivity is classified into the high variation group with CV greater than 100%, while the low variation group with CV smaller than 10% consists of bulk density. Other properties belong to the medium variation group with CV between 10 and 100%. 2. The appropriate number of soil samples for the determination of various physical properties with error smaller than 10% are calculated as one for bulk density, six for field moisture capacity, 16 for silt, 19 for clay, 69 for sand and 686 for saturated hydraulic conductivity. 3. Smooth frequency distribution and fractile diagram show that saturated hydraulic conductivity is in lognormal distribution while other physical properties are in normal distribution. 4. Serial correlation analysis reveals that the soil physical properties have spatial dependence between two nearest neighbouring grid points. Autocorrelation analysis of physical properties measured between the serial grid points in the direction of south to north following section boundary shows that the zone of influence showing stationarity ranges from 7.5 to 40m. In the direction of east to west across section boundary, the autocorrelogram of many physical properties shows peaks with the periodic interval of 30m, which are similar to the partitioned land width. This reveals that the land-partitioned boundary causes soil variability.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.301-317
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• 1998

A clinical analysis was carried out for 32 patients who were treated in Dept. of Dong-shin Oriental Medicine Hospital from 10st January to 16st May in 1998 and ruled out as dememtia. The results were summarized as follows. 1. In the distribution of sex, female was more than male. And the age of seventies(17 cases, 53.125%) was highest in the frequency of age. 2. In the distribution of having history of drinking and smoking were each 4 cases(12.5%) and 7 cases(21.875%). 3. In the distribution of seasons, the ratio of spring and winter were each 16 cases(50.0%), 15 cases(46.875%), that of summer and fall were comparatively low. 4. In the period from onset to admission, the period within a week had 20 cases(62.5%) as top, and the most period of treatment was 2 and 3 weeks(28.125%). 5. The number of cases that had preceding disease was 35 cases(71.875%), a major portion of preceding diseases were hypertension, diabetes mellitus, stroke. 6. The most common symptom was disorientation(78.125%), and the next common symptom was motor desability(71.875%), and memory disturbance, verbal disturbance was each 59.375 and 47.1%. 7. In the distribution of the CT scan films, 15 cases(46.875%) showed cerebral infarction and that of another 5cases (15.625%) showed cerebral hemorrhage, that of another 2 cases(6.25%) showed brain atrophy. 8. In the lipid density of blood, T-Cholesterol, TG, HDL-Cholesterol, LDL- Cholesterol was within normal limit. 9. In the MMSE-K, the most score was from 16 point to 20 point, and second only was from 11 point to 15 point, and the next was from 6 point to 10 point. 10. In the Ischemic score, 20 cases(62.5%) was diagnosed as brain vascular type dementia, and mixed type dementia was 9 cases(28.125%), Alzheimer type dementia was 3 cases(9.375%). 11. The most used recipes were a sort of recipes to activate of flow the vital energy and the blood, to remove the phlegm(41 cases 33.9%), especially DODAMHOALHEL TANG (12 cases, 9.9%), ANSINCHUNGNOITANG (8 case, 6.6%) was the most used recipe. 12. In the judgement of efficacy, 17 cases(53.125%) showed excellent efficacy, 10 cases(31.25%) showed good efficacy, 5 cases(15.625%) showed no change and that according to MMSE-K, 4 case(18.18%) showed excellent efficacy, 15 cases(68.18%) showed good efficacy, 15 cases(68.18%) showed no change.

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.197-205
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• 2002

The objectives of this Paper is to implement a diagnostic classifier of differential laryngeal diseases from acoustic signals acquired in a noisy room. For this Purpose, the voice signals of the vowel /a/ were collected from Patients in a soundproof chamber and got mixed with noise. Then, the acoustic Parameters were analyzed, and hierarchical neural networks were applied to the data classification. The classifier had a structure of five-step hierarchical neural networks. The first neural network classified the group into normal and benign or malign laryngeal disease cases. The second network classified the group into normal or benign laryngeal disease cases The following network distinguished polyp. nodule. Palsy from the benign laryngeal cases. Glottic cancer cases were discriminated into T1, T2. T3, T4 by the fourth and fifth networks All the neural networks were based on multilayer perceptron model which classified non-linear Patterns effectively and learned by an error back-propagation algorithm. We chose some acoustic Parameters for classification by investigating the distribution of laryngeal diseases and Pilot classification results of those Parameters derived from MDVP. The classifier was tested by using the chosen parameters to find the optimum ones. Then the networks were improved by including such Pre-Processing steps as linear and z-score transformation. Results showed that 90% of T1, 100% of T2-4 were correctly distinguished. On the other hand. 88.23% of vocal Polyps, 100% of normal cases. vocal nodules. and vocal cord Paralysis were classified from the data collected in a noisy room.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.139-151
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• 2021

Purpose To retrospectively evaluate the chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) in patients with mild clinical symptoms at a single hospital in South Korea. Materials and Methods CT scans of 87 COVID-19 patients [43 men and 44 women; median age: 41 years (interquartile range: 26.1-51.0 years)] with mild clinical symptoms (fever < 38℃ and no dyspnea) were evaluated. Results CT findings were normal in 39 (44.8%) and abnormal in 48 (55.2%) patients. Among the 48 patients with lung opacities, 17 (35.4%) had unilateral disease and 31 (64.6%) had bilateral disease. One (2.1%) patient showed subpleural distribution, 9 (18.8%) showed peribronchovascular distribution, and 38 (79.2%) showed subpleural and peribronchovascular distributions. Twenty-two (45.8%) patients had pure ground-glass opacities (GGOs) with no consolidation, 17 (35.4%) had mixed opacities dominated by GGOs, and 9 (18.8%) had mixed opacities dominated by consolidation. No patients demonstrated consolidation without GGOs. Conclusion The most common CT finding of COVID-19 in patients with mild clinical symptoms was bilateral multiple GGO-dominant lesions with subpleural and peribronchovascular distribution and lower lung predilection. The initial chest CT of almost half of COVID-19 patients with mild clinical symptoms showed no lung parenchymal lesions. Compared to relatively severe cases, mild cases were more likely to manifest as unilateral disease with pure GGOs or GGO-dominant mixed opacities and less likely to show air bronchogram.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.230-242
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• 2005

Background : Spirometry should be compared with the normal predictive values obtained from the same population using the same procedures, because different ethnicity and different procedures are known to influence the spirometry results. This study was performed to obtain the normal predictive values of the Forced Vital Capacity(FVC), Forced Expiratory Volume in 1 Second($FEV_1$), Forced Expiratory Volume in 6 Seconds($FEV_6$), and $FEV_1/FVC$ for a representative Korean population. Methods : Based on the 2000 Population Census of the National Statistical Office of Korea, stratified random sampling was carried out to obtain representative samples of the Korean population. This study was performed as a part of the National Health and Nutrition Survey of Korea in 2001. The lung function was measured using the standardized methods and protocols recommended by the American Thoracic Society. Among those 4,816 subjects who had performed spirometry performed, there was a total of 1,212 nonsmokers (206 males and 1,006 females) with no significant history of respiratory diseases and symptoms, with clear chest X-rays, and with no significant exposure to respiratory hazards subjects. Their residence and age distribution was representative of the whole nation. Mixed effect models were examined based on the Akaike's information criteria in statistical analysis, and those variables common to both genders were analyzed by regression analysis to obtain the final equations. Results : The variables affecting the normal predicted values of the FVC and $FEV_6$ for males and females were $age^2$, height, and weight. The variables affecting the normal predicted values of the $FEV_1$ for males and females were $age^2$, and height. The variables affecting the normal predicted values of the $FEV_1/FVC$ for male and female were age and height. Conclusion : The predicted values of the FVC and $FEV_1$ was higher in this study than in other Korean or foreign studies, even though the difference was < 10%. When compared with those predicted values for Caucasian populations, the study results were actually comparable or higher, which might be due to the stricter criteria of the normal population and the systemic quality controls applied to the whole study procedures together with the rapid physical growth of the younger generations in Korea.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.9-18
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• 2013

Two-phase vapor-liquid flows exist in many shell and tube heat exchangers such as condensers, evaporators, and nuclear steam generators. To understand the fluid dynamic forces acting on a structure subjected to a two-phase flow, it is essential to obtain detailed information about the characteristics of a two-phase flow. The characteristics of a two-phase flow and the flow parameters were introduced, and then, an experiment was performed to evaluate the pressure loss in the tube bundles and the fluid-dynamic force acting on the cylinder owing to the pressure distribution. A two-phase flow was pre-mixed at the entrance of the test section, and the experiments were undertaken using a normal triangular array of cylinders subjected to a two-phase cross-flow. The pressure loss along the flow direction in the tube bundles was measured to calculate the two-phase friction multiplier, and the multiplier was compared with the analytical value. Furthermore, the circular distributions of the pressure on the cylinders were measured. Based on the distribution and the fundamental theory of two-phase flow, the effects of the void fraction and mass flux per unit area on the pressure coefficient and the drag coefficient were evaluated. The drag coefficient was calculated by integrating the measured pressure on the tube by a numerical method. It was found that for low mass fluxes, the measured two-phase friction multipliers agree well with the analytical results, and good agreement for the effect of the void fraction on the drag coefficients, as calculated by the measured pressure distributions, is shown qualitatively, as compared to the existing experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.533-536
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• 2008

Recently, in Korea, there has been an increasing number of research papers published which are to improve durability of concrete, particularly by analyzing correlation between diffusivity of chloride and porosity/pore size distribution. In these studies, such test methods as mercury intrusion porosimetry(MIP), gas adsorption or image analysis method are used to analyze the microstructure of materials while MIP is most widely used for concrete. This study analyzes the results of porosity and pore size distribution of paste and concrete adding fly ash or blast furnace slag by using MIP equipment which is widely used for determining micro-porosity structure of cementitious materials. A variation in porosity and pore size distribution at the curing day 3, 7 and 28 has been observed by using MIP equipment for cement paste 35%, 40%, 45%, 50%, 55%, 60% of W/C when using $300kg/m^3$ of cement, 35%, 45%, 55% of W/C when replaced 60% with blast-furnace slag, and 35%, 45%, 55% of W/C when replaced 30% with fly ash. For long-term water cured normal OPC concrete and mixed concrete replaced 60% with blast-furnace slag powder, micro-structure of the sample has been analyzed by using MIP equipment when W/C indicated 40%, 45%, 50% respectively and the binder varied $300kg/m^3$, $350kg/m^3$, $400kg/m^3$, and $450kg/m^3$.