Stochastic single machine scheduling problem as a multi-stage dynamic random decision process

In this work, we study a stochastic single machine scheduling problem in which the features of learning effect on processing times, sequence-dependent setup times, and machine configuration selection are considered simultaneously. More precisely, the machine works under a set of configurations and requires stochastic sequence-dependent setup times to switch from one configuration to another. Also, the stochastic processing time of a job is a function of its position and the machine configuration. The objective is to find the sequence of jobs and choose a configuration to process each job to minimize the makespan. We first show that the proposed problem can be formulated through two-stage and multi-stage Stochastic Programming models, which are challenging from the computational point of view. Then, by looking at the problem as a multi-stage dynamic random decision process, a new deterministic approximation-based formulation is developed. The method first derives a mixed-integer non-linear model based on the concept of accessibility to all possible and available alternatives at each stage of the decision-making process. Then, to efficiently solve the problem, a new accessibility measure is defined to convert the model into the search of a shortest path throughout the stages. Extensive computational experiments are carried out on various sets of instances. We discuss and compare the results found by the resolution of plain stochastic models with those obtained by the deterministic approximation approach. Our approximation shows excellent performances both in terms of solution accuracy and computational time.

Investigation of New IPM Linear Machine Configuration with Low Permanent Magnet Used

Permanent magnet (PM) machines have received numerous attentions, since they are distinguished by many desirable features including simple construction and high efficiency. However, high price of the permanent magnet material may be considered as the main problems of such machines. Hence, the demand of PM machine with high efficient PM materials used is increased. In this study a new configuration of PM linear machine with high efficient PM material utilization, named as V-shape interior PM linear machine is investigated. The mentioned machine has been compared to the conventional I-shape counterpart. In order to perform sensible comparison, I-shape and V-shape machines have been designed with identical main design specifications. It has been observed that the V-shape topology shows better PM material utilization. It should be noted that about 43% higher efficient PM used is obtained by the V-shape machine compared to the conventional I-shape corresponding. It should be noted that the V-shape machine has been designed with about 51.6% less total permanent magnet volume compared to I-shape machine. Moreover, the introduced machine offers less cogging force as well as thrust force ripple than that of the conventional machine.

“Die Maschine als Symbol ihrer Wirkungsweise”: Wittgenstein, Reuleaux and Kinematics

In Philosophical Investigations 193–94, Wittgenstein draws a notorious analogy between the working of a machine and the application of a rule. According to the view of rule-following that Wittgenstein is criticizing, the future applications of a rule are completely determined by the rule itself, as the movements of the machine components are completely determined by the machine configuration. On what conception of the machine is such an analogy based? In this paper, I intend to show that Wittgenstein relied on quite a specific scientific tradition very active at the beginning of the twentieth century: the kinematic or the general science of machines. To explain the fundamental tenets of this line of research and its links with Wittgenstein, I focus on Franz Reuleaux (1829–1905), whose works were known to Wittgenstein. The first payoff of this investigation is to help distance the functionalist framework from which this passage is often read: Wittgenstein’s machines are not (or not primarily) computers. The second payoff is to explain why Wittgenstein talks about machines at this place in his discussion on rule-following: it is not the machine model in itself that is criticized in PI 193–94, but the “philosophical” temptation to generalize from it.

Development of a six-wheel drive vehicle: A comparative study on steering performance

The innovation for the recent agriculture tractors have been widely developed. These tractors are used to enhance the harvesting activities in way to lowering the labour cost. However, the current system of infield collection of oil palm fresh fruit bunches (FFB) by using mini-tractor-trailer (MTT) has its limitation. This MTT have poor traction on soft ground such as coastal and peat areas which give the limiting factors that prohibit the usage of any mini-tractor. Thus, the aim of this project is to fabricate a functioning prototype vehicle consist of two-wheel steering (2WS) and four-wheel steering (4WS) in measuring its performance of tractive effort and steering radius for usage in palm plantation. The machine configuration consists of main chassis, compartment to carry oil palm bunches, a mechanism for loading purposes, operator cabin, and associated hydraulic system. The laboratory test of performance evaluation were conducted to the developed vehicle. The results show that under 4WD mode, the turning radius of the vehicle was found to be 42.9% lesser if the 4WS mode is engaged. For 6WD with 4WS active, the turning radius was 46% lesser while turning for 42.2% lesser compared to 2WS. The slippage ranges are recorded between 8.5% to 22.5% where the slippage for the left wheel is negative as the left wheel rotates slower than the right wheel on the left turning of circular motion and vice versa. In addition, the vehicle design could be considered optimum as the measured tractive effort of the vehicle was found to be 32% of the vehicle gross weight. This is within the recommended tractive effort which is within a range of 30% to 36% of the suggested vehicle gross weight.

Notifications workflows using the CERN IT central messaging infrastructure

In the CERN IT agile infrastructure (AI), Puppet, the CERN IT central messaging infrastructure (MI) and the Roger application are the key constituents handling the configuration of the machines of the computer centre. The machine configuration at any given moment depends on its declared state in Roger and Puppet ensures the actual implementation of the desired configuration by running the Puppet agent on the machine at regular intervals, typically every 90 minutes. Sometimes it is preferable that the configuration change is propagated immediately to the targeted machine, ahead of the next scheduled Puppet agent run on this machine. The particular need of handling notifications in a highly scalable manner for a large scale infrastructure has been satisfied with the implementation of the CERNMegabus architecture, based on the ActiveMQ messaging system. The design and implementation of the CERN-Megabus architecture are introduced, followed by the implementation of the Roger notification workflow. The choice of ActiveMQ is analysed and the message flow between the Roger notification producer and the CASTOR, EOS, BATCH and Load Balancing consumers are presented. The employment of predefined consumer modules in order to speed up the on-boarding of new CERN-Megabus use cases is also described.

A novel energy efficient virtual machine configuration and migration technique

The recent growth in the data centre usage and the higher cost of managing virtual machines clearly demands focused research in reducing the cost of managing and migrating virtual machines. The cost of virtual machine management majorly includes the energy cost, thus the best available virtual machine management and migration techniques must have the lowest energy consumption. The management of virtual machine is solely dependent on the number of applications running on that virtual machine, where there is a very little scope for researchers to improve the energy. The second parameter is migration in order to balance the load, where a number of researches are been carried out to reduce the energy consumption. This work addresses the issue of energy consumption during virtual machine migration and proposes a novel virtual machine migration technique with improvement of energy consumption. The novel algorithm is been proposed in two enhancements as VM selection and VM migration, which demonstrates over 47% reduction in energy consumption.

Enhancing the production through SMED methodology

Aim of this experiment is to improve the production rate in steering pump manufacturing industry using single minute exchange of die method. Hydraulic steering pump manufacturer oftenface the problem of periodically changing the machine configuration which led to frequent delays. It was observed that most machines need the fixtures to be redesigned. Thus, comes to play the concept of single minute exchangeof Dies. It refers to single-digit time limit wherein every aspect of a setup change is completed in less than ten minutes. SMED is a changeover technique which is implementing to increase the output and decrease the quality losses due to changeovers. By examine the changeover process along with a stronger sense of teamwork and ownership leads to significant reduction in setup and change over times. Purpose of SMED is to find the workactually done and proper utilization of time during the changeover activity. Through the analysis, a better understanding was gained on how to do certain activities, when the line is running and also to determine the task that needs to be done to reduce the fine-tuning activities after the actual changeover. The faster the changeover time, the lesser is downtime of the machine. This project was focused on reducing the setup time based on the ideas of SMED.