• 비파괴검사학회지
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• 제9권1호
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• pp.39-47
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• 1989

As the necessity of the safety diagnosis of the concrete structure, more reliable ultrasonic technique to qualify the concrete is required. In this study, the artificial surface crack depth is measured using several types of the ultrasonic probes. As results, the horizontal shear wave probe is most useful to determine the crack depth compared to the other probes. For the surface wave probe, the ultrasonic wave path is changed with the surface crack depth.

• 수산해양기술연구
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• 제47권3호
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• pp.173-182
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• 2011

The purpose of this paper is to provide useful information for fishermen in the manner of investigation a sinking speed of current type tuna longline gear at the North Pacific Ocean as a new developed tuna longline fishing ground. The sinking depth of mainline in connection with different basket was investigated. The experiments were also performed with different materials such as Supermansen (i.e., PE) and Hitech (i.e., PA) for the mainline to investigate the sinking depth of mainline and hooks. Furthermore, the relation between the sinking depth of hooks and catches are investigated also. The sinking depth of mainline at the first and the last shooting basket shows deeper than that of middle part of a basket due to reduced shortening ratio. The sinking depth of mainline and hook with Hitech material shows more shallow than that of Supermanse material, even the Hitech case was designed to sink deeper than that of Supermanse case. The highest catches arise at the middle part basket as the hook number 7 with around 248m sinking depth. From the results, longline with Hitech material is needed to increase the sinking force for reaching the relevant sinking depth. Moreover, the current strength at the North Pacific Ocean will be considered for further commercial fishing.

• 대한수학회보
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• 제35권2호
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• pp.363-374
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• 1998

We investigate relationships of E-depths and T-codepths of modules in s short exact exact sequence. We give E-depths and T-codepths of some modules.

• 한국발생생물학회지:발생과생식
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• 제10권4호
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• pp.271-275
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• 2006

본 연구의 목적은 부화 후 67일 동안 대서양산 Haddock, Melanogrammus aeglefinus 치어의 초기성장을 조사하여, 본 종의 발생생물학과 양식 측면에서의 정보 제공하고자 한다. 전장성장은 $TL=3.5374e^{0.0536X}(r^2=0.8759$, TL은 전장이며, X는 부화 후 표본시일), 체중성장은 $BW=0.0002e^{0.1858X}(r^2=0.8671$, BW는 체중이며, X는 부화 후 표본시일)로 각 성장들은 지속적인 성장을 보였다. 체고와 가슴지느러미 길이는 연속적인 성장을 보여 체고성장은 $BD=0.3545e^{0.0778X}(r^2=0.9563$, BD는 체고이며, X는 부화 후 표본시일)였으며 가슴지느러미 길이성장은 $PL=0.0111e^{0.1591X}(r^2=0.9194$, PL은 가슴지느러미 길이이며, X는 부화 후 표본시일). 전장에 대한 체고의 상관관계식은 BD=0.2397X-0.5735($r^2=0.9957$, BD는 체고이며, X는 전장)이었으며 전장에 대한 가슴지느러미 길이의 상관관계식은 PL=0.1929X-1.3767($r^2=0.9882$, PL은 가슴지느러미 길이이며, X는 전장)이었다. 체고에 대한 가슴지느러미 길이성장은 PL=0.8117BD-0.9718($r^2=0.9814$, PL은 가슴지느러미 길이이며, BD는 체고)이었다. 체중에 대한 체고는 $BD=-9.4734X^2+19.046X+1.3672(r^2=0.9041$, BD는 체고이며, X는 체중)로, 체중에 대한 가슴지느러미 길이는 $PL=-6.379X^2+14.023X+0.3774(r^2=0.9494$, PL은 가슴지느러미 길이이며, X는 체중)이었다. 본 연구결과의 Haddock 치어 초기성장 특성은 Haddock 치어 사육에 도움이 될 것이다.

• 한국해안해양공학회지
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• 제19권5호
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• pp.457-466
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• 2007

북서태평양의 $115{\sim}150^{\circ}E,\;20{\sim}52^{\circ}N$ 사이의 해역을 $1/12^{\circ}$ 격자망으로 구성한 광역 조석 모델을 수립, 연안역 수심 조정이 전체 조석 모델 결과에 미치는 영향을 검토하였다. 최소 수심을 10 m에서 35 m까지 5 m 간격으로 증가시키며 계산된 모델의 정확도를 비교한 결과, $M_2,\;S_2,\;K_1$ 진폭의 정확도가 최소 수심이 25m일 경우최소 수심 10 m인 경우와 비교하여 각각 약 42%, 32%, 26% 정도 개선되는 것으로 나타났다. 제주도 주변 해역의 $M_2$ 조석 진폭은 연안역 수심 조정에 따라 약 20cm이상 차이를 나타냈으며 발해만 내에 존재하는 무조점의 위치도 크게 변화하였다. 해저마찰계수 및 최소수심에 따른 평균상대오차(ARE)를 계산해 본 결과 해저마찰계수 0.0015와 최소수심 25 m의 조합이 오차를 최소화 할 수 있는 최적 값으로 확인되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2730-2747
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• 2016

Due to the limitation of the bandwidth resource and capture resolution of depth cameras, low resolution depth maps should be up-sampled to high resolution so that they can correspond to their texture images. In this paper, a novel depth map up-sampling algorithm is proposed by exploiting the fractal internal self-referential feature. Fractal parameters which are extracted from a depth map, describe the internal self-referential feature of the depth map, do not introduce inherent scale and just retain the relational information of the depth map, i.e., fractal transforms provide a resolution-independent description for depth maps and could up-sample depth maps to an arbitrary high resolution. Then, an enhancement method is also proposed to further improve the performance of the up-sampled depth map. The experimental results demonstrate that better quality of synthesized views is achieved both on objective and subjective performance. Most important of all, arbitrary resolution depth maps can be obtained with the aid of the proposed scheme.

• 한국잡초학회지
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• 제2권1호
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• pp.47-52
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• 1982

담수심(湛水深)에 따른 논 잡초발생(雜草發生) 상태(狀態) 및 제초제(除草劑)의 약효(藥効)를 구명(究明)하기 위하여 수심(水深)을 3 수준(水準)(0, 3, 6 cm)으로하고 약제(藥劑)로는 Butachlor 300 33 % 유제(乳劑) Oxadiazon 12 % 유제(乳劑) Bifenox 7 % 입제(粒劑) 공시(供試)하여 시험(試驗)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 수심(水深)에 따른 잡초(雜草) 발생본수(發生本數)는 수심(水深)이 깊을수록 피(E. Crusgalli), 물달개비(M.Vaginalis)의 발생수(發生數)는 감소(減少)하나 가래 (P. distinctus)의 발생수(發生數)는 오히려 증가(增加)하였으며 올방개 (E.kuroguwai) 및 너도방동산이(C. serotinus)는 수심(水深)에 따른 차이(差異)가 적었다. 2. 수심별(水深別) 제초효과(除草効果)를 보면 Butachlor 300 및 Oxadiazon 유제(乳劑)는 3 cm 수심(水深)에서, Bifenox 입제(粒劑)는 6cm 수심(水深)에서 제초효과(除草効果)가 양호(良好)하였다. 3. 수심(水深)을 0cm로 낮게할 경우 제초효과(除草効果)는 Bifenox 입제(粒劑)보다는 Butachlor 및 Oxadiazon 유제(乳劑)가 좋았으며 3cm 수심(水深)에서는 제형간(劑型間) 차이(差異)가 없었다. 4 수심별(水深別) 약해(藥害)를 보면 Butachlor 300 유제(乳劑)는 수심(水深)이 얕을 수록 Oxadiazon 유제(乳劑) 및 Bifenox 입제(粒劑)는 수심(水深)이 깊을 수록 심(甚)한 경향(傾向)이나 수도생육(水稻生育)은 3 cm 수심(水深)에서 좋았다.

• 수산해양교육연구
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• 제26권1호
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• pp.34-48
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• 2014

Marine algal assemblages on the artificial reefs at three stations (Haengwon, Geumneung, Pyoseon in Jeju-do) and the growth pattern of Ecklonia cava with water depth were studied before and after rocky cleaning. Nine algal species occurred at three artificial reefs before rocky cleaning in July 2012, however, 19 algal species were found at three artificial reefs after rocky cleaning in July 2013. In particular, 13 of 19 species in 2013 were replaced by different species which were not found in July 2012. Algal biomass rapidly increased in July 2013 after rocky cleaning. The nMDS plot based on the presence and absence data of macro-algal assemblages on the artificial reefs showed that the species compositions between artificial reefs were similar to each other before rocky cleaning operations in July of 2012. However, after rocky cleaning, the species composition of macro-algal assemblages in Haengwon region was similar to that in Pyoseon region while that in Geumneung region was different to those in Haengwon and Pyseon regions in July 2013. It is needed to clarify the suitable water depth for transplantation of perennial Phaeophyta E. cava. According to the data on seasonal changes in total length, total weight, blade length, blade width, blade weight of E. cava, it began to grow rapidly from April and reached to the maximum value in June, and then degeneration of the blade occurred in July and continued to early August. Although the total length of E. cava at 10m water depth was larger than those at 5 m and 15 m water depths, there was no significant difference statistically among water depths by ANOVA test. However, in the values of total weight, blade length, blade width, and blade weight, the growth patterns at 5 m water depth were larger than those at 10 m and 15 m. Thus, it is assumed that the most suitable water depth for transplantation and its maximum growth and effective release of zoospores of E. cava will be 7~10 m water depth.

• 한국컴퓨터그래픽스학회논문지
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• 제23권1호
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• pp.39-48
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• 2017

본 논문에서는 3차원상의 두 강체 사이의 침투깊이 (penetration depth)를 명시적으로 민코우스키 합 (explicit Minkowski sum)을 생성하는 방법 ($PD_e$)과 암시적으로 민코우스키 합 (implicit Minkowski sum)을 생성 하는 방법 ($PD_i$)을 이용하여 계산하는 알고리즘을 제안하고 이들의 성능을 비교한다. 3차원 강체들 간의 침투깊이를 구하는데 성능상에 큰 장애가 되는 것이 민코우스키 합의 생성이다. 본 논문의 알고리즘들은 우선 물체의 중심 차 (centroid difference)와 운동 일관성 (motion coherence)기법을 이용하여 침투깊이를 예측한다. 특히 $PD_e$는 추측된 침투깊이에 부분 민코우스키 합을 명시적으로 생성 혹은 갱신하여 침투깊이를 빠르게 구한다. 반면에 $PD_i$는 민코우스키 합을 명시적으로 생성하기보다는 민코우스키 합에 접하는 접평면만을 반복적으로 생성하여 국소적으로 최적화된 침투깊이를 계산한다. 본 연구의 알고리즘들을 수천 개의 삼각형으로 이루어진 강체를 이용해 실험한 결과 수 밀리초 (millisecond) 이내의 빠른 속도로 침투깊이를 계산할 수 있다는 것을 실험적으로 보인다.

• Educational Technology International
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• 제20권2호
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• pp.195-221
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• 2019

This study explored middle and high school students' learning experiences using e-textbooks in online learning courses. Data were collected from in-depth interviews. The interviewees for this study were 19 students who enrolled voluntarily in an online mathematics and science inquiry program, actively participated in the online learning. The students generally have high academic achievement and motivation for learning in science and mathematics. Data were analyzed based on a grounded theory approach. As a result, the characteristics of the online learning environment using e-textbooks were conceptualized via three different categories including temporal, spatial, and technical. Such characteristics of the learning environment were able to provoke self-directed learning, extended learning, interactive learning, in-depth learning, improved ICT literacy, and formation of positive emotions and learning habits. Most of the learners showed positive feedback towards the use of e-textbooks, while some mentioned the technical limitations compared to conventional paper-based learning. This study suggested that e-textbooks are likely to induce positive experiences for learners in the context of online learning, so it is necessary to design contents that utilize various functions and advantages of electronic teaching materials in order to use e-textbooks effectively.