Optimal joint utility based load balancing algorithm for heterogeneous wireless networks

The rapid development of mobile broadband services with continuously increasing traffic volumes has resulted in a number of challenges, including ubiquitous network coverage, high bandwidth, and reliable services for reasonable price, etc. To address these challenges, evolved packet system (EPS) is proposed as the evolution of the packet core network. While resource management and load balancing issues in EPS are discussed in 3GPP standardization, relatively few research works consider mechanism design for load information monitoring and evaluation. Furthermore, even though some load balancing algorithms have been proposed for integrated networks, the load balancing scheme design which achieves the optimization of joint system performance has not been extensively studied. In this paper, an inter-access system anchor based load balancing mechanism is introduced which performs load monitoring and evaluation for access gateways and networks, and an optimal load balancing algorithm is proposed for heterogeneous integrated networks. To characterize the performance of integrated networks, the concept of utility function is introduced and the comprehensive performance of integrated networks which support both single type service and multimedia service is modeled mathematically. Applying vertical handoff as an efficient mechanism for achieving load balancing, the optimal number of handoff users is obtained through solving the optimization problem. Numerical results demonstrate that load balancing between access networks can be achieved, and the optimal number of handoff users corresponding to the maximal joint network utility can be obtained.     

Influence of Loss Model on Design Discharge of Homogeneous Plane

By applying the kinematic wave method to a homogeneous, rectangular overland plane, the influence of the constant and proportional-loss models on the design discharge are examined. The examination shows that with the use of the proportional-loss model, there is no partial-area effect and the design discharge is governed by the full-area contribution. On the other hand, with the use of the constant-loss model, there is no partial-area effect if the loss rate is small. For larger loss rates, there is a partial-area effect; and for this case, the design is complicated, since there is a need to search for the critical storm that governs the partial-area effect. The characteristic of the critical storm is that its rate of decrease in rainfall intensity with duration equals the corresponding rate of increase in the contributing area. The preceding findings are consistent with the design concept in the rational method that uses the proportional-loss model, and the results from earlier studies that used the constant-loss model.     

Proton magnetic resonance imaging of lipid in pecan embryos

Magnetic resonance images of plant tissues typically are manifestations of water protons in tissues. Within oilseeds, however, lipids contain a major portion of the mobile protons, which should enable specific imaging of lipids. In this study, experiments were done to demonstrate spin-echo imaging (SEI) and chemical-shift imaging (CSI) of lipid within nonimbibed and imbibed embryos of pecan (Carya illinoensis), a high-lipid seed. Magnetic resonance spectra of airdry embryos contained a single major peak for lipid, whereas those of imbibed embryos contained separate peaks for water and lipid. This separation of spectral peaks enabled CSI of distributions of either lipids or water in imbibed embryos. A longer spin-spin relaxation time of lipid protons than of water protons in imbibed embryos allowed selective SEI of lipids in those embryos. SEI of normal, dry embryos revealed fairly uniform distribution of lipids across tissues. Similar images of embryos damaged by the fungusPhoma exocarpina or the insectZerara viridula were less intense than those of a normal embryo, reflecting the lower oil contents of the damaged embryos. Magnetic resonance imaging should provide a useful technology for studying lipid distribution and metabolism within oil seeds.     

The Dynamics of Indonesia's Urbanisation, 1980-2006

This study examines continuity and change in patterns of Indonesia's urbanisation during the boom economy until the decentralisation era, using data mainly from the National Population Census 1980-2000 and from the Village Potential (PODES) 2006. Urbanisation in Indonesia is still characterised by a heavy concentration of the urban population in a few large cities, notably the Jakarta Metropolitan Area (JMA), which might reflect an integration of Jakarta into the global economy. It might also reflect an interurban disparity, between large and smaller cities. The population on the fringes of large cities is growing rapidly, while in the inner cities it is increasing at a very low rate of growth. Urban spatial development in Java is shaping belts, which connect many of the large cities. The intermediate cities and small towns on the outer islands have a relatively higher population growth rate compared with those in Java, which might suggest that those towns and cities are playing a more significant role in regional development.     

Water absorption in internally cured mortar made with water-filled lightweight aggregate

The increased propensity for shrinkage cracking in low water-to-cement ratio (w/c) concrete has inspired the development of new technologies that can reduce the risk of early-age cracking. One of these is internal curing. Internal curing uses saturated lightweight aggregate to supply ‘curing water’ to low w/c paste as it hydrates. Significant research has been performed to determine the effects of internal curing on shrinkage and stress development; however, relatively little detailed information exists about the effects of internal curing on fluid transport properties such as water absorption or diffusivity. This study examines the absorption of water into mortar specimens made with saturated lightweight aggregates (SLWA). These results indicate that the inclusion of SLWA can reduce the water absorption of mortar specimens. This observation was reinforced with electrical conductivity measurements that exhibited similar reductions.     

One-pot foam-gelcasting/nitridation synthesis of high porosity nano-whiskers based 3D Si3N4 porous ceramics

Nano-whiskers based 3D Si₃N₄ porous ceramics (3D-NWSNPC) with high-porosity (about 91–93 %), low density (0.17–0.25 g/cm³), low thermal conductivity, and a certain degree of recoverability under cyclic compressive loading and reasonably strengths were prepared at 1423–1523 K via a one-pot foam-gelcasting/nitridation route using inexpensive commercial Si powders as starting materials and hexadecyl trimethyl ammonium bromide as foaming agent. After nitridation at 1523 K, the sample with an original solid loading of 12.5 wt% exhibited the highest compressive strength of 1.9 MPa, even though its density was lowered to 0.25 g/cm³. The sample nitrided at 1473 K had a relative density of 7.3 %. Its compressive and specific strength were respectively 1.1 MPa and 5.5 MPa·cm³ g^?1, and its thermal conductivity was as low as 0.074 W/(m K) (measured at 323 K). These outstanding properties would make the as-prepared 3D-NWSNPC a promising candidate for applications in catalysis, filtration, thermal insulation and many other important areas.     

Trajectory Tracking for Underwater Swimming Manipulators using a Super Twisting Algorithm

The underwater swimming manipulator (USM) is a snake‐like, multi‐articulated, underwater robot that is equipped with thrusters. One of the main purposes of the USM is to act like an underwater floating base manipulator. As such, it is essential to achieve good station‐keeping and trajectory tracking performance for the USM by using the thrusters and by using the joints to attain the desired position and orientation of the head and tail of the USM. In this ‘paper, we propose a sliding mode control (SMC) law, specifically the super‐twisting algorithm with adaptive gains, for the trajectory tracking of the USM's centre of mass. A higher‐order sliding mode observer is proposed for state estimation. Furthermore, we show the ultimate boundedness of the tracking errors. We demonstrate the applicability of the proposed control law and show that it leads to better performance than a linear PD‐controller.     

CRAMStrack: Enhanced Nonlinear RSSI Tracking by Using Circular Multi-Sectors

Indoor localization using a Received Signal Strength Indicator (namely, RSSI localization) has been considered a poor measurement for target tracking. The main cause of this inaccurate measurement is that RSSI’s behaviors heavily depend on environmental factors. That is, one significant challenge to localization using RSSI is that the strength of a signal varies with the environment confounding wireless communications power and signal control. In this paper, we propose Circular RSSI And Multi-Sector tracking (CRAMStrack), a novel approach to reducing the uncertainty of RSSI localization by modifying the relationship of RSSI-to-Distance (RtD), based on the sectors of a circle and the position of the tracked target. Traditional RSSI tracking uses one uniform RtD relationship to locate a target whereas CRAMStrack utilizes multiple RtD responses for each wireless sensor. The paper examines CRAMStrack’s tracking ability in a Euclidean space with estimation techniques. Real-world experiments demonstrate CRAMStrack in a testbed environment to locate targets in both stationary, linear, and non-linear movement patterns with single and group-based formations. The track accuracy was about 1.46m for moving targets, while CRAMStrack had a 40% reduction in Root Mean Square Error (RMSE) over Uni-RtD using neighboring sensor information.