• Journal of Nutrition and Health
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• 제27권8호
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• pp.856-863
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• 1994

To develop a optimized method for educing the errors associated with the estimation of portion size of foods, fuzzy-dta processing of portion size was performed. Cooked-rice was chosen as a food item. The experiment was conducted in two parts. First, to study the conceptions of respondents to bowl size(large, medium, small), 11 bowls of different size and shape were used and measured the actual weights of cooked-rice. Second, to study the conceptions of respondents to volume(1, 1/2, 1/3, 1/4), 16 different volumes of cooked-rice in bowls of same size and shape were used. Respondents for this study were 31 graduate students. After collecting the data of respondents to size and volume, fuzzy sets of size and volume were produced. The critical values were calculated by defuzzification(mean of maximum method, center of area method). The differences of the weights of cooked-rice in various bowl size and volume between the critical values and the calculated values by average portion size using in conventional methods were compared. The results hows large inter-subject variation in conception to bowl size, especially in large size. However, conception of respondents to volume is relatively accurate. Conception to bowl size seems to be influenced by bowl shape. Considering that the new fuzzy set was calculated by cartesian product(bowl size and volume), bowl shape should be considered in estimation of bowl size to make more accurate fuzzy set for cooked-rice portion size. The limitations of this study were discussed. If more accurate data for size and volume of many other food items are collected by the increased number of respondents, reducing the errors associated with the estimation of portion size of foods and rapid processing will be possible by constructing computer processing systems.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.305-320
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• 2017

The selection of subset size is of great importance to the accuracy of digital image correlation (DIC). In the traditional DIC, a constant subset size is used for computing the entire image, which overlooks the differences among local speckle patterns of the image. Besides, it is very laborious to find the optimal global subset size of a speckle image. In this paper, a self-adaptive and bidirectional dynamic subset selection (SBDSS) algorithm is proposed to make the subset sizes vary according to their local speckle patterns, which ensures that every subset size is suitable and optimal. The sum of subset intensity variation (${\eta}$) is defined as the assessment criterion to quantify the subset information. Both the threshold and initial guess of subset size in the SBDSS algorithm are self-adaptive to different images. To analyze the performance of the proposed algorithm, both numerical and laboratory experiments were performed. In the numerical experiments, images with different speckle distribution, different deformation and noise were calculated by both the traditional DIC and the proposed algorithm. The results demonstrate that the proposed algorithm achieves higher accuracy than the traditional DIC. Laboratory experiments performed on a substrate also demonstrate that the proposed algorithm is effective in selecting appropriate subset size for each point.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1240-1245
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• 2003

Reduced activation ferritic steel (JLF-1) is considered as a promising candidate material for blanket or first-wall structure of D-T fusion reactors. The fracture tests of fracture resistance curve (J-R curve) and $J_{IC}$ are desirable to investigate the exact fracture toughness of JLF-1 steel, since it has a high ductility. The fracture toughness of JLF-1 steel is affected by the configuration of test specimen such side groove, specimen thickness or specimen size. In this study, the fracture toughness tests were performed with various size(plane size and thickness) and various side groove of specimens. The test results showed the standard specimen with the side groove of 40 % represented a valid fracture toughness. The fracture resistance curve increased with increasing plane size and decreased with increasing thickness. However, the fracture resistance curve of half size specimen was similar to that of the standard specimen.

• Journal of Communications and Networks
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• 제4권2호
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• pp.108-117
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• 2002

TCP, which was developed on the basis of wired links, supposes that packet losses are caused by network congestion. In a wireless network, however, packet losses due to data corruption occur frequently. Since TCP does not distinguish loss types, it applies its congestion control mechanism to non-congestion losses as well as congestion losses. As a result, the throughput of TCP is degraded. To solve this problem of TCP over wireless links, previous researches, such as split-connection and end-to-end schemes, tried to distinguish the loss types and applied the congestion control to only congestion losses; yet they do nothing for non-congestion losses. We propose a novel transport protocol for wireless networks. The protocol called VS-TCP (Variable Segment size Transmission Control Protocol) has a reaction mechanism for a non-congestion loss. VS-TCP varies a segment size according to a non-congestion loss rate, and therefore enhances the performance. If packet losses due to data corruption occur frequently, VS-TCP decreases a segment size in order to reduce both the retransmission overhead and packet corruption probability. If packets are rarely lost, it increases the size so as to lower the header overhead. Via simulations, we compared VS-TCP and other schemes. Our results show that the segment-size variation mechanism of VS-TCP achieves a substantial performance enhancement.

• 한국수산과학회지
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• 제37권4호
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• pp.323-329
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• 2004

In situ particle size and volume concentration of suspended sediment was measured at the mouth of Seomjin River Estuary In February 2001, using an optical instrument, 'LISST-100'. Time variation of in situ particle size and concentration shows: (1) during ebb tide, Seomjin River supplies relatively fine-grained particles with less-fluctuated, compared to during flood tide, and well-behaved concentrations following the tidal cycle; and (2) during flood tide, relatively coarse-grained particles with highly variable in size distribution and concentration flow upstream from Kwangyang Bay. This explains a poor correlation $(r^{2}=0.10)$ between sediment concentration and beam attenuation coefficient during flood and a high degree of correlation $(r^{2}=0.80)$ during ebb tide. Relatively fine grained and well defined, monotonous size distribution may promote the correlation between concentration and beam attenuation coefficient due to optical homogeneity of particles during ebb tide. Abundance of large aggregates with time-varying size and shape distributions may be mainly responsible for variations in optical properties of the sediment during flood tide, and thus may confound the relationship between the two variables. The difference in particle sizes and shapes between flood and ebb tides can also be observed on SEM images.

• 한국재료학회지
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• 제30권5호
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• pp.223-230
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• 2020

As a case study on aspect ratio behavior, Kaolin, zeolite, TiO₂, pozzolan and diatomaceous earth minerals are investigated using wet milling with 0.3 mm media. The grinding process using small media of 0.3 pai is suitable for current work processing applications. Primary particles with average particle size distribution D₅₀, ~6 ㎛ are shifted to submicron size, D₅₀ ~0.6 ㎛ after grinding. Grinding of particles is characterized by various size parameters such as sphericity as geometric shape, equivalent diameter, and average particle size distribution. Herein, we systematically provide an overview of factors affecting the primary particle size reduction. Energy consumption for grinding is determined using classical grinding laws, including Rittinger's and Kick's laws. Submicron size is obtained at maximum frictional shear stress. Alterations in properties of wettability, heat resistance, thermal conductivity, and adhesion increase with increasing particle surface area. In the comparison of the aspect ratio of the submicron powder, the air heat conductivity and the total heat release amount increase 68 % and 2 times, respectively.

• 한국결정성장학회지
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• 제30권4호
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• pp.123-130
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• 2020

AGM 연축전지(Absorbent Glass Mat Lead-Acid Battery)의 수명 특성을 결정짓는 양극 활물질(Active Material)의 주요 구성 결정인 4BS(Tetrabasic lead Sulfate)의 입자 크기를 제어하기 위해 4BS Nano Seed(NS)를 적용 중에 있다. 4BS NS 적용 시, 나노 입자 특성상 분산 안정성이 저하되어 제 기능을 다하지 못한다. 이를 개선하기 위해 기존 첨가제인 광명단(Red Lead)에 나노 입자의 4BS seed가 포함된 Incorporated Nano Seed(INS)를 함량별로 첨가하여 양극판 분석과 제품 성능을 평가하였다. INS 함량이 증가할수록 4BS 입자 크기는 작아지면서 균일해지는 특성을 확인할 수 있었으며, 반응 비표면적 증가에 따른 고율 방전 특성도 향상되는 것을 알 수 있었다. 극판 제조 공정에서의 개별 극판에 대한 입도 분포의 편차를 확인하기 위해, AGM 연축전지 200 대 대한 내부 저항 및 전압 검사를 진행하였으며 제품 제조 공정 품질 편차가 감소하는 것을 확인하였다.

• Applied Microscopy
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• 제32권4호
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• pp.311-317
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• 2002

입자 크기에 따라 상전이 경로가 달라지며 매우 큰 응집체로 존재하는 gibbsite 분말과 같은 재료의 정량적인 전이 구조 분석의 전제로서 입자 크기가 선택적인 TEM 시편의 준비가 절실히 요구된다. 입자 크기 선택성을 실현한 TEM 시편 준비의 방법론을 확립하기 위한 방안으로서 본 실험이 전개되었다. 약 1 wt%의 gibbsite 원료 분말을 에탄올 용매에 혼합 한 뒤, ball-milling에 의해 조분쇄 처리를 하고 증류수에 1 : 19의 비로 희석된 분산 조제, Darvan C, 0.25 vol%의 첨가와 함께 ultrasonic 처리를 하여 gibbsite suspension을 만들었다. 제조된 gibbsite suspension의 누적 농도 변화 관찰에 의한 침강 시간의 조정 후 정적 침강 분리에 의해 nm 크기별로 분리된 TEM 시편을 만들 수가 있었다. 시편의 전체적인 양상은 SEM으로 관찰하였고 개개 입자들의 morphology 는 TEM으로 분석하였다. 또한, 공정 과정 중의 상변화 가능성을 검토하기 위해 XRD 분석을 실시하였다.

• 한국응용곤충학회지
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• 제16권2호
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• pp.105-113
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• 1977

한국산 불개미의 다형현상에 있어서 일개미의 몸의 크기와 임무수행과의 관계, 유시웅의의 시맥상의 변이, 성비 및 소의 크기에 따르는 일개미번데기의 형별발생과 일개미집단의 형별구성등에 관하여 조사한 결과를 요약하면 다음과 같다. 1. 일개미는 3형으로 분화되어 있으며, 소형은 주로 소의 내부에 동료집단의 보호와 외부에서 진딧물에 방문하는 임무를, 그리고 대형과 중간형은 주로 외부에서 식이운반, 조소 및 동료집단의 보호임무를 수행한다. 그러나 소형이 진딧물에 방문하는 임무는 반드시 고정되어 있는 것이 아니고 계절에 따라 다소 변동이 있는 것 같다.

• 한국통신학회논문지
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• 제13권5호
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• pp.390-399
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• 1988

계산 과장이 비교적 간단하고 실시간 처리가 가능한 coding방법 중의 하나인 BTC(Block Truncation Coding)를 이용하여 영상 데이터를 압축하기 위하여 2진 영상에서 주로 사용하는 quar tree 개념을 도입하여 압축율을 개선시키고, 기존의 BTC와 그 성능을 비교하였다. 이 논문에서 제안하는 방법은 그레이 레벨의 변화가 적은 영역에서는 부화상의 크기를 크게 하고, 그레이 레벨의 변화가 큰 영역에서는 부화상의 크기를 작게 하여 전체 부화상의 갯수를 줄임으\ulcorner\ulcorner영상 데이타의 압축을 행하였다. 또한 비트 평면의 효율적인 전송을 위하여 큰 크기의 부화상에 있어서는 Huffman run-length code를, 작은 크기의 부화상에 있어서는 lookup rable방식을 이용하였다. 컴퓨터 시뮬레이션 결과, 크기가 256x256이고, 그레이 레벨이 256인 영상에서 평균 0.8bit/pel의 압축 효과를 얻었다.