• Clinical and Experimental Pediatrics
• /
• v.60 no.11
• /
• pp.373-378
• /
• 2017

Purpose: The aim of this study was to investigate the statistical properties of four previously developed pediatric coronary artery z score models in healthy Korean children. Methods: The study subjects were 181 healthy Korean children, whose age ranged from 1 month to 15 years. The diameter of each coronary artery was measured using 2-dimensional echocardiography and converted to the z score in the four models (McCrindle, Olivieri, Dallaire, and Japanese model). Descriptive statistical analyses and 1-sample t tests were performed. Results: All calculated z scores had P values of ${\geq}0.050$ using the Kolmogorov-Smirnov test. The one sample t test showed that the mean z scores did not converge to zero except in 1 model, and the mean right coronary artery (RCA) z score was less than zero in all 4 models. The smaller RCA diameter in this study could be associated with the more distal measuring point used to avoid the conal branch. The percentage of subjects with extreme z score values (${\geq}2.0$ and ${\geq}2.5$) for the left main coronary artery (LMCA) seems to be higher in the Dallaire (4.9% and 3.3%) and Japanese models (7.1% and 3.8%). Conclusion: All 4 models showed statistical feasibility of normal distribution. More precise instructions would be needed for the measurement of the RCA. The higher percentage of extreme z scores for the LMCA is compatible with the basic understanding of anatomic variation in the LMCA.

• The korean journal of orthodontics
• /
• v.50 no.3
• /
• pp.157-169
• /
• 2020

Objective: The aim of this retrospective study was to evaluate the pre- and postsurgical bone densities at alveolar and extra-alveolar sites following two-jaw orthognathic surgery. Methods: The sample consisted of 10 patients (mean age, 23.2 years; range, 18.0-27.8 years; 8 males, 2 females) who underwent two-jaw orthognathic surgery. A three-dimensional imaging program (Invivo 5) was used with multidetector computed tomography images taken pre- and postoperatively (obtained 32.3 ± 6.0 days before surgery and 5.8 ± 2.6 days after surgery, respectively) for the measurement of bone densities at the following sites: (1) alveolar bone in the maxilla and mandible, (2) extra-alveolar sites, such as the top of the head, menton (Me), condyle, and the fourth cervical vertebrae (C4). Results: When pre- and postsurgical bone densities were compared, an overall tendency of decrease in bone density was noted. Statistically significant reductions were observed in the densities of cancellous bone at several areas of the maxillary alveolar bone; cortical and cancellous bone in most areas of the mandibular alveolar bone; cortical bone in Me; and cancellous bone in C4. There was no statistically significant difference in bone density in relation to the depth of the alveolar bone. In a comparison of the bone densities between groups with and without genioplasty, there was almost no statistically significant difference. Conclusions: Accelerated tooth movement following orthognathic surgery may be confirmed with reduced bone density. In addition, this study could offer insights into bone metabolism changes following orthognathic surgery, providing direction for further investigations in this field.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.34 no.6
• /
• pp.955-968
• /
• 2010

Three-dimensional body data has been used in many industry fields including the apparel industry. This research used data from a study of the changes in lower body girth measurements from a 3D scan study of 25 female subjects aged 18 to 24 in four postures; a standing posture, a $120^{\circ}$ knee bend posture, a one pace stepping posture, and a sitting posture with a $90^{\circ}$ knee bend. We used the information on the difference between standing and seated measurements to adjust ease values for pants patterns an evaluation of the appearance, and the comfort of the pants. Waist girth in the sitting posture increased 8% compared to a standing posture and the hip girth measurement increased 7%. A basic pants pattern (pants A) with 2.4cm ease at the waist and 2.6cm ease at the hip was developed and a pants pattern (pants B) was developed using the rates of lower body girth change with a 5.7cm ease (8% change) at the waist and 7cm ease (7% change) at the hip. The appearance assessment items of pants A in a standing posture were higher than pants B. On the other hand, most appearance assessment items of pants B in a sitting posture were higher than pants A, especially the ease of pants back waistline and the appearance of the whole back. Comfort assessment items of pants B in both standing and sitting postures were higher than the comfort assessment items for pants A, especially the location of pants waistline, the ease of pants at the waistline, and the ease at the abdomen. In order to find the best level of ease for better appearance and comfort in both standing and sitting postures, 20 pants were constructed with ease values at the waist and hip in increments of 1.1cm in the range between the ease values of pants A and pants B. A fit test was conducted to compare the average appearance and comfort ratings that identified the pants with the best ease values at the waist and hip. The highest total mean was achieved in the pants with a waist ease of 4.6cm and hip ease of 4.8cm.

• The Journal of Korean Society for Radiation Therapy
• /
• v.18 no.2
• /
• pp.81-87
• /
• 2006

Purpose: Few researches have been peformed on the dose distribution of the moving organ for radiotherapy so far. In order to simulate the organ motion caused by respiratory function, multipurpose phantom and moving device was used and dosimetric measurements for dose distribution of the moving organs were conducted in this study. The purpose of our study was to evaluate how dose distributions are changed due to respiratory motion. Materials and Methods: A multipurpose phantom and a moving device were developed for the measurement of the dose distribution of the moving organ due to respiratory function. Acryl chosen design of the phantom was considered the most obvious choice for phantom material. For construction of the phantom, we used acryl and cork with density of $1.14g/cm^3,\;0.32g/cm^3$ respectively. Acryl and cork slab in the phantom were used to simulate the normal organ and lung respectively. The moving phantom system was composed of moving device, moving control system, and acryl and cork phantom. Gafchromic film and EDR2 film were used to measure dose ditrbutions. The moving device system may be driven by two directional step motors and able to perform 2 dimensional movements (x, z axis), but only 1 dimensional movement(z axis) was used for this study. Results: Larger penumbra was shown in the cork phantom than in the acryl phantom. The dose profile and isodose curve of Gafchromic EBT film were not uniform since the film has small optical density responding to the dose. As the organ motion was increased, the blurrings in penumbra, flatness, and symmetry were increased. Most of measurements of dose distrbutions, Gafchromic EBT film has poor flatness and symmetry than EDR2 film, but both penumbra distributions were more or less comparable. Conclusion: The Gafchromic EBT film is more useful as it does not need development and more radiation dose could be exposed than EDR2 film without losing film characteristics. But as response of the optical density of Gafchromic EBT film to dose is low, beam profiles have more fluctuation at Gafchromic EBT. If the multipurpose phantom and moving device are used for treatment Q.A, and its corrections are made, treatment quality should be improved for the moving organs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.61-70
• /
• 2004

This paper treats optimal route assessment system at seaway based on weather forecasting and wave measurement through observation. Since early times. captain & officer have been sailing to select the optimum route considering the weather ana ship status condition empirically. However. it is rare to find digitalized onboard route support system whereas weather fax or wave and swell chart are utilized for the officer. based on officer's experience. In this paper, optimal route assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA (estimated time of arrival) ana fuel consumption is evaluated for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method. Basically. the weather forecast is assumed to be prepared previously in order to operate this system.

• Journal of the Korean Society of Radiology
• /
• v.7 no.1
• /
• pp.45-50
• /
• 2013

Non-invasive technique CT, called automated computed tomography, is used to detect lesion of a patient when diagnosing human body. Information obtained from CT plays an important role in assembling 3 dimensional images. Recently, new equipment, operated by CT, is required which can be appliable to physical and biological research. In accordance to this quest, micro-CT is invented that produce more detail and concrete information. Images supplied by CT are even more detailed and concrete, so it contributes much to the development of biology and polymer material engineering field. However, there has been little reliable reports regarding measuring information of space dose distribution about exposure dose limit of users operating micro-CT. In addition, little reports regarding space dose distribution of exposure has been known about unwanted diffraction light produced by usage of micro-CT. The exterior of micro-CT is covered by lead, which is for removing exposure of diffraction light. Thus, even if it is good enough to prevent exposure of diffraction light, consistent management of equipment will be required as time goes by and equipment are getting old as well. We measured space dose distribution regarding exposure of diffraction light of users operating micro-CT directly. Therefore, we suggest that proper management should be necessary for users operating micro-CT not to be exposed by unwanted diffraction light.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.47 no.2
• /
• pp.176-187
• /
• 2020

The purpose of this study is to evaluate validity, reliability and reproducibility of tooth width (TW), arch length (AL) and arch length discrepancy (ALD) measured on a digital model taken via 3-dimensional model scanner and intraoral scanner compared to a plaster model. A total of 30 patients aged 12 to 18 were eligible for the study. 3 types of models were acquired from each patient: a conventional plaster model (P), a model scanned digital model (MSD) taken via Freedom UHD^® and an intraoral scanned digital model (ISD) taken via CS3600^® in-vivo. The reliability of TW and AL in each group was evaluated using Pearson's correlation coefficient, while the reproducibility was evaluated with intraclass correlation coefficient. The validity of space analysis was assessed by paired t-test. As a result, all measurements of P, MSD and ISD groups showed favorable reliability and reproducibility. Most of measurements for space analysis in MSD group and TW in ISD group also presented high validity. AL and ALD presented statistically significant difference between P and ISD group. The validity of measurements of space analysis in ISD group was short in doubt to valid, but clinically acceptable. Both MSD and ISD are clinically acceptable to use for space analysis but clinician should be aware that errors can be found using a digital model.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.39 no.3
• /
• pp.218-229
• /
• 2003

A new biotelemetry method that the installation and the treatment of equipment is convenient and the instantaneously detailed location of the fish attached the pinger is able to track comparatively easily was developed. The receiving system in this biotelemetry method was advanced for track the detailed behavior of the fish by the miniature tracking pinger, because it was a burden to fish to add the pinger with the water temperature and the pressure sensor. By combining of the super short base line (SSBL) method to detect the direction of pinger and the pinger synchronizing method to measure the range from receiving transducer to pinger, the three dimensional locations of fish to the receiving transducer is gotten instantaneously. The receiving system is devised to realize the high precision or wide detection range by application of the basic design method for receiving system of biotelemetry developed by the present authors and the hydrophone array configuration. The measurement distance error in the pinger synchronizing method is minimized through the correction of which the deviation of transmission pluse period of pinger is caused by changing water temperature. A prototype system which is able to track the instantaneously detailed location of the fish by the SSBL and pinger synchronizing biotelemetry (SPB) method was produced.

• International Journal of Highway Engineering
• /
• v.13 no.2
• /
• pp.67-75
• /
• 2011

Domestic economic development, industrialization, and urbanization have brought along not only increased highway traffic but also elevated traffic noise levels. Thus, it is necessary to accurately predict the traffic noise levels in order to address the public demand of alleviating the noise levels in urban areas. In this study, the method of evaluating the sound power level of road traffic was investigated in terms of considering the types of road surface and vehicle, based on previous researches. Regarding CPX (Close Proximity Test) and Pass-by test, the measured noise data of Test Road of Korea Highway Corporation were utilized in order to construct the database of sound power levels of various vehicles. Specifically, the 38 noise measurement and analysis in 1/1-octave band frequencies at 12 pre-selected sites were carried out, considering topography and road surface. Finally, the comparison study was conducted between predicted and measured data in terms of traffic noise. The traffic noise prediction was based on the KRON (Korea Road Noise) program, which was developed being equipped wit 3-dimensional GUI. In addition, the traffic noise characteristics were evaluated in terms of vehicle types and pavement surface conditions.

• Journal of the Korean Vacuum Society
• /
• v.22 no.3
• /
• pp.156-161
• /
• 2013

We fabricated transparent conductive electrodes with silver (Ag) nanofibers by electrospinning process. Ag nanofibers have high aspect ratio and fused junctions which result in low sheet resistance. Electrospinning is a fast and efficient process to fabricate continuous one-dimensional (1D) nanofibers. Ag/polymer ink were prepared in polymer matrix solution by a sol-gel method. Then, Ag/polymer nanofibers precursors are heated at $200{\sim}500^{\circ}C$ in air for 2 h to eliminate partially the polymers. The topographical features of the Ag nanofibers were characterized by FE-SEM, and the electrical property was analyzed through I-V measurement system. Finally, optical property was measured using UV/VIS spectroscopy. The transparent conductive electrodes with Ag nanofibers exhibited a sheet resistance (Rs) of $250{\Omega}/sq$ at a transparency (T) of 83%. Transparent conductive films, contain the Ag nanofibers as conductive materials, have good electrical, optical, and mechanical properties. Therefore, it is expected to be useful for the application of flexible display in the future.