A Hybrid Rule-Neural Approach for Transfer-based Machine Translation in Low Korean-Sign-Language Resource Environments

Doctor기계 번역은 서로 다른 언어를 사용하는 사람 사이의 의사소통과 외국어로 표현된 정보에 대한 접근성을 높이는 것을 목적으로 사용된다. 청각 장애인들이 사용하는 언어는 그 지역의 구화 언어와 다르기 때문에 일상 생활에서 비장애인과의 의사소통 및 언어로 표현된 정보를 접하는데 큰 어려움을 가지고 있다. 수화를 다루는데 있어서 필요한 여러 자원이 적기 때문에 수화를 다루는 시스템을 작성하는데 어려움이 있다. 본 학위논문에서는 저자원 환경에서 한국어-한국 수화 시스템을 구축하기 위한 방법을 제시한다. 이 번역 시스템에서는 먼저 한국어-한국수화 번역 사전을 구축하여 이에 기반한 단어 번역을 진행하고 데이터-규칙 복합 방식으로 문장구조를 변환하여 한국수화 번역문을 생성한다. 단어분석 단계에서는 한국어 입력문장의 단어를 의미 수준에서 분석하고 이 의미에 따라 적합한 수화를 사저에서 선책하도록 한다. 문장구조 변환에 있어서, 한국수화의 어순이 부분순서 결정으로 설명될 수 있음에 착안하여 문장에서 어순 결정이 필요한 부분을 "order-important constituent pair"로 분리하고 이를 데이터 기반분류 문제로 풀어내는 방식을 제안한다. 분류기를 사용한 어순 결정에 있어서 한국수화 데이터 부족의 문제를 해소하기 위해 대량의 외부 데이터를 사용하는 신경망 기반 분류 모델을 제안한다. 이 제안 방식은 TV 뉴스 데이터를 사용한 평가 실험 에서 기본 시스템의 성능을 크게 웃돌아 BLEU 점수로 0.514, RIBES 점수로 0.426를 달성하였다.Machine translation has the purpose to break the language barrier that prevents communication with others and to increase accessibility to information. The deaf people face huge language barriers in their daily lives including access to written and spoken information. There are very few machine-readable linguistic resources to process sign language expression. In this thesis, we present a transfer-based machine translation system for translating Korean-to-Korean Sign Language (KSL) with gloss notation, mainly comprised of 1) dictionary-based lexical transfer and 2) a hybrid structural transfer based on a data-driven approach. In particular, we formulate complicated partial word reordering problems in the structural transfer as multi-class classification tasks and propose “syntactically guided” data-driven structural transfer. The core part of our study is a neural classification model, which use external large data, for reordering "order-important constituent pairs" with a reordering task that is newly designed for Korean-to-KSL translation. The experimental results evaluated on news transcript data show that the proposed system achieves a BLEU score of 0.514 and a RIBES score of 0.426, significantly improving upon the baseline system performance

A STUDY OF THE MICROLEAKAGE AT THE POST AND CORE AND TOOTH INTERFACE

Post and core is used to restore endodontically treated teeth, and it is a very important part which supplies retention and support to the prosthesis. But occasionally, caries occured due to the microleakage at the post and core and tooth interface, the failure of prosthesis has happened. In this study, the microleakage of cast gold post and core, amalgam core, and composite resin core was investigated and compared. The coronal part of the extracted upper anterior teeth were removed and endodontically treated with conventional method. The teeth were divided into three groups. In group 1, cast gold post and core was cemented with resin cement and in group 2, ready-made post was cemented with resin cement and amalgam core was built. In group 3, ready-made post was cemented with resin cement and composite resin core was built. All specimens were thermocycled between with dwell time of 15 seconds, and immersed in 0.5% aqueous solution of basic fuchsin dye for 24 hours. After embedded in the epoxy resin, the specimens were sectioned longitudinally and observed with stereomicroscope with the magnification of 25. From the findings of this study, the following conclusions were obtained. 1. There was microleakage at the core/tooth interface of all specimens. 2. The microleakage of gold post and core was significantly less than those of the other two groups. 3. There was no significant difference between the microleakage of amalgam core and that of composite resin core

THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF STRESS DISTRIBUTION IN PORCELAIN LAMINATE VENEERS WITH VARIOUS AMOUNTS OF INCISAL COVERAGE AND TYPES OF INCISAL FINISH LINE UNDER TWO LOADING CONDITIONS

The success of porcelain laminate veneer depends on the bond strength between tooth structure and ceramic restoration and the design of tooth preparation. In particular, incisal coverage and incisal finish line are the two most important factors in long-term fracture resistance. Although the majority of clinicians are practicing incisal coverage and there are various opinions on the geo-metrical ratio between the clinical crown length of the remaining tooth structure and the length of incisal extension in porcelain laminate veneer and the optimal incisal finish lines. scientific evidence still loaves much to be desired. The purpose of this study was to determine the effects of the amounts of incisal coverage and the types of incisal finish line on the stress distribution in maxillary anterior porcelain laminate veneers under two different loading conditions. Three-dimensional finite element models of a maxillary anterior porcelain veneer with differ-ent amounts of incisal coverage ; 0, 1, 2, and 3mm and different incisal finish lines feathered edge, incisal bevel, reverse bevel and lingual chamfer with various amounts of lingual extension were developed. 300N force was applied at the point 0.5mm cervical of the linguoincisal edge in two loading conditions ; A) 125 degrees, B) 132 degrees. Tensile and compressive stress in ceramic and shear stress in the resin cement layer were analyzed using three-dimensional finite element method. The results were as follows : 1. The types of incisal finish line had more influence on the stress distribution in porcelain laminate veneer than the amounts of incisal coverage. 2. In case of no incisal coverage, incisal beveled laminate exhibited more evenly distributed tensile stress than feathered edged laminate. And in case of incisal coverage, reverse beveled laminate and lingual chamfered laminate with 1mm lingual extension exhibited more evenly distributed tensile stress than lingual chamfered laminates with 2mm and 3mm lingual extension. 3. As long as the lingual chamfer goes, less tensile stress was found at the incisal edge, while much more tensile stress was found at the lingual margin area in proportion to the length of lingual extension. 4. Under 125 degree load, tensile stress in porcelain laminate veneer had increased compared with that under 132 degree load and the difference exhibited by the change of the amount of tooth support was larger. 5. The types of incisal finish line and the distance from the incisal finish line to the loading point had more influence on the shear stress distribution in the resin cement layer than the amounts of incisal coverage. In contrast loading condition had little influence

A STUDY ON DIMENSIONAL STABILITY OF IMPRESSION MATERIALS FOLLOWING IMMERSION DISINFECTION

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable

THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF STRESS DISTRIBUTION IN ALL-CERAMIC CROWNS WITH VARIOUS FINISH LINE DESIGNS AND INCISAL REDUCTIONS UNDER DIFFERENT LOADING CONDITIONS

The purpose of this study was to determine the effect of finish line design, amount of incisal reduction, and loading condition on the stress distribution in anterior all-ceramic crowns. Three-dimensional finite element models of an incisor all-ceramic crown with 3 different finish line designs : 1) shoulder with sharp line angle 2) shoulder with rounded line angle 3) chamfer : and 2 different incisal reductions : 2mm and 4mm were developed. 300 N force with the direction of 45 degree to the long axis of the tooth was applied at 3 different positions : A) incisal 1/3, B) incisal edge, C) cervical 1/5. Stresses developed in ceramic and cement were analyzed using three-dimensional finite element method. The results were as follows : 1. Stresses were concentrated in the margin region, which were primarily compressive in the labial and tensile in the lingual. 2. Stresses were larger in the area near line angle than on the crown surface of the margin region. In case of shoulder with sharp line angle, stresses were highly concentrated in the porcelain near line angle. 3. At the interface between porcelain and cement and at the porcelain above the margin on crown surface, stresses were the highest in chamfer, and decreased in shoulder with sharp line angle and shoulder with rounded line angle, respectively. 4. At the interface between cement and abutment on crown surface, stresses were the highest in shoulder with sharp line angle, and decreased in shoulder with rounded line angle and chamfer, respectively. 5. The amount of incisal reduction had little influence on the stress distribution in all-ceramic crowns. 6. When load was applied at the incisal edge, higher stresses were developed in the margin region and the incisal edge than under the other loading conditions. 7. When load was applied at the cervical 1/5, stresses were very low as a whole

The effect of surface treatment on fracture strength of dental ceramics

The major influencing factors on the strength of all-ceramic crowns are types of dental ceramics, fabrication techniques, methods of abutment preparation and cementation modes of all-ceramic restorations. Zinc phosphate cement and glass-ionomer cement were used as an early lot-ing media for all-ceramic crowns. Recently many studies have reported that resin cements have more advantages in increasing the fracture strength of restorations comparing with zincphosphate cement and glass-ionomer cement. The purpose of this study is to investigate the effect of etching, silane treatment, sandblasting and dentin bonding agents on fracture strengths of dental ceramics. 40 flat dentin specimens and 40 ceramic discs of 1.5mm thickness and 8mm diameter were fabricated, and divided into 4 groups according to surface treatments. Surface treatments before cementation were as follows Group I : (ceramic) : HF etching - silane treatment - application of bonding resin (dentin) : application of dentin bonding agent Group II : (ceramic) : sandblasting - application of bonding resin (dentin) : application of dentin bonding agent Group III : (ceramic) : application of bonding resin (dentin) : application of dentin bonding agent Group IV : (ceramic) : HF etching - silane treatment - application of bonding resin (dentin) : no dentin bonding procedure Dentin specimens and ceramic discs were cemented with dual cure resin cement, and went through thermocycling. Compressive stress es were loaded on the centers of ceramic discs with Instron test-ing machine, and fracture strengths resistance for catastrophic fracture were measured The results were as follows. 1. The group I showed the highest fracture resistance. The next was group II And group III, IV followed. 2. There was a significant difference in the mean value of fracture strengths between group I and group III (p0.05). 3. There was a significant difference in the mean value of fracture strengths between group I and group IV (p<0.05)

A STUDY ON FRACTURE STRENGTH OF CONVENTIONAL AND COPY-MILLED IN-CERAM CROWNS

The purpose of this study was to compare the fracture resistance of copy-milled and conventional In-Ceram crown. Four groups of ten uniform sized all-ceramic crowns were fabricated. In-Ceram Spinell and In-Ceram Alumina crowns were fabricated as control group, Celay In-Ceram Spinell and Celay In-Ceram Alumina crowns were fabricated as test group. All specimen were cemented on stainless steel master die with resin cement, and stored in water for 1 day prior to loading in Instron testing machine. Using a steel ball at a crosshead surfed of 0.5mm/min, the crowns were loaded at angle until catastrophic failure occurred. The results obtained were as follows : 1. With the value of , the strength of Celay In-Ceram Alumina crowns had a significantly higher fracture strength than conventional In-Ceram Alumina crowns () (P0.05). 3. The In-Ceram Alumina crowns had a significantly higher fracture strength than In-Ceram Spinell crowns in both methods(P<0.05). 4. Ther order of fracture strength was as followed : Celay In-Ceram Alumina, In-Ceram Alumina, Celay In-Ceram Spinell and In-Ceram Spinell crown

STUDY ON THE DISTORTION OF THE COPINGS FOR CERAMOMETAL CROWNS DURING REPEATED FIRING

Ceramometal crowns are common restorations in fixed prosthodontics because of their casting accuracy, the high strength properties of the metal, and the cosmetic appearance of porcelain. However, deterioration of the initial fit of the metal coping has been observed after the porcelain firing cycle. The distortion due to repeated firing makes it difficult to fit crown margin and elicits microleakage. The major causes of distortion are the residual stress that accumulate during wax-up, casting, cold work and the induced stress caused by the mismatch of porcelain-metal thermal contraction. This study examined the marginal fit changes of metal copings in relation to repeated firing and the effects of heat treatment that reduce the distortion resulted from residual stress. The marginal changes of the copings that were treated with conventional method and those treated with heat before repeated firing, were evaluated. The metal die which represented preparations of a maxillary central incisor was fabricated, and 45 wax patterns were cast with nonprecious metal alloys. The heat treatment of each group was performed as follows. Group 1(control) : Casting - Devesting - Cold work - Firing Group 2 : Casting - Heat treatment - Devesting - Cold work - Firing Group 3 : Casting - Devesting - Cold work - Reinvesting - Heat treatment - Devesting - Firing The copings were fired 3 times. After each firing, the marginal fit changes were measured with inverted metallurgical microscope at the 4 reference points located at labial, lingual, and both proximal surface. Measurements were compared, and statistically analyzed. The results were as follows ; 1. In all groups, the highest value of marginal fit changes of the copings studied were found after the first firing cycle. 2. When the distortion of each experimental group at the first firing cycle were compared, group 1 exhibited the greatest changes(), followed by group 2(), and group 3(). 3. The copings treated with heat before devesting(group 2) revealed significantly smaller marginal fit changes than the copings treated with conventional method(group 1). (p0.01