• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.271-274
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• 1999

In this paper, we studied the matrix type Powder AC Electroluminescence using ZnS:Cu,Cl Phosphor. Previously, Powder AC EL was used in Backlighting of LCD. Rescently, organic Thin Film EL was rapidly developed because of high Luminescence and low applied voltage. But Powder AC EL has Superior features that include sheet like flexibility thickness, low weight, self-emission, a wide viewing angle and a fast response time. We tried to change of phosphor thickness and binder mixture rate in order to obtain the good condition of powder AC EL and we obtained the very low breakdown voltage that was just 15V. Till now, we measured the current-voltage(V-I), luminance-voltage(V-L), Luminance-current (L-I), color coordinate (CIE), and phosphor Intensity of variable thickness. In experiment result, the devices has the luminance of 840 cd/$m^2$ and improved color coordinate, x=0.1557, y=0.2145, using a 10kHz drive frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.209-216
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• 2015

It is difficult to detect, track and intercept ballistic missile because of its high speed and short flight time from launching to target area. In order to increase the success rate of a ballistic missile interceptor, it is important to track the flight trajectory for a long time after the detection in the early launch. Radar Cross Section(RCS) of the target is important when the target to be detected by the radar, and the difference between the RCS value greatly changes depending on the viewing direction during the flight missile trajectory. In this paper, it is assumed that a ballistic missile is launched at east coast of North Korea, observe that missile by a land based radar and sea deployed radar. And it is analyzed and compared that RCS difference of ballistic missile.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.341-350
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• 2019

Garlic is one of the most popular seasoning bulb vegetables in Korea and is the most commonly used food ingredient. However, the cultivation areas are decreasing every year as the price drops due to imported garlic, and labor is insufficient to produce garlic by conventional methods. Cultivation requires various tasks until garlic is harvested. Seeding is one of the important and laborious tasks; thus, mechanization is necessary. When seeding garlic, the sprout should face upwards; otherwise, it may rot or produce poor quality garlic. This study investigated the extent of growth of northern- and southern-type garlic in eight different positions. The results show when the roots were not planted properly, the stems were weak, and the garlic bulbs were small. A simple garlic planter was manufactured with a crank-press mechanism to plant garlic in an upright position. Using this machine, a three-fold experiment was carried out with 100 strips of garlic. The test results showed that 99.4% of the planted garlic strips were positioned upright or close to being upright, and 0.6% failed to take root. An image processing algorithm was developed to locate the root part of the garlic, and the result showed a success rate of 81%. A future study will develop an automatic garlic upright planting system with a viewing system.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.270-275
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• 2023

The government has defined domestic violence as one of the four major social evils and tried to prepare laws and systems to prevent it. Nevertheless, domestic violence has emerged as a serious social issue, and compare to the number of domestic violence cases that are constantly increasing, the report rate of domestic violence is significantly lower. This suggests the need to improve citizens' perception of domestic violence as the issue to solve it together in society, not as a private matter at home. Most of existing contents for preventing domestic violence and improving awareness are simple viewing forms of video contents, which have little effect on recognition. We aim to confirm the possibility of improving social awareness about domestic violence by producing Virtual Reality (VR) contents that have great features of user's immersion and empathy. In this VR content, the user can interact with various objects in the virtual reality of domestic violence and directly or indirectly experience the victim's position. Users who view the violent environment from the victim's point of view can have a subjective empathy for the problem, which is expected to induce more active awareness about domestic violence.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.381-382
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• 2023

Frequent accidents occur when workers at construction sites leave the safety zone, and particularly in the past 5 years, 9 fatal accidents occurred at the Korea Railroad Corporation due to train accidents on other tracks during track work. With the Severe Accident Punishment Act taking effect in January 2022, it is a priority to secure a safe work environment for workers at industrial (construction) sites. Therefore, there is a need to manage workers' departure from the safety zone (construction zone) and to facilitate communication within the construction zone. In this study, a mobile edge computing CCTV system is proposed that uses geofencing to determine whether workers are working in the danger zone, which can judge and respond in real-time to the ever-changing field environment. The proposed system is mobile and flexible, rather than server-based fixed CCTV. However, since it is designed mainly based on images, it has limitations in recognition rate depending on the environment such as distance, viewing angle, and illumination. As a way to compensate for this, it is required to develop more reliable equipment by combining technologies such as LiDAR and Radar.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.149-157
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• 2023

The propagation speed of a circumstellar pattern revealed in the plane of the sky is often assumed to represent the expansion speed of the wind matter ejected from a post-main-sequence star at the center. We point out that the often-adopted isotropic wind assumption and the binary hypothesis as the underlying origin for the circumstellar pattern in the shape of multilayered shells are, however, mutually incompatible. We revisit the hydrodynamic models for spiral-shell patterns induced by the orbital motion of a hypothesized binary, of which one star is losing mass at a high rate. The distributions of transverse wind velocities as a function of position angle in the plane of the sky are explored along viewing directions. The variation of the transverse wind velocity is as large as half the average wind velocity over the entire three dimensional domain in the simulated models investigated in this work. The directional dependence of the wind velocity is indicative of the overall morphology of the circumstellar material, implying that kinematic information is an important ingredient in modeling the snapshot monitoring (often in the optical and near-infrared) or the spectral imaging observations for molecular line emissions.

• Journal of Korean Library and Information Science Society
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• v.49 no.1
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• pp.47-75
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• 2018

The objective of this study is to investigate the current usage and Satisfaction Levels of modern literature services provided by the National Library of Korea, and explore the strategies to promote the use of the modern literature service. The result show that the usage rate of users for the modern literature service is very low, and the Satisfaction Level of the experienced users are found to be normal. Therefore, in order to increase the utilization rate and the Satisfaction Level, first, it is required for active promotion of current modern literature services. Second, the public relations of exhibitions and viewing information are provided direct access to users of the modern literary materials, so various types of exhibitions and events are necessary. Third, although respondents said that library homepage, portal site, and SNS are effective public relations methods, in the case of less-educated and seniors, they prefer public relations through offline media. Therefore, deeper theoretical considerations are necessary in order to select affordable public relations media.

• Korean journal of applied entomology
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• v.4
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• pp.7-10
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• 1965

In an experiment to evaluate the various aspects of symptom of witches' broom of jujube tree with two different kinds of scions, taken from diseased plant and stem- grafted upon sound stocks-one cut before wintering(stored in cellar), the other after wintering, it was observed that the disease rate of those cut before wintering(Nov.) was $\98\%$ whereas those cut after wintering(March) showed much lower rate, $3\%$ initially and gradually increased up to $39\%$. In another experiment of diseased bud grafted into healthy seedling, the finding made in the following year was that 14 stocks(only one of which salt union by callusing) were infected out of the given 23- in the initial stage only 4, yet gradually increased to the number of 14. The shoots from the ground portion of the diseased stock were in general more quickly subjected to the disease than the others. Under natural condition, the diseased trees develop at first seemingly the same leaves as healthy ones; it is not until the branches and loaves grow to a considerable degree that the symptom appears. Once appearing, tile disease grows and the symptom continues to appear as late as in Sept. and early Oct., causing tile plant to develop the extraordinary branches and leaves of extremely reduced size, the typical symptom of witches' broom. Such phenomenon can be observed in the experiments of the foregoing paragraphs. And the suckers and roots of diseased plant are bound to be infected, it was found out with no exception. Viewing from the results of the above experiments and observation, it is believed that the low temperature during winter causes the virus in the above-ground portion of diseased plant to diminish or inactivated, and subsequently the virus in the roots moves up or multiply in the sprouting season.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.155-163
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• 1986

From Nov. 1983 through Feb. 1986, 35 patients of uterine cervical cancer were treated by external radiation therapy and intracavitary radiation therapy using Fletcher-Suit-Delclos applicator. Age of the patients ranged from 32 to 70 years (median age: 53 years). All patients had follow up from 9 to 34 months and median follow up of 20 months.4 patients were in stage I, 25 were in stage II, 5 were in stage III and 1 was in stage IV. Overall regression rate was $80\%$ and uncorrected actuarial 2 year survival rate was $88\%$. The incindence of rectal complications were analyzed. There was no rectal complication in the patients who received less than 7000 rad maximal rectal dose, but 2 out of 17 patients who received more than 7000 rad developed moderate degree (grade 2) of rectal complication. In viewing of our results, Fletcher-Suit-Delclos applicator (3M) seemed to be an appropriate instrument for intracaviary radiation therapy in the patients of uterine cervical cancer.

• Korean Journal of Optics and Photonics
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• v.29 no.6
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• pp.262-267
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• 2018

In this paper, we designed a new antireflective film to improve the optical efficiency of organic light-emitting diode displays (OLEDs). The reflection characteristics in the normal and side viewing directions of OLEDs with the antireflective film were calculated, depending on the degree of polarization and transmittance of the currently used polarizer when used in the antireflective film of an OLED. The results showed that when the polarization degree of the commercial polarizer (99.990~99.995%) is lowered to 99.900%, the average reflectance of the antireflective film is increased by about 0.1% (2.5% in terms of rate of increase) which is difficult to notice with the human eye, while the transmittance is increased by 1.63~3.34% (4.2~8.2% in terms of rate of increase). This study provides an optimal design for high-light-efficiency OLEDs with good antireflection properties.