Peer-to-peer bichromatic reverse nearest neighbours in mobile ad-hoc networks

The increasing use of mobile communications has raised many issues of decision support and resource allocation. A crucial problem is how to solve queries of Reverse Nearest Neighbour (RNN). An RNN query returns all objects that consider the query object as their nearest neighbour. Existing methods mostly rely on a centralised base station. However, mobile P2P systems offer many benefits, including self-organisation, fault-tolerance and load-balancing. In this study, we propose and evaluate 3 distinct P2P algorithms focusing on bichromatic RNN queries, in which mobile query peers and static objects of interest are of two different categories, based on a time-out mechanism and a boundary polygon around the mobile query peers. The Brute-Force Search Algorithm provides a naive approach to exploit shared information among peers whereas two other Boundary Search Algorithms filter a number of peers involved in query processing. The algorithms are evaluated in the MiXiM simulation framework with both real and synthetic datasets. The results show the practical feasibility of the P2P approach for solving bichromatic RNN queries for mobile networks.     

A high-gain (Ga,Al)As/GaAs heterostructure bipolar transistor withan equilibrium-depleted spike-doped base

The fabrication is reported of a high-gain (Ga,Al)As/GaAs heterostructure bipolar transistor (HBT) with a p-spike-doped base that is depleted at equilibrium. The device structure, based on that proposed for a bipolar inversion-channel field-effect transistor (BICFET), was grown by molecular-beam epitaxy (MBE). Fabricated transistors, containing an AlAs/n-GaAs superlattice emitter layer, exhibited DC current gains of up to 500. Maximum current gains of tested devices occurred at collector current densities in the mid-10³ A cm ^-2 range. It is postulated that the induced base in these transistors is formed predominantly by the forward-bias action on the base-emitter junction     

InAlAs/InGaAs heterojunction bipolar transistors with AlAs etch-stop layer

A seven monolayer AlAs layer was used as an etch stop at the emitter-base heterojunction of an Npn In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As HBT. The etch-stop HBTs displayed higher DC gain and similar microwave performance when compared to devices without the AlAs layer.<>     

完美需要一点点坚持

"is still designing……"(设计中……)每当Joost van Bleiwijk在MSN上线的时候,都能看到他这段闪烁的签名。荷兰与这里时差7个小时,你却几乎总能在线上找到他,他很忙,工作起来几乎夜以继日。     

Vocal interaction at 3 months and cognitive skills at 12 years.

Measured the differential vocal responsiveness (DVR) of 12 3-mo-old normal firstborn male infants to vocal–visual stimulation by the mother vs a stranger. There was a significant correlation between Ss' DVR at 3 mo of age and their performance at 12 yrs of age on the Verbal subscale of the WISC-R, the Peabody Picture Vocabulary Test, and the Reading and Arithmetic subtests of the Wide Range Achievement Test. (1 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gamma irradiation of Aspergillus flavus strains associated with Indonesian nutmeg (Myristica fragrans)

Food Science and Biotechnology - The aims of this work were to investigate the effects of gamma irradiation on population, viability and aflatoxin B1 production of Aspergillus flavus strains...     

Sex differences in vocal interaction with mother and stranger in Greek infants: Some cognitive implications.

Studies in the US rarely find differences in the social–vocal behaviors of male and female infants, and when such differences are found, they favor females. The present study examined whether this pattern would hold true in Greece, where the parental preference for boys over girls could differentially affect rearing behavior. Ss were normal 3-mo-olds, 39 reared by their parents and 25 reared in an institution. Ss' vocal interaction pattern was assessed by differential vocal responsiveness (DVR) to mother/caretaker or a stranger during 3-min social–vocal interactions. Home-reared males had higher DVR scores than home-reared females, whereas no such sex difference was obtained for the institution-reared infants. Also, the affective voice quality rating of mothers talking to their sons was higher than that of mothers talking to their daughters, whereas no such difference existed in the way caretakers talked to the institution-reared infants. Results suggest that early differences in vocal-interactional patterns, and possibly cognitive processing, may be attributable to differences in parental behavior. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kinetics of enthalpy relaxation of milk protein concentrate powder upon ageing and its effect on solubility

Kinetics of enthalpy relaxation of milk protein concentrate (MPC) powder upon short-term (up to 67 h) storage at 25 °C and a_w 0.85, and long-term (up to 48 days) storage at 25 °C and a range of a_w values (0–0.85) were studied by differential scanning calorimetry (DSC). The short-term study showed a rapid recovery of enthalpy for the first 48 h, followed by a slower steady increase with time. The non-exponential β parameter was calculated using the Kohlrausch–Williams–Watts function and found to be 0.39. Long-term storage showed that enthalpy relaxation depends on both storage period and water activity. The enthalpy value was much less for lower moisture content (mc) (a_w ? 0.23, mc ? 5.5%) than for higher mc (a_w ? 0.45, mc ? 8%) samples for a particular storage period. The results suggest that the presence of more water molecules, in close proximity to the protein surface facilitates kinetic unfreezing and subsequent motion of molecular segments of protein molecules towards thermodynamic equilibrium. Although de-ageing of stored samples did not reverse storage-induced solubility losses, the timescale of enthalpy relaxation was similar to that of solubility loss. It is suggested that enthalpy relaxation within stored samples allows structural rearrangements that are responsible for subsequent solubility decreases.     

Double heterojunction bipolar transistor in Al/sub x/Ga/sub 1-x/As/GaAs/sub 1-y/Sb/sub y/ system

Double heterojunction bipolar transistors based on the Al/sub x/Ga/sub 1-x/As/GaAs/sub 1-y/Sb/sub y/ system are examined. The base layer consists of narrow band gap GaAs/sub 1-y/Sb/sub y/ and the emitter and collector consist of wider band gap Al/sub x/Ga/sub 1-x/As. Preliminary experimental results show that AlGaAs/GaAsSb/GaAs DHBTs exhibit a current gain of five and a maximum collector current density of 5*10/sup 4/ A/cm/sup 2/.<>