• Journal of Oral Medicine and Pain
• /
• v.30 no.1
• /
• pp.131-140
• /
• 2005

The purpose of this study was to examine the ablation rate of Er: YAG laser irradiation on dentin and enamel and to observe the microscopic structures of cavities formed after ablation of enamel and dentin in using a bur and cavities formed after ablation using laser. Er:YAG laser irradiated at 200 mJ, 250mJ, 300mJ at the frequency of 20Hz, 15Hz. The following results were obtained : 1. The ablation rate of dentin groups at power of 3 W-6 W was about $1.103{\sim}2.639mm^3/sec$ and there were no significant differences between power of 4.5 W$\sim$6 W. 2. The ablation rate of enamel groups at power of 3 W-6 W was about $0.413{\sim}0.969mm^3/sec$ and there were no significant differences between power of 4 W$\sim$6 W. 3. With SEM examination of the cavity surface treated with the conventional high speed bur revealed relatively flat appearance almost covered with a debris like smear layer. 4. With SEM examination of the lased surface of dentin groups revealed no smear layer and no debris and openings of dentinal tubules were clearly opened. But the lased surfaces of the groups over 3 W were irregular and particles were loosely attached on it. 5. With SEM examination of the lased surface of enamel groups revealed severely destructed surface at the 6 W group and melting drop materials at the 3 W group. But the lased surface of 4 W group revealed clearly ablated surface. Therefore when cutting teeth using Er:YAG laser, the lasing power which can make effective ablation rate and minimize the thermal effect could be 3W at dentin and 4W at enamel. But, further studies and additional data collection will be necessary for appropriate lasing condition of Er:YAG laser.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.6
• /
• pp.1185-1194
• /
• 2011

This study was carried out to estimate carbon emission using LCA (Life Cycle Assessment) and to establish LCI (Life Cycle inventory) DB for lettuce production system in protected cultivation. The results of data collection for establishing LCI DB showed that the amount of fertilizer input for 1 kg lettuce production was the highest. The amounts of organic and chemical fertilizer input for 1 kg lettuce production were 7.85E-01 kg and 4.42E-02 kg, respectively. Both inputs of fertilizer and energy accounted for the largest share. The amount of field emission for $CO_2$, $CH_4$ and $N_2O$ for 1 kg lettuce production was 3.23E-02 kg. The result of LCI analysis focused on GHG (Greenhouse gas) showed that the emission value to produce 1 kg of lettuce was 8.65E-01 kg $CO_2$. The emission values of $CH_4$ and $N_2O$ to produce 1 kg of lettuce were 8.59E-03 kg $CH_4$ and 2.90E-04 kg $N_2O$, respectively. Fertilizer production process contributed most to GHG emission. Whereas, the amount of emitted nitrous oxide was the most during lettuce cropping stage due to nitrogen fertilization. When GHG was calculated in $CO_2$-equivalents, the carbon footprint from GHG was 1.14E-+00 kg $CO_2$-eq. $kg^{-1}$. Here, $CO_2$ accounted for 76% of the total GHG emissions from lettuce production system. Methane and nitrous oxide held 16%, 8% of it, respectively. The results of LCIA (Life Cycle Impact assessment) showed that GWP (Global Warming Potential) and POCP (Photochemical Ozon Creation Potential) were 1.14E+00 kg $CO_2$-eq. $kg^{-1}$ and 9.45E-05 kg $C_2H_4$-eq. $kg^{-1}$, respectively. Fertilizer production is the greatest contributor to the environmental impact, followed by energy production and agricultural material production.

• Korean Journal of Remote Sensing
• /
• v.37 no.5_1
• /
• pp.1135-1147
• /
• 2021

In order to geometrically correct high-resolution satellite imagery, the sensor modeling process that restores the geometric relationship between the satellite sensor and the ground surface at the image acquisition time is required. In general, high-resolution satellites provide RPC (Rational Polynomial Coefficient) information, but the vendor-provided RPC includes geometric distortion caused by the position and orientation of the satellite sensor. GCP (Ground Control Point) is generally used to correct the RPC errors. The representative method of acquiring GCP is field survey to obtain accurate ground coordinates. However, it is difficult to find the GCP in the satellite image due to the quality of the image, land cover change, relief displacement, etc. By using image maps acquired from various sensors as reference data, it is possible to automate the collection of GCP through the image matching algorithm. In this study, the RPC of KOMPSAT-3A satellite image was corrected through the extracted matching point using the UAV (Unmanned Aerial Vehichle) imagery. We propose a pre-porocessing method for the extraction of matching points between the UAV imagery and KOMPSAT-3A satellite image. To this end, the characteristics of matching points extracted by independently applying the SURF (Speeded-Up Robust Features) and the phase correlation, which are representative feature-based matching method and area-based matching method, respectively, were compared. The RPC adjustment parameters were calculated using the matching points extracted through each algorithm. In order to verify the performance and usability of the proposed method, it was compared with the GCP-based RPC correction result. The GCP-based method showed an improvement of correction accuracy by 2.14 pixels for the sample and 5.43 pixelsfor the line compared to the vendor-provided RPC. In the proposed method using SURF and phase correlation methods, the accuracy of sample was improved by 0.83 pixels and 1.49 pixels, and that of line wasimproved by 4.81 pixels and 5.19 pixels, respectively, compared to the vendor-provided RPC. Through the experimental results, the proposed method using the UAV imagery presented the possibility as an alternative to the GCP-based method for the RPC correction.

• Journal of Korean Society of Forest Science
• /
• v.109 no.4
• /
• pp.382-389
• /
• 2020

Soil properties in opencast mines are a key factor in reclamation (revegetation) of mining areas. In this study we determined the soil physical and chemical properties of kaolinite tailings, reclaimed areas, and adjacent natural red pine (Pinus densiflora S. et Z.) forests in kaolinite opencast mines in Sancheong-gun, Gyeongsangnam-do. Six sites were chosen for collection of soil samples to determine soil physical and chemical properties at a soil depth of 10 cm. Soil bulk density was significantly higher (P < 0.05) in the kaolinite tailings (1.51 g·cm-3) than in the reclaimed areas (1.19 g·cm-3) and red pine forests (0.93 g·cm-3), whereas air phase in the kaolinite tailings (14.2%) was significantly lower than in the red pine forests (32.6%). Clay content in the red pine forests was significantly higher than in the reclaimed areas (18.7%) or kaolinite tailings (14.8%), whereas soil structural stability index was significantly lower in the reclaimed areas (1.61%) and kaolinite tailings (0.87%) than in the red pine forests (7.75%). Soil pH was significantly higher in the kaolinite tailings (pH 6.68) and reclaimed areas (pH 6.27) than in the red pine forests (pH 5.31). Soil organic carbon and total nitrogen were significantly higher in the red pine forests (C: 36.03 mg·g-1; N: 2.08 mg·g-1) than in the reclaimed areas (C: 5.00 mg·g-1; N: 0.31 mg·g-1) than in the kaolinite tailings (C: 2.12 mg·g-1; N: 0.07 mg g-1). The amount of available phosphorus was not significantly different among the three treatments. The concentration of exchangeable potassium was significantly lower in the kaolinite tailings (0.08 cmolc·kg-1) than in the reclaimed areas (0.21 cmolc·kg-1) and red pine forests (0.30 cmolc·kg-1). These results indicate that, because of high soil bulk density and low soil organic carbon, total nitrogen, available phosphorus, and exchangeable potassium in kaolinite tailings and reclaimed mining areas, soil nutrient management is needed in order to reclaim the vegetation in these type of areas.

• Korean Journal of Environment and Ecology
• /
• v.34 no.6
• /
• pp.558-572
• /
• 2020

The purpose of this study was to classify the types of degraded areas of Mt. Jirisan section in Baekdudaegan and survey the actual condition of each damage type to use it as basic data for the direction of the restoration of damaged areas according to damage type based on the vegetation information of reference ecosystem. The analysis of the Mt. Jirisan section's actual degraded conditions showed that the total number of patches of degraded areas was 57, and the number of patches and size of degraded areas was higher at the low average altitude and gentle slope. Grasslands (deserted lands) and cultivated areas accounted for a high portion of the damage types, indicating that agricultural land use was a major damage factor. The survey on the conditions of 14 degraded areas showed that the types of damage were classified into the grassland, cultivated area, restoration area, logged-off land, and bare ground. The analysis of the degree of disturbance (the ratio of annual and biennial herb, urbanized index, and disturbance index) by each type showed that the simple single-layer vegetation structure mostly composed of the herbaceous and the degree of disturbance were high in the grassland and cultivated land. The double-layer vegetation structure appeared in the restoration area where the pine seedlings were planted, and the inflow of naturalized plants was especially high compared to other degraded areas due to disturbances caused by the restoration project and the nearby hiking trails. Although the inflow of naturalized plants was low because of high altitude in bare ground, the proportion of annual and biennial herb was high, indicating that all surveyed degraded areas were in early succession stages. The stand ordination by type of damage showed the restoration area on the I-axis, cultivated area, grassland, logged-off land, and bare ground in that order, indicating the arrangement by the damage type. Moreover, the stand ordination of the degraded areas and reference ecosystem based on floristic variation showed a clear difference in species composition. This study diagnosed the status of each damage type based on the reference ecosystem information according to the ecological restoration procedure and confirmed the difference in species composition between the diagnosis result and the reference ecosystem. These findings can be useful basic data for establishing the restoration goal and direction in the future.

• MISULJARYO - National Museum of Korea Art Journal
• /
• v.97
• /
• pp.55-68
• /
• 2020

The inscription found on buncheong ware (粉靑沙器, grayish-blue-powdered celadon) provides information on the bowl today, but in the past served as a device for controlling tributary payments (貢納) and the movement of government property (官物). The inscription had to be written or engraved clearly so that it could be recognizable to officials in charge of managing bowls. Such inscriptions offer important clues for contemporary research on buncheong ware. Buncheong Bowl with Stamped Design and Inscription of "Naeja" (內子) (bon 13808) in the collection of the National Museum of Korea bears a distinct inscription compared to other buncheong ware. Commonly, the inscription on buncheong indicated the name of the government office (官司名) to which the vessel belonged or the name of the place (地名) where the vessel was produced. However, the inscription "Naeja" on the buncheong bowl at the National Museum of Korea has no corresponding government office. "Naeja" is in fact a misspelling of Naeja (內資), meaning this bowl belonged to the Naejasi (內資寺, Royal Bureau of Procurement). Although "Naeja" (內子) was a misspelling of the intended Naeja (內資), it was still understood as a reference to the Naejasi since they were homophonic. Recently, buncheong ware with misspelled yet homophonous inscriptions have begun to be excavated in downtown Seoul. Examples including "Naeja" (內子) instead of Naeja (內資) and "Insu" (仁守) instead of Insu (仁壽) have been unearthed from historical sites in Seoul that functioned as consumption sites, meaning they were in fact circulated as government property despite the misspellings (whether accidental or the outcome of ignorance). Such misspelled yet homophonous inscriptions are characterized by the use of simple characters and a few sloppy strokes. Like other buncheong ware bearing the inscriptions of government office names, the bowls with the inscriptions of "Naeja" (內子) and "Insu" (仁守) were discovered at historical sites in Seoul. These misspelled homophonous inscriptions reveal that errors occurred during the process of engraving inscriptions on buncheong ware produced as a tributary payment during the early Joseon Dynasty and that buncheong ware with such errors were still distributed.

• Informatization Policy
• /
• v.30 no.2
• /
• pp.22-45
• /
• 2023

In research on the use of AI-based voice assistant services, problems related to the user's trust and privacy protection arising from the experience of service use are constantly being raised. The purpose of this study was to investigate empirically the effects of individual trust in AI and online privacy concerns on the continued use of AI-based voice assistants, specifically the impact of their interaction. In this study, question items were constructed based on previous studies, with an online survey conducted among 405 respondents. The effect of the user's trust in AI and privacy concerns on the adoption and continuous use intention of AI-based voice assistant services was analyzed using the Heckman selection model. As the main findings of the study, first, AI-based voice assistant service usage behavior was positively influenced by factors that promote technology acceptance, such as perceived usefulness, perceived ease of use, and social influence. Second, trust in AI had no statistically significant effect on AI-based voice assistant service usage behavior but had a positive effect on continuous use intention. Third, the privacy concern level was confirmed to have the effect of suppressing continuous use intention through interaction with trust in AI. These research results suggest the need to strengthen user experience through user opinion collection and action to improve trust in technology and alleviate users' concerns about privacy as governance for realizing digital government. When introducing artificial intelligence-based policy services, it is necessary to disclose transparently the scope of application of artificial intelligence technology through a public deliberation process, and the development of a system that can track and evaluate privacy issues ex-post and an algorithm that considers privacy protection is required.

• Korean Journal of Heritage: History & Science
• /
• v.56 no.3
• /
• pp.76-98
• /
• 2023

The results of analyzing the outfits of male and female characters depicted in the "Hoehonryedocheop" (回婚禮圖帖, Deoksu 6375) held by the National Museum of Korea and estimating its production date of the "Hoehonryedocheop"are as follows. Firstly, an elderly groom is depicted wearing a patterned heukdanryeong (黑團領) with rank badges, a garment commonly donned by government officials in works such as "Jeonanryedo (奠鴈禮圖)" and "Gyobaeryedo (交拜禮圖)". And the old groom in "Heonsuryedo (獻壽禮圖)" "Jeobbindo (接賓圖)" and "Jungroeyeondo (重牢宴圖)" is shown wearing a jarip (purple hat) without a paeyoung (ornamental jewelry strap), accompanied by jade colored robe with a red strap belt. Gireokabeom (雁夫) is observed wearing a jarip (紫笠) adorned with a paeyoung (貝纓) and a patternless heukdanryeong with rank badges. Adult male descendants are depicted wearing dopo (道袍), while guests wear dopo, cheolrik (帖裏), and jikryeong (直領), accompanied by red and blue straps denoting their social status. Jingssi (徵氏), sidong (侍童), and young grandchildren are observed wearing jungchimak(中赤莫). The young servants are wearing jungchimak, and the boys carrying the food have braided their hair and worn sochangu (小氅衣), while adults servants wore jeonrip (氈笠) and sochangui. Performers are seen clad in a sochangui, jeonbok, and a blue sash around their waists. Secondly, the elderly bride is portrayed wearing a keunmeori (ceremonial headdress) and a green wonsam (圓衫) in "Gyobaeryedo," while in "Heonsuyeondo," she is depicted in a blue skirt and a jade colored jeogori (赤古里). Women descendants are shown adorning headdress decorations, such as binyeo(簪), banja(斑子) and pearl daenggi (眞珠唐紒) on their eoyeomeori (於于味, ceremonial headdress). They are further dressed in skirts of navy, red, and jade hues, paired with various-colored jeogori. Additionally, a woman wearing a navy skirt and a green jangot (長衣) is also depicted. The dongnyeo (童女, unmarried women) wear beolsaengmeri (娘子雙髻), headdress) with long binyeo and long dodaik-daenggi (都多益唐只). They wear chilbo-jokduri (七寶簇頭里) and a red skirt with a green hoejang-jeogori (回裝赤古里). Bija (婢子) wears garima (加里亇) on her eoyeomeori and is seen dressed in skirts and jeogori resembling those worn by noble women, albeit with lighter colors, shorter skirt length, and a subdued volume. Ginyeo's attire bears similarities to that of noble women, although with a dress with less vibrant tones and devoid of decorations on the eoyeomeori. Thirdly, based on the main character's jarip, along with the cheolrik and jikryeong worn by the guests, as well as the performances by musicians of the military camp, it is suggested that the main character of the 60th wedding anniversary is connected to the Ministry of Military Affairs or the military camp. Judging by the military band's short-sleeved vest, the silhouettes of the women dress, and the headdresses, it is likely that the "Hoehonryedocheop" was produced between the 1760s and 1780s.

• Journal of Korean Society of Forest Science
• /
• v.112 no.4
• /
• pp.417-425
• /
• 2023

The aim of this study was to derive stem taper equations for Quercus acuta, one of main evergreen broad-leaved tree species found in warm temperate regions, and to prepare a stem volume table using those stem taper equations. A total of 688 individual trees were used in the analysis, which were collected from Jeonnam-do, Gyeongnam-do, and Jeju-do. The stem taper models applied to derive the stem curve pattern were the Max and Burkhart, Kozak, and Lee models. Among the three stem taper models, the best explanation of the stem curve shape of Q. acuta was found to be given by the Kozak model, which showed a fitness index of 0.9583, bias of 0.0352, percentage of estimated standard error of 1.1439, and mean absolute deviation of 0.6751. Thus, the stem taper of Q. acuta was estimated using the Kozak model. Moreover,thestemvolumecalculationwasperforme d by applying the Smalian formula to the diameter and height of each stem interval. In addition, an analysis of variance (ANOVA) was conducted to compare the two existing Q. acuta stem volume tables (2007 and 2010) and the newly created stem volume table (2023). This analysis revealed that the stem volume table constructed in the Wando region in 2007 included about twice as much as the stem volume tables constructed in 2010 and 2023. The stem volume table (2023) developed in this study is not only based on the regional collection range and number of utilized trees but also on a sound scientific basis. Therefore, it can be used at the national level as an official stem volume table for Q. acuta.

• Clean Technology
• /
• v.25 no.4
• /
• pp.283-288
• /
• 2019

Monodisperse microparticles has been particularly enabling for various applications in the encapsulation and delivery of pharmaceutical agents. The microfluidic devices are attractive candidates to produce highly uniform droplets that serve as templates to form monodisperse microparticles. The microfluidic devices that have micro-scale channel allow precise control of the balance between surface tension and viscous forces in two-phase flows. One of its essential abilities is to generate highly monodisperse droplets. In this paper, a microfluidic approach for preparing monodisperse polycaprolactone (PCL) microparticles is presented. The microfluidic devices that have a flow-focusing generator are manufactured by soft-lithography using polydimethylsiloxane (PDMS). The crucial factors in the droplet generation are the controllability of size and monodispersity of the microdroplets. For this, the volumetric flow rates of the dispersed phase of oil solution and the continuous phase of water to generate monodisperse droplets are optimized. As a result, the optimal flow condition for droplet dripping region that is able to generate uniform droplet is found. Furthermore, the droplets containing PCL polymer by solvent evaporation after collection of droplet from device is solidified to generate the microparticle. The particle size can be controlled by tuning the flow rate and the size of the microchannel. The monodispersity of the PCL particles is measured by a coefficient of variation (CV) below 5%.