• Journal of Life Science
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• v.28 no.4
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• pp.472-477
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• 2018

Pravastatin sodium is a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor used in the treatment of hypercholesterolemia by reducing cholesterol biosynthesis. Pharmaceutical excipients of commonly used including water, diluents, stabilizers, disintegrants, lubricants and colorants, and were identified for compatibility. All tests were performed by means of physical mixture of pravastatin and the excipients, which were placed in a press-through-pack (PTP) and incubated under accelerated conditions ($40^{\circ}C$ and 75% relative humidity) for 3 months. The blends of pravastatin with all excipients developed white, off white, and light brown powders, which showed no changes upon visual analysis. Accelerated conditions changed the degradation profile of pravastatin calcium in the HPLC system when mixed with different excipients. Although most excipients can have minor effects on pravastatin stability, the major degradation product from pravastatin was lactone. Low-level interaction (assay and impurity) was induced by all excipients except for microcrystalline cellulose and croscarmellose sodium. These excipients increased lactone impurity in 3 months by as much as 0.22% and 0.18% respectively. The total mixture slightly increased the lactone impurity (by 0.43% in 3 months) of pravastatin. There was no change in the assays of all excipients. These results will be helpful in studying tablet size reductions for convenience of use.

• Progress in Medical Physics
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• v.3 no.1
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• pp.71-78
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• 1992

This study describes the design of the biophysiological signal processing analyzer which can collect and analyze the biosignal raw data. System hardware is consisted of the IBM PC AT. pre-amplifier. AID converter, Counter/Timer. and RS-232C processor. Biophysiological signal data were processed by the software digital filter. FFT and graphic processing routine. The tachogram and FFT of the the peak to peak interval time was accomplished by the Graphic user interface software using the biophysiological signal processed data. Using this system. the powerspectrum of the heart rate variability during the long term could be observed. Experimental results of this system approach our purpose. which is improved the cost performance. easy to use. reducing raw-data noise and optimizing model for digital filter.

• Structural Engineering and Mechanics
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• v.54 no.2
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• pp.257-289
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• 2015

Shear connectors are generally used to link the slab and girders together in slab-on-girder bridge structures. Damage of shear connectors in such structures will result in shear slippage between the slab and girders, which significantly reduces the load-carrying capacity of the bridge. Because shear connectors are buried inside the structure, routine visual inspection is not able to detect conditions of shear connectors. A few methods have been proposed in the literature to detect the condition of shear connectors based on vibration measurements. This paper proposes a different dynamic condition assessment approach to identify the damage of shear connectors in slab-on-girder bridge structures based on power spectral density transmissibility (PSDT). PSDT formulates the relationship between the auto-spectral densities of two responses in the frequency domain. It can be used to identify shear connector conditions with or without reference data of the undamaged structure (or the baseline). Measured impact force and acceleration responses from hammer tests are analyzed to obtain the frequency response functions at sensor locations by experimental modal analysis. PSDT from the slab response to the girder response is derived with the obtained frequency response functions. PSDT vectors in the undamaged and damaged states can be compared to identify the damage of shear connectors. When the baseline is not available, as in most practical cases, PSDT vectors from the measured response at a reference sensor to those of the slab and girder in the damaged state can be used to detect the damage of shear connectors. Numerical and experimental studies on a concrete slab supported by two steel girders are conducted to investigate the accuracy and efficiency of the proposed approach. Identification results demonstrate that damages of shear connectors are identified accurately and efficiently with and without the baseline. The proposed method is also used to evaluate the conditions of shear connectors in a real composite bridge with in-field testing data.

• Smart Structures and Systems
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• v.11 no.6
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• pp.589-604
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• 2013

Identification of damage has become an evolving area of research over the last few decades with increasing the need of online health monitoring of the large structures. The visual damage detection can be impractical, expensive and ineffective in case of large structures, e.g., offshore platforms, offshore pipelines, multi-storied buildings and bridges. Damage in a system causes a change in the dynamic properties of the system. The structural damage is typically a local phenomenon, which tends to be captured by higher frequency signals. Most of vibration-based damage detection methods require modal properties that are obtained from measured signals through the system identification techniques. However, the modal properties such as natural frequencies and mode shapes are not such good sensitive indication of structural damage. Identification of damaged jacket type offshore platform members, based on wavelet packet transform is presented in this paper. The jacket platform is excited by simple wave load. Response of actual jacket needs to be measured. Dynamic signals are measured by finite element analysis result. It is assumed that this is actual response of the platform measured in the field. The dynamic signals first decomposed into wavelet packet components. Then eliminating some of the component signals (eliminate approximation component of wavelet packet decomposition), component energies of remained signal (detail components) are calculated and used for damage assessment. This method is called Detail Signal Energy Rate Index (DSERI). The results show that reduced wavelet packet component energies are good candidate indices which are sensitive to structural damage. These component energies can be used for damage assessment including identifying damage occurrence and are applicable for finding damages' location.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.9-17
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• 2006

Performing inspections for Hull Condition Monitoring and Assessment as stipulated in IACS unified requirements and IMO's Condition Assessment Scheme (CAS) IMO Resolution MEPC.94(46), 2001, Condition Assessment Scheme, IMO Resolution MEPC.111(50), 2003, Amendments to regulation 13G, addition of new regulation 13H involves a huge amount of measurement data to be collected, processed, analysed and maintained. Information to be recorded consists of thickness measurements and visual assessment of coating and cracks. The amount of data and increasing requirements with respect to condition assessment demand efficient computer support. Currently, due to the lack of standardization for this kind of data, the thickness measurements are recorded manually on ship drawings or tables. In this form, handling of the measurements is tedious and error-prone and assessment is difficult. Data reporting and analysis takes a long time, leading to some repairs being performed only at the next docking of the ship or making an additional docking necessary. The recently started ED funded project CAS addresses this topic and develops-as a first step-a data model for Hull Condition Monitoring and Assessment (HCMA) based on XML-technology. The model includes simple geometry representation to facilitate a graphically supported data collection as well as an easy visualisation of the measurement results. In order to ensure compatibility with the current way of working, the content of the data model is strictly confined to the requirements of the measurement process. Appropriate data interfaces to classification software will enable rapid assessment by the classification societies, thus improving the process in terms of time and cost savings. In particular, decision-making can be done while the ship is still in the dock for maintenance.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.57-65
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• 2020

This study is places importance on health and safety in the era of untact, non-face-to-face care areas are increasing. To find out the fun factors and the effect of immersion on use satisfaction of health application users. Through the first factor analysis, we found the fun and immersion elements(joyful, interest, social intercourse) of users. Secondly, we looked at the impact of fun factors and immersion on satisfaction (viral intention, continuity). Finally, we looked at whether the user's characteristics affect satisfaction. The impact on fun factors and satisfaction was different depending on gender, which are characteristics of health application users. Both men and women showed significant results in oral tradition of pleasure, and in the case of women, elements of joy and psychological compensation were found to affect the continuation of use. It is thought that it is important to consider this in terms of marketing so that the elements of enjoyment among the fun factors of users through health application can continuously affect the continuation of use or oral tradition.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.31-41
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• 2009

The Image sensor of digital still camera has a limited dynamic range. In high dynamic range scenes, a picture often turns out to be underexposed or overexposed. Retinex algorithm based on the theory of the human visual perception is known to be effective contrast enhancement technique. However, it happens the unbalanced contrast enhancement which is the global contrast increased, and the local contrast decreased in the high dynamic range scenes. In this paper, to enhance the both global and local contrast, we propose the weight mapping retinex algorithm. Weight map is composed of the edge and exposure data which are extracted in the each retinex image, and merged with the retinex images in the fusion processing. According to the output picture comparing and numerical analysis, the proposed algorithm gives the better output image with the increased global and local contrast.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.799-808
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• 2010

In this study, we conducted a textbook analysis and a conceptual test in order to investigate misconceptions of preservice chemistry teachers in understanding motions of molecular gases. As a result, we found out that many of the general chemistry textbooks not only introduce motions of molecular gases by explaining basic conceptions and using simple models, but also omit the explanation on center of mass when dealing with rotational motion. The physical chemistry textbooks, however, mainly approach motions of molecular gases in terms of spectroscopy and use various models to explain more intensified concepts, referring the center of mass in rotational motions. Meanwhile, pre-service chemistry teachers' confidence and understanding in the motions of molecular gases were very low and pre-service teachers also had many misconceptions about them. We believe this is because they had a tendency to depend largely on their intuition based on the pre-conceptions and the visual materials in the textbooks.

• Journal of the Korean Chemical Society
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• v.61 no.5
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• pp.277-285
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• 2017

The purpose of this study is to investigate the perspective of pre-service chemistry teachers on the learning situations of visually impaired students through scientific inquiry in a darkroom and to propose a teaching and learning method for students with visual impairments. Twenty-one pre-service chemistry teachers from college of education in Gyeongbuk were encouraged to explore individually hands-on model for the molecular structure of ice freely, and had a discussion with a one of the researchers during the activity. All the conversation and discussion were audio-taped and transcribed for analysis. As a result, pre-service chemistry teachers realized that learning situation of the visually impaired students was quite different with their perception while exploring and figuring out hands-on model of the molecular structure of ice in the darkroom. They already learned and could see this model by themselves but also recognized that visually impaired students had inconvenience and difficulty in learning science concepts. Based on these reflections, some pre-service chemistry teachers suggested directions for modification to fit visually impaired students' needs more.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.359-371
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• 2012

The coffee market has been rapidly growing up recently as well as the coffee industry which makes the number of educational institutions increasing in Korea. On the other hand, the classes lean too much on the practical exercise so the coffee education is urgently needed to define precisely and systematize academically. This study is accomplished on the basis of the teachers and students requirement analysis. The features that sets this study apart from the existing educational digital media is that the definite teaching-learning methods and teaching strategies were developed first. Furthermore, the physical and chemical phenomenon of coffee brewing were simulated by 3D animation software based on the visual languages. The general process of this media production was composed by the mutual relationship of the teacher's needs, educationist's strategies and media producer. After applying the digital media to students in the lesson of coffee science theory it was effective to increase their concentrativeness, interesting and learning motive. This media is also receiving the positive evaluation by the teachers to help the students in understanding the coffee science.