• Journal of the Korean School Mathematics Society
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• v.10 no.2
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• pp.221-235
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• 2007

Open problems can provide experiences for students to yield originative and various products in their level, because it is open with respect to its departure situation, goal situation, or solving method. Teachers need to pose and utilize open problems in forms of solution-finding or proving problems. For this we first have to specify which resource and method to use by concrete examples. In this article, we exemplify a method and procedure of posing an open problem by the two cases in which we pose open problems by reorganizing given closed problems. And we analyze students' responses for the two posed open problems. On the basis of these, we reflect implications for mathematical education of open problems.

• Journal of Science Education
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• v.39 no.2
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• pp.267-277
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• 2015

This study explored elementary school teachers' perspectives on science inquiry teaching. First, an open-ended questionnaire was administered to elicit teachers' experiences of their approach to inquiry teaching. These self-reported approaches revealed three conceptions of teaching for inquiry learning in science: 'science process skills-centered' category focused on observing, classifying, measuring, and fair testing; 'generating scientific questions' category focused on students' question-generating; and 'illustrate concept and/or content' category focused on science content demonstration by making use of experimental procedures to obtain expected results. Second, teachers were asked to place 18 activity cards either close to or further from an 'inquiry-based science classroom' card. The relative distances from the activity card to the central classroom card were measured. The teachers perceived that students' activity of 'designing and implementing appropriate procedures' was the most important in supporting an inquiry-based science classroom. Understanding teachers' views has implications for both the enactment of inquiry teaching in the classroom as well as the uptake of new teaching behaviors during professional development.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.819-824
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• 2012

In this paper, mandatory minimum requirements for certification of officers in charge of a navigational watch on ship by international convention on STCW (standards of training certification and watchkeeping for seafarers) were investigated. The training education and evaluation systems for navigational competence of Korean navy were compared and analyzed. As a result, we have confirmed that junior naval officers from Korean midshipmen had the navigational competence based on the STCW convention by analyzing the courses of Korea naval academy, midshipmen life, training exercise systems, and so on. OCS and NROTC provided a curriculum that did not quite meet the standard of the STCW convention. However, it was sufficient for nurturing basic abilities for navigation safety.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.37-46
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• 2007

The authentication in WSN(Wireless Sensor Network) usually means the entity authentication, but owing to the data centric nature of sensor network, much more importance must be put on the authentication(or attestation) for code of sensor nodes. The naive approach to the attestation is for the verifier to compare the previously known memory contents of the target node with the actual memory contents in the target node, but it has a significant drawback. In this paper, we show what the drawback is and propose a countermeasure. This scheme can verify the whole memory space of the target node and provides extremely low probability of malicious code's concealment without depending on accurate timing information unlike SWATT. We provide two modes of this verification method: BS-to-node and node-to-node. The performance estimation in various environments is shown.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.107-122
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• 1997

Most of the currently used electronic mail system has the threat of security such as illegal leak of message, forgery, uncertain identity, denial of sending and receiving, and so forth. The security for this system is not satisfied yet, thus we explore these problems. In this thesis, we implement the security services for internet mail system which cover the weakness for traditional mail system. This system provides not only security services which PEM and PGP provides (i.e message confidentiality, message integrity, originator authentication, non-repudiation of origin), but also message replay prevention. and non-denial of recipient using certification of contents. In addition, this system increases security of the digital signature by signing with signature block formatting on the creation of it. And it increases security of the digital enveloping by encrypting with encryption block formatting of message encryption key.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.678-686
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• 2021

A smiling face usually has a positive effect on interpersonal relationships by delivering a warm impression. However, the stereotype content model and compensation effect between warmth and competence suggested that warmth perceptions caused by a smiling face could influence competence perceptions negatively. This study examined the negative impact of the advertising endorser's smile on purchase intention in an expensive product category by adopting the self-construal level. The study results showed that consumers with independent-self construal (vs. interdependent self-construal) showed a lower purchase intention when exposed to an ad containing an endorser's smile. In comparison, consumers with interdependent-self construal (vs. independent self-construal) showed a lower purchase intention when exposed to an ad without an endorser's smile. Thus, this study demonstrated a moderating role of self-construal in the relationship between advertising endorser's smile and purchase intention. These findings provide valuable theoretical and practical implications for effective advertising strategies in the expensive product category.

• SUVANNABHUMI
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• v.2 no.1
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• pp.95-110
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• 2010

Poem plays an important role in Ca trù. Many music researchers say that singing Ca trù is singing poem. Of 46 tunes of Ca trù, there are more than 10 tunes expressed in available poems or styles of poetry; for example: in the tune Tỳ bà, the performer could sing Tỳ bà hành by Bạch Cư Dị being converted into seven-seven-six-eight-word-meter; in the reciting poem tunes, just reciting 5 Thien thai poems by Tào Đường or 3 Thanh Bình tune poems by Lý Bạch; in the reciting poetic essay (phú), reciting Tien Xich Bich and Hau Xich Bich by Tô Đông Pha. Others like bắc phản, cung bắc sometimes used six-eight word meters. Structurally, those are available for familiar types and beyond the scope of particular creativity because they do not originate from Ca trù's activity environment like recitative. Recitative is the main tune of Ca trù and has become an independent poem type. In terms of literature, recitative has a particular form structure and special type content. Unlike other tunes of Ca trù that only stop at some fixed works, recitative has increased to thousands of works in quantity and has been composed for many centuries. For those reasons, we confined ourselves the research to the creation which is the most typical of Ca tru: The recitative.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.75-82
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• 2010

The paper proposed CBIRS/EFI with contents based search technique using edge feature information of the object from image information of the object which is uncertain. In order to search specially efficiently case of partial image information of the object, we used the search technique which extracts outline information and color information in feature information of object. In order to experiment this, we extracted side edge feature information of the vehicle for feature information of the object after capture the car image of the underground garage. This is the system which applies a contents base search by the result which analyzes the image which extracts a feature, an original image to search and a last similar measurement result. This system compared in FE-CBIRS systems which are an existing feature extraction contents base image retrieval system and the function which improves the accuracy and an effectiveness of search rate was complemented. The performance appraisal of CBIRS/EFI systems applied edge extraction feature information and color information of the cars. And we compared a color feature search time, a shape characteristic search time and a search rate from the process which searches area feature information. We extracted the case 91.84% of car edge feature extraction rate. And a average search time of CBIRS/EFI is showing a difference of average 0.4-0.9 seconds than FE-CBIRS from vehicle. color search time, shape characteristic search time and similar search time. So, it was proven with the fact that is excellent.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.12
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• pp.708-713
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• 2003

For many years clustered heterogeneous web server architecture has been formed on the internet because the explosive internet services and the various quality of requests. The critical point in cluster environment is the mapping schemes of request to server. and recently this is the main issue of internet architecture. The topic of previous mapping methods is to assign equal loads to servers in cluster using the number of requests. But recent growth of various services makes it hard to depend on simple load balancing to satisfy appropriate latency. So mapping based on requested content to decrease response time and to increase cache hit rates on entire servers - so called “content-based” mapping is highly valuated on the internet recently. This paper proposes Prioritized Highest Random Weight mapping(PHRW mapping) that improves content-based mapping to properly fit in the heterogeneous environment. This mapping scheme that assigns requests to the servers with priority, is very effective on heterogeneous web server cluster, especially effective on decreasing latency of reactive data service which has limit on latency. This paper have proved through algorithm and simulation that proposed PHRW mapping show higher-performance by decrease in latency.

• Journal for History of Mathematics
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• v.21 no.2
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• pp.55-70
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• 2008

This study is about the Data which is one of Euclid's writing. It dealt with the organization of contents, formal system and mathematical meaning. First, we investigated the organization of contents of the Data. Second, on the basis of this investigation, we analyzed the formal system of the Data. It contains the analysis of described method of definition, proposition, proof and the meaning of 'given'. Third, we explored the mathematical meaning of the Data which can be classified as algebraic point of view, geometric point of view and the opposite point of view to 'The Elements'.