• 농업과학연구
• /
• 제32권2호
• /
• pp.107-126
• /
• 2005

The most limited production resource in Korea is land. During the period from 1995 to 2002, annual farm land area of 17,600ha have been converted to urban and industrial land. The self-sufficiency rate of rice, Korean staple food, is expected to be decreased from 97.5% in 2003 to 60-70% in 2020. Under such conditions, this study is aimed at first identifying multi-functional benefits of the reclamation projects such as agricultural production, industrial water supply, urban land supply, transportation effects, sightseeing effects and environmental values with and without the projects. To carry out the objectives, three existing tideland reclamation projects such as Daeho, Kumgang and Yongsangang irrigation project stage II were evaluated and Saemangeum tideland reclamation project which was jointly revaluated by environmental NGO and Govn't appointed specialists in 2000 was reviewed. According to this study results, tide land reclamation projects were showed financially and economically feasible and environmentally sustainable. The joint cost like estuary dam should be allocated based on the multi-functional benefits of the projects. To allocate the joint cost, legal and institutional improvement should adapt the joint cost allocation method as the specific cost-remaining benefit method. Korea has more than 402,000 ha of tidal flat of which 76,396ha have been reclaimed in 2003. To meet food security and to cope with shortage of land, phil-environmental reclamation projects should be continuously implemented and necessary tidal flats for protecting environmental ecosystem should be remained according to the detail survey results of reclaimable resources.

• 한국도로학회논문집
• /
• 제19권2호
• /
• pp.113-126
• /
• 2017

PURPOSES : This study proposes standards for rural access road pavement section and thickness design considering existing access road construction conditions; the study also proposes a complementary policy that can be used for design convenience. METHODS : Various literature review and case studies had been performed in terms of rural access road section and thickness design, both domestically and internationally, and this was followed by domestic rural access road field surveys. KPRP and KENLAYER were used to analyze the commonalities and predict the remaining life. Data on real cost is used to select an appropriate construction method through economic analysis. RESULTS : The economic efficiency of concrete pavement ($15{\times}15$) was the highest in terms of economic efficiency of performance life and traffic volume. In the case of asphalt pavement, it is considered that the most economical method is to implement micro-surfacing method four times as a preventive maintenance method (once every 10 years and 4.5 years for asphalt concrete pavement and MS construction method, respectively). Repairable asphalt pavement is advantageous for areas where heavy vehicles are expected to pass. In the case of other general areas, it is considered economical to place concrete ($15{\times}15$) pavement. However, as analytical results on its performance life are unavailable, it is to be considered for study in the future. CONCLUSIONS : This study proposed interim design guidelines based on various domestic and international design guidelines and case studies. However, in order to develop the final design criteria applicable to the field, it is necessary to (a) estimate the bearing capacity of the lower level of the pavement at various sites, (b) estimate the daily traffic volume, (c) implement advanced low-cost pavement technologies, and (d) propose maintenance standards and techniques for long-term performance.

• 한국해양공학회지
• /
• 제22권5호
• /
• pp.100-105
• /
• 2008

A106 Carbon Steel has recently been used as the material for pipes, nozzles, and tank shells in nuclear power plants. Its corrosion resistance gives the steel many advantages for use in structures under high temperature and high pressure. This steel is also expected to be used as a structural material in the shipbuilding industry for applications involving severe conditions, such as high temperature and pressure. In this study, the mechanical properties of A106 carbon steel were evaluated in regard to its corrosion times. The tensile and yielding strengths decreased as the corrosion time increased. In particular, the tensile strength was influenced by corrosion. In addition, an acoustic emission (AE) technique was used to clarify the microscopic damage to specimens that had undergone corrosion for a certain period. It was found that AE parameters, such as events, energy, duration time, and amplitude were useful for evaluating the degree of damage and remaining life of the corroded specimen. Various properties of the waveform and frequency range were also seen, based on the degree of damage to the specimen from the corrosion time.

• Journal of Information Technology Applications and Management
• /
• 제21권1호
• /
• pp.107-136
• /
• 2014

This study aims to suggest research implications that may contribute to preventing turnover of personnel in small and medium sized software companies. A research model is developed based on the Bergiel, et al. (2009) and Woo and Hwang (2010). This model describes how human resource management (HRM) practices (compensation, recognition, job autonomy, technical capability development, work-life conflict) affect turnover intention, through the mediating effects of job satisfaction and job embeddedness. 177 questionnaires are collected and analyzed. Validity and reliability of measures, and appropriateness of the structural model are verified. Results of the hypotheses testing are somewhat different from the expected ones: Only compensation and technical capability development are significant, but the remaining variables are not significant in affecting job satisfaction and job embeddedness. As for turnover intention, job embeddedness and job satisfaction are proved to be significant predictors. From the analyses of data, subsequent interview with several respondents and additional data analyses, more research implications are derived. The study has a limitation of not including more diverse variables that might affect job embeddedness and job satisfaction of so called road warriors.

• 산업경영시스템학회지
• /
• 제43권1호
• /
• pp.123-131
• /
• 2020

There have been a lot of studies in the past for the method of predicting the failure of a machine, and recently, a lot of researches and applications have been generated to diagnose the physical condition of the machine and the parts and to calculate the remaining life through various methods. Survival models are also used to predict plant failures based on past anomaly cycles. In particular, special machine that reflect the fluid flow and process characteristics of chemical plants are connected to hundreds or thousands of sensors, so there are not many factors that need to be considered, such as process and material data as well as application of derivative variables. In this paper, the data were preprocessed through time series anomaly detection based on unsupervised learning to predict the abnormalities of these special machine. Next, clustering results reflecting clustering-based data characteristics were applied to produce additional variables, and a learning data set was created based on the history of past facility abnormalities. Finally, the prediction methodology based on the supervised learning algorithm was applied, and the model update was confirmed to improve the accuracy of the prediction of facility failure. Through this, it is expected to improve the efficiency of facility operation by flexibly replacing the maintenance time and parts supply and demand by predicting abnormalities of machine and extracting key factors.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권1호
• /
• pp.31-37
• /
• 2019

Objective: At least eight local duck breeds have been recognized and documented as national germplasm of Indonesia so far. It is necessary to genetically characterize the local duck breeds for aiding conservation and future improvement strategies. Thus, this study was carried out to assess genetic diversity and phylogenetic relationship of eight local duck populations of Indonesia using microsatellite markers. Methods: In total, 240 individuals (30 individuals each population) from Alabio (AL), Bayang (BY), Magelang (MG), Mojosari (MJ), Pegagan (PG), Pitalah (PT), Rambon (RM), and Turi (TR) duck populations were genotyped using 22 microsatellite markers. Results: The results showed a moderate level of genetic diversity among populations, with a total of 153 alleles detected over all loci and populations, ranging from 3 to 22 alleles per locus. Observed (Ho) and expected heterozygosity (He), as well as polymorphism information content over all loci and populations were 0.440, 0.566, and 0.513, respectively. Heterozygote deficiency in the overall populations ($F_{IT}=0.237$), was partly due to the heterozygote deficiency within populations ($F_{IS}=0.114$) and moderate level of genetic differentiation among populations ($F_{ST}=0.137$). The most diverse population was MG (He = 0.545) and the least diverse population was AL (He = 0.368). The majority of populations were relatively in heterozygote deficiency (except AL), due to inbreeding. The genetic distances, phylogenetic trees, and principal coordinates analysis concluded that the populations can be grouped into two major clusters, resulting AL, MG, and MJ in one cluster separated from the remaining populations. Conclusion: The present study revealed a considerable genetic diversity of studied populations and thus, proper management strategies should be applied to preserve genetic diversity and prevent loss of alleles.

• 한국동물위생학회지
• /
• 제35권4호
• /
• pp.327-332
• /
• 2012

This study aimed to see if as companion animals living with human beings, dogs could provide emotional stability or play a therapeutic role for human beings. Of 12 middle school boys as victims of school violence, 6 were assigned to the experimental group that was provided with an animal-assisted therapy program over a total of 12 sections, one section per week, 60 minutes per section, between September and November 2011, followed by post-test 1 and, one month later, post-test 2. In the experimental composition, the remaining 6 boys were assigned to the comparison group that was allowed to read freely. Analysis was performed by using the scales of depression and self-esteem, and the results showed that the experimental group provided with the animal-assisted therapy program generated more significant therapeutic effects than the comparison group. The therapeutic effects were found to persist one month after the completion of the program. Therefore, it is believed that sensitive adolescents who suffer from depression or have lost self-esteem because of school violence can significantly benefit from an animal-assisted therapy program by reducing the recovery time or by getting lots of help with emotional stability. Further research on the basis of this study is expected to help adolescents with emotional therapy in other areas.

• 수산해양교육연구
• /
• 제27권5호
• /
• pp.1236-1251
• /
• 2015

This study examined understanding and attitude of sustainable development(SD) of 38 college students in a nuclear power plant construction after education for sustainable development(ESD) through panel discussion. The results were as follows: First, after lesson 66% of students were expected that SD is possible if scientific technology is developed and a frugal life for the protection of environment is carried out. However, the remaining students regarded SD as an ideal concept, because they thought it is not possible to pursue environmental sustainability and socio-economic development simultaneously. Second, students' opinions in the evaluation of constructing a nuclear power plant in three aspects(environment, society and economy) before and after panel discussion were changed as follows; 1) After panel discussion, the objectors increased to 21% in economic evaluation, while the supporters increased to 11% in environmental evaluation. 2) Students majoring in engineering or natural sciences changed their opinions to agree in environmental evaluation because they considered a nuclear power plant safe and eco-energy. However students majoring in social science/business or liberal arts/arts changed their opinions to disagree in economic evaluation because they considered a nuclear power plant as high-cost energy when assessing danger-accidents cost, public consensus cost, operation and maintenance cost, and waste disposal cost. 3) This change of decision-making in students majoring in social science/business or liberal arts/arts after panel discussion was statistically significant(p<0.05). Implications of panel discussion as a teaching and learning method in ESD are also discussed.

• 대한소아치과학회지
• /
• 제25권2호
• /
• pp.458-466
• /
• 1998

Non-odontogenic tumors can be classified as malignant or benign. Most oral tumors in children are benign. In the Belfast series only 7.5 percent of soft tissue tumors were malignant and Bhaskar(l963) found only 9 percent of 293 oral tumors of all kinds to be malignant. Benign tumors may be classified as epithelial and mesenchymal. The most common tumor of surface epithelium is the squamous papilloma. These are easily recognized clinically as cauliflower-like lesions. Fibrous lesions are very common in children's mouths. Many of these are not true neoplasms but are related to fibrous hyperplasia. Another common oral tumor in children is angiomatous tumors. Hemangioma occurred more frequently than lymphangioma. Cystic hygroma, a cystic subtype of lymphangioma, is a developmental tumor of lymphatic origin. It is a considered to be a relatively rare lesion. About 50 percent of cystic hygroma are present at birth, and most of the remaining 50 percent appear in the early years of life during the period of active lymphatic growth. The preferred treatment for these lesions, except for hemangioma, is complete surgical excision. With proper surgical techniques, recurrence is not expected.

• 한국자원식물학회지
• /
• 제27권6호
• /
• pp.660-670
• /
• 2014

The Korean plum yew (Cephalotaxus koreana Nakai) is a shade-tolerant, coniferous shrub. The seeds have been used as a folk medicine in Korea, and an alkaloid extract (HTT) is known to have anticancer properties. We estimated the genetic diversity of 429 trees in 16 populations in South Korea using 194 polymorphic amplicons from seven combinations of AFLP primer-restriction enzymes. The average number of effective alleles and the percentage of polymorphic loci were 1.37 and 79.4%, respectively. Shannon's diversity index and the expected heterozygosity were 0.344 and 0.244, respectively. We divided 16 populations into four groups on the UPGMA dendrogram and the PCA biplot. The first two principal components explained 84% of the total genetic variation. Genetic differentiation between populations explained 14% of total genetic variation, and the remaining 86% came from difference between individuals within populations, as determined by an analysis of molecular variance (AMOVA). However, the genetic differentiation did not correlate with the geographic distance between populations from the Mantel test. The Bayesian statistics, which are comparable to Wright's $F_{ST}$ and Nei's $G_{ST}$, were ${\theta}^I=0.406$ and ${\theta}^{II}=0.172$, respectively. The population genetic diversity was slightly lower, and the strength of genetic differentiation was much weaker, than the average of those plants having similar life histories, as assessed using arbitrary marker systems. We discuss strategies for the genetic conservation of the plum yew in Korea.