Exploration and exploitation in the presence of network externalities

This paper examines the conditions under which exploration of a new, incompatible technologyis conducive to firm growth in the presence of network externalities. In particular, this studyis motivated bythe divergent evolutions of the PC and the workstation markets in response to a new technology: reduced instruction set computing (RISC). In the PC market, Intel has developed new microprocessors bymaintaining compatibilitywith the established architecture, whereas it was radicallyr eplaced byRISC in the workstation market. History indicates that unlike the PC market, the workstation market consisted of a large number of power users, who are less sensitive to compatibilitythan ordinaryusers. Our numerical analysis indicates that the exploration of a new, incompatible technologyis more likelyto increase the chance of firm growth when there are a substantial number of power users or when a new technologyis introduced before an established technologytakes off. (; ; ;

Parameterisation of a biodiesel plant process flow sheet model

© 2016 Elsevier Ltd This paper presents results of parameterisation of typical input–output relations within process flow sheet of a biodiesel plant and assesses parameterisation accuracy. A variety of scenarios were considered: 1, 2, 6 and 11 input variables (such as feed flow rate or a heater's operating temperature) were changed simultaneously, 3 domain sizes of the input variables were considered and 2 different surrogates (polynomial and high dimensional model representation (HDMR) fitting) were used. All considered outputs were heat duties of equipment within the plant. All surrogate models achieved at least a reasonable fit regardless of the domain size and number of dimensions. Global sensitivity analysis with respect to 11 inputs indicated that only 4 or fewer inputs had significant influence on any one output. Interaction terms showed only minor effects in all of the cases.This project is funded by the National Research Foundation (NRF), Prime Minister's Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme

Identifying the favored mutation in a positive selective sweep.

Most approaches that capture signatures of selective sweeps in population genomics data do not identify the specific mutation favored by selection. We present iSAFE (for "integrated selection of allele favored by evolution"), a method that enables researchers to accurately pinpoint the favored mutation in a large region (∼5 Mbp) by using a statistic derived solely from population genetics signals. iSAFE does not require knowledge of demography, the phenotype under selection, or functional annotations of mutations

Insulator materials for interface passivation of Cu(In,Ga)Se2 thin films

In this work, Metal-Insulator-Semiconductor (MIS) structures were fabricated in order to study different types of insulators, namely, aluminum oxide (Al2O3), silicon nitride (Si3Nx) and silicon oxide (SiOx) to be used as passivation layers in Cu(In,Ga)Se2 (CIGS) thin film solar cells. The investigated stacks consisted of SLG/Mo/CIGS/insulator/Al. Raman scattering and Photoluminescence measurements were done to verify the insulator deposition influence on the CIGS surface. In order to study the electrical properties of the CIGS-insulator interface, capacitance vs. conductance and voltage (C-G-V) measurements were done to estimate the number and polarity of fixed insulator charges (Qf). The density of interface defects (Dit) was estimated from capacitance vs. conductance and frequency (C-G-f) measurements. This study evidences that the deposition of the insulators at high temperatures (300 ºC) and the use of sputtering technique cause surface modification on the CIGS surface. We found that, by varying the SiOx deposition parameters, it is possible to have opposite charges inside the insulator, which would allow its use in different device architectures. The material with lower Dit values was Al2O3 when deposited by sputtering.publishe

Growth of Sb2Se3 thin films by selenization of RF sputtered binary precursors

In this work we present a method to grow Sb2Se3 thin films with a potential use as absorber layers in solar cell structures. The films were grown on several substrates: soda-lime glass, Mo coated soda-lime glass and Si . The Sb-Se precursor’s films were deposited by RF magnetron sputtering and then selenized under a H2Se gas flow. Different selenization temperatures were tested and analysed. Compositional and morphological analyses were performed by Energy Dispersive Spectroscopy and Scanning Electron Microscopy, respectively. Phase identification and structural characterization were done by X-ray Diffraction and Raman scattering spectroscopy showing that Sb2Se3 is the dominant phase with an orthorhombic crystalline structure. Traces of rhombohedral and amorphous Se secondary phases were also observed supported by their Se-rich compositions. Visible-NIR reflectance measurements allowed to extract a direct bandgap with a value close to 1.06 eV. Photoluminescence spectroscopy shows an emission with a broad band at 0.85 eV for samples selenized at lower temperatures and an intense peak at 0.75 eV for the sample selenized at higher temperatures. Electrical characterization shows low free hole concentrations and mobilities. At low temperatures, the nearest neighbour hopping is the dominant mechanism for the electronic transport for the analysed samples. Both electrical and optical properties are influenced by the type of defects present on samples. A discussion is made on the properties that need to be improved in order that these films can be integrated into thin film solar cells.publishe

Technical Letter Report: Evaluation and Analysis of a Few International Periodic Safety Review Summary Reports

At the request of the United States (U.S.) government, the International Atomic Energy Agency (IAEA) assembled a team of 20 senior safety experts to review the regulatory framework for the safety of operating nuclear power plants in the United States. This review focused on the effectiveness of the regulatory functions implemented by the NRC and on its commitment to nuclear safety and continuous improvement. One suggestion resulting from that review was that the U.S. Nuclear Regulatory Commission (NRC) incorporate lessons learned from periodic safety reviews (PSRs) performed in other countries as an input to the NRC’s assessment processes. In the U.S., commercial nuclear power plants (NPPs) are granted an initial 40-year operating license, which may be renewed for additional 20-year periods, subject to complying with regulatory requirements. The NRC has established a framework through its inspection, and operational experience processes to ensure the safe operation of licensed nuclear facilities on an ongoing basis. In contrast, most other countries do not impose a specific time limit on the operating licenses for NPPs, they instead require that the utility operating the plant perform PSRs, typically at approximately 10-year intervals, to assure continued safe operation until the next assessment. The staff contracted with Argonne National Laboratory (Argonne) to perform a pilot review of selected translated PSR assessment reports and related documentation from foreign nuclear regulatory authorities to identify any potential new regulatory insights regarding license renewal-related topics and NPP operating experience (OpE). A total of 14 PSR assessment documents from 9 countries were reviewed. For all of the countries except France, individual reports were provided for each of the plants reviewed. In the case of France, three reports were provided that reviewed the performance assessment of thirty-four 900-MWe reactors of similar design commissioned between 1978 and 1988. All of the reports reviewed were the regulator’s assessment of the PSR findings rather than the original PSR report, and all but one were English translations from the original language. In these reviews, it was found that most of the countries base their regulatory guidance to some extent (and often to a large extent) on U.S. design codes and standards, NRC regulatory guidance, and U.S. industry guidance. In addition, many of the observed operational technical issues and OpE events reported for U.S. reactors are also cited in the PSR reports. The PSR reports also identified a number of potential technical material/component performance issues and OpE events that are not commonly reported for U.S. plants

Sorghum grain mold: variability in fungal complex

The grain mold complex in sorghum {Sorghum bicolor) involves a number of pathogenic and saprophytic fungi that vary in their frequencies and severities under different environmental conditions (Bandyopadhyay et al. 2000). To provide genetic management for grain mold In sorghum, a clear understanding of the major pathogenic fungi and their variability under different environments is critical. Among the major pathogenic fungi, Fusarium monitiforme (F. verticiOoides) is known to produce fumonisins, a mycotoxin of concern for the use of molded sorghum grains as food and feed (Marasas 1996, Bhat et al. 1997). With the above objective we Initiated a collaborative Sorghum Grain Mold Variability Nursery (SGMVN) between ICRISAT and the All India Coordinated Sorghum Improvement Project (AICSIP) ot the Indian Council of Agricultural Research (ICAR). The nursery was coordinated by ICRISAT and conducted at four locations In India during the rainy season 2002. The results of the trials are presented

From Business Model to Business Modelling: Modularity and Manipulation

The concept of modularity has gained considerable traction in technology studies as a way to conceive, describe and innovate complex systems, such as product design or organizational structures. In the recent literature, technological modularity has often been intertwined with business model innovation, and scholarship has started investigating how modularity in technology affects changes in business models, both at the cognitive and activity system levels. Yet we still lack a theoretical definition of what modularity is in the business model domain. Business model innovation also encompasses different possibilities of modeling businesses, which are not clearly understood nor classified. We ask when, how and if modularity theory can be extended to business models in order to enable effective and efficient modeling. We distinguish theoretically between modularity for technology and for business models, and investigate the key processes of modularization and manipulation. We introduce the basic operations of business modeling via modular operators adapted from the technological modularity domain, using iconic examples to develop an analogical reasoning between modularity in technology and in business models. Finally, we discuss opportunities for using modularity theory to foster the understanding of business models and modeling, and develop a challenging research agenda for future investigations

Sustaining entrepreneurial business: a complexity perspective on processes that produce emergent practice

This article examines the management practices in an entrepreneurial small firm which sustain the business. Using a longitudinal qualitative case study, four general processes are identified (experimentation, reflexivity, organising and sensing), that together provide a mechanism to sustain the enterprise. The analysis draws on concepts from entrepreneurship and complexity science. We suggest that an entrepreneur’s awareness of the role of these parallel processes will facilitate their approaches to sustaining and developing enterprises. We also suggest that these processes operate in parallel at multiple levels, including the self, the business and inter-firm networks. This finding contributes to a general theory of entrepreneurship. A number of areas for further research are discussed arising from this result

Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship