Energy Efficient Neural Codes

1996 ◽  
Vol 8 (3) ◽  
pp. 531-543 ◽  
Author(s):  
William B Levy ◽  
Robert A. Baxter
Keyword(s):  
Energy Efficient ◽  
Metabolic Cost ◽  
Neural Systems ◽  
Average Firing Rate ◽  
Energy Expenditures ◽  
Coding Schemes ◽  
Representational Capacity ◽  
Minimal Redundancy ◽  
Efficient Information ◽  
The Cost

In 1969 Barlow introduced the phrase “economy of impulses” to express the tendency for successive neural systems to use lower and lower levels of cell firings to produce equivalent encodings. From this viewpoint, the ultimate economy of impulses is a neural code of minimal redundancy. The hypothesis motivating our research is that energy expenditures, e.g., the metabolic cost of recovering from an action potential relative to the cost of inactivity, should also be factored into the economy of impulses. In fact, coding schemes with the largest representational capacity are not, in general, optimal when energy expenditures are taken into account. We show that for both binary and analog neurons, increased energy expenditure per neuron implies a decrease in average firing rate if energy efficient information transmission is to be maintained.

scholarly journals Energy cost and muscular activity required for propulsion during walking

2003 ◽  
Vol 94 (5) ◽  
pp. 1766-1772 ◽  
Author(s):  
Jinger S. Gottschall ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Muscular Activity ◽  
Metabolic Cost ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Horizontal Force ◽  
Normal Walking ◽  
The Mean ◽  
The Cost ◽  
Muscle Actions

We reasoned that with an optimal aiding horizontal force, the reduction in metabolic rate would reflect the cost of generating propulsive forces during normal walking. Furthermore, the reductions in ankle extensor electromyographic (EMG) activity would indicate the propulsive muscle actions. We applied horizontal forces at the waist, ranging from 15% body weight aiding to 15% body weight impeding, while subjects walked at 1.25 m/s. With an aiding horizontal force of 10% body weight, 1) the net metabolic cost of walking decreased to a minimum of 53% of normal walking, 2) the mean EMG of the medial gastrocnemius (MG) during the propulsive phase decreased to 59% of the normal walking magnitude, and yet 3) the mean EMG of the soleus (Sol) did not decrease significantly. Our data indicate that generating horizontal propulsive forces constitutes nearly half of the metabolic cost of normal walking. Additionally, it appears that the MG plays an important role in forward propulsion, whereas the Sol does not.

scholarly journals Sustainable Retirement Living: What Matters?

2013 ◽  
Vol 1 (1) ◽  
pp. 56 ◽  
Author(s):  
Jake Barker ◽  
Bo Xia ◽  
George Zillante
Keyword(s):  
Sustainable Development ◽  
Questionnaire Survey ◽  
Energy Efficient ◽  
Energy Supply ◽  
Household Waste ◽  
Public Acceptance ◽  
Ageing Population ◽  
Cost Of Energy ◽  
The Cost ◽  
Survey Approach

There is a growing demand for sustainable retirement villages in Australia due to an increasing number of ageing population and public acceptance of sustainable development. This research aims to gain a better understanding of retirees’ understanding about sustainable retirement living and their attitudes towards sustainable developments via a questionnaire survey approach. The results showed that the current residents of retirement villages are generally very conscious of unsustainable resource consumption and would like their residences and community to be more environmentally friendly and energy efficient. The cost of energy supply is a concern to majority of respondents. However there is a certain level of concerns from residents too on the extra cost of going green in their residence. Education is required to residents about recycling household waste and how to use available facilities. A better understanding of retirees’ awareness and attitudes towards sustainability issues helps to improve the sustainable developments of retirement villages in the future.

Autonomous Energy Efficient Co-Generation Units

2014 ◽  
Vol 672-674 ◽  
pp. 580-584 ◽  
Author(s):  
Mikhail Petrichenko ◽  
Dmitriy Tseytin ◽  
Darya Nemova ◽  
Nikita Kharkov
Keyword(s):  
Mathematical Model ◽  
Energy Efficient ◽  
Energy Resources ◽  
The Cost ◽  
Liquefied Gas

The technology of application of the liquefied gas for the centralized providing with energy resources of a complex of building remote from network energy resources is considered in this work, the economic-mathematical model of the first approach of the concept of the device of the settlement, allowing to determine the cost of received energy and equipment payback periods is offered.

scholarly journals Metabolic cost of generating horizontal forces during human running

1999 ◽  
Vol 86 (5) ◽  
pp. 1657-1662 ◽  
Author(s):  
Young-Hui Chang ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Order Of Magnitude ◽  
Reaction Forces ◽  
The Cost ◽  
Support Body Weight ◽  
Human Running

Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o 2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o 2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o 2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.

scholarly journals Multiple purpose spin transfer torque operated devices

2013 ◽  
Vol 26 (3) ◽  
pp. 227-238
Author(s):  
Thomas Windbacher ◽  
Hiwa Mahmoudi ◽  
Alexander Makarov ◽  
Viktor Sverdlov ◽  
Siegfried Selberherr
Keyword(s):  
Information Processing ◽  
Building Block ◽  
Energy Efficient ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Spin Torque ◽  
Logic Device ◽  
Flip Flop ◽  
Sequential Logic ◽  
Efficient Information

We summarize our recent work on a non-volatile logic building block required for energy-efficient information processing systems. A sequential logic device, in particular, an alternative non-volatile magnetic flip-flop has been introduced. Its properties are investigated and its extension to a very dense shift register is demonstrated. We show that the flip-flop structure inherently exhibits oscillations and discuss its spin torque nano-oscillator properties.

scholarly journals Disentangling the energetic costs of step time asymmetry and step length asymmetry in human walking

2021 ◽  
Author(s):  
Jan Stenum ◽  
Julia T. Choi
Keyword(s):  
Energy Cost ◽  
Metabolic Cost ◽  
Step Length ◽  
Human Walking ◽  
Metabolic Power ◽  
Healthy Human ◽  
Time Asymmetry ◽  
Double Support ◽  
Post Stroke ◽  
The Cost

The metabolic cost of walking in healthy individuals increases with spatiotemporal gait asymmetries. Pathological gait, such as post-stroke, often has asymmetry in step lengths and step times which may contribute to an increased energy cost. But paradoxically, enforcing step length symmetry does not reduce metabolic cost of post-stroke walking. The isolated and interacting costs of asymmetry in step times and step lengths remain unclear, because previous studies did not simultaneously enforce spatial and temporal gait asymmetries. Here, we delineate isolated costs of asymmetry in step times and step lengths in healthy human walking. We first show that the cost of step length asymmetry is predicted by the cost of taking two non-preferred step lengths (one short and one long), but that step time asymmetry adds an extra cost beyond the cost of non-preferred step times. The metabolic power of step time asymmetry is about 2.5 times greater than the cost of step length asymmetry. Furthermore, the costs are not additive when walking with asymmetric step times and step lengths: metabolic power of concurrent asymmetry in step lengths and step times is driven by the cost of step time asymmetry alone. The metabolic power of asymmetry is explained by positive mechanical power produced during single support phases to compensate for a net loss of center of mass power incurred during double support phases. These data may explain why metabolic cost remains invariant to step length asymmetry in post-stroke walking and suggests how effects of asymmetry on energy cost can be attenuated.

scholarly journals A Long-term Strategy for Energy and Cost Performance Improvement of Existing Residential Buildings: Step-by-step Renovation in Turkey

2019 ◽  
Vol 111 ◽  
pp. 03040
Author(s):  
Touraj Ashrafian ◽  
Zerrin Yilmaz ◽  
Nazanin Moazzen
Keyword(s):  
Cost Analysis ◽  
Energy Efficient ◽  
Financial Incentives ◽  
Residential Buildings ◽  
Minimum Energy ◽  
Energy Performance ◽  
Optimal Level ◽  
Proper Solution ◽  
Existing Building ◽  
The Cost

Recast version of Energy Performance of Building Directive (EPBD-Recast) obligate member states to keep the cost analysis in parallel with the energy analysis during the renovation actions for the existing building by taking the cost-optimal level of minimum energy performance requirement to the account. Although this cost-optimal level is indicating the minimum cost level for a period, it can provide buildings’ owners with an enormous initial cost. One of the most challenging barriers to energy efficient and cost-optimal renovation of existing buildings is the reluctance of owners to involve in their project as an investor due to the high cost of application. Particularly in developing countries, such reluctance is more tangible as the governments are not capable of providing enough financial incentives for owners due to a large number of buildings that should be renovated and small available budget. A proper solution for the problem is to divide necessary actions for each building to certain sub-actions and apply them as a step-by-step renovation project. On the other hand, the progressive application of renovation activities has some restrictions. It is necessary to define the due amount for households and keep the cost of each step within the payable range. Moreover, the low rate of building renovation which affects the EU goals can be improved remarkably by application of step-by-step actions not only by increasing the number of owners’ contributions but also by improving the time of implementation, proper distribution of skilled labours and directed economic resources. This paper aims to assess the step-by-step application of the energy efficient renovation actions through energy and cost analysis under Turkey’s climatic, economic and sociological conditions. One of 26 reference residential buildings in Turkey is analysed in this paper. The due amount for each step is defined, and some renovation actions and their combinations applied to the case building and the results compared with the base condition. Then a proper combination of measures established based on the cost-optimal analyses. These appropriately combined actions are then divided into some sub-actions; following this, cost and energy studies are conducted again to determine the appropriate arrangement of sub-actions.

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