• 천문학회보
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• 제35권2호
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• pp.69.2-69.2
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• 2010

We investigate the southeastern region of the Vela supernova remnant (SNR) in the multi-wavelength domains. This region is quite interesting because it includes the bullet feature D/D´ and another SNR (the Vela Jr.). The C IV $\lambda\lambda1548$, 1551 emission-line morphologies obtained from the FIMS/SPEAR data show that there are several local peaks of C IV on the bullet D/D´ and the Vela Jr. SNR. This may provide clues to direct interaction between both SNRs. Also, we found that the southeastern side of the Vela is in direct contact with an H-alpha ring feature whose central source seems to be a B-type star, HD 76161. The C IV emission peaks along this contact boundary. We investigate this interacting region in detail.

• Journal of Astronomy and Space Sciences
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• 제33권2호
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• pp.75-92
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• 2016

It is generally believed that the high energy emissions from isolated pulsars are emitted from relativistic electrons/positrons accelerated in outer magnetospheric accelerators (outergaps) via a curvature radiation mechanism, which has a simple exponential cut-off spectrum. However, many gamma-ray pulsars detected by the Fermi LAT (Large Area Telescope) cannot be fitted by simple exponential cut-off spectrum, and instead a sub-exponential is more appropriate. It is proposed that the realistic outergaps are non-stationary, and that the observed spectrum is a superposition of different stationary states that are controlled by the currents injected from the inner and outer boundaries. The Vela and Geminga pulsars have the largest fluxes among all targets observed, which allows us to carry out very detailed phase-resolved spectral analysis. We have divided the Vela and Geminga pulsars into 19 (the off pulse of Vela was not included) and 33 phase bins, respectively. We find that most phase resolved spectra still cannot be fitted by a simple exponential spectrum: in fact, a sub-exponential spectrum is necessary. We conclude that non-stationary states exist even down to the very fine phase bins.

• 천문학회보
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• 제37권2호
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• pp.99.2-99.2
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• 2012

We updated the far-ultraviolet (FUV) spectral images of the entire Vela supernova remnant (SNR) using newly processed FIMS/SPEAR data. In the present study, we compare the newly produced FUV images with the X-ray and $H{\alpha}$ images, and examine how the Vela SNR evolves and interacts with the ambient medium on a global scale. The comparison with X-ray images has revealed a FUV filamentary feature corresponding with the boundary of the northeast-southwest asymmetry of the X-ray shell. The relatively low O IV] ${\lambda}1404$ to O III] ${\lambda}{\lambda}1661$, 1666 ratio estimated on the FUV filament is compatible with the previous proposal that the observed asymmetry of the Vela SNR could be due to the ${\gamma}2$ Velorum stellar wind bubble (SWB). The southwest FUV features surrounding a faint extended X-ray region are characterized as the region where the Vela SNR is interacting slightly stronger with ambient mediums within the dim X-ray southwest section. From a comparison with the $H{\alpha}$ image, we identify a ring-like $H{\alpha}$ feature overlapped with an extended hot X-ray feature of similar size and two local peaks of C IV ${\lambda}{\lambda}1548$, 1551 emission. Their morphologies are consistent with the expected shape when the $H{\alpha}$ ring is in direct contact with the near or far side of the Vela SNR. We suggest that the B3V-type star HD 76161 found at the center of the $H{\alpha}$ ring would be the exciting source of the H II region.

• 천문학회보
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• 제36권2호
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• pp.110.2-110.2
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• 2011

Nishikida et al. (2006) presented the first far-ultraviolet (FUV) em${\lambda}$ission-line images of the Vela supernova remnant (SNR) obtained with FIMS/SPEAR instrument. Those include C III ${\lambda}$977, O VI ${\lambda}{\lambda}$1032, 1038, Si IV+O IV] ${\lambda}{\lambda}$1393, 1403 (un-resolved), C IV ${\lambda}{\lambda}$1548, 1551 emission-line images. As a following work, we re-constructed these emission-line images using the new-version processed FIMS/SPEAR data. Additionally, we made N IV] ${\lambda}$1486, He II ${\lambda}$1640.5, O III] ${\lambda}{\lambda}$1661, 1666 emission-line images. The new-version images cover the whole region of the Vela SNR and show more resolved features than the old-version. We compare these FUV emission-line images with other wavelength (X-ray, optical, etc.) images obtained in previous studies.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1994년도 한국우주과학회보 제3권2호
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• pp.23-23
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• 1994

No Abstract. See Full-text

• 자원환경지질
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• 제56권4호
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• pp.365-384
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• 2023

서태평양에 위치한 총 173개의 지진 관측소에서 획득한 2,026개의 지진 자료에 분할 파형 역산을 적용하여 서태평양 지역 맨틀 전이대 깊이까지 S파 등방성 속도 및 방사 이방성에 대한 연구를 수행했다. 그 결과 필리핀해판의 경우 페러스-벨라 분지(Parece-Vela basin)에서 고속도 이상이 30 km 깊이까지 나타나는 것에 비해 서필리핀 분지(West Philippine basin)에서 고속도 이상이 50 km 깊이까지 유지되었다. 페러스-벨라 분지 하부 약 80 km 깊이부터 나타나는 저속도 이상이 깊이가 깊어짐에 따라 서필리핀 분지로 확장되는 경향을 보였는데 이는 페러스-벨라 분지와 서필리핀 분지 사이의 연령차이에 의한 것으로 보인다. 또한 캐롤라인 해저 산열(Caroline seamount chain) 및 캐롤라인 판의 하부에서 강한 저속도 이상이 약 200 km 깊이까지 보인다. 방사 이방성 모델의 경우 서태평양에서 전반적으로 양의 이방성에 우세하게 나타났으며 페러스-벨라 분지에서 약 50 km 깊이까지, 마리아나 해구를 따라 섭입하는 태평양판의 약 220 km 깊이부터 음의 이방성이 관측되었다. 캐롤라인 해저산열 하부 약 200 km 깊이까지 강한 양의 이방성이 나타났는데 이는 해저산열을 형성한 플룸과 이동하는 태평양판 사이에 발생한 끌림(drag)에 의한 것으로 보인다. 온통-자바 해대(Ontong-Java plateau) 지역 하부에서는 40 ~ 180 km 깊이에서 고속도 이상이 발견되었으며, 이는 탈수된 플룸 물질의 부착으로 인한 비정상적으로 두꺼운 암석권의 존재를 나타낸다.

• 산경연구논집
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• 제13권11호
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• pp.1-10
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• 2022

Purpose: This study measures the influence of facilitating conditions on employees' attitudes towards the adoption of big data analytics by selected medical aid organizations in Durban. In the health care sector, there are various sources of big data such as patients' medical records, medical examination results, and pharmacy prescriptions. Several organizations take the benefits of big data to improve their performance and productivity. Research design, data, and methodology: A survey research strategy was conducted on some selected medical aid organizations. A non-probability sampling and the purposive sampling technique were adopted in this study. The collected data was analysed using version 23 of Statistical Package for Social Science (SPSS) Results: the results show that the "facilitating conditions" have a positive influence on employees' attitudes in the adoption of big data analytics Conclusions: The findings of this study provide empirical and scientific contributions of the facilitating conditions issues regarding employee attitudes toward big data analytics adoption. The findings of this study will add to the body of knowledge in this field and raise awareness, which will spur further research, particularly in developing countries.

• Toxicological Research
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• 제22권4호
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• pp.329-332
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• 2006

Ethanolic extract of Aloe vera (Aloe barbadensis Miller) was examined for the cellular toxicity on HepG2 human hepatocellular carcinoma cells. Treatment with Aloe vera extract resulted in DNA fragmentation but not LDH release, suggesting an apoptosis instead of necrosis. Aloe vera induced cytotoxicity was mediated by decrease in ATP levels, whereas GSH depletion, increase in intracellular $Ca^{2+}$, or activation of caspase-3/7 could not be observed with statistical significance. No activation of caspase-3/7 suggests the possibility of caspase-independent apoptosis. Taken together, our results show that Aloe vera extract induce HepG2 apoptosis by ATP depletion-related impairment of mitochondria, which is caspase-independent.

• International Journal of Computer Science & Network Security
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• 제24권7호
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• pp.186-194
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• 2024

This study aims to investigate the technological-organizational-environmental (TOE) factor of influencing small and medium-sized enterprises (SMEs') social media (SM) adoption in developing countries. This study used a closed-ended questionnaire to collect data from randomly selected respondents (owners, executives, and managers) from SMEs operating in Pakistan. SMART PLS version 3.2.8 was used for path analysis of 423 responses. The research findings include the direct influence of TOE factors on SMEs SM adoption and SMEs performance. Furthers, this paper also has implications for practitioners and scholars interested in exploring the SM adoption and usage in SMEs.

• 한국통신학회논문지
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• 제29권1C호
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• pp.102-110
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• 2004

본 논문에서는 이차원 이산 웨이블릿 변환을 이용한 실시간 영상 압축 및 복원 프로세서의 구조를 제안하고 ASIC(Application specific integrated circuit) 라이브러리를 이용하여 최소의 하드웨어로 구현하였다. 구현된 하드웨어에서 데이터 패스부는 웨이블릿 변환과 역변환을 수행하는 DWT 커널(Kernel)부, 양자화기 및 역양자화기, 허프만 엔코더 및 디코더, 웨이블릿 역변환 시 계수의 덧셈을 수행하는 덧셈기 및 버퍼, 그리고 입출력을 위한 인터페이스와 버퍼로 구성하였다. 제어부는 프로그래밍 레지스터와 명령어를 디코딩하여 제어 신호를 생성하는 주 제어부, 그리고 상태를 외부로 알리는 상태 레지스터로 구성된다. 프로그래밍 조건에 따라서 영상을 압축할 때의 출력은 웨이블릿 계수, 양자화 계수 혹은 양자화 인덱스, 그리고 허프만 코드 중에서 선택하여 발생할 수 있고 영상을 복원할 때의 출력은 허프만 디코딩 결과, 복원된 양자화 계수 그리고 복원된 웨이블릿 계수 중에서 선택하여 발생할 수 있다. 프로그래밍 레지스터는 총 16개로 구성되어 있는데 각각이 한번의 수직 혹은 수평 방향의 웨이블릿 변환을 수행할 수 있고 각각의 레지스터들이 차례대로 동작하기 때문에 4 레벨의 웨이브릿 변환을 한번의 프로그래밍으로 수행가능하다. 구현된 하드웨어는 Hynix 0.35m CMOS 공정의 합성 라이브러리를 가지고 Synopsys 합성툴을 이용하여 게이트 레벨의 네트리스트(Netlist)를 추출하였고 이 네트리스트로부터 Vela 툴을 이용하여 타이밍정보를 추출하였다. 추출된 네트리스트와 타이밍정보(sdf 파일)를 입력으로 하여 NC-Verilog를 이용하여 타이밍 시뮬레이션을 수행하여 구현된 회로를 검증하였다. 또한 Apollo 툴을 이용하여 PNR(Place and route) 및 레이아웃을 수행하였다. 구현된 회로는 약 5만 게이트의 적은 하드웨어 자원을 가지고 최대 80MHz에서 동작 가능하였다.