• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.942-948
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• 2021

The aim of this work is to help inform the decision for choosing a convenient material for the PGAA (Prompt Gamma Activation Analysis) collimator plug to be installed at the tangential channel of the Moroccan Triga Mark II Research Reactor. Two families of materials are usually used for collimator construction: a mixture of high-density polyethylene (HDPE) with boron, which is commonly used to moderate and absorb neutrons, and heavy materials, either for gamma absorption or for fast neutron absorption. An investigation of two different collimator designs was performed using N-Particle Monte Carlo MCNP6.2 code with the ENDF/B-VII.1 and MCLIP84 libraries. For each design, carbon steel and lead materials were used separately as collimator heavy materials. The performed study focused on both the impact on neutron beam quality and the neutron-gamma background at the exit of the collimator beam tube. An analysis and assessment of the principal findings is presented in this paper, as well as recommendations.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.359-364
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• 2021

In recent years Hadoop usage has been increasing day by day. The need of development of the technology and its specified outcomes are eagerly waiting across globe to adopt speedy access of data. Need of computers and its dependency is increasing day by day. Big data is exponentially growing as the entire world is working in online mode. Large amount of data has been produced which is very difficult to handle and process within a short time. In present situation industries are widely using the Hadoop framework to store, process and produce at the specified time with huge amount of data that has been put on the server. Processing of this huge amount of data having small files & its storage optimization is a big problem. HDFS, Sequence files, HAR, NHAR various techniques have been already proposed. In this paper we have discussed about various existing techniques which are developed for accessing and storing small files efficiently. Out of the various techniques we have specifically tried to implement the HDFS- HAR, NHAR techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7A
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• pp.641-650
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• 2002

Space-Time Block Code(STBC) provides full diversity gains with simple linear processing at the receiver. Interference Cancellation(IC) techniques in system using STBC improve the capacity and performance of wireless systems with co-channel users. Various IC techniques, Minimum Mean-Squared Error(MMSE) and Zero-Forcing(ZF) algorithms in system with STBC were proposed in the literatures in multiuser environment. The performance of these IC techniques were simulated by assuming perfect channel state information(CSI) of multiuser at the receiver. However, in practice it is difficult to know perfect CSI of multiuser at the receiver. Thus, channel estimation scheme is essential at the receiver. Also SNR estimation scheme is required to operate the MMSE IC algorithm. In this paper, we present estimation schemes of CSI and SNR using training sequences. Through extensive computer simulation, we compare and evaluate the performance of IC techniques using the proposed CSI and SNR estimation techniques.

• Geomechanics and Engineering
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• v.38 no.1
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• pp.29-44
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• 2024

This research investigates the effectiveness of data augmentation techniques in the automated analysis of B-scan images from ground-penetrating radar (GPR) using deep learning. In spite of the growing interest in automating GPR data analysis and advancements in deep learning for image classification and object detection, many deep learning-based GPR data analysis studies have been limited by the availability of large, diverse GPR datasets. Data augmentation techniques are widely used in deep learning to improve model performance. In this study, we applied four data augmentation techniques (geometric transformation, color-space transformation, noise injection, and applying kernel filter) to the GPR datasets obtained from a testbed. A deep learning model for GPR data analysis was developed using three models (Faster R-CNN ResNet, SSD ResNet, and EfficientDet) based on transfer learning. It was found that data augmentation significantly enhances model performance across all cases, with the mAP and AR for the Faster R-CNN ResNet model increasing by approximately 4%, achieving a maximum mAP (Intersection over Union = 0.5:1.0) of 87.5% and maximum AR of 90.5%. These results highlight the importance of data augmentation in improving the robustness and accuracy of deep learning models for GPR B-scan analysis. The enhanced detection capabilities achieved through these techniques contribute to more reliable subsurface investigations in geotechnical engineering.

• Journal of Sensor Science and Technology
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• v.17 no.6
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• pp.406-413
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• 2008

We have been implemented simple statistical pattern recognition methods for harmful gases classification using gas sensors array fabricated by MEMS (Micro Electro Mechanical System) technology. The performance of pattern recognition method as a gas classifier is highly dependent on the choice of pre-processing techniques for sensor and sensors array signals and optimal classification algorithms among the various classification techniques. We carried out pre-processing for each sensor's signal as well as sensors array signals to extract features for each gas. We adapted simple statistical pattern recognition algorithms, which were PCA (Principal Component Analysis) for visualization of patterns clustering and MLR (Multi-Linear Regression) for real-time system implementation, to classify harmful gases. Experimental results of adapted pattern recognition methods with pre-processing techniques have been shown good clustering performance and expected easy implementation for real-time sensing system.

• Journal of the Korean Society for Advanced Composite Structures
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• v.7 no.1
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• pp.45-52
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• 2016

There are only 10 projects of the domestic greenhouse gas(GHG) emissions trading scheme in building sector (i.e., 1.5% of 652 registered projects) because the certified methodologies to reduce GHG emissions can not be applied to building sector. This study presents remodeling techniques to reduce GHG emissions in existing buildings. First of all, preconditions and related regulations were reviewed. And then, a pool of factors for GHG reduction are selected and evaluated with respect to factors for reducing energy consumption. This study also investigates the criteria and the decision making process for remodeling techniques to reduce GHG emissions. Finally, the remodeling techniques using the decision making process were grouped based on redundancy of each effect. If reducing methodologies for GHG offset program can be developed using the analyzed remodeling techniques in this study, registered projects in building sector would be increase.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.38-51
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• 2000

This study seeks to present creation techniques increasing biodiversity while excluding techniques that avoid rooftop as a place for revegetation or techniques that are standardized and ecologically undesirable. To this end, a theoretical study was conducted including the identification of issues that need to be considered in introducing biotope creation techniques at a rooftop space using eco-pond or eco-park creation techniques. Based on the result, a creation process and techniques were presented for the rooftop of Kyungdong Energy Company building located in Bundang, Sungnam city. The conclusions reached in this study are as follows. First, when structural problems such as load or leakage are resolved and when it is planned as a habitat within a range of carrying load, a rooftop may be habitats for various organisms. Second, same creation techniques for eco-ponds or eco-parks may be applied to create biotope in a rooftop. In fact, the introduction of a wetland ecosystem on a rooftop may contribute significantly in increasing biodiversity. In addition, it would be desirable to approach traditional rooftop revegetation methods in an ecological aspect and to introduce indigenous plants and to offer habitats to insects and birds. Third, in order to create rooftop biotope, there should be enough studies and experiments on resolving structural problems and on techniques or technologies to create habitats. Since the Kyongdong Energy Company rooftop biotope described in this study is the first experimental site in Korea, it requires a series of process to identify problems and to improve them by monitoring the site in the future. Through such studies and experiments, efficient rooftop biotope creation techniques should be developed and disseminated.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.723-731
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• 2001

As XML has become and emerging standard for information exchange on the World Wide Web it has gained attention in database communities of extract information from XML seen as a database model. Data in XML can be mapped to semistructured dta model based on edge-labeled graph and queries can be processed against it Here we propose new query optimization techniques using DTDs(Document Type Definitions) which have the schema information about XML data. Our techniques reduce traditional index techniques Also, as they preserve source database structure, they can process many kinds of complex queries. we implemented our techniques and provided preliminary performance results.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.151-164
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• 1986

The purpose of this study was to evaluate the marginal fit of metal ceramic crowns made by different techniques. The techniques were metal butt margin technique, platinum foil technique, shoulder powder techniques and wax technique. The latter three techniques were for the fabrication of collarless metal ceramic crowns. Ten crowns were made of each techniques, and marginal fit was evaluated using scanning electron microscope under X200 magnification. The results were as follows. 1. The marginal fit in the descending order were wax technique shoulder powder technique, platinum foil technique and metal butt margin, before cementation, and wax technique, shoulder powder technique, metal butt margin, and platinum foil technique, after cementation. 2. The fit of collarless metal ceramic crowns was comparable to metal ceramic crowns with metal butt margins. 3. There were no statistically significant differences between marginal fit of metal ceramic crowns made by different techniques.

• The Research Journal of the Costume Culture
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• v.30 no.1
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• pp.33-49
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• 2022

The purpose of this study is to analyze the expressive elements and techniques of graffiti appearing in the Moschino collection by Jeremy Scott. A theoretical examination of graffiti art and Moschino's creative designer Jeremy Scott was conducted using previous studies and publications. Accordingly, keywords about the expressive elements and techniques of graffiti and Moschino were identified, as follows: expressive elements of 'message (slogan)', 'symbolized letters or forms', 'logo and brand symbol', 'graffiti (scribbles)', 'child-like elements', 'daily element's and expressive techniques of 'using primary colors (color contrast)', 'deformation', 'distortion', 'exaggeration', 'illusion (trompe l'oeil)', 'collage (repetition)', 'simplification (flattening)', and 'borrowing heterogeneous objects'. These keywords were then used to analyze Moschino's collection, comprising seven years of Moschino's collection photographs officially recorded in the fashion magazine Vogue, ranging from the 2014 F/W to 2020 F/W collections. A total of 761 photos were initially collected, from which 561 were selected by the researcher. Expressive characteristics of graffiti in Moschino's collection were analyzed, and identified in the following categories: 'child-like playfulness', 'commercial satire', 'using daily elements', and 'borrowing non-representative techniques'. Accordingly, it was confirmed that expressive characteristics of graffiti were found in the Moschino collection by Jeremy Scott. This study anticipates the possibility of various interpretations from which fashion that communicates closely with contemporary art can be understood.