• The Journal of Korea Robotics Society
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• v.7 no.2
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• pp.120-128
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• 2012

The loop closure problem is one of the most challenging issues in the vision-based simultaneous localization and mapping community. It requires the robot to recognize a previously visited place from current camera measurements. While the loop closure often relies on visual bag-of-words based on point features in the previous works, however, in this paper we propose a line-based method to solve the loop closure in the corridor environments. We used both the floor line and the anchored vanishing point as the loop closing feature, and a two-step loop closure algorithm was devised to detect a known place and perform the global pose correction. We propose an anchored vanishing point as a novel loop closure feature, as it includes position information and represents the vanishing points in bi-direction. In our system, the accumulated heading error is reduced using an observation of a previously registered anchored vanishing points firstly, and the observation of known floor lines allows for further pose correction. Experimental results show that our method is very efficient in a structured indoor environment as a suitable loop closure solution.

• Journal of the Speleological Society of Korea
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• no.82
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• pp.17-25
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• 2007

The use of a low-frequency cave radio can also verify survey accuracy. A receiving unit on the surface can pinpoint the depth and location of a transmitter in a cave passage by measurement of the geometry of its radio waves. A survey over the surface from the receiver back to the cave entrance forms an artificial loop with the underground survey, whose loop-closure error can then be determined. In the past, caves were reluctant to redraw complex cave maps after detecting survey errors. Today, computer cartography can automatically redraw cave maps after data has been corrected.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.5
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• pp.225-230
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• 2015

In this paper, we propose an effective real-time visual loop closure detector, VILODE, which makes use of key frames and bag of visual words (BoW) based on SURF feature points. In order to determine whether the camera has re-visited one of the previously visited places, a loop closure detector has to compare an incoming new image with all previous images collected at every visited place. As the camera passes through new places or locations, the amount of images to be compared continues growing. For this reason, it is difficult for a visual loop closure detector to meet both real-time constraint and high detection accuracy. To address the problem, the proposed system adopts an effective key frame selection strategy which selects and compares only distinct meaningful ones from continuously incoming images during navigation, and so it can reduce greatly image comparisons for loop detection. Moreover, in order to improve detection accuracy and efficiency, the system represents each key frame image as a bag of visual words, and maintains indexes for them using DBoW database system. The experiments with TUM benchmark datasets demonstrates high performance of the proposed visual loop closure detector.

• 대한치과교정학회:학술대회논문집
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• 1997.11a
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• pp.51.1-51.1
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• 1997

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.770-774
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• 2012

Protein loops are often involved in diverse biological functions, and some functional loops show conformational changes upon ligand binding. Since this conformational change is directly related to ligand binding pose and protein function, there have been numerous attempts to predict this change accurately. In this study, we show that it is plausible to obtain meaningful ensembles of loop conformations for flexible, ligand-binding protein loops efficiently by applying a loop modeling method. The loop modeling method employs triaxial loop closure algorithm for trial conformation generation and conformational space annealing for global energy optimization. When loop modeling was performed on the framework of ligand-free structure, loop structures within $3\AA$ RMSD from the crystal loop structure for the ligand-bound state were sampled in 4 out of 6 cases. This result is encouraging considering that no information on the ligand-bound state was used during the loop modeling process. We therefore expect that the present loop modeling method will be useful for future developments of flexible protein-ligand docking methods.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.33-45
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• 2004

The purpose of this experimental study was to determine appropriate magnitude of the Gable bends to produce maximum retraction of the anterior teeth. The Calorific Machine was used to illustrate the tooth movement in three dimension. The experimental teeth except the first premolar were embedded in the artificial alveolar bone part. In a series of experiments, the extraction space was closed using arch wires with bull loops into which the gable bends of $10^{\circ},\;20^{\circ},\;30^{\circ}$ degrees were incorporated. The experiments were repeated three times for each degree of the gable bend. Before and after the space closure, radiographs were taken in the sagittal and occlusal directions using occlusal films. Analysis of variance and Scheffe post hoc test were used to determine significant differences among the three groups. The following results were obtained. 1. As magnitudes of the gable bends increased, more bodily anterior tooth movement was seen and the distance of retraction also increased. 2. As magnitudes of the gable bends increase, the amount of posterior tooth protraction decreased while intrusive and buccal movement increased. 3. The arch was coordinated by distal-in rotation of the canine and mesial-in rotation of the second premolar adjacent to the extraction space.

• Advances in pediatric surgery
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• v.15 no.1
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• pp.18-26
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• 2009

The survival of Very Low Birth Weight (VLBW) infants has been improved with the advancement of neonatal intensive care. However, the incidence of accompanying gastrointestinal complications such as necrotizing enterocolitis has also been increasing. In intestinal perforation of the newborn, enterostomy with or without intestinal resection is a common practice, but there is no clear indication when to close the enterostomy. To determine the proper timing of enterostomy closure, the medical records of 12 VLBW infants who underwent enterostomy due to intestinal perforation between Jan. 2004 and Jul. 2007 were reviewed retrospectively. Enterostomy was closed when patients were weaned from ventilator, incubator-out and gaining adequate body weight. Pre-operative distal loop contrast radiographs were obtained to confirm the distal passage and complete removal of the contrast media within 24-hours. Until patients reached oral intake, all patients received central-alimentation. The mean gestational age of patients was $26^{+2}$ wks ($24^{+1}{\sim}33^{+0}$ wks) and the mean birth weight was 827 g (490~1450 g). The mean age and the mean body weight at the time of enterostomy formation were 15days (6~38 days) and 888 g (590~1870 g). The mean body weight gain was 18 g/day (14~25 g/day) with enterostomy. Enterostomy closure was performed on the average of 90days (30~123 days) after enterostomy formation. The mean age and the mean body weight were 105 days (43~136 days) and 2487 g (2290~2970 g) at the time of enterostomy closure. The mean body weight gain was 22 g/day after enterostomy closure. Major complications were not observed. In conclusion, the growth in VLBW infants having enterostomy was possible while supporting nutrition with central-alimentation and the enterostomy can be closed safely when the patient's body weights is more than 2.3 kg.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.297-303
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• 1998

The sinus distal to the prosthetic heart valve influences the valve closure behavior and velocity field near the valve, therefore affects the hydrodynamic performance of the prosthetic heart valve. In order to study the effects of valve distal geometry on the hydrodynamic performance of the prosthetic valves, mechanical bileaflet valve(SJMV), monoleaflet polymer valve(MLPV) and trileaflet polymer valve(FTPV) are inserted in the test sections which have the straight and the sinus shape distal to the valve. Leakage volumes and systolic mean pressure drops are measured in the pulsatile mock circulation flow loop. Leakage volumes are slightly less and systolic mean pressure drops are higher in the sinus test section comparing to those in the straight test section, but the differences are statistically insignificant. Flow waveforms are analyzed in order to predict the valve closure behavior. The distal sinus does not affect the closure of the MLPV, but early valve closure of SJMV is observed in the sinus test section. This effect is more significant in FTPV, and the reverse flow peak of FTPV is reduced in the sinus test section. Therefore the sinus distal to the valve can reduce the reverse flow jet caused by sudden valve closure.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.371-380
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• 2005

The purpose of this experimental study was to evaluate aㅜd compare maxillary arch dimensional and positional changes between first and second premolar extraction groups. The Calorific Machine was used to illustrate tooth movement in three dimensions. The experimental teeth except the first or second premolars were embedded in artifical alveolar bone. The extraction space was closed using arch wires with bull loops into which 15 degree gable bends were placed. Before and after space closure, radiographs were taken in the sagittal and occlusal directions using occlusal films. The results showed greater mean maxillary incisor retraction and less anchorage loss in the maxillary first premolar extraction group than in the maxillary second premolar extraction group. Mesiopalatal rotation of anchor teeth was greater after extraction of a maxillary second premolar than a maxillary first premolar (P<.001).

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.5
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• pp.819-830
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• 2010

This study proposes medical gowns for interns and residents that address the functions of utility and activity. Based on the questionnaires, the prototype focused on the pockets for practical use and movement adaptability. Functional pockets were made by increasing pocket sizes and separating pockets with sections according to use. An inside pocket and a loop for an identification tag was placed on the chest pocket and the side seam pocket were oblique lined. To resolve horizontal stress on the back of the gown,6 cm action pleats were added at both ends of the bladebone. The elbow area was tucked up to improve the workplace activities. To reduce hamper on the gown hemline, slits were added along the gown side seam. The front button was changed into an inside button closure. The cuffs, belt, and back waist belt were removed due to occupational cases of inconvenience. The length of the sleeves was adjusted with belts to improve the movement of the arms. In accordance with design preference, the gown was designed to be knee-length with wrist length sleeves. Blue colored (2.5PB 3/12: by Munsell) material was inserted to reduce the contamination on the neck, cuffs, front closure, and hemline area. The planning cloth of the experimental gown was designed to improve activity function, cleaning, and comfort from light materials. The field test (with 30 doctors at university hospitals and the objective assessment with 9 subject groups)were done by the valuation between the existing gown and the prototype. The results showed that the prototype had to be modified by decreasing the pocket size, expanding the usage of the penholder, and simplify front pockets in order to maintain unity. The loop for the identification tag, inside pocket, and the blue colored material had to be removed. The front closure of the gown had to return to its original state.