• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6019-6023
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• 2013

Lung cancer, one of the leading causes of cancer-related deaths, usually appears as solitary pulmonary nodules (SPNs) which are hard to diagnose using the naked eye. In this paper, curvelet-based textural features and clinical parameters are used with three prediction models [a multilevel model, a least absolute shrinkage and selection operator (LASSO) regression method, and a support vector machine (SVM)] to improve the diagnosis of benign and malignant SPNs. Dimensionality reduction of the original curvelet-based textural features was achieved using principal component analysis. In addition, non-conditional logistical regression was used to find clinical predictors among demographic parameters and morphological features. The results showed that, combined with 11 clinical predictors, the accuracy rates using 12 principal components were higher than those using the original curvelet-based textural features. To evaluate the models, 10-fold cross validation and back substitution were applied. The results obtained, respectively, were 0.8549 and 0.9221 for the LASSO method, 0.9443 and 0.9831 for SVM, and 0.8722 and 0.9722 for the multilevel model. All in all, it was found that using curvelet-based textural features after dimensionality reduction and using clinical predictors, the highest accuracy rate was achieved with SVM. The method may be used as an auxiliary tool to differentiate between benign and malignant SPNs in CT images.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.2
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• pp.109-120
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• 2007

Auxiliary support systems such as the reinforced protective umbrella method have been applied before tunnel excavation to increase ground stiffness and to prevent the large deformation. However, determination procedure of geotechnical parameters along the construction sequence contains various errors. This study suggests a method to characterize the time-dependent behavior of pre-reinforced zones around the tunnel using elastic waves. Experimental results show that shear strength as well as elastic wave velocities increase with the curing time. Shear strength and strength parameters can be uniquely correlated to elastic wave velocities. Obtained results from the laboratory tests are applied to numerical simulation of tunnel considering its construction sequences. Based on numerical analysis, initial installation part of pre-reinforcement and portal of tunnel are critical for tunnel stability. Result of the time-dependent condition is similar to the results of for $1{\sim}2$ days of the constant time conditions. Finally, suggested simple analysis method combining experimental and numerical procedure which considering time-dependent behavior of pre-reinforced zone on tunnel would provide reliable and reasonable design and analysis for tunnel.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.240-240
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• 2011

The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. A first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR core plasmas. Performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a JAEA magnetic bucket plasma generator with multi-pole cusp fields and a set of KAERI prototype-III tetrode accelerators with circular apertures. The inner volume of plasma generator and accelerator column in the LPIS-1 is approximately 123 liters. Final design requirements for the ion source were a 120 kV/ 65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called as an arc-beam extraction method. A stable ion beam extraction of LPIS-1 has been achieved up to an 100 kV/42 A for a 4 s pulse length and an 80 kV/25 A for a 14 s pulse length. Optimum beam perveance of 1.21 microperv has been found at an accelerating voltage of 80 kV. Neutralization efficiency has been measured by using a water flow calorimetry (WFC) method of calorimeter and an operation of bending magnet. The full-energy species of ion beams have been detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6~1.1 A/kW depending on the operating conditions of arc discharge.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.7
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• pp.291-298
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• 2022

In this paper, we present a method for dependency parsing with chunking in Korean. Dependency parsing is a task of determining a governor of every word in a sentence. In general, we used to determine the syntactic governor in Korean and should transform the syntactic structure into semantic structure for further processing like semantic analysis in natural language processing. There is a notorious problem to determine whether syntactic or semantic governor. For example, the syntactic governor of the word "먹고 (eat)" in the sentence "밥을 먹고 싶다 (would like to eat)" is "싶다 (would like to)", which is an auxiliary verb and therefore can not be a semantic governor. In order to mitigate this somewhat, we propose a Korean dependency parsing after chunking, which is a process of segmenting a sentence into constituents. A constituent is a word or a group of words that function as a single unit within a dependency structure and is called a chunk in this paper. Compared to traditional dependency parsing, there are some advantage of the proposed method: (1) The number of input units in parsing can be reduced and then the parsing speed could be faster. (2) The effectiveness of parsing can be improved by considering the relation between two head words in chunks. Through experiments for Sejong dependency corpus, we have shown that the USA and LAS of the proposed method are 86.48% and 84.56%, respectively and the number of input units is reduced by about 22%p.

• Journal of Broadcast Engineering
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• v.26 no.6
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• pp.692-703
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• 2021

Recently, with the development of computer graphics technology, research on technology for expressing real objects as more realistic virtual graphics is being actively conducted. Point cloud is a technology that uses numerous points, including 2D spatial coordinates and color information, to represent 3D objects, and they require huge data storage and high-performance computing devices to provide various services. Video-based Point Cloud Compression (V-PCC) technology is currently being studied by the international standard organization MPEG, which is a projection based method that projects point cloud into 2D plane, and then compresses them using 2D video codecs. V-PCC technology compresses point cloud objects using 2D images such as Occupancy map, Geometry image, Attribute image, and other auxiliary information that includes the relationship between 2D plane and 3D space. When increasing the density of point cloud or expanding an object, 3D calculation is generally used, but there are limitations in that the calculation method is complicated, requires a lot of time, and it is difficult to determine the correct location of a new point. This paper proposes a method to generate additional points at more accurate locations with less computation by applying 2D interpolation to the image on which the point cloud is projected, in the V-PCC technology.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.217-228
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• 2023

Video instance segmentation is an intelligent visual task with high complexity because it not only requires object instance segmentation for each image frame constituting a video, but also requires accurate tracking of instances throughout the frame sequence of the video. In special, human instance segmentation in drama videos has an unique characteristic that requires accurate tracking of several main characters interacting in various places and times. Also, it is also characterized by a kind of the class imbalance problem because there is a significant difference between the frequency of main characters and that of supporting or auxiliary characters in drama videos. In this paper, we introduce a new human instance datatset called MHIS, which is built upon drama videos, Miseang, and then propose a novel video data augmentation method, CDVA, in order to overcome the data imbalance problem between character classes. Different from the previous video data augmentation methods, the proposed CDVA generates more realistic augmented videos by deciding the optimal location within the background clip for a target human instance to be inserted with taking rich spatio-temporal context embedded in videos into account. Therefore, the proposed augmentation method, CDVA, can improve the performance of a deep neural network model for video instance segmentation. Conducting both quantitative and qualitative experiments using the MHIS dataset, we prove the usefulness and effectiveness of the proposed video data augmentation method.

• Fire Science and Engineering
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• v.31 no.3
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• pp.106-118
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• 2017

The purpose of this study was to realize volunteer fire departments' historical identity through a review of the transition process from the quickening period of volunteer fire departments to the enactment of the volunteer fire department act in 2014, establish it newly from the viewpoint of changing the basic theoretical concepts, and seek a development plan. For this, the technical approach method was used based on the research method of literature searches. The result of the study established the definition as 'volunteer fire departments are legal auxiliary organizations composed by local residents who volunteer and understand one another with their independent and voluntary will to prepare for all kinds of disasters as well as fire suppression, rescue, and first aid.' and the installation ideology as 'leading service organizations of safety as a form of community involvement', 'resident-friendly organizational activities based on autonomous operational operation' and 'the activities of supplementing their demands according to the realization of social welfare and regional conditions'. Regarding the characteristics, the basic theoretical concept was newly established by 'voluntary participation', 'social expandability', 'the realization and complementation of social welfare', and 'professionalism and possibilities'. In addition it is expected that the results of this study can be utilized as the basic materials in studies of volunteer fire departments in the future.

• Journal for History of Mathematics
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• v.19 no.1
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• pp.65-78
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• 2006

The law of refraction, which is called Snell's law in physics, has a significant meaning in mathematics history. After Snell empirically discovered the refraction law $\frac{v_1}{sin{\theta}_1}=\frac{v_2}{sin{\theta}_2$ through countless observations, many mathematicians endeavored to deduce it from the least time principle, and the need to surmount these difficulties was one of the driving forces behind the early development of calculus by Leibniz. Fermat solved it far advance of others by inventing a method that eventually led to the differential calculus. Historically, mathematics has developed in close connection with physics. Physics needs mathematics as an auxiliary discipline, but physics can also belong to the lived-through reality from which mathematics is provided with subject matters and suggestions. The refraction law is a suggestive example of interrelations between mathematical and physical theories. Freudenthal said that a purpose of mathematics education is to learn how to apply mathematics as well as to learn ready-made mathematics. I think that the refraction law could be a relevant content for this purpose. It is pedagogically sound to start in high school with a quasi-empirical approach to refraction. In college, mathematics and physics majors can study diverse mathematical proof including Fermat's original method in the context of discussing the phenomenon of refraction of light. This would be a ideal environment for such pursuit.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.306-309
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• 2005

One of the most critical issues in sol id oxide fuel cell (SOFC)running on hydrocarbon fuels is the risk of carbon formation from the fuel gas. The simple method to reduce the risk of carbon formation from the reactions is to add steam to the fuel stream, leading to the carbon gasification react ion. However, the addition of steam to fuel is not appropriate for the auxiliary power unit (APU) and potable power generation (PPG) systems due to an increase of complexity and bulkiness. In this regard, many researchers have focused on so-called 'direct methane' operation of SOFC, which works with dry methane without coking. However, coking can be suppressed only by the operation with a high current density, which may be a drawback especially for the APU and PPG systems. The single chamber fuel cell (SC-SOFC) is a novel simplification of the conventional SOFC into which a premixed fuel/air mixture is introduced. It relies on the selectivity of the anode and cathode catalysts to generate a chemical potential gradient across the cell. Moreover it allows compact and seal-free stack design. In this study, we fabricated honeycomb type mixed-gas fuel cell (MGFC) which has advantages of stacking to the axial direction and increasing volume power density. Honeycomb-structured SOFC with four channels was prepared by dry pressing method. Two alternative channels were coated with electrolyte and cathode slurry in order to make cathodic reaction sites. We will discuss that the anode supported honeycomb type cell running on mixed gas condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.27-37
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• 1983

A method of dynamic analysis is developed for torsional free vibrations of elliptical-box girder type or stiffening truss system suspension bridge. In this study, the method based on a finite element technique using a digital computer, is illustrated by two numerical examples, the Namhae Bridge which is located in Kyungsang nam-do opened on June, 1973, and the Mt. Chunma Bridge is simple span pedestrian's suspension bridge with lateral bracing system in Mt. Chunma, Kyungki-do, are used. In general, dynamic modes of complex suspension bridges are three-dimensional in form, i.e., coupling between vertical and torsional motions. However, introduced that amplitudes of oscillation are infinitesimal for coincidence with the purpose of it's use, thereupon, the torsional vibration analyses are treated without coupling terms. A sufficient number of natural frequencies and mode shapes for torsional free vibration are presented in this paper. In the case of Mt. Chunma Bridge, the natural frequencies and periods are computed with and without reinforcement, respectively, and compared their discrepancies. The influence of the auxiliary reinforcing cables is prevailing in the first few modes, namely, 1st and 2nd in symmetric and 1st, 2nd and 3rd in antisymmetric vibration, and conspicuous in the symmetric compared with the antisymmetric motion, but in the higher modes, this kind of simple accessory elucidates rether converse effects. In the Namhae Bridge, the results are compared with the Manual's obtained by wind tunnel test. It reveals commendable agreement.