In this paper model of integrated voice/data cellular wireless networks (CWN) are investigated. The unified approximate approach to calculate the desired Quality of Service (QoS) metrics in an isolated cell of such networks under two multi-parametric call admission control (CAC) strategies is developed. One of them is based on the guard channels scheme while the second is based on a threshold s...

Hando is an important issue in mobile communication systems. However, most previous studies were based on TDMA systems considering voice and data tra c with the same bit rate. Hando management for high rate tra c is required in multi-media CDMA systems. Hando management scheme for high rate tra c is proposed by using guard channels and Reservation-on-Demand queue control. The effects of the num...

Inward-rectifying K+ channels serve as a major pathway for Ca2+-sensitive K+ influx into guard cells. Arabidopsis thaliana guard cell inward-rectifying K+ channels are assembled from multiple K+ channel subunits. Following the recent isolation and characterization of an akt2/3-1 knockout mutant, we examined whether the AKT2/3 subunit carries the Ca2+ sensitivity of the guard cell inward rectifi...

Methyl jasmonate (MeJA) elicits stomatal closing similar to abscisic acid (ABA), but whether the two compounds use similar or different signaling mechanisms in guard cells remains to be clarified. We investigated the effects of MeJA and ABA on second messenger production and ion channel activation in guard cells of wild-type Arabidopsis (Arabidopsis thaliana) and MeJA-insensitive coronatine-ins...

Guard cells form stomatal pores that optimize photosynthetic carbon dioxide uptake with minimal water loss. Stomatal movements are controlled by complex signaling networks that respond to environmental and endogenous signals. Regulation of stomatal aperture requires coordinated activity of reactive oxygen species (ROS)-generating enzymes, signaling proteins, and downstream executors such as ion...

A multi-level dynamic guard channels (MLDGC) scheme to efficiently provide priority access for handoff calls over new calls in cellular systems is proposed. The switch between levels is controlled by the number of dropped calls. Each additional level has an increasing number of guard channels as triggered by the number of dropped calls. An analytical formulation of the steady state probabilitie...

This paper proposes a prioritized real-time admission control algorithm to support soft handoff calls with QoS assurance in both uplink and downlink signal to interference ratio (SIR) requirement. Admission control is formulated as a performance optimization model, in which the objective is to minimize handoff forced termination probability. The algorithm is based upon dynamic reserved channels...

In this paper, we develop a performance model of a cell in a wireless communication network where the effect of handoff arrival and the use of guard channels is inlcuded. Fast recursive formulas for the loss probabilities of new calls and handoff calls are developed. Monotonicity properties of the loss probabilities are proven. Algorithms to determine the optimal number of guard channels and th...

Introduction In plants as in animals, K+ channel activity is the major determinant of cell membrane conductance [1,2]. Kt channels are therefore involved in central physiological processes such as setting the resting cell membrane potential, transducing signals and shaping action-potential waveforms. In addition, in plant cells, K t channel activity is thought to be involved in long-term fluxes...

Electrical properties of the plasma membrane of guard cell protoplasts isolated from stomates of Vicia faba leaves were studied by application of the whole-cell configuration of the patch-clamp technique. The two types of K+ currents that have recently been identified in guard cells may allow efflux of K+ during stomatal closing, and uptake of K+ during stomatal opening (Schroeder et al., 1987)...