• Particle and aerosol research
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• v.9 no.3
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• pp.163-171
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• 2013

Soot particles emitted from combustion processes are often coated by non-absorbing organic materials, which enhance the global warming effect of soot particles. It is of importance to study the condensation characteristics of soot particles experimentally and theoretically to reduce the uncertainty of the climate impact of soot particles. In this study, the condensational growth of soot particles in a tubular coater was modeled by a one-dimensional (1D) plug flow model and a two-dimensional (2D) laminar flow model. The effects of 2D heat and mass transports on the predicted particle growth were investigated. The temperature and coating material vapor concentration distributions in radial direction, which the 1D model could not accounted for, affected substantially the particle growth in the coater. Under the simulated conditions, the differences between the temperatures and vapor concentrations near the wall and at the tube center were large. The neglect of these variations by the 1D model resulted in a large error in modeling the mass transfer and aerosol dynamics occurring in the coater. The 1D model predicted the average temperature and vapor concentration quite accurately but overestimated the average diameter of the growing particles considerably. At the outermost grid, at which condensation begins earliest due to the lowest temperature and saturation vapor concentration, condensing vapor was exhausted rapidly because of the competition between condensations on the wall and on the particle surface, decreasing the growth rate. At the center of the tube, on the other hand, the growth rate was low due to high temperature and saturation vapor concentration. The effects of Brownian diffusion and thermophoresis were not high enough to transport the coating material vapor quickly from the tube center to the wall. The 1D model based on perfect radial mixing could not take into account this phenomenon, resulting in a much higher growth rate than what the 2D model predicted. The result of this study indicates that contrary to a previous report for a thermodenuder, 2D heat and mass transports must be taken into account to model accurately the condensational particle growth in a coater.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.705-707
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• 2017

Stereo-based spatial radiation detection devices can obtain not only spatial distribution information about the radiation source but also distance information from the detection device to the source. And it provides more efficient information on the source than the existing radiation imaging device. In order to provide high-speed information on the spectrum and type of gamma-ray source, a high-sensitivity detection sensor with high sensitivity is required, and a technique capable of solving the saturation phenomenon at a high dose is needed. In this paper, we constructed a high sensitivity sensor for the measurement of multiple gamma - ray spatial distributions using improved function of detection module to solve saturation to high dose and conducted research to increase the scope of a single detector. The result of this paper improves the performance of gamma ray.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.399-413
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• 2004

In this study, a survey was conducted of students of elementary through college on their conceptions of phenomenon related with dissolution, saturation, and extraction. The teaching strategies of elementary and secondary teachers related to dissolution phenomena were also investigated. Most of elementary and secondary school students thought of dissolution as a phenomenon in which particles broke into the spaces between other particles. This explanation called 'space conception' can be sought in elementary school science textbooks. Some of high school students also had this type of thought. A concept of dissolution phenomenon as 'hydration through attraction of solvent and solute' was held by most of students of 11th, 12th grade, and college. This explanation called 'attraction concept' can be sought in high school chemistry textbooks for 11th and 12th grade. But many students of elementary through college used analogies and models related to 'space conception' when they tried to explain the dissolution phenomena. This indicates that the 'attraction concept' was not firmly established in the students' cognition. 90% of elementary school teachers thought and taught dissolution as a phenomenon in which two different size particles were mixing together like as mixing beans and millets. The model does not represent the attractions among solvent-solvent particles, solvent-solute particles, and solute-solute particles. This model only represents the space size effect (smaller size particles fitting into the spaces of larger size particles). Half of the secondary school teachers also had 'space conception' and only 20% of the teachers had 'attraction concept' Many teachers who had 'attraction concept' used to represent explanation related to 'space conception' for teaching dissolution.

• The Korean Journal of Food And Nutrition
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• v.11 no.1
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• pp.6-10
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• 1998

It was determined to effects on cold test(CT) and smoke point (SP) of deodorizing temperature(DT) in corn oil. Increase of DT was induced to decrease of CT in deodorized oil, which was against the winterized oil inleted. Especially, the decrease of CT in deodorized oil was sharply at more than 26$0^{\circ}C$, this phenomenon was supposed to according the increase of total saturation degree as well as SU2, S2U, and S3 type triglyceride content. On the other hand, SP was showed the highest value as 242$^{\circ}C$ at DT as 24$0^{\circ}C$, the value was decreased to 235~238$^{\circ}C$ at DT as 245~27$0^{\circ}C$. This phenomenon was appeared in inverse proportion to the acid value of sample oils. Accordingly, high temperature deodorizing proved to be a very undesirable effect between general physicochemical characteristics, fatty acid composition and CT, SP etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.634-638
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• 2018

Haze is a factor that degrades the performance of various image processing algorithms, such as those for detection, tracking, and recognition using an electro-optical sensor. For robust operation of an electro-optical sensor-based unmanned system used outdoors, an algorithm capable of effectively removing haze is needed. As a haze removal method using a single electro-optical sensor, the dark channel prior using statistical properties of the electro-optical sensor is most widely known. Previous methods used a square filter in the process of obtaining a transmission using the dark channel prior. When a square filter is used, the effect of removing haze becomes smaller as the size of the filter becomes larger. When the size of the filter becomes excessively small, over-saturation occurs, and color information in the image is lost. Since the size of the filter greatly affects the performance of the algorithm, a relatively large filter is generally used, or a small filter is used so that no over-saturation occurs, depending on the image. In this paper, we propose an improved haze removal method using color image segmentation. The parameters of the color image segmentation are automatically set according to the information complexity of the image, and the over-saturation phenomenon does not occur by estimating the amount of transmission based on the parameters.

• Journal of Communications and Networks
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• v.16 no.1
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• pp.10-17
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• 2014

This work investigates two important performance metrics of underlay cooperative cognitive radio (CR) networks: Interference cumulative distribution function of licensed users and outage probability of unlicensed users. These metrics are thoroughly analyzed in realistic operating conditions such as imperfect fading channel information and strict transmit power constraint, which satisfies interference power constraint and maximum transmit power constraint, over Nakagami-m fading channels. Novel closed-form expressions are derived and subsequently validated extensively through comparisons with respective results from computer simulations. The proposed expressions are rather long but straightforward to handle both analytically and numerically since they are expressed in terms of well known built-in functions. In addition, the offered results provide the following technical insights: i) Channel information imperfection degrades considerably the performance of both unlicensed network in terms of OP and licensed network in terms of interference levels; ii) underlay cooperative CR networks experience the outage saturation phenomenon; iii) the probability that the interference power constraint is satisfied is relatively low and depends significantly on the corresponding fading severity conditions as well as the channel estimation quality; iv) there exists a critical performance trade-off between unlicensed and licensed networks.

• Journal of Korean Academy of Nursing
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• v.48 no.1
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• pp.85-95
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• 2018

Purpose: This qualitative study aimed to explore the experience of incivility among nursing students. Methods: Sixteen nursing students who had experienced incivility during their clinical placement were invited for one-on-one interviews until the point of theoretical saturation. The grounded theory approach of Corbin and Strauss was adopted to analyze transcribed interview contents. Results: Incivility occurred in the context of a hierarchical organizational culture, due to nursing students' position as outsiders, non-systematic clinical education, and poor nursing work environment. The experience of incivility was identified as "being mistreated as a marginal person," and nursing students responded to this phenomenon in the following three steps: reality shock, passive action, and submissive acceptance. This process caused students to lose self-esteem and undergo role conflict. Furthermore, nursing students' experience of incivility could eventually lead to workplace bullying in nurses. Conclusion: The results of this study suggest that nursing students' experience of incivility can be a process that threatens their identity. It is necessary to develop educational programs and provide appropriate counseling services so that nursing students can actively cope with the incivility. In addition, institutional plans are needed to ensure safe and supportive clinical learning environments.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.383-394
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• 2007

Due to the clutch's non-linear dynamics, time-delays, external disturbance and parameter uncertainty, the automated clutch is difficult to control precisely during the launch process or automatic mechanical transmission (AMT) vehicles. In this paper, an enhanced fuzzy sliding mode controller (EFSMC) is proposed to control the automated clutch. The sliding and global stability conditions are formulated and analyzed in terms of the Lyapunov full quadratic form. The chattering phenomenon is handled by using a saturation function to replace the pure sign function and fuzzy logic adaptation system in the control law. To meet the real-time requirement of the automated clutch, the region-wise linear technology s adopted to reduce the fuzzy rules of the EFSMC. The simulation results have shown hat the proposed controller can achieve a higher performance with minimum reaching time and smooth control actions. In addition, our data also show that the controller is effective and robust to the parametric variation and external disturbance.

• Research in Community and Public Health Nursing
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• v.12 no.2
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• pp.317-328
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• 2001

The purposes of this study were to develop the empowerment education program, to describe the experiences of diabetes patient's empowerment process and to develop a theoretical model of the diabetes patient's empowerment process. Method 1. : The development of the empowerment program for the diabetes patients: The strategies of the empowerment education program were enhancement of problem - solving, decision making, self-efficacy, self-control. participation and mutual support. Method 2. : According to the grounded theory methodology of Strauss and Corbin, the qualitative data was collected with in depth interviews and participants observations until its saturation when the 25 consented subjects were participating and interacting with the other subjects in the empowerment education program. Results: With the analysis of the data, 29 categories were generated. The core category generated, which was a central phenomenon of the empowerment process, was named powerlessness. The intervening conditions facilitating or impeding the empowerment process were discovered as supportive systems through the participation of group meeting, problem solving dialogue, and the knowledge deficit of self-care. The action/interaction strategies were developed as the paricipating, dialoguing, questioning, supporting system, self-controlling, self efficacy, enhancing self-esteem. stress relaxing and instillation of hope.

• Journal of Korean Academy of Nursing
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• v.46 no.2
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• pp.271-282
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• 2016

Purpose: This study was done to explore adaptation experience of living kidney donors after donation. Specific aims were to identify challenges donors face in the process of adaptation following surgery and how they interact with recipients and other people. Methods: Grounded theory methodology was utilized. Participants were 13 living kidney donors at six months or more after donation. Data were collected by in-depth interviews with individual participants. Data were analyzed using constants comparative method with theoretical saturation. Results: A core category emerged as 'keeping the fences of my family in spite of vulnerability'. The adaptation process after donation was manifested in four phases: exploration, balance, maintenance, and acclimatization. Phenomenon was perception of vulnerability. Strategies to manage the vulnerability were assessing changes of body awareness, tailoring regimen to one's own body condition, coping with health problems, keeping restoration of health, and ruminating on the meaning of one's kidney donation. Consequences were reestablishing family well-being, realizing the values of one's kidney donation, and living with uncertainty. Conclusion: Findings of the study indicate that there is a need for health professionals to understand the vulnerability of living kidney donors and help their family system maintain a healthy and productive life. The results of this study can be used to develop phase-specific, patient-centered, and tailored interventions for living kidney donors.