• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.470-483
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• 1990

Turbulent jet in a crossflow, issuing from a row of holes on a convex surface of 90 .deg. bend duct, is predicted by a 3-dimensional numerical method. The Cartesian coordinate system in adopted in upstream and downstream tangents and the cylindrical polar coordinate system in curved region. The Reynolds stresses and heat fluxes are obtained from a standard k-e model in the core region and van Driest model in the vicinity of the wall. The governing equations are discretized by a finite volume method and solutions are obtained by a locally elliptic calculation procedure. Pressure and convective terms are treated by SIMPLE algorithm and hybrid scheme respectively. A vortex initially induced by the injected jet has been built up due to the interaction with the secondary flow caused by pressure gradient and centrifugal force. The vortex structure has a strong influence on the wall cooling effectiveness. Another vortex like horseshoe is formed in the vicinity of the injection hole and its strength is getting weak as it moves downward.

• Journal of Information Science Theory and Practice
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• v.1 no.3
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• pp.12-32
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• 2013

The paper introduces the research area of interactive information retrieval (IIR) from a historical point of view. Further, the focus here is on evaluation, because much research in IR deals with IR evaluation methodology due to the core research interest in IR performance, system interaction and satisfaction with retrieved information. In order to position IIR evaluation, the Cranfield model and the series of tests that led to the Cranfield model are outlined. Three iconic user-oriented studies and projects that all have contributed to how IIR is perceived and understood today are presented: The MEDLARS test, the Book House fiction retrieval system, and the OKAPI project. On this basis the call for alternative IIR evaluation approaches motivated by the three revolutions (the cognitive, the relevance, and the interactive revolutions) put forward by Robertson & Hancock-Beaulieu (1992) is presented. As a response to this call the 'IIR evaluation model' by Borlund (e.g., 2003a) is introduced. The objective of the IIR evaluation model is to facilitate IIR evaluation as close as possible to actual information searching and IR processes, though still in a relatively controlled evaluation environment, in which the test instrument of a simulated work task situation plays a central part.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.43-49
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• 2018

Southeast Asia is a strategic market for both technology and inspection system to enter simultaneously. At the core market is Vietnam which is know to have the fourth highest registration of motorcycles as of 2016. The Motorcycle Inspection System is a social regulation, furthermore, the impact of the system is delivered through indirect means such as minimization of social cost. Therefore, measurements on the perception of users on the needs for an inspection system serves as valuable data to simultaneously enter this markets. This research is an empirical study on the perception of Vietnamese users on the needs to adopt a motorcycle inspection system based on data collected through surveys and is aimed at conducting a preliminary investigation on consumer behavior in Vietnam. The empirical study conducted through surveys revealed that Vietnamese motorcycle users perceive the needs for an inspection system for maintenance, safe operations and selling used vehicles at a reasonable price. In addition, the study also verified that the safe operations factor has a moderating effect due to interaction between prevention of illegal vehicle and reduction of emission gases. This research results present implications in developing equipment adapted to the local area in order to enter into a strategic market. Moreover, it is expected that the findings will also serve as valuable data for bilateral cooperation between the two countries and the diffusion of technology.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.9-17
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• 2013

In this study, an efficient analytical model for the dynamic analysis of tall buildings with a shear wall-frame structural system has been proposed. A shear wall-frame structural system usually consists of a core wall showing flexural behavior and a frame presenting shear behavior. Therefore, the deformed shape of the shear wall-frame structural system is shown by the combination of flexural mode and shear mode. These characteristics should be considered when an efficient analytical model is developed. To this end, the effect of shear wall and frame on the dynamic behavior of a tall building with a dual system has been separately investigated. In this study, the structural characteristics of a separated individual shear wall model and the frame model without shear wall has been evaluated. In order to consider the effect of the shear wall in the frame model without shear wall, a rigid body was used instead of the shear wall. Each equivalent model for the separated shear wall part and frame part has been independently developed and two equivalent models were then combined to create an efficient analytical model for tall buildings with a shear wall-frame structural system. In order to verify the efficiency and accuracy of the proposed method, time history analyses of tall buildings with a shear wall-frame system were performed. Based on analytical results, it has been confirmed that the proposed method can provide accurate results, requiring significantly reduced computational time and memory.

• Polymer(Korea)
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• v.28 no.2
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• pp.154-161
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• 2004

Modified poly(4-vinylpyridine) was obtained by partial quarternization of nitrogen atoms in pyridine rings of poly(4-vinylpyridine) with methyl group. By means of laser light scattering and fluorescence, it was found that this modified polymer chains were aggregated in the aqueous solution and its structure was core-shell type. The hydrophobic parts of the chains were densely condensed in core part and the hydrophilic part of quarternized amino with positive charge formed the shell part. In the mixed system of modified poly(4-vinylpyridine) and anionic surfactant, sodium dodecyl sulfate, it was observed that a critical aggregation concentration existed and that this critical concentration was suddenly decreased above 0.1 M NaCl. The size change of aggregates was also investigated by dynamic light scattering while sodium dodecyl sulfate was added into polymer solution upto the critical aggregation concentration.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.519-526
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• 2012

Human-human interaction network derived from Roman-fleuve, Togi was constructed. The network has a scale free properties as if most social networks do. The Togi is excellent model system for analyzing network dynamics because it has various characters and complex their interactions. The novel is composed of well-separated 5 sections. I constructed 5 different sub-netwotks from each section. As employing k-core algorithm as a useful tool for obtaining a core network from the complex networks, it is possible to obtain hidden and valuable information from a complex network. As gradually extending one section to another one, I constructed 4 different extended networks. The final one is whole network from the Togi. These results provide new insight that is analyzed by network-based approaches for network dynamics from literature, Togi.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.121-127
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• 2008

User needs in residential environment have very complicated and variety connection with others. u-home system for the near future is need to be combined acceptance of exist user needs as well as needs on new technology relating with u-Home. The study proposes a User Behavior Analysis Framework - UBAF for applying the user needs to the system more efficiently and developing the system by classifying patterns for the needs based on date of user behavior analysis. UBAF is a developing framework getting the basic idea of combining system modeling methods on SE and user modeling methods considering on HCI. It will be applicable to develop the system with core user behaviors by applying a standard way on u-Home. For example, the study transforms information into knowledge the system modeling and user modeling with analyzing a scenario for indoor temperature controlling on u-Home.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.488-492
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• 2010

In order to verify the performance of high-speed train and core equipments such as current collection system, sophisticated tests and evaluating procedures must be considered. In case of force sensor to test contact force of pantograph, it should customize the test instruments according to characteristics of pantograph. In this paper, the force sensor with a built-in strain-gauge which developed to improve measuring performance of contact force between the pantograph and catenary system is introduced. The test and evaluation results of force sensor's static and dynamic calibration with pantograph shows that its design is very suitable and applicable for on-line test. Henceforth, the force sensor will be applied to test interaction characteristics between the pantograph and catenary system on the high-speed line and expected by a part of measuring system for evaluating current collecting characteristics more reliably.

• Advances in aircraft and spacecraft science
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• v.1 no.3
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• pp.331-351
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• 2014

The paper presents the development of numerical models referred to a morphing actuated aileron. The structural solution adopted consists of an internal part made of a composite chiral honeycomb that bears a flexible skin with an adequate combination of flexural stiffness and in-plane compliance. The identification of such structural frame makes possible an investigation of different actuation concepts based on diffused and discrete actuators installed in the skin or in the skin-core connection. An efficient approach is presented for the development of aeroelastic condensed models of the aileron, which are used in sensitivity studies and optimization processes. The aerodynamic performances and the energy required to actuate the morphing surface are evaluated and the definition of a general energetic performance index makes also possible a comparison with a rigid aileron. The results show that the morphing system can exploit the fluid-structure interaction in order to reduce the actuation energy and to attain considerable variations in the lift coefficient of the airfoil.

• Research in Community and Public Health Nursing
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• v.21 no.4
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• pp.468-480
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• 2010

Purpose: This study was to describe and develop public health nursing. Methods: Data were collected from 19 nurses sampled from 5 public health centers. The grounded theory of Strauss and Corbin (1990) was applied. Results: As a result, 48 concepts, 23 subcategories, and 11 categories were deduced from open coding. In axial coding, casual conditions 'facing difficulties of practical administration' and 'attaching importance to health support for residents' and context condition 'assessing of residents' service needs' impacted phenomenon 'searching for efficient performing methods.' Intervening conditions 'forming of support system' and 'working with positive,' and action-interaction conditions 'improving of resident's health and medical accessibility' and 'striving for self-development' lead to consequences 'carried out promptly for field-based problem solving,' 'mastered of successful program planning methods' and 'solving the issues with existing style.' The periods of process were divided into 4 stages, confirming program-contents, probing program-method, developing program-strategies, and applying program-competencies. The core category, ‘strengthening of practical-planning work competencies' incorporated the relationship between and among all categories and explained the process. Conclusion: This study described public health nurses' performance in Korea. These findings have important implications for the practice and must be considered to develop competencies for planning and practice of public health.