• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.359-365
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• 2024

Chemiresistive semiconductor metal oxide (SMO) gas sensors detect gases based on resistance changes caused by gas adsorption/desorption on SMOs. These sensors have witnessed significant advancements with the development of microelectromechanical systems (MEMS) and nanotechnology. MEMS technology has facilitated mass production, miniaturization, and uniformity across sensors. Whereas, nanotechnology has contributed to the development of high-sensitivity gas sensing materials with large surface areas, catalytic coatings, and hybrid SMO junctions. However, SMOs require activation via external energy to overcome their bandgap energy and generate hot electron carriers, which are essential for high sensitivity and fast response/recovery times. Traditionally, embedded heaters have been used for this purpose; however, micro-and nano-heaters are plagued by high power consumption and low durability, which limit their use in mobile applications. Consequently, photoactivated gas sensing using light sources (e.g., lamps and LEDs) has garnered attention as an alternative approach. This study reviewed the progress from early lamp and LED-based research to recent studies on monolithic micro-LED (µLED) based gas sensors. µLED gas sensors facilitate room-temperature operation and ultra-low power consumption within the microwatt range. Consequently, they are highly suitable for integration into consumer electronics, smart farms, smart factories, and mobile gas sensors.

• Nuclear Engineering and Technology
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• v.3 no.3
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• pp.148-154
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• 1971

Some formulae have been derived for the handy calculation of the formation of radioisotope when a reactor is operated regularly on a usual on-off pattern. In particular, the case of isotope production with the present operation condition of tile Korean reactor, which is in operation for 8.2 hours from Monday to Thursday and is not operated on friday and Sunday but is back in operation on Saturday only for 3.2 hours, is discussed herein with special emphasis. Should there be no secondary nuclear reaction resulting in the transformation of produced nuclide, the formula for the calculation of its activity could be derived as follows: (equation omitted) where A: activity (dps), $\Phi$： neutron flux (n cm$^{-2}$ sec$^{-1}$ ), No : number of atoms before the irradiation, $\sigma$ : activation cross section ($\textrm{cm}^2$), λ : disintegration constant of the radioactiveisotope formed (hr$^{-1}$ ), t : elapsed time of target in the reactor (hr), n : number of elasped days of target in the reactor, m : number of days from the first day of sample irradiation to Friday, s, r, q: number of weekday of Friday, Saturday and Sunday, respectively. Since the above formula consists of many invariables on the whole, the activity of each radioisotope to be produced can he easily and conveniently made available from the chart in advance which is made of the invariable terms calculated.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.1
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• pp.9-17
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• 2009

Twenty years have passed since the adoption of natural recreation forests and each forest has its own characteristics. However, there is hardly any classification among the natural recreation forests. The purpose of this study is to classify the forests by considering the supplier's perspective as well as the user's perspective in order to provide fundamental materials for the operation of the natural recreation forests. A factor analysis was conducted to identify the common characteristics of the selected twelve variables by pre-selection and survey of experts. K-means cluster analysis was conducted among those factors to classify the natural recreation forests in Korea. Four factors were drawn after the factor analysis and the factors were named according to the variables and sizes as 'The use performance and visiting condition factor', 'Education and settlement factor', 'Internal activation factor' and 'Potential factor' In addition, the cluster analysis of an $85{\times}4$ matrix was conducted for the points of the drawn factors and the final classification consists of five groups. The results of this study may contribute to providing fundamental materials for the operation and management of natural recreation forests. Also, it may act as a reference when investigating the natural recreation forests of Korea. Proposing the classification natural recreation forests could be helpful in selecting the proper recreation forest in the future. Based on the established model, fundamental materials could be provided to improve the profitability of the natural recreation forests by effectively expanding the number of tourists, creating new natural recreation forests and proper maintenance and management.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.106-112
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• 2011

Purpose: Until now, the process was improved by the needs of experimenters personally. But recently, suggestion system in hospital has been activated in various ways. So the department of nuclear medicine laboratory is also aware of the need of operation improvement using suggestion system. It is intend to assist in the development by sharing excellent suggestion cases with other hospitals. Material & Method: A total of 124 suggestion cases from January 2007 to March 2010 were analyzed. Suggestion cases were divided into customer satisfaction, cost reduction, improved testing methods, equipment, environmental improvement, and computational system. Result: Suggestion cases of environmental improvement and computational system were accounted for 26.6% as 33 cases, respectively. Suggestion for customer satisfaction is 25.8% as 32 in a total of 124 cases. Conclusion: Activation of the awareness of operation improvement is induced by suggestion system. By securing system of operation improvement, employees' ideas can lead to the production and systematization. Furthermore, it enhances hospital competitiveness and promotes the development of the hospital.

• Journal of Practical Engineering Education
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• v.15 no.2
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• pp.381-388
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• 2023

Through artificial neural network education using spreadsheets, non-major undergraduate students can understand the operation principle of artificial neural networks and develop their own artificial neural network software. Here, training of the operation principle of artificial neural networks starts with the generation of training data and the assignment of correct answer labels. Then, the output value calculated from the firing and activation function of the artificial neuron, the parameters of the input layer, hidden layer, and output layer is learned. Finally, learning the process of calculating the error between the correct label of each initially defined training data and the output value calculated by the artificial neural network, and learning the process of calculating the parameters of the input layer, hidden layer, and output layer that minimize the total sum of squared errors. Training on the operation principles of artificial neural networks using a spreadsheet was conducted for undergraduate non-major students. And image training data and basic artificial neural network development results were collected. In this paper, we analyzed the results of collecting two types of training data and the corresponding artificial neural network SW with small 12-pixel images, and presented methods and execution results of using the collected training data for Orange machine learning model learning and analysis tools.

• Journal of Chest Surgery
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• v.31 no.10
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• pp.952-963
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• 1998

Background: Cardiopulmonary bypass(CPB)-induced hemostatic defects may result increased possibility of excessive hemorrhage and additional multiple transfusion reactions or reoperation. Particularly, fibrinolytic activation and decreased platelet count and function by CPB were proposed as a predictor of hemorrhage during postoperative periods in several reports. Materials and methods: Present study, which was conducted in 20 adult patients undergoing CPB, was prospectively designed to examine the hematologic changes, including fibrinolytic activation during and after CPB and to clarify the relationships between these changes and the magnitude of the postoperative nonsurgical blood loss. The serial blood samples for measurment of hematologic parameters were taken during operation and postoperative periods. Blood loss was respectively counted via thoracic catheter drainage at postoperative 3, 6, 12, 24, 48 hours and total period. Results: The results were obtained as follows:Platelet count rapidly declined following CPB(p<0.01), which its decreasing rate was an inverse proportion to total bypass time(TBT, r=0.55, p=0.01), And platelet count in postoperative 7th day was barely near to its control value. Fibrinogen degradating product(FDP) and D-dimer level significantly increased during CPB(p<0.0001, p<0.0001, respectively), and both of fibrinogen and plasminogen concentration correlatively decreased during CPB(r=0.57, p<0.01), implying activation of fibrinolytic system. Postoperative bleeding time (BT), postoperative activated partial thromboplastin time(aPTT) and postoperative prothrombin time (PT) were significantly prolonged as compare with each control value (p=0.05, p<0.0001, p<0.0001, respectively). Total blood loss was positively correlated with patient's age, aortic clamping time (ACT) and TBT, while there was negative correlation between platelet count and blood loss at pre-CPB, CPB-off and the 1st postoperative day, and in some periods. Postoperative aPTT and postoperative PTwere positively related to postoperative 6 hr and 48 hr blood loss(r=0.53, p=0.02; r=0.43, p=0.05) but not to total blood loss, whereas there was no relationship between postoperative BT and blood loss at any period. Conclusions: These observations suggest that CPB results various hematologic changes, including fibrinolytic activation and severe reduction in platelet count. Diverse factors such as age, platelet count, ACT, TBT and postoperative aPTT and PT may magnify the postoperative bleeding. This study will be a basic reference in understanding CPB-induced hemostatic injuries and in decreasing the postoperative hemorrhage

• Journal of the Korean earth science society
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• v.35 no.3
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• pp.203-212
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• 2014

It is important to explore ways that reinforce teachers' curricular expertise at the school level as the school curriculum autonomy expands. This study investigated teachers' curricular expertise that is required for teachers' professionalism, autonomy, and accountability to cope with the increasing school curriculum autonomy. Teachers in the future school are expected to explore and develop school level curriculum within a given school context. Through literature reviews, domestic and foreign case studies, and survey of teachers, this study examined difficulties in science teachers' exercise of their professionalism on curriculum organization and implementation at the school level. Difficulties in exercising teachers' curricular expertise include lack of actual autonomy in curriculum operation at the school level, inadequate infrastructures, demanding accountability based on students' achievement results, lack of time for reflection, and lack of recognition for teachers as independent curriculum designers. In the conclusion section, a couple of ways to solve these difficulties are suggested including expansion of actual autonomy, activation of teachers' participation in policy decision making, reinforcement of qualitative components in school assessment, diversification of the teacher's career ladder, and activation of teachers' participation in professional learning communities.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.540-552
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• 2020

The purpose of this study is to analyze forest healing from a Buddhist perspective and improve its effect, and the forest has a close relationship with Buddhism than any religion. the Buddha's life is connected to forest and tree, which is caused by the spiritual nature and role of forest. Healing deals with the problem of suffering of the mind, and in Buddhism, it is solved through practice. By understanding the phenomenon of delusions such as thoughts, greed, and bad feelings about sensory control, vhfptmxmhelps to escape from the desire to pursue unnecessary stimuli or external objects, Human beings can get comfort and pleasure through the five senses in the beautiful natural scenery, and find the stability of the mind. This is because when entering the forest, good environments that prevent the 6th consciousness from growing delusions way the operation of the five senses are contained in the forest, This study is a preliminary study that analyzed the effects based on the natural environmental healing factor and Buddhist theory of forests based on previous studies, As a result of examining whether Buddhism can maximize the healing effect of forest healing, it was confirmed that it can contribute to activation along with existing forest healing techniques, The verification of the effectiveness will be left as a follow-up research project through future experimental research, and this study is expected to contribute to the activation of forest healing effect.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.713-721
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• 2012

In many instances phosphorus is a limiting factor for eutrophication in streams, and lakes. Because wastewater treatment plant itself may be the main phosphorus source in a natural water body, removal of phosphorus in final effluent of wastewater treatment processes is required. Amongst various technologies for phosphorus removal in wastewater, adsorption technology was investigated using activated Ca-loess complex. Ca was added in loess to enhance adsorption capacity and intensity of phosphorus. Ca added loess was activated at a high temperature of $400^{\circ}C$ which turned out to be the optimum temperature. Activated Ca-loess complex below $400^{\circ}C$ had not enough strength to be applied as an activated Ca-loess pallet column in wastewater treatment process. Ca-loess complex which activated above $400^{\circ}C$ lost its adsorption capacity as the loess surface was glassified when the activation temperature reached above $400^{\circ}C$20. Even if adsorption capacity of activated Ca-loess was not very high due to the lack of abundant pores on its surface, adsorption intensity was still high because it was activated with added Ca in loess. Activated loess was made by pallets. The activated loess pallets were filled in a column, and were applied in wastewater treatment process. Using an activated Ca-loess pallet column, total phosphorus (T-P) was reduced from about 0.5 mg/l to lower than 0.1 mg/l in wastewater treatment, and ionic phosphorus (phosphate) was completely removed for the four months of pilot plant operation.

• Journal of Distribution Research
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• v.16 no.5
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• pp.43-61
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• 2011

In this research, we analyze about the effect of the traditional market supporting policy about 16 large unit self-governing bodies and effeciency through DEA analysis. The plan for supports of the traditional market were shown. Now, the object of the traditional market supporting policy was any more not improvement of facilities and the thing which is the attraction of customer activity for the sales increase of the traditional market could be confirmed. For the sales increase, supporting of the field like the client information center, source indicator, autonomic packing stand, and the broadcasting facility are effective more. In addition, for the visiting customer inducement activation, we could know that supporting of the field like client information center, broadcasting facility, broadcasting advertisement, and the premium event for gift certificate were required. The method including the customer distribution service operation, which is the various product development and cross sellings and client friendly based on data which it investigates the actual conditions the market merchant on the Incheon area and consumer with the concrete plan for support gift certificate activation, the market information system construction, and etc. was shown.