Sliding elastic lattice: an explanation of the motion of superconducting vortices

We introduce a system where an elastic lattice of particles is moved slowly at a constant velocity under the influence of a local external potential, construct a rigid-body model through simplification processes, and show that the two systems produce similar results. Then, we apply our model to a superconducting vortex system and produce path patterns similar to the ones reported in [Lee et al., Phys. Rev. B 84, 060515 (2011)] suggesting that the reasoning of the simplification processes in this paper can be a possible explanation of the experimentally observed phenomenon.Comment: 5 pages, 3 figures, Submitted to Physical Review Letters; Reference [17] Lee et al., Phys. Rev. B Accepted changed to Lee et al., Phys. Rev. B 84, 060515 (2011

An XML Representation of the Parametric Data Model for Temporal Data

This paper introduces an XML representation for the parametric data model handling temporal data. The parametric data model represents an object either in a single tuple or in multiple tuples. This feature reduces query complexities at the user level and provides elegant approaches to manage temporal data. However, this property requires the data model to have flexible attribute value sizes and causes the implementation complexity despite its advantages. To solve this problem, parametric databases have to manage variable attribute value sizes, which are in the same attribute field. XML can provide a feasible solution to represent parametric databases. XML does not have any boundary restrictions. In this paper, we introduce an XML representation scheme for the parametric data model and show that the scheme reflects the properties in the parametric data model

BANKRUPTCY REORGANIZATION: LEGAL DYNAMICS ASSOCIATED WITH ECONOMIC DISCONTINUITY

This thesis attempts to discover the factors leading to such failures and to propose a cure. It argues that the basic structure of Chapter 11 of the Code, the debtor in possession structure, is one of the essential factors causing such a high rate of failure. The thesis further asserts that it is possible to reduce the rate of unsuccessful reorganization if the bankruptcy court exercises its power of case management more actively and expeditiously. For example, the court can screen the debtors\u27 filing for relief before the reorganization case proceeds too far. Chapter II of this thesis examines the basic structure of Chapter 11 of the Code, the debtor in possession construct, to discover the factors leading cases to failure. This chapter argues that most of the failing cases have resulted from problems connected to the debtor in possession structure. In the ordinary course of events in most Chapter 11 cases, while the debtor continues to operate its business and manage its property as an entity known as the debtor in possession, its creditors suffer, for example, a lack of necessary information about the debtor\u27s financial conditions. Moreover, they are often apathetic to the reorganization of the debtor because of, in part, the relatively high cost of participation compared to their claims. Under Chapter 11, the debtor in possession not only exercises its wide discretion in operating the business but also enjoys the exclusive right to propose a plan for at least 120 days. As a result, the debtor in possession has many incentives to take advantage of the process, such as abuses of the automatic stay and other strategies delaying the process. That, to some extent, explains why so many businesses filing for reorganization relief fail to reorganize or fail to survive the financial difficulties even after the plan has been confirmed. Chapter III discusses the provisions restricting such discretion of the debtor in possession. Under the Code, there are several institutional devices restricting the debtor in possession\u27s seemingly absolute discretion. Among the restricting methods, Chapter III deals mainly with the mandatory creditors\u27 committee and the fiduciary duties of the debtor in possession. Other restricting methods will be discussed in detail in the following chapters

A parametric prototype for spatiotemporal databases

The main goal of this project is to design and implement the parametric database (ParaDB). Conceptually, ParaDB consists of the parametric data model (ParaDM) and the parametric structured query language (ParaSQL). Parametric data model is a data model for multi-dimensional databases such as temporal, spatial, spatiotemporal, or multi-level secure databases. Main difference compared to the classical relational data model is that ParaDM models an object as a single tuple, and an attribute is defined as a function from parametric elements. The set of parametric elements is closed under union, intersection, and complementation. These operations are counterparts of or, and, and not in a natural language like English. Therefore, the closure properties provide very flexible ways to query on objects without introducing additional self-join operations which are frequently required in other multi-dimensional database models

Literature Review on Temporal, Spatial, and Spatiotermpoal Data Models

This paper reviews papers on temporal databases, spatial databases, and spatio-temporal databases

Information flow in an atmospheric model and data assimilation

Weather forecasting consists of two processes, model integration and analysis (data assimilation). During the model integration, the state estimate produced by the analysis evolves to the next cycle time according to the atmospheric model to become the background estimate. The analysis then produces a new state estimate by combining the background state estimate with new observations, and the cycle repeats. In an ensemble Kalman filter, the probability distribution of the state estimate is represented by an ensemble of sample states, and the covariance matrix is calculated using the ensemble of sample states. We perform numerical experiments on toy atmospheric models introduced by Lorenz in 2005 to study the information flow in an atmospheric model in conjunction with ensemble Kalman filtering for data assimilation. This dissertation consists of two parts. The first part of this dissertation is about the propagation of information and the use of localization in ensemble Kalman filtering. If we can perform data assimilation locally by considering the observations and the state variables only near each grid point, then we can reduce the number of ensemble members necessary to cover the probability distribution of the state estimate, reducing the computational cost for the data assimilation and the model integration. Several localized versions of the ensemble Kalman filter have been proposed. Although tests applying such schemes have proven them to be extremely promising, a full basic understanding of the rationale and limitations of localization is currently lacking. We address these issues and elucidate the role played by chaotic wave dynamics in the propagation of information and the resulting impact on forecasts. The second part of this dissertation is about ensemble regional data assimilation using joint states. Assuming that we have a global model and a regional model of higher accuracy defined in a subregion inside the global region, we propose a data assimilation scheme that produces the analyses for the global and the regional model simultaneously, considering forecast information from both models. We show that our new data assimilation scheme produces better results both in the subregion and the global region than the data assimilation scheme that produces the analyses for the global and the regional model separately

An XML-based implementation of the parametric model for ad-hoc query of temporal and spatiotemporal data

The parametric model is one of the data models for dimensional data. Values in the parametric model are defined as functions. Such modeling concept helps one achieve a one-to-one correspondence between objects in the real world and records in a database. One of the important requirements is that domains of values should be closed under the set theoretic operations such as union, intersection, and complementation. Because of this, ParaSQL, a query language of the parametric model, is able to mimic natural languages more closely. In this dissertation we validate and implement the parametric model for temporal and spatiotemporal data. We also develop a preliminary prototype for the users of NC-94, an interesting dataset in agriculture;Viewing values as functions leads variable-length tuples. Potentially, such values vary in size ranging from a few bytes to gigabytes and beyond. This makes implementation of the parametric model a challenging problem. To meet the challenge, we develop an XML-based storage and deploy it in our implementation. Incidentally, XML is also used for interfacing various modules and artifacts like parse tree, expression tree, and iterators to fetch data from a disk;The NC-94 dataset, mentioned above, contains the most complete record of spatiotemporal variables that characterize the dynamics of agriculture covering the north central region in the United States. To support ad-hoc query of data in its geospatial context, a novel hybrid structure is designed and implemented. We use GML to describe geospatial information. Use of GML is a good match, because it is XML-based. More importantly, it meets the set theoretic closure requirements proposed by the parametric model;Validation and implementation methodologies introduced in this dissertation will contribute to database and GIS communities. The validation demonstrates the ease of use and efficiency of the parametric model for temporal and spatiotemporal data. This should help settle a debate in temporal database community which has continued since the mid 1980s. The findings also extend to spatial and spatiotemporal data. It is an important baby-step toward full-fledged implementation of the parametric model. We hope that this work will also help bring database and GIS communities together

XPDec: an XML plagiarism detection system for procedural programming languages

Plagiarisms are frequently occurring in the Computer Science courses, especially in computer programming. In this thesis, XML plagiarism detection model is introduced and XML is used as an intermediate data exchange mechanism in the suggested model. Since a procedural programming language is defined by its specific rules and it is well-structured form, we can generate an XML document from a program source based on the XML schema. As long as we can generate XML documents from given program sources, XML queries to extract information how they are similar to each other can be queried over the documents. This idea makes us encourage to moving our attention to plagiarism detection models. As the result of this study, XML Plagiarism Detection System (XPDec) has been developed. The plagiarism detection systems for programming can be classified into two main groups: attribute-counting based systems and structural metrics based systems. XPDec system uses the combined detection mechanism. In addition to the mechanism, XPDec system is adopting the XML query language suggested in XML plagiarism detection model to extract control sequences from XML documents. This mechanism increases the accuracy of the results. At the end of this thesis we shows that the XPDec system gives high accuracy results to finding similarities among the given source programs