• Journal of the Korean Society of Propulsion Engineers
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• 제16권6호
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• pp.41-47
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• 2012

It is very important to predict the nonlinear behavior of combustion instability such as transition phenomena and limit cycle amplitude for fully understanding and controlling the instabilities. These nonlinear instability characteristics are highly dependent upon the flames' nonlinear dynamics in a gas turbine premixed combustor. In this study, nonlinear instability TA(Thermo-acoustic) models were introduced by applying the concept of flame describing function to the thermoacoustic analysis method. As a result of model development, for a given combustor length, the growth rate of instability was greatly affected by the change in amplitude, although the instability frequency was not. Further researches under various operating conditions and model validation on limit cycle amplitude are required.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제21권2호
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• pp.74-84
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• 2022

Vehicle average speed information which measured at a point or a short section has a problem in that it cannot accurately provide the speed changes on an actual highway. In this study, segment separation method based on vehicle big data for accurate micro-speed estimation is proposed. In this study, to find the point where the speed deviation occurs using location-based individual vehicle big data, time and space mean speed functions were used. Next, points being changed micro-scale speed are classified through gradual segment separation based on geohash. By the comparative evaluation for the results, this study presents that the link-based speed is could not represent accurate speed for micro-scale segments.

• Journal of Convergence for Information Technology
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• 제8권1호
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• pp.95-103
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• 2018

This study set out to evaluate the fitness of shelter locations by taking into consideration service zones according to walking speed, the changing population between day and night, and walking routes. Walking speed was defined as 1.6 m/s, 2 m/s based on the cases of previous studies. The changing population between day and night was estimated with the dasymetric mapping technique. Shelter service zones according to walking speed and routes were analyzed with the network of the location allocation model. The findings show some shelters had limits with their capacity according to the changing floating population and walking speed in time and space and raise a need to appoint additional shelters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.350-353
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• 2014

The large scale of data and operating systems in the trading environment in the cloud. However, technology is not an easy trading system of cloud-based data interoperability. Partially meets the data transfer rate and also the timeliness of the best trading system on the difficulties. Thus various techniques have been introduced for improving the throughput and low latency minimization problem. But the reality is, and the limits of speed improvements like Socket Direct Protocol, Offload Engine with TCP/IP is the hardware, the introduction effect is also low. In this paper, the proposed trading of the cloud XMDR-DAI based stock system. The proposed Safe Proper Time Method for optimal transmission speed and reliability.

• Journal of Biomedical Engineering Research
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• 제24권2호
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• pp.121-126
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• 2003

The purpose of this work was to assess and quantify whether the beneficial effects in long-term gas exchange at exciting frequency were obtained at different frequencies as well and then to develop a vibrating intravascular lung assist device(VIVLAD), for Patients suffering from acute respiratory distress syndrome(ARDS) or chronic respiratory problems. We investigate the optimal condition of the frequency band excited with new vibrator at state of limit hemolysis when blood hemolysis came to through a membrane vibration action. The experimental design and procedures were given for a device used to assess the effectiveness of membrane vibrations. Quantitative experimental measurements were performed to evaluate the performance of the device . and to identify membrane vibration dependence on blood hemolysis. We developed an analytical solution for the hydrodynamics of flow through a bundle of sinusoidally vibrated hollow fibers that is used to provide some insight into how wall vibrations might enhance the performance of the VIVLAD. In the result, it was measured that the effect of various excited frequencies in gas transfer rate and hemolysis from the maximum gas transfer rate at no vibration when the maximum gas transfer rates showed at module type 6, module type 6 consisted of 675 hollow fiber membranes The maximum oxygen transfer rate was caused by the occurrence of maximum amplitude and transfer of vibration to hollow fiber membranes when it was excited by the frequency band of 7Hz at each blood flow rate. because this frequency became the End mode resonance frequency of the flexible in blood flow. Also, when module type 6 was excited at an excited frequency of 7Hz. blood hemolysis was low. Therefore, we decided that the limit of hemolysis frequency is 7Hz . because maximum amplitude occurred at this frequency.

• Cross-Cultural Studies
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• 제43권
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• pp.377-404
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• 2016

In this paper, I intend to focus on the 1991 racial tension and violence portrayed in Anna Devear Smith's book Fires in the Mirror, which was published in book form in 1993. I make use of a series of interviews with many of those involved in the conflicts, which were based on the Jewish Holocaust and the history of African American enslavement. In Crown Heights, the black community and the Jewish community have each suffered terrible losses, but individuals and communities become rhetorically attached to foundational historical traumas that lie at the center of each group's cultural identity rather than try to understand each other's pain. Smith lets this rhetoric dominate Fires in the Mirror by putting contradictory monologues side by side in order to show how discourses on 'slavery' and 'the Holocaust' still have control over specific ethnic communities. My intention is not to delve into the conflict between the Jewish and black communities exclusively. Rather, I attempt to form an understanding of the problems of the critical/theoretical tenets proposed by 'the rhetoric of holocaust,' including the Jewish Holocaust and the black experience of enslavement. Such an understanding will help us see the failure in the theories, illuminating the ways that such rhetoric should have recognized its own violence and helped to forge a new relationship between racism and anti-Semitism. Fires in the Mirror mirrors back to us the ways that 'the Holocaust' betrays the possibility of error to indicate its own susceptibility to blindness. The cracks brought forth by conflicting narratives enable readers to observe wounds being healed and the possibility of new narrative looming up.

• Journal of the Korean Geotechnical Society
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• 제23권2호
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• pp.71-83
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• 2007

Liquefaction resistance depends strongly upon the degree of saturation, which is expressed in terms of the pore pressure coefficient, B. The B-value has been widely used to quantify the state of saturation of laboratory samples. However, it is practically impossible to determine in situ state of saturation by using the B-value. So, P-wave velocity can be alternatively used as a convenient index for evaluating the in situ state of saturation. In this paper, the Stokoe type torsional shear (TS) testing system was modified to saturate the specimen, with which it is also possible to measure P ($V_p$), S-wave velocity ($V_s$) and the excess pore water pressure buildup In order to examine the effect of B-value for nearly saturated sands. A series of the tests were carried out at 3 relative densities (40%, 50% and 75%) and various B-values using Toyoura sand. Based on the test results, the variations of $V_p\;and\;V_s$ with B-value were analyzed and compared with a existing theoretically derived formula. The normalized pore water pressure, $du/{\sigma}{_0}'$ and cyclic threshold shear strain, ${\gamma}^c_{th}$ with B-value were also analyzed. Additionally the test results related to pore water pressure were analyzed by $V_p$ to apply to the field seismic analysis.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제2권
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• pp.183-190
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• 1994

본 연구에서는 항공기 사고의 대부분을 차지하는 이${\cdot}$착륙단계중에서, 이륙직 후 저고도에서 동력이 상실되었을 경우에 이륙활주로 방향으로 Turning Back하는 것은, 어떠한 안전 한계를 지니고 있는지를 선회 소요시간과 고도손실, 선회율과 활공속도와의 관계 등의 이론적인 근거에 기초하여 분석하고자 한다.

• The Korean Publising Journal, Monthly
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• 통권223호
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• pp.18-19
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• 1997

올 가을 출판계에 문학평론집의 작황이 풍성하다. 이들 평론집은 우리 문학과 작가들이 더이상 이 시대의 위기 속에서 안전하지 않다는 첨예한 문제의식을 담고 있다. 미시적인 현장비평에서 거시적 담론에 이르기까지 90년대 문학환경에 대한 자기반성이 적극적인 발언으로 표출되고 있다.

• Bulletin of Korea Environmental Preservation Association
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• 통권408호
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• pp.9-11
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• 2013

우리의 생활공간에서 실내공기, 소음, 전자파 등 생활공해로 인한 피해는 시시각각으로 일어나고 있다. 그 동안 깨끗하고 쾌적한 실내환경과 정온한 생활환경 속에서 모든 국민이 건강하게 생활할 수 있도록 다양한 생활환경관리 정책을 추진해 왔다. 하지만, 정부의 노력만으로는 한계가 있다. 국민이 편안한 생활환경의 창출을 위해서는 그 구성원의 자발적인 노력과 참여가 필요하다.