• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1141-1153
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• 2010

This paper introduces ONLIS(Overlay Multicast Network for Live IPTV Service), a novel overlay multicast network optimized to deliver live broadcast IPTV stream. We analyzed IPTV reference model of ITU-T IPTV standardization group in terms of network and stream delivery from the source networks to the customer networks. Based on the analysis, we divide IPTV reference model into 3 networks; source network, core network and access network, ION(Infrastructure-based Overlay Multicast Network) is employed for the source and core networks and PON(P2P-based Overlay Multicast Network) is applied to the access networks. ION provides an efficient, reliable and stable stream distribution with very negligible delay while PON provides bandwidth efficient and cost effective streaming with a little tolerable delay. The most important challenge in live P2P streaming is to reduce end-to-end delay without sacrificing stream quality. Actually, there is always a trade-off between delay & stream quality in conventional live P2P streaming system. To solve this problem, we propose two approaches. Firstly, we propose DSPT(Distributed Streaming P2P Tree) which takes advantage of combinational overlay multicasting. In DSPT, a peer doesn't fully rely on SP(Supplying Peer) to get the live stream, but it cooperates with its local ANR(Access Network Relay) to reduce delay and improve stream quality. When RP detects bandwidth drop in SP, it immediately switches the connection from SP to ANR and continues to receive stream without any packet loss. DSPT uses distributed P2P streaming technique to let the peer share the stream to the extent of its available bandwidth. This means, if RP can't receive the whole stream from SP due to lack of SP's uploading bandwidth, then it receives only partial stream from SP and the rest from the ANR. The proposed distributed P2P streaming improves P2P networking efficiency.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.1
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• pp.31-35
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• 1975

In order to gain information on the plant characteristics of high yielding paddy from the point of view of mineral nutrition and to learn more about soil conditions under which high yields are produced a number of soil samples collected from the field experiment carried out in The City College of Seoul were analysed. In addition, a laboratory experiment carried out to support the field experiment was also analysed. Results obtained are as follows: 1. Generally, the higher the yield of paddy, the higher is the potassium content in flag leaves, whereas the reverse is true for the content of Ca and Mg in the leaves. From these facts it can conceivably be said that the high yielding paddy should absorb a large quantity of potassium and a lesser quantity of calcium and magnesium in the reproductive stage. 2. Leaves of paddy which produced yields over 600kg/10a (a comparatively high yield in the experiment) contained 30-35mg/100g of potassium, less than 25me/100g of calcium, and 10me/100g of magnesium which brings the ratio of $K/{\sqrt{Ca+Mg}}$ over 5. 3. Correlation studies indicated a remarkable relationship between the paddy yield and exchangeable potassium in soil samples taken after harvesting. A similar relationship was observed between the yield of paddy and $K/{\sqrt{Cae+Mge}}$ ratio of the soil samples. 4. A regression between yield of padcy (Y) and exchangeable potassium (Ke) or $K/{\sqrt{Ca+Mg}}$ in soil samples taken after harvesting was shown to be; Y=183.95+2135.86Ke $$Y=352.45+3114.454\;K/{\sqrt{Ca+Mg}}$$ 5. The regression between exchangeable potassium (Ke) in soil samples taken after harvesting and the amount of lime (L) and potassium (P) to be applied is; $$Ke=0.1246+0.00007037L+0.004444P+0.000004444L{\cdot}P$$.

• The KIPS Transactions:PartC
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• v.18C no.5
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• pp.343-360
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• 2011

The objective of this paper is to analyze and characterize to simulate routing observations on end-to-end routing circuits and a ping experiment of a virtual network after modeling, such as IPv6 migration, an OSPFv3 routing experiment based on an IPv6 environment, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing using IPv6 planning and operations in an OPNET Modeler. IPv6 deployment based largely on the integrated wired and wireless network was one of the research tasks at hand. The previous studies' researchers recommended that future research work be done on the explicit features of both OSPFv3 and EIGRP protocols in the IPv4/IPv6 environment, and more research should be done to explore how to improve the end-to-end IPv6 performance. Also, most related work was performed with an IPv4 environment but lacked studies related to the OSPFv3 virtual network based on an end-to-end IPv6 environment. Hence, this research continues work in previous studies in analyzing IPv6 migration, an OSPFv3 routing experiment based on IPv6, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing. In the not too distant future, before enabling the default IPv6, it would help to understand network design and deployment based on an IPv6 environment through IPv6 planning and operations for the end-user perspective such as success or failure of connection on IPv6 migration, exploration of an OSPFv3 routing circuit based on an end-to-end IPv6 environment, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing. We were able to observe an optimal route for modeling of an end-to-end virtual network through simulation results as well as find what appeared to be a fast ping response time VC server to ensure Internet quality of service better than an HTTP server.

• Journal of Korean Home Economics Education Association
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• v.32 no.3
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• pp.81-96
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• 2020

This study aims to identify implications for the role of home economics in consumer education in middle schools focusing on building consumer competency. To this end, the content in middle school textbooks of home economics and other subjects, written according to the 2015 revised curriculum, were analyzed. This study examined consumer education content based on the consumer competency measurement index developed by the Korean Consumer Agency, and reviewed different foci presented by subjects. This study also investigated how the knowledge, attitude and practice, which are components of consumer competency, are presented. The major findings of this study can be summarized as follows: First, consumer competency content, presented in textbooks of home economics and other subjects, were comprised of citizenship competency(65.3%), transactional competency(27%), and financial competency(7.7%). Second, in terms of content on the consumer's citizenship competency, little attention was paid to consumer rights, revealing an imbalance between responsibilities and rights. Third, despite its importance, the "utilization of information and communications technology" in transaction competency, and "consumer participation" in citizenship competency are insufficiently covered in the home economics. Fourth, social studies was the subject that most extensively covered the content of consumer competency. In terms of scope, home economics dealt with most of the sub-fields. Fifth, even when the same content of consumer competency was covered, it was presented differently by subject. Sixth, there was a lack of connection between components of consumer competency-knowledge, attitude, and practice, with a disproportionately high emphasis on knowledge. In conclusion, this study concluded that consumer education content of middle school subjects is insufficient to enhance consumer competency.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.24-33
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• 2020

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

• Journal of Educational Research in Mathematics
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• v.22 no.1
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• pp.1-22
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• 2012

The purpose of this study is to understand Korea students' characteristics as well as to give important information of improving our education using comparative analysis of framework, test booklets, test results between PISA 2009 and NAEA 2009. PISA 2009 was administered on May of 2009 and NAEA was administered on October of same year. The summary of the results of comparing two assessment is as follows First, cut score of NAEA Advance level is bigger than the cut score of level 5, which is considered as high achievement level. The cut score of Basic level of NAEA is also higher than the level 2 of PISA, which is considered as basic achievement level. This phenomenon can show that NAEA achievement level is set little bit higher than the achievement level of PISA in mathematics domain. Second, the percentage of female students on higher level was higher than that of male students. In suburban area, the percentage of high level was small and the percentage of low level was big. Third, students of Advanced level are distributed concentrating in PISA levels 4~6, Proficient achievement level concentrating in PISA levels 3~5, Basic achievement level concentrating in PISA levels 2~4, and below basic achievement levels concentrating in below level 1 and level 3 of PISA. Fourth, the correlation between NAEA 2009 and PISA 2009 achievement scores are significantly positive. However, the correlation of subscales were low. Fifth, analysis of non-equivalent group, 11 items located in 'change and relationship', 'uncertainty', 'connection cluster' domains found to be significantly different. The percent correct showed very big difference. The analysis results presents the implication of mathematics curriculum, teaching and learning methods as well as National Assessment of Educational Achievement.

• Korean Journal of Health Education and Promotion
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• v.1 no.1
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• pp.21-36
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• 1983

It is assumed that menarche is affected not only by the biological factors such as nutrition and genetic heritage, but also it is affected by other socio-cultural environmental factors including weather, geographic location, education and level of modernization. Also recent trend of menarche in Korea indicates that a lot of discussion are being generated to the need of sex education as a part of formal school education. The purpose of this study is to develop the school health education program by determine the age of menarche, the factors relavant to time of menarche and psycho-mental state of students at the time in menarche and investigate the present state of school health education relate to menarche of adolescents. The total number of 732 girls was drown from first, second and third grades of 4 middle schools in Seoul. For the data collection the survey was conducted during the period from May 1 to May 20, 1982 by using prepared questionair. The major results are summarized as follow; 1. Mean age at menarche and the percent distribution of menarche experienced. It was observed that about 68.7% of sampled students have been experienced menarche at the time interviewed. For the each group, age at menarche is revealed that among the students about 37.8% are experienced menarche for under 12 years old group, 62.1% for 13 year-old group, 80.6％ for 14 year-old group and 95.5% for over 15 years old. In sum it was found that the mean age at menarche was 12.3 years old, ranged from age at 10 as earlist the age at 15 as latest. 2. Variables associated with age at menarche. 1) There was tendency those student who belong to upper class economic status have had menarche earlier than those student who belong to lower class. Therefore, economic status is closely related to age at menarche. 2) In time of mother's education level, it is also found that those students whose mother's education levels from high school and college are experienced menarche earlier than those students whose mother's education levels from primary school and no-education. 3) However, in connection with home discipline, there was no significant relationship between age at menarche and home disciplines which are being treated "Rigid", "Moderated ", "Indifferent". 4) Degree of communication between parents and daughter about sex matters was found to be associated each others in determination of age at menarche. 5) It was found that high association between mother's menarche age and their daughter's menarche age was observed. Mother's age at menarche earlier trend to be shown also as earlier of their daughters. 6) Those students belong to "D & E" of physical substantiality index are trend to be earlier in menarche than those students in the index "A & B". 3. Psycho-mental state at the time of menarche. Out of the total students 68.2% had at least one or more than one of subjective symptoms. Shyness was shown as most higher prevalent symptom and others are fear, emotional instability, unpleasant feeling, depression, radical behavior, inferior complex and satisfaction appeared. Very few cases are appeared be guilty and stealing feeling. 4. The present status of school health education program related to menarche. As to the source of information about menarche, teacher was a main source with average index 5.88 and the other informants were mother & family member, friends, books and magagines, movies, television, and radio. For the problem solving at menarche, mother & family members were subject to discussion with an average index 6.02 as high. The others for discuss and knowledge about menarche were books, magagine, friends, teachers, and self-learning based on own experienced. The time of learning about menarche, it was learned as highest percentage with 43.2% at a 6 grades of primary school, middle school with 34.4%, 5 grade of primary school with 18.2%, and 4 grade of primary school with 4.0% respectively.

• Journal of Korean Academy of Nursing
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• v.24 no.1
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• pp.58-69
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• 1994

In order to see the development of Nursing related research activities in Korea over the last three decades, abstracts of almost all of the Master and Ph.D theses that appeared from 1961 up to August 1991 were collected. The number of theses was 2354, from which an index of key words has been constructed. Key words were defined as those terms in each thesis title that convey major objectives of the given thesis study and the important nursing concepts dealt with in the thesis. Although all the key words were picked from the thesis title only, full use was made of the abstracts in deciding the principal objectives and essential contents of the thesis studies and their important concepts as well. In total, 539 kinds of key words were identified from the 2354 titles, and the identified words were all found to be in the International Nursing Index. On an average each title has two key words. Which key words were most frequently used, how they have changed with time, what kind of concept is preferably dealt with by each graduate school, and the concepts to which a given key word is likely to be connected were examined. The results are summerized below : 1) For each decade the theses numbers were as follows : 54(2.3%) from the 60’s, 413(17.5%) from the 70’s, 1523(64.7%) from the 80’s, and 364(15.5%) from the 90’s. Master’s thesis contributed 96% (2252) of the papers and Ph. D’s theses filled the remaining 4%(102). 2) A total of 539 key words were used, averaging about 2 for each thesis. The most frequently used key words were ‘Nurse’, ‘Anxiety’, ‘Knowledge / Attitude /Practice’, ‘Stress /Stressor’, ‘Attitude’, ‘Job-Satisfaction’, ‘Mental Disorder’, ‘Operation’, ‘Elderly’, ‘Nursing Role’. 3) Each decades key words can be classified as : the 60’s : ‘Nursing Education’, ‘Pulmonary Tuberculosis’, ‘Mother-Child Health’, ‘Growth & Development’, ‘Public Facilities’, ‘Mental Disorder’ : the 70’s : ‘Nurse’, ‘Family Planning’, ‘Attitude’ / ‘Knowledge, Attitude / Practice’, ‘Curriculum in Nursing Education’, ‘Clinical Practice in Nursing’, ‘Analysis of the Work of the Nurse’, ‘Health Education of School’, : the 80’s : ‘Nurse’, ‘Anxiety’, ‘Stress /Stressor’, ‘Operation’, ‘Nursing Role’, ‘Job Satisfaction’ : the 90’s : ‘Nurse’, ‘Elderly’, ‘Family-Support’, ‘Stress /Stressor’, ‘Home Care’. Key word ‘Nurse’ appears continuously and most frequently through the years, which indicates that there has been active study of the characteristics of nurses and related fields. The concept ‘Anxiety’ has been studied steadly from the 80’s and it shows that interest in health and disease are increasing Which comes as a result of society changing to an industrial and informational community. 4) Looking into each graduate school’s study area key words ‘Anxiety’, ‘Nurse’, ‘Mental Disorder’, ‘Stress /Stressor’, ‘Operation’, ‘Attitude’, ‘Hemo-dialysis’, were studied in the regular graduate school : ‘Family Planning /Contraception’, ‘Knowledge / Attitude /Practice’, ‘Physical Health-State /Physical Health Examination’, ‘Nurse’, ‘Using Clinical Facilities’, ‘Health Education of School’, were studied in the Graduate School of Public Health’ ; ‘Nurse’, ‘Anxiety’, ‘Stress / Stressor’, ‘Job-Satisfaction’, ‘Clinical Practice Education’, ‘Nursing Education’, were studied in the Graduate School of Education : ‘Nurse’, ‘Job Satisfaction’, ‘Nursing Role’, ‘Administration - Employment /Employment Management’, ‘Leadership’, ‘Personnel Profile’, ‘Nursing Manpower / Changing Working Place’, were studied in the Graduate School of Public Administration. 5) The Connection between key words were : ‘Nurse Job Satisfaction’, ‘Stress / Stressor ⇔ Coping / Ajustment’, ‘Nurse ⇔ Nursing Role’, ‘Anxiety ⇔ Giving Information’, ‘Nurse ⇔ Stress / Stressor’, ‘Anxiety ⇔ Operation’, ‘Nurse ⇔ Burnout’, ‘Knowledge, Attitude, Practice ⇔ Family Planning’, ‘Nurse Administration ⇔ Employment’, ‘Anxiety Muscle ⇔ Relaxation Technic’, ‘Anxiety ⇔ Mental Disorder’. From the above it can be noted that many nursing concepts were handled in the thesis titles. But there were more than enough papers on the characteristics of the nurse. It is suggested that in depth research be made on ‘Nursing Accidents’, t-‘Ethics’, ‘Nurse - Patient Interactions’, ‘Spritual Care’, ‘Dying’, ‘Hospice’, ‘Resident Helper’ and that there should be in depth research relating to the physical and mental development of youth and in particular physical concepts like ‘Drug - Abuse’, ‘Child -Abuse and Teaching’.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.143-150
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• 2012

A simulation methodology and corresponding program based on it is to be discussed for analyzing the effects of the networking operation of existing DHC system in connection with CHP system on-site. The practical simulation for arbitrary areas with various building compositions is carried out for the analysis of operational features in both systems, and the various aspects of thermal energy grids with connecting operation are highlighted through the detailed assessment of predicted results. The intrinsic operational features of CHP prime movers, gas engine, gas turbine etc., are effectively implemented by realizing the performance data, i.e. actual operation efficiency in the full and part loads range. For the sake of simplicity, a simple mathematical correlation model is proposed for simulating various aspects of change effectively on the existing DHC system side due to the connecting operation, instead of performing cycle simulations separately. The empirical correlations are developed using the hourly based annual operation data for a branch of the Korean District Heating Corporation (KDHC) and are implicit in relation between main operation parameters such as fuel consumption by use, heat and power production. In the simulation, a variety of system configurations are able to be considered according to any combination of the probable CHP prime-movers, absorption or turbo type cooling chillers of every kind and capacity. From the analysis of the thermal network operation simulations, it is found that the newly proposed methodology of mathematical correlation for modelling of the existing DHC system functions effectively in reflecting the operational variations due to thermal energy grids with connecting operation. The effects of intrinsic features of CHP prime-movers, e.g. the different ratio of heat and power production, various combinations of different types of chillers (i.e. absorption and turbo types) on the overall system operation are discussed in detail with the consideration of operation schemes and corresponding simulation algorithms.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.959-974
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• 2021

Forel-Ule Index (FUI) is an index which classifies the colors of inland and seawater exist in nature into 21 gradesranging from indigo blue to cola brown. FUI has been analyzed in connection with the eutrophication, water quality, and light characteristics of water systems in many studies, and the possibility as a new water quality index which simultaneously contains optical information of water quality parameters has been suggested. In thisstudy, Ocean Colour-Climate Change Initiative (OC-CCI) based 4 km FUI was spatially downscaled to the resolution of 500 m using the Geostationary Ocean Color Imager (GOCI) data and Random Forest (RF) machine learning. Then, the RF-derived FUI was examined in terms of its correlation with various water quality parameters measured in coastal areas and its spatial distribution and seasonal characteristics. The results showed that the RF-derived FUI resulted in higher accuracy (Coefficient of Determination (R²)=0.81, Root Mean Square Error (RMSE)=0.7784) than GOCI-derived FUI estimated by Pitarch's OC-CCI FUI algorithm (R²=0.72, RMSE=0.9708). RF-derived FUI showed a high correlation with five water quality parameters including Total Nitrogen, Total Phosphorus, Chlorophyll-a, Total Suspended Solids, Transparency with the correlation coefficients of 0.87, 0.88, 0.97, 0.65, and -0.98, respectively. The temporal pattern of the RF-derived FUI well reflected the physical relationship with various water quality parameters with a strong seasonality. The research findingssuggested the potential of the high resolution FUI in coastal water quality management in the Korean Peninsula.