• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.725-730
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• 2017

The strength ratio of the main structures of buildings gradually increasing, due to the advances made in analysis and cost saving techniques. In this study, to examine the stability of industry buildings using sandwich panels as roof assemblies, we examine the changes in the moment strength ratio of the main structures caused by increasing the roof load. This study adopts the PEB structure and three H-steel structure as the structural analysis models. In the case where the additional load exceeds about 11% of the roof design load, the strength ratio exceeds 1 for the main structure. In the case where the additional load exceeds about 36%(of the roof design load), the working moment exceeds the plastic moments, which leads to major damage to the structure. This study compares 1) the maximum load according to the purlin spaces, 2) the maximum load by KS, and 3) the maximum load calculated from the test results of the manufacturer.The maximum bearing load of the panels determined by all three methods exceeds the structure failure threshold load of the main structure. This study provides evidence that an unexpected increase in the roof load might cause the whole structure to collapse, due to the failure of the main structural members, before the failure of the roof assemblies. Therefore, information on the structural performance of the sandwich panels is required for the structural design, and the sandwich panels should be considered to be an integral part of the overall structural design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.545-552
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• 2017

Ground subsidence can result in the formation of sinkholes, potholes, settlement of structures, and road subsidence. Road subsidence is described as the sudden collapse of the road surface into subsurface cavities caused by the loss of bearing capacity in the ground, such as the dissolution of limestone by fluid flow in the surface causing the formation of voids leading to subsidence at the surface. Road subsidence occurs about 665 times annually, and this incidence has been increasing until 2013. Damaged underground facilities, management negligence, and lowering of the ground water table have been the causes of road subsidence in Seoul. Seoul metropolitan government announced special management counter plans to relieve the anxieties and make the roads safe for passing. Construction sites, such as excavation works, need to be managed properly because they have strong potential to induce road subsidence. The aim of this study was to identify the main causes of road subsidence and suggest management plans. First, life cycle cost analysis revealed the daytime construction to be more appropriate than nighttime. In addition, by analyzing the limitations of using sand as a backfill material, it is proposed to use a flowable backfill material instead of sand. Finally, to reduce the blind spots, which is a problem in surveying the road pavement conditions of local governments, the road to be managed is divided into several zones, and a specialized agency is selected for each zone and a method of surveying the blind spots through collaboration is suggested.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.54-59
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• 2004

Experiments were carried out to measure the variation of the compass error on ship's head up bearing by magnetic compass and electromagnetic compass on berthing at the pier in order to obtain a basic information on the utilization of autopilot system using electromagnetic compass in fishing boat. The wooden fishing boat, turned on attracting fish lamps of power consumption 85kW, steering magnetic compass and electromagnetic compass indicated westerly compass error with 7$^{\circ}$ and 13 $^{\circ}$~16$^{\circ}$ respectively. The FRP fishing boat, turned on attracting fish lamps of power consumption 130kW, electromagnetic compass indicated easterly compass error 19$^{\circ}$~23$^{\circ}$. The steel fishing boat, turned on ship's navigation equipments of power consumption 225kW, steering magnetic compass indicated westerly compass error with 16$^{\circ}$. While the difference of compass error using electromagnetic compass indicated westerly compass error with 68$^{\circ}$ on the upper deck when the navigation and fishing equipment turn on compare to turn off the equipment, it had easterly compass error with 16$^{\circ}$, 32$^{\circ}$, 20$^{\circ}$ on the forecastle deck, wheel house and compass deck respectively.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.235-246
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• 2003

Since the study of Lee et al.(1994) there have been some case studies on the set-up effect of driven piles in Korea country. However, comprehensive examination on the analyses of the set-up effect with various testing data has not been carried out. In particular, the analysis of the influence of soil type and pile shape on the set-up effect has not been reported. It is necessary to analyse the test results of production piles in order to apply the set-up effect of driven piles for the field engineering. In this study some test piling and analyses were performed to give basic information to the piling design as well as the research on the set-up effect in sandy soils. The analyses on the set-up effect were performed with the monitoring data obtained from the high-strain dynamic loading tests. It was shown that the set-up effect of driven piles was not only affected by soil type but also by soil formation history It turned out that the set-up effect in sandy soils was considerable one that should not be ignored in the field, and that the bearing capacity increase of pile is mainly caused by the increase of shaft resistance. It was shown that the set-up effect of closed pile was larger than that of opened pile in clayey soils, while the set-up effect of opened pile was larger than that of closed pile in sandy soils.

• Applied Microscopy
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• v.36 no.4
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• pp.251-258
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• 2006

Crystal-bearing cells are rarely encountered in the softwoods and their regular occurrence, e.g., in species of Abies, Picea, Ginkgo, and Pinus, is of considerable diagnostic significance. Thus, this study discusses the distribution and types of crystals in North American Abies species to provide additional information for wood anatomy and identification through light and scanning electron microscopies. Prismatic crystals, elongate crystal s, and styloids are identified, in descending order of frequency, in Abies concolor, A. grandis. and A. magnifica, A. nobilis (=A. procera), A. lasiocarpa, and A. amabilis but not in A. balsamea and A. fraseri. Differently from the other species, A. lasiocarpa shows the tendency of more elongate crystals and styloids than prismatic crystals. A. concolor contains crystal sands, prismatic crystals, elongate crystals, and styloids both in the axial and ray parenchyma cells, whereas the other species show prismatic crystals, elongate crystals, and styloids only in the ray parenchyma cells. Ray parenchyma cells containing crystal sand and axial parenchyma cells having crystal sand, prismatic crystals, elongate crystals, and styloids are probably reported here for the first time in A. concolor. In conclusion, the presence or absence of crystals appears to be the most powerful diagnostic character for separating A. concolor, A. grandis, and A. magnifica from A. nobilis (=A. procera), A. lasiocarpa, A. amabilits, A. balsamea, and A. fraseri.

• Journal of the Korea Institute of Building Construction
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• v.11 no.4
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• pp.326-332
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• 2011

Carbon, Aramid, Boron and Glass fibers are used as fibrous materials to promote structural bearing strength. Of these fiber types, carbon fiber is the most commonly used material, and is characterized by having a one-way direction, which is strengthened by tensile strength due to the attached direction only, while other types of fibers are two-way. Therefore, when applied in the field, the attachment direction of fiber is a very important factor. However, when fiber direction is not mentioned in the design drawing, there sometimes is no improvement in structural strength, as the fiber is being installed by a site engineer or workers who lack structural knowledge. The purpose of this study was to propose an optimal direction of carbon fiber through a comparison & analysis of reinforcing efficiency with reinforced experimental columns that used carbon fibers in each of the inclined, horizontal and vertical directions. According to the results, horizontal direction in the reinforced column was improved by 153.43%, but vertical direction was 104.61% only, and it was understood this was due to increased tensile strength along the fiber direction. For this reason, it is necessary to include information regarding fiber direction in design and site management.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.359-367
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• 2009

This study was conducted to provide useful information for the scientific training of spikes and instruction, by analyzing all kinematical variants including time, distance, velocity, angle factors in spike movements of volleyball matches. The subjects were 4 foreigner players, who participated in the V-League of 2008-2009. The conclusion from this study is as follows. Time for a jumping step was .33s, and Angelko had a bit longer takeoff time than other players. In Angelko and Anderson who were leading in attack power, the whole distance of a spike motion was relatively short, less than 4m. The moment when the center of gravity reached the lowest point was when the right foot bearing weight in the jumping step was passing the left foot, and the highest point of gravity was 2.30m, which appeared just before the impact. The horizontal speed of the center of the gravity was highest as 4.19m/s at the beginning of a jumping step, and lowest at the stance phase of the fore foot just before takeoff. The vertical speed of the center of the gravity was lowest after the right foot touched the ground, and highest after the takeoff of the fore foot. Impact was 3.22m, and the highest ball speed was 28.18m/s.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.368-379
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• 2021

Two virulence factors of Helicobacter pylori, cagA and vacA, have been known to play a role in the development of severe gastric symptoms. However, they are not always associated with peptic ulcer or gastric cancer. To predict the disease outcome more accurately, it is necessary to understand the risk of severe symptoms linked to other virulence factors. Several other virulence factors of H. pylori have also been reported to be associated with disease outcomes, although there are many controversial descriptions. H. pylori isolates from Koreans may be useful in evaluating the relevance of other virulence factors to clinical symptoms of gastric diseases because the majority of Koreans are infected by toxigenic strains of H. pylori bearing cagA and vacA. In this study, a total of 116 H. pylori strains from Korean patients with chronic gastritis, peptic ulcers, and gastric cancers were genotyped. The presence of virulence factors vacAs1c, alpA, babA2, hopZ, and the extremely strong vacuolating toxin was found to contribute significantly to the development of severe gastric symptoms. The genotype combination vacAs1c/alpA/babA2 was the most predictable determinant for the development of severe symptoms, and the presence of babA2 was found to be the most critical factor. This study provides important information on the virulence factors that contribute to the development of severe gastric symptoms and will assist in predicting clinical disease outcomes due to H. pylori infection.

• Journal of Korean Foot and Ankle Society
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• v.26 no.2
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• pp.95-102
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• 2022

Purpose: This study was based on the Korean Foot and Ankle Society (KFAS) member survey and aimed to report the current trends in the management of syndesmotic injuries over the last few decades. Materials and Methods: A web-based questionnaire containing 36 questions was sent to all KFAS members in September 2021. The questions were mainly related to the preferred techniques and clinical experiences in the treatment of patients with syndesmotic injuries. Answers with a prevalence ≥50% of respondents were considered a tendency. Results: Seventy-six (13.8%) of the 550 members responded to the survey. The results showed that the most preferred method to diagnose a syndesmotic injury was magnetic resonance imaging (MRI). Intraoperatively, the external rotation stress test and the Cotton test were most frequently used to confirm syndesmotic diastasis. The reduction was usually done by a reduction clamp. One 3.5-mm screw was used most frequently over three cortices at 2~4 cm above the ankle joint. The preferred ankle position during fixation was 0° dorsiflexion. Removal of the syndesmotic screw was routinely done by most surgeons, mainly because of the limitation of movement and risk of screw breakage. Factors that affect suture button selection included non-rigid fixation which enables adequate fixation, early weight-bearing, and an infrequent need to remove the hardware. Inadequate reduction was considered the main factor that affects poor prognosis. Conclusion: This study proposes updated information about the current trends in the management of syndesmotic injuries in Korea. Consensuses in both the diagnostic and therapeutic approach to patients with syndesmotic injury were identified in this survey study. This study may raise the awareness of the various possible approaches toward the injury and should be used to further establish a standard protocol for the management of syndesmotic injuries.

• Journal of Veterinary Science
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• v.21 no.4
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• pp.65.1-65.13
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• 2020

Background: Aleutian mink disease virus (AMDV) causes major economic losses in fur-bearing animal production. The control of most AMDV outbreaks is complex due to the difficulties of establishing the source of infection based only on the available on-farm epidemiological data. In this sense, phylogenetic analysis of the strains present in a farm may help elucidate the origin of the infection and improve the control and biosecurity measures. Objectives: This study had the following aims: characterize the AMDV strains from most outbreaks produced at Spanish farms between 2012-2019 at the molecular level, and assess the utility of the combined use of molecular and epidemiological data to track the possible routes of infection. Methods: Thirty-seven strains from 17 farms were partially sequenced for the NS1 and VP2 genes and analyzed phylogenetically with other strains described worldwide. Results: Spanish AMDV strains are clustered in four major clades that generally show a good geographical correlation, confirming that most had been established in Spain a long time ago. The combined study of phylogenetic results and epidemiological information of each farm suggests that most of the AMDV outbreaks since 2012 had been produced by within-farm reservoirs, while a few of them may have been due to the introduction of the virus through international trade. Conclusions: The combination of phylogenetic inference, together with epidemiological data, helps assess the possible origin of AMDV infections in mink farms and improving the control and prevention of this disease.