• Education of Primary School Mathematics
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• v.5 no.2
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• pp.121-142
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• 2001

The goal of the National Assessment of Educational Achievement(NAEA) 2001 was to affirm the accountability of school education, to scientifically manage and elevate the quality of education at the national level, and to articulate the final design of the NAEA. It was implemented on June 28th of the year 2001. The assessment frame for NAEA includes the achievement standards, the assessment standards, the instruction for the item development, and the grading policy for mathematics subject. Most of items are multiple-choice types, but the performance-based items should be at least thirty percent of the total items, also 30% in case of mathematics. Approximately 1% of students among entire population of the Grades 6 were randomly selected. Therefore, the finally sampled examines were 8023 at Grade 6. The result of the analysis of the NAEA revealed that Grade 6 students was labelled as ‘average’ level in general (Number and Operation: average, Geometric figures: average, Patterns and Functions: excellent, Measurements: average, Letters and Expressions: average, Probability and Statistics: average). The most characteristic finding was that except for Grade 6(its average is 69.92), most secondary students obtained low test scores and its average of each grade is below 50 out of 100. Especially, the scores on the performance-based items were by and large very low. This finding implies that Korean students are not familiar with the kind of test items which requires expression of ideas and feelings and they are rather familiar with the multiple-choice items. Another interesting finding was that the students in small towns and remote areas showed significantly low scores in all four skills compared with Seoul, metropolitan cities and medium and small cities. This may be attributed from the fact that the remote areas do not have equal learning environment with regard to social and cultural experience, supply of various teaching materials, extracurricular lessons which are directly related to teaching and learning. These findings may be utilized as a reliable resource fur improving curriculum and teaching and learning in Mathematics.

• Journal of Korean Foot and Ankle Society
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• v.16 no.4
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• pp.223-228
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• 2012

Purpose: To treat hallux valgus in old age patients with chevron metatarsal osteotomy and to see the subsequent clinical and radiological outcomes. Materials and Methods: 23 cases of 18 hallux valgus patients of age 60 years or older who received proximal or distal corrective osteotomy from April 2007 to August 2009 and were followed up for at least 1 year were included in the study. The mean age at operation was 65 years (range, 60~81 years), and the mean follow-up period was 2 years and 6 months (range, 1 year~3 years 6 months). Clinical outcome was assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, complications, satisfaction rate, as well as measurements and comparison of pre- and postoperative hallux valgus angles, the 1st~2nd intermetatarsal angle, and the position of hallucal medial sesamoid bone. Results: The AOFAS score was improved from preoperative average of 35.1 (range, 13-47) to average 85.1 at last follow-up (range, 75-100). Patients were satisfied about the operation in 21 cases (91.3%). Preoperative hallux valgus angle was $31.7^{\circ}$ on average (range, $19.1^{\circ}-48.9^{\circ}$), and $4.9^{\circ}$ on average at last follow-up (range, $0.3^{\circ}-21.2^{\circ}$). The 1st~2nd intermetatarsal angle was $14.4^{\circ}$on average (range, $8.7^{\circ}-25.7^{\circ}$) and $3.1^{\circ}$ on average at last follow-up (range, $0.6^{\circ}-7.5^{\circ}$). The hallucal medial sesamoid bone position was improved from preoperative average 3.5 (range, 3-4) to postoperative average 1.0 (range, 0-2). Conclusion: Proximal and distal metatarsal osteotomy treatment yielded good clinical and radiological outcomes in old age hallux valgus patients.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.865-874
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• 2002

HTTP (HyperText Transfer Protocol) is a transfer protocol used by the World Wide Web distributed hypermedia system to retrieve the objects. Because HTTP is a connection oriented protocol, it uses TCP (Transmission control Protocol) as a transport layer. But it is known that HTTP interacts with TCP badly. it is discussed about factors affecting the performance or HTTP over TCP, the transaction time obtained by the per-transaction TCP connections for HTTP access and the TCP slow-start overheads, and the transaction time for T-TCP (Transaction TCP) which is one or methods improving the performance or HTTP over TCP. Average waiting time and average turnaround time are important parameters to satisfy QoS (Quality of Service) of end users. Formulas for calculating two parameters are derived. Such formulas can be used for the environment in which each TCP or T-TCP transaction time is same or different. Some experiments and computational experiences indicate that the proposed formulas are well acted, can be applied to the environment which the extension of bandwidth is necessary, and time characteristics of T-TCP are superior to that of TCP. Also, the load distribution method of web server based on the combination of bandwidths is discussed to reduce average waiting time and average turnaround time.

• Journal of radiological science and technology
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• v.20 no.2
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• pp.73-78
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• 1997

The goal of this paper is that we know the usefulness of echo-planar imaging(EPI) for discriminate between hepatocellular carcinoma(HCC) and hemangioma. We get a time signal intensity curve for liver diseases from the dynamic contrast enhancement images and compared and analyze both the contrast ratio(CR) and the contrast to noise ratio(CNR) using echo planar imaging. The obtained results are follows : 1. Hepatocellular carcinoma was shown the best contrast after about 20 seconds when Is the earlist time in the main artery, and then reduced. The center where is disease was shown the characteristic that the best contrast is appeared after about 35-45 seconds and then slowly reduced. Liver parenchyma was shown the best contrast and reduced after 60 seconds. 2. The peripheral nodular of hemangioma was shown the better contrast soon. On the other hend, the contrast of center where is disease started to increase after 60 seconds and was equal to that of liver parenchyma. Increasing of the contrast continued after. 3. Turbo SE technic was used, the average of CR for hepatocellular carcinoma was $36.7{\pm}1.2$ and the average of CNR was $2.4{\pm}3.2$, while the average of CNR for hemangioma was $54.9{\pm}1.0$ and the average of CNR was $9.7{\pm}1.3$. 4. EPI technic was used, the average of CR for hepatocellular carcinoma was $47.8{\pm}1.2$ and the average of CNR was $3.4{\pm}2.1$, while the average of CNR for hemangioma was $75.7{\pm}2.2$ and the average of CNR was $9.5{\pm}1.1$. According to above we can find that hemangioma is more bright than hepatocellular carcinoma and the difference of brightness between hepatocellular carcinoma and hemangioma is useful sequence.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.81-94
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• 2023

The study aims to compare and analyze the social network structures of Qatar Airways,s Singapore Airlines, Emirates Airlines, and ANA Airlines, recording the top 1 to 4, and Korean Air in ninth by Skytrax's airline evaluations in 2022. This study uses NodeXL, a social network analysis program, to analyze the social networks of 5 airlines, Vertex, Unique Edges, Single-Vertex Connected Components, Maximum Geodesic Distance, Average Geodesic Distance, Average Degree Centrality, Average Closeness Centrality, and Average Betweenness Centrality as indicators to compare the differences in these social networks of the airlines. As a result, Singapore's social network has a better network structure than the other airlines' social networks in terms of sharing information and transmitting resources. In addition, Qatar Airways and Singapore Airlines are superior to the other airlines in playing roles and powers of influencers who affect the flow of information and resources and the interaction within the airline's social network. The study suggests some implications to enhance the usefulness of social networks for marketing.

• Korean Journal of Mathematics
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• v.22 no.3
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• pp.419-427
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• 2014

Let $k=\mathbb{F}_q(T)$ be the rational function field over a finite field $\mathbb{F}_q$, where $q{\equiv}1$ mod 3. In this paper, we determine asymptotic values of average of ideal class numbers of some family of cubic Kummer extensions of k.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.76-78
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• 1996

When data is classified and each class has weight, the mean of data is a weighted average. When the class values and weights are trapezoidal fuzzy numbers, we can prove the weghted average is a fuzzy number though not trapezoidal. Its 4 corner points are obtained.

• Honam Mathematical Journal
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• v.27 no.3
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• pp.505-513
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• 2005

The aim of this paper is to establish a functional central limit theorem for multivariate moving average process generated by negatively associated random vectors under the finite second moments.

• Journal of the Korean Statistical Society
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• v.32 no.1
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• pp.65-71
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• 2003

We consider the finite dam with compound Poisson inputs which is called M/G/1 finite dam. We assign some costs related to operating the dam and calculate the long-run average cost per unit time. Then, we find the optimal dam capacity under which the average costs is minimized.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.4
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• pp.631-638
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• 2011

In this paper, we prove that for $C^1$ generically, if every hyperbolic periodic point in a chain component is uniformly far away from being nonhyperbolic, and it is $C^1$-robustly average shadowable, then the chain component is hyperbolic.