• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.57-65
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• 2015

The Potential Induced Degradation(PID) in PV module mainly affected by various performance conditions such as a potential difference between solar cell and frame, ambient temperature and relative humidity. The positive charges as sodium ions in front glass reach solar cell in module by a potential difference and are accumulated in the solar cell. The ions accelerate the recombination of generation electrons within solar cell under illumination, which reduces the entire output of module. Recently, it was generally known that PID generation is suppressed by controlling the thickness of SiNx AR coating layer on solar cell or using Sodium-free glass and high resistivity encapsulant. However, recovery effects for module with PID are required, because those methods permanently prevent generating PID of module. PID recovery method that voltage reversely applies between solar cell and frame contract to PID generation begins to receive attention. In this paper, PID recovery tests by using voltage under various outdoor conditions as humidity, temperature, voltage are conducted to effectively mitigate PID in module. We confirm that this recovery method perfectly eliminates PID of solar cell according to repeative PID generation and recovery as well as the applied voltage of three factors mainly affect PID recovery.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1442-1450
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• 1999

In this paper, we present an efficient hardware architecture for the frame memory of the MPEG-2 video encoder. Both the total size of internal buffers and the number of logic gates are reduced by the proposed memory map which can provide an effective interface between MPEG-2 video encoder and the external DRAM. Furthermore, the proposed scheme can reduce the DRAM access time. To realize the frame memory hardware,$0.5\mu\textrm{m}$, VTI, vemn5a3 standard cell library is used. VHDL simulator and logic synthesis tool are used for hardware design and RTL (register transfer level) function verification. The frame memory hardware emulator of the proposed architecture is designed for gate-level function verification. It is expected that the proposed frame memory hardware using VHDL can achieve suitable performance for MPEG-2 MP@ML.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.19-22
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• 2005

In order to achieve high capacity and reliable link quality in user communication, this paper proposes a new concept of virtual cell: the Dual Virtual Cell(DVC), and DVC employment strategy based on DWCS. The proposed system uses two kinds of virtual cell. One is the AVC(Active Virtual Cell) which exists for actual traffic and the other is the CVC(Candidate Virtual Cell) which contains a set of candidate antennas to protect user's link quality from performance degradation or interruption. And also this system aims to reduce MT's overloads and acheive a prompt link change successfuly by introducing DVC structure which makes it possible for network to monitor real-time channel and to conrol communication links. The proposed system constructs DVC by using antenna selection method and improves frame error performance with employing Space-Time Trellis Code(STTC).

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.61-70
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• 2011

IEEE 802.11 wireless network supports control frames like RTS/CTS(Request To Send / Clear To Send). Because they is defend to frame collection problems. It helps to solve the frame collection problem but decreases the throughput rate. Also, control frame makes False Node Problem. This problem is makes to other wireless nodes don't work and don't find channels in the same cell and near cells. We proposed a reformed new control frame for efficiency throughput rate and solution of False Node Problem. New control frame is to have added to 4 bytes of channel detection ability at the RTS frames. Channel detection ability supported to check channel at the wireless node start to transmit data frame, We expect that channel detection ability make prevent False Node Problem for increase to access number to channel. We perform comparative analysis in terms of delay(sec) and load(bits/sec) with reform RTS/CTS method which proves the efficiency of the proposed method.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.305-310
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• 2003

The performance of various GFR implementations has been recently studied due to the interest to provide bandwidth guarantees with a simpler implementation than ABR in ATM networks. One of the important factors is buffer management for guaranteeing QoS in GFR service. An efficient buffer management algorithm is necessary to guarantee MCR for untagged cell in ATM switch. In this paper, we propose and evaluate a buffer management scheme to provide the GFR service guarantees. The proposed scheme can control the cell discarding for fairness in each VC, and compared with Double-EPD and DFBA. Our results show that the proposed buffer management with per-VC queuing achieves significant enhancement on goodputs and fairness index than those of existing methods.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.595-602
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• 2003

In this paper, we proposed new buffer management and cell scheduling scheme of GFR service for improving fairness of TCP/IP traffic in ATM networks. The proposed algorithm used untagged cell, which came to ATM switch, to decide the policy for discard of frame and what kind of VC cell it would serve. Performance analysis through the simulation present that proposed scheme can meet fairness 2 (MCR Plus equal share), which are not met by conventional scheduling mechanism such as WRR. Also, proposed scheme is superior to WRR about 30% in throughput and more efficiency in fairness criteria.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.622-632
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• 2004

We have studied how liquid crystal's rubbing direction and voltage driving method affect generation of disclination line. At first, generation of disclination line in vertical alignment(VA) cell and VA-twisted nematic(TN) cell has been examined. When liquid crystal's rubbing direction of bottom substrate was 0$^{\circ}$, the degree of generated disclination line was the smallest value. Further, the generation of disclination line above the electrode is less in the frame inversion than in the line inversion. Secondly, we have examined a generation of disclination line in reflective fringe-field switching cell. When the distance between common electrodes is over 3 ${\mu}{\textrm}{m}$ with on-state of one pixel and off-state of neighboring pixels, the reflectance appears only on-state pixel without generating reflectance in adjacent pixels.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4589-4592
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• 2015

Background: Missense and frame-shift mutations within the dimer forming domain of the caspase 8 gene have been identified in several cancers. However, the genetic status of this region in precancerous lesions, like oral submucous fibrosis (OSMF), and well differentiated oral squamous cell carcinomas (OSCCs) in patients from southern region of India is not known, and hence the present study was designed to address this issue. Materials and Methods: Genomic DNA isolated from biopsy tissues of thirty one oral submucous fibrosis and twenty five OSCC samples were subjected to PCR amplification with intronic primers flanking exon 7 of the caspase 8 gene. The PCR amplicons were subsequently subjected to direct sequencing to elucidate the status of mutation. Results: Sequence analysis identified a frame-shift and a novel missense mutation in two out of twenty five OSCC samples. The frame-shift mutation was due to a two base pair deletion (c.1225_1226delTG), while the missense mutation was due to substitution of wild type cysteine residue with phenylalanine at codon 426 (C426F). The missense mutation, however, was found to be heterozygous as the wild type C426C codon was also present. None of the OSMF samples carried mutations. Conclusions: The identification of mutations in OSCC lesions but not OSMF suggests that dimer forming domain mutations in caspase 8 may be limited to malignant lesions. The absence of mutations in OSMF also suggests that the samples analyzed in the present study may not have acquired transforming potential. To the best of our knowledge this is the first study to have explored and identified frame-shift and novel missense mutations in OSCC tissue samples.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.103-105
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• 2008

In grid-interconnection system, a fast, robust and precise phase angle detector is most important to grid synchronization and the active power control. The phase angle can be easily estimated by synchronous dq PLL system. On the other hand under unbalanced voltage condition, synchronous dq PLL system has problem that harmonics occur to phase angle or magnitude of grid voltage because of the effect of the negative sequence components. So, To eliminate the negative sequence components, the PLL method using APF (All Pass Filter) in a stationery reference frame to extract positive sequence components under unbalanced voltage condition is researched. In this paper, we propose a new PLL method with decoupling network using APF in a synchronous reference frame to extract the positive sequence components of the grid voltage under unbalanced grid. The cut-off frequency of APF in a synchronous reference frame can be set to twice of the fundamental frequency comparing with that of APF in a stationery reference frame which is the fundamental frequency. The proposed PLL strategy can detect the phase angle quickly and accurately under unbalanced gird voltages. Simulation and experimental results are presented to verify the proposed strategy under different kind of voltage dips.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.591-594
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• 2001

In the W-CDMA system, cell search is one of the imporant functions of the mobile station searching for a cell and achieving spreading code and time synchronization to its downlink scrembling code. For the methods of cell search to optimize codes, three stages are considered: 1) slot synchronization, 2) frame synchronization, and 3) scrambling code identification. Channels for cell search are Primary Synchronization Channel (P-SCH), Secondary Synchronization Channel(S-SCH), and Common Pilot Channel (CPICH). In this paper, cell search is analyzed based on simulation. Rake receiver provides improvement of Performance as an increase of bandwidth because there are more available multipaths. In this paper, the performance of W-CDMA system employing RAKE receiver is evaluated by computer simulation over the types of ITU_R wideband channel model and spreading rate. The result shows that the performance of CDMA adapting RAKE receiver is improved by the increase of multipath components in equal level of the received power.