• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.77-84
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• 2017

Purpose: To evaluate the image quality improvement and dosimetric effects on virtual monochromatic images of a Dual Source-Dual Energy CT(DS-DECT) for radiotherapy planning. Materials and Methods: Dual energy(80/Sn 140 kVp) and single energy(120 kVp) scans were obtained with dual source CT scanner. Virtual monochromatic images were reconstructed at 40-140 keV for the catphan phantom study. The solid water-equivalent phantom for dosimetry performs an analytical calculation, which is implemented in TPS, of a 10 MV, $10{\times}10cm^2$ photon beam incident into the solid phantom with the existence of stainless steel. The dose profiles along the central axis at depths were discussed. The dosimetric consequences in computed treatment plans were evaluated based on polychromatic images at 120 kVp. Results: The magnitude of differences was large at lower monochromatic energy levels. The measurements at over 70 keV shows stable HU for polystyrene, acrylic. For CT to ED conversion curve, the shape of the curve at 120 kVp was close to that at 80 keV. 105 keV virtual monochromatic images were more successful than other energies at reducing streak artifacts, which some residual artifacts remained in the corrected image. The dose-calculation variations in radiotherapy treatment planning do not exceed ${\pm}0.7%$. Conclusion: Radiation doses with dual energy CT imaging can be lower than those with single energy CT imaging. The virtual monochromatic images were useful for the revision of CT number, which can be improved for target coverage and electron densities distribution.

• Journal of radiological science and technology
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• v.26 no.4
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• pp.39-46
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• 2003

Digital radiographic systems based on solid-state detectors, commonly referred to as flat-panel detectors, are gaining popularity in clinical practice. Large area, flat panel solid state detectors are being investigated for digital radiography. The purpose of this work was to evaluate the active matrix flat panel digital x-ray detectors in terms of their modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). In this paper, development and evaluation of a selenium-based flat-panel digital x-ray detector are described. The prototype detector has a pixel pitch of $139\;{\mu}m$ and a total active imaging area of $14{\times}8.5\;inch^2$, giving a total 3.9 million pixels. This detector include a x-ray imaging layer of amorphous selenium as a photoconductor which is evaporated in vacuum state on a TFT flat panel, to make signals in proportion to incident x-ray. The film thickness was about $500\;{\mu}m$. To evaluate the imaging performance of the digital radiography(DR) system developed in our group, sensitivity, linearity, the modulation transfer function(MTF), noise power spectrum (NPS) and detective quantum efficiency(DQE) of detector was measured. The measured sensitivity was $4.16{\times}10^6\;ehp/pixel{\cdot}mR$ at the bias field of $10\;V/{\mu}m$ : The beam condition was 41.9\;KeV. Measured MTF at 2.5\;lp/mm was 52%, and the DQE at 1.5\;lp/mm was 75%. And the excellent linearity was showed where the coefficient of determination ($r^2$) is 0.9693.

• Korean Security Journal
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• no.29
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• pp.193-222
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• 2011

Our country successfully hosted the G20 summit in Seoul in November, 2010. Afterwards, however, the Yeonpyungdo shelling incident took place by the North, and the North Korean nuclear issue have strained interKorean relations. Our country is going to host the nuclear security summit, which is of great significance at this point of time. The nuclear security summit is to be attended by 47 countries. The participant countries of this summit is larger in number than those of the ASEM, APEC and the G20 summit that our country has ever hosted. That is a large-scale international conference that invites the UN, the IAEA and the EU, which are three major nuclear-related international organizations. A successful hosting of the nuclear security summit will serve as an opportunity to boost our country's national prestige, and is likely be beneficial to the settlement of the North Korean nuclear issue. Like other international submits in foreign countries, however, violent anti-globalization demonstrations are expected to occur when the nuclear security summit is held in April next year. The purpose of this study was to make a case analysis of demonstrations during multilateral international conferences hosted by foreign countries over ten years between 1999 and 2009, to examine the controversial points over the demonstrations, and ultimately to seek ways of ensuring safety against possible assemblies and demonstrations during the forthcoming nuclear security summit, which is scheduled to be held in April next year. The findings of the study on feasible security measures are as follows: First, information and intelligence gathering should be reinforced, and the inspection should be stepped up. Second, pacification among domestic NGOs and the supplementation of the existing legal devices are required. Third, publicity should be strengthened. Fourth, riot police officers should be selected as early as possible to bolster their education and training, and more reinforced emergency measures should be taken. It's needed to seek assistance from the military as one of emergency measures, and national defense readiness should be bolstered across the nation in collaboration with the Ministry of National Defense when the summit is near at hand. Finally, CBR countermeasures should be taken in preparation for CBR terrorism.

• Korean Security Journal
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• no.28
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• pp.181-205
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• 2011

There are various discussions about introducing private investigation in South Korea these days, and training private investigators is one of the main topics. Training private investigators, unlike other training, is required to instill expertise and ethical quality into the trainees since the major task of the investigators includes protecting the lives of the citizens as well as their properties. Therefore, many agree to the idea that systematic educational programs need to be organized to produce private investigators with expertness and morality. In this study, we explored the opinions of those who are concerned with this issue of establishing private investigation in the university education and analyzed the data by using the NVivo 2 program. The result revealed that the reasons that people supported the idea of launching private investigator services were as follows. First, there is lack of manpower to maintain peace and public order in the country. Second, the police does not intervene actively and help harmed victims unless it is a consequential incident. Third, in position to wield public power, police officers cannot get involved in civil affairs. Also, absence of an academic institution to educate private investigators and lack of the police and clients' trust in private investigation were the two biggest reasons that people approved the proposal to introduce department of private investigation in universities. The interviewees of the study believed the outlook and future direction for private investigation would change depending on the status of the licensed private investigation business bill. Before the bill passes, they thought that the work of private investigators will be performed by insurance companies, foreign private investigation businesses, domestic consulting firms, and security providers which supply similar services. On the other hand, after the bill passes, they believed that numerous private investigator corporations resembling existing security corporations will be founded in addition to the current market, and that private investigation in the academic field will also be vitalized.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.233-241
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• 2011

Currently, solar module is using the two methods such as a glass-filled method or a super-straight method. The common point of these methods is to use glass structure on the front of solar module. However, the reflectance of the solar module is high depending on the height of the incident sunlight due to the flat surface of the module front glass. Purposed to solve these problems, AG (anti-glare) structures were formed on the glass surface. Next is fabrication methods of AG structure. First, uneven structure made by micro blaster equipment was dipped in Hydro-fluidic acid (HF) acid. HF acid process was carried out to remove particles and to make high transmittance. The reflectance and transmittance of the anti-glare glass was compared to those of the bare glass. The reflectance of anti-glare glass decreased approximately 1% compared with bare glass. The transmittance of anti-glare glass was similar to bare glass. According to the sample angle, the difference of the reflectance between bare glass and the anti-glare glass was about 19%. Isc and efficiency value of anti-glare glass on bare solar cell appeared about 3.01 mA and 0.228% difference compared with bare glass. Anti-glare glass on textured solar cell appeared about 9.46 mA and 0.741% difference compared with bare glass. As a result, the role of anti-glare in the substrate is to reduces the loss of sunlight reflected from the surface. In this study, therefore, AG structure on the solar cell was used to improve the efficiency of solar cell.

• The Korean Society of Law and Medicine
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• v.16 no.2
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• pp.27-53
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• 2015

Recently, a plastic surgery hospital in Seoul, has been raided following suspicions that ghost surgery was performed by an unauthorized substitute surgeon on a chinese woman who lapsed into a death. Following the incident, an organization to eradicate ghost surgery was created in March by Consumers Korea, founded to protect consumer rights, and the Korea Alliance of Patients Organization. The organization has received reports of illegal medical practices. To substitute another physician without the patient's consent and without his knowledge of the substitution is fraud and deceit and a violation of a basic ethical concept. The patient as a human being is entitled to choose his own physician and he should be permitted to acquiesce in or refuse to accept the substitution. It should be noted that it is the operating surgeon to whom the patient grants his consent to perform the operation. The patient is entitled to the services of the particular surgeon with whom he contracts. The surgeon, in accepting the patient, obligates himself to utilize his personal talents in the performance of the operation to the extent required by the agreement creating the physician-patient relationship. He cannot properly delegate to another the duties which the patient authorizes him to perform personally. 'Ghost surgery' comes under Article 257(Inflicting Bodily Injury on Other or on Lineal Ascendant) of the Criminal Code. Substitution another physician without the patient's consent and without his knowledge of the substitution shall be performed Inflicting Bodily Injury. This is a controversial issue that'ghost surgery' comes under Article 347(Fraud) of the Criminal Code. It maybe controversial that operation substituted by another physician without the patient's consent and without his knowledge of the substitution becomes the component of Fraud. Also, Ghost surgery' comes under Article 27 (Prohibition of Unlicensed Medical Practice, etc.), Article 22 (Medical Records, etc.), Article 33 (Establishment) of the Medical Service Act. The surgeon's obligation to the patient requires him to perform the surgical operation: (1) within the scope of authority granted him by the consent to the operation; (2) in accordance with the terms of the contractual relationship; (3) with complete disclosure of all facts relevant to the need and the performance of the operation; and (4) to utilize his best skill in performing the operation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.43-56
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• 2005

This research has examined a time series analysis(TSA) of an every hour traffic information such as occupancy, a traffic flow, and a speed, a statistical model of a surveyed data on the traffic fundamental diagram and an expand aspect of a traffic jam by many Parts of the traffic flow. Based on the detected data from traffic accidents on the Cheonan-Nonsan high way and events when the road volume decreases dramatically like traffic accidents it can be estimated from the change of occupancy right after accidents. When it comes to a traffic jam like events the changing gap of the occupancy and the mean speed is gentle, in addition to a quickness and an accuracy of a detection by the time series analyse of simple traffic index is weak. When it is a stable flow a relationship between the occupancy and a flow is a linear, which explain a very high reliability. In contrast, a platoon form presented by a wide deviation about an ideal speed of drivers is difficult to express by a statical model in a relationship between the speed and occupancy, In this case the speed drops shifty at 6$\~$8$\%$ occupancy. In case of an unstable flow, it is difficult to adopt a statistical model because the formation-clearance Process of a traffic jam is analyzed in each parts. Taken the formation-clearance process of a traffic jam by 2 parts division into consideration the flow having an accident is transferred to a stopped flow and the occupancy increases dramatically. When the flow recovers from a sloped flow to a free flow the occupancy which has increased dramatically decrease gradually and then traffic flow increases according as the result analyzed traffic flow by the multi regime as time series. When it is on the traffic jam the traffic flow transfers from an impeded free flow to a congested flow and then a jammed flow which is complicated more than on the accidents and the gap of traffic volume in each traffic conditions about a same occupancy is generated huge. This research presents a need of a multi-regime division when analyzing a traffic flow and for the future it needs a fixed quantity division and model about each traffic regimes.

• Korean Journal of Remote Sensing
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• v.25 no.1
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• pp.31-44
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• 2009

The objective of this study was to measure backscattering coefficients of paddy rice using a L-, C-, and X-band scatterometer system with full polarization and various angles during the rice growth period and to relate backscattering coefficients to rice growth parameters. Radar backscattering measurements of paddy rice field using multifrequency (L, C, and X) and full polarization were conducted at an experimental field located in National Academy of Agricultural Science (NAAS), Suwon, Korea. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer ($20\;MHz{\sim}20\;GHz$), RF cables, and a personal computer that controls frequency, polarization and data storage. The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ with $5^{\circ}$ interval for four polarization (HH, VV, HV, VH), respectively. We measured the temporal variations of backscattering coefficients of the rice crop at L-, C-, X-band during a rice growth period. In three bands, VV-polarized backscattering coefficients were higher than hh-polarized backscattering coefficients during rooting stage (mid-June) and HH-polarized backscattering coefficients were higher than VV-, HV/VH-polarized backscattering coefficients after panicle initiation stage (mid-July). Cross polarized backscattering coefficients in X-band increased towards the heading stage (mid-Aug) and thereafter saturated, again increased near the harvesting season. Backscattering coefficients of range at X-band were lower than that of L-, C-band. HH-, VV-polarized ${\sigma}^{\circ}$ steadily increased toward panicle initiation stage and thereafter decreased, and again increased near the harvesting season. We plotted the relationship between backscattering coefficients with L-, C-, X-band and rice growth parameters. Biomass was correlated with L-band hh-polarization at a large incident angle. LAI (Leaf Area Index) was highly correlated with C-band HH- and cross-polarizations. Grain weight was correlated with backscattering coefficients of X-band VV-polarization at a large incidence angle. X-band was sensitive to grain maturity during the post heading stage.

• Korea and Global Affairs
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• v.3 no.2
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• pp.5-58
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• 2019

The purpose of this article is to bring about 10.26 accident by providing a fuse for the overthrow of the Park Chung-hee administration in the 10.18 Buma uprising. So, first of all, this article has a main purpose in analyzing the comparison between Masan's 3.15 uprising and 10.18 Buma uprising. The purpose of the study is to compare the 3.15 democratic movement in Masan with the 10.18 Buma uprising, given that the incident laid the foundation for the dictator to be overthrown in the event of an anti-dictatorial movement in Masan. The research method of this article is intended to be used as a research method in the 3.15 and 10.18 protests, given that if a person in power conducts election fraud or suppresses anti-government movements in order to maintain the system, it could lead to the destruction of those in power. In the end, the Masan 3.15 uprising and 10.18 uprising failed to reach a direct attempt to overthrow the regime due to unfinished democratic movements, but with the revolution of 4.19 and the massive political transformation of 10.26 Accident, he achieved the leading role theory that allowed the Rhee Syngman and Park Chung-hee administrations. In eradicating authoritarian regimes, however, the historic significance of the democratization movement was that the authoritarian regime eventually brought about the collapse of the regime by making a hard-line stance on election schemes or popular protests over the trap of power boomerang, which causes the regime to collapse.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.5
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• pp.265-277
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• 2019

Using the measured data of waves and shore-line, we reviewed the grand circulation process and seasonal variation of beach cusp at the Mang-Bang beach from the perspective of trapped mode Edge waves known as the driving mechanism of beach cusp. In order to track the temporal and spatial variation trends of beach cusp, we quantify the beach cusp in terms of its wave length and amplitude detected by threshold crossing method. In doing so, we also utilize the spectral analysis method and its associated spectral mean sand wave number. From repeated period of convergence and ensuing splitting of sand waves detected from the yearly time series of spectral mean sand wave number of beach cusp, it is shown that the grand circulation process of beach cusp at Mang-Bang beach are occurring twice from 2017. 4. 26 to 2018. 4. 20. For the case of beach area, it increased by $14,142m^2$ during this period, and the shore-line advanced by 18 m at the northen and southern parts of the Mang-Bang beach whereas the shore-line advanced by 2.4 m at the central parts of Mang-Bang beach. It is also worthy of note that the beach area rapidly increased by $30,345m^2$ from 2017.11.26. to 2017.12.22. which can be attributed to the nature of coming waves. During this period, mild swells of long period were prevailing, and their angle of attack were next to zero. These characteristics of waves imply that the main transport mode of sediment would be the cross-shore. Considering the facts that self-healing capacity of natural beaches is realized via the cross-shore sediment once temporarily eroded. it can be easily deduced that the sediment carried by the boundary layer streaming toward the shore under mild swells which normally incident toward the Mang-Bang beach makes the beach area rapidly increase from 2017.11.26. to 2017.12.22.