• Journal of IKEEE
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• v.23 no.2
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• pp.403-406
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• 2019

We propose a low-loss on-chip transformer using an auxiliary primary part (APP) for an output matching network for fully integrated CMOS power amplifiers. The APP is designed using a fifth metal layer while the primary and secondary parts are designed using a sixth metal layer with a width smaller than that of the primary and secondary parts of the transformer to minimize the substrate loss and the parasitic capacitance between the primary and secondary parts. By adapting the APP in the on-chip transformer, we obtain an improved maximum available gain value without the need for any additional chip area. The feasibility of the proposed APP structure is successfully verified.

• The KSFM Journal of Fluid Machinery
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• v.2 no.4 s.5
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• pp.48-56
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• 1999

For the study on loss coefficients of turbine cascade with variation of incidence angle, the wind-tunnel tests were performed under the ranges in velocity of 10 m/s, 15 m/s, 20 m/s and incidence angles from $-20^{\circ}\;to\;20^{\circ}$ by intervals of $5^{\circ}$. Comparing our results with Soderberg's prediction, differences in loss coefficient were $2.5\%\;and\;2.8\%$ each for 10 m/s and 15 m/s. A large disagreement of $30.3\%$ was showed at 20 m/s freestream velocity. The comparisons of these test results with Ainley's prediction showed an $8\%$ difference in the case of 20 m/s freestream velocity. Test results were approximately comparable with Ainley's loss prediction's in incidence angles. Generally, averaged total pressure loss seemed to be decreased as Reynolds number increased. The total pressure loss coefficients were increased parabolically, as incidence angles were increased negatively and positively from $0^{\circ}$, in all speed ranges. At the far low freestream velocities, minimum loss accurred between $-5^{\circ}\;and\;+5^{\circ}$. But this minimum range narrowed the location of this range by shifting to the direction of the angle as freestream velocity was increased.

• Progress in Superconductivity and Cryogenics
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• v.23 no.4
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• pp.25-29
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• 2021

For the application of HTS wire to AC power equipment, a conductor with high current capacity and low loss is required. CORC^®, one of the high-current conductors manufactured using several HTS wires, is made by winding the wires in a spiral on a cylindrical former. Because the magnetization loss of a CORC^® conductor depends on the degree of magnetic coupling between the wires constituting the CORC^®, it is necessary to know the value of the magnetization loss of the CORC^® itself. In order to obtain an accurate loss value, it is necessary to know the effect of the ratio of the winding pitch of the CORC^® conductor in the pickup coil region sampling the magnetization loss signal. To confirm this effect, we prepare CORC^® samples having various winding pitches, and measure and compare the magnetization losses. In addition, the magnetization loss was measured while rotating the CORC^® samples and it was examined whether there was a difference in the magnetization loss according to the rotation.

• Monthly Notices of the Royal Astronomical Society
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• v.513 no.4
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• pp.5606-5610
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• 2022

Mass-loss of massive helium stars is not well understood even though it plays an essential role in determining their remnant neutron-star or black hole masses as well as ejecta mass of Type Ibc supernovae (SNe Ibc). Radio emission from SNe Ibc is strongly affected by circumstellar matter properties formed by mass-loss of their massive helium star progenitors. In this study, we estimate the rise time and peak luminosity distributions of SNe Ibc in radio based on a few massive helium star mass-loss prescriptions and compare them with the observed distribution to constrain the uncertain massive helium star mass-loss rates. We find that massive helium stars in the luminosity range expected for ordinary SNe Ibc progenitors (4.6≲log L/L_⊙≲5.2) should generally have large mass-loss rates (≳10^-6M_⊙yr^-1) in order to account for the observed rise time and peak luminosity distribution. Therefore, mass-loss prescriptions that predict significantly low mass-loss rates for helium stars in this luminosity range is inconsistent with the SN radio observations. It is also possible that massive helium stars shortly before their explosion generally undergo mass-loss enhancement in a different way from the standard radiation-driven wind mechanism.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.62-68
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• 2016

The fingerprint, which is one of the methods of indoor localization using WiFi, has been frequently studied because of its ability to be implemented via wireless access points. This method has low positioning resolution and high computational complexity compared to other methods, caused by its dependence of reference points in the radio map. In order to compensate for these problems, this paper presents a radio map designed algorithm based on the log-distance path loss model fusing a WiFi and BLE fingerprint. The proposed algorithm designs a radio map with variable values using the log-distance path loss model and reduces distance errors using a median filter. The experimental results of the proposed algorithm, compared with existing fingerprinting methods, show that the accuracy of positioning improved by from 2.747 m to 2.112 m, and the computational complexity reduced by a minimum of 33% according to the access points.

• The Journal of Korean Medicine
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• v.42 no.1
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• pp.46-58
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• 2021

Objectives: The purpose of this study is to report weight changes and analyze adverse events in diabetic patients with Gamitaeeumjowee-Tang for weight loss. Methods: A retrospective chart review of weight change and adverse events was performed during the 10-week weight loss program using Gamitaeeumjowee-tang with low-calorie diets for diabetics(n=61). Weight and BMI changes were compared before and after the program and calculated the percentage of people who lost more than 5% of their weight, also identified whether subjects felt satiated or not. Adverse events were evaluated in terms of causality, severity and system-organ classes. Results: After 10-week weight loss program, significant weight loss (5.9±2.32kg, 7.73% reduction from baseline) and BMI reduction (2.9±0.86) were reported (n=61). Those who lost more than 5 percent of their body weight accounted for 88.5%, and also 88.5% of the participants felt full to help control their appetite. In assessing the causality of adverse events, 'Unlikely' was the most common (66%) and in severity evaluations, almost all symptoms were mild. Insomnia was the most frequently reported during the first 8 weeks, and constipation was reported the most afterwards. Conclusions: A combination of Gamitaeeumjowee-tang and low-calorie diets for 10 weeks appears to help weight reduction without serious adverse events in diabetic patients. Future well-designed prospective clinical studies testing the effectiveness and safety of this weight loss program are warranted.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.484-487
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• 2004

Symmetric directional couplers are widely used in interferometers, switches, and various signal processing devices. Recently, several optical couplers using multimode fibers were reported, but these suffer from inefficient coupling of light into a branching fiber and/or low directivity. This paper presents the measurement and analysis of loss in the connection of optical fibers via the optical directional couplers. The functionality of the device is based on the principle that is symmetrical, the power in excited mode can be unambiguously directed into one of the output channel by varying and of its parameters. In this experiment, we measure the power of loss in the optical directional coupler at various radius of curvature. Before the measurement of loss in x-coupler, we polish the contact of the fiber surface in order that light can penetrate through another port. The results show that, when the radius of curvature is increased, the loss power is decreased and also approaches of the straight line case.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.219-223
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• 2017

In this paper, we calculated the losses in the high voltage lines of power distribution system. The losses caused by high voltage lines are calculated using maximum current, resistance, loss factor, and dispersion loss factor. The accurate extraction of these factors are very important to calculate the losses exactly. Thus, the maximum loads are subdivided to regions and calculated monthly for more accurate maximum current calculation. Also, the composite resistance is calculated according to the ratio of the used wire types. In order to calculate the loss factor, the load factors according to the characteristics of each region were calculated. Finally, the losses of the distribution system is calculated by adding the losses by the transformers and the low voltage lines.

• Proceedings of the KIEE Conference
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• 1999.11a
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• pp.52-55
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• 1999

In recent years, much attention has been paid to the voltage collapse phenomena. There has been reported many cases about the voltage collapse in many countries. These voltage collapse phenomena are known as the event that can occur due to reactive power deficits. This paper proposes an efficient method that can pursue the reactive power loss changes and gives the simple voltage collapse proximity indicator(VCPI) based on the reactive power loss sensitivities using optimal techniques. By comparing reactive power loss sensitivity with active power loss sensitivity, it is also proved that VCPI based on reactive power loss sensitivities is more effective. The developed VCPI is derived from the Jacobian matrix of Load Flow and the computational burden is very low and on-line implementation is possible. The proposed method is applied to a IEEE-14 bus test system and reliable and promising results are obtained.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.1
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• pp.42-46
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• 2010

One way of engineering education fiber optic splicing loss was introduced. To make high sensitivity fiber optic sensor it is required low loss of splicing. Hence in this paper splicing loss was selected in the experiments and the splicing loss was evaluated based on the engineering education. After trials in the experiments fiber optic splicing loss depended upon the experimental attitude and its environments.