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51.
In this paper, we consider the manpower allocation problem with time windows, job-teaming constraints and a limited number of teams (m-MAPTWTC). Given a set of teams and a set of tasks, the problem is to assign to each team a sequential order of tasks to maximize the total number of assigned tasks. Both teams and tasks may be restricted by time windows outside which operation is not possible. Some tasks require cooperation between teams, and all teams cooperating must initiate execution simultaneously. We present an integer programming model for the problem, which is decomposed using Dantzig–Wolfe decomposition. The problem is solved by column generation in a branch-and-price framework. Simultaneous execution of tasks is enforced by the branching scheme. To test the efficiency of the proposed algorithm, 12 realistic test instances are introduced. The algorithm is able to find the optimal solution in 11 of the test instances. The main contribution of this article is the addition of synchronization between teams in an exact optimization context. 相似文献
52.
Anders Bruun Dimitrios Raptis Jesper Kjeldskov Mikael B. Skov 《Behaviour & Information Technology》2016,35(3):233-249
Coolness has recently started to be explored as a design goal for interactive products from practitioners as well as researchers within human–computer interaction (HCI), but there is still a need to further operationalise the concept and explore how we can measure it. Our contribution in this paper is the COOL questionnaire. We based the creation of the questionnaire on literature suggesting that perceived coolness is decomposed to outer cool (the style of a product) and inner cool (the personality characteristics assigned to it). In this paper, we focused on inner cool, and we identified 11 inner cool characteristics. These were used to create an initial pool of question items and 2236 participants were asked to assess 16 mobile devices. By performing exploratory and confirmatory factor analyses, we identified three factors that can measure the perceived inner coolness of interactive products: desirability, rebelliousness and usability. These factors and their underlying 16 question items comprise the COOL questionnaire. The whole process of creating the questionnaire is presented in detail in this paper and we conclude by discussing our work against related work on coolness and HCI. 相似文献
53.
Anders Wik 《Cryptologia》2016,40(3):215-220
All machines of type Enigma Z30, a model for encryption of numbers, were thought to have been destroyed. Three of these have been found in Stockholm. They were bought for commercial use around 1930. The machines and the background are described. 相似文献
54.
55.
Anders Wesslén 《Empirical Software Engineering》2000,5(2):93-123
The Personal Software Process (PSP) has during the last couple ofyears gained attention as a way to individual improvements insoftware development. The PSP is introduced to students and engineersthrough a course, which introduces a personal software developmentprocess. The personal software development process is improvedin steps during the course and a collection of methods is introducedto support the personal development process. The question is,however, how do these methods influence the performance of anindividual engineer? This question has been studied in a studymade at the Software Engineering Institute, and the study hasshown that the methods in the PSP have a positive effect on theperformance of the individuals. There is however a need to replicatethis study to confirm the findings in other settings and withother individuals. This paper describes a replicationof the study made at the Software Engineering Institute. Boththe original study and this replication are made on data reportedfrom the students taking the PSP course. The differences betweenthe two studies are the programming languages used, which heldthe courses, the class sizes, and the experiences of the students.In summary, the results from this replication confirm the resultsin the original study: Size estimation accuracy gets better,the defect density gets lower, the defects are found earlierand that the pre-compile yield gets better during the PSP course.Basically, the two studies show that the methods in the PSP helpengineers to improve their performance. 相似文献
56.
In this research we study the multi-product Economic Lot Scheduling Problem (ELSP) with manufacturing and remanufacturing opportunities. Manufacturing and remanufacturing operations are performed on the same production line. Both manufactured and remanufactured products have the same quality thus they fulfil the same demand stream. Tang and Teunter (2006) firstly studied this type of Economic Lot Scheduling Problem with Returns (ELSPR) and presented a complex algorithm for the optimal solution. More recently Teunter, Tang, and Kaparis (2009) proposed several heuristics to deal with the same problem using more computational efficient approaches. However, both studies have limited the attention to the common cycle policy with the assumption that a single (re)manufacturing lot is used for each item in each cycle. Relaxing the constraint of common cycle time and a single (re)manufacturing lot for each item in each cycle, we propose a simple, easy to implement algorithm, based on Segerstedt (1999), to solve the model using a basic period policy. Several numerical examples show the applicability of the algorithm and the cost savings. 相似文献
57.
Henrik Aanæs Anders Lindbjerg Dahl Kim Steenstrup Pedersen 《International Journal of Computer Vision》2012,97(1):18-35
Not all interest points are equally interesting. The most valuable interest points lead to optimal performance of the computer
vision method in which they are employed. But a measure of this kind will be dependent on the chosen vision application. We
propose a more general performance measure based on spatial invariance of interest points under changing acquisition parameters
by measuring the spatial recall rate. The scope of this paper is to investigate the performance of a number of existing well-established
interest point detection methods. Automatic performance evaluation of interest points is hard because the true correspondence
is generally unknown. We overcome this by providing an extensive data set with known spatial correspondence. The data is acquired
with a camera mounted on a 6-axis industrial robot providing very accurate camera positioning. Furthermore the scene is scanned
with a structured light scanner resulting in precise 3D surface information. In total 60 scenes are depicted ranging from
model houses, building material, fruit and vegetables, fabric, printed media and more. Each scene is depicted from 119 camera
positions and 19 individual LED illuminations are used for each position. The LED illumination provides the option for artificially
relighting the scene from a range of light directions. This data set has given us the ability to systematically evaluate the
performance of a number of interest point detectors. The highlights of the conclusions are that the fixed scale Harris corner
detector performs overall best followed by the Hessian based detectors and the difference of Gaussian (DoG). The methods based
on scale space features have an overall better performance than other methods especially when varying the distance to the
scene, where especially FAST corner detector, Edge Based Regions (EBR) and Intensity Based Regions (IBR) have a poor performance.
The performance of Maximally Stable Extremal Regions (MSER) is moderate. We observe a relatively large decline in performance
with both changes in viewpoint and light direction. Some of our observations support previous findings while others contradict
these findings. 相似文献
58.
We study stochastic stability of centralized Kalman filtering for linear time-varying systems equipped with wireless sensors. Transmission is over fading channels where variable channel gains are counteracted by power control to alleviate the effects of packet drops. We establish sufficient conditions for the expected value of the Kalman filter covariance matrix to be exponentially bounded in norm. The conditions obtained are then used to formulate stabilizing power control policies which minimize the total sensor power budget. In deriving the optimal power control laws, both statistical channel information and full channel information are considered. The effect of system instability on the power budget is also investigated for both these cases. 相似文献
59.
60.
Grammer Karl; Fink Bernhard; M?ller Anders P.; Manning John T. 《Canadian Metallurgical Quarterly》2005,131(5):658
Evolutionary behavioral biology suggests that certain characteristics of the human face and body are important for mate preferences and are therefore subject to sexual selection. J. Weeden and J. Sabini (see record 2005-11504-001) identify a number of weaknesses in the association between traits' attractiveness and health. In contrast, the authors argue that (a) studies on preferences for physical characteristics that rely on 1 trait permit only limited interpretation, (b) limitations placed on J. Weeden and J. Sabini's review exclude important associations, (c) there are misconceptions in their treatment of some traits, and (d) their selected literature provides an inaccurate picture regarding effect size. The authors suggest that future research in this field should seek conceptual and methodological constancy in trait selection and in the evaluation of attractiveness- and health-related traits. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献