• Proceedings of the Korean Nuclear Society Conference
• /
• 1999.10a
• /
• pp.189-189
• /
• 1999

• Atmosphere
• /
• v.32 no.4
• /
• pp.395-409
• /
• 2022

A new soil moisture initialization scheme is applied to the Korea Meteorological Administration (KMA) Global Seasonal forecasting system version 6 (GloSea6). It is designed to ingest the microwave soil moisture retrievals from Soil Moisture Active Passive (SMAP) radiometer using the Local Ensemble Transform Kalman Filter (LETKF). In this technical note, we describe the procedure of the newly-adopted initialization scheme, the change of soil moisture states by assimilation, and the forecast skill differences for the surface temperature and precipitation by GloSea6 simulation from two preliminary experiments. Based on a 4-year analysis experiment, the soil moisture from the land-surface model of current operational GloSea6 is found to be drier generally comparing to SMAP observation. LETKF data assimilation shows a tendency toward being wet globally, especially in arid area such as deserts and Tibetan Plateau. Also, it increases soil moisture analysis increments in most soil levels of wetness in land than current operation. The other experiment of GloSea6 forecast with application of the new initialization system for the heat wave case in 2020 summer shows that the memory of soil moisture anomalies obtained by the new initialization system is persistent throughout the entire forecast period of three months. However, averaged forecast improvements are not substantial and mixed over Eurasia during the period of forecast: forecast skill for the precipitation improved slightly but for the surface air temperature rather degraded. Our preliminary results suggest that additional elaborate developments in the soil moisture initialization are still required to improve overall forecast skills.

• The KSFM Journal of Fluid Machinery
• /
• v.14 no.1
• /
• pp.18-23
• /
• 2011

The hydraulic part in reactor coolant pump consists of suction nozzle, impeller, diffuser, and discharge nozzle. Among them, impeller is required to be designed to satisfy performance requirements such as head, NPSHR, and head curve slope at design point. Present study is intended to suggest the preliminary design method sizing the impeller size to satisfy the design requirement particularly including head curve slope at design point. On a basis of preliminary design result, hydraulic components have been designed in detail by CFD and then manufactured in a reduced scale. Experiment in parallel with computational analysis has been executed in order to confirm the hydraulic performance. Comparison results show good agreement with design result, confirming the validity of design method suggested in this study.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.87-92
• /
• 2007

This work describes the installation and preliminary measurements of an electrical resistivity tomography (ERT) system to monitor the injection of recycled water into a confined aquifer in the area of Sindos (Thessaloniki N. Greece). The aim is to provide, through time-lapse ERT measurements and processing, geoelectrical images of rather increased volumetric sampling around and between the holes and to obtain improved understanding of the flow and transport of the injected water. The details about the general setting, the construction and installation of the ERT cables into the boreholes are explained in full. Preliminary measurements involving single and cross-hole ERT measurements were obtained and processed with a 2D inversion algorithm to produce images of the subsurface. Results depict a very good correlation between ERT images and the lithology and resistivity logs; an indication of the reliability of the approach.

• Journal of the Korean earth science society
• /
• v.28 no.7
• /
• pp.891-902
• /
• 2007

This paper aims to develop a Korea wind chill temperature index using an experimental method. For this, the researchers carried out a preliminary experiment in order to of for provisions necessary for the selection and safety of test participants, accuracy of experiment, and readiness for various situations that may occur during experiment. The researchers also investigated test subjects' safety and experiment conditions in which wind speed changes from calm condition into strong wind speed condition under the constant air temperature of $5^{\circ}C$. The results of this study are as follows. With regard to the variation of facial skin temperature such as forehead, cheek, nose, and chin, the skin temperature of cheek closely appears to depend on the change of air temperature and wind speed, exhibit a stable variation trend of skin temperature, and indicate the lowest temperature than any other facial parts. The skin temperature of women tends to be more sensitive than that of man and the skin temperature of human tends to decrease at weak wind speed under constant air temperature. It was also found that it is not necessary to take the influence of standard wind speed into consideration when a wind chill index is developed.

• Journal of Astronomy and Space Sciences
• /
• v.10 no.2
• /
• pp.103-112
• /
• 1993

The KITSAT-1 was successfully launched on August 11, 1992, into a near circular, 1300-km-high orbit with an $66^{\circ}$inclination. The satellite carries a solid state detector module to measure the high energy particle flux originating mostly from the inner radiation belt. We describe here the objectives of the experiment, the detector structure, and the preliminary result.

• Wind and Structures
• /
• v.2 no.2
• /
• pp.119-125
• /
• 1999

The ZG Bridge(preliminary design), with unfavorable aerodynamic stability characteristics, is a truss-stiffened suspension bridge, its critical wind speed of flutter instability is much lower than that of code requirement, In the present paper, based on both aerostatic and aeroelastic section model wind tunnel test, not only effects of some aerodynamic means on aerodynamic stability of its main girder are investigated, but also such effective aerodynamic means of it as flap and plate-like center stabilizer are concluded.

• 연구논문집
• /
• s.24
• /
• pp.27-39
• /
• 1994

lower vibration than in any other small refrigerators. The experimental results of three types of pulse tube refrigerators are presented in this paper. The objectives of this study are to develop the design technology of the double inlet pulse tube refrigerator and acquire its application method. As a preliminary experiment, the refrigeration performances of the basic, orifice and double inlet pulse tube refrigerator were investigated. The lowest temperature obtained in this experiment was 34.4K. The refrigeration capacity at the optimum operating condition of the double inlet pulse tube refrigerator was 23W at 80K.

• International Journal of Internet, Broadcasting and Communication
• /
• v.16 no.2
• /
• pp.218-226
• /
• 2024

According to the actual situation of a university, the emergency evacuation simulation is modeled based on the physical sign, evacuation speed and personnel ratio using the pathfinder software.The experimental construction export utilization rate is compared with the preliminary simulation scenario. The simulation results show that the utilization rate of evacuation stairs and evacuation exits is significantly improved.The optimized solution can provide the most effective evacuation passage, and the research results can provide the basis for the rational planning and management of evacuation passage in university experiment building.

• Journal of Industrial Technology
• /
• v.19
• /
• pp.173-178
• /
• 1999

In many areas of technology there are machines and systems controllable in up to six degrees of freedom. Helicopters and underwater vehicles, industrial robots are among the first representatives of this category. They need six degrees of freedom in order to move and orient within their workspace. An even broader and more explosively growing area is 3D computer graphics and virtual environment. In this work, functions of 3D input device are described and two types of commercial 3D input device are presented. Then, a preliminary experiment of a low cost 6 axis force/moment sensor is presented that can also be sued as a 3D input device. A low cost force/moment sensor and its application in robot teaching experiment is described. It computes the direction of 3 components of the force and 3 components of the moment applied by human holding the sensor by hand. The concept is shown by an experiment where the tool position and orientation of a robot in 3 dimensional space is controlled by the proposed sensor.