9 research outputs found
Consumption as a Social Process within Social Provisioning and Capitalism: Implications for Heterodox Economics
The article discusses consumption as a social process that is a part of social provisioning and is in an evolutionary interplay with other social processes. The discussion is grounded in, but is not limited to the contributions of Thorstein Veblen. The first section delineates social provisioning as a framework for consumption inquiry. This section emphasizes that social provisioning is a part of collective life process embedded in culture and nature, and that it is comprised by two general sets of activities – those motivated by money and those that are not motivated by making money. The second section delineates features of capitalism as a system, so that it provides a social context for consumption inquiry. The third section formulates a categorization of social processes, one of which is the consumption process. Further, the section delineates the meaning and components of the concepts: social activities, institutions, and habits of life and thought. The fourth section applies these concepts to consumption social process in the specific context of capitalism. The section discusses consumption activities; institutions and systems of provision; and habits of life and thought – illustrating with examples obtained from various disciplines. The section introduces “gated consumption” as an example of a habit of life and thought. It is argued that the formulated analysis transcends the cultural-material dualism. Finally, the article draws implications of the offered analysis, concluding that the category of “consumers” is of little use to heterodox economics
MIT's role in project Apollo. Volume 2: Optical, radar, and candidate subsystems
The development of optical, radar, and candidate subsystems for Project Apollo is discussed. The design and development of the optical subsystems for both the Apollo command and lunar spacecraft are described. Design approaches, problems, and solutions are presented. The evolution of radar interfaces with the GN&C system is discussed; these interfaces involved both hardware and software in a relatively complex interrelationship. The design and development of three candidate subsystems are also described. The systems were considered for use in Apollo, but were not incorporated into the final GN&C system. The three subsystems discussed are the star tracker-horizon photometer, the map and data viewer and the lunar module optical rendezvous system
Payload design requirements analysis (study 2.2). Volume 3. Guideline analysis
Payloads to be launched on the space shuttle/space tug/sortie lab combinations are discussed. The payloads are of four types: (1) expendable, (2) ground refurbishable, (3) on-orbit maintainable, and (4) sortie. Economic comparisons are limited to the four types of payloads described. Additional system guidelines were developed by analyzing two payloads parameterically and demonstrating the results on an example satellite. In addition to analyzing the selected guidelines, emphasis was placed on providing economic tradeoff data and identifying payload parameters influencing the low cost approaches
Space station systems: A bibliography with indexes (supplement 6)
This bibliography lists 1,133 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1987 and December 31, 1987. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems. The coverage includes documents that define major systems and subsystems, servicing and support requirements, procedures and operations, and missions for the current and future Space Station
Visoko-pouzdan prenos podataka kod bežičnih senzorskih mreža sa malom potrošnjom energije primenom 2D-SEC-DED tehnike kodiranja
This dissertation deals with the challenges of energy efficiency in
systems with limited resources of homogeneous and heterogeneous
wireless sensory networks for data collection applications in real
environmentals. This research covers several fields from physical
layer optimization up to network layer solutions. The problem which
has to be solved is viewed from three different perspectives: the
energy profile of the nodes with a special emphasis on the activity of
the sensing block, the network protocol with a special focus on
finding an adequate coding technique that need to reduce or eliminate
the request for retransmission and evaluating the range of
transmission for the proposed encoding technique.
If energy efficiency in wireless sensor networks is formulated as a
load balancing problem then the power management unit can
significantly contribute to reduction in power consumption. Power
management is implemented by switching on/off individual subblocks
of the sensor node independently of the hardware platform. By
reducing energy consumption both an extension of the lifetime of the
sensor node and sensor network, is achieved. The obtained energy
profiles reveal significant differences in energy consumption of
wireless sensor nodes depending in terms of external sensors number,
resolution of the analog-to-digital converter, network traffic
dynamics, topology of the network, applied coding techniques,
operating modes and activities during the lifetime of the sensor node
and other factors.
In this sense, the application of combination of power aware
techniques, such as the duty-cycling at system-level, and power
gating at the level of sensor elements, i.e. sensors, is proposed. An
evaluation of the approach shows that energy consumption reduction
three orders of magnitude on average can be achieved, when these
two techniques are incorporated into the sensor node.
On the other hand, in the wireless sensor networks, the choice of
coding scheme, i.e. channel coding depends on the application and
characteristics-, model-, type-errors appearing in the wireless channel.
For example, one encoding technique is preferred for use when burst
errors patterns are dominant, while another coding technique is more
acceptable in situations where noise causes random errors that are
either single or double in nature. Bearing this in mind, along with the
analysis of channel characteristics, in this dissertation, we propose a
new massage coding technique by which on extend traditional
protocols with aim to improve energy efficiency, while maintaining
high reliability in data transmission and low latency of message
transfer.
Namely, channel evaluation in wireless sensor networks used in
industry shows that most of the errors are of single or double nature,
and burst type errors are present, but rarely. In this context, in this
dissertation, an effective technique for correcting errors at a
destination (FEC) based on Hamming's coding scheme of relatively
low complexity, called Two Dimensional-Single Error Correction-
Double Error Detection (2D-SEC-DED) was developed. The
proposed encoding technique is intendet to minimize packet
retransmissions, thus saving energy. Evaluation of the proposed
encoding scheme shows that the code is able to correct all single
errors and 99.99% of double/multiple errors. The analysis was
carried out through the implementation, in MATLAB, of two versions
of Rendezvous Protocol for Long Life (RPLL), called Modified
RPLL (M-RPLL) and Ordinary RPLL (O-RPLL), respectively. The
energy gain achieved in this way is used to improve the performance
of wireless transmission, such as increasing of the transmission range.
As illustration, for indoor environment characterized by the path loss
exponent 4 at the target BER of 5 10 4 , the proposed encoding
scheme is able to improve the transmission distance by about 18 m ,
or the received signal strength (RSSI) by about 8.5 dBm compared to
wireless sensor networks with encoding schemes without possibility
to correct errors
Dynamical systems : control and stability
Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications"
summarize 164 and the Springer Proceedings summarize 60 best papers of university
teachers and students, researchers and engineers from whole the world. The papers were
chosen by the International Scientific Committee from 315 papers submitted to the
conference. The reader thus obtains an overview of the recent developments of dynamical
systems and can study the most progressive tendencies in this field of science
Using MapReduce Streaming for Distributed Life Simulation on the Cloud
Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp
A framework for real time collaborative editing in a mobile replicated architecture
Mobile collaborative work is a developing sub-area of Computer Supported Collaborative Work (CSCW). The future of this field will be marked by a significant increase in mobile device usage as a tool for co-workers to cooperate, collaborate and work on a shared workspace in real-time to produce artefacts such as diagrams, text and graphics regardless of their geographical locations. A real-time collaboration editor can utilise a centralised or a replicated architecture. In a centralised architecture, a central server holds the shared document as well as manages the various aspects of the collaboration, such as the document consistency, ordering of updates, resolving conflicts and the session membership. Every user's action needs to be propagated to the central server, and the server will apply it to the document to ensure it results in the intended document state. Alternatively, a decentralised or replicated architecture can be used where there is no central server to store the shared document. Every participating site contains a copy of the shared document (replica) to work on separately. Using this architecture, every user's action needs to be broadcast to all participating sites so each site can update their replicas accordingly. The replicated architecture is attractive for such applications, especially in wireless and ad-hoc networks, since it does not rely on a central server and a user can continue to work on his or her own local document replica even during disconnection period. However, in the absence of a dedicated server, the collaboration is managed by individual devices. This presents challenges to implement collaborative editors in a replicated architecture, especially in a mobile network which is characterised by limited resource reliability and availability. This thesis addresses challenges and requirements to implement group editors in wireless ad-hoc network environments where resources are scarce and the network is significantly less stable and less robust than wired fixed networks. The major contribution of this thesis is a proposed framework that comprises the proposed algorithms and techniques to allow each device to manage the important aspects of collaboration such as document consistency, conflict handling and resolution, session membership and document partitioning. Firstly, the proposed document consistency algorithm ensures the document replicas held by each device are kept consistent despite the concurrent updates by the collaboration participants while taking into account the limited resource of mobile devices and mobile networks. Secondly, the proposed conflict management technique provides users with conflict status and information so that users can handle and resolve conflicts appropriately. Thirdly, the proposed membership management algorithm ensures all participants receive all necessary updates and allows users to join a currently active collaboration session. Fourthly, the proposed document partitioning algorithm provides flexibility for users to work on selected parts of the document and reduces the resource consumption. Finally, a basic implementation of the framework is presented to show how it can support a real time collaboration scenario