• Title/Summary/Keyword: Knowledge flow

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Experimental and Numerical Research on the Airflow Inside Asymmetric Nasal Cavities (비대칭 비강 내 공기유동에 관한 실험 및 수치해석적 연구)

  • Kim, Sung-Kyun;Park, Joon-Hyung;Leim, Huynh Quang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.8
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    • pp.749-754
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    • 2010
  • Knowledge of the characteristics of airflow in nasal cavities is essential to understand the physiological and pathological aspects of nasal breathing. In our laboratory, a series of experimental investigations on the nasal airflow was conducted; airflow in models of normal and deformed nasal cavities under both constant and periodic flow conditions was studied by PIV. Some of the patients with asymmetric nasal cavities experience pain or discomfort, while other patients with asymmetric nasal cavities do not experience pain. Airflows inside asymmetric nasal cavities with and without obstructions due to a bent nasal septum are investigated both experimentally by PIV and numerically by using the general-purpose FVM code in order to determine the reason for the above-mentioned discrepancy. The comparisons between two cases are tried. Heat and humidity distribution are investigated numerically.

Interregional Network Analysis of National Innovation Activities (국가 기술혁신활동의 지역 간 네트워크에 관한 연구 : 전기소자 기술을 중심으로)

  • Yoo, Sun-Hi
    • Journal of Information Management
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    • v.37 no.2
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    • pp.93-107
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    • 2006
  • There are some questions about the way to monitoring the regional innovative activities in a specific field because of decision-making for raising regional specialized industry. Numerous studies have been conducted in the past using patent statistics to explain and compare the innovative capabilities of districts, regions and countries. The prior method of calculating the regional distribution of patent counts is to assign the patents to districts by assignee's address, which was not proper, in the case of larger firms's headquarters, holdings or subsidiaries, to mislead in geographical terms. So the regional distribution of patent was counted for a specific technology area, electric device field(H01 IPC classification), by inventors' residential addresses. Then the interregional structure was investigated by analysing the relations of co-inventors' regions by individual patent using a network analysis tool.

The detection of cavitation in hydraulic machines by use of ultrasonic signal analysis

  • Gruber, P.;Farhat, M.;Odermatt, P.;Etterlin, M.;Lerch, T.;Frei, M.
    • International Journal of Fluid Machinery and Systems
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    • v.8 no.4
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    • pp.264-273
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    • 2015
  • This presentation describes an experimental approach for the detection of cavitation in hydraulic machines by use of ultrasonic signal analysis. Instead of using the high frequency pulses (typically 1MHz) only for transit time measurement different other signal characteristics are extracted from the individual signals and its correlation function with reference signals in order to gain knowledge of the water conditions. As the pulse repetition rate is high (typically 100Hz), statistical parameters can be extracted of the signals. The idea is to find patterns in the parameters by a classifier that can distinguish between the different water states. This classification scheme has been applied to different cavitation sections: a sphere in a water flow in circular tube at the HSLU in Lucerne, a NACA profile in a cavitation tunnel and two Francis model test turbines all at LMH in Lausanne. From the signal raw data several statistical parameters in the time and frequency domain as well as from the correlation function with reference signals have been determined. As classifiers two methods were used: neural feed forward networks and decision trees. For both classification methods realizations with lowest complexity as possible are of special interest. It is shown that two to three signal characteristics, two from the signal itself and one from the correlation function are in many cases sufficient for the detection capability. The final goal is to combine these results with operating point, vibration, acoustic emission and dynamic pressure information such that a distinction between dangerous and not dangerous cavitation is possible.

Resolving a velocity inversion at the geotechnical scale using the microtremor (passive seismic) survey method

  • Roberts James C.;Asten Michael W.
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.14-18
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    • 2004
  • High levels of ambient noise and safety factors often limit the use of 'active-source' seismic methods for geotechnical investigations in urban environments. As an alternative, shear-wave velocity-depth profiles can be obtained by treating the background microtremor wave field as a stochastic process, rather than adopting the traditional approach of calculating velocity based on ray path geometry from a known source. A recent field test in Melbourne demonstrates the ability of the microtremor method, using only Rayleigh waves, to resolve a velocity inversion resulting from the presence of a hard, 12 m thick basalt flow overlying 25 m of softer alluvial sediments and weathered mudstone. Normally the presence of the weaker underlying sediments would lead to an ambiguous or incorrect interpretation with conventional seismic refraction methods. However, this layer of sediments is resolved by the microtremor method, and its inclusion is required in one-dimensional layered-earth modelling in order to reproduce the Rayleigh-wave coherency spectra computed from observed seismic noise records. Nearby borehole data provided both a guide for interpretation and a confirmation of the usefulness of the passive Rayleigh-wave microtremor method. Sensitivity analyses of resolvable modelling parameters demonstrate that estimates of shear velocities and layer thicknesses are accurate to within approximately $10\%\;to\;20\%$ using the spatial autocorrelation (SPAC) technique. Improved accuracy can be obtained by constraining shear velocities and/or layer thicknesses using independent site knowledge. Although there exists potential for ambiguity due to velocity-thickness equivalence, the microtremor method has significant potential as a site investigation tool in situations where the use of traditional seismic methods is limited.

The Research of the Analysis of Movement from a Fire using RTLS System (RTLS 시스템을 활용한 화재시 행동분석 연구)

  • Lim, Kyung-Bum;Kim, Ha-Young;Rie, Dong-Ho
    • Fire Science and Engineering
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    • v.24 no.4
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    • pp.98-103
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    • 2010
  • The design disaster prevention of first consideration is security for the people in the buildings. However, it is difficult to make a project for considering variable cases, declined visibility of smoke, distance from another person, mentality, knowledge of clearway etc. This study purpose is, analysis variable cases and modularization of pattern movement to practice basic information for evacuation of simulation which is used RTLS (Real Time Location System) system. It is useful to sense the electric waves from the Tag and grasp the real-time position. The pattern movement of evacuation were analyzed prescription eyeglasses which is used RTLS system to consider following 3 actions; analysis of relations that declined visibility effect the decline of movement velocity, analysis rate of flow with the size of door to estimate the optimum size of door in building and analysis the pattern movement that a bottleneck situation with abundant of people passed together to these exit. The confirmed of propriety of the interpretation about the actual people to evacuate is expected applying the numerical formula in various situation.

A Study on The Conflict Management for Apartment Reconstruction Project (공동주택 재건축사업의 갈등관리에 관한 연구)

  • Lee, Ro-Na;Lee, Hak-Ki
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2008.11a
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    • pp.467-470
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    • 2008
  • Apartment Reconstruction project causes lots of conflicts among stakeholders who don't have professional knowledge on a complicated work-flow In case these conflicts occur, the project might not be well by the damage passed to parties, and so the project cost might be increased, the project might be delayed and hazy as well if the conflicts are not resolved quickly. However, the damage would be indirectly and directly brought to the main parties in apartment reconstruction project because the conflicts aren't managed. Thus, an effective conflict assessment should be preceded, and a process and a system for managing the conflicts should be developed to prevent and settle the conflicts. The purpose of this study classifies the conflicts which are occurred on each phase of the project based on principal facts, and presents the process to develop conflict management system through conflict assessment to each stakeholder.

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Numerical Simulation of Wave Breaking Near Ship Bow

  • Lee, Young-Gill;Kim, Nam-Chul;Yu, Jin-Won;Choi, Si-Young
    • Journal of Ship and Ocean Technology
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    • v.12 no.1
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    • pp.16-27
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    • 2008
  • The interaction between advancing ships and the waves generated by them plays important roles in wave resistances and ship motions. Wave breaking phenomena near the ship bow at different speeds are investigated both numerically and experimentally. Numerical simulations of free surface profiles near the fore bodies of ships are performed and visualized to grasp the general trend or the mechanism of wave breaking phenomena from moderate waves rather than concentrating on local chaotic irregularities as ship speeds increase. Navier-Stokes equations are differentiated based on the finite difference method. The Marker and Cell (MAC) Method and Marker-Density Method are employed, and they are compared for the description of free surface conditions associated with the governing equations. Extra effort has been directed toward the realization of extremely complex free surface conditions at wave breaking. For this purpose, the air-water interface is treated with marker density, which is used for two layer flows of fluids with different properties. Adaptation schemes and refinement of the numerical grid system are also used at local complex flows to improve the accuracy of the solutions. In addition to numerical simulations, various model tests are performed in a ship model towing tank. The results are compared with numerical calculations for verification and for realizing better, more efficient research performance. It is expected that the present research results regarding wave breaking and the geometry of the fore body of ship will facilitate better hull form design productivity at the preliminary ship design stage, especially in the case of small and fast ship design. Also, the obtained knowledge on the impact due to the interaction of breaking waves and an advancing hull surface is expected to be applicable to investigation of the ship bow slamming problem as a specific application.

The Effects of 'Solar System and Star' Using Storytelling on Science Concept and Science Learning Motivation (스토리텔링을 활용한 '태양계와 별' 단원 수업이 과학개념 및 과학학습 동기에 미치는 효과)

  • Kim, Yoonkyung;Lee, Yongseob
    • Journal of the Korean Society of Earth Science Education
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    • v.9 no.1
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    • pp.97-105
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    • 2016
  • The purpose of this study was to examine the effects of storytelling skill on science concept and science learning motivation. For this study the 5 grade, 2 class was divided into a research group and a comparative group. The class was pre-tested in order to ensure the same standard. The research group had the science class with storytelling skill, and the comparative group had the class of the teacher centered lectures on 11 classes in 8 weeks. The storytelling skill was focused on set the astronomical target wants to set up a story, through the small group discussion, present subject of the story, set the protagonist of the story for smooth configuration of the story, in order to smooth the flow of the story, make up a story around a hero, to make a clear story, decorated with pictures, shapes, graphs, etc, group story, complete with an astronomical(saints) in storytelling. To prove the effects of this study, science concept was split up according to knowledge, inquiry, attitude. Also, science learning motivation consisted of assignment is worth, learning beliefs about control, self efficacy. The results of this study are as follows. First, using storytelling skill was effective in science concept. Second, using storytelling skill was effective in science learning motivation. Also, after using storytelling skill was good reaction by students. As a result, the elementary science class with storytelling skill had the effects of developing science concept and science learning motivation. It means the science class with storytelling skill has potential possibilities and value to develop science concept and science learning motivation.

Analysis of National R&D Commercialization Policy: An Out-bound Open Innovation Perspective (유출-개방형 기술혁신으로서의 기술사업화 정책 분석)

  • Ahn, Joon Mo
    • Journal of Korea Technology Innovation Society
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    • v.18 no.4
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    • pp.561-589
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    • 2015
  • Up to present science and technology (S&T) policy in Korea has focused on producing academic papers and patents through the increase of investment on research and development (R&D). However, as the role of science and technology on boosting national economy has been emphasized and the current government has established 'creative economy' as a main policy agenda, 'technology commercialization' has been moving onto the center of S&T policy. Technology commercialization policy encourages R&D outcomes of public R&D institutions to be utilized in private firms for their new business development, and this concept is in line with out-bound open innovation, in the sense that it involves the flow of technological knowledge from public R&D institutions to private firms. Based on this understanding, this paper analyses government technology commercialization programs and attempts to suggest policy implications. The results suggest that future technology commercialization policy (1) be specialized in a way of reflecting the characteristics of each government ministry, (2) strongly support technology licensing-out, (3) strengthen the linkage between each programs, and (4) nurture expert groups, such as accelerators who can help and foster technology start-ups.

Image Segmentation of Lung Parenchyma using Improved Deformable Model on Chest Computed Tomography (개선된 가변형 능동모델을 이용한 흉부 컴퓨터단층영상에서 폐 실질의 분할)

  • Kim, Chang-Soo;Choi, Seok-Yoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.10
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    • pp.2163-2170
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    • 2009
  • We present an automated, energy minimized-based method for Lung parenchyma segmenting Chest Computed Tomography(CT) datasets. Deformable model is used for energy minimized segmentation. Quantitative knowledge including expected volume, shape of Chest CT provides more feature constrain to diagnosis or surgery operation planning. Segmentation subdivides an lung image into its consistent regions or objects. Depends on energy-minimizing, the level detail image of subdivision is carried. Segmentation should stop when the objects or region of interest in an application have been detected. The deformable model that has attracted the most attention to date is popularly known as snakes. Snakes or deformable contour models represent a special case of the general multidimensional deformable model theory. This is used extensively in computer vision and image processing applications, particularly to locate object boundaries, in the mean time a new type of external force for deformable models, called gradient vector flow(GVF) was introduced by Xu. Our proposed algorithm of deformable model is new external energy of GVF for exact segmentation. In this paper, Clinical material for experiments shows better results of proposal algorithm in Lung parenchyma segmentation on Chest CT.