Classifying data quality problems in asset management

© Springer International Publishing Switzerland 2015. Making sound asset management decisions, such as whether to replace or maintain an ageing underground water pipe, are critical to ensure that organisations maximise the performance of their assets. These decisions are only as good as the data that supports them, and hence many asset management organisations are in desperate need to improve the quality of their data. This chapter reviews the key academic research on data quality (DQ) and Information Quality (IQ) (used interchangeably in this chapter) in asset management, combines this with the current DQ problems faced by asset management organisations in various business sectors, and presents a classification of the most important DQ problems that need to be tackled by asset management organisations. In this research, eleven semi structured interviews were carried out with asset management professionals in a range of business sectors in the UK. The problems described in the academic literature were cross checked against the problems found in industry. In order to support asset management professionals in solving these problems, we categorised them into seven different DQ dimensions, used in the academic literature, so that it is clear how these problems fit within the standard frameworks for assessing and improving data quality. Asset management professionals can therefore now use these frameworks to underpin their DQ improvement initiatives while focussing on the most critical DQ problems.

Technology management tools: Generalization, integration and configuration

Managers in technology-intensive businesses need to make decisions in complex and dynamic environments. Many tools, frameworks and processes have been developed to support managers in these situations, leading to a proliferation of such approaches, with little consistency in terminology or theoretical foundation, and a lack of understanding of how such tools can be linked together to tackle management challenges in an integrated way. As a step towards addressing these issues, this paper proposes the concept of an integrated 'toolkit', incorporating generalized forms of three core technology management tools that support strategic planning (roadmapping, portfolio analysis and linked analysis grids). © 2006 World Scientific Publishing Company.

Status of sturgeon aquaculture and sturgeon trade in China: a review based on two recent nationwide surveys

The authors reviewed the aquacultural history of Acipenseriformes in China, related the legal status and examined the current status of the cultured species or hybrids, origins of seedlings, quantities of production, geographic distribution in farming, and the sustainability for both restocking programmes and human consumption. The census shows that since 2000, the production of cultured sturgeons in China appears to have become the largest in the world. As of 2000, the rapid growth of sturgeon farming in China mainly for commercial purposes has shifted harvests in the Amur River from caviar production to the artificial culture of sturgeon seedlings. This dramatic development has also caused a series of extant and potential problems, including insufficient market availability and the impact of exotic sturgeons on indigenous sturgeon species. Annual preservation of sufficient higher-age sturgeons should be a national priority in order to establish a sustainable sturgeon-culture industry and to preserve a gene pool of critically endangered sturgeon species to prevent their extinction.

CYCLIC PEPTIDE HEPATOTOXINS FROM FRESH-WATER CYANOBACTERIAL (BLUE-GREEN-ALGAE) WATERBLOOMS COLLECTED IN CENTRAL CHINA

Toxic cyanobacteria (blue-green algae) waterblooms have been found in several Chinese water bodies since studies began there in 1984. Waterbloom samples for this study contained Anabaena circinalis, Microcystis aeruginosa and Oscillatoria sp. Only those waterblooms dominated by Microcystis aeruginosa were toxic by the intraperitoneal (i.p.) mouse bioassay. Signs of poisoning were the same as with known hepatotoxic cyclic peptide microcystins. One toxic fraction was isolated from each Microcystis aeruginosa sample. Two hepatotoxic peptides were purified from each of the fractions by high-performance liquid chromatography and identified by amino acid analysis followed by low and high resolution fast-atom bombardment mass spectrometry (FAB-MS). LD50 i.p. mouse values for the two toxins were 245-mu-g/kg (Toxin A) and 53-mu-g/g (Toxin B). Toxin content in the cells was 0.03 to 3.95 mg/g (Toxin A) and 0.18 to 3.33 mg/kg (Toxin B). The amino acid composition of Toxin A was alanine [1], arginine [2], glutamic acid [1] and beta-methylaspartic acid [1]; for Toxin B it was the same, except one of the arginines was replaced with a leucine. Low- and high-resolution FAB-MS showed that the molecular weights were 1,037 m/z (Toxin A) and 994 m/z (Toxin B), with formulas of C49H76O12N13 (Toxin A) and C49H75O12N10 (Toxin B). It was concluded that Toxin A is microcystin-RR and Toxin B is microcystin-LR, both known cyclic heptapeptide hepatotoxins isolated from cyanobacteria in other parts of the world. Sodium borohydride reduction of microcystin-RR yielded dihydro-microcystin-RR (m/z = 1,039), an important intermediate in the preparation of tritium-labeled toxin for metabolism and fate studies.

NUMERICAL ANALYSIS OF A NOVEL 980nm MICROCAVITY SEMICONDUCTOR OPTICAL AMPLIFIER WITH HIGH GAIN AND LOW NOISE

A novel microcavity semiconductor optical amplifier ( MCSOA) was proposed by incorporating top and bottom distributed Bragg reflectors ( DBRs) into the waveguide structure of conventional traveling-wave semiconductor optical amplifiers(TW-SOAs). The incoming( outgoing) light beam incidented onto (escaped from) the waveguide structure at a oblique angle through two optical windows, where the top DBR was etched away, and anti-reflection coating was deposited. The light beams inside the optical cavity were reflected repeatedly between two DBRs and propagated along waveguide in a zigzag optical path. The performance of the MCSOA was systematically investigated by extensive numerical simulation based on a traveling-wave model by taking into account the comprehensive effects of DBRs on both the amplification of signals and the filtering of spontaneous emission( SE). Our results show that the MCSOA is capable of achieving a fiber-to-fiber gain as high as 40dB and a low noise figure is less than 3.5dB.

Optical response of high-order band gap photonic crystal applying in-plane in one-dimensional integration

A new broadband filter, based on the high-order band gap in one-dimensional photonic crystal (PCs) of the form Si vertical bar air vertical bar Si vertical bar air vertical bar Si vertical bar air vertical bar Si vertical bar air vertical bar Si vertical bar air vertical bar Si, has been designed by the plane wave expansion method (PWEM) and transfer matrix method (TMM) and fabricated by lithography. The optical response of this filter to normal-incident and oblique-incident light proves that utilizing the high-order band gaps of PCs is an efficient method to lower the difficulties of fabricating PCs, increase the etching depth of semiconductor materials, and reduce the coupling loss at the interface between optical fibers and PC device. (c) 2007 Elsevier B.V. All rights reserved.

Properties of exchange interaction in Yb3Fe5O12 under extreme conditions

In Yb3Fe5O12, the exchange effective field can be expressed as H-eff = -lambda center dot center dot center dot M-Fe = -lambda chi(eff)center dot center dot center dot H-e = -gamma center dot center dot center dot H-e where gamma is named as the exchange field parameter and H-e is the external magnetic field. Then, in this paper, by the discussions on the characteristics of the exchange field parameter gamma, the properties of exchange interaction in ytterbium iron garnet (Yb3Fe5O12) are analyzed under extreme conditions (high magnetic fields and low temperatures). Our theory suggests that the exchange field parameter gamma is the function of the temperatures under different external magnetic fields, and gamma = a+b center dot center dot center dot T+c center dot center dot center dot T-2, where the coefficients a, b, c are associated with the external magnetic fields and the magnetized directions. Thus, the temperature-dependence, field-dependence and anisotropic characteristics of the exchange interaction in Yb3Fe5O12 are revealed. Also, excellent fits to the available experiments are obtained. (C) 2009 Elsevier B.V. All rights reserved.

Reduction of tensile stress in GaN grown on Si(111) by inserting a low-temperature AlN interlayer

This study describes the growth of a low-temperature AlN interlayer for crack-free GaN growth on Si(111). It is demonstrated that, in addition to the lower growth temperature, growth of the AlN interlayer under Al-rich conditions is a critical factor for crack-free GaN growth on Si(111) substrates. The effect of the AlN interlayer thickness and NH3/TMA1 ratios on the lattice constants of subsequently grown high temperature GaN was investigated by X-ray triple crystal diffraction. The results show that the elimination of micro-cracks is related to the reduction of the tensile stress in the GaN epitaxial layers. This was also coincident with a greater number of pits formed in the AlN interlayer grown under Al rich conditions. It is proposed that these pits act as centers for the generation of misfit dislocations, which in turn leads to the reduction of tensile stress. (C) 2004 Elsevier B.V. All rights reserved.

Strain accommodation of 3C-SiC grown on hydrogen-implanted Si (001) substrate

The hydrogen-implanted Si substrate has been used for the fabrication of the "compliant substrate", which can accommodate the mismatch strain during the heteroepitaxy. The compliance of the substrate can be modulated by the energy and dose of implanted hydrogen. In addition, the defects caused by implantation act as the gettering center for the internal gettering of the harmful metallic impurities. Compared with SiC films growth on substrate without implantation. all the measurements indicated that the mismatch strains in the SiC films grown on this substrate have been released and the crystalline qualities have been improved. It is a practical technique used for the compliant substrate fabrication and compatible with the semiconductor industry. (C) 2003 Elsevier B.V. All rights reserved.

Observation of quantum-confined Stark shifts in SiGe/Si type-I multiple quantum wells

Quantum-confined Stark shifts in SiGe/Si type-I multiple quantum wells are suggested by the bias dependence of the photocurrent spectra of p-i-n photodiodes. Both Stark redshift and blueshift have been observed for the same sample in the different ranges of electric fields applied to the quantum wells. The turnaround point corresponds to a certain electric field (named "critical" field). This phenomenon was generally predicted by Austin in 1985 [Phys. Rev. B 31, 5569 (1985)] and calculated in detail for SiGe quantum structure by Kim recently [Thin Solid Films 321, 215 (1998)]. The critical electric field obtained from the photocurrent spectra is in reasonable agreement with the theoretical prediction. (C) 2000 American Institute of Physics. [S0021-8979(00)03711-7].

Structural and optical characterization of InAs nanostructures grown on high-index InP substrates

The structural and optical properties of InAs layers grown on high-index InP surfaces by molecular beam epitaxy are investigated in order to understand the self-organization of quantum dots and quantum wires on novel index surfaces. Four different InP substrate orientations have been examined, namely, (1 1 1)B, (3 1 1)A, and (3 1 1)B and (1 0 0). A rich variety of InAs nanostructures is formed on the surfaces. Quantum wire-like morphology is observed on the (1 0 0) surface, and evident island formation is found on (1 1 1)A and (3 1 1)B by atomic force microscopy. The photoluminescence spectra of InP (1 1 1)A and (3 1 1)B samples show typical QD features with PL peaks in the wavelength range 1.3-1.55 mu m with comparable efficiency. These results suggest that the high-index substrates are promising candidates for production of high-quality self-organized QD materials for device applications. (C) 1999 Elsevier Science B.V. All rights reserved.