• 한국유체기계학회 논문집
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• 제18권6호
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• pp.57-62
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• 2015

The test of comparing liquid flow calibration system (approved by KOLAS) for accuracy and structure change test was performed in the test bed in order to evaluate the typical characteristics of the electromagnetic flow meters and parshall flume that are generally used in the water discharging facilities. The results of the accuracy comparing test with liquid flow calibration system showed the error of less than 2%. Pharshall plume got error up to -8.3% (low flow) from the flow rate test, but less than 4% from the accumulated flow test because of offset error at high flow rate and low flow rate. Evaluation of structual change test was tested with only parshall flume using structure and it consisted of installation angle (parshall flume and level sensor) and position change. Installation angle, water level sensor angle and position changing test for parshall flume had errors of 3.1%~-9.2%, 0.4%~-5.6% and 0.2%~1.3% respectively. Especially, the error showed the largest increase when the water level sensor measured the point of decreased flow by the structure change. Therefore, error factors (change of straight pipe length, installation of obstacle or effect of foreign substances on water level sensor) that can often occur in the field should be derived and the research for optimized installation method should be carried out continuously.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.687-690
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• 2015

전방 추돌 경보 시스템(FCWS) 및 차선 이탈 경보 시스템(LDWS)에서 차선 및 객체 검출을 위한 관심영역은 차도영역으로 설정되어야 한다. 분수계 분할(watershed segmentation)방법은 차도영역을 분리하기에 효과적인 알고리즘이다. 이 알고리즘은 초기 seed에 속해있는 watershed line과 국부 최소값에 따라서 분할 결과가 다르게 나타나는데 차도 seed에 그 이외의 영역이나 차량이 포함될 경우에 차도 이외의 부분이 차도영역으로 포함되어 분할된다. 이런 문제점을 보완하기 위해 도로 환경에 따라 차도 seed를 적응적으로 변경해야 한다. 그 방법으로 영상을 여러 개의 관심영역으로 분할하여 차선을 검출하고 자기차선을 잇는 직선을 초기 seed로 설정한다. 설정된 seed에 차량이 검출되면 seed 위치를 조정하고 조정된 위치에서 차선을 지나지 않는다면 차선을 지나도록 seed의 크기를 조정하여 최종적인 seed를 결정한다. 최종적으로 결정된 seed를 통해서 도로환경에 따라 적응적으로 차도영역을 검출을 가능하게 한다.

• 복식
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• 제59권8호
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• pp.49-65
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• 2009

As basic materials in this research, 874 pieces of engraving that recorded the garment produced by diverse authors in the 17-18th century were collected among the collections of male and female garment in the engraving kept by National Library of France and 216 pieces of engraving were classified among them to observe justaucorps as stated in the materials. Since type of justaucorps in the 18th century can be classified by difference in shape and change through the above engraving materials in large quantity and the shape and composition can be compared and analyzed with other materials such as picture, stored garment, written materials without difficulty, the chronology can be composed by single type of justaucorps. Intending to understand the change in composition caused by type classification and pattern making as per analysis of type property of justaucorps, the men's upper garment in France in the 18th century. Checking change in design per from and materials, justaucorps of 1680-1700s was in silhouette where waist in the length above knee was adhered and slightly spread to lower part. In the type of 1710-1750s, waist adhered remarkably and many pleats were made under waist to produce volume of form that spread to lower part like skirt. In the type of 1760-1780s, straight silhouette was attached to whole body and end of front adjustment in slant line turns to rear part. The developmental aspect of construction can be checked by making pattern. Changing the cutting line of body plate to smoothly connect section and to try to adhere to the body, the development of simpler and delicate pattern production technique was confirmed.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.146-152
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• 2007

An active micro-mixer, which was composed of an oscillating micro-stirrer in the microchannel to provide rapid, effective mixing at high flow, rates was analyzed. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight microchannel and microchannel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced and stabilized. Therefore, an optimum design for a dynamic micro-mixer with an oscillating stirrer was performed using Taguchi method in order to obtain a robust solution. The design parameters were established as the frequency, the length and the angle of the stirrer and the optimal values were determined to be 2, 0.8D and ${\pm}75^{\circ}$, respectively. It was found that the mixing index of the optimal design increased 80.72% compared with that of the original design.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.95-100
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• 2008

An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD(Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.0346, 0.66D and $\pm45^{\circ}$, respectively. It was found that the mixing index of the optimal design increased by 88.72% compared with that of the original design.

• 한국광학회지
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• 제11권5호
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• pp.335-339
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• 2000

본 논문에서는 2" BK7 유리 기판에 $Ag^+-Na^+$ 이온교환법을 이용한 $1.31/1.55\mu\textrm{m}$ 두파장 방향성 광 결합기를 제작하였다. 제작 및 모델링 조건으로는 이온교환 온도 $340^{\circ}C$, 이온교환 시간 12h, 확산이온농도 0.67[MF]-NaNO3+0.33[MF]-KNO3+1$\times$-3[MF]-AgNO3, 이었으며 굴절율의 분포는 폭 방향으로는 가우시안 함수로, 깊이 방향으로는 에러 함수 분포로 근사화 하였다. 광 결합기를 구성하는 채널 도파로의 폭은 단일 모드 조건으로부터 $4\mu\textrm{m}$이었고 간격은 $8\mu\textrm{m}$이었다. 제작된 소자의 전체 길이는 16mm이었으며 광 결합길이는 12.6mm이었고 $1.31/1.55\mu\textrm{m}$ 두파장에서 각각 18dB이상의 소멸비를 나타내었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권1호
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• pp.161-177
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• 2013

High-speed vessels require good resistance and seakeeping performance for safe operations in rough seas. The resistance and seakeeping performance of high-speed vessels varies significantly depending on their hull forms. In this study, three planing hulls that have almost the same displacement and principal dimension are designed and the hydrodynamic characteristics of those hulls are estimated by high-speed model tests. All model ships are deep-V type planing hulls. The bows of no.2 and no.3 model ships are designed to be advantageous for wave-piercing in rough water. No.2 and no.3 model ships have concave and straight forebody cross-sections, respectively. And length-to-beam ratios of no.2 and no.3 models are larger than that of no.1 model. In calm water tests, running attitude and resistance of model ships are measured at various speeds. And motion tests in regular waves are performed to measure the heave and pitch motion responses of the model ships. The required power of no.1 (VPS) model is smallest, but its vertical motion amplitudes in waves are the largest. No.2 (VWC) model shows the smallest motion amplitudes in waves, but needs the greatest power at high speed. The resistance and seakeeping performance of no.3 (VWS) model ship are the middle of three model ships, respectively. And in regular waves, no.1 model ship experiences 'fly over' phenomena around its resonant frequency. Vertical accelerations at specific locations such as F.P., center of gravity of model ships are measured at their resonant frequency. It is necessary to measure accelerations by accelerometers or other devices in model tests for the accurate prediction of vertical accelerations in real ships.

• 대한수학교육학회지:학교수학
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• 제12권1호
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• pp.45-60
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• 2010

학교수학에서 '각도'는 용어로서의 실효성을 상실한 반면에, '각의 크기' 라는 표현이 우세한 만큼, 그 표현의 수용을 고려할 필요가 있다. 교과서에서 각의 크기는 변의 길이와 관계없이 두 변이 벌어진 정도에 따라 다르다는 것을 명시할 필요가 있다. 해설서의 내용과 교과서의 내용을 일치시켜야 한다. 교과서에서는 각의 크기를 측정하기 위한 임의단위를 취급하지 않는다. 임의단위에 의한 각의 크기의 측정을 생각할 수는 있지만, 그것이 그다지 행해지지 않는다는 실정을 받아들여, 해설서에서 그것을 요구하지 않는 것을 고려할 필요가 있다. 해설서에서 1직각의 표준단위로서의 역할을 명시할 필요가 있고, 교과서에서도 그것을 활용하는 장면을 제시해야 한다. 교과서에서는 삼각형의 세 각의 크기의 합을 구하는 과정과 사각형의 네 각의 크기의 합을 구하기 위해 삼각형과 사각형을 각각 잘라 붙이는 과정에서, 학생들이 크기가 180도인 각과 360도인 각이 그림으로 어떻게 표현될 수 있는지 알고 있다는 것을 전제로 하고 있다. 그것은 비약이다.

• Journal of Animal Science and Technology
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• 제52권6호
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• pp.481-490
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• 2010

This study was conducted to characterize the morphological and behavior patterns of Sapsaree dogs. The population (n=8,256) has been constructed since 1990 over 12 generations and managed at the Sapsaree Breeding Research Institute, Gyeongsan, Gyeongbuk province. Eighteen morphological and seven behavioral traits were investigated for 882 individuals. Linear models were applied for each trait by fitting sex, season of birth, hair color or test age. The averages of body weight, body length, body height, and depth of chest were $20.5{\pm}2.4\;kg$, $57.3{\pm}4.2\;cm$, $52.1{\pm}3.6\;cm$, and $21.1{\pm}2.4\;cm$, respectively. Males had greater estimated values than females for these body conformation traits. The chocolate Sapsarees had greater averages for body weight, body height and chest depth. The older animals (>2 years) had heavier body weight than younger animals. About 54, 69, 97, 39 and 83.3% of the Sapsarees had hairs with yellow color, straight, medium to long, untangled, and longer around eyes, respectively. Also, about 40% brown eye, 43% curly tail, 78% normal jaw, 86% no missing teeth, 90% no dewclaw, and >90% with black nose, pendent ear, tongue without spots were observed. About 95% males were normal in testicles state. The males performed significantly better than the females for majority of the behavioral traits. For nerve stability, affability, wariness, adaptability, sharpness, activity, and reaction during blood drawn about 79%, 73%, 76%, 61%, 70%, 48% and 81% of the Sapsarees performed at desired level. In general, the Sapsarees showed good characteristics for both morphological and behavioral traits, which can be exploited to use the Sapsaree breed as a companion or guide dog.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.157-168
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• 2017

The pressure drop characteristics of air particle flow in a powder transport piping system were analyzed in this study. The pressure drop characteristics of air particle flow in the piping system have not well understood due to the complexibility of particle motion mechanism. Particles or powders suspended in the air flow cause the increase of the pressure drop and affect directly transport efficiency. In this study, the pressure drop in a powder transport piping system was analyzed with interactions of air flow and particle motion in straight and curved pipes. The total pressure drop increased with pipe length, mixture ratio, and friction factor of particles because of increased friction loss of air and particles in the piping system. For the coal powders of $74{\mu}msize$ and powder-to-air mass mixture ratio of 0.667, the total pressure drop under the consideration of powders and air flow was calculated as much as 30% higher than that air flow only.