• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.130-130
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• 2021

The increasing effect of urbanization has been more apparent through flooding and downstream water quality especially from heavy rainfalls. In response, stormwater runoff management solutions have focused on runoff volume reduction and treatment through infiltration. However, there are areas with low infiltration soils or are experiencing more dry days and even drought. In this study, a lab-scale infiltration system was used to compare the applicability of two types of soil as base layer in gravel-filled infiltration systems with emphasis on runoff capture and suspended solids removal. The two types of soils used were sandy soil representing a high infiltration system and clayey soil representing a low infiltration system. Findings showed that infiltration rates increased with the water depth above the gravel-soil interface indicating that the available depth for water storage affects this parameter. Runoff capture in the high infiltration system is more affected by rainfall depth and inflow rates as compared to that in the low infiltration system. Based on runoff capture and pollutant removal analysis, a media depth of at least 0.4 m for high infiltration systems and 1 m for low infiltration systems is required to capture and treat a 10-mm rainfall in Korea. A maximum infiltration rate of 200 mm/h was also found to be ideal to provide enough retention time for pollutant removal. Moreover, it was revealed that low infiltration systems are more susceptible to horizontal flows and that the length of the structure may be more critical that the depth in this condition.

• Membrane and Water Treatment
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• v.14 no.4
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• pp.155-162
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• 2023

Global climate change and urbanization have various demerits, such as water pollution, flood damage, and deterioration of water circulation. Thus, attention is drawn to Nature-based Solution (NbS) that solve environmental problems in ways that imitate nature. Among the NbS, urban wetlands are facilities that perform functions, such as removing pollutants from a city, improving water circulation, and providing ecological habitats, by strengthening original natural wetland pillars. Frequent monitoring and maintenance are essential for urban wetlands to maintain their performance; therefore, there is a need to apply the Internet of Things (IoT) technology to wetland monitoring. Therefore, in this study, we attempted to develop a real-time wetland monitoring device and interface. Temperature, water temperature, humidity, soil humidity, PM1, PM2.5, and PM10 were measured, and the measurements were taken at 10-minute intervals for three days in both indoor and wetland. Sensors suitable for conditions that needed to be measured and an Arduino MEGA 2560 were connected to enable sensing, and communication modules were connected to transmit data to real-time databases. The transmitted data were displayed on a developed web page. The data measured to verify the monitoring device were compared with data from the Korea meteorological administration and the Korea environment corporation, and the output and upward or downward trend were similar. Moreover, findings from a related patent search indicated that there are a minimal number of instances where information and communication technology (ICT) has been applied in wetland contexts. Hence, it is essential to consider further research, development, and implementation of ICT to address this gap. The results of this study could be the basis for time-series data analysis research using automation, machine learning, or deep learning in urban wetland maintenance.

• International Journal of Computer Science & Network Security
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• v.23 no.12
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• pp.225-234
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• 2023

In this era of information and communication technology (ICT), tremendous improvements have been witnessed in our daily lives. The impact of these technologies is subjective and negative or positive. For instance, ICT has brought a lot of ease and versatility in our lifestyles, on the other hand, its excessive use brings around issues related to physical and mental health etc. In this study, we are bridging these both aspects by proposing the idea of AI based mental healthcare (AIMS). In this regard, we aim to provide a platform where the patient can register to the system and take consultancy by providing their assessment by means of a chatbot. The chatbot will send the gathered information to the machine learning block. The machine learning model is already trained and predicts whether the patient needs a treatment by classifying him/her based on the assessment. This information is provided to the mental health practitioner (doctor, psychologist, psychiatrist, or therapist) as clinical decision support. Eventually, the practitioner will provide his/her suggestions to the patient via the proposed system. Additionally, the proposed system prioritizes care, support, privacy, and patient autonomy, all while using a friendly chatbot interface. By using technology like natural language processing and machine learning, the system can predict a patient's condition and recommend the right professional for further help, including in-person appointments if necessary. This not only raises awareness about mental health but also makes it easier for patients to start therapy.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.80-88
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• 2003

Object The purpose of this study were to evaluate the microtensile bond strength of resin fiber reinforced post to radicular dentin using resin cement according to various dentin surface treatment and to observe the inter face between post and root dentin under SEM Material and Method A total 16 extracted human single rooted teeth were used. A lingual access was made using a #245 carbide bur in a high-speed handpiece with copious air water spray. The post space was mechanically enlarged using H-file(up to #60) and Gates Glidden bures(#3). This was followed by refining of the canal space using the calbrating drill set provided in ER Dentinpost(GEBR, BRASSELER GmbH&Co. KG). The 16 teeth were randomly distributed into 4 group of 4 teeth. Group 1 teeth had their post space prepared using 10% phosphoric acid as root canal surface treatment agent during 20s. The canal was then rinsed with saline and dried with paper point. Group 2 teeth had their post space prepared using 3% NaOCl as root canal surface treatment agent during 30min. The canal was then rinsed with saline and dried with paper point. Group 3 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. The canal was then rinsed with saline and dried with paper point. Group 4 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. After rinsing with saline, the canal was rinced 10m1 of 3% NaOCl for 30min. After drying with paper point, the post(ER Dentinpost, GEBR, BRASSELER GmbH&Co. KG) was placed in the treated canals using resin cement. Once the canal was filled with resin cement(Super bond C&B sunmedical co. Ltd.), a lentulo was inserted to the depth of the canal to ensure proper coating of the root canal wall. After 24 hours, acrylic resin blocks($10{\cdot}10{\cdot}50mm$) were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strengths for each stick was measured with Microtensile Tester. Failure pattern of the specimen at the interface between post and dentin were observed under SEM. Results 1. Tensile bond strengths(meen{\pm}SD$) ) were expressed with ascending order as follows group 4, $12.52{\pm}6.60$ ; group 1, $7.63{\pm}5.83$ ; group 2, $4.13{\pm}2.31$ ; group 3, $3.31{\pm}1.44$. 2. Tensile bond strengths of Group 4 treated with 17% EDTA +3%NaOCl were significant higher than those of group 1, 2 and 3 (p<0.05). 3. Tensile bond strengths of Group 1 treated with 10% phosphoric acid were significant higher than those of group 2 (p<0.05). Tensile bond strengths of Group 4 treated with 17% EDTA +3% NaOCl was significant higher than those of other groups.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.204-214
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• 2007

The aim of this study was to investigate whether differences in surface treatment prior to repair influenced the seal of a resin fissure sealant placed on the occlusal surfaces of permanent molar teeth. One hundred and twenty extracted human molars were selected and a light curing sealant was placed on their occlusal surface following cleaning by prophylaxis and acid etching. The teeth were deliberately damaged, and then stored in artificial saliva for four weeks. Sixty teeth with the desired morphology of sealant failure were randomly divided into four groups where one group was treated with only etching agent, another by only air-abrasion, another by applying an etching agent followed by a bonding agent, and the last by air-abrasion followed by a bonding agent each. After sealant application, the samples were thermocycled and the degree of microleakage was determined. The results were as follows : 1. In the sealant/sealant interface group 2(0.22), 4(0.23) using air-abrasion showed a significantly lower microleakage score than group 1(0.38), 3(0.35) using an etching agent(p<0.05). There were no statistically significant differences(p>0.05) between groups 1, 2 and groups 3, 4. 2. In the sealant/tooth interface, group 3(0.20), 4(0.20) which used a bonding agent showed a significantly lower microleakage score than group 1(0.35), 2(0.40) (p<0.05). There were no statistically significant differences(p>0.05) between groups 1, 3 and groups 2, 4. 3. In SEM examination, while sealant surfaces treated with etching did not result in highly rough surfaces, those treated with air-abrasion did show rough surfaces.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.310-321
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• 1999

In this in vitro study, confocal laser scanning microscopic morphology of dentin-resin interface and its relationship to shear bond strength were investigated after the exposed dentin surfaces were treated with 3 different kinds of dentin adhesive systems[three-step; Scotchbond Multi-Purpose Plus(SMPP), self-priming bonding resin; Single Bond(SB), self-etching primer; Clearfil Liner Bond 2(LB2)]. 52 extracted human molar teeth without caries and/or restorations. The experimental teeth were randomly divided into three groups of seventeen teeth each. In five teeth of each group, class V cavities(depth: 1.5mm) with 900 cavosurface angles were prepared at the cementoenamel junction on buccal and lingual surfaces. Bonding resins of each dentin adhesive system were mixed with rhodamine B. Primer of SMPP was mixed with fluorescein. In group 1. the exposed dentin was conditioned with etchant, applied with above primer and bonding resin of SMPP. In group 2, with etchant and self-priming bonding agent of SB. In group 3, with self-etching primer and bonding agent of LB2. After treatment with dentin adhesive systems, composite resin were applied and photocured. The experimental teeth were cut longitudinally through the center line of restoration and grounded so that about $90{\mu}m$-thick wafers of buccolingually orientated dentin were obtained. And, $70{\sim}80{\mu}m$-thick wafers sectioned horizontally, thus presenting a dentinal tubules at 900 to the cut surface of a remaining tooth, were obtained. Primer of SMPP mixed with rhodamine B was applied to these wafers. Confocal laser scanning microscopic investigations of these wafers were done within of 24 hours after treatment. To measure shear bond strength, the remaining twelve teeth of each group were grounded horizontally below the dentinoenamel junction, so that no enamel remained. After applying dentin adhesive systems on the dentin surface, composite was applied in the shape of cylinder. The cylinder was 5mm in diameter, and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. It was concluded as follows ; 1. Hybrid layer of SMPP(mean: $4.56{\mu}m$) was thicker than that of any other groups. This value was not statistically significant thicker than that of SB(mean: $3.41{\mu}m$, p>0.05), and significant thicker than that of LB2(mean: $1.56{\mu}m$, p<0.05). There was a statistical difference between SB and LB2(p<0.05). 2. Although there were variations in the length of resin tag even in a sample, and in a group, most samples in SMPP and SB showed resin tags extending above $20{\mu}m$. But samples in LB2 showed resin tags of $10{\mu}m$ at best. 3. Besides primer's infiltration into demineralized peritubular dentin and dentinal tubules, fluorophore of primer was detected in the lateral branches of dentinal tubules. 4. All groups demonstrated statistically significant differences from one another(p<0.05), with shear bond strengths given in descending order as follows: SMPP(18.3MPa), SB(16.0MPa) and LB2(12.4MPa). 5. LB2 having thinnest hybrid layer($1.56{\mu}m$) showed the lowest shear bond strength(12.4MPa).

• Phonetics and Speech Sciences
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• v.11 no.1
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• pp.51-61
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• 2019

The purpose of this study was to develop a smartphone based voice therapy program for patients with voice disorders. Contents of voice therapy were collected through analysis of mobile contents related to voice therapy in Korea, experts and users' demand survey, and the program was developed using Android Studio. Content needed for voice therapy was collected through analysis of mobile contents related to voice therapy. The user satisfaction evaluation for application was conducted for five patient with functional voice disorders. The results showed that the mobile contents related to voice therapy in Korea were mostly related to breathing, followed by voice and singing, but only 13 applications were practically practiced for voice therapy. Expert and user demand surveys showed that the patients and therapists both had a high need for content that could provide voice training in places other than the treatment room. Based on this analysis, 'Home Voice Trainer', an smartphone based voice therapy program, was developed. Home Voice Trainer is an application for voice therapy and management based on Android smartphones. It is designed to train voice therapy activities at home that have been trained offline. In addition, the records of voice training of patients were managed online so that patients can maintain voice improvement through continuous voice consulting even after the end of voice therapy. User evaluations show that patients are satisfied with the difficulty and content of voice therapy programs provided by home voice trainers, but lack of a portion of user interface, such as the portion of home button and interface between screens. Further study suggests the clinical application of home voice trainer to the patients with voice disorders. It is expected that the development study and the clinical application of smart contents related to voice therapy will be actively conducted.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.41-56
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• 2008

The methods of surface modification of commercial implants were various according to the manufacturer. Surface modification of implant may produce diverse physical and chemical surface characteristics resulted from the treatment method and treatment condition. As a result, the bone response might be different. Even though surface modified implants have been used clinically, most researches are focusing on the bone response of surface modified implants comparing to machined implants rather than surface modified commercial implants. This study compare and analyze bone responses of 4 surface modified commercial implants with different shapes and surfaces. Eighty surface modified commercial implants with 4 different surface characteristics were installed in the tibia of white Newzealand rabbits. Biomechanical stability tests and histomorphometric evaluation were done. The results were as follows: 1. Surface modified commercial implants showed stable osseointegration at 6 weeks after installation. 2. Histomorphometric evaluation showed that there was no significant differences in bone to implant contact among 4 different commercial titanium implants. In comparing the implants with different shape the measurement of bone growth in subcortical area would be more reliable than entire bone to implant contact length. 3. Resonance Frequency Analysis showed that there was no significant differences among 4 types of implants, even though they were significantly different in installation. 4. There was significant differences in interfacial shear strength among 4 type of implants. 5. It is difficult to observe accurate bone to implant interface using Micro-CT. However, it is possible to measure the entire contact length of the implant to the bone.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.272-281
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• 2020

Environmental agents, including viral and bacterial infectious agents, are involved in the alteration of physicochemical and biological parameters in the nasal epithelium. Hyaluronan (HA) has an important role in the regulation of tissue healing properties. High molecular weight HA (HMW-HA) shows greater anti-inflammatory responses than medium molecular weight HA (MMW-HA) and low molecular weight HA (LMW-HA). We investigated the effect of HMW-HA, MMW-HA and LMW-HA on the regulation of physicochemical and biological parameters in an "in vitro" model that might mimic viral infections of the nasal epithelium. Human nasal epithelial cell line RPMI2650 was stimulated with double-stranded RNA (dsRNA) Poly(I:C) for 5 days in air-liquid-interface (ALI) culture (3D model of airway tissue). dsRNA Poly(I:C) treatment significantly decreased transepithelial electrical resistance (TEER) in the stratified nasal epithelium of RPMI2650 and increased pH values, rheological parameters (elastic G' and viscous G''), and Muc5AC and Muc5B production in the apical wash of ALI culture of RPMI2650 in comparison to untreated cells. RPMI2650 treated with dsRNA Poly(I:C) in the presence of HMW-HA showed lower pH values, Muc5AC and Muc5B production, and rheological parameters, as well as increased TEER values in ALI culture, compared to cells treated with Poly(I:C) alone or pretreated with LMW-HA and MMW-HA. Our 3D "in vitro" model of epithelium suggests that HMW-HA might be a coadjuvant in the pharmacological treatment of viral infections, allowing for the control of some physicochemical and biological properties affecting the epithelial barrier of the nose during infection.

• Journal of the Korean Society for Heat Treatment
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• v.19 no.1
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• pp.10-19
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• 2006

Microstructure and morphology of precipitates in $Ni_3Al$- and TiAl-based intermetallics containing carbon have been investigated in terms of transmission electron microscopy(TEM). In an $L1_2$-ordered $Ni_3Al$ alloy with 4 mol.% of chromium and 0.2~3.0 mol.% of carbon, fine octahedral precipitates of $M_{23}C_6$ type carbide were formed in the matrix by aging at temperatures around 973 K after solution annealing at 1423 K. TEM examination revealed that the $M_{23}C_6$ phase and the matrix lattices have a cube-cube orientation relationship and keep partial atomic matching at the {111} interface. After prolonged aging or by aging at higher temperatures, the $M_{23}C_6$ precipitates then adopt a rod-like morphology elongated parallel to the <100> directions. In the $L1_0$-ordered TiAl containing 0.1~2.0 mol.% carbon, TEM observations revealed that needle-like precipitates, which lie only in one direction parallel to the [001] axis of the $L1_0$ matrix, appear in the matrix and preferentially at dislocations. Selected area electron diffraction(SAED) patterns analyses have shown that the needle-shaped precipitate is $Ti_3AlC$ of perovskite type. The orientation relationship between the $Ti_3AlC$ and the $L1_0$ matrix is found to be $(001)_{Ti3AlC}//(001)_{L10\;matrix}$ and $[010]_{Ti3AlC}//[010]_{L10\;matrix}$. By aging at higher temperatures or for longer period at 1073 K, plate-like precipitates of $Ti_2AlC$ with a hexagonal structure are formed on the {111} planes of the $L1_0$ matrix. The orientation relationship between the $Ti_2AlC$ and the $L1_0$ matrix is $(0001)_{Ti2AlC}//(111)_{L10\;matrix}$ and $_{Ti2AlC}//_{L10\;matrix}$.