• Title/Summary/Keyword: bias reference

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Effects of preselection of genotyped animals on reliability and bias of genomic prediction in dairy cattle

  • Togashi, Kenji;Adachi, Kazunori;Kurogi, Kazuhito;Yasumori, Takanori;Tokunaka, Kouichi;Ogino, Atsushi;Miyazaki, Yoshiyuki;Watanabe, Toshio;Takahashi, Tsutomu;Moribe, Kimihiro
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.2
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    • pp.159-169
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    • 2019
  • Objective: Models for genomic selection assume that the reference population is an unselected population. However, in practice, genotyped individuals, such as progeny-tested bulls, are highly selected, and the reference population is created after preselection. In dairy cattle, the intensity of selection is higher in males than in females, suggesting that cows can be added to the reference population with less bias and loss of accuracy. The objective is to develop formulas applied to any genomic prediction studies or practice with preselected animals as reference population. Methods: We developed formulas for calculating the reliability and bias of genomically enhanced breeding values (GEBV) in the reference population where individuals are preselected on estimated breeding values. Based on the formulas presented, deterministic simulation was conducted by varying heritability, preselection percentage, and the reference population size. Results: The number of bulls equal to a cow regarding the reliability of GEBV was expressed through a simple formula for the reference population consisting of preselected animals. The bull population was vastly superior to the cow population regarding the reliability of GEBV for low-heritability traits. However, the superiority of reliability from the bull reference population over the cow population decreased as heritability increased. Bias was greater for bulls than cows. Bias and reduction in reliability of GEBV due to preselection was alleviated by expanding reference population. Conclusion: Cows are easier in expanding reference population size compared with bulls and alleviate bias and reduction in reliability of GEBV of bulls which are highly preselected than cows by expanding the cow reference population.

A Self-Biased Current Reference in $0.25{\mu}m$ CMOS Technology

  • Park, Jae-Woo;Yoo, Chang-Sik
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.635-636
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    • 2006
  • A self-biased CMOS current reference is described which provides supply and temperature independent bias current. The supply independency is obtained by subtracting two bias currents which have the same supply dependency. Unlike the conventional self-bias CMOS current reference, excellent supply independency can be obtained even with the minimum channel length devices and thus smaller area implementation becomes possible. The supply independent bias current is then applied to a temperature compensating circuit and as a result supply and temperature independent bias current is obtained. The current reference has been implemented in a $0.25{\mu}m$ standard CMOS technology. The active silicon area is only $45{\mu}m{\times}45{\mu}m$. The simulated temperature coefficient is 64ppm/$^{\circ}C$ in temperature range between $0^{\circ}C$ and $120^{\circ}C$. Supply voltage can be as low as 1.3V and the supply dependency of the current reference is measured to be smaller than 4500ppm/V. While providing $10.25{\mu}A$ output current, the current reference consumes $160{\mu}W$.

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Analyses of temperature change of a u-bolometer in Focal Plane Array with CTIA bias cancellation circuit (CTIA 바이어스 상쇄회로를 갖는 초점면 배열에서 마이크로 볼로미터의 온도변화 해석)

  • Park, Seung-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2311-2317
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    • 2011
  • In this paper, we study the temperature change of a ${\mu}$-bolometer focal plane array with a capacitive transimpedance amplifier bias cancellation circuit. Thermal analysis is essential to understand the performance of a ${\mu}$-bolometer focal plane array, and to improve the temperature stability of a focal plane array characteristics. In this study, the thermal analyses of a ${\mu}$-bolometer and its two reference detectors are carried out as a function of time. The analyses are done with the $30{\mu}m$ pitch $320{\times}240$ focal plane array operating of 60 Hz frame rate and having a columnwise readout. From the results, the temperature increase of a ${\mu}$-bolometer in FPA by an incident IR is estimated as $0.689^{\circ}C$, while the temperature increase by a pulsed bias as $7.1^{\circ}C$, which is about 10 times larger than by IR. The temperature increase of a reference detector by a train of bias pulses may be increased much higher than that of an active ${\mu}$-bolometer. The suppression of temperature increase in a reference bolometer can be done by increasing the thermal conductivity of the reference bolometer, in which the selection of thermal conductivity also determines the range of CTIA output voltage.

Temperature Stable Current Source Using Simple Self-Bias Circuit

  • Choi, Jin-Ho
    • Journal of information and communication convergence engineering
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    • v.7 no.2
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    • pp.215-218
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    • 2009
  • In this paper, temperature stable current and voltage references using simple CMOS bias circuit are proposed. To obtain temperature stable characteristics of bias circuit a bandgap reference concept is used in a conventional circuit. The parasitic bipolar transistors or MOS transistors having different threshold voltage are required in a bandgap reference. Thereby the chip area increase or the extra CMOS process is required compared to a standard CMOS process. The proposed reference circuit can be integrated on a single chip by a standard CMOS process without the extra CMOS process. From the simulation results, the reference current variation is less than ${\pm}$0.44% over a temperature range from - $20^{\circ}C$ to $80^{\circ}C$. And the voltage variation is from - 0.02% to 0.1%.

Modeling of Data References with Temporal Locality and Popularity Bias (시간 지역성과 인기 편향성을 가진 데이터 참조의 모델링)

  • Hyokyung Bahn
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.6
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    • pp.119-124
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    • 2023
  • This paper proposes a new reference model that can represent data access with temporal locality and popularity bias. Among existing reference models, the LRU-stack model can express temporal locality, which is a characteristic that the more recently referenced data has, the higher the probability of being referenced again. However, it cannot take into account differences in popularity of the data. Conversely, the independent reference model can reflect the different popularity of data, but has the limitation of not being able to model changes in data reference trends over time. The reference model presented in this paper overcomes the limitations of these two models and has the feature of reflecting both the popularity bias of data and their changes over time. This paper also examines the relationship between the cache replacement algorithm and the reference model, and shows the optimality of the proposed model.

A Study on the Farming Decision-making Process of Onion and Garlic Farmers by the Perspective of Behavioral Economics (양파와 마늘 농가의 행동경제학적 영농 의사결정 과정에 관한 연구)

  • Lee, Su-Mi;Kim, Ho
    • Korean Journal of Organic Agriculture
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    • v.32 no.1
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    • pp.25-37
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    • 2024
  • This study is to apply behavioral economics-an economics that studies actual human behavior based on cognitive psychology-to the farming decision-making process of onion and garlic farmers. Of behavioral economic theories, dual system theory and prospect theory (value function), heuristic and bias were surveyed and examined in the field. The reference point of farmers was farming experience of the previous year, and so they showed reference dependence and anchoring heuristic, not rational thinking on production cost plan. And they showed status quo bias that cultivated continuously the previous year or the present crop. This status quo bias is related to loss aversion propensity. Farmers did not usually change cultivating crops, in other words, they showed diminishing sensitivity-insensitive to those that the more revenue or loss was increased. This diminishing sensitivity is related to loss aversion propensity and status quo bias. Also, farmers had representativeness heuristic because they regarded auction price of Garakdong wholesale market as the standard price level despite various prices by production region. And farmers had the affect heuristic that they depended on producers' organization data more than the state-run research institute ones about cultivation intentions and actual situations.

Test Results of Wide-Area Differential Global Positioning System with Combined Use of Precise Positioning Service and Standard Positioning Service Receiver

  • Kim, Kap Jin;Ahn, Jae Min
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.1
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    • pp.43-48
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    • 2021
  • Most existing studies on the wide-area differential global positioning system (WADGPS) used standard positioning service (SPS) receivers in their observation reference stations which provide the central control station global positioning system (GPS) measurements to generate augmentation data. In the present study, it is considered to apply a precise positioning service (PPS) receiver to an observation reference station which is located in the threatened jamming area. Therefore, the reference station network consists of a PPS receiver based observation reference station and SPS receiver based observation reference stations. In this case, to maintain correction performance P1C1 differential code bias (DCB) should be compensated. In this paper, P1C1 DCB estimation algorithm was applied to the PPS/WADGPS system and performance test results using measurements in the Korean Peninsula were presented.

the Active Current Bias Control using Flyback Converter (Flyback Converter를 이용한 Active Current Bias 제어)

  • Hwang Seon-Nam;Lim Sung-Kyoo;Lee Jun-Young
    • Proceedings of the KIPE Conference
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    • 2006.06a
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    • pp.84-87
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    • 2006
  • 본 연구는 Current Mirror에 있어서 Active Current Bias에 관하여 기술하였다. Current mirror에서 Active Current Bias를 걸어주는 보편적인 방법은 Current Bias단에 저항을 연결하여 저항값을 조절함으로 해서 Current를 제어하는 방법을 사용한다. Reference 전류를 제어하는데 있어 새로이 제안하는 것은 Flyback Converter를 이용하여 Acitve Current Bias를 제어 하려 한다. 트랜지스터를 이용하여 Current Mirror Circuit를 구성하고 Current Bias 측에 Flyback Converter Circuit을 연결한다. Flyback Converter의 PWM의 Duty Ratio를 조절함으로 해서 전류를 제어하는 특징을 이용하여 Active Current Bias를 제어한다.

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Improvement of Sensing Performance on Nasicon Amperometric NO2 Sensors (나시콘 전류검출형 NO2 센서의 성능개선)

  • Kim, Gwi-Yeol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.10
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    • pp.912-917
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    • 2007
  • Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

Performance enhancement of launch vehicle tracking using GPS-based multiple radar bias estimation and sensor fusion (GPS 기반 추적레이더 실시간 바이어스 추정 및 비동기 정보융합을 통한 발사체 추적 성능 개선)

  • Song, Ha-Ryong
    • Journal of Korea Society of Industrial Information Systems
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    • v.20 no.6
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    • pp.47-56
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    • 2015
  • In the multi-sensor system, sensor registration errors such as a sensor bias must be corrected so that the individual sensor data are expressed in a common reference frame. If registration process is not properly executed, large tracking errors or formation of multiple track on the same target can be occured. Especially for launch vehicle tracking system, each multiple observation lies on the same reference frame and then fused trajectory can be the best track for slaving data. Hence, this paper describes an on-line bias estimation/correction and asynchronous sensor fusion for launch vehicle tracking. The bias estimation architecture is designed based on pseudo bias measurement which derived from error observation between GPS and radar measurements. Then, asynchronous sensor fusion is adapted to enhance tracking performance.