• Title/Summary/Keyword: design bias

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Design Improvement and Measurement of a Rapid Single Flux Quantum Confluence Buffer

  • Baek, Seung-Hun;Kim, Jin-Young;Kim, Sehoon;Kang, Joonhee;Jungb, Ku-Rak;Park, Jong-Hyeok;Hahnb, Teak-Shang
    • Progress in Superconductivity and Cryogenics
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    • v.6 no.4
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    • pp.41-45
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    • 2004
  • Rapid Single flux quantum (RSFQ) confluence buffer is widely used in complex superconductive digital circuits. In this work, we have improved the currently used confluence buffer and obtained a more soundly designed confluence buffer. In simulations, improvements in the bias margins of 11 % and the global margins of 10%, compared to the previously used confluence buffer, were achieved. Global margins are very important in estimating a process error range allowed in fabrications. We used two circuit simulation tools, WRspice and Julia, to design and optimize the confluence buffer. We used Xic to obtain a mask layout. We fabricated the improved circuits by using Nb technology. The test results at low frequency showed that the improved confluence buffer operated correctly and had a very wide main bias margin of +/-43% enhanced from +/-26% of the previously used confluence buffer.

A Study on the Marking Efficiency of A-line Skirt (A-line Skirt의 Marking 효율에 관한 연구)

  • Uh Mi-Kyung
    • Journal of the Korea Fashion and Costume Design Association
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    • v.8 no.1
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    • pp.69-79
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    • 2006
  • The purpose of this study is to find the proper width of fabric which can bring high efficiency on productivity. We focus on the marking method by comparing and analyzing the marking efficiency of A-line skirt. This study employs 4 criteria to mark the A-line skirt, which are cutting method, angle, width, and direction, respectively. There can be 2 different cutting methods(fold pattern and add seam pattern at the front and back center line), and 2 different angles(warp angle and bias angle). Also, width of the fabric can be classified into 2 groups(110cm, 150cm), and marking direction can be grouped into 2(one direction marker and one direction per each size marker). These 4 criteria make 16($2^*2^*2^*2$) cases for this study. Main findings are follows. First, the skirt with folded at the center line had higher efficiency rate than the skirt with add seam at the center line. Second, the skirt with the 150cm width has higher efficiency rate than that of 110cm. Third, fixing the warp angle has higher efficiency rate than that of fixing the bias angle at the front and back center line. Finally, one direction per each size marker has much higher efficiency than the one direction marker.

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Effects of hippotherapy on children with cerebral palsy: systematic review and meta-analysis

  • Kim, Kwon-Hoi;Lee, Suk-Min
    • Physical Therapy Rehabilitation Science
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    • v.9 no.1
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    • pp.55-65
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    • 2020
  • Objective: The most important goal of hippotherapy is to improve function, gait, and balance. The purpose of this study was to investigate the effects of hippotherapy on function, gait, and balance of children with cerebral palsy (CP). Design: A systematic review and meta-analysis. Methods: We've searched the PubMed, EMBASE, and Cochrane Library CENTRAL databases for English experimental studies published up until September 2018. To analyze the effects of hippotherapy on the function, gait, and balance of children with cerebral palsy, the systematic review and meta-analysis were performed on Patient/Participants/Population Problem, Intervention, Comparison, Outcome with Timing, Setting Study Design. Papers retrieved from the database were removed from the literature management database. Methodological quality evaluation was evaluated using Cochrane's risk of bias. Data was analyzed using the Revman 5.3 program of the Cochrane library. Results: In this study, we found that the effect size of hippotherapy, denoted as d, was -3.82, and that hippotherapy had the most effect on gait, but no statistical significant difference was observed. We also found no significant difference in function and balance after hippotherapy. It was found from the funnel plot that there was no publication bias as the plot was symmetrically distributed around the dotted line. Conclusions: There are many unclear studies and a lack of randomized controlled trials (RCTs) in this research area. More RCTs on the effects of hippotherapy on children with CP should be conducted in the future.

Loss Calculation of a High Power DC-DC Converter Considering DC Bias Characteristic of Inductor (인덕터의 DC 바이어스 특성을 고려한 대용량 DC-DC 컨버터의 손실계산)

  • Jo, Young-Chang;Choi, Ju-Yeop;Jung, Seung-Ki;Choy, Ick;Song, Seung-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.789-795
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    • 2011
  • It is necessary to accurately predict converter losses for optimized design of a high-power DC-DC converter. The losses of switching devices and inductor among the elements of the converter take significantly greater proportion. The current ripple will be determined by the size of the inductance and this inductance value varies depending on the DC amount of inductor current. As the inductance changes according to load current, the change influences not only the inductor loss itself but also the total converter loss. In this paper, for more accurate design of a bi-directional DC-DC converter for 30kW-class energy storage system, more accurate computational model is proposed considering inductance variation according to the load current change. The inductance changes using variable magnetic cores are verified and converter efficiency is tested through simulations and experiments.

Safety and Efficacy of Low Level Laser for Alopecia : A Systematic Review (탈모에 대한 레이저의 안전성 및 유효성 : 체계적 문헌 고찰)

  • Lee, Bo-Ram;Lee, Ma-Eum;Ko, Kyoung-Sook;Seo, Hyung-Sik
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.32 no.4
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    • pp.90-100
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    • 2019
  • Objectives : The purpose of this study is to determine the safety and efficacy of low level laser. Methods : We searched 11 electronic databases(Pubmed, CAJ, EMBASE, Medline, Cochrane Library, KMBASE, KISS, KISTI, NDSL, RISS, Oasis) up to March 2019. We included randomized controlled trials(RCTs) using low level laser for alopecia. The methodological quality of each RCT was assessed by the Cochrane risk of bias tool. Results : 8 RCT studies were eligible in our review. The meta-analysis of 2 studies showed favorable results for the use of low level laser with minoxidil 5% than minoxidil 5% and 6 studies showed favorable results for the use of low level laser than placebo light. The results of meta-analysis showed that low-level laser has an efficacy on alopecia. There were no serious side effects or adverse effects. High risk of bias were observed in all studies. Conclusion : Now limited evidence is available to support low level laser for alopecia and further well-designed RCTs should be encouraged.

The Significant Roles of Corporate Counselors to Reduce Employee Stress for Enhancing their Performance

  • PARK, Joo-Young;KIM, Seong-Gon
    • The Journal of Industrial Distribution & Business
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    • v.13 no.8
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    • pp.1-7
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    • 2022
  • Purpose: The present study concentrates on the issues that affected the employees directly and acted as stress factors. These stress factors affect how the employees perform while undertaking their duties. Furthermore, this study evaluated how the involvement of the corporate counsel affected the company by enhancing the productivity of the employees. Research design, data and methodology: The research design of this research is a literature content analysis and method for data handling should be described, and the resultant combination of the studies should include the consistency measures for every meta-analysis. Specify any risk assessment of bias that may impact the cumulative evidence, such as the publication bias and the selective reporting within studies. Results: The finding shows that change in the location of employees' organizational restructuring and the introduction of new technologies also contributed to significant organizational stress factors. These results show a substantial correlation between the magnitude of the adjustments' effects on employees' performance. Conclusions: The current study strongly concludes that counselors, through their prowess, can analyze and evaluate the stress factors that are evident among the employees and in the organization. Some of these factors may be office layout, organizational codes of ethics, organization rules, and employees' personal challenges.

A study on the Design of a stable Substrate Bias Generator for Low power DRAM's (DRAM 의 저전력 구현을 위한 안정한 기판전압 발생기 설계에 관한 연구)

  • 곽승욱;성양현곽계달
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.703-706
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    • 1998
  • This paper presents an efficient substrate-bias generator(SBG)for low-power, high-density DRAM's The proposed SBG can supply stable voltage with switching the supply voltage of driving circuit, and it can substitude the small capacitance for the large capacitance. The charge pumping circuit of the SBG suffere no VT loss and is to be applicable to low-voltage DRAM's. Also it can reduce the power consumption to make VBB because of it's high pumping efficiency. Using biasing voltage with positive temperature coefficient, VBB level detecting circuit can detect constant value of VBB against temperature variation. VBB level during VBB maintaining period varies 0.19% and the power dissipation during this period is 0.16mw. Charge pumping circuit can make VBB level up to -1.47V using VCC-1.5V, and do charge pumping operation one and half faster than the conventional ones. The temperature dependency of the VBB level detecting circuit is 0.34%. Therefore the proposed SBG is expected to supply a stable VBB with less power consumption when it is used in low power DRAM's.

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Optimum design on the commutation circuit of a current source inverter feeding on induction motor (유도전동기 구동을 위한 전류형 인버어터의 전류회로 최적설계에 관한 연구)

  • 노창주;홍순일
    • Journal of Advanced Marine Engineering and Technology
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    • v.9 no.3
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    • pp.250-256
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    • 1985
  • With the advant of thryistors having large peak inverse voltages, current-source inverters are becoming very popular to feed induction motors. But it is very difficult to analysis the commutation. Since the actual variation of current during commutation is neither instantaneous nor linear and is effected by many parameters. Minimized bias-time of reverse voltages during commutation is expressed in term of machine parameters, capacitor voltage, load current and so on. The minimized bias-time is computed with y and z and also the commuation mechanism is tested on 2.2 kw induction motor. The computed results are compared with the experimental results, and the results give a good information for designing the commutation mechanism.

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Optimal designs for small Poisson regression experiments using second-order asymptotic

  • Mansour, S. Mehr;Niaparast, M.
    • Communications for Statistical Applications and Methods
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    • v.26 no.6
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    • pp.527-538
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    • 2019
  • This paper considers the issue of obtaining the optimal design in Poisson regression model when the sample size is small. Poisson regression model is widely used for the analysis of count data. Asymptotic theory provides the basis for making inference on the parameters in this model. However, for small size experiments, asymptotic approximations, such as unbiasedness, may not be valid. Therefore, first, we employ the second order expansion of the bias of the maximum likelihood estimator (MLE) and derive the mean square error (MSE) of MLE to measure the quality of an estimator. We then define DM-optimality criterion, which is based on a function of the MSE. This criterion is applied to obtain locally optimal designs for small size experiments. The effect of sample size on the obtained designs are shown. We also obtain locally DM-optimal designs for some special cases of the model.

DESIGN OF THE RLG CURRENT STABILIZER CIRCUIT FOR ATTITUDE CONTROL IN THE SATELLITE (위성 자세제어용 RLG 전류 안정화 회로 설계)

  • Kim Eui-Chan;Choi Jae-Dong
    • Journal of Astronomy and Space Sciences
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    • v.23 no.2
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    • pp.161-166
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    • 2006
  • In this paper, we describe the RLG current stabilizer circuit for attitude control in the satellite. The RLG makes use of the Sagnac effect within a resonant of a HeNe laser. The difference between two discharge currents causes one of the gyro bias errors. The theoretical background and current stabilizer are introduced. It is verified that the circuit designed is applicable to the test of input voltage and temperature.