• Agribusiness and Information Management
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• v.3 no.2
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• pp.33-42
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• 2011

Although the diffusion of mobile services appears to be occurring much more rapidly than the spread of wired services, there are risks of a new type of digital divide: the mobile divide. The mobile divide, which refers to a specific digital divide that involves the unbalanced diffusion of mobile technologies, must be concretely studied. Thus, this study focuses on the mobile divide with respect to disadvantaged populations. Although various studies suggest that the diffusion of mobile devices may reduce the digital divide, somestudies argue against the positive effect of mobile devices in addressing traditional digital devices. Low and O'Connell (2006) insisted that equity of access to mobile technologies should be considered in the contextof the traditional digital divide; they argued that there may be socio-economic barriers to accessing mobile devices and the mobile Internet that are similar to the socio-economic barriers to accessing stationary computers and the stationary use of the Internet. Focusing on the smartphone divide, this study suggests that emphasizing utilization is an appropriate manner in which to bridge the mobile divide rather than focusing on other factors, such as accessibility and capability, thatprevious studies have used to measure the traditional digital divide.

• Design & Manufacturing
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• v.12 no.1
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• pp.1-6
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• 2018

In this study, we calculated the redistribution of vacancy concentration in metal specimens induced by stress-induced diffusion at a high temperature. To deduce the governing equation, we associated the unit volume change equation of strains with a differential equation of vacancy concentration as a function of stress using the stress-strain relationship. In this governing equation, we considered stress as the only chemical potential parameter to stay in the scope of this study, which provided the vacancy concentration equation as of stress gradient in metals. The equation was then mathematically delineated to derive a analytical solution for a transient, one-dimensional diffusion case. With the help of Korhonen's approximation and the boundary conditions, we successfully deduced a general solution from the governing equation. To visualize the feasibility of our solutions, we applied the solution to two different stress-induced cases - a rod with fixed concentrated stresses at both ends and a rod with varying concentrated stresses at both ends. Although it is necessary to legitimatized the model in the future for improvement, our results showed that the model can be used to interpret the location of structural defects, the formation of vacancy, and furthermore the high temperature behavior of metals.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.428-434
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• 2018

Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.2
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• pp.87-93
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• 2015

Recently, the heat exchangers are requiring higher performance and reliability since they are being used under the operating condition of high temperature and pressure. To satisfy these requirements, we need special materials and bonding technology. This study presents a manufacturing technology for high temperature and high pressure micro channel heat exchanger using Inconel 617. The bonding performance for diffusion bonded heat exchanger was examined and analyzed. The analysis were conducted by measuring thermal and mechanical properties such as thermal diffusivity and tensile strength, and parametric studies about bonding temperature and pressing force were also carried out. The results provided insight for bonding evaluation and the bonding condition of $1200^{\circ}C$, and 50 tons was found to be suitable for this heat exchanger. From the results, we were able to establish the base technology for the manufacturing of Inconel 617 heat exchanger through the application of the diffusion bonding.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.127-130
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• 2008

Recently, a wide variety of research on the knowledge-based industries, which are considered a key area of social science research, has been conducted. In this light, this study examines a case of knowledge diffusion taken from the IT service field. The IT service industry has been considered difficult to diffuse due to its unique technological regimes and sophisticated market demand. In particular, the established public service systems have limited markets and encompass national characteristics, thereby making their international diffusion difficult. However, despite these limitations, the automated customs system ASYCUDA has been distributed successfully and is now operating in about 100 countries, making the case very unusual. Using various industrial innovation models, and an analysis of lead markets, with regard to ASYCUDA, this research examines patterns of technological learning activities by actors, characteristics of the lead markets, and paths of technology transfer. The findings indicate that when active technology providers attempt to streamline and standardize the technology to make it suitable for the characteristics of the initial technology application areas(lead markets), this helps to diffuse the technology to passive recipients and the surrounding nations. The findings also confirm that south-south cooperation in the acquired technologies was of considerable help in sharing knowledge among the passive technology recipients, and that the active technology providers' programmed, well-organized technology assistance was a key driving force behind technology transfer and diffusion between the surrounding nations.

• Communications for Statistical Applications and Methods
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• v.17 no.3
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• pp.367-376
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• 2010

Recently various methods were suggested and reviewed for estimating diffusion processes. Out of suggested estimation method, we mainly concerns on the estimation method using saddlepoint approximation method, and we suggest a term saddlepoint approximation(ASP) method which is the simplest saddlepoint approximation method. We will show that ASP method provides fast estimator as much as Euler approximation method(EAM) in computing, and the estimator also has good statistical properties comparable to the maximum likelihood estimator(MLE). By simulation study we compare the properties of ASP estimator with MLE and EAM, for Ornstein-Uhlenbeck diffusion processes.

• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.20-24
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• 2017

Currently, techniques mainly used in semiconductor impurity diffusion processes include furnace thermal diffusion, ion implantation, and vacuum plasma doping. However, there is a disadvantage that the process equipment and the unit cost are expensive. In this study, boron diffusion process using relatively inexpensive atmospheric plasma was conducted to solve this problem. With controlling parameters of Boron diffusion process, the doping characteristics were analyzed by using secondary ion mass spectrometry. As a result, the influence of each variable in the doping process was analyzed and the feasibility of atmospheric plasma doping was confirmed.

• Journal of radiological science and technology
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• v.44 no.1
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• pp.25-30
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• 2021

The purpose was to reduce the distortion of the image that occurs in the temporal bone area due to the very strong differences in susceptibility. A new SS-TSE technique was applied when examining the diffusion-weighted image of the temporal bone, where the auditory and facial nerves to be imaged were very thin and were adjacent to the cranial base including bone and air. This study was conducted from March 2020 to August of the same year, targeting 32 subjects who underwent the diffusion-weighted imaging of the temporal bone. To compare the distortion, existing SS-EPI technique and the new SS-TSE technique were both applied on the temporal bone area. As a result of the study, applying the new SS-TSE technique appeared to lower the distortion of images by 87.44, 46.13 and 42.35 % on the b-value 0, 800 and the ADC images, respectively. In conclusion, when using the new SS-TSE technique on the temporal bone DWI, distortion can be reduced, and thus images with high diagnostic value can be obtained.

• Journal of Sasang Constitutional Medicine
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• v.35 no.4
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• pp.10-22
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• 2023

Objectives The aim of this study is to explore the mechanism of action and target diseases of Sasang constitutional prescriptions using a multiscale interactome approach. Methods The compound and target information of Sasang constitutional prescriptions were retrieved from various databases such as the TM-MC, STITCH, and TTD. Key targets for Sasang constitutional prescriptions were identified by selecting the top 100 targets based on the number of simple paths within the constructed network. Diffusion profiles for Sasang constitutional prescriptions and diseases were calculated based on a biased random walk algorithm. Potential diseases and key mechanisms of Sasang constitutional prescriptions were identified by analyzing diffusion profiles. Results We identified 144 Sasang constitutional prescriptions and their targets, finding 80 herbs with effective biological targets. A cluster analysis based on selecting up to 100 key targets for each prescription revealed a more cohesive grouping of prescriptions according to Sasang constitution. We then predicted potential diseases for 62 Sasang constitutional prescriptions using diffusion profiles calculated on a multiscale interactome. Finally, our analysis of diffusion profiles revealed key targets and biological functions of prescriptions in obesity and diabetes. Conclusions This study demonstrates the effectiveness of a multiscale interactome approach in elucidating the complex mechanisms and potential therapeutic applications of prescriptions in Sasang constitutional medicine.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.481-490
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• 2012

Evaluation of chloride penetration is very important, because induced chloride ion causes corrosion in embedded steel. Diffusion coefficient obtained from rapid chloride penetration test is currently used, however this method cannot provide a correct prediction of chloride content since it shows only ion migration velocity in electrical field. Apparent diffusion coefficient of chloride ion based on simple Fick's Law can provide a total chloride penetration magnitude to engineers. This study proposes an analysis technique to predict chloride penetration using apparent diffusion coefficient of chloride ion from neural network (NN) algorithm and time-dependent diffusion phenomena. For this work, thirty mix proportions with the related diffusion coefficients are studied. The components of mix proportions such as w/b ratio, unit content of cement, slag, fly ash, silica fume, and fine/coarse aggregate are selected as neurons, then learning for apparent diffusion coefficient is trained. Considering time-dependent diffusion coefficient based on Fick's Law, the technique for chloride penetration analysis is proposed. The applicability of the technique is verified through test results from short, long term submerged test, and field investigations. The proposed technique can be improved through NN learning-training based on the acquisition of various mix proportions and the related diffusion coefficients of chloride ion.