Hybrid Make-To-Stock (MTS)-Make-To-Order (MTO) manufacturing is a well known policy that captures the benefits of both MTS and MTO policies. This manufacturing policy is adopted by many manufacturing firms because it allows for production based on customer specifications while keeping short response times. We study a hybrid MTS-MTO manufacturing system which consists of two processing stages and an intermediate buffer between these two stages. We propose two separate scenarios for ordering and replenishment of components from the first stage which will give more realistic guidance for practitioners. The first scenario is batching customer orders before being released to the first stage. The second scenario is batch replenishment of common components from the first stage. Most existing MTS-MTO models focus on one-for-one ordering and replenishment strategies. We enhance these models by introducing a batch ordering policy to account for economies of scale in ordering when there is an ordering cost associated with each order placed for common components. We use queueing theory to model the system behavior and use the matrix-geometric method to evaluate system performance under the new ordering policy. Afterwards, we develop an optimization model with the objective to minimize the system overall costs. The purpose of our optimization model is to find the optimal intermediate buffer size and the optimal order quantity for the system. In the second scenario, we introduce the batch replenishment policy from stage 1. This policy is suitable when stage 1 and stage 2 are physically distant and there is a shipping cost incurred when components are transferred from stage 1 to stage 2. The decision variables in this model are the intermediate buffer size and the shipping quantity. We show that the base stock policy is sub-optimal when there is an ordering cost incurred for ordering components. The savings from adopting the batch ordering policy are high and the response time for most customer orders is not affected. When there are shipping costs and shipping time between the two stages, we show that the right selection of the system decision variables can have a large impact on the total cost incurred by the system.

With the advent of Flash based solid state devices (SSDs), the differences in physical devices used to store data in computers are becoming more and more pronounced. Effectively mapping the differences in storage devices to the files, and applications using the devices, is the problem addressed in this dissertation. This dissertation presents the Umbrella File System (UmbrellaFS), a layered file system designed to effectively map file and device level differences, while maintaining a single coherent directory structure for users. Particular files are directed to appropriate underlying file systems by intercepting system calls connecting the Virtual File System (VFS) to the underlying file systems. Files are evaluated by a policy module that can examine both filenames and file metadata to make decisions about final placement. Files are transparently directed to and moved between appropriate file systems based on their characteristics. A prototype of UmbrellaFS is implemented as a loadable kernel module in the 2.4 and 2.6 Linux kernels. In addition to providing the ability to direct files to file systems, UmbrellaFS enables different decisions at other layers of the storage stack. In particular, alternate page cache writeback methods are presented through the use of UmbrellaFS. A multiple queue strategy based on file sequentiality and a sorting strategy are presented as alternatives to standard Linux cache writeback protocols. These strategies are implemented in a 2.6 Linux kernel and show improvements in a variety of benchmarks and tests.

The molecular magnet [FeII(£G)FeII(£N)(ox)2(Phen)2]n, whose chemical formula is C28H16Fe2N4O8 for unity, has been studied by magnetization measurements, neutron diffraction, and field-dependent specific heat. From the magnetization measurements, the quasi-ferrimagnetic behavior at T>Tm region can be well described with alternating Land&#x00E9; factors within 1D Ising chain model. However, in T<Tm region, the construction of long-range magnetic ordering due to the increase of interchain interaction was investigated, which is consistent with the anomaly shown in the low temperature specific heat measurement. Furthermore, an intrinsic antiferromagnetic configuration is deduced from analyzing Bragg pattern of neutron scattering. In specific heat measurement, a £f-type anomaly indicating the long-range magnetic ordering was observed. In addition, the magnetic entropy due to this anomaly is much smaller than expected value indicating the spin fluctuated as short-range ordering at T>Tm.

The aim of the study, which was carried out in two main parts, was to investigate the atomic and magnetic ordering in various full Heusler alloy systems.In the theoretical part of the thesis, investigations based on the statiscothermodynamical theory of ordering by means of Bragg-Williams-Gorsky (BWG) method combined with electronic theory in the pseudopotential approximation have been conducted to model order-order (L21&amp / #8596 / B2) and order-disorder (B2&amp / #8596 / A2) phase transformations in Ni-Mn-C (C=Ga, In, Sb) and A2BGa (A=Fe, Ni, Co / B=Ni, Mn, Co, Fe) Heusler alloys. The partial ordering energies, calculated according to the electronic theory of alloys in pseudopotential approximation for the first two coordination spheres were utilized as input data for the theoretical superlattice formation models based on BWG approximation. Furthermore, the trends of L21&amp / #8596 / B2 transition temperatures with electron concentration at A, B and C atomic sites were determined. In the experimental part of the thesis, structural and magnetic properties of Ni-Mn-Ga and Ni-Mn-Al Heusler alloys were investigated. For the Ni-Mn-Ga Heusler alloy system, it was found that the martensitic (TM) and Curie temperatures (TC) merge for Ni54Mn20Ga26 and Ni56Mn18Ga26 alloys by compositional tuning. For the Ni-Mn-Al Heusler alloy system, it was found that ferromagnetism was introduced into these alloys by low temperature aging, as a result of the stabilization of the L21 phase. In addition to that, magnetocaloric effect (MCE) was determined in the vicinity of the first order magneto-structural transition for Ni-rich Ni-Mn-Ga alloys and near the second order magnetic transition for the Ni2MnAl alloy.

In this thesis, we present an event orderer application that works on Turkish texts. Events are words denoting an occurrence or happenings in natural language texts. By using the features of the events in a sentence or by the helps of temporal expressions in the sentence, anchoring an event on a timeline or ordering events between other events are called event ordering. The application presented in this thesis, is one of the earliest study in this domain with Turkish and it realizes all needed sub modules for event ordering. It realizes event recognition in Turkish texts and event feature detection in Turkish texts. In addition to this, the application is realizing temporal expression recognition and temporal signal recognition tasks.

In this dissertation, we consider a multi-item two-echelon inventory distribution system in which the central warehouse operates with (Q, R) policy, and each local warehouse implements base-stock policy. The objective is to find the policy parameters minimizing the relevant system-wide costs subject to an aggregate mean response time constraint at each facility. We first propose an exact solution procedure based on a branch-and-price algorithm to find the relevant policy parameters of the system considered. Then, we propose four alternative heuristics to find the optimal or near-optimal policy parameters of large practical-size systems. The first heuristic, which we call the Lagrangian heuristic, is based on the simultaneous approach and relies on the integration of a column generation method and a greedy algorithm. The other three heuristics are based on the sequential approach, in which first the order quantities are determined using a batch size heuristic, then the reorder levels at the central warehouse and the basestock levels at the local warehouses are determined through the same method used for the Lagrangian heuristic. We also propose a lower bound for the system-wide cost. Later, we extend our study to compound Poisson demand. The performance of the Lagrangian heuristic is found to be extremely well and improves even further as the number of parts increases. Also the computational requirement of the heuristic is quite tolerable. This makes the heuristic very promising for large practical industry-size problems. The performance of the sequential heuristics is also satisfactory, but not as much as the Lagrangian heuristic.

Nanostructured materials have potential technological applications due to their characteristic dimensions. The material performance will depend on the atomic structure, and composition of these materials. This thesis focuses on proposing a reliable method for fabricating nanoporous alumina and palladium nanoparticles inside the templates.Palladium nanoparticles were synthesized in commercial porous alumina templates using electrodeposition. Pores within these nanoporous membranes act as templates for the synthesis of nanostructures of the desired material. Electrodeposition is achieved using a three-terminal set-up and a potentiostat. Different types of deposition techniques were investigated to improve the distribution of the deposit. The nanoparticles were characterized by SEM/EDX for composition. The commercial templates have high aspect ratio, but are not hexagonally ordered. Hence porous alumina was fabricated in the laboratory by anodization of aluminum.

Ordering and sales control information system (IS), which is being introduced in the trading company „Egzotika“ Lipeikis enterprise. The firm is operating in wholesale and retail business of tires and wheel rims. Due to the growth of the company, increased number of selling locations, and constantly growing and changing market environment, it became crucial to optimize the work of various departments in the company. The new IS will eliminate the repetition of the tasks performed and will guarantee rapid exchange of the important information during the working day. The purpose of the new IS is to improve the control of ordering and sales. The new IS will supplement the existing corporate accounting IS, because it can’t solve the problems of ordering and sales control. The new IS allows to perform these tasks: The formation of the orders - Ability to work with data on stocks in the warehouses - The optimization of the flow of goods within the departments - Sales analysis Initial information is imported to new IS from the corporate accounting IS. The new IS is operating with Microsoft Access 2002 and Microsoft Visual Basic programs. The module of the importation of the data from corporate accounting IS to new IS is actualized using CA-Clipper 5.2e programming language.

The main objective of this work was to develop and implement the travel reservation system, which would be easy to use, widely accessible for large amount of users, progressive and works without mistakes. This system would allow users to save time planning job or holiday trip. The project was implemented using PHP and Microsoft SQL. The program performs a lot of functions: booking of tickets, hotels and additional services, travel routes catalog review and personal trip design, edition of the reservations that has been already made. These are only several features from the travel reservation system, which would help to plan holiday or job trip.

In our daily life, we often experience waiting in a queue to receive some kind of service. Some customers do not join the queue at the end like other normal customers, and try to cut in the queue hoping to have a shorter waiting time and a higher level of satisfaction. This behaviour is called customer interjection. Some of these customers only try to cut in queue, while some others try to find excuses for interjection. For instance, the first-come-first-served (FCFS) service discipline is usually assumed in public places like restaurants, banks, airports, and supermarkets. However, customer interjections can still be seen in these places. In telecommunications networks, to test the efficiency of transmission, artificial packages are inserted into the normal traffic in a random manner. These interjections can affect the waiting time of other customers in queue. Such interjections may reduce the waiting time of interjecting customers, but increase the waiting time and dissatisfaction of others. In this work, an M/M/1 queueing system with customer interjection is investigated. The arrival of customers to the system is assumed to be a Poisson process with arrival rate . The service times for customers are independent and identically distributed random variables with an exponential distribution with rate . Customers are dispersed into normal customers and interjecting customers. A normal customer joins the queue at the end, and an interjecting customer tries to cut in the queue and occupy a position as close to the head of the queue as possible. Two parameters are introduced to describe the interjection behaviour: the percentage of customers interjecting and the tolerance level of interjection by individual customers who are already waiting in the queue. Using matrix-analytic methods and stochastic comparison methods, the waiting times of normal customers and interjecting customers are being studied. The impacts of the two parameters on the waiting times are analyzed in detail, and the implications of the results are discussed with numerical examples. It is found that the waiting times are sensitive to the tolerance level of interjection by individual customers. It is also found that eliminating customer interjection would be always beneficial to normal customers and arbitrary customers though it would not always be so for interjecting customers.