• 마이크로전자및패키징학회지
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• 제17권4호
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• pp.73-76
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• 2010

A two-facet approach was used to investigate the parametric performance of functional high-speed DDR3 (Double Data Rate) DRAM (Dynamic Random Access Memory) die placed in different types of BGA (Ball Grid Array) packages: wire-bonded BGA (FBGA, Fine Ball Grid Array), flip-chip (FCBGA) and lead-bonded $microBGA^{(R)}$. In the first section, packaged live DDR3 die were tested using automatic test equipment using high-resolution shmoo plots. It was found that the best timing and voltage margin was obtained using the lead-bonded microBGA, followed by the wire-bonded FBGA with the FCBGA exhibiting the worst performance of the three types tested. In particular the flip-chip packaged devices exhibited reduced operating voltage margin. In the second part of this work a test system was designed and constructed to mimic the electrical environment of the data bus in a PC's CPU-Memory subsystem that used a single DIMM (Dual In Line Memory Module) socket in point-to-point and point-to-two-point configurations. The emulation system was used to examine signal integrity for system-level operation at speeds in excess of 6 Gb/pin/sec in order to assess the frequency extensibility of the signal-carrying path of the microBGA considered for future high-speed DRAM packaging. The analyzed signal path was driven from either end of the data bus by a GaAs laser driver capable of operation beyond 10 GHz. Eye diagrams were measured using a high speed sampling oscilloscope with a pulse generator providing a pseudo-random bit sequence stimulus for the laser drivers. The memory controller was emulated using a circuit implemented on a BGA interposer employing the laser driver while the active DRAM was modeled using the same type of laser driver mounted to the DIMM module. A custom silicon loading die was designed and fabricated and placed into the microBGA packages that were attached to an instrumented DIMM module. It was found that 6.6 Gb/sec/pin operation appears feasible in both point to point and point to two point configurations when the input capacitance is limited to 2pF.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.7-8
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• 2003

Since it was first reported in 1997, somatic cell cloning has been demonstrated in several other mammalian species. On the mouse, it can be cloned from embryonic stem (ES) cells, fetus-derived cells, and adult-derived cells, both male and female. While cloning efficiencies range from 0 to 20%, rates of just 1-2% are typical (i.e. one or two live offspring per one hundred initial embryos). Recently, abnormalities in mice cloned from somatic cells have been reported, such as abnormal gene expression in embryo (Boiani et al., 2001, Bortvin et al., 2003), abnormal placenta (Wakayama and Yanagimachi 1999), obesity (Tamashiro et ai, 2000, 2002) or early death (Ogonuki et al., 2002). Such abnormalities notwithstanding, success in generating cloned offspring has opened new avenues of investigation and provides a valuable tool that basic research scientists have employed to study complex processes such as genomic reprogramming, imprinting and embryonic development. On the other hand, mouse ES cell lines can also be generated from adult somatic cells via nuclear transfer. These 'ntES cells' are capable of differentiation into an extensive variety of cell types in vitro, as well assperm and oocytes in vivo. Interestingly, the establish rate of ntES cell line from cloned blastocyst is much higher than the success rate of cloned mouse. It is also possible to make cloned mice from ntES cell nuclei as donor, but this serial nuclear transfer method could not improved the cloning efficiency. Might be ntES cell has both character between ES cell and somatic cell. A number of potential agricultural and clinical applications are also are being explored, including the reproductive cloning of farm animals and therapeutic cloning for human cell, tissue, and organ replacement. This talk seeks to describe both the relationship between nucleus donor cell type and cloning success rate, and methods for establishing ntES cell lines. (중략)

• 동의생리병리학회지
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• 제18권4호
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• pp.1173-1178
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• 2004

Gagamhwanglyeonhaedog-tang(GHH), a Korean genuine medicine, is a newly designed herbal drug formula based on the traditional oriental pharmacological knowledge for the purpose of treating tumorous diseases. Apoptosis is an evolutionarily conserved suicide program residing in cells. It leads to cell death through a tightly regulated process resulting in the removal of damaged or unwanted tissue. In the present study, the apoptosis inducing activities of the decocted water extract of GHH were studied. Results of the 3- [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay showed that GHH had a strong cytotoxic effect on HL-60 cells. The number of live cells was less than 20% after exposure to 1㎎/㎖ GHH for 48 hr. GHH increased cytotoxicity of HL-60 cells in a dose- and time­dependent manner. Cell apoptosis by GHH was confirmed by flow cytometric analysis of the DNA-stained cells. The percentage of apoptotic cells increased to 28%, 31% and 37% 24 hr and 37%, 44% and 81% 48 hr after treatment with 0.01, 0.1 and 1㎎/㎖ GHH, respectively. Flow cytometric analysis of GHH treated HL-60 cells showed increase of hypodiploid apoptotic cells in a dose- and time- dependent manner. DNA fragmentation also occurred in apoptosis and was characterized by a ladder pattern on agarose gel. In addition, GHH (0.01 and 0.1㎎/㎖) increased the secretion of tumor necrosis factor-alpha in 24 and 48 hr. The author showed that GHH-induced apoptosis was accompanied by activation of caspase-3. These results suggest that GHH induces activation of caspase-3 and eventually leads to apoptosis.

• 정보처리학회논문지B
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• 제11B권4호
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• pp.509-516
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• 2004

의미기반 이미지 검색에서의 의미적 내용 인식은 주석 위주의 텍스트 정보를 이용하는 것이 일반적이다. 이러한 텍스트 정보 기반 이미지 검색은 전통적인 검색 방법인 키워드 검색 기술을 그대로 사하여 쉽게 구현할 수 있으나, 텍스트의 개념적 매칭이 아닌 스트링 매칭이므로 주석 처리된 단어와 정확한 매칭이 없다면 검색할 수 없는 단점이 있었다. 이에 본 논문에서는 Ontology의 일종인 WordNet을 이용하여 깊이, 정보량, 링크 타입, 밀도 등을 고려한 단어간 의미 유사도를 측정하여 패턴 매칭의 문제점을 해결하고자 한다. 또한, 이미지의 컬러 분포 유사도를 측정하여 저차원 특징과 결합한 의미적 이미지 검색이 가능하도록 설계하였다. 제안된 검색 방안에 대해 'Microsoft Design Gallery Live'의 주석을 포함한 이미지를 대상으로 실험한 결과, 기존 의미기반 검색 시스템보다 향상된 결과를 확인하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.135-136
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• 2016

초고강 콘크리트를 활용한 부잔교는 강재부잔교에 비해 부식의 염려가 없어 내구성과 동적안전성이 우수하고, 일반 콘크리트에 비해 경량구조물로 건현확보가 유리하다. 현재 국내 연구개발 결과 SUPER concrete는 100MPa까지는 강섬유의 배합없이 일반골재만으로 배합이 가능하여 고부식성 환경의 항만구조물의 내구성에 적합한 강도이다. 부잔교는 상부슬래브에 작용하는 차량(DB-18) 또는 군집하중(5kN/m2)과, 외부 벽체 및 하부슬래브에 작용하는 파력의 수평과 양력성분을 견디도록 하여야 한다. 설계 파랑은 인천 연평도지역을 대상으로 50년 빈도 유의파와 주기에 해당하는 파력을 산정하여 X,Y축 위치에 따라 수평 및 양력성분을 재하하였다. 전체계 해석시 부잔교는 연직방향 경계조건이 없는 상태에서 부력 산정이 가능하도록 기하비선형 및 시간이력해석기법을 응용하였다(Strand 7). 부잔교 슬래브에 대해서는 실물모형실험을 통해 DB-18하중 재하에 따른 안전성을 확인하였다.

• 공학교육연구
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• 제7권3호
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• pp.44-50
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• 2004

수강자의 전공에 상관없이 어렵고 다양한 공학의 문제들을 쉽게 접근하도록 하는 강의를 소개한다. 이 강의는 공학에 대한 사전지식이나 경험을 요구하지 않는다. 반면에 기술과 동떨어져 생각할 수 없는 일상생활의 현재와 미래의 모습에 대한 강한 호기심과 상상력만을 수강자에게 요구한다. 강의를 통하여 바람직한 공학과 공학행위란 무엇인가 하는 공학의 기본적인 문제제기에 대해 수강자들이 고민해 볼 수 있도록 유도한다. 강의 주제가 공학의 다양한 면을 다루기 때문에 기존의 학습 방법은 효과적이거나 성공적이지 못하다. 이에 대한 대안으로 강의에서는 모의적인 사유실험과 물리적인 미디어 체험 등을 이용한 효과적인 학습법을 사용하였다. 선정된 공학적 주제에 따라 씌어진 시나리오를 구성하고 이 시나리오에 따라 짧은 영화 형식의 약 20개의 강의 컨텐츠를 만든다. 제작된 영상을 보면서 수강자들과 토론을 나누었다. 수강자의 흥미 유도를 위하여 로봇과 같은 미디어가 사용되었다. 온라인과 오프라인에서의 강의자와 수강자 사이의 인터액션 유도, 공학적 주제에 대한 적극적인 의견 개진을 유도하는 과제 수행, 강의 주제에 관련된 영상 제작 프로젝트 수행 및 평가 등 인터액티브한 공학개론 교육 사례로 부산대학교에서 시행된 지능공학 강의 경험을 소개한다.

• Fisheries and Aquatic Sciences
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• 제12권2호
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• pp.152-161
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• 2009

The largehead hairtail (Trichiurus lepturus) is one of the most common fisheries stocks in the East China Sea and the Yellow Sea. The species is caught using a variety of fishing tools, such as a stow net or a long line, as well as jigging and trawling. Scientific investigations have been conducted throughout the world to enable evidence-based estimations for the management and protection of the main fisheries biomass. For example, inshore and offshore hydro acoustic surveys are performed annually using bottom- and mid-water trawls around the Korean Peninsula. However, to date, no acoustic survey has been conducted to estimate fish size distribution, which is necessary to construct a data bank of target strength (TS) relative to fish species, length (L), and frequency. This study describes the frequency and length dependence of TS among fishes in Korean waters for the purpose of constructing such a TS data bank. TS measurements of the largehead hairtail were carried out in a water tank (L 5 m$\times$width 6 m$\times$ height 5 m) at frequencies of 50, 75, 120, and 200 kHz, using a tethering method. The average TS patterns were measured as a function of tilt angle, ranging from $-45^{\circ}$ (head down) to $+45^{\circ}$ (head up) every $0.2^{\circ}$. The length conversion constant ($b_{20}$) was estimated under the assumption that TS is proportional to the square of the length. In addition, in situ TS measurements on live largehead hairtails were performed using a split beam echo sounder.

• 한국산학기술학회논문지
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• 제21권5호
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• pp.426-432
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• 2020

20세기 이후 미디어의 발달과 함께한 음악은 이전 시대에서는 상상하기 힘들었던 대중들의 삶과 음악이 서로 함께하는 시대로 변화를 맞이하게 된다. 이러한 문화적 흐름을 바탕으로 기존 문화에서 철저히 소외되었던 10대들의 음악이 주류로 진입한 사건인 록큰롤의 탄생과 그 배경에는 기타, 그 중에서도 솔리드 바디 일렉트릭 기타의 출현과 그 맥을 같이 한다고 볼 수 있다. 이렇게 일렉트릭 기타의 대명사로 일컬어지는 펜더 스트라토케스터는 록큰롤을 위시한 대중음악의 역사와 함께했다 해도 과언이 아닐 것이다. 현재까지도 많은 추종자와 세대를 아우르는 폭넓은 지지를 받는 막강한 영향력은 대중음악의 역사적 흐름과 일렉트릭 기타의 위상에 있어서도 현재까지 끊임없이 재생산되는 가교 역할을 했다. 또한 대중음악과 미디어의 비약적인 발전 속에서도 언제나 현재진행형으로 도구를 넘어 시대와 함께 하는 생명력에 진정한 의미와 가치를 들 수 있을 것이다. 본 논문에서는 이러한 펜더 스트라토케스터의 특징과 흔적들이 어떻게 나타나는지 살펴보도록 한다.

• IMMUNE NETWORK
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• 제6권4호
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• pp.179-184
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• 2006

Background: Identification of antigen-specific T cells has yielded valuable information on pathologic process and the disease state. Assays for quantification of inflammatory cytokines or lytic-granule molecules have been generally used to evaluate antigen specific T cell response, however their applicability have been hampered due to the limited source of autologous antigen-presenting target cells (APC). Methods: K562, a leukemic cell line deficient of human leukocyte antigen (HLA), was transfected with a gene encoding HLA-A*02 (K562/ A*02) and its function as stimulator cells in inducing activation of HLA-matched T cells was evaluated by IFN-${\gamma}$ enzyme linked immunospot (ELISPOT) assay. Results: The stable transfectant K562/ A*02 pulsed with HLA- A*02 restricted peptide could specifically induce IFN-${\gamma}$ secretion by CD8+ T cells compared to no detectable secretion by CD4+ T cells. However, CD56+ NK cells secreted IFN-${\gamma}$ in both K562/ A*02 with peptide and without peptide. The number of IFN-${\gamma}$ secreted CD8+ T cells was increased according to the ratio of T cells to K562 and peptide concentration. Formalin-fixed K562/ A*02 showed similar antigen presenting function to live K562/ A*02. Moreover, K562/ A*02 could present antigenicpeptide to not only A*0201 restricted CD8+ T cells but also CD8+ T cells from A*0206 donor. Conclusion: These results suggest that K562/ A*02 could be generally used as target having specificity and negligible background for measuring CD8+ T cell responses and selective use of K562 with responsder matched HLA molecules on its surface as APC may circumvent the limitation of providing HLA-matched autologous target cells.

• International Journal of Oral Biology
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• 제35권2호
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• pp.43-49
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• 2010

Enterococcus faecalis, a gram-positive bacterium, has been implicated in endodontic infections, particularly in chronic apical periodontitis. Proinflammatory cytokines, including tumor necrosis factor-$\alpha$ (TNF-$\alpha$), are involved in the pathogenesis of these apical lesions. E. faecalis has been reported to stimulate macrophages to produce TNF-$\alpha$. The present study investigated the mechanisms involved in TNF-$\alpha$ production by a murine macrophage cell line, RAW 264.7 in response to exposure to E. faecalis. Both live and heat-killed E. faecalis induced high levels of gene expression and protein release of TNF-$\alpha$. Treatment of RAW 264.7 cells with cytochalasin D, an inhibitor of endocytosis, prevented the mRNA up-regulation of TNF-$\alpha$ by E. faecalis. In addition, antioxidant treatment reduced TNF-$\alpha$ production to baseline levels. Inhibition of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase also significantly attenuated E. faecalis-induced TNF-$\alpha$ expression by RAW 264.7 cells. Furthermore, activation of NF-${\kappa}B$ and AP-1 in RAW 264.7 cells was also stimulated by E. faecalis. These results suggest that the phagocytic uptake of bacteria is necessary for the induction of TNF-$\alpha$ in E. faecalis-stimulated macrophages, and that the underlying intracellular signaling pathways involve reactive oxygen species, ERK, p38 MAP kinase, NF-${\kappa}B$, and AP-1.