🏛️國立陽明交通大學機構典藏

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Bayesian wavelet shrinkage for nonparametric mixed-effects models
(2000-10-01)
Huang, SY
;
Lu, HHS
;
統計學研究所
;
Institute of Statistics
The main purpose of this article is to study the wavelet shrinkage method from a Bayesian viewpoint. Nonparametric mixed-effects models are proposed and used for interpretation of the Bayesian structure. Bayes and empirical Bayes estimation are discussed. The latter is shown to have the Gauss-Markov type optimality (i.e., BLUP), to be equivalent to a method of regularization estimator (MORE), and to be minimax in a certain class. Characterization of prior and posterior regularity is discussed. The smoothness of posterior estimators is controlled via prior parameters. Computational issues including the use of generalized cross validation are discussed, and examples are presented.
A novel interference-resolving algorithm to support asymmetric services in TDD-CDMA systems with directional antennas
(2002)
Wang, LC
;
Huang, SY
;
Tseng, YC
;
電信工程研究所
;
Institute of Communications Engineering
This paper presents a new cross-slot interference-resolving algorithm for supporting unbalance traffic between downlink and uplink in TDD-CDMA systems. To avoid cross-slot interference between downlink and uplink, traditional algorithms typically require a global control on the transmission direction in each time slot among all cells. Obviously, this requirement significantly limits one of the key advantages in the TDD system -- enabling different rate asymmetry. We observe that the tri-sector cellular architecture possesses additional orthogonality inherently due to the directivity of directional antenna, which can provide an additional degree of freedom in allocating radio resource (i.e., time slots). Thus we propose a new distributed slot allocation algorithm based on the tri-sector cellular architecture. The advantage of the proposed algorithm is to enable a TDD-CDMA system to provide asymmetric services with different rates of asymmetry in all cells, thereby having more flexibility in handling uniform traffic patterns.
Hot-carrier induced degradations on RF power characteristics of SiGe heterojunction bipolar transistors
(2004)
Huang, SY
;
Chen, KM
;
Huang, GW
;
Hsu, TL
;
Tseng, HC
Hot-carrier (HC) effects on high-frequency and RF power characteristics of Si/SiGe HBTs were investigated in this paper. We found that the small-signal current gain, output power, and power gain of Si/SiGe HBTs are suffered by the HC stress. With different bias conditions, the degradations of cutoff frequency and output power were found to be worse under constant base-current measurement than that under constant collector-current measurement. These phenomena have been explained by the change of the current gain, transconductance, and base-emitter resistance under stress.
On the throughput performance of CSMA-based wireless local area network with directional antennas and capture effect: A cross-layer analytical approach
(2004)
Wang, LC
;
Huang, SY
;
Chen, A
;
電信工程研究所
;
Institute of Communications Engineering
In this paper we develop a cross-layer analytical approach front both the physical layer and the medium access control (MAC) layer to evaluate the performance of the IEEE 802.11 wireless local area network (WLAN). Front the physical layer, this analytical approach incorporates the effects of both capture and directional antenna, while front the MAC layer, our model takes account of the carrier sense multiple access with collision avoidance (CSMA/CA) protocol. Through a cross-layer modeling technique, this analytical framework can provide valuable insights of the physical layer impact on the throughput performance of the CSMA/CA MAC protocol. These insights can he helpful in developing a NLAC protocol to fully take advantage of directional antennas for enhancing the performance of the WLAN.
Impact of hot carrier stress on RF power characteristics of MOSFETs
(2005)
Huang, SY
;
Chen, KM
;
Huang, GW
;
Yang, DY
;
Chang, CY
This paper investigates hot-carrier (HQ effects on the RF power and linearity characteristics of MOS transistors using load-pull measurement. We found that the RF power characteristics are affected by the HC stress, and the linearity of MOS transistors is clearly degraded after HC stress at constant gate voltage measurement. However, at high gate voltage bias, the HC-induced power degradation is much reduced compared with that under low gate voltage regimes. In addition, HC effects on linearity can be softened by biasing the transistor at constant drain currents. These experimental observations can be explained by the change of threshold voltage, transconductance, subthreshold swing, and mobility degradation coefficient under HC stress.
Characterization and modeling of RF MOSFETs under hot carrier stress and oxide breakdown
(2006)
Huang, SY
;
Chen, KM
;
Huang, GW
;
Yang, DY
;
Chang, CY
Effects of hot carrier stress (HCS) and oxide breakdown (OBD) on the main figures-of-merit of RF MOSFETs are examined in this paper. We found that under the same dc degradation, the cut-off frequency (f(Tau)) and maximum oscillation frequency (f(max)) suffered mode seriously by OBD than by HCS. Minimum noise figure (NFmin) is one of the main concerns in RF characteristics. NFmin increased dramatically after OBD than that after HCS due to the added gate leakage paths. Those effects can be clarified and explained by using a constructed explained small-signal model.

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🏛️國立陽明交通大學機構典藏

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