• School Mathematics
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• v.6 no.1
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• pp.59-90
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• 2004

This study has been established with two purposes. The first one is to development the learning-teaching model for enhancing students' creative proof capacities in the domain of demonstrative geometry as subject content. The second one is to aim at experimentally testing its effectiveness. First, we develop the learning-teaching model for enhancing students' proof capacities. This model is named the generative-convergent model based instruction. It consists of the following components: warming-up activities, generative activities, convergent activities, reflective discussion, other high quality resources etc. Second, to investigate the effects of the generative-convergent model based instruction, 160 8th-grade students are selected and are assigned to experimental and control groups. We focused that the generative-convergent model based instruction would be more effective than the traditional teaching method for improving middle school students' proof-writing capacities and error remediation. In conclusion, the generative-convergent model based instruction would be useful for improving middle grade students' proof-writing capacities. We suggest the following: first, it is required to refine the generative-convergent model for enhancing proof-problem solving capacities; second, it is also required to develop teaching materials in the generative-convergent model based instruction.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.4
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• pp.589-608
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• 2015

The inquiry subject of this paper is the number of convex polygons one can form by attaching the seven pieces of a tangram. This was identified by two mathematical proofs. One is by using Pick's Theorem and the other is 和々草's method, but they are difficult for elementary students because they are part of the middle school curriculum. This paper suggests new methods, by using unit area and the minimum area which can be applied at the elementary level. Development of programs for the mathematically gifted elementary students can be composed of 4 class times to see if they can prove it by using new methods. Five mathematically gifted 5th grade students, who belonged to the gifted class in an elementary school participated in this program. The research results showed that the students can justify the number of convex polygons by attaching edgewise seven pieces of tangrams.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.1015-1020
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• 2003

Among the techniques to protect private information by adopting biometrics, speaker verification is expected to be widely used due to advantages in convenient usage and implementation cost. Speaker verification should achieve a high degree of the reliability in the verification score, the flexibility in speech text usage, and the efficiency in verification system complexity. Continuants have excellent speaker-discriminant power and the modest number of phonemes in the category, and multilayer perceptrons (MLPs) have superior recognition ability and fast operation speed. In consequence, the two provide viable ways for speaker verification system to obtain the above properties. This paper implements a system to which continuants and MLPs are applied, and evaluates the system using a Korean speech database. The results of the experiment prove that continuants and MLPs enable the system to acquire the three properties.

• The Journal of the Acoustical Society of Korea
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• v.22 no.5
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• pp.360-366
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• 2003

Although multilayer perceptrons (MLPs) present several advantages against other pattern recognition methods, MLP-based speaker verification systems suffer from slow enrollment speed caused by many background speakers to achieve a low verification error. To solve this problem, the quantitative discriminative cohort speakers (QnDCS) method, by introducing the cohort speakers method into the systems, reduced the number of background speakers required to enroll speakers. Although the QnDCS achieved the goal to some extent, the improvement rate for the enrolling speed was still unsatisfactory. To improve the enrolling speed, this paper proposes the qualitative DCS (QlDCS) by introducing a qualitative criterion to select less background speakers. An experiment for both methods is conducted to use the speaker verification system based on MLPs and continuants, and speech database. The results of the experiment show that the proposed QlDCS method enrolls speakers in two times shorter time than the QnDCS does over the online error backpropagation(EBP) method.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.367-371
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• 2010

가뭄 발생원인은 기후학적인 인자(온도, 바람, 상대습도 등)들과 밀접한 관계를 갖고 있으나, 가장 큰 원인은 강수부족이라고 말할 수 있다. 따라서 가뭄은 정상수준 이하의 강수 상황이 연속적으로 발생하여 나타나며, 설정된 절단수준에 대해 가뭄의 지속기간, 심도, 발생간격 등을 정의한 후 이에 대한 시계열 분석을 수행하여 가뭄의 특성을 분석한다. 본 연구에서는 가뭄 절단수준의 변화에 따른 한반도 내 가뭄의 특성분석을 위하여 하나의 절단수준으로 고정된 경우의 가뭄특성과 각 년도 월별 특성을 고려하여 절단수준이 지속적으로 변화하는 경우로 구분하여, 가뭄특성의 변화를 분석하였다. 또한 위 두 가지 경우에 대해 각각 가뭄해소 여부를 판단하여 총 4가지 경우에 따른 가뭄 특성을 분석하였다. 가뭄 절단수준의 변화 및 가뭄 해소여부에 따른 한반도 내 가뭄 특성을 분석하기 위해, 가뭄의 지속기간, 심도의 기초통계량 등을 산정하여 비교 분석하였다. 본 연구는 한반도 내의 가뭄특성을 보다 정확하게 해석하기 위해서는 다양한 가뭄정의에 따라 가뭄 해석결과가 나타내는 상대적 차이를 비교할 필요성이 있음을 증명하였다.

• School Mathematics
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• v.13 no.3
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• pp.501-524
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• 2011

The purpose of this study was to develop teaching-learning materials for informal activities geared toward teaching the nature and structure of proof, to make a case analysis of the application of the developed instructional materials to students in an elementary gifted class, to discuss the feasibility of proof education for gifted elementary students and to give some suggestions on that proof education. It's ultimately meant to help improve the proof abilities of elementary gifted students. After the characteristics of the eight selected gifted elementary students were analyzed, instructional materials of nine sessions were developed to let them learn about the nature and structure of proof by utilizing informal activities. And then they took a lesson two times by using the instructional materials, and how they responded to that education was checked. An analysis framework was produced to assess how they solved the given proof problems, and another analysis framework was made to evaluate their understanding of the structure and nature of proof. In order to see whether they showed any improvement in proof abilities, their proof abilities and proof attitude were tested after they took lessons. And then they were asked to write how they felt, and there appeared seven kinds of significant responses when their writings were analyzed. Their responses proved the possibility of proof education for gifted elementary students, and seven suggestions were given on that education.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.555-568
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• 2018

This study has expanded the existing studies on the characteristics of consumers using the personal level of cultural dimensions and self-construal. As Korean are becoming more individualistic and independent, we have focused on consumer independence in self-construal. The purpose of this study was to investigate the effects of consumer independence on consumers' attitudes and purchase intention toward consensus claim in ads. We hypothesized that individuals with higher in independence are more likely to show negative attitudes and the purchase intention towards the ads focused on consensus claim. Two experiments revealed that consumers higher in independence, depicting consensus claim in ads reduces consumers' attitudes and purchase intention. Based on the results, we suggest that for individuals higher in independence, consensus claims in product advertisement are less effective advertising strategy which ultimately lower consumers' purchase intentions. Important theoretical and practical implications are discussed.

• The Korean Journal of Air & Space Law and Policy
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• v.26 no.1
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• pp.31-63
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• 2011

Since Korea has invested only on developing an aircraft, it is true that Korea has neglected detailed standards and procedures about certification activities including essential safety procedures. Most developed countries have implemented mandatory airworthiness system by legislating it for operational safety of aircraft based on ICAO Annex 8, and the U.S. Department of Defense and the FAA's Airworthiness system have been adapted it to the realities of their circumstance. Therefore, Airworthiness system that can guarantee the safety of the aircraft at international level is necessary to enhance flight safety and to create export opportunities of an aircraft as a country which can develop an aircraft by itself To achieve this, a study on the improvement of aircraft airworthiness was carried out by analyzing the problem of domestic airworthiness system and by reflecting international best practices on the establishment of a system for improved Airworthiness.

• The Journal of shipping and logistics
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• v.35 no.2
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• pp.245-264
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• 2019

With the first agrement in 2004, Korea(ROK) has been one of the most active countries participating in FTA. Companies should meet some requirements to use preferential tariff benefits of FTA. For example, it is required for firms to fulfil the origin criteria and direct transportation principles. This study is designed to provide important factors determining reliability of FTA Origin Certificate. In specific, characteries of firm(trade experience, professional expertise), country (FTA participation, economic development) and product(processing level, value pricing) are investigated as determinants of how trust FTA origin certificate. According to the theoretical foundation and previous studies, this study made 6 hypotheses. SEM(Structural Equation Modeling) was used to test empirically the hypothesized relationships among variables. The empirical findings show that trade experience, professional expertise and FTA participation are important determinants. In other words, firms can trust more FTA Origin Certificate by trading partners with more trading experiences and professional expertises located in countries where participate actively in FTA.

• 월간산업보건
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• s.258
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• pp.11-14
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• 2009

살균제인 pentachloronitrobenzene(PCNB)의 직업적 노출을 위한 TLV-TWA를 0.5 mg/$m^3$으로 권고하였다. 이 수준은 간에 영향을 미치는 것을 최소화하기 위한 수준이다 피부자극과 피부 흡수에 관한 것은 증명되지 않았다. PCNB에 대한 발암가능성을 흰쥐와 생쥐를 대상으로 생물학적 검정을 한 결과, 생쥐에서 양성이었다. 이러한 결과는 생물학적 검정에 사용한 PCNB가 공업용이었고 불순물로 포함된 hexachlorobenzene에 의해 암이 유발된 것으로 확인되었다. 따라서 FCNB 물질은 발암성 유발 인자(A4;Not Classifiable as a Human Carcinogen)로 권고하였다. PCNB의 Skin, SEN notation, TLV-STEL에 관한 정보는 충분한 데이터가 확보되지 않아 제공되지 못하고 있다.