• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1286-1290
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• 2003

This paper presents a newly implemented parallel finite element procedure for contact-impact problems. Three sub-algorithms are includes in the proposed parallel contact-impact procedure, such as a parallel Belytschko-Lin-Tsay (BLT) shell element generation, a parallel explicit time integration scheme, and a parallel contact search algorithm based on the master slave slide-line algorithm. The underlying focus of the algorithms is on its effectiveness and efficiency for inclusion in future finite element systems on parallel computers. Throughout this research, a prototype code, named GT-PARADYN, is developed on the IBM SP2, a distributed-memory computer. Some numerical examples are provided to demonstrate the timing results of the procedure, discussing the accuracy and efficiency of the code.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.153-168
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• 1994

The aim of the present study was to investigate a relation between occlusal wear area and occlusal contact patterns. For the purpose, occlusal wear area were measured in 58 dental students and in 129 patients with temporomandibular disorders(TMDs) from dental casts. Teeth used in this study were from canine to second molar on both sides in upper arch, totally ten. Occlusal wear area on casts was marked by pencil and photocopies, and then, the area was measured with planimeter. Occlusal relation was clinically examined with regard to Angle's classification, chewing side preference, lateral guidance pattern and bruxing and/or clenching habit. T-Scan, electronic occlusal contact analyzer, was used to record occlusal contact number, contact force, contact time and occlusal balance that is TLR(total left-right statistics) during tooth contact. All measurement were repeated 3 times and the average value was used for data processing. The obtained results were as follows : 1. Mean value of occlusal wear area did not differ significantly between dental students and patients. 2. There ws not significant difference in wear area between chewing side and non-chewing side in both groups. 3. Occlusal wear area was significantly increased with age in both groups. 4. Three subgroups divided by Angle's classification did not show any difference in occlusal wear area among them, but three subgroups divided by lateral guidance pattern showed slightly significant difference between canine guide subgroup and group function subgroup in patients. Occlusal wear ares\a in group function subgroup wear larger than canine guide subgroup. 5. Mean value of wear area in patients with bruxing and/or clenching habit did not differ from those in patients without such habit. 6. Correlationship among items related to occlusal contact pattern were highly consistent and significant in dental students and only one item significantly correlated with occlusal wear area was tooth contact time.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.242-245
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• 2003

A garter spring, which is a long, special, close-coiled extension spring with its ends joined to form a ring, is used in tulip contactor between vacuum circuit breaker and bus bar in switchgear. To carry short-time current and resist welding at the contact surface in the tulip contactor, the garter spring must transmits an uniform contact force to the contact surface through the contact chips arranged in the circumference of bus bar. In this paper, the system for measurement of the contact force by the garter spring is developed. Using the developed measurement system, the design of the connection structure including the garter spring is reviewed to obtain the uniform contact forces in all of contact chips.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.279-282
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• 2002

In this paper, we discuss influence of process condition on contact resistance in WSix deposition process. In the WSix deposition process, we confirmed that word line to bit line contact resistance(WBCR) due to temperature of word line WSix deposition among various process condition split experiment. RTP treatment, d-poly ion implantation dose and thickness was estimated a little bit influence on contact resistance. Also, life time of shower head in the process chamber for WSix deposition related to contact resistance. The results obtained in this study are applicable to process control and electrical characteristics for high reliability and high density DRAM's.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.82-88
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• 1999

This study was to evaluate disinfection efficiency of chlorine and chloramine as secondary disinfectants in the distribution systems. Indicator organism, HPC in the suspended and attached were measured for copper, galvanized steel, PVC, and carbon steel pipes. For suspended microorganism, the PVC pipe was markedly dense among the assessed pipe materials. The attached microorganism was markedly equivalent roughness of pipe materials. In copper and galvanized pipes, chloramine was more effective that free chlorine to disinfect suspended microorganism in the contact time of 2 hours. The contact time for the 99% inactivation of suspended microorganism by chloramine was longer than that of free chlorine. Regardless of pipe materials, chloramine was effective on both disinfection efficiency and 99% inactivation time for attached microorganism. In conclusion, chloramine which is good disinfectant for long contact time was recommended as secondary disinfectant in distribution system.

• Journal of Welding and Joining
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• v.16 no.2
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• pp.122-128
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• 1998

This investigation was performed to collect fundamental informations concerning the behavior of glass solders on ceramic joining process. The wettability of glasses on two types of alumina was evaluated by sessile drop method. SiO$_2$-CaO-Al$_2$O$_3$system glasses were selected as solder glasses, and alumina that have different purities were used for substrate materials. It is indicated that contact angles of glasses on 99% purity of alumina substrate do not change as increasing time at elevated temperature, however the contact angles on the 92% purity of alumina substrate exhibit the strong time dependency. The time-dependent property on 92% alumina was due to the interlayer reactions occurred between the glass solder and impurities on the substrate.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.3
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• pp.334-341
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• 1998

This paper proposes an algorithm to obtain the time-to-contact between an observer and a target and surface orientation of the target. These two physical elements are computed from the image deformation of a known shape, which is extracted by supervised classification of detected line segments based on MAP and Mahalanobis distance. The proposed algorithm was applied to the natural outdoor traffic scene and would contribute to the development for a collision avoidance system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.501-505
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• 1996

In CMM system, a contact probe is not applicable to very small, or flexible elements. There is need to develop non-contact probes of CCD camera. But non-contact probes have some technical problems, including distortion, user interface and time delay. This development gives the foundation of the non-contact probe system and some useful solutions for the problems. The results can be useful for industry application.

• Journal of the Korean Society of School Health
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• v.20 no.2
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• pp.59-68
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• 2007

Purpose: The purpose of this study was to investigate the difference of sexual behaviors of college students according to internet pornography contact. Methods: Subjects consisted of 472 students of K college located in chungcheongbuk-do. The data were collected through a self-administered questionnaire from May, 21 to May, 31, 2007. Results: Eighty-seven percent (87.3%) of respondents contacted internet pornography. As for the first time they contacted it, forty-eight percent(48.3%) contacted it when they were middle school students. Forty-three percent(43.6%) contacted it one time per several months and twenty-one percent(21.2%) contacted it within 10 minutes. Sexual behaviors(hand grasping, hugging, kiss, masterbation, coitus, pregnancy, love expression in public place) showed significant differences according to Internet pornography contact experience, period, frequency, and time. Conclusion: College administration should investigate sexual behavior patterns according intemet pornography contact and provide all college students regular sexual health promotion program.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.365-373
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• 2006

This study suggested correction of excessive mouth opening or maximum occlusal contact to analyse occlusal contact time, occlusal contact number and force through evaluation of occlusal pattern in policemen with temporomandibular disorders. The community of policemen influence on temporomandibular disorder's development and progress due to other condition of mouth opening and maximal occlusal contact. Repeated training or changes of usual life style may cause imbalance of stomatognathic system including the masticatory muscle, then develop or aggravate pain of temporomandibular joints and associated structures. This study uses T-scan II system(Tekscan Co., USA) for evaluation on occlusal pattern may influence temporomandibular disorders, and then the subjects take a sensor at 20 mm opening for maximal occlusal contact force. The policemen with temporomandibualr disorders get more long time on maximum contact timing, more short on end contact timing, and more force on end contact force than general society's. So they get closure of mouth with more short time and more force, then transfer remaining load to temporomandibular joint. There are no statistically significances between affected side and occlusal pattern of occlusal contact time and force. There are Left -right dental arch imbalances seems on Rt. dental arch if affected side is right and Lt. dental arch if affected side is left. In above results, It's worth due consideration that policemen with temporomandibular disorders get more smooth mandibualr movement and less force on maximal occlusal contact position.