• Journal of KIISE:Computing Practices and Letters
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• v.15 no.6
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• pp.425-429
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• 2009

Recently, Chen et al.'s proposed mutual authentication scheme based on the quadratic resiidue, finding the squaring root problem, for avoiding exhaustive search on the server. But, if a malicious reader sends same random value, the tag is traced by an adversary. Moreover, there is realization problem because of its limited ability to compute squaring and hash function. In this paper, we analyze Chen et al.'s scheme and its weakness. Furthermore we present an improved mutual authentication scheme based on the quadratic residue which solves the tracing problem by generating random value on the tag and uses only squaring. We also make the scheme satisfy to forward secrecy without updating and synchronizing and avoid exhaustive search.

• Journal of Astronomy and Space Sciences
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• v.30 no.1
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• pp.49-58
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• 2013

ARGO-M is a satellite laser ranging (SLR) system developed by the Korea Astronomy and Space Science Institute with the consideration of mobility and daytime and nighttime satellite observation. The ARGO-M optical system consists of 40 cm receiving telescope, 10 cm transmitting telescope, and detecting optics. For the development of ARGO-M optical system, the structural analysis was performed with regard to the optics and optomechanics design and the optical components. To ensure the optical performance, the quality was tested at the level of parts using the laser interferometer and ultra-high-precision measuring instruments. The assembly and alignment of ARGO-M optical system were conducted at an auto-collimation facility. As the transmission and reception are separated in the ARGO-M optical system, the pointing alignment between the transmitting telescope and receiving telescope is critical for precise target pointing. Thus, the alignment using the ground target and the radiant point observation of transmitting laser beam was carried out, and the lines of sight for the two telescopes were aligned within the required pointing precision. This paper describes the design, structural analysis, manufacture and assembly of parts, and entire process related with the alignment for the ARGO-M optical system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.258-264
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• 2012

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it is possible to derive the coupling loss factor which represents characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way (uni-directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two-stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure.

• Journal of Biosystems Engineering
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• v.36 no.3
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• pp.211-216
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• 2011

According to the result of the first report and the second report of this study, it was expected that soil heating in a protected cultivation in winter season would affect the initial growth and development of fruit. Based on the result of previous study, we compared height, leaf number, leaf area, fruit weight, crop growth rate (CGR), features and quantity of cucumber for 3 months after planting between the soil heating group and the non-heating group. The result were summarized as follows: The height, leaf number, leaf area and fruit weight of cucumber in the soil heating group were 12.5%, 14.6%, 21.4% and 22.8% higher, respectively, compared to those of cucumber in the non-heating group. Although both the soil heating group and the non-heating group similarly showed an increasing pattern in CGR after transplanting, the soil heating group showed the increased CGR by 12.1% compared to that of the non-heating group. The quantity of cucumber in the soil heating group was about 26% higher than that of the non-heating group. It is assumed that the activation of initial growth and development of fruit in the heating group resulted in the increase of quantity.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.267-270
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• 2009

Naringenin is a bioactive flavanone containing antioxidative, anti-inflammatory, and anticarcinogenic properties. The inhibitory effects on hyaluronidase of naringenin and its novel derivatives were evaluated. Among these flavonoids at $200{\mu}M$ concentration, 7-O-butyl naringenin had the highest inhibitory effect on hyaluronidase with 44.84%. In addition, For naringenin at concentrations of 0, 150, and $190{\mu}M$, the apparent Michaelis constants ($_{app}K_m$) were calculated to be $0.60{\pm}0.02$, $0.43{\pm}0.02$, and $0.41{\pm}0.01\;mg/mL$ of substrate, respectively; for 7-O-butyl naringenin at 0, 20, and $30{\mu}M$ concentrations, those were $0.44{\pm}0.03$ and $0.27{\pm}0.03\;mg/mL$, respectively. The $V_{max}$ values at 150 and $190{\mu}M$ naringenin were $0.59{\pm}0.02$ and $0.56{\pm}0.01\;mg/mL/min$, respectively; and those at 20 and $30{\mu}M$ 7-O-butyl naringenin were $0.50{\pm}0.02$ and $0.33{\pm}0.02\;mg/mL/min$, respectively. However, the slopes of each inhibitory reaction were not significantly different. Therefore, naringenin and 7-O-butyl naringenin were shown to be uncompetitive inhibitors. These results demonstrate the potential use of 7-O-butyl naringenin as an anti-inflammatory substance.

• Food Science of Animal Resources
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• v.31 no.2
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• pp.311-315
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• 2011

The objective of this study was to evaluate the antimicrobial effects of various natural flavonoids against growth of psychotropic Bacillus cereus strains, which cause dairy food outbreaks. Flavonoids were first screened for their ability to inhibit growth of B. cereus strains using the paper-disc diffusion test. Second, the growth inhibitory effect of selected flavonoids was evaluated in tryptic soy broth supplemented with 0.6% yeast extract, and the bactericidal effect of the flavonoids was measured in 0.8% (w/v) NaCl solution. Based on the paper-disc diffusion test, kaempferol was effectively active against B. cereus P14 and B. cereus KCCM 40935. Kaempferol had an antimicrobial effect at concentrations greater than 100 ${\mu}M$, and the numbers of B. cereus P14 and B. cereus KCCM 40935 decreased by 3.55 and 1.5 log cycles, respectively. The cell numbers of B. cereus P14 and B. cereus KCCM 40935 treated with 50 ${\mu}M$ kaempferol were reduced by 4.18 and 2.84 log cycles during a 24 h incubation to test the bactericidal effect of kaempferol (p<0.05). The results indicate that kaempferol had the greatest antimicrobial effect among the psychotropic B. cereus strains and the natural flavonoids tested.

• Imaging Science in Dentistry
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• v.37 no.1
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• pp.15-18
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• 2007

Purpose : Disc and condylar position were observed on MRIs of temporomandibular joint disorder patients and condylar position agreement between MRI and tranascranal radiography was evaluated. Materials and Methods MRI and transcranial radiographs of both TM joints from 67 patients with temporemandibular disorder were used. On MRI, the position and shape of disc and condylar position as anterior, middle, posterior was evaluated at medial, center, and lateral views. On transcranial radiographs, condylar position was evaluated using the shortest distance from condyle to fossa in anterior, superior, and posterior directions. Results. 1. On MRI, 96 joints (71.6%) of 134 had anterior disc dispalcement with reduction and 38 joints (28.4%) without reduction. 2. Fourteen (14.6%) of 96 reducible joints showed anterior condylar position, 19 (19.8%) showed central position, 63 joints (65.6%) showed posterior position. Two joints (5.3%) of 38 non-reducible joints showed anterior condylar position, while 9 (23.7%) showed central position, and 27 (71.1%)-posterior position. 3. In 85 joints (63.4%) of 134, the transcranial condylar position agreed with that of the central MRI view, 10 joints (7.5%) with that of medial, 16 joints (11.9%) with that of lateral, and 23 joints (17.2%) disagreed with that of MRI. Conclusion : On MRT, most oi the reducible and non-reducible joints showed posterior condylar position. Transcranial radiographs taken with machine designed for TMJ had better agreement of condylar position with that of MRI. Extremely narrow joint spaces or very posterior condylar positions observed on transcranial radiographs had a little more than fifty percent agreement with those of MRIs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.487-497
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• 2008

This paper proposes a new adaptive QRD-M algorithm for MIMO systems. The proposed scheme controls the number of survivor paths,0 based on the channel condition at each layer. The original QRD-M algorithm used fixed M at each layer and it needs large M to achieve near-MLD (maximum-likelihood detection) performance. However, using the large M increases the computation complexity. In this paper, we further effectively control M by employing the channel indicator which includes not only the channel gain, but also instantaneous noise information without necessity of SNR measurement. We found that the ratio of the minimum path metric to the second minimum is good reliability indicator for the channel condition. By adaptively changing M based on this ratio, the proposed scheme effectively achieves near MLD performance and computation complexity of the proposed scheme is significantly smaller than the conventional QRD-M algorithms.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.89-96
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• 2005

This paper discusses the daytime atmospheric conditions and the possibility of daytime star detection with the purpose of practical use of the star sensor for daylight navigation. In order to estimate the daytime atmospheric data, we use the standard atmospheric model (LOWTRAN 7), from which atmospheric transmittance and radiance from background sky are calculated. Assuming the star sensor with an optical filter to reduce background radiation, different separation angles between the star sensor and the sun are set up to express the effect of the solar radiation. As considerations of field of view (FOV) of the star sensor, the variation of the sky background radiation and the star density of the detectable star are analyzed. In addition, the integration time to achieve a required signal-to-noise ratio and the number of the radiation-caused electrons of the charge coupled detector(CCD) working as the limit to daylight application of the star sensor are calculated.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.507-512
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• 2016

As the characteristics, attributes, and accepted way of media have been changing with newly emerging media, human recognition and the communication structure have also been changing. Media are not isolated from the others and emerge in the cultural context; With the drive to juxtapose the old and the new to be in diversified forms, the old media are utilized and improved. In this rapidly changing circumstance by the media, we attempt to theoretically explore the concept and characteristics of visual communication and the media related to augmented reality. Augmented reality does not create something out of nothing but renew the expression; Thus, it reforms the structure of communication. Therefore, there is a significance to look into theories of W.Benjamin, M.McLuhan, Norbert Bolz, and Jean Baudrillard who linked the past to the present in accordance with the new era of communication for us to find out the meaning of augmented reality in the current cultural context.