• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1180-1185
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• 1999

Modispersed silica fine particles were produced from the hydrolysis of $Si(OC_2H_5)_4$ by using batch-semibatch mixed systems. Four types of mixed process, i.e., batch-batch, batch-semibatch, semibatch-batch, semibatch-semibatch, were used in order to measure mean particle size, particle size distribution, yield, and packing density. As a result of the test, silica particles prepared by semibatch-semibatch process were larger than those prodeced from any other systems in particle size and yield. On the other hand, silica particles prepared by batch-semibatch process were better than those produced from any other systems in particle size distribution and packing density. Especially, it was found that particle size of $SiO_2$ prepared by semibatch-batch process decreased with increasing the reaction time. Therefore, batch-semibatch process was a successful method for controlling the size, i.e., a narrow distribution of a particle size which ranges to several microns.

• Journal of the Korean Arthroscopy Society
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• v.8 no.1
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• pp.37-44
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• 2004

Purpose: To evaluate the optimal number of additional half hitches for achieving an optimal knot-holding capacity (KHC) of Lockable sliding knots. Methods: Four configurations of arthroscopic knots (Duncan loop, Field knot, Giant knot, and SMC knot) were tested for their knot-holding capacity. For each knot configuration, 6 sequential knots were made including the initial sliding knot and additional 5 knots by incrementing one half hitches at a time. Each added half-hitch were in reversing half-hitches with alternate posts (RHAPs) fashion. For each sequential knot configuration, 12 knots were made by No. 2 braided sutures. On the servo-hydraulic material testing system (Instron 8511, MTS, Minneapolis, MN), cyclic loading, load to clinical failure (3-mm displacement), load to ultimate failure, and mode of failure were measured. Results: Most of the initial loop without additional half-hitch showed dynamic failure with cyclic loading. The mean displacement after the end of cyclic loading decreased with each additional half-hitches. SMC and Giant knot reached plateau to 0.1 mm or less displacement after one additional half-hitch, shereas Field and Duncan loop needed 3 additional half-hitches. The SMC and Duncan knots needed 1 additional half-hitch to reach greater than 80N at clinical failure, whefeas the other 2 knots needed2 additional half-hitches. For the load exceeding 100N for clinical failure, the SMC knot required 3 additional half-hitches and the other three knots needed 4 additional half-hitches. As the number of additional half-hitches incremented, the mode of failure switched from pure loop failure (slippage) to material failure (breakage). Duncan loop showed poor loop security in that even with 5 additional half-hitches, some failed by slippage (17%). On the other hand, after 3 additional half-hitches, the 3 other knots showed greater than 75% of failure by material breakage mode (SMC and Field 92%, Giant 75%). Conclusion: Even with its own locking mechanism, lockable sliding knot alone does not withstand the initial dynamic cyclic load. For all tested variables, SMC knot requires a minimum of 2 additional half-hitches. Duncan knot may need more than 3 additional half-hitches for optimal security. All knots showed a mear plateau in knot security with 3 or more additional half-hitches.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.66-68
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• 2000

웹에서 공개하는 정보의 많은 부분이 문자에 의존해서 제공되고 있으며, 이렇게 단어의 여러 형태로 구성된 웹 문서에서 원하는 정보를 찾아 추출하기 위한 노력은 다양하게 시도되고 있다. 본 논문에서는 전자부품관련 정보 제공 사이트와 관련해서 텍스트 기반과 웹 문서가 갖는 특별한 형태의 태그를 포함하는 형태에서 테이블 형식의 정보 표현과 같이 반 구조적(semi-structured) 문서에서의 정보 추출 방법과 이를 적용한 시스템을 구성하여 정보 추출의 가능성을 제시하고자 한다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.131-134
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• 2000

음성신호처리에서 스펙트럼 분석은 매우 중요하다. 하지만 스펙트럼 분석을 위해서 사용되는 윈도우에 의해 생기는 누설에러지 때문에 음성신호의 스펙트럼 정보가 왜곡된다. 본 논문에서는 스펙트럼 분석 시 발생되는 창함수 사용에 의해 생기는 누설에너지를 최소화하기 위한 새로운 창함수를 제안하고자 한다. 그 형태는 전체 창함수크기의 반을 방형창으로 나머지 반을 해밍창으로 하고 창의 처음 부분은 $\pm$20표본에서 영점을 찾아주는 것이다. 이 창함수의 특징은 신호분석에 있어서 왜곡은 크지만 그 형태에 있어서 가장 이상적인 방형창함수의 장점과 side lobe가 작아 비교적 왜곡이 적은 해밍창함수의 장점을 취한 것이라 하겠다. 실제 음성 신호에의 적용에 있어서 방형창과 해밍창의 적용비는 신호의 종류 및 용도에 따라 달리할 수 있다. 제안한 창함수는 해밍창함수 보다는 좁은 main lobe 특성으로 음성신호의 단구간 스펙트럼 분석시 음성의 빠른 변화특성을 적절히 보여줄 수 있고 방형창보다는 side lobe의 영향을 줄일 수 있다.

• Journal of Aquaculture
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• v.18 no.3
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• pp.142-146
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• 2005

In this study, the reattachment processes of small and medium size of spot of Mytilus coruscus and M. edulis were observed. The small spats (Shell length, SH, $3{\sim}7mm$) of hard shelled mussel, M. coruscus showed 100% reattachment rate within 7 minutes after the detachment of byssus thread and 100% survival rate. While large spats (SH 25 mm) showed 85% reattachment rate within 5 hours and 100% survival rate for 24 hours. The reattachment rate of M. edulis (SH 30 mm) was higher than that of M. coruscus (SH, 28 mm). The thread consisted of three identifiable structures; adhesive disc, adhesive thread and adhesive root. The adhesive disk and adhesive thread of M. coruscus were larger and thicker than those of M. edulis, whereas the thickness of adhesive root was the other way round. Further studies are required to identify the relationship between the structure of byssus thread and attachment ability. This study suggests that the sizes of spats could be an important factor in determining the timing of removing and reattaching mussel seedling for aquaculture or releasing to the sea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.3
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• pp.156-164
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• 1999

Two analytical solutions for wave diffraction by a semi-infinite breakwater, which Penney and Price (1952), and Stoker (1957) presented, are rederived. Since in previous works the derivations were skipped or briefly given, in the paper the derivation is brought into focus. Numerical computations of the solutions are presented and solution behavior of Stoker's method due to a number of terms in the series is analyzed.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.162-165
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• 2002

We propose an optical configuration for a transflective display mode using a transflective film and a half-wave AFLC cell whose in-plane tilt angle is 22.5。. It provides high brightness and high contrast in the reflective mode as well as in the transmissive mode.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.243-247
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• 2014

In this paper, we design two types of the sensor module to measure the partial discharge causing failures and electric fires for power incoming/distributer. And evaluate the performance thereof. Analyze the correlation of the phase current and the partial discharge and overheating. Proposes to apply the stability index by utilizing the analyzed information and use in order to prevent the failure or electrical fire of the power incoming/distributer.

• Journal of the Korean Home Economics Association
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• v.17 no.3
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• pp.71-83
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• 1979

한국 유아 교육기관에서 3,4,5세 어린이 63 명을 대상으로 시간에 따라 표집을 하여 관찰한 결과 변량분석하였다. 그 결과 , 이 세 연령의 어린이에게서 병행놀이가 다른 어느 형태의 놀이보다도 가장 많이 나타났으며, 나이가 많아짐에 따라 증가하는 것으로 나타났다.두번째로 많이 나타난 안하는 상태의 행동은 연령의 증가에 따라서 줄어드는 경향을 보였고, 3세에서 여섯 번째로 나타났던 협동놀이가 5세에서는 세 번째로 많이 나타나 증가의경향을 보였다. 손으로 다루는 장난감과 바퀴달린 장난감의 사용은 연령증가에 따라 감소하는 경향을 나타냈으나 미술 공예 자료와 책의 사용은 증가하였다. 장난감 사용에 있어 남녀의 차이를 나타냈는데, 즉 남아들은 여아들 보다 손으로 다루는 장난감, 나무토막, 바퀴달린 장난감들을 많이 사용하고 여아들은 소꼽놀이와 미술 공예 자료를 더 많이 갖고 노는 것으로 나타났다. 또 오전 오후반으로 나뉘어진 4세에서는 오후반 남아들이 오전반 남아들에 비해 소꼽놀이 미술공예자료를 더 많이 사용하였고, 여아들은 오후반이 오전반보다 미술 공예 자료를 더 많이 사용하였다. 또 오전반은 4세 여아들은 같은 성 같은 연령이 어린이와 가장 오랫동안 노는 경향을 나타냈다. 본 연구결과와 Patern의 연구결과에 대한 설명을 Parten의 놀이이론과는 다른 입장에서 설명하였다.

• Animal Systematics, Evolution and Diversity
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• v.16 no.2
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• pp.191-202
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• 2000

A taxonomic study of the Oxyporinae including a single genus Oxyporus Fabricius in Korea is presented. Members of the genus are known to be obligate inhabitants on fleshy mushrooms. They are characterized by crescent-shaped last labial palpomere. Nine species are recognized, five of which are reported for the first time in Korea (Oxyporus basicornis Cameron, O. basiventris Jarrige, O. crocatus Fauvel, O. niger Sharp, O. triangulum Sharp). The illustrations, descriptions, and key to the Korean species of the Oxyporinae are presented.