• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.1
• /
• pp.79-87
• /
• 2013

A new modulation technique - correlative encoded FSK (CEFSK) - for use in power and bandwidth limited digital communication system is proposed. CEFSK is free of ISI and generates output signals which have a smooth and continuous phase transition and a reduced envelope fluctuation by keeping correlation between amplitude and phases of two subsequent symbols. In comparison to conventional one-bit differential detected (1DD) GFSK, the performance of the 1DD-CEFSK in a non-linearly amplified (NLA) channel impaired by additive white Gaussian noise (AWGN), ISI and IM, is analyzed via computer simulation. The simulation result shows that, in an NLA single-channel, 1DD-CEFSK provides a signal-to-noise ratio (SNR) advantage of up to 1.2dB and 0.8dB at BER of $1{\times}10^{-4}$ when input back-off (IBO) of HPA is -1.0dB and -3.0dB, respectively. For the same channel environment with multi-channel, 1DD-CEFSK outperforms 1DD-GFSK by 1.1dB in SNR, regardless of the value of IBO.

• Korean Journal of Agricultural Science
• /
• v.16 no.2
• /
• pp.163-168
• /
• 1989

Fourty-four isolates showed acetylene-reducing(nitrogenase)activity under the atmosphere of 89% Ar, 10% $C_2H_2$ and 1 % $O_{2{\cdot}}$, these nitrogen-fixing isolates characterized chemotaxonomically and their taxonomic status was disscussed; twenty-three isolates corresponded to Azospirillum. They were curved/spiral rods, gram negative, motile by a polar flagellum, and also utilized glucose in nitrogen free medild by a polar flagellum, and also utilized glucose in nitrogen free medium. but the cellular fatty acid composition and quinone system of these isolates showed quite different characteristics with reference strains. Therefore, the taxonomic status of this nitrogen-fixing bacteria is disscussed and a new species Azospirillum. Sixty forur isolates utilized C-l compounds such as methanol and formic acid. phenotypic and chemotaxonomic characteristics of methanol utilizing isolates were investigated and their taxonomic status was discussed; Twenty-one isolates corresponded to Hyphomicrobium and for the other regular rods and irregular rods utilizing isolates showed different cellular fatty acid composition. These isolates were grouped into 8 cluster analysis and similarity values based on correlation coefficients. Among these 8 clusters, two corresponded Pseudomonas and for the other were not decided.

• Korean Journal of Agricultural Science
• /
• v.16 no.2
• /
• pp.152-162
• /
• 1989

Oligotrophic bacteria studied in the present report were isolated on a 100-fold dilution of the nutrient broth(NB) medium and were able to grow on a 10,000-fold dilution of the NB medium. Oligotrophbic bacteria were shown to exist abundantly in all layers of a rendzina forest soil through the year. Two-hundred three oligotrophic bacteria were isolated from forest soil at different layers(L.F.H and A layers), and their morphological and physiological characteristics were examined. They were divided into 4 groups on their cell shape: (1) regular rods(Group I. 73 isolates), (2) curved/spiral rods (Group II, 29 isolates), (3) irregular rods (Group III, 56 isolateds), (4) append aged organisms (Group IV, 45 isolates), A high propoltion(95%)of the isolated oligotrophs were Gram-negative. all the isolated were aerobic, nonspore-formers. Forty isolates utilized fenolic acid such as ferulic acid or p-coumaric acid. sixty-for isolateds utilized C-1 compounds such as methanol or formic acid.

• Sijohaknonchong
• /
• v.22
• /
• pp.5-25
• /
• 2005

The purpose of this study is to show Da-seuck(다석) and his Sip those were never introduced to the academic world of Korean literature yet. Daseuck who kept company with Yook-dang(육당) and Chun-won(춘원) was a great philosopher of religion. He had ranged over world wide philosophy and founded his own angle of view to God. He had written diary in which many Sijo Poems more than 2,200 were written for 20 years from 1955 to 1974. The special features of his Sijo and the historical meanings are: First, Daseuck had written the most numerous Sijo Poems in number. Second, one of the special features of his Sijo is that most of his Sijo Poems contains his own ideas of God that is caused by his religious belief and his angle of view to Sijo. Third, his poetic words are too difficult to understand because he had used Korean old language that he understand them peculiarly.

• Journal of radiological science and technology
• /
• v.8 no.2
• /
• pp.3-9
• /
• 1985

From the study on the chest radiologic equipments and situations of university hospitals, general hospitals, and radiologic clinics located in Seoul area and Choong-cheong province, the author got conclusions as follows : 1. The rectfication methods of the equipments were employing mainly single or three-phase full wave, and 78% of the examined were using single phase full wave. 2. The focal sizes in case of small focus were less than 1.0mm in chest-only use, and more than 1.0mm in 81% of combined use. The focal sizes in case of large focus were more than 1.6mm in 78% of the total. 3. Maximum ratings of x-ray tubes were 47% at 125 kVp maximum tube voltage and 41% at 150kVp. The maximum tube currentes higher than 500mA were shown in 72% of all the examined. And the maximum exposure time was the range of 5-8sec. 4. Grid was not used in the 66% of all the hospitals. Equipment for chest-only was employing 10:1 grid ratio and the 2.0-2.9mmAl of total filtration formed 38% of all the examined. 5. In the processing time of exposed film, 68% of all was 90sec, and only 20% of all the examined used optimum developing temperature according to this condition. 6. In the radiographic conditions, more than 50% used low tube voltages lower than 70 kVp and only 3% of all the equipments used high tube voltages higher than 100 kVp. The 46.9% of all the equipments 300mA, and 53% of all used shorter exposure time less than 1/20(0.05) sec. 7. In the monthly average number of radiographs, 44% of all was x-ray the radiographs.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.1
• /
• pp.628-633
• /
• 2020

This paper presents an analysis of the shelf-life management program of the long-term storage one-shot system. The one-shot system is mainly maintained with long-term storage or non-operating status and is operated once at execution of the mission. The function corresponding to one-shot is mainly operated through a shelf-life item such as an explosive. The performance and characteristics of shelf-life item are subject to change as the storage period passes. Therefore, shelf-life management for maintaining good condition is very important during long-term storage, and criteria for management is necessary. We present a method for optimizing shelf-life extension by comparing criteria for management with current reliability. Next, the shelf-life evaluation schedule was decided by utilizing the reliability function of exponential distribution and Weibull distribution. Continuously accumulated test data from the shelf-life evaluation were analyzed, and the parameter of distribution was updated. The extension or expiration of shelf-life was selected by monitoring changes in reliability. In addition, we confirmed the applicability of the presented shelf-life management program by applying ASRP test data of the one-shot system K000 fuse.

• The Korean Journal of Mycology
• /
• v.19 no.4
• /
• pp.285-291
• /
• 1991

Sulfur dioxide discharged from the factories in Yeochun industrial complex severely damaged to the growth of oyster mushrooms. The continuous monitoring indicated that high concentration of sulfur dioxide was repeatedly detected in Kwang-Yang and Seung-Ju. The first injury symptoms on the mushroom fruit bodies were observed a day later when sulfur dioxide was detected over 300 ppb. Under the high concentration of sulfur dioxide exposure, the young fruit bodies showed blight and sudden death and the mature fruit bodies turned to blue-brown and frequently progressed to blight. The symptoms at Spring cropping were more severe than those at Autumn cropping. The severity was associated with the frequency of sulfur dioxide monitored. However, sulfur content in the mushroom fruit bodies and culture media did not show clear differences between the injured mushroom from Yeochun industrial complex areas and normal ones from no damaged areas.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.8
• /
• pp.2196-2203
• /
• 1999

This paper describes the bus scheduling problem and register optimization method in datapath synthesis. Scheduling is process of operation allocation to control steps in order to minimize the cost function under the given circumstances. For that purpose, we propose some formulations to minimize the cost function for bus assignment to get an optimal and minimal cost function in hardware allocations. Especially, bus and register minimization technique are fully considered which are the essential topics in hardware allocation. Register scheduling is done after the operation and bus scheduling. Experiments are done with the DFG model of fifth-order digital ware filter to show its effectiveness. Structural integer programming formulations are used to solve the scheduling problems in order to get the optimal scheduling results in the integer linear programming environment.

• Korean Journal of Digital Imaging in Medicine
• /
• v.12 no.2
• /
• pp.127-132
• /
• 2010

In this study, the correlation among the changes of Modulation Transfer Function(MTF) in the noise and high-contrast resolution and the change of Contrast to noise ratio(CNR) in the low-contrast resolution will be examined to investigate the estimation of image quality according to the type of algorithms. The image data obtained by scanning American Association of Physicists in Medicine(AAPM) phantom was applied to each algorithm and the exposure condition of 120 kVp, 250 mAs, and then the CT number and noise were measured. The MTF curved line of the high-contrast resolution was calculated with Point Spread Function(PSF) by using the analysis program by Philips, resulting in 0.5 MTF, 0.1 MTF and 0.02 MTF respectively. The low-contrast resolution was calculated with CNR and the uniformity was measured to each algorithm. Since the measurement value for the uniformity of the equipment was below ${\pm}$ 5 HU, which is the criterion figure, it was found to belong to the normal range. As the algorithm got closer from soft to edge, the standard deviation of CT number increased, which indicates that the noise increased as well. As for MTF, 0.5 MTF, 0.1 MTF and 0.02 MTF were all sharp algorithms, and as the algorithm got closer from soft to edge, it was possible to distinguish more clearly with the naked eye. On the other hand, CNR gradually decreased, because the difference between the contrast hole CT number and the acrylic CT number was the same while the noise of hole increased.

• Korean Journal of Digital Imaging in Medicine
• /
• v.11 no.2
• /
• pp.101-107
• /
• 2009

With the recent development of diagnosis using radiation and increasing demand of the medical treatment, we need to minimize radiation exposure dose. So, This is the method which reduce patient dose by measuring surface dose of radiographic change factor and by comparing theoretical and actual dose, when we take an X-ray which is generally used. By changing the factor of kV, mAs, FSD, whose range is 60 to 120 kV, 20 to 100 mAs, 80 to 180 cm, we compared theoretical surface dose with actual surface dose calculated by the simple calculation program, Bit system, and NDD-M method As a result, when kV and mAs were higher, theoretical surface dose and actual surface dose were more increased. but the higher FSD was, the more decreased surface dose was. According to this, the error were measured about 0.1 to 0.2 mGy in low dose part and about 0.7 to 1.5 mGy in high dose part. Therefore, this shows that theoretical surface dose calculation method is more correct in low dose part than in high dose part. In conclusion, we will have to make constant efforts which can reduce patient and radiographer's exposure dose, studying methods which can predict patient's radiation exposure dose more exactly.