• 제목/요약/키워드: science and technology researcher

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MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT-DEFORMED AlMg4 ALLOYS WITH THE VARIATIONS OF Mn, Fe, AND Si CONTENTS

  • DA B. LEE;BONG H. KIM;KWEON H. CHOI;SEUNG Y. YANG;NAM S. KIM;SEONG H. HA;YOUNG O. YOON;HYUN K. LIM;SHAE KIM;SOONG K. HYUN
    • Archives of Metallurgy and Materials
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    • 제65권4호
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    • pp.1255-1259
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    • 2020
  • This paper aims to investigate the microstructural evolution and mechanical properties of hot-deformed AlMg4 alloys with Mn, Fe, and Si as the main impurities. For this purpose, solidification behavior and microstructural evolution during hot-rolling and heat-treatment processes are investigated by using theoretical calculations and experimental characterization. The crystallization and morphological transformation of intermetallic Al3Fe, Al6Mn, and Mg2Si phases are revealed and discussed in terms of the variation in chemical composition. Following a homogenization heat-treatment, the effect of heat treatment on the intermetallic compounds is also investigated after hot-rolling. It was revealed that the Mg2Si phase can be broken into small particles and spherodized more easily than the Al3Fe intermetallic phase during the hot-rolling process. For the Mn containing alloys, both yield and ultimate tensile strength of the hot-rolled alloys increased from 270 to 296 MPa while elongation decreased from 17 to 13%, which can be attributed to Mn-containing intermetallic as well as dispersoid.

Fusion of DEMs Generated from Optical and SAR Sensor

  • Jin, Kveong-Hyeok;Yeu, Yeon;Hong, Jae-Min;Yoon, Chang-Rak;Yeu, Bock-Mo
    • 대한공간정보학회지
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    • 제10권5호
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    • pp.53-65
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    • 2002
  • The most widespread techniques for DEM generation are stereoscopy for optical sensor images and SAR interferometry(InSAR) for SAR images. These techniques suffer from certain sensor and processing limitations, which can be overcome by the synergetic use of both sensors and DEMs respectively. This study is associated with improvements of accuracy with consistency of image's characteristics between two different DEMs coming from stereoscopy for the optical images and interferometry for SAR images. The MWD(Multiresolution Wavelet Decomposition) and HPF(High-Pass Filtering), which take advantage of the complementary properties of SAR and stereo optical DEMs, will be applied for the fusion process. DEM fusion is tested with two sets of SPOT and ERS-l/-2 satellite imagery and for the analysis of results, DEM generated from digital topographic map(1 to 5000) is used. As a result of an integration of DEMs, it can more clearly portray topographic slopes and tilts when applying the strengths of DEM of SAR image to DEM of an optical satellite image and in the case of HPF, the resulting DEM.

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플러그인 하이브리드자동차용 리튬이온 이차전지 (Lithium-Ion Batteries for Plug-In Hybrid Electric Vehicle)

  • 조만;손영목;나도백;길상철;김상우
    • 에너지공학
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    • 제19권2호
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    • pp.81-91
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    • 2010
  • 플러그인 하이브리드자동차의 개발이 활발하다. 배전망으로부터의 전력을 수송에 사용함으로써 온실효과가스 배출과 화석연료소비를 저감시킨다. 향후 2030년까지의 플러그인 하이브리드자동차용 축전장치로는 리튬이온 이차전지가 가장 현실적인 기술이다. 리튬이온 이차전지 기술의 현황을 리뷰하고 장차 실용화될 것으로 전망되는 양극소재의 특성을 비교한다.

Self-Study Journey from a Novice to an Expert for Computational Thinking Practices

  • Green, James;Park, Young-Shin
    • 한국지구과학회지
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    • 제42권5호
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    • pp.588-603
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    • 2021
  • This study details a researcher's self-study journey in advancing from a computational thinking (CT) novice to an expert. The researcher went through a four-stage process, with a preliminary literature review preceding the four stages. From the literature review, the computational thinking analysis (CT_AT) tool was developed for use in stage one to analyze science, technology, engineering, art, and mathematic (STEAM) modules. Although no discernable patterns were found in analyzing the five science and five engineering-based modules, the analysis revealed which CT practices were missing or weakly exposed. In stage two activities were suggested to promote these missing or weakly exposed practices. Stage three required the researcher to develop his own STEAM module from the viewpoint of exposing students to CT. The fourth stage was to validate the CT_AT through interviews with pre-service and in-service teachers. These interviews led to changes in the CT_AT tool and, as a result, the researcher produced a guidebook that could be used by teachers in their own CT studies. This guidebook can be used by teachers to develop and become competent in CT skills.

과학기술 전거데이터 시스템에서의 해외 학술논문 저자 식별요소 추출 (Extraction of Author Identification Elements of Overseas Academic Papers on Authority Data System for Science and Technology)

  • 최현미;이석형;김광영;김환민
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2013년도 춘계학술대회
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    • pp.711-713
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    • 2013
  • 페이스북, 트위터, 등의 소셜 네트워크의 확산으로 전 세계의 다양한 인적정보를 접할 수 있다. 과학기술 분야에서도 많은 인적정보가 있지만 과학기술자 정보가 체계적으로 정리되지 않아 협력 연구 파트너, 등 업무에 적합한 연구자를 찾기 어려운 문제점이 있다. 이런 문제점을 해결하고자 학술문헌 저자를 중심으로 과학기술 전거데이터를 구축하고 있다. 이 논문에서는 1994년부터 2012년까지 수집한 해외 학술논문 저자명 전거데이터를 구축하기 위하여 수백만건의 학술논문에서 저자 식별 요소를 추출한다. 저자 식별요소는 한글, 영문, 한문(일본어 포함)을 대상으로 저자명, 소속기관명, 학술지명, 발행년도, 키워드, 공저자와 공저자 소속기관, 등이 있다. 이 언어별 식별정보를 기반으로 해외 학술논문 정보에서 저자 식별 정보를 추출하여 데이터베이스를 구축하였다. 향후, 이 추출된 정보를 기반으로 저자 식별 정보를 클러스터링하고 수정, 편집하여 연구자에 대한 학술정보 활동내역을 정리할 예정이다. 구축될 해외 학술논문 전거 데이터는 연구 협력 파트너 찾기, 과제 심사위원 추천, 등 연구자 정보의 활용도를 높여 연구자 커뮤니티를 활성화시키는데 유용하게 사용될 수 있다.

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Digital Transformation Requirements at Saudi Universities from Faculty Members' Perspectives

  • Taha Mansor Khawaji
    • International Journal of Computer Science & Network Security
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    • 제23권11호
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    • pp.8-20
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    • 2023
  • The current study aims to determine digital transformation (organizational, technical, and human resources) requirements at Saudi universities from Umm Al-Qura University faculty members' perspectives. The researcher used a quantitative approach based on the descriptive analytical design. To answer the questions of the study, the researcher used the questionnaire as a data collection tool. The questionnaire was sent electronically to faculty members working in colleges and institutes affiliated with Umm Al-Qura University in Makkah Al-Mukarramah, Saudi Arabia. The questionnaire consisted of the three dimensions of digital transformation: organizational; technical; and human resources requirements. The results showed that requirements related to human resources came first with an average of 2.25 then the organizational requirements with an average of 1.95, and in the last, technical requirements came with an average of 1.64. In addition, some suggestions were given by the participants (faculty members) related to the mechanism that could contribute to implementing digital transformation at Saudi universities. Likewise, at the end of the study, the researcher has given some suggestions related to the implementation of digital transformation requirements at Saudi universities.

Changes in the Structure of Collaboration Network in Artificial Intelligence by National R&D Stage

  • Hyun, Mi Hwan;Lee, Hye Jin;Lim, Seok Jong;Lee, KangSan DaJeong
    • Journal of Information Science Theory and Practice
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    • 제10권spc호
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    • pp.12-24
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    • 2022
  • This study attempted to investigate changes in collaboration structure for each stage of national Research and Development (R&D) in the artificial intelligence (AI) field through analysis of a co-author network for papers written under national R&D projects. For this, author information was extracted from national R&D outcomes in AI from 2014 to 2019. For such R&D outcomes, NTIS (National Science & Technology Information Service) information from the KISTI (Korea Institute of Science and Technology Information) was utilized. In research collaboration in AI, power function structure, in which research efforts are led by some influential researchers, is found. In other words, less than 30 percent is linked to the largest cluster, and a segmented network pattern in which small groups are primarily developed is observed. This means a large research group with high connectivity and a small group are connected with each other, and a sporadic link is found. However, the largest cluster grew larger and denser over time, which means that as research became more intensified, new researchers joined a mainstream network, expanding a scope of collaboration. Such research intensification has expanded the scale of a collaborative researcher group and increased the number of large studies. Instead of maintaining conventional collaborative relationships, in addition, the number of new researchers has risen, forming new relationships over time.

Services Quality Improvement through Control Management Cloud-Based SLA

  • Abel Adane
    • International Journal of Computer Science & Network Security
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    • 제23권5호
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    • pp.89-94
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    • 2023
  • Cloud-based technology is used in different organizations around the world for various purposes. Using this technology, the service providers provide the service mainly SaaS, PaaS and while the cloud service consumer consumes the services by paying for the service they used or accessed by the principle of "pay per use". The customer of the services can get any services being at different places or locations using different machines or electronic devices. Under the conditions of being well organized and having all necessary infrastructures, the services can be accessed suitably. The identified problem in this study is that cloud providers control and monitor the system or tools by ignoring the calculation and consideration of various faults made from the cloud provider side during service delivery. There are currently problems with ignoring the consumer or client during the monitoring and mentoring system for cloud services consumed at the customer or client level by SLA provisions. The new framework was developed to address the above-mentioned problems. The framework was developed as a unified modeling language. Eight basic components are used to develop the framework. For this research, the researcher developed a prototype by using a selected cloud tool to simulate and java programming language to write a code as well as MySQL to store data during SLA. The researcher used different criteria to validate the developed framework i.e. to validate SLA that is concerned with a cloud service provider, validate what happened when the request from the client-side is less than what is specified in SLA and above what is specified in SLA as well as implementing the monitoring mechanism using the developed Monitoring component. The researcher observed that with the 1st and 3rd criteria the service level agreement was violated and this indicated that if the Service level agreement is monitored or managed only by cloud service prover, there is a violation of LSA. Therefore, the researcher recommended that the service level agreement be managed by both cloud service providers and service consumers in the cloud computing environment.