• Journal for History of Mathematics
• /
• v.17 no.3
• /
• pp.13-22
• /
• 2004

In this paper, we consider two conjectures, the Bieberbach Conjecture that was proved true and the Lu Qi-Keng Conjecture that was proved not true. We inspect them historically and introduce the interesting results. From them we find that the deep theory of mathematics comes from continuous conjectures.

• The Journal of Korean Association of Computer Education
• /
• v.23 no.1
• /
• pp.29-36
• /
• 2020

Various items were used as evaluation tools that identify the student's abilities accurately to confirm the completion of learning. Among them, the multiple choice item has the advantages of high objectivity and reliability in scoring, but it cannot remove the factor of guessing. In this paper, the multiple choice items are classified into two types according to the relationship between the questionnaire and the choices. One is the type used in the classical test theory with the probability of guessing 1/k for k choices and the other is the novel proposed type which introduces the concept of partial knowledge. In the proposed type, the probability of guessing when the number of knowledge i is (i+1)/k for k choices. Based on the assumptions of the previous theories about multiple choice items, we derive the guessing parameter about the proposed type. And we analyzed the effect of the guess on the correct answer in the existing type and the proposed type. This shows that the proposed type has more question guessing than the existing type.

• Journal for History of Mathematics
• /
• v.21 no.3
• /
• pp.113-126
• /
• 2008

This work is devoted to study about the abc conjecture: how it works in the development of the proof of Fermat's last theorem and more generally in the diophantine equation theory. And it is also studied the application of the abc conjecture to the iteration of polynomials.

• School Mathematics
• /
• v.13 no.1
• /
• pp.107-125
• /
• 2011

In this paper, we investigated how the GSP environments impact students' conjecturing of geometric properties. And we wanted to draw some implication in teaching and learning geometry in dynamic geometric environments. As results, we conclude that when students were given the problem situations which almost has no condition, they were not successful, and rather when the problem situations had appropriate conditions students were able to generate many conditions which were not given in the original problem situations, and consequently they were more successful in conjecturing geometric properties. And the geometric properties conjectured in GSP environments are more complex and difficult to prove than those in paper and pencil environments. Also the function of moving screen with 'Alt' key is frequently used in conjecturing geometric properties with functions of measurement and calculation of GSP. And students felt happier when they discovered geometric properties than when they could prove geometric properties.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.06a
• /
• pp.287-289
• /
• 2014

선박의 선위 추측(DR, Dead Reckoning)은 수신되거나 측정된 위치 데이터와 속력, 침로 데이터만을 반영하여 계산하므로 대양의 항해나 연근해의 해역에서는 유효할 수 있으나 침로의 변경과 선속의 변화가 잦은 항계 내의 조선에 있어서는 적용이 어렵다는 문제점이 있다. 본 논문에서 제안하는 선박의 추측위치(DRP, Dead Reckoning Position)는 선박의 운항 패턴에 따라 항계 내의 항적 데이터를 수집하고, 수신된 위치 데이터와 속력, 침로 데이터를 점장위도항법(Mercator Sailing)을 통하여 계획항로(Planned Route)의 각 변침점(WP, Waypoint)간 침로(Course)와 항정(Ship's Passage)에 반영하였다. 제안된 추측위치 산출방법을 통하여 항계 내의 조선과정에서 계획항로를 선박의 추측위치와 결합하여 특정 시간 후의 상황패턴을 미리 예측하고 관제사의 의사결정에 기여하고자 한다.

• Journal of Educational Research in Mathematics
• /
• v.27 no.3
• /
• pp.491-510
• /
• 2017

This study analyzes on conjecturing tasks in elementary mathematics textbook. We adopted Peircean semiotic perspective and variation theory to analyze conjecturing tasks in elementary mathematics textbook. We specifically analyzed mathematical tasks designed to support students' inquiries into definitions and properties of quardrilaterals. As a result, we found that conjecturing tasks in textbooks do not focus on supporting students' diagrammatic reasoning and inductive verification on provisional abductions. These tasks were mainly designed to support students' conjecturing on commonalities of mathematical objects rather than differences between objects.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.1
• /
• pp.99-108
• /
• 2014

Recently, the interest in autonomous vehicle which is an aggregate of the automotive control technology is increasing. In particular, researches on the self-localization technology that is directly connected with stable driving of autonomous vehicle have been performed. Various dead reckoning technologies which are solutions for resolving the limitation of GPS have been introduced. However, the conventional dead reckoning technologies have two disadvantages to apply on the autonomous vehicle. First one is that the expensive sensors must be equipped additionally. The other one is that the accuracy of self-localization decreases caused by wheel slip when the vehicle's motion changed rapidly. Based on this background, in this paper, the wheel speed sensor which is equipped on most of vehicles was used and the dead reckoning algorithm considering wheel slip ratio was developed for autonomous vehicle. Finally, in order to evaluate the performance of developed algorithm, the various simulation were conducted and the results were compared with the conventional algorithm.

• The KIPS Transactions:PartA
• /
• v.15A no.4
• /
• pp.217-226
• /
• 2008

Branch prediction accuracy is critical for system performance in modern microprocessor architectures. The use of speculative update branch history provides substantial accuracy improvement in branch prediction. However, speculative update branch history is the information about uncommitted branch instruction and thus it may hurts program correctness, in case of miss-speculative execution. Therefore, speculative update branch history requires suitable recovery mechanisms to provide program correctness as well as performance improvement. In this paper, we propose recovery logics for speculative update branch history. The proposed solutions are recovery logics for both global history and local history. In simulation results, our solution provides performance improvement up to 5.64%. In addition, it guarantees the program correctness and almost 90% of additional hardware overhead is reduced, compared to previous works.

• Journal of Korea Entertainment Industry Association
• /
• v.15 no.5
• /
• pp.141-151
• /
• 2021

This study analyzed the meaning and functions of '-(으)ㄹ 것 같다' and '-나 보다' among the various semantic functions depending on the situation, and discussed ways to train speculative expressions more efficiently by expanding them from traditional teaching methods through visualizations applied visual thinking at real Korean language education. The speculative representation, which is the subject of this study, represents the speaker's speculation about something or situation, with slight differences in meaning depending on the basis of the speculation and the subject of the speculation. We propose a training method that can enhance the diversification and efficiency of teaching-learning through visualization of information or knowledge, speculative representations that exhibit fine semantic differences in various situations. Utilizing visual thinking in language education can simplify and provide language information through visualization of language knowledge, and learners can be efficient at organizing and organizing language knowledge. It also has the advantage of long-term memory of language information through visualization of language knowledge. Attempts of various educational methods that can be applied at the Korean language education site can contribute to establishing a more systematic and efficient education method, which is meaningful in that the visual thinking proposed in this study can give interest and efficiency to international students.

• Phonetics and Speech Sciences
• /
• v.14 no.4
• /
• pp.1-10
• /
• 2022

The Korean polysemic ending '-(eu)lgeol' can has two different meanings, 'guess' and 'regret'. These are expressed by different boundary-tone types: a rising tone for guess, a falling one for regret. Therefore the sentence-final boundary-tone type is the most salient prosodic feature. However, besides tone type, the pitch difference between the final and penultimate syllables of '-(eu)lgeol' can also affect semantic discrimination. To investigate this aspect, we conducted a perception test using two sentences that were morphologically and syntactically identical. These two sentences were spoken using different boundary-tone types by a Korean native speaker. From these two sentences, the experimental stimuli were generated by artificially raising or lowering the pitch of the boundary syllable by 1Qt while fixing the pitch of the penultimate syllable and boundary-tone type. Thirty Korean native speakers participated in three levels of perceptual test, in which they were asked to mark whether the experimental sentences they listened to were perceived as guess or regret. The results revealed that regardless of boundary-tone types, the larger the pitch difference between the final and penultimate syllable in the positive direction, the more likely it is perceived as guess, and the smaller the pitch difference in the negative direction, the more likely it is perceived as regret.