• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.259-265
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• 2005

A two-degree-of-freedom out-of-plane model with contact stiffness is presented to describe dynamical interaction between the pad and disc of a disc brake system. It is assumed that the out-of-plane motion of the system depends on the friction force acting along the in-plane direction. Dynamic friction coefficient is modelled as a function of both in-plane relative velocity and out-of-plane normal force. When the friction coefficient depends only on the relative velocity, the contact stiffness has the role of negative stiffness. The results of stability analysis show that the stiffness of both pad and disc is equally important. Complex eigen value analysis is conducted for the case that the friction coefficient is also dependent on the normal force. The results further verify the importance of the stiffness. It has also been found that increasing the gradient of friction coefficient with respect to the normal force makes the system more unstable.

• Agricultural and Biosystems Engineering
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• v.6 no.2
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• pp.59-64
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• 2005

In the study, the cone index, the cohesion and the internal resistant angle of soil were measured before and after tillage in order to suggest relative improvement in soil properties. The tillage methods tested in the study were five combinations of plow and rotary tillage operation and the experiments were performed on five selected test fields. The maximum tillage depth was 20 cm under the ground. The CIs for all the tillage operations were improved in comparison with those before tillage. The best combination of tillage operations for improving the CIs of soil was one plow operation followed by one rotary. After applying the tillage operations, the internal resistance angle reduced by 7-8 degree and the cohesion decreased up to about $1N/cm^2$ in comparison with those before tillage. We concluded that the cone index, the cohesion and the internal resistant angle of soil could be used as measures for representing the relative degree of tillage for a specific tillage operation. In addition, the study was useful as a basic research tool for developing an decision making system that determines an optimal tillage method with soil properties.

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.81-90
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• 1992

The effect of acid treatment of cellulose on the substitution charateristics of carboxymethylation was studied in this paper. Five samples of hydrocellulose(HC), all prepared from ${\alpha}$-cellulose by hydrolysis with five reaction times and determined on average molecular weight and polydispersity, were carboxymethylated to carboxymethyl cellulose (CMC). The CMCs from HCs were examined upon degree of substitution(DS), distribution of carboxymethyl groups in anhydroglucose units of the cellulose, and unsubstituted anhydroglucose(USAG) content. The DS of CMCs increased with increasing the hydrolysis time except CMC from HC at 1 hour hydrolysis time. In carboxymethylation the availability of hydroxyl groups on anhydroglucose units in HCs was the highest on OH(2), and the relative availability of OH(6) increased with the increasing of the hydrolysis time. The USAG contents were more deviated than that calculated based on Spurlin's model, and had a strong tendency of decreasing with increasing the hydrolysis time. The reactivity of HC was lower than that of ${\alpha}$-cellulose and the relative availability of OH(6) in HC increased with the hydrolysis time.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.5
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• pp.588-599
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• 2003

The convenience of TV home shopping is known to provoke compulsive buying, which is chronic and repetitive purchasing behavior that comes about as a response to negative events or feelings. The purpose of this study was to identify whether there is a difference in the degree of compulsive buying between the purchasers of fashion goods and the purchasers of non-fashion goods on TV home shopping shows and the determinants of compulsive buying and their relative importance. Utilizing the convenient sampling method, the sample of the study was composed of women aged over 20 living in the Seoul metropolitan area. Out of 380 distributed questionnaires, 270 useful questionnaires were returned. The data were analyzed using t-test, Pearson correlation, and multiple regression. The results indicated that TV home shoppers who purchased fashion goods showed higher degree of compulsive buying than those who purchased non-fashion goods and the determinants of compulsive buying are sample＇s age, mean age of the sample＇s children, credit usage, expenditure on fashion goods, frequency of purchase of fashion goods on TV home shopping shows, and promotional tools used by TV home shopping retailers. Regarding the relative importance of the determinants, credit usage was the most influential factor followed by expenditure on fashion goods and the length of exposure to TV home shopping shows.

• Earthquakes and Structures
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• v.13 no.4
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• pp.377-386
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• 2017

Earthquake-induced pounding damages to building structures were repeatedly observed in many previous major earthquakes. Extensive researches have been carried out in this field. Previous studies mainly focused on the regular shaped buildings and each building was normally simplified as a single-degree-of-freedom (SDOF) system or a multi-degree-of-freedom (MDOF) system by assuming the masses of the building lumped at the floor levels. The researches on the pounding responses between irregular asymmetric buildings are rare. For the asymmetric buildings subjected to earthquake loading, torsional vibration modes of the structures are excited, which in turn may significantly change the structural responses. Moreover, contact element was normally used to consider the pounding phenomenon in previous studies, which may result in inaccurate estimations of the structural responses since this method is based on the point-to-point pounding assumption with the predetermined pounding locations. In reality, poundings may take place between any locations. In other words, the pounding locations cannot be predefined. To more realistically consider the arbitrary poundings between asymmetric structures, detailed three-dimensional (3D) finite element models (FEM) and arbitrary pounding algorithm are necessary. This paper carries out numerical simulations on the pounding responses between a symmetric rectangular-shaped building and an asymmetric L-shaped building by using the explicit finite element code LS-DYNA. The detailed 3D FEMs are developed and arbitrary 3D pounding locations between these two buildings under bi-directional earthquake ground motions are investigated. Special attention is paid to the relative locations of two adjacent buildings. The influences of the left-and-right, fore-and-aft relative locations and separation gap between the two buildings on the pounding responses are systematically investigated.

• Review of Culture and Economy
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• v.19 no.2
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• pp.171-193
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• 2016

China's advertising industry has rapidly increased owing to economic growth and big market size. This paper covers the localization and relative efficiency in the Chinese advertising industry. To analyze localization level and efficiency of advertising industry, this paper uses Location Quotient(LQ) and Data Envelopment Analysis (DEA) respectively. According to the results, the first finding shows that the higher regional development level have the relative efficiencies, the higher regional development level also have regional specialization degree. The second finding indicates that Chinese advertising industries are multipolalized region by region. The last finding reveals that advertising industry of middle and west regions has long term development potentiality owing to high specialization degree with low relative efficiencies.

• Journal of Korean Academy of Nursing
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• v.29 no.5
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• pp.1072-1086
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• 1999

This study has been attempted using the Q methodology to clarify leader type of nurse managers that head nurses and general nurses recognize, and to clarify its relative relation. Sixty-three statements were extracted through interviews with general and professional people interested in the subject of nurse leaders to extract the Q population. A total of 314 Q population was formed added with 251 questions extracted from related documents. Final 32 Q samples were selected by reorganization of 314 Q population after reexamining statements through inquiry of 1 professor of the nurse department, 2 students in course of nurse science masters degree and 2 students in course of doctoral degree. The P sample selection standard of this study were 25 nurses and 30 head nurses. Examination subjects themselves filled out 32 statements classified in a measure of 9 points from agreeable items to disagreeable items. Principal component factors were analyzed using the QUANL pc program after grading the contents of the P sample. Nurses recognizing subjective structure for leader behaviors of nurse manager were analyzed to be 3 factors: vision presentation type, self-capability consideration type, relationship consideration type, and head nurses recognizing subjective structure were analyzed to be 2 types: task pursuit leader type, and concord pursuit type. Nursing manager's leader behavior, expected by staff nurse are more complex and higher level which may combined with task pursuit leader type in concord pursuit leader of head nurse. Also according to Horsey and Blanchard theory(1977), the effectiveness of leadership becomes to be larger as the accordance rate between the behaviors of nurse leaders and followers reaction increase Two suggestions have been made based on the conclusion. 1. Studies on creating strategies in relation to development, management, selection of nurse leaders should be made based on this study. 2. There is a need for relative study of production and degree of similarity of leadership types based on this study.

• Korean Journal of Community Nutrition
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• v.10 no.3
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• pp.331-340
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• 2005

The purpose of this study was to provide basic data to improve college food service satisfaction with sanitary, environment and service by comparing 2 contract-managed and 2 self-operated college food services in Daejeon and Chungnam area. According to the results, sanitation and environment satisfaction degrees of contract-managed college food services were higher than those of self-operated food services. The satisfaction degrees with service were also higher in contract-managed food services than self-operated food services except the category of quick food delivery. In all categories comprising the food service satisfaction, the satisfaction degrees were lower in female students than in male students. There were more negative self-perceived clinical symptoms in female students than male students. The higher the negative self-perceived clinical symptoms scores were, the lower the satisfaction degrees with food service were, which suggests that かe health state of students was one of the factors that influenced college food service satisfaction. There was no difference between contract-managed and self-operated food services in terms of satisfaction with overall food taste and overall satisfaction degree. The average satisfaction degree for the contractmanaged food services in terms of price relative to food quality was lower than that for self-operated food services. According to stepwise multiple regression analysis, 'overall food taste', 'price relative to quality', 'kindness of employees', 'coping with proposed opinions' and 'quicknless of food delivery' in decreasing order, were the most relatively important attributes for overall satisfaction. There should be further studies on important management factors to improve satisfaction with sanitary, environment and service by self-operated college food service.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.59-65
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• 2007

The study was carried out to investigate water activity, physicochemical properties and color degree of burley tobacco stored in shelf with different moisture content for 56 days. The study was consist of two experimental designs, that is, moisture content in burley tobacco was kept to 13 to 15 %, 17 to 19 %, and 21 to 23 % under ambient temperature of $20^{\circ}C$ with relative humidity of 24 %, and another group of in burley tobacco was only kept in ambient temperature of $3^{\circ}C$ with relative humidity of 50 % for 56 days with same water content of former treatment. Normal leaves were kept for 56 days under 21 to 23% of moisture content with increased water activity and TSNA(tobacco-specific nitrosamine content. It was considered that favorable leaves conditions are due to favorable microbial growth resulting in increased TSNA content. The total nitrogen content has not changed in two experimental groups for 56 days, otherwise the nitrate form nitrogen and total alkaloid contents were only increased by 21 to 23 % of water content. Degree of pH change was slightly decreased in both storage and water treatment. It was more decreased in 21 to 23% of moisture content than that of other moisture content. In stored leaf tobacco, higher moisture content caused lower brightness, yellow degree, and carbonization quotient.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.31-39
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• 2003

The enzymatic isolation of residual lignins obtained from spruce and beech pulps (obtained by sulfite, kraft, ASAM and soda/AQ/MeOH pulping processes) and their characterization was described in previous publications. Here, the residual lignins have been submitted to potassium permanganate oxidation (KMnO₄ degradation), and 9 aromatic carboxylic acids (3 of them are dimeric) were identified after methylation with diazomethane by GC/MS. The analytical challenge during qantification by the internal standard methods was the partly high protein content of the samples, which resulted in elevated anisic acid yields in the degradation mixture of sulfite residual lignins. The results are compared with the KMnO₄ degradation of the corresponding MWLs and discussed in terms of S/G ratios and degrees of condensation. The latter was calculated as a quotient between the aromatic carboxylic acids derived from condensed and non-condensed lignin structures. Typical degradation patterns for the various processes have been observed. Among other parameter, the relative compositions between iso-hemipinic acid (which is for condensation in pos. 5 of the aromatic ring) and meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (both are for condensation in pos. 6 of the aromatic ring) was found to be process specific. Kraft and soda/AQ/MeOH residual lignins yielded higher amounts of iso-hemipinic acid. In contrast, the relative yields of meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (the latter in beech lignins) are higher in sulfite and particularly in ASAM residual lignin. In case of beech residual lignins the amount of acids originated from non-condensed syringyl type lignin units was surprisingly high. The condensation degree of residual lignins was shown to be generally higher than that of MWLs. This was especially true for the G units. ASAM residual lignin exhibited very high S/G ratios and degrees of polymerization. Causality between condensation degree and total yield of degradation products was demonstrated.