• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.15-18
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• 2001

Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1089-1092
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• 1999

Applications using 3D models are increasing recently. Since 3D polygonal models are structured by a triangular mesh, the coding of polygonal models in strips of triangles is an efficient way of representing the data. These strips may be very long, and may take a long time to render or transmit. If the triangle strips are partitioned, it may be possible to perform more efficient data transmission in an error-prone environment and to display the 3D model progressively. In this paper, we devised the Component Based Data Partitioning (CODAP) which is based on Topological Surgery (TS). In order to support the error resilience and the progressively build-up rendering, we partition the connectivity, geometry, and properties of a 3D polygonal model. Each partitioned component is independently encoded and resynchronization between partitioned components is done.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.582-588
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• 2005

An experimental study to establish a standard of sump model test of pump station was implemented. Comparison of foreign standard was also performed. Configuration condition around a bell mouth suction intake was easily adjusted by 3-axis traversing system and partition allocation. Operational condition was also varied widely to give accurate test data. PIV was also introduced to produce Quantitative analysis of flow field such as free-surface vortex and submerged vortex occurring in the model test. More detailed vortex behaviors were represented by PIV analysis.

• KSTLE International Journal
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• 제1권1호
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• pp.63-68
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• 2000

Angular contact ball bearings are mainly used in the spindle, which requires high speed and stiffness. The heat generation is studied by experiments and simulations using a pair of angular contact ball bearings. The temperature variation of inner and outer races and the temperature increment distribution are measured by using thermocouples for the rotational speed, preload, viscosity of lubricant. The measured values from experiments are used to estimate the heat conduction rate. The method of oil-air lubrication is used for the experiment. The amount of conduction heat transfer to the test spindle and the convection heat transfer coefficients long the spindle are computed by using inverse method with temperature increment distribution. Total heat generation rate is estimated with the heat partition rate which is calculated from temperatures of inner and outer races. In addition, the empirical factor of oil-air lubrication method for Palmgren's heat generation model is suggested. The empirical friction coefficients, which are obtained from the experiments, depend on the preload condition, and can give us more accurate estimation of the heat generation in ball bearings.

• 한국지능시스템학회논문지
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• 제18권2호
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• pp.262-267
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• 2008

The focus of this paper is on devising an efficient clustering task for arbitrary color data. In order to tackle this problem, the inherent uncertainty and vagueness of color are represented by a fuzzy color model. By taking a fuzzy approach to color representation, the proposed model makes a soft decision for the vague regions between neighboring colors. A definition on a three-dimensional fuzzy color ball is introduced, and the degree of membership of color is computed by employing a distance measure between a fuzzy color and color data. With the fuzzy color model, a novel fuzzy clustering algorithm for efficient partition of color data is developed.

• 한국수소및신에너지학회논문집
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• 제9권3호
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• pp.119-125
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• 1998

The modified statistical-mechanical theory for dense fluid mixtures of rigid spheres has been applied to rigid sphere fluids in the nonoverlapping pore model. The resulting expressions for the partition coefficient and diffusivity illustrate the influence of steric hindrance on the thermodynamic and transport properties in such systems. The open membrane model without the size-exclusion and shielding effects shows considerable overestimation of the diffusion flux when the effective mean pore radii of the order of $20{\AA}$ or less are involved. Theoretical predictions investigated here were also compared with experimental data for hydrogen gases in inorganic porous membranes and it was observed a qualitative agreement in the low pressure limit.

• Journal of Information Processing Systems
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• 제17권1호
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• pp.28-36
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• 2021

This paper proposes two novel methods to model and simulate a mobile Internet of Things (IoT) system using the discrete event system specification (DEVS) formalism. In traditional simulation methods, it is advantageous to partition the simulation area hierarchically to reduce simulation time; however, in this case, the structure of the model may change as the IoT nodes to be modeled move. The proposed methods reduce the simulation time while maintaining the model structure, even when the IoT nodes move. To evaluate the performance of the proposed methods, a prototype mobile IoT system was modeled and simulated. The simulation results show that the proposed methods achieve good performance, even if the number of IoT nodes or the movement of IoT nodes increases.

• Environmental Analysis Health and Toxicology
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• 제16권4호
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• pp.223-226
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• 2001

Acetanilide is a High Production Volume Chemical, which is produced about 2,300 tons/year in Korea as of 1998 survey. Most is used as an intermediate for synthesis of pharmaceuticals and dyes. The chemical is one of seven chemicals, which are under the frame of OECD SIDS program sponsored by National Institute of Environmental Research of Korea. Regarding the information on the environmental fate. bioconcentration is one of important factor to estimate the environmental tranfer. However, measurement of bioconcentration needs high expense and time. For this reason, OECD recommends to use BCFWIN model to estimate bioconcentration of organic chemicals, BCFWIN estimates the bioconcentration factor (BCF) of an organic compound using the log octanol-water partition coefficient (Kow) of the compound. Structures are entered into BCFWIN through SMITES (Simplified Molecular Input Line Entry System) notations. The BCFWIN method classifies a compound as either ionic or non-ionic. ionic compounds include carboxylic acids, sulfonic acids and salts of sulfonic acids, and charged nitrogen compounds (nitrogen with a + 5 valence such as quaternary ammonium compounds). All other compounds are classified as non-ionic. In this study, bioaccumulation of acetanilide was estimated using BCFWIN model based on SMIIES notation, chemical name data and partition coefficient as one of environmental fate/distribution of the chemical elements.

• 대한화학회지
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• 제8권2호
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• pp.68-74
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• 1964

물은 용융점, 끓는점, 용융열 및 증발열등의 수소와 6족원소와의 화합물의 성질로부터 예측되는 값보다 훨씬 크고, ice-I녹을 때 부피의 감소가 일어나는 등 특이한 성질을 가지고 있다. 이와같은 성질들을 정량적으로 설명하려고 지금까지 많은 연구자들이 노력해왔다. 저자들은 물의 큰 표면자유에네르기와 용융시의 특수한 부피변화로 미루어 물의 구조모델을 다음과 같이 생각하였다. 즉, 얼음이 용융함에 따라 분자크기의 이동성 빈자리가 도입되면 물의 큰 표면에네르기 밀도로 말미암아 빈자리 주위의 물분자는 촘촘한 배열을 가지게 되면 빈자리에서 떨어져있는 분자는 ice-I의 구조를 가질것으로 생각된다. 빈자리 주위의 분자가 빈자리에 뛰어 들어갈 때는 이동자유도를 지니게 될 것이다. 저자들은 H. Eyring의 액체구조이론을 써서 물의 liquid partition function을 위에 말한 바와 같이 구조모델로부터 유도하고 물의 증기압, 용융 및 증발엔트로피 등 여러가지 열역학적 성질 및 몰부피를 계산하여 실측치와 좋은 일치를 얻었다.

• 전기학회논문지
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• 제58권1호
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• pp.173-180
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• 2009

It is difficult to predict non-stationary or chaotic time series which includes the drift and/or the non-linearity as well as uncertainty. To solve it, we propose an effective prediction method which adopts data preprocessing and multiple model TS fuzzy predictors combined with model selection mechanism. In data preprocessing procedure, the candidates of the optimal difference interval are determined based on the correlation analysis, and corresponding difference data sets are generated in order to use them as predictor input instead of the original ones because the difference data can stabilize the statistical characteristics of those time series and better reveals their implicit properties. Then, TS fuzzy predictors are constructed for multiple model bank, where k-means clustering algorithm is used for fuzzy partition of input space, and the least squares method is applied to parameter identification of fuzzy rules. Among the predictors in the model bank, the one which best minimizes the performance index is selected, and it is used for prediction thereafter. Finally, the error compensation procedure based on correlation analysis is added to improve the prediction accuracy. Some computer simulations are performed to verify the effectiveness of the proposed method.