• Journal of The Korean Association For Science Education
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• v.38 no.3
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• pp.331-341
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• 2018

The purpose of this study is to explore relationships among the structural elements of Science Classroom as Community of Practice (SCaCoP). For this, we investigated the case of small-group activities in practical work of elementary school science in a qualitative way based on the five structural elements of SCaCoP, such as responsibility for learning, common interest, open participation, mutual relationship, and practice. We observed and interviewed five small-groups during five lessons with video- and audio- recording to collect data. The results of analysis are as follows. First, 'mutual relationship' was a necessary-condition for 'open participation.' We also found that 'common interest' has two dimensions related to their interest and related to learning topic. The former interacted with 'open participation,' and the latter was influenced by 'responsibility for learning. Lastly, 'practice' enhanced the features of other elements with dynamic relationships. Based on these results, we suggested the relationships among the structural elements of SCaCoP and discussed implications related to the perspective that regards learning as participation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2202-2211
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• 2006

EXT3NS is a special-purpose file system for large scale multimedia streaming servers. It is built on top of streaming acceleration hardware device called Network-Storage card. The EXT3NS file system significantly improves streaming performance by eliminating memory-to-memory copy operations, i.e. sending video/audio from disk directly to network interface with no main memory buffering. In this paper, we design and implement a buffer cache mechanism, called PMEMCACHE, for EXT3NS file system. We also propose a buffer cache replacement method called ONS for the buffer cache mechanism. The ONS algorithm outperforms other existing buffer replacement algorithms in distributed multimedia streaming environment. In EXT3NS with PMEMCACHE, operation is 33MB/sec and random read operation is 2.4MB/sec. Also, the buffer replacement ONS algorithm shows better performance by 600KB/sec than other buffer cache replacement policies. As a result PMEMCACHE and an ONS can greatly improve the performance of multimedia steaming server which should supportmultiple client requests at the same time.

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.234-243
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• 2000

This study investigated the relationships between verbal behaviors and chemistry problem solving ability in cooperative learning. Based on the previous chemistry achievement. 11th-graders were assigned heterogeneously into three-membered groups. Small cooperative group problem solving processes in using 4 stage-problem solving strategy were audio/video taped. Students' chemistry problem solving ability was then measured by a problem solving strategy performance test. Their verbal behaviors were classified into giving information, receiving information, asking questions, and disagreeing. These were further coded into 16 subcategories. Providing, a subcategory of giving information, was the most frequent behavior. In studying partial correlation between verbal behaviors and problem solving ability, 7 categories were found to have significantly positive relationships. Providing showed the highest correlation with the problem solving ability as reported previously. Moreover, this study also revealed significant correlations in the categories of clarifying provided, correcting, justifying, and clarifying. In the case of low-ability students, the verbal behaviors of giving or receiving information were strongly correlated with problem solving ability. However, these verbal behaviors did not enhance the problem solving ability of high- and medium-ability students.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1274-1284
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• 1998

Multicasting plays an important role in providing multimedia services like audio and video conferencing and has been actively studied for many years. The study of multicasting has been mainly focused on finding a low-cost tree on the assumption that every edge of the tree has enough link capacity to be allocated to the amound of bandwidth required by a service. In some cases, however, a multicasting tree whose some edges do not have enough bandwidth to be allocated may exist. A typical example of this case is to multicast among the group users located in the different sub-networks in the interconnected networks composed of the high bandwidth networks such as B-ISDN and the low bandwidth networks such as PSTN and PSDN. This paper proposes a novel multicasting protocol for providing multimedia services in a wide area network interconnected by multiple heterogeneous networks. First, the paper discusses the inherent limitation of present multicasting protocols for the case. Second, se introduce a new concept, multiple QoS's for a service, which extends the implicit assumption that only one QoS is assigned to a service in order to overcome this limitation. Third, our multicasting protocol is designed based on the current Internet protocol stacks. Last, we perform simulations for possible scenarios to provide multimedia services in the network and analyze their pros and cons.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.470-480
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• 2001

The purpose of this study was to investigate the effects of science inquiry experiments emphasizing social interaction on the development of process skills of the students. The social interactions by cognitive level of the students were also analyzed. For this study, 197 8th grade students were sampled. They were divided into an experimental group and a control group. During four-month period, the experimental group received science inquiry experiments treatment emphasizing social interactions while the control group received traditional treatment. Not only science inquiry ability pretest-posttest, but also multiple data collection method such as a questionnaire, class observation, and audio/video recording were used in collecting the data. According to the results of this study, it was found that the mean score of the experimental group was significantly higher than that of the control group at 0.05 level. It was also found that the students of high cognitive level led the peers and participated in the class discussion actively with the teacher while the students of low cognitive level followed the students of high cognitive level and showed inactive interaction with the teacher. Analysis of the students' perceptions on inquiry experiments showed that students participated in discussion actively in the class as these experiments gave an opportunity for them to discuss and were able to solve the problems with peers' help through discussion.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.268-278
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• 2004

In this paper, we describe our experience in the design and implementation of the SMART file system to handle multimedia workload. Our work has three design objectives: (ⅰ) efficient support for sequential workload, (ⅱ) avoiding disk fragmentation, (ⅲ) logical unit based file access. To achieve these three objectives, we develop a file system where a file consists of linked list of Data Unit Group. Instead of tree like structure of the legacy Unix file system, we use single level file structure. Our file system can also access the file based upon the logical unit which can be video frame or audio samples. Data Unit Group is a group of logical data units which is allocated continuous disk blocks. At the beginning of each Data Unit Group, there exists an index array. Each index points to the beginning of logical data units, e.g. frames in the Data Unit Group. This index array enables the random access and sequencial access of semantic data units. SMART file system is elaborately tailored to effectively support multimedia workload. We perform physical experiments and compare the performance of SMART file system with EXT2 file system and SGI XFS file system. In this experiment, SMART file system exhibits superior performance under streaming workload.

• Journal of Korean Public Health Nursing
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• v.16 no.2
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• pp.304-314
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• 2002

A survey was conducted from September 15 to December 15 2001. Structured questionnaires were mailed to school nurses in 607 elementary schools around the country in order to determine the current status of anti-smoking education in elementary schools. The result were as followers 1. Of the 607 schools, 535 $(88.1\%)$ offered smoking-prevention education. By region, Jeju-do $(100\%)$ topped the list, followed by Seoul $(90.3\%)$, Gyeongsang-do$(90.2\%)$, Jeolla-do$(88.9\%)$, Gangwon-do $(87.8\%)$, Chungcheong-do $(84.6\%)$, and Gyeonggi-do $(81.4\%)$. 'Recognition of the need for anti-smoking program $(86\%)$' was a major motivation for initiating the program, while 'too much workload $(46.4\%)$' was cited as a main reason for the failure to do so. 2. The classes were offered mostly for 6th-grade students $(87.8\%)$, while $9.0\%$ and $2.0\%$ were implemented at 5th- and 4th- grades, respectively. 3. $49.1\%$ of the classes offered lasted one hour, while $31.8\%$ involved a two-hour program. 4. Programs were mainly about smoking-related diseases, habitual nature of smoking, impediment to growth and development, etc. 5. Audio-visual lecture $(46.5\%)$ was most frequently used as a method of education, followed by lecture. 6. $72.7\%$ of the programs used classroom as a unit of education, while collective education by sex or by grade accounted for $22.6\%$. 7. Video $(51.0\%)$ was the most popular medium for education, while computer ranked second with $26.5\%$. 8. $92.5\%$ of the education was offered by school nurses. 9. $99.2\%$ of school nurses responded in favor of anti-smoking programs. with $60.1\%$ of them answering that such education is a must. 5th grade was the most commonly cited grade for the initiation of the programs, followed by 4th grade and 6th grade. $33.2\%$ picked two hours as the most appropriate length of the program at the elementary school level. while $25.1\%$ chose 3 hours out of the range of 1-11 hour(s). 10. With regard to the evaluation by school nurses on smoking-prevention program, more than $30\%$ felt that hours of education, education materials, medium of education, interests of other teachers, interests of school authorities, etc. were inadequate or insufficient.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.98-108
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• 1998

In the multimedia tele-medical system the medical informations are stored and managed in multimedia database. Also, multimedia DBMS is essential in order to manage large scale medical informations, and the remote access function is necessary for the distributed processing at all around the hospital. For the multimedia tele-medical information that is composed of image/picture, data, video, and audio, a high-speed telecommunication network is necessary that can provide separated connections for each medical information type with different QoS. The commercial DBMSs are based on the TCP/IP socket API(Application Programming Interface) that does not provide multiple QoS. Also, each commercial DBMS has its own API that is incompatible with other DBMS. In this paper, we propose a multimedia DBMS agent for the remote access of the multimedia database in the tele-medical system. The proposed multimedia DBMS agent is based on the ATM API that can provide high-speed data transfer capability and multiple QoS connections. Also, the proposed multimedia DBMS agent is independent of the commercial DBMS. We explain the functional architecture of the multimedia DBMS agent, implementation technology on the ATM network environment, and the result of performance analysis.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.2
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• pp.18-25
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• 2017

In computer science, an encoding is a standardization of converting information to one format for audio, video or text. Therefore, the encoding information of the data should be known to open and read it and there are algorithms detecting encoder of the data. However, some informations of data could be disappeared by packet loss when transmitted on network, especially, if the data is snatched by packet sniffing or eavesdropping from wireless communications. In this paper, we improve the performance of encoding detection algorithm of 'uchardet' program for multi-byte encoded data with errors based on bit-shift algorithm. To simulate the performance, we generated Korean and Japanese text data with errors that is removed some random bits at random positions. Then the detection algorithm are tested using the data and 'uchardet-bitshift' showed better performance than 'uchardet'. When Korean texts are used, 'uchardet' could detect perfectly with ≤0.005% errors but it showed 0% detection rate with ≥1% errors while 'uchardet-bitshift' detected perfectly with ≤0.05% errors and it showed correct detection cases with ≥1% errors. Japanese texts with errors tend to report falsely as Chinese encoding because Japanese texts include lots of Chinese characters. As a results, we improved encoding detection algorithms by applying bit shift operation.

• The Korean Journal of Archival Studies
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• no.72
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• pp.91-163
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• 2022

The focus of this paper lies on the fact that the 'management' and 'utilization' of audiovisual archives are still not specialized in both the public and the private sectors. The use of online video platforms including 'YouTube' has became common. Accordingly the production and collection of high-definition and high-capacity audiovisual archives has been rapidly increasing. However, it also emphasizes that there are no references or principles in the current Public Records Act and its enforcement rules, public standards, and guidelines. This paper ultimately examines the provisions that are related to audiovisual archives of the current Public Records Act, which needed to be revised and enacted due to the lack of an audiovisual archives management manual of national institutions, public broadcasters, and organizations can refer to. In addition, this study tries to find out what kind of systems and guidelines are used in audiovisual archives management. This paper examines the current state of standardization of audiovisual records of the National Archives. It also analyses the systems and the guidelines methodically for efficient audiovisual record management in the public records management sector. It suggests the new direction of relevant public standards and guidelines through this research. Futhermore, it measures to activate the audiovisual management policy-making functions of the National Archives. The necessity of establishing a Public Audiovisual Archives as an organization was also reviewed in this paper. The Public Audiovisual Archives will collect Public Audio and Videos systematically and comprehensively through the legal deposit system. And it will be operated by the management and the utilization system so that it can be used for public as a collective memory. Finally, it will takes a charge of a professional role in audiovisual record management field, such as technology standardization to safeguard and protect the copyrights through this process.