The Information Technology Productivity Paradox Revisited: A Theoretical and Empirical Investigation in the Manufacturing Sector

The lack of empirical support for the positive economic impact of information technology (IT) has been called the IT productivity paradox. Even though output measurement problems have often been held responsible for the paradox, we conjecture that modeling limitations in production-economics-based studies and input measurement also might have contributed to the paucity of systematic evidence regarding the impact of IT. We take the position that output measurement is slightly less problematic in manufacturing than in the service sector and that there is sound a priori rationale to expect substantial productivity gains from IT investments in manufacturing and production management. We revisit the IT productivity paradox to highlight some potential limitations of earlier research and obtain empirical support for these conjectures. We apply a theoretical framework involving explicit modeling of a strategic business unit's (SBU)1 input choices to a secondary data set in the manufacturing sector. A widely cited study by Loveman (1994) with the same dataset showed that the marginal contribution of IT to productivity was negative. However, our analysis reveals a significant positive impact of IT investment on SBU output. We show that Loveman's negative results can be attributed to the deflator used for the IT capital. Further, modeling issues such as a firm's choice of inputs like IT, non-IT, and labor lead to major differences in the IT productivity estimates. The question as to whether firms actually achieved economic benefits from IT investments in the past decade has been raised in the literature, and our results provide evidence of sizable productivity gains by large successful corporations in the manufacturing sector during the same time period.     

Role of buffer layer at the p/i interface on the stabilized efficiency of a-Si solar cells

Light induced degradation of single junction and double junction a-Si:H solar cells has been studied. Cells with and without buffer layers at the p/i interfaces have been fabricated. It is found that light induced degradation is faster in the cells with buffer layers. Defect density increases faster and degraded efficiency with respect to the initial efficiency decreases at a higher rate for the cells with buffer layers. Spectral response study for double junction cells shows that collection efficiency decreases for the bottom cell only. So it is found that the absolute stabilized efficiency is highest for a double junction cell with buffer layer at the top cell only.     

Performance of double junction a-Si solar cells by using ZnO:Al films with different electrical and optical properties at the n/metal interface

High-quality ZnO:Al films have been prepared by using RF-magnetron-sputtering method with resistivity ranging from 10⁻¹ to 10⁻⁴ Ω cm and transmittance above 90% in visible region. We have fabricated small area (1 cm²) double junction (a-Si/a-Si) solar cells using ZnO/Al and ZnO/Ag as back contact. The conversion efficiency of double junction a-Si solar cell increases from 9.9% to 10.9% by using ZnO/Al back contact and to 11.4% by using ZnO/Ag as back contact. Effect of variation of thickness of i-layer on performance of the cell has also been studied.     

Effect of processing techniques on the performance of Epoxy/MWCNT nanocomposites

The aim of this study is to investigate the optimum technique to disperse Multi‐Walled Carbon Nanotubes (MWCNTs) in SC‐1 epoxy uniformly and to evaluate the effect of processing technique on the performance of SC‐1 epoxy. To achieve better dispersion, MWCNT was mixed with SC‐1 resin directly or premixed with a solvent and then mixed with SC‐1 resin after evaporating the solvent using sonication, thinky mixing and three‐roll mill methods either in isolation or combination. Flexural tests were performed to evaluate mechanical performances and results exhibit up to 27.13, 13.51, and 21.99% improvement on flexural strength, flexural modulus, and maximum strain, respectively, over neat epoxy with only 0.2 wt % loading. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) indicated improvement in storage modulus, T_g, inflection temperature, and residue content, respectively over neat SC‐1 epoxy. Thermal and mechanical properties at higher loading conditions were seen to either reduce or not significantly improve. This was attributed to high viscosity of nanocomposites as determined by rheological analysis which prevents good dispersion of MWNCTs into epoxy system at 0.4 wt % loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Implementation and performance evaluation of a distributed conjugate gradient method in a cloud computing environment

Cloud computing is an emerging technology where information technology resources are provisioned to users in a set of a unified computing resources on a pay per use basis. The resources are dynamically chosen to satisfy a user service level agreement and a required level of performance. A cloud is seen as a computing platform for heavy load applications. Conjugate gradient (CG) method is an iterative linear solver that is used by many scientific and engineering applications to solve a linear system of algebraic equations. CG generates a heavy load of computation, and therefore, it slows the performance of the applications using it. Distributing CG is considered as a way to increase its performance. However, running a distributed CG, based on a standard API, such as Message Passing Interface, in a cloud face many challenges, such as the cloud processing and networking capabilities. In this work, we present an in‐depth analysis of the CG algorithm and its complexity to develop adequate distributed algorithms. The implementation of these algorithms and their evaluation in our cloud environment reveal the gains and losses achieved by distributing the CG. The performance results show that despite the complexity of the CG processing and communication, a speedup gain of at least 1157.7 is obtained using 128 cores compared with National Aeronautics and Space Administration Advanced Supercomputing sequential execution. Given the emergence of clouds, the results in this paper analyzes performance issues when a generic public cloud, along with a standard development library, such as Message Passing Interface, is used for high‐performance applications, without the need of some specialized hardware and software. Copyright © 2012 John Wiley & Sons, Ltd.     

RCare: Extending Secure Health Care to Rural Area Using VANETs

In this paper, we propose a delay-tolerant secure long-term health care scheme, RCare, for collecting patient’s sensitive personal health information (PHI). Specifically, to minimize the overall health care cost, RCare provides network connectivity to rural areas using conventional transportation vehicles (e.g., cars, buses) as relay nodes. These vehicles are expected to store, carry, and forward the PHI to the health-service-provider located mostly at the city area following an opportunistic routing. RCare improves network performance by providing incentive to the cooperative vehicles, and encompasses identity based cryptography to ensure security and privacy of the PHI during the routing period by using short digital signature and pseudo-identity. Network fairness and resistance to different possible attacks are also ensured by RCare. Extensive security and performance analyses demonstrate that RCare is able to achieve desired security requirements with effectiveness in terms of high delivery ratio with acceptable communication delay.     

Changes in the localization of MHC class II positive cells in hen ovarian follicles during the processes of follicular growth, postovulatory regression and atresia

The aim of this study was to determine the changes in the population of major histocompatibility complex class II positive (MHC-II(+)) cells in ovarian follicles during the processes of follicular growth, postovulatory regression and follicular atresia in hens. Cryostat sections of ovarian stroma containing cortical follicles, small white follicles, the largest (F(1)) and third largest (F(3)) preovulatory follicles, postovulatory and atretic follicles of laying hens were prepared. The sections were immunostained for MHC-II molecules using mouse anti-chicken MHC-II monoclonal antibody and positive cells were counted using a computer-assisted image analyser under a light microscope. MHC-II(+) cells were localized in the theca layer of normally growing follicles including cortical follicles, small white follicles and F(3) and F(1) preovulatory follicles, whereas they were found in both the theca and granulosa layers in postovulatory and atretic follicles. The frequency of MHC-II(+) cells in the theca layer was significantly increased during follicular growth from cortical follicles to F(3) preovulatory follicles. Although the population of MHC-II(+) cells did not differ between F(3) and F(1) preovulatory follicles, it increased significantly in postovulatory follicles (P < 0.01). The population of MHC-II(+) cells was significantly greater in the theca layer of atretic follicles than in non-atretic follicles (P < 0.01). These results indicate that the antigen-presenting function via MHC-II increases in association with follicular growth. A marked increase in MHC-II(+) cells indicates that these cells may be involved in regression of postovulatory and atretic follicular tissues.     

The world photovoltaic scale: an international reference cell calibration program

This paper describes the World Photovoltaic Scale (WPVS) international reference cell calibration program. The WPVS provides a scale for PV performance measurements that has been established through round‐robin calibration of a group of primary monocrystalline Si reference cells and is traceable to Système International (SI) units. Procedures for recalibration of the reference cell group have been devised, along with procedures for admittance and calibration of new reference cells. A reference cell package has been designed that meets the unique needs of the WPVS. It is hoped that the existing WPVS group will eventually be replaced with cells of the new design that have passed a comprehensive acceptance‐test procedure. Copyright © 1999 John Wiley & Sons, Ltd.     

Quality of v-process moulds through the taguchi technique

The global consciousness for quality has motivated designers and manufacturing engineers to be engaged constantly in product and process development. The approach, quality by design, developed by Taguchi has produced a unique and powerful quality improvement discipline that differs from traditional practices. In the present paper, Taguchi's technique has been applied to obtain an optimal setting of V-process parameters. The results indicate that the sand grain fineness number and amplitude of vibration are the control factors. These factors affect both the mean and the variation of the bulk density of the V-process mould. The signal factor, that is the factor that affects only the mean value, is time of vibration. The insignificant factor is the degree of vacuum imposed. The optimum value of bulk density (1–588 gm/cm³) at the optimal setting of these parameters has been obtained and confirmed by further experiments.     

Modeling of the Oxygen Transfer Characteristics of a ‘See‐Saw’ Bioreactor

Animal cell line culture is difficult in the existing conventional bioreactors. A substantial amount of animal cells are destroyed by the impinging fan blades or entrapment inside the bubbles. An endeavor has been made to design and develop a new type of bioreactor suitable for animal cell culture. The bioreactor is named a ‘see‐saw’ bioreactor from its underlying principle of operation. In this paper, the oxygen transfer characteristics of the ‘see‐saw’ bioreactor are modeled and tried to be verified.