• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3983-3990
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• 2012

The hazardous effects of heavy alcohol intake and smoking to body systems have been identified by numerous studies, and there is many influencing factors on alcohol intake and smoking choices. The aim of this study is to identify the correlation between alcohol intake and digit ratio (2D:4D), as well as smoking and digit ratio (2D:4D) in university students. Participants were 121 male and 314 female university students. After filling in questionnaire related alcohol and smoking history, 2nd and 4th finger lengths were measured on both hands using vernier callipers with photocopy. This study showed 2D:4D of the males was 0.95, and that of the females was 0.96. There was a significant difference between male and female in digit ratio. The digit ratio according alcohol intake level significantly differed in only women's left hand. The digit ratio according smoking level significantly differed in only men's left hand. Moreover, The digit ratio was negatively associated with alcohol intake and smoking. The results of this study suggest that the digit ratio (2D:4D) affected with fetal testosterone concentration is negatively related to alcohol intake and smoking. Therefore, the digit ratio would be used in preventive program of alcohol intake and smoking of adolescent, or in antialcoholism /smoking cessation program as a biological basic data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.104-112
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• 2019

The material properties of the 3D printing cement composite mortar were evaluated, and the performance range in which printing was possible was calculated using the void ratio in a fresh state as a single index. As a results of the tests, as the water-binder ratio (W/B) increased, the mortar flow value increased and the density and strength decreased. As the sand-binder ratio (SS/B) increased, the mortar flow value decreased. However, strength and density increased and decreased up to a certain SS/B. As admixture-binder ratio (Ad/B) increased, mortar flow value, density, and strength decreased. These trends make it difficult to mix-design to meet the target performances of 3D printing mortars, represented by extrudability and buildability. The value of mortar flow increased proportionally with the void ratio, while the density and strength apparently decreased as the void ratio increased. This indicates that void ratio can be utilized as a single index for controlling the material properties in the design of mortar mixtures. It was found that mortar mixture could be printed by a 3D printer when the void ratio was in the range from 0.6 to 0.7. This was verified by printing a mortar which has the void ratio of 0.634. The mortar was produced with the mixture design of W/B 35.0%, SS/B 60.0%, and Ad/B 0.1%. Further research applying diverse admixtures is needed to improve the quality of 3D printing output mortars.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.2
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• pp.154-159
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• 2015

This paper deals with the effect of concrete target size on penetration of projectiles. We investigated the penetration depth and residual velocity of projectiles using the 2-D axial symmetric model. Most analysis were conducted with 13 kg projectile (striking velocity: 456.4 m/s) and concrete target with compressive strength of 39 MPa. This paper provided penetration depth (or residual velocity) versus ratio D/d (target diameter, D and projectile diameter, d). When the bottom of concrete cylinder was constrained, penetration depth converged to limit depth more than the ratio D/d of 36. The residual velocity of projectile with thin concrete target were investigated. The residual velocity was converged to specific velocity more than the ratio D/d of 16.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.1-14
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• 1996

Effects of the external optical feedback on the optical transmission characteristics were evaluated for 3 kinds of commercialized DFB-LD modules for 2.5Gbps optical communication systems. As a result, intensity noise induced by external optical feedback via generating the external cavity modes deteriorated the transmission performances of sthe DFB-LD modules as much as 1.5dB, 1.2dB, and 1.0dB for the maximum feedback ratio of -8.8dB which corresponds to the worst reflection along the fiber transmission line. Additional penalty of 0.5dB was occurrred when state of polarization of feedback light was adjusted. From the experiments evaluating the isolation ratio of the single polarization optical isolator, decrease of the polarization dependent isolation ratio as much as 10dB from that of specification and the effective isolation ratio as much as 20dB from that of specification was mjor cause of high sensitivity of DFB-LD modules to external feedback. It was suggested that polarization independent optical isolator or single polarization optical isolator with isolation ratio specification of more than 40dB is required for 2.5Gbps DFB-LD modules with complete suppression of external feedback effects.

• PNF and Movement
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• v.9 no.3
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• pp.19-24
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• 2011

Purpose : The purpose of this study was to analyze the effect of PNF lower extremity flexion pattern on the eletromyographic (EMG) activity in rectus abdominis, internal oblique abdominal, external oblique abdominal, erector spinae. Methods : Twenty-six healthy adults volunteered to participate in this study. Subjects were required complete following two PNF lower extremity patterns; flexion-adduction-external rotation with knee flexion (D1) and flexion-abduction-internal rotation with knee flexion (D2). A paired t-test was used to determine the influence of the PNF two patterns on muscle activity for each muscle and descriptive statistics was used to determine local/global muscle ratio. Results : The D1 pattern was showed significant rectus abdominis (p<.05) and Median of internal oblique/rectus abdominis ratio was 2.23 and internal oblique/external oblique ratio was 1.53. The D2 pattern showed significant erector spinae (p<.05) and Median of internal oblique/rectus abdominis ratio was 3.06 and internal oblique/external oblique ratio was 1.72. Conclusion : The D1 pattern made rectus abdominis activation increase. The D2 pattern made erector spinae activation increase. As compared D1 and D2 pattern on trunk muscle activation, it's will be useful decision making for the trunk muscle strength and stabilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.296-301
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• 2011

GPS(Global Positioning System) service is more important than other wireless services. The GPS is necessary protected from any other interference signals. Therefore, GPS protection ratio was calculated on the basis of bit error rate(BER) in this paper. Simulation results show that the allowable maximum interference power is -190 dBm/Hz and the ratio of interference to noise(I/N) is -16 dB. The achieved protection ratio is available to be applied as the protection criteria of GPS in considering the implementation margin of 4 dB. As a result, the proposed protection ratio of GPS is expected to give standard for a stable GPS service.

• Journal of Oriental Neuropsychiatry
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• v.28 no.3
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• pp.157-164
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• 2017

Objectives: The purpose of this study is the research of the 2D:4D ratio and its correlation with the Sasang constitution and the MBTI preference types. Methods: A measurement of the 2D:4D ratios of 101 South Korean medical students was performed, the QSCC-II and PSSC-2004 were used to diagnose the Sasang constitution, and MBTI testing was performed to classify the preference types. Results: In the relationship between the Sasang constitution and the 2D:4D ratios, a statistically significant difference is absent in the 2D:4D ratios of the group comprising both sexes in the order of Taeumin, Soyangin, and Soeumin. A statistically significant difference is also lacking in the 2D:4D ratios of the male-only group in the order of Taeumin, Soyangin, and Soeumin. The 2D:4D ratios are higher in the female group only, but again a statistically significant difference is absent. In the 2D:4D ratios according to the MBTI preference type, the 2D:4D ratios of the I, S, F, and P types are higher in the unisex group, but a significant difference is not evident. The 2D:4D ratios of the E, N, F, and P types are higher in the male-only group, but again a significant difference is not evident. In the female-only group, the mean of the 2D:4D ratios of the I, S, F, and P types is higher, but a significant difference is not identifiable. Conclusions: The Sasang constitution and the MBTI preference types did not show statistically significant differences regarding the 2D:4D ratios of the male, female, and unisex groups.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.55-61
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• 2011

In this paper, the outage probability of device-to-device (D2D) uplink communication underlaying cellular networks is analyzed over Rayleigh fading. We assume that a D2D pair and M cellular user equipments share the same frequency resources. To prevent any harmful interference from a D2D transmitter to the BS, the maximum transmit power of the D2D transmitter is strictly limited. Under these assumptions, the outage probability is represented as a function of the interference-to-signal ratio from M cellular user equipments to a D2D receiver and the number of cellular user equipments, M. In addition, the interference-to-signal ratio is represented as a function of distances among D2D equipments, cellular user equipments and the BS. Simulation results validate these analytical results.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.417-423
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• 2011

Purpose: This study was to investigate that near gradient AC/A ratio could be used to prescribe a patient with distance exophoria, we compared the difference between distance gradient AC/A ratio and near gradient AC/A ratio. Also, this thesis was to understand the relationship between calculated AC/A ratio and gradient AC/A ratio. Methods: Objective and subjective refractive error were corrected and we used Howell (3 m) chart for distance phoria tests and Howell-Kim (40 cm) chart for near phoria tests. The near gradient AC/A ratio and calculated AC/A ratio were used by Howell-Kim (40 cm) combined with +1.00 D, -1.00 D, +2.00 D and -2.00 D. Results: The average value of distance exophoria was 1.17${\pm}$1.17 $\Delta$, and the average value of near exophoria was 3.71${\pm}$2.80 $\Delta$ (t-test. p<0.001). The correlation of distance phoria with near phoria was little higher (r = 0.59, p < 0.001). Gradient AC/A ratios depending on measuring distance and stimulus were higher (r = 0.11~0.53. P < 0.001), when distance was shorter and stimulus to accommodation was more. Also, stimulus to accommodation by plus lens was higher than stimulus to accommodation by minus lens (paired t-test. p < 0.001). There was negative correlation between calculated AC/A ratio and gradient AC/A ratio. As the calculated AC/A ratio was higher, gradient AC/A ratio was lesser. Near gradient AC/A ratio was slightly higher than distance gradient AC/A ratio. Distance and near gradient AC/A ratio taken through the subjective -1.00 D were 1.30 $\Delta$/D and 1.68 $\Delta$/D(t-test. t=1.67, p < 0.001). Conclusions: There is negative correlation between calculated AC/A ratio and gradient AC/A ratio. Also, there is subtle difference between near gradient AC/A ratio and distance gradient AC/A ratio. Therefore, we need to measure distance gradient AC/A ratio when a practitioner prescribe glasses for a patient with distance exophoria.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.151-155
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• 2001

In order to obtain the fundamental data on the auditory thresholds of fishes for marine ranching, the auditory thresholds of black rockfish Sebastes inermis were measured in the presence of masking noise in the spectrum level range of $73\~83$ dB (0 dB re $1{\mu}Pa/\sqrt{Hz}$) with a classical cardiac conditioning technique. Critical ratios were about $28\~34$ dB at $80\~300$ Hz and $47\~52$ dB at $500\~800$ Hz. The ratio increased almost linearly with increasing frequency to 500 Hz. The noise spectrum level at the start of masking was about 70 dB within the frequency range of $80\~800$ Hz excepting 65 dB at 300 Hz. It means that hearing of the black rockfish is masked in the natural environment with the noise spectrum level above 65 dB. The sound pressure level of $200\~300$ Hz recognized by black rockfish was above 96 dB under the ambient noise and the critical ratio of them was above 26 dB.