2,639 research outputs found
Exploring item response theory in forced choice psychometrics for construct and trait interpretation in cross-cultural context
This thesis explores item response theory (IRT) in the Personal Profile Analysis (PPA)
from Thomas International. The study contains two parts (Part 1 and Part II) for which
two sample groups were collected. For Part I of the research 650 participants were
collected via the old form (CPPA25/C7) in the Beijing office of Thomas International in
China (male=323, Female=267, missing=60). Part II of the research used the
amended form in the same area and collected a sample of 307 (male=185, female=119,
missing=3).
The study postulates that IRT methods are applicable to forced-choice psychometrics.
The results of Part I showed that the current CPPA form functions, to some extent,
according to PPA’s original constructs. Part I of the research identified 16 items that
need to be amended (called Amend A in this research). The amended form was
returned to China for the collection of samples for Part II, and the results are deemed
acceptable.
The study concludes with a research protocol for PPA-IRT research generated from the
current research. The research protocol suggests four levels of analysis for forced
choice (FC) psychometrics, namely: 1. Textual analysis, 2. Functional analysis, 3.
Dynamic analysis, and 4. Construct analysis.PsychologyM.A. (Psychology
Redetermination of Ce[B5O8(OH)(H2O)]NO3·2H2O
The crystal structure of Ce[B5O8(OH)(H2O)]NO3·2H2O, cerium(III) aquahydroxidooctaoxidopentaborate nitrate dihydrate, has been redetermined from single-crystal X-ray diffraction data. In contrast to the previous determination [Li et al. (2003 ▶). Chem. Mater.
15, 2253–2260], the present study reveals the location of all H atoms, slightly different fundamental building blocks (FBBs) of the polyborate anions, more reasonable displacement ellipsoids for all non-H atoms, as well as a model without disorder of the nitrate anion. The crystal structure is built from corrugated polyborate layers parallel to (010). These layers, consisting of [B5O8(OH)(H2O)]2− anions as FBBs, stack along [010] and are linked by Ce3+ ions, which exhibit a distorted CeO10 coordination sphere. The layers are additionally stabilized via O—H⋯O hydrogen bonds between water molecules and nitrate anions, located at the interlayer space. The [BO3(H2O)]-group shows a [3 + 1] coordination and is considerably distorted from a tetrahedral configuration. Bond-valence-sum calculation shows that the valence sum of boron is only 2.63 valence units (v.u.) when the contribution of the water molecule (0.49 v.u.) is neglected
Give me a hint: An ID-free small data transmission protocol for dense IoT devices
IoT (Internet of Things) has attracted a lot of attention recently. IoT devices need to report their data or status to base stations at various frequencies. The IoT communications observed by a base station normally exhibit the following characteristics: (1) massively connected, (2) lightly loaded per packet, and (3) periodical or at least mostly predictable. The current design principals of communication networks, when applied to IoT scenarios, however, do not fit well to these requirements. For example, an IPv6 address is 128 bits, which is much longer than a 16-bit temperature report. Also, contending to send a small packet is not cost-effective. In this work, we propose a novel framework, which is slot-based, schedule-oriented, and identity-free for uploading IoT devices' data. We show that it fits very well for IoT applications. The main idea is to bundle time slots with certain hashing functions of device IDs, thus significantly reducing transmission overheads, including device IDs and contention overheads. The framework is applicable from small-scale body-area (wearable) networks to large-scale massively connected IoT networks. Our simulation results verify that this framework is very effective for IoT small data uploading
r-Hint: A message-efficient random access response for mMTC in 5G networks
Massive Machine Type Communication (mMTC) has attracted increasing attention due to the explosive growth of IoT devices. Random Access (RA) for a large number of mMTC devices is especially difficult since the high signaling overhead between User Equipments (UEs) and an eNB may overwhelm the available spectrum resources. To address this issue, we propose “respond by hint” (r-Hint), an ID-free handshaking protocol for contention-based RA in mMTC. The core idea of r-Hint is to avoid sequentially notifying contending UEs of their IDs by broadcasting a hint in the RA Response (RAR). To do so, we exploit the concept of prime factorization and hashing to encode the hint such that UEs can extract their required information accordingly. Our simulation results show that r-Hint reduces the RAR message size by 20%–40%. Such reduction can be translated to around 50% improvement of spectrum efficiency in LTE-M
Spiniform phase-encoded metagratings entangling arbitrary rational-order orbital angular momentum
Quantum entanglements between integer-order and fractional-order orbital angular momentums (OAMs) have been previously discussed.
However, the entangled nature of arbitrary rational-order OAM has long been considered a myth due to the absence of
an effective strategy for generating arbitrary rational-order OAM beams. Therefore, we report a single metadevice comprising a
bilaterally symmetric grating with an aperture, creating optical beams with dynamically controllable OAM values that are continuously
varying over a rational range. Due to its encoded spiniform phase, this novel metagrating enables the production of an
average OAM that can be increased without a theoretical limit by embracing distributed singularities, which differs significantly
from the classic method of stacking phase singularities using fork gratings. This new method makes it possible to probe the
unexplored niche of quantum entanglement between arbitrarily defined OAMs in light, which could lead to the complex manipulation
of microparticles, high-dimensional quantum entanglement and optical communication. We show that quantum coincidence
based on rational-order OAM-superposition states could give rise to low cross-talks between two different states that
have no significant overlap in their spiral spectra. Additionally, future applications in quantum communication and optical micromanipulation
may be found
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