• Tunnel and Underground Space
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• v.24 no.5
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• pp.354-365
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• 2014

The horizontal response spectra using the observed ground motions from 15 Fukuoka earthquake series, including main earthquake (2005/03/20; Mw=6.5), were analysed and then were compared to both the seismic design response spectra (Regulatory Guide 1.60), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings (1997). 178 horizontal ground motions, without considering soil types, were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that response spectrum have strong dependency on epicentral distance. The results also showed that the horizontal response spectra revealed higher values for frequency bands at two frequency bands (about 8 - 10 and 16- 20 Hz) than Regulatory Guide 1.60. The results were also compared to the Korean Standard Building Design Spectrum for the 3 different soil types and showed that thehorizontal response spectra revealed higher values for almost all period bands than the Korean Standard Response Spectrum (500 yrs; Return Period; Seismic province 1; SE soil conditions). Through the qualitative improvements and quantitative enhancement of the observed ground motions, the diversity of the observed ground motions should be considered more significantly to improve the certainty of response spectrum.

• Korean Journal of Ichthyology
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• v.12 no.1
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• pp.71-84
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• 2000

Annual reproductive cycle of the file fish, Thamnaconus modestus (Gunther), was histologically investigated. Samples were collected monthly in the coastal waters of Chungmun, south of Cheju Island, Korea from July 1997 to June 1999. In males and females of T. modestus GSI values reached the maximum in June and May, respectively. Reproductive cycle could be divided into the following successive stages: in females, growing stage (March to April), mature stage (April to May), spawning stage (May to June), degenerative and resting stage (July to February), and in males, growing stage (January to March), mature stage (April to May), spent stage (May to June), degenerative and resting stage (July to December), respectively. To clarify the spawning cycle of female in T. modestus, some were examined, that is, the weekly changes of GSI, detail developmental stages in the ovary and the weekly changes of sex steroid hormones ($E_2$ and T) levels in plasma during the spawning period. Throughout histological observation of the ovary during the spawning period, T. modestus belonged to an asynchronous and multiple spawner. Changes of plasma $E_2$ and T levels were similar to the changes of GSI and ovary maturity.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.53-68
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• 2015

Longitudinal strain is an important component of seismic design for buried pipelines. A design procedure which determines the wavelength from site natural period and shear wave velocity of the soil layer and closed-form solutions of pipelines under a harmonic motion is typically used in design. However, the applicability of the procedure has not yet been thoroughly investigated. In this paper, displacement-time histories extracted from 1D site response analyses are used in 3D shell-spring model to accurately predict the response of pipelines. The results are closely compared to those from the design procedure. The area of interest is East Siberia. Performing a site response analysis to determine site specific displacement time history is highlighted. The site natural period may be used to predict the predominant period of the acceleration time history, but cannot be used to estimate the predominant period of the displacement time history. If an accurate estimate of the predominant period of the displacement time history is provided, it is demonstrated that the design equation can be successfully used to predict the response of pipelines.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.3
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• pp.183-191
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• 2002

In general, the salient features of the floating breakwater have excellent regulation of sea-water keeping the marine always clean, up and down free movement with the incoming and outgoing tides, capable of being installed without considering the geological condition of sea-bed at any water depth. This study discusses the three dimensional wave transformation of the floating breakwater moored by piers, and its dynamic response numerically. Numerical method is based on the boundary integral method and eigenfunction expansion method. It is known that pier mooring system has higher absorption of wave energy than the chain mooring system. Pier mooring system permit only vertical motion (heaving motion) of floating breakwater, other motions restricted. It is assumed in the present study that a resistant force as friction between piers and floating pontoon is not applied far the vertical motion of the floating breakwater. According to the numerical results, draft and width of the floating breakwater affect on the wave transformations greatly, and incident wave of long period is well transmitted to the rear of the floating breakwater, And the vertical motion come to be large for the short wave period.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.545-557
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• 2020

With the increasing interest on K-fashion all over the world, it's the important time to create the items which can express the unique identity of Korea for promoting the globalization of Korean fashion. Accordingly, this study aims to suggest the modern applicability of traditional patterns by designing the bags using the Dancheong patterns(traditional multi-colored decorative painting) which can effectively express Korean images in a variety of shapes and definite visual features and then expand the scope of fashion items. To this end, this study concentrated on expressing the Dancheong patterns to fit to the modern fashion trends by re-interpreting them. The bag was designed using the laser cutting technique, without weaving or digital printing, to imbue the technical emotion and 3D effect to the patterns. In accordance with the analysis results, the features of patterns could be delicately expressed around the shaping and structuring method in terms of the design, and the scope of design for leather goods could be expanded using the laser cutting in technical aspects. For the industrial aspects, it is required to develop differentiated goods expressing the unique emotion of the Korean for globalization of Korean design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.709-714
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• 2017

Structures like bridges or buildings need to be checked continuously to diagnose their safety. However, it is extremely difficult for the people who access such structures to check all areas directly. To overcome this problem, there is a lot of active research into structural health monitoring (SHM) with wireless sensor nodes (WSNs). In this paper, for more accurate checking of SHM with WSNs, we experimentally compare and evaluate the performance of Xenomai, which provides real-time processing under the traditional Linux kernel. For this purpose, we patch Xenomai into the traditional Linux kernel of a commercial embedded board, Raspberry Pi, and implement a task that periodically reads vibration data of the z-axis from an accelerometer in order to analyze the natural frequency of cantilever beams. Reading the data from the traditional Linux kernel with the same method, we analyze the natural frequency of the cantilever beams using Smart Office Analyzer. Finally, to review the validity of Xenomai for WSNs, we obtain vibration data on the z-axis from the accelerometer via wired network and compared and analyzed them the same way.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.201-205
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• 2001

설악산 국립공원지역 산간계류의 17지점에서 2000년 6월부터 2001년 6월까지 어류상 및 이화학적 요인 분석을 실시하였다. 모든 조사지점은 1-3차 이내의 하천으로 비교적 물리ㆍ화학적 교란이 적었으며 하천폭은 5～30 m 정도였다. 채집된 어류는 총 17과 42종 2,557개체였고, Cyprinidae는 16종 2,165개체가 채집되어 84.7%의 상대풍부도를 나타냈으며, Cobitidae는 5종으로 Cyprinidae 다음으로 가장 많은 종이 채집되었으나 개체수는 109개체로 4.2%의 상대풍부도를 보였다. Gobiidae가 4종 (5.0%), Salmonidae는 모두 3종 (0.8%)이 채집되었다. 이외에도 Oryziatidae, Plecoglossidae, Amblycipitidae, Cottidae, Serranidae 등 12과는 각각 1종씩 모두 117개체 (4.6%)가 채집되었다. Cyprinidae는 전체 채집종의 37.2%를 나타냈다. 우점종은 Zacco temmincki로 10개 지점에서 738개체가 채집되어 28.9%의 상대풍부도를 나타냈으며, 아우점종은 Moroco kumtangensis와 Z.platypus로 각각 4개 지점 648개체 (25.3%)와 7개 지점 344개체 (13.5%)로 나타났다. 한국고유종 (Korean endemic species)은 모두 4과 11종 781개체로 30.5%의 상대풍부도를 나타냈으며, 고유화 빈도는 25.6%로 한국의 평균 고유화 빈도와 유사하게 나타났다 우점종은 M. kumkangensis (한국고유종 중 83.1%)로 나타났으며, 아우점종은 Coreoperca herzi (5.8%), Microphysogobio longidorsalis (3.8%)와 Coreloeuciscus splendidus (2.6%)로 나타났다. 본 조사에서 외래어는 채집되지 않았다. 어류의 다양성은 국립공원내에서보다 하천폭이 커지고 서식처자 비교적 다양한 경계지역의 하천 조사지점에서 더 높게 나타났다.따라서 국립공원의 경계지역에 대한 효율적인 생태적 관리가 요구되며, 국립공원 내의 어류의 다양성 유지와 회복을 위해서는 공원 내는 물론 경계지역 산지하천의 물리적 변형 (보, 제방, 석축 등)과 오염원의 유입 (점, 비점오염원)에 대한 고려가있어야 한다.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.147-153
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• 2012

Precise estimation f a structure's dynamic characteristics is indispensable for ensuring stable dynamic response during life time especially for the structures which can experience resonance such as railway bridges. Especially, concrete track can change the modal properties of the railway bridge, through the contribution of stiffness as well as mass effects, generally only the mass effect is considered in dynamic analysis of the railway bridge. In this paper, static and dynamic behaviors of railway bridge with concrete track were investigated through experimental study. Also, numerical analysis was performed about considering only mass of concrete track and together with stiffness and mass of concrete track. These were compared with experiment value. Numerical analysis value considering together with stiffness and mass of concrete track was similar experiment value. Therefore, when dynamic analysis of railway bridge with concrete track is performed, the contribution of stiffness as well as mass effects for concrete track is considered.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.861-868
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• 2011

Flowmeters that measure the amount of fluid passing through conduits must kept accurate by comparison and the periodic calibration. The reference meters used are clamp-on meters that mount sensors on the outer wall of the pipe. They are called 1-path, 2-path or 4-path flowmeters depending on the number of sensors. We selected a flowmeter mainly used for K-water as test a flowmeter. We carried out experiments to find the intrinsic error of the flowmeter and errors in the downstream of a double bent pipe. The results show that there are the sensor locations that meet the tolerance. We suggested the angle of the sensor, the straight run from the downstream of the bent pipe and the number of sensors. So it is possible to improve the water treatment process and increase the accounted water rate by upgraded flow measurement technology.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.563-570
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• 2015

The existing research on the damage detection method for building structures has considered the damages from the excessive loadings such as the earthquake. However, the structural performance of building structures could be reduced due to the deterioration based on the chloride, carbonation during the long-term time. Thus, to effectively manage the healthiness of structures, the deterioration influences on the structures should be checked. In this study, the corrosion of rebars by the chloride is considered as the deterioration factor. To consider the structural performance reduction of the corroded rebars, the yield strength, cross-sectional area, rupture strain of rebars and the compressive strength of cover concrete based on the corrosion level are estimated. These properties of rebars and cover concrete are used for the procedure to evaluate the structural performance reduction of structural member level and the building level. The moment-curvature analysis is performed to evaluate the structural performance reduction of structural member level. Also, the eigenvalue analysis and the pushover analysis are performed to investigate the natural period and mode shape and the strength and deformation performance of buildings, respectively.