• Imaging Science in Dentistry
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• v.38 no.2
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• pp.73-79
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• 2008

Purpose: To assess the internal echo intensity and morphological variability of masseter muscles on ultrasonography and to establish diagnostic criterion of estimation. Materials and Methods: Participants consisted of 50 young adults (male 25, female 25) without pathologic conditions and with full natural dentitions. Sonographic examinations were done with real time ultrasound equipment as Logiq 500 (GE Medical Systems, Seoul, Korea) at 3 parts according to lines paralleling with ala-tragus line as reference line. The thickness and area of masseter muscles according to reference line in cross-sectional images were measured at rest and at maximum contraction. The visibility and width of the internal echogenic intensity of the masseter muscles were also assessed and the muscle appearance was classified into 4 types. Data were statistically analyzed by paired t-test and $x^2$-test. Results: 1. When comparing the thickness and area of masseter muscles concerning with gender, there was few significant difference between right and left sides, however, there were significant differences between males and females except for the greatest thickness of left side. 2. The changes of the greatest thickness and the area between rest and maximum contraction showed that the part of the least thickness manifested more increase at maximum contraction. 3. Each part the manifestations of the internal echogenic intensity of the masseter muscles were different depending on the locations. But there was no statistically significance. Conclusion: Changes of muscles thickness with contraction and internal echogenic intensity with locations showed great disparity within the masseter muscles, which will be diagnostic criteria for pathophysiologic and anatomic changes of masseter muscles.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.127-135
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• 2009

Most traffic information that drivers receive while driving are stored in their short-term memory and disappear within a few seconds. Contemporary modeling approaches using a dummy variable can't fully explain this phenomenon. As such, this study proposes to use utility functions of real-time in-vehicle traffic safety information (IVTSI), analyzing its safety impacts based on empirical data from an on-site driving experiment at signalized intersection approach with a limited visibility. For this, a driving stability evaluation model is developed based on driver's driving speed choice, applying an ordered probit model. To estimate the specified utility functions, the model simultaneously accounts for various factors, such as traffic operation, geometry, road environment, and driver's characteristics. The results show three significant facts. First, a normal density function (exponential function) is appropriate to explain the utility of IVTSI proposed under study over time. Second, the IVTSI remains in driver's short-term memory for up to nearly 22 second after provision, decreasing over time. Three, IVTSI provision appears more important than the geometry factor but less than the traffic operation factor.

• Journal of Chest Surgery
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• v.50 no.1
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• pp.36-40
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• 2017

Background: Surgical treatment of thoracic outlet syndrome (TOS) is necessary when non-surgical treatments fail. Complications of surgical procedures vary from short-term post-surgical pain to permanent disability. The outcome of TOS surgery is affected by the visibility during the operation. In this study, we have compared the complications arising during the supraclavicular and the transaxillary approaches to determine the appropriate approach for TOS surgery. Methods: In this study, 448 patients with symptoms of TOS were assessed. The male-to-female ratio was approximately 1:4, and the mean age was 34.5 years. Overall, 102 operations were performed, including unilateral, bilateral, and reoperations, and the patients were retrospectively evaluated. Of the 102 patients, 63 underwent the supraclavicular approach, 32 underwent the transaxillary approach, and 7 underwent the transaxillary approach followed by the supraclavicular approach. Complications were evaluated over 24 months. Results: The prevalence of pneumothorax, hemothorax, and vessel injuries in the transaxillary and the supraclavicular approaches was equal. We found more permanent and transient brachial plexus injuries in the case of the transaxillary approach than in the case of the supraclavicular approach, but the difference was not statistically significant. Persistent pain and symptoms were significantly more common in patients who underwent the transaxillary approach (p<0.05). Conclusion: The supraclavicular approach seems to be the more effective technique of the two because it offers the surgeon better access to the brachial plexus and a direct view. This approach for a TOS operation offers a better surgical outcome and lower reoperation rates than the transaxillary method. Our results showed the supraclavicular approach to be the preferred method for TOS operations.

• Fire Science and Engineering
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• v.27 no.5
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• pp.8-14
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• 2013

In the subway, various fires continue to take place across the world. In the Daegu subway accident in 2003, many people were damaged by shortened visibility range caused by toxic gas and smoke. This paper, assuming that a subway fire happens in the Mandeok Station of the subway system in Busan, analyzed different smoke-spreading situations depending on the ventilation situation at its platform (opening of the train doors, operation of ventilation facilities in the tunnel, and working of fire door), using FDS. The calculation proved that it would be more effective to secure evacuation route when the ventilation facilities of the tunnel are not operated, than when they are on. And, it was also found that the case where the doors of the platform to the escape route and only the platform-facing doors of the subway car on fire office are open would be more effective to ventilation than the case where all the doors are open. And, it was found to be important that the fire doors of the platform are working properly.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.73-83
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• 2012

Effective use of traffic marking can lead to driver's safer driving by speed management and visibility enhancement. One of the critical factors in designing traffic marking is how to incorporate human factor issues into the design process. This study presented a methodology for evaluating the effectiveness of Hi-pass marking on Korean freeways based on kansei engineering. Hi-pass marking scenarios made by a virtual reality tool were used to evaluate the user's perceptions. Various combination of chevron angles and peripheral transverse(PT) bars were used for the evaluation. The results show that the most effective scenario is a combination of 60 degree chevron angle and an askew parallelogramshaped PT bar shaped. It is expected that the proposed method and outcome will be useful for making safer driving maneuvers.

• YAKHAK HOEJI
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• v.53 no.6
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• pp.328-333
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• 2009

Contrast media are substances that are used to enhance the contrast of structures or fluids within the body in medical imaging. Those are commonly used to enhance the visibility of blood vessels and the gastrointestinal tract. The aim of this study is to evaluate patients who got injected iopamidol, developed as one of contrast medium regarding changes in cardiovascular system and especially, adverse drug reactions. This study were performed on randomly selected a total of 51 patients (range of 15~85 years old) who got injected contrast medium, Iopamidol at a P hospital in Gyeonggi province from September 22nd, 2008 to January 24th, 2009. Data were collected by questionnaire though person to person. We analyzed the data by SPSS (Version 12. for windows). Methods of analysis were frequency and cross analysis. In results, 19.6% (n=10) were founded for adverse drug reactions of contrast medium. 25.0% (n=4) of 10 patients who had adverse drug reactions of contrast medium had took abdomen contrast test. 2 patients of those took contrast test for chest. Also, 3.9% (n=2) patients felt vomiting and nausea after injection of contrast medium. In conclusion, 19.6% patients experienced adverse drug reaction of contrast medium. Therefore, when taking radiation test, we should make efforts to minimize adverse drug reactions to achieve suitable and effective treatment.

• Fire Science and Engineering
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• v.25 no.6
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• pp.120-126
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• 2011

Recently luminous egress guide-lines are introduced for the fire safety of residents in the multi-use buildings such as Gosiwon. Little literature, however, on the quantitative and qualitative estimation for the egress performance of the luminous egress guide-lines can be found. This study carried out experimental investigations to evaluate the egress performance of the existing egress guide-lights and new luminous egress guide-lines. The results showed that both luminous egress guide-lines and egress guide-light satisfied the basic performance of KFI requirements. Under the 7 % smoke transmittance, however, luminous egress guide-lines showed 3 times longer visibility and less evacuation time than egress guide-lights. The evacuation density and smoke transmittance have significant effect on the evacuation time increase without the luminous egress guide-lines, however little effect with the installation.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.62-67
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• 2004

Many ships in voyage experience weight and buoyancy distribution change by various reasons such as change of sea water density and waves, weather condition, and consumption of fuel, provisions, etc . The weight and buoyancy distribution change can bring the ships out of allowable trim, heeling angle. In these case, the ships should adjust trim and heeling angle by shifting of liquid cargo or ballasting, deballasting of ballast tanks for recovery of initial state or for a stable voyage. But, if the adjustment is performed incorrectly, ship's safety such as longitudinal strength, intact stability, propeller immersion, wide visibility, minimum forward draft cannot be secured correctly. So it is required that the adjustment of trim and heeling angle should be planned not by human operators but by optimization computer algorithm. To make an optimized plan to adjust trim and heeling angle guaranteeing the ship's safety and quickness of process, Uk! combined mechanical analysis and optimization algorithm. The candidate algorithms for the study were heuristic algorithm, meta-heuristic algorithm and uninformed searching algorithm. These are widely used in various kinds of optimization problems. Among them, heuristic algorithm $A^\ast$ was chosen for its optimality. The $A^\ast$ algorithm is then applied for the study. Three core elements of $A^\ast$ Algorithm consists of node, operator, evaluation function were modified and redefined. And we analyzed the $A^\ast$ algorithm by considering cooperation with loading instrument installed in most ships. Finally, the algorithm has been applied to tanker ship's various conditions such as Normal Ballast Condition, Homo Design Condition, Alternate Loading Condition, Also the test results are compared and discussed to confirm the efficiency and the usefulness of the methodology developed the system.

• Imaging Science in Dentistry
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• v.47 no.3
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• pp.199-207
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• 2017

Purpose: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Materials and Methods: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Results: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Conclusion: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.301-310
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• 2021

The purpose of the study was to induce meaning of the UX design from users' interview. The study covers interviews from 20 untact finance application users in their twenties in written form. It aims to examine previous studies on UX design and to overcome their shortcomings by categorizing usability qualities focusing on verbs used in the interview. The followings are the result: Usability of UX design can be summarized into Unity, Trust, Persistency, Recognition and Approachability of the information to the 20 users in their twenties. As for the data earned from interviews focusing on verbs, usability included Security, Familiarity, Accessibility, Convenience of Operation and Visibility. Each of the qualities fell into related categories such as Security, Information, Brand and Design. In conclusion, analysis based on verb choices led to better understanding of the user-based experience compared to using objective means in previous studies and can be a suggestion to make up for errors in the former evaluation process.