• Journal of Aerospace System Engineering
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• 제8권3호
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• pp.41-46
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• 2014

Fatigue evaluations for the rotor blades of commercial or military rotorcraft have been carried out using the safe life concept since 1950s. Particularly, in the case of a rotor blade made of a composite material, a highly reliable fatigue life could be predicted by evaluation the cumulative damage using combination of fatigue life curve and load spectrum. However, there is a limit in adequately evaluating the strength reducing phenomena caused by damages or defects generated during the manufacturing process or impact damage induced by operational usages, using only the safe life concept. In this study, the fatigue evaluation process based on the damage tolerance concept is described and illustrated by means of successful application to substantiate the retirement time of composite rotor blades.

• Journal of the Korean Institute of Landscape Architecture
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• 제17권1호
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• pp.55-68
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• 1989

^x This paper focuses on clarifying the diverse conceptions of landscape, of which ambiguity gives rise to confusion to the theory and practice of landscape architecture. Landscape in the form of landscipe has once indicated land, a defined space or a humanized environment, cultivated and inhabited for the purpose of biological sustenance of ordinary people. With the advent of landschap(landscape) painting, its concept moved from the real world to the scenery, a prospect, 'a portion of earth's surface that can be seen at once by a man who is himself upon the surface. 'Once appeared, it remained as a central concept until the 19th century when the modern land-scape architecture, which claims to stand for the democratic planning and environmental design, emerged. However, it still survives as the most popular concept :a landscape is a man-made, beautiful scene. To the contrary, the geographers hold that a landscape is not an actual scene viewed by a particular observer, but is a generalization induced from the observation of many individual scene. Since it is not only very attractive to the general public, but also very important to the designers, scholars and artists, operational definitions of landscape are urgently needed.

• Journal of Korean Port Research
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• 제5권1호
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• pp.3-22
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• 1991

In recent years the hatchcoverless(or open-top) containerships have been evolving as a promising new concept for enhanced containership operations. The design concept of the hatchcoverless containership is innovative and appears to be worthwhile. especially from an operational viewpoint. The hatchcover and container lashing system have been eliminated and the containers are stacked in open hold fitted with cell guides. Thus this design concept can provide a more efficient and economically viable fleet due to the reduced time and cost of loading and unloading operations. Therefore turnaround time in port is also greatly reduced. This examination provides. brief background, advantages, brief review of new building containership, highlights of the pertinent areas requiring special consideration and recommendations of possible analyses herein.

• Journal of Korean Academy of Nursing
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• 제19권1호
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• pp.92-98
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• 1989

Concept analysis is a formal linguistic exercise to determine certain defining attributes. The basic purpose of concept analysis is to clarify ambiguous concepts in a theory, and to propose a precise operational definition which reflects its theoretical base (Walker, 1983, 27~28). In later life, elderly people are faced with various psychological problems such as depression, and lowered self-esteem for these psychological problems of the elderly. Reminiscence has been studied as an effective therapeutic measure by gerontologists and psychologists. It is considered to have potential as an effective nursing intervention with geriatric clients. The purpose of this paper was to explore the feasibility of adopting reminiscence as a nursing intervention through analysis of the concept. The concept can be defined as follows : Reminiscence is thinking and talking about one's past with or without a specific purpose. It is a composite mental process which involves psychological, emotional, and social interactional aspects. The defining attributes of reminiscence are : 1. Thinking about past experiences which are meaningful to oneself. 2. It includes the emotional aspect of past experiences. 3. It occurs with or without specific purposes. 4. It is communicated to others by means of language and the subject has the feeling of being heard. In regard to the consequences of reminiscence, it is expected to contribute to psychological adaptation by providing a sense of self-fulfillment and self-achievement, promoting the discovery of the meaning of life, decreasing depression, and overcoming guilt feelings and conflict about one's past. However, if the past is regarded as a total failure, it may be harmful to the psychological well-being of the subject.

• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.67-72
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• 2014

The next generation small satellite-1 (NEXTSat-1) program has been kicked off in 2012, and it will be launched in 2016 for the science missions and the verification of space core technologies. The payloads for these science missions are the Instrument for the Study of Space Storms (ISSS) and NIR Imaging Spectrometer for Star formation history (NISS). The ISSS and the NISS have been developed by Korea Advanced Institute of Science and Technology (KAIST) and Korea Astronomy and Space science Institute (KASI) respectively. The ISSS detects plasma densities and particle fluxes of 10 MeV energy range near the Earth and the NISS uses spectrometer. In order to verify the spacecraft core technologies in the space, the total of 7 space core technologies (SCT) will be applied to the NEXTSat-1 for space verification and those are under development. Thus, the operation modes for the ISSS and the NISS for space science missions and 7 SCTs for technology missions are analyzed for the required operation time during the NEXTSat-1's mission life time of 2 years. In this paper, the operational concept of the NEXTSat-1's science missions as well as the verification of space core technologies are presented considering constraints of volume, mass, and power after launch.

• Education of Primary School Mathematics
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• 제23권1호
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• pp.45-61
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• 2020

The concept of equality is given as a way of reading the equal sign without dealing it explicitly in elementary school mathematics. The meaning of the equal sign can be largely categorized as operational and relational views. However, most elementary school students understand the equal sign as an operational symbol for just writing the required answers. It is essential for them to understand a relational concept of the equal sign because algebraic thinking in middle school mathematics is based on students' understanding of a relational view of the equal sign. Recently, the relational meaning of the equal sign is emphasized in arithmetic. Hence it is necessary for elementary school students to have some activities so that they experience a relational meaning of the equal sign. In this study, we investigate the meaning of the equal sign and contexts of the equal sign in elementary school mathematics to discuss explicit ways to emphasize the concept of equality and relational views of the equal sign.

• Journal of the Society of Naval Architects of Korea
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• 제46권2호
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• pp.97-104
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• 2009

Ever increasing fuel prices, almost doubled in the last three years, and global pressure to reduce their environmental impact have been enforcing commercial vessel operators and designers to re-assess current vessel designs with emphasis on their propulsion systems and operational practices. In this paper the "Inclined Keel Hull (IKH)" concept, which facilitates to use larger propeller diameter in combination with lower shaft speed rates and hence better transport efficiency, is explored for a modern 3600 TEU container vessel with the aim of fitting an 13 % larger diameter propeller (and hence resulting 20% lower rpm) to gain further power saving over the similar size basis container ship with conventional "level keel" configuration. It appears that successful application of the "inclined keel Hull" concept is a fine balance amongst the maximum gain in propulsive efficiency, minimum increase in hull resistance and satisfaction of other naval architectural and operational requirements. In order to make the concept economically more viable, this paper concentrates on the fore body design with the possible combination of increase of volume in its fore body to recover the expected volume loss in the aft body due to the space for larger propeller and its low wave-making resistance to minimize the efficiency loss using a well-established optimization software.

• Journal of the Korean Society of Systems Engineering
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• 제4권1호
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• pp.35-43
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• 2008

Generally, in analysis of reliability of Design and Development Phase, reliability of electrical components is analyzed based on standards such as MIL-HDBK-217F, Bellcore Issue 4,5,6 by analyzing stress of architectural side (Power, Voltage, Current and quality level of components) of weapon system and stress of operational side (operational environment, operational temperature, Operational Profile). But the reliability of mechanical components is analyzed based on the data book of failure history of mechanical parts called NPRD-95(Nonelectronic Parts Reliability Data-95) without any analysis of above stress. However, even if it's the same mechanical parts, it might have different failure rate(fatigue, wear, corrosion) during operation depending on how weary(stress : pressure, vibration, temperature during operation) the parts are. Therefore, analyzing reliability using just data book can cause big difference in reliability instead of analyzing based upon stressfulness that parts might have, operational concept, and other various factors. Thus, This paper will guide the way of predicting reliability by organizing ways of predicting reliability for system organization and adopt ing NSWC-98/LE1(Naval Surface Warfare Center-98/LE1) for mechanical components.

• Journal of Advanced Navigation Technology
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• 제27권1호
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• pp.119-125
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• 2023

It is necessary to reduce aviation GHG(CO2) emission to ensure aviation sustainable development. Operational improvements may not contribute significantly to carbon reduction but it can sustatially reduce emission in a short term. ICAO has developed GANP and ASBU to optimize operations and countries are making efforts to expand infrastructure and develop technology. The legal barriers to operational improvement are based on the notion of state sovereignty under the Chicago Convention which allows countries to control inefficiencies based on borders or limit or prohibit the passage of aircraft. Chicago Convention does not grant unlimited freedom of air sovereignty and if the concept of state sovereignty is interpreted according to the times it is possible to achieve smooth operational improvement.

• Journal of Technology Innovation
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• 제28권4호
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• pp.27-62
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• 2020

This study empirically verified the effect of environmental dynamism on changes in the dynamic and operational capabilities of an enterprise and its innovation performance. With the aim of quantification, the concept and definition of each capability were defined as a hierarchical structure of dynamic and operational capabilities. Five research hypotheses were established through prior research on dynamic capabilities, operational capabilities, innovation performance, and environmental dynamism. For empirical analysis, the hypotheses were verified based on surveys from 300 Korean manufacturing companies. It was shown that Dynamic capabilities had a positive relationship with operational capabilities and operational capabilities had a positive relationship with innovation performance. And it was shown that operational capabilities had a positive relationship with radical innovation in business groups with high environmental dynamism while operating capabilities had a positive relationship with gradual innovation in business groups with low environmental dynamism. Also, the moderating effect of environmental dynamism was not significant in the relationship with dynamic capabilities on operational capabilities. This study is meaningful in that it lays the groundwork for empirically verifying the dynamic capabilities of an enterprise by embodying its dynamic capabilities and operational capabilities into processes, and verifies the effect of environmental change on its capabilities and innovation performance. And it has implications to suggest how an enterprise should transform its capabilities to sustain its competitive advantage in a rapidly changing environment.