• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.175-183
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• 2006

This letter proposes a Direct Sequence Spread Spectrum (DS-SS)-based Flight Termination System(FTS) and show the simulation results and implements the system using FRGAs. The DS-SS FTS has immunity interference signals and the influence of jamming signal. Moreover, a DS-SS FTS can provides effects on an authentication and encryption with spread codes. And the system uses more less power than an analog FM system. We used Reed-Solomon (32, 28) code and triple Data Encryption Standard(3DES) for error correction and data encryption. Also we used counter algorithm for unauthenticated device's attack The spread codes of In-phase channel and Quadrature channel were generated by Gold sequence generators. The system was implemented in Altera APEX20K100E FPGA for the ground system and EPF10K100ARC240-3 for the airborne system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.246-249
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• 2007

In numerical analysis for phase change material, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be used without modelling. In this study applicability of neural networks in modelling superheated vapor region of water was examined by comparing with the quadratic spline. neural network consists of an input layer with 2 nodes, two hidden layers and an output layer with 3 nodes. Quadratic spline interpoation method was also applied for comparison. Neural network model revealed smaller percentage error to quadratic spline interpolation. From these results, it is confirmed that the neural networks could be powerful method in modelling the superheated range of the steam table.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.144-150
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• 2020

This study examined the current status of ATE in the development stage of the domestic guided weapons field, including the re-establishment of automatic test equipment (ATE), and attempted to develop methods to verify the validity of ATE in the defense sector. This study includes methods for confirming the repeatability and reproducibility of newly manufactured or replaced ATE. An error injection test is required for validation in the development phase. And pre-inspection steps are required for validation. When developing ATE, the use of an international standard testing script language ensures efficient validation and SW reliability. This ensures interoperability between the main and test equipment, and the tester can secure a test system platform that supports standardized testing methods, which is considered to be effective in validating specific ATE for each weapon system.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.371-375
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• 2008

In blood pressure measurement, the oscillometric method detects and analyzes the pulse pressure oscillation while deflating the cuff around the arm. For its principle, one has to inflate cuff pressure above the subject's systolic pressure and deflate below the diastolic pressure. Most of the commercialized devices inflate until the fixed target pressure and deflate until the fixed completion pressure because there is no way to know the systolic and diastolic pressure before measurement. Too high target pressure makes stress to the subject and too low target pressure makes big error or long measurement time because of re-inflation. There are similar problems for inadequate completion pressure. In this study, we suggest new algorithm to set proper target and completion pressure for each subject by analyzing pressure waveform while inflating period. We compared our proposed method and auscultation method to see the errors of estimation. The differences between the two measurements were -4.02$\pm$4.80mmHg, -10.50$\pm$10.57mmHg and -0.78$\pm$5.l7mmHg for mean arterial pressure, systolic pressure and diastolic pressure respectively. Consequently, we could set the target pressure by 30 mmHg higher than our estimation and we could stop at 20mmHg lower than our estimated diastolic pressure. Using this method, we could reduce the measurement time.

• Radiation Oncology Journal
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• v.35 no.1
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• pp.65-70
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• 2017

Purpose: To evaluate the utility of implanted surgical clips for detecting interfractional errors in the treatment of hepatobiliary and pancreatic cancer with postoperative radiotherapy (PORT). Methods and Materials: Twenty patients had been treated with PORT for locally advanced hepatobiliary or pancreatic cancer, from November 2014 to April 2016. Patients underwent computed tomography simulation and were treated in expiratory breathing phase. During treatment, orthogonal kilovoltage (kV) imaging was taken twice a week, and isocenter shifts were made to match bony anatomy. The difference in position of clips between kV images and digitally reconstructed radiographs was determined. Clips were consist of 3 proximal clips (clip_p, ${\leq}2cm$) and 3 distal clips (clip_d, >2 cm), which were classified according to distance from treatment center. The interfractional displacements of clips were measured in the superior-inferior (SI), anterior-posterior (AP), and right-left (RL) directions. Results: The translocation of clip was well correlated with diaphragm movement in 90.4% (190/210) of all images. The clip position errors greater than 5 mm were observed in 26.0% in SI, 1.8% in AP, and 5.4% in RL directions, respectively. Moreover, the clip position errors greater than 10 mm were observed in 1.9% in SI, 0.2% in AP, and 0.2% in RL directions, despite respiratory control. Conclusion: Quantitative analysis of surgical clip displacement reflect respiratory motion, setup errors and postoperative change of intraabdominal organ position. Furthermore, position of clips is distinguished easily in verification images. The identification of the surgical clip position may lead to a significant improvement in the accuracy of upper abdominal radiation therapy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.202-213
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• 2004

In this paper, we propose a preamble structure and synchronization/channel estimation methods for OFDM-based multiple antenna WLAN systems that have 200Mbps transmit rate. With the proposed preamble structure, multiple antenna WLAN systems are backward-compatible with IEEE 802.11a systems which use the same 5㎓ band and synchronization performance is better than that of single antenna OFDM systems. For channel estimation, the preamble overhead is small and performance degradation by timing synchronization error that causes the critical problem of conventional comb-type multiple antenna channel estimation method also can be minimized by frequency domain phase recovery. Synchronizer and channel estimator for proposed preamble structure are implemented and verified using Verilog HDL. For the system with 4 transmit antennas and 4 receive antennas, about 150K gates are needed for synchronizer and 12K gates for channel estimator.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.105-113
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• 2009

The feature models are widely used to model the commonalities and variabilities among the products in the domain engineering phase of software product line developments. The findings and corrections of the errors or consistencies in the feature models are essential to the successful software product line engineering. The aids of the automated tools are needed to perform the validation of the feature models effectively. This paper describes the approach based on JESS rule-base system to validate the feature models and proposes the feature model validation tool using this approach. The tool of this paper validates the feature models in real-time when modeling the feature models. Then it provides the information on existence of errors and the explanations on causes of those errors, which allows the feature modeler to create the error-free feature models. This attempt to validate the feature model using the rule-based system is supposed to be the first time in this research field.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.231-238
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• 1984

Normal range has use mainly in the first phase of the diagnostic process, that is, to screen or to raise ideas about possible pathology. The traditional method of determining it is based on the probability paper or on the mean plus or minus two standard deviations. These methods are often turned out to be vague and impractical. The percentile method is adequate and flexible, though. The appropriate limit of lower and upper points should be chosen by considering medical aspects above all things and also the reliability of the range determined by the standard error. The results of normal range are interesting, strictly speaking, only for the hospital concerned. Differences exist between the normal ranges reported by various sources (Bezemer et al, 1983). It would be best to establish the normal range based on a population comparable to a group of individuals to whom the normal range is to serve as a norm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5381-5399
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• 2016

Currently, the quantize-and-forward (QF) scheme with high order modulation and quantization has rather high complexity and it is thus impractical, especially in multiple relay cooperative communications. To overcome these deficiencies, an improved low complex QF scheme is proposed by the combination of the low order binary phase shift keying (BPSK) modulation and the 1-bit and 2-bit quantization, respectively. In this scheme, the relay selection is optimized by the best relay position for best bit-error-rate (BER) performance, where the relays are located closely to the destination node. In addition, an optimal power allocation is also suggested on a total power constraint. Finally, the BER and the achievable rate of the low order 1-bit, 2-bit and 3-bit QF schemes are simulated and analyzed. Simulation results indicate that the 3-bit QF scheme has about 1.8~5 dB, 4.5~7.5 dB and 1~2.5 dB performance gains than those of the decode-and-forward (DF), the 1-bit and 2-bit QF schemes, at BER of $10^{-2}$, respectively. For the 2-bit QF, the scheme of the normalized Source-Relay (S-R) distance with 0.9 has about 5dB, 7.5dB, 9dB and 15dB gains than those of the distance with 0.7, 0.5, 0.3 and 0.1, respectively, at BER of $10^{-3}$. In addition, the proposed optimal power allocation saves about 2.5dB much more relay power on an average than that of the fixed power allocation. Therefore, the proposed QF scheme can obtain excellent features, such as good BER performance, low complexity and high power efficiency, which make it much pragmatic in the future cooperative communications.

• Atmosphere
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• v.28 no.3
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• pp.233-245
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• 2018

This study explores the Subseasonal-to-Seasonal (S2S) prediction skills of the Northern Hemisphere mid-latitude geopotential height in the Global Seasonal forecasting model version 5 (GloSea5) hindcast experiment. The prediction skills are quantitatively verified for the period of 1991~2010 by computing the Anomaly Correlation Coefficient (ACC) and Mean Square Skill Score (MSSS). GloSea5 model shows a higher prediction skill in winter than in summer at most levels regardless of verification methods. Quantitatively, the prediction limit diagnosed with ACC skill of 500 hPa geopotential height, averaged over $30^{\circ}N{\sim}90^{\circ}N$, is 11.0 days in winter, but only 9.1 days in summer. These prediction limits are primarily set by the planetary-scale eddy phase errors. The stratospheric prediction skills are typically higher than the tropospheric skills except in the summer upper-stratosphere where prediction skills are substantially lower than upper-troposphere. The lack of the summer upper-stratospheric prediction skill is caused by zonal mean error, perhaps strongly related to model mean bias in the stratosphere.