Response and optimization of an isolation system with relaxation type damping

Response and optimization of isolation system with relaxation type dampin

Reconciling Cadastral Records in a Dual Land Registration System in Ghana

Soon after gaining independence, the Ghana government adopted a deed registration system for recording land ownership. A legislative instrument supported this decision. The deficiencies of the deed registration system resulted in innumerable cases of land ownership disputes. Juxtaposed with the official registration system is the customary land tenure system, which authorized custodians of the stool lands to allocate parcels through the customary process. Because the customary system did not mandate documentary evidence of the transaction, the allocation process created situations where the same parcel of land was allocated to multiple owners. The weaknesses in the two systems engendered lucrative, illegal and unrecorded land market activities. With increasing population and associated competing interests in available land, it became imperative for the government to review the existing legislation for recording and maintaining records of land parcel ownership. A new legislation was promulgated, based on a land title registration system. While efforts are being made to improve the customary land allocation process, the new legislation seeks to remove the deficiencies in the deed registration system. The introduction of the title registration system has resulted in a duality of the record keeping process. Efforts are currently under way to remove the inconsistencies in the deed records and to reconcile them with those that have been obtained through the title registration system. This paper reviews the cadastral surveying activities and the processes for recording land titles in Ghana in view of existing laws. Experiences in developing procedures for reconciling the records from the two systems are also discussed. Keywords: Cadastral survey, land records, land tenure, registration, survey regulation Journal of Science and Technology Vol. 28 (1) 2008 pp. 128-13

The development of thirty self-administering and self-scoring elaborative thinking exercises

Thesis (Ed.M.)--Boston Universit

Numerical Optimization of the Thermal Field in Bridgman Detached Growth

The global modeling of the thermal field in two vertical Bridgman-like crystal growth configurations, has been performed to get optimal thermal conditions for a successful detached growth of Ge and CdTe crystals. These computations are performed using the CrysMAS code and expand upon our previous analysis [1] that propose a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. The analysis of the vertical Bridgman configuration with two heaters, used by Palosz et al. for the detached growth of Ge, shows, consistent with their results, that the large wetting angle of germanium on boron nitride surfaces was an important factor to promote a successful detached growth. Our computations predict that by initiating growth much higher into the hot zone of the furnace, the thermal conditions will be favorable for continued detachment even for systems that did not exhibit high contact angles. The computations performed for a vertical gradient freeze configuration with three heaters representative of that used for the detached growth of CdTe, show favorable thermal conditions for dewetting during the entirely growth run described. Improved thermal conditions are also predicted for coated silica crucibles when the solid-liquid interface advances higher into the hot zone during the solidification process. The second set of experiments on CdTe growth described elsewhere has shown the reattachment of the crystal to the crucible after few centimeters of dewetted growth. The thermal modeling of this configuration shows a second solidification front appearing at the top of the sample and approaching the middle line across the third heater. In these conditions, the crystal grows detached from the bottom, but will be attached to the crucible in the upper part because of the solidification without gap in this region. The solidification with two interfaces can be avoided when the top of the sample is positioned below the middle position of the third furnace

Compact fermion to qubit mappings

Mappings between fermions and qubits are valuable constructions in physics. To date only a handful exist. In addition to revealing dualities between fermionic and spin systems, such mappings are indispensable in any quantum simulation of fermionic physics on quantum computers. The number of qubits required per fermionic mode, and the locality of mapped fermionic operators strongly impact the cost of such simulations. We present a fermion to qubit mapping that outperforms all previous local mappings in both the qubit to mode ratio and the locality of mapped operators. In addition to these practically useful features, the mapping bears an elegant relationship to the toric code, which we discuss. Finally, we consider the error mitigating properties of the mapping—which encodes fermionic states into the code space of a stabilizer code. Although there is an implicit tradeoff between low weight representations of local fermionic operators, and high distance code spaces, we argue that fermionic encodings with low-weight representations of local fermionic operators can still exhibit error mitigating properties which can serve a similar role to that played by high code distances. In particular, when undetectable errors correspond to “natural” fermionic noise. We illustrate this point explicitly both for this encoding and the Verstraete-Cirac encoding

A scalable system for factored learning in the cloud

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 79-81).This work presents FlexGP, a new system designed for scalable machine learning in the cloud. FlexGP presents a learner-agnostic, data-parallel approach to cloud-based distributed learning using existing single-machine algorithms, without any dependence on distributed file systems or shared memory between instances. We design and implement asynchronous and decentralized launch and peer discovery protocols to start and configure a distributed network of learners. Through a unique process of factoring the data and parameters across the learners, FlexGP ensures this network consists of heterogeneous learners producing diverse models. These models are then filtered and fused to produce a meta-model for prediction. Using a thoughtfully designed test framework, FlexGP is run on a real-world regression problem from a large database. The results demonstrate the reliability and robustness of the system, even when learning from very little training data and multiple factorings, and demonstrate FlexGP as a vital tool to effectively leverage the cloud for machine learning tasks.by Owen C. Derby.M. Eng