• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.32-44
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• 1987

This study was carried out to analyze and furecast the domestic demand for plywood in Korea by regression models with time-series data for 16 years(1970-85). The results obtained were summarized as follows. 1. To analyze domestic demand for plywood, GNP, PWI and CWI were used as independant variables. The domestic demand equation was computed as follows: $^{in}DDP$=0.65186+1.29412 $^{in}GNP$-0.28385 $^{in}PWI$-1.05011 $^{in}CWI$ Where DDP : Domestic demand for plywood(1000 S/F) GNP: Gross national product (Billion won) PWI : Real wholesale price index of plywood CWI: Real wholesale price index of construction materials. 2. Among independant variables reflecting on the production activity of plywood industry, GNP was the most decisive in forecasting the domestic demand for plywood. 3. The significance can be recognized highly because the decision coefficient of the forecasting model which is obtained by using time series data is 0.9. 4. According to the estimated regression coefficients for GNP, PWI and CWI, GNP shows positive relation while PWI and CWI show negative relation. 5. An annual average increase rate of demand for plywood was 9.4 percent during expect period. Therefore, it was decreased slightly than that of 10.2 percent during sample period.

• The Journal of Society for e-Business Studies
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• v.11 no.2
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• pp.49-69
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• 2006

The virtual community has been recognized as an effective marketing tool and has been an important motive of using internet to Internet users, but very few attempts have been done for the development of virtual community success. Although many studies have been made on influencing factors of virtual community success, the comprehensive studies have never been done so far. Therefore, this study focused on developing the comprehensive model and verifying empirically. This study proposed five influencing factors(Virtual Community Operational factor, Characteristics of Users, Usefulness, Trust, Commitment) that affect virtual community success and three success factors(Sense of Virtual Community, Loyalty, Purchasing Intention) by carrying out literature review extensively and suggesting the relationship among factors. The relationship among factors were empirically validated by structural equation modeling. The data used in this study were collected from 292 users of the existing virtual communities. As the result of statistical analysis. It was found that Virtual Community Operational Factor and Characteristics of Users statistically significantly influenced Virtual Community Success. Also, it was shown that the intervening effects of Usefulness, Trust and Commitment were statistically significant, but that the relationship between commitment and Loyalty was not statistically significant. Finally, it turned out that the causality among success variables of Virtual Community was supported, but that sense of Virtual Community was required to be measured by new measurements.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.72-79
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• 1997

Adsorption, leaching, and retention of the Flupyrazofos(KH-502), a new active ingredient for insecticide, in the soils under laborarory and field conditions were investigated to provide the basic data for the safety use and to assess a secondary impact of this insecticide on soil and water environments. A significant power function relation was found between the adsorbed KH-502 and time, representing that 45% of the added KH-502 was adsorbed within 30 min. but a quasiequilibrium was reached after 6 to 12 hr with a slower adsorption. Adsorption phenomena followed th first-order kinetics and time required for 50% adsorption was 5.8 hr. The equilibrium adsorption isotherm was explained by the Freundlich equation and was classified as S-type. The amounts of KH-502 leached through the soil column (C) as compared to initial conc. ($C_0$) were very low and these relative concentrations ($C/C_0$) were 0.073 and 0.017 in SL and CL soils, respectively. The residual conc. of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 in the surface soil was comparatively low and decreased with time. Half-lives of KH-502 under the field conditions were estimated to be 20 and 18 days in the SL and CL soils, respectively. The KH-502 cone, transported to the subsurface soils was extremely low. These results demonstrate that KH-502 has a low pollution risk potential to the surrounding environment as far as it is used following the recommended guideline.

• Food Science and Preservation
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• v.15 no.6
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• pp.832-839
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• 2008

The stock that is the first step for preparation of soups and purees links to the taste of food. Many types of vegetable have been used in stocks, but this study focused on stocks prepared with sweet pumpkin. The stock preparation conditions including the weight of sweet pumpkin, the water volume, and the boiling time at $97^{\circ}C$ were optimized by response surface methodology. The quality characteristics of the resulting stock were investigated. The color, flavor, taste and overall acceptability were dependent parameters. A model equation was proposed with regard to the sweet pumpkin weight, water volume, and boiling time at $97^{\circ}C$. A sweet pumpkin weight of 357.9 to 403.0 g, a water volume of 689.8 to 768.5 mL, and a boiling time of 9.9 to 10.3 min at $97^{\circ}C$ were found to be the optimal stock preparation conditions. The quality characteristics of the sweet pumpkin stock prepared under the optimized conditions were pH 6.64, total acidity 0.18%, soluble solids $2.39\;^{\circ}Brix$, color value (L, 99.07 a, -2.43 b, 11.82), total polyphenol 280.75 mg/L, and electron donating ability 21.32%.

• Journal of the Korea Concrete Institute
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• v.24 no.1
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• pp.25-35
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• 2012

For a member subjected to direct shear forces, forces are transferred across interface concrete area and resisted by shear transfer capacity. Shear-friction equations in recent concrete structural design provisions are derived from experimental test results where shear-friction capacity is defined as a function of steel reinforcement area contained in the interface. This empirical equation gave too conservative values for concrete members with large amounts of reinforcement. This paper presents a method to evaluate shear transfer strengths and to define ultimate conditions which result in crushing of concrete struts after yielding of longitudinal reinforcement perpendicular to the interface concrete. This method is based on the bi-axial stress field theory where different constitutive laws are applied in various means to gain accurate shear strengths by considering softening effects of concrete struts based on the modified compression-field theory and the softened truss model. The validity of the proposed method is examined by applying to some selected test specimens in literatures and results are compared with recent design code provisions. A general agreement is observed between predicted and measured values at ultimate loading stages in initially uncracked normal-strength concrete test.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.583-592
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• 2008

Recently, the effects of high temperature on compressive strength, elastic modulus and strain at peak stress of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 to 700 on the material mechanical properties of high strength concrete of 40, 60, 80 MPa grade. In this study, the types of test were the stressed test and stressed residual test that the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating and when target temperature is reached, the specimens are loaded to failure. And another specimens are loaded to failure after 24 hour cooling time. Tests were conducted at various temperatures ($20{\sim}700^{\circ}C$) for concretes made with W/B ratios 46%, 32% and 25%. Test results showed that the relative values of compressive strength and elastic modulus decreased with increasing compressive strength grade of specimen and the axial strain at peak stress were influenced by the load before heating. Thermal strain of concrete at high temperature was affected by the preload level as well as the compressive strength. Finally, model equation for compressive strength and elastic modulus of heated high strength concrete proposed by result of this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.267-277
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• 2018

This study examined the job satisfaction and its association with violence experience, job stress, and burn-out. A total of 1,240 119 rescue workers who worked in 14 fire stations across the country were surveyed. The survey was conducted by self-administered questionnaires from 1 March, to 30 April, 2016. As a result, the score of job satisfaction according to violence experience, job stress, and burn-out were significantly lower in the group with higher scores of violence experience, job stress, and burn-out. Regarding the correlation of job satisfaction with violence experience, job stress, and burn-out, the score of job satisfaction was negatively correlated with the violence experience, job stress, and burn-out. With an analysis of the covariance structure, the job stress was more influential on the job satisfaction than violence experience and burn-out. In addition, a higher violence experience, job stress, and burn-out were found to decrease job satisfaction. On the other hand, a higher the job stress and violence experience resulted in higher burn-out rates. The results suggested that the job satisfaction is influenced more by job stress than by violence experience and burn-out. Therefore, concrete measures will be needed to reduce job stress and promote the job satisfaction of 119 rescue workers.

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.373-380
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• 2003

Most of low cost digital cameras reveal relatively high lens distortion. The purpose of this research is to compensate the degradation of image quality due to the geometrical distortion of a lens system. The proposed method consists of two stages : calculation of a lens distortion coefficient by a simplified version of Tsai´s camera calibration and subsequent image warping of the original distorted image to remove geometrical distortion based on the calculated lens distortion coefficient. In the lens distortion coefficient calculation stage, a practical method for handling scale factor ratio and image center is proposed, after which its feasibility is shown by measuring the performance of distortion correction using a quantitative image quality measure. On the other hand, in order to apply image warping via inverse spatial mapping using the result of the lens distortion coefficient calculation stage, a cubic polynomial derived from an adopted radial distortion lens model must be solved. In this paper, for the purpose of real-time operation, which is essential for embedding into an information device, an approximated solution to the cubic polynomial is proposed in the form of a solution to a quadratic equation. In the experiment, potential for real-time implementation and equivalence in performance as compared with that from cubic polynomial solution are shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.397-406
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• 2016

This study structurally analyzes the relations between children's pet attachment, empathy ability, and prosociality. The results are used to investigate the relations between pet attachment and empathy ability, which have recently emerged as important variables that affect children's prosociality. Data were collected about pet attachment, empathy ability, and prosociality from 209 elementary students in Daejeon who had experience with raising pets. SPSS 22.0 software was used for descriptive statistical analysis, correlation analysis, and reliability analysis, and AMOS 22.0 was used for confirmatory factor analysis and to examine the structural equation model. According to the analyses, children's pet attachment did not affect their prosociality but did influence their empathy ability. Children's empathy ability affected their prosociality and had a mediating effect on the relation between their pet attachment and prosociality. The results indicate that children's pet attachment and empathy ability are essential factors that influence prosociality. To improve prosociality, efforts should be made increase pet attachment and empathy ability. The study results can be used as a theoretical and practical fundamental basis for plans to improve children's pet attachment, empathy ability, and prosociality.

• Atmosphere
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• v.27 no.3
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• pp.359-370
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• 2017

In this study, the oceanic Total Precipitable Water (TPW) retrieval algorithm at 16 km altitude of High Altitude Long Endurance Unmanned Aerial Vehicle (HALE UAV) is described. Empirical equation based on Wentz method (1995) that uses the 18.7 and 22.235 GHz channels is developed using the simulated brightness temperature and SeeBor training dataset. To do radiative simulation, Satellite Data Simulator Unit (SDSU) Radiative Transfer Model (RTM) is used. The data of 60% (523) and 40% (349) in the SeeBor training dataset are used to develop and validate the TPW retrieval algorithm, respectively. The range of coefficients for the TPW retrieval at the altitude of 3~18 km with 3 km interval were 153.69~199.87 (${\alpha}$), 54.330~58.468 (${\beta}$), and 84.519~93.484 (${\gamma}$). The bias and RMSE at each altitude were found to be about $-0.81kg\;m^{-2}$ and $2.17kg\;m^{-2}$, respectively. Correlation coefficients were more than 0.9. Radiosonde observation has been generally operated over land. To validate the accuracy of the oceanic TPW retrieval algorithm, observation data from the Korea Meteorological Administration (KMA) Gisang 1 research vessel about six clear sky cases representing spring, autumn, and summer season is used. Difference between retrieved and observed TPW at 16 km altitude were in the range of $0.53{\sim}1.87kg\;m^{-2}$, which is reasonable for most applications. Difference in TPW between retrieval and observation at each altitude (3~15 km) is also presented. Differences of TPW at altitudes more than 6 km were $0.3{\sim}1.9kg\;m^{-2}$. Retrieved TPW at 3 km altitude was smaller than upper level with a difference of $-0.25{\sim}0.75kg\;m^{-2}$ compared to the observed TPW.