• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.1833-1848
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• 2022

Named entity recognition (NER) is an important basic task in the field of Natural Language Processing (NLP). Recently deep learning approaches by extracting word segmentation or character features have been proved to be effective for Chinese Named Entity Recognition (CNER). However, since this method of extracting features only focuses on extracting some of the features, it lacks textual information mining from multiple perspectives and dimensions, resulting in the model not being able to fully capture semantic features. To tackle this problem, we propose a novel Multi-view Semantic Feature Fusion Model (MSFM). The proposed model mainly consists of two core components, that is, Multi-view Semantic Feature Fusion Embedding Module (MFEM) and Multi-head Self-Attention Mechanism Module (MSAM). Specifically, the MFEM extracts character features, word boundary features, radical features, and pinyin features of Chinese characters. The acquired font shape, font sound, and font meaning features are fused to enhance the semantic information of Chinese characters with different granularities. Moreover, the MSAM is used to capture the dependencies between characters in a multi-dimensional subspace to better understand the semantic features of the context. Extensive experimental results on four benchmark datasets show that our method improves the overall performance of the CNER model.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.407-412
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• 2021

Purpose: The purpose of this study was to evaluate the accuracy of virtual 3-dimensional (3D) cephalograms constructed using the principle of biplanar radiography by comparing them with cone-beam computed tomography (CBCT) images. Materials and Methods: Thirty orthodontic patients were enrolled in this study. Frontal and lateral cephalograms were obtained with the use of a head posture aligner and reconstructed into 3D cephalograms using biplanar radiography software. Thirty-four measurements representing the height, width, depth, and oblique distance were computed in 3 dimensions, and compared with the measurements from the 3D images obtained by CBCT, using the paired t-test and Bland-Altman analysis. Results: Comparison of height, width, depth, and oblique measurements showed no statistically significant differences between the measurements obtained from 3D cephalograms and those from CBCT images (P>0.05). Bland-Altman plots also showed high agreement between the 3D cephalograms and CBCT images. Conclusion: Accurate 3D cephalograms can be constructed using the principle of biplanar radiography if frontal and lateral cephalograms can be obtained with a head posture aligner. Three-dimensional cephalograms generated using biplanar radiography can replace CBCT images taken for diagnostic purposes.

• Bulletin of the Society of Naval Architects of Korea
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• v.12 no.2
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• pp.59-66
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• 1975

Recently, as the dimensions of energy carriers increase, especially in draft, a reliable prediction of the ship motions at finite depths of water becomes necessary. The purpose of this paper is to probe the effect of finite water depth on the hydrodynamic forces and ship motions, particularly heave and pitch, in longitudinal regular head waves, by comparing the experimental value of Freakes and Keay with the author's theoretical value obtained by applying the modified strip theory to the Mariner class ship. It is confirmed that generally the hydrodynamic coefficients in the equations of motion increase with decreasing water depth, and the wave exciting forces and moments decrease with decreasing water depth. Amplitudes of heave and pitch in longitudinal regular head waves decrease as the water depth in the range where the length of the incident wave is comparatively long. The effects of Froude Number on the hydrodynamic coefficients increase with decreasing water depth and is more noticeable in the case of heave than pitch. In heave, generally the discrepancy between the experimental value and the theoretical value is relatively small in the case of $F_n=O$, but it is very large in the case of $F_n=0.2$. It is considered that the trend stems from the ignorance of the three dimensional effect and the other effects due to shallowness of water on the hydrodynamic coefficients in the theoretical calculation. An extension of methods for calculating the two dimensional hydrodynamic forces to included the effect of forward speed should be recommended. It is required that more experimental works in finite water depths will be carried out for correlation studies between the theoretical calculation, according tp modified strip theory, and model experiments.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.374-378
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• 1997

Operative procedures such as core drilling with and without fibular bone grafting have been recognized as the treatment methods for osteonecrosis of femoral head(ONFH) by delaying or preventing the collapse of the femoral head. In addition, core drilling with cementation using polymethylmethacrylate (PMMA) has been proposed recently as another surgical method. However, no definite treatment modality has been found yet while operative procedures remain controversial to many clinicians In this study, a finite element method(FEM) was employed to analyze and compare various surgical procedures of ONFH to provide a biomechanical insight. This study was based upon biomechanical findings which suggest stress concentration within the femoral head may facilitate the progression of the necrosis and eventual collapse. For this purpose, five anatomically relevant hip models were constructed in three dimensions : they were (1) intact(Type I), (2) necrotic(Type II), (3) core drilled only(Type III), (4) core drilled with fibular bone graft(Type IV), and (5) core drilled with cementation(Type V). Physiologically relevant loading were simulated. Resulting stresses were calculated. Our results showed that the volumetric percentage subjected to high stress in the necrotic cancellous region was greatest in the core drilled only model(Type III), followed by the necrotic(Type II), the bone graft (Type IV), and the cemented(Type V) models. Von Mises stresses at the tip of the graft(Type IV) was found to be twice more than those of cemented core(Type V) indicating the likelihood of the implant failure. In addition, stresses within the cemented core(Type V) were more evenly distributed and relatively lower than within the fibular bone graft(Type IV). In conclusion, our biomechanical analyses have demonstrated that the bone graft method(Type IV) and the cementation method(Type V) are both superior to the core decompression method(Type III) by reducing the high stress regions within the necrotic cancellous bone. Also it was found that the core region filled with PMMA(Type V) provides far smoother transfer of physiological load without causing the concentration of malignant stresses which may lead to the failure than with the fibular bone graft(Type IV). Therefore, considering the above results along with the degree of difficulties and risk of infection involved with preparation of the fibular bone graft, the cementation method appears to be a promising surgical treatment for the early stage of osteonecrosis of the femoral head.

• Imaging Science in Dentistry
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• v.50 no.3
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• pp.227-236
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• 2020

Purpose: Image artifacts caused by patient motion cause problems in cone-beam computed tomography (CBCT) because they lead to distortion of the 3-dimensional reconstruction. This prospective study was performed to quantify patient movement during CBCT acquisition and its influence on image quality. Materials and Methods: In total, 412 patients receiving CBCT imaging were equipped with a wireless head sensor system that detected inertial, gyroscopic, and magnetometric movements with 6 dimensions of freedom. The type and amplitude of movements during CBCT acquisition were evaluated and image quality was rated in 7 different anatomical regions of interest. For continuous variables, significance was calculated using the Student t-test. A linear regression model was applied to identify associations of the type and extent of motion with image quality scores. Kappa statistics were used to assess intra- and inter-rater agreement. Chi-square testing was used to analyze the impact of age and sex on head movement. Results: All CBCT images were acquired in a 10-month period. In 24% of the investigations, movement was recorded (acceleration: >0.10 [m/s²]; angular velocity: >0.018 [°/s]). In all examined regions of interest, head motion during CBCT acquisition resulted in significant impairment of image quality (P<0.001). Movement in the horizontal and vertical axes was most relevant for image quality (R²>0.7). Conclusion: Relevant head motions during CBCT imaging were frequently detected, leading to image quality loss and potentially impairing diagnosis and therapy planning. The presented data illustrate the need for digital correction algorithms and hardware to minimize motion artefacts in CBCT imaging.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.89-94
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• 2002

n general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.591-596
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• 2002

Fused deposition(FD) modeling by Stratasys Inc., is one of the material deposition subfamilies of solid freefrom fabrication(SFF) technologies. In this process, build material in the form of a flexible filament, is heated to a semi-liquid state and extruded from a controlled deposition head onto a fixtureless table in a temperature controlled environment. The position of nozzle is computer controlled relative to the base, which allows geometric complex models to be made to precise dimensions. FDM provide what the part was directly tested by the worker. It provide believable data. This Study is identify to surface roughness by build orientation adjustment. So, the paper is the study on surface roughness by build orientation at FDM.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.387-392
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• 2001

Fused deposition(FD) modeling by Stratasys Inc., is one of the material deposition subfamilies of solid freeform fabrication(SFF) technologies. In this process, build material in the form of a flexible filament, is heated to a semi-liquid state and extruded from a robotically controlled deposition head onto a fixtureless table in a temperature controlled environment. The position of nozzle is computer controlled relative to the base, which allows geometric complex models to be made to precise dimensions. FDM provide what the part was directly tested by the worker. It provide believable data. This study is experiment on surface roughness of part at FDM

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.597-600
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• 2002

In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Uneven flow distribution can also increase or decrease the power consumption with a change in total developed head. To avoid these sump problems pump station designers are considered intake structure dimensions, such as approaching upstream, baffle size, sump width, width of pump cell and so on. From this background, flow characteristics of intake within sump are Investigated numerically to obtain the optimal sump design data. The sump model is designed in accordance with HI code.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.10 s.103
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• pp.1211-1216
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• 2005

Underwater acoustic transducers are widely used for SONAR application, whose important design parameters are shapes. materials, dimensions and supporting structures. Practical design method of transducers consists of manufacturing, experiments and modifications so that it requires much time and expenses. In this study, an analytical method was developed for the Tonpilz type transducers using the commercial finite element analysis code ATILA which can solve the electro-mechanical coupling problems. A finite element model was established including the transducer elements such as ceramic stack, head mass, tail mass, tensile bolt, and molding layers. The proposed model was verified and modified by comparing the in-air and in-water test results of prototypes. The developed analysis method will be effectively used for the sensitivity analysis of design parameters in transducer design process.