• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.151-158
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• 2001

This paper describes an example of developing an integrated design system, Integrated Structural Design System for Reinforced Concrete Buildings(INDECON). INDECON incorporates a central database and three design modules: a preliminary design module(PDM), a structural analysis module(SAM), and a detailed design module(DDM). The development of INDECON begins with the development of design models including Design Object Model(DOM) which describes design data during the structural design process. The Design Object Model is transformed to Design Table Model(DTM) for the central database, and is specified to be in detail for the three design modules. Then the central database is implemented and managed by relational database management system(RDBMS), and the three design modules are implemented using C++ programming language. The central database in the server computer communicates with the design modules in the client computers using TCP/IP internet protocol. The developing procedure for INDECON in this paper can be applied for developing more comprehensive integrated structural design systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.688-694
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• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.482-485
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• 2016

안드로이드 애플리케이션의 UI 테스팅에서 무반응 문제의 탐색과 제거는 매우 중요하다. ANR(Application Not Responding)은 애플리케이션이 일정 시간 동안 응답이 없는 상태로, 내부적으로 어떤 스레드의 처리에 많은 시간이 소요될 경우 UI 스레드가 반응을 하지 않는 상황을 말한다. 안드로이드 플랫폼은 ANR 문제점 해결을 위해 DDMS와 Logcat과 같은 다양한 디버깅 도구들을 지원한다. 하지만 이러한 방법들은 ANR이 발생한 후에 대처하는 방법이므로 발생하기 전 ANR이 일어날 곳을 미리 탐색하고 회피하는 방법이 필요하다. 이 논문에서는 ANR이 발생하는 지점을 찾고 수정하여 프로세스가 원활한 응답성을 유지할 수 있도록 하였다. 그러기 위해 안드로이드 APK 파일을 추출하여 수행될 메시지를 포함하고 있는 인텐트 흐름 경로를 분석하여야 한다. 실행되는 응용 프로그램의 데이터 흐름과 응답시간 측정을 통하여 ANR이 발생 가능한 곳을 효율적으로 탐색할 수 있음을 보였다.

• 대한기계학회논문집A
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• 제29권1호
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• pp.22-29
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• 2005

A material cloud method, which is a new topology optimization method, is presented. In MCM, an optimal structure can be found out by manipulating sizes and positions of material clouds, which are lumps of material with specified properties. A numerical analysis for a specific distribution of material clouds is carried out using fixed background finite element mesh. Optimal material distribution can be element-wisely extracted from material clouds' distribution. In MCM, an expansion-reduction procedure of design domain for finding out better optimal solution can be naturally realized. Also the convergence of material distribution is faster and well-defined material distribution with fewer intermediate densities can be obtained. In addition, the control of minimum-member sizes in the material distribution can be realized to some extent. In this paper, basic concept of MCM is introduced, and formulation and optimization results of MCM are compared with those of the traditional density distribution method(DDM).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.593-598
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• 2000

In this paper the critical speed analysis and design sensitivity investigation are carried out with an APU(auxiliary power unit) gas turbine having a spline shaft connection. The DDM(direct differential method) is directly applied to formulate the critical speed design sensitivity problem of a general nonsymmetric-matrix rotor-bearing system. The design sensitivity analysis have shown that the critical speed change rate to the support modeling of the spline shaft connection point is extremely negligible, and thereby its design uncertainty is lifted. It has also been confirmed that the critical speeds up to the 4th are not sensitive to the design stiffness coefficients of 4-main bearings or supports, including two air foil bearings. Further, the critical speed change rate to the shaft-element length have shown quantitatively that the spline shaft has some limited influence on the 4th critical speed.

• 한국초지조사료학회지
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• 제18권2호
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• pp.151-156
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• 1998

This study was conducted to evaluate the forage yield and quality of Fesrulolium bmunii(Festuca prafensis Huds. x Lolium multiflomm Lam.) as a forage sources. The experiment was arranged in a randomized block design with four replications from Sep. 1995 to May 1998 at Chungnam University. Treatments consisted of two forage species, Festulolium bmunii(Pau1ita) and Dactylis glomerc;d4Potomac). The dry matter yields, nutritive value, N and energy balance were observed. The yields of DM, CPDM and DDM per area(ha) were higher for Potomac (P< 0.01) than for Paulita. The content of CP showed no difference between Potomac and Paulita, but NDF, ADF and lignin contents of Paulita were absolutly lower than those of Potomac (P<0.05). The retained N and energy were also high for Paulita compare to for Potomac. It could be suggested that Paulita has higher potential for improvement of the forage quality than Potomac and it have a potential to provide as a forage sources.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1329-1334
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• 1999

The curing characteristics of diglycidyl ether of bisphenol A (DGEBA) with diaminodiphenylmethane (DDM) as a curing agent were studied using differential scanning calorimetry (DSC), rheometrics mechanical spectrometry (RMS), and dielectric analysis (DEA). The isothermal curing kinetics measured by DSC were well represented with the generalized auto-catalytic reaction model. With the temperature sweep, the inverse relationship between complex viscosity measured by RMS and ionic conductivity obtained from DEA was established indicating that the mobility of free ions represented by the ionic conductivity in DEA measurement and the chain segment motion as revealed by the complex viscosity measured from RMS are equivalent. From isothermal curing measurements at several different temperatures, the ionic conductivity contribution was shown to be dominant in the dielectric loss factor at the early stage of cure. The contribution of the dipole relaxation in dielectric loss factor became larger as the curing further proceeded. The critical degrees of cure, at which the dipolar contribution in the dielectric loss factor starts to appear, increases as isothermal curing temperature is increased. The dielectric relaxation time at the same degree of cure was shorter for a sample cured at higher curing temperature.

• Steel and Composite Structures
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• 제6권3호
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• pp.183-202
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• 2006

The behavior of steel-concrete composite beams is strongly influenced by the type of shear connection between the steel beam and the concrete slab. For accurate analytical predictions, the structural model must account for the interlayer slip between these two components. This paper focuses on a procedure for response sensitivity analysis using state-of-the-art finite elements for composite beams with deformable shear connection. Monotonic and cyclic loading cases are considered. Realistic cyclic uniaxial constitutive laws are adopted for the steel and concrete materials as well as for the shear connection. The finite element response sensitivity analysis is performed according to the Direct Differentiation Method (DDM); its analytical derivation and computer implementation are validated through Forward Finite Difference (FFD) analysis. Sensitivity analysis results are used to gain insight into the effect and relative importance of the various material parameters in regards to the nonlinear monotonic and cyclic response of continuous composite beams, which are commonly used in bridge construction.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.19-26
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• 2017

The cure properties of ethoxysilyl bisphenol A type epoxy resin (Ethoxysilyl-DGEBA) systems with different hardeners were investigated, comparing with DGEBA and Diallyl-DGEBA epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The Ethoxysilyl-DGEBA epoxy resin system showed lower cure conversion rates than DGEBA and Diallyl-DGEBA epoxy resin systems. The conversion rates of these epoxy resin systems with DDM hardener are lower than those with HF-1M hardener. It can be considered that the optimum hardener for Ethoxysilyl-DGEBA epoxy resin system is Phenol Novolac type. These lower cure conversion rates in the Ethoxysilyl-DGEBA epoxy resin systems could be explained by the retardation of reaction molecule movements according to the formation of organic-inorganic hybrid network structure by epoxy and ethoxysilyl group in Ethoxysilyl- DGEBA epoxy resin system.

• 한국초지조사료학회지
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• 제23권2호
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• pp.121-128
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• 2003

본 시험은 초지를 상번초형 및 상+하번초형으로 혼파조합하여 조성하였을 때 목초의 건물수량, 품질 및 식생구성에 미치는 영향을 비교하고자 1999년 9철부터 2002년 12월까지 충남대학교 농업생명과학대학내 부속 초지시험포장에서 수행하였다. 공시된 혼파초지는 상번초형 혼파초지{orchardgrass, Potomac 40+tall fescue, Fawn 20+Festulolium braunii, Paulita 10+perennial ryegrass, Reveille 10+timothy, Climax 10+ red clover, Kenblue 5+ alfalfa, Vernal 5%)와 상ㆍ하번초형 혼파초지(orchardgrass, Potomac 40+tall fescue, Fawn 20+Kentucky bluegrass, New port(turf type) 10+redtop, Barricuda(turf type) 10+perennial ryegrass, Palmer III(turf type) 10+red fescue, Flyer II(turf type) 5+white clover, Regal 5%}의 두 처리를 두어 시험하였으며, 얻어진 시험결과는 다음과 같다. 1) 3년 평균 건물수량은 상ㆍ하번초형 혼파초지가 13,732kg/ha으로 상번초형 혼파초지의 13,117kg/ha 보다 약간 높았으나 유의적인 차이는 나타나지 않았다. 2) 상번초형 혼파초지와 상ㆍ하번초형 혼파초지간에 화학적 성분의 뚜렷한 차이는 없었다. 그러나 상번초형 혼파초지에서는 cellulose와 lignin 함량이 다소 높은 경향을 보였다. 한편, 건물소화율은 상ㆍ하번초형 혼파초지에서 다소 높은 결과를 보였다(p < 0.05). 3) 3년 평균 조단백질 건물수량은 두 처리간 차이가 인정되지 않았으나, 가소화건물수량은 상ㆍ하번초형 혼파초지가 10,670kg/ha으로 상번초형 혼파초지의 가소화건물수량 9,955kg/ha에 비하여 높은 결과를 가져왔다(p < 0.05). 4) 연차가 경과함에 따라 상번초형 혼파초지에서 식생을 높게 유지한 초종은 tall fescue, alfalfa 및 orchardgrass 등이었으며 timothy는 없어진 반면에, 상ㆍ하번초형 혼파초지에서는 white clover, tall fescue 및 orchardgrass 등의 식생비율이 높았으며, redtop, red fescue와 같은 하번초 초종의 식생도 비교적 고르게 유지되었다. 따라서, 상번초형 혼파초지에 비하여 상ㆍ하번초형 혼파초지는 목초의 건물수량과 품질에는 큰 영향을 미치지 못하였으나, 건물소화율 및 가소화건물수량이 높았고(p < 0.05), 연중 고르게 식생을 유지할 수 있었던 것으로 보아 생장습성이 다른 초종을 다양하게 혼파 이용하는 것도 좋을 것으로 사료된다.