• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.3-7
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• 2010

Purpose: The usefulness of Positron Emission Tomography (PET) images in diagnosis, staging, recurrent and treatment response evaluation has already been known. However, tumors which are small size, located in lower lobe of lung or upper lobe of liver are shown misalignment, distortion and different Standard Uptake Value (SUV) by respiration in PET images. Therefore, if radiotherapy based on normal respiration, it may cause low treatment response or more side effects because targets which had to treat, out of treat range or over dose to normal tissue. The purpose of this study is to evaluate attenuation-correction with Average CT (ACT) for more accuracy SUV measurement and minimize artifact by respiration. Materials and Methods: 13 patients, who had tumors which are around the diaphragm, underwent ACT scan after Helical CT (HCT) scan with PET/CT (Discovery DSTE 8; GE Healthcare). We quantified the differences between attenuation corrected image with HCT and attenuation corrected image with ACT in artifact size and maximum SUV ($SUV_{max}$). Artifacts were evaluated by measurement of the curved photogenic area in the lower thorax of the PET images for all patients. $SUV_{max}$ was measured separately at the primary tumors. Analysis program was Advantage Workstation v4.3 (GE Healthcare). Patients were injected with 7.4 MBq (0.2 $mC_i$) per kg of $^{18}F$-FDG and scanned 1 hour after injection. The PET acquisition was 3 minute per bed. Results: Significantly lower artifact were observed in PET/ACT images than in PET/HCT images (below-thoracic artifacts caused by under corrected $1.5{\pm}3.5$ cm vs. $13.4{\pm}4.2$ cm). Significantly higher $SUV_{max}$ were noted in PET/ACT images than in PET/HCT images in the primary tumor. Compared with PET/HCT images, $SUV_{max}$ in PET/ACT images were higher by $5.3{\pm}3.9%$ (mean value) tumor. The highest difference was observed in Lower lobe of lung (7.7 to 8.7; 13%). Conclusion: Due to its significantly reduced artifacts in lower thoracic, attenuation corrected image with ACT images provided more reliable $SUV_{max}$ and may be helpful in monitoring treatment response. Moreover, ACT can separate upper lobe of liver and lower lobe of lung, it may be helpful in interpretation. ACT will be clinically useful, considering increased dose caused by ACT scan and adapt.

• 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.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.62-68
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• 2014

Purpose: After I-131 therapy, SPECT/CT is useful in identifying location of thyroid remnants and metastasis of thyroid cancers. An excessive uptake of thyroid leads to a ringing artifact in the SPECT images. The aim of this study is to investigate and suggest a proper post filters to remove ringing artifact and produce better image quality. Materials and Methods: A low-cost, customized thyroid-mimicking phantom, consisting of an acrylic bottle and a hollow sphere was used for SPECT/CT Discovery (GE Healthcare, USA). It was filled with I-131 solution. The ratio of hollow sphere to background were varied as 50:1, 200:1, 1000:1 and 4000:1. Acquired images were reconstructed by OSEM (2 iterations, 10 subsets) with and without Evolution (resolution recovery correction, GE). Three different post-filters were applied; Butterworth (cut off: 0.38 to 0.58 with intervals of 0.05), Hanning (cut off: 0.8 to 1 with intervals of 0.05) and Gaussian (FWHM: 3 to 5 with intervals of 0.5) filters. Contrast, background variability, air area variability, and full width half maximum (FWHM) were compared. Results: Higher contrasts were obtained from the SPECT images with Evolution than without Evolution. In the case of images without Evolution, image distortion such as star artifact was generated. For all sphere-to-background ratio, the Butterworth filter showed better constrasts and FWHMs than other two filters, but the ringing artifact was still generated in all studies except 50:1 and it was decreased as cutoff value was increased. The ringing artifact didn't appear with Hanning and Gaussian filters at all studies, however constrats and FWHMs with Gaussian was worse than Hanning filter. For the images having ringing artifacts, the background variability and air area variability were increased. Conclusion: In this study, we suggested that it is desirable to use Hanning filter when the ringing artifact is generated and to use Butterworth filter when ringing artifact is not generated in I-131 SPECT.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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• pp.360-365
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• 1999

This study was aimed to suggest to better treatment method of jaw cyst that the maximum diameter was wider than 3cm, using different treatment and clinical and radiographic result. We divided the 60 patients into three groups, group A(20 patients) were treated with cyst enucleation and Decalcified Freeze-Dried Allogeneic Bone(DFDB) graft, group B(20 patients) were treated with cyst enucleation and autogenous bone graft, group C(20 patients) were treated with only cyst enucleation. Each group was evaluated with panoramic radiograph and clinical sign & symptom at pre-op and post-op(immediate, 6, 12, 24, 36 month). Bone density was evaluated with disital densitometer. The result was as follows : 1. Post-Op infection was higher in group C(4 pts.) than in group A(1 pt.) and B(1 pt.) 2. Post-Op gingival recession was higher in group C(3 Pts.) than in group A(1 pt.) and B(1 pt.) 3. Anatomic distortion was higher in group C(3 Pt.) than in group A(1 Pt.), and B(1 pt.) 4. Reoperation was done in two patients who were in group C 5. There were donor site morbidity in two patients 6. There was no significant difference between group A and B in their bony density in their follow up period(p>0.05). 7. There were significant differences between group A, B and group C in their bony density until post-op 24 months but a little differences at post-op 36 months(P<0.01)

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.55-60
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• 2010

Purpose: The shrinkage of dental resin cement may cause several clinical problems such as distortion that may jeopardize the accurate fit to the prepared tooth and internal stress within the restorations. It is important to know the polymerization shrinkage-strain of dental resin cement to reduce clinical complications. The purpose of this study was to investigate the polymerization shrinkage-strain kinetics of six commercially available dental resin cements. Material and methods: Three self-cure resin cements (Fujicem, Superbond, M-bond) and three dual-cure resin cements (Maxcem, Panavia-F, Variolink II) were investigated. Time dependent polymerization shrinkage-strain kinetics of the materials were measured by the Bonded-disk method as a function of time at $23^{\circ}C$, with values particularly noted at 1, 5, 10, 30, 60, 120 min after mixing. Five recordings were taken for each materials. The data were analyzed with one-way ANOVA and Scheffe post hoc test at the significance level of 0.05. Results: Polymerization shrinkage-strain values were 3.72%, 4.19%, 4.13%, 2.44%, 7.57%, 2.90% for Fujicem, Maxcem, M bond, Panavia F, Superbond, Variolink II, respectively at 120 minutes after the start of mixing. Panavia F exhibited maximum polymerization shrinkage-strain values, but Superbond showed minimum polymerization shrinkage-strain values among the investigated materials (P < .05). There was no significant differences of shrinkage-strain value between Maxcem and M bond at 120 minutes after the start of mixing (P > .05). Most shrinkage of the resin cement materials investigated occurred in the first 30 minutes after the start of mixing. Conclusion: The onset of polymerization shrinkage of self-cure resin cements was slower than that of dual-cure resin cements after mixing, but the net shrinkage strain values of self-cure resin cements was higher than that of dual-cure resin cements at 120 minutes after mixing. Most shrinkage of the dental resin cements occurred in the first 30 minutes after mixing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.5
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• pp.258-270
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• 2014

In this paper, we investigate channel capacity of two kinds of uplink OFDMA (Orthogonal Frequency Division Multiple Access) schemes, i.e. ZCZ (Zero Correlation Zone) code time-spread OFDMA and sparse SC-FDMA (Single Carrier Frequency Division Mmultiple Access) robust to access timing offset (TO) among multiple users. In order to reflect the practical condition, we consider not only access TO among multiple users but also peak to average power ratio (PAPR) which is one of hot issues of uplink OFDMA. In the case with access TO among multiple users, the amplified signal of users by power control might affect a severe interference to signals of other users. Meanwhile, amplified signal by considering distance between user and base station might be distorted due to the limit of amplifier and thus the performance might degrade. In order to achieve the maximum channel capacity, we investigate the combinations of transmit power so called ASF (adaptive scaling factor) by numerical simulations. We check that the channel capacity of the case with ASF increases compared to the case with considering only distance i.e. ASF=1. From the simulation results, In the case of high signal to noise ratio (SNR), ZCZ code time-spread OFDMA achieves higher channel capacity compared to sparse block SC-FDMA. On the other hand, in the case of low SNR, the sparse block SC-FDMA achieves better performance compared to ZCZ time-spread OFDMA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.628-634
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• 2016

Many pitchers suffer from various types of injury (distortion, sprain and so on). The rate of injury is increased if there are differences in strength between the extensor and flexor muscles when a joint movement is performed with maximum speed. However, there has been insufficient research into the injury caused by strength differences between the extensor and flexor muscles. Thus, the purpose of the study was to examine the effects of elbow ulnar collateral ligament injury on the maximal isometric strength in young baseball pitchers. The data collection was conducted for 2 weeks. The subjects (n=36) who participated in this study were placed into either the injury group (n = 18, IG) or normal group (n = 18, NG). The maximal isometric strength for the pectoralis major (PM), infraspintus (I), biceps brachii (BB), triceps brachii (TB), flexor carpi radialis (ECR) and extensor carpi radialis (FCR) muscles were determined by an isometric strength machine (K-DFX) and then the differences in strength were calculated by muscle group. All of the data were analyzed by SPSS 18.0 with the independent t-test. In the results, the maximal isometric strengths in the IG for the I (p=0.035), BB (p=0.031) and TB (p=0.041) were significantly lower than those in the NG, while that for the ECR (p=0.047) was significantly greater. In addition, the differences of the maximal isometric strength between the PM and I (p = 0.008), BB and TB (p = 0.002), and FCR and ECR (p = 0.032) in the IG were significantly greater than those in the NG. In conclusion, the differences in muscle strengths of the subjects in the IG were greater than those in the NG, which suggests that they might have a higher injury rate in the future. However, they might be able to recover from their injury and achieve better performance if the differences in strength were reduced by training.

• Korean Journal of Remote Sensing
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• v.21 no.6
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• pp.445-456
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• 2005

The land surface parameters should be determined with sufficient accuracy, because these play an important role in climate change near the ground. As the surface reflectance presents strong anisotropy, off-nadir viewing results a strong dependency of observations on the Sun - target - sensor geometry. They contribute to the random noise which is produced by surface angular effects. The principal objective of the study is to provide a database of accurate surface reflectance eliminated the angular effects from MODIS 250m reflective channel data over Korea. The MODIS (Moderate Resolution Imaging Spectroradiometer) sensor has provided visible and near infrared channel reflectance at 250m resolution on a daily basis. The successive analytic processing steps were firstly performed on a per-pixel basis to remove cloudy pixels. And for the geometric distortion, the correction process were performed by the nearest neighbor resampling using 2nd-order polynomial obtained from the geolocation information of MODIS Data set. In order to correct the surface anisotropy effects, this paper attempted the semiempirical kernel-driven Bi- directional Reflectance Distribution Function(BRDF) model. The algorithm yields an inversion of the kernel-driven model to the angular components, such as viewing zenith angle, solar zenith angle, viewing azimuth angle, solar azimuth angle from reflectance observed by satellite. First we consider sets of the model observations comprised with a 31-day period to perform the BRDF model. In the next step, Nadir view reflectance normalization is carried out through the modification of the angular components, separated by BRDF model for each spectral band and each pixel. Modeled reflectance values show a good agreement with measured reflectance values and their RMSE(Root Mean Square Error) was totally about 0.01(maximum=0.03). Finally, we provide a normalized surface reflectance database consisted of 36 images for 2001 over Korea.