• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.711-714
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• 2008

The objective of this study is to analyze the relationship between the watershed characteristics and the critical duration of design rainfall. For estimation of critical duration, adjustment Huff's method and ILLUDAS urban runoff model were applied to urban 21 areas. Watershed characteristics such as area, channel length, channel slope, shape factor, and pipe density were used to simulate correlation analysis. The conclusions of this study are as follows; it is revealed that critical duration is influenced by the watershed characteristics such as pipe density, area and channel length. Also, multiple regression analysis using watershed characteristics is carried out and the determination coefficient of multiple regression equation shows 0.972.

• 공학교육연구
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• 제23권6호
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• pp.51-59
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• 2020

ABEEK's professional liberal arts education reflecting critical thinking, has been well received by professors and students in the engineering discipline. Also, the demand for further utilization of critical thinking within the engineering curriculum is increasing. To meet such demand, there is a need for experts in the area of critical thinking education and engineering education to come together and search for the most effective method in using critical thinking in engineering design education courses. In this paper, we were able to confirm, through specific application cases, that the problem-solving process of critical thinking can be effectively transferred to an engineering design process, and the elements and criteria of critical thinking can be used as a successful design tool. Also, we explore the possibility of further improving engineering education on the basis of critical thinking.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.1063-1072
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• 2003

Direct immersion cooling has been considered as one of the promising methods to cool high power density chips. A fluorocarbon liquid such as FC-72, which is chemically and electrically compatible with microelectronic components, is known to be a proper coolant for direct immersion cooling. However, boiling in this dielectric fluid is characterized by its small value of the critical heat flux. In this experimental study, we tried to enhance the critical heat flux by increasing the nucleate boiling area in the heat spreader (Conductive Immersion Cooling Module). Heat nux of 2 MW/㎡ was successfully removed at the heat source temperature below 78$^{\circ}C$ in FC-72. Some modified boiling curves at high heat flux were obtained from these modules. Also, the concept of conduction path length is very important in enhancing the critical heat flux by increasing the heat spreader surface area where nucleate boiling occurs.

• 한국정보전자통신기술학회논문지
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• 제2권1호
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• pp.37-42
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• 2009

디지털 신호 처리 분야에서 디지털 필터는 필수불가결한 요소이다. 디지털 필터는 이진수의 곱셈 및 덧셈을 기본으로 하는 것으로 많은 연산량을 필요로 한다. 디지털 필터 내의 곱셈기는 VLSI 기술을 이용한 디지털 필터의 설계에 있어 반도체 칩 내부의 넓은 영역을 차지하고 전력의 대부분을 소비하며, 필터의 critical path를 결정하여 필터의 성능을 결정하는 중요한 요소로서 작용 한다. 본 연구에서는 특히 디지털 필터의 복잡성(complexity)를 해소하고 critical path를 줄여 필터의 연산속도를 증가시키기 위한 방법으로 2의 보수로서 표현되는 이진수를 CSD(canonical signed digit)와 MSD(minimal signed digit)로 동시에 변환하여 표현하는 방법을 제안하였다. 제안된 방법은 VHDL로 구현하고 임의의 필터에 적용하여 필터의 critical path가 감소하는 것을 보였다.

• 한국정밀공학회지
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• 제26권4호
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• pp.120-127
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• 2009

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle. This paper concerns the improvement of spindle design using design of experiments. To improve the design of critical speed and weight of spindle, the experiments using central composite method have been carried out. The targets are critical speed and weight of spindle. For optimization of critical speed and weight and optimization of only critical speed by operation of all area search through response optimizer, the result of analysis has improved design of each factor. Finite element analyses are performed by using the commercial codes ARMD, CATIA V5 and ANSYS workbench. From the results, it has been shown that the proposed method is effective for modification of spindle design to improve critical speed and weight.

• 중환자간호학회지
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• 제10권1호
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• pp.41-50
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• 2017

Purpose: The purpose of this study was to describe what critical care nurses perceived about life-sustaining treatment at end of life. Methods: A qualitative content analysis method was utilized. The unit of analysis was interview text obtained from fifty critical care nurses of a general hospital. Results: Seven categories in two content areas were abstracted. In the negative perception area, the following five categories were abstracted: patients' suffering, dying with damaged dignity, patients' isolation from family members, regret about choosing life-sustaining treatment, and family members' burden. In the positive perception area, the following two categories were abstracted: willingness to sustain life and duty as family members. Conclusions: Nurses have better competencies pertaining to understanding patients' responses and suffering than any other health care professions do. Nurses should play an important role in advocating for patients and their family in the process of end-of-life care decision making.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1454-1459
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• 2004

The major parameters governing the fluid dynamical and thermo-dynamical behavior in the large pipeline network system are friction loss and the pipeline length. But in local pipeline networks and relatively short distance pipeline system, secondary loss and the considerations of the moving states of the fluid machine are also important. One of the major element in local pressure control system is pressure regulator. It causes the variations of the physical properties in that pipeline system. When it is under working, the accurate analysis of the flow properties is so difficult. In this study, some numerical approaches to investigate the critical-flow-characteristics of the pressure regulator have been done according to the variations of the opening ratio or cross-sectional area and the detail examinations and considerations of the pressure regulator as a pipeline network elements have been carried. Finally the flow-flied distributions and critical-flow-characteristics have been presented in detail and the critical flow phenomena and the relation to the opening ratio or cross-sectional-area ratio have been studied.

• 대한조선학회논문집
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• 제55권3호
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• pp.274-280
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• 2018

This paper deals with the calculation of vulnerable areas of critical components required for the assessment of naval ship's vulnerability. Taking into account the effectiveness of threatening weapons, the probability density function of damage was used to assess vulnerable areas or vulnerabilities of critical components. It is shown that the vulnerable area of critical component can be simply computed from the damage function. Considering the weapon effectiveness of fragmentation and explosion on the target, both Carleton Damage Function and Rectangular Cookie Cutter Function representing the probability of damage are applied to the vulnerable area assessment. Carleton damage function is utilized to describe the weapon-target interaction in the vulnerability analyses. A problem of blast effect against an assumed naval ship is chosen as a case study. Vulnerability is evaluated by applying the suggested method to the equipments arranged in the engine room of the virtual ship.

• 인문언어
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• 제7집
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• pp.335-353
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• 2005

In recent years there has been much discussion about whether there is a critical, or sensitive period for language acquisition. Research on a critical period provides an excellent example around which we can organize a discussion of the behavioral and neural evidence. In this paper, the early history of critical periods and evidence for the existence of critical periods in various domains of human cognition and learning are reviewed. Followed by this overview, evidence for a critical period in both linguistic and non linguistic area are presented. The paper then provides some unresolved questions regarding a critical period in language acquisition and states what the outcome of this issues mean for an understanding of language acquisition. Finally the paper concludes with some educational implications of a critical period for practice.

• 중환자간호학회지
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• 제5권2호
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• pp.37-48
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• 2012

Purpose: The purpose of the study was to evaluate how advanced practice nurses (APNs) recognized their work by analyzing nursing outcomes. The ultimate goal was to examine the utility of APNs by connecting their work to the outcomes. Methods: Cross-sectional survey was conducted to collect the data from 59 APNs in a tertiary hospital lovated in Seoul, Korea. The questionnaire with 84 outcome indicators for advanced practice nurses was used. Descriptive statistics were used to analyze the data. Results: Among 84 outcome indicators, 11 indicators were associated with the work of APNs. Majority of these findings were included in the categories of clinical results and satisfaction. Items identified to be associated with the work of APNs were different among oncology nursing area, surgical speciality area, emergency care area, and critical care area. Conclusion: The results of the study indicated that the works of APNs were relevant to education/counseling/training and interpersonal relationship with other health professionals. The results of the study could be helpful to delineate the work characteristics of APNs and increase the utility of APNs in Korea where roles of APNs are not yet clearly delineated in most clinical settings.