• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1996.06c
• /
• pp.792-801
• /
• 1996

A thinning algorithm -based image analysis technique was developed to measure corn root lengths. The root length measurement method was evaluated by comparing thread lengths measured by the image analysis system with actual thread lengths. The length measurement method accurately estimated actual thread lengths (less than 2% calculated error). Also, a rapid root length density measurement procedure, which utilizes the above root length measurement method, was developed to estimate corn root length density without washing the roots. Root length densities estimated from the cut soil surface of core samples taken from the field were paired with the root length densities determined from washed roots from the same soil core sample. A linear relationship between these two values was expected and was found. Eliminating the root washing procedure reduces the time required for measuring corn root length density substantially.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.20 no.2
• /
• pp.153-160
• /
• 2002

Two different commercial brand X-ray films are used for examining possible differences caused by different target distances when the patients are examined with highenergy X-rays. 6MV- and 15MV X-rays are tested at four different target distances. The films on which the radiation amounts are gradually increased using H$_2$O phantoms are developed by an automatic developing machine to be analysed in the image densities. Characteristic curves have similar shapes for different conditions but for the 130cm target distance. ${\gamma}$ values and average image densities per the illuminated radiation are used to analyse the differences.

• Textile Coloration and Finishing
• /
• v.19 no.6
• /
• pp.7-11
• /
• 2007

A prediction model for yarn density profile was developed using the neural network methodology. The neural network model developed traces mass densities of a yarn within a section and predicts the mass profiles of the next yarn segment yet to be measured. The model does not require an assumption on the existence of a relationship between the past and future data sets. Four high-draft yarns made under different processing conditions were employed in order to test the performance of the model developed. It was shown that the model could predict the yarn density profiles without a significant error.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.3-6
• /
• 2003

We have developed a small-sized superconducting magnetic energy storage (SMES) device, which provides electric power with high quality to sensitive electric loads. In large magnets such as the SMES magnets the stability, which is determined by several factors, e.g. conductors cooling condition and operating current, magnets winding structure, is a crucial problem. The effect of the cooling condition, the copper ratio, and the conductor's size upon the recovery currents was investigated experimentally. The results indicate that the recovery current characteristics of the strands vary considerably according to their insulation method. In the fully insulated strands with a low copper ratio, the recovery current densities range from 10 to 20 % of their engineering critical current densities. The recovery current density of the 30-conductor with a cooling channel is about a factor of 1.8 higher than that without a cooling channel.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.12 no.1
• /
• pp.17-33
• /
• 1986

The interfacial Properties of ferrosoferric oxide suspended in aqueous KNO3 solution are investigated by studying the zeta potentials and surface charge densities at $25^{\circ}C$. The zeta potentials are obtained by measuring the electrophoretic mobility and the surface charge densities by potentiometric titrations in the aqueous KNO3 solutions of different concentrations from 10-3 to 10-1M. The data are interpreted by the surface dissociation and complexation model of Davis, et als. and the modified model.

• Nuclear Engineering and Technology
• /
• v.43 no.3
• /
• pp.287-300
• /
• 2011

Counting statistics modified by introducing two dead times in series under a Poisson input distribution are discussed. A previous study examined the two cases of series combinations of nonextended-extended (NE-E) and extended-extended (EE) dead times. The present study investigated the remaining two cases of extended-nonextended (E-NE) and nonextended-nonextended (NE-NE) dead times. For the three time origins of the counting processes - ordinary, equilibrium, and shifted processes - a set of formulae was newly developed from a general formulation and presented for the event time interval densities, total densities, and exact mean and variance of the counts in a given counting duration. The asymptotic expressions for the mean and variance of the counts, which are most convenient for applications, were fully listed. The equilibrium mean count rates distorted by the three dead times in series were newly derived from the information obtained in these studies. An application of the derived formulae is briefly discussed.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.57.2-57.2
• /
• 2014

Protostellar jets and outflows are signatures of star formation and promising mechanisms for driving supersonic turbulence in molecular clouds. We quantify outflow-driven turbulence through three-dimensional numerical simulations using an isothermal version of the total variation diminishing code. We drive turbulence in real space using a simplified spherical outflow model, analyze the data through density probability distribution functions (PDFs), and investigate density and velocity power spectra. The real-space turbulence-driving method produces a negatively skewed density PDF possessing an enhanced tail on the low-density side. It deviates from the log-normal distributions typically obtained from Fourier-space turbulence driving at low densities, but can provide a good fit at high densities, particularly in terms of mass-weighted rather than volume-weighted density PDF. We find shallow density power-spectra of -1.2. It is attributed to spherical shocks of outflows themselves or shocks formed by the interaction of outflows. The total velocity power-spectrum is found to be -2.0, representative of the shock dominated Burger's turbulence model. Our density weighted velocity power spectrum is measured as -1.6, slightly less that the Kolmogorov scaling values found in previous works.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.7
• /
• pp.1265-1271
• /
• 2010

Power cable of an AC arc welder can surround a body of worker at the moment of welding. Applying the boundary element method, we calculated current densities induced in organs inside a worker to study the magnetic field reduction characteristics of shielding wear materials. We knew shielding wear with high permeability materials lowers current density more than high conductivity materials. We also found current density was lowest when high permeability materials were inside high conductivity materials in double layer shielding wear.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.7
• /
• pp.1237-1241
• /
• 2010

Supercapacitors as novel energy storage devices between conventional capacitors and batteries, with more specific capacitance and energy densities than conventional capacitors and more power densities than batteries are to be used in many fields. Supercapacitor is regarded as one of good alternatives for meeting the requirement of market with excellent power performance and high cyclability. This paper deals with the characteristics of charge and discharge behavior of supercapacitor module for developing 42V hybrid energy storage system with lead acid battery and supercapacitor in order to adopt to 42V power net for vehicle. An analysis performed in this paper indicates that supercapacitor storage system may be cost effective for high cycle applications.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.772-774
• /
• 2000

The objective of a cathodic protection system (CP) is to protect the buried metallic structure against the corrosion caused by chemical reaction between the buried structure and the surrounding medium, such as soil. This paper presents a boundary element application to determine the optimal impressed current densities in a cathodic protection system. The potential within the electrolyte is described by the Laplace's equation with nonlinear boundary conditions which are enforced based on experimentally determined electrochemical polarization curves. The optimal impressed current densities are determined in order to minimize the power supply for protection. The solution is obtained by using the conjugate gradient method in which the governing equations and the protecting conditions are taken into account by the penalty function method. Numerical example are presented to demonstrate the practical applicability of the proposed method.