• 한국해양학회지
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• v.26 no.2
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• pp.155-168
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• 1991

In order to study the community structure and distribution patterns of primary producers and their relations to abiotic environmental factors, phytoplankton and environmental parameter were determined during the five times from October, 1989 to July. 1990. 159 taxa of phytoplankton have been identified and the most important species group is diatom which contributes to 70.4% of the total number of species. Ratios of phytoplankton group (neritic species, fresh water species, oceanic species) clustered by habitats were 52%, 18%, 12%, respectively, suggesting study area be the typical estuarine environment which is strongly affected by both fresh water discharge and sea water penetration. Species composition could be governed by the variations of salinity. the standing stocks of primary producer in the study area vary with space and time, showing close correlation with water transparency, and exhibit relatively larger than those of other coastal regions in the Yellow Sea. Spectransies diversity also showed large variation with space and time. According to the cluster analysis, the study area could be divided into two regions (inner part and outer part): in fall and winter, outer area affected by the oceanic water, but in spring and summer, inner estuarine area heavily influenced by fresh water.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.371-382
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• 2014

Objectives: This study was undertaken in order to examine how musculoskeletal disorder(MSD) symptoms were affected by particular factors and then to explore control strategies to prevent MSDs in general hospital nurses. Materials: This, as part of a large study, was conducted using a set of information on literature review, questionnaire survey and focus group interview. It obtained prevalence and factors of MSD symptoms and examined how MSD symptoms were distributed and affected by the factors in nurses working at 15 general hospitals across Korea. The factors were personal factors, work organization, nursing tasks, physical factors and psychosocial factors. Results: A total of 501 nurses were determined as subjects. The highest MSD symptom prevalence was 61% for the shoulder, among body parts, followed by leg/feet(55%), low back(51%), neck(42%), wrist(38%), and elbow(21%). Prevalence for the whole body was 80%. Odds ratios ranged from 0.4 to 22.4 in logistic regression analyses. The symptoms were significantly attributed to factor variables such as body mass index, current health status, daily work time, nursing task, pooled-physical factors, ergonomic factors, work load, interpersonal conflict, and job insecurity. Conclusions: Two or more factor variables were significant, depending on body part, for MSD systems in the general hospital nurses. It was noticeable that physical factors, such as pooled-physical factors, ergonomic factors or work load, were selectively significant for MSD symptoms in all body parts, indicating that such information should be used for prevention of MSDs in the hospital sector.

• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.2 s.27
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• pp.237-248
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• 1988

To access the appropriate height of sleeve cap which is required for the basic sleeve pattern according to arm movements, plaster gypsum experiment was performed. Arm movements were 5types ($0^{\circ},\;45^{\circ},\;90^{\circ},\;135^{\circ},\;180^{\circ}$) to the vertical directions in the front. The appropriateness of the pattern was analyzed by measuring clothing pressure. The results obtained were as follows: 1. Increasing the movement angle, sleeve width increased but height of sleeve cap and armhole girth decreased. 2. Increasing the movement angle, the acromion moved to the front part of bodice. 3. On the basis of the result of the height of sleeve cap, the $\frac{AH}{4} +2.5cm$ sleeve basic 4 pattern is suitable for the direction $M_1(0^{\circ}),\;M_2(45^{\circ})$, and the $\frac{AH}{5}$sleeve basic pattern is suitable for the direction $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$. 4. As the movement angle and height of sleevecap increased, the part which receive high pressure increased and the difference between the hightest and the lowest clothing pressure increased. 5. By the variation of movement angle and height of sleevecap, clothing pressure of upperarm was affected more than that of shoulder blade. 6. The clothing pressure of upperarm and shoulder blades were more affected by the height of sleeve cap than the ease of breast area. 7. Considering the clothing pressure of various arm movement, the most appropriate height of sleeve cap for $M_1(0^{\circ}),\;M_2(45^{\circ})$ positions was to use the $\frac{AH}{4}$+2.5cm, and for $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$, was $\frac{AH}{5}$.

• Journal of Environmental Impact Assessment
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• v.11 no.4
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• pp.247-258
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• 2002

This study aimed at verifying the grain-sized distribution of surface deposits in a tidal flat using multi-spectral Landsat TM. In this study, we employed the grain-sized analysis, PCA and unsupervised classification techniques for analyzing the distribution of deposits. As a result in this study, the unsupervised classification method using PCA image was found to be most useful in classifying tidal flat deposits using satellite data. This method is considerably effective in analyzing not only the aspects of distribution in terms of accumulated deposits and erosion, but also the changes in seaside topography and shoreline. The grain-sized distribution analysis indicates that the mud flat inside the Cheonsu-bay tidal flat is distributed, the mixed flat located in the middle, and the sand flat distributed near the sea. The sand flat is dominant around the southern part of Seomot isle and its beach. On the other hand, the mud and mixed flat is dominant on the western part. Likewise, the western coast of Seomot isle and its beach is significantly affected by waves facing the offshore. However, the eastern side of the bay could be a site for the evolution of tidal flat made of fine materials where it is less affected by ocean waves. These results show that multi-spectral satellite data are effective for the classification of distribution materials and environmental impact assessment and continuous monitoring. In particular, the research on environmental deposits can provide important decision-supporting information for decision-making on seaside development, by analyzing the progress of deposits and environmental changes.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.68-74
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• 2017

Characteristics of dissimilar metal welds between alloy steel ASTM A387 Gr. 91 and carbon steel ASTM A516 Gr.70 made with Flux cored arc welding(FCAW) have been evaluated in terms of microstructure, mechanical strength, chemical analysis by EDS as well as corrosion test. Three heat inputs of 15.0, 22.5, 30.0kJ/cm were employed to make joints of dissimilar metals with E71T-1C wire. Post-weld heat treatment was carried out at $750^{\circ}C$ for 2.5 h. Based on microstructural examination, Intragranular polygonal ferrite and grainboundary ferrite were formed only in first layer of weld metal. Another layers consisted of acicular ferrite and $Widmannst{\ddot{a}}tten$ ferrite. The amount of acicular ferrite was increased with decreasing heat input and layer. Heat affected zone of alloy steel showed the highest hardness due to the formation of tempered martensite and lower bainite. Lower and upper bainite were formed in heat affected zone of carbon steel. Tensile strengths of dissimilar metal welds decreased with increasing heat inputs. Dissimilar metal welds showed a good hot cracking resistance due to the low HCS index below 4. The salt spray test of dissimilar metals welds showed that the weight loss rate by corrosion below 170 hours was decreased with increasing heat inputs due to the increase of the amount of acicular ferrite.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.127-135
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• 1999

As part of a study on the effects of dexamethasone and dehydroepiandrosterone (DHEA) on the biological roles of astrocytes in brain injury, this study evaluated the effects of dexamethasone and DHEA on the responses of primary cultured rat cortical astrocytes to lipopolysaccharide (LPS) and antimycin A. Dexamethasone decreased spontaneous release of LDH from astrocytes, and the dexamethasone effect was inhibited by DHEA. However, the inhibitory effect of DHEA on the dexamethasone-induced decrease of LDH release was not shown in astrocytes treated with LPS, and antimycin A-induced LDH release was not affected by dexamethasone or DHEA. Unlike dexamethasone, DHEA increased MTT value of astrocytes and also attenuated the antimycin A-induced decrease of MTT value. Glutamine synthetase activity of astrocytes was not affected by DHEA or LPS but increased by dexamethasone, and the dexamethasone- dependent increase was attenuated by DHEA. However, antimycin A markedly decreased glutamine synthetase activity, and the antimycin A effect was not affected by dexamethasone or DHEA. Basal release of $[^3H]arachidonic$ acid from astrocytes was moderately increased by LPS and markedly by antimycin A. Dexamethasone inhibited the basal and LPS-dependent releases of $[^3H]arachidonic$ acid, but neither dexamethasone nor DHEA affected antimycin A-induced $[^3H]arachidonic$ acid release. Basal IL-6 release from astrocytes was not affected by dexamethasone or DHEA but markedly increased by LPS and antimycin A. LPS-induced IL-6 release was attenuated by dexamethasone but was little affected by DHEA, and antimycin A-induced IL-6 release was attenuated by DHEA as well as dexamethasone. At the concentration of dexamethasone and DHEA which does not affect basal NO release from astrocytes, they moderately inhibited LPS-induced NO release but little affected antimycin A-induced decrease of NO release. Taken together, these results suggest that dexamethasone and DHEA, in somewhat different manners, modulate the astrocyte reactivity in brain injuries inhibitorily.

• Korean Journal of Human Ecology
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• v.12 no.4
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• pp.433-447
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• 2003

Since self-efficacy was suggested by Bandura(1977) as the most important factor that affects human behavior, preceding studies about self-efficacy are frequently related with children, and it is a main stream that only personal factors are chosen as related factors of these studies. Considering we don't have enough studies about family factors that reflect qualitative and relational factors of adolescents' home background, this study was aimed to seize the actual condition of self-efficacy meaning perceived and emotional faith about their own ability. These are our major concerns: 1. What kind of tendency does self-efficacy and appearance stress of adolescents, family functioning show? 2. How strong are relative influences of variables on self-efficacy of adolescents? This study was operated on July and August, 2002, aimed 378 middle school and high school students in Jeon-Nam, Mokpo area. 378 question sheets were used for analysis. Followings are results of this study. First, aimed students' average mark of self-efficacy was 2.09, which meant a normal level. And in low-ranked part, self-control-efficacy was the highest, and confidence task difficulty preference was following. Furthermore, whole self-efficacy showed a little difference from the demographic factor of adolescents. In low-ranked part, however, confidence and self-efficacy showed a somewhat difference. As students grew up, confidence decreased, and male students showed higher self-control-efficacy than female ones. Second, appearance stress and family functioning degree had a strong relation with self-efficacy. Family functioning, had important interrelation not only with whole self-efficacy but also with low-ranked part of self-efficacy. In low-ranked part, self-control-efficacy and task difficulty preference were proportional to the family functioning degree. From these results, we can find that the appearance stress was an actual factor that affected the self-efficacy of adolescents, and their self-efficacy was strongly related with family functioning degree. Accordingly, affirmative emotion in family, harmonic communication among family members and sharing housekeeping works had an immediate influence on elevation of self-efficacy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.981-989
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• 2010

In this study, we introduce a new architecture of fuzzy inference system. In the fuzzy inference system, we use Fuzzy C-Means clustering algorithm to form the premise part of the rules. The membership functions standing in the premise part of fuzzy rules do not assume any explicit functional forms, but for any input the resulting activation levels of such radial basis functions directly depend upon the distance between data points by means of the Fuzzy C-Means clustering. As the consequent part of fuzzy rules of the fuzzy inference system (being the local model representing input output relation in the corresponding sub-space), four types of polynomial are considered, namely constant, linear, quadratic and modified quadratic. This offers a significant level of design flexibility as each rule could come with a different type of the local model in its consequence. Either the Least Square Estimator (LSE) or the weighted Least Square Estimator (WLSE)-based learning is exploited to estimate the coefficients of the consequent polynomial of fuzzy rules. In fuzzy modeling, complexity and interpretability (or simplicity) as well as accuracy of the obtained model are essential design criteria. The performance of the fuzzy inference system is directly affected by some parameters such as e.g., the fuzzification coefficient used in the FCM, the number of rules(clusters) and the order of polynomial in the consequent part of the rules. Accordingly we can obtain preferred model structure through an adjustment of such parameters of the fuzzy inference system. Moreover the comparative experimental study between WLSE and LSE is analyzed according to the change of the number of clusters(rules) as well as polynomial type. The superiority of the proposed model is illustrated and also demonstrated with the use of Automobile Miles per Gallon(MPG), Boston housing called Machine Learning dataset, and Mackey-glass time series dataset.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1271-1281
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• 2009

The heavy snowfall event over the eastern part of Seoul, Korea on Mar. 04, 2008 has been abruptly occurred after the frontal system with the heavy snowfall event had been past over the Korean peninsula on Mar. 03, 2008. Therefore, this heavy snowfall event couldn't be predicted well by any means of theoretical knowledges and models. After the cold front passed by, the cold air mass was flown over the peninsula immediately and became clear expectedly except the eastern part and southwestern part of peninsula with some large amount of snowfall. Even though the wide and intense massive cold anticyclone was expanded and enhanced by the lowest tropospheric baroclinicity over the Yellow Sea, but the intrusion and eastward movement of cold air to Seoul was too slow than normally predicted. Using the data of numerical model, satellite and radar images, three dimensional analysis Products(KLAPS : Korea Local Analysis and Prediction System) of the environmental conditions of this event such as temperature, equivalent potential temperature, wind, vertical circulation, divergence, moisture flux divergence and relative vorticity could be analyzed precisely. Through the analysis of this event, the formation and westward advection of lower cyclonic circulation with continuously horizontal movement of air into the eastern part of Seoul by the analyses of KLAPS fields have been affected by occurring the heavy snowfall event. As the predictability of abrupt snowfall event was very hard and dependent on not only the synoptic atmospheric circulation but also for mesoscale atmospheric circulation, the forecaster can be predicted well this event which may be occurred and developed within the very short time period using sequential satellite images and KLAPS products.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.1
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• pp.61-71
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• 1994

This study is to investigate the stress distributions, crystal orientations and magnetic properties during die-upsetting according to working temperature of Nd-Fe-B-Cu alloys. The stress distributions in the specimens during compressing process were calculated by a finite element method program(SPID). The calculated stresses were effective stress (${\sigma}_{eff}$), compression stress(${\sigma}_z$), radial direction stress(${\sigma}_r$) rotational direction stress(${\sigma}_e$) and shear stress(${\tau}_{rz}$). The stress distributions of ${\sigma}_z$, obtained by a computer simulation showed that the stress components causing the magnetic alignment during die-upsetting of the cast magnets were very high at the center-part of a specimen, and decreased toward the periphery-part of a specimen. In view of the above results the magnetic properties should be better at the center-part of a specimen than any other parts. But the measured magnetic properties were better at the mid-part. These results should be due to the fact that the specimens were casted. Normally the magnetic properties are affected by the casting process as well as by the stress levels. ${\sigma}_r$, ${\sigma}_e$ are thought to affect the liquid phase flowing and domain patterns, respectively. The influence of ${\tau}_{rz}$ was trivial, ${\sigma}_{eff}$ distributed similar throughout the specimen. The Nd-rich phase appeared at the peripheral of the specimen where the stress level of ${\sigma}_r$, ${\sigma}_z$, was low or the stress level of ${\sigma}_e$ was high. The Nd-rich phase was squeezed out during die-upsetting. This phase had an effect on the crystal orientation and grain growth. The stress distributions of alloy were irregular at the parts of the specimen where the die contacted with specimen.