초등학생의 계절별 별자리 학습에서 SBF 질문이 개념성취와 시선이동에 미치는 영향

김재선,양일호,임성만 대한지구과학교육학회 2023 대한지구과학교육학회지 Vol.16 No.2

이 연구 목적은 시스템 사고가 요구되는 계절별 별 자리 학습에서 SBF 질문을 제시한 경우, 초등학생의 개념성취 수준과 시선이동에 미치는 영향을 분석하는 것이다. 본 연구에서는 SBF 질문의 효과를 알아보기 위해 연구집단과 비교집단으로 나누고 질문 유형을 달 리한 과학 텍스트를 제시하여 초등학교 6학년 학습자 의 개념성취 수준 및 시선이동 차이를 분석하였다. 개 념성취 수준을 분석하기 위해 집단 내·집단 간 사전· 사후 검사를 실시하였으며, 시선이동 차이를 분석하기 위해 Eye-tracker를 활용하여 학습자의 시선을 추적하 였다. 연구 참여자는 연구 참여 동의서를 통해 자발적 으로 연구 참여 의사를 밝힌 초등학교 6학년 학생 36 명이다(연구집단 18명, 비교집단 18명). 본 연구를 위 해 연구 참여자는 2015 개정 교육과정에서 제시한 계 절별 별자리와 관련된 학습 내용 전까지만 학습한 상 태로 연구에 참여하였다. 자료 분석은 개발한 개념 검 사지의 사전·사후 검사 결과와 계절별 별자리와 관련 된 과학 텍스트를 학습할 때의 시선이동 자료를 정량 적으로 분석하였다. 연구 결과 첫째, 계절별 별자리 학 습에서 SBF 질문은 유효한 학습 전략이었다. 학습자에 게 구조(Structure)-작용(Behavior)-기능(Function)과 관 련된 질문을 순차적이고 구체적으로 제시하였을 때, 일반적인 질문보다 더 높은 학습효과를 나타내었다. 즉 SBF 질문은 집단 간 사전·사후 개념 검사에서 통계 적으로 유의한 차이(p<0.05)를 보였으며, 집단 내 사전·사후 개념 검사에서 통계적으로 유의한 차이(p<0.001)를 보였다. 둘째, SBF 질문은 선개념이 높지 않은 학습자에게 개념성취에 도움이 되는 영역을 학습하도록 유도하여 학습자의 학습에 긍정적인 영향을 주었다. 즉,우주기반 관점의 시각 자료와 함께 SBF 질문을 제시하였을 때, 교과서의 일반적인 질문을 제시한 경우보다 학습자의 총 시선고정 수에서 유의미한 차이(p<0.01)를 보임을 시선이동 분석 결과를 토대로 확인하였으며, SBF 질문으로 학습한 학습자의 개념성취 수준이 향상됨을 정량적으로 확인하였다. 이는 SBF 질문이 시각 자료가 함께 제시된 과학 텍스트 학습 과정에서 능동적인 학습을 촉진한다는 실증적인 증거이다. 반면, 과학적 선개념을 많이 가지고 있는 학습자에게는 SBF 질문의 효과보다 학습자 자신이 가지고 있는선개념이 견고한 핵으로 작용하여 탐구의 효과가 크지않았다. 본 연구는 계절별 별자리 학습 과정에서 SBF질문의 효과를 사전·사후 검사와 시선이동 분석을 통해 정량적인 자료로 제공한다는 점에서 기존 계절별별자리 학습 연구와 차별성이 있으며, 초등학생의 계절별 별자리 학습과 관련된 지도방안에 도움을 줄 수있다. The purpose of this study was to study to the effect of presenting SBF questions on the level of conceptual achievement and eye movement of elementary students in seasonal constellation learning that requires systems thinking. In this study, the effectiveness of SBF questions was divided into experimental groups and comparison groups, and scientific texts with different question types were presented to analyze the level of conceptual achievement and differences in eye movement of sixth-grade elementary students. Data analysis quantitatively analyzed the pre- and post-test results of the developed concept test paper and the eye movement data when learning scientific texts related to seasonal constellations. As a result of the study, first, the SBF question was a valid learning strategy for learning seasonal constellations. The SBF question showed a statistically significant difference (p<0.05) in the pre- and post-test between groups, and a statistically significant difference (p<0.001) in the pre- and post-test within the group. Second, SBF questions had a positive effect on students' learning by inducing learners with low preconceptions to area of interest that help them achieve concepts. In other words, when presenting SBF questions with visual data from a space-based perspective, it was confirmed based on the results of eye movement analysis that there was a significant difference in total fixation count (p<0.01) of learners. On the other hand, for learners with high scientific preconceptions, the effect of exploration was not significant because the preconceptions of the learners themselves acted as a hard core rather than the effect of SBF questions. This study is different from existing seasonal constellation learning studies in that it provides quantitative data through pre- and post-test and eye movement analysis in the seasonal constellation learning process, and can help elementary students learn seasonal constellations.

개선된 간단한 경계선 추적자 알고리즘

정철호(Cheolho Cheong),한탁돈(Tack-Don Han) 한국정보과학회 2006 정보과학회논문지 : 소프트웨어 및 응용 Vol.33 No.4

간단한 경계선 추적자 알고리즘(SBF: Simple Boundary Follower)은 영상의 인식과 표현을 위하여 사용되는 경계선 추적 알고리즘 중에서 널리 사용되는 것이다. SBF는 주로 이진화된 영상에서 물체의 경계선을 추적할 때 매우 간단하면서도 효율적인 성능을 제공한다. 그러나 추적자의 위치와 방향조건에 따라 인너코너(inner corner)와 인너-아우터 코너(inner-outer corner)의 일부 영상을 추적하지 못하는 비일관성(inconsistency)을 가지고 있고, 경계선 이외의 픽셀들에 대한 부가적인 이동연산을 요구한다는 단점이 있다. 이러한 제약성들 중 인너-아우터 코너의 비일관성을 해결하기 위하여 수정된 간단한 경계선 추적자 알고리즘(MSBF: Modified Simple Boundary Follower)이 연구되었지만 여전히 인너코너 추적 비일관성과 부가 연산 필요성에 대한 해결책은 제시되지 않았다. 본 논문에서는 이를 개선하기 위하여 비일관성이 일어나지 않도록 처리하고, 경계선 주위 픽셀에 대한 이동 연산을 줄일 수 있는 개선된 간단한 경계선 추적자 알고리즘(ISBF: Improved Simple Boundary Follower)을 제안하였다. 또한 경계선상의 픽셀들의 배치와 이동 경로 방식에 대해 분류를 함으로써 세 가지 알고리즘의 연산복잡도를 계산하였다. 제안된 알고리즘은 MSBF에 비하여 연산량이 감소하였고, 비일관성의 문제가 없는 것으로 분석되었다. The SBF (Simple Boundary Follower) is a boundary-following algorithm, and is used mainly for image recognition and presentation. The SBF is very popular because of its simplicity and efficiency in tracing the boundary of an object from an acquired binary image; however, it does have two drawbacks. First, the SBF cannot consistently process inner or inner-outer corners according to the follower'sposition and direction. Second, the SBF requires movement operations for the non-boundary pixels that are connected to boundary pixels. The MSBF (Modified Simple Boundary Follower) has a diagonal detour step for preventing inner-outer corner inconsistency, but is still inconsistent with inner-corners and still requires extra movement operations on non-boundary pixels. In this paper, we propose the ISBF (Improved Simple Boundary Follower), which solves the inconsistencies and reduces the extra operations. In addition, we have classified the tour maps by paths from a current boundary pixel to the next boundary pixel and have analyzed SBF, MSBF, and ISBF. We have determined that the ISBF has no inconsistency issues and reduces the overall number of operations.

NaOH처리와 SBF침적에 따른 CP-Ti, Ti-6Al-4V 및 ECAP-Ti의 표면 아파타이트 성장

오석진,류재경,이승우,김윤종,한만소,김창규,Oh Seok-Jin,Ruy Jae-Gyeoung,Lee Seung-Woo,Kim Yun-Jong,Han Man-So,Kim Chang-Hyu 한국재료학회 2004 한국재료학회지 Vol.14 No.12

Even though Ti-6Al-4V has gained popularity as an implant material, the possible dissolution of Al and V ions in body fluids remains a matter of concern. Though commercially pure Ti (Cp-Ti) overcomes this problem, the mechanical strength of pure titanium remains very low. Thus, in this experiment Cp-Ti was processed by Equal channel angular processing (ECAP), in order to increase the mechanical strength. The biocompatibility of ECAP-Ti, Cp-Ti and Ti-6Al-4V was examined by the apatite formation on each sample surface, after treating the surface with 5M NaOH and soaking in Simulated body fluids (SBF). Initially, the samples were mechanically polished on silicone carbide paper (#2000). The polished samples were treated with 5M NaOH solution at $60^{\circ}C$ for 24 hours. The NaOH treated samples were washed gently with distill water and dried at $40^{\circ}C$ for 1 day. The dried samples were heat treated in air at $600^{\circ}C$ for 1 hour. The surface morphology of these samples were studied using SEM and XRD. The SEM studies showed network of pores in all samples. The XRD showed oxide layer formation on Cp-Ti and Ti-6Al-4V. samples. However the oxide layer in ECAP-Ti was not substantial. These samples were immersed in SBF, kept at $36.5^{\circ}C$ for seven days period. At the end of 7 days, the apatite formation was confirmed only on Cp-Ti and was not observed in Ti-6Al-4V and ECAP-Ti. These observations of apatite formation relate to the fact that Cp-Ti showed greater oxide layer than other samples. The apatite examined was confirmed as tricalcium phosphate (TCP) using EDS and XRD.

Effect of Collagen Treatment on Bioactivity of Ti-6Al-7Nb and Ti-6Al-4V Alloys

김태호,이갑호,홍순익 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.10

Biomimetic apatite formation and deposition behaviors of Ti-6Al-7Nb and Ti-6Al-4V plates in simulated body fluids (SBF) under various conditions were examined. In case of regular samples without collagen treatments the weight gain due to apatite precipitation on the surface in Ti-6Al-4V was found to be higher than in Ti-6Al-7Nb. In case of collagen-coated samples, the weight gain in Ti- 6Al-4V continued to be higher than in Ti-6Al-7Nb, but the difference between the two became smaller. Both Ti-6Al-7Nb and Ti-6Al- 4V samples with collagen coating exhibited an appreciable increase of weight gain, which may be caused by the interaction between collagen and Ca +2 ions. The weight gain was found to be not much affected by the addition of collagen to SBF. The ill-defined granular structure in the presence of collagen can be associated with the increasing volume fraction of amorphous calcium phosphate. Biomimetic apatite formation and deposition behaviors of Ti-6Al-7Nb and Ti-6Al-4V plates in simulated body fluids (SBF) under various conditions were examined. In case of regular samples without collagen treatments the weight gain due to apatite precipitation on the surface in Ti-6Al-4V was found to be higher than in Ti-6Al-7Nb. In case of collagen-coated samples, the weight gain in Ti- 6Al-4V continued to be higher than in Ti-6Al-7Nb, but the difference between the two became smaller. Both Ti-6Al-7Nb and Ti-6Al- 4V samples with collagen coating exhibited an appreciable increase of weight gain, which may be caused by the interaction between collagen and Ca +2 ions. The weight gain was found to be not much affected by the addition of collagen to SBF. The ill-defined granular structure in the presence of collagen can be associated with the increasing volume fraction of amorphous calcium phosphate.

Bone-like apatite formation on manganese-hydroxyapatite coating formed on Ti-6Al-4V alloy by plasma electrolytic oxidation

Kang, Jung-In,Son, Mee-Kyoung,Choe, Han-Cheol,Brantley, William A Elsevier S.A. 2016 Thin Solid Films Vol.620 No.-

<P><B>Abstract</B></P> <P>In this study, bone-like apatite formation on manganese-hydroxyapatite (Mn-HA) coatings formed on Ti-6Al-4V by plasma electrolytic oxidation (PEO) has been investigated by several techniques. Ti-6Al-4V ELI disks were used as substrates for PEO treatment. Test specimens were used as anodes, and a Pt rod was used as the cathode in an electrolytic solution containing Mn. The applied voltage was 280V, and the deposition time was 3min. To examine the bioactivity, the PEO films formed on Ti-6Al-4V were immersed in SBF for 12h. The PEO films and the Ti-6Al-4V surface after immersion in SBF were characterized by a thin-film X-ray diffractometer, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy.</P> <P>The PEO surface presented large and irregular pores, and the number of pores increased as the Mn content increased. For the PEO-treated samples, anatase peaks were detected by X-ray diffraction, and the HA peak intensity increased as the Mn content increased. The Ca/P ratio decreased, whereas the (Ca+Mn)/P ratio increased, as the Mn content increased. The coatings without Mn on the micropores had a small granular shape, and the pores were covered with HA after the immersion in SBF. As the Mn concentration increased, all Mn-HA coating surfaces became more dense, and microcracks appeared on the coating surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bone-like apatite formation on the Mn-HA coated Ti-6Al-4V by plasma electrolytic oxidation was investigated. </LI> <LI> The number of large pores with an irregular shape, increased as the Mn content in the coating increased. </LI> <LI> The Ca/P ratio in the coating decreased, whereas the (Ca+Mn)/P ratio increased, as the Mn content increased. </LI> <LI> As the Mn concentration increased, all surfaces become denser, and microcracks were evident on the coated surface. </LI> </UL> </P>

PLGA 필름 표면에 조사된 감마선이 인산칼슘의 침전에미치는 영향평가

조선영,신영민,김용수,박종석,권희정,노영창,임윤묵 한국방사선산업학회 2012 방사선산업학회지 Vol.6 No.1

Gamma-ray irradiation process is very useful to modify the surface of the polymericsubstrates. In this study, we prepared gamma-ray irradiated synthetic biodegradable polymerfilms, and investigated the deposition behaviors of calcium phosphate on them by immersingsimulated body fluids (SBF). The calcium phosphate was successfully coated on the PLGA filmsafter immersing in the 5× SBF. The amounts of deposited calcium phosphate on the film increasedas gamma-ray irradiation doses and immersing time increased, in which nuclear formation ofcalcium phosphate on the films may be affected or accelerated by radiation exposure. Therefore,gamma-ray irradiation dependent surface modification can be useful in bone tissue engineering.

입자크기를 달리한 Cp-Ti의 미세구조 관찰 및 SBF하에서의 부식거동

이승우,김윤종,류재경,박중근,김원수,김택남,Lee Seung-Woo,Kim Yun-Jong,Ruy Jae-Gyeoung,Park Joong-Keun,Kim Won-Soo,Kim Taik-Nam 한국재료학회 2005 한국재료학회지 Vol.15 No.9

Titanium and Titanium alloys are widely used as an orthopedic and dental implant material because of their excellent biocompatibility and mechanical strength. In this study, ECAP Cp-Ti and Cp-Ti were heat treated for different annealing time of 30 min, 90 min and 3 hours. The grain size for each condition was studied. The micro-Vicker hardness test was carried out f3r each different heat treated samples. The micro-Vicker hardness test for ECAP Cp-Ti, Cp-Ti and Cp-Ti (3hr) revealed hardness values of 239.5, 182 and 144 Hv, respectively. The grain size was increased from approximately $70{\mu}m\;to\;300{\mu}m$ with the increase in heat treatment time from 30 min to 3 hours. The heat treated samples were tested for their biocompatibility in simulated body fluid (SBF) and corrosion rates was determined using Polarization Curve test (PCT). The PCT results showed Cp-Ti with comparatively high corrosion potential of -0.18 V and corresponding corrosion current of $2\times10^{-6}$ A, while the corrosion rate in ECAP Cp-Ti and Cp-Ti (30 min annealed) showed very similar results of corrosion potential about -0.47 V with corresponding corrosion current of $7\times10^{-8}$ A.

세 가지 용액에 의한 기혼합형 MTA의 기계 및 물리·화학적 특성 연구

강태윤,최지원,김광만,권재성 대한치과재료학회 2021 대한치과재료학회지 Vol.48 No.4

The study aims to analyze the compressive strength, pH, and surface properties of mineral trioxide aggregates (MTA), which can be used as a pulp capping and root canal filling material. The tests were performed after immersing premixed types of MTA for seven days into three different solutions: simulated body fluid (SBF), saline, and distilled water (DW). A universal testing machine was used to measure the compressive strength after one and seven days of immersion. The un-immersed MTA was used as the control. To investigate the pH variation, MTA specimens were immersed in each solution and the pH was measured using a pH meter after 3, 6, 12, 24, 72, and 168 h. Changes on the MTA surface were also observed by SEM-EDS after seven days of immersion. Moreover, statistical analysis was performed by one-way ANOVA, Tukey's post-hoc test, and independent sample t-test. All experimental groups showed significantly higher compressive strengths compared to the control group (p<0.05). In addition, as the immersion time increased, the compressive strength gradually and significantly increased among all the groups. On the other hand, the difference was insignificant among solutions with the same immersion time (p>0.05). As the immersion time increased, the pH increased among all the groups, and the pH of samples immersed in saline and DW was significantly higher than that in SBF. The MTA surface immersed in each solution for seven days showed precipitates which mainly composed of Ca and Zr ions. Therefore, the type of contact solution does not significantly affect the compressive strength of MTA, but it significantly influences both the pH and surface condition

염색폐수의 유기물 부하율 및 담체 충진율에 따른 PEMT-MBBR의 COD 제거특성

박도현 ( Do-hyeon Park ),정병길 ( Byung-gil Jung ),윤태경 ( Tae-kyung Yoon ) 한국환경기술학회 2018 한국환경기술학회지 Vol.19 No.5

본 연구는 담체를 이용한 유동상 생물막 공정인 PEMT-MBBR 공정 내 담체 충진율과 염색폐수의 유기물 부하율에 따른 COD 제거특성을 평가하는데 그 목적이 있다. 글루코스를 이용하여 합성염색폐수를 조제하여 사용하였으며, 반응기 내 담체로는 폴리에틸렌 재질의 유동상 담체(PEMT)를 적용하였다. 실험 결과 PEMT-MBBR 내 유입 유기물 부하량이 증가할수록(HRT가 감소할수록) COD 제거속도는 증가하였지만, COD 제거효율은 급격히 감소하는 것으로 나타났다. PEMT-MBBR 내 담체 충진율이 70 % 일 때 MLSS 농도는 거의 7,000 mg/L 까지 증가하였다. 또한 수중 SBF의 양은 유기물부하량 8 kg/m³·day 까지는 증가하다가 그 이상이 되면 오히려 감소하는 것으로 나타났다. 본 실험에서 나타난 유동상 생물막법의 특성을 활용하면 대규모 공정에 적용할 수 있을 것이다. COD removal characteristics as functions of organic loading rate(OLR) of synthetic dyeing wastewater and carrier volume were studied using a lab-scale moving-bed biofilm reactor (MBBR). Polyethylene-based modular tube(PEMT) was used as a carrier material inside the reactor. The experimental results showed that COD removal rates were increased with increasing OLRs of synthetic dyeing wastewater in a PEMT-MBBR, but COD removal efficiencies were decreased sharply. When the carrier volume in the MBBR was reached to 70 %, the MLSS concentration was increased to almost 7,000 mg/L. Also, the suspended biofilm(SBF) concentration was increased until the OLR was reached to 8 kg/m³·day, but then decreased when OLR was 16 kg/m³·day. The results of this study could be scaled up and used as a design tool for the moving-bed biofilm systems of the dyeing wastewater treatment processes.

The Influence of Opposing Flow and Its Separation of SBF over Masan on Southeast Coast of the Korea

지효은,이화운,이귀옥,이순환,박순영,전원배 한국대기환경학회 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.4

A Sea breeze front (SBF) appears clear particularly if there is opposing wind, and the convergence zone along a SBF affects air quality in coastal areas. This study analyzes features of SBF separation in the presence of an opposing flow in the southeastern coastal area of Korea Peninsula. Using a Regional Atmospheric Modeling System (RAMS) numerical simulation and an opposing flow, two types of SBF were observed at Masan coastal area of Korea. In one,the SBF penetrated inland despite of the opposing flow at Jinhae (1100 LST), Wondong (1700 LST),Saenglim (1700 LST), and Miryang (1700 LST). In the other, the SBF remained on the coastline along with Jinhae (1100 LST), Masan (1400 LST), Jinbuk (1400 LST), and Gaecheon (1700 LST), because the inflow of the sea breeze was not sufficient to penetrate inland against the opposing flow. This study shows that SBFs are affected by the formation of an opposing flow, as well as the inflows of a sea breeze and the opposing flow.