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A Study on the Relationship between Ship Stability and Maneuverability Using Free Running Model Experiments (자유항주 모형실험에 의한 선박의 복원성능과 조종성능 관계 연구)

  • Choe, Bo-Ra;IM, Nam-Kyun
    • Journal of Navigation and Port Research
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    • v.40 no.6
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    • pp.353-360
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    • 2016
  • The International Maritime Organization (IMO) has issued international standards for ship maneuverability and stability. These have been established to improve marine safety and influence the direction of research. The previous literature has been researched, but there are few studies on the relationship between ship maneuverability and stability. This study carried out a fundamental experiment to quantitatively evaluate that relationship. Radius of turn and maximum heel angle depending on changing were analyzed through a turning test using a free running model ship. The test results show the change tendency of decreasing turn radius and increasng maximum heel angle according to a GM decrease. A rough estimate equation is proposed to predict the change tendency on radius of turn and angle of maximum heel as GM decreases. Many ships can suddenly experience reduced GM due to unexpected reasons during sailing. The results in this study can be used as fundamental data to estimate a ship's tactical turn diameter and variable heel angle for steering as GM decreases.

Research and Development Trends of a Hypersonic Glide Vehicle (HGV) (극초음속 활공 비행체(HGV)의 연구개발 동향)

  • Hwang, Ki-Young;Huh, Hwanil
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.9
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    • pp.731-743
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    • 2020
  • The hypersonic glide vehicle ascends to a high altitude by a rocket booster, separates it from the booster, and glides at a hypersonic speed of Mach 5 or higher at an altitude of about 30~70 km, changing its direction in the atmosphere. Since it moves on an unpredictable flight path rather than a parabolic trajectory, it is difficult to intercept with current missile defense systems. The U.S. conducted HTV-2 and AHW flight tests in the early 2010s to confirm the possibility of hypersonic gliding flights, and recently it has been developing hypersonic glide vehicle systems such as LRHW and ARRW. China has conducted several flight tests of the DF-ZF (WU-14) glide vehicle since 2014 and has been operating it with DF-17 missiles. Russia has conducted hypersonic glide vehicle research since the former Soviet Union, but it has repeatedly failed, and recently it has been successfully tested with the Avangard (Yu-71) glide vehicle mounted on the SS-19 ICBM. In this paper, the characteristics, flight test cases, and development trends of hypersonic glide vehicles developed or currently being developed in the United States, China, Russia, Japan, India, and Europe are reviewed and summarized.

Entrepreneurial Universities Case Study: Based on Ambidextrous Strategy (기업가형 대학의 사례 연구: 양손잡이 전략 관점으로)

  • Won, Chi Un;Bae, Tae Jun;Choi, Kyung Chul
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.4
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    • pp.27-43
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    • 2020
  • Recently, there has been growing interest in entrepreneurial universities. Accordingly, this study discussed the paradigm shift from traditional university roles to entrepreneurial universities and conducted case analysis of Oxford University, Stanford University and Berlin Institute of Technology from the perspective of ambidextrous strategies of universities. Universities are emphasizing the importance of academic capitalism through market activities as well as the educational and research-oriented role to adapt and survive the rapidly changing uncertain environment. Therefore, many studies related to this have been conducted. This paper discusses the background and necessity of the transformation from traditional universities to entrepreneurial universities, and applies the case of a university that has been successful in transforming into an entrepreneurial universities and creating excellent outcome in terms of ambidextrous strategy. Specifically, this study examined the structural, contextual, and leadership perspectives as a antecedents for ambidextrous strategy. This paper expects not only to introduce cases but also to be used as reference for adapting to future paradigm shifts to entrepreneurial universities and setting the direction of universities.

Evidence for Hydrothermal Plume in Manus Basin, SW Pacific: Distribution of Transparency and Hydrogen Sulfide (남서태평양 마누스분지 해역의 열수 plume 증거: 투명도 및 황화수소 분포)

  • Lee, Kyeong-Yong;Park, Yong-Chul;Son, Seung-Kyu
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.4
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    • pp.363-373
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    • 2000
  • To understand and investigate chemical characteristics of thermal environment in the southwestern Paciflc, we have measured hydrological and chemical parameters such as temperature, salinity, transparency, pH, nutrients and hydrogen sulfide (H$_2$S). Samples were collected with CTD-casting at 12 station, in Manus Basin including PACMANUS, DESMOS and Susu Knolls, Hydrothermal systems consist of circulation zones where seawater interacts with rock, thereby changing chemical and physical characteristics of both the seawater and the rock. The altered seawater, called hydrothermal fluid, is injected back into the ocean from the hydrothermal vent fields and forms hydrothermal plumes. Consequently, we detected hydrothermal plume with transparency and sulfide anomalies at PACMANUS and Susu Knolls. Sulfide, as geochemical tracer of hydrothermal plume, ranged 0-3.31 ${\mu}$M, and averaged 0.63 ${\mu}$M in the study area. The height, flux and activity of the plume are affected by circulations in the deep water and the spread of plume follows along the isopycnal surface. Therefore the observed H$_2$S anomaly can provide important clue for the source location and it appears that the targestsource in the PACMANUS is aligned in the north-south direction.

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Reliability Analysis of Wave Overtopping over a Seawall (호안에서의 월파에 대한 신뢰성 해석)

  • Oh Jung-Eun;Suh Kyung-Duck;Kweon Hyuck-Min
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.18 no.1
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    • pp.69-83
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    • 2006
  • A Level 3 reliability analysis has been performed for wave run-up and overtopping on a sloping seawall. A Monte-Carlo simulation was performed considering the uncertainties of various variables affecting the wave overtopping event. The wave overtopping probability was evaluated from the individual wave run-up by using the wave-by-wave method, while the mean overtopping rate was calculated directly from the significant wave height. Using the calculated overtopping probability and mean overtopping rate, the maximum overtopping volume was also calculated on the assumption of two-parameter Weibull distribution of individual wave overtopping volume. In addition, by changing wave directions, depths, and structure slopes, their effects on wave overtopping were analyzed. It was found that, when the variability of wave directions is considered or the water depth decreases toward shore, wave height become smaller due to wave refraction, which yields smaller mean overtopping rate, overtopping probability and maximum overtopping volume. For the same mean overtopping rate, the expected overtopping probability increases and the expected maximum overtopping volume decreases as approaching toward shore inside surfzone.

Evaluation of Correlations in Copier's Button and Usability (복사기 조작버튼에 따른 사용성 상관관계 연구)

  • Ha, Kwang Soo
    • The Journal of the Korea Contents Association
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    • v.13 no.12
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    • pp.595-603
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    • 2013
  • Touchscreen is now installed in the majority of information devices thanks to the developed digital technology. In case of copiers, although touchscreen was installed earlier than any other information device, current user interface indicates that conventional methods have been maintained without any special re-validation. But, since common office devices such as copiers have brief usage time and clear, straightforward purposes, user experience between an user and device is perhaps an important element. Nevertheless, conservativeness of the market and the fact that users and buyers are not always the same are a stumbling block to actively changing UI. Recently, however, as hardware element, buttons, have moved to touchscreen mostly for smartphone, and common and public devices have seen rapid changes in UX, mostly with touchscreen, it has led to high demand for changes in UX of copiers. To remedy the issues with copiers, a literature review was conducted through existing studies and user evaluation based on user survey and prototype was done to examine the copier's UI elements and relevant changes in usage. In particular, a new direction for UX of copiers was suggested by analyzing the impact of differences between software button-oriented UI and hardware button-oriented UI on users and usability. This study findings could be used as basic data for improving the usability of future common devices including copier and UX design.

A Case Study for Simulation of a Debris Flow with DEBRIS-2D at Inje, Korea (DEBRIS-2D를 이용한 인제지역 토석류 산사태 거동모사 사례 연구)

  • Chae, Byung-Gon;Liu, Ko-Fei;Kim, Man-Il
    • The Journal of Engineering Geology
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    • v.20 no.3
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    • pp.231-242
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    • 2010
  • In order to assess applicability of debris flow simulation on natural terrain in Korea, this study introduced the DEBRIS-2D program which had been developed by Liu and Huang (2006). For simulation of large debris flows composed of fine and coarse materials, DEBRIS-2D was developed using the constitutive relation proposed by Julien and Lan (1991). Based on the theory of DEBRIS-2D, this study selected a valley where a large debris flow was occurred on July 16th, 2006 at Deoksanri, Inje county, Korea. The simulation results show that all mass were already flowed into the stream at 10 minutes after starting. In 10minutes, the debris flow reached the first geological turn and an open area, resulting in slow velocity and changing its flow direction. After that, debris flow started accelerating again and it reached the village after 40 minutes. The maximum velocity is rather low between 1 m/sec and 2 m/sec. This is the reason why debris flow took 50 minutes to reach the village. The depth change of debris flow shows enormous effect of the valley shape. The simulated result is very similar to what happened in the field. It means that DEBRIS-2D program can be applied to the geologic and topographic conditions in Korea without large modification of analysis algorithm. However, it is necessary to determine optimal reference values of Korean geologic and topographic properties for more reliable simulation of debris flows.

A Study on the Multi-function Furniture Design Concept for the 'Singles' (싱글족을 위한 다기능 가구 디자인 컨셉연구)

  • Wu, Shi Lin;Lee, Bo-Bae
    • The Journal of the Korea Contents Association
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    • v.14 no.2
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    • pp.103-112
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    • 2014
  • With the development of the society, people's thought and the way of life is changing. The change of the traditional values and marriage lead to the increase of the "singles" groups in modern society. The "singles" group's behaviors, living environment, and consumption have become a social focus. With the emergence of the "singles", traditional furniture already can't meet the demand, so personalized furniture should be developed for the "singles". This study based on background and consumption psychology of the "singles", analyzed the consumption characteristics and preferences of the "singles". It studied the furniture demand of the "singles", and analyzed the existing unmarried person's residential form, types and characteristics of the furniture, and also analyzed the existing furniture using by the "singles" with SWOT, made a more systematic study for finding the advantages and disadvantages of existing the "singles" group's furniture. Then, combined with the unmarried person's furniture needs, living forms, the advantages and disadvantages of the "singles" furniture, etc., made the multi-functional furniture design concept for the "singles". This concept as a design direction, which would make out more suitable furniture be in keeping with the "singles" group's characteristics and requirements. Finally through the concept of multi-functional and folding raise the utilization ratio of narrow space of the living environment.

Self-reflexivity in Animation Media -focusing on exposure of production process and intertexuality- (애니메이션의 매체적 자기반영성 -생산과정의 노출과 상호텍스트성을 중심으로-)

  • Suh., Yong
    • Cartoon and Animation Studies
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    • s.34
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    • pp.81-104
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    • 2014
  • Self-reflexivity means consciousness turning back on itself and breaks with art as illusionism and exposes their own factitiousness as textual construct. Self-reflexivity in media deals with the media's condition and process itself and tends to pull viewers out of the reality represented on screen by reminding them that is a media's construction or illusion on the screen. Representation aesthetics has been recognized with an essential theory of the art since Ancient Greek, but it has encountered crisis with the invention of the photography and the cinema in the early 1900s. The supreme transparency of the new media induced a new perspective for the representation aesthetics, which had dominated the art world. The art derived from the representation stood on the crossroad of changing direction. Modernism aesthetics wanted to search for the self-referentiality in order to the replace the past principal. This essay focuses on self-reflexivity in animation and their methodology. First, the change of representation aesthetics in visual arts will be discussed. Second, animations exposing their process of production and components will be analyzed, and lastly, intertextuality in animation will be dealt. I hope to provide the vision of the expanded animation media with this study.

Motility Analysis of Gate Myocardium SPECT Image Using Left Ventricle Myocardium Model (좌심실 심근 모델을 이용한 게이트 심근 SPECT 영상의 운동성 분석)

  • 손병환;김재영;이병일;이동수;최흥국
    • Journal of Korea Multimedia Society
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    • v.6 no.3
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    • pp.444-454
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    • 2003
  • An analysis of heart movement is to estimate a role which supplies blood in human body. We have constructed a left ventricle myocardium model and mathematically evaluated the motion of myocardium. The myocardial motility was visualized using some parameters about cardiac motion. We applied the myocardium model in the gated myocardium SPECT image that showed a cardiac biochemical reaction, and analyzed a motility between the gated myocardium SPECT image and the myocardium model. The myocardium model was created of the based on three dimensional super-ellipsoidal model that was using the sinusoidal function. To express a similar form and motion of the left ventricle myocardium, we calculated parameter functions that gave the changing of motion and form. The LSF algorithm was applied to the myocardium gated SPECT image data and the myocardium model, and finally created a fitting model. Then we analyzed a regional motility direction and size of the gated myocardium SPECT image that was constructed on a fitting model. Furthermore, we implemented the Bull's Eye map that had evaluated the heart function for presentation of regional motility. Using myocardium's motion the evaluation of cardiac function of SPECT was estimated by a contraction ability, perfusion etc. However, it is not any estimation about motility. So, We analyzed the myocardium SPECT's motility of utilizing the myocardium model. We expect that the proposed algorithm should be a useful guideline in the heart functional estimation.

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