Multiple inverse problem

The problem of providing the required level of quality of products and/or technological processes often becomes difficult due to the fact that there is no general theory for determining optimal sets of values of primary factors, i.e. output parameters of parts and units comprising an object as well as ensuring the equivalence of object parameters to the quality requirements. This is the main reason why the development of complex systems and objects of vital importance takes several years. To create this theory, one has to overcome a number of difficulties and solve the following tasks: creation of reliable and stable mathematical models that indicate the influence of primary factors on output parameters; determination of accurate solutions when mathematical models are poorly stipulated; and creation of a method of assigning nominal values and tolerances for primary factors with regard to economical, technological and other criteria. All of the above-listed tasks are equally important. The present work is an attempt to describe a solution for this problem. The mathematically formalized aspect of the problem of providing the required level of quality has been called the “multiple inverse problem”

Estimation of origin-destination matrix from traffic counts: the state of the art

The estimation of up-to-date origin-destination matrix (ODM) from an obsolete trip data, using current available information is essential in transportation planning, traffic management and operations. Researchers from last 2 decades have explored various methods of estimating ODM using traffic count data. There are two categories of ODM; static and dynamic ODM. This paper presents studies on both the issues of static and dynamic ODM estimation, the reliability measures of the estimated matrix and also the issue of determining the set of traffic link count stations required to acquire maximum information to estimate a reliable matrix

Identification of Physical and Mechanical Properties of Compound by Solving Inverse Problems

The paper presents a method of identification of physical and mechanical characteristics of the compound (calculated and experimental test method parameters). The idea of the method is that the studied material is connected with other materials, the characteristics of which are well known and differ from the characteristics of the material. Desired physical and mechanical properties should be considered unknown in the proposed calculation model, and the values of the parameters of trial constructions that can be measured accurately with experimental methods in the process of product operation, as well as characteristics of test materials and geometric dimensions of proposed structures are suggested to be placed in the same model as input information

Calculation of mechanical stresses in adjoint system of electronic component and compound and strength assessment

The paper represents mathematical model and formulas developed for project calculations which are applied to sealed electronic units and provide assessing strength of passive electronic components having revolution shape (capacitors, resistors, diodes, pins, etc.). The stress calculation has been produced for materials of resistor and compound in the temperature interval (from –60 to +70°C) along the radius of resistor and compound

Drosophila E2F and DP genes : their role in the regulation of G1-S progression and the activity of DNA replication origins

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 1998.Includes bibliographical references.Late in Drosophila embryogenesis the cells giving rise to most of the larval tissues switch from a mitotic cycle to the endo cycle. The endo cycle consists of only S phase and a gap phase, leading to polyteny. It is preceded by the first detectable G1 period in Drosophila embryogenesis and developmentally regulated induction of S phase genes in the pattern of DNA synthesis. My analysis of the regulation of G1-S progression began with a genetic screen for mutations that disrupt the transcription pattern of S phase genes in mitotic and polytene cells of the embryo. A number of mutations in known and novel genes were isolated. Further analysis and phenotypic characterization has focused on the mutations that nearly eliminate the transcription of S phase genes in mitotic and polytene cells. These mutations are in the Drosophila homologs to the mammalian E2F and DP genes. The E2F transcription factor, a heterodimer of E2F and DP subunits, is linked to the G1-S transition in mammalian cells. Five mutations in the Drosophila DP gene (dDP) were isolated and provide the first opportunity to examine the in vivo role of this gene. Despite a pronounced effect on the G1-S transcription of S phase genes in dDP and dE2F mutant embryos, a block to replication was not observed. Null mutations in dDP and dE2F cause lethality late in development with some mitotic and polytene tissues being underdeveloped or absent. The mutant phenotypes reveal a positive role for E2F/DP in cell cycle progression in mitotic and endo cycle cells. Weak alleles of dE2F and dDP develop to adulthood and exhibit defects in oogenesis. Analyses of these mutants showed that E2F/DP controls differential regulation of replication origins within polyploid S phase. In ovarian nurse cells, E2F/DP limits replication of heterochromatic sequences. In follicle cells, E2F/DP is required to shut off genomic replication and activate the amplification of chorion loci. In addition to the positive and negative effects on the activity of replication origins, E2F/DP is necessary for nuclear lamin breakdown in nurse cells and subsequent nurse cell apoptosis.by Irena Royzman.Ph.D

Acoustic emission and methods of its registration (review)

Lately a tendency is observed for the steady growth of requirements applied both to construction materials as well as to the methods of estimation of their reliability and quality. Particular attention is paid to the development of new, physically reasonable criteria of structural durability of materials, based on comprehensive study of the phenomena, which form the basis of processes of deformation and fracture. Such approach is supposed to enhance our understanding of the nature of durability and mechanisms of fracture of materials on different scale levels. This is possible only when analysis of these phenomena is accomplished by means of modern physical research methods as well as applying acoustic emission techniques for diagnostics of the fractures

Methods for testing and optimizing composite ceramics-compound joints by solving inverse problems of mechanics

The paper demonstrates methods for testing and selecting composite ceramics-compounds by solving inverse problems of mechanics. A method for the identification of physical and mechanical characteristics of the compound is proposed. The idea of the method is that the studied material is connected with other materials, the characteristics of which are well known and differ from the characteristics of the material. Desired physical and mechanical properties should be considered unknown in the proposed calculation model. Values of the parameters can be measured accurately with experimental methods in the process of product operation. Characteristics of test materials and geometric dimensions of proposed structures are suggested. The solution of the problem of optimizing the tolerances of physical and mechanical characteristics of materials is proposed. In order to ensure the strength of the structure, the geometric dimensions of the composite construction ceramic resistor-compound are suggested

Multiple inverse problem

The problem of providing the required level of quality of products and/or technological processes often becomes difficult due to the fact that there is no general theory for determining optimal sets of values of primary factors, i.e. output parameters of parts and units comprising an object as well as ensuring the equivalence of object parameters to the quality requirements. This is the main reason why the development of complex systems and objects of vital importance takes several years. To create this theory, one has to overcome a number of difficulties and solve the following tasks: creation of reliable and stable mathematical models that indicate the influence of primary factors on output parameters; determination of accurate solutions when mathematical models are poorly stipulated; and creation of a method of assigning nominal values and tolerances for primary factors with regard to economical, technological and other criteria. All of the above-listed tasks are equally important. The present work is an attempt to describe a solution for this problem. The mathematically formalized aspect of the problem of providing the required level of quality has been called the “multiple inverse problem”