• Journal of radiological science and technology
• /
• v.43 no.2
• /
• pp.105-114
• /
• 2020

This study aimed to assess of beam-matching accuracy for an 8 MV beam between the same model linear accelerators(Linac) commissioned over two years. Two models were got the customer acceptance procedure(CAP) criteria. For commissioning data for beam-matched linacs, the percentage depth doses(PDDs), beam profiles, output factors, multi-leaf collimator(MLC) leaf transmission factors, and the dosimetric leaf gap(DLG) were compared. In addition, the accuracy of beam matching was verified at phantom and patient levels. At phantom level, the point doses specified in TG-53 and TG-119 were compared to evaluate the accuracy of beam modelling. At patient level, the dose volume histogram(DVH) parameters and the delivery accuracy are evaluated on volumetric modulated arc therapy(VMAT) plan for 40 patients that included 20 lung and 20 brain cases. Ionization depth curve and dose profiles obtained in CAP showed a good level for beam matching between both Linacs. The variations in commissioning beam data, such as PDDs, beam profiles, output factors, TF, and DLG were all less than 1%. For the treatment plans of brain tumor and lung cancer, the average and maximum differences in evaluated DVH parameters for the planning target volume(PTV) and the organs at risk(OARs) were within 0.30% and 1.30%. Furthermore, all gamma passing rates for both beam-matched Linacs were higher than 98% for the 2%/2 mm criteria and 99% for the 2%/3 mm criteria. The overall variations in the beam data, as well as tests at phantom and patient levels remains all within the tolerance (1% difference) of clinical acceptability between beam-matched Linacs. Thus, we found an excellent dosimetric agreement to 8 MV beam characteristics for the same model Linacs.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.2
• /
• pp.22-29
• /
• 2020

Among many fire-related laws and standards such as fire protection, fire doors are important facilities that play a role in preventing the spread of fire and smoke in the event of fire, thereby minimizing human casualties. Accordingly, the standards for performance required by applicable laws and regulations and related enforcement rules and notices have been continuously raised and the corresponding performance must be secured. However, due to the shortcomings of the relevant laws and systems, the test results of the fire doors confirmed that there was a risk of passing products. In this study, the criteria for fire-related performance were analyzed, and the performance required by other laws, in addition to simple fire protection, was identified, the criteria were organized, and the complex performance required was clearly.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.5
• /
• pp.991-1000
• /
• 2021

Among non-invasive blood glucose detection technologies, the optical technique is a method that uses light reflection, absorption, and scattering characteristics when passing through a biological medium. It reduces pain or discomfort in measurement and has no risk of infection. So it is becoming a major flow of blood glucose detection research. Among them, near-infrared spectroscopy has a disadvantage in that the complexity increases when analyzing signals detected due to interferences between proteins and acids that share a similar absorption function with blood glucose molecules. In this study, a non-invasive sensor system with multiple near-infrared bands was designed and manufactured to alleviate the deterioration of blood glucose detection function that may occur due to skin absorption of near-infrared rays. A blood survey was conducted to verify the system, and the degree of blood glucose response in the blood was collected as spectral data, and the results of this study were quantitatively verified in terms of correlation between the data and blood glucose.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.7 no.2
• /
• pp.67-74
• /
• 2008

Repetitive overhead throwing exerts significant mechanical stress on the elbow joint. Pitching in baseball, serving in tennis, spiking in volleyball, passing in American football and launching in javelin-throwing can all produce elbow pathology by forceful valgus stress, with medial stretching, lateral compression and posterior impingement. This stress can lead to developmental anatomic changes in the young thrower. Asymptomatic pathology in the shoulder and elbow joint is prevalent and, with overuse, can progress to disabling injury. Joint injury occurs as a result of the body's inability to properly coordinate motion segments during the pitching delivery, leading to further structural damage. The implications of acute and overuse injuries and the possibility of permanent damage should be understood by parents, coaches and the athletes. Proper understanding of the intrinsic and extrinsic risk factors that could lead to elbow injuries is thus required. Measures to prevent elbow injuries should include proper coaching, warm-up, medical expertise and protective gear. Injury prevention and rehabilitation should center on optimizing pitching mechanics, core strength, scapular control, and joint range of motion.

• Journal of Korea Multimedia Society
• /
• v.14 no.2
• /
• pp.228-237
• /
• 2011

The risk of leakage or theft of critical data which is stored in database is increasing in accordance with evolution of information security paradigm. At the same time, needs for database security have been on the rapid increase due to endless leakage of massive personal information. The existing technology for prevention of internal information leakage possesses the technical limitation to achieve security goal completely, because the passive control method including a certain security policy, which allows the only authorized person to access to DBMS, may have a limitation. Hence in this study, we propose Query Signature System which signatures the queries accessing to the critical information by interrupting and passing them. Furthermore this system can apply a constant security policy to organization and protect database system aggressively by restricting critical query of database.

• Journal of Platform Technology
• /
• v.9 no.4
• /
• pp.90-96
• /
• 2021

Most of the vehicles currently under development and in operation are equipped with various IoT sensors, but some of the factors that cause car accidents are relatively difficult to detect. One of the major risk factors among these factors is black ice. Black ice is one of the factors most likely to cause major accidents, as it can affect all vehicles passing through areas covered with black ice. Therefore, black ice detection technique is essential to prevent major accidents. For this purpose, some studies have been carried out in the past, but unrealistic factors have been reflected in some parts, so research to supplement this is needed. In this paper, we tried to detect black ice by analyzing color images using the CNN technique, and we succeeded in detecting black ice to a certain level. However, there were differences from previous studies, and the reason was analyzed.

• Korean journal of applied entomology
• /
• v.58 no.3
• /
• pp.183-187
• /
• 2019

To establish the cooperative monitoring network which can investigate introductions or outbreaks of high risk insect pests into Korea, seven universities, Gyeongsang National University, Kunsan National University, Seoul National University, Sunchon National University, Andong National University, Jeju National University, and Chungbuk National University, carried out seven regions' monitoring about nine high risk insect pests, Aceria diospyri, Bactrocera dorsalis, Bactrocera minax, Bactrocera tsuneonis, Cydia pomonella, Lobesia botrana, Proeulia sp., Solenopsis invicta, Stephanitis takeyai, from June to October in 2018. A total of 7,560 traps/visual scouting were investigated in 315 points of 105 local sites of seven regions, resulting the nine species, A. diospyri, B. dorsalis, B. minax, B. tsuneonis, C. pomonella, L. botrana, Proeulia sp., S. invicta, and S. takeyai, were not detected. From this study, we established the nationwide monitoring system which can early detect high risk insect pests and secured a bridgehead for monitoring invasive insect pests passing the border.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.31 no.5
• /
• pp.241-252
• /
• 2019

To choose appropriate countermeasures against potential coastal disaster damages caused by a storm surge, it is necessary to estimate the frequency of storm surge heights estimation. As the coastal populations size in the past was small, the tropical cyclone risk model (TCRM) was used to generate 176,689 synthetic typhoons. In simulation, historical paths and central pressures were incorporated as a probability density function. Moreover, to consider the typhoon characteristics that resurfaced or decayed after landfall on the southeast coast of China, incorporated the shift angle of the historical typhoon as a function of the probability density function and applied it as a damping parameter. Thus, the passing rate of typhoons moving from the southeast coast of China to the south coast has improved. The characteristics of the typhoon were analyzed from the historical typhoon information using correlations between the central pressure, maximum wind speed ($V_{max}$) and the maximum wind speed radius ($R_{max}$); it was then applied to synthetic typhoons. The storm surges were calculated using the ADCIRC model, considering both tidal and synthetic typhoons using automated Perl script. The storm surges caused by the probabilistic synthetic typhoons appear similar to the recorded storm surges, therefore this proposed scheme can be applied to the storm surge simulations. Based on these results, extreme values were calculated using the Generalized Extreme Value (GEV) method, and as a result, the 100-year return period storm surge was found to be satisfactory compared with the calculated empirical simulation value. The method proposed in this study can be applied to estimate the frequency of storm surges in coastal areas.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.2
• /
• pp.152-166
• /
• 2022

This study analyzed the causal relationship among operating characteristics of commercial freight vehicles, dangerous driving behaviors, and traffic accident risk. The study applied the existing accident cause and prevention theory to arrive at this relationship. Data related to working characteristics of driver, driving experience, driving ability, driving psychology, vehicle characteristics (size), dangerous driving behavior, and traffic accidents were collected from 303 commercial freight vehicle drivers. Working characteristics and dangerous driving behavior data are based on the driver's digital driving record. The traffic accident data is based on the insurance accident data reflecting actual traffic accidents. First, a structural equation model was built and verified using the model fitness index. Then, the developed model was used to analyze the causal relationship between multiple independent and dependent variables simultaneously. Four dangerous driving behaviors (sudden deceleration, sudden acceleration, sudden passing, and sudden stop) were found to be highly related to traffic accidents. The results further indicate that it is necessary to establish a safety management policy and intensive management for small-sized freight vehicles, drivers with insufficient driving ability, and drivers with dangerous driving behaviors. Such policy and management are expected to reduce traffic accidents effectively.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.2
• /
• pp.118-126
• /
• 2023

In accordance with the increased demand for ocean use, the Marine Spatial Planning system was introduced to rationally allocate ocean space, under which fishing activity protection zones have been designated to protect fishery activities and promote fishery resource protection. However, fishing vessels that mainly sail in fishing activity protection zones are exposed to risk, such that they account for about 70% of marine accidents that occur in Korea, Proper risk management is thus required. This study aims to analyze marine accidents in fishing activities protection zones and port and navigation zones to secure the safety of fishing vessels passing within fishing activity protection zones. To this end, the traffic volume in marine use zones was investigated, and marine accidents were investigated by ship type, accident type, tonnage, accident cause, and loss of life. Analysis determined that most of the marine accidents per unit area of each type occurred in port and navigation zones, but overall most marine accidents occurred in fishing activity protection zones. In particular, it was found that traffic safety management was necessary because many human accidents occurred.