• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.465-468
• /
• 2000

The interference situation for the satellite networks using non-geostationary satellite orbit (NGSO) is more complicated than the situation between geostationary satellite orbit (GSO) networks because of the time varying orbital characteristics of NGSO systems. Most of frequency bands are allocated to fixed-satellite service and liked-service in co-primary basis. In this paper, the sharing criteria between NGSO/FSS systems and HDFS (High Density Fixed-Service) are examined.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.451-455
• /
• 1993

Interaction between system and disturbance results in system with time-dependent parameter. Parameter variation due to interaction has random characteristics. Most of the randomly varying parameters in control problem is regarded as white noise random process which is not a realistic model. In real situation those random variation is colored noise random process. Modified F-P-K equation is proposed to get the response of the random parametric system using some correction factor. Proposed technique is employed to obtain the colored noise parametric system response and confirmed via Monte-Carlo Simulation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2002.11a
• /
• pp.15-18
• /
• 2002

Power supply technique for electrodeless lamps, especially Endura of Osram, is presented in this paper. The power supply uses a conventional power factor correction technique due to its proved performance. But in the inverter stage, resonant converter with parallel loading scheme is used to mitigate the variation of matching circuit characteristics by time varying load. Less performance but sufficient to predict future success compared to Osram's one is verified as a result of experiment of the prototype.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.13-16
• /
• 2004

Power supply technique for electrodeless lamps is presented in this paper. The power supply uses a conventional power factor correction technique due to its proved performance. But in the inverter stage, resonant converter with parallel loading scheme is used to mitigate the variation of matching circuit characteristics by time varying load. Experiment and performance comparison for both Endura md QL are performed and further study to commercialization are discussed.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.4
• /
• pp.629-631
• /
• 2012

In Cognitive Radio network, spectrum selection scheme is one of a important part to manage idle spectrums efficiently. However, in CR networks, they have to adopt time-varying channel availability to minimize the interference to primary users (PU), and be able to manage spectrum resources efficiently. In this paper, we proposed a modified PF scheduler which can be appropriate to schedule downlink CR users and channels, by considering the fairness and the throughput as well as the primary user characteristics of each channel.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 1999.02a
• /
• pp.73-76
• /
• 1999

Superconductors are dissipative when exposed to time-varying magnetic fields. To analyze the AC characteristics of the superconductor, one usually needs to know magnetization curves of it. A good magnetization curves can be obtained only in a homogeneous magnetic field. In this paper, we report the fabrication and test results of a homogeneous magnet, which aims to give background magnetic fields for the superconductor.

• Journal of Biomedical Engineering Research
• /
• v.9 no.1
• /
• pp.117-124
• /
• 1988

A new implementation of a noise tracking filter is prposed to eliminate time-varying 60 Hz noise and its harmonics and baselins wandering in biological signals. This technique was applied to ECG. Filter's notch frequency could track the power line frequency well and it showed much better characteristics than the conventional method.

• KSBB Journal
• /
• v.5 no.4
• /
• pp.377-382
• /
• 1990

The characteristics controlled drug release have been studied for biodegradable polymer matrix. Polymer matrix was prepared from glycerine, prednisolone and dextran. Mathematical analysis of the data showed that the release behavior actually conformed to the Higuchi's diffusion controlled model. The release time was increased as drug loading doses increased, whereas decreased as glycerine concentration increased. The release rate did not change by varying molecular weight of dextran.

• Tribology and Lubricants
• /
• v.13 no.3
• /
• pp.108-114
• /
• 1997

The electrical and frictional properties of new sintered-metal bearing (S-bearing) with varying loads and speeds were measured. Also those were compared with the same products(J-bearing) made in Japan and the conventionally used ball bearing. The test results show that the frictional values of S-bearing are less than those of J-bearing, and that S-bearing operates in full-hydrodynamic lubrication regime. The values of rating current, starting time and jitter reveal that S-bearing is superior to J-bearing as well as ball bearing.

• Transactions on Electrical and Electronic Materials
• /
• v.12 no.6
• /
• pp.245-248
• /
• 2011

The scaling down of metal oxide semiconductor field-effect transistors (MOSFETs) for the last several years has contributed to the reduction of the scaling variables and device parameters as well as the operating voltage of the MOSFET. At the same time, the variation in the electrical characteristics of MOSFETs is one of the major issues that need to be solved. Especially because the issue with variation is magnified as the drive voltage is decreased. Therefore, this paper will focus on the variations between electrical characteristics and drain voltage. In order to do this, the test patterned multi-finger MOSFETs using 90-nm process is used to investigate the characteristic variations, such as the threshold voltage, DIBL, subthreshold swing, transconductance and mobility via parasitic resistance extraction method. These characteristics can be analyzed by varying the gate width and length, and the number of fingers. Through this modeling scheme, the characteristic variations of multi-finger MOSFETs can be analyzed.