• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.23-29
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• 2004

This paper deals with Reed-Solomon Coding for EUROFIX system EUROFIX is an integrated navigation and communication system, which combines Differential GNSS and Loran-C EUROFIX transmits DGNSS(Differential Global Navigation Satellite Systems) (data by pulse position modulation of Loran-C pulses. Loran-C system is regarded as a satellite backup system in recent. And now, it is important to detect and correct much errors in communication systems. Error corrections or correction algorithm is actively studied nowadays because of this. In this paper, we study and design encoder and decoder of Reed Solomon Code using Finite Galois Field Fourier Transformation for error corrections in EUROFIX data transmission. Through extensive simulation, the designed Reed Solomon code is shown to be effective for error correction in EUROFIX data transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1138-1147
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• 2012

IEEE standard 802.16, often referred to as WiMAX, is considered a "last mile" broadband wireless access alternative to conventional DSL and Cable Internet. One extension that is recently receiving great attention is the IEEE 802.16j Mobile Multihop Relay (MMR) amendment. The focus of this amendment is the development of simple and lower cost relay stations (RSs) that can enhance network coverage and capacity. We use our proposed simple scheduling scheme for serving the SSs in a fair manner and evaluate the performance of WiMAX networks with relays, especially we analyze the impact of interference between RSs on cell throughput Through simulations and numerical analysis, we make several fundamental observations about interference aware cost effective coverage extension in such networks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.71-75
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• 2015

Nicotinic acetylcholine receptors (nAChRs) are essential for neurotransmission and important therapeutic targets of diseases related to neurotransmission. A recent experimental study identified three residues (Lys185, Asp187, and Ile188) of the ${\alpha}6$ nAChR subunit as determinants of ${\alpha}$-conotoxin BuIA selectivity, yet how these residues confer toxin selectivity remains unclear. In this study, we performed all-atom molecular dynamics simulations with two toxin-bound ${\alpha}4{\beta}2$ nAChR systems: the wild-type ${\alpha}4{\beta}2$ and one in which we replaced the three ${\alpha}4$ subunit residues with three ${\alpha}6$ subunit residues identified in an experimental study (Tyr185Lys, Thr187Asp, and Arg188Ile). After mutation, Asp199 lost the salt bridge formed with Arg188 in the wild type located around loop C. Then, the loop C conformation changed and became more flexible than that of the wild type. We also detected reduced space between the toxin and the binding site in the mutant simulation, resulting in increased binding affinity to the toxin. Therefore, we propose a new Asp199 mutation that breaks the salt bridge and may produce similar selectivity to that of the Arg188 mutation.

• Progress in Superconductivity
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• v.8 no.2
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• pp.143-151
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• 2007

Accurate measurements of the microwave surface resistance (Rs) of high temperature superconductor (HTS) films are important with regard to applications of HTS materials for wireless communications. As the surface resistance values of HTS films are usually extracted from the measured unloaded quality factor ($Q_0$) of resonators made of HTS films, it is essential to measure the resonator $Q_0$ with accuracy. The $TE_{011}\;mode\;Q_0$ of sapphire resonators with the endplates made of $YBa_2Cu_3O_{7-{\delta}}$(YBCO) film on $LaAlO_3$ is measured by using the S-parameter circle-fit method at a frequency of about 19.6 GHz and temperatures of 30 K to 90 K, which is compared with the measured values by using the Lorentzian-fit method. Good agreements are found between the two sets of $Q_0$ values measured by using the two different methods whether the resonator is used in a weak-coupling scheme or a strong-coupling scheme, showing reliability of both methods fur measuring the resonator $Q_0$ accurately. The $Q_0$ of sapphire resonators with a gap between the top plate and the rest of the resonator is also discussed.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.443-461
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• 2009

In order to overcome the lack of Korean credit rating migration data, we consider an empirical Bayes procedure to estimate credit rating migration matrices. We derive the posterior probabilities of Korean credit rating transitions by utilizing the Moody's rating migration data and the credit rating assignments from Korean rating agency as prior information and likelihood, respectively. Metrics based upon the average transition probability are developed to characterize the migration matrices and compare our Bayesian migration matrices with some given matrices. Time series data for the metrics show that our Bayesian matrices are stable, while the matrices based on Korean data have large variation in time. The bootstrap tests demonstrate that the results from the three estimation methods are significantly different and the Bayesian matrices are more affected by Korean data than the Moody's data. Finally, Monte Carlo simulations for computing the values of a portfolio and its credit VaRs are performed to compare these migration matrices.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.285-291
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• 2002

The shearing process for the sheet metal is normally used in the precision elements such as a frame of TFT-LCD or lead frame of If chips. In these precision elements, the burr formation prevents the system assembly and needs the additional burr removing process. In this paper, we developed the small size NC punching system which has an aligning kinematics between the rectangular shaped punch and die. The punch is driven by an ai cylinder and the sheet metal is moving on the X-Y table system which is driven by two stewing motors. The microprocessor control the whole system and communicate with the monitoring PC by RS232C serial communication protocol. The graphic user interface program in PC monitors nil control the punching system. The cross shaped joint hinge supports the punching die and positioned by two differential screws, whose are installed in perpendicular directions. The aligning between the punch and die is performed using the sheets of half thickness(0.1mm Brass) of the real process for the frame of the TFT-LCD. Using half thickness Brass, the burr formation is magnified and we can decide the aligning direction more easily then using the real thickness(0.2mm) Aluminum. In this paper, the aligning results are measured manually using the SEM photographs and we hope to make the automated aligning procedures using some kinds of image processing techniques.

• Childhood Kidney Diseases
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• v.22 no.2
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• pp.37-41
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• 2018

Purpose: Familial renal glucosuria (FRG, OMIM #233100) is a rare but relatively benign genetic condition characterized by persistent isolated glucosuria with a normal blood glucose level. We report three additional SLC5A2 mutations and examine their phenotypic and genetic characteristics in a Korean FRG cohort. We also reviewed the literature and summarized the genotypes of all Korean patients with FRG. Methods: A genetic analysis was conducted by directly sequencing all 14 exons of the SLC5A2 gene and their flanking regions in six unrelated Korean children with FRG and their family members. Novel non-synonymous single-nucleotide polymorphisms were identified and compared with known mutations that are repeatedly detected in the Korean population. Results: We found two novel mutations [c.274G>A (G92S) and c.1168C>T (L390F)] and one known [c.1382G>A (S461N)] mutation in each family and one recurrent mutation [c.1346G>A (G449D) (rs768392222)] in two pedigrees. The recurrent G449D was predicted to be "possibly damaging," with a score of 0.883 in Polyphen-2, while G92S, L390F, and S461N were predicted to be "probably damaging," with scores of 1.000, 0.999, and 0.996, respectively. Conclusions: Two novel, one previously reported, and one recurrent mutation were identified in six Korean FRG pedigrees as causative mutations of renal glucosuria. Sequence variations in the SLC5A2 gene were frequently detected in children with persistent isolated glucosuria. A long-term follow-up of this FRG cohort is needed to understand how these specific SGLT2 mutations impair kidney function and energy homeostasis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1C
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• pp.24-31
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• 2003

In this paper, a new opto-digital multiple information hiding and real-time extracting system is implemented. That is, multiple information is hidden in a cover image by using the stego keys which are generated by combined use of random sequence(RS) and Hadamard matrix(HM) and these hidden information is extracted in real-time by using a new optical correlator-based extraction system. In the experiment, 3 kinds of information, English alphabet of "N", "R", "L" having 512$\times$512 pixels, are formulated 8$\times$8 blocks and each of these information is multiplied with the corresponding stego keys having 64$\times$64 pixels one by one. And then, by adding these modulated data to a cover image of "Lena"having 512$\times$512 pixels, a stego image is finally generated. In this paper, as an extraction system, a new optical nonlinear joint transform correlator(NJTC) is introduced to extract the hidden data from a stego image in real-time, in which optical correlation between the stego image and each of the stego keys is performed and from these correlation outputs the hidden data can be asily exacted in real-time. Especially, it is found that the SNRs of the correlation outputs in the proposed optical NJTC-based extraction system has been improved to 7㏈ on average by comparison with those of the conventional JTC system under the condition of having a nonlinear parameter less than k=0.4. This good experimental results might suggest a possibility of implementation of an opto-digital multiple information hiding and real-time extracting system.

• Korean Journal of Remote Sensing
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• v.27 no.3
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• pp.315-328
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• 2011

Landsat data incorporated with additional bands-normalized difference vegetation index (NDVI) and band ratios were used to assess the extent and rate of deforestation in the Gunung Mutis Nature Reserve (GMNR), a mountainous tropical forest in Eastern of Indonesia. Hybrid classification was chosen as the classification approach. In this approach, the unsupervised classification-iterative self-organizing data analysis (ISODATA) was used to create signature files and training data set. A statistical separability measurement-transformed divergence (TD) was used to identify the combination of bands that showed the highest distinction between the land cover classes in training data set. Supervised classification-maximum likelihood classification (MLC) was performed using selected bands and the training data set. Post-classification smoothing and accuracy assessment were applied to classified image. Post-classification comparison was used to assess the extent of deforestation, of which the rate of deforestation was calculated by the formula suggested by Food Agriculture Organization (FAO). The results of two periods of deforestation assessment showed that the extent of deforestation during 1989-1999 was 720.72 ha, 0.80% of annual rate of deforestation, and its extent of deforestation during 1999-2009 was 1,059.12 ha, 1.31% of annual rate of deforestation. Such results are important for the GMNR authority to establish strategies, plans and actions for combating deforestation.

• Journal of Korea Water Resources Association
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• v.39 no.10 s.171
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• pp.845-854
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• 2006

Establishment of snowmelt factors is necessary to simulate stream flow using snowmelt models during snowmelt periods. The few observed data related snowmelt was the major cause of difficulty in extracting snowmelt factors such as snow cover area, snow depth and depletion curve. The objective of this study was to extract snowmelt factors using RS, GIS technique and meteorological data. Snow cover maps were derived from NOAA/AVHRR images for the winter seasons from 1997 to 2003. Distributed snow depth was mapped by overlapping between snow cover maps and interpolated snowfall maps from 69 meteorological observation station. Depletion curves of snowmelt area were described from the linear regression equations of each year between the average temperature and snow cover area in Soyanggang-dam and chungju-dam watershed.