• Fire Science and Engineering
• /
• v.31 no.6
• /
• pp.16-22
• /
• 2017

In Korea, performance-based fire safety designs are being discussed to deal with the various risks of fire in complex and diverse types of structure. However, performance-based fire safety designs are not actively employed because it is difficult to estimate the fire characteristics related to the various factors in buildings. In this study, real scale fire tests were conducted based on fire severity levels and fire loads provided in He New Zealand Building Code, in order to use the results as guidelines and fundamental data for performance-based designs. In the real scale fire tests conducted in a 10MW full-scale calorimeter, wood cribs were placed in a $2.4(L){\times}3.6(W){\times}2.4(H)m$ mock-up of a compartment which had one $0.8(L){\times}2.0(H)$ opening for different fire loads and heating was continued until all of the wood cribs were burned down. The heat release rate started to increase rapidly 90 seconds after the wood cribs caught fire. In the test with a fire load level 1, the maximum heat release rate of 4743.4 kW was reached at 244 second. In the test with fire load level 2, a maximum heat release rate of 5050.9 kW was reached at 497 second. In the test with fire load level 3, a maximum heat release rate of 4446.9 kW was reached at 677 second.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.6
• /
• pp.1023-1035
• /
• 2016

Suspended sediment concentration (SSC) is a crucial riverine parameter in terms that it can be utilized for analyzing sediment transport, stability assessment of river and structure and so on. However, in case of domestic, sediment discharge data are not enough because of using conventional sediment samplers. This study aimed at developing a practical technique for estimating suspended sediment concentration in high spatial and temporal resolution by building relationship between acoustic backscatter (or SNR) from H-ADCP with actually observed data using LISST-100X. In this regard, a dedicated correction algorithm was proposed particularly for the adapted H-ADCP (SonTek SL-3000). Then, a SNR-SSC relation was built based upon a real-scale field experiment, where both H-ADCP and LISST-100X were concurrently operated to observe SNR and SSC, respectively. The coefficient of determination for the developed regression equation of SNR-SSC relation was around 0.85~0.88, thereby the relation could be evaluated to be highly correlated. The result of this study might be potentially applied for real-time and simultaneous observation of SSC when H-ADCP could be applied.

• Fire Science and Engineering
• /
• v.25 no.1
• /
• pp.7-12
• /
• 2011

As recent buildings are getting more high-rise and larger, steel structures, not a reinforced concrete structure, for columns and beams among the main structural members in a building are being widely used. Steels used for the main members of a building are constructed with a fire-resistive structure by applying them with fire-resistive coatings. The introduction of a simple test method that can verify the performance of fire-resistive material constructed on a site without conducting a fire-resistant test(real scale fire test) is needed and this study derived a site analysis method possible to make a rapid and scientific analysis through the analysis of components (instrumental analysis) concerning tire-resistive materials. the possibility of application of it in analyzing congruence over site construction materials by recognizing it as a standard material after securing an inherent fingerprint area of tire-resistive materials of which performance was verified in the concrete through thermal analysis was proved through experiments. This research result can be minimize of casualties, who is harmed to building collapse according to structures fire.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.2
• /
• pp.315-324
• /
• 2017

The smart grid with distributed power supply introduces a number of problems including not only the problems of the existing power grid but also the problem of protection co-operation due to new electric phenomenon because it has a mixed operation structure combining the existing radial operation structure and the new loop operation structure. The EMTP based power system analysis method has flexibility and convenience from the view of system configuration but it requires another experimental verification because of uncertainty of design and analysis results. On the other hand, the real demonstration system has difficulties in observing accurate fault on large scale system due to considerable economical and spatial construction cost, system configuration constraint, and it is difficult to demonstrate the distributed, autonomous and adaptive control strategy of smart grid. In this paper, a basic theory for a micro smart grid simulator design using MEMS(Micro Electro-Mechanical Systems) miniaturization technology is studied which can safely and freely experiment and observe electrical phenomena, and distribution, autonomous adaptive control strategy for disturbances on 22.9kV smart grid under minimum economic and spatial cost.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.1
• /
• pp.27.2-27.2
• /
• 2011

The Kepler(NASA) and CoRoT(ESA) space telescopes are surveying thousands of exoplanet for finding Earth-like exoplanets with similar environments of the Earth. Then the TPF(NASA), DARWIN(ESA) and many large-aperture ground telescopes have plan for spectroscopic observations of these earth-like exoplanets in next decades. Now, it has been started to simulate the disk averaged spectra of the earthlike exoplanets for comparing the observed spectra and suggesting solutions of environment of these planets. Previous research, the simulations are based on radiative transfer method, but these are limited by optical models of Earth system and instruments. We introduce a new simulation method, IRT(Integrated Ray Tracing) to overcome limitations of previous method. The 3 components are defined in IRT; 1)Sun model, 2)Earth system model (Atmosphere, Land and Ocean), 3)Instrument model. The ray tracing in IRT is simulated in composed 3D real scale space from inside the sun model to the detector of instrument. The Sun model has hemisphere structure with Lambertian scattering optical model. Atmosphere is composed of 16 distributed structures and each optical model includes BSDF with using 6SV radiative transfer code. Coastline and 5 kinds of vegetation distribution data are used to land model structure, and its non-Lambertian scattering optical model is defined with the semi-empirical "parametric kernel method" used for MODIS(NASA) and POLDER(CNES) missions. The ocean model includes sea ice cap structure with the monthly sea ice area variation, and sea water optical model which is considering non-lambertian sun-glint scattering. Computation of spectral imaging and radiative transfer performance of Earth system model is tested with hypothetical space instrument in IRT model. Then we calculated the disk averaged spectra of the Earth system model in IRT computation model for 8 cases; 4 viewing orientation cases with full illuminated phase, and 4 illuminated phase cases in a viewing orientation. Finally the DAS results are compared with previous researching results of radiative transfer method.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.4
• /
• pp.183-189
• /
• 2021

In recent years, active research has been devoted toward developing a monitoring system using ambient vibration data in order to quantitatively determine the deterioration occurring in a structure over a long period of time. This study developed a low-cost edge computing system that detects the abnormalities in structures by utilizing the dynamic characteristics acquired from the structure over the long term for ensemble learning. The system hardware consists of the Raspberry Pi, an accelerometer, an inclinometer, a GPS RTK module, and a LoRa communication module. The structural abnormality detection afforded by the ensemble learning using dynamic characteristics is verified using a laboratory-scale structure model vibration experiment. A real-time distributed processing algorithm with dynamic feature extraction based on the experiment is installed on the Raspberry Pi. Based on the stable operation of installed systems at the Community Service Center, Pohang-si, Korea, the validity of the developed system was verified on-site.

• Journal of Korean Society of Rural Planning
• /
• v.24 no.3
• /
• pp.87-96
• /
• 2018

While cities became bigger and bigger since 1990s, many indiscretely high buildings started to be built in the mountain areas inside a city and in the rural areas in the suburb of each city. To regulate such indiscrete developments, the government prepared for some relevant legal and institutional criteria by having enacted the "Landscape Act" and established a strong management means in the legal and institutional aspects by having introduced the natural landscape deliberation system and the landscape deliberation one into the "Natural Environment Conservation Act." However, since some uniform levels of absolute height and no. of stories are suggested legally and institutionally, it is hard to consider the effects of a real building structure onto the relevant landscape. Accordingly, this thesis is intended to grasp the contrast of the landscape elements in the allowable height section, which is presented through landscape sensitivity. As the results from the visual contrast rating on a small apartment complex located in Dangjin and a large scale of apartment complex in Seosan as the apartment complexes surrounded with natural landscapes that were selected as the subjects of this study, the following conclusion can be finalized. First, there were deducted some factors, that is, forms, lines, colors, textures and sizes as the ones with which can measure and evaluate the contrasting properties when a structure gets into a natural landscape. Second, in case of a small scale of apartment complex (in the foreground) compared to a large one (in the foreground), it was found that the contrasting properties were bigger. In addition, it was also found that the contrasting property of the landscape factor of the foreground compared to that of the middle one becomes bigger depending on a distance. Third, as the results from an evaluation on the contrasting properties of the landscape factor depending on the changes of each floor of a structure, it was found that the factors, that is, forms, lines, colors, textures and sizes are very significant. Among those factors, the factors, forms and lines in a small scale of apartment complex (in the foreground) showed each log regression. But in all of the other cases, they showed each line regression. Fourth, as the results from examining the regression coefficients of the landscape factor, the coefficients of the shapes and lines have similar coefficients and the colors and the textures have similar ones, too. In case of the sizes of apartment complexes, the colors and the textures of a large apartment complex (in the foreground) have similar coefficients, in case of that in the middle ground, the shapes and lines have similar coefficients. Fifth, as the results from estimating the contrasting properties of the landscape factor on the floors within the allowed scope of the landscape sensitivity, it was found that the contrasting property was 3.5 to 4.9 in case of a small scale of apartment complex (in the foreground), but 2.5to 3.7 in case of a small scale of one. In case of a large scale of apartment complex, the value was 3.5 to 5.3, but in case of a large one in the middle ground was 2.9 to 4.9. Sixth, it was comprehended that the contrasting properties of the landscape factor become different depending on each size of apartment complex and the distance of a view point. In this study, it is intended to find the meaning from the aspect that the results can be used as the baseline data for comprehending a proper range of heights of structures objectively during a natural landscape deliberation or a landscape deliberation.

• Journal of Life Science
• /
• v.28 no.3
• /
• pp.284-292
• /
• 2018

The melanin-concentrating hormone (MCH), a cyclic hypothalamic peptide composed of 17 amino acids, was initially identified in chum salmon (Oncorhynchus keta) as a regulator of pigmentation. Mammalian MCHs are cyclic hypothalamic peptides composed of 19 amino acids that regulate food intake and energy homeostasis. The present study examined not only MCH expression of different tissues but also the melanohore aggregation and intracellular $Ca^{2+}$ influx of fMCH and the other MCH. Real-time qPCR showed that MCH expressed specially in the brain, gonad, and ovary, and expression of MCH was observed during the developmental stages. In the application of synthetic fMCH and both types of synthetic fMCH, dN-fMCH and dC-fMCH, scale melanophore induced significant changes in aggregation activity with various concentrations of MCH. Also, compared to hMCH and sMCH, fMCH exhibited a 36~99.85% increase in relative potency (%), whereas aggregation of dN-fMCH and dC-fMCH remained in a high concentration. However, dispersion was induced rapidly according to be low concentration of dN-fMCH and dC-fMCH. We show that fMCH and its derivates were bound human MCHR1 and rat MCHR expressed in HEK293T cells with nano-molar affinity and are likely to be ligand-induced to mobilize intracellular $Ca^{2+}$. These results may provide new ligands for binding assay with MCHew ligands, as a structure similar to the mammalian MCH structure was discovered in fish. Once the fMCH receptor system is in place, it can be compared to the MCH system of mammals in terms of MCH function.

• Smart Structures and Systems
• /
• v.24 no.6
• /
• pp.769-781
• /
• 2019

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

• Journal of the Korea Concrete Institute
• /
• v.19 no.1
• /
• pp.11-18
• /
• 2007

Seismic performance evaluation for dam safety evaluation has been continually conducted. However the behavior analysis for the spillway pier which is known as the weak point of dam is seldom reported. Therefore, this study performed the static loading tests for a prototype structures as elementary tests for the final seismic performance evaluation of dam safety. The prototype of pier structure has 1/20 scale and it adopts to strength model. And cracking loads and ultimate loads of real structures are calculated through numerical analysis using commercial FEM program (ABAQUS). The results of this study show some difference between the results of prototype tests and the results of numerical analysis. Also, the ultimate and cracking loads can be estimated through the prototype loading test and numerical analysis.