• Journal of Science Education
• /
• v.34 no.1
• /
• pp.1-11
• /
• 2010

This study analyzes the factors influencing academic achievement on mathematic and scientific subject and its change in Korean youth by using a sample from KYPS(Korea Youth Panel Survey) data. The results are as follows: First, academic achievement on mathematic and scientific subject of Korean youth shows quadratic curve that their interrelationship between intercept and slope of academic achievement are negative which is statistically significant. Second, analysis of Latent Growth Models shows that parents, teacher, peer group, self esteem, income of family, high school tracks are found to be a statistically significant factor on mathematic. And scientific subject is affected by parents, teacher, peer group, self esteem, income of family, high school tracks. Also, Interesting finding is that father's job is not significant to dependent variables. These findings show that academic achievement on mathematic and scientific subject of the Korean youth are the quadratic curve and influenced by parents, teacher, peer group, self esteem, income of family, high school tracks. To improve youth's mathematic and scientific, Korea educational fields and educators should have policy to care youth's relationship with parents, teachers and self esteem.

• Applied Chemistry for Engineering
• /
• v.16 no.4
• /
• pp.474-484
• /
• 2005

Biological treatment is a promising alternative to conventional air pollution control methods. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing volatile organic compounds and odor compounds. They offer several advantages over traditional technologies such as incineration or adsorption. These include lower treatment costs, absence of formation of secondary pollutants, no spent chemicals, low energy demand and low temperature treatment. The most widely used bioreactor for air pollution control is biofilter, but it has several limitations. In the past years major progress has been accomplished in the development of vapor phase bioreactor, in particular biotrickling filters. Biotrickling filters are more complex than biofilters, but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. While the level of understanding of biotrickling filtration process for VOCs still remains limited, the evident success of biotreatment of VOC in air stimulated the pursue of acitve research. This paper presents fundamental and theoretical/practical aspect of air pollution control in biotrickling filter. Special emphasis is given to the operating parameters and the factors influencing performance for air pollution control in biotrickling filter.

• Journal of Bio-Environment Control
• /
• v.12 no.3
• /
• pp.107-113
• /
• 2003

This study was carried out to improve the performance of pre-developed heat recovery devices attached to exhaust-gas flue connected to combustion chamber of greenhouse heating system. Four different units were compared in the aspect of heat recovery performance; A-, B-, and C-types are exactly the same with the old ones reported in previous studies. D-type newly developed in this experiment is mainly different with the old ones in its heat exchange area and tube thickness. But airflow direction(U-turn) and pipe arrangement are similar with previous three types. The results are summarized as follows; 1. System performances in the aspect of heat recovery efficiency were estimated as 42.2% for A-type, 40.6% for B-type, 54.4% for C-type, and 69.2% for D-type. 2. There was not significant improvement of heat recovering efficiency between two different airflow directions inside the heat exchange system. But considering current technical conditions, straight air flow pattern has more advantage than hair-pin How pattern (U-turn f1ow). 3. The main factors influencing on heat recovery efficiency were presumably verified to be the total area of heat exchange surface, the thickness of ail-flow pipes, and the convective heat transfer coefficient influenced by airflow velocity under the conditions of allowable pipe durability and safety. 4. Desirable blower capacity for each type of heat recovery units were significantly different to each other. Therefore, the optimum airflow capacity should be determined by considering in economic aspect of electricity required together with the optimum heat recovery performance of given heat recovery systems.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.1
• /
• pp.40-48
• /
• 2017

RC flat plates may be governed by a serviceability as well as a strength condition, and a construction sequence and its impact on the distributions of gravity loads among slabs tied by shores are decisive factors influencing short and long term behaviors of flat plate. Over-loading and tensile cracking in early-aged slabs significantly increase the deflection of a flat plate system under construction, and a reshoring work may be helpful in reducing slab deflections by controlling the vertical distributions of loads in a multi-shored flat plate system. In this study, a effect of reshoring works on short and long term deflections of flat plate systems are analyzed. The slab construction loads with various reshoring schemes and slab design and construction conditions are defined by a simplified method, and the practical calculation of slab deflections with considering construction sequences and concrete cracking and long term effects is applied. From parametric studies, the reshoring works are verified to reduce slab deflections, and the optimized conditions for the reshoring works and slab design and constructions are discussed.

• Journal of Gifted/Talented Education
• /
• v.22 no.3
• /
• pp.757-777
• /
• 2012

Peer relationships in young students' communities are one of the important factors influencing the cognitive and affective domains of learning. Moreover, students who join the special program for gifted students possess differential peer relationships from the students in general classes. This study aims to explore the differences of 5th grade five science-gifted students' peer relationships between students in special classes for gifted students and general classes. Five students in the special program for gifted students, managed by the Office of Education in a southern city, participated in this study. Social network analyses were utilized to explore participants' peer relationships; the students' homeroom teacher was interviewed to explore the contextual and in-depth characteristics of gifted students' peer relationships. The results illustrated four cases of peer relationships: (1) smart loner (2) my study mate (3) I'm the best in my class, and (4) a good friend anywhere. This study identified that the gifted students possessed diverse peer relationships in both the special program and general classroom. In addition, this study suggests that the program for gifted students needs to be specially designed based on the gifted students' peer relationship.

• Journal of the Korean Geotechnical Society
• /
• v.34 no.7
• /
• pp.5-15
• /
• 2018

The unconfined compressive strength (UCS) test through coring is widely used to determine the reinforcement effect of the ground with grouting. However, the UCS test through coring can disturb the ground, is expensive and takes a lot of time to prepare the specimen. In this study, the factors affecting UCS of microfine cement grouted sand are evaluated and an empirical equation of UCS of microfine grouted sand is suggested. It is observed that UCS increases linearly until 28 days, however, the increasing rate of strength decreases sharply after that 28 days. The W/C ratio is dominant factor influencing UCS and UCS increases exponentially with the decrease of water/cement (W/C) ratio. Also, UCS increases linearly with increasing the relative density ranging from 30% to 70% and with decreasing median particle size. However, in case of W/C ratio=1 and K6 ($D_{50}=0.47mm$), UCS is lower than that of K4 ($D_{50}=1.08mm$) and K5 ($D_{50}=0.80mm$) due to filtration effect. Based on the experimental results, the empirical equation of UCS of microfine cement grouted sand can be expressed as the function of median particle size ($D_{50}$), porosity (n) and W/C ratio.

• Korean Journal of Health Education and Promotion
• /
• v.19 no.4
• /
• pp.1-18
• /
• 2002

This study identified the health habits affecting health status of industrial workers. Data was collected from 965 workers in 58 companies at Buchon. The research conducted a self-administered questionnaire survey and obtained the workers' health examination records. The results were as follows: 1. Among 965 respondents, men were 82.4%, women were 17.6%, 44.5% were of the 30${\sim}$40 age group, the married were 67.4%, the single were 30.8%, high school graduates were 81.1% and 38.8% were of people who worked between 1 and 5 years 2. As far as the seven health habits, current smokers were 52.8%, people who regularly exercise was 28.5%, 7${\sim}$8 hour of sleep, on the average were 71.4%, people eating breakfast nearly every day were 8.8%, and people eating between meals almost every day were 46.5%. Heavy drinkers who drink 3${\sim}$4 times or more per week were 14.2%, 1${\sim}$2 times per week were 32.6% and the obese were 9.3%. 3, Health status of A and B, estimated by doctors in the health examination were 80.8% and C, D1, D2, the unhealthy were 19.2%. For men, those who reported more than women in unhealthy groups and the results regarding health status reflects those for gender, educational level and age. That is to say that, lower educational level group and over 30 years of age group perceive their health to be worse than the higher educational level and under 30 age group. And these differences were statistically significant. 4. The relationship between health habits and health status were examined based on the odds ratio. Current smokers had a consistently worse health status than a non smokers with a 1.98 odds ratio. The workers who reported eating breakfast rarely or never were more associated with the unhealthy group than the regular breakfast eating group with a 2.96 odds ratio. One or more drink per week had a worse health status than a never or a little drinker with a 1.56 odds ratio. 5. General health habit score and duration of work were selected as significant factors influencing health status from the result of logistic regression analysis. According to the results of this model, the odds ratio of good health status was 2.08 for good health habit score, 1.63 for workers who worked five years or more duration at work. In summary, good health habits were associated with good health status. In particular, the workers who had 5 or more desirable health habits had a significantly better health status than the workers who had 4 or less than 4 good health habits. Therefore, in order to provide the health promotion programs to workers it is necessary to organize clear health management plans based on effective health education and health service perspective. If further research examines health habits and health status using a prospective study design, More precise findings for health promotion program development in the worksite and worksite health management planning.

• Korea Journal of Hospital Management
• /
• v.22 no.2
• /
• pp.28-43
• /
• 2017

The purpose of this study was to investigate the influence of professional self-concept and interpersonal relations on nursing competence of clinical nurses. This study was conducted as a descriptive cross sectional survey with 182 nurses who work at a tertiary hospital which has over 1,000 beds, located in Gyeounggi - do. The data was collected from October 11th, 2016 to October 28th, 2016. The main findings of this study were as follows. The mean score for professional self-concept was $2.65{\pm}0.29$ points in the range of 1 point to 4 points. And interpersonal relations was an average of $3.55{\pm}0.35$ points in the range of 1 point to 5 points. Nursing competence was an average of $2.65{\pm}0.39$ points in the range of 1 point to 4 points. Professional self-concept and interpersonal relations were positively correlated with nursing competence. Nursing competence was differed from clinical career(F=10.518, p<.001), working unit(F=4.139, p=.018), educational background(F=6.542, p=.002), and satisfaction on nursing(F=6.326, p<.001). The regression model with clinical career, working unit, educational background, satisfaction on nursing, 3 sub domain of professional self-concept(professional practice, satisfaction, communication), and interpersonal relation was statistically significant (F=31.94, p<.001). And this model could explain 51.5% of nursing competency(Adj R2=.515). Especially, professional practice(${\beta}=.532$, p<.001) of professional self-concept, interpersonal relations(${\beta}=.223$, p<.001), clinical career(${\beta}=.169$, p<.001), working unit: ICU (${\beta}=.169$, p<.05) were identified the factors influencing on nursing competence. Therefore, improving clinical nurses' nursing competence can be achieved with broad approach that includes improvements in professional self-concept and interpersonal relations. And also, working unit, and clinical career should be considered to develop the actual program for nursing competence, too.

• KSBB Journal
• /
• v.20 no.3
• /
• pp.205-209
• /
• 2005

Studies for the commercial production of sesame oil using th supercriticl carbon dioxide were made. Characteristics of sesame oil containing one of natural antioxidant 'sesamol', which only exist at sesame seed were also studied during the supercritical fluid extraction. Among the various factors influencing the sesamol contents in the sesame oil, the roasting time and temperature were checked, because sesamol can be converted from sesamol in through pyrolysis. We found that the sesamol content was increased rapidly under the condition of roasting temperature over $200^{\circ}C$ with longer roasting time. The sesamol content was increased as the temperature and pressure increased, which was caused by increase of solubility of sesamol against sesamol oil. And the sesamol content was increased also with lower speed of supercritical fluid, which increased the contact time with the raw material. The sesamol content was also increased using water increase up to $1\%$ as the entrainer. When the extraction performance with the supercritical fluid was compared to the conventional compressed extraction, the sesamol content was increased up to 11.5 times with the entrainer.

• KSBB Journal
• /
• v.9 no.5
• /
• pp.483-491
• /
• 1994

It is known that a key limiting factor to the use of ultrafiltration membranes is that of membrane fouling, which has been a major cause of permeate flux reduction. In this work, the effects of several factors (operating time, protein concentration, temperature and pH, etc.) influencing permeate flux during ultrafiltration of gelatin, casein and bovine serum albumin using a hollow fiber membrane(M. W. 10,000 cut off) reactor have been examined. The permeate flux of gelatin solution was maintained almost constant during the operation up to 6 hours, but those of casein and albumin solutions were decreased to 50% and 43% of initial value after an operation time of 60min. The permeate flux with increasing concentration and temperature of protein solutions increased, but the permeate flux showed a minimum value near the isoelectric point of proteins. The permeate fluxes of protein solution were enhanced by a temperature increase and pH control. Also, it is proposed that fouling can be decreased by the pretreatment of insoluble proteins with enzymes.