• 한국생산제조학회지
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• 제9권1호
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• pp.88-95
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• 2000

In this paper, an expansion-resonator type pulsation attenuator is proposed to absorb and attenuate flow an pressure ripple with high frequencies generated from hydraulic control systems. The basic principle of a pulsation attenuator proposed here is applied to propagation, reflection, absorption of pressure waves at the cross section of discontinuity and resonance in the pipeline. It has advantage of the compact size and high degree fo freedom for installation in hydraulic systems. The design scheme based on distributed parameter pipeline system with dissipative viscous compressible model is developed. To investigate the reduction of flow and pressure ripple with high frequencies produced by swash plate type axial piston pump, two kinds of attenuators are manufactured. It is experimently confirmed that the spectral intensity of flow and pressure ripple with high frequencies from the pump are reduced up to about 20$^{\circ}$~30dB by using attenuators proposed here. The calculated results were in good agreement with the measured values. From there sults of this study, it is shown that an expansion-resonator type pulsation attenuator is effective in a wide frequency ranges to attenuate the flow and pressure ripple from hydraulic components.

• 대한기계학회논문집B
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• 제26권3호
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• pp.384-393
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• 2002

The effects of hole expansion angle and the arrangement of nozzles on a film cooling system for a turbine-blade-shaped surface were experimentally investigated. Liquid crystal with flue-temperature correlation and an image processing system were employed to evaluate surface temperature. Distributions of cooling effectiveness were then presented to figure out the change of heat transfer characteristics with different geometric conditions of cooling-holes. It was found thats the averaged cooling efficiency on the suction surface was maximum with 10 degree of the cooling hole expansion angle. It was also shown that the averaged cooling efficiency on the pressure surface and the averaged cooling efficiency for dual array case were not affected by the hole expansion angle.

• 대한금속재료학회지
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• 제50권9호
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• pp.629-636
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• 2012

Volume shrinkage behavior accompanying the cure of resin formulations might be a critical factor when assembly processes using polymer materials are considered. In this study, cure shrinkage behavior with respect to resin formulation type and heating method was measured on sandwich structure samples by a thermomechanical analyzer (TMA). Quartz, used as a cover material for the sandwich structure, indicated the coefficient of thermal expansion close to $0ppm/^{\circ}C$. When a dynamic heating mode was conducted, a squeeze-out region and a cross-linking region for each resin formulation could be separated clearly with overlapping differential scanning calorimeter results on the TMA results. In addition, a cure shrinkage dominant region and a thermal expansion dominant region in the cross-linking region were distinguished. Consequently, the degree of cure at the initiation of the thermal expansion dominant region was successfully measured. Measurement of all resin formulations indicated the thermal expansion behavior exceeded cure shrinkage before full cure.

• 한국실내디자인학회논문집
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• 제38호
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• pp.65-74
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• 2003

The purpose of this study Is to find out the design guideline for women's hospital focusing on the patient needs. The results of research are as follows: 1) As a basic frame of evaluation model, the quality of service of medical facilities and patients' reaction to the physical environment are fixed as a variable called' satisfaction degree'. This study analyzes the influence on space efficiency evaluation according to the difference of types through basic model (Model I-1,2) as verification model to identify the difference between satisfaction degree of outpatients and that of inpatients. 2) The difference of satisfaction degree about the hospital facilities by space evaluation matrix is according to the types of inpatients and to space importance. 3) The control of importance degree about the interior facilities of the hospital according to the specific character of the hospital is necessary. Maintenance of the status quo, or reduction, or expansion is needed according to the satisfaction degree corresponding to the importance degree. Finally, the model is used to for the planning & design for the future women's hospital.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2179-2183
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• 2009

As urbanization is progressed, the network for distributing water in a basin become complex due to the spatial expansion and parameter uncertainties of water supply systems. When a long range water supply plan is determined, the total construction and operation cost has to be evaluated with the system components and parameter uncertainties as many as possible. In this paper, the robust optimization approach of Bertsimas and Sim is applied in a hypothetical system to find a solution which remains feasible under the possible parameter uncertainties having the correlation effect between the uncertain coefficients. The system components to supply, treatment, and transport water are included in the developed water supply system and construction and expansion of the system is allowed for a long-range period. In this approach, the tradeoff between system robustness and total cost of the system is evaluated in terms of the degree of conservatism which can be converted to the probability of constraint violation. As a result, the degree of conservatism increases, the total cost is increased due to the installation of large capacity of treatment and transportation systems. The applied robust optimization technique can be used to determine a long-range water supply plan with the consideration of system failure.

• 한국컴퓨터정보학회논문지
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• 제19권3호
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• pp.135-145
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• 2014

본 연구는 중학생의 학교적응성을 개선시키는 함의를 도출하고, 중학생의 사회적지지 정도에 따라 학교적응성에 미치는 정책적 방안을 제시 하는데 목적이 있다. 연구결과 중학생의 회복탄력성인 자기조절능력, 대인관계능력이 사회적 유능성과 학교적응성에 미치는 영향력의 관계에서 충동통제력, 자아존중감, 의사소통, 자아확장력은 사회적 유능성에 영향력이 미치는 것으로 나타났다. 감정조절력, 충동통제력, 자아존중감, 의사소통, 자아확장력은 학교적응성에 영향력이 미치는 것으로 나타났다. 중학생의 사회적 유능성이 학교적응성에 미치는 영향력이 높은 것을 알 수 있으며, 중학생의 자아확장력은 사회적 유능성에 가장 영향력의 정도가 높은 것을 알 수 있다. 중학생의 회복탄력성인 감정조절력과 타인공감성 및 자아확장력은 매개변수인 사회적 유능성에 유의미한 영향력의 차이가 있는 것으로 나타났다. 중학생의 회복탄력성인 충동통제력은 종속변수인 학교적응성에 사회적지지 정도에 따라 차이가 있는 것을 알 수 있고, 사회적 유능성은 종속변수인 학교적응성에 사회적지지 정도에 따라 차이가 있는 것을 알 수 있다.

• 산업경영시스템학회지
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• 제45권3호
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• pp.197-203
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• 2022

Urban space expansion is an important symbol of the urbanization process and has always been an important topic in urban studies. In addition, for sustainable city management, it is important to identify factors that can influence, such as the driving force and direction of urban space expansion, from the stage of establishing an urban development plan. To understand these factors, by observing the expansion process of a specific city, it is possible to sufficiently observe how the urban spatial dimension changes. Through a series of processes, the spatial growth characteristics of the city are analyzed, and the influence and results of important factors are analyzed. For this purpose, this paper examines the changes in the city's outer boundary and land use structure through monitoring data on urban areas of 14 cities in Hunan Province, China from 2000 to 2016. Temporal and spatial regularity according to the urban space expansion of these cities were analyzed, and a preliminary assessment was made on whether the urban space expansion is coordinated with the urban population growth. The assessment result showed: (1) The urban space of most cities has been extended rapidly in 2000-2015 however, the rate and the intensity of urban space expanding has been declining. (2) The construction of the industrial park is the core driving force of the urban space expanding, and the change of the urban space structure is manifested as enclave city expansion because that the industrial park is usually far away from the city center. (3) The population agglomeration is another driving force of the urban space expanding. At this time, the urban space expanding is like boundary extension. (4) Except Changsha city, all of the cities has a high urbanization-area-growth elastic coefficient. It means that most of the cities should enhance the land use degree.

• 실천공학교육논문지
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• 제14권1호
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• pp.179-194
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• 2022

2018년 일학습병행에 PBL(Project Based Learning) 방식이 P-Tech 유형에 처음 도입된 이후 2020년 시범사업으로 운영되고 있는 학위연계형 고숙련마이스터 과정에도 도입되면서 각 학과에서는 PBL 운영 규정에 맞게 표준이수체계를 개편하며, 그에 맞게 PBL 기반의 학습 및 훈련과정을 개발하여 운영하고 있다. 2021년 일학습병행 PBL의 확대 시행에 따라 그 운영 규정은 더욱 정교하게 개정되었다. 본 논문에서는 문헌연구를 통해 일학습병행 PBL의 특성, 학위연계형 고숙련마이스터 과정의 운영 절차 별 PBL 운영 규정과 가장 최근 시행된 PBL 운영 규정의 변경 내용을 상세히 고찰하였다. 이러한 사전 연구를 기반으로 한국기술교육대학교 IT융합SW공학과의 PBL 기반 표준이수체계 도출 과정 및 개발 결과, 운영 이후 표준이수체계의 적합성 검증을 위해 수행한 설문 조사 결과 사례를 소개하고, 변경되고 있는 일학습병행 PBL 운영 규정과 관련한 학위연계형 고숙련마이스터 과정의 도전 과제와 바람직한 개선 방향을 제시하였다. 본 연구는 대학에서 일학습병행 PBL을 원활하게 적용하기 위한 훈련과정개발의 참조를 제공할 수 있다. 또한 고숙련마이스터 과정을 포함하여 일학습병행의 PBL이 어떻게 발전해 나아가야 하는지에 대한 담론을 제시함으로써 일학습병행의 특성이 잘 반영된 고유의 PBL 제도 정착 및 안정적 확산에 기여할 것으로 사료된다.

• 한국식품조리과학회지
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• 제9권4호
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• pp.278-283
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• 대한수학회지
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• 제54권6호
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• pp.1801-1816
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• 2017

We study some spectral properties of Volterra-type integral operators $V_g$ and $I_g$ with holomorphic symbol g on the Fock-Sobolev spaces ${\mathcal{F}}^p_{{\psi}m}$. We showed that $V_g$ is bounded on ${\mathcal{F}}^p_{{\psi}m}$ if and only if g is a complex polynomial of degree not exceeding two, while compactness of $V_g$ is described by degree of g being not bigger than one. We also identified all those positive numbers p for which the operator $V_g$ belongs to the Schatten $S_p$ classes. Finally, we characterize the spectrum of $V_g$ in terms of a closed disk of radius twice the coefficient of the highest degree term in a polynomial expansion of g.