Jobs arriving over time must be non-preemptively processed on one of m parallel machines, each of which running at its own speed, so as to minimize a weighted sum of the job completion times. In this on-line environment, the processing requirement and weight of a job are not known before the job arrives. The Weighted Shortest Processing Requirement (WSPR) on-line heuristic is a simple extension of the well known WSPT heuristic, which is optimal for the single machine problem without release dates. We prove that the WSPR heuristic is asymptotically optimal for all instances with bounded job processing requirements and weights. This implies that the WSPR algorithm generates a solution whose relative error approaches zero as the number of jobs increases. Our proof does not require any probabilistic assumption on the job parameters and relies extensively on properties of optimal solutions to a single machine relaxation of the problem. / Singapore-MIT Alliance (SMA)

Explanation-based Generalization requires that the learner obtain an explanation of why a precedent exemplifies a concept. It is, therefore, useless if the system fails to find this explanation. However, it is not necessary to give up and resort to purely empirical generalization methods. In fact, the system may already know almost everything it needs to explain the precedent. Learning by Failing to Explain is a method which is able to exploit current knowledge to prune complex precedents, isolating the mysterious parts of the precedent. The idea has two parts: the notion of partially analyzing a precedent to get rid of the parts which are already explainable, and the notion of re-analyzing old rules in terms of new ones, so that more general rules are obtained.

This thesis studies Production Scheduling in a multistage hybrid flowshop facility. It first states the general Production Planning and Scheduling problem and highlights some drawbacks of classical solutions. A theoretical decomposition-based approach is introduced whose main issue is to overcome non-efficient capacity utilization. By using Branch and Bound methods, an in-depth analysis of the scheduling part of the system is then carried out throughout the study and development of upper and lower bounds as well as branching schemes. Already-existing and new heuristics are presented and compared on different shop floor configurations. Five different heuristic approaches are studied. By scheduling the HFS one stage at a time the first approach uses different stage sequencing orders. The second and third approaches are mainly list heuristics. The second approach uses ideas derived from the multistage classical flowshop with a single machine per stage, while the third approach uses classical dispatching priority rules. The fourth and fifth approaches, respectively, use random scheduling and local search techniques. Statistical analysis is carried out in order to compare the heuristics and to select the best of them for each shop configuration. Already-existing and new lower bounds on the single stage subproblem are also presented and compared. Three new lower bounds are developed: a dual heuristic based bound, a partially preemptive bound and a heuristic for the so-called subset bound. Some of these lower bounds use a network flow algorithm. A new version of the “Preflow Push” algorithm which runs faster than the original one is presented. The best lower bounds are selected based on numerical tests. Two branch and bound algorithms are presented, an improved version of the sequence enumeration method and a generalization of the so-called interval branching method, along with several bounding strategies. Based on the upper and lower bound studies, several branch and bound algorithms are presented and compared using numerical tests on different shop floor configurations. Eventually, an Object Model for Scheduling Algorithm Implementations (OMSAI), that has been used for the computer implementation of the developed algorithms, is presented.

The mobility allowance shuttle transit (MAST) system is a hybrid transit system in which vehicles are allowed to deviate from a fixed route to serve flexible demand. A mixed integer programming (MIP) formulation for the static scheduling problem of a multi-vehicle Mobility Allowance Shuttle Transit (MAST) system is proposed in this thesis. Based on the MIP formulation, we analyze the impacts of time headways between consecutive transit vehicles on the performance of a two-vehicle MAST system. An analytical framework is then developed to model the performance of both one-vehicle and two-vehicle MAST systems, which is used to identify the critical demand level at which an increase of the fleet size from one to two vehicles would be appropriate. Finally, a sensitivity analysis is conducted to find out the impact of a key modeling parameter, w1, the weight of operations cost on the critical demand. In this paper, we develop an insertion heuristic for a multi-vehicle MAST system, which has never been addressed in the literature. The proposed heuristic is validated and evaluated by a set of simulations performed at different demand levels and with different control parameters. By comparing its performance versus the optimal solutions, the effectiveness of the heuristic is confirmed. Compared to its single-vehicle counterpart, the multiple-vehicle MAST prevails in terms of rejection rate, passenger waiting time and overall objective function, among other performance indices.

The death of a spouse is one of the most profound and life-altering events adults will ever experience. While the experience of spousal bereavement is traumatic at any time, there is evidence to support the fact that young women who are widowed experience unique challenges. The purpose of studying young widows was to understand the meaning of spousal bereavement for individual participants. The research tradition of phenomenology was chosen to inform the study, and the guiding question became what is the lived experience of spousal bereavement for young women? The study participants were five women who were under the age of 45 at the time of their husbands death. The experiences of these young widows were illuminated through stories and reflections on the journey of a young widow. Five themes emerged from their experiences. Young widows grieve both the loss of a companion and the death of their dreams. Accompanying these losses can be the challenges of single parenthood, the need for career, financial and lifestyle changes, and the readjustment to life as a single adult. Increased understanding from the perspective of the bereaved widow, along with strategies and interventions for nurses working with this group of women, will provide nurses and health care professionals with skills to better assist this client population.

Socrates teaches in the Meno that in order for a belief to be justified, an appropriate relation must ‘tie down’ the belief to its (apparent) truth. Alvin Goldman’s position of externalism holds that for a belief to be justified, an appropriately reliable process must have obtained. One need not be aware of this reliable process. Conversely, Laurence BonJour’s brand of internalism holds that this relation between a belief and its (apparent) truth is just what the cognizer needs to be aware of in order for that belief to be justified. This work examines their debate, with particular interest paid to BonJour’s case of Norman: a clairvoyant who forms a belief via this ability but has no evidence for or against the belief or his own clairvoyance. Using this case, I propose an ‘epistemological spectrum’ wherein the insight of externalism is appreciated – what Robert Brandom deems the Founding Insight of Reliabilism – that a reliably produced belief bears some epistemic legitimacy, while retaining the insight of internalism: that objective reliability cannot offset subjective irrationality. This is done by classifying cases wherein only the obtainment of a reliable process occurs as epistemically rational, though not justified. Ultimately I reconcile the virtues of both positions, and propose that Goldman’s brand of full blooded externalism was generated by following an intuitional illusion by way of affirming the consequent.

There are a several methods to evaluate usability of systems with graphical user interfaces (GUIS). However, effective methods for evaluating non-GUI interaction devices in the domain of Interactive Television are presently not available. This thesis presents a modified Heuristic Evaluation method for rapid inspection of non-GUI TV-interaction devices such as remote controls. Additionally, to enable the evaluators to more easily think from a user perspective when performing the evaluation, the persona method was also evaluated for use in this domain. The modified Heuristic Evaluation method was evaluated in an actual development project where engineers applied the method on remote control prototypes. The result suggests that the method can be used effectively by engineers and that it identifies usability problems appropriately. The persona approach seemed to provide little support to the engineers in terms of evaluating this type product.

Snow cleaning is one of the important tasks in the winter time in Sweden. Every year government spends huge amount money for snow cleaning purpose. In this thesis we generate a shortest road network of the city and put the depots in different place of the city for snow cleaning. We generate shortest road network using minimum spanning tree algorithm and find the depots position using greedy heuristic. When snow is falling, vehicles start work from the depots and clean the snow all the road network of the city. We generate two types of model. Models are economic model and efficient model. Economic model provide good economical solution of the problem and it use less number of vehicles. Efficient model generate good efficient solution and it take less amount of time to clean the entire road network.

This thesis aims to produce a novel multi-objective algorithm that is based on Cuckoo Search by Dr. Xin-She Yang. Cuckoo Search is a promising nature-inspired meta-heuristic optimization algorithm, which currently is only able to solve single-objective optimization problems. After an introduction, a number of theoretical points are presented as a basis for the decision of which algorithms to hybridize Cuckoo Search with. These are then reviewed in detail and verified against current benchmark algorithms to evaluate their efficiency. To test the proposed algorithm in a new setting, a real-world combinatorial problem is used. The proposed algorithm is then used as an optimization engine for a simulation-based system and compared against a current implementation.

Socrates teaches in the Meno that in order for a belief to be justified, an appropriate relation must ‘tie down’ the belief to its (apparent) truth. Alvin Goldman’s position of externalism holds that for a belief to be justified, an appropriately reliable process must have obtained. One need not be aware of this reliable process. Conversely, Laurence BonJour’s brand of internalism holds that this relation between a belief and its (apparent) truth is just what the cognizer needs to be aware of in order for that belief to be justified. This work examines their debate, with particular interest paid to BonJour’s case of Norman: a clairvoyant who forms a belief via this ability but has no evidence for or against the belief or his own clairvoyance. Using this case, I propose an ‘epistemological spectrum’ wherein the insight of externalism is appreciated – what Robert Brandom deems the Founding Insight of Reliabilism – that a reliably produced belief bears some epistemic legitimacy, while retaining the insight of internalism: that objective reliability cannot offset subjective irrationality. This is done by classifying cases wherein only the obtainment of a reliable process occurs as epistemically rational, though not justified. Ultimately I reconcile the virtues of both positions, and propose that Goldman’s brand of full blooded externalism was generated by following an intuitional illusion by way of affirming the consequent.