• 한국정보통신학회논문지
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• 제7권2호
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• pp.239-249
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• 2003

웹이 인터넷 정보도구의 표준으로 자리잡게 됨에 따라 점점 더 많은 웹 사이트들이 만들어졌고, 동시에 더 많은 웹 주소 공간이 필요하게 되었다. 그러나 웹 주소를 나타내는 물리적 URL은 기억하기에 너무 길뿐 아니라 웹 사이트 내용을 직관적으로 나타내기 어려운 점이 많았다. 본 논문에서는 물리적 URL 대신 논리적 URL을 사용하여 이런 어려움을 개선할 수 있도록 하는 URL 전달 서버의 구현에 대해 고찰하였다. URL 전달서버는 HTTP 재방향 트랜잭션을 이용하는 도메인 매퍼와 BIND에 기반한 네임서버로 구성되어지며, 본 논문에서는 이들 상호간의 작용 및 동작에 대해 상세히 연구하였다. 실험 결과 URL 전달에 따른 시간은 현재의 인터넷 트래픽 조건에 비해 무시할 만한 수준인 것으로 나타났다.

• 한국정보통신학회논문지
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• 제15권7호
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• pp.1564-1572
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• 2011

본 논문에서는 증강현실을 위한 히스토그램 기반의 손 인식 기법을 제안한다. 손동작 인식은 사용자와 컴퓨터 사이의 친숙한 상호작용을 가능하게 한다. 하지만, 비젼 기반의 손동작 인식은 복잡한 손의 형태로 인한 관찰 방향 변화에 따른 입력 영상의 다양함으로 인식에 어려움이 따른다. 따라서 본 논문에서는 손의 형태적인 특징을 이용한 새로운 모델을 제안한다. 제안하는 기법에서 손 인식은 카메라로부터 획득한 영상에서 손 영역을 분리하는 부분과 인식하는 부분으로 구성된다. 카메라로부터 획득한 영상에서 배정을 제거하고 피부색 정보를 이용하여 손 영역을 분리한다. 다음으로 히스토그램을 이용하여 손의 특징점을 구하여 손의 형태를 계산한다. 마지막으로 판별된 손인식 정보를 이용하여 3차원 객체를 제어하는 증강현실 시스템을 구현하였다. 실험을 통해 제안한 기법의 구현 속도가 빠르고 인식률도 91.7%로 비교적 높음을 확인하였다.

• 한국가금학회지
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• 제21권2호
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• pp.83-92
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• 1994

In order to study performance enhancing effects of supplementary antibiotics (avoparcin, nosiheptide and enramycin), two feeding trials were conducted. In Experiment 1, 1, 040 male Arbor Acres were reared in floor pens for 6 wk. Chicks were assigned to one of the following four treatments: Basal diet(B), B+avoparcin 10 ppm, B+nosiheptide 2.5 ppm and B+enramycin 5 ppm. Each treatment had five replications of 52 chicks each. In Experiment 2, two antibiotics (avoparcin and enramycin) were compared in $2{\times}2$ (antibiotics$\times$sex) factorial design. One thousand broiler chicks were reared in floor pens for 6 wk. Each of the 4 treatments had five replications of 50 chicks each. The results of Experiment 1 showed that antibiotic treatments (enramycin, avoparcin and nosiheptide) significantly(P <0.05) improved weight gain. Feed/gain ratio of avoparcin treatment and enramycin treatment tended to he lower than the control but they were not statistically significant. Dressing percentages were high in avoparcin and enramycin treatments compared to the control and nosiheptide treatment. The number of E. coli and Cl. perfringens in ileum and cecal contents were decreased by antibiotic treatments. Moisture contents in excreta of the birds were not significantly affected by the treatments. Leg abnormality and mortality were not significaniy different among treatments. In Experiment 2, weight gain was significantly (P<0.01) different between sexes, but not between antibiotic treatments. Significant effects of antibiotics (P<0.01), sex (P<0.01) and interaction (P<0.05) were shown in feed in take. Feed/gain ratio of avoparcin treatment was significantly (P<0.01) lower than that of enramycin treatment. leg abnormality and mortality were not significantly different among treatments but those in male broiler tended to be higher than in female broilers. It was concluded that nonsystemic antibiotics supplemented to the broiler diets suppress undesirable microorganisms and improve broiler performace in general and avoparcin was most effective in improving feed/gain ratio.

• 한국포장학회지
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• 제21권3호
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• pp.91-96
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• 2015

Fruit and vegetables are subjected to complex dynamic stresses in the transportation environment. During a long journey from the production area to customers using parcel delivery service, there is always some degree of vibration present. Vibration inputs are transmitted from the vehicle through the packaging to the fruit. Inside, these cause sustained bouncing of fruits against each other and container wall. These steady state vibration input may cause serous fruit injury, and this damage is particularly severe whenever the fruit inside the package is free to bounce, and is vibrated at its resonance frequency. The determination of the resonance frequencies of the fruit and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. Instrumentation and technologies are described for determining the vibration response characteristics of the fruits with frequency range 3 to 150 Hz. The resonance frequency of the pear ranged from 53 to 102 Hz and the amplitude at resonance was between 1.08 and 2.48 G. The resonance frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.

• 한국포장학회지
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• 제13권1호
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• pp.19-23
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• 2007

Shock and vibration inputs are transmitted from the transporting vehicle through the packaging to the fruit. The vibration causes sustained bouncing of fruits against each other and the container wall. The steady state vibration input may cause serous fruit injury, and the damage is particularly severe if the fruits are bounced at its resonance frequency. The determination of the resonance frequencies of the fruits and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruits, and to understand the complex interaction between the components of the fruits when they relate to expected transportation vibration inputs. To analyze the vibration properties of the apples for optimum packaging design during transportation, random vibration tests were carried out. In the random vibration test, the resonance frequency and PSD of the packaged freight of apples in the test were in the range of 82 to 97 Hz and 0.0013 to $0.0021G^2/Hz$ respectively and the resonance frequency and PSD of the packaged apples in the test were in the range of 13 to 71 Hz and 0.0143 to $0.0923G^2/Hz$.

• 한국전산유체공학회지
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• 제21권4호
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• pp.40-45
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• 2016

The numerical simulation has been performed to predict the performance of the fire suppression system for cabin of shipboard enclosure. The present study aims ultimately at finding the optimal parametric conditions of the mist-injecting nozzles using the CFD methods. The open numerical code was used for the present simulation named as FDS (Fire Dynamics Simulator). Application has been done to predict the interaction between water mist and fire plume. In this study, the passenger cabin was chosen as simulation space. The computational domains for simulation in the passenger cabin were determined following the fire scenario of IMO rules. The full scale of the flow field is $W{\times}L{\times}H=4{\times}3{\times}2.4m^3$ with a dead zone of $W{\times}L{\times}H=1.22{\times}1.1{\times}2.4m^3$. The water mist nozzle is installed in ceiling center of 2.3 m height from the floor, and there are six mattresses and four cushions in the simulation space. The combination patterns of orifices to the main nozzle and the position to install nozzles were chosen as the simulation parameters for design applications. From the present numerical results, the centered-located nozzles having evenly combined orifices were shown as the best performance of fire suppression.

• 대한기계학회논문집B
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• 제37권5호
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• pp.531-538
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• 2013

원심압축기에서 볼류트는 임펠러와 디퓨저를 통해 나온 유동을 모아주는 역할을 한다. 압축기의 운전점에 따라 볼류트 내부 발생하는 와류의 세기나 패턴이 달라진다. 압축기 설부에서는 압축기의 운전점에 따라 재유입 유동의 특성이 변화하고, 이러한 특성은 압축기의 성능 및 탈설계점에서의 특성을 이해하는데 중요한 역할을 한다. 본 연구에서는 PIV를 이용하여 압축기의 운전점에 따라 볼류트 내부에 발생하는 스크롤 와류를 측정하였으며, 압축기 설부 근처에서 유동장을 측정한 결과 유량계수가 감소할수록, 설부 측에 발생하는 박리영역이 줄어들고 압축기로 재유입되는 유동이 커지는 것을 알 수 있다.

• Journal of Preventive Medicine and Public Health
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• 제50권6호
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• pp.393-400
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• 2017

Objectives: To relieve the financial burden faced by households, the Korean National Health Insurance (NHI) system introduced a "copayment ceiling," which evolved into a differential ceiling in 2009, with the copayment ceiling depending on patients' income. This study aimed to examine the effect of the differential copayment ceiling on financial protection and healthcare utilization, particularly focusing on whether its effects varied across different income groups. Methods: This study obtained data from the Korea Health Panel. The number of households included in the analysis was 6555 in 2008, 5859 in 2009, 5539 in 2010, and 5372 in 2011. To assess the effects of the differential copayment ceiling on utilization, out-of-pocket (OOP) payments, and catastrophic payments, various random-effects models were applied. Utilization was measured as treatment days, while catastrophic payments were defined as OOP payments exceeding 10% of household income. Among the right-hand side variables were the interaction terms of the new policy with income levels, as well as a set of household characteristics. Results: The differential copayment ceiling contributed to increased utilization regardless of income levels both in all patients and in cancer patients. However, the new policy did not seem to reduce significantly the incidence of catastrophic payments among cancer patients, and even increased the incidence among all patients. Conclusions: The limited effect of the differential ceiling can be attributed to a high proportion of direct payments for services not covered by the NHI, as well as the relatively small number of households benefiting from the differential ceilings; these considerations warrant a better policy design.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.748-755
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• 2018

Timber from fast-growing tree species is susceptible to by biodeterioration attack, particularly subterranean termites. Impregnation with methyl methacrylate (MMA) potentially increases wood resistance to subterranean termite attack. Four wood species, namely sengon (Falcataria moluccana), jabon (Anthocephalus cadamba), mangium (Acacia mangium), and pine (Pinus merkusii), were impregnated with MMA, and samples of untreated and imidacloprid-preserved wood were prepared for comparison purposes. Small stakes, sized 0.8 cm by 2 cm in cross section by 20 cm in the longitudinal direction, were inserted into the ground for 3 months, and the weight loss of each specimen was determined at the end of the test period. A factorial $4{\times}3$ completely randomized design was used for data analysis; the first factor was wood species, and the second factor was treatment. The results showed that MMA polymer loadings were 27.88%, 24.91%, 14.14%, and 17.81% for sengon, jabon, mangium, and pine, respectively, and amounts of imidacloprid retention were $7.56kg/m^3$, $5.98kg/m^3$, $5.34kg/m^3$, and $9.53kg/m^3$, respectively. According to an analysis of variance, wood species, treatment, and interaction of both factors significantly affected the weight loss of wood specimens. Mangium had the smallest weight loss, followed by pine, sengon, and jabon. MMA impregnation into the wood increased the resistance of wood samples to subterranean termite attack during in-ground testing, but the resistance level was lower than that of imidacloprid-preserved wood. Except for mangium wood, the MMA treatment did not significantly affect resistance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.261-261
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• 2013

The smart design of nanocatalysts can improve the catalytic activity of transition metals on reducible oxide supports, such as titania, via strong metal-support interactions. In this work, we investigatedtwo-dimensional Pt nanoparticle/titania catalytic systems under the CO oxidation reaction. Arc plasma deposition (APD) and metal impregnation techniques were employed to achieve Pt nanoparticle deposition on titania supports, which were prepared by multitarget sputtering and sol-gel techniques. APD Pt nanoparticles with an average size of 2.7 nm were deposited on sputtered and sol-gel-prepared titania films to assess the role of the titania support on the catalytic activity of Pt under CO oxidation. In order to study the nature of the dispersed metallic phase and its effect on the activity of the catalytic CO oxidation reaction, Pt nanoparticles were deposited in varying surface coverages on sputtered titania films using arc plasma deposition. Our results show an enhanced activity of Pt nanoparticles when the nanoparticle/titania interfaces are exposed. APD Pt shows superior catalytic activity under CO oxidation, as compared to impregnated Pt nanoparticles, due to the catalytically active nature of the mild surface oxidation and the active Pt metal, suggesting that APD can be used for large-scale synthesis of active metal nanocatalysts.