• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.3
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• pp.33-42
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• 1992

The shear strength of cohesionless Soils results from particle-to-particle friction and structural resistance by interlocking. And, the shear strength of soils is subjected to vary depending on the internal states and external condtions. If the volume change occurring in the soils and stress-strain relationships under the internal and external changes can accrurately he described, it is possible to predict the behaviors of soils. To accomplish these objectives a series of drained triaxial compression tests and isotropic compression test was performed on the Banwol sand at different relative densities ranging from 20% to 80% and different confining pressures ranging from 0.4kgf/cm$^2$ to l2kgf/cm$^2$. The results and main conclusions of the study are summarized as follows; 1.When the relative density or the confining pressure is increased, the maximum deviator stress is increased. The ratio of the maximum deviator stress and the confining pressure is linearly proportional to the relative density. 2.It is observed that the dilatancy depends not only upon its relative density but also the confining stress, and that the maximum deviator stress is obtained after the diatancy occurs. 3.The volume of sands undergoes initial contraction prior to the dilatancy occurred by strain softening. The dilatancy rate eventually approaches the critical state or a constant volume. 4.At lower strains, Poisson's ratio approaches a certain minimum value regadless of the state of materials. At larger strains, however, the ratio is increased as the relative density is increased. 5.It is observed that the modulus of elasticity is linearly proportional to the relative density and the pressure. 6.When the relative density is increased, the friction angle of sands is linearly increased. 7.When the relative density is increased, the expansion index and the compression index are linearly decreased, and the ratio of the two is about 1/3.

• Journal of Energy Engineering
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• v.17 no.4
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• pp.204-211
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• 2008

Polyethylene(PE) pipes have been widely used as they are easy to construct and suitable for economical efficient when they are compared with metal pipelines. This paper studied the effect of various external loadings on stress and deflection of the buried PE pipes using Finite Element Method(FEM). For this purpose, stresses of buried PE pipes were calculated according to the loading condition such as pipe types(pipe diameter $50{\sim}400mm$), burial depths($0.6{\sim}1.2m$) and internal pressures($0.4{\sim}4bar$). As a result, it was founded the effect and relation with each of loading conditions under the buried condition.

• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.143-163
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• 2023

This study aims to analyze the impact of ESG activities on the corporate performance of logistics companies in Korea. To achieve this, the study examines the factors influencing the adoption and implementation of ESG activities, assesses the extent to which ESG activities enhance corporate trust and image, and empirically analyzes the effect of ESG implementation on the corporate performance of logistics companies. An online survey was conducted using Google Forms for Korean logistics companies, and a total of 463 data sets were utilized for PLS structural equation analysis using the SmartPLS 4.0 software tools. The findings of the study are as follows: Firstly, external pressure, specifically government pressure, significantly influences environmental responsibility activities, while investor pressure significantly affects social responsibility activities and governance responsibility activities. Additionally, internal management pressures significantly impact environmental responsibility activities, and employees have a significant influence on all ESG responsibility activities. Secondly, environmental responsibility activities positively affect corporate image, whereas social and governance responsibility activities influence trust and corporate image. Thirdly, trust and corporate image demonstrate significant effects on both financial and non-financial performance. Fourthly, trust significantly mediates the relationship between social responsibility, governance responsibility, and non-financial performance, while image mediates the connection between ESG responsibility and both financial and non-financial performance. The contribution of this study lies in providing practical insights for logistics companies to actively promote ESG activities, thereby establishing a reputation for being environmentally, socially, and governance responsible and gaining customer trust. By doing so, this study aims to raise awareness of the importance of ESG activities in the logistics industry and help companies recognize their significance for sustainable management

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.201-209
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• 1996

Background : Auto-PEEP which develops when expiratory lung emptying is not finished until the beginning of next inspiration is frequently found in patients on mechanical ventilation. Its presence imposes increased risk of barotrauma and hypotension, as well as increased work of breathing (WOB) by adding inspiratory threshold load and/or adversely affecting to inspiratory trigger sensitivity. The aim of this study is to evaluate the relationship of auto-PEEP with WOB and to evaluate the effect of PEEP applied by ventilator (external PEEP) on WOB in patients with auto-PEEP. Method : 15 patients, who required mechanical ventilation for management of acute respiratory failure, were studied. First, the differences in WOB and other indices of respiratory mechanics were examined between 7 patients with auto-PEEP and 8 patients without auto-PEEP. Then, we applied the 3 cm $H_2O$ of external PEEP to patients with auto-PEEP and evaluated its effects on lung mechanics as well as WOB. Indices of respiratory mechanics including tidal volume ($V_T$), repiratory rate, minute ventilation ($V_E$), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), peak inspiratory pressure (PIP), $T_I/T_{TOT}$, auto-PEEP, dynamic compliance of lung (Cdyn), expiratory airway resistance (RAWe), mean airway resistance (RAWm), $p_{0.1}$, work of breathing performed by patient (WOB), and pressure-time product (PTP) were obtained by CP-100 Pulmonary Monitor (Bicore, USA). The values were expressed as mean $\pm$ SEM (standard error of mean). Results : 1) Comparison of WOB and other indices of respiratory mechanics in patients with and without auto-PEEP : There was significant increase in WOB ($l.71{\pm}0.24$ vs $0.50{\pm}0.19\;J/L$, p=0.007), PTP ($317{\pm}70$ vs $98{\pm}36\;cm$ $H_2O{\cdot}sec/min$, p=0.023), RAWe ($35.6{\pm}5.7$ vs $18.2{\pm}2.3\;cm$ H2O/L/sec, p=0.023), RAWm ($28.8{\pm}2.5$ vs $11.9{\pm}2.0cm$ H2O/L/sec, p=0.001) and $P_{0.1}$ ($6.2{\pm}1.0$ vs 2.9+0.6 cm H2O, p=0.021) in patients with auto-PEEP compared to patients without auto-PEEP. The differences of other indices including $V_T$, PEFR, $V_E$ and $T_I/T_{TOT}$ showed no significance. 2) Effect of 3 cm $H_2O$ external PEEP on respiratory mechanics in patients with auto-PEEP : When 3 cm $H_2O$ of external PEEP was applied, there were significant decrease in WOB ($1.71{\pm}0.24$ vs $1.20{\pm}0.21\;J/L$, p=0.021) and PTP ($317{\pm}70$ vs $231{\pm}55\;cm$ $H_2O{\cdot}sec/min$, p=0.038). RAWm showed a tendency to decrease ($28.8{\pm}2.5$ vs $23.9{\pm}2.1\;cm$ $H_2O$, p=0.051). But PIP was increased with application of 3 cm $H_2O$ of external PEEP ($16{\pm}2$ vs $22{\pm}3\;cm$ $H_2O$, p=0.008). $V_T$, $V_E$, PEFR, $T_I/T_{TOT}$ and Cdyn did not change significantly. Conclusion : The presence of auto-PEEP in mechanically ventilated patients was accompanied with increased WOB performed by patient, and this WOB was decreased by 3 cm $H_2O$ of externally applied PEEP. But, with 3 cm $H_2O$ of external PEEP, increased PIP was noted, implying the importance of close monitoring of the airway pressure during application of external PEEP.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.201-207
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• 2016

In this paper, an aluminum pressure vessel (cylinder) for a 200 m water depth is designed and analyzed. Because of their lack of usage in the deep sea, only a few papers about pressure vessels subjected to external pressures have previously been published. Moreover, the high level of imported external-pressure-vessel products limits the academic pursuit. Yet, research on internal pressure vessels is widely available because of their broad usage at onshore. This paper presents the process of basic designing and modelling of pressure vessels using the design rules of American Standard of Mechanical Engineering (ASME) Section VIII Division 1. To promote understanding, finite element analysis (FEA) result of an existing sample cylinder which was not designed by ASME code is compared with the design obtained in this paper. Several methodologies are used for the finite element analysis, including rectangular, cylindrical, and axisymmetric coordinate, to attain an accurate stress result. Same dimensions except the thickness of the cylinder and loading condition of 0.200 MPa was given for the current study. Finally, a rigorous design procedure is added for the bolt and boundary conditions of the cylindrical body and its ends. The obtained stress level satisfies the allowable design stress value specified in the ASME code.

• Journal of Chest Surgery
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• v.39 no.11 s.268
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• pp.815-821
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• 2006

Background: Carotid endarterectomy is an effective treatment modality in patients with severe carotid artery stenosis, but it may result in serious postoperative complications, We analyzed the results of the carotid endarterectomy performed in our institution to reduce the complications related to the card endarterectomy. Material and Method: We analyzed retrospectively the medical records of 74 patients(76 cases) who underwent carotid endarterectomy for carotid artery stenosis by a single surgeon from February 1996 to July 2004. Result: There were 64 men and 10 women. The mean age of the patients was 63.6 years old. Carotid endarterectomy only was performed in 63 cases, carotid endarterectomy with patch angioplasty in 8 cases, and carotid endarterectomy with segmental resection of internal carotid artery and end to end anastomosis in 5 cases. Intra-arterial shunt was used in 29 cases. The mean back pressures of internal carotid arteries checked after clamping common carotid arteries and external carotid arteries were $23.48{\pm}10.04$ mmHg in 25 cases with changes in electroencephalography(group A) and $47.16{\pm}16.04$ mmHg in 51 cases without changes in electroencephalography(group B). There was no statistical difference in the mean back pressure of internal carotid arteries between two groups(p=0.095), but the back pressures of internal carotid arteries of all patients with changes in electroencephalography were under 40 mmHg. When there was no ischemic change of electroencephalography after clamping common carotid artery and external carotid artery, we did not make use of intra-arterial shunt regardless of the back pressure of internal carotid artery. Operative complications were transient hypoglossal nerve palsy in four cases, cerebral hemorrhage occurred at previous cerebral infarction site in two cases, mild cerebral infarction in one case, hematoma due to anastomosis site bleeding in one case, and upper airway obstruction due to laryngeal edema probably caused by excessive retraction during operation in two cases. One patient expired due to cerebral hemorrhage occurring at previous cerebral infarction site. Conclusion: Carotid endarterectomy is a safe operative procedure showing low operative mortality. We suggest that intra-arterial shunt usage should be decided according to the ischemic change of electroercephalography regardless of the back pressure of internal carotid artery. Excessive retraction during operation should be avoided to prevent upper alway obstruction due to laryngeal edema and if upper airway obstruction is suspected, prompt management is essential.

• International Journal of Costume and Fashion
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• v.11 no.2
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• pp.25-36
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• 2011

There seems to have arisen a preference for wearing white clothes amongst Koreans from the long past, even tracing back to the ancient times in tradition of Shamanism worshipping the sun. This "preference" persevered throughout the passage of time, even with the numerous internal and external pressures to forbid or interrupt this tradition. The wearing of White Clothes by Koreans can also be often found in the various records made by foreign visitors recognized as a noticeable phenomenon, and representative of Korea which seems to have influences even until now in the impressions of the country. Despite of this tradition that seems to have lasted over the last 5000 years, all of a sudden it disappeared within the last 50years. In the contemporary modern fashion of Korea, it seems hard to say, Koreans enjoyably sporting White clothes, is a stand out trait anymore, thus the equation of Koreans equivalent to the people of white not a valid stamen anymore. it could not be said that this tradition is representative of the Korean cultural Identity. Why would this be the case? What happened to the long lasted pattern? In what form or shape has this tradition trasnsformed and reappears before us today? This paper seeks to find the answers to these questions.

• Korean Journal of Community Nutrition
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• v.1 no.2
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• pp.178-188
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• 1996

Blood pressure distribution of adolescents and its several related factors including obesity were investigated through blood pressure measuring by automated oscillometric method, anthropometry, and questionnaire. Subjects were 480 female and 480 male middle school students living in Taejon. Mean values of systolic(SBP)/diastolic(DNP) blood pressure of male and female students were 118.4$\pm$11.0/69.5$\pm$9.6 mmHg and 116.9$\pm$10.4/69.5$\pm$8.6 mmHg, respectively. Their blood pressures, particularly SBP, increased with age and showed higher value in the males than in the females. All frequency distributions of SBP and DBP, by sex and age, showed normal curves and their 50th, 90th, and 95th percentiles were presented. As obese index increased, both SBP and DBP were elevated and the prevalence of hypertension which was classified by Task Force Report(1987) increased, particularly in male students. Body weight and BMI were positively correlated with both SBP and DBP, and hight was also positively correlated with SBP or DBP. Our data inicated that blood pressure and hypertension prevalence of adolescents tended to increase and various internal and external environmental factors affected them. It was emphasized that blood pressure measurement should be done in every medical examination of adolescents and the nationwide Korean standard of blood pressure for adolescents have to be prepared. (Korean J Community Nutrition 1(2) : 178-188, 1996)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.3
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• pp.184-193
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• 2001

The present study develops programs simulating the internal pressure change of cars due to the change of external pressure when trains run into or passing each other in a tunnel. A new continuous ventilating system control method has been developed in order to alleviate the aural discomfort of passengers riding a high speed train. This method is based on the change of the charged and discharged flow rate by detecting the air pressures generated outside and inside of the train. When the outside and inside pressure are detected, the speed of the charge or exhaust fans and also the valve opening ratios are changed. The elementary performance of the system is checked using dta of the TGV-K high speed train at a speed of 300km/h. Moreover, applicability of the system to the Koran high speed train at a speed of 350 km/h is ascertained by simulation and its effectiveness as a means to alleviate the ear pains is confirmed. This application of the system to the Korean high speed vehicles running in the speed range of 350km/h is considered to have good prospect.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.56
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• pp.29-54
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• 2012

As market is more and more mature, the survival environment of exporting companies is getting severer, which throws exporting companies into great pressures of the process of growth and development. For most businessmen, the hardest part of starting a foreign business is to find buyers or to get customers, which is more critical for small and medium-size foreign enterprises. The fast changes of internal and external trade and market circumstances, together with the advent of e-commerce, led to the diversified of the way to find foreign buyers for exporting companies. But the performance differs in using different ways of finding foreign buyers. Therefore, this study examines the status of the methods of finding foreign buyers and performance of exporting companies in China. Based on the investigation of the ways of finding foreign buyers, this study tries to find out the most efficient ways of finding foreign buyers for them. And this study tries to propose some practical suggestions for the exporting companies based on the analysis that will help them to improve companies' performances.