• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.1-2
• /
• 2012

Active process of industrialization of near-earth space assumes design and development of high effective propulsion systems with a small thrust. The specific place among propulsion systems with a small thrust is taken the propulsion systems with use of electrical propulsion thrusters (EPT).

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.04a
• /
• pp.129-136
• /
• 1999

This research proposes an effective analytical methodology for vertical vibration of three dimensional frame structures including slabs. The consideration of slabs, although allows more precise results, requires large amount of computer time and memory space due to the use of plane stress elements. In consideration of these problems, a method to properly manage nodal points and degrees of freedom is proposed based on matrix condensation technique. Also studied is the use of substructure method to obtain fast and reliable results with simple input data when they are applied to conventional building structures.

• Structural Engineering and Mechanics
• /
• v.29 no.3
• /
• pp.289-300
• /
• 2008

The use of metric trial functions to represent the real stress field in what is called the unsymmetric finite element formulation is an effective way to improve predictions from distorted finite elements. This approach works surprisingly well because the use of parametric functions for the test functions satisfies the continuity conditions while the use of metric (Cartesian) shape functions for the trial functions attempts to ensure that the stress representation during finite element computation can retrieve in a best-fit manner, the actual variation of stress in the metric space. However, the issue of how to handle situations where there is locking along with mesh distortion has never been addressed. In this paper, we show that the use of a consistent definition of the constrained strain field in the metric space can ensure a lock-free solution even when there is mesh distortion. The three-noded Timoshenko beam element is used to illustrate the principles. Some significant conclusions are drawn regarding the optimal strategy for finite element modelling where distortion effects and field-consistency requirements have to be reconciled simultaneously.

• Proceedings of the KSRS Conference
• /
• 2007.10a
• /
• pp.337-340
• /
• 2007

Many researches conducted to investigate the relationship between surface emissivity and surface temperature in the past two decades and pointed out that the emissivity play a key role in applying remote sensing data to retrieve surface temperature. The task of surface temperature estimation is so important in many research fields, such as earth energy budgets, evapotranspiration, drought, global change and heat island effect. Therefore, it is indispensable to develop an effective and accurate technique to estimate the emissivity for accurate surface temperature estimations. This study developed an improved emissivity estimation technique for the use of surface temperature retrievals with MODIS data. The result of applying this improved technique using Band 31 of MODIS shows that the accuracy of estimated surface temperatures will be improved. This study also uses MODIS data observed in 2005 to establish the relationship between the surface emissivity correction factor and NDVI. Through the use of these correction factors, the land surface temperature can be retrieved more accurate with MODIS data.

• The Korean Journal of Applied Statistics
• /
• v.30 no.4
• /
• pp.555-566
• /
• 2017

For multivariate datasets with large number of variables, classical dimensional reduction methods such as principal component analysis may not be effective for data visualization. The underlying reason is that the dimensionality of the space of variables is often larger than two or three, while the visualization to the human eye is most effective with two or three dimensions. This paper proposes a working procedure which first partitions the variables into several "latent" clusters, explores individual data subsets, and finally integrates findings. We use R pakacage "ClustOfVar" for partitioning variables around latent dimensions and the principal component biplot method to visualize within-cluster patterns. Additionally, we use the technique for embedding supplementary variables to figure out the relationships between within-cluster variables and outside variables.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.5
• /
• pp.1-10
• /
• 2010

The aims of this study is to analyze that the double-skinned outer surface of building will be the effective measure to improve the use of space and save energy through the evaluation of the buildings renovation. In other words, it is significantly effective to increase the insulation of the outer surface where the most heat loss occurs; it is also energy-saving to convert the space created by pilotis in the southern and northern parts of the buildings into an double-skinned atrium. Research methods of this study are consisted with two steps, situation analysis and simulation analysis. IRISYS 1000 Series Imager was used for research of situation analysis and Visual DOE 4.0 was used for simulation analysis with the 1st Buildings of Jeju Special self-Governing Province. As results of simulation, it was proved that Double skin Method is more effective for green building than basic model. it was predicted to save 8.6% of energy by Double skin Method. Especially, in case of using of ventilation within double-skinned atrium, it was predicted that saving of energy was most effective than other method.

• International Journal of Computer Science & Network Security
• /
• v.23 no.5
• /
• pp.33-40
• /
• 2023

The mainstay of current image recovery frameworks is Content-Based Image Retrieval (CBIR). The most distinctive retrieval method involves the submission of an image query, after which the system extracts visual characteristics such as shape, color, and texture from the images. Most of the techniques use RGB color space to extract and classify images as it is the default color space of the images when those techniques fail to change the color space of the images. To determine the most effective color space for retrieving images, this research discusses the transformation of RGB to different color spaces, feature extraction, and usage of Convolutional Neural Networks for retrieval.

• Journal of Chest Surgery
• /
• v.22 no.5
• /
• pp.851-856
• /
• 1989

Initial successful treatment of postpneumonectomy empyema depends to a large extent on adequate dependent drainage of the empyema sac and the use of antibiotics. But definite control of the infected space remains a disturbing and controversial area in the field of thoracic surgery. A 55-year-old man had a right pneumonectomy for tuberculosis with the development of postoperative thoracic empyema and in October 1973. Postoperatively, an empyema developed and the condition was managed with closed drainage and an open window thoracostomy. He was transferred to our institution in October 1988, and underwent thoracoplasty for the obliteration of the empyema space, resulting in a remaining space. The remaining space after thoracoplasty was obliterated by myoplasty using a rotation flap of splitted pectoralis major muscle three months later. He was discharged with uneventful course 12 days after operation, and continues to do well 3 months following operation. Our experience shows that thoracoplasty and myoplasty offer an effective alternative method of management of post-pneumonectomy empyema.

• Journal of Astronomy and Space Sciences
• /
• v.33 no.4
• /
• pp.279-285
• /
• 2016

The space radiation dose over air routes including polar routes should be carefully considered, especially when space weather shows sudden disturbances such as coronal mass ejections (CMEs), flares, and accompanying solar energetic particle events. We recently established a heliocentric potential (HCP) prediction model for real-time operation of the CARI-6 and CARI-6M programs. Specifically, the HCP value is used as a critical input value in the CARI-6/6M programs, which estimate the aviation route dose based on the effective dose rate. The CARI-6/6M approach is the most widely used technique, and the programs can be obtained from the U.S. Federal Aviation Administration (FAA). However, HCP values are given at a one month delay on the FAA official webpage, which makes it difficult to obtain real-time information on the aviation route dose. In order to overcome this critical limitation regarding the time delay for space weather customers, we developed a HCP prediction model based on sunspot number variations (Hwang et al. 2015). In this paper, we focus on improvements to our HCP prediction model and update it with neutron monitoring data. We found that the most accurate method to derive the HCP value involves (1) real-time daily sunspot assessments, (2) predictions of the daily HCP by our prediction algorithm, and (3) calculations of the resultant daily effective dose rate. Additionally, we also derived the HCP prediction algorithm in this paper by using ground neutron counts. With the compensation stemming from the use of ground neutron count data, the newly developed HCP prediction model was improved.

• Smart Structures and Systems
• /
• v.15 no.4
• /
• pp.949-961
• /
• 2015

The goal of this study is to present numerical modeling and analytical testing in order to evaluate an innovative space truss typed temporary structure, which is used to maintenance and repair of road tunnels. The present space truss structure has merits to use UL-700 high strength steel tube as members and to carry out maintenance and repair works of road tunnels without blocking cars and transportations. Numerical modeling and analytical testing of the space truss are investigated by using commercial engineering software, i.e., ABAQUS 6.5-1, and then it is verified that the truss structure has both structural safety and effective function for maintenances and repairs of road tunnels.