• 산업기술연구
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• 제18권
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• pp.323-328
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• 1998

A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

• 대한전기학회논문지
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• 제41권8호
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• pp.938-946
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• 1992

A novel 2-dimensional matched filter of the parallel-jaw type using fuzzy logic is proposed for bin picking. Specifically, the averaged pixel intensity of the windowed region for the filtering is considered to be fuzzy. Also membership functions for darkness and brightness are designed by employing the intensity histogram of the image. Then a rule is given to know how much a windowed region can be a possible holdsite. Furthermore eight rules are made to determine the part orientation, where Mamdani's reasoning method is applied. The proposed technique shows better performances than that of the conventional matched filtering technique in the following senses` 1) most of holdsites determined by the proposed technique are not concentrated at the locations nearly the end of part and 2) our filter is rather insensitive to noises than the conventional method. To show the validities of our proposed technique, some experimental results are illustrated and compared with the results by conventional matched filter technique.

• 한국임상수의학회지
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• 제25권6호
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• pp.549-552
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• 2008

An eight-month-old, intact female Jindo, weighing 9 kg with a one-day history of acute bloody diarrhea was referred. Plain abdominal radiographic findings included evidence of a soft tissue tubular mass within the dilated colon. In ultrasonographs, a target-like mass was identified with multiple hyperechoic and hypoechoic parallel wall layers. A barium enema showed a large radiolucent filling defect within the colon and a completely occlusive lumen. On the basis of these images, ileocecocolic and colocolic intussusception was diagnosed. Surgical manual reduction, resection and anastomosis were performed. The patient recovered normally without any complications or recurrence.

• ALGAE
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• 제28권2호
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• pp.149-160
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• 2013

Six species of the genus Symphyocladia are currently recognized worldwide, all of which are reported to grow on the Korean coast. We described a new species Symphyocladia glabra sp. nov. based on morphological and molecular evidence. The new species is characterized by mostly an erect and broad thallus, the parallel arrangement of numerous apical cells, completely fused congenital cells, a corticated basal portion of faint midrib with six to eight pericentral cells, rhizoids cutting off from pericentral cells, and absent vegetative trichoblasts. The new species has morphological similarity to S. marchantioides and S. jejuinsula. However, S. glabra sp. nov. is distinguished from S. marchantioides by the corticated lower portion of the thallus and the absence of vegetative trichoblasts, and S. jejuinsula by number of pericentral cells and the fact that the thallus does not taper upward. The phylogeny of rbcL sequences indicated that S. glabra sp. nov. is definitely a separate entity within the genus Symphyocladia.

• Structural Engineering and Mechanics
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• 제88권3호
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• pp.201-208
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• 2023

In this work, the effect of the correction fibers direction on the efficiency of repairing damaged composite plates was highlighted. The composite plates studied in this work consist of eight layers of graphite/epoxy, while the patch used in this repair consists of four layers of the same type. The results obtained in this work, whether with regard to the experimental or analytical side, showed that the fibers orientation affects the repair efficiency, so the closer the angle of fibers inclination is to the tensile strength direction, the performance of the composite material is ideal. Hence, we conclude that the composite materials with longitudinal fibers (Parallel to tensile strength) is the most powerful and efficient material in performance.

• 대한치과교정학회지
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• 제50권6호
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• pp.401-406
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• 2020

Objective: To investigate and compare the slot sizes and parallelism of metal injection molding (MIM) and computerized numerical control (CNC) brackets. Methods: The following four MIM bracket series with 0.022-inch (in) slots were selected for investigation: Di MIM mini Twin (Ortho Organizers), Mini Diamond Roth (Ormco), Gemini MBT (3M Unitek), and Formula R Roth (Tomy). The following four CNC bracket series with 0.022-in slots were selected for investigation: Econoline MBT (Adenta), Legend mini MBT (GC Orthodontics), Crown mini MBT (Adenta), and Evolve MBT (DB Orthodontics). The slot dimensions were measured using an optical microscope (XTCam-D310M; Mitutoyo) with a resolution of 1 ㎛. The results were statistically analyzed using one-way analysis of variance and the Tukey post-hoc test with a significance level of 0.05. Results: The results indicated that all the investigated slot sizes were oversized with respect to the manufacturers' specifications (0.022 in). Among the eight bracket series, the Di MIM bracket (MIM) was the most oversized by 10.4%, whereas the Evolve bracket (CNC) was the least oversized by 2.6%. The slots in seven of the bracket series had divergent walls instead of parallel ones. The Evolve bracket alone had parallel slot walls. Conclusions: Regardless of the manufacturing method, all the slot sizes of the brackets investigated in this study were significantly oversized; most of the slot walls were nonparallel, except for those of the Evolve bracket. This study could not establish that the CNC method was more accurate than the MIM method in manufacturing bracket slots.

• Journal of the Korean Wood Science and Technology
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• 제18권2호
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• pp.67-78
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• 1990

This study was performed to determine the characteristics of physical and mechanical properties of domestic wood based materials; plywood, particleboard, medium density fiberboard. Main items of tested properties were panel size, moisture content, water absorption, linear expansion and thickness swelling, glue bond shear strength, bending properties(stress at proportional limit, modulus of rupture. modulus of elasticity), tensile strength, screw holding strength, and internal bond as neccessary. the results were discussed mainly with Korean Standards. The obtained conclusions are as follows; 1. Length and width of 3mm thin plywood(3-ply) and 12mm thick plywood(7-ply) were satished with KS-standard, but thicknesses of these panels were not- passed tolerance limit except one of eight makers. 2. Length and width of particleboard and medium density fiberboard were greater than the tolerance limit value of KS standard, but the thicknesses of these panels were passed this value. 3. Moisture contents of 12mm thick and 3mm thin plywood were satisfied with KS-standard except one mill made 3mm thin plywood. 4. Moisture absortion of plywood was not passed tolerance limit of KS-standard but particleboard was satisfied with this standard value. 5. Dry and wet shear strengths in glue bond of 3mm thin plywood were not reached to KS-standard, but those of 12mm thick plywood were sufficiently satisfied with KS standrad. 6. Modulus of ruptures, parallel to grain and perpendicular to grain of plywood, and particleboard and medium density fiberboard were satisfied with KS-standard. 7. Tensile strengths, parallel to grain and perpendicular to grain of plywood were satisfied with allowance stress of US product standard PS 1-74. 8. Screw holding strength of particleboard was not reached to KS standard, but internal bond was satisfied with KS standard.

• 대한전자공학회논문지SD
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• 제44권2호
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• pp.121-126
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• 2007

본 논문은 redundant 다치논리 (redundant multi-valued logic, RMVL)을 이용하여 디멀티플렉서 (demultiplexer)를 설계하였다. 설계한 회로는 RMVL을 이용하여 직렬 이진 데이터를 입력받아 병렬 다치 데이터로 변환하고 다시 병렬 이진 데이터로 변환한다. RMVL은 redundant 다치 데이터 (multi-valued data) 변환으로써 기존 방식 보다 더 높은 동작속도를 얻을 수 있도록 한다. 구현한 디멀티플렉서는 8개의 적분기로 구성되어 있다. 각 적분기는 누적기, 비교기, 디코더, D 플립플롭으로 구성된다. 0.35um 표준 CMOS 공정으로 구현하였으며 포스트 레이아웃 시뮬레이션 (post-layout simulation)을 통해 검증하였다. 본 논문의 디멀티플렉서의 최대 데이터 전송률은 9.09 Gb/s이고 평균 전력소모는 69.93 ㎽이다. 높은 동작 주파수를 가지는 초미세 공정에서 이 디멀티플렉서를 구현한다면 9.09 Gb/s보다 더 높은 속도에서 동작할 수 있을 것이다.

• 가정과삶의질연구
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• 제20권4호
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• pp.149-164
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• 2002

The purpose of this study was to identify the types of social networks of urban housewives according to different network composition patterns and to analyze the structural and functional characteristics of identified types. The data used in this study were collected from 589 full-time housewives residing in Taejeon city. The major findings are as follows: 1) The social networks of housewives in urban nuclear families were classified into eight types: the kin network, the non-kin network, the kin-centered network, the friend-centered network, the neighbor-centered network, the associate-centered network, the parallel network, and the decentralized network. 2) The structual characteristics (size, density, homogeneity, duration, proximity, frequency, closeness, direction) varied according to the type. The kin network type and the non-kin network type showed extreme degrees in network characteristics. The parallel network type and the decentralized network type showed an average level of network characteristics. The kin-, friend-, neighbor-, and the associate-centered types showed network characteristics of an intermediate level between the single-category types and the decentralized type. 3) The average levels of function of social network types were different in only two(service support, interference) of the six function areas(emotional support, service support, material support, information support, social companionship support, interference). The average level of service support by the non-kin network type was higher than other types. The average level of interference by the kin-centered network type was higher than other types, and that of the neighbor-centered network type was lower than other types. On the other hand, the total amount of function performance of social network types was different in all function areas. The total amount of social support given by the decentralized network type was greater than the other types. The total amount of interference given by the non-kin network type was smaller than the other types.

• 한국정보과학회논문지:시스템및이론
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• 제36권5호
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• pp.335-343
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• 2009

교차큐브는 병렬처리 시스템의 상호연결망으로서 널리 알려진 하이퍼큐브와 많은 면에서 비슷하면서도 절반 정도의 지름을 가지는 등 개선된 망 성질들을 가지므로 각광 받아 왔다. 크기 $4{\times}2^m$인 메쉬의 복사본 두 개, 혹은 크기 $8{\times}2^m$인 메쉬의 복사본 네 개가 교차큐브에 연장율 1, 확장율 1로 임베딩 될 수 있음이 알려져 있다.[Dong, Yang, Zhao, and Tang, 2008]. 그러나 양변의 길이가 모두 8 보다 큰 메쉬 다수 개가 교차큐브에 연장율 1, 확장율 1로 임베딩될 수 있는지는 알려진 바가 없다. 이 논문에서는 크기 $2^n{\times}2^m$인 메쉬의 복사본 $2^{n-1}$개가 교차큐브에 연장율 1, 확장율 1로 임베딩될 수 있음을 보인다. $n{\geq}1$, $m{\geq}3$. 이 연구 결과는 연장율과 확장율이라는 주요 임베딩 측정 척도에서 최적이다. 또한 이 연구 결과는 메쉬 구조를 가지는 다수 개의 작업을 교차큐브 구조를 가지는 병렬 컴퓨터에 할당하는데 효과적으로 활용될 수 있다.