• Restorative Dentistry and Endodontics
• /
• v.25 no.3
• /
• pp.459-473
• /
• 2000

Dental caries is the most common disease in the maxillofacial area. There are many factors contributing to its development, but complete understanding and prevention is not fully known. Since the structure of the coronal and root portion of the tooth is different, the remineralization and demineralization process is also known to be different. In this study, by using a partially saturated buffer solution, we created artificial enamel and dentin caries and evaluated mineral loss. A remineralization solution with four different degrees of saturation (degree of saturation ; group 1, 0.268, group 2, 0.309, group 3, 0.339, group 4, 0.390, PH 4.3, F-2ppm) was used on a demineralized specimen. The mineral precipitating quantity and depth was evaluated by using microradiography. Using an atomic force microscope (AFM), hydroxyapatite crystals of normal, demineralized, and remineralized enamel and dentin were evaluated. The results were as follows: 1. As the degree of saturation of the remineralizing solution increased, the mineral precipitation in the enamel was increased. In group 4, mineral precipitation was limited near the surface. 2. As the degree of saturation of the remineralizing solution increased, the mineral precipitation in the dentin was decreased and it occurred in a deeper portion. In group 4, however, mineral precipitation occurred on the surface and its quantity increased. 3. There was a statistically significant interaction between enamel and dentin mineral content changes on specimens treated with remineralization and demineralization solution (demineralization r=0.44, remineralization r=0.44, p<0.05). 4. Demineralized hydroxyapatite crystals showed central and peripheral dissolving and widening of intercrystal spaces under the AFM. 5. In dentin remineralization small crystal precipitation occurred between the large crystals. We conclude that by adjusting acidulated buffer solution's degree of saturation, we can control enamel and dentin remineralization. In addition, the AFM is highly useful in evaluating changes in remineralized and demineralized hydroxyapatite crystals.

• Korean Institute of Interior Design Journal
• /
• v.16 no.3 s.62
• /
• pp.38-45
• /
• 2007

In the architectural space of modem age, expanding to the vertical and horizontal direction for the interaction between space and space is becoming an indispensable factor, and in this expansion, ramps are being positioned as one of the important factors. With an increased use of ramps, they show a variety of changes in types, functions and even concepts. The space where modem ramps are used exhibits a phenomenon that accommodates and expands many functions as well as the confined function of moving people, and is widening the scope of recognition on the functions of ramp. In addition, this phenomenon can be seen as an architectural reflection on the complexation trend of the modem society, the components comprising a ramp contact the body of experiencers closely and thus have a direct effect on their behavior or feeling, and owing to this, it is a space where new functions and meaning are highly likely to be derived. In this study, spaces where ramps are used stay away from an element of uniform vertical movement but have an independent environment within the entire space, thereby being used as a space dominating the nature of the building, not a subsidiary element of it. In this study, therefore, it could be known that spaces in which ramps are used are different in their meaning according to the patterns, not as an element of uniform vertical movement. In addition, these conclusions are the results by analyzing the patterns of ramps taking place in modem spaces and are thought to be helpful in understanding spaces where ramps are used.

• Journal of the Korea Safety Management & Science
• /
• v.12 no.4
• /
• pp.1-11
• /
• 2010

The purpose of this study is, by recognizing that recently, as crimes using information and various adverse-effect phenomena such as hacking and virus occur frequently with rapid development of information network such as Internet in every field of industry, the range of security is widening to the field of industrial areas for preventing the leaking of industrial technology and protecting that technology as well as information security only limited to IT area, and by establishing common concept about industrial security through education on the industrial security at the point of increasing importance of industrial security, to prepare the base of comprehensive risk management system for protecting company's assets (physical factor, technical factor and managerial factor) safely from the random threats or attacks inside and outside the company through assessment of important assets of the company, evaluation of threats and weak points, and risk assessment by building industrial security management system in order to protect company's information assets and resources which are connected to the existence of the company safely from the threats or attacks from inside or outside the company and to spread stable business activities.

• International journal of advanced smart convergence
• /
• v.5 no.4
• /
• pp.15-20
• /
• 2016

When a virtual sound source for 3D auditory system is reproduced by a linear loudspeaker array, listeners can perceive not only the direction of the source, but also its distance. Control over perceived distance has often been implemented via the adjustment of various acoustic parameters, such as loudness, spectrum change, and the direct-to-reverberant energy ratio; however, there is a neglected yet powerful cue to the distance of a nearby virtual sound source that can be manipulated for sources that are positioned away from the listener's median plane. This paper address the problem of generating binaural signals for moving sources in closed or in open environments. The proposed perceptual enhancement algorithm composed of three main parts is developed: propagation, reverberation and the effect of the head, torso and pinna. For propagation the effect of attenuation due to distance and molecular air-absorption is considered. Related to the interaction of sounds with the environment, especially in closed environments is reverberation. The effects of the head, torso and pinna on signals that arrive at the listener are also objectives of the consideration. The set of HRTF that have been used to simulate the virtual sound source environment for 3D auditory system. Special attention has been given to the modelling and interpolation of HRTFs for the generation of new transfer functions and definition of trajectories, definition of closed environment, etc. also be considered for their inclusion in the program to achieve realistic binaural renderings. The evaluation is implemented in MATLAB.

• Journal of the Korean Institute of Rural Architecture
• /
• v.13 no.3
• /
• pp.83-90
• /
• 2011

The purpose of this study is to analyze size and proportion of plan and section, and derive characteristics by types of worship-space in central hall of buddhist temple. This study covers 45 buddhist temples as designated national treasure and treasure. Types of central hall of buddhist temple are 'Columnless Type', 'Inner Column Type', and 'Colonnade Type'. The results are as follows. Firstly, in the proportion of width and length, 'Columnless Type' is mostly represented with 1:0.73, 'Inner Column Type' with 1:0.54 and seems to be widening for the other types, and 'Colonnade Type' is same proportion with 'Columnless Type'. Secondly, in the proportion of width and height, 'Columnless Type' is 1:0.61 and sizes of worship-space of this type are different but the proportion is same. In the 'Inner Column Type', worship-space is enlarged because a buddhist altar is hustled into the rear. Thirdly, in the proportion of length and height, all types are represented with similar proportion as 1:1. Finally, proportion of the volume of worship-space in 'Columnless Type' is 1(width):0.74(length):0.60(height). The case of 'Inner Column Type' is 1:0.57:0.57 and length of worship-space is shortened, so characteristics of horizontality is emphasized. The space of same size with the proportion of 'Columnless Type' is situated in the inside of worship-space in 'Colonnade Type'.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1977.06a
• /
• pp.4.1-4
• /
• 1977

A variety of diagnostic means for evaluating the hearing ability of neonates and infants have been studied so far, and some physical responses of neonates and infants to loud sound is still of much value. The author studied some normal responses of 100 neonates (male 54, female 46) in our neonatal room from Jan, 1977 to April, 1977. We took 90dB pure tone at 3, 000Hz by Beltone Audiometer model l0D (ANSI 1969) for a stimulus. The results are as follows: 1. The range of the examinees' age is between 2 and 3.5 hours (average 2.4 hours), and auropalpebral response is in 39% (eyelid blinking 10%, eyelid widening 29%), Moro reflex in 35%, sucking response in 14%, cessation of movement in 6%, head turning response in 2%, and no response in 4%. 2. The duration of response is between 2 and 5 Seconds (average 3.3 seconds).

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.1
• /
• pp.88-94
• /
• 1991

Maxillofacial deformities are not considered to be a trouble in social life but function. So many maxillofacial plastc surgeons has made efforts to overcome these troubles and bring out more positive life. The proper proportion and shape decide esthetic quality. Lower third of face was consist with lip, cheek, mandibular lower border and mandibular angle. Widening lower third of face give a impression with muscular and recklessness. And lower and wide mandibular angle makes face square shape. Unilateral involvement cause asymmestric face. These face is considered unfavorable, especially in Korea or Japan. We prevent a number of with mandibular angle Bulging which was corrected with mandibular osteotomy or masseter myotomy.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.26 no.2
• /
• pp.19-32
• /
• 1996

The purpose of this study was to know the proper diagnosis and to establish the treatment plan of the osteosarcoma in the jaws through the clinical, radiological, and histopathologic considerations. The authors compared and analyzed the clinicoradiologic features of the six cases of osteosarcoma, diagnosed at the Dental college hospital in Yonsei University, Seoul, Korea, during the period from 1975 to 1995. The obtained results were as follows; 1. Osteosarcoma occurred in the mean age, 26.2 years, ranged from 14 to 35 years, and equally in men and women. 2. The swelling was the most common frequent presenting complaints. Other reported symtoms included pain, parasthesia of the lower lip or the lesion. 3. The average interval was seen 3.5 months before the patient had been seen by a doctor. 4. The frequency of the lesions was equally in the maxilla, 3 cases and mandible, 3 cases. 5. Radiologically, osteolytic lesions were 2 cases, mixed lesion 1 case, and sclerotic lesion were 3 cases. Periosteal reaction features were shown in 4 cases. A widening of the periodotnal lignament space, one of the earliest signs were shown in 2 cases. 6. Histopathologically, osteoblastic osteosarcoma which is seen in the 3 cases was the most frequent histologic type. Chondroblastic osteosarcoma were seen in the 2 cases. There was no correlation between the radiologic appearance and hitopathologic type.

• Journal of Digital Contents Society
• /
• v.19 no.2
• /
• pp.285-292
• /
• 2018

Though the latest ICT technology is expected to serve as a bridgehead for future industrial development as the core of the 4th Industrial Revolution, the gap in ICT technology is still directly connected to the disparity in wealth and it is widening. Training to foster female ICT capabilities in developing countries is an opportunity to foster quality workforce for national development and a means to close the technology gap. The study aims to investigate the status of infrastructure and ICT education at UHP University in Indonesia, as a preparation for educating students in developing countries with ICT skills. Based on this survey, we develop appropriate ICT education contents for female students and provide necessary policies for ongoing education. We will seek ways to improve efficiency in education by comparing and analyzing the results of the previous research, Life University survey.

• The Journal of Korean Association of Computer Education
• /
• v.12 no.6
• /
• pp.41-51
• /
• 2009

The purpose of this study was to suggest policy implications for bridging digital divide of the students of multicultural background. Specifically, through maximizing equity of Information technology, the current study suggested the need for greater intervention and comprehensive strategies in the interests of a socially inclusive information society, of benefit to the IT disadvantaged. To achieve the research goal, I reviewed a variety of policy reports and previous studies related to the issue of digital divide and multicultural education, and draw useful implications for the policy change. The major research results were as the following: a policy change in a support of personal computer toward public place rather than individual home, widening use of e-learning service as a tool for bridging the digital divide, and the training for teachers and parents to provide an effective education to reduce the digital divide.