• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.449-455
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• 2012

During the measurement of the flow rate of gases such as natural gas, flow hunting is observed in most orifice meters but the intensity of flow hunting at each metering system shows different characteristics. In order to investigate why such a difference occurs and whether the difference actually influences metering error, pipeline network analysis on the main factors and characteristics of flow hunting was carried out in a previous study. Following this, in this study, computational fluid dynamics (CFD) analysis was carried out to clarify the relation between flow instability and flow hunting and determine the factors influencing the orifice meter depending on the intensity of upward pressure fluctuation, time interval, and flow rate. Finally, we showed that the pressure hunting rate is a function of the ratio of the pressure difference before and after an orifice meter. On the basis of CFD analysis results, we also presented some major factors and relations influencing flow hunting.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.175-182
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• 2013

Objective : Intracavitary injection of beta-emitting radiation source for control of cystic tumors has been tried with a benefit of localized internal radiation. The authors treated cystic brain tumor patients with Holmium-166-chitosan complex (Ho-166-chico), composed of a beta-emitting radionuclide Holmium-166 and biodegradable chit polymer, and evaluated the safety and effective measurement for response. Methods : Twenty-two patients with recurrent cystic brain tumor and/or located in a deep or eloquent area were enrolled in this pilot study. The cyst volume and wall thickness were determined on CT or MRI to assess radiological response. The activity of Ho-166-chico injected via Ommaya reservoir was prescribed to be 10-25 Gy to the cyst wall in a depth of 4 mm. Results : There was neither complications related to systemic absorption nor leakage of Ho-166-chico in all 22 patients. But, two cases of oculomotor paresis were observed in patients with recurrent craniopharyngioma. Radiological response was seen in 14 of 20 available follow-up images (70%). Seven patients of 'evident' radiological response experienced more than 25% decrease of both cyst volume and wall thickness. Another 7 patients with 'suggestive' response showed decrease of cyst volume without definitive change of the wall thickness or vice versa. All patients with benign tumors or low grade gliomas experienced symptomatic improvement. Conclusion : Ho-166-chico intracavitary radiation therapy for cystic tumor is a safe method of palliation without serious complications. The determination of both minimal effective dosage and time interval of repeated injection through phase 1 trial could improve the results in the future.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.537-537
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• 2013

Cyclotron-accelerated ion beams are used for various researches, such as nuclear physics, nuclear chemistry, biotechnology, and material sciences including radio-isotope production. Recently considerable applications are asked to the cyclotron development undertaken to meet user requirements of various ions'energies, intensities, and their pulsed beams. For instance, a cocktail beam acceleration technique rapidly changing the ion species and energies was developed to irradiating integrated circuit chips. Also a chopping system in a cyclotron injection line is considered for producing a pulsed ion beam with a relatively long period compared with that generated by the resonance frequency. For the research in neutron time-of-flight measurement, a single-pulsed beam with a repetition interval of the order of mili-seconds or longer is necessary to have a good resolution and to remove background events. In this paper a feasibility of pulsed beam with an external ion source is simulated by adopting a combination system of a chopper accompanying with a bunching stage in the injection line and an additional chopper after the exit of the cyclotron in order to produce beam pulses with a range of $1{\mu}s{\sim}1ms$ periods from a resonance RF cycle. The pulseperiod will be adjusted by chopping the number of beam bunches from the injected pulses in the injection line. However, the longer pulses will have reduced number of beam pulses and sacrificed beam currents. Because the beam users need an intense single pulsed beam, a careful tuning of the acceleration phase and a high-intense external ion source are necessary to achieve an intense single-pulsed beam from the cyclotron. It is essential to strictly match the acceleration phase of injected beams in the central region of the cyclotron to improve its efficiency. An effect of space charge at each pulse from the ion source will be also considered.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.112-122
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• 2003

The purpose of this study is to search effect that GCM joint treatment gets to right and left range of motion of neck, lumbar, trunk and anke joint. Estimated body deformity using GCM body type assesment chart then measured range of motion of each region. After control group did as act freely after do experiment premeasurement control group did postmeasurement. Each region was measured by measurer who each subject person differs. Experimental group did GCM joint treatment and all measurements each region by measurer who each subject person differs three times measured. When measure with each measurement, measured after leave and walk time interval for 10 minutes. For the analysis of the resulr of experiment the results is change amount comparison increased to keep in mind except ankle joint's dorsiflexion before experiment of experimental group and control group(P<.05). Before an experiment and after an experiment of experimental group, differed to keep in mind in right and left comparison of neck rotation, dorsiflexion, plantaflexin of ankle joint in change amount comparison(P<.05). Neck lateral flexion appears and displayed significantly level right and left difference than rotation after experiment of experimental group(P<.05). Because dorsiflexion, plantefleaion of ankle joint became similar right and left significantly difference did not appear(P<.05).

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.331-336
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• 2007

Objective : The aim of this study was to analyze the treatment results and prognostic factors in patients with massive cerebral infarction who underwent decompressive craniectomy. Methods : From January 2000 to December 2005, we performed decompressive craniectomy in 24 patients with massive cerebral infarction. We retrospectively reviewed the medical records, radiological findings, initial clinical assessment using the Glasgow Coma Scale, serial computerized tomography (CT) with measurement of midline and septum pellucidum shift, and cerebral infarction territories. Patients were evaluated based on the following factors : the pre- and post-operative midline shifting on CT scan, infarction area or its dominancy, consciousness level, pupillary light reflex and Glasgow Outcome Scale. Results : All 24 patients (11 men, 13 women; mean age, 63 years; right middle cerebral artery (MCA) territory, 17 patients; left MCA territory, 7 patients) were treated with large decompressive craniectomy and duroplasty. The average time interval between the onset of symptoms and surgical decompression was 2.5 days. The mean Glasgow Coma Scale was 12.4 on admission and 8.3 preoperatively. Of the 24 surgically treated patients, the good outcome group (Group 2 : GOS 4-5) comprised 9 cases and the poor outcome group (Group1 : GOS 1-3) comprised 15 cases. Conclusion : We consider decompressive craniectomy for large hemispheric infarction as a life-saving procedure. Good preoperative GCS, late clinical deterioration, small size of the infarction area, absence of anisocoria, and preoperative midline shift less than 11mm were considered to be positive predictors of good outcome. Careful patient selection based on the above-mentioned factors and early operation may improve the functional outcome of surgical management for large hemispheric infarction.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.3
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• pp.455-469
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• 1994

Regular radiographic examination has been considered an essential diagnositic method for osseointegrated dental implantation. This study investigated marginal bone loss through the measurement on periapical radiographs and changes in bone density through digital subtraction image radiographic method around 88 endoseous root-form dental implants in 43 human subjects. Four types of endosseous dental implants were investigated : Standard series, Mini series and Hex-lock system of Steri-Oss Dental implant system, and $Br{\aa}nemark$-type implant from 3i dental implant system, in a 3 month interval for a total period of 12 months. The results were as follows : 1. Rapid bone loss occurred in the first 3 months in all 4 groups, and the bone level stabilized at the first thread of the implant fixtures. Amount of bone loss for 12 months showed correlation with the length of the polished neck portion. 2. Most of the implant systems showed resorption of alveolar bone up to the polished neck portion although a long polished neck could delay the resolution. 3. Alveolar bone loss apical to the polished neck portion stabilized at the first thread of the fixtures with no correlation to either the time of exposure of the polished neck or types of implant systems. 4. No changes in bone density around the implant threads were observed throughout the experimental period. Bone density decreased at the marginal bone, and increased at the newly-formed alveolar crest. These results indicate that most of the alveolar bone loss occur within the first 12 months after installation of endosseous root-form dental implants resulting in the exposure of polished neck portions, and the bone level stabilizes thereafter at the first thread portions of the implant fixtures. The experimental period of 12 months seems insufficient for observing changes in bone density, and a long-term observation should be needed.

• Spatial Information Research
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• v.7 no.1
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• pp.63-79
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• 1999

In this research, the operational principle and the internal algorithm of theodolite measuring systems are studied and coded for a new software, and the feasibility of the laser system for the above mentioned usage is studied by simulation set-up of the system in the laboratory environment, and for the theodolite system modules for the communication between theodolite and computer is implemented, the data collection and storage, the simultaneous photogrammetric ' bundle ' adjustment for the theodolite position and the target points are coded, compiled and tested. for the simulation set-up of the laser system extensive studies on laser sources and laser detectors are performed, the system composition for the system simulation in the laboratory environment is studied and implemented, and the beam fluctuation due to the environmental changes in the course of the laser beam, such as changes in current of wind or in temperature is experimented. According to Experiment on the Source of 17 meters interval and the Detector, Laser beam is almost doesn't depend on air How, but it is effected by variations of temperature and light. Selecting cloudy day and time without change of temperature, it was realized that it is possible to perform deformation measurement more than approximately 2mm precision.precision.

• The Journal of Korean Physical Therapy
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• v.27 no.1
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• pp.38-42
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• 2015

Purpose: Accuracy and variability of movement in daily life require synchronization of muscular activities through a specific chronological order of motor performance, which is controlled by higher neural substrates and/or lower motor centers. We attempted to investigate whether transcranial direct current stimulation (tDCS) over primary sensorimotor areas (SM1) could influence movement variability in healthy subjects, using a tapping task. Methods: Twenty six right-handed healthy subjects with no neurological or psychiatric disorders participated in this study. They were randomly and equally assigned to the real tDCS group or sham control group. Direct current with intensity of 1 mA was delivered over their right SM1 for 15 minutes. For estimation of movement variability before and after tDCS, tapping task was measured, and variability was calculated as standard deviation of the inter-tap interval (SD-ITI). Results: At the baseline test, there was no significant difference in SD-ITI between the two groups. In two-way ANOVA with repeated measurement no significant differences were found in a large main effect of group and interaction effect between two main factors (i.e., group factor and time factor (pre-post test)). However, significant findings were observed in a large main effect of the pre-post test. Conclusion: Our findings showed that the anodal tDCS over SM1 for 15 minutes with intensity of 1 mA could enhance consistency of motor execution in a repetitive-simple tapping task. We suggest that tDCS has potential as an adjuvant brain facilitator for improving rhythm and consistency of movement in healthy individuals.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.239-244
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• 2006

Borehole radar reflection surveys were carried out in the horizontal borehole to detect EDZ while constructing the tunnel for the research facility of the nuclear waste disposal in Korea. The horizontal borehole has been bored at a length of 35 m from shelter to be parallel with the tunnel which would be planed. While the tunnel has been constructing with the explosive excavation, the borehole radar reflection surveys carried out 5 times with the interval of 2 or 4 days for monitoring EDZ. The most typical change of the reflection event resulted from the face of the wall of tunnel which had been produced newly by the excavation of the tunnel daily, EDZ has been detected with constructing images of difference between two measurement stages, and also the change of EDZ through the time has been done, which is due to the generation of crack and weakening of the rock strength of the face of the tunnel's wall near previous portion of the face of a blind end of tunnel according to explosive excavation.

• Journal of Korean society of Dental Hygiene
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• v.16 no.2
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• pp.241-248
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• 2016

Objectives: The purpose of the study is to evaluate the dental website usability in Korea. The dental website included dental university hospital, network dental hospital and dental office. Methods: The study was carried out by three age groups including twenties, thirties, and forties. Each group consisted of ten customers and evaluated twelve websites of dental hospitals. Each was assigned to four hospitals and three tasks including easiness of online reservation, preventive information, and treatment information. They filled out the self-administered questionnaire. The questionnaire included the easiness of on-line reservation, satisfaction on the quality and quantity of preventive informations, satisfaction on the quality and quantity of treatment informations, predictiveness on the sub-menu, usefulness of site map, information on the main page of web site, usefulness of decision on visit to dentistry, and revisit intention. Results: The easiness of on-line reservation was the highest in the private dental office, and university dental hospital and network dental hospitals followed in conducting task(1). The anticipated value and measurement on the usefulness of web site were the lowest in network dental hospitals and the time interval between two values was 57 seconds. This discrepancy showed the largest difference. The satisfaction on treatment information in task(3) was higher than that of the satisfaction on preventive information in task (2). The revisit intention was the highest in dental university hospitals. Conclusions: This study showed the comparison in usefulness of web site of university dental hospitals, network dental hospitals and private dental office. The web site focused on the treatment information rather than preventive information. This study suggested that the most important function of dental web site would be the preventive information that was mainly operated by the role of dental hygienists rather than treatment information in the future.