• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1412-1416
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• 2009

최근의 극심한 기상이변으로 인하여 발생되는 이상호우의 예측에 관한 사항은 치수 이수는 물론 방재의 측면에서도 역시 매우 중요한 관심사로 부각되고 있다. 강우를 예측하기 위해 많은 방법들이 사용되고 있으나 강우의 메커니즘은 매우 복잡하여 수문순환과정에서 가장 예측하기 힘든 요소이며, 추계학적 예측모형이나 확정론적 예측모형 모두에 있어 상당한 불확실성을 내포하고 있다. 기상예측모형 등을 이용하여 강우예측에 대한 정도를 높여가고는 있으나 많은 수문학적 모형에서 요구하는 시공간적으로 정도가 높은 강우를 예측하기에는 힘들다. 인공신경망은 과거자료의 입 출력 패턴에서 정보를 추출하여 지식으로 보유하고, 이를 근거로 새로운 상황에 대한 해답을 제시하도록 하는 인공지능분야의 학습기법으로 인간이 과거의 경험과 훈련으로 지식을 축적하듯이 시스템의 입 출력에 의하여 연결강도를 최적화함으로서 모형의 구조를 스스로 조직화하기 때문에 모형의 구조에 적합한 최적 매개변수를 추정할 수 있다. 따라서 정확한 예측이 어려운 강우사상을 과거의 자료로부터 신경망의 수학적 알고리즘을 통해 강우의 예측에 적용할 수 있을 것이다. 따라서 본 연구에서는 이러한 인공신경망의 기법 중 오류 역전파 알고리즘을 통하여 과거의 강우사상들을 입 출력 자료로 이용하여 인공신경망을 학습시켜 강우의 예측에 대한 정도를 높이도록 하였다.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.11-20
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• 1989

마이크로 일렉트로닉스(Microelectronics)를 중심으로 하는 산업혁명이 진행되고 있는 시점에서 전자, 광학 또는 신소재 부품에 대한 형상과 치수 또는 표면거칠기에 대한 정확도와 정밀도가 엄격하게 요구되고 있다. 예를 들어 경취 재료인 반도체의 웨이화( w-afer), 수정진동자 자기헷트, 비구면렌즈 또는 연질 금속의 레이저빔(Laser Beam) 프린터 용 포리곤 밀러(Polygon Mirror), 자기디스크, 복사기용 드럼(drum), 레저기기용 반사밀러 등 가공정밀도를 향상시키기 위해서는 과거의 가공기술을 대치할 수 있는 새로운 초정밀가공 기술의 도입이 활발하게 진행되고 있다. 경취성 재료의 초정밀가공은 지금까지는 랩핑(lappi- ng), 폴리싱(polishing)의 가공기술이 주체였으나, 최근의 엄격한 부품정밀도에 대응하기 위하여 전가공을 초정밀 연삭가공으로 평면도,표면거칠기, 가공변질층을 향상시키고 다듬질 가공은 폴리싱으로 하여 표면거칠기를 향상시켜야 하는 가공기술이 보급되고 있다. 일반연질 금속의 다듬질가공은 유리지립을 이용하는 랩핑이나 폴리싱으로 다듬질 가공을 진행하고 있었 으나 형상정도와 표면정밀도를 동시에 얻는다는 것이 어렵고 또 가공시간이 너무 길어서 매우 고가인 것이 되고 말았다. 그러나 유리에서 연질금속으로 재료를 전환시키고 저가격화, 양산 화의 요구, 정밀도 향상과 부품의 안정화 등등 여러 이유로서 다아아몬드(Diamond) 공구로 mirror surface 를 만드는 초정밀 경면연삭 가공기술(precision turning with diamond)의 발달 로 이제는 완전히 새로운 가공기술로 대치되고 말았다. 다이아몬드에 의한 초정밀절삭은 공구 끝이 매우 예리하고 마모가 매우 적은 단결정 다이아몬드를 이용하고 절삭가공 기계는 운동정도 를 피가공물에 정확히 전사 시키는 방법이며 따라서 가공기계는 고도의 운동정밀도가 요구되며 그외에 강성, 진동, 열변이, 제어면에서 엄격한 검도가 있어야 한다.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.92-97
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• 2004

Traumatic injuries in the young peranent dentition are common, but root fractures, defined as fractures in volving dentin, cementum and pulp, are relatively uncommon. Case 1 is a 9-year-old boy who had a horizontal root fracture of his maxillary right central incisor in the apical third. Root canal therapy was performed in coronal segment and calcium hydroxide therapy was initiated. Six months after treatment, a periapical radiograph showed calcific tissue formation and normal root development. 1 year and 3 months later, the canal was permanently obturated with gutta-percha. Case 2 is a 7-year-old girl who had a vertical root fracture of her maxillary right central incisor. Fractured tooth was intentionally extracted atraumatically, and then the separated fragments are bonded with resin cement. the restored tooth was replanted into the original socket. Recalls up to 8 months showed normal mobility and no periapical pathosis. In these cases, we performed conservative treatment. Clinical and radiographic examination showed no pathosis or abnormality of the teeth and periodontal tissue.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.296-303
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• 2013

Lysyl oxidase (LOX), extracellular matrix enzyme, is catalyzing lysine-derived crosslinks in collagen and elastin. Recently, several LOX-like proteins (LOXL, LOXL2, LOXL3 and LOXL4) have been identified in human but their specific functions are still largely unknown. The purpose of this study was to evaluate the function of the LOX family genes during odontoblastic differentiation of human dental pulp (HDP) cells induced with odontogenic supplement (OS). The messenger RNA (mRNA) expression of LOX family genes and differentiation markers was assessed by reverse transcriptase polymerase chain reaction analysis (RT-PCR). The formation of mineralization nodules was evaluated by alrizarin red S staining. Amine oxidase activity of HDP cells was measured by peroxidase-coupled fluormetric assay. The expressions of differentiation markers, such as alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), dentin matrix protein1 (DMP1), dentin sialophosphoprotein (DSPP) in HDP cells were increased after treatment with OS media. The LOX and LOXL mRNA expression were gradually increased in OS media, whereas LOX enzyme activities were markedly detected on day 7. The mRNA expression and LOX enzyme activity of collagen type I was very similar to the pattern of LOX gene. In this study, the expression of LOX and its isoforms, and activity of LOX were highly regulated during odontoblastic differentiation. Thus, these results suggest that LOX plays a key role in odontoblastic differentiation of HDP cells.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.321-329
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• 2013

Although it has been reported that lysyl oxidase (LOX) is involved in odontoblastic differentiation, the role of LOX on odontoblastic differentiation by hydrogen peroxide ($H_2O_2$) have not been clarified. In the present study, we investigated whether $H_2O_2$, reactive oxygen species (ROS), is modulated the messenger RNA (mRNA) expression and activity of LOX during odontoblastic differentiation of human dental pulp (HDP) cells. The mRNA expression was quantified by reverse transcriptase polymerase chain reaction (RT-PCR) analysis, and LOX enzyme activity was measured by high sensitive fluorescent assay. Expression of the odontoblastic differentiation marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX and LOXL. The $H_2O_2$-induced mRNA expression of LOX family was significant reduction of LOX, LOXL, and LOXL3 mRNA levels in HDP cells. LOX enzyme activity was increased at $H_2O_2$ 0.3 mM for 24 hours. The mRNA expression of alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) was inhibited by LOX- and LOXL-specific siRNAs whereas the mRNA expression of dentin matrix protein1 (DMP1), and dentin sialophosphoprotein (DSPP) was inhibited by LOX-specific siRNA. In LOX enzyme activity, siRNA-induced knockdown of both LOX and LOXL inhibited the total amine oxidase activity in HDP cells, as in the case of mRNA expression. In conclusion, the essential role of $H_2O_2$ on odontoblastic differentiation suggests that its regulation by LOX may have pharmacologic importance in HDP cells.

• Journal of Korea Water Resources Association
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• v.39 no.1 s.162
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• pp.1-9
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• 2006

Recently, the flood damages including losses of human lifes and property have been rapidly increased according to extreme floods. And we know that the flood control project is needed for diminishing flood damages. However, we have had the lacks in a reasonable methodology for the economic analysis of food control project. This study aims to improve the existing economic analysis method for flood control project. So, first of all, we understand the problems of existing economic analysis and investigate the methodologies of foreign countries. Based on that, the Multi-Dimensional Flood Damage Analysis(MD-FDA) is developed in this study. The survey of properties on the floodplain is conducted, then the damage rate obtained by evaluating the monetary values of surveyed property is applied, and the expected flood damage is calculated. Also by considering damage area in the floodplain as well as spatial distribution of inundated depth using GIS, the flood damages are evaluated more accurately than existing method. From the study, we know that the MD-FDA can improve the problems of existing method and evaluate the reasonable flood damages by using updated nation리 statistics.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.375-381
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• 2005

Er:YAG laser has been considered a promising alternative to dental drill and many researches indicate that adjustment to variable parameters, including water flow rate, pulse energy and pulse repetition rate, can be made to improve ablation ability and efficiency of the laser. Of these parameters, addition of water spray during irradiation has been thought to ablate dental hard tissue more rapidly and safely. The purpose of this study was to investigate tooth ablation amount by Er:YAG laser irradiation as related to varied water flow rates added and, ultimately to find the most effective water flow rate for ablation. In addition, the temperature change of pulp chamber during irradiation was also monitored on the irradiated and opposite pulpal walls, respectively. An Er:YAG laser with contact mode was employed. Extracted human molars were split into two pieces for ablation experiment. Pulse energies of 200 and 300 mJ with a pulse repetition rate of 20 Hz and 5 water flow rates (1.6, 3.0, 5.0, 7.0, and 10.0 ml/min) were applied. Each irradiation was performed for 3 seconds. According to these parameters, experimental groups were divided into 10 subgroups which consisted of 5 specimens. For temperature experiment, another 5 tooth-specimens were prepared in the manner that pulp chamber was open through access cavity preparation and two temperature-measuring probes were placed respectively on the irradiated and the opposite walls of pulp chamber. From the experiment on ablation amount related to different water flow rates, it was shown that the least water flow rate of 1.6 ml/min ablated more than any other water flow rates (p<0.000). When the irradiation for 3 seconds, combined with the pulse repetition time of 20Hz and the water flow rate of 1.6 ml/min was done to tooth specimen, the temperature rise was not noticeable both on the irradiated and the opposite pulpal walls (less than 3$^{\circ}C$) and there was no significant difference in temperature rise between the two pulse energies, 200 and 300 mJ. From the results of this study, it is suggested that tooth ablation with Er:YAG laser can be done effectively and safely at a energy between 200 and 300 mJ/pulse and a pulse repetition rate of 20 Hz when the lasing is conjugated with the water flow rate of 1.6ml/min.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.365-376
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• 1999

The importance of finishing and polishing the restoration has been described by several authors. The final step provides for improved metallurgical properties, better marginal adaptation, reduced plaque accumulation. Unfortunately, finishing of the restorations can produce damage from temperature rises at the pulpal wall. The aim of this study was to determine the changes in temperature can be occurred during the use of finishing and polishing instruments under a variety of conditions. ; with or without a water coolant, intermittent or continuous operation, high or low rotation speed, remaining dentin thickness and various restorative materials. Class V preparations were cut on extracted molars and restored with composite resin(Z 100), resin-modified glass ionomer cements(Dyract, Fuji II LC), and amalgam. Finishing was done with aluminum oxide coated disc($Sof-lex^{(R)}$ polishing disc, 3M, USA). The following results were obtained. 1. The rise of temperature during polishing of amalgam restorations was the highest among the all experimental groups except polishing with water coolant(P<0.05). However, there were no statistical differences in temperature rises between Z 100, Dyract and Fuji II LC(P>0.05). 2. The intrapulpal temperature was greatly influenced by the applied time, and intermittent polishing was showed significantly lower temperature rises than continuous polishing(P<0.01). 3. The intrapulpal temperature was increased according to the application of polishing regard less of using water coolant. However, polishing with water coolant showed significantly lower temperature in the pulp than not used water coolant(P<0.01).

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.6
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• pp.999-1011
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• 2008

To most of the students studying fashion related major, the graduation fashion show is a big challenge. They have to put together all they learn and show what they can do to their future employers. They design, pattern work, and make up garments for the show all by themselves. Unfortunately. while they make up their garments, they usually don't Dow exactly body measurements of the models. So quite often they have to alter their art works up to the last minute of the fashion show opening. Sometimes such unadequate work process ruins their work. The purpose of this study is to suggest block patterns of Korean fashion models measurements for basic items, such as jacket and pants for male models and torso length block pattern, skirt and pants for female models. 20 male and 20 female professional models were measured. The block patterns were based on their measurements. After the first fitting test, patterns were corrected by their body characteristic. For both male and female models, it was found desirable to fix the shoulder width and make an adjustment to the patterns with a deviation of width and girth items. In case of the resultant patterns the satisfaction was made better. Model sizes proposed in this study are considered closer to the size of average models, since they were based on A-grade models who are currently working in Korea. The resultant patterns can be produced by simply making a slight adjustment to the width of the proposed pattern in this study.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.271-279
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• 2002

This study develops the module to find the lateral stiffness influence matrix of each story and performs the displacement sensitivity analysis by virtual load method for the efficiency of optimal design using lateral stiffness influence matrix. Also, resizing technique based on the estimated lateral stiffness increment factors is developed to apply directly the results of optimal design. To this end, resizing technique is divided into the continuous and discrete section design methods. And then the relationships between section properties and section size are established. Specifically, an initial design under strength constraints is first performed, and then the lateral load resistant system is designed to control lateral displacements yet exceeding the drift criteria. Two types of 45-story three dimensional structures we presented to illustrate the features of the lateral drift control and resizing technique for tall buildings proposed in this study.