• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.43-49
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• 2002

The NOx emission characteristics of double-concentric diffusion flames and normal diffusion flames fueled with CH$_4$ were studied. Experimental and numerical investigations were carried out for double-concentric diffusion flame with varying central air flow rate and normal diffusion flame. The Emission indices of NOx(EINOx) were measured by chemiluminescent method and calculated by numerical model based on detailed chemistry. From the comparison between double-concentric diffusion flames and normal diffusion flames, the results show that EINOx of double-concentric diffusion flames are lower than normal diffusion flame, because of Prompt EINOx was decreased. EINOx of double-concentric diffusion flames increase with central air flow rate increasing.

• Proceedings of the Technology Innovation Conference
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• pp.226-249
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• 1998

Technology diffusion policy can be defined as the role of government in linking knowledge production with usage. It has an importance due to the fact that linking knowledge between the producing agent and using agent does not automatically occur. If knowledge produced by an R&D agent is not used by somebody else, the knowledge may deteriorate to a social loss since knowledge production consumes a considerable degree of social resources. Explicit technology diffusion policies are not found in Korea. There we, however, a number of implicit policies to promote technology diffusion, mainly by promoting cooperation among universities, industries and research institutes. Government R&D programs have provided incentives for cooperative research projects, and many government sponsored institutes have been assigned the role of technology assistance for small and medium sized firms. Nevertheless, diffusion policies remain weak in comparison to other innovation and technology policies. This is reflected in the relatively small scale of government support for technology diffusion programs. In addition, there is no systematic approach between the different ministries for enhancing diffusion across technologies, institutions, sectors and regions. A comprehensive evaluation of government diffusion programs, which is necessary for improving policy and program design, is lacking. Enhancing the diffusion of technology in Korea will require the strengthening of policies at different levels, including; 1) increasing the orientation of science and technology policies towards diffusion; 2) increasing the scale of existing diffusion programs; 3) developing new diffusion programs, in particular sector-specific or manpower training programs; 4) developing policies to encourage a culture of cooperation that can facilitate technology diffusion; and 5) carrying out substantial policy research to develop diffusion policies.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.90-94
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• 1998

Self diffusion coefficients of $^{67}$Co and impurity diffusion coefficients of $^{51}$Mn and $^{65}$Zn in single crystalline CoO have been measured by applying different radioactive isotopes simultaneously. To compare the residual activity method and the tracer sectioning method we analyzed our tracer diffusion experiments by using both methods simultaneously. According to our experimental results, the diffusion coefficients obtained from both methods are identical within experimental error, demonstrating the relibility of our experimental procedures. The diffusion coefficients of all the isotopes obtained during these test experiments for the methodology are similar in magnitude and show similar dependences on oxygen partial pressure. These first observations indicate that impurity diffusion of Mn and Zn occur via a vacancy mechanism as known for self diffusion of cobalt.

• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.83-90
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• 1996

A diffusion process is often the main mechanism of soil gas/vapor movement in the vadose zone. The diffusion coefficients in the porous soil media are different from those in the free air phase by the reduction of available area for diffusion, tortuous diffusion path and variable cross section area along the diffusion path. To take account those effects of the diffusion process in the porous media, usually the terms of effective diffusion coefficient and tortuosity are have been used. However, as there are many differents definitions for the tortuosity, when the term of tortuosity is used, it is necessary to examine it throughly. Moreover, there are many different equations for the effective diffusion coefficient according to the investigators and the differences in the values of effective diffusion coefficients between the equations are not insignificant, the selection of the equation should be done with caution. In this paper, the different definitions of effective diffusion coefficient are examined and discussed. As well as definitions, the lots of availabe models for the diffusion coefficient in terms of porosities are compared. Also, the constrictiviy which explains the effect of cross sectional area change over the diffusion path was discussed.

• Journal of Information Technology Applications and Management
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• v.17 no.2
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• pp.187-205
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• 2010

This study takes a holistic approach to understand the diffusion of IPTV services by combining the adoption-diffusion model and the use-diffusion model of innovation. IPTV service, a leading digital converged application coupling media content with telecommunications, has been recently launched commercially in Korea. We created a structural model of adoption-diffusion, using the perceived easeof-use and usefulness of TAM(Technology Acceptance Model) as mediating variables, and a structural model of use-diffusion, with the rate of use and the variety of use as mediating variables. To empirically analyze these models, non-users of IPTV were surveyed using the adoption-diffusion model to identify factors influencing their intention to subscribe to the service. Meanwhile, users of IPTV were surveyed using the use-diffusion model to determine the factors that influence their satisfaction with the service and their intention to re-use it. Under the adoption-diffusion model, we found that trialability, household innovativeness and perceived risk were the determinants of user satisfaction with IPTV, and perceived ease-of-use, the mediating factors. Under the use-diffusion model, complementarity and communication were shown to be the determinants of users' satisfaction with IPTV, and variety of use, the mediating factor. We also found that consumers' intention to re-use IPTV was strongly influenced by its relative advantage and perceived risk.

• Proceedings of the Korea Database Society Conference
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• pp.165-180
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• 2010

This study takes a holistic approach to understanding the diffusion of IPTV services by combining the adoption-diffusion model and the use-diffusion model of innovation. IPTV service, a leading Digital converged application coupling media content with telecom, has been recently launched commercially in Korea. We created a structural model of adoption-diffusion, using the perceived ease-of-use and usefulness of TAM(Technology Acceptance Model) as mediating variables, and a structural model of use-diffusion, with the rate of use and the variety of use as mediating variables. To empirically analyze these models, non-users of IPTV were surveyed using the adoption-diffusion model to identity factors influencing their intention to subscribe to the service. Meanwhile, users of IPTV were surveyed using the use-diffusion model to determine the factors that influence their satisfaction with the service and their intention to fe-use it. Under the adoption-diffusion model, we found that trialability, household innovativeness and perceived risk were the determinants of user satisfaction with IPTV, and perceived ease-of-use, the mediating factors. Under the use-diffusion model, complementarity and communication were shown to be the determinants of users' satisfaction with IPTV, and variety of use, the mediating factor. We also found that consumers' intention to re-use IPTV was strongly influenced by its relative advantage and perceived risk.

• ETRI Journal
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• v.11 no.4
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• pp.75-83
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• 1989

The diffusion mechanism of Si in GaAs was investigated using different diffusion sources based on the Si-Ga-As ternary phase equilibria. The Si profiles are measured with secondary ion mass spectrometry and differ significantly for sources taken from the different phase fields in the ternary phase diagram. Neutral As vacancy diffusion is proposed for acceptor Si diffusion anneals using a Ga - Si - GaAs source. Donor Si diffusion using As - rich sources and a Si -GaAs tie line source shows concentration dependent diffusion behavior. Concentration dependent diffusion coefficients of donor Si for As - rich source diffusion were found to be related to net ionized donor concentration and showed three regimes of different behavior: saturation regime, intermediate regime,and intrinsic regime. Ga vacancies are proposed to be responsible for donor Si diffusionin GaAs: $Si_Ga^+V_Ga^-$ (donor Si -acceptor Gavacancy) complex for the extrinsic regime and neutral $V_G$a, for the intrinsic regime.The Si - GaAs tie line source resulted in two branch profiles, intermediate between the As - rich and the Ga - rich source diffusion cases.

• Journal of Agricultural Extension & Community Development
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• v.16 no.1
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• pp.201-235
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• 2009

This study analyzed the demographic characteristics, strengths and weaknesses related to information acquisition of local innovation diffusion types. This study use ordered probit model to find strengths and weaknesses of innovation diffusion type in rural area. The individual characteristics of 'formal extension type', 'situational reaction diffusion type', 'agriculturist connection type', and 'systematic approach type', all differentiated according to innovation diffusion type, were analyzed. Following Choi & Choe(2008), immediacy, accessibility, referability, applicability, and satisfaction were the highest in the situational reaction diffusion type, systematic approach type, formal extension type, and farmers connection type, in the order. And there existed organic contexts among individual characteristics. So this study tried to analyze strengths and weaknesses of innovation diffusion type with a focus on immediacy, which emerged as the most important variable in the process of interpreting innovation diffusion. And the strengths and weaknesses of each innovation diffusion type were presented.

• Journal of Information Processing Systems
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• v.16 no.1
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• pp.49-60
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• 2020

To solve the edge ringing or block effect caused by the partial differential diffusion in image enhancement domain, a new image enhancement algorithm based on bidirectional diffusion, which smooths the flat region or isolated noise region and sharpens the edge region in different types of defect images on aviation composites, is presented. Taking the image pixel's neighborhood intensity and spatial characteristics as the attribute descriptor, the presented bidirectional diffusion model adaptively chooses different diffusion criteria in different defect image regions, which are elaborated are as follows. The forward diffusion is adopted to denoise along the pixel's gradient direction and edge direction in the pixel's smoothing area while the backward diffusion is used to sharpen along the pixel's gradient direction and the forward diffusion is used to smooth along the pixel's edge direction in the pixel's edge region. The comparison experiments were implemented in the delamination, inclusion, channel, shrinkage, blowhole and crack defect images, and the comparison results indicate that our algorithm not only preserves the image feature better but also improves the image contrast more obviously.