• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.337-344
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• 2005

A tactile sensor employs a piezoelectric element to detect contact frequency shifts and thereby measure the stiffness or softness of material such as tissue, which allows the sensor to be used in many fields of research for urology, cardiology, gynecology, sports medicine and caner detection and especially for cosmetics and skin care. In this study, reliability of the tactile sensor system was investigated with its manual application to the muscles susceptible to temporomandibular disorders. Stiffness and elasticity of anterior temporalis, masseter and trapezius muscles were calibrated bilaterally from 5 healthy men with an average of 24.5$\pm$0.94 years. The tactile sensor used in this study had a computer-controlled and motor-driven sensor unit which automatically pressed down on the skin surface over the muscles being measured and retracted, thereby providing the hysteresis curve. The slope of the tangent of the hysteresis curve (${\Delta}f/{\Delta}x$) is defined as stiffness of the muscle being measured and the distance between the two parts of the curve as its elasticity. To determine inter-examiner reliability, all the measurements were performed by the two examiners A and B, respectively and the same examination were repeated with an interval of 2 days for intra-examiner reliability. The results from this study demonstrated high reliability in measuring stiffness and elasticity of anterior temporalis, masseter and upper trapezius muscles using a tactile sensor system. It is suggested that the tactile sensor system can be a highly reproducible and effective instrument for quantitative evaluation of the muscle in head and neck region.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.583-597
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• 2014

Fire caused by heater has various causes as many as the types of heater. also, lots of damage of human life and property loss are caused, since annually continuous fire accident by heater in traditional market is frequently occurring. There are not many cases of fire due to heater in most of residential facilities such as general house, apartments, etc., because they are supplied with heating boiler, however the restaurant, store and office of the market, sports center, factory, workplace, etc. still use heater, e.g. oilstove, electric heater, etc., so that they are exposed to fire hazard. Also, when investigating the number of fire due to heater, it was analyzed to occur in order of home boiler, charcoal stove, oilstove, gas heater/stove, electric stove/heater, the number of fire per human life damage was analyzed in order of gas heater/stove, oil heater/stove, electric heater/stove, briquette/coal heater. Also, gas and oil related heater were analyzed to have low frequency, however, with high fire intensity. Therefore, this research aimed at considering more scientific fire inspection and identification approach by reenacting and reviewing fire outbreak possibility caused by combustibles' contact and conductivity under the normal condition and abnormal condition in respect of ignition hazard, i.e. minimum ignition temperature, carbonization degree and heat flux along with it, due to oilstove and electric stove, which are still frequently used in public use facility, traditional market, and, of which actual fire occurrence is the most frequent. As the result of reenact test, ignition hazard appeared very small, as long as enough heat storage condition is not made in both test objects(oilstove/electric stove), however carbonization condition was analyzed to be proceeded per each part respectively. Eventually, transition to fire is the ignition due to heat storage, so that it was analyzed to ignite when minimum heat storage temperature condition of fire place is over $500^{\circ}C$. Particularly, in case of quartz pipe, the heating element of electric stove, it is rapidly heated over the temperature of $600^{\circ}C$ within the shortest time(10sec), so that the heat flux of this appears 6.26kW/m2, which was analyzed to result in damage of thermal PVC cable and second-degree burn in human body. Also, the researcher recognized that the temperature change along with Geometric View Factor and Fire Load, which display decrease of heat, are also important variables to be considered, along with distance change besides temperature condition. Therefore, the researcher considers that a manual of careful fire inspection and identification on this is necessary, also, expects that scientific and rational efforts of this research can contribute to establish manual composition and theoretical basis on henceforth fire inspection and identification.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.518-527
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• 2014

Our society is changed and diversified rapidly and such tendency is accelerated day after day and has made a lot of problems in the many fields. The important thing we have to recognize is such tendency has a bad effect recently on the safety system in Korea. So it is time to enhance the national safety system and moreover recently Sewol-ho(passenger ship) went down in the sea, it made people remind the importance of national safety system. With this incident, Korean government decided to establish the national safety communication network against the disaster. At this time, I will propose several ideas about the national safety communication network. 1. It must to be established an unified network to contact people who is on a disaster site anytime and anywhere. This is most important element on all disaster sites. 2. PS-LTE technology must to be adopted to the network because it has many advantages including various multimedia services compared to the TETRA in the past. 3. 700MHz is the most efficient band for the network because it has wide cell sites coverage compared to 1.8GHz. 4. Satellite communication system is needed to the network for back-up. 5. It will be effective to adopt Social Media to the communication network system like a Twitter or Facebook for sharing many kinds of information and notifying people of warning message. 6. It can make the network more useful to introduce the latest technology like a sensor network. And Korean government has to improve the system related to the disaster including law and operating organization.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.111-121
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• 2010

Purpose: This 3D-FEA study was performed to investigate the influence of marginal bone loss pattern around the implant to the stress distribution. Material and methods: From the right second premolar to the right second molar of the mandible was modeled according to the CT data of a dentate patient. Teeth were removed and an implant ($\Phi\;4.0{\times}10.0mm$) was placed in the first molar area. Twelve bone models were created; Studied bone loss conditions were horizontal bone loss and vertical bone loss, assumed bone loss patterns during biologic width formation, and pathologic vertical bone loss with or without cortification. Axial, buccolingual, and oblique force was applied independently to the center of the implant crown. The Maximum von Mises stress value and stress contour was observed and von Mises stresses at the measuring points were recorded. Results: The stress distribution patterns were similar in the non-resorption and horizontal resorption models, but differed from those in the vertical resorption models. Models assuming biologic width formation showed altered stress distribution, and weak bone to implant at the implant neck area seams accelerates stress generation. In case of vertical bone resorption, contact of cortical bone to the implant may positively affect the stress distribution.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.1
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• pp.69-81
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• 2015

Under the premise that parks have been a performing field of welfare ideology that benefits the citizen from the past, the present study began with a basic question on what substance a park has and how it has worked. Therefore, this study tried to find out the theoretic background that can explain the roles of a park as an instrument for welfare, of which topic is currently being discussed, and examine how the ideology in the debate regarding welfare characteristics of parks are differentiated from those of social welfare. In addition, this study divided the process of development of parks defined by Galen Cranz in an attempt to view how welfare benefits offered by parks have changed in their development and looked into the roles and types of welfare functions that parks provided to the citizens under a certain social situation by period. Furthermore, the characteristics and development of the ideology underlying a welfare park were examined by function and element in its progression. The results of this study are as follows. The functions that parks have performed so far can be classified into three categories. First, they have a remedial function. Parks have given direct services to 'the socially disadvantaged' such as relief, fostering, and rehabilitation. Second, parks have played a preventive function. They aim to reinforce the functions of individual, family, group, and community. Third, they have exerted a developmental function. They function to promote change of society in a way for it to contribute to social development. Looking into the roles and functions of parks from the perspective of their beneficiary class and benefits, the following were discovered. First, the beneficiaries of welfare characteristics in parks have expanded to the general public from the poor class, and the benefits of parks have spread into the public including the underprivileged in a real sense. Second, the significance of welfare characteristics in parks has also changed from literal benefits to caring for basic human rights. Third, the purpose of welfare characteristics in parks has changed from providing minimal conditions to optimal conditions. At its beginning, the ideology of welfare in parks remained ideal, confining itself to their idealistic characteristics; but as time went on, they created several social benefits in response to various social demands, developing into a field where welfare ideology manifests and is realized in an active manner. Furthermore, it was witnessed that the parks and welfare of the present times are standing at the point of contact for participation and universal well-being. The present study reconsidered the meaning and value of parks from perspective of them as a provider of welfare benefits as well as examined how the welfare ideology of parks is connected to practice. By doing so, this study discovered the various roles, values, and ideology that parks should bear in the future. Therefore, this study is expected to be a good example for future research related to the topic.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.3
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• pp.157-167
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• 2021

Lead (Pb) is one of the key trace elements, exhibiting a peculiar partitioning behavior into silicate melts in contact with minerals. Partitioning behaviors of Pb between silicate mineral and melt have been known to depend on melt composition and thus, the atomic structures of corresponding silicate liquids. Despite the importance, detailed structural studies of Pb-bearing silicate melts are still lacking due to experimental difficulties. Here, we explored the effect of lead content on the atomic structures, particularly the evolution of silicate networks in Pb-bearing sodium metasilicate ([(PbO)_x(Na₂O)_1-x]·SiO₂) glasses as a model system for trace metal bearing natural silicate melts, using ²⁹Si solid-state nuclear magnetic resonance (NMR) spectroscopy. As the PbO content increases, the ²⁹Si peak widths increase, and the maximum peak positions shift from -76.2, -77.8, -80.3, -81.5, -84.6, to -87.7 ppm with increasing PbO contents of 0, 0.25, 0.5, 0.67, 0.86, and 1, respectively. The ²⁹Si MAS NMR spectra for the glasses were simulated with Gaussian functions for Qⁿ species (SiO₄ tetrahedra with n BOs) for providing quantitative resolution. The simulation results reveal the evolution of each Qⁿ species with varying PbO content. Na-endmember Na₂SiO₃ glass consists of predominant Q² species together with equal proportions of Q¹ and Q³. As Pb replaces Na, the fraction of Q² species tends to decrease, while those for Q¹ and Q³ species increase indicating an increase in disproportionation among Qⁿ species. Simulation results on the ²⁹Si NMR spectrum showed increases in structural disorder and chemical disorder as evidenced by an increase in disproportionation factor with an increase in average cation field strengths of the network modifying cations. Changes in the topological and configurational disorder of the model silicate melt by Pb imply an intrinsic origin of macroscopic properties such as element partitioning behavior.

• Journal of Environmental Impact Assessment
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• v.28 no.2
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• pp.152-168
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• 2019

The element arsenic, which is abundant in the Earth's crust, is used for various industrial purposes including materials for disease treatment and household goods. Various human activities, such as the disposal of soil waste, metal mining and smelting, and combustion of fossil fuels, have caused the pollution of the environment with arsenic. Recently, guidelines for arsenic in rice have been adopted by the Korean ministry of food and drug safety to prevent health risks based on rice consumption. Because of the exposure to arsenic and its accumulation in the human body through various channels, such as air inhalation, skin contact, ingestion of drinking water, and food consumption, integrated multimedia risk assessment is required to adopt appropriate risk management policies. Therefore, integrated human health risk assessment was carried out in this study using integrated exposure assessment based on multimedia (e.g., air, water, and soil) and multi-route (e.g., oral, inhalation, and dermal) scenarios. The results show that oral uptake via drinking water is the most common pathway of arsenic into the human body, accounting for 57%-96% of the total arsenic exposure. Among various age groups, the highest exposures to arsenic were observed in infants because the body weight of infants is low and the surface areas of infant bodies are large. Based on the results of the exposure assessment, the cancer and non-cancer risks were calculated. The cancer risk for CTE and RME is in the range of 2.3E-05 to 6.7E-05 and thus is negligible because it does not exceed the cancer probability of 1.0E-04 for all age groups. On the other hand, the cancer risk for RME varies from 6.4E-05 to 1.8E-04 and from 1.3E-04 to 1.8E-04 for infants and preschool children, exceeding the excess cancer risk of 1.0E-04. The non-cancer risks range from 5.4E-02 to 1.9E-01 and from 1.5E-01 to 6.8E-01, respectively. They do not exceed the hazard index 1 for all scenarios and all ages.