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This paper aims at clarifying key points for realizing sustainable energy supply under restrictions on resource and environment. For this purpose, we first developed a database to estimate life cycle efficiencies and greenhouse gas emissions for various energy systems. Then on the basis of this life cycle assessment, we quantitatively define the concept of ‘Sustainability Limitations’ on resource depletion and environmental emissions. From this concept, present world is judged to be unsustainable both from resource and environmental viewpoints. At the same time, we clarify how far present world is from Sustainability Limitations. Then we describe our mathematical model simulating global energy supply and demand in ultra-long term. In this model, the concept of Sustainability Limitations is utilized so as to impose economic incentives to make energy system shift to a sustainable one in long term. Sustainability limitations of resource depletion and CO2 emissions are taken into consideration. As energy resources, this model includes coal, oil, natural gas, other unconventional fossil fuels, uranium and renewable resources. As energy technologies, it includes major technologies of mining, transport, conversion and final utilization. Computed results have shown that present energy system, which is judged to be unsustainable, shifts to a sustainable system in the ultra-long term with appropriate incentives.

We propose a hierarchical multi-module leaning system based on self-interpretation of instructions by coach. The proposed method enables a robot to decompose (i) a long term task which needs various kinds of information into a sequence of short term subtasks which need much less information through its self-interpretation process for the instructions given by coach, (ii) to select sensory information needed to each subtask, and (iii) to integrate the learned behaviors to accomplish the given long term task. We show a preliminary result of a simple soccer situation in the context of RoboCup.

This paper aims at evaluating technologies to realise a sustainable energy system within the constraints of resources and environment. For this purpose, we first developed a database to estimate life cycle efficiencies and greenhouse gas emissions for various energy technologies. Then, on the basis of this life cycle assessment, we quantitatively define the concept of sustainability limitations on resource depletion and environmental emissions. From this concept, the present energy system of the world is judged to be unsustainable from both resource and environmental viewpoints. Then, various mitigation measures such as disposal of CO2 and solar power generation are evaluated utilising the concept. The evaluated result showed how sustainability influences cost–effectiveness of the measures. At the same time we clarified the key points to realise a sustainable energy scenario in ultra–long term.