• Journal of Power System Engineering
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• v.15 no.2
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• pp.13-18
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• 2011

This thesis is about the result of conducting a specific experiment for the development of noncontact vibration displacement sensor for measuring the spindle vibration that is used for conditional monitoring of machinery. One should be careful when using the eddy current type displacement sensor because the sensitivity of it is different according to the quality of the material. While the probe used for nondestructive inspection adopts the effect of transmitting the material by using the high frequency domain, the eddy current type displacement sensor uses the lower frequency of around 1MHz. Also, while the nondestructive probe uses the method of enhancing output by using the resonance zone, the vibration displacement sensor utilizes the stable zone by avoiding the resonance zone. Since the oscillator of the converter uses the "L" element as Probe, its characteristic changes with the variation of a relevant impedance. In other words, if the length of Probe's Cable gets extended (Impedance increase), the sensitivity declines accordingly. The effect of surrounding temperature was small, but the influence of the quality of Sensor Coil used was high. Moreover, following an experimental demonstration of the phenomenon where the sensitivity decreases as the frequency of the tested material increases from a frequency response test, the maximum frequency that could be measured was approximately 1KHz. It was noted that the degree of precision could be maintained by using the gap of the probe in the linear zone at the installation site.

• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.377-389
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• 2011

A higher quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The third generation index $C_{pmk}$ is more powerful than two useful indices $C_p$ and $C_{pk}$ that have been widely used in six sigma industries to assess process performance. In actual manufacturing industries, process capability analysis often entails characterizing or assessing processes or products based on more than one engineering specification or quality characteristic. Since these characteristics are related, it is a risky undertaking to represent the variation of even a univariate characteristic by a single index. Therefore, the desirability of using vector-valued process capability index(PCI) arises quite naturally. In this paper, we consider more powerful vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$ that consider the univariate process capability index $C_{pmk}$. First, we examine the process capability index $C_{pmk}$ and plug-in estimator $\hat{C}_{pmk}$. In addition, we derive its asymptotic distribution and variance-covariance matrix $V_{pmk}$ for the vector valued process capability index $C_{pmk}$. Under the assumption of bivariate normal distribution, we study asymptotic confidence regions of our vector-valued process capability index $C_{pmk}$ = ($C_{pmkx}$, $C_{pmky}$)$^t$.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.87-97
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• 1998

This study was performed to investigate the Natural mineral water quality at 47 sites in Chonnam area, samples were collected spring, summer, fall, winter for a seasonal variation in 1996. The results obtained were summarized as follows 1. The mean of F, pH, HCO$_3$, NO$_3$ -N were 0.19 mg/l, 6. 9, 34.99 mg/l, 1.40 mg/l and those of Na, K, Ca, Mg were 12.1 mg/l, 1.2 mg/l, 7.7 mg/l, 2.1 mg/l respectively. 2. The contents of F were reasonable at Multonggol as 1.35 mg/l and Yongbayui as 0.57 mg/l respectively, but there is no detected at Sidong and detected below 0.1 mg/l at Gubongsan, Hansansa area. 3. According to the geological effect, the content of F was showed higher in granite than in tuff, and index of pH was higher in tuff than in andesite, and content of HCO$_3$ was higher in andesite than in granite. 4. The K and O values were used as index of healthy and delicious water. As a result, thirtyfive sites(74.5%) was decided as healthy and delicious water. 5. The contents of NO$_3$-N were detected over 5 mg/l at Sukchonsa, Gajanggol, Yudalsan, Muchang, Kisan.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.789-798
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• 2016

Frequent algal blooms at major river systems in Korea have been serious social and environmental problems. Especially, the appearance of cyanobacteria with toxic materials is a threat to secure a safe drinking water. In order to model the behaviour of cyanobacteria cell number, an exclusive causality analysis using prewhitening technique was introduced to delineate effective parameters to predict the cell numbers of cyanobacteria in Seungchon Weir and Juksan Weir along Youngsan river system. Both input and output transfer function models were obtained to explain temporal variation of cyanobacteria cell number. A threshold behaviour of water temperature was implemented into the model development to consider winter characteristic of cyanobacteria. The implementation of water temperature threshold into the model structure improves the predictability in simulation. Even though the input output transfer model cannot completely explained all blooms of cyanobacteria, the simple structure of model provide a feasibility in application which can be important in practical aspect.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.6 s.360
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• pp.31-39
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• 2007

In this paper, a system for real-time or periodic measurement and analysis of RF parameters such as forward transmit power and pilot power in CDMA base station systems is proposed. Such RF characteristic parameter measurement can be prevented from system fault and used to achieve optimal service quality and maximum investment return through cell coverage expansion, subscriber capacity increase and so on. For forward power measurement, the local oscillator frequency for the detector is varied so that the transmit power for all channels can be measured. The channel power measurement can be used to analyze the variation in transmit power for changes in voice traffic. By comparing to forward $E_c/I_o$, the pilot channel power can be deducted, which can be used to determine uy degradation in transmit section modules such as the high dover amplifier. Since an accurate analysis of carefully measured data using the CDMA level detector must be made, the system is designed so that measurement errors due to changes in crest factor with modulation method can be overcome.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.179-185
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• 1984

These studies were carried out to evaluate the feasibility of using Alkali Digestibility Value (ADV) of soybean seeds as a selection criterion for cooking quality of soybean grain with rice, and to find out an optimal testing condition, varietal differences in ADV and the effect of cultural environment on the ADV, and its mode of inheritance. The ADV test was achieved succesfully by soaking the soybean grain for 24 hours in 25 to 30% KOH solution at 25 to $30^{\circ}C$. Varietal differences in the ADV were conspicuous, but cultural conditions affected the ADV little. All collected lines for cooking with rice showed high ADV and all the small grain cultivars introduced from abroad had low ADV, while recommended cultivars showed great variation in ADV. The characteristic of low ADV in soybean grains was controlled by single dominant gene.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.14-32
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• 2016

This study examines the morphological expression type and formative characteristics of women's shoes designs that integrate 3D printing technology. The results of the study are as follows. First, the morphological expression types of contemporary shoes that integrate 3D printing technology express a structural form created by repetition. Second, it expresses a dynamic form, which combines organic curves that create an external volume. Third, it expresses a surrealistic form centered on an object with the creation of a unique shape that utilizes objects easily experienced in local surroundings. Fourth, it expresses a hybrid form on a partial derivation. Each of the other system's components are fused to create another beauty that develops a new value in a colorful variation on the shape of 3D printing shoes. The first formative characteristic of women's shoes designs that integrate 3D printing technology is continuity. This creates an invisible form of a new space through repetitive unidirectional layers with a gradual expansion of a unitary seamless curves. Second, it is an exaggeration. This exaggeration elicits an enormous aesthetic quality by structuring the outward space in the difference of the volume formed based on the maximization of a specific part and the volume of a line's atypical movement. Third, it is a decoration. It displays the beauty of a decoration that evokes a unique artistic inspiration by partial unification or a practical representation of a specific form. This can also be seen as superimposing a 3D printing figure that has an outstanding shape onto part of the fashion shoes. Fourth, it concerns a geometrical characteristic that formulates a new structure with rationality in combining basic shapes such as circles, triangles and squares with lines, hexagons and interconnected geometrical forms to create a multi-dimensional space for shoes in a systematic and unidirectional pattern.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.2
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• pp.67-72
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• 2012

In recent days, the wire width of IC is narrowed and the degree of integration of IC is increased to obtain the higher capacity of the devices in electronic industry. And then the surface quality of FCCL(Flexible Copper Clad Laminate) became increasingly important. Surface defects on FCCL are bump, scratch, dent and so on. In particular, bumps cause low reliability of the products. Even though there are bumps on the surface, if leveling characteristic of plating solution is good, it does not develop significant bump. In this study, the leveling characteristics of additives are investigated. The objective of study is to improve the leveling characteristic and reduce the surface step through additives and plating conditions. The additives in the electrodeposition bath are critical to obtain flat surface and free of defects. In order to form flat copper surface, accelerator, suppressor and leveler are added to the stock solution. The reason for the addition of leveler is planarization surface and inhibition of the formation of micro-bump. Levelers (SO(Safranin O), MV(Methylene Violet), AB(Alcian Blue), JGB(Janus Green B), DB(Diazine Black) and PVP(Polyvinyl Pyrrolidone) are used in copper plating solution to enhance the morphology of electroplated copper. In this study, the nucleation and growth behavior of copper with variation of additives are studied. The leveling characteristics are analyzed on artificially fabricated Ni bumps.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.206-211
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• 2020

Tungsten alloys are used widely in general industrial fields, but they are difficult to cast, so products are manufactured using powder metallurgy. In this study, a mixed powder of tungsten, nickel, and iron homogenized using a ball mill was added to pure water as a solvent, and PVA as a binder was added to prepare a spray drying mixture. The mixed liquid was prepared using a spraying machine. A study was carried out to produce a granular powder that can reduce the variations between products during the molding and sintering process of the powder metallurgy method. A preliminary experiment was conducted to confirm the influence of the variables in the granulation process. Through the preliminary test results, this experiment was performed with the volume of solvent of the spray drying the mixture as an independent variable, and granular powder having a mean particle size similar to that of the existing mass-production conditions and an increased apparent density was prepared. In addition, a pilot test was conducted for the molding and sintering process. The improved granular powder reduced the characteristic variation (weight variation) of the mass-produced product.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.135-166
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• 1977

Some biochemical features of varietal variation in seed protein and their implications for soybean breeding for high protein were pursued employing 86 soybean varieties of Korea, Japan, and the U.S.A. origins. Also, studied comparatively was the temporal pattern of protein components accumulation during seed development characteristic to the high protein variety. Seed protein content of the 86 soybean varieties varied 34.4 to 50.6%. Non-existence of variety having high content of both protein and oil, or high protein content with average oil content as well as high negative correlation between the content of protein and oil (r=-0.73$^{**}$) indicate strongly a great difficulty to breed high protein variety while conserving oil content. The total content of essential amino acids varied 32.82 to 36.63% and the total content of sulfur-containing amino acids varied 2.09 to 2.73% as tested for 12 varieties differing protein content from 40.0 to 50.6%. The content of methionine was positively correlated with the content of glutamic acid, which was the major amino acid (18.5%) in seed protein of soybean. In particular, the varieties Bongeui and Saikai ＃20 had high protein content as well as high content of sulfur-containing amino acids. The content of lysine was negatively correlated with that of isoleucine, but positively correlated with protein content. The content of alanine, valine or leucine was correlated positively with oil content. The seed protein of soybean was built with 12 to 16 components depending on variety as revealed on disc acrylamide gel electrophoresis. The 86 varieties were classified into 11 groups of characteristic electrophoretic pattern. The protein component of Rm=0.14(b) showed the greatest varietal variation among the components in their relative contents, and negative correlation with the content of the other components, while the protein component of Rm=0.06(a) had a significant, positive correlation with protein content. There was sequential phases of rapid decrease, slow increase and stay in the protein content during seed development. Shorter period and lower rate of decrease followed by longer period and higher rate of increase in protein content during seed development was of characteristic to high protein variety together with earlier and continuous development at higher rate of the protein component a. Considering the extremely low methionine content of the protein component a, breeding for high protein content may result in lower quality of soybean protein.n.