• 전력전자학회논문지
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• 제5권5호
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• pp.427-434
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• 2000

본 논문은 유도전동기의 직접벡터 제어 시스템에서 전동기가 기동 시 토크 충격없이 부드럽게 기동할 수 있는 기동기법을 제시한다. 정지모드에서는 고정자 전류만으로 고정자자속을 계산하는 방식을 사용하며, 기동 후 직접 벡터제어 모드에서는 프로그램어블 3-단계 저역필터로 고정자자속을 계산한다. 정지모드에서 직접벡터제어 모드로 변환 시 3-단계 저역필터의 시간지연으로 고정자 자속이 급격히 감소되어 토크 역시 갑자기 감소된다. 본 논문에서는 전동기가 기동 시 토크 충격을 방지하기 위한 고정자 자속의 피이드포워드 제어 기법을 제시하고, 시뮬레이션 및 실험을 통하여 이 기법의 타당성을 확인한다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1690-1694
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• 2002

Genetic parameters were estimated for birth weight and weaning weight from three year (1991-1993) data totalling 1100 records of 25 rams to 205 ewes of Indigenous Sabi flock maintained at Grasslands Research Station in Zimbabwe. AIREML procedures were used fitting an Animal Model. The statistical model included the fixed effects of year of lambing, sex of lamb, birth type and the random effect of ewe. Weight of ewe when first joined with ram was included as a covariate. Direct heritability estimates of 0.27 and 0.38, and maternal heritability estimates of 0.24 and 0.09, were obtained for birth weight and weaning weight, respectively. The total heritability estimates were 0.69 and 0.77 for birth weight and weaning weight, respectively. Direct-aternal genetic correlations were high and positive. The corresponding genetic covariance estimates between direct and maternal effects were positive and low, 0.25 and 0.18 for birth weight and weaning weight, respectively. Responses to selection were 0.8 kg and 0.14 kg for birth weight and weaning weight, respectively. The estimated expected correlated response to selection for birth weight by directly selecting for weaning weight was 0.26. Direct heritabilities were moderate; as a result selection for any of these traits should be successful. Maternal heritabilities were low for weaning weight and should have less effect on selection response. Indirect selection can give lower response than direct selection.

• 한국염색가공학회지
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• 제13권1호
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• pp.38-44
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• 2001

The adsorption ability of dyes on chitin, a natural polymer was investigated for decolorization of dye wastewater. Chitin was manufactured in lab by decalcification in dilute aqueous hydrochloric acid solution and deproteination in dilute aqueous sodium hydroxide solution with shrimp shells. Absorbance of residue solution of dyebaths after dye adsorptions of chtin were measured in varieties of dye concentration and dipping periods. Three kinds of Direct dyes -C.I. Direct Red 81 (red 81), C.I. Direct Brown l(brown 1) and C.I. Direct Green 26(green 26) - were used. Red 81 and brown 1 have smaller molecular weight than green 26. The results from experimentals were of]tamed as follows: 1) Adsorption of green 26 was improved in dyebath by addition of salt, but red 81 and brown 1 were not found any improvements. 2) Smaller size of chitin particles could be absorbed much more speedy. In this experiments, the smallest range of chitin particle size was $250\mu{m}$ and less. 3) The most efficient amount of chitin for 20m1 of dyebath was 0.2g, 4) Both of red 81 and brown 1 showed good and speedy adsorption abilities as dyestuffs of over 90 percent in just one minute in dyebath of 0.01% dye concentration. But green 26 was absorbed slowly because of its large molecular weight. It took 40minutes to absorb dyestuffs of over 90 percent in dyebath of 0.01% dye concentration.

• 태양에너지
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• 제20권2호
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• pp.31-42
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• 2000

Since the direct normal insolation is a main factor for designing any focusing solar system, it is necessary to evaluate its characteristics all over the country. We have begun collecting direct normal insolation data since December 1990 at 16 different locations and considerable effort has been made for constructing a standard value from measured data at each station. KIER(Korea Institute of Energy Research)'s new data will be extensively used by concentrating system users or designers as well as by research institutes. From the results, we can conclude that 1) Yearly mean $4,576kcal/m^2.day$ of the direct normal insolation was evaluated for clear day all over 16 areas in Korea. 2) Clear day's direct normal insolation of spring and summer were $4,710kcal/m^2.day$ and $4,960kcal/m^2.day$, and for fall and winter their values were $4,484kcal/m^2.day$ and $4,151kcal/m^2.day$ respectively. So, spring and summer were higher, and fall and winter were lower than the yearly mean value.

• ETRI Journal
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• 제35권1호
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• pp.120-130
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• 2013

This paper presents an analysis of resource assignment for multihop communications in millimeter-wave (mm-wave) wireless personal area networks. The purpose of this paper is to figure out the effect of using directional antennas and relaying devices (DEVs) in communications. The analysis is performed based on a grouping algorithm, categorization of the flows, and the relaying DEV selection policy. Three schemes are compared: direct and relaying concurrent transmission (DRCT), direct concurrent transmission (DCT), and direct nonconcurrent transmission (DNCT). Numerical results show that DRCT is better than DCT and DCT is better than DNCT for any antenna beamwidths under the proposed algorithm and policy. The results also show that using relaying DEVs increases the throughput up to 30% and that there is an optimal beamwidth that maximizes spatial reuse and depends on parameters such as the number of flows in the networks. This analysis can provide guidelines for improving the performance of mm-wave band communications with relaying DEVs.

• 천문학회지
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• 제38권2호
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• pp.319-324
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• 2005

To date, more than 150 exo-solar planets have been observed by various methods such as spectroscopic, photometric, astrometric, gravitational lensing, pulsar timing methods. However, all these are indirect methods; they do not directly image the planets. Only free-floating planets or their 'ana-log' have been directly detected so far. Thus the next milestone is the direct imaging of any kinds of planetary mass objects orbiting around normal (young) stars, which might have been associated with protoplanetary disks, the sites of planet formation. I will describe some SUBARU efforts to detect self-luminous young giant planets as companions as well as direct imaging of the protoplanetary disks of ${\~}$100 AU size. The results of near-infrared coronagraphic imaging with adaptive optics are briefly presented on AB Aur, HD 142527, T Tau, and DH Tau. Our results demonstrate the importance of high-resolution (${\~}$0.1 arcsec) direct imaging over indirect observations such as modeling based on spectral energy distributions. The SUBARU observations are a prelude to ALMA from the morphological point of view.

• 대한한방내과학회지
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• 제24권2_4호
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• pp.995-1006
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• 2003

Objective: The purpose of this study is to see whether pain in cancer patients is decreased by Eriobotryae Folium Fomentation. Methods: We examined the change in pain among six cancer patients, prescribing Eriobotryae Folium Fomentation. As for evaluating methods, we used the case history of pain, the direct evaluation of pain, the indirect evaluation of pain. The direct evaluation of pain is subdivided by the language expression, the non-language expression, and Visual analog scale(VAS). The indirect evaluation of pain is subdivided by the condition of walking, mood and the condition of sleep. Results: After two weeks, any remarkable pain decrease is not observed in both of the direct evaluation and indirect evaluation.

• 한국정밀공학회지
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• 제17권10호
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• pp.162-169
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• 2000

A Direct Drive Valve(DDV) hydraulic actuation system which is commonly used as an aircraft's control surface driving actuator has multi-loop control structure to ensure its safety operation. However, because of not perfect matching of one self channel characteristics with the others, the servo valve driving current of each channel can be widely different. Therefore, the long-time use of DDV actuator without any correction of these channel current offsets will cause the problem of performance or life expectancy degradation due to unwanted heats in the linear motor. A current equalization loop structure which can minimizes current offsets between channels is introduced and designed. The performance of the current equalization loop is investigated and verified through the analytic and experimental ways.

• 전기학회논문지
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• 제56권3호
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• pp.611-614
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• 2007

In this paper, a Direct Learning Control (DLC) method is presented to generate a virtual reference input for linear feedback systems to improve the output tracking performance. The original reference input is effectively modified by the DLC without any iterative learning process. The presented DLC is designed based on the information on the relative degree of a system and previously generated virtual reference inputs. It is illustrated by simulations that the virtual reference input generated by the proposed DLC can achieve high tracking performance, although the reference input cannot be appropriately shaped by using existing DLC methods.

• Asia Pacific Journal of Business Review
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• 제5권1호
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• pp.11-19
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• 2020

This study is a review on Risk analysis of foreign direct investments in innovative projects of Uzbekistan. The study will examine SWOT and PESTL analysis as an effective situation analysis tool which plays an important role in the fields of management, marketing, and in any fields of requiring strategic planning. SWOT is an analysis method used to evaluate the 'strengths', 'weaknesses', 'opportunities', 'threats' and PESTL is an analysis tool used for measuring the 'political', 'economical', 'social', 'technological' and 'low' risks involved in a various sphere of economy. In this study, firstly the essence of SWOT and PESTL analysis is explained, secondly the components of SWOT and PESTL analysis is examined. The paper includes risk analysis for further investigation to innovation sector of Uzbekistan economy.