• BMB Reports
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• v.45 no.11
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• pp.629-634
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• 2012

The human glycoprotein, stanniocalcin 2 (STC2) plays multiple roles in several tumor types, however, its function and clinical significance in hepatocellular carcinoma (HCC) remain unclear. In this study, we detected STC2 expression by quantitative real-time PCR and found STC2 was upregulated in HCC tissues, correlated with tumor size and multiplicity of HCC. Ectopic expression of STC2 markedly promoted HCC cell proliferation and colony formation, while silencing of endogenous STC2 resulted in a reduced cell growth by cell cycle delay in G0/G1 phase. Western blot analysis demonstrated that STC2 could regulate the expression of cyclin D1 and activate extracellular signal-regulated kinase 1/2 (ERK1/2) in a dominant-positive manner. Transwell chamber assay also indicated altered patterns of STC2 expression had an important effect on cell migration. Our findings suggest that STC2 functions as a potential oncoprotein in the development and progression of HCC as well as a promising molecular target for HCC therapy.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1029-1039
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• 2013

To avoid undesirable disconnection of healthy wind generators (WGs) or a wind power plant, a WG protection relay should discriminate among faults, so that it can operate instantaneously for WG, connected feeder or connection bus faults, it can operate after a delay for inter-tie or grid faults, and it can avoid operating for parallel WG or adjacent feeder faults. A WG protection relay based on the positive- and negative-sequence fault components is proposed in the paper. At stage 1, the proposed relay uses the magnitude of the positive-sequence component in the fault current to distinguish faults requiring non-operation response from those requiring instantaneous or delayed operation responses. At stage 2, the fault type is first determined using the relationships between the positive- and negative-sequence fault components. Then, the relay differentiates between instantaneous operation and delayed operation based on the magnitude of the positive-sequence fault component. Various fault scenarios involving changes in position and type of fault and faulted phases are used to verify the performance of the relay. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. Results indicate that the relay can successfully distinguish the need for instantaneous, delayed, or non-operation.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.519-527
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• 2017

Excessive activation of microglia causes the continuous production of neurotoxic mediators, which further causes neuron degeneration. Therefore, inhibition of microglial activation is a possible target for the treatment of neurodegenerative disorders. Balanophonin, a natural neolignoid from Firmiana simplex, has been reported to have anti-inflammatory and anti-cancer effects. In this study, we aimed to evaluate the anti-neuroinflammatory effects and mechanism of balanophonin in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. BV2 microglia cells were stimulated with LPS in the presence or absence of balanophonin. The results indicated that balanophonin reduced not only the LPS-mediated TLR4 activation but also the production of inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), $Interleukin-1{\beta}$ ($IL-1{\beta}$), and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), in BV2 cells. Balanophonin also inhibited LPS-induced inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) protein expression and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 MAPK. Interestingly, it also inhibited neuronal cell death resulting from LPS-activated microglia by regulating cleaved caspase-3 and poly ADP ribose polymerase (PARP) cleavage in N2a cells. In conclusion, our data indicated that balanophonin may delay the progression of neuronal cell death by inhibiting microglial activation.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.3
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• pp.31-39
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• 2014

In KSLV-I launch mission, real-time data from the tracking stations are acquired, processed and distributed by the Mission Control System to the user group who needed to monitor processed data for safety and flight monitoring purposes. The processed trajectory data by the mission control system is sent to each tracking system for target designation in case of tracking failure. Also, the processed data are used for decision making for flight termination when anomalies occur during flight of the launch vehicle. In this paper, we propose the processing mechanism of slaving data which plays a key role of launch vehicle tracking mission. The best position data is selected by predefined logic and current status after every available position data are acquired and pre-processed. And, the slaving data is distributed to each tracking stations through time delay is compensated by extrapolation. For the accurate processing, operation timing of every procesing modules are triggered by time-tick signal(25ms period) which is driven from UTC(Universial Time Coordinates) time. To evaluate the proposed method, we compared slaving data to the position data which received by tracking radar. The experiments show the average difference value is below 0.01 degree.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.145-149
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• 1980

Various methods have been so far proposed to find out the directions and spectra of sound waves from the sources for provisions of noise controls. The conventional methods are generally classified into three systems such as, single microphone system, moving microphone system and multi-microphone system, which composes a resultant super directivity by giving a appropriate delay and a weighting coefficient in the output of each microphone. In case of using a single microphone there is a difficulty in providing it with desirable super directivity in the low frequency range, while in case of using multi-microphone system there has been a disadvantage that the measurement of directivity could not separately be done with the spectrum analysing. And in case of the use of a moving microphone system it needs a condition that the sound source to be detected should be stationary state and in rest. However here we introduce a method that the spectral analysing and the directivity of synthesis can be separately carried out by using a linear array of many microphones, in which each output of the microphone is multiplied by appropriate weighting coefficient and all of those products are summed after passing through adequate filters. The resultant signal is then sampled with an adequate sampling frequency and taken average for processing.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.125-133
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• 2004

Most of the way shape estimation method using reference sources assume that the reference sources are in the farfield. That is, the reference sources are assumed to be far from the array. However, in applications of the array with reference sources, the reference sources are not far from the way, so that in practical ocean environments, the conventional method using farfield source model fail to estimate the positions of the hydrophones. In this paper, based on the nearfield source model, a subspace-based array shape estimation method was proposed. In the proposed method, nearfield reference source is modeled using the differential time delay at each hydrophone, and nearfield parameters are derived. Using these parameters, a subspace-based array shape estimation method that generalizes the existing farfield subspace fitting method which can work regardless of the range of the source is proposed. The Cramer-Rao lower bound for the proposed method is investigated. The results of the numerical experiments indicate that the proposed method performs well in estimating the shape of a perturbed way regardless of the ranges of the reference sources.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2295-2303
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• 2009

Underwater acoustic(UWA) communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of UWA channel causes signal distortion and error floor. In this paper, we proposed the compensation method of multipath effect using the impulse response of the UWA channel and then analysis the performance of channel coding such as LDPC code, concatenate code. Also we analysed the time-delay errors and estimated amplitude errors of estimated channel information and its affection on the performance. As shown in simulation results, the performance of proposed compensation method is better than the performance of conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2232-2240
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• 2017

IMO has made AIS and VHF mandatory for international sailing vessels through SOLAS, and korea if mandating specific vessels through the law for safety of vessels and the ship installation technology standards. However, due to various communication equipments and complicated usage method, malfunction occurs, and the response delay to the actual structure signal often causes human accidents. So recently, as a part of GMDSS modernization, maritime communication devices are attempting to interwork and integrate different types of marine communication system in order to construct a next generation maritime communication system. In this paper, we describe a technique to implement the DSC function by interlocking and integrating the AIS device and VHF. We will present the basis for achieving domestic technical standards and standardization through the linking algorithm of the data that can extract the ship information from AIS and utilize it the DSC function of VHF.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.529-536
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• 2003

In this Paper, a new DCT HLMS DFE(Discrete Cosine Transform Hierarchical Least Mean Square Decision Feedback Equalizer) algorithm is proposed to improve the convergence speed and MSE(Mean Square Error) performance of a receive channel equalizer in ATSC(Advanced Television System Committee) 8VSB(Vestigial Side Band) digital terrestrial TV system. The proposed algorithm reduces the eigenvalue range of input data autocorrelation by transforming LMS (Least Mean Square) DFE into the subfilter of hierarchical structure. Moreover, the use of DCT and power estimation algorithm makes it possible to reduce the eigenvalue deviation of input data which results from distortion and delay of the receive signal in the miulti-path environment. Simulation results show that proposed DCT HLMS DFE has SNR improvement of approximately 3.8dB, 5dB and 2dB as compared to LMS DFE when the equalized symbol error rate is 0.2 in ATTC defined digital terrestrial TV broadcasting channels A, B and F, respectively.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.143-150
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• 2011

Roundabouts, which belong to traffic circles, are intersections which are similar to the existing rotary form. Roundabouts recently have been constructed all around the world. And interests in roundabouts are increasing in Korea. However, there are lacks of research on pedestrian volume which has a great influence on operation efficiency of roundabouts in urban area. Therefore, this study suggests efficiency analysis and pedestrian signals in roundabouts according to the pedestrian volume. First, VISSIM simulation was organized to analyse volume of one lane roundabouts in urban area. Second, average delay of intersections was calibrated by VISSIM simulation dividing signalized intersections and non-signalized intersections depending on pedestrian volume. Finally, this study showed that roundabouts are suitable when pedestrian volume was under 200person/hr and traffic circles with a pelican signal are suitable when pedestrian volume was over 200person/hr. And when pedestrian volume and traffic volume are over 600person/hr and 1,500vph respectively, fixed signalized intersections fit well.