• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.21-32
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• 2007

The households to be surveyed are usually huge number at the level of a city or metropolitan survey, not to mention a nationwide travel survey. Therefore, household travel surveys to figure out true origin-destination (O/D) trip patterns (population O/D) are conducted through a sampling method rather than by surveying all of the population in the system. Therefore, the population O/D pattern can only be estimated by expanding the sampled O/D patterns to the population. It is very difficult to avoid the errors involved in the process of sampling, surveying and expanding O/D data. In order to minimize such errors while estimating the true O/D patterns of the population, the validation and adjustment process should employed by doing a comparison between the expanded sample O/D data and observed link traffic volumes. This study suggests a method of validation and adjustment of the expanded sample O/D data by comparing observed link volumes at several screenlines. The study also suggests a practical technique to modify O/D pairs which are excluded in the screenline validation process by comparing observed traffic volume with the results of traffic assignment analysis. An empirical study was also conducted as an example applying the suggested methods of validation and adjustment with Korea's nationwide O/D data and highway network.

• The Korean Journal of Nuclear Medicine
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• v.17 no.1
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• pp.11-15
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• 1983

Left ventricular volume would be useful in the diagnosis and treatment of patients with various heart diseases. So we measured left ventricular volume index using gated blood pool nuclear cardiac angiography which was easy to perform, non-invasive, and capable of repetitive studies. These left ventricular volume indices were compared with left ventricular volumes by quantitative cardiac cine-angiography and the results were as follows, 1. The correlation coefficient between left ventricular volume indices and left ventricular volumes was 0.829 (p<0.001). 2. The correlation coefficient between left ventricular volume indices and absolute left ventricular volumes which were obtained by measurement of cardiac output of patients. 3. There were good correlation in intraobserver and interobserver analysis.

• Journal of the Korean Magnetics Society
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• v.26 no.6
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• pp.196-200
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• 2016

In this study the mechanisms of magnetization reversal and magnetic interaction effects on activation volumes for Sr-ferrite with different particle sizes are investigated. The activation volumes of C2 sample are larger than those of C3 sample in the range of low magnetic fields. But the fields above the coercivity of sample C2, the activation volumes of both samples are decreased linearly with increasing the applied magnetic field. These phenomena can be explained by the strengths of two critical fields representing the reverse domain nucleation field and the domain wall pinning field as well as the strength of dipolar interaction.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.232-236
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• 2000

CoSm thin films with a Cr underlayer have received continuous attention as a potential material for a high density longitudinal magnetic recording media. In this study the Ax gas sputtering pressure effects on the magnetic properties of CoSm thin films, which were fabricated by using a dc magnetron sputtering machine, were investigated. The magnetic switching volume is especially important parameter to understand the thermal stability of the written information, magnetization reversal process and media noise. Therefore, in this paper the effects of sputtering pressure on the magnetic switching volume of CoSm thin films grown on Cr underlayer with the same sputtering conditions was studied. As the Ar sputtering pressure during sputtering of the CoSm magnetic layer increases from 5 to 30 mTorr, the measured switching volumes decreased from 9.0 to 5.2$\times$10$^{-18}$ cm$^3$. The calculated diameter of switching unit from V＊ was less than 22 nm, which satisfies the Sharrock's requirement on the thermal stability of the high density longitudinal magnetic recording media.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.37-44
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• 1987

The rates of solvolysis of $cis-[Co(en)_2Cl_2]^+$ complex have been investigated using spectrophotometric method at various pressures up to 1500 bar in several binary-aqueous mixtures(water-methyl alcohol, water-acetone, water-isopropyl alcohol and water-ethylene glycol). The activation volumes obtained from the pressure effect on rate constants were 1.13∼4.44 cm3mole-1 for methyl alcohol, 1.13∼3.59$cm^3mole^{-1}$ for acetone, 0.82∼3.44$cm^3mole^{-1}$ for isopropyl alcohol and 1.13∼2.68cm3mole-1 for ethylene glycol. In case of water-methyl alcohol, in addition to, the rates of solvolysis of this complex were determined in the presence of Fe(Ⅱ) ion and the activation volumes were -0.56∼1.59cm3mole$^{-1}$. The rates of solvolysis of this complex were analyzed by comparing with the results obtained from activation volumes and free energy cycle.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.31-36
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• 1987

We examined eluting behaviors for cationic complexes with the eluting cations. Retention volumes of hydrophilic complexes when eluted by the high concentration of aqueous KCl, NaCl and $NH_4Cl solutions, have been increased in the order NH_4^+ > Na^+ > K^+$, but in the low concentration, retention volumes of hydrophilic complexes bave been increased in the order $Na^+ > NH4^+ > K^+$. On the order hand, retention volumes of hydrophobic complexes when eluted by aqueous KCl, NaCl and $NH_4Cl solutions, have been increased in the order NH_4^+ > Na^+ > K^+$ in the whole concentration range. And we examined eluting behaviors for cationic complexes with the eluting anions. Hydrophilic complexes were associated more strongly with chloride ion among halide ions. However, hydrophobic complexes were associated more strongly with iodide ion. Sulfate ion, a highly hydrated anion, was associated more strongly with hydrophilic complexes than with hydrophobic complexes.

• Resources Recycling
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• v.23 no.3
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• pp.51-60
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• 2014

In this study, the domestic supply & demand of the raw materials of 35 rare metals was analyzed categorized as four types - ores, metals, compounds and scraps. Foreign trade volumes of the raw materials of rare metals have been steadily increased, furthermore, recently trade growth rate highly exceeds GDP. The raw materials of rare metals - silicon, nickel, molybdenum, manganese, etc. - for steel industry were the most big part of the raw materials of rare metals trade, while the raw materials of rare metals for electronics industry were imported relatively small volumes less than $100 million. However systematic supply & demand management on the raw materials of rare metals for electronics industry is needed since recently growth rate per year has been remarkably high over 20%. Import volumes were about three times bigger than export scale, and most of the raw materials of rare metals were traded as a metal form.

• Journal of the Ergonomics Society of Korea
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• v.7 no.1
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• pp.21-30
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• 1988

The investigation of the surface areas, volumes and sizes (circumference, length, breadth) changes has been performed on women during menstruation, non-menstruation, pregnancy and post-pregnancy periods. (1) During menstruation and non-menstruation periods: The subjects were 30 healthy women from 19 to 24 years of age. The changes of lower leg areas were measured using the paper replacement method, showing an increase of 0.71% in surface during the menstruation period. The changes of lower 1g volumes were measured by the water replacement method, showing an increase of 1,74% in volume during the menstruation period. The correlation between the surface area changes and the volume changes was of r=0.45. The greatest change among the four parts of the leg was found at the ankle in both experiments. We measured also the foot length(1), the ball of foot girth(2), the foot breadth(3), the instep height (4), the instep girth(5), the ankle girth(6), the calf circumference(7) and we found the greatest changes in(4)=3,92% in(5)=0.79% and in (7) =0.84%. (2) During pregnancy and post-pregnancy periods: The subjects were 3 women, two pregnants(both from the 24th to the 36th week of pregnancy during the experiment) and one post-pregnant(from the second week to the eighth week during the expriment). For the first two subjects, we measured only the last 6 items of the preceding experiments(foot length(1),ball of foot girth(2), (3), (5), (6), (7)), Showing the greatest changes in the instep girth(5) and the calf circumference(7). In the case of the post-pregnant subject, these two items (5) and(7) decreased sharply during the second, third and fourth week and remain approximately the same afterwards.

• Korean Journal of Biological Psychiatry
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• v.25 no.2
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• pp.38-43
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• 2018

Objectives Dopamine dysregulation has been regarded as one of the core pathologies in patients with schizophrenia. Since dopamine synthesis capacity has found to be inconsistent in patients with schizophrenia, current classification of patients based on clinical symptoms cannot reflect the neurochemical heterogeneity of the disease. Here we performed new subtyping of patients with first-episode psychosis (FEP) through biotype-based cluster analysis. We specifically suggested basal ganglia structural changes as a biotype, which deeply involves in the dopaminergic circuit. Methods Forty FEP and 40 demographically matched healthy participants underwent 3T T1 MRI. Whole brain parcellation was conducted, and volumes of total 6 regions of basal ganglia have been extracted as features for cluster analysis. We used K-means clustering, and external validation was conducted with Positive and Negative Syndrome Scale (PANSS). Results K-means clustering divided 40 FEP subjects into 2 clusters. Cluster 1 (n = 25) showed substantial volume decrease in 4 regions of basal ganglia compared to Cluster 2 (n = 15). Cluster 1 showed higher positive scales of PANSS compared with Cluster 2 (F = 2.333, p = 0.025). Compared to healthy controls, Cluster 1 showed smaller volumes in 4 regions, whereas Cluster 2 showed larger volumes in 3 regions. Conclusions Two subgroups have been found by cluster analysis, which showed a distinct difference in volume patterns of basal ganglia structures and positive symptom severity. The result possibly reflects the neurobiological heterogeneity of schizophrenia. Thus, the current study supports the importance of paradigm shift toward biotype-based diagnosis, instead of phenotype, for future precision psychiatry.

• Journal of Korea Port Economic Association
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• v.25 no.1
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• pp.1-14
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• 2009

This study predicted Port trade volume by considering Korea's export to China and import Com China separately using ARIMA model (Multiplicative Seasonal ARIMA Model). We predicted monthly Port trade volumes for 27 months from October 2008 to December 2010 using monthly data from September 2008 to January 2001 using monthly data. As a result of prediction, we found that the export volume decreased in January, February, August and September while the import volume decreased in February, March, August and September. As the decrease period was clearly differentiated, it was possible to predict export and import volumes. Therefore, it is believed that the results of this study will generate useful basic data for policy makers or those working for export and import enterprises when they set up policies and management plans. And to improve competitive power of Port trade, this study suggests privatization of Port, improvement of information capability, improvement of competitive power of Port management companies, support for Port distribution companies, plans for active encouragement of transshipment, and management of added value creation policy.