• Proceedings of the KSME Conference
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• 2001.06c
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• pp.293-298
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• 2001

In this paper, film thickness and temperature distribution are measured in EHL point contact at high roll/slip ratios. Infrared temperature mapping with two band pass filters, proposed by Ausherman (1976), is used to measure temperature distribution. And the optical interferometric method with two filters (red and green filters) is used to measure film thickness. Result of experiment showed that temperature rising at film and ball surface occurred very dramatically in Dimple zone. As slip velocity, roll/slip ratio and load increased, size of Dimple and temperature rising became more large. In addition, position and shape of Dimple were changed by roll/slip ratios, and increasing of Dimple size decreased traction coefficient. In short, it is appointed that the Dimple phenomenon be developed by the effect of viscosity wedge.

• Clean Technology
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• v.13 no.4
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• pp.237-243
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dimethyl ether (DME) and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing DME as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of DME and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the DME composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature.

• Journal of the Korea Computer Graphics Society
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• v.30 no.3
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• pp.1-8
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• 2024

We present a novel algorithm for creating 2D maps tailored for autonomous navigation within orchards. Recognizing that fruit trees in orchards are typically aligned in rows, our primary goal is to accurately detect these tree rows and project this information onto the map. Initially, we propose a simple algorithm that recognizes trees from point cloud data by analyzing the spatial distribution of points. We then introduce a method for detecting fruit tree rows based on the positions of recognized fruit trees, which are integrated into the 2D orchard map. Validation of the proposed approach was conducted using real-world orchard point cloud data acquired via LiDAR. The results demonstrate high tree detection accuracy of 90% and precise tree row mapping, confirming the method's efficacy. Additionally, the generated maps facilitate the development of natural navigation paths that align with the orchard's layout.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.297-309
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• 2007

The first Korean geostationary weather satellite, Communications, Oceanography and Meteorology Satellite (COMS) will be launched in 2008. The ground station for COMS needs to perform geometric correction to improve accuracy of satellite image data and to broadcast geometrically corrected images to users within 30 minutes after image acquisition. For such a requirement, we developed automated and fast geometric correction techniques. For this, we generated control points automatically by matching images against coastline data and by applying a robust estimation called RANSAC. We used GSHHS (Global Self-consistent Hierarchical High-resolution Shoreline) shoreline database to construct 211 landmark chips. We detected clouds within the images and applied matching to cloud-free sub images. When matching visible channels, we selected sub images located in day-time. We tested the algorithm with GOES-9 images. Control points were generated by matching channel 1 and channel 2 images of GOES against the 211 landmark chips. The RANSAC correctly removed outliers from being selected as control points. The accuracy of sensor models established using the automated control points were in the range of $1{\sim}2$ pixels. Geometric correction was performed and the performance was visually inspected by projecting coastline onto the geometrically corrected images. The total processing time for matching, RANSAC and geometric correction was around 4 minutes.

• The Korean Journal of Mycology
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• v.24 no.3 s.78
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• pp.228-236
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• 1996

Flesh fungi were collected during field trips to mountain areas throughout the country from May to October of 1994. Through the observation and identification of specimens belonging to the Aphyllophorales, one genus, Tylospora, and six species, Athelia fibulata, Hypochnicium punctulatum, Tylospora fibrillosa, Stereum ochraceo-flavum, Steccherinum litschaueri, and Oligoporus undosus were confirmed new to Korea and are registered here with descriptions.

• Water for future
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• v.26 no.2
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• pp.99-105
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• 1993

A practical flood forecasting model(FFM) is suggested. The output of the model is the results which the initial condition of meteorological parameters and soil moisture are projected on the future. The physically based station model for rainfall forecasting(RF) and the storage function model for runoff prediction(RP) are adopted respectively. Input variables for FFM are air temperature, pressure, and dew-point temperature at the ground level and the flow at the rising limb(FRL). The constant parameters for FFM are average of optimum values which the past storm events have. Also loss rate of rainfall can predicted by FRL.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.88.1-88.1
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• 2010

2001년부터 목성, 토성, 타이탄을 관측하여 얻은 근적외선 고분산 분광선에 대한 자료들을 요약하고, 이들 데이터에서 도출된 연구 결과들을 정리하였다. 특히 3 마이크론 근처에서 혜성이나 성간물질 등에서 종종 나타나는 C-H stretching band와 비슷한 분광구조를 확인하였다. 이 분광구조는 행성계 물체의 연무나 구름 입자 속에 포함하고 있는 유기분자 때문이라고 유추된다. 이 파장 영역은 강한 대기 흡수 때문에 많은 관측자들이 기피하던 영역이었는데, 근래에 들어 고분산 분광기의 발달로 대기흡수선 사이를 통해 이들 천체들의 자세한 분광구조를 알 수 있게 되었다. 이번 발표에서 목성, 토성, 타이탄 분광 구조의 다른 점과 같은 점을 보여주고, 이 파장 영역에서만 도출할 수 있는 유용한 과학적 결과를 강조하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.210-220
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• 2003

This work presents a method of point to surface assignment fur 3D metrology of solder pastes on PCB. A bounding box enclosing the solder paste tightly on all sides is introduced to avoid incorrect assignment. The shape of bounding box fur solder paste brick is variable according to geometry of measured points. The surface geometry of bounding box is obtained by using five peaks selected in the histogram of normalized gradient vectors. By using the bounding box enclosing the solder pastes, the task of point-to-surface assignment has been successfully conducted, then geometrical features are obtained through the task of surface fitting.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.542-547
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• 2010

n-Paraffin and saturated fatty acid methyl esters in the diesel and bio-diesel fuel crystallize at low temperature. Many articles have addressed various solutions for the low temperature crystallization problem and one of them is the use of methacrylate copolymers. In this work, we synthesized a series of copolymers in the reaction condition of 70 : 30 molar ratio of lauryl methacrylate (LMA) (or stearyl methacrylate (SMA)) and alkyl methacrylates. The structures of the copolymers were characterized by $^1H$-NMR and FT-IR spectroscopy, and the molecular weight of copolymers were obtained from Gel Permeation Chromatography (GPC) method. The concentrations of additives were 500~1000 ppm and 1000~10000 ppm in diesel fuels and bio-diesel fuel (BD5 and BD20), respectively. The addition of copolymers changes the many properties of fuel such as the pour point (PP), cloud point (CP) and cold filtering plugging point (CFPP). For example, the low temperature properties of the copolymers containing SMA ($PSMAmR_2n$) were excellently improved about 15, 7, and $10^{\circ}C$ for PP, CP and CFPP, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.107-114
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• 2010

Lightning is the discharging of high-voltage charged cells within clouds to earth other or to the earth. Lightning protection grounding is essential for the protection of buildings, distribution lines, and electrical equipment from lightning surges. Equipment grounding is for the purpose of controlling the voltage to earth within predictable limits. This paper investigates the effects of lightning arrester grounding resistance by analysing the neutral to earth voltages and arrester break down voltages when the lightning strike hits the distribution line. The case study was simulated numerically and graphically through the use of the EDSA software program.