Well distributed data can dramatically improve the efficiency and effectiveness of the use of distributed database systems to satisfy geographically dispersed data processing demands. Among several issues related to distribution design in distributed databases, data allocation design is of major importance. Choices of a fragmentation strategy and location of database files are two critical decisions. Thus far, solutions of these design problems, although interdependent, have been attempted separately. Solving both design problems simultaneously in a real design setting is not a trivial task. By formulating typical data allocation design problems, we can analyze the solution space and analytical properties of optimal data allocation design. Based on this, we suggest that clustering data elements into uniform fragments and then allocating these fragments is equivalent to solving the data allocation design as a whole. Such analytical examination of the data allocation design problem has not been attempted by other researchers, but it is essential to provide the theoretical foundation for solving the fragmentation design and fragment allocation design problem. We then extended the research by studying the effect on design issues of such characteristics of distributed processing as database access patterns, network scope, and design objectives. We also propose a generic taxonomy of data allocation design models. We further advance data allocation design skills in the following two directions. The first of these involves developing a design method that guarantees the minimum number of fragments to be considered as units of allocation. This improves upon existing fragment allocation methodologies, which are based on the assumed units of allocation. The second direction involves enhancements in modeling and solution procedures that allow efficient fragment allocation design. Concentration is on information processing environments, which have received little attention in the research literature. We first studied databases connected on local area networks under weak locality of reference. The model proposed is validated by simulation study. We then explored the multiple design objective optimization phase, which involves searching for models where several design objectives are in conflict. We addressed three important design objectives including response time, operating cost and data availability. In conclusion, we submit that the methodology proposed is likely to provide a better understanding of data allocation design problems, the solutions for which are expected to continue providing key design tools as advancing data communication techniques evolve.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The production of flight test plans have received attention from many research workers due to increasing complexity of testing facilities, the complex demands proposed by customers and the large volume of data required from test flights. The paper opens with a review of research work conducted by other authors who have contributed to ameliorating the preparation of flight test plans and processing the resulting data. This is followed by a description of a specific problem area; efficiently configuring the flight test data telemetry format (defined by the relevant standards while meeting user requirements of sampling rate and PCM word length). Following a description of a current semi-automated system, the authors propose an enhanced approach and demonstrate its efficiency through two case studies.

Multimodal container terminals are an important part of the logistics systems in international trade. Any improvement in the terminal efficiency is likely to reduce the costs of transporting goods, and to strengthen the trading position of the nation. During the import process, containers flow from ships to the storage yard for temporary storage and then are later moved to the hinterland by rail, or by road. The export process is the reverse of the import process. From the marshalling area, it is possible for a yard machine to carry an inbound container to the storage area and back with an inbound container in one round trip. This thesis investigates the inbound and outbound container process of multimodal container terminals in a multi-ship and multi-berth environment. The aim is to develop mathematical models and analytical tools for yard operation and planning. This study concerns the yardlayout, storage locations, operation strategies as well as the sequencing and scheduling of container process. Several models are developed for the scheduling of container process, taking account of planned and unplanned disruptions, and the intermediate buffer at the marshalling area. The problem is NP-hard and real-life problems often involve large number of containers. In addition, many schedules may not be feasible due to deadlock or violation of precedence-constraints. Good results were achieved on benchmark problems using the proposed innovative. In dealing with unplanned disruptions, reactive scheduling approach was found to give the results similar to as if the disruptions were planned in advance. Numerical investigations are also presented on various factors affecting the efficiency of seaport container terminals including the number of yard machines, and the number of quay crane. As with the various yard-layouts studied, it was found that containers are best stored in rows perpendicular to the quay-line with about 10 to 14 bays in each row. For a shorter ship service time, ideally the containers should be stored as close as possible to the ship. The best storage locations, however, are scarce resources and are not always available. Another model is developed for the best storage location as well as the best schedule for the container process. From an initial best schedule with predefined storage locations, the problem is solved by iterating through the refinement of storage scheme and re-scheduling. At a seaport terminal, ships are planned to arrive and leave within a scheduled time window. Nevertheless, a ship may arrive late due to poor weather conditions or disruptions at the previous port. Such delay may also affect its departure to the subsequent port. To minimise the impact of ship delays, port operators must consider alternate arrangements including re-assignment of berths, re-sequencing of ships and rescheduling of the container process. A ship delay model is developed and the problem is solved by combining branching and Tabu Search. The models developed in this thesis establish the relationship between significant factors and the options for increasing throughput by discovering the bottlenecks. The models are applicable as decision tools for operation planning, yard layout, and cost and benefit analysis for investment in infrastructures.

Garbage collector performance in LISP systems on custom hardware has been substantially improved by the adoption of lifetime-based garbage collection techniques. To date, however, successful lifetime-based garbage collectors have required special-purpose hardware, or at least privileged access to data structures maintained by the virtual memory system. I present here a lifetime-based garbage collector requiring no special-purpose hardware or virtual memory system support, and discuss its performance.

Cíle diplomové práce jsou popsat procesy probíhající v kontejnerovém přístavním terminálu, vytvořit přehled rozhodovacích problémů vznikajících v kontejnerovém přístavním terminálu z hlediska úrovně jejich typu řízení a plánování (strategické, taktické a operativní) a formulovat vybrané rozhodovací problémy a matematicky je analyzovat.

Electrical energy is one of the most common forms of energy these days. Consequently, electric power system is an indispensable part of any society. However, due to the deregulation of electricity markets and the growth in the share of power generation by uncontrollable renewable energies such as wind and solar, power system simulations are more challenging than earlier. Thus, new techniques for simplifying these simulations are needed. One important example of such simplification techniques is the power system reduction. Power system reduction can be used at least for four different purposes: a) Simplifying the power system simulations, b) Reducing the computational complexity, c) Compensating the data unavailability, and d) Reducing the existing uncertainty. Due to such reasons, power system reduction is an important and necessary subject, but a challenging task to do. Power system reduction is even more essential when system operators are facing very large-scale power systems and when the renewable energy resources like hydro, wind, and solar have a high share in power generation. This thesis focuses on the topic of large-scale power system reduction with high penetration of renewable energy resources and tries to pursue the following goals: • The thesis first reviews the different methods which can be used for simplifying the power system studies, including the power system reduction. A comparison among three important simplification techniques is also performed to reveal which simplification results in less error and more simulation time decrement. • Secondly, different steps and methods for power system reduction, including network aggregation and generation aggregation, are introduced, described and discussed. • Some improvements regarding the subject of power system reduction, i.e. on both network aggregation and generation aggregation, are developed. • Finally, power system reduction is applied to some power system problems and the results of these applications are evaluated. A general conclusion is that using power system simplification techniques and specially the system reduction can provides many important advantages in studying large-scale power systems with high share of renewable energy generations. In most of applications, not only the power system reduction highly reduces the complexity of the power system study under consideration, but it also results in small errors. Therefore, it can be used as an efficient method for dealing with current bulk power systems with huge amounts of renewable and distributed generations. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively. QC 20150116</p>