• Journal of Biomedical Engineering Research
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• v.35 no.3
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• pp.50-54
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• 2014

It is being tried to control robot arm using brain signal in the field of brain-machine interface (BMI). This study is focused on applying guidance laws for efficient robot arm control using 3D coordinates obtained from Magnetoencephalography (MEG) signal which represents movement of upper limb. The 3D coordinates obtained from brain signal is inappropriate to be used directly because of the spatial difference between human upper limb and robot arm's end-effector. The spatial difference makes the robot arm to be controlled from a third-person point of view with assist of visual feedback. To resolve this inconvenience, guidance laws which are frequently used for tactical ballistic missile are applied. It could be applied for the users to control robot arm from a first-person point of view which is expected to be more comfortable. The algorithm which enables robot arm to trace MEG signal is provided in this study. The algorithm is simulated and applied to 6-DOF robot arm for verification. The result was satisfactory and demonstrated a possibility in decreasing the training period and increasing the rate of success for certain tasks such as gripping object.

• Tuberculosis and Respiratory Diseases
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• v.63 no.1
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• pp.24-30
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• 2007

Background: Pleural effusion develops in approximately 40% of pneumonia patients. In 5-10% of these cases, it progresses to complicated parapneumonic effusion (CPPE) or empyema that requires drainage. The prognostic factors of CPPE and empyema remain to be clarified. We examined the treatment outcomes of CPPE and empyema and elucidating their prognostic factors. Methods: One hundred and fifteen patients with CPPE or empyema, who were diagnosed and treated in Kyungpook National University Hospital (Daegu, Korea) between September 2001 and December 2005, were retrospectively analyzed. All the data was acquired from their chart review, and regarding treatment results, the time to defervescence and the length of hospital stay were analyzed. Results: The treatment was successful in 101 patients with a success rate of 87.8%. Multivariate analysis showed the level of pleural fluid lactate dehydrogenase (LDH) to be a significant prognostic factor (odds ratio [OR] 7.37; 95% confidence interval [CI], 1.63 to 33.37; p=0.009). Pussy pleural fluid (r=0.236; p=0.01) and the frequency of urokinase use (r=0.257; p=0.01) correlated with the time to defervescence. However, there was no clinical factor that correlated with the length of hospital stay. Conclusion: The pleural fluid LDH level is a useful prognostic factor for monitoring treatment results of CPPE and empyema.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1053-1063
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• 2011

Social network analysis is the social statistical analysis of any social structure involving a stream of mutual information between observations. In this study we used the results of passes between players in a soccer game. The analysis contents are as follows. (1) Players with important or leading roles are identified. (2) Players are assessed by pass frequency and the success rate of passes. The purpose of this study is for use as basic data for future team strategy, and achieves this by evaluating the role of each individual player within a team. In this study, social network analysis without separating positions is conducted, and is also performed for defensive and attacking positions respectively. The results of this study are as follows: First, when complete team data were available, the players performing leadership roles were Jung-woo Kim, Sung-yeung Ki and Chung-young Lee, whereas Jeong-su Lee acted as a sub-leader. In case of data for defensive positions Jeong-su Lee was a leading player, and in terms of attacking positions, all of the players excelled in the game and could be evaluated as playing lead roles.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.25-53
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• 2022

In this study, trends in research methods and topics of seabird and marine fish migration were examined. Based on the framework of existing animal migration studies, future research directions were proposed in relation to the migration of seabirds and fish. In terms of research methodology, with the development of science and technology, tracking techniques using radio telemetry, acoustic telemetry, RFID (radio-frequency identification), satellite tracking, and geolocators are widely used to study seabird and fish migration. Research is also conducted indirectly through a population survey and the analysis of substances in the body. Research contents are largely classified into extrinsic factors that affect migration(such as environmental variables and interspecific competition), intrinsic factors such as hormones, anthropogenic activities including fishery and offshore wind farm, and the effect of global climate change. In future studies, physiological factors that influence or cause migration and dispersal should be identified concerning intrinsic factors. For the analysis of migration ability, it is necessary to study effects of changes in the magnetic field on the migration ability of seabirds and fish, interspecific differences in spatiotemporal migration ability, and factors that influence the migration success rate. Regarding extrinsic factors, research studies on effects of anthropogenic disturbances such as fishery and offshore wind farm and global climate change on the migration and dispersal patterns of marine animals are needed. Finally, integrated studies on the migration of seabirds and fish directly or indirectly affecting each other in various ecological aspects are required.

• Information Systems Review
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• v.22 no.1
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• pp.125-146
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• 2020

With the penetration of the Internet and e-commerce, a 'crowdfunding' has emerged as a new way of financing. Crowdfunding has the advantage for a person to able to a simple way to finance her/his an innovative product or service from crowd. However, the success rate for crowdfunding projects is less than half. In this study, we introduce social exchange theory to explore the impact of trust and perceived psychological risk on the intention to participate in a crowdfunding website. Different from previous studies that have focused on a crowdfunding creator, we consider two different perspectives of a project creator and a project supporter. In addition, we compare perceptions of crowdfunding in different cultural contexts by conducting survey in two different countries Korea and Austria. Result shows that trust in recommendation and trust in website have different impacts on the intention to participate from two different perspectives. It also shows that perception of the quality and transparency of information provided by crowdfunding website has greater impact on trust in Korea than that in Austria. In case of perception of psychological risk, it has a negative impact on Austria's intention to create or support a project. On the other hand, it has relatively small impact on the intention to support and does not affect the intention to create a project in Korea.

• Korean Circulation Journal
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• v.53 no.7
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• pp.483-496
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• 2023

Background and Objectives: Atrial fibrillation (AF) is associated with decreased cardiac resynchronization therapy (CRT) benefits compared to sinus rhythm (SR). Effective biventricular (BiV) pacing is a determinant of CRT success, but AF can interfere with adequate BiV pacing and affect clinical outcomes. We investigated the effect of device-detected AF on clinical outcomes and optimal BiV pacing in patients with heart failure (HF) treated with CRT. Methods: We retrospectively analyzed 174 patients who underwent CRT implantation between 2012 and 2019 at a tertiary center. The optimal BiV pacing percentage was defined as ≥98%. Device-detected AF was defined as an atrial high-rate episode ≥180 beats per minute lasting more than 6 minutes during the follow-up period. We stratified the patients without preexisting AF at pre-implantation into device-detected AF and no-AF groups. Results: A total of 120 patients did not show preexisting AF at pre-implantation, and 54 had AF. Among these 120 patients, 19 (15.8%) showed device-detected AF during a median follow-up of 25.1 months. The proportion of optimal BiV pacing was significantly lower in the device-detected AF group than in the no-AF group (42.1% vs. 75.2%, p=0.009). The devicedetected AF group had a higher incidence of HF hospitalization, cardiovascular death, and all-cause death than the no-AF group. The device-detected AF and previous AF groups showed no significant differences regarding the percentage of BiV pacing and clinical outcomes. Conclusions: For HF patients implanted with CRT, device-detected AF was associated with lower optimal BiV pacing and worse clinical outcomes than no-AF.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.250-262
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• 2007

Statement of problem: It was reported high success rate of implant-supported fixed prostheses using with $5{\sim}6$ implants on anterior mandible. Recently, immediate loading protocol was focused to overcome disadvantages of classic 2-stage delayed loading protocol. Purpose: This clinical study was to evaluate stability changes with time of immediately loaded and delayed loaded implants in edentulous mandible and to compare stability changes with time according to implantation sites. Materials and methods: Five or six implants were placed on anterior mandible depending on the arch shape. The immediately loading group was consisted of 8 patients received their prostheses within $24{\sim}48$ hours after implantation. The delayed loading group was consisted of 8 patients received their definitive prostheses following classical prosthetic procedures after a healing period of 3 months. All patients were recalled every 6 months for check-up. The evaluations of radiographic examination, ISQ value measurement and recording of complication were done. To evaluate marginal bone level, intraoral periapical radiographs were taken with long cone paralleling technique. At every evaluation recall, all prostheses were removed and ISQ values were measured with OsstellTM on individual implants. Results: 1. None of implants was failed. All implants showed stable marginal bone levels and ISQ values. 2. Marginal bone level changes with time showed statistically significant difference between immediately loading group and delayed loading group (P<0.001). 3. ISQ value changes with time did not show statistically significant difference between immediately loading group and delayed loading group (P=0.079). ISQ value decreased with time in both groups, however, all implants showed stable ISQ value at 30 months-recall evaluation. 4. Marginal bone level changes with time did not show statistically significant differences among implantation sites (P=0.604). 5. ISQ value changes with time showed statistically significant differences among implantation sites (P=0.047). ISQ values of most posterior implants decreased with time comparing to other implants. Conclusion: Although the marginal bone level of the terminal abutment didn't different with the other implants, ISQ value of the terminal abutment was lower than that of the other implants. Therefore, further clinical evaluation would be needed in this point of view.

• Journal of Oral Medicine and Pain
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• v.37 no.4
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• pp.221-225
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• 2012

Disc dislocation without reduction, as known as closed lock, is a clinical condition in which the disc is dislocated from the condyle and does not return to normal position during condylar movement When the condition of disc dislocation without reduction is acute, the initial therapy should include an attempt to reduce or recapture the disc by manual manipulation. When patients report a history of being locked for 1 week or less, manual manipulation is usually successful. In patients with a longer history, success rate tends to decrease rapidly. If the disc has been successfully recaptured, placing an anterior positioning appliance is recommended to prevent clenching on the posterior teeth, which would likely redislocated the disc. But it is hard to make an appliance immediately in the clinic because it takes too much time. And making an appliance using self-curing acrylic resin is not very popular because of its discomfort by odor and working time. Also, if the patient has resin allergy or is under orthodontic treatment, or if it is impossible to control behavior of the patient, it has been restricted to make an appliance immediately. Therefore, to supplement this disadvantages, we tried to confirm about successful short term use of temporary anterior positioning splint made by using putty impression material after manual manipulation in this study.

• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.35-48
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• 2010

For the next generation mobile communication system, diverse wireless network techniques such as beyond 3G LTE, WiMAX/WiBro, and next generation WLAN etc. are proceeding to the form integrated into the All-IP core network. According to this development, Beyond 3G integrated into heterogeneous wireless access technologies must support the vertical handover and network to be used of several radio networks. However, unified management of each network is demanded since it is individually serviced. Therefore, in order to solve this problem this study is introducing the theory of Common Radio Resource Management (CRRM) based on Generic Link Layer (GLL). This study designs the structure and functions to support the vertical handover and propose the vertical handover algorithm of which policy-based and MCDM are composed between LTE and WLAN systems using GLL and CRRM. Finally, simulation results are presented to show the improved performance over the data throughput, handover success rate and the system service cost.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.889-900
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• 2022

Objective: To investigate the long-term outcomes of percutaneous treatment of benign biliary strictures using temporary placement of a retrievable expanded polytetrafluoroethylene (PTFE) covered stent. Materials and Methods: We retrospectively analyzed the outcomes of 148 patients (84 male and 64 female; age range, 11-92 years) who underwent percutaneous transhepatic placement and removal of a retrievable PTFE-covered stent for the treatment of benign biliary strictures between March 2007 and August 2019 through long-term follow-up. Ninety-two patients had treatment-naïve strictures and 56 had recurrent/refractory strictures. Results: Stent placement was technically successful in all 148 patients. The mean indwelling period of the stent was 2.4 months (median period, 2.3 months; range, 0.2-7.7 months). Stent migration, either early or late, occurred in 28 (18.9%) patients. Clinical success, defined as resolution of stricture after completing stent placement and removal, was achieved in 94.2% (131 of 139 patients). The overall complication rate was 15.5% (23 of 148 patients). During the mean follow-up of 60.2 months (median period, 52.7 months; range, 1.6-146.1 months), 37 patients had a recurrence of clinically significant strictures at 0.5-124.5 months after removal of biliary stent and catheter (median, 16.1 months). The primary patency rates at 1, 3, 5, 7, and 10 years after removal of biliary stent and catheter were 88.2%, 70.0%, 66.2%, 60.5%, and 54.5%, respectively. In the multivariable Cox proportional hazard regression analysis, sex, age, underlying disease, relation to surgery, stricture type, biliary stones, history of previous treatment, and stricture site were not significantly associated with the primary patency. Conclusion: Long-term outcomes suggest that percutaneous treatment of benign biliary strictures using temporary placement of retrievable PTFE-covered stents may be a clinically effective method.