A Simulation Method to Estimate Two Types of Time-Varying Failure Rate of Dynamic Systems

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Zhonglai Wang ◽  
Xiaoqiang Zhang ◽  
Hong-Zhong Huang ◽  
Zissimos P. Mourelatos
Keyword(s):  
Failure Rate ◽  
Dynamic Systems ◽  
Saddlepoint Approximation ◽  
Simulation Method ◽  
Copula Function ◽  
Type I ◽  
Time Varying ◽  
Type Ii ◽  
Time Intervals ◽  
Function Type

The failure rate of dynamic systems with random parameters is time-varying even for linear systems excited by a stationary random input. In this paper, we propose a simulation-based method to estimate two types (type I and type II) of time-varying failure rate of dynamic systems. The input stochastic processes are discretized in time and the trajectories of the output stochastic process are calculated. The time of interest is partitioned into a series of time intervals and the saddlepoint approximation (SPA) is employed to estimate the probability of failure in each interval. Type I follows the commonly used definition of failure rate. It is estimated at discrete time intervals using SPA and the correlation information from a properly selected time-dependent copula function. Type II is a proposed new concept of time-varying failure rate. It provides a way to predict the failure rate considering a virtual “good-as-old” repair action of repairable dynamic systems. The effectiveness of the proposed method is illustrated with a vehicle vibration example.

A Simulation Method to Estimate the Time-Varying Failure Rate of Dynamic Systems

2014 ◽  
Author(s):  
Zhonglai Wang ◽  
Xiaoqiang Zhang ◽  
Hong-Zhong Huang ◽  
Zissimos P. Mourelatos
Keyword(s):  
Failure Rate ◽  
Dynamic Systems ◽  
Saddlepoint Approximation ◽  
Planning Horizon ◽  
Simulation Method ◽  
Probability Of Failure ◽  
Small Time ◽  
Time Interval ◽  
Time Varying ◽  
Time Step

The failure rate of dynamic systems with random parameters is time-varying even for linear systems excited by a stationary random input. In this paper, we propose a simulation-based method to estimate this time-varying failure rate. The input and output stochastic processes are discretized using a small time step to calculate the trajectories of the output stochastic process accurately through simulation. The planning horizon (time of interest) is then partitioned into a series of longer correlated time intervals and the Saddlepoint approximation (SPA) is employed to estimate the distribution of maximum response and thus obtain the probability of failure in each time interval. Using the same simulated trajectories with SPA, a time-dependent copula is built to provide the correlation between the response in each time interval and the response up to that time interval. The time-varying failure rate is finally estimated at each discrete time, using the probability of failure in each time interval and the correlation information from the estimated copula. The effectiveness of the proposed method is illustrated with a vehicle vibration example.

scholarly journals The non-essentiality of essential genes suggests a loss-of-function therapeutic strategy for loss-of-function human diseases

2016 ◽  
Author(s):  
Piaopiao Chen ◽  
Dandan Wang ◽  
Han Chen ◽  
Zhenzhen Zhou ◽  
Xionglei He
Keyword(s):  
Side Effects ◽  
Large Scale ◽  
Therapeutic Strategy ◽  
Essential Gene ◽  
Large Population ◽  
Essential Genes ◽  
Type I ◽  
Type Ii ◽  
Loss Of Function ◽  
Function Type

Essential genes refer to those whose null mutation leads to lethality or sterility. We propose that the fatal effect of inactivating an essential gene can be attributed to either the loss of indispensable core cellular function (type I), or the gain of fatal side effects after losing dispensable periphery function (type II). In principle, inactivation of the type I essential genes can be rescued only by re-gain of the core functions, whereas inactivation of the type II essential genes could be rescued by a further loss of function of another gene to eliminate the otherwise fatal side effects. Because such loss-of-function rescuing mutations may occur spontaneously, type II essential genes may become non-essential in a few individuals of a large population. We tested this idea in the yeastSacchromyces cerevisiae. Large-scale whole genome sequencing of such essentiality-reversing mutants reveals 14 cases where inactivation of an essential gene is rescued by loss-of-function mutations on another gene. In particular, the essential gene encoding the enzyme adenylosuccinate lyase (ADSL) is shown to be type II, suggesting a loss-of-function therapeutic strategy for the human disorder ADSL deficiency. A proof-of-principle test of this strategy in the nematodeCaenorhabditis elegansshows promising results.

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

Comparative surface and ultrastructural views of methylotrophic bacteria by TEM, STEM, SE, and freeze-etch electron microscopy.

1987 ◽  
Vol 45 ◽  
pp. 792-793
Author(s):  
T.A. Fassel ◽  
M.J. Schaller ◽  
M.E. Lidstrom ◽  
C.C. Remsen
Keyword(s):  
Cytoplasmic Membrane ◽  
Structural Features ◽  
Methylotrophic Bacteria ◽  
Type I ◽  
Type Ii ◽  
Membrane Complex ◽  
Oxidation Of Methane ◽  
Methane Oxidizing Bacteria ◽  
Wall Structures ◽  
Methylomonas Albus

Methylotrophic bacteria play an Important role in the environment in the oxidation of methane and methanol. Extensive intracytoplasmic membranes (ICM) have been associated with the oxidation processes in methylotrophs and chemolithotrophic bacteria. Classification on the basis of ICM arrangement distinguishes 2 types of methylotrophs. Bundles or vesicular stacks of ICM located away from the cytoplasmic membrane and extending into the cytoplasm are present in Type I methylotrophs. In Type II methylotrophs, the ICM form pairs of peripheral membranes located parallel to the cytoplasmic membrane. Complex cell wall structures of tightly packed cup-shaped subunits have been described in strains of marine and freshwater phototrophic sulfur bacteria and several strains of methane oxidizing bacteria. We examined the ultrastructure of the methylotrophs with particular view of the ICM and surface structural features, between representatives of the Type I Methylomonas albus (BG8), and Type II Methylosinus trichosporium (OB-36).

OPTICAL STUDIES OF TYPE I AND TYPE II RECOMBINATION IN GaAs-AlAs QUANTUM WELLS

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-525-C5-528 ◽  
Author(s):  
K. J. MOORE ◽  
P. DAWSON ◽  
C. T. FOXON
Keyword(s):  
Quantum Wells ◽  
Type I ◽  
Type Ii ◽  
Optical Studies

An old friend is better than two new ones? Approaches to market research in the context of digital transformation for the antitrust laws enforcement

2020 ◽  
pp. 37-55 ◽  
Author(s):  
A. E. Shastitko ◽  
O. A. Markova
Keyword(s):  
Business Models ◽  
Rapid Development ◽  
Digital Transformation ◽  
Market Definition ◽  
Type I ◽  
Type Ii ◽  
Digital Platforms ◽  
Advantages And Disadvantages ◽  
Pass Through ◽  
Type Ii Errors

Digital transformation has led to changes in business models of traditional players in the existing markets. What is more, new entrants and new markets appeared, in particular platforms and multisided markets. The emergence and rapid development of platforms are caused primarily by the existence of so called indirect network externalities. Regarding to this, a question arises of whether the existing instruments of competition law enforcement and market analysis are still relevant when analyzing markets with digital platforms? This paper aims at discussing advantages and disadvantages of using various tools to define markets with platforms. In particular, we define the features of the SSNIP test when being applyed to markets with platforms. Furthermore, we analyze adjustment in tests for platform market definition in terms of possible type I and type II errors. All in all, it turns out that to reduce the likelihood of type I and type II errors while applying market definition technique to markets with platforms one should consider the type of platform analyzed: transaction platforms without pass-through and non-transaction matching platforms should be tackled as players in a multisided market, whereas non-transaction platforms should be analyzed as players in several interrelated markets. However, if the platform is allowed to adjust prices, there emerges additional challenge that the regulator and companies may manipulate the results of SSNIP test by applying different models of competition.

Two Different UGT1A1 Mutations causing Crigler–Najjar Syndrome types I and II in an Iranian Family

2015 ◽  
Vol 24 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Yoshihiro Maruo ◽  
Mahdiyeh Behnam ◽  
Shinichi Ikushiro ◽  
Sayuri Nakahara ◽  
Narges Nouri ◽  
...  
Keyword(s):  
Serum Bilirubin ◽  
Total Serum Bilirubin ◽  
Total Serum ◽  
Compound Heterozygous ◽  
Type I ◽  
Syndrome Type ◽  
Type Ii ◽  
Wild Type ◽  
Iranian Family ◽  
Udp Glucuronosyltransferase

Background: Crigler–Najjar syndrome type I (CN-1) and type II (CN-2) are rare hereditary unconjugated hyperbilirubinemia disorders. However, there have been no reports regarding the co-existence of CN-1 and CN-2 in one family. We experienced a case of an Iranian family that included members with either CN-1 or CN-2. Genetic analysis revealed a mutation in the bilirubin UDP-glucuronosyltransferase (UGT1A1) gene that resulted in residual enzymatic activity.Case report: The female proband developed severe hyperbilirubinemia [total serum bilirubin concentration (TB) = 34.8 mg/dL] with bilirubin encephalopathy (kernicterus) and died after liver transplantation. Her family history included a cousin with kernicterus (TB = 30.0 mg/dL) diagnosed as CN-1. Her great grandfather (TB unknown) and uncle (TB = 23.0 mg/dL) developed jaundice, but without any treatment, they remained healthy as CN-2. Results: The affected cousin was homozygous for a novel frameshift mutation (c.381insGG, p.C127WfsX23). The affected uncle was compound heterozygous for p.C127WfsX23 and p.V225G linked with A(TA)7TAA. p.V225G-UGT1A1 reduced glucuronidation activity to 60% of wild-type. Thus, linkage of A(TA)7TAA and p.V225G might reduce UGT1A1 activity to 18%–36 % of the wild-type. Conclusion: Genetic and in vitro expression analyses are useful for accurate genetic counseling for a family with a history of both CN-1 and CN-2. Abbreviations: CN-1: Crigler–Najjar syndrome type I; CN-2: Crigler–Najjar syndrome type II; GS: Gilbert syndrome; UGT1A1: bilirubin UDP-glucuronosyltransferase; WT: Wild type; TB: total serum bilirubin.

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