• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.225-231
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• 2016

Glasshouse heating package technologies to improve energy usage efficiency in winter were developed. Heating package was composed of the ground water source heat pump with heating capacity of 105kW, the aluminum multi-layer thermal curtain with six layers of different materials and the root zone local heater with XL pipes of ${\phi}20mm$. Venlo type glasshouse($461m^2$) with the heating package was compared with the same type and area control glasshouse with the light oil boiler, the usual non-woven fabric thermal curtain with respect to the glasshouse inside temperature, relative humidity, crop growth, and heating energy consumption. The results of test in paprika cultivation glasshouses showed that the air temperature inside glasshouse with aluminum multi-layer thermal curtain was maintained $2.2^{\circ}C$ higher than that of control glasshouse in un-heating night time and the temperature in bed with root zone local heating was $4.7^{\circ}C$ higher than that in bed without local heating. Average heating coefficient of performance(COP) of the ground water source heat pump used in paprika cultivation was 3.7 and the glasshouse inside temperature was maintained at $21^{\circ}C$ of heating set up temperature. The heating energy consumptions per 10a were measured at 14,071L of light oil and 364kWh of electric power for the control glasshouse and 35,082kWh for the glasshouse applied heating package. As results, the heating cost of the glasshouse applied heating package was 87 percent lower than that of control glasshouse. The growths of paprika in glasshouses of control and applied heating package did not show any significant difference.

• Journal of the Korean earth science society
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• v.45 no.3
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• pp.203-213
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• 2024

This study aimed to investigate the seasonal patterns of multiple bar formation in summer and flattening in winter on the macrotidal Sinduri beach in Taean, and to understand the processes their formation and subsequent flattening. Beach profiling has been conducted regularly over the last four years using a VRS-GPS system. Surface sediment samples were collected seasonally along the transectline, and grain size analyses were performed. Tidal current data were acquired using a TIDOS current observation system during both winter and summer. The Sinduri macrotidal beach consists of two geomorphic units: an upper high-gradient beach face and a lower gentler sloped intertidal zone. High berms and beach cusps did not develop on this beach face. The approximately 400-m-wide intertidal zone comprises distinct 2-5 lines of multiple bars. Mean grain sizes of sand bars range from 2.0 to 2.75 phi, corresponding to fine sands. Mean sizes show shoreward coarsening trend. Regular beach-profiling survey revealed that the summer profile has a multi-barred morphology with a maximum of five bar lines, whereas, the winter profile has a non-barred, flat morphology. The non-barred winter profiles likely result from flattening by scour-and-fill processes during winter. The growth of multiple bars in summer is interpreted to be formed by a break-point mechanism associated with moderate waves and the translation of tide levels, rather than the standing wave hypothesis, which is stationary at high tide. The break-point hypothesis for multi-bars is supported by the presence of the largest bar at mean sea-level, shorter bar spacing toward the shore, irregular bar spacing, strong asymmetry of bars, and the 10-30 m shoreward migration of multi-bars.

• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.179-195
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• 2013

The study area, which is located in the southeastern part of the Jirisan province, Yeongnam massif, Korea, is mainly composed of the Precambrian Hadong southern anorthosite complex (HSAC), the Jirisan metamorphic rock complex (JMRC) and Cretaceous sedimentary rock which unconformably covers them. Lithofacies distribution of the Precambrian constituent rocks mainly shows NS and partly NE trends. This paper researched deformational phased structural characteristics of HSAC and JMRC based on the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area was formed through at least three phases of ductile deformation. The first phase ($D_1$) of deformation happened due to the large-scale top-to-the SE shearing, and formed the sheath or "A"-type fold and the regional tectonic frame of NE trend in the HSAC and JMRC. The second phase ($D_2$) of deformation, like the $D_1$ deformation, regionally occurred under the EW-directed tectonic compression, and most of the NE-trending $D_1$ tectonic frame was reoriented into NS trend by the active and passive folding, and the persistent and extensive ductile shear zone (Hadong shear zone) with no less than 2.3~1.4 km width was formed along the eastern boundary of HSAC and JMRC through the mylonitization process. The third phase ($D_3$) of deformation occurred under the NS-directed tectonic compression, and partially reoriented the pre-$D_3$ structural elements into ENE or WNW direction. It means that the distribution of Precambrian lithofacies showing NE trend locally and NS trend widely in this area is closely associated with the $D_1$ and $D_2$ deformations, respectively, and the NS-trending Hadong shear zone in the eastern part of Hadong northern anorthosite complex, which is located in the north of Deokcheon River, also extends into the HSAC with continuity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.141-152
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• 2015

The objective of this study is to estimate shear wave velocity of rockfill materials by making practical use of the micro-earthquake records which are ordinarily obtained at a domestic rockfill dam and to verify its applicability. Micro-earthquake records were obtained at the site of Heongseong dam and Soyanggang dam, which are the existing multi-purpose dams in Korea. In the previous study, the fundamental periods of each dam were already evaluated by analyzing the response spectrum of the observed records. In this study, numerical analyses varying shear moduli of rockfill zone were carried out using the acceleration histories measured at the abutment as input ground motions. From comparison between the fundamental periods calculated by numerical analyses and measured records, the shear wave velocities with depth were estimated. It is found that the effect of different earthquake events on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers' empirical relationships and field test results, applicability of suggested method is verified. Therefore, in case that it is impossible to conduct field tests and estimation is preliminary, the suggested method can be practically used.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.9
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• pp.17-24
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• 2007

In this paper, we propose the sub-cell reuse partitioning among relays as an efficient resource reuse scheme in the relay-based OFDMA systems. If the frequency resource is reused among relays aggressively, we can increase the cell throughput. However, the interferences due to the frequency reuse may cause the fairness decrease due to the SINR degradation especially at the edge of RS sub-cells. In this paper, to make the cell throughput and fairness performance improved at the same time, we propose a sub-cell reuse partitioning scheme that divides a relay sub-cell into inner zone for aggressive reuse and outer zone for sparse reuse. The performance of the proposed scheme has been analyzed by computer simulation. We also applied a scheduling algorithm that can work together with the proposed sub-cell reuse partitioning scheme. Simulation results show that the proposed scheme can improve both the throughput and the fairness performances. In particular, when the scheduling is applied for the improvement of fairness, it is shown that the throughput performance can be enhanced more efficiently by the proposed scheme.

• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.264-276
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• 1981

A simulation procedure which can represent time-dependent nuclear characteristics of TRIGA Mark-III reactor is developed. CITATION, a multi-group diffusion-depletion program, has been utilized as calculational tool. The group structure employed in this study consists of 7 groups: -3-fast and 4-thermal-which is conventionally utilized in TRIGA type reactor analysis. Three-dimensional nuclear characteristics are synthesized by combining results from two-dimensional plane calculation and two-dimensional cylinder calculation, since direct three-dimensional approach is not yet possible. An effort ia made to develope a method which can extract effective zone and group dependent bucklings by neutron diffusion theory rather than conventional zone and/or group independent Ducklings by neutron transport theory, since neutron leakage is quite high for small core such as research reactors. It is turned out that the method developed in this study gives satisfactory results. The calculation is performed under assumptions that all control rods are fully withdrawn, that no samples are inserted in the irradiation holes and that the core is located in the center of the reactor pool. Burnup-dependent variation of core excess reactivity, time dependent change of Xe-135 poisoning and reactivity worth of rotary specimen rack are calculated and compared with operation records. Neutron flux and power distribution as well as neutron spectrum in each irradiation .facility are presented.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.359-366
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• 2007

Recently, analysis researches on durability are focused on chloride attack and carbonation due to increased social and engineering significance. Generally, chloride penetration and carbonation occur simultaneously except for in submerged condition and chloride behavior in carbonated concrete is evaluated to be different from that in normal concrete. Furthermore, if unavoidable crack occurs in concrete, it influences not only single attack but also coupled deterioration more severely. This is a study on analysis technique with system dynamics for chloride penetration in concrete structures exposed to coupled chloride attack and carbonation through chloride diffusion, permeation, and carbonation reaction. For the purpose, a modeling for chloride behavior considering diffusion and permeation is performed through previous models for early-aged concrete such as MCHHM (multi component hydration heat model) and MPSFM (micro pore structure formation). Then model for combined deterioration is developed considering changed characteristics such as pore distribution, saturation and dissociation of bound chloride content under carbonation. The developed model is verified through comparison with previous experimental data. Additionally, simulation for combined deterioration in cracked concrete is carried out through utilizing previously developed models for chloride penetration and carbonation in cracked concrete. From the simulated results, CCTZ (chloride-carbonation transition zone) for evaluating combined deterioration is proposed. It is numerically verified that concrete with slag has better resistance to combined deterioration than concrete with OPC in sound and cracked concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.493-502
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• 2016

This study examines how rock condition affects the variation of the chargeability and electrical resistivity of the rock. In the theoretical study, the relationship correlating chargeability with the variables affecting it is derived. A parametric study utilizing the derived relationship reveals that the size of narrow pores ($r_1$) is the most influential factor on chargeability, and the salinity of pore water ($C_0$) is the second. In the laboratory experiments, small scale rock fracturing zone is modelled using sand stone. Chargeability and resistivity are measured by changing the size of the joint aperture, the location of fractured zone and the existence of clay gouge and/or clay layer which shows lower chargeability than the sand stone layer in the multi-layered ground. Test results show that chargeability is controlled not by the rock fracturing condition but by the size of narrow pore ($r_1$) where each line of current flow passes through. Also, the chargeability decreases with increase of the pore water salinity ($C_0$). In conclusion, the ground condition can be identified more efficiently by measuring the induced polarization along with the electrical resistivity; identifying the existence of sea water, the layered ground and/or the fractured rock becomes more reliable.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.168-185
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• 2015

The thermal-hydrological-mechanical (T-H-M) behavior of rock mass surrounding a large-scale high-temperature cavern thermal energy storage (CTES) at a shallow depth has been investigated, and the effects of hydrological conditions such as water table and rock permeability on the behavior have been examined. The liquid saturation of ground water around a storage cavern may have a small impact on the overall heat transfer and mechanical behavior of surrounding rock mass for a relatively low rock permeability of $10^{-17}m^2$. In terms of the distributions of temperature, stress and displacement of the surrounding rock mass, the results expected from the simulation with the cavern below the water table were almost identical to that obtained from the simulation with the cavern in the unsaturated zone. The heat transfer in the rock mass with reasonable permeability ${\leq}10^{-15}m^2$ was dominated by the conduction. In the simulation with rock permeability of $10^{-12}m^2$, however, the convective heat transfer by ground-water was dominant, accompanying the upward heat flow to near-ground surface. The temperature and pressure around a storage cavern showed different distributions according to the rock permeability, as a result of the complex coupled processes such as the heat transfer by multi-phase flow and the evaporation of ground-water.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.105-113
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• 2009

The interpretation of observed waveform characteristics identified in refraction and wide-angle reflection data increases confidence in the crustal structure model obtained. When calculating traveltimes and raypaths, wavefront methods on a regular grid based on graph theory are robust even with complicated structures, but basically compute only first arrivals. In this paper, we develop new algorithms to compute traveltimes and raypaths not only for first arrivals, but also for fast and later reflection arrivals, later refraction arrivals, and converted waves between P and S, using the modified wavefront method based on slowness network nodes mapped on a multi-layer model. Using the new algorithm, we can interpret reflected arrivals, Pg-later arrivals, strong arrivals appearing behind Pn, triplicated Moho reflected arrivals (PmP) to obtain the shape of the Moho, and phases involving conversion between P and S. Using two models of an ocean-continent transition zone and an oceanic ridge or seamount, we show the usefulness of this algorithm, which is confirmed by synthetic seismograms using the 2D Finite Difference Method (2D-FDM). Characteristics of arrivals and raypaths of the two models differ from each other in that using only first-arrival traveltime data for crustal structure analysis involves risk of erroneous interpretation in the ocean-continent transition zone, or the region around a ridge or seamount.