• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.250-253
• /
• 2009

This paper presents NR (No Reference) Quality assessment method for IPTV or mobile IPTV. Because No Reference quality assessment method does not access the original signal so it is suitable for the real-time streaming service. Our proposed method use decoding parameters, such as quantization parameter, motion vector, and packet loss as a major network parameter. To evaluate performance of the proposed algorithm, we carried out subjective test of video quality with the ITU-T P.910 ACR (Absolute Category Rating) method and obtained the mean opinion score (MOS) value for QVGA 180 video sequence coded by H.264/AVC encoder. Experimental results show the proposed quality metric has a high correlation (84%) to subjective quality.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2018년도 전력전자학술대회
• /
• pp.57-59
• /
• 2018

This paper presents a novel reference variable speed control scheme of a BLDC motor for the high-speed blender machine according to the current limit. Because of a pulsating load variation of a high-speed blender machine, the actual speed is pulsated by the current limit in the high-speed region. The proposed control scheme uses a variable reference speed to reduce the speed variation from the current limit in the constant power region. The pulsated load is occurred at the material crushing, then the pulsated load is reduced after grinding. The reference speed is smoothly reduced at the pulsated load variation, then the enough torque can make a constant speed during crushing. When the pulsating load is reduced, the reference speed is automatically increased to the original speed value. The proposed control scheme is verified by experimental result by practical blender machine.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
• /
• pp.138-139
• /
• 2007

The use of conventional Twyman and Fizeau interferometers inevitably fails in testing high precision optics because of errors always existing in reference elements producing the reference wavefront. Therefore it is necessary to apply to this task the interferometers of a radically new type, which are able to produce perfect reference wavefront with the help of light diffraction by a small obstacle or pinhole. In this paper new theoretical approaches and schematics of point diffraction interferometers are considered in detail with paying attention to constructive reliability. Such interferometers do not use reference optical surfaces and readily provide adequate estimation of errors and aberrations value of 0.01 wavelengths.

• Nuclear Engineering and Technology
• /
• 제48권2호
• /
• pp.299-303
• /
• 2016

Prompt gamma activation analysis using a thermal neutron-guided beam at Japan Atomic Energy Agency JRR-3M was applied for the precise determination of Si in silicon nitride ceramic reference materials [Japan Ceramic Reference Material (JCRM) R 003]. In this study, the standard addition method coupled with internal standard was used for the nondestructive determination of Si in the sample. Cadmium was used as internal standard to obtain the linear calibration curves and to compensate for the neutron beam variability. The analytical result of determining Si in JCRM R 003 silicon nitride fine powder ceramic reference materials using prompt gamma activation analysis was in good agreement with that obtained by classical gravimetric analysis. The relative expanded measurement uncertainty (k = 2) associated with the determined value was 2.4%.

• 한국정밀공학회지
• /
• 제22권5호
• /
• pp.45-54
• /
• 2005

The purpose of this research is to find a simple and accurate NURBS interpolator for CNC systems such as robot, CMM and CNC machine tools. This paper presents a new design of NURBS interpolator for CNC system. The proposed algorithm used the recursive characteristics of NURBS equation, the previous incremental value and chord length for the sake of a constant chord length. Simulation study was conducted to see the performance of the proposed interpolator with reference-word and reference-pulse method. Consequently, an accurate and simple NURBS interpolator was possible for modem CNC systems.

• 한국정밀공학회지
• /
• 제28권12호
• /
• pp.1366-1371
• /
• 2011

In ultra precision machining, it is necessary to adjust the horizontality and reference position of a workpiece in a noncontact manner. For this, a simple process by measuring impedance between a tool tip and a workpiece which are connected to impedance analyzer is proposed. As the distance between the tool and the workpiece gets closer, the reduction rate of impedance becomes higher over all frequency ranges. By setting threshold value of impedance reduction rate at specific frequencies through preliminary experiments, the distance between the tool and the workpiece can be predicted and it directly enables us to horizontalize the workpiece and to set the tool to the desired reference position.

• 대한전자공학회논문지SD
• /
• 제41권8호
• /
• pp.105-113
• /
• 2004

MRAM (Magneto-resistive Random Access Memory)은 자성체의 스핀 방향을 정보원으로 하는 비휘발성 메모리로 magneto-resistance 물질을 정보 저장 소자로 사용한다. 본 논문에서는 MRAM 시뮬레이션시 MTJ (Magnetic Tunneling Junction)의 hysteretic 특성, asteroid 특성, R-V 특성을 HSPICE에서 재현할 수 있는 새로운 macro-model을 제안하고 HSPICE에 적용하여 그 정확도를 검증하였다. 또한 종래의 reference cell 회로에 비하여 정확한 중간 저항 값을 유지하는 새로운 reference cell 회로를 제안하고 이를 본 논문에서 제안한 macro-model을 이용하여 검증하였다.

• 콘크리트학회논문집
• /
• 제21권3호
• /
• pp.377-386
• /
• 2009

ACI life-365 기준확산계수 모델은 NT build 443 방법에 의한 시험 결과들로부터 만들어졌다. 이 방법은 침지기간 동안의 시간평균 확산계수를 구하는 방법이므로 ACI에서는 침지기간 동안의 시간평균 확산계수를 기준확산계수로 정의한 것이다. ACI 모델에서는 재령에 따른 감소효과를 지수함수 형태로 표현하고 있으므로 이를 고려한 ACI 기준확산계수 모델의 수정이 필요하다. 이를 위해 본 연구에서는 염소이온 노출개시기를 고려한 확산방정식의 해석해를 유도하고, 이를 사용하여 NT build 443 방법의 시간평균 확산계수를 기준재령의 확산계수로 변환하였다. 연구결과 life-365 기준확산계수 모델은 기존 값 보다 10% 정도 증가되고 수정되어야 함을 밝혔으며, 이에 따라 NT build 443 방법과 NT build 492 방법의 기존관계를 수정하여 내구수명 평가에 이용할 수 있도록 하였다. JCI 확산계수모델과 ACI 확산계수모델의 직접적인 비교를 위하여 JCI 확산계수모델에 대응하는 기준확산계수를 유도하였으며, 이를 통해 JCI 모델보다 ACI 모델이 더 보수적인 결과를 나타내는 것을 확인하였다.

• Journal of Nutrition and Health
• /
• 제40권sup권
• /
• pp.3-8
• /
• 2007

Sugars are a ubiquitous component of our food supply and are consumed as a naturally occurring component of many foods and as additions to foods during processing, preparation, or at the table. Most fruits and dairy products are high in sugars and thus naturally occurring sugars are consumed as part of a healthy diet. Some countries developed recommended daily intake figures(daily values : DVs or guideline daily amounts: GDA) for nutrients, and some countries, but not most have developed DV/GDA for total sugars. Dietary Reference Intakes for Koreans established by the Korean Nutrition Society in 2005, did not include the reference values for total sugar or added sugar. The committee on Dietary Reference Intakes for sugar was constituted in 2006 and discussed whether to special added sugars or total sugar. Although added sugars are not chemically or physiologically different from naturally occurring sugars, many foods and beverages that are major sources of added sugars have lower micronutrient densities compared with foods and beverages that are major sources of naturally occuring sugars. But it was so hard to calculate a dietary intake of added sugar for Korean people, because there was insufficient information about contents of added sugar during processing or preparation of Korean food. Currently Korean or US food labels contain information on total sugars per serving but do not distinguish between sugars naturally present in food and added sugars. Therefore the committee decided to set the reference value for total sugar for Koreans. According to the recommended diet pattern for Koreans suggested by the Korean Nutrition Society, estimated sugar intake from the sugar containing food based on 2,000 kilocalories is 67 g or 13% of total energy. Based on the data available on risk of obesity, hypertension, hyperlipidemia, insulin resistance, and metabolic syndrome from the analysis of Korean NHANES, it was insufficient evidence to set a UL for total sugar, but tended to increase serum LDL cholesterol and obesity at over 20-25% of energy from total sugar when consumed with high carbohydrates. Therefore the committee on Dietary Reference Intakes for sugar set the Acceptable Macronutrient Distribution Range for total sugar as 10-20% of total energy intake.

• Journal of Community Nutrition
• /
• 제1권1호
• /
• pp.39-43
• /
• 1999

Anthropometric measurements, particularly weight and height, are the most commonly employed measures of nutritional status in epidemiologic studies because of their simplicity and ease of collection. However, the usefulness of the anthropometric indicator is controversial. The aim of this study was to evaluate the usefulness of the anthropometric indicator to represent the nutritional status of individual adult in epidemiologic studies. In order to evaluate the usefulness of the anthropometric indicator to represent the nutritional status of individual, the validity in terms of sensitivity and specificity of anthropometric indicators was estimated by comparing the biochemical indicators to the reference indicators. The relative validity of dietary intake indicators was also measured for comparison between the three indicators of biochemistry, anthropometry and dietary assessment. The results showed that sensitivity of weight and height and dietary indicators were 16.7 an 50.5, respectively comparing the reference value of 100 as biochemical indicator in identifying anemic adults. Whereas the sensitivity of weight and height and dietary indicators were 63.6 and 36.4, respectively comparing reference value of 100 in identifying hyperlipidemic individuals(obesity). In conclusion, the validity of weight and height is much lower than that of biochemical indicator, burt weight and height still has some usefulness in identifying anemic individuals. Especially, it is more useful in identifying hyperlipidemic individual adults thant in identifying anemic individuals.