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The ability to remember past experiences enables a system to improve its performance as well as its competence. For example, a system might be able solve problems faster by adapting previous solutions. Additional tasks, such as avoiding unwanted behavior by detecting potential problems, monitoring long-term goals by remembering what subgoals have been achieved, and reflection on past actions, become feasible. As the tasks that an intelligent system accomplishes become more and more complex, so does the experience it acquires in the process. Such experience has a temporal extent and is expressed in terms of concepts and relations with deep semantics associated to them. Memory systems should be able to deal with the temporal aspect of experience, exploit this semantic knowledge for storage and retrieval and do so in a scalable fashion. However, relying just on experience will not achieve a broad coverage, as it needs to be used in conjunction with other reasoning mechanisms. That is why we need the ability to add episodic memory functionality to intelligent systems. Today's knowledge-based systems are complex software applications and the ability to develop them in a modular fashion, using generic, reusable components is essential. We propose to separate the episodic memory from the system that uses it and to build a generic, reusable memory module that can be attached to a variety of applications in order to provide this functionality. Its goal is to provide accurate, scalable, efficient and content-addressable access to prior episodes. Having such a reusable memory module should allow research to focus on the generic aspects of memory representation, organization and retrieval and its interaction with the external application and it should also reduce the complexity of the overall system. In this dissertation we propose a set of general requirements that any memory module should provide regarding memory encoding, storage and retrieval. We present an implementation that satisfies these requirements and evaluate it on three different tasks: plan synthesis, plan recognition and Physics problem solving. The memory module proved easily adaptable to these tasks, providing fast, accurate and scalable retrieval.

Mainstream non-volatile memory technology dominated by the planar Flash transistor with continuous floating-gate has been historically improved in density and performance primarily by means of process scaling, but is currently faced with significant hindrances to its future scaling due to fundamental constraints of electrostatics and reliability. This dissertation is based on exploring two pathways for circumventing scaling limitations of the state-of-the-art Flash memory technology. The first part of the dissertation is based on demonstrating a vertical Flash memory transistor with nanocrystal floating-gate, while the second part is based on developing fundamental understanding of the operation of Phase Change Memory. A vertical Flash transistor can allow the theoretical minimum cell area and a nanocrystal floating-gate on the sidewalls is shown to allow a thinner gate-stack further conducive to scaling while still providing good reliability. Subsequently, the application of a technique of protein-mediated assembly of preformed nanocrystals to the sidewalls of the vertical Flash transistor is also demonstrated and characterized. This technique of ordering pre-formed nanocrystals is beneficial towards achieving reproducible nanocrystal size uniformity and ordering especially in a highly scaled vertical Flash cell, rendering it more amenable to scaling and manufacturability. In both forms, the vertical Flash memory cell is shown to have good electrical characteristics and reliability for the viability of this cell design and implementation. In the remaining part of this dissertation, studies are undertaken towards developing fundamental understanding of the operational characteristics of Phase Change Memory (PCM) technology that is expected to replace floating-gate Flash technology based on its potential for scaling. First, a phenomenon of improving figures of merit of the PCM cell with operational cycles is electrically characterized. Based on the electrical characterization and published material characterization data, a physical model of an evolving "active region" of the cell is proposed to explain the improvement of the cell parameters with operational cycles. Then, basic understanding is developed on early and erratic retention failure in a statistically significant number of cells in a large array and, electrical characterization and physical modeling is used to explain the mechanism behind the early retention failure.

The injection operator for a carbon dioxide sequestration project must control the reservoir and associated pore space within the project boundaries to allow for orderly development of the storage facility. A large number of interest owners within a project area is likely to make reaching unanimous agreement among all owners of pore space unlikely, and thus control of the reservoir difficult. In order to facilitate geologic sequestration of carbon dioxide on privately owned land in the United States, or on land for which the minerals or pore space are privately owned, a scheme for aggregating the ownership of pore space is needed. To allow geologic sequestration projects to move forward with less than unanimous consent of interest owners, states can employ various methods of aggregating pore space ownership. This paper examines oil and gas unitization statues and statutes creating groundwater districts to find legislative regimes useful for achieving pore space ownership aggregation. Among the approaches discussed, aggregation of pore space ownership through a unitization model is the most likely choice. Taking that one step further and setting up new unit operating agreements for enhanced oil recovery to serve as a repository for incremental geologic sequestration, and eventual full sequestration activities, provides a firm path toward reducing carbon dioxide emissions while respecting property rights. This paper also compares the few existing pore space aggregation statutes in the United States, which achieve aggregation of pore space ownership through either unitization or eminent domain. The state that appears to be the best equipped to deal with aggregation of pore space ownership is Wyoming. Wyoming has been a leader in developing legislation to deal with pore space ownership before other states. North Dakota and Utah are also very well situated to move forward with carbon sequestration activities. / text

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Revised 06/2015; Originally published: 07/2006 / 3 pp. / Nutritious food is an important part of individual health and wellness. One way to ensure food is nutritious is to check the date on packages. The date is a guideline to help consumers use food when it is at its peak quality or before spoilage begins. Proper storage conditions and times are also essential in keeping healthy food safe to consume.

All energy, wind, water, biofuel and fossil fuel besides nuclear- and tide power originates from the sun. It’s very hard to take full advantage of the huge amount of energy hitting the earth each day from the sun. The suns highest radiation appears often when the energy need reaches its lowest. That’s why it’s very important to be able to store energy over time when the sun doesn’t shine. A large part of energy storage is thermal energy storage, which can either be done sensible, latent or chemical. Another possible thermal storage is a combination of sensible and latent. This exam was aiming to investigate different types of energy storage methods available on the market and a much more detailed analysis for different storage methods with phase change materials (PCM). A new method was designed for a new storage tank suitable for Absolicon Solar Collector AB and their energy park in the city of Härnösand. The methods for this exam were to create a theoretical storage tank suitable to Absolicons Energy Park with some simple calculations. The criteria for the storage tank was to create a storage tank that could provide the district heat in Härnösand with 160 degrees pressurized water and create 160 degrees steam to the industry. The dimensions of the storage tank where chosen by the conditions in Härnösand and from the specific data of Härnösands district heat and from Absolicons new solar collectors. The work temperature of the system were set to 160 degrees which meant that the storage tank would be able to work in those conditions with high temperature. A suitable phase change material and methods for encapsulation of the phase change material suitable for this system was to be found. Small tests were made with a new type of encapsulation for phase change materials in higher temperature. Simple calculations of two types of storage tanks were made. The first storage tank was made with a PCM from PCM products named A164. This PCM was encapsulated with special bags that could handle temperature up to 200 degrees with surrounding rapeseed oil and a copper loop that handled the heat transfer. The second thank was made with the same PCM and encapsulation but with water glycol surrounding the PCM and two types of heat exchangers for the heat transfer. The results from the first tank were that it didn’t work with the district heat. Because a wrong calculation with the schematic of the system made it impossible to connect into the district heat of Härnösand. The only good thing was that it didn’t need to be pressurized because of the rapeseed oil but the bad heat transfer between oil and water made a pressurized tank of water more profitable. The results from the second tank showed that it could produce 160 °C to the district heat for 2 h and 7 minutes. The schematic connection worked and the tank would in the near future be able to connect into the district heat. The result for the encapsulation showed that the bags were able to stand temperatures up to 190 degrees for a short period of time.