Comprehension and transformation of object-oriented models

During object-oriented (OO) software development, the problem domain is mapped into the solution space implemented by a programming language and executed by a computer system. During OO design, the real-world objects are mapped into software objects with assigned responsibilities to fulfill certain tasks. In order to improve the quality of software systems, a number of approaches have been proposed to improve the quality of the existing code. One of these is "restructuring", a process of improving the internal structure of a software system without altering its external behaviour. However, refining implements artifacts tends to be much more expensive than refining design artifacts. In addition, Model Driven Architecture (MDA) with its supporting tools has become the mainstream in software development and provides increasingly powerful facilities to automatically generate documentation and code from the platform-independent design model. These facts make the quality of a software product greatly associated with the quality of the design model. In recent years, there is a trend of addressing restructuring at a higher level of abstraction. In MDA, the Unified Modeling Language (UML) model is widely used to build and visualize the design in a platform-independent way. In this dissertation, we propose the development of approaches to obtain comprehension, and perform restructuring of the UML design model

The difference of value of cash between financially constrained and unconstrained firms

Corporate cash holding，value of cash and financial constraints are always topical issues in academic studies. Since the cash holdings are so important for the operation and investment of companies, companies can allocate appropriate funds to support the operations and conduct profitable investments only with a good level of cash holding. In addition, holding sufficient internal funds can help firms to over the hump in future. This study investigates several measures, which are used for measuring the financial constraints. Besides, the impaction of cash holdings to firms under the circumstances of both financially constrained and unconstrained are discussed. On the purpose of classifying companies as constrained and unconstrained, we use four kinds of proxies, which are annual payout ratio, firm size, debt rating (long-term) and paper rating (short-term). The samples I use in this study include the data of firms in US market, which is available on Compustat's database over the period of 2000–2014. Through conducting the random effect model and GMM model, we find that financially constrained firms usually retain more cash than financially unconstrained firms and the impact of the cash is bigger for financially constrained firms. Furthermore, the firms without external fund resource will create more value with every extra dollar reserved and increase their marginal value of cash

Quantum interferometers: principles and applications

Interference, which refers to the phenomenon associated with the superposition of waves, has played a crucial role in the advancement of physics and finds a wide range of applications in physical and engineering measurements. Interferometers are experimental setups designed to observe and manipulate interference. With the development of technology, many quantum interferometers have been discovered and have become cornerstone tools in the field of quantum physics. Quantum interferometers not only explore the nature of the quantum world but also have extensive applications in quantum information technology, such as quantum communication, quantum computing, and quantum measurement. In this review, we analyze and summarize three typical quantum interferometers: the Hong-Ou-Mandel (HOM) interferometer, the N00N state interferometer, and the Franson interferometer. We focus on the principles and applications of these three interferometers. In the principles section, we present the theoretical models for these interferometers, including single-mode theory and multi-mode theory. In the applications section, we review the applications of these interferometers in quantum communication, computation, and measurement. We hope that this review article will promote the development of quantum interference in both fundamental science and practical engineering applications.Comment: 64 pages, 40 figures. Comments are welcom

Quantitative analysis of the genes affecting development of the hypopharyngeal gland in honey bees (Apis mellifera L.)

Royal jelly has many important biological functions, however the molecular mechanism of royal jelly secretion in hypopharyngeal gland (HG) is still not well understood. In our previously study, six genes (SV2C, eIF-4E, PDK1, IMP, cell growth-regulating nucleolar protein and TGF-βR1) have been shown to might be associated with royal jelly secretion. In this study, the relative expression levels of these genes were examined in the hypopharyngeal gland of workers at different developmental stages (nurse, forager and reversed nurse stages). The results indicated that the relative expression levels of SV2C, eIF-4E, IMP, cell growth-regulating nucleolar protein and TGF-βR1 were reversed at reversed nurse stage compared to forager stage. We concluded that these genes are possibly candidates related to hypopharyngeal gland development or royal jelly secretion

Speaker Recognition based on a Novel Hybrid Algorithm

AbstractUsing Probabilistic Neural Network (PNN) to recognize speaker is one of the research of branch of speaker recognition. PNN's ability of recognition is so dependent on the value of its smoothing factor that its ability of recognition is not that good. To solve this problem, we proposed a novel hybrid algorithm (DFOA-SOM-PNN) to improve PNN's ability of recognition. Firstly, it uses SOM to cluster MFCC speech characteristics parameters which can reduce storage of data and calculation, and good reflect feature of MFCC. Secondly, it uses an improved algorithm of Fruit fly Optimization Algorithm (FOA): Double group FOA (DFOA), which optimizes the smooth factor of PNN. The experimental results show that DFOA have better global convergence and fast convergence speed than FOA, and the proposed hybrid algorithm has better performance in speaker recognition

A new species of Polycelis (Platyhelminthes, Tricladida, Planariidae) from China

In this paper, a new species of Polycelis of the family Planariidae from China is described. Mature individuals have 80–140 eyespots; the testes are well-developed and most of them occupy the entire dorso-ventral space; the penis is a long cone with well-developed musculature; the boundary between the penis bulb and penis papilla is vague and the bulbar cavity is not observed; the bursal canal is surrounded by a well-developed coat of circular muscles, and a thin layer of longitudinal muscles. The karyotype shows a diploid complement of 38 chromosomes, with the formula 2n = 38 = 24m + 14sm