• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.845-852
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• 2011

The Spark Plasma Sintering(SPS) method offers a means of fabricating a sintered-body having high density without grain growth through short sintering time and a one-step process. A titanium compact having high density and purity was fabricated by the SPS process. It can be used to fabricate a Ti sputtering target with controlled parameters such as sintering temperature, heating rate, and pressure to establish the optimized processing conditions. The compact/target(?) has a diameter of ${\Phi}150{\times}6.35mm$. The density, purity, phase transformation, and microstructure of the Ti compact were analyzed by Archimedes, ICP, XRD and FE-SEM. A Ti thin-film fabricated on a $Si/SiO_2$ substrate by a sputtering device (SRN-100) was analyzed by XRD, TEM, and SIMS. Density and grain size were up to 99% and below $40{\mu}m$, respectively. The specific resistivity of the optimized Ti target was $8.63{\times}10^{-6}{\Omega}{\cdot}cm$.

• Korean Journal of Remote Sensing
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• v.22 no.4
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• pp.275-284
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• 2006

The noise sources of a Hyperion image are mainly due to the atmospheric effects, the sensor's instrumental errors, and A/D conversion. Though uncalibrated, overlapping, and all deep water absorption bands generally are removed, there still exist noisy bands. The visual inspection for selecting clean and stable processing bands is a simple practice, but is a manual, inefficient, and subjective process. In this paper, we propose that the extrema ratio be used for noise estimation and unsupervised band selection. The extrema ratio was compared with existing SNR and entropy measures. First, Gaussian, salt and pepper, and Speckle noises were added to ALI (Advanced Land Imager) images with relatively low noises, and the relation of noise level and those measures was explored. Second, the unsupervised band selection was performed through the EM (Expectation-Maximization) algorithm of the measures which were extracted from a Hyperion images. The Hyperion data were classified into 5 categories according to the image quality by visual inspection, and used as the reference data. The experimental result showed that the extrema ratio could be used effectively for band selection of Hyperion images.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.460-465
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• 2019

In this study, we aim to derive a solution from the structural analysis for electrical failure of single board computers for computing navigation information. By analyzing the characteristic factor, we identify that crack occur on the central processing unit board due to a certain structural problem, and that the physical effect by the crack make communication function be impossible to perform, which it causes booting error. In order to find the location of excessive stress causing the crack, structural analysis for the single board computer is done. From the structural analysis, the areas where stress concentration occurs are identified, and improvement methods changing the structures are developed. As a result, we shows that stresses are reduced entirely on the stress distribution for the improved structure. In addition, heat analysis shows that changing the structure to reduce stresses is not affect to the heat radiation, and the thermal resistance of the actual equipment is verified by measuring the temperature of the heat sink applied with the improved structure.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.467-467
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• 2017

토양수분 및 황사발생 연구에 있어 효율적인 광역 분석을 위하여 위성자료가 활용되고 있다. 활용 시나리오에 따라서는 준실시간 자료 수신, 처리가 필요하며 본 연구에서는 이에 대한 방안을 연구하기 위하여 유럽 EUMETSAT(European Organisation for the Exploitation of Meteorological Satellites)의 ASCAT(Advanced Scatterometer) Metop-A 자료에 대하여 파악하였다. 자료 수신 프로토콜에 있어서 FTP, HTTP 등 전통적 방법에 대한 현황과 함께 비교적 최근 기법인 OGC(Open Geospatial Consortium)　 WMS(Web Map Service), WCS(Web Coverage Service) 방식의 지원 현황에 대하여 확인하였다. 제공되는 자료 Format부분은 EPS Native와 BUFR(Binary Universal Form for the Representation of meteorological data)을 살펴보되 데이터 프로바이더 측에서 대부분 채택되고 있는 NetCDF(network Common Data Form)를 중심으로 파악하였다. 수신된 자료의 처리 자동화를 위한 소프트웨어는 OSGeo(The Open Source Geospatial Foundation)의 GDAL(Geospatial Data Abstraction Library), 미국 NCAR(National Center for Atmospheric Research)의 NCL(NCAR Command Language)을 중심으로 확인하였다. 자료 가공기법은 격자(Raster) 자료에 대한 기본 메타정보 확인, 좌표참조체계 변환, 해상도 및 Format 변환을 중심으로 확인하였다. 한편 OGC WMS, WCS는 자료의 전송 프로토콜 기법이면서 동시에 서버 사이드에서의 자료 변환 기능을 구비하고 있다. 예를 들어 Http Request에서 영역(Extent), Format 형식, 좌표참조체계를 지정할 수 있다. OGC WMS에 대한 EUMETSAT 파일럿 서비스에서 반환 자료의 공간적 영역, 복수 시점 제공 현황, 반환 포맷 지원 상황은 실제 메서드를 사용하여 파악하였고, 향후 발전 방향을 전망하였다.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.367-372
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• 2019

With the development of various IT technologies, data generated in the ship can be controlled through CAN communication, autonomous operation, and information provision in various situation. In addition, electronic navigation vessels with various functions have emerged, and navigation and communication equipment used in these vessels are mainly following the NMEA standard. Currently, NMEA-0183 is still mainly used, but more efficient multimedia transmission processing method is needed for multimedia transmission and USN equipment compatible using NMEA-2000 standard. Furthermore, Ethernet-based ship control is required. However, this paper proposes a multimedia transmission scheme to be smoothly linked with existing ship devices by utilizing CAN communication that can be easily used in the ship.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.276-286
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• 2008

The representative alignments for taking a stereo image by using a stereoscopic camera are the toed-in and the parallel alignment. In this paper, we tried to find important factors in the process that captures the stereo image by modifying parallel type 3D camera alignment to take the same object information as, for instance, when toed-in type was used. The modified parallel type 3D camera has merits in both types. As a result, three important factors are found by simulation to be inter-camera distance, field of view and convergence angle for both types. And the change of the convergence angle is known to be the most important factor at the stereo fusible area in processing. The effective ranges of these factors to simulate perfectly toed-in type by modified parallel type are strongly dependent on a user's circumstances such as mobile, official, theater and so on. Additionally, the error of the simulation is reduced when the focal length of the stereo camera is short and the convergence angle becomes smaller.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.33-40
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• 2021

Due to advanced complex strategies, the complexity of information that a commander must analyze is increasing. An intelligent service that can analyze battlefield is needed for the commander's timely judgment. This service consists of extracting knowledge from battlefield information, building a knowledge base, and analyzing the battlefield information from the knowledge base. This paper extract information similar to an input query by embedding the knowledge base built in the 2^nd step. The transformation model is needed to generate the embedded knowledge base and uses the random-walk algorithm. The transformed information is embedding using Word2Vec, and Similar information is extracted through cosine similarity. In this paper, 980 sentences are generated from the open knowledge base and embedded as a 100-dimensional vector and it was confirmed that similar entities were extracted through cosine similarity.

• Agribusiness and Information Management
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• v.10 no.2
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• pp.1-7
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• 2018

In the present day context of changing information needs of the farmers and diversified production systems there is an urgent need to look for the effective extension support system for the small and marginal farmers in the developing countries like India. The rapid developments in the collection and analysis of field data by using the spatial technologies like GPS&GIS were made available for the extension functionaries and clientele for the diversified information needs. This article describes the GIS and GPS based decision support system in precision agriculture for the resource poor farmers. Precision farming techniques are employed to increase yield, reduce production costs, and minimize negative impacts to the environment. The parameters those can affect the crop yields, anomalous factors and variations in management practices can be evaluated through this GPS and GIS based applications. The spatial visualisation capabilities of GIS technology interfaced with a relational database provide an effective method for analysing and displaying the impacts of Extension education and outreach projects for small and marginal farmers in precision agriculture. This approach mainly benefits from the emergence and convergence of several technologies, including the Global Positioning System (GPS), geographic information system (GIS), miniaturised computer components, automatic control, in-field and remote sensing, mobile computing, advanced information processing, and telecommunications. The PPP convergence of person (farmer), project (the operational field) and pixel (the digital images related to the field and the crop grown in the field) will better be addressed by this decision support model. So the convergence and emergence of such information will further pave the way for categorisation and grouping of the production systems for the better extension delivery. In a big country like India where the farmers and holdings are many in number and diversified categorically such grouping is inevitable and also economical. With this premise an attempt has been made to develop a precision farming model suitable for the developing countries like India.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.6
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• pp.223-234
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• 2019

Cyber attacks are an important factor that determines the victory and defeat of Network-centric wars in which advanced weapon systems are highly interlinked. In addition the increasing dependability on software as its develop as the latest fighter is demanding enhanced security measures for fighter software to Cyber attacks. In this paper, we apply the DO-326A, which is an airworthiness security certification standard, to design a risk-based security threat assessment process by reflecting characteristics and operational environment of fighter aircraft. To do this, we add the following steps in security threat assessment stage of DO-326A's airworthiness security certification process. First, we derive security threats of fighter. And then, we scored the security threat in terms of possibility and impact on the fighter. Finally, we determine the security risk severity.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.55-64
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• 2019

PURPOSE. The accuracy of denture bases was compared among injection molding, milling, and rapid prototyping (RP) fabricating method. MATERIALS AND METHODS. The maxillary edentulous master cast was fabricated and round shaped four notches were formed. The cast was duplicated to ten casts and scanned. In the injection molding method, designed denture bases were milled from a wax block and fabricated using SR Ivocap injection system. Denture bases were milled from a pre-polymerized block in the milling method. In the RP method, denture bases were printed and post-cured. The intaglio surface of the base was scanned and surface matching software was used to measure inaccuracy. Measurements were performed between four notches and two points in the mid-palatal suture to evaluate inaccuracy. The palatine rugae resolution was evaluated. One-way analysis of variance was used for statistical analysis at ${\alpha}=.05$. RESULTS. No statistically significant differences in distances among four notches (P>.05). The accuracy of the injection molding method was lower than those of the other methods in two points of the mid-palatal suture significantly (P<.05). The degree of palatine rugae resolution was significantly higher in the injection molding method than that in other methods (P<.05). CONCLUSION. The overall accuracy of the denture base is higher in milling and RP method than the injection molding method. The degree of fine reproducibility is higher in the injection molding method than the milling or RP method.