• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.848-853
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• 2004

Regarding to the project SUAV (Smart Unmanned Aerial Vehicle) in KARI (Korea Aerospace Research Institute), several engine configurations has been evaluated. However it's not an easy task to collect all the necessary data of each engine for the analysis. Usually, some kind of modeling technique is required in order to determine the unknown data. In the present paper a qualitative method for reverse engineering is proposed, in order to identify some design patterns and relationships between parameters. The method can be used to estimate several parameters that usually are not provided by the manufacturer. The method consists of modeling an existing engine and through a simulation, compare its transient behavior with its operating envelope. In the simulation several parameters such as thermodynamics, performance, safety and mechanics concerning to the definition of operation-envelope, have been discussed qualitatively. With the model, all engine parameters can be estimated with acceptable accuracy, making possible the study of dependencies among different parameters such as power-turbine total inertia, TIT, take-off time and part load, in order to check if the engine transient performance is within the design criteria. For more realistic approach and more detailed design requirements, it will be necessary to enhance the compressor map first, and more realistic estimated values must be taken into account for intake-loss, bleed-air and auxiliary power extraction. The relative importance of these “unknown” parameters must be evaluated using sensitivity analysis in the future evaluation. Moreover, fluid dynamics, thermal analysis and stress analysis necessary for the resulting life assessment of en engine, will not be addressed here but in a future paper. With the methodology presented in the paper was possible to infer the relationships between operation-envelope and engine parameters.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.342-351
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• 2010

During the operation of a hydro turbine the fluid mechanical pressure loading on the turbine blades provides the driving torque on the turbine shaft. This fluid loading results in a structural load on the component which in turn causes the turbine blade to deflect. Classically, these mechanical stresses and deflections are calculated by means of finite element analysis (FEA) which applies the pressure distribution on the blade surface calculated by computational fluid dynamics (CFD) as a major boundary condition. Such an approach can be seen as a one-way coupled simulation of the fluid structure interaction (FSI) problem. In this analysis the reverse influence of the deformation on the fluid is generally neglected. Especially in axial machines the blade deformation can result in a significant impact on the turbine performance. The present paper analyzes this influence by means of fully two-way coupled FSI simulations of a propeller turbine utilizing two different approaches. The configuration has been simulated by coupling the two commercial solvers ANSYS CFX for the fluid mechanical simulation with ANSYS Classic for the structure mechanical simulation. A detailed comparison of the results for various blade stiffness by means of changing Young's Modulus are presented. The influence of the blade deformation on the runner discharge and performance will be discussed and shows for the configuration investigated no significant influence under normal structural conditions. This study also highlights that a two-way coupled fluid structure interaction simulation of a real engineering configuration is still a challenging task for today's commercially available simulation tools.

• 동력기계공학회지
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• 제18권6호
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• pp.180-185
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• 2014

Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it's being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.

• Wind and Structures
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• 제29권5호
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• pp.339-359
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• 2019

Pre-stressed concrete poles are among the supporting systems used to support transmission lines. It is essential to protect transmission line systems from harsh environmental attacks such as downburst wind events. Typically, these poles are designed to resist synoptic wind loading as current codes do not address high wind events in the form of downbursts. In the current study, the behavior of guyed pre-stressed concrete Transmission lines is studied under downburst loads. To the best of the authors' knowledge, this study is the first investigation to assess the behaviour of guyed pre-stressed concrete poles under downburst events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, an in-house built numerical model is developed incorporating the following: (1) a three-dimensional downburst wind field previously developed and validated using computational fluid dynamics simulations; (2) a computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors including the effects of the pretension force, sagging, insulator's stiffness and the non-uniform distribution of wind loads, and (3) a non-linear finite element model utilized to simulate the structural behaviour of the guyed pre-stressed concrete pole considering material nonlinearity. A parametric study is conducted by varying the downbursts locations relative to the guyed pole while considering three different span values. The results of this parametric study are utilized to identify critical downburst configurations leading to peak straining actions on the pole and the guys. This is followed by comparing the obtained critical load cases to new load cases proposed to ASCE-74 loading committee. A non-linear failure analysis is then conducted for the three considered guyed pre-stressed concrete transmission line systems to determine the downburst jet velocity at which the pole systems fail.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.407-407
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• 2019

According to Asian Development Bank report Pakistan is among water scarce countries. Climate scenario on the basis IPCC fifth assessment report (AR5) revealed that annual mean temperature of Pakistan from year 2010-2019 was $17C^o$ which will rise up to $21C^o$ at the end of this century, similarly almost 10% decrease of annual rainfall is expected at the end of the century. It is a changing task in underdeveloped countries like Pakistan to meet the water demands of rapidly increasing population in a changing climate. While many studies have tackled scarcity and stream flow forecasting of the Upper Indus Basin (UIB) Pakistan, very few of them are related to socio-economic and climate change impact on sustainable water management of UIB. This study investigates the pattern of current and future surface water availability for various demand sites (e.g. domestic, agriculture and industrial) under different socio-economic and climate change scenarios in Upper Indus Basin (UIB) Pakistan for a period of 2010 to 2050. A state-of-the-art planning tool Water Evaluation and Planning (WEAP) is used to analyze the dynamics of current and future water demand. The stream flow data of five sub catchment (Astore, Gilgit, Hunza, Shigar and Shoyke) and entire UIB were calibrated and validated for the year of 2006 to 2011 using WEAP. The Nash Sutcliffe coefficient and coefficient of determination is achieved ranging from 0.63 to 0.92. The results indicate that unmet water demand is likely to increase severe threshold and the external driving forces e.g. socio-economic and climate change will create a gap between supply and demand of water.

• 이베로아메리카
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• 제23권2호
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• pp.273-307
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• 2021

The covid 19 pandemic led to an economic collapse and multiple impacts upon Argentina's labour dynamics. As well as in other parts of the region, falls in employment rates (both due to an increase in unemployment and significant withdrawals from the labour force) were combined with wage reductions for those who were able to keep their jobs. Thus, two important processes for the labour market complimented each other: a structural shock associated with a tasks automation as a reorganisation and substitution of factors, with a cyclical recession caused by the pandemic. The international experience shows the amplifying impact the latter has on the former, generating long-term consequences mainly in routine-intensive jobs. However, the knowledge-intensive services sector appears to be the most capable of cushioning the recessionary shock (both in terms of wages and labour absorption), even with nuances within the sector depending on the extent of the shutdown measures and its capability to switch to remote work. Finally, the task approach is decisive in capturing the ability to adapt both the cyclical and structural processes, absorbing a large part of the explanatory potential that sectoral classifications tend to bring about.

• 영어영문학
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• 제55권1호
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• pp.25-59
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• 2009

This study explores the characteristics of Elizabeth Bishop's poetry in comparison with the two of her closest friends and poets, Marianne Moore and Robert Lowell. Bishop's reputation has dramatically changed since her death. In the 1970s she was "a writer's writer's writer," and admired by a small group of poets or critics. Since 1990s, however, there has been a great shift in the evaluation of her poetry, which is so called "The Elizabeth Bishop Phenomenon." It does not seem to be an easy task to examine what has driven the phenomenon, and why she used to be a minor poet or "the most honored yet most elusive of poets" but now she has a widespread recognition by the academy and beyond it. The "intrinsic qualities" of Bishop's poetry, however, can be one of the main reasons why it took several decades for Bishop to become a central figure in the literary canon. Looking into her "intrinsic qualities," this paper discusses Bishop's "The Fish," "Roosters" through the Moore-Bishop relationship, and reads Bishop's "Armadillo" and "The Monument" through the Lowell-Bishop relationship. It also deals with letters, interviews, Moore's "The Fish," and Lowell's "Skunk Hour" and "For the Union Dead" to show the Bishop's deep and complex relationships with the two poets, and more importantly their differences. Bishop's poetry is difficult, "elusive," and sometimes "enigmatic," not because her texts are full of difficult words to understand but because there are the subtle interchange between perception and meaning, "the dynamics of keen feeling," the unresolved patterns, and the transient vision under the seemingly transparent surface of the texts.

• 한국항행학회논문지
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• 제25권6호
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• pp.441-449
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• 2021

지능형 이동체 시스템 발달에 따라서, 보다 정확한 위치 정보 추정 기술에 대한 요구가 증가하고 있다. 특히, 실내에서 사용되는 이동 로봇에게 주어진 일을 정해진 위치에서 수행할 때에는 보다 정확한 위치 추정에 대한 성능을 필요로 한다. 따라서, 이 논문에서는 고정형 또는 이동형 사물에 적용 가능한 진보된 위치 추정 방법을 제안한다. 제안 방법은 미리 설치된 블루투스 비콘 신호로부터 위치 추정 결과를 칼만 필터의 관찰 신호로 사용한다. 또한, 센서의 위치와 각도에 따라서 결정되는 각 방향의 중력 가속도를 추정하기 위해서, 롤(roll)과 피치(pitch) 각도를 먼저 계산하고, 이 결과를 자기장 센서 출력과 결합하여 요(Yaw) 각도를 추정함으로써,이동체의 진행 방향을 정확히 추정한다. 이를 기반으로 이동체의 제어 입력이 되는 가속도 신호를 정확히 계산함으로써, 칼만 필터의 성능을 향상시키는 방법을 제안한다. 제안 방법의 성능은 고정 상태와 이동 상태로 나누어 평균 위치 오차를 계산하여 기존의 칼만 필터와 비교시 위치 오차를 크게 향상시킴을 확인하였다.

• International Journal of Computer Science & Network Security
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• 제23권12호
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• pp.129-136
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• 2023

Professional self-determination of the individual is a complex and lengthy process of finding and realizing yourself in the profession. The main goal of professional self-determination is clarified. The basic concepts of readiness for professional self-determination of future specialists in the modern information society are revealed. The following approaches to the consideration of the concept of readiness are defined: functional-psychological, personal, activity-based. Based on the components of readiness identified by the researchers, it can be assumed that the structure of professional self-determination of the future specialist contains motivational, cognitive and activity components. Self-determination is defined as a multidimensional process that can be considered from different points of view: as a series of tasks, that society sets for the emerging individual, and which the individual must solve in a certain period. As a process of step-by-step decision-making, with the help of which the individual forms a balance between his desires and inclinations, on the one hand, and the needs of society, on the other; as a process of forming an individual lifestyle, part of which is professional activity. A number of tasks of professional self-determination of a future specialist in the information society are formulated. Diagnostic practices for determining the degree of readiness of future specialists for future professional success are characterized. Practices are developed as a basis for creating an individually oriented correctional and development program to promote the formation of future specialists' focus on future professional success. Their task is to ensure control over the dynamics of this process, assess the effectiveness of this career guidance work. Practices are aimed at identifying the degree of thorough knowledge of the conditions for achieving professional success in the chosen field of activity among future specialists.

• Ocean and Polar Research
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• 제30권4호
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• pp.427-444
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• 2008

The most important bases of maritime laws in China are laws enacted by Constitution, a legislative institution of National People's Congress and Legislation of NPC Standing Committee. However, in reality, the institution, which become the basis of Chinese marine policy and leads overall maritime affairs, is a State Council of the Chinese central government and many objects of our researches on Chinese marine policy and laws are composed centering on this administration law. Therefore, in understanding Chinese maritime laws, it becomes an important prerequisite to understand relevant laws (statutes), administration law, statutes of local province, mutual authority relationships of these legislative institutions, and interpretation authority regarding laws (statutes). In May 2003, Chinese State Council ratified and declared ${\ll}$Guideline of the national maritime economic development plan${\gg}$ and this is the first macroinstructive document enacted by the Chinese government for promoting maritime economy in integration development. This plan guideline shows very well a new policy and deployment direction of maritime policy in China. China is already striving to lead its maintenance stage of domestic legislation into a new stage under the UN maritime laws agreement system and this is an expression of intention to take national policy regarding the ocean as a new milestone for the national economy through concurrent developments in various fields such as national territory, economy, science technology, national defense, and maritime biology. In this point, Chinese maritime policy and maritime legislation provide lots of indexes of lessons in many parts. In particular, regarding Korea, which has to solve many issues with China in Yellow Sea, East China Sea, and Balhae, we have to realize that we can maximize national interest only with a systematic approach to research on changes of domestic policies and maritime legislation within China. In addition, in understanding Chinese maritime related laws, we have to realize it is an important task to not only understand legislative subjects for mutual creation of order within the entire frame of law orders of China but also to predict and react to direction of policy of Chinese domestic legislation through dynamics of these subjects.