• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.1
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• pp.81-88
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• 2014

Accurate wind data is essential for predicting airborne spread of virus. OpenFOAM was used for computational fluid dynamics (CFD) simulation procedure which is under GNU GPL (General Public License). Using complex terrain, DEM (Digital Elevation Map) that was prepared from GIS information covering a research site is converted to a three dimensional surface mesh that is composed by quad and full hexahedral space meshes. Around this surface mesh, an extended computational domain volume was designed. Atmospheric flow boundary conditions were used at inlet and roughness height and was considered at terrain by using rough wall function. Two different wind conditions that was relatively stable during certain periods were compared in 3 different locations for validating the accuracy of the CFD computed solution. The result shows about 10 % of difference between the calculated result and measured data. This procedure can simulate a prediction of time-series data for airborne virus spread that can be used to make a web-based forecasting system of airborne virus spread.

• Transactions of Materials Processing
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• v.25 no.2
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• pp.102-108
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• 2016

The aim of the current study was to develop an advanced prediction model for the slab width spread during hot rough rolling. Rough rolling consists of both vertical rolling using a set of profiled edger rolls and horizontal rolling using a set of plain work rolls. FE-simulations were performed to investigate the influences of process variables such as initial slab width, initial thickness, sizing draft, edger roll draft and work roll draft on the final slab width variation. From a statistical analysis of the simulation results, an advanced model, which can predict the slab width spread during the edger rolling and horizontal rolling, was developed. The experimental hot rolling trials showed that the newly developed model provided fairly accurate predictions on the slab width spread during hot rough rolling process using a profiled edger rolls.

• Fire Science and Engineering
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• v.23 no.4
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• pp.104-111
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• 2009

To research about the fire spread in Korean apartment house, a full-scale fire test in a four-story apartment was executed. The fire started at the third floor, and originated from overheated cooking oil in the kitchen. The apartment included all combustibles in general house. Through measuring temperature, measuring the concentration of oxygen and observing, we investigated the fire spread inside the apartment house. As a result, we got the data of the time needed for the initiation of fire, the time for fire to spread into each area in the house, and the time required until flash-over was seen. Also we grasped the understanding of the fire spread to the upper floor.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.404-409
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• 2014

This paper presents a Spread Spectrum Clock Generator (SSCG) based on Relaxation oscillator using Up/Down Counter. The current is controlled by a counter and the spread spectrum of the Relaxation Oscillator. A Relaxation Oscillator with temperature compensation using the BGR and ADC is presented. The current to determine the frequency of the Relaxation Oscillator can be controlled. The output frequency of the temperature can be compensated by adjusting the current according to the temperature using the code that is the output from the ADC and BGR. EMI Reduction of SSCG is 11 dB, and Spread down frequency is 150 kHz. The current consumption is $600{\mu}A$ from 5V and the operating frequency is from 2.3 MHz to 5.75 MHz. The rate of change of the output frequency with temperature was approximately ${\pm}1%$. The SSCG is fabricated in a 0.35um CMOS process with active area $250um{\times}440um$.

• Biomedical Science Letters
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• v.7 no.3
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• pp.139-143
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• 2001

The present study was conducted to determine whether skin spread of Myrrha has an effect on the cell regeneration as well as wound healing following dermal scald burn injury, keratinocyte growth factor (KGF) level was analyzed immunologically in conjunction with the histological changes occurred in skin tissue. The KGF contents in Myrrha skin spread group, which shows cell regeneration ability in skin tissue after burn, increased after 5 hours. After 24 hours, 'the content of Myrrha skin spread group is noticeably higher than at 5 hours postburn. After 72 hours, KGF was decreased compared to at 24 hours postburn. Acceleration effect of KGF production in Myrrha skin spread group was high. Together with the result of histological changes, skin spread of Myrrha reduced protein degeneration and edema in dermis, and induced proliferation of epithelial cells. The data suggest that Myrrha has accelerate cell regeneration and wound healing in case of scald burn skin by spreading of paste.

• Journal of Korean Society for Quality Management
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• v.41 no.1
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• pp.1-14
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• 2013

Purpose: The purpose of this research was to investigate the spread pattern of Korean legal certification systems and their impact on industry performance. Methods: It first analyzes the life cycle of legal certification systems and classifies them into four categories based on the spread patterns in a chronological view. A survey study is then conducted to find out the impact of legal certification systems on financial performance. Both the legal mandatory certification systems and the legal voluntary certification systems are included in the survey. Results: Four spread patterns of legal certification systems are sustainable growth, stagnation after growth, decrease after growth, and repetition of growth and declination. 56% of 293 certified corporations responded positively about the financial impact of their certification systems. Conclusion: The policy makers can utilize the results of this study in designing additional certification systems as well as promoting the current legal certification systems.

• Journal of Communications and Networks
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• v.15 no.3
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• pp.276-282
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• 2013

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading code from a random information source, rather than using the traditional pseudo-random noise (PN) codes. In this paper, we present our study of the SESS system performance under pulsed-noise jamming and show that iterative detection can significantly improve the bit error rate (BER) performance. The jamming performance of the SESS with correlation detection is verified to be similar to that of the conventional direct sequence spread spectrum (DSSS) system. On the other hand, the time diversity detection of the SESS can completely mitigate the effect of jamming by exploiting the inherent temporal diversity of the SESS system. Furthermore, iterative detection with multiple iterations can not only eliminate the jamming completely but also achieve a gain of approximately 1 dB at $10^{-3}$ BER as compared with the binary phase shift keying (BPSK) system under additive white gaussian noise (AWGN) by effectively combining the correlation and time diversity detections.

• The Korean Journal of Pain
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• v.2 no.1
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• pp.36-41
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• 1989

Splanchnic nerve block is performed to relieve intractable upper abdominal pain caused by carcinoma of the pancreas, stomach, liver, or colon; and upper abdominal metastasis of tumors having more distant origins. We have performed splanchnic nerve blocks under control of X-ray fluoroscopy, for all cases of alcohol splanchnic nerve block at $L_1$ vertebra, to determine both the position of the needle tips and the spread of contrast media. During the period from December 1987 to August 1988, this method was used in 40 cases of malignancy at Severance Hospital and we clinically evaluated the location of the needle tip and the spread of contrast media. The results were as follows: 1) Our method was a retrocrural approach, the splanchnic nerve block, in all cases. 2) Most of the inserted needle points were located in the upper and anterolateral part of the $L_1$ vertebra on the antero posterior roentagenogram and in the upper quarter anteriorly on the lateral roentgenogram. 3) There was no specific relationship between the location of the needle and the spread of the contrast media. 4) The contrast media was spread around the needle and then upward along the anterior margin of the vertebral body in most of the cases. 5) Pain relief was obtained immediately in 37 cases (92.5%), but in 3 cases only after a second splanchnic nerve block.

• The Journal of the Korea Contents Association
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• v.7 no.3
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• pp.42-49
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• 2007

This paper implements RFID(radio-frequency identification)System to which the system was apply SS(Spread Spectrum) method. The system designed by using the algorithm for microprocessor with PLL of the receiver, PN spread, modulation and demodulation of the transceiver, and transistor amplifier for the output of stabilized BPSK (Binary Phase Shift Keying) signal. furthermore, it reduced the interference of the signal by designing the micro-strip narrow banded patch antenna, which is convenient for printing and producing, and decreased the volume of filter size in the system. It is also designed for the lower powered system with the possible application to UHF band of $860\sim930MHz$ for the international standard frequency band, which is the quota share of RFID distribution system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.315-317
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• 2013

To analyze vertical fire spreadability of aluminum composite panel, real scale test of aluminum composite panel and fire retardant aluminum composite panel was conducted as well as analysis of domestic code, test and domestic reaserch resulted in following conclusion. Fire spread risk assessment of aluminum Composite Panel is impossible with the current regulations (Cone Calorimeter Test). It need to changes of regulatory and combustion expanded risk assessment and regulatory changes in the test methods need to be judged. Also, there is quite a big different between the general aluminum Composite Panel and semi-non combustible of aluminum Composite Panel. However it is also deemed to be danger when present in the sidewall to the top consisting of fire spread. From now on, it is needed the study about interpretation of fire spread and sidewall of vertical fire spread analysis not only experiments for aluminum Composite Panel.