• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.363-372
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• 2016

Two-stage sample designs are commonly used for household surveys in Korea using as clusters the enumeration districts (EDs). Since clustering decomposes the population variation into within- and between-cluster variations, the sample sizes allocated in stages can affect the overall precision. Alternative clusters are often considered due to diverse reasons such as the EDs' limitation in size, being out-of-date, and in-assessibility to their household lists. In addition, the EDs are currently under development by the Statistics Korea as an joint effort toward their transition from the traditional practice to the register census from 2015. We present an approach for evaluating the difference in the precision of the mean estimators of the sets of the cluster units in between a hierachical and nested form, where the design effect is used to reflect the effect of the clustering and the sample allocation. We also demonstrate our approach using the U.S. Census counts from the year 2000 for Anne Arundel County in Maryland. Our research shows that the within-cluster variance can be significantly different for survey variables and thus the choice of cluster units and the associated sample allocation scheme should reflect the corresponding variance decomposition due to clustering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.440-447
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• 2020

The purpose of this study is to identify the causation and variation among the various types of onion prices in the major production sites to predict these prices. The Granger causal relationship was tested on the basis of VECM by setting the onion price of the early, middle, and late species as individual variables. The analysis shows that the amount of onions produced in the prior term affects the price of onions for the later period, while garlic in the substitution relationship with onions also affects the prices of onions for the early and middle-variety. On the other hand, the price of the late-variety is affected by the price of the early-variety, and the price of the middle-variety is also affected by the price of the early-variety. If the price of onions on Jeju changes due to other factors, the prices of onions in Jeollanam-do and Gyeongsangnam-do provinces will be affected. Accordingly, when the production of late-variety increases or decreases in production under any factor and to promote stability of the prices of middle and late-variety through preemptive supply and demand measures when the prices of ultra-breed onions rise or fall due to any factor (Ed- I cannot understand this last sentence and cannot guess at the correct meaning. Please try to rewrite very simply).

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.76-84
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• 1986

All combinations of oxyfluorfen in 5 dosages and glyphosate in 4 dosages were used to assess the onto-drifting pattern of herbicide inactivation in three different type, such as check soil ($O^-M^-$), organic soil ($O^+M^-$), and micro-organism soil ($O^+M^+$). The plant used for bioassay was rape-hybrid. From the results, it was recognized that the herbicide inactivation is strongly achieved in order of $O^+M^+$ > $O^+M^-$ > $O^-M^-$ soil. Also, the inactivation of oxyfluorfen in soil tended to depend rather on soil microorganisms than organic matter, and to be promoted earlier by paraquat mixture than by that of glyphosate. Average 50 and 95% inactivated time (in days) of herbicides were getting shorten in order of $O^+M^+$, $O^+M^-$, $O^-M^-$, rather prolonged in mixture than in oxyfluorfen single treatment, and rather prolonged in high dose than in low dose, respectively.

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.436-442
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• 1988

The $^1H-nmr$ lineshapes of $H_2O$ in the solution containing $Al^{3+}$ ion have been measured as a function of temperature and $H^+$-ion concentration. Above [$H^+$] = 0.06, the lineshape were analyzed by the uncoupled two-site exchange model. From the proton exchange rate between hexaaquaaluminium ion and bulk water as a function of H-ion concentration. These kinetic data could be fitted to a following linear rate law; that is; 1/${\tau}$ = k$_1$/12 + $k_2$[$H^+$]/6. The following proton exchange parameters were obtained; $k_1^{298}$ = 38.5s$^{-1}$ ${\{Delta}H_1^{\neq}$ = $42.9kJ mole^{-1}$ ${\{Delta}S_1^{\neq}$ = -48.6J $mole^{-1}K^{-1}$ $k_2^{298}$ = $172s^{-1}mole^{-1}$ ${\{Delta}H_2^{\neq}$ = 27.8kJ $mole^{-1}$ ${\{Delta}S_2^{\neq}$ = -90.3J $mole^{-1}K^{-1}$ These activation parameters are indicating an associative interchange, Ia, mechanism for the acid-hydrolysis of hexaaquaaluminium ion and the proton exchange between the hydration spheres of $Al^{3+}$ and $H^+$.

• Journal of the Economic Geographical Society of Korea
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• v.4 no.2
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• pp.57-77
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• 2001

The Honam region has been recognized as one of the most lagging regions in Korea. Drawing upon some decompositions oi Gross Regional Domestic Product(GRDP) per head and labor productivity, the overall trend of inequalities in Korea has been revealed and the trajectory of the Honam region's economic change has been identified by examining how the region's economic performance changed relative to that of Korea in the 1990s. There are some findings. First of all, Korea is characterized by strong divergence in the development of its region economies, in terms o\ulcorner per capita GRDP, which relies upon productivity differentials rather than differences in employment rates. Second, the Honam region has displayed poor economic performances in terms of GRDP per head except for Jeonnam. Third, the dramatic fall in cumulative population growth relative to the national average has been an important factor in the Jeonnam's overwhelming economic performance measured by per capita GRDP. Fourth, the decline in the relative productivity of the Honam region is mostly explained by falling relative regional productivity growth in construction, transport and manufacturing, although it should be noted that the latter sector has made positive contribution to raising relative regional productivity of Jeonnam. Fifth, overall the shift in employment to service sector, especially to social, personal, public, health, education, other services other than distribution, hotels, catering has tended to support relative regional productivities, along with the positive contribution being made oi agriculture, forestry and fishing to relative regional productivity growth in the Honam region.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.555-575
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• 2019

Though housing market varies spatially, housing policy is limited in reflecting detailed regional differentiation. This study looked at the differences in Seoul Gu Districts' response to housing policy for the efficient implementation of housing policies in the future. Housing policy index was established by each Gu-districts' according to investigated housing policies from 2003 to 2018, weighted in two categories(financial/urban planning) and the status of designated areas. The VECM model was established to analyze the impact of the housing policy on the housing market. According to the analysis, although housing policies were established in response to market prices change, the impact of policies on prices was lower than the impact of vice versa. The housing policy's impact to the housing market is limited in some areas in northeastern Seoul. These results show that there are differences in the responses to housing policy in Seoul districts', and therefore detailed consideration of the differences in the regional aspects of housing policy is needed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.590-597
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• 1985

A recursive geometric adaptive control method to compensate for machining straightness error in the finished surface due to tool deflection and guideway error generated by end milling process is developed. The relationship between the tool deflection and the feedrate is modeled by a modified Taylor's tool life equation. Without a priori knowledge on the variations off cutting parameters, time varying parameters are then estimated by an exponentially windowed recursive least squares method with only post-process measurements of the straightness error. The location error is controlled by shifting the milling bed in the direction perpendicular to the finished surface and adding a certain amount of feedrate with respect to the tool deflection model before cutting. The waviness error is compensated by adjusting the feedrate during machining. Experimental results show that location error is controlled within a range of fixturing error of the bed on the guideway and that about 60% reduction in the waviness error can be achieved within a few steps of parameter adaption under wide operating ranges of cutting conditions even if the parameters do not converge to fixed values.

• Korean Journal of Food Science and Technology
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• v.13 no.3
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• pp.188-193
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• 1981

Thermal degradation of pantothenic acid in potassium biphthalate buffer and in food samples such as rice, mushroom and beef was studied as functions of temperature and pH. Thermal degradation of pantothenic acid in buffer and food systems followed first order reaction at temperature between $60{\sim}104^{\circ}C$. Activation energy calculated from the Arrhenius equation ranged from 15,700 cal/mole 17,300 cal/mole for both systems. D values at $120^{\circ}C$ were approximately 18 hours for food samples and 15.4 hours at pH 5.65 for buffer sample. Z values of food samples were about $37^{\circ}C$, which were similar to those of buffer sample. The decomposition rate constant of pantothenic acid in buffer sample decreased when the pH increased from 4.0 to 6.46, but activation energy increased. In the range of $pH\;6.46{\sim}8.0$, decomposition rate constant increased but activation energy decreased as pH increased. The kinetic model of pantothenic acid decomposition in buffer system was proposed on the basis of empirical relationship.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.553-558
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• 2003

The crystal structure of $[n-Bu_4N]_2[Mo_6O_{19}]$(TBAM) (n-Bu4N=tetrabutylammonium) has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters ${\alpha}$=16.314(5), b=17.288(5), c=17.776(4)${\AA}$ ${\beta}$=101.47(3), and Z=4. In $[Mo_6O{19}]^{2-}$ anion, Mo atoms occupy six vertices of octahedron and each Mo atom is coordinated by six oxygen atoms to adopt distorted octahedral coordination geometry. The average bond distance of Mo-Ot (terminal), Mo-Ob (bridged) and Mo-Oc (central) are 1.680 ${\AA}$, 1.931 ${\AA}$ and 2.325 ${\AA}$ respectively. In $[n-Bu_4N]^+$ cation, the N atom possesses a slightly distorted tetrahedral geometry. There are some potential extensive C-H ${\cdots}$ O hydrogen bonds in the lattice, by which connecte molecules and stabilize the crystal structure. Thermogravimetric analysis suggests that thermal decomposition of the title compound includes two transitions and it loses weight at 356.0 and 803.5 $^{\circ}$, respectively, and the residue presumable be $Mo_2O_2$. Accordingly, the title compound has high thermal stability.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.1-6
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• 2001

Emulsion products with water soluble protein were exposed under light at $5^{\circ}C$ for 8 days. Peroxide value (POV) was increased significantly at the bigining of storage and 2-thiobarbituric acid (TBA) value also increased until 4 days of storage with increase of the production of carbonyl compounds, suggesting that the condition was reacted different from that of the lipid autoxidation. The reaction was similar to the flavor reversion that usually produced from the bigining of soybean oil oxidation. The reason might be the meat pigment, myoglobin, oxidation and it would be due to the singlet oxygen rather than superoxide anion. When the light was excluded general pattern was similar but the production of oxidation products were smaller than that when the sample was exposed under light. The effect of the singlet oxygen was also smaller which meant that the singlet oxygen produced during emulsion process may affect on the flavor reversion at the bigining of storage. The POV of the emulsion without water soluble protein increase gradually by storage and the results indicated that the degradation rate of the peroxides were lower than the sample with water soluble protein. Especially after 4 days of storage, production of carbonyl compounds were decreased. During storage it would be possible to produce the singlet oxygen and the sensitizer from the plants that can be produced during decoloration of soybean oil may be responsible for it. When the light was excluded the production of oxidation products were reduced at the begining of storage and the effect of quencher also was not detected. Therefore the results indicated that the light can accelerate the lipid oxidation.