• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.39-47
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• 2015

In this paper, we propose a new time synchronization algorithm using CoAP(constrained-application protocol) in sensor network environment, which handles a technique that synchronizes an explicit timestamp between sensor nodes not including an additional module for time-setting and sensor node gateway linked to internet time server. CoAP is a standard protocol for sensor data communication among sensor nodes and sensor node gateway to be built much less memory and power supply in constrained network surroundings including serious network jitter, packet losses, etc. We have supplied an exact time synchronization implementation among small and cheap IP-based sensor nodes or non-IP based sensor nodes and sensor node gateway in sensor network using CoAP message header's option extension. On behalf of conventional network time synchronization method, as our approach uses an exclusive protocol 'CoAP' in sensor network, it is not to become an additional burden for synchronization service to sensor nodes or sensor node gateway. This method has an average error about 2ms comparing to NTP service and offers a low-cost and robust network time synchronization algorithm.

• Composites Research
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• v.23 no.3
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• pp.19-30
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• 2010

The present study describes a method for analytical solution to elastic field in structural elements of general symmetric laminated composite materials. The two dimensional plane stress elasticity problems under mixed boundary conditions are reduced to the solution of a single fourth order partial differential equation, expressed in terms of a single unknown function, called displacement potential function. In addition, all the components of stress and displacement are expressed in terms of the same displacement potential function, which makes the method suitable for any boundary conditions. The method is applied to obtain analytical solutions to two particular problems of structural elements consisting of an angle-ply laminate and a cross-ply laminate, respectively. Some numerical results are presented for both the problems with reference to the glass/epoxy composite. The results are highly accurate and reliable as all the boundary conditions including those in the critical regions of supports and loads are satisfied exactly. This verifies the method as a simple and reliable one as well as capable to obtain exact analytical solution to elastic field in structural elements of composite materials under mixed and any other boundary conditions.

• Journal of Korean Society of Forest Science
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• v.83 no.3
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• pp.322-330
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• 1994

The Universal Soil Loss Equation (USLE) has been widely used to predict long-term soil loss by incorporating several erosion factors, such as rainfall, soil, topography, and vegetation. This study is aimed to introduce the LISLE within geographic information system(GIS) environment. The Kwangneung Experimental Forest located in Kyongki Province was selected for the study area. Initially, twelve years of hourly rainfall records that were collected from 1982 to 1993 were processed to obtain the rainfall factor(R) value for the LISLE calculation. Soil survey map and topographic map of the study area were digitized and subsequent input values(K, L, S factors) were derived. The cover type and management factor (C) values were obtained from the classification of Landsat Thematic Mapper(CM) satellite imagery. All these input values were geographically registered over a common map coordinate with $25{\times}25m^2$ ground resolution. The USLE was calculated for every grid location by selecting necessary input values from the digital base maps. Once the LISLE was calculated, the resultant soil loss values(A) were represented by both numerical values and map format. Using GIS to run the LISLE, it is possible to pent out the exact locations where soil loss potential is high. In addition, this approach can be a very effective tool to monitor possible soil loss hazard under the situations of forest changes, such as conversion of forest lands to other uses, forest road construction, timber harvesting, and forest damages caused by fire, insect, and diseases.

• The Journal of Information Systems
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• v.24 no.3
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• pp.133-154
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• 2015

Purpose This study re-analyzes Jung 2012's data using the time interval based analysis to examine if the process of idea generation is in good currency throughout the ideation sessions. In this way, the relationship between extraversion-introversion personality trait and ideation performance in the context of computer-mediated idea generation can be better understood. Design/methodology/approach A $2{\times}4$ factorial design was used, crossing personality differences (extraversion and introversion) with the degree of stimuli (0, 20, 40, and 80 high-quality ideas). Participants were randomly assigned to one of eight treatment conditions. The group simulator is used to measure individual level performance. The number of unique ideas generated by individuals and the exact time stamp when each idea was submitted were analyzed to compare performances. Findings The results show that introverts' performances significantly drops after about the middle stage of the ideation session, whereas extraverts do not seem to feel time constraints throughout the ideation session, resulting in superior divergent thinking, which is a major key to understand creative productivity in the problem-solving process. Since extraverts tend to yield a larger pool of ideas, another interpretation is that group composition with extraverts compared with introverts may create a logically larger group, which is important to improve the performance of idea generation group.

• Journal of Chest Surgery
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• v.8 no.1
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• pp.19-28
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• 1975

The thoracoscopic study was reported on 21 cases of spontaneous pneumothorax requiring surgical management, and clinical values of thoracoscopic examination on spontaneous pneumothorax were also discussed. patients were treated in the Department of .Thoracic Surgery, Hanyang University Hospital for the period of two Years from May 1972 to April 1974. For exact detection of etiologic factors on spontaneous pneumothorax, the thoracoscopic examination in the intrapleural space was performed in parallel with X-ray study. this study, the difference of diagnostic and therapeutic significance between radiological and thoracoscopic findings were observed and compared simultaneously. The results are summerized as follows: Patients age was distributed between 3 and 70 years old with highest incidence in the age group of sixty decade [33. 3%], and sex ratio of male to female was 5:2. The tuberculous processes which developed superficial subpleural layer in the lung parenchyme, on the pulmonary surface could be observed by thoracoscopic examination in a characteristic picture. detection ratio of pulmonary tuberculosis by the radiologic study to that by thoracoscopy was 8:2. The adhesion between the visceral and the parietal pleura which could possibly make a rupture of the alveola and the visceral pleura was found to be localized in a small area of the lung surface. The other part of the lung surface was free of the adhesion and, therefore, the movement of the lung took place completely without any difficulty. The ruptured orifice of the pleura and pathological changes surrounding the orifice can be detected by thoracoscopy, but not by other means such as radiologic examination. A single tuberculous bleb and multiple emphysematous blebs were found on 6 cases out of 21 cases of spontaneous pneumothorax. Among these cases, radiologic Study revealed the bleb only in one patient. On the other hand, the blebs were found in all the six patients by means of thoracoscopic examination. It gives the detection ratio of bleb by radiologic study to that by thoracoscopy was 1:6. By thoracoscopy, the rupture on the lung surface were visualized on the 10 patients out of a total of 21 patients [10 patients of visual rupture]. However, the rupture of the pleura was not observed on the rest of 11 patients even by thoracoscopic examination [11 patients of non visual rupture]. Five patients [50%] out of ten who had the visual rupture on the lung surface was required a surgical operation to remove pneumothorax. For the patients who were detected to have the visual rupture of the pleura by thoracoscopy, be considered in the early stage of closed thoracostomy. of 21 patients, 16 patients [11 patients of non visual rupture of the pleura and 5 patients of visual rupture of the pleura] who received no surgical management, were treated with closed thoracostomy with continuous suction, and the` pneumothorax was healed completely up in each cases. Therapeutic measures for the remaining 5 patients of visual rupture of the pleura who were subjected to surgical approach for radical treatment of spontaneous pneumothorax were accordingly complicated, and the following different procedures were properly indicated case by case, that is, rib resection thoracostomy, simple closure of ruptured visceral pleura, wedged resection of the lung, and lobectomy.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.764-774
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• 2013

In this study we reviewed how acid rain as the global environmental problems was dealt with geography textbooks from Korea and England. The results are as follows. First, unlike geography textbooks from England, the concept and criteria of acid rain are not explained exactly in Korea geography textbooks. Second, whereas the cause of acid rain was explained with natural and artificial factors in geography textbooks from England, in Korea the artificial factors only were explained. But if the artificial factors only will be introduced to students, they may misunderstand about the acid rain. Third, the results and policies of acid rain were provided in geography textbooks from Korea and England. But whereas they were deal with separately in Korea, in textbooks from England they were provided with their patterns and concrete cases. So it is necessary to provide the exact concept, results and processes of the global environmental problems structurally in geography textbooks. And it is necessary to provide the results and their policies of the global environmental problems with concrete cases for students' understanding and sympathy about them. If the concepts and causes of global environmental problems are not understood previously, it is possible to stimulate only the moral and ethical aspects too much when the results and policies of them is introduced in geography textbooks.

• Journal of KIISE:Software and Applications
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• v.34 no.1
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• pp.1-10
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• 2007

This paper proposes a new indexing mechanism for MPEG-7 visual descriptors, especially Dominant Color and Contour Shape descriptors, that guarantees an efficient similarity search for the multimedia database whose visual meta-data are represented with MPEG-7. Since the similarity metric used in the Dominant Color descriptor is based on Gaussian mixture model, the descriptor itself could be transform into a color histogram in which the distribution of the color values follows the Gauss distribution. Then, the transformed Dominant Color descriptor (i.e., the color histogram) is indexed in the proposed indexing mechanism. For the indexing of Contour Shape descriptor, we have used a two-pass algorithm. That is, in the first pass, since the similarity of two shapes could be roughly measured with the global parameters such as eccentricity and circularity used in Contour shape descriptor, the dissimilar image objects could be excluded with these global parameters first. Then, the similarities between the query and remaining image objects are measured with the peak parameters of Contour Shape descriptor. This two-pass approach helps to reduce the computational resources to measure the similarity of image objects using Contour Shape descriptor. This paper also proposes two integration schemes of visual descriptors for an efficient retrieval of multimedia database. The one is to use the weight of descriptor as a yardstick to determine the number of selected similar image objects with respect to that descriptor, and the other is to use the weight as the degree of importance of the descriptor in the global similarity measurement. Experimental results show that the proposed indexing and integration schemes produce a remarkable speed-up comparing to the exact similarity search, although there are some losses in the accuracy because of the approximated computation in indexing. The proposed schemes could be used to build a multimedia database represented in MPEG-7 that guarantees an efficient retrieval.

• The Korean Journal of Pain
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• v.27 no.3
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• pp.278-284
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• 2014

Background: Establishment of laparoscopic cholecystectomy as an outpatient procedure has accentuated the clinical importance of reducing early postoperative pain, as well as postoperative nausea and vomiting (PONV). We therefore planned to evaluate the role of a multimodal approach in attenuating these problems. Methods: One hundred and twenty adult patients of ASA physical status I and II and undergoing elective laparoscopic cholecystectomy were included in this prospective, randomized, placebo-controlled study. Patients were divided into four groups of 30 each to receive methylprednisolone 125 mg intravenously or etoricoxib 120 mg orally or a combination of methylprednisolone 125 mg intravenously and etoricoxib 120 mg orally or a placebo 1 hr prior to surgery. Patients were observed for postoperative pain, fentanyl consumption, PONV, fatigue and sedation, and respiratory depression. Results were analyzed by the ANOVA, a Chi square test, the Mann Whitney U test and by Fisher's exact test. P values of less than 0.05 were considered to be significant. Results: Postoperative pain and fentanyl consumption were significantly reduced by methylprednisolone, etoricoxib and their combination when compared with placebo (P<0.05). The methylprednisolone + etoricoxib combination caused a significant reduction in postoperative pain and fentanyl consumption as compared to methylprednisolone or etoricoxib alone (P<0.05); however, there was no significant difference between the methylprednisolone and etoricoxib groups (P>0.05). The methylprednisolone and methylprednisolone + etoricoxib combination significantly reduced the incidence and severity of PONV and fatigue as well as the total number of patients requiring an antiemetic treatment compared to the placebo and etoricoxib (P<0.05). Conclusions: A preoperative single-dose administration of a combination of methylprednisolone and etoricoxib reduces postoperative pain along with fentanyl consumption, PONV, antiemetic requirements and fatigue more effectively than methylprednisolone or etoricoxib alone or a placebo.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.45-54
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• 2012

Location-based services with GPS positioning technology as a key technology, but recognizing the current location through satellite communication is not possible in an indoor location-aware technology, low-power short-range communication is primarily made of the study. Especially, as Chirp Spread Spectrum(CSS) based location-aware approach for low-power physical layer IEEE802.15.4a is selected as a standard, Ranging distance estimation techniques and data transfer speed enhancements have been more developed. It is known that the distance measured by CSS ranging has quite a lot of noise as well as its bias. However, the noise problem can be adjusted by modeling the non-zero mean noise value by a scaling factor which corresponds to the change of magnitude of a measured distance vector. In this paper, we propose a localization system using the CSS signal to measure distance for a mobile node taken a measurement of the exact coordinates. By applying the extended kalman filter and least mean squares method, the localization system is faster, more stable. Finally, we evaluate the reliability and accuracy of the proposed algorithm's performance by the experiment for the realization of localization system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5622-5632
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• 2011

This paper presents the simulation design and analysis of Integrated Logistics System(ILS) which is operated by using the AGV(Automated Guided Vehicle). To maximize the operation performances of ILS with AGV, many parameters should be considered such as the number, velocity, and dispatching rule of AGV, part types, scheduling, and buffer sizes. We established the design of experiment in a way of Orthogonal Array in order to consider (1)maximizing the throughput; (2)maximizing the vehicle utilization; (3)minimizing the congestion; and (4)maximizing the Automated Storage and Retrieval System(AS/RS) utilization among various critical factors. Furthermore, we performed the optimization by using the simulation-based analysis and Evolution Strategy(ES). As a result, Orthogonal Array which is conducted far fewer than ES significantly saved not only the time but the same outcome when compared after validation test on the result from the two methods. Therefore, this approach ensures the confidence and provides better process for quick analysis by specifying exact experiment outcome even though it provides small number of experiment.