Assigning multiple activities to work shifts

In some companies such as large retail stores, the employees perform different activities (e.g., cashier or clerk in a specific department) to respond to a customer demand for each activity that varies over the planning horizon and must be fulfilled as soon as possible. For a given time period, this demand translates into an ideal number of employees required for the corresponding activity. During a work shift, an employee can be assigned to several activities that are interruptible at any time and subject to operational constraints (required skills, minimum and maximum assignment durations). Given work shifts already assigned to the employees, the multi-activity assignment problem (MAAP) consists of assigning activities to the shifts such that the activity demands are satisfied as best as possible over the planning horizon. In this paper, we propose three integer programming models for the MAAP and develop various heuristics based on mathematical programming techniques. Computational results obtained on randomly generated MAAP instances show that a heuristic column generation method embedded into a rolling horizon procedure provides the best results in general.     

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Registration and real-time visualization of transcranial magnetic stimulation with 3-D MR images

This paper describes a method for registering and visualizing in real-time the results of transcranial magnetic stimulations (TMS) in physical space on the corresponding anatomical locations in MR images of the brain. The method proceeds in three main steps. First, the patient scalp is digitized in physical space with a magnetic-field digitizer, following a specific digitization pattern. Second, a registration process minimizes the mean square distance between those points and a segmented scalp surface extracted from the magnetic resonance image. Following this registration, the physician can follow the change in coil position in real-time through the visualization interface and adjust the coil position to the desired anatomical location. Third, amplitude of motor evoked potentials can be projected onto the segmented brain in order to create functional brain maps. The registration has subpixel accuracy in a study with simulated data, while we obtain a point to surface root-mean-square error of 1.17+/-0.38 mm in a 24 subject study.     

People-to-People-to-Geographical-Places: The P3 Framework for Location-Based Community Systems

In this paper we examine an emerging class of systems that link People-to-People-to-Geographical-Places; we call these P3-Systems. Through analyzing the literature, we have identified four major P3-System design techniques: People-Centered systems that use either absolute user location (e.g. Active Badge) or user proximity (e.g. Hocman) and Place-Centered systems based on either a representation of peoples use of physical spaces (e.g. ActiveMap) or on a matching virtual space that enables online interaction linked to physical location (e.g. Geonotes). In addition, each feature can be instantiated synchronously or asynchronously. The P3-System framework organizes existing systems into meaningful categories and structures the design space for an interesting new class of potentially context-aware systems. Our discussion of the framework suggests new ways of understanding and addressing the privacy concerns associated with location aware community system and outlines additional socio-technical challenges and opportunities.     

Hirsch index or Hirsch rate? Some thoughts arising from Liang’s data

Hirsch’s h-index gives a single number that in some sense summarizes an author’s research output and its impact. Since an individual author’s h-index will be time-dependent, we propose instead the h-rate which, according to theory, is (almost) constant. We re-analyse a previously published data set (Liang, 2006) which, although not of the precise form to properly test our model, reveals that in many cases we do not have a constant h-rate. On the other hand this then suggests ways in which deeper scientometric investigations could be carried out. This work should be viewed as complementary to that of Liang (2006).     

Iron compounds electrodeposited onto a transparent semiconductor: Synthesis and characterisation by UV-vis spectroscopy

Homogeneous thin layers of lepidocrocite, green rust incorporating chloride anions (GRCl-GR1) and green rust incorporating sulphate anions (GRSO₄-GR2) were successfully electrodeposited onto tin dioxide substrate (SnO₂). The UV-vis spectroscopy absorbance, measured just after synthesis, increases linearly with the amount of iron compounds confirming that the electrodeposition is a homogeneous process. From the spectra, the absorption coefficients were determined for the three compounds. The monitoring by UV-vis spectroscopy measurements in real time of the oxidation in the air of the two unstable compounds, GRCl and GRSO₄, shows that the two green rusts have a different behaviour due to their own structure. The presence of an isobestic point in the case of GRSO₄ translates one equilibrium with its oxidised compound. This phenomenon is not observed for GRCl, however, the characteristic variation of the absorbance in the high wavelengths gives information on its oxidation reaction. From simple measurements, fruitful information on green rusts is obtained and this experimental system may be applied to other unstable solid compounds.     

Response of montane meadow vegetation after two years of streamflow augmentation

Changes in montane meadow vegetation were examined in a previously ephemeral drainage that received flow augmentation as a mitigation measure for a transbasin diversion in southeastern Wyoming. After two years of elevated surface and groundwater levels, the herbaceous vegetation shifted toward more water-tolerant species. Dry meadows became like moist meadows, moist meadows became more like moist-wet meadows, and moist-wet meadows became more like wet meadows. Sedge (Carex spp.) biomass increased from 337 to 456 g m^?2 in the wet meadows, while tufted hairgrass (Deschampsia cespitosa) biomass decreased from 18 to 3 g m^?2 in the moist-wet meadows. Slimstem reedgrass (Calamagrostis neglecta) remained unchanged in the meadows with shallow standing water, but increased from 17 to 88 stems m^?2 in the dry meadows with an elevated water table. Bare ground also increased as much as 31 per cent in the meadows without a defined drainage channel.     

城市滨水区设计——澳大利亚两城市“南岸区”的评介（续前）

有针对性地对澳大利亚2个主要城市--墨尔本(Melbourne)和布里斯班(Brisbane)市内的滨河文化休闲区城市设计进行了深入分析,这2个区域在两城市都被称作"南岸(Southbank)".通过观测这2个区域中广泛的休闲活动,对滨水区的利用、尺度规模和连通性(connectivity)等单一的功能规划问题进行了评价,并考察了这些因素究竟怎样与更复杂的系统性、行为性、表现性结果相关联.研究了城市沿河区域休闲体验的4个