• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.19-28
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• 2005

Long span structures with low natural frequencies such as shopping malls, large offices, and assembly rooms may experience signification dynamic responses due to human activities. In many cases, the group activities are common thing in comparison with the single activity. The purpose of this study is to evaluate the responses of building structure subjected to group human loads using mode shapes. For this purpose, equations to estimate the magnitudes ol responses ol structure subjected to group walking loads are derived. And the correlation of loads is verified for identifying the relation of each human load composing of group human loads using two load cells. The method is proposed for evaluating the responses of structure subjected to group loads using mode shapes and correlation function related to each human loads. The effectiveness ol the proposed method is verified analytically using a simple beam and floor and experimentally on a footbridge measuring the structural response induced by group pedestrians for the case of synchronization or not. Results indicate that the amplitudes of group walking loads can be easily estimated if the mode shapes are available, and that the corresponding structural responses can be estimated easily by the simple response measurement using the proposed method.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.106-106
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• 2002

미토콘드리아는 세포내의 에너지대사에서 중요한 역할을 수행하는 세포내 소기관이며, 자체의 유전물질이 모계를 통해 유전되는 특징을 가지고 있다. 포유류 초기 배아의 발생과정에서 미토콘드리아의 역할과 기능에 대한 연구는 미진한 상태이다. 본 연구에서는 생쥐 초기 배아의 발생과정에서 관찰할 수 있는 미토콘드리아 미세구조의 변화 양상을 살펴보고, 이와 초기 배아의 발생 능력과의 관련성을 밝혀보고자 하였다. 과배란 유도된 ICR 생쥐로부터 배란된 난자와 2-세포기 배아를 수획하여 76 배양액으로 포배기까지 체외배양하면서, 각각의 발생단계에 따라 시료를 수획하였다. 미토콘드리아 미세구조의 변화는 일반적인 투과전자현미경방법(TEM)을 이용하여 관찰하였다. 미토콘드리아의 미세구조는 배란 난자에서 4-세포기 배아까지는 구형이고 크리스타가 발달하지 않은 원시형태였지만, 포배기로 발달함에 따라 크리스타가 발달된 막대형의 전형적인 미토콘드리아로 분화됨이 관찰되었다. 체외배양 중에 발생이 지연되거나 정지된 배아에서 관찰한 미토콘드리아의 미세구조는 공포화 (vacuolization), 크리스타 발달 지연, 손상된 미토콘드리아의 세포막 등과 같은 비정상적인 변형을 관찰할 수 있었다. 또한, 극체에 존재하는 미토콘드리아의 미세구조는 정상적인 핵내의 유전자와의 상호작용이 없어 미분화 상태로 포배기까지 유지되는 것을 관찰하였다. 이상의 결과를 통해 미토콘드리아의 정상적인 분화 과정이 초기 배아의 발생능력과 관련되어 있음을 알 수 있었으며, 포유류 초기 배아의 체외배양시스템을 개선하는데 미토콘드리아 미세구조의 관찰과 변화에 대한 고려가 있어야 될 것으로 생각된다. buffer A 용액으로 세척하여 유리 petri dish의 바닥에 부착된 macrophage만을 cell scraper로 분리하였다. 분리한 macrophage는 0.5-1 $\times$ $10^{6}$ cells/$m\ell$가 되게 조정하여, IL-I 을 0.001, 0.01, 0.1 또한 1 ng/$m\ell$를 첨가하여 농도에 따른 효과를 조사하였고, 각각 24, 48, 72, 96 또한 120시간을 배양하여 시간에 의한 효과도 실시하였다. 각 배치구에서 얻어진 배양액은 TGF-$\beta$를 조사하기 전까지 -2$0^{\circ}C$에 동결 보존하였다. TGF-$\beta$의 측정은 TGF-$\beta$ kit(promega, USA)를 이용하여 실시하였으며, 통계학적 분석은 Anova test를 Statview program을 이용하여 분석하였다. 시험의 결과 대조구에 비해 IL-I 첨가구는 2-3배의 TGF-$\beta$생산을 보였으며, 배양시간에 따른 생산은 시간이 지남에 따라 약간 상승하는 경향을 보였으나, 유의적인 차이를 보이지는 않았다. 또한 IL-I의 농도에 따른 생산의 변화는 IL-I의 농도에 따라 약간의 차이를 보였고 유의적인 차이는 인정되지 않았다. 임신 및 비임신의 경우 임신우의 비장 macrophage가 비임신보다는 약간 상승하는 거스로 나타났다. 이상의 결과로 볼 때 IL-I $\alpha$ 는$\bet

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.4
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• pp.439-450
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• 2003

Flat plate system has been adopted in many buildings constructed recently because of the advantage of reduced floor heights to meet the economical and architectural demands. Structural engineers commonly use the effective beam width model(EBWM) in practical engineering for the analysis of flat plate structures. However, in many cases, when it is difficult to use the EBWM, it is necessary to use a refined finite element model for an accurate analysis. But it would take significant amount of computational time and memory if the entire building structure was subdivided with finer meshes. An efficient analytical method is proposed in this study to obtain accurate results in significantly reduced computational time. The proposed method employs super elements developed using the matrix condensation technique and fictitious beams are used in the development of super elements to enforce the compatibility at the interfaces of super elements. The stiffness degradation of flat plate system considered in the EBWM was taken into account by reducing the elastic modulus of floor slabs in this study. Static and dynamic analyses of example structures were performed and the efficiency and accuracy of the proposed method were verified by comparing the results with those of the refined finite element model and the EBWM.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.341-350
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• 1997

The objective of this study is to investigate the structural behavior of the composite slabs with the new metal deckplate. The new deckplate can be used as structural member with topping concrete. So several experiments of this structural test and the fire resistance test were done. From this experiments. slabs with new metal deckpklate were verified as composite slabs. In this paper, this verifications were compared with the international design methods. For experiment. 49 specimens were made. the main parameters are deckplate thickness (1.2mm. 1.6mm) depth of topping concrete(85mm. 90mm). support condition(simple, 2-span), shear reinforcment(studs), span(2.7m, 3.0m, 3.3m. 3.6m. 3.9m) and shear span(L/3, L/4, L/7). We analyzed the structural behavior of composite slab throughout the moment-curvature relationship which is obtained with the program using the computer language. Turbo C. From this development for slab system, the reinforced concrete or steel structure building may be easy, economical for construction, And informations about the structural behavior of composite slabs will be utilized to established korea standard.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.875-882
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• 2021

To minimize occupational noise induced hearing loss, it is recommended that workers should not be exposed to noise levels exceeding 85 dBA for over 8 h. In the present study, noise exposure levels were measured for seven workers based on their tasks on a training ship. The A-weighted noise exposure level (L_ex,24h) was measured by taking into account the A-weighted equivalent continuous sound level (L_Aeq,i), duration (h) and noise contribution (L_ex,24h,i) from the workers' locations. Results are thus obtained for different job categories as follows: officer group L_ex,24h=56.1 dB, navigation crew L_ex,24h=58.9 dB, navigation cadet L_ex,24h=62.0 dB, ship's cook L_ex,24h=64.3 dB, engine cadet L_ex,24h=91.1 dB, engineer L_ex,24h=91.1 dB, and engine crew L_ex,24h=95.1 dB. It was determined that the engineers, engine crews, and engine cadets in charge of machinery must wear hearing protection devices. By wearing hearing protection devices when working in highly noisy engine rooms, it is estimated that the noise expose levels could be reduced by the following amounts: engineer L_ex,24h=23.1 dB, engine Crew L_ex,24h=24.4 dB, and engine cadet L_ex,24h=21.5 dB. Moreover, if the no. 2 lecture room and mess room bottom plates in the cadets accommodations were improved to the 64 mm A-60-class floating plates, then further reductions are possible as follows: navigation cadet L_ex,24h=4.3 dB and engine cadet L_ex,24h=1.8 dB.

• Spatial Information Research
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• v.7 no.1
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• pp.1-12
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• 1999

The DTM(Digital Terrain Model) in GIS(Geographical Information System) shows the elevation from interpolation using data points surveyed. In panoramic flat landform, pixel size, resolution of source data may not be the problem in using DTM However, in mountainous landform like Korea, appropriate resolution accuracy of source data are important factors to represent the topography concerned. In this study, the difference in contour interval of source data, the resolution after interpolation, and different data structures were compared to figure out the accuracy of slope calculation using DTM from the topographic maps of Togyusan National Park Two types of GIS softwares, Idrisi(grid) ver. 2.0 using the altitude matrices and ArcView(TIN) ver. 3.0a using TIN were used for this purpose. After the analysis the conclusions are as follows: 1) The coarser resolution, the more smoothing effect inrepresenting the topography. 2) The coarser resolution the more difference between the grid-based Idrisi and the TIN-based ArcView. 3) Based on the comparison analysis of error for 30 points from clustering, there is not much difference among 10, 20, 30 m resolution in TIM-based Airview ranging from 4.9 to 6.2n However, the coarser resolution the more error for elevation and slope in the grid-based Idrisi. ranging from 6.3 to 10.9m. 4) Both Idrisi and ArcView could net consider breaklines of lanform like hilltops, valley bottoms.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.176-181
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• 2013

The impacts of habitats changes of benthic macroinvertebrae species and individuals of the torrents due to construction of torrent structures can be summarized as follows. Approximately 16 to 40 species and 352 to 4,333.3 individuals of benthic macroinvertebrae were found around the local position of the torrent structures. Construction of torrential structures can increases the stability in the riverbed by preventing vertical corrosion and reducing the flow rate. However, if pond is created due to increase flow rate of rainfall, the temporal confusion of micro-habitats may lead to decrease in the number of species and induce reduced number of diversity as well as cause simplification in the community structure. Therefore, erosion control structures in torrent cause influence on the habitual ecosystem, though there are differences in the degree per distance depending on the types and heights of the structure. Before establishing torrent erosion control structure in mountainous torrent area, ecosystem status should be studied carefully from the planning stage and torrent habitats should be protected by deciding type, height and scale of structure, to minimize the influence on local habitants.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.135-144
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• 2011

Collections were made monthly using beam trawl from March 2005 to February 2006 in Gujora, and from June 2006 to May 2007 in Geoje Bay to investigate the species composition of Juvenile and Immature Fishes of both coastal areas. Fishes collected in the sandy shore of Gujora were 6 orders, 14 families, 20 species, 224 individuals, and 534.9 g in total. Favonigobius gymnauchen, Trachioncephalus myops, Pseudoblennius percoides, Sagamia geneionema, Repomucenus beniteguri, and Pseudorhombus cinnamoneus were mainly collected. These 6 species accounted for 83.9% of total individuals and 47.1 % of total biomass. On the other hand, fishes collected in Geoje Bay were 4 orders, 8 families, 14 species, 1,406 individuals and 1,899.7 g in total. Acentrogobius pflaumii, Platyce phalusindicus, Chasmichthy dolichognathus, Acanthogobius flavimanus, Gymnogobius urotaenia, and Synechogobius hasta were mainly collected. These 6 species accounted for 97.7% of total individuals and 96% of total biomass. The greatest numbers and biomass of fishes were collected in summer and the lowest in winter. In Geoje Bay, the number of species and individuals reached the peak in September and August, respectively. However, both species and individual numbers were highly fluctuated in Gujora.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.1-8
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• 2019

Steel elevator pit was developed for the purpose of minimizing the excavation, simplifying the construction of the frame and economical efficiency by improving the problems that occurred in the existing reinforced concrete. It is common to apply conventional RC method through excavation to underground structures such as underground floor collector well and elevator pit. In recent years, the use of steel collector well and steel elevator pits to reduce construction costs by minimizing the materials of steel and concrete has been continuously increasing. The steel elevator pit is an underground structure and then the performance of the welding part and the structure system is important. Specimen with only steel plate and concrete without studs could support the load more than 3 times than the specimen with deck only. Therefore, even if there is no stud, the deck (steel plate) rib is formed and the effect of restraining the steel plate and the concrete during the bending action can be expected. However, since sudden fracture in the elevator pit may occur, stud bolt arrangement is necessary for the composite effect of steel plate and concrete. It is expected that the bending strength can be expected to increase by about 15% or more depending with and without stud bolts.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.67-77
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• 2022

In South Korea, U-type girder development was attempted as a means to increase the length of I-type girder, but due to the large self-weight according to the post-tension method, the application of rail bridges of 30m or less is typical. There are not many examples of application of pre-tension type girder. This study does not limit the post-tension method, but applies the pre-tension method to induce a reduction in self-weight and materials used due to the reduction of the cross-section. In addition, we intend to apply the on-site pre-tensioning method using the internal reaction arm of the U-type girder. The prestressed concrete U-type girder bridge is composed of a concrete deck slab and a composite section. Compared to the PSC I-type, which is an open cross-section because the cross section is closed, structural performance such as resistance and rigidity is improved, the safety of construction is increased during the manufacturing and erection stage, and the height ratio is reduced due to the reduction of its own weight. Therefore, it is possible to secure the aesthetic scenery and economical of the bridge. As a result, it is expected that efficient construction will be possible with high-quality factory-manufactured members and cast-in-place members. In this paper, the introduction of the pre-tension method on-site and the analytical performance verification of the anchoring block for tension are included.