492 research outputs found
UZBEKISTAN MOD FOREIGN LANGUAGE APTITUDE TEST: A CRITICAL EVALUATION
Globalization has entailed a growth in impor-tance of the second/foreign language teachingand learning all over the world with the numberof both voluntary and involuntary language learn-ers increasing on daily basis. There is, however,a widely attested discrepancy in actual resultsachieved by those engaged in second/foreignlanguage learning usually explained by means ofinvocation of a specialized talent that certain in-dividuals have, whilst others lack. Such a talent isthought to be measurable and the results obtainedare regarded as valid predictors of success forintensive foreign language programs. The pres-ent article deals with critical appraisal of one ofsuch instruments in terms of both its theoreticaland practical validity. A number of points to beaddressed for the purpose of the instrument im-provement are demonstrated via referral to bothbasic statistic techniques and scientific consensusin the field of language learning aptitude research
Novel optical devices for information processing
Optics has the inherent advantages of parallelism and wide bandwidths in processing
information. However, the need to interface with electronics creates a bottleneck
that eliminates many of these advantages. The proposed research explores novel
optical devices and techniques to overcome some of these bottlenecks. To address
parallelism issues we take a specific example of a content-addressable memory that can
recognize images. Image recognition is an important task that in principle can be done
rapidly using the natural parallelism of optics. However in practice, when presented
with incomplete or erroneous information, image recognition often fails to give the
correct answer. To address this problem we examine a scheme based on free-space
interconnects implemented with diffractive optics. For bandwidth issues, we study
possible ways to eliminate the electronic conversion bottleneck by exploring all-optical
buffer memories and all-optical processing elements. For buffer memories we examine
the specific example of slow light delay lines. Although this is currently a popular
research topic, there are fundamental issues of the delay-time-bandwidth product
that must be solved before slow light delay lines can find practical applications. For
all-optical processing we examine the feasibility of constructing circuit elements that
operate directly at optical frequencies to perform simple processing tasks. Here we
concentrate on the simplest element, a sub-wavelength optical wire, along with a
grating coupler to interface with conventional optical elements such as lenses and
fibers. Even such a simple element as a wire has numerous potential applications. In conclusion, information processing by all-optical devices are demonstrated with
an associative memory using diffractive optics, an all-optical delay line using room
temperature slow light in photorefractive crystals, and a subwavelength optical circuit
by surface plasmon effects
Coordination of supply chain inventory systems with private information
This dissertation considers the problems of coordinating different supply chain
inventory systems with private information under deterministic settings. These systems
studied are characterized by the following properties: (a) each facility in the system has
self decision-making authority, (b) cost parameters of each facility are regarded as
private information that no other facilities in the system have access to, and (c) partial
information is shared among the facilities. Because of the above properties, the existing
approaches for systems with global information may not be applicable. Thus, new
approaches for coordinating supply chain inventory systems with private information are
needed.
This dissertation first studies two two-echelon distribution inventory systems.
Heuristics for finding the replenishment policy of each facility are developed under
global information environment. In turn, the heuristics are modified to solve the
problems with private information. An important characteristic of the heuristics
developed for the private information environment is that they provide the same
solutions as their global information counterpart.
Then, more complex multi-echelon serial and assembly supply chain inventory
systems with private information are studied. The solution approach decomposes the
problem into separate subproblems such that the private information is divided as
required. Global optimality is sought with an iterative procedure in which the
subproblems negotiate the material flows between facilities. At the core of the solution procedure is a node-model that represents a facility and its corresponding private
information. Using the node-model as a building block, other supply chains can be
formed by linking the node-models according to the product and information flows. By
computational experiments, the effect of the private information on the performance of
the supply chain is tested by comparing the proposed approach against existing
heuristics that utilize global information. Experimental results show that the proposed
approach provides comparable results as those of the existing heuristics with global
information
Layout optimization in ultra deep submicron VLSI design
As fabrication technology keeps advancing, many deep submicron (DSM) effects have become
increasingly evident and can no longer be ignored in Very Large Scale Integration
(VLSI) design. In this dissertation, we study several deep submicron problems (eg. coupling
capacitance, antenna effect and delay variation) and propose optimization techniques
to mitigate these DSM effects in the place-and-route stage of VLSI physical design.
The place-and-route stage of physical design can be further divided into several steps:
(1) Placement, (2) Global routing, (3) Layer assignment, (4) Track assignment, and (5) Detailed
routing. Among them, layer/track assignment assigns major trunks of wire segments
to specific layers/tracks in order to guide the underlying detailed router. In this dissertation,
we have proposed techniques to handle coupling capacitance at the layer/track assignment
stage, antenna effect at the layer assignment, and delay variation at the ECO (Engineering
Change Order) placement stage, respectively. More specifically, at layer assignment, we
have proposed an improved probabilistic model to quickly estimate the amount of coupling
capacitance for timing optimization. Antenna effects are also handled at layer assignment
through a linear-time tree partitioning algorithm. At the track assignment stage, timing is
further optimized using a graph based technique. In addition, we have proposed a novel
gate splitting methodology to reduce delay variation in the ECO placement considering
spatial correlations. Experimental results on benchmark circuits showed the effectiveness
of our approaches
Hypsometry and Volume of the Arctic Ocean and Its Constituent Seas
This paper presents an analysis of the Arctic Ocean and its constituent seas for seafloor area distribution versus depth and ocean volume. The bathymetry from the International Bathymetric Chart of the Arctic Ocean (IBCAO) is used together with limits defining this ocean and its constituent seas from the International Hydrographic Organization (IHO) as well as redefined limits constructed to confine the seas to the shallow shelves. IBCAO is a bathymetric grid model with a resolution of 2.5 x 2.5 km, which significantly improved the portrayal of the Arctic Ocean seafloor through incorporation of newly released bathymetric data including echo soundings from U.S. and British navies, scientific nuclear submarine cruises, and icebreaker cruises. This analysis of seafloor area and ocean volume is the first for the Arctic Ocean based on this new and improved portrayal of the seafloor as represented by IBCAO. The seafloor area and volume are calculated for different depths starting from the present sea level and progressing in increments of 10 m to a depth of 500 m and in increments of 50 m from 550 m down to the deepest depth within each of the analyzed seas. Hypsometric curves expressed as simple histograms of the frequencies in different depth bins and depth plotted against cumulative area for each of the analyzed seas are presented. The area and volume calculations show that the entire IHO-defined Arctic Ocean makes up 4.3% of the total ocean area but only 1.4% of the volume. Furthermore, the IHO Arctic Ocean is the shallowest (mean depth 1201 m) of all the major oceans and their adjacent seas. The continental shelf area, from the coasts out to the shelf break, make up as much as 52.9% of the total area in the Arctic Ocean, defined in this work as consisting of the oceanic deep Arctic Ocean Basin; the broad continental shelves of the Barents, Kara, Laptev, East Siberian, Chukchi, and Beaufort Seas; the White Sea; and the narrow continental shelf off both the Canadian Arctic Archipelago and northern Greenland. This result indicates that the Arctic Ocean has significantly larger continental shelves compared with all the other oceans, where previous studies show that the proportion of shelves, from the coasts out to the foot of the continental slopes, only ranges between about 9.1 and 17.7%. Furthermore, the derived hypsometric curves show that most of the Arctic Ocean shelf seas besides the Barents Sea, Beaufort Sea, and the shelf off northern Greenland have a similar shape, with the largest seafloor area between 0 and 50 m. The East Siberian and Laptev seas, in particular, show area distributions concentrated in this shallow depth range, and together with the Chukchi Sea they form a large flat shallow shelf province composing as much as 22% of the entire Arctic Ocean area but only 1% of the volume. This implies that the circulation in the Arctic Ocean might be very sensitive to eustatic sea level changes. One of the aims with this work is to make up-to-date high-resolution area and volume calculations for the Arctic Ocean at various depths available for download
Some Results in the Hyperinvariant Subspace Problem and Free Probability
This dissertation consists of three more or less independent projects. In the first
project, we find the microstates free entropy dimension of a large class of L1[0; 1]{
circular operators, in the presence of a generator of the diagonal subalgebra.
In the second one, for each sequence {cn}n in l1(N), we de fine an operator A in
the hyper finite II1-factor R. We prove that these operators are quasinilpotent and
they generate the whole hyper finite II1-factor. We show that they have non-trivial,
closed, invariant subspaces affiliated to the von Neumann algebra, and we provide
enough evidence to suggest that these operators are interesting for the hyperinvariant
subspace problem. We also present some of their properties. In particular, we
show that the real and imaginary part of A are equally distributed, and we find a
combinatorial formula as well as an analytical way to compute their moments. We
present a combinatorial way of computing the moments of A*A.
Finally, let fTkg1k =1 be a family of *-free identically distributed operators in a
finite von Neumann algebra. In this paper, we prove a multiplicative version of the
Free Central Limit Theorem. More precisely, let Bn = T*1T*2...T*nTn...T2T1 then
Bn is a positive operator and B1=2n
n converges in distribution to an operator A. We
completely determine the probability distribution v of A from the distribution u of
jTj2. This gives us a natural map G : M M with u G(u) = v. We study
how this map behaves with respect to additive and multiplicative free convolution. As an interesting consequence of our results, we illustrate the relation between the
probability distribution v and the distribution of the Lyapunov exponents for the
sequence fTkg1k=1 introduced by Vladismir Kargin
Jumpstart at UMass Boston
Jumpstart is a national early education organization that recruits and trains college students to serve preschool children in low-income neighborhoods. Our proven curriculum helps children develop the language and literacy skills they need to be ready for kindergarten, setting them on a path to close the achievement gap before it is too late
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