• 한국재료학회지
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• 제16권11호
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• pp.681-686
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• 2006

Plasma nitrocarburising and plasma post oxidation were performed to improve the wear and corrosion resistance of S45C and SCM440 steel by a plasma ion nitriding system. Plasma nitrocarburizing was conducted for 3h at $570^{\circ}C$ in the nitrogen, hydrogen and methane atmosphere to produce the ${\varepsilon}-Fe_{2-3}$(N, C) phase. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of $500^{\circ}C$ for 1 hour. The very thin magnetite ($Fe_3O_4$) layer $1-2{\mu}m$ in thickness on top of the $15{\sim}25{\mu}m$ ${\varepsilon}-Fe_{2-3}$(N, C) compound layer was obtained by plasma post oxidation. A salt spray test and electrochemical testing revealed that in the tested 5% NaCl solution, the corrosion characteristics of the nitrocarburized compound layer could be further improved by the application of the superficial magnetite layer. Throttle valve shafts were treated under optimum plasma processing conditions. Accelerated life time test results, using throttle body assembled with shaft treated by plasma nitrocarburising and post oxidation, showed that plasma nitrocarburizing and plasma post oxidation processes could be a viable technology in the very near future which can replace $Cr^{6+}$ plating.

• 한국재료학회지
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• 제22권10호
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• pp.545-551
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• 2012

In semiconductor manufacturing, the circuit integrity of packaged BGA devices is tested by measuring electrical resistance using test sockets. Test sockets have been reported to often fail earlier than the expected life-time due to high contact resistance. This has been attributed to the formation of Sn oxide films on the Au coating layer of the probe pins loaded on the socket. Similar to contact failure, and known as "fretting", this process widely occurs between two conductive surfaces due to the continual rupture and accumulation of oxide films. However, the failure mechanism at the probe pin differs from fretting. In this study, the microstructural processes and formation mechanisms of Sn oxide films developed on the probe pin surface were investigated. Failure analysis was conducted mainly by FIB-FESEM observations, along with EDX, AES, and XRD analyses. Soft and fresh Sn was found to be transferred repeatedly from the solder bump to the Au surface of the probe pins; it was then instantly oxidized to SnO. The $SnO_2$ phase is a more stable natural oxide, but SnO has been proved to grow on Sn thin film at low temperature (< $150^{\circ}C$). Further oxidation to $SnO_2$ is thought to be limited to 30%. The SnO film grew layer by layer up to 571 nm after testing of 50,500 cycles (1 nm/100 cycle). This resulted in the increase of contact resistance and thus of signal delay between the probe pin and the solder bump.

• Journal of Genetic Medicine
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• 제17권1호
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• pp.39-42
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• 2020

The Senior-Loken syndrome was first described in 1961 as an oculo-renal disease consisting of familial juvenile nephronophthisis and Leber congenital amaurosis. It is a rare autosomal recessive disorder with a prevalence of 1:1,000,000 caused by mutations in nine genes (NPHP 1-8 and NPHP 10). Ocular manifestations (e.g., photophobia, nystagmus, and extreme hyperopia) occur within the first few years of life while renal manifestations (e.g., formation of multiple cysts impairing kidney function and end-stage renal disease) appear in late childhood to adolescence. Here, we report a case of a Filipino male presenting with rotatory nystagmus and progressive deterioration of vision since childhood. He had congenital amaurosis and juvenile nephronophthisis that progressed to end stage renal disease by age 19. All laboratory and imaging findings were consistent with chronic kidney disease. Molecular genetic testing of ciliopathy-related genes was performed revealing a homozygous mutation in exon 11 of the IQCB1/NPHP5 gene, c.1090C>T (p.Arg364^⁎). This sequence change created a premature translational stop signal resulting in a truncated protein product, nephrocystin-5 and its consequent loss of function. His symptoms eventually improved with initiation dialysis. The prognosis of Senior-Loken syndrome remains dismal and a high index of suspicion, early diagnosis and timely intervention of renal complications are warranted.

• 한국컴퓨터산업학회논문지
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• 제3권3호
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• pp.295-306
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• 2002

성공적인 프로젝트 계획은 활용 가능한 일정과 더불어 프로젝트를 완수하는데 요구되는 노력을 얼마나 정확히 추정하느냐에 달려있다. 새로운 또는 보다 나은 모델 개발에 많은 연구가 이루어졌지만 현존하는 소프트웨어 노력 추정 모델들은 생명주기 전반에 걸쳐 투입되는 총 개발노력과 단위시간당 소요되는 노력 함수만을 제공한다. 또한, Putnam은 세부단계별로 일정한 개발노력 투입 비율을 제시하였다. 그러나 소프트웨어의 규모, 복잡도와 운영환경의 영향으로 인해 프로젝트 별로 투입되는 총 개발노력의 규모에 차이가 발생한다. 그 결과, 개발 세부단계별로 투입되는 노력의 규모도 프로젝트마다 차이가 발생한다. 본 논문은 총 개발노력 변동에 따른 소프트웨어의 계획, 명세, 구축, 시험과 이행단계에 투입될 개발노력을 추정하는 기준을 제시하였다. 이 모델들은 183종의 다른 소프트웨어 프로젝트들로부터 유도되었다. 제안된 기준은 프로젝트의 일정과 노력 할당관리에 실질적인 지침을 제공할 것이다.

• Human Ecology Research
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• 제57권3호
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• pp.329-340
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• 2019

The 'Sliver-Spoon-Discourse' is currently witnessing growing complaints about the polarization and a sense of despair among many young people in Korean society. The 'Sliver-Spoon-Discourse' that compares one's subjective socioeconomic status to a spoon implies a sense of psychological superiority or deprivation. The present study empirically tested the current popular 'Sliver-Spoon-Discourse' based belongingness and explored how subjective socioeconomic status may affect the psychology of young people. This study examined the effects of subjective socioeconomic status on individual relative deprivation and subjective well-being. Data were collected from 307 undergraduate students enrolled at universities located in Seoul with both parents alive. The findings of this study were as follows. First, student respondents reported moderate levels of subjective socioeconomic status, relative deprivation, and subjective well-being. Second, after controlling for respondents' gender, age and family income, the students' subjective socioeconomic status was negatively associated with their level of relative deprivation. Finally, after controlling for respondents' sociodemographic characteristics, the students' subjective socioeconomic status was not significantly related to all the three sub-factors of life satisfaction, positive emotion and negative emotion as well as total subjective well-being. The results indicate that 'Sliver-Spoon-Discourse' based belongingness may instigate relative deprivation of young people without affecting their subjective well-being. The implications of the results are discussed for youth programs and policies.

• Computers and Concrete
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• 제20권6호
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• pp.635-643
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• 2017

The rehabilitation and strengthening of concrete structures using Fiber-Reinforced Polymer (FRP) materials have been widely investigated. As a priority issue, however, the effect of curing conditions on the bonding behavior between FRP and concrete structures is still elusive. This study aims at developing a prediction model to accurately capture the mode-II interfacial debonding between FRP strips and concrete under different curing conditions. Single shear debonding experiments were conducted on FRP-concrete samples with respect to different curing time t and temperatures T. The J-integral formulation and constrained least square minimization are carried out to calibrate the parameters, i.e., the maximum slip $\bar{s}$ and stretch factor n. The prediction model is developed based on the cohesive model and Arrhenius relationship. The experimental data are then analyzed using the proposed model to predict the debonding between FRP and concrete, i.e., the interfacial shear stress-slip relationship. A Finite Element (FE) model is developed to validate the theoretical predictions. Satisfactory agreements are obtained. The prediction model can be used to accurately capture the bonding performance of FRP-concrete structures.

• Clinical and Experimental Pediatrics
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• 제64권5호
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• pp.239-246
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• 2021

Background: The consequences of severe acute respiratory syndrome corona virus 2 on mother and fetus remain unknown due to a lack of robust evidence from prospective studies. Purpose: This study evaluated the effect of coronavirus disease 2019 (COVID-19) on neonatal outcomes and the scope of vertical transmission. Methods: This ambispective observational study enrolled pregnant women with COVID-19 in North India from April 1 to August 31, 2020 to evaluate neonatal outcomes and the risk of vertical transmission. Results: A total of 44 neonates born to 41 COVID-19-positive mothers were evaluated. Among them, 28 patients (68.3%) (2 sets of twins) were delivered within 7 days of testing positive for COVID-19, 23 patients (56%) (2 sets of twins) were delivered by cesarean section; 13 newborns (29.5%) had low birth weight; 7 (15.9%) were preterm; and 6 (13.6%) required neonatal intensive care unit admission, reflecting an increased incidence of cesarean delivery and low birth weight but zero neonatal mortality. Samples of cord blood, placental membrane, vaginal fluid, amniotic fluid, peritoneal fluid (in case of cesarean section), and breast milk for COVID-19 reverse transcription-polymerase chain reaction tested negative in 22 prospective delivery cases. Nasopharyngeal swabs of 2 newborns tested positive for COVID-19: one at 24 hours and the other on day 4 of life. In the former case, biological samples were not collected as the mother was asymptomatic and her COVID-19 report was available postdelivery; hence, the source of infection remained inconclusive. In the latter case, all samples tested negative, ruling out the possibility of vertical transmission. All neonates remained asymptomatic on follow-up. Conclusion: COVID-19 does not have direct adverse effects on the fetus per se. The possibility of vertical transmission is almost negligible, although results from larger trials are required to confirm our findings.

• 센서학회지
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• 제30권4호
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• pp.243-249
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• 2021

Humidity is an important physical quantity that is closely related with the quality of everyday life as well as the quality control of products in various industries. Here, we have developed a divided-flow type humidity generator of which humidity generation is faster than the saturator-based humidity generator in ppm level. The operation principle of the divided-flow humidity generator is first introduced. Then, the performance of the divided-flow humidity generator is verified by testing the radiosonde humidity sensor at low temperature. As a result, the humidity generated from the divided-flow humidity generator is consistent with the saturator-based precision humidity generator within 1.6% relative humidity in the range from 10% to 40% at -45 ℃. It is also found that the radiosonde humidity sensor shows measurement errors by 3% - 5% at -45 ℃ when it is only calibrated at room temperature. The response times of radiosonde humidity sensor using the divided-flow humidity generator are between about 2 and 9 minutes, whereas those by the saturator-based humidity generator are about 20 minutes. In this regard, the divided-flow humidity generator has a merit in terms of fast humidity changes for the calibration of radiosonde humidity sensors at low-temperatures.

• 한국콘텐츠학회논문지
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• 제19권8호
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• pp.609-619
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• 2019

본 연구는 지난 5월 서울에서 온라인 커뮤니티에 '대림동 여경 폭행'이라는 영상에서 주취자 제압에 나선 여경이 피의자와 몸싸움에서 밀리는 등 다소 무기력한 모습의 장면이 나옴에 따라 경찰의 체력검정에 대한 문제점은 무엇인지 이에 대한 개선방안을 제시하고자 한다. 경찰 체력검정은 직무수행과 연계성이 있어야 함에도 현실에서 적용하기 어려운 항목들로 구성되어 있어 비난의 대상이 되고 있다. 문제점으로 나타나고 있는 것은 체력검정 종목의 비현실성과, 체력검정 기준이 너무나도 낮게 선정되어 있으며, 남녀성별 기준의 불균형과 체력검정 방법의 비전문화로 신뢰성이 떨어진다는 것이다. 이에 대한 개선방안으로 첫째, 치안상황에 맞는 현장 활용 가능한 종목으로 개선되어야 하며, 체력검정 평가기준을 상향 조정하고 업무수행에 필요한 제도적 장치 마련과 경찰의 직업적 특수성에 따른 기준을 충족하지 못하고 있는 여경의 체력검사기준을 강화하고, 부상방지 및 효과적인 체력측정을 위한 과학적인 체력검정 시스템을 구축하여 대한민국이 세계 최고의 치안서비스를 제공하는 치안강국으로 자리매김하기를 기대해 본다.

• 해양환경안전학회지
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• 제25권4호
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• pp.476-481
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• 2019

화재의 초기 검출은 인명과 재화의 손실을 최소화하기 위한 중요한 요소이다. 불꽃과 연기를 신속하면서 동시에 검출해야 하며 이를 위해 영상 기반의 화재 검출에 관한 연구가 다양하게 진행되고 있다. 기존의 화재 검출은 불꽃과 연기의 특징을 추출하기 위해 여러 알고리즘을 거쳐서 화재의 검출 유무를 판단하므로 연산량이 많이 소모되었으나, 딥러닝 알고리즘인 합성곱 신경망을 이용하면 별도의 과정이 생략되므로 신속하게 검출할 수 있다. 본 논문에서는 선박 기관실에서 화재 영상을 녹화한 데이터로 실험을 수행하였다. 불꽃과 연기의 특징을 외각 상자로 추출한 후 합성곱 신경망 중 하나인 욜로(YOLO)를 이용하여 학습하고 결과를 테스트하였다. 실험 결과를 검출률, 오검출률, 정확도로 평가하였으며 불꽃은 0.994, 0.011, 0.998, 연기는 0.978, 0.021, 0.978을 나타내었고, 연산시간은 0.009s를 소모됨을 확인하였다.