95 research outputs found
COMPARATIVE EDUCATION IN THE EDUCATIONAL SYSTEMS AND PROBLEMS IN LIKENESSES AND DIFFERENCES BETWEEN REGIONS OF THE WORLD
This paper is to consider the term “comparative” in its more restricted sense, in the way the term is used in various comparative fields of study. It is somewhat curious that scholars in our field of comparative education have never attempted to sort out the various meanings of the term “comparative.” I do not plan to draw a firm distinction between the two spheres, though it might be helpful to suggest that “comparative education” is generally regarded as the more academic or scientific aspect of the field, while international education is related to “cooperation, understanding, and exchange” elements of the field. I feel we must reject the hegemonic claims of science. We recall, for example, that Comte believed society traversed through various stages, from religion, to philosophy, then to science. His mistake, from my vantage point, was to place these ways of knowing in a hierarchical framework, which makes philosophy a second-rate means of knowing, and religion a third-rate means of knowing. My own orientation is to place them parallel with each other. There is a place for the spiritual, a place for the philosophical, and a place for the scientific, and any attempt to place one exclusively over the other is inappropriate
Context-Free Path Querying with Structural Representation of Result
Graph data model and graph databases are very popular in various areas such
as bioinformatics, semantic web, and social networks. One specific problem in
the area is a path querying with constraints formulated in terms of formal
grammars. The query in this approach is written as grammar, and paths querying
is graph parsing with respect to given grammar. There are several solutions to
it, but how to provide structural representation of query result which is
practical for answer processing and debugging is still an open problem. In this
paper we propose a graph parsing technique which allows one to build such
representation with respect to given grammar in polynomial time and space for
arbitrary context-free grammar and graph. Proposed algorithm is based on
generalized LL parsing algorithm, while previous solutions are based mostly on
CYK or Earley algorithms, which reduces time complexity in some cases.Comment: Evaluation extende
One Parser to Rule Them All
Despite the long history of research in parsing, constructing parsers for real programming languages remains a difficult and painful task. In the last decades, different parser generators emerged to allow the construction of parsers from a BNF-like specification. However, still today, many parsers are handwritten, or are only partly generated, and include various hacks to deal with different peculiarities in programming languages. The main problem is that current declarative syntax definition techniques are based on pure context-free grammars, while many constructs found in programming languages require context information.
In this paper we propose a parsing framework that embraces context information in its core. Our framework is based on data-dependent grammars, which extend context-free grammars with arbitrary computation, variable binding and constraints. We present an implementation of our framework on top of the Generalized LL (GLL) parsing algorithm, and show how common idioms in syntax of programming languages such as (1) lexical disambiguation filters, (2) operator precedence, (3) indentation-sensitive rules, and (4) conditional preprocessor directives can be mapped to data-dependent grammars. We demonstrate the initial experience with our framework, by parsing more than 20000 Java, C#, Haskell, and OCaml source files
Generation of THz frequency using PANDA ring resonator for THz imaging
In this study, we have generated terahertz (THz) frequency by a novel design of microring resonators for medical applications. The dense wavelength-division multiplexing can be generated and obtained by using a Gaussian pulse propagating within a modified PANDA ring resonator and an add/drop filter system. Our results show that the THz frequency region can be obtained between 40–50 THz. This area of frequency provides a reliable frequency band for THz pulsed imaging
Operator precedence for data-dependent grammars
Constructing parsers based on declarative specification of operator precedence is a very old research topic, and there are various existing approaches. However, these approaches are either tied to a particular parsing technique, or cannot deal with all corner cases found in programming languages. In this paper we present an implementation of declarative specification of operator precedence for general parsing that (1) is independent of the underlying parsing algorithm, (2) does not require any grammar transformation that increases the size of the grammar, (3) preserves the shape of parse trees of the original, natural grammar, and (4) can deal with intricate cases of operator precedence found in functional programming languages such as OCaml. Our new approach to operator precedence is formulated using data-dependent grammars, which extend context-free grammars with arbitrary computation, variable binding and constraints. We implemented our approach using Iguana, a data-dependent parsing framework, and evaluated it by parsing Java and OCaml source files. The results show that our approach is practical for parsing programming languages with complicated operator precedence rules
The FastLanes compression layout: Decoding >100 billion integers per second with scalar code
The open-source Fast Lanes project aims to improve big data formats, such as Parquet, ORC and columnar database formats, in multiple ways. In this paper, we significantly accelerate decoding of all common Light-Weight Compression (LWC) schemes: DICT, FOR, DELTA and RLE through better data-parallelism. We do so by re-designing the compression layout using two main ideas: (i) generalizing the value interleaving technique in the basic operation of bit-(un)packing by targeting a virtual 1024-bits SIMD register, (ii) reordering the tuples in all columns of a table in the same Unified Transposed Layout that puts tuple chunks in a common "104261537" order (explained in the paper); allowing for maximum independent work for all possible basic SIMD lane widths: 8, 16, 32, and 64 bits. We address the software development, maintenance and future proofness challenges of increasing hardware diversity, by defining a virtual 1024-bits instruction set that consists of simple operators supported by all SIMD dialects; and also, importantly, by scalar code. The interleaved and tuple-reordered layout actually makes scalar decoding faster, extracting more data-parallelism from today’s wide-issue CPUs. Importantly, the scalar version can be fully auto-vectorized by modern compilers, eliminating technical debt in software caused by platform-specific SIMD intrinsics. Micro-benchmarks on Intel, AMD, Apple and AWS CPUs show that Fast Lanes accelerates decoding by factors (decoding > 40 values per CPU cycle). Fast Lanes can make queries faster, as compressing the data reduces bandwidth needs, while decoding is almost free
The FastLanes Compression Layout: Decoding >100 billion integers per second with scalar code
The open-source FastLanes project aims to improve big data formats,
such as Parquet, ORC and columnar database formats, in
multiple ways. In this paper, we significantly accelerate decoding
of all common Light-Weight Compression (LWC) schemes: DICT,
FOR, DELTA and RLE through better data-parallelism. We do so
by re-designing the compression layout using two main ideas: (i)
generalizing the value interleaving technique in the basic operation
of bit-(un)packing by targeting a virtual 1024-bits SIMD register, (ii)
reordering the tuples in all columns of a table in the same Unified
Transposed Layout that puts tuple chunks in a common “04261537”
order (explained in the paper); allowing for maximum independent
work for all possible basic SIMD lane widths: 8, 16, 32, and 64 bits.
We address the software development, maintenance and futureproofness
challenges of increasing hardware diversity, by defining
a virtual 1024-bits instruction set that consists of simple operators
supported by all SIMD dialects; and also, importantly, by scalar
code. The interleaved and tuple-reordered layout actually makes
scalar decoding faster, extracting more data-parallelism from today’s
wide-issue CPUs. Importantly, the scalar version can be fully
auto-vectorized by modern compilers, eliminating technical debt
in software caused by platform-specific SIMD intrinsics.
Micro-benchmarks on Intel, AMD, Apple and AWS CPUs show
that FastLanes accelerates decoding by factors (decoding >40 values
per CPU cycle). FastLanes can make queries faster, as compressing
the data reduces bandwidth needs, while decoding is almost free
Safe Specification of Operator Precedence Rules
International audienceIn this paper we present an approach to specifying opera- tor precedence based on declarative disambiguation constructs and an implementation mechanism based on grammar rewriting. We identify a problem with existing generalized context-free parsing and disambigua- tion technology: generating a correct parser for a language such as OCaml using declarative precedence specification is not possible without resorting to some manual grammar transformation. Our approach provides a fully declarative solution to operator precedence specification for context-free grammars, is independent of any parsing technology, and is safe in that it guarantees that the language of the resulting grammar will be the same as the language of the specification grammar. We evaluate our new approach by specifying the precedence rules from the OCaml reference manual against the highly ambiguous reference grammar and validate the output of our generated parser
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