The single machine earliness and tardiness scheduling problem: lower bounds and a branch-and-bound algorithm

This paper addresses the single machine scheduling problem with a common due date aiming to minimize earliness and tardiness penalties. Due to its complexity, most of the previous studies in the literature deal with this problem using heuristics and metaheuristics approaches. With the intention of contributing to the study of this problem, a branch-and-bound algorithm is proposed. Lower bounds and pruning rules that exploit properties of the problem are introduced. The proposed approach is examined through a computational comparative study with 280 problems involving different due date scenarios. In addition, the values of optimal solutions for small problems from a known benchmark are provided.

Self-Organizing Maps as a New Tool for Classification of Plants at Lower Hierarchical Levels

A chemotaxonomic analysis is described of a database containing various types of compounds from the Heliantheae tribe (Asteraceae) using Self-Organizing Maps (SOM). The numbers of occurrences of 9 chemical classes in different taxa of the tribe were used as variables. The study shows that SOM applied to chemical data can contribute to differentiate genera, subtribes, and groups of subtribes (subtribe branches), as well as to tribal and subtribal classifications of Heliantheae, exhibiting a high hit percentage comparable to that of an expert performance, and in agreement with the previous tribe classification proposed by Stuessy.

Lower level interior, C House, Coorparoo, Brisbane

View to landcape beyond from lower level interior.

Lower level floor plan, Brannigan House, St Lucia, Brisbane

Hand-drawn floor plan.

A method to lower the detection limit for optical beat signals from a frequency-dithered stabilized laser

A narrow absorption feature in an atomic or molecular gas (such as iodine or methane) is used as the frequency reference in many stabilized lasers. As part of the stabilization scheme an optical frequency dither is applied to the laser. In optical heterodyne experiments, this dither is transferred to the RF beat signal, reducing the spectral power density and hence the signal to noise ratio over that in the absence of dither. We removed the dither by mixing the raw beat signal with a dithered local oscillator signal. When the dither waveform is matched to that of the reference laser the output signal from the mixer is rendered dither free. Application of this method to a Winters iodine-stabilized helium-neon laser reduced the bandwidth of the beat signal from 6 MHz to 390 kHz, thereby lowering the detection threshold from 5 pW of laser power to 3 pW. In addition, a simple signal detection model is developed which predicts similar threshold reductions.

Lower studio dining room, Mooloomba House, Point Lookout, North Stradbroke Island

View through courtyard to lower studio dining room, as seen from upper living area.

Lower studio dining room, Mooloomba House, Point Lookout, North Stradbroke Island

View through courtyard to lower studio dining room, as seen from upper living area.

Lower studio dining room, Mooloomba House, Point Lookout, North Stradbroke Island

View through courtyard to lower studio dining room, as seen from upper living area.

Palynological reconnaissance of the Lower Carboniferous of Spitsbergen.

Microspores are described from three representative rock samples from the Billefjorden sandstones of the lower Carboniferous of central Vestspitsbergen. The age of this series is considered to range from Tournaisian to at least Visean and perhaps Namurian. One new genus, Velosporites, and thirteen new species are erected. Several species are shown to resemble previously described Russian, Canadian and Scottish types.

Lower Carboniferous microfloras of Spitsbergen, Part One

Describes and discusses the stratigraphic value of dispersed microspores from Culm localities, particularly from three of the most complete sections of the Billefjorden sandstones in the region. Two successive microfloral assemblages are distinguished. Correlations can be made locally and with various zones of Europe and North America. One new genus and many new species are represented in the microfloras.

Sections of some spores from the Lower Carboniferous of Spitsbergen

Sections of four lower Carboniferous dispersed-spore species, Labiadensites fimbriatus (Waltz) Hacquebard and Barss, Cristatisporites echinatus Playford, Camptozonotriletes velatus (Waltz) Playford, and Spinozonotriletes uncatus Hacquebard, are discussed and illustrated.

Lower Carboniferous microfloras of Spitsbergen, Part Two.

Second part (and conclusion) of a paper on dispersed microspores from Culm (Carboniferous) localities, mainly in Billefjorden sandstones. Macroscopic lithologic data for samples are appended. "The present study lends considerable support to the view . . . that terrestrial sequences of lower Carboniferous age may be subdivided precisely on the exclusive basis of their microspore content.

Delayed postural contraction of transversus abdominis in low back pain associated with movement of the lower limb

The temporal parameters of the response of the trunk muscles associated with movement of the lower limb were investigated in people with and without low back pain (LBP). The weight shift component of the task was completed voluntarily prior to a stimulus to move to allow investigation of the movement component of the response. In the control subjects the onset of electromyographic (EMG) activity of all trunk muscles preceded that of the muscle responsible for limb movement, thus contributing to the feed forward postural response. The EMG onset of transversus abdominis was delayed in the LBP subjects with movement in each direction, while the EMG onsets of rectus abdominis, erector spinae, and oblique abdominal muscles were delayed with specific movement directions. This result provides evidence of a change in the postural control of the trunk in people with LBP.

Behavior and interactions of children in cooperative groups in lower and middle elementary grades

The study investigated the behaviors and interactions of children in structured and unstructured groups as they worked together on a 6-week social studies activity each term for 3 school terms. Two hundred and twelve children in Grade 1 and 184 children in Grade 3 participated in the study. Stratified random assignment occurred so that each gender-balanced group consisted of 1 high-, 2 medium-, and 1 low-ability student. The results show that the children in the structured groups were consistently more cooperative and they provided more elaborated and nonelaborated help than did their peers in the unstructured groups. The children in the structured groups in Grade 3 obtained higher reading and learning outcome scores than their peers in the unstructured groups.