• 한국기계가공학회지
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• 제12권5호
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• pp.157-162
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• 2013

To analyze the dynamic acceleration characteristics, it is necessary to identify the acceleration model using some methods that can represent the dynamic properties well. In this sense, fractal methods were used for the verification of characteristics of an acceleration signal. To estimate and analyze the geometry of acceleration signal, a fractal interpolation and its analysis was introduced in this paper. The chaotic nature of acceleration signal was considered in fractal modeling. In this study the fractal signal modeling has brought a focus within the scope of the fractal interpolation and fractal dimension. And a new idea of fractal dimension has been introduced and discussed considering the damping ratio and amplitude for its dynamic properties of the signal. The fractal dimension of acceleration with respect to the scaling factor using fixed data points of 1000 points was calculated and discussed. The acceleration behaviors of this results show some different characteristics. And this fractal analysis can be applied to other signal analysis of several machining such as pendulum type grinding and milling which has many dynamic properties in the signal.

• Biomolecules & Therapeutics
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• 제7권4호
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• pp.329-334
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• 1999

Recently, cellular signal transduction mechanisms are greatly understood. However, bone cell signaling is not completely characterized. Interestingly, bone cells synthesize a number of growth factors such as IGF-I PDGF, IGF-II etc., suggesting these growth factors play important roles in bone cell signaling. In the present study, potential roles of nitric oxide (NO) and protein kinases in osteoblast signal transduction are proposed.

• BMB Reports
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• 제32권1호
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• pp.28-32
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• 1999

Annexin I (also called lipocortin 1), a 37-kDa member of the annexin family of proteins, has been implicated in the mitogenic signal transduction by epidermal growth factor (EGF). Annexin I is phosphorylated by the EGF signal, however, the role of annexin I in the EGF signal transduction is still unknown. To transduce extracellular signals into the intracellular targets, selective translocation of the signaling molecules to their targets would be necessary. In this study, we examined the subcellular locations of annexin I during EGF signal transduction. Treatment of A549 cells with EGF resulted in the translocation of cytoplasmic annexin I to the nucleus and perinuclear region as determined by Western blot and immunofluorescent staining. The nuclear translocation of annexin I was inhibited by tyrphostin AG 1478 and genistein, the inhibitors of EGF receptor kinase and downstream tyrosine kineses, respectively. Pretreatment of cells with cyclohexamide did not inhibit the nuclear translocation. The results suggest that nuclear translocation of annexin I is controlled by a series of kinase dependent events in the EGF receptor signaling pathway and may be important in tranducing the signals by EGF.

• Journal of Microbiology
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• 제44권2호
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• pp.217-225
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• 2006

Kaposi's sarcoma-associated herpesvirus (KSHV) RTA transcription factor is recruited to its responsive elements through interaction with RBP-Jk that is a downstream transcription factor of the Notch signaling pathway that is important in development and cell fate determination. This suggests that KSHV RTA mimics cellular Notch signal transduction to activate viral lytic gene expression. Here, I demonstrated that unlike other B lymphoma cells, KSHV -infected primary effusion lymphoma BCBL1 cells displayed the constitutive activation of ligand-mediated Notch signal transduction, evidenced by the Jagged ligand expression and the complete proteolytic process of Notch receptor I. In order to investigate the effect of Notch signal transduction on KSHV gene expression, human Notch intracellular (hNIC) domain that constitutively activates RBP-Jk transcription factor activity was expressed in BCBL1 cells, TRExBCBL1-hNIC, in a tetracycline inducible manner. Gene expression profiling showed that like RTA, hNIC robustly induced expression of a number of viral genes including KS immune modulatory gene resulting in downregulation of MHC I and CD54 surface expression. Finally, the genetic analysis of KSHV genome demonstrated that the hNIC-mediated expression of KS during viral latency consequently conferred the downregulation of MHC I and CD54 surface expression. These results indicate that cellular. Notch signal transduction provides a novel expression profiling of KSHV immune deregulatory gene that consequently confers the escape of host immune surveillance during viral latency.

• BMB Reports
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• 제38권1호
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• pp.1-8
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• 2005

Transforming growth factor-$\beta$ is a pleiotropic growth factor that has enthralled many investigators for approximately two decades. In addition to many reports that have clarified the basic mechanism of transforming growth factor-$\beta$ signal transduction, numerous laboratories have published on the clinical implication/application of transforming growth factor-$\beta$. To name a few, dysregulation of transforming growth factor-$\beta$ signaling plays a role in carcinogenesis, autoimmunity, angiogenesis, and wound healing. In this report, we will review these clinical implications of transforming growth factor-$\beta$.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 추계학술발표회
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• pp.181-186
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• 2006

정지궤도위성은 태양 궤도위성과는 달리 넓은 지역의 매시간 측정이 가능하다. 정지 위성은 관측영역은 항상 고정되어 있으나 태양의 위치가 항상 변하므로 한 주어진 지점의 해수 신호의 크기는 기간에 따라 변하게 된다. 반면에 태양 궤도 위성은 하루 통일한 시간대에서 동일한 영역을 촬영하기 때문에 신호의 크기의 변화가 없다. 즉, 정지해양 위성에서 관측된 신호의 크기는 태양과 위성이 항상 수직 방향에 위치한다고 가정할 때 얻어지는 신호의 크기로 변경되어야한다. 이와 같은 신호의 보정은 지속적으로 변화하는 태양, 위성과 관측점의 기하학적인 위치변화에 따라 나타나게 되는데 이를 양방향 계수 (Bidirectional Factor) 라고 한다. 본 연구에서는 태양의 위치와 기하학적인 요인을 계산, 대기권 밖의 총 방사휘도와 반사율을 계산하였다. 그리고 양방향계수, 즉 관측점과 관측지점 사이의 규격화된 해면방사휘도$([L_W]_N)$의 비를 모의실험을 통해 확인하였다. 1년간의 값을 영상화 하였고 보다 정확한 양방향 계수 (Bidirectional Factor)를 얻기 위해 다양한 조건의 모의실험의 필요성을 제시하였다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2007년도 High Temperature Superconductivity Vol.XVII
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• pp.56-56
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• 2007

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.416-418
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• 2006

In this paper, a new acoustic echo cancellation approach based on the DUET algorithm and scaling factor estimation is proposed to solve the scaling ambiguity in case of blind separation based acoustic echo cancellation in a noisy environment. In hands-free full-duplex communication system. acoustic noises picked up by the microphone are mixed with echo signal. For this reason, the echo cancellation system may provide poor performance. For that purpose, a degenerate unmixing estimation technique, adjusted in the time-frequency domain, is employed to separate undesired echo signals and noises. Also, since scaling and permutation ambiguities have not been solved in the blind source separation algorithm, kurtosis for the desired signal selection and a scaling factor estimation algorithm are utilized in this rarer for the separation of an echo signal. Simulation results demonstrate that the proposed approach yields better echo cancellation and noise reduction performances, compared with conventional methods.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.113-122
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• 2011

This paper introduces and develops an efficient method for measuring power factor (PF) and its nature under nonlinear load current situations. The method is based on generating a pulse width modulated signal whose width correlates to the value of PF. This signal can then be employed as a feedback signal for controlling PF related power quantities in a system. This method has the advantages of its simple implementation, less computational complexity, and its allowable error of less than 4[%], which is justified by the computer simulation results.

• KSBB Journal
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• 제23권5호
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• pp.460-462
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• 2008

개화시기의 수술로부터 수집한 백합화분을 aluminum oxide 미세입자와 섞어 교반에 의해 상해를 발생시켰다. 이어서 이들 화분은 signal peptide-fused epidermal growth factor (EGF) DNA를 지니는 Agrobacterium 세포로 vacuum infiltration을 시켰으며 24 hr 화분신장을 통한 배양을 실시하였다. 이들 신장 화분에서의 EGF mRNA 및 단백질 발현은 성공적으로 확인되었으며 이는 cDNA blot hybridization 및 immuno-blotting의 분석결과이다.