• Title/Summary/Keyword: wave-train

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Investigation on Characteristics of Summertime Extreme Temperature Events Occurred in South Korea Using Self-Organizing Map (자기조직화지도(Self-Organizing Map)를 이용한 최근 우리나라 여름철 극한온도 특성 분류)

  • Lim, Won-Il;Seo, Kyong-Hwan
    • Atmosphere
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    • v.28 no.3
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    • pp.305-315
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    • 2018
  • This study investigates the characteristic spatial patterns and dynamic processes associated with the summertime extreme temperature events in South Korea during the last 20 years (1995~2014) using Self-Organizing Map (SOM). The classified SOM patterns commonly have high temperature and anticyclonic circulation anomalies over South Korea. The two major teleconnection patterns are identified: one is from the subtropical western North Pacific (WNP) affecting to the north and the other is from the North Atlantic (NA) affecting downstream region. The meridional teleconnection pattern is related to the forcing of positive sea surface temperature (SST) anomaly over the WNP. The northward propagating Rossby wave generates the East Asia-Pacific (EAP) pattern to form an anticyclonic circulation anomaly over South Korea. On the other hand, NA SST anomalies generate an eastward Rossby wave train across the Eurasian continent, leading to the development of an anticyclonic circulation anomaly over South Korea. The EAP pattern occurs more frequently in July and August, whereas the midlatitude teleconnection pattern associated with NA SST anomalies develops more frequently in early summer (June).

New Gain Function Based on Attenuation Characteristics of Ballast Track for GPR Analysis (GPR 분석을 위한 자갈궤도 자갈의 감쇄특성을 이용한 이득함수 개발)

  • Shin, Jihoon;Choi, Yeongtae;Jang, SeungYup
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.4
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    • pp.13-21
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    • 2017
  • Ballasted track has been used as track system for more than 100 years. Ballasted track has advantages of low construction cost, flexible maintenance, low noise and vibration, and so on. However, ballasted track leads to continuous settlement which causes maintenance. Recently, increase in speed, traffic volume, and weight of train requires more frequent maintenance. Fouling, well-known phenomenon of accumulation of fine materials due to intrusion of subgrade and breakage of ballast materials, expedites the settlement (i.e., irregular settlement) of track. Ground Penetrating Radar (GPR) can be one of non-destructive tools that can evaluate fouling level of ballast. In this paper, a gain function based on the attenuation characteristics of ballast material is suggested in conjunction with Hilbert transform. Lab box tests and full-scale tests indicate that the suggested method reasonably classifies clean, fouled layers, and subgrade. However, additional study to eliminate effect of sleeper and to include the scattering features of the electromagnetic wave in ballast voids should be required in order to enhance the accuracy.

A Study on Suitability of Training Facilities and Equipment used on Seafarer's Sea Survival Training (선원 해상생존교육 실습시설 및 장비의 적정성에 관한 연구)

  • Lee, Jin-Woo;Kim, E-Wan;Lee, Chang-Hee;Lee, Young-Ho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.5
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    • pp.473-481
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    • 2017
  • Seafarer sea survival training, such as basic safety refresher training and advanced safety refresher training, in accordance with the STCW Convention, is an indispensable program that can increase the crew survival rate during emergency situations at sea. It is important for crew members to carry out theoretical and practical training with various safety equipment in order to effectively train according to IMO model courses. Therefore, this study suggests the following measures to improve safety training facilities for seafarers by reviewing survival training requirements based on the IMO model course and comparing and analyzing related facilities based on operating cases from domestic and overseas training institutes. First, it is necessary to establish a training environment where seafarers can practice utilizing various, updated safety equipment such as marine evacuation equipment (slides, chutes, etc.). Second, it is necessary to construct an educational environment in which learners can directly or indirectly experience realistic emergency situations by installing marine environment simulation facilities with such equipment as a wave generator, rain fall device, wind generating device, etc. Third, it is also necessary to develop and expand customized training using virtual reality equipment in addition to experiential training, audiovisual training and simulation training.

Analysis of Mechanical Behavior of Existing Tunnel by the Construction of Shaft Nearby (근접한 수직구 건설에 따른 기존 터널의 역학적 거동 분석)

  • 이석원;조만섭;이성원
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.109-122
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    • 2003
  • In order to release the pressure fluctuations and micro-pressure wave induced by the entering of train into the small cross sectional tunnel, it has been reported that the construction of air shaft has more advantages with respect to economy and constructability than the enlargement of cross section of existing tunnel. The field monitorings and analytical studies were conducted simultaneously in this study to analyze the mechanical behavior of existing railway tunnel, new cross tunnel and new shaft by the construction of new shaft nearby. The results showed that the minimum distance from existing tunnel to new shaft which secures the stability of existing tunnel was found to be half diameter of existing tunnel. On the three dimensional mechanical behavior of existing tunnel by the construction of new shaft, the results from the analytical study and field monitoring had a similar trend. The analytical study and field monitoring results, however, produced somewhat different results on the mechanical behavior of new shaft itself. These conclusions induce that the analytical method which has been applied on the analyses of horizontal tunnel could not be applied in the same way on the analysis of vertical shaft.

A Study on the Effect of Superleadership of Small and Medium Enterprises on Business Performances (중소기업의 슈퍼리더십이 경영성과에 미치는 영향 연구)

  • Park, Cheol Woo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.12 no.4
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    • pp.175-189
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    • 2017
  • Science and technologies develop rapidly and in conditions where it is difficult to predict both domestically and abroad, the rapidly changing business environment demands innovation. To strengthen the businesses' competitive edge, the key challenge is not to control but rather grant autonomy, allowing it to anticipate the future and actively deal with. This will allow to train and manage talented people with competence and abilities, which all links to the concept of the Super Leadership. Currently, our society is in the change due to the Fourth Industrial Revolution wave and paradigm related with high-tech industry, hence is in desperate need for creativeness and speed management. It is a time where risk and challenges coexist and is not a standardized environment. Businesses must make efforts in managing human resources and allow them to have leaderships compatible with the current era, giving them opportunities to face challenges. The necessity for Super Leadership is emphasized especially in the industry-orientated era, where new revolutionary technologies are emerging and existing technologies are being advanced and maximized, to cultivate the potentials of the members and secure competitive superiority for the best management and creation. Therefore, in this research, the empirical analysis of the relationship between Super Leadership of small and medium enterprises and the business outcome was conducted. Research outcome states that, in order to create a sustainable business outcome, enterprises need to invest more in developing leaderships and in accordance with it, promote talent. In order to survive and sustain growth in the period of endless competition like today, it is concluded that it is imperative to establish a powerful Super Leadership that will endeavor to engage and maximize the competence of members of the organization.

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Neural Network-Based Prediction of Dynamic Properties (인공신경망을 활용한 동적 물성치 산정 연구)

  • Min, Dae-Hong;Kim, YoungSeok;Kim, Sewon;Choi, Hyun-Jun;Yoon, Hyung-Koo
    • Journal of the Korean Geotechnical Society
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    • v.39 no.12
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    • pp.37-46
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    • 2023
  • Dynamic soil properties are essential factors for predicting the detailed behavior of the ground. However, there are limitations to gathering soil samples and performing additional experiments. In this study, we used an artificial neural network (ANN) to predict dynamic soil properties based on static soil properties. The selected static soil properties were soil cohesion, internal friction angle, porosity, specific gravity, and uniaxial compressive strength, whereas the compressional and shear wave velocities were determined for the dynamic soil properties. The Levenberg-Marquardt and Bayesian regularization methods were used to enhance the reliability of the ANN results, and the reliability associated with each optimization method was compared. The accuracy of the ANN model was represented by the coefficient of determination, which was greater than 0.9 in the training and testing phases, indicating that the proposed ANN model exhibits high reliability. Further, the reliability of the output values was verified with new input data, and the results showed high accuracy.

Culture and Art Policies of Korean government for Traditional Dancing Digital Contents (전통춤 디지털 콘텐츠에 관한 문화예술정책 연구)

  • Kim, Ji-Won;Rhyu, Ji-Sung
    • The Journal of the Korea Contents Association
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    • v.12 no.9
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    • pp.156-171
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    • 2012
  • It is the time of the Korean Wave booming throughout the world, placing Korean culture in the center of the world and its added value is unaccountable. At this prosperity, the preserving of the archetype of Korean dancing and digital contents making is becoming a task not only for the government but also for the private sector because culture industry has enormous added values. To achieve such goals, contents development is an urgent matter but establishing the value of the archetype of Korean traditional dancing must have priority. The public has to take an active role in rediscovering the values of traditional culture, and as the representative of Korean identity traditional dancing must be the object of a systematic art policy. This study will review the current status of 'digital contents program of the archetype of culture' for traditional dancing and will reconsider the modern value of preserving the archetype of culture to make a suggestion to the direction of culture art policies in the near future. The study acknowledged the lack of technical personnel majoring in the archetype of traditional dancing and the need of reviewing the credibility of historical research procedures. Even with the studies by industry-university collaboration and positioning of specialists, effective policies that will form the foundation for private firms to train personnels is in urgent need. In other words, training personnels, allocation of resource, securing funds, policies promoting collaboration between private and individual businesses, and the commercial recognition at private firms are still far from establishing. This is due to the fact that archetype of culture is not a business that creates revenue immediately, therefore the recognition of traditional dancing as an investable item by business-oriented firms or movements are difficult to find. To overcome such situation, software oriented policies that establish open communication and sharing with the public should be done at first rather than the quantity oriented hardware policies of contents development. Through this process the public can change the attitude on traditional dancing and traditional dancing could be newly recognized as a creative repository of culture and as public businesses giving birth to economic value.