• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1205-1211
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• 2012

Recently, the evaluating method of the bone mineral density (BMD) in X-ray absorptiometry image has been studied for the early diagnosis of osteoporosis which is known as a metabolic disease. The BMD, in general, is evaluated by calculating pixel intensity in the bone segmented regions. Accurate bone region extraction is extremely crucial for the BMD evaluation. So, a X-Ray image enhancement is needed to get precise bone segmentation. In this paper, we propose an image enhancement method of X-ray image having multiple noise based sparse representation. To evaluate the performance of proposed method, we employ the contrast to noise ratio (CNR) metric and cut-view graphs visualizing image enhancement performance. Experimental results show that the proposed method outperforms the BayesShrink noise reduction methods and the previous noise reduction method in sparse representation with general noise model.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.2
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• pp.29-33
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• 2010

Among several critical topics in semiconductor fabrication technology, particles in addition to bonded surface contaminations are issues of great concerns. This study reports the development of a system which inspects wafer bond integrity by analyzing laser beam transmittance deviations and the variations of the intensity caused by the defect thickness. Since the speckling phenomenon exists inherently as long as the laser is used as an optical source and it degrades the inspection accuracy, speckle contrast is another obstacle to be conquered in this system. Consequently speckle contrast reduction methods were reviewed and among the all remedies have been established in the past 30 years the most adaptable solution for inline inspection system is applied. Simulation and subsequently design of experiments has been utilized to discover the best solution to improve irradiance distribution and detection accuracy. Comparison between simulation and experimental results has been done and it confirms an outstanding detection accuracy achievement. Bonded wafer inspection system has been developed and it is ready to be implemented in FAB in the near future.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.575-584
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• 2021

The aim of this study was to achieve optimal portal phase while reducing contrast medium by applying weight-based dose protocol compared to standard fixed dose protocol to performing of pediatric abdominal CT examination. Discovery 750HD (General Electric Medical Systems, Milwaukee, USA) was used, and a total of 167 children consisting of 85 men and 82 women under the age of 18 were studied. The group in which the 300 mgI/ml(Xenetix, Guerbet, France) contrast medium was fixedly injected at twice body weight and the group injected with physiological saline while gradually decreasing the injection amount by 10% while applying the weight-based protocol were distinguished. Also, the CT number and SNR of abdominal organs were compared and evaluated while changing the scan delay time. Subjective image quality of enhancement and beam-hardening artifacts of around the heart was assessed with five-point criterion. The group adapted weight-based protocol with 20% reduction in contrast medium was most similar in contrast enhancement in the group with fixed injection at twice body weight. Furthermore, the group with a delay time of 20% had the highest contrast enhancement effect, and the difference in CT attenuation coefficient from the group scanned immediately after injection of the contrast media. Therefore, the appropriate delay time after injection of the contrast agent increased the contrast enhancement of the parenchymal organ. In addition, the weight-based injection protocol with normal saline reduced artifacts around the heart, and the effect of contrast enhancement could be maintained. In conclusion, it is possible to reduce dosage of contrast media through the application of weight-based injection protocols and appropriate latency, and to characterize optimal portal phase imaging on pediatric abdominal CT.

• The Journal of Information Systems
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• v.21 no.2
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• pp.73-96
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• 2012

With emergence of smart technologies(e.g., smartphones), Location-Based Services(LBS) are expected to provide more enhanced values utilizing consumers' personal information than other smart services. However, in contrast to existing smartphone applications, LBS could raised severe consumer's privacy concerns because of rapidly changing information sensitive to consumers. In this context, the purpose of this study is to explore relationships among privacy concerns reduction, trust and intention to use LBS by examining the effect of precedence factors(social presence, reputation, mobile literacy, ability of information control) of privacy concern reduction. In addition, the study investigates the role of personal innovation as a moderating effect between privacy concern reduction and intention to use LBS. The results showed that the proposed precedence factors of privacy concerns with a exception of Mobile Literacy had a positive impact on privacy concerns reduction that then positively affected trust and intention to use LBS. In addition, the relationship between trust and intention to use LBS was significantly supported. Finally, personal innovation as a moderating effect significantly influenced the relationship between privacy concern reduction and intention to use LBS. This study is expected to be a reference for a subsequent study about the spread of LBS application of smartphone. Also, the finding of this study is meaningful for helping service direction to firms providing LBS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.909-914
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• 2002

In this thesis, noise reduction of image with impulse noise in circle image removed noise to harness existing median filter for noise reduction from image data of damage by noise when impulse noise is high or noise reduction is low, but it is not made up of noise reduction to harness existing median filter in case of existence of non-impulse noise. Therefore noise reduction of image with non-impulse noise had to remove noise by morphological arithmetic in this thesis's proposition. In contrast to median filtering, result of edge detection is more efficient after remove non-impulse noise by method of thesis's proposition and it compare and demonstrate through this experimentation.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.115-122
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• 2018

We aims to perform comparative analysis on the dose area and image qualities varying on the slice thickness when using Automatic Exposure Controller (AEC) and manual exposure; thus, it wants to suggest a measure to reduce exposure dose by setting the optimal examination condition for each slice thickness. The method was to set the thickness as Thin, Normal, and Heavy adult and evaluate the dose area, spatial resolution, low contrast resolution, Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) according to each slice thickness by using the AEC and the manual exposure controller. The dose area according to each slice thickness all increased both when using the AEC and the manual exposure. However, the manual exposure showed lower dose area product than the AEC. Spatial resolutions and low contrast resolutions were all observed to be higher than the evaluation standard. Also, the SNR and CNR of each thickness all increased when using the AEC. When using the manual exposure, SNR and CNR increased in all cases other than the Heavy Adult. Consequently, the Thin and Normal Adult showed dose reduction about 2 times when using the manual exposure controller, while ensuring the image quality. Heavy adult was able to maintain good image quality by using AEC.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.15-24
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• 2013

Purpose: With the demand of SPECT/CT increasing, the interest in complex diagnostic information of CT is rising along with the expansion of various studies on potential performance value. But the study on reduction of exposure dose generated by CT is not being conducted enough. Therefore, in this study, the goal is to identify how much dose reduction exists when performing the extremity bone SPECT/CT using the flat-panel CT. Materials and Methods: The extremity bone SPECT/CT was performed with two equipments -BrightView XCT (Philips Healthcare, Cleveland, USA) and Brilliance 16 CT (Philips Healthcare, Cleveland, USA)-to identify the exposed dose and image quality resulted by changing scan parameter (mAs) applying for both equipment respectively. The noise value of image and spatial resolution were measured with AAPM CT phantom. Tube voltage (kVp) was fixed to 120 kVp, tube current (mAs) calculated at different mA (20, 30, 40, 50, 60, 70, 80) was applied to both equipments respectively. DLP (dose length product) were calculated at the same distance at respective mAs. Also, we acquired images and % contrast with NEMA IEC body phantom to confirm the effect on image. The output of statistics was analyzed by SPSS ver.18. Results: Regarding AAPM phantom, the noise decreased as the tube current (mAs) increased and flat-panel had less noise than Helical CT. This difference increased at lower dose exposure. As to the evaluation of spatial resolution, we can differentiate the space up to 0.75 mm with both equipments. With scan parameter (mA) growing, the value of DLP increased up to 54-216 mGy cm at flat-panel CT and up to 177-709 mGy cm at Helical CT. Regarding NEMA IEC body phantom, same sphere with varied parameter (mA) shows that similar results. Conclusion: There is no significant differences of image quality in both flat-panel and Helical CT when the scan parameter (mA) is changed respectively. Moreover, we can identify the reduction of exposure dose and confirm %contrast analysis value with maintaining image quality. Therefore, at the extremity bone SPECT/CT requiring high spital resolution without the wide ROI, the flat-panel CT is considered to be more useful and it expected to result in the similar image quality with lower exposure dose compared to Helical CT. Additionally, through this study, we expect to help the reduction of the unnecessary exposure dose.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.355-361
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• 2001

A Chromate tolerant strain of Pseudomonas aeruginosa isolated from the effluent of a tannery showed significant enzymatic activity of chromate reduction. Cells grown in chromate-supplemented medium reduced 8 $\mu\textrm{g}$ chromate/mg protein/h in the presence of NADH/NADPH. The chromate reducing activity was inducible as cells pregrown in chromate showed higher chromate reduction. In contrast, the periplasmic fraction of cells gown in chromate reduce $75\%$ chromate in 4 h and the spheroplast fraction failed to do so, indicating that chromate reductase may be located in the periplasm. The presence of a 30 kDa protein in the periplasmic extracts of cells grown in the presence of chromate, but its absence of the protein in cells grown without chromate, points out a possible role of this protein in chromate reduction.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.307-317
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• 2003

In this study, the material cycle model was applied to suggest alternative management of water quality for Jeju Harbor. The distribution of COD, DIN (dissolved inorganic nitrogen) and DIP (dissolved inorganic phosphorus) concentrations was reasonably reproduced by simulations on the model area of the Jeju Harbor using a material cycle model. The simulations of COD, DIN and DIP concentrations were performed under the conditions of 20∼100% pollution loadings reductions from pollution sources. In case of the 100% reduction of the input loads from Sanzi river, concentrations of COD, DM and DIP were reduced to 39%, 78% and 52%, respectively at Jeju harbor. In contrast, in case of the pollutant loadings reductions from sediment, the effect of DIN and DIP reduction relatively seemed to increase around the center of study area. The 95% reduction of the pollutant loadings from river and sediment is required to meet the COD and nutrients concentration of second grade of ocean water quality criteria.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.35-45
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• 2015

Total industrial accident rate in Korea is facing a record 0.7% for 10 years since 2000. After entering the continuous versus 0.6% (0.69%) in 2010. In 2011, the decrease was reduced to 0.65%. Conversely In contrast to foreign workers' share has increased dramatically over 10 years since 2000 to 2010 are expected to be difficult in the accident rate of 0.5% for the entry. Despite the ongoing disaster reduction efforts to reduce disaster (share) of foreign workers has been increasing rapidly Survey, Whilst the provision of disaster prevention system status and problem analysis and identify measures that can be established through such disaster reduction measures are urgently needed.