Is the List of Incomplete Open Cubes Complete?

Variations of Incomplete Open Cubes is the major project by the twentieth-century conceptual artist Sol LeWitt. In this paper we interpret the enumerative component of the project as embeddings of graphs. This formulation permits use of an algorithm to check the completeness of the list of the structures produced by the artist. Our conclusion is that the artist found the correct number of structures (that is, 122), but that his list contains a mistake in the presentation of a pair of incomplete cubes, a discovery that appears not to have been noted before.     

Spin Effects on Heat Current Through a Quantum Dot Attached to Ferromagnetic Leads

A heat current originating from electron–phonon coupling in a quantum dot (QD) molecule connected to ferromagnetic leads is studied by the non-equilibrium Green’s function technique. The system is driven out of equilibrium by a temperature gradient (thermal bias) applied across the two terminals of the structure. We find that when the magnetic moments of the two leads are arranged in parallel configuration, the heat current is not sensitive to the leads’ ferromagnetism, whereas in the case of antiparallel configuration, the magnitude of the heat current increases with increasing spin polarization of the leads, with the reduction of the electric current’s intensity. We also find that the ferromagnetism on the leads can amplify the heat rectification effect occurring for some particular dot levels, i.e., the strength of the heat flowing between the QD and the phonon bath can be very small for one direction of the temperature gradient, while it becomes quite large when the corresponding direction of the temperature gradient is reversed.     

Software assurance practices for mobile applications

Mobile software applications have to cope with a particular environment that involves small size, limited resources, high autonomy requirements, competitive business models and many other challenges. To provide development guidelines that respond to these needs, several practices have been introduced; however, it is not clear how these guidelines may contribute to solve the issues present in the mobile domain. Furthermore, the rapid evolution of the mobile ecosystem challenges many of the premises upon which the proposed practices were designed. In this paper, we present a survey of the literature on software assurance practices for mobile applications, with the objective of describing them and assessing their contribution and success. We identified, organized and reviewed a body of research that spans in three levels: software development processes, software product assurance practices, and software implementation practices. By carrying out this literature survey, we reviewed the different approaches that researchers on Software Engineering have provided to address the needs that raise in the mobile software development arena. Moreover, we review the evolution of these practices, identifying how the constant changes and modernization of the mobile execution environment has impacted the methods proposed in the literature. Finally, we introduced discussion on the application of these practices in a real productive setting, opening an area for further research that may determine if practitioners have followed the proposed assurance paradigms.     

Flexible generification: ICT standardization strategies and service innovation in health care

Standards have played an important but often unrecognized role in the development of modern organizations. This role is accentuated by today’s growth of large business and government infrastructures, in the turbulent processes of globalization. In this paper, we investigate the relationships – and tensions – between standardization strategies and service innovation in the health-care sector. Our empirical material is seven longitudinal case studies in the Norwegian health-care sector, collected and analysed over a period of 20 years. We identify three generic standardization strategies; anticipatory standardization, integrated solutions and flexible generification. We argue that the first two strategies do not support service innovation while the strategy of flexible generification does so. We consider our results important for the evolution of the future ICT-enabled service economy.     

Smart homes and their users: a systematic analysis and key challenges

Published research on smart homes and their users is growing exponentially, yet a clear understanding of who these users are and how they might use smart home technologies is missing from a field being overwhelmingly pushed by technology developers. Through a systematic analysis of peer-reviewed literature on smart homes and their users, this paper takes stock of the dominant research themes and the linkages and disconnects between them. Key findings within each of nine themes are analysed, grouped into three: (1) views of the smart home—functional, instrumental, socio-technical; (2) users and the use of the smart home—prospective users, interactions and decisions, using technologies in the home; and (3) challenges for realising the smart home—hardware and software, design, domestication. These themes are integrated into an organising framework for future research that identifies the presence or absence of cross-cutting relationships between different understandings of smart homes and their users. The usefulness of the organising framework is illustrated in relation to two major concerns—privacy and control—that have been narrowly interpreted to date, precluding deeper insights and potential solutions. Future research on smart homes and their users can benefit by exploring and developing cross-cutting relationships between the research themes identified.     

Optimal Cyclic Exploitation of Renewable Resources

The paper contributes to the topic of optimal utilization of spatially distributed renewable resources. Namely, a problem of “sustainable” optimal cyclic exploitation of a renewable resource with logistic law of recovery is investigated. The resource is distributed on a circle and is collected by a single harvester moving along the circle. The recovering and harvesting rates are position dependent, and the latter depends also on the velocity of the harvester, which is considered as a control. The existence of an optimal solution is proved, as well as necessary optimality conditions for the velocity of the harvester. On this base, a numerical approach is proposed, and some qualitative properties of the optimal solutions are established. The results are illustrated by numerical examples, which reveal some economically meaningful features of the optimal harvesting.     

Facile fabrication of In:Ge/Cu nano-octahedra film for improving photoelectrochemical properties

The novel In:Ge/Cu nano-octahedra photoelectric film, a kind of metal-semiconductor-metal (MSM) like structures, was prepared from by a facile two-step electrodeposition process, which In:Ge and Cu nano-octahedra were successively deposited on the indium tin oxide (ITO) substrates from aqueous solution. With the modification of Cu nano-octahedral, the photoresponse and photoactive current of the In:Ge films has significantly improved 88 flods under illuminations (wavelength range: 365, 532 and 805 nm). Notably, the In:Ge/Cu nano-octahedra films exhibit excellent photoelectrochemical properties in wide wavelength range from the UV to near-infrared. This novel photoelectric film shows great potential applications in optoelectronic devices and photodetectors, and the facilely synthesis route can provide an enlightening insight for the fabrication of photoelectric devices and high-performance energy conversion systems.     

Energy Detection in Hoyt/Gamma Fading Channel with Micro-Diversity Reception

Spectrum sensing is the important function of cognitive radio and energy detection is the most popular technique used for spectrum sensing. Detection of the availability of unused spectrum for the secondary user becomes difficult when the channel is affected by composite multipath/shadowed fading. In this paper, the performance analysis of an Energy Detector in Hoyt/gamma composite fading channel with Maximum Ratio Combining employing micro-diversity is analyzed. Analytical expressions for performance parameters, i.e., the average probability of detection and the average area under the receiver operating characteristics curve are evaluate. The effect of diversity on the performance of energy detector is also studied. Monte-Carlo simulation results have verified the accuracy of the proposed analysis.