• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.1069-1074
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• 2022

IP mobility can be handled in different layers of the protocol. Mobile IP has been proposed to handle the mobility of Internet hosts in the network layer. Recently, a new method based on the SIGMA mobility architecture has been proposed to support mobility management with reduced packet loss and latency. The location management structure is not suitable for frequent mobile handover due to the high mobility of the user with this transport layer solution. In this paper, we propose a location management optimization method in a mobile communication network by applying hierarchical location management using MMPs(Mobility Management Points) for transport layer mobility management. Therefore, we propose an efficient hierarchical mobility management structure even between heterogeneous wireless networks using MMPs for the probability that a mobile terminal can change multiple location areas between two messages and calls. The proposed method shows reduction in location update cost and data retrieval cost using MMPs, and as opposed to mobility appearing in time intervals with the minimum cost required to reach 90% of the stabilized cost, the mobility location update search, location It was found that the message processing cost per area was reduced.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.33-42
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• 2019

In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape of Korean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite images were referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on the measured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying these developed equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to the measured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the current SWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differences were caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected the water quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water quality simulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate water quantity / quality and water ecosystem simulation using hydrological model.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.877-885
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• 2004

In this paper, we propose an enhancement shot change detection method using the neural net and the robust feature selection out of multiple features. The previous shot change detection methods usually used single feature and fixed threshold between consecutive frames. However, contents such as color, shape, background, and texture change simultaneously at shot change points in a video sequence. Therefore, in this paper, we detect the shot changes effectively using robust features, which are supplementary each other, rather than using single feature. In this paper, we use the typical CART (classification and regression tree) of data mining method to select the robust features, and the backpropagation neural net to determine the threshold of the each selected features. And to evaluation the performance of the robust feature selection, we compare the proposed method to the PCA(principal component analysis) method of the typical feature selection. According to the experimental result. it was revealed that the performance of our method had better that than the PCA method.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.252-264
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• 2008

Objective: To aid the development of a frontal image simulating program, we evaluated the soft tissue frontal changes in relationship to movement of hard tissue with orthognathic surgery of facial asymmetry patients. Methods: Preoperative and postoperative frontal cephalograms and frontal view photographs of 45 mandibular surgery patients with facial asymmetry were obtained in a standardized manner. Vertical and horizontal changes of hard tissue and soft tissue were measured from cephalograms and photographs, respectively. Soft tissue change in result to hard tissue change was then analyzed. Results: Both vertical and horizontal correlation analysis showed a weak relationship between the changes. Hard tissue points that were picked for 1 : 1 mean ratio with soft tissue points did not show any significant relevance. For each soft tissue change, regressive equation was formulated by stepwise multiple regression analysis, and the equation for soft tissue Menton was most reliable in predicting changes. Both vertical and horizontal hard tissue changes were used together in prediction of vertical or horizontal soft tissue change. Conclusions: The results suggest that computerized image simulation using regression analysis may be of help for prediction of soft tissue change, while 1:1 mean ratio method is not useful.

• ETRI Journal
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• v.36 no.1
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• pp.1-11
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• 2014

In this paper, we propose a distributed synchronization algorithm for wireless mesh networks based on orthogonal frequency division multiple access. For time and frequency synchronization, a node requests its neighbor nodes for a change of fast Fourier transform starting points, transmission times, and carrier frequencies needed for synchronization. The node also updates its own time and frequency elements through simple formulas based on request messages received from neighbor nodes using a guard interval and a cyclic prefix. This process with the cooperation of neighbor nodes leads to a gradual synchronization of all nodes in the network. Through a performance comparison with a conventional scheme, we obtain simulation results indicating that the proposed scheme outperforms the conventional scheme in random topologies and a grid topology.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.2
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• pp.106-119
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• 2005

Uncertainties inherent in customer demand patterns make it difficult for supply chains to achieve just-in-time inventory replenishment, resulting in loosing sales opportunity or keeping excessive chain wide inventories. In this paper, we propose two intelligent adaptive inventory control models for a supply chain consisting of one supplier and multiple retailers, with the assumption of information sharing. The inventory control parameters of the supplier and retailers are order placement time to an outside source and reorder points in terms of inventory position, respectively. Unlike most extant inventory control approaches, modeling the uncertainty of customer demand as a stationary statistical distribution is not necessary in these models. Instead, using a reinforcement learning technique, the control parameters are designed to adaptively change as customer demand patterns change. A simulation based experiment was performed to compare the performance of the inventory control models.

• Journal of Korean Neurosurgical Society
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• v.52 no.3
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• pp.172-178
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• 2012

Objective : The aim of this study was to determine the role of intra-arterial (IA) nimodipine injections for cerebral vasospasm secondary to ruptured subarachnoid hemorrhage (SAH) and to investigate the factors that influence vasodilation and clinical outcomes. Methods : We enrolled 29 patients who underwent aneurysm clipping for ruptured cerebral aneurysms between 2009 and 2011, and who received IA nimodipine after subsequently presenting with symptomatic vasospasm. The degree of vasodilation shown in angiography was measured, and the correlation between the degree of vasodilation and both the interval from SAH to cerebral vasospasm and the interval from clipping to cerebral vasospasm was determined. The change in blood flow rate after IA injection was assessed by transcranial Doppler ultrasound. Multiple clinical parameters were completed before and after IA nimodipine injection to evaluate any improvements in clinical symptoms. Results : For eight patients, Glasgow Coma Scale (GCS) scores increased by two or more points. The regression analysis demonstrated a positive correlation between the change in GCS scores after IA nimodipine injection and the change in blood vessel diameter (p=0.025). A positive correlation was also observed between the interval from SAH to vasospasm and the change in diameter (p=0.040); and the interval from clipping to vasospasm and the change in diameter (p=0.022). Conclusion : IA nimodipine injection for SAH-induced vasospasm led to significant vasodilation in angiography and improvement in clinical symptoms without significant complications. Our findings suggest that IA nimodipine injection should be utilized when intractable vasospasm develops despite rigorous conservative management.

• Journal of Korean Clinical Health Science
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• v.6 no.2
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• pp.1156-1170
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• 2018

Purpose. This study was conducted to analyze fatigue and subjective oral health status in the employees in educational institutions and provide basic data for the development of a program for the promotion of oral health. Methods. As for the subjects, this study conducted a survey with 468 educational personnel in elementary, middle, and high schools in the Daegu-Gyeongbuk area from March through June 2016 and utilized 407 copies finally. As for the items on the survey, this study conducted an investigation on their general characteristics, fatigue, and subjective oral health status(halitosis, xerostomia, temporomandibular disorder) with the self-administered method. With the data collected, this study conducted frequency analysis, t-test, ANOVA, and multiple regression analysis, using SPSS 20.0 statistical program, and the statistical significance level was .05. Results. As a result of this study, it turned out that by sex, fatigue was higher in women(4.59 points); by the place of work, those in 'elementary school' had higher fatigue(4.59 points); and by health condition and oral health status, most of them responded that they were 'not healthy'(4.81 and 4.84 points, respectively) and there was a statistically significant difference (p<.05). As for the correlation between fatigue and subjective oral health status, there were positive(+) impacts on halitosis(=.248, p<.001), xerostomia(=.097, p<.05), and temporomandibular disorder(=.148, p<.01), so it turned out that there was a correlation between fatigue and subjective oral health status. Conclusion. Based on the result of an analysis of the impacts of the fatigue level on subjective oral health status, it is judged that it would be necessary to continue to build up a program that can promote the oral health status of the educational personnel. In addition, it is necessary to conduct studies continuously for the development and application of a program for the change in lifestyle and behavior that can lower their fatigue.

• Journal of Korean Academy of Nursing
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• v.31 no.2
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• pp.206-220
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• 2001

The purpose of this study was to investigate the impact of depression, discomfort, spirituality, physical care, and opioid use on pain with terminally ill cancer patients residing in hospice units. The convenient sample of this study consisted of 41 terminally ill cancer patients at three hospice units in university affiliated hospitals. Patients were interviewed with structured questionnaires three times at predetermined intervals: admission to the hospice unit (Time 1), one week later (Time 2), and two weeks later (Time 3). The data was collected from January 1998 to January 1999 and was analyzed using ANOVA, Pearson correlation coefficient, and multivariate multiple regression. 1. The mean age of the participants was approximately 55 years old. In terms of diagnosis, lung cancer showed the highest frequency (19.5%), followed by stomach cancer and rectal cancer (17.1%). The motive of seeking hospice unit admission was control (72. 2%), followed by spiritual care (50%), and symptom relief (38.9%). 2. Regarding the type of pain felt, the highest pain frequency the participants experienced was deep pain (55%), followed by multiple pain (25%), intestinal pain (10%), then superficial (5%) and neurogenic pain (5%). For the level of pain measured by VAS, there was no significant difference among the three time points; Time 1 (5.04$\pm$2.21), Time 2 (4.82$\pm$2.58) and Time 3(4.73$\pm$2.51). 3. There was significant change seen in spirituality and physical care in each time interval. Namely, the longer the length of admission at the hospice unit, the higher the importance of spirituality (p=0.0001) and the more the physical care the participants received (p=0.01). The opioid use at the three time points showed the following frequencies : Time 1 (75.6%), Time 2 (85.4%) and Time 3 (75.6%). 4. Regarding factors influencing pain, the pain level was significantly affected by the depression level (p〈0.01) and the opioid use (p〈0.1). These results were the most significant at the two time points (Time 1 and Time 2). At Time 3 (two weeks later), the pain level was significantly affected by the depression level (p〈0.05) and the amount of physical care the participants received (p〈0.1). In conclusion, the terminally ill cancer patients had moderate pain, were generally depressed, and were treated with opioid analgesics. As approaching death, the patients received more physical care due to increased physical symptoms experienced and they had a higher perception of the importance of spirituality. Thus, health care professionals need to provide continuous care for each of them to die comfortably physically, psycho- logically, and spiritually.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.47-58
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• 2002

This thesis is based on the speed variations which are observed both in a sing1e tunnel and a continuous tunnel. Kumdae II tunnel and Chiak I tunnel of Jungang Expressway are selected in order to analyze the characteristics of speed variations according to tunnel intervals I place importance on the computation of tunnel intervals according to the speed variations. there's a summary of the results. The results of the study reveal that speed changes occur both on 1km ahead of tunnel and within the tunnel. The speed change amounts to 7.1km/hr(6.7%) on these survey Points 2.7km/hr (2.9%) on access points, and from -3.6km/hr (-3.8%) to, +4.1km/hr(+4.7%) irregularly on egress points. The magnitude of speed chance appears small on the survey points where an interval of tunnel is short whereas the speed chance turn out to be rather significant on the points where the tunnel interval is long. The analysis of tunnel distances using multiple regression models shows that the appropriate tunnel distance turns out to be 732m. The distance of 732m seem to be providing a fecundation for uniform traffic flow in continuous tunnel conditions.