• Korean Security Journal
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• no.53
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• pp.83-105
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• 2017

The purpose of this study is to identify the problems of In-Flight Security Officer responsible for the security of the aircraft in the situation where Acts of Unlawful Interference in Aircraft shows an increasing tendency and the aircraft security is threatened by the terror threat of IS(Daesh) and to suggests its policy implications. Based on the problems of In-Flight Security Officer system found in the media reports and laws, the US Air Marshal system and the domestic similar system were presented to the In-Flight Security Officer developmental implications. First, it is necessary to revise the "Operational Guidelines for Airline Operators' In-Flight security officer" and the related qualifications to the "National Technical Qualifications" system. Second, the plan to change the national civil servants of In-Flight Security Officer in the aircraft, Third, it is a plan to use the registered security guard system in the aircraft. Although this study has limitations the accessibility of information related to aviation security. But, contributions of this study is that the government's efforts to create the public sector jobs, the "strengthening of public services in the country", "the establishment of national accountability for safety accident prevention and disaster safety management" in the "A five-year plan for Government Operation" that it has a timeliness in that it is together. In addition, since there are not many researches related to In-Flight Security Officer, this study also has another contribution as a basic study of the researchers in the aviation security aircraft in the future.

• Korean Security Journal
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• no.53
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• pp.283-303
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• 2017

This study which was started to identify the factors that change the security level of military organizations, analyzed the data collected from articles written by the active officers in the Defense Daily Journal hoping to improve the military security level by the qualitative research method called Grounded Theory, and establish causal relationship how organizational members respond to insider security threats. As a result of the analysis, the causal condition is 'the security threat of the insider', the contextual condition is 'the specificity of the military organization', the central phenomenon is 'the conflict of values as a soldier', the arbitrary condition is 'the security consciousness', Strategy is 'the responds to security threats', and the result was 'security level change'. The core categories can be presented as 'the degree of conflict of values on insider security threats' and two hypotheses have been derived. First, the members of the military organization strongly felt the conflict of values about security threat as the tendency to emphasize security was strong, and they helped to develop the security level of organization by responding strongly. Second, the stronger the tendency to focus on colleagues, respond weakly to security threats. And it undermines the security level of the organization. Finally, in order to improve the security level of the organization, it is necessary to establish a solid security consciousness and to make institutional development to support it.

• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.25-35
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• 2013

This study examined 24 right-handed amateur baseball players. Twelve who had played baseball for more than 6 years were grouped as skilled players, while 12 who had played for 1-3 years were the unskilled player group. The swing motion was divided into four event phases: stance, backswing, impact, and follow-through. The mean and maximum plantar pressure, center of pressure, and ground reaction force were measured during each event phase. The mean and standard deviations for each variables were calculated and differences were validated with the independent sample t-test. A p-value <0.05 was considered statistically significant. The results were as follows. 1)The ideal stance is a stable, balanced position with more than 65% of weight on the right foot. There was significant difference in mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significant. 2)The effective backswing of a skilled player is comprised a rightward shift in weight to build maximum energy. More than 90% of the weight was on the right foot. There was a significant difference in the mean left plantar pressure, while the maximal plantar pressure and mean right plantar pressure did not differ significantly. 3) For an effective impact, a rapid shift in weight to the left foot is essential, so that a power hit is obtained. Significant difference in the mean and maximum plantar pressures of both feet were observed. 4)Follow-through requires wight balance, more on the right than the left, without leaning leftward. There was no significant difference in the mean or maximum plantar pressure. 5)The center of plantar pressure should move from the center of the foot to the toe. 6)The analyses of the ground reaction force suggest that a good swing involves a gradual shift in weight to the right side and a rapid leftward shift at impact. Good balance, with the center of gravity on the right side at follow-through, is also required.

• Elastomers and Composites
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• v.48 no.3
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• pp.216-220
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• 2013

The phase separation in Wood Flour-Polymer Composite (WPC) was investigated and the reasons for change in mechanical properties with the content of wood flour were explored. The wood flour-polypropylene composite samples with different wood flour contents were prepared. From differential scanning calorimetry (DSC) thermograms of WPC samples, the trend of crystallinity and melting temperature ($T_m$) were analyzed. The crystallinity and melting temperature increased and then decreased as the content of wood flour increased. From these results, it was confirmed that at the low wood flour content the wood flours were dispersed into the polypropylene matrix but at the high wood flour content, the phase separation between polymer and wood flour phases appeared. The tensile strength of WPC samples was continuously decreased with the increase of wood flour content. At a low wood flour content, the low interfacial bonding and the decrease in crystallinity were the main reasons for the decrease in tensile strength with the increase of wood flour content. At a high wood flour content, the decrease in tensile strength resulted from the interfacial defects between the polymer and wood flour phases. The impact strength of the WPC sample showed the maximum behavior with the content of wood flour. At a low wood flour content, the impact strength was enhanced owing to the decrease in brittleness, which results from the decrease in crystallinity. At a high wood flour content, however, the impact strength decreased due to phase separation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.100-102
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• 2013

Magnetron-sputtering법을 사용하여 기존에 연구하였던 CrAlN (Cr 7：Al 3)박막에 Si를 첨가하여 Si의 함량 변화에 따라 미세구조와 화학적 결합상태, 온도저항계수(TCR) 및 산화저항의 영향과 기계적특성 개선을 통한 multi-functional heater resistor layer로써의 가능성을 연구하였다. CrAlSiN 박막의 Si 함량에 변화에 따라 온도저항계수 변화를 확인하였으며 X-선 회절 분석(XRD) 패턴 분석결과 CrAlSiN 박막의 결정구조가 Bl-NaCl 구조를 가지고 있는 것을 확인하였으며 SEM과 AFM을 통한 표면 및 미세구조 분석결과 Si의 함량이 증가할수록 입자가 조밀해짐을 알 수 있었다. 최근 digital priting technology의 핵심 기술로 부각되고 있는 inkjet priting technology는 널리 태양전지뿐만 아니라 thin film process, lithography와 같은 반도체 공정 기술에 활용 할 수 있기 때문에 반도체 제조장비에도 사용되고 있으며, 현재 thermal inkjet 방식을 사용하고 있다. Inkjet printing technology는 전기 에너지를 잉크를 배출하기 위해 열에너지로 변환하는 thermal inkjet 방식을 사용하고 있는데, 이러한 thermal inkjet 방식은 기본적으로 전기저항이 필요하지만 electrical resistor layer는 잉크를 높은 온도에서 순간적으로 가열하기 때문에 부식이나 산화 등의 문제가 발생할 수 있어 이에 대한 보호층을 필요로 한다. 하지만, 고해상도, 고속 잉크젯 프린터, 대형 인쇄 등을 요구되고 있어 저 전력 중심의 잉크젯 프린터의 열효율을 방해하는 보호층 제거에 필요성이 제기되고 있다. 본 연구는 magnetron-sputtering을 사용하여 기존의 CrAlN 박막에 Si를 합성하여 anti-oxidation, corrosion resistance 그리고 low temperature coefficient of resistance 값을 갖는 multi-functional heater resistor layer로써 CrAlSiN 박막의 Si 함량에 따른 효과에 초점을 두었다. 본 실험은 CrAlN 박막에 Si 함량을 4~11 at%까지 첨가시켜 함량의 변화에 따른 특성변화를 확인하였다. 함량이 증가할수록 amorphous silicon nitride phase의 영향으로 박막의 roughness는 감소하였으며 XRD 분석결과 (111) peak의 Intensity가 감소함을 확인하였으며 SEM 관찰시 모든 박막이 columnar structure를 나타내었으며 Si함량이 증가할수록 입자가 치밀해짐을 보여주었다.Si함량이 증가할수록 CrAlN 박막에 비하여 면저항은 증가하였으며 TCR 측정결과 Si함량이 6.5 at%일 때 가장 안정한 TCR값을 나타내었다. Multi-functional heater resistor layer 역할을 하기 위해서, CrAlSiN 박막의 원소 분포, 표면 거칠기, 미세조직, 전기적 특성 등을 조사하였다. CrAlN 박막의 Si의 첨가는 크게 XRD 분석결과 주상 성장을 억제 할 수 있으며 SEM 분석을 통하여 Si 함량이 증가할수록 Si3N4 형성이 감소하며 입자크기가 작아짐을 확인하였다. 면저항의 경우 Si 함량이 증가함에 따라 높은 면저항을 나타내었으며 Si함량이 6.5 at%일 때 가장 낮은 TCR 값인 3120.53 ppm/K값을 보였다. 이 값은 상용되고 있는 heater resistor보다 높지만, CrAlSiN 박막이 더 우수한 기계적 특성을 가지고 있기 때문에 hybrid heater resistor로 적용할 수 있을 것으로 기대된다.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.65-73
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• 2016

The aim of this study was to investigate the UV-resistance of radiation-resistant bacteria isolated from the water of Han River, South Korea. The water sample was irradiated with 3 kGy gamma radiation prior to isolation. Radiation-resistant bacterial strains were isolated by standard serial dilution method on R2A and 1/10 diluted R2A agar. The resulting purely isolated 60 cultures of bacteria were analysed for UV resistance and used in further studies. Based on the comparative analyses of 16S rRNA gene sequences, the bacterial isolates were divided into 3 phyla (4 genera): the phylum Deinococcus-Thermus (the genus Deinococcus) was 61.7%, Bacteroidetes (Hymenobacter and Spirosoma) was 23.4%, and Firmicutes (Exiguobacterium) was 15%. The results suggested that twenty-nine isolates are candidates new species belonging to Deinococcus, Hymenobacter, and Spirosoma, or other new genera. Nine bacterial strains were selected among the novel candidates and the UV-resistance analysis was conducted. All the candidate bacterial strains showed high UV resistance, similar to that of D. radiodurans R1.

• Food Science of Animal Resources
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• v.22 no.3
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• pp.259-266
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• 2002

The egg shell membrane degrading isolated from soil was identified as Bacillus licheniformis by 16S rDNA identification method. A keratinase was isolated from the Baciilu licheniformis culture. DEAE-cellulose ion-exchange and Sephadex C-75 gel chromatograhies were used to purify the enzyme. The specific activity was increased 17.3-fold by the purification procedures. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and Sephadex G-75 chromatography indicated that the purified keratinase was monomeric and had a molecular weight of 65 kDa. The enzyme showed optimum activity at pH 9.0, and was stable above pH 9.0. The optimum temperature was 50$\^{C}$ and the enzyme was stable in the temperature ranges from 20$\^{C}$ to 50t. By the addition of 1 mM and 10 mM FeSO4, the activities of the enzyme were increased to 111$\pm$4.6% and 133$\pm$3.79%, respectively. The keratinase was an alkaline serine pretense because it was inhibited only by phenylmethylsulfonylfluorice (PMSF).

• Food Science of Animal Resources
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• v.22 no.3
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• pp.218-221
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• 2002

A total of 40 domestic-fed imported beef cattle were used to determine meat quality traits. Sirloin was taken from each 10 of Hereford, Angus, Hurray Grey(MG), Cross breed(Hereford$\times$Angus) and objective and subjective meat quality were assessed after a 7 days ageing(0$\pm$1$\^{C}$). Results showed that ultimate pH and fat hardness was not affected by breeds. MG showed a higher water holding capacity and consequently a lower cooking loss(%) than the other breeds(p<0.05). Angus sirloin was shown to be the toughest meat(assessed by WB-shear force), Hereford and MG resulted in the most tender meat(p<0.05). Objective meat color and sensory properties did not differ between the breeds. The current study indicated that the breeds had a similar characteristics in meat quality. However, further research on consumer preference including Hanwoo needs to be undertaken.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.221-226
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• 2003

This study investigated the effect of different electrical stunning methods on pH, water holding capacity(WHC), cooking loss(CL), meat color and blood spot rate in broilers. One-hundred and forty broiler chickens were slaughtered by 50, 65 and 90 voltage with the same electrical frequency(255 Hz) and stunning time(5 sec) in commercial abattoir. The ultimate pH of leg muscle and WHC of breast muscle decreased with increasing the stunning voltage. However, there were no significant differences in ultimate pH, WHC and CL of breast muscle, and ultimate pH of leg muscle. Lightness(L*) and yellowness(b*) values of leg muscle stunned with 90V, 255 Hz, 5 sec were higher than those stunned with 50V, 255 Hz for 5 sec(p<0.05). But there were no significant differences in color value on skin, breast and wing muscle. Our experiments showed that change of stunning voltage affected some broiler meat quality parameters. However, further research is necessary to examine the effects of stunning condition on broiler meat quality.

• Food Science of Animal Resources
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• v.22 no.3
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• pp.222-227
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• 2002

Efficacy of submersion aging in chilled water of vacuum-packed Hanwoo beef was investigated. At 24 hours post-mortem, the somimemebranosus portion of Hanwoo carcass was excised and sliced (2.5cm, thickness). After beef core samples(6$\textrm{cm}^2$${\times}$2cm) were prepared and vacuum packed, the samples were randomly assigned to the four treatments which were conventional refrigerator at 4$^{\circ}C$(control), conventional refrigerator at 1$^{\circ}C$(T1), submersion in chilled water at 4$^{\circ}C$(T2) and submersion in chilled water at 1$^{\circ}C$(T3). Samples were stored for 3, 7, 10 and 14 days to measure meat color(CIE L*, a*, b*), deoxymyoglobin, oxymyoglobin and metmyoglobin percentage, thiobarbituric acid reactive substance (TBARS) value, purge loss(%) and total heam pigment content. CIE a* value of samples was not significantly changed by treatment during the storage. However, metmyoglobin content of T2 samples was significantly (p<0.05) lower than those of control and T1,T3 during storage. Also, TBARS value of T3 samples was significantly (p<0.05) lower than those of control and T2 samples. T3 showed the lowest purge loss%, whereas control remarked the highest purge loss(%). Total heam pigment of all samples were not significantly changed during the storage. These results suggested that submersion aging in chilled water could keep the myoglobin stability and reduce lipid oxidation and purge loss of vacuum packed beef during storage.