• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.12
• /
• pp.1829-1836
• /
• 2010

The district heating system distributes the heat generated from a cogeneration plant to wider locations. In this process, the district heating pipe (DHP) is subjected to internal and external loadings. The internal loadings are generally caused by the operating conditions such as water temperature and internal pressure. Frictional interactions between the pipes and the soil contribute to the external loadings. Thus, investigation of the mechanisms of failure of DHPs will help to guarantee both mechanical stability and heating efficiency. In this study, we investigate the local buckling of DHPs using limit state design (LSD). Two methods are considered: the use of the limit state for the width-thickness ratio and the use of the limit state for the strain. The results are used to confirm that the DHP is stable under local buckling. Finally, we suggest a minimum preheating temperature for avoiding local buckling.

• Journal of Life Science
• /
• v.19 no.6
• /
• pp.693-697
• /
• 2009

The purpose of the present investigation was to investigate diversity patterns in Mt. Neungdong forested landscape. It was conducted on twelve sloping plots $(100{\times}100 m)$ in the east and west sides of Mt. Neungdong. A total of 2,157 specimins were identified as trees with a diameter at breast height (DBH) ${\geq}$10 em. There were a total of 135 species of 35 families present in both regions of Mt. Neungdong. Least significant differences (LSD) by post hoc analysis revealed that region A had significantly greater densities than region B. Shannon-Wiener functions differed significantly between forests (F=4.12, < 0.05), with region B forest having a significantly higher value (2.118) than region A (1.882). Pinus thunbergii and Quercus aliena were dominant on most plots of both regions, however, the P. densiflora forest of region A was distributed better in the middle plots exposures compared to the opposite ones. Q. aliena, Q. mongolica, and Carpinus laxiflora largely occupied the middle and lower exposures of region B. The spatial distribution in Neungdong's forest was very heterogeneous and reflected by most species as having micro-climate and patchy distributions.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.6
• /
• pp.77-87
• /
• 2013

A present LSD (limited state design) code for temperature load in the domestic bridge design has applied a uniform standard for various bridge types. In this study, in order to calculate the effective temperature, a specimen of steel box girder bridge section with real size dimension was manufactured. For a year, the temperature data were measured at the 18 point in steel deck of steel box girder bridges specimen. Effective temperature within the cross section according to atmospheric temperature was calculated by this experiment data. The analyzed results were very similar correlation when compared with the effective temperature of the Euro Code. Therefore, the effective temperature which calculated based on the present data could be used as the basic data in order to present to the appropriate design criteria for the thermal loads on the domestic bridge design.

• Journal of Korean Association for Spatial Structures
• /
• v.8 no.5
• /
• pp.83-93
• /
• 2008

Space truss is a rational system which forming large span in spatial structure and the steel tube is used well as a structure member in truss system. This study includes coupon test and Stub-column compression test on the structural steel tube. The compression test of Stub-column was performed to characterize and quantify the material characteristic and strength of column. In this study, we also researched the matter of compatibility, in which we compared the experiment formula and the abstract formula by the application of the LSD standard formula, SSRC and ECCS multiple column curve.

• Journal of the Korea Society for Simulation
• /
• v.15 no.1
• /
• pp.27-33
• /
• 2006

To guarantee QoS (Quality of Service), routers should determine routing paths satisfying service requirements, based on link state information as well as network topology. Link status database (LSD) in routers should be efficiently managed to effectively reflect the current state of all links. However, there is a trade off between the exact reflection of the current link status and its update cost. For exactly reflecting the current link status, each router immediately notifies its neighbors that link state information is changed. This may degrade performance of the router due to the processing of link state update messages. On the other side, if the current link state information is not updated appropriately, a route setup request can be rejected because of the discrepancy between the current link state information and previously updated link state information in LSD. In this paper, we propose a traffic variation based link state update algorithm for adaptively controlling the generation of link state update messages and compare its performance with those of four existing algorithms by intensive simulations.

• The Journal of the Society of Korean Medicine Diagnostics
• /
• v.14 no.1
• /
• pp.44-56
• /
• 2010

Objective : To characterize Five Woons of Asian women who live at Los Angeles area in U.S.A Methods : A set of physical tests and diagnostic questions were given to 242 Asian female subjects who were treated for their symptoms at a clinic of Asian medicine near Los Angeles in USA. The participants were given their constitutions, one of the Five Woons based on their birthdays. The physical tests included a body composition via Inbody 4.0 and an autonomic bioelectric response record via ABR2000. The oneway analysis of variance was applied to compare the means of the Five Woons and the physical test results. The Cross tabulation analysis was also applied to look for the effectiveness of Five Woons on the symptoms. Results : 1. In the body composition items, the LSD(least significant difference) showed that there were significant differences between the Soil Woon and the other Four Woons which are Water, Metal, Fire and Wood Woons in weight, fat, body fat %, BMI (p<0.2). 2. Based on the LSD, significant differences were observed among the Five Woons in R5, R6 and R7(p<0.2). 3. The cross tabulation analysis showed the significant effectiveness of the Five Woons on the five symptoms including dizziness, hot and cold, lower body edema, fatigue and to take a medication for high blood pressure out of 24 diagnostic questions (p<0.2). Conclusions : Further clinical research is necessary to develop a more delicate questionnaire and look for ways of characterizing the Five Woons. The diagnosis and corresponding treatment based on the Five Woons should be further studied in view of the Oriental medicine.

• Journal of the Korea Convergence Society
• /
• v.10 no.5
• /
• pp.85-94
• /
• 2019

This study was aimed to identify a study on the effect of chest compressions combined with abdominal drawing-in technique on prevention of back pain and chest compression quality. We tested motion analysis, electromyography, and chest compression quality of 15 paramedics. Data were normalized to SPSS 21.0 (Kolmogorov-Smirnov and Shapiro-Wilk test). The paired t-test was used for the pre- and post-test chest compressions, the one-way ANOVA was used for the analysis of the measurement point-in-time differences, and LSD was used for the post-test. The results of the study showed significant difference in muscle activity and chest compression success rate when the chest pressure was applied with abdomen drawing-in. Therefore, it is necessary to study cardiopulmonary resuscitation education which can increase the chest compression success rate while preventing the back pain of the paramedics in the future.

• Journal of The Korean Association For Science Education
• /
• v.43 no.1
• /
• pp.29-36
• /
• 2023

This study investigates the effects of the operation of science activity program on scientific literacy focusing on science cultural literacy and core competencies for pre-service teachers. 255 pre-service teachers of K University participated, and the effects of the program were examined through a paired-sample t-test with one group pretest-posttest design for science cultural literacy. Only the post-test was conducted on core competency growth perception, and differences in growth perceptions by competency were compared using ANOVA. As a result of the study, the average of pre-service teachers was higher than the pre-test for science culture literacy, and this difference was statistically significant (p<.05). In the core competency growth perception, 70.6% of pre-service teachers reported growth in scientific communication ability, and as a result of the post-hoc test using LSD, it shows statistically significant growth compared to other competencies (p<.05). Through this, it was possible to confirm the educational value of the science activity program as a way to develop pre-service teachers' scientific literacy.

• The Journal of the Acoustical Society of Korea
• /
• v.26 no.6
• /
• pp.259-268
• /
• 2007

This paper contributes to an improvement of the statistical bandwidth extension(BWE) system based on Hidden Markov Model(HMM). First, the existing HMM training method for BWE, which is suggested originally by Jax, is analyzed in comparison with the general Baum-Welch training method. Next, based on this analysis, a new HMM-based BWE method is suggested which adopts the Baum-Welch re-estimation algorithm instead of the Jax's to train HMM model. Conclusionally speaking, the Baum-Welch re-estimation algorithm is a generalized form of the Jax's training method. It is flexible and adaptive in modeling the statistical characteristic of training data. Therefore, it generates a better model to the training data, which results in an enhanced BWE system. According to experimental results, the new method performs much better than the Jax's BWE systemin all cases. Under the given test conditions, the RMS log spectral distortion(LSD) scores were improved ranged from 0.31dB to 0.8dB, and 0.52dB in average.

• Journal of Environmental Science International
• /
• v.17 no.1
• /
• pp.1-6
• /
• 2008

The characters of Castanea crenata community which is associated with human activities recently extended around the field of Saengbiryang-myeon at Sanseong-gun in Gyeongsangnam-do. The C. crenata community and its outskirts were investigated for several ecological parameters and the results can be summarized as fellows. C. crenata is prevailing in the plantation area, whereas Pinus densiflora and Quercus mongolica are prevailing in its outskirts. The mean species diversity of plantation was lower than that of natural forests. In stratification of investigated areas, overstory tree layer was dominant in the zone of plantation and dominant layers in the natural forest were understory tree layer, shrub, and herb. Plant biomass and net production which estimated from degree of green naturality were much higher in natural forests than those of the plantation community. Least significant differences (LSD) post hoc analysis revealed that P. densiflora and Q. mongolica community had significantly greater than densities than C. crenata community.