• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.7-10
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• 2000

Fast block motion estimation technique is proposed to reduce the computational complexity in video coding. In the conventional methods the size of search region is fixed. For small motion regions like background the small size of sea of search region is enough to find a block motion. But for active motion regions the large size of search region is preferred to figure out the accurate motion vector. Therefore, it is reasonable that a block motion is estimated in the variable search region (both the size and the position of it). That is to say, the search region varies according to the predicted motion characteristics of a block. The block motion in video frames has temporal continuity and then the search region of a current block is predicted using the block motion of previous blocks. The computational complexity of the proposed technique is significantly reduced with a good picture quality compared to the conventional methods.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권3호
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• pp.204-209
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• 2005

A small size broadband microstrip patch antenna with small ground plane has been fabricated using MEMS. Multiple layer substrates are used to realize small size and broadband characteristics. The microstrip patch is divided into 3 pieces and each patch is connected to each other using a metal microstrip line. The fabrication process is simple and only one mask is needed. Two types of microtrip antennas are fabricated. Type A is the micros trip antenna with metal lines and type B is the microstrip antenna without metal lines. The size of proposed microstip antenna is $8^{*}12^{*}2mm^{3}$ and the experimental results show that the antenna type A and type B have the bandwidth of 420 MHz at 5.3 GHz and 480 MHz at 5.66 GHz, respectively.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.603-604
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• 2006

A small size broadband microstrip patch antenna with small ground plane has been fabricated using MEMS. Multiple layer of high and low dielectric substrates are used to realize small size and broadband characteristics. The microstrip patch is divided into 4 pieces and each patch is connected to each other using a metal microstrip line. The fabrication process is very simple and only one mask is needed. Two types of microtrip antennas are fabricated. Type A is the microstrip antenna with metal lines and type B is the microstrip antenna without metal lines. The size of proposed microstip antenna is $8*12*2mm^3$ and the experimental results show that the antenna type A and type B have the bandwidth of 420MHz at 5.3 GHz and 480MHz at 5.66 GHz, respectively.

• Journal of the Korean Data and Information Science Society
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• 제21권6호
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• pp.1343-1351
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• 2010

Sample size determination is very important part in clinical trials because it influences the time and the cost of the experimental studies. In this article, we consider the Bayesian methods for sample size determination based on hypothesis testing. Specifically we compare the usual Bayesian method using Bayes factor with the decision theoretic method using Bayesian reference criterion in mean difference problem for the normal case with known variances. We illustrate two procedures numerically as well as graphically.

• 대한가정학회지
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• 제40권7호
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• pp.119-127
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• 2002

Fitness of clothes becomes a major concern in apparel industry. In order to improve clothing fitness, it's very important to suggest a systematical sizing system. The Purpose of this study was to suggest a standard sizing system for junior-high school girls'lower clothes. The subjects were 402 middle-high school girls of 13 to 15 year-old. 4 clusters were categorized by cluster analysis and the sizing system was classified according to four lower body types. The size intervals of waist girth and hip girth were 3cm and 4cm respectively. The most frequent size were 64-86 in the short and small figure type 1,67-90 in the fattest figure type 2, 61-86 in the average size type 3 and 64-90 in type 4 taller than others types. The sizing system, which had frequencies more than 4%, was classified 9 cases, 11 cases, 8 cases and 9 cases respectively by lower body types. This result will contribute to clothing fitness of consumer and the amount of production.

• 설비공학논문집
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• 제18권7호
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• pp.556-562
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• 2006

The objectives of this paper are to analyze simultaneous heat and mass transfer performance for a plate type bubble absorber with binary nanofluids numerically and to investigate the effects of binary nanofluids and surfactants on the size of the bubble absorber. The effective absorption ratio represents the effect of binary nanofluids and surfactants on the absorption performance. The kinds and concentrations of nano-particles and surfactants are considered as the key parameters. The results show that the addition of surfactants can reduce the size of absorber up to 74.4%, the application of binary nanofluids does the size up to 63.6%. Combination of binary nanofluids and surfactants can reduce the size of absorber up to 77.4%.

• 센서학회지
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• 제19권5호
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• pp.342-348
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• 2010

The wireless sensor networks have been extensively researched. One of the issues in wireless sensor networks is a developing energy-efficient clustering protocol. Clustering algorithm provides an effective way to extend the lifetime of a wireless sensor networks. In this paper, we proposed an energy efficient clustering scheme by adjusting group size. In sensor network, the power consumption in data transmission between sensor nodes is strongly influenced by the distance of two nodes. And cluster size, that is the number of cluster member nodes, is also effected on energy consumption. Therefore we proposed the clustering scheme for high energy efficiency of entire sensor network by controlling cluster size according to the distance between cluster header and sink.

• Smart Structures and Systems
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• 제24권5호
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• pp.659-668
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• 2019

In digital image correlation, speckle image is closely related to the measurement accuracy. A practical global evaluation criterion for speckle image is presented. Firstly, based on the essential factors of the texture image, both the average particle size and image sharpness are used for the assessment of speckle image. The former is calculated by a simplified auto-covariance function and Gaussian fitting, and the latter by focusing function. Secondly, the computation of the average particle size and image sharpness is verified by numerical simulation. The influence of these two evaluation parameters on mean deviation and standard deviation is discussed. Then, a physical model from speckle projection to image acquisition is established. The two evaluation parameters can be mapped to the physical devices, which demonstrate that the proposed evaluation method is reasonable. Finally, the engineering application of the evaluation method is pointed out.

• 대한화학회지
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• 제7권2호
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• pp.133-139
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• 1963

It is well-known that high temperature hurts the sizing effect of rosin size in paper making, mainly owing to the particle size of rosin-aluminium complex in paper stock. In this experiments, author find, when the temperature of stock rises up. the particle size of rosin-aluminium complex of neutral rosin size increases and the degree of sizing decreases finally. However, the behavior of Bewoid size is quite opposite to former. This result showed that, Bewoid size is suitable in hot summer and neutral rosin size in cold winter for better sizing effect.

• 한국재료학회지
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• 제22권5호
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• pp.243-248
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• 2012

ZrN nanoparticles were prepared by an exothermic reduction of $ZrCl_4$ with $NaN_3$ in the presence of NaCl flux in a nitrogen atmosphere. Using a solid-state combustion approach, we have demonstrated that the zirconium nitride nanoparticles synthesis process can be completed in only several minutes compared with a few hours for previous synthesis approaches. The chemistry of the combustion process is not complex and is based on a metathesis reaction between $ZrCl_4$ and $NaN_3$. Because of the low melting and boiling points of the raw materials it was possible to synthesize the ZrN phase at low combustion temperatures. It was shown that the combustion temperature and the size of the particles can be readily controlled by tuning the concentration of the NaCl flux. The results show that an increase in the NaCl concentration (from 2 to 13 M) results in a temperature decrease from 1280 to $750^{\circ}C$. ZrN nanoparticles have a high surface area (50-70 $m^2/g$), narrow pore size distribution, and nano-particle size between 10 and 30 nm. The activation energy, which can be extracted from the experimental combustion temperature data, is: E = 20 kcal/mol. The method reported here is self-sustaining, rapid, and can be scaled up for a large scale production of a transition metal nitride nanoparticle system (TiN, TaN, HfN, etc.) with suitable halide salts and alkali metal azide.