• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.77-85
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• 2013

Purpose: The accurate movement of gantry rotation, collimator and correct application of dose rate are very important to approach the successful performance of Volumetric Modulated Arc Therapy (VMAT), because it is tightly interlocked with a complex treatment plan. The interruption and restart of dose delivery, however, are able to occur on treatment by various factors of a treatment machine and treatment plan. If unexpected problems of a treat machine or a patient interrupt the VMAT, the movement of treatment machine for delivering the remaining dose will be restarted at the start point. In this investigation, We would like to know the effect of interruptions and restart regarding dose delivery at VMAT. Materials and Methods: Treatment plans of 10 patients who had been treated at our center were used to measure and compare the dose distribution of each VMAT after converting to a form of digital image and communications in Medicine (DICOM) with treatment planning system (Eclipse V 10.0, Varian, USA). We selected the 6 MV photon energy of Trilogy (Varian, USA) and used OmniPro I'mRT system (V 1.7b, IBA dosimetry, Germany) to analyze the data that were acquired through this measurement with two types of interruptions four times for each case. The door interlock and the beam-off were used to stop and then to restart the dose delivery of VMAT. The gamma index in OmniPro I'mRT system and T-test in Microsoft Excel 2007 were used to evaluate the result of this investigation. Results: The deviations of average gamma index in cases with door interlock, beam-off and without interruption on VMAT are 0.141, 0.128 and 0.1. The standard deviations of acquired gamma values are 0.099, 0.091, 0.071 and The maximum gamma value in each case is 0.413, 0.379, 0.286, respectively. This analysis has a 95-percent confidence level and the P-value of T-test is under 0.05. Gamma pass rate (3%, 3 mm) is acceptable in all of measurements. Conclusion: As a result, We could make sure that the interruption of this investgation are not enough to seriously affect dose delivery of VMAT by analyzing the measured data. But this investigation did not reflect all cases about interruptions and errors regarding the movement of a gantry rotation, collimator and patient So, We should continuously maintain a treatment machine and program to deliver the accurate dose when we perform the VMAT for the many kinds of cancer patients.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1159-1166
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• 2009

The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.1
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• pp.71-94
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• 2020

Korea's innovation cluster policy has been implemented since 2005 with the goal of balanced regional development. The purpose of this study is to investigate the factors affecting the sustainability of innovative cluster tenants by using Pangyo Techno Valley as an example. Pangyo Techno Valley was established under the leadership of the local government (Gyeonggi-do) rather than the central government and it is called "Silicon Valley of Korea" and "Asia Silicon Valley" and is becoming more representative. The growing number of companies in Pangyo Techno Valley decreased in 2017 compared to 2016. This is because Pangyo Techno Valley's business ecosystem will change from 2019. In this paper, quantitative and qualitative studies were conducted to investigate the influencing factors. Quantitative research was conducted based on the survey and qualitative research was applied through interviews. The quantitative research examined the factors affecting the sustainability of Pangyo Techno Valley, and the qualitative research examined the specific reasons and additional factors for the quantitative research results. The quantitative results showed that factors affecting sustainability in terms of changes in corporate internal conditions, human and physical infrastructure, cooperation and synergy, and occupancy patterns. The specific reason for the impact appeared in the qualitative research process. The support category of local governments did not show any significant factors in quantitative research. In addition, qualitative research suggested 'Good image of Pangyo Techno Valley' as the category that has the greatest impact on sustainability. It is shown that companies are passive and expect the role of local governments in activating cooperation network in Pangyo Techno Valley. In this paper, based on the results of the study, Pangyo Techno Valley is presented with a realistic plan based on real estate issues and an ideal plan with a long-term perspective.

• Cartoon and Animation Studies
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• s.45
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• pp.147-175
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• 2016

This thesis aims to research ways for the regional balanced development of cartoon creation & production environment being centered in metropolitan area in Korean cartoon industry which has rapidly changed since 2013. As a cartoon can not only be produced with relative lower production cost comparing to those of other cultural contents industries, but also can be produced only if the minimal requirements for cartoon production is prepared, so the cartoon is a field that the decentralization can be accomplished very easily. Currently, most cartoon-relevant companies and cartoon promotion institutions are located in Seoul an Bucheon, etc. However, cartoon artists live nationwide, and even cartoon artists producing their works abroad are reached to a significant number. In some regions like Daejeon, Busan, Suncheon and Gyeongbuk (Gyeongsangbuk-do), there have been appeared full-scale movement to construct regional cartoon creation & production centers since 2015. This thesis aimed to investigate each region's movement to construct cartoon creation & production center with oversea cases, and to check how such movement could be balanced and harmonized with each region's unique features. First of all, this thesis analyzed the status quo of government's policy nurturing the cartoon industry. Korean government's cartoon-promotion policy around the axis of the Cartoon Industry's Mid.Long-Term Development Plan has been developed around the Korea Creative Content Agency and the Korea Manwha(cartoon) Contents Agency in Bucheon, but as the webtoon industry has rapidly grown up, the necessity for building a cartoon promotion institution in each region has been raised since 2015. With the establishment of 4th Cartoon Industry Mid.Long-Term Development Plan to be executed from 2019, it seems that full-scaled support framework for cartoon regional balanced development should be occupied. For the case of foreign countries, cartoon promotion institutions and relevant events have been developed around regions from early times like San-Diego, USA(Comicon), Angouleme, France(National Image Center), Kyoto (Cartoon Museum), Sakaiminato(Misuki Sigeru Road), Japan gave a lot of implications. In the section of conclusion, this study aimed to suggest the importance of and necessity for establishing a cartoon creation & production center in each region appropriately for the region's identity and characteristics with specific plans. Based on that, this thesis aimed to suggest a vision for cartoon & webtoon industry that regional creation & production system can be settled almost only in the cultural contents industry.

• Tuberculosis and Respiratory Diseases
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• v.43 no.5
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• pp.746-754
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• 1996

Objective: Diffuse interstitial lung disease (DILD) is a group of diverse diseases that share conUTIon clinical, radiologic, and pulomonary function features. Open lung biopsy (OLB) has been regarded as gold standard in differential diagnosis of DILD. However open lung biopsy is a invasive diagnostic tool not free of its own risk or complications. These days, high-resolution computed tomography (HRCf) has become an important diagnostic tool in DILD through its precise image analysis. In many instances, HRCT could provide specific diagnosis or, at least, provide infonnation on the disease activity of DILD. The authors re-evaluate the role of open lung biopsy in this "HRCT era" by investigating the additional diagnostic gain and impacts on the treannent plan in patients who have undergone high-resolution CT. Method : Diagnoses obtained by high-resolution CT and open lung biopsy were compared and changes of treatment plans were evaluated retrospectively in 30 patients who had undergone open lung biopsy for the purpose of diagnosis of diffuse interstitial lung disease from March 1988 to June 1994. Results : High-resolution cr suggeted specific diagnoses in 22 out of 28 patients (78.6%) and the diagnoses were confinned (0 be correct by open lung biopy in 20 of those 22 cases (91%). Open lung biopsy could not give specific diagnosis in 5 out of 30 cases (16.7%). In 5 out of 6 cases (83.3%) in whom high reolution cr was not able to suggest specific diagnosis, open lung biopsy gave specific diagnoses. Treatment plan was altered by the result of open lWlg biopsy in only 2 cases. Conclusion: The aoove fmdings suggest that in "HRCT era", when HRCT could suggest specific diagnosis, the need for open lung biopsy should be re-evaluated.

• Journal of the Korean association of regional geographers
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• v.11 no.4
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• pp.453-462
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• 2005

The study deals with surface erosion patterns due to the development of cropland toward hillslope and hilltop in the Oncheon-gun, pyeongbuk province and Nampo city of west coast area in the North Korea, using Quick Bird satellite images with 60cm resolution. In North Korea, for national economic difficult after 1980 year, newly developed croplands have been along the gentle hillslope, in which it is possible for individual man power different from the tideland which needs large scaled man-power and equipment. The new croplands are named Darakbat(terraced farm with embankment) and Bitalbat(titled farm developed on the original hill slope), neighboring with orchard and grouped settlement in lower valley. For supplying agricultural water, irrigation ditches and temporal crop storages have been constructed, connecting Darakbat, Bitalbat and orchard. These cropland developments have caused surface erosion composed of 3 types such as pit, linear and headward erosion, together with rill and gully. Owing to poor management of cropland and irrigation system, topsoil erosion and, collapse and sedimentation of ditch and pool, caused the decrease of agricultural productivity. These analysis using Quick Bird images can suggest original raw data about geographical facts on North Korea agriculture and help to recover their agricultural system and plan future national unified land.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.63-68
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• 2010

The ultimate goal of radiation treatment is to use enough radiation dosage in order to examine a tumor while protecting normal tissue. Respiratory guided radiotherapy is being clinically implemented to examine a given stabilized area in order to compensate for the problems of patient breathing. This study investigates the effects of breathing movements on 40 patients with liver cancer through the actual radiation therapy plan using 4D-CT and respiratory guided radiotherapy using RPM. Using a commercial RPM respiratory gating system 4D-CT, we acquired 4D CT on multislice helical CT scanners that use different approaches to 4D CT image reconstruction. The results from analyzing forty patients according to age and direction showed no relationship between gender and transition change. The mean left-right, anteroposterior, and craniocaudal total movements were $3.19{\pm}1.29$, $5.44{\pm}2.07$, and $12.54{\pm}4.70$ mm, respectively. Changes were the largest with CC directions and as patients advanced in age, movements were larger. Therefore, as changes occur in treatment areas because of movements caused from breathing, respiratory gating system is put into operation to revise movement and can increase the radiotherapeutics effects in treating liver cancer.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.391-403
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• 2005

Vision is the most important sense of the five senses in our body. This represents that an eye is for the mysterious organ playing the essential role in our body. Alain Mikli known as a famous spectacle designer in France said that glasses exists for seeing and for being seen. This saying is one of the philosophically well-organized definition of the most fundamental function of eye-glasses described in and out of itself. Today, in the world, there are a number of works of glasses design and lots of glasses designers are designing hard in order to convey the goods with the best value and philosophy to customers. They work for the goal that glasses is used as seeing and try to give customers satisfaction and enjoyment of it. And they think that glasses should play the role of the interface. At this point, we need to catch hold of the interface of glasses. That means that glasses has to have the communication between eyes and objects and be the mediation of the connection between the image of oneself and that of one by others. For the character of the interface of glasses, glasses designers should plan and investigate this character at the being of design. This study of optical art has been researched for the necessary and sufficient condition between consumers and products.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.564-567
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• 2012

Optical fibers are going to be used for telecommunication, image fibers, sensors under irradiation in nuclear power plants and various irradiation facilities. Especially, Temperature detection sensors using Raman light scattering, temperature or strain sensors using fiber gratings, magnet-optical sensors using photo-magnetic effect, are already commercialized. However, When fibers are exposed to ionizing radiation, color centers are formed in fibers which reduces their light transmission, and it is limited in applying under radiation environments. In this study, $Co^{60}$ gamma-ray induced optical attenuation on Ge-doped single mode(SM) fiber has been measured. Gamma-ray is irradiated for 4hours at the dose rate of 0.5kGy/hr, 2kGy/hr, 8kGy/hr. Consequently, gamma-ray induced loss based on radiation effects in Ge-doped SM fiber occur precisely. Furthermore, dose rate effect that the higher dose rate in the same total dose, the more increase loss of optical fiber and annealing effect that the higher the loss after irradiation, the more increase the recovery rate of the loss are observed in the fiber. This results plan to make use of bases in the study of the radiation-hardened optical fiber.

• The Journal of the Acoustical Society of Korea
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• v.39 no.1
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• pp.16-23
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• 2020

In High-Intensity Focused Ultrasound (HIFU) treatment, effective localization of HIFU focus is important for developing a safe treatment plan. While Magnetic Resonance Imaging guided HIFU (MRIgHIFU) can visualize the ultrasound path during the treatment for localizing HIFU focus, it is challenging in ultrasound imaging guided HIFU (USIgHIFU). In the present study, a real-time ultrasound beam visualization technique capable of localizing HIFU focus is presented for USIgHIFU. In the proposed method, a short pulse, with the same center frequency of an imaging ultrasound transducer below the regulated acoustic intensity (i.e., Ispta < 720 mW/㎠), was transmitted through a HIFU transducer whereupon backscattered signals were received by the imaging transducer. To visualize the HIFU beam path, the backscattered signals underwent dynamic receive focusing and subsequent echo processing. From in vitro experiments with bovine serum albumin gel phantoms, the HIFU beam path was clearly depicted with low acoustic intensity (i.e., Ispta of 94.8 mW/㎠) and the HIFU focus was successfully localized before any damages were produced. This result indicates that the proposed ultrasound beam path visualization method can be used for localizing the HIFU focus in real time while minimizing unwanted tissue damage in USIgHIFU treatment.