• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.23-37
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• 2007

Recently a concept of pile-tip enlarged PHC pile (Ext-PHC pile), for use in the auger-drilled construction method, has been developed and is being implemented in practice. A series of field axial load tests on both PHC and Ext-PHC piles were conducted at an experimental site. In addition, a parametric study on a number of influencing factors was made using a validated finite element model. The field axial load tests indicated an enhanced load-settlement characteristics for the Ext-PHC piles compared with the PHC piles, giving approximately 50% increase in the end bearing capacity. Also found in the results of the parametric study was that the increase in the end bearing capacity of Ext-PHC piles slightly varies with the mechanical properties of supporting ground as well as pile length, in the range of 1.25 to 1.4 time that of PHC. Overall, the results of the field tests as well as the numerical study confirmed that the end bearing capacity of PHC pile can be improved by the concept of.Ext-PHC pile.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.27-37
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• 2010

Downdrag force develops when a pile is driven through a soil layer which will settle more than a pile. There is no obvious criterion for application of the current pile design method considering the negative skin friction. Therefore, in this study, numerical analyses were performed to investigate the behavior of a single pile subjected to negative skin friction and their results were used to determine the applicability of the current design method. Including three different sites in Song-do area and two different cases with friction pile and end bearing pile conditions, total six cases were considered. The load-settlement relationships and the neutral points were estimated for different end bearing conditions and the allowable bearing capacity of piles with negative skin friction was investigated through parametric studies. Based on the results showed that the negative skin friction made a major influence on the settlement of a pile and its stress. However the allowable bearing capacity may not be influenced by the negative skin friction. Compared with the allowable bearing capacity obtained from the ultimate bearing capacity with the safety factor of 3, the current design method with the safety factor of 3 underestimated the allowable bearing capacities regardless of the end bearing conditions. On the other hand, the current design method with the safety factor of 2 yielded reasonable results depending on the end bearing conditions.

• Journal of the Korean Geotechnical Society
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• v.29 no.7
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• pp.17-36
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• 2013

In this paper, the empirical relations of skin friction and end bearing resistance with the results of site investigation in soft rock are proposed through the analysis of bi-directional pile load tests of rock socketed drilled shafts performed at large offshore bridge foundations and high-rise building projects (13 test piles in 4 projects). The site investigation and drilling for bi-directional pile load tests were performed at the centers of test piles, and f-w curves for skin friction and q-w curves for end bearing were plotted based on load-transfer measurements. From the above curves, the empirical relations of skin friction and end bearing resistance with the results of site investigation depending on the mobilized displacement are determined by multiple regression analysis and compared with previous studies. Since the f-w and q-w curves of rock-socketed piles in Korea show hardening behavior according to mobilized displacement, the developed empirical relations by the mobilized displacement are more reasonable than those of previous studies which could not consider the mobilized displacement and suggested the ultimate capacity with unconfined compressive strength only. Particularly, the developed equations correlated with unconfined compressive strength show the best correlations among the equations correlated with other parameters.

• Korean Journal of Veterinary Service
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• v.25 no.4
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• pp.385-407
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• 2002

The planning of any experiment or trial involving the use of animal (material) requires the most detailed and careful consideration of the wide variety of species and strains that are now available. Unfortunately, although many research workers carefully define their requirements with respect to chemicals or complicated laboratory equipment, often they appear to be unaware of the specifications that should be similarly applied to laboratory animals and end up simply asking for a white mouse！ The aim of any user of laboratory animals should be to achieve maximum accuracy with the minimum number of animals, and it is, therefore, essential that careful consideration should be given to the choice of the animal(Bleby J, 1987). The first step when selecting an experimental animal is to specify the type needed, taking into account the following factors: 1. species, 2. breed or strain, and 3. quality, especially with respect to health and genetical status. The correct choice of species cannot be emphasized too strongly and failure to do so can sometimes have dire consequences, frequently very expensive in financial terms and sometimes extremely tragic in manifestations of human and animal suffering. In this paper, we reorganized a lot of collected articles described previously for common and scientific names of amphibians, domestic animals, birds, invertebrates, mammals, reptiles, and aquaculture as mentioned in the text.

• Child Health Nursing Research
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• v.13 no.4
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• pp.495-505
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• 2007

Purpose: The purpose of this paper was to develop a CD program of applied logotherapy to improve the quality of life of adolescents with terminal cancer. Method: Keller's ARCS theory and a model for developing internet learning materials(Kang) was applied to develop this program comprised four distinct phases: planning, designing, development, and execution stages. Results: This program was entitled 'Finding treasures in my life' and consisted of 5 sessions and its educational contents were made up as follows: "Treasure One" is 'learning three natures of the human mind', "Treasure Two" is 'learning creative value as first method to find meaning of life', "Treasure Three" is 'learning experiential value as second method to find meaning of life', "Treasure Four" is 'learning attitudinal value as third method to find meaning of life', and "Treasure Five" is 'Becoming the master of my life'. The sub-menu was made up of 'Beginning', 'What is it?', 'Travelling'. 'Laughing Song', 'End'. Conclusions: This CD program applied logotherapy with flash animation technique as an emotional and spiritual nursing intervention program for easier and more scientific application in pediatric oncology and hospice area.

• Design & Manufacturing
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• v.15 no.1
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• pp.8-13
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• 2021

Excavators are construction machines used for digging soil, transporting soil, dismantling buildings and clearing the ground at construction sites. There are various attachments attached to the arm end of the excavator and used for various operations. There are the most common types of buckets attached for excavation and other types of attachments used for foresting, road cleaning, snow removal, and waste disposal. When multiple types of work are done at the same time, several attachments must be replaced and a device called a quick coupler is used to reduce replacement time. Although a quick coupler reduces the replacement time of the Attachment, it is necessary to attach safety devices to prevent unintentional detachment of attached attachments during the operation. To prevent the attachment from leaving or falling regardless of the operator's intention, support is installed in the hook of the bucket pin and controlled through a separate hydraulic cylinder to ensure safety. When attaching an attachment, it shall be attached without any action. This study is intended to verify the design validity of safety devices to prevent falls of attachments occurring at construction sites.

• Korean Journal of Ichthyology
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• v.20 no.3
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• pp.224-227
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• 2008

A specimen of Aspasma minima (25.4 mm SL) belonging to the family Gobiesocidae was collected from coastal waters near Hamdeok in Jeju Island, Korea. This species is characterized by having 6~9 dorsal fin rays, 5~9 anal fin rays, 20~24 pectoral fin rays, many red spots on head and body when fresh, and posterior end of upper jaw not reaching anterior margin of eye. Our specimen is well matched in its morphological characteristics with previous descriptions of A. minima. Thus, we newly add this species to the Korean fish fauna and propose its new Korean name, "Kkoma-hak-chi".

• Journal of Environmental Science International
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• v.15 no.9
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• pp.881-886
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• 2006

The purpose of this research is to examine the beach erosion prevention capability of submerged breakwaters under wave energy condition. To accomplish this objective, the computational domain was divided into two do-mains : the large and the detailed domain for the Song-Do beach. For each computational domain, numerical models for calculating transformation, wave induced current and beach erosion were used and also these numerical models were carefully applied to three experimental cases such as 1) the present beach condition, 2) the condition for which submerged breakwaters are installed about 240m from the shoreline of beach enlarged by artificial nourishments. The results of this research show that if storm waves attack the present beach, the erosion occurs widely all over the beach. However, when the submerged breakwaters are installed in addition to the artificial nourishments, storm waves can be adequately controlled and strong wave induced currents occur only around the submerged breakwaters resulting in the beach evolution appearing locally only at the western end of the beach.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.1
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• pp.72-81
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• 2009

This paper provides simulational round robin test results for welding residual stress prediction of safety/relief nozzle. To quantify the welding variables and define the recommendation for prediction and determination of welding residual stress, 6 partners in 5 institutes participated in round robin test. It is concluded that compressive axial and hoop residual stress occurs in dissimilar metal weld and pre-existing residual stress distribution in dissimilar metal weld was affected by similar metal weld due to short length of safe end. Although the reason for the deviation among the results was not pursued further, the effect of several key elements of FE analyses on welding residual stress was investigated in this paper.

• Korean Journal of Veterinary Service
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• v.37 no.2
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• pp.97-100
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• 2014

This study was performed in Korea to get serological information for bovine herpesvirus 1 (BoHV-1), most commonly found in cattle. Antibodies against BoHV-1 were examined by targeting infectious bovine rhinotracheitis (IBR) in unvaccinated and vaccinated cattle, using viral neutralization (VN) test. In 2013, among 261 sera collected from IBR-unvaccinated herds, 7 sera (2.7%) were found seropositive and their VN titers were ranging from 1:4 to 1:32. Among 315 sera collected from IBR-vaccinated herds in large capacity farms, 303 sera (96.2%) were found to be seropositive for BoHV-1 and their VN titers were in the range of 1:4 to 1:2048. It was found that the IBR-vaccinated herds had higher levels of VN titer than IBR-unvaccinated herds. The results indicated that it may be due to heavy vaccination in vaccinated herds and no or a little infection in unvaccinated herds. At the end of the study it was concluded that although the seropositivity in IBR-unvaccinated herds was low, the monitoring of IBR should be continuously practiced to control and prevent the disease because of exportation of living cattle causing its nationwide outbreaks.