• The Korean Journal of Nuclear Medicine
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• v.23 no.2
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• pp.175-181
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• 1989

Visual assessment of regional wall motion abnormality (RWMA) by gated blood pol scan (GBPS) serves as an useful parameter in the diagnosis, functional evaluation, and follow up in various clinical settings, but are still subject to some inherent limitations. On important problem may be the interobserver as well as intraobsever variation that may well be present due to the subjective nature of the interpretations. This study was carried out to determine the reliability and reproducibility of visual assessments made in GBPSs, and to observe the degree to which the results would be influenced by observer variation. Fifty two patients with coronary heart disease had resting GBPS and contrast ventriculography within 4 days appall. Contrast ventriculography-showed normal wall motion in 6 patients and the remaining 46 had RWMA in one or more segments. The anterior and left anterolateral views of all 52 GBPSs were analyzed by three independent observers, who selected from 5 scales, their level of confidence that there was RWMA in that segment. Reciever operating characteristic (ROC) curves for each analysis was plotted and the area under the curve $(\theta)$ was used as a parameter representing each observer's performance in his interpretations. The findings of contrast ventriculographies were used as the standard for RWMA. The apical and inferoapical segments showed the best correlation with contrast ventriculography ($\theta=0.90-0.94$, 0.81-0.94, respectively), and the inferior wall showed the poorest correlation $(\theta=0.70-0.74)$. The interpretations of the inferior, septal, apical, and posteroinferior, segments showed no difference between the observers, but there was significantly better performance in assessment by observer A compared to that by B or C for the anterolateral segments ($\theta=0.87$, 0.78, 0.76, respectively. p<0.01 for A vs B, p<0.05 for A vs C), as well as when all segments were considered altogether ($\theta=0.88$, 0.83, 0.82, respectively. both p<0.05). This was also true for the infero-apical segment between A and C ($\theta=0.09$, 0.81, p<0.05). The intraobserver variation, however, did not appear significant, with only the inferior segment for observer B showing any significant difference when observer A and B repeated the analysis 10 days latter. There was no difference in assessing dyskinesia, with all observers showing a high performance ($\theta=0.98$, 0.87, 0.97, respectively). The visual assessment of left ventricular ejection fraction by all three observers correlated well with the calculated value from a semiautomated method (Spearman's r = 0.91, 0.83, 0.83. p<0.01, p<0.05, p < 0.05). The assessment of LV and RV size also correlated well between the three observers (Kendall's w = 0.80, 0.51, p<0.01 for both left and right ventricles). The above findings suggest that RWMA visually assessed by GBPS correlates well with that done by contrast ventriculography. And although the observer's experience or skill may influence the results in certain segments, visual analysis of GBPS may serve as a reliable and reproducible means for evaluating ventricular function.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.203-218
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• 2010

The site categorization and corresponding site amplification factors in the current Korean seismic design guideline are based on provisions for the western United States (US), although the site effects resulting in the amplification of earthquake ground motions are directly dependent on the regional and local site characteristic conditions. In these seismic codes, two amplification factors called site coefficients, $F_a$ and $F_v$, for the short-period band and midperiod band, respectively, are listed according to a criterion, mean shear wave velocity ($V_S$) to a depth of 30 m, into five classes composed of A to E. To suggest a site classification system reflecting Korean site conditions, in this study, systematic site characterization was carried out at four regional areas, Gyeongju, Hongsung, Haemi and Sacheon, to obtain the $V_S$ profiles from surface to bedrock in field and the non-linear soil properties in laboratory. The soil deposits in Korea, which were shallower and stiffer than those in the western US, were examined, and thus the site period in Korea was distributed in the low and narrow band comparing with those in western US. Based on the geotechnical characteristic properties obtained in the field and laboratory, various site-specific seismic response analyses were conducted for total 75 sites by adopting both equivalent-linear and non-linear methods. The analysis results showed that the site coefficients specified in the current Korean provision underestimate the ground motion in the short-period range and overestimate in the mid-period range. These differences can be explained by the differences in the local site characteristics including the depth to bedrock between Korea and western US. Based on the analysis results in this study and the prior research results for the Korean peninsula, new site classification system was developed by introducing the site period as representative criterion and the mean $V_S$ to a depth of shallower than 30 m as additional criterion, to reliably determine the ground motions and the corresponding design spectra taking into account the regional site characteristics in Korea.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.327-348
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• 2004

In this study, after analyzing several local climate characteristics of South Korea, I validated distribution, invasion, foraging, underground activities, attack season as ecological characteristics and also temperature, relative humidity, and tree species as preference characteristics of Korean termites (Reticulitermes speratus kyushuensis Morimoto). Especially, southern part of the Korean peninsula is a suitable area for inhabitation and motion of termites holding same ecological characteristic like R. speratus kyushuensis. Busan is a neighboring district at field distribution north limiting temperature of Coptotermes formosanus Shiraki and Chuncheon is a passing area through the Korean Peninsula of field distribution north limiting temperature of Reticulitermes speratus Kolbe. The termite attack of wood devices was about 34.5% for 3 years in the forest of Jongmyo. Although the attack rate of termite increased each year, the detection rate decreased and the missing rate was high by degrees. I confirmed a foraging habits which is a part of termite colony was a role of continuous decomposition and another was a role of new food hunt as experimental results. The foraging termites were found under ground at Jongmyo in Seoul from April to November in the 2001 and the most active period was on July and August. The termite invasion rate of bait station increased in every monitoring. Through the increasing attack rate of bait station during 2nd monitoring (November, 2000) and 3rd monitoring(March, 2001), I confirmed that termites moved into the deep underground in winter, and were working continuously to forage. R. speratus kyushuensis inhabiting at the Korean Peninsula is a species which has food consumption rate with higher temperature. The termite revealed the greatest amount of food(filter paper) at $30^{\circ}C$(90% RH), but showed increasing death rate at over $32^{\circ}C$. Also, survival rate of this termite was 97% at 84% RH($30^{\circ}C$), but killed 100% at 52% RH($30^{\circ}C$) and 70% RH($30^{\circ}C$). For wood feeding, this was observed the preference in a pine tree(Pinus densiflora) above all others. Survival of termites was high(87%) at a pine tree, but low(13.5%) at a paulownia tree(Paulownia coreana). In this study, I presented the biological characteristic of termite(R. speratus kyushuensis Morimoto) and confirmed the deterioration degree of termite on wooden cultural heritage in Korea. Depending on climate and soil temperature, each area in the southern part of the Korea Peninsula, has some different active period and different distribution of R. speratus kyushensis. With these results, I expect that this report helps to prepare the integrated pest management(IPM) of the termite on wooden cultural heritage in Korea, and it may help to reduce the economical loss from termite damage in Korea.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.219-228
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• 2003

Purpose: The amount of salvaged myocardium is an important prognostic factor in patients with acute myocardial infarction (MI). We investigated if early Tl-201 SPECT imaging could be used to predict the salvaged myocardium and functional recovery in acute MI after primary PTCA. Materials and Methods: In 36 patients with first acute MI treated with primary PTCA, serial echocardiography and Tl-201 SPECT imaging ($5.8{\pm}2.1$ days after PTDA) were performed. Regional wall motion and perfusion were quantified with on 16-segment myocardial model with 5-point and 4-point scaling system, respectively. Results: Wall motion was improved in 78 of the 212 dyssynergic segments on 1 month follow-up echocardiography and 97 on 7 months follow-up echocardiography, which were proved to be salvaged myocardium. The areas under receiver operating characteristic curves of Tl-201 perfusion score for detecting salvaged myocardial segments were 0.79 for 1 month follow-up and 0.83 for 7 months follow-up. The sensitivity and specificity of Tl-201 redistribution images with optimum cutoff of 40% of peak thallium activity for detecting salvaged myocardium were 84.6% and 55.2% for 1 month follow-up, and 87.6% and 64.3% for 7 months follow-up, respectively. There was a linear relationship between the percentage of peak thallium activity on early redistribution imaging and the likelihood of segmental functional improvement 7 months after reperfusion. Conclusion: Tl-201 myocardial perfusion SPECT imaging performed early within 10 days after reperfusion can be used to predict the salvaged myocardium and functional recovery with high sensitivity during the 7 months following primary PTCA in patients with acute MI.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.225-232
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• 2004

Purpose : Transient wall motion abnormality and contractile dysfunction of the left ventricle (LV) can be observed in patients with coronary artery disease due to post-stress myocardial stunning. To understand clinical characteristics of stress induced LV dysfunction, we have compared the findings of exercise stress test, myocardial perfusion SPECT and coronary angiography between subjects with and without post-stress LV dysfunction. Materials and Methods : Among subjects who underwent exercise stress test, myocardial perfusion SPECT and coronary angiography within a month of interval, we enrolled 36 patients with post-stress LV election fraction (LVEF) was $\geq5%$ lower than rest (stunning group) and 16 patients with difference of post-stress and rest LVEF was lesser than 1 %(non-stunning group) for this study. Treadmill exercise stress gated myocardial perfusion SPECT was performed with dual head SPECT camera using 740 MBq Tc-99m MIBI and coronary angiography was also performed by conventional Judkins method. Results : Stunning group had a significantly higher incidence of hypercholesterolemia than non-stunning group(45.5 vs. 7.1%, p=0.01). Stunning group also had higher incidence of diabetes mellitus and lower incidence of hypertension, but these were not statistically significant. Stunning group had larger and more severe perfusion defect in stress perfusion myocardial SPECT than non-stunning group(extent 18.2 vs. 9.2%, p=0.029; severity 13.5 vs. 6.9, p=0.040). Stunning group also had higher degree of reversibility of perfusion defect, higher incidence of positive exercise stress test and higher incidence of having severe stenosis ($80{\sim}99%$) in coronary angiography than non-stunning group, but these were not statistically significant. In stunning group, all of 4 patients without perfusion defect had significant coronary artery stenosis and had received revascularization treatment. Conclusion : Patients with post-stress LV dysfunction had larger and more severe perfusion defect and severe coronary artery stenosis than patients without post-stress LV dysfunction. All of the patients without perfusion defect in stunning group had significant coronary artery stenosis and needed revascularization. Therefore, we suggest that invasive diagnostic procedures and therapeutic interventions might be needed in patients with post-stress LV dysfunction.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.62-79
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• 2020

The rock-carved seated Avalokiteśvara statue at Ganghwa Bomunsa Temple is a giant rock-carved Buddhist statue that was built in 1928 during the Japanese colonial era. Although it is a year-recorded Buddhist statue that occupies a prominent place in modern Korean Buddhist sculpture history, it has not been the subject of in-depth discussion due to weak research on modern Buddhist sculptures. In this study, to examine the various significant aspects of the rock-carved Seated Avalokiteśvara statue at Bomunsa Temple as a modern Buddhist sculpture, I have managed to determine its construction year, artificers, and patrons by deciphering the inscription around the rock-carved statue; in addition I have researched the effects of the rock shapes and landforms on the formation of the Buddhist statue by comparing and analyzing the points of view of both artificers and worshipers. I have also identified the specific circumstances of the time of construction from interviews with the descendants of artificers. A monk from Geumgangsan Mountain, Lee Hwaeung, took the role of sponsor and chief painter to construct the rock-carved seated Avalokiteśvara statue at Bomunsa temple. In the beginning of its construction in 1928, more than 100 donators jointly sponsored the construction of the statue. Gansong Jeon Hyoungphil sponsored alone at the time of the place of worship's expansion in 1938. Bomunsa Temple has been regarded as one of the top-three sacred places of Avalokiteśvara Bodhisattva together with Naksansa Temple in Yang Yang and Boriam in Nam Hae, due to the construction of the rock-carved statue. It took about three months to construct the statue. Lee Hwaeung drew a rough sketch and then Un Songhag and five masons from Ganghwa Island took part in the carving process. We can observe the line drawing technique around the rock-carved statue because the statue was carved based on the rough sketch of the monk painter. The aspect of Lee Hwaeung as a painter is revealed; therefore, we can identify the clue of painting pattern leading to Seogongchulyou- Hwaunghyoungjin- Ilonghyegag. The rock-carved seated Avalokiteśvara statue at Bomunsa Temple is a typical Avalokiteśvara that wears a jeweled crown and holds Kundica. It makes a strong impression as it has a big square-shaped face and a short neck and is unsophisticated in general. The artificers solved the issue of visual distortion of the rock-carved statue caused by carving on a 10-meter high and 40-degree sloping rock by controlling motion to its maximum, omitting detailed expression by emphasizing symmetry, and adjusting the head-to-body proportion to be almost one-to-one. In this study, especially, I presume the unified form of sacred sculptures and Buddhist altars, without making a Buddhist altar like the rock-carved seated Avalokiteśvara statue at Bomunsa Temple, to be a key characteristic of modern Buddhist sculptures. Furthermore, I make newly clear that the six letters of Sanskrit carved on nimbus, which had been interpreted as a Six-Syllable Mantra, are a combination with Jeongbeopgye and Sabang Mantras. In addition, three iron rings driven on eaves rock were used as a reference point, and after construction they were used as a decoration for the Bodhisattva with hanging wind chimes.

• Journal of Elementary Mathematics Education in Korea
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• v.9 no.2
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• pp.85-110
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• 2005

The purpose of this study is to examine the characteristics of visual representation used in problem solving process and examine the representation types the students used to successfully solve the problem and focus on systematizing the visual representation method using the condition students suggest in the problems. To achieve the goal of this study, following questions have been raised. (1) what characteristic does the representation the elementary school students used in the process of solving a math problem possess? (2) what types of representation did students use in order to successfully solve elementary math problem? 240 4th graders attending J Elementary School located in Seoul participated in this study. Qualitative methodology was used for data analysis, and the analysis suggested representation method the students use in problem solving process and then suggested the representation that can successfully solve five different problems. The results of the study as follow. First, the students are not familiar with representing with various methods in the problem solving process. Students tend to solve the problem using equations rather than drawing a diagram when they can not find a word that gives a hint to draw a diagram. The method students used to restate the problem was mostly rewriting the problem, and they could not utilize a table that is essential in solving the problem. Thus, various errors were found. Students did not simplify the complicated problem to find the pattern to solve the problem. Second, the image and strategy created as the problem was read and the affected greatly in solving the problem. The first image created as the problem was read made students to draw different diagram and make them choose different strategies. The study showed the importance of first image by most of the students who do not pass the trial and error step and use the strategy they chose first. Third, the students who successfully solved the problems do not solely depend on the equation but put them in the form which information are decoded. They do not write difficult equation that they can not solve, but put them into a simplified equation that know to solve the problem. On fraction problems, they draw a diagram to solve the problem without calculation, Fourth, the students who. successfully solved the problem drew clear diagram that can be understood with intuition. By representing visually, unnecessary information were omitted and used simple image were drawn using symbol or lines, and to clarify the relationship between the information, numeric explanation was added. In addition, they restricted use of complicated motion line and dividing line, proper noun in the word problems were not changed into abbreviation or symbols to clearly restate the problem. Adding additional information was useful source in solving the problem.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.230-238
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• 2018

Purpose: Metacarpal fractures are common injuries of the hand. They are treated using closed reduction (CR) or open reduction (OR) techniques. The management strategy depends on fracture site characteristic and fixation methods. In this study, we evaluated pre- and postoperative fracture angulation, when metacarpal fractures bad been treated using two different techniques: CR with parallel transverse pinning and OR with plate fixation. Methods: Forty-six patients undergoing anatomic reduction to treat extra-articular metacarpal fractures were recruited. They were included in one of two therapeutic groups: Group 1, CR with parallel transverse pinning (n=21); Group 2, OR with plate fixation (n=25). Fracture angulation values have been measured on pre- and postoperative radiologic images. Values were compared between pre- and postoperative states, and between corresponding measurements of each group. Results: All extra-articular metacarpal fractures were successfully treated without wound related complications or the limit of joint motion. Both groups demonstrated adequate reduction at immediate postoperative period (postoperative angulation of group 1, $20^{\circ}{\pm}7^{\circ}$; group 2, $19^{\circ}{\pm}5^{\circ}$). During the observation at follow-up period, Group 1 exhibited slight recurrence (follow-up angulation of group 1, $24^{\circ}{\pm}10^{\circ}$). Nonetheless, Group 2 showed adequate reduction state in both immediate postoperative and long-term follow-up periods (follow-up angulation of group 2, $18^{\circ}{\pm}6^{\circ}$). Conclusion: Extra-articular metacarpal fractures were successfully restored without functional complications. CR with parallel transverse pinning method exhibited recurrence after pin removal, which necessitates cautious postoperative exercise and monitoring.

• Journal of Intelligence and Information Systems
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• v.22 no.3
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• pp.165-183
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• 2016

Over the past decade, there has been a rapid diffusion of technological devices and a rising number of various devices, resulting in an escalation of virtual reality technology. Technological market has rapidly been changed from smartphone to wearable devices based on virtual reality. Virtual reality can make users feel real situation through sensing interaction, voice, motion capture and so on. Facebook.com, Google, Samsung, LG, Sony and so on have investigated developing platform of virtual reality. the pricing of virtual reality devices also had decreased into 30% from their launched period. Thus market infrastructure in virtual reality have rapidly been developed to crease marketplace. However, most consumers recognize that virtual reality is not ease to purchase or use. That could not lead consumers to positive attitude for devices and purchase the related devices in the early market. Through previous studies related to virtual reality, there are few studies focusing on why the devices for virtual reality stayed in early stage in adoption & diffusion context in the market. Almost previous studies considered the reasons of hard adoption for innovative products in the viewpoints of Typology of Innovation Resistance, MIR(Management of Innovation Resistant), UTAUT & UTAUT2. However, product-based antecedents also important to increase user intention to purchase and use products in the technological market. In this study, we focus on user acceptance and resistance for increasing purchase and usage promotions of wearable devices related to virtual reality based on headgear products like Galaxy Gear. Especially, we added a variables like attitude confidence as a dimension for user resistance. The research questions of this study are follows. First, how attitude confidence and innovativeness resistance affect user intention to use? Second, What factors related to content and brand contexts can affect user intention to use? This research collected data from the participants who have experiences using virtual rality headgears aged between 20s to 50s located in South Korea. In order to collect data, this study used a pilot test and through making face-to-face interviews on three specialists, face validity and content validity were evaluated for the questionnaire validity. Cleansing the data, we dropped some outliers and data of irrelevant papers. Totally, 156 responses were used for testing the suggested hypotheses. Through collecting data, demographics and the relationships among variables were analyzed through conducting structural equation modeling by PLS. The data showed that the sex of respondents who have experience using social commerce sites (male=86(55.1%), female=70(44.9%). The ages of respondents are mostly from 20s (74.4%) to 30s (16.7%). 126 respondents (80.8%) have used virtual reality devices. The results of our model estimation are as follows. With the exception of Hypothesis 1 and 7, which deals with the two relationships between brand awareness to attitude confidence, and quality of content to perceived enjoyment, all of our hypotheses were supported. In compliance with our hypotheses, perceived ease of use (H2) and use innovativeness (H3) were supported with its positively influence for the attitude confidence. This finding indicates that the more ease of use and innovativeness for devices increased, the more users' attitude confidence increased. Perceived price (H4), enjoyment (H5), Quantity of contents (H6) significantly increase user resistance. However, perceived price positively affect user innovativeness resistance meanwhile perceived enjoyment and quantity of contents negatively affect user innovativeness resistance. In addition, aesthetic exterior (H6) was also positively associated with perceived price (p<0.01). Also projection quality (H8) can increase perceived enjoyment (p<0.05). Finally, attitude confidence (H10) increased user intention to use virtual reality devices. however user resistance (H11) negatively affect user intention to use virtual reality devices. The findings of this study show that attitude confidence and user innovativeness resistance differently influence customer intention for using virtual reality devices. There are two distinct characteristic of attitude confidence: perceived ease of use and user innovativeness. This study identified the antecedents of different roles of perceived price (aesthetic exterior) and perceived enjoyment (quality of contents & projection quality). The findings indicated that brand awareness and quality of contents for virtual reality is not formed within virtual reality market yet. Therefore, firms should developed brand awareness for their product in the virtual market to increase market share.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.45-52
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• 2015

Purpose : The dose distribution of organ at risk (OAR) and normal tissue is affected by treatment technique in postoperative radiation therapy for prostate cancer. The aim of this study was to compare dose distribution characteristic and to evaluate treatment efficiency by devising VMAT plans according to applying differed number of arc and IMRT plan for postoperative patient of prostate cancer radiation therapy using a rectal balloon. Materials and Methods : Ten patients who received postoperative prostate radiation therapy in our hospital were compared. CT images of patients who inserted rectal balloon were acquired with 3 mm thickness and 10 MV energy of HD120MLC equipped Truebeam STx (Varian, Palo Alto, USA) was applied by using Eclipse (Version 11.0, Varian, Palo Alto, USA). 1 Arc, 2 Arc VMAT plans and 7-field IMRT plan were devised for each patient and same values were applied for dose volume constraint and plan normalization. To evaluate these plans, PTV coverage, conformity index (CI) and homogeneity index (HI) were compared and $R_{50%}$ was calculated to assess low dose spillage as per treatment plan. $D_{25%}$ of rectum and bladder Dmean were compared on OAR. And to evaluate the treatment efficiency, total monitor units(MU) and delivery time were considered. Each assessed result was analyzed by average value of 10 patients. Additionally, portal dosimetry was carried out for accuracy verification of beam delivery. Results : There was no significant difference on PTV coverage and HI among 3 plans. Especially CI and $R_{50%}$ on 7F-IMRT were the highest as 1.230, 3.991 respectively(p=0.00). Rectum $D_{25%}$ was similar between 1A-VMAT and 2A-VMAT. But approximately 7% higher value was observed on 7F-IMRT compare to the others(p=0.02) and bladder Dmean were similar among the all plan(P>0.05). Total MU were 494.7, 479.7, 757.9 respectively(P=0.00) for 1A-VMAT, 2A-VMAT, 7F-IMRT and at the most on 7F-IMRT. The delivery time were 65.2sec, 133.1sec, 145.5sec respectively(p=0.00). The obvious shortest time was observed on 1A-VMAT. All plans indicated over 99.5%(p=0.00) of gamma pass rate (2 mm, 2%) in portal dosimetry quality assurance. Conclusion : As a result of study, postoperative prostate cancer radiation therapy for patient using a rectal balloon, there was no significant difference of PTV coverage but 1A-VMAT and 2A-VMAT were more efficient for dose reduction of normal tissue and OARs. Between VMAT plans. $R_{50%}$ and MU were little lower in 2A-VMAT but 1A-VMAT has the shortest delivery time. So it is regarded to be an effective plan and it can reduce intra-fractional motion of patient also.