• Journal of Magnetics
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• v.17 no.2
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• pp.145-152
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• 2012

Patients who underwent hip arthroplasty using the conventional fat suppression technique (CHESS) and a new technique (IDEAL) were compared quantitatively to assess the effectiveness and usefulness of the IDEAL technique. In 20 patients who underwent hip arthroplasty from March 2009 to December 2010, fat suppression T2 and T1 weighted images were obtained on a 3.0T MR scanner using the CHESS and IDEAL techniques. The level of distortion in the area of interest, the level of the development of susceptibility artifacts, and homogeneous fat suppression were analyzed from the acquired images. Quantitative analysis revealed the IDEAL technique to produce a lower level of image distortion caused by the development of susceptibility artifacts due to metal on the acquired images compared to the CHESS technique. Qualitative analysis of the anterior area revealed the IDEAL technique to generate fewer susceptibility artifacts than the CHESS technique but with homogeneous fat suppression. In the middle area, the IDEAL technique generated fewer susceptibility artifacts than the CHESS technique but with homogeneous fat suppression. In the posterior area, the IDEAL technique generated fewer susceptibility artifacts than the CHESS technique. Fat suppression was not statistically different, and the two techniques achieved homogeneous fat suppression. In conclusion, the IDEAL technique generated fewer susceptibility artifacts caused by metals and less image distortion than the CHESS technique. In addition, homogeneous fat suppression was feasible. In conclusion, the IDEAL technique generates high quality images, and can provide good information for diagnosis.

• Journal of Broadcast Engineering
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• v.21 no.4
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• pp.472-483
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• 2016

This paper proposes a blocking artifacts detection algorithm in frequency domain for MC-FRUC (Motion Compensated Frame Rate Up-Conversion). Conventional MC-FRUC algorithms occur blocking artifacts near interpolated block boundaries since motion compensation is performed from block-based motion vector. For efficiently decreasing blocking artifacts, this paper analyses frequency characteristics of the interpolated frame and reduces blocking artifacts on block boundaries. In experimental results the proposed method shows better subjective quality than some conventional FRUC method and also increases the PSNR(Peak Signal to Noise Ratio) value on average 0.45 dB compared with BDMC(Bi-Directional Motion Compensation).

• The KIPS Transactions:PartD
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• v.18D no.6
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• pp.451-460
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• 2011

The ability to trace change history and dependency relations of software artifacts which are continuously changed has been recognized as an important factor that support quality management activities such as verification, validation, and testing in software system development process. General software configuration management systems provide tracing information for artifacts only within the configuration management system, and it does not go further to changes that occur within personal workspace. This paper provides a solution that helps tracing down not only changes of configuration items but also change history of artifacts existent in personal workspace through the integration of configuration management system and personal workspace. Furthermore, in cases of artifacts which are included in a configuration item, this paper provides a solution that support tracing dependency relations between the artifacts by identifying their version links. For the integration of configuration management system and personal workspace, a revision of configuration item is connected to the artifact's version of the workspace by the tagging mechanism, and traceability for change history and dependency relations of artifacts can be managed more effectively through integrated change process.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.260-269
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• 2018

The purpose of this study is to interpretate the tools and the method of making wooden artifacts by analyzing the trace of tools on the surface of wooden artifacts estimated to be from the 2nd to the 4th century. As a result of analyzing the trace of tools on the surface of 97 items of wood artifacts, it was confirmed that various tools such as rhizome, chisel, claw, hand knife and ax were used to make these artifacts. Particularly, the marks of the turning knife and the turning lathe were confirmed, and it was found that the method of turning operation was used at this time. In addition, it was confirmed that both the Nunjil (tangential process) and the Seonjil (longitudinal process) were used to produce the wooden container artifacts by turning operation. It observes that proper processing method operation was applied to manufacture wooden container artifact depending on its form and intended use.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1144-1149
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• 2020

The magnetic valve of the breast tissue expander generates imaging artifacts during MRI examination, so MRI examination is limited. To evaluate the effect of imaging artifacts on the diagnosis area for patients with breast tissue expander who need MRI examination. Imaging artifacts were measured using self-made phantoms and actual clinical conditions. Imaging artifacts were measured differently depending on the environment of 1.5 Tesla and 3.0 Tesla, and the effects of imaging artifacts were less in the C-spine and L-spine tests. If MRI due to breast cancer metastasis is absolutely necessary, head & neck examination and L-spine can be examined mainly at 1.5 Tesla, but some sequences may cause distortion due to image artifacts. In terms of safety, MRI scans of patients with breast tissue expanders can be performed conditionally at 1.5T, avoiding 3.0T.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.40-47
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• 2006

This paper proposes a multitoning method using threshold modulation of MJBNM(Modified Jointly Blue Noise Mask) for banding artifacts reduction. As banding artifacts in multitoning appear as uniform dot distributions around the intermediate output levels, such multitone output results in discontinuity and visually unpleasing patterns in smooth transition regions. Therefore, to reduce these banding artifacts, the proposed method rearranges the dot distribution by introducing pixels in the neighborhood of output levels that occurs banding artifacts. First of all principal cause of banding artifacts are analyzed using mathematical description. Based on this analytical result, a threshold modulation technique of MJBNM which takes account of chrominance error and correlation between channels is applied. The original threshold range of MJBNM is first scaled linearly sot that the minimum and maximum of the scaled range include two pixel more than adjacent two output levels that cover an input value. In an input value is inside the vicinity of any intermediate output levels produce banding artifacts, the output is set to one of neighboring output levels based on the pointwise comparison result according to threshold modulation parameter that determines the dot density and distribution. In this case, adjacent pixels are introduced at the position where the scaled threshold values are located between two output levels and the minimum and maximum threshold values. Otherwise, a conventional multitoning method is applied. As a result, the proposed method effectively decreased the appearance of banding artifacts around the intermediate output levels. To evaluate the quality of the multitone result, HVS-WRMSE according to gray level for gray ramp image and S-CIELAB color difference for color ramp image are compared with other methods.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.1
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• pp.122-130
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• 2021

The types of artifacts that are observed in intraoperative neurophysiological monitoring (INM) is truly diverse. The removal of artifacts that interfere with the examination is essential. In addition, improving the quality of the examination by removing artifacts is a reflection of the competency of the examiner and is also the best way to ensure patient safety. However, if knowledge of the equipment or anesthesia in the operating room is insufficient due to lack of experience, artifacts cannot be removed even with a method appropriate to the situation. If artifacts are not separated and removed, the reading of the examination results in confusion in the operation process. This can be a fatal problem in neurosurgery that requires rapid and sophisticated procedures. In this paper, the causes of artifacts that occur during surgery are classified into electrical factors, non-electrical factors, and other factors, and a method and examination method for removing artifacts according to the specific situation is mentioned. Although the operating room environment is a very critical place to simultaneously consider various scenarios, we hope that a stable and optimal INM will play a role by knowing the types and causes of various artifacts and how to tackle them.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.4
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• pp.366-372
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• 2002

EEG is the electrical signal, which is occurred during information processing in the brain. These EEG signal are measured by non-invasive method. EEG has many useful information for brain activity, but artifacts which are included in EEG prevents EEG analysis, so many efforts are devoted to remove these artifacts in EEG. However, this study is going to analysis the feature of the EEG mixed with artifacts in forward-looking way, by using this way, we have found the possibility that is actually applicable to system such as control system. We have made feature difference after the linear as well as nonlinear analysis regarding EEG including typical artifacts, eye-blinking, eye rolling, muscle, and so forth.

• The korean journal of orthodontics
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• v.44 no.5
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• pp.229-235
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• 2014

Objective: The aim of this study was to assess artifacts induced by metallic restorations in three-dimensional (3D) dental surface models derived by cone-beam computed tomography (CBCT). Methods: Fifteen specimens, each with four extracted human premolars and molars embedded in a plaster block, were scanned by CBCT before and after the cavitated second premolars were restored with dental amalgam. Five consecutive surface models of each specimen were created according to increasing restoration size: no restoration (control) and small occlusal, large occlusal, disto-occlusal, and mesio-occluso-distal restorations. After registering each restored model with the control model, maximum linear discrepancy, area, and intensity of the artifacts were measured and compared. Results: Artifacts developed mostly on the buccal and lingual surfaces. They occurred not only on the second premolar but also on the first premolar and first molar. The parametric values increased significantly with increasing restoration size. Conclusions: Metallic restorations induce considerable artifacts in 3D dental surface models. Artifact reduction should be taken into consideration for a proper diagnosis and treatment planning when using 3D surface model derived by CBCT in dentofacial deformity patients.

• Journal of Broadcast Engineering
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• v.21 no.6
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• pp.878-888
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• 2016

This paper proposes an efficient method to remove the boundary artifacts of rendered views caused by damaged depth maps in the 3D video system. First, characteristics of boundary artifacts with the compression noise in depth maps are carefully studied. Then, the artifacts suppression method is proposed by the iterative projection onto convex sets (POCS) algorithm with setting the convex set in pixel and frequency domain. The proposed method is applied to both texture and depth maps separately during view rendering. The simulation results show the boundary artifacts are greatly reduced with improving the quality of synthesized views.