• Journal of Life Science
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• v.19 no.3
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• pp.305-310
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• 2009

Plasmid pGKV21 contains a 229-nucleotide (nt) single-strand DNA initiation (ssi) signal. Using asymmetric PCR, we prepared a small single-stranded (ss) DNA fragment of the ssi signal and, using the 229-nt ssDNA fragment, determined the requirements of RNA polymerase for priming and DNA-protein interaction. The ssi fragment prepared was able to generate primer RNAs with almost the same efficiency as the $M13{\Delta}lac182/229$ phage DNA. However, the cssi (complementary strand of the ssi signal) fragment could not synthesize primer RNAs. This result suggests that the 229-nt ssi signal functions in a strand specific manner. Gel retardation and DNase I footprinting demonstrated that the synthesized ssi fragment could interact with both E. coli RNA polymerase and SSB protein to synthesize primer RNA. In Escherichia coli [pWVAp], an addition of rifampicin resulted in an accumulation of ssDNA, indicating that the host-encoded RNA polymerase is involved in the conversion of ssDNA to double-stranded plasmid DNA.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.797-802
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• 2008

High Speed Rail Train Control System consists of CTC, IXL and ATC. IXL and ATC perform train control and command via interchanging relevant information between a signal room and CTC. However, it is proved that IXL and ATC are attributed to train delay error since those systems are highly sensitive to trackside conditions. Especially, network error on IXL blocks transmitting signal information to adjacent signal room so that its effects give rise to system overall problems. In order to figure out the measures for which minimizing the occurrence rate of train delay error due to HSR TCS, This paper is performed analysis on communication network structure, the length of SSI network roof and SSI-TFM distance by examining and analyzing the error cases related to IXL in a network aspect.

• BMB Reports
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• v.28 no.4
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• pp.336-341
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• 1995

Using a mutant M13 phage derivative lacking a great part of the complementary strand synthesis origin, we identified six single-strand initiation (ssi) signals for DNA replication in pACYC184, pLG214, pGKV21, and pDPT270 plasmids, and named them $ssiA_{YC}$, $ssiA_{LG}$, $ssiB_{LG}$, $ssiA_{KV}$, $ssiA_{PT}$, and $ssiB_{PT}$, respectively. Two of them were from pDPT270, one from downstream the on of pACYC184, two from pLG214, one from upstream the plus origin of pGKV21. Introduction of these ssi signals into the deleted $ori_c$ site of a mutant filamentous M13 phage ($M13{\Delta}lac182$) resulted in the restoration of growth activity of this phage. These ssi signals were classified into a number of groups on the basis of sequence similarity. $ssiA_{YC}$ and $ssiA_{LG}$ show extensive sequence homology to the n'-site (primosome assembly sites) of ColE1, whereas $ssiB_{PT}$ is homologous to the n'-site of ${\Phi}X174$. $ssiA_{PT}$ belongs to G4-type ssi signals which require only dnaG primase and SSB protein for the priming of replication. In addition, possible biological roles of these ssi signals are discussed.

• Smart Structures and Systems
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• v.10 no.4_5
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• pp.331-351
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• 2012

In this study an output-only system identification technique for civil structures under ambient vibrations is carried out, mainly focused on using the Stochastic Subspace Identification (SSI) based algorithms. A newly developed signal processing technique, called Singular Spectrum Analysis (SSA), capable to smooth a noisy signal, is adopted for preprocessing the measurement data. An SSA-based SSI algorithm with the aim of finding accurate and true modal parameters is developed through stabilization diagram which is constructed by plotting the identified system poles with increasing the size of data matrix. First, comparative study between different approaches, with and without using SSA to pre-process the data, on determining the model order and selecting the true system poles is examined in this study through numerical simulation. Finally, application of the proposed system identification task to the real large scale structure: Canton Tower, a benchmark problem for structural health monitoring of high-rise slender structures, using SSA-based SSI algorithm is carried out to extract the dynamic characteristics of the tower from output-only measurements.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.48-53
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• 2000

In this paper, we develop a TMS320C31 (60MHz) digital signal processor (DSP) board to synthesize gradient waveforms for Spiral Scan Imaging (SSI), which is one of the ultra fast magnetic resonance imaging (MRI) methods widely used. In SSI, accurate gradient waveforms are very essential to high quality magnetic resonance images. For this purpose, sampling rate for synthesizing the gradient waveforms is set twice as high as the data sampling rate. With the developed DSP boards accurate gradient waveforms are obtained. Ultra fast spiral scan imaging with the developed with the developed DSP board is currently under development.

• Smart Structures and Systems
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• v.29 no.3
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• pp.499-512
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• 2022

This work proposes a novel contactless vibration damping and thermal isolation tripod platform based on Superconducting Magnetic Levitation (SML). This prototype is suitable for cryogenic environments, where classical passive, semi active and active vibration isolation techniques may present tribological problems due to the low temperatures and/or cannot guarantee an enough thermal isolation. The levitating platform consists of a Superconducting Magnetic Levitation (SML) with inherent passive static stabilization. In addition, the use of Operational Modal Analysis (OMA) technique is proposed to characterize the transmissibility function from the baseplate to the platform. The OMA is based on the Stochastic Subspace Identification (SSI) by using the Expectation Maximization (EM) algorithm. This paper contributes to the use of SSI-EM for SML applications by proposing a step-by-step experimental methodology to process the measured data, which are obtained with different unknown excitations: ambient excitation and impulse excitation. Thus, the performance of SSI-EM for SML applications can be improved, providing a good estimation of the natural frequency and damping ratio without any controlled excitation, which is the main obstacle to use an experimental modal analysis in cryogenic environments. The dynamic response of the 510 g levitating platform has been characterized by means of OMA in a cryogenic, 77 K, and high vacuum, 1E-5 mbar, environment. The measured vertical and radial stiffness are 9872.4 N/m and 21329 N/m, respectively, whilst the measured vertical and radial damping values are 0.5278 Nm/s and 0.8938 Nm/s. The first natural frequency in vertical direction has been identified to be 27.39 Hz, whilst a value of 40.26 Hz was identified for the radial direction. The determined damping values for both modes are 0.46% and 0.53%, respectively.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.1
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• pp.1-14
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• 2023

Underwater images carry information that is useful in the fields of aquaculture, underwater military security, navigation, transportation, and so on. In this research, we transmitted an underwater image through various underwater mediums in the presence of underwater turbulence and beam attenuation effects using a high-speed visible optical carrier signal. The optical beam undergoes scintillation because of the turbulence and attenuation effects; therefore, distorted images were observed at the receiver end. To understand the behavior of the communication media, we obtained the bit error rate (BER) performance of the system with respect to the average signal-to-noise ratio (SNR). Also, the structural similarity index (SSI) and peak SNR (PSNR) metrics of the received image were evaluated. Based on the received images, we employed suitable nonlinear filters to recover the distorted images and enhance them further. The BER, SSI, and PSNR metrics of the specific nonlinear filters were also evaluated and compared with the unfiltered metrics. These metrics were evaluated using the on-off keying and binary phase-shift keying modulation techniques for the 50-m and 100-m links for beam attenuation resulting from pure seawater, clear ocean water, and coastal ocean water mediums.

• The Journal of the Acoustical Society of Korea
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• v.40 no.2
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• pp.161-168
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• 2021

In this paper, a Silent Speech Interface (SSI) technology was proposed in which Doppler frequency shifts of the reflected signal were used to synthesize the speech signals when 40kHz ultrasonic signal was incident to speaker's mouth region. In SSI, the mapping rules from the features derived from non-speech signals to those from audible speech signals was constructed, the speech signals are synthesized from non-speech signals using the constructed mapping rules. The mapping rules were built by minimizing the overall errors between the estimated and true speech parameters in the conventional SSI methods. In the present study, the mapping rules were constructed so that the distribution of the estimated parameters is similar to that of the true parameters by using Generative Adversarial Networks (GAN). The experimental result using 60 Korean words showed that, both objectively and subjectively, the performance of the proposed method was superior to that of the conventional neural networks-based methods.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.25-28
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• 2000

시변 특성을 갖는 무선 채널 환경에서 UEP(Unequal Error Protection) 채널 부호화 방법은 효율적인 정보 전송을 가능케 한다. 본 논문에서는 IP-SCCC (Interleaved Puncturing Serially Concatenated Convolutional Codes)로 CSI(Channel State Information)와 SSI(Source Significance Information)를 이용한 두가지 UEP 채널 부호화 방법을 제안한다. 또한 AWGN(Additive White Gaussian Noise)과 Rayleigh 페이딩이 존재하는 채널을 가정하고 모의 실험을 통해 알고리즘의 우수성을 검증한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.131-138
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• 2016

In this study, we tried to analyze the influence of ICM(Iodinated Contrast Media) in MR imaging compare to GBCA(Gadolinium Based Contrast Agent), and as this result we discussed whether resonable or not the protocol which is MRI scan after enhanced CT scan without proper time interval in clinical field. For this research, we assembled two phantoms. which one was iodine and another one was gadolinium. We did test two phantoms in conventional MRI scan which is T1, T2, T2 FLAIR and 3D angio. After that, quantitative analysis was progressed. The results of study were as follow : SSI(Saline's Signal Intensity) was shown as each sequences 175, 1231, 333, 37 [a.u] at iodine. and 1297, 123, 757, 232 [a.u] was recorded at gadolinium. BDEPS(the Biggest Difference of EPS) was shown as each sequences 1297, 123, 757, 232 [a.u] at iodine and 793, 6, 1495, 365 [a.u] was recorded at gadolinium. At this time, EPS(Enhancement Percentage to Saline) was shown 641.1, -90.0, 127.3, 527% at iodine and 685.1, 99.4, 365.7, 1077.4% was recorded at gadolinium. BP(BDEPS's point) was shown 900, 900, 477, 900 mmol at iodine and 4, 0.2, 0.2, 40 mmol was recorded at gadolinium. CPSS(Change Point of SI to SSI) was shown 63, 423, 63, 29 mmol at iodine and each [50, 30], [4, 0.2], [4, 1], 0.2 mmol was recorded at gadolinium. According to this research, we could not only discover the fact that was iodine could effect on MR signal, but also the pattern is different as various sequences compare to gadolinium. Therefore, we expect useful diagnostic MR image in clinical field with this quantitative data for deciding protocol regarding MRI and CT scan order.