Optimal basis set for electronic structure calculations in periodic systems

An efficient method for calculating the electronic structure of systems that need a very fine sampling of the Brillouin zone is presented. The method is based on the variational optimization of a single (i.e., common to all points in the Brillouin zone) basis set for the expansion of the electronic orbitals. Considerations from k.p-approximation theory help to understand the efficiency of the method. The accuracy and the convergence properties of the method as a function of the optimal basis set size are analyzed for a test calculation on a 16-atom Na supercell.

a backtracking search tool for constructing combinatorial test suites

Combinatorial testing is an important testing method. It requires the test cases to cover various combinations of parameters of the system under test. The test generation problem for combinatorial testing can be modeled as constructing a matrix which has certain properties. This paper first discusses two combinatorial testing criteria: covering array and orthogonal array, and then proposes a backtracking search algorithm to construct matrices satisfying them. Several search heuristics and symmetry breaking techniques are used to reduce the search time. This paper also introduces some techniques to generate large covering array instances from smaller ones. All the techniques have been implemented in a tool called EXACT (EXhaustive seArch of Combinatorial Test suites). A new optimal covering array is found by this tool.

Optimal Code Set Selection and Security Issues in Spectral Phase-Encoded Time Spreading (SPECTS) OCDMA Systems

In this paper, we perform a thorough analysis of a spectral phase-encoded time spreading optical code division multiple access (SPECTS-OCDMA) system based on Walsh-Hadamard (W-H) codes aiming not only at finding optimal code-set selections but also at assessing its loss of security due to crosstalk. We prove that an inadequate choice of codes can make the crosstalk between active users to become large enough so as to cause the data from the user of interest to be detected by other user. The proposed algorithm for code optimization targets code sets that produce minimum bit error rate (BER) among all codes for a specific number of simultaneous users. This methodology allows us to find optimal code sets for any OCDMA system, regardless the code family used and the number of active users. This procedure is crucial for circumventing the unexpected lack of security due to crosstalk. We also show that a SPECTS-OCDMA system based on W-H 32(64) fundamentally limits the number of simultaneous users to 4(8) with no security violation due to crosstalk. More importantly, we prove that only a small fraction of the available code sets is actually immune to crosstalk with acceptable BER (<10(-9)) i.e., approximately 0.5% for W-H 32 with four simultaneous users, and about 1 x 10(-4)% for W-H 64 with eight simultaneous users.

Optimal Test for Parameter Instability When the Unstable Process and the Error Distribution are Unknown

This paper proposes asymptotically optimal tests for unstable parameter process under the feasible circumstance that the researcher has little information about the unstable parameter process and the error distribution, and suggests conditions under which the knowledge of those processes does not provide asymptotic power gains. I first derive a test under known error distribution, which is asymptotically equivalent to LR tests for correctly identified unstable parameter processes under suitable conditions. The conditions are weak enough to cover a wide range of unstable processes such as various types of structural breaks and time varying parameter processes. The test is then extended to semiparametric models in which the underlying distribution in unknown but treated as unknown infinite dimensional nuisance parameter. The semiparametric test is adaptive in the sense that its asymptotic power function is equivalent to the power envelope under known error distribution.

Operator's and unit maintenance manual for vinson interconnecting box : test set AN/USM-481, (NSN 6625-01-106-4296).

Includes index.

Operator's, organizational, direct support, and general support maintenance manual for test set, STE-M1/FVS (4910-01-112-9655).

"January 1985."

Direct support maintenance repair parts and special tools list for test set, electronics system AN/TSM-100A (4933-01-142-2861).

"February 1984."

Organizational, direct support, and general support maintenance repair parts and special tools list ... : test set, chemical agent automatic alarm, M74 (FSN 6665-854-4147).

"September 1973."

Organizational, direct support, and general support maintenance repair parts and special tools lists for test set, radio frequency power AN/USM-260 (NSN 6625-00-917-3099).

"September 1976."

Hand receipt covering contents of components of end item (COEI), basic issue items (BII), and additional authorization list (AAL) for radio test set AN/PRM-34 (NSN 6625-01-094-5646).

"2 September 1983."

Organizational, direct support, and general support maintenance repair parts and special tools lists (including depot maintenance repair parts and special tools) for test set, transponder set AN/APM-305A (NSN 6625-01-052-3881).

"June 1979."

Direct support maintenance repair parts and special tools lists (including depot maintenance repair parts and special tools) for test set, laser infrared observation device TS-3620/GVS-5 (NSN 5860-01-052-9477).

"September 1979."

Organizational, direct support, and general support maintenance repair parts and special tools list (including depot maintenance repair parts and special tools) for test set, radio, AN/GRM-114 (NSN 6625-01-108-6206).

"20 May 1983."