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This paper presents the operational performance and transient response of a high temperature gas-cooled reactor (HTGR) with an emphasis on the gas turbine through a two-dimensional approach. For its operational and transient simulation we use a GAMMA-T in which the system code, GAMMA, is coupled with the two-dimensional turbomachinery model. We also implement several models into the GAMMA-T: the reactor kinetics model, the bypass valve model, and the models of the core, the heat exchangers, the gas turbine, and the piping. The estimations of compressor and turbine performances are based on a two-dimensional axisymmetric throughflow method that is capable of predicting both the transient and steady-state behavior of the power conversion system (PCS). To demonstrate the code capability, we investigated the two representative transients of GTHTR300, which is a 600 MW direct cycle helium cooled reactor consisting of a prismatic block type core, a horizontal single-shaft configuration of turbomachinery, a recuperator, and a precooler: a loss of heat rejection transient corresponding to the failure of the precooler water supply, and a 30% load reduction transient from nominal operation with bypass control. The simulation results demonstrated the controllability and operational stability for the plant.

In this work, hypersonic aero-thermo post-buckling and thermal flutter behaviors of Functionally Graded (FG) panels under thermal and aerodynamic loads are investigated. The volume fractions of constitutive materials of the panels are gradually varied from ceramic to metal in the thickness direction based on a simple power law distribution. Thus, the material properties of the panel are also changed by a linear rule of mixture. Furthermore, the material properties are assumed to be temperature dependent because the panels are mainly used in the high temperature environments. Using the principle of virtual work, the equations of motion of the first-order shear deformation plate theory (FSDPT) are derived and the finite element method is applied to get the solution. In the formulation, the von Karman strain-displacement relationship is used for structural nonlinearity, and the partial second-order piston theory is adopted to consider the aerodynamic nonlinearity. Newton-Raphson iterative technique is used to solve the governing equations, and linear eigenvalue analysis is performed to obtain the hypersonic flutter boundaries.

We present three nuclear/hydrogen-related R&D activities being performed at KAIST: air-ingressed LOCA analysis code development, gas turbine analysis tool development, and hydrogen-production system analysis model development. The ICE numerical technique widely used for the safety analysis of water-reactors is successfully implemented into GAMMA, with which we solve the basic equations for continuity, momentum conservation, energy conservation of the gas mixture, and mass conservation of 6 species (He, N2, O2, CO, CO2, and H2O). GAMMA has been extensively validated using data from 14 test facilities. We developed a tool to predict the characteristics of HTGR helium turbines based on the throughflow calculation with a Newton- Raphson method that overcomes the weakness of the conventional method based on the successive iteration scheme. It is found that the current method reaches stable and quick convergence even under the off-normal condition with the same degree of accuracy. The dynamic equations for the distillation column of HI process are described with 4 material components involved in the HI process: H2O, HI, I2, H2. For the HI process we improved the Neumann model based on the NRTL (Non-Random Two-Liquid) model. The improved Neumann model predicted a total pressure with 8.6% maximum relative deviation from the data and 2.5% mean relative deviation, and liquid-liquid-separation with 9.52% maximum relative deviation from the data.

The flexible pavement system consists of layered structures. Each layer is composed of different materials and represents different response to loading. Successful pavement design, therefore, requires proper evaluation of mechanical properties for the sublayers, which can realistically describe the behavior of pavement substructures. The resilient modulus is an important mechanical property widely used for the analysis and design of flexible pavements. In this study, a normalized resilient modulus model applicable to both subbase and subgrade materials is proposed. A series of laboratory test results for subbase and subgrade materials are collected and analyzed to investigate effects of the confining and deviatoric stresses on the resilient modulus. Based on test results, a normalized degradation relationship of the resilient modulus as a function of normalized stresses is developed. Values of model parameters for the proposed model are also evaluated and presented. To check validity of the model, a finite element analysis is performed and compared with measured responses of pavement structures.

The volume fraction optimization of functionally graded (FG) composite panels is studied by considering stress reduction and thermo-mechanical buckling. The structure is made up of ceramic layer, functionally graded materials (FGMs) and metal layer. Material properties are assumed as temperature dependent, and continuously varying in the thickness direction according to a simple power-law distribution in terms of the ceramic and metal volume fractions in FGMs. The 3-D finite element model is adopted for modeling of material properties and temperature fields in the structure. For the various FGM thickness ratios and volume fraction distributions, mechanical stress analysis and thermo-mechanical buckling analysis are performed. Based on the results, the optimal designs of FGMs panels are investigated for stress reduction and improving thermo-mechanical buckling behavior.

For designing concrete structures, engineers are provided data from unidirectional flexure test in most cases. But real structural components such as pavements and deck panel are subjected to multiaxial stress throughout their body. Therefore, biaxial flexure test for concrete may be considered as a gage of the performance of concrete in service. In this paper, we propose the optimum biaixial flexture test (BFT) to measure the biaxial flexural strength of concrete. This method are an improved version of the ring-on-ring test which have been used extensively in the fields of ceramics and biomaterials. The optimum geometry of the test specimen was determined by using a three-dimensional finite element analysis. A series of test data obtained from the pro- posed test method is provided to show that the proposed optimum biaxial flexure test method can be used to identify the biaxial tensile strength of concrete.

In this study, thermal post-buckling behaviors and linear flutter analysis of Functionally Graded(FG) panels with structural damping under a supersonic airflow are investigated. First-order shear deformation theory (FSDT) is applied to model the panel, and the von-Karman strain-displacement relations are adopted to consider the geometric nonlinearity. In addition, the damping is modeled as the Rayleigh damping, and the first-order piston theory is applied for the supersonic aerodynamic load.

This paper proposes a domain corpus independent vocabulary generation algorithm in order to improve the coverage of vocabulary for embedded continuous speech recognition (CSR). A vocabulary in CSR is normally derived from a word frequency list. Therefore, the vocabulary coverage is dependent on a domain corpus. We present an improved way of vocabulary generation using part-of-speech (POS) tagged corpus and knowledge base. We investigate 152 POS tags defined in a POS tagged corpus and word-POS tag pairs. We analyze all words paired with 101 among 152 POS tags and decide on a set of words which have to be included in vocabularies of any size. The other 51 POS tags are mainly categorized with noun-related, named entity (NE)-related and verb-related POSs. We introduce a domain corpus independent word inclusion method for noun-, verb-, and NE-related POS tags using knowledge base. For noun-related POS tags, we generate synonym groups and analyze their relative importance using Google search. Then, we categorize verbs by lemma and analyze relative importance of each lemma from a pre-analyzed statistic for verbs. We determine the inclusion order of NEs through Google search. The proposed method shows at least 28.6% relative improvement of coverage for a SMS text corpus when the sizes of vocabulary are 5 K, 10 K, 15 K and 20 K. In particular, the coverage of 15 K size vocabulary generated by the proposed method reaches up to 97.8% with the relative improvement of 44.2%.

This paper proposes an efficient feature vector classification for Speech Emotion Recognition (SER) in service robots. Since service robots interact with diverse users who are in various emotional states, two important issues should be addressed: acoustically similar characteristics between emotions and variable speaker characteristics due to different user speaking styles. Each of these issues may cause a substantial amount of overlap between emotion models in feature vector space, thus decreasing SER accuracy. In order to reduce the effects caused by such overlaps, this paper proposes an efficient feature vector classification for SER. The conventional feature vector classification applied to speaker identification categorizes feature vectors as overlapped and non-overlapped. Because this method discards all of the overlapped vectors in model reconstruction, it has limitations in constructing robust models when the number of overlapped vectors is significantly increased such as in emotion recognition. The method proposed herein classifies overlapped vectors in a more sophisticated manner, selecting discriminative vectors among overlapped vectors, and adds those vectors in model reconstruction. On SER experiments using an emotional speech corpus, the proposed classification approach exhibited superior performance to conventional methods, and displayed an almost human-level performance. In particular, we achieved commercially applicable performance for two-class (negative vs. non-negative) emotion recognition.

Volume fraction optimization of Functionally Graded Materials (FGMs) is investigated considering stress and critical temperature. Material properties are assumed to be temperature dependent, and are assumed to be varied continuously in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituent materials. The effective material properties are obtained by applying linear rule of mixtures. The 3-D finite element model is adopted using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. For the various FGMs volume fraction distributions, mechanical stress analysis and thermo-mechanical buckling analysis are performed to get the critical conditions. Finally, the optimal designs of FGMs panels are investigated for stress reduction and improving thermo-mechanical buckling behavior.

The influences of heat treatment and addition of a small amount of base metal (In, Sn, and Ir) for oxidation in Au–Pt-based alloy were investigated by electron spectroscopy and scanning electron microscopy. Au–Pt-based alloys were prepared by argon-arc melting furnace and then they are heat treated. Oxidation on alloy was significantly affected by addition of base metal (In and Sn) and heat treatment. The bond strength of the alloys was not dependent on the changing heat treatment. These results indicated that the Sn and In could be effective as oxidation elements for porcelain bonding to gold alloys.

Thermal flutter characteristics of functionally graded (FG) ceramic/metal panels under the thermal and aerodynamic loads are investigated. The volume fractions of the constitutive materials are determined by a simple power-law distribution, and material properties are assumed to be a linear rule of mixture. The panels are considered as rectangular plates based on the first-order shear deformation theory, and the von Karman strain–displacement relations are used to account for the geometric nonlinearity. The first-order piston theory is adopted to represent aerodynamic pressures induced by supersonic airflows. The principle of virtual work is applied to derive equations of motion, and a finite element method is used to obtain numerical solutions. The Newton–Raphson method is adopted to obtain approximate solutions of the nonlinear governing equations. Flutter boundaries are defined by eigenvalue analysis, and the Guyan reduction is used to reduce degree of freedom. Flutter motions of FG panels are investigated using the Newmark method. The effects of volume fraction distributions, boundary conditions, temperature changes and aerodynamic pressures on panel flutter characteristics are analyzed in detail.

The amorphous indium tin oxides (ITOs) and the transparent conducting oxides (TCOs) electrode on the flexible polymer substrate, polyvinylidene difluoride (PVDF), and their application to the suggested combinational device system were studied. The lower range ordered crystalline structure of the ITOs enable the reduction of micro-cracks or defect grains under flexible conditions. With the piezoelectric function of substrate polymer, which is added to the display function with OLED (Organic light emitting diodes), the pattern design with the separated electrodes for two devices for emitting light and vibration was considered. From these results, the concept of a combinational flexible electronic device system with a functional polymer substrate could be suggested.

This study concerns the development of dynamic models for a high-temperature gas-cooled reactor (HTGR) through direct implementation of a gas turbine analysis code with a transient analysis code. We have developed a streamline curvature analysis code based on the Newton–Raphson numerical application (SANA) to analyze the off-design performance of helium gas turbines under conditions of normal operation. The SANA code performs a detailed two-dimensional analysis by means of throughflow calculation with allowances for losses in axial-flow multistage compressors and turbines. To evaluate the performance in the steady-state and load transient of HTGRs, we developed GAMMA-T by implementing SANA in the transient system code, GAMMA, which is a multidimensional, multicomponent analysis tool for HTGRs. The reactor, heat exchangers, and connecting pipes were designed with a one-dimensional thermal–hydraulic model that uses the GAMMA code. We assessed GAMMA-T by comparing its results with the steady-state results of the GTHTR300 of JAEA. We concluded that the results are in good agreement, including the results of the vessel cooling bypass flow and the turbine cooling flow.

On the piezoelectric polymer, PVDF (poly vinylidene fluoride), the transparent conducting oxide (TCO) electrode material thin film was deposited by roll to roll sputtering process mentioned as a mass product-friendly process for display application. The deposition method for ITO Indium Tin Oxides) as our TCO was DC magnetron sputtering optimized for polymer substrate with the low process temperature. As a result, a high transparent and good conductive ITO/PVDF film was prepared. During the process, especially, the gas mixture ratio of Ar and Oxygen was concluded as an important factor for determining the film`s physical properties. There were the optimum ranges for process conditions of mixture gas ratio for ITO/PVDF From these results, the doping mechanism between the oxygen atom and the metal element, Indium or Tin was highly influenced by oxygen partial pressure condition during the deposition process at ambient temperature, which gives the conductivity to oxide electrode, as generally accepted. With our studies, the process windows of TCO for display and other application can be expected.

The advanced active twist rotor (AATR) blade incorporating single crystal macro fiber composite (single crystal MFC) actuators is designed and the aeroelastic analysis is performed. The AATR blade is designed based on an existing passive blade and the NASA/ARMY/MIT active twist rotor (ATR) prototype blade. The AATR blade is designed to satisfy all the requirements and the properties of the AATR blade are compared with those of the ATR prototype blade. The aeroelastic analysis of the designed AATR blade for the hover condition is conducted. In order to predict the vibration reduction capability, the twist actuation frequency response of the AATR blade is investigated by the numerical simulation. As a result, although lower input voltage is used, the AATR blade can achieve higher twist actuation that is sufficient to alleviate the helicopter vibration as compared with the ATR blades using the AFC and the standard MFC.

Analysis and optimal design of the smart skin, i.e., the conformal load-bearing antenna structure for buckling and free vibration are studied. The smart skin is modeled as an asymmetric composite sandwich structure which consists of different materials. In order to act as antennas or radars, a dielectric layer is embedded on the middle surface of the sandwich structure. The formulation of the smart skin model is based on the first-order shear deformation plate theory, and numerical results are obtained by the finite element method using a four-node plate element with five degrees of freedom at each node. The buckling and vibration behaviors of the smart skin are investigated with the variation of the aspect ratio, Honeycomb core thickness, area of dielectric layer and fiber angle of face sheet. Furthermore, to maximize the buckling load and the natural frequency of the smart skin, the optimal design is performed using a simple genetic algorithm.

In this study, thermal post-buckling characteristics of functionally graded (FG) panels in hypersonic airflows are investigated. The volume fraction and the material properties of FGMs are continuously changed from ceramic to metal in the thickness direction agreeably to a simple power law distribution and a linear rule of mixture, respectively. Using the principle of virtual work, the governing equations are derived and the finite element method is applied to obtain the solutions. Based on the first-order shear deformation theory (FSDT), the FG panels are modeled by the von Karman strain-displacement relation for the structural non-linearity. Also, the third-order piston theory is employed to consider the aerodynamic non-linearity.

We fabricated highly aligned porous alumina ceramics with interconnection sizes of >50 μm by the unidirectional freeze casting of ceramic/camphene slurries at 3 °C and subsequent treatment at 35 °C for 24 h, followed by sintering at 1600 °C for 3 h. As the initial alumina content employed in the slurry was increased from 10 to 25 vol.% and the porosity was linearly decreased from 82 to 59%, while the compressive strength was remarkably improved from 11 to 95 MPa.

Static and dynamic stabilities of functionally graded (FG) panels which are subjected to combined thermal and aerodynamic loads are investigated. The volume fractions of constituent materials composing the FG panels are assumed to be given by a simple power law distribution. Material properties of the FG panels are obtained by a linear rule of mixture. Panels are considered as rectangular plates which are based on the first-order shear deformation theory. The von Karman strain–displacement relation is used to account for geometric nonlinearity, which is caused by a large deformation. The first-order piston theory is used to simulate supersonic aerodynamic loads acting on the panels. Equations of motion are derived by the principle of virtual work and numerical solutions are obtained by a finite element method. The Newton–Raphson method is applied to get solutions of the nonlinear governing equations. Flutter boundaries are defined by linear flutter analysis and the Guyan reduction is applied to reduce degree of freedom for eigenvalue analysis. The influence of the material constitution, asymmetric characteristics of FG panels on thermal buckling and flutter characteristics are examined. Static and dynamic stability margins of FG panels are defined for various volume fractions.

Piezoelectric fiber composites were developed to overcome drawbacks of typical monolithic piezoceramic (PZT) actuators. Although piezoelectric fiber composites had many improvements over the monolithic PZT, there are still improvements. Thus, the single crystal piezoelectric fiber composite actuator is proposed. Single crystal piezoelectric materials such as PMN-PT have larger piezoelectric strain constants, higher bandwidth and higher energy density than polycrystalline counterparts. Piezoelectric fiber composites can improve the performance of various structures, and can be subject to wide temperature range where the thermoelastic behavior is important. Therefore, this paper studies the coefficients of thermal expansion (CTE) for single crystal piezoelectric fiber composites. The Macro Fiber Composite (MFC) as the piezoelectric fiber composite is considered. To calculate the effective properties of two orthotropic layers of the MFC, PMN-PT(or PZT)/epoxy and copper/epoxy layers, the rule of mixture is adopted. With the effective properties known for each layers, the two CTE of the MFC actuator are obtained from the classical lamination theory considering thermal effects. The difference of the CTE between the single crystal MFC and the standard MFC is studied.

Dissimilar metal welding (DMW) are used widely in various industrial applications due to the practical importance from the technical and economic aspect. However, DMW have several fabricative and metallurgical drawbacks that can often lead to in-service failures. For example, the most pronounced fabrication faults are hot cracks. Recently, DMW have used the several of heat source to decrease such as faults. Laser welding process has, in recent years, attracted more attention due to its special features: a small heat-affected zone and narrow weld bead due to the low heat input; welding at high speed; welding can be carried out in areas of difficult access; contactless energy transfer; welding in an exact and reproducible manner; possibilities for automation and robotization, and welding performed in various atmospheres. In this paper, the weldability on dissimilar metal welding of austenite stainless steel and carbon steel using Nd:YAG laser with a continuous wave was experimentally investigated.

Laser welding process is widely used in the industrial area due to its less affects to base metal than general welding. Laser welding has characteristics that highly affect ratio, deeply penetration depth and small heat affected zone(HAZ) due to its in a short time melting and then solidification by a high energy absorption rate. The objective of this research work is to investigate the optimum conditions of a cold rolled carbon steel(SCP1) in a laser welding process using a Nd:YAG laser with a continuous wave(CW). The determination of optimum conditions were performed to change the laser power, beam speed, focus length and then carry out an butt welding. From the results of the investigation, it has been shown that the optimal welding condition without defects in the vicinity of the welded area and with a good welding quality is 1325W of the laser power, 1.4m/min of laser welding speed and 0mm of focus position.

Current high-temperature gas-cooled reactors (HTGRs) are based on a closed Brayton cycle with helium gas as the working fluid. Thermodynamic performance of the axial-flow helium gas turbines is of critical concern as it considerably affects the overall cycle efficiency. Helium gas turbines pose some design challenges compared to steam or air turbomachinery because of the physical properties of helium and the uniqueness of the operating conditions at high pressure with low pressure ratio. This report present a review of the helium Brayton cycle experiences in Germany and in Japan. The design and availability of helium gas turbines for HTGR are also presented in this study. We have developed a new throughflow calculation code to calculate the design-point performance of helium gas turbines. Use of the method has been illustrated by applying it to the GTHTR300 reference.

Hydroxyapatite has high affinity rate with organic substance in an oral cavity, therefore lately nano-sized hydroxyapatite is extensively researched to increase affinity to tooth and remineralization. The objective of this research is indirectly to investigate the effect of nanohydroxyapatite on remineralization using valuation about whiteness and bacterial contamination of the bovine tooth. We have designed in vitro test for this purpose. The bovine teeth are sliced into human teeth size then the baseline whiteness of total 60 teeth is measured and assigned into 3 groups by cross-matching according to the whiteness. These samples were embedded into resin mold and underwent mechanical brushing during fixed schedule. The whiteness and bacterial contamination of teeth are measured and compared among 3 groups. Each dentifrice used in the experiment is composed of B.S.I group (30% Calcium Carbonate, precipitated-CaCo3) with abrasion rate of 100, Test Ⅰgroup (15% Sodium Metaphosphate, insoluble-NaPo3), Test Ⅱ group (15% Nano-hydroxyapate-Ca10(PO4)6(OH)2. After 20,000 strokes of mechanical brushing with each group sample teeth whiteness is measured for 2nd time and then the sample teeth were submerged into the same solution with oral bacteria for 10 days. The teeth whiteness is measured again for 3rd time and the bacteria from the surface of teeth are cultivated on agar badge for 3 days. We have compared with average of whiteness before and after test in group and each other 3 group. The whiteness of teeth was maintained in test group II, however in other group the whiteness achieved through brushing was lost. Also, Group II had the smallest area of bacterial colony on agar badge (p

The antibacterial brushite-forming calcium phospahte cements (CPC) were prepared using an equimolar mixture of β-tricalcium phosphate (β-TCP) and monocalcium phosphate monohydrate (MCPM) with chlorine dioxide (ClO2) generating powders (sodium chlorite and mixed acid activator). The effect of ClO2 on cement setting time, compressive strength, and antibacterial property of novel antibacterial CPC was investigated. The use of 0.3M citric acid solutions as liquid phase enabled final setting times of 5~10 min. The setting time of antibacterial cement systems was prolonged with increasing the amount of antibiotic used. Dry compressive strength was found to be in the range between 9~15 MPa and increased with addition of ClO2 generating powders. Wet compressive strength was slightly decreased compared to dry compressive strength after immersion of cement samples in water for 24 h. The antimicrobial potency of the different cement formulations was investigated using the agar diffusion method. The acidic brushite cement itself showed the inhibitory effect for Streptococcus mutans. The inhibition zone was increased with the amount of ClO2 generating powders. These results indicate that our novel antibacterial CPC have the great potential to avoid the development of infections for preventive antibiotic therapy.

Scanners are frequently used in the fabrication of dental prostheses. However, the accuracy of these scanners is variable, and little information is available.The purpose of this in vitro study was to compare the accuracy of cast scanners with that of intraoral scanners by using different image impression techniques.A poly(methyl methacrylate) master model was fabricated to replicate a maxillary first molar single-abutment tooth model. The master model was scanned with an accurate engineering scanner to obtain a true value (n=1) and with 2 intraoral scanners (CEREC Bluecam and CEREC Omnicam; n=6 each). The cast scanner scanned the master model and duplicated the dental stone cast from the master model (n=6). The trueness and precision of the data were measured using a 3-dimensional analysis program. The Kruskal-Wallis test was used to compare the different sets of scanning data, followed by a post hoc Mann-Whitney U test with a significance level modified by Bonferroni correction (α/6=.0083). The type 1 error level (α) was set at .05.The trueness value (root mean square: mean ±standard deviation) was 17.5 ±1.8 μm for the Bluecam, 13.8 ±1.4 μm for the Omnicam, 17.4 ±1.7 μm for cast scanner 1, and 12.3 ±0.1 μm for cast scanner 2. The differences between the Bluecam and the cast scanner 1 and between the Omnicam and the cast scanner 2 were not statistically significant (P.0083), but a statistically significant difference was found between all the other pairs (P.0083). The precision of the scanners was 12.7 ±2.6 μm for the Bluecam, 12.5 ±3.7 μm for the Omnicam, 9.2 ±1.2 μm for cast scanner 1, and 6.9 ±2.6 μm for cast scanner 2. The differences between Bluecam and Omnicam and between Omnicam and cast scanner 1 were not statistically significant (P.0083), but there was a statistically significant difference between all the other pairs (P.0083).An Omnicam in video image impression had better trueness than a cast scanner but with a similar level of precision.

PURPOSE. We assessed the repeatability and reproducibility of abutment teeth dental impressions, digitized with a blue light scanner, by comparing the discrepancies in repeatability and reproducibility values for different types of abutment teeth. MATERIALS AND METHODS. To evaluate repeatability, impressions of the canine, first premolar, and first molar, prepared for ceramic crowns, were repeatedly scanned to acquire 5 sets of 3-dimensional data via stereolithography (STL) files. Point clouds were compared and the error sizes were measured (n=10, per type). To evaluate reproducibility, the impressions were rotated by 10-20° on the table and scanned. These data were compared to the first STL data and the error sizes were measured (n=5, per type). Oneway analysis of variance was used to assess the repeatability and reproducibility of the 3 types of teeth, and Tukey honest significant differences (HSD) multiple comparison test was used for post hoc comparisons (α=.05). RESULTS. The differences with regard to repeatability were 4.5, 2.7, and 3.1 μm for the canine, premolar, and molar, indicating the poorest repeatability for the canine (P

The fit of an interim implant restoration (IIR) is important for the effective treatment of patients with partial edentulism. However, no clinical trials have evaluated the marginal and internal fittings achieved with various fabrication methods.The purpose of this in vitro study was to evaluate and compare the marginal and internal discrepancies in IIRs produced with 3 different methods.Partially edentulous maxillary and mandibular casts from a transfer abutment were used. Prostheses were prepared by applying wax to the implant abutment. Shapes were copied using putty. IIRs were fabricated from poly(methyl methacrylate) for a conventional system with thermoplastic resin (CTR, n=40), a 4-axial milling machine with a crown-designed standard template library for a subtractive manufacturing system with Pekkton milling (SPM, n=40), and a 3-dimensional printer for an additive manufacturing system with digital light processing (ADL, n=40). The marginal and internal discrepancies were evaluated in each group using the silicone replica technique. The space between the abutment and the intaglio surface of the prosthesis was evaluated with a digital microscope (×160 magnification). Results were analyzed with nonparametric 2-way analysis of variance using rank-transformed values and Tukey post hoc test (α=.05).The fabricated IIRs were significantly different at all points (P.001). Moreover, ADL was superior to CTR and SPM. IIRs were significantly different only at the intermarginal discrepancy (the vertical discrepancy between the crown and the point where the margin becomes round and changes to the axial wall), the axiogingival discrepancy (the vertical discrepancy between the internal surface and the axial wall adjacent to the gingival wall of the abutment), and the occlusal discrepancy (the vertical discrepancy between the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P.001). No significant differences were found among the IIRs at the marginal discrepancy (the vertical discrepancy between the abutment margin and the crown; P.111) and the axio-occlusal discrepancy (the vertical discrepancy between the axial wall adjacent to the occlusal wall of the abutment and the internal surface; this discrepancy comprises the internal discrepancy; P.257).ADL was superior to the other 2 fabrication methods. However, all 3 methods were suitable because they produced a marginal fit which was within the clinically acceptable range.

OBJECTIVES: In South Korea (hereafter Korea), the number of adolescent offspring of immigrants has rapidly increased since the early 1990s, mainly due to international marriage. This research sought to examine the association between the experience of school violence and mental health outcomes, and the role of help-seeking behaviors in the association, among biethnic adolescents in Korea. METHODS: We analyzed cross-sectional data of 3627 biethnic adolescents in Korea from the 2012 National Survey of Multicultural Families. Based on the victim's help-seeking behavior, adolescents who experienced school violence were classified into three groups: 'seeking help' group; 'feeling nothing' group; 'not seeking help' group. Multivariate logistic regression was applied to examine the associations between the experience of school violence and depressive symptoms for males and females separately. RESULTS: In the gender-stratified analysis, school violence was associated with depressive symptoms in the 'not seeking help' (odds ratio [OR], 7.05; 95% confidence interval [CI], 3.76 to 13.23) and the 'seeking help' group (OR, 2.77; 95% CI, 1.73 to 4.44) among male adolescents after adjusting for potential confounders, including the nationality of the immigrant parent and Korean language fluency. Similar associations were observed in the female groups. However, in the 'feeling nothing' group, the association was only significant for males (OR, 8.34; 95% CI, 2.82 to 24.69), but not females (OR, 0.77; 95% CI, 0.18 to 3.28). CONCLUSIONS: This study suggests that experience of school violence is associated with depressive symptoms and that the role of victims' help-seeking behaviors in the association may differ by gender among biethnic adolescents in Korea. Language: en

An energy shell structure depending on eccentricity is analyzed in a dielectric elliptic microcavity. Through the analysis, it is explicated that the energy shell structure is governed by classical constant actions of periodic orbits. For clarification, the relation between dominances of the periodic orbits and bifurcation behaviors are obtained and the length spectra based on eigenvalues computed by a numerical method are compared with the exact lengths of the periodic orbits obtained by analytic calculations. By matching effective wave numbers obtained from the periodic orbit lengths to exact wave numbers of stationary states in closed and open cavities, we find deviations provoked from the openness. We show that these deviations are caused by additional phase factors in the Einstein-Brillouin-Keller quantization.

We elucidate that Fermi resonance ever plays a decisive role in dynamical tunneling in a chaotic billiard. Interacting with each other through an avoided crossing, a pair of eigenfunctions are coupled through tunneling channels for dynamical tunneling. In this case, the tunneling channels are an islands chain and its pair unstable periodic orbit, which equals the quantum number difference of the eigenfunctions. This phenomenon of dynamical tunneling is confirmed in a quadrupole billiard in relation with Fermi resonance.

Directional emission in a cardioid-shaped microcavity is investigated. When a microcavity laser deformed from a circular shape in polar coordinate is excited by current injection, it emits unidirectionally at a certain deformation parameter. We confirm the emission characteristics in an InGaAsP semiconductor laser.

We experimentally investigate emission characteristics of a microcavity laser, which is comprised of a half ellipse and a half circle. The emission direction of the fabricated InGaAsP semiconductor laser is unidirectional. At high injection current, the laser emits a single mode.

A Reuleaux triangle microcavity is one of the curves having a constant width. We deform it asymmetrically and compute its ray and wave properties. As a result, we find a uni-directionally emitting mode at a single window. Here, we investigate the emission mechanism and characteristics depending on the deformation.

In an asymmetric Reuleaux triangle microcavity laser, we experimentally confirm that the laser unidirectionally emits at a single window. In this shape, because the quality factor of the clockwise traveling wave is higher than that of the counter clockwise one, the clockwise traveling wave emits at a single window.

Little information is available on the translucency of zirconia-based pressable ceramic restorations with a pressed ceramic veneer and zirconia core in various thickness combinations.The purpose of this in vitro study was to assess the translucency of 3 types of zirconia-based pressable ceramics for different core-veneer thickness combinations.A bilayered ceramic specimen was prepared with a pressable ceramic (IPS e.max Zirpress, Initial IQ, Rosetta UltraPress) veneer over a zirconia core (Zenostar Zr). Three groups of specimens (n=7) were formed with the following core+veneer thicknesses: 1 +0.5 mm, 0.7 +0.8 mm, and 0.5 +1 mm. To obtain consistent thickness and high translucency, all specimens were subjected to surface grinding with a grinding machine. To eliminate the effect of differences in roughness on the translucency, the surface roughness of the ground specimens was measured with a scanning profiler, and the consistency of these measured values was verified through statistical analysis. The luminous transmittance of the specimens was measured with a spectrophotometer. The effects of the pressable ceramic type and core-veneer thickness combination on transmittance were assessed using a 2-way ANOVA (α=.05).The consistency of the surface roughness among the tested specimens was confirmed using a 1-way ANOVA and the Tukey HSD post hoc test (P.05). The luminous transmittance exhibited a statistically significant dependence on both the type of pressable ceramic and the core-veneer thickness combination (P.05).The type of pressable ceramic and core-veneer thickness combination affected the translucency of the restoration.

Statement of problem Making a computer-aided design/computer-aided manufacturing (CAD/CAM) prosthesis with a milling machine often requires 2 (2- and 1-mm diameter) or 3 (2-, 1-, and 0.6-mm diameter) burs; however, using 3 burs can reduce time effectiveness and increase cost. Studies evaluating the trueness of prostheses made with 2 and 3 burs are lacking. Purpose The purpose of this in vitro study was to evaluate the 3-dimensional trueness of crown prostheses made using 2 and 3 ball-end mill burs in the milling process. Material and methods The abutment die of the maxillary right first molar for ceramic crowns was designed with computer-aided design software. After the crown prosthesis design was completed, polyurethane blocks were milled using 2 and 3 burs with a 5-axis milling machine. The outer and inner surfaces of the milled crown prostheses were scanned with a dental scanner. The inner part was separated into a marginal part and an internal part using 3-dimensional evaluation software. The 3-dimensional trueness of the prostheses milled with 2 or 3 burs was compared. Results No significant differences in trueness were found for the inner or internal parts of the prosthesis ( P >.05). However, the outer and marginal parts of the prosthesis did show significant differences in trueness ( P Conclusions Milling the marginal part of the inner prosthesis was better with 2 burs, whereas milling the outer part was better with 3 burs.

The purpose of this study was to evaluate the shear bond strength (SBS) of veneering ceramic and zirconia fabricated by the digital veneering method.A total of 50 specimens were fabricated, i.e., 10 specimens each for the metal-ceramic (control) group and the four zirconia groups. The zirconia groups comprised specimens fabricated by the digital veneering method, the heat pressing method, and hand layering method for two groups, respectively. Furthermore, the shear bond strength was measured with a universal testing machine (Model 3345, Instron, Canton, MA, USA) and statistically analyzed using one-way ANOVA set at a significance level of P0.05. The corresponding mode of failure was determined from Scanning Electron Microscope (FESEM JSM 6701F, Jeol Ltd., Japan) observations.One-way analysis of variance (ANOVA) revealed that the metal-ceramic group had the highest SBS (43.62MPa), followed by the digital veneering method (28.29MPa), the heat pressing method (18.89MPa), and the layering method (18.65, 17.21MPa). The samples fabricated by digital veneering had a significantly higher SBS than the other zirconia samples (P0.05). All of the samples exhibited mixed failure.Veneering ceramic with a zirconia core that was fabricated via the digital veneering method is believed to be effective in clinical use since, its shear bond strength is significantly higher than that resulting from the conventional method.

The clinical applicability of CAD/CAM-fabricated zirconia copings is tested using working models made from four different highstrength Type IV gypsum materials. Each of the four materials was used to fabricate 15 zirconia copings. Precision of fit was measured with a digital electron microscope using the silicone replica technique. The mean and standard deviation of each reference point were analyzed using the one-way analysis of the variance (ANOVA) and Tukey's honest significant difference (HSD) tests (α=0.05). The overall marginal and internal fits of the zirconia copings were as follows: GS (GS: Grey Stone) group: 91.43 μm, LS (LS: Light green Stone) Group: 87.89 μm, RS (RS: Red Stone) Group: 88.75 μm, BS (BS: Beige Stone) Group: 82.78 μm. There were no significant differences between the mean adaptations of the gypsum varieties (p>0.05). This confirmed that the type of gypsum material used does not determine the precision of fit of a prosthesis.

PURPOSE. This study aimed to present the clinical applicability of restorations fabricated by a new method, by comparing the bond strength of between ceramic powder with different coefficient of thermal expansion and alloys fabricated by Selective laser sintering (SLS). MATERIALS AND METHODS. Fifty Co-Cr alloy specimens (25.0 × 3.0 × 0.5 mm) were prepared by SLS and fired with the ceramic (8.0 × 3.0 × 0.5 mm) (ISO 9693:1999). For comparison, ceramics with different coefficient of thermal expansion were used. The bond strength was measured by three-point bending testing and surfaces were observed with FE-SEM. Results were analyzed with a one-way ANOVA (α=.05). RESULTS. The mean values of Duceram Kiss (61.18 ± 6.86 MPa), Vita VM13 (60.30 ± 7.14 MPa), Ceramco 3 (58.87 ± 5.33 MPa), Noritake EX-3 (55.86 ± 7.53 MPa), and Vintage MP (55.15 ± 7.53 MPa) were found. No significant difference was observed between the bond strengths of the various metal-ceramics. The surfaces of the specimens possessed minute gaps between the additive manufactured layers. CONCLUSION. All the five powders have bond strengths higher than the required 25 MPa minimum (ISO 9693); therefore, various powders can be applied to metal structures fabricated by SLS. [J Adv Prosthodont 2015;7:312-6]

In this paper, we analyze the performance of feed forward neural network (FFNN)-based language model in contrast with n-gram. The probability of n-gram language model was estimated based on the statistics of word sequences. The FFNN-based language model was structured by three hidden layers, 500 hidden units per each hidden layer, and 30 dimension word embedding. The performance of FFNN-based language model is better than that of n-gram by 1.5 % in terms of WER on the English WSJ domain.

This paper proposes a voice QR code for mobile devices. The QR code shows great performance for error correction and recovers decoding errors caused by skewed image angle or luminosity. In order to correct an image shot of the QR code symbol, a complex error code and data map need to be generated. Additionally, there is a need for an efficient QR code format and an audio codec for voice interface. This paper presents the generation method of the complex error code and data map in the voice QR code and suggests the efficient QR code format and an audio codec for voice interface.

This paper proposes a learning speed improvement using multi-GPUs on DNN-based acoustic model training in Korean intelligent personal assistant (IPA). DNN learning involves iterative, stochastic parameter updates. These updates depend on the previous updates. The proposed method provides a distributed computing for DNN learning. DNN-based acoustic models are trained by using 320 h length Korean speech corpus. It was shown that the learning speed becomes five times faster on this implementation while maintaining speech recognition rate.

This book covers state-of-the-art topics on the practical implementation of Spoken Dialog Systems and intelligent assistants in everyday applications. It presents scientific achievements in language processing that result in the development of successful applications and addresses general issues regarding the advances in Spoken Dialog Systems with applications in robotics, knowledge access and communication. Emphasis is placed on the following topics: speaker/language recognition, user modeling / simulation, evaluation of dialog system, multi-modality / emotion recognition from speech, speech data mining, language resource and databases, machine learning for spoken dialog systems and educational and healthcare applications.

The object of this research is to enhance the damping performance for vibration suppression of rotating composite thin-walled beams using MFC actuators and PVDF sensors. The formulation is based on single cell composite beam including a warping function, centrifugal force, Coriolis acceleration and piezoelectric effect. Adaptive capability of the beam is acquired through the use of a negative velocity feedback control algorithm. Numerical analysis is performed using finite element method and Newmark time integration method is used to calculate the time response of the model. It is observed that the feedback control gain has an effect on damping performance. The paper continues with an investigation into influences of parameters such as the rotating speed and the fiber orientation in host structures. Also, it is confirmed that effective damping performance is achievable through the suitable arrangement and distributed size of sensor and actuator pair using case study.

Deployment of a multi-link beam structure undergoing locking is analyzed in the Timoshenko beam theory. In the modeling of the system, dynamic forces are assumed to be torques and restoring forces due to the torsion spring at each joint. Hamilton's principle is used to determine the equations of motion and the finite element method is adopted to analyze the system. Newmark time integration and Newton–Raphson iteration methods are used to solve for the non-linear equations of motion at each time step. The locking at the joints of the multi-link flexible structure is analyzed by the momentum balance method. Numerical results are compared with the previous experimental data. The angles and angular velocities of each joint, tip displacement, and velocity of each link are investigated to study the motions of the links at each time step. To analyze the effect of thickness on the motion of the link, the angle and the tip displacement of each link are compared according to the various slenderness ratios. Additionally, in order to investigate the effect of shear, the tip displacements of a Timoshenko beam are compared with those of an Euler–Bernoulli beam.

Three-dimensional thermomechanical buckling analysis is investigated for functionally graded composite structures that composed of ceramic, functionally graded material (FGM), and metal layers. Material properties are assumed to be temperature dependent, and in FGM layer, they are varied continuously in the thickness direction according to a simple power law distribution in terms of the ceramic and metal volume fractions. The finite element model is adopted by using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. Temperature at each node is obtained by solving the thermomechanical equations. For a time discretization, Crank–Nicolson method is used. In numerical results, the thermal buckling behavior of FGM composite structures due to FGM thickness ratios, volume fraction distributions, and system geometric parameters are analyzed.

Three-dimensional thermal buckling and postbuckling analyses of functionally graded materials subjected to uniform or non-uniform temperature rise are examined by using finite element method. Material properties are varied continuously in the thickness direction according to a simple power law distribution. For more accurate modeling of material properties and temperature field in the thickness direction, a three-dimensional solid element is used. The Green-Lagrange nonlinear strain-displacement relation is used to account for large deflection due to thermal load and the incremental formulation is applied for nonlinear analysis. The thermal loads are assumed as uniform, linear and sinusoidal temperature rise across the thickness. Numerical results are compared with those of previous works. Furthermore, the thermal buckling and postbuckling behaviors due to temperature field, volume fraction distributions, and system geometric parameters are studied, in detail.