• 천문학회보
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• 제35권2호
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• pp.28.2-28.2
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• 2010

We investigate star clusters in the Stephan's Quintet using Wide Field Camera 3 of the Hubble Space Telescope and three filters (F438W, F606W, F814W). Stephan's Quintet located at ~ 85 Mpc, so most star clusters are seen like point source even in HST image. We perform the Point Spread Funtion fitting photometry to find star clusters. Then we have selected 749 star cluster candidates by visual inspection. Usinng simple steallr population models (Bruzual & Charlot, 2003), we estimate ages of these star clusters. Many young star clusters found in tidal features of NGC 7318 and NGC 7319. Also star clusters in the shocked region of NGC7318 have younger age than those in NGC 7319 tidal tail. These result implies interaction which distrupt NGC 7319 first, and collision between NGC 7318 A/B occurred. In contrast, old star clusters are mainly located in NGC 7317 and in the center of other galaxies. Implications of these result will be discussed.

• 스마트미디어저널
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• 제7권2호
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• pp.9-14
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• 2018

The k-ary n-cube $Q^k_n$ is widely used in the design and implementation of parallel and distributed processing architectures. It consists of $k^n$ identical nodes, each node having degree 2n is connected through bidirectional, point-to-point communication channels to different neighbors. On $Q^k_n$ we would like to transmit packets from a source node to 2n destination nodes simultaneously along paths on this network, the $i^{th}$ packet will be transmitted along the $i^{th}$ path, where $0{\leq}i{\leq}2n-1$. In order for all packets to arrive at a destination node quickly and securely, we present an $O(n^3)$ routing algorithm on $Q^k_n$ for generating a set of one-to-many node-disjoint and nearly shortest paths, where each path is either shortest or nearly shortest and the total length of these paths is nearly minimum since the path is mainly determined by employing the Hungarian method.

• 천문학회지
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• 제55권5호
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• pp.173-194
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• 2022

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

• 한국소음진동공학회논문집
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• 제22권8호
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• pp.777-783
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• 2012

진동 인텐시티는 진동시스템에서 진동원의 위치를 찾는데 사용되어 왔다. 벡터 표현법 사용에 의해 파워흐름의 원인과 진동에너지 전달경로가 밝혀질 수 있다. 그러나, 판과 같은 구조물의 넓은 면적으로 인해 벡터 가시화를 사용하여 명확한 전달경로를 알아낼 수 없었다. 실험적으로 큰 면적의 물체에서는 측정점의 수가 늘어나게 된다. 이것은 측정에 많은 시간이 요구된다. 이번 연구에서는 FEM과 실험에 의한 모든 면에서 파워흐름 전달경로를 분명하게 가리키기 위해 유선 표현법이 사용되었다. 진동 인텐시티 전달경로를 분명하게 향상시키기 위해 실험과 FEM으로부터의 유선 표현을 비교하였다. 또한 FEM과 실험의 개선된 전달경로 가시화를 기존의 벡터표현과 비교하였다. 이 유선 가시화는 큰 표면을 갖는 판과 같은 구조물에 대해 진동원과 상세한 에너지 전달경로를 확인하는데 유용하다. 그 뿐만 아니라, 이 가시화 방법은 실험과 FEM 해석에 대해 많은 측정점을 필요로 하지 않는다.

• 천문학회보
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• 제44권2호
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• pp.48.1-48.1
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• 2019

We found a diffuse Hα feature with a large size of ~2' around a Herbig star, MWC 1080. It shows a strong correlation with the elongated outflow cavity centered on the star. To investigate the diffuse Hα source and the molecular cavity in detail, we carried out the high-resolution NIR spectroscopy using IGRINS. We detected six hydrogen Brackett line series, seven H2 lines, and an [Fe II] forbidden line. With the obtained spatial, kinematic, and line ratio results, we discuss the characteristics of the central MWC 1080A, the NE outflow cavity, and the SE molecular cloud regions separately. Most of the bright Brγ sources around MWC 1080A were found to be reflection nebulae, but a point-like Brγ source close to another young star, MWC 1080E, was identified as a distinct source due to MWC 1080E itself. The narrow components of the H2 lines observed around MWC 1080A were found to trace PDRs located on the wall of the main outflow cavity. Based on the shock-excited H2 and [Fe II] lines detected just inside a bow-shock shape Hα feature, we suggest that it represents the actual shock at the head of the NE outflow from MWC 1080A. Also, we newly detected the shock-excited H2 and [Fe II] lines with highly blueshifted velocities in the SE molecular cloud region. They could be related to unrevealed outflows from other young stars existing around MWC 1080A.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.181-184
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• 2001

Chemical Mechanical Polishing(CMP) of Shallow Trench Isolation(STD structure in 0.18 m semiconductor device fabrication is studied. CMP process is applied for the STI structure with and without reverse moat pattern and End Point Detection (EPD) method is tested. To optimize the transistor properties related metal 1 parameters. we studied the correlation between CMP thickness of STI using high selectivity slurry. DOE of gate etch recipe, and 1st metal DC values. Remaining thickness of STI CMP is proportional to the thickness of gate-etch process and this can affect to gate profile. As CMP thickness increased. the N-poly foot is deteriorated. and the P-Poly Noth is getting better. If CD (Critical Dimension) value is fixed at some point,, all IDSN/P values are in inverse proportional to CMP thickness by reason of so called Profile Effect. Weve found out this phenomenon in all around DOE conditions of Gate etch process and we also could understand that it would not have any correlation effects between VT and CMP thickness in the range of POE 120 sec conditions. As CMP thickness increased by $100\AA$. 3.2 $u\AA$ of IDSN is getting better in base 1 condition. In POE 50% condition. 1.7 $u\AA$ is improved. and 0.7 $u\AA$ is improved in step 2 condition. Wed like to set the control target of CD (critical dimension) in gate etch process which can affect Idsat, VT property versus STI topology decided by CMP thickness. We also would like to decide optimized thickness target of STI CMP throughout property comparison between conventional STI CMP with reverse moat process and newly introduced STI CMP using high selectivity slurry. And we studied the process conditions to reduce Gate Profile Skew of which source known as STI topology by evaluation of gate etch recipe versus STI CMP thickness.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.181-184
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• 2001

Chemical Mechanical Polishing(CMP) of Shallow Trench Isolation(STI) structure in 0.18 m semiconductor device fabrication is studied. CMP process is applied for the STI structure with and without reverse moat pattern and End Point Detection (EPD) method is tested. To optimize the transistor properties related metal 1 parameters, we studied the correlation between CMP thickness of STI using high selectivity slurry, DOE of gate etch recipe, and 1st metal DC values. Remaining thickness of STI CMP is proportional to the thickness of gate-etch process and this can affect to gate profile. As CMP thickness increased, the N-poly foot is deteriorated, and the P-Poly Noth is getting better. If CD (Critical Dimension) value is fixed at some point, all IDSN/P values are in inverse proportional to CMP thickness by reason of so called Profile Effect. Weve found out this phenomenon in all around DOE conditions of Gate etch process and we also could understand that it would not have any correlation effects between VT and CMP thickness in the range of POE 120 sec conditions. As CMP thickness increased by 100 ${\AA}$, 3.2 u${\AA}$ of IDSN is getting better in base 1 condition. In POE 50% condition, 1.7 u${\AA}$ is improved, and 0.7 u${\AA}$ is improved in step 2 condition. Wed like to set the control target of CD (critical dimension) in gate etch process which can affect Idsat, VT property versus STI topology decided by CMP thickness. We also would like to decide optimized thickness target of STI CMP throughout property comparison between conventional STI CMP with reverse moat process and newly introduced STI CMP using high selectivity slurry. And we studied the process conditions to reduce Gate Profile Skew of which source known as STI topology by evaluation of gate etch recipe versus STI CMP thickness.

• 분석과학
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• 제32권5호
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• pp.210-216
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• 2019

Concentrations of Cu, Zn, Fe, Mn, Ni and Cr have been estimated in sediments of the Shitalakhya River at Polash-Ghorashal area, Narsingdi, Bangladesh. 36 samples of sediments from nine sampling point at different locations of Shitalakhya River were collected to determine the concentration of Cu, Zn, Fe, Mn, Ni, Cr and the samples were analyzed by atomic absorption spectrophotometer (AAS). The obtained results were compared with national and international guidelines. The levels of heavy metal concentrations in sediments were found to decrease in the order of Fe > Mn > Zn > Ni > Cu > Cr, respectively. The heavy metal concentration in sediment of Shitalakhya was below the recommended safe limits of heavy metals by WHO, FAO and other international standards. Contamination factor (CF) of Zn and Cu at sampling point Fsd2 show higher (> 1) values due to the influence of external discrete sources like wastage catalysts of ZnO and CuO. Geo-accumulation index values of the study indicate as non-contaminated to moderately contaminate.

• 한국지능시스템학회논문지
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• 제17권2호
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• pp.208-213
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• 2007

최근 가정용 로봇 연구가 활발히 진행됨에 따라, 가정과 같은 다이내믹한 환경에서 로봇이 목소리를 포함한 음원에 반응하고 그 위치를 정확히 찾아가는 것이 매우 중요해지고 있다. 인간이 목표물에 도달하기 위해 경로를 선택할 때, 그 목표물이 소리인 경우는 현재 위치에서 음원의 방향을 추적한다. 또한 그 목표물의 위치가 지도로 주워질 경우에는 현재 위치와 목표물의 절대적 방위를 기준으로 추적한다. 본 논문에서는 이처럼 사람이 다른 사람의 목소리를 듣고 반응하거나 어떤 방향으로 가고자할 때 소리가 나는 방향이나 지도를 통해 대략 자신만의 방위를 만드는 것에 착안하여, 지능형 모바일 로봇에 음원추적 장치와 전자나침반을 장착함으로써 음원의 방향 또는 절대 방위를 기준으로 목표물을 찾아가는 알고리즘을 제시하고자 한다.

• 기술혁신연구
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• 제21권1호
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• pp.109-139
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• 2013

본 연구는 미국과 한국의 오픈 소스 소프트웨어(OSS) 기업의 사례를 중심으로 기존 기술추격이론이 지식 집약적인 OSS 산업에서도 적용되는 지를 분석하고 후발기업들이 기술추격의 발판을 마련할 시사점을 연구하는 것을 그 목적으로 한다. 이를 위하여, 국내 SW 기업들의 인터뷰와 미국 SW 기업들의 기록문서 분석 및 2차 출처들의 검토를 통한 실증적 연구를 수행하였으며, 패러다임의 변곡점 판별과 기술체제의 비교라는 분석의 틀을 이용하여 소프트웨어(SW) 기업의 기술추격 과정을 연구하였다. 본 연구결과, OSS 기업의 기술추격을 설명하는데 있어 기존 기술추격이론의 이론적 논거가 유효하지 않다고 판별하였고 기술체제의 비교 결과, 후발기업의 기술추격을 효과적으로 촉진하는 유효한 요소들을 파악하였다. 또한 저자들은 OSS 기업의 사례연구 결과를 통하여 탈 추격이론이 주장하는 기존 이론의 제약을 진단하고 OSS 의 낮은 전유성이 역설적으로 기술추격을 촉진하는 새로운 기술 체제에 대한 해석을 논의한다.