Learning automata-based solutions to the nonlinear fractional knapsack problem with applications to optimal resource allocation.

This paper considers the nonlinear fractional knapsack problem and demonstrates how its solution can be effectively applied to two resource allocation problems dealing with the World Wide Web. The novel solution involves a "team" of deterministic learning automata (LA). The first real-life problem relates to resource allocation in web monitoring so as to "optimize" information discovery when the polling capacity is constrained. The disadvantages of the currently reported solutions are explained in this paper. The second problem concerns allocating limited sampling resources in a "real-time" manner with the purpose of estimating multiple binomial proportions. This is the scenario encountered when the user has to evaluate multiple web sites by accessing a limited number of web pages, and the proportions of interest are the fraction of each web site that is successfully validated by an HTML validator. Using the general LA paradigm to tackle both of the real-life problems, the proposed scheme improves a current solution in an online manner through a series of informed guesses that move toward the optimal solution. At the heart of the scheme, a team of deterministic LA performs a controlled random walk on a discretized solution space. Comprehensive experimental results demonstrate that the discretization resolution determines the precision of the scheme, and that for a given precision, the current solution (to both problems) is consistently improved until a nearly optimal solution is found--even for switching environments. Thus, the scheme, while being novel to the entire field of LA, also efficiently handles a class of resource allocation problems previously not addressed in the literature.     

Nonparametric 1-D temperature restoration in lossy media using Tikhonov regularization on sparse radiometry data

Microwave thermometry has the potential to characterize thermal gradients in lossy materials down to a few centimeters depth. The problem of retrieving temperature profiles from sets of brightness temperatures is studied using Galerkin expansion of one-dimensional (1-D) temperature profiles combined with Tikhonov regularization and predefined boundary conditions. From a priori knowledge of the temperature field shape, smooth Chebyshev polynomials are used as basis functions in the series expansion. The proposed estimator does not require iterative calculations that are normally performed using conventional numerical methods for signal parameter estimation and is, thus, very fast. Noise effects versus bandwidth limitations (smoothness of solutions) are studied in terms of four performance indexes defined in the text. In general, statistical spread of the temperature estimator increases with increasing number of Chebyshev polynomials. Systematic deviation from true values (bias) decreases as the number of Chebyshev polynomials increases. Results show that smooth temperature profiles can be reproduced using 6-7 Chebyshev polynomials. With additional constraints such as boundary conditions and maxima localization, a three-frequency-band radiometric scan is sufficient to produce acceptable results in regions with low thermal gradients. As the spatial variability of the 1-D temperature profile increases, more radiometric bands (5-6) are required to provide nonbiased estimates.     

Does the aging of tenured academic staff affect the research performance of universities?

This paper examines the common contentions that the collective aging of tenured academic staff has negative effects on research performance of universities due to (a) negative effects of aging in itself, and (b) to a lack of newcomers who could revitalise the research. Data on academic staff and research at Norwegian universities over two decades have been used to examine these contentions. While older staff published less than their younger colleagues two decades ago, no differences in productivity are found today. Furthermore, during this period, a large increase in the number of post-doctoral fellows and PhD students has taken place, compensating for the aging of tenured staff.     

Strength and conflicting valence in the measurement of food attitudes and preferences

There is a trend in current attitude research to move away from a simple uni-dimensional view of attitude, towards examining a more multivariate concept of attitude. An extensive array of attitudinal properties or dimensions has been provided, defined and categorised as ‘attitude strength’. Attitude strength has only recently been adapted as a conceptual framework for research in marketing and consumer studies. Our objective in this paper is to introduce some of the attitude strength concepts and literature in order to improve the measure and understanding of research dealing with measurement of food preferences, perceived food quality and satisfaction with food products, food suppliers, etc. The paper takes a particular focus upon problems in comprehending the middlemost choice or neutrality when measuring attitude items along a traditional bipolar semantic differential or a bipolar hedonic preference scale. Through several propositions, we have outlined how future research should note that both attitude ambivalence (mixed feelings) and non-attitude (lack of confidence in evaluation) could be threats to comprehending the middlemost response alternative on a questionnaire as neutral when measuring food attitudes or preferences in the traditional way. Our approach should also deal with some of the shortcomings of analysing attitude–behaviour consistency when modelling food consumption behaviour.     

符合ZigBee协议的RF解决方案的实现

IEEE802.15,4/ZigBee是针对无线监测和控制系统的需求而设计的射频标准.设计者可以利用符合ZigBee标准的开发平台,进行ZigBee产品的开发,该平台由硬件和软件组成.这将大大缩短产品上市时间,并减少系统设计及ZigBee认证所需的费用.     

Effect of a changed temperature regime on the benthos of a norwegian regulated river

The lowermost 20 km of the River Surna, north-western Norway receives cool water during summer from a hypolimnetic release mountain reservoir. The benthic fauna is completely dominated by insects. Benthic densities immediately below the power station are much lower than at all other localities. Although benthic densities increase downstream of the power station, they never exceed the densities above. The dominant insect group, chironomids, can be divided into four categories according to their abundance and distribution above and below the power station: (1) rare or absent above, but common or abundant below; (2) abundant or common above but rare or absent below; (3) slightly less abundant below; (4) unchanged abundance. No major differences in the species composition were recorded for stonefilies, mayflies and caddisflies.     

Molecular dynamics of the 5-HT1a receptor and ligands

A 3-D model of the human 5-HT_1a receptor was constructed fromits amino acid sequence by computer graphics techniques, molecularmechanics calculations and molecular dynamics simulations. Themodel has seven -helical membrane spanning segments, which forma central core containing a putative ligand binding site. Electrostaticpotentials 1.4 Å outside the water accessible surfacewere mainly negative on the synaptic side of the receptor modeland at the postulated ligand binding site, and positive in thecytoplasmic domains. The negative electrostatic potentials aroundthe synaptic domains indicate that positively charged ligandsare attracted to the receptor by electrostatic forces. Moleculardynamics simulations of the receptor model with serotonin, ipsapirone,R(–)-methiothepin or S(+)- methiothepin in the centralcore suggested that up to 22 different amino acid residues mayform a ligand binding pocket, and contribute to the specificityof ligand recognition and binding.     

Detection of nematodes in cod (Gadus morhua) fillets by imaging spectroscopy

ABSTRACT:  A promising method for detection of parasites in whitefish fillets has been developed. By use of imaging spectroscopy it is possible to record both spectral and spatial information from an object. In this work it is shown that by applying a white light transmission setup and imaging spectroscopy to cod ( Gadus morhua ) fillets, it is possible to make spectral images containing information to differentiate between fish muscle and parasites. The spectral images are analyzed by discriminant partial least square regression as well as image-filtering techniques. The method identifies parasites on the surface of the fillets as well as embedded parasites. One parasite was detected at 0.8 cm below the fillet surface, which is 2 to 3 mm deeper than what can be found by manual inspection of fish fillets. The method is nonintrusive and should thus be feasible for industrial purposes.     

Plant quality and harvest in old meadows grazed by reindeer in spring

Dry matter (DM) production and nutritional quality of plants were recorded on an old meadow before, during and after it was grazed by reindeer (Rangifer tarandus tarandus; 15 reindeer ha⁻¹) in the spring of 1996 and 1997 in northern Norway. Mean herbage harvest after 54 and 50 days of growth including 25 and 24 days of reindeer grazing was 1217 ± 320 kg DM ha⁻¹ in 1996 and 2297 ± 495 kg DM ha⁻¹ in 1997 respectively. On ungrazed old meadow, in contrast (P < 0.05), mean herbage harvest after 54 and 50 days of growth was 4159 ± 1164 kg DM ha⁻¹ in 1996 and 3791 ± 275 kg DM ha⁻¹ in 1997 respectively. In 1997, mean herbage harvest after 50 days of growth including 7 days of grazing by reindeer was as high as 3441 ± 180 kg DM ha⁻¹ (P > 0.05). Crude protein content (% of DM) was 25% early in the growing season in both 1996 and 1997. After 54 and 50 days of growth including 25 and 24 days of reindeer grazing, crude protein content was about 17% of DM in both 1996 and 1997 respectively, compared with about 12% of DM in ungrazed old meadow in both years. In 1997, crude protein content was 13.3% of DM after 50 days of growth including 7 days of reindeer grazing. The grazed and ungrazed old meadow contained about 20% (of DM) water‐soluble carbohydrates throughout the summer in both years. Mean plant cell wall content in ungrazed plants harvested after about 50 days was higher (51.5 and 49.1% of DM; P > 0.05) compared with plant cell wall content in grazed meadow (49.0 and 46.4% of DM) in 1996 and 1997 respectively. In vitro dry matter digestibility (%) of herbage harvest using rumen fluid from domestic ruminants was about 10% higher (73.4 ± 0.30 and 75.7 ± 0.28) in samples from grazed meadow compared with ungrazed meadow (66.2 ± 0.93 and 65.4 ± 1.19) in 1996 and 1997 respectively. Reindeer grazing of old meadow in spring maintains the vegetation at a younger phenological stage during the growing season when compared with ungrazed meadow. Therefore grazing increased the quality of the herbage, but decreased herbage harvest under conditions of high grazing intensity. © 2000 Society of Chemical Industry